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_DNP1110, CONFIG_EP7312, 295 CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE, CONFIG_IMPA7, 296 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610, CONFIG_LART, 297 CONFIG_LPD7A400 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, 298 CONFIG_SHANNON, CONFIG_P2_OMAP730, CONFIG_SMDK2400, 299 CONFIG_SMDK2410, CONFIG_TRAB, CONFIG_VCMA9 300 301 MicroBlaze based boards: 302 ------------------------ 303 304 CONFIG_SUZAKU 305 306 307- CPU Module Type: (if CONFIG_COGENT is defined) 308 Define exactly one of 309 CONFIG_CMA286_60_OLD 310--- FIXME --- not tested yet: 311 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 312 CONFIG_CMA287_23, CONFIG_CMA287_50 313 314- Motherboard Type: (if CONFIG_COGENT is defined) 315 Define exactly one of 316 CONFIG_CMA101, CONFIG_CMA102 317 318- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 319 Define one or more of 320 CONFIG_CMA302 321 322- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 323 Define one or more of 324 CONFIG_LCD_HEARTBEAT - update a character position on 325 the lcd display every second with 326 a "rotator" |\-/|\-/ 327 328- Board flavour: (if CONFIG_MPC8260ADS is defined) 329 CONFIG_ADSTYPE 330 Possible values are: 331 CFG_8260ADS - original MPC8260ADS 332 CFG_8266ADS - MPC8266ADS 333 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR 334 CFG_8272ADS - MPC8272ADS 335 336- MPC824X Family Member (if CONFIG_MPC824X is defined) 337 Define exactly one of 338 CONFIG_MPC8240, CONFIG_MPC8245 339 340- 8xx CPU Options: (if using an MPC8xx cpu) 341 Define one or more of 342 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work 343 e.g. if there is no 32KHz 344 reference PIT/RTC clock 345 346- 859/866 CPU options: (if using a MPC859 or MPC866 CPU): 347 CFG_866_OSCCLK 348 CFG_866_CPUCLK_MIN 349 CFG_866_CPUCLK_MAX 350 CFG_866_CPUCLK_DEFAULT 351 See doc/README.MPC866 352 353 CFG_MEASURE_CPUCLK 354 355 Define this to measure the actual CPU clock instead 356 of relying on the correctness of the configured 357 values. Mostly useful for board bringup to make sure 358 the PLL is locked at the intended frequency. Note 359 that this requires a (stable) reference clock (32 kHz 360 RTC clock), 361 362- Linux Kernel Interface: 363 CONFIG_CLOCKS_IN_MHZ 364 365 U-Boot stores all clock information in Hz 366 internally. For binary compatibility with older Linux 367 kernels (which expect the clocks passed in the 368 bd_info data to be in MHz) the environment variable 369 "clocks_in_mhz" can be defined so that U-Boot 370 converts clock data to MHZ before passing it to the 371 Linux kernel. 372 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 373 "clocks_in_mhz=1" is automatically included in the 374 default environment. 375 376 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 377 378 When transfering memsize parameter to linux, some versions 379 expect it to be in bytes, others in MB. 380 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 381 382- Console Interface: 383 Depending on board, define exactly one serial port 384 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 385 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 386 console by defining CONFIG_8xx_CONS_NONE 387 388 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 389 port routines must be defined elsewhere 390 (i.e. serial_init(), serial_getc(), ...) 391 392 CONFIG_CFB_CONSOLE 393 Enables console device for a color framebuffer. Needs following 394 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 395 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 396 (default big endian) 397 VIDEO_HW_RECTFILL graphic chip supports 398 rectangle fill 399 (cf. smiLynxEM) 400 VIDEO_HW_BITBLT graphic chip supports 401 bit-blit (cf. smiLynxEM) 402 VIDEO_VISIBLE_COLS visible pixel columns 403 (cols=pitch) 404 VIDEO_VISIBLE_ROWS visible pixel rows 405 VIDEO_PIXEL_SIZE bytes per pixel 406 VIDEO_DATA_FORMAT graphic data format 407 (0-5, cf. cfb_console.c) 408 VIDEO_FB_ADRS framebuffer address 409 VIDEO_KBD_INIT_FCT keyboard int fct 410 (i.e. i8042_kbd_init()) 411 VIDEO_TSTC_FCT test char fct 412 (i.e. i8042_tstc) 413 VIDEO_GETC_FCT get char fct 414 (i.e. i8042_getc) 415 CONFIG_CONSOLE_CURSOR cursor drawing on/off 416 (requires blink timer 417 cf. i8042.c) 418 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 419 CONFIG_CONSOLE_TIME display time/date info in 420 upper right corner 421 (requires CFG_CMD_DATE) 422 CONFIG_VIDEO_LOGO display Linux logo in 423 upper left corner 424 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 425 linux_logo.h for logo. 426 Requires CONFIG_VIDEO_LOGO 427 CONFIG_CONSOLE_EXTRA_INFO 428 addional board info beside 429 the logo 430 431 When CONFIG_CFB_CONSOLE is defined, video console is 432 default i/o. Serial console can be forced with 433 environment 'console=serial'. 434 435 When CONFIG_SILENT_CONSOLE is defined, all console 436 messages (by U-Boot and Linux!) can be silenced with 437 the "silent" environment variable. See 438 doc/README.silent for more information. 439 440- Console Baudrate: 441 CONFIG_BAUDRATE - in bps 442 Select one of the baudrates listed in 443 CFG_BAUDRATE_TABLE, see below. 444 CFG_BRGCLK_PRESCALE, baudrate prescale 445 446- Interrupt driven serial port input: 447 CONFIG_SERIAL_SOFTWARE_FIFO 448 449 PPC405GP only. 450 Use an interrupt handler for receiving data on the 451 serial port. It also enables using hardware handshake 452 (RTS/CTS) and UART's built-in FIFO. Set the number of 453 bytes the interrupt driven input buffer should have. 454 455 Leave undefined to disable this feature, including 456 disable the buffer and hardware handshake. 457 458- Console UART Number: 459 CONFIG_UART1_CONSOLE 460 461 IBM PPC4xx only. 462 If defined internal UART1 (and not UART0) is used 463 as default U-Boot console. 464 465- Boot Delay: CONFIG_BOOTDELAY - in seconds 466 Delay before automatically booting the default image; 467 set to -1 to disable autoboot. 468 469 See doc/README.autoboot for these options that 470 work with CONFIG_BOOTDELAY. None are required. 471 CONFIG_BOOT_RETRY_TIME 472 CONFIG_BOOT_RETRY_MIN 473 CONFIG_AUTOBOOT_KEYED 474 CONFIG_AUTOBOOT_PROMPT 475 CONFIG_AUTOBOOT_DELAY_STR 476 CONFIG_AUTOBOOT_STOP_STR 477 CONFIG_AUTOBOOT_DELAY_STR2 478 CONFIG_AUTOBOOT_STOP_STR2 479 CONFIG_ZERO_BOOTDELAY_CHECK 480 CONFIG_RESET_TO_RETRY 481 482- Autoboot Command: 483 CONFIG_BOOTCOMMAND 484 Only needed when CONFIG_BOOTDELAY is enabled; 485 define a command string that is automatically executed 486 when no character is read on the console interface 487 within "Boot Delay" after reset. 488 489 CONFIG_BOOTARGS 490 This can be used to pass arguments to the bootm 491 command. The value of CONFIG_BOOTARGS goes into the 492 environment value "bootargs". 493 494 CONFIG_RAMBOOT and CONFIG_NFSBOOT 495 The value of these goes into the environment as 496 "ramboot" and "nfsboot" respectively, and can be used 497 as a convenience, when switching between booting from 498 ram and nfs. 499 500- Pre-Boot Commands: 501 CONFIG_PREBOOT 502 503 When this option is #defined, the existence of the 504 environment variable "preboot" will be checked 505 immediately before starting the CONFIG_BOOTDELAY 506 countdown and/or running the auto-boot command resp. 507 entering interactive mode. 508 509 This feature is especially useful when "preboot" is 510 automatically generated or modified. For an example 511 see the LWMON board specific code: here "preboot" is 512 modified when the user holds down a certain 513 combination of keys on the (special) keyboard when 514 booting the systems 515 516- Serial Download Echo Mode: 517 CONFIG_LOADS_ECHO 518 If defined to 1, all characters received during a 519 serial download (using the "loads" command) are 520 echoed back. This might be needed by some terminal 521 emulations (like "cu"), but may as well just take 522 time on others. This setting #define's the initial 523 value of the "loads_echo" environment variable. 524 525- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 526 CONFIG_KGDB_BAUDRATE 527 Select one of the baudrates listed in 528 CFG_BAUDRATE_TABLE, see below. 529 530- Monitor Functions: 531 CONFIG_COMMANDS 532 Most monitor functions can be selected (or 533 de-selected) by adjusting the definition of 534 CONFIG_COMMANDS; to select individual functions, 535 #define CONFIG_COMMANDS by "OR"ing any of the 536 following values: 537 538 #define enables commands: 539 ------------------------- 540 CFG_CMD_ASKENV * ask for env variable 541 CFG_CMD_AUTOSCRIPT Autoscript Support 542 CFG_CMD_BDI bdinfo 543 CFG_CMD_BEDBUG Include BedBug Debugger 544 CFG_CMD_BMP * BMP support 545 CFG_CMD_BOOTD bootd 546 CFG_CMD_CACHE icache, dcache 547 CFG_CMD_CONSOLE coninfo 548 CFG_CMD_DATE * support for RTC, date/time... 549 CFG_CMD_DHCP DHCP support 550 CFG_CMD_DIAG * Diagnostics 551 CFG_CMD_DOC * Disk-On-Chip Support 552 CFG_CMD_DTT Digital Therm and Thermostat 553 CFG_CMD_ECHO * echo arguments 554 CFG_CMD_EEPROM * EEPROM read/write support 555 CFG_CMD_ELF bootelf, bootvx 556 CFG_CMD_ENV saveenv 557 CFG_CMD_FDC * Floppy Disk Support 558 CFG_CMD_FAT FAT partition support 559 CFG_CMD_FDOS * Dos diskette Support 560 CFG_CMD_FLASH flinfo, erase, protect 561 CFG_CMD_FPGA FPGA device initialization support 562 CFG_CMD_HWFLOW * RTS/CTS hw flow control 563 CFG_CMD_I2C * I2C serial bus support 564 CFG_CMD_IDE * IDE harddisk support 565 CFG_CMD_IMI iminfo 566 CFG_CMD_IMLS List all found images 567 CFG_CMD_IMMAP * IMMR dump support 568 CFG_CMD_IRQ * irqinfo 569 CFG_CMD_ITEST * Integer/string test of 2 values 570 CFG_CMD_JFFS2 * JFFS2 Support 571 CFG_CMD_KGDB * kgdb 572 CFG_CMD_LOADB loadb 573 CFG_CMD_LOADS loads 574 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 575 loop, loopw, mtest 576 CFG_CMD_MISC Misc functions like sleep etc 577 CFG_CMD_MMC MMC memory mapped support 578 CFG_CMD_MII MII utility commands 579 CFG_CMD_NAND * NAND support 580 CFG_CMD_NET bootp, tftpboot, rarpboot 581 CFG_CMD_PCI * pciinfo 582 CFG_CMD_PCMCIA * PCMCIA support 583 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host 584 CFG_CMD_PORTIO * Port I/O 585 CFG_CMD_REGINFO * Register dump 586 CFG_CMD_RUN run command in env variable 587 CFG_CMD_SAVES save S record dump 588 CFG_CMD_SCSI * SCSI Support 589 CFG_CMD_SDRAM * print SDRAM configuration information 590 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 591 CFG_CMD_SPI * SPI serial bus support 592 CFG_CMD_USB * USB support 593 CFG_CMD_VFD * VFD support (TRAB) 594 CFG_CMD_BSP * Board SPecific functions 595 CFG_CMD_CDP * Cisco Discover Protocol support 596 ----------------------------------------------- 597 CFG_CMD_ALL all 598 599 CFG_CMD_DFL Default configuration; at the moment 600 this is includes all commands, except 601 the ones marked with "*" in the list 602 above. 603 604 If you don't define CONFIG_COMMANDS it defaults to 605 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 606 override the default settings in the respective 607 include file. 608 609 EXAMPLE: If you want all functions except of network 610 support you can write: 611 612 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 613 614 615 Note: Don't enable the "icache" and "dcache" commands 616 (configuration option CFG_CMD_CACHE) unless you know 617 what you (and your U-Boot users) are doing. Data 618 cache cannot be enabled on systems like the 8xx or 619 8260 (where accesses to the IMMR region must be 620 uncached), and it cannot be disabled on all other 621 systems where we (mis-) use the data cache to hold an 622 initial stack and some data. 623 624 625 XXX - this list needs to get updated! 626 627- Watchdog: 628 CONFIG_WATCHDOG 629 If this variable is defined, it enables watchdog 630 support. There must be support in the platform specific 631 code for a watchdog. For the 8xx and 8260 CPUs, the 632 SIU Watchdog feature is enabled in the SYPCR 633 register. 634 635- U-Boot Version: 636 CONFIG_VERSION_VARIABLE 637 If this variable is defined, an environment variable 638 named "ver" is created by U-Boot showing the U-Boot 639 version as printed by the "version" command. 640 This variable is readonly. 641 642- Real-Time Clock: 643 644 When CFG_CMD_DATE is selected, the type of the RTC 645 has to be selected, too. Define exactly one of the 646 following options: 647 648 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 649 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 650 CONFIG_RTC_MC146818 - use MC146818 RTC 651 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 652 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 653 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 654 CONFIG_RTC_DS164x - use Dallas DS164x RTC 655 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 656 657 Note that if the RTC uses I2C, then the I2C interface 658 must also be configured. See I2C Support, below. 659 660- Timestamp Support: 661 662 When CONFIG_TIMESTAMP is selected, the timestamp 663 (date and time) of an image is printed by image 664 commands like bootm or iminfo. This option is 665 automatically enabled when you select CFG_CMD_DATE . 666 667- Partition Support: 668 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 669 and/or CONFIG_ISO_PARTITION 670 671 If IDE or SCSI support is enabled (CFG_CMD_IDE or 672 CFG_CMD_SCSI) you must configure support for at least 673 one partition type as well. 674 675- IDE Reset method: 676 CONFIG_IDE_RESET_ROUTINE - this is defined in several 677 board configurations files but used nowhere! 678 679 CONFIG_IDE_RESET - is this is defined, IDE Reset will 680 be performed by calling the function 681 ide_set_reset(int reset) 682 which has to be defined in a board specific file 683 684- ATAPI Support: 685 CONFIG_ATAPI 686 687 Set this to enable ATAPI support. 688 689- LBA48 Support 690 CONFIG_LBA48 691 692 Set this to enable support for disks larger than 137GB 693 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 694 Whithout these , LBA48 support uses 32bit variables and will 'only' 695 support disks up to 2.1TB. 696 697 CFG_64BIT_LBA: 698 When enabled, makes the IDE subsystem use 64bit sector addresses. 699 Default is 32bit. 700 701- SCSI Support: 702 At the moment only there is only support for the 703 SYM53C8XX SCSI controller; define 704 CONFIG_SCSI_SYM53C8XX to enable it. 705 706 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 707 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 708 CFG_SCSI_MAX_LUN] can be adjusted to define the 709 maximum numbers of LUNs, SCSI ID's and target 710 devices. 711 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 712 713- NETWORK Support (PCI): 714 CONFIG_E1000 715 Support for Intel 8254x gigabit chips. 716 717 CONFIG_EEPRO100 718 Support for Intel 82557/82559/82559ER chips. 719 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 720 write routine for first time initialisation. 721 722 CONFIG_TULIP 723 Support for Digital 2114x chips. 724 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 725 modem chip initialisation (KS8761/QS6611). 726 727 CONFIG_NATSEMI 728 Support for National dp83815 chips. 729 730 CONFIG_NS8382X 731 Support for National dp8382[01] gigabit chips. 732 733- NETWORK Support (other): 734 735 CONFIG_DRIVER_LAN91C96 736 Support for SMSC's LAN91C96 chips. 737 738 CONFIG_LAN91C96_BASE 739 Define this to hold the physical address 740 of the LAN91C96's I/O space 741 742 CONFIG_LAN91C96_USE_32_BIT 743 Define this to enable 32 bit addressing 744 745 CONFIG_DRIVER_SMC91111 746 Support for SMSC's LAN91C111 chip 747 748 CONFIG_SMC91111_BASE 749 Define this to hold the physical address 750 of the device (I/O space) 751 752 CONFIG_SMC_USE_32_BIT 753 Define this if data bus is 32 bits 754 755 CONFIG_SMC_USE_IOFUNCS 756 Define this to use i/o functions instead of macros 757 (some hardware wont work with macros) 758 759- USB Support: 760 At the moment only the UHCI host controller is 761 supported (PIP405, MIP405, MPC5200); define 762 CONFIG_USB_UHCI to enable it. 763 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 764 end define CONFIG_USB_STORAGE to enable the USB 765 storage devices. 766 Note: 767 Supported are USB Keyboards and USB Floppy drives 768 (TEAC FD-05PUB). 769 MPC5200 USB requires additional defines: 770 CONFIG_USB_CLOCK 771 for 528 MHz Clock: 0x0001bbbb 772 CONFIG_USB_CONFIG 773 for differential drivers: 0x00001000 774 for single ended drivers: 0x00005000 775 776 777- MMC Support: 778 The MMC controller on the Intel PXA is supported. To 779 enable this define CONFIG_MMC. The MMC can be 780 accessed from the boot prompt by mapping the device 781 to physical memory similar to flash. Command line is 782 enabled with CFG_CMD_MMC. The MMC driver also works with 783 the FAT fs. This is enabled with CFG_CMD_FAT. 784 785- Keyboard Support: 786 CONFIG_ISA_KEYBOARD 787 788 Define this to enable standard (PC-Style) keyboard 789 support 790 791 CONFIG_I8042_KBD 792 Standard PC keyboard driver with US (is default) and 793 GERMAN key layout (switch via environment 'keymap=de') support. 794 Export function i8042_kbd_init, i8042_tstc and i8042_getc 795 for cfb_console. Supports cursor blinking. 796 797- Video support: 798 CONFIG_VIDEO 799 800 Define this to enable video support (for output to 801 video). 802 803 CONFIG_VIDEO_CT69000 804 805 Enable Chips & Technologies 69000 Video chip 806 807 CONFIG_VIDEO_SMI_LYNXEM 808 Enable Silicon Motion SMI 712/710/810 Video chip. The 809 video output is selected via environment 'videoout' 810 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 811 assumed. 812 813 For the CT69000 and SMI_LYNXEM drivers, videomode is 814 selected via environment 'videomode'. Two diferent ways 815 are possible: 816 - "videomode=num" 'num' is a standard LiLo mode numbers. 817 Following standard modes are supported (* is default): 818 819 Colors 640x480 800x600 1024x768 1152x864 1280x1024 820 -------------+--------------------------------------------- 821 8 bits | 0x301* 0x303 0x305 0x161 0x307 822 15 bits | 0x310 0x313 0x316 0x162 0x319 823 16 bits | 0x311 0x314 0x317 0x163 0x31A 824 24 bits | 0x312 0x315 0x318 ? 0x31B 825 -------------+--------------------------------------------- 826 (i.e. setenv videomode 317; saveenv; reset;) 827 828 - "videomode=bootargs" all the video parameters are parsed 829 from the bootargs. (See drivers/videomodes.c) 830 831 832 CONFIG_VIDEO_SED13806 833 Enable Epson SED13806 driver. This driver supports 8bpp 834 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 835 or CONFIG_VIDEO_SED13806_16BPP 836 837- Keyboard Support: 838 CONFIG_KEYBOARD 839 840 Define this to enable a custom keyboard support. 841 This simply calls drv_keyboard_init() which must be 842 defined in your board-specific files. 843 The only board using this so far is RBC823. 844 845- LCD Support: CONFIG_LCD 846 847 Define this to enable LCD support (for output to LCD 848 display); also select one of the supported displays 849 by defining one of these: 850 851 CONFIG_NEC_NL6448AC33: 852 853 NEC NL6448AC33-18. Active, color, single scan. 854 855 CONFIG_NEC_NL6448BC20 856 857 NEC NL6448BC20-08. 6.5", 640x480. 858 Active, color, single scan. 859 860 CONFIG_NEC_NL6448BC33_54 861 862 NEC NL6448BC33-54. 10.4", 640x480. 863 Active, color, single scan. 864 865 CONFIG_SHARP_16x9 866 867 Sharp 320x240. Active, color, single scan. 868 It isn't 16x9, and I am not sure what it is. 869 870 CONFIG_SHARP_LQ64D341 871 872 Sharp LQ64D341 display, 640x480. 873 Active, color, single scan. 874 875 CONFIG_HLD1045 876 877 HLD1045 display, 640x480. 878 Active, color, single scan. 879 880 CONFIG_OPTREX_BW 881 882 Optrex CBL50840-2 NF-FW 99 22 M5 883 or 884 Hitachi LMG6912RPFC-00T 885 or 886 Hitachi SP14Q002 887 888 320x240. Black & white. 889 890 Normally display is black on white background; define 891 CFG_WHITE_ON_BLACK to get it inverted. 892 893- Splash Screen Support: CONFIG_SPLASH_SCREEN 894 895 If this option is set, the environment is checked for 896 a variable "splashimage". If found, the usual display 897 of logo, copyright and system information on the LCD 898 is suppressed and the BMP image at the address 899 specified in "splashimage" is loaded instead. The 900 console is redirected to the "nulldev", too. This 901 allows for a "silent" boot where a splash screen is 902 loaded very quickly after power-on. 903 904- Compression support: 905 CONFIG_BZIP2 906 907 If this option is set, support for bzip2 compressed 908 images is included. If not, only uncompressed and gzip 909 compressed images are supported. 910 911 NOTE: the bzip2 algorithm requires a lot of RAM, so 912 the malloc area (as defined by CFG_MALLOC_LEN) should 913 be at least 4MB. 914 915- MII/PHY support: 916 CONFIG_PHY_ADDR 917 918 The address of PHY on MII bus. 919 920 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 921 922 The clock frequency of the MII bus 923 924 CONFIG_PHY_GIGE 925 926 If this option is set, support for speed/duplex 927 detection of Gigabit PHY is included. 928 929 CONFIG_PHY_RESET_DELAY 930 931 Some PHY like Intel LXT971A need extra delay after 932 reset before any MII register access is possible. 933 For such PHY, set this option to the usec delay 934 required. (minimum 300usec for LXT971A) 935 936 CONFIG_PHY_CMD_DELAY (ppc4xx) 937 938 Some PHY like Intel LXT971A need extra delay after 939 command issued before MII status register can be read 940 941- Ethernet address: 942 CONFIG_ETHADDR 943 CONFIG_ETH2ADDR 944 CONFIG_ETH3ADDR 945 946 Define a default value for ethernet address to use 947 for the respective ethernet interface, in case this 948 is not determined automatically. 949 950- IP address: 951 CONFIG_IPADDR 952 953 Define a default value for the IP address to use for 954 the default ethernet interface, in case this is not 955 determined through e.g. bootp. 956 957- Server IP address: 958 CONFIG_SERVERIP 959 960 Defines a default value for theIP address of a TFTP 961 server to contact when using the "tftboot" command. 962 963- BOOTP Recovery Mode: 964 CONFIG_BOOTP_RANDOM_DELAY 965 966 If you have many targets in a network that try to 967 boot using BOOTP, you may want to avoid that all 968 systems send out BOOTP requests at precisely the same 969 moment (which would happen for instance at recovery 970 from a power failure, when all systems will try to 971 boot, thus flooding the BOOTP server. Defining 972 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 973 inserted before sending out BOOTP requests. The 974 following delays are insterted then: 975 976 1st BOOTP request: delay 0 ... 1 sec 977 2nd BOOTP request: delay 0 ... 2 sec 978 3rd BOOTP request: delay 0 ... 4 sec 979 4th and following 980 BOOTP requests: delay 0 ... 8 sec 981 982- DHCP Advanced Options: 983 CONFIG_BOOTP_MASK 984 985 You can fine tune the DHCP functionality by adding 986 these flags to the CONFIG_BOOTP_MASK define: 987 988 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 989 serverip from a DHCP server, it is possible that more 990 than one DNS serverip is offered to the client. 991 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 992 serverip will be stored in the additional environment 993 variable "dnsip2". The first DNS serverip is always 994 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 995 is added to the CONFIG_BOOTP_MASK. 996 997 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 998 to do a dynamic update of a DNS server. To do this, they 999 need the hostname of the DHCP requester. 1000 If CONFIG_BOOP_SEND_HOSTNAME is added to the 1001 CONFIG_BOOTP_MASK, the content of the "hostname" 1002 environment variable is passed as option 12 to 1003 the DHCP server. 1004 1005 - CDP Options: 1006 CONFIG_CDP_DEVICE_ID 1007 1008 The device id used in CDP trigger frames. 1009 1010 CONFIG_CDP_DEVICE_ID_PREFIX 1011 1012 A two character string which is prefixed to the MAC address 1013 of the device. 1014 1015 CONFIG_CDP_PORT_ID 1016 1017 A printf format string which contains the ascii name of 1018 the port. Normally is set to "eth%d" which sets 1019 eth0 for the first ethernet, eth1 for the second etc. 1020 1021 CONFIG_CDP_CAPABILITIES 1022 1023 A 32bit integer which indicates the device capabilities; 1024 0x00000010 for a normal host which does not forwards. 1025 1026 CONFIG_CDP_VERSION 1027 1028 An ascii string containing the version of the software. 1029 1030 CONFIG_CDP_PLATFORM 1031 1032 An ascii string containing the name of the platform. 1033 1034 CONFIG_CDP_TRIGGER 1035 1036 A 32bit integer sent on the trigger. 1037 1038 CONFIG_CDP_POWER_CONSUMPTION 1039 1040 A 16bit integer containing the power consumption of the 1041 device in .1 of milliwatts. 1042 1043 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1044 1045 A byte containing the id of the VLAN. 1046 1047- Status LED: CONFIG_STATUS_LED 1048 1049 Several configurations allow to display the current 1050 status using a LED. For instance, the LED will blink 1051 fast while running U-Boot code, stop blinking as 1052 soon as a reply to a BOOTP request was received, and 1053 start blinking slow once the Linux kernel is running 1054 (supported by a status LED driver in the Linux 1055 kernel). Defining CONFIG_STATUS_LED enables this 1056 feature in U-Boot. 1057 1058- CAN Support: CONFIG_CAN_DRIVER 1059 1060 Defining CONFIG_CAN_DRIVER enables CAN driver support 1061 on those systems that support this (optional) 1062 feature, like the TQM8xxL modules. 1063 1064- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1065 1066 These enable I2C serial bus commands. Defining either of 1067 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1068 include the appropriate I2C driver for the selected cpu. 1069 1070 This will allow you to use i2c commands at the u-boot 1071 command line (as long as you set CFG_CMD_I2C in 1072 CONFIG_COMMANDS) and communicate with i2c based realtime 1073 clock chips. See common/cmd_i2c.c for a description of the 1074 command line interface. 1075 1076 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 1077 1078 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1079 bit-banging) driver instead of CPM or similar hardware 1080 support for I2C. 1081 1082 There are several other quantities that must also be 1083 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1084 1085 In both cases you will need to define CFG_I2C_SPEED 1086 to be the frequency (in Hz) at which you wish your i2c bus 1087 to run and CFG_I2C_SLAVE to be the address of this node (ie 1088 the cpu's i2c node address). 1089 1090 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1091 sets the cpu up as a master node and so its address should 1092 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1093 p.16-473). So, set CFG_I2C_SLAVE to 0. 1094 1095 That's all that's required for CONFIG_HARD_I2C. 1096 1097 If you use the software i2c interface (CONFIG_SOFT_I2C) 1098 then the following macros need to be defined (examples are 1099 from include/configs/lwmon.h): 1100 1101 I2C_INIT 1102 1103 (Optional). Any commands necessary to enable the I2C 1104 controller or configure ports. 1105 1106 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1107 1108 I2C_PORT 1109 1110 (Only for MPC8260 CPU). The I/O port to use (the code 1111 assumes both bits are on the same port). Valid values 1112 are 0..3 for ports A..D. 1113 1114 I2C_ACTIVE 1115 1116 The code necessary to make the I2C data line active 1117 (driven). If the data line is open collector, this 1118 define can be null. 1119 1120 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1121 1122 I2C_TRISTATE 1123 1124 The code necessary to make the I2C data line tri-stated 1125 (inactive). If the data line is open collector, this 1126 define can be null. 1127 1128 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1129 1130 I2C_READ 1131 1132 Code that returns TRUE if the I2C data line is high, 1133 FALSE if it is low. 1134 1135 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1136 1137 I2C_SDA(bit) 1138 1139 If <bit> is TRUE, sets the I2C data line high. If it 1140 is FALSE, it clears it (low). 1141 1142 eg: #define I2C_SDA(bit) \ 1143 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1144 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1145 1146 I2C_SCL(bit) 1147 1148 If <bit> is TRUE, sets the I2C clock line high. If it 1149 is FALSE, it clears it (low). 1150 1151 eg: #define I2C_SCL(bit) \ 1152 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1153 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1154 1155 I2C_DELAY 1156 1157 This delay is invoked four times per clock cycle so this 1158 controls the rate of data transfer. The data rate thus 1159 is 1 / (I2C_DELAY * 4). Often defined to be something 1160 like: 1161 1162 #define I2C_DELAY udelay(2) 1163 1164 CFG_I2C_INIT_BOARD 1165 1166 When a board is reset during an i2c bus transfer 1167 chips might think that the current transfer is still 1168 in progress. On some boards it is possible to access 1169 the i2c SCLK line directly, either by using the 1170 processor pin as a GPIO or by having a second pin 1171 connected to the bus. If this option is defined a 1172 custom i2c_init_board() routine in boards/xxx/board.c 1173 is run early in the boot sequence. 1174 1175 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1176 1177 This option enables configuration of bi_iic_fast[] flags 1178 in u-boot bd_info structure based on u-boot environment 1179 variable "i2cfast". (see also i2cfast) 1180 1181- SPI Support: CONFIG_SPI 1182 1183 Enables SPI driver (so far only tested with 1184 SPI EEPROM, also an instance works with Crystal A/D and 1185 D/As on the SACSng board) 1186 1187 CONFIG_SPI_X 1188 1189 Enables extended (16-bit) SPI EEPROM addressing. 1190 (symmetrical to CONFIG_I2C_X) 1191 1192 CONFIG_SOFT_SPI 1193 1194 Enables a software (bit-bang) SPI driver rather than 1195 using hardware support. This is a general purpose 1196 driver that only requires three general I/O port pins 1197 (two outputs, one input) to function. If this is 1198 defined, the board configuration must define several 1199 SPI configuration items (port pins to use, etc). For 1200 an example, see include/configs/sacsng.h. 1201 1202- FPGA Support: CONFIG_FPGA_COUNT 1203 1204 Specify the number of FPGA devices to support. 1205 1206 CONFIG_FPGA 1207 1208 Used to specify the types of FPGA devices. For example, 1209 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1210 1211 CFG_FPGA_PROG_FEEDBACK 1212 1213 Enable printing of hash marks during FPGA configuration. 1214 1215 CFG_FPGA_CHECK_BUSY 1216 1217 Enable checks on FPGA configuration interface busy 1218 status by the configuration function. This option 1219 will require a board or device specific function to 1220 be written. 1221 1222 CONFIG_FPGA_DELAY 1223 1224 If defined, a function that provides delays in the FPGA 1225 configuration driver. 1226 1227 CFG_FPGA_CHECK_CTRLC 1228 Allow Control-C to interrupt FPGA configuration 1229 1230 CFG_FPGA_CHECK_ERROR 1231 1232 Check for configuration errors during FPGA bitfile 1233 loading. For example, abort during Virtex II 1234 configuration if the INIT_B line goes low (which 1235 indicated a CRC error). 1236 1237 CFG_FPGA_WAIT_INIT 1238 1239 Maximum time to wait for the INIT_B line to deassert 1240 after PROB_B has been deasserted during a Virtex II 1241 FPGA configuration sequence. The default time is 500 1242 mS. 1243 1244 CFG_FPGA_WAIT_BUSY 1245 1246 Maximum time to wait for BUSY to deassert during 1247 Virtex II FPGA configuration. The default is 5 mS. 1248 1249 CFG_FPGA_WAIT_CONFIG 1250 1251 Time to wait after FPGA configuration. The default is 1252 200 mS. 1253 1254- Configuration Management: 1255 CONFIG_IDENT_STRING 1256 1257 If defined, this string will be added to the U-Boot 1258 version information (U_BOOT_VERSION) 1259 1260- Vendor Parameter Protection: 1261 1262 U-Boot considers the values of the environment 1263 variables "serial#" (Board Serial Number) and 1264 "ethaddr" (Ethernet Address) to be parameters that 1265 are set once by the board vendor / manufacturer, and 1266 protects these variables from casual modification by 1267 the user. Once set, these variables are read-only, 1268 and write or delete attempts are rejected. You can 1269 change this behviour: 1270 1271 If CONFIG_ENV_OVERWRITE is #defined in your config 1272 file, the write protection for vendor parameters is 1273 completely disabled. Anybody can change or delete 1274 these parameters. 1275 1276 Alternatively, if you #define _both_ CONFIG_ETHADDR 1277 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1278 ethernet address is installed in the environment, 1279 which can be changed exactly ONCE by the user. [The 1280 serial# is unaffected by this, i. e. it remains 1281 read-only.] 1282 1283- Protected RAM: 1284 CONFIG_PRAM 1285 1286 Define this variable to enable the reservation of 1287 "protected RAM", i. e. RAM which is not overwritten 1288 by U-Boot. Define CONFIG_PRAM to hold the number of 1289 kB you want to reserve for pRAM. You can overwrite 1290 this default value by defining an environment 1291 variable "pram" to the number of kB you want to 1292 reserve. Note that the board info structure will 1293 still show the full amount of RAM. If pRAM is 1294 reserved, a new environment variable "mem" will 1295 automatically be defined to hold the amount of 1296 remaining RAM in a form that can be passed as boot 1297 argument to Linux, for instance like that: 1298 1299 setenv bootargs ... mem=\$(mem) 1300 saveenv 1301 1302 This way you can tell Linux not to use this memory, 1303 either, which results in a memory region that will 1304 not be affected by reboots. 1305 1306 *WARNING* If your board configuration uses automatic 1307 detection of the RAM size, you must make sure that 1308 this memory test is non-destructive. So far, the 1309 following board configurations are known to be 1310 "pRAM-clean": 1311 1312 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1313 HERMES, IP860, RPXlite, LWMON, LANTEC, 1314 PCU_E, FLAGADM, TQM8260 1315 1316- Error Recovery: 1317 CONFIG_PANIC_HANG 1318 1319 Define this variable to stop the system in case of a 1320 fatal error, so that you have to reset it manually. 1321 This is probably NOT a good idea for an embedded 1322 system where you want to system to reboot 1323 automatically as fast as possible, but it may be 1324 useful during development since you can try to debug 1325 the conditions that lead to the situation. 1326 1327 CONFIG_NET_RETRY_COUNT 1328 1329 This variable defines the number of retries for 1330 network operations like ARP, RARP, TFTP, or BOOTP 1331 before giving up the operation. If not defined, a 1332 default value of 5 is used. 1333 1334- Command Interpreter: 1335 CFG_AUTO_COMPLETE 1336 1337 Enable auto completion of commands using TAB. 1338 1339 CFG_HUSH_PARSER 1340 1341 Define this variable to enable the "hush" shell (from 1342 Busybox) as command line interpreter, thus enabling 1343 powerful command line syntax like 1344 if...then...else...fi conditionals or `&&' and '||' 1345 constructs ("shell scripts"). 1346 1347 If undefined, you get the old, much simpler behaviour 1348 with a somewhat smaller memory footprint. 1349 1350 1351 CFG_PROMPT_HUSH_PS2 1352 1353 This defines the secondary prompt string, which is 1354 printed when the command interpreter needs more input 1355 to complete a command. Usually "> ". 1356 1357 Note: 1358 1359 In the current implementation, the local variables 1360 space and global environment variables space are 1361 separated. Local variables are those you define by 1362 simply typing `name=value'. To access a local 1363 variable later on, you have write `$name' or 1364 `${name}'; to execute the contents of a variable 1365 directly type `$name' at the command prompt. 1366 1367 Global environment variables are those you use 1368 setenv/printenv to work with. To run a command stored 1369 in such a variable, you need to use the run command, 1370 and you must not use the '$' sign to access them. 1371 1372 To store commands and special characters in a 1373 variable, please use double quotation marks 1374 surrounding the whole text of the variable, instead 1375 of the backslashes before semicolons and special 1376 symbols. 1377 1378- Default Environment: 1379 CONFIG_EXTRA_ENV_SETTINGS 1380 1381 Define this to contain any number of null terminated 1382 strings (variable = value pairs) that will be part of 1383 the default environment compiled into the boot image. 1384 1385 For example, place something like this in your 1386 board's config file: 1387 1388 #define CONFIG_EXTRA_ENV_SETTINGS \ 1389 "myvar1=value1\0" \ 1390 "myvar2=value2\0" 1391 1392 Warning: This method is based on knowledge about the 1393 internal format how the environment is stored by the 1394 U-Boot code. This is NOT an official, exported 1395 interface! Although it is unlikely that this format 1396 will change soon, there is no guarantee either. 1397 You better know what you are doing here. 1398 1399 Note: overly (ab)use of the default environment is 1400 discouraged. Make sure to check other ways to preset 1401 the environment like the autoscript function or the 1402 boot command first. 1403 1404- DataFlash Support: 1405 CONFIG_HAS_DATAFLASH 1406 1407 Defining this option enables DataFlash features and 1408 allows to read/write in Dataflash via the standard 1409 commands cp, md... 1410 1411- SystemACE Support: 1412 CONFIG_SYSTEMACE 1413 1414 Adding this option adds support for Xilinx SystemACE 1415 chips attached via some sort of local bus. The address 1416 of the chip must alsh be defined in the 1417 CFG_SYSTEMACE_BASE macro. For example: 1418 1419 #define CONFIG_SYSTEMACE 1420 #define CFG_SYSTEMACE_BASE 0xf0000000 1421 1422 When SystemACE support is added, the "ace" device type 1423 becomes available to the fat commands, i.e. fatls. 1424 1425- Show boot progress: 1426 CONFIG_SHOW_BOOT_PROGRESS 1427 1428 Defining this option allows to add some board- 1429 specific code (calling a user-provided function 1430 "show_boot_progress(int)") that enables you to show 1431 the system's boot progress on some display (for 1432 example, some LED's) on your board. At the moment, 1433 the following checkpoints are implemented: 1434 1435 Arg Where When 1436 1 common/cmd_bootm.c before attempting to boot an image 1437 -1 common/cmd_bootm.c Image header has bad magic number 1438 2 common/cmd_bootm.c Image header has correct magic number 1439 -2 common/cmd_bootm.c Image header has bad checksum 1440 3 common/cmd_bootm.c Image header has correct checksum 1441 -3 common/cmd_bootm.c Image data has bad checksum 1442 4 common/cmd_bootm.c Image data has correct checksum 1443 -4 common/cmd_bootm.c Image is for unsupported architecture 1444 5 common/cmd_bootm.c Architecture check OK 1445 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1446 6 common/cmd_bootm.c Image Type check OK 1447 -6 common/cmd_bootm.c gunzip uncompression error 1448 -7 common/cmd_bootm.c Unimplemented compression type 1449 7 common/cmd_bootm.c Uncompression OK 1450 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1451 8 common/cmd_bootm.c Image Type check OK 1452 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1453 9 common/cmd_bootm.c Start initial ramdisk verification 1454 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1455 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1456 10 common/cmd_bootm.c Ramdisk header is OK 1457 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1458 11 common/cmd_bootm.c Ramdisk data has correct checksum 1459 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1460 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1461 13 common/cmd_bootm.c Start multifile image verification 1462 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1463 15 common/cmd_bootm.c All preparation done, transferring control to OS 1464 1465 -30 lib_ppc/board.c Fatal error, hang the system 1466 -31 post/post.c POST test failed, detected by post_output_backlog() 1467 -32 post/post.c POST test failed, detected by post_run_single() 1468 1469 -1 common/cmd_doc.c Bad usage of "doc" command 1470 -1 common/cmd_doc.c No boot device 1471 -1 common/cmd_doc.c Unknown Chip ID on boot device 1472 -1 common/cmd_doc.c Read Error on boot device 1473 -1 common/cmd_doc.c Image header has bad magic number 1474 1475 -1 common/cmd_ide.c Bad usage of "ide" command 1476 -1 common/cmd_ide.c No boot device 1477 -1 common/cmd_ide.c Unknown boot device 1478 -1 common/cmd_ide.c Unknown partition table 1479 -1 common/cmd_ide.c Invalid partition type 1480 -1 common/cmd_ide.c Read Error on boot device 1481 -1 common/cmd_ide.c Image header has bad magic number 1482 1483 -1 common/cmd_nand.c Bad usage of "nand" command 1484 -1 common/cmd_nand.c No boot device 1485 -1 common/cmd_nand.c Unknown Chip ID on boot device 1486 -1 common/cmd_nand.c Read Error on boot device 1487 -1 common/cmd_nand.c Image header has bad magic number 1488 1489 -1 common/env_common.c Environment has a bad CRC, using default 1490 1491 1492Modem Support: 1493-------------- 1494 1495[so far only for SMDK2400 and TRAB boards] 1496 1497- Modem support endable: 1498 CONFIG_MODEM_SUPPORT 1499 1500- RTS/CTS Flow control enable: 1501 CONFIG_HWFLOW 1502 1503- Modem debug support: 1504 CONFIG_MODEM_SUPPORT_DEBUG 1505 1506 Enables debugging stuff (char screen[1024], dbg()) 1507 for modem support. Useful only with BDI2000. 1508 1509- Interrupt support (PPC): 1510 1511 There are common interrupt_init() and timer_interrupt() 1512 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1513 for cpu specific initialization. interrupt_init_cpu() 1514 should set decrementer_count to appropriate value. If 1515 cpu resets decrementer automatically after interrupt 1516 (ppc4xx) it should set decrementer_count to zero. 1517 timer_interrupt() calls timer_interrupt_cpu() for cpu 1518 specific handling. If board has watchdog / status_led 1519 / other_activity_monitor it works automatically from 1520 general timer_interrupt(). 1521 1522- General: 1523 1524 In the target system modem support is enabled when a 1525 specific key (key combination) is pressed during 1526 power-on. Otherwise U-Boot will boot normally 1527 (autoboot). The key_pressed() fuction is called from 1528 board_init(). Currently key_pressed() is a dummy 1529 function, returning 1 and thus enabling modem 1530 initialization. 1531 1532 If there are no modem init strings in the 1533 environment, U-Boot proceed to autoboot; the 1534 previous output (banner, info printfs) will be 1535 supressed, though. 1536 1537 See also: doc/README.Modem 1538 1539 1540Configuration Settings: 1541----------------------- 1542 1543- CFG_LONGHELP: Defined when you want long help messages included; 1544 undefine this when you're short of memory. 1545 1546- CFG_PROMPT: This is what U-Boot prints on the console to 1547 prompt for user input. 1548 1549- CFG_CBSIZE: Buffer size for input from the Console 1550 1551- CFG_PBSIZE: Buffer size for Console output 1552 1553- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1554 1555- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1556 the application (usually a Linux kernel) when it is 1557 booted 1558 1559- CFG_BAUDRATE_TABLE: 1560 List of legal baudrate settings for this board. 1561 1562- CFG_CONSOLE_INFO_QUIET 1563 Suppress display of console information at boot. 1564 1565- CFG_CONSOLE_IS_IN_ENV 1566 If the board specific function 1567 extern int overwrite_console (void); 1568 returns 1, the stdin, stderr and stdout are switched to the 1569 serial port, else the settings in the environment are used. 1570 1571- CFG_CONSOLE_OVERWRITE_ROUTINE 1572 Enable the call to overwrite_console(). 1573 1574- CFG_CONSOLE_ENV_OVERWRITE 1575 Enable overwrite of previous console environment settings. 1576 1577- CFG_MEMTEST_START, CFG_MEMTEST_END: 1578 Begin and End addresses of the area used by the 1579 simple memory test. 1580 1581- CFG_ALT_MEMTEST: 1582 Enable an alternate, more extensive memory test. 1583 1584- CFG_MEMTEST_SCRATCH: 1585 Scratch address used by the alternate memory test 1586 You only need to set this if address zero isn't writeable 1587 1588- CFG_TFTP_LOADADDR: 1589 Default load address for network file downloads 1590 1591- CFG_LOADS_BAUD_CHANGE: 1592 Enable temporary baudrate change while serial download 1593 1594- CFG_SDRAM_BASE: 1595 Physical start address of SDRAM. _Must_ be 0 here. 1596 1597- CFG_MBIO_BASE: 1598 Physical start address of Motherboard I/O (if using a 1599 Cogent motherboard) 1600 1601- CFG_FLASH_BASE: 1602 Physical start address of Flash memory. 1603 1604- CFG_MONITOR_BASE: 1605 Physical start address of boot monitor code (set by 1606 make config files to be same as the text base address 1607 (TEXT_BASE) used when linking) - same as 1608 CFG_FLASH_BASE when booting from flash. 1609 1610- CFG_MONITOR_LEN: 1611 Size of memory reserved for monitor code, used to 1612 determine _at_compile_time_ (!) if the environment is 1613 embedded within the U-Boot image, or in a separate 1614 flash sector. 1615 1616- CFG_MALLOC_LEN: 1617 Size of DRAM reserved for malloc() use. 1618 1619- CFG_BOOTMAPSZ: 1620 Maximum size of memory mapped by the startup code of 1621 the Linux kernel; all data that must be processed by 1622 the Linux kernel (bd_info, boot arguments, eventually 1623 initrd image) must be put below this limit. 1624 1625- CFG_MAX_FLASH_BANKS: 1626 Max number of Flash memory banks 1627 1628- CFG_MAX_FLASH_SECT: 1629 Max number of sectors on a Flash chip 1630 1631- CFG_FLASH_ERASE_TOUT: 1632 Timeout for Flash erase operations (in ms) 1633 1634- CFG_FLASH_WRITE_TOUT: 1635 Timeout for Flash write operations (in ms) 1636 1637- CFG_FLASH_LOCK_TOUT 1638 Timeout for Flash set sector lock bit operation (in ms) 1639 1640- CFG_FLASH_UNLOCK_TOUT 1641 Timeout for Flash clear lock bits operation (in ms) 1642 1643- CFG_FLASH_PROTECTION 1644 If defined, hardware flash sectors protection is used 1645 instead of U-Boot software protection. 1646 1647- CFG_DIRECT_FLASH_TFTP: 1648 1649 Enable TFTP transfers directly to flash memory; 1650 without this option such a download has to be 1651 performed in two steps: (1) download to RAM, and (2) 1652 copy from RAM to flash. 1653 1654 The two-step approach is usually more reliable, since 1655 you can check if the download worked before you erase 1656 the flash, but in some situations (when sytem RAM is 1657 too limited to allow for a tempory copy of the 1658 downloaded image) this option may be very useful. 1659 1660- CFG_FLASH_CFI: 1661 Define if the flash driver uses extra elements in the 1662 common flash structure for storing flash geometry. 1663 1664- CFG_FLASH_CFI_DRIVER 1665 This option also enables the building of the cfi_flash driver 1666 in the drivers directory 1667 1668- CFG_RX_ETH_BUFFER: 1669 Defines the number of ethernet receive buffers. On some 1670 ethernet controllers it is recommended to set this value 1671 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1672 buffers can be full shortly after enabling the interface 1673 on high ethernet traffic. 1674 Defaults to 4 if not defined. 1675 1676The following definitions that deal with the placement and management 1677of environment data (variable area); in general, we support the 1678following configurations: 1679 1680- CFG_ENV_IS_IN_FLASH: 1681 1682 Define this if the environment is in flash memory. 1683 1684 a) The environment occupies one whole flash sector, which is 1685 "embedded" in the text segment with the U-Boot code. This 1686 happens usually with "bottom boot sector" or "top boot 1687 sector" type flash chips, which have several smaller 1688 sectors at the start or the end. For instance, such a 1689 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1690 such a case you would place the environment in one of the 1691 4 kB sectors - with U-Boot code before and after it. With 1692 "top boot sector" type flash chips, you would put the 1693 environment in one of the last sectors, leaving a gap 1694 between U-Boot and the environment. 1695 1696 - CFG_ENV_OFFSET: 1697 1698 Offset of environment data (variable area) to the 1699 beginning of flash memory; for instance, with bottom boot 1700 type flash chips the second sector can be used: the offset 1701 for this sector is given here. 1702 1703 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1704 1705 - CFG_ENV_ADDR: 1706 1707 This is just another way to specify the start address of 1708 the flash sector containing the environment (instead of 1709 CFG_ENV_OFFSET). 1710 1711 - CFG_ENV_SECT_SIZE: 1712 1713 Size of the sector containing the environment. 1714 1715 1716 b) Sometimes flash chips have few, equal sized, BIG sectors. 1717 In such a case you don't want to spend a whole sector for 1718 the environment. 1719 1720 - CFG_ENV_SIZE: 1721 1722 If you use this in combination with CFG_ENV_IS_IN_FLASH 1723 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1724 of this flash sector for the environment. This saves 1725 memory for the RAM copy of the environment. 1726 1727 It may also save flash memory if you decide to use this 1728 when your environment is "embedded" within U-Boot code, 1729 since then the remainder of the flash sector could be used 1730 for U-Boot code. It should be pointed out that this is 1731 STRONGLY DISCOURAGED from a robustness point of view: 1732 updating the environment in flash makes it always 1733 necessary to erase the WHOLE sector. If something goes 1734 wrong before the contents has been restored from a copy in 1735 RAM, your target system will be dead. 1736 1737 - CFG_ENV_ADDR_REDUND 1738 CFG_ENV_SIZE_REDUND 1739 1740 These settings describe a second storage area used to hold 1741 a redundand copy of the environment data, so that there is 1742 a valid backup copy in case there is a power failure during 1743 a "saveenv" operation. 1744 1745BE CAREFUL! Any changes to the flash layout, and some changes to the 1746source code will make it necessary to adapt <board>/u-boot.lds* 1747accordingly! 1748 1749 1750- CFG_ENV_IS_IN_NVRAM: 1751 1752 Define this if you have some non-volatile memory device 1753 (NVRAM, battery buffered SRAM) which you want to use for the 1754 environment. 1755 1756 - CFG_ENV_ADDR: 1757 - CFG_ENV_SIZE: 1758 1759 These two #defines are used to determin the memory area you 1760 want to use for environment. It is assumed that this memory 1761 can just be read and written to, without any special 1762 provision. 1763 1764BE CAREFUL! The first access to the environment happens quite early 1765in U-Boot initalization (when we try to get the setting of for the 1766console baudrate). You *MUST* have mappend your NVRAM area then, or 1767U-Boot will hang. 1768 1769Please note that even with NVRAM we still use a copy of the 1770environment in RAM: we could work on NVRAM directly, but we want to 1771keep settings there always unmodified except somebody uses "saveenv" 1772to save the current settings. 1773 1774 1775- CFG_ENV_IS_IN_EEPROM: 1776 1777 Use this if you have an EEPROM or similar serial access 1778 device and a driver for it. 1779 1780 - CFG_ENV_OFFSET: 1781 - CFG_ENV_SIZE: 1782 1783 These two #defines specify the offset and size of the 1784 environment area within the total memory of your EEPROM. 1785 1786 - CFG_I2C_EEPROM_ADDR: 1787 If defined, specified the chip address of the EEPROM device. 1788 The default address is zero. 1789 1790 - CFG_EEPROM_PAGE_WRITE_BITS: 1791 If defined, the number of bits used to address bytes in a 1792 single page in the EEPROM device. A 64 byte page, for example 1793 would require six bits. 1794 1795 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1796 If defined, the number of milliseconds to delay between 1797 page writes. The default is zero milliseconds. 1798 1799 - CFG_I2C_EEPROM_ADDR_LEN: 1800 The length in bytes of the EEPROM memory array address. Note 1801 that this is NOT the chip address length! 1802 1803 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 1804 EEPROM chips that implement "address overflow" are ones 1805 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 1806 address and the extra bits end up in the "chip address" bit 1807 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 1808 byte chips. 1809 1810 Note that we consider the length of the address field to 1811 still be one byte because the extra address bits are hidden 1812 in the chip address. 1813 1814 - CFG_EEPROM_SIZE: 1815 The size in bytes of the EEPROM device. 1816 1817 1818- CFG_ENV_IS_IN_DATAFLASH: 1819 1820 Define this if you have a DataFlash memory device which you 1821 want to use for the environment. 1822 1823 - CFG_ENV_OFFSET: 1824 - CFG_ENV_ADDR: 1825 - CFG_ENV_SIZE: 1826 1827 These three #defines specify the offset and size of the 1828 environment area within the total memory of your DataFlash placed 1829 at the specified address. 1830 1831- CFG_ENV_IS_IN_NAND: 1832 1833 Define this if you have a NAND device which you want to use 1834 for the environment. 1835 1836 - CFG_ENV_OFFSET: 1837 - CFG_ENV_SIZE: 1838 1839 These two #defines specify the offset and size of the environment 1840 area within the first NAND device. 1841 1842- CFG_SPI_INIT_OFFSET 1843 1844 Defines offset to the initial SPI buffer area in DPRAM. The 1845 area is used at an early stage (ROM part) if the environment 1846 is configured to reside in the SPI EEPROM: We need a 520 byte 1847 scratch DPRAM area. It is used between the two initialization 1848 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1849 to be a good choice since it makes it far enough from the 1850 start of the data area as well as from the stack pointer. 1851 1852Please note that the environment is read-only as long as the monitor 1853has been relocated to RAM and a RAM copy of the environment has been 1854created; also, when using EEPROM you will have to use getenv_r() 1855until then to read environment variables. 1856 1857The environment is protected by a CRC32 checksum. Before the monitor 1858is relocated into RAM, as a result of a bad CRC you will be working 1859with the compiled-in default environment - *silently*!!! [This is 1860necessary, because the first environment variable we need is the 1861"baudrate" setting for the console - if we have a bad CRC, we don't 1862have any device yet where we could complain.] 1863 1864Note: once the monitor has been relocated, then it will complain if 1865the default environment is used; a new CRC is computed as soon as you 1866use the "saveenv" command to store a valid environment. 1867 1868- CFG_FAULT_ECHO_LINK_DOWN: 1869 Echo the inverted Ethernet link state to the fault LED. 1870 1871 Note: If this option is active, then CFG_FAULT_MII_ADDR 1872 also needs to be defined. 1873 1874- CFG_FAULT_MII_ADDR: 1875 MII address of the PHY to check for the Ethernet link state. 1876 1877- CFG_64BIT_VSPRINTF: 1878 Makes vsprintf (and all *printf functions) support printing 1879 of 64bit values by using the L quantifier 1880 1881- CFG_64BIT_STRTOUL: 1882 Adds simple_strtoull that returns a 64bit value 1883 1884Low Level (hardware related) configuration options: 1885--------------------------------------------------- 1886 1887- CFG_CACHELINE_SIZE: 1888 Cache Line Size of the CPU. 1889 1890- CFG_DEFAULT_IMMR: 1891 Default address of the IMMR after system reset. 1892 1893 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1894 and RPXsuper) to be able to adjust the position of 1895 the IMMR register after a reset. 1896 1897- Floppy Disk Support: 1898 CFG_FDC_DRIVE_NUMBER 1899 1900 the default drive number (default value 0) 1901 1902 CFG_ISA_IO_STRIDE 1903 1904 defines the spacing between fdc chipset registers 1905 (default value 1) 1906 1907 CFG_ISA_IO_OFFSET 1908 1909 defines the offset of register from address. It 1910 depends on which part of the data bus is connected to 1911 the fdc chipset. (default value 0) 1912 1913 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1914 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1915 default value. 1916 1917 if CFG_FDC_HW_INIT is defined, then the function 1918 fdc_hw_init() is called at the beginning of the FDC 1919 setup. fdc_hw_init() must be provided by the board 1920 source code. It is used to make hardware dependant 1921 initializations. 1922 1923- CFG_IMMR: Physical address of the Internal Memory Mapped 1924 Register; DO NOT CHANGE! (11-4) 1925 [MPC8xx systems only] 1926 1927- CFG_INIT_RAM_ADDR: 1928 1929 Start address of memory area that can be used for 1930 initial data and stack; please note that this must be 1931 writable memory that is working WITHOUT special 1932 initialization, i. e. you CANNOT use normal RAM which 1933 will become available only after programming the 1934 memory controller and running certain initialization 1935 sequences. 1936 1937 U-Boot uses the following memory types: 1938 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1939 - MPC824X: data cache 1940 - PPC4xx: data cache 1941 1942- CFG_GBL_DATA_OFFSET: 1943 1944 Offset of the initial data structure in the memory 1945 area defined by CFG_INIT_RAM_ADDR. Usually 1946 CFG_GBL_DATA_OFFSET is chosen such that the initial 1947 data is located at the end of the available space 1948 (sometimes written as (CFG_INIT_RAM_END - 1949 CFG_INIT_DATA_SIZE), and the initial stack is just 1950 below that area (growing from (CFG_INIT_RAM_ADDR + 1951 CFG_GBL_DATA_OFFSET) downward. 1952 1953 Note: 1954 On the MPC824X (or other systems that use the data 1955 cache for initial memory) the address chosen for 1956 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1957 point to an otherwise UNUSED address space between 1958 the top of RAM and the start of the PCI space. 1959 1960- CFG_SIUMCR: SIU Module Configuration (11-6) 1961 1962- CFG_SYPCR: System Protection Control (11-9) 1963 1964- CFG_TBSCR: Time Base Status and Control (11-26) 1965 1966- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1967 1968- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1969 1970- CFG_SCCR: System Clock and reset Control Register (15-27) 1971 1972- CFG_OR_TIMING_SDRAM: 1973 SDRAM timing 1974 1975- CFG_MAMR_PTA: 1976 periodic timer for refresh 1977 1978- CFG_DER: Debug Event Register (37-47) 1979 1980- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1981 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1982 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1983 CFG_BR1_PRELIM: 1984 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1985 1986- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1987 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1988 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1989 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1990 1991- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1992 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1993 Machine Mode Register and Memory Periodic Timer 1994 Prescaler definitions (SDRAM timing) 1995 1996- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1997 enable I2C microcode relocation patch (MPC8xx); 1998 define relocation offset in DPRAM [DSP2] 1999 2000- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 2001 enable SPI microcode relocation patch (MPC8xx); 2002 define relocation offset in DPRAM [SCC4] 2003 2004- CFG_USE_OSCCLK: 2005 Use OSCM clock mode on MBX8xx board. Be careful, 2006 wrong setting might damage your board. Read 2007 doc/README.MBX before setting this variable! 2008 2009- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 2010 Offset of the bootmode word in DPRAM used by post 2011 (Power On Self Tests). This definition overrides 2012 #define'd default value in commproc.h resp. 2013 cpm_8260.h. 2014 2015- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 2016 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 2017 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 2018 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 2019 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 2020 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 2021 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 2022 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 2023 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 2024 2025- CONFIG_ETHER_ON_FEC[12] 2026 Define to enable FEC[12] on a 8xx series processor. 2027 2028- CONFIG_FEC[12]_PHY 2029 Define to the hardcoded PHY address which corresponds 2030 to the given FEC; i. e. 2031 #define CONFIG_FEC1_PHY 4 2032 means that the PHY with address 4 is connected to FEC1 2033 2034 When set to -1, means to probe for first available. 2035 2036- CONFIG_FEC[12]_PHY_NORXERR 2037 The PHY does not have a RXERR line (RMII only). 2038 (so program the FEC to ignore it). 2039 2040- CONFIG_RMII 2041 Enable RMII mode for all FECs. 2042 Note that this is a global option, we can't 2043 have one FEC in standard MII mode and another in RMII mode. 2044 2045- CONFIG_CRC32_VERIFY 2046 Add a verify option to the crc32 command. 2047 The syntax is: 2048 2049 => crc32 -v <address> <count> <crc32> 2050 2051 Where address/count indicate a memory area 2052 and crc32 is the correct crc32 which the 2053 area should have. 2054 2055- CONFIG_LOOPW 2056 Add the "loopw" memory command. This only takes effect if 2057 the memory commands are activated globally (CFG_CMD_MEM). 2058 2059Building the Software: 2060====================== 2061 2062Building U-Boot has been tested in native PPC environments (on a 2063PowerBook G3 running LinuxPPC 2000) and in cross environments 2064(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2065NetBSD 1.5 on x86). 2066 2067If you are not using a native PPC environment, it is assumed that you 2068have the GNU cross compiling tools available in your path and named 2069with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2070you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2071the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2072change it to: 2073 2074 CROSS_COMPILE = ppc_4xx- 2075 2076 2077U-Boot is intended to be simple to build. After installing the 2078sources you must configure U-Boot for one specific board type. This 2079is done by typing: 2080 2081 make NAME_config 2082 2083where "NAME_config" is the name of one of the existing 2084configurations; the following names are supported: 2085 2086 ADCIOP_config FPS860L_config omap730p2_config 2087 ADS860_config GEN860T_config pcu_e_config 2088 AR405_config GENIETV_config PIP405_config 2089 at91rm9200dk_config GTH_config QS823_config 2090 CANBT_config hermes_config QS850_config 2091 cmi_mpc5xx_config hymod_config QS860T_config 2092 cogent_common_config IP860_config RPXlite_config 2093 cogent_mpc8260_config IVML24_config RPXlite_DW_config 2094 cogent_mpc8xx_config IVMS8_config RPXsuper_config 2095 CPCI405_config JSE_config rsdproto_config 2096 CPCIISER4_config LANTEC_config Sandpoint8240_config 2097 csb272_config lwmon_config sbc8260_config 2098 CU824_config MBX860T_config sbc8560_33_config 2099 DUET_ADS_config MBX_config sbc8560_66_config 2100 EBONY_config MPC8260ADS_config SM850_config 2101 ELPT860_config MPC8540ADS_config SPD823TS_config 2102 ESTEEM192E_config MPC8560ADS_config stxgp3_config 2103 ETX094_config NETVIA_config SXNI855T_config 2104 FADS823_config omap1510inn_config TQM823L_config 2105 FADS850SAR_config omap1610h2_config TQM850L_config 2106 FADS860T_config omap1610inn_config TQM855L_config 2107 FPS850L_config omap5912osk_config TQM860L_config 2108 WALNUT405_config 2109 ZPC1900_config 2110 2111Note: for some board special configuration names may exist; check if 2112 additional information is available from the board vendor; for 2113 instance, the TQM823L systems are available without (standard) 2114 or with LCD support. You can select such additional "features" 2115 when chosing the configuration, i. e. 2116 2117 make TQM823L_config 2118 - will configure for a plain TQM823L, i. e. no LCD support 2119 2120 make TQM823L_LCD_config 2121 - will configure for a TQM823L with U-Boot console on LCD 2122 2123 etc. 2124 2125 2126Finally, type "make all", and you should get some working U-Boot 2127images ready for download to / installation on your system: 2128 2129- "u-boot.bin" is a raw binary image 2130- "u-boot" is an image in ELF binary format 2131- "u-boot.srec" is in Motorola S-Record format 2132 2133 2134Please be aware that the Makefiles assume you are using GNU make, so 2135for instance on NetBSD you might need to use "gmake" instead of 2136native "make". 2137 2138 2139If the system board that you have is not listed, then you will need 2140to port U-Boot to your hardware platform. To do this, follow these 2141steps: 2142 21431. Add a new configuration option for your board to the toplevel 2144 "Makefile" and to the "MAKEALL" script, using the existing 2145 entries as examples. Note that here and at many other places 2146 boards and other names are listed in alphabetical sort order. Please 2147 keep this order. 21482. Create a new directory to hold your board specific code. Add any 2149 files you need. In your board directory, you will need at least 2150 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 21513. Create a new configuration file "include/configs/<board>.h" for 2152 your board 21533. If you're porting U-Boot to a new CPU, then also create a new 2154 directory to hold your CPU specific code. Add any files you need. 21554. Run "make <board>_config" with your new name. 21565. Type "make", and you should get a working "u-boot.srec" file 2157 to be installed on your target system. 21586. Debug and solve any problems that might arise. 2159 [Of course, this last step is much harder than it sounds.] 2160 2161 2162Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2163============================================================== 2164 2165If you have modified U-Boot sources (for instance added a new board 2166or support for new devices, a new CPU, etc.) you are expected to 2167provide feedback to the other developers. The feedback normally takes 2168the form of a "patch", i. e. a context diff against a certain (latest 2169official or latest in CVS) version of U-Boot sources. 2170 2171But before you submit such a patch, please verify that your modifi- 2172cation did not break existing code. At least make sure that *ALL* of 2173the supported boards compile WITHOUT ANY compiler warnings. To do so, 2174just run the "MAKEALL" script, which will configure and build U-Boot 2175for ALL supported system. Be warned, this will take a while. You can 2176select which (cross) compiler to use by passing a `CROSS_COMPILE' 2177environment variable to the script, i. e. to use the cross tools from 2178MontaVista's Hard Hat Linux you can type 2179 2180 CROSS_COMPILE=ppc_8xx- MAKEALL 2181 2182or to build on a native PowerPC system you can type 2183 2184 CROSS_COMPILE=' ' MAKEALL 2185 2186See also "U-Boot Porting Guide" below. 2187 2188 2189Monitor Commands - Overview: 2190============================ 2191 2192go - start application at address 'addr' 2193run - run commands in an environment variable 2194bootm - boot application image from memory 2195bootp - boot image via network using BootP/TFTP protocol 2196tftpboot- boot image via network using TFTP protocol 2197 and env variables "ipaddr" and "serverip" 2198 (and eventually "gatewayip") 2199rarpboot- boot image via network using RARP/TFTP protocol 2200diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2201loads - load S-Record file over serial line 2202loadb - load binary file over serial line (kermit mode) 2203md - memory display 2204mm - memory modify (auto-incrementing) 2205nm - memory modify (constant address) 2206mw - memory write (fill) 2207cp - memory copy 2208cmp - memory compare 2209crc32 - checksum calculation 2210imd - i2c memory display 2211imm - i2c memory modify (auto-incrementing) 2212inm - i2c memory modify (constant address) 2213imw - i2c memory write (fill) 2214icrc32 - i2c checksum calculation 2215iprobe - probe to discover valid I2C chip addresses 2216iloop - infinite loop on address range 2217isdram - print SDRAM configuration information 2218sspi - SPI utility commands 2219base - print or set address offset 2220printenv- print environment variables 2221setenv - set environment variables 2222saveenv - save environment variables to persistent storage 2223protect - enable or disable FLASH write protection 2224erase - erase FLASH memory 2225flinfo - print FLASH memory information 2226bdinfo - print Board Info structure 2227iminfo - print header information for application image 2228coninfo - print console devices and informations 2229ide - IDE sub-system 2230loop - infinite loop on address range 2231loopw - infinite write loop on address range 2232mtest - simple RAM test 2233icache - enable or disable instruction cache 2234dcache - enable or disable data cache 2235reset - Perform RESET of the CPU 2236echo - echo args to console 2237version - print monitor version 2238help - print online help 2239? - alias for 'help' 2240 2241 2242Monitor Commands - Detailed Description: 2243======================================== 2244 2245TODO. 2246 2247For now: just type "help <command>". 2248 2249 2250Environment Variables: 2251====================== 2252 2253U-Boot supports user configuration using Environment Variables which 2254can be made persistent by saving to Flash memory. 2255 2256Environment Variables are set using "setenv", printed using 2257"printenv", and saved to Flash using "saveenv". Using "setenv" 2258without a value can be used to delete a variable from the 2259environment. As long as you don't save the environment you are 2260working with an in-memory copy. In case the Flash area containing the 2261environment is erased by accident, a default environment is provided. 2262 2263Some configuration options can be set using Environment Variables: 2264 2265 baudrate - see CONFIG_BAUDRATE 2266 2267 bootdelay - see CONFIG_BOOTDELAY 2268 2269 bootcmd - see CONFIG_BOOTCOMMAND 2270 2271 bootargs - Boot arguments when booting an RTOS image 2272 2273 bootfile - Name of the image to load with TFTP 2274 2275 autoload - if set to "no" (any string beginning with 'n'), 2276 "bootp" will just load perform a lookup of the 2277 configuration from the BOOTP server, but not try to 2278 load any image using TFTP 2279 2280 autostart - if set to "yes", an image loaded using the "bootp", 2281 "rarpboot", "tftpboot" or "diskboot" commands will 2282 be automatically started (by internally calling 2283 "bootm") 2284 2285 If set to "no", a standalone image passed to the 2286 "bootm" command will be copied to the load address 2287 (and eventually uncompressed), but NOT be started. 2288 This can be used to load and uncompress arbitrary 2289 data. 2290 2291 i2cfast - (PPC405GP|PPC405EP only) 2292 if set to 'y' configures Linux I2C driver for fast 2293 mode (400kHZ). This environment variable is used in 2294 initialization code. So, for changes to be effective 2295 it must be saved and board must be reset. 2296 2297 initrd_high - restrict positioning of initrd images: 2298 If this variable is not set, initrd images will be 2299 copied to the highest possible address in RAM; this 2300 is usually what you want since it allows for 2301 maximum initrd size. If for some reason you want to 2302 make sure that the initrd image is loaded below the 2303 CFG_BOOTMAPSZ limit, you can set this environment 2304 variable to a value of "no" or "off" or "0". 2305 Alternatively, you can set it to a maximum upper 2306 address to use (U-Boot will still check that it 2307 does not overwrite the U-Boot stack and data). 2308 2309 For instance, when you have a system with 16 MB 2310 RAM, and want to reserve 4 MB from use by Linux, 2311 you can do this by adding "mem=12M" to the value of 2312 the "bootargs" variable. However, now you must make 2313 sure that the initrd image is placed in the first 2314 12 MB as well - this can be done with 2315 2316 setenv initrd_high 00c00000 2317 2318 If you set initrd_high to 0xFFFFFFFF, this is an 2319 indication to U-Boot that all addresses are legal 2320 for the Linux kernel, including addresses in flash 2321 memory. In this case U-Boot will NOT COPY the 2322 ramdisk at all. This may be useful to reduce the 2323 boot time on your system, but requires that this 2324 feature is supported by your Linux kernel. 2325 2326 ipaddr - IP address; needed for tftpboot command 2327 2328 loadaddr - Default load address for commands like "bootp", 2329 "rarpboot", "tftpboot", "loadb" or "diskboot" 2330 2331 loads_echo - see CONFIG_LOADS_ECHO 2332 2333 serverip - TFTP server IP address; needed for tftpboot command 2334 2335 bootretry - see CONFIG_BOOT_RETRY_TIME 2336 2337 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2338 2339 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2340 2341 ethprime - When CONFIG_NET_MULTI is enabled controls which 2342 interface is used first. 2343 2344 ethact - When CONFIG_NET_MULTI is enabled controls which 2345 interface is currently active. For example you 2346 can do the following 2347 2348 => setenv ethact FEC ETHERNET 2349 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2350 => setenv ethact SCC ETHERNET 2351 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2352 2353 netretry - When set to "no" each network operation will 2354 either succeed or fail without retrying. 2355 When set to "once" the network operation will 2356 fail when all the available network interfaces 2357 are tried once without success. 2358 Useful on scripts which control the retry operation 2359 themselves. 2360 2361 vlan - When set to a value < 4095 the traffic over 2362 ethernet is encapsulated/received over 802.1q 2363 VLAN tagged frames. 2364 2365The following environment variables may be used and automatically 2366updated by the network boot commands ("bootp" and "rarpboot"), 2367depending the information provided by your boot server: 2368 2369 bootfile - see above 2370 dnsip - IP address of your Domain Name Server 2371 dnsip2 - IP address of your secondary Domain Name Server 2372 gatewayip - IP address of the Gateway (Router) to use 2373 hostname - Target hostname 2374 ipaddr - see above 2375 netmask - Subnet Mask 2376 rootpath - Pathname of the root filesystem on the NFS server 2377 serverip - see above 2378 2379 2380There are two special Environment Variables: 2381 2382 serial# - contains hardware identification information such 2383 as type string and/or serial number 2384 ethaddr - Ethernet address 2385 2386These variables can be set only once (usually during manufacturing of 2387the board). U-Boot refuses to delete or overwrite these variables 2388once they have been set once. 2389 2390 2391Further special Environment Variables: 2392 2393 ver - Contains the U-Boot version string as printed 2394 with the "version" command. This variable is 2395 readonly (see CONFIG_VERSION_VARIABLE). 2396 2397 2398Please note that changes to some configuration parameters may take 2399only effect after the next boot (yes, that's just like Windoze :-). 2400 2401 2402Command Line Parsing: 2403===================== 2404 2405There are two different command line parsers available with U-Boot: 2406the old "simple" one, and the much more powerful "hush" shell: 2407 2408Old, simple command line parser: 2409-------------------------------- 2410 2411- supports environment variables (through setenv / saveenv commands) 2412- several commands on one line, separated by ';' 2413- variable substitution using "... $(name) ..." syntax 2414- special characters ('$', ';') can be escaped by prefixing with '\', 2415 for example: 2416 setenv bootcmd bootm \$(address) 2417- You can also escape text by enclosing in single apostrophes, for example: 2418 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2419 2420Hush shell: 2421----------- 2422 2423- similar to Bourne shell, with control structures like 2424 if...then...else...fi, for...do...done; while...do...done, 2425 until...do...done, ... 2426- supports environment ("global") variables (through setenv / saveenv 2427 commands) and local shell variables (through standard shell syntax 2428 "name=value"); only environment variables can be used with "run" 2429 command 2430 2431General rules: 2432-------------- 2433 2434(1) If a command line (or an environment variable executed by a "run" 2435 command) contains several commands separated by semicolon, and 2436 one of these commands fails, then the remaining commands will be 2437 executed anyway. 2438 2439(2) If you execute several variables with one call to run (i. e. 2440 calling run with a list af variables as arguments), any failing 2441 command will cause "run" to terminate, i. e. the remaining 2442 variables are not executed. 2443 2444Note for Redundant Ethernet Interfaces: 2445======================================= 2446 2447Some boards come with redundant ethernet interfaces; U-Boot supports 2448such configurations and is capable of automatic selection of a 2449"working" interface when needed. MAC assignment works as follows: 2450 2451Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2452MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2453"eth1addr" (=>eth1), "eth2addr", ... 2454 2455If the network interface stores some valid MAC address (for instance 2456in SROM), this is used as default address if there is NO correspon- 2457ding setting in the environment; if the corresponding environment 2458variable is set, this overrides the settings in the card; that means: 2459 2460o If the SROM has a valid MAC address, and there is no address in the 2461 environment, the SROM's address is used. 2462 2463o If there is no valid address in the SROM, and a definition in the 2464 environment exists, then the value from the environment variable is 2465 used. 2466 2467o If both the SROM and the environment contain a MAC address, and 2468 both addresses are the same, this MAC address is used. 2469 2470o If both the SROM and the environment contain a MAC address, and the 2471 addresses differ, the value from the environment is used and a 2472 warning is printed. 2473 2474o If neither SROM nor the environment contain a MAC address, an error 2475 is raised. 2476 2477 2478Image Formats: 2479============== 2480 2481The "boot" commands of this monitor operate on "image" files which 2482can be basicly anything, preceeded by a special header; see the 2483definitions in include/image.h for details; basicly, the header 2484defines the following image properties: 2485 2486* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2487 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2488 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2489 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2490* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2491 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2492 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC). 2493* Compression Type (uncompressed, gzip, bzip2) 2494* Load Address 2495* Entry Point 2496* Image Name 2497* Image Timestamp 2498 2499The header is marked by a special Magic Number, and both the header 2500and the data portions of the image are secured against corruption by 2501CRC32 checksums. 2502 2503 2504Linux Support: 2505============== 2506 2507Although U-Boot should support any OS or standalone application 2508easily, the main focus has always been on Linux during the design of 2509U-Boot. 2510 2511U-Boot includes many features that so far have been part of some 2512special "boot loader" code within the Linux kernel. Also, any 2513"initrd" images to be used are no longer part of one big Linux image; 2514instead, kernel and "initrd" are separate images. This implementation 2515serves several purposes: 2516 2517- the same features can be used for other OS or standalone 2518 applications (for instance: using compressed images to reduce the 2519 Flash memory footprint) 2520 2521- it becomes much easier to port new Linux kernel versions because 2522 lots of low-level, hardware dependent stuff are done by U-Boot 2523 2524- the same Linux kernel image can now be used with different "initrd" 2525 images; of course this also means that different kernel images can 2526 be run with the same "initrd". This makes testing easier (you don't 2527 have to build a new "zImage.initrd" Linux image when you just 2528 change a file in your "initrd"). Also, a field-upgrade of the 2529 software is easier now. 2530 2531 2532Linux HOWTO: 2533============ 2534 2535Porting Linux to U-Boot based systems: 2536--------------------------------------- 2537 2538U-Boot cannot save you from doing all the necessary modifications to 2539configure the Linux device drivers for use with your target hardware 2540(no, we don't intend to provide a full virtual machine interface to 2541Linux :-). 2542 2543But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2544 2545Just make sure your machine specific header file (for instance 2546include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2547Information structure as we define in include/u-boot.h, and make 2548sure that your definition of IMAP_ADDR uses the same value as your 2549U-Boot configuration in CFG_IMMR. 2550 2551 2552Configuring the Linux kernel: 2553----------------------------- 2554 2555No specific requirements for U-Boot. Make sure you have some root 2556device (initial ramdisk, NFS) for your target system. 2557 2558 2559Building a Linux Image: 2560----------------------- 2561 2562With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2563not used. If you use recent kernel source, a new build target 2564"uImage" will exist which automatically builds an image usable by 2565U-Boot. Most older kernels also have support for a "pImage" target, 2566which was introduced for our predecessor project PPCBoot and uses a 2567100% compatible format. 2568 2569Example: 2570 2571 make TQM850L_config 2572 make oldconfig 2573 make dep 2574 make uImage 2575 2576The "uImage" build target uses a special tool (in 'tools/mkimage') to 2577encapsulate a compressed Linux kernel image with header information, 2578CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2579 2580* build a standard "vmlinux" kernel image (in ELF binary format): 2581 2582* convert the kernel into a raw binary image: 2583 2584 ${CROSS_COMPILE}-objcopy -O binary \ 2585 -R .note -R .comment \ 2586 -S vmlinux linux.bin 2587 2588* compress the binary image: 2589 2590 gzip -9 linux.bin 2591 2592* package compressed binary image for U-Boot: 2593 2594 mkimage -A ppc -O linux -T kernel -C gzip \ 2595 -a 0 -e 0 -n "Linux Kernel Image" \ 2596 -d linux.bin.gz uImage 2597 2598 2599The "mkimage" tool can also be used to create ramdisk images for use 2600with U-Boot, either separated from the Linux kernel image, or 2601combined into one file. "mkimage" encapsulates the images with a 64 2602byte header containing information about target architecture, 2603operating system, image type, compression method, entry points, time 2604stamp, CRC32 checksums, etc. 2605 2606"mkimage" can be called in two ways: to verify existing images and 2607print the header information, or to build new images. 2608 2609In the first form (with "-l" option) mkimage lists the information 2610contained in the header of an existing U-Boot image; this includes 2611checksum verification: 2612 2613 tools/mkimage -l image 2614 -l ==> list image header information 2615 2616The second form (with "-d" option) is used to build a U-Boot image 2617from a "data file" which is used as image payload: 2618 2619 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2620 -n name -d data_file image 2621 -A ==> set architecture to 'arch' 2622 -O ==> set operating system to 'os' 2623 -T ==> set image type to 'type' 2624 -C ==> set compression type 'comp' 2625 -a ==> set load address to 'addr' (hex) 2626 -e ==> set entry point to 'ep' (hex) 2627 -n ==> set image name to 'name' 2628 -d ==> use image data from 'datafile' 2629 2630Right now, all Linux kernels for PowerPC systems use the same load 2631address (0x00000000), but the entry point address depends on the 2632kernel version: 2633 2634- 2.2.x kernels have the entry point at 0x0000000C, 2635- 2.3.x and later kernels have the entry point at 0x00000000. 2636 2637So a typical call to build a U-Boot image would read: 2638 2639 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2640 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2641 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2642 > examples/uImage.TQM850L 2643 Image Name: 2.4.4 kernel for TQM850L 2644 Created: Wed Jul 19 02:34:59 2000 2645 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2646 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2647 Load Address: 0x00000000 2648 Entry Point: 0x00000000 2649 2650To verify the contents of the image (or check for corruption): 2651 2652 -> tools/mkimage -l examples/uImage.TQM850L 2653 Image Name: 2.4.4 kernel for TQM850L 2654 Created: Wed Jul 19 02:34:59 2000 2655 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2656 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2657 Load Address: 0x00000000 2658 Entry Point: 0x00000000 2659 2660NOTE: for embedded systems where boot time is critical you can trade 2661speed for memory and install an UNCOMPRESSED image instead: this 2662needs more space in Flash, but boots much faster since it does not 2663need to be uncompressed: 2664 2665 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2666 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2667 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2668 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2669 > examples/uImage.TQM850L-uncompressed 2670 Image Name: 2.4.4 kernel for TQM850L 2671 Created: Wed Jul 19 02:34:59 2000 2672 Image Type: PowerPC Linux Kernel Image (uncompressed) 2673 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2674 Load Address: 0x00000000 2675 Entry Point: 0x00000000 2676 2677 2678Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2679when your kernel is intended to use an initial ramdisk: 2680 2681 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2682 > -A ppc -O linux -T ramdisk -C gzip \ 2683 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2684 Image Name: Simple Ramdisk Image 2685 Created: Wed Jan 12 14:01:50 2000 2686 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2687 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2688 Load Address: 0x00000000 2689 Entry Point: 0x00000000 2690 2691 2692Installing a Linux Image: 2693------------------------- 2694 2695To downloading a U-Boot image over the serial (console) interface, 2696you must convert the image to S-Record format: 2697 2698 objcopy -I binary -O srec examples/image examples/image.srec 2699 2700The 'objcopy' does not understand the information in the U-Boot 2701image header, so the resulting S-Record file will be relative to 2702address 0x00000000. To load it to a given address, you need to 2703specify the target address as 'offset' parameter with the 'loads' 2704command. 2705 2706Example: install the image to address 0x40100000 (which on the 2707TQM8xxL is in the first Flash bank): 2708 2709 => erase 40100000 401FFFFF 2710 2711 .......... done 2712 Erased 8 sectors 2713 2714 => loads 40100000 2715 ## Ready for S-Record download ... 2716 ~>examples/image.srec 2717 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2718 ... 2719 15989 15990 15991 15992 2720 [file transfer complete] 2721 [connected] 2722 ## Start Addr = 0x00000000 2723 2724 2725You can check the success of the download using the 'iminfo' command; 2726this includes a checksum verification so you can be sure no data 2727corruption happened: 2728 2729 => imi 40100000 2730 2731 ## Checking Image at 40100000 ... 2732 Image Name: 2.2.13 for initrd on TQM850L 2733 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2734 Data Size: 335725 Bytes = 327 kB = 0 MB 2735 Load Address: 00000000 2736 Entry Point: 0000000c 2737 Verifying Checksum ... OK 2738 2739 2740Boot Linux: 2741----------- 2742 2743The "bootm" command is used to boot an application that is stored in 2744memory (RAM or Flash). In case of a Linux kernel image, the contents 2745of the "bootargs" environment variable is passed to the kernel as 2746parameters. You can check and modify this variable using the 2747"printenv" and "setenv" commands: 2748 2749 2750 => printenv bootargs 2751 bootargs=root=/dev/ram 2752 2753 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2754 2755 => printenv bootargs 2756 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2757 2758 => bootm 40020000 2759 ## Booting Linux kernel at 40020000 ... 2760 Image Name: 2.2.13 for NFS on TQM850L 2761 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2762 Data Size: 381681 Bytes = 372 kB = 0 MB 2763 Load Address: 00000000 2764 Entry Point: 0000000c 2765 Verifying Checksum ... OK 2766 Uncompressing Kernel Image ... OK 2767 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 2768 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2769 time_init: decrementer frequency = 187500000/60 2770 Calibrating delay loop... 49.77 BogoMIPS 2771 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2772 ... 2773 2774If you want to boot a Linux kernel with initial ram disk, you pass 2775the memory addresses of both the kernel and the initrd image (PPBCOOT 2776format!) to the "bootm" command: 2777 2778 => imi 40100000 40200000 2779 2780 ## Checking Image at 40100000 ... 2781 Image Name: 2.2.13 for initrd on TQM850L 2782 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2783 Data Size: 335725 Bytes = 327 kB = 0 MB 2784 Load Address: 00000000 2785 Entry Point: 0000000c 2786 Verifying Checksum ... OK 2787 2788 ## Checking Image at 40200000 ... 2789 Image Name: Simple Ramdisk Image 2790 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2791 Data Size: 566530 Bytes = 553 kB = 0 MB 2792 Load Address: 00000000 2793 Entry Point: 00000000 2794 Verifying Checksum ... OK 2795 2796 => bootm 40100000 40200000 2797 ## Booting Linux kernel at 40100000 ... 2798 Image Name: 2.2.13 for initrd on TQM850L 2799 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2800 Data Size: 335725 Bytes = 327 kB = 0 MB 2801 Load Address: 00000000 2802 Entry Point: 0000000c 2803 Verifying Checksum ... OK 2804 Uncompressing Kernel Image ... OK 2805 ## Loading RAMDisk Image at 40200000 ... 2806 Image Name: Simple Ramdisk Image 2807 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2808 Data Size: 566530 Bytes = 553 kB = 0 MB 2809 Load Address: 00000000 2810 Entry Point: 00000000 2811 Verifying Checksum ... OK 2812 Loading Ramdisk ... OK 2813 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 2814 Boot arguments: root=/dev/ram 2815 time_init: decrementer frequency = 187500000/60 2816 Calibrating delay loop... 49.77 BogoMIPS 2817 ... 2818 RAMDISK: Compressed image found at block 0 2819 VFS: Mounted root (ext2 filesystem). 2820 2821 bash# 2822 2823More About U-Boot Image Types: 2824------------------------------ 2825 2826U-Boot supports the following image types: 2827 2828 "Standalone Programs" are directly runnable in the environment 2829 provided by U-Boot; it is expected that (if they behave 2830 well) you can continue to work in U-Boot after return from 2831 the Standalone Program. 2832 "OS Kernel Images" are usually images of some Embedded OS which 2833 will take over control completely. Usually these programs 2834 will install their own set of exception handlers, device 2835 drivers, set up the MMU, etc. - this means, that you cannot 2836 expect to re-enter U-Boot except by resetting the CPU. 2837 "RAMDisk Images" are more or less just data blocks, and their 2838 parameters (address, size) are passed to an OS kernel that is 2839 being started. 2840 "Multi-File Images" contain several images, typically an OS 2841 (Linux) kernel image and one or more data images like 2842 RAMDisks. This construct is useful for instance when you want 2843 to boot over the network using BOOTP etc., where the boot 2844 server provides just a single image file, but you want to get 2845 for instance an OS kernel and a RAMDisk image. 2846 2847 "Multi-File Images" start with a list of image sizes, each 2848 image size (in bytes) specified by an "uint32_t" in network 2849 byte order. This list is terminated by an "(uint32_t)0". 2850 Immediately after the terminating 0 follow the images, one by 2851 one, all aligned on "uint32_t" boundaries (size rounded up to 2852 a multiple of 4 bytes). 2853 2854 "Firmware Images" are binary images containing firmware (like 2855 U-Boot or FPGA images) which usually will be programmed to 2856 flash memory. 2857 2858 "Script files" are command sequences that will be executed by 2859 U-Boot's command interpreter; this feature is especially 2860 useful when you configure U-Boot to use a real shell (hush) 2861 as command interpreter. 2862 2863 2864Standalone HOWTO: 2865================= 2866 2867One of the features of U-Boot is that you can dynamically load and 2868run "standalone" applications, which can use some resources of 2869U-Boot like console I/O functions or interrupt services. 2870 2871Two simple examples are included with the sources: 2872 2873"Hello World" Demo: 2874------------------- 2875 2876'examples/hello_world.c' contains a small "Hello World" Demo 2877application; it is automatically compiled when you build U-Boot. 2878It's configured to run at address 0x00040004, so you can play with it 2879like that: 2880 2881 => loads 2882 ## Ready for S-Record download ... 2883 ~>examples/hello_world.srec 2884 1 2 3 4 5 6 7 8 9 10 11 ... 2885 [file transfer complete] 2886 [connected] 2887 ## Start Addr = 0x00040004 2888 2889 => go 40004 Hello World! This is a test. 2890 ## Starting application at 0x00040004 ... 2891 Hello World 2892 argc = 7 2893 argv[0] = "40004" 2894 argv[1] = "Hello" 2895 argv[2] = "World!" 2896 argv[3] = "This" 2897 argv[4] = "is" 2898 argv[5] = "a" 2899 argv[6] = "test." 2900 argv[7] = "<NULL>" 2901 Hit any key to exit ... 2902 2903 ## Application terminated, rc = 0x0 2904 2905Another example, which demonstrates how to register a CPM interrupt 2906handler with the U-Boot code, can be found in 'examples/timer.c'. 2907Here, a CPM timer is set up to generate an interrupt every second. 2908The interrupt service routine is trivial, just printing a '.' 2909character, but this is just a demo program. The application can be 2910controlled by the following keys: 2911 2912 ? - print current values og the CPM Timer registers 2913 b - enable interrupts and start timer 2914 e - stop timer and disable interrupts 2915 q - quit application 2916 2917 => loads 2918 ## Ready for S-Record download ... 2919 ~>examples/timer.srec 2920 1 2 3 4 5 6 7 8 9 10 11 ... 2921 [file transfer complete] 2922 [connected] 2923 ## Start Addr = 0x00040004 2924 2925 => go 40004 2926 ## Starting application at 0x00040004 ... 2927 TIMERS=0xfff00980 2928 Using timer 1 2929 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2930 2931Hit 'b': 2932 [q, b, e, ?] Set interval 1000000 us 2933 Enabling timer 2934Hit '?': 2935 [q, b, e, ?] ........ 2936 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2937Hit '?': 2938 [q, b, e, ?] . 2939 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2940Hit '?': 2941 [q, b, e, ?] . 2942 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2943Hit '?': 2944 [q, b, e, ?] . 2945 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2946Hit 'e': 2947 [q, b, e, ?] ...Stopping timer 2948Hit 'q': 2949 [q, b, e, ?] ## Application terminated, rc = 0x0 2950 2951 2952Minicom warning: 2953================ 2954 2955Over time, many people have reported problems when trying to use the 2956"minicom" terminal emulation program for serial download. I (wd) 2957consider minicom to be broken, and recommend not to use it. Under 2958Unix, I recommend to use C-Kermit for general purpose use (and 2959especially for kermit binary protocol download ("loadb" command), and 2960use "cu" for S-Record download ("loads" command). 2961 2962Nevertheless, if you absolutely want to use it try adding this 2963configuration to your "File transfer protocols" section: 2964 2965 Name Program Name U/D FullScr IO-Red. Multi 2966 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2967 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2968 2969 2970NetBSD Notes: 2971============= 2972 2973Starting at version 0.9.2, U-Boot supports NetBSD both as host 2974(build U-Boot) and target system (boots NetBSD/mpc8xx). 2975 2976Building requires a cross environment; it is known to work on 2977NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2978need gmake since the Makefiles are not compatible with BSD make). 2979Note that the cross-powerpc package does not install include files; 2980attempting to build U-Boot will fail because <machine/ansi.h> is 2981missing. This file has to be installed and patched manually: 2982 2983 # cd /usr/pkg/cross/powerpc-netbsd/include 2984 # mkdir powerpc 2985 # ln -s powerpc machine 2986 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2987 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2988 2989Native builds *don't* work due to incompatibilities between native 2990and U-Boot include files. 2991 2992Booting assumes that (the first part of) the image booted is a 2993stage-2 loader which in turn loads and then invokes the kernel 2994proper. Loader sources will eventually appear in the NetBSD source 2995tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2996meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2997details. 2998 2999 3000Implementation Internals: 3001========================= 3002 3003The following is not intended to be a complete description of every 3004implementation detail. However, it should help to understand the 3005inner workings of U-Boot and make it easier to port it to custom 3006hardware. 3007 3008 3009Initial Stack, Global Data: 3010--------------------------- 3011 3012The implementation of U-Boot is complicated by the fact that U-Boot 3013starts running out of ROM (flash memory), usually without access to 3014system RAM (because the memory controller is not initialized yet). 3015This means that we don't have writable Data or BSS segments, and BSS 3016is not initialized as zero. To be able to get a C environment working 3017at all, we have to allocate at least a minimal stack. Implementation 3018options for this are defined and restricted by the CPU used: Some CPU 3019models provide on-chip memory (like the IMMR area on MPC8xx and 3020MPC826x processors), on others (parts of) the data cache can be 3021locked as (mis-) used as memory, etc. 3022 3023 Chris Hallinan posted a good summary of these issues to the 3024 u-boot-users mailing list: 3025 3026 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 3027 From: "Chris Hallinan" <clh@net1plus.com> 3028 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 3029 ... 3030 3031 Correct me if I'm wrong, folks, but the way I understand it 3032 is this: Using DCACHE as initial RAM for Stack, etc, does not 3033 require any physical RAM backing up the cache. The cleverness 3034 is that the cache is being used as a temporary supply of 3035 necessary storage before the SDRAM controller is setup. It's 3036 beyond the scope of this list to expain the details, but you 3037 can see how this works by studying the cache architecture and 3038 operation in the architecture and processor-specific manuals. 3039 3040 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3041 is another option for the system designer to use as an 3042 initial stack/ram area prior to SDRAM being available. Either 3043 option should work for you. Using CS 4 should be fine if your 3044 board designers haven't used it for something that would 3045 cause you grief during the initial boot! It is frequently not 3046 used. 3047 3048 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3049 with your processor/board/system design. The default value 3050 you will find in any recent u-boot distribution in 3051 Walnut405.h should work for you. I'd set it to a value larger 3052 than your SDRAM module. If you have a 64MB SDRAM module, set 3053 it above 400_0000. Just make sure your board has no resources 3054 that are supposed to respond to that address! That code in 3055 start.S has been around a while and should work as is when 3056 you get the config right. 3057 3058 -Chris Hallinan 3059 DS4.COM, Inc. 3060 3061It is essential to remember this, since it has some impact on the C 3062code for the initialization procedures: 3063 3064* Initialized global data (data segment) is read-only. Do not attempt 3065 to write it. 3066 3067* Do not use any unitialized global data (or implicitely initialized 3068 as zero data - BSS segment) at all - this is undefined, initiali- 3069 zation is performed later (when relocating to RAM). 3070 3071* Stack space is very limited. Avoid big data buffers or things like 3072 that. 3073 3074Having only the stack as writable memory limits means we cannot use 3075normal global data to share information beween the code. But it 3076turned out that the implementation of U-Boot can be greatly 3077simplified by making a global data structure (gd_t) available to all 3078functions. We could pass a pointer to this data as argument to _all_ 3079functions, but this would bloat the code. Instead we use a feature of 3080the GCC compiler (Global Register Variables) to share the data: we 3081place a pointer (gd) to the global data into a register which we 3082reserve for this purpose. 3083 3084When choosing a register for such a purpose we are restricted by the 3085relevant (E)ABI specifications for the current architecture, and by 3086GCC's implementation. 3087 3088For PowerPC, the following registers have specific use: 3089 R1: stack pointer 3090 R2: TOC pointer 3091 R3-R4: parameter passing and return values 3092 R5-R10: parameter passing 3093 R13: small data area pointer 3094 R30: GOT pointer 3095 R31: frame pointer 3096 3097 (U-Boot also uses R14 as internal GOT pointer.) 3098 3099 ==> U-Boot will use R29 to hold a pointer to the global data 3100 3101 Note: on PPC, we could use a static initializer (since the 3102 address of the global data structure is known at compile time), 3103 but it turned out that reserving a register results in somewhat 3104 smaller code - although the code savings are not that big (on 3105 average for all boards 752 bytes for the whole U-Boot image, 3106 624 text + 127 data). 3107 3108On ARM, the following registers are used: 3109 3110 R0: function argument word/integer result 3111 R1-R3: function argument word 3112 R9: GOT pointer 3113 R10: stack limit (used only if stack checking if enabled) 3114 R11: argument (frame) pointer 3115 R12: temporary workspace 3116 R13: stack pointer 3117 R14: link register 3118 R15: program counter 3119 3120 ==> U-Boot will use R8 to hold a pointer to the global data 3121 3122 3123Memory Management: 3124------------------ 3125 3126U-Boot runs in system state and uses physical addresses, i.e. the 3127MMU is not used either for address mapping nor for memory protection. 3128 3129The available memory is mapped to fixed addresses using the memory 3130controller. In this process, a contiguous block is formed for each 3131memory type (Flash, SDRAM, SRAM), even when it consists of several 3132physical memory banks. 3133 3134U-Boot is installed in the first 128 kB of the first Flash bank (on 3135TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3136booting and sizing and initializing DRAM, the code relocates itself 3137to the upper end of DRAM. Immediately below the U-Boot code some 3138memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3139configuration setting]. Below that, a structure with global Board 3140Info data is placed, followed by the stack (growing downward). 3141 3142Additionally, some exception handler code is copied to the low 8 kB 3143of DRAM (0x00000000 ... 0x00001FFF). 3144 3145So a typical memory configuration with 16 MB of DRAM could look like 3146this: 3147 3148 0x0000 0000 Exception Vector code 3149 : 3150 0x0000 1FFF 3151 0x0000 2000 Free for Application Use 3152 : 3153 : 3154 3155 : 3156 : 3157 0x00FB FF20 Monitor Stack (Growing downward) 3158 0x00FB FFAC Board Info Data and permanent copy of global data 3159 0x00FC 0000 Malloc Arena 3160 : 3161 0x00FD FFFF 3162 0x00FE 0000 RAM Copy of Monitor Code 3163 ... eventually: LCD or video framebuffer 3164 ... eventually: pRAM (Protected RAM - unchanged by reset) 3165 0x00FF FFFF [End of RAM] 3166 3167 3168System Initialization: 3169---------------------- 3170 3171In the reset configuration, U-Boot starts at the reset entry point 3172(on most PowerPC systens at address 0x00000100). Because of the reset 3173configuration for CS0# this is a mirror of the onboard Flash memory. 3174To be able to re-map memory U-Boot then jumps to its link address. 3175To be able to implement the initialization code in C, a (small!) 3176initial stack is set up in the internal Dual Ported RAM (in case CPUs 3177which provide such a feature like MPC8xx or MPC8260), or in a locked 3178part of the data cache. After that, U-Boot initializes the CPU core, 3179the caches and the SIU. 3180 3181Next, all (potentially) available memory banks are mapped using a 3182preliminary mapping. For example, we put them on 512 MB boundaries 3183(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3184on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3185programmed for SDRAM access. Using the temporary configuration, a 3186simple memory test is run that determines the size of the SDRAM 3187banks. 3188 3189When there is more than one SDRAM bank, and the banks are of 3190different size, the largest is mapped first. For equal size, the first 3191bank (CS2#) is mapped first. The first mapping is always for address 31920x00000000, with any additional banks following immediately to create 3193contiguous memory starting from 0. 3194 3195Then, the monitor installs itself at the upper end of the SDRAM area 3196and allocates memory for use by malloc() and for the global Board 3197Info data; also, the exception vector code is copied to the low RAM 3198pages, and the final stack is set up. 3199 3200Only after this relocation will you have a "normal" C environment; 3201until that you are restricted in several ways, mostly because you are 3202running from ROM, and because the code will have to be relocated to a 3203new address in RAM. 3204 3205 3206U-Boot Porting Guide: 3207---------------------- 3208 3209[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3210list, October 2002] 3211 3212 3213int main (int argc, char *argv[]) 3214{ 3215 sighandler_t no_more_time; 3216 3217 signal (SIGALRM, no_more_time); 3218 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3219 3220 if (available_money > available_manpower) { 3221 pay consultant to port U-Boot; 3222 return 0; 3223 } 3224 3225 Download latest U-Boot source; 3226 3227 Subscribe to u-boot-users mailing list; 3228 3229 if (clueless) { 3230 email ("Hi, I am new to U-Boot, how do I get started?"); 3231 } 3232 3233 while (learning) { 3234 Read the README file in the top level directory; 3235 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3236 Read the source, Luke; 3237 } 3238 3239 if (available_money > toLocalCurrency ($2500)) { 3240 Buy a BDI2000; 3241 } else { 3242 Add a lot of aggravation and time; 3243 } 3244 3245 Create your own board support subdirectory; 3246 3247 Create your own board config file; 3248 3249 while (!running) { 3250 do { 3251 Add / modify source code; 3252 } until (compiles); 3253 Debug; 3254 if (clueless) 3255 email ("Hi, I am having problems..."); 3256 } 3257 Send patch file to Wolfgang; 3258 3259 return 0; 3260} 3261 3262void no_more_time (int sig) 3263{ 3264 hire_a_guru(); 3265} 3266 3267 3268Coding Standards: 3269----------------- 3270 3271All contributions to U-Boot should conform to the Linux kernel 3272coding style; see the file "Documentation/CodingStyle" in your Linux 3273kernel source directory. 3274 3275Please note that U-Boot is implemented in C (and to some small parts 3276in Assembler); no C++ is used, so please do not use C++ style 3277comments (//) in your code. 3278 3279Please also stick to the following formatting rules: 3280- remove any trailing white space 3281- use TAB characters for indentation, not spaces 3282- make sure NOT to use DOS '\r\n' line feeds 3283- do not add more than 2 empty lines to source files 3284- do not add trailing empty lines to source files 3285 3286Submissions which do not conform to the standards may be returned 3287with a request to reformat the changes. 3288 3289 3290Submitting Patches: 3291------------------- 3292 3293Since the number of patches for U-Boot is growing, we need to 3294establish some rules. Submissions which do not conform to these rules 3295may be rejected, even when they contain important and valuable stuff. 3296 3297 3298When you send a patch, please include the following information with 3299it: 3300 3301* For bug fixes: a description of the bug and how your patch fixes 3302 this bug. Please try to include a way of demonstrating that the 3303 patch actually fixes something. 3304 3305* For new features: a description of the feature and your 3306 implementation. 3307 3308* A CHANGELOG entry as plaintext (separate from the patch) 3309 3310* For major contributions, your entry to the CREDITS file 3311 3312* When you add support for a new board, don't forget to add this 3313 board to the MAKEALL script, too. 3314 3315* If your patch adds new configuration options, don't forget to 3316 document these in the README file. 3317 3318* The patch itself. If you are accessing the CVS repository use "cvs 3319 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3320 version of diff does not support these options, then get the latest 3321 version of GNU diff. 3322 3323 The current directory when running this command shall be the top 3324 level directory of the U-Boot source tree, or it's parent directory 3325 (i. e. please make sure that your patch includes sufficient 3326 directory information for the affected files). 3327 3328 We accept patches as plain text, MIME attachments or as uuencoded 3329 gzipped text. 3330 3331* If one logical set of modifications affects or creates several 3332 files, all these changes shall be submitted in a SINGLE patch file. 3333 3334* Changesets that contain different, unrelated modifications shall be 3335 submitted as SEPARATE patches, one patch per changeset. 3336 3337 3338Notes: 3339 3340* Before sending the patch, run the MAKEALL script on your patched 3341 source tree and make sure that no errors or warnings are reported 3342 for any of the boards. 3343 3344* Keep your modifications to the necessary minimum: A patch 3345 containing several unrelated changes or arbitrary reformats will be 3346 returned with a request to re-formatting / split it. 3347 3348* If you modify existing code, make sure that your new code does not 3349 add to the memory footprint of the code ;-) Small is beautiful! 3350 When adding new features, these should compile conditionally only 3351 (using #ifdef), and the resulting code with the new feature 3352 disabled must not need more memory than the old code without your 3353 modification. 3354