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 1656- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1657 Offset of the bootmode word in DPRAM used by post 1658 (Power On Self Tests). This definition overrides 1659 #define'd default value in commproc.h resp. 1660 cpm_8260.h. 1661 1662Building the Software: 1663====================== 1664 1665Building U-Boot has been tested in native PPC environments (on a 1666PowerBook G3 running LinuxPPC 2000) and in cross environments 1667(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1668NetBSD 1.5 on x86). 1669 1670If you are not using a native PPC environment, it is assumed that you 1671have the GNU cross compiling tools available in your path and named 1672with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1673you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1674the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1675change it to: 1676 1677 CROSS_COMPILE = ppc_4xx- 1678 1679 1680U-Boot is intended to be simple to build. After installing the 1681sources you must configure U-Boot for one specific board type. This 1682is done by typing: 1683 1684 make NAME_config 1685 1686where "NAME_config" is the name of one of the existing 1687configurations; the following names are supported: 1688 1689 ADCIOP_config GTH_config TQM850L_config 1690 ADS860_config IP860_config TQM855L_config 1691 AR405_config IVML24_config TQM860L_config 1692 CANBT_config IVMS8_config WALNUT405_config 1693 CPCI405_config LANTEC_config cogent_common_config 1694 CPCIISER4_config MBX_config cogent_mpc8260_config 1695 CU824_config MBX860T_config cogent_mpc8xx_config 1696 ESTEEM192E_config RPXlite_config hermes_config 1697 ETX094_config RPXsuper_config hymod_config 1698 FADS823_config SM850_config lwmon_config 1699 FADS850SAR_config SPD823TS_config pcu_e_config 1700 FADS860T_config SXNI855T_config rsdproto_config 1701 FPS850L_config Sandpoint8240_config sbc8260_config 1702 GENIETV_config TQM823L_config PIP405_config 1703 GEN860T_config EBONY_config FPS860L_config 1704 1705Note: for some board special configuration names may exist; check if 1706 additional information is available from the board vendor; for 1707 instance, the TQM8xxL systems run normally at 50 MHz and use a 1708 SCC for 10baseT ethernet; there are also systems with 80 MHz 1709 CPU clock, and an optional Fast Ethernet module is available 1710 for CPU's with FEC. You can select such additional "features" 1711 when chosing the configuration, i. e. 1712 1713 make TQM860L_config 1714 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1715 1716 make TQM860L_FEC_config 1717 - will configure for a TQM860L at 50MHz with FEC for ethernet 1718 1719 make TQM860L_80MHz_config 1720 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1721 interface 1722 1723 make TQM860L_FEC_80MHz_config 1724 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1725 1726 make TQM823L_LCD_config 1727 - will configure for a TQM823L with U-Boot console on LCD 1728 1729 make TQM823L_LCD_80MHz_config 1730 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1731 1732 etc. 1733 1734 1735 1736Finally, type "make all", and you should get some working U-Boot 1737images ready for downlod to / installation on your system: 1738 1739- "u-boot.bin" is a raw binary image 1740- "u-boot" is an image in ELF binary format 1741- "u-boot.srec" is in Motorola S-Record format 1742 1743 1744Please be aware that the Makefiles assume you are using GNU make, so 1745for instance on NetBSD you might need to use "gmake" instead of 1746native "make". 1747 1748 1749If the system board that you have is not listed, then you will need 1750to port U-Boot to your hardware platform. To do this, follow these 1751steps: 1752 17531. Add a new configuration option for your board to the toplevel 1754 "Makefile", using the existing entries as examples. 17552. Create a new directory to hold your board specific code. Add any 1756 files you need. 17573. If you're porting U-Boot to a new CPU, then also create a new 1758 directory to hold your CPU specific code. Add any files you need. 17594. Run "make config_name" with your new name. 17605. Type "make", and you should get a working "u-boot.srec" file 1761 to be installed on your target system. 1762 [Of course, this last step is much harder than it sounds.] 1763 1764 1765Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1766============================================================== 1767 1768If you have modified U-Boot sources (for instance added a new board 1769or support for new devices, a new CPU, etc.) you are expected to 1770provide feedback to the other developers. The feedback normally takes 1771the form of a "patch", i. e. a context diff against a certain (latest 1772official or latest in CVS) version of U-Boot sources. 1773 1774But before you submit such a patch, please verify that your modifi- 1775cation did not break existing code. At least make sure that *ALL* of 1776the supported boards compile WITHOUT ANY compiler warnings. To do so, 1777just run the "MAKEALL" script, which will configure and build U-Boot 1778for ALL supported system. Be warned, this will take a while. You can 1779select which (cross) compiler to use py passing a `CROSS_COMPILE' 1780environment variable to the script, i. e. to use the cross tools from 1781MontaVista's Hard Hat Linux you can type 1782 1783 CROSS_COMPILE=ppc_8xx- MAKEALL 1784 1785or to build on a native PowerPC system you can type 1786 1787 CROSS_COMPILE=' ' MAKEALL 1788 1789See also "U-Boot Porting Guide" below. 1790 1791 1792 1793Monitor Commands - Overview: 1794============================ 1795 1796go - start application at address 'addr' 1797run - run commands in an environment variable 1798bootm - boot application image from memory 1799bootp - boot image via network using BootP/TFTP protocol 1800tftpboot- boot image via network using TFTP protocol 1801 and env variables "ipaddr" and "serverip" 1802 (and eventually "gatewayip") 1803rarpboot- boot image via network using RARP/TFTP protocol 1804diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1805loads - load S-Record file over serial line 1806loadb - load binary file over serial line (kermit mode) 1807md - memory display 1808mm - memory modify (auto-incrementing) 1809nm - memory modify (constant address) 1810mw - memory write (fill) 1811cp - memory copy 1812cmp - memory compare 1813crc32 - checksum calculation 1814imd - i2c memory display 1815imm - i2c memory modify (auto-incrementing) 1816inm - i2c memory modify (constant address) 1817imw - i2c memory write (fill) 1818icrc32 - i2c checksum calculation 1819iprobe - probe to discover valid I2C chip addresses 1820iloop - infinite loop on address range 1821isdram - print SDRAM configuration information 1822sspi - SPI utility commands 1823base - print or set address offset 1824printenv- print environment variables 1825setenv - set environment variables 1826saveenv - save environment variables to persistent storage 1827protect - enable or disable FLASH write protection 1828erase - erase FLASH memory 1829flinfo - print FLASH memory information 1830bdinfo - print Board Info structure 1831iminfo - print header information for application image 1832coninfo - print console devices and informations 1833ide - IDE sub-system 1834loop - infinite loop on address range 1835mtest - simple RAM test 1836icache - enable or disable instruction cache 1837dcache - enable or disable data cache 1838reset - Perform RESET of the CPU 1839echo - echo args to console 1840version - print monitor version 1841help - print online help 1842? - alias for 'help' 1843 1844 1845Monitor Commands - Detailed Description: 1846======================================== 1847 1848TODO. 1849 1850For now: just type "help <command>". 1851 1852 1853Environment Variables: 1854====================== 1855 1856U-Boot supports user configuration using Environment Variables which 1857can be made persistent by saving to Flash memory. 1858 1859Environment Variables are set using "setenv", printed using 1860"printenv", and saved to Flash using "saveenv". Using "setenv" 1861without a value can be used to delete a variable from the 1862environment. As long as you don't save the environment you are 1863working with an in-memory copy. In case the Flash area containing the 1864environment is erased by accident, a default environment is provided. 1865 1866Some configuration options can be set using Environment Variables: 1867 1868 baudrate - see CONFIG_BAUDRATE 1869 1870 bootdelay - see CONFIG_BOOTDELAY 1871 1872 bootcmd - see CONFIG_BOOTCOMMAND 1873 1874 bootargs - Boot arguments when booting an RTOS image 1875 1876 bootfile - Name of the image to load with TFTP 1877 1878 autoload - if set to "no" (any string beginning with 'n'), 1879 "bootp" will just load perform a lookup of the 1880 configuration from the BOOTP server, but not try to 1881 load any image using TFTP 1882 1883 autostart - if set to "yes", an image loaded using the "bootp", 1884 "rarpboot", "tftpboot" or "diskboot" commands will 1885 be automatically started (by internally calling 1886 "bootm") 1887 1888 initrd_high - restrict positioning of initrd images: 1889 If this variable is not set, initrd images will be 1890 copied to the highest possible address in RAM; this 1891 is usually what you want since it allows for 1892 maximum initrd size. If for some reason you want to 1893 make sure that the initrd image is loaded below the 1894 CFG_BOOTMAPSZ limit, you can set this environment 1895 variable to a value of "no" or "off" or "0". 1896 Alternatively, you can set it to a maximum upper 1897 address to use (U-Boot will still check that it 1898 does not overwrite the U-Boot stack and data). 1899 1900 For instance, when you have a system with 16 MB 1901 RAM, and want to reseve 4 MB from use by Linux, 1902 you can do this by adding "mem=12M" to the value of 1903 the "bootargs" variable. However, now you must make 1904 sure, that the initrd image is placed in the first 1905 12 MB as well - this can be done with 1906 1907 setenv initrd_high 00c00000 1908 1909 ipaddr - IP address; needed for tftpboot command 1910 1911 loadaddr - Default load address for commands like "bootp", 1912 "rarpboot", "tftpboot" or "diskboot" 1913 1914 loads_echo - see CONFIG_LOADS_ECHO 1915 1916 serverip - TFTP server IP address; needed for tftpboot command 1917 1918 bootretry - see CONFIG_BOOT_RETRY_TIME 1919 1920 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1921 1922 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1923 1924 1925The following environment variables may be used and automatically 1926updated by the network boot commands ("bootp" and "rarpboot"), 1927depending the information provided by your boot server: 1928 1929 bootfile - see above 1930 dnsip - IP address of your Domain Name Server 1931 gatewayip - IP address of the Gateway (Router) to use 1932 hostname - Target hostname 1933 ipaddr - see above 1934 netmask - Subnet Mask 1935 rootpath - Pathname of the root filesystem on the NFS server 1936 serverip - see above 1937 1938 1939There are two special Environment Variables: 1940 1941 serial# - contains hardware identification information such 1942 as type string and/or serial number 1943 ethaddr - Ethernet address 1944 1945These variables can be set only once (usually during manufacturing of 1946the board). U-Boot refuses to delete or overwrite these variables 1947once they have been set once. 1948 1949 1950Please note that changes to some configuration parameters may take 1951only effect after the next boot (yes, that's just like Windoze :-). 1952 1953 1954Note for Redundant Ethernet Interfaces: 1955======================================= 1956 1957Some boards come with redundand ethernet interfaces; U-Boot supports 1958such configurations and is capable of automatic selection of a 1959"working" interface when needed. MAC assignemnt works as follows: 1960 1961Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1962MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1963"eth1addr" (=>eth1), "eth2addr", ... 1964 1965If the network interface stores some valid MAC address (for instance 1966in SROM), this is used as default address if there is NO correspon- 1967ding setting in the environment; if the corresponding environment 1968variable is set, this overrides the settings in the card; that means: 1969 1970o If the SROM has a valid MAC address, and there is no address in the 1971 environment, the SROM's address is used. 1972 1973o If there is no valid address in the SROM, and a definition in the 1974 environment exists, then the value from the environment variable is 1975 used. 1976 1977o If both the SROM and the environment contain a MAC address, and 1978 both addresses are the same, this MAC address is used. 1979 1980o If both the SROM and the environment contain a MAC address, and the 1981 addresses differ, the value from the environment is used and a 1982 warning is printed. 1983 1984o If neither SROM nor the environment contain a MAC address, an error 1985 is raised. 1986 1987 1988 1989Image Formats: 1990============== 1991 1992The "boot" commands of this monitor operate on "image" files which 1993can be basicly anything, preceeded by a special header; see the 1994definitions in include/image.h for details; basicly, the header 1995defines the following image properties: 1996 1997* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 1998 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 1999 LynxOS, pSOS, QNX; 2000 Currently supported: Linux, NetBSD, VxWorks, QNX). 2001* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2002 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2003 Currently supported: PowerPC). 2004* Compression Type (Provisions for uncompressed, gzip, bzip2; 2005 Currently supported: uncompressed, gzip). 2006* Load Address 2007* Entry Point 2008* Image Name 2009* Image Timestamp 2010 2011The header is marked by a special Magic Number, and both the header 2012and the data portions of the image are secured against corruption by 2013CRC32 checksums. 2014 2015 2016Linux Support: 2017============== 2018 2019Although U-Boot should support any OS or standalone application 2020easily, Linux has always been in the focus during the design of 2021U-Boot. 2022 2023U-Boot includes many features that so far have been part of some 2024special "boot loader" code within the Linux kernel. Also, any 2025"initrd" images to be used are no longer part of one big Linux image; 2026instead, kernel and "initrd" are separate images. This implementation 2027serves serveral purposes: 2028 2029- the same features can be used for other OS or standalone 2030 applications (for instance: using compressed images to reduce the 2031 Flash memory footprint) 2032 2033- it becomes much easier to port new Linux kernel versions because 2034 lots of low-level, hardware dependend stuff are done by U-Boot 2035 2036- the same Linux kernel image can now be used with different "initrd" 2037 images; of course this also means that different kernel images can 2038 be run with the same "initrd". This makes testing easier (you don't 2039 have to build a new "zImage.initrd" Linux image when you just 2040 change a file in your "initrd"). Also, a field-upgrade of the 2041 software is easier now. 2042 2043 2044Linux HOWTO: 2045============ 2046 2047Porting Linux to U-Boot based systems: 2048--------------------------------------- 2049 2050U-Boot cannot save you from doing all the necessary modifications to 2051configure the Linux device drivers for use with your target hardware 2052(no, we don't intend to provide a full virtual machine interface to 2053Linux :-). 2054 2055But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2056 2057Just make sure your machine specific header file (for instance 2058include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2059Information structure as we define in include/u-boot.h, and make 2060sure that your definition of IMAP_ADDR uses the same value as your 2061U-Boot configuration in CFG_IMMR. 2062 2063 2064Configuring the Linux kernel: 2065----------------------------- 2066 2067No specific requirements for U-Boot. Make sure you have some root 2068device (initial ramdisk, NFS) for your target system. 2069 2070 2071Building a Linux Image: 2072----------------------- 2073 2074With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2075not used. If you use recent kernel source, a new build target 2076"uImage" will exist which automatically builds an image usable by 2077U-Boot. Most older kernels also have support for a "pImage" target, 2078which was introduced for our predecessor project PPCBoot and uses a 2079100% compatible format. 2080 2081Example: 2082 2083 make TQM850L_config 2084 make oldconfig 2085 make dep 2086 make uImage 2087 2088The "uImage" build target uses a special tool (in 'tools/mkimage') to 2089encapsulate a compressed Linux kernel image with header information, 2090CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2091 2092* build a standard "vmlinux" kernel image (in ELF binary format): 2093 2094* convert the kernel into a raw binary image: 2095 2096 ${CROSS_COMPILE}-objcopy -O binary \ 2097 -R .note -R .comment \ 2098 -S vmlinux linux.bin 2099 2100* compress the binary image: 2101 2102 gzip -9 linux.bin 2103 2104* package compressed binary image for U-Boot: 2105 2106 mkimage -A ppc -O linux -T kernel -C gzip \ 2107 -a 0 -e 0 -n "Linux Kernel Image" \ 2108 -d linux.bin.gz uImage 2109 2110 2111The "mkimage" tool can also be used to create ramdisk images for use 2112with U-Boot, either separated from the Linux kernel image, or 2113combined into one file. "mkimage" encapsulates the images with a 64 2114byte header containing information about target architecture, 2115operating system, image type, compression method, entry points, time 2116stamp, CRC32 checksums, etc. 2117 2118"mkimage" can be called in two ways: to verify existing images and 2119print the header information, or to build new images. 2120 2121In the first form (with "-l" option) mkimage lists the information 2122contained in the header of an existing U-Boot image; this includes 2123checksum verification: 2124 2125 tools/mkimage -l image 2126 -l ==> list image header information 2127 2128The second form (with "-d" option) is used to build a U-Boot image 2129from a "data file" which is used as image payload: 2130 2131 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2132 -n name -d data_file image 2133 -A ==> set architecture to 'arch' 2134 -O ==> set operating system to 'os' 2135 -T ==> set image type to 'type' 2136 -C ==> set compression type 'comp' 2137 -a ==> set load address to 'addr' (hex) 2138 -e ==> set entry point to 'ep' (hex) 2139 -n ==> set image name to 'name' 2140 -d ==> use image data from 'datafile' 2141 2142Right now, all Linux kernels use the same load address (0x00000000), 2143but the entry point address depends on the kernel version: 2144 2145- 2.2.x kernels have the entry point at 0x0000000C, 2146- 2.3.x and later kernels have the entry point at 0x00000000. 2147 2148So a typical call to build a U-Boot image would read: 2149 2150 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2151 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2152 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2153 > examples/uImage.TQM850L 2154 Image Name: 2.4.4 kernel for TQM850L 2155 Created: Wed Jul 19 02:34:59 2000 2156 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2157 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2158 Load Address: 0x00000000 2159 Entry Point: 0x00000000 2160 2161To verify the contents of the image (or check for corruption): 2162 2163 -> tools/mkimage -l examples/uImage.TQM850L 2164 Image Name: 2.4.4 kernel for TQM850L 2165 Created: Wed Jul 19 02:34:59 2000 2166 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2167 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2168 Load Address: 0x00000000 2169 Entry Point: 0x00000000 2170 2171NOTE: for embedded systems where boot time is critical you can trade 2172speed for memory and install an UNCOMPRESSED image instead: this 2173needs more space in Flash, but boots much faster since it does not 2174need to be uncompressed: 2175 2176 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2177 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2178 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2179 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2180 > examples/uImage.TQM850L-uncompressed 2181 Image Name: 2.4.4 kernel for TQM850L 2182 Created: Wed Jul 19 02:34:59 2000 2183 Image Type: PowerPC Linux Kernel Image (uncompressed) 2184 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2185 Load Address: 0x00000000 2186 Entry Point: 0x00000000 2187 2188 2189Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2190when your kernel is intended to use an initial ramdisk: 2191 2192 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2193 > -A ppc -O linux -T ramdisk -C gzip \ 2194 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2195 Image Name: Simple Ramdisk Image 2196 Created: Wed Jan 12 14:01:50 2000 2197 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2198 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2199 Load Address: 0x00000000 2200 Entry Point: 0x00000000 2201 2202 2203Installing a Linux Image: 2204------------------------- 2205 2206To downloading a U-Boot image over the serial (console) interface, 2207you must convert the image to S-Record format: 2208 2209 objcopy -I binary -O srec examples/image examples/image.srec 2210 2211The 'objcopy' does not understand the information in the U-Boot 2212image header, so the resulting S-Record file will be relative to 2213address 0x00000000. To load it to a given address, you need to 2214specify the target address as 'offset' parameter with the 'loads' 2215command. 2216 2217Example: install the image to address 0x40100000 (which on the 2218TQM8xxL is in the first Flash bank): 2219 2220 => erase 40100000 401FFFFF 2221 2222 .......... done 2223 Erased 8 sectors 2224 2225 => loads 40100000 2226 ## Ready for S-Record download ... 2227 ~>examples/image.srec 2228 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2229 ... 2230 15989 15990 15991 15992 2231 [file transfer complete] 2232 [connected] 2233 ## Start Addr = 0x00000000 2234 2235 2236You can check the success of the download using the 'iminfo' command; 2237this includes a checksum verification so you can be sure no data 2238corruption happened: 2239 2240 => imi 40100000 2241 2242 ## Checking Image at 40100000 ... 2243 Image Name: 2.2.13 for initrd on TQM850L 2244 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2245 Data Size: 335725 Bytes = 327 kB = 0 MB 2246 Load Address: 00000000 2247 Entry Point: 0000000c 2248 Verifying Checksum ... OK 2249 2250 2251 2252Boot Linux: 2253----------- 2254 2255The "bootm" command is used to boot an application that is stored in 2256memory (RAM or Flash). In case of a Linux kernel image, the contents 2257of the "bootargs" environment variable is passed to the kernel as 2258parameters. You can check and modify this variable using the 2259"printenv" and "setenv" commands: 2260 2261 2262 => printenv bootargs 2263 bootargs=root=/dev/ram 2264 2265 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2266 2267 => printenv bootargs 2268 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2269 2270 => bootm 40020000 2271 ## Booting Linux kernel at 40020000 ... 2272 Image Name: 2.2.13 for NFS on TQM850L 2273 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2274 Data Size: 381681 Bytes = 372 kB = 0 MB 2275 Load Address: 00000000 2276 Entry Point: 0000000c 2277 Verifying Checksum ... OK 2278 Uncompressing Kernel Image ... OK 2279 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 2280 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2281 time_init: decrementer frequency = 187500000/60 2282 Calibrating delay loop... 49.77 BogoMIPS 2283 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2284 ... 2285 2286If you want to boot a Linux kernel with initial ram disk, you pass 2287the memory addreses of both the kernel and the initrd image (PPBCOOT 2288format!) to the "bootm" command: 2289 2290 => imi 40100000 40200000 2291 2292 ## Checking Image at 40100000 ... 2293 Image Name: 2.2.13 for initrd on TQM850L 2294 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2295 Data Size: 335725 Bytes = 327 kB = 0 MB 2296 Load Address: 00000000 2297 Entry Point: 0000000c 2298 Verifying Checksum ... OK 2299 2300 ## Checking Image at 40200000 ... 2301 Image Name: Simple Ramdisk Image 2302 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2303 Data Size: 566530 Bytes = 553 kB = 0 MB 2304 Load Address: 00000000 2305 Entry Point: 00000000 2306 Verifying Checksum ... OK 2307 2308 => bootm 40100000 40200000 2309 ## Booting Linux kernel at 40100000 ... 2310 Image Name: 2.2.13 for initrd on TQM850L 2311 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2312 Data Size: 335725 Bytes = 327 kB = 0 MB 2313 Load Address: 00000000 2314 Entry Point: 0000000c 2315 Verifying Checksum ... OK 2316 Uncompressing Kernel Image ... OK 2317 ## Loading RAMDisk Image at 40200000 ... 2318 Image Name: Simple Ramdisk Image 2319 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2320 Data Size: 566530 Bytes = 553 kB = 0 MB 2321 Load Address: 00000000 2322 Entry Point: 00000000 2323 Verifying Checksum ... OK 2324 Loading Ramdisk ... OK 2325 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 2326 Boot arguments: root=/dev/ram 2327 time_init: decrementer frequency = 187500000/60 2328 Calibrating delay loop... 49.77 BogoMIPS 2329 ... 2330 RAMDISK: Compressed image found at block 0 2331 VFS: Mounted root (ext2 filesystem). 2332 2333 bash# 2334 2335 2336Standalone HOWTO: 2337================= 2338 2339One of the features of U-Boot is that you can dynamically load and 2340run "standalone" applications, which can use some resources of 2341U-Boot like console I/O functions or interrupt services. 2342 2343Two simple examples are included with the sources: 2344 2345"Hello World" Demo: 2346------------------- 2347 2348'examples/hello_world.c' contains a small "Hello World" Demo 2349application; it is automatically compiled when you build U-Boot. 2350It's configured to run at address 0x00040004, so you can play with it 2351like that: 2352 2353 => loads 2354 ## Ready for S-Record download ... 2355 ~>examples/hello_world.srec 2356 1 2 3 4 5 6 7 8 9 10 11 ... 2357 [file transfer complete] 2358 [connected] 2359 ## Start Addr = 0x00040004 2360 2361 => go 40004 Hello World! This is a test. 2362 ## Starting application at 0x00040004 ... 2363 Hello World 2364 argc = 7 2365 argv[0] = "40004" 2366 argv[1] = "Hello" 2367 argv[2] = "World!" 2368 argv[3] = "This" 2369 argv[4] = "is" 2370 argv[5] = "a" 2371 argv[6] = "test." 2372 argv[7] = "<NULL>" 2373 Hit any key to exit ... 2374 2375 ## Application terminated, rc = 0x0 2376 2377Another example, which demonstrates how to register a CPM interrupt 2378handler with the U-Boot code, can be found in 'examples/timer.c'. 2379Here, a CPM timer is set up to generate an interrupt every second. 2380The interrupt service routine is trivial, just printing a '.' 2381character, but this is just a demo program. The application can be 2382controlled by the following keys: 2383 2384 ? - print current values og the CPM Timer registers 2385 b - enable interrupts and start timer 2386 e - stop timer and disable interrupts 2387 q - quit application 2388 2389 => loads 2390 ## Ready for S-Record download ... 2391 ~>examples/timer.srec 2392 1 2 3 4 5 6 7 8 9 10 11 ... 2393 [file transfer complete] 2394 [connected] 2395 ## Start Addr = 0x00040004 2396 2397 => go 40004 2398 ## Starting application at 0x00040004 ... 2399 TIMERS=0xfff00980 2400 Using timer 1 2401 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2402 2403Hit 'b': 2404 [q, b, e, ?] Set interval 1000000 us 2405 Enabling timer 2406Hit '?': 2407 [q, b, e, ?] ........ 2408 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2409Hit '?': 2410 [q, b, e, ?] . 2411 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2412Hit '?': 2413 [q, b, e, ?] . 2414 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2415Hit '?': 2416 [q, b, e, ?] . 2417 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2418Hit 'e': 2419 [q, b, e, ?] ...Stopping timer 2420Hit 'q': 2421 [q, b, e, ?] ## Application terminated, rc = 0x0 2422 2423 2424NetBSD Notes: 2425============= 2426 2427Starting at version 0.9.2, U-Boot supports NetBSD both as host 2428(build U-Boot) and target system (boots NetBSD/mpc8xx). 2429 2430Building requires a cross environment; it is known to work on 2431NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2432need gmake since the Makefiles are not compatible with BSD make). 2433Note that the cross-powerpc package does not install include files; 2434attempting to build U-Boot will fail because <machine/ansi.h> is 2435missing. This file has to be installed and patched manually: 2436 2437 # cd /usr/pkg/cross/powerpc-netbsd/include 2438 # mkdir powerpc 2439 # ln -s powerpc machine 2440 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2441 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2442 2443Native builds *don't* work due to incompatibilities between native 2444and U-Boot include files. 2445 2446Booting assumes that (the first part of) the image booted is a 2447stage-2 loader which in turn loads and then invokes the kernel 2448proper. Loader sources will eventually appear in the NetBSD source 2449tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2450meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2451details. 2452 2453 2454Implementation Internals: 2455========================= 2456 2457The following is not intended to be a complete description of every 2458implementation detail. However, it should help to understand the 2459inner workings of U-Boot and make it easier to port it to custom 2460hardware. 2461 2462 2463Initial Stack, Global Data: 2464--------------------------- 2465 2466The implementation of U-Boot is complicated by the fact that U-Boot 2467starts running out of ROM (flash memory), usually without access to 2468system RAM (because the memory controller is not initialized yet). 2469This means that we don't have writable Data or BSS segments, and BSS 2470is not initialized as zero. To be able to get a C environment working 2471at all, we have to allocate at least a minimal stack. Implementation 2472options for this are defined and restricted by the CPU used: Some CPU 2473models provide on-chip memory (like the IMMR area on MPC8xx and 2474MPC826x processors), on others (parts of) the data cache can be 2475locked as (mis-) used as memory, etc. 2476 2477It is essential to remember this, since it has some impact on the C 2478code for the initialization procedures: 2479 2480* Initialized global data (data segment) is read-only. Do not attempt 2481 to write it. 2482 2483* Do not use any unitialized global data (or implicitely initialized 2484 as zero data - BSS segment) at all - this is undefined, initiali- 2485 zation is performed later (when relocationg to RAM). 2486 2487* Stack space is very limited. Avoid big data buffers or things like 2488 that. 2489 2490Having only the stack as writable memory limits means we cannot use 2491normal global data to share information beween the code. But it 2492turned out that the implementation of U-Boot can be greatly 2493simplified by making a global data structure (gd_t) available to all 2494functions. We could pass a pointer to this data as argument to _all_ 2495functions, but this would bloat the code. Instead we use a feature of 2496the GCC compiler (Global Register Variables) to share the data: we 2497place a pointer (gd) to the global data into a register which we 2498reserve for this purpose. 2499 2500When chosing a register for such a purpose we are restricted by the 2501relevant (E)ABI specifications for the current architecture, and by 2502GCC's implementation. 2503 2504For PowerPC, the following registers have specific use: 2505 R1: stack pointer 2506 R2: TOC pointer 2507 R3-R4: parameter passing and return values 2508 R5-R10: parameter passing 2509 R13: small data area pointer 2510 R30: GOT pointer 2511 R31: frame pointer 2512 2513 (U-Boot also uses R14 as internal GOT pointer.) 2514 2515 ==> U-Boot will use R29 to hold a pointer to the global data 2516 2517 Note: on PPC, we could use a static initializer (since the 2518 address of the global data structure is known at compile time), 2519 but it turned out that reserving a register results in somewhat 2520 smaller code - although the code savings are not that big (on 2521 average for all boards 752 bytes for the whole U-Boot image, 2522 624 text + 127 data). 2523 2524On ARM, the following registers are used: 2525 2526 R0: function argument word/integer result 2527 R1-R3: function argument word 2528 R9: GOT pointer 2529 R10: stack limit (used only if stack checking if enabled) 2530 R11: argument (frame) pointer 2531 R12: temporary workspace 2532 R13: stack pointer 2533 R14: link register 2534 R15: program counter 2535 2536 ==> U-Boot will use R8 to hold a pointer to the global data 2537 2538 2539 2540Memory Management: 2541------------------ 2542 2543U-Boot runs in system state and uses physical addresses, i.e. the 2544MMU is not used either for address mapping nor for memory protection. 2545 2546The available memory is mapped to fixed addresses using the memory 2547controller. In this process, a contiguous block is formed for each 2548memory type (Flash, SDRAM, SRAM), even when it consists of several 2549physical memory banks. 2550 2551U-Boot is installed in the first 128 kB of the first Flash bank (on 2552TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2553booting and sizing and initializing DRAM, the code relocates itself 2554to the upper end of DRAM. Immediately below the U-Boot code some 2555memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2556configuration setting]. Below that, a structure with global Board 2557Info data is placed, followed by the stack (growing downward). 2558 2559Additionally, some exception handler code is copied to the low 8 kB 2560of DRAM (0x00000000 ... 0x00001FFF). 2561 2562So a typical memory configuration with 16 MB of DRAM could look like 2563this: 2564 2565 0x0000 0000 Exception Vector code 2566 : 2567 0x0000 1FFF 2568 0x0000 2000 Free for Application Use 2569 : 2570 : 2571 2572 : 2573 : 2574 0x00FB FF20 Monitor Stack (Growing downward) 2575 0x00FB FFAC Board Info Data and permanent copy of global data 2576 0x00FC 0000 Malloc Arena 2577 : 2578 0x00FD FFFF 2579 0x00FE 0000 RAM Copy of Monitor Code 2580 ... eventually: LCD or video framebuffer 2581 ... eventually: pRAM (Protected RAM - unchanged by reset) 2582 0x00FF FFFF [End of RAM] 2583 2584 2585System Initialization: 2586---------------------- 2587 2588In the reset configuration, U-Boot starts at the reset entry point 2589(on most PowerPC systens at address 0x00000100). Because of the reset 2590configuration for CS0# this is a mirror of the onboard Flash memory. 2591To be able to re-map memory U-Boot then jumps to it's link address. 2592To be able to implement the initialization code in C, a (small!) 2593initial stack is set up in the internal Dual Ported RAM (in case CPUs 2594which provide such a feature like MPC8xx or MPC8260), or in a locked 2595part of the data cache. After that, U-Boot initializes the CPU core, 2596the caches and the SIU. 2597 2598Next, all (potentially) available memory banks are mapped using a 2599preliminary mapping. For example, we put them on 512 MB boundaries 2600(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2601on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2602programmed for SDRAM access. Using the temporary configuration, a 2603simple memory test is run that determines the size of the SDRAM 2604banks. 2605 2606When there is more than one SDRAM bank, and the banks are of 2607different size, the larger is mapped first. For equal size, the first 2608bank (CS2#) is mapped first. The first mapping is always for address 26090x00000000, with any additional banks following immediately to create 2610contiguous memory starting from 0. 2611 2612Then, the monitor installs itself at the upper end of the SDRAM area 2613and allocates memory for use by malloc() and for the global Board 2614Info data; also, the exception vector code is copied to the low RAM 2615pages, and the final stack is set up. 2616 2617Only after this relocation will you have a "normal" C environment; 2618until that you are restricted in several ways, mostly because you are 2619running from ROM, and because the code will have to be relocated to a 2620new address in RAM. 2621 2622 2623U-Boot Porting Guide: 2624---------------------- 2625 2626[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2627list, Octover 2002] 2628 2629 2630int main (int argc, char *argv[]) 2631{ 2632 sighandler_t no_more_time; 2633 2634 signal (SIGALRM, no_more_time); 2635 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2636 2637 if (available_money > available_manpower) { 2638 pay consultant to port U-Boot; 2639 return 0; 2640 } 2641 2642 Download latest U-Boot source; 2643 2644 if (clueless) { 2645 email ("Hi, I am new to U-Boot, how do I get started?"); 2646 } 2647 2648 while (learning) { 2649 Read the README file in the top level directory; 2650 Read http://www.denx.de/re/DPLG.html 2651 Read the source, Luke; 2652 } 2653 2654 if (available_money > toLocalCurrency ($2500)) { 2655 Buy a BDI2000; 2656 } else { 2657 Add a lot of aggravation and time; 2658 } 2659 2660 Create your own board support subdirectory; 2661 2662 while (!running) { 2663 do { 2664 Add / modify source code; 2665 } until (compiles); 2666 Debug; 2667 if (clueless) 2668 email ("Hi, I am having problems..."); 2669 } 2670 Send patch file to Wolfgang; 2671 2672 return 0; 2673} 2674 2675void no_more_time (int sig) 2676{ 2677 hire_a_guru(); 2678} 2679 2680 2681 2682Coding Standards: 2683----------------- 2684 2685All contributions to U-Boot should conform to the Linux kernel 2686coding style; see the file "Documentation/CodingStyle" in your Linux 2687kernel source directory. 2688 2689Please note that U-Boot is implemented in C (and to some small parts 2690in Assembler); no C++ is used, so please do not use C++ style 2691comments (//) in your code. 2692 2693Submissions which do not conform to the standards may be returned 2694with a request to reformat the changes. 2695 2696 2697Submitting Patches: 2698------------------- 2699 2700Since the number of patches for U-Boot is growing, we need to 2701establish some rules. Submissions which do not conform to these rules 2702may be rejected, even when they contain important and valuable stuff. 2703 2704 2705When you send a patch, please include the following information with 2706it: 2707 2708* For bug fixes: a description of the bug and how your patch fixes 2709 this bug. Please try to include a way of demonstrating that the 2710 patch actually fixes something. 2711 2712* For new features: a description of the feature and your 2713 implementation. 2714 2715* A CHANGELOG entry as plaintext (separate from the patch) 2716 2717* For major contributions, your entry to the CREDITS file 2718 2719* When you add support for a new board, don't forget to add this 2720 board to the MAKEALL script, too. 2721 2722* If your patch adds new configuration options, don't forget to 2723 document these in the README file. 2724 2725* The patch itself. If you are accessing the CVS repository use "cvs 2726 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2727 version of diff does not support these options, then get the latest 2728 version of GNU diff. 2729 2730 We accept patches as plain text, MIME attachments or as uuencoded 2731 gzipped text. 2732 2733Notes: 2734 2735* Before sending the patch, run the MAKEALL script on your patched 2736 source tree and make sure that no errors or warnings are reported 2737 for any of the boards. 2738 2739* Keep your modifications to the necessary minimum: A patch 2740 containing several unrelated changes or arbitrary reformats will be 2741 returned with a request to re-formatting / split it. 2742 2743* If you modify existing code, make sure that your new code does not 2744 add to the memory footprint of the code ;-) Small is beautiful! 2745 When adding new features, these should compile conditionally only 2746 (using #ifdef), and the resulting code with the new feature 2747 disabled must not need more memory than the old code without your 2748 modification. 2749