1# SPDX-License-Identifier: GPL-2.0+ 2# 3# (C) Copyright 2000 - 2013 4# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 5 6Summary: 7======== 8 9This directory contains the source code for U-Boot, a boot loader for 10Embedded boards based on PowerPC, ARM, MIPS and several other 11processors, which can be installed in a boot ROM and used to 12initialize and test the hardware or to download and run application 13code. 14 15The development of U-Boot is closely related to Linux: some parts of 16the source code originate in the Linux source tree, we have some 17header files in common, and special provision has been made to 18support booting of Linux images. 19 20Some attention has been paid to make this software easily 21configurable and extendable. For instance, all monitor commands are 22implemented with the same call interface, so that it's very easy to 23add new commands. Also, instead of permanently adding rarely used 24code (for instance hardware test utilities) to the monitor, you can 25load and run it dynamically. 26 27 28Status: 29======= 30 31In general, all boards for which a configuration option exists in the 32Makefile have been tested to some extent and can be considered 33"working". In fact, many of them are used in production systems. 34 35In case of problems see the CHANGELOG file to find out who contributed 36the specific port. In addition, there are various MAINTAINERS files 37scattered throughout the U-Boot source identifying the people or 38companies responsible for various boards and subsystems. 39 40Note: As of August, 2010, there is no longer a CHANGELOG file in the 41actual U-Boot source tree; however, it can be created dynamically 42from the Git log using: 43 44 make CHANGELOG 45 46 47Where to get help: 48================== 49 50In case you have questions about, problems with or contributions for 51U-Boot, you should send a message to the U-Boot mailing list at 52<u-boot@lists.denx.de>. There is also an archive of previous traffic 53on the mailing list - please search the archive before asking FAQ's. 54Please see http://lists.denx.de/pipermail/u-boot and 55http://dir.gmane.org/gmane.comp.boot-loaders.u-boot 56 57 58Where to get source code: 59========================= 60 61The U-Boot source code is maintained in the Git repository at 62git://www.denx.de/git/u-boot.git ; you can browse it online at 63http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary 64 65The "snapshot" links on this page allow you to download tarballs of 66any version you might be interested in. Official releases are also 67available for FTP download from the ftp://ftp.denx.de/pub/u-boot/ 68directory. 69 70Pre-built (and tested) images are available from 71ftp://ftp.denx.de/pub/u-boot/images/ 72 73 74Where we come from: 75=================== 76 77- start from 8xxrom sources 78- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 79- clean up code 80- make it easier to add custom boards 81- make it possible to add other [PowerPC] CPUs 82- extend functions, especially: 83 * Provide extended interface to Linux boot loader 84 * S-Record download 85 * network boot 86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot 87- create ARMBoot project (http://sourceforge.net/projects/armboot) 88- add other CPU families (starting with ARM) 89- create U-Boot project (http://sourceforge.net/projects/u-boot) 90- current project page: see http://www.denx.de/wiki/U-Boot 91 92 93Names and Spelling: 94=================== 95 96The "official" name of this project is "Das U-Boot". The spelling 97"U-Boot" shall be used in all written text (documentation, comments 98in source files etc.). Example: 99 100 This is the README file for the U-Boot project. 101 102File names etc. shall be based on the string "u-boot". Examples: 103 104 include/asm-ppc/u-boot.h 105 106 #include <asm/u-boot.h> 107 108Variable names, preprocessor constants etc. shall be either based on 109the string "u_boot" or on "U_BOOT". Example: 110 111 U_BOOT_VERSION u_boot_logo 112 IH_OS_U_BOOT u_boot_hush_start 113 114 115Versioning: 116=========== 117 118Starting with the release in October 2008, the names of the releases 119were changed from numerical release numbers without deeper meaning 120into a time stamp based numbering. Regular releases are identified by 121names consisting of the calendar year and month of the release date. 122Additional fields (if present) indicate release candidates or bug fix 123releases in "stable" maintenance trees. 124 125Examples: 126 U-Boot v2009.11 - Release November 2009 127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree 128 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release 129 130 131Directory Hierarchy: 132==================== 133 134/arch Architecture specific files 135 /arc Files generic to ARC architecture 136 /arm Files generic to ARM architecture 137 /m68k Files generic to m68k architecture 138 /microblaze Files generic to microblaze architecture 139 /mips Files generic to MIPS architecture 140 /nds32 Files generic to NDS32 architecture 141 /nios2 Files generic to Altera NIOS2 architecture 142 /openrisc Files generic to OpenRISC architecture 143 /powerpc Files generic to PowerPC architecture 144 /riscv Files generic to RISC-V architecture 145 /sandbox Files generic to HW-independent "sandbox" 146 /sh Files generic to SH architecture 147 /x86 Files generic to x86 architecture 148/api Machine/arch independent API for external apps 149/board Board dependent files 150/cmd U-Boot commands functions 151/common Misc architecture independent functions 152/configs Board default configuration files 153/disk Code for disk drive partition handling 154/doc Documentation (don't expect too much) 155/drivers Commonly used device drivers 156/dts Contains Makefile for building internal U-Boot fdt. 157/examples Example code for standalone applications, etc. 158/fs Filesystem code (cramfs, ext2, jffs2, etc.) 159/include Header Files 160/lib Library routines generic to all architectures 161/Licenses Various license files 162/net Networking code 163/post Power On Self Test 164/scripts Various build scripts and Makefiles 165/test Various unit test files 166/tools Tools to build S-Record or U-Boot images, etc. 167 168Software Configuration: 169======================= 170 171Configuration is usually done using C preprocessor defines; the 172rationale behind that is to avoid dead code whenever possible. 173 174There are two classes of configuration variables: 175 176* Configuration _OPTIONS_: 177 These are selectable by the user and have names beginning with 178 "CONFIG_". 179 180* Configuration _SETTINGS_: 181 These depend on the hardware etc. and should not be meddled with if 182 you don't know what you're doing; they have names beginning with 183 "CONFIG_SYS_". 184 185Previously, all configuration was done by hand, which involved creating 186symbolic links and editing configuration files manually. More recently, 187U-Boot has added the Kbuild infrastructure used by the Linux kernel, 188allowing you to use the "make menuconfig" command to configure your 189build. 190 191 192Selection of Processor Architecture and Board Type: 193--------------------------------------------------- 194 195For all supported boards there are ready-to-use default 196configurations available; just type "make <board_name>_defconfig". 197 198Example: For a TQM823L module type: 199 200 cd u-boot 201 make TQM823L_defconfig 202 203Note: If you're looking for the default configuration file for a board 204you're sure used to be there but is now missing, check the file 205doc/README.scrapyard for a list of no longer supported boards. 206 207Sandbox Environment: 208-------------------- 209 210U-Boot can be built natively to run on a Linux host using the 'sandbox' 211board. This allows feature development which is not board- or architecture- 212specific to be undertaken on a native platform. The sandbox is also used to 213run some of U-Boot's tests. 214 215See board/sandbox/README.sandbox for more details. 216 217 218Board Initialisation Flow: 219-------------------------- 220 221This is the intended start-up flow for boards. This should apply for both 222SPL and U-Boot proper (i.e. they both follow the same rules). 223 224Note: "SPL" stands for "Secondary Program Loader," which is explained in 225more detail later in this file. 226 227At present, SPL mostly uses a separate code path, but the function names 228and roles of each function are the same. Some boards or architectures 229may not conform to this. At least most ARM boards which use 230CONFIG_SPL_FRAMEWORK conform to this. 231 232Execution typically starts with an architecture-specific (and possibly 233CPU-specific) start.S file, such as: 234 235 - arch/arm/cpu/armv7/start.S 236 - arch/powerpc/cpu/mpc83xx/start.S 237 - arch/mips/cpu/start.S 238 239and so on. From there, three functions are called; the purpose and 240limitations of each of these functions are described below. 241 242lowlevel_init(): 243 - purpose: essential init to permit execution to reach board_init_f() 244 - no global_data or BSS 245 - there is no stack (ARMv7 may have one but it will soon be removed) 246 - must not set up SDRAM or use console 247 - must only do the bare minimum to allow execution to continue to 248 board_init_f() 249 - this is almost never needed 250 - return normally from this function 251 252board_init_f(): 253 - purpose: set up the machine ready for running board_init_r(): 254 i.e. SDRAM and serial UART 255 - global_data is available 256 - stack is in SRAM 257 - BSS is not available, so you cannot use global/static variables, 258 only stack variables and global_data 259 260 Non-SPL-specific notes: 261 - dram_init() is called to set up DRAM. If already done in SPL this 262 can do nothing 263 264 SPL-specific notes: 265 - you can override the entire board_init_f() function with your own 266 version as needed. 267 - preloader_console_init() can be called here in extremis 268 - should set up SDRAM, and anything needed to make the UART work 269 - these is no need to clear BSS, it will be done by crt0.S 270 - must return normally from this function (don't call board_init_r() 271 directly) 272 273Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at 274this point the stack and global_data are relocated to below 275CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of 276memory. 277 278board_init_r(): 279 - purpose: main execution, common code 280 - global_data is available 281 - SDRAM is available 282 - BSS is available, all static/global variables can be used 283 - execution eventually continues to main_loop() 284 285 Non-SPL-specific notes: 286 - U-Boot is relocated to the top of memory and is now running from 287 there. 288 289 SPL-specific notes: 290 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and 291 CONFIG_SPL_STACK_R_ADDR points into SDRAM 292 - preloader_console_init() can be called here - typically this is 293 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a 294 spl_board_init() function containing this call 295 - loads U-Boot or (in falcon mode) Linux 296 297 298 299Configuration Options: 300---------------------- 301 302Configuration depends on the combination of board and CPU type; all 303such information is kept in a configuration file 304"include/configs/<board_name>.h". 305 306Example: For a TQM823L module, all configuration settings are in 307"include/configs/TQM823L.h". 308 309 310Many of the options are named exactly as the corresponding Linux 311kernel configuration options. The intention is to make it easier to 312build a config tool - later. 313 314- ARM Platform Bus Type(CCI): 315 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which 316 provides full cache coherency between two clusters of multi-core 317 CPUs and I/O coherency for devices and I/O masters 318 319 CONFIG_SYS_FSL_HAS_CCI400 320 321 Defined For SoC that has cache coherent interconnect 322 CCN-400 323 324 CONFIG_SYS_FSL_HAS_CCN504 325 326 Defined for SoC that has cache coherent interconnect CCN-504 327 328The following options need to be configured: 329 330- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX. 331 332- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS. 333 334- 85xx CPU Options: 335 CONFIG_SYS_PPC64 336 337 Specifies that the core is a 64-bit PowerPC implementation (implements 338 the "64" category of the Power ISA). This is necessary for ePAPR 339 compliance, among other possible reasons. 340 341 CONFIG_SYS_FSL_TBCLK_DIV 342 343 Defines the core time base clock divider ratio compared to the 344 system clock. On most PQ3 devices this is 8, on newer QorIQ 345 devices it can be 16 or 32. The ratio varies from SoC to Soc. 346 347 CONFIG_SYS_FSL_PCIE_COMPAT 348 349 Defines the string to utilize when trying to match PCIe device 350 tree nodes for the given platform. 351 352 CONFIG_SYS_FSL_ERRATUM_A004510 353 354 Enables a workaround for erratum A004510. If set, 355 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and 356 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set. 357 358 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV 359 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional) 360 361 Defines one or two SoC revisions (low 8 bits of SVR) 362 for which the A004510 workaround should be applied. 363 364 The rest of SVR is either not relevant to the decision 365 of whether the erratum is present (e.g. p2040 versus 366 p2041) or is implied by the build target, which controls 367 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set. 368 369 See Freescale App Note 4493 for more information about 370 this erratum. 371 372 CONFIG_A003399_NOR_WORKAROUND 373 Enables a workaround for IFC erratum A003399. It is only 374 required during NOR boot. 375 376 CONFIG_A008044_WORKAROUND 377 Enables a workaround for T1040/T1042 erratum A008044. It is only 378 required during NAND boot and valid for Rev 1.0 SoC revision 379 380 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY 381 382 This is the value to write into CCSR offset 0x18600 383 according to the A004510 workaround. 384 385 CONFIG_SYS_FSL_DSP_DDR_ADDR 386 This value denotes start offset of DDR memory which is 387 connected exclusively to the DSP cores. 388 389 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR 390 This value denotes start offset of M2 memory 391 which is directly connected to the DSP core. 392 393 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR 394 This value denotes start offset of M3 memory which is directly 395 connected to the DSP core. 396 397 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT 398 This value denotes start offset of DSP CCSR space. 399 400 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK 401 Single Source Clock is clocking mode present in some of FSL SoC's. 402 In this mode, a single differential clock is used to supply 403 clocks to the sysclock, ddrclock and usbclock. 404 405 CONFIG_SYS_CPC_REINIT_F 406 This CONFIG is defined when the CPC is configured as SRAM at the 407 time of U-Boot entry and is required to be re-initialized. 408 409 CONFIG_DEEP_SLEEP 410 Indicates this SoC supports deep sleep feature. If deep sleep is 411 supported, core will start to execute uboot when wakes up. 412 413- Generic CPU options: 414 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN 415 416 Defines the endianess of the CPU. Implementation of those 417 values is arch specific. 418 419 CONFIG_SYS_FSL_DDR 420 Freescale DDR driver in use. This type of DDR controller is 421 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core 422 SoCs. 423 424 CONFIG_SYS_FSL_DDR_ADDR 425 Freescale DDR memory-mapped register base. 426 427 CONFIG_SYS_FSL_DDR_EMU 428 Specify emulator support for DDR. Some DDR features such as 429 deskew training are not available. 430 431 CONFIG_SYS_FSL_DDRC_GEN1 432 Freescale DDR1 controller. 433 434 CONFIG_SYS_FSL_DDRC_GEN2 435 Freescale DDR2 controller. 436 437 CONFIG_SYS_FSL_DDRC_GEN3 438 Freescale DDR3 controller. 439 440 CONFIG_SYS_FSL_DDRC_GEN4 441 Freescale DDR4 controller. 442 443 CONFIG_SYS_FSL_DDRC_ARM_GEN3 444 Freescale DDR3 controller for ARM-based SoCs. 445 446 CONFIG_SYS_FSL_DDR1 447 Board config to use DDR1. It can be enabled for SoCs with 448 Freescale DDR1 or DDR2 controllers, depending on the board 449 implemetation. 450 451 CONFIG_SYS_FSL_DDR2 452 Board config to use DDR2. It can be enabled for SoCs with 453 Freescale DDR2 or DDR3 controllers, depending on the board 454 implementation. 455 456 CONFIG_SYS_FSL_DDR3 457 Board config to use DDR3. It can be enabled for SoCs with 458 Freescale DDR3 or DDR3L controllers. 459 460 CONFIG_SYS_FSL_DDR3L 461 Board config to use DDR3L. It can be enabled for SoCs with 462 DDR3L controllers. 463 464 CONFIG_SYS_FSL_DDR4 465 Board config to use DDR4. It can be enabled for SoCs with 466 DDR4 controllers. 467 468 CONFIG_SYS_FSL_IFC_BE 469 Defines the IFC controller register space as Big Endian 470 471 CONFIG_SYS_FSL_IFC_LE 472 Defines the IFC controller register space as Little Endian 473 474 CONFIG_SYS_FSL_IFC_CLK_DIV 475 Defines divider of platform clock(clock input to IFC controller). 476 477 CONFIG_SYS_FSL_LBC_CLK_DIV 478 Defines divider of platform clock(clock input to eLBC controller). 479 480 CONFIG_SYS_FSL_PBL_PBI 481 It enables addition of RCW (Power on reset configuration) in built image. 482 Please refer doc/README.pblimage for more details 483 484 CONFIG_SYS_FSL_PBL_RCW 485 It adds PBI(pre-boot instructions) commands in u-boot build image. 486 PBI commands can be used to configure SoC before it starts the execution. 487 Please refer doc/README.pblimage for more details 488 489 CONFIG_SPL_FSL_PBL 490 It adds a target to create boot binary having SPL binary in PBI format 491 concatenated with u-boot binary. 492 493 CONFIG_SYS_FSL_DDR_BE 494 Defines the DDR controller register space as Big Endian 495 496 CONFIG_SYS_FSL_DDR_LE 497 Defines the DDR controller register space as Little Endian 498 499 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY 500 Physical address from the view of DDR controllers. It is the 501 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But 502 it could be different for ARM SoCs. 503 504 CONFIG_SYS_FSL_DDR_INTLV_256B 505 DDR controller interleaving on 256-byte. This is a special 506 interleaving mode, handled by Dickens for Freescale layerscape 507 SoCs with ARM core. 508 509 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS 510 Number of controllers used as main memory. 511 512 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS 513 Number of controllers used for other than main memory. 514 515 CONFIG_SYS_FSL_HAS_DP_DDR 516 Defines the SoC has DP-DDR used for DPAA. 517 518 CONFIG_SYS_FSL_SEC_BE 519 Defines the SEC controller register space as Big Endian 520 521 CONFIG_SYS_FSL_SEC_LE 522 Defines the SEC controller register space as Little Endian 523 524- MIPS CPU options: 525 CONFIG_SYS_INIT_SP_OFFSET 526 527 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack 528 pointer. This is needed for the temporary stack before 529 relocation. 530 531 CONFIG_SYS_MIPS_CACHE_MODE 532 533 Cache operation mode for the MIPS CPU. 534 See also arch/mips/include/asm/mipsregs.h. 535 Possible values are: 536 CONF_CM_CACHABLE_NO_WA 537 CONF_CM_CACHABLE_WA 538 CONF_CM_UNCACHED 539 CONF_CM_CACHABLE_NONCOHERENT 540 CONF_CM_CACHABLE_CE 541 CONF_CM_CACHABLE_COW 542 CONF_CM_CACHABLE_CUW 543 CONF_CM_CACHABLE_ACCELERATED 544 545 CONFIG_SYS_XWAY_EBU_BOOTCFG 546 547 Special option for Lantiq XWAY SoCs for booting from NOR flash. 548 See also arch/mips/cpu/mips32/start.S. 549 550 CONFIG_XWAY_SWAP_BYTES 551 552 Enable compilation of tools/xway-swap-bytes needed for Lantiq 553 XWAY SoCs for booting from NOR flash. The U-Boot image needs to 554 be swapped if a flash programmer is used. 555 556- ARM options: 557 CONFIG_SYS_EXCEPTION_VECTORS_HIGH 558 559 Select high exception vectors of the ARM core, e.g., do not 560 clear the V bit of the c1 register of CP15. 561 562 COUNTER_FREQUENCY 563 Generic timer clock source frequency. 564 565 COUNTER_FREQUENCY_REAL 566 Generic timer clock source frequency if the real clock is 567 different from COUNTER_FREQUENCY, and can only be determined 568 at run time. 569 570- Tegra SoC options: 571 CONFIG_TEGRA_SUPPORT_NON_SECURE 572 573 Support executing U-Boot in non-secure (NS) mode. Certain 574 impossible actions will be skipped if the CPU is in NS mode, 575 such as ARM architectural timer initialization. 576 577- Linux Kernel Interface: 578 CONFIG_CLOCKS_IN_MHZ 579 580 U-Boot stores all clock information in Hz 581 internally. For binary compatibility with older Linux 582 kernels (which expect the clocks passed in the 583 bd_info data to be in MHz) the environment variable 584 "clocks_in_mhz" can be defined so that U-Boot 585 converts clock data to MHZ before passing it to the 586 Linux kernel. 587 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 588 "clocks_in_mhz=1" is automatically included in the 589 default environment. 590 591 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 592 593 When transferring memsize parameter to Linux, some versions 594 expect it to be in bytes, others in MB. 595 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 596 597 CONFIG_OF_LIBFDT 598 599 New kernel versions are expecting firmware settings to be 600 passed using flattened device trees (based on open firmware 601 concepts). 602 603 CONFIG_OF_LIBFDT 604 * New libfdt-based support 605 * Adds the "fdt" command 606 * The bootm command automatically updates the fdt 607 608 OF_TBCLK - The timebase frequency. 609 OF_STDOUT_PATH - The path to the console device 610 611 boards with QUICC Engines require OF_QE to set UCC MAC 612 addresses 613 614 CONFIG_OF_BOARD_SETUP 615 616 Board code has addition modification that it wants to make 617 to the flat device tree before handing it off to the kernel 618 619 CONFIG_OF_SYSTEM_SETUP 620 621 Other code has addition modification that it wants to make 622 to the flat device tree before handing it off to the kernel. 623 This causes ft_system_setup() to be called before booting 624 the kernel. 625 626 CONFIG_OF_IDE_FIXUP 627 628 U-Boot can detect if an IDE device is present or not. 629 If not, and this new config option is activated, U-Boot 630 removes the ATA node from the DTS before booting Linux, 631 so the Linux IDE driver does not probe the device and 632 crash. This is needed for buggy hardware (uc101) where 633 no pull down resistor is connected to the signal IDE5V_DD7. 634 635 CONFIG_MACH_TYPE [relevant for ARM only][mandatory] 636 637 This setting is mandatory for all boards that have only one 638 machine type and must be used to specify the machine type 639 number as it appears in the ARM machine registry 640 (see http://www.arm.linux.org.uk/developer/machines/). 641 Only boards that have multiple machine types supported 642 in a single configuration file and the machine type is 643 runtime discoverable, do not have to use this setting. 644 645- vxWorks boot parameters: 646 647 bootvx constructs a valid bootline using the following 648 environments variables: bootdev, bootfile, ipaddr, netmask, 649 serverip, gatewayip, hostname, othbootargs. 650 It loads the vxWorks image pointed bootfile. 651 652 Note: If a "bootargs" environment is defined, it will overwride 653 the defaults discussed just above. 654 655- Cache Configuration: 656 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot 657 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot 658 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot 659 660- Cache Configuration for ARM: 661 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache 662 controller 663 CONFIG_SYS_PL310_BASE - Physical base address of PL310 664 controller register space 665 666- Serial Ports: 667 CONFIG_PL010_SERIAL 668 669 Define this if you want support for Amba PrimeCell PL010 UARTs. 670 671 CONFIG_PL011_SERIAL 672 673 Define this if you want support for Amba PrimeCell PL011 UARTs. 674 675 CONFIG_PL011_CLOCK 676 677 If you have Amba PrimeCell PL011 UARTs, set this variable to 678 the clock speed of the UARTs. 679 680 CONFIG_PL01x_PORTS 681 682 If you have Amba PrimeCell PL010 or PL011 UARTs on your board, 683 define this to a list of base addresses for each (supported) 684 port. See e.g. include/configs/versatile.h 685 686 CONFIG_SERIAL_HW_FLOW_CONTROL 687 688 Define this variable to enable hw flow control in serial driver. 689 Current user of this option is drivers/serial/nsl16550.c driver 690 691- Console Baudrate: 692 CONFIG_BAUDRATE - in bps 693 Select one of the baudrates listed in 694 CONFIG_SYS_BAUDRATE_TABLE, see below. 695 696- Autoboot Command: 697 CONFIG_BOOTCOMMAND 698 Only needed when CONFIG_BOOTDELAY is enabled; 699 define a command string that is automatically executed 700 when no character is read on the console interface 701 within "Boot Delay" after reset. 702 703 CONFIG_RAMBOOT and CONFIG_NFSBOOT 704 The value of these goes into the environment as 705 "ramboot" and "nfsboot" respectively, and can be used 706 as a convenience, when switching between booting from 707 RAM and NFS. 708 709- Pre-Boot Commands: 710 CONFIG_PREBOOT 711 712 When this option is #defined, the existence of the 713 environment variable "preboot" will be checked 714 immediately before starting the CONFIG_BOOTDELAY 715 countdown and/or running the auto-boot command resp. 716 entering interactive mode. 717 718 This feature is especially useful when "preboot" is 719 automatically generated or modified. For an example 720 see the LWMON board specific code: here "preboot" is 721 modified when the user holds down a certain 722 combination of keys on the (special) keyboard when 723 booting the systems 724 725- Serial Download Echo Mode: 726 CONFIG_LOADS_ECHO 727 If defined to 1, all characters received during a 728 serial download (using the "loads" command) are 729 echoed back. This might be needed by some terminal 730 emulations (like "cu"), but may as well just take 731 time on others. This setting #define's the initial 732 value of the "loads_echo" environment variable. 733 734- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined) 735 CONFIG_KGDB_BAUDRATE 736 Select one of the baudrates listed in 737 CONFIG_SYS_BAUDRATE_TABLE, see below. 738 739- Removal of commands 740 If no commands are needed to boot, you can disable 741 CONFIG_CMDLINE to remove them. In this case, the command line 742 will not be available, and when U-Boot wants to execute the 743 boot command (on start-up) it will call board_run_command() 744 instead. This can reduce image size significantly for very 745 simple boot procedures. 746 747- Regular expression support: 748 CONFIG_REGEX 749 If this variable is defined, U-Boot is linked against 750 the SLRE (Super Light Regular Expression) library, 751 which adds regex support to some commands, as for 752 example "env grep" and "setexpr". 753 754- Device tree: 755 CONFIG_OF_CONTROL 756 If this variable is defined, U-Boot will use a device tree 757 to configure its devices, instead of relying on statically 758 compiled #defines in the board file. This option is 759 experimental and only available on a few boards. The device 760 tree is available in the global data as gd->fdt_blob. 761 762 U-Boot needs to get its device tree from somewhere. This can 763 be done using one of the three options below: 764 765 CONFIG_OF_EMBED 766 If this variable is defined, U-Boot will embed a device tree 767 binary in its image. This device tree file should be in the 768 board directory and called <soc>-<board>.dts. The binary file 769 is then picked up in board_init_f() and made available through 770 the global data structure as gd->fdt_blob. 771 772 CONFIG_OF_SEPARATE 773 If this variable is defined, U-Boot will build a device tree 774 binary. It will be called u-boot.dtb. Architecture-specific 775 code will locate it at run-time. Generally this works by: 776 777 cat u-boot.bin u-boot.dtb >image.bin 778 779 and in fact, U-Boot does this for you, creating a file called 780 u-boot-dtb.bin which is useful in the common case. You can 781 still use the individual files if you need something more 782 exotic. 783 784 CONFIG_OF_BOARD 785 If this variable is defined, U-Boot will use the device tree 786 provided by the board at runtime instead of embedding one with 787 the image. Only boards defining board_fdt_blob_setup() support 788 this option (see include/fdtdec.h file). 789 790- Watchdog: 791 CONFIG_WATCHDOG 792 If this variable is defined, it enables watchdog 793 support for the SoC. There must be support in the SoC 794 specific code for a watchdog. For the 8xx 795 CPUs, the SIU Watchdog feature is enabled in the SYPCR 796 register. When supported for a specific SoC is 797 available, then no further board specific code should 798 be needed to use it. 799 800 CONFIG_HW_WATCHDOG 801 When using a watchdog circuitry external to the used 802 SoC, then define this variable and provide board 803 specific code for the "hw_watchdog_reset" function. 804 805 CONFIG_AT91_HW_WDT_TIMEOUT 806 specify the timeout in seconds. default 2 seconds. 807 808- Real-Time Clock: 809 810 When CONFIG_CMD_DATE is selected, the type of the RTC 811 has to be selected, too. Define exactly one of the 812 following options: 813 814 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 815 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC 816 CONFIG_RTC_MC146818 - use MC146818 RTC 817 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 818 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 819 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 820 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC 821 CONFIG_RTC_DS164x - use Dallas DS164x RTC 822 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC 823 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 824 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337 825 CONFIG_SYS_RV3029_TCR - enable trickle charger on 826 RV3029 RTC. 827 828 Note that if the RTC uses I2C, then the I2C interface 829 must also be configured. See I2C Support, below. 830 831- GPIO Support: 832 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO 833 834 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of 835 chip-ngpio pairs that tell the PCA953X driver the number of 836 pins supported by a particular chip. 837 838 Note that if the GPIO device uses I2C, then the I2C interface 839 must also be configured. See I2C Support, below. 840 841- I/O tracing: 842 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O 843 accesses and can checksum them or write a list of them out 844 to memory. See the 'iotrace' command for details. This is 845 useful for testing device drivers since it can confirm that 846 the driver behaves the same way before and after a code 847 change. Currently this is supported on sandbox and arm. To 848 add support for your architecture, add '#include <iotrace.h>' 849 to the bottom of arch/<arch>/include/asm/io.h and test. 850 851 Example output from the 'iotrace stats' command is below. 852 Note that if the trace buffer is exhausted, the checksum will 853 still continue to operate. 854 855 iotrace is enabled 856 Start: 10000000 (buffer start address) 857 Size: 00010000 (buffer size) 858 Offset: 00000120 (current buffer offset) 859 Output: 10000120 (start + offset) 860 Count: 00000018 (number of trace records) 861 CRC32: 9526fb66 (CRC32 of all trace records) 862 863- Timestamp Support: 864 865 When CONFIG_TIMESTAMP is selected, the timestamp 866 (date and time) of an image is printed by image 867 commands like bootm or iminfo. This option is 868 automatically enabled when you select CONFIG_CMD_DATE . 869 870- Partition Labels (disklabels) Supported: 871 Zero or more of the following: 872 CONFIG_MAC_PARTITION Apple's MacOS partition table. 873 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc. 874 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the 875 bootloader. Note 2TB partition limit; see 876 disk/part_efi.c 877 CONFIG_SCSI) you must configure support for at 878 least one non-MTD partition type as well. 879 880- IDE Reset method: 881 CONFIG_IDE_RESET_ROUTINE - this is defined in several 882 board configurations files but used nowhere! 883 884 CONFIG_IDE_RESET - is this is defined, IDE Reset will 885 be performed by calling the function 886 ide_set_reset(int reset) 887 which has to be defined in a board specific file 888 889- ATAPI Support: 890 CONFIG_ATAPI 891 892 Set this to enable ATAPI support. 893 894- LBA48 Support 895 CONFIG_LBA48 896 897 Set this to enable support for disks larger than 137GB 898 Also look at CONFIG_SYS_64BIT_LBA. 899 Whithout these , LBA48 support uses 32bit variables and will 'only' 900 support disks up to 2.1TB. 901 902 CONFIG_SYS_64BIT_LBA: 903 When enabled, makes the IDE subsystem use 64bit sector addresses. 904 Default is 32bit. 905 906- SCSI Support: 907 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and 908 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID * 909 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the 910 maximum numbers of LUNs, SCSI ID's and target 911 devices. 912 913 The environment variable 'scsidevs' is set to the number of 914 SCSI devices found during the last scan. 915 916- NETWORK Support (PCI): 917 CONFIG_E1000 918 Support for Intel 8254x/8257x gigabit chips. 919 920 CONFIG_E1000_SPI 921 Utility code for direct access to the SPI bus on Intel 8257x. 922 This does not do anything useful unless you set at least one 923 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC. 924 925 CONFIG_E1000_SPI_GENERIC 926 Allow generic access to the SPI bus on the Intel 8257x, for 927 example with the "sspi" command. 928 929 CONFIG_EEPRO100 930 Support for Intel 82557/82559/82559ER chips. 931 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM 932 write routine for first time initialisation. 933 934 CONFIG_TULIP 935 Support for Digital 2114x chips. 936 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 937 modem chip initialisation (KS8761/QS6611). 938 939 CONFIG_NATSEMI 940 Support for National dp83815 chips. 941 942 CONFIG_NS8382X 943 Support for National dp8382[01] gigabit chips. 944 945- NETWORK Support (other): 946 947 CONFIG_DRIVER_AT91EMAC 948 Support for AT91RM9200 EMAC. 949 950 CONFIG_RMII 951 Define this to use reduced MII inteface 952 953 CONFIG_DRIVER_AT91EMAC_QUIET 954 If this defined, the driver is quiet. 955 The driver doen't show link status messages. 956 957 CONFIG_CALXEDA_XGMAC 958 Support for the Calxeda XGMAC device 959 960 CONFIG_LAN91C96 961 Support for SMSC's LAN91C96 chips. 962 963 CONFIG_LAN91C96_USE_32_BIT 964 Define this to enable 32 bit addressing 965 966 CONFIG_SMC91111 967 Support for SMSC's LAN91C111 chip 968 969 CONFIG_SMC91111_BASE 970 Define this to hold the physical address 971 of the device (I/O space) 972 973 CONFIG_SMC_USE_32_BIT 974 Define this if data bus is 32 bits 975 976 CONFIG_SMC_USE_IOFUNCS 977 Define this to use i/o functions instead of macros 978 (some hardware wont work with macros) 979 980 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 981 Define this if you have more then 3 PHYs. 982 983 CONFIG_FTGMAC100 984 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 985 986 CONFIG_FTGMAC100_EGIGA 987 Define this to use GE link update with gigabit PHY. 988 Define this if FTGMAC100 is connected to gigabit PHY. 989 If your system has 10/100 PHY only, it might not occur 990 wrong behavior. Because PHY usually return timeout or 991 useless data when polling gigabit status and gigabit 992 control registers. This behavior won't affect the 993 correctnessof 10/100 link speed update. 994 995 CONFIG_SH_ETHER 996 Support for Renesas on-chip Ethernet controller 997 998 CONFIG_SH_ETHER_USE_PORT 999 Define the number of ports to be used 1000 1001 CONFIG_SH_ETHER_PHY_ADDR 1002 Define the ETH PHY's address 1003 1004 CONFIG_SH_ETHER_CACHE_WRITEBACK 1005 If this option is set, the driver enables cache flush. 1006 1007- PWM Support: 1008 CONFIG_PWM_IMX 1009 Support for PWM module on the imx6. 1010 1011- TPM Support: 1012 CONFIG_TPM 1013 Support TPM devices. 1014 1015 CONFIG_TPM_TIS_INFINEON 1016 Support for Infineon i2c bus TPM devices. Only one device 1017 per system is supported at this time. 1018 1019 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 1020 Define the burst count bytes upper limit 1021 1022 CONFIG_TPM_ST33ZP24 1023 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 1024 1025 CONFIG_TPM_ST33ZP24_I2C 1026 Support for STMicroelectronics ST33ZP24 I2C devices. 1027 Requires TPM_ST33ZP24 and I2C. 1028 1029 CONFIG_TPM_ST33ZP24_SPI 1030 Support for STMicroelectronics ST33ZP24 SPI devices. 1031 Requires TPM_ST33ZP24 and SPI. 1032 1033 CONFIG_TPM_ATMEL_TWI 1034 Support for Atmel TWI TPM device. Requires I2C support. 1035 1036 CONFIG_TPM_TIS_LPC 1037 Support for generic parallel port TPM devices. Only one device 1038 per system is supported at this time. 1039 1040 CONFIG_TPM_TIS_BASE_ADDRESS 1041 Base address where the generic TPM device is mapped 1042 to. Contemporary x86 systems usually map it at 1043 0xfed40000. 1044 1045 CONFIG_TPM 1046 Define this to enable the TPM support library which provides 1047 functional interfaces to some TPM commands. 1048 Requires support for a TPM device. 1049 1050 CONFIG_TPM_AUTH_SESSIONS 1051 Define this to enable authorized functions in the TPM library. 1052 Requires CONFIG_TPM and CONFIG_SHA1. 1053 1054- USB Support: 1055 At the moment only the UHCI host controller is 1056 supported (PIP405, MIP405); define 1057 CONFIG_USB_UHCI to enable it. 1058 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 1059 and define CONFIG_USB_STORAGE to enable the USB 1060 storage devices. 1061 Note: 1062 Supported are USB Keyboards and USB Floppy drives 1063 (TEAC FD-05PUB). 1064 1065 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 1066 txfilltuning field in the EHCI controller on reset. 1067 1068 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2 1069 HW module registers. 1070 1071- USB Device: 1072 Define the below if you wish to use the USB console. 1073 Once firmware is rebuilt from a serial console issue the 1074 command "setenv stdin usbtty; setenv stdout usbtty" and 1075 attach your USB cable. The Unix command "dmesg" should print 1076 it has found a new device. The environment variable usbtty 1077 can be set to gserial or cdc_acm to enable your device to 1078 appear to a USB host as a Linux gserial device or a 1079 Common Device Class Abstract Control Model serial device. 1080 If you select usbtty = gserial you should be able to enumerate 1081 a Linux host by 1082 # modprobe usbserial vendor=0xVendorID product=0xProductID 1083 else if using cdc_acm, simply setting the environment 1084 variable usbtty to be cdc_acm should suffice. The following 1085 might be defined in YourBoardName.h 1086 1087 CONFIG_USB_DEVICE 1088 Define this to build a UDC device 1089 1090 CONFIG_USB_TTY 1091 Define this to have a tty type of device available to 1092 talk to the UDC device 1093 1094 CONFIG_USBD_HS 1095 Define this to enable the high speed support for usb 1096 device and usbtty. If this feature is enabled, a routine 1097 int is_usbd_high_speed(void) 1098 also needs to be defined by the driver to dynamically poll 1099 whether the enumeration has succeded at high speed or full 1100 speed. 1101 1102 CONFIG_SYS_CONSOLE_IS_IN_ENV 1103 Define this if you want stdin, stdout &/or stderr to 1104 be set to usbtty. 1105 1106 If you have a USB-IF assigned VendorID then you may wish to 1107 define your own vendor specific values either in BoardName.h 1108 or directly in usbd_vendor_info.h. If you don't define 1109 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 1110 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 1111 should pretend to be a Linux device to it's target host. 1112 1113 CONFIG_USBD_MANUFACTURER 1114 Define this string as the name of your company for 1115 - CONFIG_USBD_MANUFACTURER "my company" 1116 1117 CONFIG_USBD_PRODUCT_NAME 1118 Define this string as the name of your product 1119 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 1120 1121 CONFIG_USBD_VENDORID 1122 Define this as your assigned Vendor ID from the USB 1123 Implementors Forum. This *must* be a genuine Vendor ID 1124 to avoid polluting the USB namespace. 1125 - CONFIG_USBD_VENDORID 0xFFFF 1126 1127 CONFIG_USBD_PRODUCTID 1128 Define this as the unique Product ID 1129 for your device 1130 - CONFIG_USBD_PRODUCTID 0xFFFF 1131 1132- ULPI Layer Support: 1133 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 1134 the generic ULPI layer. The generic layer accesses the ULPI PHY 1135 via the platform viewport, so you need both the genric layer and 1136 the viewport enabled. Currently only Chipidea/ARC based 1137 viewport is supported. 1138 To enable the ULPI layer support, define CONFIG_USB_ULPI and 1139 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 1140 If your ULPI phy needs a different reference clock than the 1141 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 1142 the appropriate value in Hz. 1143 1144- MMC Support: 1145 The MMC controller on the Intel PXA is supported. To 1146 enable this define CONFIG_MMC. The MMC can be 1147 accessed from the boot prompt by mapping the device 1148 to physical memory similar to flash. Command line is 1149 enabled with CONFIG_CMD_MMC. The MMC driver also works with 1150 the FAT fs. This is enabled with CONFIG_CMD_FAT. 1151 1152 CONFIG_SH_MMCIF 1153 Support for Renesas on-chip MMCIF controller 1154 1155 CONFIG_SH_MMCIF_ADDR 1156 Define the base address of MMCIF registers 1157 1158 CONFIG_SH_MMCIF_CLK 1159 Define the clock frequency for MMCIF 1160 1161 CONFIG_SUPPORT_EMMC_BOOT 1162 Enable some additional features of the eMMC boot partitions. 1163 1164- USB Device Firmware Update (DFU) class support: 1165 CONFIG_DFU_OVER_USB 1166 This enables the USB portion of the DFU USB class 1167 1168 CONFIG_DFU_MMC 1169 This enables support for exposing (e)MMC devices via DFU. 1170 1171 CONFIG_DFU_NAND 1172 This enables support for exposing NAND devices via DFU. 1173 1174 CONFIG_DFU_RAM 1175 This enables support for exposing RAM via DFU. 1176 Note: DFU spec refer to non-volatile memory usage, but 1177 allow usages beyond the scope of spec - here RAM usage, 1178 one that would help mostly the developer. 1179 1180 CONFIG_SYS_DFU_DATA_BUF_SIZE 1181 Dfu transfer uses a buffer before writing data to the 1182 raw storage device. Make the size (in bytes) of this buffer 1183 configurable. The size of this buffer is also configurable 1184 through the "dfu_bufsiz" environment variable. 1185 1186 CONFIG_SYS_DFU_MAX_FILE_SIZE 1187 When updating files rather than the raw storage device, 1188 we use a static buffer to copy the file into and then write 1189 the buffer once we've been given the whole file. Define 1190 this to the maximum filesize (in bytes) for the buffer. 1191 Default is 4 MiB if undefined. 1192 1193 DFU_DEFAULT_POLL_TIMEOUT 1194 Poll timeout [ms], is the timeout a device can send to the 1195 host. The host must wait for this timeout before sending 1196 a subsequent DFU_GET_STATUS request to the device. 1197 1198 DFU_MANIFEST_POLL_TIMEOUT 1199 Poll timeout [ms], which the device sends to the host when 1200 entering dfuMANIFEST state. Host waits this timeout, before 1201 sending again an USB request to the device. 1202 1203- Journaling Flash filesystem support: 1204 CONFIG_JFFS2_NAND 1205 Define these for a default partition on a NAND device 1206 1207 CONFIG_SYS_JFFS2_FIRST_SECTOR, 1208 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 1209 Define these for a default partition on a NOR device 1210 1211- Keyboard Support: 1212 See Kconfig help for available keyboard drivers. 1213 1214 CONFIG_KEYBOARD 1215 1216 Define this to enable a custom keyboard support. 1217 This simply calls drv_keyboard_init() which must be 1218 defined in your board-specific files. This option is deprecated 1219 and is only used by novena. For new boards, use driver model 1220 instead. 1221 1222- Video support: 1223 CONFIG_FSL_DIU_FB 1224 Enable the Freescale DIU video driver. Reference boards for 1225 SOCs that have a DIU should define this macro to enable DIU 1226 support, and should also define these other macros: 1227 1228 CONFIG_SYS_DIU_ADDR 1229 CONFIG_VIDEO 1230 CONFIG_CFB_CONSOLE 1231 CONFIG_VIDEO_SW_CURSOR 1232 CONFIG_VGA_AS_SINGLE_DEVICE 1233 CONFIG_VIDEO_LOGO 1234 CONFIG_VIDEO_BMP_LOGO 1235 1236 The DIU driver will look for the 'video-mode' environment 1237 variable, and if defined, enable the DIU as a console during 1238 boot. See the documentation file doc/README.video for a 1239 description of this variable. 1240 1241- LCD Support: CONFIG_LCD 1242 1243 Define this to enable LCD support (for output to LCD 1244 display); also select one of the supported displays 1245 by defining one of these: 1246 1247 CONFIG_ATMEL_LCD: 1248 1249 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1250 1251 CONFIG_NEC_NL6448AC33: 1252 1253 NEC NL6448AC33-18. Active, color, single scan. 1254 1255 CONFIG_NEC_NL6448BC20 1256 1257 NEC NL6448BC20-08. 6.5", 640x480. 1258 Active, color, single scan. 1259 1260 CONFIG_NEC_NL6448BC33_54 1261 1262 NEC NL6448BC33-54. 10.4", 640x480. 1263 Active, color, single scan. 1264 1265 CONFIG_SHARP_16x9 1266 1267 Sharp 320x240. Active, color, single scan. 1268 It isn't 16x9, and I am not sure what it is. 1269 1270 CONFIG_SHARP_LQ64D341 1271 1272 Sharp LQ64D341 display, 640x480. 1273 Active, color, single scan. 1274 1275 CONFIG_HLD1045 1276 1277 HLD1045 display, 640x480. 1278 Active, color, single scan. 1279 1280 CONFIG_OPTREX_BW 1281 1282 Optrex CBL50840-2 NF-FW 99 22 M5 1283 or 1284 Hitachi LMG6912RPFC-00T 1285 or 1286 Hitachi SP14Q002 1287 1288 320x240. Black & white. 1289 1290 CONFIG_LCD_ALIGNMENT 1291 1292 Normally the LCD is page-aligned (typically 4KB). If this is 1293 defined then the LCD will be aligned to this value instead. 1294 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1295 here, since it is cheaper to change data cache settings on 1296 a per-section basis. 1297 1298 1299 CONFIG_LCD_ROTATION 1300 1301 Sometimes, for example if the display is mounted in portrait 1302 mode or even if it's mounted landscape but rotated by 180degree, 1303 we need to rotate our content of the display relative to the 1304 framebuffer, so that user can read the messages which are 1305 printed out. 1306 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1307 initialized with a given rotation from "vl_rot" out of 1308 "vidinfo_t" which is provided by the board specific code. 1309 The value for vl_rot is coded as following (matching to 1310 fbcon=rotate:<n> linux-kernel commandline): 1311 0 = no rotation respectively 0 degree 1312 1 = 90 degree rotation 1313 2 = 180 degree rotation 1314 3 = 270 degree rotation 1315 1316 If CONFIG_LCD_ROTATION is not defined, the console will be 1317 initialized with 0degree rotation. 1318 1319 CONFIG_LCD_BMP_RLE8 1320 1321 Support drawing of RLE8-compressed bitmaps on the LCD. 1322 1323 CONFIG_I2C_EDID 1324 1325 Enables an 'i2c edid' command which can read EDID 1326 information over I2C from an attached LCD display. 1327 1328- Splash Screen Support: CONFIG_SPLASH_SCREEN 1329 1330 If this option is set, the environment is checked for 1331 a variable "splashimage". If found, the usual display 1332 of logo, copyright and system information on the LCD 1333 is suppressed and the BMP image at the address 1334 specified in "splashimage" is loaded instead. The 1335 console is redirected to the "nulldev", too. This 1336 allows for a "silent" boot where a splash screen is 1337 loaded very quickly after power-on. 1338 1339 CONFIG_SPLASHIMAGE_GUARD 1340 1341 If this option is set, then U-Boot will prevent the environment 1342 variable "splashimage" from being set to a problematic address 1343 (see doc/README.displaying-bmps). 1344 This option is useful for targets where, due to alignment 1345 restrictions, an improperly aligned BMP image will cause a data 1346 abort. If you think you will not have problems with unaligned 1347 accesses (for example because your toolchain prevents them) 1348 there is no need to set this option. 1349 1350 CONFIG_SPLASH_SCREEN_ALIGN 1351 1352 If this option is set the splash image can be freely positioned 1353 on the screen. Environment variable "splashpos" specifies the 1354 position as "x,y". If a positive number is given it is used as 1355 number of pixel from left/top. If a negative number is given it 1356 is used as number of pixel from right/bottom. You can also 1357 specify 'm' for centering the image. 1358 1359 Example: 1360 setenv splashpos m,m 1361 => image at center of screen 1362 1363 setenv splashpos 30,20 1364 => image at x = 30 and y = 20 1365 1366 setenv splashpos -10,m 1367 => vertically centered image 1368 at x = dspWidth - bmpWidth - 9 1369 1370- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP 1371 1372 If this option is set, additionally to standard BMP 1373 images, gzipped BMP images can be displayed via the 1374 splashscreen support or the bmp command. 1375 1376- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8 1377 1378 If this option is set, 8-bit RLE compressed BMP images 1379 can be displayed via the splashscreen support or the 1380 bmp command. 1381 1382- Compression support: 1383 CONFIG_GZIP 1384 1385 Enabled by default to support gzip compressed images. 1386 1387 CONFIG_BZIP2 1388 1389 If this option is set, support for bzip2 compressed 1390 images is included. If not, only uncompressed and gzip 1391 compressed images are supported. 1392 1393 NOTE: the bzip2 algorithm requires a lot of RAM, so 1394 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should 1395 be at least 4MB. 1396 1397- MII/PHY support: 1398 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1399 1400 The clock frequency of the MII bus 1401 1402 CONFIG_PHY_RESET_DELAY 1403 1404 Some PHY like Intel LXT971A need extra delay after 1405 reset before any MII register access is possible. 1406 For such PHY, set this option to the usec delay 1407 required. (minimum 300usec for LXT971A) 1408 1409 CONFIG_PHY_CMD_DELAY (ppc4xx) 1410 1411 Some PHY like Intel LXT971A need extra delay after 1412 command issued before MII status register can be read 1413 1414- IP address: 1415 CONFIG_IPADDR 1416 1417 Define a default value for the IP address to use for 1418 the default Ethernet interface, in case this is not 1419 determined through e.g. bootp. 1420 (Environment variable "ipaddr") 1421 1422- Server IP address: 1423 CONFIG_SERVERIP 1424 1425 Defines a default value for the IP address of a TFTP 1426 server to contact when using the "tftboot" command. 1427 (Environment variable "serverip") 1428 1429 CONFIG_KEEP_SERVERADDR 1430 1431 Keeps the server's MAC address, in the env 'serveraddr' 1432 for passing to bootargs (like Linux's netconsole option) 1433 1434- Gateway IP address: 1435 CONFIG_GATEWAYIP 1436 1437 Defines a default value for the IP address of the 1438 default router where packets to other networks are 1439 sent to. 1440 (Environment variable "gatewayip") 1441 1442- Subnet mask: 1443 CONFIG_NETMASK 1444 1445 Defines a default value for the subnet mask (or 1446 routing prefix) which is used to determine if an IP 1447 address belongs to the local subnet or needs to be 1448 forwarded through a router. 1449 (Environment variable "netmask") 1450 1451- Multicast TFTP Mode: 1452 CONFIG_MCAST_TFTP 1453 1454 Defines whether you want to support multicast TFTP as per 1455 rfc-2090; for example to work with atftp. Lets lots of targets 1456 tftp down the same boot image concurrently. Note: the Ethernet 1457 driver in use must provide a function: mcast() to join/leave a 1458 multicast group. 1459 1460- BOOTP Recovery Mode: 1461 CONFIG_BOOTP_RANDOM_DELAY 1462 1463 If you have many targets in a network that try to 1464 boot using BOOTP, you may want to avoid that all 1465 systems send out BOOTP requests at precisely the same 1466 moment (which would happen for instance at recovery 1467 from a power failure, when all systems will try to 1468 boot, thus flooding the BOOTP server. Defining 1469 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1470 inserted before sending out BOOTP requests. The 1471 following delays are inserted then: 1472 1473 1st BOOTP request: delay 0 ... 1 sec 1474 2nd BOOTP request: delay 0 ... 2 sec 1475 3rd BOOTP request: delay 0 ... 4 sec 1476 4th and following 1477 BOOTP requests: delay 0 ... 8 sec 1478 1479 CONFIG_BOOTP_ID_CACHE_SIZE 1480 1481 BOOTP packets are uniquely identified using a 32-bit ID. The 1482 server will copy the ID from client requests to responses and 1483 U-Boot will use this to determine if it is the destination of 1484 an incoming response. Some servers will check that addresses 1485 aren't in use before handing them out (usually using an ARP 1486 ping) and therefore take up to a few hundred milliseconds to 1487 respond. Network congestion may also influence the time it 1488 takes for a response to make it back to the client. If that 1489 time is too long, U-Boot will retransmit requests. In order 1490 to allow earlier responses to still be accepted after these 1491 retransmissions, U-Boot's BOOTP client keeps a small cache of 1492 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1493 cache. The default is to keep IDs for up to four outstanding 1494 requests. Increasing this will allow U-Boot to accept offers 1495 from a BOOTP client in networks with unusually high latency. 1496 1497- DHCP Advanced Options: 1498 You can fine tune the DHCP functionality by defining 1499 CONFIG_BOOTP_* symbols: 1500 1501 CONFIG_BOOTP_NISDOMAIN 1502 CONFIG_BOOTP_BOOTFILESIZE 1503 CONFIG_BOOTP_SEND_HOSTNAME 1504 CONFIG_BOOTP_NTPSERVER 1505 CONFIG_BOOTP_TIMEOFFSET 1506 CONFIG_BOOTP_VENDOREX 1507 CONFIG_BOOTP_MAY_FAIL 1508 1509 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1510 environment variable, not the BOOTP server. 1511 1512 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1513 after the configured retry count, the call will fail 1514 instead of starting over. This can be used to fail over 1515 to Link-local IP address configuration if the DHCP server 1516 is not available. 1517 1518 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1519 to do a dynamic update of a DNS server. To do this, they 1520 need the hostname of the DHCP requester. 1521 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1522 of the "hostname" environment variable is passed as 1523 option 12 to the DHCP server. 1524 1525 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1526 1527 A 32bit value in microseconds for a delay between 1528 receiving a "DHCP Offer" and sending the "DHCP Request". 1529 This fixes a problem with certain DHCP servers that don't 1530 respond 100% of the time to a "DHCP request". E.g. On an 1531 AT91RM9200 processor running at 180MHz, this delay needed 1532 to be *at least* 15,000 usec before a Windows Server 2003 1533 DHCP server would reply 100% of the time. I recommend at 1534 least 50,000 usec to be safe. The alternative is to hope 1535 that one of the retries will be successful but note that 1536 the DHCP timeout and retry process takes a longer than 1537 this delay. 1538 1539 - Link-local IP address negotiation: 1540 Negotiate with other link-local clients on the local network 1541 for an address that doesn't require explicit configuration. 1542 This is especially useful if a DHCP server cannot be guaranteed 1543 to exist in all environments that the device must operate. 1544 1545 See doc/README.link-local for more information. 1546 1547 - MAC address from environment variables 1548 1549 FDT_SEQ_MACADDR_FROM_ENV 1550 1551 Fix-up device tree with MAC addresses fetched sequentially from 1552 environment variables. This config work on assumption that 1553 non-usable ethernet node of device-tree are either not present 1554 or their status has been marked as "disabled". 1555 1556 - CDP Options: 1557 CONFIG_CDP_DEVICE_ID 1558 1559 The device id used in CDP trigger frames. 1560 1561 CONFIG_CDP_DEVICE_ID_PREFIX 1562 1563 A two character string which is prefixed to the MAC address 1564 of the device. 1565 1566 CONFIG_CDP_PORT_ID 1567 1568 A printf format string which contains the ascii name of 1569 the port. Normally is set to "eth%d" which sets 1570 eth0 for the first Ethernet, eth1 for the second etc. 1571 1572 CONFIG_CDP_CAPABILITIES 1573 1574 A 32bit integer which indicates the device capabilities; 1575 0x00000010 for a normal host which does not forwards. 1576 1577 CONFIG_CDP_VERSION 1578 1579 An ascii string containing the version of the software. 1580 1581 CONFIG_CDP_PLATFORM 1582 1583 An ascii string containing the name of the platform. 1584 1585 CONFIG_CDP_TRIGGER 1586 1587 A 32bit integer sent on the trigger. 1588 1589 CONFIG_CDP_POWER_CONSUMPTION 1590 1591 A 16bit integer containing the power consumption of the 1592 device in .1 of milliwatts. 1593 1594 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1595 1596 A byte containing the id of the VLAN. 1597 1598- Status LED: CONFIG_LED_STATUS 1599 1600 Several configurations allow to display the current 1601 status using a LED. For instance, the LED will blink 1602 fast while running U-Boot code, stop blinking as 1603 soon as a reply to a BOOTP request was received, and 1604 start blinking slow once the Linux kernel is running 1605 (supported by a status LED driver in the Linux 1606 kernel). Defining CONFIG_LED_STATUS enables this 1607 feature in U-Boot. 1608 1609 Additional options: 1610 1611 CONFIG_LED_STATUS_GPIO 1612 The status LED can be connected to a GPIO pin. 1613 In such cases, the gpio_led driver can be used as a 1614 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1615 to include the gpio_led driver in the U-Boot binary. 1616 1617 CONFIG_GPIO_LED_INVERTED_TABLE 1618 Some GPIO connected LEDs may have inverted polarity in which 1619 case the GPIO high value corresponds to LED off state and 1620 GPIO low value corresponds to LED on state. 1621 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1622 with a list of GPIO LEDs that have inverted polarity. 1623 1624- I2C Support: CONFIG_SYS_I2C 1625 1626 This enable the NEW i2c subsystem, and will allow you to use 1627 i2c commands at the u-boot command line (as long as you set 1628 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c 1629 based realtime clock chips or other i2c devices. See 1630 common/cmd_i2c.c for a description of the command line 1631 interface. 1632 1633 ported i2c driver to the new framework: 1634 - drivers/i2c/soft_i2c.c: 1635 - activate first bus with CONFIG_SYS_I2C_SOFT define 1636 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1637 for defining speed and slave address 1638 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1639 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1640 for defining speed and slave address 1641 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1642 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1643 for defining speed and slave address 1644 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1645 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1646 for defining speed and slave address 1647 1648 - drivers/i2c/fsl_i2c.c: 1649 - activate i2c driver with CONFIG_SYS_I2C_FSL 1650 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1651 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1652 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1653 bus. 1654 - If your board supports a second fsl i2c bus, define 1655 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1656 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1657 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1658 second bus. 1659 1660 - drivers/i2c/tegra_i2c.c: 1661 - activate this driver with CONFIG_SYS_I2C_TEGRA 1662 - This driver adds 4 i2c buses with a fix speed from 1663 100000 and the slave addr 0! 1664 1665 - drivers/i2c/ppc4xx_i2c.c 1666 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1667 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1668 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1669 1670 - drivers/i2c/i2c_mxc.c 1671 - activate this driver with CONFIG_SYS_I2C_MXC 1672 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1673 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1674 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1675 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1676 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1677 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1678 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1679 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1680 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1681 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1682 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1683 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1684 If those defines are not set, default value is 100000 1685 for speed, and 0 for slave. 1686 1687 - drivers/i2c/rcar_i2c.c: 1688 - activate this driver with CONFIG_SYS_I2C_RCAR 1689 - This driver adds 4 i2c buses 1690 1691 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 1692 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 1693 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 1694 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 1695 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 1696 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 1697 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 1698 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 1699 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses 1700 1701 - drivers/i2c/sh_i2c.c: 1702 - activate this driver with CONFIG_SYS_I2C_SH 1703 - This driver adds from 2 to 5 i2c buses 1704 1705 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1706 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1707 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1708 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1709 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1710 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1711 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1712 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1713 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1714 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1715 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1716 1717 - drivers/i2c/omap24xx_i2c.c 1718 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1719 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1720 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1721 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1722 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1723 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1724 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1725 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1726 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1727 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1728 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1729 1730 - drivers/i2c/zynq_i2c.c 1731 - activate this driver with CONFIG_SYS_I2C_ZYNQ 1732 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting 1733 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr 1734 1735 - drivers/i2c/s3c24x0_i2c.c: 1736 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1737 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1738 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1739 with a fix speed from 100000 and the slave addr 0! 1740 1741 - drivers/i2c/ihs_i2c.c 1742 - activate this driver with CONFIG_SYS_I2C_IHS 1743 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1744 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1745 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1746 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1747 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1748 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1749 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1750 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1751 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1752 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1753 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1754 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1755 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1756 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1757 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1758 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1759 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1760 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1761 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1762 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1763 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1764 1765 additional defines: 1766 1767 CONFIG_SYS_NUM_I2C_BUSES 1768 Hold the number of i2c buses you want to use. 1769 1770 CONFIG_SYS_I2C_DIRECT_BUS 1771 define this, if you don't use i2c muxes on your hardware. 1772 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1773 omit this define. 1774 1775 CONFIG_SYS_I2C_MAX_HOPS 1776 define how many muxes are maximal consecutively connected 1777 on one i2c bus. If you not use i2c muxes, omit this 1778 define. 1779 1780 CONFIG_SYS_I2C_BUSES 1781 hold a list of buses you want to use, only used if 1782 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1783 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1784 CONFIG_SYS_NUM_I2C_BUSES = 9: 1785 1786 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1787 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1788 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1789 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1790 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1791 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1792 {1, {I2C_NULL_HOP}}, \ 1793 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1794 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1795 } 1796 1797 which defines 1798 bus 0 on adapter 0 without a mux 1799 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1800 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1801 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1802 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1803 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1804 bus 6 on adapter 1 without a mux 1805 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1806 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1807 1808 If you do not have i2c muxes on your board, omit this define. 1809 1810- Legacy I2C Support: 1811 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1812 then the following macros need to be defined (examples are 1813 from include/configs/lwmon.h): 1814 1815 I2C_INIT 1816 1817 (Optional). Any commands necessary to enable the I2C 1818 controller or configure ports. 1819 1820 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1821 1822 I2C_ACTIVE 1823 1824 The code necessary to make the I2C data line active 1825 (driven). If the data line is open collector, this 1826 define can be null. 1827 1828 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1829 1830 I2C_TRISTATE 1831 1832 The code necessary to make the I2C data line tri-stated 1833 (inactive). If the data line is open collector, this 1834 define can be null. 1835 1836 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1837 1838 I2C_READ 1839 1840 Code that returns true if the I2C data line is high, 1841 false if it is low. 1842 1843 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1844 1845 I2C_SDA(bit) 1846 1847 If <bit> is true, sets the I2C data line high. If it 1848 is false, it clears it (low). 1849 1850 eg: #define I2C_SDA(bit) \ 1851 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1852 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1853 1854 I2C_SCL(bit) 1855 1856 If <bit> is true, sets the I2C clock line high. If it 1857 is false, it clears it (low). 1858 1859 eg: #define I2C_SCL(bit) \ 1860 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1861 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1862 1863 I2C_DELAY 1864 1865 This delay is invoked four times per clock cycle so this 1866 controls the rate of data transfer. The data rate thus 1867 is 1 / (I2C_DELAY * 4). Often defined to be something 1868 like: 1869 1870 #define I2C_DELAY udelay(2) 1871 1872 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1873 1874 If your arch supports the generic GPIO framework (asm/gpio.h), 1875 then you may alternatively define the two GPIOs that are to be 1876 used as SCL / SDA. Any of the previous I2C_xxx macros will 1877 have GPIO-based defaults assigned to them as appropriate. 1878 1879 You should define these to the GPIO value as given directly to 1880 the generic GPIO functions. 1881 1882 CONFIG_SYS_I2C_INIT_BOARD 1883 1884 When a board is reset during an i2c bus transfer 1885 chips might think that the current transfer is still 1886 in progress. On some boards it is possible to access 1887 the i2c SCLK line directly, either by using the 1888 processor pin as a GPIO or by having a second pin 1889 connected to the bus. If this option is defined a 1890 custom i2c_init_board() routine in boards/xxx/board.c 1891 is run early in the boot sequence. 1892 1893 CONFIG_I2C_MULTI_BUS 1894 1895 This option allows the use of multiple I2C buses, each of which 1896 must have a controller. At any point in time, only one bus is 1897 active. To switch to a different bus, use the 'i2c dev' command. 1898 Note that bus numbering is zero-based. 1899 1900 CONFIG_SYS_I2C_NOPROBES 1901 1902 This option specifies a list of I2C devices that will be skipped 1903 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1904 is set, specify a list of bus-device pairs. Otherwise, specify 1905 a 1D array of device addresses 1906 1907 e.g. 1908 #undef CONFIG_I2C_MULTI_BUS 1909 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1910 1911 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1912 1913 #define CONFIG_I2C_MULTI_BUS 1914 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1915 1916 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1917 1918 CONFIG_SYS_SPD_BUS_NUM 1919 1920 If defined, then this indicates the I2C bus number for DDR SPD. 1921 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1922 1923 CONFIG_SYS_RTC_BUS_NUM 1924 1925 If defined, then this indicates the I2C bus number for the RTC. 1926 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1927 1928 CONFIG_SOFT_I2C_READ_REPEATED_START 1929 1930 defining this will force the i2c_read() function in 1931 the soft_i2c driver to perform an I2C repeated start 1932 between writing the address pointer and reading the 1933 data. If this define is omitted the default behaviour 1934 of doing a stop-start sequence will be used. Most I2C 1935 devices can use either method, but some require one or 1936 the other. 1937 1938- SPI Support: CONFIG_SPI 1939 1940 Enables SPI driver (so far only tested with 1941 SPI EEPROM, also an instance works with Crystal A/D and 1942 D/As on the SACSng board) 1943 1944 CONFIG_SOFT_SPI 1945 1946 Enables a software (bit-bang) SPI driver rather than 1947 using hardware support. This is a general purpose 1948 driver that only requires three general I/O port pins 1949 (two outputs, one input) to function. If this is 1950 defined, the board configuration must define several 1951 SPI configuration items (port pins to use, etc). For 1952 an example, see include/configs/sacsng.h. 1953 1954 CONFIG_HARD_SPI 1955 1956 Enables a hardware SPI driver for general-purpose reads 1957 and writes. As with CONFIG_SOFT_SPI, the board configuration 1958 must define a list of chip-select function pointers. 1959 Currently supported on some MPC8xxx processors. For an 1960 example, see include/configs/mpc8349emds.h. 1961 1962 CONFIG_SYS_SPI_MXC_WAIT 1963 Timeout for waiting until spi transfer completed. 1964 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1965 1966- FPGA Support: CONFIG_FPGA 1967 1968 Enables FPGA subsystem. 1969 1970 CONFIG_FPGA_<vendor> 1971 1972 Enables support for specific chip vendors. 1973 (ALTERA, XILINX) 1974 1975 CONFIG_FPGA_<family> 1976 1977 Enables support for FPGA family. 1978 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1979 1980 CONFIG_FPGA_COUNT 1981 1982 Specify the number of FPGA devices to support. 1983 1984 CONFIG_SYS_FPGA_PROG_FEEDBACK 1985 1986 Enable printing of hash marks during FPGA configuration. 1987 1988 CONFIG_SYS_FPGA_CHECK_BUSY 1989 1990 Enable checks on FPGA configuration interface busy 1991 status by the configuration function. This option 1992 will require a board or device specific function to 1993 be written. 1994 1995 CONFIG_FPGA_DELAY 1996 1997 If defined, a function that provides delays in the FPGA 1998 configuration driver. 1999 2000 CONFIG_SYS_FPGA_CHECK_CTRLC 2001 Allow Control-C to interrupt FPGA configuration 2002 2003 CONFIG_SYS_FPGA_CHECK_ERROR 2004 2005 Check for configuration errors during FPGA bitfile 2006 loading. For example, abort during Virtex II 2007 configuration if the INIT_B line goes low (which 2008 indicated a CRC error). 2009 2010 CONFIG_SYS_FPGA_WAIT_INIT 2011 2012 Maximum time to wait for the INIT_B line to de-assert 2013 after PROB_B has been de-asserted during a Virtex II 2014 FPGA configuration sequence. The default time is 500 2015 ms. 2016 2017 CONFIG_SYS_FPGA_WAIT_BUSY 2018 2019 Maximum time to wait for BUSY to de-assert during 2020 Virtex II FPGA configuration. The default is 5 ms. 2021 2022 CONFIG_SYS_FPGA_WAIT_CONFIG 2023 2024 Time to wait after FPGA configuration. The default is 2025 200 ms. 2026 2027- Configuration Management: 2028 CONFIG_BUILD_TARGET 2029 2030 Some SoCs need special image types (e.g. U-Boot binary 2031 with a special header) as build targets. By defining 2032 CONFIG_BUILD_TARGET in the SoC / board header, this 2033 special image will be automatically built upon calling 2034 make / buildman. 2035 2036 CONFIG_IDENT_STRING 2037 2038 If defined, this string will be added to the U-Boot 2039 version information (U_BOOT_VERSION) 2040 2041- Vendor Parameter Protection: 2042 2043 U-Boot considers the values of the environment 2044 variables "serial#" (Board Serial Number) and 2045 "ethaddr" (Ethernet Address) to be parameters that 2046 are set once by the board vendor / manufacturer, and 2047 protects these variables from casual modification by 2048 the user. Once set, these variables are read-only, 2049 and write or delete attempts are rejected. You can 2050 change this behaviour: 2051 2052 If CONFIG_ENV_OVERWRITE is #defined in your config 2053 file, the write protection for vendor parameters is 2054 completely disabled. Anybody can change or delete 2055 these parameters. 2056 2057 Alternatively, if you define _both_ an ethaddr in the 2058 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 2059 Ethernet address is installed in the environment, 2060 which can be changed exactly ONCE by the user. [The 2061 serial# is unaffected by this, i. e. it remains 2062 read-only.] 2063 2064 The same can be accomplished in a more flexible way 2065 for any variable by configuring the type of access 2066 to allow for those variables in the ".flags" variable 2067 or define CONFIG_ENV_FLAGS_LIST_STATIC. 2068 2069- Protected RAM: 2070 CONFIG_PRAM 2071 2072 Define this variable to enable the reservation of 2073 "protected RAM", i. e. RAM which is not overwritten 2074 by U-Boot. Define CONFIG_PRAM to hold the number of 2075 kB you want to reserve for pRAM. You can overwrite 2076 this default value by defining an environment 2077 variable "pram" to the number of kB you want to 2078 reserve. Note that the board info structure will 2079 still show the full amount of RAM. If pRAM is 2080 reserved, a new environment variable "mem" will 2081 automatically be defined to hold the amount of 2082 remaining RAM in a form that can be passed as boot 2083 argument to Linux, for instance like that: 2084 2085 setenv bootargs ... mem=\${mem} 2086 saveenv 2087 2088 This way you can tell Linux not to use this memory, 2089 either, which results in a memory region that will 2090 not be affected by reboots. 2091 2092 *WARNING* If your board configuration uses automatic 2093 detection of the RAM size, you must make sure that 2094 this memory test is non-destructive. So far, the 2095 following board configurations are known to be 2096 "pRAM-clean": 2097 2098 IVMS8, IVML24, SPD8xx, 2099 HERMES, IP860, RPXlite, LWMON, 2100 FLAGADM 2101 2102- Access to physical memory region (> 4GB) 2103 Some basic support is provided for operations on memory not 2104 normally accessible to U-Boot - e.g. some architectures 2105 support access to more than 4GB of memory on 32-bit 2106 machines using physical address extension or similar. 2107 Define CONFIG_PHYSMEM to access this basic support, which 2108 currently only supports clearing the memory. 2109 2110- Error Recovery: 2111 CONFIG_NET_RETRY_COUNT 2112 2113 This variable defines the number of retries for 2114 network operations like ARP, RARP, TFTP, or BOOTP 2115 before giving up the operation. If not defined, a 2116 default value of 5 is used. 2117 2118 CONFIG_ARP_TIMEOUT 2119 2120 Timeout waiting for an ARP reply in milliseconds. 2121 2122 CONFIG_NFS_TIMEOUT 2123 2124 Timeout in milliseconds used in NFS protocol. 2125 If you encounter "ERROR: Cannot umount" in nfs command, 2126 try longer timeout such as 2127 #define CONFIG_NFS_TIMEOUT 10000UL 2128 2129- Command Interpreter: 2130 CONFIG_SYS_PROMPT_HUSH_PS2 2131 2132 This defines the secondary prompt string, which is 2133 printed when the command interpreter needs more input 2134 to complete a command. Usually "> ". 2135 2136 Note: 2137 2138 In the current implementation, the local variables 2139 space and global environment variables space are 2140 separated. Local variables are those you define by 2141 simply typing `name=value'. To access a local 2142 variable later on, you have write `$name' or 2143 `${name}'; to execute the contents of a variable 2144 directly type `$name' at the command prompt. 2145 2146 Global environment variables are those you use 2147 setenv/printenv to work with. To run a command stored 2148 in such a variable, you need to use the run command, 2149 and you must not use the '$' sign to access them. 2150 2151 To store commands and special characters in a 2152 variable, please use double quotation marks 2153 surrounding the whole text of the variable, instead 2154 of the backslashes before semicolons and special 2155 symbols. 2156 2157- Command Line Editing and History: 2158 CONFIG_CMDLINE_PS_SUPPORT 2159 2160 Enable support for changing the command prompt string 2161 at run-time. Only static string is supported so far. 2162 The string is obtained from environment variables PS1 2163 and PS2. 2164 2165- Default Environment: 2166 CONFIG_EXTRA_ENV_SETTINGS 2167 2168 Define this to contain any number of null terminated 2169 strings (variable = value pairs) that will be part of 2170 the default environment compiled into the boot image. 2171 2172 For example, place something like this in your 2173 board's config file: 2174 2175 #define CONFIG_EXTRA_ENV_SETTINGS \ 2176 "myvar1=value1\0" \ 2177 "myvar2=value2\0" 2178 2179 Warning: This method is based on knowledge about the 2180 internal format how the environment is stored by the 2181 U-Boot code. This is NOT an official, exported 2182 interface! Although it is unlikely that this format 2183 will change soon, there is no guarantee either. 2184 You better know what you are doing here. 2185 2186 Note: overly (ab)use of the default environment is 2187 discouraged. Make sure to check other ways to preset 2188 the environment like the "source" command or the 2189 boot command first. 2190 2191 CONFIG_DELAY_ENVIRONMENT 2192 2193 Normally the environment is loaded when the board is 2194 initialised so that it is available to U-Boot. This inhibits 2195 that so that the environment is not available until 2196 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 2197 this is instead controlled by the value of 2198 /config/load-environment. 2199 2200- Serial Flash support 2201 Usage requires an initial 'sf probe' to define the serial 2202 flash parameters, followed by read/write/erase/update 2203 commands. 2204 2205 The following defaults may be provided by the platform 2206 to handle the common case when only a single serial 2207 flash is present on the system. 2208 2209 CONFIG_SF_DEFAULT_BUS Bus identifier 2210 CONFIG_SF_DEFAULT_CS Chip-select 2211 CONFIG_SF_DEFAULT_MODE (see include/spi.h) 2212 CONFIG_SF_DEFAULT_SPEED in Hz 2213 2214 2215- TFTP Fixed UDP Port: 2216 CONFIG_TFTP_PORT 2217 2218 If this is defined, the environment variable tftpsrcp 2219 is used to supply the TFTP UDP source port value. 2220 If tftpsrcp isn't defined, the normal pseudo-random port 2221 number generator is used. 2222 2223 Also, the environment variable tftpdstp is used to supply 2224 the TFTP UDP destination port value. If tftpdstp isn't 2225 defined, the normal port 69 is used. 2226 2227 The purpose for tftpsrcp is to allow a TFTP server to 2228 blindly start the TFTP transfer using the pre-configured 2229 target IP address and UDP port. This has the effect of 2230 "punching through" the (Windows XP) firewall, allowing 2231 the remainder of the TFTP transfer to proceed normally. 2232 A better solution is to properly configure the firewall, 2233 but sometimes that is not allowed. 2234 2235- Show boot progress: 2236 CONFIG_SHOW_BOOT_PROGRESS 2237 2238 Defining this option allows to add some board- 2239 specific code (calling a user-provided function 2240 "show_boot_progress(int)") that enables you to show 2241 the system's boot progress on some display (for 2242 example, some LED's) on your board. At the moment, 2243 the following checkpoints are implemented: 2244 2245 2246Legacy uImage format: 2247 2248 Arg Where When 2249 1 common/cmd_bootm.c before attempting to boot an image 2250 -1 common/cmd_bootm.c Image header has bad magic number 2251 2 common/cmd_bootm.c Image header has correct magic number 2252 -2 common/cmd_bootm.c Image header has bad checksum 2253 3 common/cmd_bootm.c Image header has correct checksum 2254 -3 common/cmd_bootm.c Image data has bad checksum 2255 4 common/cmd_bootm.c Image data has correct checksum 2256 -4 common/cmd_bootm.c Image is for unsupported architecture 2257 5 common/cmd_bootm.c Architecture check OK 2258 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi) 2259 6 common/cmd_bootm.c Image Type check OK 2260 -6 common/cmd_bootm.c gunzip uncompression error 2261 -7 common/cmd_bootm.c Unimplemented compression type 2262 7 common/cmd_bootm.c Uncompression OK 2263 8 common/cmd_bootm.c No uncompress/copy overwrite error 2264 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 2265 2266 9 common/image.c Start initial ramdisk verification 2267 -10 common/image.c Ramdisk header has bad magic number 2268 -11 common/image.c Ramdisk header has bad checksum 2269 10 common/image.c Ramdisk header is OK 2270 -12 common/image.c Ramdisk data has bad checksum 2271 11 common/image.c Ramdisk data has correct checksum 2272 12 common/image.c Ramdisk verification complete, start loading 2273 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk) 2274 13 common/image.c Start multifile image verification 2275 14 common/image.c No initial ramdisk, no multifile, continue. 2276 2277 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS 2278 2279 -30 arch/powerpc/lib/board.c Fatal error, hang the system 2280 -31 post/post.c POST test failed, detected by post_output_backlog() 2281 -32 post/post.c POST test failed, detected by post_run_single() 2282 2283 34 common/cmd_doc.c before loading a Image from a DOC device 2284 -35 common/cmd_doc.c Bad usage of "doc" command 2285 35 common/cmd_doc.c correct usage of "doc" command 2286 -36 common/cmd_doc.c No boot device 2287 36 common/cmd_doc.c correct boot device 2288 -37 common/cmd_doc.c Unknown Chip ID on boot device 2289 37 common/cmd_doc.c correct chip ID found, device available 2290 -38 common/cmd_doc.c Read Error on boot device 2291 38 common/cmd_doc.c reading Image header from DOC device OK 2292 -39 common/cmd_doc.c Image header has bad magic number 2293 39 common/cmd_doc.c Image header has correct magic number 2294 -40 common/cmd_doc.c Error reading Image from DOC device 2295 40 common/cmd_doc.c Image header has correct magic number 2296 41 common/cmd_ide.c before loading a Image from a IDE device 2297 -42 common/cmd_ide.c Bad usage of "ide" command 2298 42 common/cmd_ide.c correct usage of "ide" command 2299 -43 common/cmd_ide.c No boot device 2300 43 common/cmd_ide.c boot device found 2301 -44 common/cmd_ide.c Device not available 2302 44 common/cmd_ide.c Device available 2303 -45 common/cmd_ide.c wrong partition selected 2304 45 common/cmd_ide.c partition selected 2305 -46 common/cmd_ide.c Unknown partition table 2306 46 common/cmd_ide.c valid partition table found 2307 -47 common/cmd_ide.c Invalid partition type 2308 47 common/cmd_ide.c correct partition type 2309 -48 common/cmd_ide.c Error reading Image Header on boot device 2310 48 common/cmd_ide.c reading Image Header from IDE device OK 2311 -49 common/cmd_ide.c Image header has bad magic number 2312 49 common/cmd_ide.c Image header has correct magic number 2313 -50 common/cmd_ide.c Image header has bad checksum 2314 50 common/cmd_ide.c Image header has correct checksum 2315 -51 common/cmd_ide.c Error reading Image from IDE device 2316 51 common/cmd_ide.c reading Image from IDE device OK 2317 52 common/cmd_nand.c before loading a Image from a NAND device 2318 -53 common/cmd_nand.c Bad usage of "nand" command 2319 53 common/cmd_nand.c correct usage of "nand" command 2320 -54 common/cmd_nand.c No boot device 2321 54 common/cmd_nand.c boot device found 2322 -55 common/cmd_nand.c Unknown Chip ID on boot device 2323 55 common/cmd_nand.c correct chip ID found, device available 2324 -56 common/cmd_nand.c Error reading Image Header on boot device 2325 56 common/cmd_nand.c reading Image Header from NAND device OK 2326 -57 common/cmd_nand.c Image header has bad magic number 2327 57 common/cmd_nand.c Image header has correct magic number 2328 -58 common/cmd_nand.c Error reading Image from NAND device 2329 58 common/cmd_nand.c reading Image from NAND device OK 2330 2331 -60 common/env_common.c Environment has a bad CRC, using default 2332 2333 64 net/eth.c starting with Ethernet configuration. 2334 -64 net/eth.c no Ethernet found. 2335 65 net/eth.c Ethernet found. 2336 2337 -80 common/cmd_net.c usage wrong 2338 80 common/cmd_net.c before calling net_loop() 2339 -81 common/cmd_net.c some error in net_loop() occurred 2340 81 common/cmd_net.c net_loop() back without error 2341 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 2342 82 common/cmd_net.c trying automatic boot 2343 83 common/cmd_net.c running "source" command 2344 -83 common/cmd_net.c some error in automatic boot or "source" command 2345 84 common/cmd_net.c end without errors 2346 2347FIT uImage format: 2348 2349 Arg Where When 2350 100 common/cmd_bootm.c Kernel FIT Image has correct format 2351 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format 2352 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration 2353 -101 common/cmd_bootm.c Can't get configuration for kernel subimage 2354 102 common/cmd_bootm.c Kernel unit name specified 2355 -103 common/cmd_bootm.c Can't get kernel subimage node offset 2356 103 common/cmd_bootm.c Found configuration node 2357 104 common/cmd_bootm.c Got kernel subimage node offset 2358 -104 common/cmd_bootm.c Kernel subimage hash verification failed 2359 105 common/cmd_bootm.c Kernel subimage hash verification OK 2360 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture 2361 106 common/cmd_bootm.c Architecture check OK 2362 -106 common/cmd_bootm.c Kernel subimage has wrong type 2363 107 common/cmd_bootm.c Kernel subimage type OK 2364 -107 common/cmd_bootm.c Can't get kernel subimage data/size 2365 108 common/cmd_bootm.c Got kernel subimage data/size 2366 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT) 2367 -109 common/cmd_bootm.c Can't get kernel subimage type 2368 -110 common/cmd_bootm.c Can't get kernel subimage comp 2369 -111 common/cmd_bootm.c Can't get kernel subimage os 2370 -112 common/cmd_bootm.c Can't get kernel subimage load address 2371 -113 common/cmd_bootm.c Image uncompress/copy overwrite error 2372 2373 120 common/image.c Start initial ramdisk verification 2374 -120 common/image.c Ramdisk FIT image has incorrect format 2375 121 common/image.c Ramdisk FIT image has correct format 2376 122 common/image.c No ramdisk subimage unit name, using configuration 2377 -122 common/image.c Can't get configuration for ramdisk subimage 2378 123 common/image.c Ramdisk unit name specified 2379 -124 common/image.c Can't get ramdisk subimage node offset 2380 125 common/image.c Got ramdisk subimage node offset 2381 -125 common/image.c Ramdisk subimage hash verification failed 2382 126 common/image.c Ramdisk subimage hash verification OK 2383 -126 common/image.c Ramdisk subimage for unsupported architecture 2384 127 common/image.c Architecture check OK 2385 -127 common/image.c Can't get ramdisk subimage data/size 2386 128 common/image.c Got ramdisk subimage data/size 2387 129 common/image.c Can't get ramdisk load address 2388 -129 common/image.c Got ramdisk load address 2389 2390 -130 common/cmd_doc.c Incorrect FIT image format 2391 131 common/cmd_doc.c FIT image format OK 2392 2393 -140 common/cmd_ide.c Incorrect FIT image format 2394 141 common/cmd_ide.c FIT image format OK 2395 2396 -150 common/cmd_nand.c Incorrect FIT image format 2397 151 common/cmd_nand.c FIT image format OK 2398 2399- Standalone program support: 2400 CONFIG_STANDALONE_LOAD_ADDR 2401 2402 This option defines a board specific value for the 2403 address where standalone program gets loaded, thus 2404 overwriting the architecture dependent default 2405 settings. 2406 2407- Frame Buffer Address: 2408 CONFIG_FB_ADDR 2409 2410 Define CONFIG_FB_ADDR if you want to use specific 2411 address for frame buffer. This is typically the case 2412 when using a graphics controller has separate video 2413 memory. U-Boot will then place the frame buffer at 2414 the given address instead of dynamically reserving it 2415 in system RAM by calling lcd_setmem(), which grabs 2416 the memory for the frame buffer depending on the 2417 configured panel size. 2418 2419 Please see board_init_f function. 2420 2421- Automatic software updates via TFTP server 2422 CONFIG_UPDATE_TFTP 2423 CONFIG_UPDATE_TFTP_CNT_MAX 2424 CONFIG_UPDATE_TFTP_MSEC_MAX 2425 2426 These options enable and control the auto-update feature; 2427 for a more detailed description refer to doc/README.update. 2428 2429- MTD Support (mtdparts command, UBI support) 2430 CONFIG_MTD_UBI_WL_THRESHOLD 2431 This parameter defines the maximum difference between the highest 2432 erase counter value and the lowest erase counter value of eraseblocks 2433 of UBI devices. When this threshold is exceeded, UBI starts performing 2434 wear leveling by means of moving data from eraseblock with low erase 2435 counter to eraseblocks with high erase counter. 2436 2437 The default value should be OK for SLC NAND flashes, NOR flashes and 2438 other flashes which have eraseblock life-cycle 100000 or more. 2439 However, in case of MLC NAND flashes which typically have eraseblock 2440 life-cycle less than 10000, the threshold should be lessened (e.g., 2441 to 128 or 256, although it does not have to be power of 2). 2442 2443 default: 4096 2444 2445 CONFIG_MTD_UBI_BEB_LIMIT 2446 This option specifies the maximum bad physical eraseblocks UBI 2447 expects on the MTD device (per 1024 eraseblocks). If the 2448 underlying flash does not admit of bad eraseblocks (e.g. NOR 2449 flash), this value is ignored. 2450 2451 NAND datasheets often specify the minimum and maximum NVM 2452 (Number of Valid Blocks) for the flashes' endurance lifetime. 2453 The maximum expected bad eraseblocks per 1024 eraseblocks 2454 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2455 which gives 20 for most NANDs (MaxNVB is basically the total 2456 count of eraseblocks on the chip). 2457 2458 To put it differently, if this value is 20, UBI will try to 2459 reserve about 1.9% of physical eraseblocks for bad blocks 2460 handling. And that will be 1.9% of eraseblocks on the entire 2461 NAND chip, not just the MTD partition UBI attaches. This means 2462 that if you have, say, a NAND flash chip admits maximum 40 bad 2463 eraseblocks, and it is split on two MTD partitions of the same 2464 size, UBI will reserve 40 eraseblocks when attaching a 2465 partition. 2466 2467 default: 20 2468 2469 CONFIG_MTD_UBI_FASTMAP 2470 Fastmap is a mechanism which allows attaching an UBI device 2471 in nearly constant time. Instead of scanning the whole MTD device it 2472 only has to locate a checkpoint (called fastmap) on the device. 2473 The on-flash fastmap contains all information needed to attach 2474 the device. Using fastmap makes only sense on large devices where 2475 attaching by scanning takes long. UBI will not automatically install 2476 a fastmap on old images, but you can set the UBI parameter 2477 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2478 that fastmap-enabled images are still usable with UBI implementations 2479 without fastmap support. On typical flash devices the whole fastmap 2480 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2481 2482 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2483 Set this parameter to enable fastmap automatically on images 2484 without a fastmap. 2485 default: 0 2486 2487 CONFIG_MTD_UBI_FM_DEBUG 2488 Enable UBI fastmap debug 2489 default: 0 2490 2491- SPL framework 2492 CONFIG_SPL 2493 Enable building of SPL globally. 2494 2495 CONFIG_SPL_LDSCRIPT 2496 LDSCRIPT for linking the SPL binary. 2497 2498 CONFIG_SPL_MAX_FOOTPRINT 2499 Maximum size in memory allocated to the SPL, BSS included. 2500 When defined, the linker checks that the actual memory 2501 used by SPL from _start to __bss_end does not exceed it. 2502 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2503 must not be both defined at the same time. 2504 2505 CONFIG_SPL_MAX_SIZE 2506 Maximum size of the SPL image (text, data, rodata, and 2507 linker lists sections), BSS excluded. 2508 When defined, the linker checks that the actual size does 2509 not exceed it. 2510 2511 CONFIG_SPL_TEXT_BASE 2512 TEXT_BASE for linking the SPL binary. 2513 2514 CONFIG_SPL_RELOC_TEXT_BASE 2515 Address to relocate to. If unspecified, this is equal to 2516 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2517 2518 CONFIG_SPL_BSS_START_ADDR 2519 Link address for the BSS within the SPL binary. 2520 2521 CONFIG_SPL_BSS_MAX_SIZE 2522 Maximum size in memory allocated to the SPL BSS. 2523 When defined, the linker checks that the actual memory used 2524 by SPL from __bss_start to __bss_end does not exceed it. 2525 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2526 must not be both defined at the same time. 2527 2528 CONFIG_SPL_STACK 2529 Adress of the start of the stack SPL will use 2530 2531 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2532 When defined, SPL will panic() if the image it has 2533 loaded does not have a signature. 2534 Defining this is useful when code which loads images 2535 in SPL cannot guarantee that absolutely all read errors 2536 will be caught. 2537 An example is the LPC32XX MLC NAND driver, which will 2538 consider that a completely unreadable NAND block is bad, 2539 and thus should be skipped silently. 2540 2541 CONFIG_SPL_RELOC_STACK 2542 Adress of the start of the stack SPL will use after 2543 relocation. If unspecified, this is equal to 2544 CONFIG_SPL_STACK. 2545 2546 CONFIG_SYS_SPL_MALLOC_START 2547 Starting address of the malloc pool used in SPL. 2548 When this option is set the full malloc is used in SPL and 2549 it is set up by spl_init() and before that, the simple malloc() 2550 can be used if CONFIG_SYS_MALLOC_F is defined. 2551 2552 CONFIG_SYS_SPL_MALLOC_SIZE 2553 The size of the malloc pool used in SPL. 2554 2555 CONFIG_SPL_OS_BOOT 2556 Enable booting directly to an OS from SPL. 2557 See also: doc/README.falcon 2558 2559 CONFIG_SPL_DISPLAY_PRINT 2560 For ARM, enable an optional function to print more information 2561 about the running system. 2562 2563 CONFIG_SPL_INIT_MINIMAL 2564 Arch init code should be built for a very small image 2565 2566 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2567 Partition on the MMC to load U-Boot from when the MMC is being 2568 used in raw mode 2569 2570 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2571 Sector to load kernel uImage from when MMC is being 2572 used in raw mode (for Falcon mode) 2573 2574 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2575 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2576 Sector and number of sectors to load kernel argument 2577 parameters from when MMC is being used in raw mode 2578 (for falcon mode) 2579 2580 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 2581 Partition on the MMC to load U-Boot from when the MMC is being 2582 used in fs mode 2583 2584 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2585 Filename to read to load U-Boot when reading from filesystem 2586 2587 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2588 Filename to read to load kernel uImage when reading 2589 from filesystem (for Falcon mode) 2590 2591 CONFIG_SPL_FS_LOAD_ARGS_NAME 2592 Filename to read to load kernel argument parameters 2593 when reading from filesystem (for Falcon mode) 2594 2595 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2596 Set this for NAND SPL on PPC mpc83xx targets, so that 2597 start.S waits for the rest of the SPL to load before 2598 continuing (the hardware starts execution after just 2599 loading the first page rather than the full 4K). 2600 2601 CONFIG_SPL_SKIP_RELOCATE 2602 Avoid SPL relocation 2603 2604 CONFIG_SPL_NAND_BASE 2605 Include nand_base.c in the SPL. Requires 2606 CONFIG_SPL_NAND_DRIVERS. 2607 2608 CONFIG_SPL_NAND_DRIVERS 2609 SPL uses normal NAND drivers, not minimal drivers. 2610 2611 CONFIG_SPL_NAND_IDENT 2612 SPL uses the chip ID list to identify the NAND flash. 2613 Requires CONFIG_SPL_NAND_BASE. 2614 2615 CONFIG_SPL_NAND_ECC 2616 Include standard software ECC in the SPL 2617 2618 CONFIG_SPL_NAND_SIMPLE 2619 Support for NAND boot using simple NAND drivers that 2620 expose the cmd_ctrl() interface. 2621 2622 CONFIG_SPL_UBI 2623 Support for a lightweight UBI (fastmap) scanner and 2624 loader 2625 2626 CONFIG_SPL_NAND_RAW_ONLY 2627 Support to boot only raw u-boot.bin images. Use this only 2628 if you need to save space. 2629 2630 CONFIG_SPL_COMMON_INIT_DDR 2631 Set for common ddr init with serial presence detect in 2632 SPL binary. 2633 2634 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2635 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2636 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2637 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2638 CONFIG_SYS_NAND_ECCBYTES 2639 Defines the size and behavior of the NAND that SPL uses 2640 to read U-Boot 2641 2642 CONFIG_SPL_NAND_BOOT 2643 Add support NAND boot 2644 2645 CONFIG_SYS_NAND_U_BOOT_OFFS 2646 Location in NAND to read U-Boot from 2647 2648 CONFIG_SYS_NAND_U_BOOT_DST 2649 Location in memory to load U-Boot to 2650 2651 CONFIG_SYS_NAND_U_BOOT_SIZE 2652 Size of image to load 2653 2654 CONFIG_SYS_NAND_U_BOOT_START 2655 Entry point in loaded image to jump to 2656 2657 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2658 Define this if you need to first read the OOB and then the 2659 data. This is used, for example, on davinci platforms. 2660 2661 CONFIG_SPL_RAM_DEVICE 2662 Support for running image already present in ram, in SPL binary 2663 2664 CONFIG_SPL_PAD_TO 2665 Image offset to which the SPL should be padded before appending 2666 the SPL payload. By default, this is defined as 2667 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2668 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2669 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2670 2671 CONFIG_SPL_TARGET 2672 Final target image containing SPL and payload. Some SPLs 2673 use an arch-specific makefile fragment instead, for 2674 example if more than one image needs to be produced. 2675 2676 CONFIG_SPL_FIT_PRINT 2677 Printing information about a FIT image adds quite a bit of 2678 code to SPL. So this is normally disabled in SPL. Use this 2679 option to re-enable it. This will affect the output of the 2680 bootm command when booting a FIT image. 2681 2682- TPL framework 2683 CONFIG_TPL 2684 Enable building of TPL globally. 2685 2686 CONFIG_TPL_PAD_TO 2687 Image offset to which the TPL should be padded before appending 2688 the TPL payload. By default, this is defined as 2689 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2690 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2691 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2692 2693- Interrupt support (PPC): 2694 2695 There are common interrupt_init() and timer_interrupt() 2696 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2697 for CPU specific initialization. interrupt_init_cpu() 2698 should set decrementer_count to appropriate value. If 2699 CPU resets decrementer automatically after interrupt 2700 (ppc4xx) it should set decrementer_count to zero. 2701 timer_interrupt() calls timer_interrupt_cpu() for CPU 2702 specific handling. If board has watchdog / status_led 2703 / other_activity_monitor it works automatically from 2704 general timer_interrupt(). 2705 2706 2707Board initialization settings: 2708------------------------------ 2709 2710During Initialization u-boot calls a number of board specific functions 2711to allow the preparation of board specific prerequisites, e.g. pin setup 2712before drivers are initialized. To enable these callbacks the 2713following configuration macros have to be defined. Currently this is 2714architecture specific, so please check arch/your_architecture/lib/board.c 2715typically in board_init_f() and board_init_r(). 2716 2717- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2718- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2719- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2720- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2721 2722Configuration Settings: 2723----------------------- 2724 2725- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2726 Optionally it can be defined to support 64-bit memory commands. 2727 2728- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2729 undefine this when you're short of memory. 2730 2731- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2732 width of the commands listed in the 'help' command output. 2733 2734- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2735 prompt for user input. 2736 2737- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2738 2739- CONFIG_SYS_PBSIZE: Buffer size for Console output 2740 2741- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2742 2743- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2744 the application (usually a Linux kernel) when it is 2745 booted 2746 2747- CONFIG_SYS_BAUDRATE_TABLE: 2748 List of legal baudrate settings for this board. 2749 2750- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: 2751 Begin and End addresses of the area used by the 2752 simple memory test. 2753 2754- CONFIG_SYS_MEMTEST_SCRATCH: 2755 Scratch address used by the alternate memory test 2756 You only need to set this if address zero isn't writeable 2757 2758- CONFIG_SYS_MEM_RESERVE_SECURE 2759 Only implemented for ARMv8 for now. 2760 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2761 is substracted from total RAM and won't be reported to OS. 2762 This memory can be used as secure memory. A variable 2763 gd->arch.secure_ram is used to track the location. In systems 2764 the RAM base is not zero, or RAM is divided into banks, 2765 this variable needs to be recalcuated to get the address. 2766 2767- CONFIG_SYS_MEM_TOP_HIDE: 2768 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2769 this specified memory area will get subtracted from the top 2770 (end) of RAM and won't get "touched" at all by U-Boot. By 2771 fixing up gd->ram_size the Linux kernel should gets passed 2772 the now "corrected" memory size and won't touch it either. 2773 This should work for arch/ppc and arch/powerpc. Only Linux 2774 board ports in arch/powerpc with bootwrapper support that 2775 recalculate the memory size from the SDRAM controller setup 2776 will have to get fixed in Linux additionally. 2777 2778 This option can be used as a workaround for the 440EPx/GRx 2779 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2780 be touched. 2781 2782 WARNING: Please make sure that this value is a multiple of 2783 the Linux page size (normally 4k). If this is not the case, 2784 then the end address of the Linux memory will be located at a 2785 non page size aligned address and this could cause major 2786 problems. 2787 2788- CONFIG_SYS_LOADS_BAUD_CHANGE: 2789 Enable temporary baudrate change while serial download 2790 2791- CONFIG_SYS_SDRAM_BASE: 2792 Physical start address of SDRAM. _Must_ be 0 here. 2793 2794- CONFIG_SYS_FLASH_BASE: 2795 Physical start address of Flash memory. 2796 2797- CONFIG_SYS_MONITOR_BASE: 2798 Physical start address of boot monitor code (set by 2799 make config files to be same as the text base address 2800 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2801 CONFIG_SYS_FLASH_BASE when booting from flash. 2802 2803- CONFIG_SYS_MONITOR_LEN: 2804 Size of memory reserved for monitor code, used to 2805 determine _at_compile_time_ (!) if the environment is 2806 embedded within the U-Boot image, or in a separate 2807 flash sector. 2808 2809- CONFIG_SYS_MALLOC_LEN: 2810 Size of DRAM reserved for malloc() use. 2811 2812- CONFIG_SYS_MALLOC_F_LEN 2813 Size of the malloc() pool for use before relocation. If 2814 this is defined, then a very simple malloc() implementation 2815 will become available before relocation. The address is just 2816 below the global data, and the stack is moved down to make 2817 space. 2818 2819 This feature allocates regions with increasing addresses 2820 within the region. calloc() is supported, but realloc() 2821 is not available. free() is supported but does nothing. 2822 The memory will be freed (or in fact just forgotten) when 2823 U-Boot relocates itself. 2824 2825- CONFIG_SYS_MALLOC_SIMPLE 2826 Provides a simple and small malloc() and calloc() for those 2827 boards which do not use the full malloc in SPL (which is 2828 enabled with CONFIG_SYS_SPL_MALLOC_START). 2829 2830- CONFIG_SYS_NONCACHED_MEMORY: 2831 Size of non-cached memory area. This area of memory will be 2832 typically located right below the malloc() area and mapped 2833 uncached in the MMU. This is useful for drivers that would 2834 otherwise require a lot of explicit cache maintenance. For 2835 some drivers it's also impossible to properly maintain the 2836 cache. For example if the regions that need to be flushed 2837 are not a multiple of the cache-line size, *and* padding 2838 cannot be allocated between the regions to align them (i.e. 2839 if the HW requires a contiguous array of regions, and the 2840 size of each region is not cache-aligned), then a flush of 2841 one region may result in overwriting data that hardware has 2842 written to another region in the same cache-line. This can 2843 happen for example in network drivers where descriptors for 2844 buffers are typically smaller than the CPU cache-line (e.g. 2845 16 bytes vs. 32 or 64 bytes). 2846 2847 Non-cached memory is only supported on 32-bit ARM at present. 2848 2849- CONFIG_SYS_BOOTM_LEN: 2850 Normally compressed uImages are limited to an 2851 uncompressed size of 8 MBytes. If this is not enough, 2852 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2853 to adjust this setting to your needs. 2854 2855- CONFIG_SYS_BOOTMAPSZ: 2856 Maximum size of memory mapped by the startup code of 2857 the Linux kernel; all data that must be processed by 2858 the Linux kernel (bd_info, boot arguments, FDT blob if 2859 used) must be put below this limit, unless "bootm_low" 2860 environment variable is defined and non-zero. In such case 2861 all data for the Linux kernel must be between "bootm_low" 2862 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2863 variable "bootm_mapsize" will override the value of 2864 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2865 then the value in "bootm_size" will be used instead. 2866 2867- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2868 Enable initrd_high functionality. If defined then the 2869 initrd_high feature is enabled and the bootm ramdisk subcommand 2870 is enabled. 2871 2872- CONFIG_SYS_BOOT_GET_CMDLINE: 2873 Enables allocating and saving kernel cmdline in space between 2874 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2875 2876- CONFIG_SYS_BOOT_GET_KBD: 2877 Enables allocating and saving a kernel copy of the bd_info in 2878 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2879 2880- CONFIG_SYS_MAX_FLASH_BANKS: 2881 Max number of Flash memory banks 2882 2883- CONFIG_SYS_MAX_FLASH_SECT: 2884 Max number of sectors on a Flash chip 2885 2886- CONFIG_SYS_FLASH_ERASE_TOUT: 2887 Timeout for Flash erase operations (in ms) 2888 2889- CONFIG_SYS_FLASH_WRITE_TOUT: 2890 Timeout for Flash write operations (in ms) 2891 2892- CONFIG_SYS_FLASH_LOCK_TOUT 2893 Timeout for Flash set sector lock bit operation (in ms) 2894 2895- CONFIG_SYS_FLASH_UNLOCK_TOUT 2896 Timeout for Flash clear lock bits operation (in ms) 2897 2898- CONFIG_SYS_FLASH_PROTECTION 2899 If defined, hardware flash sectors protection is used 2900 instead of U-Boot software protection. 2901 2902- CONFIG_SYS_DIRECT_FLASH_TFTP: 2903 2904 Enable TFTP transfers directly to flash memory; 2905 without this option such a download has to be 2906 performed in two steps: (1) download to RAM, and (2) 2907 copy from RAM to flash. 2908 2909 The two-step approach is usually more reliable, since 2910 you can check if the download worked before you erase 2911 the flash, but in some situations (when system RAM is 2912 too limited to allow for a temporary copy of the 2913 downloaded image) this option may be very useful. 2914 2915- CONFIG_SYS_FLASH_CFI: 2916 Define if the flash driver uses extra elements in the 2917 common flash structure for storing flash geometry. 2918 2919- CONFIG_FLASH_CFI_DRIVER 2920 This option also enables the building of the cfi_flash driver 2921 in the drivers directory 2922 2923- CONFIG_FLASH_CFI_MTD 2924 This option enables the building of the cfi_mtd driver 2925 in the drivers directory. The driver exports CFI flash 2926 to the MTD layer. 2927 2928- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2929 Use buffered writes to flash. 2930 2931- CONFIG_FLASH_SPANSION_S29WS_N 2932 s29ws-n MirrorBit flash has non-standard addresses for buffered 2933 write commands. 2934 2935- CONFIG_SYS_FLASH_QUIET_TEST 2936 If this option is defined, the common CFI flash doesn't 2937 print it's warning upon not recognized FLASH banks. This 2938 is useful, if some of the configured banks are only 2939 optionally available. 2940 2941- CONFIG_FLASH_SHOW_PROGRESS 2942 If defined (must be an integer), print out countdown 2943 digits and dots. Recommended value: 45 (9..1) for 80 2944 column displays, 15 (3..1) for 40 column displays. 2945 2946- CONFIG_FLASH_VERIFY 2947 If defined, the content of the flash (destination) is compared 2948 against the source after the write operation. An error message 2949 will be printed when the contents are not identical. 2950 Please note that this option is useless in nearly all cases, 2951 since such flash programming errors usually are detected earlier 2952 while unprotecting/erasing/programming. Please only enable 2953 this option if you really know what you are doing. 2954 2955- CONFIG_SYS_RX_ETH_BUFFER: 2956 Defines the number of Ethernet receive buffers. On some 2957 Ethernet controllers it is recommended to set this value 2958 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2959 buffers can be full shortly after enabling the interface 2960 on high Ethernet traffic. 2961 Defaults to 4 if not defined. 2962 2963- CONFIG_ENV_MAX_ENTRIES 2964 2965 Maximum number of entries in the hash table that is used 2966 internally to store the environment settings. The default 2967 setting is supposed to be generous and should work in most 2968 cases. This setting can be used to tune behaviour; see 2969 lib/hashtable.c for details. 2970 2971- CONFIG_ENV_FLAGS_LIST_DEFAULT 2972- CONFIG_ENV_FLAGS_LIST_STATIC 2973 Enable validation of the values given to environment variables when 2974 calling env set. Variables can be restricted to only decimal, 2975 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2976 the variables can also be restricted to IP address or MAC address. 2977 2978 The format of the list is: 2979 type_attribute = [s|d|x|b|i|m] 2980 access_attribute = [a|r|o|c] 2981 attributes = type_attribute[access_attribute] 2982 entry = variable_name[:attributes] 2983 list = entry[,list] 2984 2985 The type attributes are: 2986 s - String (default) 2987 d - Decimal 2988 x - Hexadecimal 2989 b - Boolean ([1yYtT|0nNfF]) 2990 i - IP address 2991 m - MAC address 2992 2993 The access attributes are: 2994 a - Any (default) 2995 r - Read-only 2996 o - Write-once 2997 c - Change-default 2998 2999 - CONFIG_ENV_FLAGS_LIST_DEFAULT 3000 Define this to a list (string) to define the ".flags" 3001 environment variable in the default or embedded environment. 3002 3003 - CONFIG_ENV_FLAGS_LIST_STATIC 3004 Define this to a list (string) to define validation that 3005 should be done if an entry is not found in the ".flags" 3006 environment variable. To override a setting in the static 3007 list, simply add an entry for the same variable name to the 3008 ".flags" variable. 3009 3010 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3011 regular expression. This allows multiple variables to define the same 3012 flags without explicitly listing them for each variable. 3013 3014- CONFIG_ENV_ACCESS_IGNORE_FORCE 3015 If defined, don't allow the -f switch to env set override variable 3016 access flags. 3017 3018The following definitions that deal with the placement and management 3019of environment data (variable area); in general, we support the 3020following configurations: 3021 3022- CONFIG_BUILD_ENVCRC: 3023 3024 Builds up envcrc with the target environment so that external utils 3025 may easily extract it and embed it in final U-Boot images. 3026 3027BE CAREFUL! The first access to the environment happens quite early 3028in U-Boot initialization (when we try to get the setting of for the 3029console baudrate). You *MUST* have mapped your NVRAM area then, or 3030U-Boot will hang. 3031 3032Please note that even with NVRAM we still use a copy of the 3033environment in RAM: we could work on NVRAM directly, but we want to 3034keep settings there always unmodified except somebody uses "saveenv" 3035to save the current settings. 3036 3037BE CAREFUL! For some special cases, the local device can not use 3038"saveenv" command. For example, the local device will get the 3039environment stored in a remote NOR flash by SRIO or PCIE link, 3040but it can not erase, write this NOR flash by SRIO or PCIE interface. 3041 3042- CONFIG_NAND_ENV_DST 3043 3044 Defines address in RAM to which the nand_spl code should copy the 3045 environment. If redundant environment is used, it will be copied to 3046 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 3047 3048Please note that the environment is read-only until the monitor 3049has been relocated to RAM and a RAM copy of the environment has been 3050created; also, when using EEPROM you will have to use env_get_f() 3051until then to read environment variables. 3052 3053The environment is protected by a CRC32 checksum. Before the monitor 3054is relocated into RAM, as a result of a bad CRC you will be working 3055with the compiled-in default environment - *silently*!!! [This is 3056necessary, because the first environment variable we need is the 3057"baudrate" setting for the console - if we have a bad CRC, we don't 3058have any device yet where we could complain.] 3059 3060Note: once the monitor has been relocated, then it will complain if 3061the default environment is used; a new CRC is computed as soon as you 3062use the "saveenv" command to store a valid environment. 3063 3064- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 3065 Echo the inverted Ethernet link state to the fault LED. 3066 3067 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 3068 also needs to be defined. 3069 3070- CONFIG_SYS_FAULT_MII_ADDR: 3071 MII address of the PHY to check for the Ethernet link state. 3072 3073- CONFIG_NS16550_MIN_FUNCTIONS: 3074 Define this if you desire to only have use of the NS16550_init 3075 and NS16550_putc functions for the serial driver located at 3076 drivers/serial/ns16550.c. This option is useful for saving 3077 space for already greatly restricted images, including but not 3078 limited to NAND_SPL configurations. 3079 3080- CONFIG_DISPLAY_BOARDINFO 3081 Display information about the board that U-Boot is running on 3082 when U-Boot starts up. The board function checkboard() is called 3083 to do this. 3084 3085- CONFIG_DISPLAY_BOARDINFO_LATE 3086 Similar to the previous option, but display this information 3087 later, once stdio is running and output goes to the LCD, if 3088 present. 3089 3090- CONFIG_BOARD_SIZE_LIMIT: 3091 Maximum size of the U-Boot image. When defined, the 3092 build system checks that the actual size does not 3093 exceed it. 3094 3095Low Level (hardware related) configuration options: 3096--------------------------------------------------- 3097 3098- CONFIG_SYS_CACHELINE_SIZE: 3099 Cache Line Size of the CPU. 3100 3101- CONFIG_SYS_CCSRBAR_DEFAULT: 3102 Default (power-on reset) physical address of CCSR on Freescale 3103 PowerPC SOCs. 3104 3105- CONFIG_SYS_CCSRBAR: 3106 Virtual address of CCSR. On a 32-bit build, this is typically 3107 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 3108 3109- CONFIG_SYS_CCSRBAR_PHYS: 3110 Physical address of CCSR. CCSR can be relocated to a new 3111 physical address, if desired. In this case, this macro should 3112 be set to that address. Otherwise, it should be set to the 3113 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 3114 is typically relocated on 36-bit builds. It is recommended 3115 that this macro be defined via the _HIGH and _LOW macros: 3116 3117 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 3118 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 3119 3120- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 3121 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 3122 either 0 (32-bit build) or 0xF (36-bit build). This macro is 3123 used in assembly code, so it must not contain typecasts or 3124 integer size suffixes (e.g. "ULL"). 3125 3126- CONFIG_SYS_CCSRBAR_PHYS_LOW: 3127 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 3128 used in assembly code, so it must not contain typecasts or 3129 integer size suffixes (e.g. "ULL"). 3130 3131- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 3132 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 3133 forced to a value that ensures that CCSR is not relocated. 3134 3135- Floppy Disk Support: 3136 CONFIG_SYS_FDC_DRIVE_NUMBER 3137 3138 the default drive number (default value 0) 3139 3140 CONFIG_SYS_ISA_IO_STRIDE 3141 3142 defines the spacing between FDC chipset registers 3143 (default value 1) 3144 3145 CONFIG_SYS_ISA_IO_OFFSET 3146 3147 defines the offset of register from address. It 3148 depends on which part of the data bus is connected to 3149 the FDC chipset. (default value 0) 3150 3151 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and 3152 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their 3153 default value. 3154 3155 if CONFIG_SYS_FDC_HW_INIT is defined, then the function 3156 fdc_hw_init() is called at the beginning of the FDC 3157 setup. fdc_hw_init() must be provided by the board 3158 source code. It is used to make hardware-dependent 3159 initializations. 3160 3161- CONFIG_IDE_AHB: 3162 Most IDE controllers were designed to be connected with PCI 3163 interface. Only few of them were designed for AHB interface. 3164 When software is doing ATA command and data transfer to 3165 IDE devices through IDE-AHB controller, some additional 3166 registers accessing to these kind of IDE-AHB controller 3167 is required. 3168 3169- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 3170 DO NOT CHANGE unless you know exactly what you're 3171 doing! (11-4) [MPC8xx systems only] 3172 3173- CONFIG_SYS_INIT_RAM_ADDR: 3174 3175 Start address of memory area that can be used for 3176 initial data and stack; please note that this must be 3177 writable memory that is working WITHOUT special 3178 initialization, i. e. you CANNOT use normal RAM which 3179 will become available only after programming the 3180 memory controller and running certain initialization 3181 sequences. 3182 3183 U-Boot uses the following memory types: 3184 - MPC8xx: IMMR (internal memory of the CPU) 3185 3186- CONFIG_SYS_GBL_DATA_OFFSET: 3187 3188 Offset of the initial data structure in the memory 3189 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 3190 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 3191 data is located at the end of the available space 3192 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 3193 GENERATED_GBL_DATA_SIZE), and the initial stack is just 3194 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 3195 CONFIG_SYS_GBL_DATA_OFFSET) downward. 3196 3197 Note: 3198 On the MPC824X (or other systems that use the data 3199 cache for initial memory) the address chosen for 3200 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 3201 point to an otherwise UNUSED address space between 3202 the top of RAM and the start of the PCI space. 3203 3204- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 3205 3206- CONFIG_SYS_OR_TIMING_SDRAM: 3207 SDRAM timing 3208 3209- CONFIG_SYS_MAMR_PTA: 3210 periodic timer for refresh 3211 3212- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 3213 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 3214 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 3215 CONFIG_SYS_BR1_PRELIM: 3216 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 3217 3218- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 3219 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 3220 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 3221 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 3222 3223- CONFIG_PCI_ENUM_ONLY 3224 Only scan through and get the devices on the buses. 3225 Don't do any setup work, presumably because someone or 3226 something has already done it, and we don't need to do it 3227 a second time. Useful for platforms that are pre-booted 3228 by coreboot or similar. 3229 3230- CONFIG_PCI_INDIRECT_BRIDGE: 3231 Enable support for indirect PCI bridges. 3232 3233- CONFIG_SYS_SRIO: 3234 Chip has SRIO or not 3235 3236- CONFIG_SRIO1: 3237 Board has SRIO 1 port available 3238 3239- CONFIG_SRIO2: 3240 Board has SRIO 2 port available 3241 3242- CONFIG_SRIO_PCIE_BOOT_MASTER 3243 Board can support master function for Boot from SRIO and PCIE 3244 3245- CONFIG_SYS_SRIOn_MEM_VIRT: 3246 Virtual Address of SRIO port 'n' memory region 3247 3248- CONFIG_SYS_SRIOn_MEM_PHYS: 3249 Physical Address of SRIO port 'n' memory region 3250 3251- CONFIG_SYS_SRIOn_MEM_SIZE: 3252 Size of SRIO port 'n' memory region 3253 3254- CONFIG_SYS_NAND_BUSWIDTH_16BIT 3255 Defined to tell the NAND controller that the NAND chip is using 3256 a 16 bit bus. 3257 Not all NAND drivers use this symbol. 3258 Example of drivers that use it: 3259 - drivers/mtd/nand/ndfc.c 3260 - drivers/mtd/nand/mxc_nand.c 3261 3262- CONFIG_SYS_NDFC_EBC0_CFG 3263 Sets the EBC0_CFG register for the NDFC. If not defined 3264 a default value will be used. 3265 3266- CONFIG_SPD_EEPROM 3267 Get DDR timing information from an I2C EEPROM. Common 3268 with pluggable memory modules such as SODIMMs 3269 3270 SPD_EEPROM_ADDRESS 3271 I2C address of the SPD EEPROM 3272 3273- CONFIG_SYS_SPD_BUS_NUM 3274 If SPD EEPROM is on an I2C bus other than the first 3275 one, specify here. Note that the value must resolve 3276 to something your driver can deal with. 3277 3278- CONFIG_SYS_DDR_RAW_TIMING 3279 Get DDR timing information from other than SPD. Common with 3280 soldered DDR chips onboard without SPD. DDR raw timing 3281 parameters are extracted from datasheet and hard-coded into 3282 header files or board specific files. 3283 3284- CONFIG_FSL_DDR_INTERACTIVE 3285 Enable interactive DDR debugging. See doc/README.fsl-ddr. 3286 3287- CONFIG_FSL_DDR_SYNC_REFRESH 3288 Enable sync of refresh for multiple controllers. 3289 3290- CONFIG_FSL_DDR_BIST 3291 Enable built-in memory test for Freescale DDR controllers. 3292 3293- CONFIG_SYS_83XX_DDR_USES_CS0 3294 Only for 83xx systems. If specified, then DDR should 3295 be configured using CS0 and CS1 instead of CS2 and CS3. 3296 3297- CONFIG_RMII 3298 Enable RMII mode for all FECs. 3299 Note that this is a global option, we can't 3300 have one FEC in standard MII mode and another in RMII mode. 3301 3302- CONFIG_CRC32_VERIFY 3303 Add a verify option to the crc32 command. 3304 The syntax is: 3305 3306 => crc32 -v <address> <count> <crc32> 3307 3308 Where address/count indicate a memory area 3309 and crc32 is the correct crc32 which the 3310 area should have. 3311 3312- CONFIG_LOOPW 3313 Add the "loopw" memory command. This only takes effect if 3314 the memory commands are activated globally (CONFIG_CMD_MEMORY). 3315 3316- CONFIG_MX_CYCLIC 3317 Add the "mdc" and "mwc" memory commands. These are cyclic 3318 "md/mw" commands. 3319 Examples: 3320 3321 => mdc.b 10 4 500 3322 This command will print 4 bytes (10,11,12,13) each 500 ms. 3323 3324 => mwc.l 100 12345678 10 3325 This command will write 12345678 to address 100 all 10 ms. 3326 3327 This only takes effect if the memory commands are activated 3328 globally (CONFIG_CMD_MEMORY). 3329 3330- CONFIG_SKIP_LOWLEVEL_INIT 3331 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 3332 low level initializations (like setting up the memory 3333 controller) are omitted and/or U-Boot does not 3334 relocate itself into RAM. 3335 3336 Normally this variable MUST NOT be defined. The only 3337 exception is when U-Boot is loaded (to RAM) by some 3338 other boot loader or by a debugger which performs 3339 these initializations itself. 3340 3341- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 3342 [ARM926EJ-S only] This allows just the call to lowlevel_init() 3343 to be skipped. The normal CP15 init (such as enabling the 3344 instruction cache) is still performed. 3345 3346- CONFIG_SPL_BUILD 3347 Modifies the behaviour of start.S when compiling a loader 3348 that is executed before the actual U-Boot. E.g. when 3349 compiling a NAND SPL. 3350 3351- CONFIG_TPL_BUILD 3352 Modifies the behaviour of start.S when compiling a loader 3353 that is executed after the SPL and before the actual U-Boot. 3354 It is loaded by the SPL. 3355 3356- CONFIG_SYS_MPC85XX_NO_RESETVEC 3357 Only for 85xx systems. If this variable is specified, the section 3358 .resetvec is not kept and the section .bootpg is placed in the 3359 previous 4k of the .text section. 3360 3361- CONFIG_ARCH_MAP_SYSMEM 3362 Generally U-Boot (and in particular the md command) uses 3363 effective address. It is therefore not necessary to regard 3364 U-Boot address as virtual addresses that need to be translated 3365 to physical addresses. However, sandbox requires this, since 3366 it maintains its own little RAM buffer which contains all 3367 addressable memory. This option causes some memory accesses 3368 to be mapped through map_sysmem() / unmap_sysmem(). 3369 3370- CONFIG_X86_RESET_VECTOR 3371 If defined, the x86 reset vector code is included. This is not 3372 needed when U-Boot is running from Coreboot. 3373 3374- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 3375 Option to disable subpage write in NAND driver 3376 driver that uses this: 3377 drivers/mtd/nand/davinci_nand.c 3378 3379Freescale QE/FMAN Firmware Support: 3380----------------------------------- 3381 3382The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 3383loading of "firmware", which is encoded in the QE firmware binary format. 3384This firmware often needs to be loaded during U-Boot booting, so macros 3385are used to identify the storage device (NOR flash, SPI, etc) and the address 3386within that device. 3387 3388- CONFIG_SYS_FMAN_FW_ADDR 3389 The address in the storage device where the FMAN microcode is located. The 3390 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3391 is also specified. 3392 3393- CONFIG_SYS_QE_FW_ADDR 3394 The address in the storage device where the QE microcode is located. The 3395 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3396 is also specified. 3397 3398- CONFIG_SYS_QE_FMAN_FW_LENGTH 3399 The maximum possible size of the firmware. The firmware binary format 3400 has a field that specifies the actual size of the firmware, but it 3401 might not be possible to read any part of the firmware unless some 3402 local storage is allocated to hold the entire firmware first. 3403 3404- CONFIG_SYS_QE_FMAN_FW_IN_NOR 3405 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 3406 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 3407 virtual address in NOR flash. 3408 3409- CONFIG_SYS_QE_FMAN_FW_IN_NAND 3410 Specifies that QE/FMAN firmware is located in NAND flash. 3411 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 3412 3413- CONFIG_SYS_QE_FMAN_FW_IN_MMC 3414 Specifies that QE/FMAN firmware is located on the primary SD/MMC 3415 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 3416 3417- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 3418 Specifies that QE/FMAN firmware is located in the remote (master) 3419 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 3420 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 3421 window->master inbound window->master LAW->the ucode address in 3422 master's memory space. 3423 3424Freescale Layerscape Management Complex Firmware Support: 3425--------------------------------------------------------- 3426The Freescale Layerscape Management Complex (MC) supports the loading of 3427"firmware". 3428This firmware often needs to be loaded during U-Boot booting, so macros 3429are used to identify the storage device (NOR flash, SPI, etc) and the address 3430within that device. 3431 3432- CONFIG_FSL_MC_ENET 3433 Enable the MC driver for Layerscape SoCs. 3434 3435Freescale Layerscape Debug Server Support: 3436------------------------------------------- 3437The Freescale Layerscape Debug Server Support supports the loading of 3438"Debug Server firmware" and triggering SP boot-rom. 3439This firmware often needs to be loaded during U-Boot booting. 3440 3441- CONFIG_SYS_MC_RSV_MEM_ALIGN 3442 Define alignment of reserved memory MC requires 3443 3444Reproducible builds 3445------------------- 3446 3447In order to achieve reproducible builds, timestamps used in the U-Boot build 3448process have to be set to a fixed value. 3449 3450This is done using the SOURCE_DATE_EPOCH environment variable. 3451SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3452option for U-Boot or an environment variable in U-Boot. 3453 3454SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3455 3456Building the Software: 3457====================== 3458 3459Building U-Boot has been tested in several native build environments 3460and in many different cross environments. Of course we cannot support 3461all possibly existing versions of cross development tools in all 3462(potentially obsolete) versions. In case of tool chain problems we 3463recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) 3464which is extensively used to build and test U-Boot. 3465 3466If you are not using a native environment, it is assumed that you 3467have GNU cross compiling tools available in your path. In this case, 3468you must set the environment variable CROSS_COMPILE in your shell. 3469Note that no changes to the Makefile or any other source files are 3470necessary. For example using the ELDK on a 4xx CPU, please enter: 3471 3472 $ CROSS_COMPILE=ppc_4xx- 3473 $ export CROSS_COMPILE 3474 3475Note: If you wish to generate Windows versions of the utilities in 3476 the tools directory you can use the MinGW toolchain 3477 (http://www.mingw.org). Set your HOST tools to the MinGW 3478 toolchain and execute 'make tools'. For example: 3479 3480 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools 3481 3482 Binaries such as tools/mkimage.exe will be created which can 3483 be executed on computers running Windows. 3484 3485U-Boot is intended to be simple to build. After installing the 3486sources you must configure U-Boot for one specific board type. This 3487is done by typing: 3488 3489 make NAME_defconfig 3490 3491where "NAME_defconfig" is the name of one of the existing configu- 3492rations; see boards.cfg for supported names. 3493 3494Note: for some board special configuration names may exist; check if 3495 additional information is available from the board vendor; for 3496 instance, the TQM823L systems are available without (standard) 3497 or with LCD support. You can select such additional "features" 3498 when choosing the configuration, i. e. 3499 3500 make TQM823L_defconfig 3501 - will configure for a plain TQM823L, i. e. no LCD support 3502 3503 make TQM823L_LCD_defconfig 3504 - will configure for a TQM823L with U-Boot console on LCD 3505 3506 etc. 3507 3508 3509Finally, type "make all", and you should get some working U-Boot 3510images ready for download to / installation on your system: 3511 3512- "u-boot.bin" is a raw binary image 3513- "u-boot" is an image in ELF binary format 3514- "u-boot.srec" is in Motorola S-Record format 3515 3516By default the build is performed locally and the objects are saved 3517in the source directory. One of the two methods can be used to change 3518this behavior and build U-Boot to some external directory: 3519 35201. Add O= to the make command line invocations: 3521 3522 make O=/tmp/build distclean 3523 make O=/tmp/build NAME_defconfig 3524 make O=/tmp/build all 3525 35262. Set environment variable KBUILD_OUTPUT to point to the desired location: 3527 3528 export KBUILD_OUTPUT=/tmp/build 3529 make distclean 3530 make NAME_defconfig 3531 make all 3532 3533Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3534variable. 3535 3536User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3537setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3538For example to treat all compiler warnings as errors: 3539 3540 make KCFLAGS=-Werror 3541 3542Please be aware that the Makefiles assume you are using GNU make, so 3543for instance on NetBSD you might need to use "gmake" instead of 3544native "make". 3545 3546 3547If the system board that you have is not listed, then you will need 3548to port U-Boot to your hardware platform. To do this, follow these 3549steps: 3550 35511. Create a new directory to hold your board specific code. Add any 3552 files you need. In your board directory, you will need at least 3553 the "Makefile" and a "<board>.c". 35542. Create a new configuration file "include/configs/<board>.h" for 3555 your board. 35563. If you're porting U-Boot to a new CPU, then also create a new 3557 directory to hold your CPU specific code. Add any files you need. 35584. Run "make <board>_defconfig" with your new name. 35595. Type "make", and you should get a working "u-boot.srec" file 3560 to be installed on your target system. 35616. Debug and solve any problems that might arise. 3562 [Of course, this last step is much harder than it sounds.] 3563 3564 3565Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3566============================================================== 3567 3568If you have modified U-Boot sources (for instance added a new board 3569or support for new devices, a new CPU, etc.) you are expected to 3570provide feedback to the other developers. The feedback normally takes 3571the form of a "patch", i. e. a context diff against a certain (latest 3572official or latest in the git repository) version of U-Boot sources. 3573 3574But before you submit such a patch, please verify that your modifi- 3575cation did not break existing code. At least make sure that *ALL* of 3576the supported boards compile WITHOUT ANY compiler warnings. To do so, 3577just run the buildman script (tools/buildman/buildman), which will 3578configure and build U-Boot for ALL supported system. Be warned, this 3579will take a while. Please see the buildman README, or run 'buildman -H' 3580for documentation. 3581 3582 3583See also "U-Boot Porting Guide" below. 3584 3585 3586Monitor Commands - Overview: 3587============================ 3588 3589go - start application at address 'addr' 3590run - run commands in an environment variable 3591bootm - boot application image from memory 3592bootp - boot image via network using BootP/TFTP protocol 3593bootz - boot zImage from memory 3594tftpboot- boot image via network using TFTP protocol 3595 and env variables "ipaddr" and "serverip" 3596 (and eventually "gatewayip") 3597tftpput - upload a file via network using TFTP protocol 3598rarpboot- boot image via network using RARP/TFTP protocol 3599diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3600loads - load S-Record file over serial line 3601loadb - load binary file over serial line (kermit mode) 3602md - memory display 3603mm - memory modify (auto-incrementing) 3604nm - memory modify (constant address) 3605mw - memory write (fill) 3606cp - memory copy 3607cmp - memory compare 3608crc32 - checksum calculation 3609i2c - I2C sub-system 3610sspi - SPI utility commands 3611base - print or set address offset 3612printenv- print environment variables 3613setenv - set environment variables 3614saveenv - save environment variables to persistent storage 3615protect - enable or disable FLASH write protection 3616erase - erase FLASH memory 3617flinfo - print FLASH memory information 3618nand - NAND memory operations (see doc/README.nand) 3619bdinfo - print Board Info structure 3620iminfo - print header information for application image 3621coninfo - print console devices and informations 3622ide - IDE sub-system 3623loop - infinite loop on address range 3624loopw - infinite write loop on address range 3625mtest - simple RAM test 3626icache - enable or disable instruction cache 3627dcache - enable or disable data cache 3628reset - Perform RESET of the CPU 3629echo - echo args to console 3630version - print monitor version 3631help - print online help 3632? - alias for 'help' 3633 3634 3635Monitor Commands - Detailed Description: 3636======================================== 3637 3638TODO. 3639 3640For now: just type "help <command>". 3641 3642 3643Environment Variables: 3644====================== 3645 3646U-Boot supports user configuration using Environment Variables which 3647can be made persistent by saving to Flash memory. 3648 3649Environment Variables are set using "setenv", printed using 3650"printenv", and saved to Flash using "saveenv". Using "setenv" 3651without a value can be used to delete a variable from the 3652environment. As long as you don't save the environment you are 3653working with an in-memory copy. In case the Flash area containing the 3654environment is erased by accident, a default environment is provided. 3655 3656Some configuration options can be set using Environment Variables. 3657 3658List of environment variables (most likely not complete): 3659 3660 baudrate - see CONFIG_BAUDRATE 3661 3662 bootdelay - see CONFIG_BOOTDELAY 3663 3664 bootcmd - see CONFIG_BOOTCOMMAND 3665 3666 bootargs - Boot arguments when booting an RTOS image 3667 3668 bootfile - Name of the image to load with TFTP 3669 3670 bootm_low - Memory range available for image processing in the bootm 3671 command can be restricted. This variable is given as 3672 a hexadecimal number and defines lowest address allowed 3673 for use by the bootm command. See also "bootm_size" 3674 environment variable. Address defined by "bootm_low" is 3675 also the base of the initial memory mapping for the Linux 3676 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3677 bootm_mapsize. 3678 3679 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3680 This variable is given as a hexadecimal number and it 3681 defines the size of the memory region starting at base 3682 address bootm_low that is accessible by the Linux kernel 3683 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3684 as the default value if it is defined, and bootm_size is 3685 used otherwise. 3686 3687 bootm_size - Memory range available for image processing in the bootm 3688 command can be restricted. This variable is given as 3689 a hexadecimal number and defines the size of the region 3690 allowed for use by the bootm command. See also "bootm_low" 3691 environment variable. 3692 3693 updatefile - Location of the software update file on a TFTP server, used 3694 by the automatic software update feature. Please refer to 3695 documentation in doc/README.update for more details. 3696 3697 autoload - if set to "no" (any string beginning with 'n'), 3698 "bootp" will just load perform a lookup of the 3699 configuration from the BOOTP server, but not try to 3700 load any image using TFTP 3701 3702 autostart - if set to "yes", an image loaded using the "bootp", 3703 "rarpboot", "tftpboot" or "diskboot" commands will 3704 be automatically started (by internally calling 3705 "bootm") 3706 3707 If set to "no", a standalone image passed to the 3708 "bootm" command will be copied to the load address 3709 (and eventually uncompressed), but NOT be started. 3710 This can be used to load and uncompress arbitrary 3711 data. 3712 3713 fdt_high - if set this restricts the maximum address that the 3714 flattened device tree will be copied into upon boot. 3715 For example, if you have a system with 1 GB memory 3716 at physical address 0x10000000, while Linux kernel 3717 only recognizes the first 704 MB as low memory, you 3718 may need to set fdt_high as 0x3C000000 to have the 3719 device tree blob be copied to the maximum address 3720 of the 704 MB low memory, so that Linux kernel can 3721 access it during the boot procedure. 3722 3723 If this is set to the special value 0xFFFFFFFF then 3724 the fdt will not be copied at all on boot. For this 3725 to work it must reside in writable memory, have 3726 sufficient padding on the end of it for u-boot to 3727 add the information it needs into it, and the memory 3728 must be accessible by the kernel. 3729 3730 fdtcontroladdr- if set this is the address of the control flattened 3731 device tree used by U-Boot when CONFIG_OF_CONTROL is 3732 defined. 3733 3734 i2cfast - (PPC405GP|PPC405EP only) 3735 if set to 'y' configures Linux I2C driver for fast 3736 mode (400kHZ). This environment variable is used in 3737 initialization code. So, for changes to be effective 3738 it must be saved and board must be reset. 3739 3740 initrd_high - restrict positioning of initrd images: 3741 If this variable is not set, initrd images will be 3742 copied to the highest possible address in RAM; this 3743 is usually what you want since it allows for 3744 maximum initrd size. If for some reason you want to 3745 make sure that the initrd image is loaded below the 3746 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3747 variable to a value of "no" or "off" or "0". 3748 Alternatively, you can set it to a maximum upper 3749 address to use (U-Boot will still check that it 3750 does not overwrite the U-Boot stack and data). 3751 3752 For instance, when you have a system with 16 MB 3753 RAM, and want to reserve 4 MB from use by Linux, 3754 you can do this by adding "mem=12M" to the value of 3755 the "bootargs" variable. However, now you must make 3756 sure that the initrd image is placed in the first 3757 12 MB as well - this can be done with 3758 3759 setenv initrd_high 00c00000 3760 3761 If you set initrd_high to 0xFFFFFFFF, this is an 3762 indication to U-Boot that all addresses are legal 3763 for the Linux kernel, including addresses in flash 3764 memory. In this case U-Boot will NOT COPY the 3765 ramdisk at all. This may be useful to reduce the 3766 boot time on your system, but requires that this 3767 feature is supported by your Linux kernel. 3768 3769 ipaddr - IP address; needed for tftpboot command 3770 3771 loadaddr - Default load address for commands like "bootp", 3772 "rarpboot", "tftpboot", "loadb" or "diskboot" 3773 3774 loads_echo - see CONFIG_LOADS_ECHO 3775 3776 serverip - TFTP server IP address; needed for tftpboot command 3777 3778 bootretry - see CONFIG_BOOT_RETRY_TIME 3779 3780 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3781 3782 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3783 3784 ethprime - controls which interface is used first. 3785 3786 ethact - controls which interface is currently active. 3787 For example you can do the following 3788 3789 => setenv ethact FEC 3790 => ping 192.168.0.1 # traffic sent on FEC 3791 => setenv ethact SCC 3792 => ping 10.0.0.1 # traffic sent on SCC 3793 3794 ethrotate - When set to "no" U-Boot does not go through all 3795 available network interfaces. 3796 It just stays at the currently selected interface. 3797 3798 netretry - When set to "no" each network operation will 3799 either succeed or fail without retrying. 3800 When set to "once" the network operation will 3801 fail when all the available network interfaces 3802 are tried once without success. 3803 Useful on scripts which control the retry operation 3804 themselves. 3805 3806 npe_ucode - set load address for the NPE microcode 3807 3808 silent_linux - If set then Linux will be told to boot silently, by 3809 changing the console to be empty. If "yes" it will be 3810 made silent. If "no" it will not be made silent. If 3811 unset, then it will be made silent if the U-Boot console 3812 is silent. 3813 3814 tftpsrcp - If this is set, the value is used for TFTP's 3815 UDP source port. 3816 3817 tftpdstp - If this is set, the value is used for TFTP's UDP 3818 destination port instead of the Well Know Port 69. 3819 3820 tftpblocksize - Block size to use for TFTP transfers; if not set, 3821 we use the TFTP server's default block size 3822 3823 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3824 seconds, minimum value is 1000 = 1 second). Defines 3825 when a packet is considered to be lost so it has to 3826 be retransmitted. The default is 5000 = 5 seconds. 3827 Lowering this value may make downloads succeed 3828 faster in networks with high packet loss rates or 3829 with unreliable TFTP servers. 3830 3831 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3832 unit, minimum value = 0). Defines how many timeouts 3833 can happen during a single file transfer before that 3834 transfer is aborted. The default is 10, and 0 means 3835 'no timeouts allowed'. Increasing this value may help 3836 downloads succeed with high packet loss rates, or with 3837 unreliable TFTP servers or client hardware. 3838 3839 vlan - When set to a value < 4095 the traffic over 3840 Ethernet is encapsulated/received over 802.1q 3841 VLAN tagged frames. 3842 3843 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3844 Unsigned value, in milliseconds. If not set, the period will 3845 be either the default (28000), or a value based on 3846 CONFIG_NET_RETRY_COUNT, if defined. This value has 3847 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3848 3849The following image location variables contain the location of images 3850used in booting. The "Image" column gives the role of the image and is 3851not an environment variable name. The other columns are environment 3852variable names. "File Name" gives the name of the file on a TFTP 3853server, "RAM Address" gives the location in RAM the image will be 3854loaded to, and "Flash Location" gives the image's address in NOR 3855flash or offset in NAND flash. 3856 3857*Note* - these variables don't have to be defined for all boards, some 3858boards currently use other variables for these purposes, and some 3859boards use these variables for other purposes. 3860 3861Image File Name RAM Address Flash Location 3862----- --------- ----------- -------------- 3863u-boot u-boot u-boot_addr_r u-boot_addr 3864Linux kernel bootfile kernel_addr_r kernel_addr 3865device tree blob fdtfile fdt_addr_r fdt_addr 3866ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3867 3868The following environment variables may be used and automatically 3869updated by the network boot commands ("bootp" and "rarpboot"), 3870depending the information provided by your boot server: 3871 3872 bootfile - see above 3873 dnsip - IP address of your Domain Name Server 3874 dnsip2 - IP address of your secondary Domain Name Server 3875 gatewayip - IP address of the Gateway (Router) to use 3876 hostname - Target hostname 3877 ipaddr - see above 3878 netmask - Subnet Mask 3879 rootpath - Pathname of the root filesystem on the NFS server 3880 serverip - see above 3881 3882 3883There are two special Environment Variables: 3884 3885 serial# - contains hardware identification information such 3886 as type string and/or serial number 3887 ethaddr - Ethernet address 3888 3889These variables can be set only once (usually during manufacturing of 3890the board). U-Boot refuses to delete or overwrite these variables 3891once they have been set once. 3892 3893 3894Further special Environment Variables: 3895 3896 ver - Contains the U-Boot version string as printed 3897 with the "version" command. This variable is 3898 readonly (see CONFIG_VERSION_VARIABLE). 3899 3900 3901Please note that changes to some configuration parameters may take 3902only effect after the next boot (yes, that's just like Windoze :-). 3903 3904 3905Callback functions for environment variables: 3906--------------------------------------------- 3907 3908For some environment variables, the behavior of u-boot needs to change 3909when their values are changed. This functionality allows functions to 3910be associated with arbitrary variables. On creation, overwrite, or 3911deletion, the callback will provide the opportunity for some side 3912effect to happen or for the change to be rejected. 3913 3914The callbacks are named and associated with a function using the 3915U_BOOT_ENV_CALLBACK macro in your board or driver code. 3916 3917These callbacks are associated with variables in one of two ways. The 3918static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3919in the board configuration to a string that defines a list of 3920associations. The list must be in the following format: 3921 3922 entry = variable_name[:callback_name] 3923 list = entry[,list] 3924 3925If the callback name is not specified, then the callback is deleted. 3926Spaces are also allowed anywhere in the list. 3927 3928Callbacks can also be associated by defining the ".callbacks" variable 3929with the same list format above. Any association in ".callbacks" will 3930override any association in the static list. You can define 3931CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3932".callbacks" environment variable in the default or embedded environment. 3933 3934If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3935regular expression. This allows multiple variables to be connected to 3936the same callback without explicitly listing them all out. 3937 3938The signature of the callback functions is: 3939 3940 int callback(const char *name, const char *value, enum env_op op, int flags) 3941 3942* name - changed environment variable 3943* value - new value of the environment variable 3944* op - operation (create, overwrite, or delete) 3945* flags - attributes of the environment variable change, see flags H_* in 3946 include/search.h 3947 3948The return value is 0 if the variable change is accepted and 1 otherwise. 3949 3950Command Line Parsing: 3951===================== 3952 3953There are two different command line parsers available with U-Boot: 3954the old "simple" one, and the much more powerful "hush" shell: 3955 3956Old, simple command line parser: 3957-------------------------------- 3958 3959- supports environment variables (through setenv / saveenv commands) 3960- several commands on one line, separated by ';' 3961- variable substitution using "... ${name} ..." syntax 3962- special characters ('$', ';') can be escaped by prefixing with '\', 3963 for example: 3964 setenv bootcmd bootm \${address} 3965- You can also escape text by enclosing in single apostrophes, for example: 3966 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 3967 3968Hush shell: 3969----------- 3970 3971- similar to Bourne shell, with control structures like 3972 if...then...else...fi, for...do...done; while...do...done, 3973 until...do...done, ... 3974- supports environment ("global") variables (through setenv / saveenv 3975 commands) and local shell variables (through standard shell syntax 3976 "name=value"); only environment variables can be used with "run" 3977 command 3978 3979General rules: 3980-------------- 3981 3982(1) If a command line (or an environment variable executed by a "run" 3983 command) contains several commands separated by semicolon, and 3984 one of these commands fails, then the remaining commands will be 3985 executed anyway. 3986 3987(2) If you execute several variables with one call to run (i. e. 3988 calling run with a list of variables as arguments), any failing 3989 command will cause "run" to terminate, i. e. the remaining 3990 variables are not executed. 3991 3992Note for Redundant Ethernet Interfaces: 3993======================================= 3994 3995Some boards come with redundant Ethernet interfaces; U-Boot supports 3996such configurations and is capable of automatic selection of a 3997"working" interface when needed. MAC assignment works as follows: 3998 3999Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 4000MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 4001"eth1addr" (=>eth1), "eth2addr", ... 4002 4003If the network interface stores some valid MAC address (for instance 4004in SROM), this is used as default address if there is NO correspon- 4005ding setting in the environment; if the corresponding environment 4006variable is set, this overrides the settings in the card; that means: 4007 4008o If the SROM has a valid MAC address, and there is no address in the 4009 environment, the SROM's address is used. 4010 4011o If there is no valid address in the SROM, and a definition in the 4012 environment exists, then the value from the environment variable is 4013 used. 4014 4015o If both the SROM and the environment contain a MAC address, and 4016 both addresses are the same, this MAC address is used. 4017 4018o If both the SROM and the environment contain a MAC address, and the 4019 addresses differ, the value from the environment is used and a 4020 warning is printed. 4021 4022o If neither SROM nor the environment contain a MAC address, an error 4023 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 4024 a random, locally-assigned MAC is used. 4025 4026If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 4027will be programmed into hardware as part of the initialization process. This 4028may be skipped by setting the appropriate 'ethmacskip' environment variable. 4029The naming convention is as follows: 4030"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 4031 4032Image Formats: 4033============== 4034 4035U-Boot is capable of booting (and performing other auxiliary operations on) 4036images in two formats: 4037 4038New uImage format (FIT) 4039----------------------- 4040 4041Flexible and powerful format based on Flattened Image Tree -- FIT (similar 4042to Flattened Device Tree). It allows the use of images with multiple 4043components (several kernels, ramdisks, etc.), with contents protected by 4044SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 4045 4046 4047Old uImage format 4048----------------- 4049 4050Old image format is based on binary files which can be basically anything, 4051preceded by a special header; see the definitions in include/image.h for 4052details; basically, the header defines the following image properties: 4053 4054* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 4055 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 4056 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 4057 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 4058 INTEGRITY). 4059* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 4060 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 4061 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 4062* Compression Type (uncompressed, gzip, bzip2) 4063* Load Address 4064* Entry Point 4065* Image Name 4066* Image Timestamp 4067 4068The header is marked by a special Magic Number, and both the header 4069and the data portions of the image are secured against corruption by 4070CRC32 checksums. 4071 4072 4073Linux Support: 4074============== 4075 4076Although U-Boot should support any OS or standalone application 4077easily, the main focus has always been on Linux during the design of 4078U-Boot. 4079 4080U-Boot includes many features that so far have been part of some 4081special "boot loader" code within the Linux kernel. Also, any 4082"initrd" images to be used are no longer part of one big Linux image; 4083instead, kernel and "initrd" are separate images. This implementation 4084serves several purposes: 4085 4086- the same features can be used for other OS or standalone 4087 applications (for instance: using compressed images to reduce the 4088 Flash memory footprint) 4089 4090- it becomes much easier to port new Linux kernel versions because 4091 lots of low-level, hardware dependent stuff are done by U-Boot 4092 4093- the same Linux kernel image can now be used with different "initrd" 4094 images; of course this also means that different kernel images can 4095 be run with the same "initrd". This makes testing easier (you don't 4096 have to build a new "zImage.initrd" Linux image when you just 4097 change a file in your "initrd"). Also, a field-upgrade of the 4098 software is easier now. 4099 4100 4101Linux HOWTO: 4102============ 4103 4104Porting Linux to U-Boot based systems: 4105--------------------------------------- 4106 4107U-Boot cannot save you from doing all the necessary modifications to 4108configure the Linux device drivers for use with your target hardware 4109(no, we don't intend to provide a full virtual machine interface to 4110Linux :-). 4111 4112But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 4113 4114Just make sure your machine specific header file (for instance 4115include/asm-ppc/tqm8xx.h) includes the same definition of the Board 4116Information structure as we define in include/asm-<arch>/u-boot.h, 4117and make sure that your definition of IMAP_ADDR uses the same value 4118as your U-Boot configuration in CONFIG_SYS_IMMR. 4119 4120Note that U-Boot now has a driver model, a unified model for drivers. 4121If you are adding a new driver, plumb it into driver model. If there 4122is no uclass available, you are encouraged to create one. See 4123doc/driver-model. 4124 4125 4126Configuring the Linux kernel: 4127----------------------------- 4128 4129No specific requirements for U-Boot. Make sure you have some root 4130device (initial ramdisk, NFS) for your target system. 4131 4132 4133Building a Linux Image: 4134----------------------- 4135 4136With U-Boot, "normal" build targets like "zImage" or "bzImage" are 4137not used. If you use recent kernel source, a new build target 4138"uImage" will exist which automatically builds an image usable by 4139U-Boot. Most older kernels also have support for a "pImage" target, 4140which was introduced for our predecessor project PPCBoot and uses a 4141100% compatible format. 4142 4143Example: 4144 4145 make TQM850L_defconfig 4146 make oldconfig 4147 make dep 4148 make uImage 4149 4150The "uImage" build target uses a special tool (in 'tools/mkimage') to 4151encapsulate a compressed Linux kernel image with header information, 4152CRC32 checksum etc. for use with U-Boot. This is what we are doing: 4153 4154* build a standard "vmlinux" kernel image (in ELF binary format): 4155 4156* convert the kernel into a raw binary image: 4157 4158 ${CROSS_COMPILE}-objcopy -O binary \ 4159 -R .note -R .comment \ 4160 -S vmlinux linux.bin 4161 4162* compress the binary image: 4163 4164 gzip -9 linux.bin 4165 4166* package compressed binary image for U-Boot: 4167 4168 mkimage -A ppc -O linux -T kernel -C gzip \ 4169 -a 0 -e 0 -n "Linux Kernel Image" \ 4170 -d linux.bin.gz uImage 4171 4172 4173The "mkimage" tool can also be used to create ramdisk images for use 4174with U-Boot, either separated from the Linux kernel image, or 4175combined into one file. "mkimage" encapsulates the images with a 64 4176byte header containing information about target architecture, 4177operating system, image type, compression method, entry points, time 4178stamp, CRC32 checksums, etc. 4179 4180"mkimage" can be called in two ways: to verify existing images and 4181print the header information, or to build new images. 4182 4183In the first form (with "-l" option) mkimage lists the information 4184contained in the header of an existing U-Boot image; this includes 4185checksum verification: 4186 4187 tools/mkimage -l image 4188 -l ==> list image header information 4189 4190The second form (with "-d" option) is used to build a U-Boot image 4191from a "data file" which is used as image payload: 4192 4193 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 4194 -n name -d data_file image 4195 -A ==> set architecture to 'arch' 4196 -O ==> set operating system to 'os' 4197 -T ==> set image type to 'type' 4198 -C ==> set compression type 'comp' 4199 -a ==> set load address to 'addr' (hex) 4200 -e ==> set entry point to 'ep' (hex) 4201 -n ==> set image name to 'name' 4202 -d ==> use image data from 'datafile' 4203 4204Right now, all Linux kernels for PowerPC systems use the same load 4205address (0x00000000), but the entry point address depends on the 4206kernel version: 4207 4208- 2.2.x kernels have the entry point at 0x0000000C, 4209- 2.3.x and later kernels have the entry point at 0x00000000. 4210 4211So a typical call to build a U-Boot image would read: 4212 4213 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4214 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 4215 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 4216 > examples/uImage.TQM850L 4217 Image Name: 2.4.4 kernel for TQM850L 4218 Created: Wed Jul 19 02:34:59 2000 4219 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4220 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4221 Load Address: 0x00000000 4222 Entry Point: 0x00000000 4223 4224To verify the contents of the image (or check for corruption): 4225 4226 -> tools/mkimage -l examples/uImage.TQM850L 4227 Image Name: 2.4.4 kernel for TQM850L 4228 Created: Wed Jul 19 02:34:59 2000 4229 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4230 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4231 Load Address: 0x00000000 4232 Entry Point: 0x00000000 4233 4234NOTE: for embedded systems where boot time is critical you can trade 4235speed for memory and install an UNCOMPRESSED image instead: this 4236needs more space in Flash, but boots much faster since it does not 4237need to be uncompressed: 4238 4239 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 4240 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4241 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 4242 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 4243 > examples/uImage.TQM850L-uncompressed 4244 Image Name: 2.4.4 kernel for TQM850L 4245 Created: Wed Jul 19 02:34:59 2000 4246 Image Type: PowerPC Linux Kernel Image (uncompressed) 4247 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 4248 Load Address: 0x00000000 4249 Entry Point: 0x00000000 4250 4251 4252Similar you can build U-Boot images from a 'ramdisk.image.gz' file 4253when your kernel is intended to use an initial ramdisk: 4254 4255 -> tools/mkimage -n 'Simple Ramdisk Image' \ 4256 > -A ppc -O linux -T ramdisk -C gzip \ 4257 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 4258 Image Name: Simple Ramdisk Image 4259 Created: Wed Jan 12 14:01:50 2000 4260 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4261 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 4262 Load Address: 0x00000000 4263 Entry Point: 0x00000000 4264 4265The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i" 4266option performs the converse operation of the mkimage's second form (the "-d" 4267option). Given an image built by mkimage, the dumpimage extracts a "data file" 4268from the image: 4269 4270 tools/dumpimage -i image -T type -p position data_file 4271 -i ==> extract from the 'image' a specific 'data_file' 4272 -T ==> set image type to 'type' 4273 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image' 4274 4275 4276Installing a Linux Image: 4277------------------------- 4278 4279To downloading a U-Boot image over the serial (console) interface, 4280you must convert the image to S-Record format: 4281 4282 objcopy -I binary -O srec examples/image examples/image.srec 4283 4284The 'objcopy' does not understand the information in the U-Boot 4285image header, so the resulting S-Record file will be relative to 4286address 0x00000000. To load it to a given address, you need to 4287specify the target address as 'offset' parameter with the 'loads' 4288command. 4289 4290Example: install the image to address 0x40100000 (which on the 4291TQM8xxL is in the first Flash bank): 4292 4293 => erase 40100000 401FFFFF 4294 4295 .......... done 4296 Erased 8 sectors 4297 4298 => loads 40100000 4299 ## Ready for S-Record download ... 4300 ~>examples/image.srec 4301 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 4302 ... 4303 15989 15990 15991 15992 4304 [file transfer complete] 4305 [connected] 4306 ## Start Addr = 0x00000000 4307 4308 4309You can check the success of the download using the 'iminfo' command; 4310this includes a checksum verification so you can be sure no data 4311corruption happened: 4312 4313 => imi 40100000 4314 4315 ## Checking Image at 40100000 ... 4316 Image Name: 2.2.13 for initrd on TQM850L 4317 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4318 Data Size: 335725 Bytes = 327 kB = 0 MB 4319 Load Address: 00000000 4320 Entry Point: 0000000c 4321 Verifying Checksum ... OK 4322 4323 4324Boot Linux: 4325----------- 4326 4327The "bootm" command is used to boot an application that is stored in 4328memory (RAM or Flash). In case of a Linux kernel image, the contents 4329of the "bootargs" environment variable is passed to the kernel as 4330parameters. You can check and modify this variable using the 4331"printenv" and "setenv" commands: 4332 4333 4334 => printenv bootargs 4335 bootargs=root=/dev/ram 4336 4337 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4338 4339 => printenv bootargs 4340 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4341 4342 => bootm 40020000 4343 ## Booting Linux kernel at 40020000 ... 4344 Image Name: 2.2.13 for NFS on TQM850L 4345 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4346 Data Size: 381681 Bytes = 372 kB = 0 MB 4347 Load Address: 00000000 4348 Entry Point: 0000000c 4349 Verifying Checksum ... OK 4350 Uncompressing Kernel Image ... OK 4351 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000 4352 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4353 time_init: decrementer frequency = 187500000/60 4354 Calibrating delay loop... 49.77 BogoMIPS 4355 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 4356 ... 4357 4358If you want to boot a Linux kernel with initial RAM disk, you pass 4359the memory addresses of both the kernel and the initrd image (PPBCOOT 4360format!) to the "bootm" command: 4361 4362 => imi 40100000 40200000 4363 4364 ## Checking Image at 40100000 ... 4365 Image Name: 2.2.13 for initrd on TQM850L 4366 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4367 Data Size: 335725 Bytes = 327 kB = 0 MB 4368 Load Address: 00000000 4369 Entry Point: 0000000c 4370 Verifying Checksum ... OK 4371 4372 ## Checking Image at 40200000 ... 4373 Image Name: Simple Ramdisk Image 4374 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4375 Data Size: 566530 Bytes = 553 kB = 0 MB 4376 Load Address: 00000000 4377 Entry Point: 00000000 4378 Verifying Checksum ... OK 4379 4380 => bootm 40100000 40200000 4381 ## Booting Linux kernel at 40100000 ... 4382 Image Name: 2.2.13 for initrd on TQM850L 4383 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4384 Data Size: 335725 Bytes = 327 kB = 0 MB 4385 Load Address: 00000000 4386 Entry Point: 0000000c 4387 Verifying Checksum ... OK 4388 Uncompressing Kernel Image ... OK 4389 ## Loading RAMDisk Image at 40200000 ... 4390 Image Name: Simple Ramdisk Image 4391 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4392 Data Size: 566530 Bytes = 553 kB = 0 MB 4393 Load Address: 00000000 4394 Entry Point: 00000000 4395 Verifying Checksum ... OK 4396 Loading Ramdisk ... OK 4397 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000 4398 Boot arguments: root=/dev/ram 4399 time_init: decrementer frequency = 187500000/60 4400 Calibrating delay loop... 49.77 BogoMIPS 4401 ... 4402 RAMDISK: Compressed image found at block 0 4403 VFS: Mounted root (ext2 filesystem). 4404 4405 bash# 4406 4407Boot Linux and pass a flat device tree: 4408----------- 4409 4410First, U-Boot must be compiled with the appropriate defines. See the section 4411titled "Linux Kernel Interface" above for a more in depth explanation. The 4412following is an example of how to start a kernel and pass an updated 4413flat device tree: 4414 4415=> print oftaddr 4416oftaddr=0x300000 4417=> print oft 4418oft=oftrees/mpc8540ads.dtb 4419=> tftp $oftaddr $oft 4420Speed: 1000, full duplex 4421Using TSEC0 device 4422TFTP from server 192.168.1.1; our IP address is 192.168.1.101 4423Filename 'oftrees/mpc8540ads.dtb'. 4424Load address: 0x300000 4425Loading: # 4426done 4427Bytes transferred = 4106 (100a hex) 4428=> tftp $loadaddr $bootfile 4429Speed: 1000, full duplex 4430Using TSEC0 device 4431TFTP from server 192.168.1.1; our IP address is 192.168.1.2 4432Filename 'uImage'. 4433Load address: 0x200000 4434Loading:############ 4435done 4436Bytes transferred = 1029407 (fb51f hex) 4437=> print loadaddr 4438loadaddr=200000 4439=> print oftaddr 4440oftaddr=0x300000 4441=> bootm $loadaddr - $oftaddr 4442## Booting image at 00200000 ... 4443 Image Name: Linux-2.6.17-dirty 4444 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4445 Data Size: 1029343 Bytes = 1005.2 kB 4446 Load Address: 00000000 4447 Entry Point: 00000000 4448 Verifying Checksum ... OK 4449 Uncompressing Kernel Image ... OK 4450Booting using flat device tree at 0x300000 4451Using MPC85xx ADS machine description 4452Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 4453[snip] 4454 4455 4456More About U-Boot Image Types: 4457------------------------------ 4458 4459U-Boot supports the following image types: 4460 4461 "Standalone Programs" are directly runnable in the environment 4462 provided by U-Boot; it is expected that (if they behave 4463 well) you can continue to work in U-Boot after return from 4464 the Standalone Program. 4465 "OS Kernel Images" are usually images of some Embedded OS which 4466 will take over control completely. Usually these programs 4467 will install their own set of exception handlers, device 4468 drivers, set up the MMU, etc. - this means, that you cannot 4469 expect to re-enter U-Boot except by resetting the CPU. 4470 "RAMDisk Images" are more or less just data blocks, and their 4471 parameters (address, size) are passed to an OS kernel that is 4472 being started. 4473 "Multi-File Images" contain several images, typically an OS 4474 (Linux) kernel image and one or more data images like 4475 RAMDisks. This construct is useful for instance when you want 4476 to boot over the network using BOOTP etc., where the boot 4477 server provides just a single image file, but you want to get 4478 for instance an OS kernel and a RAMDisk image. 4479 4480 "Multi-File Images" start with a list of image sizes, each 4481 image size (in bytes) specified by an "uint32_t" in network 4482 byte order. This list is terminated by an "(uint32_t)0". 4483 Immediately after the terminating 0 follow the images, one by 4484 one, all aligned on "uint32_t" boundaries (size rounded up to 4485 a multiple of 4 bytes). 4486 4487 "Firmware Images" are binary images containing firmware (like 4488 U-Boot or FPGA images) which usually will be programmed to 4489 flash memory. 4490 4491 "Script files" are command sequences that will be executed by 4492 U-Boot's command interpreter; this feature is especially 4493 useful when you configure U-Boot to use a real shell (hush) 4494 as command interpreter. 4495 4496Booting the Linux zImage: 4497------------------------- 4498 4499On some platforms, it's possible to boot Linux zImage. This is done 4500using the "bootz" command. The syntax of "bootz" command is the same 4501as the syntax of "bootm" command. 4502 4503Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4504kernel with raw initrd images. The syntax is slightly different, the 4505address of the initrd must be augmented by it's size, in the following 4506format: "<initrd addres>:<initrd size>". 4507 4508 4509Standalone HOWTO: 4510================= 4511 4512One of the features of U-Boot is that you can dynamically load and 4513run "standalone" applications, which can use some resources of 4514U-Boot like console I/O functions or interrupt services. 4515 4516Two simple examples are included with the sources: 4517 4518"Hello World" Demo: 4519------------------- 4520 4521'examples/hello_world.c' contains a small "Hello World" Demo 4522application; it is automatically compiled when you build U-Boot. 4523It's configured to run at address 0x00040004, so you can play with it 4524like that: 4525 4526 => loads 4527 ## Ready for S-Record download ... 4528 ~>examples/hello_world.srec 4529 1 2 3 4 5 6 7 8 9 10 11 ... 4530 [file transfer complete] 4531 [connected] 4532 ## Start Addr = 0x00040004 4533 4534 => go 40004 Hello World! This is a test. 4535 ## Starting application at 0x00040004 ... 4536 Hello World 4537 argc = 7 4538 argv[0] = "40004" 4539 argv[1] = "Hello" 4540 argv[2] = "World!" 4541 argv[3] = "This" 4542 argv[4] = "is" 4543 argv[5] = "a" 4544 argv[6] = "test." 4545 argv[7] = "<NULL>" 4546 Hit any key to exit ... 4547 4548 ## Application terminated, rc = 0x0 4549 4550Another example, which demonstrates how to register a CPM interrupt 4551handler with the U-Boot code, can be found in 'examples/timer.c'. 4552Here, a CPM timer is set up to generate an interrupt every second. 4553The interrupt service routine is trivial, just printing a '.' 4554character, but this is just a demo program. The application can be 4555controlled by the following keys: 4556 4557 ? - print current values og the CPM Timer registers 4558 b - enable interrupts and start timer 4559 e - stop timer and disable interrupts 4560 q - quit application 4561 4562 => loads 4563 ## Ready for S-Record download ... 4564 ~>examples/timer.srec 4565 1 2 3 4 5 6 7 8 9 10 11 ... 4566 [file transfer complete] 4567 [connected] 4568 ## Start Addr = 0x00040004 4569 4570 => go 40004 4571 ## Starting application at 0x00040004 ... 4572 TIMERS=0xfff00980 4573 Using timer 1 4574 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4575 4576Hit 'b': 4577 [q, b, e, ?] Set interval 1000000 us 4578 Enabling timer 4579Hit '?': 4580 [q, b, e, ?] ........ 4581 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4582Hit '?': 4583 [q, b, e, ?] . 4584 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4585Hit '?': 4586 [q, b, e, ?] . 4587 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4588Hit '?': 4589 [q, b, e, ?] . 4590 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4591Hit 'e': 4592 [q, b, e, ?] ...Stopping timer 4593Hit 'q': 4594 [q, b, e, ?] ## Application terminated, rc = 0x0 4595 4596 4597Minicom warning: 4598================ 4599 4600Over time, many people have reported problems when trying to use the 4601"minicom" terminal emulation program for serial download. I (wd) 4602consider minicom to be broken, and recommend not to use it. Under 4603Unix, I recommend to use C-Kermit for general purpose use (and 4604especially for kermit binary protocol download ("loadb" command), and 4605use "cu" for S-Record download ("loads" command). See 4606http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4607for help with kermit. 4608 4609 4610Nevertheless, if you absolutely want to use it try adding this 4611configuration to your "File transfer protocols" section: 4612 4613 Name Program Name U/D FullScr IO-Red. Multi 4614 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4615 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4616 4617 4618NetBSD Notes: 4619============= 4620 4621Starting at version 0.9.2, U-Boot supports NetBSD both as host 4622(build U-Boot) and target system (boots NetBSD/mpc8xx). 4623 4624Building requires a cross environment; it is known to work on 4625NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4626need gmake since the Makefiles are not compatible with BSD make). 4627Note that the cross-powerpc package does not install include files; 4628attempting to build U-Boot will fail because <machine/ansi.h> is 4629missing. This file has to be installed and patched manually: 4630 4631 # cd /usr/pkg/cross/powerpc-netbsd/include 4632 # mkdir powerpc 4633 # ln -s powerpc machine 4634 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4635 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4636 4637Native builds *don't* work due to incompatibilities between native 4638and U-Boot include files. 4639 4640Booting assumes that (the first part of) the image booted is a 4641stage-2 loader which in turn loads and then invokes the kernel 4642proper. Loader sources will eventually appear in the NetBSD source 4643tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4644meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4645 4646 4647Implementation Internals: 4648========================= 4649 4650The following is not intended to be a complete description of every 4651implementation detail. However, it should help to understand the 4652inner workings of U-Boot and make it easier to port it to custom 4653hardware. 4654 4655 4656Initial Stack, Global Data: 4657--------------------------- 4658 4659The implementation of U-Boot is complicated by the fact that U-Boot 4660starts running out of ROM (flash memory), usually without access to 4661system RAM (because the memory controller is not initialized yet). 4662This means that we don't have writable Data or BSS segments, and BSS 4663is not initialized as zero. To be able to get a C environment working 4664at all, we have to allocate at least a minimal stack. Implementation 4665options for this are defined and restricted by the CPU used: Some CPU 4666models provide on-chip memory (like the IMMR area on MPC8xx and 4667MPC826x processors), on others (parts of) the data cache can be 4668locked as (mis-) used as memory, etc. 4669 4670 Chris Hallinan posted a good summary of these issues to the 4671 U-Boot mailing list: 4672 4673 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4674 From: "Chris Hallinan" <clh@net1plus.com> 4675 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4676 ... 4677 4678 Correct me if I'm wrong, folks, but the way I understand it 4679 is this: Using DCACHE as initial RAM for Stack, etc, does not 4680 require any physical RAM backing up the cache. The cleverness 4681 is that the cache is being used as a temporary supply of 4682 necessary storage before the SDRAM controller is setup. It's 4683 beyond the scope of this list to explain the details, but you 4684 can see how this works by studying the cache architecture and 4685 operation in the architecture and processor-specific manuals. 4686 4687 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4688 is another option for the system designer to use as an 4689 initial stack/RAM area prior to SDRAM being available. Either 4690 option should work for you. Using CS 4 should be fine if your 4691 board designers haven't used it for something that would 4692 cause you grief during the initial boot! It is frequently not 4693 used. 4694 4695 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4696 with your processor/board/system design. The default value 4697 you will find in any recent u-boot distribution in 4698 walnut.h should work for you. I'd set it to a value larger 4699 than your SDRAM module. If you have a 64MB SDRAM module, set 4700 it above 400_0000. Just make sure your board has no resources 4701 that are supposed to respond to that address! That code in 4702 start.S has been around a while and should work as is when 4703 you get the config right. 4704 4705 -Chris Hallinan 4706 DS4.COM, Inc. 4707 4708It is essential to remember this, since it has some impact on the C 4709code for the initialization procedures: 4710 4711* Initialized global data (data segment) is read-only. Do not attempt 4712 to write it. 4713 4714* Do not use any uninitialized global data (or implicitly initialized 4715 as zero data - BSS segment) at all - this is undefined, initiali- 4716 zation is performed later (when relocating to RAM). 4717 4718* Stack space is very limited. Avoid big data buffers or things like 4719 that. 4720 4721Having only the stack as writable memory limits means we cannot use 4722normal global data to share information between the code. But it 4723turned out that the implementation of U-Boot can be greatly 4724simplified by making a global data structure (gd_t) available to all 4725functions. We could pass a pointer to this data as argument to _all_ 4726functions, but this would bloat the code. Instead we use a feature of 4727the GCC compiler (Global Register Variables) to share the data: we 4728place a pointer (gd) to the global data into a register which we 4729reserve for this purpose. 4730 4731When choosing a register for such a purpose we are restricted by the 4732relevant (E)ABI specifications for the current architecture, and by 4733GCC's implementation. 4734 4735For PowerPC, the following registers have specific use: 4736 R1: stack pointer 4737 R2: reserved for system use 4738 R3-R4: parameter passing and return values 4739 R5-R10: parameter passing 4740 R13: small data area pointer 4741 R30: GOT pointer 4742 R31: frame pointer 4743 4744 (U-Boot also uses R12 as internal GOT pointer. r12 4745 is a volatile register so r12 needs to be reset when 4746 going back and forth between asm and C) 4747 4748 ==> U-Boot will use R2 to hold a pointer to the global data 4749 4750 Note: on PPC, we could use a static initializer (since the 4751 address of the global data structure is known at compile time), 4752 but it turned out that reserving a register results in somewhat 4753 smaller code - although the code savings are not that big (on 4754 average for all boards 752 bytes for the whole U-Boot image, 4755 624 text + 127 data). 4756 4757On ARM, the following registers are used: 4758 4759 R0: function argument word/integer result 4760 R1-R3: function argument word 4761 R9: platform specific 4762 R10: stack limit (used only if stack checking is enabled) 4763 R11: argument (frame) pointer 4764 R12: temporary workspace 4765 R13: stack pointer 4766 R14: link register 4767 R15: program counter 4768 4769 ==> U-Boot will use R9 to hold a pointer to the global data 4770 4771 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4772 4773On Nios II, the ABI is documented here: 4774 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4775 4776 ==> U-Boot will use gp to hold a pointer to the global data 4777 4778 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4779 to access small data sections, so gp is free. 4780 4781On NDS32, the following registers are used: 4782 4783 R0-R1: argument/return 4784 R2-R5: argument 4785 R15: temporary register for assembler 4786 R16: trampoline register 4787 R28: frame pointer (FP) 4788 R29: global pointer (GP) 4789 R30: link register (LP) 4790 R31: stack pointer (SP) 4791 PC: program counter (PC) 4792 4793 ==> U-Boot will use R10 to hold a pointer to the global data 4794 4795NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4796or current versions of GCC may "optimize" the code too much. 4797 4798On RISC-V, the following registers are used: 4799 4800 x0: hard-wired zero (zero) 4801 x1: return address (ra) 4802 x2: stack pointer (sp) 4803 x3: global pointer (gp) 4804 x4: thread pointer (tp) 4805 x5: link register (t0) 4806 x8: frame pointer (fp) 4807 x10-x11: arguments/return values (a0-1) 4808 x12-x17: arguments (a2-7) 4809 x28-31: temporaries (t3-6) 4810 pc: program counter (pc) 4811 4812 ==> U-Boot will use gp to hold a pointer to the global data 4813 4814Memory Management: 4815------------------ 4816 4817U-Boot runs in system state and uses physical addresses, i.e. the 4818MMU is not used either for address mapping nor for memory protection. 4819 4820The available memory is mapped to fixed addresses using the memory 4821controller. In this process, a contiguous block is formed for each 4822memory type (Flash, SDRAM, SRAM), even when it consists of several 4823physical memory banks. 4824 4825U-Boot is installed in the first 128 kB of the first Flash bank (on 4826TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4827booting and sizing and initializing DRAM, the code relocates itself 4828to the upper end of DRAM. Immediately below the U-Boot code some 4829memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4830configuration setting]. Below that, a structure with global Board 4831Info data is placed, followed by the stack (growing downward). 4832 4833Additionally, some exception handler code is copied to the low 8 kB 4834of DRAM (0x00000000 ... 0x00001FFF). 4835 4836So a typical memory configuration with 16 MB of DRAM could look like 4837this: 4838 4839 0x0000 0000 Exception Vector code 4840 : 4841 0x0000 1FFF 4842 0x0000 2000 Free for Application Use 4843 : 4844 : 4845 4846 : 4847 : 4848 0x00FB FF20 Monitor Stack (Growing downward) 4849 0x00FB FFAC Board Info Data and permanent copy of global data 4850 0x00FC 0000 Malloc Arena 4851 : 4852 0x00FD FFFF 4853 0x00FE 0000 RAM Copy of Monitor Code 4854 ... eventually: LCD or video framebuffer 4855 ... eventually: pRAM (Protected RAM - unchanged by reset) 4856 0x00FF FFFF [End of RAM] 4857 4858 4859System Initialization: 4860---------------------- 4861 4862In the reset configuration, U-Boot starts at the reset entry point 4863(on most PowerPC systems at address 0x00000100). Because of the reset 4864configuration for CS0# this is a mirror of the on board Flash memory. 4865To be able to re-map memory U-Boot then jumps to its link address. 4866To be able to implement the initialization code in C, a (small!) 4867initial stack is set up in the internal Dual Ported RAM (in case CPUs 4868which provide such a feature like), or in a locked part of the data 4869cache. After that, U-Boot initializes the CPU core, the caches and 4870the SIU. 4871 4872Next, all (potentially) available memory banks are mapped using a 4873preliminary mapping. For example, we put them on 512 MB boundaries 4874(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4875on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4876programmed for SDRAM access. Using the temporary configuration, a 4877simple memory test is run that determines the size of the SDRAM 4878banks. 4879 4880When there is more than one SDRAM bank, and the banks are of 4881different size, the largest is mapped first. For equal size, the first 4882bank (CS2#) is mapped first. The first mapping is always for address 48830x00000000, with any additional banks following immediately to create 4884contiguous memory starting from 0. 4885 4886Then, the monitor installs itself at the upper end of the SDRAM area 4887and allocates memory for use by malloc() and for the global Board 4888Info data; also, the exception vector code is copied to the low RAM 4889pages, and the final stack is set up. 4890 4891Only after this relocation will you have a "normal" C environment; 4892until that you are restricted in several ways, mostly because you are 4893running from ROM, and because the code will have to be relocated to a 4894new address in RAM. 4895 4896 4897U-Boot Porting Guide: 4898---------------------- 4899 4900[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4901list, October 2002] 4902 4903 4904int main(int argc, char *argv[]) 4905{ 4906 sighandler_t no_more_time; 4907 4908 signal(SIGALRM, no_more_time); 4909 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4910 4911 if (available_money > available_manpower) { 4912 Pay consultant to port U-Boot; 4913 return 0; 4914 } 4915 4916 Download latest U-Boot source; 4917 4918 Subscribe to u-boot mailing list; 4919 4920 if (clueless) 4921 email("Hi, I am new to U-Boot, how do I get started?"); 4922 4923 while (learning) { 4924 Read the README file in the top level directory; 4925 Read http://www.denx.de/twiki/bin/view/DULG/Manual; 4926 Read applicable doc/*.README; 4927 Read the source, Luke; 4928 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4929 } 4930 4931 if (available_money > toLocalCurrency ($2500)) 4932 Buy a BDI3000; 4933 else 4934 Add a lot of aggravation and time; 4935 4936 if (a similar board exists) { /* hopefully... */ 4937 cp -a board/<similar> board/<myboard> 4938 cp include/configs/<similar>.h include/configs/<myboard>.h 4939 } else { 4940 Create your own board support subdirectory; 4941 Create your own board include/configs/<myboard>.h file; 4942 } 4943 Edit new board/<myboard> files 4944 Edit new include/configs/<myboard>.h 4945 4946 while (!accepted) { 4947 while (!running) { 4948 do { 4949 Add / modify source code; 4950 } until (compiles); 4951 Debug; 4952 if (clueless) 4953 email("Hi, I am having problems..."); 4954 } 4955 Send patch file to the U-Boot email list; 4956 if (reasonable critiques) 4957 Incorporate improvements from email list code review; 4958 else 4959 Defend code as written; 4960 } 4961 4962 return 0; 4963} 4964 4965void no_more_time (int sig) 4966{ 4967 hire_a_guru(); 4968} 4969 4970 4971Coding Standards: 4972----------------- 4973 4974All contributions to U-Boot should conform to the Linux kernel 4975coding style; see the kernel coding style guide at 4976https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4977script "scripts/Lindent" in your Linux kernel source directory. 4978 4979Source files originating from a different project (for example the 4980MTD subsystem) are generally exempt from these guidelines and are not 4981reformatted to ease subsequent migration to newer versions of those 4982sources. 4983 4984Please note that U-Boot is implemented in C (and to some small parts in 4985Assembler); no C++ is used, so please do not use C++ style comments (//) 4986in your code. 4987 4988Please also stick to the following formatting rules: 4989- remove any trailing white space 4990- use TAB characters for indentation and vertical alignment, not spaces 4991- make sure NOT to use DOS '\r\n' line feeds 4992- do not add more than 2 consecutive empty lines to source files 4993- do not add trailing empty lines to source files 4994 4995Submissions which do not conform to the standards may be returned 4996with a request to reformat the changes. 4997 4998 4999Submitting Patches: 5000------------------- 5001 5002Since the number of patches for U-Boot is growing, we need to 5003establish some rules. Submissions which do not conform to these rules 5004may be rejected, even when they contain important and valuable stuff. 5005 5006Please see http://www.denx.de/wiki/U-Boot/Patches for details. 5007 5008Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 5009see https://lists.denx.de/listinfo/u-boot 5010 5011When you send a patch, please include the following information with 5012it: 5013 5014* For bug fixes: a description of the bug and how your patch fixes 5015 this bug. Please try to include a way of demonstrating that the 5016 patch actually fixes something. 5017 5018* For new features: a description of the feature and your 5019 implementation. 5020 5021* A CHANGELOG entry as plaintext (separate from the patch) 5022 5023* For major contributions, add a MAINTAINERS file with your 5024 information and associated file and directory references. 5025 5026* When you add support for a new board, don't forget to add a 5027 maintainer e-mail address to the boards.cfg file, too. 5028 5029* If your patch adds new configuration options, don't forget to 5030 document these in the README file. 5031 5032* The patch itself. If you are using git (which is *strongly* 5033 recommended) you can easily generate the patch using the 5034 "git format-patch". If you then use "git send-email" to send it to 5035 the U-Boot mailing list, you will avoid most of the common problems 5036 with some other mail clients. 5037 5038 If you cannot use git, use "diff -purN OLD NEW". If your version of 5039 diff does not support these options, then get the latest version of 5040 GNU diff. 5041 5042 The current directory when running this command shall be the parent 5043 directory of the U-Boot source tree (i. e. please make sure that 5044 your patch includes sufficient directory information for the 5045 affected files). 5046 5047 We prefer patches as plain text. MIME attachments are discouraged, 5048 and compressed attachments must not be used. 5049 5050* If one logical set of modifications affects or creates several 5051 files, all these changes shall be submitted in a SINGLE patch file. 5052 5053* Changesets that contain different, unrelated modifications shall be 5054 submitted as SEPARATE patches, one patch per changeset. 5055 5056 5057Notes: 5058 5059* Before sending the patch, run the buildman script on your patched 5060 source tree and make sure that no errors or warnings are reported 5061 for any of the boards. 5062 5063* Keep your modifications to the necessary minimum: A patch 5064 containing several unrelated changes or arbitrary reformats will be 5065 returned with a request to re-formatting / split it. 5066 5067* If you modify existing code, make sure that your new code does not 5068 add to the memory footprint of the code ;-) Small is beautiful! 5069 When adding new features, these should compile conditionally only 5070 (using #ifdef), and the resulting code with the new feature 5071 disabled must not need more memory than the old code without your 5072 modification. 5073 5074* Remember that there is a size limit of 100 kB per message on the 5075 u-boot mailing list. Bigger patches will be moderated. If they are 5076 reasonable and not too big, they will be acknowledged. But patches 5077 bigger than the size limit should be avoided. 5078