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_MICROBLZE 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_SM850 273 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS 274 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3 275 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T 276 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L 277 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260 278 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L 279 CONFIG_ep8260 CONFIG_MPC8560ADS CONFIG_TQM855L 280 CONFIG_ERIC CONFIG_MUSENKI CONFIG_TQM860L 281 CONFIG_ESTEEM192E CONFIG_MVS1 CONFIG_TTTech 282 CONFIG_ETX094 CONFIG_NETPHONE CONFIG_UTX8245 283 CONFIG_EVB64260 CONFIG_NETTA CONFIG_V37 284 CONFIG_FADS823 CONFIG_NETVIA CONFIG_W7OLMC 285 CONFIG_FADS850SAR CONFIG_NX823 CONFIG_W7OLMG 286 CONFIG_FADS860T CONFIG_OCRTC CONFIG_WALNUT405 287 CONFIG_FLAGADM CONFIG_ORSG CONFIG_ZPC1900 288 CONFIG_FPS850L CONFIG_OXC CONFIG_ZUMA 289 CONFIG_FPS860L 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, 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 655 656 Note that if the RTC uses I2C, then the I2C interface 657 must also be configured. See I2C Support, below. 658 659- Timestamp Support: 660 661 When CONFIG_TIMESTAMP is selected, the timestamp 662 (date and time) of an image is printed by image 663 commands like bootm or iminfo. This option is 664 automatically enabled when you select CFG_CMD_DATE . 665 666- Partition Support: 667 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 668 and/or CONFIG_ISO_PARTITION 669 670 If IDE or SCSI support is enabled (CFG_CMD_IDE or 671 CFG_CMD_SCSI) you must configure support for at least 672 one partition type as well. 673 674- IDE Reset method: 675 CONFIG_IDE_RESET_ROUTINE - this is defined in several 676 board configurations files but used nowhere! 677 678 CONFIG_IDE_RESET - is this is defined, IDE Reset will 679 be performed by calling the function 680 ide_set_reset(int reset) 681 which has to be defined in a board specific file 682 683- ATAPI Support: 684 CONFIG_ATAPI 685 686 Set this to enable ATAPI support. 687 688- LBA48 Support 689 CONFIG_LBA48 690 691 Set this to enable support for disks larger than 137GB 692 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 693 Whithout these , LBA48 support uses 32bit variables and will 'only' 694 support disks up to 2.1TB. 695 696 CFG_64BIT_LBA: 697 When enabled, makes the IDE subsystem use 64bit sector addresses. 698 Default is 32bit. 699 700- SCSI Support: 701 At the moment only there is only support for the 702 SYM53C8XX SCSI controller; define 703 CONFIG_SCSI_SYM53C8XX to enable it. 704 705 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 706 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 707 CFG_SCSI_MAX_LUN] can be adjusted to define the 708 maximum numbers of LUNs, SCSI ID's and target 709 devices. 710 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 711 712- NETWORK Support (PCI): 713 CONFIG_E1000 714 Support for Intel 8254x gigabit chips. 715 716 CONFIG_EEPRO100 717 Support for Intel 82557/82559/82559ER chips. 718 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 719 write routine for first time initialisation. 720 721 CONFIG_TULIP 722 Support for Digital 2114x chips. 723 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 724 modem chip initialisation (KS8761/QS6611). 725 726 CONFIG_NATSEMI 727 Support for National dp83815 chips. 728 729 CONFIG_NS8382X 730 Support for National dp8382[01] gigabit chips. 731 732- NETWORK Support (other): 733 734 CONFIG_DRIVER_LAN91C96 735 Support for SMSC's LAN91C96 chips. 736 737 CONFIG_LAN91C96_BASE 738 Define this to hold the physical address 739 of the LAN91C96's I/O space 740 741 CONFIG_LAN91C96_USE_32_BIT 742 Define this to enable 32 bit addressing 743 744 CONFIG_DRIVER_SMC91111 745 Support for SMSC's LAN91C111 chip 746 747 CONFIG_SMC91111_BASE 748 Define this to hold the physical address 749 of the device (I/O space) 750 751 CONFIG_SMC_USE_32_BIT 752 Define this if data bus is 32 bits 753 754 CONFIG_SMC_USE_IOFUNCS 755 Define this to use i/o functions instead of macros 756 (some hardware wont work with macros) 757 758- USB Support: 759 At the moment only the UHCI host controller is 760 supported (PIP405, MIP405, MPC5200); define 761 CONFIG_USB_UHCI to enable it. 762 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 763 end define CONFIG_USB_STORAGE to enable the USB 764 storage devices. 765 Note: 766 Supported are USB Keyboards and USB Floppy drives 767 (TEAC FD-05PUB). 768 MPC5200 USB requires additional defines: 769 CONFIG_USB_CLOCK 770 for 528 MHz Clock: 0x0001bbbb 771 CONFIG_USB_CONFIG 772 for differential drivers: 0x00001000 773 for single ended drivers: 0x00005000 774 775 776- MMC Support: 777 The MMC controller on the Intel PXA is supported. To 778 enable this define CONFIG_MMC. The MMC can be 779 accessed from the boot prompt by mapping the device 780 to physical memory similar to flash. Command line is 781 enabled with CFG_CMD_MMC. The MMC driver also works with 782 the FAT fs. This is enabled with CFG_CMD_FAT. 783 784- Keyboard Support: 785 CONFIG_ISA_KEYBOARD 786 787 Define this to enable standard (PC-Style) keyboard 788 support 789 790 CONFIG_I8042_KBD 791 Standard PC keyboard driver with US (is default) and 792 GERMAN key layout (switch via environment 'keymap=de') support. 793 Export function i8042_kbd_init, i8042_tstc and i8042_getc 794 for cfb_console. Supports cursor blinking. 795 796- Video support: 797 CONFIG_VIDEO 798 799 Define this to enable video support (for output to 800 video). 801 802 CONFIG_VIDEO_CT69000 803 804 Enable Chips & Technologies 69000 Video chip 805 806 CONFIG_VIDEO_SMI_LYNXEM 807 Enable Silicon Motion SMI 712/710/810 Video chip. The 808 video output is selected via environment 'videoout' 809 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 810 assumed. 811 812 For the CT69000 and SMI_LYNXEM drivers, videomode is 813 selected via environment 'videomode'. Two diferent ways 814 are possible: 815 - "videomode=num" 'num' is a standard LiLo mode numbers. 816 Following standard modes are supported (* is default): 817 818 Colors 640x480 800x600 1024x768 1152x864 1280x1024 819 -------------+--------------------------------------------- 820 8 bits | 0x301* 0x303 0x305 0x161 0x307 821 15 bits | 0x310 0x313 0x316 0x162 0x319 822 16 bits | 0x311 0x314 0x317 0x163 0x31A 823 24 bits | 0x312 0x315 0x318 ? 0x31B 824 -------------+--------------------------------------------- 825 (i.e. setenv videomode 317; saveenv; reset;) 826 827 - "videomode=bootargs" all the video parameters are parsed 828 from the bootargs. (See drivers/videomodes.c) 829 830 831 CONFIG_VIDEO_SED13806 832 Enable Epson SED13806 driver. This driver supports 8bpp 833 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 834 or CONFIG_VIDEO_SED13806_16BPP 835 836- Keyboard Support: 837 CONFIG_KEYBOARD 838 839 Define this to enable a custom keyboard support. 840 This simply calls drv_keyboard_init() which must be 841 defined in your board-specific files. 842 The only board using this so far is RBC823. 843 844- LCD Support: CONFIG_LCD 845 846 Define this to enable LCD support (for output to LCD 847 display); also select one of the supported displays 848 by defining one of these: 849 850 CONFIG_NEC_NL6448AC33: 851 852 NEC NL6448AC33-18. Active, color, single scan. 853 854 CONFIG_NEC_NL6448BC20 855 856 NEC NL6448BC20-08. 6.5", 640x480. 857 Active, color, single scan. 858 859 CONFIG_NEC_NL6448BC33_54 860 861 NEC NL6448BC33-54. 10.4", 640x480. 862 Active, color, single scan. 863 864 CONFIG_SHARP_16x9 865 866 Sharp 320x240. Active, color, single scan. 867 It isn't 16x9, and I am not sure what it is. 868 869 CONFIG_SHARP_LQ64D341 870 871 Sharp LQ64D341 display, 640x480. 872 Active, color, single scan. 873 874 CONFIG_HLD1045 875 876 HLD1045 display, 640x480. 877 Active, color, single scan. 878 879 CONFIG_OPTREX_BW 880 881 Optrex CBL50840-2 NF-FW 99 22 M5 882 or 883 Hitachi LMG6912RPFC-00T 884 or 885 Hitachi SP14Q002 886 887 320x240. Black & white. 888 889 Normally display is black on white background; define 890 CFG_WHITE_ON_BLACK to get it inverted. 891 892- Splash Screen Support: CONFIG_SPLASH_SCREEN 893 894 If this option is set, the environment is checked for 895 a variable "splashimage". If found, the usual display 896 of logo, copyright and system information on the LCD 897 is supressed and the BMP image at the address 898 specified in "splashimage" is loaded instead. The 899 console is redirected to the "nulldev", too. This 900 allows for a "silent" boot where a splash screen is 901 loaded very quickly after power-on. 902 903- Compression support: 904 CONFIG_BZIP2 905 906 If this option is set, support for bzip2 compressed 907 images is included. If not, only uncompressed and gzip 908 compressed images are supported. 909 910 NOTE: the bzip2 algorithm requires a lot of RAM, so 911 the malloc area (as defined by CFG_MALLOC_LEN) should 912 be at least 4MB. 913 914- MII/PHY support: 915 CONFIG_PHY_ADDR 916 917 The address of PHY on MII bus. 918 919 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 920 921 The clock frequency of the MII bus 922 923 CONFIG_PHY_GIGE 924 925 If this option is set, support for speed/duplex 926 detection of Gigabit PHY is included. 927 928 CONFIG_PHY_RESET_DELAY 929 930 Some PHY like Intel LXT971A need extra delay after 931 reset before any MII register access is possible. 932 For such PHY, set this option to the usec delay 933 required. (minimum 300usec for LXT971A) 934 935 CONFIG_PHY_CMD_DELAY (ppc4xx) 936 937 Some PHY like Intel LXT971A need extra delay after 938 command issued before MII status register can be read 939 940- Ethernet address: 941 CONFIG_ETHADDR 942 CONFIG_ETH2ADDR 943 CONFIG_ETH3ADDR 944 945 Define a default value for ethernet address to use 946 for the respective ethernet interface, in case this 947 is not determined automatically. 948 949- IP address: 950 CONFIG_IPADDR 951 952 Define a default value for the IP address to use for 953 the default ethernet interface, in case this is not 954 determined through e.g. bootp. 955 956- Server IP address: 957 CONFIG_SERVERIP 958 959 Defines a default value for theIP address of a TFTP 960 server to contact when using the "tftboot" command. 961 962- BOOTP Recovery Mode: 963 CONFIG_BOOTP_RANDOM_DELAY 964 965 If you have many targets in a network that try to 966 boot using BOOTP, you may want to avoid that all 967 systems send out BOOTP requests at precisely the same 968 moment (which would happen for instance at recovery 969 from a power failure, when all systems will try to 970 boot, thus flooding the BOOTP server. Defining 971 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 972 inserted before sending out BOOTP requests. The 973 following delays are insterted then: 974 975 1st BOOTP request: delay 0 ... 1 sec 976 2nd BOOTP request: delay 0 ... 2 sec 977 3rd BOOTP request: delay 0 ... 4 sec 978 4th and following 979 BOOTP requests: delay 0 ... 8 sec 980 981- DHCP Advanced Options: 982 CONFIG_BOOTP_MASK 983 984 You can fine tune the DHCP functionality by adding 985 these flags to the CONFIG_BOOTP_MASK define: 986 987 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 988 serverip from a DHCP server, it is possible that more 989 than one DNS serverip is offered to the client. 990 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 991 serverip will be stored in the additional environment 992 variable "dnsip2". The first DNS serverip is always 993 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 994 is added to the CONFIG_BOOTP_MASK. 995 996 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 997 to do a dynamic update of a DNS server. To do this, they 998 need the hostname of the DHCP requester. 999 If CONFIG_BOOP_SEND_HOSTNAME is added to the 1000 CONFIG_BOOTP_MASK, the content of the "hostname" 1001 environment variable is passed as option 12 to 1002 the DHCP server. 1003 1004 - CDP Options: 1005 CONFIG_CDP_DEVICE_ID 1006 1007 The device id used in CDP trigger frames. 1008 1009 CONFIG_CDP_DEVICE_ID_PREFIX 1010 1011 A two character string which is prefixed to the MAC address 1012 of the device. 1013 1014 CONFIG_CDP_PORT_ID 1015 1016 A printf format string which contains the ascii name of 1017 the port. Normally is set to "eth%d" which sets 1018 eth0 for the first ethernet, eth1 for the second etc. 1019 1020 CONFIG_CDP_CAPABILITIES 1021 1022 A 32bit integer which indicates the device capabilities; 1023 0x00000010 for a normal host which does not forwards. 1024 1025 CONFIG_CDP_VERSION 1026 1027 An ascii string containing the version of the software. 1028 1029 CONFIG_CDP_PLATFORM 1030 1031 An ascii string containing the name of the platform. 1032 1033 CONFIG_CDP_TRIGGER 1034 1035 A 32bit integer sent on the trigger. 1036 1037 CONFIG_CDP_POWER_CONSUMPTION 1038 1039 A 16bit integer containing the power consumption of the 1040 device in .1 of milliwatts. 1041 1042 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1043 1044 A byte containing the id of the VLAN. 1045 1046- Status LED: CONFIG_STATUS_LED 1047 1048 Several configurations allow to display the current 1049 status using a LED. For instance, the LED will blink 1050 fast while running U-Boot code, stop blinking as 1051 soon as a reply to a BOOTP request was received, and 1052 start blinking slow once the Linux kernel is running 1053 (supported by a status LED driver in the Linux 1054 kernel). Defining CONFIG_STATUS_LED enables this 1055 feature in U-Boot. 1056 1057- CAN Support: CONFIG_CAN_DRIVER 1058 1059 Defining CONFIG_CAN_DRIVER enables CAN driver support 1060 on those systems that support this (optional) 1061 feature, like the TQM8xxL modules. 1062 1063- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1064 1065 These enable I2C serial bus commands. Defining either of 1066 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1067 include the appropriate I2C driver for the selected cpu. 1068 1069 This will allow you to use i2c commands at the u-boot 1070 command line (as long as you set CFG_CMD_I2C in 1071 CONFIG_COMMANDS) and communicate with i2c based realtime 1072 clock chips. See common/cmd_i2c.c for a description of the 1073 command line interface. 1074 1075 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 1076 1077 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1078 bit-banging) driver instead of CPM or similar hardware 1079 support for I2C. 1080 1081 There are several other quantities that must also be 1082 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1083 1084 In both cases you will need to define CFG_I2C_SPEED 1085 to be the frequency (in Hz) at which you wish your i2c bus 1086 to run and CFG_I2C_SLAVE to be the address of this node (ie 1087 the cpu's i2c node address). 1088 1089 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1090 sets the cpu up as a master node and so its address should 1091 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1092 p.16-473). So, set CFG_I2C_SLAVE to 0. 1093 1094 That's all that's required for CONFIG_HARD_I2C. 1095 1096 If you use the software i2c interface (CONFIG_SOFT_I2C) 1097 then the following macros need to be defined (examples are 1098 from include/configs/lwmon.h): 1099 1100 I2C_INIT 1101 1102 (Optional). Any commands necessary to enable the I2C 1103 controller or configure ports. 1104 1105 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1106 1107 I2C_PORT 1108 1109 (Only for MPC8260 CPU). The I/O port to use (the code 1110 assumes both bits are on the same port). Valid values 1111 are 0..3 for ports A..D. 1112 1113 I2C_ACTIVE 1114 1115 The code necessary to make the I2C data line active 1116 (driven). If the data line is open collector, this 1117 define can be null. 1118 1119 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1120 1121 I2C_TRISTATE 1122 1123 The code necessary to make the I2C data line tri-stated 1124 (inactive). If the data line is open collector, this 1125 define can be null. 1126 1127 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1128 1129 I2C_READ 1130 1131 Code that returns TRUE if the I2C data line is high, 1132 FALSE if it is low. 1133 1134 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1135 1136 I2C_SDA(bit) 1137 1138 If <bit> is TRUE, sets the I2C data line high. If it 1139 is FALSE, it clears it (low). 1140 1141 eg: #define I2C_SDA(bit) \ 1142 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1143 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1144 1145 I2C_SCL(bit) 1146 1147 If <bit> is TRUE, sets the I2C clock line high. If it 1148 is FALSE, it clears it (low). 1149 1150 eg: #define I2C_SCL(bit) \ 1151 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1152 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1153 1154 I2C_DELAY 1155 1156 This delay is invoked four times per clock cycle so this 1157 controls the rate of data transfer. The data rate thus 1158 is 1 / (I2C_DELAY * 4). Often defined to be something 1159 like: 1160 1161 #define I2C_DELAY udelay(2) 1162 1163 CFG_I2C_INIT_BOARD 1164 1165 When a board is reset during an i2c bus transfer 1166 chips might think that the current transfer is still 1167 in progress. On some boards it is possible to access 1168 the i2c SCLK line directly, either by using the 1169 processor pin as a GPIO or by having a second pin 1170 connected to the bus. If this option is defined a 1171 custom i2c_init_board() routine in boards/xxx/board.c 1172 is run early in the boot sequence. 1173 1174 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1175 1176 This option enables configuration of bi_iic_fast[] flags 1177 in u-boot bd_info structure based on u-boot environment 1178 variable "i2cfast". (see also i2cfast) 1179 1180- SPI Support: CONFIG_SPI 1181 1182 Enables SPI driver (so far only tested with 1183 SPI EEPROM, also an instance works with Crystal A/D and 1184 D/As on the SACSng board) 1185 1186 CONFIG_SPI_X 1187 1188 Enables extended (16-bit) SPI EEPROM addressing. 1189 (symmetrical to CONFIG_I2C_X) 1190 1191 CONFIG_SOFT_SPI 1192 1193 Enables a software (bit-bang) SPI driver rather than 1194 using hardware support. This is a general purpose 1195 driver that only requires three general I/O port pins 1196 (two outputs, one input) to function. If this is 1197 defined, the board configuration must define several 1198 SPI configuration items (port pins to use, etc). For 1199 an example, see include/configs/sacsng.h. 1200 1201- FPGA Support: CONFIG_FPGA_COUNT 1202 1203 Specify the number of FPGA devices to support. 1204 1205 CONFIG_FPGA 1206 1207 Used to specify the types of FPGA devices. For example, 1208 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1209 1210 CFG_FPGA_PROG_FEEDBACK 1211 1212 Enable printing of hash marks during FPGA configuration. 1213 1214 CFG_FPGA_CHECK_BUSY 1215 1216 Enable checks on FPGA configuration interface busy 1217 status by the configuration function. This option 1218 will require a board or device specific function to 1219 be written. 1220 1221 CONFIG_FPGA_DELAY 1222 1223 If defined, a function that provides delays in the FPGA 1224 configuration driver. 1225 1226 CFG_FPGA_CHECK_CTRLC 1227 Allow Control-C to interrupt FPGA configuration 1228 1229 CFG_FPGA_CHECK_ERROR 1230 1231 Check for configuration errors during FPGA bitfile 1232 loading. For example, abort during Virtex II 1233 configuration if the INIT_B line goes low (which 1234 indicated a CRC error). 1235 1236 CFG_FPGA_WAIT_INIT 1237 1238 Maximum time to wait for the INIT_B line to deassert 1239 after PROB_B has been deasserted during a Virtex II 1240 FPGA configuration sequence. The default time is 500 1241 mS. 1242 1243 CFG_FPGA_WAIT_BUSY 1244 1245 Maximum time to wait for BUSY to deassert during 1246 Virtex II FPGA configuration. The default is 5 mS. 1247 1248 CFG_FPGA_WAIT_CONFIG 1249 1250 Time to wait after FPGA configuration. The default is 1251 200 mS. 1252 1253- Configuration Management: 1254 CONFIG_IDENT_STRING 1255 1256 If defined, this string will be added to the U-Boot 1257 version information (U_BOOT_VERSION) 1258 1259- Vendor Parameter Protection: 1260 1261 U-Boot considers the values of the environment 1262 variables "serial#" (Board Serial Number) and 1263 "ethaddr" (Ethernet Address) to be parameters that 1264 are set once by the board vendor / manufacturer, and 1265 protects these variables from casual modification by 1266 the user. Once set, these variables are read-only, 1267 and write or delete attempts are rejected. You can 1268 change this behviour: 1269 1270 If CONFIG_ENV_OVERWRITE is #defined in your config 1271 file, the write protection for vendor parameters is 1272 completely disabled. Anybody can change or delete 1273 these parameters. 1274 1275 Alternatively, if you #define _both_ CONFIG_ETHADDR 1276 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1277 ethernet address is installed in the environment, 1278 which can be changed exactly ONCE by the user. [The 1279 serial# is unaffected by this, i. e. it remains 1280 read-only.] 1281 1282- Protected RAM: 1283 CONFIG_PRAM 1284 1285 Define this variable to enable the reservation of 1286 "protected RAM", i. e. RAM which is not overwritten 1287 by U-Boot. Define CONFIG_PRAM to hold the number of 1288 kB you want to reserve for pRAM. You can overwrite 1289 this default value by defining an environment 1290 variable "pram" to the number of kB you want to 1291 reserve. Note that the board info structure will 1292 still show the full amount of RAM. If pRAM is 1293 reserved, a new environment variable "mem" will 1294 automatically be defined to hold the amount of 1295 remaining RAM in a form that can be passed as boot 1296 argument to Linux, for instance like that: 1297 1298 setenv bootargs ... mem=\$(mem) 1299 saveenv 1300 1301 This way you can tell Linux not to use this memory, 1302 either, which results in a memory region that will 1303 not be affected by reboots. 1304 1305 *WARNING* If your board configuration uses automatic 1306 detection of the RAM size, you must make sure that 1307 this memory test is non-destructive. So far, the 1308 following board configurations are known to be 1309 "pRAM-clean": 1310 1311 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1312 HERMES, IP860, RPXlite, LWMON, LANTEC, 1313 PCU_E, FLAGADM, TQM8260 1314 1315- Error Recovery: 1316 CONFIG_PANIC_HANG 1317 1318 Define this variable to stop the system in case of a 1319 fatal error, so that you have to reset it manually. 1320 This is probably NOT a good idea for an embedded 1321 system where you want to system to reboot 1322 automatically as fast as possible, but it may be 1323 useful during development since you can try to debug 1324 the conditions that lead to the situation. 1325 1326 CONFIG_NET_RETRY_COUNT 1327 1328 This variable defines the number of retries for 1329 network operations like ARP, RARP, TFTP, or BOOTP 1330 before giving up the operation. If not defined, a 1331 default value of 5 is used. 1332 1333- Command Interpreter: 1334 CFG_AUTO_COMPLETE 1335 1336 Enable auto completion of commands using TAB. 1337 1338 CFG_HUSH_PARSER 1339 1340 Define this variable to enable the "hush" shell (from 1341 Busybox) as command line interpreter, thus enabling 1342 powerful command line syntax like 1343 if...then...else...fi conditionals or `&&' and '||' 1344 constructs ("shell scripts"). 1345 1346 If undefined, you get the old, much simpler behaviour 1347 with a somewhat smaller memory footprint. 1348 1349 1350 CFG_PROMPT_HUSH_PS2 1351 1352 This defines the secondary prompt string, which is 1353 printed when the command interpreter needs more input 1354 to complete a command. Usually "> ". 1355 1356 Note: 1357 1358 In the current implementation, the local variables 1359 space and global environment variables space are 1360 separated. Local variables are those you define by 1361 simply typing `name=value'. To access a local 1362 variable later on, you have write `$name' or 1363 `${name}'; to execute the contents of a variable 1364 directly type `$name' at the command prompt. 1365 1366 Global environment variables are those you use 1367 setenv/printenv to work with. To run a command stored 1368 in such a variable, you need to use the run command, 1369 and you must not use the '$' sign to access them. 1370 1371 To store commands and special characters in a 1372 variable, please use double quotation marks 1373 surrounding the whole text of the variable, instead 1374 of the backslashes before semicolons and special 1375 symbols. 1376 1377- Default Environment: 1378 CONFIG_EXTRA_ENV_SETTINGS 1379 1380 Define this to contain any number of null terminated 1381 strings (variable = value pairs) that will be part of 1382 the default environment compiled into the boot image. 1383 1384 For example, place something like this in your 1385 board's config file: 1386 1387 #define CONFIG_EXTRA_ENV_SETTINGS \ 1388 "myvar1=value1\0" \ 1389 "myvar2=value2\0" 1390 1391 Warning: This method is based on knowledge about the 1392 internal format how the environment is stored by the 1393 U-Boot code. This is NOT an official, exported 1394 interface! Although it is unlikely that this format 1395 will change soon, there is no guarantee either. 1396 You better know what you are doing here. 1397 1398 Note: overly (ab)use of the default environment is 1399 discouraged. Make sure to check other ways to preset 1400 the environment like the autoscript function or the 1401 boot command first. 1402 1403- DataFlash Support: 1404 CONFIG_HAS_DATAFLASH 1405 1406 Defining this option enables DataFlash features and 1407 allows to read/write in Dataflash via the standard 1408 commands cp, md... 1409 1410- SystemACE Support: 1411 CONFIG_SYSTEMACE 1412 1413 Adding this option adds support for Xilinx SystemACE 1414 chips attached via some sort of local bus. The address 1415 of the chip must alsh be defined in the 1416 CFG_SYSTEMACE_BASE macro. For example: 1417 1418 #define CONFIG_SYSTEMACE 1419 #define CFG_SYSTEMACE_BASE 0xf0000000 1420 1421 When SystemACE support is added, the "ace" device type 1422 becomes available to the fat commands, i.e. fatls. 1423 1424- Show boot progress: 1425 CONFIG_SHOW_BOOT_PROGRESS 1426 1427 Defining this option allows to add some board- 1428 specific code (calling a user-provided function 1429 "show_boot_progress(int)") that enables you to show 1430 the system's boot progress on some display (for 1431 example, some LED's) on your board. At the moment, 1432 the following checkpoints are implemented: 1433 1434 Arg Where When 1435 1 common/cmd_bootm.c before attempting to boot an image 1436 -1 common/cmd_bootm.c Image header has bad magic number 1437 2 common/cmd_bootm.c Image header has correct magic number 1438 -2 common/cmd_bootm.c Image header has bad checksum 1439 3 common/cmd_bootm.c Image header has correct checksum 1440 -3 common/cmd_bootm.c Image data has bad checksum 1441 4 common/cmd_bootm.c Image data has correct checksum 1442 -4 common/cmd_bootm.c Image is for unsupported architecture 1443 5 common/cmd_bootm.c Architecture check OK 1444 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1445 6 common/cmd_bootm.c Image Type check OK 1446 -6 common/cmd_bootm.c gunzip uncompression error 1447 -7 common/cmd_bootm.c Unimplemented compression type 1448 7 common/cmd_bootm.c Uncompression OK 1449 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1450 8 common/cmd_bootm.c Image Type check OK 1451 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1452 9 common/cmd_bootm.c Start initial ramdisk verification 1453 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1454 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1455 10 common/cmd_bootm.c Ramdisk header is OK 1456 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1457 11 common/cmd_bootm.c Ramdisk data has correct checksum 1458 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1459 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1460 13 common/cmd_bootm.c Start multifile image verification 1461 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1462 15 common/cmd_bootm.c All preparation done, transferring control to OS 1463 1464 -30 lib_ppc/board.c Fatal error, hang the system 1465 -31 post/post.c POST test failed, detected by post_output_backlog() 1466 -32 post/post.c POST test failed, detected by post_run_single() 1467 1468 -1 common/cmd_doc.c Bad usage of "doc" command 1469 -1 common/cmd_doc.c No boot device 1470 -1 common/cmd_doc.c Unknown Chip ID on boot device 1471 -1 common/cmd_doc.c Read Error on boot device 1472 -1 common/cmd_doc.c Image header has bad magic number 1473 1474 -1 common/cmd_ide.c Bad usage of "ide" command 1475 -1 common/cmd_ide.c No boot device 1476 -1 common/cmd_ide.c Unknown boot device 1477 -1 common/cmd_ide.c Unknown partition table 1478 -1 common/cmd_ide.c Invalid partition type 1479 -1 common/cmd_ide.c Read Error on boot device 1480 -1 common/cmd_ide.c Image header has bad magic number 1481 1482 -1 common/cmd_nand.c Bad usage of "nand" command 1483 -1 common/cmd_nand.c No boot device 1484 -1 common/cmd_nand.c Unknown Chip ID on boot device 1485 -1 common/cmd_nand.c Read Error on boot device 1486 -1 common/cmd_nand.c Image header has bad magic number 1487 1488 -1 common/env_common.c Environment has a bad CRC, using default 1489 1490 1491Modem Support: 1492-------------- 1493 1494[so far only for SMDK2400 and TRAB boards] 1495 1496- Modem support endable: 1497 CONFIG_MODEM_SUPPORT 1498 1499- RTS/CTS Flow control enable: 1500 CONFIG_HWFLOW 1501 1502- Modem debug support: 1503 CONFIG_MODEM_SUPPORT_DEBUG 1504 1505 Enables debugging stuff (char screen[1024], dbg()) 1506 for modem support. Useful only with BDI2000. 1507 1508- Interrupt support (PPC): 1509 1510 There are common interrupt_init() and timer_interrupt() 1511 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1512 for cpu specific initialization. interrupt_init_cpu() 1513 should set decrementer_count to appropriate value. If 1514 cpu resets decrementer automatically after interrupt 1515 (ppc4xx) it should set decrementer_count to zero. 1516 timer_interrupt() calls timer_interrupt_cpu() for cpu 1517 specific handling. If board has watchdog / status_led 1518 / other_activity_monitor it works automatically from 1519 general timer_interrupt(). 1520 1521- General: 1522 1523 In the target system modem support is enabled when a 1524 specific key (key combination) is pressed during 1525 power-on. Otherwise U-Boot will boot normally 1526 (autoboot). The key_pressed() fuction is called from 1527 board_init(). Currently key_pressed() is a dummy 1528 function, returning 1 and thus enabling modem 1529 initialization. 1530 1531 If there are no modem init strings in the 1532 environment, U-Boot proceed to autoboot; the 1533 previous output (banner, info printfs) will be 1534 supressed, though. 1535 1536 See also: doc/README.Modem 1537 1538 1539Configuration Settings: 1540----------------------- 1541 1542- CFG_LONGHELP: Defined when you want long help messages included; 1543 undefine this when you're short of memory. 1544 1545- CFG_PROMPT: This is what U-Boot prints on the console to 1546 prompt for user input. 1547 1548- CFG_CBSIZE: Buffer size for input from the Console 1549 1550- CFG_PBSIZE: Buffer size for Console output 1551 1552- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1553 1554- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1555 the application (usually a Linux kernel) when it is 1556 booted 1557 1558- CFG_BAUDRATE_TABLE: 1559 List of legal baudrate settings for this board. 1560 1561- CFG_CONSOLE_INFO_QUIET 1562 Suppress display of console information at boot. 1563 1564- CFG_CONSOLE_IS_IN_ENV 1565 If the board specific function 1566 extern int overwrite_console (void); 1567 returns 1, the stdin, stderr and stdout are switched to the 1568 serial port, else the settings in the environment are used. 1569 1570- CFG_CONSOLE_OVERWRITE_ROUTINE 1571 Enable the call to overwrite_console(). 1572 1573- CFG_CONSOLE_ENV_OVERWRITE 1574 Enable overwrite of previous console environment settings. 1575 1576- CFG_MEMTEST_START, CFG_MEMTEST_END: 1577 Begin and End addresses of the area used by the 1578 simple memory test. 1579 1580- CFG_ALT_MEMTEST: 1581 Enable an alternate, more extensive memory test. 1582 1583- CFG_MEMTEST_SCRATCH: 1584 Scratch address used by the alternate memory test 1585 You only need to set this if address zero isn't writeable 1586 1587- CFG_TFTP_LOADADDR: 1588 Default load address for network file downloads 1589 1590- CFG_LOADS_BAUD_CHANGE: 1591 Enable temporary baudrate change while serial download 1592 1593- CFG_SDRAM_BASE: 1594 Physical start address of SDRAM. _Must_ be 0 here. 1595 1596- CFG_MBIO_BASE: 1597 Physical start address of Motherboard I/O (if using a 1598 Cogent motherboard) 1599 1600- CFG_FLASH_BASE: 1601 Physical start address of Flash memory. 1602 1603- CFG_MONITOR_BASE: 1604 Physical start address of boot monitor code (set by 1605 make config files to be same as the text base address 1606 (TEXT_BASE) used when linking) - same as 1607 CFG_FLASH_BASE when booting from flash. 1608 1609- CFG_MONITOR_LEN: 1610 Size of memory reserved for monitor code, used to 1611 determine _at_compile_time_ (!) if the environment is 1612 embedded within the U-Boot image, or in a separate 1613 flash sector. 1614 1615- CFG_MALLOC_LEN: 1616 Size of DRAM reserved for malloc() use. 1617 1618- CFG_BOOTMAPSZ: 1619 Maximum size of memory mapped by the startup code of 1620 the Linux kernel; all data that must be processed by 1621 the Linux kernel (bd_info, boot arguments, eventually 1622 initrd image) must be put below this limit. 1623 1624- CFG_MAX_FLASH_BANKS: 1625 Max number of Flash memory banks 1626 1627- CFG_MAX_FLASH_SECT: 1628 Max number of sectors on a Flash chip 1629 1630- CFG_FLASH_ERASE_TOUT: 1631 Timeout for Flash erase operations (in ms) 1632 1633- CFG_FLASH_WRITE_TOUT: 1634 Timeout for Flash write operations (in ms) 1635 1636- CFG_FLASH_LOCK_TOUT 1637 Timeout for Flash set sector lock bit operation (in ms) 1638 1639- CFG_FLASH_UNLOCK_TOUT 1640 Timeout for Flash clear lock bits operation (in ms) 1641 1642- CFG_FLASH_PROTECTION 1643 If defined, hardware flash sectors protection is used 1644 instead of U-Boot software protection. 1645 1646- CFG_DIRECT_FLASH_TFTP: 1647 1648 Enable TFTP transfers directly to flash memory; 1649 without this option such a download has to be 1650 performed in two steps: (1) download to RAM, and (2) 1651 copy from RAM to flash. 1652 1653 The two-step approach is usually more reliable, since 1654 you can check if the download worked before you erase 1655 the flash, but in some situations (when sytem RAM is 1656 too limited to allow for a tempory copy of the 1657 downloaded image) this option may be very useful. 1658 1659- CFG_FLASH_CFI: 1660 Define if the flash driver uses extra elements in the 1661 common flash structure for storing flash geometry. 1662 1663- CFG_FLASH_CFI_DRIVER 1664 This option also enables the building of the cfi_flash driver 1665 in the drivers directory 1666 1667- CFG_RX_ETH_BUFFER: 1668 Defines the number of ethernet receive buffers. On some 1669 ethernet controllers it is recommended to set this value 1670 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1671 buffers can be full shortly after enabling the interface 1672 on high ethernet traffic. 1673 Defaults to 4 if not defined. 1674 1675The following definitions that deal with the placement and management 1676of environment data (variable area); in general, we support the 1677following configurations: 1678 1679- CFG_ENV_IS_IN_FLASH: 1680 1681 Define this if the environment is in flash memory. 1682 1683 a) The environment occupies one whole flash sector, which is 1684 "embedded" in the text segment with the U-Boot code. This 1685 happens usually with "bottom boot sector" or "top boot 1686 sector" type flash chips, which have several smaller 1687 sectors at the start or the end. For instance, such a 1688 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1689 such a case you would place the environment in one of the 1690 4 kB sectors - with U-Boot code before and after it. With 1691 "top boot sector" type flash chips, you would put the 1692 environment in one of the last sectors, leaving a gap 1693 between U-Boot and the environment. 1694 1695 - CFG_ENV_OFFSET: 1696 1697 Offset of environment data (variable area) to the 1698 beginning of flash memory; for instance, with bottom boot 1699 type flash chips the second sector can be used: the offset 1700 for this sector is given here. 1701 1702 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1703 1704 - CFG_ENV_ADDR: 1705 1706 This is just another way to specify the start address of 1707 the flash sector containing the environment (instead of 1708 CFG_ENV_OFFSET). 1709 1710 - CFG_ENV_SECT_SIZE: 1711 1712 Size of the sector containing the environment. 1713 1714 1715 b) Sometimes flash chips have few, equal sized, BIG sectors. 1716 In such a case you don't want to spend a whole sector for 1717 the environment. 1718 1719 - CFG_ENV_SIZE: 1720 1721 If you use this in combination with CFG_ENV_IS_IN_FLASH 1722 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1723 of this flash sector for the environment. This saves 1724 memory for the RAM copy of the environment. 1725 1726 It may also save flash memory if you decide to use this 1727 when your environment is "embedded" within U-Boot code, 1728 since then the remainder of the flash sector could be used 1729 for U-Boot code. It should be pointed out that this is 1730 STRONGLY DISCOURAGED from a robustness point of view: 1731 updating the environment in flash makes it always 1732 necessary to erase the WHOLE sector. If something goes 1733 wrong before the contents has been restored from a copy in 1734 RAM, your target system will be dead. 1735 1736 - CFG_ENV_ADDR_REDUND 1737 CFG_ENV_SIZE_REDUND 1738 1739 These settings describe a second storage area used to hold 1740 a redundand copy of the environment data, so that there is 1741 a valid backup copy in case there is a power failure during 1742 a "saveenv" operation. 1743 1744BE CAREFUL! Any changes to the flash layout, and some changes to the 1745source code will make it necessary to adapt <board>/u-boot.lds* 1746accordingly! 1747 1748 1749- CFG_ENV_IS_IN_NVRAM: 1750 1751 Define this if you have some non-volatile memory device 1752 (NVRAM, battery buffered SRAM) which you want to use for the 1753 environment. 1754 1755 - CFG_ENV_ADDR: 1756 - CFG_ENV_SIZE: 1757 1758 These two #defines are used to determin the memory area you 1759 want to use for environment. It is assumed that this memory 1760 can just be read and written to, without any special 1761 provision. 1762 1763BE CAREFUL! The first access to the environment happens quite early 1764in U-Boot initalization (when we try to get the setting of for the 1765console baudrate). You *MUST* have mappend your NVRAM area then, or 1766U-Boot will hang. 1767 1768Please note that even with NVRAM we still use a copy of the 1769environment in RAM: we could work on NVRAM directly, but we want to 1770keep settings there always unmodified except somebody uses "saveenv" 1771to save the current settings. 1772 1773 1774- CFG_ENV_IS_IN_EEPROM: 1775 1776 Use this if you have an EEPROM or similar serial access 1777 device and a driver for it. 1778 1779 - CFG_ENV_OFFSET: 1780 - CFG_ENV_SIZE: 1781 1782 These two #defines specify the offset and size of the 1783 environment area within the total memory of your EEPROM. 1784 1785 - CFG_I2C_EEPROM_ADDR: 1786 If defined, specified the chip address of the EEPROM device. 1787 The default address is zero. 1788 1789 - CFG_EEPROM_PAGE_WRITE_BITS: 1790 If defined, the number of bits used to address bytes in a 1791 single page in the EEPROM device. A 64 byte page, for example 1792 would require six bits. 1793 1794 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1795 If defined, the number of milliseconds to delay between 1796 page writes. The default is zero milliseconds. 1797 1798 - CFG_I2C_EEPROM_ADDR_LEN: 1799 The length in bytes of the EEPROM memory array address. Note 1800 that this is NOT the chip address length! 1801 1802 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 1803 EEPROM chips that implement "address overflow" are ones 1804 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 1805 address and the extra bits end up in the "chip address" bit 1806 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 1807 byte chips. 1808 1809 Note that we consider the length of the address field to 1810 still be one byte because the extra address bits are hidden 1811 in the chip address. 1812 1813 - CFG_EEPROM_SIZE: 1814 The size in bytes of the EEPROM device. 1815 1816 1817- CFG_ENV_IS_IN_DATAFLASH: 1818 1819 Define this if you have a DataFlash memory device which you 1820 want to use for the environment. 1821 1822 - CFG_ENV_OFFSET: 1823 - CFG_ENV_ADDR: 1824 - CFG_ENV_SIZE: 1825 1826 These three #defines specify the offset and size of the 1827 environment area within the total memory of your DataFlash placed 1828 at the specified address. 1829 1830- CFG_ENV_IS_IN_NAND: 1831 1832 Define this if you have a NAND device which you want to use 1833 for the environment. 1834 1835 - CFG_ENV_OFFSET: 1836 - CFG_ENV_SIZE: 1837 1838 These two #defines specify the offset and size of the environment 1839 area within the first NAND device. 1840 1841- CFG_SPI_INIT_OFFSET 1842 1843 Defines offset to the initial SPI buffer area in DPRAM. The 1844 area is used at an early stage (ROM part) if the environment 1845 is configured to reside in the SPI EEPROM: We need a 520 byte 1846 scratch DPRAM area. It is used between the two initialization 1847 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1848 to be a good choice since it makes it far enough from the 1849 start of the data area as well as from the stack pointer. 1850 1851Please note that the environment is read-only as long as the monitor 1852has been relocated to RAM and a RAM copy of the environment has been 1853created; also, when using EEPROM you will have to use getenv_r() 1854until then to read environment variables. 1855 1856The environment is protected by a CRC32 checksum. Before the monitor 1857is relocated into RAM, as a result of a bad CRC you will be working 1858with the compiled-in default environment - *silently*!!! [This is 1859necessary, because the first environment variable we need is the 1860"baudrate" setting for the console - if we have a bad CRC, we don't 1861have any device yet where we could complain.] 1862 1863Note: once the monitor has been relocated, then it will complain if 1864the default environment is used; a new CRC is computed as soon as you 1865use the "saveenv" command to store a valid environment. 1866 1867- CFG_FAULT_ECHO_LINK_DOWN: 1868 Echo the inverted Ethernet link state to the fault LED. 1869 1870 Note: If this option is active, then CFG_FAULT_MII_ADDR 1871 also needs to be defined. 1872 1873- CFG_FAULT_MII_ADDR: 1874 MII address of the PHY to check for the Ethernet link state. 1875 1876- CFG_64BIT_VSPRINTF: 1877 Makes vsprintf (and all *printf functions) support printing 1878 of 64bit values by using the L quantifier 1879 1880- CFG_64BIT_STRTOUL: 1881 Adds simple_strtoull that returns a 64bit value 1882 1883Low Level (hardware related) configuration options: 1884--------------------------------------------------- 1885 1886- CFG_CACHELINE_SIZE: 1887 Cache Line Size of the CPU. 1888 1889- CFG_DEFAULT_IMMR: 1890 Default address of the IMMR after system reset. 1891 1892 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1893 and RPXsuper) to be able to adjust the position of 1894 the IMMR register after a reset. 1895 1896- Floppy Disk Support: 1897 CFG_FDC_DRIVE_NUMBER 1898 1899 the default drive number (default value 0) 1900 1901 CFG_ISA_IO_STRIDE 1902 1903 defines the spacing between fdc chipset registers 1904 (default value 1) 1905 1906 CFG_ISA_IO_OFFSET 1907 1908 defines the offset of register from address. It 1909 depends on which part of the data bus is connected to 1910 the fdc chipset. (default value 0) 1911 1912 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1913 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1914 default value. 1915 1916 if CFG_FDC_HW_INIT is defined, then the function 1917 fdc_hw_init() is called at the beginning of the FDC 1918 setup. fdc_hw_init() must be provided by the board 1919 source code. It is used to make hardware dependant 1920 initializations. 1921 1922- CFG_IMMR: Physical address of the Internal Memory Mapped 1923 Register; DO NOT CHANGE! (11-4) 1924 [MPC8xx systems only] 1925 1926- CFG_INIT_RAM_ADDR: 1927 1928 Start address of memory area that can be used for 1929 initial data and stack; please note that this must be 1930 writable memory that is working WITHOUT special 1931 initialization, i. e. you CANNOT use normal RAM which 1932 will become available only after programming the 1933 memory controller and running certain initialization 1934 sequences. 1935 1936 U-Boot uses the following memory types: 1937 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1938 - MPC824X: data cache 1939 - PPC4xx: data cache 1940 1941- CFG_GBL_DATA_OFFSET: 1942 1943 Offset of the initial data structure in the memory 1944 area defined by CFG_INIT_RAM_ADDR. Usually 1945 CFG_GBL_DATA_OFFSET is chosen such that the initial 1946 data is located at the end of the available space 1947 (sometimes written as (CFG_INIT_RAM_END - 1948 CFG_INIT_DATA_SIZE), and the initial stack is just 1949 below that area (growing from (CFG_INIT_RAM_ADDR + 1950 CFG_GBL_DATA_OFFSET) downward. 1951 1952 Note: 1953 On the MPC824X (or other systems that use the data 1954 cache for initial memory) the address chosen for 1955 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1956 point to an otherwise UNUSED address space between 1957 the top of RAM and the start of the PCI space. 1958 1959- CFG_SIUMCR: SIU Module Configuration (11-6) 1960 1961- CFG_SYPCR: System Protection Control (11-9) 1962 1963- CFG_TBSCR: Time Base Status and Control (11-26) 1964 1965- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1966 1967- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1968 1969- CFG_SCCR: System Clock and reset Control Register (15-27) 1970 1971- CFG_OR_TIMING_SDRAM: 1972 SDRAM timing 1973 1974- CFG_MAMR_PTA: 1975 periodic timer for refresh 1976 1977- CFG_DER: Debug Event Register (37-47) 1978 1979- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1980 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1981 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1982 CFG_BR1_PRELIM: 1983 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1984 1985- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1986 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1987 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1988 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1989 1990- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1991 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1992 Machine Mode Register and Memory Periodic Timer 1993 Prescaler definitions (SDRAM timing) 1994 1995- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1996 enable I2C microcode relocation patch (MPC8xx); 1997 define relocation offset in DPRAM [DSP2] 1998 1999- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 2000 enable SPI microcode relocation patch (MPC8xx); 2001 define relocation offset in DPRAM [SCC4] 2002 2003- CFG_USE_OSCCLK: 2004 Use OSCM clock mode on MBX8xx board. Be careful, 2005 wrong setting might damage your board. Read 2006 doc/README.MBX before setting this variable! 2007 2008- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 2009 Offset of the bootmode word in DPRAM used by post 2010 (Power On Self Tests). This definition overrides 2011 #define'd default value in commproc.h resp. 2012 cpm_8260.h. 2013 2014- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 2015 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 2016 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 2017 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 2018 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 2019 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 2020 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 2021 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 2022 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 2023 2024- CONFIG_ETHER_ON_FEC[12] 2025 Define to enable FEC[12] on a 8xx series processor. 2026 2027- CONFIG_FEC[12]_PHY 2028 Define to the hardcoded PHY address which corresponds 2029 to the given FEC; i. e. 2030 #define CONFIG_FEC1_PHY 4 2031 means that the PHY with address 4 is connected to FEC1 2032 2033 When set to -1, means to probe for first available. 2034 2035- CONFIG_FEC[12]_PHY_NORXERR 2036 The PHY does not have a RXERR line (RMII only). 2037 (so program the FEC to ignore it). 2038 2039- CONFIG_RMII 2040 Enable RMII mode for all FECs. 2041 Note that this is a global option, we can't 2042 have one FEC in standard MII mode and another in RMII mode. 2043 2044- CONFIG_CRC32_VERIFY 2045 Add a verify option to the crc32 command. 2046 The syntax is: 2047 2048 => crc32 -v <address> <count> <crc32> 2049 2050 Where address/count indicate a memory area 2051 and crc32 is the correct crc32 which the 2052 area should have. 2053 2054Building the Software: 2055====================== 2056 2057Building U-Boot has been tested in native PPC environments (on a 2058PowerBook G3 running LinuxPPC 2000) and in cross environments 2059(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2060NetBSD 1.5 on x86). 2061 2062If you are not using a native PPC environment, it is assumed that you 2063have the GNU cross compiling tools available in your path and named 2064with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2065you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2066the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2067change it to: 2068 2069 CROSS_COMPILE = ppc_4xx- 2070 2071 2072U-Boot is intended to be simple to build. After installing the 2073sources you must configure U-Boot for one specific board type. This 2074is done by typing: 2075 2076 make NAME_config 2077 2078where "NAME_config" is the name of one of the existing 2079configurations; the following names are supported: 2080 2081 ADCIOP_config FPS860L_config omap730p2_config 2082 ADS860_config GEN860T_config pcu_e_config 2083 AR405_config GENIETV_config PIP405_config 2084 at91rm9200dk_config GTH_config QS823_config 2085 CANBT_config hermes_config QS850_config 2086 cmi_mpc5xx_config hymod_config QS860T_config 2087 cogent_common_config IP860_config RPXlite_config 2088 cogent_mpc8260_config IVML24_config RPXsuper_config 2089 cogent_mpc8xx_config IVMS8_config rsdproto_config 2090 CPCI405_config JSE_config Sandpoint8240_config 2091 CPCIISER4_config LANTEC_config sbc8260_config 2092 csb272_config lwmon_config SM850_config 2093 CU824_config MBX860T_config SPD823TS_config 2094 DUET_ADS_config MBX_config stxgp3_config 2095 EBONY_config MPC8260ADS_config SXNI855T_config 2096 ELPT860_config MPC8540ADS_config TQM823L_config 2097 ESTEEM192E_config MPC8560ADS_config TQM850L_config 2098 ETX094_config NETVIA_config TQM855L_config 2099 FADS823_config omap1510inn_config TQM860L_config 2100 FADS850SAR_config omap1610h2_config WALNUT405_config 2101 FADS860T_config omap1610inn_config ZPC1900_config 2102 FPS850L_config omap5912osk_config 2103 2104Note: for some board special configuration names may exist; check if 2105 additional information is available from the board vendor; for 2106 instance, the TQM823L systems are available without (standard) 2107 or with LCD support. You can select such additional "features" 2108 when chosing the configuration, i. e. 2109 2110 make TQM823L_config 2111 - will configure for a plain TQM823L, i. e. no LCD support 2112 2113 make TQM823L_LCD_config 2114 - will configure for a TQM823L with U-Boot console on LCD 2115 2116 etc. 2117 2118 2119Finally, type "make all", and you should get some working U-Boot 2120images ready for download to / installation on your system: 2121 2122- "u-boot.bin" is a raw binary image 2123- "u-boot" is an image in ELF binary format 2124- "u-boot.srec" is in Motorola S-Record format 2125 2126 2127Please be aware that the Makefiles assume you are using GNU make, so 2128for instance on NetBSD you might need to use "gmake" instead of 2129native "make". 2130 2131 2132If the system board that you have is not listed, then you will need 2133to port U-Boot to your hardware platform. To do this, follow these 2134steps: 2135 21361. Add a new configuration option for your board to the toplevel 2137 "Makefile" and to the "MAKEALL" script, using the existing 2138 entries as examples. Note that here and at many other places 2139 boards and other names are listed in alphabetical sort order. Please 2140 keep this order. 21412. Create a new directory to hold your board specific code. Add any 2142 files you need. In your board directory, you will need at least 2143 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 21443. Create a new configuration file "include/configs/<board>.h" for 2145 your board 21463. If you're porting U-Boot to a new CPU, then also create a new 2147 directory to hold your CPU specific code. Add any files you need. 21484. Run "make <board>_config" with your new name. 21495. Type "make", and you should get a working "u-boot.srec" file 2150 to be installed on your target system. 21516. Debug and solve any problems that might arise. 2152 [Of course, this last step is much harder than it sounds.] 2153 2154 2155Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2156============================================================== 2157 2158If you have modified U-Boot sources (for instance added a new board 2159or support for new devices, a new CPU, etc.) you are expected to 2160provide feedback to the other developers. The feedback normally takes 2161the form of a "patch", i. e. a context diff against a certain (latest 2162official or latest in CVS) version of U-Boot sources. 2163 2164But before you submit such a patch, please verify that your modifi- 2165cation did not break existing code. At least make sure that *ALL* of 2166the supported boards compile WITHOUT ANY compiler warnings. To do so, 2167just run the "MAKEALL" script, which will configure and build U-Boot 2168for ALL supported system. Be warned, this will take a while. You can 2169select which (cross) compiler to use by passing a `CROSS_COMPILE' 2170environment variable to the script, i. e. to use the cross tools from 2171MontaVista's Hard Hat Linux you can type 2172 2173 CROSS_COMPILE=ppc_8xx- MAKEALL 2174 2175or to build on a native PowerPC system you can type 2176 2177 CROSS_COMPILE=' ' MAKEALL 2178 2179See also "U-Boot Porting Guide" below. 2180 2181 2182Monitor Commands - Overview: 2183============================ 2184 2185go - start application at address 'addr' 2186run - run commands in an environment variable 2187bootm - boot application image from memory 2188bootp - boot image via network using BootP/TFTP protocol 2189tftpboot- boot image via network using TFTP protocol 2190 and env variables "ipaddr" and "serverip" 2191 (and eventually "gatewayip") 2192rarpboot- boot image via network using RARP/TFTP protocol 2193diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2194loads - load S-Record file over serial line 2195loadb - load binary file over serial line (kermit mode) 2196md - memory display 2197mm - memory modify (auto-incrementing) 2198nm - memory modify (constant address) 2199mw - memory write (fill) 2200cp - memory copy 2201cmp - memory compare 2202crc32 - checksum calculation 2203imd - i2c memory display 2204imm - i2c memory modify (auto-incrementing) 2205inm - i2c memory modify (constant address) 2206imw - i2c memory write (fill) 2207icrc32 - i2c checksum calculation 2208iprobe - probe to discover valid I2C chip addresses 2209iloop - infinite loop on address range 2210isdram - print SDRAM configuration information 2211sspi - SPI utility commands 2212base - print or set address offset 2213printenv- print environment variables 2214setenv - set environment variables 2215saveenv - save environment variables to persistent storage 2216protect - enable or disable FLASH write protection 2217erase - erase FLASH memory 2218flinfo - print FLASH memory information 2219bdinfo - print Board Info structure 2220iminfo - print header information for application image 2221coninfo - print console devices and informations 2222ide - IDE sub-system 2223loop - infinite loop on address range 2224mtest - simple RAM test 2225icache - enable or disable instruction cache 2226dcache - enable or disable data cache 2227reset - Perform RESET of the CPU 2228echo - echo args to console 2229version - print monitor version 2230help - print online help 2231? - alias for 'help' 2232 2233 2234Monitor Commands - Detailed Description: 2235======================================== 2236 2237TODO. 2238 2239For now: just type "help <command>". 2240 2241 2242Environment Variables: 2243====================== 2244 2245U-Boot supports user configuration using Environment Variables which 2246can be made persistent by saving to Flash memory. 2247 2248Environment Variables are set using "setenv", printed using 2249"printenv", and saved to Flash using "saveenv". Using "setenv" 2250without a value can be used to delete a variable from the 2251environment. As long as you don't save the environment you are 2252working with an in-memory copy. In case the Flash area containing the 2253environment is erased by accident, a default environment is provided. 2254 2255Some configuration options can be set using Environment Variables: 2256 2257 baudrate - see CONFIG_BAUDRATE 2258 2259 bootdelay - see CONFIG_BOOTDELAY 2260 2261 bootcmd - see CONFIG_BOOTCOMMAND 2262 2263 bootargs - Boot arguments when booting an RTOS image 2264 2265 bootfile - Name of the image to load with TFTP 2266 2267 autoload - if set to "no" (any string beginning with 'n'), 2268 "bootp" will just load perform a lookup of the 2269 configuration from the BOOTP server, but not try to 2270 load any image using TFTP 2271 2272 autostart - if set to "yes", an image loaded using the "bootp", 2273 "rarpboot", "tftpboot" or "diskboot" commands will 2274 be automatically started (by internally calling 2275 "bootm") 2276 2277 If set to "no", a standalone image passed to the 2278 "bootm" command will be copied to the load address 2279 (and eventually uncompressed), but NOT be started. 2280 This can be used to load and uncompress arbitrary 2281 data. 2282 2283 i2cfast - (PPC405GP|PPC405EP only) 2284 if set to 'y' configures Linux I2C driver for fast 2285 mode (400kHZ). This environment variable is used in 2286 initialization code. So, for changes to be effective 2287 it must be saved and board must be reset. 2288 2289 initrd_high - restrict positioning of initrd images: 2290 If this variable is not set, initrd images will be 2291 copied to the highest possible address in RAM; this 2292 is usually what you want since it allows for 2293 maximum initrd size. If for some reason you want to 2294 make sure that the initrd image is loaded below the 2295 CFG_BOOTMAPSZ limit, you can set this environment 2296 variable to a value of "no" or "off" or "0". 2297 Alternatively, you can set it to a maximum upper 2298 address to use (U-Boot will still check that it 2299 does not overwrite the U-Boot stack and data). 2300 2301 For instance, when you have a system with 16 MB 2302 RAM, and want to reserve 4 MB from use by Linux, 2303 you can do this by adding "mem=12M" to the value of 2304 the "bootargs" variable. However, now you must make 2305 sure that the initrd image is placed in the first 2306 12 MB as well - this can be done with 2307 2308 setenv initrd_high 00c00000 2309 2310 If you set initrd_high to 0xFFFFFFFF, this is an 2311 indication to U-Boot that all addresses are legal 2312 for the Linux kernel, including addresses in flash 2313 memory. In this case U-Boot will NOT COPY the 2314 ramdisk at all. This may be useful to reduce the 2315 boot time on your system, but requires that this 2316 feature is supported by your Linux kernel. 2317 2318 ipaddr - IP address; needed for tftpboot command 2319 2320 loadaddr - Default load address for commands like "bootp", 2321 "rarpboot", "tftpboot", "loadb" or "diskboot" 2322 2323 loads_echo - see CONFIG_LOADS_ECHO 2324 2325 serverip - TFTP server IP address; needed for tftpboot command 2326 2327 bootretry - see CONFIG_BOOT_RETRY_TIME 2328 2329 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2330 2331 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2332 2333 ethprime - When CONFIG_NET_MULTI is enabled controls which 2334 interface is used first. 2335 2336 ethact - When CONFIG_NET_MULTI is enabled controls which 2337 interface is currently active. For example you 2338 can do the following 2339 2340 => setenv ethact FEC ETHERNET 2341 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2342 => setenv ethact SCC ETHERNET 2343 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2344 2345 netretry - When set to "no" each network operation will 2346 either succeed or fail without retrying. 2347 When set to "once" the network operation will 2348 fail when all the available network interfaces 2349 are tried once without success. 2350 Useful on scripts which control the retry operation 2351 themselves. 2352 2353 vlan - When set to a value < 4095 the traffic over 2354 ethernet is encapsulated/received over 802.1q 2355 VLAN tagged frames. 2356 2357The following environment variables may be used and automatically 2358updated by the network boot commands ("bootp" and "rarpboot"), 2359depending the information provided by your boot server: 2360 2361 bootfile - see above 2362 dnsip - IP address of your Domain Name Server 2363 dnsip2 - IP address of your secondary Domain Name Server 2364 gatewayip - IP address of the Gateway (Router) to use 2365 hostname - Target hostname 2366 ipaddr - see above 2367 netmask - Subnet Mask 2368 rootpath - Pathname of the root filesystem on the NFS server 2369 serverip - see above 2370 2371 2372There are two special Environment Variables: 2373 2374 serial# - contains hardware identification information such 2375 as type string and/or serial number 2376 ethaddr - Ethernet address 2377 2378These variables can be set only once (usually during manufacturing of 2379the board). U-Boot refuses to delete or overwrite these variables 2380once they have been set once. 2381 2382 2383Further special Environment Variables: 2384 2385 ver - Contains the U-Boot version string as printed 2386 with the "version" command. This variable is 2387 readonly (see CONFIG_VERSION_VARIABLE). 2388 2389 2390Please note that changes to some configuration parameters may take 2391only effect after the next boot (yes, that's just like Windoze :-). 2392 2393 2394Command Line Parsing: 2395===================== 2396 2397There are two different command line parsers available with U-Boot: 2398the old "simple" one, and the much more powerful "hush" shell: 2399 2400Old, simple command line parser: 2401-------------------------------- 2402 2403- supports environment variables (through setenv / saveenv commands) 2404- several commands on one line, separated by ';' 2405- variable substitution using "... $(name) ..." syntax 2406- special characters ('$', ';') can be escaped by prefixing with '\', 2407 for example: 2408 setenv bootcmd bootm \$(address) 2409- You can also escape text by enclosing in single apostrophes, for example: 2410 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2411 2412Hush shell: 2413----------- 2414 2415- similar to Bourne shell, with control structures like 2416 if...then...else...fi, for...do...done; while...do...done, 2417 until...do...done, ... 2418- supports environment ("global") variables (through setenv / saveenv 2419 commands) and local shell variables (through standard shell syntax 2420 "name=value"); only environment variables can be used with "run" 2421 command 2422 2423General rules: 2424-------------- 2425 2426(1) If a command line (or an environment variable executed by a "run" 2427 command) contains several commands separated by semicolon, and 2428 one of these commands fails, then the remaining commands will be 2429 executed anyway. 2430 2431(2) If you execute several variables with one call to run (i. e. 2432 calling run with a list af variables as arguments), any failing 2433 command will cause "run" to terminate, i. e. the remaining 2434 variables are not executed. 2435 2436Note for Redundant Ethernet Interfaces: 2437======================================= 2438 2439Some boards come with redundant ethernet interfaces; U-Boot supports 2440such configurations and is capable of automatic selection of a 2441"working" interface when needed. MAC assignment works as follows: 2442 2443Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2444MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2445"eth1addr" (=>eth1), "eth2addr", ... 2446 2447If the network interface stores some valid MAC address (for instance 2448in SROM), this is used as default address if there is NO correspon- 2449ding setting in the environment; if the corresponding environment 2450variable is set, this overrides the settings in the card; that means: 2451 2452o If the SROM has a valid MAC address, and there is no address in the 2453 environment, the SROM's address is used. 2454 2455o If there is no valid address in the SROM, and a definition in the 2456 environment exists, then the value from the environment variable is 2457 used. 2458 2459o If both the SROM and the environment contain a MAC address, and 2460 both addresses are the same, this MAC address is used. 2461 2462o If both the SROM and the environment contain a MAC address, and the 2463 addresses differ, the value from the environment is used and a 2464 warning is printed. 2465 2466o If neither SROM nor the environment contain a MAC address, an error 2467 is raised. 2468 2469 2470Image Formats: 2471============== 2472 2473The "boot" commands of this monitor operate on "image" files which 2474can be basicly anything, preceeded by a special header; see the 2475definitions in include/image.h for details; basicly, the header 2476defines the following image properties: 2477 2478* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2479 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2480 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2481 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2482* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2483 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2484 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC). 2485* Compression Type (uncompressed, gzip, bzip2) 2486* Load Address 2487* Entry Point 2488* Image Name 2489* Image Timestamp 2490 2491The header is marked by a special Magic Number, and both the header 2492and the data portions of the image are secured against corruption by 2493CRC32 checksums. 2494 2495 2496Linux Support: 2497============== 2498 2499Although U-Boot should support any OS or standalone application 2500easily, the main focus has always been on Linux during the design of 2501U-Boot. 2502 2503U-Boot includes many features that so far have been part of some 2504special "boot loader" code within the Linux kernel. Also, any 2505"initrd" images to be used are no longer part of one big Linux image; 2506instead, kernel and "initrd" are separate images. This implementation 2507serves several purposes: 2508 2509- the same features can be used for other OS or standalone 2510 applications (for instance: using compressed images to reduce the 2511 Flash memory footprint) 2512 2513- it becomes much easier to port new Linux kernel versions because 2514 lots of low-level, hardware dependent stuff are done by U-Boot 2515 2516- the same Linux kernel image can now be used with different "initrd" 2517 images; of course this also means that different kernel images can 2518 be run with the same "initrd". This makes testing easier (you don't 2519 have to build a new "zImage.initrd" Linux image when you just 2520 change a file in your "initrd"). Also, a field-upgrade of the 2521 software is easier now. 2522 2523 2524Linux HOWTO: 2525============ 2526 2527Porting Linux to U-Boot based systems: 2528--------------------------------------- 2529 2530U-Boot cannot save you from doing all the necessary modifications to 2531configure the Linux device drivers for use with your target hardware 2532(no, we don't intend to provide a full virtual machine interface to 2533Linux :-). 2534 2535But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2536 2537Just make sure your machine specific header file (for instance 2538include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2539Information structure as we define in include/u-boot.h, and make 2540sure that your definition of IMAP_ADDR uses the same value as your 2541U-Boot configuration in CFG_IMMR. 2542 2543 2544Configuring the Linux kernel: 2545----------------------------- 2546 2547No specific requirements for U-Boot. Make sure you have some root 2548device (initial ramdisk, NFS) for your target system. 2549 2550 2551Building a Linux Image: 2552----------------------- 2553 2554With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2555not used. If you use recent kernel source, a new build target 2556"uImage" will exist which automatically builds an image usable by 2557U-Boot. Most older kernels also have support for a "pImage" target, 2558which was introduced for our predecessor project PPCBoot and uses a 2559100% compatible format. 2560 2561Example: 2562 2563 make TQM850L_config 2564 make oldconfig 2565 make dep 2566 make uImage 2567 2568The "uImage" build target uses a special tool (in 'tools/mkimage') to 2569encapsulate a compressed Linux kernel image with header information, 2570CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2571 2572* build a standard "vmlinux" kernel image (in ELF binary format): 2573 2574* convert the kernel into a raw binary image: 2575 2576 ${CROSS_COMPILE}-objcopy -O binary \ 2577 -R .note -R .comment \ 2578 -S vmlinux linux.bin 2579 2580* compress the binary image: 2581 2582 gzip -9 linux.bin 2583 2584* package compressed binary image for U-Boot: 2585 2586 mkimage -A ppc -O linux -T kernel -C gzip \ 2587 -a 0 -e 0 -n "Linux Kernel Image" \ 2588 -d linux.bin.gz uImage 2589 2590 2591The "mkimage" tool can also be used to create ramdisk images for use 2592with U-Boot, either separated from the Linux kernel image, or 2593combined into one file. "mkimage" encapsulates the images with a 64 2594byte header containing information about target architecture, 2595operating system, image type, compression method, entry points, time 2596stamp, CRC32 checksums, etc. 2597 2598"mkimage" can be called in two ways: to verify existing images and 2599print the header information, or to build new images. 2600 2601In the first form (with "-l" option) mkimage lists the information 2602contained in the header of an existing U-Boot image; this includes 2603checksum verification: 2604 2605 tools/mkimage -l image 2606 -l ==> list image header information 2607 2608The second form (with "-d" option) is used to build a U-Boot image 2609from a "data file" which is used as image payload: 2610 2611 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2612 -n name -d data_file image 2613 -A ==> set architecture to 'arch' 2614 -O ==> set operating system to 'os' 2615 -T ==> set image type to 'type' 2616 -C ==> set compression type 'comp' 2617 -a ==> set load address to 'addr' (hex) 2618 -e ==> set entry point to 'ep' (hex) 2619 -n ==> set image name to 'name' 2620 -d ==> use image data from 'datafile' 2621 2622Right now, all Linux kernels for PowerPC systems use the same load 2623address (0x00000000), but the entry point address depends on the 2624kernel version: 2625 2626- 2.2.x kernels have the entry point at 0x0000000C, 2627- 2.3.x and later kernels have the entry point at 0x00000000. 2628 2629So a typical call to build a U-Boot image would read: 2630 2631 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2632 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2633 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2634 > examples/uImage.TQM850L 2635 Image Name: 2.4.4 kernel for TQM850L 2636 Created: Wed Jul 19 02:34:59 2000 2637 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2638 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2639 Load Address: 0x00000000 2640 Entry Point: 0x00000000 2641 2642To verify the contents of the image (or check for corruption): 2643 2644 -> tools/mkimage -l examples/uImage.TQM850L 2645 Image Name: 2.4.4 kernel for TQM850L 2646 Created: Wed Jul 19 02:34:59 2000 2647 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2648 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2649 Load Address: 0x00000000 2650 Entry Point: 0x00000000 2651 2652NOTE: for embedded systems where boot time is critical you can trade 2653speed for memory and install an UNCOMPRESSED image instead: this 2654needs more space in Flash, but boots much faster since it does not 2655need to be uncompressed: 2656 2657 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2658 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2659 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2660 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2661 > examples/uImage.TQM850L-uncompressed 2662 Image Name: 2.4.4 kernel for TQM850L 2663 Created: Wed Jul 19 02:34:59 2000 2664 Image Type: PowerPC Linux Kernel Image (uncompressed) 2665 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2666 Load Address: 0x00000000 2667 Entry Point: 0x00000000 2668 2669 2670Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2671when your kernel is intended to use an initial ramdisk: 2672 2673 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2674 > -A ppc -O linux -T ramdisk -C gzip \ 2675 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2676 Image Name: Simple Ramdisk Image 2677 Created: Wed Jan 12 14:01:50 2000 2678 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2679 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2680 Load Address: 0x00000000 2681 Entry Point: 0x00000000 2682 2683 2684Installing a Linux Image: 2685------------------------- 2686 2687To downloading a U-Boot image over the serial (console) interface, 2688you must convert the image to S-Record format: 2689 2690 objcopy -I binary -O srec examples/image examples/image.srec 2691 2692The 'objcopy' does not understand the information in the U-Boot 2693image header, so the resulting S-Record file will be relative to 2694address 0x00000000. To load it to a given address, you need to 2695specify the target address as 'offset' parameter with the 'loads' 2696command. 2697 2698Example: install the image to address 0x40100000 (which on the 2699TQM8xxL is in the first Flash bank): 2700 2701 => erase 40100000 401FFFFF 2702 2703 .......... done 2704 Erased 8 sectors 2705 2706 => loads 40100000 2707 ## Ready for S-Record download ... 2708 ~>examples/image.srec 2709 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2710 ... 2711 15989 15990 15991 15992 2712 [file transfer complete] 2713 [connected] 2714 ## Start Addr = 0x00000000 2715 2716 2717You can check the success of the download using the 'iminfo' command; 2718this includes a checksum verification so you can be sure no data 2719corruption happened: 2720 2721 => imi 40100000 2722 2723 ## Checking Image at 40100000 ... 2724 Image Name: 2.2.13 for initrd on TQM850L 2725 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2726 Data Size: 335725 Bytes = 327 kB = 0 MB 2727 Load Address: 00000000 2728 Entry Point: 0000000c 2729 Verifying Checksum ... OK 2730 2731 2732Boot Linux: 2733----------- 2734 2735The "bootm" command is used to boot an application that is stored in 2736memory (RAM or Flash). In case of a Linux kernel image, the contents 2737of the "bootargs" environment variable is passed to the kernel as 2738parameters. You can check and modify this variable using the 2739"printenv" and "setenv" commands: 2740 2741 2742 => printenv bootargs 2743 bootargs=root=/dev/ram 2744 2745 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2746 2747 => printenv bootargs 2748 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2749 2750 => bootm 40020000 2751 ## Booting Linux kernel at 40020000 ... 2752 Image Name: 2.2.13 for NFS on TQM850L 2753 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2754 Data Size: 381681 Bytes = 372 kB = 0 MB 2755 Load Address: 00000000 2756 Entry Point: 0000000c 2757 Verifying Checksum ... OK 2758 Uncompressing Kernel Image ... OK 2759 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 2760 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2761 time_init: decrementer frequency = 187500000/60 2762 Calibrating delay loop... 49.77 BogoMIPS 2763 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2764 ... 2765 2766If you want to boot a Linux kernel with initial ram disk, you pass 2767the memory addresses of both the kernel and the initrd image (PPBCOOT 2768format!) to the "bootm" command: 2769 2770 => imi 40100000 40200000 2771 2772 ## Checking Image at 40100000 ... 2773 Image Name: 2.2.13 for initrd on TQM850L 2774 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2775 Data Size: 335725 Bytes = 327 kB = 0 MB 2776 Load Address: 00000000 2777 Entry Point: 0000000c 2778 Verifying Checksum ... OK 2779 2780 ## Checking Image at 40200000 ... 2781 Image Name: Simple Ramdisk Image 2782 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2783 Data Size: 566530 Bytes = 553 kB = 0 MB 2784 Load Address: 00000000 2785 Entry Point: 00000000 2786 Verifying Checksum ... OK 2787 2788 => bootm 40100000 40200000 2789 ## Booting Linux kernel at 40100000 ... 2790 Image Name: 2.2.13 for initrd on TQM850L 2791 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2792 Data Size: 335725 Bytes = 327 kB = 0 MB 2793 Load Address: 00000000 2794 Entry Point: 0000000c 2795 Verifying Checksum ... OK 2796 Uncompressing Kernel Image ... OK 2797 ## Loading RAMDisk Image at 40200000 ... 2798 Image Name: Simple Ramdisk Image 2799 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2800 Data Size: 566530 Bytes = 553 kB = 0 MB 2801 Load Address: 00000000 2802 Entry Point: 00000000 2803 Verifying Checksum ... OK 2804 Loading Ramdisk ... OK 2805 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 2806 Boot arguments: root=/dev/ram 2807 time_init: decrementer frequency = 187500000/60 2808 Calibrating delay loop... 49.77 BogoMIPS 2809 ... 2810 RAMDISK: Compressed image found at block 0 2811 VFS: Mounted root (ext2 filesystem). 2812 2813 bash# 2814 2815More About U-Boot Image Types: 2816------------------------------ 2817 2818U-Boot supports the following image types: 2819 2820 "Standalone Programs" are directly runnable in the environment 2821 provided by U-Boot; it is expected that (if they behave 2822 well) you can continue to work in U-Boot after return from 2823 the Standalone Program. 2824 "OS Kernel Images" are usually images of some Embedded OS which 2825 will take over control completely. Usually these programs 2826 will install their own set of exception handlers, device 2827 drivers, set up the MMU, etc. - this means, that you cannot 2828 expect to re-enter U-Boot except by resetting the CPU. 2829 "RAMDisk Images" are more or less just data blocks, and their 2830 parameters (address, size) are passed to an OS kernel that is 2831 being started. 2832 "Multi-File Images" contain several images, typically an OS 2833 (Linux) kernel image and one or more data images like 2834 RAMDisks. This construct is useful for instance when you want 2835 to boot over the network using BOOTP etc., where the boot 2836 server provides just a single image file, but you want to get 2837 for instance an OS kernel and a RAMDisk image. 2838 2839 "Multi-File Images" start with a list of image sizes, each 2840 image size (in bytes) specified by an "uint32_t" in network 2841 byte order. This list is terminated by an "(uint32_t)0". 2842 Immediately after the terminating 0 follow the images, one by 2843 one, all aligned on "uint32_t" boundaries (size rounded up to 2844 a multiple of 4 bytes). 2845 2846 "Firmware Images" are binary images containing firmware (like 2847 U-Boot or FPGA images) which usually will be programmed to 2848 flash memory. 2849 2850 "Script files" are command sequences that will be executed by 2851 U-Boot's command interpreter; this feature is especially 2852 useful when you configure U-Boot to use a real shell (hush) 2853 as command interpreter. 2854 2855 2856Standalone HOWTO: 2857================= 2858 2859One of the features of U-Boot is that you can dynamically load and 2860run "standalone" applications, which can use some resources of 2861U-Boot like console I/O functions or interrupt services. 2862 2863Two simple examples are included with the sources: 2864 2865"Hello World" Demo: 2866------------------- 2867 2868'examples/hello_world.c' contains a small "Hello World" Demo 2869application; it is automatically compiled when you build U-Boot. 2870It's configured to run at address 0x00040004, so you can play with it 2871like that: 2872 2873 => loads 2874 ## Ready for S-Record download ... 2875 ~>examples/hello_world.srec 2876 1 2 3 4 5 6 7 8 9 10 11 ... 2877 [file transfer complete] 2878 [connected] 2879 ## Start Addr = 0x00040004 2880 2881 => go 40004 Hello World! This is a test. 2882 ## Starting application at 0x00040004 ... 2883 Hello World 2884 argc = 7 2885 argv[0] = "40004" 2886 argv[1] = "Hello" 2887 argv[2] = "World!" 2888 argv[3] = "This" 2889 argv[4] = "is" 2890 argv[5] = "a" 2891 argv[6] = "test." 2892 argv[7] = "<NULL>" 2893 Hit any key to exit ... 2894 2895 ## Application terminated, rc = 0x0 2896 2897Another example, which demonstrates how to register a CPM interrupt 2898handler with the U-Boot code, can be found in 'examples/timer.c'. 2899Here, a CPM timer is set up to generate an interrupt every second. 2900The interrupt service routine is trivial, just printing a '.' 2901character, but this is just a demo program. The application can be 2902controlled by the following keys: 2903 2904 ? - print current values og the CPM Timer registers 2905 b - enable interrupts and start timer 2906 e - stop timer and disable interrupts 2907 q - quit application 2908 2909 => loads 2910 ## Ready for S-Record download ... 2911 ~>examples/timer.srec 2912 1 2 3 4 5 6 7 8 9 10 11 ... 2913 [file transfer complete] 2914 [connected] 2915 ## Start Addr = 0x00040004 2916 2917 => go 40004 2918 ## Starting application at 0x00040004 ... 2919 TIMERS=0xfff00980 2920 Using timer 1 2921 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2922 2923Hit 'b': 2924 [q, b, e, ?] Set interval 1000000 us 2925 Enabling timer 2926Hit '?': 2927 [q, b, e, ?] ........ 2928 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2929Hit '?': 2930 [q, b, e, ?] . 2931 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2932Hit '?': 2933 [q, b, e, ?] . 2934 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2935Hit '?': 2936 [q, b, e, ?] . 2937 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2938Hit 'e': 2939 [q, b, e, ?] ...Stopping timer 2940Hit 'q': 2941 [q, b, e, ?] ## Application terminated, rc = 0x0 2942 2943 2944Minicom warning: 2945================ 2946 2947Over time, many people have reported problems when trying to use the 2948"minicom" terminal emulation program for serial download. I (wd) 2949consider minicom to be broken, and recommend not to use it. Under 2950Unix, I recommend to use C-Kermit for general purpose use (and 2951especially for kermit binary protocol download ("loadb" command), and 2952use "cu" for S-Record download ("loads" command). 2953 2954Nevertheless, if you absolutely want to use it try adding this 2955configuration to your "File transfer protocols" section: 2956 2957 Name Program Name U/D FullScr IO-Red. Multi 2958 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2959 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2960 2961 2962NetBSD Notes: 2963============= 2964 2965Starting at version 0.9.2, U-Boot supports NetBSD both as host 2966(build U-Boot) and target system (boots NetBSD/mpc8xx). 2967 2968Building requires a cross environment; it is known to work on 2969NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2970need gmake since the Makefiles are not compatible with BSD make). 2971Note that the cross-powerpc package does not install include files; 2972attempting to build U-Boot will fail because <machine/ansi.h> is 2973missing. This file has to be installed and patched manually: 2974 2975 # cd /usr/pkg/cross/powerpc-netbsd/include 2976 # mkdir powerpc 2977 # ln -s powerpc machine 2978 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2979 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2980 2981Native builds *don't* work due to incompatibilities between native 2982and U-Boot include files. 2983 2984Booting assumes that (the first part of) the image booted is a 2985stage-2 loader which in turn loads and then invokes the kernel 2986proper. Loader sources will eventually appear in the NetBSD source 2987tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2988meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2989details. 2990 2991 2992Implementation Internals: 2993========================= 2994 2995The following is not intended to be a complete description of every 2996implementation detail. However, it should help to understand the 2997inner workings of U-Boot and make it easier to port it to custom 2998hardware. 2999 3000 3001Initial Stack, Global Data: 3002--------------------------- 3003 3004The implementation of U-Boot is complicated by the fact that U-Boot 3005starts running out of ROM (flash memory), usually without access to 3006system RAM (because the memory controller is not initialized yet). 3007This means that we don't have writable Data or BSS segments, and BSS 3008is not initialized as zero. To be able to get a C environment working 3009at all, we have to allocate at least a minimal stack. Implementation 3010options for this are defined and restricted by the CPU used: Some CPU 3011models provide on-chip memory (like the IMMR area on MPC8xx and 3012MPC826x processors), on others (parts of) the data cache can be 3013locked as (mis-) used as memory, etc. 3014 3015 Chris Hallinan posted a good summary of these issues to the 3016 u-boot-users mailing list: 3017 3018 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 3019 From: "Chris Hallinan" <clh@net1plus.com> 3020 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 3021 ... 3022 3023 Correct me if I'm wrong, folks, but the way I understand it 3024 is this: Using DCACHE as initial RAM for Stack, etc, does not 3025 require any physical RAM backing up the cache. The cleverness 3026 is that the cache is being used as a temporary supply of 3027 necessary storage before the SDRAM controller is setup. It's 3028 beyond the scope of this list to expain the details, but you 3029 can see how this works by studying the cache architecture and 3030 operation in the architecture and processor-specific manuals. 3031 3032 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3033 is another option for the system designer to use as an 3034 initial stack/ram area prior to SDRAM being available. Either 3035 option should work for you. Using CS 4 should be fine if your 3036 board designers haven't used it for something that would 3037 cause you grief during the initial boot! It is frequently not 3038 used. 3039 3040 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3041 with your processor/board/system design. The default value 3042 you will find in any recent u-boot distribution in 3043 Walnut405.h should work for you. I'd set it to a value larger 3044 than your SDRAM module. If you have a 64MB SDRAM module, set 3045 it above 400_0000. Just make sure your board has no resources 3046 that are supposed to respond to that address! That code in 3047 start.S has been around a while and should work as is when 3048 you get the config right. 3049 3050 -Chris Hallinan 3051 DS4.COM, Inc. 3052 3053It is essential to remember this, since it has some impact on the C 3054code for the initialization procedures: 3055 3056* Initialized global data (data segment) is read-only. Do not attempt 3057 to write it. 3058 3059* Do not use any unitialized global data (or implicitely initialized 3060 as zero data - BSS segment) at all - this is undefined, initiali- 3061 zation is performed later (when relocating to RAM). 3062 3063* Stack space is very limited. Avoid big data buffers or things like 3064 that. 3065 3066Having only the stack as writable memory limits means we cannot use 3067normal global data to share information beween the code. But it 3068turned out that the implementation of U-Boot can be greatly 3069simplified by making a global data structure (gd_t) available to all 3070functions. We could pass a pointer to this data as argument to _all_ 3071functions, but this would bloat the code. Instead we use a feature of 3072the GCC compiler (Global Register Variables) to share the data: we 3073place a pointer (gd) to the global data into a register which we 3074reserve for this purpose. 3075 3076When choosing a register for such a purpose we are restricted by the 3077relevant (E)ABI specifications for the current architecture, and by 3078GCC's implementation. 3079 3080For PowerPC, the following registers have specific use: 3081 R1: stack pointer 3082 R2: TOC pointer 3083 R3-R4: parameter passing and return values 3084 R5-R10: parameter passing 3085 R13: small data area pointer 3086 R30: GOT pointer 3087 R31: frame pointer 3088 3089 (U-Boot also uses R14 as internal GOT pointer.) 3090 3091 ==> U-Boot will use R29 to hold a pointer to the global data 3092 3093 Note: on PPC, we could use a static initializer (since the 3094 address of the global data structure is known at compile time), 3095 but it turned out that reserving a register results in somewhat 3096 smaller code - although the code savings are not that big (on 3097 average for all boards 752 bytes for the whole U-Boot image, 3098 624 text + 127 data). 3099 3100On ARM, the following registers are used: 3101 3102 R0: function argument word/integer result 3103 R1-R3: function argument word 3104 R9: GOT pointer 3105 R10: stack limit (used only if stack checking if enabled) 3106 R11: argument (frame) pointer 3107 R12: temporary workspace 3108 R13: stack pointer 3109 R14: link register 3110 R15: program counter 3111 3112 ==> U-Boot will use R8 to hold a pointer to the global data 3113 3114 3115Memory Management: 3116------------------ 3117 3118U-Boot runs in system state and uses physical addresses, i.e. the 3119MMU is not used either for address mapping nor for memory protection. 3120 3121The available memory is mapped to fixed addresses using the memory 3122controller. In this process, a contiguous block is formed for each 3123memory type (Flash, SDRAM, SRAM), even when it consists of several 3124physical memory banks. 3125 3126U-Boot is installed in the first 128 kB of the first Flash bank (on 3127TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3128booting and sizing and initializing DRAM, the code relocates itself 3129to the upper end of DRAM. Immediately below the U-Boot code some 3130memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3131configuration setting]. Below that, a structure with global Board 3132Info data is placed, followed by the stack (growing downward). 3133 3134Additionally, some exception handler code is copied to the low 8 kB 3135of DRAM (0x00000000 ... 0x00001FFF). 3136 3137So a typical memory configuration with 16 MB of DRAM could look like 3138this: 3139 3140 0x0000 0000 Exception Vector code 3141 : 3142 0x0000 1FFF 3143 0x0000 2000 Free for Application Use 3144 : 3145 : 3146 3147 : 3148 : 3149 0x00FB FF20 Monitor Stack (Growing downward) 3150 0x00FB FFAC Board Info Data and permanent copy of global data 3151 0x00FC 0000 Malloc Arena 3152 : 3153 0x00FD FFFF 3154 0x00FE 0000 RAM Copy of Monitor Code 3155 ... eventually: LCD or video framebuffer 3156 ... eventually: pRAM (Protected RAM - unchanged by reset) 3157 0x00FF FFFF [End of RAM] 3158 3159 3160System Initialization: 3161---------------------- 3162 3163In the reset configuration, U-Boot starts at the reset entry point 3164(on most PowerPC systens at address 0x00000100). Because of the reset 3165configuration for CS0# this is a mirror of the onboard Flash memory. 3166To be able to re-map memory U-Boot then jumps to its link address. 3167To be able to implement the initialization code in C, a (small!) 3168initial stack is set up in the internal Dual Ported RAM (in case CPUs 3169which provide such a feature like MPC8xx or MPC8260), or in a locked 3170part of the data cache. After that, U-Boot initializes the CPU core, 3171the caches and the SIU. 3172 3173Next, all (potentially) available memory banks are mapped using a 3174preliminary mapping. For example, we put them on 512 MB boundaries 3175(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3176on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3177programmed for SDRAM access. Using the temporary configuration, a 3178simple memory test is run that determines the size of the SDRAM 3179banks. 3180 3181When there is more than one SDRAM bank, and the banks are of 3182different size, the largest is mapped first. For equal size, the first 3183bank (CS2#) is mapped first. The first mapping is always for address 31840x00000000, with any additional banks following immediately to create 3185contiguous memory starting from 0. 3186 3187Then, the monitor installs itself at the upper end of the SDRAM area 3188and allocates memory for use by malloc() and for the global Board 3189Info data; also, the exception vector code is copied to the low RAM 3190pages, and the final stack is set up. 3191 3192Only after this relocation will you have a "normal" C environment; 3193until that you are restricted in several ways, mostly because you are 3194running from ROM, and because the code will have to be relocated to a 3195new address in RAM. 3196 3197 3198U-Boot Porting Guide: 3199---------------------- 3200 3201[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3202list, October 2002] 3203 3204 3205int main (int argc, char *argv[]) 3206{ 3207 sighandler_t no_more_time; 3208 3209 signal (SIGALRM, no_more_time); 3210 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3211 3212 if (available_money > available_manpower) { 3213 pay consultant to port U-Boot; 3214 return 0; 3215 } 3216 3217 Download latest U-Boot source; 3218 3219 Subscribe to u-boot-users mailing list; 3220 3221 if (clueless) { 3222 email ("Hi, I am new to U-Boot, how do I get started?"); 3223 } 3224 3225 while (learning) { 3226 Read the README file in the top level directory; 3227 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3228 Read the source, Luke; 3229 } 3230 3231 if (available_money > toLocalCurrency ($2500)) { 3232 Buy a BDI2000; 3233 } else { 3234 Add a lot of aggravation and time; 3235 } 3236 3237 Create your own board support subdirectory; 3238 3239 Create your own board config file; 3240 3241 while (!running) { 3242 do { 3243 Add / modify source code; 3244 } until (compiles); 3245 Debug; 3246 if (clueless) 3247 email ("Hi, I am having problems..."); 3248 } 3249 Send patch file to Wolfgang; 3250 3251 return 0; 3252} 3253 3254void no_more_time (int sig) 3255{ 3256 hire_a_guru(); 3257} 3258 3259 3260Coding Standards: 3261----------------- 3262 3263All contributions to U-Boot should conform to the Linux kernel 3264coding style; see the file "Documentation/CodingStyle" in your Linux 3265kernel source directory. 3266 3267Please note that U-Boot is implemented in C (and to some small parts 3268in Assembler); no C++ is used, so please do not use C++ style 3269comments (//) in your code. 3270 3271Please also stick to the following formatting rules: 3272- remove any trailing white space 3273- use TAB characters for indentation, not spaces 3274- make sure NOT to use DOS '\r\n' line feeds 3275- do not add more than 2 empty lines to source files 3276- do not add trailing empty lines to source files 3277 3278Submissions which do not conform to the standards may be returned 3279with a request to reformat the changes. 3280 3281 3282Submitting Patches: 3283------------------- 3284 3285Since the number of patches for U-Boot is growing, we need to 3286establish some rules. Submissions which do not conform to these rules 3287may be rejected, even when they contain important and valuable stuff. 3288 3289 3290When you send a patch, please include the following information with 3291it: 3292 3293* For bug fixes: a description of the bug and how your patch fixes 3294 this bug. Please try to include a way of demonstrating that the 3295 patch actually fixes something. 3296 3297* For new features: a description of the feature and your 3298 implementation. 3299 3300* A CHANGELOG entry as plaintext (separate from the patch) 3301 3302* For major contributions, your entry to the CREDITS file 3303 3304* When you add support for a new board, don't forget to add this 3305 board to the MAKEALL script, too. 3306 3307* If your patch adds new configuration options, don't forget to 3308 document these in the README file. 3309 3310* The patch itself. If you are accessing the CVS repository use "cvs 3311 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3312 version of diff does not support these options, then get the latest 3313 version of GNU diff. 3314 3315 The current directory when running this command shall be the top 3316 level directory of the U-Boot source tree, or it's parent directory 3317 (i. e. please make sure that your patch includes sufficient 3318 directory information for the affected files). 3319 3320 We accept patches as plain text, MIME attachments or as uuencoded 3321 gzipped text. 3322 3323* If one logical set of modifications affects or creates several 3324 files, all these changes shall be submitted in a SINGLE patch file. 3325 3326* Changesets that contain different, unrelated modifications shall be 3327 submitted as SEPARATE patches, one patch per changeset. 3328 3329 3330Notes: 3331 3332* Before sending the patch, run the MAKEALL script on your patched 3333 source tree and make sure that no errors or warnings are reported 3334 for any of the boards. 3335 3336* Keep your modifications to the necessary minimum: A patch 3337 containing several unrelated changes or arbitrary reformats will be 3338 returned with a request to re-formatting / split it. 3339 3340* If you modify existing code, make sure that your new code does not 3341 add to the memory footprint of the code ;-) Small is beautiful! 3342 When adding new features, these should compile conditionally only 3343 (using #ifdef), and the resulting code with the new feature 3344 disabled must not need more memory than the old code without your 3345 modification. 3346