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_XWAY_SWAP_BYTES 532 533 Enable compilation of tools/xway-swap-bytes needed for Lantiq 534 XWAY SoCs for booting from NOR flash. The U-Boot image needs to 535 be swapped if a flash programmer is used. 536 537- ARM options: 538 CONFIG_SYS_EXCEPTION_VECTORS_HIGH 539 540 Select high exception vectors of the ARM core, e.g., do not 541 clear the V bit of the c1 register of CP15. 542 543 COUNTER_FREQUENCY 544 Generic timer clock source frequency. 545 546 COUNTER_FREQUENCY_REAL 547 Generic timer clock source frequency if the real clock is 548 different from COUNTER_FREQUENCY, and can only be determined 549 at run time. 550 551- Tegra SoC options: 552 CONFIG_TEGRA_SUPPORT_NON_SECURE 553 554 Support executing U-Boot in non-secure (NS) mode. Certain 555 impossible actions will be skipped if the CPU is in NS mode, 556 such as ARM architectural timer initialization. 557 558- Linux Kernel Interface: 559 CONFIG_CLOCKS_IN_MHZ 560 561 U-Boot stores all clock information in Hz 562 internally. For binary compatibility with older Linux 563 kernels (which expect the clocks passed in the 564 bd_info data to be in MHz) the environment variable 565 "clocks_in_mhz" can be defined so that U-Boot 566 converts clock data to MHZ before passing it to the 567 Linux kernel. 568 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 569 "clocks_in_mhz=1" is automatically included in the 570 default environment. 571 572 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 573 574 When transferring memsize parameter to Linux, some versions 575 expect it to be in bytes, others in MB. 576 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 577 578 CONFIG_OF_LIBFDT 579 580 New kernel versions are expecting firmware settings to be 581 passed using flattened device trees (based on open firmware 582 concepts). 583 584 CONFIG_OF_LIBFDT 585 * New libfdt-based support 586 * Adds the "fdt" command 587 * The bootm command automatically updates the fdt 588 589 OF_TBCLK - The timebase frequency. 590 OF_STDOUT_PATH - The path to the console device 591 592 boards with QUICC Engines require OF_QE to set UCC MAC 593 addresses 594 595 CONFIG_OF_BOARD_SETUP 596 597 Board code has addition modification that it wants to make 598 to the flat device tree before handing it off to the kernel 599 600 CONFIG_OF_SYSTEM_SETUP 601 602 Other code has addition modification that it wants to make 603 to the flat device tree before handing it off to the kernel. 604 This causes ft_system_setup() to be called before booting 605 the kernel. 606 607 CONFIG_OF_IDE_FIXUP 608 609 U-Boot can detect if an IDE device is present or not. 610 If not, and this new config option is activated, U-Boot 611 removes the ATA node from the DTS before booting Linux, 612 so the Linux IDE driver does not probe the device and 613 crash. This is needed for buggy hardware (uc101) where 614 no pull down resistor is connected to the signal IDE5V_DD7. 615 616 CONFIG_MACH_TYPE [relevant for ARM only][mandatory] 617 618 This setting is mandatory for all boards that have only one 619 machine type and must be used to specify the machine type 620 number as it appears in the ARM machine registry 621 (see http://www.arm.linux.org.uk/developer/machines/). 622 Only boards that have multiple machine types supported 623 in a single configuration file and the machine type is 624 runtime discoverable, do not have to use this setting. 625 626- vxWorks boot parameters: 627 628 bootvx constructs a valid bootline using the following 629 environments variables: bootdev, bootfile, ipaddr, netmask, 630 serverip, gatewayip, hostname, othbootargs. 631 It loads the vxWorks image pointed bootfile. 632 633 Note: If a "bootargs" environment is defined, it will overwride 634 the defaults discussed just above. 635 636- Cache Configuration: 637 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot 638 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot 639 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot 640 641- Cache Configuration for ARM: 642 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache 643 controller 644 CONFIG_SYS_PL310_BASE - Physical base address of PL310 645 controller register space 646 647- Serial Ports: 648 CONFIG_PL010_SERIAL 649 650 Define this if you want support for Amba PrimeCell PL010 UARTs. 651 652 CONFIG_PL011_SERIAL 653 654 Define this if you want support for Amba PrimeCell PL011 UARTs. 655 656 CONFIG_PL011_CLOCK 657 658 If you have Amba PrimeCell PL011 UARTs, set this variable to 659 the clock speed of the UARTs. 660 661 CONFIG_PL01x_PORTS 662 663 If you have Amba PrimeCell PL010 or PL011 UARTs on your board, 664 define this to a list of base addresses for each (supported) 665 port. See e.g. include/configs/versatile.h 666 667 CONFIG_SERIAL_HW_FLOW_CONTROL 668 669 Define this variable to enable hw flow control in serial driver. 670 Current user of this option is drivers/serial/nsl16550.c driver 671 672- Console Baudrate: 673 CONFIG_BAUDRATE - in bps 674 Select one of the baudrates listed in 675 CONFIG_SYS_BAUDRATE_TABLE, see below. 676 677- Autoboot Command: 678 CONFIG_BOOTCOMMAND 679 Only needed when CONFIG_BOOTDELAY is enabled; 680 define a command string that is automatically executed 681 when no character is read on the console interface 682 within "Boot Delay" after reset. 683 684 CONFIG_RAMBOOT and CONFIG_NFSBOOT 685 The value of these goes into the environment as 686 "ramboot" and "nfsboot" respectively, and can be used 687 as a convenience, when switching between booting from 688 RAM and NFS. 689 690- Pre-Boot Commands: 691 CONFIG_PREBOOT 692 693 When this option is #defined, the existence of the 694 environment variable "preboot" will be checked 695 immediately before starting the CONFIG_BOOTDELAY 696 countdown and/or running the auto-boot command resp. 697 entering interactive mode. 698 699 This feature is especially useful when "preboot" is 700 automatically generated or modified. For an example 701 see the LWMON board specific code: here "preboot" is 702 modified when the user holds down a certain 703 combination of keys on the (special) keyboard when 704 booting the systems 705 706- Serial Download Echo Mode: 707 CONFIG_LOADS_ECHO 708 If defined to 1, all characters received during a 709 serial download (using the "loads" command) are 710 echoed back. This might be needed by some terminal 711 emulations (like "cu"), but may as well just take 712 time on others. This setting #define's the initial 713 value of the "loads_echo" environment variable. 714 715- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined) 716 CONFIG_KGDB_BAUDRATE 717 Select one of the baudrates listed in 718 CONFIG_SYS_BAUDRATE_TABLE, see below. 719 720- Removal of commands 721 If no commands are needed to boot, you can disable 722 CONFIG_CMDLINE to remove them. In this case, the command line 723 will not be available, and when U-Boot wants to execute the 724 boot command (on start-up) it will call board_run_command() 725 instead. This can reduce image size significantly for very 726 simple boot procedures. 727 728- Regular expression support: 729 CONFIG_REGEX 730 If this variable is defined, U-Boot is linked against 731 the SLRE (Super Light Regular Expression) library, 732 which adds regex support to some commands, as for 733 example "env grep" and "setexpr". 734 735- Device tree: 736 CONFIG_OF_CONTROL 737 If this variable is defined, U-Boot will use a device tree 738 to configure its devices, instead of relying on statically 739 compiled #defines in the board file. This option is 740 experimental and only available on a few boards. The device 741 tree is available in the global data as gd->fdt_blob. 742 743 U-Boot needs to get its device tree from somewhere. This can 744 be done using one of the three options below: 745 746 CONFIG_OF_EMBED 747 If this variable is defined, U-Boot will embed a device tree 748 binary in its image. This device tree file should be in the 749 board directory and called <soc>-<board>.dts. The binary file 750 is then picked up in board_init_f() and made available through 751 the global data structure as gd->fdt_blob. 752 753 CONFIG_OF_SEPARATE 754 If this variable is defined, U-Boot will build a device tree 755 binary. It will be called u-boot.dtb. Architecture-specific 756 code will locate it at run-time. Generally this works by: 757 758 cat u-boot.bin u-boot.dtb >image.bin 759 760 and in fact, U-Boot does this for you, creating a file called 761 u-boot-dtb.bin which is useful in the common case. You can 762 still use the individual files if you need something more 763 exotic. 764 765 CONFIG_OF_BOARD 766 If this variable is defined, U-Boot will use the device tree 767 provided by the board at runtime instead of embedding one with 768 the image. Only boards defining board_fdt_blob_setup() support 769 this option (see include/fdtdec.h file). 770 771- Watchdog: 772 CONFIG_WATCHDOG 773 If this variable is defined, it enables watchdog 774 support for the SoC. There must be support in the SoC 775 specific code for a watchdog. For the 8xx 776 CPUs, the SIU Watchdog feature is enabled in the SYPCR 777 register. When supported for a specific SoC is 778 available, then no further board specific code should 779 be needed to use it. 780 781 CONFIG_HW_WATCHDOG 782 When using a watchdog circuitry external to the used 783 SoC, then define this variable and provide board 784 specific code for the "hw_watchdog_reset" function. 785 786 CONFIG_AT91_HW_WDT_TIMEOUT 787 specify the timeout in seconds. default 2 seconds. 788 789- Real-Time Clock: 790 791 When CONFIG_CMD_DATE is selected, the type of the RTC 792 has to be selected, too. Define exactly one of the 793 following options: 794 795 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 796 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC 797 CONFIG_RTC_MC146818 - use MC146818 RTC 798 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 799 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 800 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 801 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC 802 CONFIG_RTC_DS164x - use Dallas DS164x RTC 803 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC 804 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 805 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337 806 CONFIG_SYS_RV3029_TCR - enable trickle charger on 807 RV3029 RTC. 808 809 Note that if the RTC uses I2C, then the I2C interface 810 must also be configured. See I2C Support, below. 811 812- GPIO Support: 813 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO 814 815 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of 816 chip-ngpio pairs that tell the PCA953X driver the number of 817 pins supported by a particular chip. 818 819 Note that if the GPIO device uses I2C, then the I2C interface 820 must also be configured. See I2C Support, below. 821 822- I/O tracing: 823 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O 824 accesses and can checksum them or write a list of them out 825 to memory. See the 'iotrace' command for details. This is 826 useful for testing device drivers since it can confirm that 827 the driver behaves the same way before and after a code 828 change. Currently this is supported on sandbox and arm. To 829 add support for your architecture, add '#include <iotrace.h>' 830 to the bottom of arch/<arch>/include/asm/io.h and test. 831 832 Example output from the 'iotrace stats' command is below. 833 Note that if the trace buffer is exhausted, the checksum will 834 still continue to operate. 835 836 iotrace is enabled 837 Start: 10000000 (buffer start address) 838 Size: 00010000 (buffer size) 839 Offset: 00000120 (current buffer offset) 840 Output: 10000120 (start + offset) 841 Count: 00000018 (number of trace records) 842 CRC32: 9526fb66 (CRC32 of all trace records) 843 844- Timestamp Support: 845 846 When CONFIG_TIMESTAMP is selected, the timestamp 847 (date and time) of an image is printed by image 848 commands like bootm or iminfo. This option is 849 automatically enabled when you select CONFIG_CMD_DATE . 850 851- Partition Labels (disklabels) Supported: 852 Zero or more of the following: 853 CONFIG_MAC_PARTITION Apple's MacOS partition table. 854 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc. 855 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the 856 bootloader. Note 2TB partition limit; see 857 disk/part_efi.c 858 CONFIG_SCSI) you must configure support for at 859 least one non-MTD partition type as well. 860 861- IDE Reset method: 862 CONFIG_IDE_RESET_ROUTINE - this is defined in several 863 board configurations files but used nowhere! 864 865 CONFIG_IDE_RESET - is this is defined, IDE Reset will 866 be performed by calling the function 867 ide_set_reset(int reset) 868 which has to be defined in a board specific file 869 870- ATAPI Support: 871 CONFIG_ATAPI 872 873 Set this to enable ATAPI support. 874 875- LBA48 Support 876 CONFIG_LBA48 877 878 Set this to enable support for disks larger than 137GB 879 Also look at CONFIG_SYS_64BIT_LBA. 880 Whithout these , LBA48 support uses 32bit variables and will 'only' 881 support disks up to 2.1TB. 882 883 CONFIG_SYS_64BIT_LBA: 884 When enabled, makes the IDE subsystem use 64bit sector addresses. 885 Default is 32bit. 886 887- SCSI Support: 888 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and 889 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID * 890 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the 891 maximum numbers of LUNs, SCSI ID's and target 892 devices. 893 894 The environment variable 'scsidevs' is set to the number of 895 SCSI devices found during the last scan. 896 897- NETWORK Support (PCI): 898 CONFIG_E1000 899 Support for Intel 8254x/8257x gigabit chips. 900 901 CONFIG_E1000_SPI 902 Utility code for direct access to the SPI bus on Intel 8257x. 903 This does not do anything useful unless you set at least one 904 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC. 905 906 CONFIG_E1000_SPI_GENERIC 907 Allow generic access to the SPI bus on the Intel 8257x, for 908 example with the "sspi" command. 909 910 CONFIG_EEPRO100 911 Support for Intel 82557/82559/82559ER chips. 912 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM 913 write routine for first time initialisation. 914 915 CONFIG_TULIP 916 Support for Digital 2114x chips. 917 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 918 modem chip initialisation (KS8761/QS6611). 919 920 CONFIG_NATSEMI 921 Support for National dp83815 chips. 922 923 CONFIG_NS8382X 924 Support for National dp8382[01] gigabit chips. 925 926- NETWORK Support (other): 927 928 CONFIG_DRIVER_AT91EMAC 929 Support for AT91RM9200 EMAC. 930 931 CONFIG_RMII 932 Define this to use reduced MII inteface 933 934 CONFIG_DRIVER_AT91EMAC_QUIET 935 If this defined, the driver is quiet. 936 The driver doen't show link status messages. 937 938 CONFIG_CALXEDA_XGMAC 939 Support for the Calxeda XGMAC device 940 941 CONFIG_LAN91C96 942 Support for SMSC's LAN91C96 chips. 943 944 CONFIG_LAN91C96_USE_32_BIT 945 Define this to enable 32 bit addressing 946 947 CONFIG_SMC91111 948 Support for SMSC's LAN91C111 chip 949 950 CONFIG_SMC91111_BASE 951 Define this to hold the physical address 952 of the device (I/O space) 953 954 CONFIG_SMC_USE_32_BIT 955 Define this if data bus is 32 bits 956 957 CONFIG_SMC_USE_IOFUNCS 958 Define this to use i/o functions instead of macros 959 (some hardware wont work with macros) 960 961 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 962 Define this if you have more then 3 PHYs. 963 964 CONFIG_FTGMAC100 965 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 966 967 CONFIG_FTGMAC100_EGIGA 968 Define this to use GE link update with gigabit PHY. 969 Define this if FTGMAC100 is connected to gigabit PHY. 970 If your system has 10/100 PHY only, it might not occur 971 wrong behavior. Because PHY usually return timeout or 972 useless data when polling gigabit status and gigabit 973 control registers. This behavior won't affect the 974 correctnessof 10/100 link speed update. 975 976 CONFIG_SH_ETHER 977 Support for Renesas on-chip Ethernet controller 978 979 CONFIG_SH_ETHER_USE_PORT 980 Define the number of ports to be used 981 982 CONFIG_SH_ETHER_PHY_ADDR 983 Define the ETH PHY's address 984 985 CONFIG_SH_ETHER_CACHE_WRITEBACK 986 If this option is set, the driver enables cache flush. 987 988- PWM Support: 989 CONFIG_PWM_IMX 990 Support for PWM module on the imx6. 991 992- TPM Support: 993 CONFIG_TPM 994 Support TPM devices. 995 996 CONFIG_TPM_TIS_INFINEON 997 Support for Infineon i2c bus TPM devices. Only one device 998 per system is supported at this time. 999 1000 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 1001 Define the burst count bytes upper limit 1002 1003 CONFIG_TPM_ST33ZP24 1004 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 1005 1006 CONFIG_TPM_ST33ZP24_I2C 1007 Support for STMicroelectronics ST33ZP24 I2C devices. 1008 Requires TPM_ST33ZP24 and I2C. 1009 1010 CONFIG_TPM_ST33ZP24_SPI 1011 Support for STMicroelectronics ST33ZP24 SPI devices. 1012 Requires TPM_ST33ZP24 and SPI. 1013 1014 CONFIG_TPM_ATMEL_TWI 1015 Support for Atmel TWI TPM device. Requires I2C support. 1016 1017 CONFIG_TPM_TIS_LPC 1018 Support for generic parallel port TPM devices. Only one device 1019 per system is supported at this time. 1020 1021 CONFIG_TPM_TIS_BASE_ADDRESS 1022 Base address where the generic TPM device is mapped 1023 to. Contemporary x86 systems usually map it at 1024 0xfed40000. 1025 1026 CONFIG_TPM 1027 Define this to enable the TPM support library which provides 1028 functional interfaces to some TPM commands. 1029 Requires support for a TPM device. 1030 1031 CONFIG_TPM_AUTH_SESSIONS 1032 Define this to enable authorized functions in the TPM library. 1033 Requires CONFIG_TPM and CONFIG_SHA1. 1034 1035- USB Support: 1036 At the moment only the UHCI host controller is 1037 supported (PIP405, MIP405); define 1038 CONFIG_USB_UHCI to enable it. 1039 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 1040 and define CONFIG_USB_STORAGE to enable the USB 1041 storage devices. 1042 Note: 1043 Supported are USB Keyboards and USB Floppy drives 1044 (TEAC FD-05PUB). 1045 1046 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 1047 txfilltuning field in the EHCI controller on reset. 1048 1049 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2 1050 HW module registers. 1051 1052- USB Device: 1053 Define the below if you wish to use the USB console. 1054 Once firmware is rebuilt from a serial console issue the 1055 command "setenv stdin usbtty; setenv stdout usbtty" and 1056 attach your USB cable. The Unix command "dmesg" should print 1057 it has found a new device. The environment variable usbtty 1058 can be set to gserial or cdc_acm to enable your device to 1059 appear to a USB host as a Linux gserial device or a 1060 Common Device Class Abstract Control Model serial device. 1061 If you select usbtty = gserial you should be able to enumerate 1062 a Linux host by 1063 # modprobe usbserial vendor=0xVendorID product=0xProductID 1064 else if using cdc_acm, simply setting the environment 1065 variable usbtty to be cdc_acm should suffice. The following 1066 might be defined in YourBoardName.h 1067 1068 CONFIG_USB_DEVICE 1069 Define this to build a UDC device 1070 1071 CONFIG_USB_TTY 1072 Define this to have a tty type of device available to 1073 talk to the UDC device 1074 1075 CONFIG_USBD_HS 1076 Define this to enable the high speed support for usb 1077 device and usbtty. If this feature is enabled, a routine 1078 int is_usbd_high_speed(void) 1079 also needs to be defined by the driver to dynamically poll 1080 whether the enumeration has succeded at high speed or full 1081 speed. 1082 1083 CONFIG_SYS_CONSOLE_IS_IN_ENV 1084 Define this if you want stdin, stdout &/or stderr to 1085 be set to usbtty. 1086 1087 If you have a USB-IF assigned VendorID then you may wish to 1088 define your own vendor specific values either in BoardName.h 1089 or directly in usbd_vendor_info.h. If you don't define 1090 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 1091 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 1092 should pretend to be a Linux device to it's target host. 1093 1094 CONFIG_USBD_MANUFACTURER 1095 Define this string as the name of your company for 1096 - CONFIG_USBD_MANUFACTURER "my company" 1097 1098 CONFIG_USBD_PRODUCT_NAME 1099 Define this string as the name of your product 1100 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 1101 1102 CONFIG_USBD_VENDORID 1103 Define this as your assigned Vendor ID from the USB 1104 Implementors Forum. This *must* be a genuine Vendor ID 1105 to avoid polluting the USB namespace. 1106 - CONFIG_USBD_VENDORID 0xFFFF 1107 1108 CONFIG_USBD_PRODUCTID 1109 Define this as the unique Product ID 1110 for your device 1111 - CONFIG_USBD_PRODUCTID 0xFFFF 1112 1113- ULPI Layer Support: 1114 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 1115 the generic ULPI layer. The generic layer accesses the ULPI PHY 1116 via the platform viewport, so you need both the genric layer and 1117 the viewport enabled. Currently only Chipidea/ARC based 1118 viewport is supported. 1119 To enable the ULPI layer support, define CONFIG_USB_ULPI and 1120 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 1121 If your ULPI phy needs a different reference clock than the 1122 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 1123 the appropriate value in Hz. 1124 1125- MMC Support: 1126 The MMC controller on the Intel PXA is supported. To 1127 enable this define CONFIG_MMC. The MMC can be 1128 accessed from the boot prompt by mapping the device 1129 to physical memory similar to flash. Command line is 1130 enabled with CONFIG_CMD_MMC. The MMC driver also works with 1131 the FAT fs. This is enabled with CONFIG_CMD_FAT. 1132 1133 CONFIG_SH_MMCIF 1134 Support for Renesas on-chip MMCIF controller 1135 1136 CONFIG_SH_MMCIF_ADDR 1137 Define the base address of MMCIF registers 1138 1139 CONFIG_SH_MMCIF_CLK 1140 Define the clock frequency for MMCIF 1141 1142 CONFIG_SUPPORT_EMMC_BOOT 1143 Enable some additional features of the eMMC boot partitions. 1144 1145- USB Device Firmware Update (DFU) class support: 1146 CONFIG_DFU_OVER_USB 1147 This enables the USB portion of the DFU USB class 1148 1149 CONFIG_DFU_MMC 1150 This enables support for exposing (e)MMC devices via DFU. 1151 1152 CONFIG_DFU_NAND 1153 This enables support for exposing NAND devices via DFU. 1154 1155 CONFIG_DFU_RAM 1156 This enables support for exposing RAM via DFU. 1157 Note: DFU spec refer to non-volatile memory usage, but 1158 allow usages beyond the scope of spec - here RAM usage, 1159 one that would help mostly the developer. 1160 1161 CONFIG_SYS_DFU_DATA_BUF_SIZE 1162 Dfu transfer uses a buffer before writing data to the 1163 raw storage device. Make the size (in bytes) of this buffer 1164 configurable. The size of this buffer is also configurable 1165 through the "dfu_bufsiz" environment variable. 1166 1167 CONFIG_SYS_DFU_MAX_FILE_SIZE 1168 When updating files rather than the raw storage device, 1169 we use a static buffer to copy the file into and then write 1170 the buffer once we've been given the whole file. Define 1171 this to the maximum filesize (in bytes) for the buffer. 1172 Default is 4 MiB if undefined. 1173 1174 DFU_DEFAULT_POLL_TIMEOUT 1175 Poll timeout [ms], is the timeout a device can send to the 1176 host. The host must wait for this timeout before sending 1177 a subsequent DFU_GET_STATUS request to the device. 1178 1179 DFU_MANIFEST_POLL_TIMEOUT 1180 Poll timeout [ms], which the device sends to the host when 1181 entering dfuMANIFEST state. Host waits this timeout, before 1182 sending again an USB request to the device. 1183 1184- Journaling Flash filesystem support: 1185 CONFIG_JFFS2_NAND 1186 Define these for a default partition on a NAND device 1187 1188 CONFIG_SYS_JFFS2_FIRST_SECTOR, 1189 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 1190 Define these for a default partition on a NOR device 1191 1192- Keyboard Support: 1193 See Kconfig help for available keyboard drivers. 1194 1195 CONFIG_KEYBOARD 1196 1197 Define this to enable a custom keyboard support. 1198 This simply calls drv_keyboard_init() which must be 1199 defined in your board-specific files. This option is deprecated 1200 and is only used by novena. For new boards, use driver model 1201 instead. 1202 1203- Video support: 1204 CONFIG_FSL_DIU_FB 1205 Enable the Freescale DIU video driver. Reference boards for 1206 SOCs that have a DIU should define this macro to enable DIU 1207 support, and should also define these other macros: 1208 1209 CONFIG_SYS_DIU_ADDR 1210 CONFIG_VIDEO 1211 CONFIG_CFB_CONSOLE 1212 CONFIG_VIDEO_SW_CURSOR 1213 CONFIG_VGA_AS_SINGLE_DEVICE 1214 CONFIG_VIDEO_LOGO 1215 CONFIG_VIDEO_BMP_LOGO 1216 1217 The DIU driver will look for the 'video-mode' environment 1218 variable, and if defined, enable the DIU as a console during 1219 boot. See the documentation file doc/README.video for a 1220 description of this variable. 1221 1222- LCD Support: CONFIG_LCD 1223 1224 Define this to enable LCD support (for output to LCD 1225 display); also select one of the supported displays 1226 by defining one of these: 1227 1228 CONFIG_ATMEL_LCD: 1229 1230 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1231 1232 CONFIG_NEC_NL6448AC33: 1233 1234 NEC NL6448AC33-18. Active, color, single scan. 1235 1236 CONFIG_NEC_NL6448BC20 1237 1238 NEC NL6448BC20-08. 6.5", 640x480. 1239 Active, color, single scan. 1240 1241 CONFIG_NEC_NL6448BC33_54 1242 1243 NEC NL6448BC33-54. 10.4", 640x480. 1244 Active, color, single scan. 1245 1246 CONFIG_SHARP_16x9 1247 1248 Sharp 320x240. Active, color, single scan. 1249 It isn't 16x9, and I am not sure what it is. 1250 1251 CONFIG_SHARP_LQ64D341 1252 1253 Sharp LQ64D341 display, 640x480. 1254 Active, color, single scan. 1255 1256 CONFIG_HLD1045 1257 1258 HLD1045 display, 640x480. 1259 Active, color, single scan. 1260 1261 CONFIG_OPTREX_BW 1262 1263 Optrex CBL50840-2 NF-FW 99 22 M5 1264 or 1265 Hitachi LMG6912RPFC-00T 1266 or 1267 Hitachi SP14Q002 1268 1269 320x240. Black & white. 1270 1271 CONFIG_LCD_ALIGNMENT 1272 1273 Normally the LCD is page-aligned (typically 4KB). If this is 1274 defined then the LCD will be aligned to this value instead. 1275 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1276 here, since it is cheaper to change data cache settings on 1277 a per-section basis. 1278 1279 1280 CONFIG_LCD_ROTATION 1281 1282 Sometimes, for example if the display is mounted in portrait 1283 mode or even if it's mounted landscape but rotated by 180degree, 1284 we need to rotate our content of the display relative to the 1285 framebuffer, so that user can read the messages which are 1286 printed out. 1287 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1288 initialized with a given rotation from "vl_rot" out of 1289 "vidinfo_t" which is provided by the board specific code. 1290 The value for vl_rot is coded as following (matching to 1291 fbcon=rotate:<n> linux-kernel commandline): 1292 0 = no rotation respectively 0 degree 1293 1 = 90 degree rotation 1294 2 = 180 degree rotation 1295 3 = 270 degree rotation 1296 1297 If CONFIG_LCD_ROTATION is not defined, the console will be 1298 initialized with 0degree rotation. 1299 1300 CONFIG_LCD_BMP_RLE8 1301 1302 Support drawing of RLE8-compressed bitmaps on the LCD. 1303 1304 CONFIG_I2C_EDID 1305 1306 Enables an 'i2c edid' command which can read EDID 1307 information over I2C from an attached LCD display. 1308 1309- Splash Screen Support: CONFIG_SPLASH_SCREEN 1310 1311 If this option is set, the environment is checked for 1312 a variable "splashimage". If found, the usual display 1313 of logo, copyright and system information on the LCD 1314 is suppressed and the BMP image at the address 1315 specified in "splashimage" is loaded instead. The 1316 console is redirected to the "nulldev", too. This 1317 allows for a "silent" boot where a splash screen is 1318 loaded very quickly after power-on. 1319 1320 CONFIG_SPLASHIMAGE_GUARD 1321 1322 If this option is set, then U-Boot will prevent the environment 1323 variable "splashimage" from being set to a problematic address 1324 (see doc/README.displaying-bmps). 1325 This option is useful for targets where, due to alignment 1326 restrictions, an improperly aligned BMP image will cause a data 1327 abort. If you think you will not have problems with unaligned 1328 accesses (for example because your toolchain prevents them) 1329 there is no need to set this option. 1330 1331 CONFIG_SPLASH_SCREEN_ALIGN 1332 1333 If this option is set the splash image can be freely positioned 1334 on the screen. Environment variable "splashpos" specifies the 1335 position as "x,y". If a positive number is given it is used as 1336 number of pixel from left/top. If a negative number is given it 1337 is used as number of pixel from right/bottom. You can also 1338 specify 'm' for centering the image. 1339 1340 Example: 1341 setenv splashpos m,m 1342 => image at center of screen 1343 1344 setenv splashpos 30,20 1345 => image at x = 30 and y = 20 1346 1347 setenv splashpos -10,m 1348 => vertically centered image 1349 at x = dspWidth - bmpWidth - 9 1350 1351- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP 1352 1353 If this option is set, additionally to standard BMP 1354 images, gzipped BMP images can be displayed via the 1355 splashscreen support or the bmp command. 1356 1357- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8 1358 1359 If this option is set, 8-bit RLE compressed BMP images 1360 can be displayed via the splashscreen support or the 1361 bmp command. 1362 1363- Compression support: 1364 CONFIG_GZIP 1365 1366 Enabled by default to support gzip compressed images. 1367 1368 CONFIG_BZIP2 1369 1370 If this option is set, support for bzip2 compressed 1371 images is included. If not, only uncompressed and gzip 1372 compressed images are supported. 1373 1374 NOTE: the bzip2 algorithm requires a lot of RAM, so 1375 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should 1376 be at least 4MB. 1377 1378- MII/PHY support: 1379 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1380 1381 The clock frequency of the MII bus 1382 1383 CONFIG_PHY_RESET_DELAY 1384 1385 Some PHY like Intel LXT971A need extra delay after 1386 reset before any MII register access is possible. 1387 For such PHY, set this option to the usec delay 1388 required. (minimum 300usec for LXT971A) 1389 1390 CONFIG_PHY_CMD_DELAY (ppc4xx) 1391 1392 Some PHY like Intel LXT971A need extra delay after 1393 command issued before MII status register can be read 1394 1395- IP address: 1396 CONFIG_IPADDR 1397 1398 Define a default value for the IP address to use for 1399 the default Ethernet interface, in case this is not 1400 determined through e.g. bootp. 1401 (Environment variable "ipaddr") 1402 1403- Server IP address: 1404 CONFIG_SERVERIP 1405 1406 Defines a default value for the IP address of a TFTP 1407 server to contact when using the "tftboot" command. 1408 (Environment variable "serverip") 1409 1410 CONFIG_KEEP_SERVERADDR 1411 1412 Keeps the server's MAC address, in the env 'serveraddr' 1413 for passing to bootargs (like Linux's netconsole option) 1414 1415- Gateway IP address: 1416 CONFIG_GATEWAYIP 1417 1418 Defines a default value for the IP address of the 1419 default router where packets to other networks are 1420 sent to. 1421 (Environment variable "gatewayip") 1422 1423- Subnet mask: 1424 CONFIG_NETMASK 1425 1426 Defines a default value for the subnet mask (or 1427 routing prefix) which is used to determine if an IP 1428 address belongs to the local subnet or needs to be 1429 forwarded through a router. 1430 (Environment variable "netmask") 1431 1432- BOOTP Recovery Mode: 1433 CONFIG_BOOTP_RANDOM_DELAY 1434 1435 If you have many targets in a network that try to 1436 boot using BOOTP, you may want to avoid that all 1437 systems send out BOOTP requests at precisely the same 1438 moment (which would happen for instance at recovery 1439 from a power failure, when all systems will try to 1440 boot, thus flooding the BOOTP server. Defining 1441 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1442 inserted before sending out BOOTP requests. The 1443 following delays are inserted then: 1444 1445 1st BOOTP request: delay 0 ... 1 sec 1446 2nd BOOTP request: delay 0 ... 2 sec 1447 3rd BOOTP request: delay 0 ... 4 sec 1448 4th and following 1449 BOOTP requests: delay 0 ... 8 sec 1450 1451 CONFIG_BOOTP_ID_CACHE_SIZE 1452 1453 BOOTP packets are uniquely identified using a 32-bit ID. The 1454 server will copy the ID from client requests to responses and 1455 U-Boot will use this to determine if it is the destination of 1456 an incoming response. Some servers will check that addresses 1457 aren't in use before handing them out (usually using an ARP 1458 ping) and therefore take up to a few hundred milliseconds to 1459 respond. Network congestion may also influence the time it 1460 takes for a response to make it back to the client. If that 1461 time is too long, U-Boot will retransmit requests. In order 1462 to allow earlier responses to still be accepted after these 1463 retransmissions, U-Boot's BOOTP client keeps a small cache of 1464 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1465 cache. The default is to keep IDs for up to four outstanding 1466 requests. Increasing this will allow U-Boot to accept offers 1467 from a BOOTP client in networks with unusually high latency. 1468 1469- DHCP Advanced Options: 1470 You can fine tune the DHCP functionality by defining 1471 CONFIG_BOOTP_* symbols: 1472 1473 CONFIG_BOOTP_NISDOMAIN 1474 CONFIG_BOOTP_BOOTFILESIZE 1475 CONFIG_BOOTP_SEND_HOSTNAME 1476 CONFIG_BOOTP_NTPSERVER 1477 CONFIG_BOOTP_TIMEOFFSET 1478 CONFIG_BOOTP_VENDOREX 1479 CONFIG_BOOTP_MAY_FAIL 1480 1481 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1482 environment variable, not the BOOTP server. 1483 1484 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1485 after the configured retry count, the call will fail 1486 instead of starting over. This can be used to fail over 1487 to Link-local IP address configuration if the DHCP server 1488 is not available. 1489 1490 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1491 to do a dynamic update of a DNS server. To do this, they 1492 need the hostname of the DHCP requester. 1493 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1494 of the "hostname" environment variable is passed as 1495 option 12 to the DHCP server. 1496 1497 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1498 1499 A 32bit value in microseconds for a delay between 1500 receiving a "DHCP Offer" and sending the "DHCP Request". 1501 This fixes a problem with certain DHCP servers that don't 1502 respond 100% of the time to a "DHCP request". E.g. On an 1503 AT91RM9200 processor running at 180MHz, this delay needed 1504 to be *at least* 15,000 usec before a Windows Server 2003 1505 DHCP server would reply 100% of the time. I recommend at 1506 least 50,000 usec to be safe. The alternative is to hope 1507 that one of the retries will be successful but note that 1508 the DHCP timeout and retry process takes a longer than 1509 this delay. 1510 1511 - Link-local IP address negotiation: 1512 Negotiate with other link-local clients on the local network 1513 for an address that doesn't require explicit configuration. 1514 This is especially useful if a DHCP server cannot be guaranteed 1515 to exist in all environments that the device must operate. 1516 1517 See doc/README.link-local for more information. 1518 1519 - MAC address from environment variables 1520 1521 FDT_SEQ_MACADDR_FROM_ENV 1522 1523 Fix-up device tree with MAC addresses fetched sequentially from 1524 environment variables. This config work on assumption that 1525 non-usable ethernet node of device-tree are either not present 1526 or their status has been marked as "disabled". 1527 1528 - CDP Options: 1529 CONFIG_CDP_DEVICE_ID 1530 1531 The device id used in CDP trigger frames. 1532 1533 CONFIG_CDP_DEVICE_ID_PREFIX 1534 1535 A two character string which is prefixed to the MAC address 1536 of the device. 1537 1538 CONFIG_CDP_PORT_ID 1539 1540 A printf format string which contains the ascii name of 1541 the port. Normally is set to "eth%d" which sets 1542 eth0 for the first Ethernet, eth1 for the second etc. 1543 1544 CONFIG_CDP_CAPABILITIES 1545 1546 A 32bit integer which indicates the device capabilities; 1547 0x00000010 for a normal host which does not forwards. 1548 1549 CONFIG_CDP_VERSION 1550 1551 An ascii string containing the version of the software. 1552 1553 CONFIG_CDP_PLATFORM 1554 1555 An ascii string containing the name of the platform. 1556 1557 CONFIG_CDP_TRIGGER 1558 1559 A 32bit integer sent on the trigger. 1560 1561 CONFIG_CDP_POWER_CONSUMPTION 1562 1563 A 16bit integer containing the power consumption of the 1564 device in .1 of milliwatts. 1565 1566 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1567 1568 A byte containing the id of the VLAN. 1569 1570- Status LED: CONFIG_LED_STATUS 1571 1572 Several configurations allow to display the current 1573 status using a LED. For instance, the LED will blink 1574 fast while running U-Boot code, stop blinking as 1575 soon as a reply to a BOOTP request was received, and 1576 start blinking slow once the Linux kernel is running 1577 (supported by a status LED driver in the Linux 1578 kernel). Defining CONFIG_LED_STATUS enables this 1579 feature in U-Boot. 1580 1581 Additional options: 1582 1583 CONFIG_LED_STATUS_GPIO 1584 The status LED can be connected to a GPIO pin. 1585 In such cases, the gpio_led driver can be used as a 1586 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1587 to include the gpio_led driver in the U-Boot binary. 1588 1589 CONFIG_GPIO_LED_INVERTED_TABLE 1590 Some GPIO connected LEDs may have inverted polarity in which 1591 case the GPIO high value corresponds to LED off state and 1592 GPIO low value corresponds to LED on state. 1593 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1594 with a list of GPIO LEDs that have inverted polarity. 1595 1596- I2C Support: CONFIG_SYS_I2C 1597 1598 This enable the NEW i2c subsystem, and will allow you to use 1599 i2c commands at the u-boot command line (as long as you set 1600 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c 1601 based realtime clock chips or other i2c devices. See 1602 common/cmd_i2c.c for a description of the command line 1603 interface. 1604 1605 ported i2c driver to the new framework: 1606 - drivers/i2c/soft_i2c.c: 1607 - activate first bus with CONFIG_SYS_I2C_SOFT define 1608 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1609 for defining speed and slave address 1610 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1611 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1612 for defining speed and slave address 1613 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1614 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1615 for defining speed and slave address 1616 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1617 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1618 for defining speed and slave address 1619 1620 - drivers/i2c/fsl_i2c.c: 1621 - activate i2c driver with CONFIG_SYS_I2C_FSL 1622 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1623 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1624 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1625 bus. 1626 - If your board supports a second fsl i2c bus, define 1627 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1628 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1629 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1630 second bus. 1631 1632 - drivers/i2c/tegra_i2c.c: 1633 - activate this driver with CONFIG_SYS_I2C_TEGRA 1634 - This driver adds 4 i2c buses with a fix speed from 1635 100000 and the slave addr 0! 1636 1637 - drivers/i2c/ppc4xx_i2c.c 1638 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1639 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1640 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1641 1642 - drivers/i2c/i2c_mxc.c 1643 - activate this driver with CONFIG_SYS_I2C_MXC 1644 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1645 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1646 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1647 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1648 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1649 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1650 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1651 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1652 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1653 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1654 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1655 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1656 If those defines are not set, default value is 100000 1657 for speed, and 0 for slave. 1658 1659 - drivers/i2c/rcar_i2c.c: 1660 - activate this driver with CONFIG_SYS_I2C_RCAR 1661 - This driver adds 4 i2c buses 1662 1663 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 1664 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 1665 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 1666 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 1667 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 1668 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 1669 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 1670 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 1671 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses 1672 1673 - drivers/i2c/sh_i2c.c: 1674 - activate this driver with CONFIG_SYS_I2C_SH 1675 - This driver adds from 2 to 5 i2c buses 1676 1677 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1678 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1679 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1680 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1681 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1682 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1683 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1684 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1685 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1686 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1687 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1688 1689 - drivers/i2c/omap24xx_i2c.c 1690 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1691 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1692 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1693 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1694 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1695 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1696 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1697 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1698 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1699 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1700 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1701 1702 - drivers/i2c/zynq_i2c.c 1703 - activate this driver with CONFIG_SYS_I2C_ZYNQ 1704 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting 1705 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr 1706 1707 - drivers/i2c/s3c24x0_i2c.c: 1708 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1709 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1710 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1711 with a fix speed from 100000 and the slave addr 0! 1712 1713 - drivers/i2c/ihs_i2c.c 1714 - activate this driver with CONFIG_SYS_I2C_IHS 1715 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1716 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1717 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1718 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1719 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1720 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1721 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1722 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1723 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1724 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1725 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1726 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1727 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1728 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1729 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1730 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1731 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1732 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1733 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1734 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1735 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1736 1737 additional defines: 1738 1739 CONFIG_SYS_NUM_I2C_BUSES 1740 Hold the number of i2c buses you want to use. 1741 1742 CONFIG_SYS_I2C_DIRECT_BUS 1743 define this, if you don't use i2c muxes on your hardware. 1744 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1745 omit this define. 1746 1747 CONFIG_SYS_I2C_MAX_HOPS 1748 define how many muxes are maximal consecutively connected 1749 on one i2c bus. If you not use i2c muxes, omit this 1750 define. 1751 1752 CONFIG_SYS_I2C_BUSES 1753 hold a list of buses you want to use, only used if 1754 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1755 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1756 CONFIG_SYS_NUM_I2C_BUSES = 9: 1757 1758 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1759 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1760 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1761 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1762 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1763 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1764 {1, {I2C_NULL_HOP}}, \ 1765 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1766 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1767 } 1768 1769 which defines 1770 bus 0 on adapter 0 without a mux 1771 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1772 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1773 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1774 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1775 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1776 bus 6 on adapter 1 without a mux 1777 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1778 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1779 1780 If you do not have i2c muxes on your board, omit this define. 1781 1782- Legacy I2C Support: 1783 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1784 then the following macros need to be defined (examples are 1785 from include/configs/lwmon.h): 1786 1787 I2C_INIT 1788 1789 (Optional). Any commands necessary to enable the I2C 1790 controller or configure ports. 1791 1792 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1793 1794 I2C_ACTIVE 1795 1796 The code necessary to make the I2C data line active 1797 (driven). If the data line is open collector, this 1798 define can be null. 1799 1800 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1801 1802 I2C_TRISTATE 1803 1804 The code necessary to make the I2C data line tri-stated 1805 (inactive). If the data line is open collector, this 1806 define can be null. 1807 1808 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1809 1810 I2C_READ 1811 1812 Code that returns true if the I2C data line is high, 1813 false if it is low. 1814 1815 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1816 1817 I2C_SDA(bit) 1818 1819 If <bit> is true, sets the I2C data line high. If it 1820 is false, it clears it (low). 1821 1822 eg: #define I2C_SDA(bit) \ 1823 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1824 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1825 1826 I2C_SCL(bit) 1827 1828 If <bit> is true, sets the I2C clock line high. If it 1829 is false, it clears it (low). 1830 1831 eg: #define I2C_SCL(bit) \ 1832 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1833 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1834 1835 I2C_DELAY 1836 1837 This delay is invoked four times per clock cycle so this 1838 controls the rate of data transfer. The data rate thus 1839 is 1 / (I2C_DELAY * 4). Often defined to be something 1840 like: 1841 1842 #define I2C_DELAY udelay(2) 1843 1844 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1845 1846 If your arch supports the generic GPIO framework (asm/gpio.h), 1847 then you may alternatively define the two GPIOs that are to be 1848 used as SCL / SDA. Any of the previous I2C_xxx macros will 1849 have GPIO-based defaults assigned to them as appropriate. 1850 1851 You should define these to the GPIO value as given directly to 1852 the generic GPIO functions. 1853 1854 CONFIG_SYS_I2C_INIT_BOARD 1855 1856 When a board is reset during an i2c bus transfer 1857 chips might think that the current transfer is still 1858 in progress. On some boards it is possible to access 1859 the i2c SCLK line directly, either by using the 1860 processor pin as a GPIO or by having a second pin 1861 connected to the bus. If this option is defined a 1862 custom i2c_init_board() routine in boards/xxx/board.c 1863 is run early in the boot sequence. 1864 1865 CONFIG_I2C_MULTI_BUS 1866 1867 This option allows the use of multiple I2C buses, each of which 1868 must have a controller. At any point in time, only one bus is 1869 active. To switch to a different bus, use the 'i2c dev' command. 1870 Note that bus numbering is zero-based. 1871 1872 CONFIG_SYS_I2C_NOPROBES 1873 1874 This option specifies a list of I2C devices that will be skipped 1875 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1876 is set, specify a list of bus-device pairs. Otherwise, specify 1877 a 1D array of device addresses 1878 1879 e.g. 1880 #undef CONFIG_I2C_MULTI_BUS 1881 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1882 1883 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1884 1885 #define CONFIG_I2C_MULTI_BUS 1886 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1887 1888 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1889 1890 CONFIG_SYS_SPD_BUS_NUM 1891 1892 If defined, then this indicates the I2C bus number for DDR SPD. 1893 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1894 1895 CONFIG_SYS_RTC_BUS_NUM 1896 1897 If defined, then this indicates the I2C bus number for the RTC. 1898 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1899 1900 CONFIG_SOFT_I2C_READ_REPEATED_START 1901 1902 defining this will force the i2c_read() function in 1903 the soft_i2c driver to perform an I2C repeated start 1904 between writing the address pointer and reading the 1905 data. If this define is omitted the default behaviour 1906 of doing a stop-start sequence will be used. Most I2C 1907 devices can use either method, but some require one or 1908 the other. 1909 1910- SPI Support: CONFIG_SPI 1911 1912 Enables SPI driver (so far only tested with 1913 SPI EEPROM, also an instance works with Crystal A/D and 1914 D/As on the SACSng board) 1915 1916 CONFIG_SOFT_SPI 1917 1918 Enables a software (bit-bang) SPI driver rather than 1919 using hardware support. This is a general purpose 1920 driver that only requires three general I/O port pins 1921 (two outputs, one input) to function. If this is 1922 defined, the board configuration must define several 1923 SPI configuration items (port pins to use, etc). For 1924 an example, see include/configs/sacsng.h. 1925 1926 CONFIG_SYS_SPI_MXC_WAIT 1927 Timeout for waiting until spi transfer completed. 1928 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1929 1930- FPGA Support: CONFIG_FPGA 1931 1932 Enables FPGA subsystem. 1933 1934 CONFIG_FPGA_<vendor> 1935 1936 Enables support for specific chip vendors. 1937 (ALTERA, XILINX) 1938 1939 CONFIG_FPGA_<family> 1940 1941 Enables support for FPGA family. 1942 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1943 1944 CONFIG_FPGA_COUNT 1945 1946 Specify the number of FPGA devices to support. 1947 1948 CONFIG_SYS_FPGA_PROG_FEEDBACK 1949 1950 Enable printing of hash marks during FPGA configuration. 1951 1952 CONFIG_SYS_FPGA_CHECK_BUSY 1953 1954 Enable checks on FPGA configuration interface busy 1955 status by the configuration function. This option 1956 will require a board or device specific function to 1957 be written. 1958 1959 CONFIG_FPGA_DELAY 1960 1961 If defined, a function that provides delays in the FPGA 1962 configuration driver. 1963 1964 CONFIG_SYS_FPGA_CHECK_CTRLC 1965 Allow Control-C to interrupt FPGA configuration 1966 1967 CONFIG_SYS_FPGA_CHECK_ERROR 1968 1969 Check for configuration errors during FPGA bitfile 1970 loading. For example, abort during Virtex II 1971 configuration if the INIT_B line goes low (which 1972 indicated a CRC error). 1973 1974 CONFIG_SYS_FPGA_WAIT_INIT 1975 1976 Maximum time to wait for the INIT_B line to de-assert 1977 after PROB_B has been de-asserted during a Virtex II 1978 FPGA configuration sequence. The default time is 500 1979 ms. 1980 1981 CONFIG_SYS_FPGA_WAIT_BUSY 1982 1983 Maximum time to wait for BUSY to de-assert during 1984 Virtex II FPGA configuration. The default is 5 ms. 1985 1986 CONFIG_SYS_FPGA_WAIT_CONFIG 1987 1988 Time to wait after FPGA configuration. The default is 1989 200 ms. 1990 1991- Configuration Management: 1992 CONFIG_BUILD_TARGET 1993 1994 Some SoCs need special image types (e.g. U-Boot binary 1995 with a special header) as build targets. By defining 1996 CONFIG_BUILD_TARGET in the SoC / board header, this 1997 special image will be automatically built upon calling 1998 make / buildman. 1999 2000 CONFIG_IDENT_STRING 2001 2002 If defined, this string will be added to the U-Boot 2003 version information (U_BOOT_VERSION) 2004 2005- Vendor Parameter Protection: 2006 2007 U-Boot considers the values of the environment 2008 variables "serial#" (Board Serial Number) and 2009 "ethaddr" (Ethernet Address) to be parameters that 2010 are set once by the board vendor / manufacturer, and 2011 protects these variables from casual modification by 2012 the user. Once set, these variables are read-only, 2013 and write or delete attempts are rejected. You can 2014 change this behaviour: 2015 2016 If CONFIG_ENV_OVERWRITE is #defined in your config 2017 file, the write protection for vendor parameters is 2018 completely disabled. Anybody can change or delete 2019 these parameters. 2020 2021 Alternatively, if you define _both_ an ethaddr in the 2022 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 2023 Ethernet address is installed in the environment, 2024 which can be changed exactly ONCE by the user. [The 2025 serial# is unaffected by this, i. e. it remains 2026 read-only.] 2027 2028 The same can be accomplished in a more flexible way 2029 for any variable by configuring the type of access 2030 to allow for those variables in the ".flags" variable 2031 or define CONFIG_ENV_FLAGS_LIST_STATIC. 2032 2033- Protected RAM: 2034 CONFIG_PRAM 2035 2036 Define this variable to enable the reservation of 2037 "protected RAM", i. e. RAM which is not overwritten 2038 by U-Boot. Define CONFIG_PRAM to hold the number of 2039 kB you want to reserve for pRAM. You can overwrite 2040 this default value by defining an environment 2041 variable "pram" to the number of kB you want to 2042 reserve. Note that the board info structure will 2043 still show the full amount of RAM. If pRAM is 2044 reserved, a new environment variable "mem" will 2045 automatically be defined to hold the amount of 2046 remaining RAM in a form that can be passed as boot 2047 argument to Linux, for instance like that: 2048 2049 setenv bootargs ... mem=\${mem} 2050 saveenv 2051 2052 This way you can tell Linux not to use this memory, 2053 either, which results in a memory region that will 2054 not be affected by reboots. 2055 2056 *WARNING* If your board configuration uses automatic 2057 detection of the RAM size, you must make sure that 2058 this memory test is non-destructive. So far, the 2059 following board configurations are known to be 2060 "pRAM-clean": 2061 2062 IVMS8, IVML24, SPD8xx, 2063 HERMES, IP860, RPXlite, LWMON, 2064 FLAGADM 2065 2066- Access to physical memory region (> 4GB) 2067 Some basic support is provided for operations on memory not 2068 normally accessible to U-Boot - e.g. some architectures 2069 support access to more than 4GB of memory on 32-bit 2070 machines using physical address extension or similar. 2071 Define CONFIG_PHYSMEM to access this basic support, which 2072 currently only supports clearing the memory. 2073 2074- Error Recovery: 2075 CONFIG_NET_RETRY_COUNT 2076 2077 This variable defines the number of retries for 2078 network operations like ARP, RARP, TFTP, or BOOTP 2079 before giving up the operation. If not defined, a 2080 default value of 5 is used. 2081 2082 CONFIG_ARP_TIMEOUT 2083 2084 Timeout waiting for an ARP reply in milliseconds. 2085 2086 CONFIG_NFS_TIMEOUT 2087 2088 Timeout in milliseconds used in NFS protocol. 2089 If you encounter "ERROR: Cannot umount" in nfs command, 2090 try longer timeout such as 2091 #define CONFIG_NFS_TIMEOUT 10000UL 2092 2093- Command Interpreter: 2094 CONFIG_SYS_PROMPT_HUSH_PS2 2095 2096 This defines the secondary prompt string, which is 2097 printed when the command interpreter needs more input 2098 to complete a command. Usually "> ". 2099 2100 Note: 2101 2102 In the current implementation, the local variables 2103 space and global environment variables space are 2104 separated. Local variables are those you define by 2105 simply typing `name=value'. To access a local 2106 variable later on, you have write `$name' or 2107 `${name}'; to execute the contents of a variable 2108 directly type `$name' at the command prompt. 2109 2110 Global environment variables are those you use 2111 setenv/printenv to work with. To run a command stored 2112 in such a variable, you need to use the run command, 2113 and you must not use the '$' sign to access them. 2114 2115 To store commands and special characters in a 2116 variable, please use double quotation marks 2117 surrounding the whole text of the variable, instead 2118 of the backslashes before semicolons and special 2119 symbols. 2120 2121- Command Line Editing and History: 2122 CONFIG_CMDLINE_PS_SUPPORT 2123 2124 Enable support for changing the command prompt string 2125 at run-time. Only static string is supported so far. 2126 The string is obtained from environment variables PS1 2127 and PS2. 2128 2129- Default Environment: 2130 CONFIG_EXTRA_ENV_SETTINGS 2131 2132 Define this to contain any number of null terminated 2133 strings (variable = value pairs) that will be part of 2134 the default environment compiled into the boot image. 2135 2136 For example, place something like this in your 2137 board's config file: 2138 2139 #define CONFIG_EXTRA_ENV_SETTINGS \ 2140 "myvar1=value1\0" \ 2141 "myvar2=value2\0" 2142 2143 Warning: This method is based on knowledge about the 2144 internal format how the environment is stored by the 2145 U-Boot code. This is NOT an official, exported 2146 interface! Although it is unlikely that this format 2147 will change soon, there is no guarantee either. 2148 You better know what you are doing here. 2149 2150 Note: overly (ab)use of the default environment is 2151 discouraged. Make sure to check other ways to preset 2152 the environment like the "source" command or the 2153 boot command first. 2154 2155 CONFIG_DELAY_ENVIRONMENT 2156 2157 Normally the environment is loaded when the board is 2158 initialised so that it is available to U-Boot. This inhibits 2159 that so that the environment is not available until 2160 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 2161 this is instead controlled by the value of 2162 /config/load-environment. 2163 2164- Serial Flash support 2165 Usage requires an initial 'sf probe' to define the serial 2166 flash parameters, followed by read/write/erase/update 2167 commands. 2168 2169 The following defaults may be provided by the platform 2170 to handle the common case when only a single serial 2171 flash is present on the system. 2172 2173 CONFIG_SF_DEFAULT_BUS Bus identifier 2174 CONFIG_SF_DEFAULT_CS Chip-select 2175 CONFIG_SF_DEFAULT_MODE (see include/spi.h) 2176 CONFIG_SF_DEFAULT_SPEED in Hz 2177 2178 2179- TFTP Fixed UDP Port: 2180 CONFIG_TFTP_PORT 2181 2182 If this is defined, the environment variable tftpsrcp 2183 is used to supply the TFTP UDP source port value. 2184 If tftpsrcp isn't defined, the normal pseudo-random port 2185 number generator is used. 2186 2187 Also, the environment variable tftpdstp is used to supply 2188 the TFTP UDP destination port value. If tftpdstp isn't 2189 defined, the normal port 69 is used. 2190 2191 The purpose for tftpsrcp is to allow a TFTP server to 2192 blindly start the TFTP transfer using the pre-configured 2193 target IP address and UDP port. This has the effect of 2194 "punching through" the (Windows XP) firewall, allowing 2195 the remainder of the TFTP transfer to proceed normally. 2196 A better solution is to properly configure the firewall, 2197 but sometimes that is not allowed. 2198 2199- Show boot progress: 2200 CONFIG_SHOW_BOOT_PROGRESS 2201 2202 Defining this option allows to add some board- 2203 specific code (calling a user-provided function 2204 "show_boot_progress(int)") that enables you to show 2205 the system's boot progress on some display (for 2206 example, some LED's) on your board. At the moment, 2207 the following checkpoints are implemented: 2208 2209 2210Legacy uImage format: 2211 2212 Arg Where When 2213 1 common/cmd_bootm.c before attempting to boot an image 2214 -1 common/cmd_bootm.c Image header has bad magic number 2215 2 common/cmd_bootm.c Image header has correct magic number 2216 -2 common/cmd_bootm.c Image header has bad checksum 2217 3 common/cmd_bootm.c Image header has correct checksum 2218 -3 common/cmd_bootm.c Image data has bad checksum 2219 4 common/cmd_bootm.c Image data has correct checksum 2220 -4 common/cmd_bootm.c Image is for unsupported architecture 2221 5 common/cmd_bootm.c Architecture check OK 2222 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi) 2223 6 common/cmd_bootm.c Image Type check OK 2224 -6 common/cmd_bootm.c gunzip uncompression error 2225 -7 common/cmd_bootm.c Unimplemented compression type 2226 7 common/cmd_bootm.c Uncompression OK 2227 8 common/cmd_bootm.c No uncompress/copy overwrite error 2228 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 2229 2230 9 common/image.c Start initial ramdisk verification 2231 -10 common/image.c Ramdisk header has bad magic number 2232 -11 common/image.c Ramdisk header has bad checksum 2233 10 common/image.c Ramdisk header is OK 2234 -12 common/image.c Ramdisk data has bad checksum 2235 11 common/image.c Ramdisk data has correct checksum 2236 12 common/image.c Ramdisk verification complete, start loading 2237 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk) 2238 13 common/image.c Start multifile image verification 2239 14 common/image.c No initial ramdisk, no multifile, continue. 2240 2241 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS 2242 2243 -30 arch/powerpc/lib/board.c Fatal error, hang the system 2244 -31 post/post.c POST test failed, detected by post_output_backlog() 2245 -32 post/post.c POST test failed, detected by post_run_single() 2246 2247 34 common/cmd_doc.c before loading a Image from a DOC device 2248 -35 common/cmd_doc.c Bad usage of "doc" command 2249 35 common/cmd_doc.c correct usage of "doc" command 2250 -36 common/cmd_doc.c No boot device 2251 36 common/cmd_doc.c correct boot device 2252 -37 common/cmd_doc.c Unknown Chip ID on boot device 2253 37 common/cmd_doc.c correct chip ID found, device available 2254 -38 common/cmd_doc.c Read Error on boot device 2255 38 common/cmd_doc.c reading Image header from DOC device OK 2256 -39 common/cmd_doc.c Image header has bad magic number 2257 39 common/cmd_doc.c Image header has correct magic number 2258 -40 common/cmd_doc.c Error reading Image from DOC device 2259 40 common/cmd_doc.c Image header has correct magic number 2260 41 common/cmd_ide.c before loading a Image from a IDE device 2261 -42 common/cmd_ide.c Bad usage of "ide" command 2262 42 common/cmd_ide.c correct usage of "ide" command 2263 -43 common/cmd_ide.c No boot device 2264 43 common/cmd_ide.c boot device found 2265 -44 common/cmd_ide.c Device not available 2266 44 common/cmd_ide.c Device available 2267 -45 common/cmd_ide.c wrong partition selected 2268 45 common/cmd_ide.c partition selected 2269 -46 common/cmd_ide.c Unknown partition table 2270 46 common/cmd_ide.c valid partition table found 2271 -47 common/cmd_ide.c Invalid partition type 2272 47 common/cmd_ide.c correct partition type 2273 -48 common/cmd_ide.c Error reading Image Header on boot device 2274 48 common/cmd_ide.c reading Image Header from IDE device OK 2275 -49 common/cmd_ide.c Image header has bad magic number 2276 49 common/cmd_ide.c Image header has correct magic number 2277 -50 common/cmd_ide.c Image header has bad checksum 2278 50 common/cmd_ide.c Image header has correct checksum 2279 -51 common/cmd_ide.c Error reading Image from IDE device 2280 51 common/cmd_ide.c reading Image from IDE device OK 2281 52 common/cmd_nand.c before loading a Image from a NAND device 2282 -53 common/cmd_nand.c Bad usage of "nand" command 2283 53 common/cmd_nand.c correct usage of "nand" command 2284 -54 common/cmd_nand.c No boot device 2285 54 common/cmd_nand.c boot device found 2286 -55 common/cmd_nand.c Unknown Chip ID on boot device 2287 55 common/cmd_nand.c correct chip ID found, device available 2288 -56 common/cmd_nand.c Error reading Image Header on boot device 2289 56 common/cmd_nand.c reading Image Header from NAND device OK 2290 -57 common/cmd_nand.c Image header has bad magic number 2291 57 common/cmd_nand.c Image header has correct magic number 2292 -58 common/cmd_nand.c Error reading Image from NAND device 2293 58 common/cmd_nand.c reading Image from NAND device OK 2294 2295 -60 common/env_common.c Environment has a bad CRC, using default 2296 2297 64 net/eth.c starting with Ethernet configuration. 2298 -64 net/eth.c no Ethernet found. 2299 65 net/eth.c Ethernet found. 2300 2301 -80 common/cmd_net.c usage wrong 2302 80 common/cmd_net.c before calling net_loop() 2303 -81 common/cmd_net.c some error in net_loop() occurred 2304 81 common/cmd_net.c net_loop() back without error 2305 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 2306 82 common/cmd_net.c trying automatic boot 2307 83 common/cmd_net.c running "source" command 2308 -83 common/cmd_net.c some error in automatic boot or "source" command 2309 84 common/cmd_net.c end without errors 2310 2311FIT uImage format: 2312 2313 Arg Where When 2314 100 common/cmd_bootm.c Kernel FIT Image has correct format 2315 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format 2316 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration 2317 -101 common/cmd_bootm.c Can't get configuration for kernel subimage 2318 102 common/cmd_bootm.c Kernel unit name specified 2319 -103 common/cmd_bootm.c Can't get kernel subimage node offset 2320 103 common/cmd_bootm.c Found configuration node 2321 104 common/cmd_bootm.c Got kernel subimage node offset 2322 -104 common/cmd_bootm.c Kernel subimage hash verification failed 2323 105 common/cmd_bootm.c Kernel subimage hash verification OK 2324 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture 2325 106 common/cmd_bootm.c Architecture check OK 2326 -106 common/cmd_bootm.c Kernel subimage has wrong type 2327 107 common/cmd_bootm.c Kernel subimage type OK 2328 -107 common/cmd_bootm.c Can't get kernel subimage data/size 2329 108 common/cmd_bootm.c Got kernel subimage data/size 2330 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT) 2331 -109 common/cmd_bootm.c Can't get kernel subimage type 2332 -110 common/cmd_bootm.c Can't get kernel subimage comp 2333 -111 common/cmd_bootm.c Can't get kernel subimage os 2334 -112 common/cmd_bootm.c Can't get kernel subimage load address 2335 -113 common/cmd_bootm.c Image uncompress/copy overwrite error 2336 2337 120 common/image.c Start initial ramdisk verification 2338 -120 common/image.c Ramdisk FIT image has incorrect format 2339 121 common/image.c Ramdisk FIT image has correct format 2340 122 common/image.c No ramdisk subimage unit name, using configuration 2341 -122 common/image.c Can't get configuration for ramdisk subimage 2342 123 common/image.c Ramdisk unit name specified 2343 -124 common/image.c Can't get ramdisk subimage node offset 2344 125 common/image.c Got ramdisk subimage node offset 2345 -125 common/image.c Ramdisk subimage hash verification failed 2346 126 common/image.c Ramdisk subimage hash verification OK 2347 -126 common/image.c Ramdisk subimage for unsupported architecture 2348 127 common/image.c Architecture check OK 2349 -127 common/image.c Can't get ramdisk subimage data/size 2350 128 common/image.c Got ramdisk subimage data/size 2351 129 common/image.c Can't get ramdisk load address 2352 -129 common/image.c Got ramdisk load address 2353 2354 -130 common/cmd_doc.c Incorrect FIT image format 2355 131 common/cmd_doc.c FIT image format OK 2356 2357 -140 common/cmd_ide.c Incorrect FIT image format 2358 141 common/cmd_ide.c FIT image format OK 2359 2360 -150 common/cmd_nand.c Incorrect FIT image format 2361 151 common/cmd_nand.c FIT image format OK 2362 2363- Standalone program support: 2364 CONFIG_STANDALONE_LOAD_ADDR 2365 2366 This option defines a board specific value for the 2367 address where standalone program gets loaded, thus 2368 overwriting the architecture dependent default 2369 settings. 2370 2371- Frame Buffer Address: 2372 CONFIG_FB_ADDR 2373 2374 Define CONFIG_FB_ADDR if you want to use specific 2375 address for frame buffer. This is typically the case 2376 when using a graphics controller has separate video 2377 memory. U-Boot will then place the frame buffer at 2378 the given address instead of dynamically reserving it 2379 in system RAM by calling lcd_setmem(), which grabs 2380 the memory for the frame buffer depending on the 2381 configured panel size. 2382 2383 Please see board_init_f function. 2384 2385- Automatic software updates via TFTP server 2386 CONFIG_UPDATE_TFTP 2387 CONFIG_UPDATE_TFTP_CNT_MAX 2388 CONFIG_UPDATE_TFTP_MSEC_MAX 2389 2390 These options enable and control the auto-update feature; 2391 for a more detailed description refer to doc/README.update. 2392 2393- MTD Support (mtdparts command, UBI support) 2394 CONFIG_MTD_UBI_WL_THRESHOLD 2395 This parameter defines the maximum difference between the highest 2396 erase counter value and the lowest erase counter value of eraseblocks 2397 of UBI devices. When this threshold is exceeded, UBI starts performing 2398 wear leveling by means of moving data from eraseblock with low erase 2399 counter to eraseblocks with high erase counter. 2400 2401 The default value should be OK for SLC NAND flashes, NOR flashes and 2402 other flashes which have eraseblock life-cycle 100000 or more. 2403 However, in case of MLC NAND flashes which typically have eraseblock 2404 life-cycle less than 10000, the threshold should be lessened (e.g., 2405 to 128 or 256, although it does not have to be power of 2). 2406 2407 default: 4096 2408 2409 CONFIG_MTD_UBI_BEB_LIMIT 2410 This option specifies the maximum bad physical eraseblocks UBI 2411 expects on the MTD device (per 1024 eraseblocks). If the 2412 underlying flash does not admit of bad eraseblocks (e.g. NOR 2413 flash), this value is ignored. 2414 2415 NAND datasheets often specify the minimum and maximum NVM 2416 (Number of Valid Blocks) for the flashes' endurance lifetime. 2417 The maximum expected bad eraseblocks per 1024 eraseblocks 2418 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2419 which gives 20 for most NANDs (MaxNVB is basically the total 2420 count of eraseblocks on the chip). 2421 2422 To put it differently, if this value is 20, UBI will try to 2423 reserve about 1.9% of physical eraseblocks for bad blocks 2424 handling. And that will be 1.9% of eraseblocks on the entire 2425 NAND chip, not just the MTD partition UBI attaches. This means 2426 that if you have, say, a NAND flash chip admits maximum 40 bad 2427 eraseblocks, and it is split on two MTD partitions of the same 2428 size, UBI will reserve 40 eraseblocks when attaching a 2429 partition. 2430 2431 default: 20 2432 2433 CONFIG_MTD_UBI_FASTMAP 2434 Fastmap is a mechanism which allows attaching an UBI device 2435 in nearly constant time. Instead of scanning the whole MTD device it 2436 only has to locate a checkpoint (called fastmap) on the device. 2437 The on-flash fastmap contains all information needed to attach 2438 the device. Using fastmap makes only sense on large devices where 2439 attaching by scanning takes long. UBI will not automatically install 2440 a fastmap on old images, but you can set the UBI parameter 2441 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2442 that fastmap-enabled images are still usable with UBI implementations 2443 without fastmap support. On typical flash devices the whole fastmap 2444 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2445 2446 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2447 Set this parameter to enable fastmap automatically on images 2448 without a fastmap. 2449 default: 0 2450 2451 CONFIG_MTD_UBI_FM_DEBUG 2452 Enable UBI fastmap debug 2453 default: 0 2454 2455- SPL framework 2456 CONFIG_SPL 2457 Enable building of SPL globally. 2458 2459 CONFIG_SPL_LDSCRIPT 2460 LDSCRIPT for linking the SPL binary. 2461 2462 CONFIG_SPL_MAX_FOOTPRINT 2463 Maximum size in memory allocated to the SPL, BSS included. 2464 When defined, the linker checks that the actual memory 2465 used by SPL from _start to __bss_end does not exceed it. 2466 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2467 must not be both defined at the same time. 2468 2469 CONFIG_SPL_MAX_SIZE 2470 Maximum size of the SPL image (text, data, rodata, and 2471 linker lists sections), BSS excluded. 2472 When defined, the linker checks that the actual size does 2473 not exceed it. 2474 2475 CONFIG_SPL_TEXT_BASE 2476 TEXT_BASE for linking the SPL binary. 2477 2478 CONFIG_SPL_RELOC_TEXT_BASE 2479 Address to relocate to. If unspecified, this is equal to 2480 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2481 2482 CONFIG_SPL_BSS_START_ADDR 2483 Link address for the BSS within the SPL binary. 2484 2485 CONFIG_SPL_BSS_MAX_SIZE 2486 Maximum size in memory allocated to the SPL BSS. 2487 When defined, the linker checks that the actual memory used 2488 by SPL from __bss_start to __bss_end does not exceed it. 2489 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2490 must not be both defined at the same time. 2491 2492 CONFIG_SPL_STACK 2493 Adress of the start of the stack SPL will use 2494 2495 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2496 When defined, SPL will panic() if the image it has 2497 loaded does not have a signature. 2498 Defining this is useful when code which loads images 2499 in SPL cannot guarantee that absolutely all read errors 2500 will be caught. 2501 An example is the LPC32XX MLC NAND driver, which will 2502 consider that a completely unreadable NAND block is bad, 2503 and thus should be skipped silently. 2504 2505 CONFIG_SPL_RELOC_STACK 2506 Adress of the start of the stack SPL will use after 2507 relocation. If unspecified, this is equal to 2508 CONFIG_SPL_STACK. 2509 2510 CONFIG_SYS_SPL_MALLOC_START 2511 Starting address of the malloc pool used in SPL. 2512 When this option is set the full malloc is used in SPL and 2513 it is set up by spl_init() and before that, the simple malloc() 2514 can be used if CONFIG_SYS_MALLOC_F is defined. 2515 2516 CONFIG_SYS_SPL_MALLOC_SIZE 2517 The size of the malloc pool used in SPL. 2518 2519 CONFIG_SPL_OS_BOOT 2520 Enable booting directly to an OS from SPL. 2521 See also: doc/README.falcon 2522 2523 CONFIG_SPL_DISPLAY_PRINT 2524 For ARM, enable an optional function to print more information 2525 about the running system. 2526 2527 CONFIG_SPL_INIT_MINIMAL 2528 Arch init code should be built for a very small image 2529 2530 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2531 Partition on the MMC to load U-Boot from when the MMC is being 2532 used in raw mode 2533 2534 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2535 Sector to load kernel uImage from when MMC is being 2536 used in raw mode (for Falcon mode) 2537 2538 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2539 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2540 Sector and number of sectors to load kernel argument 2541 parameters from when MMC is being used in raw mode 2542 (for falcon mode) 2543 2544 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 2545 Partition on the MMC to load U-Boot from when the MMC is being 2546 used in fs mode 2547 2548 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2549 Filename to read to load U-Boot when reading from filesystem 2550 2551 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2552 Filename to read to load kernel uImage when reading 2553 from filesystem (for Falcon mode) 2554 2555 CONFIG_SPL_FS_LOAD_ARGS_NAME 2556 Filename to read to load kernel argument parameters 2557 when reading from filesystem (for Falcon mode) 2558 2559 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2560 Set this for NAND SPL on PPC mpc83xx targets, so that 2561 start.S waits for the rest of the SPL to load before 2562 continuing (the hardware starts execution after just 2563 loading the first page rather than the full 4K). 2564 2565 CONFIG_SPL_SKIP_RELOCATE 2566 Avoid SPL relocation 2567 2568 CONFIG_SPL_NAND_BASE 2569 Include nand_base.c in the SPL. Requires 2570 CONFIG_SPL_NAND_DRIVERS. 2571 2572 CONFIG_SPL_NAND_DRIVERS 2573 SPL uses normal NAND drivers, not minimal drivers. 2574 2575 CONFIG_SPL_NAND_IDENT 2576 SPL uses the chip ID list to identify the NAND flash. 2577 Requires CONFIG_SPL_NAND_BASE. 2578 2579 CONFIG_SPL_NAND_ECC 2580 Include standard software ECC in the SPL 2581 2582 CONFIG_SPL_NAND_SIMPLE 2583 Support for NAND boot using simple NAND drivers that 2584 expose the cmd_ctrl() interface. 2585 2586 CONFIG_SPL_UBI 2587 Support for a lightweight UBI (fastmap) scanner and 2588 loader 2589 2590 CONFIG_SPL_NAND_RAW_ONLY 2591 Support to boot only raw u-boot.bin images. Use this only 2592 if you need to save space. 2593 2594 CONFIG_SPL_COMMON_INIT_DDR 2595 Set for common ddr init with serial presence detect in 2596 SPL binary. 2597 2598 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2599 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2600 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2601 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2602 CONFIG_SYS_NAND_ECCBYTES 2603 Defines the size and behavior of the NAND that SPL uses 2604 to read U-Boot 2605 2606 CONFIG_SPL_NAND_BOOT 2607 Add support NAND boot 2608 2609 CONFIG_SYS_NAND_U_BOOT_OFFS 2610 Location in NAND to read U-Boot from 2611 2612 CONFIG_SYS_NAND_U_BOOT_DST 2613 Location in memory to load U-Boot to 2614 2615 CONFIG_SYS_NAND_U_BOOT_SIZE 2616 Size of image to load 2617 2618 CONFIG_SYS_NAND_U_BOOT_START 2619 Entry point in loaded image to jump to 2620 2621 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2622 Define this if you need to first read the OOB and then the 2623 data. This is used, for example, on davinci platforms. 2624 2625 CONFIG_SPL_RAM_DEVICE 2626 Support for running image already present in ram, in SPL binary 2627 2628 CONFIG_SPL_PAD_TO 2629 Image offset to which the SPL should be padded before appending 2630 the SPL payload. By default, this is defined as 2631 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2632 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2633 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2634 2635 CONFIG_SPL_TARGET 2636 Final target image containing SPL and payload. Some SPLs 2637 use an arch-specific makefile fragment instead, for 2638 example if more than one image needs to be produced. 2639 2640 CONFIG_SPL_FIT_PRINT 2641 Printing information about a FIT image adds quite a bit of 2642 code to SPL. So this is normally disabled in SPL. Use this 2643 option to re-enable it. This will affect the output of the 2644 bootm command when booting a FIT image. 2645 2646- TPL framework 2647 CONFIG_TPL 2648 Enable building of TPL globally. 2649 2650 CONFIG_TPL_PAD_TO 2651 Image offset to which the TPL should be padded before appending 2652 the TPL payload. By default, this is defined as 2653 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2654 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2655 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2656 2657- Interrupt support (PPC): 2658 2659 There are common interrupt_init() and timer_interrupt() 2660 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2661 for CPU specific initialization. interrupt_init_cpu() 2662 should set decrementer_count to appropriate value. If 2663 CPU resets decrementer automatically after interrupt 2664 (ppc4xx) it should set decrementer_count to zero. 2665 timer_interrupt() calls timer_interrupt_cpu() for CPU 2666 specific handling. If board has watchdog / status_led 2667 / other_activity_monitor it works automatically from 2668 general timer_interrupt(). 2669 2670 2671Board initialization settings: 2672------------------------------ 2673 2674During Initialization u-boot calls a number of board specific functions 2675to allow the preparation of board specific prerequisites, e.g. pin setup 2676before drivers are initialized. To enable these callbacks the 2677following configuration macros have to be defined. Currently this is 2678architecture specific, so please check arch/your_architecture/lib/board.c 2679typically in board_init_f() and board_init_r(). 2680 2681- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2682- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2683- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2684- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2685 2686Configuration Settings: 2687----------------------- 2688 2689- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2690 Optionally it can be defined to support 64-bit memory commands. 2691 2692- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2693 undefine this when you're short of memory. 2694 2695- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2696 width of the commands listed in the 'help' command output. 2697 2698- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2699 prompt for user input. 2700 2701- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2702 2703- CONFIG_SYS_PBSIZE: Buffer size for Console output 2704 2705- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2706 2707- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2708 the application (usually a Linux kernel) when it is 2709 booted 2710 2711- CONFIG_SYS_BAUDRATE_TABLE: 2712 List of legal baudrate settings for this board. 2713 2714- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: 2715 Begin and End addresses of the area used by the 2716 simple memory test. 2717 2718- CONFIG_SYS_MEMTEST_SCRATCH: 2719 Scratch address used by the alternate memory test 2720 You only need to set this if address zero isn't writeable 2721 2722- CONFIG_SYS_MEM_RESERVE_SECURE 2723 Only implemented for ARMv8 for now. 2724 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2725 is substracted from total RAM and won't be reported to OS. 2726 This memory can be used as secure memory. A variable 2727 gd->arch.secure_ram is used to track the location. In systems 2728 the RAM base is not zero, or RAM is divided into banks, 2729 this variable needs to be recalcuated to get the address. 2730 2731- CONFIG_SYS_MEM_TOP_HIDE: 2732 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2733 this specified memory area will get subtracted from the top 2734 (end) of RAM and won't get "touched" at all by U-Boot. By 2735 fixing up gd->ram_size the Linux kernel should gets passed 2736 the now "corrected" memory size and won't touch it either. 2737 This should work for arch/ppc and arch/powerpc. Only Linux 2738 board ports in arch/powerpc with bootwrapper support that 2739 recalculate the memory size from the SDRAM controller setup 2740 will have to get fixed in Linux additionally. 2741 2742 This option can be used as a workaround for the 440EPx/GRx 2743 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2744 be touched. 2745 2746 WARNING: Please make sure that this value is a multiple of 2747 the Linux page size (normally 4k). If this is not the case, 2748 then the end address of the Linux memory will be located at a 2749 non page size aligned address and this could cause major 2750 problems. 2751 2752- CONFIG_SYS_LOADS_BAUD_CHANGE: 2753 Enable temporary baudrate change while serial download 2754 2755- CONFIG_SYS_SDRAM_BASE: 2756 Physical start address of SDRAM. _Must_ be 0 here. 2757 2758- CONFIG_SYS_FLASH_BASE: 2759 Physical start address of Flash memory. 2760 2761- CONFIG_SYS_MONITOR_BASE: 2762 Physical start address of boot monitor code (set by 2763 make config files to be same as the text base address 2764 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2765 CONFIG_SYS_FLASH_BASE when booting from flash. 2766 2767- CONFIG_SYS_MONITOR_LEN: 2768 Size of memory reserved for monitor code, used to 2769 determine _at_compile_time_ (!) if the environment is 2770 embedded within the U-Boot image, or in a separate 2771 flash sector. 2772 2773- CONFIG_SYS_MALLOC_LEN: 2774 Size of DRAM reserved for malloc() use. 2775 2776- CONFIG_SYS_MALLOC_F_LEN 2777 Size of the malloc() pool for use before relocation. If 2778 this is defined, then a very simple malloc() implementation 2779 will become available before relocation. The address is just 2780 below the global data, and the stack is moved down to make 2781 space. 2782 2783 This feature allocates regions with increasing addresses 2784 within the region. calloc() is supported, but realloc() 2785 is not available. free() is supported but does nothing. 2786 The memory will be freed (or in fact just forgotten) when 2787 U-Boot relocates itself. 2788 2789- CONFIG_SYS_MALLOC_SIMPLE 2790 Provides a simple and small malloc() and calloc() for those 2791 boards which do not use the full malloc in SPL (which is 2792 enabled with CONFIG_SYS_SPL_MALLOC_START). 2793 2794- CONFIG_SYS_NONCACHED_MEMORY: 2795 Size of non-cached memory area. This area of memory will be 2796 typically located right below the malloc() area and mapped 2797 uncached in the MMU. This is useful for drivers that would 2798 otherwise require a lot of explicit cache maintenance. For 2799 some drivers it's also impossible to properly maintain the 2800 cache. For example if the regions that need to be flushed 2801 are not a multiple of the cache-line size, *and* padding 2802 cannot be allocated between the regions to align them (i.e. 2803 if the HW requires a contiguous array of regions, and the 2804 size of each region is not cache-aligned), then a flush of 2805 one region may result in overwriting data that hardware has 2806 written to another region in the same cache-line. This can 2807 happen for example in network drivers where descriptors for 2808 buffers are typically smaller than the CPU cache-line (e.g. 2809 16 bytes vs. 32 or 64 bytes). 2810 2811 Non-cached memory is only supported on 32-bit ARM at present. 2812 2813- CONFIG_SYS_BOOTM_LEN: 2814 Normally compressed uImages are limited to an 2815 uncompressed size of 8 MBytes. If this is not enough, 2816 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2817 to adjust this setting to your needs. 2818 2819- CONFIG_SYS_BOOTMAPSZ: 2820 Maximum size of memory mapped by the startup code of 2821 the Linux kernel; all data that must be processed by 2822 the Linux kernel (bd_info, boot arguments, FDT blob if 2823 used) must be put below this limit, unless "bootm_low" 2824 environment variable is defined and non-zero. In such case 2825 all data for the Linux kernel must be between "bootm_low" 2826 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2827 variable "bootm_mapsize" will override the value of 2828 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2829 then the value in "bootm_size" will be used instead. 2830 2831- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2832 Enable initrd_high functionality. If defined then the 2833 initrd_high feature is enabled and the bootm ramdisk subcommand 2834 is enabled. 2835 2836- CONFIG_SYS_BOOT_GET_CMDLINE: 2837 Enables allocating and saving kernel cmdline in space between 2838 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2839 2840- CONFIG_SYS_BOOT_GET_KBD: 2841 Enables allocating and saving a kernel copy of the bd_info in 2842 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2843 2844- CONFIG_SYS_MAX_FLASH_BANKS: 2845 Max number of Flash memory banks 2846 2847- CONFIG_SYS_MAX_FLASH_SECT: 2848 Max number of sectors on a Flash chip 2849 2850- CONFIG_SYS_FLASH_ERASE_TOUT: 2851 Timeout for Flash erase operations (in ms) 2852 2853- CONFIG_SYS_FLASH_WRITE_TOUT: 2854 Timeout for Flash write operations (in ms) 2855 2856- CONFIG_SYS_FLASH_LOCK_TOUT 2857 Timeout for Flash set sector lock bit operation (in ms) 2858 2859- CONFIG_SYS_FLASH_UNLOCK_TOUT 2860 Timeout for Flash clear lock bits operation (in ms) 2861 2862- CONFIG_SYS_FLASH_PROTECTION 2863 If defined, hardware flash sectors protection is used 2864 instead of U-Boot software protection. 2865 2866- CONFIG_SYS_DIRECT_FLASH_TFTP: 2867 2868 Enable TFTP transfers directly to flash memory; 2869 without this option such a download has to be 2870 performed in two steps: (1) download to RAM, and (2) 2871 copy from RAM to flash. 2872 2873 The two-step approach is usually more reliable, since 2874 you can check if the download worked before you erase 2875 the flash, but in some situations (when system RAM is 2876 too limited to allow for a temporary copy of the 2877 downloaded image) this option may be very useful. 2878 2879- CONFIG_SYS_FLASH_CFI: 2880 Define if the flash driver uses extra elements in the 2881 common flash structure for storing flash geometry. 2882 2883- CONFIG_FLASH_CFI_DRIVER 2884 This option also enables the building of the cfi_flash driver 2885 in the drivers directory 2886 2887- CONFIG_FLASH_CFI_MTD 2888 This option enables the building of the cfi_mtd driver 2889 in the drivers directory. The driver exports CFI flash 2890 to the MTD layer. 2891 2892- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2893 Use buffered writes to flash. 2894 2895- CONFIG_FLASH_SPANSION_S29WS_N 2896 s29ws-n MirrorBit flash has non-standard addresses for buffered 2897 write commands. 2898 2899- CONFIG_SYS_FLASH_QUIET_TEST 2900 If this option is defined, the common CFI flash doesn't 2901 print it's warning upon not recognized FLASH banks. This 2902 is useful, if some of the configured banks are only 2903 optionally available. 2904 2905- CONFIG_FLASH_SHOW_PROGRESS 2906 If defined (must be an integer), print out countdown 2907 digits and dots. Recommended value: 45 (9..1) for 80 2908 column displays, 15 (3..1) for 40 column displays. 2909 2910- CONFIG_FLASH_VERIFY 2911 If defined, the content of the flash (destination) is compared 2912 against the source after the write operation. An error message 2913 will be printed when the contents are not identical. 2914 Please note that this option is useless in nearly all cases, 2915 since such flash programming errors usually are detected earlier 2916 while unprotecting/erasing/programming. Please only enable 2917 this option if you really know what you are doing. 2918 2919- CONFIG_SYS_RX_ETH_BUFFER: 2920 Defines the number of Ethernet receive buffers. On some 2921 Ethernet controllers it is recommended to set this value 2922 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2923 buffers can be full shortly after enabling the interface 2924 on high Ethernet traffic. 2925 Defaults to 4 if not defined. 2926 2927- CONFIG_ENV_MAX_ENTRIES 2928 2929 Maximum number of entries in the hash table that is used 2930 internally to store the environment settings. The default 2931 setting is supposed to be generous and should work in most 2932 cases. This setting can be used to tune behaviour; see 2933 lib/hashtable.c for details. 2934 2935- CONFIG_ENV_FLAGS_LIST_DEFAULT 2936- CONFIG_ENV_FLAGS_LIST_STATIC 2937 Enable validation of the values given to environment variables when 2938 calling env set. Variables can be restricted to only decimal, 2939 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2940 the variables can also be restricted to IP address or MAC address. 2941 2942 The format of the list is: 2943 type_attribute = [s|d|x|b|i|m] 2944 access_attribute = [a|r|o|c] 2945 attributes = type_attribute[access_attribute] 2946 entry = variable_name[:attributes] 2947 list = entry[,list] 2948 2949 The type attributes are: 2950 s - String (default) 2951 d - Decimal 2952 x - Hexadecimal 2953 b - Boolean ([1yYtT|0nNfF]) 2954 i - IP address 2955 m - MAC address 2956 2957 The access attributes are: 2958 a - Any (default) 2959 r - Read-only 2960 o - Write-once 2961 c - Change-default 2962 2963 - CONFIG_ENV_FLAGS_LIST_DEFAULT 2964 Define this to a list (string) to define the ".flags" 2965 environment variable in the default or embedded environment. 2966 2967 - CONFIG_ENV_FLAGS_LIST_STATIC 2968 Define this to a list (string) to define validation that 2969 should be done if an entry is not found in the ".flags" 2970 environment variable. To override a setting in the static 2971 list, simply add an entry for the same variable name to the 2972 ".flags" variable. 2973 2974 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 2975 regular expression. This allows multiple variables to define the same 2976 flags without explicitly listing them for each variable. 2977 2978- CONFIG_ENV_ACCESS_IGNORE_FORCE 2979 If defined, don't allow the -f switch to env set override variable 2980 access flags. 2981 2982The following definitions that deal with the placement and management 2983of environment data (variable area); in general, we support the 2984following configurations: 2985 2986- CONFIG_BUILD_ENVCRC: 2987 2988 Builds up envcrc with the target environment so that external utils 2989 may easily extract it and embed it in final U-Boot images. 2990 2991BE CAREFUL! The first access to the environment happens quite early 2992in U-Boot initialization (when we try to get the setting of for the 2993console baudrate). You *MUST* have mapped your NVRAM area then, or 2994U-Boot will hang. 2995 2996Please note that even with NVRAM we still use a copy of the 2997environment in RAM: we could work on NVRAM directly, but we want to 2998keep settings there always unmodified except somebody uses "saveenv" 2999to save the current settings. 3000 3001BE CAREFUL! For some special cases, the local device can not use 3002"saveenv" command. For example, the local device will get the 3003environment stored in a remote NOR flash by SRIO or PCIE link, 3004but it can not erase, write this NOR flash by SRIO or PCIE interface. 3005 3006- CONFIG_NAND_ENV_DST 3007 3008 Defines address in RAM to which the nand_spl code should copy the 3009 environment. If redundant environment is used, it will be copied to 3010 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 3011 3012Please note that the environment is read-only until the monitor 3013has been relocated to RAM and a RAM copy of the environment has been 3014created; also, when using EEPROM you will have to use env_get_f() 3015until then to read environment variables. 3016 3017The environment is protected by a CRC32 checksum. Before the monitor 3018is relocated into RAM, as a result of a bad CRC you will be working 3019with the compiled-in default environment - *silently*!!! [This is 3020necessary, because the first environment variable we need is the 3021"baudrate" setting for the console - if we have a bad CRC, we don't 3022have any device yet where we could complain.] 3023 3024Note: once the monitor has been relocated, then it will complain if 3025the default environment is used; a new CRC is computed as soon as you 3026use the "saveenv" command to store a valid environment. 3027 3028- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 3029 Echo the inverted Ethernet link state to the fault LED. 3030 3031 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 3032 also needs to be defined. 3033 3034- CONFIG_SYS_FAULT_MII_ADDR: 3035 MII address of the PHY to check for the Ethernet link state. 3036 3037- CONFIG_NS16550_MIN_FUNCTIONS: 3038 Define this if you desire to only have use of the NS16550_init 3039 and NS16550_putc functions for the serial driver located at 3040 drivers/serial/ns16550.c. This option is useful for saving 3041 space for already greatly restricted images, including but not 3042 limited to NAND_SPL configurations. 3043 3044- CONFIG_DISPLAY_BOARDINFO 3045 Display information about the board that U-Boot is running on 3046 when U-Boot starts up. The board function checkboard() is called 3047 to do this. 3048 3049- CONFIG_DISPLAY_BOARDINFO_LATE 3050 Similar to the previous option, but display this information 3051 later, once stdio is running and output goes to the LCD, if 3052 present. 3053 3054- CONFIG_BOARD_SIZE_LIMIT: 3055 Maximum size of the U-Boot image. When defined, the 3056 build system checks that the actual size does not 3057 exceed it. 3058 3059Low Level (hardware related) configuration options: 3060--------------------------------------------------- 3061 3062- CONFIG_SYS_CACHELINE_SIZE: 3063 Cache Line Size of the CPU. 3064 3065- CONFIG_SYS_CCSRBAR_DEFAULT: 3066 Default (power-on reset) physical address of CCSR on Freescale 3067 PowerPC SOCs. 3068 3069- CONFIG_SYS_CCSRBAR: 3070 Virtual address of CCSR. On a 32-bit build, this is typically 3071 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 3072 3073- CONFIG_SYS_CCSRBAR_PHYS: 3074 Physical address of CCSR. CCSR can be relocated to a new 3075 physical address, if desired. In this case, this macro should 3076 be set to that address. Otherwise, it should be set to the 3077 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 3078 is typically relocated on 36-bit builds. It is recommended 3079 that this macro be defined via the _HIGH and _LOW macros: 3080 3081 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 3082 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 3083 3084- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 3085 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 3086 either 0 (32-bit build) or 0xF (36-bit build). This macro is 3087 used in assembly code, so it must not contain typecasts or 3088 integer size suffixes (e.g. "ULL"). 3089 3090- CONFIG_SYS_CCSRBAR_PHYS_LOW: 3091 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 3092 used in assembly code, so it must not contain typecasts or 3093 integer size suffixes (e.g. "ULL"). 3094 3095- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 3096 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 3097 forced to a value that ensures that CCSR is not relocated. 3098 3099- Floppy Disk Support: 3100 CONFIG_SYS_FDC_DRIVE_NUMBER 3101 3102 the default drive number (default value 0) 3103 3104 CONFIG_SYS_ISA_IO_STRIDE 3105 3106 defines the spacing between FDC chipset registers 3107 (default value 1) 3108 3109 CONFIG_SYS_ISA_IO_OFFSET 3110 3111 defines the offset of register from address. It 3112 depends on which part of the data bus is connected to 3113 the FDC chipset. (default value 0) 3114 3115 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and 3116 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their 3117 default value. 3118 3119 if CONFIG_SYS_FDC_HW_INIT is defined, then the function 3120 fdc_hw_init() is called at the beginning of the FDC 3121 setup. fdc_hw_init() must be provided by the board 3122 source code. It is used to make hardware-dependent 3123 initializations. 3124 3125- CONFIG_IDE_AHB: 3126 Most IDE controllers were designed to be connected with PCI 3127 interface. Only few of them were designed for AHB interface. 3128 When software is doing ATA command and data transfer to 3129 IDE devices through IDE-AHB controller, some additional 3130 registers accessing to these kind of IDE-AHB controller 3131 is required. 3132 3133- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 3134 DO NOT CHANGE unless you know exactly what you're 3135 doing! (11-4) [MPC8xx systems only] 3136 3137- CONFIG_SYS_INIT_RAM_ADDR: 3138 3139 Start address of memory area that can be used for 3140 initial data and stack; please note that this must be 3141 writable memory that is working WITHOUT special 3142 initialization, i. e. you CANNOT use normal RAM which 3143 will become available only after programming the 3144 memory controller and running certain initialization 3145 sequences. 3146 3147 U-Boot uses the following memory types: 3148 - MPC8xx: IMMR (internal memory of the CPU) 3149 3150- CONFIG_SYS_GBL_DATA_OFFSET: 3151 3152 Offset of the initial data structure in the memory 3153 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 3154 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 3155 data is located at the end of the available space 3156 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 3157 GENERATED_GBL_DATA_SIZE), and the initial stack is just 3158 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 3159 CONFIG_SYS_GBL_DATA_OFFSET) downward. 3160 3161 Note: 3162 On the MPC824X (or other systems that use the data 3163 cache for initial memory) the address chosen for 3164 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 3165 point to an otherwise UNUSED address space between 3166 the top of RAM and the start of the PCI space. 3167 3168- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 3169 3170- CONFIG_SYS_OR_TIMING_SDRAM: 3171 SDRAM timing 3172 3173- CONFIG_SYS_MAMR_PTA: 3174 periodic timer for refresh 3175 3176- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 3177 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 3178 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 3179 CONFIG_SYS_BR1_PRELIM: 3180 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 3181 3182- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 3183 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 3184 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 3185 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 3186 3187- CONFIG_PCI_ENUM_ONLY 3188 Only scan through and get the devices on the buses. 3189 Don't do any setup work, presumably because someone or 3190 something has already done it, and we don't need to do it 3191 a second time. Useful for platforms that are pre-booted 3192 by coreboot or similar. 3193 3194- CONFIG_PCI_INDIRECT_BRIDGE: 3195 Enable support for indirect PCI bridges. 3196 3197- CONFIG_SYS_SRIO: 3198 Chip has SRIO or not 3199 3200- CONFIG_SRIO1: 3201 Board has SRIO 1 port available 3202 3203- CONFIG_SRIO2: 3204 Board has SRIO 2 port available 3205 3206- CONFIG_SRIO_PCIE_BOOT_MASTER 3207 Board can support master function for Boot from SRIO and PCIE 3208 3209- CONFIG_SYS_SRIOn_MEM_VIRT: 3210 Virtual Address of SRIO port 'n' memory region 3211 3212- CONFIG_SYS_SRIOn_MEM_PHYS: 3213 Physical Address of SRIO port 'n' memory region 3214 3215- CONFIG_SYS_SRIOn_MEM_SIZE: 3216 Size of SRIO port 'n' memory region 3217 3218- CONFIG_SYS_NAND_BUSWIDTH_16BIT 3219 Defined to tell the NAND controller that the NAND chip is using 3220 a 16 bit bus. 3221 Not all NAND drivers use this symbol. 3222 Example of drivers that use it: 3223 - drivers/mtd/nand/raw/ndfc.c 3224 - drivers/mtd/nand/raw/mxc_nand.c 3225 3226- CONFIG_SYS_NDFC_EBC0_CFG 3227 Sets the EBC0_CFG register for the NDFC. If not defined 3228 a default value will be used. 3229 3230- CONFIG_SPD_EEPROM 3231 Get DDR timing information from an I2C EEPROM. Common 3232 with pluggable memory modules such as SODIMMs 3233 3234 SPD_EEPROM_ADDRESS 3235 I2C address of the SPD EEPROM 3236 3237- CONFIG_SYS_SPD_BUS_NUM 3238 If SPD EEPROM is on an I2C bus other than the first 3239 one, specify here. Note that the value must resolve 3240 to something your driver can deal with. 3241 3242- CONFIG_SYS_DDR_RAW_TIMING 3243 Get DDR timing information from other than SPD. Common with 3244 soldered DDR chips onboard without SPD. DDR raw timing 3245 parameters are extracted from datasheet and hard-coded into 3246 header files or board specific files. 3247 3248- CONFIG_FSL_DDR_INTERACTIVE 3249 Enable interactive DDR debugging. See doc/README.fsl-ddr. 3250 3251- CONFIG_FSL_DDR_SYNC_REFRESH 3252 Enable sync of refresh for multiple controllers. 3253 3254- CONFIG_FSL_DDR_BIST 3255 Enable built-in memory test for Freescale DDR controllers. 3256 3257- CONFIG_SYS_83XX_DDR_USES_CS0 3258 Only for 83xx systems. If specified, then DDR should 3259 be configured using CS0 and CS1 instead of CS2 and CS3. 3260 3261- CONFIG_RMII 3262 Enable RMII mode for all FECs. 3263 Note that this is a global option, we can't 3264 have one FEC in standard MII mode and another in RMII mode. 3265 3266- CONFIG_CRC32_VERIFY 3267 Add a verify option to the crc32 command. 3268 The syntax is: 3269 3270 => crc32 -v <address> <count> <crc32> 3271 3272 Where address/count indicate a memory area 3273 and crc32 is the correct crc32 which the 3274 area should have. 3275 3276- CONFIG_LOOPW 3277 Add the "loopw" memory command. This only takes effect if 3278 the memory commands are activated globally (CONFIG_CMD_MEMORY). 3279 3280- CONFIG_MX_CYCLIC 3281 Add the "mdc" and "mwc" memory commands. These are cyclic 3282 "md/mw" commands. 3283 Examples: 3284 3285 => mdc.b 10 4 500 3286 This command will print 4 bytes (10,11,12,13) each 500 ms. 3287 3288 => mwc.l 100 12345678 10 3289 This command will write 12345678 to address 100 all 10 ms. 3290 3291 This only takes effect if the memory commands are activated 3292 globally (CONFIG_CMD_MEMORY). 3293 3294- CONFIG_SKIP_LOWLEVEL_INIT 3295 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 3296 low level initializations (like setting up the memory 3297 controller) are omitted and/or U-Boot does not 3298 relocate itself into RAM. 3299 3300 Normally this variable MUST NOT be defined. The only 3301 exception is when U-Boot is loaded (to RAM) by some 3302 other boot loader or by a debugger which performs 3303 these initializations itself. 3304 3305- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 3306 [ARM926EJ-S only] This allows just the call to lowlevel_init() 3307 to be skipped. The normal CP15 init (such as enabling the 3308 instruction cache) is still performed. 3309 3310- CONFIG_SPL_BUILD 3311 Modifies the behaviour of start.S when compiling a loader 3312 that is executed before the actual U-Boot. E.g. when 3313 compiling a NAND SPL. 3314 3315- CONFIG_TPL_BUILD 3316 Modifies the behaviour of start.S when compiling a loader 3317 that is executed after the SPL and before the actual U-Boot. 3318 It is loaded by the SPL. 3319 3320- CONFIG_SYS_MPC85XX_NO_RESETVEC 3321 Only for 85xx systems. If this variable is specified, the section 3322 .resetvec is not kept and the section .bootpg is placed in the 3323 previous 4k of the .text section. 3324 3325- CONFIG_ARCH_MAP_SYSMEM 3326 Generally U-Boot (and in particular the md command) uses 3327 effective address. It is therefore not necessary to regard 3328 U-Boot address as virtual addresses that need to be translated 3329 to physical addresses. However, sandbox requires this, since 3330 it maintains its own little RAM buffer which contains all 3331 addressable memory. This option causes some memory accesses 3332 to be mapped through map_sysmem() / unmap_sysmem(). 3333 3334- CONFIG_X86_RESET_VECTOR 3335 If defined, the x86 reset vector code is included. This is not 3336 needed when U-Boot is running from Coreboot. 3337 3338- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 3339 Option to disable subpage write in NAND driver 3340 driver that uses this: 3341 drivers/mtd/nand/raw/davinci_nand.c 3342 3343Freescale QE/FMAN Firmware Support: 3344----------------------------------- 3345 3346The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 3347loading of "firmware", which is encoded in the QE firmware binary format. 3348This firmware often needs to be loaded during U-Boot booting, so macros 3349are used to identify the storage device (NOR flash, SPI, etc) and the address 3350within that device. 3351 3352- CONFIG_SYS_FMAN_FW_ADDR 3353 The address in the storage device where the FMAN microcode is located. The 3354 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3355 is also specified. 3356 3357- CONFIG_SYS_QE_FW_ADDR 3358 The address in the storage device where the QE microcode is located. The 3359 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3360 is also specified. 3361 3362- CONFIG_SYS_QE_FMAN_FW_LENGTH 3363 The maximum possible size of the firmware. The firmware binary format 3364 has a field that specifies the actual size of the firmware, but it 3365 might not be possible to read any part of the firmware unless some 3366 local storage is allocated to hold the entire firmware first. 3367 3368- CONFIG_SYS_QE_FMAN_FW_IN_NOR 3369 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 3370 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 3371 virtual address in NOR flash. 3372 3373- CONFIG_SYS_QE_FMAN_FW_IN_NAND 3374 Specifies that QE/FMAN firmware is located in NAND flash. 3375 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 3376 3377- CONFIG_SYS_QE_FMAN_FW_IN_MMC 3378 Specifies that QE/FMAN firmware is located on the primary SD/MMC 3379 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 3380 3381- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 3382 Specifies that QE/FMAN firmware is located in the remote (master) 3383 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 3384 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 3385 window->master inbound window->master LAW->the ucode address in 3386 master's memory space. 3387 3388Freescale Layerscape Management Complex Firmware Support: 3389--------------------------------------------------------- 3390The Freescale Layerscape Management Complex (MC) supports the loading of 3391"firmware". 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_FSL_MC_ENET 3397 Enable the MC driver for Layerscape SoCs. 3398 3399Freescale Layerscape Debug Server Support: 3400------------------------------------------- 3401The Freescale Layerscape Debug Server Support supports the loading of 3402"Debug Server firmware" and triggering SP boot-rom. 3403This firmware often needs to be loaded during U-Boot booting. 3404 3405- CONFIG_SYS_MC_RSV_MEM_ALIGN 3406 Define alignment of reserved memory MC requires 3407 3408Reproducible builds 3409------------------- 3410 3411In order to achieve reproducible builds, timestamps used in the U-Boot build 3412process have to be set to a fixed value. 3413 3414This is done using the SOURCE_DATE_EPOCH environment variable. 3415SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3416option for U-Boot or an environment variable in U-Boot. 3417 3418SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3419 3420Building the Software: 3421====================== 3422 3423Building U-Boot has been tested in several native build environments 3424and in many different cross environments. Of course we cannot support 3425all possibly existing versions of cross development tools in all 3426(potentially obsolete) versions. In case of tool chain problems we 3427recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) 3428which is extensively used to build and test U-Boot. 3429 3430If you are not using a native environment, it is assumed that you 3431have GNU cross compiling tools available in your path. In this case, 3432you must set the environment variable CROSS_COMPILE in your shell. 3433Note that no changes to the Makefile or any other source files are 3434necessary. For example using the ELDK on a 4xx CPU, please enter: 3435 3436 $ CROSS_COMPILE=ppc_4xx- 3437 $ export CROSS_COMPILE 3438 3439Note: If you wish to generate Windows versions of the utilities in 3440 the tools directory you can use the MinGW toolchain 3441 (http://www.mingw.org). Set your HOST tools to the MinGW 3442 toolchain and execute 'make tools'. For example: 3443 3444 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools 3445 3446 Binaries such as tools/mkimage.exe will be created which can 3447 be executed on computers running Windows. 3448 3449U-Boot is intended to be simple to build. After installing the 3450sources you must configure U-Boot for one specific board type. This 3451is done by typing: 3452 3453 make NAME_defconfig 3454 3455where "NAME_defconfig" is the name of one of the existing configu- 3456rations; see boards.cfg for supported names. 3457 3458Note: for some board special configuration names may exist; check if 3459 additional information is available from the board vendor; for 3460 instance, the TQM823L systems are available without (standard) 3461 or with LCD support. You can select such additional "features" 3462 when choosing the configuration, i. e. 3463 3464 make TQM823L_defconfig 3465 - will configure for a plain TQM823L, i. e. no LCD support 3466 3467 make TQM823L_LCD_defconfig 3468 - will configure for a TQM823L with U-Boot console on LCD 3469 3470 etc. 3471 3472 3473Finally, type "make all", and you should get some working U-Boot 3474images ready for download to / installation on your system: 3475 3476- "u-boot.bin" is a raw binary image 3477- "u-boot" is an image in ELF binary format 3478- "u-boot.srec" is in Motorola S-Record format 3479 3480By default the build is performed locally and the objects are saved 3481in the source directory. One of the two methods can be used to change 3482this behavior and build U-Boot to some external directory: 3483 34841. Add O= to the make command line invocations: 3485 3486 make O=/tmp/build distclean 3487 make O=/tmp/build NAME_defconfig 3488 make O=/tmp/build all 3489 34902. Set environment variable KBUILD_OUTPUT to point to the desired location: 3491 3492 export KBUILD_OUTPUT=/tmp/build 3493 make distclean 3494 make NAME_defconfig 3495 make all 3496 3497Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3498variable. 3499 3500User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3501setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3502For example to treat all compiler warnings as errors: 3503 3504 make KCFLAGS=-Werror 3505 3506Please be aware that the Makefiles assume you are using GNU make, so 3507for instance on NetBSD you might need to use "gmake" instead of 3508native "make". 3509 3510 3511If the system board that you have is not listed, then you will need 3512to port U-Boot to your hardware platform. To do this, follow these 3513steps: 3514 35151. Create a new directory to hold your board specific code. Add any 3516 files you need. In your board directory, you will need at least 3517 the "Makefile" and a "<board>.c". 35182. Create a new configuration file "include/configs/<board>.h" for 3519 your board. 35203. If you're porting U-Boot to a new CPU, then also create a new 3521 directory to hold your CPU specific code. Add any files you need. 35224. Run "make <board>_defconfig" with your new name. 35235. Type "make", and you should get a working "u-boot.srec" file 3524 to be installed on your target system. 35256. Debug and solve any problems that might arise. 3526 [Of course, this last step is much harder than it sounds.] 3527 3528 3529Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3530============================================================== 3531 3532If you have modified U-Boot sources (for instance added a new board 3533or support for new devices, a new CPU, etc.) you are expected to 3534provide feedback to the other developers. The feedback normally takes 3535the form of a "patch", i. e. a context diff against a certain (latest 3536official or latest in the git repository) version of U-Boot sources. 3537 3538But before you submit such a patch, please verify that your modifi- 3539cation did not break existing code. At least make sure that *ALL* of 3540the supported boards compile WITHOUT ANY compiler warnings. To do so, 3541just run the buildman script (tools/buildman/buildman), which will 3542configure and build U-Boot for ALL supported system. Be warned, this 3543will take a while. Please see the buildman README, or run 'buildman -H' 3544for documentation. 3545 3546 3547See also "U-Boot Porting Guide" below. 3548 3549 3550Monitor Commands - Overview: 3551============================ 3552 3553go - start application at address 'addr' 3554run - run commands in an environment variable 3555bootm - boot application image from memory 3556bootp - boot image via network using BootP/TFTP protocol 3557bootz - boot zImage from memory 3558tftpboot- boot image via network using TFTP protocol 3559 and env variables "ipaddr" and "serverip" 3560 (and eventually "gatewayip") 3561tftpput - upload a file via network using TFTP protocol 3562rarpboot- boot image via network using RARP/TFTP protocol 3563diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3564loads - load S-Record file over serial line 3565loadb - load binary file over serial line (kermit mode) 3566md - memory display 3567mm - memory modify (auto-incrementing) 3568nm - memory modify (constant address) 3569mw - memory write (fill) 3570cp - memory copy 3571cmp - memory compare 3572crc32 - checksum calculation 3573i2c - I2C sub-system 3574sspi - SPI utility commands 3575base - print or set address offset 3576printenv- print environment variables 3577setenv - set environment variables 3578saveenv - save environment variables to persistent storage 3579protect - enable or disable FLASH write protection 3580erase - erase FLASH memory 3581flinfo - print FLASH memory information 3582nand - NAND memory operations (see doc/README.nand) 3583bdinfo - print Board Info structure 3584iminfo - print header information for application image 3585coninfo - print console devices and informations 3586ide - IDE sub-system 3587loop - infinite loop on address range 3588loopw - infinite write loop on address range 3589mtest - simple RAM test 3590icache - enable or disable instruction cache 3591dcache - enable or disable data cache 3592reset - Perform RESET of the CPU 3593echo - echo args to console 3594version - print monitor version 3595help - print online help 3596? - alias for 'help' 3597 3598 3599Monitor Commands - Detailed Description: 3600======================================== 3601 3602TODO. 3603 3604For now: just type "help <command>". 3605 3606 3607Environment Variables: 3608====================== 3609 3610U-Boot supports user configuration using Environment Variables which 3611can be made persistent by saving to Flash memory. 3612 3613Environment Variables are set using "setenv", printed using 3614"printenv", and saved to Flash using "saveenv". Using "setenv" 3615without a value can be used to delete a variable from the 3616environment. As long as you don't save the environment you are 3617working with an in-memory copy. In case the Flash area containing the 3618environment is erased by accident, a default environment is provided. 3619 3620Some configuration options can be set using Environment Variables. 3621 3622List of environment variables (most likely not complete): 3623 3624 baudrate - see CONFIG_BAUDRATE 3625 3626 bootdelay - see CONFIG_BOOTDELAY 3627 3628 bootcmd - see CONFIG_BOOTCOMMAND 3629 3630 bootargs - Boot arguments when booting an RTOS image 3631 3632 bootfile - Name of the image to load with TFTP 3633 3634 bootm_low - Memory range available for image processing in the bootm 3635 command can be restricted. This variable is given as 3636 a hexadecimal number and defines lowest address allowed 3637 for use by the bootm command. See also "bootm_size" 3638 environment variable. Address defined by "bootm_low" is 3639 also the base of the initial memory mapping for the Linux 3640 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3641 bootm_mapsize. 3642 3643 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3644 This variable is given as a hexadecimal number and it 3645 defines the size of the memory region starting at base 3646 address bootm_low that is accessible by the Linux kernel 3647 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3648 as the default value if it is defined, and bootm_size is 3649 used otherwise. 3650 3651 bootm_size - Memory range available for image processing in the bootm 3652 command can be restricted. This variable is given as 3653 a hexadecimal number and defines the size of the region 3654 allowed for use by the bootm command. See also "bootm_low" 3655 environment variable. 3656 3657 updatefile - Location of the software update file on a TFTP server, used 3658 by the automatic software update feature. Please refer to 3659 documentation in doc/README.update for more details. 3660 3661 autoload - if set to "no" (any string beginning with 'n'), 3662 "bootp" will just load perform a lookup of the 3663 configuration from the BOOTP server, but not try to 3664 load any image using TFTP 3665 3666 autostart - if set to "yes", an image loaded using the "bootp", 3667 "rarpboot", "tftpboot" or "diskboot" commands will 3668 be automatically started (by internally calling 3669 "bootm") 3670 3671 If set to "no", a standalone image passed to the 3672 "bootm" command will be copied to the load address 3673 (and eventually uncompressed), but NOT be started. 3674 This can be used to load and uncompress arbitrary 3675 data. 3676 3677 fdt_high - if set this restricts the maximum address that the 3678 flattened device tree will be copied into upon boot. 3679 For example, if you have a system with 1 GB memory 3680 at physical address 0x10000000, while Linux kernel 3681 only recognizes the first 704 MB as low memory, you 3682 may need to set fdt_high as 0x3C000000 to have the 3683 device tree blob be copied to the maximum address 3684 of the 704 MB low memory, so that Linux kernel can 3685 access it during the boot procedure. 3686 3687 If this is set to the special value 0xFFFFFFFF then 3688 the fdt will not be copied at all on boot. For this 3689 to work it must reside in writable memory, have 3690 sufficient padding on the end of it for u-boot to 3691 add the information it needs into it, and the memory 3692 must be accessible by the kernel. 3693 3694 fdtcontroladdr- if set this is the address of the control flattened 3695 device tree used by U-Boot when CONFIG_OF_CONTROL is 3696 defined. 3697 3698 i2cfast - (PPC405GP|PPC405EP only) 3699 if set to 'y' configures Linux I2C driver for fast 3700 mode (400kHZ). This environment variable is used in 3701 initialization code. So, for changes to be effective 3702 it must be saved and board must be reset. 3703 3704 initrd_high - restrict positioning of initrd images: 3705 If this variable is not set, initrd images will be 3706 copied to the highest possible address in RAM; this 3707 is usually what you want since it allows for 3708 maximum initrd size. If for some reason you want to 3709 make sure that the initrd image is loaded below the 3710 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3711 variable to a value of "no" or "off" or "0". 3712 Alternatively, you can set it to a maximum upper 3713 address to use (U-Boot will still check that it 3714 does not overwrite the U-Boot stack and data). 3715 3716 For instance, when you have a system with 16 MB 3717 RAM, and want to reserve 4 MB from use by Linux, 3718 you can do this by adding "mem=12M" to the value of 3719 the "bootargs" variable. However, now you must make 3720 sure that the initrd image is placed in the first 3721 12 MB as well - this can be done with 3722 3723 setenv initrd_high 00c00000 3724 3725 If you set initrd_high to 0xFFFFFFFF, this is an 3726 indication to U-Boot that all addresses are legal 3727 for the Linux kernel, including addresses in flash 3728 memory. In this case U-Boot will NOT COPY the 3729 ramdisk at all. This may be useful to reduce the 3730 boot time on your system, but requires that this 3731 feature is supported by your Linux kernel. 3732 3733 ipaddr - IP address; needed for tftpboot command 3734 3735 loadaddr - Default load address for commands like "bootp", 3736 "rarpboot", "tftpboot", "loadb" or "diskboot" 3737 3738 loads_echo - see CONFIG_LOADS_ECHO 3739 3740 serverip - TFTP server IP address; needed for tftpboot command 3741 3742 bootretry - see CONFIG_BOOT_RETRY_TIME 3743 3744 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3745 3746 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3747 3748 ethprime - controls which interface is used first. 3749 3750 ethact - controls which interface is currently active. 3751 For example you can do the following 3752 3753 => setenv ethact FEC 3754 => ping 192.168.0.1 # traffic sent on FEC 3755 => setenv ethact SCC 3756 => ping 10.0.0.1 # traffic sent on SCC 3757 3758 ethrotate - When set to "no" U-Boot does not go through all 3759 available network interfaces. 3760 It just stays at the currently selected interface. 3761 3762 netretry - When set to "no" each network operation will 3763 either succeed or fail without retrying. 3764 When set to "once" the network operation will 3765 fail when all the available network interfaces 3766 are tried once without success. 3767 Useful on scripts which control the retry operation 3768 themselves. 3769 3770 npe_ucode - set load address for the NPE microcode 3771 3772 silent_linux - If set then Linux will be told to boot silently, by 3773 changing the console to be empty. If "yes" it will be 3774 made silent. If "no" it will not be made silent. If 3775 unset, then it will be made silent if the U-Boot console 3776 is silent. 3777 3778 tftpsrcp - If this is set, the value is used for TFTP's 3779 UDP source port. 3780 3781 tftpdstp - If this is set, the value is used for TFTP's UDP 3782 destination port instead of the Well Know Port 69. 3783 3784 tftpblocksize - Block size to use for TFTP transfers; if not set, 3785 we use the TFTP server's default block size 3786 3787 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3788 seconds, minimum value is 1000 = 1 second). Defines 3789 when a packet is considered to be lost so it has to 3790 be retransmitted. The default is 5000 = 5 seconds. 3791 Lowering this value may make downloads succeed 3792 faster in networks with high packet loss rates or 3793 with unreliable TFTP servers. 3794 3795 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3796 unit, minimum value = 0). Defines how many timeouts 3797 can happen during a single file transfer before that 3798 transfer is aborted. The default is 10, and 0 means 3799 'no timeouts allowed'. Increasing this value may help 3800 downloads succeed with high packet loss rates, or with 3801 unreliable TFTP servers or client hardware. 3802 3803 vlan - When set to a value < 4095 the traffic over 3804 Ethernet is encapsulated/received over 802.1q 3805 VLAN tagged frames. 3806 3807 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3808 Unsigned value, in milliseconds. If not set, the period will 3809 be either the default (28000), or a value based on 3810 CONFIG_NET_RETRY_COUNT, if defined. This value has 3811 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3812 3813The following image location variables contain the location of images 3814used in booting. The "Image" column gives the role of the image and is 3815not an environment variable name. The other columns are environment 3816variable names. "File Name" gives the name of the file on a TFTP 3817server, "RAM Address" gives the location in RAM the image will be 3818loaded to, and "Flash Location" gives the image's address in NOR 3819flash or offset in NAND flash. 3820 3821*Note* - these variables don't have to be defined for all boards, some 3822boards currently use other variables for these purposes, and some 3823boards use these variables for other purposes. 3824 3825Image File Name RAM Address Flash Location 3826----- --------- ----------- -------------- 3827u-boot u-boot u-boot_addr_r u-boot_addr 3828Linux kernel bootfile kernel_addr_r kernel_addr 3829device tree blob fdtfile fdt_addr_r fdt_addr 3830ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3831 3832The following environment variables may be used and automatically 3833updated by the network boot commands ("bootp" and "rarpboot"), 3834depending the information provided by your boot server: 3835 3836 bootfile - see above 3837 dnsip - IP address of your Domain Name Server 3838 dnsip2 - IP address of your secondary Domain Name Server 3839 gatewayip - IP address of the Gateway (Router) to use 3840 hostname - Target hostname 3841 ipaddr - see above 3842 netmask - Subnet Mask 3843 rootpath - Pathname of the root filesystem on the NFS server 3844 serverip - see above 3845 3846 3847There are two special Environment Variables: 3848 3849 serial# - contains hardware identification information such 3850 as type string and/or serial number 3851 ethaddr - Ethernet address 3852 3853These variables can be set only once (usually during manufacturing of 3854the board). U-Boot refuses to delete or overwrite these variables 3855once they have been set once. 3856 3857 3858Further special Environment Variables: 3859 3860 ver - Contains the U-Boot version string as printed 3861 with the "version" command. This variable is 3862 readonly (see CONFIG_VERSION_VARIABLE). 3863 3864 3865Please note that changes to some configuration parameters may take 3866only effect after the next boot (yes, that's just like Windoze :-). 3867 3868 3869Callback functions for environment variables: 3870--------------------------------------------- 3871 3872For some environment variables, the behavior of u-boot needs to change 3873when their values are changed. This functionality allows functions to 3874be associated with arbitrary variables. On creation, overwrite, or 3875deletion, the callback will provide the opportunity for some side 3876effect to happen or for the change to be rejected. 3877 3878The callbacks are named and associated with a function using the 3879U_BOOT_ENV_CALLBACK macro in your board or driver code. 3880 3881These callbacks are associated with variables in one of two ways. The 3882static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3883in the board configuration to a string that defines a list of 3884associations. The list must be in the following format: 3885 3886 entry = variable_name[:callback_name] 3887 list = entry[,list] 3888 3889If the callback name is not specified, then the callback is deleted. 3890Spaces are also allowed anywhere in the list. 3891 3892Callbacks can also be associated by defining the ".callbacks" variable 3893with the same list format above. Any association in ".callbacks" will 3894override any association in the static list. You can define 3895CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3896".callbacks" environment variable in the default or embedded environment. 3897 3898If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3899regular expression. This allows multiple variables to be connected to 3900the same callback without explicitly listing them all out. 3901 3902The signature of the callback functions is: 3903 3904 int callback(const char *name, const char *value, enum env_op op, int flags) 3905 3906* name - changed environment variable 3907* value - new value of the environment variable 3908* op - operation (create, overwrite, or delete) 3909* flags - attributes of the environment variable change, see flags H_* in 3910 include/search.h 3911 3912The return value is 0 if the variable change is accepted and 1 otherwise. 3913 3914Command Line Parsing: 3915===================== 3916 3917There are two different command line parsers available with U-Boot: 3918the old "simple" one, and the much more powerful "hush" shell: 3919 3920Old, simple command line parser: 3921-------------------------------- 3922 3923- supports environment variables (through setenv / saveenv commands) 3924- several commands on one line, separated by ';' 3925- variable substitution using "... ${name} ..." syntax 3926- special characters ('$', ';') can be escaped by prefixing with '\', 3927 for example: 3928 setenv bootcmd bootm \${address} 3929- You can also escape text by enclosing in single apostrophes, for example: 3930 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 3931 3932Hush shell: 3933----------- 3934 3935- similar to Bourne shell, with control structures like 3936 if...then...else...fi, for...do...done; while...do...done, 3937 until...do...done, ... 3938- supports environment ("global") variables (through setenv / saveenv 3939 commands) and local shell variables (through standard shell syntax 3940 "name=value"); only environment variables can be used with "run" 3941 command 3942 3943General rules: 3944-------------- 3945 3946(1) If a command line (or an environment variable executed by a "run" 3947 command) contains several commands separated by semicolon, and 3948 one of these commands fails, then the remaining commands will be 3949 executed anyway. 3950 3951(2) If you execute several variables with one call to run (i. e. 3952 calling run with a list of variables as arguments), any failing 3953 command will cause "run" to terminate, i. e. the remaining 3954 variables are not executed. 3955 3956Note for Redundant Ethernet Interfaces: 3957======================================= 3958 3959Some boards come with redundant Ethernet interfaces; U-Boot supports 3960such configurations and is capable of automatic selection of a 3961"working" interface when needed. MAC assignment works as follows: 3962 3963Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 3964MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 3965"eth1addr" (=>eth1), "eth2addr", ... 3966 3967If the network interface stores some valid MAC address (for instance 3968in SROM), this is used as default address if there is NO correspon- 3969ding setting in the environment; if the corresponding environment 3970variable is set, this overrides the settings in the card; that means: 3971 3972o If the SROM has a valid MAC address, and there is no address in the 3973 environment, the SROM's address is used. 3974 3975o If there is no valid address in the SROM, and a definition in the 3976 environment exists, then the value from the environment variable is 3977 used. 3978 3979o If both the SROM and the environment contain a MAC address, and 3980 both addresses are the same, this MAC address is used. 3981 3982o If both the SROM and the environment contain a MAC address, and the 3983 addresses differ, the value from the environment is used and a 3984 warning is printed. 3985 3986o If neither SROM nor the environment contain a MAC address, an error 3987 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 3988 a random, locally-assigned MAC is used. 3989 3990If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 3991will be programmed into hardware as part of the initialization process. This 3992may be skipped by setting the appropriate 'ethmacskip' environment variable. 3993The naming convention is as follows: 3994"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 3995 3996Image Formats: 3997============== 3998 3999U-Boot is capable of booting (and performing other auxiliary operations on) 4000images in two formats: 4001 4002New uImage format (FIT) 4003----------------------- 4004 4005Flexible and powerful format based on Flattened Image Tree -- FIT (similar 4006to Flattened Device Tree). It allows the use of images with multiple 4007components (several kernels, ramdisks, etc.), with contents protected by 4008SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 4009 4010 4011Old uImage format 4012----------------- 4013 4014Old image format is based on binary files which can be basically anything, 4015preceded by a special header; see the definitions in include/image.h for 4016details; basically, the header defines the following image properties: 4017 4018* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 4019 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 4020 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 4021 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 4022 INTEGRITY). 4023* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 4024 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 4025 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 4026* Compression Type (uncompressed, gzip, bzip2) 4027* Load Address 4028* Entry Point 4029* Image Name 4030* Image Timestamp 4031 4032The header is marked by a special Magic Number, and both the header 4033and the data portions of the image are secured against corruption by 4034CRC32 checksums. 4035 4036 4037Linux Support: 4038============== 4039 4040Although U-Boot should support any OS or standalone application 4041easily, the main focus has always been on Linux during the design of 4042U-Boot. 4043 4044U-Boot includes many features that so far have been part of some 4045special "boot loader" code within the Linux kernel. Also, any 4046"initrd" images to be used are no longer part of one big Linux image; 4047instead, kernel and "initrd" are separate images. This implementation 4048serves several purposes: 4049 4050- the same features can be used for other OS or standalone 4051 applications (for instance: using compressed images to reduce the 4052 Flash memory footprint) 4053 4054- it becomes much easier to port new Linux kernel versions because 4055 lots of low-level, hardware dependent stuff are done by U-Boot 4056 4057- the same Linux kernel image can now be used with different "initrd" 4058 images; of course this also means that different kernel images can 4059 be run with the same "initrd". This makes testing easier (you don't 4060 have to build a new "zImage.initrd" Linux image when you just 4061 change a file in your "initrd"). Also, a field-upgrade of the 4062 software is easier now. 4063 4064 4065Linux HOWTO: 4066============ 4067 4068Porting Linux to U-Boot based systems: 4069--------------------------------------- 4070 4071U-Boot cannot save you from doing all the necessary modifications to 4072configure the Linux device drivers for use with your target hardware 4073(no, we don't intend to provide a full virtual machine interface to 4074Linux :-). 4075 4076But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 4077 4078Just make sure your machine specific header file (for instance 4079include/asm-ppc/tqm8xx.h) includes the same definition of the Board 4080Information structure as we define in include/asm-<arch>/u-boot.h, 4081and make sure that your definition of IMAP_ADDR uses the same value 4082as your U-Boot configuration in CONFIG_SYS_IMMR. 4083 4084Note that U-Boot now has a driver model, a unified model for drivers. 4085If you are adding a new driver, plumb it into driver model. If there 4086is no uclass available, you are encouraged to create one. See 4087doc/driver-model. 4088 4089 4090Configuring the Linux kernel: 4091----------------------------- 4092 4093No specific requirements for U-Boot. Make sure you have some root 4094device (initial ramdisk, NFS) for your target system. 4095 4096 4097Building a Linux Image: 4098----------------------- 4099 4100With U-Boot, "normal" build targets like "zImage" or "bzImage" are 4101not used. If you use recent kernel source, a new build target 4102"uImage" will exist which automatically builds an image usable by 4103U-Boot. Most older kernels also have support for a "pImage" target, 4104which was introduced for our predecessor project PPCBoot and uses a 4105100% compatible format. 4106 4107Example: 4108 4109 make TQM850L_defconfig 4110 make oldconfig 4111 make dep 4112 make uImage 4113 4114The "uImage" build target uses a special tool (in 'tools/mkimage') to 4115encapsulate a compressed Linux kernel image with header information, 4116CRC32 checksum etc. for use with U-Boot. This is what we are doing: 4117 4118* build a standard "vmlinux" kernel image (in ELF binary format): 4119 4120* convert the kernel into a raw binary image: 4121 4122 ${CROSS_COMPILE}-objcopy -O binary \ 4123 -R .note -R .comment \ 4124 -S vmlinux linux.bin 4125 4126* compress the binary image: 4127 4128 gzip -9 linux.bin 4129 4130* package compressed binary image for U-Boot: 4131 4132 mkimage -A ppc -O linux -T kernel -C gzip \ 4133 -a 0 -e 0 -n "Linux Kernel Image" \ 4134 -d linux.bin.gz uImage 4135 4136 4137The "mkimage" tool can also be used to create ramdisk images for use 4138with U-Boot, either separated from the Linux kernel image, or 4139combined into one file. "mkimage" encapsulates the images with a 64 4140byte header containing information about target architecture, 4141operating system, image type, compression method, entry points, time 4142stamp, CRC32 checksums, etc. 4143 4144"mkimage" can be called in two ways: to verify existing images and 4145print the header information, or to build new images. 4146 4147In the first form (with "-l" option) mkimage lists the information 4148contained in the header of an existing U-Boot image; this includes 4149checksum verification: 4150 4151 tools/mkimage -l image 4152 -l ==> list image header information 4153 4154The second form (with "-d" option) is used to build a U-Boot image 4155from a "data file" which is used as image payload: 4156 4157 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 4158 -n name -d data_file image 4159 -A ==> set architecture to 'arch' 4160 -O ==> set operating system to 'os' 4161 -T ==> set image type to 'type' 4162 -C ==> set compression type 'comp' 4163 -a ==> set load address to 'addr' (hex) 4164 -e ==> set entry point to 'ep' (hex) 4165 -n ==> set image name to 'name' 4166 -d ==> use image data from 'datafile' 4167 4168Right now, all Linux kernels for PowerPC systems use the same load 4169address (0x00000000), but the entry point address depends on the 4170kernel version: 4171 4172- 2.2.x kernels have the entry point at 0x0000000C, 4173- 2.3.x and later kernels have the entry point at 0x00000000. 4174 4175So a typical call to build a U-Boot image would read: 4176 4177 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4178 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 4179 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 4180 > examples/uImage.TQM850L 4181 Image Name: 2.4.4 kernel for TQM850L 4182 Created: Wed Jul 19 02:34:59 2000 4183 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4184 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4185 Load Address: 0x00000000 4186 Entry Point: 0x00000000 4187 4188To verify the contents of the image (or check for corruption): 4189 4190 -> tools/mkimage -l examples/uImage.TQM850L 4191 Image Name: 2.4.4 kernel for TQM850L 4192 Created: Wed Jul 19 02:34:59 2000 4193 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4194 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4195 Load Address: 0x00000000 4196 Entry Point: 0x00000000 4197 4198NOTE: for embedded systems where boot time is critical you can trade 4199speed for memory and install an UNCOMPRESSED image instead: this 4200needs more space in Flash, but boots much faster since it does not 4201need to be uncompressed: 4202 4203 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 4204 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4205 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 4206 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 4207 > examples/uImage.TQM850L-uncompressed 4208 Image Name: 2.4.4 kernel for TQM850L 4209 Created: Wed Jul 19 02:34:59 2000 4210 Image Type: PowerPC Linux Kernel Image (uncompressed) 4211 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 4212 Load Address: 0x00000000 4213 Entry Point: 0x00000000 4214 4215 4216Similar you can build U-Boot images from a 'ramdisk.image.gz' file 4217when your kernel is intended to use an initial ramdisk: 4218 4219 -> tools/mkimage -n 'Simple Ramdisk Image' \ 4220 > -A ppc -O linux -T ramdisk -C gzip \ 4221 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 4222 Image Name: Simple Ramdisk Image 4223 Created: Wed Jan 12 14:01:50 2000 4224 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4225 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 4226 Load Address: 0x00000000 4227 Entry Point: 0x00000000 4228 4229The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i" 4230option performs the converse operation of the mkimage's second form (the "-d" 4231option). Given an image built by mkimage, the dumpimage extracts a "data file" 4232from the image: 4233 4234 tools/dumpimage -i image -T type -p position data_file 4235 -i ==> extract from the 'image' a specific 'data_file' 4236 -T ==> set image type to 'type' 4237 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image' 4238 4239 4240Installing a Linux Image: 4241------------------------- 4242 4243To downloading a U-Boot image over the serial (console) interface, 4244you must convert the image to S-Record format: 4245 4246 objcopy -I binary -O srec examples/image examples/image.srec 4247 4248The 'objcopy' does not understand the information in the U-Boot 4249image header, so the resulting S-Record file will be relative to 4250address 0x00000000. To load it to a given address, you need to 4251specify the target address as 'offset' parameter with the 'loads' 4252command. 4253 4254Example: install the image to address 0x40100000 (which on the 4255TQM8xxL is in the first Flash bank): 4256 4257 => erase 40100000 401FFFFF 4258 4259 .......... done 4260 Erased 8 sectors 4261 4262 => loads 40100000 4263 ## Ready for S-Record download ... 4264 ~>examples/image.srec 4265 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 4266 ... 4267 15989 15990 15991 15992 4268 [file transfer complete] 4269 [connected] 4270 ## Start Addr = 0x00000000 4271 4272 4273You can check the success of the download using the 'iminfo' command; 4274this includes a checksum verification so you can be sure no data 4275corruption happened: 4276 4277 => imi 40100000 4278 4279 ## Checking Image at 40100000 ... 4280 Image Name: 2.2.13 for initrd on TQM850L 4281 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4282 Data Size: 335725 Bytes = 327 kB = 0 MB 4283 Load Address: 00000000 4284 Entry Point: 0000000c 4285 Verifying Checksum ... OK 4286 4287 4288Boot Linux: 4289----------- 4290 4291The "bootm" command is used to boot an application that is stored in 4292memory (RAM or Flash). In case of a Linux kernel image, the contents 4293of the "bootargs" environment variable is passed to the kernel as 4294parameters. You can check and modify this variable using the 4295"printenv" and "setenv" commands: 4296 4297 4298 => printenv bootargs 4299 bootargs=root=/dev/ram 4300 4301 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4302 4303 => printenv bootargs 4304 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4305 4306 => bootm 40020000 4307 ## Booting Linux kernel at 40020000 ... 4308 Image Name: 2.2.13 for NFS on TQM850L 4309 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4310 Data Size: 381681 Bytes = 372 kB = 0 MB 4311 Load Address: 00000000 4312 Entry Point: 0000000c 4313 Verifying Checksum ... OK 4314 Uncompressing Kernel Image ... OK 4315 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 4316 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4317 time_init: decrementer frequency = 187500000/60 4318 Calibrating delay loop... 49.77 BogoMIPS 4319 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 4320 ... 4321 4322If you want to boot a Linux kernel with initial RAM disk, you pass 4323the memory addresses of both the kernel and the initrd image (PPBCOOT 4324format!) to the "bootm" command: 4325 4326 => imi 40100000 40200000 4327 4328 ## Checking Image at 40100000 ... 4329 Image Name: 2.2.13 for initrd on TQM850L 4330 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4331 Data Size: 335725 Bytes = 327 kB = 0 MB 4332 Load Address: 00000000 4333 Entry Point: 0000000c 4334 Verifying Checksum ... OK 4335 4336 ## Checking Image at 40200000 ... 4337 Image Name: Simple Ramdisk Image 4338 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4339 Data Size: 566530 Bytes = 553 kB = 0 MB 4340 Load Address: 00000000 4341 Entry Point: 00000000 4342 Verifying Checksum ... OK 4343 4344 => bootm 40100000 40200000 4345 ## Booting Linux kernel at 40100000 ... 4346 Image Name: 2.2.13 for initrd on TQM850L 4347 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4348 Data Size: 335725 Bytes = 327 kB = 0 MB 4349 Load Address: 00000000 4350 Entry Point: 0000000c 4351 Verifying Checksum ... OK 4352 Uncompressing Kernel Image ... OK 4353 ## Loading RAMDisk Image at 40200000 ... 4354 Image Name: Simple Ramdisk Image 4355 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4356 Data Size: 566530 Bytes = 553 kB = 0 MB 4357 Load Address: 00000000 4358 Entry Point: 00000000 4359 Verifying Checksum ... OK 4360 Loading Ramdisk ... OK 4361 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 4362 Boot arguments: root=/dev/ram 4363 time_init: decrementer frequency = 187500000/60 4364 Calibrating delay loop... 49.77 BogoMIPS 4365 ... 4366 RAMDISK: Compressed image found at block 0 4367 VFS: Mounted root (ext2 filesystem). 4368 4369 bash# 4370 4371Boot Linux and pass a flat device tree: 4372----------- 4373 4374First, U-Boot must be compiled with the appropriate defines. See the section 4375titled "Linux Kernel Interface" above for a more in depth explanation. The 4376following is an example of how to start a kernel and pass an updated 4377flat device tree: 4378 4379=> print oftaddr 4380oftaddr=0x300000 4381=> print oft 4382oft=oftrees/mpc8540ads.dtb 4383=> tftp $oftaddr $oft 4384Speed: 1000, full duplex 4385Using TSEC0 device 4386TFTP from server 192.168.1.1; our IP address is 192.168.1.101 4387Filename 'oftrees/mpc8540ads.dtb'. 4388Load address: 0x300000 4389Loading: # 4390done 4391Bytes transferred = 4106 (100a hex) 4392=> tftp $loadaddr $bootfile 4393Speed: 1000, full duplex 4394Using TSEC0 device 4395TFTP from server 192.168.1.1; our IP address is 192.168.1.2 4396Filename 'uImage'. 4397Load address: 0x200000 4398Loading:############ 4399done 4400Bytes transferred = 1029407 (fb51f hex) 4401=> print loadaddr 4402loadaddr=200000 4403=> print oftaddr 4404oftaddr=0x300000 4405=> bootm $loadaddr - $oftaddr 4406## Booting image at 00200000 ... 4407 Image Name: Linux-2.6.17-dirty 4408 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4409 Data Size: 1029343 Bytes = 1005.2 kB 4410 Load Address: 00000000 4411 Entry Point: 00000000 4412 Verifying Checksum ... OK 4413 Uncompressing Kernel Image ... OK 4414Booting using flat device tree at 0x300000 4415Using MPC85xx ADS machine description 4416Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 4417[snip] 4418 4419 4420More About U-Boot Image Types: 4421------------------------------ 4422 4423U-Boot supports the following image types: 4424 4425 "Standalone Programs" are directly runnable in the environment 4426 provided by U-Boot; it is expected that (if they behave 4427 well) you can continue to work in U-Boot after return from 4428 the Standalone Program. 4429 "OS Kernel Images" are usually images of some Embedded OS which 4430 will take over control completely. Usually these programs 4431 will install their own set of exception handlers, device 4432 drivers, set up the MMU, etc. - this means, that you cannot 4433 expect to re-enter U-Boot except by resetting the CPU. 4434 "RAMDisk Images" are more or less just data blocks, and their 4435 parameters (address, size) are passed to an OS kernel that is 4436 being started. 4437 "Multi-File Images" contain several images, typically an OS 4438 (Linux) kernel image and one or more data images like 4439 RAMDisks. This construct is useful for instance when you want 4440 to boot over the network using BOOTP etc., where the boot 4441 server provides just a single image file, but you want to get 4442 for instance an OS kernel and a RAMDisk image. 4443 4444 "Multi-File Images" start with a list of image sizes, each 4445 image size (in bytes) specified by an "uint32_t" in network 4446 byte order. This list is terminated by an "(uint32_t)0". 4447 Immediately after the terminating 0 follow the images, one by 4448 one, all aligned on "uint32_t" boundaries (size rounded up to 4449 a multiple of 4 bytes). 4450 4451 "Firmware Images" are binary images containing firmware (like 4452 U-Boot or FPGA images) which usually will be programmed to 4453 flash memory. 4454 4455 "Script files" are command sequences that will be executed by 4456 U-Boot's command interpreter; this feature is especially 4457 useful when you configure U-Boot to use a real shell (hush) 4458 as command interpreter. 4459 4460Booting the Linux zImage: 4461------------------------- 4462 4463On some platforms, it's possible to boot Linux zImage. This is done 4464using the "bootz" command. The syntax of "bootz" command is the same 4465as the syntax of "bootm" command. 4466 4467Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4468kernel with raw initrd images. The syntax is slightly different, the 4469address of the initrd must be augmented by it's size, in the following 4470format: "<initrd addres>:<initrd size>". 4471 4472 4473Standalone HOWTO: 4474================= 4475 4476One of the features of U-Boot is that you can dynamically load and 4477run "standalone" applications, which can use some resources of 4478U-Boot like console I/O functions or interrupt services. 4479 4480Two simple examples are included with the sources: 4481 4482"Hello World" Demo: 4483------------------- 4484 4485'examples/hello_world.c' contains a small "Hello World" Demo 4486application; it is automatically compiled when you build U-Boot. 4487It's configured to run at address 0x00040004, so you can play with it 4488like that: 4489 4490 => loads 4491 ## Ready for S-Record download ... 4492 ~>examples/hello_world.srec 4493 1 2 3 4 5 6 7 8 9 10 11 ... 4494 [file transfer complete] 4495 [connected] 4496 ## Start Addr = 0x00040004 4497 4498 => go 40004 Hello World! This is a test. 4499 ## Starting application at 0x00040004 ... 4500 Hello World 4501 argc = 7 4502 argv[0] = "40004" 4503 argv[1] = "Hello" 4504 argv[2] = "World!" 4505 argv[3] = "This" 4506 argv[4] = "is" 4507 argv[5] = "a" 4508 argv[6] = "test." 4509 argv[7] = "<NULL>" 4510 Hit any key to exit ... 4511 4512 ## Application terminated, rc = 0x0 4513 4514Another example, which demonstrates how to register a CPM interrupt 4515handler with the U-Boot code, can be found in 'examples/timer.c'. 4516Here, a CPM timer is set up to generate an interrupt every second. 4517The interrupt service routine is trivial, just printing a '.' 4518character, but this is just a demo program. The application can be 4519controlled by the following keys: 4520 4521 ? - print current values og the CPM Timer registers 4522 b - enable interrupts and start timer 4523 e - stop timer and disable interrupts 4524 q - quit application 4525 4526 => loads 4527 ## Ready for S-Record download ... 4528 ~>examples/timer.srec 4529 1 2 3 4 5 6 7 8 9 10 11 ... 4530 [file transfer complete] 4531 [connected] 4532 ## Start Addr = 0x00040004 4533 4534 => go 40004 4535 ## Starting application at 0x00040004 ... 4536 TIMERS=0xfff00980 4537 Using timer 1 4538 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4539 4540Hit 'b': 4541 [q, b, e, ?] Set interval 1000000 us 4542 Enabling timer 4543Hit '?': 4544 [q, b, e, ?] ........ 4545 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4546Hit '?': 4547 [q, b, e, ?] . 4548 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4549Hit '?': 4550 [q, b, e, ?] . 4551 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4552Hit '?': 4553 [q, b, e, ?] . 4554 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4555Hit 'e': 4556 [q, b, e, ?] ...Stopping timer 4557Hit 'q': 4558 [q, b, e, ?] ## Application terminated, rc = 0x0 4559 4560 4561Minicom warning: 4562================ 4563 4564Over time, many people have reported problems when trying to use the 4565"minicom" terminal emulation program for serial download. I (wd) 4566consider minicom to be broken, and recommend not to use it. Under 4567Unix, I recommend to use C-Kermit for general purpose use (and 4568especially for kermit binary protocol download ("loadb" command), and 4569use "cu" for S-Record download ("loads" command). See 4570http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4571for help with kermit. 4572 4573 4574Nevertheless, if you absolutely want to use it try adding this 4575configuration to your "File transfer protocols" section: 4576 4577 Name Program Name U/D FullScr IO-Red. Multi 4578 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4579 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4580 4581 4582NetBSD Notes: 4583============= 4584 4585Starting at version 0.9.2, U-Boot supports NetBSD both as host 4586(build U-Boot) and target system (boots NetBSD/mpc8xx). 4587 4588Building requires a cross environment; it is known to work on 4589NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4590need gmake since the Makefiles are not compatible with BSD make). 4591Note that the cross-powerpc package does not install include files; 4592attempting to build U-Boot will fail because <machine/ansi.h> is 4593missing. This file has to be installed and patched manually: 4594 4595 # cd /usr/pkg/cross/powerpc-netbsd/include 4596 # mkdir powerpc 4597 # ln -s powerpc machine 4598 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4599 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4600 4601Native builds *don't* work due to incompatibilities between native 4602and U-Boot include files. 4603 4604Booting assumes that (the first part of) the image booted is a 4605stage-2 loader which in turn loads and then invokes the kernel 4606proper. Loader sources will eventually appear in the NetBSD source 4607tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4608meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4609 4610 4611Implementation Internals: 4612========================= 4613 4614The following is not intended to be a complete description of every 4615implementation detail. However, it should help to understand the 4616inner workings of U-Boot and make it easier to port it to custom 4617hardware. 4618 4619 4620Initial Stack, Global Data: 4621--------------------------- 4622 4623The implementation of U-Boot is complicated by the fact that U-Boot 4624starts running out of ROM (flash memory), usually without access to 4625system RAM (because the memory controller is not initialized yet). 4626This means that we don't have writable Data or BSS segments, and BSS 4627is not initialized as zero. To be able to get a C environment working 4628at all, we have to allocate at least a minimal stack. Implementation 4629options for this are defined and restricted by the CPU used: Some CPU 4630models provide on-chip memory (like the IMMR area on MPC8xx and 4631MPC826x processors), on others (parts of) the data cache can be 4632locked as (mis-) used as memory, etc. 4633 4634 Chris Hallinan posted a good summary of these issues to the 4635 U-Boot mailing list: 4636 4637 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4638 From: "Chris Hallinan" <clh@net1plus.com> 4639 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4640 ... 4641 4642 Correct me if I'm wrong, folks, but the way I understand it 4643 is this: Using DCACHE as initial RAM for Stack, etc, does not 4644 require any physical RAM backing up the cache. The cleverness 4645 is that the cache is being used as a temporary supply of 4646 necessary storage before the SDRAM controller is setup. It's 4647 beyond the scope of this list to explain the details, but you 4648 can see how this works by studying the cache architecture and 4649 operation in the architecture and processor-specific manuals. 4650 4651 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4652 is another option for the system designer to use as an 4653 initial stack/RAM area prior to SDRAM being available. Either 4654 option should work for you. Using CS 4 should be fine if your 4655 board designers haven't used it for something that would 4656 cause you grief during the initial boot! It is frequently not 4657 used. 4658 4659 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4660 with your processor/board/system design. The default value 4661 you will find in any recent u-boot distribution in 4662 walnut.h should work for you. I'd set it to a value larger 4663 than your SDRAM module. If you have a 64MB SDRAM module, set 4664 it above 400_0000. Just make sure your board has no resources 4665 that are supposed to respond to that address! That code in 4666 start.S has been around a while and should work as is when 4667 you get the config right. 4668 4669 -Chris Hallinan 4670 DS4.COM, Inc. 4671 4672It is essential to remember this, since it has some impact on the C 4673code for the initialization procedures: 4674 4675* Initialized global data (data segment) is read-only. Do not attempt 4676 to write it. 4677 4678* Do not use any uninitialized global data (or implicitly initialized 4679 as zero data - BSS segment) at all - this is undefined, initiali- 4680 zation is performed later (when relocating to RAM). 4681 4682* Stack space is very limited. Avoid big data buffers or things like 4683 that. 4684 4685Having only the stack as writable memory limits means we cannot use 4686normal global data to share information between the code. But it 4687turned out that the implementation of U-Boot can be greatly 4688simplified by making a global data structure (gd_t) available to all 4689functions. We could pass a pointer to this data as argument to _all_ 4690functions, but this would bloat the code. Instead we use a feature of 4691the GCC compiler (Global Register Variables) to share the data: we 4692place a pointer (gd) to the global data into a register which we 4693reserve for this purpose. 4694 4695When choosing a register for such a purpose we are restricted by the 4696relevant (E)ABI specifications for the current architecture, and by 4697GCC's implementation. 4698 4699For PowerPC, the following registers have specific use: 4700 R1: stack pointer 4701 R2: reserved for system use 4702 R3-R4: parameter passing and return values 4703 R5-R10: parameter passing 4704 R13: small data area pointer 4705 R30: GOT pointer 4706 R31: frame pointer 4707 4708 (U-Boot also uses R12 as internal GOT pointer. r12 4709 is a volatile register so r12 needs to be reset when 4710 going back and forth between asm and C) 4711 4712 ==> U-Boot will use R2 to hold a pointer to the global data 4713 4714 Note: on PPC, we could use a static initializer (since the 4715 address of the global data structure is known at compile time), 4716 but it turned out that reserving a register results in somewhat 4717 smaller code - although the code savings are not that big (on 4718 average for all boards 752 bytes for the whole U-Boot image, 4719 624 text + 127 data). 4720 4721On ARM, the following registers are used: 4722 4723 R0: function argument word/integer result 4724 R1-R3: function argument word 4725 R9: platform specific 4726 R10: stack limit (used only if stack checking is enabled) 4727 R11: argument (frame) pointer 4728 R12: temporary workspace 4729 R13: stack pointer 4730 R14: link register 4731 R15: program counter 4732 4733 ==> U-Boot will use R9 to hold a pointer to the global data 4734 4735 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4736 4737On Nios II, the ABI is documented here: 4738 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4739 4740 ==> U-Boot will use gp to hold a pointer to the global data 4741 4742 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4743 to access small data sections, so gp is free. 4744 4745On NDS32, the following registers are used: 4746 4747 R0-R1: argument/return 4748 R2-R5: argument 4749 R15: temporary register for assembler 4750 R16: trampoline register 4751 R28: frame pointer (FP) 4752 R29: global pointer (GP) 4753 R30: link register (LP) 4754 R31: stack pointer (SP) 4755 PC: program counter (PC) 4756 4757 ==> U-Boot will use R10 to hold a pointer to the global data 4758 4759NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4760or current versions of GCC may "optimize" the code too much. 4761 4762On RISC-V, the following registers are used: 4763 4764 x0: hard-wired zero (zero) 4765 x1: return address (ra) 4766 x2: stack pointer (sp) 4767 x3: global pointer (gp) 4768 x4: thread pointer (tp) 4769 x5: link register (t0) 4770 x8: frame pointer (fp) 4771 x10-x11: arguments/return values (a0-1) 4772 x12-x17: arguments (a2-7) 4773 x28-31: temporaries (t3-6) 4774 pc: program counter (pc) 4775 4776 ==> U-Boot will use gp to hold a pointer to the global data 4777 4778Memory Management: 4779------------------ 4780 4781U-Boot runs in system state and uses physical addresses, i.e. the 4782MMU is not used either for address mapping nor for memory protection. 4783 4784The available memory is mapped to fixed addresses using the memory 4785controller. In this process, a contiguous block is formed for each 4786memory type (Flash, SDRAM, SRAM), even when it consists of several 4787physical memory banks. 4788 4789U-Boot is installed in the first 128 kB of the first Flash bank (on 4790TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4791booting and sizing and initializing DRAM, the code relocates itself 4792to the upper end of DRAM. Immediately below the U-Boot code some 4793memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4794configuration setting]. Below that, a structure with global Board 4795Info data is placed, followed by the stack (growing downward). 4796 4797Additionally, some exception handler code is copied to the low 8 kB 4798of DRAM (0x00000000 ... 0x00001FFF). 4799 4800So a typical memory configuration with 16 MB of DRAM could look like 4801this: 4802 4803 0x0000 0000 Exception Vector code 4804 : 4805 0x0000 1FFF 4806 0x0000 2000 Free for Application Use 4807 : 4808 : 4809 4810 : 4811 : 4812 0x00FB FF20 Monitor Stack (Growing downward) 4813 0x00FB FFAC Board Info Data and permanent copy of global data 4814 0x00FC 0000 Malloc Arena 4815 : 4816 0x00FD FFFF 4817 0x00FE 0000 RAM Copy of Monitor Code 4818 ... eventually: LCD or video framebuffer 4819 ... eventually: pRAM (Protected RAM - unchanged by reset) 4820 0x00FF FFFF [End of RAM] 4821 4822 4823System Initialization: 4824---------------------- 4825 4826In the reset configuration, U-Boot starts at the reset entry point 4827(on most PowerPC systems at address 0x00000100). Because of the reset 4828configuration for CS0# this is a mirror of the on board Flash memory. 4829To be able to re-map memory U-Boot then jumps to its link address. 4830To be able to implement the initialization code in C, a (small!) 4831initial stack is set up in the internal Dual Ported RAM (in case CPUs 4832which provide such a feature like), or in a locked part of the data 4833cache. After that, U-Boot initializes the CPU core, the caches and 4834the SIU. 4835 4836Next, all (potentially) available memory banks are mapped using a 4837preliminary mapping. For example, we put them on 512 MB boundaries 4838(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4839on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4840programmed for SDRAM access. Using the temporary configuration, a 4841simple memory test is run that determines the size of the SDRAM 4842banks. 4843 4844When there is more than one SDRAM bank, and the banks are of 4845different size, the largest is mapped first. For equal size, the first 4846bank (CS2#) is mapped first. The first mapping is always for address 48470x00000000, with any additional banks following immediately to create 4848contiguous memory starting from 0. 4849 4850Then, the monitor installs itself at the upper end of the SDRAM area 4851and allocates memory for use by malloc() and for the global Board 4852Info data; also, the exception vector code is copied to the low RAM 4853pages, and the final stack is set up. 4854 4855Only after this relocation will you have a "normal" C environment; 4856until that you are restricted in several ways, mostly because you are 4857running from ROM, and because the code will have to be relocated to a 4858new address in RAM. 4859 4860 4861U-Boot Porting Guide: 4862---------------------- 4863 4864[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4865list, October 2002] 4866 4867 4868int main(int argc, char *argv[]) 4869{ 4870 sighandler_t no_more_time; 4871 4872 signal(SIGALRM, no_more_time); 4873 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4874 4875 if (available_money > available_manpower) { 4876 Pay consultant to port U-Boot; 4877 return 0; 4878 } 4879 4880 Download latest U-Boot source; 4881 4882 Subscribe to u-boot mailing list; 4883 4884 if (clueless) 4885 email("Hi, I am new to U-Boot, how do I get started?"); 4886 4887 while (learning) { 4888 Read the README file in the top level directory; 4889 Read http://www.denx.de/twiki/bin/view/DULG/Manual; 4890 Read applicable doc/*.README; 4891 Read the source, Luke; 4892 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4893 } 4894 4895 if (available_money > toLocalCurrency ($2500)) 4896 Buy a BDI3000; 4897 else 4898 Add a lot of aggravation and time; 4899 4900 if (a similar board exists) { /* hopefully... */ 4901 cp -a board/<similar> board/<myboard> 4902 cp include/configs/<similar>.h include/configs/<myboard>.h 4903 } else { 4904 Create your own board support subdirectory; 4905 Create your own board include/configs/<myboard>.h file; 4906 } 4907 Edit new board/<myboard> files 4908 Edit new include/configs/<myboard>.h 4909 4910 while (!accepted) { 4911 while (!running) { 4912 do { 4913 Add / modify source code; 4914 } until (compiles); 4915 Debug; 4916 if (clueless) 4917 email("Hi, I am having problems..."); 4918 } 4919 Send patch file to the U-Boot email list; 4920 if (reasonable critiques) 4921 Incorporate improvements from email list code review; 4922 else 4923 Defend code as written; 4924 } 4925 4926 return 0; 4927} 4928 4929void no_more_time (int sig) 4930{ 4931 hire_a_guru(); 4932} 4933 4934 4935Coding Standards: 4936----------------- 4937 4938All contributions to U-Boot should conform to the Linux kernel 4939coding style; see the kernel coding style guide at 4940https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4941script "scripts/Lindent" in your Linux kernel source directory. 4942 4943Source files originating from a different project (for example the 4944MTD subsystem) are generally exempt from these guidelines and are not 4945reformatted to ease subsequent migration to newer versions of those 4946sources. 4947 4948Please note that U-Boot is implemented in C (and to some small parts in 4949Assembler); no C++ is used, so please do not use C++ style comments (//) 4950in your code. 4951 4952Please also stick to the following formatting rules: 4953- remove any trailing white space 4954- use TAB characters for indentation and vertical alignment, not spaces 4955- make sure NOT to use DOS '\r\n' line feeds 4956- do not add more than 2 consecutive empty lines to source files 4957- do not add trailing empty lines to source files 4958 4959Submissions which do not conform to the standards may be returned 4960with a request to reformat the changes. 4961 4962 4963Submitting Patches: 4964------------------- 4965 4966Since the number of patches for U-Boot is growing, we need to 4967establish some rules. Submissions which do not conform to these rules 4968may be rejected, even when they contain important and valuable stuff. 4969 4970Please see http://www.denx.de/wiki/U-Boot/Patches for details. 4971 4972Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 4973see https://lists.denx.de/listinfo/u-boot 4974 4975When you send a patch, please include the following information with 4976it: 4977 4978* For bug fixes: a description of the bug and how your patch fixes 4979 this bug. Please try to include a way of demonstrating that the 4980 patch actually fixes something. 4981 4982* For new features: a description of the feature and your 4983 implementation. 4984 4985* A CHANGELOG entry as plaintext (separate from the patch) 4986 4987* For major contributions, add a MAINTAINERS file with your 4988 information and associated file and directory references. 4989 4990* When you add support for a new board, don't forget to add a 4991 maintainer e-mail address to the boards.cfg file, too. 4992 4993* If your patch adds new configuration options, don't forget to 4994 document these in the README file. 4995 4996* The patch itself. If you are using git (which is *strongly* 4997 recommended) you can easily generate the patch using the 4998 "git format-patch". If you then use "git send-email" to send it to 4999 the U-Boot mailing list, you will avoid most of the common problems 5000 with some other mail clients. 5001 5002 If you cannot use git, use "diff -purN OLD NEW". If your version of 5003 diff does not support these options, then get the latest version of 5004 GNU diff. 5005 5006 The current directory when running this command shall be the parent 5007 directory of the U-Boot source tree (i. e. please make sure that 5008 your patch includes sufficient directory information for the 5009 affected files). 5010 5011 We prefer patches as plain text. MIME attachments are discouraged, 5012 and compressed attachments must not be used. 5013 5014* If one logical set of modifications affects or creates several 5015 files, all these changes shall be submitted in a SINGLE patch file. 5016 5017* Changesets that contain different, unrelated modifications shall be 5018 submitted as SEPARATE patches, one patch per changeset. 5019 5020 5021Notes: 5022 5023* Before sending the patch, run the buildman script on your patched 5024 source tree and make sure that no errors or warnings are reported 5025 for any of the boards. 5026 5027* Keep your modifications to the necessary minimum: A patch 5028 containing several unrelated changes or arbitrary reformats will be 5029 returned with a request to re-formatting / split it. 5030 5031* If you modify existing code, make sure that your new code does not 5032 add to the memory footprint of the code ;-) Small is beautiful! 5033 When adding new features, these should compile conditionally only 5034 (using #ifdef), and the resulting code with the new feature 5035 disabled must not need more memory than the old code without your 5036 modification. 5037 5038* Remember that there is a size limit of 100 kB per message on the 5039 u-boot mailing list. Bigger patches will be moderated. If they are 5040 reasonable and not too big, they will be acknowledged. But patches 5041 bigger than the size limit should be avoided. 5042