1# 2# (C) Copyright 2000 - 2002 3# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4# 5# See file CREDITS for list of people who contributed to this 6# project. 7# 8# This program is free software; you can redistribute it and/or 9# modify it under the terms of the GNU General Public License as 10# published by the Free Software Foundation; either version 2 of 11# the License, or (at your option) any later version. 12# 13# This program is distributed in the hope that it will be useful, 14# but WITHOUT ANY WARRANTY; without even the implied warranty of 15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16# GNU General Public License for more details. 17# 18# You should have received a copy of the GNU General Public License 19# along with this program; if not, write to the Free Software 20# Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21# MA 02111-1307 USA 22# 23 24Summary: 25======== 26 27This directory contains the source code for U-Boot, a boot loader for 28Embedded boards based on PowerPC and ARM processors, which can be 29installed in a boot ROM and used to initialize and test the hardware 30or to download and run application code. 31 32The development of U-Boot is closely related to Linux: some parts of 33the source code originate in the Linux source tree, we have some 34header files in common, and special provision has been made to 35support booting of Linux images. 36 37Some attention has been paid to make this software easily 38configurable and extendable. For instance, all monitor commands are 39implemented with the same call interface, so that it's very easy to 40add new commands. Also, instead of permanently adding rarely used 41code (for instance hardware test utilities) to the monitor, you can 42load and run it dynamically. 43 44 45Status: 46======= 47 48In general, all boards for which a configuration option exists in the 49Makefile have been tested to some extent and can be considered 50"working". In fact, many of them are used in production systems. 51 52In case of problems see the CHANGELOG and CREDITS files to find out 53who contributed the specific port. 54 55 56Where to get help: 57================== 58 59In case you have questions about, problems with or contributions for 60U-Boot you should send a message to the U-Boot mailing list at 61<u-boot-users@lists.sourceforge.net>. There is also an archive of 62previous traffic on the mailing list - please search the archive 63before asking FAQ's. Please see 64http://lists.sourceforge.net/lists/listinfo/u-boot-users/ 65 66 67Where we come from: 68=================== 69 70- start from 8xxrom sources 71- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 72- clean up code 73- make it easier to add custom boards 74- make it possible to add other [PowerPC] CPUs 75- extend functions, especially: 76 * Provide extended interface to Linux boot loader 77 * S-Record download 78 * network boot 79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot 80- create ARMBoot project (http://sourceforge.net/projects/armboot) 81- add other CPU families (starting with ARM) 82- create U-Boot project (http://sourceforge.net/projects/u-boot) 83 84 85Names and Spelling: 86=================== 87 88The "official" name of this project is "Das U-Boot". The spelling 89"U-Boot" shall be used in all written text (documentation, comments 90in source files etc.). Example: 91 92 This is the README file for the U-Boot project. 93 94File names etc. shall be based on the string "u-boot". Examples: 95 96 include/asm-ppc/u-boot.h 97 98 #include <asm/u-boot.h> 99 100Variable names, preprocessor constants etc. shall be either based on 101the string "u_boot" or on "U_BOOT". Example: 102 103 U_BOOT_VERSION u_boot_logo 104 IH_OS_U_BOOT u_boot_hush_start 105 106 107Versioning: 108=========== 109 110U-Boot uses a 3 level version number containing a version, a 111sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2", 112sub-version "34", and patchlevel "4". 113 114The patchlevel is used to indicate certain stages of development 115between released versions, i. e. officially released versions of 116U-Boot will always have a patchlevel of "0". 117 118 119Directory Hierarchy: 120==================== 121 122- board Board dependend files 123- common Misc architecture independend functions 124- cpu CPU specific files 125- disk Code for disk drive partition handling 126- doc Documentation (don't expect too much) 127- drivers Common used device drivers 128- dtt Digital Thermometer and Thermostat drivers 129- examples Example code for standalone applications, etc. 130- include Header Files 131- disk Harddisk interface code 132- net Networking code 133- ppc Files generic to PowerPC architecture 134- post Power On Self Test 135- post/arch Symlink to architecture specific Power On Self Test 136- post/arch-ppc PowerPC architecture specific Power On Self Test 137- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test 138- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test 139- rtc Real Time Clock drivers 140- tools Tools to build S-Record or U-Boot images, etc. 141 142- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 143- cpu/mpc5xx Files specific to Motorola MPC5xx CPUs 144- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs 145- cpu/mpc824x Files specific to Motorola MPC824x CPUs 146- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 147- cpu/ppc4xx Files specific to IBM 4xx CPUs 148 149- board/LEOX/ Files specific to boards manufactured by The LEOX team 150- board/LEOX/elpt860 Files specific to ELPT860 boards 151- board/RPXClassic 152 Files specific to RPXClassic boards 153- board/RPXlite Files specific to RPXlite boards 154- board/c2mon Files specific to c2mon boards 155- board/cmi Files specific to cmi boards 156- board/cogent Files specific to Cogent boards 157 (need further configuration) 158 Files specific to CPCIISER4 boards 159- board/cpu86 Files specific to CPU86 boards 160- board/cray/ Files specific to boards manufactured by Cray 161- board/cray/L1 Files specific to L1 boards 162- board/cu824 Files specific to CU824 boards 163- board/ebony Files specific to IBM Ebony board 164- board/eric Files specific to ERIC boards 165- board/esd/ Files specific to boards manufactured by ESD 166- board/esd/adciop Files specific to ADCIOP boards 167- board/esd/ar405 Files specific to AR405 boards 168- board/esd/canbt Files specific to CANBT boards 169- board/esd/cpci405 Files specific to CPCI405 boards 170- board/esd/cpciiser4 Files specific to CPCIISER4 boards 171- board/esd/common Common files for ESD boards 172- board/esd/dasa_sim Files specific to DASA_SIM boards 173- board/esd/du405 Files specific to DU405 boards 174- board/esd/ocrtc Files specific to OCRTC boards 175- board/esd/pci405 Files specific to PCI405 boards 176- board/esteem192e 177 Files specific to ESTEEM192E boards 178- board/etx094 Files specific to ETX_094 boards 179- board/evb64260 180 Files specific to EVB64260 boards 181- board/fads Files specific to FADS boards 182- board/flagadm Files specific to FLAGADM boards 183- board/gen860t Files specific to GEN860T boards 184- board/genietv Files specific to GENIETV boards 185- board/gth Files specific to GTH boards 186- board/hermes Files specific to HERMES boards 187- board/hymod Files specific to HYMOD boards 188- board/icu862 Files specific to ICU862 boards 189- board/ip860 Files specific to IP860 boards 190- board/iphase4539 191 Files specific to Interphase4539 boards 192- board/ivm Files specific to IVMS8/IVML24 boards 193- board/lantec Files specific to LANTEC boards 194- board/lwmon Files specific to LWMON boards 195- board/mbx8xx Files specific to MBX boards 196- board/mpc8260ads 197 Files specific to MMPC8260ADS boards 198- board/mpl/ Files specific to boards manufactured by MPL 199- board/mpl/common Common files for MPL boards 200- board/mpl/pip405 Files specific to PIP405 boards 201- board/mpl/mip405 Files specific to MIP405 boards 202- board/musenki Files specific to MUSEKNI boards 203- board/mvs1 Files specific to MVS1 boards 204- board/nx823 Files specific to NX823 boards 205- board/oxc Files specific to OXC boards 206- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 207- board/pm826 Files specific to PM826 boards 208- board/ppmc8260 209 Files specific to PPMC8260 boards 210- board/rpxsuper 211 Files specific to RPXsuper boards 212- board/rsdproto 213 Files specific to RSDproto boards 214- board/sandpoint 215 Files specific to Sandpoint boards 216- board/sbc8260 Files specific to SBC8260 boards 217- board/sacsng Files specific to SACSng boards 218- board/siemens Files specific to boards manufactured by Siemens AG 219- board/siemens/CCM Files specific to CCM boards 220- board/siemens/IAD210 Files specific to IAD210 boards 221- board/siemens/SCM Files specific to SCM boards 222- board/siemens/pcu_e Files specific to PCU_E boards 223- board/sixnet Files specific to SIXNET boards 224- board/spd8xx Files specific to SPD8xxTS boards 225- board/tqm8260 Files specific to TQM8260 boards 226- board/tqm8xx Files specific to TQM8xxL boards 227- board/w7o Files specific to W7O boards 228- board/walnut405 229 Files specific to Walnut405 boards 230- board/westel/ Files specific to boards manufactured by Westel Wireless 231- board/westel/amx860 Files specific to AMX860 boards 232- board/utx8245 Files specific to UTX8245 boards 233 234Software Configuration: 235======================= 236 237Configuration is usually done using C preprocessor defines; the 238rationale behind that is to avoid dead code whenever possible. 239 240There are two classes of configuration variables: 241 242* Configuration _OPTIONS_: 243 These are selectable by the user and have names beginning with 244 "CONFIG_". 245 246* Configuration _SETTINGS_: 247 These depend on the hardware etc. and should not be meddled with if 248 you don't know what you're doing; they have names beginning with 249 "CFG_". 250 251Later we will add a configuration tool - probably similar to or even 252identical to what's used for the Linux kernel. Right now, we have to 253do the configuration by hand, which means creating some symbolic 254links and editing some configuration files. We use the TQM8xxL boards 255as an example here. 256 257 258Selection of Processor Architecture and Board Type: 259--------------------------------------------------- 260 261For all supported boards there are ready-to-use default 262configurations available; just type "make <board_name>_config". 263 264Example: For a TQM823L module type: 265 266 cd u-boot 267 make TQM823L_config 268 269For the Cogent platform, you need to specify the cpu type as well; 270e.g. "make cogent_mpc8xx_config". And also configure the cogent 271directory according to the instructions in cogent/README. 272 273 274Configuration Options: 275---------------------- 276 277Configuration depends on the combination of board and CPU type; all 278such information is kept in a configuration file 279"include/configs/<board_name>.h". 280 281Example: For a TQM823L module, all configuration settings are in 282"include/configs/TQM823L.h". 283 284 285Many of the options are named exactly as the corresponding Linux 286kernel configuration options. The intention is to make it easier to 287build a config tool - later. 288 289 290The following options need to be configured: 291 292- CPU Type: Define exactly one of 293 294 PowerPC based CPUs: 295 ------------------- 296 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 297 or CONFIG_MPC5xx 298 or CONFIG_MPC824X, CONFIG_MPC8260 299 or CONFIG_IOP480 300 or CONFIG_405GP 301 or CONFIG_440 302 or CONFIG_MPC74xx 303 304 ARM based CPUs: 305 --------------- 306 CONFIG_SA1110 307 CONFIG_ARM7 308 CONFIG_PXA250 309 310 311- Board Type: Define exactly one of 312 313 PowerPC based boards: 314 --------------------- 315 316 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 317 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 318 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 319 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 320 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 321 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 322 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 323 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 324 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 325 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 326 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 327 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 328 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 329 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 330 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 331 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 332 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 333 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 334 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 335 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 336 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 337 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 338 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 339 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 340 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 341 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 342 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 343 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 344 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 345 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L, 346 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI 347 348 ARM based boards: 349 ----------------- 350 351 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 352 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 353 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 354 CONFIG_TRAB 355 356 357- CPU Module Type: (if CONFIG_COGENT is defined) 358 Define exactly one of 359 CONFIG_CMA286_60_OLD 360--- FIXME --- not tested yet: 361 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 362 CONFIG_CMA287_23, CONFIG_CMA287_50 363 364- Motherboard Type: (if CONFIG_COGENT is defined) 365 Define exactly one of 366 CONFIG_CMA101, CONFIG_CMA102 367 368- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 369 Define one or more of 370 CONFIG_CMA302 371 372- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 373 Define one or more of 374 CONFIG_LCD_HEARTBEAT - update a character position on 375 the lcd display every second with 376 a "rotator" |\-/|\-/ 377 378- MPC824X Family Member (if CONFIG_MPC824X is defined) 379 Define exactly one of 380 CONFIG_MPC8240, CONFIG_MPC8245 381 382- 8xx CPU Options: (if using an 8xx cpu) 383 Define one or more of 384 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 385 no 32KHz reference PIT/RTC clock 386 387- Clock Interface: 388 CONFIG_CLOCKS_IN_MHZ 389 390 U-Boot stores all clock information in Hz 391 internally. For binary compatibility with older Linux 392 kernels (which expect the clocks passed in the 393 bd_info data to be in MHz) the environment variable 394 "clocks_in_mhz" can be defined so that U-Boot 395 converts clock data to MHZ before passing it to the 396 Linux kernel. 397 398 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 399 "clocks_in_mhz=1" is automatically included in the 400 default environment. 401 402- Console Interface: 403 Depending on board, define exactly one serial port 404 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 405 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 406 console by defining CONFIG_8xx_CONS_NONE 407 408 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 409 port routines must be defined elsewhere 410 (i.e. serial_init(), serial_getc(), ...) 411 412 CONFIG_CFB_CONSOLE 413 Enables console device for a color framebuffer. Needs following 414 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 415 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 416 (default big endian) 417 VIDEO_HW_RECTFILL graphic chip supports 418 rectangle fill 419 (cf. smiLynxEM) 420 VIDEO_HW_BITBLT graphic chip supports 421 bit-blit (cf. smiLynxEM) 422 VIDEO_VISIBLE_COLS visible pixel columns 423 (cols=pitch) 424 VIDEO_VISIBLE_ROWS visible pixel rows 425 VIDEO_PIXEL_SIZE bytes per pixel 426 VIDEO_DATA_FORMAT graphic data format 427 (0-5, cf. cfb_console.c) 428 VIDEO_FB_ADRS framebuffer address 429 VIDEO_KBD_INIT_FCT keyboard int fct 430 (i.e. i8042_kbd_init()) 431 VIDEO_TSTC_FCT test char fct 432 (i.e. i8042_tstc) 433 VIDEO_GETC_FCT get char fct 434 (i.e. i8042_getc) 435 CONFIG_CONSOLE_CURSOR cursor drawing on/off 436 (requires blink timer 437 cf. i8042.c) 438 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 439 CONFIG_CONSOLE_TIME display time/date info in 440 upper right corner 441 (requires CFG_CMD_DATE) 442 CONFIG_VIDEO_LOGO display Linux logo in 443 upper left corner 444 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 445 linux_logo.h for logo. 446 Requires CONFIG_VIDEO_LOGO 447 CONFIG_CONSOLE_EXTRA_INFO 448 addional board info beside 449 the logo 450 451 When CONFIG_CFB_CONSOLE is defined, video console is 452 default i/o. Serial console can be forced with 453 environment 'console=serial'. 454 455- Console Baudrate: 456 CONFIG_BAUDRATE - in bps 457 Select one of the baudrates listed in 458 CFG_BAUDRATE_TABLE, see below. 459 460- Interrupt driven serial port input: 461 CONFIG_SERIAL_SOFTWARE_FIFO 462 463 PPC405GP only. 464 Use an interrupt handler for receiving data on the 465 serial port. It also enables using hardware handshake 466 (RTS/CTS) and UART's built-in FIFO. Set the number of 467 bytes the interrupt driven input buffer should have. 468 469 Set to 0 to disable this feature (this is the default). 470 This will also disable hardware handshake. 471 472- Boot Delay: CONFIG_BOOTDELAY - in seconds 473 Delay before automatically booting the default image; 474 set to -1 to disable autoboot. 475 476 See doc/README.autoboot for these options that 477 work with CONFIG_BOOTDELAY. None are required. 478 CONFIG_BOOT_RETRY_TIME 479 CONFIG_BOOT_RETRY_MIN 480 CONFIG_AUTOBOOT_KEYED 481 CONFIG_AUTOBOOT_PROMPT 482 CONFIG_AUTOBOOT_DELAY_STR 483 CONFIG_AUTOBOOT_STOP_STR 484 CONFIG_AUTOBOOT_DELAY_STR2 485 CONFIG_AUTOBOOT_STOP_STR2 486 CONFIG_ZERO_BOOTDELAY_CHECK 487 CONFIG_RESET_TO_RETRY 488 489- Autoboot Command: 490 CONFIG_BOOTCOMMAND 491 Only needed when CONFIG_BOOTDELAY is enabled; 492 define a command string that is automatically executed 493 when no character is read on the console interface 494 within "Boot Delay" after reset. 495 496 CONFIG_BOOTARGS 497 This can be used to pass arguments to the bootm 498 command. The value of CONFIG_BOOTARGS goes into the 499 environment value "bootargs". 500 501 CONFIG_RAMBOOT and CONFIG_NFSBOOT 502 The value of these goes into the environment as 503 "ramboot" and "nfsboot" respectively, and can be used 504 as a convenience, when switching between booting from 505 ram and nfs. 506 507- Pre-Boot Commands: 508 CONFIG_PREBOOT 509 510 When this option is #defined, the existence of the 511 environment variable "preboot" will be checked 512 immediately before starting the CONFIG_BOOTDELAY 513 countdown and/or running the auto-boot command resp. 514 entering interactive mode. 515 516 This feature is especially useful when "preboot" is 517 automatically generated or modified. For an example 518 see the LWMON board specific code: here "preboot" is 519 modified when the user holds down a certain 520 combination of keys on the (special) keyboard when 521 booting the systems 522 523- Serial Download Echo Mode: 524 CONFIG_LOADS_ECHO 525 If defined to 1, all characters received during a 526 serial download (using the "loads" command) are 527 echoed back. This might be needed by some terminal 528 emulations (like "cu"), but may as well just take 529 time on others. This setting #define's the initial 530 value of the "loads_echo" environment variable. 531 532- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 533 CONFIG_KGDB_BAUDRATE 534 Select one of the baudrates listed in 535 CFG_BAUDRATE_TABLE, see below. 536 537- Monitor Functions: 538 CONFIG_COMMANDS 539 Most monitor functions can be selected (or 540 de-selected) by adjusting the definition of 541 CONFIG_COMMANDS; to select individual functions, 542 #define CONFIG_COMMANDS by "OR"ing any of the 543 following values: 544 545 #define enables commands: 546 ------------------------- 547 CFG_CMD_ASKENV * ask for env variable 548 CFG_CMD_BDI bdinfo 549 CFG_CMD_BEDBUG Include BedBug Debugger 550 CFG_CMD_BOOTD bootd 551 CFG_CMD_CACHE icache, dcache 552 CFG_CMD_CONSOLE coninfo 553 CFG_CMD_DATE * support for RTC, date/time... 554 CFG_CMD_DHCP DHCP support 555 CFG_CMD_ECHO * echo arguments 556 CFG_CMD_EEPROM * EEPROM read/write support 557 CFG_CMD_ELF bootelf, bootvx 558 CFG_CMD_ENV saveenv 559 CFG_CMD_FDC * Floppy Disk Support 560 CFG_CMD_FDOS * Dos diskette Support 561 CFG_CMD_FLASH flinfo, erase, protect 562 CFG_CMD_FPGA FPGA device initialization support 563 CFG_CMD_I2C * I2C serial bus support 564 CFG_CMD_IDE * IDE harddisk support 565 CFG_CMD_IMI iminfo 566 CFG_CMD_IMMAP * IMMR dump support 567 CFG_CMD_IRQ * irqinfo 568 CFG_CMD_KGDB * kgdb 569 CFG_CMD_LOADB loadb 570 CFG_CMD_LOADS loads 571 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 572 loop, mtest 573 CFG_CMD_MII MII utility commands 574 CFG_CMD_NET bootp, tftpboot, rarpboot 575 CFG_CMD_PCI * pciinfo 576 CFG_CMD_PCMCIA * PCMCIA support 577 CFG_CMD_REGINFO * Register dump 578 CFG_CMD_RUN run command in env variable 579 CFG_CMD_SCSI * SCSI Support 580 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 581 CFG_CMD_SPI * SPI serial bus support 582 CFG_CMD_USB * USB support 583 CFG_CMD_BSP * Board SPecific functions 584 ----------------------------------------------- 585 CFG_CMD_ALL all 586 587 CFG_CMD_DFL Default configuration; at the moment 588 this is includes all commands, except 589 the ones marked with "*" in the list 590 above. 591 592 If you don't define CONFIG_COMMANDS it defaults to 593 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 594 override the default settings in the respective 595 include file. 596 597 EXAMPLE: If you want all functions except of network 598 support you can write: 599 600 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 601 602 603 Note: Don't enable the "icache" and "dcache" commands 604 (configuration option CFG_CMD_CACHE) unless you know 605 what you (and your U-Boot users) are doing. Data 606 cache cannot be enabled on systems like the 8xx or 607 8260 (where accesses to the IMMR region must be 608 uncached), and it cannot be disabled on all other 609 systems where we (mis-) use the data cache to hold an 610 initial stack and some data. 611 612 613 XXX - this list needs to get updated! 614 615- Watchdog: 616 CONFIG_WATCHDOG 617 If this variable is defined, it enables watchdog 618 support. There must support in the platform specific 619 code for a watchdog. For the 8xx and 8260 CPUs, the 620 SIU Watchdog feature is enabled in the SYPCR 621 register. 622 623- Real-Time Clock: 624 625 When CFG_CMD_DATE is selected, the type of the RTC 626 has to be selected, too. Define exactly one of the 627 following options: 628 629 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 630 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 631 CONFIG_RTC_MC146818 - use MC146818 RTC 632 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 633 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 634 CONFIG_RTC_DS164x - use Dallas DS164x RTC 635 636- Timestamp Support: 637 638 When CONFIG_TIMESTAMP is selected, the timestamp 639 (date and time) of an image is printed by image 640 commands like bootm or iminfo. This option is 641 automatically enabled when you select CFG_CMD_DATE . 642 643- Partition Support: 644 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 645 and/or CONFIG_ISO_PARTITION 646 647 If IDE or SCSI support is enabled (CFG_CMD_IDE or 648 CFG_CMD_SCSI) you must configure support for at least 649 one partition type as well. 650 651- IDE Reset method: 652 CONFIG_IDE_RESET_ROUTINE 653 654 Set this to define that instead of a reset Pin, the 655 routine ide_set_reset(int idereset) will be used. 656 657- ATAPI Support: 658 CONFIG_ATAPI 659 660 Set this to enable ATAPI support. 661 662- SCSI Support: 663 At the moment only there is only support for the 664 SYM53C8XX SCSI controller; define 665 CONFIG_SCSI_SYM53C8XX to enable it. 666 667 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 668 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 669 CFG_SCSI_MAX_LUN] can be adjusted to define the 670 maximum numbers of LUNs, SCSI ID's and target 671 devices. 672 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 673 674- NETWORK Support (PCI): 675 CONFIG_EEPRO100 676 Support for Intel 82557/82559/82559ER chips. 677 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 678 write routine for first time initialisation. 679 680 CONFIG_TULIP 681 Support for Digital 2114x chips. 682 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 683 modem chip initialisation (KS8761/QS6611). 684 685 CONFIG_NATSEMI 686 Support for National dp83815 chips. 687 688 CONFIG_NS8382X 689 Support for National dp8382[01] gigabit chips. 690 691- USB Support: 692 At the moment only the UHCI host controller is 693 supported (PIP405, MIP405); define 694 CONFIG_USB_UHCI to enable it. 695 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 696 end define CONFIG_USB_STORAGE to enable the USB 697 storage devices. 698 Note: 699 Supported are USB Keyboards and USB Floppy drives 700 (TEAC FD-05PUB). 701 702- Keyboard Support: 703 CONFIG_ISA_KEYBOARD 704 705 Define this to enable standard (PC-Style) keyboard 706 support 707 708 CONFIG_I8042_KBD 709 Standard PC keyboard driver with US (is default) and 710 GERMAN key layout (switch via environment 'keymap=de') support. 711 Export function i8042_kbd_init, i8042_tstc and i8042_getc 712 for cfb_console. Supports cursor blinking. 713 714- Video support: 715 CONFIG_VIDEO 716 717 Define this to enable video support (for output to 718 video). 719 720 CONFIG_VIDEO_CT69000 721 722 Enable Chips & Technologies 69000 Video chip 723 724 CONFIG_VIDEO_SMI_LYNXEM 725 Enable Silicon Motion SMI 712/710/810 Video chip 726 Videomode are selected via environment 'videomode' with 727 standard LiLo mode numbers. 728 Following modes are supported (* is default): 729 730 800x600 1024x768 1280x1024 731 256 (8bit) 303* 305 307 732 65536 (16bit) 314 317 31a 733 16,7 Mill (24bit) 315 318 31b 734 (i.e. setenv videomode 317; saveenv; reset;) 735 736 CONFIG_VIDEO_SED13806 737 Enable Epson SED13806 driver. This driver supports 8bpp 738 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 739 or CONFIG_VIDEO_SED13806_16BPP 740 741 742- LCD Support: CONFIG_LCD 743 744 Define this to enable LCD support (for output to LCD 745 display); also select one of the supported displays 746 by defining one of these: 747 748 CONFIG_NEC_NL6648AC33: 749 750 NEC NL6648AC33-18. Active, color, single scan. 751 752 CONFIG_NEC_NL6648BC20 753 754 NEC NL6648BC20-08. 6.5", 640x480. 755 Active, color, single scan. 756 757 CONFIG_SHARP_16x9 758 759 Sharp 320x240. Active, color, single scan. 760 It isn't 16x9, and I am not sure what it is. 761 762 CONFIG_SHARP_LQ64D341 763 764 Sharp LQ64D341 display, 640x480. 765 Active, color, single scan. 766 767 CONFIG_HLD1045 768 769 HLD1045 display, 640x480. 770 Active, color, single scan. 771 772 CONFIG_OPTREX_BW 773 774 Optrex CBL50840-2 NF-FW 99 22 M5 775 or 776 Hitachi LMG6912RPFC-00T 777 or 778 Hitachi SP14Q002 779 780 320x240. Black & white. 781 782 Normally display is black on white background; define 783 CFG_WHITE_ON_BLACK to get it inverted. 784 785- Ethernet address: 786 CONFIG_ETHADDR 787 CONFIG_ETH2ADDR 788 CONFIG_ETH3ADDR 789 790 Define a default value for ethernet address to use 791 for the respective ethernet interface, in case this 792 is not determined automatically. 793 794- IP address: 795 CONFIG_IPADDR 796 797 Define a default value for the IP address to use for 798 the default ethernet interface, in case this is not 799 determined through e.g. bootp. 800 801- Server IP address: 802 CONFIG_SERVERIP 803 804 Defines a default value for theIP address of a TFTP 805 server to contact when using the "tftboot" command. 806 807- BOOTP Recovery Mode: 808 CONFIG_BOOTP_RANDOM_DELAY 809 810 If you have many targets in a network that try to 811 boot using BOOTP, you may want to avoid that all 812 systems send out BOOTP requests at precisely the same 813 moment (which would happen for instance at recovery 814 from a power failure, when all systems will try to 815 boot, thus flooding the BOOTP server. Defining 816 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 817 inserted before sending out BOOTP requests. The 818 following delays are insterted then: 819 820 1st BOOTP request: delay 0 ... 1 sec 821 2nd BOOTP request: delay 0 ... 2 sec 822 3rd BOOTP request: delay 0 ... 4 sec 823 4th and following 824 BOOTP requests: delay 0 ... 8 sec 825 826- Status LED: CONFIG_STATUS_LED 827 828 Several configurations allow to display the current 829 status using a LED. For instance, the LED will blink 830 fast while running U-Boot code, stop blinking as 831 soon as a reply to a BOOTP request was received, and 832 start blinking slow once the Linux kernel is running 833 (supported by a status LED driver in the Linux 834 kernel). Defining CONFIG_STATUS_LED enables this 835 feature in U-Boot. 836 837- CAN Support: CONFIG_CAN_DRIVER 838 839 Defining CONFIG_CAN_DRIVER enables CAN driver support 840 on those systems that support this (optional) 841 feature, like the TQM8xxL modules. 842 843- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 844 845 Enables I2C serial bus commands. If this is selected, 846 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 847 to include the appropriate I2C driver. 848 849 See also: common/cmd_i2c.c for a description of the 850 command line interface. 851 852 853 CONFIG_HARD_I2C 854 855 Selects the CPM hardware driver for I2C. 856 857 CONFIG_SOFT_I2C 858 859 Use software (aka bit-banging) driver instead of CPM 860 or similar hardware support for I2C. This is configured 861 via the following defines. 862 863 I2C_INIT 864 865 (Optional). Any commands necessary to enable I2C 866 controller or configure ports. 867 868 I2C_PORT 869 870 (Only for MPC8260 CPU). The I/O port to use (the code 871 assumes both bits are on the same port). Valid values 872 are 0..3 for ports A..D. 873 874 I2C_ACTIVE 875 876 The code necessary to make the I2C data line active 877 (driven). If the data line is open collector, this 878 define can be null. 879 880 I2C_TRISTATE 881 882 The code necessary to make the I2C data line tri-stated 883 (inactive). If the data line is open collector, this 884 define can be null. 885 886 I2C_READ 887 888 Code that returns TRUE if the I2C data line is high, 889 FALSE if it is low. 890 891 I2C_SDA(bit) 892 893 If <bit> is TRUE, sets the I2C data line high. If it 894 is FALSE, it clears it (low). 895 896 I2C_SCL(bit) 897 898 If <bit> is TRUE, sets the I2C clock line high. If it 899 is FALSE, it clears it (low). 900 901 I2C_DELAY 902 903 This delay is invoked four times per clock cycle so this 904 controls the rate of data transfer. The data rate thus 905 is 1 / (I2C_DELAY * 4). 906 907 CFG_I2C_INIT_BOARD 908 909 When a board is reset during an i2c bus transfer 910 chips might think that the current transfer is still 911 in progress. On some boards it is possible to access 912 the i2c SCLK line directly, either by using the 913 processor pin as a GPIO or by having a second pin 914 connected to the bus. If this option is defined a 915 custom i2c_init_board() routine in boards/xxx/board.c 916 is run early in the boot sequence. 917 918- SPI Support: CONFIG_SPI 919 920 Enables SPI driver (so far only tested with 921 SPI EEPROM, also an instance works with Crystal A/D and 922 D/As on the SACSng board) 923 924 CONFIG_SPI_X 925 926 Enables extended (16-bit) SPI EEPROM addressing. 927 (symmetrical to CONFIG_I2C_X) 928 929 CONFIG_SOFT_SPI 930 931 Enables a software (bit-bang) SPI driver rather than 932 using hardware support. This is a general purpose 933 driver that only requires three general I/O port pins 934 (two outputs, one input) to function. If this is 935 defined, the board configuration must define several 936 SPI configuration items (port pins to use, etc). For 937 an example, see include/configs/sacsng.h. 938 939- FPGA Support: CONFIG_FPGA_COUNT 940 941 Specify the number of FPGA devices to support. 942 943 CONFIG_FPGA 944 945 Used to specify the types of FPGA devices. For 946 example, 947 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 948 949 CFG_FPGA_PROG_FEEDBACK 950 951 Enable printing of hash marks during FPGA 952 configuration. 953 954 CFG_FPGA_CHECK_BUSY 955 956 Enable checks on FPGA configuration interface busy 957 status by the configuration function. This option 958 will require a board or device specific function to 959 be written. 960 961 CONFIG_FPGA_DELAY 962 963 If defined, a function that provides delays in the 964 FPGA configuration driver. 965 966 CFG_FPGA_CHECK_CTRLC 967 968 Allow Control-C to interrupt FPGA configuration 969 970 CFG_FPGA_CHECK_ERROR 971 972 Check for configuration errors during FPGA bitfile 973 loading. For example, abort during Virtex II 974 configuration if the INIT_B line goes low (which 975 indicated a CRC error). 976 977 CFG_FPGA_WAIT_INIT 978 979 Maximum time to wait for the INIT_B line to deassert 980 after PROB_B has been deasserted during a Virtex II 981 FPGA configuration sequence. The default time is 500 mS. 982 983 CFG_FPGA_WAIT_BUSY 984 985 Maximum time to wait for BUSY to deassert during 986 Virtex II FPGA configuration. The default is 5 mS. 987 988 CFG_FPGA_WAIT_CONFIG 989 990 Time to wait after FPGA configuration. The default is 991 200 mS. 992 993- FPGA Support: CONFIG_FPGA_COUNT 994 995 Specify the number of FPGA devices to support. 996 997 CONFIG_FPGA 998 999 Used to specify the types of FPGA devices. For example, 1000 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1001 1002 CFG_FPGA_PROG_FEEDBACK 1003 1004 Enable printing of hash marks during FPGA configuration. 1005 1006 CFG_FPGA_CHECK_BUSY 1007 1008 Enable checks on FPGA configuration interface busy 1009 status by the configuration function. This option 1010 will require a board or device specific function to 1011 be written. 1012 1013 CONFIG_FPGA_DELAY 1014 1015 If defined, a function that provides delays in the FPGA 1016 configuration driver. 1017 1018 CFG_FPGA_CHECK_CTRLC 1019 Allow Control-C to interrupt FPGA configuration 1020 1021 CFG_FPGA_CHECK_ERROR 1022 1023 Check for configuration errors during FPGA bitfile 1024 loading. For example, abort during Virtex II 1025 configuration if the INIT_B line goes low (which 1026 indicated a CRC error). 1027 1028 CFG_FPGA_WAIT_INIT 1029 1030 Maximum time to wait for the INIT_B line to deassert 1031 after PROB_B has been deasserted during a Virtex II 1032 FPGA configuration sequence. The default time is 500 1033 mS. 1034 1035 CFG_FPGA_WAIT_BUSY 1036 1037 Maximum time to wait for BUSY to deassert during 1038 Virtex II FPGA configuration. The default is 5 mS. 1039 1040 CFG_FPGA_WAIT_CONFIG 1041 1042 Time to wait after FPGA configuration. The default is 1043 200 mS. 1044 1045- Configuration Management: 1046 CONFIG_IDENT_STRING 1047 1048 If defined, this string will be added to the U-Boot 1049 version information (U_BOOT_VERSION) 1050 1051- Vendor Parameter Protection: 1052 1053 U-Boot considers the values of the environment 1054 variables "serial#" (Board Serial Number) and 1055 "ethaddr" (Ethernet Address) to bb parameters that 1056 are set once by the board vendor / manufacturer, and 1057 protects these variables from casual modification by 1058 the user. Once set, these variables are read-only, 1059 and write or delete attempts are rejected. You can 1060 change this behviour: 1061 1062 If CONFIG_ENV_OVERWRITE is #defined in your config 1063 file, the write protection for vendor parameters is 1064 completely disabled. Anybody can change or delete 1065 these parameters. 1066 1067 Alternatively, if you #define _both_ CONFIG_ETHADDR 1068 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1069 ethernet address is installed in the environment, 1070 which can be changed exactly ONCE by the user. [The 1071 serial# is unaffected by this, i. e. it remains 1072 read-only.] 1073 1074- Protected RAM: 1075 CONFIG_PRAM 1076 1077 Define this variable to enable the reservation of 1078 "protected RAM", i. e. RAM which is not overwritten 1079 by U-Boot. Define CONFIG_PRAM to hold the number of 1080 kB you want to reserve for pRAM. You can overwrite 1081 this default value by defining an environment 1082 variable "pram" to the number of kB you want to 1083 reserve. Note that the board info structure will 1084 still show the full amount of RAM. If pRAM is 1085 reserved, a new environment variable "mem" will 1086 automatically be defined to hold the amount of 1087 remaining RAM in a form that can be passed as boot 1088 argument to Linux, for instance like that: 1089 1090 setenv bootargs ... mem=\$(mem) 1091 saveenv 1092 1093 This way you can tell Linux not to use this memory, 1094 either, which results in a memory region that will 1095 not be affected by reboots. 1096 1097 *WARNING* If your board configuration uses automatic 1098 detection of the RAM size, you must make sure that 1099 this memory test is non-destructive. So far, the 1100 following board configurations are known to be 1101 "pRAM-clean": 1102 1103 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1104 HERMES, IP860, RPXlite, LWMON, LANTEC, 1105 PCU_E, FLAGADM, TQM8260 1106 1107- Error Recovery: 1108 CONFIG_PANIC_HANG 1109 1110 Define this variable to stop the system in case of a 1111 fatal error, so that you have to reset it manually. 1112 This is probably NOT a good idea for an embedded 1113 system where you want to system to reboot 1114 automatically as fast as possible, but it may be 1115 useful during development since you can try to debug 1116 the conditions that lead to the situation. 1117 1118 CONFIG_NET_RETRY_COUNT 1119 1120 This variable defines the number of retries for 1121 network operations like ARP, RARP, TFTP, or BOOTP 1122 before giving up the operation. If not defined, a 1123 default value of 5 is used. 1124 1125- Command Interpreter: 1126 CFG_HUSH_PARSER 1127 1128 Define this variable to enable the "hush" shell (from 1129 Busybox) as command line interpreter, thus enabling 1130 powerful command line syntax like 1131 if...then...else...fi conditionals or `&&' and '||' 1132 constructs ("shell scripts"). 1133 1134 If undefined, you get the old, much simpler behaviour 1135 with a somewhat smaller memory footprint. 1136 1137 1138 CFG_PROMPT_HUSH_PS2 1139 1140 This defines the secondary prompt string, which is 1141 printed when the command interpreter needs more input 1142 to complete a command. Usually "> ". 1143 1144 Note: 1145 1146 In the current implementation, the local variables 1147 space and global environment variables space are 1148 separated. Local variables are those you define by 1149 simply typing like `name=value'. To access a local 1150 variable later on, you have write `$name' or 1151 `${name}'; variable directly by typing say `$name' at 1152 the command prompt. 1153 1154 Global environment variables are those you use 1155 setenv/printenv to work with. To run a command stored 1156 in such a variable, you need to use the run command, 1157 and you must not use the '$' sign to access them. 1158 1159 To store commands and special characters in a 1160 variable, please use double quotation marks 1161 surrounding the whole text of the variable, instead 1162 of the backslashes before semicolons and special 1163 symbols. 1164 1165- Default Environment 1166 CONFIG_EXTRA_ENV_SETTINGS 1167 1168 Define this to contain any number of null terminated 1169 strings (variable = value pairs) that will be part of 1170 the default enviroment compiled into the boot image. 1171 1172 For example, place something like this in your 1173 board's config file: 1174 1175 #define CONFIG_EXTRA_ENV_SETTINGS \ 1176 "myvar1=value1\0" \ 1177 "myvar2=value2\0" 1178 1179 Warning: This method is based on knowledge about the 1180 internal format how the environment is stored by the 1181 U-Boot code. This is NOT an official, exported 1182 interface! Although it is unlikely that this format 1183 will change soon, but there is no guarantee either. 1184 You better know what you are doing here. 1185 1186 Note: overly (ab)use of the default environment is 1187 discouraged. Make sure to check other ways to preset 1188 the environment like the autoscript function or the 1189 boot command first. 1190 1191- Show boot progress 1192 CONFIG_SHOW_BOOT_PROGRESS 1193 1194 Defining this option allows to add some board- 1195 specific code (calling a user-provided function 1196 "show_boot_progress(int)") that enables you to show 1197 the system's boot progress on some display (for 1198 example, some LED's) on your board. At the moment, 1199 the following checkpoints are implemented: 1200 1201 Arg Where When 1202 1 common/cmd_bootm.c before attempting to boot an image 1203 -1 common/cmd_bootm.c Image header has bad magic number 1204 2 common/cmd_bootm.c Image header has correct magic number 1205 -2 common/cmd_bootm.c Image header has bad checksum 1206 3 common/cmd_bootm.c Image header has correct checksum 1207 -3 common/cmd_bootm.c Image data has bad checksum 1208 4 common/cmd_bootm.c Image data has correct checksum 1209 -4 common/cmd_bootm.c Image is for unsupported architecture 1210 5 common/cmd_bootm.c Architecture check OK 1211 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1212 6 common/cmd_bootm.c Image Type check OK 1213 -6 common/cmd_bootm.c gunzip uncompression error 1214 -7 common/cmd_bootm.c Unimplemented compression type 1215 7 common/cmd_bootm.c Uncompression OK 1216 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1217 8 common/cmd_bootm.c Image Type check OK 1218 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1219 9 common/cmd_bootm.c Start initial ramdisk verification 1220 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1221 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1222 10 common/cmd_bootm.c Ramdisk header is OK 1223 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1224 11 common/cmd_bootm.c Ramdisk data has correct checksum 1225 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1226 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1227 13 common/cmd_bootm.c Start multifile image verification 1228 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1229 15 common/cmd_bootm.c All preparation done, transferring control to OS 1230 1231 -1 common/cmd_doc.c Bad usage of "doc" command 1232 -1 common/cmd_doc.c No boot device 1233 -1 common/cmd_doc.c Unknown Chip ID on boot device 1234 -1 common/cmd_doc.c Read Error on boot device 1235 -1 common/cmd_doc.c Image header has bad magic number 1236 1237 -1 common/cmd_ide.c Bad usage of "ide" command 1238 -1 common/cmd_ide.c No boot device 1239 -1 common/cmd_ide.c Unknown boot device 1240 -1 common/cmd_ide.c Unknown partition table 1241 -1 common/cmd_ide.c Invalid partition type 1242 -1 common/cmd_ide.c Read Error on boot device 1243 -1 common/cmd_ide.c Image header has bad magic number 1244 1245 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1246 1247 1248Modem Support: 1249-------------- 1250 1251[so far only for SMDK2400 and TRAB boards] 1252 1253- Modem support endable: 1254 CONFIG_MODEM_SUPPORT 1255 1256- RTS/CTS Flow control enable: 1257 CONFIG_HWFLOW 1258 1259- Modem debug support: 1260 CONFIG_MODEM_SUPPORT_DEBUG 1261 1262 Enables debugging stuff (char screen[1024], dbg()) 1263 for modem support. Useful only with BDI2000. 1264 1265- General: 1266 1267 In the target system modem support is enabled when a 1268 specific key (key combination) is pressed during 1269 power-on. Otherwise U-Boot will boot normally 1270 (autoboot). The key_pressed() fuction is called from 1271 board_init(). Currently key_pressed() is a dummy 1272 function, returning 1 and thus enabling modem 1273 initialization. 1274 1275 If there are no modem init strings in the 1276 environment, U-Boot proceed to autoboot; the 1277 previous output (banner, info printfs) will be 1278 supressed, though. 1279 1280 See also: doc/README.Modem 1281 1282 1283 1284 1285Configuration Settings: 1286----------------------- 1287 1288- CFG_LONGHELP: Defined when you want long help messages included; 1289 undefine this when you're short of memory. 1290 1291- CFG_PROMPT: This is what U-Boot prints on the console to 1292 prompt for user input. 1293 1294- CFG_CBSIZE: Buffer size for input from the Console 1295 1296- CFG_PBSIZE: Buffer size for Console output 1297 1298- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1299 1300- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1301 the application (usually a Linux kernel) when it is 1302 booted 1303 1304- CFG_BAUDRATE_TABLE: 1305 List of legal baudrate settings for this board. 1306 1307- CFG_CONSOLE_INFO_QUIET 1308 Suppress display of console information at boot. 1309 1310- CFG_CONSOLE_IS_IN_ENV 1311 If the board specific function 1312 extern int overwrite_console (void); 1313 returns 1, the stdin, stderr and stdout are switched to the 1314 serial port, else the settings in the environment are used. 1315 1316- CFG_CONSOLE_OVERWRITE_ROUTINE 1317 Enable the call to overwrite_console(). 1318 1319- CFG_CONSOLE_ENV_OVERWRITE 1320 Enable overwrite of previous console environment settings. 1321 1322- CFG_MEMTEST_START, CFG_MEMTEST_END: 1323 Begin and End addresses of the area used by the 1324 simple memory test. 1325 1326- CFG_ALT_MEMTEST: 1327 Enable an alternate, more extensive memory test. 1328 1329- CFG_TFTP_LOADADDR: 1330 Default load address for network file downloads 1331 1332- CFG_LOADS_BAUD_CHANGE: 1333 Enable temporary baudrate change while serial download 1334 1335- CFG_SDRAM_BASE: 1336 Physical start address of SDRAM. _Must_ be 0 here. 1337 1338- CFG_MBIO_BASE: 1339 Physical start address of Motherboard I/O (if using a 1340 Cogent motherboard) 1341 1342- CFG_FLASH_BASE: 1343 Physical start address of Flash memory. 1344 1345- CFG_MONITOR_BASE: 1346 Physical start address of boot monitor code (set by 1347 make config files to be same as the text base address 1348 (TEXT_BASE) used when linking) - same as 1349 CFG_FLASH_BASE when booting from flash. 1350 1351- CFG_MONITOR_LEN: 1352 Size of memory reserved for monitor code 1353 1354- CFG_MALLOC_LEN: 1355 Size of DRAM reserved for malloc() use. 1356 1357- CFG_BOOTMAPSZ: 1358 Maximum size of memory mapped by the startup code of 1359 the Linux kernel; all data that must be processed by 1360 the Linux kernel (bd_info, boot arguments, eventually 1361 initrd image) must be put below this limit. 1362 1363- CFG_MAX_FLASH_BANKS: 1364 Max number of Flash memory banks 1365 1366- CFG_MAX_FLASH_SECT: 1367 Max number of sectors on a Flash chip 1368 1369- CFG_FLASH_ERASE_TOUT: 1370 Timeout for Flash erase operations (in ms) 1371 1372- CFG_FLASH_WRITE_TOUT: 1373 Timeout for Flash write operations (in ms) 1374 1375- CFG_DIRECT_FLASH_TFTP: 1376 1377 Enable TFTP transfers directly to flash memory; 1378 without this option such a download has to be 1379 performed in two steps: (1) download to RAM, and (2) 1380 copy from RAM to flash. 1381 1382 The two-step approach is usually more reliable, since 1383 you can check if the download worked before you erase 1384 the flash, but in some situations (when sytem RAM is 1385 too limited to allow for a tempory copy of the 1386 downloaded image) this option may be very useful. 1387 1388- CFG_FLASH_CFI: 1389 Define if the flash driver uses extra elements in the 1390 common flash structure for storing flash geometry 1391 1392The following definitions that deal with the placement and management 1393of environment data (variable area); in general, we support the 1394following configurations: 1395 1396- CFG_ENV_IS_IN_FLASH: 1397 1398 Define this if the environment is in flash memory. 1399 1400 a) The environment occupies one whole flash sector, which is 1401 "embedded" in the text segment with the U-Boot code. This 1402 happens usually with "bottom boot sector" or "top boot 1403 sector" type flash chips, which have several smaller 1404 sectors at the start or the end. For instance, such a 1405 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1406 such a case you would place the environment in one of the 1407 4 kB sectors - with U-Boot code before and after it. With 1408 "top boot sector" type flash chips, you would put the 1409 environment in one of the last sectors, leaving a gap 1410 between U-Boot and the environment. 1411 1412 - CFG_ENV_OFFSET: 1413 1414 Offset of environment data (variable area) to the 1415 beginning of flash memory; for instance, with bottom boot 1416 type flash chips the second sector can be used: the offset 1417 for this sector is given here. 1418 1419 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1420 1421 - CFG_ENV_ADDR: 1422 1423 This is just another way to specify the start address of 1424 the flash sector containing the environment (instead of 1425 CFG_ENV_OFFSET). 1426 1427 - CFG_ENV_SECT_SIZE: 1428 1429 Size of the sector containing the environment. 1430 1431 1432 b) Sometimes flash chips have few, equal sized, BIG sectors. 1433 In such a case you don't want to spend a whole sector for 1434 the environment. 1435 1436 - CFG_ENV_SIZE: 1437 1438 If you use this in combination with CFG_ENV_IS_IN_FLASH 1439 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1440 of this flash sector for the environment. This saves 1441 memory for the RAM copy of the environment. 1442 1443 It may also save flash memory if you decide to use this 1444 when your environment is "embedded" within U-Boot code, 1445 since then the remainder of the flash sector could be used 1446 for U-Boot code. It should be pointed out that this is 1447 STRONGLY DISCOURAGED from a robustness point of view: 1448 updating the environment in flash makes it always 1449 necessary to erase the WHOLE sector. If something goes 1450 wrong before the contents has been restored from a copy in 1451 RAM, your target system will be dead. 1452 1453 - CFG_ENV_ADDR_REDUND 1454 CFG_ENV_SIZE_REDUND 1455 1456 These settings describe a second storage area used to hold 1457 a redundand copy of the environment data, so that there is 1458 a valid backup copy in case there is a power failur during 1459 a "saveenv" operation. 1460 1461BE CAREFUL! Any changes to the flash layout, and some changes to the 1462source code will make it necessary to adapt <board>/u-boot.lds* 1463accordingly! 1464 1465 1466- CFG_ENV_IS_IN_NVRAM: 1467 1468 Define this if you have some non-volatile memory device 1469 (NVRAM, battery buffered SRAM) which you want to use for the 1470 environment. 1471 1472 - CFG_ENV_ADDR: 1473 - CFG_ENV_SIZE: 1474 1475 These two #defines are used to determin the memory area you 1476 want to use for environment. It is assumed that this memory 1477 can just be read and written to, without any special 1478 provision. 1479 1480BE CAREFUL! The first access to the environment happens quite early 1481in U-Boot initalization (when we try to get the setting of for the 1482console baudrate). You *MUST* have mappend your NVRAM area then, or 1483U-Boot will hang. 1484 1485Please note that even with NVRAM we still use a copy of the 1486environment in RAM: we could work on NVRAM directly, but we want to 1487keep settings there always unmodified except somebody uses "saveenv" 1488to save the current settings. 1489 1490 1491- CFG_ENV_IS_IN_EEPROM: 1492 1493 Use this if you have an EEPROM or similar serial access 1494 device and a driver for it. 1495 1496 - CFG_ENV_OFFSET: 1497 - CFG_ENV_SIZE: 1498 1499 These two #defines specify the offset and size of the 1500 environment area within the total memory of your EEPROM. 1501 1502 - CFG_I2C_EEPROM_ADDR: 1503 If defined, specified the chip address of the EEPROM device. 1504 The default address is zero. 1505 1506 - CFG_EEPROM_PAGE_WRITE_BITS: 1507 If defined, the number of bits used to address bytes in a 1508 single page in the EEPROM device. A 64 byte page, for example 1509 would require six bits. 1510 1511 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1512 If defined, the number of milliseconds to delay between 1513 page writes. The default is zero milliseconds. 1514 1515 - CFG_I2C_EEPROM_ADDR_LEN: 1516 The length in bytes of the EEPROM memory array address. Note 1517 that this is NOT the chip address length! 1518 1519 - CFG_EEPROM_SIZE: 1520 The size in bytes of the EEPROM device. 1521 1522 1523- CFG_SPI_INIT_OFFSET 1524 1525 Defines offset to the initial SPI buffer area in DPRAM. The 1526 area is used at an early stage (ROM part) if the environment 1527 is configured to reside in the SPI EEPROM: We need a 520 byte 1528 scratch DPRAM area. It is used between the two initialization 1529 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1530 to be a good choice since it makes it far enough from the 1531 start of the data area as well as from the stack pointer. 1532 1533Please note that the environment is read-only as long as the monitor 1534has been relocated to RAM and a RAM copy of the environment has been 1535created; also, when using EEPROM you will have to use getenv_r() 1536until then to read environment variables. 1537 1538The environment is protected by a CRC32 checksum. Before the monitor 1539is relocated into RAM, as a result of a bad CRC you will be working 1540with the compiled-in default environment - *silently*!!! [This is 1541necessary, because the first environment variable we need is the 1542"baudrate" setting for the console - if we have a bad CRC, we don't 1543have any device yet where we could complain.] 1544 1545Note: once the monitor has been relocated, then it will complain if 1546the default environment is used; a new CRC is computed as soon as you 1547use the "saveenv" command to store a valid environment. 1548 1549 1550Low Level (hardware related) configuration options: 1551--------------------------------------------------- 1552 1553- CFG_CACHELINE_SIZE: 1554 Cache Line Size of the CPU. 1555 1556- CFG_DEFAULT_IMMR: 1557 Default address of the IMMR after system reset. 1558 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1559 to be able to adjust the position of the IMMR 1560 register after a reset. 1561 1562- Floppy Disk Support: 1563 CFG_FDC_DRIVE_NUMBER 1564 1565 the default drive number (default value 0) 1566 1567 CFG_ISA_IO_STRIDE 1568 1569 defines the spacing between fdc chipset registers 1570 (default value 1) 1571 1572 CFG_ISA_IO_OFFSET 1573 1574 defines the offset of register from address. It 1575 depends on which part of the data bus is connected to 1576 the fdc chipset. (default value 0) 1577 1578 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1579 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1580 default value. 1581 1582 if CFG_FDC_HW_INIT is defined, then the function 1583 fdc_hw_init() is called at the beginning of the FDC 1584 setup. fdc_hw_init() must be provided by the board 1585 source code. It is used to make hardware dependant 1586 initializations. 1587 1588- CFG_IMMR: Physical address of the Internal Memory Mapped 1589 Register; DO NOT CHANGE! (11-4) 1590 [MPC8xx systems only] 1591 1592- CFG_INIT_RAM_ADDR: 1593 1594 Start address of memory area tha can be used for 1595 initial data and stack; please note that this must be 1596 writable memory that is working WITHOUT special 1597 initialization, i. e. you CANNOT use normal RAM which 1598 will become available only after programming the 1599 memory controller and running certain initialization 1600 sequences. 1601 1602 U-Boot uses the following memory types: 1603 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1604 - MPC824X: data cache 1605 - PPC4xx: data cache 1606 1607- CFG_GBL_DATA_OFFSET: 1608 1609 Offset of the initial data structure in the memory 1610 area defined by CFG_INIT_RAM_ADDR. Usually 1611 CFG_GBL_DATA_OFFSET is chosen such that the initial 1612 data is located at the end of the available space 1613 (sometimes written as (CFG_INIT_RAM_END - 1614 CFG_INIT_DATA_SIZE), and the initial stack is just 1615 below that area (growing from (CFG_INIT_RAM_ADDR + 1616 CFG_GBL_DATA_OFFSET) downward. 1617 1618 Note: 1619 On the MPC824X (or other systems that use the data 1620 cache for initial memory) the address chosen for 1621 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1622 point to an otherwise UNUSED address space between 1623 the top of RAM and the start of the PCI space. 1624 1625- CFG_SIUMCR: SIU Module Configuration (11-6) 1626 1627- CFG_SYPCR: System Protection Control (11-9) 1628 1629- CFG_TBSCR: Time Base Status and Control (11-26) 1630 1631- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1632 1633- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1634 1635- CFG_SCCR: System Clock and reset Control Register (15-27) 1636 1637- CFG_OR_TIMING_SDRAM: 1638 SDRAM timing 1639 1640- CFG_MAMR_PTA: 1641 periodic timer for refresh 1642 1643- CFG_DER: Debug Event Register (37-47) 1644 1645- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1646 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1647 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1648 CFG_BR1_PRELIM: 1649 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1650 1651- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1652 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1653 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1654 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1655 1656- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1657 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1658 Machine Mode Register and Memory Periodic Timer 1659 Prescaler definitions (SDRAM timing) 1660 1661- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1662 enable I2C microcode relocation patch (MPC8xx); 1663 define relocation offset in DPRAM [DSP2] 1664 1665- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1666 enable SPI microcode relocation patch (MPC8xx); 1667 define relocation offset in DPRAM [SCC4] 1668 1669- CFG_USE_OSCCLK: 1670 Use OSCM clock mode on MBX8xx board. Be careful, 1671 wrong setting might damage your board. Read 1672 doc/README.MBX before setting this variable! 1673 1674- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1675 Offset of the bootmode word in DPRAM used by post 1676 (Power On Self Tests). This definition overrides 1677 #define'd default value in commproc.h resp. 1678 cpm_8260.h. 1679 1680Building the Software: 1681====================== 1682 1683Building U-Boot has been tested in native PPC environments (on a 1684PowerBook G3 running LinuxPPC 2000) and in cross environments 1685(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1686NetBSD 1.5 on x86). 1687 1688If you are not using a native PPC environment, it is assumed that you 1689have the GNU cross compiling tools available in your path and named 1690with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1691you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1692the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1693change it to: 1694 1695 CROSS_COMPILE = ppc_4xx- 1696 1697 1698U-Boot is intended to be simple to build. After installing the 1699sources you must configure U-Boot for one specific board type. This 1700is done by typing: 1701 1702 make NAME_config 1703 1704where "NAME_config" is the name of one of the existing 1705configurations; the following names are supported: 1706 1707 ADCIOP_config GTH_config TQM850L_config 1708 ADS860_config IP860_config TQM855L_config 1709 AR405_config IVML24_config TQM860L_config 1710 CANBT_config IVMS8_config WALNUT405_config 1711 CPCI405_config LANTEC_config cogent_common_config 1712 CPCIISER4_config MBX_config cogent_mpc8260_config 1713 CU824_config MBX860T_config cogent_mpc8xx_config 1714 ESTEEM192E_config RPXlite_config hermes_config 1715 ETX094_config RPXsuper_config hymod_config 1716 FADS823_config SM850_config lwmon_config 1717 FADS850SAR_config SPD823TS_config pcu_e_config 1718 FADS860T_config SXNI855T_config rsdproto_config 1719 FPS850L_config Sandpoint8240_config sbc8260_config 1720 GENIETV_config TQM823L_config PIP405_config 1721 GEN860T_config EBONY_config FPS860L_config 1722 ELPT860_config cmi_mpc5xx_config 1723 1724Note: for some board special configuration names may exist; check if 1725 additional information is available from the board vendor; for 1726 instance, the TQM8xxL systems run normally at 50 MHz and use a 1727 SCC for 10baseT ethernet; there are also systems with 80 MHz 1728 CPU clock, and an optional Fast Ethernet module is available 1729 for CPU's with FEC. You can select such additional "features" 1730 when chosing the configuration, i. e. 1731 1732 make TQM860L_config 1733 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1734 1735 make TQM860L_FEC_config 1736 - will configure for a TQM860L at 50MHz with FEC for ethernet 1737 1738 make TQM860L_80MHz_config 1739 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1740 interface 1741 1742 make TQM860L_FEC_80MHz_config 1743 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1744 1745 make TQM823L_LCD_config 1746 - will configure for a TQM823L with U-Boot console on LCD 1747 1748 make TQM823L_LCD_80MHz_config 1749 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1750 1751 etc. 1752 1753 1754 1755Finally, type "make all", and you should get some working U-Boot 1756images ready for downlod to / installation on your system: 1757 1758- "u-boot.bin" is a raw binary image 1759- "u-boot" is an image in ELF binary format 1760- "u-boot.srec" is in Motorola S-Record format 1761 1762 1763Please be aware that the Makefiles assume you are using GNU make, so 1764for instance on NetBSD you might need to use "gmake" instead of 1765native "make". 1766 1767 1768If the system board that you have is not listed, then you will need 1769to port U-Boot to your hardware platform. To do this, follow these 1770steps: 1771 17721. Add a new configuration option for your board to the toplevel 1773 "Makefile" and to the "MAKEALL" script, using the existing 1774 entries as examples. Note that here and at many other places 1775 boards and other names are listed alphabetically sorted. Please 1776 keep this order. 17772. Create a new directory to hold your board specific code. Add any 1778 files you need. In your board directory, you will need at least 1779 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 17803. Create a new configuration file "include/configs/<board>.h" for 1781 your board 17823. If you're porting U-Boot to a new CPU, then also create a new 1783 directory to hold your CPU specific code. Add any files you need. 17844. Run "make <board>_config" with your new name. 17855. Type "make", and you should get a working "u-boot.srec" file 1786 to be installed on your target system. 17876. Debug and solve any problems that might arise. 1788 [Of course, this last step is much harder than it sounds.] 1789 1790 1791Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1792============================================================== 1793 1794If you have modified U-Boot sources (for instance added a new board 1795or support for new devices, a new CPU, etc.) you are expected to 1796provide feedback to the other developers. The feedback normally takes 1797the form of a "patch", i. e. a context diff against a certain (latest 1798official or latest in CVS) version of U-Boot sources. 1799 1800But before you submit such a patch, please verify that your modifi- 1801cation did not break existing code. At least make sure that *ALL* of 1802the supported boards compile WITHOUT ANY compiler warnings. To do so, 1803just run the "MAKEALL" script, which will configure and build U-Boot 1804for ALL supported system. Be warned, this will take a while. You can 1805select which (cross) compiler to use py passing a `CROSS_COMPILE' 1806environment variable to the script, i. e. to use the cross tools from 1807MontaVista's Hard Hat Linux you can type 1808 1809 CROSS_COMPILE=ppc_8xx- MAKEALL 1810 1811or to build on a native PowerPC system you can type 1812 1813 CROSS_COMPILE=' ' MAKEALL 1814 1815See also "U-Boot Porting Guide" below. 1816 1817 1818 1819Monitor Commands - Overview: 1820============================ 1821 1822go - start application at address 'addr' 1823run - run commands in an environment variable 1824bootm - boot application image from memory 1825bootp - boot image via network using BootP/TFTP protocol 1826tftpboot- boot image via network using TFTP protocol 1827 and env variables "ipaddr" and "serverip" 1828 (and eventually "gatewayip") 1829rarpboot- boot image via network using RARP/TFTP protocol 1830diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1831loads - load S-Record file over serial line 1832loadb - load binary file over serial line (kermit mode) 1833md - memory display 1834mm - memory modify (auto-incrementing) 1835nm - memory modify (constant address) 1836mw - memory write (fill) 1837cp - memory copy 1838cmp - memory compare 1839crc32 - checksum calculation 1840imd - i2c memory display 1841imm - i2c memory modify (auto-incrementing) 1842inm - i2c memory modify (constant address) 1843imw - i2c memory write (fill) 1844icrc32 - i2c checksum calculation 1845iprobe - probe to discover valid I2C chip addresses 1846iloop - infinite loop on address range 1847isdram - print SDRAM configuration information 1848sspi - SPI utility commands 1849base - print or set address offset 1850printenv- print environment variables 1851setenv - set environment variables 1852saveenv - save environment variables to persistent storage 1853protect - enable or disable FLASH write protection 1854erase - erase FLASH memory 1855flinfo - print FLASH memory information 1856bdinfo - print Board Info structure 1857iminfo - print header information for application image 1858coninfo - print console devices and informations 1859ide - IDE sub-system 1860loop - infinite loop on address range 1861mtest - simple RAM test 1862icache - enable or disable instruction cache 1863dcache - enable or disable data cache 1864reset - Perform RESET of the CPU 1865echo - echo args to console 1866version - print monitor version 1867help - print online help 1868? - alias for 'help' 1869 1870 1871Monitor Commands - Detailed Description: 1872======================================== 1873 1874TODO. 1875 1876For now: just type "help <command>". 1877 1878 1879Environment Variables: 1880====================== 1881 1882U-Boot supports user configuration using Environment Variables which 1883can be made persistent by saving to Flash memory. 1884 1885Environment Variables are set using "setenv", printed using 1886"printenv", and saved to Flash using "saveenv". Using "setenv" 1887without a value can be used to delete a variable from the 1888environment. As long as you don't save the environment you are 1889working with an in-memory copy. In case the Flash area containing the 1890environment is erased by accident, a default environment is provided. 1891 1892Some configuration options can be set using Environment Variables: 1893 1894 baudrate - see CONFIG_BAUDRATE 1895 1896 bootdelay - see CONFIG_BOOTDELAY 1897 1898 bootcmd - see CONFIG_BOOTCOMMAND 1899 1900 bootargs - Boot arguments when booting an RTOS image 1901 1902 bootfile - Name of the image to load with TFTP 1903 1904 autoload - if set to "no" (any string beginning with 'n'), 1905 "bootp" will just load perform a lookup of the 1906 configuration from the BOOTP server, but not try to 1907 load any image using TFTP 1908 1909 autostart - if set to "yes", an image loaded using the "bootp", 1910 "rarpboot", "tftpboot" or "diskboot" commands will 1911 be automatically started (by internally calling 1912 "bootm") 1913 1914 initrd_high - restrict positioning of initrd images: 1915 If this variable is not set, initrd images will be 1916 copied to the highest possible address in RAM; this 1917 is usually what you want since it allows for 1918 maximum initrd size. If for some reason you want to 1919 make sure that the initrd image is loaded below the 1920 CFG_BOOTMAPSZ limit, you can set this environment 1921 variable to a value of "no" or "off" or "0". 1922 Alternatively, you can set it to a maximum upper 1923 address to use (U-Boot will still check that it 1924 does not overwrite the U-Boot stack and data). 1925 1926 For instance, when you have a system with 16 MB 1927 RAM, and want to reseve 4 MB from use by Linux, 1928 you can do this by adding "mem=12M" to the value of 1929 the "bootargs" variable. However, now you must make 1930 sure, that the initrd image is placed in the first 1931 12 MB as well - this can be done with 1932 1933 setenv initrd_high 00c00000 1934 1935 ipaddr - IP address; needed for tftpboot command 1936 1937 loadaddr - Default load address for commands like "bootp", 1938 "rarpboot", "tftpboot", "loadb" or "diskboot" 1939 1940 loads_echo - see CONFIG_LOADS_ECHO 1941 1942 serverip - TFTP server IP address; needed for tftpboot command 1943 1944 bootretry - see CONFIG_BOOT_RETRY_TIME 1945 1946 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1947 1948 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1949 1950 1951The following environment variables may be used and automatically 1952updated by the network boot commands ("bootp" and "rarpboot"), 1953depending the information provided by your boot server: 1954 1955 bootfile - see above 1956 dnsip - IP address of your Domain Name Server 1957 gatewayip - IP address of the Gateway (Router) to use 1958 hostname - Target hostname 1959 ipaddr - see above 1960 netmask - Subnet Mask 1961 rootpath - Pathname of the root filesystem on the NFS server 1962 serverip - see above 1963 1964 1965There are two special Environment Variables: 1966 1967 serial# - contains hardware identification information such 1968 as type string and/or serial number 1969 ethaddr - Ethernet address 1970 1971These variables can be set only once (usually during manufacturing of 1972the board). U-Boot refuses to delete or overwrite these variables 1973once they have been set once. 1974 1975 1976Please note that changes to some configuration parameters may take 1977only effect after the next boot (yes, that's just like Windoze :-). 1978 1979 1980Note for Redundant Ethernet Interfaces: 1981======================================= 1982 1983Some boards come with redundand ethernet interfaces; U-Boot supports 1984such configurations and is capable of automatic selection of a 1985"working" interface when needed. MAC assignemnt works as follows: 1986 1987Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1988MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1989"eth1addr" (=>eth1), "eth2addr", ... 1990 1991If the network interface stores some valid MAC address (for instance 1992in SROM), this is used as default address if there is NO correspon- 1993ding setting in the environment; if the corresponding environment 1994variable is set, this overrides the settings in the card; that means: 1995 1996o If the SROM has a valid MAC address, and there is no address in the 1997 environment, the SROM's address is used. 1998 1999o If there is no valid address in the SROM, and a definition in the 2000 environment exists, then the value from the environment variable is 2001 used. 2002 2003o If both the SROM and the environment contain a MAC address, and 2004 both addresses are the same, this MAC address is used. 2005 2006o If both the SROM and the environment contain a MAC address, and the 2007 addresses differ, the value from the environment is used and a 2008 warning is printed. 2009 2010o If neither SROM nor the environment contain a MAC address, an error 2011 is raised. 2012 2013 2014 2015Image Formats: 2016============== 2017 2018The "boot" commands of this monitor operate on "image" files which 2019can be basicly anything, preceeded by a special header; see the 2020definitions in include/image.h for details; basicly, the header 2021defines the following image properties: 2022 2023* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2024 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2025 LynxOS, pSOS, QNX; 2026 Currently supported: Linux, NetBSD, VxWorks, QNX). 2027* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2028 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2029 Currently supported: PowerPC). 2030* Compression Type (Provisions for uncompressed, gzip, bzip2; 2031 Currently supported: uncompressed, gzip). 2032* Load Address 2033* Entry Point 2034* Image Name 2035* Image Timestamp 2036 2037The header is marked by a special Magic Number, and both the header 2038and the data portions of the image are secured against corruption by 2039CRC32 checksums. 2040 2041 2042Linux Support: 2043============== 2044 2045Although U-Boot should support any OS or standalone application 2046easily, Linux has always been in the focus during the design of 2047U-Boot. 2048 2049U-Boot includes many features that so far have been part of some 2050special "boot loader" code within the Linux kernel. Also, any 2051"initrd" images to be used are no longer part of one big Linux image; 2052instead, kernel and "initrd" are separate images. This implementation 2053serves serveral purposes: 2054 2055- the same features can be used for other OS or standalone 2056 applications (for instance: using compressed images to reduce the 2057 Flash memory footprint) 2058 2059- it becomes much easier to port new Linux kernel versions because 2060 lots of low-level, hardware dependend stuff are done by U-Boot 2061 2062- the same Linux kernel image can now be used with different "initrd" 2063 images; of course this also means that different kernel images can 2064 be run with the same "initrd". This makes testing easier (you don't 2065 have to build a new "zImage.initrd" Linux image when you just 2066 change a file in your "initrd"). Also, a field-upgrade of the 2067 software is easier now. 2068 2069 2070Linux HOWTO: 2071============ 2072 2073Porting Linux to U-Boot based systems: 2074--------------------------------------- 2075 2076U-Boot cannot save you from doing all the necessary modifications to 2077configure the Linux device drivers for use with your target hardware 2078(no, we don't intend to provide a full virtual machine interface to 2079Linux :-). 2080 2081But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2082 2083Just make sure your machine specific header file (for instance 2084include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2085Information structure as we define in include/u-boot.h, and make 2086sure that your definition of IMAP_ADDR uses the same value as your 2087U-Boot configuration in CFG_IMMR. 2088 2089 2090Configuring the Linux kernel: 2091----------------------------- 2092 2093No specific requirements for U-Boot. Make sure you have some root 2094device (initial ramdisk, NFS) for your target system. 2095 2096 2097Building a Linux Image: 2098----------------------- 2099 2100With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2101not used. If you use recent kernel source, a new build target 2102"uImage" will exist which automatically builds an image usable by 2103U-Boot. Most older kernels also have support for a "pImage" target, 2104which was introduced for our predecessor project PPCBoot and uses a 2105100% compatible format. 2106 2107Example: 2108 2109 make TQM850L_config 2110 make oldconfig 2111 make dep 2112 make uImage 2113 2114The "uImage" build target uses a special tool (in 'tools/mkimage') to 2115encapsulate a compressed Linux kernel image with header information, 2116CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2117 2118* build a standard "vmlinux" kernel image (in ELF binary format): 2119 2120* convert the kernel into a raw binary image: 2121 2122 ${CROSS_COMPILE}-objcopy -O binary \ 2123 -R .note -R .comment \ 2124 -S vmlinux linux.bin 2125 2126* compress the binary image: 2127 2128 gzip -9 linux.bin 2129 2130* package compressed binary image for U-Boot: 2131 2132 mkimage -A ppc -O linux -T kernel -C gzip \ 2133 -a 0 -e 0 -n "Linux Kernel Image" \ 2134 -d linux.bin.gz uImage 2135 2136 2137The "mkimage" tool can also be used to create ramdisk images for use 2138with U-Boot, either separated from the Linux kernel image, or 2139combined into one file. "mkimage" encapsulates the images with a 64 2140byte header containing information about target architecture, 2141operating system, image type, compression method, entry points, time 2142stamp, CRC32 checksums, etc. 2143 2144"mkimage" can be called in two ways: to verify existing images and 2145print the header information, or to build new images. 2146 2147In the first form (with "-l" option) mkimage lists the information 2148contained in the header of an existing U-Boot image; this includes 2149checksum verification: 2150 2151 tools/mkimage -l image 2152 -l ==> list image header information 2153 2154The second form (with "-d" option) is used to build a U-Boot image 2155from a "data file" which is used as image payload: 2156 2157 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2158 -n name -d data_file image 2159 -A ==> set architecture to 'arch' 2160 -O ==> set operating system to 'os' 2161 -T ==> set image type to 'type' 2162 -C ==> set compression type 'comp' 2163 -a ==> set load address to 'addr' (hex) 2164 -e ==> set entry point to 'ep' (hex) 2165 -n ==> set image name to 'name' 2166 -d ==> use image data from 'datafile' 2167 2168Right now, all Linux kernels use the same load address (0x00000000), 2169but the entry point address depends on the kernel version: 2170 2171- 2.2.x kernels have the entry point at 0x0000000C, 2172- 2.3.x and later kernels have the entry point at 0x00000000. 2173 2174So a typical call to build a U-Boot image would read: 2175 2176 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2177 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2178 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2179 > examples/uImage.TQM850L 2180 Image Name: 2.4.4 kernel for TQM850L 2181 Created: Wed Jul 19 02:34:59 2000 2182 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2183 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2184 Load Address: 0x00000000 2185 Entry Point: 0x00000000 2186 2187To verify the contents of the image (or check for corruption): 2188 2189 -> tools/mkimage -l examples/uImage.TQM850L 2190 Image Name: 2.4.4 kernel for TQM850L 2191 Created: Wed Jul 19 02:34:59 2000 2192 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2193 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2194 Load Address: 0x00000000 2195 Entry Point: 0x00000000 2196 2197NOTE: for embedded systems where boot time is critical you can trade 2198speed for memory and install an UNCOMPRESSED image instead: this 2199needs more space in Flash, but boots much faster since it does not 2200need to be uncompressed: 2201 2202 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2203 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2204 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2205 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2206 > examples/uImage.TQM850L-uncompressed 2207 Image Name: 2.4.4 kernel for TQM850L 2208 Created: Wed Jul 19 02:34:59 2000 2209 Image Type: PowerPC Linux Kernel Image (uncompressed) 2210 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2211 Load Address: 0x00000000 2212 Entry Point: 0x00000000 2213 2214 2215Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2216when your kernel is intended to use an initial ramdisk: 2217 2218 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2219 > -A ppc -O linux -T ramdisk -C gzip \ 2220 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2221 Image Name: Simple Ramdisk Image 2222 Created: Wed Jan 12 14:01:50 2000 2223 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2224 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2225 Load Address: 0x00000000 2226 Entry Point: 0x00000000 2227 2228 2229Installing a Linux Image: 2230------------------------- 2231 2232To downloading a U-Boot image over the serial (console) interface, 2233you must convert the image to S-Record format: 2234 2235 objcopy -I binary -O srec examples/image examples/image.srec 2236 2237The 'objcopy' does not understand the information in the U-Boot 2238image header, so the resulting S-Record file will be relative to 2239address 0x00000000. To load it to a given address, you need to 2240specify the target address as 'offset' parameter with the 'loads' 2241command. 2242 2243Example: install the image to address 0x40100000 (which on the 2244TQM8xxL is in the first Flash bank): 2245 2246 => erase 40100000 401FFFFF 2247 2248 .......... done 2249 Erased 8 sectors 2250 2251 => loads 40100000 2252 ## Ready for S-Record download ... 2253 ~>examples/image.srec 2254 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2255 ... 2256 15989 15990 15991 15992 2257 [file transfer complete] 2258 [connected] 2259 ## Start Addr = 0x00000000 2260 2261 2262You can check the success of the download using the 'iminfo' command; 2263this includes a checksum verification so you can be sure no data 2264corruption happened: 2265 2266 => imi 40100000 2267 2268 ## Checking Image at 40100000 ... 2269 Image Name: 2.2.13 for initrd on TQM850L 2270 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2271 Data Size: 335725 Bytes = 327 kB = 0 MB 2272 Load Address: 00000000 2273 Entry Point: 0000000c 2274 Verifying Checksum ... OK 2275 2276 2277 2278Boot Linux: 2279----------- 2280 2281The "bootm" command is used to boot an application that is stored in 2282memory (RAM or Flash). In case of a Linux kernel image, the contents 2283of the "bootargs" environment variable is passed to the kernel as 2284parameters. You can check and modify this variable using the 2285"printenv" and "setenv" commands: 2286 2287 2288 => printenv bootargs 2289 bootargs=root=/dev/ram 2290 2291 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2292 2293 => printenv bootargs 2294 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2295 2296 => bootm 40020000 2297 ## Booting Linux kernel at 40020000 ... 2298 Image Name: 2.2.13 for NFS on TQM850L 2299 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2300 Data Size: 381681 Bytes = 372 kB = 0 MB 2301 Load Address: 00000000 2302 Entry Point: 0000000c 2303 Verifying Checksum ... OK 2304 Uncompressing Kernel Image ... OK 2305 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 2306 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2307 time_init: decrementer frequency = 187500000/60 2308 Calibrating delay loop... 49.77 BogoMIPS 2309 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2310 ... 2311 2312If you want to boot a Linux kernel with initial ram disk, you pass 2313the memory addreses of both the kernel and the initrd image (PPBCOOT 2314format!) to the "bootm" command: 2315 2316 => imi 40100000 40200000 2317 2318 ## Checking Image at 40100000 ... 2319 Image Name: 2.2.13 for initrd on TQM850L 2320 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2321 Data Size: 335725 Bytes = 327 kB = 0 MB 2322 Load Address: 00000000 2323 Entry Point: 0000000c 2324 Verifying Checksum ... OK 2325 2326 ## Checking Image at 40200000 ... 2327 Image Name: Simple Ramdisk Image 2328 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2329 Data Size: 566530 Bytes = 553 kB = 0 MB 2330 Load Address: 00000000 2331 Entry Point: 00000000 2332 Verifying Checksum ... OK 2333 2334 => bootm 40100000 40200000 2335 ## Booting Linux kernel at 40100000 ... 2336 Image Name: 2.2.13 for initrd on TQM850L 2337 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2338 Data Size: 335725 Bytes = 327 kB = 0 MB 2339 Load Address: 00000000 2340 Entry Point: 0000000c 2341 Verifying Checksum ... OK 2342 Uncompressing Kernel Image ... OK 2343 ## Loading RAMDisk Image at 40200000 ... 2344 Image Name: Simple Ramdisk Image 2345 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2346 Data Size: 566530 Bytes = 553 kB = 0 MB 2347 Load Address: 00000000 2348 Entry Point: 00000000 2349 Verifying Checksum ... OK 2350 Loading Ramdisk ... OK 2351 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 2352 Boot arguments: root=/dev/ram 2353 time_init: decrementer frequency = 187500000/60 2354 Calibrating delay loop... 49.77 BogoMIPS 2355 ... 2356 RAMDISK: Compressed image found at block 0 2357 VFS: Mounted root (ext2 filesystem). 2358 2359 bash# 2360 2361More About U-Boot Image Types: 2362------------------------------ 2363 2364U-Boot supports the following image types: 2365 2366 "Standalone Programs" are directly runnable in the environment 2367 provided by U-Boot; it is expected that (if they behave 2368 well) you can continue to work in U-Boot after return from 2369 the Standalone Program. 2370 "OS Kernel Images" are usually images of some Embedded OS which 2371 will take over control completely. Usually these programs 2372 will install their own set of exception handlers, device 2373 drivers, set up the MMU, etc. - this means, that you cannot 2374 expect to re-enter U-Boot except by resetting the CPU. 2375 "RAMDisk Images" are more or less just data blocks, and their 2376 parameters (address, size) are passed to an OS kernel that is 2377 being started. 2378 "Multi-File Images" contain several images, typically an OS 2379 (Linux) kernel image and one or more data images like 2380 RAMDisks. This construct is useful for instance when you want 2381 to boot over the network using BOOTP etc., where the boot 2382 server provides just a single image file, but you want to get 2383 for instance an OS kernel and a RAMDisk image. 2384 2385 "Multi-File Images" start with a list of image sizes, each 2386 image size (in bytes) specified by an "uint32_t" in network 2387 byte order. This list is terminated by an "(uint32_t)0". 2388 Immediately after the terminating 0 follow the images, one by 2389 one, all aligned on "uint32_t" boundaries (size rounded up to 2390 a multiple of 4 bytes). 2391 2392 "Firmware Images" are binary images containing firmware (like 2393 U-Boot or FPGA images) which usually will be programmed to 2394 flash memory. 2395 2396 "Script files" are command sequences that will be executed by 2397 U-Boot's command interpreter; this feature is especially 2398 useful when you configure U-Boot to use a real shell (hush) 2399 as command interpreter. 2400 2401 2402Standalone HOWTO: 2403================= 2404 2405One of the features of U-Boot is that you can dynamically load and 2406run "standalone" applications, which can use some resources of 2407U-Boot like console I/O functions or interrupt services. 2408 2409Two simple examples are included with the sources: 2410 2411"Hello World" Demo: 2412------------------- 2413 2414'examples/hello_world.c' contains a small "Hello World" Demo 2415application; it is automatically compiled when you build U-Boot. 2416It's configured to run at address 0x00040004, so you can play with it 2417like that: 2418 2419 => loads 2420 ## Ready for S-Record download ... 2421 ~>examples/hello_world.srec 2422 1 2 3 4 5 6 7 8 9 10 11 ... 2423 [file transfer complete] 2424 [connected] 2425 ## Start Addr = 0x00040004 2426 2427 => go 40004 Hello World! This is a test. 2428 ## Starting application at 0x00040004 ... 2429 Hello World 2430 argc = 7 2431 argv[0] = "40004" 2432 argv[1] = "Hello" 2433 argv[2] = "World!" 2434 argv[3] = "This" 2435 argv[4] = "is" 2436 argv[5] = "a" 2437 argv[6] = "test." 2438 argv[7] = "<NULL>" 2439 Hit any key to exit ... 2440 2441 ## Application terminated, rc = 0x0 2442 2443Another example, which demonstrates how to register a CPM interrupt 2444handler with the U-Boot code, can be found in 'examples/timer.c'. 2445Here, a CPM timer is set up to generate an interrupt every second. 2446The interrupt service routine is trivial, just printing a '.' 2447character, but this is just a demo program. The application can be 2448controlled by the following keys: 2449 2450 ? - print current values og the CPM Timer registers 2451 b - enable interrupts and start timer 2452 e - stop timer and disable interrupts 2453 q - quit application 2454 2455 => loads 2456 ## Ready for S-Record download ... 2457 ~>examples/timer.srec 2458 1 2 3 4 5 6 7 8 9 10 11 ... 2459 [file transfer complete] 2460 [connected] 2461 ## Start Addr = 0x00040004 2462 2463 => go 40004 2464 ## Starting application at 0x00040004 ... 2465 TIMERS=0xfff00980 2466 Using timer 1 2467 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2468 2469Hit 'b': 2470 [q, b, e, ?] Set interval 1000000 us 2471 Enabling timer 2472Hit '?': 2473 [q, b, e, ?] ........ 2474 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2475Hit '?': 2476 [q, b, e, ?] . 2477 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2478Hit '?': 2479 [q, b, e, ?] . 2480 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2481Hit '?': 2482 [q, b, e, ?] . 2483 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2484Hit 'e': 2485 [q, b, e, ?] ...Stopping timer 2486Hit 'q': 2487 [q, b, e, ?] ## Application terminated, rc = 0x0 2488 2489 2490 2491Minicom warning: 2492================ 2493 2494Over time, many people have reported problems when trying to used the 2495"minicom" terminal emulation program for serial download. I (wd) 2496consider minicom to be broken, and recommend not to use it. Under 2497Unix, I recommend to use CKermit for general purpose use (and 2498especially for kermit binary protocol download ("loadb" command), and 2499use "cu" for S-Record download ("loads" command). 2500 2501NetBSD Notes: 2502============= 2503 2504Starting at version 0.9.2, U-Boot supports NetBSD both as host 2505(build U-Boot) and target system (boots NetBSD/mpc8xx). 2506 2507Building requires a cross environment; it is known to work on 2508NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2509need gmake since the Makefiles are not compatible with BSD make). 2510Note that the cross-powerpc package does not install include files; 2511attempting to build U-Boot will fail because <machine/ansi.h> is 2512missing. This file has to be installed and patched manually: 2513 2514 # cd /usr/pkg/cross/powerpc-netbsd/include 2515 # mkdir powerpc 2516 # ln -s powerpc machine 2517 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2518 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2519 2520Native builds *don't* work due to incompatibilities between native 2521and U-Boot include files. 2522 2523Booting assumes that (the first part of) the image booted is a 2524stage-2 loader which in turn loads and then invokes the kernel 2525proper. Loader sources will eventually appear in the NetBSD source 2526tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2527meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2528details. 2529 2530 2531Implementation Internals: 2532========================= 2533 2534The following is not intended to be a complete description of every 2535implementation detail. However, it should help to understand the 2536inner workings of U-Boot and make it easier to port it to custom 2537hardware. 2538 2539 2540Initial Stack, Global Data: 2541--------------------------- 2542 2543The implementation of U-Boot is complicated by the fact that U-Boot 2544starts running out of ROM (flash memory), usually without access to 2545system RAM (because the memory controller is not initialized yet). 2546This means that we don't have writable Data or BSS segments, and BSS 2547is not initialized as zero. To be able to get a C environment working 2548at all, we have to allocate at least a minimal stack. Implementation 2549options for this are defined and restricted by the CPU used: Some CPU 2550models provide on-chip memory (like the IMMR area on MPC8xx and 2551MPC826x processors), on others (parts of) the data cache can be 2552locked as (mis-) used as memory, etc. 2553 2554 Chris Hallinan posted a good summy of these issues to the 2555 u-boot-users mailing list: 2556 2557 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 2558 From: "Chris Hallinan" <clh@net1plus.com> 2559 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 2560 ... 2561 2562 Correct me if I'm wrong, folks, but the way I understand it 2563 is this: Using DCACHE as initial RAM for Stack, etc, does not 2564 require any physical RAM backing up the cache. The cleverness 2565 is that the cache is being used as a temporary supply of 2566 necessary storage before the SDRAM controller is setup. It's 2567 beyond the scope of this list to expain the details, but you 2568 can see how this works by studying the cache architecture and 2569 operation in the architecture and processor-specific manuals. 2570 2571 OCM is On Chip Memory, which I believe the 405GP has 4K. It 2572 is another option for the system designer to use as an 2573 initial stack/ram area prior to SDRAM being available. Either 2574 option should work for you. Using CS 4 should be fine if your 2575 board designers haven't used it for something that would 2576 cause you grief during the initial boot! It is frequently not 2577 used. 2578 2579 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 2580 with your processor/board/system design. The default value 2581 you will find in any recent u-boot distribution in 2582 Walnut405.h should work for you. I'd set it to a value larger 2583 than your SDRAM module. If you have a 64MB SDRAM module, set 2584 it above 400_0000. Just make sure your board has no resources 2585 that are supposed to respond to that address! That code in 2586 start.S has been around a while and should work as is when 2587 you get the config right. 2588 2589 -Chris Hallinan 2590 DS4.COM, Inc. 2591 2592It is essential to remember this, since it has some impact on the C 2593code for the initialization procedures: 2594 2595* Initialized global data (data segment) is read-only. Do not attempt 2596 to write it. 2597 2598* Do not use any unitialized global data (or implicitely initialized 2599 as zero data - BSS segment) at all - this is undefined, initiali- 2600 zation is performed later (when relocationg to RAM). 2601 2602* Stack space is very limited. Avoid big data buffers or things like 2603 that. 2604 2605Having only the stack as writable memory limits means we cannot use 2606normal global data to share information beween the code. But it 2607turned out that the implementation of U-Boot can be greatly 2608simplified by making a global data structure (gd_t) available to all 2609functions. We could pass a pointer to this data as argument to _all_ 2610functions, but this would bloat the code. Instead we use a feature of 2611the GCC compiler (Global Register Variables) to share the data: we 2612place a pointer (gd) to the global data into a register which we 2613reserve for this purpose. 2614 2615When chosing a register for such a purpose we are restricted by the 2616relevant (E)ABI specifications for the current architecture, and by 2617GCC's implementation. 2618 2619For PowerPC, the following registers have specific use: 2620 R1: stack pointer 2621 R2: TOC pointer 2622 R3-R4: parameter passing and return values 2623 R5-R10: parameter passing 2624 R13: small data area pointer 2625 R30: GOT pointer 2626 R31: frame pointer 2627 2628 (U-Boot also uses R14 as internal GOT pointer.) 2629 2630 ==> U-Boot will use R29 to hold a pointer to the global data 2631 2632 Note: on PPC, we could use a static initializer (since the 2633 address of the global data structure is known at compile time), 2634 but it turned out that reserving a register results in somewhat 2635 smaller code - although the code savings are not that big (on 2636 average for all boards 752 bytes for the whole U-Boot image, 2637 624 text + 127 data). 2638 2639On ARM, the following registers are used: 2640 2641 R0: function argument word/integer result 2642 R1-R3: function argument word 2643 R9: GOT pointer 2644 R10: stack limit (used only if stack checking if enabled) 2645 R11: argument (frame) pointer 2646 R12: temporary workspace 2647 R13: stack pointer 2648 R14: link register 2649 R15: program counter 2650 2651 ==> U-Boot will use R8 to hold a pointer to the global data 2652 2653 2654 2655Memory Management: 2656------------------ 2657 2658U-Boot runs in system state and uses physical addresses, i.e. the 2659MMU is not used either for address mapping nor for memory protection. 2660 2661The available memory is mapped to fixed addresses using the memory 2662controller. In this process, a contiguous block is formed for each 2663memory type (Flash, SDRAM, SRAM), even when it consists of several 2664physical memory banks. 2665 2666U-Boot is installed in the first 128 kB of the first Flash bank (on 2667TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2668booting and sizing and initializing DRAM, the code relocates itself 2669to the upper end of DRAM. Immediately below the U-Boot code some 2670memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2671configuration setting]. Below that, a structure with global Board 2672Info data is placed, followed by the stack (growing downward). 2673 2674Additionally, some exception handler code is copied to the low 8 kB 2675of DRAM (0x00000000 ... 0x00001FFF). 2676 2677So a typical memory configuration with 16 MB of DRAM could look like 2678this: 2679 2680 0x0000 0000 Exception Vector code 2681 : 2682 0x0000 1FFF 2683 0x0000 2000 Free for Application Use 2684 : 2685 : 2686 2687 : 2688 : 2689 0x00FB FF20 Monitor Stack (Growing downward) 2690 0x00FB FFAC Board Info Data and permanent copy of global data 2691 0x00FC 0000 Malloc Arena 2692 : 2693 0x00FD FFFF 2694 0x00FE 0000 RAM Copy of Monitor Code 2695 ... eventually: LCD or video framebuffer 2696 ... eventually: pRAM (Protected RAM - unchanged by reset) 2697 0x00FF FFFF [End of RAM] 2698 2699 2700System Initialization: 2701---------------------- 2702 2703In the reset configuration, U-Boot starts at the reset entry point 2704(on most PowerPC systens at address 0x00000100). Because of the reset 2705configuration for CS0# this is a mirror of the onboard Flash memory. 2706To be able to re-map memory U-Boot then jumps to it's link address. 2707To be able to implement the initialization code in C, a (small!) 2708initial stack is set up in the internal Dual Ported RAM (in case CPUs 2709which provide such a feature like MPC8xx or MPC8260), or in a locked 2710part of the data cache. After that, U-Boot initializes the CPU core, 2711the caches and the SIU. 2712 2713Next, all (potentially) available memory banks are mapped using a 2714preliminary mapping. For example, we put them on 512 MB boundaries 2715(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2716on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2717programmed for SDRAM access. Using the temporary configuration, a 2718simple memory test is run that determines the size of the SDRAM 2719banks. 2720 2721When there is more than one SDRAM bank, and the banks are of 2722different size, the larger is mapped first. For equal size, the first 2723bank (CS2#) is mapped first. The first mapping is always for address 27240x00000000, with any additional banks following immediately to create 2725contiguous memory starting from 0. 2726 2727Then, the monitor installs itself at the upper end of the SDRAM area 2728and allocates memory for use by malloc() and for the global Board 2729Info data; also, the exception vector code is copied to the low RAM 2730pages, and the final stack is set up. 2731 2732Only after this relocation will you have a "normal" C environment; 2733until that you are restricted in several ways, mostly because you are 2734running from ROM, and because the code will have to be relocated to a 2735new address in RAM. 2736 2737 2738U-Boot Porting Guide: 2739---------------------- 2740 2741[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2742list, October 2002] 2743 2744 2745int main (int argc, char *argv[]) 2746{ 2747 sighandler_t no_more_time; 2748 2749 signal (SIGALRM, no_more_time); 2750 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2751 2752 if (available_money > available_manpower) { 2753 pay consultant to port U-Boot; 2754 return 0; 2755 } 2756 2757 Download latest U-Boot source; 2758 2759 Subscribe to u-boot-users mailing list; 2760 2761 if (clueless) { 2762 email ("Hi, I am new to U-Boot, how do I get started?"); 2763 } 2764 2765 while (learning) { 2766 Read the README file in the top level directory; 2767 Read http://www.denx.de/re/DPLG.html 2768 Read the source, Luke; 2769 } 2770 2771 if (available_money > toLocalCurrency ($2500)) { 2772 Buy a BDI2000; 2773 } else { 2774 Add a lot of aggravation and time; 2775 } 2776 2777 Create your own board support subdirectory; 2778 2779 Create your own board config file; 2780 2781 while (!running) { 2782 do { 2783 Add / modify source code; 2784 } until (compiles); 2785 Debug; 2786 if (clueless) 2787 email ("Hi, I am having problems..."); 2788 } 2789 Send patch file to Wolfgang; 2790 2791 return 0; 2792} 2793 2794void no_more_time (int sig) 2795{ 2796 hire_a_guru(); 2797} 2798 2799 2800 2801Coding Standards: 2802----------------- 2803 2804All contributions to U-Boot should conform to the Linux kernel 2805coding style; see the file "Documentation/CodingStyle" in your Linux 2806kernel source directory. 2807 2808Please note that U-Boot is implemented in C (and to some small parts 2809in Assembler); no C++ is used, so please do not use C++ style 2810comments (//) in your code. 2811 2812Submissions which do not conform to the standards may be returned 2813with a request to reformat the changes. 2814 2815 2816Submitting Patches: 2817------------------- 2818 2819Since the number of patches for U-Boot is growing, we need to 2820establish some rules. Submissions which do not conform to these rules 2821may be rejected, even when they contain important and valuable stuff. 2822 2823 2824When you send a patch, please include the following information with 2825it: 2826 2827* For bug fixes: a description of the bug and how your patch fixes 2828 this bug. Please try to include a way of demonstrating that the 2829 patch actually fixes something. 2830 2831* For new features: a description of the feature and your 2832 implementation. 2833 2834* A CHANGELOG entry as plaintext (separate from the patch) 2835 2836* For major contributions, your entry to the CREDITS file 2837 2838* When you add support for a new board, don't forget to add this 2839 board to the MAKEALL script, too. 2840 2841* If your patch adds new configuration options, don't forget to 2842 document these in the README file. 2843 2844* The patch itself. If you are accessing the CVS repository use "cvs 2845 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2846 version of diff does not support these options, then get the latest 2847 version of GNU diff. 2848 2849 We accept patches as plain text, MIME attachments or as uuencoded 2850 gzipped text. 2851 2852Notes: 2853 2854* Before sending the patch, run the MAKEALL script on your patched 2855 source tree and make sure that no errors or warnings are reported 2856 for any of the boards. 2857 2858* Keep your modifications to the necessary minimum: A patch 2859 containing several unrelated changes or arbitrary reformats will be 2860 returned with a request to re-formatting / split it. 2861 2862* If you modify existing code, make sure that your new code does not 2863 add to the memory footprint of the code ;-) Small is beautiful! 2864 When adding new features, these should compile conditionally only 2865 (using #ifdef), and the resulting code with the new feature 2866 disabled must not need more memory than the old code without your 2867 modification. 2868