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- Serial Download Echo Mode: 691 CONFIG_LOADS_ECHO 692 If defined to 1, all characters received during a 693 serial download (using the "loads" command) are 694 echoed back. This might be needed by some terminal 695 emulations (like "cu"), but may as well just take 696 time on others. This setting #define's the initial 697 value of the "loads_echo" environment variable. 698 699- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined) 700 CONFIG_KGDB_BAUDRATE 701 Select one of the baudrates listed in 702 CONFIG_SYS_BAUDRATE_TABLE, see below. 703 704- Removal of commands 705 If no commands are needed to boot, you can disable 706 CONFIG_CMDLINE to remove them. In this case, the command line 707 will not be available, and when U-Boot wants to execute the 708 boot command (on start-up) it will call board_run_command() 709 instead. This can reduce image size significantly for very 710 simple boot procedures. 711 712- Regular expression support: 713 CONFIG_REGEX 714 If this variable is defined, U-Boot is linked against 715 the SLRE (Super Light Regular Expression) library, 716 which adds regex support to some commands, as for 717 example "env grep" and "setexpr". 718 719- Device tree: 720 CONFIG_OF_CONTROL 721 If this variable is defined, U-Boot will use a device tree 722 to configure its devices, instead of relying on statically 723 compiled #defines in the board file. This option is 724 experimental and only available on a few boards. The device 725 tree is available in the global data as gd->fdt_blob. 726 727 U-Boot needs to get its device tree from somewhere. This can 728 be done using one of the three options below: 729 730 CONFIG_OF_EMBED 731 If this variable is defined, U-Boot will embed a device tree 732 binary in its image. This device tree file should be in the 733 board directory and called <soc>-<board>.dts. The binary file 734 is then picked up in board_init_f() and made available through 735 the global data structure as gd->fdt_blob. 736 737 CONFIG_OF_SEPARATE 738 If this variable is defined, U-Boot will build a device tree 739 binary. It will be called u-boot.dtb. Architecture-specific 740 code will locate it at run-time. Generally this works by: 741 742 cat u-boot.bin u-boot.dtb >image.bin 743 744 and in fact, U-Boot does this for you, creating a file called 745 u-boot-dtb.bin which is useful in the common case. You can 746 still use the individual files if you need something more 747 exotic. 748 749 CONFIG_OF_BOARD 750 If this variable is defined, U-Boot will use the device tree 751 provided by the board at runtime instead of embedding one with 752 the image. Only boards defining board_fdt_blob_setup() support 753 this option (see include/fdtdec.h file). 754 755- Watchdog: 756 CONFIG_WATCHDOG 757 If this variable is defined, it enables watchdog 758 support for the SoC. There must be support in the SoC 759 specific code for a watchdog. For the 8xx 760 CPUs, the SIU Watchdog feature is enabled in the SYPCR 761 register. When supported for a specific SoC is 762 available, then no further board specific code should 763 be needed to use it. 764 765 CONFIG_HW_WATCHDOG 766 When using a watchdog circuitry external to the used 767 SoC, then define this variable and provide board 768 specific code for the "hw_watchdog_reset" function. 769 770 CONFIG_AT91_HW_WDT_TIMEOUT 771 specify the timeout in seconds. default 2 seconds. 772 773- Real-Time Clock: 774 775 When CONFIG_CMD_DATE is selected, the type of the RTC 776 has to be selected, too. Define exactly one of the 777 following options: 778 779 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 780 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC 781 CONFIG_RTC_MC146818 - use MC146818 RTC 782 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 783 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 784 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 785 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC 786 CONFIG_RTC_DS164x - use Dallas DS164x RTC 787 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC 788 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 789 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337 790 CONFIG_SYS_RV3029_TCR - enable trickle charger on 791 RV3029 RTC. 792 793 Note that if the RTC uses I2C, then the I2C interface 794 must also be configured. See I2C Support, below. 795 796- GPIO Support: 797 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO 798 799 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of 800 chip-ngpio pairs that tell the PCA953X driver the number of 801 pins supported by a particular chip. 802 803 Note that if the GPIO device uses I2C, then the I2C interface 804 must also be configured. See I2C Support, below. 805 806- I/O tracing: 807 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O 808 accesses and can checksum them or write a list of them out 809 to memory. See the 'iotrace' command for details. This is 810 useful for testing device drivers since it can confirm that 811 the driver behaves the same way before and after a code 812 change. Currently this is supported on sandbox and arm. To 813 add support for your architecture, add '#include <iotrace.h>' 814 to the bottom of arch/<arch>/include/asm/io.h and test. 815 816 Example output from the 'iotrace stats' command is below. 817 Note that if the trace buffer is exhausted, the checksum will 818 still continue to operate. 819 820 iotrace is enabled 821 Start: 10000000 (buffer start address) 822 Size: 00010000 (buffer size) 823 Offset: 00000120 (current buffer offset) 824 Output: 10000120 (start + offset) 825 Count: 00000018 (number of trace records) 826 CRC32: 9526fb66 (CRC32 of all trace records) 827 828- Timestamp Support: 829 830 When CONFIG_TIMESTAMP is selected, the timestamp 831 (date and time) of an image is printed by image 832 commands like bootm or iminfo. This option is 833 automatically enabled when you select CONFIG_CMD_DATE . 834 835- Partition Labels (disklabels) Supported: 836 Zero or more of the following: 837 CONFIG_MAC_PARTITION Apple's MacOS partition table. 838 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc. 839 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the 840 bootloader. Note 2TB partition limit; see 841 disk/part_efi.c 842 CONFIG_SCSI) you must configure support for at 843 least one non-MTD partition type as well. 844 845- IDE Reset method: 846 CONFIG_IDE_RESET_ROUTINE - this is defined in several 847 board configurations files but used nowhere! 848 849 CONFIG_IDE_RESET - is this is defined, IDE Reset will 850 be performed by calling the function 851 ide_set_reset(int reset) 852 which has to be defined in a board specific file 853 854- ATAPI Support: 855 CONFIG_ATAPI 856 857 Set this to enable ATAPI support. 858 859- LBA48 Support 860 CONFIG_LBA48 861 862 Set this to enable support for disks larger than 137GB 863 Also look at CONFIG_SYS_64BIT_LBA. 864 Whithout these , LBA48 support uses 32bit variables and will 'only' 865 support disks up to 2.1TB. 866 867 CONFIG_SYS_64BIT_LBA: 868 When enabled, makes the IDE subsystem use 64bit sector addresses. 869 Default is 32bit. 870 871- SCSI Support: 872 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and 873 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID * 874 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the 875 maximum numbers of LUNs, SCSI ID's and target 876 devices. 877 878 The environment variable 'scsidevs' is set to the number of 879 SCSI devices found during the last scan. 880 881- NETWORK Support (PCI): 882 CONFIG_E1000 883 Support for Intel 8254x/8257x gigabit chips. 884 885 CONFIG_E1000_SPI 886 Utility code for direct access to the SPI bus on Intel 8257x. 887 This does not do anything useful unless you set at least one 888 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC. 889 890 CONFIG_E1000_SPI_GENERIC 891 Allow generic access to the SPI bus on the Intel 8257x, for 892 example with the "sspi" command. 893 894 CONFIG_EEPRO100 895 Support for Intel 82557/82559/82559ER chips. 896 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM 897 write routine for first time initialisation. 898 899 CONFIG_TULIP 900 Support for Digital 2114x chips. 901 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 902 modem chip initialisation (KS8761/QS6611). 903 904 CONFIG_NATSEMI 905 Support for National dp83815 chips. 906 907 CONFIG_NS8382X 908 Support for National dp8382[01] gigabit chips. 909 910- NETWORK Support (other): 911 912 CONFIG_DRIVER_AT91EMAC 913 Support for AT91RM9200 EMAC. 914 915 CONFIG_RMII 916 Define this to use reduced MII inteface 917 918 CONFIG_DRIVER_AT91EMAC_QUIET 919 If this defined, the driver is quiet. 920 The driver doen't show link status messages. 921 922 CONFIG_CALXEDA_XGMAC 923 Support for the Calxeda XGMAC device 924 925 CONFIG_LAN91C96 926 Support for SMSC's LAN91C96 chips. 927 928 CONFIG_LAN91C96_USE_32_BIT 929 Define this to enable 32 bit addressing 930 931 CONFIG_SMC91111 932 Support for SMSC's LAN91C111 chip 933 934 CONFIG_SMC91111_BASE 935 Define this to hold the physical address 936 of the device (I/O space) 937 938 CONFIG_SMC_USE_32_BIT 939 Define this if data bus is 32 bits 940 941 CONFIG_SMC_USE_IOFUNCS 942 Define this to use i/o functions instead of macros 943 (some hardware wont work with macros) 944 945 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 946 Define this if you have more then 3 PHYs. 947 948 CONFIG_FTGMAC100 949 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 950 951 CONFIG_FTGMAC100_EGIGA 952 Define this to use GE link update with gigabit PHY. 953 Define this if FTGMAC100 is connected to gigabit PHY. 954 If your system has 10/100 PHY only, it might not occur 955 wrong behavior. Because PHY usually return timeout or 956 useless data when polling gigabit status and gigabit 957 control registers. This behavior won't affect the 958 correctnessof 10/100 link speed update. 959 960 CONFIG_SH_ETHER 961 Support for Renesas on-chip Ethernet controller 962 963 CONFIG_SH_ETHER_USE_PORT 964 Define the number of ports to be used 965 966 CONFIG_SH_ETHER_PHY_ADDR 967 Define the ETH PHY's address 968 969 CONFIG_SH_ETHER_CACHE_WRITEBACK 970 If this option is set, the driver enables cache flush. 971 972- PWM Support: 973 CONFIG_PWM_IMX 974 Support for PWM module on the imx6. 975 976- TPM Support: 977 CONFIG_TPM 978 Support TPM devices. 979 980 CONFIG_TPM_TIS_INFINEON 981 Support for Infineon i2c bus TPM devices. Only one device 982 per system is supported at this time. 983 984 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 985 Define the burst count bytes upper limit 986 987 CONFIG_TPM_ST33ZP24 988 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 989 990 CONFIG_TPM_ST33ZP24_I2C 991 Support for STMicroelectronics ST33ZP24 I2C devices. 992 Requires TPM_ST33ZP24 and I2C. 993 994 CONFIG_TPM_ST33ZP24_SPI 995 Support for STMicroelectronics ST33ZP24 SPI devices. 996 Requires TPM_ST33ZP24 and SPI. 997 998 CONFIG_TPM_ATMEL_TWI 999 Support for Atmel TWI TPM device. Requires I2C support. 1000 1001 CONFIG_TPM_TIS_LPC 1002 Support for generic parallel port TPM devices. Only one device 1003 per system is supported at this time. 1004 1005 CONFIG_TPM_TIS_BASE_ADDRESS 1006 Base address where the generic TPM device is mapped 1007 to. Contemporary x86 systems usually map it at 1008 0xfed40000. 1009 1010 CONFIG_TPM 1011 Define this to enable the TPM support library which provides 1012 functional interfaces to some TPM commands. 1013 Requires support for a TPM device. 1014 1015 CONFIG_TPM_AUTH_SESSIONS 1016 Define this to enable authorized functions in the TPM library. 1017 Requires CONFIG_TPM and CONFIG_SHA1. 1018 1019- USB Support: 1020 At the moment only the UHCI host controller is 1021 supported (PIP405, MIP405); define 1022 CONFIG_USB_UHCI to enable it. 1023 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 1024 and define CONFIG_USB_STORAGE to enable the USB 1025 storage devices. 1026 Note: 1027 Supported are USB Keyboards and USB Floppy drives 1028 (TEAC FD-05PUB). 1029 1030 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 1031 txfilltuning field in the EHCI controller on reset. 1032 1033 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2 1034 HW module registers. 1035 1036- USB Device: 1037 Define the below if you wish to use the USB console. 1038 Once firmware is rebuilt from a serial console issue the 1039 command "setenv stdin usbtty; setenv stdout usbtty" and 1040 attach your USB cable. The Unix command "dmesg" should print 1041 it has found a new device. The environment variable usbtty 1042 can be set to gserial or cdc_acm to enable your device to 1043 appear to a USB host as a Linux gserial device or a 1044 Common Device Class Abstract Control Model serial device. 1045 If you select usbtty = gserial you should be able to enumerate 1046 a Linux host by 1047 # modprobe usbserial vendor=0xVendorID product=0xProductID 1048 else if using cdc_acm, simply setting the environment 1049 variable usbtty to be cdc_acm should suffice. The following 1050 might be defined in YourBoardName.h 1051 1052 CONFIG_USB_DEVICE 1053 Define this to build a UDC device 1054 1055 CONFIG_USB_TTY 1056 Define this to have a tty type of device available to 1057 talk to the UDC device 1058 1059 CONFIG_USBD_HS 1060 Define this to enable the high speed support for usb 1061 device and usbtty. If this feature is enabled, a routine 1062 int is_usbd_high_speed(void) 1063 also needs to be defined by the driver to dynamically poll 1064 whether the enumeration has succeded at high speed or full 1065 speed. 1066 1067 CONFIG_SYS_CONSOLE_IS_IN_ENV 1068 Define this if you want stdin, stdout &/or stderr to 1069 be set to usbtty. 1070 1071 If you have a USB-IF assigned VendorID then you may wish to 1072 define your own vendor specific values either in BoardName.h 1073 or directly in usbd_vendor_info.h. If you don't define 1074 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 1075 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 1076 should pretend to be a Linux device to it's target host. 1077 1078 CONFIG_USBD_MANUFACTURER 1079 Define this string as the name of your company for 1080 - CONFIG_USBD_MANUFACTURER "my company" 1081 1082 CONFIG_USBD_PRODUCT_NAME 1083 Define this string as the name of your product 1084 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 1085 1086 CONFIG_USBD_VENDORID 1087 Define this as your assigned Vendor ID from the USB 1088 Implementors Forum. This *must* be a genuine Vendor ID 1089 to avoid polluting the USB namespace. 1090 - CONFIG_USBD_VENDORID 0xFFFF 1091 1092 CONFIG_USBD_PRODUCTID 1093 Define this as the unique Product ID 1094 for your device 1095 - CONFIG_USBD_PRODUCTID 0xFFFF 1096 1097- ULPI Layer Support: 1098 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 1099 the generic ULPI layer. The generic layer accesses the ULPI PHY 1100 via the platform viewport, so you need both the genric layer and 1101 the viewport enabled. Currently only Chipidea/ARC based 1102 viewport is supported. 1103 To enable the ULPI layer support, define CONFIG_USB_ULPI and 1104 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 1105 If your ULPI phy needs a different reference clock than the 1106 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 1107 the appropriate value in Hz. 1108 1109- MMC Support: 1110 The MMC controller on the Intel PXA is supported. To 1111 enable this define CONFIG_MMC. The MMC can be 1112 accessed from the boot prompt by mapping the device 1113 to physical memory similar to flash. Command line is 1114 enabled with CONFIG_CMD_MMC. The MMC driver also works with 1115 the FAT fs. This is enabled with CONFIG_CMD_FAT. 1116 1117 CONFIG_SH_MMCIF 1118 Support for Renesas on-chip MMCIF controller 1119 1120 CONFIG_SH_MMCIF_ADDR 1121 Define the base address of MMCIF registers 1122 1123 CONFIG_SH_MMCIF_CLK 1124 Define the clock frequency for MMCIF 1125 1126 CONFIG_SUPPORT_EMMC_BOOT 1127 Enable some additional features of the eMMC boot partitions. 1128 1129- USB Device Firmware Update (DFU) class support: 1130 CONFIG_DFU_OVER_USB 1131 This enables the USB portion of the DFU USB class 1132 1133 CONFIG_DFU_NAND 1134 This enables support for exposing NAND devices via DFU. 1135 1136 CONFIG_DFU_RAM 1137 This enables support for exposing RAM via DFU. 1138 Note: DFU spec refer to non-volatile memory usage, but 1139 allow usages beyond the scope of spec - here RAM usage, 1140 one that would help mostly the developer. 1141 1142 CONFIG_SYS_DFU_DATA_BUF_SIZE 1143 Dfu transfer uses a buffer before writing data to the 1144 raw storage device. Make the size (in bytes) of this buffer 1145 configurable. The size of this buffer is also configurable 1146 through the "dfu_bufsiz" environment variable. 1147 1148 CONFIG_SYS_DFU_MAX_FILE_SIZE 1149 When updating files rather than the raw storage device, 1150 we use a static buffer to copy the file into and then write 1151 the buffer once we've been given the whole file. Define 1152 this to the maximum filesize (in bytes) for the buffer. 1153 Default is 4 MiB if undefined. 1154 1155 DFU_DEFAULT_POLL_TIMEOUT 1156 Poll timeout [ms], is the timeout a device can send to the 1157 host. The host must wait for this timeout before sending 1158 a subsequent DFU_GET_STATUS request to the device. 1159 1160 DFU_MANIFEST_POLL_TIMEOUT 1161 Poll timeout [ms], which the device sends to the host when 1162 entering dfuMANIFEST state. Host waits this timeout, before 1163 sending again an USB request to the device. 1164 1165- Journaling Flash filesystem support: 1166 CONFIG_JFFS2_NAND 1167 Define these for a default partition on a NAND device 1168 1169 CONFIG_SYS_JFFS2_FIRST_SECTOR, 1170 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 1171 Define these for a default partition on a NOR device 1172 1173- Keyboard Support: 1174 See Kconfig help for available keyboard drivers. 1175 1176 CONFIG_KEYBOARD 1177 1178 Define this to enable a custom keyboard support. 1179 This simply calls drv_keyboard_init() which must be 1180 defined in your board-specific files. This option is deprecated 1181 and is only used by novena. For new boards, use driver model 1182 instead. 1183 1184- Video support: 1185 CONFIG_FSL_DIU_FB 1186 Enable the Freescale DIU video driver. Reference boards for 1187 SOCs that have a DIU should define this macro to enable DIU 1188 support, and should also define these other macros: 1189 1190 CONFIG_SYS_DIU_ADDR 1191 CONFIG_VIDEO 1192 CONFIG_CFB_CONSOLE 1193 CONFIG_VIDEO_SW_CURSOR 1194 CONFIG_VGA_AS_SINGLE_DEVICE 1195 CONFIG_VIDEO_LOGO 1196 CONFIG_VIDEO_BMP_LOGO 1197 1198 The DIU driver will look for the 'video-mode' environment 1199 variable, and if defined, enable the DIU as a console during 1200 boot. See the documentation file doc/README.video for a 1201 description of this variable. 1202 1203- LCD Support: CONFIG_LCD 1204 1205 Define this to enable LCD support (for output to LCD 1206 display); also select one of the supported displays 1207 by defining one of these: 1208 1209 CONFIG_ATMEL_LCD: 1210 1211 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1212 1213 CONFIG_NEC_NL6448AC33: 1214 1215 NEC NL6448AC33-18. Active, color, single scan. 1216 1217 CONFIG_NEC_NL6448BC20 1218 1219 NEC NL6448BC20-08. 6.5", 640x480. 1220 Active, color, single scan. 1221 1222 CONFIG_NEC_NL6448BC33_54 1223 1224 NEC NL6448BC33-54. 10.4", 640x480. 1225 Active, color, single scan. 1226 1227 CONFIG_SHARP_16x9 1228 1229 Sharp 320x240. Active, color, single scan. 1230 It isn't 16x9, and I am not sure what it is. 1231 1232 CONFIG_SHARP_LQ64D341 1233 1234 Sharp LQ64D341 display, 640x480. 1235 Active, color, single scan. 1236 1237 CONFIG_HLD1045 1238 1239 HLD1045 display, 640x480. 1240 Active, color, single scan. 1241 1242 CONFIG_OPTREX_BW 1243 1244 Optrex CBL50840-2 NF-FW 99 22 M5 1245 or 1246 Hitachi LMG6912RPFC-00T 1247 or 1248 Hitachi SP14Q002 1249 1250 320x240. Black & white. 1251 1252 CONFIG_LCD_ALIGNMENT 1253 1254 Normally the LCD is page-aligned (typically 4KB). If this is 1255 defined then the LCD will be aligned to this value instead. 1256 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1257 here, since it is cheaper to change data cache settings on 1258 a per-section basis. 1259 1260 1261 CONFIG_LCD_ROTATION 1262 1263 Sometimes, for example if the display is mounted in portrait 1264 mode or even if it's mounted landscape but rotated by 180degree, 1265 we need to rotate our content of the display relative to the 1266 framebuffer, so that user can read the messages which are 1267 printed out. 1268 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1269 initialized with a given rotation from "vl_rot" out of 1270 "vidinfo_t" which is provided by the board specific code. 1271 The value for vl_rot is coded as following (matching to 1272 fbcon=rotate:<n> linux-kernel commandline): 1273 0 = no rotation respectively 0 degree 1274 1 = 90 degree rotation 1275 2 = 180 degree rotation 1276 3 = 270 degree rotation 1277 1278 If CONFIG_LCD_ROTATION is not defined, the console will be 1279 initialized with 0degree rotation. 1280 1281 CONFIG_LCD_BMP_RLE8 1282 1283 Support drawing of RLE8-compressed bitmaps on the LCD. 1284 1285 CONFIG_I2C_EDID 1286 1287 Enables an 'i2c edid' command which can read EDID 1288 information over I2C from an attached LCD display. 1289 1290- Splash Screen Support: CONFIG_SPLASH_SCREEN 1291 1292 If this option is set, the environment is checked for 1293 a variable "splashimage". If found, the usual display 1294 of logo, copyright and system information on the LCD 1295 is suppressed and the BMP image at the address 1296 specified in "splashimage" is loaded instead. The 1297 console is redirected to the "nulldev", too. This 1298 allows for a "silent" boot where a splash screen is 1299 loaded very quickly after power-on. 1300 1301 CONFIG_SPLASHIMAGE_GUARD 1302 1303 If this option is set, then U-Boot will prevent the environment 1304 variable "splashimage" from being set to a problematic address 1305 (see doc/README.displaying-bmps). 1306 This option is useful for targets where, due to alignment 1307 restrictions, an improperly aligned BMP image will cause a data 1308 abort. If you think you will not have problems with unaligned 1309 accesses (for example because your toolchain prevents them) 1310 there is no need to set this option. 1311 1312 CONFIG_SPLASH_SCREEN_ALIGN 1313 1314 If this option is set the splash image can be freely positioned 1315 on the screen. Environment variable "splashpos" specifies the 1316 position as "x,y". If a positive number is given it is used as 1317 number of pixel from left/top. If a negative number is given it 1318 is used as number of pixel from right/bottom. You can also 1319 specify 'm' for centering the image. 1320 1321 Example: 1322 setenv splashpos m,m 1323 => image at center of screen 1324 1325 setenv splashpos 30,20 1326 => image at x = 30 and y = 20 1327 1328 setenv splashpos -10,m 1329 => vertically centered image 1330 at x = dspWidth - bmpWidth - 9 1331 1332- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP 1333 1334 If this option is set, additionally to standard BMP 1335 images, gzipped BMP images can be displayed via the 1336 splashscreen support or the bmp command. 1337 1338- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8 1339 1340 If this option is set, 8-bit RLE compressed BMP images 1341 can be displayed via the splashscreen support or the 1342 bmp command. 1343 1344- Compression support: 1345 CONFIG_GZIP 1346 1347 Enabled by default to support gzip compressed images. 1348 1349 CONFIG_BZIP2 1350 1351 If this option is set, support for bzip2 compressed 1352 images is included. If not, only uncompressed and gzip 1353 compressed images are supported. 1354 1355 NOTE: the bzip2 algorithm requires a lot of RAM, so 1356 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should 1357 be at least 4MB. 1358 1359- MII/PHY support: 1360 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1361 1362 The clock frequency of the MII bus 1363 1364 CONFIG_PHY_RESET_DELAY 1365 1366 Some PHY like Intel LXT971A need extra delay after 1367 reset before any MII register access is possible. 1368 For such PHY, set this option to the usec delay 1369 required. (minimum 300usec for LXT971A) 1370 1371 CONFIG_PHY_CMD_DELAY (ppc4xx) 1372 1373 Some PHY like Intel LXT971A need extra delay after 1374 command issued before MII status register can be read 1375 1376- IP address: 1377 CONFIG_IPADDR 1378 1379 Define a default value for the IP address to use for 1380 the default Ethernet interface, in case this is not 1381 determined through e.g. bootp. 1382 (Environment variable "ipaddr") 1383 1384- Server IP address: 1385 CONFIG_SERVERIP 1386 1387 Defines a default value for the IP address of a TFTP 1388 server to contact when using the "tftboot" command. 1389 (Environment variable "serverip") 1390 1391 CONFIG_KEEP_SERVERADDR 1392 1393 Keeps the server's MAC address, in the env 'serveraddr' 1394 for passing to bootargs (like Linux's netconsole option) 1395 1396- Gateway IP address: 1397 CONFIG_GATEWAYIP 1398 1399 Defines a default value for the IP address of the 1400 default router where packets to other networks are 1401 sent to. 1402 (Environment variable "gatewayip") 1403 1404- Subnet mask: 1405 CONFIG_NETMASK 1406 1407 Defines a default value for the subnet mask (or 1408 routing prefix) which is used to determine if an IP 1409 address belongs to the local subnet or needs to be 1410 forwarded through a router. 1411 (Environment variable "netmask") 1412 1413- BOOTP Recovery Mode: 1414 CONFIG_BOOTP_RANDOM_DELAY 1415 1416 If you have many targets in a network that try to 1417 boot using BOOTP, you may want to avoid that all 1418 systems send out BOOTP requests at precisely the same 1419 moment (which would happen for instance at recovery 1420 from a power failure, when all systems will try to 1421 boot, thus flooding the BOOTP server. Defining 1422 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1423 inserted before sending out BOOTP requests. The 1424 following delays are inserted then: 1425 1426 1st BOOTP request: delay 0 ... 1 sec 1427 2nd BOOTP request: delay 0 ... 2 sec 1428 3rd BOOTP request: delay 0 ... 4 sec 1429 4th and following 1430 BOOTP requests: delay 0 ... 8 sec 1431 1432 CONFIG_BOOTP_ID_CACHE_SIZE 1433 1434 BOOTP packets are uniquely identified using a 32-bit ID. The 1435 server will copy the ID from client requests to responses and 1436 U-Boot will use this to determine if it is the destination of 1437 an incoming response. Some servers will check that addresses 1438 aren't in use before handing them out (usually using an ARP 1439 ping) and therefore take up to a few hundred milliseconds to 1440 respond. Network congestion may also influence the time it 1441 takes for a response to make it back to the client. If that 1442 time is too long, U-Boot will retransmit requests. In order 1443 to allow earlier responses to still be accepted after these 1444 retransmissions, U-Boot's BOOTP client keeps a small cache of 1445 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1446 cache. The default is to keep IDs for up to four outstanding 1447 requests. Increasing this will allow U-Boot to accept offers 1448 from a BOOTP client in networks with unusually high latency. 1449 1450- DHCP Advanced Options: 1451 You can fine tune the DHCP functionality by defining 1452 CONFIG_BOOTP_* symbols: 1453 1454 CONFIG_BOOTP_NISDOMAIN 1455 CONFIG_BOOTP_BOOTFILESIZE 1456 CONFIG_BOOTP_SEND_HOSTNAME 1457 CONFIG_BOOTP_NTPSERVER 1458 CONFIG_BOOTP_TIMEOFFSET 1459 CONFIG_BOOTP_VENDOREX 1460 CONFIG_BOOTP_MAY_FAIL 1461 1462 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1463 environment variable, not the BOOTP server. 1464 1465 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1466 after the configured retry count, the call will fail 1467 instead of starting over. This can be used to fail over 1468 to Link-local IP address configuration if the DHCP server 1469 is not available. 1470 1471 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1472 to do a dynamic update of a DNS server. To do this, they 1473 need the hostname of the DHCP requester. 1474 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1475 of the "hostname" environment variable is passed as 1476 option 12 to the DHCP server. 1477 1478 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1479 1480 A 32bit value in microseconds for a delay between 1481 receiving a "DHCP Offer" and sending the "DHCP Request". 1482 This fixes a problem with certain DHCP servers that don't 1483 respond 100% of the time to a "DHCP request". E.g. On an 1484 AT91RM9200 processor running at 180MHz, this delay needed 1485 to be *at least* 15,000 usec before a Windows Server 2003 1486 DHCP server would reply 100% of the time. I recommend at 1487 least 50,000 usec to be safe. The alternative is to hope 1488 that one of the retries will be successful but note that 1489 the DHCP timeout and retry process takes a longer than 1490 this delay. 1491 1492 - Link-local IP address negotiation: 1493 Negotiate with other link-local clients on the local network 1494 for an address that doesn't require explicit configuration. 1495 This is especially useful if a DHCP server cannot be guaranteed 1496 to exist in all environments that the device must operate. 1497 1498 See doc/README.link-local for more information. 1499 1500 - MAC address from environment variables 1501 1502 FDT_SEQ_MACADDR_FROM_ENV 1503 1504 Fix-up device tree with MAC addresses fetched sequentially from 1505 environment variables. This config work on assumption that 1506 non-usable ethernet node of device-tree are either not present 1507 or their status has been marked as "disabled". 1508 1509 - CDP Options: 1510 CONFIG_CDP_DEVICE_ID 1511 1512 The device id used in CDP trigger frames. 1513 1514 CONFIG_CDP_DEVICE_ID_PREFIX 1515 1516 A two character string which is prefixed to the MAC address 1517 of the device. 1518 1519 CONFIG_CDP_PORT_ID 1520 1521 A printf format string which contains the ascii name of 1522 the port. Normally is set to "eth%d" which sets 1523 eth0 for the first Ethernet, eth1 for the second etc. 1524 1525 CONFIG_CDP_CAPABILITIES 1526 1527 A 32bit integer which indicates the device capabilities; 1528 0x00000010 for a normal host which does not forwards. 1529 1530 CONFIG_CDP_VERSION 1531 1532 An ascii string containing the version of the software. 1533 1534 CONFIG_CDP_PLATFORM 1535 1536 An ascii string containing the name of the platform. 1537 1538 CONFIG_CDP_TRIGGER 1539 1540 A 32bit integer sent on the trigger. 1541 1542 CONFIG_CDP_POWER_CONSUMPTION 1543 1544 A 16bit integer containing the power consumption of the 1545 device in .1 of milliwatts. 1546 1547 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1548 1549 A byte containing the id of the VLAN. 1550 1551- Status LED: CONFIG_LED_STATUS 1552 1553 Several configurations allow to display the current 1554 status using a LED. For instance, the LED will blink 1555 fast while running U-Boot code, stop blinking as 1556 soon as a reply to a BOOTP request was received, and 1557 start blinking slow once the Linux kernel is running 1558 (supported by a status LED driver in the Linux 1559 kernel). Defining CONFIG_LED_STATUS enables this 1560 feature in U-Boot. 1561 1562 Additional options: 1563 1564 CONFIG_LED_STATUS_GPIO 1565 The status LED can be connected to a GPIO pin. 1566 In such cases, the gpio_led driver can be used as a 1567 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1568 to include the gpio_led driver in the U-Boot binary. 1569 1570 CONFIG_GPIO_LED_INVERTED_TABLE 1571 Some GPIO connected LEDs may have inverted polarity in which 1572 case the GPIO high value corresponds to LED off state and 1573 GPIO low value corresponds to LED on state. 1574 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1575 with a list of GPIO LEDs that have inverted polarity. 1576 1577- I2C Support: CONFIG_SYS_I2C 1578 1579 This enable the NEW i2c subsystem, and will allow you to use 1580 i2c commands at the u-boot command line (as long as you set 1581 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c 1582 based realtime clock chips or other i2c devices. See 1583 common/cmd_i2c.c for a description of the command line 1584 interface. 1585 1586 ported i2c driver to the new framework: 1587 - drivers/i2c/soft_i2c.c: 1588 - activate first bus with CONFIG_SYS_I2C_SOFT define 1589 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1590 for defining speed and slave address 1591 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1592 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1593 for defining speed and slave address 1594 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1595 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1596 for defining speed and slave address 1597 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1598 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1599 for defining speed and slave address 1600 1601 - drivers/i2c/fsl_i2c.c: 1602 - activate i2c driver with CONFIG_SYS_I2C_FSL 1603 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1604 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1605 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1606 bus. 1607 - If your board supports a second fsl i2c bus, define 1608 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1609 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1610 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1611 second bus. 1612 1613 - drivers/i2c/tegra_i2c.c: 1614 - activate this driver with CONFIG_SYS_I2C_TEGRA 1615 - This driver adds 4 i2c buses with a fix speed from 1616 100000 and the slave addr 0! 1617 1618 - drivers/i2c/ppc4xx_i2c.c 1619 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1620 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1621 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1622 1623 - drivers/i2c/i2c_mxc.c 1624 - activate this driver with CONFIG_SYS_I2C_MXC 1625 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1626 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1627 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1628 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1629 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1630 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1631 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1632 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1633 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1634 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1635 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1636 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1637 If those defines are not set, default value is 100000 1638 for speed, and 0 for slave. 1639 1640 - drivers/i2c/rcar_i2c.c: 1641 - activate this driver with CONFIG_SYS_I2C_RCAR 1642 - This driver adds 4 i2c buses 1643 1644 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 1645 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 1646 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 1647 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 1648 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 1649 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 1650 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 1651 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 1652 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses 1653 1654 - drivers/i2c/sh_i2c.c: 1655 - activate this driver with CONFIG_SYS_I2C_SH 1656 - This driver adds from 2 to 5 i2c buses 1657 1658 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1659 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1660 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1661 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1662 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1663 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1664 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1665 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1666 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1667 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1668 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1669 1670 - drivers/i2c/omap24xx_i2c.c 1671 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1672 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1673 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1674 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1675 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1676 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1677 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1678 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1679 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1680 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1681 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1682 1683 - drivers/i2c/s3c24x0_i2c.c: 1684 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1685 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1686 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1687 with a fix speed from 100000 and the slave addr 0! 1688 1689 - drivers/i2c/ihs_i2c.c 1690 - activate this driver with CONFIG_SYS_I2C_IHS 1691 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1692 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1693 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1694 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1695 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1696 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1697 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1698 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1699 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1700 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1701 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1702 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1703 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1704 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1705 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1706 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1707 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1708 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1709 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1710 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1711 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1712 1713 additional defines: 1714 1715 CONFIG_SYS_NUM_I2C_BUSES 1716 Hold the number of i2c buses you want to use. 1717 1718 CONFIG_SYS_I2C_DIRECT_BUS 1719 define this, if you don't use i2c muxes on your hardware. 1720 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1721 omit this define. 1722 1723 CONFIG_SYS_I2C_MAX_HOPS 1724 define how many muxes are maximal consecutively connected 1725 on one i2c bus. If you not use i2c muxes, omit this 1726 define. 1727 1728 CONFIG_SYS_I2C_BUSES 1729 hold a list of buses you want to use, only used if 1730 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1731 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1732 CONFIG_SYS_NUM_I2C_BUSES = 9: 1733 1734 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1735 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1736 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1737 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1738 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1739 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1740 {1, {I2C_NULL_HOP}}, \ 1741 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1742 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1743 } 1744 1745 which defines 1746 bus 0 on adapter 0 without a mux 1747 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1748 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1749 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1750 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1751 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1752 bus 6 on adapter 1 without a mux 1753 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1754 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1755 1756 If you do not have i2c muxes on your board, omit this define. 1757 1758- Legacy I2C Support: 1759 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1760 then the following macros need to be defined (examples are 1761 from include/configs/lwmon.h): 1762 1763 I2C_INIT 1764 1765 (Optional). Any commands necessary to enable the I2C 1766 controller or configure ports. 1767 1768 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1769 1770 I2C_ACTIVE 1771 1772 The code necessary to make the I2C data line active 1773 (driven). If the data line is open collector, this 1774 define can be null. 1775 1776 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1777 1778 I2C_TRISTATE 1779 1780 The code necessary to make the I2C data line tri-stated 1781 (inactive). If the data line is open collector, this 1782 define can be null. 1783 1784 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1785 1786 I2C_READ 1787 1788 Code that returns true if the I2C data line is high, 1789 false if it is low. 1790 1791 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1792 1793 I2C_SDA(bit) 1794 1795 If <bit> is true, sets the I2C data line high. If it 1796 is false, it clears it (low). 1797 1798 eg: #define I2C_SDA(bit) \ 1799 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1800 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1801 1802 I2C_SCL(bit) 1803 1804 If <bit> is true, sets the I2C clock line high. If it 1805 is false, it clears it (low). 1806 1807 eg: #define I2C_SCL(bit) \ 1808 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1809 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1810 1811 I2C_DELAY 1812 1813 This delay is invoked four times per clock cycle so this 1814 controls the rate of data transfer. The data rate thus 1815 is 1 / (I2C_DELAY * 4). Often defined to be something 1816 like: 1817 1818 #define I2C_DELAY udelay(2) 1819 1820 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1821 1822 If your arch supports the generic GPIO framework (asm/gpio.h), 1823 then you may alternatively define the two GPIOs that are to be 1824 used as SCL / SDA. Any of the previous I2C_xxx macros will 1825 have GPIO-based defaults assigned to them as appropriate. 1826 1827 You should define these to the GPIO value as given directly to 1828 the generic GPIO functions. 1829 1830 CONFIG_SYS_I2C_INIT_BOARD 1831 1832 When a board is reset during an i2c bus transfer 1833 chips might think that the current transfer is still 1834 in progress. On some boards it is possible to access 1835 the i2c SCLK line directly, either by using the 1836 processor pin as a GPIO or by having a second pin 1837 connected to the bus. If this option is defined a 1838 custom i2c_init_board() routine in boards/xxx/board.c 1839 is run early in the boot sequence. 1840 1841 CONFIG_I2C_MULTI_BUS 1842 1843 This option allows the use of multiple I2C buses, each of which 1844 must have a controller. At any point in time, only one bus is 1845 active. To switch to a different bus, use the 'i2c dev' command. 1846 Note that bus numbering is zero-based. 1847 1848 CONFIG_SYS_I2C_NOPROBES 1849 1850 This option specifies a list of I2C devices that will be skipped 1851 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1852 is set, specify a list of bus-device pairs. Otherwise, specify 1853 a 1D array of device addresses 1854 1855 e.g. 1856 #undef CONFIG_I2C_MULTI_BUS 1857 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1858 1859 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1860 1861 #define CONFIG_I2C_MULTI_BUS 1862 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1863 1864 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1865 1866 CONFIG_SYS_SPD_BUS_NUM 1867 1868 If defined, then this indicates the I2C bus number for DDR SPD. 1869 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1870 1871 CONFIG_SYS_RTC_BUS_NUM 1872 1873 If defined, then this indicates the I2C bus number for the RTC. 1874 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1875 1876 CONFIG_SOFT_I2C_READ_REPEATED_START 1877 1878 defining this will force the i2c_read() function in 1879 the soft_i2c driver to perform an I2C repeated start 1880 between writing the address pointer and reading the 1881 data. If this define is omitted the default behaviour 1882 of doing a stop-start sequence will be used. Most I2C 1883 devices can use either method, but some require one or 1884 the other. 1885 1886- SPI Support: CONFIG_SPI 1887 1888 Enables SPI driver (so far only tested with 1889 SPI EEPROM, also an instance works with Crystal A/D and 1890 D/As on the SACSng board) 1891 1892 CONFIG_SOFT_SPI 1893 1894 Enables a software (bit-bang) SPI driver rather than 1895 using hardware support. This is a general purpose 1896 driver that only requires three general I/O port pins 1897 (two outputs, one input) to function. If this is 1898 defined, the board configuration must define several 1899 SPI configuration items (port pins to use, etc). For 1900 an example, see include/configs/sacsng.h. 1901 1902 CONFIG_SYS_SPI_MXC_WAIT 1903 Timeout for waiting until spi transfer completed. 1904 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1905 1906- FPGA Support: CONFIG_FPGA 1907 1908 Enables FPGA subsystem. 1909 1910 CONFIG_FPGA_<vendor> 1911 1912 Enables support for specific chip vendors. 1913 (ALTERA, XILINX) 1914 1915 CONFIG_FPGA_<family> 1916 1917 Enables support for FPGA family. 1918 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1919 1920 CONFIG_FPGA_COUNT 1921 1922 Specify the number of FPGA devices to support. 1923 1924 CONFIG_SYS_FPGA_PROG_FEEDBACK 1925 1926 Enable printing of hash marks during FPGA configuration. 1927 1928 CONFIG_SYS_FPGA_CHECK_BUSY 1929 1930 Enable checks on FPGA configuration interface busy 1931 status by the configuration function. This option 1932 will require a board or device specific function to 1933 be written. 1934 1935 CONFIG_FPGA_DELAY 1936 1937 If defined, a function that provides delays in the FPGA 1938 configuration driver. 1939 1940 CONFIG_SYS_FPGA_CHECK_CTRLC 1941 Allow Control-C to interrupt FPGA configuration 1942 1943 CONFIG_SYS_FPGA_CHECK_ERROR 1944 1945 Check for configuration errors during FPGA bitfile 1946 loading. For example, abort during Virtex II 1947 configuration if the INIT_B line goes low (which 1948 indicated a CRC error). 1949 1950 CONFIG_SYS_FPGA_WAIT_INIT 1951 1952 Maximum time to wait for the INIT_B line to de-assert 1953 after PROB_B has been de-asserted during a Virtex II 1954 FPGA configuration sequence. The default time is 500 1955 ms. 1956 1957 CONFIG_SYS_FPGA_WAIT_BUSY 1958 1959 Maximum time to wait for BUSY to de-assert during 1960 Virtex II FPGA configuration. The default is 5 ms. 1961 1962 CONFIG_SYS_FPGA_WAIT_CONFIG 1963 1964 Time to wait after FPGA configuration. The default is 1965 200 ms. 1966 1967- Configuration Management: 1968 1969 CONFIG_IDENT_STRING 1970 1971 If defined, this string will be added to the U-Boot 1972 version information (U_BOOT_VERSION) 1973 1974- Vendor Parameter Protection: 1975 1976 U-Boot considers the values of the environment 1977 variables "serial#" (Board Serial Number) and 1978 "ethaddr" (Ethernet Address) to be parameters that 1979 are set once by the board vendor / manufacturer, and 1980 protects these variables from casual modification by 1981 the user. Once set, these variables are read-only, 1982 and write or delete attempts are rejected. You can 1983 change this behaviour: 1984 1985 If CONFIG_ENV_OVERWRITE is #defined in your config 1986 file, the write protection for vendor parameters is 1987 completely disabled. Anybody can change or delete 1988 these parameters. 1989 1990 Alternatively, if you define _both_ an ethaddr in the 1991 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1992 Ethernet address is installed in the environment, 1993 which can be changed exactly ONCE by the user. [The 1994 serial# is unaffected by this, i. e. it remains 1995 read-only.] 1996 1997 The same can be accomplished in a more flexible way 1998 for any variable by configuring the type of access 1999 to allow for those variables in the ".flags" variable 2000 or define CONFIG_ENV_FLAGS_LIST_STATIC. 2001 2002- Protected RAM: 2003 CONFIG_PRAM 2004 2005 Define this variable to enable the reservation of 2006 "protected RAM", i. e. RAM which is not overwritten 2007 by U-Boot. Define CONFIG_PRAM to hold the number of 2008 kB you want to reserve for pRAM. You can overwrite 2009 this default value by defining an environment 2010 variable "pram" to the number of kB you want to 2011 reserve. Note that the board info structure will 2012 still show the full amount of RAM. If pRAM is 2013 reserved, a new environment variable "mem" will 2014 automatically be defined to hold the amount of 2015 remaining RAM in a form that can be passed as boot 2016 argument to Linux, for instance like that: 2017 2018 setenv bootargs ... mem=\${mem} 2019 saveenv 2020 2021 This way you can tell Linux not to use this memory, 2022 either, which results in a memory region that will 2023 not be affected by reboots. 2024 2025 *WARNING* If your board configuration uses automatic 2026 detection of the RAM size, you must make sure that 2027 this memory test is non-destructive. So far, the 2028 following board configurations are known to be 2029 "pRAM-clean": 2030 2031 IVMS8, IVML24, SPD8xx, 2032 HERMES, IP860, RPXlite, LWMON, 2033 FLAGADM 2034 2035- Access to physical memory region (> 4GB) 2036 Some basic support is provided for operations on memory not 2037 normally accessible to U-Boot - e.g. some architectures 2038 support access to more than 4GB of memory on 32-bit 2039 machines using physical address extension or similar. 2040 Define CONFIG_PHYSMEM to access this basic support, which 2041 currently only supports clearing the memory. 2042 2043- Error Recovery: 2044 CONFIG_NET_RETRY_COUNT 2045 2046 This variable defines the number of retries for 2047 network operations like ARP, RARP, TFTP, or BOOTP 2048 before giving up the operation. If not defined, a 2049 default value of 5 is used. 2050 2051 CONFIG_ARP_TIMEOUT 2052 2053 Timeout waiting for an ARP reply in milliseconds. 2054 2055 CONFIG_NFS_TIMEOUT 2056 2057 Timeout in milliseconds used in NFS protocol. 2058 If you encounter "ERROR: Cannot umount" in nfs command, 2059 try longer timeout such as 2060 #define CONFIG_NFS_TIMEOUT 10000UL 2061 2062- Command Interpreter: 2063 CONFIG_SYS_PROMPT_HUSH_PS2 2064 2065 This defines the secondary prompt string, which is 2066 printed when the command interpreter needs more input 2067 to complete a command. Usually "> ". 2068 2069 Note: 2070 2071 In the current implementation, the local variables 2072 space and global environment variables space are 2073 separated. Local variables are those you define by 2074 simply typing `name=value'. To access a local 2075 variable later on, you have write `$name' or 2076 `${name}'; to execute the contents of a variable 2077 directly type `$name' at the command prompt. 2078 2079 Global environment variables are those you use 2080 setenv/printenv to work with. To run a command stored 2081 in such a variable, you need to use the run command, 2082 and you must not use the '$' sign to access them. 2083 2084 To store commands and special characters in a 2085 variable, please use double quotation marks 2086 surrounding the whole text of the variable, instead 2087 of the backslashes before semicolons and special 2088 symbols. 2089 2090- Command Line Editing and History: 2091 CONFIG_CMDLINE_PS_SUPPORT 2092 2093 Enable support for changing the command prompt string 2094 at run-time. Only static string is supported so far. 2095 The string is obtained from environment variables PS1 2096 and PS2. 2097 2098- Default Environment: 2099 CONFIG_EXTRA_ENV_SETTINGS 2100 2101 Define this to contain any number of null terminated 2102 strings (variable = value pairs) that will be part of 2103 the default environment compiled into the boot image. 2104 2105 For example, place something like this in your 2106 board's config file: 2107 2108 #define CONFIG_EXTRA_ENV_SETTINGS \ 2109 "myvar1=value1\0" \ 2110 "myvar2=value2\0" 2111 2112 Warning: This method is based on knowledge about the 2113 internal format how the environment is stored by the 2114 U-Boot code. This is NOT an official, exported 2115 interface! Although it is unlikely that this format 2116 will change soon, there is no guarantee either. 2117 You better know what you are doing here. 2118 2119 Note: overly (ab)use of the default environment is 2120 discouraged. Make sure to check other ways to preset 2121 the environment like the "source" command or the 2122 boot command first. 2123 2124 CONFIG_DELAY_ENVIRONMENT 2125 2126 Normally the environment is loaded when the board is 2127 initialised so that it is available to U-Boot. This inhibits 2128 that so that the environment is not available until 2129 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 2130 this is instead controlled by the value of 2131 /config/load-environment. 2132 2133- TFTP Fixed UDP Port: 2134 CONFIG_TFTP_PORT 2135 2136 If this is defined, the environment variable tftpsrcp 2137 is used to supply the TFTP UDP source port value. 2138 If tftpsrcp isn't defined, the normal pseudo-random port 2139 number generator is used. 2140 2141 Also, the environment variable tftpdstp is used to supply 2142 the TFTP UDP destination port value. If tftpdstp isn't 2143 defined, the normal port 69 is used. 2144 2145 The purpose for tftpsrcp is to allow a TFTP server to 2146 blindly start the TFTP transfer using the pre-configured 2147 target IP address and UDP port. This has the effect of 2148 "punching through" the (Windows XP) firewall, allowing 2149 the remainder of the TFTP transfer to proceed normally. 2150 A better solution is to properly configure the firewall, 2151 but sometimes that is not allowed. 2152 2153- Show boot progress: 2154 CONFIG_SHOW_BOOT_PROGRESS 2155 2156 Defining this option allows to add some board- 2157 specific code (calling a user-provided function 2158 "show_boot_progress(int)") that enables you to show 2159 the system's boot progress on some display (for 2160 example, some LED's) on your board. At the moment, 2161 the following checkpoints are implemented: 2162 2163 2164Legacy uImage format: 2165 2166 Arg Where When 2167 1 common/cmd_bootm.c before attempting to boot an image 2168 -1 common/cmd_bootm.c Image header has bad magic number 2169 2 common/cmd_bootm.c Image header has correct magic number 2170 -2 common/cmd_bootm.c Image header has bad checksum 2171 3 common/cmd_bootm.c Image header has correct checksum 2172 -3 common/cmd_bootm.c Image data has bad checksum 2173 4 common/cmd_bootm.c Image data has correct checksum 2174 -4 common/cmd_bootm.c Image is for unsupported architecture 2175 5 common/cmd_bootm.c Architecture check OK 2176 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi) 2177 6 common/cmd_bootm.c Image Type check OK 2178 -6 common/cmd_bootm.c gunzip uncompression error 2179 -7 common/cmd_bootm.c Unimplemented compression type 2180 7 common/cmd_bootm.c Uncompression OK 2181 8 common/cmd_bootm.c No uncompress/copy overwrite error 2182 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 2183 2184 9 common/image.c Start initial ramdisk verification 2185 -10 common/image.c Ramdisk header has bad magic number 2186 -11 common/image.c Ramdisk header has bad checksum 2187 10 common/image.c Ramdisk header is OK 2188 -12 common/image.c Ramdisk data has bad checksum 2189 11 common/image.c Ramdisk data has correct checksum 2190 12 common/image.c Ramdisk verification complete, start loading 2191 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk) 2192 13 common/image.c Start multifile image verification 2193 14 common/image.c No initial ramdisk, no multifile, continue. 2194 2195 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS 2196 2197 -30 arch/powerpc/lib/board.c Fatal error, hang the system 2198 -31 post/post.c POST test failed, detected by post_output_backlog() 2199 -32 post/post.c POST test failed, detected by post_run_single() 2200 2201 34 common/cmd_doc.c before loading a Image from a DOC device 2202 -35 common/cmd_doc.c Bad usage of "doc" command 2203 35 common/cmd_doc.c correct usage of "doc" command 2204 -36 common/cmd_doc.c No boot device 2205 36 common/cmd_doc.c correct boot device 2206 -37 common/cmd_doc.c Unknown Chip ID on boot device 2207 37 common/cmd_doc.c correct chip ID found, device available 2208 -38 common/cmd_doc.c Read Error on boot device 2209 38 common/cmd_doc.c reading Image header from DOC device OK 2210 -39 common/cmd_doc.c Image header has bad magic number 2211 39 common/cmd_doc.c Image header has correct magic number 2212 -40 common/cmd_doc.c Error reading Image from DOC device 2213 40 common/cmd_doc.c Image header has correct magic number 2214 41 common/cmd_ide.c before loading a Image from a IDE device 2215 -42 common/cmd_ide.c Bad usage of "ide" command 2216 42 common/cmd_ide.c correct usage of "ide" command 2217 -43 common/cmd_ide.c No boot device 2218 43 common/cmd_ide.c boot device found 2219 -44 common/cmd_ide.c Device not available 2220 44 common/cmd_ide.c Device available 2221 -45 common/cmd_ide.c wrong partition selected 2222 45 common/cmd_ide.c partition selected 2223 -46 common/cmd_ide.c Unknown partition table 2224 46 common/cmd_ide.c valid partition table found 2225 -47 common/cmd_ide.c Invalid partition type 2226 47 common/cmd_ide.c correct partition type 2227 -48 common/cmd_ide.c Error reading Image Header on boot device 2228 48 common/cmd_ide.c reading Image Header from IDE device OK 2229 -49 common/cmd_ide.c Image header has bad magic number 2230 49 common/cmd_ide.c Image header has correct magic number 2231 -50 common/cmd_ide.c Image header has bad checksum 2232 50 common/cmd_ide.c Image header has correct checksum 2233 -51 common/cmd_ide.c Error reading Image from IDE device 2234 51 common/cmd_ide.c reading Image from IDE device OK 2235 52 common/cmd_nand.c before loading a Image from a NAND device 2236 -53 common/cmd_nand.c Bad usage of "nand" command 2237 53 common/cmd_nand.c correct usage of "nand" command 2238 -54 common/cmd_nand.c No boot device 2239 54 common/cmd_nand.c boot device found 2240 -55 common/cmd_nand.c Unknown Chip ID on boot device 2241 55 common/cmd_nand.c correct chip ID found, device available 2242 -56 common/cmd_nand.c Error reading Image Header on boot device 2243 56 common/cmd_nand.c reading Image Header from NAND device OK 2244 -57 common/cmd_nand.c Image header has bad magic number 2245 57 common/cmd_nand.c Image header has correct magic number 2246 -58 common/cmd_nand.c Error reading Image from NAND device 2247 58 common/cmd_nand.c reading Image from NAND device OK 2248 2249 -60 common/env_common.c Environment has a bad CRC, using default 2250 2251 64 net/eth.c starting with Ethernet configuration. 2252 -64 net/eth.c no Ethernet found. 2253 65 net/eth.c Ethernet found. 2254 2255 -80 common/cmd_net.c usage wrong 2256 80 common/cmd_net.c before calling net_loop() 2257 -81 common/cmd_net.c some error in net_loop() occurred 2258 81 common/cmd_net.c net_loop() back without error 2259 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 2260 82 common/cmd_net.c trying automatic boot 2261 83 common/cmd_net.c running "source" command 2262 -83 common/cmd_net.c some error in automatic boot or "source" command 2263 84 common/cmd_net.c end without errors 2264 2265FIT uImage format: 2266 2267 Arg Where When 2268 100 common/cmd_bootm.c Kernel FIT Image has correct format 2269 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format 2270 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration 2271 -101 common/cmd_bootm.c Can't get configuration for kernel subimage 2272 102 common/cmd_bootm.c Kernel unit name specified 2273 -103 common/cmd_bootm.c Can't get kernel subimage node offset 2274 103 common/cmd_bootm.c Found configuration node 2275 104 common/cmd_bootm.c Got kernel subimage node offset 2276 -104 common/cmd_bootm.c Kernel subimage hash verification failed 2277 105 common/cmd_bootm.c Kernel subimage hash verification OK 2278 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture 2279 106 common/cmd_bootm.c Architecture check OK 2280 -106 common/cmd_bootm.c Kernel subimage has wrong type 2281 107 common/cmd_bootm.c Kernel subimage type OK 2282 -107 common/cmd_bootm.c Can't get kernel subimage data/size 2283 108 common/cmd_bootm.c Got kernel subimage data/size 2284 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT) 2285 -109 common/cmd_bootm.c Can't get kernel subimage type 2286 -110 common/cmd_bootm.c Can't get kernel subimage comp 2287 -111 common/cmd_bootm.c Can't get kernel subimage os 2288 -112 common/cmd_bootm.c Can't get kernel subimage load address 2289 -113 common/cmd_bootm.c Image uncompress/copy overwrite error 2290 2291 120 common/image.c Start initial ramdisk verification 2292 -120 common/image.c Ramdisk FIT image has incorrect format 2293 121 common/image.c Ramdisk FIT image has correct format 2294 122 common/image.c No ramdisk subimage unit name, using configuration 2295 -122 common/image.c Can't get configuration for ramdisk subimage 2296 123 common/image.c Ramdisk unit name specified 2297 -124 common/image.c Can't get ramdisk subimage node offset 2298 125 common/image.c Got ramdisk subimage node offset 2299 -125 common/image.c Ramdisk subimage hash verification failed 2300 126 common/image.c Ramdisk subimage hash verification OK 2301 -126 common/image.c Ramdisk subimage for unsupported architecture 2302 127 common/image.c Architecture check OK 2303 -127 common/image.c Can't get ramdisk subimage data/size 2304 128 common/image.c Got ramdisk subimage data/size 2305 129 common/image.c Can't get ramdisk load address 2306 -129 common/image.c Got ramdisk load address 2307 2308 -130 common/cmd_doc.c Incorrect FIT image format 2309 131 common/cmd_doc.c FIT image format OK 2310 2311 -140 common/cmd_ide.c Incorrect FIT image format 2312 141 common/cmd_ide.c FIT image format OK 2313 2314 -150 common/cmd_nand.c Incorrect FIT image format 2315 151 common/cmd_nand.c FIT image format OK 2316 2317- Standalone program support: 2318 CONFIG_STANDALONE_LOAD_ADDR 2319 2320 This option defines a board specific value for the 2321 address where standalone program gets loaded, thus 2322 overwriting the architecture dependent default 2323 settings. 2324 2325- Frame Buffer Address: 2326 CONFIG_FB_ADDR 2327 2328 Define CONFIG_FB_ADDR if you want to use specific 2329 address for frame buffer. This is typically the case 2330 when using a graphics controller has separate video 2331 memory. U-Boot will then place the frame buffer at 2332 the given address instead of dynamically reserving it 2333 in system RAM by calling lcd_setmem(), which grabs 2334 the memory for the frame buffer depending on the 2335 configured panel size. 2336 2337 Please see board_init_f function. 2338 2339- Automatic software updates via TFTP server 2340 CONFIG_UPDATE_TFTP 2341 CONFIG_UPDATE_TFTP_CNT_MAX 2342 CONFIG_UPDATE_TFTP_MSEC_MAX 2343 2344 These options enable and control the auto-update feature; 2345 for a more detailed description refer to doc/README.update. 2346 2347- MTD Support (mtdparts command, UBI support) 2348 CONFIG_MTD_UBI_WL_THRESHOLD 2349 This parameter defines the maximum difference between the highest 2350 erase counter value and the lowest erase counter value of eraseblocks 2351 of UBI devices. When this threshold is exceeded, UBI starts performing 2352 wear leveling by means of moving data from eraseblock with low erase 2353 counter to eraseblocks with high erase counter. 2354 2355 The default value should be OK for SLC NAND flashes, NOR flashes and 2356 other flashes which have eraseblock life-cycle 100000 or more. 2357 However, in case of MLC NAND flashes which typically have eraseblock 2358 life-cycle less than 10000, the threshold should be lessened (e.g., 2359 to 128 or 256, although it does not have to be power of 2). 2360 2361 default: 4096 2362 2363 CONFIG_MTD_UBI_BEB_LIMIT 2364 This option specifies the maximum bad physical eraseblocks UBI 2365 expects on the MTD device (per 1024 eraseblocks). If the 2366 underlying flash does not admit of bad eraseblocks (e.g. NOR 2367 flash), this value is ignored. 2368 2369 NAND datasheets often specify the minimum and maximum NVM 2370 (Number of Valid Blocks) for the flashes' endurance lifetime. 2371 The maximum expected bad eraseblocks per 1024 eraseblocks 2372 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2373 which gives 20 for most NANDs (MaxNVB is basically the total 2374 count of eraseblocks on the chip). 2375 2376 To put it differently, if this value is 20, UBI will try to 2377 reserve about 1.9% of physical eraseblocks for bad blocks 2378 handling. And that will be 1.9% of eraseblocks on the entire 2379 NAND chip, not just the MTD partition UBI attaches. This means 2380 that if you have, say, a NAND flash chip admits maximum 40 bad 2381 eraseblocks, and it is split on two MTD partitions of the same 2382 size, UBI will reserve 40 eraseblocks when attaching a 2383 partition. 2384 2385 default: 20 2386 2387 CONFIG_MTD_UBI_FASTMAP 2388 Fastmap is a mechanism which allows attaching an UBI device 2389 in nearly constant time. Instead of scanning the whole MTD device it 2390 only has to locate a checkpoint (called fastmap) on the device. 2391 The on-flash fastmap contains all information needed to attach 2392 the device. Using fastmap makes only sense on large devices where 2393 attaching by scanning takes long. UBI will not automatically install 2394 a fastmap on old images, but you can set the UBI parameter 2395 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2396 that fastmap-enabled images are still usable with UBI implementations 2397 without fastmap support. On typical flash devices the whole fastmap 2398 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2399 2400 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2401 Set this parameter to enable fastmap automatically on images 2402 without a fastmap. 2403 default: 0 2404 2405 CONFIG_MTD_UBI_FM_DEBUG 2406 Enable UBI fastmap debug 2407 default: 0 2408 2409- SPL framework 2410 CONFIG_SPL 2411 Enable building of SPL globally. 2412 2413 CONFIG_SPL_LDSCRIPT 2414 LDSCRIPT for linking the SPL binary. 2415 2416 CONFIG_SPL_MAX_FOOTPRINT 2417 Maximum size in memory allocated to the SPL, BSS included. 2418 When defined, the linker checks that the actual memory 2419 used by SPL from _start to __bss_end does not exceed it. 2420 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2421 must not be both defined at the same time. 2422 2423 CONFIG_SPL_MAX_SIZE 2424 Maximum size of the SPL image (text, data, rodata, and 2425 linker lists sections), BSS excluded. 2426 When defined, the linker checks that the actual size does 2427 not exceed it. 2428 2429 CONFIG_SPL_TEXT_BASE 2430 TEXT_BASE for linking the SPL binary. 2431 2432 CONFIG_SPL_RELOC_TEXT_BASE 2433 Address to relocate to. If unspecified, this is equal to 2434 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2435 2436 CONFIG_SPL_BSS_START_ADDR 2437 Link address for the BSS within the SPL binary. 2438 2439 CONFIG_SPL_BSS_MAX_SIZE 2440 Maximum size in memory allocated to the SPL BSS. 2441 When defined, the linker checks that the actual memory used 2442 by SPL from __bss_start to __bss_end does not exceed it. 2443 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2444 must not be both defined at the same time. 2445 2446 CONFIG_SPL_STACK 2447 Adress of the start of the stack SPL will use 2448 2449 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2450 When defined, SPL will panic() if the image it has 2451 loaded does not have a signature. 2452 Defining this is useful when code which loads images 2453 in SPL cannot guarantee that absolutely all read errors 2454 will be caught. 2455 An example is the LPC32XX MLC NAND driver, which will 2456 consider that a completely unreadable NAND block is bad, 2457 and thus should be skipped silently. 2458 2459 CONFIG_SPL_RELOC_STACK 2460 Adress of the start of the stack SPL will use after 2461 relocation. If unspecified, this is equal to 2462 CONFIG_SPL_STACK. 2463 2464 CONFIG_SYS_SPL_MALLOC_START 2465 Starting address of the malloc pool used in SPL. 2466 When this option is set the full malloc is used in SPL and 2467 it is set up by spl_init() and before that, the simple malloc() 2468 can be used if CONFIG_SYS_MALLOC_F is defined. 2469 2470 CONFIG_SYS_SPL_MALLOC_SIZE 2471 The size of the malloc pool used in SPL. 2472 2473 CONFIG_SPL_OS_BOOT 2474 Enable booting directly to an OS from SPL. 2475 See also: doc/README.falcon 2476 2477 CONFIG_SPL_DISPLAY_PRINT 2478 For ARM, enable an optional function to print more information 2479 about the running system. 2480 2481 CONFIG_SPL_INIT_MINIMAL 2482 Arch init code should be built for a very small image 2483 2484 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2485 Partition on the MMC to load U-Boot from when the MMC is being 2486 used in raw mode 2487 2488 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2489 Sector to load kernel uImage from when MMC is being 2490 used in raw mode (for Falcon mode) 2491 2492 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2493 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2494 Sector and number of sectors to load kernel argument 2495 parameters from when MMC is being used in raw mode 2496 (for falcon mode) 2497 2498 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 2499 Partition on the MMC to load U-Boot from when the MMC is being 2500 used in fs mode 2501 2502 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2503 Filename to read to load U-Boot when reading from filesystem 2504 2505 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2506 Filename to read to load kernel uImage when reading 2507 from filesystem (for Falcon mode) 2508 2509 CONFIG_SPL_FS_LOAD_ARGS_NAME 2510 Filename to read to load kernel argument parameters 2511 when reading from filesystem (for Falcon mode) 2512 2513 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2514 Set this for NAND SPL on PPC mpc83xx targets, so that 2515 start.S waits for the rest of the SPL to load before 2516 continuing (the hardware starts execution after just 2517 loading the first page rather than the full 4K). 2518 2519 CONFIG_SPL_SKIP_RELOCATE 2520 Avoid SPL relocation 2521 2522 CONFIG_SPL_NAND_BASE 2523 Include nand_base.c in the SPL. Requires 2524 CONFIG_SPL_NAND_DRIVERS. 2525 2526 CONFIG_SPL_NAND_DRIVERS 2527 SPL uses normal NAND drivers, not minimal drivers. 2528 2529 CONFIG_SPL_NAND_IDENT 2530 SPL uses the chip ID list to identify the NAND flash. 2531 Requires CONFIG_SPL_NAND_BASE. 2532 2533 CONFIG_SPL_NAND_ECC 2534 Include standard software ECC in the SPL 2535 2536 CONFIG_SPL_NAND_SIMPLE 2537 Support for NAND boot using simple NAND drivers that 2538 expose the cmd_ctrl() interface. 2539 2540 CONFIG_SPL_UBI 2541 Support for a lightweight UBI (fastmap) scanner and 2542 loader 2543 2544 CONFIG_SPL_NAND_RAW_ONLY 2545 Support to boot only raw u-boot.bin images. Use this only 2546 if you need to save space. 2547 2548 CONFIG_SPL_COMMON_INIT_DDR 2549 Set for common ddr init with serial presence detect in 2550 SPL binary. 2551 2552 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2553 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2554 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2555 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2556 CONFIG_SYS_NAND_ECCBYTES 2557 Defines the size and behavior of the NAND that SPL uses 2558 to read U-Boot 2559 2560 CONFIG_SPL_NAND_BOOT 2561 Add support NAND boot 2562 2563 CONFIG_SYS_NAND_U_BOOT_OFFS 2564 Location in NAND to read U-Boot from 2565 2566 CONFIG_SYS_NAND_U_BOOT_DST 2567 Location in memory to load U-Boot to 2568 2569 CONFIG_SYS_NAND_U_BOOT_SIZE 2570 Size of image to load 2571 2572 CONFIG_SYS_NAND_U_BOOT_START 2573 Entry point in loaded image to jump to 2574 2575 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2576 Define this if you need to first read the OOB and then the 2577 data. This is used, for example, on davinci platforms. 2578 2579 CONFIG_SPL_RAM_DEVICE 2580 Support for running image already present in ram, in SPL binary 2581 2582 CONFIG_SPL_PAD_TO 2583 Image offset to which the SPL should be padded before appending 2584 the SPL payload. By default, this is defined as 2585 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2586 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2587 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2588 2589 CONFIG_SPL_TARGET 2590 Final target image containing SPL and payload. Some SPLs 2591 use an arch-specific makefile fragment instead, for 2592 example if more than one image needs to be produced. 2593 2594 CONFIG_SPL_FIT_PRINT 2595 Printing information about a FIT image adds quite a bit of 2596 code to SPL. So this is normally disabled in SPL. Use this 2597 option to re-enable it. This will affect the output of the 2598 bootm command when booting a FIT image. 2599 2600- TPL framework 2601 CONFIG_TPL 2602 Enable building of TPL globally. 2603 2604 CONFIG_TPL_PAD_TO 2605 Image offset to which the TPL should be padded before appending 2606 the TPL payload. By default, this is defined as 2607 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2608 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2609 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2610 2611- Interrupt support (PPC): 2612 2613 There are common interrupt_init() and timer_interrupt() 2614 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2615 for CPU specific initialization. interrupt_init_cpu() 2616 should set decrementer_count to appropriate value. If 2617 CPU resets decrementer automatically after interrupt 2618 (ppc4xx) it should set decrementer_count to zero. 2619 timer_interrupt() calls timer_interrupt_cpu() for CPU 2620 specific handling. If board has watchdog / status_led 2621 / other_activity_monitor it works automatically from 2622 general timer_interrupt(). 2623 2624 2625Board initialization settings: 2626------------------------------ 2627 2628During Initialization u-boot calls a number of board specific functions 2629to allow the preparation of board specific prerequisites, e.g. pin setup 2630before drivers are initialized. To enable these callbacks the 2631following configuration macros have to be defined. Currently this is 2632architecture specific, so please check arch/your_architecture/lib/board.c 2633typically in board_init_f() and board_init_r(). 2634 2635- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2636- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2637- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2638- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2639 2640Configuration Settings: 2641----------------------- 2642 2643- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2644 Optionally it can be defined to support 64-bit memory commands. 2645 2646- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2647 undefine this when you're short of memory. 2648 2649- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2650 width of the commands listed in the 'help' command output. 2651 2652- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2653 prompt for user input. 2654 2655- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2656 2657- CONFIG_SYS_PBSIZE: Buffer size for Console output 2658 2659- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2660 2661- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2662 the application (usually a Linux kernel) when it is 2663 booted 2664 2665- CONFIG_SYS_BAUDRATE_TABLE: 2666 List of legal baudrate settings for this board. 2667 2668- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: 2669 Begin and End addresses of the area used by the 2670 simple memory test. 2671 2672- CONFIG_SYS_MEMTEST_SCRATCH: 2673 Scratch address used by the alternate memory test 2674 You only need to set this if address zero isn't writeable 2675 2676- CONFIG_SYS_MEM_RESERVE_SECURE 2677 Only implemented for ARMv8 for now. 2678 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2679 is substracted from total RAM and won't be reported to OS. 2680 This memory can be used as secure memory. A variable 2681 gd->arch.secure_ram is used to track the location. In systems 2682 the RAM base is not zero, or RAM is divided into banks, 2683 this variable needs to be recalcuated to get the address. 2684 2685- CONFIG_SYS_MEM_TOP_HIDE: 2686 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2687 this specified memory area will get subtracted from the top 2688 (end) of RAM and won't get "touched" at all by U-Boot. By 2689 fixing up gd->ram_size the Linux kernel should gets passed 2690 the now "corrected" memory size and won't touch it either. 2691 This should work for arch/ppc and arch/powerpc. Only Linux 2692 board ports in arch/powerpc with bootwrapper support that 2693 recalculate the memory size from the SDRAM controller setup 2694 will have to get fixed in Linux additionally. 2695 2696 This option can be used as a workaround for the 440EPx/GRx 2697 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2698 be touched. 2699 2700 WARNING: Please make sure that this value is a multiple of 2701 the Linux page size (normally 4k). If this is not the case, 2702 then the end address of the Linux memory will be located at a 2703 non page size aligned address and this could cause major 2704 problems. 2705 2706- CONFIG_SYS_LOADS_BAUD_CHANGE: 2707 Enable temporary baudrate change while serial download 2708 2709- CONFIG_SYS_SDRAM_BASE: 2710 Physical start address of SDRAM. _Must_ be 0 here. 2711 2712- CONFIG_SYS_FLASH_BASE: 2713 Physical start address of Flash memory. 2714 2715- CONFIG_SYS_MONITOR_BASE: 2716 Physical start address of boot monitor code (set by 2717 make config files to be same as the text base address 2718 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2719 CONFIG_SYS_FLASH_BASE when booting from flash. 2720 2721- CONFIG_SYS_MONITOR_LEN: 2722 Size of memory reserved for monitor code, used to 2723 determine _at_compile_time_ (!) if the environment is 2724 embedded within the U-Boot image, or in a separate 2725 flash sector. 2726 2727- CONFIG_SYS_MALLOC_LEN: 2728 Size of DRAM reserved for malloc() use. 2729 2730- CONFIG_SYS_MALLOC_F_LEN 2731 Size of the malloc() pool for use before relocation. If 2732 this is defined, then a very simple malloc() implementation 2733 will become available before relocation. The address is just 2734 below the global data, and the stack is moved down to make 2735 space. 2736 2737 This feature allocates regions with increasing addresses 2738 within the region. calloc() is supported, but realloc() 2739 is not available. free() is supported but does nothing. 2740 The memory will be freed (or in fact just forgotten) when 2741 U-Boot relocates itself. 2742 2743- CONFIG_SYS_MALLOC_SIMPLE 2744 Provides a simple and small malloc() and calloc() for those 2745 boards which do not use the full malloc in SPL (which is 2746 enabled with CONFIG_SYS_SPL_MALLOC_START). 2747 2748- CONFIG_SYS_NONCACHED_MEMORY: 2749 Size of non-cached memory area. This area of memory will be 2750 typically located right below the malloc() area and mapped 2751 uncached in the MMU. This is useful for drivers that would 2752 otherwise require a lot of explicit cache maintenance. For 2753 some drivers it's also impossible to properly maintain the 2754 cache. For example if the regions that need to be flushed 2755 are not a multiple of the cache-line size, *and* padding 2756 cannot be allocated between the regions to align them (i.e. 2757 if the HW requires a contiguous array of regions, and the 2758 size of each region is not cache-aligned), then a flush of 2759 one region may result in overwriting data that hardware has 2760 written to another region in the same cache-line. This can 2761 happen for example in network drivers where descriptors for 2762 buffers are typically smaller than the CPU cache-line (e.g. 2763 16 bytes vs. 32 or 64 bytes). 2764 2765 Non-cached memory is only supported on 32-bit ARM at present. 2766 2767- CONFIG_SYS_BOOTM_LEN: 2768 Normally compressed uImages are limited to an 2769 uncompressed size of 8 MBytes. If this is not enough, 2770 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2771 to adjust this setting to your needs. 2772 2773- CONFIG_SYS_BOOTMAPSZ: 2774 Maximum size of memory mapped by the startup code of 2775 the Linux kernel; all data that must be processed by 2776 the Linux kernel (bd_info, boot arguments, FDT blob if 2777 used) must be put below this limit, unless "bootm_low" 2778 environment variable is defined and non-zero. In such case 2779 all data for the Linux kernel must be between "bootm_low" 2780 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2781 variable "bootm_mapsize" will override the value of 2782 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2783 then the value in "bootm_size" will be used instead. 2784 2785- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2786 Enable initrd_high functionality. If defined then the 2787 initrd_high feature is enabled and the bootm ramdisk subcommand 2788 is enabled. 2789 2790- CONFIG_SYS_BOOT_GET_CMDLINE: 2791 Enables allocating and saving kernel cmdline in space between 2792 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2793 2794- CONFIG_SYS_BOOT_GET_KBD: 2795 Enables allocating and saving a kernel copy of the bd_info in 2796 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2797 2798- CONFIG_SYS_MAX_FLASH_BANKS: 2799 Max number of Flash memory banks 2800 2801- CONFIG_SYS_MAX_FLASH_SECT: 2802 Max number of sectors on a Flash chip 2803 2804- CONFIG_SYS_FLASH_ERASE_TOUT: 2805 Timeout for Flash erase operations (in ms) 2806 2807- CONFIG_SYS_FLASH_WRITE_TOUT: 2808 Timeout for Flash write operations (in ms) 2809 2810- CONFIG_SYS_FLASH_LOCK_TOUT 2811 Timeout for Flash set sector lock bit operation (in ms) 2812 2813- CONFIG_SYS_FLASH_UNLOCK_TOUT 2814 Timeout for Flash clear lock bits operation (in ms) 2815 2816- CONFIG_SYS_FLASH_PROTECTION 2817 If defined, hardware flash sectors protection is used 2818 instead of U-Boot software protection. 2819 2820- CONFIG_SYS_DIRECT_FLASH_TFTP: 2821 2822 Enable TFTP transfers directly to flash memory; 2823 without this option such a download has to be 2824 performed in two steps: (1) download to RAM, and (2) 2825 copy from RAM to flash. 2826 2827 The two-step approach is usually more reliable, since 2828 you can check if the download worked before you erase 2829 the flash, but in some situations (when system RAM is 2830 too limited to allow for a temporary copy of the 2831 downloaded image) this option may be very useful. 2832 2833- CONFIG_SYS_FLASH_CFI: 2834 Define if the flash driver uses extra elements in the 2835 common flash structure for storing flash geometry. 2836 2837- CONFIG_FLASH_CFI_DRIVER 2838 This option also enables the building of the cfi_flash driver 2839 in the drivers directory 2840 2841- CONFIG_FLASH_CFI_MTD 2842 This option enables the building of the cfi_mtd driver 2843 in the drivers directory. The driver exports CFI flash 2844 to the MTD layer. 2845 2846- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2847 Use buffered writes to flash. 2848 2849- CONFIG_FLASH_SPANSION_S29WS_N 2850 s29ws-n MirrorBit flash has non-standard addresses for buffered 2851 write commands. 2852 2853- CONFIG_SYS_FLASH_QUIET_TEST 2854 If this option is defined, the common CFI flash doesn't 2855 print it's warning upon not recognized FLASH banks. This 2856 is useful, if some of the configured banks are only 2857 optionally available. 2858 2859- CONFIG_FLASH_SHOW_PROGRESS 2860 If defined (must be an integer), print out countdown 2861 digits and dots. Recommended value: 45 (9..1) for 80 2862 column displays, 15 (3..1) for 40 column displays. 2863 2864- CONFIG_FLASH_VERIFY 2865 If defined, the content of the flash (destination) is compared 2866 against the source after the write operation. An error message 2867 will be printed when the contents are not identical. 2868 Please note that this option is useless in nearly all cases, 2869 since such flash programming errors usually are detected earlier 2870 while unprotecting/erasing/programming. Please only enable 2871 this option if you really know what you are doing. 2872 2873- CONFIG_SYS_RX_ETH_BUFFER: 2874 Defines the number of Ethernet receive buffers. On some 2875 Ethernet controllers it is recommended to set this value 2876 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2877 buffers can be full shortly after enabling the interface 2878 on high Ethernet traffic. 2879 Defaults to 4 if not defined. 2880 2881- CONFIG_ENV_MAX_ENTRIES 2882 2883 Maximum number of entries in the hash table that is used 2884 internally to store the environment settings. The default 2885 setting is supposed to be generous and should work in most 2886 cases. This setting can be used to tune behaviour; see 2887 lib/hashtable.c for details. 2888 2889- CONFIG_ENV_FLAGS_LIST_DEFAULT 2890- CONFIG_ENV_FLAGS_LIST_STATIC 2891 Enable validation of the values given to environment variables when 2892 calling env set. Variables can be restricted to only decimal, 2893 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2894 the variables can also be restricted to IP address or MAC address. 2895 2896 The format of the list is: 2897 type_attribute = [s|d|x|b|i|m] 2898 access_attribute = [a|r|o|c] 2899 attributes = type_attribute[access_attribute] 2900 entry = variable_name[:attributes] 2901 list = entry[,list] 2902 2903 The type attributes are: 2904 s - String (default) 2905 d - Decimal 2906 x - Hexadecimal 2907 b - Boolean ([1yYtT|0nNfF]) 2908 i - IP address 2909 m - MAC address 2910 2911 The access attributes are: 2912 a - Any (default) 2913 r - Read-only 2914 o - Write-once 2915 c - Change-default 2916 2917 - CONFIG_ENV_FLAGS_LIST_DEFAULT 2918 Define this to a list (string) to define the ".flags" 2919 environment variable in the default or embedded environment. 2920 2921 - CONFIG_ENV_FLAGS_LIST_STATIC 2922 Define this to a list (string) to define validation that 2923 should be done if an entry is not found in the ".flags" 2924 environment variable. To override a setting in the static 2925 list, simply add an entry for the same variable name to the 2926 ".flags" variable. 2927 2928 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 2929 regular expression. This allows multiple variables to define the same 2930 flags without explicitly listing them for each variable. 2931 2932- CONFIG_ENV_ACCESS_IGNORE_FORCE 2933 If defined, don't allow the -f switch to env set override variable 2934 access flags. 2935 2936The following definitions that deal with the placement and management 2937of environment data (variable area); in general, we support the 2938following configurations: 2939 2940- CONFIG_BUILD_ENVCRC: 2941 2942 Builds up envcrc with the target environment so that external utils 2943 may easily extract it and embed it in final U-Boot images. 2944 2945BE CAREFUL! The first access to the environment happens quite early 2946in U-Boot initialization (when we try to get the setting of for the 2947console baudrate). You *MUST* have mapped your NVRAM area then, or 2948U-Boot will hang. 2949 2950Please note that even with NVRAM we still use a copy of the 2951environment in RAM: we could work on NVRAM directly, but we want to 2952keep settings there always unmodified except somebody uses "saveenv" 2953to save the current settings. 2954 2955BE CAREFUL! For some special cases, the local device can not use 2956"saveenv" command. For example, the local device will get the 2957environment stored in a remote NOR flash by SRIO or PCIE link, 2958but it can not erase, write this NOR flash by SRIO or PCIE interface. 2959 2960- CONFIG_NAND_ENV_DST 2961 2962 Defines address in RAM to which the nand_spl code should copy the 2963 environment. If redundant environment is used, it will be copied to 2964 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 2965 2966Please note that the environment is read-only until the monitor 2967has been relocated to RAM and a RAM copy of the environment has been 2968created; also, when using EEPROM you will have to use env_get_f() 2969until then to read environment variables. 2970 2971The environment is protected by a CRC32 checksum. Before the monitor 2972is relocated into RAM, as a result of a bad CRC you will be working 2973with the compiled-in default environment - *silently*!!! [This is 2974necessary, because the first environment variable we need is the 2975"baudrate" setting for the console - if we have a bad CRC, we don't 2976have any device yet where we could complain.] 2977 2978Note: once the monitor has been relocated, then it will complain if 2979the default environment is used; a new CRC is computed as soon as you 2980use the "saveenv" command to store a valid environment. 2981 2982- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 2983 Echo the inverted Ethernet link state to the fault LED. 2984 2985 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 2986 also needs to be defined. 2987 2988- CONFIG_SYS_FAULT_MII_ADDR: 2989 MII address of the PHY to check for the Ethernet link state. 2990 2991- CONFIG_NS16550_MIN_FUNCTIONS: 2992 Define this if you desire to only have use of the NS16550_init 2993 and NS16550_putc functions for the serial driver located at 2994 drivers/serial/ns16550.c. This option is useful for saving 2995 space for already greatly restricted images, including but not 2996 limited to NAND_SPL configurations. 2997 2998- CONFIG_DISPLAY_BOARDINFO 2999 Display information about the board that U-Boot is running on 3000 when U-Boot starts up. The board function checkboard() is called 3001 to do this. 3002 3003- CONFIG_DISPLAY_BOARDINFO_LATE 3004 Similar to the previous option, but display this information 3005 later, once stdio is running and output goes to the LCD, if 3006 present. 3007 3008- CONFIG_BOARD_SIZE_LIMIT: 3009 Maximum size of the U-Boot image. When defined, the 3010 build system checks that the actual size does not 3011 exceed it. 3012 3013Low Level (hardware related) configuration options: 3014--------------------------------------------------- 3015 3016- CONFIG_SYS_CACHELINE_SIZE: 3017 Cache Line Size of the CPU. 3018 3019- CONFIG_SYS_CCSRBAR_DEFAULT: 3020 Default (power-on reset) physical address of CCSR on Freescale 3021 PowerPC SOCs. 3022 3023- CONFIG_SYS_CCSRBAR: 3024 Virtual address of CCSR. On a 32-bit build, this is typically 3025 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 3026 3027- CONFIG_SYS_CCSRBAR_PHYS: 3028 Physical address of CCSR. CCSR can be relocated to a new 3029 physical address, if desired. In this case, this macro should 3030 be set to that address. Otherwise, it should be set to the 3031 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 3032 is typically relocated on 36-bit builds. It is recommended 3033 that this macro be defined via the _HIGH and _LOW macros: 3034 3035 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 3036 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 3037 3038- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 3039 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 3040 either 0 (32-bit build) or 0xF (36-bit build). This macro is 3041 used in assembly code, so it must not contain typecasts or 3042 integer size suffixes (e.g. "ULL"). 3043 3044- CONFIG_SYS_CCSRBAR_PHYS_LOW: 3045 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 3046 used in assembly code, so it must not contain typecasts or 3047 integer size suffixes (e.g. "ULL"). 3048 3049- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 3050 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 3051 forced to a value that ensures that CCSR is not relocated. 3052 3053- Floppy Disk Support: 3054 CONFIG_SYS_FDC_DRIVE_NUMBER 3055 3056 the default drive number (default value 0) 3057 3058 CONFIG_SYS_ISA_IO_STRIDE 3059 3060 defines the spacing between FDC chipset registers 3061 (default value 1) 3062 3063 CONFIG_SYS_ISA_IO_OFFSET 3064 3065 defines the offset of register from address. It 3066 depends on which part of the data bus is connected to 3067 the FDC chipset. (default value 0) 3068 3069 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and 3070 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their 3071 default value. 3072 3073 if CONFIG_SYS_FDC_HW_INIT is defined, then the function 3074 fdc_hw_init() is called at the beginning of the FDC 3075 setup. fdc_hw_init() must be provided by the board 3076 source code. It is used to make hardware-dependent 3077 initializations. 3078 3079- CONFIG_IDE_AHB: 3080 Most IDE controllers were designed to be connected with PCI 3081 interface. Only few of them were designed for AHB interface. 3082 When software is doing ATA command and data transfer to 3083 IDE devices through IDE-AHB controller, some additional 3084 registers accessing to these kind of IDE-AHB controller 3085 is required. 3086 3087- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 3088 DO NOT CHANGE unless you know exactly what you're 3089 doing! (11-4) [MPC8xx systems only] 3090 3091- CONFIG_SYS_INIT_RAM_ADDR: 3092 3093 Start address of memory area that can be used for 3094 initial data and stack; please note that this must be 3095 writable memory that is working WITHOUT special 3096 initialization, i. e. you CANNOT use normal RAM which 3097 will become available only after programming the 3098 memory controller and running certain initialization 3099 sequences. 3100 3101 U-Boot uses the following memory types: 3102 - MPC8xx: IMMR (internal memory of the CPU) 3103 3104- CONFIG_SYS_GBL_DATA_OFFSET: 3105 3106 Offset of the initial data structure in the memory 3107 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 3108 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 3109 data is located at the end of the available space 3110 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 3111 GENERATED_GBL_DATA_SIZE), and the initial stack is just 3112 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 3113 CONFIG_SYS_GBL_DATA_OFFSET) downward. 3114 3115 Note: 3116 On the MPC824X (or other systems that use the data 3117 cache for initial memory) the address chosen for 3118 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 3119 point to an otherwise UNUSED address space between 3120 the top of RAM and the start of the PCI space. 3121 3122- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 3123 3124- CONFIG_SYS_OR_TIMING_SDRAM: 3125 SDRAM timing 3126 3127- CONFIG_SYS_MAMR_PTA: 3128 periodic timer for refresh 3129 3130- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 3131 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 3132 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 3133 CONFIG_SYS_BR1_PRELIM: 3134 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 3135 3136- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 3137 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 3138 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 3139 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 3140 3141- CONFIG_PCI_ENUM_ONLY 3142 Only scan through and get the devices on the buses. 3143 Don't do any setup work, presumably because someone or 3144 something has already done it, and we don't need to do it 3145 a second time. Useful for platforms that are pre-booted 3146 by coreboot or similar. 3147 3148- CONFIG_PCI_INDIRECT_BRIDGE: 3149 Enable support for indirect PCI bridges. 3150 3151- CONFIG_SYS_SRIO: 3152 Chip has SRIO or not 3153 3154- CONFIG_SRIO1: 3155 Board has SRIO 1 port available 3156 3157- CONFIG_SRIO2: 3158 Board has SRIO 2 port available 3159 3160- CONFIG_SRIO_PCIE_BOOT_MASTER 3161 Board can support master function for Boot from SRIO and PCIE 3162 3163- CONFIG_SYS_SRIOn_MEM_VIRT: 3164 Virtual Address of SRIO port 'n' memory region 3165 3166- CONFIG_SYS_SRIOn_MEM_PHYS: 3167 Physical Address of SRIO port 'n' memory region 3168 3169- CONFIG_SYS_SRIOn_MEM_SIZE: 3170 Size of SRIO port 'n' memory region 3171 3172- CONFIG_SYS_NAND_BUSWIDTH_16BIT 3173 Defined to tell the NAND controller that the NAND chip is using 3174 a 16 bit bus. 3175 Not all NAND drivers use this symbol. 3176 Example of drivers that use it: 3177 - drivers/mtd/nand/raw/ndfc.c 3178 - drivers/mtd/nand/raw/mxc_nand.c 3179 3180- CONFIG_SYS_NDFC_EBC0_CFG 3181 Sets the EBC0_CFG register for the NDFC. If not defined 3182 a default value will be used. 3183 3184- CONFIG_SPD_EEPROM 3185 Get DDR timing information from an I2C EEPROM. Common 3186 with pluggable memory modules such as SODIMMs 3187 3188 SPD_EEPROM_ADDRESS 3189 I2C address of the SPD EEPROM 3190 3191- CONFIG_SYS_SPD_BUS_NUM 3192 If SPD EEPROM is on an I2C bus other than the first 3193 one, specify here. Note that the value must resolve 3194 to something your driver can deal with. 3195 3196- CONFIG_SYS_DDR_RAW_TIMING 3197 Get DDR timing information from other than SPD. Common with 3198 soldered DDR chips onboard without SPD. DDR raw timing 3199 parameters are extracted from datasheet and hard-coded into 3200 header files or board specific files. 3201 3202- CONFIG_FSL_DDR_INTERACTIVE 3203 Enable interactive DDR debugging. See doc/README.fsl-ddr. 3204 3205- CONFIG_FSL_DDR_SYNC_REFRESH 3206 Enable sync of refresh for multiple controllers. 3207 3208- CONFIG_FSL_DDR_BIST 3209 Enable built-in memory test for Freescale DDR controllers. 3210 3211- CONFIG_SYS_83XX_DDR_USES_CS0 3212 Only for 83xx systems. If specified, then DDR should 3213 be configured using CS0 and CS1 instead of CS2 and CS3. 3214 3215- CONFIG_RMII 3216 Enable RMII mode for all FECs. 3217 Note that this is a global option, we can't 3218 have one FEC in standard MII mode and another in RMII mode. 3219 3220- CONFIG_CRC32_VERIFY 3221 Add a verify option to the crc32 command. 3222 The syntax is: 3223 3224 => crc32 -v <address> <count> <crc32> 3225 3226 Where address/count indicate a memory area 3227 and crc32 is the correct crc32 which the 3228 area should have. 3229 3230- CONFIG_LOOPW 3231 Add the "loopw" memory command. This only takes effect if 3232 the memory commands are activated globally (CONFIG_CMD_MEMORY). 3233 3234- CONFIG_MX_CYCLIC 3235 Add the "mdc" and "mwc" memory commands. These are cyclic 3236 "md/mw" commands. 3237 Examples: 3238 3239 => mdc.b 10 4 500 3240 This command will print 4 bytes (10,11,12,13) each 500 ms. 3241 3242 => mwc.l 100 12345678 10 3243 This command will write 12345678 to address 100 all 10 ms. 3244 3245 This only takes effect if the memory commands are activated 3246 globally (CONFIG_CMD_MEMORY). 3247 3248- CONFIG_SKIP_LOWLEVEL_INIT 3249 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 3250 low level initializations (like setting up the memory 3251 controller) are omitted and/or U-Boot does not 3252 relocate itself into RAM. 3253 3254 Normally this variable MUST NOT be defined. The only 3255 exception is when U-Boot is loaded (to RAM) by some 3256 other boot loader or by a debugger which performs 3257 these initializations itself. 3258 3259- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 3260 [ARM926EJ-S only] This allows just the call to lowlevel_init() 3261 to be skipped. The normal CP15 init (such as enabling the 3262 instruction cache) is still performed. 3263 3264- CONFIG_SPL_BUILD 3265 Modifies the behaviour of start.S when compiling a loader 3266 that is executed before the actual U-Boot. E.g. when 3267 compiling a NAND SPL. 3268 3269- CONFIG_TPL_BUILD 3270 Modifies the behaviour of start.S when compiling a loader 3271 that is executed after the SPL and before the actual U-Boot. 3272 It is loaded by the SPL. 3273 3274- CONFIG_SYS_MPC85XX_NO_RESETVEC 3275 Only for 85xx systems. If this variable is specified, the section 3276 .resetvec is not kept and the section .bootpg is placed in the 3277 previous 4k of the .text section. 3278 3279- CONFIG_ARCH_MAP_SYSMEM 3280 Generally U-Boot (and in particular the md command) uses 3281 effective address. It is therefore not necessary to regard 3282 U-Boot address as virtual addresses that need to be translated 3283 to physical addresses. However, sandbox requires this, since 3284 it maintains its own little RAM buffer which contains all 3285 addressable memory. This option causes some memory accesses 3286 to be mapped through map_sysmem() / unmap_sysmem(). 3287 3288- CONFIG_X86_RESET_VECTOR 3289 If defined, the x86 reset vector code is included. This is not 3290 needed when U-Boot is running from Coreboot. 3291 3292- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 3293 Option to disable subpage write in NAND driver 3294 driver that uses this: 3295 drivers/mtd/nand/raw/davinci_nand.c 3296 3297Freescale QE/FMAN Firmware Support: 3298----------------------------------- 3299 3300The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 3301loading of "firmware", which is encoded in the QE firmware binary format. 3302This firmware often needs to be loaded during U-Boot booting, so macros 3303are used to identify the storage device (NOR flash, SPI, etc) and the address 3304within that device. 3305 3306- CONFIG_SYS_FMAN_FW_ADDR 3307 The address in the storage device where the FMAN microcode is located. The 3308 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3309 is also specified. 3310 3311- CONFIG_SYS_QE_FW_ADDR 3312 The address in the storage device where the QE microcode is located. The 3313 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3314 is also specified. 3315 3316- CONFIG_SYS_QE_FMAN_FW_LENGTH 3317 The maximum possible size of the firmware. The firmware binary format 3318 has a field that specifies the actual size of the firmware, but it 3319 might not be possible to read any part of the firmware unless some 3320 local storage is allocated to hold the entire firmware first. 3321 3322- CONFIG_SYS_QE_FMAN_FW_IN_NOR 3323 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 3324 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 3325 virtual address in NOR flash. 3326 3327- CONFIG_SYS_QE_FMAN_FW_IN_NAND 3328 Specifies that QE/FMAN firmware is located in NAND flash. 3329 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 3330 3331- CONFIG_SYS_QE_FMAN_FW_IN_MMC 3332 Specifies that QE/FMAN firmware is located on the primary SD/MMC 3333 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 3334 3335- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 3336 Specifies that QE/FMAN firmware is located in the remote (master) 3337 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 3338 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 3339 window->master inbound window->master LAW->the ucode address in 3340 master's memory space. 3341 3342Freescale Layerscape Management Complex Firmware Support: 3343--------------------------------------------------------- 3344The Freescale Layerscape Management Complex (MC) supports the loading of 3345"firmware". 3346This firmware often needs to be loaded during U-Boot booting, so macros 3347are used to identify the storage device (NOR flash, SPI, etc) and the address 3348within that device. 3349 3350- CONFIG_FSL_MC_ENET 3351 Enable the MC driver for Layerscape SoCs. 3352 3353Freescale Layerscape Debug Server Support: 3354------------------------------------------- 3355The Freescale Layerscape Debug Server Support supports the loading of 3356"Debug Server firmware" and triggering SP boot-rom. 3357This firmware often needs to be loaded during U-Boot booting. 3358 3359- CONFIG_SYS_MC_RSV_MEM_ALIGN 3360 Define alignment of reserved memory MC requires 3361 3362Reproducible builds 3363------------------- 3364 3365In order to achieve reproducible builds, timestamps used in the U-Boot build 3366process have to be set to a fixed value. 3367 3368This is done using the SOURCE_DATE_EPOCH environment variable. 3369SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3370option for U-Boot or an environment variable in U-Boot. 3371 3372SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3373 3374Building the Software: 3375====================== 3376 3377Building U-Boot has been tested in several native build environments 3378and in many different cross environments. Of course we cannot support 3379all possibly existing versions of cross development tools in all 3380(potentially obsolete) versions. In case of tool chain problems we 3381recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) 3382which is extensively used to build and test U-Boot. 3383 3384If you are not using a native environment, it is assumed that you 3385have GNU cross compiling tools available in your path. In this case, 3386you must set the environment variable CROSS_COMPILE in your shell. 3387Note that no changes to the Makefile or any other source files are 3388necessary. For example using the ELDK on a 4xx CPU, please enter: 3389 3390 $ CROSS_COMPILE=ppc_4xx- 3391 $ export CROSS_COMPILE 3392 3393Note: If you wish to generate Windows versions of the utilities in 3394 the tools directory you can use the MinGW toolchain 3395 (http://www.mingw.org). Set your HOST tools to the MinGW 3396 toolchain and execute 'make tools'. For example: 3397 3398 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools 3399 3400 Binaries such as tools/mkimage.exe will be created which can 3401 be executed on computers running Windows. 3402 3403U-Boot is intended to be simple to build. After installing the 3404sources you must configure U-Boot for one specific board type. This 3405is done by typing: 3406 3407 make NAME_defconfig 3408 3409where "NAME_defconfig" is the name of one of the existing configu- 3410rations; see boards.cfg for supported names. 3411 3412Note: for some board special configuration names may exist; check if 3413 additional information is available from the board vendor; for 3414 instance, the TQM823L systems are available without (standard) 3415 or with LCD support. You can select such additional "features" 3416 when choosing the configuration, i. e. 3417 3418 make TQM823L_defconfig 3419 - will configure for a plain TQM823L, i. e. no LCD support 3420 3421 make TQM823L_LCD_defconfig 3422 - will configure for a TQM823L with U-Boot console on LCD 3423 3424 etc. 3425 3426 3427Finally, type "make all", and you should get some working U-Boot 3428images ready for download to / installation on your system: 3429 3430- "u-boot.bin" is a raw binary image 3431- "u-boot" is an image in ELF binary format 3432- "u-boot.srec" is in Motorola S-Record format 3433 3434By default the build is performed locally and the objects are saved 3435in the source directory. One of the two methods can be used to change 3436this behavior and build U-Boot to some external directory: 3437 34381. Add O= to the make command line invocations: 3439 3440 make O=/tmp/build distclean 3441 make O=/tmp/build NAME_defconfig 3442 make O=/tmp/build all 3443 34442. Set environment variable KBUILD_OUTPUT to point to the desired location: 3445 3446 export KBUILD_OUTPUT=/tmp/build 3447 make distclean 3448 make NAME_defconfig 3449 make all 3450 3451Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3452variable. 3453 3454User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3455setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3456For example to treat all compiler warnings as errors: 3457 3458 make KCFLAGS=-Werror 3459 3460Please be aware that the Makefiles assume you are using GNU make, so 3461for instance on NetBSD you might need to use "gmake" instead of 3462native "make". 3463 3464 3465If the system board that you have is not listed, then you will need 3466to port U-Boot to your hardware platform. To do this, follow these 3467steps: 3468 34691. Create a new directory to hold your board specific code. Add any 3470 files you need. In your board directory, you will need at least 3471 the "Makefile" and a "<board>.c". 34722. Create a new configuration file "include/configs/<board>.h" for 3473 your board. 34743. If you're porting U-Boot to a new CPU, then also create a new 3475 directory to hold your CPU specific code. Add any files you need. 34764. Run "make <board>_defconfig" with your new name. 34775. Type "make", and you should get a working "u-boot.srec" file 3478 to be installed on your target system. 34796. Debug and solve any problems that might arise. 3480 [Of course, this last step is much harder than it sounds.] 3481 3482 3483Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3484============================================================== 3485 3486If you have modified U-Boot sources (for instance added a new board 3487or support for new devices, a new CPU, etc.) you are expected to 3488provide feedback to the other developers. The feedback normally takes 3489the form of a "patch", i. e. a context diff against a certain (latest 3490official or latest in the git repository) version of U-Boot sources. 3491 3492But before you submit such a patch, please verify that your modifi- 3493cation did not break existing code. At least make sure that *ALL* of 3494the supported boards compile WITHOUT ANY compiler warnings. To do so, 3495just run the buildman script (tools/buildman/buildman), which will 3496configure and build U-Boot for ALL supported system. Be warned, this 3497will take a while. Please see the buildman README, or run 'buildman -H' 3498for documentation. 3499 3500 3501See also "U-Boot Porting Guide" below. 3502 3503 3504Monitor Commands - Overview: 3505============================ 3506 3507go - start application at address 'addr' 3508run - run commands in an environment variable 3509bootm - boot application image from memory 3510bootp - boot image via network using BootP/TFTP protocol 3511bootz - boot zImage from memory 3512tftpboot- boot image via network using TFTP protocol 3513 and env variables "ipaddr" and "serverip" 3514 (and eventually "gatewayip") 3515tftpput - upload a file via network using TFTP protocol 3516rarpboot- boot image via network using RARP/TFTP protocol 3517diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3518loads - load S-Record file over serial line 3519loadb - load binary file over serial line (kermit mode) 3520md - memory display 3521mm - memory modify (auto-incrementing) 3522nm - memory modify (constant address) 3523mw - memory write (fill) 3524cp - memory copy 3525cmp - memory compare 3526crc32 - checksum calculation 3527i2c - I2C sub-system 3528sspi - SPI utility commands 3529base - print or set address offset 3530printenv- print environment variables 3531setenv - set environment variables 3532saveenv - save environment variables to persistent storage 3533protect - enable or disable FLASH write protection 3534erase - erase FLASH memory 3535flinfo - print FLASH memory information 3536nand - NAND memory operations (see doc/README.nand) 3537bdinfo - print Board Info structure 3538iminfo - print header information for application image 3539coninfo - print console devices and informations 3540ide - IDE sub-system 3541loop - infinite loop on address range 3542loopw - infinite write loop on address range 3543mtest - simple RAM test 3544icache - enable or disable instruction cache 3545dcache - enable or disable data cache 3546reset - Perform RESET of the CPU 3547echo - echo args to console 3548version - print monitor version 3549help - print online help 3550? - alias for 'help' 3551 3552 3553Monitor Commands - Detailed Description: 3554======================================== 3555 3556TODO. 3557 3558For now: just type "help <command>". 3559 3560 3561Environment Variables: 3562====================== 3563 3564U-Boot supports user configuration using Environment Variables which 3565can be made persistent by saving to Flash memory. 3566 3567Environment Variables are set using "setenv", printed using 3568"printenv", and saved to Flash using "saveenv". Using "setenv" 3569without a value can be used to delete a variable from the 3570environment. As long as you don't save the environment you are 3571working with an in-memory copy. In case the Flash area containing the 3572environment is erased by accident, a default environment is provided. 3573 3574Some configuration options can be set using Environment Variables. 3575 3576List of environment variables (most likely not complete): 3577 3578 baudrate - see CONFIG_BAUDRATE 3579 3580 bootdelay - see CONFIG_BOOTDELAY 3581 3582 bootcmd - see CONFIG_BOOTCOMMAND 3583 3584 bootargs - Boot arguments when booting an RTOS image 3585 3586 bootfile - Name of the image to load with TFTP 3587 3588 bootm_low - Memory range available for image processing in the bootm 3589 command can be restricted. This variable is given as 3590 a hexadecimal number and defines lowest address allowed 3591 for use by the bootm command. See also "bootm_size" 3592 environment variable. Address defined by "bootm_low" is 3593 also the base of the initial memory mapping for the Linux 3594 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3595 bootm_mapsize. 3596 3597 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3598 This variable is given as a hexadecimal number and it 3599 defines the size of the memory region starting at base 3600 address bootm_low that is accessible by the Linux kernel 3601 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3602 as the default value if it is defined, and bootm_size is 3603 used otherwise. 3604 3605 bootm_size - Memory range available for image processing in the bootm 3606 command can be restricted. This variable is given as 3607 a hexadecimal number and defines the size of the region 3608 allowed for use by the bootm command. See also "bootm_low" 3609 environment variable. 3610 3611 updatefile - Location of the software update file on a TFTP server, used 3612 by the automatic software update feature. Please refer to 3613 documentation in doc/README.update for more details. 3614 3615 autoload - if set to "no" (any string beginning with 'n'), 3616 "bootp" will just load perform a lookup of the 3617 configuration from the BOOTP server, but not try to 3618 load any image using TFTP 3619 3620 autostart - if set to "yes", an image loaded using the "bootp", 3621 "rarpboot", "tftpboot" or "diskboot" commands will 3622 be automatically started (by internally calling 3623 "bootm") 3624 3625 If set to "no", a standalone image passed to the 3626 "bootm" command will be copied to the load address 3627 (and eventually uncompressed), but NOT be started. 3628 This can be used to load and uncompress arbitrary 3629 data. 3630 3631 fdt_high - if set this restricts the maximum address that the 3632 flattened device tree will be copied into upon boot. 3633 For example, if you have a system with 1 GB memory 3634 at physical address 0x10000000, while Linux kernel 3635 only recognizes the first 704 MB as low memory, you 3636 may need to set fdt_high as 0x3C000000 to have the 3637 device tree blob be copied to the maximum address 3638 of the 704 MB low memory, so that Linux kernel can 3639 access it during the boot procedure. 3640 3641 If this is set to the special value 0xFFFFFFFF then 3642 the fdt will not be copied at all on boot. For this 3643 to work it must reside in writable memory, have 3644 sufficient padding on the end of it for u-boot to 3645 add the information it needs into it, and the memory 3646 must be accessible by the kernel. 3647 3648 fdtcontroladdr- if set this is the address of the control flattened 3649 device tree used by U-Boot when CONFIG_OF_CONTROL is 3650 defined. 3651 3652 i2cfast - (PPC405GP|PPC405EP only) 3653 if set to 'y' configures Linux I2C driver for fast 3654 mode (400kHZ). This environment variable is used in 3655 initialization code. So, for changes to be effective 3656 it must be saved and board must be reset. 3657 3658 initrd_high - restrict positioning of initrd images: 3659 If this variable is not set, initrd images will be 3660 copied to the highest possible address in RAM; this 3661 is usually what you want since it allows for 3662 maximum initrd size. If for some reason you want to 3663 make sure that the initrd image is loaded below the 3664 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3665 variable to a value of "no" or "off" or "0". 3666 Alternatively, you can set it to a maximum upper 3667 address to use (U-Boot will still check that it 3668 does not overwrite the U-Boot stack and data). 3669 3670 For instance, when you have a system with 16 MB 3671 RAM, and want to reserve 4 MB from use by Linux, 3672 you can do this by adding "mem=12M" to the value of 3673 the "bootargs" variable. However, now you must make 3674 sure that the initrd image is placed in the first 3675 12 MB as well - this can be done with 3676 3677 setenv initrd_high 00c00000 3678 3679 If you set initrd_high to 0xFFFFFFFF, this is an 3680 indication to U-Boot that all addresses are legal 3681 for the Linux kernel, including addresses in flash 3682 memory. In this case U-Boot will NOT COPY the 3683 ramdisk at all. This may be useful to reduce the 3684 boot time on your system, but requires that this 3685 feature is supported by your Linux kernel. 3686 3687 ipaddr - IP address; needed for tftpboot command 3688 3689 loadaddr - Default load address for commands like "bootp", 3690 "rarpboot", "tftpboot", "loadb" or "diskboot" 3691 3692 loads_echo - see CONFIG_LOADS_ECHO 3693 3694 serverip - TFTP server IP address; needed for tftpboot command 3695 3696 bootretry - see CONFIG_BOOT_RETRY_TIME 3697 3698 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3699 3700 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3701 3702 ethprime - controls which interface is used first. 3703 3704 ethact - controls which interface is currently active. 3705 For example you can do the following 3706 3707 => setenv ethact FEC 3708 => ping 192.168.0.1 # traffic sent on FEC 3709 => setenv ethact SCC 3710 => ping 10.0.0.1 # traffic sent on SCC 3711 3712 ethrotate - When set to "no" U-Boot does not go through all 3713 available network interfaces. 3714 It just stays at the currently selected interface. 3715 3716 netretry - When set to "no" each network operation will 3717 either succeed or fail without retrying. 3718 When set to "once" the network operation will 3719 fail when all the available network interfaces 3720 are tried once without success. 3721 Useful on scripts which control the retry operation 3722 themselves. 3723 3724 npe_ucode - set load address for the NPE microcode 3725 3726 silent_linux - If set then Linux will be told to boot silently, by 3727 changing the console to be empty. If "yes" it will be 3728 made silent. If "no" it will not be made silent. If 3729 unset, then it will be made silent if the U-Boot console 3730 is silent. 3731 3732 tftpsrcp - If this is set, the value is used for TFTP's 3733 UDP source port. 3734 3735 tftpdstp - If this is set, the value is used for TFTP's UDP 3736 destination port instead of the Well Know Port 69. 3737 3738 tftpblocksize - Block size to use for TFTP transfers; if not set, 3739 we use the TFTP server's default block size 3740 3741 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3742 seconds, minimum value is 1000 = 1 second). Defines 3743 when a packet is considered to be lost so it has to 3744 be retransmitted. The default is 5000 = 5 seconds. 3745 Lowering this value may make downloads succeed 3746 faster in networks with high packet loss rates or 3747 with unreliable TFTP servers. 3748 3749 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3750 unit, minimum value = 0). Defines how many timeouts 3751 can happen during a single file transfer before that 3752 transfer is aborted. The default is 10, and 0 means 3753 'no timeouts allowed'. Increasing this value may help 3754 downloads succeed with high packet loss rates, or with 3755 unreliable TFTP servers or client hardware. 3756 3757 vlan - When set to a value < 4095 the traffic over 3758 Ethernet is encapsulated/received over 802.1q 3759 VLAN tagged frames. 3760 3761 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3762 Unsigned value, in milliseconds. If not set, the period will 3763 be either the default (28000), or a value based on 3764 CONFIG_NET_RETRY_COUNT, if defined. This value has 3765 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3766 3767The following image location variables contain the location of images 3768used in booting. The "Image" column gives the role of the image and is 3769not an environment variable name. The other columns are environment 3770variable names. "File Name" gives the name of the file on a TFTP 3771server, "RAM Address" gives the location in RAM the image will be 3772loaded to, and "Flash Location" gives the image's address in NOR 3773flash or offset in NAND flash. 3774 3775*Note* - these variables don't have to be defined for all boards, some 3776boards currently use other variables for these purposes, and some 3777boards use these variables for other purposes. 3778 3779Image File Name RAM Address Flash Location 3780----- --------- ----------- -------------- 3781u-boot u-boot u-boot_addr_r u-boot_addr 3782Linux kernel bootfile kernel_addr_r kernel_addr 3783device tree blob fdtfile fdt_addr_r fdt_addr 3784ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3785 3786The following environment variables may be used and automatically 3787updated by the network boot commands ("bootp" and "rarpboot"), 3788depending the information provided by your boot server: 3789 3790 bootfile - see above 3791 dnsip - IP address of your Domain Name Server 3792 dnsip2 - IP address of your secondary Domain Name Server 3793 gatewayip - IP address of the Gateway (Router) to use 3794 hostname - Target hostname 3795 ipaddr - see above 3796 netmask - Subnet Mask 3797 rootpath - Pathname of the root filesystem on the NFS server 3798 serverip - see above 3799 3800 3801There are two special Environment Variables: 3802 3803 serial# - contains hardware identification information such 3804 as type string and/or serial number 3805 ethaddr - Ethernet address 3806 3807These variables can be set only once (usually during manufacturing of 3808the board). U-Boot refuses to delete or overwrite these variables 3809once they have been set once. 3810 3811 3812Further special Environment Variables: 3813 3814 ver - Contains the U-Boot version string as printed 3815 with the "version" command. This variable is 3816 readonly (see CONFIG_VERSION_VARIABLE). 3817 3818 3819Please note that changes to some configuration parameters may take 3820only effect after the next boot (yes, that's just like Windoze :-). 3821 3822 3823Callback functions for environment variables: 3824--------------------------------------------- 3825 3826For some environment variables, the behavior of u-boot needs to change 3827when their values are changed. This functionality allows functions to 3828be associated with arbitrary variables. On creation, overwrite, or 3829deletion, the callback will provide the opportunity for some side 3830effect to happen or for the change to be rejected. 3831 3832The callbacks are named and associated with a function using the 3833U_BOOT_ENV_CALLBACK macro in your board or driver code. 3834 3835These callbacks are associated with variables in one of two ways. The 3836static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3837in the board configuration to a string that defines a list of 3838associations. The list must be in the following format: 3839 3840 entry = variable_name[:callback_name] 3841 list = entry[,list] 3842 3843If the callback name is not specified, then the callback is deleted. 3844Spaces are also allowed anywhere in the list. 3845 3846Callbacks can also be associated by defining the ".callbacks" variable 3847with the same list format above. Any association in ".callbacks" will 3848override any association in the static list. You can define 3849CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3850".callbacks" environment variable in the default or embedded environment. 3851 3852If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3853regular expression. This allows multiple variables to be connected to 3854the same callback without explicitly listing them all out. 3855 3856The signature of the callback functions is: 3857 3858 int callback(const char *name, const char *value, enum env_op op, int flags) 3859 3860* name - changed environment variable 3861* value - new value of the environment variable 3862* op - operation (create, overwrite, or delete) 3863* flags - attributes of the environment variable change, see flags H_* in 3864 include/search.h 3865 3866The return value is 0 if the variable change is accepted and 1 otherwise. 3867 3868Command Line Parsing: 3869===================== 3870 3871There are two different command line parsers available with U-Boot: 3872the old "simple" one, and the much more powerful "hush" shell: 3873 3874Old, simple command line parser: 3875-------------------------------- 3876 3877- supports environment variables (through setenv / saveenv commands) 3878- several commands on one line, separated by ';' 3879- variable substitution using "... ${name} ..." syntax 3880- special characters ('$', ';') can be escaped by prefixing with '\', 3881 for example: 3882 setenv bootcmd bootm \${address} 3883- You can also escape text by enclosing in single apostrophes, for example: 3884 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 3885 3886Hush shell: 3887----------- 3888 3889- similar to Bourne shell, with control structures like 3890 if...then...else...fi, for...do...done; while...do...done, 3891 until...do...done, ... 3892- supports environment ("global") variables (through setenv / saveenv 3893 commands) and local shell variables (through standard shell syntax 3894 "name=value"); only environment variables can be used with "run" 3895 command 3896 3897General rules: 3898-------------- 3899 3900(1) If a command line (or an environment variable executed by a "run" 3901 command) contains several commands separated by semicolon, and 3902 one of these commands fails, then the remaining commands will be 3903 executed anyway. 3904 3905(2) If you execute several variables with one call to run (i. e. 3906 calling run with a list of variables as arguments), any failing 3907 command will cause "run" to terminate, i. e. the remaining 3908 variables are not executed. 3909 3910Note for Redundant Ethernet Interfaces: 3911======================================= 3912 3913Some boards come with redundant Ethernet interfaces; U-Boot supports 3914such configurations and is capable of automatic selection of a 3915"working" interface when needed. MAC assignment works as follows: 3916 3917Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 3918MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 3919"eth1addr" (=>eth1), "eth2addr", ... 3920 3921If the network interface stores some valid MAC address (for instance 3922in SROM), this is used as default address if there is NO correspon- 3923ding setting in the environment; if the corresponding environment 3924variable is set, this overrides the settings in the card; that means: 3925 3926o If the SROM has a valid MAC address, and there is no address in the 3927 environment, the SROM's address is used. 3928 3929o If there is no valid address in the SROM, and a definition in the 3930 environment exists, then the value from the environment variable is 3931 used. 3932 3933o If both the SROM and the environment contain a MAC address, and 3934 both addresses are the same, this MAC address is used. 3935 3936o If both the SROM and the environment contain a MAC address, and the 3937 addresses differ, the value from the environment is used and a 3938 warning is printed. 3939 3940o If neither SROM nor the environment contain a MAC address, an error 3941 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 3942 a random, locally-assigned MAC is used. 3943 3944If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 3945will be programmed into hardware as part of the initialization process. This 3946may be skipped by setting the appropriate 'ethmacskip' environment variable. 3947The naming convention is as follows: 3948"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 3949 3950Image Formats: 3951============== 3952 3953U-Boot is capable of booting (and performing other auxiliary operations on) 3954images in two formats: 3955 3956New uImage format (FIT) 3957----------------------- 3958 3959Flexible and powerful format based on Flattened Image Tree -- FIT (similar 3960to Flattened Device Tree). It allows the use of images with multiple 3961components (several kernels, ramdisks, etc.), with contents protected by 3962SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 3963 3964 3965Old uImage format 3966----------------- 3967 3968Old image format is based on binary files which can be basically anything, 3969preceded by a special header; see the definitions in include/image.h for 3970details; basically, the header defines the following image properties: 3971 3972* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 3973 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 3974 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 3975 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 3976 INTEGRITY). 3977* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 3978 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 3979 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 3980* Compression Type (uncompressed, gzip, bzip2) 3981* Load Address 3982* Entry Point 3983* Image Name 3984* Image Timestamp 3985 3986The header is marked by a special Magic Number, and both the header 3987and the data portions of the image are secured against corruption by 3988CRC32 checksums. 3989 3990 3991Linux Support: 3992============== 3993 3994Although U-Boot should support any OS or standalone application 3995easily, the main focus has always been on Linux during the design of 3996U-Boot. 3997 3998U-Boot includes many features that so far have been part of some 3999special "boot loader" code within the Linux kernel. Also, any 4000"initrd" images to be used are no longer part of one big Linux image; 4001instead, kernel and "initrd" are separate images. This implementation 4002serves several purposes: 4003 4004- the same features can be used for other OS or standalone 4005 applications (for instance: using compressed images to reduce the 4006 Flash memory footprint) 4007 4008- it becomes much easier to port new Linux kernel versions because 4009 lots of low-level, hardware dependent stuff are done by U-Boot 4010 4011- the same Linux kernel image can now be used with different "initrd" 4012 images; of course this also means that different kernel images can 4013 be run with the same "initrd". This makes testing easier (you don't 4014 have to build a new "zImage.initrd" Linux image when you just 4015 change a file in your "initrd"). Also, a field-upgrade of the 4016 software is easier now. 4017 4018 4019Linux HOWTO: 4020============ 4021 4022Porting Linux to U-Boot based systems: 4023--------------------------------------- 4024 4025U-Boot cannot save you from doing all the necessary modifications to 4026configure the Linux device drivers for use with your target hardware 4027(no, we don't intend to provide a full virtual machine interface to 4028Linux :-). 4029 4030But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 4031 4032Just make sure your machine specific header file (for instance 4033include/asm-ppc/tqm8xx.h) includes the same definition of the Board 4034Information structure as we define in include/asm-<arch>/u-boot.h, 4035and make sure that your definition of IMAP_ADDR uses the same value 4036as your U-Boot configuration in CONFIG_SYS_IMMR. 4037 4038Note that U-Boot now has a driver model, a unified model for drivers. 4039If you are adding a new driver, plumb it into driver model. If there 4040is no uclass available, you are encouraged to create one. See 4041doc/driver-model. 4042 4043 4044Configuring the Linux kernel: 4045----------------------------- 4046 4047No specific requirements for U-Boot. Make sure you have some root 4048device (initial ramdisk, NFS) for your target system. 4049 4050 4051Building a Linux Image: 4052----------------------- 4053 4054With U-Boot, "normal" build targets like "zImage" or "bzImage" are 4055not used. If you use recent kernel source, a new build target 4056"uImage" will exist which automatically builds an image usable by 4057U-Boot. Most older kernels also have support for a "pImage" target, 4058which was introduced for our predecessor project PPCBoot and uses a 4059100% compatible format. 4060 4061Example: 4062 4063 make TQM850L_defconfig 4064 make oldconfig 4065 make dep 4066 make uImage 4067 4068The "uImage" build target uses a special tool (in 'tools/mkimage') to 4069encapsulate a compressed Linux kernel image with header information, 4070CRC32 checksum etc. for use with U-Boot. This is what we are doing: 4071 4072* build a standard "vmlinux" kernel image (in ELF binary format): 4073 4074* convert the kernel into a raw binary image: 4075 4076 ${CROSS_COMPILE}-objcopy -O binary \ 4077 -R .note -R .comment \ 4078 -S vmlinux linux.bin 4079 4080* compress the binary image: 4081 4082 gzip -9 linux.bin 4083 4084* package compressed binary image for U-Boot: 4085 4086 mkimage -A ppc -O linux -T kernel -C gzip \ 4087 -a 0 -e 0 -n "Linux Kernel Image" \ 4088 -d linux.bin.gz uImage 4089 4090 4091The "mkimage" tool can also be used to create ramdisk images for use 4092with U-Boot, either separated from the Linux kernel image, or 4093combined into one file. "mkimage" encapsulates the images with a 64 4094byte header containing information about target architecture, 4095operating system, image type, compression method, entry points, time 4096stamp, CRC32 checksums, etc. 4097 4098"mkimage" can be called in two ways: to verify existing images and 4099print the header information, or to build new images. 4100 4101In the first form (with "-l" option) mkimage lists the information 4102contained in the header of an existing U-Boot image; this includes 4103checksum verification: 4104 4105 tools/mkimage -l image 4106 -l ==> list image header information 4107 4108The second form (with "-d" option) is used to build a U-Boot image 4109from a "data file" which is used as image payload: 4110 4111 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 4112 -n name -d data_file image 4113 -A ==> set architecture to 'arch' 4114 -O ==> set operating system to 'os' 4115 -T ==> set image type to 'type' 4116 -C ==> set compression type 'comp' 4117 -a ==> set load address to 'addr' (hex) 4118 -e ==> set entry point to 'ep' (hex) 4119 -n ==> set image name to 'name' 4120 -d ==> use image data from 'datafile' 4121 4122Right now, all Linux kernels for PowerPC systems use the same load 4123address (0x00000000), but the entry point address depends on the 4124kernel version: 4125 4126- 2.2.x kernels have the entry point at 0x0000000C, 4127- 2.3.x and later kernels have the entry point at 0x00000000. 4128 4129So a typical call to build a U-Boot image would read: 4130 4131 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4132 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 4133 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 4134 > examples/uImage.TQM850L 4135 Image Name: 2.4.4 kernel for TQM850L 4136 Created: Wed Jul 19 02:34:59 2000 4137 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4138 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4139 Load Address: 0x00000000 4140 Entry Point: 0x00000000 4141 4142To verify the contents of the image (or check for corruption): 4143 4144 -> tools/mkimage -l examples/uImage.TQM850L 4145 Image Name: 2.4.4 kernel for TQM850L 4146 Created: Wed Jul 19 02:34:59 2000 4147 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4148 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4149 Load Address: 0x00000000 4150 Entry Point: 0x00000000 4151 4152NOTE: for embedded systems where boot time is critical you can trade 4153speed for memory and install an UNCOMPRESSED image instead: this 4154needs more space in Flash, but boots much faster since it does not 4155need to be uncompressed: 4156 4157 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 4158 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4159 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 4160 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 4161 > examples/uImage.TQM850L-uncompressed 4162 Image Name: 2.4.4 kernel for TQM850L 4163 Created: Wed Jul 19 02:34:59 2000 4164 Image Type: PowerPC Linux Kernel Image (uncompressed) 4165 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 4166 Load Address: 0x00000000 4167 Entry Point: 0x00000000 4168 4169 4170Similar you can build U-Boot images from a 'ramdisk.image.gz' file 4171when your kernel is intended to use an initial ramdisk: 4172 4173 -> tools/mkimage -n 'Simple Ramdisk Image' \ 4174 > -A ppc -O linux -T ramdisk -C gzip \ 4175 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 4176 Image Name: Simple Ramdisk Image 4177 Created: Wed Jan 12 14:01:50 2000 4178 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4179 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 4180 Load Address: 0x00000000 4181 Entry Point: 0x00000000 4182 4183The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i" 4184option performs the converse operation of the mkimage's second form (the "-d" 4185option). Given an image built by mkimage, the dumpimage extracts a "data file" 4186from the image: 4187 4188 tools/dumpimage -i image -T type -p position data_file 4189 -i ==> extract from the 'image' a specific 'data_file' 4190 -T ==> set image type to 'type' 4191 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image' 4192 4193 4194Installing a Linux Image: 4195------------------------- 4196 4197To downloading a U-Boot image over the serial (console) interface, 4198you must convert the image to S-Record format: 4199 4200 objcopy -I binary -O srec examples/image examples/image.srec 4201 4202The 'objcopy' does not understand the information in the U-Boot 4203image header, so the resulting S-Record file will be relative to 4204address 0x00000000. To load it to a given address, you need to 4205specify the target address as 'offset' parameter with the 'loads' 4206command. 4207 4208Example: install the image to address 0x40100000 (which on the 4209TQM8xxL is in the first Flash bank): 4210 4211 => erase 40100000 401FFFFF 4212 4213 .......... done 4214 Erased 8 sectors 4215 4216 => loads 40100000 4217 ## Ready for S-Record download ... 4218 ~>examples/image.srec 4219 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 4220 ... 4221 15989 15990 15991 15992 4222 [file transfer complete] 4223 [connected] 4224 ## Start Addr = 0x00000000 4225 4226 4227You can check the success of the download using the 'iminfo' command; 4228this includes a checksum verification so you can be sure no data 4229corruption happened: 4230 4231 => imi 40100000 4232 4233 ## Checking Image at 40100000 ... 4234 Image Name: 2.2.13 for initrd on TQM850L 4235 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4236 Data Size: 335725 Bytes = 327 kB = 0 MB 4237 Load Address: 00000000 4238 Entry Point: 0000000c 4239 Verifying Checksum ... OK 4240 4241 4242Boot Linux: 4243----------- 4244 4245The "bootm" command is used to boot an application that is stored in 4246memory (RAM or Flash). In case of a Linux kernel image, the contents 4247of the "bootargs" environment variable is passed to the kernel as 4248parameters. You can check and modify this variable using the 4249"printenv" and "setenv" commands: 4250 4251 4252 => printenv bootargs 4253 bootargs=root=/dev/ram 4254 4255 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4256 4257 => printenv bootargs 4258 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4259 4260 => bootm 40020000 4261 ## Booting Linux kernel at 40020000 ... 4262 Image Name: 2.2.13 for NFS on TQM850L 4263 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4264 Data Size: 381681 Bytes = 372 kB = 0 MB 4265 Load Address: 00000000 4266 Entry Point: 0000000c 4267 Verifying Checksum ... OK 4268 Uncompressing Kernel Image ... OK 4269 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 4270 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4271 time_init: decrementer frequency = 187500000/60 4272 Calibrating delay loop... 49.77 BogoMIPS 4273 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 4274 ... 4275 4276If you want to boot a Linux kernel with initial RAM disk, you pass 4277the memory addresses of both the kernel and the initrd image (PPBCOOT 4278format!) to the "bootm" command: 4279 4280 => imi 40100000 40200000 4281 4282 ## Checking Image at 40100000 ... 4283 Image Name: 2.2.13 for initrd on TQM850L 4284 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4285 Data Size: 335725 Bytes = 327 kB = 0 MB 4286 Load Address: 00000000 4287 Entry Point: 0000000c 4288 Verifying Checksum ... OK 4289 4290 ## Checking Image at 40200000 ... 4291 Image Name: Simple Ramdisk Image 4292 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4293 Data Size: 566530 Bytes = 553 kB = 0 MB 4294 Load Address: 00000000 4295 Entry Point: 00000000 4296 Verifying Checksum ... OK 4297 4298 => bootm 40100000 40200000 4299 ## Booting Linux kernel at 40100000 ... 4300 Image Name: 2.2.13 for initrd on TQM850L 4301 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4302 Data Size: 335725 Bytes = 327 kB = 0 MB 4303 Load Address: 00000000 4304 Entry Point: 0000000c 4305 Verifying Checksum ... OK 4306 Uncompressing Kernel Image ... OK 4307 ## Loading RAMDisk Image at 40200000 ... 4308 Image Name: Simple Ramdisk Image 4309 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4310 Data Size: 566530 Bytes = 553 kB = 0 MB 4311 Load Address: 00000000 4312 Entry Point: 00000000 4313 Verifying Checksum ... OK 4314 Loading Ramdisk ... OK 4315 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 4316 Boot arguments: root=/dev/ram 4317 time_init: decrementer frequency = 187500000/60 4318 Calibrating delay loop... 49.77 BogoMIPS 4319 ... 4320 RAMDISK: Compressed image found at block 0 4321 VFS: Mounted root (ext2 filesystem). 4322 4323 bash# 4324 4325Boot Linux and pass a flat device tree: 4326----------- 4327 4328First, U-Boot must be compiled with the appropriate defines. See the section 4329titled "Linux Kernel Interface" above for a more in depth explanation. The 4330following is an example of how to start a kernel and pass an updated 4331flat device tree: 4332 4333=> print oftaddr 4334oftaddr=0x300000 4335=> print oft 4336oft=oftrees/mpc8540ads.dtb 4337=> tftp $oftaddr $oft 4338Speed: 1000, full duplex 4339Using TSEC0 device 4340TFTP from server 192.168.1.1; our IP address is 192.168.1.101 4341Filename 'oftrees/mpc8540ads.dtb'. 4342Load address: 0x300000 4343Loading: # 4344done 4345Bytes transferred = 4106 (100a hex) 4346=> tftp $loadaddr $bootfile 4347Speed: 1000, full duplex 4348Using TSEC0 device 4349TFTP from server 192.168.1.1; our IP address is 192.168.1.2 4350Filename 'uImage'. 4351Load address: 0x200000 4352Loading:############ 4353done 4354Bytes transferred = 1029407 (fb51f hex) 4355=> print loadaddr 4356loadaddr=200000 4357=> print oftaddr 4358oftaddr=0x300000 4359=> bootm $loadaddr - $oftaddr 4360## Booting image at 00200000 ... 4361 Image Name: Linux-2.6.17-dirty 4362 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4363 Data Size: 1029343 Bytes = 1005.2 kB 4364 Load Address: 00000000 4365 Entry Point: 00000000 4366 Verifying Checksum ... OK 4367 Uncompressing Kernel Image ... OK 4368Booting using flat device tree at 0x300000 4369Using MPC85xx ADS machine description 4370Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 4371[snip] 4372 4373 4374More About U-Boot Image Types: 4375------------------------------ 4376 4377U-Boot supports the following image types: 4378 4379 "Standalone Programs" are directly runnable in the environment 4380 provided by U-Boot; it is expected that (if they behave 4381 well) you can continue to work in U-Boot after return from 4382 the Standalone Program. 4383 "OS Kernel Images" are usually images of some Embedded OS which 4384 will take over control completely. Usually these programs 4385 will install their own set of exception handlers, device 4386 drivers, set up the MMU, etc. - this means, that you cannot 4387 expect to re-enter U-Boot except by resetting the CPU. 4388 "RAMDisk Images" are more or less just data blocks, and their 4389 parameters (address, size) are passed to an OS kernel that is 4390 being started. 4391 "Multi-File Images" contain several images, typically an OS 4392 (Linux) kernel image and one or more data images like 4393 RAMDisks. This construct is useful for instance when you want 4394 to boot over the network using BOOTP etc., where the boot 4395 server provides just a single image file, but you want to get 4396 for instance an OS kernel and a RAMDisk image. 4397 4398 "Multi-File Images" start with a list of image sizes, each 4399 image size (in bytes) specified by an "uint32_t" in network 4400 byte order. This list is terminated by an "(uint32_t)0". 4401 Immediately after the terminating 0 follow the images, one by 4402 one, all aligned on "uint32_t" boundaries (size rounded up to 4403 a multiple of 4 bytes). 4404 4405 "Firmware Images" are binary images containing firmware (like 4406 U-Boot or FPGA images) which usually will be programmed to 4407 flash memory. 4408 4409 "Script files" are command sequences that will be executed by 4410 U-Boot's command interpreter; this feature is especially 4411 useful when you configure U-Boot to use a real shell (hush) 4412 as command interpreter. 4413 4414Booting the Linux zImage: 4415------------------------- 4416 4417On some platforms, it's possible to boot Linux zImage. This is done 4418using the "bootz" command. The syntax of "bootz" command is the same 4419as the syntax of "bootm" command. 4420 4421Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4422kernel with raw initrd images. The syntax is slightly different, the 4423address of the initrd must be augmented by it's size, in the following 4424format: "<initrd addres>:<initrd size>". 4425 4426 4427Standalone HOWTO: 4428================= 4429 4430One of the features of U-Boot is that you can dynamically load and 4431run "standalone" applications, which can use some resources of 4432U-Boot like console I/O functions or interrupt services. 4433 4434Two simple examples are included with the sources: 4435 4436"Hello World" Demo: 4437------------------- 4438 4439'examples/hello_world.c' contains a small "Hello World" Demo 4440application; it is automatically compiled when you build U-Boot. 4441It's configured to run at address 0x00040004, so you can play with it 4442like that: 4443 4444 => loads 4445 ## Ready for S-Record download ... 4446 ~>examples/hello_world.srec 4447 1 2 3 4 5 6 7 8 9 10 11 ... 4448 [file transfer complete] 4449 [connected] 4450 ## Start Addr = 0x00040004 4451 4452 => go 40004 Hello World! This is a test. 4453 ## Starting application at 0x00040004 ... 4454 Hello World 4455 argc = 7 4456 argv[0] = "40004" 4457 argv[1] = "Hello" 4458 argv[2] = "World!" 4459 argv[3] = "This" 4460 argv[4] = "is" 4461 argv[5] = "a" 4462 argv[6] = "test." 4463 argv[7] = "<NULL>" 4464 Hit any key to exit ... 4465 4466 ## Application terminated, rc = 0x0 4467 4468Another example, which demonstrates how to register a CPM interrupt 4469handler with the U-Boot code, can be found in 'examples/timer.c'. 4470Here, a CPM timer is set up to generate an interrupt every second. 4471The interrupt service routine is trivial, just printing a '.' 4472character, but this is just a demo program. The application can be 4473controlled by the following keys: 4474 4475 ? - print current values og the CPM Timer registers 4476 b - enable interrupts and start timer 4477 e - stop timer and disable interrupts 4478 q - quit application 4479 4480 => loads 4481 ## Ready for S-Record download ... 4482 ~>examples/timer.srec 4483 1 2 3 4 5 6 7 8 9 10 11 ... 4484 [file transfer complete] 4485 [connected] 4486 ## Start Addr = 0x00040004 4487 4488 => go 40004 4489 ## Starting application at 0x00040004 ... 4490 TIMERS=0xfff00980 4491 Using timer 1 4492 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4493 4494Hit 'b': 4495 [q, b, e, ?] Set interval 1000000 us 4496 Enabling timer 4497Hit '?': 4498 [q, b, e, ?] ........ 4499 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4500Hit '?': 4501 [q, b, e, ?] . 4502 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4503Hit '?': 4504 [q, b, e, ?] . 4505 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4506Hit '?': 4507 [q, b, e, ?] . 4508 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4509Hit 'e': 4510 [q, b, e, ?] ...Stopping timer 4511Hit 'q': 4512 [q, b, e, ?] ## Application terminated, rc = 0x0 4513 4514 4515Minicom warning: 4516================ 4517 4518Over time, many people have reported problems when trying to use the 4519"minicom" terminal emulation program for serial download. I (wd) 4520consider minicom to be broken, and recommend not to use it. Under 4521Unix, I recommend to use C-Kermit for general purpose use (and 4522especially for kermit binary protocol download ("loadb" command), and 4523use "cu" for S-Record download ("loads" command). See 4524http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4525for help with kermit. 4526 4527 4528Nevertheless, if you absolutely want to use it try adding this 4529configuration to your "File transfer protocols" section: 4530 4531 Name Program Name U/D FullScr IO-Red. Multi 4532 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4533 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4534 4535 4536NetBSD Notes: 4537============= 4538 4539Starting at version 0.9.2, U-Boot supports NetBSD both as host 4540(build U-Boot) and target system (boots NetBSD/mpc8xx). 4541 4542Building requires a cross environment; it is known to work on 4543NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4544need gmake since the Makefiles are not compatible with BSD make). 4545Note that the cross-powerpc package does not install include files; 4546attempting to build U-Boot will fail because <machine/ansi.h> is 4547missing. This file has to be installed and patched manually: 4548 4549 # cd /usr/pkg/cross/powerpc-netbsd/include 4550 # mkdir powerpc 4551 # ln -s powerpc machine 4552 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4553 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4554 4555Native builds *don't* work due to incompatibilities between native 4556and U-Boot include files. 4557 4558Booting assumes that (the first part of) the image booted is a 4559stage-2 loader which in turn loads and then invokes the kernel 4560proper. Loader sources will eventually appear in the NetBSD source 4561tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4562meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4563 4564 4565Implementation Internals: 4566========================= 4567 4568The following is not intended to be a complete description of every 4569implementation detail. However, it should help to understand the 4570inner workings of U-Boot and make it easier to port it to custom 4571hardware. 4572 4573 4574Initial Stack, Global Data: 4575--------------------------- 4576 4577The implementation of U-Boot is complicated by the fact that U-Boot 4578starts running out of ROM (flash memory), usually without access to 4579system RAM (because the memory controller is not initialized yet). 4580This means that we don't have writable Data or BSS segments, and BSS 4581is not initialized as zero. To be able to get a C environment working 4582at all, we have to allocate at least a minimal stack. Implementation 4583options for this are defined and restricted by the CPU used: Some CPU 4584models provide on-chip memory (like the IMMR area on MPC8xx and 4585MPC826x processors), on others (parts of) the data cache can be 4586locked as (mis-) used as memory, etc. 4587 4588 Chris Hallinan posted a good summary of these issues to the 4589 U-Boot mailing list: 4590 4591 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4592 From: "Chris Hallinan" <clh@net1plus.com> 4593 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4594 ... 4595 4596 Correct me if I'm wrong, folks, but the way I understand it 4597 is this: Using DCACHE as initial RAM for Stack, etc, does not 4598 require any physical RAM backing up the cache. The cleverness 4599 is that the cache is being used as a temporary supply of 4600 necessary storage before the SDRAM controller is setup. It's 4601 beyond the scope of this list to explain the details, but you 4602 can see how this works by studying the cache architecture and 4603 operation in the architecture and processor-specific manuals. 4604 4605 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4606 is another option for the system designer to use as an 4607 initial stack/RAM area prior to SDRAM being available. Either 4608 option should work for you. Using CS 4 should be fine if your 4609 board designers haven't used it for something that would 4610 cause you grief during the initial boot! It is frequently not 4611 used. 4612 4613 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4614 with your processor/board/system design. The default value 4615 you will find in any recent u-boot distribution in 4616 walnut.h should work for you. I'd set it to a value larger 4617 than your SDRAM module. If you have a 64MB SDRAM module, set 4618 it above 400_0000. Just make sure your board has no resources 4619 that are supposed to respond to that address! That code in 4620 start.S has been around a while and should work as is when 4621 you get the config right. 4622 4623 -Chris Hallinan 4624 DS4.COM, Inc. 4625 4626It is essential to remember this, since it has some impact on the C 4627code for the initialization procedures: 4628 4629* Initialized global data (data segment) is read-only. Do not attempt 4630 to write it. 4631 4632* Do not use any uninitialized global data (or implicitly initialized 4633 as zero data - BSS segment) at all - this is undefined, initiali- 4634 zation is performed later (when relocating to RAM). 4635 4636* Stack space is very limited. Avoid big data buffers or things like 4637 that. 4638 4639Having only the stack as writable memory limits means we cannot use 4640normal global data to share information between the code. But it 4641turned out that the implementation of U-Boot can be greatly 4642simplified by making a global data structure (gd_t) available to all 4643functions. We could pass a pointer to this data as argument to _all_ 4644functions, but this would bloat the code. Instead we use a feature of 4645the GCC compiler (Global Register Variables) to share the data: we 4646place a pointer (gd) to the global data into a register which we 4647reserve for this purpose. 4648 4649When choosing a register for such a purpose we are restricted by the 4650relevant (E)ABI specifications for the current architecture, and by 4651GCC's implementation. 4652 4653For PowerPC, the following registers have specific use: 4654 R1: stack pointer 4655 R2: reserved for system use 4656 R3-R4: parameter passing and return values 4657 R5-R10: parameter passing 4658 R13: small data area pointer 4659 R30: GOT pointer 4660 R31: frame pointer 4661 4662 (U-Boot also uses R12 as internal GOT pointer. r12 4663 is a volatile register so r12 needs to be reset when 4664 going back and forth between asm and C) 4665 4666 ==> U-Boot will use R2 to hold a pointer to the global data 4667 4668 Note: on PPC, we could use a static initializer (since the 4669 address of the global data structure is known at compile time), 4670 but it turned out that reserving a register results in somewhat 4671 smaller code - although the code savings are not that big (on 4672 average for all boards 752 bytes for the whole U-Boot image, 4673 624 text + 127 data). 4674 4675On ARM, the following registers are used: 4676 4677 R0: function argument word/integer result 4678 R1-R3: function argument word 4679 R9: platform specific 4680 R10: stack limit (used only if stack checking is enabled) 4681 R11: argument (frame) pointer 4682 R12: temporary workspace 4683 R13: stack pointer 4684 R14: link register 4685 R15: program counter 4686 4687 ==> U-Boot will use R9 to hold a pointer to the global data 4688 4689 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4690 4691On Nios II, the ABI is documented here: 4692 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4693 4694 ==> U-Boot will use gp to hold a pointer to the global data 4695 4696 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4697 to access small data sections, so gp is free. 4698 4699On NDS32, the following registers are used: 4700 4701 R0-R1: argument/return 4702 R2-R5: argument 4703 R15: temporary register for assembler 4704 R16: trampoline register 4705 R28: frame pointer (FP) 4706 R29: global pointer (GP) 4707 R30: link register (LP) 4708 R31: stack pointer (SP) 4709 PC: program counter (PC) 4710 4711 ==> U-Boot will use R10 to hold a pointer to the global data 4712 4713NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4714or current versions of GCC may "optimize" the code too much. 4715 4716On RISC-V, the following registers are used: 4717 4718 x0: hard-wired zero (zero) 4719 x1: return address (ra) 4720 x2: stack pointer (sp) 4721 x3: global pointer (gp) 4722 x4: thread pointer (tp) 4723 x5: link register (t0) 4724 x8: frame pointer (fp) 4725 x10-x11: arguments/return values (a0-1) 4726 x12-x17: arguments (a2-7) 4727 x28-31: temporaries (t3-6) 4728 pc: program counter (pc) 4729 4730 ==> U-Boot will use gp to hold a pointer to the global data 4731 4732Memory Management: 4733------------------ 4734 4735U-Boot runs in system state and uses physical addresses, i.e. the 4736MMU is not used either for address mapping nor for memory protection. 4737 4738The available memory is mapped to fixed addresses using the memory 4739controller. In this process, a contiguous block is formed for each 4740memory type (Flash, SDRAM, SRAM), even when it consists of several 4741physical memory banks. 4742 4743U-Boot is installed in the first 128 kB of the first Flash bank (on 4744TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4745booting and sizing and initializing DRAM, the code relocates itself 4746to the upper end of DRAM. Immediately below the U-Boot code some 4747memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4748configuration setting]. Below that, a structure with global Board 4749Info data is placed, followed by the stack (growing downward). 4750 4751Additionally, some exception handler code is copied to the low 8 kB 4752of DRAM (0x00000000 ... 0x00001FFF). 4753 4754So a typical memory configuration with 16 MB of DRAM could look like 4755this: 4756 4757 0x0000 0000 Exception Vector code 4758 : 4759 0x0000 1FFF 4760 0x0000 2000 Free for Application Use 4761 : 4762 : 4763 4764 : 4765 : 4766 0x00FB FF20 Monitor Stack (Growing downward) 4767 0x00FB FFAC Board Info Data and permanent copy of global data 4768 0x00FC 0000 Malloc Arena 4769 : 4770 0x00FD FFFF 4771 0x00FE 0000 RAM Copy of Monitor Code 4772 ... eventually: LCD or video framebuffer 4773 ... eventually: pRAM (Protected RAM - unchanged by reset) 4774 0x00FF FFFF [End of RAM] 4775 4776 4777System Initialization: 4778---------------------- 4779 4780In the reset configuration, U-Boot starts at the reset entry point 4781(on most PowerPC systems at address 0x00000100). Because of the reset 4782configuration for CS0# this is a mirror of the on board Flash memory. 4783To be able to re-map memory U-Boot then jumps to its link address. 4784To be able to implement the initialization code in C, a (small!) 4785initial stack is set up in the internal Dual Ported RAM (in case CPUs 4786which provide such a feature like), or in a locked part of the data 4787cache. After that, U-Boot initializes the CPU core, the caches and 4788the SIU. 4789 4790Next, all (potentially) available memory banks are mapped using a 4791preliminary mapping. For example, we put them on 512 MB boundaries 4792(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4793on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4794programmed for SDRAM access. Using the temporary configuration, a 4795simple memory test is run that determines the size of the SDRAM 4796banks. 4797 4798When there is more than one SDRAM bank, and the banks are of 4799different size, the largest is mapped first. For equal size, the first 4800bank (CS2#) is mapped first. The first mapping is always for address 48010x00000000, with any additional banks following immediately to create 4802contiguous memory starting from 0. 4803 4804Then, the monitor installs itself at the upper end of the SDRAM area 4805and allocates memory for use by malloc() and for the global Board 4806Info data; also, the exception vector code is copied to the low RAM 4807pages, and the final stack is set up. 4808 4809Only after this relocation will you have a "normal" C environment; 4810until that you are restricted in several ways, mostly because you are 4811running from ROM, and because the code will have to be relocated to a 4812new address in RAM. 4813 4814 4815U-Boot Porting Guide: 4816---------------------- 4817 4818[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4819list, October 2002] 4820 4821 4822int main(int argc, char *argv[]) 4823{ 4824 sighandler_t no_more_time; 4825 4826 signal(SIGALRM, no_more_time); 4827 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4828 4829 if (available_money > available_manpower) { 4830 Pay consultant to port U-Boot; 4831 return 0; 4832 } 4833 4834 Download latest U-Boot source; 4835 4836 Subscribe to u-boot mailing list; 4837 4838 if (clueless) 4839 email("Hi, I am new to U-Boot, how do I get started?"); 4840 4841 while (learning) { 4842 Read the README file in the top level directory; 4843 Read http://www.denx.de/twiki/bin/view/DULG/Manual; 4844 Read applicable doc/*.README; 4845 Read the source, Luke; 4846 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4847 } 4848 4849 if (available_money > toLocalCurrency ($2500)) 4850 Buy a BDI3000; 4851 else 4852 Add a lot of aggravation and time; 4853 4854 if (a similar board exists) { /* hopefully... */ 4855 cp -a board/<similar> board/<myboard> 4856 cp include/configs/<similar>.h include/configs/<myboard>.h 4857 } else { 4858 Create your own board support subdirectory; 4859 Create your own board include/configs/<myboard>.h file; 4860 } 4861 Edit new board/<myboard> files 4862 Edit new include/configs/<myboard>.h 4863 4864 while (!accepted) { 4865 while (!running) { 4866 do { 4867 Add / modify source code; 4868 } until (compiles); 4869 Debug; 4870 if (clueless) 4871 email("Hi, I am having problems..."); 4872 } 4873 Send patch file to the U-Boot email list; 4874 if (reasonable critiques) 4875 Incorporate improvements from email list code review; 4876 else 4877 Defend code as written; 4878 } 4879 4880 return 0; 4881} 4882 4883void no_more_time (int sig) 4884{ 4885 hire_a_guru(); 4886} 4887 4888 4889Coding Standards: 4890----------------- 4891 4892All contributions to U-Boot should conform to the Linux kernel 4893coding style; see the kernel coding style guide at 4894https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4895script "scripts/Lindent" in your Linux kernel source directory. 4896 4897Source files originating from a different project (for example the 4898MTD subsystem) are generally exempt from these guidelines and are not 4899reformatted to ease subsequent migration to newer versions of those 4900sources. 4901 4902Please note that U-Boot is implemented in C (and to some small parts in 4903Assembler); no C++ is used, so please do not use C++ style comments (//) 4904in your code. 4905 4906Please also stick to the following formatting rules: 4907- remove any trailing white space 4908- use TAB characters for indentation and vertical alignment, not spaces 4909- make sure NOT to use DOS '\r\n' line feeds 4910- do not add more than 2 consecutive empty lines to source files 4911- do not add trailing empty lines to source files 4912 4913Submissions which do not conform to the standards may be returned 4914with a request to reformat the changes. 4915 4916 4917Submitting Patches: 4918------------------- 4919 4920Since the number of patches for U-Boot is growing, we need to 4921establish some rules. Submissions which do not conform to these rules 4922may be rejected, even when they contain important and valuable stuff. 4923 4924Please see http://www.denx.de/wiki/U-Boot/Patches for details. 4925 4926Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 4927see https://lists.denx.de/listinfo/u-boot 4928 4929When you send a patch, please include the following information with 4930it: 4931 4932* For bug fixes: a description of the bug and how your patch fixes 4933 this bug. Please try to include a way of demonstrating that the 4934 patch actually fixes something. 4935 4936* For new features: a description of the feature and your 4937 implementation. 4938 4939* A CHANGELOG entry as plaintext (separate from the patch) 4940 4941* For major contributions, add a MAINTAINERS file with your 4942 information and associated file and directory references. 4943 4944* When you add support for a new board, don't forget to add a 4945 maintainer e-mail address to the boards.cfg file, too. 4946 4947* If your patch adds new configuration options, don't forget to 4948 document these in the README file. 4949 4950* The patch itself. If you are using git (which is *strongly* 4951 recommended) you can easily generate the patch using the 4952 "git format-patch". If you then use "git send-email" to send it to 4953 the U-Boot mailing list, you will avoid most of the common problems 4954 with some other mail clients. 4955 4956 If you cannot use git, use "diff -purN OLD NEW". If your version of 4957 diff does not support these options, then get the latest version of 4958 GNU diff. 4959 4960 The current directory when running this command shall be the parent 4961 directory of the U-Boot source tree (i. e. please make sure that 4962 your patch includes sufficient directory information for the 4963 affected files). 4964 4965 We prefer patches as plain text. MIME attachments are discouraged, 4966 and compressed attachments must not be used. 4967 4968* If one logical set of modifications affects or creates several 4969 files, all these changes shall be submitted in a SINGLE patch file. 4970 4971* Changesets that contain different, unrelated modifications shall be 4972 submitted as SEPARATE patches, one patch per changeset. 4973 4974 4975Notes: 4976 4977* Before sending the patch, run the buildman script on your patched 4978 source tree and make sure that no errors or warnings are reported 4979 for any of the boards. 4980 4981* Keep your modifications to the necessary minimum: A patch 4982 containing several unrelated changes or arbitrary reformats will be 4983 returned with a request to re-formatting / split it. 4984 4985* If you modify existing code, make sure that your new code does not 4986 add to the memory footprint of the code ;-) Small is beautiful! 4987 When adding new features, these should compile conditionally only 4988 (using #ifdef), and the resulting code with the new feature 4989 disabled must not need more memory than the old code without your 4990 modification. 4991 4992* Remember that there is a size limit of 100 kB per message on the 4993 u-boot mailing list. Bigger patches will be moderated. If they are 4994 reasonable and not too big, they will be acknowledged. But patches 4995 bigger than the size limit should be avoided. 4996