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/mpc8xx Files specific to Motorola MPC8xx CPUs 144- cpu/mpc824x Files specific to Motorola MPC824x CPUs 145- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 146- cpu/ppc4xx Files specific to IBM 4xx CPUs 147 148- board/RPXClassic 149 Files specific to RPXClassic boards 150- board/RPXlite Files specific to RPXlite boards 151- board/c2mon Files specific to c2mon boards 152- board/cogent Files specific to Cogent boards 153 (need further configuration) 154 Files specific to CPCIISER4 boards 155- board/cpu86 Files specific to CPU86 boards 156- board/cray/ Files specific to boards manufactured by Cray 157- board/cray/L1 Files specific to L1 boards 158- board/cu824 Files specific to CU824 boards 159- board/ebony Files specific to IBM Ebony board 160- board/eric Files specific to ERIC boards 161- board/esd/ Files specific to boards manufactured by ESD 162- board/esd/adciop Files specific to ADCIOP boards 163- board/esd/ar405 Files specific to AR405 boards 164- board/esd/canbt Files specific to CANBT boards 165- board/esd/cpci405 Files specific to CPCI405 boards 166- board/esd/cpciiser4 Files specific to CPCIISER4 boards 167- board/esd/common Common files for ESD boards 168- board/esd/dasa_sim Files specific to DASA_SIM boards 169- board/esd/du405 Files specific to DU405 boards 170- board/esd/ocrtc Files specific to OCRTC boards 171- board/esd/pci405 Files specific to PCI405 boards 172- board/esteem192e 173 Files specific to ESTEEM192E boards 174- board/etx094 Files specific to ETX_094 boards 175- board/evb64260 176 Files specific to EVB64260 boards 177- board/fads Files specific to FADS boards 178- board/flagadm Files specific to FLAGADM boards 179- board/gen860t Files specific to GEN860T boards 180- board/genietv Files specific to GENIETV boards 181- board/gth Files specific to GTH boards 182- board/hermes Files specific to HERMES boards 183- board/hymod Files specific to HYMOD boards 184- board/icu862 Files specific to ICU862 boards 185- board/ip860 Files specific to IP860 boards 186- board/iphase4539 187 Files specific to Interphase4539 boards 188- board/ivm Files specific to IVMS8/IVML24 boards 189- board/lantec Files specific to LANTEC boards 190- board/lwmon Files specific to LWMON boards 191- board/mbx8xx Files specific to MBX boards 192- board/mpc8260ads 193 Files specific to MMPC8260ADS boards 194- board/mpl/ Files specific to boards manufactured by MPL 195- board/mpl/common Common files for MPL boards 196- board/mpl/pip405 Files specific to PIP405 boards 197- board/mpl/mip405 Files specific to MIP405 boards 198- board/musenki Files specific to MUSEKNI boards 199- board/mvs1 Files specific to MVS1 boards 200- board/nx823 Files specific to NX823 boards 201- board/oxc Files specific to OXC boards 202- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 203- board/pm826 Files specific to PM826 boards 204- board/ppmc8260 205 Files specific to PPMC8260 boards 206- board/rpxsuper 207 Files specific to RPXsuper boards 208- board/rsdproto 209 Files specific to RSDproto boards 210- board/sandpoint 211 Files specific to Sandpoint boards 212- board/sbc8260 Files specific to SBC8260 boards 213- board/sacsng Files specific to SACSng boards 214- board/siemens Files specific to boards manufactured by Siemens AG 215- board/siemens/CCM Files specific to CCM boards 216- board/siemens/IAD210 Files specific to IAD210 boards 217- board/siemens/SCM Files specific to SCM boards 218- board/siemens/pcu_e Files specific to PCU_E boards 219- board/sixnet Files specific to SIXNET boards 220- board/spd8xx Files specific to SPD8xxTS boards 221- board/tqm8260 Files specific to TQM8260 boards 222- board/tqm8xx Files specific to TQM8xxL boards 223- board/w7o Files specific to W7O boards 224- board/walnut405 225 Files specific to Walnut405 boards 226- board/westel/ Files specific to boards manufactured by Westel Wireless 227- board/westel/amx860 Files specific to AMX860 boards 228- board/utx8245 Files specific to UTX8245 boards 229 230Software Configuration: 231======================= 232 233Configuration is usually done using C preprocessor defines; the 234rationale behind that is to avoid dead code whenever possible. 235 236There are two classes of configuration variables: 237 238* Configuration _OPTIONS_: 239 These are selectable by the user and have names beginning with 240 "CONFIG_". 241 242* Configuration _SETTINGS_: 243 These depend on the hardware etc. and should not be meddled with if 244 you don't know what you're doing; they have names beginning with 245 "CFG_". 246 247Later we will add a configuration tool - probably similar to or even 248identical to what's used for the Linux kernel. Right now, we have to 249do the configuration by hand, which means creating some symbolic 250links and editing some configuration files. We use the TQM8xxL boards 251as an example here. 252 253 254Selection of Processor Architecture and Board Type: 255--------------------------------------------------- 256 257For all supported boards there are ready-to-use default 258configurations available; just type "make <board_name>_config". 259 260Example: For a TQM823L module type: 261 262 cd u-boot 263 make TQM823L_config 264 265For the Cogent platform, you need to specify the cpu type as well; 266e.g. "make cogent_mpc8xx_config". And also configure the cogent 267directory according to the instructions in cogent/README. 268 269 270Configuration Options: 271---------------------- 272 273Configuration depends on the combination of board and CPU type; all 274such information is kept in a configuration file 275"include/configs/<board_name>.h". 276 277Example: For a TQM823L module, all configuration settings are in 278"include/configs/TQM823L.h". 279 280 281Many of the options are named exactly as the corresponding Linux 282kernel configuration options. The intention is to make it easier to 283build a config tool - later. 284 285 286The following options need to be configured: 287 288- CPU Type: Define exactly one of 289 290 PowerPC based CPUs: 291 ------------------- 292 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 293 or CONFIG_MPC824X, CONFIG_MPC8260 294 or CONFIG_IOP480 295 or CONFIG_405GP 296 or CONFIG_440 297 or CONFIG_MPC74xx 298 299 ARM based CPUs: 300 --------------- 301 CONFIG_SA1110 302 CONFIG_ARM7 303 CONFIG_PXA250 304 305 306- Board Type: Define exactly one of 307 308 PowerPC based boards: 309 --------------------- 310 311 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 312 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 313 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 314 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 315 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 316 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 317 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 318 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 319 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 320 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 321 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 322 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 323 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 324 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 325 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 326 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 327 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 328 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 329 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 330 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 331 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 332 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 333 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 334 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 335 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 336 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 337 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 338 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 339 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 340 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L, 341 CONFIG_V37 342 343 ARM based boards: 344 ----------------- 345 346 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 347 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 348 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 349 CONFIG_TRAB 350 351 352- CPU Module Type: (if CONFIG_COGENT is defined) 353 Define exactly one of 354 CONFIG_CMA286_60_OLD 355--- FIXME --- not tested yet: 356 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 357 CONFIG_CMA287_23, CONFIG_CMA287_50 358 359- Motherboard Type: (if CONFIG_COGENT is defined) 360 Define exactly one of 361 CONFIG_CMA101, CONFIG_CMA102 362 363- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 364 Define one or more of 365 CONFIG_CMA302 366 367- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 368 Define one or more of 369 CONFIG_LCD_HEARTBEAT - update a character position on 370 the lcd display every second with 371 a "rotator" |\-/|\-/ 372 373- MPC824X Family Member (if CONFIG_MPC824X is defined) 374 Define exactly one of 375 CONFIG_MPC8240, CONFIG_MPC8245 376 377- 8xx CPU Options: (if using an 8xx cpu) 378 Define one or more of 379 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 380 no 32KHz reference PIT/RTC clock 381 382- Clock Interface: 383 CONFIG_CLOCKS_IN_MHZ 384 385 U-Boot stores all clock information in Hz 386 internally. For binary compatibility with older Linux 387 kernels (which expect the clocks passed in the 388 bd_info data to be in MHz) the environment variable 389 "clocks_in_mhz" can be defined so that U-Boot 390 converts clock data to MHZ before passing it to the 391 Linux kernel. 392 393 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 394 "clocks_in_mhz=1" is automatically included in the 395 default environment. 396 397- Console Interface: 398 Depending on board, define exactly one serial port 399 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 400 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 401 console by defining CONFIG_8xx_CONS_NONE 402 403 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 404 port routines must be defined elsewhere 405 (i.e. serial_init(), serial_getc(), ...) 406 407 CONFIG_CFB_CONSOLE 408 Enables console device for a color framebuffer. Needs following 409 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 410 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 411 (default big endian) 412 VIDEO_HW_RECTFILL graphic chip supports 413 rectangle fill 414 (cf. smiLynxEM) 415 VIDEO_HW_BITBLT graphic chip supports 416 bit-blit (cf. smiLynxEM) 417 VIDEO_VISIBLE_COLS visible pixel columns 418 (cols=pitch) 419 VIDEO_VISIBLE_ROWS visible pixel rows 420 VIDEO_PIXEL_SIZE bytes per pixel 421 VIDEO_DATA_FORMAT graphic data format 422 (0-5, cf. cfb_console.c) 423 VIDEO_FB_ADRS framebuffer address 424 VIDEO_KBD_INIT_FCT keyboard int fct 425 (i.e. i8042_kbd_init()) 426 VIDEO_TSTC_FCT test char fct 427 (i.e. i8042_tstc) 428 VIDEO_GETC_FCT get char fct 429 (i.e. i8042_getc) 430 CONFIG_CONSOLE_CURSOR cursor drawing on/off 431 (requires blink timer 432 cf. i8042.c) 433 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 434 CONFIG_CONSOLE_TIME display time/date info in 435 upper right corner 436 (requires CFG_CMD_DATE) 437 CONFIG_VIDEO_LOGO display Linux logo in 438 upper left corner 439 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 440 linux_logo.h for logo. 441 Requires CONFIG_VIDEO_LOGO 442 CONFIG_CONSOLE_EXTRA_INFO 443 addional board info beside 444 the logo 445 446 When CONFIG_CFB_CONSOLE is defined, video console is 447 default i/o. Serial console can be forced with 448 environment 'console=serial'. 449 450- Console Baudrate: 451 CONFIG_BAUDRATE - in bps 452 Select one of the baudrates listed in 453 CFG_BAUDRATE_TABLE, see below. 454 455- Interrupt driven serial port input: 456 CONFIG_SERIAL_SOFTWARE_FIFO 457 458 PPC405GP only. 459 Use an interrupt handler for receiving data on the 460 serial port. It also enables using hardware handshake 461 (RTS/CTS) and UART's built-in FIFO. Set the number of 462 bytes the interrupt driven input buffer should have. 463 464 Set to 0 to disable this feature (this is the default). 465 This will also disable hardware handshake. 466 467- Boot Delay: CONFIG_BOOTDELAY - in seconds 468 Delay before automatically booting the default image; 469 set to -1 to disable autoboot. 470 471 See doc/README.autoboot for these options that 472 work with CONFIG_BOOTDELAY. None are required. 473 CONFIG_BOOT_RETRY_TIME 474 CONFIG_BOOT_RETRY_MIN 475 CONFIG_AUTOBOOT_KEYED 476 CONFIG_AUTOBOOT_PROMPT 477 CONFIG_AUTOBOOT_DELAY_STR 478 CONFIG_AUTOBOOT_STOP_STR 479 CONFIG_AUTOBOOT_DELAY_STR2 480 CONFIG_AUTOBOOT_STOP_STR2 481 CONFIG_ZERO_BOOTDELAY_CHECK 482 CONFIG_RESET_TO_RETRY 483 484- Autoboot Command: 485 CONFIG_BOOTCOMMAND 486 Only needed when CONFIG_BOOTDELAY is enabled; 487 define a command string that is automatically executed 488 when no character is read on the console interface 489 within "Boot Delay" after reset. 490 491 CONFIG_BOOTARGS 492 This can be used to pass arguments to the bootm 493 command. The value of CONFIG_BOOTARGS goes into the 494 environment value "bootargs". 495 496 CONFIG_RAMBOOT and CONFIG_NFSBOOT 497 The value of these goes into the environment as 498 "ramboot" and "nfsboot" respectively, and can be used 499 as a convenience, when switching between booting from 500 ram and nfs. 501 502- Pre-Boot Commands: 503 CONFIG_PREBOOT 504 505 When this option is #defined, the existence of the 506 environment variable "preboot" will be checked 507 immediately before starting the CONFIG_BOOTDELAY 508 countdown and/or running the auto-boot command resp. 509 entering interactive mode. 510 511 This feature is especially useful when "preboot" is 512 automatically generated or modified. For an example 513 see the LWMON board specific code: here "preboot" is 514 modified when the user holds down a certain 515 combination of keys on the (special) keyboard when 516 booting the systems 517 518- Serial Download Echo Mode: 519 CONFIG_LOADS_ECHO 520 If defined to 1, all characters received during a 521 serial download (using the "loads" command) are 522 echoed back. This might be needed by some terminal 523 emulations (like "cu"), but may as well just take 524 time on others. This setting #define's the initial 525 value of the "loads_echo" environment variable. 526 527- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 528 CONFIG_KGDB_BAUDRATE 529 Select one of the baudrates listed in 530 CFG_BAUDRATE_TABLE, see below. 531 532- Monitor Functions: 533 CONFIG_COMMANDS 534 Most monitor functions can be selected (or 535 de-selected) by adjusting the definition of 536 CONFIG_COMMANDS; to select individual functions, 537 #define CONFIG_COMMANDS by "OR"ing any of the 538 following values: 539 540 #define enables commands: 541 ------------------------- 542 CFG_CMD_ASKENV * ask for env variable 543 CFG_CMD_BDI bdinfo 544 CFG_CMD_BEDBUG Include BedBug Debugger 545 CFG_CMD_BOOTD bootd 546 CFG_CMD_CACHE icache, dcache 547 CFG_CMD_CONSOLE coninfo 548 CFG_CMD_DATE * support for RTC, date/time... 549 CFG_CMD_DHCP DHCP support 550 CFG_CMD_ECHO * echo arguments 551 CFG_CMD_EEPROM * EEPROM read/write support 552 CFG_CMD_ELF bootelf, bootvx 553 CFG_CMD_ENV saveenv 554 CFG_CMD_FDC * Floppy Disk Support 555 CFG_CMD_FDOS * Dos diskette Support 556 CFG_CMD_FLASH flinfo, erase, protect 557 CFG_CMD_FPGA FPGA device initialization support 558 CFG_CMD_I2C * I2C serial bus support 559 CFG_CMD_IDE * IDE harddisk support 560 CFG_CMD_IMI iminfo 561 CFG_CMD_IMMAP * IMMR dump support 562 CFG_CMD_IRQ * irqinfo 563 CFG_CMD_KGDB * kgdb 564 CFG_CMD_LOADB loadb 565 CFG_CMD_LOADS loads 566 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 567 loop, mtest 568 CFG_CMD_MII MII utility commands 569 CFG_CMD_NET bootp, tftpboot, rarpboot 570 CFG_CMD_PCI * pciinfo 571 CFG_CMD_PCMCIA * PCMCIA support 572 CFG_CMD_REGINFO * Register dump 573 CFG_CMD_RUN run command in env variable 574 CFG_CMD_SCSI * SCSI Support 575 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 576 CFG_CMD_SPI * SPI serial bus support 577 CFG_CMD_USB * USB support 578 CFG_CMD_BSP * Board SPecific functions 579 ----------------------------------------------- 580 CFG_CMD_ALL all 581 582 CFG_CMD_DFL Default configuration; at the moment 583 this is includes all commands, except 584 the ones marked with "*" in the list 585 above. 586 587 If you don't define CONFIG_COMMANDS it defaults to 588 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 589 override the default settings in the respective 590 include file. 591 592 EXAMPLE: If you want all functions except of network 593 support you can write: 594 595 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 596 597 598 Note: Don't enable the "icache" and "dcache" commands 599 (configuration option CFG_CMD_CACHE) unless you know 600 what you (and your U-Boot users) are doing. Data 601 cache cannot be enabled on systems like the 8xx or 602 8260 (where accesses to the IMMR region must be 603 uncached), and it cannot be disabled on all other 604 systems where we (mis-) use the data cache to hold an 605 initial stack and some data. 606 607 608 XXX - this list needs to get updated! 609 610- Watchdog: 611 CONFIG_WATCHDOG 612 If this variable is defined, it enables watchdog 613 support. There must support in the platform specific 614 code for a watchdog. For the 8xx and 8260 CPUs, the 615 SIU Watchdog feature is enabled in the SYPCR 616 register. 617 618- Real-Time Clock: 619 620 When CFG_CMD_DATE is selected, the type of the RTC 621 has to be selected, too. Define exactly one of the 622 following options: 623 624 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 625 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 626 CONFIG_RTC_MC146818 - use MC146818 RTC 627 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 628 629- Timestamp Support: 630 631 When CONFIG_TIMESTAMP is selected, the timestamp 632 (date and time) of an image is printed by image 633 commands like bootm or iminfo. This option is 634 automatically enabled when you select CFG_CMD_DATE . 635 636- Partition Support: 637 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 638 and/or CONFIG_ISO_PARTITION 639 640 If IDE or SCSI support is enabled (CFG_CMD_IDE or 641 CFG_CMD_SCSI) you must configure support for at least 642 one partition type as well. 643 644- IDE Reset method: 645 CONFIG_IDE_RESET_ROUTINE 646 647 Set this to define that instead of a reset Pin, the 648 routine ide_set_reset(int idereset) will be used. 649 650- ATAPI Support: 651 CONFIG_ATAPI 652 653 Set this to enable ATAPI support. 654 655- SCSI Support: 656 At the moment only there is only support for the 657 SYM53C8XX SCSI controller; define 658 CONFIG_SCSI_SYM53C8XX to enable it. 659 660 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 661 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 662 CFG_SCSI_MAX_LUN] can be adjusted to define the 663 maximum numbers of LUNs, SCSI ID's and target 664 devices. 665 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 666 667- NETWORK Support (PCI): 668 CONFIG_EEPRO100 669 Support for Intel 82557/82559/82559ER chips. 670 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 671 write routine for first time initialisation. 672 673 CONFIG_TULIP 674 Support for Digital 2114x chips. 675 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 676 modem chip initialisation (KS8761/QS6611). 677 678 CONFIG_NATSEMI 679 Support for National dp83815 chips. 680 681 CONFIG_NS8382X 682 Support for National dp8382[01] gigabit chips. 683 684- USB Support: 685 At the moment only the UHCI host controller is 686 supported (PIP405, MIP405); define 687 CONFIG_USB_UHCI to enable it. 688 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 689 end define CONFIG_USB_STORAGE to enable the USB 690 storage devices. 691 Note: 692 Supported are USB Keyboards and USB Floppy drives 693 (TEAC FD-05PUB). 694 695- Keyboard Support: 696 CONFIG_ISA_KEYBOARD 697 698 Define this to enable standard (PC-Style) keyboard 699 support 700 701 CONFIG_I8042_KBD 702 Standard PC keyboard driver with US (is default) and 703 GERMAN key layout (switch via environment 'keymap=de') support. 704 Export function i8042_kbd_init, i8042_tstc and i8042_getc 705 for cfb_console. Supports cursor blinking. 706 707- Video support: 708 CONFIG_VIDEO 709 710 Define this to enable video support (for output to 711 video). 712 713 CONFIG_VIDEO_CT69000 714 715 Enable Chips & Technologies 69000 Video chip 716 717 CONFIG_VIDEO_SMI_LYNXEM 718 Enable Silicon Motion SMI 712/710/810 Video chip 719 Videomode are selected via environment 'videomode' with 720 standard LiLo mode numbers. 721 Following modes are supported (* is default): 722 723 800x600 1024x768 1280x1024 724 256 (8bit) 303* 305 307 725 65536 (16bit) 314 317 31a 726 16,7 Mill (24bit) 315 318 31b 727 (i.e. setenv videomode 317; saveenv; reset;) 728 729 CONFIG_VIDEO_SED13806 730 Enable Epson SED13806 driver. This driver supports 8bpp 731 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 732 or CONFIG_VIDEO_SED13806_16BPP 733 734 735- LCD Support: CONFIG_LCD 736 737 Define this to enable LCD support (for output to LCD 738 display); also select one of the supported displays 739 by defining one of these: 740 741 CONFIG_NEC_NL6648AC33: 742 743 NEC NL6648AC33-18. Active, color, single scan. 744 745 CONFIG_NEC_NL6648BC20 746 747 NEC NL6648BC20-08. 6.5", 640x480. 748 Active, color, single scan. 749 750 CONFIG_SHARP_16x9 751 752 Sharp 320x240. Active, color, single scan. 753 It isn't 16x9, and I am not sure what it is. 754 755 CONFIG_SHARP_LQ64D341 756 757 Sharp LQ64D341 display, 640x480. 758 Active, color, single scan. 759 760 CONFIG_HLD1045 761 762 HLD1045 display, 640x480. 763 Active, color, single scan. 764 765 CONFIG_OPTREX_BW 766 767 Optrex CBL50840-2 NF-FW 99 22 M5 768 or 769 Hitachi LMG6912RPFC-00T 770 or 771 Hitachi SP14Q002 772 773 320x240. Black & white. 774 775 Normally display is black on white background; define 776 CFG_WHITE_ON_BLACK to get it inverted. 777 778- Ethernet address: 779 CONFIG_ETHADDR 780 CONFIG_ETH2ADDR 781 CONFIG_ETH3ADDR 782 783 Define a default value for ethernet address to use 784 for the respective ethernet interface, in case this 785 is not determined automatically. 786 787- IP address: 788 CONFIG_IPADDR 789 790 Define a default value for the IP address to use for 791 the default ethernet interface, in case this is not 792 determined through e.g. bootp. 793 794- Server IP address: 795 CONFIG_SERVERIP 796 797 Defines a default value for theIP address of a TFTP 798 server to contact when using the "tftboot" command. 799 800- BOOTP Recovery Mode: 801 CONFIG_BOOTP_RANDOM_DELAY 802 803 If you have many targets in a network that try to 804 boot using BOOTP, you may want to avoid that all 805 systems send out BOOTP requests at precisely the same 806 moment (which would happen for instance at recovery 807 from a power failure, when all systems will try to 808 boot, thus flooding the BOOTP server. Defining 809 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 810 inserted before sending out BOOTP requests. The 811 following delays are insterted then: 812 813 1st BOOTP request: delay 0 ... 1 sec 814 2nd BOOTP request: delay 0 ... 2 sec 815 3rd BOOTP request: delay 0 ... 4 sec 816 4th and following 817 BOOTP requests: delay 0 ... 8 sec 818 819- Status LED: CONFIG_STATUS_LED 820 821 Several configurations allow to display the current 822 status using a LED. For instance, the LED will blink 823 fast while running U-Boot code, stop blinking as 824 soon as a reply to a BOOTP request was received, and 825 start blinking slow once the Linux kernel is running 826 (supported by a status LED driver in the Linux 827 kernel). Defining CONFIG_STATUS_LED enables this 828 feature in U-Boot. 829 830- CAN Support: CONFIG_CAN_DRIVER 831 832 Defining CONFIG_CAN_DRIVER enables CAN driver support 833 on those systems that support this (optional) 834 feature, like the TQM8xxL modules. 835 836- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 837 838 Enables I2C serial bus commands. If this is selected, 839 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 840 to include the appropriate I2C driver. 841 842 See also: common/cmd_i2c.c for a description of the 843 command line interface. 844 845 846 CONFIG_HARD_I2C 847 848 Selects the CPM hardware driver for I2C. 849 850 CONFIG_SOFT_I2C 851 852 Use software (aka bit-banging) driver instead of CPM 853 or similar hardware support for I2C. This is configured 854 via the following defines. 855 856 I2C_INIT 857 858 (Optional). Any commands necessary to enable I2C 859 controller or configure ports. 860 861 I2C_PORT 862 863 (Only for MPC8260 CPU). The I/O port to use (the code 864 assumes both bits are on the same port). Valid values 865 are 0..3 for ports A..D. 866 867 I2C_ACTIVE 868 869 The code necessary to make the I2C data line active 870 (driven). If the data line is open collector, this 871 define can be null. 872 873 I2C_TRISTATE 874 875 The code necessary to make the I2C data line tri-stated 876 (inactive). If the data line is open collector, this 877 define can be null. 878 879 I2C_READ 880 881 Code that returns TRUE if the I2C data line is high, 882 FALSE if it is low. 883 884 I2C_SDA(bit) 885 886 If <bit> is TRUE, sets the I2C data line high. If it 887 is FALSE, it clears it (low). 888 889 I2C_SCL(bit) 890 891 If <bit> is TRUE, sets the I2C clock line high. If it 892 is FALSE, it clears it (low). 893 894 I2C_DELAY 895 896 This delay is invoked four times per clock cycle so this 897 controls the rate of data transfer. The data rate thus 898 is 1 / (I2C_DELAY * 4). 899 900- SPI Support: CONFIG_SPI 901 902 Enables SPI driver (so far only tested with 903 SPI EEPROM, also an instance works with Crystal A/D and 904 D/As on the SACSng board) 905 906 CONFIG_SPI_X 907 908 Enables extended (16-bit) SPI EEPROM addressing. 909 (symmetrical to CONFIG_I2C_X) 910 911 CONFIG_SOFT_SPI 912 913 Enables a software (bit-bang) SPI driver rather than 914 using hardware support. This is a general purpose 915 driver that only requires three general I/O port pins 916 (two outputs, one input) to function. If this is 917 defined, the board configuration must define several 918 SPI configuration items (port pins to use, etc). For 919 an example, see include/configs/sacsng.h. 920 921- FPGA Support: CONFIG_FPGA_COUNT 922 923 Specify the number of FPGA devices to support. 924 925 CONFIG_FPGA 926 927 Used to specify the types of FPGA devices. For 928 example, 929 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 930 931 CFG_FPGA_PROG_FEEDBACK 932 933 Enable printing of hash marks during FPGA 934 configuration. 935 936 CFG_FPGA_CHECK_BUSY 937 938 Enable checks on FPGA configuration interface busy 939 status by the configuration function. This option 940 will require a board or device specific function to 941 be written. 942 943 CONFIG_FPGA_DELAY 944 945 If defined, a function that provides delays in the 946 FPGA configuration driver. 947 948 CFG_FPGA_CHECK_CTRLC 949 950 Allow Control-C to interrupt FPGA configuration 951 952 CFG_FPGA_CHECK_ERROR 953 954 Check for configuration errors during FPGA bitfile 955 loading. For example, abort during Virtex II 956 configuration if the INIT_B line goes low (which 957 indicated a CRC error). 958 959 CFG_FPGA_WAIT_INIT 960 961 Maximum time to wait for the INIT_B line to deassert 962 after PROB_B has been deasserted during a Virtex II 963 FPGA configuration sequence. The default time is 500 mS. 964 965 CFG_FPGA_WAIT_BUSY 966 967 Maximum time to wait for BUSY to deassert during 968 Virtex II FPGA configuration. The default is 5 mS. 969 970 CFG_FPGA_WAIT_CONFIG 971 972 Time to wait after FPGA configuration. The default is 973 200 mS. 974 975- FPGA Support: CONFIG_FPGA_COUNT 976 977 Specify the number of FPGA devices to support. 978 979 CONFIG_FPGA 980 981 Used to specify the types of FPGA devices. For example, 982 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 983 984 CFG_FPGA_PROG_FEEDBACK 985 986 Enable printing of hash marks during FPGA configuration. 987 988 CFG_FPGA_CHECK_BUSY 989 990 Enable checks on FPGA configuration interface busy 991 status by the configuration function. This option 992 will require a board or device specific function to 993 be written. 994 995 CONFIG_FPGA_DELAY 996 997 If defined, a function that provides delays in the FPGA 998 configuration driver. 999 1000 CFG_FPGA_CHECK_CTRLC 1001 Allow Control-C to interrupt FPGA configuration 1002 1003 CFG_FPGA_CHECK_ERROR 1004 1005 Check for configuration errors during FPGA bitfile 1006 loading. For example, abort during Virtex II 1007 configuration if the INIT_B line goes low (which 1008 indicated a CRC error). 1009 1010 CFG_FPGA_WAIT_INIT 1011 1012 Maximum time to wait for the INIT_B line to deassert 1013 after PROB_B has been deasserted during a Virtex II 1014 FPGA configuration sequence. The default time is 500 1015 mS. 1016 1017 CFG_FPGA_WAIT_BUSY 1018 1019 Maximum time to wait for BUSY to deassert during 1020 Virtex II FPGA configuration. The default is 5 mS. 1021 1022 CFG_FPGA_WAIT_CONFIG 1023 1024 Time to wait after FPGA configuration. The default is 1025 200 mS. 1026 1027- Configuration Management: 1028 CONFIG_IDENT_STRING 1029 1030 If defined, this string will be added to the U-Boot 1031 version information (U_BOOT_VERSION) 1032 1033- Vendor Parameter Protection: 1034 1035 U-Boot considers the values of the environment 1036 variables "serial#" (Board Serial Number) and 1037 "ethaddr" (Ethernet Address) to bb parameters that 1038 are set once by the board vendor / manufacturer, and 1039 protects these variables from casual modification by 1040 the user. Once set, these variables are read-only, 1041 and write or delete attempts are rejected. You can 1042 change this behviour: 1043 1044 If CONFIG_ENV_OVERWRITE is #defined in your config 1045 file, the write protection for vendor parameters is 1046 completely disabled. Anybody can change or delte 1047 these parameters. 1048 1049 Alternatively, if you #define _both_ CONFIG_ETHADDR 1050 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1051 ethernet address is installed in the environment, 1052 which can be changed exactly ONCE by the user. [The 1053 serial# is unaffected by this, i. e. it remains 1054 read-only.] 1055 1056- Protected RAM: 1057 CONFIG_PRAM 1058 1059 Define this variable to enable the reservation of 1060 "protected RAM", i. e. RAM which is not overwritten 1061 by U-Boot. Define CONFIG_PRAM to hold the number of 1062 kB you want to reserve for pRAM. You can overwrite 1063 this default value by defining an environment 1064 variable "pram" to the number of kB you want to 1065 reserve. Note that the board info structure will 1066 still show the full amount of RAM. If pRAM is 1067 reserved, a new environment variable "mem" will 1068 automatically be defined to hold the amount of 1069 remaining RAM in a form that can be passed as boot 1070 argument to Linux, for instance like that: 1071 1072 setenv bootargs ... mem=\$(mem) 1073 saveenv 1074 1075 This way you can tell Linux not to use this memory, 1076 either, which results in a memory region that will 1077 not be affected by reboots. 1078 1079 *WARNING* If your board configuration uses automatic 1080 detection of the RAM size, you must make sure that 1081 this memory test is non-destructive. So far, the 1082 following board configurations are known to be 1083 "pRAM-clean": 1084 1085 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1086 HERMES, IP860, RPXlite, LWMON, LANTEC, 1087 PCU_E, FLAGADM, TQM8260 1088 1089- Error Recovery: 1090 CONFIG_PANIC_HANG 1091 1092 Define this variable to stop the system in case of a 1093 fatal error, so that you have to reset it manually. 1094 This is probably NOT a good idea for an embedded 1095 system where you want to system to reboot 1096 automatically as fast as possible, but it may be 1097 useful during development since you can try to debug 1098 the conditions that lead to the situation. 1099 1100 CONFIG_NET_RETRY_COUNT 1101 1102 This variable defines the number of retries for 1103 network operations like ARP, RARP, TFTP, or BOOTP 1104 before giving up the operation. If not defined, a 1105 default value of 5 is used. 1106 1107- Command Interpreter: 1108 CFG_HUSH_PARSER 1109 1110 Define this variable to enable the "hush" shell (from 1111 Busybox) as command line interpreter, thus enabling 1112 powerful command line syntax like 1113 if...then...else...fi conditionals or `&&' and '||' 1114 constructs ("shell scripts"). 1115 1116 If undefined, you get the old, much simpler behaviour 1117 with a somewhat smaller memory footprint. 1118 1119 1120 CFG_PROMPT_HUSH_PS2 1121 1122 This defines the secondary prompt string, which is 1123 printed when the command interpreter needs more input 1124 to complete a command. Usually "> ". 1125 1126 Note: 1127 1128 In the current implementation, the local variables 1129 space and global environment variables space are 1130 separated. Local variables are those you define by 1131 simply typing like `name=value'. To access a local 1132 variable later on, you have write `$name' or 1133 `${name}'; variable directly by typing say `$name' at 1134 the command prompt. 1135 1136 Global environment variables are those you use 1137 setenv/printenv to work with. To run a command stored 1138 in such a variable, you need to use the run command, 1139 and you must not use the '$' sign to access them. 1140 1141 To store commands and special characters in a 1142 variable, please use double quotation marks 1143 surrounding the whole text of the variable, instead 1144 of the backslashes before semicolons and special 1145 symbols. 1146 1147- Default Environment 1148 CONFIG_EXTRA_ENV_SETTINGS 1149 1150 Define this to contain any number of null terminated 1151 strings (variable = value pairs) that will be part of 1152 the default enviroment compiled into the boot image. 1153 1154 For example, place something like this in your 1155 board's config file: 1156 1157 #define CONFIG_EXTRA_ENV_SETTINGS \ 1158 "myvar1=value1\0" \ 1159 "myvar2=value2\0" 1160 1161 Warning: This method is based on knowledge about the 1162 internal format how the environment is stored by the 1163 U-Boot code. This is NOT an official, exported 1164 interface! Although it is unlikely that this format 1165 will change soon, but there is no guarantee either. 1166 You better know what you are doing here. 1167 1168 Note: overly (ab)use of the default environment is 1169 discouraged. Make sure to check other ways to preset 1170 the environment like the autoscript function or the 1171 boot command first. 1172 1173- Show boot progress 1174 CONFIG_SHOW_BOOT_PROGRESS 1175 1176 Defining this option allows to add some board- 1177 specific code (calling a user-provided function 1178 "show_boot_progress(int)") that enables you to show 1179 the system's boot progress on some display (for 1180 example, some LED's) on your board. At the moment, 1181 the following checkpoints are implemented: 1182 1183 Arg Where When 1184 1 common/cmd_bootm.c before attempting to boot an image 1185 -1 common/cmd_bootm.c Image header has bad magic number 1186 2 common/cmd_bootm.c Image header has correct magic number 1187 -2 common/cmd_bootm.c Image header has bad checksum 1188 3 common/cmd_bootm.c Image header has correct checksum 1189 -3 common/cmd_bootm.c Image data has bad checksum 1190 4 common/cmd_bootm.c Image data has correct checksum 1191 -4 common/cmd_bootm.c Image is for unsupported architecture 1192 5 common/cmd_bootm.c Architecture check OK 1193 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1194 6 common/cmd_bootm.c Image Type check OK 1195 -6 common/cmd_bootm.c gunzip uncompression error 1196 -7 common/cmd_bootm.c Unimplemented compression type 1197 7 common/cmd_bootm.c Uncompression OK 1198 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1199 8 common/cmd_bootm.c Image Type check OK 1200 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1201 9 common/cmd_bootm.c Start initial ramdisk verification 1202 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1203 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1204 10 common/cmd_bootm.c Ramdisk header is OK 1205 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1206 11 common/cmd_bootm.c Ramdisk data has correct checksum 1207 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1208 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1209 13 common/cmd_bootm.c Start multifile image verification 1210 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1211 15 common/cmd_bootm.c All preparation done, transferring control to OS 1212 1213 -1 common/cmd_doc.c Bad usage of "doc" command 1214 -1 common/cmd_doc.c No boot device 1215 -1 common/cmd_doc.c Unknown Chip ID on boot device 1216 -1 common/cmd_doc.c Read Error on boot device 1217 -1 common/cmd_doc.c Image header has bad magic number 1218 1219 -1 common/cmd_ide.c Bad usage of "ide" command 1220 -1 common/cmd_ide.c No boot device 1221 -1 common/cmd_ide.c Unknown boot device 1222 -1 common/cmd_ide.c Unknown partition table 1223 -1 common/cmd_ide.c Invalid partition type 1224 -1 common/cmd_ide.c Read Error on boot device 1225 -1 common/cmd_ide.c Image header has bad magic number 1226 1227 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1228 1229 1230Modem Support: 1231-------------- 1232 1233[so far only for SMDK2400 board] 1234 1235- Modem support endable: 1236 CONFIG_MODEM_SUPPORT 1237 1238- RTS/CTS Flow control enable: 1239 CONFIG_HWFLOW 1240 1241- Modem debug support: 1242 CONFIG_MODEM_SUPPORT_DEBUG 1243 1244 Enables debugging stuff (char screen[1024], dbg()) 1245 for modem support. Useful only with BDI2000. 1246 1247- General: 1248 1249 In the target system modem support is enabled when a 1250 specific key (key combination) is pressed during 1251 power-on. Otherwise U-Boot will boot normally 1252 (autoboot). The key_pressed() fuction is called from 1253 board_init(). Currently key_pressed() is a dummy 1254 function, returning 1 and thus enabling modem 1255 initialization. 1256 1257 If there are no modem init strings in the 1258 environment, U-Boot proceed to autoboot; the 1259 previous output (banner, info printfs) will be 1260 supressed, though. 1261 1262 See also: doc/README.Modem 1263 1264 1265 1266 1267Configuration Settings: 1268----------------------- 1269 1270- CFG_LONGHELP: Defined when you want long help messages included; 1271 undefine this when you're short of memory. 1272 1273- CFG_PROMPT: This is what U-Boot prints on the console to 1274 prompt for user input. 1275 1276- CFG_CBSIZE: Buffer size for input from the Console 1277 1278- CFG_PBSIZE: Buffer size for Console output 1279 1280- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1281 1282- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1283 the application (usually a Linux kernel) when it is 1284 booted 1285 1286- CFG_BAUDRATE_TABLE: 1287 List of legal baudrate settings for this board. 1288 1289- CFG_CONSOLE_INFO_QUIET 1290 Suppress display of console information at boot. 1291 1292- CFG_CONSOLE_IS_IN_ENV 1293 If the board specific function 1294 extern int overwrite_console (void); 1295 returns 1, the stdin, stderr and stdout are switched to the 1296 serial port, else the settings in the environment are used. 1297 1298- CFG_CONSOLE_OVERWRITE_ROUTINE 1299 Enable the call to overwrite_console(). 1300 1301- CFG_CONSOLE_ENV_OVERWRITE 1302 Enable overwrite of previous console environment settings. 1303 1304- CFG_MEMTEST_START, CFG_MEMTEST_END: 1305 Begin and End addresses of the area used by the 1306 simple memory test. 1307 1308- CFG_ALT_MEMTEST: 1309 Enable an alternate, more extensive memory test. 1310 1311- CFG_TFTP_LOADADDR: 1312 Default load address for network file downloads 1313 1314- CFG_LOADS_BAUD_CHANGE: 1315 Enable temporary baudrate change while serial download 1316 1317- CFG_SDRAM_BASE: 1318 Physical start address of SDRAM. _Must_ be 0 here. 1319 1320- CFG_MBIO_BASE: 1321 Physical start address of Motherboard I/O (if using a 1322 Cogent motherboard) 1323 1324- CFG_FLASH_BASE: 1325 Physical start address of Flash memory. 1326 1327- CFG_MONITOR_BASE: 1328 Physical start address of boot monitor code (set by 1329 make config files to be same as the text base address 1330 (TEXT_BASE) used when linking) - same as 1331 CFG_FLASH_BASE when booting from flash. 1332 1333- CFG_MONITOR_LEN: 1334 Size of memory reserved for monitor code 1335 1336- CFG_MALLOC_LEN: 1337 Size of DRAM reserved for malloc() use. 1338 1339- CFG_BOOTMAPSZ: 1340 Maximum size of memory mapped by the startup code of 1341 the Linux kernel; all data that must be processed by 1342 the Linux kernel (bd_info, boot arguments, eventually 1343 initrd image) must be put below this limit. 1344 1345- CFG_MAX_FLASH_BANKS: 1346 Max number of Flash memory banks 1347 1348- CFG_MAX_FLASH_SECT: 1349 Max number of sectors on a Flash chip 1350 1351- CFG_FLASH_ERASE_TOUT: 1352 Timeout for Flash erase operations (in ms) 1353 1354- CFG_FLASH_WRITE_TOUT: 1355 Timeout for Flash write operations (in ms) 1356 1357- CFG_DIRECT_FLASH_TFTP: 1358 1359 Enable TFTP transfers directly to flash memory; 1360 without this option such a download has to be 1361 performed in two steps: (1) download to RAM, and (2) 1362 copy from RAM to flash. 1363 1364 The two-step approach is usually more reliable, since 1365 you can check if the download worked before you erase 1366 the flash, but in some situations (when sytem RAM is 1367 too limited to allow for a tempory copy of the 1368 downloaded image) this option may be very useful. 1369 1370- CFG_FLASH_CFI: 1371 Define if the flash driver uses extra elements in the 1372 common flash structure for storing flash geometry 1373 1374The following definitions that deal with the placement and management 1375of environment data (variable area); in general, we support the 1376following configurations: 1377 1378- CFG_ENV_IS_IN_FLASH: 1379 1380 Define this if the environment is in flash memory. 1381 1382 a) The environment occupies one whole flash sector, which is 1383 "embedded" in the text segment with the U-Boot code. This 1384 happens usually with "bottom boot sector" or "top boot 1385 sector" type flash chips, which have several smaller 1386 sectors at the start or the end. For instance, such a 1387 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1388 such a case you would place the environment in one of the 1389 4 kB sectors - with U-Boot code before and after it. With 1390 "top boot sector" type flash chips, you would put the 1391 environment in one of the last sectors, leaving a gap 1392 between U-Boot and the environment. 1393 1394 - CFG_ENV_OFFSET: 1395 1396 Offset of environment data (variable area) to the 1397 beginning of flash memory; for instance, with bottom boot 1398 type flash chips the second sector can be used: the offset 1399 for this sector is given here. 1400 1401 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1402 1403 - CFG_ENV_ADDR: 1404 1405 This is just another way to specify the start address of 1406 the flash sector containing the environment (instead of 1407 CFG_ENV_OFFSET). 1408 1409 - CFG_ENV_SECT_SIZE: 1410 1411 Size of the sector containing the environment. 1412 1413 1414 b) Sometimes flash chips have few, equal sized, BIG sectors. 1415 In such a case you don't want to spend a whole sector for 1416 the environment. 1417 1418 - CFG_ENV_SIZE: 1419 1420 If you use this in combination with CFG_ENV_IS_IN_FLASH 1421 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1422 of this flash sector for the environment. This saves 1423 memory for the RAM copy of the environment. 1424 1425 It may also save flash memory if you decide to use this 1426 when your environment is "embedded" within U-Boot code, 1427 since then the remainder of the flash sector could be used 1428 for U-Boot code. It should be pointed out that this is 1429 STRONGLY DISCOURAGED from a robustness point of view: 1430 updating the environment in flash makes it always 1431 necessary to erase the WHOLE sector. If something goes 1432 wrong before the contents has been restored from a copy in 1433 RAM, your target system will be dead. 1434 1435 - CFG_ENV_ADDR_REDUND 1436 CFG_ENV_SIZE_REDUND 1437 1438 These settings describe a second storage area used to hold 1439 a redundand copy of the environment data, so that there is 1440 a valid backup copy in case there is a power failur during 1441 a "saveenv" operation. 1442 1443BE CAREFUL! Any changes to the flash layout, and some changes to the 1444source code will make it necessary to adapt <board>/u-boot.lds* 1445accordingly! 1446 1447 1448- CFG_ENV_IS_IN_NVRAM: 1449 1450 Define this if you have some non-volatile memory device 1451 (NVRAM, battery buffered SRAM) which you want to use for the 1452 environment. 1453 1454 - CFG_ENV_ADDR: 1455 - CFG_ENV_SIZE: 1456 1457 These two #defines are used to determin the memory area you 1458 want to use for environment. It is assumed that this memory 1459 can just be read and written to, without any special 1460 provision. 1461 1462BE CAREFUL! The first access to the environment happens quite early 1463in U-Boot initalization (when we try to get the setting of for the 1464console baudrate). You *MUST* have mappend your NVRAM area then, or 1465U-Boot will hang. 1466 1467Please note that even with NVRAM we still use a copy of the 1468environment in RAM: we could work on NVRAM directly, but we want to 1469keep settings there always unmodified except somebody uses "saveenv" 1470to save the current settings. 1471 1472 1473- CFG_ENV_IS_IN_EEPROM: 1474 1475 Use this if you have an EEPROM or similar serial access 1476 device and a driver for it. 1477 1478 - CFG_ENV_OFFSET: 1479 - CFG_ENV_SIZE: 1480 1481 These two #defines specify the offset and size of the 1482 environment area within the total memory of your EEPROM. 1483 1484 - CFG_I2C_EEPROM_ADDR: 1485 If defined, specified the chip address of the EEPROM device. 1486 The default address is zero. 1487 1488 - CFG_EEPROM_PAGE_WRITE_BITS: 1489 If defined, the number of bits used to address bytes in a 1490 single page in the EEPROM device. A 64 byte page, for example 1491 would require six bits. 1492 1493 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1494 If defined, the number of milliseconds to delay between 1495 page writes. The default is zero milliseconds. 1496 1497 - CFG_I2C_EEPROM_ADDR_LEN: 1498 The length in bytes of the EEPROM memory array address. Note 1499 that this is NOT the chip address length! 1500 1501 - CFG_EEPROM_SIZE: 1502 The size in bytes of the EEPROM device. 1503 1504 - CFG_I2C_EEPROM_ADDR: 1505 If defined, specified the chip address of the EEPROM device. 1506 The default address is zero. 1507 1508 - CFG_EEPROM_PAGE_WRITE_BITS: 1509 If defined, the number of bits used to address bytes in a 1510 single page in the EEPROM device. A 64 byte page, for example 1511 would require six bits. 1512 1513 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1514 If defined, the number of milliseconds to delay between 1515 page writes. The default is zero milliseconds. 1516 1517 - CFG_I2C_EEPROM_ADDR_LEN: 1518 The length in bytes of the EEPROM memory array address. Note 1519 that this is NOT the chip address length! 1520 1521 - CFG_EEPROM_SIZE: 1522 The size in bytes of the EEPROM device. 1523 1524- CFG_SPI_INIT_OFFSET 1525 1526 Defines offset to the initial SPI buffer area in DPRAM. The 1527 area is used at an early stage (ROM part) if the environment 1528 is configured to reside in the SPI EEPROM: We need a 520 byte 1529 scratch DPRAM area. It is used between the two initialization 1530 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1531 to be a good choice since it makes it far enough from the 1532 start of the data area as well as from the stack pointer. 1533 1534Please note that the environment is read-only as long as the monitor 1535has been relocated to RAM and a RAM copy of the environment has been 1536created; also, when using EEPROM you will have to use getenv_r() 1537until then to read environment variables. 1538 1539The environment is now protected by a CRC32 checksum. Before the 1540monitor is relocated into RAM, as a result of a bad CRC you will be 1541working with the compiled-in default environment - *silently*!!! 1542[This is necessary, because the first environment variable we need is 1543the "baudrate" setting for the console - if we have a bad CRC, we 1544don't have any device yet where we could complain.] 1545 1546Note: once the monitor has been relocated, then it will complain if 1547the default environment is used; a new CRC is computed as soon as you 1548use the "setenv" command to modify / delete / add any environment 1549variable [even when you try to delete a non-existing variable!]. 1550 1551Note2: you must edit your u-boot.lds file to reflect this 1552configuration. 1553 1554 1555Low Level (hardware related) configuration options: 1556 1557- CFG_CACHELINE_SIZE: 1558 Cache Line Size of the CPU. 1559 1560- CFG_DEFAULT_IMMR: 1561 Default address of the IMMR after system reset. 1562 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1563 to be able to adjust the position of the IMMR 1564 register after a reset. 1565 1566- Floppy Disk Support: 1567 CFG_FDC_DRIVE_NUMBER 1568 1569 the default drive number (default value 0) 1570 1571 CFG_ISA_IO_STRIDE 1572 1573 defines the spacing between fdc chipset registers 1574 (default value 1) 1575 1576 CFG_ISA_IO_OFFSET 1577 1578 defines the offset of register from address. It 1579 depends on which part of the data bus is connected to 1580 the fdc chipset. (default value 0) 1581 1582 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1583 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1584 default value. 1585 1586 if CFG_FDC_HW_INIT is defined, then the function 1587 fdc_hw_init() is called at the beginning of the FDC 1588 setup. fdc_hw_init() must be provided by the board 1589 source code. It is used to make hardware dependant 1590 initializations. 1591 1592- CFG_IMMR: Physical address of the Internal Memory Mapped 1593 Register; DO NOT CHANGE! (11-4) 1594 [MPC8xx systems only] 1595 1596- CFG_INIT_RAM_ADDR: 1597 1598 Start address of memory area tha can be used for 1599 initial data and stack; please note that this must be 1600 writable memory that is working WITHOUT special 1601 initialization, i. e. you CANNOT use normal RAM which 1602 will become available only after programming the 1603 memory controller and running certain initialization 1604 sequences. 1605 1606 U-Boot uses the following memory types: 1607 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1608 - MPC824X: data cache 1609 - PPC4xx: data cache 1610 1611- CFG_INIT_DATA_OFFSET: 1612 1613 Offset of the initial data structure in the memory 1614 area defined by CFG_INIT_RAM_ADDR. Usually 1615 CFG_INIT_DATA_OFFSET is chosen such that the initial 1616 data is located at the end of the available space 1617 (sometimes written as (CFG_INIT_RAM_END - 1618 CFG_INIT_DATA_SIZE), and the initial stack is just 1619 below that area (growing from (CFG_INIT_RAM_ADDR + 1620 CFG_INIT_DATA_OFFSET) downward. 1621 1622 Note: 1623 On the MPC824X (or other systems that use the data 1624 cache for initial memory) the address chosen for 1625 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1626 point to an otherwise UNUSED address space between 1627 the top of RAM and the start of the PCI space. 1628 1629- CFG_SIUMCR: SIU Module Configuration (11-6) 1630 1631- CFG_SYPCR: System Protection Control (11-9) 1632 1633- CFG_TBSCR: Time Base Status and Control (11-26) 1634 1635- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1636 1637- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1638 1639- CFG_SCCR: System Clock and reset Control Register (15-27) 1640 1641- CFG_OR_TIMING_SDRAM: 1642 SDRAM timing 1643 1644- CFG_MAMR_PTA: 1645 periodic timer for refresh 1646 1647- CFG_DER: Debug Event Register (37-47) 1648 1649- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1650 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1651 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1652 CFG_BR1_PRELIM: 1653 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1654 1655- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1656 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1657 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1658 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1659 1660- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1661 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1662 Machine Mode Register and Memory Periodic Timer 1663 Prescaler definitions (SDRAM timing) 1664 1665- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1666 enable I2C microcode relocation patch (MPC8xx); 1667 define relocation offset in DPRAM [DSP2] 1668 1669- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1670 enable SPI microcode relocation patch (MPC8xx); 1671 define relocation offset in DPRAM [SCC4] 1672 1673- CFG_USE_OSCCLK: 1674 Use OSCM clock mode on MBX8xx board. Be careful, 1675 wrong setting might damage your board. Read 1676 doc/README.MBX before setting this variable! 1677 1678- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1679 Offset of the bootmode word in DPRAM used by post 1680 (Power On Self Tests). This definition overrides 1681 #define'd default value in commproc.h resp. 1682 cpm_8260.h. 1683 1684Building the Software: 1685====================== 1686 1687Building U-Boot has been tested in native PPC environments (on a 1688PowerBook G3 running LinuxPPC 2000) and in cross environments 1689(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1690NetBSD 1.5 on x86). 1691 1692If you are not using a native PPC environment, it is assumed that you 1693have the GNU cross compiling tools available in your path and named 1694with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1695you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1696the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1697change it to: 1698 1699 CROSS_COMPILE = ppc_4xx- 1700 1701 1702U-Boot is intended to be simple to build. After installing the 1703sources you must configure U-Boot for one specific board type. This 1704is done by typing: 1705 1706 make NAME_config 1707 1708where "NAME_config" is the name of one of the existing 1709configurations; the following names are supported: 1710 1711 ADCIOP_config GTH_config TQM850L_config 1712 ADS860_config IP860_config TQM855L_config 1713 AR405_config IVML24_config TQM860L_config 1714 CANBT_config IVMS8_config WALNUT405_config 1715 CPCI405_config LANTEC_config cogent_common_config 1716 CPCIISER4_config MBX_config cogent_mpc8260_config 1717 CU824_config MBX860T_config cogent_mpc8xx_config 1718 ESTEEM192E_config RPXlite_config hermes_config 1719 ETX094_config RPXsuper_config hymod_config 1720 FADS823_config SM850_config lwmon_config 1721 FADS850SAR_config SPD823TS_config pcu_e_config 1722 FADS860T_config SXNI855T_config rsdproto_config 1723 FPS850L_config Sandpoint8240_config sbc8260_config 1724 GENIETV_config TQM823L_config PIP405_config 1725 GEN860T_config EBONY_config FPS860L_config 1726 1727Note: for some board special configuration names may exist; check if 1728 additional information is available from the board vendor; for 1729 instance, the TQM8xxL systems run normally at 50 MHz and use a 1730 SCC for 10baseT ethernet; there are also systems with 80 MHz 1731 CPU clock, and an optional Fast Ethernet module is available 1732 for CPU's with FEC. You can select such additional "features" 1733 when chosing the configuration, i. e. 1734 1735 make TQM860L_config 1736 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1737 1738 make TQM860L_FEC_config 1739 - will configure for a TQM860L at 50MHz with FEC for ethernet 1740 1741 make TQM860L_80MHz_config 1742 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1743 interface 1744 1745 make TQM860L_FEC_80MHz_config 1746 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1747 1748 make TQM823L_LCD_config 1749 - will configure for a TQM823L with U-Boot console on LCD 1750 1751 make TQM823L_LCD_80MHz_config 1752 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1753 1754 etc. 1755 1756 1757 1758Finally, type "make all", and you should get some working U-Boot 1759images ready for downlod to / installation on your system: 1760 1761- "u-boot.bin" is a raw binary image 1762- "u-boot" is an image in ELF binary format 1763- "u-boot.srec" is in Motorola S-Record format 1764 1765 1766Please be aware that the Makefiles assume you are using GNU make, so 1767for instance on NetBSD you might need to use "gmake" instead of 1768native "make". 1769 1770 1771If the system board that you have is not listed, then you will need 1772to port U-Boot to your hardware platform. To do this, follow these 1773steps: 1774 17751. Add a new configuration option for your board to the toplevel 1776 "Makefile", using the existing entries as examples. 17772. Create a new directory to hold your board specific code. Add any 1778 files you need. 17793. If you're porting U-Boot to a new CPU, then also create a new 1780 directory to hold your CPU specific code. Add any files you need. 17814. Run "make config_name" with your new name. 17825. Type "make", and you should get a working "u-boot.srec" file 1783 to be installed on your target system. 1784 [Of course, this last step is much harder than it sounds.] 1785 1786 1787Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1788============================================================== 1789 1790If you have modified U-Boot sources (for instance added a new board 1791or support for new devices, a new CPU, etc.) you are expected to 1792provide feedback to the other developers. The feedback normally takes 1793the form of a "patch", i. e. a context diff against a certain (latest 1794official or latest in CVS) version of U-Boot sources. 1795 1796But before you submit such a patch, please verify that your modifi- 1797cation did not break existing code. At least make sure that *ALL* of 1798the supported boards compile WITHOUT ANY compiler warnings. To do so, 1799just run the "MAKEALL" script, which will configure and build U-Boot 1800for ALL supported system. Be warned, this will take a while. You can 1801select which (cross) compiler to use py passing a `CROSS_COMPILE' 1802environment variable to the script, i. e. to use the cross tools from 1803MontaVista's Hard Hat Linux you can type 1804 1805 CROSS_COMPILE=ppc_8xx- MAKEALL 1806 1807or to build on a native PowerPC system you can type 1808 1809 CROSS_COMPILE=' ' MAKEALL 1810 1811See also "U-Boot Porting Guide" below. 1812 1813 1814 1815Monitor Commands - Overview: 1816============================ 1817 1818go - start application at address 'addr' 1819run - run commands in an environment variable 1820bootm - boot application image from memory 1821bootp - boot image via network using BootP/TFTP protocol 1822tftpboot- boot image via network using TFTP protocol 1823 and env variables "ipaddr" and "serverip" 1824 (and eventually "gatewayip") 1825rarpboot- boot image via network using RARP/TFTP protocol 1826diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1827loads - load S-Record file over serial line 1828loadb - load binary file over serial line (kermit mode) 1829md - memory display 1830mm - memory modify (auto-incrementing) 1831nm - memory modify (constant address) 1832mw - memory write (fill) 1833cp - memory copy 1834cmp - memory compare 1835crc32 - checksum calculation 1836imd - i2c memory display 1837imm - i2c memory modify (auto-incrementing) 1838inm - i2c memory modify (constant address) 1839imw - i2c memory write (fill) 1840icrc32 - i2c checksum calculation 1841iprobe - probe to discover valid I2C chip addresses 1842iloop - infinite loop on address range 1843isdram - print SDRAM configuration information 1844sspi - SPI utility commands 1845base - print or set address offset 1846printenv- print environment variables 1847setenv - set environment variables 1848saveenv - save environment variables to persistent storage 1849protect - enable or disable FLASH write protection 1850erase - erase FLASH memory 1851flinfo - print FLASH memory information 1852bdinfo - print Board Info structure 1853iminfo - print header information for application image 1854coninfo - print console devices and informations 1855ide - IDE sub-system 1856loop - infinite loop on address range 1857mtest - simple RAM test 1858icache - enable or disable instruction cache 1859dcache - enable or disable data cache 1860reset - Perform RESET of the CPU 1861echo - echo args to console 1862version - print monitor version 1863help - print online help 1864? - alias for 'help' 1865 1866 1867Monitor Commands - Detailed Description: 1868======================================== 1869 1870TODO. 1871 1872For now: just type "help <command>". 1873 1874 1875Environment Variables: 1876====================== 1877 1878U-Boot supports user configuration using Environment Variables which 1879can be made persistent by saving to Flash memory. 1880 1881Environment Variables are set using "setenv", printed using 1882"printenv", and saved to Flash using "saveenv". Using "setenv" 1883without a value can be used to delete a variable from the 1884environment. As long as you don't save the environment you are 1885working with an in-memory copy. In case the Flash area containing the 1886environment is erased by accident, a default environment is provided. 1887 1888Some configuration options can be set using Environment Variables: 1889 1890 baudrate - see CONFIG_BAUDRATE 1891 1892 bootdelay - see CONFIG_BOOTDELAY 1893 1894 bootcmd - see CONFIG_BOOTCOMMAND 1895 1896 bootargs - Boot arguments when booting an RTOS image 1897 1898 bootfile - Name of the image to load with TFTP 1899 1900 autoload - if set to "no" (any string beginning with 'n'), 1901 "bootp" will just load perform a lookup of the 1902 configuration from the BOOTP server, but not try to 1903 load any image using TFTP 1904 1905 autostart - if set to "yes", an image loaded using the "bootp", 1906 "rarpboot", "tftpboot" or "diskboot" commands will 1907 be automatically started (by internally calling 1908 "bootm") 1909 1910 initrd_high - restrict positioning of initrd images: 1911 If this variable is not set, initrd images will be 1912 copied to the highest possible address in RAM; this 1913 is usually what you want since it allows for 1914 maximum initrd size. If for some reason you want to 1915 make sure that the initrd image is loaded below the 1916 CFG_BOOTMAPSZ limit, you can set this environment 1917 variable to a value of "no" or "off" or "0". 1918 Alternatively, you can set it to a maximum upper 1919 address to use (U-Boot will still check that it 1920 does not overwrite the U-Boot stack and data). 1921 1922 For instance, when you have a system with 16 MB 1923 RAM, and want to reseve 4 MB from use by Linux, 1924 you can do this by adding "mem=12M" to the value of 1925 the "bootargs" variable. However, now you must make 1926 sure, that the initrd image is placed in the first 1927 12 MB as well - this can be done with 1928 1929 setenv initrd_high 00c00000 1930 1931 ipaddr - IP address; needed for tftpboot command 1932 1933 loadaddr - Default load address for commands like "bootp", 1934 "rarpboot", "tftpboot" or "diskboot" 1935 1936 loads_echo - see CONFIG_LOADS_ECHO 1937 1938 serverip - TFTP server IP address; needed for tftpboot command 1939 1940 bootretry - see CONFIG_BOOT_RETRY_TIME 1941 1942 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1943 1944 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1945 1946 1947The following environment variables may be used and automatically 1948updated by the network boot commands ("bootp" and "rarpboot"), 1949depending the information provided by your boot server: 1950 1951 bootfile - see above 1952 dnsip - IP address of your Domain Name Server 1953 gatewayip - IP address of the Gateway (Router) to use 1954 hostname - Target hostname 1955 ipaddr - see above 1956 netmask - Subnet Mask 1957 rootpath - Pathname of the root filesystem on the NFS server 1958 serverip - see above 1959 1960 1961There are two special Environment Variables: 1962 1963 serial# - contains hardware identification information such 1964 as type string and/or serial number 1965 ethaddr - Ethernet address 1966 1967These variables can be set only once (usually during manufacturing of 1968the board). U-Boot refuses to delete or overwrite these variables 1969once they have been set once. 1970 1971 1972Please note that changes to some configuration parameters may take 1973only effect after the next boot (yes, that's just like Windoze :-). 1974 1975 1976Note for Redundant Ethernet Interfaces: 1977======================================= 1978 1979Some boards come with redundand ethernet interfaces; U-Boot supports 1980such configurations and is capable of automatic selection of a 1981"working" interface when needed. MAC assignemnt works as follows: 1982 1983Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1984MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1985"eth1addr" (=>eth1), "eth2addr", ... 1986 1987If the network interface stores some valid MAC address (for instance 1988in SROM), this is used as default address if there is NO correspon- 1989ding setting in the environment; if the corresponding environment 1990variable is set, this overrides the settings in the card; that means: 1991 1992o If the SROM has a valid MAC address, and there is no address in the 1993 environment, the SROM's address is used. 1994 1995o If there is no valid address in the SROM, and a definition in the 1996 environment exists, then the value from the environment variable is 1997 used. 1998 1999o If both the SROM and the environment contain a MAC address, and 2000 both addresses are the same, this MAC address is used. 2001 2002o If both the SROM and the environment contain a MAC address, and the 2003 addresses differ, the value from the environment is used and a 2004 warning is printed. 2005 2006o If neither SROM nor the environment contain a MAC address, an error 2007 is raised. 2008 2009 2010 2011Image Formats: 2012============== 2013 2014The "boot" commands of this monitor operate on "image" files which 2015can be basicly anything, preceeded by a special header; see the 2016definitions in include/image.h for details; basicly, the header 2017defines the following image properties: 2018 2019* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2020 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2021 LynxOS, pSOS, QNX; 2022 Currently supported: Linux, NetBSD, VxWorks, QNX). 2023* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2024 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2025 Currently supported: PowerPC). 2026* Compression Type (Provisions for uncompressed, gzip, bzip2; 2027 Currently supported: uncompressed, gzip). 2028* Load Address 2029* Entry Point 2030* Image Name 2031* Image Timestamp 2032 2033The header is marked by a special Magic Number, and both the header 2034and the data portions of the image are secured against corruption by 2035CRC32 checksums. 2036 2037 2038Linux Support: 2039============== 2040 2041Although U-Boot should support any OS or standalone application 2042easily, Linux has always been in the focus during the design of 2043U-Boot. 2044 2045U-Boot includes many features that so far have been part of some 2046special "boot loader" code within the Linux kernel. Also, any 2047"initrd" images to be used are no longer part of one big Linux image; 2048instead, kernel and "initrd" are separate images. This implementation 2049serves serveral purposes: 2050 2051- the same features can be used for other OS or standalone 2052 applications (for instance: using compressed images to reduce the 2053 Flash memory footprint) 2054 2055- it becomes much easier to port new Linux kernel versions because 2056 lots of low-level, hardware dependend stuff are done by U-Boot 2057 2058- the same Linux kernel image can now be used with different "initrd" 2059 images; of course this also means that different kernel images can 2060 be run with the same "initrd". This makes testing easier (you don't 2061 have to build a new "zImage.initrd" Linux image when you just 2062 change a file in your "initrd"). Also, a field-upgrade of the 2063 software is easier now. 2064 2065 2066Linux HOWTO: 2067============ 2068 2069Porting Linux to U-Boot based systems: 2070--------------------------------------- 2071 2072U-Boot cannot save you from doing all the necessary modifications to 2073configure the Linux device drivers for use with your target hardware 2074(no, we don't intend to provide a full virtual machine interface to 2075Linux :-). 2076 2077But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2078 2079Just make sure your machine specific header file (for instance 2080include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2081Information structure as we define in include/u-boot.h, and make 2082sure that your definition of IMAP_ADDR uses the same value as your 2083U-Boot configuration in CFG_IMMR. 2084 2085 2086Configuring the Linux kernel: 2087----------------------------- 2088 2089No specific requirements for U-Boot. Make sure you have some root 2090device (initial ramdisk, NFS) for your target system. 2091 2092 2093Building a Linux Image: 2094----------------------- 2095 2096With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2097not used. If you use recent kernel source, a new build target 2098"uImage" will exist which automatically builds an image usable by 2099U-Boot. Most older kernels also have support for a "pImage" target, 2100which was introduced for our predecessor project PPCBoot and uses a 2101100% compatible format. 2102 2103Example: 2104 2105 make TQM850L_config 2106 make oldconfig 2107 make dep 2108 make uImage 2109 2110The "uImage" build target uses a special tool (in 'tools/mkimage') to 2111encapsulate a compressed Linux kernel image with header information, 2112CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2113 2114* build a standard "vmlinux" kernel image (in ELF binary format): 2115 2116* convert the kernel into a raw binary image: 2117 2118 ${CROSS_COMPILE}-objcopy -O binary \ 2119 -R .note -R .comment \ 2120 -S vmlinux linux.bin 2121 2122* compress the binary image: 2123 2124 gzip -9 linux.bin 2125 2126* package compressed binary image for U-Boot: 2127 2128 mkimage -A ppc -O linux -T kernel -C gzip \ 2129 -a 0 -e 0 -n "Linux Kernel Image" \ 2130 -d linux.bin.gz uImage 2131 2132 2133The "mkimage" tool can also be used to create ramdisk images for use 2134with U-Boot, either separated from the Linux kernel image, or 2135combined into one file. "mkimage" encapsulates the images with a 64 2136byte header containing information about target architecture, 2137operating system, image type, compression method, entry points, time 2138stamp, CRC32 checksums, etc. 2139 2140"mkimage" can be called in two ways: to verify existing images and 2141print the header information, or to build new images. 2142 2143In the first form (with "-l" option) mkimage lists the information 2144contained in the header of an existing U-Boot image; this includes 2145checksum verification: 2146 2147 tools/mkimage -l image 2148 -l ==> list image header information 2149 2150The second form (with "-d" option) is used to build a U-Boot image 2151from a "data file" which is used as image payload: 2152 2153 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2154 -n name -d data_file image 2155 -A ==> set architecture to 'arch' 2156 -O ==> set operating system to 'os' 2157 -T ==> set image type to 'type' 2158 -C ==> set compression type 'comp' 2159 -a ==> set load address to 'addr' (hex) 2160 -e ==> set entry point to 'ep' (hex) 2161 -n ==> set image name to 'name' 2162 -d ==> use image data from 'datafile' 2163 2164Right now, all Linux kernels use the same load address (0x00000000), 2165but the entry point address depends on the kernel version: 2166 2167- 2.2.x kernels have the entry point at 0x0000000C, 2168- 2.3.x and later kernels have the entry point at 0x00000000. 2169 2170So a typical call to build a U-Boot image would read: 2171 2172 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2173 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2174 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2175 > examples/uImage.TQM850L 2176 Image Name: 2.4.4 kernel for TQM850L 2177 Created: Wed Jul 19 02:34:59 2000 2178 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2179 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2180 Load Address: 0x00000000 2181 Entry Point: 0x00000000 2182 2183To verify the contents of the image (or check for corruption): 2184 2185 -> tools/mkimage -l examples/uImage.TQM850L 2186 Image Name: 2.4.4 kernel for TQM850L 2187 Created: Wed Jul 19 02:34:59 2000 2188 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2189 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2190 Load Address: 0x00000000 2191 Entry Point: 0x00000000 2192 2193NOTE: for embedded systems where boot time is critical you can trade 2194speed for memory and install an UNCOMPRESSED image instead: this 2195needs more space in Flash, but boots much faster since it does not 2196need to be uncompressed: 2197 2198 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2199 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2200 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2201 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2202 > examples/uImage.TQM850L-uncompressed 2203 Image Name: 2.4.4 kernel for TQM850L 2204 Created: Wed Jul 19 02:34:59 2000 2205 Image Type: PowerPC Linux Kernel Image (uncompressed) 2206 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2207 Load Address: 0x00000000 2208 Entry Point: 0x00000000 2209 2210 2211Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2212when your kernel is intended to use an initial ramdisk: 2213 2214 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2215 > -A ppc -O linux -T ramdisk -C gzip \ 2216 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2217 Image Name: Simple Ramdisk Image 2218 Created: Wed Jan 12 14:01:50 2000 2219 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2220 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2221 Load Address: 0x00000000 2222 Entry Point: 0x00000000 2223 2224 2225Installing a Linux Image: 2226------------------------- 2227 2228To downloading a U-Boot image over the serial (console) interface, 2229you must convert the image to S-Record format: 2230 2231 objcopy -I binary -O srec examples/image examples/image.srec 2232 2233The 'objcopy' does not understand the information in the U-Boot 2234image header, so the resulting S-Record file will be relative to 2235address 0x00000000. To load it to a given address, you need to 2236specify the target address as 'offset' parameter with the 'loads' 2237command. 2238 2239Example: install the image to address 0x40100000 (which on the 2240TQM8xxL is in the first Flash bank): 2241 2242 => erase 40100000 401FFFFF 2243 2244 .......... done 2245 Erased 8 sectors 2246 2247 => loads 40100000 2248 ## Ready for S-Record download ... 2249 ~>examples/image.srec 2250 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2251 ... 2252 15989 15990 15991 15992 2253 [file transfer complete] 2254 [connected] 2255 ## Start Addr = 0x00000000 2256 2257 2258You can check the success of the download using the 'iminfo' command; 2259this includes a checksum verification so you can be sure no data 2260corruption happened: 2261 2262 => imi 40100000 2263 2264 ## Checking Image at 40100000 ... 2265 Image Name: 2.2.13 for initrd on TQM850L 2266 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2267 Data Size: 335725 Bytes = 327 kB = 0 MB 2268 Load Address: 00000000 2269 Entry Point: 0000000c 2270 Verifying Checksum ... OK 2271 2272 2273 2274Boot Linux: 2275----------- 2276 2277The "bootm" command is used to boot an application that is stored in 2278memory (RAM or Flash). In case of a Linux kernel image, the contents 2279of the "bootargs" environment variable is passed to the kernel as 2280parameters. You can check and modify this variable using the 2281"printenv" and "setenv" commands: 2282 2283 2284 => printenv bootargs 2285 bootargs=root=/dev/ram 2286 2287 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2288 2289 => printenv bootargs 2290 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2291 2292 => bootm 40020000 2293 ## Booting Linux kernel at 40020000 ... 2294 Image Name: 2.2.13 for NFS on TQM850L 2295 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2296 Data Size: 381681 Bytes = 372 kB = 0 MB 2297 Load Address: 00000000 2298 Entry Point: 0000000c 2299 Verifying Checksum ... OK 2300 Uncompressing Kernel Image ... OK 2301 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 2302 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2303 time_init: decrementer frequency = 187500000/60 2304 Calibrating delay loop... 49.77 BogoMIPS 2305 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2306 ... 2307 2308If you want to boot a Linux kernel with initial ram disk, you pass 2309the memory addreses of both the kernel and the initrd image (PPBCOOT 2310format!) to the "bootm" command: 2311 2312 => imi 40100000 40200000 2313 2314 ## Checking Image at 40100000 ... 2315 Image Name: 2.2.13 for initrd on TQM850L 2316 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2317 Data Size: 335725 Bytes = 327 kB = 0 MB 2318 Load Address: 00000000 2319 Entry Point: 0000000c 2320 Verifying Checksum ... OK 2321 2322 ## Checking Image at 40200000 ... 2323 Image Name: Simple Ramdisk Image 2324 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2325 Data Size: 566530 Bytes = 553 kB = 0 MB 2326 Load Address: 00000000 2327 Entry Point: 00000000 2328 Verifying Checksum ... OK 2329 2330 => bootm 40100000 40200000 2331 ## Booting Linux kernel at 40100000 ... 2332 Image Name: 2.2.13 for initrd on TQM850L 2333 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2334 Data Size: 335725 Bytes = 327 kB = 0 MB 2335 Load Address: 00000000 2336 Entry Point: 0000000c 2337 Verifying Checksum ... OK 2338 Uncompressing Kernel Image ... OK 2339 ## Loading RAMDisk Image at 40200000 ... 2340 Image Name: Simple Ramdisk Image 2341 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2342 Data Size: 566530 Bytes = 553 kB = 0 MB 2343 Load Address: 00000000 2344 Entry Point: 00000000 2345 Verifying Checksum ... OK 2346 Loading Ramdisk ... OK 2347 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 2348 Boot arguments: root=/dev/ram 2349 time_init: decrementer frequency = 187500000/60 2350 Calibrating delay loop... 49.77 BogoMIPS 2351 ... 2352 RAMDISK: Compressed image found at block 0 2353 VFS: Mounted root (ext2 filesystem). 2354 2355 bash# 2356 2357More About U-Boot Image Types: 2358------------------------------ 2359 2360U-Boot supports the following image types: 2361 2362 "Standalone Programs" are directly runnable in the environment 2363 provided by U-Boot; it is expected that (if they behave 2364 well) you can continue to work in U-Boot after return from 2365 the Standalone Program. 2366 "OS Kernel Images" are usually images of some Embedded OS which 2367 will take over control completely. Usually these programs 2368 will install their own set of exception handlers, device 2369 drivers, set up the MMU, etc. - this means, that you cannot 2370 expect to re-enter U-Boot except by resetting the CPU. 2371 "RAMDisk Images" are more or less just data blocks, and their 2372 parameters (address, size) are passed to an OS kernel that is 2373 being started. 2374 "Multi-File Images" contain several images, typically an OS 2375 (Linux) kernel image and one or more data images like 2376 RAMDisks. This construct is useful for instance when you want 2377 to boot over the network using BOOTP etc., where the boot 2378 server provides just a single image file, but you want to get 2379 for instance an OS kernel and a RAMDisk image. 2380 2381 "Multi-File Images" start with a list of image sizes, each 2382 image size (in bytes) specified by an "uint32_t" in network 2383 byte order. This list is terminated by an "(uint32_t)0". 2384 Immediately after the terminating 0 follow the images, one by 2385 one, all aligned on "uint32_t" boundaries (size rounded up to 2386 a multiple of 4 bytes). 2387 2388 "Firmware Images" are binary images containing firmware (like 2389 U-Boot or FPGA images) which usually will be programmed to 2390 flash memory. 2391 2392 "Script files" are command sequences that will be executed by 2393 U-Boot's command interpreter; this feature is especially 2394 useful when you configure U-Boot to use a real shell (hush) 2395 as command interpreter. 2396 2397 2398Standalone HOWTO: 2399================= 2400 2401One of the features of U-Boot is that you can dynamically load and 2402run "standalone" applications, which can use some resources of 2403U-Boot like console I/O functions or interrupt services. 2404 2405Two simple examples are included with the sources: 2406 2407"Hello World" Demo: 2408------------------- 2409 2410'examples/hello_world.c' contains a small "Hello World" Demo 2411application; it is automatically compiled when you build U-Boot. 2412It's configured to run at address 0x00040004, so you can play with it 2413like that: 2414 2415 => loads 2416 ## Ready for S-Record download ... 2417 ~>examples/hello_world.srec 2418 1 2 3 4 5 6 7 8 9 10 11 ... 2419 [file transfer complete] 2420 [connected] 2421 ## Start Addr = 0x00040004 2422 2423 => go 40004 Hello World! This is a test. 2424 ## Starting application at 0x00040004 ... 2425 Hello World 2426 argc = 7 2427 argv[0] = "40004" 2428 argv[1] = "Hello" 2429 argv[2] = "World!" 2430 argv[3] = "This" 2431 argv[4] = "is" 2432 argv[5] = "a" 2433 argv[6] = "test." 2434 argv[7] = "<NULL>" 2435 Hit any key to exit ... 2436 2437 ## Application terminated, rc = 0x0 2438 2439Another example, which demonstrates how to register a CPM interrupt 2440handler with the U-Boot code, can be found in 'examples/timer.c'. 2441Here, a CPM timer is set up to generate an interrupt every second. 2442The interrupt service routine is trivial, just printing a '.' 2443character, but this is just a demo program. The application can be 2444controlled by the following keys: 2445 2446 ? - print current values og the CPM Timer registers 2447 b - enable interrupts and start timer 2448 e - stop timer and disable interrupts 2449 q - quit application 2450 2451 => loads 2452 ## Ready for S-Record download ... 2453 ~>examples/timer.srec 2454 1 2 3 4 5 6 7 8 9 10 11 ... 2455 [file transfer complete] 2456 [connected] 2457 ## Start Addr = 0x00040004 2458 2459 => go 40004 2460 ## Starting application at 0x00040004 ... 2461 TIMERS=0xfff00980 2462 Using timer 1 2463 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2464 2465Hit 'b': 2466 [q, b, e, ?] Set interval 1000000 us 2467 Enabling timer 2468Hit '?': 2469 [q, b, e, ?] ........ 2470 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2471Hit '?': 2472 [q, b, e, ?] . 2473 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2474Hit '?': 2475 [q, b, e, ?] . 2476 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2477Hit '?': 2478 [q, b, e, ?] . 2479 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2480Hit 'e': 2481 [q, b, e, ?] ...Stopping timer 2482Hit 'q': 2483 [q, b, e, ?] ## Application terminated, rc = 0x0 2484 2485 2486NetBSD Notes: 2487============= 2488 2489Starting at version 0.9.2, U-Boot supports NetBSD both as host 2490(build U-Boot) and target system (boots NetBSD/mpc8xx). 2491 2492Building requires a cross environment; it is known to work on 2493NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2494need gmake since the Makefiles are not compatible with BSD make). 2495Note that the cross-powerpc package does not install include files; 2496attempting to build U-Boot will fail because <machine/ansi.h> is 2497missing. This file has to be installed and patched manually: 2498 2499 # cd /usr/pkg/cross/powerpc-netbsd/include 2500 # mkdir powerpc 2501 # ln -s powerpc machine 2502 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2503 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2504 2505Native builds *don't* work due to incompatibilities between native 2506and U-Boot include files. 2507 2508Booting assumes that (the first part of) the image booted is a 2509stage-2 loader which in turn loads and then invokes the kernel 2510proper. Loader sources will eventually appear in the NetBSD source 2511tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2512meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2513details. 2514 2515 2516Implementation Internals: 2517========================= 2518 2519The following is not intended to be a complete description of every 2520implementation detail. However, it should help to understand the 2521inner workings of U-Boot and make it easier to port it to custom 2522hardware. 2523 2524 2525Initial Stack, Global Data: 2526--------------------------- 2527 2528The implementation of U-Boot is complicated by the fact that U-Boot 2529starts running out of ROM (flash memory), usually without access to 2530system RAM (because the memory controller is not initialized yet). 2531This means that we don't have writable Data or BSS segments, and BSS 2532is not initialized as zero. To be able to get a C environment working 2533at all, we have to allocate at least a minimal stack. Implementation 2534options for this are defined and restricted by the CPU used: Some CPU 2535models provide on-chip memory (like the IMMR area on MPC8xx and 2536MPC826x processors), on others (parts of) the data cache can be 2537locked as (mis-) used as memory, etc. 2538 2539It is essential to remember this, since it has some impact on the C 2540code for the initialization procedures: 2541 2542* Initialized global data (data segment) is read-only. Do not attempt 2543 to write it. 2544 2545* Do not use any unitialized global data (or implicitely initialized 2546 as zero data - BSS segment) at all - this is undefined, initiali- 2547 zation is performed later (when relocationg to RAM). 2548 2549* Stack space is very limited. Avoid big data buffers or things like 2550 that. 2551 2552Having only the stack as writable memory limits means we cannot use 2553normal global data to share information beween the code. But it 2554turned out that the implementation of U-Boot can be greatly 2555simplified by making a global data structure (gd_t) available to all 2556functions. We could pass a pointer to this data as argument to _all_ 2557functions, but this would bloat the code. Instead we use a feature of 2558the GCC compiler (Global Register Variables) to share the data: we 2559place a pointer (gd) to the global data into a register which we 2560reserve for this purpose. 2561 2562When chosing a register for such a purpose we are restricted by the 2563relevant (E)ABI specifications for the current architecture, and by 2564GCC's implementation. 2565 2566For PowerPC, the following registers have specific use: 2567 R1: stack pointer 2568 R2: TOC pointer 2569 R3-R4: parameter passing and return values 2570 R5-R10: parameter passing 2571 R13: small data area pointer 2572 R30: GOT pointer 2573 R31: frame pointer 2574 2575 (U-Boot also uses R14 as internal GOT pointer.) 2576 2577 ==> U-Boot will use R29 to hold a pointer to the global data 2578 2579 Note: on PPC, we could use a static initializer (since the 2580 address of the global data structure is known at compile time), 2581 but it turned out that reserving a register results in somewhat 2582 smaller code - although the code savings are not that big (on 2583 average for all boards 752 bytes for the whole U-Boot image, 2584 624 text + 127 data). 2585 2586On ARM, the following registers are used: 2587 2588 R0: function argument word/integer result 2589 R1-R3: function argument word 2590 R9: GOT pointer 2591 R10: stack limit (used only if stack checking if enabled) 2592 R11: argument (frame) pointer 2593 R12: temporary workspace 2594 R13: stack pointer 2595 R14: link register 2596 R15: program counter 2597 2598 ==> U-Boot will use R8 to hold a pointer to the global data 2599 2600 2601 2602Memory Management: 2603------------------ 2604 2605U-Boot runs in system state and uses physical addresses, i.e. the 2606MMU is not used either for address mapping nor for memory protection. 2607 2608The available memory is mapped to fixed addresses using the memory 2609controller. In this process, a contiguous block is formed for each 2610memory type (Flash, SDRAM, SRAM), even when it consists of several 2611physical memory banks. 2612 2613U-Boot is installed in the first 128 kB of the first Flash bank (on 2614TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2615booting and sizing and initializing DRAM, the code relocates itself 2616to the upper end of DRAM. Immediately below the U-Boot code some 2617memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2618configuration setting]. Below that, a structure with global Board 2619Info data is placed, followed by the stack (growing downward). 2620 2621Additionally, some exception handler code is copied to the low 8 kB 2622of DRAM (0x00000000 ... 0x00001FFF). 2623 2624So a typical memory configuration with 16 MB of DRAM could look like 2625this: 2626 2627 0x0000 0000 Exception Vector code 2628 : 2629 0x0000 1FFF 2630 0x0000 2000 Free for Application Use 2631 : 2632 : 2633 2634 : 2635 : 2636 0x00FB FF20 Monitor Stack (Growing downward) 2637 0x00FB FFAC Board Info Data and permanent copy of global data 2638 0x00FC 0000 Malloc Arena 2639 : 2640 0x00FD FFFF 2641 0x00FE 0000 RAM Copy of Monitor Code 2642 ... eventually: LCD or video framebuffer 2643 ... eventually: pRAM (Protected RAM - unchanged by reset) 2644 0x00FF FFFF [End of RAM] 2645 2646 2647System Initialization: 2648---------------------- 2649 2650In the reset configuration, U-Boot starts at the reset entry point 2651(on most PowerPC systens at address 0x00000100). Because of the reset 2652configuration for CS0# this is a mirror of the onboard Flash memory. 2653To be able to re-map memory U-Boot then jumps to it's link address. 2654To be able to implement the initialization code in C, a (small!) 2655initial stack is set up in the internal Dual Ported RAM (in case CPUs 2656which provide such a feature like MPC8xx or MPC8260), or in a locked 2657part of the data cache. After that, U-Boot initializes the CPU core, 2658the caches and the SIU. 2659 2660Next, all (potentially) available memory banks are mapped using a 2661preliminary mapping. For example, we put them on 512 MB boundaries 2662(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2663on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2664programmed for SDRAM access. Using the temporary configuration, a 2665simple memory test is run that determines the size of the SDRAM 2666banks. 2667 2668When there is more than one SDRAM bank, and the banks are of 2669different size, the larger is mapped first. For equal size, the first 2670bank (CS2#) is mapped first. The first mapping is always for address 26710x00000000, with any additional banks following immediately to create 2672contiguous memory starting from 0. 2673 2674Then, the monitor installs itself at the upper end of the SDRAM area 2675and allocates memory for use by malloc() and for the global Board 2676Info data; also, the exception vector code is copied to the low RAM 2677pages, and the final stack is set up. 2678 2679Only after this relocation will you have a "normal" C environment; 2680until that you are restricted in several ways, mostly because you are 2681running from ROM, and because the code will have to be relocated to a 2682new address in RAM. 2683 2684 2685U-Boot Porting Guide: 2686---------------------- 2687 2688[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2689list, October 2002] 2690 2691 2692int main (int argc, char *argv[]) 2693{ 2694 sighandler_t no_more_time; 2695 2696 signal (SIGALRM, no_more_time); 2697 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2698 2699 if (available_money > available_manpower) { 2700 pay consultant to port U-Boot; 2701 return 0; 2702 } 2703 2704 Download latest U-Boot source; 2705 2706 Subscribe to u-boot-users mailing list; 2707 2708 if (clueless) { 2709 email ("Hi, I am new to U-Boot, how do I get started?"); 2710 } 2711 2712 while (learning) { 2713 Read the README file in the top level directory; 2714 Read http://www.denx.de/re/DPLG.html 2715 Read the source, Luke; 2716 } 2717 2718 if (available_money > toLocalCurrency ($2500)) { 2719 Buy a BDI2000; 2720 } else { 2721 Add a lot of aggravation and time; 2722 } 2723 2724 Create your own board support subdirectory; 2725 2726 Create your own board config file; 2727 2728 while (!running) { 2729 do { 2730 Add / modify source code; 2731 } until (compiles); 2732 Debug; 2733 if (clueless) 2734 email ("Hi, I am having problems..."); 2735 } 2736 Send patch file to Wolfgang; 2737 2738 return 0; 2739} 2740 2741void no_more_time (int sig) 2742{ 2743 hire_a_guru(); 2744} 2745 2746 2747 2748Coding Standards: 2749----------------- 2750 2751All contributions to U-Boot should conform to the Linux kernel 2752coding style; see the file "Documentation/CodingStyle" in your Linux 2753kernel source directory. 2754 2755Please note that U-Boot is implemented in C (and to some small parts 2756in Assembler); no C++ is used, so please do not use C++ style 2757comments (//) in your code. 2758 2759Submissions which do not conform to the standards may be returned 2760with a request to reformat the changes. 2761 2762 2763Submitting Patches: 2764------------------- 2765 2766Since the number of patches for U-Boot is growing, we need to 2767establish some rules. Submissions which do not conform to these rules 2768may be rejected, even when they contain important and valuable stuff. 2769 2770 2771When you send a patch, please include the following information with 2772it: 2773 2774* For bug fixes: a description of the bug and how your patch fixes 2775 this bug. Please try to include a way of demonstrating that the 2776 patch actually fixes something. 2777 2778* For new features: a description of the feature and your 2779 implementation. 2780 2781* A CHANGELOG entry as plaintext (separate from the patch) 2782 2783* For major contributions, your entry to the CREDITS file 2784 2785* When you add support for a new board, don't forget to add this 2786 board to the MAKEALL script, too. 2787 2788* If your patch adds new configuration options, don't forget to 2789 document these in the README file. 2790 2791* The patch itself. If you are accessing the CVS repository use "cvs 2792 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2793 version of diff does not support these options, then get the latest 2794 version of GNU diff. 2795 2796 We accept patches as plain text, MIME attachments or as uuencoded 2797 gzipped text. 2798 2799Notes: 2800 2801* Before sending the patch, run the MAKEALL script on your patched 2802 source tree and make sure that no errors or warnings are reported 2803 for any of the boards. 2804 2805* Keep your modifications to the necessary minimum: A patch 2806 containing several unrelated changes or arbitrary reformats will be 2807 returned with a request to re-formatting / split it. 2808 2809* If you modify existing code, make sure that your new code does not 2810 add to the memory footprint of the code ;-) Small is beautiful! 2811 When adding new features, these should compile conditionally only 2812 (using #ifdef), and the resulting code with the new feature 2813 disabled must not need more memory than the old code without your 2814 modification. 2815