1# 2# (C) Copyright 2000 - 2002 3# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4# 5# See file CREDITS for list of people who contributed to this 6# project. 7# 8# This program is free software; you can redistribute it and/or 9# modify it under the terms of the GNU General Public License as 10# published by the Free Software Foundation; either version 2 of 11# the License, or (at your option) any later version. 12# 13# This program is distributed in the hope that it will be useful, 14# but WITHOUT ANY WARRANTY; without even the implied warranty of 15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16# GNU General Public License for more details. 17# 18# You should have received a copy of the GNU General Public License 19# along with this program; if not, write to the Free Software 20# Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21# MA 02111-1307 USA 22# 23 24Summary: 25======== 26 27This directory contains the source code for U-Boot, a boot loader for 28Embedded boards based on PowerPC and ARM processors, which can be 29installed in a boot ROM and used to initialize and test the hardware 30or to download and run application code. 31 32The development of U-Boot is closely related to Linux: some parts of 33the source code originate in the Linux source tree, we have some 34header files in common, and special provision has been made to 35support booting of Linux images. 36 37Some attention has been paid to make this software easily 38configurable and extendable. For instance, all monitor commands are 39implemented with the same call interface, so that it's very easy to 40add new commands. Also, instead of permanently adding rarely used 41code (for instance hardware test utilities) to the monitor, you can 42load and run it dynamically. 43 44 45Status: 46======= 47 48In general, all boards for which a configuration option exists in the 49Makefile have been tested to some extent and can be considered 50"working". In fact, many of them are used in production systems. 51 52In case of problems see the CHANGELOG and CREDITS files to find out 53who contributed the specific port. 54 55 56Where to get help: 57================== 58 59In case you have questions about, problems with or contributions for 60U-Boot you should send a message to the U-Boot mailing list at 61<u-boot-users@lists.sourceforge.net>. There is also an archive of 62previous traffic on the mailing list - please search the archive 63before asking FAQ's. Please see 64http://lists.sourceforge.net/lists/listinfo/u-boot-users/ 65 66 67Where we come from: 68=================== 69 70- start from 8xxrom sources 71- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 72- clean up code 73- make it easier to add custom boards 74- make it possible to add other [PowerPC] CPUs 75- extend functions, especially: 76 * Provide extended interface to Linux boot loader 77 * S-Record download 78 * network boot 79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot 80- create ARMBoot project (http://sourceforge.net/projects/armboot) 81- add other CPU families (starting with ARM) 82- create U-Boot project (http://sourceforge.net/projects/u-boot) 83 84 85Names and Spelling: 86=================== 87 88The "official" name of this project is "Das U-Boot". The spelling 89"U-Boot" shall be used in all written text (documentation, comments 90in source files etc.). Example: 91 92 This is the README file for the U-Boot project. 93 94File names etc. shall be based on the string "u-boot". Examples: 95 96 include/asm-ppc/u-boot.h 97 98 #include <asm/u-boot.h> 99 100Variable names, preprocessor constants etc. shall be either based on 101the string "u_boot" or on "U_BOOT". Example: 102 103 U_BOOT_VERSION u_boot_logo 104 IH_OS_U_BOOT u_boot_hush_start 105 106 107Directory Hierarchy: 108==================== 109 110- board Board dependend files 111- common Misc architecture independend functions 112- cpu CPU specific files 113- disk Code for disk drive partition handling 114- doc Documentation (don't expect too much) 115- drivers Common used device drivers 116- dtt Digital Thermometer and Thermostat drivers 117- examples Example code for standalone applications, etc. 118- include Header Files 119- disk Harddisk interface code 120- net Networking code 121- ppc Files generic to PowerPC architecture 122- post Power On Self Test 123- post/arch Symlink to architecture specific Power On Self Test 124- post/arch-ppc PowerPC architecture specific Power On Self Test 125- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test 126- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test 127- rtc Real Time Clock drivers 128- tools Tools to build S-Record or U-Boot images, etc. 129 130- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 131- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs 132- cpu/mpc824x Files specific to Motorola MPC824x CPUs 133- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 134- cpu/ppc4xx Files specific to IBM 4xx CPUs 135 136- board/RPXClassic 137 Files specific to RPXClassic boards 138- board/RPXlite Files specific to RPXlite boards 139- board/c2mon Files specific to c2mon boards 140- board/cogent Files specific to Cogent boards 141 (need further configuration) 142 Files specific to CPCIISER4 boards 143- board/cpu86 Files specific to CPU86 boards 144- board/cray/ Files specific to boards manufactured by Cray 145- board/cray/L1 Files specific to L1 boards 146- board/cu824 Files specific to CU824 boards 147- board/ebony Files specific to IBM Ebony board 148- board/eric Files specific to ERIC boards 149- board/esd/ Files specific to boards manufactured by ESD 150- board/esd/adciop Files specific to ADCIOP boards 151- board/esd/ar405 Files specific to AR405 boards 152- board/esd/canbt Files specific to CANBT boards 153- board/esd/cpci405 Files specific to CPCI405 boards 154- board/esd/cpciiser4 Files specific to CPCIISER4 boards 155- board/esd/common Common files for ESD boards 156- board/esd/dasa_sim Files specific to DASA_SIM boards 157- board/esd/du405 Files specific to DU405 boards 158- board/esd/ocrtc Files specific to OCRTC boards 159- board/esd/pci405 Files specific to PCI405 boards 160- board/esteem192e 161 Files specific to ESTEEM192E boards 162- board/etx094 Files specific to ETX_094 boards 163- board/evb64260 164 Files specific to EVB64260 boards 165- board/fads Files specific to FADS boards 166- board/flagadm Files specific to FLAGADM boards 167- board/gen860t Files specific to GEN860T boards 168- board/genietv Files specific to GENIETV boards 169- board/gth Files specific to GTH boards 170- board/hermes Files specific to HERMES boards 171- board/hymod Files specific to HYMOD boards 172- board/icu862 Files specific to ICU862 boards 173- board/ip860 Files specific to IP860 boards 174- board/iphase4539 175 Files specific to Interphase4539 boards 176- board/ivm Files specific to IVMS8/IVML24 boards 177- board/lantec Files specific to LANTEC boards 178- board/lwmon Files specific to LWMON boards 179- board/mbx8xx Files specific to MBX boards 180- board/mpc8260ads 181 Files specific to MMPC8260ADS boards 182- board/mpl/ Files specific to boards manufactured by MPL 183- board/mpl/common Common files for MPL boards 184- board/mpl/pip405 Files specific to PIP405 boards 185- board/mpl/mip405 Files specific to MIP405 boards 186- board/musenki Files specific to MUSEKNI boards 187- board/mvs1 Files specific to MVS1 boards 188- board/nx823 Files specific to NX823 boards 189- board/oxc Files specific to OXC boards 190- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 191- board/pm826 Files specific to PM826 boards 192- board/ppmc8260 193 Files specific to PPMC8260 boards 194- board/rpxsuper 195 Files specific to RPXsuper boards 196- board/rsdproto 197 Files specific to RSDproto boards 198- board/sandpoint 199 Files specific to Sandpoint boards 200- board/sbc8260 Files specific to SBC8260 boards 201- board/sacsng Files specific to SACSng boards 202- board/siemens Files specific to boards manufactured by Siemens AG 203- board/siemens/CCM Files specific to CCM boards 204- board/siemens/IAD210 Files specific to IAD210 boards 205- board/siemens/SCM Files specific to SCM boards 206- board/siemens/pcu_e Files specific to PCU_E boards 207- board/sixnet Files specific to SIXNET boards 208- board/spd8xx Files specific to SPD8xxTS boards 209- board/tqm8260 Files specific to TQM8260 boards 210- board/tqm8xx Files specific to TQM8xxL boards 211- board/w7o Files specific to W7O boards 212- board/walnut405 213 Files specific to Walnut405 boards 214- board/westel/ Files specific to boards manufactured by Westel Wireless 215- board/westel/amx860 Files specific to AMX860 boards 216- board/utx8245 Files specific to UTX8245 boards 217 218Software Configuration: 219======================= 220 221Configuration is usually done using C preprocessor defines; the 222rationale behind that is to avoid dead code whenever possible. 223 224There are two classes of configuration variables: 225 226* Configuration _OPTIONS_: 227 These are selectable by the user and have names beginning with 228 "CONFIG_". 229 230* Configuration _SETTINGS_: 231 These depend on the hardware etc. and should not be meddled with if 232 you don't know what you're doing; they have names beginning with 233 "CFG_". 234 235Later we will add a configuration tool - probably similar to or even 236identical to what's used for the Linux kernel. Right now, we have to 237do the configuration by hand, which means creating some symbolic 238links and editing some configuration files. We use the TQM8xxL boards 239as an example here. 240 241 242Selection of Processor Architecture and Board Type: 243--------------------------------------------------- 244 245For all supported boards there are ready-to-use default 246configurations available; just type "make <board_name>_config". 247 248Example: For a TQM823L module type: 249 250 cd u-boot 251 make TQM823L_config 252 253For the Cogent platform, you need to specify the cpu type as well; 254e.g. "make cogent_mpc8xx_config". And also configure the cogent 255directory according to the instructions in cogent/README. 256 257 258Configuration Options: 259---------------------- 260 261Configuration depends on the combination of board and CPU type; all 262such information is kept in a configuration file 263"include/configs/<board_name>.h". 264 265Example: For a TQM823L module, all configuration settings are in 266"include/configs/TQM823L.h". 267 268 269Many of the options are named exactly as the corresponding Linux 270kernel configuration options. The intention is to make it easier to 271build a config tool - later. 272 273 274The following options need to be configured: 275 276- CPU Type: Define exactly one of 277 278 PowerPC based CPUs: 279 ------------------- 280 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 281 or CONFIG_MPC824X, CONFIG_MPC8260 282 or CONFIG_IOP480 283 or CONFIG_405GP 284 or CONFIG_440 285 or CONFIG_MPC74xx 286 287 ARM based CPUs: 288 --------------- 289 CONFIG_SA1110 290 CONFIG_ARM7 291 CONFIG_PXA250 292 293 294- Board Type: Define exactly one of 295 296 PowerPC based boards: 297 --------------------- 298 299 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 300 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 301 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 302 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 303 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 304 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 305 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 306 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 307 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 308 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 309 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 310 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 311 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 312 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 313 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 314 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 315 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 316 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 317 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 318 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 319 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 320 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 321 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 322 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 323 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 324 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 325 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 326 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 327 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 328 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L 329 330 ARM based boards: 331 ----------------- 332 333 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 334 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 335 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 336 CONFIG_TRAB 337 338 339- CPU Module Type: (if CONFIG_COGENT is defined) 340 Define exactly one of 341 CONFIG_CMA286_60_OLD 342--- FIXME --- not tested yet: 343 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 344 CONFIG_CMA287_23, CONFIG_CMA287_50 345 346- Motherboard Type: (if CONFIG_COGENT is defined) 347 Define exactly one of 348 CONFIG_CMA101, CONFIG_CMA102 349 350- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 351 Define one or more of 352 CONFIG_CMA302 353 354- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 355 Define one or more of 356 CONFIG_LCD_HEARTBEAT - update a character position on 357 the lcd display every second with 358 a "rotator" |\-/|\-/ 359 360- MPC824X Family Member (if CONFIG_MPC824X is defined) 361 Define exactly one of 362 CONFIG_MPC8240, CONFIG_MPC8245 363 364- 8xx CPU Options: (if using an 8xx cpu) 365 Define one or more of 366 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 367 no 32KHz reference PIT/RTC clock 368 369- Clock Interface: 370 CONFIG_CLOCKS_IN_MHZ 371 372 U-Boot stores all clock information in Hz 373 internally. For binary compatibility with older Linux 374 kernels (which expect the clocks passed in the 375 bd_info data to be in MHz) the environment variable 376 "clocks_in_mhz" can be defined so that U-Boot 377 converts clock data to MHZ before passing it to the 378 Linux kernel. 379 380 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 381 "clocks_in_mhz=1" is automatically included in the 382 default environment. 383 384- Console Interface: 385 Depending on board, define exactly one serial port 386 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 387 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 388 console by defining CONFIG_8xx_CONS_NONE 389 390 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 391 port routines must be defined elsewhere 392 (i.e. serial_init(), serial_getc(), ...) 393 394 CONFIG_CFB_CONSOLE 395 Enables console device for a color framebuffer. Needs following 396 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 397 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 398 (default big endian) 399 VIDEO_HW_RECTFILL graphic chip supports 400 rectangle fill 401 (cf. smiLynxEM) 402 VIDEO_HW_BITBLT graphic chip supports 403 bit-blit (cf. smiLynxEM) 404 VIDEO_VISIBLE_COLS visible pixel columns 405 (cols=pitch) 406 VIDEO_VISIBLE_ROWS visible pixel rows 407 VIDEO_PIXEL_SIZE bytes per pixel 408 VIDEO_DATA_FORMAT graphic data format 409 (0-5, cf. cfb_console.c) 410 VIDEO_FB_ADRS framebuffer address 411 VIDEO_KBD_INIT_FCT keyboard int fct 412 (i.e. i8042_kbd_init()) 413 VIDEO_TSTC_FCT test char fct 414 (i.e. i8042_tstc) 415 VIDEO_GETC_FCT get char fct 416 (i.e. i8042_getc) 417 CONFIG_CONSOLE_CURSOR cursor drawing on/off 418 (requires blink timer 419 cf. i8042.c) 420 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 421 CONFIG_CONSOLE_TIME display time/date info in 422 upper right corner 423 (requires CFG_CMD_DATE) 424 CONFIG_VIDEO_LOGO display Linux logo in 425 upper left corner 426 CONFIG_CONSOLE_EXTRA_INFO 427 addional board info beside 428 the logo 429 430 When CONFIG_CFB_CONSOLE is defined, video console is 431 default i/o. Serial console can be forced with 432 environment 'console=serial'. 433 434- Console Baudrate: 435 CONFIG_BAUDRATE - in bps 436 Select one of the baudrates listed in 437 CFG_BAUDRATE_TABLE, see below. 438 439- Interrupt driven serial port input: 440 CONFIG_SERIAL_SOFTWARE_FIFO 441 442 PPC405GP only. 443 Use an interrupt handler for receiving data on the 444 serial port. It also enables using hardware handshake 445 (RTS/CTS) and UART's built-in FIFO. Set the number of 446 bytes the interrupt driven input buffer should have. 447 448 Set to 0 to disable this feature (this is the default). 449 This will also disable hardware handshake. 450 451- Boot Delay: CONFIG_BOOTDELAY - in seconds 452 Delay before automatically booting the default image; 453 set to -1 to disable autoboot. 454 455 See doc/README.autoboot for these options that 456 work with CONFIG_BOOTDELAY. None are required. 457 CONFIG_BOOT_RETRY_TIME 458 CONFIG_BOOT_RETRY_MIN 459 CONFIG_AUTOBOOT_KEYED 460 CONFIG_AUTOBOOT_PROMPT 461 CONFIG_AUTOBOOT_DELAY_STR 462 CONFIG_AUTOBOOT_STOP_STR 463 CONFIG_AUTOBOOT_DELAY_STR2 464 CONFIG_AUTOBOOT_STOP_STR2 465 CONFIG_ZERO_BOOTDELAY_CHECK 466 CONFIG_RESET_TO_RETRY 467 468- Autoboot Command: 469 CONFIG_BOOTCOMMAND 470 Only needed when CONFIG_BOOTDELAY is enabled; 471 define a command string that is automatically executed 472 when no character is read on the console interface 473 within "Boot Delay" after reset. 474 475 CONFIG_BOOTARGS 476 This can be used to pass arguments to the bootm 477 command. The value of CONFIG_BOOTARGS goes into the 478 environment value "bootargs". 479 480 CONFIG_RAMBOOT and CONFIG_NFSBOOT 481 The value of these goes into the environment as 482 "ramboot" and "nfsboot" respectively, and can be used 483 as a convenience, when switching between booting from 484 ram and nfs. 485 486- Pre-Boot Commands: 487 CONFIG_PREBOOT 488 489 When this option is #defined, the existence of the 490 environment variable "preboot" will be checked 491 immediately before starting the CONFIG_BOOTDELAY 492 countdown and/or running the auto-boot command resp. 493 entering interactive mode. 494 495 This feature is especially useful when "preboot" is 496 automatically generated or modified. For an example 497 see the LWMON board specific code: here "preboot" is 498 modified when the user holds down a certain 499 combination of keys on the (special) keyboard when 500 booting the systems 501 502- Serial Download Echo Mode: 503 CONFIG_LOADS_ECHO 504 If defined to 1, all characters received during a 505 serial download (using the "loads" command) are 506 echoed back. This might be needed by some terminal 507 emulations (like "cu"), but may as well just take 508 time on others. This setting #define's the initial 509 value of the "loads_echo" environment variable. 510 511- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 512 CONFIG_KGDB_BAUDRATE 513 Select one of the baudrates listed in 514 CFG_BAUDRATE_TABLE, see below. 515 516- Monitor Functions: 517 CONFIG_COMMANDS 518 Most monitor functions can be selected (or 519 de-selected) by adjusting the definition of 520 CONFIG_COMMANDS; to select individual functions, 521 #define CONFIG_COMMANDS by "OR"ing any of the 522 following values: 523 524 #define enables commands: 525 ------------------------- 526 CFG_CMD_ASKENV * ask for env variable 527 CFG_CMD_BDI bdinfo 528 CFG_CMD_BEDBUG Include BedBug Debugger 529 CFG_CMD_BOOTD bootd 530 CFG_CMD_CACHE icache, dcache 531 CFG_CMD_CONSOLE coninfo 532 CFG_CMD_DATE * support for RTC, date/time... 533 CFG_CMD_DHCP DHCP support 534 CFG_CMD_ECHO * echo arguments 535 CFG_CMD_EEPROM * EEPROM read/write support 536 CFG_CMD_ELF bootelf, bootvx 537 CFG_CMD_ENV saveenv 538 CFG_CMD_FDC * Floppy Disk Support 539 CFG_CMD_FDOS * Dos diskette Support 540 CFG_CMD_FLASH flinfo, erase, protect 541 CFG_CMD_FPGA FPGA device initialization support 542 CFG_CMD_I2C * I2C serial bus support 543 CFG_CMD_IDE * IDE harddisk support 544 CFG_CMD_IMI iminfo 545 CFG_CMD_IMMAP * IMMR dump support 546 CFG_CMD_IRQ * irqinfo 547 CFG_CMD_KGDB * kgdb 548 CFG_CMD_LOADB loadb 549 CFG_CMD_LOADS loads 550 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 551 loop, mtest 552 CFG_CMD_MII MII utility commands 553 CFG_CMD_NET bootp, tftpboot, rarpboot 554 CFG_CMD_PCI * pciinfo 555 CFG_CMD_PCMCIA * PCMCIA support 556 CFG_CMD_REGINFO * Register dump 557 CFG_CMD_RUN run command in env variable 558 CFG_CMD_SCSI * SCSI Support 559 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 560 CFG_CMD_SPI * SPI serial bus support 561 CFG_CMD_USB * USB support 562 CFG_CMD_BSP * Board SPecific functions 563 ----------------------------------------------- 564 CFG_CMD_ALL all 565 566 CFG_CMD_DFL Default configuration; at the moment 567 this is includes all commands, except 568 the ones marked with "*" in the list 569 above. 570 571 If you don't define CONFIG_COMMANDS it defaults to 572 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 573 override the default settings in the respective 574 include file. 575 576 EXAMPLE: If you want all functions except of network 577 support you can write: 578 579 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 580 581 582 Note: Don't enable the "icache" and "dcache" commands 583 (configuration option CFG_CMD_CACHE) unless you know 584 what you (and your U-Boot users) are doing. Data 585 cache cannot be enabled on systems like the 8xx or 586 8260 (where accesses to the IMMR region must be 587 uncached), and it cannot be disabled on all other 588 systems where we (mis-) use the data cache to hold an 589 initial stack and some data. 590 591 592 XXX - this list needs to get updated! 593 594- Watchdog: 595 CONFIG_WATCHDOG 596 If this variable is defined, it enables watchdog 597 support. There must support in the platform specific 598 code for a watchdog. For the 8xx and 8260 CPUs, the 599 SIU Watchdog feature is enabled in the SYPCR 600 register. 601 602- Real-Time Clock: 603 604 When CFG_CMD_DATE is selected, the type of the RTC 605 has to be selected, too. Define exactly one of the 606 following options: 607 608 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 609 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 610 CONFIG_RTC_MC146818 - use MC146818 RTC 611 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 612 613- Timestamp Support: 614 615 When CONFIG_TIMESTAMP is selected, the timestamp 616 (date and time) of an image is printed by image 617 commands like bootm or iminfo. This option is 618 automatically enabled when you select CFG_CMD_DATE . 619 620- Partition Support: 621 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 622 and/or CONFIG_ISO_PARTITION 623 624 If IDE or SCSI support is enabled (CFG_CMD_IDE or 625 CFG_CMD_SCSI) you must configure support for at least 626 one partition type as well. 627 628- IDE Reset method: 629 CONFIG_IDE_RESET_ROUTINE 630 631 Set this to define that instead of a reset Pin, the 632 routine ide_set_reset(int idereset) will be used. 633 634- ATAPI Support: 635 CONFIG_ATAPI 636 637 Set this to enable ATAPI support. 638 639- SCSI Support: 640 At the moment only there is only support for the 641 SYM53C8XX SCSI controller; define 642 CONFIG_SCSI_SYM53C8XX to enable it. 643 644 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 645 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 646 CFG_SCSI_MAX_LUN] can be adjusted to define the 647 maximum numbers of LUNs, SCSI ID's and target 648 devices. 649 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 650 651- NETWORK Support (PCI): 652 CONFIG_EEPRO100 653 Support for Intel 82557/82559/82559ER chips. 654 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 655 write routine for first time initialisation. 656 657 CONFIG_TULIP 658 Support for Digital 2114x chips. 659 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 660 modem chip initialisation (KS8761/QS6611). 661 662 CONFIG_NATSEMI 663 Support for National dp83815 chips. 664 665 CONFIG_NS8382X 666 Support for National dp8382[01] gigabit chips. 667 668- USB Support: 669 At the moment only the UHCI host controller is 670 supported (PIP405, MIP405); define 671 CONFIG_USB_UHCI to enable it. 672 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 673 end define CONFIG_USB_STORAGE to enable the USB 674 storage devices. 675 Note: 676 Supported are USB Keyboards and USB Floppy drives 677 (TEAC FD-05PUB). 678 679- Keyboard Support: 680 CONFIG_ISA_KEYBOARD 681 682 Define this to enable standard (PC-Style) keyboard 683 support 684 685 CONFIG_I8042_KBD 686 Standard PC keyboard driver with US (is default) and 687 GERMAN key layout (switch via environment 'keymap=de') support. 688 Export function i8042_kbd_init, i8042_tstc and i8042_getc 689 for cfb_console. Supports cursor blinking. 690 691- Video support: 692 CONFIG_VIDEO 693 694 Define this to enable video support (for output to 695 video). 696 697 CONFIG_VIDEO_CT69000 698 699 Enable Chips & Technologies 69000 Video chip 700 701 CONFIG_VIDEO_SMI_LYNXEM 702 Enable Silicon Motion SMI 712/710/810 Video chip 703 Videomode are selected via environment 'videomode' with 704 standard LiLo mode numbers. 705 Following modes are supported (* is default): 706 707 800x600 1024x768 1280x1024 708 256 (8bit) 303* 305 307 709 65536 (16bit) 314 317 31a 710 16,7 Mill (24bit) 315 318 31b 711 (i.e. setenv videomode 317; saveenv; reset;) 712 713- LCD Support: CONFIG_LCD 714 715 Define this to enable LCD support (for output to LCD 716 display); also select one of the supported displays 717 by defining one of these: 718 719 CONFIG_NEC_NL6648AC33: 720 721 NEC NL6648AC33-18. Active, color, single scan. 722 723 CONFIG_NEC_NL6648BC20 724 725 NEC NL6648BC20-08. 6.5", 640x480. 726 Active, color, single scan. 727 728 CONFIG_SHARP_16x9 729 730 Sharp 320x240. Active, color, single scan. 731 It isn't 16x9, and I am not sure what it is. 732 733 CONFIG_SHARP_LQ64D341 734 735 Sharp LQ64D341 display, 640x480. 736 Active, color, single scan. 737 738 CONFIG_HLD1045 739 740 HLD1045 display, 640x480. 741 Active, color, single scan. 742 743 CONFIG_OPTREX_BW 744 745 Optrex CBL50840-2 NF-FW 99 22 M5 746 or 747 Hitachi LMG6912RPFC-00T 748 or 749 Hitachi SP14Q002 750 751 320x240. Black & white. 752 753 Normally display is black on white background; define 754 CFG_WHITE_ON_BLACK to get it inverted. 755 756- Ethernet address: 757 CONFIG_ETHADDR 758 CONFIG_ETH2ADDR 759 CONFIG_ETH3ADDR 760 761 Define a default value for ethernet address to use 762 for the respective ethernet interface, in case this 763 is not determined automatically. 764 765- IP address: 766 CONFIG_IPADDR 767 768 Define a default value for the IP address to use for 769 the default ethernet interface, in case this is not 770 determined through e.g. bootp. 771 772- Server IP address: 773 CONFIG_SERVERIP 774 775 Defines a default value for theIP address of a TFTP 776 server to contact when using the "tftboot" command. 777 778- BOOTP Recovery Mode: 779 CONFIG_BOOTP_RANDOM_DELAY 780 781 If you have many targets in a network that try to 782 boot using BOOTP, you may want to avoid that all 783 systems send out BOOTP requests at precisely the same 784 moment (which would happen for instance at recovery 785 from a power failure, when all systems will try to 786 boot, thus flooding the BOOTP server. Defining 787 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 788 inserted before sending out BOOTP requests. The 789 following delays are insterted then: 790 791 1st BOOTP request: delay 0 ... 1 sec 792 2nd BOOTP request: delay 0 ... 2 sec 793 3rd BOOTP request: delay 0 ... 4 sec 794 4th and following 795 BOOTP requests: delay 0 ... 8 sec 796 797- Status LED: CONFIG_STATUS_LED 798 799 Several configurations allow to display the current 800 status using a LED. For instance, the LED will blink 801 fast while running U-Boot code, stop blinking as 802 soon as a reply to a BOOTP request was received, and 803 start blinking slow once the Linux kernel is running 804 (supported by a status LED driver in the Linux 805 kernel). Defining CONFIG_STATUS_LED enables this 806 feature in U-Boot. 807 808- CAN Support: CONFIG_CAN_DRIVER 809 810 Defining CONFIG_CAN_DRIVER enables CAN driver support 811 on those systems that support this (optional) 812 feature, like the TQM8xxL modules. 813 814- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 815 816 Enables I2C serial bus commands. If this is selected, 817 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 818 to include the appropriate I2C driver. 819 820 See also: common/cmd_i2c.c for a description of the 821 command line interface. 822 823 824 CONFIG_HARD_I2C 825 826 Selects the CPM hardware driver for I2C. 827 828 CONFIG_SOFT_I2C 829 830 Use software (aka bit-banging) driver instead of CPM 831 or similar hardware support for I2C. This is configured 832 via the following defines. 833 834 I2C_INIT 835 836 (Optional). Any commands necessary to enable I2C 837 controller or configure ports. 838 839 I2C_PORT 840 841 (Only for MPC8260 CPU). The I/O port to use (the code 842 assumes both bits are on the same port). Valid values 843 are 0..3 for ports A..D. 844 845 I2C_ACTIVE 846 847 The code necessary to make the I2C data line active 848 (driven). If the data line is open collector, this 849 define can be null. 850 851 I2C_TRISTATE 852 853 The code necessary to make the I2C data line tri-stated 854 (inactive). If the data line is open collector, this 855 define can be null. 856 857 I2C_READ 858 859 Code that returns TRUE if the I2C data line is high, 860 FALSE if it is low. 861 862 I2C_SDA(bit) 863 864 If <bit> is TRUE, sets the I2C data line high. If it 865 is FALSE, it clears it (low). 866 867 I2C_SCL(bit) 868 869 If <bit> is TRUE, sets the I2C clock line high. If it 870 is FALSE, it clears it (low). 871 872 I2C_DELAY 873 874 This delay is invoked four times per clock cycle so this 875 controls the rate of data transfer. The data rate thus 876 is 1 / (I2C_DELAY * 4). 877 878- SPI Support: CONFIG_SPI 879 880 Enables SPI driver (so far only tested with 881 SPI EEPROM, also an instance works with Crystal A/D and 882 D/As on the SACSng board) 883 884 CONFIG_SPI_X 885 886 Enables extended (16-bit) SPI EEPROM addressing. 887 (symmetrical to CONFIG_I2C_X) 888 889 CONFIG_SOFT_SPI 890 891 Enables a software (bit-bang) SPI driver rather than 892 using hardware support. This is a general purpose 893 driver that only requires three general I/O port pins 894 (two outputs, one input) to function. If this is 895 defined, the board configuration must define several 896 SPI configuration items (port pins to use, etc). For 897 an example, see include/configs/sacsng.h. 898 899- FPGA Support: CONFIG_FPGA_COUNT 900 901 Specify the number of FPGA devices to support. 902 903 CONFIG_FPGA 904 905 Used to specify the types of FPGA devices. For 906 example, 907 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 908 909 CFG_FPGA_PROG_FEEDBACK 910 911 Enable printing of hash marks during FPGA 912 configuration. 913 914 CFG_FPGA_CHECK_BUSY 915 916 Enable checks on FPGA configuration interface busy 917 status by the configuration function. This option 918 will require a board or device specific function to 919 be written. 920 921 CONFIG_FPGA_DELAY 922 923 If defined, a function that provides delays in the 924 FPGA configuration driver. 925 926 CFG_FPGA_CHECK_CTRLC 927 928 Allow Control-C to interrupt FPGA configuration 929 930 CFG_FPGA_CHECK_ERROR 931 932 Check for configuration errors during FPGA bitfile 933 loading. For example, abort during Virtex II 934 configuration if the INIT_B line goes low (which 935 indicated a CRC error). 936 937 CFG_FPGA_WAIT_INIT 938 939 Maximum time to wait for the INIT_B line to deassert 940 after PROB_B has been deasserted during a Virtex II 941 FPGA configuration sequence. The default time is 500 mS. 942 943 CFG_FPGA_WAIT_BUSY 944 945 Maximum time to wait for BUSY to deassert during 946 Virtex II FPGA configuration. The default is 5 mS. 947 948 CFG_FPGA_WAIT_CONFIG 949 950 Time to wait after FPGA configuration. The default is 951 200 mS. 952 953- FPGA Support: CONFIG_FPGA_COUNT 954 955 Specify the number of FPGA devices to support. 956 957 CONFIG_FPGA 958 959 Used to specify the types of FPGA devices. For example, 960 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 961 962 CFG_FPGA_PROG_FEEDBACK 963 964 Enable printing of hash marks during FPGA configuration. 965 966 CFG_FPGA_CHECK_BUSY 967 968 Enable checks on FPGA configuration interface busy 969 status by the configuration function. This option 970 will require a board or device specific function to 971 be written. 972 973 CONFIG_FPGA_DELAY 974 975 If defined, a function that provides delays in the FPGA 976 configuration driver. 977 978 CFG_FPGA_CHECK_CTRLC 979 Allow Control-C to interrupt FPGA configuration 980 981 CFG_FPGA_CHECK_ERROR 982 983 Check for configuration errors during FPGA bitfile 984 loading. For example, abort during Virtex II 985 configuration if the INIT_B line goes low (which 986 indicated a CRC error). 987 988 CFG_FPGA_WAIT_INIT 989 990 Maximum time to wait for the INIT_B line to deassert 991 after PROB_B has been deasserted during a Virtex II 992 FPGA configuration sequence. The default time is 500 993 mS. 994 995 CFG_FPGA_WAIT_BUSY 996 997 Maximum time to wait for BUSY to deassert during 998 Virtex II FPGA configuration. The default is 5 mS. 999 1000 CFG_FPGA_WAIT_CONFIG 1001 1002 Time to wait after FPGA configuration. The default is 1003 200 mS. 1004 1005- Configuration Management: 1006 CONFIG_IDENT_STRING 1007 1008 If defined, this string will be added to the U-Boot 1009 version information (U_BOOT_VERSION) 1010 1011- Vendor Parameter Protection: 1012 1013 U-Boot considers the values of the environment 1014 variables "serial#" (Board Serial Number) and 1015 "ethaddr" (Ethernet Address) to bb parameters that 1016 are set once by the board vendor / manufacturer, and 1017 protects these variables from casual modification by 1018 the user. Once set, these variables are read-only, 1019 and write or delete attempts are rejected. You can 1020 change this behviour: 1021 1022 If CONFIG_ENV_OVERWRITE is #defined in your config 1023 file, the write protection for vendor parameters is 1024 completely disabled. Anybody can change or delte 1025 these parameters. 1026 1027 Alternatively, if you #define _both_ CONFIG_ETHADDR 1028 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1029 ethernet address is installed in the environment, 1030 which can be changed exactly ONCE by the user. [The 1031 serial# is unaffected by this, i. e. it remains 1032 read-only.] 1033 1034- Protected RAM: 1035 CONFIG_PRAM 1036 1037 Define this variable to enable the reservation of 1038 "protected RAM", i. e. RAM which is not overwritten 1039 by U-Boot. Define CONFIG_PRAM to hold the number of 1040 kB you want to reserve for pRAM. You can overwrite 1041 this default value by defining an environment 1042 variable "pram" to the number of kB you want to 1043 reserve. Note that the board info structure will 1044 still show the full amount of RAM. If pRAM is 1045 reserved, a new environment variable "mem" will 1046 automatically be defined to hold the amount of 1047 remaining RAM in a form that can be passed as boot 1048 argument to Linux, for instance like that: 1049 1050 setenv bootargs ... mem=\$(mem) 1051 saveenv 1052 1053 This way you can tell Linux not to use this memory, 1054 either, which results in a memory region that will 1055 not be affected by reboots. 1056 1057 *WARNING* If your board configuration uses automatic 1058 detection of the RAM size, you must make sure that 1059 this memory test is non-destructive. So far, the 1060 following board configurations are known to be 1061 "pRAM-clean": 1062 1063 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1064 HERMES, IP860, RPXlite, LWMON, LANTEC, 1065 PCU_E, FLAGADM, TQM8260 1066 1067- Error Recovery: 1068 CONFIG_PANIC_HANG 1069 1070 Define this variable to stop the system in case of a 1071 fatal error, so that you have to reset it manually. 1072 This is probably NOT a good idea for an embedded 1073 system where you want to system to reboot 1074 automatically as fast as possible, but it may be 1075 useful during development since you can try to debug 1076 the conditions that lead to the situation. 1077 1078 CONFIG_NET_RETRY_COUNT 1079 1080 This variable defines the number of retries for 1081 network operations like ARP, RARP, TFTP, or BOOTP 1082 before giving up the operation. If not defined, a 1083 default value of 5 is used. 1084 1085- Command Interpreter: 1086 CFG_HUSH_PARSER 1087 1088 Define this variable to enable the "hush" shell (from 1089 Busybox) as command line interpreter, thus enabling 1090 powerful command line syntax like 1091 if...then...else...fi conditionals or `&&' and '||' 1092 constructs ("shell scripts"). 1093 1094 If undefined, you get the old, much simpler behaviour 1095 with a somewhat smaller memory footprint. 1096 1097 1098 CFG_PROMPT_HUSH_PS2 1099 1100 This defines the secondary prompt string, which is 1101 printed when the command interpreter needs more input 1102 to complete a command. Usually "> ". 1103 1104 Note: 1105 1106 In the current implementation, the local variables 1107 space and global environment variables space are 1108 separated. Local variables are those you define by 1109 simply typing like `name=value'. To access a local 1110 variable later on, you have write `$name' or 1111 `${name}'; variable directly by typing say `$name' at 1112 the command prompt. 1113 1114 Global environment variables are those you use 1115 setenv/printenv to work with. To run a command stored 1116 in such a variable, you need to use the run command, 1117 and you must not use the '$' sign to access them. 1118 1119 To store commands and special characters in a 1120 variable, please use double quotation marks 1121 surrounding the whole text of the variable, instead 1122 of the backslashes before semicolons and special 1123 symbols. 1124 1125- Default Environment 1126 CONFIG_EXTRA_ENV_SETTINGS 1127 1128 Define this to contain any number of null terminated 1129 strings (variable = value pairs) that will be part of 1130 the default enviroment compiled into the boot image. 1131 1132 For example, place something like this in your 1133 board's config file: 1134 1135 #define CONFIG_EXTRA_ENV_SETTINGS \ 1136 "myvar1=value1\0" \ 1137 "myvar2=value2\0" 1138 1139 Warning: This method is based on knowledge about the 1140 internal format how the environment is stored by the 1141 U-Boot code. This is NOT an official, exported 1142 interface! Although it is unlikely that this format 1143 will change soon, but there is no guarantee either. 1144 You better know what you are doing here. 1145 1146 Note: overly (ab)use of the default environment is 1147 discouraged. Make sure to check other ways to preset 1148 the environment like the autoscript function or the 1149 boot command first. 1150 1151- Show boot progress 1152 CONFIG_SHOW_BOOT_PROGRESS 1153 1154 Defining this option allows to add some board- 1155 specific code (calling a user-provided function 1156 "show_boot_progress(int)") that enables you to show 1157 the system's boot progress on some display (for 1158 example, some LED's) on your board. At the moment, 1159 the following checkpoints are implemented: 1160 1161 Arg Where When 1162 1 common/cmd_bootm.c before attempting to boot an image 1163 -1 common/cmd_bootm.c Image header has bad magic number 1164 2 common/cmd_bootm.c Image header has correct magic number 1165 -2 common/cmd_bootm.c Image header has bad checksum 1166 3 common/cmd_bootm.c Image header has correct checksum 1167 -3 common/cmd_bootm.c Image data has bad checksum 1168 4 common/cmd_bootm.c Image data has correct checksum 1169 -4 common/cmd_bootm.c Image is for unsupported architecture 1170 5 common/cmd_bootm.c Architecture check OK 1171 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1172 6 common/cmd_bootm.c Image Type check OK 1173 -6 common/cmd_bootm.c gunzip uncompression error 1174 -7 common/cmd_bootm.c Unimplemented compression type 1175 7 common/cmd_bootm.c Uncompression OK 1176 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1177 8 common/cmd_bootm.c Image Type check OK 1178 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1179 9 common/cmd_bootm.c Start initial ramdisk verification 1180 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1181 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1182 10 common/cmd_bootm.c Ramdisk header is OK 1183 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1184 11 common/cmd_bootm.c Ramdisk data has correct checksum 1185 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1186 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1187 13 common/cmd_bootm.c Start multifile image verification 1188 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1189 15 common/cmd_bootm.c All preparation done, transferring control to OS 1190 1191 -1 common/cmd_doc.c Bad usage of "doc" command 1192 -1 common/cmd_doc.c No boot device 1193 -1 common/cmd_doc.c Unknown Chip ID on boot device 1194 -1 common/cmd_doc.c Read Error on boot device 1195 -1 common/cmd_doc.c Image header has bad magic number 1196 1197 -1 common/cmd_ide.c Bad usage of "ide" command 1198 -1 common/cmd_ide.c No boot device 1199 -1 common/cmd_ide.c Unknown boot device 1200 -1 common/cmd_ide.c Unknown partition table 1201 -1 common/cmd_ide.c Invalid partition type 1202 -1 common/cmd_ide.c Read Error on boot device 1203 -1 common/cmd_ide.c Image header has bad magic number 1204 1205 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1206 1207 1208Modem Support: 1209-------------- 1210 1211[so far only for SMDK2400 board] 1212 1213- Modem support endable: 1214 CONFIG_MODEM_SUPPORT 1215 1216- RTS/CTS Flow control enable: 1217 CONFIG_HWFLOW 1218 1219- Modem debug support: 1220 CONFIG_MODEM_SUPPORT_DEBUG 1221 1222 Enables debugging stuff (char screen[1024], dbg()) 1223 for modem support. Useful only with BDI2000. 1224 1225- General: 1226 1227 In the target system modem support is enabled when a 1228 specific key (key combination) is pressed during 1229 power-on. Otherwise U-Boot will boot normally 1230 (autoboot). The key_pressed() fuction is called from 1231 board_init(). Currently key_pressed() is a dummy 1232 function, returning 1 and thus enabling modem 1233 initialization. 1234 1235 If there are no modem init strings in the 1236 environment, U-Boot proceed to autoboot; the 1237 previous output (banner, info printfs) will be 1238 supressed, though. 1239 1240 See also: doc/README.Modem 1241 1242 1243 1244 1245Configuration Settings: 1246----------------------- 1247 1248- CFG_LONGHELP: Defined when you want long help messages included; 1249 undefine this when you're short of memory. 1250 1251- CFG_PROMPT: This is what U-Boot prints on the console to 1252 prompt for user input. 1253 1254- CFG_CBSIZE: Buffer size for input from the Console 1255 1256- CFG_PBSIZE: Buffer size for Console output 1257 1258- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1259 1260- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1261 the application (usually a Linux kernel) when it is 1262 booted 1263 1264- CFG_BAUDRATE_TABLE: 1265 List of legal baudrate settings for this board. 1266 1267- CFG_CONSOLE_INFO_QUIET 1268 Suppress display of console information at boot. 1269 1270- CFG_CONSOLE_IS_IN_ENV 1271 If the board specific function 1272 extern int overwrite_console (void); 1273 returns 1, the stdin, stderr and stdout are switched to the 1274 serial port, else the settings in the environment are used. 1275 1276- CFG_CONSOLE_OVERWRITE_ROUTINE 1277 Enable the call to overwrite_console(). 1278 1279- CFG_CONSOLE_ENV_OVERWRITE 1280 Enable overwrite of previous console environment settings. 1281 1282- CFG_MEMTEST_START, CFG_MEMTEST_END: 1283 Begin and End addresses of the area used by the 1284 simple memory test. 1285 1286- CFG_ALT_MEMTEST: 1287 Enable an alternate, more extensive memory test. 1288 1289- CFG_TFTP_LOADADDR: 1290 Default load address for network file downloads 1291 1292- CFG_LOADS_BAUD_CHANGE: 1293 Enable temporary baudrate change while serial download 1294 1295- CFG_SDRAM_BASE: 1296 Physical start address of SDRAM. _Must_ be 0 here. 1297 1298- CFG_MBIO_BASE: 1299 Physical start address of Motherboard I/O (if using a 1300 Cogent motherboard) 1301 1302- CFG_FLASH_BASE: 1303 Physical start address of Flash memory. 1304 1305- CFG_MONITOR_BASE: 1306 Physical start address of boot monitor code (set by 1307 make config files to be same as the text base address 1308 (TEXT_BASE) used when linking) - same as 1309 CFG_FLASH_BASE when booting from flash. 1310 1311- CFG_MONITOR_LEN: 1312 Size of memory reserved for monitor code 1313 1314- CFG_MALLOC_LEN: 1315 Size of DRAM reserved for malloc() use. 1316 1317- CFG_BOOTMAPSZ: 1318 Maximum size of memory mapped by the startup code of 1319 the Linux kernel; all data that must be processed by 1320 the Linux kernel (bd_info, boot arguments, eventually 1321 initrd image) must be put below this limit. 1322 1323- CFG_MAX_FLASH_BANKS: 1324 Max number of Flash memory banks 1325 1326- CFG_MAX_FLASH_SECT: 1327 Max number of sectors on a Flash chip 1328 1329- CFG_FLASH_ERASE_TOUT: 1330 Timeout for Flash erase operations (in ms) 1331 1332- CFG_FLASH_WRITE_TOUT: 1333 Timeout for Flash write operations (in ms) 1334 1335- CFG_DIRECT_FLASH_TFTP: 1336 1337 Enable TFTP transfers directly to flash memory; 1338 without this option such a download has to be 1339 performed in two steps: (1) download to RAM, and (2) 1340 copy from RAM to flash. 1341 1342 The two-step approach is usually more reliable, since 1343 you can check if the download worked before you erase 1344 the flash, but in some situations (when sytem RAM is 1345 too limited to allow for a tempory copy of the 1346 downloaded image) this option may be very useful. 1347 1348- CFG_FLASH_CFI: 1349 Define if the flash driver uses extra elements in the 1350 common flash structure for storing flash geometry 1351 1352The following definitions that deal with the placement and management 1353of environment data (variable area); in general, we support the 1354following configurations: 1355 1356- CFG_ENV_IS_IN_FLASH: 1357 1358 Define this if the environment is in flash memory. 1359 1360 a) The environment occupies one whole flash sector, which is 1361 "embedded" in the text segment with the U-Boot code. This 1362 happens usually with "bottom boot sector" or "top boot 1363 sector" type flash chips, which have several smaller 1364 sectors at the start or the end. For instance, such a 1365 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1366 such a case you would place the environment in one of the 1367 4 kB sectors - with U-Boot code before and after it. With 1368 "top boot sector" type flash chips, you would put the 1369 environment in one of the last sectors, leaving a gap 1370 between U-Boot and the environment. 1371 1372 - CFG_ENV_OFFSET: 1373 1374 Offset of environment data (variable area) to the 1375 beginning of flash memory; for instance, with bottom boot 1376 type flash chips the second sector can be used: the offset 1377 for this sector is given here. 1378 1379 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1380 1381 - CFG_ENV_ADDR: 1382 1383 This is just another way to specify the start address of 1384 the flash sector containing the environment (instead of 1385 CFG_ENV_OFFSET). 1386 1387 - CFG_ENV_SECT_SIZE: 1388 1389 Size of the sector containing the environment. 1390 1391 1392 b) Sometimes flash chips have few, equal sized, BIG sectors. 1393 In such a case you don't want to spend a whole sector for 1394 the environment. 1395 1396 - CFG_ENV_SIZE: 1397 1398 If you use this in combination with CFG_ENV_IS_IN_FLASH 1399 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1400 of this flash sector for the environment. This saves 1401 memory for the RAM copy of the environment. 1402 1403 It may also save flash memory if you decide to use this 1404 when your environment is "embedded" within U-Boot code, 1405 since then the remainder of the flash sector could be used 1406 for U-Boot code. It should be pointed out that this is 1407 STRONGLY DISCOURAGED from a robustness point of view: 1408 updating the environment in flash makes it always 1409 necessary to erase the WHOLE sector. If something goes 1410 wrong before the contents has been restored from a copy in 1411 RAM, your target system will be dead. 1412 1413 - CFG_ENV_ADDR_REDUND 1414 CFG_ENV_SIZE_REDUND 1415 1416 These settings describe a second storage area used to hold 1417 a redundand copy of the environment data, so that there is 1418 a valid backup copy in case there is a power failur during 1419 a "saveenv" operation. 1420 1421BE CAREFUL! Any changes to the flash layout, and some changes to the 1422source code will make it necessary to adapt <board>/u-boot.lds* 1423accordingly! 1424 1425 1426- CFG_ENV_IS_IN_NVRAM: 1427 1428 Define this if you have some non-volatile memory device 1429 (NVRAM, battery buffered SRAM) which you want to use for the 1430 environment. 1431 1432 - CFG_ENV_ADDR: 1433 - CFG_ENV_SIZE: 1434 1435 These two #defines are used to determin the memory area you 1436 want to use for environment. It is assumed that this memory 1437 can just be read and written to, without any special 1438 provision. 1439 1440BE CAREFUL! The first access to the environment happens quite early 1441in U-Boot initalization (when we try to get the setting of for the 1442console baudrate). You *MUST* have mappend your NVRAM area then, or 1443U-Boot will hang. 1444 1445Please note that even with NVRAM we still use a copy of the 1446environment in RAM: we could work on NVRAM directly, but we want to 1447keep settings there always unmodified except somebody uses "saveenv" 1448to save the current settings. 1449 1450 1451- CFG_ENV_IS_IN_EEPROM: 1452 1453 Use this if you have an EEPROM or similar serial access 1454 device and a driver for it. 1455 1456 - CFG_ENV_OFFSET: 1457 - CFG_ENV_SIZE: 1458 1459 These two #defines specify the offset and size of the 1460 environment area within the total memory of your EEPROM. 1461 1462 - CFG_I2C_EEPROM_ADDR: 1463 If defined, specified the chip address of the EEPROM device. 1464 The default address is zero. 1465 1466 - CFG_EEPROM_PAGE_WRITE_BITS: 1467 If defined, the number of bits used to address bytes in a 1468 single page in the EEPROM device. A 64 byte page, for example 1469 would require six bits. 1470 1471 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1472 If defined, the number of milliseconds to delay between 1473 page writes. The default is zero milliseconds. 1474 1475 - CFG_I2C_EEPROM_ADDR_LEN: 1476 The length in bytes of the EEPROM memory array address. Note 1477 that this is NOT the chip address length! 1478 1479 - CFG_EEPROM_SIZE: 1480 The size in bytes of the EEPROM device. 1481 1482 - CFG_I2C_EEPROM_ADDR: 1483 If defined, specified the chip address of the EEPROM device. 1484 The default address is zero. 1485 1486 - CFG_EEPROM_PAGE_WRITE_BITS: 1487 If defined, the number of bits used to address bytes in a 1488 single page in the EEPROM device. A 64 byte page, for example 1489 would require six bits. 1490 1491 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1492 If defined, the number of milliseconds to delay between 1493 page writes. The default is zero milliseconds. 1494 1495 - CFG_I2C_EEPROM_ADDR_LEN: 1496 The length in bytes of the EEPROM memory array address. Note 1497 that this is NOT the chip address length! 1498 1499 - CFG_EEPROM_SIZE: 1500 The size in bytes of the EEPROM device. 1501 1502- CFG_SPI_INIT_OFFSET 1503 1504 Defines offset to the initial SPI buffer area in DPRAM. The 1505 area is used at an early stage (ROM part) if the environment 1506 is configured to reside in the SPI EEPROM: We need a 520 byte 1507 scratch DPRAM area. It is used between the two initialization 1508 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1509 to be a good choice since it makes it far enough from the 1510 start of the data area as well as from the stack pointer. 1511 1512Please note that the environment is read-only as long as the monitor 1513has been relocated to RAM and a RAM copy of the environment has been 1514created; also, when using EEPROM you will have to use getenv_r() 1515until then to read environment variables. 1516 1517The environment is now protected by a CRC32 checksum. Before the 1518monitor is relocated into RAM, as a result of a bad CRC you will be 1519working with the compiled-in default environment - *silently*!!! 1520[This is necessary, because the first environment variable we need is 1521the "baudrate" setting for the console - if we have a bad CRC, we 1522don't have any device yet where we could complain.] 1523 1524Note: once the monitor has been relocated, then it will complain if 1525the default environment is used; a new CRC is computed as soon as you 1526use the "setenv" command to modify / delete / add any environment 1527variable [even when you try to delete a non-existing variable!]. 1528 1529Note2: you must edit your u-boot.lds file to reflect this 1530configuration. 1531 1532 1533Low Level (hardware related) configuration options: 1534 1535- CFG_CACHELINE_SIZE: 1536 Cache Line Size of the CPU. 1537 1538- CFG_DEFAULT_IMMR: 1539 Default address of the IMMR after system reset. 1540 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1541 to be able to adjust the position of the IMMR 1542 register after a reset. 1543 1544- Floppy Disk Support: 1545 CFG_FDC_DRIVE_NUMBER 1546 1547 the default drive number (default value 0) 1548 1549 CFG_ISA_IO_STRIDE 1550 1551 defines the spacing between fdc chipset registers 1552 (default value 1) 1553 1554 CFG_ISA_IO_OFFSET 1555 1556 defines the offset of register from address. It 1557 depends on which part of the data bus is connected to 1558 the fdc chipset. (default value 0) 1559 1560 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1561 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1562 default value. 1563 1564 if CFG_FDC_HW_INIT is defined, then the function 1565 fdc_hw_init() is called at the beginning of the FDC 1566 setup. fdc_hw_init() must be provided by the board 1567 source code. It is used to make hardware dependant 1568 initializations. 1569 1570- CFG_IMMR: Physical address of the Internal Memory Mapped 1571 Register; DO NOT CHANGE! (11-4) 1572 [MPC8xx systems only] 1573 1574- CFG_INIT_RAM_ADDR: 1575 1576 Start address of memory area tha can be used for 1577 initial data and stack; please note that this must be 1578 writable memory that is working WITHOUT special 1579 initialization, i. e. you CANNOT use normal RAM which 1580 will become available only after programming the 1581 memory controller and running certain initialization 1582 sequences. 1583 1584 U-Boot uses the following memory types: 1585 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1586 - MPC824X: data cache 1587 - PPC4xx: data cache 1588 1589- CFG_INIT_DATA_OFFSET: 1590 1591 Offset of the initial data structure in the memory 1592 area defined by CFG_INIT_RAM_ADDR. Usually 1593 CFG_INIT_DATA_OFFSET is chosen such that the initial 1594 data is located at the end of the available space 1595 (sometimes written as (CFG_INIT_RAM_END - 1596 CFG_INIT_DATA_SIZE), and the initial stack is just 1597 below that area (growing from (CFG_INIT_RAM_ADDR + 1598 CFG_INIT_DATA_OFFSET) downward. 1599 1600 Note: 1601 On the MPC824X (or other systems that use the data 1602 cache for initial memory) the address chosen for 1603 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1604 point to an otherwise UNUSED address space between 1605 the top of RAM and the start of the PCI space. 1606 1607- CFG_SIUMCR: SIU Module Configuration (11-6) 1608 1609- CFG_SYPCR: System Protection Control (11-9) 1610 1611- CFG_TBSCR: Time Base Status and Control (11-26) 1612 1613- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1614 1615- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1616 1617- CFG_SCCR: System Clock and reset Control Register (15-27) 1618 1619- CFG_OR_TIMING_SDRAM: 1620 SDRAM timing 1621 1622- CFG_MAMR_PTA: 1623 periodic timer for refresh 1624 1625- CFG_DER: Debug Event Register (37-47) 1626 1627- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1628 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1629 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1630 CFG_BR1_PRELIM: 1631 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1632 1633- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1634 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1635 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1636 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1637 1638- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1639 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1640 Machine Mode Register and Memory Periodic Timer 1641 Prescaler definitions (SDRAM timing) 1642 1643- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1644 enable I2C microcode relocation patch (MPC8xx); 1645 define relocation offset in DPRAM [DSP2] 1646 1647- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1648 enable SPI microcode relocation patch (MPC8xx); 1649 define relocation offset in DPRAM [SCC4] 1650 1651- CFG_USE_OSCCLK: 1652 Use OSCM clock mode on MBX8xx board. Be careful, 1653 wrong setting might damage your board. Read 1654 doc/README.MBX before setting this variable! 1655 1656Building the Software: 1657====================== 1658 1659Building U-Boot has been tested in native PPC environments (on a 1660PowerBook G3 running LinuxPPC 2000) and in cross environments 1661(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1662NetBSD 1.5 on x86). 1663 1664If you are not using a native PPC environment, it is assumed that you 1665have the GNU cross compiling tools available in your path and named 1666with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1667you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1668the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1669change it to: 1670 1671 CROSS_COMPILE = ppc_4xx- 1672 1673 1674U-Boot is intended to be simple to build. After installing the 1675sources you must configure U-Boot for one specific board type. This 1676is done by typing: 1677 1678 make NAME_config 1679 1680where "NAME_config" is the name of one of the existing 1681configurations; the following names are supported: 1682 1683 ADCIOP_config GTH_config TQM850L_config 1684 ADS860_config IP860_config TQM855L_config 1685 AR405_config IVML24_config TQM860L_config 1686 CANBT_config IVMS8_config WALNUT405_config 1687 CPCI405_config LANTEC_config cogent_common_config 1688 CPCIISER4_config MBX_config cogent_mpc8260_config 1689 CU824_config MBX860T_config cogent_mpc8xx_config 1690 ESTEEM192E_config RPXlite_config hermes_config 1691 ETX094_config RPXsuper_config hymod_config 1692 FADS823_config SM850_config lwmon_config 1693 FADS850SAR_config SPD823TS_config pcu_e_config 1694 FADS860T_config SXNI855T_config rsdproto_config 1695 FPS850L_config Sandpoint8240_config sbc8260_config 1696 GENIETV_config TQM823L_config PIP405_config 1697 GEN860T_config EBONY_config FPS860L_config 1698 1699Note: for some board special configuration names may exist; check if 1700 additional information is available from the board vendor; for 1701 instance, the TQM8xxL systems run normally at 50 MHz and use a 1702 SCC for 10baseT ethernet; there are also systems with 80 MHz 1703 CPU clock, and an optional Fast Ethernet module is available 1704 for CPU's with FEC. You can select such additional "features" 1705 when chosing the configuration, i. e. 1706 1707 make TQM860L_config 1708 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1709 1710 make TQM860L_FEC_config 1711 - will configure for a TQM860L at 50MHz with FEC for ethernet 1712 1713 make TQM860L_80MHz_config 1714 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1715 interface 1716 1717 make TQM860L_FEC_80MHz_config 1718 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1719 1720 make TQM823L_LCD_config 1721 - will configure for a TQM823L with U-Boot console on LCD 1722 1723 make TQM823L_LCD_80MHz_config 1724 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1725 1726 etc. 1727 1728 1729 1730Finally, type "make all", and you should get some working U-Boot 1731images ready for downlod to / installation on your system: 1732 1733- "u-boot.bin" is a raw binary image 1734- "u-boot" is an image in ELF binary format 1735- "u-boot.srec" is in Motorola S-Record format 1736 1737 1738Please be aware that the Makefiles assume you are using GNU make, so 1739for instance on NetBSD you might need to use "gmake" instead of 1740native "make". 1741 1742 1743If the system board that you have is not listed, then you will need 1744to port U-Boot to your hardware platform. To do this, follow these 1745steps: 1746 17471. Add a new configuration option for your board to the toplevel 1748 "Makefile", using the existing entries as examples. 17492. Create a new directory to hold your board specific code. Add any 1750 files you need. 17513. If you're porting U-Boot to a new CPU, then also create a new 1752 directory to hold your CPU specific code. Add any files you need. 17534. Run "make config_name" with your new name. 17545. Type "make", and you should get a working "u-boot.srec" file 1755 to be installed on your target system. 1756 [Of course, this last step is much harder than it sounds.] 1757 1758 1759Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1760============================================================== 1761 1762If you have modified U-Boot sources (for instance added a new board 1763or support for new devices, a new CPU, etc.) you are expected to 1764provide feedback to the other developers. The feedback normally takes 1765the form of a "patch", i. e. a context diff against a certain (latest 1766official or latest in CVS) version of U-Boot sources. 1767 1768But before you submit such a patch, please verify that your modifi- 1769cation did not break existing code. At least make sure that *ALL* of 1770the supported boards compile WITHOUT ANY compiler warnings. To do so, 1771just run the "MAKEALL" script, which will configure and build U-Boot 1772for ALL supported system. Be warned, this will take a while. You can 1773select which (cross) compiler to use py passing a `CROSS_COMPILE' 1774environment variable to the script, i. e. to use the cross tools from 1775MontaVista's Hard Hat Linux you can type 1776 1777 CROSS_COMPILE=ppc_8xx- MAKEALL 1778 1779or to build on a native PowerPC system you can type 1780 1781 CROSS_COMPILE=' ' MAKEALL 1782 1783See also "U-Boot Porting Guide" below. 1784 1785 1786 1787Monitor Commands - Overview: 1788============================ 1789 1790go - start application at address 'addr' 1791run - run commands in an environment variable 1792bootm - boot application image from memory 1793bootp - boot image via network using BootP/TFTP protocol 1794tftpboot- boot image via network using TFTP protocol 1795 and env variables "ipaddr" and "serverip" 1796 (and eventually "gatewayip") 1797rarpboot- boot image via network using RARP/TFTP protocol 1798diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1799loads - load S-Record file over serial line 1800loadb - load binary file over serial line (kermit mode) 1801md - memory display 1802mm - memory modify (auto-incrementing) 1803nm - memory modify (constant address) 1804mw - memory write (fill) 1805cp - memory copy 1806cmp - memory compare 1807crc32 - checksum calculation 1808imd - i2c memory display 1809imm - i2c memory modify (auto-incrementing) 1810inm - i2c memory modify (constant address) 1811imw - i2c memory write (fill) 1812icrc32 - i2c checksum calculation 1813iprobe - probe to discover valid I2C chip addresses 1814iloop - infinite loop on address range 1815isdram - print SDRAM configuration information 1816sspi - SPI utility commands 1817base - print or set address offset 1818printenv- print environment variables 1819setenv - set environment variables 1820saveenv - save environment variables to persistent storage 1821protect - enable or disable FLASH write protection 1822erase - erase FLASH memory 1823flinfo - print FLASH memory information 1824bdinfo - print Board Info structure 1825iminfo - print header information for application image 1826coninfo - print console devices and informations 1827ide - IDE sub-system 1828loop - infinite loop on address range 1829mtest - simple RAM test 1830icache - enable or disable instruction cache 1831dcache - enable or disable data cache 1832reset - Perform RESET of the CPU 1833echo - echo args to console 1834version - print monitor version 1835help - print online help 1836? - alias for 'help' 1837 1838 1839Monitor Commands - Detailed Description: 1840======================================== 1841 1842TODO. 1843 1844For now: just type "help <command>". 1845 1846 1847Environment Variables: 1848====================== 1849 1850U-Boot supports user configuration using Environment Variables which 1851can be made persistent by saving to Flash memory. 1852 1853Environment Variables are set using "setenv", printed using 1854"printenv", and saved to Flash using "saveenv". Using "setenv" 1855without a value can be used to delete a variable from the 1856environment. As long as you don't save the environment you are 1857working with an in-memory copy. In case the Flash area containing the 1858environment is erased by accident, a default environment is provided. 1859 1860Some configuration options can be set using Environment Variables: 1861 1862 baudrate - see CONFIG_BAUDRATE 1863 1864 bootdelay - see CONFIG_BOOTDELAY 1865 1866 bootcmd - see CONFIG_BOOTCOMMAND 1867 1868 bootargs - Boot arguments when booting an RTOS image 1869 1870 bootfile - Name of the image to load with TFTP 1871 1872 autoload - if set to "no" (any string beginning with 'n'), 1873 "bootp" will just load perform a lookup of the 1874 configuration from the BOOTP server, but not try to 1875 load any image using TFTP 1876 1877 autostart - if set to "yes", an image loaded using the "bootp", 1878 "rarpboot", "tftpboot" or "diskboot" commands will 1879 be automatically started (by internally calling 1880 "bootm") 1881 1882 initrd_high - restrict positioning of initrd images: 1883 If this variable is not set, initrd images will be 1884 copied to the highest possible address in RAM; this 1885 is usually what you want since it allows for 1886 maximum initrd size. If for some reason you want to 1887 make sure that the initrd image is loaded below the 1888 CFG_BOOTMAPSZ limit, you can set this environment 1889 variable to a value of "no" or "off" or "0". 1890 Alternatively, you can set it to a maximum upper 1891 address to use (U-Boot will still check that it 1892 does not overwrite the U-Boot stack and data). 1893 1894 For instance, when you have a system with 16 MB 1895 RAM, and want to reseve 4 MB from use by Linux, 1896 you can do this by adding "mem=12M" to the value of 1897 the "bootargs" variable. However, now you must make 1898 sure, that the initrd image is placed in the first 1899 12 MB as well - this can be done with 1900 1901 setenv initrd_high 00c00000 1902 1903 ipaddr - IP address; needed for tftpboot command 1904 1905 loadaddr - Default load address for commands like "bootp", 1906 "rarpboot", "tftpboot" or "diskboot" 1907 1908 loads_echo - see CONFIG_LOADS_ECHO 1909 1910 serverip - TFTP server IP address; needed for tftpboot command 1911 1912 bootretry - see CONFIG_BOOT_RETRY_TIME 1913 1914 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1915 1916 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1917 1918 1919The following environment variables may be used and automatically 1920updated by the network boot commands ("bootp" and "rarpboot"), 1921depending the information provided by your boot server: 1922 1923 bootfile - see above 1924 dnsip - IP address of your Domain Name Server 1925 gatewayip - IP address of the Gateway (Router) to use 1926 hostname - Target hostname 1927 ipaddr - see above 1928 netmask - Subnet Mask 1929 rootpath - Pathname of the root filesystem on the NFS server 1930 serverip - see above 1931 1932 1933There are two special Environment Variables: 1934 1935 serial# - contains hardware identification information such 1936 as type string and/or serial number 1937 ethaddr - Ethernet address 1938 1939These variables can be set only once (usually during manufacturing of 1940the board). U-Boot refuses to delete or overwrite these variables 1941once they have been set once. 1942 1943 1944Please note that changes to some configuration parameters may take 1945only effect after the next boot (yes, that's just like Windoze :-). 1946 1947 1948Note for Redundant Ethernet Interfaces: 1949======================================= 1950 1951Some boards come with redundand ethernet interfaces; U-Boot supports 1952such configurations and is capable of automatic selection of a 1953"working" interface when needed. MAC assignemnt works as follows: 1954 1955Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1956MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1957"eth1addr" (=>eth1), "eth2addr", ... 1958 1959If the network interface stores some valid MAC address (for instance 1960in SROM), this is used as default address if there is NO correspon- 1961ding setting in the environment; if the corresponding environment 1962variable is set, this overrides the settings in the card; that means: 1963 1964o If the SROM has a valid MAC address, and there is no address in the 1965 environment, the SROM's address is used. 1966 1967o If there is no valid address in the SROM, and a definition in the 1968 environment exists, then the value from the environment variable is 1969 used. 1970 1971o If both the SROM and the environment contain a MAC address, and 1972 both addresses are the same, this MAC address is used. 1973 1974o If both the SROM and the environment contain a MAC address, and the 1975 addresses differ, the value from the environment is used and a 1976 warning is printed. 1977 1978o If neither SROM nor the environment contain a MAC address, an error 1979 is raised. 1980 1981 1982 1983Image Formats: 1984============== 1985 1986The "boot" commands of this monitor operate on "image" files which 1987can be basicly anything, preceeded by a special header; see the 1988definitions in include/image.h for details; basicly, the header 1989defines the following image properties: 1990 1991* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 1992 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 1993 LynxOS, pSOS, QNX; 1994 Currently supported: Linux, NetBSD, VxWorks, QNX). 1995* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 1996 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 1997 Currently supported: PowerPC). 1998* Compression Type (Provisions for uncompressed, gzip, bzip2; 1999 Currently supported: uncompressed, gzip). 2000* Load Address 2001* Entry Point 2002* Image Name 2003* Image Timestamp 2004 2005The header is marked by a special Magic Number, and both the header 2006and the data portions of the image are secured against corruption by 2007CRC32 checksums. 2008 2009 2010Linux Support: 2011============== 2012 2013Although U-Boot should support any OS or standalone application 2014easily, Linux has always been in the focus during the design of 2015U-Boot. 2016 2017U-Boot includes many features that so far have been part of some 2018special "boot loader" code within the Linux kernel. Also, any 2019"initrd" images to be used are no longer part of one big Linux image; 2020instead, kernel and "initrd" are separate images. This implementation 2021serves serveral purposes: 2022 2023- the same features can be used for other OS or standalone 2024 applications (for instance: using compressed images to reduce the 2025 Flash memory footprint) 2026 2027- it becomes much easier to port new Linux kernel versions because 2028 lots of low-level, hardware dependend stuff are done by U-Boot 2029 2030- the same Linux kernel image can now be used with different "initrd" 2031 images; of course this also means that different kernel images can 2032 be run with the same "initrd". This makes testing easier (you don't 2033 have to build a new "zImage.initrd" Linux image when you just 2034 change a file in your "initrd"). Also, a field-upgrade of the 2035 software is easier now. 2036 2037 2038Linux HOWTO: 2039============ 2040 2041Porting Linux to U-Boot based systems: 2042--------------------------------------- 2043 2044U-Boot cannot save you from doing all the necessary modifications to 2045configure the Linux device drivers for use with your target hardware 2046(no, we don't intend to provide a full virtual machine interface to 2047Linux :-). 2048 2049But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2050 2051Just make sure your machine specific header file (for instance 2052include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2053Information structure as we define in include/u-boot.h, and make 2054sure that your definition of IMAP_ADDR uses the same value as your 2055U-Boot configuration in CFG_IMMR. 2056 2057 2058Configuring the Linux kernel: 2059----------------------------- 2060 2061No specific requirements for U-Boot. Make sure you have some root 2062device (initial ramdisk, NFS) for your target system. 2063 2064 2065Building a Linux Image: 2066----------------------- 2067 2068With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2069not used. If you use recent kernel source, a new build target 2070"uImage" will exist which automatically builds an image usable by 2071U-Boot. Most older kernels also have support for a "pImage" target, 2072which was introduced for our predecessor project PPCBoot and uses a 2073100% compatible format. 2074 2075Example: 2076 2077 make TQM850L_config 2078 make oldconfig 2079 make dep 2080 make uImage 2081 2082The "uImage" build target uses a special tool (in 'tools/mkimage') to 2083encapsulate a compressed Linux kernel image with header information, 2084CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2085 2086* build a standard "vmlinux" kernel image (in ELF binary format): 2087 2088* convert the kernel into a raw binary image: 2089 2090 ${CROSS_COMPILE}-objcopy -O binary \ 2091 -R .note -R .comment \ 2092 -S vmlinux linux.bin 2093 2094* compress the binary image: 2095 2096 gzip -9 linux.bin 2097 2098* package compressed binary image for U-Boot: 2099 2100 mkimage -A ppc -O linux -T kernel -C gzip \ 2101 -a 0 -e 0 -n "Linux Kernel Image" \ 2102 -d linux.bin.gz uImage 2103 2104 2105The "mkimage" tool can also be used to create ramdisk images for use 2106with U-Boot, either separated from the Linux kernel image, or 2107combined into one file. "mkimage" encapsulates the images with a 64 2108byte header containing information about target architecture, 2109operating system, image type, compression method, entry points, time 2110stamp, CRC32 checksums, etc. 2111 2112"mkimage" can be called in two ways: to verify existing images and 2113print the header information, or to build new images. 2114 2115In the first form (with "-l" option) mkimage lists the information 2116contained in the header of an existing U-Boot image; this includes 2117checksum verification: 2118 2119 tools/mkimage -l image 2120 -l ==> list image header information 2121 2122The second form (with "-d" option) is used to build a U-Boot image 2123from a "data file" which is used as image payload: 2124 2125 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2126 -n name -d data_file image 2127 -A ==> set architecture to 'arch' 2128 -O ==> set operating system to 'os' 2129 -T ==> set image type to 'type' 2130 -C ==> set compression type 'comp' 2131 -a ==> set load address to 'addr' (hex) 2132 -e ==> set entry point to 'ep' (hex) 2133 -n ==> set image name to 'name' 2134 -d ==> use image data from 'datafile' 2135 2136Right now, all Linux kernels use the same load address (0x00000000), 2137but the entry point address depends on the kernel version: 2138 2139- 2.2.x kernels have the entry point at 0x0000000C, 2140- 2.3.x and later kernels have the entry point at 0x00000000. 2141 2142So a typical call to build a U-Boot image would read: 2143 2144 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2145 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2146 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2147 > examples/uImage.TQM850L 2148 Image Name: 2.4.4 kernel for TQM850L 2149 Created: Wed Jul 19 02:34:59 2000 2150 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2151 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2152 Load Address: 0x00000000 2153 Entry Point: 0x00000000 2154 2155To verify the contents of the image (or check for corruption): 2156 2157 -> tools/mkimage -l examples/uImage.TQM850L 2158 Image Name: 2.4.4 kernel for TQM850L 2159 Created: Wed Jul 19 02:34:59 2000 2160 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2161 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2162 Load Address: 0x00000000 2163 Entry Point: 0x00000000 2164 2165NOTE: for embedded systems where boot time is critical you can trade 2166speed for memory and install an UNCOMPRESSED image instead: this 2167needs more space in Flash, but boots much faster since it does not 2168need to be uncompressed: 2169 2170 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2171 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2172 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2173 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2174 > examples/uImage.TQM850L-uncompressed 2175 Image Name: 2.4.4 kernel for TQM850L 2176 Created: Wed Jul 19 02:34:59 2000 2177 Image Type: PowerPC Linux Kernel Image (uncompressed) 2178 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2179 Load Address: 0x00000000 2180 Entry Point: 0x00000000 2181 2182 2183Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2184when your kernel is intended to use an initial ramdisk: 2185 2186 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2187 > -A ppc -O linux -T ramdisk -C gzip \ 2188 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2189 Image Name: Simple Ramdisk Image 2190 Created: Wed Jan 12 14:01:50 2000 2191 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2192 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2193 Load Address: 0x00000000 2194 Entry Point: 0x00000000 2195 2196 2197Installing a Linux Image: 2198------------------------- 2199 2200To downloading a U-Boot image over the serial (console) interface, 2201you must convert the image to S-Record format: 2202 2203 objcopy -I binary -O srec examples/image examples/image.srec 2204 2205The 'objcopy' does not understand the information in the U-Boot 2206image header, so the resulting S-Record file will be relative to 2207address 0x00000000. To load it to a given address, you need to 2208specify the target address as 'offset' parameter with the 'loads' 2209command. 2210 2211Example: install the image to address 0x40100000 (which on the 2212TQM8xxL is in the first Flash bank): 2213 2214 => erase 40100000 401FFFFF 2215 2216 .......... done 2217 Erased 8 sectors 2218 2219 => loads 40100000 2220 ## Ready for S-Record download ... 2221 ~>examples/image.srec 2222 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2223 ... 2224 15989 15990 15991 15992 2225 [file transfer complete] 2226 [connected] 2227 ## Start Addr = 0x00000000 2228 2229 2230You can check the success of the download using the 'iminfo' command; 2231this includes a checksum verification so you can be sure no data 2232corruption happened: 2233 2234 => imi 40100000 2235 2236 ## Checking Image at 40100000 ... 2237 Image Name: 2.2.13 for initrd on TQM850L 2238 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2239 Data Size: 335725 Bytes = 327 kB = 0 MB 2240 Load Address: 00000000 2241 Entry Point: 0000000c 2242 Verifying Checksum ... OK 2243 2244 2245 2246Boot Linux: 2247----------- 2248 2249The "bootm" command is used to boot an application that is stored in 2250memory (RAM or Flash). In case of a Linux kernel image, the contents 2251of the "bootargs" environment variable is passed to the kernel as 2252parameters. You can check and modify this variable using the 2253"printenv" and "setenv" commands: 2254 2255 2256 => printenv bootargs 2257 bootargs=root=/dev/ram 2258 2259 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2260 2261 => printenv bootargs 2262 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2263 2264 => bootm 40020000 2265 ## Booting Linux kernel at 40020000 ... 2266 Image Name: 2.2.13 for NFS on TQM850L 2267 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2268 Data Size: 381681 Bytes = 372 kB = 0 MB 2269 Load Address: 00000000 2270 Entry Point: 0000000c 2271 Verifying Checksum ... OK 2272 Uncompressing Kernel Image ... OK 2273 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 2274 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2275 time_init: decrementer frequency = 187500000/60 2276 Calibrating delay loop... 49.77 BogoMIPS 2277 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2278 ... 2279 2280If you want to boot a Linux kernel with initial ram disk, you pass 2281the memory addreses of both the kernel and the initrd image (PPBCOOT 2282format!) to the "bootm" command: 2283 2284 => imi 40100000 40200000 2285 2286 ## Checking Image at 40100000 ... 2287 Image Name: 2.2.13 for initrd on TQM850L 2288 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2289 Data Size: 335725 Bytes = 327 kB = 0 MB 2290 Load Address: 00000000 2291 Entry Point: 0000000c 2292 Verifying Checksum ... OK 2293 2294 ## Checking Image at 40200000 ... 2295 Image Name: Simple Ramdisk Image 2296 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2297 Data Size: 566530 Bytes = 553 kB = 0 MB 2298 Load Address: 00000000 2299 Entry Point: 00000000 2300 Verifying Checksum ... OK 2301 2302 => bootm 40100000 40200000 2303 ## Booting Linux kernel at 40100000 ... 2304 Image Name: 2.2.13 for initrd on TQM850L 2305 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2306 Data Size: 335725 Bytes = 327 kB = 0 MB 2307 Load Address: 00000000 2308 Entry Point: 0000000c 2309 Verifying Checksum ... OK 2310 Uncompressing Kernel Image ... OK 2311 ## Loading RAMDisk Image at 40200000 ... 2312 Image Name: Simple Ramdisk Image 2313 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2314 Data Size: 566530 Bytes = 553 kB = 0 MB 2315 Load Address: 00000000 2316 Entry Point: 00000000 2317 Verifying Checksum ... OK 2318 Loading Ramdisk ... OK 2319 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 2320 Boot arguments: root=/dev/ram 2321 time_init: decrementer frequency = 187500000/60 2322 Calibrating delay loop... 49.77 BogoMIPS 2323 ... 2324 RAMDISK: Compressed image found at block 0 2325 VFS: Mounted root (ext2 filesystem). 2326 2327 bash# 2328 2329 2330Standalone HOWTO: 2331================= 2332 2333One of the features of U-Boot is that you can dynamically load and 2334run "standalone" applications, which can use some resources of 2335U-Boot like console I/O functions or interrupt services. 2336 2337Two simple examples are included with the sources: 2338 2339"Hello World" Demo: 2340------------------- 2341 2342'examples/hello_world.c' contains a small "Hello World" Demo 2343application; it is automatically compiled when you build U-Boot. 2344It's configured to run at address 0x00040004, so you can play with it 2345like that: 2346 2347 => loads 2348 ## Ready for S-Record download ... 2349 ~>examples/hello_world.srec 2350 1 2 3 4 5 6 7 8 9 10 11 ... 2351 [file transfer complete] 2352 [connected] 2353 ## Start Addr = 0x00040004 2354 2355 => go 40004 Hello World! This is a test. 2356 ## Starting application at 0x00040004 ... 2357 Hello World 2358 argc = 7 2359 argv[0] = "40004" 2360 argv[1] = "Hello" 2361 argv[2] = "World!" 2362 argv[3] = "This" 2363 argv[4] = "is" 2364 argv[5] = "a" 2365 argv[6] = "test." 2366 argv[7] = "<NULL>" 2367 Hit any key to exit ... 2368 2369 ## Application terminated, rc = 0x0 2370 2371Another example, which demonstrates how to register a CPM interrupt 2372handler with the U-Boot code, can be found in 'examples/timer.c'. 2373Here, a CPM timer is set up to generate an interrupt every second. 2374The interrupt service routine is trivial, just printing a '.' 2375character, but this is just a demo program. The application can be 2376controlled by the following keys: 2377 2378 ? - print current values og the CPM Timer registers 2379 b - enable interrupts and start timer 2380 e - stop timer and disable interrupts 2381 q - quit application 2382 2383 => loads 2384 ## Ready for S-Record download ... 2385 ~>examples/timer.srec 2386 1 2 3 4 5 6 7 8 9 10 11 ... 2387 [file transfer complete] 2388 [connected] 2389 ## Start Addr = 0x00040004 2390 2391 => go 40004 2392 ## Starting application at 0x00040004 ... 2393 TIMERS=0xfff00980 2394 Using timer 1 2395 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2396 2397Hit 'b': 2398 [q, b, e, ?] Set interval 1000000 us 2399 Enabling timer 2400Hit '?': 2401 [q, b, e, ?] ........ 2402 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2403Hit '?': 2404 [q, b, e, ?] . 2405 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2406Hit '?': 2407 [q, b, e, ?] . 2408 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2409Hit '?': 2410 [q, b, e, ?] . 2411 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2412Hit 'e': 2413 [q, b, e, ?] ...Stopping timer 2414Hit 'q': 2415 [q, b, e, ?] ## Application terminated, rc = 0x0 2416 2417 2418NetBSD Notes: 2419============= 2420 2421Starting at version 0.9.2, U-Boot supports NetBSD both as host 2422(build U-Boot) and target system (boots NetBSD/mpc8xx). 2423 2424Building requires a cross environment; it is known to work on 2425NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2426need gmake since the Makefiles are not compatible with BSD make). 2427Note that the cross-powerpc package does not install include files; 2428attempting to build U-Boot will fail because <machine/ansi.h> is 2429missing. This file has to be installed and patched manually: 2430 2431 # cd /usr/pkg/cross/powerpc-netbsd/include 2432 # mkdir powerpc 2433 # ln -s powerpc machine 2434 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2435 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2436 2437Native builds *don't* work due to incompatibilities between native 2438and U-Boot include files. 2439 2440Booting assumes that (the first part of) the image booted is a 2441stage-2 loader which in turn loads and then invokes the kernel 2442proper. Loader sources will eventually appear in the NetBSD source 2443tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2444meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2445details. 2446 2447 2448Implementation Internals: 2449========================= 2450 2451The following is not intended to be a complete description of every 2452implementation detail. However, it should help to understand the 2453inner workings of U-Boot and make it easier to port it to custom 2454hardware. 2455 2456 2457Initial Stack, Global Data: 2458--------------------------- 2459 2460The implementation of U-Boot is complicated by the fact that U-Boot 2461starts running out of ROM (flash memory), usually without access to 2462system RAM (because the memory controller is not initialized yet). 2463This means that we don't have writable Data or BSS segments, and BSS 2464is not initialized as zero. To be able to get a C environment working 2465at all, we have to allocate at least a minimal stack. Implementation 2466options for this are defined and restricted by the CPU used: Some CPU 2467models provide on-chip memory (like the IMMR area on MPC8xx and 2468MPC826x processors), on others (parts of) the data cache can be 2469locked as (mis-) used as memory, etc. 2470 2471It is essential to remember this, since it has some impact on the C 2472code for the initialization procedures: 2473 2474* Initialized global data (data segment) is read-only. Do not attempt 2475 to write it. 2476 2477* Do not use any unitialized global data (or implicitely initialized 2478 as zero data - BSS segment) at all - this is undefined, initiali- 2479 zation is performed later (when relocationg to RAM). 2480 2481* Stack space is very limited. Avoid big data buffers or things like 2482 that. 2483 2484Having only the stack as writable memory limits means we cannot use 2485normal global data to share information beween the code. But it 2486turned out that the implementation of U-Boot can be greatly 2487simplified by making a global data structure (gd_t) available to all 2488functions. We could pass a pointer to this data as argument to _all_ 2489functions, but this would bloat the code. Instead we use a feature of 2490the GCC compiler (Global Register Variables) to share the data: we 2491place a pointer (gd) to the global data into a register which we 2492reserve for this purpose. 2493 2494When chosing a register for such a purpose we are restricted by the 2495relevant (E)ABI specifications for the current architecture, and by 2496GCC's implementation. 2497 2498For PowerPC, the following registers have specific use: 2499 R1: stack pointer 2500 R2: TOC pointer 2501 R3-R4: parameter passing and return values 2502 R5-R10: parameter passing 2503 R13: small data area pointer 2504 R30: GOT pointer 2505 R31: frame pointer 2506 2507 (U-Boot also uses R14 as internal GOT pointer.) 2508 2509 ==> U-Boot will use R29 to hold a pointer to the global data 2510 2511 Note: on PPC, we could use a static initializer (since the 2512 address of the global data structure is known at compile time), 2513 but it turned out that reserving a register results in somewhat 2514 smaller code - although the code savings are not that big (on 2515 average for all boards 752 bytes for the whole U-Boot image, 2516 624 text + 127 data). 2517 2518On ARM, the following registers are used: 2519 2520 R0: function argument word/integer result 2521 R1-R3: function argument word 2522 R9: GOT pointer 2523 R10: stack limit (used only if stack checking if enabled) 2524 R11: argument (frame) pointer 2525 R12: temporary workspace 2526 R13: stack pointer 2527 R14: link register 2528 R15: program counter 2529 2530 ==> U-Boot will use R8 to hold a pointer to the global data 2531 2532 2533 2534Memory Management: 2535------------------ 2536 2537U-Boot runs in system state and uses physical addresses, i.e. the 2538MMU is not used either for address mapping nor for memory protection. 2539 2540The available memory is mapped to fixed addresses using the memory 2541controller. In this process, a contiguous block is formed for each 2542memory type (Flash, SDRAM, SRAM), even when it consists of several 2543physical memory banks. 2544 2545U-Boot is installed in the first 128 kB of the first Flash bank (on 2546TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2547booting and sizing and initializing DRAM, the code relocates itself 2548to the upper end of DRAM. Immediately below the U-Boot code some 2549memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2550configuration setting]. Below that, a structure with global Board 2551Info data is placed, followed by the stack (growing downward). 2552 2553Additionally, some exception handler code is copied to the low 8 kB 2554of DRAM (0x00000000 ... 0x00001FFF). 2555 2556So a typical memory configuration with 16 MB of DRAM could look like 2557this: 2558 2559 0x0000 0000 Exception Vector code 2560 : 2561 0x0000 1FFF 2562 0x0000 2000 Free for Application Use 2563 : 2564 : 2565 2566 : 2567 : 2568 0x00FB FF20 Monitor Stack (Growing downward) 2569 0x00FB FFAC Board Info Data and permanent copy of global data 2570 0x00FC 0000 Malloc Arena 2571 : 2572 0x00FD FFFF 2573 0x00FE 0000 RAM Copy of Monitor Code 2574 ... eventually: LCD or video framebuffer 2575 ... eventually: pRAM (Protected RAM - unchanged by reset) 2576 0x00FF FFFF [End of RAM] 2577 2578 2579System Initialization: 2580---------------------- 2581 2582In the reset configuration, U-Boot starts at the reset entry point 2583(on most PowerPC systens at address 0x00000100). Because of the reset 2584configuration for CS0# this is a mirror of the onboard Flash memory. 2585To be able to re-map memory U-Boot then jumps to it's link address. 2586To be able to implement the initialization code in C, a (small!) 2587initial stack is set up in the internal Dual Ported RAM (in case CPUs 2588which provide such a feature like MPC8xx or MPC8260), or in a locked 2589part of the data cache. After that, U-Boot initializes the CPU core, 2590the caches and the SIU. 2591 2592Next, all (potentially) available memory banks are mapped using a 2593preliminary mapping. For example, we put them on 512 MB boundaries 2594(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2595on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2596programmed for SDRAM access. Using the temporary configuration, a 2597simple memory test is run that determines the size of the SDRAM 2598banks. 2599 2600When there is more than one SDRAM bank, and the banks are of 2601different size, the larger is mapped first. For equal size, the first 2602bank (CS2#) is mapped first. The first mapping is always for address 26030x00000000, with any additional banks following immediately to create 2604contiguous memory starting from 0. 2605 2606Then, the monitor installs itself at the upper end of the SDRAM area 2607and allocates memory for use by malloc() and for the global Board 2608Info data; also, the exception vector code is copied to the low RAM 2609pages, and the final stack is set up. 2610 2611Only after this relocation will you have a "normal" C environment; 2612until that you are restricted in several ways, mostly because you are 2613running from ROM, and because the code will have to be relocated to a 2614new address in RAM. 2615 2616 2617U-Boot Porting Guide: 2618---------------------- 2619 2620[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2621list, Octover 2002] 2622 2623 2624int main (int argc, char *argv[]) 2625{ 2626 sighandler_t no_more_time; 2627 2628 signal (SIGALRM, no_more_time); 2629 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2630 2631 if (available_money > available_manpower) { 2632 pay consultant to port U-Boot; 2633 return 0; 2634 } 2635 2636 Download latest U-Boot source; 2637 2638 if (clueless) { 2639 email ("Hi, I am new to U-Boot, how do I get started?"); 2640 } 2641 2642 while (learning) { 2643 Read the README file in the top level directory; 2644 Read http://www.denx.de/re/DPLG.html 2645 Read the source, Luke; 2646 } 2647 2648 if (available_money > toLocalCurrency ($2500)) { 2649 Buy a BDI2000; 2650 } else { 2651 Add a lot of aggravation and time; 2652 } 2653 2654 Create your own board support subdirectory; 2655 2656 while (!running) { 2657 do { 2658 Add / modify source code; 2659 } until (compiles); 2660 Debug; 2661 if (clueless) 2662 email ("Hi, I am having problems..."); 2663 } 2664 Send patch file to Wolfgang; 2665 2666 return 0; 2667} 2668 2669void no_more_time (int sig) 2670{ 2671 hire_a_guru(); 2672} 2673 2674 2675 2676Coding Standards: 2677----------------- 2678 2679All contributions to U-Boot should conform to the Linux kernel 2680coding style; see the file "Documentation/CodingStyle" in your Linux 2681kernel source directory. 2682 2683Please note that U-Boot is implemented in C (and to some small parts 2684in Assembler); no C++ is used, so please do not use C++ style 2685comments (//) in your code. 2686 2687Submissions which do not conform to the standards may be returned 2688with a request to reformat the changes. 2689 2690 2691Submitting Patches: 2692------------------- 2693 2694Since the number of patches for U-Boot is growing, we need to 2695establish some rules. Submissions which do not conform to these rules 2696may be rejected, even when they contain important and valuable stuff. 2697 2698 2699When you send a patch, please include the following information with 2700it: 2701 2702* For bug fixes: a description of the bug and how your patch fixes 2703 this bug. Please try to include a way of demonstrating that the 2704 patch actually fixes something. 2705 2706* For new features: a description of the feature and your 2707 implementation. 2708 2709* A CHANGELOG entry as plaintext (separate from the patch) 2710 2711* For major contributions, your entry to the CREDITS file 2712 2713* When you add support for a new board, don't forget to add this 2714 board to the MAKEALL script, too. 2715 2716* If your patch adds new configuration options, don't forget to 2717 document these in the README file. 2718 2719* The patch itself. If you are accessing the CVS repository use "cvs 2720 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2721 version of diff does not support these options, then get the latest 2722 version of GNU diff. 2723 2724 We accept patches as plain text, MIME attachments or as uuencoded 2725 gzipped text. 2726 2727Notes: 2728 2729* Before sending the patch, run the MAKEALL script on your patched 2730 source tree and make sure that no errors or warnings are reported 2731 for any of the boards. 2732 2733* Keep your modifications to the necessary minimum: A patch 2734 containing several unrelated changes or arbitrary reformats will be 2735 returned with a request to re-formatting / split it. 2736 2737* If you modify existing code, make sure that your new code does not 2738 add to the memory footprint of the code ;-) Small is beautiful! 2739 When adding new features, these should compile conditionally only 2740 (using #ifdef), and the resulting code with the new feature 2741 disabled must not need more memory than the old code without your 2742 modification. 2743