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_DS1337 - use Maxim, Inc. DS1337 RTC 628 629- Timestamp Support: 630 631 When CONFIG_TIMESTAMP is selected, the timestamp 632 (date and time) of an image is printed by image 633 commands like bootm or iminfo. This option is 634 automatically enabled when you select CFG_CMD_DATE . 635 636- Partition Support: 637 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 638 and/or CONFIG_ISO_PARTITION 639 640 If IDE or SCSI support is enabled (CFG_CMD_IDE or 641 CFG_CMD_SCSI) you must configure support for at least 642 one partition type as well. 643 644- IDE Reset method: 645 CONFIG_IDE_RESET_ROUTINE 646 647 Set this to define that instead of a reset Pin, the 648 routine ide_set_reset(int idereset) will be used. 649 650- ATAPI Support: 651 CONFIG_ATAPI 652 653 Set this to enable ATAPI support. 654 655- SCSI Support: 656 At the moment only there is only support for the 657 SYM53C8XX SCSI controller; define 658 CONFIG_SCSI_SYM53C8XX to enable it. 659 660 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 661 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 662 CFG_SCSI_MAX_LUN] can be adjusted to define the 663 maximum numbers of LUNs, SCSI ID's and target 664 devices. 665 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 666 667- NETWORK Support (PCI): 668 CONFIG_EEPRO100 669 Support for Intel 82557/82559/82559ER chips. 670 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 671 write routine for first time initialisation. 672 673 CONFIG_TULIP 674 Support for Digital 2114x chips. 675 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 676 modem chip initialisation (KS8761/QS6611). 677 678 CONFIG_NATSEMI 679 Support for National dp83815 chips. 680 681 CONFIG_NS8382X 682 Support for National dp8382[01] gigabit chips. 683 684- USB Support: 685 At the moment only the UHCI host controller is 686 supported (PIP405, MIP405); define 687 CONFIG_USB_UHCI to enable it. 688 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 689 end define CONFIG_USB_STORAGE to enable the USB 690 storage devices. 691 Note: 692 Supported are USB Keyboards and USB Floppy drives 693 (TEAC FD-05PUB). 694 695- Keyboard Support: 696 CONFIG_ISA_KEYBOARD 697 698 Define this to enable standard (PC-Style) keyboard 699 support 700 701 CONFIG_I8042_KBD 702 Standard PC keyboard driver with US (is default) and 703 GERMAN key layout (switch via environment 'keymap=de') support. 704 Export function i8042_kbd_init, i8042_tstc and i8042_getc 705 for cfb_console. Supports cursor blinking. 706 707- Video support: 708 CONFIG_VIDEO 709 710 Define this to enable video support (for output to 711 video). 712 713 CONFIG_VIDEO_CT69000 714 715 Enable Chips & Technologies 69000 Video chip 716 717 CONFIG_VIDEO_SMI_LYNXEM 718 Enable Silicon Motion SMI 712/710/810 Video chip 719 Videomode are selected via environment 'videomode' with 720 standard LiLo mode numbers. 721 Following modes are supported (* is default): 722 723 800x600 1024x768 1280x1024 724 256 (8bit) 303* 305 307 725 65536 (16bit) 314 317 31a 726 16,7 Mill (24bit) 315 318 31b 727 (i.e. setenv videomode 317; saveenv; reset;) 728 729 CONFIG_VIDEO_SED13806 730 Enable Epson SED13806 driver. This driver supports 8bpp 731 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 732 or CONFIG_VIDEO_SED13806_16BPP 733 734 735- LCD Support: CONFIG_LCD 736 737 Define this to enable LCD support (for output to LCD 738 display); also select one of the supported displays 739 by defining one of these: 740 741 CONFIG_NEC_NL6648AC33: 742 743 NEC NL6648AC33-18. Active, color, single scan. 744 745 CONFIG_NEC_NL6648BC20 746 747 NEC NL6648BC20-08. 6.5", 640x480. 748 Active, color, single scan. 749 750 CONFIG_SHARP_16x9 751 752 Sharp 320x240. Active, color, single scan. 753 It isn't 16x9, and I am not sure what it is. 754 755 CONFIG_SHARP_LQ64D341 756 757 Sharp LQ64D341 display, 640x480. 758 Active, color, single scan. 759 760 CONFIG_HLD1045 761 762 HLD1045 display, 640x480. 763 Active, color, single scan. 764 765 CONFIG_OPTREX_BW 766 767 Optrex CBL50840-2 NF-FW 99 22 M5 768 or 769 Hitachi LMG6912RPFC-00T 770 or 771 Hitachi SP14Q002 772 773 320x240. Black & white. 774 775 Normally display is black on white background; define 776 CFG_WHITE_ON_BLACK to get it inverted. 777 778- Ethernet address: 779 CONFIG_ETHADDR 780 CONFIG_ETH2ADDR 781 CONFIG_ETH3ADDR 782 783 Define a default value for ethernet address to use 784 for the respective ethernet interface, in case this 785 is not determined automatically. 786 787- IP address: 788 CONFIG_IPADDR 789 790 Define a default value for the IP address to use for 791 the default ethernet interface, in case this is not 792 determined through e.g. bootp. 793 794- Server IP address: 795 CONFIG_SERVERIP 796 797 Defines a default value for theIP address of a TFTP 798 server to contact when using the "tftboot" command. 799 800- BOOTP Recovery Mode: 801 CONFIG_BOOTP_RANDOM_DELAY 802 803 If you have many targets in a network that try to 804 boot using BOOTP, you may want to avoid that all 805 systems send out BOOTP requests at precisely the same 806 moment (which would happen for instance at recovery 807 from a power failure, when all systems will try to 808 boot, thus flooding the BOOTP server. Defining 809 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 810 inserted before sending out BOOTP requests. The 811 following delays are insterted then: 812 813 1st BOOTP request: delay 0 ... 1 sec 814 2nd BOOTP request: delay 0 ... 2 sec 815 3rd BOOTP request: delay 0 ... 4 sec 816 4th and following 817 BOOTP requests: delay 0 ... 8 sec 818 819- Status LED: CONFIG_STATUS_LED 820 821 Several configurations allow to display the current 822 status using a LED. For instance, the LED will blink 823 fast while running U-Boot code, stop blinking as 824 soon as a reply to a BOOTP request was received, and 825 start blinking slow once the Linux kernel is running 826 (supported by a status LED driver in the Linux 827 kernel). Defining CONFIG_STATUS_LED enables this 828 feature in U-Boot. 829 830- CAN Support: CONFIG_CAN_DRIVER 831 832 Defining CONFIG_CAN_DRIVER enables CAN driver support 833 on those systems that support this (optional) 834 feature, like the TQM8xxL modules. 835 836- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 837 838 Enables I2C serial bus commands. If this is selected, 839 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 840 to include the appropriate I2C driver. 841 842 See also: common/cmd_i2c.c for a description of the 843 command line interface. 844 845 846 CONFIG_HARD_I2C 847 848 Selects the CPM hardware driver for I2C. 849 850 CONFIG_SOFT_I2C 851 852 Use software (aka bit-banging) driver instead of CPM 853 or similar hardware support for I2C. This is configured 854 via the following defines. 855 856 I2C_INIT 857 858 (Optional). Any commands necessary to enable I2C 859 controller or configure ports. 860 861 I2C_PORT 862 863 (Only for MPC8260 CPU). The I/O port to use (the code 864 assumes both bits are on the same port). Valid values 865 are 0..3 for ports A..D. 866 867 I2C_ACTIVE 868 869 The code necessary to make the I2C data line active 870 (driven). If the data line is open collector, this 871 define can be null. 872 873 I2C_TRISTATE 874 875 The code necessary to make the I2C data line tri-stated 876 (inactive). If the data line is open collector, this 877 define can be null. 878 879 I2C_READ 880 881 Code that returns TRUE if the I2C data line is high, 882 FALSE if it is low. 883 884 I2C_SDA(bit) 885 886 If <bit> is TRUE, sets the I2C data line high. If it 887 is FALSE, it clears it (low). 888 889 I2C_SCL(bit) 890 891 If <bit> is TRUE, sets the I2C clock line high. If it 892 is FALSE, it clears it (low). 893 894 I2C_DELAY 895 896 This delay is invoked four times per clock cycle so this 897 controls the rate of data transfer. The data rate thus 898 is 1 / (I2C_DELAY * 4). 899 900 CFG_I2C_INIT_BOARD 901 902 When a board is reset during an i2c bus transfer 903 chips might think that the current transfer is still 904 in progress. On some boards it is possible to access 905 the i2c SCLK line directly, either by using the 906 processor pin as a GPIO or by having a second pin 907 connected to the bus. If this option is defined a 908 custom i2c_init_board() routine in boards/xxx/board.c 909 is run early in the boot sequence. 910 911- SPI Support: CONFIG_SPI 912 913 Enables SPI driver (so far only tested with 914 SPI EEPROM, also an instance works with Crystal A/D and 915 D/As on the SACSng board) 916 917 CONFIG_SPI_X 918 919 Enables extended (16-bit) SPI EEPROM addressing. 920 (symmetrical to CONFIG_I2C_X) 921 922 CONFIG_SOFT_SPI 923 924 Enables a software (bit-bang) SPI driver rather than 925 using hardware support. This is a general purpose 926 driver that only requires three general I/O port pins 927 (two outputs, one input) to function. If this is 928 defined, the board configuration must define several 929 SPI configuration items (port pins to use, etc). For 930 an example, see include/configs/sacsng.h. 931 932- FPGA Support: CONFIG_FPGA_COUNT 933 934 Specify the number of FPGA devices to support. 935 936 CONFIG_FPGA 937 938 Used to specify the types of FPGA devices. For 939 example, 940 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 941 942 CFG_FPGA_PROG_FEEDBACK 943 944 Enable printing of hash marks during FPGA 945 configuration. 946 947 CFG_FPGA_CHECK_BUSY 948 949 Enable checks on FPGA configuration interface busy 950 status by the configuration function. This option 951 will require a board or device specific function to 952 be written. 953 954 CONFIG_FPGA_DELAY 955 956 If defined, a function that provides delays in the 957 FPGA configuration driver. 958 959 CFG_FPGA_CHECK_CTRLC 960 961 Allow Control-C to interrupt FPGA configuration 962 963 CFG_FPGA_CHECK_ERROR 964 965 Check for configuration errors during FPGA bitfile 966 loading. For example, abort during Virtex II 967 configuration if the INIT_B line goes low (which 968 indicated a CRC error). 969 970 CFG_FPGA_WAIT_INIT 971 972 Maximum time to wait for the INIT_B line to deassert 973 after PROB_B has been deasserted during a Virtex II 974 FPGA configuration sequence. The default time is 500 mS. 975 976 CFG_FPGA_WAIT_BUSY 977 978 Maximum time to wait for BUSY to deassert during 979 Virtex II FPGA configuration. The default is 5 mS. 980 981 CFG_FPGA_WAIT_CONFIG 982 983 Time to wait after FPGA configuration. The default is 984 200 mS. 985 986- FPGA Support: CONFIG_FPGA_COUNT 987 988 Specify the number of FPGA devices to support. 989 990 CONFIG_FPGA 991 992 Used to specify the types of FPGA devices. For example, 993 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 994 995 CFG_FPGA_PROG_FEEDBACK 996 997 Enable printing of hash marks during FPGA configuration. 998 999 CFG_FPGA_CHECK_BUSY 1000 1001 Enable checks on FPGA configuration interface busy 1002 status by the configuration function. This option 1003 will require a board or device specific function to 1004 be written. 1005 1006 CONFIG_FPGA_DELAY 1007 1008 If defined, a function that provides delays in the FPGA 1009 configuration driver. 1010 1011 CFG_FPGA_CHECK_CTRLC 1012 Allow Control-C to interrupt FPGA configuration 1013 1014 CFG_FPGA_CHECK_ERROR 1015 1016 Check for configuration errors during FPGA bitfile 1017 loading. For example, abort during Virtex II 1018 configuration if the INIT_B line goes low (which 1019 indicated a CRC error). 1020 1021 CFG_FPGA_WAIT_INIT 1022 1023 Maximum time to wait for the INIT_B line to deassert 1024 after PROB_B has been deasserted during a Virtex II 1025 FPGA configuration sequence. The default time is 500 1026 mS. 1027 1028 CFG_FPGA_WAIT_BUSY 1029 1030 Maximum time to wait for BUSY to deassert during 1031 Virtex II FPGA configuration. The default is 5 mS. 1032 1033 CFG_FPGA_WAIT_CONFIG 1034 1035 Time to wait after FPGA configuration. The default is 1036 200 mS. 1037 1038- Configuration Management: 1039 CONFIG_IDENT_STRING 1040 1041 If defined, this string will be added to the U-Boot 1042 version information (U_BOOT_VERSION) 1043 1044- Vendor Parameter Protection: 1045 1046 U-Boot considers the values of the environment 1047 variables "serial#" (Board Serial Number) and 1048 "ethaddr" (Ethernet Address) to bb parameters that 1049 are set once by the board vendor / manufacturer, and 1050 protects these variables from casual modification by 1051 the user. Once set, these variables are read-only, 1052 and write or delete attempts are rejected. You can 1053 change this behviour: 1054 1055 If CONFIG_ENV_OVERWRITE is #defined in your config 1056 file, the write protection for vendor parameters is 1057 completely disabled. Anybody can change or delete 1058 these parameters. 1059 1060 Alternatively, if you #define _both_ CONFIG_ETHADDR 1061 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1062 ethernet address is installed in the environment, 1063 which can be changed exactly ONCE by the user. [The 1064 serial# is unaffected by this, i. e. it remains 1065 read-only.] 1066 1067- Protected RAM: 1068 CONFIG_PRAM 1069 1070 Define this variable to enable the reservation of 1071 "protected RAM", i. e. RAM which is not overwritten 1072 by U-Boot. Define CONFIG_PRAM to hold the number of 1073 kB you want to reserve for pRAM. You can overwrite 1074 this default value by defining an environment 1075 variable "pram" to the number of kB you want to 1076 reserve. Note that the board info structure will 1077 still show the full amount of RAM. If pRAM is 1078 reserved, a new environment variable "mem" will 1079 automatically be defined to hold the amount of 1080 remaining RAM in a form that can be passed as boot 1081 argument to Linux, for instance like that: 1082 1083 setenv bootargs ... mem=\$(mem) 1084 saveenv 1085 1086 This way you can tell Linux not to use this memory, 1087 either, which results in a memory region that will 1088 not be affected by reboots. 1089 1090 *WARNING* If your board configuration uses automatic 1091 detection of the RAM size, you must make sure that 1092 this memory test is non-destructive. So far, the 1093 following board configurations are known to be 1094 "pRAM-clean": 1095 1096 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1097 HERMES, IP860, RPXlite, LWMON, LANTEC, 1098 PCU_E, FLAGADM, TQM8260 1099 1100- Error Recovery: 1101 CONFIG_PANIC_HANG 1102 1103 Define this variable to stop the system in case of a 1104 fatal error, so that you have to reset it manually. 1105 This is probably NOT a good idea for an embedded 1106 system where you want to system to reboot 1107 automatically as fast as possible, but it may be 1108 useful during development since you can try to debug 1109 the conditions that lead to the situation. 1110 1111 CONFIG_NET_RETRY_COUNT 1112 1113 This variable defines the number of retries for 1114 network operations like ARP, RARP, TFTP, or BOOTP 1115 before giving up the operation. If not defined, a 1116 default value of 5 is used. 1117 1118- Command Interpreter: 1119 CFG_HUSH_PARSER 1120 1121 Define this variable to enable the "hush" shell (from 1122 Busybox) as command line interpreter, thus enabling 1123 powerful command line syntax like 1124 if...then...else...fi conditionals or `&&' and '||' 1125 constructs ("shell scripts"). 1126 1127 If undefined, you get the old, much simpler behaviour 1128 with a somewhat smaller memory footprint. 1129 1130 1131 CFG_PROMPT_HUSH_PS2 1132 1133 This defines the secondary prompt string, which is 1134 printed when the command interpreter needs more input 1135 to complete a command. Usually "> ". 1136 1137 Note: 1138 1139 In the current implementation, the local variables 1140 space and global environment variables space are 1141 separated. Local variables are those you define by 1142 simply typing like `name=value'. To access a local 1143 variable later on, you have write `$name' or 1144 `${name}'; variable directly by typing say `$name' at 1145 the command prompt. 1146 1147 Global environment variables are those you use 1148 setenv/printenv to work with. To run a command stored 1149 in such a variable, you need to use the run command, 1150 and you must not use the '$' sign to access them. 1151 1152 To store commands and special characters in a 1153 variable, please use double quotation marks 1154 surrounding the whole text of the variable, instead 1155 of the backslashes before semicolons and special 1156 symbols. 1157 1158- Default Environment 1159 CONFIG_EXTRA_ENV_SETTINGS 1160 1161 Define this to contain any number of null terminated 1162 strings (variable = value pairs) that will be part of 1163 the default enviroment compiled into the boot image. 1164 1165 For example, place something like this in your 1166 board's config file: 1167 1168 #define CONFIG_EXTRA_ENV_SETTINGS \ 1169 "myvar1=value1\0" \ 1170 "myvar2=value2\0" 1171 1172 Warning: This method is based on knowledge about the 1173 internal format how the environment is stored by the 1174 U-Boot code. This is NOT an official, exported 1175 interface! Although it is unlikely that this format 1176 will change soon, but there is no guarantee either. 1177 You better know what you are doing here. 1178 1179 Note: overly (ab)use of the default environment is 1180 discouraged. Make sure to check other ways to preset 1181 the environment like the autoscript function or the 1182 boot command first. 1183 1184- Show boot progress 1185 CONFIG_SHOW_BOOT_PROGRESS 1186 1187 Defining this option allows to add some board- 1188 specific code (calling a user-provided function 1189 "show_boot_progress(int)") that enables you to show 1190 the system's boot progress on some display (for 1191 example, some LED's) on your board. At the moment, 1192 the following checkpoints are implemented: 1193 1194 Arg Where When 1195 1 common/cmd_bootm.c before attempting to boot an image 1196 -1 common/cmd_bootm.c Image header has bad magic number 1197 2 common/cmd_bootm.c Image header has correct magic number 1198 -2 common/cmd_bootm.c Image header has bad checksum 1199 3 common/cmd_bootm.c Image header has correct checksum 1200 -3 common/cmd_bootm.c Image data has bad checksum 1201 4 common/cmd_bootm.c Image data has correct checksum 1202 -4 common/cmd_bootm.c Image is for unsupported architecture 1203 5 common/cmd_bootm.c Architecture check OK 1204 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1205 6 common/cmd_bootm.c Image Type check OK 1206 -6 common/cmd_bootm.c gunzip uncompression error 1207 -7 common/cmd_bootm.c Unimplemented compression type 1208 7 common/cmd_bootm.c Uncompression OK 1209 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1210 8 common/cmd_bootm.c Image Type check OK 1211 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1212 9 common/cmd_bootm.c Start initial ramdisk verification 1213 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1214 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1215 10 common/cmd_bootm.c Ramdisk header is OK 1216 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1217 11 common/cmd_bootm.c Ramdisk data has correct checksum 1218 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1219 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1220 13 common/cmd_bootm.c Start multifile image verification 1221 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1222 15 common/cmd_bootm.c All preparation done, transferring control to OS 1223 1224 -1 common/cmd_doc.c Bad usage of "doc" command 1225 -1 common/cmd_doc.c No boot device 1226 -1 common/cmd_doc.c Unknown Chip ID on boot device 1227 -1 common/cmd_doc.c Read Error on boot device 1228 -1 common/cmd_doc.c Image header has bad magic number 1229 1230 -1 common/cmd_ide.c Bad usage of "ide" command 1231 -1 common/cmd_ide.c No boot device 1232 -1 common/cmd_ide.c Unknown boot device 1233 -1 common/cmd_ide.c Unknown partition table 1234 -1 common/cmd_ide.c Invalid partition type 1235 -1 common/cmd_ide.c Read Error on boot device 1236 -1 common/cmd_ide.c Image header has bad magic number 1237 1238 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1239 1240 1241Modem Support: 1242-------------- 1243 1244[so far only for SMDK2400 board] 1245 1246- Modem support endable: 1247 CONFIG_MODEM_SUPPORT 1248 1249- RTS/CTS Flow control enable: 1250 CONFIG_HWFLOW 1251 1252- Modem debug support: 1253 CONFIG_MODEM_SUPPORT_DEBUG 1254 1255 Enables debugging stuff (char screen[1024], dbg()) 1256 for modem support. Useful only with BDI2000. 1257 1258- General: 1259 1260 In the target system modem support is enabled when a 1261 specific key (key combination) is pressed during 1262 power-on. Otherwise U-Boot will boot normally 1263 (autoboot). The key_pressed() fuction is called from 1264 board_init(). Currently key_pressed() is a dummy 1265 function, returning 1 and thus enabling modem 1266 initialization. 1267 1268 If there are no modem init strings in the 1269 environment, U-Boot proceed to autoboot; the 1270 previous output (banner, info printfs) will be 1271 supressed, though. 1272 1273 See also: doc/README.Modem 1274 1275 1276 1277 1278Configuration Settings: 1279----------------------- 1280 1281- CFG_LONGHELP: Defined when you want long help messages included; 1282 undefine this when you're short of memory. 1283 1284- CFG_PROMPT: This is what U-Boot prints on the console to 1285 prompt for user input. 1286 1287- CFG_CBSIZE: Buffer size for input from the Console 1288 1289- CFG_PBSIZE: Buffer size for Console output 1290 1291- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1292 1293- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1294 the application (usually a Linux kernel) when it is 1295 booted 1296 1297- CFG_BAUDRATE_TABLE: 1298 List of legal baudrate settings for this board. 1299 1300- CFG_CONSOLE_INFO_QUIET 1301 Suppress display of console information at boot. 1302 1303- CFG_CONSOLE_IS_IN_ENV 1304 If the board specific function 1305 extern int overwrite_console (void); 1306 returns 1, the stdin, stderr and stdout are switched to the 1307 serial port, else the settings in the environment are used. 1308 1309- CFG_CONSOLE_OVERWRITE_ROUTINE 1310 Enable the call to overwrite_console(). 1311 1312- CFG_CONSOLE_ENV_OVERWRITE 1313 Enable overwrite of previous console environment settings. 1314 1315- CFG_MEMTEST_START, CFG_MEMTEST_END: 1316 Begin and End addresses of the area used by the 1317 simple memory test. 1318 1319- CFG_ALT_MEMTEST: 1320 Enable an alternate, more extensive memory test. 1321 1322- CFG_TFTP_LOADADDR: 1323 Default load address for network file downloads 1324 1325- CFG_LOADS_BAUD_CHANGE: 1326 Enable temporary baudrate change while serial download 1327 1328- CFG_SDRAM_BASE: 1329 Physical start address of SDRAM. _Must_ be 0 here. 1330 1331- CFG_MBIO_BASE: 1332 Physical start address of Motherboard I/O (if using a 1333 Cogent motherboard) 1334 1335- CFG_FLASH_BASE: 1336 Physical start address of Flash memory. 1337 1338- CFG_MONITOR_BASE: 1339 Physical start address of boot monitor code (set by 1340 make config files to be same as the text base address 1341 (TEXT_BASE) used when linking) - same as 1342 CFG_FLASH_BASE when booting from flash. 1343 1344- CFG_MONITOR_LEN: 1345 Size of memory reserved for monitor code 1346 1347- CFG_MALLOC_LEN: 1348 Size of DRAM reserved for malloc() use. 1349 1350- CFG_BOOTMAPSZ: 1351 Maximum size of memory mapped by the startup code of 1352 the Linux kernel; all data that must be processed by 1353 the Linux kernel (bd_info, boot arguments, eventually 1354 initrd image) must be put below this limit. 1355 1356- CFG_MAX_FLASH_BANKS: 1357 Max number of Flash memory banks 1358 1359- CFG_MAX_FLASH_SECT: 1360 Max number of sectors on a Flash chip 1361 1362- CFG_FLASH_ERASE_TOUT: 1363 Timeout for Flash erase operations (in ms) 1364 1365- CFG_FLASH_WRITE_TOUT: 1366 Timeout for Flash write operations (in ms) 1367 1368- CFG_DIRECT_FLASH_TFTP: 1369 1370 Enable TFTP transfers directly to flash memory; 1371 without this option such a download has to be 1372 performed in two steps: (1) download to RAM, and (2) 1373 copy from RAM to flash. 1374 1375 The two-step approach is usually more reliable, since 1376 you can check if the download worked before you erase 1377 the flash, but in some situations (when sytem RAM is 1378 too limited to allow for a tempory copy of the 1379 downloaded image) this option may be very useful. 1380 1381- CFG_FLASH_CFI: 1382 Define if the flash driver uses extra elements in the 1383 common flash structure for storing flash geometry 1384 1385The following definitions that deal with the placement and management 1386of environment data (variable area); in general, we support the 1387following configurations: 1388 1389- CFG_ENV_IS_IN_FLASH: 1390 1391 Define this if the environment is in flash memory. 1392 1393 a) The environment occupies one whole flash sector, which is 1394 "embedded" in the text segment with the U-Boot code. This 1395 happens usually with "bottom boot sector" or "top boot 1396 sector" type flash chips, which have several smaller 1397 sectors at the start or the end. For instance, such a 1398 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1399 such a case you would place the environment in one of the 1400 4 kB sectors - with U-Boot code before and after it. With 1401 "top boot sector" type flash chips, you would put the 1402 environment in one of the last sectors, leaving a gap 1403 between U-Boot and the environment. 1404 1405 - CFG_ENV_OFFSET: 1406 1407 Offset of environment data (variable area) to the 1408 beginning of flash memory; for instance, with bottom boot 1409 type flash chips the second sector can be used: the offset 1410 for this sector is given here. 1411 1412 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1413 1414 - CFG_ENV_ADDR: 1415 1416 This is just another way to specify the start address of 1417 the flash sector containing the environment (instead of 1418 CFG_ENV_OFFSET). 1419 1420 - CFG_ENV_SECT_SIZE: 1421 1422 Size of the sector containing the environment. 1423 1424 1425 b) Sometimes flash chips have few, equal sized, BIG sectors. 1426 In such a case you don't want to spend a whole sector for 1427 the environment. 1428 1429 - CFG_ENV_SIZE: 1430 1431 If you use this in combination with CFG_ENV_IS_IN_FLASH 1432 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1433 of this flash sector for the environment. This saves 1434 memory for the RAM copy of the environment. 1435 1436 It may also save flash memory if you decide to use this 1437 when your environment is "embedded" within U-Boot code, 1438 since then the remainder of the flash sector could be used 1439 for U-Boot code. It should be pointed out that this is 1440 STRONGLY DISCOURAGED from a robustness point of view: 1441 updating the environment in flash makes it always 1442 necessary to erase the WHOLE sector. If something goes 1443 wrong before the contents has been restored from a copy in 1444 RAM, your target system will be dead. 1445 1446 - CFG_ENV_ADDR_REDUND 1447 CFG_ENV_SIZE_REDUND 1448 1449 These settings describe a second storage area used to hold 1450 a redundand copy of the environment data, so that there is 1451 a valid backup copy in case there is a power failur during 1452 a "saveenv" operation. 1453 1454BE CAREFUL! Any changes to the flash layout, and some changes to the 1455source code will make it necessary to adapt <board>/u-boot.lds* 1456accordingly! 1457 1458 1459- CFG_ENV_IS_IN_NVRAM: 1460 1461 Define this if you have some non-volatile memory device 1462 (NVRAM, battery buffered SRAM) which you want to use for the 1463 environment. 1464 1465 - CFG_ENV_ADDR: 1466 - CFG_ENV_SIZE: 1467 1468 These two #defines are used to determin the memory area you 1469 want to use for environment. It is assumed that this memory 1470 can just be read and written to, without any special 1471 provision. 1472 1473BE CAREFUL! The first access to the environment happens quite early 1474in U-Boot initalization (when we try to get the setting of for the 1475console baudrate). You *MUST* have mappend your NVRAM area then, or 1476U-Boot will hang. 1477 1478Please note that even with NVRAM we still use a copy of the 1479environment in RAM: we could work on NVRAM directly, but we want to 1480keep settings there always unmodified except somebody uses "saveenv" 1481to save the current settings. 1482 1483 1484- CFG_ENV_IS_IN_EEPROM: 1485 1486 Use this if you have an EEPROM or similar serial access 1487 device and a driver for it. 1488 1489 - CFG_ENV_OFFSET: 1490 - CFG_ENV_SIZE: 1491 1492 These two #defines specify the offset and size of the 1493 environment area within the total memory of your EEPROM. 1494 1495 - CFG_I2C_EEPROM_ADDR: 1496 If defined, specified the chip address of the EEPROM device. 1497 The default address is zero. 1498 1499 - CFG_EEPROM_PAGE_WRITE_BITS: 1500 If defined, the number of bits used to address bytes in a 1501 single page in the EEPROM device. A 64 byte page, for example 1502 would require six bits. 1503 1504 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1505 If defined, the number of milliseconds to delay between 1506 page writes. The default is zero milliseconds. 1507 1508 - CFG_I2C_EEPROM_ADDR_LEN: 1509 The length in bytes of the EEPROM memory array address. Note 1510 that this is NOT the chip address length! 1511 1512 - CFG_EEPROM_SIZE: 1513 The size in bytes of the EEPROM device. 1514 1515 1516- CFG_SPI_INIT_OFFSET 1517 1518 Defines offset to the initial SPI buffer area in DPRAM. The 1519 area is used at an early stage (ROM part) if the environment 1520 is configured to reside in the SPI EEPROM: We need a 520 byte 1521 scratch DPRAM area. It is used between the two initialization 1522 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1523 to be a good choice since it makes it far enough from the 1524 start of the data area as well as from the stack pointer. 1525 1526Please note that the environment is read-only as long as the monitor 1527has been relocated to RAM and a RAM copy of the environment has been 1528created; also, when using EEPROM you will have to use getenv_r() 1529until then to read environment variables. 1530 1531The environment is now protected by a CRC32 checksum. Before the 1532monitor is relocated into RAM, as a result of a bad CRC you will be 1533working with the compiled-in default environment - *silently*!!! 1534[This is necessary, because the first environment variable we need is 1535the "baudrate" setting for the console - if we have a bad CRC, we 1536don't have any device yet where we could complain.] 1537 1538Note: once the monitor has been relocated, then it will complain if 1539the default environment is used; a new CRC is computed as soon as you 1540use the "setenv" command to modify / delete / add any environment 1541variable [even when you try to delete a non-existing variable!]. 1542 1543Note2: you must edit your u-boot.lds file to reflect this 1544configuration. 1545 1546 1547Low Level (hardware related) configuration options: 1548 1549- CFG_CACHELINE_SIZE: 1550 Cache Line Size of the CPU. 1551 1552- CFG_DEFAULT_IMMR: 1553 Default address of the IMMR after system reset. 1554 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1555 to be able to adjust the position of the IMMR 1556 register after a reset. 1557 1558- Floppy Disk Support: 1559 CFG_FDC_DRIVE_NUMBER 1560 1561 the default drive number (default value 0) 1562 1563 CFG_ISA_IO_STRIDE 1564 1565 defines the spacing between fdc chipset registers 1566 (default value 1) 1567 1568 CFG_ISA_IO_OFFSET 1569 1570 defines the offset of register from address. It 1571 depends on which part of the data bus is connected to 1572 the fdc chipset. (default value 0) 1573 1574 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1575 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1576 default value. 1577 1578 if CFG_FDC_HW_INIT is defined, then the function 1579 fdc_hw_init() is called at the beginning of the FDC 1580 setup. fdc_hw_init() must be provided by the board 1581 source code. It is used to make hardware dependant 1582 initializations. 1583 1584- CFG_IMMR: Physical address of the Internal Memory Mapped 1585 Register; DO NOT CHANGE! (11-4) 1586 [MPC8xx systems only] 1587 1588- CFG_INIT_RAM_ADDR: 1589 1590 Start address of memory area tha can be used for 1591 initial data and stack; please note that this must be 1592 writable memory that is working WITHOUT special 1593 initialization, i. e. you CANNOT use normal RAM which 1594 will become available only after programming the 1595 memory controller and running certain initialization 1596 sequences. 1597 1598 U-Boot uses the following memory types: 1599 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1600 - MPC824X: data cache 1601 - PPC4xx: data cache 1602 1603- CFG_INIT_DATA_OFFSET: 1604 1605 Offset of the initial data structure in the memory 1606 area defined by CFG_INIT_RAM_ADDR. Usually 1607 CFG_INIT_DATA_OFFSET is chosen such that the initial 1608 data is located at the end of the available space 1609 (sometimes written as (CFG_INIT_RAM_END - 1610 CFG_INIT_DATA_SIZE), and the initial stack is just 1611 below that area (growing from (CFG_INIT_RAM_ADDR + 1612 CFG_INIT_DATA_OFFSET) downward. 1613 1614 Note: 1615 On the MPC824X (or other systems that use the data 1616 cache for initial memory) the address chosen for 1617 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1618 point to an otherwise UNUSED address space between 1619 the top of RAM and the start of the PCI space. 1620 1621- CFG_SIUMCR: SIU Module Configuration (11-6) 1622 1623- CFG_SYPCR: System Protection Control (11-9) 1624 1625- CFG_TBSCR: Time Base Status and Control (11-26) 1626 1627- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1628 1629- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1630 1631- CFG_SCCR: System Clock and reset Control Register (15-27) 1632 1633- CFG_OR_TIMING_SDRAM: 1634 SDRAM timing 1635 1636- CFG_MAMR_PTA: 1637 periodic timer for refresh 1638 1639- CFG_DER: Debug Event Register (37-47) 1640 1641- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1642 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1643 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1644 CFG_BR1_PRELIM: 1645 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1646 1647- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1648 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1649 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1650 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1651 1652- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1653 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1654 Machine Mode Register and Memory Periodic Timer 1655 Prescaler definitions (SDRAM timing) 1656 1657- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1658 enable I2C microcode relocation patch (MPC8xx); 1659 define relocation offset in DPRAM [DSP2] 1660 1661- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1662 enable SPI microcode relocation patch (MPC8xx); 1663 define relocation offset in DPRAM [SCC4] 1664 1665- CFG_USE_OSCCLK: 1666 Use OSCM clock mode on MBX8xx board. Be careful, 1667 wrong setting might damage your board. Read 1668 doc/README.MBX before setting this variable! 1669 1670- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1671 Offset of the bootmode word in DPRAM used by post 1672 (Power On Self Tests). This definition overrides 1673 #define'd default value in commproc.h resp. 1674 cpm_8260.h. 1675 1676Building the Software: 1677====================== 1678 1679Building U-Boot has been tested in native PPC environments (on a 1680PowerBook G3 running LinuxPPC 2000) and in cross environments 1681(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1682NetBSD 1.5 on x86). 1683 1684If you are not using a native PPC environment, it is assumed that you 1685have the GNU cross compiling tools available in your path and named 1686with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1687you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1688the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1689change it to: 1690 1691 CROSS_COMPILE = ppc_4xx- 1692 1693 1694U-Boot is intended to be simple to build. After installing the 1695sources you must configure U-Boot for one specific board type. This 1696is done by typing: 1697 1698 make NAME_config 1699 1700where "NAME_config" is the name of one of the existing 1701configurations; the following names are supported: 1702 1703 ADCIOP_config GTH_config TQM850L_config 1704 ADS860_config IP860_config TQM855L_config 1705 AR405_config IVML24_config TQM860L_config 1706 CANBT_config IVMS8_config WALNUT405_config 1707 CPCI405_config LANTEC_config cogent_common_config 1708 CPCIISER4_config MBX_config cogent_mpc8260_config 1709 CU824_config MBX860T_config cogent_mpc8xx_config 1710 ESTEEM192E_config RPXlite_config hermes_config 1711 ETX094_config RPXsuper_config hymod_config 1712 FADS823_config SM850_config lwmon_config 1713 FADS850SAR_config SPD823TS_config pcu_e_config 1714 FADS860T_config SXNI855T_config rsdproto_config 1715 FPS850L_config Sandpoint8240_config sbc8260_config 1716 GENIETV_config TQM823L_config PIP405_config 1717 GEN860T_config EBONY_config FPS860L_config 1718 1719Note: for some board special configuration names may exist; check if 1720 additional information is available from the board vendor; for 1721 instance, the TQM8xxL systems run normally at 50 MHz and use a 1722 SCC for 10baseT ethernet; there are also systems with 80 MHz 1723 CPU clock, and an optional Fast Ethernet module is available 1724 for CPU's with FEC. You can select such additional "features" 1725 when chosing the configuration, i. e. 1726 1727 make TQM860L_config 1728 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1729 1730 make TQM860L_FEC_config 1731 - will configure for a TQM860L at 50MHz with FEC for ethernet 1732 1733 make TQM860L_80MHz_config 1734 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1735 interface 1736 1737 make TQM860L_FEC_80MHz_config 1738 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1739 1740 make TQM823L_LCD_config 1741 - will configure for a TQM823L with U-Boot console on LCD 1742 1743 make TQM823L_LCD_80MHz_config 1744 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1745 1746 etc. 1747 1748 1749 1750Finally, type "make all", and you should get some working U-Boot 1751images ready for downlod to / installation on your system: 1752 1753- "u-boot.bin" is a raw binary image 1754- "u-boot" is an image in ELF binary format 1755- "u-boot.srec" is in Motorola S-Record format 1756 1757 1758Please be aware that the Makefiles assume you are using GNU make, so 1759for instance on NetBSD you might need to use "gmake" instead of 1760native "make". 1761 1762 1763If the system board that you have is not listed, then you will need 1764to port U-Boot to your hardware platform. To do this, follow these 1765steps: 1766 17671. Add a new configuration option for your board to the toplevel 1768 "Makefile", using the existing entries as examples. 17692. Create a new directory to hold your board specific code. Add any 1770 files you need. 17713. If you're porting U-Boot to a new CPU, then also create a new 1772 directory to hold your CPU specific code. Add any files you need. 17734. Run "make config_name" with your new name. 17745. Type "make", and you should get a working "u-boot.srec" file 1775 to be installed on your target system. 1776 [Of course, this last step is much harder than it sounds.] 1777 1778 1779Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1780============================================================== 1781 1782If you have modified U-Boot sources (for instance added a new board 1783or support for new devices, a new CPU, etc.) you are expected to 1784provide feedback to the other developers. The feedback normally takes 1785the form of a "patch", i. e. a context diff against a certain (latest 1786official or latest in CVS) version of U-Boot sources. 1787 1788But before you submit such a patch, please verify that your modifi- 1789cation did not break existing code. At least make sure that *ALL* of 1790the supported boards compile WITHOUT ANY compiler warnings. To do so, 1791just run the "MAKEALL" script, which will configure and build U-Boot 1792for ALL supported system. Be warned, this will take a while. You can 1793select which (cross) compiler to use py passing a `CROSS_COMPILE' 1794environment variable to the script, i. e. to use the cross tools from 1795MontaVista's Hard Hat Linux you can type 1796 1797 CROSS_COMPILE=ppc_8xx- MAKEALL 1798 1799or to build on a native PowerPC system you can type 1800 1801 CROSS_COMPILE=' ' MAKEALL 1802 1803See also "U-Boot Porting Guide" below. 1804 1805 1806 1807Monitor Commands - Overview: 1808============================ 1809 1810go - start application at address 'addr' 1811run - run commands in an environment variable 1812bootm - boot application image from memory 1813bootp - boot image via network using BootP/TFTP protocol 1814tftpboot- boot image via network using TFTP protocol 1815 and env variables "ipaddr" and "serverip" 1816 (and eventually "gatewayip") 1817rarpboot- boot image via network using RARP/TFTP protocol 1818diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1819loads - load S-Record file over serial line 1820loadb - load binary file over serial line (kermit mode) 1821md - memory display 1822mm - memory modify (auto-incrementing) 1823nm - memory modify (constant address) 1824mw - memory write (fill) 1825cp - memory copy 1826cmp - memory compare 1827crc32 - checksum calculation 1828imd - i2c memory display 1829imm - i2c memory modify (auto-incrementing) 1830inm - i2c memory modify (constant address) 1831imw - i2c memory write (fill) 1832icrc32 - i2c checksum calculation 1833iprobe - probe to discover valid I2C chip addresses 1834iloop - infinite loop on address range 1835isdram - print SDRAM configuration information 1836sspi - SPI utility commands 1837base - print or set address offset 1838printenv- print environment variables 1839setenv - set environment variables 1840saveenv - save environment variables to persistent storage 1841protect - enable or disable FLASH write protection 1842erase - erase FLASH memory 1843flinfo - print FLASH memory information 1844bdinfo - print Board Info structure 1845iminfo - print header information for application image 1846coninfo - print console devices and informations 1847ide - IDE sub-system 1848loop - infinite loop on address range 1849mtest - simple RAM test 1850icache - enable or disable instruction cache 1851dcache - enable or disable data cache 1852reset - Perform RESET of the CPU 1853echo - echo args to console 1854version - print monitor version 1855help - print online help 1856? - alias for 'help' 1857 1858 1859Monitor Commands - Detailed Description: 1860======================================== 1861 1862TODO. 1863 1864For now: just type "help <command>". 1865 1866 1867Environment Variables: 1868====================== 1869 1870U-Boot supports user configuration using Environment Variables which 1871can be made persistent by saving to Flash memory. 1872 1873Environment Variables are set using "setenv", printed using 1874"printenv", and saved to Flash using "saveenv". Using "setenv" 1875without a value can be used to delete a variable from the 1876environment. As long as you don't save the environment you are 1877working with an in-memory copy. In case the Flash area containing the 1878environment is erased by accident, a default environment is provided. 1879 1880Some configuration options can be set using Environment Variables: 1881 1882 baudrate - see CONFIG_BAUDRATE 1883 1884 bootdelay - see CONFIG_BOOTDELAY 1885 1886 bootcmd - see CONFIG_BOOTCOMMAND 1887 1888 bootargs - Boot arguments when booting an RTOS image 1889 1890 bootfile - Name of the image to load with TFTP 1891 1892 autoload - if set to "no" (any string beginning with 'n'), 1893 "bootp" will just load perform a lookup of the 1894 configuration from the BOOTP server, but not try to 1895 load any image using TFTP 1896 1897 autostart - if set to "yes", an image loaded using the "bootp", 1898 "rarpboot", "tftpboot" or "diskboot" commands will 1899 be automatically started (by internally calling 1900 "bootm") 1901 1902 initrd_high - restrict positioning of initrd images: 1903 If this variable is not set, initrd images will be 1904 copied to the highest possible address in RAM; this 1905 is usually what you want since it allows for 1906 maximum initrd size. If for some reason you want to 1907 make sure that the initrd image is loaded below the 1908 CFG_BOOTMAPSZ limit, you can set this environment 1909 variable to a value of "no" or "off" or "0". 1910 Alternatively, you can set it to a maximum upper 1911 address to use (U-Boot will still check that it 1912 does not overwrite the U-Boot stack and data). 1913 1914 For instance, when you have a system with 16 MB 1915 RAM, and want to reseve 4 MB from use by Linux, 1916 you can do this by adding "mem=12M" to the value of 1917 the "bootargs" variable. However, now you must make 1918 sure, that the initrd image is placed in the first 1919 12 MB as well - this can be done with 1920 1921 setenv initrd_high 00c00000 1922 1923 ipaddr - IP address; needed for tftpboot command 1924 1925 loadaddr - Default load address for commands like "bootp", 1926 "rarpboot", "tftpboot" or "diskboot" 1927 1928 loads_echo - see CONFIG_LOADS_ECHO 1929 1930 serverip - TFTP server IP address; needed for tftpboot command 1931 1932 bootretry - see CONFIG_BOOT_RETRY_TIME 1933 1934 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1935 1936 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1937 1938 1939The following environment variables may be used and automatically 1940updated by the network boot commands ("bootp" and "rarpboot"), 1941depending the information provided by your boot server: 1942 1943 bootfile - see above 1944 dnsip - IP address of your Domain Name Server 1945 gatewayip - IP address of the Gateway (Router) to use 1946 hostname - Target hostname 1947 ipaddr - see above 1948 netmask - Subnet Mask 1949 rootpath - Pathname of the root filesystem on the NFS server 1950 serverip - see above 1951 1952 1953There are two special Environment Variables: 1954 1955 serial# - contains hardware identification information such 1956 as type string and/or serial number 1957 ethaddr - Ethernet address 1958 1959These variables can be set only once (usually during manufacturing of 1960the board). U-Boot refuses to delete or overwrite these variables 1961once they have been set once. 1962 1963 1964Please note that changes to some configuration parameters may take 1965only effect after the next boot (yes, that's just like Windoze :-). 1966 1967 1968Note for Redundant Ethernet Interfaces: 1969======================================= 1970 1971Some boards come with redundand ethernet interfaces; U-Boot supports 1972such configurations and is capable of automatic selection of a 1973"working" interface when needed. MAC assignemnt works as follows: 1974 1975Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1976MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1977"eth1addr" (=>eth1), "eth2addr", ... 1978 1979If the network interface stores some valid MAC address (for instance 1980in SROM), this is used as default address if there is NO correspon- 1981ding setting in the environment; if the corresponding environment 1982variable is set, this overrides the settings in the card; that means: 1983 1984o If the SROM has a valid MAC address, and there is no address in the 1985 environment, the SROM's address is used. 1986 1987o If there is no valid address in the SROM, and a definition in the 1988 environment exists, then the value from the environment variable is 1989 used. 1990 1991o If both the SROM and the environment contain a MAC address, and 1992 both addresses are the same, this MAC address is used. 1993 1994o If both the SROM and the environment contain a MAC address, and the 1995 addresses differ, the value from the environment is used and a 1996 warning is printed. 1997 1998o If neither SROM nor the environment contain a MAC address, an error 1999 is raised. 2000 2001 2002 2003Image Formats: 2004============== 2005 2006The "boot" commands of this monitor operate on "image" files which 2007can be basicly anything, preceeded by a special header; see the 2008definitions in include/image.h for details; basicly, the header 2009defines the following image properties: 2010 2011* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2012 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2013 LynxOS, pSOS, QNX; 2014 Currently supported: Linux, NetBSD, VxWorks, QNX). 2015* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2016 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2017 Currently supported: PowerPC). 2018* Compression Type (Provisions for uncompressed, gzip, bzip2; 2019 Currently supported: uncompressed, gzip). 2020* Load Address 2021* Entry Point 2022* Image Name 2023* Image Timestamp 2024 2025The header is marked by a special Magic Number, and both the header 2026and the data portions of the image are secured against corruption by 2027CRC32 checksums. 2028 2029 2030Linux Support: 2031============== 2032 2033Although U-Boot should support any OS or standalone application 2034easily, Linux has always been in the focus during the design of 2035U-Boot. 2036 2037U-Boot includes many features that so far have been part of some 2038special "boot loader" code within the Linux kernel. Also, any 2039"initrd" images to be used are no longer part of one big Linux image; 2040instead, kernel and "initrd" are separate images. This implementation 2041serves serveral purposes: 2042 2043- the same features can be used for other OS or standalone 2044 applications (for instance: using compressed images to reduce the 2045 Flash memory footprint) 2046 2047- it becomes much easier to port new Linux kernel versions because 2048 lots of low-level, hardware dependend stuff are done by U-Boot 2049 2050- the same Linux kernel image can now be used with different "initrd" 2051 images; of course this also means that different kernel images can 2052 be run with the same "initrd". This makes testing easier (you don't 2053 have to build a new "zImage.initrd" Linux image when you just 2054 change a file in your "initrd"). Also, a field-upgrade of the 2055 software is easier now. 2056 2057 2058Linux HOWTO: 2059============ 2060 2061Porting Linux to U-Boot based systems: 2062--------------------------------------- 2063 2064U-Boot cannot save you from doing all the necessary modifications to 2065configure the Linux device drivers for use with your target hardware 2066(no, we don't intend to provide a full virtual machine interface to 2067Linux :-). 2068 2069But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2070 2071Just make sure your machine specific header file (for instance 2072include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2073Information structure as we define in include/u-boot.h, and make 2074sure that your definition of IMAP_ADDR uses the same value as your 2075U-Boot configuration in CFG_IMMR. 2076 2077 2078Configuring the Linux kernel: 2079----------------------------- 2080 2081No specific requirements for U-Boot. Make sure you have some root 2082device (initial ramdisk, NFS) for your target system. 2083 2084 2085Building a Linux Image: 2086----------------------- 2087 2088With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2089not used. If you use recent kernel source, a new build target 2090"uImage" will exist which automatically builds an image usable by 2091U-Boot. Most older kernels also have support for a "pImage" target, 2092which was introduced for our predecessor project PPCBoot and uses a 2093100% compatible format. 2094 2095Example: 2096 2097 make TQM850L_config 2098 make oldconfig 2099 make dep 2100 make uImage 2101 2102The "uImage" build target uses a special tool (in 'tools/mkimage') to 2103encapsulate a compressed Linux kernel image with header information, 2104CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2105 2106* build a standard "vmlinux" kernel image (in ELF binary format): 2107 2108* convert the kernel into a raw binary image: 2109 2110 ${CROSS_COMPILE}-objcopy -O binary \ 2111 -R .note -R .comment \ 2112 -S vmlinux linux.bin 2113 2114* compress the binary image: 2115 2116 gzip -9 linux.bin 2117 2118* package compressed binary image for U-Boot: 2119 2120 mkimage -A ppc -O linux -T kernel -C gzip \ 2121 -a 0 -e 0 -n "Linux Kernel Image" \ 2122 -d linux.bin.gz uImage 2123 2124 2125The "mkimage" tool can also be used to create ramdisk images for use 2126with U-Boot, either separated from the Linux kernel image, or 2127combined into one file. "mkimage" encapsulates the images with a 64 2128byte header containing information about target architecture, 2129operating system, image type, compression method, entry points, time 2130stamp, CRC32 checksums, etc. 2131 2132"mkimage" can be called in two ways: to verify existing images and 2133print the header information, or to build new images. 2134 2135In the first form (with "-l" option) mkimage lists the information 2136contained in the header of an existing U-Boot image; this includes 2137checksum verification: 2138 2139 tools/mkimage -l image 2140 -l ==> list image header information 2141 2142The second form (with "-d" option) is used to build a U-Boot image 2143from a "data file" which is used as image payload: 2144 2145 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2146 -n name -d data_file image 2147 -A ==> set architecture to 'arch' 2148 -O ==> set operating system to 'os' 2149 -T ==> set image type to 'type' 2150 -C ==> set compression type 'comp' 2151 -a ==> set load address to 'addr' (hex) 2152 -e ==> set entry point to 'ep' (hex) 2153 -n ==> set image name to 'name' 2154 -d ==> use image data from 'datafile' 2155 2156Right now, all Linux kernels use the same load address (0x00000000), 2157but the entry point address depends on the kernel version: 2158 2159- 2.2.x kernels have the entry point at 0x0000000C, 2160- 2.3.x and later kernels have the entry point at 0x00000000. 2161 2162So a typical call to build a U-Boot image would read: 2163 2164 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2165 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2166 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2167 > examples/uImage.TQM850L 2168 Image Name: 2.4.4 kernel for TQM850L 2169 Created: Wed Jul 19 02:34:59 2000 2170 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2171 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2172 Load Address: 0x00000000 2173 Entry Point: 0x00000000 2174 2175To verify the contents of the image (or check for corruption): 2176 2177 -> tools/mkimage -l examples/uImage.TQM850L 2178 Image Name: 2.4.4 kernel for TQM850L 2179 Created: Wed Jul 19 02:34:59 2000 2180 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2181 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2182 Load Address: 0x00000000 2183 Entry Point: 0x00000000 2184 2185NOTE: for embedded systems where boot time is critical you can trade 2186speed for memory and install an UNCOMPRESSED image instead: this 2187needs more space in Flash, but boots much faster since it does not 2188need to be uncompressed: 2189 2190 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2191 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2192 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2193 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2194 > examples/uImage.TQM850L-uncompressed 2195 Image Name: 2.4.4 kernel for TQM850L 2196 Created: Wed Jul 19 02:34:59 2000 2197 Image Type: PowerPC Linux Kernel Image (uncompressed) 2198 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2199 Load Address: 0x00000000 2200 Entry Point: 0x00000000 2201 2202 2203Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2204when your kernel is intended to use an initial ramdisk: 2205 2206 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2207 > -A ppc -O linux -T ramdisk -C gzip \ 2208 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2209 Image Name: Simple Ramdisk Image 2210 Created: Wed Jan 12 14:01:50 2000 2211 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2212 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2213 Load Address: 0x00000000 2214 Entry Point: 0x00000000 2215 2216 2217Installing a Linux Image: 2218------------------------- 2219 2220To downloading a U-Boot image over the serial (console) interface, 2221you must convert the image to S-Record format: 2222 2223 objcopy -I binary -O srec examples/image examples/image.srec 2224 2225The 'objcopy' does not understand the information in the U-Boot 2226image header, so the resulting S-Record file will be relative to 2227address 0x00000000. To load it to a given address, you need to 2228specify the target address as 'offset' parameter with the 'loads' 2229command. 2230 2231Example: install the image to address 0x40100000 (which on the 2232TQM8xxL is in the first Flash bank): 2233 2234 => erase 40100000 401FFFFF 2235 2236 .......... done 2237 Erased 8 sectors 2238 2239 => loads 40100000 2240 ## Ready for S-Record download ... 2241 ~>examples/image.srec 2242 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2243 ... 2244 15989 15990 15991 15992 2245 [file transfer complete] 2246 [connected] 2247 ## Start Addr = 0x00000000 2248 2249 2250You can check the success of the download using the 'iminfo' command; 2251this includes a checksum verification so you can be sure no data 2252corruption happened: 2253 2254 => imi 40100000 2255 2256 ## Checking Image at 40100000 ... 2257 Image Name: 2.2.13 for initrd on TQM850L 2258 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2259 Data Size: 335725 Bytes = 327 kB = 0 MB 2260 Load Address: 00000000 2261 Entry Point: 0000000c 2262 Verifying Checksum ... OK 2263 2264 2265 2266Boot Linux: 2267----------- 2268 2269The "bootm" command is used to boot an application that is stored in 2270memory (RAM or Flash). In case of a Linux kernel image, the contents 2271of the "bootargs" environment variable is passed to the kernel as 2272parameters. You can check and modify this variable using the 2273"printenv" and "setenv" commands: 2274 2275 2276 => printenv bootargs 2277 bootargs=root=/dev/ram 2278 2279 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2280 2281 => printenv bootargs 2282 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2283 2284 => bootm 40020000 2285 ## Booting Linux kernel at 40020000 ... 2286 Image Name: 2.2.13 for NFS on TQM850L 2287 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2288 Data Size: 381681 Bytes = 372 kB = 0 MB 2289 Load Address: 00000000 2290 Entry Point: 0000000c 2291 Verifying Checksum ... OK 2292 Uncompressing Kernel Image ... OK 2293 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 2294 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2295 time_init: decrementer frequency = 187500000/60 2296 Calibrating delay loop... 49.77 BogoMIPS 2297 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2298 ... 2299 2300If you want to boot a Linux kernel with initial ram disk, you pass 2301the memory addreses of both the kernel and the initrd image (PPBCOOT 2302format!) to the "bootm" command: 2303 2304 => imi 40100000 40200000 2305 2306 ## Checking Image at 40100000 ... 2307 Image Name: 2.2.13 for initrd on TQM850L 2308 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2309 Data Size: 335725 Bytes = 327 kB = 0 MB 2310 Load Address: 00000000 2311 Entry Point: 0000000c 2312 Verifying Checksum ... OK 2313 2314 ## Checking Image at 40200000 ... 2315 Image Name: Simple Ramdisk Image 2316 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2317 Data Size: 566530 Bytes = 553 kB = 0 MB 2318 Load Address: 00000000 2319 Entry Point: 00000000 2320 Verifying Checksum ... OK 2321 2322 => bootm 40100000 40200000 2323 ## Booting Linux kernel at 40100000 ... 2324 Image Name: 2.2.13 for initrd on TQM850L 2325 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2326 Data Size: 335725 Bytes = 327 kB = 0 MB 2327 Load Address: 00000000 2328 Entry Point: 0000000c 2329 Verifying Checksum ... OK 2330 Uncompressing Kernel Image ... OK 2331 ## Loading RAMDisk Image at 40200000 ... 2332 Image Name: Simple Ramdisk Image 2333 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2334 Data Size: 566530 Bytes = 553 kB = 0 MB 2335 Load Address: 00000000 2336 Entry Point: 00000000 2337 Verifying Checksum ... OK 2338 Loading Ramdisk ... OK 2339 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 2340 Boot arguments: root=/dev/ram 2341 time_init: decrementer frequency = 187500000/60 2342 Calibrating delay loop... 49.77 BogoMIPS 2343 ... 2344 RAMDISK: Compressed image found at block 0 2345 VFS: Mounted root (ext2 filesystem). 2346 2347 bash# 2348 2349More About U-Boot Image Types: 2350------------------------------ 2351 2352U-Boot supports the following image types: 2353 2354 "Standalone Programs" are directly runnable in the environment 2355 provided by U-Boot; it is expected that (if they behave 2356 well) you can continue to work in U-Boot after return from 2357 the Standalone Program. 2358 "OS Kernel Images" are usually images of some Embedded OS which 2359 will take over control completely. Usually these programs 2360 will install their own set of exception handlers, device 2361 drivers, set up the MMU, etc. - this means, that you cannot 2362 expect to re-enter U-Boot except by resetting the CPU. 2363 "RAMDisk Images" are more or less just data blocks, and their 2364 parameters (address, size) are passed to an OS kernel that is 2365 being started. 2366 "Multi-File Images" contain several images, typically an OS 2367 (Linux) kernel image and one or more data images like 2368 RAMDisks. This construct is useful for instance when you want 2369 to boot over the network using BOOTP etc., where the boot 2370 server provides just a single image file, but you want to get 2371 for instance an OS kernel and a RAMDisk image. 2372 2373 "Multi-File Images" start with a list of image sizes, each 2374 image size (in bytes) specified by an "uint32_t" in network 2375 byte order. This list is terminated by an "(uint32_t)0". 2376 Immediately after the terminating 0 follow the images, one by 2377 one, all aligned on "uint32_t" boundaries (size rounded up to 2378 a multiple of 4 bytes). 2379 2380 "Firmware Images" are binary images containing firmware (like 2381 U-Boot or FPGA images) which usually will be programmed to 2382 flash memory. 2383 2384 "Script files" are command sequences that will be executed by 2385 U-Boot's command interpreter; this feature is especially 2386 useful when you configure U-Boot to use a real shell (hush) 2387 as command interpreter. 2388 2389 2390Standalone HOWTO: 2391================= 2392 2393One of the features of U-Boot is that you can dynamically load and 2394run "standalone" applications, which can use some resources of 2395U-Boot like console I/O functions or interrupt services. 2396 2397Two simple examples are included with the sources: 2398 2399"Hello World" Demo: 2400------------------- 2401 2402'examples/hello_world.c' contains a small "Hello World" Demo 2403application; it is automatically compiled when you build U-Boot. 2404It's configured to run at address 0x00040004, so you can play with it 2405like that: 2406 2407 => loads 2408 ## Ready for S-Record download ... 2409 ~>examples/hello_world.srec 2410 1 2 3 4 5 6 7 8 9 10 11 ... 2411 [file transfer complete] 2412 [connected] 2413 ## Start Addr = 0x00040004 2414 2415 => go 40004 Hello World! This is a test. 2416 ## Starting application at 0x00040004 ... 2417 Hello World 2418 argc = 7 2419 argv[0] = "40004" 2420 argv[1] = "Hello" 2421 argv[2] = "World!" 2422 argv[3] = "This" 2423 argv[4] = "is" 2424 argv[5] = "a" 2425 argv[6] = "test." 2426 argv[7] = "<NULL>" 2427 Hit any key to exit ... 2428 2429 ## Application terminated, rc = 0x0 2430 2431Another example, which demonstrates how to register a CPM interrupt 2432handler with the U-Boot code, can be found in 'examples/timer.c'. 2433Here, a CPM timer is set up to generate an interrupt every second. 2434The interrupt service routine is trivial, just printing a '.' 2435character, but this is just a demo program. The application can be 2436controlled by the following keys: 2437 2438 ? - print current values og the CPM Timer registers 2439 b - enable interrupts and start timer 2440 e - stop timer and disable interrupts 2441 q - quit application 2442 2443 => loads 2444 ## Ready for S-Record download ... 2445 ~>examples/timer.srec 2446 1 2 3 4 5 6 7 8 9 10 11 ... 2447 [file transfer complete] 2448 [connected] 2449 ## Start Addr = 0x00040004 2450 2451 => go 40004 2452 ## Starting application at 0x00040004 ... 2453 TIMERS=0xfff00980 2454 Using timer 1 2455 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2456 2457Hit 'b': 2458 [q, b, e, ?] Set interval 1000000 us 2459 Enabling timer 2460Hit '?': 2461 [q, b, e, ?] ........ 2462 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2463Hit '?': 2464 [q, b, e, ?] . 2465 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2466Hit '?': 2467 [q, b, e, ?] . 2468 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2469Hit '?': 2470 [q, b, e, ?] . 2471 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2472Hit 'e': 2473 [q, b, e, ?] ...Stopping timer 2474Hit 'q': 2475 [q, b, e, ?] ## Application terminated, rc = 0x0 2476 2477 2478NetBSD Notes: 2479============= 2480 2481Starting at version 0.9.2, U-Boot supports NetBSD both as host 2482(build U-Boot) and target system (boots NetBSD/mpc8xx). 2483 2484Building requires a cross environment; it is known to work on 2485NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2486need gmake since the Makefiles are not compatible with BSD make). 2487Note that the cross-powerpc package does not install include files; 2488attempting to build U-Boot will fail because <machine/ansi.h> is 2489missing. This file has to be installed and patched manually: 2490 2491 # cd /usr/pkg/cross/powerpc-netbsd/include 2492 # mkdir powerpc 2493 # ln -s powerpc machine 2494 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2495 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2496 2497Native builds *don't* work due to incompatibilities between native 2498and U-Boot include files. 2499 2500Booting assumes that (the first part of) the image booted is a 2501stage-2 loader which in turn loads and then invokes the kernel 2502proper. Loader sources will eventually appear in the NetBSD source 2503tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2504meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2505details. 2506 2507 2508Implementation Internals: 2509========================= 2510 2511The following is not intended to be a complete description of every 2512implementation detail. However, it should help to understand the 2513inner workings of U-Boot and make it easier to port it to custom 2514hardware. 2515 2516 2517Initial Stack, Global Data: 2518--------------------------- 2519 2520The implementation of U-Boot is complicated by the fact that U-Boot 2521starts running out of ROM (flash memory), usually without access to 2522system RAM (because the memory controller is not initialized yet). 2523This means that we don't have writable Data or BSS segments, and BSS 2524is not initialized as zero. To be able to get a C environment working 2525at all, we have to allocate at least a minimal stack. Implementation 2526options for this are defined and restricted by the CPU used: Some CPU 2527models provide on-chip memory (like the IMMR area on MPC8xx and 2528MPC826x processors), on others (parts of) the data cache can be 2529locked as (mis-) used as memory, etc. 2530 2531 Chris Hallinan posted a good summy of these issues to the 2532 u-boot-users mailing list: 2533 2534 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 2535 From: "Chris Hallinan" <clh@net1plus.com> 2536 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 2537 ... 2538 2539 Correct me if I'm wrong, folks, but the way I understand it 2540 is this: Using DCACHE as initial RAM for Stack, etc, does not 2541 require any physical RAM backing up the cache. The cleverness 2542 is that the cache is being used as a temporary supply of 2543 necessary storage before the SDRAM controller is setup. It's 2544 beyond the scope of this list to expain the details, but you 2545 can see how this works by studying the cache architecture and 2546 operation in the architecture and processor-specific manuals. 2547 2548 OCM is On Chip Memory, which I believe the 405GP has 4K. It 2549 is another option for the system designer to use as an 2550 initial stack/ram area prior to SDRAM being available. Either 2551 option should work for you. Using CS 4 should be fine if your 2552 board designers haven't used it for something that would 2553 cause you grief during the initial boot! It is frequently not 2554 used. 2555 2556 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 2557 with your processor/board/system design. The default value 2558 you will find in any recent u-boot distribution in 2559 Walnut405.h should work for you. I'd set it to a value larger 2560 than your SDRAM module. If you have a 64MB SDRAM module, set 2561 it above 400_0000. Just make sure your board has no resources 2562 that are supposed to respond to that address! That code in 2563 start.S has been around a while and should work as is when 2564 you get the config right. 2565 2566 -Chris Hallinan 2567 DS4.COM, Inc. 2568 2569It is essential to remember this, since it has some impact on the C 2570code for the initialization procedures: 2571 2572* Initialized global data (data segment) is read-only. Do not attempt 2573 to write it. 2574 2575* Do not use any unitialized global data (or implicitely initialized 2576 as zero data - BSS segment) at all - this is undefined, initiali- 2577 zation is performed later (when relocationg to RAM). 2578 2579* Stack space is very limited. Avoid big data buffers or things like 2580 that. 2581 2582Having only the stack as writable memory limits means we cannot use 2583normal global data to share information beween the code. But it 2584turned out that the implementation of U-Boot can be greatly 2585simplified by making a global data structure (gd_t) available to all 2586functions. We could pass a pointer to this data as argument to _all_ 2587functions, but this would bloat the code. Instead we use a feature of 2588the GCC compiler (Global Register Variables) to share the data: we 2589place a pointer (gd) to the global data into a register which we 2590reserve for this purpose. 2591 2592When chosing a register for such a purpose we are restricted by the 2593relevant (E)ABI specifications for the current architecture, and by 2594GCC's implementation. 2595 2596For PowerPC, the following registers have specific use: 2597 R1: stack pointer 2598 R2: TOC pointer 2599 R3-R4: parameter passing and return values 2600 R5-R10: parameter passing 2601 R13: small data area pointer 2602 R30: GOT pointer 2603 R31: frame pointer 2604 2605 (U-Boot also uses R14 as internal GOT pointer.) 2606 2607 ==> U-Boot will use R29 to hold a pointer to the global data 2608 2609 Note: on PPC, we could use a static initializer (since the 2610 address of the global data structure is known at compile time), 2611 but it turned out that reserving a register results in somewhat 2612 smaller code - although the code savings are not that big (on 2613 average for all boards 752 bytes for the whole U-Boot image, 2614 624 text + 127 data). 2615 2616On ARM, the following registers are used: 2617 2618 R0: function argument word/integer result 2619 R1-R3: function argument word 2620 R9: GOT pointer 2621 R10: stack limit (used only if stack checking if enabled) 2622 R11: argument (frame) pointer 2623 R12: temporary workspace 2624 R13: stack pointer 2625 R14: link register 2626 R15: program counter 2627 2628 ==> U-Boot will use R8 to hold a pointer to the global data 2629 2630 2631 2632Memory Management: 2633------------------ 2634 2635U-Boot runs in system state and uses physical addresses, i.e. the 2636MMU is not used either for address mapping nor for memory protection. 2637 2638The available memory is mapped to fixed addresses using the memory 2639controller. In this process, a contiguous block is formed for each 2640memory type (Flash, SDRAM, SRAM), even when it consists of several 2641physical memory banks. 2642 2643U-Boot is installed in the first 128 kB of the first Flash bank (on 2644TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2645booting and sizing and initializing DRAM, the code relocates itself 2646to the upper end of DRAM. Immediately below the U-Boot code some 2647memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2648configuration setting]. Below that, a structure with global Board 2649Info data is placed, followed by the stack (growing downward). 2650 2651Additionally, some exception handler code is copied to the low 8 kB 2652of DRAM (0x00000000 ... 0x00001FFF). 2653 2654So a typical memory configuration with 16 MB of DRAM could look like 2655this: 2656 2657 0x0000 0000 Exception Vector code 2658 : 2659 0x0000 1FFF 2660 0x0000 2000 Free for Application Use 2661 : 2662 : 2663 2664 : 2665 : 2666 0x00FB FF20 Monitor Stack (Growing downward) 2667 0x00FB FFAC Board Info Data and permanent copy of global data 2668 0x00FC 0000 Malloc Arena 2669 : 2670 0x00FD FFFF 2671 0x00FE 0000 RAM Copy of Monitor Code 2672 ... eventually: LCD or video framebuffer 2673 ... eventually: pRAM (Protected RAM - unchanged by reset) 2674 0x00FF FFFF [End of RAM] 2675 2676 2677System Initialization: 2678---------------------- 2679 2680In the reset configuration, U-Boot starts at the reset entry point 2681(on most PowerPC systens at address 0x00000100). Because of the reset 2682configuration for CS0# this is a mirror of the onboard Flash memory. 2683To be able to re-map memory U-Boot then jumps to it's link address. 2684To be able to implement the initialization code in C, a (small!) 2685initial stack is set up in the internal Dual Ported RAM (in case CPUs 2686which provide such a feature like MPC8xx or MPC8260), or in a locked 2687part of the data cache. After that, U-Boot initializes the CPU core, 2688the caches and the SIU. 2689 2690Next, all (potentially) available memory banks are mapped using a 2691preliminary mapping. For example, we put them on 512 MB boundaries 2692(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2693on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2694programmed for SDRAM access. Using the temporary configuration, a 2695simple memory test is run that determines the size of the SDRAM 2696banks. 2697 2698When there is more than one SDRAM bank, and the banks are of 2699different size, the larger is mapped first. For equal size, the first 2700bank (CS2#) is mapped first. The first mapping is always for address 27010x00000000, with any additional banks following immediately to create 2702contiguous memory starting from 0. 2703 2704Then, the monitor installs itself at the upper end of the SDRAM area 2705and allocates memory for use by malloc() and for the global Board 2706Info data; also, the exception vector code is copied to the low RAM 2707pages, and the final stack is set up. 2708 2709Only after this relocation will you have a "normal" C environment; 2710until that you are restricted in several ways, mostly because you are 2711running from ROM, and because the code will have to be relocated to a 2712new address in RAM. 2713 2714 2715U-Boot Porting Guide: 2716---------------------- 2717 2718[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2719list, October 2002] 2720 2721 2722int main (int argc, char *argv[]) 2723{ 2724 sighandler_t no_more_time; 2725 2726 signal (SIGALRM, no_more_time); 2727 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2728 2729 if (available_money > available_manpower) { 2730 pay consultant to port U-Boot; 2731 return 0; 2732 } 2733 2734 Download latest U-Boot source; 2735 2736 Subscribe to u-boot-users mailing list; 2737 2738 if (clueless) { 2739 email ("Hi, I am new to U-Boot, how do I get started?"); 2740 } 2741 2742 while (learning) { 2743 Read the README file in the top level directory; 2744 Read http://www.denx.de/re/DPLG.html 2745 Read the source, Luke; 2746 } 2747 2748 if (available_money > toLocalCurrency ($2500)) { 2749 Buy a BDI2000; 2750 } else { 2751 Add a lot of aggravation and time; 2752 } 2753 2754 Create your own board support subdirectory; 2755 2756 Create your own board config file; 2757 2758 while (!running) { 2759 do { 2760 Add / modify source code; 2761 } until (compiles); 2762 Debug; 2763 if (clueless) 2764 email ("Hi, I am having problems..."); 2765 } 2766 Send patch file to Wolfgang; 2767 2768 return 0; 2769} 2770 2771void no_more_time (int sig) 2772{ 2773 hire_a_guru(); 2774} 2775 2776 2777 2778Coding Standards: 2779----------------- 2780 2781All contributions to U-Boot should conform to the Linux kernel 2782coding style; see the file "Documentation/CodingStyle" in your Linux 2783kernel source directory. 2784 2785Please note that U-Boot is implemented in C (and to some small parts 2786in Assembler); no C++ is used, so please do not use C++ style 2787comments (//) in your code. 2788 2789Submissions which do not conform to the standards may be returned 2790with a request to reformat the changes. 2791 2792 2793Submitting Patches: 2794------------------- 2795 2796Since the number of patches for U-Boot is growing, we need to 2797establish some rules. Submissions which do not conform to these rules 2798may be rejected, even when they contain important and valuable stuff. 2799 2800 2801When you send a patch, please include the following information with 2802it: 2803 2804* For bug fixes: a description of the bug and how your patch fixes 2805 this bug. Please try to include a way of demonstrating that the 2806 patch actually fixes something. 2807 2808* For new features: a description of the feature and your 2809 implementation. 2810 2811* A CHANGELOG entry as plaintext (separate from the patch) 2812 2813* For major contributions, your entry to the CREDITS file 2814 2815* When you add support for a new board, don't forget to add this 2816 board to the MAKEALL script, too. 2817 2818* If your patch adds new configuration options, don't forget to 2819 document these in the README file. 2820 2821* The patch itself. If you are accessing the CVS repository use "cvs 2822 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2823 version of diff does not support these options, then get the latest 2824 version of GNU diff. 2825 2826 We accept patches as plain text, MIME attachments or as uuencoded 2827 gzipped text. 2828 2829Notes: 2830 2831* Before sending the patch, run the MAKEALL script on your patched 2832 source tree and make sure that no errors or warnings are reported 2833 for any of the boards. 2834 2835* Keep your modifications to the necessary minimum: A patch 2836 containing several unrelated changes or arbitrary reformats will be 2837 returned with a request to re-formatting / split it. 2838 2839* If you modify existing code, make sure that your new code does not 2840 add to the memory footprint of the code ;-) Small is beautiful! 2841 When adding new features, these should compile conditionally only 2842 (using #ifdef), and the resulting code with the new feature 2843 disabled must not need more memory than the old code without your 2844 modification. 2845