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 107Directory Hierarchy: 108==================== 109 110- board Board dependend files 111- common Misc architecture independend functions 112- cpu CPU specific files 113- disk Code for disk drive partition handling 114- doc Documentation (don't expect too much) 115- drivers Common used device drivers 116- dtt Digital Thermometer and Thermostat drivers 117- examples Example code for standalone applications, etc. 118- include Header Files 119- disk Harddisk interface code 120- net Networking code 121- ppc Files generic to PowerPC architecture 122- post Power On Self Test 123- post/arch Symlink to architecture specific Power On Self Test 124- post/arch-ppc PowerPC architecture specific Power On Self Test 125- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test 126- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test 127- rtc Real Time Clock drivers 128- tools Tools to build S-Record or U-Boot images, etc. 129 130- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 131- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs 132- cpu/mpc824x Files specific to Motorola MPC824x CPUs 133- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 134- cpu/ppc4xx Files specific to IBM 4xx CPUs 135 136- board/RPXClassic 137 Files specific to RPXClassic boards 138- board/RPXlite Files specific to RPXlite boards 139- board/c2mon Files specific to c2mon boards 140- board/cogent Files specific to Cogent boards 141 (need further configuration) 142 Files specific to CPCIISER4 boards 143- board/cpu86 Files specific to CPU86 boards 144- board/cray/ Files specific to boards manufactured by Cray 145- board/cray/L1 Files specific to L1 boards 146- board/cu824 Files specific to CU824 boards 147- board/ebony Files specific to IBM Ebony board 148- board/eric Files specific to ERIC boards 149- board/esd/ Files specific to boards manufactured by ESD 150- board/esd/adciop Files specific to ADCIOP boards 151- board/esd/ar405 Files specific to AR405 boards 152- board/esd/canbt Files specific to CANBT boards 153- board/esd/cpci405 Files specific to CPCI405 boards 154- board/esd/cpciiser4 Files specific to CPCIISER4 boards 155- board/esd/common Common files for ESD boards 156- board/esd/dasa_sim Files specific to DASA_SIM boards 157- board/esd/du405 Files specific to DU405 boards 158- board/esd/ocrtc Files specific to OCRTC boards 159- board/esd/pci405 Files specific to PCI405 boards 160- board/esteem192e 161 Files specific to ESTEEM192E boards 162- board/etx094 Files specific to ETX_094 boards 163- board/evb64260 164 Files specific to EVB64260 boards 165- board/fads Files specific to FADS boards 166- board/flagadm Files specific to FLAGADM boards 167- board/gen860t Files specific to GEN860T boards 168- board/genietv Files specific to GENIETV boards 169- board/gth Files specific to GTH boards 170- board/hermes Files specific to HERMES boards 171- board/hymod Files specific to HYMOD boards 172- board/icu862 Files specific to ICU862 boards 173- board/ip860 Files specific to IP860 boards 174- board/iphase4539 175 Files specific to Interphase4539 boards 176- board/ivm Files specific to IVMS8/IVML24 boards 177- board/lantec Files specific to LANTEC boards 178- board/lwmon Files specific to LWMON boards 179- board/mbx8xx Files specific to MBX boards 180- board/mpc8260ads 181 Files specific to MMPC8260ADS boards 182- board/mpl/ Files specific to boards manufactured by MPL 183- board/mpl/common Common files for MPL boards 184- board/mpl/pip405 Files specific to PIP405 boards 185- board/mpl/mip405 Files specific to MIP405 boards 186- board/musenki Files specific to MUSEKNI boards 187- board/mvs1 Files specific to MVS1 boards 188- board/nx823 Files specific to NX823 boards 189- board/oxc Files specific to OXC boards 190- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 191- board/pm826 Files specific to PM826 boards 192- board/ppmc8260 193 Files specific to PPMC8260 boards 194- board/rpxsuper 195 Files specific to RPXsuper boards 196- board/rsdproto 197 Files specific to RSDproto boards 198- board/sandpoint 199 Files specific to Sandpoint boards 200- board/sbc8260 Files specific to SBC8260 boards 201- board/sacsng Files specific to SACSng boards 202- board/siemens Files specific to boards manufactured by Siemens AG 203- board/siemens/CCM Files specific to CCM boards 204- board/siemens/IAD210 Files specific to IAD210 boards 205- board/siemens/SCM Files specific to SCM boards 206- board/siemens/pcu_e Files specific to PCU_E boards 207- board/sixnet Files specific to SIXNET boards 208- board/spd8xx Files specific to SPD8xxTS boards 209- board/tqm8260 Files specific to TQM8260 boards 210- board/tqm8xx Files specific to TQM8xxL boards 211- board/w7o Files specific to W7O boards 212- board/walnut405 213 Files specific to Walnut405 boards 214- board/westel/ Files specific to boards manufactured by Westel Wireless 215- board/westel/amx860 Files specific to AMX860 boards 216- board/utx8245 Files specific to UTX8245 boards 217 218Software Configuration: 219======================= 220 221Configuration is usually done using C preprocessor defines; the 222rationale behind that is to avoid dead code whenever possible. 223 224There are two classes of configuration variables: 225 226* Configuration _OPTIONS_: 227 These are selectable by the user and have names beginning with 228 "CONFIG_". 229 230* Configuration _SETTINGS_: 231 These depend on the hardware etc. and should not be meddled with if 232 you don't know what you're doing; they have names beginning with 233 "CFG_". 234 235Later we will add a configuration tool - probably similar to or even 236identical to what's used for the Linux kernel. Right now, we have to 237do the configuration by hand, which means creating some symbolic 238links and editing some configuration files. We use the TQM8xxL boards 239as an example here. 240 241 242Selection of Processor Architecture and Board Type: 243--------------------------------------------------- 244 245For all supported boards there are ready-to-use default 246configurations available; just type "make <board_name>_config". 247 248Example: For a TQM823L module type: 249 250 cd u-boot 251 make TQM823L_config 252 253For the Cogent platform, you need to specify the cpu type as well; 254e.g. "make cogent_mpc8xx_config". And also configure the cogent 255directory according to the instructions in cogent/README. 256 257 258Configuration Options: 259---------------------- 260 261Configuration depends on the combination of board and CPU type; all 262such information is kept in a configuration file 263"include/configs/<board_name>.h". 264 265Example: For a TQM823L module, all configuration settings are in 266"include/configs/TQM823L.h". 267 268 269Many of the options are named exactly as the corresponding Linux 270kernel configuration options. The intention is to make it easier to 271build a config tool - later. 272 273 274The following options need to be configured: 275 276- CPU Type: Define exactly one of 277 278 PowerPC based CPUs: 279 ------------------- 280 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 281 or CONFIG_MPC824X, CONFIG_MPC8260 282 or CONFIG_IOP480 283 or CONFIG_405GP 284 or CONFIG_440 285 or CONFIG_MPC74xx 286 287 ARM based CPUs: 288 --------------- 289 CONFIG_SA1110 290 CONFIG_ARM7 291 CONFIG_PXA250 292 293 294- Board Type: Define exactly one of 295 296 PowerPC based boards: 297 --------------------- 298 299 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 300 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 301 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 302 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 303 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 304 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 305 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 306 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 307 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 308 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 309 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 310 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 311 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 312 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 313 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 314 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 315 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 316 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 317 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 318 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 319 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 320 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 321 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 322 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 323 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 324 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 325 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 326 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 327 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 328 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L 329 330 ARM based boards: 331 ----------------- 332 333 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 334 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 335 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 336 CONFIG_TRAB 337 338 339- CPU Module Type: (if CONFIG_COGENT is defined) 340 Define exactly one of 341 CONFIG_CMA286_60_OLD 342--- FIXME --- not tested yet: 343 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 344 CONFIG_CMA287_23, CONFIG_CMA287_50 345 346- Motherboard Type: (if CONFIG_COGENT is defined) 347 Define exactly one of 348 CONFIG_CMA101, CONFIG_CMA102 349 350- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 351 Define one or more of 352 CONFIG_CMA302 353 354- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 355 Define one or more of 356 CONFIG_LCD_HEARTBEAT - update a character position on 357 the lcd display every second with 358 a "rotator" |\-/|\-/ 359 360- MPC824X Family Member (if CONFIG_MPC824X is defined) 361 Define exactly one of 362 CONFIG_MPC8240, CONFIG_MPC8245 363 364- 8xx CPU Options: (if using an 8xx cpu) 365 Define one or more of 366 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 367 no 32KHz reference PIT/RTC clock 368 369- Clock Interface: 370 CONFIG_CLOCKS_IN_MHZ 371 372 U-Boot stores all clock information in Hz 373 internally. For binary compatibility with older Linux 374 kernels (which expect the clocks passed in the 375 bd_info data to be in MHz) the environment variable 376 "clocks_in_mhz" can be defined so that U-Boot 377 converts clock data to MHZ before passing it to the 378 Linux kernel. 379 380 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 381 "clocks_in_mhz=1" is automatically included in the 382 default environment. 383 384- Console Interface: 385 Depending on board, define exactly one serial port 386 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 387 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 388 console by defining CONFIG_8xx_CONS_NONE 389 390 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 391 port routines must be defined elsewhere 392 (i.e. serial_init(), serial_getc(), ...) 393 394 CONFIG_CFB_CONSOLE 395 Enables console device for a color framebuffer. Needs following 396 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 397 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 398 (default big endian) 399 VIDEO_HW_RECTFILL graphic chip supports 400 rectangle fill 401 (cf. smiLynxEM) 402 VIDEO_HW_BITBLT graphic chip supports 403 bit-blit (cf. smiLynxEM) 404 VIDEO_VISIBLE_COLS visible pixel columns 405 (cols=pitch) 406 VIDEO_VISIBLE_ROWS visible pixel rows 407 VIDEO_PIXEL_SIZE bytes per pixel 408 VIDEO_DATA_FORMAT graphic data format 409 (0-5, cf. cfb_console.c) 410 VIDEO_FB_ADRS framebuffer address 411 VIDEO_KBD_INIT_FCT keyboard int fct 412 (i.e. i8042_kbd_init()) 413 VIDEO_TSTC_FCT test char fct 414 (i.e. i8042_tstc) 415 VIDEO_GETC_FCT get char fct 416 (i.e. i8042_getc) 417 CONFIG_CONSOLE_CURSOR cursor drawing on/off 418 (requires blink timer 419 cf. i8042.c) 420 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 421 CONFIG_CONSOLE_TIME display time/date info in 422 upper right corner 423 (requires CFG_CMD_DATE) 424 CONFIG_VIDEO_LOGO display Linux logo in 425 upper left corner 426 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 427 linux_logo.h for logo. 428 Requires CONFIG_VIDEO_LOGO 429 CONFIG_CONSOLE_EXTRA_INFO 430 addional board info beside 431 the logo 432 433 When CONFIG_CFB_CONSOLE is defined, video console is 434 default i/o. Serial console can be forced with 435 environment 'console=serial'. 436 437- Console Baudrate: 438 CONFIG_BAUDRATE - in bps 439 Select one of the baudrates listed in 440 CFG_BAUDRATE_TABLE, see below. 441 442- Interrupt driven serial port input: 443 CONFIG_SERIAL_SOFTWARE_FIFO 444 445 PPC405GP only. 446 Use an interrupt handler for receiving data on the 447 serial port. It also enables using hardware handshake 448 (RTS/CTS) and UART's built-in FIFO. Set the number of 449 bytes the interrupt driven input buffer should have. 450 451 Set to 0 to disable this feature (this is the default). 452 This will also disable hardware handshake. 453 454- Boot Delay: CONFIG_BOOTDELAY - in seconds 455 Delay before automatically booting the default image; 456 set to -1 to disable autoboot. 457 458 See doc/README.autoboot for these options that 459 work with CONFIG_BOOTDELAY. None are required. 460 CONFIG_BOOT_RETRY_TIME 461 CONFIG_BOOT_RETRY_MIN 462 CONFIG_AUTOBOOT_KEYED 463 CONFIG_AUTOBOOT_PROMPT 464 CONFIG_AUTOBOOT_DELAY_STR 465 CONFIG_AUTOBOOT_STOP_STR 466 CONFIG_AUTOBOOT_DELAY_STR2 467 CONFIG_AUTOBOOT_STOP_STR2 468 CONFIG_ZERO_BOOTDELAY_CHECK 469 CONFIG_RESET_TO_RETRY 470 471- Autoboot Command: 472 CONFIG_BOOTCOMMAND 473 Only needed when CONFIG_BOOTDELAY is enabled; 474 define a command string that is automatically executed 475 when no character is read on the console interface 476 within "Boot Delay" after reset. 477 478 CONFIG_BOOTARGS 479 This can be used to pass arguments to the bootm 480 command. The value of CONFIG_BOOTARGS goes into the 481 environment value "bootargs". 482 483 CONFIG_RAMBOOT and CONFIG_NFSBOOT 484 The value of these goes into the environment as 485 "ramboot" and "nfsboot" respectively, and can be used 486 as a convenience, when switching between booting from 487 ram and nfs. 488 489- Pre-Boot Commands: 490 CONFIG_PREBOOT 491 492 When this option is #defined, the existence of the 493 environment variable "preboot" will be checked 494 immediately before starting the CONFIG_BOOTDELAY 495 countdown and/or running the auto-boot command resp. 496 entering interactive mode. 497 498 This feature is especially useful when "preboot" is 499 automatically generated or modified. For an example 500 see the LWMON board specific code: here "preboot" is 501 modified when the user holds down a certain 502 combination of keys on the (special) keyboard when 503 booting the systems 504 505- Serial Download Echo Mode: 506 CONFIG_LOADS_ECHO 507 If defined to 1, all characters received during a 508 serial download (using the "loads" command) are 509 echoed back. This might be needed by some terminal 510 emulations (like "cu"), but may as well just take 511 time on others. This setting #define's the initial 512 value of the "loads_echo" environment variable. 513 514- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 515 CONFIG_KGDB_BAUDRATE 516 Select one of the baudrates listed in 517 CFG_BAUDRATE_TABLE, see below. 518 519- Monitor Functions: 520 CONFIG_COMMANDS 521 Most monitor functions can be selected (or 522 de-selected) by adjusting the definition of 523 CONFIG_COMMANDS; to select individual functions, 524 #define CONFIG_COMMANDS by "OR"ing any of the 525 following values: 526 527 #define enables commands: 528 ------------------------- 529 CFG_CMD_ASKENV * ask for env variable 530 CFG_CMD_BDI bdinfo 531 CFG_CMD_BEDBUG Include BedBug Debugger 532 CFG_CMD_BOOTD bootd 533 CFG_CMD_CACHE icache, dcache 534 CFG_CMD_CONSOLE coninfo 535 CFG_CMD_DATE * support for RTC, date/time... 536 CFG_CMD_DHCP DHCP support 537 CFG_CMD_ECHO * echo arguments 538 CFG_CMD_EEPROM * EEPROM read/write support 539 CFG_CMD_ELF bootelf, bootvx 540 CFG_CMD_ENV saveenv 541 CFG_CMD_FDC * Floppy Disk Support 542 CFG_CMD_FDOS * Dos diskette Support 543 CFG_CMD_FLASH flinfo, erase, protect 544 CFG_CMD_FPGA FPGA device initialization support 545 CFG_CMD_I2C * I2C serial bus support 546 CFG_CMD_IDE * IDE harddisk support 547 CFG_CMD_IMI iminfo 548 CFG_CMD_IMMAP * IMMR dump support 549 CFG_CMD_IRQ * irqinfo 550 CFG_CMD_KGDB * kgdb 551 CFG_CMD_LOADB loadb 552 CFG_CMD_LOADS loads 553 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 554 loop, mtest 555 CFG_CMD_MII MII utility commands 556 CFG_CMD_NET bootp, tftpboot, rarpboot 557 CFG_CMD_PCI * pciinfo 558 CFG_CMD_PCMCIA * PCMCIA support 559 CFG_CMD_REGINFO * Register dump 560 CFG_CMD_RUN run command in env variable 561 CFG_CMD_SCSI * SCSI Support 562 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 563 CFG_CMD_SPI * SPI serial bus support 564 CFG_CMD_USB * USB support 565 CFG_CMD_BSP * Board SPecific functions 566 ----------------------------------------------- 567 CFG_CMD_ALL all 568 569 CFG_CMD_DFL Default configuration; at the moment 570 this is includes all commands, except 571 the ones marked with "*" in the list 572 above. 573 574 If you don't define CONFIG_COMMANDS it defaults to 575 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 576 override the default settings in the respective 577 include file. 578 579 EXAMPLE: If you want all functions except of network 580 support you can write: 581 582 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 583 584 585 Note: Don't enable the "icache" and "dcache" commands 586 (configuration option CFG_CMD_CACHE) unless you know 587 what you (and your U-Boot users) are doing. Data 588 cache cannot be enabled on systems like the 8xx or 589 8260 (where accesses to the IMMR region must be 590 uncached), and it cannot be disabled on all other 591 systems where we (mis-) use the data cache to hold an 592 initial stack and some data. 593 594 595 XXX - this list needs to get updated! 596 597- Watchdog: 598 CONFIG_WATCHDOG 599 If this variable is defined, it enables watchdog 600 support. There must support in the platform specific 601 code for a watchdog. For the 8xx and 8260 CPUs, the 602 SIU Watchdog feature is enabled in the SYPCR 603 register. 604 605- Real-Time Clock: 606 607 When CFG_CMD_DATE is selected, the type of the RTC 608 has to be selected, too. Define exactly one of the 609 following options: 610 611 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 612 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 613 CONFIG_RTC_MC146818 - use MC146818 RTC 614 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 615 616- Timestamp Support: 617 618 When CONFIG_TIMESTAMP is selected, the timestamp 619 (date and time) of an image is printed by image 620 commands like bootm or iminfo. This option is 621 automatically enabled when you select CFG_CMD_DATE . 622 623- Partition Support: 624 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 625 and/or CONFIG_ISO_PARTITION 626 627 If IDE or SCSI support is enabled (CFG_CMD_IDE or 628 CFG_CMD_SCSI) you must configure support for at least 629 one partition type as well. 630 631- IDE Reset method: 632 CONFIG_IDE_RESET_ROUTINE 633 634 Set this to define that instead of a reset Pin, the 635 routine ide_set_reset(int idereset) will be used. 636 637- ATAPI Support: 638 CONFIG_ATAPI 639 640 Set this to enable ATAPI support. 641 642- SCSI Support: 643 At the moment only there is only support for the 644 SYM53C8XX SCSI controller; define 645 CONFIG_SCSI_SYM53C8XX to enable it. 646 647 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 648 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 649 CFG_SCSI_MAX_LUN] can be adjusted to define the 650 maximum numbers of LUNs, SCSI ID's and target 651 devices. 652 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 653 654- NETWORK Support (PCI): 655 CONFIG_EEPRO100 656 Support for Intel 82557/82559/82559ER chips. 657 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 658 write routine for first time initialisation. 659 660 CONFIG_TULIP 661 Support for Digital 2114x chips. 662 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 663 modem chip initialisation (KS8761/QS6611). 664 665 CONFIG_NATSEMI 666 Support for National dp83815 chips. 667 668 CONFIG_NS8382X 669 Support for National dp8382[01] gigabit chips. 670 671- USB Support: 672 At the moment only the UHCI host controller is 673 supported (PIP405, MIP405); define 674 CONFIG_USB_UHCI to enable it. 675 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 676 end define CONFIG_USB_STORAGE to enable the USB 677 storage devices. 678 Note: 679 Supported are USB Keyboards and USB Floppy drives 680 (TEAC FD-05PUB). 681 682- Keyboard Support: 683 CONFIG_ISA_KEYBOARD 684 685 Define this to enable standard (PC-Style) keyboard 686 support 687 688 CONFIG_I8042_KBD 689 Standard PC keyboard driver with US (is default) and 690 GERMAN key layout (switch via environment 'keymap=de') support. 691 Export function i8042_kbd_init, i8042_tstc and i8042_getc 692 for cfb_console. Supports cursor blinking. 693 694- Video support: 695 CONFIG_VIDEO 696 697 Define this to enable video support (for output to 698 video). 699 700 CONFIG_VIDEO_CT69000 701 702 Enable Chips & Technologies 69000 Video chip 703 704 CONFIG_VIDEO_SMI_LYNXEM 705 Enable Silicon Motion SMI 712/710/810 Video chip 706 Videomode are selected via environment 'videomode' with 707 standard LiLo mode numbers. 708 Following modes are supported (* is default): 709 710 800x600 1024x768 1280x1024 711 256 (8bit) 303* 305 307 712 65536 (16bit) 314 317 31a 713 16,7 Mill (24bit) 315 318 31b 714 (i.e. setenv videomode 317; saveenv; reset;) 715 716 CONFIG_VIDEO_SED13806 717 Enable Epson SED13806 driver. This driver supports 8bpp 718 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 719 or CONFIG_VIDEO_SED13806_16BPP 720 721 722- LCD Support: CONFIG_LCD 723 724 Define this to enable LCD support (for output to LCD 725 display); also select one of the supported displays 726 by defining one of these: 727 728 CONFIG_NEC_NL6648AC33: 729 730 NEC NL6648AC33-18. Active, color, single scan. 731 732 CONFIG_NEC_NL6648BC20 733 734 NEC NL6648BC20-08. 6.5", 640x480. 735 Active, color, single scan. 736 737 CONFIG_SHARP_16x9 738 739 Sharp 320x240. Active, color, single scan. 740 It isn't 16x9, and I am not sure what it is. 741 742 CONFIG_SHARP_LQ64D341 743 744 Sharp LQ64D341 display, 640x480. 745 Active, color, single scan. 746 747 CONFIG_HLD1045 748 749 HLD1045 display, 640x480. 750 Active, color, single scan. 751 752 CONFIG_OPTREX_BW 753 754 Optrex CBL50840-2 NF-FW 99 22 M5 755 or 756 Hitachi LMG6912RPFC-00T 757 or 758 Hitachi SP14Q002 759 760 320x240. Black & white. 761 762 Normally display is black on white background; define 763 CFG_WHITE_ON_BLACK to get it inverted. 764 765- Ethernet address: 766 CONFIG_ETHADDR 767 CONFIG_ETH2ADDR 768 CONFIG_ETH3ADDR 769 770 Define a default value for ethernet address to use 771 for the respective ethernet interface, in case this 772 is not determined automatically. 773 774- IP address: 775 CONFIG_IPADDR 776 777 Define a default value for the IP address to use for 778 the default ethernet interface, in case this is not 779 determined through e.g. bootp. 780 781- Server IP address: 782 CONFIG_SERVERIP 783 784 Defines a default value for theIP address of a TFTP 785 server to contact when using the "tftboot" command. 786 787- BOOTP Recovery Mode: 788 CONFIG_BOOTP_RANDOM_DELAY 789 790 If you have many targets in a network that try to 791 boot using BOOTP, you may want to avoid that all 792 systems send out BOOTP requests at precisely the same 793 moment (which would happen for instance at recovery 794 from a power failure, when all systems will try to 795 boot, thus flooding the BOOTP server. Defining 796 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 797 inserted before sending out BOOTP requests. The 798 following delays are insterted then: 799 800 1st BOOTP request: delay 0 ... 1 sec 801 2nd BOOTP request: delay 0 ... 2 sec 802 3rd BOOTP request: delay 0 ... 4 sec 803 4th and following 804 BOOTP requests: delay 0 ... 8 sec 805 806- Status LED: CONFIG_STATUS_LED 807 808 Several configurations allow to display the current 809 status using a LED. For instance, the LED will blink 810 fast while running U-Boot code, stop blinking as 811 soon as a reply to a BOOTP request was received, and 812 start blinking slow once the Linux kernel is running 813 (supported by a status LED driver in the Linux 814 kernel). Defining CONFIG_STATUS_LED enables this 815 feature in U-Boot. 816 817- CAN Support: CONFIG_CAN_DRIVER 818 819 Defining CONFIG_CAN_DRIVER enables CAN driver support 820 on those systems that support this (optional) 821 feature, like the TQM8xxL modules. 822 823- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 824 825 Enables I2C serial bus commands. If this is selected, 826 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 827 to include the appropriate I2C driver. 828 829 See also: common/cmd_i2c.c for a description of the 830 command line interface. 831 832 833 CONFIG_HARD_I2C 834 835 Selects the CPM hardware driver for I2C. 836 837 CONFIG_SOFT_I2C 838 839 Use software (aka bit-banging) driver instead of CPM 840 or similar hardware support for I2C. This is configured 841 via the following defines. 842 843 I2C_INIT 844 845 (Optional). Any commands necessary to enable I2C 846 controller or configure ports. 847 848 I2C_PORT 849 850 (Only for MPC8260 CPU). The I/O port to use (the code 851 assumes both bits are on the same port). Valid values 852 are 0..3 for ports A..D. 853 854 I2C_ACTIVE 855 856 The code necessary to make the I2C data line active 857 (driven). If the data line is open collector, this 858 define can be null. 859 860 I2C_TRISTATE 861 862 The code necessary to make the I2C data line tri-stated 863 (inactive). If the data line is open collector, this 864 define can be null. 865 866 I2C_READ 867 868 Code that returns TRUE if the I2C data line is high, 869 FALSE if it is low. 870 871 I2C_SDA(bit) 872 873 If <bit> is TRUE, sets the I2C data line high. If it 874 is FALSE, it clears it (low). 875 876 I2C_SCL(bit) 877 878 If <bit> is TRUE, sets the I2C clock line high. If it 879 is FALSE, it clears it (low). 880 881 I2C_DELAY 882 883 This delay is invoked four times per clock cycle so this 884 controls the rate of data transfer. The data rate thus 885 is 1 / (I2C_DELAY * 4). 886 887- SPI Support: CONFIG_SPI 888 889 Enables SPI driver (so far only tested with 890 SPI EEPROM, also an instance works with Crystal A/D and 891 D/As on the SACSng board) 892 893 CONFIG_SPI_X 894 895 Enables extended (16-bit) SPI EEPROM addressing. 896 (symmetrical to CONFIG_I2C_X) 897 898 CONFIG_SOFT_SPI 899 900 Enables a software (bit-bang) SPI driver rather than 901 using hardware support. This is a general purpose 902 driver that only requires three general I/O port pins 903 (two outputs, one input) to function. If this is 904 defined, the board configuration must define several 905 SPI configuration items (port pins to use, etc). For 906 an example, see include/configs/sacsng.h. 907 908- FPGA Support: CONFIG_FPGA_COUNT 909 910 Specify the number of FPGA devices to support. 911 912 CONFIG_FPGA 913 914 Used to specify the types of FPGA devices. For 915 example, 916 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 917 918 CFG_FPGA_PROG_FEEDBACK 919 920 Enable printing of hash marks during FPGA 921 configuration. 922 923 CFG_FPGA_CHECK_BUSY 924 925 Enable checks on FPGA configuration interface busy 926 status by the configuration function. This option 927 will require a board or device specific function to 928 be written. 929 930 CONFIG_FPGA_DELAY 931 932 If defined, a function that provides delays in the 933 FPGA configuration driver. 934 935 CFG_FPGA_CHECK_CTRLC 936 937 Allow Control-C to interrupt FPGA configuration 938 939 CFG_FPGA_CHECK_ERROR 940 941 Check for configuration errors during FPGA bitfile 942 loading. For example, abort during Virtex II 943 configuration if the INIT_B line goes low (which 944 indicated a CRC error). 945 946 CFG_FPGA_WAIT_INIT 947 948 Maximum time to wait for the INIT_B line to deassert 949 after PROB_B has been deasserted during a Virtex II 950 FPGA configuration sequence. The default time is 500 mS. 951 952 CFG_FPGA_WAIT_BUSY 953 954 Maximum time to wait for BUSY to deassert during 955 Virtex II FPGA configuration. The default is 5 mS. 956 957 CFG_FPGA_WAIT_CONFIG 958 959 Time to wait after FPGA configuration. The default is 960 200 mS. 961 962- FPGA Support: CONFIG_FPGA_COUNT 963 964 Specify the number of FPGA devices to support. 965 966 CONFIG_FPGA 967 968 Used to specify the types of FPGA devices. For example, 969 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 970 971 CFG_FPGA_PROG_FEEDBACK 972 973 Enable printing of hash marks during FPGA configuration. 974 975 CFG_FPGA_CHECK_BUSY 976 977 Enable checks on FPGA configuration interface busy 978 status by the configuration function. This option 979 will require a board or device specific function to 980 be written. 981 982 CONFIG_FPGA_DELAY 983 984 If defined, a function that provides delays in the FPGA 985 configuration driver. 986 987 CFG_FPGA_CHECK_CTRLC 988 Allow Control-C to interrupt FPGA configuration 989 990 CFG_FPGA_CHECK_ERROR 991 992 Check for configuration errors during FPGA bitfile 993 loading. For example, abort during Virtex II 994 configuration if the INIT_B line goes low (which 995 indicated a CRC error). 996 997 CFG_FPGA_WAIT_INIT 998 999 Maximum time to wait for the INIT_B line to deassert 1000 after PROB_B has been deasserted during a Virtex II 1001 FPGA configuration sequence. The default time is 500 1002 mS. 1003 1004 CFG_FPGA_WAIT_BUSY 1005 1006 Maximum time to wait for BUSY to deassert during 1007 Virtex II FPGA configuration. The default is 5 mS. 1008 1009 CFG_FPGA_WAIT_CONFIG 1010 1011 Time to wait after FPGA configuration. The default is 1012 200 mS. 1013 1014- Configuration Management: 1015 CONFIG_IDENT_STRING 1016 1017 If defined, this string will be added to the U-Boot 1018 version information (U_BOOT_VERSION) 1019 1020- Vendor Parameter Protection: 1021 1022 U-Boot considers the values of the environment 1023 variables "serial#" (Board Serial Number) and 1024 "ethaddr" (Ethernet Address) to bb parameters that 1025 are set once by the board vendor / manufacturer, and 1026 protects these variables from casual modification by 1027 the user. Once set, these variables are read-only, 1028 and write or delete attempts are rejected. You can 1029 change this behviour: 1030 1031 If CONFIG_ENV_OVERWRITE is #defined in your config 1032 file, the write protection for vendor parameters is 1033 completely disabled. Anybody can change or delte 1034 these parameters. 1035 1036 Alternatively, if you #define _both_ CONFIG_ETHADDR 1037 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1038 ethernet address is installed in the environment, 1039 which can be changed exactly ONCE by the user. [The 1040 serial# is unaffected by this, i. e. it remains 1041 read-only.] 1042 1043- Protected RAM: 1044 CONFIG_PRAM 1045 1046 Define this variable to enable the reservation of 1047 "protected RAM", i. e. RAM which is not overwritten 1048 by U-Boot. Define CONFIG_PRAM to hold the number of 1049 kB you want to reserve for pRAM. You can overwrite 1050 this default value by defining an environment 1051 variable "pram" to the number of kB you want to 1052 reserve. Note that the board info structure will 1053 still show the full amount of RAM. If pRAM is 1054 reserved, a new environment variable "mem" will 1055 automatically be defined to hold the amount of 1056 remaining RAM in a form that can be passed as boot 1057 argument to Linux, for instance like that: 1058 1059 setenv bootargs ... mem=\$(mem) 1060 saveenv 1061 1062 This way you can tell Linux not to use this memory, 1063 either, which results in a memory region that will 1064 not be affected by reboots. 1065 1066 *WARNING* If your board configuration uses automatic 1067 detection of the RAM size, you must make sure that 1068 this memory test is non-destructive. So far, the 1069 following board configurations are known to be 1070 "pRAM-clean": 1071 1072 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1073 HERMES, IP860, RPXlite, LWMON, LANTEC, 1074 PCU_E, FLAGADM, TQM8260 1075 1076- Error Recovery: 1077 CONFIG_PANIC_HANG 1078 1079 Define this variable to stop the system in case of a 1080 fatal error, so that you have to reset it manually. 1081 This is probably NOT a good idea for an embedded 1082 system where you want to system to reboot 1083 automatically as fast as possible, but it may be 1084 useful during development since you can try to debug 1085 the conditions that lead to the situation. 1086 1087 CONFIG_NET_RETRY_COUNT 1088 1089 This variable defines the number of retries for 1090 network operations like ARP, RARP, TFTP, or BOOTP 1091 before giving up the operation. If not defined, a 1092 default value of 5 is used. 1093 1094- Command Interpreter: 1095 CFG_HUSH_PARSER 1096 1097 Define this variable to enable the "hush" shell (from 1098 Busybox) as command line interpreter, thus enabling 1099 powerful command line syntax like 1100 if...then...else...fi conditionals or `&&' and '||' 1101 constructs ("shell scripts"). 1102 1103 If undefined, you get the old, much simpler behaviour 1104 with a somewhat smaller memory footprint. 1105 1106 1107 CFG_PROMPT_HUSH_PS2 1108 1109 This defines the secondary prompt string, which is 1110 printed when the command interpreter needs more input 1111 to complete a command. Usually "> ". 1112 1113 Note: 1114 1115 In the current implementation, the local variables 1116 space and global environment variables space are 1117 separated. Local variables are those you define by 1118 simply typing like `name=value'. To access a local 1119 variable later on, you have write `$name' or 1120 `${name}'; variable directly by typing say `$name' at 1121 the command prompt. 1122 1123 Global environment variables are those you use 1124 setenv/printenv to work with. To run a command stored 1125 in such a variable, you need to use the run command, 1126 and you must not use the '$' sign to access them. 1127 1128 To store commands and special characters in a 1129 variable, please use double quotation marks 1130 surrounding the whole text of the variable, instead 1131 of the backslashes before semicolons and special 1132 symbols. 1133 1134- Default Environment 1135 CONFIG_EXTRA_ENV_SETTINGS 1136 1137 Define this to contain any number of null terminated 1138 strings (variable = value pairs) that will be part of 1139 the default enviroment compiled into the boot image. 1140 1141 For example, place something like this in your 1142 board's config file: 1143 1144 #define CONFIG_EXTRA_ENV_SETTINGS \ 1145 "myvar1=value1\0" \ 1146 "myvar2=value2\0" 1147 1148 Warning: This method is based on knowledge about the 1149 internal format how the environment is stored by the 1150 U-Boot code. This is NOT an official, exported 1151 interface! Although it is unlikely that this format 1152 will change soon, but there is no guarantee either. 1153 You better know what you are doing here. 1154 1155 Note: overly (ab)use of the default environment is 1156 discouraged. Make sure to check other ways to preset 1157 the environment like the autoscript function or the 1158 boot command first. 1159 1160- Show boot progress 1161 CONFIG_SHOW_BOOT_PROGRESS 1162 1163 Defining this option allows to add some board- 1164 specific code (calling a user-provided function 1165 "show_boot_progress(int)") that enables you to show 1166 the system's boot progress on some display (for 1167 example, some LED's) on your board. At the moment, 1168 the following checkpoints are implemented: 1169 1170 Arg Where When 1171 1 common/cmd_bootm.c before attempting to boot an image 1172 -1 common/cmd_bootm.c Image header has bad magic number 1173 2 common/cmd_bootm.c Image header has correct magic number 1174 -2 common/cmd_bootm.c Image header has bad checksum 1175 3 common/cmd_bootm.c Image header has correct checksum 1176 -3 common/cmd_bootm.c Image data has bad checksum 1177 4 common/cmd_bootm.c Image data has correct checksum 1178 -4 common/cmd_bootm.c Image is for unsupported architecture 1179 5 common/cmd_bootm.c Architecture check OK 1180 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1181 6 common/cmd_bootm.c Image Type check OK 1182 -6 common/cmd_bootm.c gunzip uncompression error 1183 -7 common/cmd_bootm.c Unimplemented compression type 1184 7 common/cmd_bootm.c Uncompression OK 1185 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1186 8 common/cmd_bootm.c Image Type check OK 1187 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1188 9 common/cmd_bootm.c Start initial ramdisk verification 1189 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1190 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1191 10 common/cmd_bootm.c Ramdisk header is OK 1192 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1193 11 common/cmd_bootm.c Ramdisk data has correct checksum 1194 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1195 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1196 13 common/cmd_bootm.c Start multifile image verification 1197 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1198 15 common/cmd_bootm.c All preparation done, transferring control to OS 1199 1200 -1 common/cmd_doc.c Bad usage of "doc" command 1201 -1 common/cmd_doc.c No boot device 1202 -1 common/cmd_doc.c Unknown Chip ID on boot device 1203 -1 common/cmd_doc.c Read Error on boot device 1204 -1 common/cmd_doc.c Image header has bad magic number 1205 1206 -1 common/cmd_ide.c Bad usage of "ide" command 1207 -1 common/cmd_ide.c No boot device 1208 -1 common/cmd_ide.c Unknown boot device 1209 -1 common/cmd_ide.c Unknown partition table 1210 -1 common/cmd_ide.c Invalid partition type 1211 -1 common/cmd_ide.c Read Error on boot device 1212 -1 common/cmd_ide.c Image header has bad magic number 1213 1214 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1215 1216 1217Modem Support: 1218-------------- 1219 1220[so far only for SMDK2400 board] 1221 1222- Modem support endable: 1223 CONFIG_MODEM_SUPPORT 1224 1225- RTS/CTS Flow control enable: 1226 CONFIG_HWFLOW 1227 1228- Modem debug support: 1229 CONFIG_MODEM_SUPPORT_DEBUG 1230 1231 Enables debugging stuff (char screen[1024], dbg()) 1232 for modem support. Useful only with BDI2000. 1233 1234- General: 1235 1236 In the target system modem support is enabled when a 1237 specific key (key combination) is pressed during 1238 power-on. Otherwise U-Boot will boot normally 1239 (autoboot). The key_pressed() fuction is called from 1240 board_init(). Currently key_pressed() is a dummy 1241 function, returning 1 and thus enabling modem 1242 initialization. 1243 1244 If there are no modem init strings in the 1245 environment, U-Boot proceed to autoboot; the 1246 previous output (banner, info printfs) will be 1247 supressed, though. 1248 1249 See also: doc/README.Modem 1250 1251 1252 1253 1254Configuration Settings: 1255----------------------- 1256 1257- CFG_LONGHELP: Defined when you want long help messages included; 1258 undefine this when you're short of memory. 1259 1260- CFG_PROMPT: This is what U-Boot prints on the console to 1261 prompt for user input. 1262 1263- CFG_CBSIZE: Buffer size for input from the Console 1264 1265- CFG_PBSIZE: Buffer size for Console output 1266 1267- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1268 1269- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1270 the application (usually a Linux kernel) when it is 1271 booted 1272 1273- CFG_BAUDRATE_TABLE: 1274 List of legal baudrate settings for this board. 1275 1276- CFG_CONSOLE_INFO_QUIET 1277 Suppress display of console information at boot. 1278 1279- CFG_CONSOLE_IS_IN_ENV 1280 If the board specific function 1281 extern int overwrite_console (void); 1282 returns 1, the stdin, stderr and stdout are switched to the 1283 serial port, else the settings in the environment are used. 1284 1285- CFG_CONSOLE_OVERWRITE_ROUTINE 1286 Enable the call to overwrite_console(). 1287 1288- CFG_CONSOLE_ENV_OVERWRITE 1289 Enable overwrite of previous console environment settings. 1290 1291- CFG_MEMTEST_START, CFG_MEMTEST_END: 1292 Begin and End addresses of the area used by the 1293 simple memory test. 1294 1295- CFG_ALT_MEMTEST: 1296 Enable an alternate, more extensive memory test. 1297 1298- CFG_TFTP_LOADADDR: 1299 Default load address for network file downloads 1300 1301- CFG_LOADS_BAUD_CHANGE: 1302 Enable temporary baudrate change while serial download 1303 1304- CFG_SDRAM_BASE: 1305 Physical start address of SDRAM. _Must_ be 0 here. 1306 1307- CFG_MBIO_BASE: 1308 Physical start address of Motherboard I/O (if using a 1309 Cogent motherboard) 1310 1311- CFG_FLASH_BASE: 1312 Physical start address of Flash memory. 1313 1314- CFG_MONITOR_BASE: 1315 Physical start address of boot monitor code (set by 1316 make config files to be same as the text base address 1317 (TEXT_BASE) used when linking) - same as 1318 CFG_FLASH_BASE when booting from flash. 1319 1320- CFG_MONITOR_LEN: 1321 Size of memory reserved for monitor code 1322 1323- CFG_MALLOC_LEN: 1324 Size of DRAM reserved for malloc() use. 1325 1326- CFG_BOOTMAPSZ: 1327 Maximum size of memory mapped by the startup code of 1328 the Linux kernel; all data that must be processed by 1329 the Linux kernel (bd_info, boot arguments, eventually 1330 initrd image) must be put below this limit. 1331 1332- CFG_MAX_FLASH_BANKS: 1333 Max number of Flash memory banks 1334 1335- CFG_MAX_FLASH_SECT: 1336 Max number of sectors on a Flash chip 1337 1338- CFG_FLASH_ERASE_TOUT: 1339 Timeout for Flash erase operations (in ms) 1340 1341- CFG_FLASH_WRITE_TOUT: 1342 Timeout for Flash write operations (in ms) 1343 1344- CFG_DIRECT_FLASH_TFTP: 1345 1346 Enable TFTP transfers directly to flash memory; 1347 without this option such a download has to be 1348 performed in two steps: (1) download to RAM, and (2) 1349 copy from RAM to flash. 1350 1351 The two-step approach is usually more reliable, since 1352 you can check if the download worked before you erase 1353 the flash, but in some situations (when sytem RAM is 1354 too limited to allow for a tempory copy of the 1355 downloaded image) this option may be very useful. 1356 1357- CFG_FLASH_CFI: 1358 Define if the flash driver uses extra elements in the 1359 common flash structure for storing flash geometry 1360 1361The following definitions that deal with the placement and management 1362of environment data (variable area); in general, we support the 1363following configurations: 1364 1365- CFG_ENV_IS_IN_FLASH: 1366 1367 Define this if the environment is in flash memory. 1368 1369 a) The environment occupies one whole flash sector, which is 1370 "embedded" in the text segment with the U-Boot code. This 1371 happens usually with "bottom boot sector" or "top boot 1372 sector" type flash chips, which have several smaller 1373 sectors at the start or the end. For instance, such a 1374 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1375 such a case you would place the environment in one of the 1376 4 kB sectors - with U-Boot code before and after it. With 1377 "top boot sector" type flash chips, you would put the 1378 environment in one of the last sectors, leaving a gap 1379 between U-Boot and the environment. 1380 1381 - CFG_ENV_OFFSET: 1382 1383 Offset of environment data (variable area) to the 1384 beginning of flash memory; for instance, with bottom boot 1385 type flash chips the second sector can be used: the offset 1386 for this sector is given here. 1387 1388 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1389 1390 - CFG_ENV_ADDR: 1391 1392 This is just another way to specify the start address of 1393 the flash sector containing the environment (instead of 1394 CFG_ENV_OFFSET). 1395 1396 - CFG_ENV_SECT_SIZE: 1397 1398 Size of the sector containing the environment. 1399 1400 1401 b) Sometimes flash chips have few, equal sized, BIG sectors. 1402 In such a case you don't want to spend a whole sector for 1403 the environment. 1404 1405 - CFG_ENV_SIZE: 1406 1407 If you use this in combination with CFG_ENV_IS_IN_FLASH 1408 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1409 of this flash sector for the environment. This saves 1410 memory for the RAM copy of the environment. 1411 1412 It may also save flash memory if you decide to use this 1413 when your environment is "embedded" within U-Boot code, 1414 since then the remainder of the flash sector could be used 1415 for U-Boot code. It should be pointed out that this is 1416 STRONGLY DISCOURAGED from a robustness point of view: 1417 updating the environment in flash makes it always 1418 necessary to erase the WHOLE sector. If something goes 1419 wrong before the contents has been restored from a copy in 1420 RAM, your target system will be dead. 1421 1422 - CFG_ENV_ADDR_REDUND 1423 CFG_ENV_SIZE_REDUND 1424 1425 These settings describe a second storage area used to hold 1426 a redundand copy of the environment data, so that there is 1427 a valid backup copy in case there is a power failur during 1428 a "saveenv" operation. 1429 1430BE CAREFUL! Any changes to the flash layout, and some changes to the 1431source code will make it necessary to adapt <board>/u-boot.lds* 1432accordingly! 1433 1434 1435- CFG_ENV_IS_IN_NVRAM: 1436 1437 Define this if you have some non-volatile memory device 1438 (NVRAM, battery buffered SRAM) which you want to use for the 1439 environment. 1440 1441 - CFG_ENV_ADDR: 1442 - CFG_ENV_SIZE: 1443 1444 These two #defines are used to determin the memory area you 1445 want to use for environment. It is assumed that this memory 1446 can just be read and written to, without any special 1447 provision. 1448 1449BE CAREFUL! The first access to the environment happens quite early 1450in U-Boot initalization (when we try to get the setting of for the 1451console baudrate). You *MUST* have mappend your NVRAM area then, or 1452U-Boot will hang. 1453 1454Please note that even with NVRAM we still use a copy of the 1455environment in RAM: we could work on NVRAM directly, but we want to 1456keep settings there always unmodified except somebody uses "saveenv" 1457to save the current settings. 1458 1459 1460- CFG_ENV_IS_IN_EEPROM: 1461 1462 Use this if you have an EEPROM or similar serial access 1463 device and a driver for it. 1464 1465 - CFG_ENV_OFFSET: 1466 - CFG_ENV_SIZE: 1467 1468 These two #defines specify the offset and size of the 1469 environment area within the total memory of your EEPROM. 1470 1471 - CFG_I2C_EEPROM_ADDR: 1472 If defined, specified the chip address of the EEPROM device. 1473 The default address is zero. 1474 1475 - CFG_EEPROM_PAGE_WRITE_BITS: 1476 If defined, the number of bits used to address bytes in a 1477 single page in the EEPROM device. A 64 byte page, for example 1478 would require six bits. 1479 1480 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1481 If defined, the number of milliseconds to delay between 1482 page writes. The default is zero milliseconds. 1483 1484 - CFG_I2C_EEPROM_ADDR_LEN: 1485 The length in bytes of the EEPROM memory array address. Note 1486 that this is NOT the chip address length! 1487 1488 - CFG_EEPROM_SIZE: 1489 The size in bytes of the EEPROM device. 1490 1491 - CFG_I2C_EEPROM_ADDR: 1492 If defined, specified the chip address of the EEPROM device. 1493 The default address is zero. 1494 1495 - CFG_EEPROM_PAGE_WRITE_BITS: 1496 If defined, the number of bits used to address bytes in a 1497 single page in the EEPROM device. A 64 byte page, for example 1498 would require six bits. 1499 1500 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1501 If defined, the number of milliseconds to delay between 1502 page writes. The default is zero milliseconds. 1503 1504 - CFG_I2C_EEPROM_ADDR_LEN: 1505 The length in bytes of the EEPROM memory array address. Note 1506 that this is NOT the chip address length! 1507 1508 - CFG_EEPROM_SIZE: 1509 The size in bytes of the EEPROM device. 1510 1511- CFG_SPI_INIT_OFFSET 1512 1513 Defines offset to the initial SPI buffer area in DPRAM. The 1514 area is used at an early stage (ROM part) if the environment 1515 is configured to reside in the SPI EEPROM: We need a 520 byte 1516 scratch DPRAM area. It is used between the two initialization 1517 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1518 to be a good choice since it makes it far enough from the 1519 start of the data area as well as from the stack pointer. 1520 1521Please note that the environment is read-only as long as the monitor 1522has been relocated to RAM and a RAM copy of the environment has been 1523created; also, when using EEPROM you will have to use getenv_r() 1524until then to read environment variables. 1525 1526The environment is now protected by a CRC32 checksum. Before the 1527monitor is relocated into RAM, as a result of a bad CRC you will be 1528working with the compiled-in default environment - *silently*!!! 1529[This is necessary, because the first environment variable we need is 1530the "baudrate" setting for the console - if we have a bad CRC, we 1531don't have any device yet where we could complain.] 1532 1533Note: once the monitor has been relocated, then it will complain if 1534the default environment is used; a new CRC is computed as soon as you 1535use the "setenv" command to modify / delete / add any environment 1536variable [even when you try to delete a non-existing variable!]. 1537 1538Note2: you must edit your u-boot.lds file to reflect this 1539configuration. 1540 1541 1542Low Level (hardware related) configuration options: 1543 1544- CFG_CACHELINE_SIZE: 1545 Cache Line Size of the CPU. 1546 1547- CFG_DEFAULT_IMMR: 1548 Default address of the IMMR after system reset. 1549 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1550 to be able to adjust the position of the IMMR 1551 register after a reset. 1552 1553- Floppy Disk Support: 1554 CFG_FDC_DRIVE_NUMBER 1555 1556 the default drive number (default value 0) 1557 1558 CFG_ISA_IO_STRIDE 1559 1560 defines the spacing between fdc chipset registers 1561 (default value 1) 1562 1563 CFG_ISA_IO_OFFSET 1564 1565 defines the offset of register from address. It 1566 depends on which part of the data bus is connected to 1567 the fdc chipset. (default value 0) 1568 1569 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1570 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1571 default value. 1572 1573 if CFG_FDC_HW_INIT is defined, then the function 1574 fdc_hw_init() is called at the beginning of the FDC 1575 setup. fdc_hw_init() must be provided by the board 1576 source code. It is used to make hardware dependant 1577 initializations. 1578 1579- CFG_IMMR: Physical address of the Internal Memory Mapped 1580 Register; DO NOT CHANGE! (11-4) 1581 [MPC8xx systems only] 1582 1583- CFG_INIT_RAM_ADDR: 1584 1585 Start address of memory area tha can be used for 1586 initial data and stack; please note that this must be 1587 writable memory that is working WITHOUT special 1588 initialization, i. e. you CANNOT use normal RAM which 1589 will become available only after programming the 1590 memory controller and running certain initialization 1591 sequences. 1592 1593 U-Boot uses the following memory types: 1594 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1595 - MPC824X: data cache 1596 - PPC4xx: data cache 1597 1598- CFG_INIT_DATA_OFFSET: 1599 1600 Offset of the initial data structure in the memory 1601 area defined by CFG_INIT_RAM_ADDR. Usually 1602 CFG_INIT_DATA_OFFSET is chosen such that the initial 1603 data is located at the end of the available space 1604 (sometimes written as (CFG_INIT_RAM_END - 1605 CFG_INIT_DATA_SIZE), and the initial stack is just 1606 below that area (growing from (CFG_INIT_RAM_ADDR + 1607 CFG_INIT_DATA_OFFSET) downward. 1608 1609 Note: 1610 On the MPC824X (or other systems that use the data 1611 cache for initial memory) the address chosen for 1612 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1613 point to an otherwise UNUSED address space between 1614 the top of RAM and the start of the PCI space. 1615 1616- CFG_SIUMCR: SIU Module Configuration (11-6) 1617 1618- CFG_SYPCR: System Protection Control (11-9) 1619 1620- CFG_TBSCR: Time Base Status and Control (11-26) 1621 1622- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1623 1624- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1625 1626- CFG_SCCR: System Clock and reset Control Register (15-27) 1627 1628- CFG_OR_TIMING_SDRAM: 1629 SDRAM timing 1630 1631- CFG_MAMR_PTA: 1632 periodic timer for refresh 1633 1634- CFG_DER: Debug Event Register (37-47) 1635 1636- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1637 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1638 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1639 CFG_BR1_PRELIM: 1640 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1641 1642- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1643 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1644 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1645 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1646 1647- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1648 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1649 Machine Mode Register and Memory Periodic Timer 1650 Prescaler definitions (SDRAM timing) 1651 1652- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1653 enable I2C microcode relocation patch (MPC8xx); 1654 define relocation offset in DPRAM [DSP2] 1655 1656- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1657 enable SPI microcode relocation patch (MPC8xx); 1658 define relocation offset in DPRAM [SCC4] 1659 1660- CFG_USE_OSCCLK: 1661 Use OSCM clock mode on MBX8xx board. Be careful, 1662 wrong setting might damage your board. Read 1663 doc/README.MBX before setting this variable! 1664 1665- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1666 Offset of the bootmode word in DPRAM used by post 1667 (Power On Self Tests). This definition overrides 1668 #define'd default value in commproc.h resp. 1669 cpm_8260.h. 1670 1671Building the Software: 1672====================== 1673 1674Building U-Boot has been tested in native PPC environments (on a 1675PowerBook G3 running LinuxPPC 2000) and in cross environments 1676(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1677NetBSD 1.5 on x86). 1678 1679If you are not using a native PPC environment, it is assumed that you 1680have the GNU cross compiling tools available in your path and named 1681with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1682you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1683the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1684change it to: 1685 1686 CROSS_COMPILE = ppc_4xx- 1687 1688 1689U-Boot is intended to be simple to build. After installing the 1690sources you must configure U-Boot for one specific board type. This 1691is done by typing: 1692 1693 make NAME_config 1694 1695where "NAME_config" is the name of one of the existing 1696configurations; the following names are supported: 1697 1698 ADCIOP_config GTH_config TQM850L_config 1699 ADS860_config IP860_config TQM855L_config 1700 AR405_config IVML24_config TQM860L_config 1701 CANBT_config IVMS8_config WALNUT405_config 1702 CPCI405_config LANTEC_config cogent_common_config 1703 CPCIISER4_config MBX_config cogent_mpc8260_config 1704 CU824_config MBX860T_config cogent_mpc8xx_config 1705 ESTEEM192E_config RPXlite_config hermes_config 1706 ETX094_config RPXsuper_config hymod_config 1707 FADS823_config SM850_config lwmon_config 1708 FADS850SAR_config SPD823TS_config pcu_e_config 1709 FADS860T_config SXNI855T_config rsdproto_config 1710 FPS850L_config Sandpoint8240_config sbc8260_config 1711 GENIETV_config TQM823L_config PIP405_config 1712 GEN860T_config EBONY_config FPS860L_config 1713 1714Note: for some board special configuration names may exist; check if 1715 additional information is available from the board vendor; for 1716 instance, the TQM8xxL systems run normally at 50 MHz and use a 1717 SCC for 10baseT ethernet; there are also systems with 80 MHz 1718 CPU clock, and an optional Fast Ethernet module is available 1719 for CPU's with FEC. You can select such additional "features" 1720 when chosing the configuration, i. e. 1721 1722 make TQM860L_config 1723 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1724 1725 make TQM860L_FEC_config 1726 - will configure for a TQM860L at 50MHz with FEC for ethernet 1727 1728 make TQM860L_80MHz_config 1729 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1730 interface 1731 1732 make TQM860L_FEC_80MHz_config 1733 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1734 1735 make TQM823L_LCD_config 1736 - will configure for a TQM823L with U-Boot console on LCD 1737 1738 make TQM823L_LCD_80MHz_config 1739 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1740 1741 etc. 1742 1743 1744 1745Finally, type "make all", and you should get some working U-Boot 1746images ready for downlod to / installation on your system: 1747 1748- "u-boot.bin" is a raw binary image 1749- "u-boot" is an image in ELF binary format 1750- "u-boot.srec" is in Motorola S-Record format 1751 1752 1753Please be aware that the Makefiles assume you are using GNU make, so 1754for instance on NetBSD you might need to use "gmake" instead of 1755native "make". 1756 1757 1758If the system board that you have is not listed, then you will need 1759to port U-Boot to your hardware platform. To do this, follow these 1760steps: 1761 17621. Add a new configuration option for your board to the toplevel 1763 "Makefile", using the existing entries as examples. 17642. Create a new directory to hold your board specific code. Add any 1765 files you need. 17663. If you're porting U-Boot to a new CPU, then also create a new 1767 directory to hold your CPU specific code. Add any files you need. 17684. Run "make config_name" with your new name. 17695. Type "make", and you should get a working "u-boot.srec" file 1770 to be installed on your target system. 1771 [Of course, this last step is much harder than it sounds.] 1772 1773 1774Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1775============================================================== 1776 1777If you have modified U-Boot sources (for instance added a new board 1778or support for new devices, a new CPU, etc.) you are expected to 1779provide feedback to the other developers. The feedback normally takes 1780the form of a "patch", i. e. a context diff against a certain (latest 1781official or latest in CVS) version of U-Boot sources. 1782 1783But before you submit such a patch, please verify that your modifi- 1784cation did not break existing code. At least make sure that *ALL* of 1785the supported boards compile WITHOUT ANY compiler warnings. To do so, 1786just run the "MAKEALL" script, which will configure and build U-Boot 1787for ALL supported system. Be warned, this will take a while. You can 1788select which (cross) compiler to use py passing a `CROSS_COMPILE' 1789environment variable to the script, i. e. to use the cross tools from 1790MontaVista's Hard Hat Linux you can type 1791 1792 CROSS_COMPILE=ppc_8xx- MAKEALL 1793 1794or to build on a native PowerPC system you can type 1795 1796 CROSS_COMPILE=' ' MAKEALL 1797 1798See also "U-Boot Porting Guide" below. 1799 1800 1801 1802Monitor Commands - Overview: 1803============================ 1804 1805go - start application at address 'addr' 1806run - run commands in an environment variable 1807bootm - boot application image from memory 1808bootp - boot image via network using BootP/TFTP protocol 1809tftpboot- boot image via network using TFTP protocol 1810 and env variables "ipaddr" and "serverip" 1811 (and eventually "gatewayip") 1812rarpboot- boot image via network using RARP/TFTP protocol 1813diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1814loads - load S-Record file over serial line 1815loadb - load binary file over serial line (kermit mode) 1816md - memory display 1817mm - memory modify (auto-incrementing) 1818nm - memory modify (constant address) 1819mw - memory write (fill) 1820cp - memory copy 1821cmp - memory compare 1822crc32 - checksum calculation 1823imd - i2c memory display 1824imm - i2c memory modify (auto-incrementing) 1825inm - i2c memory modify (constant address) 1826imw - i2c memory write (fill) 1827icrc32 - i2c checksum calculation 1828iprobe - probe to discover valid I2C chip addresses 1829iloop - infinite loop on address range 1830isdram - print SDRAM configuration information 1831sspi - SPI utility commands 1832base - print or set address offset 1833printenv- print environment variables 1834setenv - set environment variables 1835saveenv - save environment variables to persistent storage 1836protect - enable or disable FLASH write protection 1837erase - erase FLASH memory 1838flinfo - print FLASH memory information 1839bdinfo - print Board Info structure 1840iminfo - print header information for application image 1841coninfo - print console devices and informations 1842ide - IDE sub-system 1843loop - infinite loop on address range 1844mtest - simple RAM test 1845icache - enable or disable instruction cache 1846dcache - enable or disable data cache 1847reset - Perform RESET of the CPU 1848echo - echo args to console 1849version - print monitor version 1850help - print online help 1851? - alias for 'help' 1852 1853 1854Monitor Commands - Detailed Description: 1855======================================== 1856 1857TODO. 1858 1859For now: just type "help <command>". 1860 1861 1862Environment Variables: 1863====================== 1864 1865U-Boot supports user configuration using Environment Variables which 1866can be made persistent by saving to Flash memory. 1867 1868Environment Variables are set using "setenv", printed using 1869"printenv", and saved to Flash using "saveenv". Using "setenv" 1870without a value can be used to delete a variable from the 1871environment. As long as you don't save the environment you are 1872working with an in-memory copy. In case the Flash area containing the 1873environment is erased by accident, a default environment is provided. 1874 1875Some configuration options can be set using Environment Variables: 1876 1877 baudrate - see CONFIG_BAUDRATE 1878 1879 bootdelay - see CONFIG_BOOTDELAY 1880 1881 bootcmd - see CONFIG_BOOTCOMMAND 1882 1883 bootargs - Boot arguments when booting an RTOS image 1884 1885 bootfile - Name of the image to load with TFTP 1886 1887 autoload - if set to "no" (any string beginning with 'n'), 1888 "bootp" will just load perform a lookup of the 1889 configuration from the BOOTP server, but not try to 1890 load any image using TFTP 1891 1892 autostart - if set to "yes", an image loaded using the "bootp", 1893 "rarpboot", "tftpboot" or "diskboot" commands will 1894 be automatically started (by internally calling 1895 "bootm") 1896 1897 initrd_high - restrict positioning of initrd images: 1898 If this variable is not set, initrd images will be 1899 copied to the highest possible address in RAM; this 1900 is usually what you want since it allows for 1901 maximum initrd size. If for some reason you want to 1902 make sure that the initrd image is loaded below the 1903 CFG_BOOTMAPSZ limit, you can set this environment 1904 variable to a value of "no" or "off" or "0". 1905 Alternatively, you can set it to a maximum upper 1906 address to use (U-Boot will still check that it 1907 does not overwrite the U-Boot stack and data). 1908 1909 For instance, when you have a system with 16 MB 1910 RAM, and want to reseve 4 MB from use by Linux, 1911 you can do this by adding "mem=12M" to the value of 1912 the "bootargs" variable. However, now you must make 1913 sure, that the initrd image is placed in the first 1914 12 MB as well - this can be done with 1915 1916 setenv initrd_high 00c00000 1917 1918 ipaddr - IP address; needed for tftpboot command 1919 1920 loadaddr - Default load address for commands like "bootp", 1921 "rarpboot", "tftpboot" or "diskboot" 1922 1923 loads_echo - see CONFIG_LOADS_ECHO 1924 1925 serverip - TFTP server IP address; needed for tftpboot command 1926 1927 bootretry - see CONFIG_BOOT_RETRY_TIME 1928 1929 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1930 1931 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1932 1933 1934The following environment variables may be used and automatically 1935updated by the network boot commands ("bootp" and "rarpboot"), 1936depending the information provided by your boot server: 1937 1938 bootfile - see above 1939 dnsip - IP address of your Domain Name Server 1940 gatewayip - IP address of the Gateway (Router) to use 1941 hostname - Target hostname 1942 ipaddr - see above 1943 netmask - Subnet Mask 1944 rootpath - Pathname of the root filesystem on the NFS server 1945 serverip - see above 1946 1947 1948There are two special Environment Variables: 1949 1950 serial# - contains hardware identification information such 1951 as type string and/or serial number 1952 ethaddr - Ethernet address 1953 1954These variables can be set only once (usually during manufacturing of 1955the board). U-Boot refuses to delete or overwrite these variables 1956once they have been set once. 1957 1958 1959Please note that changes to some configuration parameters may take 1960only effect after the next boot (yes, that's just like Windoze :-). 1961 1962 1963Note for Redundant Ethernet Interfaces: 1964======================================= 1965 1966Some boards come with redundand ethernet interfaces; U-Boot supports 1967such configurations and is capable of automatic selection of a 1968"working" interface when needed. MAC assignemnt works as follows: 1969 1970Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1971MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1972"eth1addr" (=>eth1), "eth2addr", ... 1973 1974If the network interface stores some valid MAC address (for instance 1975in SROM), this is used as default address if there is NO correspon- 1976ding setting in the environment; if the corresponding environment 1977variable is set, this overrides the settings in the card; that means: 1978 1979o If the SROM has a valid MAC address, and there is no address in the 1980 environment, the SROM's address is used. 1981 1982o If there is no valid address in the SROM, and a definition in the 1983 environment exists, then the value from the environment variable is 1984 used. 1985 1986o If both the SROM and the environment contain a MAC address, and 1987 both addresses are the same, this MAC address is used. 1988 1989o If both the SROM and the environment contain a MAC address, and the 1990 addresses differ, the value from the environment is used and a 1991 warning is printed. 1992 1993o If neither SROM nor the environment contain a MAC address, an error 1994 is raised. 1995 1996 1997 1998Image Formats: 1999============== 2000 2001The "boot" commands of this monitor operate on "image" files which 2002can be basicly anything, preceeded by a special header; see the 2003definitions in include/image.h for details; basicly, the header 2004defines the following image properties: 2005 2006* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2007 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2008 LynxOS, pSOS, QNX; 2009 Currently supported: Linux, NetBSD, VxWorks, QNX). 2010* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2011 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2012 Currently supported: PowerPC). 2013* Compression Type (Provisions for uncompressed, gzip, bzip2; 2014 Currently supported: uncompressed, gzip). 2015* Load Address 2016* Entry Point 2017* Image Name 2018* Image Timestamp 2019 2020The header is marked by a special Magic Number, and both the header 2021and the data portions of the image are secured against corruption by 2022CRC32 checksums. 2023 2024 2025Linux Support: 2026============== 2027 2028Although U-Boot should support any OS or standalone application 2029easily, Linux has always been in the focus during the design of 2030U-Boot. 2031 2032U-Boot includes many features that so far have been part of some 2033special "boot loader" code within the Linux kernel. Also, any 2034"initrd" images to be used are no longer part of one big Linux image; 2035instead, kernel and "initrd" are separate images. This implementation 2036serves serveral purposes: 2037 2038- the same features can be used for other OS or standalone 2039 applications (for instance: using compressed images to reduce the 2040 Flash memory footprint) 2041 2042- it becomes much easier to port new Linux kernel versions because 2043 lots of low-level, hardware dependend stuff are done by U-Boot 2044 2045- the same Linux kernel image can now be used with different "initrd" 2046 images; of course this also means that different kernel images can 2047 be run with the same "initrd". This makes testing easier (you don't 2048 have to build a new "zImage.initrd" Linux image when you just 2049 change a file in your "initrd"). Also, a field-upgrade of the 2050 software is easier now. 2051 2052 2053Linux HOWTO: 2054============ 2055 2056Porting Linux to U-Boot based systems: 2057--------------------------------------- 2058 2059U-Boot cannot save you from doing all the necessary modifications to 2060configure the Linux device drivers for use with your target hardware 2061(no, we don't intend to provide a full virtual machine interface to 2062Linux :-). 2063 2064But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2065 2066Just make sure your machine specific header file (for instance 2067include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2068Information structure as we define in include/u-boot.h, and make 2069sure that your definition of IMAP_ADDR uses the same value as your 2070U-Boot configuration in CFG_IMMR. 2071 2072 2073Configuring the Linux kernel: 2074----------------------------- 2075 2076No specific requirements for U-Boot. Make sure you have some root 2077device (initial ramdisk, NFS) for your target system. 2078 2079 2080Building a Linux Image: 2081----------------------- 2082 2083With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2084not used. If you use recent kernel source, a new build target 2085"uImage" will exist which automatically builds an image usable by 2086U-Boot. Most older kernels also have support for a "pImage" target, 2087which was introduced for our predecessor project PPCBoot and uses a 2088100% compatible format. 2089 2090Example: 2091 2092 make TQM850L_config 2093 make oldconfig 2094 make dep 2095 make uImage 2096 2097The "uImage" build target uses a special tool (in 'tools/mkimage') to 2098encapsulate a compressed Linux kernel image with header information, 2099CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2100 2101* build a standard "vmlinux" kernel image (in ELF binary format): 2102 2103* convert the kernel into a raw binary image: 2104 2105 ${CROSS_COMPILE}-objcopy -O binary \ 2106 -R .note -R .comment \ 2107 -S vmlinux linux.bin 2108 2109* compress the binary image: 2110 2111 gzip -9 linux.bin 2112 2113* package compressed binary image for U-Boot: 2114 2115 mkimage -A ppc -O linux -T kernel -C gzip \ 2116 -a 0 -e 0 -n "Linux Kernel Image" \ 2117 -d linux.bin.gz uImage 2118 2119 2120The "mkimage" tool can also be used to create ramdisk images for use 2121with U-Boot, either separated from the Linux kernel image, or 2122combined into one file. "mkimage" encapsulates the images with a 64 2123byte header containing information about target architecture, 2124operating system, image type, compression method, entry points, time 2125stamp, CRC32 checksums, etc. 2126 2127"mkimage" can be called in two ways: to verify existing images and 2128print the header information, or to build new images. 2129 2130In the first form (with "-l" option) mkimage lists the information 2131contained in the header of an existing U-Boot image; this includes 2132checksum verification: 2133 2134 tools/mkimage -l image 2135 -l ==> list image header information 2136 2137The second form (with "-d" option) is used to build a U-Boot image 2138from a "data file" which is used as image payload: 2139 2140 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2141 -n name -d data_file image 2142 -A ==> set architecture to 'arch' 2143 -O ==> set operating system to 'os' 2144 -T ==> set image type to 'type' 2145 -C ==> set compression type 'comp' 2146 -a ==> set load address to 'addr' (hex) 2147 -e ==> set entry point to 'ep' (hex) 2148 -n ==> set image name to 'name' 2149 -d ==> use image data from 'datafile' 2150 2151Right now, all Linux kernels use the same load address (0x00000000), 2152but the entry point address depends on the kernel version: 2153 2154- 2.2.x kernels have the entry point at 0x0000000C, 2155- 2.3.x and later kernels have the entry point at 0x00000000. 2156 2157So a typical call to build a U-Boot image would read: 2158 2159 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2160 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2161 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2162 > examples/uImage.TQM850L 2163 Image Name: 2.4.4 kernel for TQM850L 2164 Created: Wed Jul 19 02:34:59 2000 2165 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2166 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2167 Load Address: 0x00000000 2168 Entry Point: 0x00000000 2169 2170To verify the contents of the image (or check for corruption): 2171 2172 -> tools/mkimage -l examples/uImage.TQM850L 2173 Image Name: 2.4.4 kernel for TQM850L 2174 Created: Wed Jul 19 02:34:59 2000 2175 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2176 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2177 Load Address: 0x00000000 2178 Entry Point: 0x00000000 2179 2180NOTE: for embedded systems where boot time is critical you can trade 2181speed for memory and install an UNCOMPRESSED image instead: this 2182needs more space in Flash, but boots much faster since it does not 2183need to be uncompressed: 2184 2185 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2186 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2187 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2188 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2189 > examples/uImage.TQM850L-uncompressed 2190 Image Name: 2.4.4 kernel for TQM850L 2191 Created: Wed Jul 19 02:34:59 2000 2192 Image Type: PowerPC Linux Kernel Image (uncompressed) 2193 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2194 Load Address: 0x00000000 2195 Entry Point: 0x00000000 2196 2197 2198Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2199when your kernel is intended to use an initial ramdisk: 2200 2201 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2202 > -A ppc -O linux -T ramdisk -C gzip \ 2203 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2204 Image Name: Simple Ramdisk Image 2205 Created: Wed Jan 12 14:01:50 2000 2206 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2207 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2208 Load Address: 0x00000000 2209 Entry Point: 0x00000000 2210 2211 2212Installing a Linux Image: 2213------------------------- 2214 2215To downloading a U-Boot image over the serial (console) interface, 2216you must convert the image to S-Record format: 2217 2218 objcopy -I binary -O srec examples/image examples/image.srec 2219 2220The 'objcopy' does not understand the information in the U-Boot 2221image header, so the resulting S-Record file will be relative to 2222address 0x00000000. To load it to a given address, you need to 2223specify the target address as 'offset' parameter with the 'loads' 2224command. 2225 2226Example: install the image to address 0x40100000 (which on the 2227TQM8xxL is in the first Flash bank): 2228 2229 => erase 40100000 401FFFFF 2230 2231 .......... done 2232 Erased 8 sectors 2233 2234 => loads 40100000 2235 ## Ready for S-Record download ... 2236 ~>examples/image.srec 2237 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2238 ... 2239 15989 15990 15991 15992 2240 [file transfer complete] 2241 [connected] 2242 ## Start Addr = 0x00000000 2243 2244 2245You can check the success of the download using the 'iminfo' command; 2246this includes a checksum verification so you can be sure no data 2247corruption happened: 2248 2249 => imi 40100000 2250 2251 ## Checking Image at 40100000 ... 2252 Image Name: 2.2.13 for initrd on TQM850L 2253 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2254 Data Size: 335725 Bytes = 327 kB = 0 MB 2255 Load Address: 00000000 2256 Entry Point: 0000000c 2257 Verifying Checksum ... OK 2258 2259 2260 2261Boot Linux: 2262----------- 2263 2264The "bootm" command is used to boot an application that is stored in 2265memory (RAM or Flash). In case of a Linux kernel image, the contents 2266of the "bootargs" environment variable is passed to the kernel as 2267parameters. You can check and modify this variable using the 2268"printenv" and "setenv" commands: 2269 2270 2271 => printenv bootargs 2272 bootargs=root=/dev/ram 2273 2274 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2275 2276 => printenv bootargs 2277 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2278 2279 => bootm 40020000 2280 ## Booting Linux kernel at 40020000 ... 2281 Image Name: 2.2.13 for NFS on TQM850L 2282 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2283 Data Size: 381681 Bytes = 372 kB = 0 MB 2284 Load Address: 00000000 2285 Entry Point: 0000000c 2286 Verifying Checksum ... OK 2287 Uncompressing Kernel Image ... OK 2288 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 2289 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2290 time_init: decrementer frequency = 187500000/60 2291 Calibrating delay loop... 49.77 BogoMIPS 2292 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2293 ... 2294 2295If you want to boot a Linux kernel with initial ram disk, you pass 2296the memory addreses of both the kernel and the initrd image (PPBCOOT 2297format!) to the "bootm" command: 2298 2299 => imi 40100000 40200000 2300 2301 ## Checking Image at 40100000 ... 2302 Image Name: 2.2.13 for initrd on TQM850L 2303 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2304 Data Size: 335725 Bytes = 327 kB = 0 MB 2305 Load Address: 00000000 2306 Entry Point: 0000000c 2307 Verifying Checksum ... OK 2308 2309 ## Checking Image at 40200000 ... 2310 Image Name: Simple Ramdisk Image 2311 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2312 Data Size: 566530 Bytes = 553 kB = 0 MB 2313 Load Address: 00000000 2314 Entry Point: 00000000 2315 Verifying Checksum ... OK 2316 2317 => bootm 40100000 40200000 2318 ## Booting Linux kernel at 40100000 ... 2319 Image Name: 2.2.13 for initrd on TQM850L 2320 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2321 Data Size: 335725 Bytes = 327 kB = 0 MB 2322 Load Address: 00000000 2323 Entry Point: 0000000c 2324 Verifying Checksum ... OK 2325 Uncompressing Kernel Image ... OK 2326 ## Loading RAMDisk Image at 40200000 ... 2327 Image Name: Simple Ramdisk Image 2328 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2329 Data Size: 566530 Bytes = 553 kB = 0 MB 2330 Load Address: 00000000 2331 Entry Point: 00000000 2332 Verifying Checksum ... OK 2333 Loading Ramdisk ... OK 2334 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 2335 Boot arguments: root=/dev/ram 2336 time_init: decrementer frequency = 187500000/60 2337 Calibrating delay loop... 49.77 BogoMIPS 2338 ... 2339 RAMDISK: Compressed image found at block 0 2340 VFS: Mounted root (ext2 filesystem). 2341 2342 bash# 2343 2344 2345Standalone HOWTO: 2346================= 2347 2348One of the features of U-Boot is that you can dynamically load and 2349run "standalone" applications, which can use some resources of 2350U-Boot like console I/O functions or interrupt services. 2351 2352Two simple examples are included with the sources: 2353 2354"Hello World" Demo: 2355------------------- 2356 2357'examples/hello_world.c' contains a small "Hello World" Demo 2358application; it is automatically compiled when you build U-Boot. 2359It's configured to run at address 0x00040004, so you can play with it 2360like that: 2361 2362 => loads 2363 ## Ready for S-Record download ... 2364 ~>examples/hello_world.srec 2365 1 2 3 4 5 6 7 8 9 10 11 ... 2366 [file transfer complete] 2367 [connected] 2368 ## Start Addr = 0x00040004 2369 2370 => go 40004 Hello World! This is a test. 2371 ## Starting application at 0x00040004 ... 2372 Hello World 2373 argc = 7 2374 argv[0] = "40004" 2375 argv[1] = "Hello" 2376 argv[2] = "World!" 2377 argv[3] = "This" 2378 argv[4] = "is" 2379 argv[5] = "a" 2380 argv[6] = "test." 2381 argv[7] = "<NULL>" 2382 Hit any key to exit ... 2383 2384 ## Application terminated, rc = 0x0 2385 2386Another example, which demonstrates how to register a CPM interrupt 2387handler with the U-Boot code, can be found in 'examples/timer.c'. 2388Here, a CPM timer is set up to generate an interrupt every second. 2389The interrupt service routine is trivial, just printing a '.' 2390character, but this is just a demo program. The application can be 2391controlled by the following keys: 2392 2393 ? - print current values og the CPM Timer registers 2394 b - enable interrupts and start timer 2395 e - stop timer and disable interrupts 2396 q - quit application 2397 2398 => loads 2399 ## Ready for S-Record download ... 2400 ~>examples/timer.srec 2401 1 2 3 4 5 6 7 8 9 10 11 ... 2402 [file transfer complete] 2403 [connected] 2404 ## Start Addr = 0x00040004 2405 2406 => go 40004 2407 ## Starting application at 0x00040004 ... 2408 TIMERS=0xfff00980 2409 Using timer 1 2410 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2411 2412Hit 'b': 2413 [q, b, e, ?] Set interval 1000000 us 2414 Enabling timer 2415Hit '?': 2416 [q, b, e, ?] ........ 2417 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2418Hit '?': 2419 [q, b, e, ?] . 2420 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2421Hit '?': 2422 [q, b, e, ?] . 2423 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2424Hit '?': 2425 [q, b, e, ?] . 2426 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2427Hit 'e': 2428 [q, b, e, ?] ...Stopping timer 2429Hit 'q': 2430 [q, b, e, ?] ## Application terminated, rc = 0x0 2431 2432 2433NetBSD Notes: 2434============= 2435 2436Starting at version 0.9.2, U-Boot supports NetBSD both as host 2437(build U-Boot) and target system (boots NetBSD/mpc8xx). 2438 2439Building requires a cross environment; it is known to work on 2440NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2441need gmake since the Makefiles are not compatible with BSD make). 2442Note that the cross-powerpc package does not install include files; 2443attempting to build U-Boot will fail because <machine/ansi.h> is 2444missing. This file has to be installed and patched manually: 2445 2446 # cd /usr/pkg/cross/powerpc-netbsd/include 2447 # mkdir powerpc 2448 # ln -s powerpc machine 2449 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2450 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2451 2452Native builds *don't* work due to incompatibilities between native 2453and U-Boot include files. 2454 2455Booting assumes that (the first part of) the image booted is a 2456stage-2 loader which in turn loads and then invokes the kernel 2457proper. Loader sources will eventually appear in the NetBSD source 2458tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2459meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2460details. 2461 2462 2463Implementation Internals: 2464========================= 2465 2466The following is not intended to be a complete description of every 2467implementation detail. However, it should help to understand the 2468inner workings of U-Boot and make it easier to port it to custom 2469hardware. 2470 2471 2472Initial Stack, Global Data: 2473--------------------------- 2474 2475The implementation of U-Boot is complicated by the fact that U-Boot 2476starts running out of ROM (flash memory), usually without access to 2477system RAM (because the memory controller is not initialized yet). 2478This means that we don't have writable Data or BSS segments, and BSS 2479is not initialized as zero. To be able to get a C environment working 2480at all, we have to allocate at least a minimal stack. Implementation 2481options for this are defined and restricted by the CPU used: Some CPU 2482models provide on-chip memory (like the IMMR area on MPC8xx and 2483MPC826x processors), on others (parts of) the data cache can be 2484locked as (mis-) used as memory, etc. 2485 2486It is essential to remember this, since it has some impact on the C 2487code for the initialization procedures: 2488 2489* Initialized global data (data segment) is read-only. Do not attempt 2490 to write it. 2491 2492* Do not use any unitialized global data (or implicitely initialized 2493 as zero data - BSS segment) at all - this is undefined, initiali- 2494 zation is performed later (when relocationg to RAM). 2495 2496* Stack space is very limited. Avoid big data buffers or things like 2497 that. 2498 2499Having only the stack as writable memory limits means we cannot use 2500normal global data to share information beween the code. But it 2501turned out that the implementation of U-Boot can be greatly 2502simplified by making a global data structure (gd_t) available to all 2503functions. We could pass a pointer to this data as argument to _all_ 2504functions, but this would bloat the code. Instead we use a feature of 2505the GCC compiler (Global Register Variables) to share the data: we 2506place a pointer (gd) to the global data into a register which we 2507reserve for this purpose. 2508 2509When chosing a register for such a purpose we are restricted by the 2510relevant (E)ABI specifications for the current architecture, and by 2511GCC's implementation. 2512 2513For PowerPC, the following registers have specific use: 2514 R1: stack pointer 2515 R2: TOC pointer 2516 R3-R4: parameter passing and return values 2517 R5-R10: parameter passing 2518 R13: small data area pointer 2519 R30: GOT pointer 2520 R31: frame pointer 2521 2522 (U-Boot also uses R14 as internal GOT pointer.) 2523 2524 ==> U-Boot will use R29 to hold a pointer to the global data 2525 2526 Note: on PPC, we could use a static initializer (since the 2527 address of the global data structure is known at compile time), 2528 but it turned out that reserving a register results in somewhat 2529 smaller code - although the code savings are not that big (on 2530 average for all boards 752 bytes for the whole U-Boot image, 2531 624 text + 127 data). 2532 2533On ARM, the following registers are used: 2534 2535 R0: function argument word/integer result 2536 R1-R3: function argument word 2537 R9: GOT pointer 2538 R10: stack limit (used only if stack checking if enabled) 2539 R11: argument (frame) pointer 2540 R12: temporary workspace 2541 R13: stack pointer 2542 R14: link register 2543 R15: program counter 2544 2545 ==> U-Boot will use R8 to hold a pointer to the global data 2546 2547 2548 2549Memory Management: 2550------------------ 2551 2552U-Boot runs in system state and uses physical addresses, i.e. the 2553MMU is not used either for address mapping nor for memory protection. 2554 2555The available memory is mapped to fixed addresses using the memory 2556controller. In this process, a contiguous block is formed for each 2557memory type (Flash, SDRAM, SRAM), even when it consists of several 2558physical memory banks. 2559 2560U-Boot is installed in the first 128 kB of the first Flash bank (on 2561TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2562booting and sizing and initializing DRAM, the code relocates itself 2563to the upper end of DRAM. Immediately below the U-Boot code some 2564memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2565configuration setting]. Below that, a structure with global Board 2566Info data is placed, followed by the stack (growing downward). 2567 2568Additionally, some exception handler code is copied to the low 8 kB 2569of DRAM (0x00000000 ... 0x00001FFF). 2570 2571So a typical memory configuration with 16 MB of DRAM could look like 2572this: 2573 2574 0x0000 0000 Exception Vector code 2575 : 2576 0x0000 1FFF 2577 0x0000 2000 Free for Application Use 2578 : 2579 : 2580 2581 : 2582 : 2583 0x00FB FF20 Monitor Stack (Growing downward) 2584 0x00FB FFAC Board Info Data and permanent copy of global data 2585 0x00FC 0000 Malloc Arena 2586 : 2587 0x00FD FFFF 2588 0x00FE 0000 RAM Copy of Monitor Code 2589 ... eventually: LCD or video framebuffer 2590 ... eventually: pRAM (Protected RAM - unchanged by reset) 2591 0x00FF FFFF [End of RAM] 2592 2593 2594System Initialization: 2595---------------------- 2596 2597In the reset configuration, U-Boot starts at the reset entry point 2598(on most PowerPC systens at address 0x00000100). Because of the reset 2599configuration for CS0# this is a mirror of the onboard Flash memory. 2600To be able to re-map memory U-Boot then jumps to it's link address. 2601To be able to implement the initialization code in C, a (small!) 2602initial stack is set up in the internal Dual Ported RAM (in case CPUs 2603which provide such a feature like MPC8xx or MPC8260), or in a locked 2604part of the data cache. After that, U-Boot initializes the CPU core, 2605the caches and the SIU. 2606 2607Next, all (potentially) available memory banks are mapped using a 2608preliminary mapping. For example, we put them on 512 MB boundaries 2609(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2610on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2611programmed for SDRAM access. Using the temporary configuration, a 2612simple memory test is run that determines the size of the SDRAM 2613banks. 2614 2615When there is more than one SDRAM bank, and the banks are of 2616different size, the larger is mapped first. For equal size, the first 2617bank (CS2#) is mapped first. The first mapping is always for address 26180x00000000, with any additional banks following immediately to create 2619contiguous memory starting from 0. 2620 2621Then, the monitor installs itself at the upper end of the SDRAM area 2622and allocates memory for use by malloc() and for the global Board 2623Info data; also, the exception vector code is copied to the low RAM 2624pages, and the final stack is set up. 2625 2626Only after this relocation will you have a "normal" C environment; 2627until that you are restricted in several ways, mostly because you are 2628running from ROM, and because the code will have to be relocated to a 2629new address in RAM. 2630 2631 2632U-Boot Porting Guide: 2633---------------------- 2634 2635[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2636list, Octover 2002] 2637 2638 2639int main (int argc, char *argv[]) 2640{ 2641 sighandler_t no_more_time; 2642 2643 signal (SIGALRM, no_more_time); 2644 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2645 2646 if (available_money > available_manpower) { 2647 pay consultant to port U-Boot; 2648 return 0; 2649 } 2650 2651 Download latest U-Boot source; 2652 2653 if (clueless) { 2654 email ("Hi, I am new to U-Boot, how do I get started?"); 2655 } 2656 2657 while (learning) { 2658 Read the README file in the top level directory; 2659 Read http://www.denx.de/re/DPLG.html 2660 Read the source, Luke; 2661 } 2662 2663 if (available_money > toLocalCurrency ($2500)) { 2664 Buy a BDI2000; 2665 } else { 2666 Add a lot of aggravation and time; 2667 } 2668 2669 Create your own board support subdirectory; 2670 2671 while (!running) { 2672 do { 2673 Add / modify source code; 2674 } until (compiles); 2675 Debug; 2676 if (clueless) 2677 email ("Hi, I am having problems..."); 2678 } 2679 Send patch file to Wolfgang; 2680 2681 return 0; 2682} 2683 2684void no_more_time (int sig) 2685{ 2686 hire_a_guru(); 2687} 2688 2689 2690 2691Coding Standards: 2692----------------- 2693 2694All contributions to U-Boot should conform to the Linux kernel 2695coding style; see the file "Documentation/CodingStyle" in your Linux 2696kernel source directory. 2697 2698Please note that U-Boot is implemented in C (and to some small parts 2699in Assembler); no C++ is used, so please do not use C++ style 2700comments (//) in your code. 2701 2702Submissions which do not conform to the standards may be returned 2703with a request to reformat the changes. 2704 2705 2706Submitting Patches: 2707------------------- 2708 2709Since the number of patches for U-Boot is growing, we need to 2710establish some rules. Submissions which do not conform to these rules 2711may be rejected, even when they contain important and valuable stuff. 2712 2713 2714When you send a patch, please include the following information with 2715it: 2716 2717* For bug fixes: a description of the bug and how your patch fixes 2718 this bug. Please try to include a way of demonstrating that the 2719 patch actually fixes something. 2720 2721* For new features: a description of the feature and your 2722 implementation. 2723 2724* A CHANGELOG entry as plaintext (separate from the patch) 2725 2726* For major contributions, your entry to the CREDITS file 2727 2728* When you add support for a new board, don't forget to add this 2729 board to the MAKEALL script, too. 2730 2731* If your patch adds new configuration options, don't forget to 2732 document these in the README file. 2733 2734* The patch itself. If you are accessing the CVS repository use "cvs 2735 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2736 version of diff does not support these options, then get the latest 2737 version of GNU diff. 2738 2739 We accept patches as plain text, MIME attachments or as uuencoded 2740 gzipped text. 2741 2742Notes: 2743 2744* Before sending the patch, run the MAKEALL script on your patched 2745 source tree and make sure that no errors or warnings are reported 2746 for any of the boards. 2747 2748* Keep your modifications to the necessary minimum: A patch 2749 containing several unrelated changes or arbitrary reformats will be 2750 returned with a request to re-formatting / split it. 2751 2752* If you modify existing code, make sure that your new code does not 2753 add to the memory footprint of the code ;-) Small is beautiful! 2754 When adding new features, these should compile conditionally only 2755 (using #ifdef), and the resulting code with the new feature 2756 disabled must not need more memory than the old code without your 2757 modification. 2758