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 269The following options need to be configured: 270 271- CPU Type: Define exactly one of 272 273 PowerPC based CPUs: 274 ------------------- 275 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 276 or CONFIG_MPC824X, CONFIG_MPC8260 277 or CONFIG_IOP480 278 or CONFIG_405GP 279 or CONFIG_440 280 or CONFIG_MPC74xx 281 282 ARM based CPUs: 283 --------------- 284 CONFIG_SA1110 285 CONFIG_ARM7 286 CONFIG_PXA250 287 288 289- Board Type: Define exactly one of 290 291 PowerPC based boards: 292 --------------------- 293 294 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 295 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 296 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 297 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 298 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 299 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 300 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 301 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 302 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 303 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 304 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 305 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 306 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 307 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 308 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 309 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 310 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 311 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 312 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 313 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 314 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 315 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 316 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 317 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 318 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 319 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 320 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 321 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 322 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 323 CONFIG_EBONY, CONFIG_sacsng 324 325 ARM based boards: 326 ----------------- 327 328 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 329 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 330 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 331 CONFIG_TRAB 332 333 334- CPU Module Type: (if CONFIG_COGENT is defined) 335 Define exactly one of 336 CONFIG_CMA286_60_OLD 337--- FIXME --- not tested yet: 338 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 339 CONFIG_CMA287_23, CONFIG_CMA287_50 340 341- Motherboard Type: (if CONFIG_COGENT is defined) 342 Define exactly one of 343 CONFIG_CMA101, CONFIG_CMA102 344 345- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 346 Define one or more of 347 CONFIG_CMA302 348 349- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 350 Define one or more of 351 CONFIG_LCD_HEARTBEAT - update a character position on 352 the lcd display every second with 353 a "rotator" |\-/|\-/ 354 355- MPC824X Family Member (if CONFIG_MPC824X is defined) 356 Define exactly one of 357 CONFIG_MPC8240, CONFIG_MPC8245 358 359- 8xx CPU Options: (if using an 8xx cpu) 360 Define one or more of 361 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 362 no 32KHz reference PIT/RTC clock 363 364- Clock Interface: 365 CONFIG_CLOCKS_IN_MHZ 366 367 U-Boot stores all clock information in Hz 368 internally. For binary compatibility with older Linux 369 kernels (which expect the clocks passed in the 370 bd_info data to be in MHz) the environment variable 371 "clocks_in_mhz" can be defined so that U-Boot 372 converts clock data to MHZ before passing it to the 373 Linux kernel. 374 375 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 376 "clocks_in_mhz=1" is automatically included in the 377 default environment. 378 379- Console Interface: 380 Depending on board, define exactly one serial port 381 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 382 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 383 console by defining CONFIG_8xx_CONS_NONE 384 385 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 386 port routines must be defined elsewhere 387 (i.e. serial_init(), serial_getc(), ...) 388 389 CONFIG_CFB_CONSOLE 390 Enables console device for a color framebuffer. Needs following 391 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 392 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 393 (default big endian) 394 VIDEO_HW_RECTFILL graphic chip supports 395 rectangle fill 396 (cf. smiLynxEM) 397 VIDEO_HW_BITBLT graphic chip supports 398 bit-blit (cf. smiLynxEM) 399 VIDEO_VISIBLE_COLS visible pixel columns 400 (cols=pitch) 401 VIDEO_VISIBLE_ROWS visible pixel rows 402 VIDEO_PIXEL_SIZE bytes per pixel 403 VIDEO_DATA_FORMAT graphic data format 404 (0-5, cf. cfb_console.c) 405 VIDEO_FB_ADRS framebuffer address 406 VIDEO_KBD_INIT_FCT keyboard int fct 407 (i.e. i8042_kbd_init()) 408 VIDEO_TSTC_FCT test char fct 409 (i.e. i8042_tstc) 410 VIDEO_GETC_FCT get char fct 411 (i.e. i8042_getc) 412 CONFIG_CONSOLE_CURSOR cursor drawing on/off 413 (requires blink timer 414 cf. i8042.c) 415 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 416 CONFIG_CONSOLE_TIME display time/date info in 417 upper right corner 418 (requires CFG_CMD_DATE) 419 CONFIG_VIDEO_LOGO display Linux logo in 420 upper left corner 421 CONFIG_CONSOLE_EXTRA_INFO 422 addional board info beside 423 the logo 424 425 When CONFIG_CFB_CONSOLE is defined, video console is 426 default i/o. Serial console can be forced with 427 environment 'console=serial'. 428 429- Console Baudrate: 430 CONFIG_BAUDRATE - in bps 431 Select one of the baudrates listed in 432 CFG_BAUDRATE_TABLE, see below. 433 434- Interrupt driven serial port input: 435 CONFIG_SERIAL_SOFTWARE_FIFO 436 437 PPC405GP only. 438 Use an interrupt handler for receiving data on the 439 serial port. It also enables using hardware handshake 440 (RTS/CTS) and UART's built-in FIFO. Set the number of 441 bytes the interrupt driven input buffer should have. 442 443 Set to 0 to disable this feature (this is the default). 444 This will also disable hardware handshake. 445 446- Boot Delay: CONFIG_BOOTDELAY - in seconds 447 Delay before automatically booting the default image; 448 set to -1 to disable autoboot. 449 450 See doc/README.autoboot for these options that 451 work with CONFIG_BOOTDELAY. None are required. 452 CONFIG_BOOT_RETRY_TIME 453 CONFIG_BOOT_RETRY_MIN 454 CONFIG_AUTOBOOT_KEYED 455 CONFIG_AUTOBOOT_PROMPT 456 CONFIG_AUTOBOOT_DELAY_STR 457 CONFIG_AUTOBOOT_STOP_STR 458 CONFIG_AUTOBOOT_DELAY_STR2 459 CONFIG_AUTOBOOT_STOP_STR2 460 CONFIG_ZERO_BOOTDELAY_CHECK 461 CONFIG_RESET_TO_RETRY 462 463- Autoboot Command: 464 CONFIG_BOOTCOMMAND 465 Only needed when CONFIG_BOOTDELAY is enabled; 466 define a command string that is automatically executed 467 when no character is read on the console interface 468 within "Boot Delay" after reset. 469 470 CONFIG_BOOTARGS 471 This can be used to pass arguments to the bootm 472 command. The value of CONFIG_BOOTARGS goes into the 473 environment value "bootargs". 474 475 CONFIG_RAMBOOT and CONFIG_NFSBOOT 476 The value of these goes into the environment as 477 "ramboot" and "nfsboot" respectively, and can be used 478 as a convenience, when switching between booting from 479 ram and nfs. 480 481- Pre-Boot Commands: 482 CONFIG_PREBOOT 483 484 When this option is #defined, the existence of the 485 environment variable "preboot" will be checked 486 immediately before starting the CONFIG_BOOTDELAY 487 countdown and/or running the auto-boot command resp. 488 entering interactive mode. 489 490 This feature is especially useful when "preboot" is 491 automatically generated or modified. For an example 492 see the LWMON board specific code: here "preboot" is 493 modified when the user holds down a certain 494 combination of keys on the (special) keyboard when 495 booting the systems 496 497- Serial Download Echo Mode: 498 CONFIG_LOADS_ECHO 499 If defined to 1, all characters received during a 500 serial download (using the "loads" command) are 501 echoed back. This might be needed by some terminal 502 emulations (like "cu"), but may as well just take 503 time on others. This setting #define's the initial 504 value of the "loads_echo" environment variable. 505 506- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 507 CONFIG_KGDB_BAUDRATE 508 Select one of the baudrates listed in 509 CFG_BAUDRATE_TABLE, see below. 510 511- Monitor Functions: 512 CONFIG_COMMANDS 513 Most monitor functions can be selected (or 514 de-selected) by adjusting the definition of 515 CONFIG_COMMANDS; to select individual functions, 516 #define CONFIG_COMMANDS by "OR"ing any of the 517 following values: 518 519 #define enables commands: 520 ------------------------- 521 CFG_CMD_ASKENV * ask for env variable 522 CFG_CMD_BDI bdinfo 523 CFG_CMD_BEDBUG Include BedBug Debugger 524 CFG_CMD_BOOTD bootd 525 CFG_CMD_CACHE icache, dcache 526 CFG_CMD_CONSOLE coninfo 527 CFG_CMD_DATE * support for RTC, date/time... 528 CFG_CMD_DHCP DHCP support 529 CFG_CMD_ECHO * echo arguments 530 CFG_CMD_EEPROM * EEPROM read/write support 531 CFG_CMD_ELF bootelf, bootvx 532 CFG_CMD_ENV saveenv 533 CFG_CMD_FDC * Floppy Disk Support 534 CFG_CMD_FLASH flinfo, erase, protect 535 CFG_CMD_FPGA FPGA device initialization support 536 CFG_CMD_I2C * I2C serial bus support 537 CFG_CMD_IDE * IDE harddisk support 538 CFG_CMD_IMI iminfo 539 CFG_CMD_IMMAP * IMMR dump support 540 CFG_CMD_IRQ * irqinfo 541 CFG_CMD_KGDB * kgdb 542 CFG_CMD_LOADB loadb 543 CFG_CMD_LOADS loads 544 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 545 loop, mtest 546 CFG_CMD_MII MII utility commands 547 CFG_CMD_NET bootp, tftpboot, rarpboot 548 CFG_CMD_PCI * pciinfo 549 CFG_CMD_PCMCIA * PCMCIA support 550 CFG_CMD_REGINFO * Register dump 551 CFG_CMD_RUN run command in env variable 552 CFG_CMD_SCSI * SCSI Support 553 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 554 CFG_CMD_SPI * SPI serial bus support 555 CFG_CMD_USB * USB support 556 CFG_CMD_BSP * Board SPecific functions 557 ----------------------------------------------- 558 CFG_CMD_ALL all 559 560 CFG_CMD_DFL Default configuration; at the moment 561 this is includes all commands, except 562 the ones marked with "*" in the list 563 above. 564 565 If you don't define CONFIG_COMMANDS it defaults to 566 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 567 override the default settings in the respective 568 include file. 569 570 EXAMPLE: If you want all functions except of network 571 support you can write: 572 573 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 574 575 576 Note: Don't enable the "icache" and "dcache" commands 577 (configuration option CFG_CMD_CACHE) unless you know 578 what you (and your U-Boot users) are doing. Data 579 cache cannot be enabled on systems like the 8xx or 580 8260 (where accesses to the IMMR region must be 581 uncached), and it cannot be disabled on all other 582 systems where we (mis-) use the data cache to hold an 583 initial stack and some data. 584 585 586 XXX - this list needs to get updated! 587 588- Watchdog: 589 CONFIG_WATCHDOG 590 If this variable is defined, it enables watchdog 591 support. There must support in the platform specific 592 code for a watchdog. For the 8xx and 8260 CPUs, the 593 SIU Watchdog feature is enabled in the SYPCR 594 register. 595 596- Real-Time Clock: 597 598 When CFG_CMD_DATE is selected, the type of the RTC 599 has to be selected, too. Define exactly one of the 600 following options: 601 602 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 603 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 604 CONFIG_RTC_MC146818 - use MC146818 RTC 605 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 606 607- Timestamp Support: 608 609 When CONFIG_TIMESTAMP is selected, the timestamp 610 (date and time) of an image is printed by image 611 commands like bootm or iminfo. This option is 612 automatically enabled when you select CFG_CMD_DATE . 613 614- Partition Support: 615 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 616 and/or CONFIG_ISO_PARTITION 617 618 If IDE or SCSI support is enabled (CFG_CMD_IDE or 619 CFG_CMD_SCSI) you must configure support for at least 620 one partition type as well. 621 622- IDE Reset method: 623 CONFIG_IDE_RESET_ROUTINE 624 625 Set this to define that instead of a reset Pin, the 626 routine ide_set_reset(int idereset) will be used. 627 628- ATAPI Support: 629 CONFIG_ATAPI 630 631 Set this to enable ATAPI support. 632 633- SCSI Support: 634 At the moment only there is only support for the 635 SYM53C8XX SCSI controller; define 636 CONFIG_SCSI_SYM53C8XX to enable it. 637 638 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 639 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 640 CFG_SCSI_MAX_LUN] can be adjusted to define the 641 maximum numbers of LUNs, SCSI ID's and target 642 devices. 643 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 644 645- NETWORK Support (PCI): 646 CONFIG_EEPRO100 647 Support for Intel 82557/82559/82559ER chips. 648 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 649 write routine for first time initialisation. 650 651 CONFIG_TULIP 652 Support for Digital 2114x chips. 653 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 654 modem chip initialisation (KS8761/QS6611). 655 656 CONFIG_NATSEMI 657 Support for National dp83815 chips. 658 659 CONFIG_NS8382X 660 Support for National dp8382[01] gigabit chips. 661 662- USB Support: 663 At the moment only the UHCI host controller is 664 supported (PIP405, MIP405); define 665 CONFIG_USB_UHCI to enable it. 666 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 667 end define CONFIG_USB_STORAGE to enable the USB 668 storage devices. 669 Note: 670 Supported are USB Keyboards and USB Floppy drives 671 (TEAC FD-05PUB). 672 673- Keyboard Support: 674 CONFIG_ISA_KEYBOARD 675 676 Define this to enable standard (PC-Style) keyboard 677 support 678 679 CONFIG_I8042_KBD 680 Standard PC keyboard driver with US (is default) and 681 GERMAN key layout (switch via environment 'keymap=de') support. 682 Export function i8042_kbd_init, i8042_tstc and i8042_getc 683 for cfb_console. Supports cursor blinking. 684 685- Video support: 686 CONFIG_VIDEO 687 688 Define this to enable video support (for output to 689 video). 690 691 CONFIG_VIDEO_CT69000 692 693 Enable Chips & Technologies 69000 Video chip 694 695 CONFIG_VIDEO_SMI_LYNXEM 696 Enable Silicon Motion SMI 712/710/810 Video chip 697 Videomode are selected via environment 'videomode' with 698 standard LiLo mode numbers. 699 Following modes are supported (* is default): 700 701 800x600 1024x768 1280x1024 702 256 (8bit) 303* 305 307 703 65536 (16bit) 314 317 31a 704 16,7 Mill (24bit) 315 318 31b 705 (i.e. setenv videomode 317; saveenv; reset;) 706 707- LCD Support: CONFIG_LCD 708 709 Define this to enable LCD support (for output to LCD 710 display); also select one of the supported displays 711 by defining one of these: 712 713 CONFIG_NEC_NL6648AC33: 714 715 NEC NL6648AC33-18. Active, color, single scan. 716 717 CONFIG_NEC_NL6648BC20 718 719 NEC NL6648BC20-08. 6.5", 640x480. 720 Active, color, single scan. 721 722 CONFIG_SHARP_16x9 723 724 Sharp 320x240. Active, color, single scan. 725 It isn't 16x9, and I am not sure what it is. 726 727 CONFIG_SHARP_LQ64D341 728 729 Sharp LQ64D341 display, 640x480. 730 Active, color, single scan. 731 732 CONFIG_HLD1045 733 734 HLD1045 display, 640x480. 735 Active, color, single scan. 736 737 CONFIG_OPTREX_BW 738 739 Optrex CBL50840-2 NF-FW 99 22 M5 740 or 741 Hitachi LMG6912RPFC-00T 742 or 743 Hitachi SP14Q002 744 745 320x240. Black & white. 746 747 Normally display is black on white background; define 748 CFG_WHITE_ON_BLACK to get it inverted. 749 750- Ethernet address: 751 CONFIG_ETHADDR 752 CONFIG_ETH2ADDR 753 CONFIG_ETH3ADDR 754 755 Define a default value for ethernet address to use 756 for the respective ethernet interface, in case this 757 is not determined automatically. 758 759- IP address: 760 CONFIG_IPADDR 761 762 Define a default value for the IP address to use for 763 the default ethernet interface, in case this is not 764 determined through e.g. bootp. 765 766- Server IP address: 767 CONFIG_SERVERIP 768 769 Defines a default value for theIP address of a TFTP 770 server to contact when using the "tftboot" command. 771 772- BOOTP Recovery Mode: 773 CONFIG_BOOTP_RANDOM_DELAY 774 775 If you have many targets in a network that try to 776 boot using BOOTP, you may want to avoid that all 777 systems send out BOOTP requests at precisely the same 778 moment (which would happen for instance at recovery 779 from a power failure, when all systems will try to 780 boot, thus flooding the BOOTP server. Defining 781 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 782 inserted before sending out BOOTP requests. The 783 following delays are insterted then: 784 785 1st BOOTP request: delay 0 ... 1 sec 786 2nd BOOTP request: delay 0 ... 2 sec 787 3rd BOOTP request: delay 0 ... 4 sec 788 4th and following 789 BOOTP requests: delay 0 ... 8 sec 790 791- Status LED: CONFIG_STATUS_LED 792 793 Several configurations allow to display the current 794 status using a LED. For instance, the LED will blink 795 fast while running U-Boot code, stop blinking as 796 soon as a reply to a BOOTP request was received, and 797 start blinking slow once the Linux kernel is running 798 (supported by a status LED driver in the Linux 799 kernel). Defining CONFIG_STATUS_LED enables this 800 feature in U-Boot. 801 802- CAN Support: CONFIG_CAN_DRIVER 803 804 Defining CONFIG_CAN_DRIVER enables CAN driver support 805 on those systems that support this (optional) 806 feature, like the TQM8xxL modules. 807 808- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 809 810 Enables I2C serial bus commands. If this is selected, 811 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 812 to include the appropriate I2C driver. 813 814 See also: common/cmd_i2c.c for a description of the 815 command line interface. 816 817 818 CONFIG_HARD_I2C 819 820 Selects the CPM hardware driver for I2C. 821 822 CONFIG_SOFT_I2C 823 824 Use software (aka bit-banging) driver instead of CPM 825 or similar hardware support for I2C. This is configured 826 via the following defines. 827 828 I2C_INIT 829 830 (Optional). Any commands necessary to enable I2C 831 controller or configure ports. 832 833 I2C_PORT 834 835 (Only for MPC8260 CPU). The I/O port to use (the code 836 assumes both bits are on the same port). Valid values 837 are 0..3 for ports A..D. 838 839 I2C_ACTIVE 840 841 The code necessary to make the I2C data line active 842 (driven). If the data line is open collector, this 843 define can be null. 844 845 I2C_TRISTATE 846 847 The code necessary to make the I2C data line tri-stated 848 (inactive). If the data line is open collector, this 849 define can be null. 850 851 I2C_READ 852 853 Code that returns TRUE if the I2C data line is high, 854 FALSE if it is low. 855 856 I2C_SDA(bit) 857 858 If <bit> is TRUE, sets the I2C data line high. If it 859 is FALSE, it clears it (low). 860 861 I2C_SCL(bit) 862 863 If <bit> is TRUE, sets the I2C clock line high. If it 864 is FALSE, it clears it (low). 865 866 I2C_DELAY 867 868 This delay is invoked four times per clock cycle so this 869 controls the rate of data transfer. The data rate thus 870 is 1 / (I2C_DELAY * 4). 871 872- SPI Support: CONFIG_SPI 873 874 Enables SPI driver (so far only tested with 875 SPI EEPROM, also an instance works with Crystal A/D and 876 D/As on the SACSng board) 877 878 CONFIG_SPI_X 879 880 Enables extended (16-bit) SPI EEPROM addressing. 881 (symmetrical to CONFIG_I2C_X) 882 883 CONFIG_SOFT_SPI 884 885 Enables a software (bit-bang) SPI driver rather than 886 using hardware support. This is a general purpose 887 driver that only requires three general I/O port pins 888 (two outputs, one input) to function. If this is 889 defined, the board configuration must define several 890 SPI configuration items (port pins to use, etc). For 891 an example, see include/configs/sacsng.h. 892 893- FPGA Support: CONFIG_FPGA_COUNT 894 895 Specify the number of FPGA devices to support. 896 897 CONFIG_FPGA 898 899 Used to specify the types of FPGA devices. For 900 example, 901 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 902 903 CFG_FPGA_PROG_FEEDBACK 904 905 Enable printing of hash marks during FPGA 906 configuration. 907 908 CFG_FPGA_CHECK_BUSY 909 910 Enable checks on FPGA configuration interface busy 911 status by the configuration function. This option 912 will require a board or device specific function to 913 be written. 914 915 CONFIG_FPGA_DELAY 916 917 If defined, a function that provides delays in the 918 FPGA configuration driver. 919 920 CFG_FPGA_CHECK_CTRLC 921 922 Allow Control-C to interrupt FPGA configuration 923 924 CFG_FPGA_CHECK_ERROR 925 926 Check for configuration errors during FPGA bitfile 927 loading. For example, abort during Virtex II 928 configuration if the INIT_B line goes low (which 929 indicated a CRC error). 930 931 CFG_FPGA_WAIT_INIT 932 933 Maximum time to wait for the INIT_B line to deassert 934 after PROB_B has been deasserted during a Virtex II 935 FPGA configuration sequence. The default time is 500 mS. 936 937 CFG_FPGA_WAIT_BUSY 938 939 Maximum time to wait for BUSY to deassert during 940 Virtex II FPGA configuration. The default is 5 mS. 941 942 CFG_FPGA_WAIT_CONFIG 943 944 Time to wait after FPGA configuration. The default is 945 200 mS. 946 947- FPGA Support: CONFIG_FPGA_COUNT 948 949 Specify the number of FPGA devices to support. 950 951 CONFIG_FPGA 952 953 Used to specify the types of FPGA devices. For example, 954 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 955 956 CFG_FPGA_PROG_FEEDBACK 957 958 Enable printing of hash marks during FPGA configuration. 959 960 CFG_FPGA_CHECK_BUSY 961 962 Enable checks on FPGA configuration interface busy 963 status by the configuration function. This option 964 will require a board or device specific function to 965 be written. 966 967 CONFIG_FPGA_DELAY 968 969 If defined, a function that provides delays in the FPGA 970 configuration driver. 971 972 CFG_FPGA_CHECK_CTRLC 973 Allow Control-C to interrupt FPGA configuration 974 975 CFG_FPGA_CHECK_ERROR 976 977 Check for configuration errors during FPGA bitfile 978 loading. For example, abort during Virtex II 979 configuration if the INIT_B line goes low (which 980 indicated a CRC error). 981 982 CFG_FPGA_WAIT_INIT 983 984 Maximum time to wait for the INIT_B line to deassert 985 after PROB_B has been deasserted during a Virtex II 986 FPGA configuration sequence. The default time is 500 987 mS. 988 989 CFG_FPGA_WAIT_BUSY 990 991 Maximum time to wait for BUSY to deassert during 992 Virtex II FPGA configuration. The default is 5 mS. 993 994 CFG_FPGA_WAIT_CONFIG 995 996 Time to wait after FPGA configuration. The default is 997 200 mS. 998 999- Configuration Management: 1000 CONFIG_IDENT_STRING 1001 1002 If defined, this string will be added to the U-Boot 1003 version information (U_BOOT_VERSION) 1004 1005- Vendor Parameter Protection: 1006 1007 U-Boot considers the values of the environment 1008 variables "serial#" (Board Serial Number) and 1009 "ethaddr" (Ethernet Address) to bb parameters that 1010 are set once by the board vendor / manufacturer, and 1011 protects these variables from casual modification by 1012 the user. Once set, these variables are read-only, 1013 and write or delete attempts are rejected. You can 1014 change this behviour: 1015 1016 If CONFIG_ENV_OVERWRITE is #defined in your config 1017 file, the write protection for vendor parameters is 1018 completely disabled. Anybody can change or delte 1019 these parameters. 1020 1021 Alternatively, if you #define _both_ CONFIG_ETHADDR 1022 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1023 ethernet address is installed in the environment, 1024 which can be changed exactly ONCE by the user. [The 1025 serial# is unaffected by this, i. e. it remains 1026 read-only.] 1027 1028- Protected RAM: 1029 CONFIG_PRAM 1030 1031 Define this variable to enable the reservation of 1032 "protected RAM", i. e. RAM which is not overwritten 1033 by U-Boot. Define CONFIG_PRAM to hold the number of 1034 kB you want to reserve for pRAM. You can overwrite 1035 this default value by defining an environment 1036 variable "pram" to the number of kB you want to 1037 reserve. Note that the board info structure will 1038 still show the full amount of RAM. If pRAM is 1039 reserved, a new environment variable "mem" will 1040 automatically be defined to hold the amount of 1041 remaining RAM in a form that can be passed as boot 1042 argument to Linux, for instance like that: 1043 1044 setenv bootargs ... mem=\$(mem) 1045 saveenv 1046 1047 This way you can tell Linux not to use this memory, 1048 either, which results in a memory region that will 1049 not be affected by reboots. 1050 1051 *WARNING* If your board configuration uses automatic 1052 detection of the RAM size, you must make sure that 1053 this memory test is non-destructive. So far, the 1054 following board configurations are known to be 1055 "pRAM-clean": 1056 1057 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1058 HERMES, IP860, RPXlite, LWMON, LANTEC, 1059 PCU_E, FLAGADM, TQM8260 1060 1061- Error Recovery: 1062 CONFIG_PANIC_HANG 1063 1064 Define this variable to stop the system in case of a 1065 fatal error, so that you have to reset it manually. 1066 This is probably NOT a good idea for an embedded 1067 system where you want to system to reboot 1068 automatically as fast as possible, but it may be 1069 useful during development since you can try to debug 1070 the conditions that lead to the situation. 1071 1072 CONFIG_NET_RETRY_COUNT 1073 1074 This variable defines the number of retries for 1075 network operations like ARP, RARP, TFTP, or BOOTP 1076 before giving up the operation. If not defined, a 1077 default value of 5 is used. 1078 1079- Command Interpreter: 1080 CFG_HUSH_PARSER 1081 1082 Define this variable to enable the "hush" shell (from 1083 Busybox) as command line interpreter, thus enabling 1084 powerful command line syntax like 1085 if...then...else...fi conditionals or `&&' and '||' 1086 constructs ("shell scripts"). 1087 1088 If undefined, you get the old, much simpler behaviour 1089 with a somewhat smaller memory footprint. 1090 1091 1092 CFG_PROMPT_HUSH_PS2 1093 1094 This defines the secondary prompt string, which is 1095 printed when the command interpreter needs more input 1096 to complete a command. Usually "> ". 1097 1098 Note: 1099 1100 In the current implementation, the local variables 1101 space and global environment variables space are 1102 separated. Local variables are those you define by 1103 simply typing like `name=value'. To access a local 1104 variable later on, you have write `$name' or 1105 `${name}'; variable directly by typing say `$name' at 1106 the command prompt. 1107 1108 Global environment variables are those you use 1109 setenv/printenv to work with. To run a command stored 1110 in such a variable, you need to use the run command, 1111 and you must not use the '$' sign to access them. 1112 1113 To store commands and special characters in a 1114 variable, please use double quotation marks 1115 surrounding the whole text of the variable, instead 1116 of the backslashes before semicolons and special 1117 symbols. 1118 1119- Default Environment 1120 CONFIG_EXTRA_ENV_SETTINGS 1121 1122 Define this to contain any number of null terminated 1123 strings (variable = value pairs) that will be part of 1124 the default enviroment compiled into the boot image. 1125 For example, place something like this in your 1126 board's config file: 1127 1128 #define CONFIG_EXTRA_ENV_SETTINGS \ 1129 "myvar1=value1\0" \ 1130 "myvar2=value2\0" 1131 1132 Warning: This method is based on knowledge about the 1133 internal format how the environment is stored by the 1134 U-Boot code. This is NOT an official, expoerted 1135 interface! Although it is unlikely that this format 1136 will change soon, there is no guarantee either. 1137 You better know what you are doing here. 1138 1139 Note: overly (ab)use of the default environment is 1140 discouraged. Make sure to check other ways to preset 1141 the environment like the autoscript function or the 1142 boot command first. 1143 1144- Show boot progress 1145 CONFIG_SHOW_BOOT_PROGRESS 1146 1147 Defining this option allows to add some board- 1148 specific code (calling a user-provided function 1149 "show_boot_progress(int)") that enables you to show 1150 the system's boot progress on some display (for 1151 example, some LED's) on your board. At the moment, 1152 the following checkpoints are implemented: 1153 1154 Arg Where When 1155 1 common/cmd_bootm.c before attempting to boot an image 1156 -1 common/cmd_bootm.c Image header has bad magic number 1157 2 common/cmd_bootm.c Image header has correct magic number 1158 -2 common/cmd_bootm.c Image header has bad checksum 1159 3 common/cmd_bootm.c Image header has correct checksum 1160 -3 common/cmd_bootm.c Image data has bad checksum 1161 4 common/cmd_bootm.c Image data has correct checksum 1162 -4 common/cmd_bootm.c Image is for unsupported architecture 1163 5 common/cmd_bootm.c Architecture check OK 1164 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1165 6 common/cmd_bootm.c Image Type check OK 1166 -6 common/cmd_bootm.c gunzip uncompression error 1167 -7 common/cmd_bootm.c Unimplemented compression type 1168 7 common/cmd_bootm.c Uncompression OK 1169 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1170 8 common/cmd_bootm.c Image Type check OK 1171 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1172 9 common/cmd_bootm.c Start initial ramdisk verification 1173 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1174 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1175 10 common/cmd_bootm.c Ramdisk header is OK 1176 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1177 11 common/cmd_bootm.c Ramdisk data has correct checksum 1178 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1179 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1180 13 common/cmd_bootm.c Start multifile image verification 1181 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1182 15 common/cmd_bootm.c All preparation done, transferring control to OS 1183 1184 -1 common/cmd_doc.c Bad usage of "doc" command 1185 -1 common/cmd_doc.c No boot device 1186 -1 common/cmd_doc.c Unknown Chip ID on boot device 1187 -1 common/cmd_doc.c Read Error on boot device 1188 -1 common/cmd_doc.c Image header has bad magic number 1189 1190 -1 common/cmd_ide.c Bad usage of "ide" command 1191 -1 common/cmd_ide.c No boot device 1192 -1 common/cmd_ide.c Unknown boot device 1193 -1 common/cmd_ide.c Unknown partition table 1194 -1 common/cmd_ide.c Invalid partition type 1195 -1 common/cmd_ide.c Read Error on boot device 1196 -1 common/cmd_ide.c Image header has bad magic number 1197 1198 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1199 1200 1201Modem Support: 1202-------------- 1203 1204[so far only for SMDK2400 board] 1205 1206- Modem support endable: 1207 CONFIG_MODEM_SUPPORT 1208 1209- RTS/CTS Flow control enable: 1210 CONFIG_HWFLOW 1211 1212- Modem debug support: 1213 CONFIG_MODEM_SUPPORT_DEBUG 1214 1215 Enables debugging stuff (char screen[1024], dbg()) 1216 for modem support. Useful only with BDI2000. 1217 1218- General: 1219 1220 In the target system modem support is enabled when a 1221 specific key (key combination) is pressed during 1222 power-on. Otherwise U-Boot will boot normally 1223 (autoboot). The key_pressed() fuction is called from 1224 board_init(). Currently key_pressed() is a dummy 1225 function, returning 1 and thus enabling modem 1226 initialization. 1227 1228 If there are no modem init strings in the 1229 environment, U-Boot proceed to autoboot; the 1230 previous output (banner, info printfs) will be 1231 supressed, though. 1232 1233 See also: doc/README.Modem 1234 1235 1236 1237 1238Configuration Settings: 1239----------------------- 1240 1241- CFG_LONGHELP: Defined when you want long help messages included; 1242 undefine this when you're short of memory. 1243 1244- CFG_PROMPT: This is what U-Boot prints on the console to 1245 prompt for user input. 1246 1247- CFG_CBSIZE: Buffer size for input from the Console 1248 1249- CFG_PBSIZE: Buffer size for Console output 1250 1251- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1252 1253- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1254 the application (usually a Linux kernel) when it is 1255 booted 1256 1257- CFG_BAUDRATE_TABLE: 1258 List of legal baudrate settings for this board. 1259 1260- CFG_CONSOLE_INFO_QUIET 1261 Suppress display of console information at boot. 1262 1263- CFG_CONSOLE_IS_IN_ENV 1264 If the board specific function 1265 extern int overwrite_console (void); 1266 returns 1, the stdin, stderr and stdout are switched to the 1267 serial port, else the settings in the environment are used. 1268 1269- CFG_CONSOLE_OVERWRITE_ROUTINE 1270 Enable the call to overwrite_console(). 1271 1272- CFG_CONSOLE_ENV_OVERWRITE 1273 Enable overwrite of previous console environment settings. 1274 1275- CFG_MEMTEST_START, CFG_MEMTEST_END: 1276 Begin and End addresses of the area used by the 1277 simple memory test. 1278 1279- CFG_ALT_MEMTEST: 1280 Enable an alternate, more extensive memory test. 1281 1282- CFG_TFTP_LOADADDR: 1283 Default load address for network file downloads 1284 1285- CFG_LOADS_BAUD_CHANGE: 1286 Enable temporary baudrate change while serial download 1287 1288- CFG_SDRAM_BASE: 1289 Physical start address of SDRAM. _Must_ be 0 here. 1290 1291- CFG_MBIO_BASE: 1292 Physical start address of Motherboard I/O (if using a 1293 Cogent motherboard) 1294 1295- CFG_FLASH_BASE: 1296 Physical start address of Flash memory. 1297 1298- CFG_MONITOR_BASE: 1299 Physical start address of boot monitor code (set by 1300 make config files to be same as the text base address 1301 (TEXT_BASE) used when linking) - same as 1302 CFG_FLASH_BASE when booting from flash. 1303 1304- CFG_MONITOR_LEN: 1305 Size of memory reserved for monitor code 1306 1307- CFG_MALLOC_LEN: 1308 Size of DRAM reserved for malloc() use. 1309 1310- CFG_BOOTMAPSZ: 1311 Maximum size of memory mapped by the startup code of 1312 the Linux kernel; all data that must be processed by 1313 the Linux kernel (bd_info, boot arguments, eventually 1314 initrd image) must be put below this limit. 1315 1316- CFG_MAX_FLASH_BANKS: 1317 Max number of Flash memory banks 1318 1319- CFG_MAX_FLASH_SECT: 1320 Max number of sectors on a Flash chip 1321 1322- CFG_FLASH_ERASE_TOUT: 1323 Timeout for Flash erase operations (in ms) 1324 1325- CFG_FLASH_WRITE_TOUT: 1326 Timeout for Flash write operations (in ms) 1327 1328- CFG_DIRECT_FLASH_TFTP: 1329 1330 Enable TFTP transfers directly to flash memory; 1331 without this option such a download has to be 1332 performed in two steps: (1) download to RAM, and (2) 1333 copy from RAM to flash. 1334 1335 The two-step approach is usually more reliable, since 1336 you can check if the download worked before you erase 1337 the flash, but in some situations (when sytem RAM is 1338 too limited to allow for a tempory copy of the 1339 downloaded image) this option may be very useful. 1340 1341- CFG_FLASH_CFI: 1342 Define if the flash driver uses extra elements in the 1343 common flash structure for storing flash geometry 1344 1345The following definitions that deal with the placement and management 1346of environment data (variable area); in general, we support the 1347following configurations: 1348 1349- CFG_ENV_IS_IN_FLASH: 1350 1351 Define this if the environment is in flash memory. 1352 1353 a) The environment occupies one whole flash sector, which is 1354 "embedded" in the text segment with the U-Boot code. This 1355 happens usually with "bottom boot sector" or "top boot 1356 sector" type flash chips, which have several smaller 1357 sectors at the start or the end. For instance, such a 1358 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1359 such a case you would place the environment in one of the 1360 4 kB sectors - with U-Boot code before and after it. With 1361 "top boot sector" type flash chips, you would put the 1362 environment in one of the last sectors, leaving a gap 1363 between U-Boot and the environment. 1364 1365 - CFG_ENV_OFFSET: 1366 1367 Offset of environment data (variable area) to the 1368 beginning of flash memory; for instance, with bottom boot 1369 type flash chips the second sector can be used: the offset 1370 for this sector is given here. 1371 1372 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1373 1374 - CFG_ENV_ADDR: 1375 1376 This is just another way to specify the start address of 1377 the flash sector containing the environment (instead of 1378 CFG_ENV_OFFSET). 1379 1380 - CFG_ENV_SECT_SIZE: 1381 1382 Size of the sector containing the environment. 1383 1384 1385 b) Sometimes flash chips have few, equal sized, BIG sectors. 1386 In such a case you don't want to spend a whole sector for 1387 the environment. 1388 1389 - CFG_ENV_SIZE: 1390 1391 If you use this in combination with CFG_ENV_IS_IN_FLASH 1392 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1393 of this flash sector for the environment. This saves 1394 memory for the RAM copy of the environment. 1395 1396 It may also save flash memory if you decide to use this 1397 when your environment is "embedded" within U-Boot code, 1398 since then the remainder of the flash sector could be used 1399 for U-Boot code. It should be pointed out that this is 1400 STRONGLY DISCOURAGED from a robustness point of view: 1401 updating the environment in flash makes it always 1402 necessary to erase the WHOLE sector. If something goes 1403 wrong before the contents has been restored from a copy in 1404 RAM, your target system will be dead. 1405 1406 - CFG_ENV_ADDR_REDUND 1407 CFG_ENV_SIZE_REDUND 1408 1409 These settings describe a second storage area used to hold 1410 a redundand copy of the environment data, so that there is 1411 a valid backup copy in case there is a power failur during 1412 a "saveenv" operation. 1413 1414BE CAREFUL! Any changes to the flash layout, and some changes to the 1415source code will make it necessary to adapt <board>/u-boot.lds* 1416accordingly! 1417 1418 1419- CFG_ENV_IS_IN_NVRAM: 1420 1421 Define this if you have some non-volatile memory device 1422 (NVRAM, battery buffered SRAM) which you want to use for the 1423 environment. 1424 1425 - CFG_ENV_ADDR: 1426 - CFG_ENV_SIZE: 1427 1428 These two #defines are used to determin the memory area you 1429 want to use for environment. It is assumed that this memory 1430 can just be read and written to, without any special 1431 provision. 1432 1433BE CAREFUL! The first access to the environment happens quite early 1434in U-Boot initalization (when we try to get the setting of for the 1435console baudrate). You *MUST* have mappend your NVRAM area then, or 1436U-Boot will hang. 1437 1438Please note that even with NVRAM we still use a copy of the 1439environment in RAM: we could work on NVRAM directly, but we want to 1440keep settings there always unmodified except somebody uses "saveenv" 1441to save the current settings. 1442 1443 1444- CFG_ENV_IS_IN_EEPROM: 1445 1446 Use this if you have an EEPROM or similar serial access 1447 device and a driver for it. 1448 1449 - CFG_ENV_OFFSET: 1450 - CFG_ENV_SIZE: 1451 1452 These two #defines specify the offset and size of the 1453 environment area within the total memory of your EEPROM. 1454 1455 - CFG_I2C_EEPROM_ADDR: 1456 If defined, specified the chip address of the EEPROM device. 1457 The default address is zero. 1458 1459 - CFG_EEPROM_PAGE_WRITE_BITS: 1460 If defined, the number of bits used to address bytes in a 1461 single page in the EEPROM device. A 64 byte page, for example 1462 would require six bits. 1463 1464 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1465 If defined, the number of milliseconds to delay between 1466 page writes. The default is zero milliseconds. 1467 1468 - CFG_I2C_EEPROM_ADDR_LEN: 1469 The length in bytes of the EEPROM memory array address. Note 1470 that this is NOT the chip address length! 1471 1472 - CFG_EEPROM_SIZE: 1473 The size in bytes of the EEPROM device. 1474 1475 - CFG_I2C_EEPROM_ADDR: 1476 If defined, specified the chip address of the EEPROM device. 1477 The default address is zero. 1478 1479 - CFG_EEPROM_PAGE_WRITE_BITS: 1480 If defined, the number of bits used to address bytes in a 1481 single page in the EEPROM device. A 64 byte page, for example 1482 would require six bits. 1483 1484 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1485 If defined, the number of milliseconds to delay between 1486 page writes. The default is zero milliseconds. 1487 1488 - CFG_I2C_EEPROM_ADDR_LEN: 1489 The length in bytes of the EEPROM memory array address. Note 1490 that this is NOT the chip address length! 1491 1492 - CFG_EEPROM_SIZE: 1493 The size in bytes of the EEPROM device. 1494 1495- CFG_SPI_INIT_OFFSET 1496 1497 Defines offset to the initial SPI buffer area in DPRAM. The 1498 area is used at an early stage (ROM part) if the environment 1499 is configured to reside in the SPI EEPROM: We need a 520 byte 1500 scratch DPRAM area. It is used between the two initialization 1501 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1502 to be a good choice since it makes it far enough from the 1503 start of the data area as well as from the stack pointer. 1504 1505Please note that the environment is read-only as long as the monitor 1506has been relocated to RAM and a RAM copy of the environment has been 1507created; also, when using EEPROM you will have to use getenv_r() 1508until then to read environment variables. 1509 1510The environment is now protected by a CRC32 checksum. Before the 1511monitor is relocated into RAM, as a result of a bad CRC you will be 1512working with the compiled-in default environment - *silently*!!! 1513[This is necessary, because the first environment variable we need is 1514the "baudrate" setting for the console - if we have a bad CRC, we 1515don't have any device yet where we could complain.] 1516 1517Note: once the monitor has been relocated, then it will complain if 1518the default environment is used; a new CRC is computed as soon as you 1519use the "setenv" command to modify / delete / add any environment 1520variable [even when you try to delete a non-existing variable!]. 1521 1522Note2: you must edit your u-boot.lds file to reflect this 1523configuration. 1524 1525 1526Many of the options are named exactly as the corresponding Linux 1527kernel configuration options. The intention is to make it easier to 1528build a config tool - later. 1529 1530Low Level (hardware related) configuration options: 1531 1532- CFG_CACHELINE_SIZE: 1533 Cache Line Size of the CPU. 1534 1535- CFG_DEFAULT_IMMR: 1536 Default address of the IMMR after system reset. 1537 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1538 to be able to adjust the position of the IMMR 1539 register after a reset. 1540 1541- CFG_IMMR: Physical address of the Internal Memory Mapped 1542 Register; DO NOT CHANGE! (11-4) 1543 [MPC8xx systems only] 1544 1545- CFG_INIT_RAM_ADDR: 1546 1547 Start address of memory area tha can be used for 1548 initial data and stack; please note that this must be 1549 writable memory that is working WITHOUT special 1550 initialization, i. e. you CANNOT use normal RAM which 1551 will become available only after programming the 1552 memory controller and running certain initialization 1553 sequences. 1554 1555 U-Boot uses the following memory types: 1556 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1557 - MPC824X: data cache 1558 - PPC4xx: data cache 1559 1560- CFG_INIT_DATA_OFFSET: 1561 1562 Offset of the initial data structure in the memory 1563 area defined by CFG_INIT_RAM_ADDR. Usually 1564 CFG_INIT_DATA_OFFSET is chosen such that the initial 1565 data is located at the end of the available space 1566 (sometimes written as (CFG_INIT_RAM_END - 1567 CFG_INIT_DATA_SIZE), and the initial stack is just 1568 below that area (growing from (CFG_INIT_RAM_ADDR + 1569 CFG_INIT_DATA_OFFSET) downward. 1570 1571 Note: 1572 On the MPC824X (or other systems that use the data 1573 cache for initial memory) the address chosen for 1574 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1575 point to an otherwise UNUSED address space between 1576 the top of RAM and the start of the PCI space. 1577 1578- CFG_SIUMCR: SIU Module Configuration (11-6) 1579 1580- CFG_SYPCR: System Protection Control (11-9) 1581 1582- CFG_TBSCR: Time Base Status and Control (11-26) 1583 1584- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1585 1586- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1587 1588- CFG_SCCR: System Clock and reset Control Register (15-27) 1589 1590- CFG_OR_TIMING_SDRAM: 1591 SDRAM timing 1592 1593- CFG_MAMR_PTA: 1594 periodic timer for refresh 1595 1596- CFG_DER: Debug Event Register (37-47) 1597 1598- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1599 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1600 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1601 CFG_BR1_PRELIM: 1602 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1603 1604- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1605 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1606 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1607 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1608 1609- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1610 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1611 Machine Mode Register and Memory Periodic Timer 1612 Prescaler definitions (SDRAM timing) 1613 1614- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1615 enable I2C microcode relocation patch (MPC8xx); 1616 define relocation offset in DPRAM [DSP2] 1617 1618- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1619 enable SPI microcode relocation patch (MPC8xx); 1620 define relocation offset in DPRAM [SCC4] 1621 1622- CFG_USE_OSCCLK: 1623 Use OSCM clock mode on MBX8xx board. Be careful, 1624 wrong setting might damage your board. Read 1625 doc/README.MBX before setting this variable! 1626 1627Building the Software: 1628====================== 1629 1630Building U-Boot has been tested in native PPC environments (on a 1631PowerBook G3 running LinuxPPC 2000) and in cross environments 1632(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1633NetBSD 1.5 on x86). 1634 1635If you are not using a native PPC environment, it is assumed that you 1636have the GNU cross compiling tools available in your path and named 1637with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1638you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1639the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1640change it to: 1641 1642 CROSS_COMPILE = ppc_4xx- 1643 1644 1645U-Boot is intended to be simple to build. After installing the 1646sources you must configure U-Boot for one specific board type. This 1647is done by typing: 1648 1649 make NAME_config 1650 1651where "NAME_config" is the name of one of the existing 1652configurations; the following names are supported: 1653 1654 ADCIOP_config GTH_config TQM850L_config 1655 ADS860_config IP860_config TQM855L_config 1656 AR405_config IVML24_config TQM860L_config 1657 CANBT_config IVMS8_config WALNUT405_config 1658 CPCI405_config LANTEC_config cogent_common_config 1659 CPCIISER4_config MBX_config cogent_mpc8260_config 1660 CU824_config MBX860T_config cogent_mpc8xx_config 1661 ESTEEM192E_config RPXlite_config hermes_config 1662 ETX094_config RPXsuper_config hymod_config 1663 FADS823_config SM850_config lwmon_config 1664 FADS850SAR_config SPD823TS_config pcu_e_config 1665 FADS860T_config SXNI855T_config rsdproto_config 1666 FPS850L_config Sandpoint8240_config sbc8260_config 1667 GENIETV_config TQM823L_config PIP405_config 1668 GEN860T_config EBONY_config 1669 1670Note: for some board special configuration names may exist; check if 1671 additional information is available from the board vendor; for 1672 instance, the TQM8xxL systems run normally at 50 MHz and use a 1673 SCC for 10baseT ethernet; there are also systems with 80 MHz 1674 CPU clock, and an optional Fast Ethernet module is available 1675 for CPU's with FEC. You can select such additional "features" 1676 when chosing the configuration, i. e. 1677 1678 make TQM860L_config 1679 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1680 1681 make TQM860L_FEC_config 1682 - will configure for a TQM860L at 50MHz with FEC for ethernet 1683 1684 make TQM860L_80MHz_config 1685 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1686 interface 1687 1688 make TQM860L_FEC_80MHz_config 1689 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1690 1691 make TQM823L_LCD_config 1692 - will configure for a TQM823L with U-Boot console on LCD 1693 1694 make TQM823L_LCD_80MHz_config 1695 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1696 1697 etc. 1698 1699 1700 1701Finally, type "make all", and you should get some working U-Boot 1702images ready for downlod to / installation on your system: 1703 1704- "u-boot.bin" is a raw binary image 1705- "u-boot" is an image in ELF binary format 1706- "u-boot.srec" is in Motorola S-Record format 1707 1708 1709Please be aware that the Makefiles assume you are using GNU make, so 1710for instance on NetBSD you might need to use "gmake" instead of 1711native "make". 1712 1713 1714If the system board that you have is not listed, then you will need 1715to port U-Boot to your hardware platform. To do this, follow these 1716steps: 1717 17181. Add a new configuration option for your board to the toplevel 1719 "Makefile", using the existing entries as examples. 17202. Create a new directory to hold your board specific code. Add any 1721 files you need. 17223. If you're porting U-Boot to a new CPU, then also create a new 1723 directory to hold your CPU specific code. Add any files you need. 17244. Run "make config_name" with your new name. 17255. Type "make", and you should get a working "u-boot.srec" file 1726 to be installed on your target system. 1727 [Of course, this last step is much harder than it sounds.] 1728 1729 1730Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1731============================================================== 1732 1733If you have modified U-Boot sources (for instance added a new board 1734or support for new devices, a new CPU, etc.) you are expected to 1735provide feedback to the other developers. The feedback normally takes 1736the form of a "patch", i. e. a context diff against a certain (latest 1737official or latest in CVS) version of U-Boot sources. 1738 1739But before you submit such a patch, please verify that your modifi- 1740cation did not break existing code. At least make sure that *ALL* of 1741the supported boards compile WITHOUT ANY compiler warnings. To do so, 1742just run the "MAKEALL" script, which will configure and build U-Boot 1743for ALL supported system. Be warned, this will take a while. You can 1744select which (cross) compiler to use py passing a `CROSS_COMPILE' 1745environment variable to the script, i. e. to use the cross tools from 1746MontaVista's Hard Hat Linux you can type 1747 1748 CROSS_COMPILE=ppc_8xx- MAKEALL 1749 1750or to build on a native PowerPC system you can type 1751 1752 CROSS_COMPILE=' ' MAKEALL 1753 1754See also "U-Boot Porting Guide" below. 1755 1756 1757 1758Monitor Commands - Overview: 1759============================ 1760 1761go - start application at address 'addr' 1762run - run commands in an environment variable 1763bootm - boot application image from memory 1764bootp - boot image via network using BootP/TFTP protocol 1765tftpboot- boot image via network using TFTP protocol 1766 and env variables "ipaddr" and "serverip" 1767 (and eventually "gatewayip") 1768rarpboot- boot image via network using RARP/TFTP protocol 1769diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1770loads - load S-Record file over serial line 1771loadb - load binary file over serial line (kermit mode) 1772md - memory display 1773mm - memory modify (auto-incrementing) 1774nm - memory modify (constant address) 1775mw - memory write (fill) 1776cp - memory copy 1777cmp - memory compare 1778crc32 - checksum calculation 1779imd - i2c memory display 1780imm - i2c memory modify (auto-incrementing) 1781inm - i2c memory modify (constant address) 1782imw - i2c memory write (fill) 1783icrc32 - i2c checksum calculation 1784iprobe - probe to discover valid I2C chip addresses 1785iloop - infinite loop on address range 1786isdram - print SDRAM configuration information 1787sspi - SPI utility commands 1788base - print or set address offset 1789printenv- print environment variables 1790setenv - set environment variables 1791saveenv - save environment variables to persistent storage 1792protect - enable or disable FLASH write protection 1793erase - erase FLASH memory 1794flinfo - print FLASH memory information 1795bdinfo - print Board Info structure 1796iminfo - print header information for application image 1797coninfo - print console devices and informations 1798ide - IDE sub-system 1799loop - infinite loop on address range 1800mtest - simple RAM test 1801icache - enable or disable instruction cache 1802dcache - enable or disable data cache 1803reset - Perform RESET of the CPU 1804echo - echo args to console 1805version - print monitor version 1806help - print online help 1807? - alias for 'help' 1808 1809 1810Monitor Commands - Detailed Description: 1811======================================== 1812 1813TODO. 1814 1815For now: just type "help <command>". 1816 1817 1818Environment Variables: 1819====================== 1820 1821U-Boot supports user configuration using Environment Variables which 1822can be made persistent by saving to Flash memory. 1823 1824Environment Variables are set using "setenv", printed using 1825"printenv", and saved to Flash using "saveenv". Using "setenv" 1826without a value can be used to delete a variable from the 1827environment. As long as you don't save the environment you are 1828working with an in-memory copy. In case the Flash area containing the 1829environment is erased by accident, a default environment is provided. 1830 1831Some configuration options can be set using Environment Variables: 1832 1833 baudrate - see CONFIG_BAUDRATE 1834 1835 bootdelay - see CONFIG_BOOTDELAY 1836 1837 bootcmd - see CONFIG_BOOTCOMMAND 1838 1839 bootargs - Boot arguments when booting an RTOS image 1840 1841 bootfile - Name of the image to load with TFTP 1842 1843 autoload - if set to "no" (any string beginning with 'n'), 1844 "bootp" will just load perform a lookup of the 1845 configuration from the BOOTP server, but not try to 1846 load any image using TFTP 1847 1848 autostart - if set to "yes", an image loaded using the "bootp", 1849 "rarpboot", "tftpboot" or "diskboot" commands will 1850 be automatically started (by internally calling 1851 "bootm") 1852 1853 initrd_high - restrict positioning of initrd images: 1854 If this variable is not set, initrd images will be 1855 copied to the highest possible address in RAM; this 1856 is usually what you want since it allows for 1857 maximum initrd size. If for some reason you want to 1858 make sure that the initrd image is loaded below the 1859 CFG_BOOTMAPSZ limit, you can set this environment 1860 variable to a value of "no" or "off" or "0". 1861 Alternatively, you can set it to a maximum upper 1862 address to use (U-Boot will still check that it 1863 does not overwrite the U-Boot stack and data). 1864 1865 For instance, when you have a system with 16 MB 1866 RAM, and want to reseve 4 MB from use by Linux, 1867 you can do this by adding "mem=12M" to the value of 1868 the "bootargs" variable. However, now you must make 1869 sure, that the initrd image is placed in the first 1870 12 MB as well - this can be done with 1871 1872 setenv initrd_high 00c00000 1873 1874 ipaddr - IP address; needed for tftpboot command 1875 1876 loadaddr - Default load address for commands like "bootp", 1877 "rarpboot", "tftpboot" or "diskboot" 1878 1879 loads_echo - see CONFIG_LOADS_ECHO 1880 1881 serverip - TFTP server IP address; needed for tftpboot command 1882 1883 bootretry - see CONFIG_BOOT_RETRY_TIME 1884 1885 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1886 1887 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1888 1889 1890The following environment variables may be used and automatically 1891updated by the network boot commands ("bootp" and "rarpboot"), 1892depending the information provided by your boot server: 1893 1894 bootfile - see above 1895 dnsip - IP address of your Domain Name Server 1896 gatewayip - IP address of the Gateway (Router) to use 1897 hostname - Target hostname 1898 ipaddr - see above 1899 netmask - Subnet Mask 1900 rootpath - Pathname of the root filesystem on the NFS server 1901 serverip - see above 1902 1903 1904There are two special Environment Variables: 1905 1906 serial# - contains hardware identification information such 1907 as type string and/or serial number 1908 ethaddr - Ethernet address 1909 1910These variables can be set only once (usually during manufacturing of 1911the board). U-Boot refuses to delete or overwrite these variables 1912once they have been set once. 1913 1914 1915Please note that changes to some configuration parameters may take 1916only effect after the next boot (yes, that's just like Windoze :-). 1917 1918 1919Note for Redundant Ethernet Interfaces: 1920======================================= 1921 1922Some boards come with redundand ethernet interfaces; U-Boot supports 1923such configurations and is capable of automatic selection of a 1924"working" interface when needed. MAC assignemnt works as follows: 1925 1926Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1927MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1928"eth1addr" (=>eth1), "eth2addr", ... 1929 1930If the network interface stores some valid MAC address (for instance 1931in SROM), this is used as default address if there is NO correspon- 1932ding setting in the environment; if the corresponding environment 1933variable is set, this overrides the settings in the card; that means: 1934 1935o If the SROM has a valid MAC address, and there is no address in the 1936 environment, the SROM's address is used. 1937 1938o If there is no valid address in the SROM, and a definition in the 1939 environment exists, then the value from the environment variable is 1940 used. 1941 1942o If both the SROM and the environment contain a MAC address, and 1943 both addresses are the same, this MAC address is used. 1944 1945o If both the SROM and the environment contain a MAC address, and the 1946 addresses differ, the value from the environment is used and a 1947 warning is printed. 1948 1949o If neither SROM nor the environment contain a MAC address, an error 1950 is raised. 1951 1952 1953 1954Image Formats: 1955============== 1956 1957The "boot" commands of this monitor operate on "image" files which 1958can be basicly anything, preceeded by a special header; see the 1959definitions in include/image.h for details; basicly, the header 1960defines the following image properties: 1961 1962* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 1963 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 1964 LynxOS, pSOS, QNX; 1965 Currently supported: Linux, NetBSD, VxWorks, QNX). 1966* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 1967 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 1968 Currently supported: PowerPC). 1969* Compression Type (Provisions for uncompressed, gzip, bzip2; 1970 Currently supported: uncompressed, gzip). 1971* Load Address 1972* Entry Point 1973* Image Name 1974* Image Timestamp 1975 1976The header is marked by a special Magic Number, and both the header 1977and the data portions of the image are secured against corruption by 1978CRC32 checksums. 1979 1980 1981Linux Support: 1982============== 1983 1984Although U-Boot should support any OS or standalone application 1985easily, Linux has always been in the focus during the design of 1986U-Boot. 1987 1988U-Boot includes many features that so far have been part of some 1989special "boot loader" code within the Linux kernel. Also, any 1990"initrd" images to be used are no longer part of one big Linux image; 1991instead, kernel and "initrd" are separate images. This implementation 1992serves serveral purposes: 1993 1994- the same features can be used for other OS or standalone 1995 applications (for instance: using compressed images to reduce the 1996 Flash memory footprint) 1997 1998- it becomes much easier to port new Linux kernel versions because 1999 lots of low-level, hardware dependend stuff are done by U-Boot 2000 2001- the same Linux kernel image can now be used with different "initrd" 2002 images; of course this also means that different kernel images can 2003 be run with the same "initrd". This makes testing easier (you don't 2004 have to build a new "zImage.initrd" Linux image when you just 2005 change a file in your "initrd"). Also, a field-upgrade of the 2006 software is easier now. 2007 2008 2009Linux HOWTO: 2010============ 2011 2012Porting Linux to U-Boot based systems: 2013--------------------------------------- 2014 2015U-Boot cannot save you from doing all the necessary modifications to 2016configure the Linux device drivers for use with your target hardware 2017(no, we don't intend to provide a full virtual machine interface to 2018Linux :-). 2019 2020But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2021 2022Just make sure your machine specific header file (for instance 2023include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2024Information structure as we define in include/u-boot.h, and make 2025sure that your definition of IMAP_ADDR uses the same value as your 2026U-Boot configuration in CFG_IMMR. 2027 2028 2029Configuring the Linux kernel: 2030----------------------------- 2031 2032No specific requirements for U-Boot. Make sure you have some root 2033device (initial ramdisk, NFS) for your target system. 2034 2035 2036Building a Linux Image: 2037----------------------- 2038 2039With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2040not used. If you use recent kernel source, a new build target 2041"uImage" will exist which automatically builds an image usable by 2042U-Boot. Most older kernels also have support for a "pImage" target, 2043which was introduced for our predecessor project PPCBoot and uses a 2044100% compatible format. 2045 2046Example: 2047 2048 make TQM850L_config 2049 make oldconfig 2050 make dep 2051 make uImage 2052 2053The "uImage" build target uses a special tool (in 'tools/mkimage') to 2054encapsulate a compressed Linux kernel image with header information, 2055CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2056 2057* build a standard "vmlinux" kernel image (in ELF binary format): 2058 2059* convert the kernel into a raw binary image: 2060 2061 ${CROSS_COMPILE}-objcopy -O binary \ 2062 -R .note -R .comment \ 2063 -S vmlinux linux.bin 2064 2065* compress the binary image: 2066 2067 gzip -9 linux.bin 2068 2069* package compressed binary image for U-Boot: 2070 2071 mkimage -A ppc -O linux -T kernel -C gzip \ 2072 -a 0 -e 0 -n "Linux Kernel Image" \ 2073 -d linux.bin.gz uImage 2074 2075 2076The "mkimage" tool can also be used to create ramdisk images for use 2077with U-Boot, either separated from the Linux kernel image, or 2078combined into one file. "mkimage" encapsulates the images with a 64 2079byte header containing information about target architecture, 2080operating system, image type, compression method, entry points, time 2081stamp, CRC32 checksums, etc. 2082 2083"mkimage" can be called in two ways: to verify existing images and 2084print the header information, or to build new images. 2085 2086In the first form (with "-l" option) mkimage lists the information 2087contained in the header of an existing U-Boot image; this includes 2088checksum verification: 2089 2090 tools/mkimage -l image 2091 -l ==> list image header information 2092 2093The second form (with "-d" option) is used to build a U-Boot image 2094from a "data file" which is used as image payload: 2095 2096 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2097 -n name -d data_file image 2098 -A ==> set architecture to 'arch' 2099 -O ==> set operating system to 'os' 2100 -T ==> set image type to 'type' 2101 -C ==> set compression type 'comp' 2102 -a ==> set load address to 'addr' (hex) 2103 -e ==> set entry point to 'ep' (hex) 2104 -n ==> set image name to 'name' 2105 -d ==> use image data from 'datafile' 2106 2107Right now, all Linux kernels use the same load address (0x00000000), 2108but the entry point address depends on the kernel version: 2109 2110- 2.2.x kernels have the entry point at 0x0000000C, 2111- 2.3.x and later kernels have the entry point at 0x00000000. 2112 2113So a typical call to build a U-Boot image would read: 2114 2115 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2116 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2117 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2118 > examples/uImage.TQM850L 2119 Image Name: 2.4.4 kernel for TQM850L 2120 Created: Wed Jul 19 02:34:59 2000 2121 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2122 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2123 Load Address: 0x00000000 2124 Entry Point: 0x00000000 2125 2126To verify the contents of the image (or check for corruption): 2127 2128 -> tools/mkimage -l examples/uImage.TQM850L 2129 Image Name: 2.4.4 kernel for TQM850L 2130 Created: Wed Jul 19 02:34:59 2000 2131 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2132 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2133 Load Address: 0x00000000 2134 Entry Point: 0x00000000 2135 2136NOTE: for embedded systems where boot time is critical you can trade 2137speed for memory and install an UNCOMPRESSED image instead: this 2138needs more space in Flash, but boots much faster since it does not 2139need to be uncompressed: 2140 2141 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2142 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2143 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2144 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2145 > examples/uImage.TQM850L-uncompressed 2146 Image Name: 2.4.4 kernel for TQM850L 2147 Created: Wed Jul 19 02:34:59 2000 2148 Image Type: PowerPC Linux Kernel Image (uncompressed) 2149 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2150 Load Address: 0x00000000 2151 Entry Point: 0x00000000 2152 2153 2154Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2155when your kernel is intended to use an initial ramdisk: 2156 2157 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2158 > -A ppc -O linux -T ramdisk -C gzip \ 2159 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2160 Image Name: Simple Ramdisk Image 2161 Created: Wed Jan 12 14:01:50 2000 2162 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2163 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2164 Load Address: 0x00000000 2165 Entry Point: 0x00000000 2166 2167 2168Installing a Linux Image: 2169------------------------- 2170 2171To downloading a U-Boot image over the serial (console) interface, 2172you must convert the image to S-Record format: 2173 2174 objcopy -I binary -O srec examples/image examples/image.srec 2175 2176The 'objcopy' does not understand the information in the U-Boot 2177image header, so the resulting S-Record file will be relative to 2178address 0x00000000. To load it to a given address, you need to 2179specify the target address as 'offset' parameter with the 'loads' 2180command. 2181 2182Example: install the image to address 0x40100000 (which on the 2183TQM8xxL is in the first Flash bank): 2184 2185 => erase 40100000 401FFFFF 2186 2187 .......... done 2188 Erased 8 sectors 2189 2190 => loads 40100000 2191 ## Ready for S-Record download ... 2192 ~>examples/image.srec 2193 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2194 ... 2195 15989 15990 15991 15992 2196 [file transfer complete] 2197 [connected] 2198 ## Start Addr = 0x00000000 2199 2200 2201You can check the success of the download using the 'iminfo' command; 2202this includes a checksum verification so you can be sure no data 2203corruption happened: 2204 2205 => imi 40100000 2206 2207 ## Checking Image at 40100000 ... 2208 Image Name: 2.2.13 for initrd on TQM850L 2209 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2210 Data Size: 335725 Bytes = 327 kB = 0 MB 2211 Load Address: 00000000 2212 Entry Point: 0000000c 2213 Verifying Checksum ... OK 2214 2215 2216 2217Boot Linux: 2218----------- 2219 2220The "bootm" command is used to boot an application that is stored in 2221memory (RAM or Flash). In case of a Linux kernel image, the contents 2222of the "bootargs" environment variable is passed to the kernel as 2223parameters. You can check and modify this variable using the 2224"printenv" and "setenv" commands: 2225 2226 2227 => printenv bootargs 2228 bootargs=root=/dev/ram 2229 2230 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2231 2232 => printenv bootargs 2233 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2234 2235 => bootm 40020000 2236 ## Booting Linux kernel at 40020000 ... 2237 Image Name: 2.2.13 for NFS on TQM850L 2238 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2239 Data Size: 381681 Bytes = 372 kB = 0 MB 2240 Load Address: 00000000 2241 Entry Point: 0000000c 2242 Verifying Checksum ... OK 2243 Uncompressing Kernel Image ... OK 2244 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 2245 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2246 time_init: decrementer frequency = 187500000/60 2247 Calibrating delay loop... 49.77 BogoMIPS 2248 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2249 ... 2250 2251If you want to boot a Linux kernel with initial ram disk, you pass 2252the memory addreses of both the kernel and the initrd image (PPBCOOT 2253format!) to the "bootm" command: 2254 2255 => imi 40100000 40200000 2256 2257 ## Checking Image at 40100000 ... 2258 Image Name: 2.2.13 for initrd on TQM850L 2259 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2260 Data Size: 335725 Bytes = 327 kB = 0 MB 2261 Load Address: 00000000 2262 Entry Point: 0000000c 2263 Verifying Checksum ... OK 2264 2265 ## Checking Image at 40200000 ... 2266 Image Name: Simple Ramdisk Image 2267 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2268 Data Size: 566530 Bytes = 553 kB = 0 MB 2269 Load Address: 00000000 2270 Entry Point: 00000000 2271 Verifying Checksum ... OK 2272 2273 => bootm 40100000 40200000 2274 ## Booting Linux kernel at 40100000 ... 2275 Image Name: 2.2.13 for initrd on TQM850L 2276 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2277 Data Size: 335725 Bytes = 327 kB = 0 MB 2278 Load Address: 00000000 2279 Entry Point: 0000000c 2280 Verifying Checksum ... OK 2281 Uncompressing Kernel Image ... OK 2282 ## Loading RAMDisk Image at 40200000 ... 2283 Image Name: Simple Ramdisk Image 2284 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2285 Data Size: 566530 Bytes = 553 kB = 0 MB 2286 Load Address: 00000000 2287 Entry Point: 00000000 2288 Verifying Checksum ... OK 2289 Loading Ramdisk ... OK 2290 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 2291 Boot arguments: root=/dev/ram 2292 time_init: decrementer frequency = 187500000/60 2293 Calibrating delay loop... 49.77 BogoMIPS 2294 ... 2295 RAMDISK: Compressed image found at block 0 2296 VFS: Mounted root (ext2 filesystem). 2297 2298 bash# 2299 2300 2301Standalone HOWTO: 2302================= 2303 2304One of the features of U-Boot is that you can dynamically load and 2305run "standalone" applications, which can use some resources of 2306U-Boot like console I/O functions or interrupt services. 2307 2308Two simple examples are included with the sources: 2309 2310"Hello World" Demo: 2311------------------- 2312 2313'examples/hello_world.c' contains a small "Hello World" Demo 2314application; it is automatically compiled when you build U-Boot. 2315It's configured to run at address 0x00040004, so you can play with it 2316like that: 2317 2318 => loads 2319 ## Ready for S-Record download ... 2320 ~>examples/hello_world.srec 2321 1 2 3 4 5 6 7 8 9 10 11 ... 2322 [file transfer complete] 2323 [connected] 2324 ## Start Addr = 0x00040004 2325 2326 => go 40004 Hello World! This is a test. 2327 ## Starting application at 0x00040004 ... 2328 Hello World 2329 argc = 7 2330 argv[0] = "40004" 2331 argv[1] = "Hello" 2332 argv[2] = "World!" 2333 argv[3] = "This" 2334 argv[4] = "is" 2335 argv[5] = "a" 2336 argv[6] = "test." 2337 argv[7] = "<NULL>" 2338 Hit any key to exit ... 2339 2340 ## Application terminated, rc = 0x0 2341 2342Another example, which demonstrates how to register a CPM interrupt 2343handler with the U-Boot code, can be found in 'examples/timer.c'. 2344Here, a CPM timer is set up to generate an interrupt every second. 2345The interrupt service routine is trivial, just printing a '.' 2346character, but this is just a demo program. The application can be 2347controlled by the following keys: 2348 2349 ? - print current values og the CPM Timer registers 2350 b - enable interrupts and start timer 2351 e - stop timer and disable interrupts 2352 q - quit application 2353 2354 => loads 2355 ## Ready for S-Record download ... 2356 ~>examples/timer.srec 2357 1 2 3 4 5 6 7 8 9 10 11 ... 2358 [file transfer complete] 2359 [connected] 2360 ## Start Addr = 0x00040004 2361 2362 => go 40004 2363 ## Starting application at 0x00040004 ... 2364 TIMERS=0xfff00980 2365 Using timer 1 2366 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2367 2368Hit 'b': 2369 [q, b, e, ?] Set interval 1000000 us 2370 Enabling timer 2371Hit '?': 2372 [q, b, e, ?] ........ 2373 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2374Hit '?': 2375 [q, b, e, ?] . 2376 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2377Hit '?': 2378 [q, b, e, ?] . 2379 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2380Hit '?': 2381 [q, b, e, ?] . 2382 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2383Hit 'e': 2384 [q, b, e, ?] ...Stopping timer 2385Hit 'q': 2386 [q, b, e, ?] ## Application terminated, rc = 0x0 2387 2388 2389NetBSD Notes: 2390============= 2391 2392Starting at version 0.9.2, U-Boot supports NetBSD both as host 2393(build U-Boot) and target system (boots NetBSD/mpc8xx). 2394 2395Building requires a cross environment; it is known to work on 2396NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2397need gmake since the Makefiles are not compatible with BSD make). 2398Note that the cross-powerpc package does not install include files; 2399attempting to build U-Boot will fail because <machine/ansi.h> is 2400missing. This file has to be installed and patched manually: 2401 2402 # cd /usr/pkg/cross/powerpc-netbsd/include 2403 # mkdir powerpc 2404 # ln -s powerpc machine 2405 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2406 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2407 2408Native builds *don't* work due to incompatibilities between native 2409and U-Boot include files. 2410 2411Booting assumes that (the first part of) the image booted is a 2412stage-2 loader which in turn loads and then invokes the kernel 2413proper. Loader sources will eventually appear in the NetBSD source 2414tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2415meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2416details. 2417 2418 2419Implementation Internals: 2420========================= 2421 2422The following is not intended to be a complete description of every 2423implementation detail. However, it should help to understand the 2424inner workings of U-Boot and make it easier to port it to custom 2425hardware. 2426 2427 2428Initial Stack, Global Data: 2429--------------------------- 2430 2431The implementation of U-Boot is complicated by the fact that U-Boot 2432starts running out of ROM (flash memory), usually without access to 2433system RAM (because the memory controller is not initialized yet). 2434This means that we don't have writable Data or BSS segments, and BSS 2435is not initialized as zero. To be able to get a C environment working 2436at all, we have to allocate at least a minimal stack. Implementation 2437options for this are defined and restricted by the CPU used: Some CPU 2438models provide on-chip memory (like the IMMR area on MPC8xx and 2439MPC826x processors), on others (parts of) the data cache can be 2440locked as (mis-) used as memory, etc. 2441 2442It is essential to remember this, since it has some impact on the C 2443code for the initialization procedures: 2444 2445* Initialized global data (data segment) is read-only. Do not attempt 2446 to write it. 2447 2448* Do not use any unitialized global data (or implicitely initialized 2449 as zero data - BSS segment) at all - this is undefined, initiali- 2450 zation is performed later (when relocationg to RAM). 2451 2452* Stack space is very limited. Avoid big data buffers or things like 2453 that. 2454 2455Having only the stack as writable memory limits means we cannot use 2456normal global data to share information beween the code. But it 2457turned out that the implementation of U-Boot can be greatly 2458simplified by making a global data structure (gd_t) available to all 2459functions. We could pass a pointer to this data as argument to _all_ 2460functions, but this would bloat the code. Instead we use a feature of 2461the GCC compiler (Global Register Variables) to share the data: we 2462place a pointer (gd) to the global data into a register which we 2463reserve for this purpose. 2464 2465When chosing a register for such a purpose we are restricted by the 2466relevant (E)ABI specifications for the current architecture, and by 2467GCC's implementation. 2468 2469For PowerPC, the following registers have specific use: 2470 R1: stack pointer 2471 R2: TOC pointer 2472 R3-R4: parameter passing and return values 2473 R5-R10: parameter passing 2474 R13: small data area pointer 2475 R30: GOT pointer 2476 R31: frame pointer 2477 2478 (U-Boot also uses R14 as internal GOT pointer.) 2479 2480 ==> U-Boot will use R29 to hold a pointer to the global data 2481 2482 Note: on PPC, we could use a static initializer (since the 2483 address of the global data structure is known at compile time), 2484 but it turned out that reserving a register results in somewhat 2485 smaller code - although the code savings are not that big (on 2486 average for all boards 752 bytes for the whole U-Boot image, 2487 624 text + 127 data). 2488 2489On ARM, the following registers are used: 2490 2491 R0: function argument word/integer result 2492 R1-R3: function argument word 2493 R9: GOT pointer 2494 R10: stack limit (used only if stack checking if enabled) 2495 R11: argument (frame) pointer 2496 R12: temporary workspace 2497 R13: stack pointer 2498 R14: link register 2499 R15: program counter 2500 2501 ==> U-Boot will use R8 to hold a pointer to the global data 2502 2503 2504 2505Memory Management: 2506------------------ 2507 2508U-Boot runs in system state and uses physical addresses, i.e. the 2509MMU is not used either for address mapping nor for memory protection. 2510 2511The available memory is mapped to fixed addresses using the memory 2512controller. In this process, a contiguous block is formed for each 2513memory type (Flash, SDRAM, SRAM), even when it consists of several 2514physical memory banks. 2515 2516U-Boot is installed in the first 128 kB of the first Flash bank (on 2517TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2518booting and sizing and initializing DRAM, the code relocates itself 2519to the upper end of DRAM. Immediately below the U-Boot code some 2520memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2521configuration setting]. Below that, a structure with global Board 2522Info data is placed, followed by the stack (growing downward). 2523 2524Additionally, some exception handler code is copied to the low 8 kB 2525of DRAM (0x00000000 ... 0x00001FFF). 2526 2527So a typical memory configuration with 16 MB of DRAM could look like 2528this: 2529 2530 0x0000 0000 Exception Vector code 2531 : 2532 0x0000 1FFF 2533 0x0000 2000 Free for Application Use 2534 : 2535 : 2536 2537 : 2538 : 2539 0x00FB FF20 Monitor Stack (Growing downward) 2540 0x00FB FFAC Board Info Data and permanent copy of global data 2541 0x00FC 0000 Malloc Arena 2542 : 2543 0x00FD FFFF 2544 0x00FE 0000 RAM Copy of Monitor Code 2545 ... eventually: LCD or video framebuffer 2546 ... eventually: pRAM (Protected RAM - unchanged by reset) 2547 0x00FF FFFF [End of RAM] 2548 2549 2550System Initialization: 2551---------------------- 2552 2553In the reset configuration, U-Boot starts at the reset entry point 2554(on most PowerPC systens at address 0x00000100). Because of the reset 2555configuration for CS0# this is a mirror of the onboard Flash memory. 2556To be able to re-map memory U-Boot then jumps to it's link address. 2557To be able to implement the initialization code in C, a (small!) 2558initial stack is set up in the internal Dual Ported RAM (in case CPUs 2559which provide such a feature like MPC8xx or MPC8260), or in a locked 2560part of the data cache. After that, U-Boot initializes the CPU core, 2561the caches and the SIU. 2562 2563Next, all (potentially) available memory banks are mapped using a 2564preliminary mapping. For example, we put them on 512 MB boundaries 2565(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2566on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2567programmed for SDRAM access. Using the temporary configuration, a 2568simple memory test is run that determines the size of the SDRAM 2569banks. 2570 2571When there is more than one SDRAM bank, and the banks are of 2572different size, the larger is mapped first. For equal size, the first 2573bank (CS2#) is mapped first. The first mapping is always for address 25740x00000000, with any additional banks following immediately to create 2575contiguous memory starting from 0. 2576 2577Then, the monitor installs itself at the upper end of the SDRAM area 2578and allocates memory for use by malloc() and for the global Board 2579Info data; also, the exception vector code is copied to the low RAM 2580pages, and the final stack is set up. 2581 2582Only after this relocation will you have a "normal" C environment; 2583until that you are restricted in several ways, mostly because you are 2584running from ROM, and because the code will have to be relocated to a 2585new address in RAM. 2586 2587 2588U-Boot Porting Guide: 2589---------------------- 2590 2591[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2592list, Octover 2002] 2593 2594 2595int main (int argc, char *argv[]) 2596{ 2597 sighandler_t no_more_time; 2598 2599 signal (SIGALRM, no_more_time); 2600 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2601 2602 if (available_money > available_manpower) { 2603 pay consultant to port U-Boot; 2604 return 0; 2605 } 2606 2607 Download latest U-Boot source; 2608 2609 if (clueless) { 2610 email ("Hi, I am new to U-Boot, how do I get started?"); 2611 } 2612 2613 while (learning) { 2614 Read the README file in the top level directory; 2615 Read http://www.denx.de/re/DPLG.html 2616 Read the source, Luke; 2617 } 2618 2619 if (available_money > toLocalCurrency ($2500)) { 2620 Buy a BDI2000; 2621 } else { 2622 Add a lot of aggravation and time; 2623 } 2624 2625 Create your own board support subdirectory; 2626 2627 while (!running) { 2628 do { 2629 Add / modify source code; 2630 } until (compiles); 2631 Debug; 2632 if (clueless) 2633 email ("Hi, I am having problems..."); 2634 } 2635 Send patch file to Wolfgang; 2636 2637 return 0; 2638} 2639 2640void no_more_time (int sig) 2641{ 2642 hire_a_guru(); 2643} 2644 2645 2646 2647Coding Standards: 2648----------------- 2649 2650All contributions to U-Boot should conform to the Linux kernel 2651coding style; see the file "Documentation/CodingStyle" in your Linux 2652kernel source directory. 2653 2654Please note that U-Boot is implemented in C (and to some small parts 2655in Assembler); no C++ is used, so please do not use C++ style 2656comments (//) in your code. 2657 2658Submissions which do not conform to the standards may be returned 2659with a request to reformat the changes. 2660 2661 2662Submitting Patches: 2663------------------- 2664 2665Since the number of patches for U-Boot is growing, we need to 2666establish some rules. Submissions which do not conform to these rules 2667may be rejected, even when they contain important and valuable stuff. 2668 2669 2670When you send a patch, please include the following information with 2671it: 2672 2673* For bug fixes: a description of the bug and how your patch fixes 2674 this bug. Please try to include a way of demonstrating that the 2675 patch actually fixes something. 2676 2677* For new features: a description of the feature and your 2678 implementation. 2679 2680* A CHANGELOG entry as plaintext (separate from the patch) 2681 2682* For major contributions, your entry to the CREDITS file 2683 2684* When you add support for a new board, don't forget to add this 2685 board to the MAKEALL script, too. 2686 2687* If your patch adds new configuration options, don't forget to 2688 document these in the README file. 2689 2690* The patch itself. If you are accessing the CVS repository use "cvs 2691 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2692 version of diff does not support these options, then get the latest 2693 version of GNU diff. 2694 2695 We accept patches as plain text, MIME attachments or as uuencoded 2696 gzipped text. 2697 2698Notes: 2699 2700* Before sending the patch, run the MAKEALL script on your patched 2701 source tree and make sure that no errors or warnings are reported 2702 for any of the boards. 2703 2704* Keep your modifications to the necessary minimum: A patch 2705 containing several unrelated changes or arbitrary reformats will be 2706 returned with a request to re-formatting / split it. 2707 2708* If you modify existing code, make sure that your new code does not 2709 add to the memory footprint of the code ;-) Small is beautiful! 2710 When adding new features, these should compile conditionally only 2711 (using #ifdef), and the resulting code with the new feature 2712 disabled must not need more memory than the old code without your 2713 modification. 2714