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 341 342 ARM based boards: 343 ----------------- 344 345 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 346 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 347 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 348 CONFIG_TRAB 349 350 351- CPU Module Type: (if CONFIG_COGENT is defined) 352 Define exactly one of 353 CONFIG_CMA286_60_OLD 354--- FIXME --- not tested yet: 355 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 356 CONFIG_CMA287_23, CONFIG_CMA287_50 357 358- Motherboard Type: (if CONFIG_COGENT is defined) 359 Define exactly one of 360 CONFIG_CMA101, CONFIG_CMA102 361 362- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 363 Define one or more of 364 CONFIG_CMA302 365 366- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 367 Define one or more of 368 CONFIG_LCD_HEARTBEAT - update a character position on 369 the lcd display every second with 370 a "rotator" |\-/|\-/ 371 372- MPC824X Family Member (if CONFIG_MPC824X is defined) 373 Define exactly one of 374 CONFIG_MPC8240, CONFIG_MPC8245 375 376- 8xx CPU Options: (if using an 8xx cpu) 377 Define one or more of 378 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 379 no 32KHz reference PIT/RTC clock 380 381- Clock Interface: 382 CONFIG_CLOCKS_IN_MHZ 383 384 U-Boot stores all clock information in Hz 385 internally. For binary compatibility with older Linux 386 kernels (which expect the clocks passed in the 387 bd_info data to be in MHz) the environment variable 388 "clocks_in_mhz" can be defined so that U-Boot 389 converts clock data to MHZ before passing it to the 390 Linux kernel. 391 392 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 393 "clocks_in_mhz=1" is automatically included in the 394 default environment. 395 396- Console Interface: 397 Depending on board, define exactly one serial port 398 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 399 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 400 console by defining CONFIG_8xx_CONS_NONE 401 402 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 403 port routines must be defined elsewhere 404 (i.e. serial_init(), serial_getc(), ...) 405 406 CONFIG_CFB_CONSOLE 407 Enables console device for a color framebuffer. Needs following 408 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 409 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 410 (default big endian) 411 VIDEO_HW_RECTFILL graphic chip supports 412 rectangle fill 413 (cf. smiLynxEM) 414 VIDEO_HW_BITBLT graphic chip supports 415 bit-blit (cf. smiLynxEM) 416 VIDEO_VISIBLE_COLS visible pixel columns 417 (cols=pitch) 418 VIDEO_VISIBLE_ROWS visible pixel rows 419 VIDEO_PIXEL_SIZE bytes per pixel 420 VIDEO_DATA_FORMAT graphic data format 421 (0-5, cf. cfb_console.c) 422 VIDEO_FB_ADRS framebuffer address 423 VIDEO_KBD_INIT_FCT keyboard int fct 424 (i.e. i8042_kbd_init()) 425 VIDEO_TSTC_FCT test char fct 426 (i.e. i8042_tstc) 427 VIDEO_GETC_FCT get char fct 428 (i.e. i8042_getc) 429 CONFIG_CONSOLE_CURSOR cursor drawing on/off 430 (requires blink timer 431 cf. i8042.c) 432 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 433 CONFIG_CONSOLE_TIME display time/date info in 434 upper right corner 435 (requires CFG_CMD_DATE) 436 CONFIG_VIDEO_LOGO display Linux logo in 437 upper left corner 438 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 439 linux_logo.h for logo. 440 Requires CONFIG_VIDEO_LOGO 441 CONFIG_CONSOLE_EXTRA_INFO 442 addional board info beside 443 the logo 444 445 When CONFIG_CFB_CONSOLE is defined, video console is 446 default i/o. Serial console can be forced with 447 environment 'console=serial'. 448 449- Console Baudrate: 450 CONFIG_BAUDRATE - in bps 451 Select one of the baudrates listed in 452 CFG_BAUDRATE_TABLE, see below. 453 454- Interrupt driven serial port input: 455 CONFIG_SERIAL_SOFTWARE_FIFO 456 457 PPC405GP only. 458 Use an interrupt handler for receiving data on the 459 serial port. It also enables using hardware handshake 460 (RTS/CTS) and UART's built-in FIFO. Set the number of 461 bytes the interrupt driven input buffer should have. 462 463 Set to 0 to disable this feature (this is the default). 464 This will also disable hardware handshake. 465 466- Boot Delay: CONFIG_BOOTDELAY - in seconds 467 Delay before automatically booting the default image; 468 set to -1 to disable autoboot. 469 470 See doc/README.autoboot for these options that 471 work with CONFIG_BOOTDELAY. None are required. 472 CONFIG_BOOT_RETRY_TIME 473 CONFIG_BOOT_RETRY_MIN 474 CONFIG_AUTOBOOT_KEYED 475 CONFIG_AUTOBOOT_PROMPT 476 CONFIG_AUTOBOOT_DELAY_STR 477 CONFIG_AUTOBOOT_STOP_STR 478 CONFIG_AUTOBOOT_DELAY_STR2 479 CONFIG_AUTOBOOT_STOP_STR2 480 CONFIG_ZERO_BOOTDELAY_CHECK 481 CONFIG_RESET_TO_RETRY 482 483- Autoboot Command: 484 CONFIG_BOOTCOMMAND 485 Only needed when CONFIG_BOOTDELAY is enabled; 486 define a command string that is automatically executed 487 when no character is read on the console interface 488 within "Boot Delay" after reset. 489 490 CONFIG_BOOTARGS 491 This can be used to pass arguments to the bootm 492 command. The value of CONFIG_BOOTARGS goes into the 493 environment value "bootargs". 494 495 CONFIG_RAMBOOT and CONFIG_NFSBOOT 496 The value of these goes into the environment as 497 "ramboot" and "nfsboot" respectively, and can be used 498 as a convenience, when switching between booting from 499 ram and nfs. 500 501- Pre-Boot Commands: 502 CONFIG_PREBOOT 503 504 When this option is #defined, the existence of the 505 environment variable "preboot" will be checked 506 immediately before starting the CONFIG_BOOTDELAY 507 countdown and/or running the auto-boot command resp. 508 entering interactive mode. 509 510 This feature is especially useful when "preboot" is 511 automatically generated or modified. For an example 512 see the LWMON board specific code: here "preboot" is 513 modified when the user holds down a certain 514 combination of keys on the (special) keyboard when 515 booting the systems 516 517- Serial Download Echo Mode: 518 CONFIG_LOADS_ECHO 519 If defined to 1, all characters received during a 520 serial download (using the "loads" command) are 521 echoed back. This might be needed by some terminal 522 emulations (like "cu"), but may as well just take 523 time on others. This setting #define's the initial 524 value of the "loads_echo" environment variable. 525 526- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 527 CONFIG_KGDB_BAUDRATE 528 Select one of the baudrates listed in 529 CFG_BAUDRATE_TABLE, see below. 530 531- Monitor Functions: 532 CONFIG_COMMANDS 533 Most monitor functions can be selected (or 534 de-selected) by adjusting the definition of 535 CONFIG_COMMANDS; to select individual functions, 536 #define CONFIG_COMMANDS by "OR"ing any of the 537 following values: 538 539 #define enables commands: 540 ------------------------- 541 CFG_CMD_ASKENV * ask for env variable 542 CFG_CMD_BDI bdinfo 543 CFG_CMD_BEDBUG Include BedBug Debugger 544 CFG_CMD_BOOTD bootd 545 CFG_CMD_CACHE icache, dcache 546 CFG_CMD_CONSOLE coninfo 547 CFG_CMD_DATE * support for RTC, date/time... 548 CFG_CMD_DHCP DHCP support 549 CFG_CMD_ECHO * echo arguments 550 CFG_CMD_EEPROM * EEPROM read/write support 551 CFG_CMD_ELF bootelf, bootvx 552 CFG_CMD_ENV saveenv 553 CFG_CMD_FDC * Floppy Disk Support 554 CFG_CMD_FDOS * Dos diskette Support 555 CFG_CMD_FLASH flinfo, erase, protect 556 CFG_CMD_FPGA FPGA device initialization support 557 CFG_CMD_I2C * I2C serial bus support 558 CFG_CMD_IDE * IDE harddisk support 559 CFG_CMD_IMI iminfo 560 CFG_CMD_IMMAP * IMMR dump support 561 CFG_CMD_IRQ * irqinfo 562 CFG_CMD_KGDB * kgdb 563 CFG_CMD_LOADB loadb 564 CFG_CMD_LOADS loads 565 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 566 loop, mtest 567 CFG_CMD_MII MII utility commands 568 CFG_CMD_NET bootp, tftpboot, rarpboot 569 CFG_CMD_PCI * pciinfo 570 CFG_CMD_PCMCIA * PCMCIA support 571 CFG_CMD_REGINFO * Register dump 572 CFG_CMD_RUN run command in env variable 573 CFG_CMD_SCSI * SCSI Support 574 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 575 CFG_CMD_SPI * SPI serial bus support 576 CFG_CMD_USB * USB support 577 CFG_CMD_BSP * Board SPecific functions 578 ----------------------------------------------- 579 CFG_CMD_ALL all 580 581 CFG_CMD_DFL Default configuration; at the moment 582 this is includes all commands, except 583 the ones marked with "*" in the list 584 above. 585 586 If you don't define CONFIG_COMMANDS it defaults to 587 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 588 override the default settings in the respective 589 include file. 590 591 EXAMPLE: If you want all functions except of network 592 support you can write: 593 594 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 595 596 597 Note: Don't enable the "icache" and "dcache" commands 598 (configuration option CFG_CMD_CACHE) unless you know 599 what you (and your U-Boot users) are doing. Data 600 cache cannot be enabled on systems like the 8xx or 601 8260 (where accesses to the IMMR region must be 602 uncached), and it cannot be disabled on all other 603 systems where we (mis-) use the data cache to hold an 604 initial stack and some data. 605 606 607 XXX - this list needs to get updated! 608 609- Watchdog: 610 CONFIG_WATCHDOG 611 If this variable is defined, it enables watchdog 612 support. There must support in the platform specific 613 code for a watchdog. For the 8xx and 8260 CPUs, the 614 SIU Watchdog feature is enabled in the SYPCR 615 register. 616 617- Real-Time Clock: 618 619 When CFG_CMD_DATE is selected, the type of the RTC 620 has to be selected, too. Define exactly one of the 621 following options: 622 623 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 624 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 625 CONFIG_RTC_MC146818 - use MC146818 RTC 626 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 627 628- Timestamp Support: 629 630 When CONFIG_TIMESTAMP is selected, the timestamp 631 (date and time) of an image is printed by image 632 commands like bootm or iminfo. This option is 633 automatically enabled when you select CFG_CMD_DATE . 634 635- Partition Support: 636 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 637 and/or CONFIG_ISO_PARTITION 638 639 If IDE or SCSI support is enabled (CFG_CMD_IDE or 640 CFG_CMD_SCSI) you must configure support for at least 641 one partition type as well. 642 643- IDE Reset method: 644 CONFIG_IDE_RESET_ROUTINE 645 646 Set this to define that instead of a reset Pin, the 647 routine ide_set_reset(int idereset) will be used. 648 649- ATAPI Support: 650 CONFIG_ATAPI 651 652 Set this to enable ATAPI support. 653 654- SCSI Support: 655 At the moment only there is only support for the 656 SYM53C8XX SCSI controller; define 657 CONFIG_SCSI_SYM53C8XX to enable it. 658 659 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 660 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 661 CFG_SCSI_MAX_LUN] can be adjusted to define the 662 maximum numbers of LUNs, SCSI ID's and target 663 devices. 664 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 665 666- NETWORK Support (PCI): 667 CONFIG_EEPRO100 668 Support for Intel 82557/82559/82559ER chips. 669 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 670 write routine for first time initialisation. 671 672 CONFIG_TULIP 673 Support for Digital 2114x chips. 674 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 675 modem chip initialisation (KS8761/QS6611). 676 677 CONFIG_NATSEMI 678 Support for National dp83815 chips. 679 680 CONFIG_NS8382X 681 Support for National dp8382[01] gigabit chips. 682 683- USB Support: 684 At the moment only the UHCI host controller is 685 supported (PIP405, MIP405); define 686 CONFIG_USB_UHCI to enable it. 687 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 688 end define CONFIG_USB_STORAGE to enable the USB 689 storage devices. 690 Note: 691 Supported are USB Keyboards and USB Floppy drives 692 (TEAC FD-05PUB). 693 694- Keyboard Support: 695 CONFIG_ISA_KEYBOARD 696 697 Define this to enable standard (PC-Style) keyboard 698 support 699 700 CONFIG_I8042_KBD 701 Standard PC keyboard driver with US (is default) and 702 GERMAN key layout (switch via environment 'keymap=de') support. 703 Export function i8042_kbd_init, i8042_tstc and i8042_getc 704 for cfb_console. Supports cursor blinking. 705 706- Video support: 707 CONFIG_VIDEO 708 709 Define this to enable video support (for output to 710 video). 711 712 CONFIG_VIDEO_CT69000 713 714 Enable Chips & Technologies 69000 Video chip 715 716 CONFIG_VIDEO_SMI_LYNXEM 717 Enable Silicon Motion SMI 712/710/810 Video chip 718 Videomode are selected via environment 'videomode' with 719 standard LiLo mode numbers. 720 Following modes are supported (* is default): 721 722 800x600 1024x768 1280x1024 723 256 (8bit) 303* 305 307 724 65536 (16bit) 314 317 31a 725 16,7 Mill (24bit) 315 318 31b 726 (i.e. setenv videomode 317; saveenv; reset;) 727 728 CONFIG_VIDEO_SED13806 729 Enable Epson SED13806 driver. This driver supports 8bpp 730 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 731 or CONFIG_VIDEO_SED13806_16BPP 732 733 734- LCD Support: CONFIG_LCD 735 736 Define this to enable LCD support (for output to LCD 737 display); also select one of the supported displays 738 by defining one of these: 739 740 CONFIG_NEC_NL6648AC33: 741 742 NEC NL6648AC33-18. Active, color, single scan. 743 744 CONFIG_NEC_NL6648BC20 745 746 NEC NL6648BC20-08. 6.5", 640x480. 747 Active, color, single scan. 748 749 CONFIG_SHARP_16x9 750 751 Sharp 320x240. Active, color, single scan. 752 It isn't 16x9, and I am not sure what it is. 753 754 CONFIG_SHARP_LQ64D341 755 756 Sharp LQ64D341 display, 640x480. 757 Active, color, single scan. 758 759 CONFIG_HLD1045 760 761 HLD1045 display, 640x480. 762 Active, color, single scan. 763 764 CONFIG_OPTREX_BW 765 766 Optrex CBL50840-2 NF-FW 99 22 M5 767 or 768 Hitachi LMG6912RPFC-00T 769 or 770 Hitachi SP14Q002 771 772 320x240. Black & white. 773 774 Normally display is black on white background; define 775 CFG_WHITE_ON_BLACK to get it inverted. 776 777- Ethernet address: 778 CONFIG_ETHADDR 779 CONFIG_ETH2ADDR 780 CONFIG_ETH3ADDR 781 782 Define a default value for ethernet address to use 783 for the respective ethernet interface, in case this 784 is not determined automatically. 785 786- IP address: 787 CONFIG_IPADDR 788 789 Define a default value for the IP address to use for 790 the default ethernet interface, in case this is not 791 determined through e.g. bootp. 792 793- Server IP address: 794 CONFIG_SERVERIP 795 796 Defines a default value for theIP address of a TFTP 797 server to contact when using the "tftboot" command. 798 799- BOOTP Recovery Mode: 800 CONFIG_BOOTP_RANDOM_DELAY 801 802 If you have many targets in a network that try to 803 boot using BOOTP, you may want to avoid that all 804 systems send out BOOTP requests at precisely the same 805 moment (which would happen for instance at recovery 806 from a power failure, when all systems will try to 807 boot, thus flooding the BOOTP server. Defining 808 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 809 inserted before sending out BOOTP requests. The 810 following delays are insterted then: 811 812 1st BOOTP request: delay 0 ... 1 sec 813 2nd BOOTP request: delay 0 ... 2 sec 814 3rd BOOTP request: delay 0 ... 4 sec 815 4th and following 816 BOOTP requests: delay 0 ... 8 sec 817 818- Status LED: CONFIG_STATUS_LED 819 820 Several configurations allow to display the current 821 status using a LED. For instance, the LED will blink 822 fast while running U-Boot code, stop blinking as 823 soon as a reply to a BOOTP request was received, and 824 start blinking slow once the Linux kernel is running 825 (supported by a status LED driver in the Linux 826 kernel). Defining CONFIG_STATUS_LED enables this 827 feature in U-Boot. 828 829- CAN Support: CONFIG_CAN_DRIVER 830 831 Defining CONFIG_CAN_DRIVER enables CAN driver support 832 on those systems that support this (optional) 833 feature, like the TQM8xxL modules. 834 835- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 836 837 Enables I2C serial bus commands. If this is selected, 838 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 839 to include the appropriate I2C driver. 840 841 See also: common/cmd_i2c.c for a description of the 842 command line interface. 843 844 845 CONFIG_HARD_I2C 846 847 Selects the CPM hardware driver for I2C. 848 849 CONFIG_SOFT_I2C 850 851 Use software (aka bit-banging) driver instead of CPM 852 or similar hardware support for I2C. This is configured 853 via the following defines. 854 855 I2C_INIT 856 857 (Optional). Any commands necessary to enable I2C 858 controller or configure ports. 859 860 I2C_PORT 861 862 (Only for MPC8260 CPU). The I/O port to use (the code 863 assumes both bits are on the same port). Valid values 864 are 0..3 for ports A..D. 865 866 I2C_ACTIVE 867 868 The code necessary to make the I2C data line active 869 (driven). If the data line is open collector, this 870 define can be null. 871 872 I2C_TRISTATE 873 874 The code necessary to make the I2C data line tri-stated 875 (inactive). If the data line is open collector, this 876 define can be null. 877 878 I2C_READ 879 880 Code that returns TRUE if the I2C data line is high, 881 FALSE if it is low. 882 883 I2C_SDA(bit) 884 885 If <bit> is TRUE, sets the I2C data line high. If it 886 is FALSE, it clears it (low). 887 888 I2C_SCL(bit) 889 890 If <bit> is TRUE, sets the I2C clock line high. If it 891 is FALSE, it clears it (low). 892 893 I2C_DELAY 894 895 This delay is invoked four times per clock cycle so this 896 controls the rate of data transfer. The data rate thus 897 is 1 / (I2C_DELAY * 4). 898 899- SPI Support: CONFIG_SPI 900 901 Enables SPI driver (so far only tested with 902 SPI EEPROM, also an instance works with Crystal A/D and 903 D/As on the SACSng board) 904 905 CONFIG_SPI_X 906 907 Enables extended (16-bit) SPI EEPROM addressing. 908 (symmetrical to CONFIG_I2C_X) 909 910 CONFIG_SOFT_SPI 911 912 Enables a software (bit-bang) SPI driver rather than 913 using hardware support. This is a general purpose 914 driver that only requires three general I/O port pins 915 (two outputs, one input) to function. If this is 916 defined, the board configuration must define several 917 SPI configuration items (port pins to use, etc). For 918 an example, see include/configs/sacsng.h. 919 920- FPGA Support: CONFIG_FPGA_COUNT 921 922 Specify the number of FPGA devices to support. 923 924 CONFIG_FPGA 925 926 Used to specify the types of FPGA devices. For 927 example, 928 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 929 930 CFG_FPGA_PROG_FEEDBACK 931 932 Enable printing of hash marks during FPGA 933 configuration. 934 935 CFG_FPGA_CHECK_BUSY 936 937 Enable checks on FPGA configuration interface busy 938 status by the configuration function. This option 939 will require a board or device specific function to 940 be written. 941 942 CONFIG_FPGA_DELAY 943 944 If defined, a function that provides delays in the 945 FPGA configuration driver. 946 947 CFG_FPGA_CHECK_CTRLC 948 949 Allow Control-C to interrupt FPGA configuration 950 951 CFG_FPGA_CHECK_ERROR 952 953 Check for configuration errors during FPGA bitfile 954 loading. For example, abort during Virtex II 955 configuration if the INIT_B line goes low (which 956 indicated a CRC error). 957 958 CFG_FPGA_WAIT_INIT 959 960 Maximum time to wait for the INIT_B line to deassert 961 after PROB_B has been deasserted during a Virtex II 962 FPGA configuration sequence. The default time is 500 mS. 963 964 CFG_FPGA_WAIT_BUSY 965 966 Maximum time to wait for BUSY to deassert during 967 Virtex II FPGA configuration. The default is 5 mS. 968 969 CFG_FPGA_WAIT_CONFIG 970 971 Time to wait after FPGA configuration. The default is 972 200 mS. 973 974- FPGA Support: CONFIG_FPGA_COUNT 975 976 Specify the number of FPGA devices to support. 977 978 CONFIG_FPGA 979 980 Used to specify the types of FPGA devices. For example, 981 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 982 983 CFG_FPGA_PROG_FEEDBACK 984 985 Enable printing of hash marks during FPGA configuration. 986 987 CFG_FPGA_CHECK_BUSY 988 989 Enable checks on FPGA configuration interface busy 990 status by the configuration function. This option 991 will require a board or device specific function to 992 be written. 993 994 CONFIG_FPGA_DELAY 995 996 If defined, a function that provides delays in the FPGA 997 configuration driver. 998 999 CFG_FPGA_CHECK_CTRLC 1000 Allow Control-C to interrupt FPGA configuration 1001 1002 CFG_FPGA_CHECK_ERROR 1003 1004 Check for configuration errors during FPGA bitfile 1005 loading. For example, abort during Virtex II 1006 configuration if the INIT_B line goes low (which 1007 indicated a CRC error). 1008 1009 CFG_FPGA_WAIT_INIT 1010 1011 Maximum time to wait for the INIT_B line to deassert 1012 after PROB_B has been deasserted during a Virtex II 1013 FPGA configuration sequence. The default time is 500 1014 mS. 1015 1016 CFG_FPGA_WAIT_BUSY 1017 1018 Maximum time to wait for BUSY to deassert during 1019 Virtex II FPGA configuration. The default is 5 mS. 1020 1021 CFG_FPGA_WAIT_CONFIG 1022 1023 Time to wait after FPGA configuration. The default is 1024 200 mS. 1025 1026- Configuration Management: 1027 CONFIG_IDENT_STRING 1028 1029 If defined, this string will be added to the U-Boot 1030 version information (U_BOOT_VERSION) 1031 1032- Vendor Parameter Protection: 1033 1034 U-Boot considers the values of the environment 1035 variables "serial#" (Board Serial Number) and 1036 "ethaddr" (Ethernet Address) to bb parameters that 1037 are set once by the board vendor / manufacturer, and 1038 protects these variables from casual modification by 1039 the user. Once set, these variables are read-only, 1040 and write or delete attempts are rejected. You can 1041 change this behviour: 1042 1043 If CONFIG_ENV_OVERWRITE is #defined in your config 1044 file, the write protection for vendor parameters is 1045 completely disabled. Anybody can change or delte 1046 these parameters. 1047 1048 Alternatively, if you #define _both_ CONFIG_ETHADDR 1049 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1050 ethernet address is installed in the environment, 1051 which can be changed exactly ONCE by the user. [The 1052 serial# is unaffected by this, i. e. it remains 1053 read-only.] 1054 1055- Protected RAM: 1056 CONFIG_PRAM 1057 1058 Define this variable to enable the reservation of 1059 "protected RAM", i. e. RAM which is not overwritten 1060 by U-Boot. Define CONFIG_PRAM to hold the number of 1061 kB you want to reserve for pRAM. You can overwrite 1062 this default value by defining an environment 1063 variable "pram" to the number of kB you want to 1064 reserve. Note that the board info structure will 1065 still show the full amount of RAM. If pRAM is 1066 reserved, a new environment variable "mem" will 1067 automatically be defined to hold the amount of 1068 remaining RAM in a form that can be passed as boot 1069 argument to Linux, for instance like that: 1070 1071 setenv bootargs ... mem=\$(mem) 1072 saveenv 1073 1074 This way you can tell Linux not to use this memory, 1075 either, which results in a memory region that will 1076 not be affected by reboots. 1077 1078 *WARNING* If your board configuration uses automatic 1079 detection of the RAM size, you must make sure that 1080 this memory test is non-destructive. So far, the 1081 following board configurations are known to be 1082 "pRAM-clean": 1083 1084 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1085 HERMES, IP860, RPXlite, LWMON, LANTEC, 1086 PCU_E, FLAGADM, TQM8260 1087 1088- Error Recovery: 1089 CONFIG_PANIC_HANG 1090 1091 Define this variable to stop the system in case of a 1092 fatal error, so that you have to reset it manually. 1093 This is probably NOT a good idea for an embedded 1094 system where you want to system to reboot 1095 automatically as fast as possible, but it may be 1096 useful during development since you can try to debug 1097 the conditions that lead to the situation. 1098 1099 CONFIG_NET_RETRY_COUNT 1100 1101 This variable defines the number of retries for 1102 network operations like ARP, RARP, TFTP, or BOOTP 1103 before giving up the operation. If not defined, a 1104 default value of 5 is used. 1105 1106- Command Interpreter: 1107 CFG_HUSH_PARSER 1108 1109 Define this variable to enable the "hush" shell (from 1110 Busybox) as command line interpreter, thus enabling 1111 powerful command line syntax like 1112 if...then...else...fi conditionals or `&&' and '||' 1113 constructs ("shell scripts"). 1114 1115 If undefined, you get the old, much simpler behaviour 1116 with a somewhat smaller memory footprint. 1117 1118 1119 CFG_PROMPT_HUSH_PS2 1120 1121 This defines the secondary prompt string, which is 1122 printed when the command interpreter needs more input 1123 to complete a command. Usually "> ". 1124 1125 Note: 1126 1127 In the current implementation, the local variables 1128 space and global environment variables space are 1129 separated. Local variables are those you define by 1130 simply typing like `name=value'. To access a local 1131 variable later on, you have write `$name' or 1132 `${name}'; variable directly by typing say `$name' at 1133 the command prompt. 1134 1135 Global environment variables are those you use 1136 setenv/printenv to work with. To run a command stored 1137 in such a variable, you need to use the run command, 1138 and you must not use the '$' sign to access them. 1139 1140 To store commands and special characters in a 1141 variable, please use double quotation marks 1142 surrounding the whole text of the variable, instead 1143 of the backslashes before semicolons and special 1144 symbols. 1145 1146- Default Environment 1147 CONFIG_EXTRA_ENV_SETTINGS 1148 1149 Define this to contain any number of null terminated 1150 strings (variable = value pairs) that will be part of 1151 the default enviroment compiled into the boot image. 1152 1153 For example, place something like this in your 1154 board's config file: 1155 1156 #define CONFIG_EXTRA_ENV_SETTINGS \ 1157 "myvar1=value1\0" \ 1158 "myvar2=value2\0" 1159 1160 Warning: This method is based on knowledge about the 1161 internal format how the environment is stored by the 1162 U-Boot code. This is NOT an official, exported 1163 interface! Although it is unlikely that this format 1164 will change soon, but there is no guarantee either. 1165 You better know what you are doing here. 1166 1167 Note: overly (ab)use of the default environment is 1168 discouraged. Make sure to check other ways to preset 1169 the environment like the autoscript function or the 1170 boot command first. 1171 1172- Show boot progress 1173 CONFIG_SHOW_BOOT_PROGRESS 1174 1175 Defining this option allows to add some board- 1176 specific code (calling a user-provided function 1177 "show_boot_progress(int)") that enables you to show 1178 the system's boot progress on some display (for 1179 example, some LED's) on your board. At the moment, 1180 the following checkpoints are implemented: 1181 1182 Arg Where When 1183 1 common/cmd_bootm.c before attempting to boot an image 1184 -1 common/cmd_bootm.c Image header has bad magic number 1185 2 common/cmd_bootm.c Image header has correct magic number 1186 -2 common/cmd_bootm.c Image header has bad checksum 1187 3 common/cmd_bootm.c Image header has correct checksum 1188 -3 common/cmd_bootm.c Image data has bad checksum 1189 4 common/cmd_bootm.c Image data has correct checksum 1190 -4 common/cmd_bootm.c Image is for unsupported architecture 1191 5 common/cmd_bootm.c Architecture check OK 1192 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1193 6 common/cmd_bootm.c Image Type check OK 1194 -6 common/cmd_bootm.c gunzip uncompression error 1195 -7 common/cmd_bootm.c Unimplemented compression type 1196 7 common/cmd_bootm.c Uncompression OK 1197 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1198 8 common/cmd_bootm.c Image Type check OK 1199 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1200 9 common/cmd_bootm.c Start initial ramdisk verification 1201 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1202 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1203 10 common/cmd_bootm.c Ramdisk header is OK 1204 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1205 11 common/cmd_bootm.c Ramdisk data has correct checksum 1206 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1207 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1208 13 common/cmd_bootm.c Start multifile image verification 1209 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1210 15 common/cmd_bootm.c All preparation done, transferring control to OS 1211 1212 -1 common/cmd_doc.c Bad usage of "doc" command 1213 -1 common/cmd_doc.c No boot device 1214 -1 common/cmd_doc.c Unknown Chip ID on boot device 1215 -1 common/cmd_doc.c Read Error on boot device 1216 -1 common/cmd_doc.c Image header has bad magic number 1217 1218 -1 common/cmd_ide.c Bad usage of "ide" command 1219 -1 common/cmd_ide.c No boot device 1220 -1 common/cmd_ide.c Unknown boot device 1221 -1 common/cmd_ide.c Unknown partition table 1222 -1 common/cmd_ide.c Invalid partition type 1223 -1 common/cmd_ide.c Read Error on boot device 1224 -1 common/cmd_ide.c Image header has bad magic number 1225 1226 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1227 1228 1229Modem Support: 1230-------------- 1231 1232[so far only for SMDK2400 board] 1233 1234- Modem support endable: 1235 CONFIG_MODEM_SUPPORT 1236 1237- RTS/CTS Flow control enable: 1238 CONFIG_HWFLOW 1239 1240- Modem debug support: 1241 CONFIG_MODEM_SUPPORT_DEBUG 1242 1243 Enables debugging stuff (char screen[1024], dbg()) 1244 for modem support. Useful only with BDI2000. 1245 1246- General: 1247 1248 In the target system modem support is enabled when a 1249 specific key (key combination) is pressed during 1250 power-on. Otherwise U-Boot will boot normally 1251 (autoboot). The key_pressed() fuction is called from 1252 board_init(). Currently key_pressed() is a dummy 1253 function, returning 1 and thus enabling modem 1254 initialization. 1255 1256 If there are no modem init strings in the 1257 environment, U-Boot proceed to autoboot; the 1258 previous output (banner, info printfs) will be 1259 supressed, though. 1260 1261 See also: doc/README.Modem 1262 1263 1264 1265 1266Configuration Settings: 1267----------------------- 1268 1269- CFG_LONGHELP: Defined when you want long help messages included; 1270 undefine this when you're short of memory. 1271 1272- CFG_PROMPT: This is what U-Boot prints on the console to 1273 prompt for user input. 1274 1275- CFG_CBSIZE: Buffer size for input from the Console 1276 1277- CFG_PBSIZE: Buffer size for Console output 1278 1279- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1280 1281- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1282 the application (usually a Linux kernel) when it is 1283 booted 1284 1285- CFG_BAUDRATE_TABLE: 1286 List of legal baudrate settings for this board. 1287 1288- CFG_CONSOLE_INFO_QUIET 1289 Suppress display of console information at boot. 1290 1291- CFG_CONSOLE_IS_IN_ENV 1292 If the board specific function 1293 extern int overwrite_console (void); 1294 returns 1, the stdin, stderr and stdout are switched to the 1295 serial port, else the settings in the environment are used. 1296 1297- CFG_CONSOLE_OVERWRITE_ROUTINE 1298 Enable the call to overwrite_console(). 1299 1300- CFG_CONSOLE_ENV_OVERWRITE 1301 Enable overwrite of previous console environment settings. 1302 1303- CFG_MEMTEST_START, CFG_MEMTEST_END: 1304 Begin and End addresses of the area used by the 1305 simple memory test. 1306 1307- CFG_ALT_MEMTEST: 1308 Enable an alternate, more extensive memory test. 1309 1310- CFG_TFTP_LOADADDR: 1311 Default load address for network file downloads 1312 1313- CFG_LOADS_BAUD_CHANGE: 1314 Enable temporary baudrate change while serial download 1315 1316- CFG_SDRAM_BASE: 1317 Physical start address of SDRAM. _Must_ be 0 here. 1318 1319- CFG_MBIO_BASE: 1320 Physical start address of Motherboard I/O (if using a 1321 Cogent motherboard) 1322 1323- CFG_FLASH_BASE: 1324 Physical start address of Flash memory. 1325 1326- CFG_MONITOR_BASE: 1327 Physical start address of boot monitor code (set by 1328 make config files to be same as the text base address 1329 (TEXT_BASE) used when linking) - same as 1330 CFG_FLASH_BASE when booting from flash. 1331 1332- CFG_MONITOR_LEN: 1333 Size of memory reserved for monitor code 1334 1335- CFG_MALLOC_LEN: 1336 Size of DRAM reserved for malloc() use. 1337 1338- CFG_BOOTMAPSZ: 1339 Maximum size of memory mapped by the startup code of 1340 the Linux kernel; all data that must be processed by 1341 the Linux kernel (bd_info, boot arguments, eventually 1342 initrd image) must be put below this limit. 1343 1344- CFG_MAX_FLASH_BANKS: 1345 Max number of Flash memory banks 1346 1347- CFG_MAX_FLASH_SECT: 1348 Max number of sectors on a Flash chip 1349 1350- CFG_FLASH_ERASE_TOUT: 1351 Timeout for Flash erase operations (in ms) 1352 1353- CFG_FLASH_WRITE_TOUT: 1354 Timeout for Flash write operations (in ms) 1355 1356- CFG_DIRECT_FLASH_TFTP: 1357 1358 Enable TFTP transfers directly to flash memory; 1359 without this option such a download has to be 1360 performed in two steps: (1) download to RAM, and (2) 1361 copy from RAM to flash. 1362 1363 The two-step approach is usually more reliable, since 1364 you can check if the download worked before you erase 1365 the flash, but in some situations (when sytem RAM is 1366 too limited to allow for a tempory copy of the 1367 downloaded image) this option may be very useful. 1368 1369- CFG_FLASH_CFI: 1370 Define if the flash driver uses extra elements in the 1371 common flash structure for storing flash geometry 1372 1373The following definitions that deal with the placement and management 1374of environment data (variable area); in general, we support the 1375following configurations: 1376 1377- CFG_ENV_IS_IN_FLASH: 1378 1379 Define this if the environment is in flash memory. 1380 1381 a) The environment occupies one whole flash sector, which is 1382 "embedded" in the text segment with the U-Boot code. This 1383 happens usually with "bottom boot sector" or "top boot 1384 sector" type flash chips, which have several smaller 1385 sectors at the start or the end. For instance, such a 1386 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1387 such a case you would place the environment in one of the 1388 4 kB sectors - with U-Boot code before and after it. With 1389 "top boot sector" type flash chips, you would put the 1390 environment in one of the last sectors, leaving a gap 1391 between U-Boot and the environment. 1392 1393 - CFG_ENV_OFFSET: 1394 1395 Offset of environment data (variable area) to the 1396 beginning of flash memory; for instance, with bottom boot 1397 type flash chips the second sector can be used: the offset 1398 for this sector is given here. 1399 1400 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1401 1402 - CFG_ENV_ADDR: 1403 1404 This is just another way to specify the start address of 1405 the flash sector containing the environment (instead of 1406 CFG_ENV_OFFSET). 1407 1408 - CFG_ENV_SECT_SIZE: 1409 1410 Size of the sector containing the environment. 1411 1412 1413 b) Sometimes flash chips have few, equal sized, BIG sectors. 1414 In such a case you don't want to spend a whole sector for 1415 the environment. 1416 1417 - CFG_ENV_SIZE: 1418 1419 If you use this in combination with CFG_ENV_IS_IN_FLASH 1420 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1421 of this flash sector for the environment. This saves 1422 memory for the RAM copy of the environment. 1423 1424 It may also save flash memory if you decide to use this 1425 when your environment is "embedded" within U-Boot code, 1426 since then the remainder of the flash sector could be used 1427 for U-Boot code. It should be pointed out that this is 1428 STRONGLY DISCOURAGED from a robustness point of view: 1429 updating the environment in flash makes it always 1430 necessary to erase the WHOLE sector. If something goes 1431 wrong before the contents has been restored from a copy in 1432 RAM, your target system will be dead. 1433 1434 - CFG_ENV_ADDR_REDUND 1435 CFG_ENV_SIZE_REDUND 1436 1437 These settings describe a second storage area used to hold 1438 a redundand copy of the environment data, so that there is 1439 a valid backup copy in case there is a power failur during 1440 a "saveenv" operation. 1441 1442BE CAREFUL! Any changes to the flash layout, and some changes to the 1443source code will make it necessary to adapt <board>/u-boot.lds* 1444accordingly! 1445 1446 1447- CFG_ENV_IS_IN_NVRAM: 1448 1449 Define this if you have some non-volatile memory device 1450 (NVRAM, battery buffered SRAM) which you want to use for the 1451 environment. 1452 1453 - CFG_ENV_ADDR: 1454 - CFG_ENV_SIZE: 1455 1456 These two #defines are used to determin the memory area you 1457 want to use for environment. It is assumed that this memory 1458 can just be read and written to, without any special 1459 provision. 1460 1461BE CAREFUL! The first access to the environment happens quite early 1462in U-Boot initalization (when we try to get the setting of for the 1463console baudrate). You *MUST* have mappend your NVRAM area then, or 1464U-Boot will hang. 1465 1466Please note that even with NVRAM we still use a copy of the 1467environment in RAM: we could work on NVRAM directly, but we want to 1468keep settings there always unmodified except somebody uses "saveenv" 1469to save the current settings. 1470 1471 1472- CFG_ENV_IS_IN_EEPROM: 1473 1474 Use this if you have an EEPROM or similar serial access 1475 device and a driver for it. 1476 1477 - CFG_ENV_OFFSET: 1478 - CFG_ENV_SIZE: 1479 1480 These two #defines specify the offset and size of the 1481 environment area within the total memory of your EEPROM. 1482 1483 - CFG_I2C_EEPROM_ADDR: 1484 If defined, specified the chip address of the EEPROM device. 1485 The default address is zero. 1486 1487 - CFG_EEPROM_PAGE_WRITE_BITS: 1488 If defined, the number of bits used to address bytes in a 1489 single page in the EEPROM device. A 64 byte page, for example 1490 would require six bits. 1491 1492 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1493 If defined, the number of milliseconds to delay between 1494 page writes. The default is zero milliseconds. 1495 1496 - CFG_I2C_EEPROM_ADDR_LEN: 1497 The length in bytes of the EEPROM memory array address. Note 1498 that this is NOT the chip address length! 1499 1500 - CFG_EEPROM_SIZE: 1501 The size in bytes of the EEPROM device. 1502 1503 - CFG_I2C_EEPROM_ADDR: 1504 If defined, specified the chip address of the EEPROM device. 1505 The default address is zero. 1506 1507 - CFG_EEPROM_PAGE_WRITE_BITS: 1508 If defined, the number of bits used to address bytes in a 1509 single page in the EEPROM device. A 64 byte page, for example 1510 would require six bits. 1511 1512 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1513 If defined, the number of milliseconds to delay between 1514 page writes. The default is zero milliseconds. 1515 1516 - CFG_I2C_EEPROM_ADDR_LEN: 1517 The length in bytes of the EEPROM memory array address. Note 1518 that this is NOT the chip address length! 1519 1520 - CFG_EEPROM_SIZE: 1521 The size in bytes of the EEPROM device. 1522 1523- CFG_SPI_INIT_OFFSET 1524 1525 Defines offset to the initial SPI buffer area in DPRAM. The 1526 area is used at an early stage (ROM part) if the environment 1527 is configured to reside in the SPI EEPROM: We need a 520 byte 1528 scratch DPRAM area. It is used between the two initialization 1529 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1530 to be a good choice since it makes it far enough from the 1531 start of the data area as well as from the stack pointer. 1532 1533Please note that the environment is read-only as long as the monitor 1534has been relocated to RAM and a RAM copy of the environment has been 1535created; also, when using EEPROM you will have to use getenv_r() 1536until then to read environment variables. 1537 1538The environment is now protected by a CRC32 checksum. Before the 1539monitor is relocated into RAM, as a result of a bad CRC you will be 1540working with the compiled-in default environment - *silently*!!! 1541[This is necessary, because the first environment variable we need is 1542the "baudrate" setting for the console - if we have a bad CRC, we 1543don't have any device yet where we could complain.] 1544 1545Note: once the monitor has been relocated, then it will complain if 1546the default environment is used; a new CRC is computed as soon as you 1547use the "setenv" command to modify / delete / add any environment 1548variable [even when you try to delete a non-existing variable!]. 1549 1550Note2: you must edit your u-boot.lds file to reflect this 1551configuration. 1552 1553 1554Low Level (hardware related) configuration options: 1555 1556- CFG_CACHELINE_SIZE: 1557 Cache Line Size of the CPU. 1558 1559- CFG_DEFAULT_IMMR: 1560 Default address of the IMMR after system reset. 1561 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1562 to be able to adjust the position of the IMMR 1563 register after a reset. 1564 1565- Floppy Disk Support: 1566 CFG_FDC_DRIVE_NUMBER 1567 1568 the default drive number (default value 0) 1569 1570 CFG_ISA_IO_STRIDE 1571 1572 defines the spacing between fdc chipset registers 1573 (default value 1) 1574 1575 CFG_ISA_IO_OFFSET 1576 1577 defines the offset of register from address. It 1578 depends on which part of the data bus is connected to 1579 the fdc chipset. (default value 0) 1580 1581 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1582 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1583 default value. 1584 1585 if CFG_FDC_HW_INIT is defined, then the function 1586 fdc_hw_init() is called at the beginning of the FDC 1587 setup. fdc_hw_init() must be provided by the board 1588 source code. It is used to make hardware dependant 1589 initializations. 1590 1591- CFG_IMMR: Physical address of the Internal Memory Mapped 1592 Register; DO NOT CHANGE! (11-4) 1593 [MPC8xx systems only] 1594 1595- CFG_INIT_RAM_ADDR: 1596 1597 Start address of memory area tha can be used for 1598 initial data and stack; please note that this must be 1599 writable memory that is working WITHOUT special 1600 initialization, i. e. you CANNOT use normal RAM which 1601 will become available only after programming the 1602 memory controller and running certain initialization 1603 sequences. 1604 1605 U-Boot uses the following memory types: 1606 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1607 - MPC824X: data cache 1608 - PPC4xx: data cache 1609 1610- CFG_INIT_DATA_OFFSET: 1611 1612 Offset of the initial data structure in the memory 1613 area defined by CFG_INIT_RAM_ADDR. Usually 1614 CFG_INIT_DATA_OFFSET is chosen such that the initial 1615 data is located at the end of the available space 1616 (sometimes written as (CFG_INIT_RAM_END - 1617 CFG_INIT_DATA_SIZE), and the initial stack is just 1618 below that area (growing from (CFG_INIT_RAM_ADDR + 1619 CFG_INIT_DATA_OFFSET) downward. 1620 1621 Note: 1622 On the MPC824X (or other systems that use the data 1623 cache for initial memory) the address chosen for 1624 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1625 point to an otherwise UNUSED address space between 1626 the top of RAM and the start of the PCI space. 1627 1628- CFG_SIUMCR: SIU Module Configuration (11-6) 1629 1630- CFG_SYPCR: System Protection Control (11-9) 1631 1632- CFG_TBSCR: Time Base Status and Control (11-26) 1633 1634- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1635 1636- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1637 1638- CFG_SCCR: System Clock and reset Control Register (15-27) 1639 1640- CFG_OR_TIMING_SDRAM: 1641 SDRAM timing 1642 1643- CFG_MAMR_PTA: 1644 periodic timer for refresh 1645 1646- CFG_DER: Debug Event Register (37-47) 1647 1648- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1649 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1650 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1651 CFG_BR1_PRELIM: 1652 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1653 1654- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1655 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1656 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1657 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1658 1659- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1660 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1661 Machine Mode Register and Memory Periodic Timer 1662 Prescaler definitions (SDRAM timing) 1663 1664- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1665 enable I2C microcode relocation patch (MPC8xx); 1666 define relocation offset in DPRAM [DSP2] 1667 1668- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1669 enable SPI microcode relocation patch (MPC8xx); 1670 define relocation offset in DPRAM [SCC4] 1671 1672- CFG_USE_OSCCLK: 1673 Use OSCM clock mode on MBX8xx board. Be careful, 1674 wrong setting might damage your board. Read 1675 doc/README.MBX before setting this variable! 1676 1677- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1678 Offset of the bootmode word in DPRAM used by post 1679 (Power On Self Tests). This definition overrides 1680 #define'd default value in commproc.h resp. 1681 cpm_8260.h. 1682 1683Building the Software: 1684====================== 1685 1686Building U-Boot has been tested in native PPC environments (on a 1687PowerBook G3 running LinuxPPC 2000) and in cross environments 1688(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1689NetBSD 1.5 on x86). 1690 1691If you are not using a native PPC environment, it is assumed that you 1692have the GNU cross compiling tools available in your path and named 1693with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1694you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1695the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1696change it to: 1697 1698 CROSS_COMPILE = ppc_4xx- 1699 1700 1701U-Boot is intended to be simple to build. After installing the 1702sources you must configure U-Boot for one specific board type. This 1703is done by typing: 1704 1705 make NAME_config 1706 1707where "NAME_config" is the name of one of the existing 1708configurations; the following names are supported: 1709 1710 ADCIOP_config GTH_config TQM850L_config 1711 ADS860_config IP860_config TQM855L_config 1712 AR405_config IVML24_config TQM860L_config 1713 CANBT_config IVMS8_config WALNUT405_config 1714 CPCI405_config LANTEC_config cogent_common_config 1715 CPCIISER4_config MBX_config cogent_mpc8260_config 1716 CU824_config MBX860T_config cogent_mpc8xx_config 1717 ESTEEM192E_config RPXlite_config hermes_config 1718 ETX094_config RPXsuper_config hymod_config 1719 FADS823_config SM850_config lwmon_config 1720 FADS850SAR_config SPD823TS_config pcu_e_config 1721 FADS860T_config SXNI855T_config rsdproto_config 1722 FPS850L_config Sandpoint8240_config sbc8260_config 1723 GENIETV_config TQM823L_config PIP405_config 1724 GEN860T_config EBONY_config FPS860L_config 1725 1726Note: for some board special configuration names may exist; check if 1727 additional information is available from the board vendor; for 1728 instance, the TQM8xxL systems run normally at 50 MHz and use a 1729 SCC for 10baseT ethernet; there are also systems with 80 MHz 1730 CPU clock, and an optional Fast Ethernet module is available 1731 for CPU's with FEC. You can select such additional "features" 1732 when chosing the configuration, i. e. 1733 1734 make TQM860L_config 1735 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1736 1737 make TQM860L_FEC_config 1738 - will configure for a TQM860L at 50MHz with FEC for ethernet 1739 1740 make TQM860L_80MHz_config 1741 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1742 interface 1743 1744 make TQM860L_FEC_80MHz_config 1745 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1746 1747 make TQM823L_LCD_config 1748 - will configure for a TQM823L with U-Boot console on LCD 1749 1750 make TQM823L_LCD_80MHz_config 1751 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1752 1753 etc. 1754 1755 1756 1757Finally, type "make all", and you should get some working U-Boot 1758images ready for downlod to / installation on your system: 1759 1760- "u-boot.bin" is a raw binary image 1761- "u-boot" is an image in ELF binary format 1762- "u-boot.srec" is in Motorola S-Record format 1763 1764 1765Please be aware that the Makefiles assume you are using GNU make, so 1766for instance on NetBSD you might need to use "gmake" instead of 1767native "make". 1768 1769 1770If the system board that you have is not listed, then you will need 1771to port U-Boot to your hardware platform. To do this, follow these 1772steps: 1773 17741. Add a new configuration option for your board to the toplevel 1775 "Makefile", using the existing entries as examples. 17762. Create a new directory to hold your board specific code. Add any 1777 files you need. 17783. If you're porting U-Boot to a new CPU, then also create a new 1779 directory to hold your CPU specific code. Add any files you need. 17804. Run "make config_name" with your new name. 17815. Type "make", and you should get a working "u-boot.srec" file 1782 to be installed on your target system. 1783 [Of course, this last step is much harder than it sounds.] 1784 1785 1786Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1787============================================================== 1788 1789If you have modified U-Boot sources (for instance added a new board 1790or support for new devices, a new CPU, etc.) you are expected to 1791provide feedback to the other developers. The feedback normally takes 1792the form of a "patch", i. e. a context diff against a certain (latest 1793official or latest in CVS) version of U-Boot sources. 1794 1795But before you submit such a patch, please verify that your modifi- 1796cation did not break existing code. At least make sure that *ALL* of 1797the supported boards compile WITHOUT ANY compiler warnings. To do so, 1798just run the "MAKEALL" script, which will configure and build U-Boot 1799for ALL supported system. Be warned, this will take a while. You can 1800select which (cross) compiler to use py passing a `CROSS_COMPILE' 1801environment variable to the script, i. e. to use the cross tools from 1802MontaVista's Hard Hat Linux you can type 1803 1804 CROSS_COMPILE=ppc_8xx- MAKEALL 1805 1806or to build on a native PowerPC system you can type 1807 1808 CROSS_COMPILE=' ' MAKEALL 1809 1810See also "U-Boot Porting Guide" below. 1811 1812 1813 1814Monitor Commands - Overview: 1815============================ 1816 1817go - start application at address 'addr' 1818run - run commands in an environment variable 1819bootm - boot application image from memory 1820bootp - boot image via network using BootP/TFTP protocol 1821tftpboot- boot image via network using TFTP protocol 1822 and env variables "ipaddr" and "serverip" 1823 (and eventually "gatewayip") 1824rarpboot- boot image via network using RARP/TFTP protocol 1825diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1826loads - load S-Record file over serial line 1827loadb - load binary file over serial line (kermit mode) 1828md - memory display 1829mm - memory modify (auto-incrementing) 1830nm - memory modify (constant address) 1831mw - memory write (fill) 1832cp - memory copy 1833cmp - memory compare 1834crc32 - checksum calculation 1835imd - i2c memory display 1836imm - i2c memory modify (auto-incrementing) 1837inm - i2c memory modify (constant address) 1838imw - i2c memory write (fill) 1839icrc32 - i2c checksum calculation 1840iprobe - probe to discover valid I2C chip addresses 1841iloop - infinite loop on address range 1842isdram - print SDRAM configuration information 1843sspi - SPI utility commands 1844base - print or set address offset 1845printenv- print environment variables 1846setenv - set environment variables 1847saveenv - save environment variables to persistent storage 1848protect - enable or disable FLASH write protection 1849erase - erase FLASH memory 1850flinfo - print FLASH memory information 1851bdinfo - print Board Info structure 1852iminfo - print header information for application image 1853coninfo - print console devices and informations 1854ide - IDE sub-system 1855loop - infinite loop on address range 1856mtest - simple RAM test 1857icache - enable or disable instruction cache 1858dcache - enable or disable data cache 1859reset - Perform RESET of the CPU 1860echo - echo args to console 1861version - print monitor version 1862help - print online help 1863? - alias for 'help' 1864 1865 1866Monitor Commands - Detailed Description: 1867======================================== 1868 1869TODO. 1870 1871For now: just type "help <command>". 1872 1873 1874Environment Variables: 1875====================== 1876 1877U-Boot supports user configuration using Environment Variables which 1878can be made persistent by saving to Flash memory. 1879 1880Environment Variables are set using "setenv", printed using 1881"printenv", and saved to Flash using "saveenv". Using "setenv" 1882without a value can be used to delete a variable from the 1883environment. As long as you don't save the environment you are 1884working with an in-memory copy. In case the Flash area containing the 1885environment is erased by accident, a default environment is provided. 1886 1887Some configuration options can be set using Environment Variables: 1888 1889 baudrate - see CONFIG_BAUDRATE 1890 1891 bootdelay - see CONFIG_BOOTDELAY 1892 1893 bootcmd - see CONFIG_BOOTCOMMAND 1894 1895 bootargs - Boot arguments when booting an RTOS image 1896 1897 bootfile - Name of the image to load with TFTP 1898 1899 autoload - if set to "no" (any string beginning with 'n'), 1900 "bootp" will just load perform a lookup of the 1901 configuration from the BOOTP server, but not try to 1902 load any image using TFTP 1903 1904 autostart - if set to "yes", an image loaded using the "bootp", 1905 "rarpboot", "tftpboot" or "diskboot" commands will 1906 be automatically started (by internally calling 1907 "bootm") 1908 1909 initrd_high - restrict positioning of initrd images: 1910 If this variable is not set, initrd images will be 1911 copied to the highest possible address in RAM; this 1912 is usually what you want since it allows for 1913 maximum initrd size. If for some reason you want to 1914 make sure that the initrd image is loaded below the 1915 CFG_BOOTMAPSZ limit, you can set this environment 1916 variable to a value of "no" or "off" or "0". 1917 Alternatively, you can set it to a maximum upper 1918 address to use (U-Boot will still check that it 1919 does not overwrite the U-Boot stack and data). 1920 1921 For instance, when you have a system with 16 MB 1922 RAM, and want to reseve 4 MB from use by Linux, 1923 you can do this by adding "mem=12M" to the value of 1924 the "bootargs" variable. However, now you must make 1925 sure, that the initrd image is placed in the first 1926 12 MB as well - this can be done with 1927 1928 setenv initrd_high 00c00000 1929 1930 ipaddr - IP address; needed for tftpboot command 1931 1932 loadaddr - Default load address for commands like "bootp", 1933 "rarpboot", "tftpboot" or "diskboot" 1934 1935 loads_echo - see CONFIG_LOADS_ECHO 1936 1937 serverip - TFTP server IP address; needed for tftpboot command 1938 1939 bootretry - see CONFIG_BOOT_RETRY_TIME 1940 1941 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1942 1943 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1944 1945 1946The following environment variables may be used and automatically 1947updated by the network boot commands ("bootp" and "rarpboot"), 1948depending the information provided by your boot server: 1949 1950 bootfile - see above 1951 dnsip - IP address of your Domain Name Server 1952 gatewayip - IP address of the Gateway (Router) to use 1953 hostname - Target hostname 1954 ipaddr - see above 1955 netmask - Subnet Mask 1956 rootpath - Pathname of the root filesystem on the NFS server 1957 serverip - see above 1958 1959 1960There are two special Environment Variables: 1961 1962 serial# - contains hardware identification information such 1963 as type string and/or serial number 1964 ethaddr - Ethernet address 1965 1966These variables can be set only once (usually during manufacturing of 1967the board). U-Boot refuses to delete or overwrite these variables 1968once they have been set once. 1969 1970 1971Please note that changes to some configuration parameters may take 1972only effect after the next boot (yes, that's just like Windoze :-). 1973 1974 1975Note for Redundant Ethernet Interfaces: 1976======================================= 1977 1978Some boards come with redundand ethernet interfaces; U-Boot supports 1979such configurations and is capable of automatic selection of a 1980"working" interface when needed. MAC assignemnt works as follows: 1981 1982Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1983MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1984"eth1addr" (=>eth1), "eth2addr", ... 1985 1986If the network interface stores some valid MAC address (for instance 1987in SROM), this is used as default address if there is NO correspon- 1988ding setting in the environment; if the corresponding environment 1989variable is set, this overrides the settings in the card; that means: 1990 1991o If the SROM has a valid MAC address, and there is no address in the 1992 environment, the SROM's address is used. 1993 1994o If there is no valid address in the SROM, and a definition in the 1995 environment exists, then the value from the environment variable is 1996 used. 1997 1998o If both the SROM and the environment contain a MAC address, and 1999 both addresses are the same, this MAC address is used. 2000 2001o If both the SROM and the environment contain a MAC address, and the 2002 addresses differ, the value from the environment is used and a 2003 warning is printed. 2004 2005o If neither SROM nor the environment contain a MAC address, an error 2006 is raised. 2007 2008 2009 2010Image Formats: 2011============== 2012 2013The "boot" commands of this monitor operate on "image" files which 2014can be basicly anything, preceeded by a special header; see the 2015definitions in include/image.h for details; basicly, the header 2016defines the following image properties: 2017 2018* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2019 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2020 LynxOS, pSOS, QNX; 2021 Currently supported: Linux, NetBSD, VxWorks, QNX). 2022* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2023 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2024 Currently supported: PowerPC). 2025* Compression Type (Provisions for uncompressed, gzip, bzip2; 2026 Currently supported: uncompressed, gzip). 2027* Load Address 2028* Entry Point 2029* Image Name 2030* Image Timestamp 2031 2032The header is marked by a special Magic Number, and both the header 2033and the data portions of the image are secured against corruption by 2034CRC32 checksums. 2035 2036 2037Linux Support: 2038============== 2039 2040Although U-Boot should support any OS or standalone application 2041easily, Linux has always been in the focus during the design of 2042U-Boot. 2043 2044U-Boot includes many features that so far have been part of some 2045special "boot loader" code within the Linux kernel. Also, any 2046"initrd" images to be used are no longer part of one big Linux image; 2047instead, kernel and "initrd" are separate images. This implementation 2048serves serveral purposes: 2049 2050- the same features can be used for other OS or standalone 2051 applications (for instance: using compressed images to reduce the 2052 Flash memory footprint) 2053 2054- it becomes much easier to port new Linux kernel versions because 2055 lots of low-level, hardware dependend stuff are done by U-Boot 2056 2057- the same Linux kernel image can now be used with different "initrd" 2058 images; of course this also means that different kernel images can 2059 be run with the same "initrd". This makes testing easier (you don't 2060 have to build a new "zImage.initrd" Linux image when you just 2061 change a file in your "initrd"). Also, a field-upgrade of the 2062 software is easier now. 2063 2064 2065Linux HOWTO: 2066============ 2067 2068Porting Linux to U-Boot based systems: 2069--------------------------------------- 2070 2071U-Boot cannot save you from doing all the necessary modifications to 2072configure the Linux device drivers for use with your target hardware 2073(no, we don't intend to provide a full virtual machine interface to 2074Linux :-). 2075 2076But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2077 2078Just make sure your machine specific header file (for instance 2079include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2080Information structure as we define in include/u-boot.h, and make 2081sure that your definition of IMAP_ADDR uses the same value as your 2082U-Boot configuration in CFG_IMMR. 2083 2084 2085Configuring the Linux kernel: 2086----------------------------- 2087 2088No specific requirements for U-Boot. Make sure you have some root 2089device (initial ramdisk, NFS) for your target system. 2090 2091 2092Building a Linux Image: 2093----------------------- 2094 2095With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2096not used. If you use recent kernel source, a new build target 2097"uImage" will exist which automatically builds an image usable by 2098U-Boot. Most older kernels also have support for a "pImage" target, 2099which was introduced for our predecessor project PPCBoot and uses a 2100100% compatible format. 2101 2102Example: 2103 2104 make TQM850L_config 2105 make oldconfig 2106 make dep 2107 make uImage 2108 2109The "uImage" build target uses a special tool (in 'tools/mkimage') to 2110encapsulate a compressed Linux kernel image with header information, 2111CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2112 2113* build a standard "vmlinux" kernel image (in ELF binary format): 2114 2115* convert the kernel into a raw binary image: 2116 2117 ${CROSS_COMPILE}-objcopy -O binary \ 2118 -R .note -R .comment \ 2119 -S vmlinux linux.bin 2120 2121* compress the binary image: 2122 2123 gzip -9 linux.bin 2124 2125* package compressed binary image for U-Boot: 2126 2127 mkimage -A ppc -O linux -T kernel -C gzip \ 2128 -a 0 -e 0 -n "Linux Kernel Image" \ 2129 -d linux.bin.gz uImage 2130 2131 2132The "mkimage" tool can also be used to create ramdisk images for use 2133with U-Boot, either separated from the Linux kernel image, or 2134combined into one file. "mkimage" encapsulates the images with a 64 2135byte header containing information about target architecture, 2136operating system, image type, compression method, entry points, time 2137stamp, CRC32 checksums, etc. 2138 2139"mkimage" can be called in two ways: to verify existing images and 2140print the header information, or to build new images. 2141 2142In the first form (with "-l" option) mkimage lists the information 2143contained in the header of an existing U-Boot image; this includes 2144checksum verification: 2145 2146 tools/mkimage -l image 2147 -l ==> list image header information 2148 2149The second form (with "-d" option) is used to build a U-Boot image 2150from a "data file" which is used as image payload: 2151 2152 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2153 -n name -d data_file image 2154 -A ==> set architecture to 'arch' 2155 -O ==> set operating system to 'os' 2156 -T ==> set image type to 'type' 2157 -C ==> set compression type 'comp' 2158 -a ==> set load address to 'addr' (hex) 2159 -e ==> set entry point to 'ep' (hex) 2160 -n ==> set image name to 'name' 2161 -d ==> use image data from 'datafile' 2162 2163Right now, all Linux kernels use the same load address (0x00000000), 2164but the entry point address depends on the kernel version: 2165 2166- 2.2.x kernels have the entry point at 0x0000000C, 2167- 2.3.x and later kernels have the entry point at 0x00000000. 2168 2169So a typical call to build a U-Boot image would read: 2170 2171 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2172 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2173 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2174 > examples/uImage.TQM850L 2175 Image Name: 2.4.4 kernel for TQM850L 2176 Created: Wed Jul 19 02:34:59 2000 2177 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2178 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2179 Load Address: 0x00000000 2180 Entry Point: 0x00000000 2181 2182To verify the contents of the image (or check for corruption): 2183 2184 -> tools/mkimage -l examples/uImage.TQM850L 2185 Image Name: 2.4.4 kernel for TQM850L 2186 Created: Wed Jul 19 02:34:59 2000 2187 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2188 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2189 Load Address: 0x00000000 2190 Entry Point: 0x00000000 2191 2192NOTE: for embedded systems where boot time is critical you can trade 2193speed for memory and install an UNCOMPRESSED image instead: this 2194needs more space in Flash, but boots much faster since it does not 2195need to be uncompressed: 2196 2197 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2198 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2199 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2200 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2201 > examples/uImage.TQM850L-uncompressed 2202 Image Name: 2.4.4 kernel for TQM850L 2203 Created: Wed Jul 19 02:34:59 2000 2204 Image Type: PowerPC Linux Kernel Image (uncompressed) 2205 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2206 Load Address: 0x00000000 2207 Entry Point: 0x00000000 2208 2209 2210Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2211when your kernel is intended to use an initial ramdisk: 2212 2213 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2214 > -A ppc -O linux -T ramdisk -C gzip \ 2215 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2216 Image Name: Simple Ramdisk Image 2217 Created: Wed Jan 12 14:01:50 2000 2218 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2219 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2220 Load Address: 0x00000000 2221 Entry Point: 0x00000000 2222 2223 2224Installing a Linux Image: 2225------------------------- 2226 2227To downloading a U-Boot image over the serial (console) interface, 2228you must convert the image to S-Record format: 2229 2230 objcopy -I binary -O srec examples/image examples/image.srec 2231 2232The 'objcopy' does not understand the information in the U-Boot 2233image header, so the resulting S-Record file will be relative to 2234address 0x00000000. To load it to a given address, you need to 2235specify the target address as 'offset' parameter with the 'loads' 2236command. 2237 2238Example: install the image to address 0x40100000 (which on the 2239TQM8xxL is in the first Flash bank): 2240 2241 => erase 40100000 401FFFFF 2242 2243 .......... done 2244 Erased 8 sectors 2245 2246 => loads 40100000 2247 ## Ready for S-Record download ... 2248 ~>examples/image.srec 2249 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2250 ... 2251 15989 15990 15991 15992 2252 [file transfer complete] 2253 [connected] 2254 ## Start Addr = 0x00000000 2255 2256 2257You can check the success of the download using the 'iminfo' command; 2258this includes a checksum verification so you can be sure no data 2259corruption happened: 2260 2261 => imi 40100000 2262 2263 ## Checking Image at 40100000 ... 2264 Image Name: 2.2.13 for initrd on TQM850L 2265 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2266 Data Size: 335725 Bytes = 327 kB = 0 MB 2267 Load Address: 00000000 2268 Entry Point: 0000000c 2269 Verifying Checksum ... OK 2270 2271 2272 2273Boot Linux: 2274----------- 2275 2276The "bootm" command is used to boot an application that is stored in 2277memory (RAM or Flash). In case of a Linux kernel image, the contents 2278of the "bootargs" environment variable is passed to the kernel as 2279parameters. You can check and modify this variable using the 2280"printenv" and "setenv" commands: 2281 2282 2283 => printenv bootargs 2284 bootargs=root=/dev/ram 2285 2286 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2287 2288 => printenv bootargs 2289 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2290 2291 => bootm 40020000 2292 ## Booting Linux kernel at 40020000 ... 2293 Image Name: 2.2.13 for NFS on TQM850L 2294 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2295 Data Size: 381681 Bytes = 372 kB = 0 MB 2296 Load Address: 00000000 2297 Entry Point: 0000000c 2298 Verifying Checksum ... OK 2299 Uncompressing Kernel Image ... OK 2300 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 2301 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2302 time_init: decrementer frequency = 187500000/60 2303 Calibrating delay loop... 49.77 BogoMIPS 2304 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2305 ... 2306 2307If you want to boot a Linux kernel with initial ram disk, you pass 2308the memory addreses of both the kernel and the initrd image (PPBCOOT 2309format!) to the "bootm" command: 2310 2311 => imi 40100000 40200000 2312 2313 ## Checking Image at 40100000 ... 2314 Image Name: 2.2.13 for initrd on TQM850L 2315 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2316 Data Size: 335725 Bytes = 327 kB = 0 MB 2317 Load Address: 00000000 2318 Entry Point: 0000000c 2319 Verifying Checksum ... OK 2320 2321 ## Checking Image at 40200000 ... 2322 Image Name: Simple Ramdisk Image 2323 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2324 Data Size: 566530 Bytes = 553 kB = 0 MB 2325 Load Address: 00000000 2326 Entry Point: 00000000 2327 Verifying Checksum ... OK 2328 2329 => bootm 40100000 40200000 2330 ## Booting Linux kernel at 40100000 ... 2331 Image Name: 2.2.13 for initrd on TQM850L 2332 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2333 Data Size: 335725 Bytes = 327 kB = 0 MB 2334 Load Address: 00000000 2335 Entry Point: 0000000c 2336 Verifying Checksum ... OK 2337 Uncompressing Kernel Image ... OK 2338 ## Loading RAMDisk Image at 40200000 ... 2339 Image Name: Simple Ramdisk Image 2340 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2341 Data Size: 566530 Bytes = 553 kB = 0 MB 2342 Load Address: 00000000 2343 Entry Point: 00000000 2344 Verifying Checksum ... OK 2345 Loading Ramdisk ... OK 2346 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 2347 Boot arguments: root=/dev/ram 2348 time_init: decrementer frequency = 187500000/60 2349 Calibrating delay loop... 49.77 BogoMIPS 2350 ... 2351 RAMDISK: Compressed image found at block 0 2352 VFS: Mounted root (ext2 filesystem). 2353 2354 bash# 2355 2356 2357Standalone HOWTO: 2358================= 2359 2360One of the features of U-Boot is that you can dynamically load and 2361run "standalone" applications, which can use some resources of 2362U-Boot like console I/O functions or interrupt services. 2363 2364Two simple examples are included with the sources: 2365 2366"Hello World" Demo: 2367------------------- 2368 2369'examples/hello_world.c' contains a small "Hello World" Demo 2370application; it is automatically compiled when you build U-Boot. 2371It's configured to run at address 0x00040004, so you can play with it 2372like that: 2373 2374 => loads 2375 ## Ready for S-Record download ... 2376 ~>examples/hello_world.srec 2377 1 2 3 4 5 6 7 8 9 10 11 ... 2378 [file transfer complete] 2379 [connected] 2380 ## Start Addr = 0x00040004 2381 2382 => go 40004 Hello World! This is a test. 2383 ## Starting application at 0x00040004 ... 2384 Hello World 2385 argc = 7 2386 argv[0] = "40004" 2387 argv[1] = "Hello" 2388 argv[2] = "World!" 2389 argv[3] = "This" 2390 argv[4] = "is" 2391 argv[5] = "a" 2392 argv[6] = "test." 2393 argv[7] = "<NULL>" 2394 Hit any key to exit ... 2395 2396 ## Application terminated, rc = 0x0 2397 2398Another example, which demonstrates how to register a CPM interrupt 2399handler with the U-Boot code, can be found in 'examples/timer.c'. 2400Here, a CPM timer is set up to generate an interrupt every second. 2401The interrupt service routine is trivial, just printing a '.' 2402character, but this is just a demo program. The application can be 2403controlled by the following keys: 2404 2405 ? - print current values og the CPM Timer registers 2406 b - enable interrupts and start timer 2407 e - stop timer and disable interrupts 2408 q - quit application 2409 2410 => loads 2411 ## Ready for S-Record download ... 2412 ~>examples/timer.srec 2413 1 2 3 4 5 6 7 8 9 10 11 ... 2414 [file transfer complete] 2415 [connected] 2416 ## Start Addr = 0x00040004 2417 2418 => go 40004 2419 ## Starting application at 0x00040004 ... 2420 TIMERS=0xfff00980 2421 Using timer 1 2422 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2423 2424Hit 'b': 2425 [q, b, e, ?] Set interval 1000000 us 2426 Enabling timer 2427Hit '?': 2428 [q, b, e, ?] ........ 2429 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2430Hit '?': 2431 [q, b, e, ?] . 2432 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2433Hit '?': 2434 [q, b, e, ?] . 2435 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2436Hit '?': 2437 [q, b, e, ?] . 2438 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2439Hit 'e': 2440 [q, b, e, ?] ...Stopping timer 2441Hit 'q': 2442 [q, b, e, ?] ## Application terminated, rc = 0x0 2443 2444 2445NetBSD Notes: 2446============= 2447 2448Starting at version 0.9.2, U-Boot supports NetBSD both as host 2449(build U-Boot) and target system (boots NetBSD/mpc8xx). 2450 2451Building requires a cross environment; it is known to work on 2452NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2453need gmake since the Makefiles are not compatible with BSD make). 2454Note that the cross-powerpc package does not install include files; 2455attempting to build U-Boot will fail because <machine/ansi.h> is 2456missing. This file has to be installed and patched manually: 2457 2458 # cd /usr/pkg/cross/powerpc-netbsd/include 2459 # mkdir powerpc 2460 # ln -s powerpc machine 2461 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2462 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2463 2464Native builds *don't* work due to incompatibilities between native 2465and U-Boot include files. 2466 2467Booting assumes that (the first part of) the image booted is a 2468stage-2 loader which in turn loads and then invokes the kernel 2469proper. Loader sources will eventually appear in the NetBSD source 2470tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2471meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2472details. 2473 2474 2475Implementation Internals: 2476========================= 2477 2478The following is not intended to be a complete description of every 2479implementation detail. However, it should help to understand the 2480inner workings of U-Boot and make it easier to port it to custom 2481hardware. 2482 2483 2484Initial Stack, Global Data: 2485--------------------------- 2486 2487The implementation of U-Boot is complicated by the fact that U-Boot 2488starts running out of ROM (flash memory), usually without access to 2489system RAM (because the memory controller is not initialized yet). 2490This means that we don't have writable Data or BSS segments, and BSS 2491is not initialized as zero. To be able to get a C environment working 2492at all, we have to allocate at least a minimal stack. Implementation 2493options for this are defined and restricted by the CPU used: Some CPU 2494models provide on-chip memory (like the IMMR area on MPC8xx and 2495MPC826x processors), on others (parts of) the data cache can be 2496locked as (mis-) used as memory, etc. 2497 2498It is essential to remember this, since it has some impact on the C 2499code for the initialization procedures: 2500 2501* Initialized global data (data segment) is read-only. Do not attempt 2502 to write it. 2503 2504* Do not use any unitialized global data (or implicitely initialized 2505 as zero data - BSS segment) at all - this is undefined, initiali- 2506 zation is performed later (when relocationg to RAM). 2507 2508* Stack space is very limited. Avoid big data buffers or things like 2509 that. 2510 2511Having only the stack as writable memory limits means we cannot use 2512normal global data to share information beween the code. But it 2513turned out that the implementation of U-Boot can be greatly 2514simplified by making a global data structure (gd_t) available to all 2515functions. We could pass a pointer to this data as argument to _all_ 2516functions, but this would bloat the code. Instead we use a feature of 2517the GCC compiler (Global Register Variables) to share the data: we 2518place a pointer (gd) to the global data into a register which we 2519reserve for this purpose. 2520 2521When chosing a register for such a purpose we are restricted by the 2522relevant (E)ABI specifications for the current architecture, and by 2523GCC's implementation. 2524 2525For PowerPC, the following registers have specific use: 2526 R1: stack pointer 2527 R2: TOC pointer 2528 R3-R4: parameter passing and return values 2529 R5-R10: parameter passing 2530 R13: small data area pointer 2531 R30: GOT pointer 2532 R31: frame pointer 2533 2534 (U-Boot also uses R14 as internal GOT pointer.) 2535 2536 ==> U-Boot will use R29 to hold a pointer to the global data 2537 2538 Note: on PPC, we could use a static initializer (since the 2539 address of the global data structure is known at compile time), 2540 but it turned out that reserving a register results in somewhat 2541 smaller code - although the code savings are not that big (on 2542 average for all boards 752 bytes for the whole U-Boot image, 2543 624 text + 127 data). 2544 2545On ARM, the following registers are used: 2546 2547 R0: function argument word/integer result 2548 R1-R3: function argument word 2549 R9: GOT pointer 2550 R10: stack limit (used only if stack checking if enabled) 2551 R11: argument (frame) pointer 2552 R12: temporary workspace 2553 R13: stack pointer 2554 R14: link register 2555 R15: program counter 2556 2557 ==> U-Boot will use R8 to hold a pointer to the global data 2558 2559 2560 2561Memory Management: 2562------------------ 2563 2564U-Boot runs in system state and uses physical addresses, i.e. the 2565MMU is not used either for address mapping nor for memory protection. 2566 2567The available memory is mapped to fixed addresses using the memory 2568controller. In this process, a contiguous block is formed for each 2569memory type (Flash, SDRAM, SRAM), even when it consists of several 2570physical memory banks. 2571 2572U-Boot is installed in the first 128 kB of the first Flash bank (on 2573TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2574booting and sizing and initializing DRAM, the code relocates itself 2575to the upper end of DRAM. Immediately below the U-Boot code some 2576memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2577configuration setting]. Below that, a structure with global Board 2578Info data is placed, followed by the stack (growing downward). 2579 2580Additionally, some exception handler code is copied to the low 8 kB 2581of DRAM (0x00000000 ... 0x00001FFF). 2582 2583So a typical memory configuration with 16 MB of DRAM could look like 2584this: 2585 2586 0x0000 0000 Exception Vector code 2587 : 2588 0x0000 1FFF 2589 0x0000 2000 Free for Application Use 2590 : 2591 : 2592 2593 : 2594 : 2595 0x00FB FF20 Monitor Stack (Growing downward) 2596 0x00FB FFAC Board Info Data and permanent copy of global data 2597 0x00FC 0000 Malloc Arena 2598 : 2599 0x00FD FFFF 2600 0x00FE 0000 RAM Copy of Monitor Code 2601 ... eventually: LCD or video framebuffer 2602 ... eventually: pRAM (Protected RAM - unchanged by reset) 2603 0x00FF FFFF [End of RAM] 2604 2605 2606System Initialization: 2607---------------------- 2608 2609In the reset configuration, U-Boot starts at the reset entry point 2610(on most PowerPC systens at address 0x00000100). Because of the reset 2611configuration for CS0# this is a mirror of the onboard Flash memory. 2612To be able to re-map memory U-Boot then jumps to it's link address. 2613To be able to implement the initialization code in C, a (small!) 2614initial stack is set up in the internal Dual Ported RAM (in case CPUs 2615which provide such a feature like MPC8xx or MPC8260), or in a locked 2616part of the data cache. After that, U-Boot initializes the CPU core, 2617the caches and the SIU. 2618 2619Next, all (potentially) available memory banks are mapped using a 2620preliminary mapping. For example, we put them on 512 MB boundaries 2621(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2622on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2623programmed for SDRAM access. Using the temporary configuration, a 2624simple memory test is run that determines the size of the SDRAM 2625banks. 2626 2627When there is more than one SDRAM bank, and the banks are of 2628different size, the larger is mapped first. For equal size, the first 2629bank (CS2#) is mapped first. The first mapping is always for address 26300x00000000, with any additional banks following immediately to create 2631contiguous memory starting from 0. 2632 2633Then, the monitor installs itself at the upper end of the SDRAM area 2634and allocates memory for use by malloc() and for the global Board 2635Info data; also, the exception vector code is copied to the low RAM 2636pages, and the final stack is set up. 2637 2638Only after this relocation will you have a "normal" C environment; 2639until that you are restricted in several ways, mostly because you are 2640running from ROM, and because the code will have to be relocated to a 2641new address in RAM. 2642 2643 2644U-Boot Porting Guide: 2645---------------------- 2646 2647[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2648list, October 2002] 2649 2650 2651int main (int argc, char *argv[]) 2652{ 2653 sighandler_t no_more_time; 2654 2655 signal (SIGALRM, no_more_time); 2656 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2657 2658 if (available_money > available_manpower) { 2659 pay consultant to port U-Boot; 2660 return 0; 2661 } 2662 2663 Download latest U-Boot source; 2664 2665 Subscribe to u-boot-users mailing list; 2666 2667 if (clueless) { 2668 email ("Hi, I am new to U-Boot, how do I get started?"); 2669 } 2670 2671 while (learning) { 2672 Read the README file in the top level directory; 2673 Read http://www.denx.de/re/DPLG.html 2674 Read the source, Luke; 2675 } 2676 2677 if (available_money > toLocalCurrency ($2500)) { 2678 Buy a BDI2000; 2679 } else { 2680 Add a lot of aggravation and time; 2681 } 2682 2683 Create your own board support subdirectory; 2684 2685 Create your own board config file; 2686 2687 while (!running) { 2688 do { 2689 Add / modify source code; 2690 } until (compiles); 2691 Debug; 2692 if (clueless) 2693 email ("Hi, I am having problems..."); 2694 } 2695 Send patch file to Wolfgang; 2696 2697 return 0; 2698} 2699 2700void no_more_time (int sig) 2701{ 2702 hire_a_guru(); 2703} 2704 2705 2706 2707Coding Standards: 2708----------------- 2709 2710All contributions to U-Boot should conform to the Linux kernel 2711coding style; see the file "Documentation/CodingStyle" in your Linux 2712kernel source directory. 2713 2714Please note that U-Boot is implemented in C (and to some small parts 2715in Assembler); no C++ is used, so please do not use C++ style 2716comments (//) in your code. 2717 2718Submissions which do not conform to the standards may be returned 2719with a request to reformat the changes. 2720 2721 2722Submitting Patches: 2723------------------- 2724 2725Since the number of patches for U-Boot is growing, we need to 2726establish some rules. Submissions which do not conform to these rules 2727may be rejected, even when they contain important and valuable stuff. 2728 2729 2730When you send a patch, please include the following information with 2731it: 2732 2733* For bug fixes: a description of the bug and how your patch fixes 2734 this bug. Please try to include a way of demonstrating that the 2735 patch actually fixes something. 2736 2737* For new features: a description of the feature and your 2738 implementation. 2739 2740* A CHANGELOG entry as plaintext (separate from the patch) 2741 2742* For major contributions, your entry to the CREDITS file 2743 2744* When you add support for a new board, don't forget to add this 2745 board to the MAKEALL script, too. 2746 2747* If your patch adds new configuration options, don't forget to 2748 document these in the README file. 2749 2750* The patch itself. If you are accessing the CVS repository use "cvs 2751 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2752 version of diff does not support these options, then get the latest 2753 version of GNU diff. 2754 2755 We accept patches as plain text, MIME attachments or as uuencoded 2756 gzipped text. 2757 2758Notes: 2759 2760* Before sending the patch, run the MAKEALL script on your patched 2761 source tree and make sure that no errors or warnings are reported 2762 for any of the boards. 2763 2764* Keep your modifications to the necessary minimum: A patch 2765 containing several unrelated changes or arbitrary reformats will be 2766 returned with a request to re-formatting / split it. 2767 2768* If you modify existing code, make sure that your new code does not 2769 add to the memory footprint of the code ;-) Small is beautiful! 2770 When adding new features, these should compile conditionally only 2771 (using #ifdef), and the resulting code with the new feature 2772 disabled must not need more memory than the old code without your 2773 modification. 2774