1# SPDX-License-Identifier: GPL-2.0+ 2# 3# (C) Copyright 2000 - 2013 4# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 5 6Summary: 7======== 8 9This directory contains the source code for U-Boot, a boot loader for 10Embedded boards based on PowerPC, ARM, MIPS and several other 11processors, which can be installed in a boot ROM and used to 12initialize and test the hardware or to download and run application 13code. 14 15The development of U-Boot is closely related to Linux: some parts of 16the source code originate in the Linux source tree, we have some 17header files in common, and special provision has been made to 18support booting of Linux images. 19 20Some attention has been paid to make this software easily 21configurable and extendable. For instance, all monitor commands are 22implemented with the same call interface, so that it's very easy to 23add new commands. Also, instead of permanently adding rarely used 24code (for instance hardware test utilities) to the monitor, you can 25load and run it dynamically. 26 27 28Status: 29======= 30 31In general, all boards for which a configuration option exists in the 32Makefile have been tested to some extent and can be considered 33"working". In fact, many of them are used in production systems. 34 35In case of problems see the CHANGELOG file to find out who contributed 36the specific port. In addition, there are various MAINTAINERS files 37scattered throughout the U-Boot source identifying the people or 38companies responsible for various boards and subsystems. 39 40Note: As of August, 2010, there is no longer a CHANGELOG file in the 41actual U-Boot source tree; however, it can be created dynamically 42from the Git log using: 43 44 make CHANGELOG 45 46 47Where to get help: 48================== 49 50In case you have questions about, problems with or contributions for 51U-Boot, you should send a message to the U-Boot mailing list at 52<u-boot@lists.denx.de>. There is also an archive of previous traffic 53on the mailing list - please search the archive before asking FAQ's. 54Please see http://lists.denx.de/pipermail/u-boot and 55http://dir.gmane.org/gmane.comp.boot-loaders.u-boot 56 57 58Where to get source code: 59========================= 60 61The U-Boot source code is maintained in the Git repository at 62git://www.denx.de/git/u-boot.git ; you can browse it online at 63http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary 64 65The "snapshot" links on this page allow you to download tarballs of 66any version you might be interested in. Official releases are also 67available for FTP download from the ftp://ftp.denx.de/pub/u-boot/ 68directory. 69 70Pre-built (and tested) images are available from 71ftp://ftp.denx.de/pub/u-boot/images/ 72 73 74Where we come from: 75=================== 76 77- start from 8xxrom sources 78- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 79- clean up code 80- make it easier to add custom boards 81- make it possible to add other [PowerPC] CPUs 82- extend functions, especially: 83 * Provide extended interface to Linux boot loader 84 * S-Record download 85 * network boot 86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot 87- create ARMBoot project (http://sourceforge.net/projects/armboot) 88- add other CPU families (starting with ARM) 89- create U-Boot project (http://sourceforge.net/projects/u-boot) 90- current project page: see http://www.denx.de/wiki/U-Boot 91 92 93Names and Spelling: 94=================== 95 96The "official" name of this project is "Das U-Boot". The spelling 97"U-Boot" shall be used in all written text (documentation, comments 98in source files etc.). Example: 99 100 This is the README file for the U-Boot project. 101 102File names etc. shall be based on the string "u-boot". Examples: 103 104 include/asm-ppc/u-boot.h 105 106 #include <asm/u-boot.h> 107 108Variable names, preprocessor constants etc. shall be either based on 109the string "u_boot" or on "U_BOOT". Example: 110 111 U_BOOT_VERSION u_boot_logo 112 IH_OS_U_BOOT u_boot_hush_start 113 114 115Versioning: 116=========== 117 118Starting with the release in October 2008, the names of the releases 119were changed from numerical release numbers without deeper meaning 120into a time stamp based numbering. Regular releases are identified by 121names consisting of the calendar year and month of the release date. 122Additional fields (if present) indicate release candidates or bug fix 123releases in "stable" maintenance trees. 124 125Examples: 126 U-Boot v2009.11 - Release November 2009 127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree 128 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release 129 130 131Directory Hierarchy: 132==================== 133 134/arch Architecture specific files 135 /arc Files generic to ARC architecture 136 /arm Files generic to ARM architecture 137 /m68k Files generic to m68k architecture 138 /microblaze Files generic to microblaze architecture 139 /mips Files generic to MIPS architecture 140 /nds32 Files generic to NDS32 architecture 141 /nios2 Files generic to Altera NIOS2 architecture 142 /openrisc Files generic to OpenRISC architecture 143 /powerpc Files generic to PowerPC architecture 144 /riscv Files generic to RISC-V architecture 145 /sandbox Files generic to HW-independent "sandbox" 146 /sh Files generic to SH architecture 147 /x86 Files generic to x86 architecture 148/api Machine/arch independent API for external apps 149/board Board dependent files 150/cmd U-Boot commands functions 151/common Misc architecture independent functions 152/configs Board default configuration files 153/disk Code for disk drive partition handling 154/doc Documentation (don't expect too much) 155/drivers Commonly used device drivers 156/dts Contains Makefile for building internal U-Boot fdt. 157/examples Example code for standalone applications, etc. 158/fs Filesystem code (cramfs, ext2, jffs2, etc.) 159/include Header Files 160/lib Library routines generic to all architectures 161/Licenses Various license files 162/net Networking code 163/post Power On Self Test 164/scripts Various build scripts and Makefiles 165/test Various unit test files 166/tools Tools to build S-Record or U-Boot images, etc. 167 168Software Configuration: 169======================= 170 171Configuration is usually done using C preprocessor defines; the 172rationale behind that is to avoid dead code whenever possible. 173 174There are two classes of configuration variables: 175 176* Configuration _OPTIONS_: 177 These are selectable by the user and have names beginning with 178 "CONFIG_". 179 180* Configuration _SETTINGS_: 181 These depend on the hardware etc. and should not be meddled with if 182 you don't know what you're doing; they have names beginning with 183 "CONFIG_SYS_". 184 185Previously, all configuration was done by hand, which involved creating 186symbolic links and editing configuration files manually. More recently, 187U-Boot has added the Kbuild infrastructure used by the Linux kernel, 188allowing you to use the "make menuconfig" command to configure your 189build. 190 191 192Selection of Processor Architecture and Board Type: 193--------------------------------------------------- 194 195For all supported boards there are ready-to-use default 196configurations available; just type "make <board_name>_defconfig". 197 198Example: For a TQM823L module type: 199 200 cd u-boot 201 make TQM823L_defconfig 202 203Note: If you're looking for the default configuration file for a board 204you're sure used to be there but is now missing, check the file 205doc/README.scrapyard for a list of no longer supported boards. 206 207Sandbox Environment: 208-------------------- 209 210U-Boot can be built natively to run on a Linux host using the 'sandbox' 211board. This allows feature development which is not board- or architecture- 212specific to be undertaken on a native platform. The sandbox is also used to 213run some of U-Boot's tests. 214 215See board/sandbox/README.sandbox for more details. 216 217 218Board Initialisation Flow: 219-------------------------- 220 221This is the intended start-up flow for boards. This should apply for both 222SPL and U-Boot proper (i.e. they both follow the same rules). 223 224Note: "SPL" stands for "Secondary Program Loader," which is explained in 225more detail later in this file. 226 227At present, SPL mostly uses a separate code path, but the function names 228and roles of each function are the same. Some boards or architectures 229may not conform to this. At least most ARM boards which use 230CONFIG_SPL_FRAMEWORK conform to this. 231 232Execution typically starts with an architecture-specific (and possibly 233CPU-specific) start.S file, such as: 234 235 - arch/arm/cpu/armv7/start.S 236 - arch/powerpc/cpu/mpc83xx/start.S 237 - arch/mips/cpu/start.S 238 239and so on. From there, three functions are called; the purpose and 240limitations of each of these functions are described below. 241 242lowlevel_init(): 243 - purpose: essential init to permit execution to reach board_init_f() 244 - no global_data or BSS 245 - there is no stack (ARMv7 may have one but it will soon be removed) 246 - must not set up SDRAM or use console 247 - must only do the bare minimum to allow execution to continue to 248 board_init_f() 249 - this is almost never needed 250 - return normally from this function 251 252board_init_f(): 253 - purpose: set up the machine ready for running board_init_r(): 254 i.e. SDRAM and serial UART 255 - global_data is available 256 - stack is in SRAM 257 - BSS is not available, so you cannot use global/static variables, 258 only stack variables and global_data 259 260 Non-SPL-specific notes: 261 - dram_init() is called to set up DRAM. If already done in SPL this 262 can do nothing 263 264 SPL-specific notes: 265 - you can override the entire board_init_f() function with your own 266 version as needed. 267 - preloader_console_init() can be called here in extremis 268 - should set up SDRAM, and anything needed to make the UART work 269 - these is no need to clear BSS, it will be done by crt0.S 270 - must return normally from this function (don't call board_init_r() 271 directly) 272 273Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at 274this point the stack and global_data are relocated to below 275CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of 276memory. 277 278board_init_r(): 279 - purpose: main execution, common code 280 - global_data is available 281 - SDRAM is available 282 - BSS is available, all static/global variables can be used 283 - execution eventually continues to main_loop() 284 285 Non-SPL-specific notes: 286 - U-Boot is relocated to the top of memory and is now running from 287 there. 288 289 SPL-specific notes: 290 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and 291 CONFIG_SPL_STACK_R_ADDR points into SDRAM 292 - preloader_console_init() can be called here - typically this is 293 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a 294 spl_board_init() function containing this call 295 - loads U-Boot or (in falcon mode) Linux 296 297 298 299Configuration Options: 300---------------------- 301 302Configuration depends on the combination of board and CPU type; all 303such information is kept in a configuration file 304"include/configs/<board_name>.h". 305 306Example: For a TQM823L module, all configuration settings are in 307"include/configs/TQM823L.h". 308 309 310Many of the options are named exactly as the corresponding Linux 311kernel configuration options. The intention is to make it easier to 312build a config tool - later. 313 314- ARM Platform Bus Type(CCI): 315 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which 316 provides full cache coherency between two clusters of multi-core 317 CPUs and I/O coherency for devices and I/O masters 318 319 CONFIG_SYS_FSL_HAS_CCI400 320 321 Defined For SoC that has cache coherent interconnect 322 CCN-400 323 324 CONFIG_SYS_FSL_HAS_CCN504 325 326 Defined for SoC that has cache coherent interconnect CCN-504 327 328The following options need to be configured: 329 330- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX. 331 332- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS. 333 334- 85xx CPU Options: 335 CONFIG_SYS_PPC64 336 337 Specifies that the core is a 64-bit PowerPC implementation (implements 338 the "64" category of the Power ISA). This is necessary for ePAPR 339 compliance, among other possible reasons. 340 341 CONFIG_SYS_FSL_TBCLK_DIV 342 343 Defines the core time base clock divider ratio compared to the 344 system clock. On most PQ3 devices this is 8, on newer QorIQ 345 devices it can be 16 or 32. The ratio varies from SoC to Soc. 346 347 CONFIG_SYS_FSL_PCIE_COMPAT 348 349 Defines the string to utilize when trying to match PCIe device 350 tree nodes for the given platform. 351 352 CONFIG_SYS_FSL_ERRATUM_A004510 353 354 Enables a workaround for erratum A004510. If set, 355 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and 356 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set. 357 358 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV 359 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional) 360 361 Defines one or two SoC revisions (low 8 bits of SVR) 362 for which the A004510 workaround should be applied. 363 364 The rest of SVR is either not relevant to the decision 365 of whether the erratum is present (e.g. p2040 versus 366 p2041) or is implied by the build target, which controls 367 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set. 368 369 See Freescale App Note 4493 for more information about 370 this erratum. 371 372 CONFIG_A003399_NOR_WORKAROUND 373 Enables a workaround for IFC erratum A003399. It is only 374 required during NOR boot. 375 376 CONFIG_A008044_WORKAROUND 377 Enables a workaround for T1040/T1042 erratum A008044. It is only 378 required during NAND boot and valid for Rev 1.0 SoC revision 379 380 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY 381 382 This is the value to write into CCSR offset 0x18600 383 according to the A004510 workaround. 384 385 CONFIG_SYS_FSL_DSP_DDR_ADDR 386 This value denotes start offset of DDR memory which is 387 connected exclusively to the DSP cores. 388 389 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR 390 This value denotes start offset of M2 memory 391 which is directly connected to the DSP core. 392 393 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR 394 This value denotes start offset of M3 memory which is directly 395 connected to the DSP core. 396 397 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT 398 This value denotes start offset of DSP CCSR space. 399 400 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK 401 Single Source Clock is clocking mode present in some of FSL SoC's. 402 In this mode, a single differential clock is used to supply 403 clocks to the sysclock, ddrclock and usbclock. 404 405 CONFIG_SYS_CPC_REINIT_F 406 This CONFIG is defined when the CPC is configured as SRAM at the 407 time of U-Boot entry and is required to be re-initialized. 408 409 CONFIG_DEEP_SLEEP 410 Indicates this SoC supports deep sleep feature. If deep sleep is 411 supported, core will start to execute uboot when wakes up. 412 413- Generic CPU options: 414 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN 415 416 Defines the endianess of the CPU. Implementation of those 417 values is arch specific. 418 419 CONFIG_SYS_FSL_DDR 420 Freescale DDR driver in use. This type of DDR controller is 421 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core 422 SoCs. 423 424 CONFIG_SYS_FSL_DDR_ADDR 425 Freescale DDR memory-mapped register base. 426 427 CONFIG_SYS_FSL_DDR_EMU 428 Specify emulator support for DDR. Some DDR features such as 429 deskew training are not available. 430 431 CONFIG_SYS_FSL_DDRC_GEN1 432 Freescale DDR1 controller. 433 434 CONFIG_SYS_FSL_DDRC_GEN2 435 Freescale DDR2 controller. 436 437 CONFIG_SYS_FSL_DDRC_GEN3 438 Freescale DDR3 controller. 439 440 CONFIG_SYS_FSL_DDRC_GEN4 441 Freescale DDR4 controller. 442 443 CONFIG_SYS_FSL_DDRC_ARM_GEN3 444 Freescale DDR3 controller for ARM-based SoCs. 445 446 CONFIG_SYS_FSL_DDR1 447 Board config to use DDR1. It can be enabled for SoCs with 448 Freescale DDR1 or DDR2 controllers, depending on the board 449 implemetation. 450 451 CONFIG_SYS_FSL_DDR2 452 Board config to use DDR2. It can be enabled for SoCs with 453 Freescale DDR2 or DDR3 controllers, depending on the board 454 implementation. 455 456 CONFIG_SYS_FSL_DDR3 457 Board config to use DDR3. It can be enabled for SoCs with 458 Freescale DDR3 or DDR3L controllers. 459 460 CONFIG_SYS_FSL_DDR3L 461 Board config to use DDR3L. It can be enabled for SoCs with 462 DDR3L controllers. 463 464 CONFIG_SYS_FSL_DDR4 465 Board config to use DDR4. It can be enabled for SoCs with 466 DDR4 controllers. 467 468 CONFIG_SYS_FSL_IFC_BE 469 Defines the IFC controller register space as Big Endian 470 471 CONFIG_SYS_FSL_IFC_LE 472 Defines the IFC controller register space as Little Endian 473 474 CONFIG_SYS_FSL_IFC_CLK_DIV 475 Defines divider of platform clock(clock input to IFC controller). 476 477 CONFIG_SYS_FSL_LBC_CLK_DIV 478 Defines divider of platform clock(clock input to eLBC controller). 479 480 CONFIG_SYS_FSL_PBL_PBI 481 It enables addition of RCW (Power on reset configuration) in built image. 482 Please refer doc/README.pblimage for more details 483 484 CONFIG_SYS_FSL_PBL_RCW 485 It adds PBI(pre-boot instructions) commands in u-boot build image. 486 PBI commands can be used to configure SoC before it starts the execution. 487 Please refer doc/README.pblimage for more details 488 489 CONFIG_SPL_FSL_PBL 490 It adds a target to create boot binary having SPL binary in PBI format 491 concatenated with u-boot binary. 492 493 CONFIG_SYS_FSL_DDR_BE 494 Defines the DDR controller register space as Big Endian 495 496 CONFIG_SYS_FSL_DDR_LE 497 Defines the DDR controller register space as Little Endian 498 499 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY 500 Physical address from the view of DDR controllers. It is the 501 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But 502 it could be different for ARM SoCs. 503 504 CONFIG_SYS_FSL_DDR_INTLV_256B 505 DDR controller interleaving on 256-byte. This is a special 506 interleaving mode, handled by Dickens for Freescale layerscape 507 SoCs with ARM core. 508 509 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS 510 Number of controllers used as main memory. 511 512 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS 513 Number of controllers used for other than main memory. 514 515 CONFIG_SYS_FSL_HAS_DP_DDR 516 Defines the SoC has DP-DDR used for DPAA. 517 518 CONFIG_SYS_FSL_SEC_BE 519 Defines the SEC controller register space as Big Endian 520 521 CONFIG_SYS_FSL_SEC_LE 522 Defines the SEC controller register space as Little Endian 523 524- MIPS CPU options: 525 CONFIG_SYS_INIT_SP_OFFSET 526 527 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack 528 pointer. This is needed for the temporary stack before 529 relocation. 530 531 CONFIG_XWAY_SWAP_BYTES 532 533 Enable compilation of tools/xway-swap-bytes needed for Lantiq 534 XWAY SoCs for booting from NOR flash. The U-Boot image needs to 535 be swapped if a flash programmer is used. 536 537- ARM options: 538 CONFIG_SYS_EXCEPTION_VECTORS_HIGH 539 540 Select high exception vectors of the ARM core, e.g., do not 541 clear the V bit of the c1 register of CP15. 542 543 COUNTER_FREQUENCY 544 Generic timer clock source frequency. 545 546 COUNTER_FREQUENCY_REAL 547 Generic timer clock source frequency if the real clock is 548 different from COUNTER_FREQUENCY, and can only be determined 549 at run time. 550 551- Tegra SoC options: 552 CONFIG_TEGRA_SUPPORT_NON_SECURE 553 554 Support executing U-Boot in non-secure (NS) mode. Certain 555 impossible actions will be skipped if the CPU is in NS mode, 556 such as ARM architectural timer initialization. 557 558- Linux Kernel Interface: 559 CONFIG_CLOCKS_IN_MHZ 560 561 U-Boot stores all clock information in Hz 562 internally. For binary compatibility with older Linux 563 kernels (which expect the clocks passed in the 564 bd_info data to be in MHz) the environment variable 565 "clocks_in_mhz" can be defined so that U-Boot 566 converts clock data to MHZ before passing it to the 567 Linux kernel. 568 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 569 "clocks_in_mhz=1" is automatically included in the 570 default environment. 571 572 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 573 574 When transferring memsize parameter to Linux, some versions 575 expect it to be in bytes, others in MB. 576 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 577 578 CONFIG_OF_LIBFDT 579 580 New kernel versions are expecting firmware settings to be 581 passed using flattened device trees (based on open firmware 582 concepts). 583 584 CONFIG_OF_LIBFDT 585 * New libfdt-based support 586 * Adds the "fdt" command 587 * The bootm command automatically updates the fdt 588 589 OF_TBCLK - The timebase frequency. 590 OF_STDOUT_PATH - The path to the console device 591 592 boards with QUICC Engines require OF_QE to set UCC MAC 593 addresses 594 595 CONFIG_OF_BOARD_SETUP 596 597 Board code has addition modification that it wants to make 598 to the flat device tree before handing it off to the kernel 599 600 CONFIG_OF_SYSTEM_SETUP 601 602 Other code has addition modification that it wants to make 603 to the flat device tree before handing it off to the kernel. 604 This causes ft_system_setup() to be called before booting 605 the kernel. 606 607 CONFIG_OF_IDE_FIXUP 608 609 U-Boot can detect if an IDE device is present or not. 610 If not, and this new config option is activated, U-Boot 611 removes the ATA node from the DTS before booting Linux, 612 so the Linux IDE driver does not probe the device and 613 crash. This is needed for buggy hardware (uc101) where 614 no pull down resistor is connected to the signal IDE5V_DD7. 615 616 CONFIG_MACH_TYPE [relevant for ARM only][mandatory] 617 618 This setting is mandatory for all boards that have only one 619 machine type and must be used to specify the machine type 620 number as it appears in the ARM machine registry 621 (see http://www.arm.linux.org.uk/developer/machines/). 622 Only boards that have multiple machine types supported 623 in a single configuration file and the machine type is 624 runtime discoverable, do not have to use this setting. 625 626- vxWorks boot parameters: 627 628 bootvx constructs a valid bootline using the following 629 environments variables: bootdev, bootfile, ipaddr, netmask, 630 serverip, gatewayip, hostname, othbootargs. 631 It loads the vxWorks image pointed bootfile. 632 633 Note: If a "bootargs" environment is defined, it will overwride 634 the defaults discussed just above. 635 636- Cache Configuration: 637 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot 638 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot 639 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot 640 641- Cache Configuration for ARM: 642 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache 643 controller 644 CONFIG_SYS_PL310_BASE - Physical base address of PL310 645 controller register space 646 647- Serial Ports: 648 CONFIG_PL010_SERIAL 649 650 Define this if you want support for Amba PrimeCell PL010 UARTs. 651 652 CONFIG_PL011_SERIAL 653 654 Define this if you want support for Amba PrimeCell PL011 UARTs. 655 656 CONFIG_PL011_CLOCK 657 658 If you have Amba PrimeCell PL011 UARTs, set this variable to 659 the clock speed of the UARTs. 660 661 CONFIG_PL01x_PORTS 662 663 If you have Amba PrimeCell PL010 or PL011 UARTs on your board, 664 define this to a list of base addresses for each (supported) 665 port. See e.g. include/configs/versatile.h 666 667 CONFIG_SERIAL_HW_FLOW_CONTROL 668 669 Define this variable to enable hw flow control in serial driver. 670 Current user of this option is drivers/serial/nsl16550.c driver 671 672- Console Baudrate: 673 CONFIG_BAUDRATE - in bps 674 Select one of the baudrates listed in 675 CONFIG_SYS_BAUDRATE_TABLE, see below. 676 677- Autoboot Command: 678 CONFIG_BOOTCOMMAND 679 Only needed when CONFIG_BOOTDELAY is enabled; 680 define a command string that is automatically executed 681 when no character is read on the console interface 682 within "Boot Delay" after reset. 683 684 CONFIG_RAMBOOT and CONFIG_NFSBOOT 685 The value of these goes into the environment as 686 "ramboot" and "nfsboot" respectively, and can be used 687 as a convenience, when switching between booting from 688 RAM and NFS. 689 690- Pre-Boot Commands: 691 CONFIG_PREBOOT 692 693 When this option is #defined, the existence of the 694 environment variable "preboot" will be checked 695 immediately before starting the CONFIG_BOOTDELAY 696 countdown and/or running the auto-boot command resp. 697 entering interactive mode. 698 699 This feature is especially useful when "preboot" is 700 automatically generated or modified. For an example 701 see the LWMON board specific code: here "preboot" is 702 modified when the user holds down a certain 703 combination of keys on the (special) keyboard when 704 booting the systems 705 706- Serial Download Echo Mode: 707 CONFIG_LOADS_ECHO 708 If defined to 1, all characters received during a 709 serial download (using the "loads" command) are 710 echoed back. This might be needed by some terminal 711 emulations (like "cu"), but may as well just take 712 time on others. This setting #define's the initial 713 value of the "loads_echo" environment variable. 714 715- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined) 716 CONFIG_KGDB_BAUDRATE 717 Select one of the baudrates listed in 718 CONFIG_SYS_BAUDRATE_TABLE, see below. 719 720- Removal of commands 721 If no commands are needed to boot, you can disable 722 CONFIG_CMDLINE to remove them. In this case, the command line 723 will not be available, and when U-Boot wants to execute the 724 boot command (on start-up) it will call board_run_command() 725 instead. This can reduce image size significantly for very 726 simple boot procedures. 727 728- Regular expression support: 729 CONFIG_REGEX 730 If this variable is defined, U-Boot is linked against 731 the SLRE (Super Light Regular Expression) library, 732 which adds regex support to some commands, as for 733 example "env grep" and "setexpr". 734 735- Device tree: 736 CONFIG_OF_CONTROL 737 If this variable is defined, U-Boot will use a device tree 738 to configure its devices, instead of relying on statically 739 compiled #defines in the board file. This option is 740 experimental and only available on a few boards. The device 741 tree is available in the global data as gd->fdt_blob. 742 743 U-Boot needs to get its device tree from somewhere. This can 744 be done using one of the three options below: 745 746 CONFIG_OF_EMBED 747 If this variable is defined, U-Boot will embed a device tree 748 binary in its image. This device tree file should be in the 749 board directory and called <soc>-<board>.dts. The binary file 750 is then picked up in board_init_f() and made available through 751 the global data structure as gd->fdt_blob. 752 753 CONFIG_OF_SEPARATE 754 If this variable is defined, U-Boot will build a device tree 755 binary. It will be called u-boot.dtb. Architecture-specific 756 code will locate it at run-time. Generally this works by: 757 758 cat u-boot.bin u-boot.dtb >image.bin 759 760 and in fact, U-Boot does this for you, creating a file called 761 u-boot-dtb.bin which is useful in the common case. You can 762 still use the individual files if you need something more 763 exotic. 764 765 CONFIG_OF_BOARD 766 If this variable is defined, U-Boot will use the device tree 767 provided by the board at runtime instead of embedding one with 768 the image. Only boards defining board_fdt_blob_setup() support 769 this option (see include/fdtdec.h file). 770 771- Watchdog: 772 CONFIG_WATCHDOG 773 If this variable is defined, it enables watchdog 774 support for the SoC. There must be support in the SoC 775 specific code for a watchdog. For the 8xx 776 CPUs, the SIU Watchdog feature is enabled in the SYPCR 777 register. When supported for a specific SoC is 778 available, then no further board specific code should 779 be needed to use it. 780 781 CONFIG_HW_WATCHDOG 782 When using a watchdog circuitry external to the used 783 SoC, then define this variable and provide board 784 specific code for the "hw_watchdog_reset" function. 785 786 CONFIG_AT91_HW_WDT_TIMEOUT 787 specify the timeout in seconds. default 2 seconds. 788 789- Real-Time Clock: 790 791 When CONFIG_CMD_DATE is selected, the type of the RTC 792 has to be selected, too. Define exactly one of the 793 following options: 794 795 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 796 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC 797 CONFIG_RTC_MC146818 - use MC146818 RTC 798 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 799 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 800 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 801 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC 802 CONFIG_RTC_DS164x - use Dallas DS164x RTC 803 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC 804 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 805 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337 806 CONFIG_SYS_RV3029_TCR - enable trickle charger on 807 RV3029 RTC. 808 809 Note that if the RTC uses I2C, then the I2C interface 810 must also be configured. See I2C Support, below. 811 812- GPIO Support: 813 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO 814 815 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of 816 chip-ngpio pairs that tell the PCA953X driver the number of 817 pins supported by a particular chip. 818 819 Note that if the GPIO device uses I2C, then the I2C interface 820 must also be configured. See I2C Support, below. 821 822- I/O tracing: 823 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O 824 accesses and can checksum them or write a list of them out 825 to memory. See the 'iotrace' command for details. This is 826 useful for testing device drivers since it can confirm that 827 the driver behaves the same way before and after a code 828 change. Currently this is supported on sandbox and arm. To 829 add support for your architecture, add '#include <iotrace.h>' 830 to the bottom of arch/<arch>/include/asm/io.h and test. 831 832 Example output from the 'iotrace stats' command is below. 833 Note that if the trace buffer is exhausted, the checksum will 834 still continue to operate. 835 836 iotrace is enabled 837 Start: 10000000 (buffer start address) 838 Size: 00010000 (buffer size) 839 Offset: 00000120 (current buffer offset) 840 Output: 10000120 (start + offset) 841 Count: 00000018 (number of trace records) 842 CRC32: 9526fb66 (CRC32 of all trace records) 843 844- Timestamp Support: 845 846 When CONFIG_TIMESTAMP is selected, the timestamp 847 (date and time) of an image is printed by image 848 commands like bootm or iminfo. This option is 849 automatically enabled when you select CONFIG_CMD_DATE . 850 851- Partition Labels (disklabels) Supported: 852 Zero or more of the following: 853 CONFIG_MAC_PARTITION Apple's MacOS partition table. 854 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc. 855 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the 856 bootloader. Note 2TB partition limit; see 857 disk/part_efi.c 858 CONFIG_SCSI) you must configure support for at 859 least one non-MTD partition type as well. 860 861- IDE Reset method: 862 CONFIG_IDE_RESET_ROUTINE - this is defined in several 863 board configurations files but used nowhere! 864 865 CONFIG_IDE_RESET - is this is defined, IDE Reset will 866 be performed by calling the function 867 ide_set_reset(int reset) 868 which has to be defined in a board specific file 869 870- ATAPI Support: 871 CONFIG_ATAPI 872 873 Set this to enable ATAPI support. 874 875- LBA48 Support 876 CONFIG_LBA48 877 878 Set this to enable support for disks larger than 137GB 879 Also look at CONFIG_SYS_64BIT_LBA. 880 Whithout these , LBA48 support uses 32bit variables and will 'only' 881 support disks up to 2.1TB. 882 883 CONFIG_SYS_64BIT_LBA: 884 When enabled, makes the IDE subsystem use 64bit sector addresses. 885 Default is 32bit. 886 887- SCSI Support: 888 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and 889 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID * 890 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the 891 maximum numbers of LUNs, SCSI ID's and target 892 devices. 893 894 The environment variable 'scsidevs' is set to the number of 895 SCSI devices found during the last scan. 896 897- NETWORK Support (PCI): 898 CONFIG_E1000 899 Support for Intel 8254x/8257x gigabit chips. 900 901 CONFIG_E1000_SPI 902 Utility code for direct access to the SPI bus on Intel 8257x. 903 This does not do anything useful unless you set at least one 904 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC. 905 906 CONFIG_E1000_SPI_GENERIC 907 Allow generic access to the SPI bus on the Intel 8257x, for 908 example with the "sspi" command. 909 910 CONFIG_EEPRO100 911 Support for Intel 82557/82559/82559ER chips. 912 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM 913 write routine for first time initialisation. 914 915 CONFIG_TULIP 916 Support for Digital 2114x chips. 917 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 918 modem chip initialisation (KS8761/QS6611). 919 920 CONFIG_NATSEMI 921 Support for National dp83815 chips. 922 923 CONFIG_NS8382X 924 Support for National dp8382[01] gigabit chips. 925 926- NETWORK Support (other): 927 928 CONFIG_DRIVER_AT91EMAC 929 Support for AT91RM9200 EMAC. 930 931 CONFIG_RMII 932 Define this to use reduced MII inteface 933 934 CONFIG_DRIVER_AT91EMAC_QUIET 935 If this defined, the driver is quiet. 936 The driver doen't show link status messages. 937 938 CONFIG_CALXEDA_XGMAC 939 Support for the Calxeda XGMAC device 940 941 CONFIG_LAN91C96 942 Support for SMSC's LAN91C96 chips. 943 944 CONFIG_LAN91C96_USE_32_BIT 945 Define this to enable 32 bit addressing 946 947 CONFIG_SMC91111 948 Support for SMSC's LAN91C111 chip 949 950 CONFIG_SMC91111_BASE 951 Define this to hold the physical address 952 of the device (I/O space) 953 954 CONFIG_SMC_USE_32_BIT 955 Define this if data bus is 32 bits 956 957 CONFIG_SMC_USE_IOFUNCS 958 Define this to use i/o functions instead of macros 959 (some hardware wont work with macros) 960 961 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 962 Define this if you have more then 3 PHYs. 963 964 CONFIG_FTGMAC100 965 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 966 967 CONFIG_FTGMAC100_EGIGA 968 Define this to use GE link update with gigabit PHY. 969 Define this if FTGMAC100 is connected to gigabit PHY. 970 If your system has 10/100 PHY only, it might not occur 971 wrong behavior. Because PHY usually return timeout or 972 useless data when polling gigabit status and gigabit 973 control registers. This behavior won't affect the 974 correctnessof 10/100 link speed update. 975 976 CONFIG_SH_ETHER 977 Support for Renesas on-chip Ethernet controller 978 979 CONFIG_SH_ETHER_USE_PORT 980 Define the number of ports to be used 981 982 CONFIG_SH_ETHER_PHY_ADDR 983 Define the ETH PHY's address 984 985 CONFIG_SH_ETHER_CACHE_WRITEBACK 986 If this option is set, the driver enables cache flush. 987 988- PWM Support: 989 CONFIG_PWM_IMX 990 Support for PWM module on the imx6. 991 992- TPM Support: 993 CONFIG_TPM 994 Support TPM devices. 995 996 CONFIG_TPM_TIS_INFINEON 997 Support for Infineon i2c bus TPM devices. Only one device 998 per system is supported at this time. 999 1000 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 1001 Define the burst count bytes upper limit 1002 1003 CONFIG_TPM_ST33ZP24 1004 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 1005 1006 CONFIG_TPM_ST33ZP24_I2C 1007 Support for STMicroelectronics ST33ZP24 I2C devices. 1008 Requires TPM_ST33ZP24 and I2C. 1009 1010 CONFIG_TPM_ST33ZP24_SPI 1011 Support for STMicroelectronics ST33ZP24 SPI devices. 1012 Requires TPM_ST33ZP24 and SPI. 1013 1014 CONFIG_TPM_ATMEL_TWI 1015 Support for Atmel TWI TPM device. Requires I2C support. 1016 1017 CONFIG_TPM_TIS_LPC 1018 Support for generic parallel port TPM devices. Only one device 1019 per system is supported at this time. 1020 1021 CONFIG_TPM_TIS_BASE_ADDRESS 1022 Base address where the generic TPM device is mapped 1023 to. Contemporary x86 systems usually map it at 1024 0xfed40000. 1025 1026 CONFIG_TPM 1027 Define this to enable the TPM support library which provides 1028 functional interfaces to some TPM commands. 1029 Requires support for a TPM device. 1030 1031 CONFIG_TPM_AUTH_SESSIONS 1032 Define this to enable authorized functions in the TPM library. 1033 Requires CONFIG_TPM and CONFIG_SHA1. 1034 1035- USB Support: 1036 At the moment only the UHCI host controller is 1037 supported (PIP405, MIP405); define 1038 CONFIG_USB_UHCI to enable it. 1039 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 1040 and define CONFIG_USB_STORAGE to enable the USB 1041 storage devices. 1042 Note: 1043 Supported are USB Keyboards and USB Floppy drives 1044 (TEAC FD-05PUB). 1045 1046 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 1047 txfilltuning field in the EHCI controller on reset. 1048 1049 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2 1050 HW module registers. 1051 1052- USB Device: 1053 Define the below if you wish to use the USB console. 1054 Once firmware is rebuilt from a serial console issue the 1055 command "setenv stdin usbtty; setenv stdout usbtty" and 1056 attach your USB cable. The Unix command "dmesg" should print 1057 it has found a new device. The environment variable usbtty 1058 can be set to gserial or cdc_acm to enable your device to 1059 appear to a USB host as a Linux gserial device or a 1060 Common Device Class Abstract Control Model serial device. 1061 If you select usbtty = gserial you should be able to enumerate 1062 a Linux host by 1063 # modprobe usbserial vendor=0xVendorID product=0xProductID 1064 else if using cdc_acm, simply setting the environment 1065 variable usbtty to be cdc_acm should suffice. The following 1066 might be defined in YourBoardName.h 1067 1068 CONFIG_USB_DEVICE 1069 Define this to build a UDC device 1070 1071 CONFIG_USB_TTY 1072 Define this to have a tty type of device available to 1073 talk to the UDC device 1074 1075 CONFIG_USBD_HS 1076 Define this to enable the high speed support for usb 1077 device and usbtty. If this feature is enabled, a routine 1078 int is_usbd_high_speed(void) 1079 also needs to be defined by the driver to dynamically poll 1080 whether the enumeration has succeded at high speed or full 1081 speed. 1082 1083 CONFIG_SYS_CONSOLE_IS_IN_ENV 1084 Define this if you want stdin, stdout &/or stderr to 1085 be set to usbtty. 1086 1087 If you have a USB-IF assigned VendorID then you may wish to 1088 define your own vendor specific values either in BoardName.h 1089 or directly in usbd_vendor_info.h. If you don't define 1090 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 1091 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 1092 should pretend to be a Linux device to it's target host. 1093 1094 CONFIG_USBD_MANUFACTURER 1095 Define this string as the name of your company for 1096 - CONFIG_USBD_MANUFACTURER "my company" 1097 1098 CONFIG_USBD_PRODUCT_NAME 1099 Define this string as the name of your product 1100 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 1101 1102 CONFIG_USBD_VENDORID 1103 Define this as your assigned Vendor ID from the USB 1104 Implementors Forum. This *must* be a genuine Vendor ID 1105 to avoid polluting the USB namespace. 1106 - CONFIG_USBD_VENDORID 0xFFFF 1107 1108 CONFIG_USBD_PRODUCTID 1109 Define this as the unique Product ID 1110 for your device 1111 - CONFIG_USBD_PRODUCTID 0xFFFF 1112 1113- ULPI Layer Support: 1114 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 1115 the generic ULPI layer. The generic layer accesses the ULPI PHY 1116 via the platform viewport, so you need both the genric layer and 1117 the viewport enabled. Currently only Chipidea/ARC based 1118 viewport is supported. 1119 To enable the ULPI layer support, define CONFIG_USB_ULPI and 1120 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 1121 If your ULPI phy needs a different reference clock than the 1122 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 1123 the appropriate value in Hz. 1124 1125- MMC Support: 1126 The MMC controller on the Intel PXA is supported. To 1127 enable this define CONFIG_MMC. The MMC can be 1128 accessed from the boot prompt by mapping the device 1129 to physical memory similar to flash. Command line is 1130 enabled with CONFIG_CMD_MMC. The MMC driver also works with 1131 the FAT fs. This is enabled with CONFIG_CMD_FAT. 1132 1133 CONFIG_SH_MMCIF 1134 Support for Renesas on-chip MMCIF controller 1135 1136 CONFIG_SH_MMCIF_ADDR 1137 Define the base address of MMCIF registers 1138 1139 CONFIG_SH_MMCIF_CLK 1140 Define the clock frequency for MMCIF 1141 1142 CONFIG_SUPPORT_EMMC_BOOT 1143 Enable some additional features of the eMMC boot partitions. 1144 1145- USB Device Firmware Update (DFU) class support: 1146 CONFIG_DFU_OVER_USB 1147 This enables the USB portion of the DFU USB class 1148 1149 CONFIG_DFU_NAND 1150 This enables support for exposing NAND devices via DFU. 1151 1152 CONFIG_DFU_RAM 1153 This enables support for exposing RAM via DFU. 1154 Note: DFU spec refer to non-volatile memory usage, but 1155 allow usages beyond the scope of spec - here RAM usage, 1156 one that would help mostly the developer. 1157 1158 CONFIG_SYS_DFU_DATA_BUF_SIZE 1159 Dfu transfer uses a buffer before writing data to the 1160 raw storage device. Make the size (in bytes) of this buffer 1161 configurable. The size of this buffer is also configurable 1162 through the "dfu_bufsiz" environment variable. 1163 1164 CONFIG_SYS_DFU_MAX_FILE_SIZE 1165 When updating files rather than the raw storage device, 1166 we use a static buffer to copy the file into and then write 1167 the buffer once we've been given the whole file. Define 1168 this to the maximum filesize (in bytes) for the buffer. 1169 Default is 4 MiB if undefined. 1170 1171 DFU_DEFAULT_POLL_TIMEOUT 1172 Poll timeout [ms], is the timeout a device can send to the 1173 host. The host must wait for this timeout before sending 1174 a subsequent DFU_GET_STATUS request to the device. 1175 1176 DFU_MANIFEST_POLL_TIMEOUT 1177 Poll timeout [ms], which the device sends to the host when 1178 entering dfuMANIFEST state. Host waits this timeout, before 1179 sending again an USB request to the device. 1180 1181- Journaling Flash filesystem support: 1182 CONFIG_JFFS2_NAND 1183 Define these for a default partition on a NAND device 1184 1185 CONFIG_SYS_JFFS2_FIRST_SECTOR, 1186 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 1187 Define these for a default partition on a NOR device 1188 1189- Keyboard Support: 1190 See Kconfig help for available keyboard drivers. 1191 1192 CONFIG_KEYBOARD 1193 1194 Define this to enable a custom keyboard support. 1195 This simply calls drv_keyboard_init() which must be 1196 defined in your board-specific files. This option is deprecated 1197 and is only used by novena. For new boards, use driver model 1198 instead. 1199 1200- Video support: 1201 CONFIG_FSL_DIU_FB 1202 Enable the Freescale DIU video driver. Reference boards for 1203 SOCs that have a DIU should define this macro to enable DIU 1204 support, and should also define these other macros: 1205 1206 CONFIG_SYS_DIU_ADDR 1207 CONFIG_VIDEO 1208 CONFIG_CFB_CONSOLE 1209 CONFIG_VIDEO_SW_CURSOR 1210 CONFIG_VGA_AS_SINGLE_DEVICE 1211 CONFIG_VIDEO_LOGO 1212 CONFIG_VIDEO_BMP_LOGO 1213 1214 The DIU driver will look for the 'video-mode' environment 1215 variable, and if defined, enable the DIU as a console during 1216 boot. See the documentation file doc/README.video for a 1217 description of this variable. 1218 1219- LCD Support: CONFIG_LCD 1220 1221 Define this to enable LCD support (for output to LCD 1222 display); also select one of the supported displays 1223 by defining one of these: 1224 1225 CONFIG_ATMEL_LCD: 1226 1227 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1228 1229 CONFIG_NEC_NL6448AC33: 1230 1231 NEC NL6448AC33-18. Active, color, single scan. 1232 1233 CONFIG_NEC_NL6448BC20 1234 1235 NEC NL6448BC20-08. 6.5", 640x480. 1236 Active, color, single scan. 1237 1238 CONFIG_NEC_NL6448BC33_54 1239 1240 NEC NL6448BC33-54. 10.4", 640x480. 1241 Active, color, single scan. 1242 1243 CONFIG_SHARP_16x9 1244 1245 Sharp 320x240. Active, color, single scan. 1246 It isn't 16x9, and I am not sure what it is. 1247 1248 CONFIG_SHARP_LQ64D341 1249 1250 Sharp LQ64D341 display, 640x480. 1251 Active, color, single scan. 1252 1253 CONFIG_HLD1045 1254 1255 HLD1045 display, 640x480. 1256 Active, color, single scan. 1257 1258 CONFIG_OPTREX_BW 1259 1260 Optrex CBL50840-2 NF-FW 99 22 M5 1261 or 1262 Hitachi LMG6912RPFC-00T 1263 or 1264 Hitachi SP14Q002 1265 1266 320x240. Black & white. 1267 1268 CONFIG_LCD_ALIGNMENT 1269 1270 Normally the LCD is page-aligned (typically 4KB). If this is 1271 defined then the LCD will be aligned to this value instead. 1272 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1273 here, since it is cheaper to change data cache settings on 1274 a per-section basis. 1275 1276 1277 CONFIG_LCD_ROTATION 1278 1279 Sometimes, for example if the display is mounted in portrait 1280 mode or even if it's mounted landscape but rotated by 180degree, 1281 we need to rotate our content of the display relative to the 1282 framebuffer, so that user can read the messages which are 1283 printed out. 1284 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1285 initialized with a given rotation from "vl_rot" out of 1286 "vidinfo_t" which is provided by the board specific code. 1287 The value for vl_rot is coded as following (matching to 1288 fbcon=rotate:<n> linux-kernel commandline): 1289 0 = no rotation respectively 0 degree 1290 1 = 90 degree rotation 1291 2 = 180 degree rotation 1292 3 = 270 degree rotation 1293 1294 If CONFIG_LCD_ROTATION is not defined, the console will be 1295 initialized with 0degree rotation. 1296 1297 CONFIG_LCD_BMP_RLE8 1298 1299 Support drawing of RLE8-compressed bitmaps on the LCD. 1300 1301 CONFIG_I2C_EDID 1302 1303 Enables an 'i2c edid' command which can read EDID 1304 information over I2C from an attached LCD display. 1305 1306- Splash Screen Support: CONFIG_SPLASH_SCREEN 1307 1308 If this option is set, the environment is checked for 1309 a variable "splashimage". If found, the usual display 1310 of logo, copyright and system information on the LCD 1311 is suppressed and the BMP image at the address 1312 specified in "splashimage" is loaded instead. The 1313 console is redirected to the "nulldev", too. This 1314 allows for a "silent" boot where a splash screen is 1315 loaded very quickly after power-on. 1316 1317 CONFIG_SPLASHIMAGE_GUARD 1318 1319 If this option is set, then U-Boot will prevent the environment 1320 variable "splashimage" from being set to a problematic address 1321 (see doc/README.displaying-bmps). 1322 This option is useful for targets where, due to alignment 1323 restrictions, an improperly aligned BMP image will cause a data 1324 abort. If you think you will not have problems with unaligned 1325 accesses (for example because your toolchain prevents them) 1326 there is no need to set this option. 1327 1328 CONFIG_SPLASH_SCREEN_ALIGN 1329 1330 If this option is set the splash image can be freely positioned 1331 on the screen. Environment variable "splashpos" specifies the 1332 position as "x,y". If a positive number is given it is used as 1333 number of pixel from left/top. If a negative number is given it 1334 is used as number of pixel from right/bottom. You can also 1335 specify 'm' for centering the image. 1336 1337 Example: 1338 setenv splashpos m,m 1339 => image at center of screen 1340 1341 setenv splashpos 30,20 1342 => image at x = 30 and y = 20 1343 1344 setenv splashpos -10,m 1345 => vertically centered image 1346 at x = dspWidth - bmpWidth - 9 1347 1348- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP 1349 1350 If this option is set, additionally to standard BMP 1351 images, gzipped BMP images can be displayed via the 1352 splashscreen support or the bmp command. 1353 1354- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8 1355 1356 If this option is set, 8-bit RLE compressed BMP images 1357 can be displayed via the splashscreen support or the 1358 bmp command. 1359 1360- Compression support: 1361 CONFIG_GZIP 1362 1363 Enabled by default to support gzip compressed images. 1364 1365 CONFIG_BZIP2 1366 1367 If this option is set, support for bzip2 compressed 1368 images is included. If not, only uncompressed and gzip 1369 compressed images are supported. 1370 1371 NOTE: the bzip2 algorithm requires a lot of RAM, so 1372 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should 1373 be at least 4MB. 1374 1375- MII/PHY support: 1376 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1377 1378 The clock frequency of the MII bus 1379 1380 CONFIG_PHY_RESET_DELAY 1381 1382 Some PHY like Intel LXT971A need extra delay after 1383 reset before any MII register access is possible. 1384 For such PHY, set this option to the usec delay 1385 required. (minimum 300usec for LXT971A) 1386 1387 CONFIG_PHY_CMD_DELAY (ppc4xx) 1388 1389 Some PHY like Intel LXT971A need extra delay after 1390 command issued before MII status register can be read 1391 1392- IP address: 1393 CONFIG_IPADDR 1394 1395 Define a default value for the IP address to use for 1396 the default Ethernet interface, in case this is not 1397 determined through e.g. bootp. 1398 (Environment variable "ipaddr") 1399 1400- Server IP address: 1401 CONFIG_SERVERIP 1402 1403 Defines a default value for the IP address of a TFTP 1404 server to contact when using the "tftboot" command. 1405 (Environment variable "serverip") 1406 1407 CONFIG_KEEP_SERVERADDR 1408 1409 Keeps the server's MAC address, in the env 'serveraddr' 1410 for passing to bootargs (like Linux's netconsole option) 1411 1412- Gateway IP address: 1413 CONFIG_GATEWAYIP 1414 1415 Defines a default value for the IP address of the 1416 default router where packets to other networks are 1417 sent to. 1418 (Environment variable "gatewayip") 1419 1420- Subnet mask: 1421 CONFIG_NETMASK 1422 1423 Defines a default value for the subnet mask (or 1424 routing prefix) which is used to determine if an IP 1425 address belongs to the local subnet or needs to be 1426 forwarded through a router. 1427 (Environment variable "netmask") 1428 1429- BOOTP Recovery Mode: 1430 CONFIG_BOOTP_RANDOM_DELAY 1431 1432 If you have many targets in a network that try to 1433 boot using BOOTP, you may want to avoid that all 1434 systems send out BOOTP requests at precisely the same 1435 moment (which would happen for instance at recovery 1436 from a power failure, when all systems will try to 1437 boot, thus flooding the BOOTP server. Defining 1438 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1439 inserted before sending out BOOTP requests. The 1440 following delays are inserted then: 1441 1442 1st BOOTP request: delay 0 ... 1 sec 1443 2nd BOOTP request: delay 0 ... 2 sec 1444 3rd BOOTP request: delay 0 ... 4 sec 1445 4th and following 1446 BOOTP requests: delay 0 ... 8 sec 1447 1448 CONFIG_BOOTP_ID_CACHE_SIZE 1449 1450 BOOTP packets are uniquely identified using a 32-bit ID. The 1451 server will copy the ID from client requests to responses and 1452 U-Boot will use this to determine if it is the destination of 1453 an incoming response. Some servers will check that addresses 1454 aren't in use before handing them out (usually using an ARP 1455 ping) and therefore take up to a few hundred milliseconds to 1456 respond. Network congestion may also influence the time it 1457 takes for a response to make it back to the client. If that 1458 time is too long, U-Boot will retransmit requests. In order 1459 to allow earlier responses to still be accepted after these 1460 retransmissions, U-Boot's BOOTP client keeps a small cache of 1461 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1462 cache. The default is to keep IDs for up to four outstanding 1463 requests. Increasing this will allow U-Boot to accept offers 1464 from a BOOTP client in networks with unusually high latency. 1465 1466- DHCP Advanced Options: 1467 You can fine tune the DHCP functionality by defining 1468 CONFIG_BOOTP_* symbols: 1469 1470 CONFIG_BOOTP_NISDOMAIN 1471 CONFIG_BOOTP_BOOTFILESIZE 1472 CONFIG_BOOTP_SEND_HOSTNAME 1473 CONFIG_BOOTP_NTPSERVER 1474 CONFIG_BOOTP_TIMEOFFSET 1475 CONFIG_BOOTP_VENDOREX 1476 CONFIG_BOOTP_MAY_FAIL 1477 1478 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1479 environment variable, not the BOOTP server. 1480 1481 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1482 after the configured retry count, the call will fail 1483 instead of starting over. This can be used to fail over 1484 to Link-local IP address configuration if the DHCP server 1485 is not available. 1486 1487 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1488 to do a dynamic update of a DNS server. To do this, they 1489 need the hostname of the DHCP requester. 1490 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1491 of the "hostname" environment variable is passed as 1492 option 12 to the DHCP server. 1493 1494 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1495 1496 A 32bit value in microseconds for a delay between 1497 receiving a "DHCP Offer" and sending the "DHCP Request". 1498 This fixes a problem with certain DHCP servers that don't 1499 respond 100% of the time to a "DHCP request". E.g. On an 1500 AT91RM9200 processor running at 180MHz, this delay needed 1501 to be *at least* 15,000 usec before a Windows Server 2003 1502 DHCP server would reply 100% of the time. I recommend at 1503 least 50,000 usec to be safe. The alternative is to hope 1504 that one of the retries will be successful but note that 1505 the DHCP timeout and retry process takes a longer than 1506 this delay. 1507 1508 - Link-local IP address negotiation: 1509 Negotiate with other link-local clients on the local network 1510 for an address that doesn't require explicit configuration. 1511 This is especially useful if a DHCP server cannot be guaranteed 1512 to exist in all environments that the device must operate. 1513 1514 See doc/README.link-local for more information. 1515 1516 - MAC address from environment variables 1517 1518 FDT_SEQ_MACADDR_FROM_ENV 1519 1520 Fix-up device tree with MAC addresses fetched sequentially from 1521 environment variables. This config work on assumption that 1522 non-usable ethernet node of device-tree are either not present 1523 or their status has been marked as "disabled". 1524 1525 - CDP Options: 1526 CONFIG_CDP_DEVICE_ID 1527 1528 The device id used in CDP trigger frames. 1529 1530 CONFIG_CDP_DEVICE_ID_PREFIX 1531 1532 A two character string which is prefixed to the MAC address 1533 of the device. 1534 1535 CONFIG_CDP_PORT_ID 1536 1537 A printf format string which contains the ascii name of 1538 the port. Normally is set to "eth%d" which sets 1539 eth0 for the first Ethernet, eth1 for the second etc. 1540 1541 CONFIG_CDP_CAPABILITIES 1542 1543 A 32bit integer which indicates the device capabilities; 1544 0x00000010 for a normal host which does not forwards. 1545 1546 CONFIG_CDP_VERSION 1547 1548 An ascii string containing the version of the software. 1549 1550 CONFIG_CDP_PLATFORM 1551 1552 An ascii string containing the name of the platform. 1553 1554 CONFIG_CDP_TRIGGER 1555 1556 A 32bit integer sent on the trigger. 1557 1558 CONFIG_CDP_POWER_CONSUMPTION 1559 1560 A 16bit integer containing the power consumption of the 1561 device in .1 of milliwatts. 1562 1563 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1564 1565 A byte containing the id of the VLAN. 1566 1567- Status LED: CONFIG_LED_STATUS 1568 1569 Several configurations allow to display the current 1570 status using a LED. For instance, the LED will blink 1571 fast while running U-Boot code, stop blinking as 1572 soon as a reply to a BOOTP request was received, and 1573 start blinking slow once the Linux kernel is running 1574 (supported by a status LED driver in the Linux 1575 kernel). Defining CONFIG_LED_STATUS enables this 1576 feature in U-Boot. 1577 1578 Additional options: 1579 1580 CONFIG_LED_STATUS_GPIO 1581 The status LED can be connected to a GPIO pin. 1582 In such cases, the gpio_led driver can be used as a 1583 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1584 to include the gpio_led driver in the U-Boot binary. 1585 1586 CONFIG_GPIO_LED_INVERTED_TABLE 1587 Some GPIO connected LEDs may have inverted polarity in which 1588 case the GPIO high value corresponds to LED off state and 1589 GPIO low value corresponds to LED on state. 1590 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1591 with a list of GPIO LEDs that have inverted polarity. 1592 1593- I2C Support: CONFIG_SYS_I2C 1594 1595 This enable the NEW i2c subsystem, and will allow you to use 1596 i2c commands at the u-boot command line (as long as you set 1597 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c 1598 based realtime clock chips or other i2c devices. See 1599 common/cmd_i2c.c for a description of the command line 1600 interface. 1601 1602 ported i2c driver to the new framework: 1603 - drivers/i2c/soft_i2c.c: 1604 - activate first bus with CONFIG_SYS_I2C_SOFT define 1605 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1606 for defining speed and slave address 1607 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1608 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1609 for defining speed and slave address 1610 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1611 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1612 for defining speed and slave address 1613 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1614 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1615 for defining speed and slave address 1616 1617 - drivers/i2c/fsl_i2c.c: 1618 - activate i2c driver with CONFIG_SYS_I2C_FSL 1619 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1620 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1621 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1622 bus. 1623 - If your board supports a second fsl i2c bus, define 1624 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1625 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1626 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1627 second bus. 1628 1629 - drivers/i2c/tegra_i2c.c: 1630 - activate this driver with CONFIG_SYS_I2C_TEGRA 1631 - This driver adds 4 i2c buses with a fix speed from 1632 100000 and the slave addr 0! 1633 1634 - drivers/i2c/ppc4xx_i2c.c 1635 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1636 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1637 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1638 1639 - drivers/i2c/i2c_mxc.c 1640 - activate this driver with CONFIG_SYS_I2C_MXC 1641 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1642 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1643 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1644 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1645 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1646 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1647 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1648 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1649 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1650 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1651 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1652 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1653 If those defines are not set, default value is 100000 1654 for speed, and 0 for slave. 1655 1656 - drivers/i2c/rcar_i2c.c: 1657 - activate this driver with CONFIG_SYS_I2C_RCAR 1658 - This driver adds 4 i2c buses 1659 1660 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0 1661 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0 1662 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1 1663 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1 1664 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2 1665 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2 1666 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3 1667 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3 1668 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses 1669 1670 - drivers/i2c/sh_i2c.c: 1671 - activate this driver with CONFIG_SYS_I2C_SH 1672 - This driver adds from 2 to 5 i2c buses 1673 1674 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1675 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1676 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1677 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1678 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1679 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1680 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1681 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1682 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1683 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1684 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1685 1686 - drivers/i2c/omap24xx_i2c.c 1687 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1688 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1689 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1690 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1691 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1692 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1693 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1694 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1695 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1696 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1697 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1698 1699 - drivers/i2c/zynq_i2c.c 1700 - activate this driver with CONFIG_SYS_I2C_ZYNQ 1701 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting 1702 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr 1703 1704 - drivers/i2c/s3c24x0_i2c.c: 1705 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1706 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1707 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1708 with a fix speed from 100000 and the slave addr 0! 1709 1710 - drivers/i2c/ihs_i2c.c 1711 - activate this driver with CONFIG_SYS_I2C_IHS 1712 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1713 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1714 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1715 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1716 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1717 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1718 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1719 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1720 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1721 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1722 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1723 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1724 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1725 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1726 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1727 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1728 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1729 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1730 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1731 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1732 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1733 1734 additional defines: 1735 1736 CONFIG_SYS_NUM_I2C_BUSES 1737 Hold the number of i2c buses you want to use. 1738 1739 CONFIG_SYS_I2C_DIRECT_BUS 1740 define this, if you don't use i2c muxes on your hardware. 1741 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1742 omit this define. 1743 1744 CONFIG_SYS_I2C_MAX_HOPS 1745 define how many muxes are maximal consecutively connected 1746 on one i2c bus. If you not use i2c muxes, omit this 1747 define. 1748 1749 CONFIG_SYS_I2C_BUSES 1750 hold a list of buses you want to use, only used if 1751 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1752 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1753 CONFIG_SYS_NUM_I2C_BUSES = 9: 1754 1755 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1756 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1757 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1758 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1759 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1760 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1761 {1, {I2C_NULL_HOP}}, \ 1762 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1763 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1764 } 1765 1766 which defines 1767 bus 0 on adapter 0 without a mux 1768 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1769 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1770 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1771 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1772 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1773 bus 6 on adapter 1 without a mux 1774 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1775 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1776 1777 If you do not have i2c muxes on your board, omit this define. 1778 1779- Legacy I2C Support: 1780 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1781 then the following macros need to be defined (examples are 1782 from include/configs/lwmon.h): 1783 1784 I2C_INIT 1785 1786 (Optional). Any commands necessary to enable the I2C 1787 controller or configure ports. 1788 1789 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1790 1791 I2C_ACTIVE 1792 1793 The code necessary to make the I2C data line active 1794 (driven). If the data line is open collector, this 1795 define can be null. 1796 1797 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1798 1799 I2C_TRISTATE 1800 1801 The code necessary to make the I2C data line tri-stated 1802 (inactive). If the data line is open collector, this 1803 define can be null. 1804 1805 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1806 1807 I2C_READ 1808 1809 Code that returns true if the I2C data line is high, 1810 false if it is low. 1811 1812 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1813 1814 I2C_SDA(bit) 1815 1816 If <bit> is true, sets the I2C data line high. If it 1817 is false, it clears it (low). 1818 1819 eg: #define I2C_SDA(bit) \ 1820 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1821 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1822 1823 I2C_SCL(bit) 1824 1825 If <bit> is true, sets the I2C clock line high. If it 1826 is false, it clears it (low). 1827 1828 eg: #define I2C_SCL(bit) \ 1829 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1830 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1831 1832 I2C_DELAY 1833 1834 This delay is invoked four times per clock cycle so this 1835 controls the rate of data transfer. The data rate thus 1836 is 1 / (I2C_DELAY * 4). Often defined to be something 1837 like: 1838 1839 #define I2C_DELAY udelay(2) 1840 1841 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1842 1843 If your arch supports the generic GPIO framework (asm/gpio.h), 1844 then you may alternatively define the two GPIOs that are to be 1845 used as SCL / SDA. Any of the previous I2C_xxx macros will 1846 have GPIO-based defaults assigned to them as appropriate. 1847 1848 You should define these to the GPIO value as given directly to 1849 the generic GPIO functions. 1850 1851 CONFIG_SYS_I2C_INIT_BOARD 1852 1853 When a board is reset during an i2c bus transfer 1854 chips might think that the current transfer is still 1855 in progress. On some boards it is possible to access 1856 the i2c SCLK line directly, either by using the 1857 processor pin as a GPIO or by having a second pin 1858 connected to the bus. If this option is defined a 1859 custom i2c_init_board() routine in boards/xxx/board.c 1860 is run early in the boot sequence. 1861 1862 CONFIG_I2C_MULTI_BUS 1863 1864 This option allows the use of multiple I2C buses, each of which 1865 must have a controller. At any point in time, only one bus is 1866 active. To switch to a different bus, use the 'i2c dev' command. 1867 Note that bus numbering is zero-based. 1868 1869 CONFIG_SYS_I2C_NOPROBES 1870 1871 This option specifies a list of I2C devices that will be skipped 1872 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1873 is set, specify a list of bus-device pairs. Otherwise, specify 1874 a 1D array of device addresses 1875 1876 e.g. 1877 #undef CONFIG_I2C_MULTI_BUS 1878 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1879 1880 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1881 1882 #define CONFIG_I2C_MULTI_BUS 1883 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1884 1885 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1886 1887 CONFIG_SYS_SPD_BUS_NUM 1888 1889 If defined, then this indicates the I2C bus number for DDR SPD. 1890 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1891 1892 CONFIG_SYS_RTC_BUS_NUM 1893 1894 If defined, then this indicates the I2C bus number for the RTC. 1895 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1896 1897 CONFIG_SOFT_I2C_READ_REPEATED_START 1898 1899 defining this will force the i2c_read() function in 1900 the soft_i2c driver to perform an I2C repeated start 1901 between writing the address pointer and reading the 1902 data. If this define is omitted the default behaviour 1903 of doing a stop-start sequence will be used. Most I2C 1904 devices can use either method, but some require one or 1905 the other. 1906 1907- SPI Support: CONFIG_SPI 1908 1909 Enables SPI driver (so far only tested with 1910 SPI EEPROM, also an instance works with Crystal A/D and 1911 D/As on the SACSng board) 1912 1913 CONFIG_SOFT_SPI 1914 1915 Enables a software (bit-bang) SPI driver rather than 1916 using hardware support. This is a general purpose 1917 driver that only requires three general I/O port pins 1918 (two outputs, one input) to function. If this is 1919 defined, the board configuration must define several 1920 SPI configuration items (port pins to use, etc). For 1921 an example, see include/configs/sacsng.h. 1922 1923 CONFIG_SYS_SPI_MXC_WAIT 1924 Timeout for waiting until spi transfer completed. 1925 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1926 1927- FPGA Support: CONFIG_FPGA 1928 1929 Enables FPGA subsystem. 1930 1931 CONFIG_FPGA_<vendor> 1932 1933 Enables support for specific chip vendors. 1934 (ALTERA, XILINX) 1935 1936 CONFIG_FPGA_<family> 1937 1938 Enables support for FPGA family. 1939 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1940 1941 CONFIG_FPGA_COUNT 1942 1943 Specify the number of FPGA devices to support. 1944 1945 CONFIG_SYS_FPGA_PROG_FEEDBACK 1946 1947 Enable printing of hash marks during FPGA configuration. 1948 1949 CONFIG_SYS_FPGA_CHECK_BUSY 1950 1951 Enable checks on FPGA configuration interface busy 1952 status by the configuration function. This option 1953 will require a board or device specific function to 1954 be written. 1955 1956 CONFIG_FPGA_DELAY 1957 1958 If defined, a function that provides delays in the FPGA 1959 configuration driver. 1960 1961 CONFIG_SYS_FPGA_CHECK_CTRLC 1962 Allow Control-C to interrupt FPGA configuration 1963 1964 CONFIG_SYS_FPGA_CHECK_ERROR 1965 1966 Check for configuration errors during FPGA bitfile 1967 loading. For example, abort during Virtex II 1968 configuration if the INIT_B line goes low (which 1969 indicated a CRC error). 1970 1971 CONFIG_SYS_FPGA_WAIT_INIT 1972 1973 Maximum time to wait for the INIT_B line to de-assert 1974 after PROB_B has been de-asserted during a Virtex II 1975 FPGA configuration sequence. The default time is 500 1976 ms. 1977 1978 CONFIG_SYS_FPGA_WAIT_BUSY 1979 1980 Maximum time to wait for BUSY to de-assert during 1981 Virtex II FPGA configuration. The default is 5 ms. 1982 1983 CONFIG_SYS_FPGA_WAIT_CONFIG 1984 1985 Time to wait after FPGA configuration. The default is 1986 200 ms. 1987 1988- Configuration Management: 1989 CONFIG_BUILD_TARGET 1990 1991 Some SoCs need special image types (e.g. U-Boot binary 1992 with a special header) as build targets. By defining 1993 CONFIG_BUILD_TARGET in the SoC / board header, this 1994 special image will be automatically built upon calling 1995 make / buildman. 1996 1997 CONFIG_IDENT_STRING 1998 1999 If defined, this string will be added to the U-Boot 2000 version information (U_BOOT_VERSION) 2001 2002- Vendor Parameter Protection: 2003 2004 U-Boot considers the values of the environment 2005 variables "serial#" (Board Serial Number) and 2006 "ethaddr" (Ethernet Address) to be parameters that 2007 are set once by the board vendor / manufacturer, and 2008 protects these variables from casual modification by 2009 the user. Once set, these variables are read-only, 2010 and write or delete attempts are rejected. You can 2011 change this behaviour: 2012 2013 If CONFIG_ENV_OVERWRITE is #defined in your config 2014 file, the write protection for vendor parameters is 2015 completely disabled. Anybody can change or delete 2016 these parameters. 2017 2018 Alternatively, if you define _both_ an ethaddr in the 2019 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 2020 Ethernet address is installed in the environment, 2021 which can be changed exactly ONCE by the user. [The 2022 serial# is unaffected by this, i. e. it remains 2023 read-only.] 2024 2025 The same can be accomplished in a more flexible way 2026 for any variable by configuring the type of access 2027 to allow for those variables in the ".flags" variable 2028 or define CONFIG_ENV_FLAGS_LIST_STATIC. 2029 2030- Protected RAM: 2031 CONFIG_PRAM 2032 2033 Define this variable to enable the reservation of 2034 "protected RAM", i. e. RAM which is not overwritten 2035 by U-Boot. Define CONFIG_PRAM to hold the number of 2036 kB you want to reserve for pRAM. You can overwrite 2037 this default value by defining an environment 2038 variable "pram" to the number of kB you want to 2039 reserve. Note that the board info structure will 2040 still show the full amount of RAM. If pRAM is 2041 reserved, a new environment variable "mem" will 2042 automatically be defined to hold the amount of 2043 remaining RAM in a form that can be passed as boot 2044 argument to Linux, for instance like that: 2045 2046 setenv bootargs ... mem=\${mem} 2047 saveenv 2048 2049 This way you can tell Linux not to use this memory, 2050 either, which results in a memory region that will 2051 not be affected by reboots. 2052 2053 *WARNING* If your board configuration uses automatic 2054 detection of the RAM size, you must make sure that 2055 this memory test is non-destructive. So far, the 2056 following board configurations are known to be 2057 "pRAM-clean": 2058 2059 IVMS8, IVML24, SPD8xx, 2060 HERMES, IP860, RPXlite, LWMON, 2061 FLAGADM 2062 2063- Access to physical memory region (> 4GB) 2064 Some basic support is provided for operations on memory not 2065 normally accessible to U-Boot - e.g. some architectures 2066 support access to more than 4GB of memory on 32-bit 2067 machines using physical address extension or similar. 2068 Define CONFIG_PHYSMEM to access this basic support, which 2069 currently only supports clearing the memory. 2070 2071- Error Recovery: 2072 CONFIG_NET_RETRY_COUNT 2073 2074 This variable defines the number of retries for 2075 network operations like ARP, RARP, TFTP, or BOOTP 2076 before giving up the operation. If not defined, a 2077 default value of 5 is used. 2078 2079 CONFIG_ARP_TIMEOUT 2080 2081 Timeout waiting for an ARP reply in milliseconds. 2082 2083 CONFIG_NFS_TIMEOUT 2084 2085 Timeout in milliseconds used in NFS protocol. 2086 If you encounter "ERROR: Cannot umount" in nfs command, 2087 try longer timeout such as 2088 #define CONFIG_NFS_TIMEOUT 10000UL 2089 2090- Command Interpreter: 2091 CONFIG_SYS_PROMPT_HUSH_PS2 2092 2093 This defines the secondary prompt string, which is 2094 printed when the command interpreter needs more input 2095 to complete a command. Usually "> ". 2096 2097 Note: 2098 2099 In the current implementation, the local variables 2100 space and global environment variables space are 2101 separated. Local variables are those you define by 2102 simply typing `name=value'. To access a local 2103 variable later on, you have write `$name' or 2104 `${name}'; to execute the contents of a variable 2105 directly type `$name' at the command prompt. 2106 2107 Global environment variables are those you use 2108 setenv/printenv to work with. To run a command stored 2109 in such a variable, you need to use the run command, 2110 and you must not use the '$' sign to access them. 2111 2112 To store commands and special characters in a 2113 variable, please use double quotation marks 2114 surrounding the whole text of the variable, instead 2115 of the backslashes before semicolons and special 2116 symbols. 2117 2118- Command Line Editing and History: 2119 CONFIG_CMDLINE_PS_SUPPORT 2120 2121 Enable support for changing the command prompt string 2122 at run-time. Only static string is supported so far. 2123 The string is obtained from environment variables PS1 2124 and PS2. 2125 2126- Default Environment: 2127 CONFIG_EXTRA_ENV_SETTINGS 2128 2129 Define this to contain any number of null terminated 2130 strings (variable = value pairs) that will be part of 2131 the default environment compiled into the boot image. 2132 2133 For example, place something like this in your 2134 board's config file: 2135 2136 #define CONFIG_EXTRA_ENV_SETTINGS \ 2137 "myvar1=value1\0" \ 2138 "myvar2=value2\0" 2139 2140 Warning: This method is based on knowledge about the 2141 internal format how the environment is stored by the 2142 U-Boot code. This is NOT an official, exported 2143 interface! Although it is unlikely that this format 2144 will change soon, there is no guarantee either. 2145 You better know what you are doing here. 2146 2147 Note: overly (ab)use of the default environment is 2148 discouraged. Make sure to check other ways to preset 2149 the environment like the "source" command or the 2150 boot command first. 2151 2152 CONFIG_DELAY_ENVIRONMENT 2153 2154 Normally the environment is loaded when the board is 2155 initialised so that it is available to U-Boot. This inhibits 2156 that so that the environment is not available until 2157 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 2158 this is instead controlled by the value of 2159 /config/load-environment. 2160 2161- Serial Flash support 2162 Usage requires an initial 'sf probe' to define the serial 2163 flash parameters, followed by read/write/erase/update 2164 commands. 2165 2166 The following defaults may be provided by the platform 2167 to handle the common case when only a single serial 2168 flash is present on the system. 2169 2170 CONFIG_SF_DEFAULT_BUS Bus identifier 2171 CONFIG_SF_DEFAULT_CS Chip-select 2172 CONFIG_SF_DEFAULT_MODE (see include/spi.h) 2173 CONFIG_SF_DEFAULT_SPEED in Hz 2174 2175 2176- TFTP Fixed UDP Port: 2177 CONFIG_TFTP_PORT 2178 2179 If this is defined, the environment variable tftpsrcp 2180 is used to supply the TFTP UDP source port value. 2181 If tftpsrcp isn't defined, the normal pseudo-random port 2182 number generator is used. 2183 2184 Also, the environment variable tftpdstp is used to supply 2185 the TFTP UDP destination port value. If tftpdstp isn't 2186 defined, the normal port 69 is used. 2187 2188 The purpose for tftpsrcp is to allow a TFTP server to 2189 blindly start the TFTP transfer using the pre-configured 2190 target IP address and UDP port. This has the effect of 2191 "punching through" the (Windows XP) firewall, allowing 2192 the remainder of the TFTP transfer to proceed normally. 2193 A better solution is to properly configure the firewall, 2194 but sometimes that is not allowed. 2195 2196- Show boot progress: 2197 CONFIG_SHOW_BOOT_PROGRESS 2198 2199 Defining this option allows to add some board- 2200 specific code (calling a user-provided function 2201 "show_boot_progress(int)") that enables you to show 2202 the system's boot progress on some display (for 2203 example, some LED's) on your board. At the moment, 2204 the following checkpoints are implemented: 2205 2206 2207Legacy uImage format: 2208 2209 Arg Where When 2210 1 common/cmd_bootm.c before attempting to boot an image 2211 -1 common/cmd_bootm.c Image header has bad magic number 2212 2 common/cmd_bootm.c Image header has correct magic number 2213 -2 common/cmd_bootm.c Image header has bad checksum 2214 3 common/cmd_bootm.c Image header has correct checksum 2215 -3 common/cmd_bootm.c Image data has bad checksum 2216 4 common/cmd_bootm.c Image data has correct checksum 2217 -4 common/cmd_bootm.c Image is for unsupported architecture 2218 5 common/cmd_bootm.c Architecture check OK 2219 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi) 2220 6 common/cmd_bootm.c Image Type check OK 2221 -6 common/cmd_bootm.c gunzip uncompression error 2222 -7 common/cmd_bootm.c Unimplemented compression type 2223 7 common/cmd_bootm.c Uncompression OK 2224 8 common/cmd_bootm.c No uncompress/copy overwrite error 2225 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 2226 2227 9 common/image.c Start initial ramdisk verification 2228 -10 common/image.c Ramdisk header has bad magic number 2229 -11 common/image.c Ramdisk header has bad checksum 2230 10 common/image.c Ramdisk header is OK 2231 -12 common/image.c Ramdisk data has bad checksum 2232 11 common/image.c Ramdisk data has correct checksum 2233 12 common/image.c Ramdisk verification complete, start loading 2234 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk) 2235 13 common/image.c Start multifile image verification 2236 14 common/image.c No initial ramdisk, no multifile, continue. 2237 2238 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS 2239 2240 -30 arch/powerpc/lib/board.c Fatal error, hang the system 2241 -31 post/post.c POST test failed, detected by post_output_backlog() 2242 -32 post/post.c POST test failed, detected by post_run_single() 2243 2244 34 common/cmd_doc.c before loading a Image from a DOC device 2245 -35 common/cmd_doc.c Bad usage of "doc" command 2246 35 common/cmd_doc.c correct usage of "doc" command 2247 -36 common/cmd_doc.c No boot device 2248 36 common/cmd_doc.c correct boot device 2249 -37 common/cmd_doc.c Unknown Chip ID on boot device 2250 37 common/cmd_doc.c correct chip ID found, device available 2251 -38 common/cmd_doc.c Read Error on boot device 2252 38 common/cmd_doc.c reading Image header from DOC device OK 2253 -39 common/cmd_doc.c Image header has bad magic number 2254 39 common/cmd_doc.c Image header has correct magic number 2255 -40 common/cmd_doc.c Error reading Image from DOC device 2256 40 common/cmd_doc.c Image header has correct magic number 2257 41 common/cmd_ide.c before loading a Image from a IDE device 2258 -42 common/cmd_ide.c Bad usage of "ide" command 2259 42 common/cmd_ide.c correct usage of "ide" command 2260 -43 common/cmd_ide.c No boot device 2261 43 common/cmd_ide.c boot device found 2262 -44 common/cmd_ide.c Device not available 2263 44 common/cmd_ide.c Device available 2264 -45 common/cmd_ide.c wrong partition selected 2265 45 common/cmd_ide.c partition selected 2266 -46 common/cmd_ide.c Unknown partition table 2267 46 common/cmd_ide.c valid partition table found 2268 -47 common/cmd_ide.c Invalid partition type 2269 47 common/cmd_ide.c correct partition type 2270 -48 common/cmd_ide.c Error reading Image Header on boot device 2271 48 common/cmd_ide.c reading Image Header from IDE device OK 2272 -49 common/cmd_ide.c Image header has bad magic number 2273 49 common/cmd_ide.c Image header has correct magic number 2274 -50 common/cmd_ide.c Image header has bad checksum 2275 50 common/cmd_ide.c Image header has correct checksum 2276 -51 common/cmd_ide.c Error reading Image from IDE device 2277 51 common/cmd_ide.c reading Image from IDE device OK 2278 52 common/cmd_nand.c before loading a Image from a NAND device 2279 -53 common/cmd_nand.c Bad usage of "nand" command 2280 53 common/cmd_nand.c correct usage of "nand" command 2281 -54 common/cmd_nand.c No boot device 2282 54 common/cmd_nand.c boot device found 2283 -55 common/cmd_nand.c Unknown Chip ID on boot device 2284 55 common/cmd_nand.c correct chip ID found, device available 2285 -56 common/cmd_nand.c Error reading Image Header on boot device 2286 56 common/cmd_nand.c reading Image Header from NAND device OK 2287 -57 common/cmd_nand.c Image header has bad magic number 2288 57 common/cmd_nand.c Image header has correct magic number 2289 -58 common/cmd_nand.c Error reading Image from NAND device 2290 58 common/cmd_nand.c reading Image from NAND device OK 2291 2292 -60 common/env_common.c Environment has a bad CRC, using default 2293 2294 64 net/eth.c starting with Ethernet configuration. 2295 -64 net/eth.c no Ethernet found. 2296 65 net/eth.c Ethernet found. 2297 2298 -80 common/cmd_net.c usage wrong 2299 80 common/cmd_net.c before calling net_loop() 2300 -81 common/cmd_net.c some error in net_loop() occurred 2301 81 common/cmd_net.c net_loop() back without error 2302 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 2303 82 common/cmd_net.c trying automatic boot 2304 83 common/cmd_net.c running "source" command 2305 -83 common/cmd_net.c some error in automatic boot or "source" command 2306 84 common/cmd_net.c end without errors 2307 2308FIT uImage format: 2309 2310 Arg Where When 2311 100 common/cmd_bootm.c Kernel FIT Image has correct format 2312 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format 2313 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration 2314 -101 common/cmd_bootm.c Can't get configuration for kernel subimage 2315 102 common/cmd_bootm.c Kernel unit name specified 2316 -103 common/cmd_bootm.c Can't get kernel subimage node offset 2317 103 common/cmd_bootm.c Found configuration node 2318 104 common/cmd_bootm.c Got kernel subimage node offset 2319 -104 common/cmd_bootm.c Kernel subimage hash verification failed 2320 105 common/cmd_bootm.c Kernel subimage hash verification OK 2321 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture 2322 106 common/cmd_bootm.c Architecture check OK 2323 -106 common/cmd_bootm.c Kernel subimage has wrong type 2324 107 common/cmd_bootm.c Kernel subimage type OK 2325 -107 common/cmd_bootm.c Can't get kernel subimage data/size 2326 108 common/cmd_bootm.c Got kernel subimage data/size 2327 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT) 2328 -109 common/cmd_bootm.c Can't get kernel subimage type 2329 -110 common/cmd_bootm.c Can't get kernel subimage comp 2330 -111 common/cmd_bootm.c Can't get kernel subimage os 2331 -112 common/cmd_bootm.c Can't get kernel subimage load address 2332 -113 common/cmd_bootm.c Image uncompress/copy overwrite error 2333 2334 120 common/image.c Start initial ramdisk verification 2335 -120 common/image.c Ramdisk FIT image has incorrect format 2336 121 common/image.c Ramdisk FIT image has correct format 2337 122 common/image.c No ramdisk subimage unit name, using configuration 2338 -122 common/image.c Can't get configuration for ramdisk subimage 2339 123 common/image.c Ramdisk unit name specified 2340 -124 common/image.c Can't get ramdisk subimage node offset 2341 125 common/image.c Got ramdisk subimage node offset 2342 -125 common/image.c Ramdisk subimage hash verification failed 2343 126 common/image.c Ramdisk subimage hash verification OK 2344 -126 common/image.c Ramdisk subimage for unsupported architecture 2345 127 common/image.c Architecture check OK 2346 -127 common/image.c Can't get ramdisk subimage data/size 2347 128 common/image.c Got ramdisk subimage data/size 2348 129 common/image.c Can't get ramdisk load address 2349 -129 common/image.c Got ramdisk load address 2350 2351 -130 common/cmd_doc.c Incorrect FIT image format 2352 131 common/cmd_doc.c FIT image format OK 2353 2354 -140 common/cmd_ide.c Incorrect FIT image format 2355 141 common/cmd_ide.c FIT image format OK 2356 2357 -150 common/cmd_nand.c Incorrect FIT image format 2358 151 common/cmd_nand.c FIT image format OK 2359 2360- Standalone program support: 2361 CONFIG_STANDALONE_LOAD_ADDR 2362 2363 This option defines a board specific value for the 2364 address where standalone program gets loaded, thus 2365 overwriting the architecture dependent default 2366 settings. 2367 2368- Frame Buffer Address: 2369 CONFIG_FB_ADDR 2370 2371 Define CONFIG_FB_ADDR if you want to use specific 2372 address for frame buffer. This is typically the case 2373 when using a graphics controller has separate video 2374 memory. U-Boot will then place the frame buffer at 2375 the given address instead of dynamically reserving it 2376 in system RAM by calling lcd_setmem(), which grabs 2377 the memory for the frame buffer depending on the 2378 configured panel size. 2379 2380 Please see board_init_f function. 2381 2382- Automatic software updates via TFTP server 2383 CONFIG_UPDATE_TFTP 2384 CONFIG_UPDATE_TFTP_CNT_MAX 2385 CONFIG_UPDATE_TFTP_MSEC_MAX 2386 2387 These options enable and control the auto-update feature; 2388 for a more detailed description refer to doc/README.update. 2389 2390- MTD Support (mtdparts command, UBI support) 2391 CONFIG_MTD_UBI_WL_THRESHOLD 2392 This parameter defines the maximum difference between the highest 2393 erase counter value and the lowest erase counter value of eraseblocks 2394 of UBI devices. When this threshold is exceeded, UBI starts performing 2395 wear leveling by means of moving data from eraseblock with low erase 2396 counter to eraseblocks with high erase counter. 2397 2398 The default value should be OK for SLC NAND flashes, NOR flashes and 2399 other flashes which have eraseblock life-cycle 100000 or more. 2400 However, in case of MLC NAND flashes which typically have eraseblock 2401 life-cycle less than 10000, the threshold should be lessened (e.g., 2402 to 128 or 256, although it does not have to be power of 2). 2403 2404 default: 4096 2405 2406 CONFIG_MTD_UBI_BEB_LIMIT 2407 This option specifies the maximum bad physical eraseblocks UBI 2408 expects on the MTD device (per 1024 eraseblocks). If the 2409 underlying flash does not admit of bad eraseblocks (e.g. NOR 2410 flash), this value is ignored. 2411 2412 NAND datasheets often specify the minimum and maximum NVM 2413 (Number of Valid Blocks) for the flashes' endurance lifetime. 2414 The maximum expected bad eraseblocks per 1024 eraseblocks 2415 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2416 which gives 20 for most NANDs (MaxNVB is basically the total 2417 count of eraseblocks on the chip). 2418 2419 To put it differently, if this value is 20, UBI will try to 2420 reserve about 1.9% of physical eraseblocks for bad blocks 2421 handling. And that will be 1.9% of eraseblocks on the entire 2422 NAND chip, not just the MTD partition UBI attaches. This means 2423 that if you have, say, a NAND flash chip admits maximum 40 bad 2424 eraseblocks, and it is split on two MTD partitions of the same 2425 size, UBI will reserve 40 eraseblocks when attaching a 2426 partition. 2427 2428 default: 20 2429 2430 CONFIG_MTD_UBI_FASTMAP 2431 Fastmap is a mechanism which allows attaching an UBI device 2432 in nearly constant time. Instead of scanning the whole MTD device it 2433 only has to locate a checkpoint (called fastmap) on the device. 2434 The on-flash fastmap contains all information needed to attach 2435 the device. Using fastmap makes only sense on large devices where 2436 attaching by scanning takes long. UBI will not automatically install 2437 a fastmap on old images, but you can set the UBI parameter 2438 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2439 that fastmap-enabled images are still usable with UBI implementations 2440 without fastmap support. On typical flash devices the whole fastmap 2441 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2442 2443 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2444 Set this parameter to enable fastmap automatically on images 2445 without a fastmap. 2446 default: 0 2447 2448 CONFIG_MTD_UBI_FM_DEBUG 2449 Enable UBI fastmap debug 2450 default: 0 2451 2452- SPL framework 2453 CONFIG_SPL 2454 Enable building of SPL globally. 2455 2456 CONFIG_SPL_LDSCRIPT 2457 LDSCRIPT for linking the SPL binary. 2458 2459 CONFIG_SPL_MAX_FOOTPRINT 2460 Maximum size in memory allocated to the SPL, BSS included. 2461 When defined, the linker checks that the actual memory 2462 used by SPL from _start to __bss_end does not exceed it. 2463 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2464 must not be both defined at the same time. 2465 2466 CONFIG_SPL_MAX_SIZE 2467 Maximum size of the SPL image (text, data, rodata, and 2468 linker lists sections), BSS excluded. 2469 When defined, the linker checks that the actual size does 2470 not exceed it. 2471 2472 CONFIG_SPL_TEXT_BASE 2473 TEXT_BASE for linking the SPL binary. 2474 2475 CONFIG_SPL_RELOC_TEXT_BASE 2476 Address to relocate to. If unspecified, this is equal to 2477 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2478 2479 CONFIG_SPL_BSS_START_ADDR 2480 Link address for the BSS within the SPL binary. 2481 2482 CONFIG_SPL_BSS_MAX_SIZE 2483 Maximum size in memory allocated to the SPL BSS. 2484 When defined, the linker checks that the actual memory used 2485 by SPL from __bss_start to __bss_end does not exceed it. 2486 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2487 must not be both defined at the same time. 2488 2489 CONFIG_SPL_STACK 2490 Adress of the start of the stack SPL will use 2491 2492 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2493 When defined, SPL will panic() if the image it has 2494 loaded does not have a signature. 2495 Defining this is useful when code which loads images 2496 in SPL cannot guarantee that absolutely all read errors 2497 will be caught. 2498 An example is the LPC32XX MLC NAND driver, which will 2499 consider that a completely unreadable NAND block is bad, 2500 and thus should be skipped silently. 2501 2502 CONFIG_SPL_RELOC_STACK 2503 Adress of the start of the stack SPL will use after 2504 relocation. If unspecified, this is equal to 2505 CONFIG_SPL_STACK. 2506 2507 CONFIG_SYS_SPL_MALLOC_START 2508 Starting address of the malloc pool used in SPL. 2509 When this option is set the full malloc is used in SPL and 2510 it is set up by spl_init() and before that, the simple malloc() 2511 can be used if CONFIG_SYS_MALLOC_F is defined. 2512 2513 CONFIG_SYS_SPL_MALLOC_SIZE 2514 The size of the malloc pool used in SPL. 2515 2516 CONFIG_SPL_OS_BOOT 2517 Enable booting directly to an OS from SPL. 2518 See also: doc/README.falcon 2519 2520 CONFIG_SPL_DISPLAY_PRINT 2521 For ARM, enable an optional function to print more information 2522 about the running system. 2523 2524 CONFIG_SPL_INIT_MINIMAL 2525 Arch init code should be built for a very small image 2526 2527 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2528 Partition on the MMC to load U-Boot from when the MMC is being 2529 used in raw mode 2530 2531 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2532 Sector to load kernel uImage from when MMC is being 2533 used in raw mode (for Falcon mode) 2534 2535 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2536 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2537 Sector and number of sectors to load kernel argument 2538 parameters from when MMC is being used in raw mode 2539 (for falcon mode) 2540 2541 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 2542 Partition on the MMC to load U-Boot from when the MMC is being 2543 used in fs mode 2544 2545 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2546 Filename to read to load U-Boot when reading from filesystem 2547 2548 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2549 Filename to read to load kernel uImage when reading 2550 from filesystem (for Falcon mode) 2551 2552 CONFIG_SPL_FS_LOAD_ARGS_NAME 2553 Filename to read to load kernel argument parameters 2554 when reading from filesystem (for Falcon mode) 2555 2556 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2557 Set this for NAND SPL on PPC mpc83xx targets, so that 2558 start.S waits for the rest of the SPL to load before 2559 continuing (the hardware starts execution after just 2560 loading the first page rather than the full 4K). 2561 2562 CONFIG_SPL_SKIP_RELOCATE 2563 Avoid SPL relocation 2564 2565 CONFIG_SPL_NAND_BASE 2566 Include nand_base.c in the SPL. Requires 2567 CONFIG_SPL_NAND_DRIVERS. 2568 2569 CONFIG_SPL_NAND_DRIVERS 2570 SPL uses normal NAND drivers, not minimal drivers. 2571 2572 CONFIG_SPL_NAND_IDENT 2573 SPL uses the chip ID list to identify the NAND flash. 2574 Requires CONFIG_SPL_NAND_BASE. 2575 2576 CONFIG_SPL_NAND_ECC 2577 Include standard software ECC in the SPL 2578 2579 CONFIG_SPL_NAND_SIMPLE 2580 Support for NAND boot using simple NAND drivers that 2581 expose the cmd_ctrl() interface. 2582 2583 CONFIG_SPL_UBI 2584 Support for a lightweight UBI (fastmap) scanner and 2585 loader 2586 2587 CONFIG_SPL_NAND_RAW_ONLY 2588 Support to boot only raw u-boot.bin images. Use this only 2589 if you need to save space. 2590 2591 CONFIG_SPL_COMMON_INIT_DDR 2592 Set for common ddr init with serial presence detect in 2593 SPL binary. 2594 2595 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2596 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2597 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2598 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2599 CONFIG_SYS_NAND_ECCBYTES 2600 Defines the size and behavior of the NAND that SPL uses 2601 to read U-Boot 2602 2603 CONFIG_SPL_NAND_BOOT 2604 Add support NAND boot 2605 2606 CONFIG_SYS_NAND_U_BOOT_OFFS 2607 Location in NAND to read U-Boot from 2608 2609 CONFIG_SYS_NAND_U_BOOT_DST 2610 Location in memory to load U-Boot to 2611 2612 CONFIG_SYS_NAND_U_BOOT_SIZE 2613 Size of image to load 2614 2615 CONFIG_SYS_NAND_U_BOOT_START 2616 Entry point in loaded image to jump to 2617 2618 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2619 Define this if you need to first read the OOB and then the 2620 data. This is used, for example, on davinci platforms. 2621 2622 CONFIG_SPL_RAM_DEVICE 2623 Support for running image already present in ram, in SPL binary 2624 2625 CONFIG_SPL_PAD_TO 2626 Image offset to which the SPL should be padded before appending 2627 the SPL payload. By default, this is defined as 2628 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2629 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2630 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2631 2632 CONFIG_SPL_TARGET 2633 Final target image containing SPL and payload. Some SPLs 2634 use an arch-specific makefile fragment instead, for 2635 example if more than one image needs to be produced. 2636 2637 CONFIG_SPL_FIT_PRINT 2638 Printing information about a FIT image adds quite a bit of 2639 code to SPL. So this is normally disabled in SPL. Use this 2640 option to re-enable it. This will affect the output of the 2641 bootm command when booting a FIT image. 2642 2643- TPL framework 2644 CONFIG_TPL 2645 Enable building of TPL globally. 2646 2647 CONFIG_TPL_PAD_TO 2648 Image offset to which the TPL should be padded before appending 2649 the TPL payload. By default, this is defined as 2650 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2651 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2652 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2653 2654- Interrupt support (PPC): 2655 2656 There are common interrupt_init() and timer_interrupt() 2657 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2658 for CPU specific initialization. interrupt_init_cpu() 2659 should set decrementer_count to appropriate value. If 2660 CPU resets decrementer automatically after interrupt 2661 (ppc4xx) it should set decrementer_count to zero. 2662 timer_interrupt() calls timer_interrupt_cpu() for CPU 2663 specific handling. If board has watchdog / status_led 2664 / other_activity_monitor it works automatically from 2665 general timer_interrupt(). 2666 2667 2668Board initialization settings: 2669------------------------------ 2670 2671During Initialization u-boot calls a number of board specific functions 2672to allow the preparation of board specific prerequisites, e.g. pin setup 2673before drivers are initialized. To enable these callbacks the 2674following configuration macros have to be defined. Currently this is 2675architecture specific, so please check arch/your_architecture/lib/board.c 2676typically in board_init_f() and board_init_r(). 2677 2678- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2679- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2680- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2681- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2682 2683Configuration Settings: 2684----------------------- 2685 2686- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2687 Optionally it can be defined to support 64-bit memory commands. 2688 2689- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2690 undefine this when you're short of memory. 2691 2692- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2693 width of the commands listed in the 'help' command output. 2694 2695- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2696 prompt for user input. 2697 2698- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2699 2700- CONFIG_SYS_PBSIZE: Buffer size for Console output 2701 2702- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2703 2704- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2705 the application (usually a Linux kernel) when it is 2706 booted 2707 2708- CONFIG_SYS_BAUDRATE_TABLE: 2709 List of legal baudrate settings for this board. 2710 2711- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END: 2712 Begin and End addresses of the area used by the 2713 simple memory test. 2714 2715- CONFIG_SYS_MEMTEST_SCRATCH: 2716 Scratch address used by the alternate memory test 2717 You only need to set this if address zero isn't writeable 2718 2719- CONFIG_SYS_MEM_RESERVE_SECURE 2720 Only implemented for ARMv8 for now. 2721 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2722 is substracted from total RAM and won't be reported to OS. 2723 This memory can be used as secure memory. A variable 2724 gd->arch.secure_ram is used to track the location. In systems 2725 the RAM base is not zero, or RAM is divided into banks, 2726 this variable needs to be recalcuated to get the address. 2727 2728- CONFIG_SYS_MEM_TOP_HIDE: 2729 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2730 this specified memory area will get subtracted from the top 2731 (end) of RAM and won't get "touched" at all by U-Boot. By 2732 fixing up gd->ram_size the Linux kernel should gets passed 2733 the now "corrected" memory size and won't touch it either. 2734 This should work for arch/ppc and arch/powerpc. Only Linux 2735 board ports in arch/powerpc with bootwrapper support that 2736 recalculate the memory size from the SDRAM controller setup 2737 will have to get fixed in Linux additionally. 2738 2739 This option can be used as a workaround for the 440EPx/GRx 2740 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2741 be touched. 2742 2743 WARNING: Please make sure that this value is a multiple of 2744 the Linux page size (normally 4k). If this is not the case, 2745 then the end address of the Linux memory will be located at a 2746 non page size aligned address and this could cause major 2747 problems. 2748 2749- CONFIG_SYS_LOADS_BAUD_CHANGE: 2750 Enable temporary baudrate change while serial download 2751 2752- CONFIG_SYS_SDRAM_BASE: 2753 Physical start address of SDRAM. _Must_ be 0 here. 2754 2755- CONFIG_SYS_FLASH_BASE: 2756 Physical start address of Flash memory. 2757 2758- CONFIG_SYS_MONITOR_BASE: 2759 Physical start address of boot monitor code (set by 2760 make config files to be same as the text base address 2761 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2762 CONFIG_SYS_FLASH_BASE when booting from flash. 2763 2764- CONFIG_SYS_MONITOR_LEN: 2765 Size of memory reserved for monitor code, used to 2766 determine _at_compile_time_ (!) if the environment is 2767 embedded within the U-Boot image, or in a separate 2768 flash sector. 2769 2770- CONFIG_SYS_MALLOC_LEN: 2771 Size of DRAM reserved for malloc() use. 2772 2773- CONFIG_SYS_MALLOC_F_LEN 2774 Size of the malloc() pool for use before relocation. If 2775 this is defined, then a very simple malloc() implementation 2776 will become available before relocation. The address is just 2777 below the global data, and the stack is moved down to make 2778 space. 2779 2780 This feature allocates regions with increasing addresses 2781 within the region. calloc() is supported, but realloc() 2782 is not available. free() is supported but does nothing. 2783 The memory will be freed (or in fact just forgotten) when 2784 U-Boot relocates itself. 2785 2786- CONFIG_SYS_MALLOC_SIMPLE 2787 Provides a simple and small malloc() and calloc() for those 2788 boards which do not use the full malloc in SPL (which is 2789 enabled with CONFIG_SYS_SPL_MALLOC_START). 2790 2791- CONFIG_SYS_NONCACHED_MEMORY: 2792 Size of non-cached memory area. This area of memory will be 2793 typically located right below the malloc() area and mapped 2794 uncached in the MMU. This is useful for drivers that would 2795 otherwise require a lot of explicit cache maintenance. For 2796 some drivers it's also impossible to properly maintain the 2797 cache. For example if the regions that need to be flushed 2798 are not a multiple of the cache-line size, *and* padding 2799 cannot be allocated between the regions to align them (i.e. 2800 if the HW requires a contiguous array of regions, and the 2801 size of each region is not cache-aligned), then a flush of 2802 one region may result in overwriting data that hardware has 2803 written to another region in the same cache-line. This can 2804 happen for example in network drivers where descriptors for 2805 buffers are typically smaller than the CPU cache-line (e.g. 2806 16 bytes vs. 32 or 64 bytes). 2807 2808 Non-cached memory is only supported on 32-bit ARM at present. 2809 2810- CONFIG_SYS_BOOTM_LEN: 2811 Normally compressed uImages are limited to an 2812 uncompressed size of 8 MBytes. If this is not enough, 2813 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2814 to adjust this setting to your needs. 2815 2816- CONFIG_SYS_BOOTMAPSZ: 2817 Maximum size of memory mapped by the startup code of 2818 the Linux kernel; all data that must be processed by 2819 the Linux kernel (bd_info, boot arguments, FDT blob if 2820 used) must be put below this limit, unless "bootm_low" 2821 environment variable is defined and non-zero. In such case 2822 all data for the Linux kernel must be between "bootm_low" 2823 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2824 variable "bootm_mapsize" will override the value of 2825 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2826 then the value in "bootm_size" will be used instead. 2827 2828- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2829 Enable initrd_high functionality. If defined then the 2830 initrd_high feature is enabled and the bootm ramdisk subcommand 2831 is enabled. 2832 2833- CONFIG_SYS_BOOT_GET_CMDLINE: 2834 Enables allocating and saving kernel cmdline in space between 2835 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2836 2837- CONFIG_SYS_BOOT_GET_KBD: 2838 Enables allocating and saving a kernel copy of the bd_info in 2839 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2840 2841- CONFIG_SYS_MAX_FLASH_BANKS: 2842 Max number of Flash memory banks 2843 2844- CONFIG_SYS_MAX_FLASH_SECT: 2845 Max number of sectors on a Flash chip 2846 2847- CONFIG_SYS_FLASH_ERASE_TOUT: 2848 Timeout for Flash erase operations (in ms) 2849 2850- CONFIG_SYS_FLASH_WRITE_TOUT: 2851 Timeout for Flash write operations (in ms) 2852 2853- CONFIG_SYS_FLASH_LOCK_TOUT 2854 Timeout for Flash set sector lock bit operation (in ms) 2855 2856- CONFIG_SYS_FLASH_UNLOCK_TOUT 2857 Timeout for Flash clear lock bits operation (in ms) 2858 2859- CONFIG_SYS_FLASH_PROTECTION 2860 If defined, hardware flash sectors protection is used 2861 instead of U-Boot software protection. 2862 2863- CONFIG_SYS_DIRECT_FLASH_TFTP: 2864 2865 Enable TFTP transfers directly to flash memory; 2866 without this option such a download has to be 2867 performed in two steps: (1) download to RAM, and (2) 2868 copy from RAM to flash. 2869 2870 The two-step approach is usually more reliable, since 2871 you can check if the download worked before you erase 2872 the flash, but in some situations (when system RAM is 2873 too limited to allow for a temporary copy of the 2874 downloaded image) this option may be very useful. 2875 2876- CONFIG_SYS_FLASH_CFI: 2877 Define if the flash driver uses extra elements in the 2878 common flash structure for storing flash geometry. 2879 2880- CONFIG_FLASH_CFI_DRIVER 2881 This option also enables the building of the cfi_flash driver 2882 in the drivers directory 2883 2884- CONFIG_FLASH_CFI_MTD 2885 This option enables the building of the cfi_mtd driver 2886 in the drivers directory. The driver exports CFI flash 2887 to the MTD layer. 2888 2889- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2890 Use buffered writes to flash. 2891 2892- CONFIG_FLASH_SPANSION_S29WS_N 2893 s29ws-n MirrorBit flash has non-standard addresses for buffered 2894 write commands. 2895 2896- CONFIG_SYS_FLASH_QUIET_TEST 2897 If this option is defined, the common CFI flash doesn't 2898 print it's warning upon not recognized FLASH banks. This 2899 is useful, if some of the configured banks are only 2900 optionally available. 2901 2902- CONFIG_FLASH_SHOW_PROGRESS 2903 If defined (must be an integer), print out countdown 2904 digits and dots. Recommended value: 45 (9..1) for 80 2905 column displays, 15 (3..1) for 40 column displays. 2906 2907- CONFIG_FLASH_VERIFY 2908 If defined, the content of the flash (destination) is compared 2909 against the source after the write operation. An error message 2910 will be printed when the contents are not identical. 2911 Please note that this option is useless in nearly all cases, 2912 since such flash programming errors usually are detected earlier 2913 while unprotecting/erasing/programming. Please only enable 2914 this option if you really know what you are doing. 2915 2916- CONFIG_SYS_RX_ETH_BUFFER: 2917 Defines the number of Ethernet receive buffers. On some 2918 Ethernet controllers it is recommended to set this value 2919 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2920 buffers can be full shortly after enabling the interface 2921 on high Ethernet traffic. 2922 Defaults to 4 if not defined. 2923 2924- CONFIG_ENV_MAX_ENTRIES 2925 2926 Maximum number of entries in the hash table that is used 2927 internally to store the environment settings. The default 2928 setting is supposed to be generous and should work in most 2929 cases. This setting can be used to tune behaviour; see 2930 lib/hashtable.c for details. 2931 2932- CONFIG_ENV_FLAGS_LIST_DEFAULT 2933- CONFIG_ENV_FLAGS_LIST_STATIC 2934 Enable validation of the values given to environment variables when 2935 calling env set. Variables can be restricted to only decimal, 2936 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2937 the variables can also be restricted to IP address or MAC address. 2938 2939 The format of the list is: 2940 type_attribute = [s|d|x|b|i|m] 2941 access_attribute = [a|r|o|c] 2942 attributes = type_attribute[access_attribute] 2943 entry = variable_name[:attributes] 2944 list = entry[,list] 2945 2946 The type attributes are: 2947 s - String (default) 2948 d - Decimal 2949 x - Hexadecimal 2950 b - Boolean ([1yYtT|0nNfF]) 2951 i - IP address 2952 m - MAC address 2953 2954 The access attributes are: 2955 a - Any (default) 2956 r - Read-only 2957 o - Write-once 2958 c - Change-default 2959 2960 - CONFIG_ENV_FLAGS_LIST_DEFAULT 2961 Define this to a list (string) to define the ".flags" 2962 environment variable in the default or embedded environment. 2963 2964 - CONFIG_ENV_FLAGS_LIST_STATIC 2965 Define this to a list (string) to define validation that 2966 should be done if an entry is not found in the ".flags" 2967 environment variable. To override a setting in the static 2968 list, simply add an entry for the same variable name to the 2969 ".flags" variable. 2970 2971 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 2972 regular expression. This allows multiple variables to define the same 2973 flags without explicitly listing them for each variable. 2974 2975- CONFIG_ENV_ACCESS_IGNORE_FORCE 2976 If defined, don't allow the -f switch to env set override variable 2977 access flags. 2978 2979The following definitions that deal with the placement and management 2980of environment data (variable area); in general, we support the 2981following configurations: 2982 2983- CONFIG_BUILD_ENVCRC: 2984 2985 Builds up envcrc with the target environment so that external utils 2986 may easily extract it and embed it in final U-Boot images. 2987 2988BE CAREFUL! The first access to the environment happens quite early 2989in U-Boot initialization (when we try to get the setting of for the 2990console baudrate). You *MUST* have mapped your NVRAM area then, or 2991U-Boot will hang. 2992 2993Please note that even with NVRAM we still use a copy of the 2994environment in RAM: we could work on NVRAM directly, but we want to 2995keep settings there always unmodified except somebody uses "saveenv" 2996to save the current settings. 2997 2998BE CAREFUL! For some special cases, the local device can not use 2999"saveenv" command. For example, the local device will get the 3000environment stored in a remote NOR flash by SRIO or PCIE link, 3001but it can not erase, write this NOR flash by SRIO or PCIE interface. 3002 3003- CONFIG_NAND_ENV_DST 3004 3005 Defines address in RAM to which the nand_spl code should copy the 3006 environment. If redundant environment is used, it will be copied to 3007 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 3008 3009Please note that the environment is read-only until the monitor 3010has been relocated to RAM and a RAM copy of the environment has been 3011created; also, when using EEPROM you will have to use env_get_f() 3012until then to read environment variables. 3013 3014The environment is protected by a CRC32 checksum. Before the monitor 3015is relocated into RAM, as a result of a bad CRC you will be working 3016with the compiled-in default environment - *silently*!!! [This is 3017necessary, because the first environment variable we need is the 3018"baudrate" setting for the console - if we have a bad CRC, we don't 3019have any device yet where we could complain.] 3020 3021Note: once the monitor has been relocated, then it will complain if 3022the default environment is used; a new CRC is computed as soon as you 3023use the "saveenv" command to store a valid environment. 3024 3025- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 3026 Echo the inverted Ethernet link state to the fault LED. 3027 3028 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 3029 also needs to be defined. 3030 3031- CONFIG_SYS_FAULT_MII_ADDR: 3032 MII address of the PHY to check for the Ethernet link state. 3033 3034- CONFIG_NS16550_MIN_FUNCTIONS: 3035 Define this if you desire to only have use of the NS16550_init 3036 and NS16550_putc functions for the serial driver located at 3037 drivers/serial/ns16550.c. This option is useful for saving 3038 space for already greatly restricted images, including but not 3039 limited to NAND_SPL configurations. 3040 3041- CONFIG_DISPLAY_BOARDINFO 3042 Display information about the board that U-Boot is running on 3043 when U-Boot starts up. The board function checkboard() is called 3044 to do this. 3045 3046- CONFIG_DISPLAY_BOARDINFO_LATE 3047 Similar to the previous option, but display this information 3048 later, once stdio is running and output goes to the LCD, if 3049 present. 3050 3051- CONFIG_BOARD_SIZE_LIMIT: 3052 Maximum size of the U-Boot image. When defined, the 3053 build system checks that the actual size does not 3054 exceed it. 3055 3056Low Level (hardware related) configuration options: 3057--------------------------------------------------- 3058 3059- CONFIG_SYS_CACHELINE_SIZE: 3060 Cache Line Size of the CPU. 3061 3062- CONFIG_SYS_CCSRBAR_DEFAULT: 3063 Default (power-on reset) physical address of CCSR on Freescale 3064 PowerPC SOCs. 3065 3066- CONFIG_SYS_CCSRBAR: 3067 Virtual address of CCSR. On a 32-bit build, this is typically 3068 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 3069 3070- CONFIG_SYS_CCSRBAR_PHYS: 3071 Physical address of CCSR. CCSR can be relocated to a new 3072 physical address, if desired. In this case, this macro should 3073 be set to that address. Otherwise, it should be set to the 3074 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 3075 is typically relocated on 36-bit builds. It is recommended 3076 that this macro be defined via the _HIGH and _LOW macros: 3077 3078 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 3079 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 3080 3081- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 3082 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 3083 either 0 (32-bit build) or 0xF (36-bit build). This macro is 3084 used in assembly code, so it must not contain typecasts or 3085 integer size suffixes (e.g. "ULL"). 3086 3087- CONFIG_SYS_CCSRBAR_PHYS_LOW: 3088 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 3089 used in assembly code, so it must not contain typecasts or 3090 integer size suffixes (e.g. "ULL"). 3091 3092- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 3093 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 3094 forced to a value that ensures that CCSR is not relocated. 3095 3096- Floppy Disk Support: 3097 CONFIG_SYS_FDC_DRIVE_NUMBER 3098 3099 the default drive number (default value 0) 3100 3101 CONFIG_SYS_ISA_IO_STRIDE 3102 3103 defines the spacing between FDC chipset registers 3104 (default value 1) 3105 3106 CONFIG_SYS_ISA_IO_OFFSET 3107 3108 defines the offset of register from address. It 3109 depends on which part of the data bus is connected to 3110 the FDC chipset. (default value 0) 3111 3112 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and 3113 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their 3114 default value. 3115 3116 if CONFIG_SYS_FDC_HW_INIT is defined, then the function 3117 fdc_hw_init() is called at the beginning of the FDC 3118 setup. fdc_hw_init() must be provided by the board 3119 source code. It is used to make hardware-dependent 3120 initializations. 3121 3122- CONFIG_IDE_AHB: 3123 Most IDE controllers were designed to be connected with PCI 3124 interface. Only few of them were designed for AHB interface. 3125 When software is doing ATA command and data transfer to 3126 IDE devices through IDE-AHB controller, some additional 3127 registers accessing to these kind of IDE-AHB controller 3128 is required. 3129 3130- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 3131 DO NOT CHANGE unless you know exactly what you're 3132 doing! (11-4) [MPC8xx systems only] 3133 3134- CONFIG_SYS_INIT_RAM_ADDR: 3135 3136 Start address of memory area that can be used for 3137 initial data and stack; please note that this must be 3138 writable memory that is working WITHOUT special 3139 initialization, i. e. you CANNOT use normal RAM which 3140 will become available only after programming the 3141 memory controller and running certain initialization 3142 sequences. 3143 3144 U-Boot uses the following memory types: 3145 - MPC8xx: IMMR (internal memory of the CPU) 3146 3147- CONFIG_SYS_GBL_DATA_OFFSET: 3148 3149 Offset of the initial data structure in the memory 3150 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 3151 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 3152 data is located at the end of the available space 3153 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 3154 GENERATED_GBL_DATA_SIZE), and the initial stack is just 3155 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 3156 CONFIG_SYS_GBL_DATA_OFFSET) downward. 3157 3158 Note: 3159 On the MPC824X (or other systems that use the data 3160 cache for initial memory) the address chosen for 3161 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 3162 point to an otherwise UNUSED address space between 3163 the top of RAM and the start of the PCI space. 3164 3165- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 3166 3167- CONFIG_SYS_OR_TIMING_SDRAM: 3168 SDRAM timing 3169 3170- CONFIG_SYS_MAMR_PTA: 3171 periodic timer for refresh 3172 3173- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 3174 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 3175 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 3176 CONFIG_SYS_BR1_PRELIM: 3177 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 3178 3179- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 3180 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 3181 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 3182 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 3183 3184- CONFIG_PCI_ENUM_ONLY 3185 Only scan through and get the devices on the buses. 3186 Don't do any setup work, presumably because someone or 3187 something has already done it, and we don't need to do it 3188 a second time. Useful for platforms that are pre-booted 3189 by coreboot or similar. 3190 3191- CONFIG_PCI_INDIRECT_BRIDGE: 3192 Enable support for indirect PCI bridges. 3193 3194- CONFIG_SYS_SRIO: 3195 Chip has SRIO or not 3196 3197- CONFIG_SRIO1: 3198 Board has SRIO 1 port available 3199 3200- CONFIG_SRIO2: 3201 Board has SRIO 2 port available 3202 3203- CONFIG_SRIO_PCIE_BOOT_MASTER 3204 Board can support master function for Boot from SRIO and PCIE 3205 3206- CONFIG_SYS_SRIOn_MEM_VIRT: 3207 Virtual Address of SRIO port 'n' memory region 3208 3209- CONFIG_SYS_SRIOn_MEM_PHYS: 3210 Physical Address of SRIO port 'n' memory region 3211 3212- CONFIG_SYS_SRIOn_MEM_SIZE: 3213 Size of SRIO port 'n' memory region 3214 3215- CONFIG_SYS_NAND_BUSWIDTH_16BIT 3216 Defined to tell the NAND controller that the NAND chip is using 3217 a 16 bit bus. 3218 Not all NAND drivers use this symbol. 3219 Example of drivers that use it: 3220 - drivers/mtd/nand/raw/ndfc.c 3221 - drivers/mtd/nand/raw/mxc_nand.c 3222 3223- CONFIG_SYS_NDFC_EBC0_CFG 3224 Sets the EBC0_CFG register for the NDFC. If not defined 3225 a default value will be used. 3226 3227- CONFIG_SPD_EEPROM 3228 Get DDR timing information from an I2C EEPROM. Common 3229 with pluggable memory modules such as SODIMMs 3230 3231 SPD_EEPROM_ADDRESS 3232 I2C address of the SPD EEPROM 3233 3234- CONFIG_SYS_SPD_BUS_NUM 3235 If SPD EEPROM is on an I2C bus other than the first 3236 one, specify here. Note that the value must resolve 3237 to something your driver can deal with. 3238 3239- CONFIG_SYS_DDR_RAW_TIMING 3240 Get DDR timing information from other than SPD. Common with 3241 soldered DDR chips onboard without SPD. DDR raw timing 3242 parameters are extracted from datasheet and hard-coded into 3243 header files or board specific files. 3244 3245- CONFIG_FSL_DDR_INTERACTIVE 3246 Enable interactive DDR debugging. See doc/README.fsl-ddr. 3247 3248- CONFIG_FSL_DDR_SYNC_REFRESH 3249 Enable sync of refresh for multiple controllers. 3250 3251- CONFIG_FSL_DDR_BIST 3252 Enable built-in memory test for Freescale DDR controllers. 3253 3254- CONFIG_SYS_83XX_DDR_USES_CS0 3255 Only for 83xx systems. If specified, then DDR should 3256 be configured using CS0 and CS1 instead of CS2 and CS3. 3257 3258- CONFIG_RMII 3259 Enable RMII mode for all FECs. 3260 Note that this is a global option, we can't 3261 have one FEC in standard MII mode and another in RMII mode. 3262 3263- CONFIG_CRC32_VERIFY 3264 Add a verify option to the crc32 command. 3265 The syntax is: 3266 3267 => crc32 -v <address> <count> <crc32> 3268 3269 Where address/count indicate a memory area 3270 and crc32 is the correct crc32 which the 3271 area should have. 3272 3273- CONFIG_LOOPW 3274 Add the "loopw" memory command. This only takes effect if 3275 the memory commands are activated globally (CONFIG_CMD_MEMORY). 3276 3277- CONFIG_MX_CYCLIC 3278 Add the "mdc" and "mwc" memory commands. These are cyclic 3279 "md/mw" commands. 3280 Examples: 3281 3282 => mdc.b 10 4 500 3283 This command will print 4 bytes (10,11,12,13) each 500 ms. 3284 3285 => mwc.l 100 12345678 10 3286 This command will write 12345678 to address 100 all 10 ms. 3287 3288 This only takes effect if the memory commands are activated 3289 globally (CONFIG_CMD_MEMORY). 3290 3291- CONFIG_SKIP_LOWLEVEL_INIT 3292 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 3293 low level initializations (like setting up the memory 3294 controller) are omitted and/or U-Boot does not 3295 relocate itself into RAM. 3296 3297 Normally this variable MUST NOT be defined. The only 3298 exception is when U-Boot is loaded (to RAM) by some 3299 other boot loader or by a debugger which performs 3300 these initializations itself. 3301 3302- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 3303 [ARM926EJ-S only] This allows just the call to lowlevel_init() 3304 to be skipped. The normal CP15 init (such as enabling the 3305 instruction cache) is still performed. 3306 3307- CONFIG_SPL_BUILD 3308 Modifies the behaviour of start.S when compiling a loader 3309 that is executed before the actual U-Boot. E.g. when 3310 compiling a NAND SPL. 3311 3312- CONFIG_TPL_BUILD 3313 Modifies the behaviour of start.S when compiling a loader 3314 that is executed after the SPL and before the actual U-Boot. 3315 It is loaded by the SPL. 3316 3317- CONFIG_SYS_MPC85XX_NO_RESETVEC 3318 Only for 85xx systems. If this variable is specified, the section 3319 .resetvec is not kept and the section .bootpg is placed in the 3320 previous 4k of the .text section. 3321 3322- CONFIG_ARCH_MAP_SYSMEM 3323 Generally U-Boot (and in particular the md command) uses 3324 effective address. It is therefore not necessary to regard 3325 U-Boot address as virtual addresses that need to be translated 3326 to physical addresses. However, sandbox requires this, since 3327 it maintains its own little RAM buffer which contains all 3328 addressable memory. This option causes some memory accesses 3329 to be mapped through map_sysmem() / unmap_sysmem(). 3330 3331- CONFIG_X86_RESET_VECTOR 3332 If defined, the x86 reset vector code is included. This is not 3333 needed when U-Boot is running from Coreboot. 3334 3335- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 3336 Option to disable subpage write in NAND driver 3337 driver that uses this: 3338 drivers/mtd/nand/raw/davinci_nand.c 3339 3340Freescale QE/FMAN Firmware Support: 3341----------------------------------- 3342 3343The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 3344loading of "firmware", which is encoded in the QE firmware binary format. 3345This firmware often needs to be loaded during U-Boot booting, so macros 3346are used to identify the storage device (NOR flash, SPI, etc) and the address 3347within that device. 3348 3349- CONFIG_SYS_FMAN_FW_ADDR 3350 The address in the storage device where the FMAN microcode is located. The 3351 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3352 is also specified. 3353 3354- CONFIG_SYS_QE_FW_ADDR 3355 The address in the storage device where the QE microcode is located. The 3356 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro 3357 is also specified. 3358 3359- CONFIG_SYS_QE_FMAN_FW_LENGTH 3360 The maximum possible size of the firmware. The firmware binary format 3361 has a field that specifies the actual size of the firmware, but it 3362 might not be possible to read any part of the firmware unless some 3363 local storage is allocated to hold the entire firmware first. 3364 3365- CONFIG_SYS_QE_FMAN_FW_IN_NOR 3366 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 3367 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 3368 virtual address in NOR flash. 3369 3370- CONFIG_SYS_QE_FMAN_FW_IN_NAND 3371 Specifies that QE/FMAN firmware is located in NAND flash. 3372 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 3373 3374- CONFIG_SYS_QE_FMAN_FW_IN_MMC 3375 Specifies that QE/FMAN firmware is located on the primary SD/MMC 3376 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 3377 3378- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 3379 Specifies that QE/FMAN firmware is located in the remote (master) 3380 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 3381 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 3382 window->master inbound window->master LAW->the ucode address in 3383 master's memory space. 3384 3385Freescale Layerscape Management Complex Firmware Support: 3386--------------------------------------------------------- 3387The Freescale Layerscape Management Complex (MC) supports the loading of 3388"firmware". 3389This firmware often needs to be loaded during U-Boot booting, so macros 3390are used to identify the storage device (NOR flash, SPI, etc) and the address 3391within that device. 3392 3393- CONFIG_FSL_MC_ENET 3394 Enable the MC driver for Layerscape SoCs. 3395 3396Freescale Layerscape Debug Server Support: 3397------------------------------------------- 3398The Freescale Layerscape Debug Server Support supports the loading of 3399"Debug Server firmware" and triggering SP boot-rom. 3400This firmware often needs to be loaded during U-Boot booting. 3401 3402- CONFIG_SYS_MC_RSV_MEM_ALIGN 3403 Define alignment of reserved memory MC requires 3404 3405Reproducible builds 3406------------------- 3407 3408In order to achieve reproducible builds, timestamps used in the U-Boot build 3409process have to be set to a fixed value. 3410 3411This is done using the SOURCE_DATE_EPOCH environment variable. 3412SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3413option for U-Boot or an environment variable in U-Boot. 3414 3415SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3416 3417Building the Software: 3418====================== 3419 3420Building U-Boot has been tested in several native build environments 3421and in many different cross environments. Of course we cannot support 3422all possibly existing versions of cross development tools in all 3423(potentially obsolete) versions. In case of tool chain problems we 3424recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) 3425which is extensively used to build and test U-Boot. 3426 3427If you are not using a native environment, it is assumed that you 3428have GNU cross compiling tools available in your path. In this case, 3429you must set the environment variable CROSS_COMPILE in your shell. 3430Note that no changes to the Makefile or any other source files are 3431necessary. For example using the ELDK on a 4xx CPU, please enter: 3432 3433 $ CROSS_COMPILE=ppc_4xx- 3434 $ export CROSS_COMPILE 3435 3436Note: If you wish to generate Windows versions of the utilities in 3437 the tools directory you can use the MinGW toolchain 3438 (http://www.mingw.org). Set your HOST tools to the MinGW 3439 toolchain and execute 'make tools'. For example: 3440 3441 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools 3442 3443 Binaries such as tools/mkimage.exe will be created which can 3444 be executed on computers running Windows. 3445 3446U-Boot is intended to be simple to build. After installing the 3447sources you must configure U-Boot for one specific board type. This 3448is done by typing: 3449 3450 make NAME_defconfig 3451 3452where "NAME_defconfig" is the name of one of the existing configu- 3453rations; see boards.cfg for supported names. 3454 3455Note: for some board special configuration names may exist; check if 3456 additional information is available from the board vendor; for 3457 instance, the TQM823L systems are available without (standard) 3458 or with LCD support. You can select such additional "features" 3459 when choosing the configuration, i. e. 3460 3461 make TQM823L_defconfig 3462 - will configure for a plain TQM823L, i. e. no LCD support 3463 3464 make TQM823L_LCD_defconfig 3465 - will configure for a TQM823L with U-Boot console on LCD 3466 3467 etc. 3468 3469 3470Finally, type "make all", and you should get some working U-Boot 3471images ready for download to / installation on your system: 3472 3473- "u-boot.bin" is a raw binary image 3474- "u-boot" is an image in ELF binary format 3475- "u-boot.srec" is in Motorola S-Record format 3476 3477By default the build is performed locally and the objects are saved 3478in the source directory. One of the two methods can be used to change 3479this behavior and build U-Boot to some external directory: 3480 34811. Add O= to the make command line invocations: 3482 3483 make O=/tmp/build distclean 3484 make O=/tmp/build NAME_defconfig 3485 make O=/tmp/build all 3486 34872. Set environment variable KBUILD_OUTPUT to point to the desired location: 3488 3489 export KBUILD_OUTPUT=/tmp/build 3490 make distclean 3491 make NAME_defconfig 3492 make all 3493 3494Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3495variable. 3496 3497User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3498setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3499For example to treat all compiler warnings as errors: 3500 3501 make KCFLAGS=-Werror 3502 3503Please be aware that the Makefiles assume you are using GNU make, so 3504for instance on NetBSD you might need to use "gmake" instead of 3505native "make". 3506 3507 3508If the system board that you have is not listed, then you will need 3509to port U-Boot to your hardware platform. To do this, follow these 3510steps: 3511 35121. Create a new directory to hold your board specific code. Add any 3513 files you need. In your board directory, you will need at least 3514 the "Makefile" and a "<board>.c". 35152. Create a new configuration file "include/configs/<board>.h" for 3516 your board. 35173. If you're porting U-Boot to a new CPU, then also create a new 3518 directory to hold your CPU specific code. Add any files you need. 35194. Run "make <board>_defconfig" with your new name. 35205. Type "make", and you should get a working "u-boot.srec" file 3521 to be installed on your target system. 35226. Debug and solve any problems that might arise. 3523 [Of course, this last step is much harder than it sounds.] 3524 3525 3526Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3527============================================================== 3528 3529If you have modified U-Boot sources (for instance added a new board 3530or support for new devices, a new CPU, etc.) you are expected to 3531provide feedback to the other developers. The feedback normally takes 3532the form of a "patch", i. e. a context diff against a certain (latest 3533official or latest in the git repository) version of U-Boot sources. 3534 3535But before you submit such a patch, please verify that your modifi- 3536cation did not break existing code. At least make sure that *ALL* of 3537the supported boards compile WITHOUT ANY compiler warnings. To do so, 3538just run the buildman script (tools/buildman/buildman), which will 3539configure and build U-Boot for ALL supported system. Be warned, this 3540will take a while. Please see the buildman README, or run 'buildman -H' 3541for documentation. 3542 3543 3544See also "U-Boot Porting Guide" below. 3545 3546 3547Monitor Commands - Overview: 3548============================ 3549 3550go - start application at address 'addr' 3551run - run commands in an environment variable 3552bootm - boot application image from memory 3553bootp - boot image via network using BootP/TFTP protocol 3554bootz - boot zImage from memory 3555tftpboot- boot image via network using TFTP protocol 3556 and env variables "ipaddr" and "serverip" 3557 (and eventually "gatewayip") 3558tftpput - upload a file via network using TFTP protocol 3559rarpboot- boot image via network using RARP/TFTP protocol 3560diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3561loads - load S-Record file over serial line 3562loadb - load binary file over serial line (kermit mode) 3563md - memory display 3564mm - memory modify (auto-incrementing) 3565nm - memory modify (constant address) 3566mw - memory write (fill) 3567cp - memory copy 3568cmp - memory compare 3569crc32 - checksum calculation 3570i2c - I2C sub-system 3571sspi - SPI utility commands 3572base - print or set address offset 3573printenv- print environment variables 3574setenv - set environment variables 3575saveenv - save environment variables to persistent storage 3576protect - enable or disable FLASH write protection 3577erase - erase FLASH memory 3578flinfo - print FLASH memory information 3579nand - NAND memory operations (see doc/README.nand) 3580bdinfo - print Board Info structure 3581iminfo - print header information for application image 3582coninfo - print console devices and informations 3583ide - IDE sub-system 3584loop - infinite loop on address range 3585loopw - infinite write loop on address range 3586mtest - simple RAM test 3587icache - enable or disable instruction cache 3588dcache - enable or disable data cache 3589reset - Perform RESET of the CPU 3590echo - echo args to console 3591version - print monitor version 3592help - print online help 3593? - alias for 'help' 3594 3595 3596Monitor Commands - Detailed Description: 3597======================================== 3598 3599TODO. 3600 3601For now: just type "help <command>". 3602 3603 3604Environment Variables: 3605====================== 3606 3607U-Boot supports user configuration using Environment Variables which 3608can be made persistent by saving to Flash memory. 3609 3610Environment Variables are set using "setenv", printed using 3611"printenv", and saved to Flash using "saveenv". Using "setenv" 3612without a value can be used to delete a variable from the 3613environment. As long as you don't save the environment you are 3614working with an in-memory copy. In case the Flash area containing the 3615environment is erased by accident, a default environment is provided. 3616 3617Some configuration options can be set using Environment Variables. 3618 3619List of environment variables (most likely not complete): 3620 3621 baudrate - see CONFIG_BAUDRATE 3622 3623 bootdelay - see CONFIG_BOOTDELAY 3624 3625 bootcmd - see CONFIG_BOOTCOMMAND 3626 3627 bootargs - Boot arguments when booting an RTOS image 3628 3629 bootfile - Name of the image to load with TFTP 3630 3631 bootm_low - Memory range available for image processing in the bootm 3632 command can be restricted. This variable is given as 3633 a hexadecimal number and defines lowest address allowed 3634 for use by the bootm command. See also "bootm_size" 3635 environment variable. Address defined by "bootm_low" is 3636 also the base of the initial memory mapping for the Linux 3637 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3638 bootm_mapsize. 3639 3640 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3641 This variable is given as a hexadecimal number and it 3642 defines the size of the memory region starting at base 3643 address bootm_low that is accessible by the Linux kernel 3644 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3645 as the default value if it is defined, and bootm_size is 3646 used otherwise. 3647 3648 bootm_size - Memory range available for image processing in the bootm 3649 command can be restricted. This variable is given as 3650 a hexadecimal number and defines the size of the region 3651 allowed for use by the bootm command. See also "bootm_low" 3652 environment variable. 3653 3654 updatefile - Location of the software update file on a TFTP server, used 3655 by the automatic software update feature. Please refer to 3656 documentation in doc/README.update for more details. 3657 3658 autoload - if set to "no" (any string beginning with 'n'), 3659 "bootp" will just load perform a lookup of the 3660 configuration from the BOOTP server, but not try to 3661 load any image using TFTP 3662 3663 autostart - if set to "yes", an image loaded using the "bootp", 3664 "rarpboot", "tftpboot" or "diskboot" commands will 3665 be automatically started (by internally calling 3666 "bootm") 3667 3668 If set to "no", a standalone image passed to the 3669 "bootm" command will be copied to the load address 3670 (and eventually uncompressed), but NOT be started. 3671 This can be used to load and uncompress arbitrary 3672 data. 3673 3674 fdt_high - if set this restricts the maximum address that the 3675 flattened device tree will be copied into upon boot. 3676 For example, if you have a system with 1 GB memory 3677 at physical address 0x10000000, while Linux kernel 3678 only recognizes the first 704 MB as low memory, you 3679 may need to set fdt_high as 0x3C000000 to have the 3680 device tree blob be copied to the maximum address 3681 of the 704 MB low memory, so that Linux kernel can 3682 access it during the boot procedure. 3683 3684 If this is set to the special value 0xFFFFFFFF then 3685 the fdt will not be copied at all on boot. For this 3686 to work it must reside in writable memory, have 3687 sufficient padding on the end of it for u-boot to 3688 add the information it needs into it, and the memory 3689 must be accessible by the kernel. 3690 3691 fdtcontroladdr- if set this is the address of the control flattened 3692 device tree used by U-Boot when CONFIG_OF_CONTROL is 3693 defined. 3694 3695 i2cfast - (PPC405GP|PPC405EP only) 3696 if set to 'y' configures Linux I2C driver for fast 3697 mode (400kHZ). This environment variable is used in 3698 initialization code. So, for changes to be effective 3699 it must be saved and board must be reset. 3700 3701 initrd_high - restrict positioning of initrd images: 3702 If this variable is not set, initrd images will be 3703 copied to the highest possible address in RAM; this 3704 is usually what you want since it allows for 3705 maximum initrd size. If for some reason you want to 3706 make sure that the initrd image is loaded below the 3707 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3708 variable to a value of "no" or "off" or "0". 3709 Alternatively, you can set it to a maximum upper 3710 address to use (U-Boot will still check that it 3711 does not overwrite the U-Boot stack and data). 3712 3713 For instance, when you have a system with 16 MB 3714 RAM, and want to reserve 4 MB from use by Linux, 3715 you can do this by adding "mem=12M" to the value of 3716 the "bootargs" variable. However, now you must make 3717 sure that the initrd image is placed in the first 3718 12 MB as well - this can be done with 3719 3720 setenv initrd_high 00c00000 3721 3722 If you set initrd_high to 0xFFFFFFFF, this is an 3723 indication to U-Boot that all addresses are legal 3724 for the Linux kernel, including addresses in flash 3725 memory. In this case U-Boot will NOT COPY the 3726 ramdisk at all. This may be useful to reduce the 3727 boot time on your system, but requires that this 3728 feature is supported by your Linux kernel. 3729 3730 ipaddr - IP address; needed for tftpboot command 3731 3732 loadaddr - Default load address for commands like "bootp", 3733 "rarpboot", "tftpboot", "loadb" or "diskboot" 3734 3735 loads_echo - see CONFIG_LOADS_ECHO 3736 3737 serverip - TFTP server IP address; needed for tftpboot command 3738 3739 bootretry - see CONFIG_BOOT_RETRY_TIME 3740 3741 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3742 3743 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3744 3745 ethprime - controls which interface is used first. 3746 3747 ethact - controls which interface is currently active. 3748 For example you can do the following 3749 3750 => setenv ethact FEC 3751 => ping 192.168.0.1 # traffic sent on FEC 3752 => setenv ethact SCC 3753 => ping 10.0.0.1 # traffic sent on SCC 3754 3755 ethrotate - When set to "no" U-Boot does not go through all 3756 available network interfaces. 3757 It just stays at the currently selected interface. 3758 3759 netretry - When set to "no" each network operation will 3760 either succeed or fail without retrying. 3761 When set to "once" the network operation will 3762 fail when all the available network interfaces 3763 are tried once without success. 3764 Useful on scripts which control the retry operation 3765 themselves. 3766 3767 npe_ucode - set load address for the NPE microcode 3768 3769 silent_linux - If set then Linux will be told to boot silently, by 3770 changing the console to be empty. If "yes" it will be 3771 made silent. If "no" it will not be made silent. If 3772 unset, then it will be made silent if the U-Boot console 3773 is silent. 3774 3775 tftpsrcp - If this is set, the value is used for TFTP's 3776 UDP source port. 3777 3778 tftpdstp - If this is set, the value is used for TFTP's UDP 3779 destination port instead of the Well Know Port 69. 3780 3781 tftpblocksize - Block size to use for TFTP transfers; if not set, 3782 we use the TFTP server's default block size 3783 3784 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3785 seconds, minimum value is 1000 = 1 second). Defines 3786 when a packet is considered to be lost so it has to 3787 be retransmitted. The default is 5000 = 5 seconds. 3788 Lowering this value may make downloads succeed 3789 faster in networks with high packet loss rates or 3790 with unreliable TFTP servers. 3791 3792 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3793 unit, minimum value = 0). Defines how many timeouts 3794 can happen during a single file transfer before that 3795 transfer is aborted. The default is 10, and 0 means 3796 'no timeouts allowed'. Increasing this value may help 3797 downloads succeed with high packet loss rates, or with 3798 unreliable TFTP servers or client hardware. 3799 3800 vlan - When set to a value < 4095 the traffic over 3801 Ethernet is encapsulated/received over 802.1q 3802 VLAN tagged frames. 3803 3804 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3805 Unsigned value, in milliseconds. If not set, the period will 3806 be either the default (28000), or a value based on 3807 CONFIG_NET_RETRY_COUNT, if defined. This value has 3808 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3809 3810The following image location variables contain the location of images 3811used in booting. The "Image" column gives the role of the image and is 3812not an environment variable name. The other columns are environment 3813variable names. "File Name" gives the name of the file on a TFTP 3814server, "RAM Address" gives the location in RAM the image will be 3815loaded to, and "Flash Location" gives the image's address in NOR 3816flash or offset in NAND flash. 3817 3818*Note* - these variables don't have to be defined for all boards, some 3819boards currently use other variables for these purposes, and some 3820boards use these variables for other purposes. 3821 3822Image File Name RAM Address Flash Location 3823----- --------- ----------- -------------- 3824u-boot u-boot u-boot_addr_r u-boot_addr 3825Linux kernel bootfile kernel_addr_r kernel_addr 3826device tree blob fdtfile fdt_addr_r fdt_addr 3827ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3828 3829The following environment variables may be used and automatically 3830updated by the network boot commands ("bootp" and "rarpboot"), 3831depending the information provided by your boot server: 3832 3833 bootfile - see above 3834 dnsip - IP address of your Domain Name Server 3835 dnsip2 - IP address of your secondary Domain Name Server 3836 gatewayip - IP address of the Gateway (Router) to use 3837 hostname - Target hostname 3838 ipaddr - see above 3839 netmask - Subnet Mask 3840 rootpath - Pathname of the root filesystem on the NFS server 3841 serverip - see above 3842 3843 3844There are two special Environment Variables: 3845 3846 serial# - contains hardware identification information such 3847 as type string and/or serial number 3848 ethaddr - Ethernet address 3849 3850These variables can be set only once (usually during manufacturing of 3851the board). U-Boot refuses to delete or overwrite these variables 3852once they have been set once. 3853 3854 3855Further special Environment Variables: 3856 3857 ver - Contains the U-Boot version string as printed 3858 with the "version" command. This variable is 3859 readonly (see CONFIG_VERSION_VARIABLE). 3860 3861 3862Please note that changes to some configuration parameters may take 3863only effect after the next boot (yes, that's just like Windoze :-). 3864 3865 3866Callback functions for environment variables: 3867--------------------------------------------- 3868 3869For some environment variables, the behavior of u-boot needs to change 3870when their values are changed. This functionality allows functions to 3871be associated with arbitrary variables. On creation, overwrite, or 3872deletion, the callback will provide the opportunity for some side 3873effect to happen or for the change to be rejected. 3874 3875The callbacks are named and associated with a function using the 3876U_BOOT_ENV_CALLBACK macro in your board or driver code. 3877 3878These callbacks are associated with variables in one of two ways. The 3879static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3880in the board configuration to a string that defines a list of 3881associations. The list must be in the following format: 3882 3883 entry = variable_name[:callback_name] 3884 list = entry[,list] 3885 3886If the callback name is not specified, then the callback is deleted. 3887Spaces are also allowed anywhere in the list. 3888 3889Callbacks can also be associated by defining the ".callbacks" variable 3890with the same list format above. Any association in ".callbacks" will 3891override any association in the static list. You can define 3892CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3893".callbacks" environment variable in the default or embedded environment. 3894 3895If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3896regular expression. This allows multiple variables to be connected to 3897the same callback without explicitly listing them all out. 3898 3899The signature of the callback functions is: 3900 3901 int callback(const char *name, const char *value, enum env_op op, int flags) 3902 3903* name - changed environment variable 3904* value - new value of the environment variable 3905* op - operation (create, overwrite, or delete) 3906* flags - attributes of the environment variable change, see flags H_* in 3907 include/search.h 3908 3909The return value is 0 if the variable change is accepted and 1 otherwise. 3910 3911Command Line Parsing: 3912===================== 3913 3914There are two different command line parsers available with U-Boot: 3915the old "simple" one, and the much more powerful "hush" shell: 3916 3917Old, simple command line parser: 3918-------------------------------- 3919 3920- supports environment variables (through setenv / saveenv commands) 3921- several commands on one line, separated by ';' 3922- variable substitution using "... ${name} ..." syntax 3923- special characters ('$', ';') can be escaped by prefixing with '\', 3924 for example: 3925 setenv bootcmd bootm \${address} 3926- You can also escape text by enclosing in single apostrophes, for example: 3927 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 3928 3929Hush shell: 3930----------- 3931 3932- similar to Bourne shell, with control structures like 3933 if...then...else...fi, for...do...done; while...do...done, 3934 until...do...done, ... 3935- supports environment ("global") variables (through setenv / saveenv 3936 commands) and local shell variables (through standard shell syntax 3937 "name=value"); only environment variables can be used with "run" 3938 command 3939 3940General rules: 3941-------------- 3942 3943(1) If a command line (or an environment variable executed by a "run" 3944 command) contains several commands separated by semicolon, and 3945 one of these commands fails, then the remaining commands will be 3946 executed anyway. 3947 3948(2) If you execute several variables with one call to run (i. e. 3949 calling run with a list of variables as arguments), any failing 3950 command will cause "run" to terminate, i. e. the remaining 3951 variables are not executed. 3952 3953Note for Redundant Ethernet Interfaces: 3954======================================= 3955 3956Some boards come with redundant Ethernet interfaces; U-Boot supports 3957such configurations and is capable of automatic selection of a 3958"working" interface when needed. MAC assignment works as follows: 3959 3960Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 3961MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 3962"eth1addr" (=>eth1), "eth2addr", ... 3963 3964If the network interface stores some valid MAC address (for instance 3965in SROM), this is used as default address if there is NO correspon- 3966ding setting in the environment; if the corresponding environment 3967variable is set, this overrides the settings in the card; that means: 3968 3969o If the SROM has a valid MAC address, and there is no address in the 3970 environment, the SROM's address is used. 3971 3972o If there is no valid address in the SROM, and a definition in the 3973 environment exists, then the value from the environment variable is 3974 used. 3975 3976o If both the SROM and the environment contain a MAC address, and 3977 both addresses are the same, this MAC address is used. 3978 3979o If both the SROM and the environment contain a MAC address, and the 3980 addresses differ, the value from the environment is used and a 3981 warning is printed. 3982 3983o If neither SROM nor the environment contain a MAC address, an error 3984 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 3985 a random, locally-assigned MAC is used. 3986 3987If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 3988will be programmed into hardware as part of the initialization process. This 3989may be skipped by setting the appropriate 'ethmacskip' environment variable. 3990The naming convention is as follows: 3991"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 3992 3993Image Formats: 3994============== 3995 3996U-Boot is capable of booting (and performing other auxiliary operations on) 3997images in two formats: 3998 3999New uImage format (FIT) 4000----------------------- 4001 4002Flexible and powerful format based on Flattened Image Tree -- FIT (similar 4003to Flattened Device Tree). It allows the use of images with multiple 4004components (several kernels, ramdisks, etc.), with contents protected by 4005SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 4006 4007 4008Old uImage format 4009----------------- 4010 4011Old image format is based on binary files which can be basically anything, 4012preceded by a special header; see the definitions in include/image.h for 4013details; basically, the header defines the following image properties: 4014 4015* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 4016 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 4017 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 4018 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 4019 INTEGRITY). 4020* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 4021 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 4022 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 4023* Compression Type (uncompressed, gzip, bzip2) 4024* Load Address 4025* Entry Point 4026* Image Name 4027* Image Timestamp 4028 4029The header is marked by a special Magic Number, and both the header 4030and the data portions of the image are secured against corruption by 4031CRC32 checksums. 4032 4033 4034Linux Support: 4035============== 4036 4037Although U-Boot should support any OS or standalone application 4038easily, the main focus has always been on Linux during the design of 4039U-Boot. 4040 4041U-Boot includes many features that so far have been part of some 4042special "boot loader" code within the Linux kernel. Also, any 4043"initrd" images to be used are no longer part of one big Linux image; 4044instead, kernel and "initrd" are separate images. This implementation 4045serves several purposes: 4046 4047- the same features can be used for other OS or standalone 4048 applications (for instance: using compressed images to reduce the 4049 Flash memory footprint) 4050 4051- it becomes much easier to port new Linux kernel versions because 4052 lots of low-level, hardware dependent stuff are done by U-Boot 4053 4054- the same Linux kernel image can now be used with different "initrd" 4055 images; of course this also means that different kernel images can 4056 be run with the same "initrd". This makes testing easier (you don't 4057 have to build a new "zImage.initrd" Linux image when you just 4058 change a file in your "initrd"). Also, a field-upgrade of the 4059 software is easier now. 4060 4061 4062Linux HOWTO: 4063============ 4064 4065Porting Linux to U-Boot based systems: 4066--------------------------------------- 4067 4068U-Boot cannot save you from doing all the necessary modifications to 4069configure the Linux device drivers for use with your target hardware 4070(no, we don't intend to provide a full virtual machine interface to 4071Linux :-). 4072 4073But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 4074 4075Just make sure your machine specific header file (for instance 4076include/asm-ppc/tqm8xx.h) includes the same definition of the Board 4077Information structure as we define in include/asm-<arch>/u-boot.h, 4078and make sure that your definition of IMAP_ADDR uses the same value 4079as your U-Boot configuration in CONFIG_SYS_IMMR. 4080 4081Note that U-Boot now has a driver model, a unified model for drivers. 4082If you are adding a new driver, plumb it into driver model. If there 4083is no uclass available, you are encouraged to create one. See 4084doc/driver-model. 4085 4086 4087Configuring the Linux kernel: 4088----------------------------- 4089 4090No specific requirements for U-Boot. Make sure you have some root 4091device (initial ramdisk, NFS) for your target system. 4092 4093 4094Building a Linux Image: 4095----------------------- 4096 4097With U-Boot, "normal" build targets like "zImage" or "bzImage" are 4098not used. If you use recent kernel source, a new build target 4099"uImage" will exist which automatically builds an image usable by 4100U-Boot. Most older kernels also have support for a "pImage" target, 4101which was introduced for our predecessor project PPCBoot and uses a 4102100% compatible format. 4103 4104Example: 4105 4106 make TQM850L_defconfig 4107 make oldconfig 4108 make dep 4109 make uImage 4110 4111The "uImage" build target uses a special tool (in 'tools/mkimage') to 4112encapsulate a compressed Linux kernel image with header information, 4113CRC32 checksum etc. for use with U-Boot. This is what we are doing: 4114 4115* build a standard "vmlinux" kernel image (in ELF binary format): 4116 4117* convert the kernel into a raw binary image: 4118 4119 ${CROSS_COMPILE}-objcopy -O binary \ 4120 -R .note -R .comment \ 4121 -S vmlinux linux.bin 4122 4123* compress the binary image: 4124 4125 gzip -9 linux.bin 4126 4127* package compressed binary image for U-Boot: 4128 4129 mkimage -A ppc -O linux -T kernel -C gzip \ 4130 -a 0 -e 0 -n "Linux Kernel Image" \ 4131 -d linux.bin.gz uImage 4132 4133 4134The "mkimage" tool can also be used to create ramdisk images for use 4135with U-Boot, either separated from the Linux kernel image, or 4136combined into one file. "mkimage" encapsulates the images with a 64 4137byte header containing information about target architecture, 4138operating system, image type, compression method, entry points, time 4139stamp, CRC32 checksums, etc. 4140 4141"mkimage" can be called in two ways: to verify existing images and 4142print the header information, or to build new images. 4143 4144In the first form (with "-l" option) mkimage lists the information 4145contained in the header of an existing U-Boot image; this includes 4146checksum verification: 4147 4148 tools/mkimage -l image 4149 -l ==> list image header information 4150 4151The second form (with "-d" option) is used to build a U-Boot image 4152from a "data file" which is used as image payload: 4153 4154 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 4155 -n name -d data_file image 4156 -A ==> set architecture to 'arch' 4157 -O ==> set operating system to 'os' 4158 -T ==> set image type to 'type' 4159 -C ==> set compression type 'comp' 4160 -a ==> set load address to 'addr' (hex) 4161 -e ==> set entry point to 'ep' (hex) 4162 -n ==> set image name to 'name' 4163 -d ==> use image data from 'datafile' 4164 4165Right now, all Linux kernels for PowerPC systems use the same load 4166address (0x00000000), but the entry point address depends on the 4167kernel version: 4168 4169- 2.2.x kernels have the entry point at 0x0000000C, 4170- 2.3.x and later kernels have the entry point at 0x00000000. 4171 4172So a typical call to build a U-Boot image would read: 4173 4174 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4175 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 4176 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 4177 > examples/uImage.TQM850L 4178 Image Name: 2.4.4 kernel for TQM850L 4179 Created: Wed Jul 19 02:34:59 2000 4180 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4181 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4182 Load Address: 0x00000000 4183 Entry Point: 0x00000000 4184 4185To verify the contents of the image (or check for corruption): 4186 4187 -> tools/mkimage -l examples/uImage.TQM850L 4188 Image Name: 2.4.4 kernel for TQM850L 4189 Created: Wed Jul 19 02:34:59 2000 4190 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4191 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 4192 Load Address: 0x00000000 4193 Entry Point: 0x00000000 4194 4195NOTE: for embedded systems where boot time is critical you can trade 4196speed for memory and install an UNCOMPRESSED image instead: this 4197needs more space in Flash, but boots much faster since it does not 4198need to be uncompressed: 4199 4200 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 4201 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 4202 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 4203 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 4204 > examples/uImage.TQM850L-uncompressed 4205 Image Name: 2.4.4 kernel for TQM850L 4206 Created: Wed Jul 19 02:34:59 2000 4207 Image Type: PowerPC Linux Kernel Image (uncompressed) 4208 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 4209 Load Address: 0x00000000 4210 Entry Point: 0x00000000 4211 4212 4213Similar you can build U-Boot images from a 'ramdisk.image.gz' file 4214when your kernel is intended to use an initial ramdisk: 4215 4216 -> tools/mkimage -n 'Simple Ramdisk Image' \ 4217 > -A ppc -O linux -T ramdisk -C gzip \ 4218 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 4219 Image Name: Simple Ramdisk Image 4220 Created: Wed Jan 12 14:01:50 2000 4221 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4222 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 4223 Load Address: 0x00000000 4224 Entry Point: 0x00000000 4225 4226The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i" 4227option performs the converse operation of the mkimage's second form (the "-d" 4228option). Given an image built by mkimage, the dumpimage extracts a "data file" 4229from the image: 4230 4231 tools/dumpimage -i image -T type -p position data_file 4232 -i ==> extract from the 'image' a specific 'data_file' 4233 -T ==> set image type to 'type' 4234 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image' 4235 4236 4237Installing a Linux Image: 4238------------------------- 4239 4240To downloading a U-Boot image over the serial (console) interface, 4241you must convert the image to S-Record format: 4242 4243 objcopy -I binary -O srec examples/image examples/image.srec 4244 4245The 'objcopy' does not understand the information in the U-Boot 4246image header, so the resulting S-Record file will be relative to 4247address 0x00000000. To load it to a given address, you need to 4248specify the target address as 'offset' parameter with the 'loads' 4249command. 4250 4251Example: install the image to address 0x40100000 (which on the 4252TQM8xxL is in the first Flash bank): 4253 4254 => erase 40100000 401FFFFF 4255 4256 .......... done 4257 Erased 8 sectors 4258 4259 => loads 40100000 4260 ## Ready for S-Record download ... 4261 ~>examples/image.srec 4262 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 4263 ... 4264 15989 15990 15991 15992 4265 [file transfer complete] 4266 [connected] 4267 ## Start Addr = 0x00000000 4268 4269 4270You can check the success of the download using the 'iminfo' command; 4271this includes a checksum verification so you can be sure no data 4272corruption happened: 4273 4274 => imi 40100000 4275 4276 ## Checking Image at 40100000 ... 4277 Image Name: 2.2.13 for initrd on TQM850L 4278 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4279 Data Size: 335725 Bytes = 327 kB = 0 MB 4280 Load Address: 00000000 4281 Entry Point: 0000000c 4282 Verifying Checksum ... OK 4283 4284 4285Boot Linux: 4286----------- 4287 4288The "bootm" command is used to boot an application that is stored in 4289memory (RAM or Flash). In case of a Linux kernel image, the contents 4290of the "bootargs" environment variable is passed to the kernel as 4291parameters. You can check and modify this variable using the 4292"printenv" and "setenv" commands: 4293 4294 4295 => printenv bootargs 4296 bootargs=root=/dev/ram 4297 4298 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4299 4300 => printenv bootargs 4301 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4302 4303 => bootm 40020000 4304 ## Booting Linux kernel at 40020000 ... 4305 Image Name: 2.2.13 for NFS on TQM850L 4306 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4307 Data Size: 381681 Bytes = 372 kB = 0 MB 4308 Load Address: 00000000 4309 Entry Point: 0000000c 4310 Verifying Checksum ... OK 4311 Uncompressing Kernel Image ... OK 4312 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 4313 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 4314 time_init: decrementer frequency = 187500000/60 4315 Calibrating delay loop... 49.77 BogoMIPS 4316 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 4317 ... 4318 4319If you want to boot a Linux kernel with initial RAM disk, you pass 4320the memory addresses of both the kernel and the initrd image (PPBCOOT 4321format!) to the "bootm" command: 4322 4323 => imi 40100000 40200000 4324 4325 ## Checking Image at 40100000 ... 4326 Image Name: 2.2.13 for initrd on TQM850L 4327 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4328 Data Size: 335725 Bytes = 327 kB = 0 MB 4329 Load Address: 00000000 4330 Entry Point: 0000000c 4331 Verifying Checksum ... OK 4332 4333 ## Checking Image at 40200000 ... 4334 Image Name: Simple Ramdisk Image 4335 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4336 Data Size: 566530 Bytes = 553 kB = 0 MB 4337 Load Address: 00000000 4338 Entry Point: 00000000 4339 Verifying Checksum ... OK 4340 4341 => bootm 40100000 40200000 4342 ## Booting Linux kernel at 40100000 ... 4343 Image Name: 2.2.13 for initrd on TQM850L 4344 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4345 Data Size: 335725 Bytes = 327 kB = 0 MB 4346 Load Address: 00000000 4347 Entry Point: 0000000c 4348 Verifying Checksum ... OK 4349 Uncompressing Kernel Image ... OK 4350 ## Loading RAMDisk Image at 40200000 ... 4351 Image Name: Simple Ramdisk Image 4352 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 4353 Data Size: 566530 Bytes = 553 kB = 0 MB 4354 Load Address: 00000000 4355 Entry Point: 00000000 4356 Verifying Checksum ... OK 4357 Loading Ramdisk ... OK 4358 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 4359 Boot arguments: root=/dev/ram 4360 time_init: decrementer frequency = 187500000/60 4361 Calibrating delay loop... 49.77 BogoMIPS 4362 ... 4363 RAMDISK: Compressed image found at block 0 4364 VFS: Mounted root (ext2 filesystem). 4365 4366 bash# 4367 4368Boot Linux and pass a flat device tree: 4369----------- 4370 4371First, U-Boot must be compiled with the appropriate defines. See the section 4372titled "Linux Kernel Interface" above for a more in depth explanation. The 4373following is an example of how to start a kernel and pass an updated 4374flat device tree: 4375 4376=> print oftaddr 4377oftaddr=0x300000 4378=> print oft 4379oft=oftrees/mpc8540ads.dtb 4380=> tftp $oftaddr $oft 4381Speed: 1000, full duplex 4382Using TSEC0 device 4383TFTP from server 192.168.1.1; our IP address is 192.168.1.101 4384Filename 'oftrees/mpc8540ads.dtb'. 4385Load address: 0x300000 4386Loading: # 4387done 4388Bytes transferred = 4106 (100a hex) 4389=> tftp $loadaddr $bootfile 4390Speed: 1000, full duplex 4391Using TSEC0 device 4392TFTP from server 192.168.1.1; our IP address is 192.168.1.2 4393Filename 'uImage'. 4394Load address: 0x200000 4395Loading:############ 4396done 4397Bytes transferred = 1029407 (fb51f hex) 4398=> print loadaddr 4399loadaddr=200000 4400=> print oftaddr 4401oftaddr=0x300000 4402=> bootm $loadaddr - $oftaddr 4403## Booting image at 00200000 ... 4404 Image Name: Linux-2.6.17-dirty 4405 Image Type: PowerPC Linux Kernel Image (gzip compressed) 4406 Data Size: 1029343 Bytes = 1005.2 kB 4407 Load Address: 00000000 4408 Entry Point: 00000000 4409 Verifying Checksum ... OK 4410 Uncompressing Kernel Image ... OK 4411Booting using flat device tree at 0x300000 4412Using MPC85xx ADS machine description 4413Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 4414[snip] 4415 4416 4417More About U-Boot Image Types: 4418------------------------------ 4419 4420U-Boot supports the following image types: 4421 4422 "Standalone Programs" are directly runnable in the environment 4423 provided by U-Boot; it is expected that (if they behave 4424 well) you can continue to work in U-Boot after return from 4425 the Standalone Program. 4426 "OS Kernel Images" are usually images of some Embedded OS which 4427 will take over control completely. Usually these programs 4428 will install their own set of exception handlers, device 4429 drivers, set up the MMU, etc. - this means, that you cannot 4430 expect to re-enter U-Boot except by resetting the CPU. 4431 "RAMDisk Images" are more or less just data blocks, and their 4432 parameters (address, size) are passed to an OS kernel that is 4433 being started. 4434 "Multi-File Images" contain several images, typically an OS 4435 (Linux) kernel image and one or more data images like 4436 RAMDisks. This construct is useful for instance when you want 4437 to boot over the network using BOOTP etc., where the boot 4438 server provides just a single image file, but you want to get 4439 for instance an OS kernel and a RAMDisk image. 4440 4441 "Multi-File Images" start with a list of image sizes, each 4442 image size (in bytes) specified by an "uint32_t" in network 4443 byte order. This list is terminated by an "(uint32_t)0". 4444 Immediately after the terminating 0 follow the images, one by 4445 one, all aligned on "uint32_t" boundaries (size rounded up to 4446 a multiple of 4 bytes). 4447 4448 "Firmware Images" are binary images containing firmware (like 4449 U-Boot or FPGA images) which usually will be programmed to 4450 flash memory. 4451 4452 "Script files" are command sequences that will be executed by 4453 U-Boot's command interpreter; this feature is especially 4454 useful when you configure U-Boot to use a real shell (hush) 4455 as command interpreter. 4456 4457Booting the Linux zImage: 4458------------------------- 4459 4460On some platforms, it's possible to boot Linux zImage. This is done 4461using the "bootz" command. The syntax of "bootz" command is the same 4462as the syntax of "bootm" command. 4463 4464Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4465kernel with raw initrd images. The syntax is slightly different, the 4466address of the initrd must be augmented by it's size, in the following 4467format: "<initrd addres>:<initrd size>". 4468 4469 4470Standalone HOWTO: 4471================= 4472 4473One of the features of U-Boot is that you can dynamically load and 4474run "standalone" applications, which can use some resources of 4475U-Boot like console I/O functions or interrupt services. 4476 4477Two simple examples are included with the sources: 4478 4479"Hello World" Demo: 4480------------------- 4481 4482'examples/hello_world.c' contains a small "Hello World" Demo 4483application; it is automatically compiled when you build U-Boot. 4484It's configured to run at address 0x00040004, so you can play with it 4485like that: 4486 4487 => loads 4488 ## Ready for S-Record download ... 4489 ~>examples/hello_world.srec 4490 1 2 3 4 5 6 7 8 9 10 11 ... 4491 [file transfer complete] 4492 [connected] 4493 ## Start Addr = 0x00040004 4494 4495 => go 40004 Hello World! This is a test. 4496 ## Starting application at 0x00040004 ... 4497 Hello World 4498 argc = 7 4499 argv[0] = "40004" 4500 argv[1] = "Hello" 4501 argv[2] = "World!" 4502 argv[3] = "This" 4503 argv[4] = "is" 4504 argv[5] = "a" 4505 argv[6] = "test." 4506 argv[7] = "<NULL>" 4507 Hit any key to exit ... 4508 4509 ## Application terminated, rc = 0x0 4510 4511Another example, which demonstrates how to register a CPM interrupt 4512handler with the U-Boot code, can be found in 'examples/timer.c'. 4513Here, a CPM timer is set up to generate an interrupt every second. 4514The interrupt service routine is trivial, just printing a '.' 4515character, but this is just a demo program. The application can be 4516controlled by the following keys: 4517 4518 ? - print current values og the CPM Timer registers 4519 b - enable interrupts and start timer 4520 e - stop timer and disable interrupts 4521 q - quit application 4522 4523 => loads 4524 ## Ready for S-Record download ... 4525 ~>examples/timer.srec 4526 1 2 3 4 5 6 7 8 9 10 11 ... 4527 [file transfer complete] 4528 [connected] 4529 ## Start Addr = 0x00040004 4530 4531 => go 40004 4532 ## Starting application at 0x00040004 ... 4533 TIMERS=0xfff00980 4534 Using timer 1 4535 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4536 4537Hit 'b': 4538 [q, b, e, ?] Set interval 1000000 us 4539 Enabling timer 4540Hit '?': 4541 [q, b, e, ?] ........ 4542 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4543Hit '?': 4544 [q, b, e, ?] . 4545 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4546Hit '?': 4547 [q, b, e, ?] . 4548 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4549Hit '?': 4550 [q, b, e, ?] . 4551 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4552Hit 'e': 4553 [q, b, e, ?] ...Stopping timer 4554Hit 'q': 4555 [q, b, e, ?] ## Application terminated, rc = 0x0 4556 4557 4558Minicom warning: 4559================ 4560 4561Over time, many people have reported problems when trying to use the 4562"minicom" terminal emulation program for serial download. I (wd) 4563consider minicom to be broken, and recommend not to use it. Under 4564Unix, I recommend to use C-Kermit for general purpose use (and 4565especially for kermit binary protocol download ("loadb" command), and 4566use "cu" for S-Record download ("loads" command). See 4567http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4568for help with kermit. 4569 4570 4571Nevertheless, if you absolutely want to use it try adding this 4572configuration to your "File transfer protocols" section: 4573 4574 Name Program Name U/D FullScr IO-Red. Multi 4575 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4576 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4577 4578 4579NetBSD Notes: 4580============= 4581 4582Starting at version 0.9.2, U-Boot supports NetBSD both as host 4583(build U-Boot) and target system (boots NetBSD/mpc8xx). 4584 4585Building requires a cross environment; it is known to work on 4586NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4587need gmake since the Makefiles are not compatible with BSD make). 4588Note that the cross-powerpc package does not install include files; 4589attempting to build U-Boot will fail because <machine/ansi.h> is 4590missing. This file has to be installed and patched manually: 4591 4592 # cd /usr/pkg/cross/powerpc-netbsd/include 4593 # mkdir powerpc 4594 # ln -s powerpc machine 4595 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4596 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4597 4598Native builds *don't* work due to incompatibilities between native 4599and U-Boot include files. 4600 4601Booting assumes that (the first part of) the image booted is a 4602stage-2 loader which in turn loads and then invokes the kernel 4603proper. Loader sources will eventually appear in the NetBSD source 4604tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4605meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4606 4607 4608Implementation Internals: 4609========================= 4610 4611The following is not intended to be a complete description of every 4612implementation detail. However, it should help to understand the 4613inner workings of U-Boot and make it easier to port it to custom 4614hardware. 4615 4616 4617Initial Stack, Global Data: 4618--------------------------- 4619 4620The implementation of U-Boot is complicated by the fact that U-Boot 4621starts running out of ROM (flash memory), usually without access to 4622system RAM (because the memory controller is not initialized yet). 4623This means that we don't have writable Data or BSS segments, and BSS 4624is not initialized as zero. To be able to get a C environment working 4625at all, we have to allocate at least a minimal stack. Implementation 4626options for this are defined and restricted by the CPU used: Some CPU 4627models provide on-chip memory (like the IMMR area on MPC8xx and 4628MPC826x processors), on others (parts of) the data cache can be 4629locked as (mis-) used as memory, etc. 4630 4631 Chris Hallinan posted a good summary of these issues to the 4632 U-Boot mailing list: 4633 4634 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4635 From: "Chris Hallinan" <clh@net1plus.com> 4636 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4637 ... 4638 4639 Correct me if I'm wrong, folks, but the way I understand it 4640 is this: Using DCACHE as initial RAM for Stack, etc, does not 4641 require any physical RAM backing up the cache. The cleverness 4642 is that the cache is being used as a temporary supply of 4643 necessary storage before the SDRAM controller is setup. It's 4644 beyond the scope of this list to explain the details, but you 4645 can see how this works by studying the cache architecture and 4646 operation in the architecture and processor-specific manuals. 4647 4648 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4649 is another option for the system designer to use as an 4650 initial stack/RAM area prior to SDRAM being available. Either 4651 option should work for you. Using CS 4 should be fine if your 4652 board designers haven't used it for something that would 4653 cause you grief during the initial boot! It is frequently not 4654 used. 4655 4656 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4657 with your processor/board/system design. The default value 4658 you will find in any recent u-boot distribution in 4659 walnut.h should work for you. I'd set it to a value larger 4660 than your SDRAM module. If you have a 64MB SDRAM module, set 4661 it above 400_0000. Just make sure your board has no resources 4662 that are supposed to respond to that address! That code in 4663 start.S has been around a while and should work as is when 4664 you get the config right. 4665 4666 -Chris Hallinan 4667 DS4.COM, Inc. 4668 4669It is essential to remember this, since it has some impact on the C 4670code for the initialization procedures: 4671 4672* Initialized global data (data segment) is read-only. Do not attempt 4673 to write it. 4674 4675* Do not use any uninitialized global data (or implicitly initialized 4676 as zero data - BSS segment) at all - this is undefined, initiali- 4677 zation is performed later (when relocating to RAM). 4678 4679* Stack space is very limited. Avoid big data buffers or things like 4680 that. 4681 4682Having only the stack as writable memory limits means we cannot use 4683normal global data to share information between the code. But it 4684turned out that the implementation of U-Boot can be greatly 4685simplified by making a global data structure (gd_t) available to all 4686functions. We could pass a pointer to this data as argument to _all_ 4687functions, but this would bloat the code. Instead we use a feature of 4688the GCC compiler (Global Register Variables) to share the data: we 4689place a pointer (gd) to the global data into a register which we 4690reserve for this purpose. 4691 4692When choosing a register for such a purpose we are restricted by the 4693relevant (E)ABI specifications for the current architecture, and by 4694GCC's implementation. 4695 4696For PowerPC, the following registers have specific use: 4697 R1: stack pointer 4698 R2: reserved for system use 4699 R3-R4: parameter passing and return values 4700 R5-R10: parameter passing 4701 R13: small data area pointer 4702 R30: GOT pointer 4703 R31: frame pointer 4704 4705 (U-Boot also uses R12 as internal GOT pointer. r12 4706 is a volatile register so r12 needs to be reset when 4707 going back and forth between asm and C) 4708 4709 ==> U-Boot will use R2 to hold a pointer to the global data 4710 4711 Note: on PPC, we could use a static initializer (since the 4712 address of the global data structure is known at compile time), 4713 but it turned out that reserving a register results in somewhat 4714 smaller code - although the code savings are not that big (on 4715 average for all boards 752 bytes for the whole U-Boot image, 4716 624 text + 127 data). 4717 4718On ARM, the following registers are used: 4719 4720 R0: function argument word/integer result 4721 R1-R3: function argument word 4722 R9: platform specific 4723 R10: stack limit (used only if stack checking is enabled) 4724 R11: argument (frame) pointer 4725 R12: temporary workspace 4726 R13: stack pointer 4727 R14: link register 4728 R15: program counter 4729 4730 ==> U-Boot will use R9 to hold a pointer to the global data 4731 4732 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4733 4734On Nios II, the ABI is documented here: 4735 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4736 4737 ==> U-Boot will use gp to hold a pointer to the global data 4738 4739 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4740 to access small data sections, so gp is free. 4741 4742On NDS32, the following registers are used: 4743 4744 R0-R1: argument/return 4745 R2-R5: argument 4746 R15: temporary register for assembler 4747 R16: trampoline register 4748 R28: frame pointer (FP) 4749 R29: global pointer (GP) 4750 R30: link register (LP) 4751 R31: stack pointer (SP) 4752 PC: program counter (PC) 4753 4754 ==> U-Boot will use R10 to hold a pointer to the global data 4755 4756NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4757or current versions of GCC may "optimize" the code too much. 4758 4759On RISC-V, the following registers are used: 4760 4761 x0: hard-wired zero (zero) 4762 x1: return address (ra) 4763 x2: stack pointer (sp) 4764 x3: global pointer (gp) 4765 x4: thread pointer (tp) 4766 x5: link register (t0) 4767 x8: frame pointer (fp) 4768 x10-x11: arguments/return values (a0-1) 4769 x12-x17: arguments (a2-7) 4770 x28-31: temporaries (t3-6) 4771 pc: program counter (pc) 4772 4773 ==> U-Boot will use gp to hold a pointer to the global data 4774 4775Memory Management: 4776------------------ 4777 4778U-Boot runs in system state and uses physical addresses, i.e. the 4779MMU is not used either for address mapping nor for memory protection. 4780 4781The available memory is mapped to fixed addresses using the memory 4782controller. In this process, a contiguous block is formed for each 4783memory type (Flash, SDRAM, SRAM), even when it consists of several 4784physical memory banks. 4785 4786U-Boot is installed in the first 128 kB of the first Flash bank (on 4787TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4788booting and sizing and initializing DRAM, the code relocates itself 4789to the upper end of DRAM. Immediately below the U-Boot code some 4790memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4791configuration setting]. Below that, a structure with global Board 4792Info data is placed, followed by the stack (growing downward). 4793 4794Additionally, some exception handler code is copied to the low 8 kB 4795of DRAM (0x00000000 ... 0x00001FFF). 4796 4797So a typical memory configuration with 16 MB of DRAM could look like 4798this: 4799 4800 0x0000 0000 Exception Vector code 4801 : 4802 0x0000 1FFF 4803 0x0000 2000 Free for Application Use 4804 : 4805 : 4806 4807 : 4808 : 4809 0x00FB FF20 Monitor Stack (Growing downward) 4810 0x00FB FFAC Board Info Data and permanent copy of global data 4811 0x00FC 0000 Malloc Arena 4812 : 4813 0x00FD FFFF 4814 0x00FE 0000 RAM Copy of Monitor Code 4815 ... eventually: LCD or video framebuffer 4816 ... eventually: pRAM (Protected RAM - unchanged by reset) 4817 0x00FF FFFF [End of RAM] 4818 4819 4820System Initialization: 4821---------------------- 4822 4823In the reset configuration, U-Boot starts at the reset entry point 4824(on most PowerPC systems at address 0x00000100). Because of the reset 4825configuration for CS0# this is a mirror of the on board Flash memory. 4826To be able to re-map memory U-Boot then jumps to its link address. 4827To be able to implement the initialization code in C, a (small!) 4828initial stack is set up in the internal Dual Ported RAM (in case CPUs 4829which provide such a feature like), or in a locked part of the data 4830cache. After that, U-Boot initializes the CPU core, the caches and 4831the SIU. 4832 4833Next, all (potentially) available memory banks are mapped using a 4834preliminary mapping. For example, we put them on 512 MB boundaries 4835(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4836on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4837programmed for SDRAM access. Using the temporary configuration, a 4838simple memory test is run that determines the size of the SDRAM 4839banks. 4840 4841When there is more than one SDRAM bank, and the banks are of 4842different size, the largest is mapped first. For equal size, the first 4843bank (CS2#) is mapped first. The first mapping is always for address 48440x00000000, with any additional banks following immediately to create 4845contiguous memory starting from 0. 4846 4847Then, the monitor installs itself at the upper end of the SDRAM area 4848and allocates memory for use by malloc() and for the global Board 4849Info data; also, the exception vector code is copied to the low RAM 4850pages, and the final stack is set up. 4851 4852Only after this relocation will you have a "normal" C environment; 4853until that you are restricted in several ways, mostly because you are 4854running from ROM, and because the code will have to be relocated to a 4855new address in RAM. 4856 4857 4858U-Boot Porting Guide: 4859---------------------- 4860 4861[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4862list, October 2002] 4863 4864 4865int main(int argc, char *argv[]) 4866{ 4867 sighandler_t no_more_time; 4868 4869 signal(SIGALRM, no_more_time); 4870 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4871 4872 if (available_money > available_manpower) { 4873 Pay consultant to port U-Boot; 4874 return 0; 4875 } 4876 4877 Download latest U-Boot source; 4878 4879 Subscribe to u-boot mailing list; 4880 4881 if (clueless) 4882 email("Hi, I am new to U-Boot, how do I get started?"); 4883 4884 while (learning) { 4885 Read the README file in the top level directory; 4886 Read http://www.denx.de/twiki/bin/view/DULG/Manual; 4887 Read applicable doc/*.README; 4888 Read the source, Luke; 4889 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4890 } 4891 4892 if (available_money > toLocalCurrency ($2500)) 4893 Buy a BDI3000; 4894 else 4895 Add a lot of aggravation and time; 4896 4897 if (a similar board exists) { /* hopefully... */ 4898 cp -a board/<similar> board/<myboard> 4899 cp include/configs/<similar>.h include/configs/<myboard>.h 4900 } else { 4901 Create your own board support subdirectory; 4902 Create your own board include/configs/<myboard>.h file; 4903 } 4904 Edit new board/<myboard> files 4905 Edit new include/configs/<myboard>.h 4906 4907 while (!accepted) { 4908 while (!running) { 4909 do { 4910 Add / modify source code; 4911 } until (compiles); 4912 Debug; 4913 if (clueless) 4914 email("Hi, I am having problems..."); 4915 } 4916 Send patch file to the U-Boot email list; 4917 if (reasonable critiques) 4918 Incorporate improvements from email list code review; 4919 else 4920 Defend code as written; 4921 } 4922 4923 return 0; 4924} 4925 4926void no_more_time (int sig) 4927{ 4928 hire_a_guru(); 4929} 4930 4931 4932Coding Standards: 4933----------------- 4934 4935All contributions to U-Boot should conform to the Linux kernel 4936coding style; see the kernel coding style guide at 4937https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4938script "scripts/Lindent" in your Linux kernel source directory. 4939 4940Source files originating from a different project (for example the 4941MTD subsystem) are generally exempt from these guidelines and are not 4942reformatted to ease subsequent migration to newer versions of those 4943sources. 4944 4945Please note that U-Boot is implemented in C (and to some small parts in 4946Assembler); no C++ is used, so please do not use C++ style comments (//) 4947in your code. 4948 4949Please also stick to the following formatting rules: 4950- remove any trailing white space 4951- use TAB characters for indentation and vertical alignment, not spaces 4952- make sure NOT to use DOS '\r\n' line feeds 4953- do not add more than 2 consecutive empty lines to source files 4954- do not add trailing empty lines to source files 4955 4956Submissions which do not conform to the standards may be returned 4957with a request to reformat the changes. 4958 4959 4960Submitting Patches: 4961------------------- 4962 4963Since the number of patches for U-Boot is growing, we need to 4964establish some rules. Submissions which do not conform to these rules 4965may be rejected, even when they contain important and valuable stuff. 4966 4967Please see http://www.denx.de/wiki/U-Boot/Patches for details. 4968 4969Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 4970see https://lists.denx.de/listinfo/u-boot 4971 4972When you send a patch, please include the following information with 4973it: 4974 4975* For bug fixes: a description of the bug and how your patch fixes 4976 this bug. Please try to include a way of demonstrating that the 4977 patch actually fixes something. 4978 4979* For new features: a description of the feature and your 4980 implementation. 4981 4982* A CHANGELOG entry as plaintext (separate from the patch) 4983 4984* For major contributions, add a MAINTAINERS file with your 4985 information and associated file and directory references. 4986 4987* When you add support for a new board, don't forget to add a 4988 maintainer e-mail address to the boards.cfg file, too. 4989 4990* If your patch adds new configuration options, don't forget to 4991 document these in the README file. 4992 4993* The patch itself. If you are using git (which is *strongly* 4994 recommended) you can easily generate the patch using the 4995 "git format-patch". If you then use "git send-email" to send it to 4996 the U-Boot mailing list, you will avoid most of the common problems 4997 with some other mail clients. 4998 4999 If you cannot use git, use "diff -purN OLD NEW". If your version of 5000 diff does not support these options, then get the latest version of 5001 GNU diff. 5002 5003 The current directory when running this command shall be the parent 5004 directory of the U-Boot source tree (i. e. please make sure that 5005 your patch includes sufficient directory information for the 5006 affected files). 5007 5008 We prefer patches as plain text. MIME attachments are discouraged, 5009 and compressed attachments must not be used. 5010 5011* If one logical set of modifications affects or creates several 5012 files, all these changes shall be submitted in a SINGLE patch file. 5013 5014* Changesets that contain different, unrelated modifications shall be 5015 submitted as SEPARATE patches, one patch per changeset. 5016 5017 5018Notes: 5019 5020* Before sending the patch, run the buildman script on your patched 5021 source tree and make sure that no errors or warnings are reported 5022 for any of the boards. 5023 5024* Keep your modifications to the necessary minimum: A patch 5025 containing several unrelated changes or arbitrary reformats will be 5026 returned with a request to re-formatting / split it. 5027 5028* If you modify existing code, make sure that your new code does not 5029 add to the memory footprint of the code ;-) Small is beautiful! 5030 When adding new features, these should compile conditionally only 5031 (using #ifdef), and the resulting code with the new feature 5032 disabled must not need more memory than the old code without your 5033 modification. 5034 5035* Remember that there is a size limit of 100 kB per message on the 5036 u-boot mailing list. Bigger patches will be moderated. If they are 5037 reasonable and not too big, they will be acknowledged. But patches 5038 bigger than the size limit should be avoided. 5039