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_DRIVER_TI_EMAC 981 Support for davinci emac 982 983 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 984 Define this if you have more then 3 PHYs. 985 986 CONFIG_FTGMAC100 987 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 988 989 CONFIG_FTGMAC100_EGIGA 990 Define this to use GE link update with gigabit PHY. 991 Define this if FTGMAC100 is connected to gigabit PHY. 992 If your system has 10/100 PHY only, it might not occur 993 wrong behavior. Because PHY usually return timeout or 994 useless data when polling gigabit status and gigabit 995 control registers. This behavior won't affect the 996 correctnessof 10/100 link speed update. 997 998 CONFIG_SH_ETHER 999 Support for Renesas on-chip Ethernet controller 1000 1001 CONFIG_SH_ETHER_USE_PORT 1002 Define the number of ports to be used 1003 1004 CONFIG_SH_ETHER_PHY_ADDR 1005 Define the ETH PHY's address 1006 1007 CONFIG_SH_ETHER_CACHE_WRITEBACK 1008 If this option is set, the driver enables cache flush. 1009 1010- PWM Support: 1011 CONFIG_PWM_IMX 1012 Support for PWM module on the imx6. 1013 1014- TPM Support: 1015 CONFIG_TPM 1016 Support TPM devices. 1017 1018 CONFIG_TPM_TIS_INFINEON 1019 Support for Infineon i2c bus TPM devices. Only one device 1020 per system is supported at this time. 1021 1022 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 1023 Define the burst count bytes upper limit 1024 1025 CONFIG_TPM_ST33ZP24 1026 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 1027 1028 CONFIG_TPM_ST33ZP24_I2C 1029 Support for STMicroelectronics ST33ZP24 I2C devices. 1030 Requires TPM_ST33ZP24 and I2C. 1031 1032 CONFIG_TPM_ST33ZP24_SPI 1033 Support for STMicroelectronics ST33ZP24 SPI devices. 1034 Requires TPM_ST33ZP24 and SPI. 1035 1036 CONFIG_TPM_ATMEL_TWI 1037 Support for Atmel TWI TPM device. Requires I2C support. 1038 1039 CONFIG_TPM_TIS_LPC 1040 Support for generic parallel port TPM devices. Only one device 1041 per system is supported at this time. 1042 1043 CONFIG_TPM_TIS_BASE_ADDRESS 1044 Base address where the generic TPM device is mapped 1045 to. Contemporary x86 systems usually map it at 1046 0xfed40000. 1047 1048 CONFIG_TPM 1049 Define this to enable the TPM support library which provides 1050 functional interfaces to some TPM commands. 1051 Requires support for a TPM device. 1052 1053 CONFIG_TPM_AUTH_SESSIONS 1054 Define this to enable authorized functions in the TPM library. 1055 Requires CONFIG_TPM and CONFIG_SHA1. 1056 1057- USB Support: 1058 At the moment only the UHCI host controller is 1059 supported (PIP405, MIP405); define 1060 CONFIG_USB_UHCI to enable it. 1061 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 1062 and define CONFIG_USB_STORAGE to enable the USB 1063 storage devices. 1064 Note: 1065 Supported are USB Keyboards and USB Floppy drives 1066 (TEAC FD-05PUB). 1067 1068 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 1069 txfilltuning field in the EHCI controller on reset. 1070 1071 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2 1072 HW module registers. 1073 1074- USB Device: 1075 Define the below if you wish to use the USB console. 1076 Once firmware is rebuilt from a serial console issue the 1077 command "setenv stdin usbtty; setenv stdout usbtty" and 1078 attach your USB cable. The Unix command "dmesg" should print 1079 it has found a new device. The environment variable usbtty 1080 can be set to gserial or cdc_acm to enable your device to 1081 appear to a USB host as a Linux gserial device or a 1082 Common Device Class Abstract Control Model serial device. 1083 If you select usbtty = gserial you should be able to enumerate 1084 a Linux host by 1085 # modprobe usbserial vendor=0xVendorID product=0xProductID 1086 else if using cdc_acm, simply setting the environment 1087 variable usbtty to be cdc_acm should suffice. The following 1088 might be defined in YourBoardName.h 1089 1090 CONFIG_USB_DEVICE 1091 Define this to build a UDC device 1092 1093 CONFIG_USB_TTY 1094 Define this to have a tty type of device available to 1095 talk to the UDC device 1096 1097 CONFIG_USBD_HS 1098 Define this to enable the high speed support for usb 1099 device and usbtty. If this feature is enabled, a routine 1100 int is_usbd_high_speed(void) 1101 also needs to be defined by the driver to dynamically poll 1102 whether the enumeration has succeded at high speed or full 1103 speed. 1104 1105 CONFIG_SYS_CONSOLE_IS_IN_ENV 1106 Define this if you want stdin, stdout &/or stderr to 1107 be set to usbtty. 1108 1109 If you have a USB-IF assigned VendorID then you may wish to 1110 define your own vendor specific values either in BoardName.h 1111 or directly in usbd_vendor_info.h. If you don't define 1112 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 1113 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 1114 should pretend to be a Linux device to it's target host. 1115 1116 CONFIG_USBD_MANUFACTURER 1117 Define this string as the name of your company for 1118 - CONFIG_USBD_MANUFACTURER "my company" 1119 1120 CONFIG_USBD_PRODUCT_NAME 1121 Define this string as the name of your product 1122 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 1123 1124 CONFIG_USBD_VENDORID 1125 Define this as your assigned Vendor ID from the USB 1126 Implementors Forum. This *must* be a genuine Vendor ID 1127 to avoid polluting the USB namespace. 1128 - CONFIG_USBD_VENDORID 0xFFFF 1129 1130 CONFIG_USBD_PRODUCTID 1131 Define this as the unique Product ID 1132 for your device 1133 - CONFIG_USBD_PRODUCTID 0xFFFF 1134 1135- ULPI Layer Support: 1136 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 1137 the generic ULPI layer. The generic layer accesses the ULPI PHY 1138 via the platform viewport, so you need both the genric layer and 1139 the viewport enabled. Currently only Chipidea/ARC based 1140 viewport is supported. 1141 To enable the ULPI layer support, define CONFIG_USB_ULPI and 1142 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 1143 If your ULPI phy needs a different reference clock than the 1144 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 1145 the appropriate value in Hz. 1146 1147- MMC Support: 1148 The MMC controller on the Intel PXA is supported. To 1149 enable this define CONFIG_MMC. The MMC can be 1150 accessed from the boot prompt by mapping the device 1151 to physical memory similar to flash. Command line is 1152 enabled with CONFIG_CMD_MMC. The MMC driver also works with 1153 the FAT fs. This is enabled with CONFIG_CMD_FAT. 1154 1155 CONFIG_SH_MMCIF 1156 Support for Renesas on-chip MMCIF controller 1157 1158 CONFIG_SH_MMCIF_ADDR 1159 Define the base address of MMCIF registers 1160 1161 CONFIG_SH_MMCIF_CLK 1162 Define the clock frequency for MMCIF 1163 1164 CONFIG_SUPPORT_EMMC_BOOT 1165 Enable some additional features of the eMMC boot partitions. 1166 1167- USB Device Firmware Update (DFU) class support: 1168 CONFIG_DFU_OVER_USB 1169 This enables the USB portion of the DFU USB class 1170 1171 CONFIG_DFU_MMC 1172 This enables support for exposing (e)MMC devices via DFU. 1173 1174 CONFIG_DFU_NAND 1175 This enables support for exposing NAND devices via DFU. 1176 1177 CONFIG_DFU_RAM 1178 This enables support for exposing RAM via DFU. 1179 Note: DFU spec refer to non-volatile memory usage, but 1180 allow usages beyond the scope of spec - here RAM usage, 1181 one that would help mostly the developer. 1182 1183 CONFIG_SYS_DFU_DATA_BUF_SIZE 1184 Dfu transfer uses a buffer before writing data to the 1185 raw storage device. Make the size (in bytes) of this buffer 1186 configurable. The size of this buffer is also configurable 1187 through the "dfu_bufsiz" environment variable. 1188 1189 CONFIG_SYS_DFU_MAX_FILE_SIZE 1190 When updating files rather than the raw storage device, 1191 we use a static buffer to copy the file into and then write 1192 the buffer once we've been given the whole file. Define 1193 this to the maximum filesize (in bytes) for the buffer. 1194 Default is 4 MiB if undefined. 1195 1196 DFU_DEFAULT_POLL_TIMEOUT 1197 Poll timeout [ms], is the timeout a device can send to the 1198 host. The host must wait for this timeout before sending 1199 a subsequent DFU_GET_STATUS request to the device. 1200 1201 DFU_MANIFEST_POLL_TIMEOUT 1202 Poll timeout [ms], which the device sends to the host when 1203 entering dfuMANIFEST state. Host waits this timeout, before 1204 sending again an USB request to the device. 1205 1206- Journaling Flash filesystem support: 1207 CONFIG_JFFS2_NAND 1208 Define these for a default partition on a NAND device 1209 1210 CONFIG_SYS_JFFS2_FIRST_SECTOR, 1211 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 1212 Define these for a default partition on a NOR device 1213 1214- Keyboard Support: 1215 See Kconfig help for available keyboard drivers. 1216 1217 CONFIG_KEYBOARD 1218 1219 Define this to enable a custom keyboard support. 1220 This simply calls drv_keyboard_init() which must be 1221 defined in your board-specific files. This option is deprecated 1222 and is only used by novena. For new boards, use driver model 1223 instead. 1224 1225- Video support: 1226 CONFIG_FSL_DIU_FB 1227 Enable the Freescale DIU video driver. Reference boards for 1228 SOCs that have a DIU should define this macro to enable DIU 1229 support, and should also define these other macros: 1230 1231 CONFIG_SYS_DIU_ADDR 1232 CONFIG_VIDEO 1233 CONFIG_CFB_CONSOLE 1234 CONFIG_VIDEO_SW_CURSOR 1235 CONFIG_VGA_AS_SINGLE_DEVICE 1236 CONFIG_VIDEO_LOGO 1237 CONFIG_VIDEO_BMP_LOGO 1238 1239 The DIU driver will look for the 'video-mode' environment 1240 variable, and if defined, enable the DIU as a console during 1241 boot. See the documentation file doc/README.video for a 1242 description of this variable. 1243 1244- LCD Support: CONFIG_LCD 1245 1246 Define this to enable LCD support (for output to LCD 1247 display); also select one of the supported displays 1248 by defining one of these: 1249 1250 CONFIG_ATMEL_LCD: 1251 1252 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1253 1254 CONFIG_NEC_NL6448AC33: 1255 1256 NEC NL6448AC33-18. Active, color, single scan. 1257 1258 CONFIG_NEC_NL6448BC20 1259 1260 NEC NL6448BC20-08. 6.5", 640x480. 1261 Active, color, single scan. 1262 1263 CONFIG_NEC_NL6448BC33_54 1264 1265 NEC NL6448BC33-54. 10.4", 640x480. 1266 Active, color, single scan. 1267 1268 CONFIG_SHARP_16x9 1269 1270 Sharp 320x240. Active, color, single scan. 1271 It isn't 16x9, and I am not sure what it is. 1272 1273 CONFIG_SHARP_LQ64D341 1274 1275 Sharp LQ64D341 display, 640x480. 1276 Active, color, single scan. 1277 1278 CONFIG_HLD1045 1279 1280 HLD1045 display, 640x480. 1281 Active, color, single scan. 1282 1283 CONFIG_OPTREX_BW 1284 1285 Optrex CBL50840-2 NF-FW 99 22 M5 1286 or 1287 Hitachi LMG6912RPFC-00T 1288 or 1289 Hitachi SP14Q002 1290 1291 320x240. Black & white. 1292 1293 CONFIG_LCD_ALIGNMENT 1294 1295 Normally the LCD is page-aligned (typically 4KB). If this is 1296 defined then the LCD will be aligned to this value instead. 1297 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1298 here, since it is cheaper to change data cache settings on 1299 a per-section basis. 1300 1301 1302 CONFIG_LCD_ROTATION 1303 1304 Sometimes, for example if the display is mounted in portrait 1305 mode or even if it's mounted landscape but rotated by 180degree, 1306 we need to rotate our content of the display relative to the 1307 framebuffer, so that user can read the messages which are 1308 printed out. 1309 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1310 initialized with a given rotation from "vl_rot" out of 1311 "vidinfo_t" which is provided by the board specific code. 1312 The value for vl_rot is coded as following (matching to 1313 fbcon=rotate:<n> linux-kernel commandline): 1314 0 = no rotation respectively 0 degree 1315 1 = 90 degree rotation 1316 2 = 180 degree rotation 1317 3 = 270 degree rotation 1318 1319 If CONFIG_LCD_ROTATION is not defined, the console will be 1320 initialized with 0degree rotation. 1321 1322 CONFIG_LCD_BMP_RLE8 1323 1324 Support drawing of RLE8-compressed bitmaps on the LCD. 1325 1326 CONFIG_I2C_EDID 1327 1328 Enables an 'i2c edid' command which can read EDID 1329 information over I2C from an attached LCD display. 1330 1331- Splash Screen Support: CONFIG_SPLASH_SCREEN 1332 1333 If this option is set, the environment is checked for 1334 a variable "splashimage". If found, the usual display 1335 of logo, copyright and system information on the LCD 1336 is suppressed and the BMP image at the address 1337 specified in "splashimage" is loaded instead. The 1338 console is redirected to the "nulldev", too. This 1339 allows for a "silent" boot where a splash screen is 1340 loaded very quickly after power-on. 1341 1342 CONFIG_SPLASHIMAGE_GUARD 1343 1344 If this option is set, then U-Boot will prevent the environment 1345 variable "splashimage" from being set to a problematic address 1346 (see doc/README.displaying-bmps). 1347 This option is useful for targets where, due to alignment 1348 restrictions, an improperly aligned BMP image will cause a data 1349 abort. If you think you will not have problems with unaligned 1350 accesses (for example because your toolchain prevents them) 1351 there is no need to set this option. 1352 1353 CONFIG_SPLASH_SCREEN_ALIGN 1354 1355 If this option is set the splash image can be freely positioned 1356 on the screen. Environment variable "splashpos" specifies the 1357 position as "x,y". If a positive number is given it is used as 1358 number of pixel from left/top. If a negative number is given it 1359 is used as number of pixel from right/bottom. You can also 1360 specify 'm' for centering the image. 1361 1362 Example: 1363 setenv splashpos m,m 1364 => image at center of screen 1365 1366 setenv splashpos 30,20 1367 => image at x = 30 and y = 20 1368 1369 setenv splashpos -10,m 1370 => vertically centered image 1371 at x = dspWidth - bmpWidth - 9 1372 1373- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP 1374 1375 If this option is set, additionally to standard BMP 1376 images, gzipped BMP images can be displayed via the 1377 splashscreen support or the bmp command. 1378 1379- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8 1380 1381 If this option is set, 8-bit RLE compressed BMP images 1382 can be displayed via the splashscreen support or the 1383 bmp command. 1384 1385- Compression support: 1386 CONFIG_GZIP 1387 1388 Enabled by default to support gzip compressed images. 1389 1390 CONFIG_BZIP2 1391 1392 If this option is set, support for bzip2 compressed 1393 images is included. If not, only uncompressed and gzip 1394 compressed images are supported. 1395 1396 NOTE: the bzip2 algorithm requires a lot of RAM, so 1397 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should 1398 be at least 4MB. 1399 1400- MII/PHY support: 1401 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1402 1403 The clock frequency of the MII bus 1404 1405 CONFIG_PHY_RESET_DELAY 1406 1407 Some PHY like Intel LXT971A need extra delay after 1408 reset before any MII register access is possible. 1409 For such PHY, set this option to the usec delay 1410 required. (minimum 300usec for LXT971A) 1411 1412 CONFIG_PHY_CMD_DELAY (ppc4xx) 1413 1414 Some PHY like Intel LXT971A need extra delay after 1415 command issued before MII status register can be read 1416 1417- IP address: 1418 CONFIG_IPADDR 1419 1420 Define a default value for the IP address to use for 1421 the default Ethernet interface, in case this is not 1422 determined through e.g. bootp. 1423 (Environment variable "ipaddr") 1424 1425- Server IP address: 1426 CONFIG_SERVERIP 1427 1428 Defines a default value for the IP address of a TFTP 1429 server to contact when using the "tftboot" command. 1430 (Environment variable "serverip") 1431 1432 CONFIG_KEEP_SERVERADDR 1433 1434 Keeps the server's MAC address, in the env 'serveraddr' 1435 for passing to bootargs (like Linux's netconsole option) 1436 1437- Gateway IP address: 1438 CONFIG_GATEWAYIP 1439 1440 Defines a default value for the IP address of the 1441 default router where packets to other networks are 1442 sent to. 1443 (Environment variable "gatewayip") 1444 1445- Subnet mask: 1446 CONFIG_NETMASK 1447 1448 Defines a default value for the subnet mask (or 1449 routing prefix) which is used to determine if an IP 1450 address belongs to the local subnet or needs to be 1451 forwarded through a router. 1452 (Environment variable "netmask") 1453 1454- Multicast TFTP Mode: 1455 CONFIG_MCAST_TFTP 1456 1457 Defines whether you want to support multicast TFTP as per 1458 rfc-2090; for example to work with atftp. Lets lots of targets 1459 tftp down the same boot image concurrently. Note: the Ethernet 1460 driver in use must provide a function: mcast() to join/leave a 1461 multicast group. 1462 1463- BOOTP Recovery Mode: 1464 CONFIG_BOOTP_RANDOM_DELAY 1465 1466 If you have many targets in a network that try to 1467 boot using BOOTP, you may want to avoid that all 1468 systems send out BOOTP requests at precisely the same 1469 moment (which would happen for instance at recovery 1470 from a power failure, when all systems will try to 1471 boot, thus flooding the BOOTP server. Defining 1472 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1473 inserted before sending out BOOTP requests. The 1474 following delays are inserted then: 1475 1476 1st BOOTP request: delay 0 ... 1 sec 1477 2nd BOOTP request: delay 0 ... 2 sec 1478 3rd BOOTP request: delay 0 ... 4 sec 1479 4th and following 1480 BOOTP requests: delay 0 ... 8 sec 1481 1482 CONFIG_BOOTP_ID_CACHE_SIZE 1483 1484 BOOTP packets are uniquely identified using a 32-bit ID. The 1485 server will copy the ID from client requests to responses and 1486 U-Boot will use this to determine if it is the destination of 1487 an incoming response. Some servers will check that addresses 1488 aren't in use before handing them out (usually using an ARP 1489 ping) and therefore take up to a few hundred milliseconds to 1490 respond. Network congestion may also influence the time it 1491 takes for a response to make it back to the client. If that 1492 time is too long, U-Boot will retransmit requests. In order 1493 to allow earlier responses to still be accepted after these 1494 retransmissions, U-Boot's BOOTP client keeps a small cache of 1495 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1496 cache. The default is to keep IDs for up to four outstanding 1497 requests. Increasing this will allow U-Boot to accept offers 1498 from a BOOTP client in networks with unusually high latency. 1499 1500- DHCP Advanced Options: 1501 You can fine tune the DHCP functionality by defining 1502 CONFIG_BOOTP_* symbols: 1503 1504 CONFIG_BOOTP_NISDOMAIN 1505 CONFIG_BOOTP_BOOTFILESIZE 1506 CONFIG_BOOTP_SEND_HOSTNAME 1507 CONFIG_BOOTP_NTPSERVER 1508 CONFIG_BOOTP_TIMEOFFSET 1509 CONFIG_BOOTP_VENDOREX 1510 CONFIG_BOOTP_MAY_FAIL 1511 1512 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1513 environment variable, not the BOOTP server. 1514 1515 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1516 after the configured retry count, the call will fail 1517 instead of starting over. This can be used to fail over 1518 to Link-local IP address configuration if the DHCP server 1519 is not available. 1520 1521 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1522 to do a dynamic update of a DNS server. To do this, they 1523 need the hostname of the DHCP requester. 1524 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1525 of the "hostname" environment variable is passed as 1526 option 12 to the DHCP server. 1527 1528 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1529 1530 A 32bit value in microseconds for a delay between 1531 receiving a "DHCP Offer" and sending the "DHCP Request". 1532 This fixes a problem with certain DHCP servers that don't 1533 respond 100% of the time to a "DHCP request". E.g. On an 1534 AT91RM9200 processor running at 180MHz, this delay needed 1535 to be *at least* 15,000 usec before a Windows Server 2003 1536 DHCP server would reply 100% of the time. I recommend at 1537 least 50,000 usec to be safe. The alternative is to hope 1538 that one of the retries will be successful but note that 1539 the DHCP timeout and retry process takes a longer than 1540 this delay. 1541 1542 - Link-local IP address negotiation: 1543 Negotiate with other link-local clients on the local network 1544 for an address that doesn't require explicit configuration. 1545 This is especially useful if a DHCP server cannot be guaranteed 1546 to exist in all environments that the device must operate. 1547 1548 See doc/README.link-local for more information. 1549 1550 - MAC address from environment variables 1551 1552 FDT_SEQ_MACADDR_FROM_ENV 1553 1554 Fix-up device tree with MAC addresses fetched sequentially from 1555 environment variables. This config work on assumption that 1556 non-usable ethernet node of device-tree are either not present 1557 or their status has been marked as "disabled". 1558 1559 - CDP Options: 1560 CONFIG_CDP_DEVICE_ID 1561 1562 The device id used in CDP trigger frames. 1563 1564 CONFIG_CDP_DEVICE_ID_PREFIX 1565 1566 A two character string which is prefixed to the MAC address 1567 of the device. 1568 1569 CONFIG_CDP_PORT_ID 1570 1571 A printf format string which contains the ascii name of 1572 the port. Normally is set to "eth%d" which sets 1573 eth0 for the first Ethernet, eth1 for the second etc. 1574 1575 CONFIG_CDP_CAPABILITIES 1576 1577 A 32bit integer which indicates the device capabilities; 1578 0x00000010 for a normal host which does not forwards. 1579 1580 CONFIG_CDP_VERSION 1581 1582 An ascii string containing the version of the software. 1583 1584 CONFIG_CDP_PLATFORM 1585 1586 An ascii string containing the name of the platform. 1587 1588 CONFIG_CDP_TRIGGER 1589 1590 A 32bit integer sent on the trigger. 1591 1592 CONFIG_CDP_POWER_CONSUMPTION 1593 1594 A 16bit integer containing the power consumption of the 1595 device in .1 of milliwatts. 1596 1597 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1598 1599 A byte containing the id of the VLAN. 1600 1601- Status LED: CONFIG_LED_STATUS 1602 1603 Several configurations allow to display the current 1604 status using a LED. For instance, the LED will blink 1605 fast while running U-Boot code, stop blinking as 1606 soon as a reply to a BOOTP request was received, and 1607 start blinking slow once the Linux kernel is running 1608 (supported by a status LED driver in the Linux 1609 kernel). Defining CONFIG_LED_STATUS enables this 1610 feature in U-Boot. 1611 1612 Additional options: 1613 1614 CONFIG_LED_STATUS_GPIO 1615 The status LED can be connected to a GPIO pin. 1616 In such cases, the gpio_led driver can be used as a 1617 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1618 to include the gpio_led driver in the U-Boot binary. 1619 1620 CONFIG_GPIO_LED_INVERTED_TABLE 1621 Some GPIO connected LEDs may have inverted polarity in which 1622 case the GPIO high value corresponds to LED off state and 1623 GPIO low value corresponds to LED on state. 1624 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1625 with a list of GPIO LEDs that have inverted polarity. 1626 1627- I2C Support: CONFIG_SYS_I2C 1628 1629 This enable the NEW i2c subsystem, and will allow you to use 1630 i2c commands at the u-boot command line (as long as you set 1631 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c 1632 based realtime clock chips or other i2c devices. See 1633 common/cmd_i2c.c for a description of the command line 1634 interface. 1635 1636 ported i2c driver to the new framework: 1637 - drivers/i2c/soft_i2c.c: 1638 - activate first bus with CONFIG_SYS_I2C_SOFT define 1639 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1640 for defining speed and slave address 1641 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1642 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1643 for defining speed and slave address 1644 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1645 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1646 for defining speed and slave address 1647 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1648 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1649 for defining speed and slave address 1650 1651 - drivers/i2c/fsl_i2c.c: 1652 - activate i2c driver with CONFIG_SYS_I2C_FSL 1653 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1654 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1655 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1656 bus. 1657 - If your board supports a second fsl i2c bus, define 1658 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1659 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1660 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1661 second bus. 1662 1663 - drivers/i2c/tegra_i2c.c: 1664 - activate this driver with CONFIG_SYS_I2C_TEGRA 1665 - This driver adds 4 i2c buses with a fix speed from 1666 100000 and the slave addr 0! 1667 1668 - drivers/i2c/ppc4xx_i2c.c 1669 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1670 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1671 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1672 1673 - drivers/i2c/i2c_mxc.c 1674 - activate this driver with CONFIG_SYS_I2C_MXC 1675 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1676 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1677 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1678 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1679 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1680 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1681 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1682 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1683 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1684 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1685 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1686 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1687 If those defines are not set, default value is 100000 1688 for speed, and 0 for slave. 1689 1690 - drivers/i2c/rcar_i2c.c: 1691 - activate this driver with CONFIG_SYS_I2C_RCAR 1692 - This driver adds 4 i2c buses 1693 1694 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 1695 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 1696 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 1697 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 1698 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 1699 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 1700 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 1701 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 1702 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses 1703 1704 - drivers/i2c/sh_i2c.c: 1705 - activate this driver with CONFIG_SYS_I2C_SH 1706 - This driver adds from 2 to 5 i2c buses 1707 1708 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1709 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1710 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1711 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1712 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1713 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1714 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1715 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1716 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1717 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1718 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1719 1720 - drivers/i2c/omap24xx_i2c.c 1721 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1722 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1723 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1724 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1725 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1726 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1727 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1728 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1729 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1730 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1731 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1732 1733 - drivers/i2c/zynq_i2c.c 1734 - activate this driver with CONFIG_SYS_I2C_ZYNQ 1735 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting 1736 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr 1737 1738 - drivers/i2c/s3c24x0_i2c.c: 1739 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1740 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1741 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1742 with a fix speed from 100000 and the slave addr 0! 1743 1744 - drivers/i2c/ihs_i2c.c 1745 - activate this driver with CONFIG_SYS_I2C_IHS 1746 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1747 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1748 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1749 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1750 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1751 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1752 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1753 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1754 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1755 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1756 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1757 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1758 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1759 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1760 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1761 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1762 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1763 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1764 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1765 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1766 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1767 1768 additional defines: 1769 1770 CONFIG_SYS_NUM_I2C_BUSES 1771 Hold the number of i2c buses you want to use. 1772 1773 CONFIG_SYS_I2C_DIRECT_BUS 1774 define this, if you don't use i2c muxes on your hardware. 1775 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1776 omit this define. 1777 1778 CONFIG_SYS_I2C_MAX_HOPS 1779 define how many muxes are maximal consecutively connected 1780 on one i2c bus. If you not use i2c muxes, omit this 1781 define. 1782 1783 CONFIG_SYS_I2C_BUSES 1784 hold a list of buses you want to use, only used if 1785 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1786 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1787 CONFIG_SYS_NUM_I2C_BUSES = 9: 1788 1789 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1790 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1791 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1792 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1793 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1794 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1795 {1, {I2C_NULL_HOP}}, \ 1796 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1797 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1798 } 1799 1800 which defines 1801 bus 0 on adapter 0 without a mux 1802 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1803 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1804 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1805 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1806 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1807 bus 6 on adapter 1 without a mux 1808 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1809 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1810 1811 If you do not have i2c muxes on your board, omit this define. 1812 1813- Legacy I2C Support: 1814 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1815 then the following macros need to be defined (examples are 1816 from include/configs/lwmon.h): 1817 1818 I2C_INIT 1819 1820 (Optional). Any commands necessary to enable the I2C 1821 controller or configure ports. 1822 1823 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1824 1825 I2C_ACTIVE 1826 1827 The code necessary to make the I2C data line active 1828 (driven). If the data line is open collector, this 1829 define can be null. 1830 1831 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1832 1833 I2C_TRISTATE 1834 1835 The code necessary to make the I2C data line tri-stated 1836 (inactive). If the data line is open collector, this 1837 define can be null. 1838 1839 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1840 1841 I2C_READ 1842 1843 Code that returns true if the I2C data line is high, 1844 false if it is low. 1845 1846 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1847 1848 I2C_SDA(bit) 1849 1850 If <bit> is true, sets the I2C data line high. If it 1851 is false, it clears it (low). 1852 1853 eg: #define I2C_SDA(bit) \ 1854 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1855 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1856 1857 I2C_SCL(bit) 1858 1859 If <bit> is true, sets the I2C clock line high. If it 1860 is false, it clears it (low). 1861 1862 eg: #define I2C_SCL(bit) \ 1863 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1864 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1865 1866 I2C_DELAY 1867 1868 This delay is invoked four times per clock cycle so this 1869 controls the rate of data transfer. The data rate thus 1870 is 1 / (I2C_DELAY * 4). Often defined to be something 1871 like: 1872 1873 #define I2C_DELAY udelay(2) 1874 1875 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1876 1877 If your arch supports the generic GPIO framework (asm/gpio.h), 1878 then you may alternatively define the two GPIOs that are to be 1879 used as SCL / SDA. Any of the previous I2C_xxx macros will 1880 have GPIO-based defaults assigned to them as appropriate. 1881 1882 You should define these to the GPIO value as given directly to 1883 the generic GPIO functions. 1884 1885 CONFIG_SYS_I2C_INIT_BOARD 1886 1887 When a board is reset during an i2c bus transfer 1888 chips might think that the current transfer is still 1889 in progress. On some boards it is possible to access 1890 the i2c SCLK line directly, either by using the 1891 processor pin as a GPIO or by having a second pin 1892 connected to the bus. If this option is defined a 1893 custom i2c_init_board() routine in boards/xxx/board.c 1894 is run early in the boot sequence. 1895 1896 CONFIG_I2C_MULTI_BUS 1897 1898 This option allows the use of multiple I2C buses, each of which 1899 must have a controller. At any point in time, only one bus is 1900 active. To switch to a different bus, use the 'i2c dev' command. 1901 Note that bus numbering is zero-based. 1902 1903 CONFIG_SYS_I2C_NOPROBES 1904 1905 This option specifies a list of I2C devices that will be skipped 1906 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1907 is set, specify a list of bus-device pairs. Otherwise, specify 1908 a 1D array of device addresses 1909 1910 e.g. 1911 #undef CONFIG_I2C_MULTI_BUS 1912 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1913 1914 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1915 1916 #define CONFIG_I2C_MULTI_BUS 1917 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1918 1919 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1920 1921 CONFIG_SYS_SPD_BUS_NUM 1922 1923 If defined, then this indicates the I2C bus number for DDR SPD. 1924 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1925 1926 CONFIG_SYS_RTC_BUS_NUM 1927 1928 If defined, then this indicates the I2C bus number for the RTC. 1929 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1930 1931 CONFIG_SOFT_I2C_READ_REPEATED_START 1932 1933 defining this will force the i2c_read() function in 1934 the soft_i2c driver to perform an I2C repeated start 1935 between writing the address pointer and reading the 1936 data. If this define is omitted the default behaviour 1937 of doing a stop-start sequence will be used. Most I2C 1938 devices can use either method, but some require one or 1939 the other. 1940 1941- SPI Support: CONFIG_SPI 1942 1943 Enables SPI driver (so far only tested with 1944 SPI EEPROM, also an instance works with Crystal A/D and 1945 D/As on the SACSng board) 1946 1947 CONFIG_SOFT_SPI 1948 1949 Enables a software (bit-bang) SPI driver rather than 1950 using hardware support. This is a general purpose 1951 driver that only requires three general I/O port pins 1952 (two outputs, one input) to function. If this is 1953 defined, the board configuration must define several 1954 SPI configuration items (port pins to use, etc). For 1955 an example, see include/configs/sacsng.h. 1956 1957 CONFIG_HARD_SPI 1958 1959 Enables a hardware SPI driver for general-purpose reads 1960 and writes. As with CONFIG_SOFT_SPI, the board configuration 1961 must define a list of chip-select function pointers. 1962 Currently supported on some MPC8xxx processors. For an 1963 example, see include/configs/mpc8349emds.h. 1964 1965 CONFIG_SYS_SPI_MXC_WAIT 1966 Timeout for waiting until spi transfer completed. 1967 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1968 1969- FPGA Support: CONFIG_FPGA 1970 1971 Enables FPGA subsystem. 1972 1973 CONFIG_FPGA_<vendor> 1974 1975 Enables support for specific chip vendors. 1976 (ALTERA, XILINX) 1977 1978 CONFIG_FPGA_<family> 1979 1980 Enables support for FPGA family. 1981 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1982 1983 CONFIG_FPGA_COUNT 1984 1985 Specify the number of FPGA devices to support. 1986 1987 CONFIG_SYS_FPGA_PROG_FEEDBACK 1988 1989 Enable printing of hash marks during FPGA configuration. 1990 1991 CONFIG_SYS_FPGA_CHECK_BUSY 1992 1993 Enable checks on FPGA configuration interface busy 1994 status by the configuration function. This option 1995 will require a board or device specific function to 1996 be written. 1997 1998 CONFIG_FPGA_DELAY 1999 2000 If defined, a function that provides delays in the FPGA 2001 configuration driver. 2002 2003 CONFIG_SYS_FPGA_CHECK_CTRLC 2004 Allow Control-C to interrupt FPGA configuration 2005 2006 CONFIG_SYS_FPGA_CHECK_ERROR 2007 2008 Check for configuration errors during FPGA bitfile 2009 loading. For example, abort during Virtex II 2010 configuration if the INIT_B line goes low (which 2011 indicated a CRC error). 2012 2013 CONFIG_SYS_FPGA_WAIT_INIT 2014 2015 Maximum time to wait for the INIT_B line to de-assert 2016 after PROB_B has been de-asserted during a Virtex II 2017 FPGA configuration sequence. The default time is 500 2018 ms. 2019 2020 CONFIG_SYS_FPGA_WAIT_BUSY 2021 2022 Maximum time to wait for BUSY to de-assert during 2023 Virtex II FPGA configuration. The default is 5 ms. 2024 2025 CONFIG_SYS_FPGA_WAIT_CONFIG 2026 2027 Time to wait after FPGA configuration. The default is 2028 200 ms. 2029 2030- Configuration Management: 2031 CONFIG_BUILD_TARGET 2032 2033 Some SoCs need special image types (e.g. U-Boot binary 2034 with a special header) as build targets. By defining 2035 CONFIG_BUILD_TARGET in the SoC / board header, this 2036 special image will be automatically built upon calling 2037 make / buildman. 2038 2039 CONFIG_IDENT_STRING 2040 2041 If defined, this string will be added to the U-Boot 2042 version information (U_BOOT_VERSION) 2043 2044- Vendor Parameter Protection: 2045 2046 U-Boot considers the values of the environment 2047 variables "serial#" (Board Serial Number) and 2048 "ethaddr" (Ethernet Address) to be parameters that 2049 are set once by the board vendor / manufacturer, and 2050 protects these variables from casual modification by 2051 the user. Once set, these variables are read-only, 2052 and write or delete attempts are rejected. You can 2053 change this behaviour: 2054 2055 If CONFIG_ENV_OVERWRITE is #defined in your config 2056 file, the write protection for vendor parameters is 2057 completely disabled. Anybody can change or delete 2058 these parameters. 2059 2060 Alternatively, if you define _both_ an ethaddr in the 2061 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 2062 Ethernet address is installed in the environment, 2063 which can be changed exactly ONCE by the user. [The 2064 serial# is unaffected by this, i. e. it remains 2065 read-only.] 2066 2067 The same can be accomplished in a more flexible way 2068 for any variable by configuring the type of access 2069 to allow for those variables in the ".flags" variable 2070 or define CONFIG_ENV_FLAGS_LIST_STATIC. 2071 2072- Protected RAM: 2073 CONFIG_PRAM 2074 2075 Define this variable to enable the reservation of 2076 "protected RAM", i. e. RAM which is not overwritten 2077 by U-Boot. Define CONFIG_PRAM to hold the number of 2078 kB you want to reserve for pRAM. You can overwrite 2079 this default value by defining an environment 2080 variable "pram" to the number of kB you want to 2081 reserve. Note that the board info structure will 2082 still show the full amount of RAM. If pRAM is 2083 reserved, a new environment variable "mem" will 2084 automatically be defined to hold the amount of 2085 remaining RAM in a form that can be passed as boot 2086 argument to Linux, for instance like that: 2087 2088 setenv bootargs ... mem=\${mem} 2089 saveenv 2090 2091 This way you can tell Linux not to use this memory, 2092 either, which results in a memory region that will 2093 not be affected by reboots. 2094 2095 *WARNING* If your board configuration uses automatic 2096 detection of the RAM size, you must make sure that 2097 this memory test is non-destructive. So far, the 2098 following board configurations are known to be 2099 "pRAM-clean": 2100 2101 IVMS8, IVML24, SPD8xx, 2102 HERMES, IP860, RPXlite, LWMON, 2103 FLAGADM 2104 2105- Access to physical memory region (> 4GB) 2106 Some basic support is provided for operations on memory not 2107 normally accessible to U-Boot - e.g. some architectures 2108 support access to more than 4GB of memory on 32-bit 2109 machines using physical address extension or similar. 2110 Define CONFIG_PHYSMEM to access this basic support, which 2111 currently only supports clearing the memory. 2112 2113- Error Recovery: 2114 CONFIG_NET_RETRY_COUNT 2115 2116 This variable defines the number of retries for 2117 network operations like ARP, RARP, TFTP, or BOOTP 2118 before giving up the operation. If not defined, a 2119 default value of 5 is used. 2120 2121 CONFIG_ARP_TIMEOUT 2122 2123 Timeout waiting for an ARP reply in milliseconds. 2124 2125 CONFIG_NFS_TIMEOUT 2126 2127 Timeout in milliseconds used in NFS protocol. 2128 If you encounter "ERROR: Cannot umount" in nfs command, 2129 try longer timeout such as 2130 #define CONFIG_NFS_TIMEOUT 10000UL 2131 2132- Command Interpreter: 2133 CONFIG_SYS_PROMPT_HUSH_PS2 2134 2135 This defines the secondary prompt string, which is 2136 printed when the command interpreter needs more input 2137 to complete a command. Usually "> ". 2138 2139 Note: 2140 2141 In the current implementation, the local variables 2142 space and global environment variables space are 2143 separated. Local variables are those you define by 2144 simply typing `name=value'. To access a local 2145 variable later on, you have write `$name' or 2146 `${name}'; to execute the contents of a variable 2147 directly type `$name' at the command prompt. 2148 2149 Global environment variables are those you use 2150 setenv/printenv to work with. To run a command stored 2151 in such a variable, you need to use the run command, 2152 and you must not use the '$' sign to access them. 2153 2154 To store commands and special characters in a 2155 variable, please use double quotation marks 2156 surrounding the whole text of the variable, instead 2157 of the backslashes before semicolons and special 2158 symbols. 2159 2160- Command Line Editing and History: 2161 CONFIG_CMDLINE_PS_SUPPORT 2162 2163 Enable support for changing the command prompt string 2164 at run-time. Only static string is supported so far. 2165 The string is obtained from environment variables PS1 2166 and PS2. 2167 2168- Default Environment: 2169 CONFIG_EXTRA_ENV_SETTINGS 2170 2171 Define this to contain any number of null terminated 2172 strings (variable = value pairs) that will be part of 2173 the default environment compiled into the boot image. 2174 2175 For example, place something like this in your 2176 board's config file: 2177 2178 #define CONFIG_EXTRA_ENV_SETTINGS \ 2179 "myvar1=value1\0" \ 2180 "myvar2=value2\0" 2181 2182 Warning: This method is based on knowledge about the 2183 internal format how the environment is stored by the 2184 U-Boot code. This is NOT an official, exported 2185 interface! Although it is unlikely that this format 2186 will change soon, there is no guarantee either. 2187 You better know what you are doing here. 2188 2189 Note: overly (ab)use of the default environment is 2190 discouraged. Make sure to check other ways to preset 2191 the environment like the "source" command or the 2192 boot command first. 2193 2194 CONFIG_DELAY_ENVIRONMENT 2195 2196 Normally the environment is loaded when the board is 2197 initialised so that it is available to U-Boot. This inhibits 2198 that so that the environment is not available until 2199 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 2200 this is instead controlled by the value of 2201 /config/load-environment. 2202 2203- Serial Flash support 2204 Usage requires an initial 'sf probe' to define the serial 2205 flash parameters, followed by read/write/erase/update 2206 commands. 2207 2208 The following defaults may be provided by the platform 2209 to handle the common case when only a single serial 2210 flash is present on the system. 2211 2212 CONFIG_SF_DEFAULT_BUS Bus identifier 2213 CONFIG_SF_DEFAULT_CS Chip-select 2214 CONFIG_SF_DEFAULT_MODE (see include/spi.h) 2215 CONFIG_SF_DEFAULT_SPEED in Hz 2216 2217 2218- TFTP Fixed UDP Port: 2219 CONFIG_TFTP_PORT 2220 2221 If this is defined, the environment variable tftpsrcp 2222 is used to supply the TFTP UDP source port value. 2223 If tftpsrcp isn't defined, the normal pseudo-random port 2224 number generator is used. 2225 2226 Also, the environment variable tftpdstp is used to supply 2227 the TFTP UDP destination port value. If tftpdstp isn't 2228 defined, the normal port 69 is used. 2229 2230 The purpose for tftpsrcp is to allow a TFTP server to 2231 blindly start the TFTP transfer using the pre-configured 2232 target IP address and UDP port. This has the effect of 2233 "punching through" the (Windows XP) firewall, allowing 2234 the remainder of the TFTP transfer to proceed normally. 2235 A better solution is to properly configure the firewall, 2236 but sometimes that is not allowed. 2237 2238- Show boot progress: 2239 CONFIG_SHOW_BOOT_PROGRESS 2240 2241 Defining this option allows to add some board- 2242 specific code (calling a user-provided function 2243 "show_boot_progress(int)") that enables you to show 2244 the system's boot progress on some display (for 2245 example, some LED's) on your board. At the moment, 2246 the following checkpoints are implemented: 2247 2248 2249Legacy uImage format: 2250 2251 Arg Where When 2252 1 common/cmd_bootm.c before attempting to boot an image 2253 -1 common/cmd_bootm.c Image header has bad magic number 2254 2 common/cmd_bootm.c Image header has correct magic number 2255 -2 common/cmd_bootm.c Image header has bad checksum 2256 3 common/cmd_bootm.c Image header has correct checksum 2257 -3 common/cmd_bootm.c Image data has bad checksum 2258 4 common/cmd_bootm.c Image data has correct checksum 2259 -4 common/cmd_bootm.c Image is for unsupported architecture 2260 5 common/cmd_bootm.c Architecture check OK 2261 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi) 2262 6 common/cmd_bootm.c Image Type check OK 2263 -6 common/cmd_bootm.c gunzip uncompression error 2264 -7 common/cmd_bootm.c Unimplemented compression type 2265 7 common/cmd_bootm.c Uncompression OK 2266 8 common/cmd_bootm.c No uncompress/copy overwrite error 2267 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 2268 2269 9 common/image.c Start initial ramdisk verification 2270 -10 common/image.c Ramdisk header has bad magic number 2271 -11 common/image.c Ramdisk header has bad checksum 2272 10 common/image.c Ramdisk header is OK 2273 -12 common/image.c Ramdisk data has bad checksum 2274 11 common/image.c Ramdisk data has correct checksum 2275 12 common/image.c Ramdisk verification complete, start loading 2276 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk) 2277 13 common/image.c Start multifile image verification 2278 14 common/image.c No initial ramdisk, no multifile, continue. 2279 2280 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS 2281 2282 -30 arch/powerpc/lib/board.c Fatal error, hang the system 2283 -31 post/post.c POST test failed, detected by post_output_backlog() 2284 -32 post/post.c POST test failed, detected by post_run_single() 2285 2286 34 common/cmd_doc.c before loading a Image from a DOC device 2287 -35 common/cmd_doc.c Bad usage of "doc" command 2288 35 common/cmd_doc.c correct usage of "doc" command 2289 -36 common/cmd_doc.c No boot device 2290 36 common/cmd_doc.c correct boot device 2291 -37 common/cmd_doc.c Unknown Chip ID on boot device 2292 37 common/cmd_doc.c correct chip ID found, device available 2293 -38 common/cmd_doc.c Read Error on boot device 2294 38 common/cmd_doc.c reading Image header from DOC device OK 2295 -39 common/cmd_doc.c Image header has bad magic number 2296 39 common/cmd_doc.c Image header has correct magic number 2297 -40 common/cmd_doc.c Error reading Image from DOC device 2298 40 common/cmd_doc.c Image header has correct magic number 2299 41 common/cmd_ide.c before loading a Image from a IDE device 2300 -42 common/cmd_ide.c Bad usage of "ide" command 2301 42 common/cmd_ide.c correct usage of "ide" command 2302 -43 common/cmd_ide.c No boot device 2303 43 common/cmd_ide.c boot device found 2304 -44 common/cmd_ide.c Device not available 2305 44 common/cmd_ide.c Device available 2306 -45 common/cmd_ide.c wrong partition selected 2307 45 common/cmd_ide.c partition selected 2308 -46 common/cmd_ide.c Unknown partition table 2309 46 common/cmd_ide.c valid partition table found 2310 -47 common/cmd_ide.c Invalid partition type 2311 47 common/cmd_ide.c correct partition type 2312 -48 common/cmd_ide.c Error reading Image Header on boot device 2313 48 common/cmd_ide.c reading Image Header from IDE device OK 2314 -49 common/cmd_ide.c Image header has bad magic number 2315 49 common/cmd_ide.c Image header has correct magic number 2316 -50 common/cmd_ide.c Image header has bad checksum 2317 50 common/cmd_ide.c Image header has correct checksum 2318 -51 common/cmd_ide.c Error reading Image from IDE device 2319 51 common/cmd_ide.c reading Image from IDE device OK 2320 52 common/cmd_nand.c before loading a Image from a NAND device 2321 -53 common/cmd_nand.c Bad usage of "nand" command 2322 53 common/cmd_nand.c correct usage of "nand" command 2323 -54 common/cmd_nand.c No boot device 2324 54 common/cmd_nand.c boot device found 2325 -55 common/cmd_nand.c Unknown Chip ID on boot device 2326 55 common/cmd_nand.c correct chip ID found, device available 2327 -56 common/cmd_nand.c Error reading Image Header on boot device 2328 56 common/cmd_nand.c reading Image Header from NAND device OK 2329 -57 common/cmd_nand.c Image header has bad magic number 2330 57 common/cmd_nand.c Image header has correct magic number 2331 -58 common/cmd_nand.c Error reading Image from NAND device 2332 58 common/cmd_nand.c reading Image from NAND device OK 2333 2334 -60 common/env_common.c Environment has a bad CRC, using default 2335 2336 64 net/eth.c starting with Ethernet configuration. 2337 -64 net/eth.c no Ethernet found. 2338 65 net/eth.c Ethernet found. 2339 2340 -80 common/cmd_net.c usage wrong 2341 80 common/cmd_net.c before calling net_loop() 2342 -81 common/cmd_net.c some error in net_loop() occurred 2343 81 common/cmd_net.c net_loop() back without error 2344 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 2345 82 common/cmd_net.c trying automatic boot 2346 83 common/cmd_net.c running "source" command 2347 -83 common/cmd_net.c some error in automatic boot or "source" command 2348 84 common/cmd_net.c end without errors 2349 2350FIT uImage format: 2351 2352 Arg Where When 2353 100 common/cmd_bootm.c Kernel FIT Image has correct format 2354 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format 2355 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration 2356 -101 common/cmd_bootm.c Can't get configuration for kernel subimage 2357 102 common/cmd_bootm.c Kernel unit name specified 2358 -103 common/cmd_bootm.c Can't get kernel subimage node offset 2359 103 common/cmd_bootm.c Found configuration node 2360 104 common/cmd_bootm.c Got kernel subimage node offset 2361 -104 common/cmd_bootm.c Kernel subimage hash verification failed 2362 105 common/cmd_bootm.c Kernel subimage hash verification OK 2363 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture 2364 106 common/cmd_bootm.c Architecture check OK 2365 -106 common/cmd_bootm.c Kernel subimage has wrong type 2366 107 common/cmd_bootm.c Kernel subimage type OK 2367 -107 common/cmd_bootm.c Can't get kernel subimage data/size 2368 108 common/cmd_bootm.c Got kernel subimage data/size 2369 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT) 2370 -109 common/cmd_bootm.c Can't get kernel subimage type 2371 -110 common/cmd_bootm.c Can't get kernel subimage comp 2372 -111 common/cmd_bootm.c Can't get kernel subimage os 2373 -112 common/cmd_bootm.c Can't get kernel subimage load address 2374 -113 common/cmd_bootm.c Image uncompress/copy overwrite error 2375 2376 120 common/image.c Start initial ramdisk verification 2377 -120 common/image.c Ramdisk FIT image has incorrect format 2378 121 common/image.c Ramdisk FIT image has correct format 2379 122 common/image.c No ramdisk subimage unit name, using configuration 2380 -122 common/image.c Can't get configuration for ramdisk subimage 2381 123 common/image.c Ramdisk unit name specified 2382 -124 common/image.c Can't get ramdisk subimage node offset 2383 125 common/image.c Got ramdisk subimage node offset 2384 -125 common/image.c Ramdisk subimage hash verification failed 2385 126 common/image.c Ramdisk subimage hash verification OK 2386 -126 common/image.c Ramdisk subimage for unsupported architecture 2387 127 common/image.c Architecture check OK 2388 -127 common/image.c Can't get ramdisk subimage data/size 2389 128 common/image.c Got ramdisk subimage data/size 2390 129 common/image.c Can't get ramdisk load address 2391 -129 common/image.c Got ramdisk load address 2392 2393 -130 common/cmd_doc.c Incorrect FIT image format 2394 131 common/cmd_doc.c FIT image format OK 2395 2396 -140 common/cmd_ide.c Incorrect FIT image format 2397 141 common/cmd_ide.c FIT image format OK 2398 2399 -150 common/cmd_nand.c Incorrect FIT image format 2400 151 common/cmd_nand.c FIT image format OK 2401 2402- Standalone program support: 2403 CONFIG_STANDALONE_LOAD_ADDR 2404 2405 This option defines a board specific value for the 2406 address where standalone program gets loaded, thus 2407 overwriting the architecture dependent default 2408 settings. 2409 2410- Frame Buffer Address: 2411 CONFIG_FB_ADDR 2412 2413 Define CONFIG_FB_ADDR if you want to use specific 2414 address for frame buffer. This is typically the case 2415 when using a graphics controller has separate video 2416 memory. U-Boot will then place the frame buffer at 2417 the given address instead of dynamically reserving it 2418 in system RAM by calling lcd_setmem(), which grabs 2419 the memory for the frame buffer depending on the 2420 configured panel size. 2421 2422 Please see board_init_f function. 2423 2424- Automatic software updates via TFTP server 2425 CONFIG_UPDATE_TFTP 2426 CONFIG_UPDATE_TFTP_CNT_MAX 2427 CONFIG_UPDATE_TFTP_MSEC_MAX 2428 2429 These options enable and control the auto-update feature; 2430 for a more detailed description refer to doc/README.update. 2431 2432- MTD Support (mtdparts command, UBI support) 2433 CONFIG_MTD_UBI_WL_THRESHOLD 2434 This parameter defines the maximum difference between the highest 2435 erase counter value and the lowest erase counter value of eraseblocks 2436 of UBI devices. When this threshold is exceeded, UBI starts performing 2437 wear leveling by means of moving data from eraseblock with low erase 2438 counter to eraseblocks with high erase counter. 2439 2440 The default value should be OK for SLC NAND flashes, NOR flashes and 2441 other flashes which have eraseblock life-cycle 100000 or more. 2442 However, in case of MLC NAND flashes which typically have eraseblock 2443 life-cycle less than 10000, the threshold should be lessened (e.g., 2444 to 128 or 256, although it does not have to be power of 2). 2445 2446 default: 4096 2447 2448 CONFIG_MTD_UBI_BEB_LIMIT 2449 This option specifies the maximum bad physical eraseblocks UBI 2450 expects on the MTD device (per 1024 eraseblocks). If the 2451 underlying flash does not admit of bad eraseblocks (e.g. NOR 2452 flash), this value is ignored. 2453 2454 NAND datasheets often specify the minimum and maximum NVM 2455 (Number of Valid Blocks) for the flashes' endurance lifetime. 2456 The maximum expected bad eraseblocks per 1024 eraseblocks 2457 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2458 which gives 20 for most NANDs (MaxNVB is basically the total 2459 count of eraseblocks on the chip). 2460 2461 To put it differently, if this value is 20, UBI will try to 2462 reserve about 1.9% of physical eraseblocks for bad blocks 2463 handling. And that will be 1.9% of eraseblocks on the entire 2464 NAND chip, not just the MTD partition UBI attaches. This means 2465 that if you have, say, a NAND flash chip admits maximum 40 bad 2466 eraseblocks, and it is split on two MTD partitions of the same 2467 size, UBI will reserve 40 eraseblocks when attaching a 2468 partition. 2469 2470 default: 20 2471 2472 CONFIG_MTD_UBI_FASTMAP 2473 Fastmap is a mechanism which allows attaching an UBI device 2474 in nearly constant time. Instead of scanning the whole MTD device it 2475 only has to locate a checkpoint (called fastmap) on the device. 2476 The on-flash fastmap contains all information needed to attach 2477 the device. Using fastmap makes only sense on large devices where 2478 attaching by scanning takes long. UBI will not automatically install 2479 a fastmap on old images, but you can set the UBI parameter 2480 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2481 that fastmap-enabled images are still usable with UBI implementations 2482 without fastmap support. On typical flash devices the whole fastmap 2483 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2484 2485 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2486 Set this parameter to enable fastmap automatically on images 2487 without a fastmap. 2488 default: 0 2489 2490 CONFIG_MTD_UBI_FM_DEBUG 2491 Enable UBI fastmap debug 2492 default: 0 2493 2494- SPL framework 2495 CONFIG_SPL 2496 Enable building of SPL globally. 2497 2498 CONFIG_SPL_LDSCRIPT 2499 LDSCRIPT for linking the SPL binary. 2500 2501 CONFIG_SPL_MAX_FOOTPRINT 2502 Maximum size in memory allocated to the SPL, BSS included. 2503 When defined, the linker checks that the actual memory 2504 used by SPL from _start to __bss_end does not exceed it. 2505 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2506 must not be both defined at the same time. 2507 2508 CONFIG_SPL_MAX_SIZE 2509 Maximum size of the SPL image (text, data, rodata, and 2510 linker lists sections), BSS excluded. 2511 When defined, the linker checks that the actual size does 2512 not exceed it. 2513 2514 CONFIG_SPL_TEXT_BASE 2515 TEXT_BASE for linking the SPL binary. 2516 2517 CONFIG_SPL_RELOC_TEXT_BASE 2518 Address to relocate to. If unspecified, this is equal to 2519 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2520 2521 CONFIG_SPL_BSS_START_ADDR 2522 Link address for the BSS within the SPL binary. 2523 2524 CONFIG_SPL_BSS_MAX_SIZE 2525 Maximum size in memory allocated to the SPL BSS. 2526 When defined, the linker checks that the actual memory used 2527 by SPL from __bss_start to __bss_end does not exceed it. 2528 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2529 must not be both defined at the same time. 2530 2531 CONFIG_SPL_STACK 2532 Adress of the start of the stack SPL will use 2533 2534 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2535 When defined, SPL will panic() if the image it has 2536 loaded does not have a signature. 2537 Defining this is useful when code which loads images 2538 in SPL cannot guarantee that absolutely all read errors 2539 will be caught. 2540 An example is the LPC32XX MLC NAND driver, which will 2541 consider that a completely unreadable NAND block is bad, 2542 and thus should be skipped silently. 2543 2544 CONFIG_SPL_RELOC_STACK 2545 Adress of the start of the stack SPL will use after 2546 relocation. If unspecified, this is equal to 2547 CONFIG_SPL_STACK. 2548 2549 CONFIG_SYS_SPL_MALLOC_START 2550 Starting address of the malloc pool used in SPL. 2551 When this option is set the full malloc is used in SPL and 2552 it is set up by spl_init() and before that, the simple malloc() 2553 can be used if CONFIG_SYS_MALLOC_F is defined. 2554 2555 CONFIG_SYS_SPL_MALLOC_SIZE 2556 The size of the malloc pool used in SPL. 2557 2558 CONFIG_SPL_OS_BOOT 2559 Enable booting directly to an OS from SPL. 2560 See also: doc/README.falcon 2561 2562 CONFIG_SPL_DISPLAY_PRINT 2563 For ARM, enable an optional function to print more information 2564 about the running system. 2565 2566 CONFIG_SPL_INIT_MINIMAL 2567 Arch init code should be built for a very small image 2568 2569 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2570 Partition on the MMC to load U-Boot from when the MMC is being 2571 used in raw mode 2572 2573 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2574 Sector to load kernel uImage from when MMC is being 2575 used in raw mode (for Falcon mode) 2576 2577 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2578 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2579 Sector and number of sectors to load kernel argument 2580 parameters from when MMC is being used in raw mode 2581 (for falcon mode) 2582 2583 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 2584 Partition on the MMC to load U-Boot from when the MMC is being 2585 used in fs mode 2586 2587 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2588 Filename to read to load U-Boot when reading from filesystem 2589 2590 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2591 Filename to read to load kernel uImage when reading 2592 from filesystem (for Falcon mode) 2593 2594 CONFIG_SPL_FS_LOAD_ARGS_NAME 2595 Filename to read to load kernel argument parameters 2596 when reading from filesystem (for Falcon mode) 2597 2598 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2599 Set this for NAND SPL on PPC mpc83xx targets, so that 2600 start.S waits for the rest of the SPL to load before 2601 continuing (the hardware starts execution after just 2602 loading the first page rather than the full 4K). 2603 2604 CONFIG_SPL_SKIP_RELOCATE 2605 Avoid SPL relocation 2606 2607 CONFIG_SPL_NAND_BASE 2608 Include nand_base.c in the SPL. Requires 2609 CONFIG_SPL_NAND_DRIVERS. 2610 2611 CONFIG_SPL_NAND_DRIVERS 2612 SPL uses normal NAND drivers, not minimal drivers. 2613 2614 CONFIG_SPL_NAND_IDENT 2615 SPL uses the chip ID list to identify the NAND flash. 2616 Requires CONFIG_SPL_NAND_BASE. 2617 2618 CONFIG_SPL_NAND_ECC 2619 Include standard software ECC in the SPL 2620 2621 CONFIG_SPL_NAND_SIMPLE 2622 Support for NAND boot using simple NAND drivers that 2623 expose the cmd_ctrl() interface. 2624 2625 CONFIG_SPL_UBI 2626 Support for a lightweight UBI (fastmap) scanner and 2627 loader 2628 2629 CONFIG_SPL_NAND_RAW_ONLY 2630 Support to boot only raw u-boot.bin images. Use this only 2631 if you need to save space. 2632 2633 CONFIG_SPL_COMMON_INIT_DDR 2634 Set for common ddr init with serial presence detect in 2635 SPL binary. 2636 2637 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2638 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2639 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2640 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2641 CONFIG_SYS_NAND_ECCBYTES 2642 Defines the size and behavior of the NAND that SPL uses 2643 to read U-Boot 2644 2645 CONFIG_SPL_NAND_BOOT 2646 Add support NAND boot 2647 2648 CONFIG_SYS_NAND_U_BOOT_OFFS 2649 Location in NAND to read U-Boot from 2650 2651 CONFIG_SYS_NAND_U_BOOT_DST 2652 Location in memory to load U-Boot to 2653 2654 CONFIG_SYS_NAND_U_BOOT_SIZE 2655 Size of image to load 2656 2657 CONFIG_SYS_NAND_U_BOOT_START 2658 Entry point in loaded image to jump to 2659 2660 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2661 Define this if you need to first read the OOB and then the 2662 data. This is used, for example, on davinci platforms. 2663 2664 CONFIG_SPL_RAM_DEVICE 2665 Support for running image already present in ram, in SPL binary 2666 2667 CONFIG_SPL_PAD_TO 2668 Image offset to which the SPL should be padded before appending 2669 the SPL payload. By default, this is defined as 2670 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2671 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2672 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2673 2674 CONFIG_SPL_TARGET 2675 Final target image containing SPL and payload. Some SPLs 2676 use an arch-specific makefile fragment instead, for 2677 example if more than one image needs to be produced. 2678 2679 CONFIG_SPL_FIT_PRINT 2680 Printing information about a FIT image adds quite a bit of 2681 code to SPL. So this is normally disabled in SPL. Use this 2682 option to re-enable it. This will affect the output of the 2683 bootm command when booting a FIT image. 2684 2685- TPL framework 2686 CONFIG_TPL 2687 Enable building of TPL globally. 2688 2689 CONFIG_TPL_PAD_TO 2690 Image offset to which the TPL should be padded before appending 2691 the TPL payload. By default, this is defined as 2692 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2693 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2694 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2695 2696- Interrupt support (PPC): 2697 2698 There are common interrupt_init() and timer_interrupt() 2699 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2700 for CPU specific initialization. interrupt_init_cpu() 2701 should set decrementer_count to appropriate value. If 2702 CPU resets decrementer automatically after interrupt 2703 (ppc4xx) it should set decrementer_count to zero. 2704 timer_interrupt() calls timer_interrupt_cpu() for CPU 2705 specific handling. If board has watchdog / status_led 2706 / other_activity_monitor it works automatically from 2707 general timer_interrupt(). 2708 2709 2710Board initialization settings: 2711------------------------------ 2712 2713During Initialization u-boot calls a number of board specific functions 2714to allow the preparation of board specific prerequisites, e.g. pin setup 2715before drivers are initialized. To enable these callbacks the 2716following configuration macros have to be defined. Currently this is 2717architecture specific, so please check arch/your_architecture/lib/board.c 2718typically in board_init_f() and board_init_r(). 2719 2720- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2721- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2722- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2723- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2724 2725Configuration Settings: 2726----------------------- 2727 2728- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2729 Optionally it can be defined to support 64-bit memory commands. 2730 2731- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2732 undefine this when you're short of memory. 2733 2734- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2735 width of the commands listed in the 'help' command output. 2736 2737- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2738 prompt for user input. 2739 2740- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2741 2742- CONFIG_SYS_PBSIZE: Buffer size for Console output 2743 2744- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2745 2746- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2747 the application (usually a Linux kernel) when it is 2748 booted 2749 2750- CONFIG_SYS_BAUDRATE_TABLE: 2751 List of legal baudrate settings for this board. 2752 2753- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: 2754 Begin and End addresses of the area used by the 2755 simple memory test. 2756 2757- CONFIG_SYS_MEMTEST_SCRATCH: 2758 Scratch address used by the alternate memory test 2759 You only need to set this if address zero isn't writeable 2760 2761- CONFIG_SYS_MEM_RESERVE_SECURE 2762 Only implemented for ARMv8 for now. 2763 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2764 is substracted from total RAM and won't be reported to OS. 2765 This memory can be used as secure memory. A variable 2766 gd->arch.secure_ram is used to track the location. In systems 2767 the RAM base is not zero, or RAM is divided into banks, 2768 this variable needs to be recalcuated to get the address. 2769 2770- CONFIG_SYS_MEM_TOP_HIDE: 2771 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2772 this specified memory area will get subtracted from the top 2773 (end) of RAM and won't get "touched" at all by U-Boot. By 2774 fixing up gd->ram_size the Linux kernel should gets passed 2775 the now "corrected" memory size and won't touch it either. 2776 This should work for arch/ppc and arch/powerpc. Only Linux 2777 board ports in arch/powerpc with bootwrapper support that 2778 recalculate the memory size from the SDRAM controller setup 2779 will have to get fixed in Linux additionally. 2780 2781 This option can be used as a workaround for the 440EPx/GRx 2782 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2783 be touched. 2784 2785 WARNING: Please make sure that this value is a multiple of 2786 the Linux page size (normally 4k). If this is not the case, 2787 then the end address of the Linux memory will be located at a 2788 non page size aligned address and this could cause major 2789 problems. 2790 2791- CONFIG_SYS_LOADS_BAUD_CHANGE: 2792 Enable temporary baudrate change while serial download 2793 2794- CONFIG_SYS_SDRAM_BASE: 2795 Physical start address of SDRAM. _Must_ be 0 here. 2796 2797- CONFIG_SYS_FLASH_BASE: 2798 Physical start address of Flash memory. 2799 2800- CONFIG_SYS_MONITOR_BASE: 2801 Physical start address of boot monitor code (set by 2802 make config files to be same as the text base address 2803 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2804 CONFIG_SYS_FLASH_BASE when booting from flash. 2805 2806- CONFIG_SYS_MONITOR_LEN: 2807 Size of memory reserved for monitor code, used to 2808 determine _at_compile_time_ (!) if the environment is 2809 embedded within the U-Boot image, or in a separate 2810 flash sector. 2811 2812- CONFIG_SYS_MALLOC_LEN: 2813 Size of DRAM reserved for malloc() use. 2814 2815- CONFIG_SYS_MALLOC_F_LEN 2816 Size of the malloc() pool for use before relocation. If 2817 this is defined, then a very simple malloc() implementation 2818 will become available before relocation. The address is just 2819 below the global data, and the stack is moved down to make 2820 space. 2821 2822 This feature allocates regions with increasing addresses 2823 within the region. calloc() is supported, but realloc() 2824 is not available. free() is supported but does nothing. 2825 The memory will be freed (or in fact just forgotten) when 2826 U-Boot relocates itself. 2827 2828- CONFIG_SYS_MALLOC_SIMPLE 2829 Provides a simple and small malloc() and calloc() for those 2830 boards which do not use the full malloc in SPL (which is 2831 enabled with CONFIG_SYS_SPL_MALLOC_START). 2832 2833- CONFIG_SYS_NONCACHED_MEMORY: 2834 Size of non-cached memory area. This area of memory will be 2835 typically located right below the malloc() area and mapped 2836 uncached in the MMU. This is useful for drivers that would 2837 otherwise require a lot of explicit cache maintenance. For 2838 some drivers it's also impossible to properly maintain the 2839 cache. For example if the regions that need to be flushed 2840 are not a multiple of the cache-line size, *and* padding 2841 cannot be allocated between the regions to align them (i.e. 2842 if the HW requires a contiguous array of regions, and the 2843 size of each region is not cache-aligned), then a flush of 2844 one region may result in overwriting data that hardware has 2845 written to another region in the same cache-line. This can 2846 happen for example in network drivers where descriptors for 2847 buffers are typically smaller than the CPU cache-line (e.g. 2848 16 bytes vs. 32 or 64 bytes). 2849 2850 Non-cached memory is only supported on 32-bit ARM at present. 2851 2852- CONFIG_SYS_BOOTM_LEN: 2853 Normally compressed uImages are limited to an 2854 uncompressed size of 8 MBytes. If this is not enough, 2855 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2856 to adjust this setting to your needs. 2857 2858- CONFIG_SYS_BOOTMAPSZ: 2859 Maximum size of memory mapped by the startup code of 2860 the Linux kernel; all data that must be processed by 2861 the Linux kernel (bd_info, boot arguments, FDT blob if 2862 used) must be put below this limit, unless "bootm_low" 2863 environment variable is defined and non-zero. In such case 2864 all data for the Linux kernel must be between "bootm_low" 2865 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2866 variable "bootm_mapsize" will override the value of 2867 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2868 then the value in "bootm_size" will be used instead. 2869 2870- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2871 Enable initrd_high functionality. If defined then the 2872 initrd_high feature is enabled and the bootm ramdisk subcommand 2873 is enabled. 2874 2875- CONFIG_SYS_BOOT_GET_CMDLINE: 2876 Enables allocating and saving kernel cmdline in space between 2877 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2878 2879- CONFIG_SYS_BOOT_GET_KBD: 2880 Enables allocating and saving a kernel copy of the bd_info in 2881 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2882 2883- CONFIG_SYS_MAX_FLASH_BANKS: 2884 Max number of Flash memory banks 2885 2886- CONFIG_SYS_MAX_FLASH_SECT: 2887 Max number of sectors on a Flash chip 2888 2889- CONFIG_SYS_FLASH_ERASE_TOUT: 2890 Timeout for Flash erase operations (in ms) 2891 2892- CONFIG_SYS_FLASH_WRITE_TOUT: 2893 Timeout for Flash write operations (in ms) 2894 2895- CONFIG_SYS_FLASH_LOCK_TOUT 2896 Timeout for Flash set sector lock bit operation (in ms) 2897 2898- CONFIG_SYS_FLASH_UNLOCK_TOUT 2899 Timeout for Flash clear lock bits operation (in ms) 2900 2901- CONFIG_SYS_FLASH_PROTECTION 2902 If defined, hardware flash sectors protection is used 2903 instead of U-Boot software protection. 2904 2905- CONFIG_SYS_DIRECT_FLASH_TFTP: 2906 2907 Enable TFTP transfers directly to flash memory; 2908 without this option such a download has to be 2909 performed in two steps: (1) download to RAM, and (2) 2910 copy from RAM to flash. 2911 2912 The two-step approach is usually more reliable, since 2913 you can check if the download worked before you erase 2914 the flash, but in some situations (when system RAM is 2915 too limited to allow for a temporary copy of the 2916 downloaded image) this option may be very useful. 2917 2918- CONFIG_SYS_FLASH_CFI: 2919 Define if the flash driver uses extra elements in the 2920 common flash structure for storing flash geometry. 2921 2922- CONFIG_FLASH_CFI_DRIVER 2923 This option also enables the building of the cfi_flash driver 2924 in the drivers directory 2925 2926- CONFIG_FLASH_CFI_MTD 2927 This option enables the building of the cfi_mtd driver 2928 in the drivers directory. The driver exports CFI flash 2929 to the MTD layer. 2930 2931- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2932 Use buffered writes to flash. 2933 2934- CONFIG_FLASH_SPANSION_S29WS_N 2935 s29ws-n MirrorBit flash has non-standard addresses for buffered 2936 write commands. 2937 2938- CONFIG_SYS_FLASH_QUIET_TEST 2939 If this option is defined, the common CFI flash doesn't 2940 print it's warning upon not recognized FLASH banks. This 2941 is useful, if some of the configured banks are only 2942 optionally available. 2943 2944- CONFIG_FLASH_SHOW_PROGRESS 2945 If defined (must be an integer), print out countdown 2946 digits and dots. Recommended value: 45 (9..1) for 80 2947 column displays, 15 (3..1) for 40 column displays. 2948 2949- CONFIG_FLASH_VERIFY 2950 If defined, the content of the flash (destination) is compared 2951 against the source after the write operation. An error message 2952 will be printed when the contents are not identical. 2953 Please note that this option is useless in nearly all cases, 2954 since such flash programming errors usually are detected earlier 2955 while unprotecting/erasing/programming. Please only enable 2956 this option if you really know what you are doing. 2957 2958- CONFIG_SYS_RX_ETH_BUFFER: 2959 Defines the number of Ethernet receive buffers. On some 2960 Ethernet controllers it is recommended to set this value 2961 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2962 buffers can be full shortly after enabling the interface 2963 on high Ethernet traffic. 2964 Defaults to 4 if not defined. 2965 2966- CONFIG_ENV_MAX_ENTRIES 2967 2968 Maximum number of entries in the hash table that is used 2969 internally to store the environment settings. The default 2970 setting is supposed to be generous and should work in most 2971 cases. This setting can be used to tune behaviour; see 2972 lib/hashtable.c for details. 2973 2974- CONFIG_ENV_FLAGS_LIST_DEFAULT 2975- CONFIG_ENV_FLAGS_LIST_STATIC 2976 Enable validation of the values given to environment variables when 2977 calling env set. Variables can be restricted to only decimal, 2978 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2979 the variables can also be restricted to IP address or MAC address. 2980 2981 The format of the list is: 2982 type_attribute = [s|d|x|b|i|m] 2983 access_attribute = [a|r|o|c] 2984 attributes = type_attribute[access_attribute] 2985 entry = variable_name[:attributes] 2986 list = entry[,list] 2987 2988 The type attributes are: 2989 s - String (default) 2990 d - Decimal 2991 x - Hexadecimal 2992 b - Boolean ([1yYtT|0nNfF]) 2993 i - IP address 2994 m - MAC address 2995 2996 The access attributes are: 2997 a - Any (default) 2998 r - Read-only 2999 o - Write-once 3000 c - Change-default 3001 3002 - CONFIG_ENV_FLAGS_LIST_DEFAULT 3003 Define this to a list (string) to define the ".flags" 3004 environment variable in the default or embedded environment. 3005 3006 - CONFIG_ENV_FLAGS_LIST_STATIC 3007 Define this to a list (string) to define validation that 3008 should be done if an entry is not found in the ".flags" 3009 environment variable. To override a setting in the static 3010 list, simply add an entry for the same variable name to the 3011 ".flags" variable. 3012 3013 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3014 regular expression. This allows multiple variables to define the same 3015 flags without explicitly listing them for each variable. 3016 3017- CONFIG_ENV_ACCESS_IGNORE_FORCE 3018 If defined, don't allow the -f switch to env set override variable 3019 access flags. 3020 3021- CONFIG_USE_STDINT 3022 If stdint.h is available with your toolchain you can define this 3023 option to enable it. You can provide option 'USE_STDINT=1' when 3024 building U-Boot to enable this. 3025 3026The following definitions that deal with the placement and management 3027of environment data (variable area); in general, we support the 3028following configurations: 3029 3030- CONFIG_BUILD_ENVCRC: 3031 3032 Builds up envcrc with the target environment so that external utils 3033 may easily extract it and embed it in final U-Boot images. 3034 3035BE CAREFUL! The first access to the environment happens quite early 3036in U-Boot initialization (when we try to get the setting of for the 3037console baudrate). You *MUST* have mapped your NVRAM area then, or 3038U-Boot will hang. 3039 3040Please note that even with NVRAM we still use a copy of the 3041environment in RAM: we could work on NVRAM directly, but we want to 3042keep settings there always unmodified except somebody uses "saveenv" 3043to save the current settings. 3044 3045BE CAREFUL! For some special cases, the local device can not use 3046"saveenv" command. For example, the local device will get the 3047environment stored in a remote NOR flash by SRIO or PCIE link, 3048but it can not erase, write this NOR flash by SRIO or PCIE interface. 3049 3050- CONFIG_NAND_ENV_DST 3051 3052 Defines address in RAM to which the nand_spl code should copy the 3053 environment. If redundant environment is used, it will be copied to 3054 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 3055 3056Please note that the environment is read-only until the monitor 3057has been relocated to RAM and a RAM copy of the environment has been 3058created; also, when using EEPROM you will have to use env_get_f() 3059until then to read environment variables. 3060 3061The environment is protected by a CRC32 checksum. Before the monitor 3062is relocated into RAM, as a result of a bad CRC you will be working 3063with the compiled-in default environment - *silently*!!! [This is 3064necessary, because the first environment variable we need is the 3065"baudrate" setting for the console - if we have a bad CRC, we don't 3066have any device yet where we could complain.] 3067 3068Note: once the monitor has been relocated, then it will complain if 3069the default environment is used; a new CRC is computed as soon as you 3070use the "saveenv" command to store a valid environment. 3071 3072- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 3073 Echo the inverted Ethernet link state to the fault LED. 3074 3075 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 3076 also needs to be defined. 3077 3078- CONFIG_SYS_FAULT_MII_ADDR: 3079 MII address of the PHY to check for the Ethernet link state. 3080 3081- CONFIG_NS16550_MIN_FUNCTIONS: 3082 Define this if you desire to only have use of the NS16550_init 3083 and NS16550_putc functions for the serial driver located at 3084 drivers/serial/ns16550.c. This option is useful for saving 3085 space for already greatly restricted images, including but not 3086 limited to NAND_SPL configurations. 3087 3088- CONFIG_DISPLAY_BOARDINFO 3089 Display information about the board that U-Boot is running on 3090 when U-Boot starts up. The board function checkboard() is called 3091 to do this. 3092 3093- CONFIG_DISPLAY_BOARDINFO_LATE 3094 Similar to the previous option, but display this information 3095 later, once stdio is running and output goes to the LCD, if 3096 present. 3097 3098- CONFIG_BOARD_SIZE_LIMIT: 3099 Maximum size of the U-Boot image. When defined, the 3100 build system checks that the actual size does not 3101 exceed it. 3102 3103Low Level (hardware related) configuration options: 3104--------------------------------------------------- 3105 3106- CONFIG_SYS_CACHELINE_SIZE: 3107 Cache Line Size of the CPU. 3108 3109- CONFIG_SYS_CCSRBAR_DEFAULT: 3110 Default (power-on reset) physical address of CCSR on Freescale 3111 PowerPC SOCs. 3112 3113- CONFIG_SYS_CCSRBAR: 3114 Virtual address of CCSR. On a 32-bit build, this is typically 3115 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 3116 3117- CONFIG_SYS_CCSRBAR_PHYS: 3118 Physical address of CCSR. CCSR can be relocated to a new 3119 physical address, if desired. In this case, this macro should 3120 be set to that address. Otherwise, it should be set to the 3121 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 3122 is typically relocated on 36-bit builds. It is recommended 3123 that this macro be defined via the _HIGH and _LOW macros: 3124 3125 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 3126 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 3127 3128- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 3129 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 3130 either 0 (32-bit build) or 0xF (36-bit build). This macro is 3131 used in assembly code, so it must not contain typecasts or 3132 integer size suffixes (e.g. "ULL"). 3133 3134- CONFIG_SYS_CCSRBAR_PHYS_LOW: 3135 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 3136 used in assembly code, so it must not contain typecasts or 3137 integer size suffixes (e.g. "ULL"). 3138 3139- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 3140 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 3141 forced to a value that ensures that CCSR is not relocated. 3142 3143- Floppy Disk Support: 3144 CONFIG_SYS_FDC_DRIVE_NUMBER 3145 3146 the default drive number (default value 0) 3147 3148 CONFIG_SYS_ISA_IO_STRIDE 3149 3150 defines the spacing between FDC chipset registers 3151 (default value 1) 3152 3153 CONFIG_SYS_ISA_IO_OFFSET 3154 3155 defines the offset of register from address. It 3156 depends on which part of the data bus is connected to 3157 the FDC chipset. (default value 0) 3158 3159 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and 3160 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their 3161 default value. 3162 3163 if CONFIG_SYS_FDC_HW_INIT is defined, then the function 3164 fdc_hw_init() is called at the beginning of the FDC 3165 setup. fdc_hw_init() must be provided by the board 3166 source code. It is used to make hardware-dependent 3167 initializations. 3168 3169- CONFIG_IDE_AHB: 3170 Most IDE controllers were designed to be connected with PCI 3171 interface. Only few of them were designed for AHB interface. 3172 When software is doing ATA command and data transfer to 3173 IDE devices through IDE-AHB controller, some additional 3174 registers accessing to these kind of IDE-AHB controller 3175 is required. 3176 3177- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 3178 DO NOT CHANGE unless you know exactly what you're 3179 doing! (11-4) [MPC8xx systems only] 3180 3181- CONFIG_SYS_INIT_RAM_ADDR: 3182 3183 Start address of memory area that can be used for 3184 initial data and stack; please note that this must be 3185 writable memory that is working WITHOUT special 3186 initialization, i. e. you CANNOT use normal RAM which 3187 will become available only after programming the 3188 memory controller and running certain initialization 3189 sequences. 3190 3191 U-Boot uses the following memory types: 3192 - MPC8xx: IMMR (internal memory of the CPU) 3193 3194- CONFIG_SYS_GBL_DATA_OFFSET: 3195 3196 Offset of the initial data structure in the memory 3197 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 3198 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 3199 data is located at the end of the available space 3200 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 3201 GENERATED_GBL_DATA_SIZE), and the initial stack is just 3202 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 3203 CONFIG_SYS_GBL_DATA_OFFSET) downward. 3204 3205 Note: 3206 On the MPC824X (or other systems that use the data 3207 cache for initial memory) the address chosen for 3208 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 3209 point to an otherwise UNUSED address space between 3210 the top of RAM and the start of the PCI space. 3211 3212- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 3213 3214- CONFIG_SYS_OR_TIMING_SDRAM: 3215 SDRAM timing 3216 3217- CONFIG_SYS_MAMR_PTA: 3218 periodic timer for refresh 3219 3220- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 3221 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 3222 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 3223 CONFIG_SYS_BR1_PRELIM: 3224 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 3225 3226- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 3227 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 3228 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 3229 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 3230 3231- CONFIG_PCI_ENUM_ONLY 3232 Only scan through and get the devices on the buses. 3233 Don't do any setup work, presumably because someone or 3234 something has already done it, and we don't need to do it 3235 a second time. Useful for platforms that are pre-booted 3236 by coreboot or similar. 3237 3238- CONFIG_PCI_INDIRECT_BRIDGE: 3239 Enable support for indirect PCI bridges. 3240 3241- CONFIG_SYS_SRIO: 3242 Chip has SRIO or not 3243 3244- CONFIG_SRIO1: 3245 Board has SRIO 1 port available 3246 3247- CONFIG_SRIO2: 3248 Board has SRIO 2 port available 3249 3250- CONFIG_SRIO_PCIE_BOOT_MASTER 3251 Board can support master function for Boot from SRIO and PCIE 3252 3253- CONFIG_SYS_SRIOn_MEM_VIRT: 3254 Virtual Address of SRIO port 'n' memory region 3255 3256- CONFIG_SYS_SRIOn_MEM_PHYS: 3257 Physical Address of SRIO port 'n' memory region 3258 3259- CONFIG_SYS_SRIOn_MEM_SIZE: 3260 Size of SRIO port 'n' memory region 3261 3262- CONFIG_SYS_NAND_BUSWIDTH_16BIT 3263 Defined to tell the NAND controller that the NAND chip is using 3264 a 16 bit bus. 3265 Not all NAND drivers use this symbol. 3266 Example of drivers that use it: 3267 - drivers/mtd/nand/ndfc.c 3268 - drivers/mtd/nand/mxc_nand.c 3269 3270- CONFIG_SYS_NDFC_EBC0_CFG 3271 Sets the EBC0_CFG register for the NDFC. If not defined 3272 a default value will be used. 3273 3274- CONFIG_SPD_EEPROM 3275 Get DDR timing information from an I2C EEPROM. Common 3276 with pluggable memory modules such as SODIMMs 3277 3278 SPD_EEPROM_ADDRESS 3279 I2C address of the SPD EEPROM 3280 3281- CONFIG_SYS_SPD_BUS_NUM 3282 If SPD EEPROM is on an I2C bus other than the first 3283 one, specify here. Note that the value must resolve 3284 to something your driver can deal with. 3285 3286- CONFIG_SYS_DDR_RAW_TIMING 3287 Get DDR timing information from other than SPD. Common with 3288 soldered DDR chips onboard without SPD. DDR raw timing 3289 parameters are extracted from datasheet and hard-coded into 3290 header files or board specific files. 3291 3292- CONFIG_FSL_DDR_INTERACTIVE 3293 Enable interactive DDR debugging. See doc/README.fsl-ddr. 3294 3295- CONFIG_FSL_DDR_SYNC_REFRESH 3296 Enable sync of refresh for multiple controllers. 3297 3298- CONFIG_FSL_DDR_BIST 3299 Enable built-in memory test for Freescale DDR controllers. 3300 3301- CONFIG_SYS_83XX_DDR_USES_CS0 3302 Only for 83xx systems. If specified, then DDR should 3303 be configured using CS0 and CS1 instead of CS2 and CS3. 3304 3305- CONFIG_RMII 3306 Enable RMII mode for all FECs. 3307 Note that this is a global option, we can't 3308 have one FEC in standard MII mode and another in RMII mode. 3309 3310- CONFIG_CRC32_VERIFY 3311 Add a verify option to the crc32 command. 3312 The syntax is: 3313 3314 => crc32 -v <address> <count> <crc32> 3315 3316 Where address/count indicate a memory area 3317 and crc32 is the correct crc32 which the 3318 area should have. 3319 3320- CONFIG_LOOPW 3321 Add the "loopw" memory command. This only takes effect if 3322 the memory commands are activated globally (CONFIG_CMD_MEMORY). 3323 3324- CONFIG_MX_CYCLIC 3325 Add the "mdc" and "mwc" memory commands. These are cyclic 3326 "md/mw" commands. 3327 Examples: 3328 3329 => mdc.b 10 4 500 3330 This command will print 4 bytes (10,11,12,13) each 500 ms. 3331 3332 => mwc.l 100 12345678 10 3333 This command will write 12345678 to address 100 all 10 ms. 3334 3335 This only takes effect if the memory commands are activated 3336 globally (CONFIG_CMD_MEMORY). 3337 3338- CONFIG_SKIP_LOWLEVEL_INIT 3339 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 3340 low level initializations (like setting up the memory 3341 controller) are omitted and/or U-Boot does not 3342 relocate itself into RAM. 3343 3344 Normally this variable MUST NOT be defined. The only 3345 exception is when U-Boot is loaded (to RAM) by some 3346 other boot loader or by a debugger which performs 3347 these initializations itself. 3348 3349- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 3350 [ARM926EJ-S only] This allows just the call to lowlevel_init() 3351 to be skipped. The normal CP15 init (such as enabling the 3352 instruction cache) is still performed. 3353 3354- CONFIG_SPL_BUILD 3355 Modifies the behaviour of start.S when compiling a loader 3356 that is executed before the actual U-Boot. E.g. when 3357 compiling a NAND SPL. 3358 3359- CONFIG_TPL_BUILD 3360 Modifies the behaviour of start.S when compiling a loader 3361 that is executed after the SPL and before the actual U-Boot. 3362 It is loaded by the SPL. 3363 3364- CONFIG_SYS_MPC85XX_NO_RESETVEC 3365 Only for 85xx systems. If this variable is specified, the section 3366 .resetvec is not kept and the section .bootpg is placed in the 3367 previous 4k of the .text section. 3368 3369- CONFIG_ARCH_MAP_SYSMEM 3370 Generally U-Boot (and in particular the md command) uses 3371 effective address. It is therefore not necessary to regard 3372 U-Boot address as virtual addresses that need to be translated 3373 to physical addresses. However, sandbox requires this, since 3374 it maintains its own little RAM buffer which contains all 3375 addressable memory. This option causes some memory accesses 3376 to be mapped through map_sysmem() / unmap_sysmem(). 3377 3378- CONFIG_X86_RESET_VECTOR 3379 If defined, the x86 reset vector code is included. This is not 3380 needed when U-Boot is running from Coreboot. 3381 3382- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 3383 Option to disable subpage write in NAND driver 3384 driver that uses this: 3385 drivers/mtd/nand/davinci_nand.c 3386 3387Freescale QE/FMAN Firmware Support: 3388----------------------------------- 3389 3390The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 3391loading of "firmware", which is encoded in the QE firmware binary format. 3392This firmware often needs to be loaded during U-Boot booting, so macros 3393are used to identify the storage device (NOR flash, SPI, etc) and the address 3394within that device. 3395 3396- CONFIG_SYS_FMAN_FW_ADDR 3397 The address in the storage device where the FMAN microcode is located. The 3398 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3399 is also specified. 3400 3401- CONFIG_SYS_QE_FW_ADDR 3402 The address in the storage device where the QE microcode is located. The 3403 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3404 is also specified. 3405 3406- CONFIG_SYS_QE_FMAN_FW_LENGTH 3407 The maximum possible size of the firmware. The firmware binary format 3408 has a field that specifies the actual size of the firmware, but it 3409 might not be possible to read any part of the firmware unless some 3410 local storage is allocated to hold the entire firmware first. 3411 3412- CONFIG_SYS_QE_FMAN_FW_IN_NOR 3413 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 3414 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 3415 virtual address in NOR flash. 3416 3417- CONFIG_SYS_QE_FMAN_FW_IN_NAND 3418 Specifies that QE/FMAN firmware is located in NAND flash. 3419 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 3420 3421- CONFIG_SYS_QE_FMAN_FW_IN_MMC 3422 Specifies that QE/FMAN firmware is located on the primary SD/MMC 3423 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 3424 3425- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 3426 Specifies that QE/FMAN firmware is located in the remote (master) 3427 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 3428 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 3429 window->master inbound window->master LAW->the ucode address in 3430 master's memory space. 3431 3432Freescale Layerscape Management Complex Firmware Support: 3433--------------------------------------------------------- 3434The Freescale Layerscape Management Complex (MC) supports the loading of 3435"firmware". 3436This firmware often needs to be loaded during U-Boot booting, so macros 3437are used to identify the storage device (NOR flash, SPI, etc) and the address 3438within that device. 3439 3440- CONFIG_FSL_MC_ENET 3441 Enable the MC driver for Layerscape SoCs. 3442 3443Freescale Layerscape Debug Server Support: 3444------------------------------------------- 3445The Freescale Layerscape Debug Server Support supports the loading of 3446"Debug Server firmware" and triggering SP boot-rom. 3447This firmware often needs to be loaded during U-Boot booting. 3448 3449- CONFIG_SYS_MC_RSV_MEM_ALIGN 3450 Define alignment of reserved memory MC requires 3451 3452Reproducible builds 3453------------------- 3454 3455In order to achieve reproducible builds, timestamps used in the U-Boot build 3456process have to be set to a fixed value. 3457 3458This is done using the SOURCE_DATE_EPOCH environment variable. 3459SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3460option for U-Boot or an environment variable in U-Boot. 3461 3462SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3463 3464Building the Software: 3465====================== 3466 3467Building U-Boot has been tested in several native build environments 3468and in many different cross environments. Of course we cannot support 3469all possibly existing versions of cross development tools in all 3470(potentially obsolete) versions. In case of tool chain problems we 3471recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) 3472which is extensively used to build and test U-Boot. 3473 3474If you are not using a native environment, it is assumed that you 3475have GNU cross compiling tools available in your path. In this case, 3476you must set the environment variable CROSS_COMPILE in your shell. 3477Note that no changes to the Makefile or any other source files are 3478necessary. For example using the ELDK on a 4xx CPU, please enter: 3479 3480 $ CROSS_COMPILE=ppc_4xx- 3481 $ export CROSS_COMPILE 3482 3483Note: If you wish to generate Windows versions of the utilities in 3484 the tools directory you can use the MinGW toolchain 3485 (http://www.mingw.org). Set your HOST tools to the MinGW 3486 toolchain and execute 'make tools'. For example: 3487 3488 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools 3489 3490 Binaries such as tools/mkimage.exe will be created which can 3491 be executed on computers running Windows. 3492 3493U-Boot is intended to be simple to build. After installing the 3494sources you must configure U-Boot for one specific board type. This 3495is done by typing: 3496 3497 make NAME_defconfig 3498 3499where "NAME_defconfig" is the name of one of the existing configu- 3500rations; see boards.cfg for supported names. 3501 3502Note: for some board special configuration names may exist; check if 3503 additional information is available from the board vendor; for 3504 instance, the TQM823L systems are available without (standard) 3505 or with LCD support. You can select such additional "features" 3506 when choosing the configuration, i. e. 3507 3508 make TQM823L_defconfig 3509 - will configure for a plain TQM823L, i. e. no LCD support 3510 3511 make TQM823L_LCD_defconfig 3512 - will configure for a TQM823L with U-Boot console on LCD 3513 3514 etc. 3515 3516 3517Finally, type "make all", and you should get some working U-Boot 3518images ready for download to / installation on your system: 3519 3520- "u-boot.bin" is a raw binary image 3521- "u-boot" is an image in ELF binary format 3522- "u-boot.srec" is in Motorola S-Record format 3523 3524By default the build is performed locally and the objects are saved 3525in the source directory. One of the two methods can be used to change 3526this behavior and build U-Boot to some external directory: 3527 35281. Add O= to the make command line invocations: 3529 3530 make O=/tmp/build distclean 3531 make O=/tmp/build NAME_defconfig 3532 make O=/tmp/build all 3533 35342. Set environment variable KBUILD_OUTPUT to point to the desired location: 3535 3536 export KBUILD_OUTPUT=/tmp/build 3537 make distclean 3538 make NAME_defconfig 3539 make all 3540 3541Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3542variable. 3543 3544User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3545setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3546For example to treat all compiler warnings as errors: 3547 3548 make KCFLAGS=-Werror 3549 3550Please be aware that the Makefiles assume you are using GNU make, so 3551for instance on NetBSD you might need to use "gmake" instead of 3552native "make". 3553 3554 3555If the system board that you have is not listed, then you will need 3556to port U-Boot to your hardware platform. To do this, follow these 3557steps: 3558 35591. Create a new directory to hold your board specific code. Add any 3560 files you need. In your board directory, you will need at least 3561 the "Makefile" and a "<board>.c". 35622. Create a new configuration file "include/configs/<board>.h" for 3563 your board. 35643. If you're porting U-Boot to a new CPU, then also create a new 3565 directory to hold your CPU specific code. Add any files you need. 35664. Run "make <board>_defconfig" with your new name. 35675. Type "make", and you should get a working "u-boot.srec" file 3568 to be installed on your target system. 35696. Debug and solve any problems that might arise. 3570 [Of course, this last step is much harder than it sounds.] 3571 3572 3573Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3574============================================================== 3575 3576If you have modified U-Boot sources (for instance added a new board 3577or support for new devices, a new CPU, etc.) you are expected to 3578provide feedback to the other developers. The feedback normally takes 3579the form of a "patch", i. e. a context diff against a certain (latest 3580official or latest in the git repository) version of U-Boot sources. 3581 3582But before you submit such a patch, please verify that your modifi- 3583cation did not break existing code. At least make sure that *ALL* of 3584the supported boards compile WITHOUT ANY compiler warnings. To do so, 3585just run the buildman script (tools/buildman/buildman), which will 3586configure and build U-Boot for ALL supported system. Be warned, this 3587will take a while. Please see the buildman README, or run 'buildman -H' 3588for documentation. 3589 3590 3591See also "U-Boot Porting Guide" below. 3592 3593 3594Monitor Commands - Overview: 3595============================ 3596 3597go - start application at address 'addr' 3598run - run commands in an environment variable 3599bootm - boot application image from memory 3600bootp - boot image via network using BootP/TFTP protocol 3601bootz - boot zImage from memory 3602tftpboot- boot image via network using TFTP protocol 3603 and env variables "ipaddr" and "serverip" 3604 (and eventually "gatewayip") 3605tftpput - upload a file via network using TFTP protocol 3606rarpboot- boot image via network using RARP/TFTP protocol 3607diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3608loads - load S-Record file over serial line 3609loadb - load binary file over serial line (kermit mode) 3610md - memory display 3611mm - memory modify (auto-incrementing) 3612nm - memory modify (constant address) 3613mw - memory write (fill) 3614cp - memory copy 3615cmp - memory compare 3616crc32 - checksum calculation 3617i2c - I2C sub-system 3618sspi - SPI utility commands 3619base - print or set address offset 3620printenv- print environment variables 3621setenv - set environment variables 3622saveenv - save environment variables to persistent storage 3623protect - enable or disable FLASH write protection 3624erase - erase FLASH memory 3625flinfo - print FLASH memory information 3626nand - NAND memory operations (see doc/README.nand) 3627bdinfo - print Board Info structure 3628iminfo - print header information for application image 3629coninfo - print console devices and informations 3630ide - IDE sub-system 3631loop - infinite loop on address range 3632loopw - infinite write loop on address range 3633mtest - simple RAM test 3634icache - enable or disable instruction cache 3635dcache - enable or disable data cache 3636reset - Perform RESET of the CPU 3637echo - echo args to console 3638version - print monitor version 3639help - print online help 3640? - alias for 'help' 3641 3642 3643Monitor Commands - Detailed Description: 3644======================================== 3645 3646TODO. 3647 3648For now: just type "help <command>". 3649 3650 3651Environment Variables: 3652====================== 3653 3654U-Boot supports user configuration using Environment Variables which 3655can be made persistent by saving to Flash memory. 3656 3657Environment Variables are set using "setenv", printed using 3658"printenv", and saved to Flash using "saveenv". Using "setenv" 3659without a value can be used to delete a variable from the 3660environment. As long as you don't save the environment you are 3661working with an in-memory copy. In case the Flash area containing the 3662environment is erased by accident, a default environment is provided. 3663 3664Some configuration options can be set using Environment Variables. 3665 3666List of environment variables (most likely not complete): 3667 3668 baudrate - see CONFIG_BAUDRATE 3669 3670 bootdelay - see CONFIG_BOOTDELAY 3671 3672 bootcmd - see CONFIG_BOOTCOMMAND 3673 3674 bootargs - Boot arguments when booting an RTOS image 3675 3676 bootfile - Name of the image to load with TFTP 3677 3678 bootm_low - Memory range available for image processing in the bootm 3679 command can be restricted. This variable is given as 3680 a hexadecimal number and defines lowest address allowed 3681 for use by the bootm command. See also "bootm_size" 3682 environment variable. Address defined by "bootm_low" is 3683 also the base of the initial memory mapping for the Linux 3684 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3685 bootm_mapsize. 3686 3687 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3688 This variable is given as a hexadecimal number and it 3689 defines the size of the memory region starting at base 3690 address bootm_low that is accessible by the Linux kernel 3691 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3692 as the default value if it is defined, and bootm_size is 3693 used otherwise. 3694 3695 bootm_size - Memory range available for image processing in the bootm 3696 command can be restricted. This variable is given as 3697 a hexadecimal number and defines the size of the region 3698 allowed for use by the bootm command. See also "bootm_low" 3699 environment variable. 3700 3701 updatefile - Location of the software update file on a TFTP server, used 3702 by the automatic software update feature. Please refer to 3703 documentation in doc/README.update for more details. 3704 3705 autoload - if set to "no" (any string beginning with 'n'), 3706 "bootp" will just load perform a lookup of the 3707 configuration from the BOOTP server, but not try to 3708 load any image using TFTP 3709 3710 autostart - if set to "yes", an image loaded using the "bootp", 3711 "rarpboot", "tftpboot" or "diskboot" commands will 3712 be automatically started (by internally calling 3713 "bootm") 3714 3715 If set to "no", a standalone image passed to the 3716 "bootm" command will be copied to the load address 3717 (and eventually uncompressed), but NOT be started. 3718 This can be used to load and uncompress arbitrary 3719 data. 3720 3721 fdt_high - if set this restricts the maximum address that the 3722 flattened device tree will be copied into upon boot. 3723 For example, if you have a system with 1 GB memory 3724 at physical address 0x10000000, while Linux kernel 3725 only recognizes the first 704 MB as low memory, you 3726 may need to set fdt_high as 0x3C000000 to have the 3727 device tree blob be copied to the maximum address 3728 of the 704 MB low memory, so that Linux kernel can 3729 access it during the boot procedure. 3730 3731 If this is set to the special value 0xFFFFFFFF then 3732 the fdt will not be copied at all on boot. For this 3733 to work it must reside in writable memory, have 3734 sufficient padding on the end of it for u-boot to 3735 add the information it needs into it, and the memory 3736 must be accessible by the kernel. 3737 3738 fdtcontroladdr- if set this is the address of the control flattened 3739 device tree used by U-Boot when CONFIG_OF_CONTROL is 3740 defined. 3741 3742 i2cfast - (PPC405GP|PPC405EP only) 3743 if set to 'y' configures Linux I2C driver for fast 3744 mode (400kHZ). This environment variable is used in 3745 initialization code. So, for changes to be effective 3746 it must be saved and board must be reset. 3747 3748 initrd_high - restrict positioning of initrd images: 3749 If this variable is not set, initrd images will be 3750 copied to the highest possible address in RAM; this 3751 is usually what you want since it allows for 3752 maximum initrd size. If for some reason you want to 3753 make sure that the initrd image is loaded below the 3754 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3755 variable to a value of "no" or "off" or "0". 3756 Alternatively, you can set it to a maximum upper 3757 address to use (U-Boot will still check that it 3758 does not overwrite the U-Boot stack and data). 3759 3760 For instance, when you have a system with 16 MB 3761 RAM, and want to reserve 4 MB from use by Linux, 3762 you can do this by adding "mem=12M" to the value of 3763 the "bootargs" variable. However, now you must make 3764 sure that the initrd image is placed in the first 3765 12 MB as well - this can be done with 3766 3767 setenv initrd_high 00c00000 3768 3769 If you set initrd_high to 0xFFFFFFFF, this is an 3770 indication to U-Boot that all addresses are legal 3771 for the Linux kernel, including addresses in flash 3772 memory. In this case U-Boot will NOT COPY the 3773 ramdisk at all. This may be useful to reduce the 3774 boot time on your system, but requires that this 3775 feature is supported by your Linux kernel. 3776 3777 ipaddr - IP address; needed for tftpboot command 3778 3779 loadaddr - Default load address for commands like "bootp", 3780 "rarpboot", "tftpboot", "loadb" or "diskboot" 3781 3782 loads_echo - see CONFIG_LOADS_ECHO 3783 3784 serverip - TFTP server IP address; needed for tftpboot command 3785 3786 bootretry - see CONFIG_BOOT_RETRY_TIME 3787 3788 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3789 3790 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3791 3792 ethprime - controls which interface is used first. 3793 3794 ethact - controls which interface is currently active. 3795 For example you can do the following 3796 3797 => setenv ethact FEC 3798 => ping 192.168.0.1 # traffic sent on FEC 3799 => setenv ethact SCC 3800 => ping 10.0.0.1 # traffic sent on SCC 3801 3802 ethrotate - When set to "no" U-Boot does not go through all 3803 available network interfaces. 3804 It just stays at the currently selected interface. 3805 3806 netretry - When set to "no" each network operation will 3807 either succeed or fail without retrying. 3808 When set to "once" the network operation will 3809 fail when all the available network interfaces 3810 are tried once without success. 3811 Useful on scripts which control the retry operation 3812 themselves. 3813 3814 npe_ucode - set load address for the NPE microcode 3815 3816 silent_linux - If set then Linux will be told to boot silently, by 3817 changing the console to be empty. If "yes" it will be 3818 made silent. If "no" it will not be made silent. If 3819 unset, then it will be made silent if the U-Boot console 3820 is silent. 3821 3822 tftpsrcp - If this is set, the value is used for TFTP's 3823 UDP source port. 3824 3825 tftpdstp - If this is set, the value is used for TFTP's UDP 3826 destination port instead of the Well Know Port 69. 3827 3828 tftpblocksize - Block size to use for TFTP transfers; if not set, 3829 we use the TFTP server's default block size 3830 3831 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3832 seconds, minimum value is 1000 = 1 second). Defines 3833 when a packet is considered to be lost so it has to 3834 be retransmitted. The default is 5000 = 5 seconds. 3835 Lowering this value may make downloads succeed 3836 faster in networks with high packet loss rates or 3837 with unreliable TFTP servers. 3838 3839 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3840 unit, minimum value = 0). Defines how many timeouts 3841 can happen during a single file transfer before that 3842 transfer is aborted. The default is 10, and 0 means 3843 'no timeouts allowed'. Increasing this value may help 3844 downloads succeed with high packet loss rates, or with 3845 unreliable TFTP servers or client hardware. 3846 3847 vlan - When set to a value < 4095 the traffic over 3848 Ethernet is encapsulated/received over 802.1q 3849 VLAN tagged frames. 3850 3851 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3852 Unsigned value, in milliseconds. If not set, the period will 3853 be either the default (28000), or a value based on 3854 CONFIG_NET_RETRY_COUNT, if defined. This value has 3855 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3856 3857The following image location variables contain the location of images 3858used in booting. The "Image" column gives the role of the image and is 3859not an environment variable name. The other columns are environment 3860variable names. "File Name" gives the name of the file on a TFTP 3861server, "RAM Address" gives the location in RAM the image will be 3862loaded to, and "Flash Location" gives the image's address in NOR 3863flash or offset in NAND flash. 3864 3865*Note* - these variables don't have to be defined for all boards, some 3866boards currently use other variables for these purposes, and some 3867boards use these variables for other purposes. 3868 3869Image File Name RAM Address Flash Location 3870----- --------- ----------- -------------- 3871u-boot u-boot u-boot_addr_r u-boot_addr 3872Linux kernel bootfile kernel_addr_r kernel_addr 3873device tree blob fdtfile fdt_addr_r fdt_addr 3874ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3875 3876The following environment variables may be used and automatically 3877updated by the network boot commands ("bootp" and "rarpboot"), 3878depending the information provided by your boot server: 3879 3880 bootfile - see above 3881 dnsip - IP address of your Domain Name Server 3882 dnsip2 - IP address of your secondary Domain Name Server 3883 gatewayip - IP address of the Gateway (Router) to use 3884 hostname - Target hostname 3885 ipaddr - see above 3886 netmask - Subnet Mask 3887 rootpath - Pathname of the root filesystem on the NFS server 3888 serverip - see above 3889 3890 3891There are two special Environment Variables: 3892 3893 serial# - contains hardware identification information such 3894 as type string and/or serial number 3895 ethaddr - Ethernet address 3896 3897These variables can be set only once (usually during manufacturing of 3898the board). U-Boot refuses to delete or overwrite these variables 3899once they have been set once. 3900 3901 3902Further special Environment Variables: 3903 3904 ver - Contains the U-Boot version string as printed 3905 with the "version" command. This variable is 3906 readonly (see CONFIG_VERSION_VARIABLE). 3907 3908 3909Please note that changes to some configuration parameters may take 3910only effect after the next boot (yes, that's just like Windoze :-). 3911 3912 3913Callback functions for environment variables: 3914--------------------------------------------- 3915 3916For some environment variables, the behavior of u-boot needs to change 3917when their values are changed. This functionality allows functions to 3918be associated with arbitrary variables. On creation, overwrite, or 3919deletion, the callback will provide the opportunity for some side 3920effect to happen or for the change to be rejected. 3921 3922The callbacks are named and associated with a function using the 3923U_BOOT_ENV_CALLBACK macro in your board or driver code. 3924 3925These callbacks are associated with variables in one of two ways. The 3926static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3927in the board configuration to a string that defines a list of 3928associations. The list must be in the following format: 3929 3930 entry = variable_name[:callback_name] 3931 list = entry[,list] 3932 3933If the callback name is not specified, then the callback is deleted. 3934Spaces are also allowed anywhere in the list. 3935 3936Callbacks can also be associated by defining the ".callbacks" variable 3937with the same list format above. Any association in ".callbacks" will 3938override any association in the static list. You can define 3939CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3940".callbacks" environment variable in the default or embedded environment. 3941 3942If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3943regular expression. This allows multiple variables to be connected to 3944the same callback without explicitly listing them all out. 3945 3946 3947Command Line Parsing: 3948===================== 3949 3950There are two different command line parsers available with U-Boot: 3951the old "simple" one, and the much more powerful "hush" shell: 3952 3953Old, simple command line parser: 3954-------------------------------- 3955 3956- supports environment variables (through setenv / saveenv commands) 3957- several commands on one line, separated by ';' 3958- variable substitution using "... ${name} ..." syntax 3959- special characters ('$', ';') can be escaped by prefixing with '\', 3960 for example: 3961 setenv bootcmd bootm \${address} 3962- You can also escape text by enclosing in single apostrophes, for example: 3963 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 3964 3965Hush shell: 3966----------- 3967 3968- similar to Bourne shell, with control structures like 3969 if...then...else...fi, for...do...done; while...do...done, 3970 until...do...done, ... 3971- supports environment ("global") variables (through setenv / saveenv 3972 commands) and local shell variables (through standard shell syntax 3973 "name=value"); only environment variables can be used with "run" 3974 command 3975 3976General rules: 3977-------------- 3978 3979(1) If a command line (or an environment variable executed by a "run" 3980 command) contains several commands separated by semicolon, and 3981 one of these commands fails, then the remaining commands will be 3982 executed anyway. 3983 3984(2) If you execute several variables with one call to run (i. e. 3985 calling run with a list of variables as arguments), any failing 3986 command will cause "run" to terminate, i. e. the remaining 3987 variables are not executed. 3988 3989Note for Redundant Ethernet Interfaces: 3990======================================= 3991 3992Some boards come with redundant Ethernet interfaces; U-Boot supports 3993such configurations and is capable of automatic selection of a 3994"working" interface when needed. MAC assignment works as follows: 3995 3996Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 3997MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 3998"eth1addr" (=>eth1), "eth2addr", ... 3999 4000If the network interface stores some valid MAC address (for instance 4001in SROM), this is used as default address if there is NO correspon- 4002ding setting in the environment; if the corresponding environment 4003variable is set, this overrides the settings in the card; that means: 4004 4005o If the SROM has a valid MAC address, and there is no address in the 4006 environment, the SROM's address is used. 4007 4008o If there is no valid address in the SROM, and a definition in the 4009 environment exists, then the value from the environment variable is 4010 used. 4011 4012o If both the SROM and the environment contain a MAC address, and 4013 both addresses are the same, this MAC address is used. 4014 4015o If both the SROM and the environment contain a MAC address, and the 4016 addresses differ, the value from the environment is used and a 4017 warning is printed. 4018 4019o If neither SROM nor the environment contain a MAC address, an error 4020 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 4021 a random, locally-assigned MAC is used. 4022 4023If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 4024will be programmed into hardware as part of the initialization process. This 4025may be skipped by setting the appropriate 'ethmacskip' environment variable. 4026The naming convention is as follows: 4027"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 4028 4029Image Formats: 4030============== 4031 4032U-Boot is capable of booting (and performing other auxiliary operations on) 4033images in two formats: 4034 4035New uImage format (FIT) 4036----------------------- 4037 4038Flexible and powerful format based on Flattened Image Tree -- FIT (similar 4039to Flattened Device Tree). It allows the use of images with multiple 4040components (several kernels, ramdisks, etc.), with contents protected by 4041SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 4042 4043 4044Old uImage format 4045----------------- 4046 4047Old image format is based on binary files which can be basically anything, 4048preceded by a special header; see the definitions in include/image.h for 4049details; basically, the header defines the following image properties: 4050 4051* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 4052 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 4053 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 4054 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 4055 INTEGRITY). 4056* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 4057 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 4058 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 4059* Compression Type (uncompressed, gzip, bzip2) 4060* Load Address 4061* Entry Point 4062* Image Name 4063* Image Timestamp 4064 4065The header is marked by a special Magic Number, and both the header 4066and the data portions of the image are secured against corruption by 4067CRC32 checksums. 4068 4069 4070Linux Support: 4071============== 4072 4073Although U-Boot should support any OS or standalone application 4074easily, the main focus has always been on Linux during the design of 4075U-Boot. 4076 4077U-Boot includes many features that so far have been part of some 4078special "boot loader" code within the Linux kernel. Also, any 4079"initrd" images to be used are no longer part of one big Linux image; 4080instead, kernel and "initrd" are separate images. This implementation 4081serves several purposes: 4082 4083- the same features can be used for other OS or standalone 4084 applications (for instance: using compressed images to reduce the 4085 Flash memory footprint) 4086 4087- it becomes much easier to port new Linux kernel versions because 4088 lots of low-level, hardware dependent stuff are done by U-Boot 4089 4090- the same Linux kernel image can now be used with different "initrd" 4091 images; of course this also means that different kernel images can 4092 be run with the same "initrd". This makes testing easier (you don't 4093 have to build a new "zImage.initrd" Linux image when you just 4094 change a file in your "initrd"). Also, a field-upgrade of the 4095 software is easier now. 4096 4097 4098Linux HOWTO: 4099============ 4100 4101Porting Linux to U-Boot based systems: 4102--------------------------------------- 4103 4104U-Boot cannot save you from doing all the necessary modifications to 4105configure the Linux device drivers for use with your target hardware 4106(no, we don't intend to provide a full virtual machine interface to 4107Linux :-). 4108 4109But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 4110 4111Just make sure your machine specific header file (for instance 4112include/asm-ppc/tqm8xx.h) includes the same definition of the Board 4113Information structure as we define in include/asm-<arch>/u-boot.h, 4114and make sure that your definition of IMAP_ADDR uses the same value 4115as your U-Boot configuration in CONFIG_SYS_IMMR. 4116 4117Note that U-Boot now has a driver model, a unified model for drivers. 4118If you are adding a new driver, plumb it into driver model. If there 4119is no uclass available, you are encouraged to create one. See 4120doc/driver-model. 4121 4122 4123Configuring the Linux kernel: 4124----------------------------- 4125 4126No specific requirements for U-Boot. Make sure you have some root 4127device (initial ramdisk, NFS) for your target system. 4128 4129 4130Building a Linux Image: 4131----------------------- 4132 4133With U-Boot, "normal" build targets like "zImage" or "bzImage" are 4134not used. If you use recent kernel source, a new build target 4135"uImage" will exist which automatically builds an image usable by 4136U-Boot. Most older kernels also have support for a "pImage" target, 4137which was introduced for our predecessor project PPCBoot and uses a 4138100% compatible format. 4139 4140Example: 4141 4142 make TQM850L_defconfig 4143 make oldconfig 4144 make dep 4145 make uImage 4146 4147The "uImage" build target uses a special tool (in 'tools/mkimage') to 4148encapsulate a compressed Linux kernel image with header information, 4149CRC32 checksum etc. for use with U-Boot. This is what we are doing: 4150 4151* build a standard "vmlinux" kernel image (in ELF binary format): 4152 4153* convert the kernel into a raw binary image: 4154 4155 ${CROSS_COMPILE}-objcopy -O binary \ 4156 -R .note -R .comment \ 4157 -S vmlinux linux.bin 4158 4159* compress the binary image: 4160 4161 gzip -9 linux.bin 4162 4163* package compressed binary image for U-Boot: 4164 4165 mkimage -A ppc -O linux -T kernel -C gzip \ 4166 -a 0 -e 0 -n "Linux Kernel Image" \ 4167 -d linux.bin.gz uImage 4168 4169 4170The "mkimage" tool can also be used to create ramdisk images for use 4171with U-Boot, either separated from the Linux kernel image, or 4172combined into one file. "mkimage" encapsulates the images with a 64 4173byte header containing information about target architecture, 4174operating system, image type, compression method, entry points, time 4175stamp, CRC32 checksums, etc. 4176 4177"mkimage" can be called in two ways: to verify existing images and 4178print the header information, or to build new images. 4179 4180In the first form (with "-l" option) mkimage lists the information 4181contained in the header of an existing U-Boot image; this includes 4182checksum verification: 4183 4184 tools/mkimage -l image 4185 -l ==> list image header information 4186 4187The second form (with "-d" option) is used to build a U-Boot image 4188from a "data file" which is used as image payload: 4189 4190 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 4191 -n name -d data_file image 4192 -A ==> set architecture to 'arch' 4193 -O ==> set operating system to 'os' 4194 -T ==> set image type to 'type' 4195 -C ==> set compression type 'comp' 4196 -a ==> set load address to 'addr' (hex) 4197 -e ==> set entry point to 'ep' (hex) 4198 -n ==> set image name to 'name' 4199 -d ==> use image data from 'datafile' 4200 4201Right now, all Linux kernels for PowerPC systems use the same load 4202address (0x00000000), but the entry point address depends on the 4203kernel version: 4204 4205- 2.2.x kernels have the entry point at 0x0000000C, 4206- 2.3.x and later kernels have the entry point at 0x00000000. 4207 4208So a typical call to build a U-Boot image would read: 4209 4210 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4211 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 4212 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 4213 > examples/uImage.TQM850L 4214 Image Name: 2.4.4 kernel for TQM850L 4215 Created: Wed Jul 19 02:34:59 2000 4216 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4217 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4218 Load Address: 0x00000000 4219 Entry Point: 0x00000000 4220 4221To verify the contents of the image (or check for corruption): 4222 4223 -> tools/mkimage -l examples/uImage.TQM850L 4224 Image Name: 2.4.4 kernel for TQM850L 4225 Created: Wed Jul 19 02:34:59 2000 4226 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4227 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4228 Load Address: 0x00000000 4229 Entry Point: 0x00000000 4230 4231NOTE: for embedded systems where boot time is critical you can trade 4232speed for memory and install an UNCOMPRESSED image instead: this 4233needs more space in Flash, but boots much faster since it does not 4234need to be uncompressed: 4235 4236 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 4237 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4238 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 4239 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 4240 > examples/uImage.TQM850L-uncompressed 4241 Image Name: 2.4.4 kernel for TQM850L 4242 Created: Wed Jul 19 02:34:59 2000 4243 Image Type: PowerPC Linux Kernel Image (uncompressed) 4244 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 4245 Load Address: 0x00000000 4246 Entry Point: 0x00000000 4247 4248 4249Similar you can build U-Boot images from a 'ramdisk.image.gz' file 4250when your kernel is intended to use an initial ramdisk: 4251 4252 -> tools/mkimage -n 'Simple Ramdisk Image' \ 4253 > -A ppc -O linux -T ramdisk -C gzip \ 4254 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 4255 Image Name: Simple Ramdisk Image 4256 Created: Wed Jan 12 14:01:50 2000 4257 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4258 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 4259 Load Address: 0x00000000 4260 Entry Point: 0x00000000 4261 4262The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i" 4263option performs the converse operation of the mkimage's second form (the "-d" 4264option). Given an image built by mkimage, the dumpimage extracts a "data file" 4265from the image: 4266 4267 tools/dumpimage -i image -T type -p position data_file 4268 -i ==> extract from the 'image' a specific 'data_file' 4269 -T ==> set image type to 'type' 4270 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image' 4271 4272 4273Installing a Linux Image: 4274------------------------- 4275 4276To downloading a U-Boot image over the serial (console) interface, 4277you must convert the image to S-Record format: 4278 4279 objcopy -I binary -O srec examples/image examples/image.srec 4280 4281The 'objcopy' does not understand the information in the U-Boot 4282image header, so the resulting S-Record file will be relative to 4283address 0x00000000. To load it to a given address, you need to 4284specify the target address as 'offset' parameter with the 'loads' 4285command. 4286 4287Example: install the image to address 0x40100000 (which on the 4288TQM8xxL is in the first Flash bank): 4289 4290 => erase 40100000 401FFFFF 4291 4292 .......... done 4293 Erased 8 sectors 4294 4295 => loads 40100000 4296 ## Ready for S-Record download ... 4297 ~>examples/image.srec 4298 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 4299 ... 4300 15989 15990 15991 15992 4301 [file transfer complete] 4302 [connected] 4303 ## Start Addr = 0x00000000 4304 4305 4306You can check the success of the download using the 'iminfo' command; 4307this includes a checksum verification so you can be sure no data 4308corruption happened: 4309 4310 => imi 40100000 4311 4312 ## Checking Image at 40100000 ... 4313 Image Name: 2.2.13 for initrd on TQM850L 4314 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4315 Data Size: 335725 Bytes = 327 kB = 0 MB 4316 Load Address: 00000000 4317 Entry Point: 0000000c 4318 Verifying Checksum ... OK 4319 4320 4321Boot Linux: 4322----------- 4323 4324The "bootm" command is used to boot an application that is stored in 4325memory (RAM or Flash). In case of a Linux kernel image, the contents 4326of the "bootargs" environment variable is passed to the kernel as 4327parameters. You can check and modify this variable using the 4328"printenv" and "setenv" commands: 4329 4330 4331 => printenv bootargs 4332 bootargs=root=/dev/ram 4333 4334 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4335 4336 => printenv bootargs 4337 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4338 4339 => bootm 40020000 4340 ## Booting Linux kernel at 40020000 ... 4341 Image Name: 2.2.13 for NFS on TQM850L 4342 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4343 Data Size: 381681 Bytes = 372 kB = 0 MB 4344 Load Address: 00000000 4345 Entry Point: 0000000c 4346 Verifying Checksum ... OK 4347 Uncompressing Kernel Image ... OK 4348 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 4349 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4350 time_init: decrementer frequency = 187500000/60 4351 Calibrating delay loop... 49.77 BogoMIPS 4352 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 4353 ... 4354 4355If you want to boot a Linux kernel with initial RAM disk, you pass 4356the memory addresses of both the kernel and the initrd image (PPBCOOT 4357format!) to the "bootm" command: 4358 4359 => imi 40100000 40200000 4360 4361 ## Checking Image at 40100000 ... 4362 Image Name: 2.2.13 for initrd on TQM850L 4363 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4364 Data Size: 335725 Bytes = 327 kB = 0 MB 4365 Load Address: 00000000 4366 Entry Point: 0000000c 4367 Verifying Checksum ... OK 4368 4369 ## Checking Image at 40200000 ... 4370 Image Name: Simple Ramdisk Image 4371 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4372 Data Size: 566530 Bytes = 553 kB = 0 MB 4373 Load Address: 00000000 4374 Entry Point: 00000000 4375 Verifying Checksum ... OK 4376 4377 => bootm 40100000 40200000 4378 ## Booting Linux kernel at 40100000 ... 4379 Image Name: 2.2.13 for initrd on TQM850L 4380 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4381 Data Size: 335725 Bytes = 327 kB = 0 MB 4382 Load Address: 00000000 4383 Entry Point: 0000000c 4384 Verifying Checksum ... OK 4385 Uncompressing Kernel Image ... OK 4386 ## Loading RAMDisk Image at 40200000 ... 4387 Image Name: Simple Ramdisk Image 4388 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4389 Data Size: 566530 Bytes = 553 kB = 0 MB 4390 Load Address: 00000000 4391 Entry Point: 00000000 4392 Verifying Checksum ... OK 4393 Loading Ramdisk ... OK 4394 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 4395 Boot arguments: root=/dev/ram 4396 time_init: decrementer frequency = 187500000/60 4397 Calibrating delay loop... 49.77 BogoMIPS 4398 ... 4399 RAMDISK: Compressed image found at block 0 4400 VFS: Mounted root (ext2 filesystem). 4401 4402 bash# 4403 4404Boot Linux and pass a flat device tree: 4405----------- 4406 4407First, U-Boot must be compiled with the appropriate defines. See the section 4408titled "Linux Kernel Interface" above for a more in depth explanation. The 4409following is an example of how to start a kernel and pass an updated 4410flat device tree: 4411 4412=> print oftaddr 4413oftaddr=0x300000 4414=> print oft 4415oft=oftrees/mpc8540ads.dtb 4416=> tftp $oftaddr $oft 4417Speed: 1000, full duplex 4418Using TSEC0 device 4419TFTP from server 192.168.1.1; our IP address is 192.168.1.101 4420Filename 'oftrees/mpc8540ads.dtb'. 4421Load address: 0x300000 4422Loading: # 4423done 4424Bytes transferred = 4106 (100a hex) 4425=> tftp $loadaddr $bootfile 4426Speed: 1000, full duplex 4427Using TSEC0 device 4428TFTP from server 192.168.1.1; our IP address is 192.168.1.2 4429Filename 'uImage'. 4430Load address: 0x200000 4431Loading:############ 4432done 4433Bytes transferred = 1029407 (fb51f hex) 4434=> print loadaddr 4435loadaddr=200000 4436=> print oftaddr 4437oftaddr=0x300000 4438=> bootm $loadaddr - $oftaddr 4439## Booting image at 00200000 ... 4440 Image Name: Linux-2.6.17-dirty 4441 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4442 Data Size: 1029343 Bytes = 1005.2 kB 4443 Load Address: 00000000 4444 Entry Point: 00000000 4445 Verifying Checksum ... OK 4446 Uncompressing Kernel Image ... OK 4447Booting using flat device tree at 0x300000 4448Using MPC85xx ADS machine description 4449Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 4450[snip] 4451 4452 4453More About U-Boot Image Types: 4454------------------------------ 4455 4456U-Boot supports the following image types: 4457 4458 "Standalone Programs" are directly runnable in the environment 4459 provided by U-Boot; it is expected that (if they behave 4460 well) you can continue to work in U-Boot after return from 4461 the Standalone Program. 4462 "OS Kernel Images" are usually images of some Embedded OS which 4463 will take over control completely. Usually these programs 4464 will install their own set of exception handlers, device 4465 drivers, set up the MMU, etc. - this means, that you cannot 4466 expect to re-enter U-Boot except by resetting the CPU. 4467 "RAMDisk Images" are more or less just data blocks, and their 4468 parameters (address, size) are passed to an OS kernel that is 4469 being started. 4470 "Multi-File Images" contain several images, typically an OS 4471 (Linux) kernel image and one or more data images like 4472 RAMDisks. This construct is useful for instance when you want 4473 to boot over the network using BOOTP etc., where the boot 4474 server provides just a single image file, but you want to get 4475 for instance an OS kernel and a RAMDisk image. 4476 4477 "Multi-File Images" start with a list of image sizes, each 4478 image size (in bytes) specified by an "uint32_t" in network 4479 byte order. This list is terminated by an "(uint32_t)0". 4480 Immediately after the terminating 0 follow the images, one by 4481 one, all aligned on "uint32_t" boundaries (size rounded up to 4482 a multiple of 4 bytes). 4483 4484 "Firmware Images" are binary images containing firmware (like 4485 U-Boot or FPGA images) which usually will be programmed to 4486 flash memory. 4487 4488 "Script files" are command sequences that will be executed by 4489 U-Boot's command interpreter; this feature is especially 4490 useful when you configure U-Boot to use a real shell (hush) 4491 as command interpreter. 4492 4493Booting the Linux zImage: 4494------------------------- 4495 4496On some platforms, it's possible to boot Linux zImage. This is done 4497using the "bootz" command. The syntax of "bootz" command is the same 4498as the syntax of "bootm" command. 4499 4500Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4501kernel with raw initrd images. The syntax is slightly different, the 4502address of the initrd must be augmented by it's size, in the following 4503format: "<initrd addres>:<initrd size>". 4504 4505 4506Standalone HOWTO: 4507================= 4508 4509One of the features of U-Boot is that you can dynamically load and 4510run "standalone" applications, which can use some resources of 4511U-Boot like console I/O functions or interrupt services. 4512 4513Two simple examples are included with the sources: 4514 4515"Hello World" Demo: 4516------------------- 4517 4518'examples/hello_world.c' contains a small "Hello World" Demo 4519application; it is automatically compiled when you build U-Boot. 4520It's configured to run at address 0x00040004, so you can play with it 4521like that: 4522 4523 => loads 4524 ## Ready for S-Record download ... 4525 ~>examples/hello_world.srec 4526 1 2 3 4 5 6 7 8 9 10 11 ... 4527 [file transfer complete] 4528 [connected] 4529 ## Start Addr = 0x00040004 4530 4531 => go 40004 Hello World! This is a test. 4532 ## Starting application at 0x00040004 ... 4533 Hello World 4534 argc = 7 4535 argv[0] = "40004" 4536 argv[1] = "Hello" 4537 argv[2] = "World!" 4538 argv[3] = "This" 4539 argv[4] = "is" 4540 argv[5] = "a" 4541 argv[6] = "test." 4542 argv[7] = "<NULL>" 4543 Hit any key to exit ... 4544 4545 ## Application terminated, rc = 0x0 4546 4547Another example, which demonstrates how to register a CPM interrupt 4548handler with the U-Boot code, can be found in 'examples/timer.c'. 4549Here, a CPM timer is set up to generate an interrupt every second. 4550The interrupt service routine is trivial, just printing a '.' 4551character, but this is just a demo program. The application can be 4552controlled by the following keys: 4553 4554 ? - print current values og the CPM Timer registers 4555 b - enable interrupts and start timer 4556 e - stop timer and disable interrupts 4557 q - quit application 4558 4559 => loads 4560 ## Ready for S-Record download ... 4561 ~>examples/timer.srec 4562 1 2 3 4 5 6 7 8 9 10 11 ... 4563 [file transfer complete] 4564 [connected] 4565 ## Start Addr = 0x00040004 4566 4567 => go 40004 4568 ## Starting application at 0x00040004 ... 4569 TIMERS=0xfff00980 4570 Using timer 1 4571 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4572 4573Hit 'b': 4574 [q, b, e, ?] Set interval 1000000 us 4575 Enabling timer 4576Hit '?': 4577 [q, b, e, ?] ........ 4578 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4579Hit '?': 4580 [q, b, e, ?] . 4581 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4582Hit '?': 4583 [q, b, e, ?] . 4584 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4585Hit '?': 4586 [q, b, e, ?] . 4587 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4588Hit 'e': 4589 [q, b, e, ?] ...Stopping timer 4590Hit 'q': 4591 [q, b, e, ?] ## Application terminated, rc = 0x0 4592 4593 4594Minicom warning: 4595================ 4596 4597Over time, many people have reported problems when trying to use the 4598"minicom" terminal emulation program for serial download. I (wd) 4599consider minicom to be broken, and recommend not to use it. Under 4600Unix, I recommend to use C-Kermit for general purpose use (and 4601especially for kermit binary protocol download ("loadb" command), and 4602use "cu" for S-Record download ("loads" command). See 4603http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4604for help with kermit. 4605 4606 4607Nevertheless, if you absolutely want to use it try adding this 4608configuration to your "File transfer protocols" section: 4609 4610 Name Program Name U/D FullScr IO-Red. Multi 4611 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4612 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4613 4614 4615NetBSD Notes: 4616============= 4617 4618Starting at version 0.9.2, U-Boot supports NetBSD both as host 4619(build U-Boot) and target system (boots NetBSD/mpc8xx). 4620 4621Building requires a cross environment; it is known to work on 4622NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4623need gmake since the Makefiles are not compatible with BSD make). 4624Note that the cross-powerpc package does not install include files; 4625attempting to build U-Boot will fail because <machine/ansi.h> is 4626missing. This file has to be installed and patched manually: 4627 4628 # cd /usr/pkg/cross/powerpc-netbsd/include 4629 # mkdir powerpc 4630 # ln -s powerpc machine 4631 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4632 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4633 4634Native builds *don't* work due to incompatibilities between native 4635and U-Boot include files. 4636 4637Booting assumes that (the first part of) the image booted is a 4638stage-2 loader which in turn loads and then invokes the kernel 4639proper. Loader sources will eventually appear in the NetBSD source 4640tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4641meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4642 4643 4644Implementation Internals: 4645========================= 4646 4647The following is not intended to be a complete description of every 4648implementation detail. However, it should help to understand the 4649inner workings of U-Boot and make it easier to port it to custom 4650hardware. 4651 4652 4653Initial Stack, Global Data: 4654--------------------------- 4655 4656The implementation of U-Boot is complicated by the fact that U-Boot 4657starts running out of ROM (flash memory), usually without access to 4658system RAM (because the memory controller is not initialized yet). 4659This means that we don't have writable Data or BSS segments, and BSS 4660is not initialized as zero. To be able to get a C environment working 4661at all, we have to allocate at least a minimal stack. Implementation 4662options for this are defined and restricted by the CPU used: Some CPU 4663models provide on-chip memory (like the IMMR area on MPC8xx and 4664MPC826x processors), on others (parts of) the data cache can be 4665locked as (mis-) used as memory, etc. 4666 4667 Chris Hallinan posted a good summary of these issues to the 4668 U-Boot mailing list: 4669 4670 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4671 From: "Chris Hallinan" <clh@net1plus.com> 4672 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4673 ... 4674 4675 Correct me if I'm wrong, folks, but the way I understand it 4676 is this: Using DCACHE as initial RAM for Stack, etc, does not 4677 require any physical RAM backing up the cache. The cleverness 4678 is that the cache is being used as a temporary supply of 4679 necessary storage before the SDRAM controller is setup. It's 4680 beyond the scope of this list to explain the details, but you 4681 can see how this works by studying the cache architecture and 4682 operation in the architecture and processor-specific manuals. 4683 4684 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4685 is another option for the system designer to use as an 4686 initial stack/RAM area prior to SDRAM being available. Either 4687 option should work for you. Using CS 4 should be fine if your 4688 board designers haven't used it for something that would 4689 cause you grief during the initial boot! It is frequently not 4690 used. 4691 4692 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4693 with your processor/board/system design. The default value 4694 you will find in any recent u-boot distribution in 4695 walnut.h should work for you. I'd set it to a value larger 4696 than your SDRAM module. If you have a 64MB SDRAM module, set 4697 it above 400_0000. Just make sure your board has no resources 4698 that are supposed to respond to that address! That code in 4699 start.S has been around a while and should work as is when 4700 you get the config right. 4701 4702 -Chris Hallinan 4703 DS4.COM, Inc. 4704 4705It is essential to remember this, since it has some impact on the C 4706code for the initialization procedures: 4707 4708* Initialized global data (data segment) is read-only. Do not attempt 4709 to write it. 4710 4711* Do not use any uninitialized global data (or implicitly initialized 4712 as zero data - BSS segment) at all - this is undefined, initiali- 4713 zation is performed later (when relocating to RAM). 4714 4715* Stack space is very limited. Avoid big data buffers or things like 4716 that. 4717 4718Having only the stack as writable memory limits means we cannot use 4719normal global data to share information between the code. But it 4720turned out that the implementation of U-Boot can be greatly 4721simplified by making a global data structure (gd_t) available to all 4722functions. We could pass a pointer to this data as argument to _all_ 4723functions, but this would bloat the code. Instead we use a feature of 4724the GCC compiler (Global Register Variables) to share the data: we 4725place a pointer (gd) to the global data into a register which we 4726reserve for this purpose. 4727 4728When choosing a register for such a purpose we are restricted by the 4729relevant (E)ABI specifications for the current architecture, and by 4730GCC's implementation. 4731 4732For PowerPC, the following registers have specific use: 4733 R1: stack pointer 4734 R2: reserved for system use 4735 R3-R4: parameter passing and return values 4736 R5-R10: parameter passing 4737 R13: small data area pointer 4738 R30: GOT pointer 4739 R31: frame pointer 4740 4741 (U-Boot also uses R12 as internal GOT pointer. r12 4742 is a volatile register so r12 needs to be reset when 4743 going back and forth between asm and C) 4744 4745 ==> U-Boot will use R2 to hold a pointer to the global data 4746 4747 Note: on PPC, we could use a static initializer (since the 4748 address of the global data structure is known at compile time), 4749 but it turned out that reserving a register results in somewhat 4750 smaller code - although the code savings are not that big (on 4751 average for all boards 752 bytes for the whole U-Boot image, 4752 624 text + 127 data). 4753 4754On ARM, the following registers are used: 4755 4756 R0: function argument word/integer result 4757 R1-R3: function argument word 4758 R9: platform specific 4759 R10: stack limit (used only if stack checking is enabled) 4760 R11: argument (frame) pointer 4761 R12: temporary workspace 4762 R13: stack pointer 4763 R14: link register 4764 R15: program counter 4765 4766 ==> U-Boot will use R9 to hold a pointer to the global data 4767 4768 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4769 4770On Nios II, the ABI is documented here: 4771 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4772 4773 ==> U-Boot will use gp to hold a pointer to the global data 4774 4775 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4776 to access small data sections, so gp is free. 4777 4778On NDS32, the following registers are used: 4779 4780 R0-R1: argument/return 4781 R2-R5: argument 4782 R15: temporary register for assembler 4783 R16: trampoline register 4784 R28: frame pointer (FP) 4785 R29: global pointer (GP) 4786 R30: link register (LP) 4787 R31: stack pointer (SP) 4788 PC: program counter (PC) 4789 4790 ==> U-Boot will use R10 to hold a pointer to the global data 4791 4792NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4793or current versions of GCC may "optimize" the code too much. 4794 4795On RISC-V, the following registers are used: 4796 4797 x0: hard-wired zero (zero) 4798 x1: return address (ra) 4799 x2: stack pointer (sp) 4800 x3: global pointer (gp) 4801 x4: thread pointer (tp) 4802 x5: link register (t0) 4803 x8: frame pointer (fp) 4804 x10-x11: arguments/return values (a0-1) 4805 x12-x17: arguments (a2-7) 4806 x28-31: temporaries (t3-6) 4807 pc: program counter (pc) 4808 4809 ==> U-Boot will use gp to hold a pointer to the global data 4810 4811Memory Management: 4812------------------ 4813 4814U-Boot runs in system state and uses physical addresses, i.e. the 4815MMU is not used either for address mapping nor for memory protection. 4816 4817The available memory is mapped to fixed addresses using the memory 4818controller. In this process, a contiguous block is formed for each 4819memory type (Flash, SDRAM, SRAM), even when it consists of several 4820physical memory banks. 4821 4822U-Boot is installed in the first 128 kB of the first Flash bank (on 4823TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4824booting and sizing and initializing DRAM, the code relocates itself 4825to the upper end of DRAM. Immediately below the U-Boot code some 4826memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4827configuration setting]. Below that, a structure with global Board 4828Info data is placed, followed by the stack (growing downward). 4829 4830Additionally, some exception handler code is copied to the low 8 kB 4831of DRAM (0x00000000 ... 0x00001FFF). 4832 4833So a typical memory configuration with 16 MB of DRAM could look like 4834this: 4835 4836 0x0000 0000 Exception Vector code 4837 : 4838 0x0000 1FFF 4839 0x0000 2000 Free for Application Use 4840 : 4841 : 4842 4843 : 4844 : 4845 0x00FB FF20 Monitor Stack (Growing downward) 4846 0x00FB FFAC Board Info Data and permanent copy of global data 4847 0x00FC 0000 Malloc Arena 4848 : 4849 0x00FD FFFF 4850 0x00FE 0000 RAM Copy of Monitor Code 4851 ... eventually: LCD or video framebuffer 4852 ... eventually: pRAM (Protected RAM - unchanged by reset) 4853 0x00FF FFFF [End of RAM] 4854 4855 4856System Initialization: 4857---------------------- 4858 4859In the reset configuration, U-Boot starts at the reset entry point 4860(on most PowerPC systems at address 0x00000100). Because of the reset 4861configuration for CS0# this is a mirror of the on board Flash memory. 4862To be able to re-map memory U-Boot then jumps to its link address. 4863To be able to implement the initialization code in C, a (small!) 4864initial stack is set up in the internal Dual Ported RAM (in case CPUs 4865which provide such a feature like), or in a locked part of the data 4866cache. After that, U-Boot initializes the CPU core, the caches and 4867the SIU. 4868 4869Next, all (potentially) available memory banks are mapped using a 4870preliminary mapping. For example, we put them on 512 MB boundaries 4871(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4872on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4873programmed for SDRAM access. Using the temporary configuration, a 4874simple memory test is run that determines the size of the SDRAM 4875banks. 4876 4877When there is more than one SDRAM bank, and the banks are of 4878different size, the largest is mapped first. For equal size, the first 4879bank (CS2#) is mapped first. The first mapping is always for address 48800x00000000, with any additional banks following immediately to create 4881contiguous memory starting from 0. 4882 4883Then, the monitor installs itself at the upper end of the SDRAM area 4884and allocates memory for use by malloc() and for the global Board 4885Info data; also, the exception vector code is copied to the low RAM 4886pages, and the final stack is set up. 4887 4888Only after this relocation will you have a "normal" C environment; 4889until that you are restricted in several ways, mostly because you are 4890running from ROM, and because the code will have to be relocated to a 4891new address in RAM. 4892 4893 4894U-Boot Porting Guide: 4895---------------------- 4896 4897[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4898list, October 2002] 4899 4900 4901int main(int argc, char *argv[]) 4902{ 4903 sighandler_t no_more_time; 4904 4905 signal(SIGALRM, no_more_time); 4906 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4907 4908 if (available_money > available_manpower) { 4909 Pay consultant to port U-Boot; 4910 return 0; 4911 } 4912 4913 Download latest U-Boot source; 4914 4915 Subscribe to u-boot mailing list; 4916 4917 if (clueless) 4918 email("Hi, I am new to U-Boot, how do I get started?"); 4919 4920 while (learning) { 4921 Read the README file in the top level directory; 4922 Read http://www.denx.de/twiki/bin/view/DULG/Manual; 4923 Read applicable doc/*.README; 4924 Read the source, Luke; 4925 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4926 } 4927 4928 if (available_money > toLocalCurrency ($2500)) 4929 Buy a BDI3000; 4930 else 4931 Add a lot of aggravation and time; 4932 4933 if (a similar board exists) { /* hopefully... */ 4934 cp -a board/<similar> board/<myboard> 4935 cp include/configs/<similar>.h include/configs/<myboard>.h 4936 } else { 4937 Create your own board support subdirectory; 4938 Create your own board include/configs/<myboard>.h file; 4939 } 4940 Edit new board/<myboard> files 4941 Edit new include/configs/<myboard>.h 4942 4943 while (!accepted) { 4944 while (!running) { 4945 do { 4946 Add / modify source code; 4947 } until (compiles); 4948 Debug; 4949 if (clueless) 4950 email("Hi, I am having problems..."); 4951 } 4952 Send patch file to the U-Boot email list; 4953 if (reasonable critiques) 4954 Incorporate improvements from email list code review; 4955 else 4956 Defend code as written; 4957 } 4958 4959 return 0; 4960} 4961 4962void no_more_time (int sig) 4963{ 4964 hire_a_guru(); 4965} 4966 4967 4968Coding Standards: 4969----------------- 4970 4971All contributions to U-Boot should conform to the Linux kernel 4972coding style; see the kernel coding style guide at 4973https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4974script "scripts/Lindent" in your Linux kernel source directory. 4975 4976Source files originating from a different project (for example the 4977MTD subsystem) are generally exempt from these guidelines and are not 4978reformatted to ease subsequent migration to newer versions of those 4979sources. 4980 4981Please note that U-Boot is implemented in C (and to some small parts in 4982Assembler); no C++ is used, so please do not use C++ style comments (//) 4983in your code. 4984 4985Please also stick to the following formatting rules: 4986- remove any trailing white space 4987- use TAB characters for indentation and vertical alignment, not spaces 4988- make sure NOT to use DOS '\r\n' line feeds 4989- do not add more than 2 consecutive empty lines to source files 4990- do not add trailing empty lines to source files 4991 4992Submissions which do not conform to the standards may be returned 4993with a request to reformat the changes. 4994 4995 4996Submitting Patches: 4997------------------- 4998 4999Since the number of patches for U-Boot is growing, we need to 5000establish some rules. Submissions which do not conform to these rules 5001may be rejected, even when they contain important and valuable stuff. 5002 5003Please see http://www.denx.de/wiki/U-Boot/Patches for details. 5004 5005Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 5006see https://lists.denx.de/listinfo/u-boot 5007 5008When you send a patch, please include the following information with 5009it: 5010 5011* For bug fixes: a description of the bug and how your patch fixes 5012 this bug. Please try to include a way of demonstrating that the 5013 patch actually fixes something. 5014 5015* For new features: a description of the feature and your 5016 implementation. 5017 5018* A CHANGELOG entry as plaintext (separate from the patch) 5019 5020* For major contributions, add a MAINTAINERS file with your 5021 information and associated file and directory references. 5022 5023* When you add support for a new board, don't forget to add a 5024 maintainer e-mail address to the boards.cfg file, too. 5025 5026* If your patch adds new configuration options, don't forget to 5027 document these in the README file. 5028 5029* The patch itself. If you are using git (which is *strongly* 5030 recommended) you can easily generate the patch using the 5031 "git format-patch". If you then use "git send-email" to send it to 5032 the U-Boot mailing list, you will avoid most of the common problems 5033 with some other mail clients. 5034 5035 If you cannot use git, use "diff -purN OLD NEW". If your version of 5036 diff does not support these options, then get the latest version of 5037 GNU diff. 5038 5039 The current directory when running this command shall be the parent 5040 directory of the U-Boot source tree (i. e. please make sure that 5041 your patch includes sufficient directory information for the 5042 affected files). 5043 5044 We prefer patches as plain text. MIME attachments are discouraged, 5045 and compressed attachments must not be used. 5046 5047* If one logical set of modifications affects or creates several 5048 files, all these changes shall be submitted in a SINGLE patch file. 5049 5050* Changesets that contain different, unrelated modifications shall be 5051 submitted as SEPARATE patches, one patch per changeset. 5052 5053 5054Notes: 5055 5056* Before sending the patch, run the buildman script on your patched 5057 source tree and make sure that no errors or warnings are reported 5058 for any of the boards. 5059 5060* Keep your modifications to the necessary minimum: A patch 5061 containing several unrelated changes or arbitrary reformats will be 5062 returned with a request to re-formatting / split it. 5063 5064* If you modify existing code, make sure that your new code does not 5065 add to the memory footprint of the code ;-) Small is beautiful! 5066 When adding new features, these should compile conditionally only 5067 (using #ifdef), and the resulting code with the new feature 5068 disabled must not need more memory than the old code without your 5069 modification. 5070 5071* Remember that there is a size limit of 100 kB per message on the 5072 u-boot mailing list. Bigger patches will be moderated. If they are 5073 reasonable and not too big, they will be acknowledged. But patches 5074 bigger than the size limit should be avoided. 5075