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- Multicast TFTP Mode: 1433 CONFIG_MCAST_TFTP 1434 1435 Defines whether you want to support multicast TFTP as per 1436 rfc-2090; for example to work with atftp. Lets lots of targets 1437 tftp down the same boot image concurrently. Note: the Ethernet 1438 driver in use must provide a function: mcast() to join/leave a 1439 multicast group. 1440 1441- BOOTP Recovery Mode: 1442 CONFIG_BOOTP_RANDOM_DELAY 1443 1444 If you have many targets in a network that try to 1445 boot using BOOTP, you may want to avoid that all 1446 systems send out BOOTP requests at precisely the same 1447 moment (which would happen for instance at recovery 1448 from a power failure, when all systems will try to 1449 boot, thus flooding the BOOTP server. Defining 1450 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1451 inserted before sending out BOOTP requests. The 1452 following delays are inserted then: 1453 1454 1st BOOTP request: delay 0 ... 1 sec 1455 2nd BOOTP request: delay 0 ... 2 sec 1456 3rd BOOTP request: delay 0 ... 4 sec 1457 4th and following 1458 BOOTP requests: delay 0 ... 8 sec 1459 1460 CONFIG_BOOTP_ID_CACHE_SIZE 1461 1462 BOOTP packets are uniquely identified using a 32-bit ID. The 1463 server will copy the ID from client requests to responses and 1464 U-Boot will use this to determine if it is the destination of 1465 an incoming response. Some servers will check that addresses 1466 aren't in use before handing them out (usually using an ARP 1467 ping) and therefore take up to a few hundred milliseconds to 1468 respond. Network congestion may also influence the time it 1469 takes for a response to make it back to the client. If that 1470 time is too long, U-Boot will retransmit requests. In order 1471 to allow earlier responses to still be accepted after these 1472 retransmissions, U-Boot's BOOTP client keeps a small cache of 1473 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1474 cache. The default is to keep IDs for up to four outstanding 1475 requests. Increasing this will allow U-Boot to accept offers 1476 from a BOOTP client in networks with unusually high latency. 1477 1478- DHCP Advanced Options: 1479 You can fine tune the DHCP functionality by defining 1480 CONFIG_BOOTP_* symbols: 1481 1482 CONFIG_BOOTP_NISDOMAIN 1483 CONFIG_BOOTP_BOOTFILESIZE 1484 CONFIG_BOOTP_SEND_HOSTNAME 1485 CONFIG_BOOTP_NTPSERVER 1486 CONFIG_BOOTP_TIMEOFFSET 1487 CONFIG_BOOTP_VENDOREX 1488 CONFIG_BOOTP_MAY_FAIL 1489 1490 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1491 environment variable, not the BOOTP server. 1492 1493 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1494 after the configured retry count, the call will fail 1495 instead of starting over. This can be used to fail over 1496 to Link-local IP address configuration if the DHCP server 1497 is not available. 1498 1499 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1500 to do a dynamic update of a DNS server. To do this, they 1501 need the hostname of the DHCP requester. 1502 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1503 of the "hostname" environment variable is passed as 1504 option 12 to the DHCP server. 1505 1506 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1507 1508 A 32bit value in microseconds for a delay between 1509 receiving a "DHCP Offer" and sending the "DHCP Request". 1510 This fixes a problem with certain DHCP servers that don't 1511 respond 100% of the time to a "DHCP request". E.g. On an 1512 AT91RM9200 processor running at 180MHz, this delay needed 1513 to be *at least* 15,000 usec before a Windows Server 2003 1514 DHCP server would reply 100% of the time. I recommend at 1515 least 50,000 usec to be safe. The alternative is to hope 1516 that one of the retries will be successful but note that 1517 the DHCP timeout and retry process takes a longer than 1518 this delay. 1519 1520 - Link-local IP address negotiation: 1521 Negotiate with other link-local clients on the local network 1522 for an address that doesn't require explicit configuration. 1523 This is especially useful if a DHCP server cannot be guaranteed 1524 to exist in all environments that the device must operate. 1525 1526 See doc/README.link-local for more information. 1527 1528 - MAC address from environment variables 1529 1530 FDT_SEQ_MACADDR_FROM_ENV 1531 1532 Fix-up device tree with MAC addresses fetched sequentially from 1533 environment variables. This config work on assumption that 1534 non-usable ethernet node of device-tree are either not present 1535 or their status has been marked as "disabled". 1536 1537 - CDP Options: 1538 CONFIG_CDP_DEVICE_ID 1539 1540 The device id used in CDP trigger frames. 1541 1542 CONFIG_CDP_DEVICE_ID_PREFIX 1543 1544 A two character string which is prefixed to the MAC address 1545 of the device. 1546 1547 CONFIG_CDP_PORT_ID 1548 1549 A printf format string which contains the ascii name of 1550 the port. Normally is set to "eth%d" which sets 1551 eth0 for the first Ethernet, eth1 for the second etc. 1552 1553 CONFIG_CDP_CAPABILITIES 1554 1555 A 32bit integer which indicates the device capabilities; 1556 0x00000010 for a normal host which does not forwards. 1557 1558 CONFIG_CDP_VERSION 1559 1560 An ascii string containing the version of the software. 1561 1562 CONFIG_CDP_PLATFORM 1563 1564 An ascii string containing the name of the platform. 1565 1566 CONFIG_CDP_TRIGGER 1567 1568 A 32bit integer sent on the trigger. 1569 1570 CONFIG_CDP_POWER_CONSUMPTION 1571 1572 A 16bit integer containing the power consumption of the 1573 device in .1 of milliwatts. 1574 1575 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1576 1577 A byte containing the id of the VLAN. 1578 1579- Status LED: CONFIG_LED_STATUS 1580 1581 Several configurations allow to display the current 1582 status using a LED. For instance, the LED will blink 1583 fast while running U-Boot code, stop blinking as 1584 soon as a reply to a BOOTP request was received, and 1585 start blinking slow once the Linux kernel is running 1586 (supported by a status LED driver in the Linux 1587 kernel). Defining CONFIG_LED_STATUS enables this 1588 feature in U-Boot. 1589 1590 Additional options: 1591 1592 CONFIG_LED_STATUS_GPIO 1593 The status LED can be connected to a GPIO pin. 1594 In such cases, the gpio_led driver can be used as a 1595 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1596 to include the gpio_led driver in the U-Boot binary. 1597 1598 CONFIG_GPIO_LED_INVERTED_TABLE 1599 Some GPIO connected LEDs may have inverted polarity in which 1600 case the GPIO high value corresponds to LED off state and 1601 GPIO low value corresponds to LED on state. 1602 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1603 with a list of GPIO LEDs that have inverted polarity. 1604 1605- I2C Support: CONFIG_SYS_I2C 1606 1607 This enable the NEW i2c subsystem, and will allow you to use 1608 i2c commands at the u-boot command line (as long as you set 1609 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c 1610 based realtime clock chips or other i2c devices. See 1611 common/cmd_i2c.c for a description of the command line 1612 interface. 1613 1614 ported i2c driver to the new framework: 1615 - drivers/i2c/soft_i2c.c: 1616 - activate first bus with CONFIG_SYS_I2C_SOFT define 1617 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1618 for defining speed and slave address 1619 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1620 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1621 for defining speed and slave address 1622 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1623 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1624 for defining speed and slave address 1625 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1626 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1627 for defining speed and slave address 1628 1629 - drivers/i2c/fsl_i2c.c: 1630 - activate i2c driver with CONFIG_SYS_I2C_FSL 1631 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1632 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1633 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1634 bus. 1635 - If your board supports a second fsl i2c bus, define 1636 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1637 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1638 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1639 second bus. 1640 1641 - drivers/i2c/tegra_i2c.c: 1642 - activate this driver with CONFIG_SYS_I2C_TEGRA 1643 - This driver adds 4 i2c buses with a fix speed from 1644 100000 and the slave addr 0! 1645 1646 - drivers/i2c/ppc4xx_i2c.c 1647 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1648 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1649 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1650 1651 - drivers/i2c/i2c_mxc.c 1652 - activate this driver with CONFIG_SYS_I2C_MXC 1653 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1654 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1655 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1656 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1657 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1658 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1659 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1660 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1661 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1662 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1663 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1664 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1665 If those defines are not set, default value is 100000 1666 for speed, and 0 for slave. 1667 1668 - drivers/i2c/rcar_i2c.c: 1669 - activate this driver with CONFIG_SYS_I2C_RCAR 1670 - This driver adds 4 i2c buses 1671 1672 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 1673 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 1674 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 1675 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 1676 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 1677 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 1678 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 1679 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 1680 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses 1681 1682 - drivers/i2c/sh_i2c.c: 1683 - activate this driver with CONFIG_SYS_I2C_SH 1684 - This driver adds from 2 to 5 i2c buses 1685 1686 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1687 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1688 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1689 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1690 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1691 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1692 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1693 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1694 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1695 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1696 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1697 1698 - drivers/i2c/omap24xx_i2c.c 1699 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1700 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1701 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1702 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1703 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1704 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1705 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1706 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1707 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1708 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1709 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1710 1711 - drivers/i2c/zynq_i2c.c 1712 - activate this driver with CONFIG_SYS_I2C_ZYNQ 1713 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting 1714 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr 1715 1716 - drivers/i2c/s3c24x0_i2c.c: 1717 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1718 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1719 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1720 with a fix speed from 100000 and the slave addr 0! 1721 1722 - drivers/i2c/ihs_i2c.c 1723 - activate this driver with CONFIG_SYS_I2C_IHS 1724 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1725 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1726 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1727 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1728 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1729 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1730 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1731 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1732 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1733 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1734 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1735 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1736 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1737 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1738 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1739 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1740 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1741 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1742 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1743 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1744 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1745 1746 additional defines: 1747 1748 CONFIG_SYS_NUM_I2C_BUSES 1749 Hold the number of i2c buses you want to use. 1750 1751 CONFIG_SYS_I2C_DIRECT_BUS 1752 define this, if you don't use i2c muxes on your hardware. 1753 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1754 omit this define. 1755 1756 CONFIG_SYS_I2C_MAX_HOPS 1757 define how many muxes are maximal consecutively connected 1758 on one i2c bus. If you not use i2c muxes, omit this 1759 define. 1760 1761 CONFIG_SYS_I2C_BUSES 1762 hold a list of buses you want to use, only used if 1763 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1764 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1765 CONFIG_SYS_NUM_I2C_BUSES = 9: 1766 1767 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1768 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1769 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1770 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1771 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1772 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1773 {1, {I2C_NULL_HOP}}, \ 1774 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1775 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1776 } 1777 1778 which defines 1779 bus 0 on adapter 0 without a mux 1780 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1781 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1782 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1783 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1784 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1785 bus 6 on adapter 1 without a mux 1786 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1787 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1788 1789 If you do not have i2c muxes on your board, omit this define. 1790 1791- Legacy I2C Support: 1792 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1793 then the following macros need to be defined (examples are 1794 from include/configs/lwmon.h): 1795 1796 I2C_INIT 1797 1798 (Optional). Any commands necessary to enable the I2C 1799 controller or configure ports. 1800 1801 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1802 1803 I2C_ACTIVE 1804 1805 The code necessary to make the I2C data line active 1806 (driven). If the data line is open collector, this 1807 define can be null. 1808 1809 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1810 1811 I2C_TRISTATE 1812 1813 The code necessary to make the I2C data line tri-stated 1814 (inactive). If the data line is open collector, this 1815 define can be null. 1816 1817 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1818 1819 I2C_READ 1820 1821 Code that returns true if the I2C data line is high, 1822 false if it is low. 1823 1824 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1825 1826 I2C_SDA(bit) 1827 1828 If <bit> is true, sets the I2C data line high. If it 1829 is false, it clears it (low). 1830 1831 eg: #define I2C_SDA(bit) \ 1832 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1833 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1834 1835 I2C_SCL(bit) 1836 1837 If <bit> is true, sets the I2C clock line high. If it 1838 is false, it clears it (low). 1839 1840 eg: #define I2C_SCL(bit) \ 1841 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1842 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1843 1844 I2C_DELAY 1845 1846 This delay is invoked four times per clock cycle so this 1847 controls the rate of data transfer. The data rate thus 1848 is 1 / (I2C_DELAY * 4). Often defined to be something 1849 like: 1850 1851 #define I2C_DELAY udelay(2) 1852 1853 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1854 1855 If your arch supports the generic GPIO framework (asm/gpio.h), 1856 then you may alternatively define the two GPIOs that are to be 1857 used as SCL / SDA. Any of the previous I2C_xxx macros will 1858 have GPIO-based defaults assigned to them as appropriate. 1859 1860 You should define these to the GPIO value as given directly to 1861 the generic GPIO functions. 1862 1863 CONFIG_SYS_I2C_INIT_BOARD 1864 1865 When a board is reset during an i2c bus transfer 1866 chips might think that the current transfer is still 1867 in progress. On some boards it is possible to access 1868 the i2c SCLK line directly, either by using the 1869 processor pin as a GPIO or by having a second pin 1870 connected to the bus. If this option is defined a 1871 custom i2c_init_board() routine in boards/xxx/board.c 1872 is run early in the boot sequence. 1873 1874 CONFIG_I2C_MULTI_BUS 1875 1876 This option allows the use of multiple I2C buses, each of which 1877 must have a controller. At any point in time, only one bus is 1878 active. To switch to a different bus, use the 'i2c dev' command. 1879 Note that bus numbering is zero-based. 1880 1881 CONFIG_SYS_I2C_NOPROBES 1882 1883 This option specifies a list of I2C devices that will be skipped 1884 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1885 is set, specify a list of bus-device pairs. Otherwise, specify 1886 a 1D array of device addresses 1887 1888 e.g. 1889 #undef CONFIG_I2C_MULTI_BUS 1890 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1891 1892 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1893 1894 #define CONFIG_I2C_MULTI_BUS 1895 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1896 1897 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1898 1899 CONFIG_SYS_SPD_BUS_NUM 1900 1901 If defined, then this indicates the I2C bus number for DDR SPD. 1902 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1903 1904 CONFIG_SYS_RTC_BUS_NUM 1905 1906 If defined, then this indicates the I2C bus number for the RTC. 1907 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1908 1909 CONFIG_SOFT_I2C_READ_REPEATED_START 1910 1911 defining this will force the i2c_read() function in 1912 the soft_i2c driver to perform an I2C repeated start 1913 between writing the address pointer and reading the 1914 data. If this define is omitted the default behaviour 1915 of doing a stop-start sequence will be used. Most I2C 1916 devices can use either method, but some require one or 1917 the other. 1918 1919- SPI Support: CONFIG_SPI 1920 1921 Enables SPI driver (so far only tested with 1922 SPI EEPROM, also an instance works with Crystal A/D and 1923 D/As on the SACSng board) 1924 1925 CONFIG_SOFT_SPI 1926 1927 Enables a software (bit-bang) SPI driver rather than 1928 using hardware support. This is a general purpose 1929 driver that only requires three general I/O port pins 1930 (two outputs, one input) to function. If this is 1931 defined, the board configuration must define several 1932 SPI configuration items (port pins to use, etc). For 1933 an example, see include/configs/sacsng.h. 1934 1935 CONFIG_HARD_SPI 1936 1937 Enables a hardware SPI driver for general-purpose reads 1938 and writes. As with CONFIG_SOFT_SPI, the board configuration 1939 must define a list of chip-select function pointers. 1940 Currently supported on some MPC8xxx processors. For an 1941 example, see include/configs/mpc8349emds.h. 1942 1943 CONFIG_SYS_SPI_MXC_WAIT 1944 Timeout for waiting until spi transfer completed. 1945 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1946 1947- FPGA Support: CONFIG_FPGA 1948 1949 Enables FPGA subsystem. 1950 1951 CONFIG_FPGA_<vendor> 1952 1953 Enables support for specific chip vendors. 1954 (ALTERA, XILINX) 1955 1956 CONFIG_FPGA_<family> 1957 1958 Enables support for FPGA family. 1959 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1960 1961 CONFIG_FPGA_COUNT 1962 1963 Specify the number of FPGA devices to support. 1964 1965 CONFIG_SYS_FPGA_PROG_FEEDBACK 1966 1967 Enable printing of hash marks during FPGA configuration. 1968 1969 CONFIG_SYS_FPGA_CHECK_BUSY 1970 1971 Enable checks on FPGA configuration interface busy 1972 status by the configuration function. This option 1973 will require a board or device specific function to 1974 be written. 1975 1976 CONFIG_FPGA_DELAY 1977 1978 If defined, a function that provides delays in the FPGA 1979 configuration driver. 1980 1981 CONFIG_SYS_FPGA_CHECK_CTRLC 1982 Allow Control-C to interrupt FPGA configuration 1983 1984 CONFIG_SYS_FPGA_CHECK_ERROR 1985 1986 Check for configuration errors during FPGA bitfile 1987 loading. For example, abort during Virtex II 1988 configuration if the INIT_B line goes low (which 1989 indicated a CRC error). 1990 1991 CONFIG_SYS_FPGA_WAIT_INIT 1992 1993 Maximum time to wait for the INIT_B line to de-assert 1994 after PROB_B has been de-asserted during a Virtex II 1995 FPGA configuration sequence. The default time is 500 1996 ms. 1997 1998 CONFIG_SYS_FPGA_WAIT_BUSY 1999 2000 Maximum time to wait for BUSY to de-assert during 2001 Virtex II FPGA configuration. The default is 5 ms. 2002 2003 CONFIG_SYS_FPGA_WAIT_CONFIG 2004 2005 Time to wait after FPGA configuration. The default is 2006 200 ms. 2007 2008- Configuration Management: 2009 CONFIG_BUILD_TARGET 2010 2011 Some SoCs need special image types (e.g. U-Boot binary 2012 with a special header) as build targets. By defining 2013 CONFIG_BUILD_TARGET in the SoC / board header, this 2014 special image will be automatically built upon calling 2015 make / buildman. 2016 2017 CONFIG_IDENT_STRING 2018 2019 If defined, this string will be added to the U-Boot 2020 version information (U_BOOT_VERSION) 2021 2022- Vendor Parameter Protection: 2023 2024 U-Boot considers the values of the environment 2025 variables "serial#" (Board Serial Number) and 2026 "ethaddr" (Ethernet Address) to be parameters that 2027 are set once by the board vendor / manufacturer, and 2028 protects these variables from casual modification by 2029 the user. Once set, these variables are read-only, 2030 and write or delete attempts are rejected. You can 2031 change this behaviour: 2032 2033 If CONFIG_ENV_OVERWRITE is #defined in your config 2034 file, the write protection for vendor parameters is 2035 completely disabled. Anybody can change or delete 2036 these parameters. 2037 2038 Alternatively, if you define _both_ an ethaddr in the 2039 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 2040 Ethernet address is installed in the environment, 2041 which can be changed exactly ONCE by the user. [The 2042 serial# is unaffected by this, i. e. it remains 2043 read-only.] 2044 2045 The same can be accomplished in a more flexible way 2046 for any variable by configuring the type of access 2047 to allow for those variables in the ".flags" variable 2048 or define CONFIG_ENV_FLAGS_LIST_STATIC. 2049 2050- Protected RAM: 2051 CONFIG_PRAM 2052 2053 Define this variable to enable the reservation of 2054 "protected RAM", i. e. RAM which is not overwritten 2055 by U-Boot. Define CONFIG_PRAM to hold the number of 2056 kB you want to reserve for pRAM. You can overwrite 2057 this default value by defining an environment 2058 variable "pram" to the number of kB you want to 2059 reserve. Note that the board info structure will 2060 still show the full amount of RAM. If pRAM is 2061 reserved, a new environment variable "mem" will 2062 automatically be defined to hold the amount of 2063 remaining RAM in a form that can be passed as boot 2064 argument to Linux, for instance like that: 2065 2066 setenv bootargs ... mem=\${mem} 2067 saveenv 2068 2069 This way you can tell Linux not to use this memory, 2070 either, which results in a memory region that will 2071 not be affected by reboots. 2072 2073 *WARNING* If your board configuration uses automatic 2074 detection of the RAM size, you must make sure that 2075 this memory test is non-destructive. So far, the 2076 following board configurations are known to be 2077 "pRAM-clean": 2078 2079 IVMS8, IVML24, SPD8xx, 2080 HERMES, IP860, RPXlite, LWMON, 2081 FLAGADM 2082 2083- Access to physical memory region (> 4GB) 2084 Some basic support is provided for operations on memory not 2085 normally accessible to U-Boot - e.g. some architectures 2086 support access to more than 4GB of memory on 32-bit 2087 machines using physical address extension or similar. 2088 Define CONFIG_PHYSMEM to access this basic support, which 2089 currently only supports clearing the memory. 2090 2091- Error Recovery: 2092 CONFIG_NET_RETRY_COUNT 2093 2094 This variable defines the number of retries for 2095 network operations like ARP, RARP, TFTP, or BOOTP 2096 before giving up the operation. If not defined, a 2097 default value of 5 is used. 2098 2099 CONFIG_ARP_TIMEOUT 2100 2101 Timeout waiting for an ARP reply in milliseconds. 2102 2103 CONFIG_NFS_TIMEOUT 2104 2105 Timeout in milliseconds used in NFS protocol. 2106 If you encounter "ERROR: Cannot umount" in nfs command, 2107 try longer timeout such as 2108 #define CONFIG_NFS_TIMEOUT 10000UL 2109 2110- Command Interpreter: 2111 CONFIG_SYS_PROMPT_HUSH_PS2 2112 2113 This defines the secondary prompt string, which is 2114 printed when the command interpreter needs more input 2115 to complete a command. Usually "> ". 2116 2117 Note: 2118 2119 In the current implementation, the local variables 2120 space and global environment variables space are 2121 separated. Local variables are those you define by 2122 simply typing `name=value'. To access a local 2123 variable later on, you have write `$name' or 2124 `${name}'; to execute the contents of a variable 2125 directly type `$name' at the command prompt. 2126 2127 Global environment variables are those you use 2128 setenv/printenv to work with. To run a command stored 2129 in such a variable, you need to use the run command, 2130 and you must not use the '$' sign to access them. 2131 2132 To store commands and special characters in a 2133 variable, please use double quotation marks 2134 surrounding the whole text of the variable, instead 2135 of the backslashes before semicolons and special 2136 symbols. 2137 2138- Command Line Editing and History: 2139 CONFIG_CMDLINE_PS_SUPPORT 2140 2141 Enable support for changing the command prompt string 2142 at run-time. Only static string is supported so far. 2143 The string is obtained from environment variables PS1 2144 and PS2. 2145 2146- Default Environment: 2147 CONFIG_EXTRA_ENV_SETTINGS 2148 2149 Define this to contain any number of null terminated 2150 strings (variable = value pairs) that will be part of 2151 the default environment compiled into the boot image. 2152 2153 For example, place something like this in your 2154 board's config file: 2155 2156 #define CONFIG_EXTRA_ENV_SETTINGS \ 2157 "myvar1=value1\0" \ 2158 "myvar2=value2\0" 2159 2160 Warning: This method is based on knowledge about the 2161 internal format how the environment is stored by the 2162 U-Boot code. This is NOT an official, exported 2163 interface! Although it is unlikely that this format 2164 will change soon, there is no guarantee either. 2165 You better know what you are doing here. 2166 2167 Note: overly (ab)use of the default environment is 2168 discouraged. Make sure to check other ways to preset 2169 the environment like the "source" command or the 2170 boot command first. 2171 2172 CONFIG_DELAY_ENVIRONMENT 2173 2174 Normally the environment is loaded when the board is 2175 initialised so that it is available to U-Boot. This inhibits 2176 that so that the environment is not available until 2177 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 2178 this is instead controlled by the value of 2179 /config/load-environment. 2180 2181- Serial Flash support 2182 Usage requires an initial 'sf probe' to define the serial 2183 flash parameters, followed by read/write/erase/update 2184 commands. 2185 2186 The following defaults may be provided by the platform 2187 to handle the common case when only a single serial 2188 flash is present on the system. 2189 2190 CONFIG_SF_DEFAULT_BUS Bus identifier 2191 CONFIG_SF_DEFAULT_CS Chip-select 2192 CONFIG_SF_DEFAULT_MODE (see include/spi.h) 2193 CONFIG_SF_DEFAULT_SPEED in Hz 2194 2195 2196- TFTP Fixed UDP Port: 2197 CONFIG_TFTP_PORT 2198 2199 If this is defined, the environment variable tftpsrcp 2200 is used to supply the TFTP UDP source port value. 2201 If tftpsrcp isn't defined, the normal pseudo-random port 2202 number generator is used. 2203 2204 Also, the environment variable tftpdstp is used to supply 2205 the TFTP UDP destination port value. If tftpdstp isn't 2206 defined, the normal port 69 is used. 2207 2208 The purpose for tftpsrcp is to allow a TFTP server to 2209 blindly start the TFTP transfer using the pre-configured 2210 target IP address and UDP port. This has the effect of 2211 "punching through" the (Windows XP) firewall, allowing 2212 the remainder of the TFTP transfer to proceed normally. 2213 A better solution is to properly configure the firewall, 2214 but sometimes that is not allowed. 2215 2216- Show boot progress: 2217 CONFIG_SHOW_BOOT_PROGRESS 2218 2219 Defining this option allows to add some board- 2220 specific code (calling a user-provided function 2221 "show_boot_progress(int)") that enables you to show 2222 the system's boot progress on some display (for 2223 example, some LED's) on your board. At the moment, 2224 the following checkpoints are implemented: 2225 2226 2227Legacy uImage format: 2228 2229 Arg Where When 2230 1 common/cmd_bootm.c before attempting to boot an image 2231 -1 common/cmd_bootm.c Image header has bad magic number 2232 2 common/cmd_bootm.c Image header has correct magic number 2233 -2 common/cmd_bootm.c Image header has bad checksum 2234 3 common/cmd_bootm.c Image header has correct checksum 2235 -3 common/cmd_bootm.c Image data has bad checksum 2236 4 common/cmd_bootm.c Image data has correct checksum 2237 -4 common/cmd_bootm.c Image is for unsupported architecture 2238 5 common/cmd_bootm.c Architecture check OK 2239 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi) 2240 6 common/cmd_bootm.c Image Type check OK 2241 -6 common/cmd_bootm.c gunzip uncompression error 2242 -7 common/cmd_bootm.c Unimplemented compression type 2243 7 common/cmd_bootm.c Uncompression OK 2244 8 common/cmd_bootm.c No uncompress/copy overwrite error 2245 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 2246 2247 9 common/image.c Start initial ramdisk verification 2248 -10 common/image.c Ramdisk header has bad magic number 2249 -11 common/image.c Ramdisk header has bad checksum 2250 10 common/image.c Ramdisk header is OK 2251 -12 common/image.c Ramdisk data has bad checksum 2252 11 common/image.c Ramdisk data has correct checksum 2253 12 common/image.c Ramdisk verification complete, start loading 2254 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk) 2255 13 common/image.c Start multifile image verification 2256 14 common/image.c No initial ramdisk, no multifile, continue. 2257 2258 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS 2259 2260 -30 arch/powerpc/lib/board.c Fatal error, hang the system 2261 -31 post/post.c POST test failed, detected by post_output_backlog() 2262 -32 post/post.c POST test failed, detected by post_run_single() 2263 2264 34 common/cmd_doc.c before loading a Image from a DOC device 2265 -35 common/cmd_doc.c Bad usage of "doc" command 2266 35 common/cmd_doc.c correct usage of "doc" command 2267 -36 common/cmd_doc.c No boot device 2268 36 common/cmd_doc.c correct boot device 2269 -37 common/cmd_doc.c Unknown Chip ID on boot device 2270 37 common/cmd_doc.c correct chip ID found, device available 2271 -38 common/cmd_doc.c Read Error on boot device 2272 38 common/cmd_doc.c reading Image header from DOC device OK 2273 -39 common/cmd_doc.c Image header has bad magic number 2274 39 common/cmd_doc.c Image header has correct magic number 2275 -40 common/cmd_doc.c Error reading Image from DOC device 2276 40 common/cmd_doc.c Image header has correct magic number 2277 41 common/cmd_ide.c before loading a Image from a IDE device 2278 -42 common/cmd_ide.c Bad usage of "ide" command 2279 42 common/cmd_ide.c correct usage of "ide" command 2280 -43 common/cmd_ide.c No boot device 2281 43 common/cmd_ide.c boot device found 2282 -44 common/cmd_ide.c Device not available 2283 44 common/cmd_ide.c Device available 2284 -45 common/cmd_ide.c wrong partition selected 2285 45 common/cmd_ide.c partition selected 2286 -46 common/cmd_ide.c Unknown partition table 2287 46 common/cmd_ide.c valid partition table found 2288 -47 common/cmd_ide.c Invalid partition type 2289 47 common/cmd_ide.c correct partition type 2290 -48 common/cmd_ide.c Error reading Image Header on boot device 2291 48 common/cmd_ide.c reading Image Header from IDE device OK 2292 -49 common/cmd_ide.c Image header has bad magic number 2293 49 common/cmd_ide.c Image header has correct magic number 2294 -50 common/cmd_ide.c Image header has bad checksum 2295 50 common/cmd_ide.c Image header has correct checksum 2296 -51 common/cmd_ide.c Error reading Image from IDE device 2297 51 common/cmd_ide.c reading Image from IDE device OK 2298 52 common/cmd_nand.c before loading a Image from a NAND device 2299 -53 common/cmd_nand.c Bad usage of "nand" command 2300 53 common/cmd_nand.c correct usage of "nand" command 2301 -54 common/cmd_nand.c No boot device 2302 54 common/cmd_nand.c boot device found 2303 -55 common/cmd_nand.c Unknown Chip ID on boot device 2304 55 common/cmd_nand.c correct chip ID found, device available 2305 -56 common/cmd_nand.c Error reading Image Header on boot device 2306 56 common/cmd_nand.c reading Image Header from NAND device OK 2307 -57 common/cmd_nand.c Image header has bad magic number 2308 57 common/cmd_nand.c Image header has correct magic number 2309 -58 common/cmd_nand.c Error reading Image from NAND device 2310 58 common/cmd_nand.c reading Image from NAND device OK 2311 2312 -60 common/env_common.c Environment has a bad CRC, using default 2313 2314 64 net/eth.c starting with Ethernet configuration. 2315 -64 net/eth.c no Ethernet found. 2316 65 net/eth.c Ethernet found. 2317 2318 -80 common/cmd_net.c usage wrong 2319 80 common/cmd_net.c before calling net_loop() 2320 -81 common/cmd_net.c some error in net_loop() occurred 2321 81 common/cmd_net.c net_loop() back without error 2322 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 2323 82 common/cmd_net.c trying automatic boot 2324 83 common/cmd_net.c running "source" command 2325 -83 common/cmd_net.c some error in automatic boot or "source" command 2326 84 common/cmd_net.c end without errors 2327 2328FIT uImage format: 2329 2330 Arg Where When 2331 100 common/cmd_bootm.c Kernel FIT Image has correct format 2332 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format 2333 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration 2334 -101 common/cmd_bootm.c Can't get configuration for kernel subimage 2335 102 common/cmd_bootm.c Kernel unit name specified 2336 -103 common/cmd_bootm.c Can't get kernel subimage node offset 2337 103 common/cmd_bootm.c Found configuration node 2338 104 common/cmd_bootm.c Got kernel subimage node offset 2339 -104 common/cmd_bootm.c Kernel subimage hash verification failed 2340 105 common/cmd_bootm.c Kernel subimage hash verification OK 2341 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture 2342 106 common/cmd_bootm.c Architecture check OK 2343 -106 common/cmd_bootm.c Kernel subimage has wrong type 2344 107 common/cmd_bootm.c Kernel subimage type OK 2345 -107 common/cmd_bootm.c Can't get kernel subimage data/size 2346 108 common/cmd_bootm.c Got kernel subimage data/size 2347 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT) 2348 -109 common/cmd_bootm.c Can't get kernel subimage type 2349 -110 common/cmd_bootm.c Can't get kernel subimage comp 2350 -111 common/cmd_bootm.c Can't get kernel subimage os 2351 -112 common/cmd_bootm.c Can't get kernel subimage load address 2352 -113 common/cmd_bootm.c Image uncompress/copy overwrite error 2353 2354 120 common/image.c Start initial ramdisk verification 2355 -120 common/image.c Ramdisk FIT image has incorrect format 2356 121 common/image.c Ramdisk FIT image has correct format 2357 122 common/image.c No ramdisk subimage unit name, using configuration 2358 -122 common/image.c Can't get configuration for ramdisk subimage 2359 123 common/image.c Ramdisk unit name specified 2360 -124 common/image.c Can't get ramdisk subimage node offset 2361 125 common/image.c Got ramdisk subimage node offset 2362 -125 common/image.c Ramdisk subimage hash verification failed 2363 126 common/image.c Ramdisk subimage hash verification OK 2364 -126 common/image.c Ramdisk subimage for unsupported architecture 2365 127 common/image.c Architecture check OK 2366 -127 common/image.c Can't get ramdisk subimage data/size 2367 128 common/image.c Got ramdisk subimage data/size 2368 129 common/image.c Can't get ramdisk load address 2369 -129 common/image.c Got ramdisk load address 2370 2371 -130 common/cmd_doc.c Incorrect FIT image format 2372 131 common/cmd_doc.c FIT image format OK 2373 2374 -140 common/cmd_ide.c Incorrect FIT image format 2375 141 common/cmd_ide.c FIT image format OK 2376 2377 -150 common/cmd_nand.c Incorrect FIT image format 2378 151 common/cmd_nand.c FIT image format OK 2379 2380- Standalone program support: 2381 CONFIG_STANDALONE_LOAD_ADDR 2382 2383 This option defines a board specific value for the 2384 address where standalone program gets loaded, thus 2385 overwriting the architecture dependent default 2386 settings. 2387 2388- Frame Buffer Address: 2389 CONFIG_FB_ADDR 2390 2391 Define CONFIG_FB_ADDR if you want to use specific 2392 address for frame buffer. This is typically the case 2393 when using a graphics controller has separate video 2394 memory. U-Boot will then place the frame buffer at 2395 the given address instead of dynamically reserving it 2396 in system RAM by calling lcd_setmem(), which grabs 2397 the memory for the frame buffer depending on the 2398 configured panel size. 2399 2400 Please see board_init_f function. 2401 2402- Automatic software updates via TFTP server 2403 CONFIG_UPDATE_TFTP 2404 CONFIG_UPDATE_TFTP_CNT_MAX 2405 CONFIG_UPDATE_TFTP_MSEC_MAX 2406 2407 These options enable and control the auto-update feature; 2408 for a more detailed description refer to doc/README.update. 2409 2410- MTD Support (mtdparts command, UBI support) 2411 CONFIG_MTD_UBI_WL_THRESHOLD 2412 This parameter defines the maximum difference between the highest 2413 erase counter value and the lowest erase counter value of eraseblocks 2414 of UBI devices. When this threshold is exceeded, UBI starts performing 2415 wear leveling by means of moving data from eraseblock with low erase 2416 counter to eraseblocks with high erase counter. 2417 2418 The default value should be OK for SLC NAND flashes, NOR flashes and 2419 other flashes which have eraseblock life-cycle 100000 or more. 2420 However, in case of MLC NAND flashes which typically have eraseblock 2421 life-cycle less than 10000, the threshold should be lessened (e.g., 2422 to 128 or 256, although it does not have to be power of 2). 2423 2424 default: 4096 2425 2426 CONFIG_MTD_UBI_BEB_LIMIT 2427 This option specifies the maximum bad physical eraseblocks UBI 2428 expects on the MTD device (per 1024 eraseblocks). If the 2429 underlying flash does not admit of bad eraseblocks (e.g. NOR 2430 flash), this value is ignored. 2431 2432 NAND datasheets often specify the minimum and maximum NVM 2433 (Number of Valid Blocks) for the flashes' endurance lifetime. 2434 The maximum expected bad eraseblocks per 1024 eraseblocks 2435 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2436 which gives 20 for most NANDs (MaxNVB is basically the total 2437 count of eraseblocks on the chip). 2438 2439 To put it differently, if this value is 20, UBI will try to 2440 reserve about 1.9% of physical eraseblocks for bad blocks 2441 handling. And that will be 1.9% of eraseblocks on the entire 2442 NAND chip, not just the MTD partition UBI attaches. This means 2443 that if you have, say, a NAND flash chip admits maximum 40 bad 2444 eraseblocks, and it is split on two MTD partitions of the same 2445 size, UBI will reserve 40 eraseblocks when attaching a 2446 partition. 2447 2448 default: 20 2449 2450 CONFIG_MTD_UBI_FASTMAP 2451 Fastmap is a mechanism which allows attaching an UBI device 2452 in nearly constant time. Instead of scanning the whole MTD device it 2453 only has to locate a checkpoint (called fastmap) on the device. 2454 The on-flash fastmap contains all information needed to attach 2455 the device. Using fastmap makes only sense on large devices where 2456 attaching by scanning takes long. UBI will not automatically install 2457 a fastmap on old images, but you can set the UBI parameter 2458 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2459 that fastmap-enabled images are still usable with UBI implementations 2460 without fastmap support. On typical flash devices the whole fastmap 2461 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2462 2463 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2464 Set this parameter to enable fastmap automatically on images 2465 without a fastmap. 2466 default: 0 2467 2468 CONFIG_MTD_UBI_FM_DEBUG 2469 Enable UBI fastmap debug 2470 default: 0 2471 2472- SPL framework 2473 CONFIG_SPL 2474 Enable building of SPL globally. 2475 2476 CONFIG_SPL_LDSCRIPT 2477 LDSCRIPT for linking the SPL binary. 2478 2479 CONFIG_SPL_MAX_FOOTPRINT 2480 Maximum size in memory allocated to the SPL, BSS included. 2481 When defined, the linker checks that the actual memory 2482 used by SPL from _start to __bss_end does not exceed it. 2483 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2484 must not be both defined at the same time. 2485 2486 CONFIG_SPL_MAX_SIZE 2487 Maximum size of the SPL image (text, data, rodata, and 2488 linker lists sections), BSS excluded. 2489 When defined, the linker checks that the actual size does 2490 not exceed it. 2491 2492 CONFIG_SPL_TEXT_BASE 2493 TEXT_BASE for linking the SPL binary. 2494 2495 CONFIG_SPL_RELOC_TEXT_BASE 2496 Address to relocate to. If unspecified, this is equal to 2497 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2498 2499 CONFIG_SPL_BSS_START_ADDR 2500 Link address for the BSS within the SPL binary. 2501 2502 CONFIG_SPL_BSS_MAX_SIZE 2503 Maximum size in memory allocated to the SPL BSS. 2504 When defined, the linker checks that the actual memory used 2505 by SPL from __bss_start to __bss_end does not exceed it. 2506 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2507 must not be both defined at the same time. 2508 2509 CONFIG_SPL_STACK 2510 Adress of the start of the stack SPL will use 2511 2512 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2513 When defined, SPL will panic() if the image it has 2514 loaded does not have a signature. 2515 Defining this is useful when code which loads images 2516 in SPL cannot guarantee that absolutely all read errors 2517 will be caught. 2518 An example is the LPC32XX MLC NAND driver, which will 2519 consider that a completely unreadable NAND block is bad, 2520 and thus should be skipped silently. 2521 2522 CONFIG_SPL_RELOC_STACK 2523 Adress of the start of the stack SPL will use after 2524 relocation. If unspecified, this is equal to 2525 CONFIG_SPL_STACK. 2526 2527 CONFIG_SYS_SPL_MALLOC_START 2528 Starting address of the malloc pool used in SPL. 2529 When this option is set the full malloc is used in SPL and 2530 it is set up by spl_init() and before that, the simple malloc() 2531 can be used if CONFIG_SYS_MALLOC_F is defined. 2532 2533 CONFIG_SYS_SPL_MALLOC_SIZE 2534 The size of the malloc pool used in SPL. 2535 2536 CONFIG_SPL_OS_BOOT 2537 Enable booting directly to an OS from SPL. 2538 See also: doc/README.falcon 2539 2540 CONFIG_SPL_DISPLAY_PRINT 2541 For ARM, enable an optional function to print more information 2542 about the running system. 2543 2544 CONFIG_SPL_INIT_MINIMAL 2545 Arch init code should be built for a very small image 2546 2547 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2548 Partition on the MMC to load U-Boot from when the MMC is being 2549 used in raw mode 2550 2551 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2552 Sector to load kernel uImage from when MMC is being 2553 used in raw mode (for Falcon mode) 2554 2555 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2556 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2557 Sector and number of sectors to load kernel argument 2558 parameters from when MMC is being used in raw mode 2559 (for falcon mode) 2560 2561 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 2562 Partition on the MMC to load U-Boot from when the MMC is being 2563 used in fs mode 2564 2565 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2566 Filename to read to load U-Boot when reading from filesystem 2567 2568 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2569 Filename to read to load kernel uImage when reading 2570 from filesystem (for Falcon mode) 2571 2572 CONFIG_SPL_FS_LOAD_ARGS_NAME 2573 Filename to read to load kernel argument parameters 2574 when reading from filesystem (for Falcon mode) 2575 2576 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2577 Set this for NAND SPL on PPC mpc83xx targets, so that 2578 start.S waits for the rest of the SPL to load before 2579 continuing (the hardware starts execution after just 2580 loading the first page rather than the full 4K). 2581 2582 CONFIG_SPL_SKIP_RELOCATE 2583 Avoid SPL relocation 2584 2585 CONFIG_SPL_NAND_BASE 2586 Include nand_base.c in the SPL. Requires 2587 CONFIG_SPL_NAND_DRIVERS. 2588 2589 CONFIG_SPL_NAND_DRIVERS 2590 SPL uses normal NAND drivers, not minimal drivers. 2591 2592 CONFIG_SPL_NAND_IDENT 2593 SPL uses the chip ID list to identify the NAND flash. 2594 Requires CONFIG_SPL_NAND_BASE. 2595 2596 CONFIG_SPL_NAND_ECC 2597 Include standard software ECC in the SPL 2598 2599 CONFIG_SPL_NAND_SIMPLE 2600 Support for NAND boot using simple NAND drivers that 2601 expose the cmd_ctrl() interface. 2602 2603 CONFIG_SPL_UBI 2604 Support for a lightweight UBI (fastmap) scanner and 2605 loader 2606 2607 CONFIG_SPL_NAND_RAW_ONLY 2608 Support to boot only raw u-boot.bin images. Use this only 2609 if you need to save space. 2610 2611 CONFIG_SPL_COMMON_INIT_DDR 2612 Set for common ddr init with serial presence detect in 2613 SPL binary. 2614 2615 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2616 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2617 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2618 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2619 CONFIG_SYS_NAND_ECCBYTES 2620 Defines the size and behavior of the NAND that SPL uses 2621 to read U-Boot 2622 2623 CONFIG_SPL_NAND_BOOT 2624 Add support NAND boot 2625 2626 CONFIG_SYS_NAND_U_BOOT_OFFS 2627 Location in NAND to read U-Boot from 2628 2629 CONFIG_SYS_NAND_U_BOOT_DST 2630 Location in memory to load U-Boot to 2631 2632 CONFIG_SYS_NAND_U_BOOT_SIZE 2633 Size of image to load 2634 2635 CONFIG_SYS_NAND_U_BOOT_START 2636 Entry point in loaded image to jump to 2637 2638 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2639 Define this if you need to first read the OOB and then the 2640 data. This is used, for example, on davinci platforms. 2641 2642 CONFIG_SPL_RAM_DEVICE 2643 Support for running image already present in ram, in SPL binary 2644 2645 CONFIG_SPL_PAD_TO 2646 Image offset to which the SPL should be padded before appending 2647 the SPL payload. By default, this is defined as 2648 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2649 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2650 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2651 2652 CONFIG_SPL_TARGET 2653 Final target image containing SPL and payload. Some SPLs 2654 use an arch-specific makefile fragment instead, for 2655 example if more than one image needs to be produced. 2656 2657 CONFIG_SPL_FIT_PRINT 2658 Printing information about a FIT image adds quite a bit of 2659 code to SPL. So this is normally disabled in SPL. Use this 2660 option to re-enable it. This will affect the output of the 2661 bootm command when booting a FIT image. 2662 2663- TPL framework 2664 CONFIG_TPL 2665 Enable building of TPL globally. 2666 2667 CONFIG_TPL_PAD_TO 2668 Image offset to which the TPL should be padded before appending 2669 the TPL payload. By default, this is defined as 2670 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2671 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2672 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2673 2674- Interrupt support (PPC): 2675 2676 There are common interrupt_init() and timer_interrupt() 2677 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2678 for CPU specific initialization. interrupt_init_cpu() 2679 should set decrementer_count to appropriate value. If 2680 CPU resets decrementer automatically after interrupt 2681 (ppc4xx) it should set decrementer_count to zero. 2682 timer_interrupt() calls timer_interrupt_cpu() for CPU 2683 specific handling. If board has watchdog / status_led 2684 / other_activity_monitor it works automatically from 2685 general timer_interrupt(). 2686 2687 2688Board initialization settings: 2689------------------------------ 2690 2691During Initialization u-boot calls a number of board specific functions 2692to allow the preparation of board specific prerequisites, e.g. pin setup 2693before drivers are initialized. To enable these callbacks the 2694following configuration macros have to be defined. Currently this is 2695architecture specific, so please check arch/your_architecture/lib/board.c 2696typically in board_init_f() and board_init_r(). 2697 2698- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2699- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2700- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2701- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2702 2703Configuration Settings: 2704----------------------- 2705 2706- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2707 Optionally it can be defined to support 64-bit memory commands. 2708 2709- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2710 undefine this when you're short of memory. 2711 2712- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2713 width of the commands listed in the 'help' command output. 2714 2715- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2716 prompt for user input. 2717 2718- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2719 2720- CONFIG_SYS_PBSIZE: Buffer size for Console output 2721 2722- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2723 2724- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2725 the application (usually a Linux kernel) when it is 2726 booted 2727 2728- CONFIG_SYS_BAUDRATE_TABLE: 2729 List of legal baudrate settings for this board. 2730 2731- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: 2732 Begin and End addresses of the area used by the 2733 simple memory test. 2734 2735- CONFIG_SYS_MEMTEST_SCRATCH: 2736 Scratch address used by the alternate memory test 2737 You only need to set this if address zero isn't writeable 2738 2739- CONFIG_SYS_MEM_RESERVE_SECURE 2740 Only implemented for ARMv8 for now. 2741 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2742 is substracted from total RAM and won't be reported to OS. 2743 This memory can be used as secure memory. A variable 2744 gd->arch.secure_ram is used to track the location. In systems 2745 the RAM base is not zero, or RAM is divided into banks, 2746 this variable needs to be recalcuated to get the address. 2747 2748- CONFIG_SYS_MEM_TOP_HIDE: 2749 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2750 this specified memory area will get subtracted from the top 2751 (end) of RAM and won't get "touched" at all by U-Boot. By 2752 fixing up gd->ram_size the Linux kernel should gets passed 2753 the now "corrected" memory size and won't touch it either. 2754 This should work for arch/ppc and arch/powerpc. Only Linux 2755 board ports in arch/powerpc with bootwrapper support that 2756 recalculate the memory size from the SDRAM controller setup 2757 will have to get fixed in Linux additionally. 2758 2759 This option can be used as a workaround for the 440EPx/GRx 2760 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2761 be touched. 2762 2763 WARNING: Please make sure that this value is a multiple of 2764 the Linux page size (normally 4k). If this is not the case, 2765 then the end address of the Linux memory will be located at a 2766 non page size aligned address and this could cause major 2767 problems. 2768 2769- CONFIG_SYS_LOADS_BAUD_CHANGE: 2770 Enable temporary baudrate change while serial download 2771 2772- CONFIG_SYS_SDRAM_BASE: 2773 Physical start address of SDRAM. _Must_ be 0 here. 2774 2775- CONFIG_SYS_FLASH_BASE: 2776 Physical start address of Flash memory. 2777 2778- CONFIG_SYS_MONITOR_BASE: 2779 Physical start address of boot monitor code (set by 2780 make config files to be same as the text base address 2781 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2782 CONFIG_SYS_FLASH_BASE when booting from flash. 2783 2784- CONFIG_SYS_MONITOR_LEN: 2785 Size of memory reserved for monitor code, used to 2786 determine _at_compile_time_ (!) if the environment is 2787 embedded within the U-Boot image, or in a separate 2788 flash sector. 2789 2790- CONFIG_SYS_MALLOC_LEN: 2791 Size of DRAM reserved for malloc() use. 2792 2793- CONFIG_SYS_MALLOC_F_LEN 2794 Size of the malloc() pool for use before relocation. If 2795 this is defined, then a very simple malloc() implementation 2796 will become available before relocation. The address is just 2797 below the global data, and the stack is moved down to make 2798 space. 2799 2800 This feature allocates regions with increasing addresses 2801 within the region. calloc() is supported, but realloc() 2802 is not available. free() is supported but does nothing. 2803 The memory will be freed (or in fact just forgotten) when 2804 U-Boot relocates itself. 2805 2806- CONFIG_SYS_MALLOC_SIMPLE 2807 Provides a simple and small malloc() and calloc() for those 2808 boards which do not use the full malloc in SPL (which is 2809 enabled with CONFIG_SYS_SPL_MALLOC_START). 2810 2811- CONFIG_SYS_NONCACHED_MEMORY: 2812 Size of non-cached memory area. This area of memory will be 2813 typically located right below the malloc() area and mapped 2814 uncached in the MMU. This is useful for drivers that would 2815 otherwise require a lot of explicit cache maintenance. For 2816 some drivers it's also impossible to properly maintain the 2817 cache. For example if the regions that need to be flushed 2818 are not a multiple of the cache-line size, *and* padding 2819 cannot be allocated between the regions to align them (i.e. 2820 if the HW requires a contiguous array of regions, and the 2821 size of each region is not cache-aligned), then a flush of 2822 one region may result in overwriting data that hardware has 2823 written to another region in the same cache-line. This can 2824 happen for example in network drivers where descriptors for 2825 buffers are typically smaller than the CPU cache-line (e.g. 2826 16 bytes vs. 32 or 64 bytes). 2827 2828 Non-cached memory is only supported on 32-bit ARM at present. 2829 2830- CONFIG_SYS_BOOTM_LEN: 2831 Normally compressed uImages are limited to an 2832 uncompressed size of 8 MBytes. If this is not enough, 2833 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2834 to adjust this setting to your needs. 2835 2836- CONFIG_SYS_BOOTMAPSZ: 2837 Maximum size of memory mapped by the startup code of 2838 the Linux kernel; all data that must be processed by 2839 the Linux kernel (bd_info, boot arguments, FDT blob if 2840 used) must be put below this limit, unless "bootm_low" 2841 environment variable is defined and non-zero. In such case 2842 all data for the Linux kernel must be between "bootm_low" 2843 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2844 variable "bootm_mapsize" will override the value of 2845 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2846 then the value in "bootm_size" will be used instead. 2847 2848- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2849 Enable initrd_high functionality. If defined then the 2850 initrd_high feature is enabled and the bootm ramdisk subcommand 2851 is enabled. 2852 2853- CONFIG_SYS_BOOT_GET_CMDLINE: 2854 Enables allocating and saving kernel cmdline in space between 2855 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2856 2857- CONFIG_SYS_BOOT_GET_KBD: 2858 Enables allocating and saving a kernel copy of the bd_info in 2859 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2860 2861- CONFIG_SYS_MAX_FLASH_BANKS: 2862 Max number of Flash memory banks 2863 2864- CONFIG_SYS_MAX_FLASH_SECT: 2865 Max number of sectors on a Flash chip 2866 2867- CONFIG_SYS_FLASH_ERASE_TOUT: 2868 Timeout for Flash erase operations (in ms) 2869 2870- CONFIG_SYS_FLASH_WRITE_TOUT: 2871 Timeout for Flash write operations (in ms) 2872 2873- CONFIG_SYS_FLASH_LOCK_TOUT 2874 Timeout for Flash set sector lock bit operation (in ms) 2875 2876- CONFIG_SYS_FLASH_UNLOCK_TOUT 2877 Timeout for Flash clear lock bits operation (in ms) 2878 2879- CONFIG_SYS_FLASH_PROTECTION 2880 If defined, hardware flash sectors protection is used 2881 instead of U-Boot software protection. 2882 2883- CONFIG_SYS_DIRECT_FLASH_TFTP: 2884 2885 Enable TFTP transfers directly to flash memory; 2886 without this option such a download has to be 2887 performed in two steps: (1) download to RAM, and (2) 2888 copy from RAM to flash. 2889 2890 The two-step approach is usually more reliable, since 2891 you can check if the download worked before you erase 2892 the flash, but in some situations (when system RAM is 2893 too limited to allow for a temporary copy of the 2894 downloaded image) this option may be very useful. 2895 2896- CONFIG_SYS_FLASH_CFI: 2897 Define if the flash driver uses extra elements in the 2898 common flash structure for storing flash geometry. 2899 2900- CONFIG_FLASH_CFI_DRIVER 2901 This option also enables the building of the cfi_flash driver 2902 in the drivers directory 2903 2904- CONFIG_FLASH_CFI_MTD 2905 This option enables the building of the cfi_mtd driver 2906 in the drivers directory. The driver exports CFI flash 2907 to the MTD layer. 2908 2909- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2910 Use buffered writes to flash. 2911 2912- CONFIG_FLASH_SPANSION_S29WS_N 2913 s29ws-n MirrorBit flash has non-standard addresses for buffered 2914 write commands. 2915 2916- CONFIG_SYS_FLASH_QUIET_TEST 2917 If this option is defined, the common CFI flash doesn't 2918 print it's warning upon not recognized FLASH banks. This 2919 is useful, if some of the configured banks are only 2920 optionally available. 2921 2922- CONFIG_FLASH_SHOW_PROGRESS 2923 If defined (must be an integer), print out countdown 2924 digits and dots. Recommended value: 45 (9..1) for 80 2925 column displays, 15 (3..1) for 40 column displays. 2926 2927- CONFIG_FLASH_VERIFY 2928 If defined, the content of the flash (destination) is compared 2929 against the source after the write operation. An error message 2930 will be printed when the contents are not identical. 2931 Please note that this option is useless in nearly all cases, 2932 since such flash programming errors usually are detected earlier 2933 while unprotecting/erasing/programming. Please only enable 2934 this option if you really know what you are doing. 2935 2936- CONFIG_SYS_RX_ETH_BUFFER: 2937 Defines the number of Ethernet receive buffers. On some 2938 Ethernet controllers it is recommended to set this value 2939 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2940 buffers can be full shortly after enabling the interface 2941 on high Ethernet traffic. 2942 Defaults to 4 if not defined. 2943 2944- CONFIG_ENV_MAX_ENTRIES 2945 2946 Maximum number of entries in the hash table that is used 2947 internally to store the environment settings. The default 2948 setting is supposed to be generous and should work in most 2949 cases. This setting can be used to tune behaviour; see 2950 lib/hashtable.c for details. 2951 2952- CONFIG_ENV_FLAGS_LIST_DEFAULT 2953- CONFIG_ENV_FLAGS_LIST_STATIC 2954 Enable validation of the values given to environment variables when 2955 calling env set. Variables can be restricted to only decimal, 2956 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2957 the variables can also be restricted to IP address or MAC address. 2958 2959 The format of the list is: 2960 type_attribute = [s|d|x|b|i|m] 2961 access_attribute = [a|r|o|c] 2962 attributes = type_attribute[access_attribute] 2963 entry = variable_name[:attributes] 2964 list = entry[,list] 2965 2966 The type attributes are: 2967 s - String (default) 2968 d - Decimal 2969 x - Hexadecimal 2970 b - Boolean ([1yYtT|0nNfF]) 2971 i - IP address 2972 m - MAC address 2973 2974 The access attributes are: 2975 a - Any (default) 2976 r - Read-only 2977 o - Write-once 2978 c - Change-default 2979 2980 - CONFIG_ENV_FLAGS_LIST_DEFAULT 2981 Define this to a list (string) to define the ".flags" 2982 environment variable in the default or embedded environment. 2983 2984 - CONFIG_ENV_FLAGS_LIST_STATIC 2985 Define this to a list (string) to define validation that 2986 should be done if an entry is not found in the ".flags" 2987 environment variable. To override a setting in the static 2988 list, simply add an entry for the same variable name to the 2989 ".flags" variable. 2990 2991 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 2992 regular expression. This allows multiple variables to define the same 2993 flags without explicitly listing them for each variable. 2994 2995- CONFIG_ENV_ACCESS_IGNORE_FORCE 2996 If defined, don't allow the -f switch to env set override variable 2997 access flags. 2998 2999The following definitions that deal with the placement and management 3000of environment data (variable area); in general, we support the 3001following configurations: 3002 3003- CONFIG_BUILD_ENVCRC: 3004 3005 Builds up envcrc with the target environment so that external utils 3006 may easily extract it and embed it in final U-Boot images. 3007 3008BE CAREFUL! The first access to the environment happens quite early 3009in U-Boot initialization (when we try to get the setting of for the 3010console baudrate). You *MUST* have mapped your NVRAM area then, or 3011U-Boot will hang. 3012 3013Please note that even with NVRAM we still use a copy of the 3014environment in RAM: we could work on NVRAM directly, but we want to 3015keep settings there always unmodified except somebody uses "saveenv" 3016to save the current settings. 3017 3018BE CAREFUL! For some special cases, the local device can not use 3019"saveenv" command. For example, the local device will get the 3020environment stored in a remote NOR flash by SRIO or PCIE link, 3021but it can not erase, write this NOR flash by SRIO or PCIE interface. 3022 3023- CONFIG_NAND_ENV_DST 3024 3025 Defines address in RAM to which the nand_spl code should copy the 3026 environment. If redundant environment is used, it will be copied to 3027 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 3028 3029Please note that the environment is read-only until the monitor 3030has been relocated to RAM and a RAM copy of the environment has been 3031created; also, when using EEPROM you will have to use env_get_f() 3032until then to read environment variables. 3033 3034The environment is protected by a CRC32 checksum. Before the monitor 3035is relocated into RAM, as a result of a bad CRC you will be working 3036with the compiled-in default environment - *silently*!!! [This is 3037necessary, because the first environment variable we need is the 3038"baudrate" setting for the console - if we have a bad CRC, we don't 3039have any device yet where we could complain.] 3040 3041Note: once the monitor has been relocated, then it will complain if 3042the default environment is used; a new CRC is computed as soon as you 3043use the "saveenv" command to store a valid environment. 3044 3045- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 3046 Echo the inverted Ethernet link state to the fault LED. 3047 3048 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 3049 also needs to be defined. 3050 3051- CONFIG_SYS_FAULT_MII_ADDR: 3052 MII address of the PHY to check for the Ethernet link state. 3053 3054- CONFIG_NS16550_MIN_FUNCTIONS: 3055 Define this if you desire to only have use of the NS16550_init 3056 and NS16550_putc functions for the serial driver located at 3057 drivers/serial/ns16550.c. This option is useful for saving 3058 space for already greatly restricted images, including but not 3059 limited to NAND_SPL configurations. 3060 3061- CONFIG_DISPLAY_BOARDINFO 3062 Display information about the board that U-Boot is running on 3063 when U-Boot starts up. The board function checkboard() is called 3064 to do this. 3065 3066- CONFIG_DISPLAY_BOARDINFO_LATE 3067 Similar to the previous option, but display this information 3068 later, once stdio is running and output goes to the LCD, if 3069 present. 3070 3071- CONFIG_BOARD_SIZE_LIMIT: 3072 Maximum size of the U-Boot image. When defined, the 3073 build system checks that the actual size does not 3074 exceed it. 3075 3076Low Level (hardware related) configuration options: 3077--------------------------------------------------- 3078 3079- CONFIG_SYS_CACHELINE_SIZE: 3080 Cache Line Size of the CPU. 3081 3082- CONFIG_SYS_CCSRBAR_DEFAULT: 3083 Default (power-on reset) physical address of CCSR on Freescale 3084 PowerPC SOCs. 3085 3086- CONFIG_SYS_CCSRBAR: 3087 Virtual address of CCSR. On a 32-bit build, this is typically 3088 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 3089 3090- CONFIG_SYS_CCSRBAR_PHYS: 3091 Physical address of CCSR. CCSR can be relocated to a new 3092 physical address, if desired. In this case, this macro should 3093 be set to that address. Otherwise, it should be set to the 3094 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 3095 is typically relocated on 36-bit builds. It is recommended 3096 that this macro be defined via the _HIGH and _LOW macros: 3097 3098 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 3099 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 3100 3101- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 3102 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 3103 either 0 (32-bit build) or 0xF (36-bit build). This macro is 3104 used in assembly code, so it must not contain typecasts or 3105 integer size suffixes (e.g. "ULL"). 3106 3107- CONFIG_SYS_CCSRBAR_PHYS_LOW: 3108 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 3109 used in assembly code, so it must not contain typecasts or 3110 integer size suffixes (e.g. "ULL"). 3111 3112- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 3113 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 3114 forced to a value that ensures that CCSR is not relocated. 3115 3116- Floppy Disk Support: 3117 CONFIG_SYS_FDC_DRIVE_NUMBER 3118 3119 the default drive number (default value 0) 3120 3121 CONFIG_SYS_ISA_IO_STRIDE 3122 3123 defines the spacing between FDC chipset registers 3124 (default value 1) 3125 3126 CONFIG_SYS_ISA_IO_OFFSET 3127 3128 defines the offset of register from address. It 3129 depends on which part of the data bus is connected to 3130 the FDC chipset. (default value 0) 3131 3132 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and 3133 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their 3134 default value. 3135 3136 if CONFIG_SYS_FDC_HW_INIT is defined, then the function 3137 fdc_hw_init() is called at the beginning of the FDC 3138 setup. fdc_hw_init() must be provided by the board 3139 source code. It is used to make hardware-dependent 3140 initializations. 3141 3142- CONFIG_IDE_AHB: 3143 Most IDE controllers were designed to be connected with PCI 3144 interface. Only few of them were designed for AHB interface. 3145 When software is doing ATA command and data transfer to 3146 IDE devices through IDE-AHB controller, some additional 3147 registers accessing to these kind of IDE-AHB controller 3148 is required. 3149 3150- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 3151 DO NOT CHANGE unless you know exactly what you're 3152 doing! (11-4) [MPC8xx systems only] 3153 3154- CONFIG_SYS_INIT_RAM_ADDR: 3155 3156 Start address of memory area that can be used for 3157 initial data and stack; please note that this must be 3158 writable memory that is working WITHOUT special 3159 initialization, i. e. you CANNOT use normal RAM which 3160 will become available only after programming the 3161 memory controller and running certain initialization 3162 sequences. 3163 3164 U-Boot uses the following memory types: 3165 - MPC8xx: IMMR (internal memory of the CPU) 3166 3167- CONFIG_SYS_GBL_DATA_OFFSET: 3168 3169 Offset of the initial data structure in the memory 3170 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 3171 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 3172 data is located at the end of the available space 3173 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 3174 GENERATED_GBL_DATA_SIZE), and the initial stack is just 3175 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 3176 CONFIG_SYS_GBL_DATA_OFFSET) downward. 3177 3178 Note: 3179 On the MPC824X (or other systems that use the data 3180 cache for initial memory) the address chosen for 3181 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 3182 point to an otherwise UNUSED address space between 3183 the top of RAM and the start of the PCI space. 3184 3185- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 3186 3187- CONFIG_SYS_OR_TIMING_SDRAM: 3188 SDRAM timing 3189 3190- CONFIG_SYS_MAMR_PTA: 3191 periodic timer for refresh 3192 3193- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 3194 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 3195 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 3196 CONFIG_SYS_BR1_PRELIM: 3197 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 3198 3199- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 3200 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 3201 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 3202 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 3203 3204- CONFIG_PCI_ENUM_ONLY 3205 Only scan through and get the devices on the buses. 3206 Don't do any setup work, presumably because someone or 3207 something has already done it, and we don't need to do it 3208 a second time. Useful for platforms that are pre-booted 3209 by coreboot or similar. 3210 3211- CONFIG_PCI_INDIRECT_BRIDGE: 3212 Enable support for indirect PCI bridges. 3213 3214- CONFIG_SYS_SRIO: 3215 Chip has SRIO or not 3216 3217- CONFIG_SRIO1: 3218 Board has SRIO 1 port available 3219 3220- CONFIG_SRIO2: 3221 Board has SRIO 2 port available 3222 3223- CONFIG_SRIO_PCIE_BOOT_MASTER 3224 Board can support master function for Boot from SRIO and PCIE 3225 3226- CONFIG_SYS_SRIOn_MEM_VIRT: 3227 Virtual Address of SRIO port 'n' memory region 3228 3229- CONFIG_SYS_SRIOn_MEM_PHYS: 3230 Physical Address of SRIO port 'n' memory region 3231 3232- CONFIG_SYS_SRIOn_MEM_SIZE: 3233 Size of SRIO port 'n' memory region 3234 3235- CONFIG_SYS_NAND_BUSWIDTH_16BIT 3236 Defined to tell the NAND controller that the NAND chip is using 3237 a 16 bit bus. 3238 Not all NAND drivers use this symbol. 3239 Example of drivers that use it: 3240 - drivers/mtd/nand/ndfc.c 3241 - drivers/mtd/nand/mxc_nand.c 3242 3243- CONFIG_SYS_NDFC_EBC0_CFG 3244 Sets the EBC0_CFG register for the NDFC. If not defined 3245 a default value will be used. 3246 3247- CONFIG_SPD_EEPROM 3248 Get DDR timing information from an I2C EEPROM. Common 3249 with pluggable memory modules such as SODIMMs 3250 3251 SPD_EEPROM_ADDRESS 3252 I2C address of the SPD EEPROM 3253 3254- CONFIG_SYS_SPD_BUS_NUM 3255 If SPD EEPROM is on an I2C bus other than the first 3256 one, specify here. Note that the value must resolve 3257 to something your driver can deal with. 3258 3259- CONFIG_SYS_DDR_RAW_TIMING 3260 Get DDR timing information from other than SPD. Common with 3261 soldered DDR chips onboard without SPD. DDR raw timing 3262 parameters are extracted from datasheet and hard-coded into 3263 header files or board specific files. 3264 3265- CONFIG_FSL_DDR_INTERACTIVE 3266 Enable interactive DDR debugging. See doc/README.fsl-ddr. 3267 3268- CONFIG_FSL_DDR_SYNC_REFRESH 3269 Enable sync of refresh for multiple controllers. 3270 3271- CONFIG_FSL_DDR_BIST 3272 Enable built-in memory test for Freescale DDR controllers. 3273 3274- CONFIG_SYS_83XX_DDR_USES_CS0 3275 Only for 83xx systems. If specified, then DDR should 3276 be configured using CS0 and CS1 instead of CS2 and CS3. 3277 3278- CONFIG_RMII 3279 Enable RMII mode for all FECs. 3280 Note that this is a global option, we can't 3281 have one FEC in standard MII mode and another in RMII mode. 3282 3283- CONFIG_CRC32_VERIFY 3284 Add a verify option to the crc32 command. 3285 The syntax is: 3286 3287 => crc32 -v <address> <count> <crc32> 3288 3289 Where address/count indicate a memory area 3290 and crc32 is the correct crc32 which the 3291 area should have. 3292 3293- CONFIG_LOOPW 3294 Add the "loopw" memory command. This only takes effect if 3295 the memory commands are activated globally (CONFIG_CMD_MEMORY). 3296 3297- CONFIG_MX_CYCLIC 3298 Add the "mdc" and "mwc" memory commands. These are cyclic 3299 "md/mw" commands. 3300 Examples: 3301 3302 => mdc.b 10 4 500 3303 This command will print 4 bytes (10,11,12,13) each 500 ms. 3304 3305 => mwc.l 100 12345678 10 3306 This command will write 12345678 to address 100 all 10 ms. 3307 3308 This only takes effect if the memory commands are activated 3309 globally (CONFIG_CMD_MEMORY). 3310 3311- CONFIG_SKIP_LOWLEVEL_INIT 3312 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 3313 low level initializations (like setting up the memory 3314 controller) are omitted and/or U-Boot does not 3315 relocate itself into RAM. 3316 3317 Normally this variable MUST NOT be defined. The only 3318 exception is when U-Boot is loaded (to RAM) by some 3319 other boot loader or by a debugger which performs 3320 these initializations itself. 3321 3322- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 3323 [ARM926EJ-S only] This allows just the call to lowlevel_init() 3324 to be skipped. The normal CP15 init (such as enabling the 3325 instruction cache) is still performed. 3326 3327- CONFIG_SPL_BUILD 3328 Modifies the behaviour of start.S when compiling a loader 3329 that is executed before the actual U-Boot. E.g. when 3330 compiling a NAND SPL. 3331 3332- CONFIG_TPL_BUILD 3333 Modifies the behaviour of start.S when compiling a loader 3334 that is executed after the SPL and before the actual U-Boot. 3335 It is loaded by the SPL. 3336 3337- CONFIG_SYS_MPC85XX_NO_RESETVEC 3338 Only for 85xx systems. If this variable is specified, the section 3339 .resetvec is not kept and the section .bootpg is placed in the 3340 previous 4k of the .text section. 3341 3342- CONFIG_ARCH_MAP_SYSMEM 3343 Generally U-Boot (and in particular the md command) uses 3344 effective address. It is therefore not necessary to regard 3345 U-Boot address as virtual addresses that need to be translated 3346 to physical addresses. However, sandbox requires this, since 3347 it maintains its own little RAM buffer which contains all 3348 addressable memory. This option causes some memory accesses 3349 to be mapped through map_sysmem() / unmap_sysmem(). 3350 3351- CONFIG_X86_RESET_VECTOR 3352 If defined, the x86 reset vector code is included. This is not 3353 needed when U-Boot is running from Coreboot. 3354 3355- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 3356 Option to disable subpage write in NAND driver 3357 driver that uses this: 3358 drivers/mtd/nand/davinci_nand.c 3359 3360Freescale QE/FMAN Firmware Support: 3361----------------------------------- 3362 3363The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 3364loading of "firmware", which is encoded in the QE firmware binary format. 3365This firmware often needs to be loaded during U-Boot booting, so macros 3366are used to identify the storage device (NOR flash, SPI, etc) and the address 3367within that device. 3368 3369- CONFIG_SYS_FMAN_FW_ADDR 3370 The address in the storage device where the FMAN microcode is located. The 3371 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3372 is also specified. 3373 3374- CONFIG_SYS_QE_FW_ADDR 3375 The address in the storage device where the QE microcode is located. The 3376 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3377 is also specified. 3378 3379- CONFIG_SYS_QE_FMAN_FW_LENGTH 3380 The maximum possible size of the firmware. The firmware binary format 3381 has a field that specifies the actual size of the firmware, but it 3382 might not be possible to read any part of the firmware unless some 3383 local storage is allocated to hold the entire firmware first. 3384 3385- CONFIG_SYS_QE_FMAN_FW_IN_NOR 3386 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 3387 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 3388 virtual address in NOR flash. 3389 3390- CONFIG_SYS_QE_FMAN_FW_IN_NAND 3391 Specifies that QE/FMAN firmware is located in NAND flash. 3392 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 3393 3394- CONFIG_SYS_QE_FMAN_FW_IN_MMC 3395 Specifies that QE/FMAN firmware is located on the primary SD/MMC 3396 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 3397 3398- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 3399 Specifies that QE/FMAN firmware is located in the remote (master) 3400 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 3401 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 3402 window->master inbound window->master LAW->the ucode address in 3403 master's memory space. 3404 3405Freescale Layerscape Management Complex Firmware Support: 3406--------------------------------------------------------- 3407The Freescale Layerscape Management Complex (MC) supports the loading of 3408"firmware". 3409This firmware often needs to be loaded during U-Boot booting, so macros 3410are used to identify the storage device (NOR flash, SPI, etc) and the address 3411within that device. 3412 3413- CONFIG_FSL_MC_ENET 3414 Enable the MC driver for Layerscape SoCs. 3415 3416Freescale Layerscape Debug Server Support: 3417------------------------------------------- 3418The Freescale Layerscape Debug Server Support supports the loading of 3419"Debug Server firmware" and triggering SP boot-rom. 3420This firmware often needs to be loaded during U-Boot booting. 3421 3422- CONFIG_SYS_MC_RSV_MEM_ALIGN 3423 Define alignment of reserved memory MC requires 3424 3425Reproducible builds 3426------------------- 3427 3428In order to achieve reproducible builds, timestamps used in the U-Boot build 3429process have to be set to a fixed value. 3430 3431This is done using the SOURCE_DATE_EPOCH environment variable. 3432SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3433option for U-Boot or an environment variable in U-Boot. 3434 3435SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3436 3437Building the Software: 3438====================== 3439 3440Building U-Boot has been tested in several native build environments 3441and in many different cross environments. Of course we cannot support 3442all possibly existing versions of cross development tools in all 3443(potentially obsolete) versions. In case of tool chain problems we 3444recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) 3445which is extensively used to build and test U-Boot. 3446 3447If you are not using a native environment, it is assumed that you 3448have GNU cross compiling tools available in your path. In this case, 3449you must set the environment variable CROSS_COMPILE in your shell. 3450Note that no changes to the Makefile or any other source files are 3451necessary. For example using the ELDK on a 4xx CPU, please enter: 3452 3453 $ CROSS_COMPILE=ppc_4xx- 3454 $ export CROSS_COMPILE 3455 3456Note: If you wish to generate Windows versions of the utilities in 3457 the tools directory you can use the MinGW toolchain 3458 (http://www.mingw.org). Set your HOST tools to the MinGW 3459 toolchain and execute 'make tools'. For example: 3460 3461 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools 3462 3463 Binaries such as tools/mkimage.exe will be created which can 3464 be executed on computers running Windows. 3465 3466U-Boot is intended to be simple to build. After installing the 3467sources you must configure U-Boot for one specific board type. This 3468is done by typing: 3469 3470 make NAME_defconfig 3471 3472where "NAME_defconfig" is the name of one of the existing configu- 3473rations; see boards.cfg for supported names. 3474 3475Note: for some board special configuration names may exist; check if 3476 additional information is available from the board vendor; for 3477 instance, the TQM823L systems are available without (standard) 3478 or with LCD support. You can select such additional "features" 3479 when choosing the configuration, i. e. 3480 3481 make TQM823L_defconfig 3482 - will configure for a plain TQM823L, i. e. no LCD support 3483 3484 make TQM823L_LCD_defconfig 3485 - will configure for a TQM823L with U-Boot console on LCD 3486 3487 etc. 3488 3489 3490Finally, type "make all", and you should get some working U-Boot 3491images ready for download to / installation on your system: 3492 3493- "u-boot.bin" is a raw binary image 3494- "u-boot" is an image in ELF binary format 3495- "u-boot.srec" is in Motorola S-Record format 3496 3497By default the build is performed locally and the objects are saved 3498in the source directory. One of the two methods can be used to change 3499this behavior and build U-Boot to some external directory: 3500 35011. Add O= to the make command line invocations: 3502 3503 make O=/tmp/build distclean 3504 make O=/tmp/build NAME_defconfig 3505 make O=/tmp/build all 3506 35072. Set environment variable KBUILD_OUTPUT to point to the desired location: 3508 3509 export KBUILD_OUTPUT=/tmp/build 3510 make distclean 3511 make NAME_defconfig 3512 make all 3513 3514Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3515variable. 3516 3517User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3518setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3519For example to treat all compiler warnings as errors: 3520 3521 make KCFLAGS=-Werror 3522 3523Please be aware that the Makefiles assume you are using GNU make, so 3524for instance on NetBSD you might need to use "gmake" instead of 3525native "make". 3526 3527 3528If the system board that you have is not listed, then you will need 3529to port U-Boot to your hardware platform. To do this, follow these 3530steps: 3531 35321. Create a new directory to hold your board specific code. Add any 3533 files you need. In your board directory, you will need at least 3534 the "Makefile" and a "<board>.c". 35352. Create a new configuration file "include/configs/<board>.h" for 3536 your board. 35373. If you're porting U-Boot to a new CPU, then also create a new 3538 directory to hold your CPU specific code. Add any files you need. 35394. Run "make <board>_defconfig" with your new name. 35405. Type "make", and you should get a working "u-boot.srec" file 3541 to be installed on your target system. 35426. Debug and solve any problems that might arise. 3543 [Of course, this last step is much harder than it sounds.] 3544 3545 3546Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3547============================================================== 3548 3549If you have modified U-Boot sources (for instance added a new board 3550or support for new devices, a new CPU, etc.) you are expected to 3551provide feedback to the other developers. The feedback normally takes 3552the form of a "patch", i. e. a context diff against a certain (latest 3553official or latest in the git repository) version of U-Boot sources. 3554 3555But before you submit such a patch, please verify that your modifi- 3556cation did not break existing code. At least make sure that *ALL* of 3557the supported boards compile WITHOUT ANY compiler warnings. To do so, 3558just run the buildman script (tools/buildman/buildman), which will 3559configure and build U-Boot for ALL supported system. Be warned, this 3560will take a while. Please see the buildman README, or run 'buildman -H' 3561for documentation. 3562 3563 3564See also "U-Boot Porting Guide" below. 3565 3566 3567Monitor Commands - Overview: 3568============================ 3569 3570go - start application at address 'addr' 3571run - run commands in an environment variable 3572bootm - boot application image from memory 3573bootp - boot image via network using BootP/TFTP protocol 3574bootz - boot zImage from memory 3575tftpboot- boot image via network using TFTP protocol 3576 and env variables "ipaddr" and "serverip" 3577 (and eventually "gatewayip") 3578tftpput - upload a file via network using TFTP protocol 3579rarpboot- boot image via network using RARP/TFTP protocol 3580diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3581loads - load S-Record file over serial line 3582loadb - load binary file over serial line (kermit mode) 3583md - memory display 3584mm - memory modify (auto-incrementing) 3585nm - memory modify (constant address) 3586mw - memory write (fill) 3587cp - memory copy 3588cmp - memory compare 3589crc32 - checksum calculation 3590i2c - I2C sub-system 3591sspi - SPI utility commands 3592base - print or set address offset 3593printenv- print environment variables 3594setenv - set environment variables 3595saveenv - save environment variables to persistent storage 3596protect - enable or disable FLASH write protection 3597erase - erase FLASH memory 3598flinfo - print FLASH memory information 3599nand - NAND memory operations (see doc/README.nand) 3600bdinfo - print Board Info structure 3601iminfo - print header information for application image 3602coninfo - print console devices and informations 3603ide - IDE sub-system 3604loop - infinite loop on address range 3605loopw - infinite write loop on address range 3606mtest - simple RAM test 3607icache - enable or disable instruction cache 3608dcache - enable or disable data cache 3609reset - Perform RESET of the CPU 3610echo - echo args to console 3611version - print monitor version 3612help - print online help 3613? - alias for 'help' 3614 3615 3616Monitor Commands - Detailed Description: 3617======================================== 3618 3619TODO. 3620 3621For now: just type "help <command>". 3622 3623 3624Environment Variables: 3625====================== 3626 3627U-Boot supports user configuration using Environment Variables which 3628can be made persistent by saving to Flash memory. 3629 3630Environment Variables are set using "setenv", printed using 3631"printenv", and saved to Flash using "saveenv". Using "setenv" 3632without a value can be used to delete a variable from the 3633environment. As long as you don't save the environment you are 3634working with an in-memory copy. In case the Flash area containing the 3635environment is erased by accident, a default environment is provided. 3636 3637Some configuration options can be set using Environment Variables. 3638 3639List of environment variables (most likely not complete): 3640 3641 baudrate - see CONFIG_BAUDRATE 3642 3643 bootdelay - see CONFIG_BOOTDELAY 3644 3645 bootcmd - see CONFIG_BOOTCOMMAND 3646 3647 bootargs - Boot arguments when booting an RTOS image 3648 3649 bootfile - Name of the image to load with TFTP 3650 3651 bootm_low - 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 lowest address allowed 3654 for use by the bootm command. See also "bootm_size" 3655 environment variable. Address defined by "bootm_low" is 3656 also the base of the initial memory mapping for the Linux 3657 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3658 bootm_mapsize. 3659 3660 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3661 This variable is given as a hexadecimal number and it 3662 defines the size of the memory region starting at base 3663 address bootm_low that is accessible by the Linux kernel 3664 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3665 as the default value if it is defined, and bootm_size is 3666 used otherwise. 3667 3668 bootm_size - Memory range available for image processing in the bootm 3669 command can be restricted. This variable is given as 3670 a hexadecimal number and defines the size of the region 3671 allowed for use by the bootm command. See also "bootm_low" 3672 environment variable. 3673 3674 updatefile - Location of the software update file on a TFTP server, used 3675 by the automatic software update feature. Please refer to 3676 documentation in doc/README.update for more details. 3677 3678 autoload - if set to "no" (any string beginning with 'n'), 3679 "bootp" will just load perform a lookup of the 3680 configuration from the BOOTP server, but not try to 3681 load any image using TFTP 3682 3683 autostart - if set to "yes", an image loaded using the "bootp", 3684 "rarpboot", "tftpboot" or "diskboot" commands will 3685 be automatically started (by internally calling 3686 "bootm") 3687 3688 If set to "no", a standalone image passed to the 3689 "bootm" command will be copied to the load address 3690 (and eventually uncompressed), but NOT be started. 3691 This can be used to load and uncompress arbitrary 3692 data. 3693 3694 fdt_high - if set this restricts the maximum address that the 3695 flattened device tree will be copied into upon boot. 3696 For example, if you have a system with 1 GB memory 3697 at physical address 0x10000000, while Linux kernel 3698 only recognizes the first 704 MB as low memory, you 3699 may need to set fdt_high as 0x3C000000 to have the 3700 device tree blob be copied to the maximum address 3701 of the 704 MB low memory, so that Linux kernel can 3702 access it during the boot procedure. 3703 3704 If this is set to the special value 0xFFFFFFFF then 3705 the fdt will not be copied at all on boot. For this 3706 to work it must reside in writable memory, have 3707 sufficient padding on the end of it for u-boot to 3708 add the information it needs into it, and the memory 3709 must be accessible by the kernel. 3710 3711 fdtcontroladdr- if set this is the address of the control flattened 3712 device tree used by U-Boot when CONFIG_OF_CONTROL is 3713 defined. 3714 3715 i2cfast - (PPC405GP|PPC405EP only) 3716 if set to 'y' configures Linux I2C driver for fast 3717 mode (400kHZ). This environment variable is used in 3718 initialization code. So, for changes to be effective 3719 it must be saved and board must be reset. 3720 3721 initrd_high - restrict positioning of initrd images: 3722 If this variable is not set, initrd images will be 3723 copied to the highest possible address in RAM; this 3724 is usually what you want since it allows for 3725 maximum initrd size. If for some reason you want to 3726 make sure that the initrd image is loaded below the 3727 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3728 variable to a value of "no" or "off" or "0". 3729 Alternatively, you can set it to a maximum upper 3730 address to use (U-Boot will still check that it 3731 does not overwrite the U-Boot stack and data). 3732 3733 For instance, when you have a system with 16 MB 3734 RAM, and want to reserve 4 MB from use by Linux, 3735 you can do this by adding "mem=12M" to the value of 3736 the "bootargs" variable. However, now you must make 3737 sure that the initrd image is placed in the first 3738 12 MB as well - this can be done with 3739 3740 setenv initrd_high 00c00000 3741 3742 If you set initrd_high to 0xFFFFFFFF, this is an 3743 indication to U-Boot that all addresses are legal 3744 for the Linux kernel, including addresses in flash 3745 memory. In this case U-Boot will NOT COPY the 3746 ramdisk at all. This may be useful to reduce the 3747 boot time on your system, but requires that this 3748 feature is supported by your Linux kernel. 3749 3750 ipaddr - IP address; needed for tftpboot command 3751 3752 loadaddr - Default load address for commands like "bootp", 3753 "rarpboot", "tftpboot", "loadb" or "diskboot" 3754 3755 loads_echo - see CONFIG_LOADS_ECHO 3756 3757 serverip - TFTP server IP address; needed for tftpboot command 3758 3759 bootretry - see CONFIG_BOOT_RETRY_TIME 3760 3761 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3762 3763 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3764 3765 ethprime - controls which interface is used first. 3766 3767 ethact - controls which interface is currently active. 3768 For example you can do the following 3769 3770 => setenv ethact FEC 3771 => ping 192.168.0.1 # traffic sent on FEC 3772 => setenv ethact SCC 3773 => ping 10.0.0.1 # traffic sent on SCC 3774 3775 ethrotate - When set to "no" U-Boot does not go through all 3776 available network interfaces. 3777 It just stays at the currently selected interface. 3778 3779 netretry - When set to "no" each network operation will 3780 either succeed or fail without retrying. 3781 When set to "once" the network operation will 3782 fail when all the available network interfaces 3783 are tried once without success. 3784 Useful on scripts which control the retry operation 3785 themselves. 3786 3787 npe_ucode - set load address for the NPE microcode 3788 3789 silent_linux - If set then Linux will be told to boot silently, by 3790 changing the console to be empty. If "yes" it will be 3791 made silent. If "no" it will not be made silent. If 3792 unset, then it will be made silent if the U-Boot console 3793 is silent. 3794 3795 tftpsrcp - If this is set, the value is used for TFTP's 3796 UDP source port. 3797 3798 tftpdstp - If this is set, the value is used for TFTP's UDP 3799 destination port instead of the Well Know Port 69. 3800 3801 tftpblocksize - Block size to use for TFTP transfers; if not set, 3802 we use the TFTP server's default block size 3803 3804 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3805 seconds, minimum value is 1000 = 1 second). Defines 3806 when a packet is considered to be lost so it has to 3807 be retransmitted. The default is 5000 = 5 seconds. 3808 Lowering this value may make downloads succeed 3809 faster in networks with high packet loss rates or 3810 with unreliable TFTP servers. 3811 3812 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3813 unit, minimum value = 0). Defines how many timeouts 3814 can happen during a single file transfer before that 3815 transfer is aborted. The default is 10, and 0 means 3816 'no timeouts allowed'. Increasing this value may help 3817 downloads succeed with high packet loss rates, or with 3818 unreliable TFTP servers or client hardware. 3819 3820 vlan - When set to a value < 4095 the traffic over 3821 Ethernet is encapsulated/received over 802.1q 3822 VLAN tagged frames. 3823 3824 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3825 Unsigned value, in milliseconds. If not set, the period will 3826 be either the default (28000), or a value based on 3827 CONFIG_NET_RETRY_COUNT, if defined. This value has 3828 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3829 3830The following image location variables contain the location of images 3831used in booting. The "Image" column gives the role of the image and is 3832not an environment variable name. The other columns are environment 3833variable names. "File Name" gives the name of the file on a TFTP 3834server, "RAM Address" gives the location in RAM the image will be 3835loaded to, and "Flash Location" gives the image's address in NOR 3836flash or offset in NAND flash. 3837 3838*Note* - these variables don't have to be defined for all boards, some 3839boards currently use other variables for these purposes, and some 3840boards use these variables for other purposes. 3841 3842Image File Name RAM Address Flash Location 3843----- --------- ----------- -------------- 3844u-boot u-boot u-boot_addr_r u-boot_addr 3845Linux kernel bootfile kernel_addr_r kernel_addr 3846device tree blob fdtfile fdt_addr_r fdt_addr 3847ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3848 3849The following environment variables may be used and automatically 3850updated by the network boot commands ("bootp" and "rarpboot"), 3851depending the information provided by your boot server: 3852 3853 bootfile - see above 3854 dnsip - IP address of your Domain Name Server 3855 dnsip2 - IP address of your secondary Domain Name Server 3856 gatewayip - IP address of the Gateway (Router) to use 3857 hostname - Target hostname 3858 ipaddr - see above 3859 netmask - Subnet Mask 3860 rootpath - Pathname of the root filesystem on the NFS server 3861 serverip - see above 3862 3863 3864There are two special Environment Variables: 3865 3866 serial# - contains hardware identification information such 3867 as type string and/or serial number 3868 ethaddr - Ethernet address 3869 3870These variables can be set only once (usually during manufacturing of 3871the board). U-Boot refuses to delete or overwrite these variables 3872once they have been set once. 3873 3874 3875Further special Environment Variables: 3876 3877 ver - Contains the U-Boot version string as printed 3878 with the "version" command. This variable is 3879 readonly (see CONFIG_VERSION_VARIABLE). 3880 3881 3882Please note that changes to some configuration parameters may take 3883only effect after the next boot (yes, that's just like Windoze :-). 3884 3885 3886Callback functions for environment variables: 3887--------------------------------------------- 3888 3889For some environment variables, the behavior of u-boot needs to change 3890when their values are changed. This functionality allows functions to 3891be associated with arbitrary variables. On creation, overwrite, or 3892deletion, the callback will provide the opportunity for some side 3893effect to happen or for the change to be rejected. 3894 3895The callbacks are named and associated with a function using the 3896U_BOOT_ENV_CALLBACK macro in your board or driver code. 3897 3898These callbacks are associated with variables in one of two ways. The 3899static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3900in the board configuration to a string that defines a list of 3901associations. The list must be in the following format: 3902 3903 entry = variable_name[:callback_name] 3904 list = entry[,list] 3905 3906If the callback name is not specified, then the callback is deleted. 3907Spaces are also allowed anywhere in the list. 3908 3909Callbacks can also be associated by defining the ".callbacks" variable 3910with the same list format above. Any association in ".callbacks" will 3911override any association in the static list. You can define 3912CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3913".callbacks" environment variable in the default or embedded environment. 3914 3915If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3916regular expression. This allows multiple variables to be connected to 3917the same callback without explicitly listing them all out. 3918 3919The signature of the callback functions is: 3920 3921 int callback(const char *name, const char *value, enum env_op op, int flags) 3922 3923* name - changed environment variable 3924* value - new value of the environment variable 3925* op - operation (create, overwrite, or delete) 3926* flags - attributes of the environment variable change, see flags H_* in 3927 include/search.h 3928 3929The return value is 0 if the variable change is accepted and 1 otherwise. 3930 3931Command Line Parsing: 3932===================== 3933 3934There are two different command line parsers available with U-Boot: 3935the old "simple" one, and the much more powerful "hush" shell: 3936 3937Old, simple command line parser: 3938-------------------------------- 3939 3940- supports environment variables (through setenv / saveenv commands) 3941- several commands on one line, separated by ';' 3942- variable substitution using "... ${name} ..." syntax 3943- special characters ('$', ';') can be escaped by prefixing with '\', 3944 for example: 3945 setenv bootcmd bootm \${address} 3946- You can also escape text by enclosing in single apostrophes, for example: 3947 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 3948 3949Hush shell: 3950----------- 3951 3952- similar to Bourne shell, with control structures like 3953 if...then...else...fi, for...do...done; while...do...done, 3954 until...do...done, ... 3955- supports environment ("global") variables (through setenv / saveenv 3956 commands) and local shell variables (through standard shell syntax 3957 "name=value"); only environment variables can be used with "run" 3958 command 3959 3960General rules: 3961-------------- 3962 3963(1) If a command line (or an environment variable executed by a "run" 3964 command) contains several commands separated by semicolon, and 3965 one of these commands fails, then the remaining commands will be 3966 executed anyway. 3967 3968(2) If you execute several variables with one call to run (i. e. 3969 calling run with a list of variables as arguments), any failing 3970 command will cause "run" to terminate, i. e. the remaining 3971 variables are not executed. 3972 3973Note for Redundant Ethernet Interfaces: 3974======================================= 3975 3976Some boards come with redundant Ethernet interfaces; U-Boot supports 3977such configurations and is capable of automatic selection of a 3978"working" interface when needed. MAC assignment works as follows: 3979 3980Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 3981MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 3982"eth1addr" (=>eth1), "eth2addr", ... 3983 3984If the network interface stores some valid MAC address (for instance 3985in SROM), this is used as default address if there is NO correspon- 3986ding setting in the environment; if the corresponding environment 3987variable is set, this overrides the settings in the card; that means: 3988 3989o If the SROM has a valid MAC address, and there is no address in the 3990 environment, the SROM's address is used. 3991 3992o If there is no valid address in the SROM, and a definition in the 3993 environment exists, then the value from the environment variable is 3994 used. 3995 3996o If both the SROM and the environment contain a MAC address, and 3997 both addresses are the same, this MAC address is used. 3998 3999o If both the SROM and the environment contain a MAC address, and the 4000 addresses differ, the value from the environment is used and a 4001 warning is printed. 4002 4003o If neither SROM nor the environment contain a MAC address, an error 4004 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 4005 a random, locally-assigned MAC is used. 4006 4007If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 4008will be programmed into hardware as part of the initialization process. This 4009may be skipped by setting the appropriate 'ethmacskip' environment variable. 4010The naming convention is as follows: 4011"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 4012 4013Image Formats: 4014============== 4015 4016U-Boot is capable of booting (and performing other auxiliary operations on) 4017images in two formats: 4018 4019New uImage format (FIT) 4020----------------------- 4021 4022Flexible and powerful format based on Flattened Image Tree -- FIT (similar 4023to Flattened Device Tree). It allows the use of images with multiple 4024components (several kernels, ramdisks, etc.), with contents protected by 4025SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 4026 4027 4028Old uImage format 4029----------------- 4030 4031Old image format is based on binary files which can be basically anything, 4032preceded by a special header; see the definitions in include/image.h for 4033details; basically, the header defines the following image properties: 4034 4035* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 4036 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 4037 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 4038 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 4039 INTEGRITY). 4040* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 4041 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 4042 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 4043* Compression Type (uncompressed, gzip, bzip2) 4044* Load Address 4045* Entry Point 4046* Image Name 4047* Image Timestamp 4048 4049The header is marked by a special Magic Number, and both the header 4050and the data portions of the image are secured against corruption by 4051CRC32 checksums. 4052 4053 4054Linux Support: 4055============== 4056 4057Although U-Boot should support any OS or standalone application 4058easily, the main focus has always been on Linux during the design of 4059U-Boot. 4060 4061U-Boot includes many features that so far have been part of some 4062special "boot loader" code within the Linux kernel. Also, any 4063"initrd" images to be used are no longer part of one big Linux image; 4064instead, kernel and "initrd" are separate images. This implementation 4065serves several purposes: 4066 4067- the same features can be used for other OS or standalone 4068 applications (for instance: using compressed images to reduce the 4069 Flash memory footprint) 4070 4071- it becomes much easier to port new Linux kernel versions because 4072 lots of low-level, hardware dependent stuff are done by U-Boot 4073 4074- the same Linux kernel image can now be used with different "initrd" 4075 images; of course this also means that different kernel images can 4076 be run with the same "initrd". This makes testing easier (you don't 4077 have to build a new "zImage.initrd" Linux image when you just 4078 change a file in your "initrd"). Also, a field-upgrade of the 4079 software is easier now. 4080 4081 4082Linux HOWTO: 4083============ 4084 4085Porting Linux to U-Boot based systems: 4086--------------------------------------- 4087 4088U-Boot cannot save you from doing all the necessary modifications to 4089configure the Linux device drivers for use with your target hardware 4090(no, we don't intend to provide a full virtual machine interface to 4091Linux :-). 4092 4093But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 4094 4095Just make sure your machine specific header file (for instance 4096include/asm-ppc/tqm8xx.h) includes the same definition of the Board 4097Information structure as we define in include/asm-<arch>/u-boot.h, 4098and make sure that your definition of IMAP_ADDR uses the same value 4099as your U-Boot configuration in CONFIG_SYS_IMMR. 4100 4101Note that U-Boot now has a driver model, a unified model for drivers. 4102If you are adding a new driver, plumb it into driver model. If there 4103is no uclass available, you are encouraged to create one. See 4104doc/driver-model. 4105 4106 4107Configuring the Linux kernel: 4108----------------------------- 4109 4110No specific requirements for U-Boot. Make sure you have some root 4111device (initial ramdisk, NFS) for your target system. 4112 4113 4114Building a Linux Image: 4115----------------------- 4116 4117With U-Boot, "normal" build targets like "zImage" or "bzImage" are 4118not used. If you use recent kernel source, a new build target 4119"uImage" will exist which automatically builds an image usable by 4120U-Boot. Most older kernels also have support for a "pImage" target, 4121which was introduced for our predecessor project PPCBoot and uses a 4122100% compatible format. 4123 4124Example: 4125 4126 make TQM850L_defconfig 4127 make oldconfig 4128 make dep 4129 make uImage 4130 4131The "uImage" build target uses a special tool (in 'tools/mkimage') to 4132encapsulate a compressed Linux kernel image with header information, 4133CRC32 checksum etc. for use with U-Boot. This is what we are doing: 4134 4135* build a standard "vmlinux" kernel image (in ELF binary format): 4136 4137* convert the kernel into a raw binary image: 4138 4139 ${CROSS_COMPILE}-objcopy -O binary \ 4140 -R .note -R .comment \ 4141 -S vmlinux linux.bin 4142 4143* compress the binary image: 4144 4145 gzip -9 linux.bin 4146 4147* package compressed binary image for U-Boot: 4148 4149 mkimage -A ppc -O linux -T kernel -C gzip \ 4150 -a 0 -e 0 -n "Linux Kernel Image" \ 4151 -d linux.bin.gz uImage 4152 4153 4154The "mkimage" tool can also be used to create ramdisk images for use 4155with U-Boot, either separated from the Linux kernel image, or 4156combined into one file. "mkimage" encapsulates the images with a 64 4157byte header containing information about target architecture, 4158operating system, image type, compression method, entry points, time 4159stamp, CRC32 checksums, etc. 4160 4161"mkimage" can be called in two ways: to verify existing images and 4162print the header information, or to build new images. 4163 4164In the first form (with "-l" option) mkimage lists the information 4165contained in the header of an existing U-Boot image; this includes 4166checksum verification: 4167 4168 tools/mkimage -l image 4169 -l ==> list image header information 4170 4171The second form (with "-d" option) is used to build a U-Boot image 4172from a "data file" which is used as image payload: 4173 4174 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 4175 -n name -d data_file image 4176 -A ==> set architecture to 'arch' 4177 -O ==> set operating system to 'os' 4178 -T ==> set image type to 'type' 4179 -C ==> set compression type 'comp' 4180 -a ==> set load address to 'addr' (hex) 4181 -e ==> set entry point to 'ep' (hex) 4182 -n ==> set image name to 'name' 4183 -d ==> use image data from 'datafile' 4184 4185Right now, all Linux kernels for PowerPC systems use the same load 4186address (0x00000000), but the entry point address depends on the 4187kernel version: 4188 4189- 2.2.x kernels have the entry point at 0x0000000C, 4190- 2.3.x and later kernels have the entry point at 0x00000000. 4191 4192So a typical call to build a U-Boot image would read: 4193 4194 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4195 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 4196 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 4197 > examples/uImage.TQM850L 4198 Image Name: 2.4.4 kernel for TQM850L 4199 Created: Wed Jul 19 02:34:59 2000 4200 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4201 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4202 Load Address: 0x00000000 4203 Entry Point: 0x00000000 4204 4205To verify the contents of the image (or check for corruption): 4206 4207 -> tools/mkimage -l examples/uImage.TQM850L 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 (gzip compressed) 4211 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4212 Load Address: 0x00000000 4213 Entry Point: 0x00000000 4214 4215NOTE: for embedded systems where boot time is critical you can trade 4216speed for memory and install an UNCOMPRESSED image instead: this 4217needs more space in Flash, but boots much faster since it does not 4218need to be uncompressed: 4219 4220 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 4221 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4222 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 4223 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 4224 > examples/uImage.TQM850L-uncompressed 4225 Image Name: 2.4.4 kernel for TQM850L 4226 Created: Wed Jul 19 02:34:59 2000 4227 Image Type: PowerPC Linux Kernel Image (uncompressed) 4228 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 4229 Load Address: 0x00000000 4230 Entry Point: 0x00000000 4231 4232 4233Similar you can build U-Boot images from a 'ramdisk.image.gz' file 4234when your kernel is intended to use an initial ramdisk: 4235 4236 -> tools/mkimage -n 'Simple Ramdisk Image' \ 4237 > -A ppc -O linux -T ramdisk -C gzip \ 4238 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 4239 Image Name: Simple Ramdisk Image 4240 Created: Wed Jan 12 14:01:50 2000 4241 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4242 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 4243 Load Address: 0x00000000 4244 Entry Point: 0x00000000 4245 4246The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i" 4247option performs the converse operation of the mkimage's second form (the "-d" 4248option). Given an image built by mkimage, the dumpimage extracts a "data file" 4249from the image: 4250 4251 tools/dumpimage -i image -T type -p position data_file 4252 -i ==> extract from the 'image' a specific 'data_file' 4253 -T ==> set image type to 'type' 4254 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image' 4255 4256 4257Installing a Linux Image: 4258------------------------- 4259 4260To downloading a U-Boot image over the serial (console) interface, 4261you must convert the image to S-Record format: 4262 4263 objcopy -I binary -O srec examples/image examples/image.srec 4264 4265The 'objcopy' does not understand the information in the U-Boot 4266image header, so the resulting S-Record file will be relative to 4267address 0x00000000. To load it to a given address, you need to 4268specify the target address as 'offset' parameter with the 'loads' 4269command. 4270 4271Example: install the image to address 0x40100000 (which on the 4272TQM8xxL is in the first Flash bank): 4273 4274 => erase 40100000 401FFFFF 4275 4276 .......... done 4277 Erased 8 sectors 4278 4279 => loads 40100000 4280 ## Ready for S-Record download ... 4281 ~>examples/image.srec 4282 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 4283 ... 4284 15989 15990 15991 15992 4285 [file transfer complete] 4286 [connected] 4287 ## Start Addr = 0x00000000 4288 4289 4290You can check the success of the download using the 'iminfo' command; 4291this includes a checksum verification so you can be sure no data 4292corruption happened: 4293 4294 => imi 40100000 4295 4296 ## Checking Image at 40100000 ... 4297 Image Name: 2.2.13 for initrd on TQM850L 4298 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4299 Data Size: 335725 Bytes = 327 kB = 0 MB 4300 Load Address: 00000000 4301 Entry Point: 0000000c 4302 Verifying Checksum ... OK 4303 4304 4305Boot Linux: 4306----------- 4307 4308The "bootm" command is used to boot an application that is stored in 4309memory (RAM or Flash). In case of a Linux kernel image, the contents 4310of the "bootargs" environment variable is passed to the kernel as 4311parameters. You can check and modify this variable using the 4312"printenv" and "setenv" commands: 4313 4314 4315 => printenv bootargs 4316 bootargs=root=/dev/ram 4317 4318 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4319 4320 => printenv bootargs 4321 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4322 4323 => bootm 40020000 4324 ## Booting Linux kernel at 40020000 ... 4325 Image Name: 2.2.13 for NFS on TQM850L 4326 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4327 Data Size: 381681 Bytes = 372 kB = 0 MB 4328 Load Address: 00000000 4329 Entry Point: 0000000c 4330 Verifying Checksum ... OK 4331 Uncompressing Kernel Image ... OK 4332 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 4333 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4334 time_init: decrementer frequency = 187500000/60 4335 Calibrating delay loop... 49.77 BogoMIPS 4336 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 4337 ... 4338 4339If you want to boot a Linux kernel with initial RAM disk, you pass 4340the memory addresses of both the kernel and the initrd image (PPBCOOT 4341format!) to the "bootm" command: 4342 4343 => imi 40100000 40200000 4344 4345 ## Checking Image 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 4353 ## Checking 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 4361 => bootm 40100000 40200000 4362 ## Booting Linux kernel at 40100000 ... 4363 Image Name: 2.2.13 for initrd on TQM850L 4364 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4365 Data Size: 335725 Bytes = 327 kB = 0 MB 4366 Load Address: 00000000 4367 Entry Point: 0000000c 4368 Verifying Checksum ... OK 4369 Uncompressing Kernel Image ... OK 4370 ## Loading RAMDisk Image at 40200000 ... 4371 Image Name: Simple Ramdisk Image 4372 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4373 Data Size: 566530 Bytes = 553 kB = 0 MB 4374 Load Address: 00000000 4375 Entry Point: 00000000 4376 Verifying Checksum ... OK 4377 Loading Ramdisk ... OK 4378 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 4379 Boot arguments: root=/dev/ram 4380 time_init: decrementer frequency = 187500000/60 4381 Calibrating delay loop... 49.77 BogoMIPS 4382 ... 4383 RAMDISK: Compressed image found at block 0 4384 VFS: Mounted root (ext2 filesystem). 4385 4386 bash# 4387 4388Boot Linux and pass a flat device tree: 4389----------- 4390 4391First, U-Boot must be compiled with the appropriate defines. See the section 4392titled "Linux Kernel Interface" above for a more in depth explanation. The 4393following is an example of how to start a kernel and pass an updated 4394flat device tree: 4395 4396=> print oftaddr 4397oftaddr=0x300000 4398=> print oft 4399oft=oftrees/mpc8540ads.dtb 4400=> tftp $oftaddr $oft 4401Speed: 1000, full duplex 4402Using TSEC0 device 4403TFTP from server 192.168.1.1; our IP address is 192.168.1.101 4404Filename 'oftrees/mpc8540ads.dtb'. 4405Load address: 0x300000 4406Loading: # 4407done 4408Bytes transferred = 4106 (100a hex) 4409=> tftp $loadaddr $bootfile 4410Speed: 1000, full duplex 4411Using TSEC0 device 4412TFTP from server 192.168.1.1; our IP address is 192.168.1.2 4413Filename 'uImage'. 4414Load address: 0x200000 4415Loading:############ 4416done 4417Bytes transferred = 1029407 (fb51f hex) 4418=> print loadaddr 4419loadaddr=200000 4420=> print oftaddr 4421oftaddr=0x300000 4422=> bootm $loadaddr - $oftaddr 4423## Booting image at 00200000 ... 4424 Image Name: Linux-2.6.17-dirty 4425 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4426 Data Size: 1029343 Bytes = 1005.2 kB 4427 Load Address: 00000000 4428 Entry Point: 00000000 4429 Verifying Checksum ... OK 4430 Uncompressing Kernel Image ... OK 4431Booting using flat device tree at 0x300000 4432Using MPC85xx ADS machine description 4433Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 4434[snip] 4435 4436 4437More About U-Boot Image Types: 4438------------------------------ 4439 4440U-Boot supports the following image types: 4441 4442 "Standalone Programs" are directly runnable in the environment 4443 provided by U-Boot; it is expected that (if they behave 4444 well) you can continue to work in U-Boot after return from 4445 the Standalone Program. 4446 "OS Kernel Images" are usually images of some Embedded OS which 4447 will take over control completely. Usually these programs 4448 will install their own set of exception handlers, device 4449 drivers, set up the MMU, etc. - this means, that you cannot 4450 expect to re-enter U-Boot except by resetting the CPU. 4451 "RAMDisk Images" are more or less just data blocks, and their 4452 parameters (address, size) are passed to an OS kernel that is 4453 being started. 4454 "Multi-File Images" contain several images, typically an OS 4455 (Linux) kernel image and one or more data images like 4456 RAMDisks. This construct is useful for instance when you want 4457 to boot over the network using BOOTP etc., where the boot 4458 server provides just a single image file, but you want to get 4459 for instance an OS kernel and a RAMDisk image. 4460 4461 "Multi-File Images" start with a list of image sizes, each 4462 image size (in bytes) specified by an "uint32_t" in network 4463 byte order. This list is terminated by an "(uint32_t)0". 4464 Immediately after the terminating 0 follow the images, one by 4465 one, all aligned on "uint32_t" boundaries (size rounded up to 4466 a multiple of 4 bytes). 4467 4468 "Firmware Images" are binary images containing firmware (like 4469 U-Boot or FPGA images) which usually will be programmed to 4470 flash memory. 4471 4472 "Script files" are command sequences that will be executed by 4473 U-Boot's command interpreter; this feature is especially 4474 useful when you configure U-Boot to use a real shell (hush) 4475 as command interpreter. 4476 4477Booting the Linux zImage: 4478------------------------- 4479 4480On some platforms, it's possible to boot Linux zImage. This is done 4481using the "bootz" command. The syntax of "bootz" command is the same 4482as the syntax of "bootm" command. 4483 4484Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4485kernel with raw initrd images. The syntax is slightly different, the 4486address of the initrd must be augmented by it's size, in the following 4487format: "<initrd addres>:<initrd size>". 4488 4489 4490Standalone HOWTO: 4491================= 4492 4493One of the features of U-Boot is that you can dynamically load and 4494run "standalone" applications, which can use some resources of 4495U-Boot like console I/O functions or interrupt services. 4496 4497Two simple examples are included with the sources: 4498 4499"Hello World" Demo: 4500------------------- 4501 4502'examples/hello_world.c' contains a small "Hello World" Demo 4503application; it is automatically compiled when you build U-Boot. 4504It's configured to run at address 0x00040004, so you can play with it 4505like that: 4506 4507 => loads 4508 ## Ready for S-Record download ... 4509 ~>examples/hello_world.srec 4510 1 2 3 4 5 6 7 8 9 10 11 ... 4511 [file transfer complete] 4512 [connected] 4513 ## Start Addr = 0x00040004 4514 4515 => go 40004 Hello World! This is a test. 4516 ## Starting application at 0x00040004 ... 4517 Hello World 4518 argc = 7 4519 argv[0] = "40004" 4520 argv[1] = "Hello" 4521 argv[2] = "World!" 4522 argv[3] = "This" 4523 argv[4] = "is" 4524 argv[5] = "a" 4525 argv[6] = "test." 4526 argv[7] = "<NULL>" 4527 Hit any key to exit ... 4528 4529 ## Application terminated, rc = 0x0 4530 4531Another example, which demonstrates how to register a CPM interrupt 4532handler with the U-Boot code, can be found in 'examples/timer.c'. 4533Here, a CPM timer is set up to generate an interrupt every second. 4534The interrupt service routine is trivial, just printing a '.' 4535character, but this is just a demo program. The application can be 4536controlled by the following keys: 4537 4538 ? - print current values og the CPM Timer registers 4539 b - enable interrupts and start timer 4540 e - stop timer and disable interrupts 4541 q - quit application 4542 4543 => loads 4544 ## Ready for S-Record download ... 4545 ~>examples/timer.srec 4546 1 2 3 4 5 6 7 8 9 10 11 ... 4547 [file transfer complete] 4548 [connected] 4549 ## Start Addr = 0x00040004 4550 4551 => go 40004 4552 ## Starting application at 0x00040004 ... 4553 TIMERS=0xfff00980 4554 Using timer 1 4555 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4556 4557Hit 'b': 4558 [q, b, e, ?] Set interval 1000000 us 4559 Enabling timer 4560Hit '?': 4561 [q, b, e, ?] ........ 4562 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4563Hit '?': 4564 [q, b, e, ?] . 4565 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4566Hit '?': 4567 [q, b, e, ?] . 4568 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4569Hit '?': 4570 [q, b, e, ?] . 4571 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4572Hit 'e': 4573 [q, b, e, ?] ...Stopping timer 4574Hit 'q': 4575 [q, b, e, ?] ## Application terminated, rc = 0x0 4576 4577 4578Minicom warning: 4579================ 4580 4581Over time, many people have reported problems when trying to use the 4582"minicom" terminal emulation program for serial download. I (wd) 4583consider minicom to be broken, and recommend not to use it. Under 4584Unix, I recommend to use C-Kermit for general purpose use (and 4585especially for kermit binary protocol download ("loadb" command), and 4586use "cu" for S-Record download ("loads" command). See 4587http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4588for help with kermit. 4589 4590 4591Nevertheless, if you absolutely want to use it try adding this 4592configuration to your "File transfer protocols" section: 4593 4594 Name Program Name U/D FullScr IO-Red. Multi 4595 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4596 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4597 4598 4599NetBSD Notes: 4600============= 4601 4602Starting at version 0.9.2, U-Boot supports NetBSD both as host 4603(build U-Boot) and target system (boots NetBSD/mpc8xx). 4604 4605Building requires a cross environment; it is known to work on 4606NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4607need gmake since the Makefiles are not compatible with BSD make). 4608Note that the cross-powerpc package does not install include files; 4609attempting to build U-Boot will fail because <machine/ansi.h> is 4610missing. This file has to be installed and patched manually: 4611 4612 # cd /usr/pkg/cross/powerpc-netbsd/include 4613 # mkdir powerpc 4614 # ln -s powerpc machine 4615 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4616 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4617 4618Native builds *don't* work due to incompatibilities between native 4619and U-Boot include files. 4620 4621Booting assumes that (the first part of) the image booted is a 4622stage-2 loader which in turn loads and then invokes the kernel 4623proper. Loader sources will eventually appear in the NetBSD source 4624tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4625meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4626 4627 4628Implementation Internals: 4629========================= 4630 4631The following is not intended to be a complete description of every 4632implementation detail. However, it should help to understand the 4633inner workings of U-Boot and make it easier to port it to custom 4634hardware. 4635 4636 4637Initial Stack, Global Data: 4638--------------------------- 4639 4640The implementation of U-Boot is complicated by the fact that U-Boot 4641starts running out of ROM (flash memory), usually without access to 4642system RAM (because the memory controller is not initialized yet). 4643This means that we don't have writable Data or BSS segments, and BSS 4644is not initialized as zero. To be able to get a C environment working 4645at all, we have to allocate at least a minimal stack. Implementation 4646options for this are defined and restricted by the CPU used: Some CPU 4647models provide on-chip memory (like the IMMR area on MPC8xx and 4648MPC826x processors), on others (parts of) the data cache can be 4649locked as (mis-) used as memory, etc. 4650 4651 Chris Hallinan posted a good summary of these issues to the 4652 U-Boot mailing list: 4653 4654 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4655 From: "Chris Hallinan" <clh@net1plus.com> 4656 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4657 ... 4658 4659 Correct me if I'm wrong, folks, but the way I understand it 4660 is this: Using DCACHE as initial RAM for Stack, etc, does not 4661 require any physical RAM backing up the cache. The cleverness 4662 is that the cache is being used as a temporary supply of 4663 necessary storage before the SDRAM controller is setup. It's 4664 beyond the scope of this list to explain the details, but you 4665 can see how this works by studying the cache architecture and 4666 operation in the architecture and processor-specific manuals. 4667 4668 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4669 is another option for the system designer to use as an 4670 initial stack/RAM area prior to SDRAM being available. Either 4671 option should work for you. Using CS 4 should be fine if your 4672 board designers haven't used it for something that would 4673 cause you grief during the initial boot! It is frequently not 4674 used. 4675 4676 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4677 with your processor/board/system design. The default value 4678 you will find in any recent u-boot distribution in 4679 walnut.h should work for you. I'd set it to a value larger 4680 than your SDRAM module. If you have a 64MB SDRAM module, set 4681 it above 400_0000. Just make sure your board has no resources 4682 that are supposed to respond to that address! That code in 4683 start.S has been around a while and should work as is when 4684 you get the config right. 4685 4686 -Chris Hallinan 4687 DS4.COM, Inc. 4688 4689It is essential to remember this, since it has some impact on the C 4690code for the initialization procedures: 4691 4692* Initialized global data (data segment) is read-only. Do not attempt 4693 to write it. 4694 4695* Do not use any uninitialized global data (or implicitly initialized 4696 as zero data - BSS segment) at all - this is undefined, initiali- 4697 zation is performed later (when relocating to RAM). 4698 4699* Stack space is very limited. Avoid big data buffers or things like 4700 that. 4701 4702Having only the stack as writable memory limits means we cannot use 4703normal global data to share information between the code. But it 4704turned out that the implementation of U-Boot can be greatly 4705simplified by making a global data structure (gd_t) available to all 4706functions. We could pass a pointer to this data as argument to _all_ 4707functions, but this would bloat the code. Instead we use a feature of 4708the GCC compiler (Global Register Variables) to share the data: we 4709place a pointer (gd) to the global data into a register which we 4710reserve for this purpose. 4711 4712When choosing a register for such a purpose we are restricted by the 4713relevant (E)ABI specifications for the current architecture, and by 4714GCC's implementation. 4715 4716For PowerPC, the following registers have specific use: 4717 R1: stack pointer 4718 R2: reserved for system use 4719 R3-R4: parameter passing and return values 4720 R5-R10: parameter passing 4721 R13: small data area pointer 4722 R30: GOT pointer 4723 R31: frame pointer 4724 4725 (U-Boot also uses R12 as internal GOT pointer. r12 4726 is a volatile register so r12 needs to be reset when 4727 going back and forth between asm and C) 4728 4729 ==> U-Boot will use R2 to hold a pointer to the global data 4730 4731 Note: on PPC, we could use a static initializer (since the 4732 address of the global data structure is known at compile time), 4733 but it turned out that reserving a register results in somewhat 4734 smaller code - although the code savings are not that big (on 4735 average for all boards 752 bytes for the whole U-Boot image, 4736 624 text + 127 data). 4737 4738On ARM, the following registers are used: 4739 4740 R0: function argument word/integer result 4741 R1-R3: function argument word 4742 R9: platform specific 4743 R10: stack limit (used only if stack checking is enabled) 4744 R11: argument (frame) pointer 4745 R12: temporary workspace 4746 R13: stack pointer 4747 R14: link register 4748 R15: program counter 4749 4750 ==> U-Boot will use R9 to hold a pointer to the global data 4751 4752 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4753 4754On Nios II, the ABI is documented here: 4755 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4756 4757 ==> U-Boot will use gp to hold a pointer to the global data 4758 4759 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4760 to access small data sections, so gp is free. 4761 4762On NDS32, the following registers are used: 4763 4764 R0-R1: argument/return 4765 R2-R5: argument 4766 R15: temporary register for assembler 4767 R16: trampoline register 4768 R28: frame pointer (FP) 4769 R29: global pointer (GP) 4770 R30: link register (LP) 4771 R31: stack pointer (SP) 4772 PC: program counter (PC) 4773 4774 ==> U-Boot will use R10 to hold a pointer to the global data 4775 4776NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4777or current versions of GCC may "optimize" the code too much. 4778 4779On RISC-V, the following registers are used: 4780 4781 x0: hard-wired zero (zero) 4782 x1: return address (ra) 4783 x2: stack pointer (sp) 4784 x3: global pointer (gp) 4785 x4: thread pointer (tp) 4786 x5: link register (t0) 4787 x8: frame pointer (fp) 4788 x10-x11: arguments/return values (a0-1) 4789 x12-x17: arguments (a2-7) 4790 x28-31: temporaries (t3-6) 4791 pc: program counter (pc) 4792 4793 ==> U-Boot will use gp to hold a pointer to the global data 4794 4795Memory Management: 4796------------------ 4797 4798U-Boot runs in system state and uses physical addresses, i.e. the 4799MMU is not used either for address mapping nor for memory protection. 4800 4801The available memory is mapped to fixed addresses using the memory 4802controller. In this process, a contiguous block is formed for each 4803memory type (Flash, SDRAM, SRAM), even when it consists of several 4804physical memory banks. 4805 4806U-Boot is installed in the first 128 kB of the first Flash bank (on 4807TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4808booting and sizing and initializing DRAM, the code relocates itself 4809to the upper end of DRAM. Immediately below the U-Boot code some 4810memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4811configuration setting]. Below that, a structure with global Board 4812Info data is placed, followed by the stack (growing downward). 4813 4814Additionally, some exception handler code is copied to the low 8 kB 4815of DRAM (0x00000000 ... 0x00001FFF). 4816 4817So a typical memory configuration with 16 MB of DRAM could look like 4818this: 4819 4820 0x0000 0000 Exception Vector code 4821 : 4822 0x0000 1FFF 4823 0x0000 2000 Free for Application Use 4824 : 4825 : 4826 4827 : 4828 : 4829 0x00FB FF20 Monitor Stack (Growing downward) 4830 0x00FB FFAC Board Info Data and permanent copy of global data 4831 0x00FC 0000 Malloc Arena 4832 : 4833 0x00FD FFFF 4834 0x00FE 0000 RAM Copy of Monitor Code 4835 ... eventually: LCD or video framebuffer 4836 ... eventually: pRAM (Protected RAM - unchanged by reset) 4837 0x00FF FFFF [End of RAM] 4838 4839 4840System Initialization: 4841---------------------- 4842 4843In the reset configuration, U-Boot starts at the reset entry point 4844(on most PowerPC systems at address 0x00000100). Because of the reset 4845configuration for CS0# this is a mirror of the on board Flash memory. 4846To be able to re-map memory U-Boot then jumps to its link address. 4847To be able to implement the initialization code in C, a (small!) 4848initial stack is set up in the internal Dual Ported RAM (in case CPUs 4849which provide such a feature like), or in a locked part of the data 4850cache. After that, U-Boot initializes the CPU core, the caches and 4851the SIU. 4852 4853Next, all (potentially) available memory banks are mapped using a 4854preliminary mapping. For example, we put them on 512 MB boundaries 4855(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4856on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4857programmed for SDRAM access. Using the temporary configuration, a 4858simple memory test is run that determines the size of the SDRAM 4859banks. 4860 4861When there is more than one SDRAM bank, and the banks are of 4862different size, the largest is mapped first. For equal size, the first 4863bank (CS2#) is mapped first. The first mapping is always for address 48640x00000000, with any additional banks following immediately to create 4865contiguous memory starting from 0. 4866 4867Then, the monitor installs itself at the upper end of the SDRAM area 4868and allocates memory for use by malloc() and for the global Board 4869Info data; also, the exception vector code is copied to the low RAM 4870pages, and the final stack is set up. 4871 4872Only after this relocation will you have a "normal" C environment; 4873until that you are restricted in several ways, mostly because you are 4874running from ROM, and because the code will have to be relocated to a 4875new address in RAM. 4876 4877 4878U-Boot Porting Guide: 4879---------------------- 4880 4881[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4882list, October 2002] 4883 4884 4885int main(int argc, char *argv[]) 4886{ 4887 sighandler_t no_more_time; 4888 4889 signal(SIGALRM, no_more_time); 4890 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4891 4892 if (available_money > available_manpower) { 4893 Pay consultant to port U-Boot; 4894 return 0; 4895 } 4896 4897 Download latest U-Boot source; 4898 4899 Subscribe to u-boot mailing list; 4900 4901 if (clueless) 4902 email("Hi, I am new to U-Boot, how do I get started?"); 4903 4904 while (learning) { 4905 Read the README file in the top level directory; 4906 Read http://www.denx.de/twiki/bin/view/DULG/Manual; 4907 Read applicable doc/*.README; 4908 Read the source, Luke; 4909 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4910 } 4911 4912 if (available_money > toLocalCurrency ($2500)) 4913 Buy a BDI3000; 4914 else 4915 Add a lot of aggravation and time; 4916 4917 if (a similar board exists) { /* hopefully... */ 4918 cp -a board/<similar> board/<myboard> 4919 cp include/configs/<similar>.h include/configs/<myboard>.h 4920 } else { 4921 Create your own board support subdirectory; 4922 Create your own board include/configs/<myboard>.h file; 4923 } 4924 Edit new board/<myboard> files 4925 Edit new include/configs/<myboard>.h 4926 4927 while (!accepted) { 4928 while (!running) { 4929 do { 4930 Add / modify source code; 4931 } until (compiles); 4932 Debug; 4933 if (clueless) 4934 email("Hi, I am having problems..."); 4935 } 4936 Send patch file to the U-Boot email list; 4937 if (reasonable critiques) 4938 Incorporate improvements from email list code review; 4939 else 4940 Defend code as written; 4941 } 4942 4943 return 0; 4944} 4945 4946void no_more_time (int sig) 4947{ 4948 hire_a_guru(); 4949} 4950 4951 4952Coding Standards: 4953----------------- 4954 4955All contributions to U-Boot should conform to the Linux kernel 4956coding style; see the kernel coding style guide at 4957https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4958script "scripts/Lindent" in your Linux kernel source directory. 4959 4960Source files originating from a different project (for example the 4961MTD subsystem) are generally exempt from these guidelines and are not 4962reformatted to ease subsequent migration to newer versions of those 4963sources. 4964 4965Please note that U-Boot is implemented in C (and to some small parts in 4966Assembler); no C++ is used, so please do not use C++ style comments (//) 4967in your code. 4968 4969Please also stick to the following formatting rules: 4970- remove any trailing white space 4971- use TAB characters for indentation and vertical alignment, not spaces 4972- make sure NOT to use DOS '\r\n' line feeds 4973- do not add more than 2 consecutive empty lines to source files 4974- do not add trailing empty lines to source files 4975 4976Submissions which do not conform to the standards may be returned 4977with a request to reformat the changes. 4978 4979 4980Submitting Patches: 4981------------------- 4982 4983Since the number of patches for U-Boot is growing, we need to 4984establish some rules. Submissions which do not conform to these rules 4985may be rejected, even when they contain important and valuable stuff. 4986 4987Please see http://www.denx.de/wiki/U-Boot/Patches for details. 4988 4989Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 4990see https://lists.denx.de/listinfo/u-boot 4991 4992When you send a patch, please include the following information with 4993it: 4994 4995* For bug fixes: a description of the bug and how your patch fixes 4996 this bug. Please try to include a way of demonstrating that the 4997 patch actually fixes something. 4998 4999* For new features: a description of the feature and your 5000 implementation. 5001 5002* A CHANGELOG entry as plaintext (separate from the patch) 5003 5004* For major contributions, add a MAINTAINERS file with your 5005 information and associated file and directory references. 5006 5007* When you add support for a new board, don't forget to add a 5008 maintainer e-mail address to the boards.cfg file, too. 5009 5010* If your patch adds new configuration options, don't forget to 5011 document these in the README file. 5012 5013* The patch itself. If you are using git (which is *strongly* 5014 recommended) you can easily generate the patch using the 5015 "git format-patch". If you then use "git send-email" to send it to 5016 the U-Boot mailing list, you will avoid most of the common problems 5017 with some other mail clients. 5018 5019 If you cannot use git, use "diff -purN OLD NEW". If your version of 5020 diff does not support these options, then get the latest version of 5021 GNU diff. 5022 5023 The current directory when running this command shall be the parent 5024 directory of the U-Boot source tree (i. e. please make sure that 5025 your patch includes sufficient directory information for the 5026 affected files). 5027 5028 We prefer patches as plain text. MIME attachments are discouraged, 5029 and compressed attachments must not be used. 5030 5031* If one logical set of modifications affects or creates several 5032 files, all these changes shall be submitted in a SINGLE patch file. 5033 5034* Changesets that contain different, unrelated modifications shall be 5035 submitted as SEPARATE patches, one patch per changeset. 5036 5037 5038Notes: 5039 5040* Before sending the patch, run the buildman script on your patched 5041 source tree and make sure that no errors or warnings are reported 5042 for any of the boards. 5043 5044* Keep your modifications to the necessary minimum: A patch 5045 containing several unrelated changes or arbitrary reformats will be 5046 returned with a request to re-formatting / split it. 5047 5048* If you modify existing code, make sure that your new code does not 5049 add to the memory footprint of the code ;-) Small is beautiful! 5050 When adding new features, these should compile conditionally only 5051 (using #ifdef), and the resulting code with the new feature 5052 disabled must not need more memory than the old code without your 5053 modification. 5054 5055* Remember that there is a size limit of 100 kB per message on the 5056 u-boot mailing list. Bigger patches will be moderated. If they are 5057 reasonable and not too big, they will be acknowledged. But patches 5058 bigger than the size limit should be avoided. 5059