1# 2# (C) Copyright 2000 - 2004 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 dependent files 123- common Misc architecture independent functions 124- cpu CPU specific files 125 - 74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 126 - arm720t Files specific to ARM 720 CPUs 127 - arm920t Files specific to ARM 920 CPUs 128 - arm925t Files specific to ARM 925 CPUs 129 - arm926ejs Files specific to ARM 926 CPUs 130 - at91rm9200 Files specific to Atmel AT91RM9200 CPUs 131 - i386 Files specific to i386 CPUs 132 - ixp Files specific to Intel XScale IXP CPUs 133 - mcf52x2 Files specific to Motorola ColdFire MCF52x2 CPUs 134 - mips Files specific to MIPS CPUs 135 - mpc5xx Files specific to Motorola MPC5xx CPUs 136 - mpc5xxx Files specific to Motorola MPC5xxx CPUs 137 - mpc8xx Files specific to Motorola MPC8xx CPUs 138 - mpc824x Files specific to Motorola MPC824x CPUs 139 - mpc8260 Files specific to Motorola MPC8260 CPUs 140 - mpc85xx Files specific to Motorola MPC85xx CPUs 141 - nios Files specific to Altera NIOS CPUs 142 - ppc4xx Files specific to IBM PowerPC 4xx CPUs 143 - pxa Files specific to Intel XScale PXA CPUs 144 - s3c44b0 Files specific to Samsung S3C44B0 CPUs 145 - sa1100 Files specific to Intel StrongARM SA1100 CPUs 146- disk Code for disk drive partition handling 147- doc Documentation (don't expect too much) 148- drivers Commonly used device drivers 149- dtt Digital Thermometer and Thermostat drivers 150- examples Example code for standalone applications, etc. 151- include Header Files 152- lib_arm Files generic to ARM architecture 153- lib_generic Files generic to all architectures 154- lib_i386 Files generic to i386 architecture 155- lib_m68k Files generic to m68k architecture 156- lib_mips Files generic to MIPS architecture 157- lib_nios Files generic to NIOS architecture 158- lib_ppc Files generic to PowerPC architecture 159- net Networking code 160- post Power On Self Test 161- rtc Real Time Clock drivers 162- tools Tools to build S-Record or U-Boot images, etc. 163 164Software Configuration: 165======================= 166 167Configuration is usually done using C preprocessor defines; the 168rationale behind that is to avoid dead code whenever possible. 169 170There are two classes of configuration variables: 171 172* Configuration _OPTIONS_: 173 These are selectable by the user and have names beginning with 174 "CONFIG_". 175 176* Configuration _SETTINGS_: 177 These depend on the hardware etc. and should not be meddled with if 178 you don't know what you're doing; they have names beginning with 179 "CFG_". 180 181Later we will add a configuration tool - probably similar to or even 182identical to what's used for the Linux kernel. Right now, we have to 183do the configuration by hand, which means creating some symbolic 184links and editing some configuration files. We use the TQM8xxL boards 185as an example here. 186 187 188Selection of Processor Architecture and Board Type: 189--------------------------------------------------- 190 191For all supported boards there are ready-to-use default 192configurations available; just type "make <board_name>_config". 193 194Example: For a TQM823L module type: 195 196 cd u-boot 197 make TQM823L_config 198 199For the Cogent platform, you need to specify the cpu type as well; 200e.g. "make cogent_mpc8xx_config". And also configure the cogent 201directory according to the instructions in cogent/README. 202 203 204Configuration Options: 205---------------------- 206 207Configuration depends on the combination of board and CPU type; all 208such information is kept in a configuration file 209"include/configs/<board_name>.h". 210 211Example: For a TQM823L module, all configuration settings are in 212"include/configs/TQM823L.h". 213 214 215Many of the options are named exactly as the corresponding Linux 216kernel configuration options. The intention is to make it easier to 217build a config tool - later. 218 219 220The following options need to be configured: 221 222- CPU Type: Define exactly one of 223 224 PowerPC based CPUs: 225 ------------------- 226 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 227 or CONFIG_MPC5xx 228 or CONFIG_MPC824X, CONFIG_MPC8260 229 or CONFIG_MPC85xx 230 or CONFIG_IOP480 231 or CONFIG_405GP 232 or CONFIG_405EP 233 or CONFIG_440 234 or CONFIG_MPC74xx 235 or CONFIG_750FX 236 237 ARM based CPUs: 238 --------------- 239 CONFIG_SA1110 240 CONFIG_ARM7 241 CONFIG_PXA250 242 243 MicroBlaze based CPUs: 244 ---------------------- 245 CONFIG_MICROBLAZE 246 247 248- Board Type: Define exactly one of 249 250 PowerPC based boards: 251 --------------------- 252 253 CONFIG_ADCIOP CONFIG_GEN860T CONFIG_PCI405 254 CONFIG_ADS860 CONFIG_GENIETV CONFIG_PCIPPC2 255 CONFIG_AMX860 CONFIG_GTH CONFIG_PCIPPC6 256 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e 257 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405 258 CONFIG_c2mon CONFIG_hymod CONFIG_PM826 259 CONFIG_CANBT CONFIG_IAD210 CONFIG_ppmc8260 260 CONFIG_CCM CONFIG_ICU862 CONFIG_QS823 261 CONFIG_CMI CONFIG_IP860 CONFIG_QS850 262 CONFIG_cogent_mpc8260 CONFIG_IPHASE4539 CONFIG_QS860T 263 CONFIG_cogent_mpc8xx CONFIG_IVML24 CONFIG_RBC823 264 CONFIG_CPCI405 CONFIG_IVML24_128 CONFIG_RPXClassic 265 CONFIG_CPCI4052 CONFIG_IVML24_256 CONFIG_RPXlite 266 CONFIG_CPCIISER4 CONFIG_IVMS8 CONFIG_RPXsuper 267 CONFIG_CPU86 CONFIG_IVMS8_128 CONFIG_rsdproto 268 CONFIG_CRAYL1 CONFIG_IVMS8_256 CONFIG_sacsng 269 CONFIG_CSB272 CONFIG_JSE CONFIG_Sandpoint8240 270 CONFIG_CU824 CONFIG_LANTEC CONFIG_Sandpoint8245 271 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8260 272 CONFIG_DB64360 CONFIG_MBX CONFIG_sbc8560 273 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SM850 274 CONFIG_DU405 CONFIG_MHPC CONFIG_SPD823TS 275 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_STXGP3 276 CONFIG_EBONY CONFIG_MOUSSE CONFIG_SXNI855T 277 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM823L 278 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM8260 279 CONFIG_ep8260 CONFIG_MPC8560ADS CONFIG_TQM850L 280 CONFIG_ERIC CONFIG_MUSENKI CONFIG_TQM855L 281 CONFIG_ESTEEM192E CONFIG_MVS1 CONFIG_TQM860L 282 CONFIG_ETX094 CONFIG_NETPHONE CONFIG_TTTech 283 CONFIG_EVB64260 CONFIG_NETTA CONFIG_UTX8245 284 CONFIG_FADS823 CONFIG_NETVIA CONFIG_V37 285 CONFIG_FADS850SAR CONFIG_NX823 CONFIG_W7OLMC 286 CONFIG_FADS860T CONFIG_OCRTC CONFIG_W7OLMG 287 CONFIG_FLAGADM CONFIG_ORSG CONFIG_WALNUT405 288 CONFIG_FPS850L CONFIG_OXC CONFIG_ZPC1900 289 CONFIG_FPS860L CONFIG_ZUMA 290 291 ARM based boards: 292 ----------------- 293 294 CONFIG_AT91RM9200DK, CONFIG_CERF250, CONFIG_DNP1110, 295 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE, 296 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610, 297 CONFIG_LART, CONFIG_LPD7A400 CONFIG_LUBBOCK, 298 CONFIG_OSK_OMAP5912, CONFIG_SHANNON, CONFIG_P2_OMAP730, 299 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB, 300 CONFIG_VCMA9 301 302 MicroBlaze based boards: 303 ------------------------ 304 305 CONFIG_SUZAKU 306 307 308- CPU Module Type: (if CONFIG_COGENT is defined) 309 Define exactly one of 310 CONFIG_CMA286_60_OLD 311--- FIXME --- not tested yet: 312 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 313 CONFIG_CMA287_23, CONFIG_CMA287_50 314 315- Motherboard Type: (if CONFIG_COGENT is defined) 316 Define exactly one of 317 CONFIG_CMA101, CONFIG_CMA102 318 319- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 320 Define one or more of 321 CONFIG_CMA302 322 323- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 324 Define one or more of 325 CONFIG_LCD_HEARTBEAT - update a character position on 326 the lcd display every second with 327 a "rotator" |\-/|\-/ 328 329- Board flavour: (if CONFIG_MPC8260ADS is defined) 330 CONFIG_ADSTYPE 331 Possible values are: 332 CFG_8260ADS - original MPC8260ADS 333 CFG_8266ADS - MPC8266ADS 334 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR 335 CFG_8272ADS - MPC8272ADS 336 337- MPC824X Family Member (if CONFIG_MPC824X is defined) 338 Define exactly one of 339 CONFIG_MPC8240, CONFIG_MPC8245 340 341- 8xx CPU Options: (if using an MPC8xx cpu) 342 Define one or more of 343 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work 344 e.g. if there is no 32KHz 345 reference PIT/RTC clock 346 347- 859/866 CPU options: (if using a MPC859 or MPC866 CPU): 348 CFG_866_OSCCLK 349 CFG_866_CPUCLK_MIN 350 CFG_866_CPUCLK_MAX 351 CFG_866_CPUCLK_DEFAULT 352 See doc/README.MPC866 353 354 CFG_MEASURE_CPUCLK 355 356 Define this to measure the actual CPU clock instead 357 of relying on the correctness of the configured 358 values. Mostly useful for board bringup to make sure 359 the PLL is locked at the intended frequency. Note 360 that this requires a (stable) reference clock (32 kHz 361 RTC clock), 362 363- Linux Kernel Interface: 364 CONFIG_CLOCKS_IN_MHZ 365 366 U-Boot stores all clock information in Hz 367 internally. For binary compatibility with older Linux 368 kernels (which expect the clocks passed in the 369 bd_info data to be in MHz) the environment variable 370 "clocks_in_mhz" can be defined so that U-Boot 371 converts clock data to MHZ before passing it to the 372 Linux kernel. 373 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 374 "clocks_in_mhz=1" is automatically included in the 375 default environment. 376 377 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 378 379 When transfering memsize parameter to linux, some versions 380 expect it to be in bytes, others in MB. 381 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 382 383- Console Interface: 384 Depending on board, define exactly one serial port 385 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 386 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 387 console by defining CONFIG_8xx_CONS_NONE 388 389 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 390 port routines must be defined elsewhere 391 (i.e. serial_init(), serial_getc(), ...) 392 393 CONFIG_CFB_CONSOLE 394 Enables console device for a color framebuffer. Needs following 395 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 396 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 397 (default big endian) 398 VIDEO_HW_RECTFILL graphic chip supports 399 rectangle fill 400 (cf. smiLynxEM) 401 VIDEO_HW_BITBLT graphic chip supports 402 bit-blit (cf. smiLynxEM) 403 VIDEO_VISIBLE_COLS visible pixel columns 404 (cols=pitch) 405 VIDEO_VISIBLE_ROWS visible pixel rows 406 VIDEO_PIXEL_SIZE bytes per pixel 407 VIDEO_DATA_FORMAT graphic data format 408 (0-5, cf. cfb_console.c) 409 VIDEO_FB_ADRS framebuffer address 410 VIDEO_KBD_INIT_FCT keyboard int fct 411 (i.e. i8042_kbd_init()) 412 VIDEO_TSTC_FCT test char fct 413 (i.e. i8042_tstc) 414 VIDEO_GETC_FCT get char fct 415 (i.e. i8042_getc) 416 CONFIG_CONSOLE_CURSOR cursor drawing on/off 417 (requires blink timer 418 cf. i8042.c) 419 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 420 CONFIG_CONSOLE_TIME display time/date info in 421 upper right corner 422 (requires CFG_CMD_DATE) 423 CONFIG_VIDEO_LOGO display Linux logo in 424 upper left corner 425 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 426 linux_logo.h for logo. 427 Requires CONFIG_VIDEO_LOGO 428 CONFIG_CONSOLE_EXTRA_INFO 429 addional board info beside 430 the logo 431 432 When CONFIG_CFB_CONSOLE is defined, video console is 433 default i/o. Serial console can be forced with 434 environment 'console=serial'. 435 436 When CONFIG_SILENT_CONSOLE is defined, all console 437 messages (by U-Boot and Linux!) can be silenced with 438 the "silent" environment variable. See 439 doc/README.silent for more information. 440 441- Console Baudrate: 442 CONFIG_BAUDRATE - in bps 443 Select one of the baudrates listed in 444 CFG_BAUDRATE_TABLE, see below. 445 CFG_BRGCLK_PRESCALE, baudrate prescale 446 447- Interrupt driven serial port input: 448 CONFIG_SERIAL_SOFTWARE_FIFO 449 450 PPC405GP only. 451 Use an interrupt handler for receiving data on the 452 serial port. It also enables using hardware handshake 453 (RTS/CTS) and UART's built-in FIFO. Set the number of 454 bytes the interrupt driven input buffer should have. 455 456 Leave undefined to disable this feature, including 457 disable the buffer and hardware handshake. 458 459- Console UART Number: 460 CONFIG_UART1_CONSOLE 461 462 IBM PPC4xx only. 463 If defined internal UART1 (and not UART0) is used 464 as default U-Boot console. 465 466- Boot Delay: CONFIG_BOOTDELAY - in seconds 467 Delay before automatically booting the default image; 468 set to -1 to disable autoboot. 469 470 See doc/README.autoboot for these options that 471 work with CONFIG_BOOTDELAY. None are required. 472 CONFIG_BOOT_RETRY_TIME 473 CONFIG_BOOT_RETRY_MIN 474 CONFIG_AUTOBOOT_KEYED 475 CONFIG_AUTOBOOT_PROMPT 476 CONFIG_AUTOBOOT_DELAY_STR 477 CONFIG_AUTOBOOT_STOP_STR 478 CONFIG_AUTOBOOT_DELAY_STR2 479 CONFIG_AUTOBOOT_STOP_STR2 480 CONFIG_ZERO_BOOTDELAY_CHECK 481 CONFIG_RESET_TO_RETRY 482 483- Autoboot Command: 484 CONFIG_BOOTCOMMAND 485 Only needed when CONFIG_BOOTDELAY is enabled; 486 define a command string that is automatically executed 487 when no character is read on the console interface 488 within "Boot Delay" after reset. 489 490 CONFIG_BOOTARGS 491 This can be used to pass arguments to the bootm 492 command. The value of CONFIG_BOOTARGS goes into the 493 environment value "bootargs". 494 495 CONFIG_RAMBOOT and CONFIG_NFSBOOT 496 The value of these goes into the environment as 497 "ramboot" and "nfsboot" respectively, and can be used 498 as a convenience, when switching between booting from 499 ram and nfs. 500 501- Pre-Boot Commands: 502 CONFIG_PREBOOT 503 504 When this option is #defined, the existence of the 505 environment variable "preboot" will be checked 506 immediately before starting the CONFIG_BOOTDELAY 507 countdown and/or running the auto-boot command resp. 508 entering interactive mode. 509 510 This feature is especially useful when "preboot" is 511 automatically generated or modified. For an example 512 see the LWMON board specific code: here "preboot" is 513 modified when the user holds down a certain 514 combination of keys on the (special) keyboard when 515 booting the systems 516 517- Serial Download Echo Mode: 518 CONFIG_LOADS_ECHO 519 If defined to 1, all characters received during a 520 serial download (using the "loads" command) are 521 echoed back. This might be needed by some terminal 522 emulations (like "cu"), but may as well just take 523 time on others. This setting #define's the initial 524 value of the "loads_echo" environment variable. 525 526- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 527 CONFIG_KGDB_BAUDRATE 528 Select one of the baudrates listed in 529 CFG_BAUDRATE_TABLE, see below. 530 531- Monitor Functions: 532 CONFIG_COMMANDS 533 Most monitor functions can be selected (or 534 de-selected) by adjusting the definition of 535 CONFIG_COMMANDS; to select individual functions, 536 #define CONFIG_COMMANDS by "OR"ing any of the 537 following values: 538 539 #define enables commands: 540 ------------------------- 541 CFG_CMD_ASKENV * ask for env variable 542 CFG_CMD_AUTOSCRIPT Autoscript Support 543 CFG_CMD_BDI bdinfo 544 CFG_CMD_BEDBUG Include BedBug Debugger 545 CFG_CMD_BMP * BMP support 546 CFG_CMD_BOOTD bootd 547 CFG_CMD_CACHE icache, dcache 548 CFG_CMD_CONSOLE coninfo 549 CFG_CMD_DATE * support for RTC, date/time... 550 CFG_CMD_DHCP DHCP support 551 CFG_CMD_DIAG * Diagnostics 552 CFG_CMD_DOC * Disk-On-Chip Support 553 CFG_CMD_DTT Digital Therm and Thermostat 554 CFG_CMD_ECHO * echo arguments 555 CFG_CMD_EEPROM * EEPROM read/write support 556 CFG_CMD_ELF bootelf, bootvx 557 CFG_CMD_ENV saveenv 558 CFG_CMD_FDC * Floppy Disk Support 559 CFG_CMD_FAT FAT partition support 560 CFG_CMD_FDOS * Dos diskette Support 561 CFG_CMD_FLASH flinfo, erase, protect 562 CFG_CMD_FPGA FPGA device initialization support 563 CFG_CMD_HWFLOW * RTS/CTS hw flow control 564 CFG_CMD_I2C * I2C serial bus support 565 CFG_CMD_IDE * IDE harddisk support 566 CFG_CMD_IMI iminfo 567 CFG_CMD_IMLS List all found images 568 CFG_CMD_IMMAP * IMMR dump support 569 CFG_CMD_IRQ * irqinfo 570 CFG_CMD_ITEST * Integer/string test of 2 values 571 CFG_CMD_JFFS2 * JFFS2 Support 572 CFG_CMD_KGDB * kgdb 573 CFG_CMD_LOADB loadb 574 CFG_CMD_LOADS loads 575 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 576 loop, loopw, mtest 577 CFG_CMD_MISC Misc functions like sleep etc 578 CFG_CMD_MMC MMC memory mapped support 579 CFG_CMD_MII MII utility commands 580 CFG_CMD_NAND * NAND support 581 CFG_CMD_NET bootp, tftpboot, rarpboot 582 CFG_CMD_PCI * pciinfo 583 CFG_CMD_PCMCIA * PCMCIA support 584 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host 585 CFG_CMD_PORTIO * Port I/O 586 CFG_CMD_REGINFO * Register dump 587 CFG_CMD_RUN run command in env variable 588 CFG_CMD_SAVES save S record dump 589 CFG_CMD_SCSI * SCSI Support 590 CFG_CMD_SDRAM * print SDRAM configuration information 591 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 592 CFG_CMD_SPI * SPI serial bus support 593 CFG_CMD_USB * USB support 594 CFG_CMD_VFD * VFD support (TRAB) 595 CFG_CMD_BSP * Board SPecific functions 596 CFG_CMD_CDP * Cisco Discover Protocol support 597 ----------------------------------------------- 598 CFG_CMD_ALL all 599 600 CONFIG_CMD_DFL Default configuration; at the moment 601 this is includes all commands, except 602 the ones marked with "*" in the list 603 above. 604 605 If you don't define CONFIG_COMMANDS it defaults to 606 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can 607 override the default settings in the respective 608 include file. 609 610 EXAMPLE: If you want all functions except of network 611 support you can write: 612 613 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 614 615 616 Note: Don't enable the "icache" and "dcache" commands 617 (configuration option CFG_CMD_CACHE) unless you know 618 what you (and your U-Boot users) are doing. Data 619 cache cannot be enabled on systems like the 8xx or 620 8260 (where accesses to the IMMR region must be 621 uncached), and it cannot be disabled on all other 622 systems where we (mis-) use the data cache to hold an 623 initial stack and some data. 624 625 626 XXX - this list needs to get updated! 627 628- Watchdog: 629 CONFIG_WATCHDOG 630 If this variable is defined, it enables watchdog 631 support. There must be support in the platform specific 632 code for a watchdog. For the 8xx and 8260 CPUs, the 633 SIU Watchdog feature is enabled in the SYPCR 634 register. 635 636- U-Boot Version: 637 CONFIG_VERSION_VARIABLE 638 If this variable is defined, an environment variable 639 named "ver" is created by U-Boot showing the U-Boot 640 version as printed by the "version" command. 641 This variable is readonly. 642 643- Real-Time Clock: 644 645 When CFG_CMD_DATE is selected, the type of the RTC 646 has to be selected, too. Define exactly one of the 647 following options: 648 649 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 650 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 651 CONFIG_RTC_MC146818 - use MC146818 RTC 652 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 653 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 654 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 655 CONFIG_RTC_DS164x - use Dallas DS164x RTC 656 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 657 658 Note that if the RTC uses I2C, then the I2C interface 659 must also be configured. See I2C Support, below. 660 661- Timestamp Support: 662 663 When CONFIG_TIMESTAMP is selected, the timestamp 664 (date and time) of an image is printed by image 665 commands like bootm or iminfo. This option is 666 automatically enabled when you select CFG_CMD_DATE . 667 668- Partition Support: 669 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 670 and/or CONFIG_ISO_PARTITION 671 672 If IDE or SCSI support is enabled (CFG_CMD_IDE or 673 CFG_CMD_SCSI) you must configure support for at least 674 one partition type as well. 675 676- IDE Reset method: 677 CONFIG_IDE_RESET_ROUTINE - this is defined in several 678 board configurations files but used nowhere! 679 680 CONFIG_IDE_RESET - is this is defined, IDE Reset will 681 be performed by calling the function 682 ide_set_reset(int reset) 683 which has to be defined in a board specific file 684 685- ATAPI Support: 686 CONFIG_ATAPI 687 688 Set this to enable ATAPI support. 689 690- LBA48 Support 691 CONFIG_LBA48 692 693 Set this to enable support for disks larger than 137GB 694 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 695 Whithout these , LBA48 support uses 32bit variables and will 'only' 696 support disks up to 2.1TB. 697 698 CFG_64BIT_LBA: 699 When enabled, makes the IDE subsystem use 64bit sector addresses. 700 Default is 32bit. 701 702- SCSI Support: 703 At the moment only there is only support for the 704 SYM53C8XX SCSI controller; define 705 CONFIG_SCSI_SYM53C8XX to enable it. 706 707 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 708 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 709 CFG_SCSI_MAX_LUN] can be adjusted to define the 710 maximum numbers of LUNs, SCSI ID's and target 711 devices. 712 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 713 714- NETWORK Support (PCI): 715 CONFIG_E1000 716 Support for Intel 8254x gigabit chips. 717 718 CONFIG_EEPRO100 719 Support for Intel 82557/82559/82559ER chips. 720 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 721 write routine for first time initialisation. 722 723 CONFIG_TULIP 724 Support for Digital 2114x chips. 725 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 726 modem chip initialisation (KS8761/QS6611). 727 728 CONFIG_NATSEMI 729 Support for National dp83815 chips. 730 731 CONFIG_NS8382X 732 Support for National dp8382[01] gigabit chips. 733 734- NETWORK Support (other): 735 736 CONFIG_DRIVER_LAN91C96 737 Support for SMSC's LAN91C96 chips. 738 739 CONFIG_LAN91C96_BASE 740 Define this to hold the physical address 741 of the LAN91C96's I/O space 742 743 CONFIG_LAN91C96_USE_32_BIT 744 Define this to enable 32 bit addressing 745 746 CONFIG_DRIVER_SMC91111 747 Support for SMSC's LAN91C111 chip 748 749 CONFIG_SMC91111_BASE 750 Define this to hold the physical address 751 of the device (I/O space) 752 753 CONFIG_SMC_USE_32_BIT 754 Define this if data bus is 32 bits 755 756 CONFIG_SMC_USE_IOFUNCS 757 Define this to use i/o functions instead of macros 758 (some hardware wont work with macros) 759 760- USB Support: 761 At the moment only the UHCI host controller is 762 supported (PIP405, MIP405, MPC5200); define 763 CONFIG_USB_UHCI to enable it. 764 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 765 end define CONFIG_USB_STORAGE to enable the USB 766 storage devices. 767 Note: 768 Supported are USB Keyboards and USB Floppy drives 769 (TEAC FD-05PUB). 770 MPC5200 USB requires additional defines: 771 CONFIG_USB_CLOCK 772 for 528 MHz Clock: 0x0001bbbb 773 CONFIG_USB_CONFIG 774 for differential drivers: 0x00001000 775 for single ended drivers: 0x00005000 776 777 778- MMC Support: 779 The MMC controller on the Intel PXA is supported. To 780 enable this define CONFIG_MMC. The MMC can be 781 accessed from the boot prompt by mapping the device 782 to physical memory similar to flash. Command line is 783 enabled with CFG_CMD_MMC. The MMC driver also works with 784 the FAT fs. This is enabled with CFG_CMD_FAT. 785 786- Keyboard Support: 787 CONFIG_ISA_KEYBOARD 788 789 Define this to enable standard (PC-Style) keyboard 790 support 791 792 CONFIG_I8042_KBD 793 Standard PC keyboard driver with US (is default) and 794 GERMAN key layout (switch via environment 'keymap=de') support. 795 Export function i8042_kbd_init, i8042_tstc and i8042_getc 796 for cfb_console. Supports cursor blinking. 797 798- Video support: 799 CONFIG_VIDEO 800 801 Define this to enable video support (for output to 802 video). 803 804 CONFIG_VIDEO_CT69000 805 806 Enable Chips & Technologies 69000 Video chip 807 808 CONFIG_VIDEO_SMI_LYNXEM 809 Enable Silicon Motion SMI 712/710/810 Video chip. The 810 video output is selected via environment 'videoout' 811 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 812 assumed. 813 814 For the CT69000 and SMI_LYNXEM drivers, videomode is 815 selected via environment 'videomode'. Two diferent ways 816 are possible: 817 - "videomode=num" 'num' is a standard LiLo mode numbers. 818 Following standard modes are supported (* is default): 819 820 Colors 640x480 800x600 1024x768 1152x864 1280x1024 821 -------------+--------------------------------------------- 822 8 bits | 0x301* 0x303 0x305 0x161 0x307 823 15 bits | 0x310 0x313 0x316 0x162 0x319 824 16 bits | 0x311 0x314 0x317 0x163 0x31A 825 24 bits | 0x312 0x315 0x318 ? 0x31B 826 -------------+--------------------------------------------- 827 (i.e. setenv videomode 317; saveenv; reset;) 828 829 - "videomode=bootargs" all the video parameters are parsed 830 from the bootargs. (See drivers/videomodes.c) 831 832 833 CONFIG_VIDEO_SED13806 834 Enable Epson SED13806 driver. This driver supports 8bpp 835 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 836 or CONFIG_VIDEO_SED13806_16BPP 837 838- Keyboard Support: 839 CONFIG_KEYBOARD 840 841 Define this to enable a custom keyboard support. 842 This simply calls drv_keyboard_init() which must be 843 defined in your board-specific files. 844 The only board using this so far is RBC823. 845 846- LCD Support: CONFIG_LCD 847 848 Define this to enable LCD support (for output to LCD 849 display); also select one of the supported displays 850 by defining one of these: 851 852 CONFIG_NEC_NL6448AC33: 853 854 NEC NL6448AC33-18. Active, color, single scan. 855 856 CONFIG_NEC_NL6448BC20 857 858 NEC NL6448BC20-08. 6.5", 640x480. 859 Active, color, single scan. 860 861 CONFIG_NEC_NL6448BC33_54 862 863 NEC NL6448BC33-54. 10.4", 640x480. 864 Active, color, single scan. 865 866 CONFIG_SHARP_16x9 867 868 Sharp 320x240. Active, color, single scan. 869 It isn't 16x9, and I am not sure what it is. 870 871 CONFIG_SHARP_LQ64D341 872 873 Sharp LQ64D341 display, 640x480. 874 Active, color, single scan. 875 876 CONFIG_HLD1045 877 878 HLD1045 display, 640x480. 879 Active, color, single scan. 880 881 CONFIG_OPTREX_BW 882 883 Optrex CBL50840-2 NF-FW 99 22 M5 884 or 885 Hitachi LMG6912RPFC-00T 886 or 887 Hitachi SP14Q002 888 889 320x240. Black & white. 890 891 Normally display is black on white background; define 892 CFG_WHITE_ON_BLACK to get it inverted. 893 894- Splash Screen Support: CONFIG_SPLASH_SCREEN 895 896 If this option is set, the environment is checked for 897 a variable "splashimage". If found, the usual display 898 of logo, copyright and system information on the LCD 899 is suppressed and the BMP image at the address 900 specified in "splashimage" is loaded instead. The 901 console is redirected to the "nulldev", too. This 902 allows for a "silent" boot where a splash screen is 903 loaded very quickly after power-on. 904 905- Compression support: 906 CONFIG_BZIP2 907 908 If this option is set, support for bzip2 compressed 909 images is included. If not, only uncompressed and gzip 910 compressed images are supported. 911 912 NOTE: the bzip2 algorithm requires a lot of RAM, so 913 the malloc area (as defined by CFG_MALLOC_LEN) should 914 be at least 4MB. 915 916- MII/PHY support: 917 CONFIG_PHY_ADDR 918 919 The address of PHY on MII bus. 920 921 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 922 923 The clock frequency of the MII bus 924 925 CONFIG_PHY_GIGE 926 927 If this option is set, support for speed/duplex 928 detection of Gigabit PHY is included. 929 930 CONFIG_PHY_RESET_DELAY 931 932 Some PHY like Intel LXT971A need extra delay after 933 reset before any MII register access is possible. 934 For such PHY, set this option to the usec delay 935 required. (minimum 300usec for LXT971A) 936 937 CONFIG_PHY_CMD_DELAY (ppc4xx) 938 939 Some PHY like Intel LXT971A need extra delay after 940 command issued before MII status register can be read 941 942- Ethernet address: 943 CONFIG_ETHADDR 944 CONFIG_ETH2ADDR 945 CONFIG_ETH3ADDR 946 947 Define a default value for ethernet address to use 948 for the respective ethernet interface, in case this 949 is not determined automatically. 950 951- IP address: 952 CONFIG_IPADDR 953 954 Define a default value for the IP address to use for 955 the default ethernet interface, in case this is not 956 determined through e.g. bootp. 957 958- Server IP address: 959 CONFIG_SERVERIP 960 961 Defines a default value for theIP address of a TFTP 962 server to contact when using the "tftboot" command. 963 964- BOOTP Recovery Mode: 965 CONFIG_BOOTP_RANDOM_DELAY 966 967 If you have many targets in a network that try to 968 boot using BOOTP, you may want to avoid that all 969 systems send out BOOTP requests at precisely the same 970 moment (which would happen for instance at recovery 971 from a power failure, when all systems will try to 972 boot, thus flooding the BOOTP server. Defining 973 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 974 inserted before sending out BOOTP requests. The 975 following delays are insterted then: 976 977 1st BOOTP request: delay 0 ... 1 sec 978 2nd BOOTP request: delay 0 ... 2 sec 979 3rd BOOTP request: delay 0 ... 4 sec 980 4th and following 981 BOOTP requests: delay 0 ... 8 sec 982 983- DHCP Advanced Options: 984 CONFIG_BOOTP_MASK 985 986 You can fine tune the DHCP functionality by adding 987 these flags to the CONFIG_BOOTP_MASK define: 988 989 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 990 serverip from a DHCP server, it is possible that more 991 than one DNS serverip is offered to the client. 992 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 993 serverip will be stored in the additional environment 994 variable "dnsip2". The first DNS serverip is always 995 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 996 is added to the CONFIG_BOOTP_MASK. 997 998 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 999 to do a dynamic update of a DNS server. To do this, they 1000 need the hostname of the DHCP requester. 1001 If CONFIG_BOOP_SEND_HOSTNAME is added to the 1002 CONFIG_BOOTP_MASK, the content of the "hostname" 1003 environment variable is passed as option 12 to 1004 the DHCP server. 1005 1006 - CDP Options: 1007 CONFIG_CDP_DEVICE_ID 1008 1009 The device id used in CDP trigger frames. 1010 1011 CONFIG_CDP_DEVICE_ID_PREFIX 1012 1013 A two character string which is prefixed to the MAC address 1014 of the device. 1015 1016 CONFIG_CDP_PORT_ID 1017 1018 A printf format string which contains the ascii name of 1019 the port. Normally is set to "eth%d" which sets 1020 eth0 for the first ethernet, eth1 for the second etc. 1021 1022 CONFIG_CDP_CAPABILITIES 1023 1024 A 32bit integer which indicates the device capabilities; 1025 0x00000010 for a normal host which does not forwards. 1026 1027 CONFIG_CDP_VERSION 1028 1029 An ascii string containing the version of the software. 1030 1031 CONFIG_CDP_PLATFORM 1032 1033 An ascii string containing the name of the platform. 1034 1035 CONFIG_CDP_TRIGGER 1036 1037 A 32bit integer sent on the trigger. 1038 1039 CONFIG_CDP_POWER_CONSUMPTION 1040 1041 A 16bit integer containing the power consumption of the 1042 device in .1 of milliwatts. 1043 1044 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1045 1046 A byte containing the id of the VLAN. 1047 1048- Status LED: CONFIG_STATUS_LED 1049 1050 Several configurations allow to display the current 1051 status using a LED. For instance, the LED will blink 1052 fast while running U-Boot code, stop blinking as 1053 soon as a reply to a BOOTP request was received, and 1054 start blinking slow once the Linux kernel is running 1055 (supported by a status LED driver in the Linux 1056 kernel). Defining CONFIG_STATUS_LED enables this 1057 feature in U-Boot. 1058 1059- CAN Support: CONFIG_CAN_DRIVER 1060 1061 Defining CONFIG_CAN_DRIVER enables CAN driver support 1062 on those systems that support this (optional) 1063 feature, like the TQM8xxL modules. 1064 1065- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1066 1067 These enable I2C serial bus commands. Defining either of 1068 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1069 include the appropriate I2C driver for the selected cpu. 1070 1071 This will allow you to use i2c commands at the u-boot 1072 command line (as long as you set CFG_CMD_I2C in 1073 CONFIG_COMMANDS) and communicate with i2c based realtime 1074 clock chips. See common/cmd_i2c.c for a description of the 1075 command line interface. 1076 1077 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 1078 1079 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1080 bit-banging) driver instead of CPM or similar hardware 1081 support for I2C. 1082 1083 There are several other quantities that must also be 1084 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1085 1086 In both cases you will need to define CFG_I2C_SPEED 1087 to be the frequency (in Hz) at which you wish your i2c bus 1088 to run and CFG_I2C_SLAVE to be the address of this node (ie 1089 the cpu's i2c node address). 1090 1091 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1092 sets the cpu up as a master node and so its address should 1093 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1094 p.16-473). So, set CFG_I2C_SLAVE to 0. 1095 1096 That's all that's required for CONFIG_HARD_I2C. 1097 1098 If you use the software i2c interface (CONFIG_SOFT_I2C) 1099 then the following macros need to be defined (examples are 1100 from include/configs/lwmon.h): 1101 1102 I2C_INIT 1103 1104 (Optional). Any commands necessary to enable the I2C 1105 controller or configure ports. 1106 1107 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1108 1109 I2C_PORT 1110 1111 (Only for MPC8260 CPU). The I/O port to use (the code 1112 assumes both bits are on the same port). Valid values 1113 are 0..3 for ports A..D. 1114 1115 I2C_ACTIVE 1116 1117 The code necessary to make the I2C data line active 1118 (driven). If the data line is open collector, this 1119 define can be null. 1120 1121 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1122 1123 I2C_TRISTATE 1124 1125 The code necessary to make the I2C data line tri-stated 1126 (inactive). If the data line is open collector, this 1127 define can be null. 1128 1129 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1130 1131 I2C_READ 1132 1133 Code that returns TRUE if the I2C data line is high, 1134 FALSE if it is low. 1135 1136 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1137 1138 I2C_SDA(bit) 1139 1140 If <bit> is TRUE, sets the I2C data line high. If it 1141 is FALSE, it clears it (low). 1142 1143 eg: #define I2C_SDA(bit) \ 1144 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1145 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1146 1147 I2C_SCL(bit) 1148 1149 If <bit> is TRUE, sets the I2C clock line high. If it 1150 is FALSE, it clears it (low). 1151 1152 eg: #define I2C_SCL(bit) \ 1153 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1154 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1155 1156 I2C_DELAY 1157 1158 This delay is invoked four times per clock cycle so this 1159 controls the rate of data transfer. The data rate thus 1160 is 1 / (I2C_DELAY * 4). Often defined to be something 1161 like: 1162 1163 #define I2C_DELAY udelay(2) 1164 1165 CFG_I2C_INIT_BOARD 1166 1167 When a board is reset during an i2c bus transfer 1168 chips might think that the current transfer is still 1169 in progress. On some boards it is possible to access 1170 the i2c SCLK line directly, either by using the 1171 processor pin as a GPIO or by having a second pin 1172 connected to the bus. If this option is defined a 1173 custom i2c_init_board() routine in boards/xxx/board.c 1174 is run early in the boot sequence. 1175 1176 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1177 1178 This option enables configuration of bi_iic_fast[] flags 1179 in u-boot bd_info structure based on u-boot environment 1180 variable "i2cfast". (see also i2cfast) 1181 1182- SPI Support: CONFIG_SPI 1183 1184 Enables SPI driver (so far only tested with 1185 SPI EEPROM, also an instance works with Crystal A/D and 1186 D/As on the SACSng board) 1187 1188 CONFIG_SPI_X 1189 1190 Enables extended (16-bit) SPI EEPROM addressing. 1191 (symmetrical to CONFIG_I2C_X) 1192 1193 CONFIG_SOFT_SPI 1194 1195 Enables a software (bit-bang) SPI driver rather than 1196 using hardware support. This is a general purpose 1197 driver that only requires three general I/O port pins 1198 (two outputs, one input) to function. If this is 1199 defined, the board configuration must define several 1200 SPI configuration items (port pins to use, etc). For 1201 an example, see include/configs/sacsng.h. 1202 1203- FPGA Support: CONFIG_FPGA_COUNT 1204 1205 Specify the number of FPGA devices to support. 1206 1207 CONFIG_FPGA 1208 1209 Used to specify the types of FPGA devices. For example, 1210 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1211 1212 CFG_FPGA_PROG_FEEDBACK 1213 1214 Enable printing of hash marks during FPGA configuration. 1215 1216 CFG_FPGA_CHECK_BUSY 1217 1218 Enable checks on FPGA configuration interface busy 1219 status by the configuration function. This option 1220 will require a board or device specific function to 1221 be written. 1222 1223 CONFIG_FPGA_DELAY 1224 1225 If defined, a function that provides delays in the FPGA 1226 configuration driver. 1227 1228 CFG_FPGA_CHECK_CTRLC 1229 Allow Control-C to interrupt FPGA configuration 1230 1231 CFG_FPGA_CHECK_ERROR 1232 1233 Check for configuration errors during FPGA bitfile 1234 loading. For example, abort during Virtex II 1235 configuration if the INIT_B line goes low (which 1236 indicated a CRC error). 1237 1238 CFG_FPGA_WAIT_INIT 1239 1240 Maximum time to wait for the INIT_B line to deassert 1241 after PROB_B has been deasserted during a Virtex II 1242 FPGA configuration sequence. The default time is 500 1243 mS. 1244 1245 CFG_FPGA_WAIT_BUSY 1246 1247 Maximum time to wait for BUSY to deassert during 1248 Virtex II FPGA configuration. The default is 5 mS. 1249 1250 CFG_FPGA_WAIT_CONFIG 1251 1252 Time to wait after FPGA configuration. The default is 1253 200 mS. 1254 1255- Configuration Management: 1256 CONFIG_IDENT_STRING 1257 1258 If defined, this string will be added to the U-Boot 1259 version information (U_BOOT_VERSION) 1260 1261- Vendor Parameter Protection: 1262 1263 U-Boot considers the values of the environment 1264 variables "serial#" (Board Serial Number) and 1265 "ethaddr" (Ethernet Address) to be parameters that 1266 are set once by the board vendor / manufacturer, and 1267 protects these variables from casual modification by 1268 the user. Once set, these variables are read-only, 1269 and write or delete attempts are rejected. You can 1270 change this behviour: 1271 1272 If CONFIG_ENV_OVERWRITE is #defined in your config 1273 file, the write protection for vendor parameters is 1274 completely disabled. Anybody can change or delete 1275 these parameters. 1276 1277 Alternatively, if you #define _both_ CONFIG_ETHADDR 1278 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1279 ethernet address is installed in the environment, 1280 which can be changed exactly ONCE by the user. [The 1281 serial# is unaffected by this, i. e. it remains 1282 read-only.] 1283 1284- Protected RAM: 1285 CONFIG_PRAM 1286 1287 Define this variable to enable the reservation of 1288 "protected RAM", i. e. RAM which is not overwritten 1289 by U-Boot. Define CONFIG_PRAM to hold the number of 1290 kB you want to reserve for pRAM. You can overwrite 1291 this default value by defining an environment 1292 variable "pram" to the number of kB you want to 1293 reserve. Note that the board info structure will 1294 still show the full amount of RAM. If pRAM is 1295 reserved, a new environment variable "mem" will 1296 automatically be defined to hold the amount of 1297 remaining RAM in a form that can be passed as boot 1298 argument to Linux, for instance like that: 1299 1300 setenv bootargs ... mem=\$(mem) 1301 saveenv 1302 1303 This way you can tell Linux not to use this memory, 1304 either, which results in a memory region that will 1305 not be affected by reboots. 1306 1307 *WARNING* If your board configuration uses automatic 1308 detection of the RAM size, you must make sure that 1309 this memory test is non-destructive. So far, the 1310 following board configurations are known to be 1311 "pRAM-clean": 1312 1313 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1314 HERMES, IP860, RPXlite, LWMON, LANTEC, 1315 PCU_E, FLAGADM, TQM8260 1316 1317- Error Recovery: 1318 CONFIG_PANIC_HANG 1319 1320 Define this variable to stop the system in case of a 1321 fatal error, so that you have to reset it manually. 1322 This is probably NOT a good idea for an embedded 1323 system where you want to system to reboot 1324 automatically as fast as possible, but it may be 1325 useful during development since you can try to debug 1326 the conditions that lead to the situation. 1327 1328 CONFIG_NET_RETRY_COUNT 1329 1330 This variable defines the number of retries for 1331 network operations like ARP, RARP, TFTP, or BOOTP 1332 before giving up the operation. If not defined, a 1333 default value of 5 is used. 1334 1335- Command Interpreter: 1336 CFG_AUTO_COMPLETE 1337 1338 Enable auto completion of commands using TAB. 1339 1340 CFG_HUSH_PARSER 1341 1342 Define this variable to enable the "hush" shell (from 1343 Busybox) as command line interpreter, thus enabling 1344 powerful command line syntax like 1345 if...then...else...fi conditionals or `&&' and '||' 1346 constructs ("shell scripts"). 1347 1348 If undefined, you get the old, much simpler behaviour 1349 with a somewhat smaller memory footprint. 1350 1351 1352 CFG_PROMPT_HUSH_PS2 1353 1354 This defines the secondary prompt string, which is 1355 printed when the command interpreter needs more input 1356 to complete a command. Usually "> ". 1357 1358 Note: 1359 1360 In the current implementation, the local variables 1361 space and global environment variables space are 1362 separated. Local variables are those you define by 1363 simply typing `name=value'. To access a local 1364 variable later on, you have write `$name' or 1365 `${name}'; to execute the contents of a variable 1366 directly type `$name' at the command prompt. 1367 1368 Global environment variables are those you use 1369 setenv/printenv to work with. To run a command stored 1370 in such a variable, you need to use the run command, 1371 and you must not use the '$' sign to access them. 1372 1373 To store commands and special characters in a 1374 variable, please use double quotation marks 1375 surrounding the whole text of the variable, instead 1376 of the backslashes before semicolons and special 1377 symbols. 1378 1379- Default Environment: 1380 CONFIG_EXTRA_ENV_SETTINGS 1381 1382 Define this to contain any number of null terminated 1383 strings (variable = value pairs) that will be part of 1384 the default environment compiled into the boot image. 1385 1386 For example, place something like this in your 1387 board's config file: 1388 1389 #define CONFIG_EXTRA_ENV_SETTINGS \ 1390 "myvar1=value1\0" \ 1391 "myvar2=value2\0" 1392 1393 Warning: This method is based on knowledge about the 1394 internal format how the environment is stored by the 1395 U-Boot code. This is NOT an official, exported 1396 interface! Although it is unlikely that this format 1397 will change soon, there is no guarantee either. 1398 You better know what you are doing here. 1399 1400 Note: overly (ab)use of the default environment is 1401 discouraged. Make sure to check other ways to preset 1402 the environment like the autoscript function or the 1403 boot command first. 1404 1405- DataFlash Support: 1406 CONFIG_HAS_DATAFLASH 1407 1408 Defining this option enables DataFlash features and 1409 allows to read/write in Dataflash via the standard 1410 commands cp, md... 1411 1412- SystemACE Support: 1413 CONFIG_SYSTEMACE 1414 1415 Adding this option adds support for Xilinx SystemACE 1416 chips attached via some sort of local bus. The address 1417 of the chip must alsh be defined in the 1418 CFG_SYSTEMACE_BASE macro. For example: 1419 1420 #define CONFIG_SYSTEMACE 1421 #define CFG_SYSTEMACE_BASE 0xf0000000 1422 1423 When SystemACE support is added, the "ace" device type 1424 becomes available to the fat commands, i.e. fatls. 1425 1426- Show boot progress: 1427 CONFIG_SHOW_BOOT_PROGRESS 1428 1429 Defining this option allows to add some board- 1430 specific code (calling a user-provided function 1431 "show_boot_progress(int)") that enables you to show 1432 the system's boot progress on some display (for 1433 example, some LED's) on your board. At the moment, 1434 the following checkpoints are implemented: 1435 1436 Arg Where When 1437 1 common/cmd_bootm.c before attempting to boot an image 1438 -1 common/cmd_bootm.c Image header has bad magic number 1439 2 common/cmd_bootm.c Image header has correct magic number 1440 -2 common/cmd_bootm.c Image header has bad checksum 1441 3 common/cmd_bootm.c Image header has correct checksum 1442 -3 common/cmd_bootm.c Image data has bad checksum 1443 4 common/cmd_bootm.c Image data has correct checksum 1444 -4 common/cmd_bootm.c Image is for unsupported architecture 1445 5 common/cmd_bootm.c Architecture check OK 1446 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1447 6 common/cmd_bootm.c Image Type check OK 1448 -6 common/cmd_bootm.c gunzip uncompression error 1449 -7 common/cmd_bootm.c Unimplemented compression type 1450 7 common/cmd_bootm.c Uncompression OK 1451 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1452 8 common/cmd_bootm.c Image Type check OK 1453 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1454 9 common/cmd_bootm.c Start initial ramdisk verification 1455 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1456 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1457 10 common/cmd_bootm.c Ramdisk header is OK 1458 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1459 11 common/cmd_bootm.c Ramdisk data has correct checksum 1460 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1461 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1462 13 common/cmd_bootm.c Start multifile image verification 1463 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1464 15 common/cmd_bootm.c All preparation done, transferring control to OS 1465 1466 -30 lib_ppc/board.c Fatal error, hang the system 1467 -31 post/post.c POST test failed, detected by post_output_backlog() 1468 -32 post/post.c POST test failed, detected by post_run_single() 1469 1470 -1 common/cmd_doc.c Bad usage of "doc" command 1471 -1 common/cmd_doc.c No boot device 1472 -1 common/cmd_doc.c Unknown Chip ID on boot device 1473 -1 common/cmd_doc.c Read Error on boot device 1474 -1 common/cmd_doc.c Image header has bad magic number 1475 1476 -1 common/cmd_ide.c Bad usage of "ide" command 1477 -1 common/cmd_ide.c No boot device 1478 -1 common/cmd_ide.c Unknown boot device 1479 -1 common/cmd_ide.c Unknown partition table 1480 -1 common/cmd_ide.c Invalid partition type 1481 -1 common/cmd_ide.c Read Error on boot device 1482 -1 common/cmd_ide.c Image header has bad magic number 1483 1484 -1 common/cmd_nand.c Bad usage of "nand" command 1485 -1 common/cmd_nand.c No boot device 1486 -1 common/cmd_nand.c Unknown Chip ID on boot device 1487 -1 common/cmd_nand.c Read Error on boot device 1488 -1 common/cmd_nand.c Image header has bad magic number 1489 1490 -1 common/env_common.c Environment has a bad CRC, using default 1491 1492 1493Modem Support: 1494-------------- 1495 1496[so far only for SMDK2400 and TRAB boards] 1497 1498- Modem support endable: 1499 CONFIG_MODEM_SUPPORT 1500 1501- RTS/CTS Flow control enable: 1502 CONFIG_HWFLOW 1503 1504- Modem debug support: 1505 CONFIG_MODEM_SUPPORT_DEBUG 1506 1507 Enables debugging stuff (char screen[1024], dbg()) 1508 for modem support. Useful only with BDI2000. 1509 1510- Interrupt support (PPC): 1511 1512 There are common interrupt_init() and timer_interrupt() 1513 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1514 for cpu specific initialization. interrupt_init_cpu() 1515 should set decrementer_count to appropriate value. If 1516 cpu resets decrementer automatically after interrupt 1517 (ppc4xx) it should set decrementer_count to zero. 1518 timer_interrupt() calls timer_interrupt_cpu() for cpu 1519 specific handling. If board has watchdog / status_led 1520 / other_activity_monitor it works automatically from 1521 general timer_interrupt(). 1522 1523- General: 1524 1525 In the target system modem support is enabled when a 1526 specific key (key combination) is pressed during 1527 power-on. Otherwise U-Boot will boot normally 1528 (autoboot). The key_pressed() fuction is called from 1529 board_init(). Currently key_pressed() is a dummy 1530 function, returning 1 and thus enabling modem 1531 initialization. 1532 1533 If there are no modem init strings in the 1534 environment, U-Boot proceed to autoboot; the 1535 previous output (banner, info printfs) will be 1536 supressed, though. 1537 1538 See also: doc/README.Modem 1539 1540 1541Configuration Settings: 1542----------------------- 1543 1544- CFG_LONGHELP: Defined when you want long help messages included; 1545 undefine this when you're short of memory. 1546 1547- CFG_PROMPT: This is what U-Boot prints on the console to 1548 prompt for user input. 1549 1550- CFG_CBSIZE: Buffer size for input from the Console 1551 1552- CFG_PBSIZE: Buffer size for Console output 1553 1554- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1555 1556- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1557 the application (usually a Linux kernel) when it is 1558 booted 1559 1560- CFG_BAUDRATE_TABLE: 1561 List of legal baudrate settings for this board. 1562 1563- CFG_CONSOLE_INFO_QUIET 1564 Suppress display of console information at boot. 1565 1566- CFG_CONSOLE_IS_IN_ENV 1567 If the board specific function 1568 extern int overwrite_console (void); 1569 returns 1, the stdin, stderr and stdout are switched to the 1570 serial port, else the settings in the environment are used. 1571 1572- CFG_CONSOLE_OVERWRITE_ROUTINE 1573 Enable the call to overwrite_console(). 1574 1575- CFG_CONSOLE_ENV_OVERWRITE 1576 Enable overwrite of previous console environment settings. 1577 1578- CFG_MEMTEST_START, CFG_MEMTEST_END: 1579 Begin and End addresses of the area used by the 1580 simple memory test. 1581 1582- CFG_ALT_MEMTEST: 1583 Enable an alternate, more extensive memory test. 1584 1585- CFG_MEMTEST_SCRATCH: 1586 Scratch address used by the alternate memory test 1587 You only need to set this if address zero isn't writeable 1588 1589- CFG_TFTP_LOADADDR: 1590 Default load address for network file downloads 1591 1592- CFG_LOADS_BAUD_CHANGE: 1593 Enable temporary baudrate change while serial download 1594 1595- CFG_SDRAM_BASE: 1596 Physical start address of SDRAM. _Must_ be 0 here. 1597 1598- CFG_MBIO_BASE: 1599 Physical start address of Motherboard I/O (if using a 1600 Cogent motherboard) 1601 1602- CFG_FLASH_BASE: 1603 Physical start address of Flash memory. 1604 1605- CFG_MONITOR_BASE: 1606 Physical start address of boot monitor code (set by 1607 make config files to be same as the text base address 1608 (TEXT_BASE) used when linking) - same as 1609 CFG_FLASH_BASE when booting from flash. 1610 1611- CFG_MONITOR_LEN: 1612 Size of memory reserved for monitor code, used to 1613 determine _at_compile_time_ (!) if the environment is 1614 embedded within the U-Boot image, or in a separate 1615 flash sector. 1616 1617- CFG_MALLOC_LEN: 1618 Size of DRAM reserved for malloc() use. 1619 1620- CFG_BOOTMAPSZ: 1621 Maximum size of memory mapped by the startup code of 1622 the Linux kernel; all data that must be processed by 1623 the Linux kernel (bd_info, boot arguments, eventually 1624 initrd image) must be put below this limit. 1625 1626- CFG_MAX_FLASH_BANKS: 1627 Max number of Flash memory banks 1628 1629- CFG_MAX_FLASH_SECT: 1630 Max number of sectors on a Flash chip 1631 1632- CFG_FLASH_ERASE_TOUT: 1633 Timeout for Flash erase operations (in ms) 1634 1635- CFG_FLASH_WRITE_TOUT: 1636 Timeout for Flash write operations (in ms) 1637 1638- CFG_FLASH_LOCK_TOUT 1639 Timeout for Flash set sector lock bit operation (in ms) 1640 1641- CFG_FLASH_UNLOCK_TOUT 1642 Timeout for Flash clear lock bits operation (in ms) 1643 1644- CFG_FLASH_PROTECTION 1645 If defined, hardware flash sectors protection is used 1646 instead of U-Boot software protection. 1647 1648- CFG_DIRECT_FLASH_TFTP: 1649 1650 Enable TFTP transfers directly to flash memory; 1651 without this option such a download has to be 1652 performed in two steps: (1) download to RAM, and (2) 1653 copy from RAM to flash. 1654 1655 The two-step approach is usually more reliable, since 1656 you can check if the download worked before you erase 1657 the flash, but in some situations (when sytem RAM is 1658 too limited to allow for a tempory copy of the 1659 downloaded image) this option may be very useful. 1660 1661- CFG_FLASH_CFI: 1662 Define if the flash driver uses extra elements in the 1663 common flash structure for storing flash geometry. 1664 1665- CFG_FLASH_CFI_DRIVER 1666 This option also enables the building of the cfi_flash driver 1667 in the drivers directory 1668 1669- CFG_RX_ETH_BUFFER: 1670 Defines the number of ethernet receive buffers. On some 1671 ethernet controllers it is recommended to set this value 1672 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1673 buffers can be full shortly after enabling the interface 1674 on high ethernet traffic. 1675 Defaults to 4 if not defined. 1676 1677The following definitions that deal with the placement and management 1678of environment data (variable area); in general, we support the 1679following configurations: 1680 1681- CFG_ENV_IS_IN_FLASH: 1682 1683 Define this if the environment is in flash memory. 1684 1685 a) The environment occupies one whole flash sector, which is 1686 "embedded" in the text segment with the U-Boot code. This 1687 happens usually with "bottom boot sector" or "top boot 1688 sector" type flash chips, which have several smaller 1689 sectors at the start or the end. For instance, such a 1690 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1691 such a case you would place the environment in one of the 1692 4 kB sectors - with U-Boot code before and after it. With 1693 "top boot sector" type flash chips, you would put the 1694 environment in one of the last sectors, leaving a gap 1695 between U-Boot and the environment. 1696 1697 - CFG_ENV_OFFSET: 1698 1699 Offset of environment data (variable area) to the 1700 beginning of flash memory; for instance, with bottom boot 1701 type flash chips the second sector can be used: the offset 1702 for this sector is given here. 1703 1704 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1705 1706 - CFG_ENV_ADDR: 1707 1708 This is just another way to specify the start address of 1709 the flash sector containing the environment (instead of 1710 CFG_ENV_OFFSET). 1711 1712 - CFG_ENV_SECT_SIZE: 1713 1714 Size of the sector containing the environment. 1715 1716 1717 b) Sometimes flash chips have few, equal sized, BIG sectors. 1718 In such a case you don't want to spend a whole sector for 1719 the environment. 1720 1721 - CFG_ENV_SIZE: 1722 1723 If you use this in combination with CFG_ENV_IS_IN_FLASH 1724 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1725 of this flash sector for the environment. This saves 1726 memory for the RAM copy of the environment. 1727 1728 It may also save flash memory if you decide to use this 1729 when your environment is "embedded" within U-Boot code, 1730 since then the remainder of the flash sector could be used 1731 for U-Boot code. It should be pointed out that this is 1732 STRONGLY DISCOURAGED from a robustness point of view: 1733 updating the environment in flash makes it always 1734 necessary to erase the WHOLE sector. If something goes 1735 wrong before the contents has been restored from a copy in 1736 RAM, your target system will be dead. 1737 1738 - CFG_ENV_ADDR_REDUND 1739 CFG_ENV_SIZE_REDUND 1740 1741 These settings describe a second storage area used to hold 1742 a redundand copy of the environment data, so that there is 1743 a valid backup copy in case there is a power failure during 1744 a "saveenv" operation. 1745 1746BE CAREFUL! Any changes to the flash layout, and some changes to the 1747source code will make it necessary to adapt <board>/u-boot.lds* 1748accordingly! 1749 1750 1751- CFG_ENV_IS_IN_NVRAM: 1752 1753 Define this if you have some non-volatile memory device 1754 (NVRAM, battery buffered SRAM) which you want to use for the 1755 environment. 1756 1757 - CFG_ENV_ADDR: 1758 - CFG_ENV_SIZE: 1759 1760 These two #defines are used to determin the memory area you 1761 want to use for environment. It is assumed that this memory 1762 can just be read and written to, without any special 1763 provision. 1764 1765BE CAREFUL! The first access to the environment happens quite early 1766in U-Boot initalization (when we try to get the setting of for the 1767console baudrate). You *MUST* have mappend your NVRAM area then, or 1768U-Boot will hang. 1769 1770Please note that even with NVRAM we still use a copy of the 1771environment in RAM: we could work on NVRAM directly, but we want to 1772keep settings there always unmodified except somebody uses "saveenv" 1773to save the current settings. 1774 1775 1776- CFG_ENV_IS_IN_EEPROM: 1777 1778 Use this if you have an EEPROM or similar serial access 1779 device and a driver for it. 1780 1781 - CFG_ENV_OFFSET: 1782 - CFG_ENV_SIZE: 1783 1784 These two #defines specify the offset and size of the 1785 environment area within the total memory of your EEPROM. 1786 1787 - CFG_I2C_EEPROM_ADDR: 1788 If defined, specified the chip address of the EEPROM device. 1789 The default address is zero. 1790 1791 - CFG_EEPROM_PAGE_WRITE_BITS: 1792 If defined, the number of bits used to address bytes in a 1793 single page in the EEPROM device. A 64 byte page, for example 1794 would require six bits. 1795 1796 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1797 If defined, the number of milliseconds to delay between 1798 page writes. The default is zero milliseconds. 1799 1800 - CFG_I2C_EEPROM_ADDR_LEN: 1801 The length in bytes of the EEPROM memory array address. Note 1802 that this is NOT the chip address length! 1803 1804 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 1805 EEPROM chips that implement "address overflow" are ones 1806 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 1807 address and the extra bits end up in the "chip address" bit 1808 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 1809 byte chips. 1810 1811 Note that we consider the length of the address field to 1812 still be one byte because the extra address bits are hidden 1813 in the chip address. 1814 1815 - CFG_EEPROM_SIZE: 1816 The size in bytes of the EEPROM device. 1817 1818 1819- CFG_ENV_IS_IN_DATAFLASH: 1820 1821 Define this if you have a DataFlash memory device which you 1822 want to use for the environment. 1823 1824 - CFG_ENV_OFFSET: 1825 - CFG_ENV_ADDR: 1826 - CFG_ENV_SIZE: 1827 1828 These three #defines specify the offset and size of the 1829 environment area within the total memory of your DataFlash placed 1830 at the specified address. 1831 1832- CFG_ENV_IS_IN_NAND: 1833 1834 Define this if you have a NAND device which you want to use 1835 for the environment. 1836 1837 - CFG_ENV_OFFSET: 1838 - CFG_ENV_SIZE: 1839 1840 These two #defines specify the offset and size of the environment 1841 area within the first NAND device. 1842 1843- CFG_SPI_INIT_OFFSET 1844 1845 Defines offset to the initial SPI buffer area in DPRAM. The 1846 area is used at an early stage (ROM part) if the environment 1847 is configured to reside in the SPI EEPROM: We need a 520 byte 1848 scratch DPRAM area. It is used between the two initialization 1849 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1850 to be a good choice since it makes it far enough from the 1851 start of the data area as well as from the stack pointer. 1852 1853Please note that the environment is read-only as long as the monitor 1854has been relocated to RAM and a RAM copy of the environment has been 1855created; also, when using EEPROM you will have to use getenv_r() 1856until then to read environment variables. 1857 1858The environment is protected by a CRC32 checksum. Before the monitor 1859is relocated into RAM, as a result of a bad CRC you will be working 1860with the compiled-in default environment - *silently*!!! [This is 1861necessary, because the first environment variable we need is the 1862"baudrate" setting for the console - if we have a bad CRC, we don't 1863have any device yet where we could complain.] 1864 1865Note: once the monitor has been relocated, then it will complain if 1866the default environment is used; a new CRC is computed as soon as you 1867use the "saveenv" command to store a valid environment. 1868 1869- CFG_FAULT_ECHO_LINK_DOWN: 1870 Echo the inverted Ethernet link state to the fault LED. 1871 1872 Note: If this option is active, then CFG_FAULT_MII_ADDR 1873 also needs to be defined. 1874 1875- CFG_FAULT_MII_ADDR: 1876 MII address of the PHY to check for the Ethernet link state. 1877 1878- CFG_64BIT_VSPRINTF: 1879 Makes vsprintf (and all *printf functions) support printing 1880 of 64bit values by using the L quantifier 1881 1882- CFG_64BIT_STRTOUL: 1883 Adds simple_strtoull that returns a 64bit value 1884 1885Low Level (hardware related) configuration options: 1886--------------------------------------------------- 1887 1888- CFG_CACHELINE_SIZE: 1889 Cache Line Size of the CPU. 1890 1891- CFG_DEFAULT_IMMR: 1892 Default address of the IMMR after system reset. 1893 1894 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1895 and RPXsuper) to be able to adjust the position of 1896 the IMMR register after a reset. 1897 1898- Floppy Disk Support: 1899 CFG_FDC_DRIVE_NUMBER 1900 1901 the default drive number (default value 0) 1902 1903 CFG_ISA_IO_STRIDE 1904 1905 defines the spacing between fdc chipset registers 1906 (default value 1) 1907 1908 CFG_ISA_IO_OFFSET 1909 1910 defines the offset of register from address. It 1911 depends on which part of the data bus is connected to 1912 the fdc chipset. (default value 0) 1913 1914 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1915 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1916 default value. 1917 1918 if CFG_FDC_HW_INIT is defined, then the function 1919 fdc_hw_init() is called at the beginning of the FDC 1920 setup. fdc_hw_init() must be provided by the board 1921 source code. It is used to make hardware dependant 1922 initializations. 1923 1924- CFG_IMMR: Physical address of the Internal Memory Mapped 1925 Register; DO NOT CHANGE! (11-4) 1926 [MPC8xx systems only] 1927 1928- CFG_INIT_RAM_ADDR: 1929 1930 Start address of memory area that can be used for 1931 initial data and stack; please note that this must be 1932 writable memory that is working WITHOUT special 1933 initialization, i. e. you CANNOT use normal RAM which 1934 will become available only after programming the 1935 memory controller and running certain initialization 1936 sequences. 1937 1938 U-Boot uses the following memory types: 1939 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1940 - MPC824X: data cache 1941 - PPC4xx: data cache 1942 1943- CFG_GBL_DATA_OFFSET: 1944 1945 Offset of the initial data structure in the memory 1946 area defined by CFG_INIT_RAM_ADDR. Usually 1947 CFG_GBL_DATA_OFFSET is chosen such that the initial 1948 data is located at the end of the available space 1949 (sometimes written as (CFG_INIT_RAM_END - 1950 CFG_INIT_DATA_SIZE), and the initial stack is just 1951 below that area (growing from (CFG_INIT_RAM_ADDR + 1952 CFG_GBL_DATA_OFFSET) downward. 1953 1954 Note: 1955 On the MPC824X (or other systems that use the data 1956 cache for initial memory) the address chosen for 1957 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1958 point to an otherwise UNUSED address space between 1959 the top of RAM and the start of the PCI space. 1960 1961- CFG_SIUMCR: SIU Module Configuration (11-6) 1962 1963- CFG_SYPCR: System Protection Control (11-9) 1964 1965- CFG_TBSCR: Time Base Status and Control (11-26) 1966 1967- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1968 1969- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1970 1971- CFG_SCCR: System Clock and reset Control Register (15-27) 1972 1973- CFG_OR_TIMING_SDRAM: 1974 SDRAM timing 1975 1976- CFG_MAMR_PTA: 1977 periodic timer for refresh 1978 1979- CFG_DER: Debug Event Register (37-47) 1980 1981- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1982 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1983 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1984 CFG_BR1_PRELIM: 1985 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1986 1987- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1988 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1989 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1990 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1991 1992- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1993 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1994 Machine Mode Register and Memory Periodic Timer 1995 Prescaler definitions (SDRAM timing) 1996 1997- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1998 enable I2C microcode relocation patch (MPC8xx); 1999 define relocation offset in DPRAM [DSP2] 2000 2001- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 2002 enable SPI microcode relocation patch (MPC8xx); 2003 define relocation offset in DPRAM [SCC4] 2004 2005- CFG_USE_OSCCLK: 2006 Use OSCM clock mode on MBX8xx board. Be careful, 2007 wrong setting might damage your board. Read 2008 doc/README.MBX before setting this variable! 2009 2010- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 2011 Offset of the bootmode word in DPRAM used by post 2012 (Power On Self Tests). This definition overrides 2013 #define'd default value in commproc.h resp. 2014 cpm_8260.h. 2015 2016- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 2017 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 2018 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 2019 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 2020 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 2021 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 2022 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 2023 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 2024 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 2025 2026- CONFIG_ETHER_ON_FEC[12] 2027 Define to enable FEC[12] on a 8xx series processor. 2028 2029- CONFIG_FEC[12]_PHY 2030 Define to the hardcoded PHY address which corresponds 2031 to the given FEC; i. e. 2032 #define CONFIG_FEC1_PHY 4 2033 means that the PHY with address 4 is connected to FEC1 2034 2035 When set to -1, means to probe for first available. 2036 2037- CONFIG_FEC[12]_PHY_NORXERR 2038 The PHY does not have a RXERR line (RMII only). 2039 (so program the FEC to ignore it). 2040 2041- CONFIG_RMII 2042 Enable RMII mode for all FECs. 2043 Note that this is a global option, we can't 2044 have one FEC in standard MII mode and another in RMII mode. 2045 2046- CONFIG_CRC32_VERIFY 2047 Add a verify option to the crc32 command. 2048 The syntax is: 2049 2050 => crc32 -v <address> <count> <crc32> 2051 2052 Where address/count indicate a memory area 2053 and crc32 is the correct crc32 which the 2054 area should have. 2055 2056- CONFIG_LOOPW 2057 Add the "loopw" memory command. This only takes effect if 2058 the memory commands are activated globally (CFG_CMD_MEM). 2059 2060Building the Software: 2061====================== 2062 2063Building U-Boot has been tested in native PPC environments (on a 2064PowerBook G3 running LinuxPPC 2000) and in cross environments 2065(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2066NetBSD 1.5 on x86). 2067 2068If you are not using a native PPC environment, it is assumed that you 2069have the GNU cross compiling tools available in your path and named 2070with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2071you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2072the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2073change it to: 2074 2075 CROSS_COMPILE = ppc_4xx- 2076 2077 2078U-Boot is intended to be simple to build. After installing the 2079sources you must configure U-Boot for one specific board type. This 2080is done by typing: 2081 2082 make NAME_config 2083 2084where "NAME_config" is the name of one of the existing 2085configurations; the following names are supported: 2086 2087 ADCIOP_config FPS860L_config omap730p2_config 2088 ADS860_config GEN860T_config pcu_e_config 2089 AR405_config GENIETV_config PIP405_config 2090 at91rm9200dk_config GTH_config QS823_config 2091 CANBT_config hermes_config QS850_config 2092 cmi_mpc5xx_config hymod_config QS860T_config 2093 cogent_common_config IP860_config RPXlite_config 2094 cogent_mpc8260_config IVML24_config RPXlite_DW_config 2095 cogent_mpc8xx_config IVMS8_config RPXsuper_config 2096 CPCI405_config JSE_config rsdproto_config 2097 CPCIISER4_config LANTEC_config Sandpoint8240_config 2098 csb272_config lwmon_config sbc8260_config 2099 CU824_config MBX860T_config sbc8560_33_config 2100 DUET_ADS_config MBX_config sbc8560_66_config 2101 EBONY_config MPC8260ADS_config SM850_config 2102 ELPT860_config MPC8540ADS_config SPD823TS_config 2103 ESTEEM192E_config MPC8560ADS_config stxgp3_config 2104 ETX094_config NETVIA_config SXNI855T_config 2105 FADS823_config omap1510inn_config TQM823L_config 2106 FADS850SAR_config omap1610h2_config TQM850L_config 2107 FADS860T_config omap1610inn_config TQM855L_config 2108 FPS850L_config omap5912osk_config TQM860L_config 2109 WALNUT405_config 2110 ZPC1900_config 2111 2112Note: for some board special configuration names may exist; check if 2113 additional information is available from the board vendor; for 2114 instance, the TQM823L systems are available without (standard) 2115 or with LCD support. You can select such additional "features" 2116 when chosing the configuration, i. e. 2117 2118 make TQM823L_config 2119 - will configure for a plain TQM823L, i. e. no LCD support 2120 2121 make TQM823L_LCD_config 2122 - will configure for a TQM823L with U-Boot console on LCD 2123 2124 etc. 2125 2126 2127Finally, type "make all", and you should get some working U-Boot 2128images ready for download to / installation on your system: 2129 2130- "u-boot.bin" is a raw binary image 2131- "u-boot" is an image in ELF binary format 2132- "u-boot.srec" is in Motorola S-Record format 2133 2134 2135Please be aware that the Makefiles assume you are using GNU make, so 2136for instance on NetBSD you might need to use "gmake" instead of 2137native "make". 2138 2139 2140If the system board that you have is not listed, then you will need 2141to port U-Boot to your hardware platform. To do this, follow these 2142steps: 2143 21441. Add a new configuration option for your board to the toplevel 2145 "Makefile" and to the "MAKEALL" script, using the existing 2146 entries as examples. Note that here and at many other places 2147 boards and other names are listed in alphabetical sort order. Please 2148 keep this order. 21492. Create a new directory to hold your board specific code. Add any 2150 files you need. In your board directory, you will need at least 2151 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 21523. Create a new configuration file "include/configs/<board>.h" for 2153 your board 21543. If you're porting U-Boot to a new CPU, then also create a new 2155 directory to hold your CPU specific code. Add any files you need. 21564. Run "make <board>_config" with your new name. 21575. Type "make", and you should get a working "u-boot.srec" file 2158 to be installed on your target system. 21596. Debug and solve any problems that might arise. 2160 [Of course, this last step is much harder than it sounds.] 2161 2162 2163Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2164============================================================== 2165 2166If you have modified U-Boot sources (for instance added a new board 2167or support for new devices, a new CPU, etc.) you are expected to 2168provide feedback to the other developers. The feedback normally takes 2169the form of a "patch", i. e. a context diff against a certain (latest 2170official or latest in CVS) version of U-Boot sources. 2171 2172But before you submit such a patch, please verify that your modifi- 2173cation did not break existing code. At least make sure that *ALL* of 2174the supported boards compile WITHOUT ANY compiler warnings. To do so, 2175just run the "MAKEALL" script, which will configure and build U-Boot 2176for ALL supported system. Be warned, this will take a while. You can 2177select which (cross) compiler to use by passing a `CROSS_COMPILE' 2178environment variable to the script, i. e. to use the cross tools from 2179MontaVista's Hard Hat Linux you can type 2180 2181 CROSS_COMPILE=ppc_8xx- MAKEALL 2182 2183or to build on a native PowerPC system you can type 2184 2185 CROSS_COMPILE=' ' MAKEALL 2186 2187See also "U-Boot Porting Guide" below. 2188 2189 2190Monitor Commands - Overview: 2191============================ 2192 2193go - start application at address 'addr' 2194run - run commands in an environment variable 2195bootm - boot application image from memory 2196bootp - boot image via network using BootP/TFTP protocol 2197tftpboot- boot image via network using TFTP protocol 2198 and env variables "ipaddr" and "serverip" 2199 (and eventually "gatewayip") 2200rarpboot- boot image via network using RARP/TFTP protocol 2201diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2202loads - load S-Record file over serial line 2203loadb - load binary file over serial line (kermit mode) 2204md - memory display 2205mm - memory modify (auto-incrementing) 2206nm - memory modify (constant address) 2207mw - memory write (fill) 2208cp - memory copy 2209cmp - memory compare 2210crc32 - checksum calculation 2211imd - i2c memory display 2212imm - i2c memory modify (auto-incrementing) 2213inm - i2c memory modify (constant address) 2214imw - i2c memory write (fill) 2215icrc32 - i2c checksum calculation 2216iprobe - probe to discover valid I2C chip addresses 2217iloop - infinite loop on address range 2218isdram - print SDRAM configuration information 2219sspi - SPI utility commands 2220base - print or set address offset 2221printenv- print environment variables 2222setenv - set environment variables 2223saveenv - save environment variables to persistent storage 2224protect - enable or disable FLASH write protection 2225erase - erase FLASH memory 2226flinfo - print FLASH memory information 2227bdinfo - print Board Info structure 2228iminfo - print header information for application image 2229coninfo - print console devices and informations 2230ide - IDE sub-system 2231loop - infinite loop on address range 2232loopw - infinite write loop on address range 2233mtest - simple RAM test 2234icache - enable or disable instruction cache 2235dcache - enable or disable data cache 2236reset - Perform RESET of the CPU 2237echo - echo args to console 2238version - print monitor version 2239help - print online help 2240? - alias for 'help' 2241 2242 2243Monitor Commands - Detailed Description: 2244======================================== 2245 2246TODO. 2247 2248For now: just type "help <command>". 2249 2250 2251Environment Variables: 2252====================== 2253 2254U-Boot supports user configuration using Environment Variables which 2255can be made persistent by saving to Flash memory. 2256 2257Environment Variables are set using "setenv", printed using 2258"printenv", and saved to Flash using "saveenv". Using "setenv" 2259without a value can be used to delete a variable from the 2260environment. As long as you don't save the environment you are 2261working with an in-memory copy. In case the Flash area containing the 2262environment is erased by accident, a default environment is provided. 2263 2264Some configuration options can be set using Environment Variables: 2265 2266 baudrate - see CONFIG_BAUDRATE 2267 2268 bootdelay - see CONFIG_BOOTDELAY 2269 2270 bootcmd - see CONFIG_BOOTCOMMAND 2271 2272 bootargs - Boot arguments when booting an RTOS image 2273 2274 bootfile - Name of the image to load with TFTP 2275 2276 autoload - if set to "no" (any string beginning with 'n'), 2277 "bootp" will just load perform a lookup of the 2278 configuration from the BOOTP server, but not try to 2279 load any image using TFTP 2280 2281 autostart - if set to "yes", an image loaded using the "bootp", 2282 "rarpboot", "tftpboot" or "diskboot" commands will 2283 be automatically started (by internally calling 2284 "bootm") 2285 2286 If set to "no", a standalone image passed to the 2287 "bootm" command will be copied to the load address 2288 (and eventually uncompressed), but NOT be started. 2289 This can be used to load and uncompress arbitrary 2290 data. 2291 2292 i2cfast - (PPC405GP|PPC405EP only) 2293 if set to 'y' configures Linux I2C driver for fast 2294 mode (400kHZ). This environment variable is used in 2295 initialization code. So, for changes to be effective 2296 it must be saved and board must be reset. 2297 2298 initrd_high - restrict positioning of initrd images: 2299 If this variable is not set, initrd images will be 2300 copied to the highest possible address in RAM; this 2301 is usually what you want since it allows for 2302 maximum initrd size. If for some reason you want to 2303 make sure that the initrd image is loaded below the 2304 CFG_BOOTMAPSZ limit, you can set this environment 2305 variable to a value of "no" or "off" or "0". 2306 Alternatively, you can set it to a maximum upper 2307 address to use (U-Boot will still check that it 2308 does not overwrite the U-Boot stack and data). 2309 2310 For instance, when you have a system with 16 MB 2311 RAM, and want to reserve 4 MB from use by Linux, 2312 you can do this by adding "mem=12M" to the value of 2313 the "bootargs" variable. However, now you must make 2314 sure that the initrd image is placed in the first 2315 12 MB as well - this can be done with 2316 2317 setenv initrd_high 00c00000 2318 2319 If you set initrd_high to 0xFFFFFFFF, this is an 2320 indication to U-Boot that all addresses are legal 2321 for the Linux kernel, including addresses in flash 2322 memory. In this case U-Boot will NOT COPY the 2323 ramdisk at all. This may be useful to reduce the 2324 boot time on your system, but requires that this 2325 feature is supported by your Linux kernel. 2326 2327 ipaddr - IP address; needed for tftpboot command 2328 2329 loadaddr - Default load address for commands like "bootp", 2330 "rarpboot", "tftpboot", "loadb" or "diskboot" 2331 2332 loads_echo - see CONFIG_LOADS_ECHO 2333 2334 serverip - TFTP server IP address; needed for tftpboot command 2335 2336 bootretry - see CONFIG_BOOT_RETRY_TIME 2337 2338 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2339 2340 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2341 2342 ethprime - When CONFIG_NET_MULTI is enabled controls which 2343 interface is used first. 2344 2345 ethact - When CONFIG_NET_MULTI is enabled controls which 2346 interface is currently active. For example you 2347 can do the following 2348 2349 => setenv ethact FEC ETHERNET 2350 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2351 => setenv ethact SCC ETHERNET 2352 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2353 2354 netretry - When set to "no" each network operation will 2355 either succeed or fail without retrying. 2356 When set to "once" the network operation will 2357 fail when all the available network interfaces 2358 are tried once without success. 2359 Useful on scripts which control the retry operation 2360 themselves. 2361 2362 vlan - When set to a value < 4095 the traffic over 2363 ethernet is encapsulated/received over 802.1q 2364 VLAN tagged frames. 2365 2366The following environment variables may be used and automatically 2367updated by the network boot commands ("bootp" and "rarpboot"), 2368depending the information provided by your boot server: 2369 2370 bootfile - see above 2371 dnsip - IP address of your Domain Name Server 2372 dnsip2 - IP address of your secondary Domain Name Server 2373 gatewayip - IP address of the Gateway (Router) to use 2374 hostname - Target hostname 2375 ipaddr - see above 2376 netmask - Subnet Mask 2377 rootpath - Pathname of the root filesystem on the NFS server 2378 serverip - see above 2379 2380 2381There are two special Environment Variables: 2382 2383 serial# - contains hardware identification information such 2384 as type string and/or serial number 2385 ethaddr - Ethernet address 2386 2387These variables can be set only once (usually during manufacturing of 2388the board). U-Boot refuses to delete or overwrite these variables 2389once they have been set once. 2390 2391 2392Further special Environment Variables: 2393 2394 ver - Contains the U-Boot version string as printed 2395 with the "version" command. This variable is 2396 readonly (see CONFIG_VERSION_VARIABLE). 2397 2398 2399Please note that changes to some configuration parameters may take 2400only effect after the next boot (yes, that's just like Windoze :-). 2401 2402 2403Command Line Parsing: 2404===================== 2405 2406There are two different command line parsers available with U-Boot: 2407the old "simple" one, and the much more powerful "hush" shell: 2408 2409Old, simple command line parser: 2410-------------------------------- 2411 2412- supports environment variables (through setenv / saveenv commands) 2413- several commands on one line, separated by ';' 2414- variable substitution using "... $(name) ..." syntax 2415- special characters ('$', ';') can be escaped by prefixing with '\', 2416 for example: 2417 setenv bootcmd bootm \$(address) 2418- You can also escape text by enclosing in single apostrophes, for example: 2419 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2420 2421Hush shell: 2422----------- 2423 2424- similar to Bourne shell, with control structures like 2425 if...then...else...fi, for...do...done; while...do...done, 2426 until...do...done, ... 2427- supports environment ("global") variables (through setenv / saveenv 2428 commands) and local shell variables (through standard shell syntax 2429 "name=value"); only environment variables can be used with "run" 2430 command 2431 2432General rules: 2433-------------- 2434 2435(1) If a command line (or an environment variable executed by a "run" 2436 command) contains several commands separated by semicolon, and 2437 one of these commands fails, then the remaining commands will be 2438 executed anyway. 2439 2440(2) If you execute several variables with one call to run (i. e. 2441 calling run with a list af variables as arguments), any failing 2442 command will cause "run" to terminate, i. e. the remaining 2443 variables are not executed. 2444 2445Note for Redundant Ethernet Interfaces: 2446======================================= 2447 2448Some boards come with redundant ethernet interfaces; U-Boot supports 2449such configurations and is capable of automatic selection of a 2450"working" interface when needed. MAC assignment works as follows: 2451 2452Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2453MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2454"eth1addr" (=>eth1), "eth2addr", ... 2455 2456If the network interface stores some valid MAC address (for instance 2457in SROM), this is used as default address if there is NO correspon- 2458ding setting in the environment; if the corresponding environment 2459variable is set, this overrides the settings in the card; that means: 2460 2461o If the SROM has a valid MAC address, and there is no address in the 2462 environment, the SROM's address is used. 2463 2464o If there is no valid address in the SROM, and a definition in the 2465 environment exists, then the value from the environment variable is 2466 used. 2467 2468o If both the SROM and the environment contain a MAC address, and 2469 both addresses are the same, this MAC address is used. 2470 2471o If both the SROM and the environment contain a MAC address, and the 2472 addresses differ, the value from the environment is used and a 2473 warning is printed. 2474 2475o If neither SROM nor the environment contain a MAC address, an error 2476 is raised. 2477 2478 2479Image Formats: 2480============== 2481 2482The "boot" commands of this monitor operate on "image" files which 2483can be basicly anything, preceeded by a special header; see the 2484definitions in include/image.h for details; basicly, the header 2485defines the following image properties: 2486 2487* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2488 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2489 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2490 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2491* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2492 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2493 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC). 2494* Compression Type (uncompressed, gzip, bzip2) 2495* Load Address 2496* Entry Point 2497* Image Name 2498* Image Timestamp 2499 2500The header is marked by a special Magic Number, and both the header 2501and the data portions of the image are secured against corruption by 2502CRC32 checksums. 2503 2504 2505Linux Support: 2506============== 2507 2508Although U-Boot should support any OS or standalone application 2509easily, the main focus has always been on Linux during the design of 2510U-Boot. 2511 2512U-Boot includes many features that so far have been part of some 2513special "boot loader" code within the Linux kernel. Also, any 2514"initrd" images to be used are no longer part of one big Linux image; 2515instead, kernel and "initrd" are separate images. This implementation 2516serves several purposes: 2517 2518- the same features can be used for other OS or standalone 2519 applications (for instance: using compressed images to reduce the 2520 Flash memory footprint) 2521 2522- it becomes much easier to port new Linux kernel versions because 2523 lots of low-level, hardware dependent stuff are done by U-Boot 2524 2525- the same Linux kernel image can now be used with different "initrd" 2526 images; of course this also means that different kernel images can 2527 be run with the same "initrd". This makes testing easier (you don't 2528 have to build a new "zImage.initrd" Linux image when you just 2529 change a file in your "initrd"). Also, a field-upgrade of the 2530 software is easier now. 2531 2532 2533Linux HOWTO: 2534============ 2535 2536Porting Linux to U-Boot based systems: 2537--------------------------------------- 2538 2539U-Boot cannot save you from doing all the necessary modifications to 2540configure the Linux device drivers for use with your target hardware 2541(no, we don't intend to provide a full virtual machine interface to 2542Linux :-). 2543 2544But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2545 2546Just make sure your machine specific header file (for instance 2547include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2548Information structure as we define in include/u-boot.h, and make 2549sure that your definition of IMAP_ADDR uses the same value as your 2550U-Boot configuration in CFG_IMMR. 2551 2552 2553Configuring the Linux kernel: 2554----------------------------- 2555 2556No specific requirements for U-Boot. Make sure you have some root 2557device (initial ramdisk, NFS) for your target system. 2558 2559 2560Building a Linux Image: 2561----------------------- 2562 2563With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2564not used. If you use recent kernel source, a new build target 2565"uImage" will exist which automatically builds an image usable by 2566U-Boot. Most older kernels also have support for a "pImage" target, 2567which was introduced for our predecessor project PPCBoot and uses a 2568100% compatible format. 2569 2570Example: 2571 2572 make TQM850L_config 2573 make oldconfig 2574 make dep 2575 make uImage 2576 2577The "uImage" build target uses a special tool (in 'tools/mkimage') to 2578encapsulate a compressed Linux kernel image with header information, 2579CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2580 2581* build a standard "vmlinux" kernel image (in ELF binary format): 2582 2583* convert the kernel into a raw binary image: 2584 2585 ${CROSS_COMPILE}-objcopy -O binary \ 2586 -R .note -R .comment \ 2587 -S vmlinux linux.bin 2588 2589* compress the binary image: 2590 2591 gzip -9 linux.bin 2592 2593* package compressed binary image for U-Boot: 2594 2595 mkimage -A ppc -O linux -T kernel -C gzip \ 2596 -a 0 -e 0 -n "Linux Kernel Image" \ 2597 -d linux.bin.gz uImage 2598 2599 2600The "mkimage" tool can also be used to create ramdisk images for use 2601with U-Boot, either separated from the Linux kernel image, or 2602combined into one file. "mkimage" encapsulates the images with a 64 2603byte header containing information about target architecture, 2604operating system, image type, compression method, entry points, time 2605stamp, CRC32 checksums, etc. 2606 2607"mkimage" can be called in two ways: to verify existing images and 2608print the header information, or to build new images. 2609 2610In the first form (with "-l" option) mkimage lists the information 2611contained in the header of an existing U-Boot image; this includes 2612checksum verification: 2613 2614 tools/mkimage -l image 2615 -l ==> list image header information 2616 2617The second form (with "-d" option) is used to build a U-Boot image 2618from a "data file" which is used as image payload: 2619 2620 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2621 -n name -d data_file image 2622 -A ==> set architecture to 'arch' 2623 -O ==> set operating system to 'os' 2624 -T ==> set image type to 'type' 2625 -C ==> set compression type 'comp' 2626 -a ==> set load address to 'addr' (hex) 2627 -e ==> set entry point to 'ep' (hex) 2628 -n ==> set image name to 'name' 2629 -d ==> use image data from 'datafile' 2630 2631Right now, all Linux kernels for PowerPC systems use the same load 2632address (0x00000000), but the entry point address depends on the 2633kernel version: 2634 2635- 2.2.x kernels have the entry point at 0x0000000C, 2636- 2.3.x and later kernels have the entry point at 0x00000000. 2637 2638So a typical call to build a U-Boot image would read: 2639 2640 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2641 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2642 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2643 > examples/uImage.TQM850L 2644 Image Name: 2.4.4 kernel for TQM850L 2645 Created: Wed Jul 19 02:34:59 2000 2646 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2647 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2648 Load Address: 0x00000000 2649 Entry Point: 0x00000000 2650 2651To verify the contents of the image (or check for corruption): 2652 2653 -> tools/mkimage -l examples/uImage.TQM850L 2654 Image Name: 2.4.4 kernel for TQM850L 2655 Created: Wed Jul 19 02:34:59 2000 2656 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2657 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2658 Load Address: 0x00000000 2659 Entry Point: 0x00000000 2660 2661NOTE: for embedded systems where boot time is critical you can trade 2662speed for memory and install an UNCOMPRESSED image instead: this 2663needs more space in Flash, but boots much faster since it does not 2664need to be uncompressed: 2665 2666 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2667 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2668 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2669 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2670 > examples/uImage.TQM850L-uncompressed 2671 Image Name: 2.4.4 kernel for TQM850L 2672 Created: Wed Jul 19 02:34:59 2000 2673 Image Type: PowerPC Linux Kernel Image (uncompressed) 2674 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2675 Load Address: 0x00000000 2676 Entry Point: 0x00000000 2677 2678 2679Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2680when your kernel is intended to use an initial ramdisk: 2681 2682 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2683 > -A ppc -O linux -T ramdisk -C gzip \ 2684 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2685 Image Name: Simple Ramdisk Image 2686 Created: Wed Jan 12 14:01:50 2000 2687 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2688 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2689 Load Address: 0x00000000 2690 Entry Point: 0x00000000 2691 2692 2693Installing a Linux Image: 2694------------------------- 2695 2696To downloading a U-Boot image over the serial (console) interface, 2697you must convert the image to S-Record format: 2698 2699 objcopy -I binary -O srec examples/image examples/image.srec 2700 2701The 'objcopy' does not understand the information in the U-Boot 2702image header, so the resulting S-Record file will be relative to 2703address 0x00000000. To load it to a given address, you need to 2704specify the target address as 'offset' parameter with the 'loads' 2705command. 2706 2707Example: install the image to address 0x40100000 (which on the 2708TQM8xxL is in the first Flash bank): 2709 2710 => erase 40100000 401FFFFF 2711 2712 .......... done 2713 Erased 8 sectors 2714 2715 => loads 40100000 2716 ## Ready for S-Record download ... 2717 ~>examples/image.srec 2718 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2719 ... 2720 15989 15990 15991 15992 2721 [file transfer complete] 2722 [connected] 2723 ## Start Addr = 0x00000000 2724 2725 2726You can check the success of the download using the 'iminfo' command; 2727this includes a checksum verification so you can be sure no data 2728corruption happened: 2729 2730 => imi 40100000 2731 2732 ## Checking Image at 40100000 ... 2733 Image Name: 2.2.13 for initrd on TQM850L 2734 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2735 Data Size: 335725 Bytes = 327 kB = 0 MB 2736 Load Address: 00000000 2737 Entry Point: 0000000c 2738 Verifying Checksum ... OK 2739 2740 2741Boot Linux: 2742----------- 2743 2744The "bootm" command is used to boot an application that is stored in 2745memory (RAM or Flash). In case of a Linux kernel image, the contents 2746of the "bootargs" environment variable is passed to the kernel as 2747parameters. You can check and modify this variable using the 2748"printenv" and "setenv" commands: 2749 2750 2751 => printenv bootargs 2752 bootargs=root=/dev/ram 2753 2754 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2755 2756 => printenv bootargs 2757 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2758 2759 => bootm 40020000 2760 ## Booting Linux kernel at 40020000 ... 2761 Image Name: 2.2.13 for NFS on TQM850L 2762 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2763 Data Size: 381681 Bytes = 372 kB = 0 MB 2764 Load Address: 00000000 2765 Entry Point: 0000000c 2766 Verifying Checksum ... OK 2767 Uncompressing Kernel Image ... OK 2768 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 2769 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2770 time_init: decrementer frequency = 187500000/60 2771 Calibrating delay loop... 49.77 BogoMIPS 2772 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2773 ... 2774 2775If you want to boot a Linux kernel with initial ram disk, you pass 2776the memory addresses of both the kernel and the initrd image (PPBCOOT 2777format!) to the "bootm" command: 2778 2779 => imi 40100000 40200000 2780 2781 ## Checking Image at 40100000 ... 2782 Image Name: 2.2.13 for initrd on TQM850L 2783 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2784 Data Size: 335725 Bytes = 327 kB = 0 MB 2785 Load Address: 00000000 2786 Entry Point: 0000000c 2787 Verifying Checksum ... OK 2788 2789 ## Checking Image at 40200000 ... 2790 Image Name: Simple Ramdisk Image 2791 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2792 Data Size: 566530 Bytes = 553 kB = 0 MB 2793 Load Address: 00000000 2794 Entry Point: 00000000 2795 Verifying Checksum ... OK 2796 2797 => bootm 40100000 40200000 2798 ## Booting Linux kernel at 40100000 ... 2799 Image Name: 2.2.13 for initrd on TQM850L 2800 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2801 Data Size: 335725 Bytes = 327 kB = 0 MB 2802 Load Address: 00000000 2803 Entry Point: 0000000c 2804 Verifying Checksum ... OK 2805 Uncompressing Kernel Image ... OK 2806 ## Loading RAMDisk Image at 40200000 ... 2807 Image Name: Simple Ramdisk Image 2808 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2809 Data Size: 566530 Bytes = 553 kB = 0 MB 2810 Load Address: 00000000 2811 Entry Point: 00000000 2812 Verifying Checksum ... OK 2813 Loading Ramdisk ... OK 2814 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 2815 Boot arguments: root=/dev/ram 2816 time_init: decrementer frequency = 187500000/60 2817 Calibrating delay loop... 49.77 BogoMIPS 2818 ... 2819 RAMDISK: Compressed image found at block 0 2820 VFS: Mounted root (ext2 filesystem). 2821 2822 bash# 2823 2824More About U-Boot Image Types: 2825------------------------------ 2826 2827U-Boot supports the following image types: 2828 2829 "Standalone Programs" are directly runnable in the environment 2830 provided by U-Boot; it is expected that (if they behave 2831 well) you can continue to work in U-Boot after return from 2832 the Standalone Program. 2833 "OS Kernel Images" are usually images of some Embedded OS which 2834 will take over control completely. Usually these programs 2835 will install their own set of exception handlers, device 2836 drivers, set up the MMU, etc. - this means, that you cannot 2837 expect to re-enter U-Boot except by resetting the CPU. 2838 "RAMDisk Images" are more or less just data blocks, and their 2839 parameters (address, size) are passed to an OS kernel that is 2840 being started. 2841 "Multi-File Images" contain several images, typically an OS 2842 (Linux) kernel image and one or more data images like 2843 RAMDisks. This construct is useful for instance when you want 2844 to boot over the network using BOOTP etc., where the boot 2845 server provides just a single image file, but you want to get 2846 for instance an OS kernel and a RAMDisk image. 2847 2848 "Multi-File Images" start with a list of image sizes, each 2849 image size (in bytes) specified by an "uint32_t" in network 2850 byte order. This list is terminated by an "(uint32_t)0". 2851 Immediately after the terminating 0 follow the images, one by 2852 one, all aligned on "uint32_t" boundaries (size rounded up to 2853 a multiple of 4 bytes). 2854 2855 "Firmware Images" are binary images containing firmware (like 2856 U-Boot or FPGA images) which usually will be programmed to 2857 flash memory. 2858 2859 "Script files" are command sequences that will be executed by 2860 U-Boot's command interpreter; this feature is especially 2861 useful when you configure U-Boot to use a real shell (hush) 2862 as command interpreter. 2863 2864 2865Standalone HOWTO: 2866================= 2867 2868One of the features of U-Boot is that you can dynamically load and 2869run "standalone" applications, which can use some resources of 2870U-Boot like console I/O functions or interrupt services. 2871 2872Two simple examples are included with the sources: 2873 2874"Hello World" Demo: 2875------------------- 2876 2877'examples/hello_world.c' contains a small "Hello World" Demo 2878application; it is automatically compiled when you build U-Boot. 2879It's configured to run at address 0x00040004, so you can play with it 2880like that: 2881 2882 => loads 2883 ## Ready for S-Record download ... 2884 ~>examples/hello_world.srec 2885 1 2 3 4 5 6 7 8 9 10 11 ... 2886 [file transfer complete] 2887 [connected] 2888 ## Start Addr = 0x00040004 2889 2890 => go 40004 Hello World! This is a test. 2891 ## Starting application at 0x00040004 ... 2892 Hello World 2893 argc = 7 2894 argv[0] = "40004" 2895 argv[1] = "Hello" 2896 argv[2] = "World!" 2897 argv[3] = "This" 2898 argv[4] = "is" 2899 argv[5] = "a" 2900 argv[6] = "test." 2901 argv[7] = "<NULL>" 2902 Hit any key to exit ... 2903 2904 ## Application terminated, rc = 0x0 2905 2906Another example, which demonstrates how to register a CPM interrupt 2907handler with the U-Boot code, can be found in 'examples/timer.c'. 2908Here, a CPM timer is set up to generate an interrupt every second. 2909The interrupt service routine is trivial, just printing a '.' 2910character, but this is just a demo program. The application can be 2911controlled by the following keys: 2912 2913 ? - print current values og the CPM Timer registers 2914 b - enable interrupts and start timer 2915 e - stop timer and disable interrupts 2916 q - quit application 2917 2918 => loads 2919 ## Ready for S-Record download ... 2920 ~>examples/timer.srec 2921 1 2 3 4 5 6 7 8 9 10 11 ... 2922 [file transfer complete] 2923 [connected] 2924 ## Start Addr = 0x00040004 2925 2926 => go 40004 2927 ## Starting application at 0x00040004 ... 2928 TIMERS=0xfff00980 2929 Using timer 1 2930 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2931 2932Hit 'b': 2933 [q, b, e, ?] Set interval 1000000 us 2934 Enabling timer 2935Hit '?': 2936 [q, b, e, ?] ........ 2937 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2938Hit '?': 2939 [q, b, e, ?] . 2940 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2941Hit '?': 2942 [q, b, e, ?] . 2943 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2944Hit '?': 2945 [q, b, e, ?] . 2946 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2947Hit 'e': 2948 [q, b, e, ?] ...Stopping timer 2949Hit 'q': 2950 [q, b, e, ?] ## Application terminated, rc = 0x0 2951 2952 2953Minicom warning: 2954================ 2955 2956Over time, many people have reported problems when trying to use the 2957"minicom" terminal emulation program for serial download. I (wd) 2958consider minicom to be broken, and recommend not to use it. Under 2959Unix, I recommend to use C-Kermit for general purpose use (and 2960especially for kermit binary protocol download ("loadb" command), and 2961use "cu" for S-Record download ("loads" command). 2962 2963Nevertheless, if you absolutely want to use it try adding this 2964configuration to your "File transfer protocols" section: 2965 2966 Name Program Name U/D FullScr IO-Red. Multi 2967 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2968 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2969 2970 2971NetBSD Notes: 2972============= 2973 2974Starting at version 0.9.2, U-Boot supports NetBSD both as host 2975(build U-Boot) and target system (boots NetBSD/mpc8xx). 2976 2977Building requires a cross environment; it is known to work on 2978NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2979need gmake since the Makefiles are not compatible with BSD make). 2980Note that the cross-powerpc package does not install include files; 2981attempting to build U-Boot will fail because <machine/ansi.h> is 2982missing. This file has to be installed and patched manually: 2983 2984 # cd /usr/pkg/cross/powerpc-netbsd/include 2985 # mkdir powerpc 2986 # ln -s powerpc machine 2987 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2988 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2989 2990Native builds *don't* work due to incompatibilities between native 2991and U-Boot include files. 2992 2993Booting assumes that (the first part of) the image booted is a 2994stage-2 loader which in turn loads and then invokes the kernel 2995proper. Loader sources will eventually appear in the NetBSD source 2996tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2997meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2998details. 2999 3000 3001Implementation Internals: 3002========================= 3003 3004The following is not intended to be a complete description of every 3005implementation detail. However, it should help to understand the 3006inner workings of U-Boot and make it easier to port it to custom 3007hardware. 3008 3009 3010Initial Stack, Global Data: 3011--------------------------- 3012 3013The implementation of U-Boot is complicated by the fact that U-Boot 3014starts running out of ROM (flash memory), usually without access to 3015system RAM (because the memory controller is not initialized yet). 3016This means that we don't have writable Data or BSS segments, and BSS 3017is not initialized as zero. To be able to get a C environment working 3018at all, we have to allocate at least a minimal stack. Implementation 3019options for this are defined and restricted by the CPU used: Some CPU 3020models provide on-chip memory (like the IMMR area on MPC8xx and 3021MPC826x processors), on others (parts of) the data cache can be 3022locked as (mis-) used as memory, etc. 3023 3024 Chris Hallinan posted a good summary of these issues to the 3025 u-boot-users mailing list: 3026 3027 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 3028 From: "Chris Hallinan" <clh@net1plus.com> 3029 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 3030 ... 3031 3032 Correct me if I'm wrong, folks, but the way I understand it 3033 is this: Using DCACHE as initial RAM for Stack, etc, does not 3034 require any physical RAM backing up the cache. The cleverness 3035 is that the cache is being used as a temporary supply of 3036 necessary storage before the SDRAM controller is setup. It's 3037 beyond the scope of this list to expain the details, but you 3038 can see how this works by studying the cache architecture and 3039 operation in the architecture and processor-specific manuals. 3040 3041 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3042 is another option for the system designer to use as an 3043 initial stack/ram area prior to SDRAM being available. Either 3044 option should work for you. Using CS 4 should be fine if your 3045 board designers haven't used it for something that would 3046 cause you grief during the initial boot! It is frequently not 3047 used. 3048 3049 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3050 with your processor/board/system design. The default value 3051 you will find in any recent u-boot distribution in 3052 Walnut405.h should work for you. I'd set it to a value larger 3053 than your SDRAM module. If you have a 64MB SDRAM module, set 3054 it above 400_0000. Just make sure your board has no resources 3055 that are supposed to respond to that address! That code in 3056 start.S has been around a while and should work as is when 3057 you get the config right. 3058 3059 -Chris Hallinan 3060 DS4.COM, Inc. 3061 3062It is essential to remember this, since it has some impact on the C 3063code for the initialization procedures: 3064 3065* Initialized global data (data segment) is read-only. Do not attempt 3066 to write it. 3067 3068* Do not use any unitialized global data (or implicitely initialized 3069 as zero data - BSS segment) at all - this is undefined, initiali- 3070 zation is performed later (when relocating to RAM). 3071 3072* Stack space is very limited. Avoid big data buffers or things like 3073 that. 3074 3075Having only the stack as writable memory limits means we cannot use 3076normal global data to share information beween the code. But it 3077turned out that the implementation of U-Boot can be greatly 3078simplified by making a global data structure (gd_t) available to all 3079functions. We could pass a pointer to this data as argument to _all_ 3080functions, but this would bloat the code. Instead we use a feature of 3081the GCC compiler (Global Register Variables) to share the data: we 3082place a pointer (gd) to the global data into a register which we 3083reserve for this purpose. 3084 3085When choosing a register for such a purpose we are restricted by the 3086relevant (E)ABI specifications for the current architecture, and by 3087GCC's implementation. 3088 3089For PowerPC, the following registers have specific use: 3090 R1: stack pointer 3091 R2: TOC pointer 3092 R3-R4: parameter passing and return values 3093 R5-R10: parameter passing 3094 R13: small data area pointer 3095 R30: GOT pointer 3096 R31: frame pointer 3097 3098 (U-Boot also uses R14 as internal GOT pointer.) 3099 3100 ==> U-Boot will use R29 to hold a pointer to the global data 3101 3102 Note: on PPC, we could use a static initializer (since the 3103 address of the global data structure is known at compile time), 3104 but it turned out that reserving a register results in somewhat 3105 smaller code - although the code savings are not that big (on 3106 average for all boards 752 bytes for the whole U-Boot image, 3107 624 text + 127 data). 3108 3109On ARM, the following registers are used: 3110 3111 R0: function argument word/integer result 3112 R1-R3: function argument word 3113 R9: GOT pointer 3114 R10: stack limit (used only if stack checking if enabled) 3115 R11: argument (frame) pointer 3116 R12: temporary workspace 3117 R13: stack pointer 3118 R14: link register 3119 R15: program counter 3120 3121 ==> U-Boot will use R8 to hold a pointer to the global data 3122 3123 3124Memory Management: 3125------------------ 3126 3127U-Boot runs in system state and uses physical addresses, i.e. the 3128MMU is not used either for address mapping nor for memory protection. 3129 3130The available memory is mapped to fixed addresses using the memory 3131controller. In this process, a contiguous block is formed for each 3132memory type (Flash, SDRAM, SRAM), even when it consists of several 3133physical memory banks. 3134 3135U-Boot is installed in the first 128 kB of the first Flash bank (on 3136TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3137booting and sizing and initializing DRAM, the code relocates itself 3138to the upper end of DRAM. Immediately below the U-Boot code some 3139memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3140configuration setting]. Below that, a structure with global Board 3141Info data is placed, followed by the stack (growing downward). 3142 3143Additionally, some exception handler code is copied to the low 8 kB 3144of DRAM (0x00000000 ... 0x00001FFF). 3145 3146So a typical memory configuration with 16 MB of DRAM could look like 3147this: 3148 3149 0x0000 0000 Exception Vector code 3150 : 3151 0x0000 1FFF 3152 0x0000 2000 Free for Application Use 3153 : 3154 : 3155 3156 : 3157 : 3158 0x00FB FF20 Monitor Stack (Growing downward) 3159 0x00FB FFAC Board Info Data and permanent copy of global data 3160 0x00FC 0000 Malloc Arena 3161 : 3162 0x00FD FFFF 3163 0x00FE 0000 RAM Copy of Monitor Code 3164 ... eventually: LCD or video framebuffer 3165 ... eventually: pRAM (Protected RAM - unchanged by reset) 3166 0x00FF FFFF [End of RAM] 3167 3168 3169System Initialization: 3170---------------------- 3171 3172In the reset configuration, U-Boot starts at the reset entry point 3173(on most PowerPC systens at address 0x00000100). Because of the reset 3174configuration for CS0# this is a mirror of the onboard Flash memory. 3175To be able to re-map memory U-Boot then jumps to its link address. 3176To be able to implement the initialization code in C, a (small!) 3177initial stack is set up in the internal Dual Ported RAM (in case CPUs 3178which provide such a feature like MPC8xx or MPC8260), or in a locked 3179part of the data cache. After that, U-Boot initializes the CPU core, 3180the caches and the SIU. 3181 3182Next, all (potentially) available memory banks are mapped using a 3183preliminary mapping. For example, we put them on 512 MB boundaries 3184(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3185on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3186programmed for SDRAM access. Using the temporary configuration, a 3187simple memory test is run that determines the size of the SDRAM 3188banks. 3189 3190When there is more than one SDRAM bank, and the banks are of 3191different size, the largest is mapped first. For equal size, the first 3192bank (CS2#) is mapped first. The first mapping is always for address 31930x00000000, with any additional banks following immediately to create 3194contiguous memory starting from 0. 3195 3196Then, the monitor installs itself at the upper end of the SDRAM area 3197and allocates memory for use by malloc() and for the global Board 3198Info data; also, the exception vector code is copied to the low RAM 3199pages, and the final stack is set up. 3200 3201Only after this relocation will you have a "normal" C environment; 3202until that you are restricted in several ways, mostly because you are 3203running from ROM, and because the code will have to be relocated to a 3204new address in RAM. 3205 3206 3207U-Boot Porting Guide: 3208---------------------- 3209 3210[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3211list, October 2002] 3212 3213 3214int main (int argc, char *argv[]) 3215{ 3216 sighandler_t no_more_time; 3217 3218 signal (SIGALRM, no_more_time); 3219 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3220 3221 if (available_money > available_manpower) { 3222 pay consultant to port U-Boot; 3223 return 0; 3224 } 3225 3226 Download latest U-Boot source; 3227 3228 Subscribe to u-boot-users mailing list; 3229 3230 if (clueless) { 3231 email ("Hi, I am new to U-Boot, how do I get started?"); 3232 } 3233 3234 while (learning) { 3235 Read the README file in the top level directory; 3236 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3237 Read the source, Luke; 3238 } 3239 3240 if (available_money > toLocalCurrency ($2500)) { 3241 Buy a BDI2000; 3242 } else { 3243 Add a lot of aggravation and time; 3244 } 3245 3246 Create your own board support subdirectory; 3247 3248 Create your own board config file; 3249 3250 while (!running) { 3251 do { 3252 Add / modify source code; 3253 } until (compiles); 3254 Debug; 3255 if (clueless) 3256 email ("Hi, I am having problems..."); 3257 } 3258 Send patch file to Wolfgang; 3259 3260 return 0; 3261} 3262 3263void no_more_time (int sig) 3264{ 3265 hire_a_guru(); 3266} 3267 3268 3269Coding Standards: 3270----------------- 3271 3272All contributions to U-Boot should conform to the Linux kernel 3273coding style; see the file "Documentation/CodingStyle" in your Linux 3274kernel source directory. 3275 3276Please note that U-Boot is implemented in C (and to some small parts 3277in Assembler); no C++ is used, so please do not use C++ style 3278comments (//) in your code. 3279 3280Please also stick to the following formatting rules: 3281- remove any trailing white space 3282- use TAB characters for indentation, not spaces 3283- make sure NOT to use DOS '\r\n' line feeds 3284- do not add more than 2 empty lines to source files 3285- do not add trailing empty lines to source files 3286 3287Submissions which do not conform to the standards may be returned 3288with a request to reformat the changes. 3289 3290 3291Submitting Patches: 3292------------------- 3293 3294Since the number of patches for U-Boot is growing, we need to 3295establish some rules. Submissions which do not conform to these rules 3296may be rejected, even when they contain important and valuable stuff. 3297 3298 3299When you send a patch, please include the following information with 3300it: 3301 3302* For bug fixes: a description of the bug and how your patch fixes 3303 this bug. Please try to include a way of demonstrating that the 3304 patch actually fixes something. 3305 3306* For new features: a description of the feature and your 3307 implementation. 3308 3309* A CHANGELOG entry as plaintext (separate from the patch) 3310 3311* For major contributions, your entry to the CREDITS file 3312 3313* When you add support for a new board, don't forget to add this 3314 board to the MAKEALL script, too. 3315 3316* If your patch adds new configuration options, don't forget to 3317 document these in the README file. 3318 3319* The patch itself. If you are accessing the CVS repository use "cvs 3320 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3321 version of diff does not support these options, then get the latest 3322 version of GNU diff. 3323 3324 The current directory when running this command shall be the top 3325 level directory of the U-Boot source tree, or it's parent directory 3326 (i. e. please make sure that your patch includes sufficient 3327 directory information for the affected files). 3328 3329 We accept patches as plain text, MIME attachments or as uuencoded 3330 gzipped text. 3331 3332* If one logical set of modifications affects or creates several 3333 files, all these changes shall be submitted in a SINGLE patch file. 3334 3335* Changesets that contain different, unrelated modifications shall be 3336 submitted as SEPARATE patches, one patch per changeset. 3337 3338 3339Notes: 3340 3341* Before sending the patch, run the MAKEALL script on your patched 3342 source tree and make sure that no errors or warnings are reported 3343 for any of the boards. 3344 3345* Keep your modifications to the necessary minimum: A patch 3346 containing several unrelated changes or arbitrary reformats will be 3347 returned with a request to re-formatting / split it. 3348 3349* If you modify existing code, make sure that your new code does not 3350 add to the memory footprint of the code ;-) Small is beautiful! 3351 When adding new features, these should compile conditionally only 3352 (using #ifdef), and the resulting code with the new feature 3353 disabled must not need more memory than the old code without your 3354 modification. 3355