1# 2# (C) Copyright 2000 - 2002 3# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4# 5# See file CREDITS for list of people who contributed to this 6# project. 7# 8# This program is free software; you can redistribute it and/or 9# modify it under the terms of the GNU General Public License as 10# published by the Free Software Foundation; either version 2 of 11# the License, or (at your option) any later version. 12# 13# This program is distributed in the hope that it will be useful, 14# but WITHOUT ANY WARRANTY; without even the implied warranty of 15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16# GNU General Public License for more details. 17# 18# You should have received a copy of the GNU General Public License 19# along with this program; if not, write to the Free Software 20# Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21# MA 02111-1307 USA 22# 23 24Summary: 25======== 26 27This directory contains the source code for U-Boot, a boot loader for 28Embedded boards based on PowerPC and ARM processors, which can be 29installed in a boot ROM and used to initialize and test the hardware 30or to download and run application code. 31 32The development of U-Boot is closely related to Linux: some parts of 33the source code originate in the Linux source tree, we have some 34header files in common, and special provision has been made to 35support booting of Linux images. 36 37Some attention has been paid to make this software easily 38configurable and extendable. For instance, all monitor commands are 39implemented with the same call interface, so that it's very easy to 40add new commands. Also, instead of permanently adding rarely used 41code (for instance hardware test utilities) to the monitor, you can 42load and run it dynamically. 43 44 45Status: 46======= 47 48In general, all boards for which a configuration option exists in the 49Makefile have been tested to some extent and can be considered 50"working". In fact, many of them are used in production systems. 51 52In case of problems see the CHANGELOG and CREDITS files to find out 53who contributed the specific port. 54 55 56Where to get help: 57================== 58 59In case you have questions about, problems with or contributions for 60U-Boot you should send a message to the U-Boot mailing list at 61<u-boot-users@lists.sourceforge.net>. There is also an archive of 62previous traffic on the mailing list - please search the archive 63before asking FAQ's. Please see 64http://lists.sourceforge.net/lists/listinfo/u-boot-users/ 65 66 67Where we come from: 68=================== 69 70- start from 8xxrom sources 71- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 72- clean up code 73- make it easier to add custom boards 74- make it possible to add other [PowerPC] CPUs 75- extend functions, especially: 76 * Provide extended interface to Linux boot loader 77 * S-Record download 78 * network boot 79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot 80- create ARMBoot project (http://sourceforge.net/projects/armboot) 81- add other CPU families (starting with ARM) 82- create U-Boot project (http://sourceforge.net/projects/u-boot) 83 84 85Names and Spelling: 86=================== 87 88The "official" name of this project is "Das U-Boot". The spelling 89"U-Boot" shall be used in all written text (documentation, comments 90in source files etc.). Example: 91 92 This is the README file for the U-Boot project. 93 94File names etc. shall be based on the string "u-boot". Examples: 95 96 include/asm-ppc/u-boot.h 97 98 #include <asm/u-boot.h> 99 100Variable names, preprocessor constants etc. shall be either based on 101the string "u_boot" or on "U_BOOT". Example: 102 103 U_BOOT_VERSION u_boot_logo 104 IH_OS_U_BOOT u_boot_hush_start 105 106 107Versioning: 108=========== 109 110U-Boot uses a 3 level version number containing a version, a 111sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2", 112sub-version "34", and patchlevel "4". 113 114The patchlevel is used to indicate certain stages of development 115between released versions, i. e. officially released versions of 116U-Boot will always have a patchlevel of "0". 117 118 119Directory Hierarchy: 120==================== 121 122- board Board dependend files 123- common Misc architecture independend functions 124- cpu CPU specific files 125- disk Code for disk drive partition handling 126- doc Documentation (don't expect too much) 127- drivers Common used device drivers 128- dtt Digital Thermometer and Thermostat drivers 129- examples Example code for standalone applications, etc. 130- include Header Files 131- disk Harddisk interface code 132- net Networking code 133- ppc Files generic to PowerPC architecture 134- post Power On Self Test 135- post/arch Symlink to architecture specific Power On Self Test 136- post/arch-ppc PowerPC architecture specific Power On Self Test 137- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test 138- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test 139- rtc Real Time Clock drivers 140- tools Tools to build S-Record or U-Boot images, etc. 141 142- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 143- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs 144- cpu/mpc824x Files specific to Motorola MPC824x CPUs 145- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 146- cpu/ppc4xx Files specific to IBM 4xx CPUs 147 148- board/RPXClassic 149 Files specific to RPXClassic boards 150- board/RPXlite Files specific to RPXlite boards 151- board/c2mon Files specific to c2mon boards 152- board/cogent Files specific to Cogent boards 153 (need further configuration) 154 Files specific to CPCIISER4 boards 155- board/cpu86 Files specific to CPU86 boards 156- board/cray/ Files specific to boards manufactured by Cray 157- board/cray/L1 Files specific to L1 boards 158- board/cu824 Files specific to CU824 boards 159- board/ebony Files specific to IBM Ebony board 160- board/eric Files specific to ERIC boards 161- board/esd/ Files specific to boards manufactured by ESD 162- board/esd/adciop Files specific to ADCIOP boards 163- board/esd/ar405 Files specific to AR405 boards 164- board/esd/canbt Files specific to CANBT boards 165- board/esd/cpci405 Files specific to CPCI405 boards 166- board/esd/cpciiser4 Files specific to CPCIISER4 boards 167- board/esd/common Common files for ESD boards 168- board/esd/dasa_sim Files specific to DASA_SIM boards 169- board/esd/du405 Files specific to DU405 boards 170- board/esd/ocrtc Files specific to OCRTC boards 171- board/esd/pci405 Files specific to PCI405 boards 172- board/esteem192e 173 Files specific to ESTEEM192E boards 174- board/etx094 Files specific to ETX_094 boards 175- board/evb64260 176 Files specific to EVB64260 boards 177- board/fads Files specific to FADS boards 178- board/flagadm Files specific to FLAGADM boards 179- board/gen860t Files specific to GEN860T boards 180- board/genietv Files specific to GENIETV boards 181- board/gth Files specific to GTH boards 182- board/hermes Files specific to HERMES boards 183- board/hymod Files specific to HYMOD boards 184- board/icu862 Files specific to ICU862 boards 185- board/ip860 Files specific to IP860 boards 186- board/iphase4539 187 Files specific to Interphase4539 boards 188- board/ivm Files specific to IVMS8/IVML24 boards 189- board/lantec Files specific to LANTEC boards 190- board/lwmon Files specific to LWMON boards 191- board/mbx8xx Files specific to MBX boards 192- board/mpc8260ads 193 Files specific to MMPC8260ADS boards 194- board/mpl/ Files specific to boards manufactured by MPL 195- board/mpl/common Common files for MPL boards 196- board/mpl/pip405 Files specific to PIP405 boards 197- board/mpl/mip405 Files specific to MIP405 boards 198- board/musenki Files specific to MUSEKNI boards 199- board/mvs1 Files specific to MVS1 boards 200- board/nx823 Files specific to NX823 boards 201- board/oxc Files specific to OXC boards 202- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 203- board/pm826 Files specific to PM826 boards 204- board/ppmc8260 205 Files specific to PPMC8260 boards 206- board/rpxsuper 207 Files specific to RPXsuper boards 208- board/rsdproto 209 Files specific to RSDproto boards 210- board/sandpoint 211 Files specific to Sandpoint boards 212- board/sbc8260 Files specific to SBC8260 boards 213- board/sacsng Files specific to SACSng boards 214- board/siemens Files specific to boards manufactured by Siemens AG 215- board/siemens/CCM Files specific to CCM boards 216- board/siemens/IAD210 Files specific to IAD210 boards 217- board/siemens/SCM Files specific to SCM boards 218- board/siemens/pcu_e Files specific to PCU_E boards 219- board/sixnet Files specific to SIXNET boards 220- board/spd8xx Files specific to SPD8xxTS boards 221- board/tqm8260 Files specific to TQM8260 boards 222- board/tqm8xx Files specific to TQM8xxL boards 223- board/w7o Files specific to W7O boards 224- board/walnut405 225 Files specific to Walnut405 boards 226- board/westel/ Files specific to boards manufactured by Westel Wireless 227- board/westel/amx860 Files specific to AMX860 boards 228- board/utx8245 Files specific to UTX8245 boards 229 230Software Configuration: 231======================= 232 233Configuration is usually done using C preprocessor defines; the 234rationale behind that is to avoid dead code whenever possible. 235 236There are two classes of configuration variables: 237 238* Configuration _OPTIONS_: 239 These are selectable by the user and have names beginning with 240 "CONFIG_". 241 242* Configuration _SETTINGS_: 243 These depend on the hardware etc. and should not be meddled with if 244 you don't know what you're doing; they have names beginning with 245 "CFG_". 246 247Later we will add a configuration tool - probably similar to or even 248identical to what's used for the Linux kernel. Right now, we have to 249do the configuration by hand, which means creating some symbolic 250links and editing some configuration files. We use the TQM8xxL boards 251as an example here. 252 253 254Selection of Processor Architecture and Board Type: 255--------------------------------------------------- 256 257For all supported boards there are ready-to-use default 258configurations available; just type "make <board_name>_config". 259 260Example: For a TQM823L module type: 261 262 cd u-boot 263 make TQM823L_config 264 265For the Cogent platform, you need to specify the cpu type as well; 266e.g. "make cogent_mpc8xx_config". And also configure the cogent 267directory according to the instructions in cogent/README. 268 269 270Configuration Options: 271---------------------- 272 273Configuration depends on the combination of board and CPU type; all 274such information is kept in a configuration file 275"include/configs/<board_name>.h". 276 277Example: For a TQM823L module, all configuration settings are in 278"include/configs/TQM823L.h". 279 280 281Many of the options are named exactly as the corresponding Linux 282kernel configuration options. The intention is to make it easier to 283build a config tool - later. 284 285 286The following options need to be configured: 287 288- CPU Type: Define exactly one of 289 290 PowerPC based CPUs: 291 ------------------- 292 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 293 or CONFIG_MPC824X, CONFIG_MPC8260 294 or CONFIG_IOP480 295 or CONFIG_405GP 296 or CONFIG_440 297 or CONFIG_MPC74xx 298 299 ARM based CPUs: 300 --------------- 301 CONFIG_SA1110 302 CONFIG_ARM7 303 CONFIG_PXA250 304 305 306- Board Type: Define exactly one of 307 308 PowerPC based boards: 309 --------------------- 310 311 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 312 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 313 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 314 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 315 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 316 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 317 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 318 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 319 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 320 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 321 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 322 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 323 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 324 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 325 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 326 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 327 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 328 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 329 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 330 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 331 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 332 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 333 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 334 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 335 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 336 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 337 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 338 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 339 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 340 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L, 341 CONFIG_V37 342 343 ARM based boards: 344 ----------------- 345 346 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 347 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 348 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 349 CONFIG_TRAB 350 351 352- CPU Module Type: (if CONFIG_COGENT is defined) 353 Define exactly one of 354 CONFIG_CMA286_60_OLD 355--- FIXME --- not tested yet: 356 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 357 CONFIG_CMA287_23, CONFIG_CMA287_50 358 359- Motherboard Type: (if CONFIG_COGENT is defined) 360 Define exactly one of 361 CONFIG_CMA101, CONFIG_CMA102 362 363- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 364 Define one or more of 365 CONFIG_CMA302 366 367- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 368 Define one or more of 369 CONFIG_LCD_HEARTBEAT - update a character position on 370 the lcd display every second with 371 a "rotator" |\-/|\-/ 372 373- MPC824X Family Member (if CONFIG_MPC824X is defined) 374 Define exactly one of 375 CONFIG_MPC8240, CONFIG_MPC8245 376 377- 8xx CPU Options: (if using an 8xx cpu) 378 Define one or more of 379 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 380 no 32KHz reference PIT/RTC clock 381 382- Clock Interface: 383 CONFIG_CLOCKS_IN_MHZ 384 385 U-Boot stores all clock information in Hz 386 internally. For binary compatibility with older Linux 387 kernels (which expect the clocks passed in the 388 bd_info data to be in MHz) the environment variable 389 "clocks_in_mhz" can be defined so that U-Boot 390 converts clock data to MHZ before passing it to the 391 Linux kernel. 392 393 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 394 "clocks_in_mhz=1" is automatically included in the 395 default environment. 396 397- Console Interface: 398 Depending on board, define exactly one serial port 399 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 400 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 401 console by defining CONFIG_8xx_CONS_NONE 402 403 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 404 port routines must be defined elsewhere 405 (i.e. serial_init(), serial_getc(), ...) 406 407 CONFIG_CFB_CONSOLE 408 Enables console device for a color framebuffer. Needs following 409 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 410 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 411 (default big endian) 412 VIDEO_HW_RECTFILL graphic chip supports 413 rectangle fill 414 (cf. smiLynxEM) 415 VIDEO_HW_BITBLT graphic chip supports 416 bit-blit (cf. smiLynxEM) 417 VIDEO_VISIBLE_COLS visible pixel columns 418 (cols=pitch) 419 VIDEO_VISIBLE_ROWS visible pixel rows 420 VIDEO_PIXEL_SIZE bytes per pixel 421 VIDEO_DATA_FORMAT graphic data format 422 (0-5, cf. cfb_console.c) 423 VIDEO_FB_ADRS framebuffer address 424 VIDEO_KBD_INIT_FCT keyboard int fct 425 (i.e. i8042_kbd_init()) 426 VIDEO_TSTC_FCT test char fct 427 (i.e. i8042_tstc) 428 VIDEO_GETC_FCT get char fct 429 (i.e. i8042_getc) 430 CONFIG_CONSOLE_CURSOR cursor drawing on/off 431 (requires blink timer 432 cf. i8042.c) 433 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 434 CONFIG_CONSOLE_TIME display time/date info in 435 upper right corner 436 (requires CFG_CMD_DATE) 437 CONFIG_VIDEO_LOGO display Linux logo in 438 upper left corner 439 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 440 linux_logo.h for logo. 441 Requires CONFIG_VIDEO_LOGO 442 CONFIG_CONSOLE_EXTRA_INFO 443 addional board info beside 444 the logo 445 446 When CONFIG_CFB_CONSOLE is defined, video console is 447 default i/o. Serial console can be forced with 448 environment 'console=serial'. 449 450- Console Baudrate: 451 CONFIG_BAUDRATE - in bps 452 Select one of the baudrates listed in 453 CFG_BAUDRATE_TABLE, see below. 454 455- Interrupt driven serial port input: 456 CONFIG_SERIAL_SOFTWARE_FIFO 457 458 PPC405GP only. 459 Use an interrupt handler for receiving data on the 460 serial port. It also enables using hardware handshake 461 (RTS/CTS) and UART's built-in FIFO. Set the number of 462 bytes the interrupt driven input buffer should have. 463 464 Set to 0 to disable this feature (this is the default). 465 This will also disable hardware handshake. 466 467- Boot Delay: CONFIG_BOOTDELAY - in seconds 468 Delay before automatically booting the default image; 469 set to -1 to disable autoboot. 470 471 See doc/README.autoboot for these options that 472 work with CONFIG_BOOTDELAY. None are required. 473 CONFIG_BOOT_RETRY_TIME 474 CONFIG_BOOT_RETRY_MIN 475 CONFIG_AUTOBOOT_KEYED 476 CONFIG_AUTOBOOT_PROMPT 477 CONFIG_AUTOBOOT_DELAY_STR 478 CONFIG_AUTOBOOT_STOP_STR 479 CONFIG_AUTOBOOT_DELAY_STR2 480 CONFIG_AUTOBOOT_STOP_STR2 481 CONFIG_ZERO_BOOTDELAY_CHECK 482 CONFIG_RESET_TO_RETRY 483 484- Autoboot Command: 485 CONFIG_BOOTCOMMAND 486 Only needed when CONFIG_BOOTDELAY is enabled; 487 define a command string that is automatically executed 488 when no character is read on the console interface 489 within "Boot Delay" after reset. 490 491 CONFIG_BOOTARGS 492 This can be used to pass arguments to the bootm 493 command. The value of CONFIG_BOOTARGS goes into the 494 environment value "bootargs". 495 496 CONFIG_RAMBOOT and CONFIG_NFSBOOT 497 The value of these goes into the environment as 498 "ramboot" and "nfsboot" respectively, and can be used 499 as a convenience, when switching between booting from 500 ram and nfs. 501 502- Pre-Boot Commands: 503 CONFIG_PREBOOT 504 505 When this option is #defined, the existence of the 506 environment variable "preboot" will be checked 507 immediately before starting the CONFIG_BOOTDELAY 508 countdown and/or running the auto-boot command resp. 509 entering interactive mode. 510 511 This feature is especially useful when "preboot" is 512 automatically generated or modified. For an example 513 see the LWMON board specific code: here "preboot" is 514 modified when the user holds down a certain 515 combination of keys on the (special) keyboard when 516 booting the systems 517 518- Serial Download Echo Mode: 519 CONFIG_LOADS_ECHO 520 If defined to 1, all characters received during a 521 serial download (using the "loads" command) are 522 echoed back. This might be needed by some terminal 523 emulations (like "cu"), but may as well just take 524 time on others. This setting #define's the initial 525 value of the "loads_echo" environment variable. 526 527- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 528 CONFIG_KGDB_BAUDRATE 529 Select one of the baudrates listed in 530 CFG_BAUDRATE_TABLE, see below. 531 532- Monitor Functions: 533 CONFIG_COMMANDS 534 Most monitor functions can be selected (or 535 de-selected) by adjusting the definition of 536 CONFIG_COMMANDS; to select individual functions, 537 #define CONFIG_COMMANDS by "OR"ing any of the 538 following values: 539 540 #define enables commands: 541 ------------------------- 542 CFG_CMD_ASKENV * ask for env variable 543 CFG_CMD_BDI bdinfo 544 CFG_CMD_BEDBUG Include BedBug Debugger 545 CFG_CMD_BOOTD bootd 546 CFG_CMD_CACHE icache, dcache 547 CFG_CMD_CONSOLE coninfo 548 CFG_CMD_DATE * support for RTC, date/time... 549 CFG_CMD_DHCP DHCP support 550 CFG_CMD_ECHO * echo arguments 551 CFG_CMD_EEPROM * EEPROM read/write support 552 CFG_CMD_ELF bootelf, bootvx 553 CFG_CMD_ENV saveenv 554 CFG_CMD_FDC * Floppy Disk Support 555 CFG_CMD_FDOS * Dos diskette Support 556 CFG_CMD_FLASH flinfo, erase, protect 557 CFG_CMD_FPGA FPGA device initialization support 558 CFG_CMD_I2C * I2C serial bus support 559 CFG_CMD_IDE * IDE harddisk support 560 CFG_CMD_IMI iminfo 561 CFG_CMD_IMMAP * IMMR dump support 562 CFG_CMD_IRQ * irqinfo 563 CFG_CMD_KGDB * kgdb 564 CFG_CMD_LOADB loadb 565 CFG_CMD_LOADS loads 566 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 567 loop, mtest 568 CFG_CMD_MII MII utility commands 569 CFG_CMD_NET bootp, tftpboot, rarpboot 570 CFG_CMD_PCI * pciinfo 571 CFG_CMD_PCMCIA * PCMCIA support 572 CFG_CMD_REGINFO * Register dump 573 CFG_CMD_RUN run command in env variable 574 CFG_CMD_SCSI * SCSI Support 575 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 576 CFG_CMD_SPI * SPI serial bus support 577 CFG_CMD_USB * USB support 578 CFG_CMD_BSP * Board SPecific functions 579 ----------------------------------------------- 580 CFG_CMD_ALL all 581 582 CFG_CMD_DFL Default configuration; at the moment 583 this is includes all commands, except 584 the ones marked with "*" in the list 585 above. 586 587 If you don't define CONFIG_COMMANDS it defaults to 588 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 589 override the default settings in the respective 590 include file. 591 592 EXAMPLE: If you want all functions except of network 593 support you can write: 594 595 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 596 597 598 Note: Don't enable the "icache" and "dcache" commands 599 (configuration option CFG_CMD_CACHE) unless you know 600 what you (and your U-Boot users) are doing. Data 601 cache cannot be enabled on systems like the 8xx or 602 8260 (where accesses to the IMMR region must be 603 uncached), and it cannot be disabled on all other 604 systems where we (mis-) use the data cache to hold an 605 initial stack and some data. 606 607 608 XXX - this list needs to get updated! 609 610- Watchdog: 611 CONFIG_WATCHDOG 612 If this variable is defined, it enables watchdog 613 support. There must support in the platform specific 614 code for a watchdog. For the 8xx and 8260 CPUs, the 615 SIU Watchdog feature is enabled in the SYPCR 616 register. 617 618- Real-Time Clock: 619 620 When CFG_CMD_DATE is selected, the type of the RTC 621 has to be selected, too. Define exactly one of the 622 following options: 623 624 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 625 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 626 CONFIG_RTC_MC146818 - use MC146818 RTC 627 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 628 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 629 630- Timestamp Support: 631 632 When CONFIG_TIMESTAMP is selected, the timestamp 633 (date and time) of an image is printed by image 634 commands like bootm or iminfo. This option is 635 automatically enabled when you select CFG_CMD_DATE . 636 637- Partition Support: 638 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 639 and/or CONFIG_ISO_PARTITION 640 641 If IDE or SCSI support is enabled (CFG_CMD_IDE or 642 CFG_CMD_SCSI) you must configure support for at least 643 one partition type as well. 644 645- IDE Reset method: 646 CONFIG_IDE_RESET_ROUTINE 647 648 Set this to define that instead of a reset Pin, the 649 routine ide_set_reset(int idereset) will be used. 650 651- ATAPI Support: 652 CONFIG_ATAPI 653 654 Set this to enable ATAPI support. 655 656- SCSI Support: 657 At the moment only there is only support for the 658 SYM53C8XX SCSI controller; define 659 CONFIG_SCSI_SYM53C8XX to enable it. 660 661 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 662 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 663 CFG_SCSI_MAX_LUN] can be adjusted to define the 664 maximum numbers of LUNs, SCSI ID's and target 665 devices. 666 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 667 668- NETWORK Support (PCI): 669 CONFIG_EEPRO100 670 Support for Intel 82557/82559/82559ER chips. 671 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 672 write routine for first time initialisation. 673 674 CONFIG_TULIP 675 Support for Digital 2114x chips. 676 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 677 modem chip initialisation (KS8761/QS6611). 678 679 CONFIG_NATSEMI 680 Support for National dp83815 chips. 681 682 CONFIG_NS8382X 683 Support for National dp8382[01] gigabit chips. 684 685- USB Support: 686 At the moment only the UHCI host controller is 687 supported (PIP405, MIP405); define 688 CONFIG_USB_UHCI to enable it. 689 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 690 end define CONFIG_USB_STORAGE to enable the USB 691 storage devices. 692 Note: 693 Supported are USB Keyboards and USB Floppy drives 694 (TEAC FD-05PUB). 695 696- Keyboard Support: 697 CONFIG_ISA_KEYBOARD 698 699 Define this to enable standard (PC-Style) keyboard 700 support 701 702 CONFIG_I8042_KBD 703 Standard PC keyboard driver with US (is default) and 704 GERMAN key layout (switch via environment 'keymap=de') support. 705 Export function i8042_kbd_init, i8042_tstc and i8042_getc 706 for cfb_console. Supports cursor blinking. 707 708- Video support: 709 CONFIG_VIDEO 710 711 Define this to enable video support (for output to 712 video). 713 714 CONFIG_VIDEO_CT69000 715 716 Enable Chips & Technologies 69000 Video chip 717 718 CONFIG_VIDEO_SMI_LYNXEM 719 Enable Silicon Motion SMI 712/710/810 Video chip 720 Videomode are selected via environment 'videomode' with 721 standard LiLo mode numbers. 722 Following modes are supported (* is default): 723 724 800x600 1024x768 1280x1024 725 256 (8bit) 303* 305 307 726 65536 (16bit) 314 317 31a 727 16,7 Mill (24bit) 315 318 31b 728 (i.e. setenv videomode 317; saveenv; reset;) 729 730 CONFIG_VIDEO_SED13806 731 Enable Epson SED13806 driver. This driver supports 8bpp 732 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 733 or CONFIG_VIDEO_SED13806_16BPP 734 735 736- LCD Support: CONFIG_LCD 737 738 Define this to enable LCD support (for output to LCD 739 display); also select one of the supported displays 740 by defining one of these: 741 742 CONFIG_NEC_NL6648AC33: 743 744 NEC NL6648AC33-18. Active, color, single scan. 745 746 CONFIG_NEC_NL6648BC20 747 748 NEC NL6648BC20-08. 6.5", 640x480. 749 Active, color, single scan. 750 751 CONFIG_SHARP_16x9 752 753 Sharp 320x240. Active, color, single scan. 754 It isn't 16x9, and I am not sure what it is. 755 756 CONFIG_SHARP_LQ64D341 757 758 Sharp LQ64D341 display, 640x480. 759 Active, color, single scan. 760 761 CONFIG_HLD1045 762 763 HLD1045 display, 640x480. 764 Active, color, single scan. 765 766 CONFIG_OPTREX_BW 767 768 Optrex CBL50840-2 NF-FW 99 22 M5 769 or 770 Hitachi LMG6912RPFC-00T 771 or 772 Hitachi SP14Q002 773 774 320x240. Black & white. 775 776 Normally display is black on white background; define 777 CFG_WHITE_ON_BLACK to get it inverted. 778 779- Ethernet address: 780 CONFIG_ETHADDR 781 CONFIG_ETH2ADDR 782 CONFIG_ETH3ADDR 783 784 Define a default value for ethernet address to use 785 for the respective ethernet interface, in case this 786 is not determined automatically. 787 788- IP address: 789 CONFIG_IPADDR 790 791 Define a default value for the IP address to use for 792 the default ethernet interface, in case this is not 793 determined through e.g. bootp. 794 795- Server IP address: 796 CONFIG_SERVERIP 797 798 Defines a default value for theIP address of a TFTP 799 server to contact when using the "tftboot" command. 800 801- BOOTP Recovery Mode: 802 CONFIG_BOOTP_RANDOM_DELAY 803 804 If you have many targets in a network that try to 805 boot using BOOTP, you may want to avoid that all 806 systems send out BOOTP requests at precisely the same 807 moment (which would happen for instance at recovery 808 from a power failure, when all systems will try to 809 boot, thus flooding the BOOTP server. Defining 810 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 811 inserted before sending out BOOTP requests. The 812 following delays are insterted then: 813 814 1st BOOTP request: delay 0 ... 1 sec 815 2nd BOOTP request: delay 0 ... 2 sec 816 3rd BOOTP request: delay 0 ... 4 sec 817 4th and following 818 BOOTP requests: delay 0 ... 8 sec 819 820- Status LED: CONFIG_STATUS_LED 821 822 Several configurations allow to display the current 823 status using a LED. For instance, the LED will blink 824 fast while running U-Boot code, stop blinking as 825 soon as a reply to a BOOTP request was received, and 826 start blinking slow once the Linux kernel is running 827 (supported by a status LED driver in the Linux 828 kernel). Defining CONFIG_STATUS_LED enables this 829 feature in U-Boot. 830 831- CAN Support: CONFIG_CAN_DRIVER 832 833 Defining CONFIG_CAN_DRIVER enables CAN driver support 834 on those systems that support this (optional) 835 feature, like the TQM8xxL modules. 836 837- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 838 839 Enables I2C serial bus commands. If this is selected, 840 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 841 to include the appropriate I2C driver. 842 843 See also: common/cmd_i2c.c for a description of the 844 command line interface. 845 846 847 CONFIG_HARD_I2C 848 849 Selects the CPM hardware driver for I2C. 850 851 CONFIG_SOFT_I2C 852 853 Use software (aka bit-banging) driver instead of CPM 854 or similar hardware support for I2C. This is configured 855 via the following defines. 856 857 I2C_INIT 858 859 (Optional). Any commands necessary to enable I2C 860 controller or configure ports. 861 862 I2C_PORT 863 864 (Only for MPC8260 CPU). The I/O port to use (the code 865 assumes both bits are on the same port). Valid values 866 are 0..3 for ports A..D. 867 868 I2C_ACTIVE 869 870 The code necessary to make the I2C data line active 871 (driven). If the data line is open collector, this 872 define can be null. 873 874 I2C_TRISTATE 875 876 The code necessary to make the I2C data line tri-stated 877 (inactive). If the data line is open collector, this 878 define can be null. 879 880 I2C_READ 881 882 Code that returns TRUE if the I2C data line is high, 883 FALSE if it is low. 884 885 I2C_SDA(bit) 886 887 If <bit> is TRUE, sets the I2C data line high. If it 888 is FALSE, it clears it (low). 889 890 I2C_SCL(bit) 891 892 If <bit> is TRUE, sets the I2C clock line high. If it 893 is FALSE, it clears it (low). 894 895 I2C_DELAY 896 897 This delay is invoked four times per clock cycle so this 898 controls the rate of data transfer. The data rate thus 899 is 1 / (I2C_DELAY * 4). 900 901 CFG_I2C_INIT_BOARD 902 903 When a board is reset during an i2c bus transfer 904 chips might think that the current transfer is still 905 in progress. On some boards it is possible to access 906 the i2c SCLK line directly, either by using the 907 processor pin as a GPIO or by having a second pin 908 connected to the bus. If this option is defined a 909 custom i2c_init_board() routine in boards/xxx/board.c 910 is run early in the boot sequence. 911 912- SPI Support: CONFIG_SPI 913 914 Enables SPI driver (so far only tested with 915 SPI EEPROM, also an instance works with Crystal A/D and 916 D/As on the SACSng board) 917 918 CONFIG_SPI_X 919 920 Enables extended (16-bit) SPI EEPROM addressing. 921 (symmetrical to CONFIG_I2C_X) 922 923 CONFIG_SOFT_SPI 924 925 Enables a software (bit-bang) SPI driver rather than 926 using hardware support. This is a general purpose 927 driver that only requires three general I/O port pins 928 (two outputs, one input) to function. If this is 929 defined, the board configuration must define several 930 SPI configuration items (port pins to use, etc). For 931 an example, see include/configs/sacsng.h. 932 933- FPGA Support: CONFIG_FPGA_COUNT 934 935 Specify the number of FPGA devices to support. 936 937 CONFIG_FPGA 938 939 Used to specify the types of FPGA devices. For 940 example, 941 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 942 943 CFG_FPGA_PROG_FEEDBACK 944 945 Enable printing of hash marks during FPGA 946 configuration. 947 948 CFG_FPGA_CHECK_BUSY 949 950 Enable checks on FPGA configuration interface busy 951 status by the configuration function. This option 952 will require a board or device specific function to 953 be written. 954 955 CONFIG_FPGA_DELAY 956 957 If defined, a function that provides delays in the 958 FPGA configuration driver. 959 960 CFG_FPGA_CHECK_CTRLC 961 962 Allow Control-C to interrupt FPGA configuration 963 964 CFG_FPGA_CHECK_ERROR 965 966 Check for configuration errors during FPGA bitfile 967 loading. For example, abort during Virtex II 968 configuration if the INIT_B line goes low (which 969 indicated a CRC error). 970 971 CFG_FPGA_WAIT_INIT 972 973 Maximum time to wait for the INIT_B line to deassert 974 after PROB_B has been deasserted during a Virtex II 975 FPGA configuration sequence. The default time is 500 mS. 976 977 CFG_FPGA_WAIT_BUSY 978 979 Maximum time to wait for BUSY to deassert during 980 Virtex II FPGA configuration. The default is 5 mS. 981 982 CFG_FPGA_WAIT_CONFIG 983 984 Time to wait after FPGA configuration. The default is 985 200 mS. 986 987- FPGA Support: CONFIG_FPGA_COUNT 988 989 Specify the number of FPGA devices to support. 990 991 CONFIG_FPGA 992 993 Used to specify the types of FPGA devices. For example, 994 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 995 996 CFG_FPGA_PROG_FEEDBACK 997 998 Enable printing of hash marks during FPGA configuration. 999 1000 CFG_FPGA_CHECK_BUSY 1001 1002 Enable checks on FPGA configuration interface busy 1003 status by the configuration function. This option 1004 will require a board or device specific function to 1005 be written. 1006 1007 CONFIG_FPGA_DELAY 1008 1009 If defined, a function that provides delays in the FPGA 1010 configuration driver. 1011 1012 CFG_FPGA_CHECK_CTRLC 1013 Allow Control-C to interrupt FPGA configuration 1014 1015 CFG_FPGA_CHECK_ERROR 1016 1017 Check for configuration errors during FPGA bitfile 1018 loading. For example, abort during Virtex II 1019 configuration if the INIT_B line goes low (which 1020 indicated a CRC error). 1021 1022 CFG_FPGA_WAIT_INIT 1023 1024 Maximum time to wait for the INIT_B line to deassert 1025 after PROB_B has been deasserted during a Virtex II 1026 FPGA configuration sequence. The default time is 500 1027 mS. 1028 1029 CFG_FPGA_WAIT_BUSY 1030 1031 Maximum time to wait for BUSY to deassert during 1032 Virtex II FPGA configuration. The default is 5 mS. 1033 1034 CFG_FPGA_WAIT_CONFIG 1035 1036 Time to wait after FPGA configuration. The default is 1037 200 mS. 1038 1039- Configuration Management: 1040 CONFIG_IDENT_STRING 1041 1042 If defined, this string will be added to the U-Boot 1043 version information (U_BOOT_VERSION) 1044 1045- Vendor Parameter Protection: 1046 1047 U-Boot considers the values of the environment 1048 variables "serial#" (Board Serial Number) and 1049 "ethaddr" (Ethernet Address) to bb parameters that 1050 are set once by the board vendor / manufacturer, and 1051 protects these variables from casual modification by 1052 the user. Once set, these variables are read-only, 1053 and write or delete attempts are rejected. You can 1054 change this behviour: 1055 1056 If CONFIG_ENV_OVERWRITE is #defined in your config 1057 file, the write protection for vendor parameters is 1058 completely disabled. Anybody can change or delete 1059 these parameters. 1060 1061 Alternatively, if you #define _both_ CONFIG_ETHADDR 1062 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1063 ethernet address is installed in the environment, 1064 which can be changed exactly ONCE by the user. [The 1065 serial# is unaffected by this, i. e. it remains 1066 read-only.] 1067 1068- Protected RAM: 1069 CONFIG_PRAM 1070 1071 Define this variable to enable the reservation of 1072 "protected RAM", i. e. RAM which is not overwritten 1073 by U-Boot. Define CONFIG_PRAM to hold the number of 1074 kB you want to reserve for pRAM. You can overwrite 1075 this default value by defining an environment 1076 variable "pram" to the number of kB you want to 1077 reserve. Note that the board info structure will 1078 still show the full amount of RAM. If pRAM is 1079 reserved, a new environment variable "mem" will 1080 automatically be defined to hold the amount of 1081 remaining RAM in a form that can be passed as boot 1082 argument to Linux, for instance like that: 1083 1084 setenv bootargs ... mem=\$(mem) 1085 saveenv 1086 1087 This way you can tell Linux not to use this memory, 1088 either, which results in a memory region that will 1089 not be affected by reboots. 1090 1091 *WARNING* If your board configuration uses automatic 1092 detection of the RAM size, you must make sure that 1093 this memory test is non-destructive. So far, the 1094 following board configurations are known to be 1095 "pRAM-clean": 1096 1097 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1098 HERMES, IP860, RPXlite, LWMON, LANTEC, 1099 PCU_E, FLAGADM, TQM8260 1100 1101- Error Recovery: 1102 CONFIG_PANIC_HANG 1103 1104 Define this variable to stop the system in case of a 1105 fatal error, so that you have to reset it manually. 1106 This is probably NOT a good idea for an embedded 1107 system where you want to system to reboot 1108 automatically as fast as possible, but it may be 1109 useful during development since you can try to debug 1110 the conditions that lead to the situation. 1111 1112 CONFIG_NET_RETRY_COUNT 1113 1114 This variable defines the number of retries for 1115 network operations like ARP, RARP, TFTP, or BOOTP 1116 before giving up the operation. If not defined, a 1117 default value of 5 is used. 1118 1119- Command Interpreter: 1120 CFG_HUSH_PARSER 1121 1122 Define this variable to enable the "hush" shell (from 1123 Busybox) as command line interpreter, thus enabling 1124 powerful command line syntax like 1125 if...then...else...fi conditionals or `&&' and '||' 1126 constructs ("shell scripts"). 1127 1128 If undefined, you get the old, much simpler behaviour 1129 with a somewhat smaller memory footprint. 1130 1131 1132 CFG_PROMPT_HUSH_PS2 1133 1134 This defines the secondary prompt string, which is 1135 printed when the command interpreter needs more input 1136 to complete a command. Usually "> ". 1137 1138 Note: 1139 1140 In the current implementation, the local variables 1141 space and global environment variables space are 1142 separated. Local variables are those you define by 1143 simply typing like `name=value'. To access a local 1144 variable later on, you have write `$name' or 1145 `${name}'; variable directly by typing say `$name' at 1146 the command prompt. 1147 1148 Global environment variables are those you use 1149 setenv/printenv to work with. To run a command stored 1150 in such a variable, you need to use the run command, 1151 and you must not use the '$' sign to access them. 1152 1153 To store commands and special characters in a 1154 variable, please use double quotation marks 1155 surrounding the whole text of the variable, instead 1156 of the backslashes before semicolons and special 1157 symbols. 1158 1159- Default Environment 1160 CONFIG_EXTRA_ENV_SETTINGS 1161 1162 Define this to contain any number of null terminated 1163 strings (variable = value pairs) that will be part of 1164 the default enviroment compiled into the boot image. 1165 1166 For example, place something like this in your 1167 board's config file: 1168 1169 #define CONFIG_EXTRA_ENV_SETTINGS \ 1170 "myvar1=value1\0" \ 1171 "myvar2=value2\0" 1172 1173 Warning: This method is based on knowledge about the 1174 internal format how the environment is stored by the 1175 U-Boot code. This is NOT an official, exported 1176 interface! Although it is unlikely that this format 1177 will change soon, but there is no guarantee either. 1178 You better know what you are doing here. 1179 1180 Note: overly (ab)use of the default environment is 1181 discouraged. Make sure to check other ways to preset 1182 the environment like the autoscript function or the 1183 boot command first. 1184 1185- Show boot progress 1186 CONFIG_SHOW_BOOT_PROGRESS 1187 1188 Defining this option allows to add some board- 1189 specific code (calling a user-provided function 1190 "show_boot_progress(int)") that enables you to show 1191 the system's boot progress on some display (for 1192 example, some LED's) on your board. At the moment, 1193 the following checkpoints are implemented: 1194 1195 Arg Where When 1196 1 common/cmd_bootm.c before attempting to boot an image 1197 -1 common/cmd_bootm.c Image header has bad magic number 1198 2 common/cmd_bootm.c Image header has correct magic number 1199 -2 common/cmd_bootm.c Image header has bad checksum 1200 3 common/cmd_bootm.c Image header has correct checksum 1201 -3 common/cmd_bootm.c Image data has bad checksum 1202 4 common/cmd_bootm.c Image data has correct checksum 1203 -4 common/cmd_bootm.c Image is for unsupported architecture 1204 5 common/cmd_bootm.c Architecture check OK 1205 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1206 6 common/cmd_bootm.c Image Type check OK 1207 -6 common/cmd_bootm.c gunzip uncompression error 1208 -7 common/cmd_bootm.c Unimplemented compression type 1209 7 common/cmd_bootm.c Uncompression OK 1210 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1211 8 common/cmd_bootm.c Image Type check OK 1212 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1213 9 common/cmd_bootm.c Start initial ramdisk verification 1214 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1215 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1216 10 common/cmd_bootm.c Ramdisk header is OK 1217 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1218 11 common/cmd_bootm.c Ramdisk data has correct checksum 1219 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1220 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1221 13 common/cmd_bootm.c Start multifile image verification 1222 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1223 15 common/cmd_bootm.c All preparation done, transferring control to OS 1224 1225 -1 common/cmd_doc.c Bad usage of "doc" command 1226 -1 common/cmd_doc.c No boot device 1227 -1 common/cmd_doc.c Unknown Chip ID on boot device 1228 -1 common/cmd_doc.c Read Error on boot device 1229 -1 common/cmd_doc.c Image header has bad magic number 1230 1231 -1 common/cmd_ide.c Bad usage of "ide" command 1232 -1 common/cmd_ide.c No boot device 1233 -1 common/cmd_ide.c Unknown boot device 1234 -1 common/cmd_ide.c Unknown partition table 1235 -1 common/cmd_ide.c Invalid partition type 1236 -1 common/cmd_ide.c Read Error on boot device 1237 -1 common/cmd_ide.c Image header has bad magic number 1238 1239 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1240 1241 1242Modem Support: 1243-------------- 1244 1245[so far only for SMDK2400 board] 1246 1247- Modem support endable: 1248 CONFIG_MODEM_SUPPORT 1249 1250- RTS/CTS Flow control enable: 1251 CONFIG_HWFLOW 1252 1253- Modem debug support: 1254 CONFIG_MODEM_SUPPORT_DEBUG 1255 1256 Enables debugging stuff (char screen[1024], dbg()) 1257 for modem support. Useful only with BDI2000. 1258 1259- General: 1260 1261 In the target system modem support is enabled when a 1262 specific key (key combination) is pressed during 1263 power-on. Otherwise U-Boot will boot normally 1264 (autoboot). The key_pressed() fuction is called from 1265 board_init(). Currently key_pressed() is a dummy 1266 function, returning 1 and thus enabling modem 1267 initialization. 1268 1269 If there are no modem init strings in the 1270 environment, U-Boot proceed to autoboot; the 1271 previous output (banner, info printfs) will be 1272 supressed, though. 1273 1274 See also: doc/README.Modem 1275 1276 1277 1278 1279Configuration Settings: 1280----------------------- 1281 1282- CFG_LONGHELP: Defined when you want long help messages included; 1283 undefine this when you're short of memory. 1284 1285- CFG_PROMPT: This is what U-Boot prints on the console to 1286 prompt for user input. 1287 1288- CFG_CBSIZE: Buffer size for input from the Console 1289 1290- CFG_PBSIZE: Buffer size for Console output 1291 1292- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1293 1294- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1295 the application (usually a Linux kernel) when it is 1296 booted 1297 1298- CFG_BAUDRATE_TABLE: 1299 List of legal baudrate settings for this board. 1300 1301- CFG_CONSOLE_INFO_QUIET 1302 Suppress display of console information at boot. 1303 1304- CFG_CONSOLE_IS_IN_ENV 1305 If the board specific function 1306 extern int overwrite_console (void); 1307 returns 1, the stdin, stderr and stdout are switched to the 1308 serial port, else the settings in the environment are used. 1309 1310- CFG_CONSOLE_OVERWRITE_ROUTINE 1311 Enable the call to overwrite_console(). 1312 1313- CFG_CONSOLE_ENV_OVERWRITE 1314 Enable overwrite of previous console environment settings. 1315 1316- CFG_MEMTEST_START, CFG_MEMTEST_END: 1317 Begin and End addresses of the area used by the 1318 simple memory test. 1319 1320- CFG_ALT_MEMTEST: 1321 Enable an alternate, more extensive memory test. 1322 1323- CFG_TFTP_LOADADDR: 1324 Default load address for network file downloads 1325 1326- CFG_LOADS_BAUD_CHANGE: 1327 Enable temporary baudrate change while serial download 1328 1329- CFG_SDRAM_BASE: 1330 Physical start address of SDRAM. _Must_ be 0 here. 1331 1332- CFG_MBIO_BASE: 1333 Physical start address of Motherboard I/O (if using a 1334 Cogent motherboard) 1335 1336- CFG_FLASH_BASE: 1337 Physical start address of Flash memory. 1338 1339- CFG_MONITOR_BASE: 1340 Physical start address of boot monitor code (set by 1341 make config files to be same as the text base address 1342 (TEXT_BASE) used when linking) - same as 1343 CFG_FLASH_BASE when booting from flash. 1344 1345- CFG_MONITOR_LEN: 1346 Size of memory reserved for monitor code 1347 1348- CFG_MALLOC_LEN: 1349 Size of DRAM reserved for malloc() use. 1350 1351- CFG_BOOTMAPSZ: 1352 Maximum size of memory mapped by the startup code of 1353 the Linux kernel; all data that must be processed by 1354 the Linux kernel (bd_info, boot arguments, eventually 1355 initrd image) must be put below this limit. 1356 1357- CFG_MAX_FLASH_BANKS: 1358 Max number of Flash memory banks 1359 1360- CFG_MAX_FLASH_SECT: 1361 Max number of sectors on a Flash chip 1362 1363- CFG_FLASH_ERASE_TOUT: 1364 Timeout for Flash erase operations (in ms) 1365 1366- CFG_FLASH_WRITE_TOUT: 1367 Timeout for Flash write operations (in ms) 1368 1369- CFG_DIRECT_FLASH_TFTP: 1370 1371 Enable TFTP transfers directly to flash memory; 1372 without this option such a download has to be 1373 performed in two steps: (1) download to RAM, and (2) 1374 copy from RAM to flash. 1375 1376 The two-step approach is usually more reliable, since 1377 you can check if the download worked before you erase 1378 the flash, but in some situations (when sytem RAM is 1379 too limited to allow for a tempory copy of the 1380 downloaded image) this option may be very useful. 1381 1382- CFG_FLASH_CFI: 1383 Define if the flash driver uses extra elements in the 1384 common flash structure for storing flash geometry 1385 1386The following definitions that deal with the placement and management 1387of environment data (variable area); in general, we support the 1388following configurations: 1389 1390- CFG_ENV_IS_IN_FLASH: 1391 1392 Define this if the environment is in flash memory. 1393 1394 a) The environment occupies one whole flash sector, which is 1395 "embedded" in the text segment with the U-Boot code. This 1396 happens usually with "bottom boot sector" or "top boot 1397 sector" type flash chips, which have several smaller 1398 sectors at the start or the end. For instance, such a 1399 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1400 such a case you would place the environment in one of the 1401 4 kB sectors - with U-Boot code before and after it. With 1402 "top boot sector" type flash chips, you would put the 1403 environment in one of the last sectors, leaving a gap 1404 between U-Boot and the environment. 1405 1406 - CFG_ENV_OFFSET: 1407 1408 Offset of environment data (variable area) to the 1409 beginning of flash memory; for instance, with bottom boot 1410 type flash chips the second sector can be used: the offset 1411 for this sector is given here. 1412 1413 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1414 1415 - CFG_ENV_ADDR: 1416 1417 This is just another way to specify the start address of 1418 the flash sector containing the environment (instead of 1419 CFG_ENV_OFFSET). 1420 1421 - CFG_ENV_SECT_SIZE: 1422 1423 Size of the sector containing the environment. 1424 1425 1426 b) Sometimes flash chips have few, equal sized, BIG sectors. 1427 In such a case you don't want to spend a whole sector for 1428 the environment. 1429 1430 - CFG_ENV_SIZE: 1431 1432 If you use this in combination with CFG_ENV_IS_IN_FLASH 1433 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1434 of this flash sector for the environment. This saves 1435 memory for the RAM copy of the environment. 1436 1437 It may also save flash memory if you decide to use this 1438 when your environment is "embedded" within U-Boot code, 1439 since then the remainder of the flash sector could be used 1440 for U-Boot code. It should be pointed out that this is 1441 STRONGLY DISCOURAGED from a robustness point of view: 1442 updating the environment in flash makes it always 1443 necessary to erase the WHOLE sector. If something goes 1444 wrong before the contents has been restored from a copy in 1445 RAM, your target system will be dead. 1446 1447 - CFG_ENV_ADDR_REDUND 1448 CFG_ENV_SIZE_REDUND 1449 1450 These settings describe a second storage area used to hold 1451 a redundand copy of the environment data, so that there is 1452 a valid backup copy in case there is a power failur during 1453 a "saveenv" operation. 1454 1455BE CAREFUL! Any changes to the flash layout, and some changes to the 1456source code will make it necessary to adapt <board>/u-boot.lds* 1457accordingly! 1458 1459 1460- CFG_ENV_IS_IN_NVRAM: 1461 1462 Define this if you have some non-volatile memory device 1463 (NVRAM, battery buffered SRAM) which you want to use for the 1464 environment. 1465 1466 - CFG_ENV_ADDR: 1467 - CFG_ENV_SIZE: 1468 1469 These two #defines are used to determin the memory area you 1470 want to use for environment. It is assumed that this memory 1471 can just be read and written to, without any special 1472 provision. 1473 1474BE CAREFUL! The first access to the environment happens quite early 1475in U-Boot initalization (when we try to get the setting of for the 1476console baudrate). You *MUST* have mappend your NVRAM area then, or 1477U-Boot will hang. 1478 1479Please note that even with NVRAM we still use a copy of the 1480environment in RAM: we could work on NVRAM directly, but we want to 1481keep settings there always unmodified except somebody uses "saveenv" 1482to save the current settings. 1483 1484 1485- CFG_ENV_IS_IN_EEPROM: 1486 1487 Use this if you have an EEPROM or similar serial access 1488 device and a driver for it. 1489 1490 - CFG_ENV_OFFSET: 1491 - CFG_ENV_SIZE: 1492 1493 These two #defines specify the offset and size of the 1494 environment area within the total memory of your EEPROM. 1495 1496 - CFG_I2C_EEPROM_ADDR: 1497 If defined, specified the chip address of the EEPROM device. 1498 The default address is zero. 1499 1500 - CFG_EEPROM_PAGE_WRITE_BITS: 1501 If defined, the number of bits used to address bytes in a 1502 single page in the EEPROM device. A 64 byte page, for example 1503 would require six bits. 1504 1505 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1506 If defined, the number of milliseconds to delay between 1507 page writes. The default is zero milliseconds. 1508 1509 - CFG_I2C_EEPROM_ADDR_LEN: 1510 The length in bytes of the EEPROM memory array address. Note 1511 that this is NOT the chip address length! 1512 1513 - CFG_EEPROM_SIZE: 1514 The size in bytes of the EEPROM device. 1515 1516 1517- CFG_SPI_INIT_OFFSET 1518 1519 Defines offset to the initial SPI buffer area in DPRAM. The 1520 area is used at an early stage (ROM part) if the environment 1521 is configured to reside in the SPI EEPROM: We need a 520 byte 1522 scratch DPRAM area. It is used between the two initialization 1523 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1524 to be a good choice since it makes it far enough from the 1525 start of the data area as well as from the stack pointer. 1526 1527Please note that the environment is read-only as long as the monitor 1528has been relocated to RAM and a RAM copy of the environment has been 1529created; also, when using EEPROM you will have to use getenv_r() 1530until then to read environment variables. 1531 1532The environment is now protected by a CRC32 checksum. Before the 1533monitor is relocated into RAM, as a result of a bad CRC you will be 1534working with the compiled-in default environment - *silently*!!! 1535[This is necessary, because the first environment variable we need is 1536the "baudrate" setting for the console - if we have a bad CRC, we 1537don't have any device yet where we could complain.] 1538 1539Note: once the monitor has been relocated, then it will complain if 1540the default environment is used; a new CRC is computed as soon as you 1541use the "setenv" command to modify / delete / add any environment 1542variable [even when you try to delete a non-existing variable!]. 1543 1544Note2: you must edit your u-boot.lds file to reflect this 1545configuration. 1546 1547 1548Low Level (hardware related) configuration options: 1549 1550- CFG_CACHELINE_SIZE: 1551 Cache Line Size of the CPU. 1552 1553- CFG_DEFAULT_IMMR: 1554 Default address of the IMMR after system reset. 1555 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1556 to be able to adjust the position of the IMMR 1557 register after a reset. 1558 1559- Floppy Disk Support: 1560 CFG_FDC_DRIVE_NUMBER 1561 1562 the default drive number (default value 0) 1563 1564 CFG_ISA_IO_STRIDE 1565 1566 defines the spacing between fdc chipset registers 1567 (default value 1) 1568 1569 CFG_ISA_IO_OFFSET 1570 1571 defines the offset of register from address. It 1572 depends on which part of the data bus is connected to 1573 the fdc chipset. (default value 0) 1574 1575 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1576 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1577 default value. 1578 1579 if CFG_FDC_HW_INIT is defined, then the function 1580 fdc_hw_init() is called at the beginning of the FDC 1581 setup. fdc_hw_init() must be provided by the board 1582 source code. It is used to make hardware dependant 1583 initializations. 1584 1585- CFG_IMMR: Physical address of the Internal Memory Mapped 1586 Register; DO NOT CHANGE! (11-4) 1587 [MPC8xx systems only] 1588 1589- CFG_INIT_RAM_ADDR: 1590 1591 Start address of memory area tha can be used for 1592 initial data and stack; please note that this must be 1593 writable memory that is working WITHOUT special 1594 initialization, i. e. you CANNOT use normal RAM which 1595 will become available only after programming the 1596 memory controller and running certain initialization 1597 sequences. 1598 1599 U-Boot uses the following memory types: 1600 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1601 - MPC824X: data cache 1602 - PPC4xx: data cache 1603 1604- CFG_INIT_DATA_OFFSET: 1605 1606 Offset of the initial data structure in the memory 1607 area defined by CFG_INIT_RAM_ADDR. Usually 1608 CFG_INIT_DATA_OFFSET is chosen such that the initial 1609 data is located at the end of the available space 1610 (sometimes written as (CFG_INIT_RAM_END - 1611 CFG_INIT_DATA_SIZE), and the initial stack is just 1612 below that area (growing from (CFG_INIT_RAM_ADDR + 1613 CFG_INIT_DATA_OFFSET) downward. 1614 1615 Note: 1616 On the MPC824X (or other systems that use the data 1617 cache for initial memory) the address chosen for 1618 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1619 point to an otherwise UNUSED address space between 1620 the top of RAM and the start of the PCI space. 1621 1622- CFG_SIUMCR: SIU Module Configuration (11-6) 1623 1624- CFG_SYPCR: System Protection Control (11-9) 1625 1626- CFG_TBSCR: Time Base Status and Control (11-26) 1627 1628- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1629 1630- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1631 1632- CFG_SCCR: System Clock and reset Control Register (15-27) 1633 1634- CFG_OR_TIMING_SDRAM: 1635 SDRAM timing 1636 1637- CFG_MAMR_PTA: 1638 periodic timer for refresh 1639 1640- CFG_DER: Debug Event Register (37-47) 1641 1642- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1643 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1644 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1645 CFG_BR1_PRELIM: 1646 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1647 1648- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1649 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1650 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1651 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1652 1653- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1654 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1655 Machine Mode Register and Memory Periodic Timer 1656 Prescaler definitions (SDRAM timing) 1657 1658- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1659 enable I2C microcode relocation patch (MPC8xx); 1660 define relocation offset in DPRAM [DSP2] 1661 1662- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1663 enable SPI microcode relocation patch (MPC8xx); 1664 define relocation offset in DPRAM [SCC4] 1665 1666- CFG_USE_OSCCLK: 1667 Use OSCM clock mode on MBX8xx board. Be careful, 1668 wrong setting might damage your board. Read 1669 doc/README.MBX before setting this variable! 1670 1671- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1672 Offset of the bootmode word in DPRAM used by post 1673 (Power On Self Tests). This definition overrides 1674 #define'd default value in commproc.h resp. 1675 cpm_8260.h. 1676 1677Building the Software: 1678====================== 1679 1680Building U-Boot has been tested in native PPC environments (on a 1681PowerBook G3 running LinuxPPC 2000) and in cross environments 1682(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1683NetBSD 1.5 on x86). 1684 1685If you are not using a native PPC environment, it is assumed that you 1686have the GNU cross compiling tools available in your path and named 1687with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1688you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1689the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1690change it to: 1691 1692 CROSS_COMPILE = ppc_4xx- 1693 1694 1695U-Boot is intended to be simple to build. After installing the 1696sources you must configure U-Boot for one specific board type. This 1697is done by typing: 1698 1699 make NAME_config 1700 1701where "NAME_config" is the name of one of the existing 1702configurations; the following names are supported: 1703 1704 ADCIOP_config GTH_config TQM850L_config 1705 ADS860_config IP860_config TQM855L_config 1706 AR405_config IVML24_config TQM860L_config 1707 CANBT_config IVMS8_config WALNUT405_config 1708 CPCI405_config LANTEC_config cogent_common_config 1709 CPCIISER4_config MBX_config cogent_mpc8260_config 1710 CU824_config MBX860T_config cogent_mpc8xx_config 1711 ESTEEM192E_config RPXlite_config hermes_config 1712 ETX094_config RPXsuper_config hymod_config 1713 FADS823_config SM850_config lwmon_config 1714 FADS850SAR_config SPD823TS_config pcu_e_config 1715 FADS860T_config SXNI855T_config rsdproto_config 1716 FPS850L_config Sandpoint8240_config sbc8260_config 1717 GENIETV_config TQM823L_config PIP405_config 1718 GEN860T_config EBONY_config FPS860L_config 1719 1720Note: for some board special configuration names may exist; check if 1721 additional information is available from the board vendor; for 1722 instance, the TQM8xxL systems run normally at 50 MHz and use a 1723 SCC for 10baseT ethernet; there are also systems with 80 MHz 1724 CPU clock, and an optional Fast Ethernet module is available 1725 for CPU's with FEC. You can select such additional "features" 1726 when chosing the configuration, i. e. 1727 1728 make TQM860L_config 1729 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1730 1731 make TQM860L_FEC_config 1732 - will configure for a TQM860L at 50MHz with FEC for ethernet 1733 1734 make TQM860L_80MHz_config 1735 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1736 interface 1737 1738 make TQM860L_FEC_80MHz_config 1739 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1740 1741 make TQM823L_LCD_config 1742 - will configure for a TQM823L with U-Boot console on LCD 1743 1744 make TQM823L_LCD_80MHz_config 1745 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1746 1747 etc. 1748 1749 1750 1751Finally, type "make all", and you should get some working U-Boot 1752images ready for downlod to / installation on your system: 1753 1754- "u-boot.bin" is a raw binary image 1755- "u-boot" is an image in ELF binary format 1756- "u-boot.srec" is in Motorola S-Record format 1757 1758 1759Please be aware that the Makefiles assume you are using GNU make, so 1760for instance on NetBSD you might need to use "gmake" instead of 1761native "make". 1762 1763 1764If the system board that you have is not listed, then you will need 1765to port U-Boot to your hardware platform. To do this, follow these 1766steps: 1767 17681. Add a new configuration option for your board to the toplevel 1769 "Makefile", using the existing entries as examples. 17702. Create a new directory to hold your board specific code. Add any 1771 files you need. 17723. If you're porting U-Boot to a new CPU, then also create a new 1773 directory to hold your CPU specific code. Add any files you need. 17744. Run "make config_name" with your new name. 17755. Type "make", and you should get a working "u-boot.srec" file 1776 to be installed on your target system. 1777 [Of course, this last step is much harder than it sounds.] 1778 1779 1780Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1781============================================================== 1782 1783If you have modified U-Boot sources (for instance added a new board 1784or support for new devices, a new CPU, etc.) you are expected to 1785provide feedback to the other developers. The feedback normally takes 1786the form of a "patch", i. e. a context diff against a certain (latest 1787official or latest in CVS) version of U-Boot sources. 1788 1789But before you submit such a patch, please verify that your modifi- 1790cation did not break existing code. At least make sure that *ALL* of 1791the supported boards compile WITHOUT ANY compiler warnings. To do so, 1792just run the "MAKEALL" script, which will configure and build U-Boot 1793for ALL supported system. Be warned, this will take a while. You can 1794select which (cross) compiler to use py passing a `CROSS_COMPILE' 1795environment variable to the script, i. e. to use the cross tools from 1796MontaVista's Hard Hat Linux you can type 1797 1798 CROSS_COMPILE=ppc_8xx- MAKEALL 1799 1800or to build on a native PowerPC system you can type 1801 1802 CROSS_COMPILE=' ' MAKEALL 1803 1804See also "U-Boot Porting Guide" below. 1805 1806 1807 1808Monitor Commands - Overview: 1809============================ 1810 1811go - start application at address 'addr' 1812run - run commands in an environment variable 1813bootm - boot application image from memory 1814bootp - boot image via network using BootP/TFTP protocol 1815tftpboot- boot image via network using TFTP protocol 1816 and env variables "ipaddr" and "serverip" 1817 (and eventually "gatewayip") 1818rarpboot- boot image via network using RARP/TFTP protocol 1819diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1820loads - load S-Record file over serial line 1821loadb - load binary file over serial line (kermit mode) 1822md - memory display 1823mm - memory modify (auto-incrementing) 1824nm - memory modify (constant address) 1825mw - memory write (fill) 1826cp - memory copy 1827cmp - memory compare 1828crc32 - checksum calculation 1829imd - i2c memory display 1830imm - i2c memory modify (auto-incrementing) 1831inm - i2c memory modify (constant address) 1832imw - i2c memory write (fill) 1833icrc32 - i2c checksum calculation 1834iprobe - probe to discover valid I2C chip addresses 1835iloop - infinite loop on address range 1836isdram - print SDRAM configuration information 1837sspi - SPI utility commands 1838base - print or set address offset 1839printenv- print environment variables 1840setenv - set environment variables 1841saveenv - save environment variables to persistent storage 1842protect - enable or disable FLASH write protection 1843erase - erase FLASH memory 1844flinfo - print FLASH memory information 1845bdinfo - print Board Info structure 1846iminfo - print header information for application image 1847coninfo - print console devices and informations 1848ide - IDE sub-system 1849loop - infinite loop on address range 1850mtest - simple RAM test 1851icache - enable or disable instruction cache 1852dcache - enable or disable data cache 1853reset - Perform RESET of the CPU 1854echo - echo args to console 1855version - print monitor version 1856help - print online help 1857? - alias for 'help' 1858 1859 1860Monitor Commands - Detailed Description: 1861======================================== 1862 1863TODO. 1864 1865For now: just type "help <command>". 1866 1867 1868Environment Variables: 1869====================== 1870 1871U-Boot supports user configuration using Environment Variables which 1872can be made persistent by saving to Flash memory. 1873 1874Environment Variables are set using "setenv", printed using 1875"printenv", and saved to Flash using "saveenv". Using "setenv" 1876without a value can be used to delete a variable from the 1877environment. As long as you don't save the environment you are 1878working with an in-memory copy. In case the Flash area containing the 1879environment is erased by accident, a default environment is provided. 1880 1881Some configuration options can be set using Environment Variables: 1882 1883 baudrate - see CONFIG_BAUDRATE 1884 1885 bootdelay - see CONFIG_BOOTDELAY 1886 1887 bootcmd - see CONFIG_BOOTCOMMAND 1888 1889 bootargs - Boot arguments when booting an RTOS image 1890 1891 bootfile - Name of the image to load with TFTP 1892 1893 autoload - if set to "no" (any string beginning with 'n'), 1894 "bootp" will just load perform a lookup of the 1895 configuration from the BOOTP server, but not try to 1896 load any image using TFTP 1897 1898 autostart - if set to "yes", an image loaded using the "bootp", 1899 "rarpboot", "tftpboot" or "diskboot" commands will 1900 be automatically started (by internally calling 1901 "bootm") 1902 1903 initrd_high - restrict positioning of initrd images: 1904 If this variable is not set, initrd images will be 1905 copied to the highest possible address in RAM; this 1906 is usually what you want since it allows for 1907 maximum initrd size. If for some reason you want to 1908 make sure that the initrd image is loaded below the 1909 CFG_BOOTMAPSZ limit, you can set this environment 1910 variable to a value of "no" or "off" or "0". 1911 Alternatively, you can set it to a maximum upper 1912 address to use (U-Boot will still check that it 1913 does not overwrite the U-Boot stack and data). 1914 1915 For instance, when you have a system with 16 MB 1916 RAM, and want to reseve 4 MB from use by Linux, 1917 you can do this by adding "mem=12M" to the value of 1918 the "bootargs" variable. However, now you must make 1919 sure, that the initrd image is placed in the first 1920 12 MB as well - this can be done with 1921 1922 setenv initrd_high 00c00000 1923 1924 ipaddr - IP address; needed for tftpboot command 1925 1926 loadaddr - Default load address for commands like "bootp", 1927 "rarpboot", "tftpboot" or "diskboot" 1928 1929 loads_echo - see CONFIG_LOADS_ECHO 1930 1931 serverip - TFTP server IP address; needed for tftpboot command 1932 1933 bootretry - see CONFIG_BOOT_RETRY_TIME 1934 1935 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1936 1937 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1938 1939 1940The following environment variables may be used and automatically 1941updated by the network boot commands ("bootp" and "rarpboot"), 1942depending the information provided by your boot server: 1943 1944 bootfile - see above 1945 dnsip - IP address of your Domain Name Server 1946 gatewayip - IP address of the Gateway (Router) to use 1947 hostname - Target hostname 1948 ipaddr - see above 1949 netmask - Subnet Mask 1950 rootpath - Pathname of the root filesystem on the NFS server 1951 serverip - see above 1952 1953 1954There are two special Environment Variables: 1955 1956 serial# - contains hardware identification information such 1957 as type string and/or serial number 1958 ethaddr - Ethernet address 1959 1960These variables can be set only once (usually during manufacturing of 1961the board). U-Boot refuses to delete or overwrite these variables 1962once they have been set once. 1963 1964 1965Please note that changes to some configuration parameters may take 1966only effect after the next boot (yes, that's just like Windoze :-). 1967 1968 1969Note for Redundant Ethernet Interfaces: 1970======================================= 1971 1972Some boards come with redundand ethernet interfaces; U-Boot supports 1973such configurations and is capable of automatic selection of a 1974"working" interface when needed. MAC assignemnt works as follows: 1975 1976Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1977MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1978"eth1addr" (=>eth1), "eth2addr", ... 1979 1980If the network interface stores some valid MAC address (for instance 1981in SROM), this is used as default address if there is NO correspon- 1982ding setting in the environment; if the corresponding environment 1983variable is set, this overrides the settings in the card; that means: 1984 1985o If the SROM has a valid MAC address, and there is no address in the 1986 environment, the SROM's address is used. 1987 1988o If there is no valid address in the SROM, and a definition in the 1989 environment exists, then the value from the environment variable is 1990 used. 1991 1992o If both the SROM and the environment contain a MAC address, and 1993 both addresses are the same, this MAC address is used. 1994 1995o If both the SROM and the environment contain a MAC address, and the 1996 addresses differ, the value from the environment is used and a 1997 warning is printed. 1998 1999o If neither SROM nor the environment contain a MAC address, an error 2000 is raised. 2001 2002 2003 2004Image Formats: 2005============== 2006 2007The "boot" commands of this monitor operate on "image" files which 2008can be basicly anything, preceeded by a special header; see the 2009definitions in include/image.h for details; basicly, the header 2010defines the following image properties: 2011 2012* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2013 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2014 LynxOS, pSOS, QNX; 2015 Currently supported: Linux, NetBSD, VxWorks, QNX). 2016* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2017 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2018 Currently supported: PowerPC). 2019* Compression Type (Provisions for uncompressed, gzip, bzip2; 2020 Currently supported: uncompressed, gzip). 2021* Load Address 2022* Entry Point 2023* Image Name 2024* Image Timestamp 2025 2026The header is marked by a special Magic Number, and both the header 2027and the data portions of the image are secured against corruption by 2028CRC32 checksums. 2029 2030 2031Linux Support: 2032============== 2033 2034Although U-Boot should support any OS or standalone application 2035easily, Linux has always been in the focus during the design of 2036U-Boot. 2037 2038U-Boot includes many features that so far have been part of some 2039special "boot loader" code within the Linux kernel. Also, any 2040"initrd" images to be used are no longer part of one big Linux image; 2041instead, kernel and "initrd" are separate images. This implementation 2042serves serveral purposes: 2043 2044- the same features can be used for other OS or standalone 2045 applications (for instance: using compressed images to reduce the 2046 Flash memory footprint) 2047 2048- it becomes much easier to port new Linux kernel versions because 2049 lots of low-level, hardware dependend stuff are done by U-Boot 2050 2051- the same Linux kernel image can now be used with different "initrd" 2052 images; of course this also means that different kernel images can 2053 be run with the same "initrd". This makes testing easier (you don't 2054 have to build a new "zImage.initrd" Linux image when you just 2055 change a file in your "initrd"). Also, a field-upgrade of the 2056 software is easier now. 2057 2058 2059Linux HOWTO: 2060============ 2061 2062Porting Linux to U-Boot based systems: 2063--------------------------------------- 2064 2065U-Boot cannot save you from doing all the necessary modifications to 2066configure the Linux device drivers for use with your target hardware 2067(no, we don't intend to provide a full virtual machine interface to 2068Linux :-). 2069 2070But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2071 2072Just make sure your machine specific header file (for instance 2073include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2074Information structure as we define in include/u-boot.h, and make 2075sure that your definition of IMAP_ADDR uses the same value as your 2076U-Boot configuration in CFG_IMMR. 2077 2078 2079Configuring the Linux kernel: 2080----------------------------- 2081 2082No specific requirements for U-Boot. Make sure you have some root 2083device (initial ramdisk, NFS) for your target system. 2084 2085 2086Building a Linux Image: 2087----------------------- 2088 2089With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2090not used. If you use recent kernel source, a new build target 2091"uImage" will exist which automatically builds an image usable by 2092U-Boot. Most older kernels also have support for a "pImage" target, 2093which was introduced for our predecessor project PPCBoot and uses a 2094100% compatible format. 2095 2096Example: 2097 2098 make TQM850L_config 2099 make oldconfig 2100 make dep 2101 make uImage 2102 2103The "uImage" build target uses a special tool (in 'tools/mkimage') to 2104encapsulate a compressed Linux kernel image with header information, 2105CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2106 2107* build a standard "vmlinux" kernel image (in ELF binary format): 2108 2109* convert the kernel into a raw binary image: 2110 2111 ${CROSS_COMPILE}-objcopy -O binary \ 2112 -R .note -R .comment \ 2113 -S vmlinux linux.bin 2114 2115* compress the binary image: 2116 2117 gzip -9 linux.bin 2118 2119* package compressed binary image for U-Boot: 2120 2121 mkimage -A ppc -O linux -T kernel -C gzip \ 2122 -a 0 -e 0 -n "Linux Kernel Image" \ 2123 -d linux.bin.gz uImage 2124 2125 2126The "mkimage" tool can also be used to create ramdisk images for use 2127with U-Boot, either separated from the Linux kernel image, or 2128combined into one file. "mkimage" encapsulates the images with a 64 2129byte header containing information about target architecture, 2130operating system, image type, compression method, entry points, time 2131stamp, CRC32 checksums, etc. 2132 2133"mkimage" can be called in two ways: to verify existing images and 2134print the header information, or to build new images. 2135 2136In the first form (with "-l" option) mkimage lists the information 2137contained in the header of an existing U-Boot image; this includes 2138checksum verification: 2139 2140 tools/mkimage -l image 2141 -l ==> list image header information 2142 2143The second form (with "-d" option) is used to build a U-Boot image 2144from a "data file" which is used as image payload: 2145 2146 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2147 -n name -d data_file image 2148 -A ==> set architecture to 'arch' 2149 -O ==> set operating system to 'os' 2150 -T ==> set image type to 'type' 2151 -C ==> set compression type 'comp' 2152 -a ==> set load address to 'addr' (hex) 2153 -e ==> set entry point to 'ep' (hex) 2154 -n ==> set image name to 'name' 2155 -d ==> use image data from 'datafile' 2156 2157Right now, all Linux kernels use the same load address (0x00000000), 2158but the entry point address depends on the kernel version: 2159 2160- 2.2.x kernels have the entry point at 0x0000000C, 2161- 2.3.x and later kernels have the entry point at 0x00000000. 2162 2163So a typical call to build a U-Boot image would read: 2164 2165 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2166 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2167 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2168 > examples/uImage.TQM850L 2169 Image Name: 2.4.4 kernel for TQM850L 2170 Created: Wed Jul 19 02:34:59 2000 2171 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2172 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2173 Load Address: 0x00000000 2174 Entry Point: 0x00000000 2175 2176To verify the contents of the image (or check for corruption): 2177 2178 -> tools/mkimage -l examples/uImage.TQM850L 2179 Image Name: 2.4.4 kernel for TQM850L 2180 Created: Wed Jul 19 02:34:59 2000 2181 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2182 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2183 Load Address: 0x00000000 2184 Entry Point: 0x00000000 2185 2186NOTE: for embedded systems where boot time is critical you can trade 2187speed for memory and install an UNCOMPRESSED image instead: this 2188needs more space in Flash, but boots much faster since it does not 2189need to be uncompressed: 2190 2191 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2192 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2193 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2194 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2195 > examples/uImage.TQM850L-uncompressed 2196 Image Name: 2.4.4 kernel for TQM850L 2197 Created: Wed Jul 19 02:34:59 2000 2198 Image Type: PowerPC Linux Kernel Image (uncompressed) 2199 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2200 Load Address: 0x00000000 2201 Entry Point: 0x00000000 2202 2203 2204Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2205when your kernel is intended to use an initial ramdisk: 2206 2207 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2208 > -A ppc -O linux -T ramdisk -C gzip \ 2209 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2210 Image Name: Simple Ramdisk Image 2211 Created: Wed Jan 12 14:01:50 2000 2212 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2213 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2214 Load Address: 0x00000000 2215 Entry Point: 0x00000000 2216 2217 2218Installing a Linux Image: 2219------------------------- 2220 2221To downloading a U-Boot image over the serial (console) interface, 2222you must convert the image to S-Record format: 2223 2224 objcopy -I binary -O srec examples/image examples/image.srec 2225 2226The 'objcopy' does not understand the information in the U-Boot 2227image header, so the resulting S-Record file will be relative to 2228address 0x00000000. To load it to a given address, you need to 2229specify the target address as 'offset' parameter with the 'loads' 2230command. 2231 2232Example: install the image to address 0x40100000 (which on the 2233TQM8xxL is in the first Flash bank): 2234 2235 => erase 40100000 401FFFFF 2236 2237 .......... done 2238 Erased 8 sectors 2239 2240 => loads 40100000 2241 ## Ready for S-Record download ... 2242 ~>examples/image.srec 2243 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2244 ... 2245 15989 15990 15991 15992 2246 [file transfer complete] 2247 [connected] 2248 ## Start Addr = 0x00000000 2249 2250 2251You can check the success of the download using the 'iminfo' command; 2252this includes a checksum verification so you can be sure no data 2253corruption happened: 2254 2255 => imi 40100000 2256 2257 ## Checking Image at 40100000 ... 2258 Image Name: 2.2.13 for initrd on TQM850L 2259 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2260 Data Size: 335725 Bytes = 327 kB = 0 MB 2261 Load Address: 00000000 2262 Entry Point: 0000000c 2263 Verifying Checksum ... OK 2264 2265 2266 2267Boot Linux: 2268----------- 2269 2270The "bootm" command is used to boot an application that is stored in 2271memory (RAM or Flash). In case of a Linux kernel image, the contents 2272of the "bootargs" environment variable is passed to the kernel as 2273parameters. You can check and modify this variable using the 2274"printenv" and "setenv" commands: 2275 2276 2277 => printenv bootargs 2278 bootargs=root=/dev/ram 2279 2280 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2281 2282 => printenv bootargs 2283 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2284 2285 => bootm 40020000 2286 ## Booting Linux kernel at 40020000 ... 2287 Image Name: 2.2.13 for NFS on TQM850L 2288 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2289 Data Size: 381681 Bytes = 372 kB = 0 MB 2290 Load Address: 00000000 2291 Entry Point: 0000000c 2292 Verifying Checksum ... OK 2293 Uncompressing Kernel Image ... OK 2294 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 2295 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2296 time_init: decrementer frequency = 187500000/60 2297 Calibrating delay loop... 49.77 BogoMIPS 2298 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2299 ... 2300 2301If you want to boot a Linux kernel with initial ram disk, you pass 2302the memory addreses of both the kernel and the initrd image (PPBCOOT 2303format!) to the "bootm" command: 2304 2305 => imi 40100000 40200000 2306 2307 ## Checking Image at 40100000 ... 2308 Image Name: 2.2.13 for initrd on TQM850L 2309 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2310 Data Size: 335725 Bytes = 327 kB = 0 MB 2311 Load Address: 00000000 2312 Entry Point: 0000000c 2313 Verifying Checksum ... OK 2314 2315 ## Checking Image at 40200000 ... 2316 Image Name: Simple Ramdisk Image 2317 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2318 Data Size: 566530 Bytes = 553 kB = 0 MB 2319 Load Address: 00000000 2320 Entry Point: 00000000 2321 Verifying Checksum ... OK 2322 2323 => bootm 40100000 40200000 2324 ## Booting Linux kernel at 40100000 ... 2325 Image Name: 2.2.13 for initrd on TQM850L 2326 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2327 Data Size: 335725 Bytes = 327 kB = 0 MB 2328 Load Address: 00000000 2329 Entry Point: 0000000c 2330 Verifying Checksum ... OK 2331 Uncompressing Kernel Image ... OK 2332 ## Loading RAMDisk Image at 40200000 ... 2333 Image Name: Simple Ramdisk Image 2334 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2335 Data Size: 566530 Bytes = 553 kB = 0 MB 2336 Load Address: 00000000 2337 Entry Point: 00000000 2338 Verifying Checksum ... OK 2339 Loading Ramdisk ... OK 2340 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 2341 Boot arguments: root=/dev/ram 2342 time_init: decrementer frequency = 187500000/60 2343 Calibrating delay loop... 49.77 BogoMIPS 2344 ... 2345 RAMDISK: Compressed image found at block 0 2346 VFS: Mounted root (ext2 filesystem). 2347 2348 bash# 2349 2350More About U-Boot Image Types: 2351------------------------------ 2352 2353U-Boot supports the following image types: 2354 2355 "Standalone Programs" are directly runnable in the environment 2356 provided by U-Boot; it is expected that (if they behave 2357 well) you can continue to work in U-Boot after return from 2358 the Standalone Program. 2359 "OS Kernel Images" are usually images of some Embedded OS which 2360 will take over control completely. Usually these programs 2361 will install their own set of exception handlers, device 2362 drivers, set up the MMU, etc. - this means, that you cannot 2363 expect to re-enter U-Boot except by resetting the CPU. 2364 "RAMDisk Images" are more or less just data blocks, and their 2365 parameters (address, size) are passed to an OS kernel that is 2366 being started. 2367 "Multi-File Images" contain several images, typically an OS 2368 (Linux) kernel image and one or more data images like 2369 RAMDisks. This construct is useful for instance when you want 2370 to boot over the network using BOOTP etc., where the boot 2371 server provides just a single image file, but you want to get 2372 for instance an OS kernel and a RAMDisk image. 2373 2374 "Multi-File Images" start with a list of image sizes, each 2375 image size (in bytes) specified by an "uint32_t" in network 2376 byte order. This list is terminated by an "(uint32_t)0". 2377 Immediately after the terminating 0 follow the images, one by 2378 one, all aligned on "uint32_t" boundaries (size rounded up to 2379 a multiple of 4 bytes). 2380 2381 "Firmware Images" are binary images containing firmware (like 2382 U-Boot or FPGA images) which usually will be programmed to 2383 flash memory. 2384 2385 "Script files" are command sequences that will be executed by 2386 U-Boot's command interpreter; this feature is especially 2387 useful when you configure U-Boot to use a real shell (hush) 2388 as command interpreter. 2389 2390 2391Standalone HOWTO: 2392================= 2393 2394One of the features of U-Boot is that you can dynamically load and 2395run "standalone" applications, which can use some resources of 2396U-Boot like console I/O functions or interrupt services. 2397 2398Two simple examples are included with the sources: 2399 2400"Hello World" Demo: 2401------------------- 2402 2403'examples/hello_world.c' contains a small "Hello World" Demo 2404application; it is automatically compiled when you build U-Boot. 2405It's configured to run at address 0x00040004, so you can play with it 2406like that: 2407 2408 => loads 2409 ## Ready for S-Record download ... 2410 ~>examples/hello_world.srec 2411 1 2 3 4 5 6 7 8 9 10 11 ... 2412 [file transfer complete] 2413 [connected] 2414 ## Start Addr = 0x00040004 2415 2416 => go 40004 Hello World! This is a test. 2417 ## Starting application at 0x00040004 ... 2418 Hello World 2419 argc = 7 2420 argv[0] = "40004" 2421 argv[1] = "Hello" 2422 argv[2] = "World!" 2423 argv[3] = "This" 2424 argv[4] = "is" 2425 argv[5] = "a" 2426 argv[6] = "test." 2427 argv[7] = "<NULL>" 2428 Hit any key to exit ... 2429 2430 ## Application terminated, rc = 0x0 2431 2432Another example, which demonstrates how to register a CPM interrupt 2433handler with the U-Boot code, can be found in 'examples/timer.c'. 2434Here, a CPM timer is set up to generate an interrupt every second. 2435The interrupt service routine is trivial, just printing a '.' 2436character, but this is just a demo program. The application can be 2437controlled by the following keys: 2438 2439 ? - print current values og the CPM Timer registers 2440 b - enable interrupts and start timer 2441 e - stop timer and disable interrupts 2442 q - quit application 2443 2444 => loads 2445 ## Ready for S-Record download ... 2446 ~>examples/timer.srec 2447 1 2 3 4 5 6 7 8 9 10 11 ... 2448 [file transfer complete] 2449 [connected] 2450 ## Start Addr = 0x00040004 2451 2452 => go 40004 2453 ## Starting application at 0x00040004 ... 2454 TIMERS=0xfff00980 2455 Using timer 1 2456 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2457 2458Hit 'b': 2459 [q, b, e, ?] Set interval 1000000 us 2460 Enabling timer 2461Hit '?': 2462 [q, b, e, ?] ........ 2463 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2464Hit '?': 2465 [q, b, e, ?] . 2466 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2467Hit '?': 2468 [q, b, e, ?] . 2469 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2470Hit '?': 2471 [q, b, e, ?] . 2472 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2473Hit 'e': 2474 [q, b, e, ?] ...Stopping timer 2475Hit 'q': 2476 [q, b, e, ?] ## Application terminated, rc = 0x0 2477 2478 2479NetBSD Notes: 2480============= 2481 2482Starting at version 0.9.2, U-Boot supports NetBSD both as host 2483(build U-Boot) and target system (boots NetBSD/mpc8xx). 2484 2485Building requires a cross environment; it is known to work on 2486NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2487need gmake since the Makefiles are not compatible with BSD make). 2488Note that the cross-powerpc package does not install include files; 2489attempting to build U-Boot will fail because <machine/ansi.h> is 2490missing. This file has to be installed and patched manually: 2491 2492 # cd /usr/pkg/cross/powerpc-netbsd/include 2493 # mkdir powerpc 2494 # ln -s powerpc machine 2495 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2496 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2497 2498Native builds *don't* work due to incompatibilities between native 2499and U-Boot include files. 2500 2501Booting assumes that (the first part of) the image booted is a 2502stage-2 loader which in turn loads and then invokes the kernel 2503proper. Loader sources will eventually appear in the NetBSD source 2504tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2505meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2506details. 2507 2508 2509Implementation Internals: 2510========================= 2511 2512The following is not intended to be a complete description of every 2513implementation detail. However, it should help to understand the 2514inner workings of U-Boot and make it easier to port it to custom 2515hardware. 2516 2517 2518Initial Stack, Global Data: 2519--------------------------- 2520 2521The implementation of U-Boot is complicated by the fact that U-Boot 2522starts running out of ROM (flash memory), usually without access to 2523system RAM (because the memory controller is not initialized yet). 2524This means that we don't have writable Data or BSS segments, and BSS 2525is not initialized as zero. To be able to get a C environment working 2526at all, we have to allocate at least a minimal stack. Implementation 2527options for this are defined and restricted by the CPU used: Some CPU 2528models provide on-chip memory (like the IMMR area on MPC8xx and 2529MPC826x processors), on others (parts of) the data cache can be 2530locked as (mis-) used as memory, etc. 2531 2532 Chris Hallinan posted a good summy of these issues to the 2533 u-boot-users mailing list: 2534 2535 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 2536 From: "Chris Hallinan" <clh@net1plus.com> 2537 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 2538 ... 2539 2540 Correct me if I'm wrong, folks, but the way I understand it 2541 is this: Using DCACHE as initial RAM for Stack, etc, does not 2542 require any physical RAM backing up the cache. The cleverness 2543 is that the cache is being used as a temporary supply of 2544 necessary storage before the SDRAM controller is setup. It's 2545 beyond the scope of this list to expain the details, but you 2546 can see how this works by studying the cache architecture and 2547 operation in the architecture and processor-specific manuals. 2548 2549 OCM is On Chip Memory, which I believe the 405GP has 4K. It 2550 is another option for the system designer to use as an 2551 initial stack/ram area prior to SDRAM being available. Either 2552 option should work for you. Using CS 4 should be fine if your 2553 board designers haven't used it for something that would 2554 cause you grief during the initial boot! It is frequently not 2555 used. 2556 2557 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 2558 with your processor/board/system design. The default value 2559 you will find in any recent u-boot distribution in 2560 Walnut405.h should work for you. I'd set it to a value larger 2561 than your SDRAM module. If you have a 64MB SDRAM module, set 2562 it above 400_0000. Just make sure your board has no resources 2563 that are supposed to respond to that address! That code in 2564 start.S has been around a while and should work as is when 2565 you get the config right. 2566 2567 -Chris Hallinan 2568 DS4.COM, Inc. 2569 2570It is essential to remember this, since it has some impact on the C 2571code for the initialization procedures: 2572 2573* Initialized global data (data segment) is read-only. Do not attempt 2574 to write it. 2575 2576* Do not use any unitialized global data (or implicitely initialized 2577 as zero data - BSS segment) at all - this is undefined, initiali- 2578 zation is performed later (when relocationg to RAM). 2579 2580* Stack space is very limited. Avoid big data buffers or things like 2581 that. 2582 2583Having only the stack as writable memory limits means we cannot use 2584normal global data to share information beween the code. But it 2585turned out that the implementation of U-Boot can be greatly 2586simplified by making a global data structure (gd_t) available to all 2587functions. We could pass a pointer to this data as argument to _all_ 2588functions, but this would bloat the code. Instead we use a feature of 2589the GCC compiler (Global Register Variables) to share the data: we 2590place a pointer (gd) to the global data into a register which we 2591reserve for this purpose. 2592 2593When chosing a register for such a purpose we are restricted by the 2594relevant (E)ABI specifications for the current architecture, and by 2595GCC's implementation. 2596 2597For PowerPC, the following registers have specific use: 2598 R1: stack pointer 2599 R2: TOC pointer 2600 R3-R4: parameter passing and return values 2601 R5-R10: parameter passing 2602 R13: small data area pointer 2603 R30: GOT pointer 2604 R31: frame pointer 2605 2606 (U-Boot also uses R14 as internal GOT pointer.) 2607 2608 ==> U-Boot will use R29 to hold a pointer to the global data 2609 2610 Note: on PPC, we could use a static initializer (since the 2611 address of the global data structure is known at compile time), 2612 but it turned out that reserving a register results in somewhat 2613 smaller code - although the code savings are not that big (on 2614 average for all boards 752 bytes for the whole U-Boot image, 2615 624 text + 127 data). 2616 2617On ARM, the following registers are used: 2618 2619 R0: function argument word/integer result 2620 R1-R3: function argument word 2621 R9: GOT pointer 2622 R10: stack limit (used only if stack checking if enabled) 2623 R11: argument (frame) pointer 2624 R12: temporary workspace 2625 R13: stack pointer 2626 R14: link register 2627 R15: program counter 2628 2629 ==> U-Boot will use R8 to hold a pointer to the global data 2630 2631 2632 2633Memory Management: 2634------------------ 2635 2636U-Boot runs in system state and uses physical addresses, i.e. the 2637MMU is not used either for address mapping nor for memory protection. 2638 2639The available memory is mapped to fixed addresses using the memory 2640controller. In this process, a contiguous block is formed for each 2641memory type (Flash, SDRAM, SRAM), even when it consists of several 2642physical memory banks. 2643 2644U-Boot is installed in the first 128 kB of the first Flash bank (on 2645TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2646booting and sizing and initializing DRAM, the code relocates itself 2647to the upper end of DRAM. Immediately below the U-Boot code some 2648memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2649configuration setting]. Below that, a structure with global Board 2650Info data is placed, followed by the stack (growing downward). 2651 2652Additionally, some exception handler code is copied to the low 8 kB 2653of DRAM (0x00000000 ... 0x00001FFF). 2654 2655So a typical memory configuration with 16 MB of DRAM could look like 2656this: 2657 2658 0x0000 0000 Exception Vector code 2659 : 2660 0x0000 1FFF 2661 0x0000 2000 Free for Application Use 2662 : 2663 : 2664 2665 : 2666 : 2667 0x00FB FF20 Monitor Stack (Growing downward) 2668 0x00FB FFAC Board Info Data and permanent copy of global data 2669 0x00FC 0000 Malloc Arena 2670 : 2671 0x00FD FFFF 2672 0x00FE 0000 RAM Copy of Monitor Code 2673 ... eventually: LCD or video framebuffer 2674 ... eventually: pRAM (Protected RAM - unchanged by reset) 2675 0x00FF FFFF [End of RAM] 2676 2677 2678System Initialization: 2679---------------------- 2680 2681In the reset configuration, U-Boot starts at the reset entry point 2682(on most PowerPC systens at address 0x00000100). Because of the reset 2683configuration for CS0# this is a mirror of the onboard Flash memory. 2684To be able to re-map memory U-Boot then jumps to it's link address. 2685To be able to implement the initialization code in C, a (small!) 2686initial stack is set up in the internal Dual Ported RAM (in case CPUs 2687which provide such a feature like MPC8xx or MPC8260), or in a locked 2688part of the data cache. After that, U-Boot initializes the CPU core, 2689the caches and the SIU. 2690 2691Next, all (potentially) available memory banks are mapped using a 2692preliminary mapping. For example, we put them on 512 MB boundaries 2693(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2694on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2695programmed for SDRAM access. Using the temporary configuration, a 2696simple memory test is run that determines the size of the SDRAM 2697banks. 2698 2699When there is more than one SDRAM bank, and the banks are of 2700different size, the larger is mapped first. For equal size, the first 2701bank (CS2#) is mapped first. The first mapping is always for address 27020x00000000, with any additional banks following immediately to create 2703contiguous memory starting from 0. 2704 2705Then, the monitor installs itself at the upper end of the SDRAM area 2706and allocates memory for use by malloc() and for the global Board 2707Info data; also, the exception vector code is copied to the low RAM 2708pages, and the final stack is set up. 2709 2710Only after this relocation will you have a "normal" C environment; 2711until that you are restricted in several ways, mostly because you are 2712running from ROM, and because the code will have to be relocated to a 2713new address in RAM. 2714 2715 2716U-Boot Porting Guide: 2717---------------------- 2718 2719[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2720list, October 2002] 2721 2722 2723int main (int argc, char *argv[]) 2724{ 2725 sighandler_t no_more_time; 2726 2727 signal (SIGALRM, no_more_time); 2728 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2729 2730 if (available_money > available_manpower) { 2731 pay consultant to port U-Boot; 2732 return 0; 2733 } 2734 2735 Download latest U-Boot source; 2736 2737 Subscribe to u-boot-users mailing list; 2738 2739 if (clueless) { 2740 email ("Hi, I am new to U-Boot, how do I get started?"); 2741 } 2742 2743 while (learning) { 2744 Read the README file in the top level directory; 2745 Read http://www.denx.de/re/DPLG.html 2746 Read the source, Luke; 2747 } 2748 2749 if (available_money > toLocalCurrency ($2500)) { 2750 Buy a BDI2000; 2751 } else { 2752 Add a lot of aggravation and time; 2753 } 2754 2755 Create your own board support subdirectory; 2756 2757 Create your own board config file; 2758 2759 while (!running) { 2760 do { 2761 Add / modify source code; 2762 } until (compiles); 2763 Debug; 2764 if (clueless) 2765 email ("Hi, I am having problems..."); 2766 } 2767 Send patch file to Wolfgang; 2768 2769 return 0; 2770} 2771 2772void no_more_time (int sig) 2773{ 2774 hire_a_guru(); 2775} 2776 2777 2778 2779Coding Standards: 2780----------------- 2781 2782All contributions to U-Boot should conform to the Linux kernel 2783coding style; see the file "Documentation/CodingStyle" in your Linux 2784kernel source directory. 2785 2786Please note that U-Boot is implemented in C (and to some small parts 2787in Assembler); no C++ is used, so please do not use C++ style 2788comments (//) in your code. 2789 2790Submissions which do not conform to the standards may be returned 2791with a request to reformat the changes. 2792 2793 2794Submitting Patches: 2795------------------- 2796 2797Since the number of patches for U-Boot is growing, we need to 2798establish some rules. Submissions which do not conform to these rules 2799may be rejected, even when they contain important and valuable stuff. 2800 2801 2802When you send a patch, please include the following information with 2803it: 2804 2805* For bug fixes: a description of the bug and how your patch fixes 2806 this bug. Please try to include a way of demonstrating that the 2807 patch actually fixes something. 2808 2809* For new features: a description of the feature and your 2810 implementation. 2811 2812* A CHANGELOG entry as plaintext (separate from the patch) 2813 2814* For major contributions, your entry to the CREDITS file 2815 2816* When you add support for a new board, don't forget to add this 2817 board to the MAKEALL script, too. 2818 2819* If your patch adds new configuration options, don't forget to 2820 document these in the README file. 2821 2822* The patch itself. If you are accessing the CVS repository use "cvs 2823 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2824 version of diff does not support these options, then get the latest 2825 version of GNU diff. 2826 2827 We accept patches as plain text, MIME attachments or as uuencoded 2828 gzipped text. 2829 2830Notes: 2831 2832* Before sending the patch, run the MAKEALL script on your patched 2833 source tree and make sure that no errors or warnings are reported 2834 for any of the boards. 2835 2836* Keep your modifications to the necessary minimum: A patch 2837 containing several unrelated changes or arbitrary reformats will be 2838 returned with a request to re-formatting / split it. 2839 2840* If you modify existing code, make sure that your new code does not 2841 add to the memory footprint of the code ;-) Small is beautiful! 2842 When adding new features, these should compile conditionally only 2843 (using #ifdef), and the resulting code with the new feature 2844 disabled must not need more memory than the old code without your 2845 modification. 2846