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_LUBBOCK, CONFIG_SHANNON, CONFIG_SMDK2400, 298 CONFIG_SMDK2410, CONFIG_TRAB, CONFIG_VCMA9, 299 300 MicroBlaze based boards: 301 ------------------------ 302 303 CONFIG_SUZAKU 304 305 306- CPU Module Type: (if CONFIG_COGENT is defined) 307 Define exactly one of 308 CONFIG_CMA286_60_OLD 309--- FIXME --- not tested yet: 310 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 311 CONFIG_CMA287_23, CONFIG_CMA287_50 312 313- Motherboard Type: (if CONFIG_COGENT is defined) 314 Define exactly one of 315 CONFIG_CMA101, CONFIG_CMA102 316 317- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 318 Define one or more of 319 CONFIG_CMA302 320 321- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 322 Define one or more of 323 CONFIG_LCD_HEARTBEAT - update a character position on 324 the lcd display every second with 325 a "rotator" |\-/|\-/ 326 327- Board flavour: (if CONFIG_MPC8260ADS is defined) 328 CONFIG_ADSTYPE 329 Possible values are: 330 CFG_8260ADS - original MPC8260ADS 331 CFG_8266ADS - MPC8266ADS 332 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR 333 CFG_8272ADS - MPC8272ADS 334 335- MPC824X Family Member (if CONFIG_MPC824X is defined) 336 Define exactly one of 337 CONFIG_MPC8240, CONFIG_MPC8245 338 339- 8xx CPU Options: (if using an MPC8xx cpu) 340 Define one or more of 341 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work 342 e.g. if there is no 32KHz 343 reference PIT/RTC clock 344 345- 859/866 CPU options: (if using a MPC859 or MPC866 CPU): 346 CFG_866_OSCCLK 347 CFG_866_CPUCLK_MIN 348 CFG_866_CPUCLK_MAX 349 CFG_866_CPUCLK_DEFAULT 350 See doc/README.MPC866 351 352 CFG_MEASURE_CPUCLK 353 354 Define this to measure the actual CPU clock instead 355 of relying on the correctness of the configured 356 values. Mostly useful for board bringup to make sure 357 the PLL is locked at the intended frequency. Note 358 that this requires a (stable) reference clock (32 kHz 359 RTC clock), 360 361- Linux Kernel Interface: 362 CONFIG_CLOCKS_IN_MHZ 363 364 U-Boot stores all clock information in Hz 365 internally. For binary compatibility with older Linux 366 kernels (which expect the clocks passed in the 367 bd_info data to be in MHz) the environment variable 368 "clocks_in_mhz" can be defined so that U-Boot 369 converts clock data to MHZ before passing it to the 370 Linux kernel. 371 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 372 "clocks_in_mhz=1" is automatically included in the 373 default environment. 374 375 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 376 377 When transfering memsize parameter to linux, some versions 378 expect it to be in bytes, others in MB. 379 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 380 381- Console Interface: 382 Depending on board, define exactly one serial port 383 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 384 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 385 console by defining CONFIG_8xx_CONS_NONE 386 387 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 388 port routines must be defined elsewhere 389 (i.e. serial_init(), serial_getc(), ...) 390 391 CONFIG_CFB_CONSOLE 392 Enables console device for a color framebuffer. Needs following 393 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 394 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 395 (default big endian) 396 VIDEO_HW_RECTFILL graphic chip supports 397 rectangle fill 398 (cf. smiLynxEM) 399 VIDEO_HW_BITBLT graphic chip supports 400 bit-blit (cf. smiLynxEM) 401 VIDEO_VISIBLE_COLS visible pixel columns 402 (cols=pitch) 403 VIDEO_VISIBLE_ROWS visible pixel rows 404 VIDEO_PIXEL_SIZE bytes per pixel 405 VIDEO_DATA_FORMAT graphic data format 406 (0-5, cf. cfb_console.c) 407 VIDEO_FB_ADRS framebuffer address 408 VIDEO_KBD_INIT_FCT keyboard int fct 409 (i.e. i8042_kbd_init()) 410 VIDEO_TSTC_FCT test char fct 411 (i.e. i8042_tstc) 412 VIDEO_GETC_FCT get char fct 413 (i.e. i8042_getc) 414 CONFIG_CONSOLE_CURSOR cursor drawing on/off 415 (requires blink timer 416 cf. i8042.c) 417 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 418 CONFIG_CONSOLE_TIME display time/date info in 419 upper right corner 420 (requires CFG_CMD_DATE) 421 CONFIG_VIDEO_LOGO display Linux logo in 422 upper left corner 423 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 424 linux_logo.h for logo. 425 Requires CONFIG_VIDEO_LOGO 426 CONFIG_CONSOLE_EXTRA_INFO 427 addional board info beside 428 the logo 429 430 When CONFIG_CFB_CONSOLE is defined, video console is 431 default i/o. Serial console can be forced with 432 environment 'console=serial'. 433 434 When CONFIG_SILENT_CONSOLE is defined, all console 435 messages (by U-Boot and Linux!) can be silenced with 436 the "silent" environment variable. See 437 doc/README.silent for more information. 438 439- Console Baudrate: 440 CONFIG_BAUDRATE - in bps 441 Select one of the baudrates listed in 442 CFG_BAUDRATE_TABLE, see below. 443 CFG_BRGCLK_PRESCALE, baudrate prescale 444 445- Interrupt driven serial port input: 446 CONFIG_SERIAL_SOFTWARE_FIFO 447 448 PPC405GP only. 449 Use an interrupt handler for receiving data on the 450 serial port. It also enables using hardware handshake 451 (RTS/CTS) and UART's built-in FIFO. Set the number of 452 bytes the interrupt driven input buffer should have. 453 454 Leave undefined to disable this feature, including 455 disable the buffer and hardware handshake. 456 457- Console UART Number: 458 CONFIG_UART1_CONSOLE 459 460 IBM PPC4xx only. 461 If defined internal UART1 (and not UART0) is used 462 as default U-Boot console. 463 464- Boot Delay: CONFIG_BOOTDELAY - in seconds 465 Delay before automatically booting the default image; 466 set to -1 to disable autoboot. 467 468 See doc/README.autoboot for these options that 469 work with CONFIG_BOOTDELAY. None are required. 470 CONFIG_BOOT_RETRY_TIME 471 CONFIG_BOOT_RETRY_MIN 472 CONFIG_AUTOBOOT_KEYED 473 CONFIG_AUTOBOOT_PROMPT 474 CONFIG_AUTOBOOT_DELAY_STR 475 CONFIG_AUTOBOOT_STOP_STR 476 CONFIG_AUTOBOOT_DELAY_STR2 477 CONFIG_AUTOBOOT_STOP_STR2 478 CONFIG_ZERO_BOOTDELAY_CHECK 479 CONFIG_RESET_TO_RETRY 480 481- Autoboot Command: 482 CONFIG_BOOTCOMMAND 483 Only needed when CONFIG_BOOTDELAY is enabled; 484 define a command string that is automatically executed 485 when no character is read on the console interface 486 within "Boot Delay" after reset. 487 488 CONFIG_BOOTARGS 489 This can be used to pass arguments to the bootm 490 command. The value of CONFIG_BOOTARGS goes into the 491 environment value "bootargs". 492 493 CONFIG_RAMBOOT and CONFIG_NFSBOOT 494 The value of these goes into the environment as 495 "ramboot" and "nfsboot" respectively, and can be used 496 as a convenience, when switching between booting from 497 ram and nfs. 498 499- Pre-Boot Commands: 500 CONFIG_PREBOOT 501 502 When this option is #defined, the existence of the 503 environment variable "preboot" will be checked 504 immediately before starting the CONFIG_BOOTDELAY 505 countdown and/or running the auto-boot command resp. 506 entering interactive mode. 507 508 This feature is especially useful when "preboot" is 509 automatically generated or modified. For an example 510 see the LWMON board specific code: here "preboot" is 511 modified when the user holds down a certain 512 combination of keys on the (special) keyboard when 513 booting the systems 514 515- Serial Download Echo Mode: 516 CONFIG_LOADS_ECHO 517 If defined to 1, all characters received during a 518 serial download (using the "loads" command) are 519 echoed back. This might be needed by some terminal 520 emulations (like "cu"), but may as well just take 521 time on others. This setting #define's the initial 522 value of the "loads_echo" environment variable. 523 524- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 525 CONFIG_KGDB_BAUDRATE 526 Select one of the baudrates listed in 527 CFG_BAUDRATE_TABLE, see below. 528 529- Monitor Functions: 530 CONFIG_COMMANDS 531 Most monitor functions can be selected (or 532 de-selected) by adjusting the definition of 533 CONFIG_COMMANDS; to select individual functions, 534 #define CONFIG_COMMANDS by "OR"ing any of the 535 following values: 536 537 #define enables commands: 538 ------------------------- 539 CFG_CMD_ASKENV * ask for env variable 540 CFG_CMD_AUTOSCRIPT Autoscript Support 541 CFG_CMD_BDI bdinfo 542 CFG_CMD_BEDBUG Include BedBug Debugger 543 CFG_CMD_BMP * BMP support 544 CFG_CMD_BOOTD bootd 545 CFG_CMD_CACHE icache, dcache 546 CFG_CMD_CONSOLE coninfo 547 CFG_CMD_DATE * support for RTC, date/time... 548 CFG_CMD_DHCP DHCP support 549 CFG_CMD_DIAG * Diagnostics 550 CFG_CMD_DOC * Disk-On-Chip Support 551 CFG_CMD_DTT Digital Therm and Thermostat 552 CFG_CMD_ECHO * echo arguments 553 CFG_CMD_EEPROM * EEPROM read/write support 554 CFG_CMD_ELF bootelf, bootvx 555 CFG_CMD_ENV saveenv 556 CFG_CMD_FDC * Floppy Disk Support 557 CFG_CMD_FAT FAT partition support 558 CFG_CMD_FDOS * Dos diskette Support 559 CFG_CMD_FLASH flinfo, erase, protect 560 CFG_CMD_FPGA FPGA device initialization support 561 CFG_CMD_HWFLOW * RTS/CTS hw flow control 562 CFG_CMD_I2C * I2C serial bus support 563 CFG_CMD_IDE * IDE harddisk support 564 CFG_CMD_IMI iminfo 565 CFG_CMD_IMLS List all found images 566 CFG_CMD_IMMAP * IMMR dump support 567 CFG_CMD_IRQ * irqinfo 568 CFG_CMD_ITEST * Integer/string test of 2 values 569 CFG_CMD_JFFS2 * JFFS2 Support 570 CFG_CMD_KGDB * kgdb 571 CFG_CMD_LOADB loadb 572 CFG_CMD_LOADS loads 573 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 574 loop, mtest 575 CFG_CMD_MISC Misc functions like sleep etc 576 CFG_CMD_MMC MMC memory mapped support 577 CFG_CMD_MII MII utility commands 578 CFG_CMD_NAND * NAND support 579 CFG_CMD_NET bootp, tftpboot, rarpboot 580 CFG_CMD_PCI * pciinfo 581 CFG_CMD_PCMCIA * PCMCIA support 582 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host 583 CFG_CMD_PORTIO * Port I/O 584 CFG_CMD_REGINFO * Register dump 585 CFG_CMD_RUN run command in env variable 586 CFG_CMD_SAVES save S record dump 587 CFG_CMD_SCSI * SCSI Support 588 CFG_CMD_SDRAM * print SDRAM configuration information 589 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 590 CFG_CMD_SPI * SPI serial bus support 591 CFG_CMD_USB * USB support 592 CFG_CMD_VFD * VFD support (TRAB) 593 CFG_CMD_BSP * Board SPecific functions 594 CFG_CMD_CDP * Cisco Discover Protocol support 595 ----------------------------------------------- 596 CFG_CMD_ALL all 597 598 CFG_CMD_DFL Default configuration; at the moment 599 this is includes all commands, except 600 the ones marked with "*" in the list 601 above. 602 603 If you don't define CONFIG_COMMANDS it defaults to 604 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 605 override the default settings in the respective 606 include file. 607 608 EXAMPLE: If you want all functions except of network 609 support you can write: 610 611 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 612 613 614 Note: Don't enable the "icache" and "dcache" commands 615 (configuration option CFG_CMD_CACHE) unless you know 616 what you (and your U-Boot users) are doing. Data 617 cache cannot be enabled on systems like the 8xx or 618 8260 (where accesses to the IMMR region must be 619 uncached), and it cannot be disabled on all other 620 systems where we (mis-) use the data cache to hold an 621 initial stack and some data. 622 623 624 XXX - this list needs to get updated! 625 626- Watchdog: 627 CONFIG_WATCHDOG 628 If this variable is defined, it enables watchdog 629 support. There must be support in the platform specific 630 code for a watchdog. For the 8xx and 8260 CPUs, the 631 SIU Watchdog feature is enabled in the SYPCR 632 register. 633 634- U-Boot Version: 635 CONFIG_VERSION_VARIABLE 636 If this variable is defined, an environment variable 637 named "ver" is created by U-Boot showing the U-Boot 638 version as printed by the "version" command. 639 This variable is readonly. 640 641- Real-Time Clock: 642 643 When CFG_CMD_DATE is selected, the type of the RTC 644 has to be selected, too. Define exactly one of the 645 following options: 646 647 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 648 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 649 CONFIG_RTC_MC146818 - use MC146818 RTC 650 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 651 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 652 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 653 CONFIG_RTC_DS164x - use Dallas DS164x RTC 654 655 Note that if the RTC uses I2C, then the I2C interface 656 must also be configured. See I2C Support, below. 657 658- Timestamp Support: 659 660 When CONFIG_TIMESTAMP is selected, the timestamp 661 (date and time) of an image is printed by image 662 commands like bootm or iminfo. This option is 663 automatically enabled when you select CFG_CMD_DATE . 664 665- Partition Support: 666 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 667 and/or CONFIG_ISO_PARTITION 668 669 If IDE or SCSI support is enabled (CFG_CMD_IDE or 670 CFG_CMD_SCSI) you must configure support for at least 671 one partition type as well. 672 673- IDE Reset method: 674 CONFIG_IDE_RESET_ROUTINE - this is defined in several 675 board configurations files but used nowhere! 676 677 CONFIG_IDE_RESET - is this is defined, IDE Reset will 678 be performed by calling the function 679 ide_set_reset(int reset) 680 which has to be defined in a board specific file 681 682- ATAPI Support: 683 CONFIG_ATAPI 684 685 Set this to enable ATAPI support. 686 687- LBA48 Support 688 CONFIG_LBA48 689 690 Set this to enable support for disks larger than 137GB 691 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 692 Whithout these , LBA48 support uses 32bit variables and will 'only' 693 support disks up to 2.1TB. 694 695 CFG_64BIT_LBA: 696 When enabled, makes the IDE subsystem use 64bit sector addresses. 697 Default is 32bit. 698 699- SCSI Support: 700 At the moment only there is only support for the 701 SYM53C8XX SCSI controller; define 702 CONFIG_SCSI_SYM53C8XX to enable it. 703 704 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 705 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 706 CFG_SCSI_MAX_LUN] can be adjusted to define the 707 maximum numbers of LUNs, SCSI ID's and target 708 devices. 709 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 710 711- NETWORK Support (PCI): 712 CONFIG_E1000 713 Support for Intel 8254x gigabit chips. 714 715 CONFIG_EEPRO100 716 Support for Intel 82557/82559/82559ER chips. 717 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 718 write routine for first time initialisation. 719 720 CONFIG_TULIP 721 Support for Digital 2114x chips. 722 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 723 modem chip initialisation (KS8761/QS6611). 724 725 CONFIG_NATSEMI 726 Support for National dp83815 chips. 727 728 CONFIG_NS8382X 729 Support for National dp8382[01] gigabit chips. 730 731- NETWORK Support (other): 732 733 CONFIG_DRIVER_LAN91C96 734 Support for SMSC's LAN91C96 chips. 735 736 CONFIG_LAN91C96_BASE 737 Define this to hold the physical address 738 of the LAN91C96's I/O space 739 740 CONFIG_LAN91C96_USE_32_BIT 741 Define this to enable 32 bit addressing 742 743- USB Support: 744 At the moment only the UHCI host controller is 745 supported (PIP405, MIP405, MPC5200); define 746 CONFIG_USB_UHCI to enable it. 747 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 748 end define CONFIG_USB_STORAGE to enable the USB 749 storage devices. 750 Note: 751 Supported are USB Keyboards and USB Floppy drives 752 (TEAC FD-05PUB). 753 MPC5200 USB requires additional defines: 754 CONFIG_USB_CLOCK 755 for 528 MHz Clock: 0x0001bbbb 756 CONFIG_USB_CONFIG 757 for differential drivers: 0x00001000 758 for single ended drivers: 0x00005000 759 760 761- MMC Support: 762 The MMC controller on the Intel PXA is supported. To 763 enable this define CONFIG_MMC. The MMC can be 764 accessed from the boot prompt by mapping the device 765 to physical memory similar to flash. Command line is 766 enabled with CFG_CMD_MMC. The MMC driver also works with 767 the FAT fs. This is enabled with CFG_CMD_FAT. 768 769- Keyboard Support: 770 CONFIG_ISA_KEYBOARD 771 772 Define this to enable standard (PC-Style) keyboard 773 support 774 775 CONFIG_I8042_KBD 776 Standard PC keyboard driver with US (is default) and 777 GERMAN key layout (switch via environment 'keymap=de') support. 778 Export function i8042_kbd_init, i8042_tstc and i8042_getc 779 for cfb_console. Supports cursor blinking. 780 781- Video support: 782 CONFIG_VIDEO 783 784 Define this to enable video support (for output to 785 video). 786 787 CONFIG_VIDEO_CT69000 788 789 Enable Chips & Technologies 69000 Video chip 790 791 CONFIG_VIDEO_SMI_LYNXEM 792 Enable Silicon Motion SMI 712/710/810 Video chip. The 793 video output is selected via environment 'videoout' 794 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 795 assumed. 796 797 For the CT69000 and SMI_LYNXEM drivers, videomode is 798 selected via environment 'videomode'. Two diferent ways 799 are possible: 800 - "videomode=num" 'num' is a standard LiLo mode numbers. 801 Following standard modes are supported (* is default): 802 803 Colors 640x480 800x600 1024x768 1152x864 1280x1024 804 -------------+--------------------------------------------- 805 8 bits | 0x301* 0x303 0x305 0x161 0x307 806 15 bits | 0x310 0x313 0x316 0x162 0x319 807 16 bits | 0x311 0x314 0x317 0x163 0x31A 808 24 bits | 0x312 0x315 0x318 ? 0x31B 809 -------------+--------------------------------------------- 810 (i.e. setenv videomode 317; saveenv; reset;) 811 812 - "videomode=bootargs" all the video parameters are parsed 813 from the bootargs. (See drivers/videomodes.c) 814 815 816 CONFIG_VIDEO_SED13806 817 Enable Epson SED13806 driver. This driver supports 8bpp 818 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 819 or CONFIG_VIDEO_SED13806_16BPP 820 821- Keyboard Support: 822 CONFIG_KEYBOARD 823 824 Define this to enable a custom keyboard support. 825 This simply calls drv_keyboard_init() which must be 826 defined in your board-specific files. 827 The only board using this so far is RBC823. 828 829- LCD Support: CONFIG_LCD 830 831 Define this to enable LCD support (for output to LCD 832 display); also select one of the supported displays 833 by defining one of these: 834 835 CONFIG_NEC_NL6448AC33: 836 837 NEC NL6448AC33-18. Active, color, single scan. 838 839 CONFIG_NEC_NL6448BC20 840 841 NEC NL6448BC20-08. 6.5", 640x480. 842 Active, color, single scan. 843 844 CONFIG_NEC_NL6448BC33_54 845 846 NEC NL6448BC33-54. 10.4", 640x480. 847 Active, color, single scan. 848 849 CONFIG_SHARP_16x9 850 851 Sharp 320x240. Active, color, single scan. 852 It isn't 16x9, and I am not sure what it is. 853 854 CONFIG_SHARP_LQ64D341 855 856 Sharp LQ64D341 display, 640x480. 857 Active, color, single scan. 858 859 CONFIG_HLD1045 860 861 HLD1045 display, 640x480. 862 Active, color, single scan. 863 864 CONFIG_OPTREX_BW 865 866 Optrex CBL50840-2 NF-FW 99 22 M5 867 or 868 Hitachi LMG6912RPFC-00T 869 or 870 Hitachi SP14Q002 871 872 320x240. Black & white. 873 874 Normally display is black on white background; define 875 CFG_WHITE_ON_BLACK to get it inverted. 876 877- Splash Screen Support: CONFIG_SPLASH_SCREEN 878 879 If this option is set, the environment is checked for 880 a variable "splashimage". If found, the usual display 881 of logo, copyright and system information on the LCD 882 is supressed and the BMP image at the address 883 specified in "splashimage" is loaded instead. The 884 console is redirected to the "nulldev", too. This 885 allows for a "silent" boot where a splash screen is 886 loaded very quickly after power-on. 887 888- Compression support: 889 CONFIG_BZIP2 890 891 If this option is set, support for bzip2 compressed 892 images is included. If not, only uncompressed and gzip 893 compressed images are supported. 894 895 NOTE: the bzip2 algorithm requires a lot of RAM, so 896 the malloc area (as defined by CFG_MALLOC_LEN) should 897 be at least 4MB. 898 899- MII/PHY support: 900 CONFIG_PHY_ADDR 901 902 The address of PHY on MII bus. 903 904 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 905 906 The clock frequency of the MII bus 907 908 CONFIG_PHY_GIGE 909 910 If this option is set, support for speed/duplex 911 detection of Gigabit PHY is included. 912 913 CONFIG_PHY_RESET_DELAY 914 915 Some PHY like Intel LXT971A need extra delay after 916 reset before any MII register access is possible. 917 For such PHY, set this option to the usec delay 918 required. (minimum 300usec for LXT971A) 919 920 CONFIG_PHY_CMD_DELAY (ppc4xx) 921 922 Some PHY like Intel LXT971A need extra delay after 923 command issued before MII status register can be read 924 925- Ethernet address: 926 CONFIG_ETHADDR 927 CONFIG_ETH2ADDR 928 CONFIG_ETH3ADDR 929 930 Define a default value for ethernet address to use 931 for the respective ethernet interface, in case this 932 is not determined automatically. 933 934- IP address: 935 CONFIG_IPADDR 936 937 Define a default value for the IP address to use for 938 the default ethernet interface, in case this is not 939 determined through e.g. bootp. 940 941- Server IP address: 942 CONFIG_SERVERIP 943 944 Defines a default value for theIP address of a TFTP 945 server to contact when using the "tftboot" command. 946 947- BOOTP Recovery Mode: 948 CONFIG_BOOTP_RANDOM_DELAY 949 950 If you have many targets in a network that try to 951 boot using BOOTP, you may want to avoid that all 952 systems send out BOOTP requests at precisely the same 953 moment (which would happen for instance at recovery 954 from a power failure, when all systems will try to 955 boot, thus flooding the BOOTP server. Defining 956 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 957 inserted before sending out BOOTP requests. The 958 following delays are insterted then: 959 960 1st BOOTP request: delay 0 ... 1 sec 961 2nd BOOTP request: delay 0 ... 2 sec 962 3rd BOOTP request: delay 0 ... 4 sec 963 4th and following 964 BOOTP requests: delay 0 ... 8 sec 965 966- DHCP Advanced Options: 967 CONFIG_BOOTP_MASK 968 969 You can fine tune the DHCP functionality by adding 970 these flags to the CONFIG_BOOTP_MASK define: 971 972 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 973 serverip from a DHCP server, it is possible that more 974 than one DNS serverip is offered to the client. 975 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 976 serverip will be stored in the additional environment 977 variable "dnsip2". The first DNS serverip is always 978 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 979 is added to the CONFIG_BOOTP_MASK. 980 981 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 982 to do a dynamic update of a DNS server. To do this, they 983 need the hostname of the DHCP requester. 984 If CONFIG_BOOP_SEND_HOSTNAME is added to the 985 CONFIG_BOOTP_MASK, the content of the "hostname" 986 environment variable is passed as option 12 to 987 the DHCP server. 988 989 - CDP Options: 990 CONFIG_CDP_DEVICE_ID 991 992 The device id used in CDP trigger frames. 993 994 CONFIG_CDP_DEVICE_ID_PREFIX 995 996 A two character string which is prefixed to the MAC address 997 of the device. 998 999 CONFIG_CDP_PORT_ID 1000 1001 A printf format string which contains the ascii name of 1002 the port. Normally is set to "eth%d" which sets 1003 eth0 for the first ethernet, eth1 for the second etc. 1004 1005 CONFIG_CDP_CAPABILITIES 1006 1007 A 32bit integer which indicates the device capabilities; 1008 0x00000010 for a normal host which does not forwards. 1009 1010 CONFIG_CDP_VERSION 1011 1012 An ascii string containing the version of the software. 1013 1014 CONFIG_CDP_PLATFORM 1015 1016 An ascii string containing the name of the platform. 1017 1018 CONFIG_CDP_TRIGGER 1019 1020 A 32bit integer sent on the trigger. 1021 1022 CONFIG_CDP_POWER_CONSUMPTION 1023 1024 A 16bit integer containing the power consumption of the 1025 device in .1 of milliwatts. 1026 1027 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1028 1029 A byte containing the id of the VLAN. 1030 1031- Status LED: CONFIG_STATUS_LED 1032 1033 Several configurations allow to display the current 1034 status using a LED. For instance, the LED will blink 1035 fast while running U-Boot code, stop blinking as 1036 soon as a reply to a BOOTP request was received, and 1037 start blinking slow once the Linux kernel is running 1038 (supported by a status LED driver in the Linux 1039 kernel). Defining CONFIG_STATUS_LED enables this 1040 feature in U-Boot. 1041 1042- CAN Support: CONFIG_CAN_DRIVER 1043 1044 Defining CONFIG_CAN_DRIVER enables CAN driver support 1045 on those systems that support this (optional) 1046 feature, like the TQM8xxL modules. 1047 1048- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1049 1050 These enable I2C serial bus commands. Defining either of 1051 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1052 include the appropriate I2C driver for the selected cpu. 1053 1054 This will allow you to use i2c commands at the u-boot 1055 command line (as long as you set CFG_CMD_I2C in 1056 CONFIG_COMMANDS) and communicate with i2c based realtime 1057 clock chips. See common/cmd_i2c.c for a description of the 1058 command line interface. 1059 1060 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 1061 1062 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1063 bit-banging) driver instead of CPM or similar hardware 1064 support for I2C. 1065 1066 There are several other quantities that must also be 1067 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1068 1069 In both cases you will need to define CFG_I2C_SPEED 1070 to be the frequency (in Hz) at which you wish your i2c bus 1071 to run and CFG_I2C_SLAVE to be the address of this node (ie 1072 the cpu's i2c node address). 1073 1074 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1075 sets the cpu up as a master node and so its address should 1076 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1077 p.16-473). So, set CFG_I2C_SLAVE to 0. 1078 1079 That's all that's required for CONFIG_HARD_I2C. 1080 1081 If you use the software i2c interface (CONFIG_SOFT_I2C) 1082 then the following macros need to be defined (examples are 1083 from include/configs/lwmon.h): 1084 1085 I2C_INIT 1086 1087 (Optional). Any commands necessary to enable the I2C 1088 controller or configure ports. 1089 1090 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1091 1092 I2C_PORT 1093 1094 (Only for MPC8260 CPU). The I/O port to use (the code 1095 assumes both bits are on the same port). Valid values 1096 are 0..3 for ports A..D. 1097 1098 I2C_ACTIVE 1099 1100 The code necessary to make the I2C data line active 1101 (driven). If the data line is open collector, this 1102 define can be null. 1103 1104 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1105 1106 I2C_TRISTATE 1107 1108 The code necessary to make the I2C data line tri-stated 1109 (inactive). If the data line is open collector, this 1110 define can be null. 1111 1112 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1113 1114 I2C_READ 1115 1116 Code that returns TRUE if the I2C data line is high, 1117 FALSE if it is low. 1118 1119 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1120 1121 I2C_SDA(bit) 1122 1123 If <bit> is TRUE, sets the I2C data line high. If it 1124 is FALSE, it clears it (low). 1125 1126 eg: #define I2C_SDA(bit) \ 1127 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1128 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1129 1130 I2C_SCL(bit) 1131 1132 If <bit> is TRUE, sets the I2C clock line high. If it 1133 is FALSE, it clears it (low). 1134 1135 eg: #define I2C_SCL(bit) \ 1136 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1137 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1138 1139 I2C_DELAY 1140 1141 This delay is invoked four times per clock cycle so this 1142 controls the rate of data transfer. The data rate thus 1143 is 1 / (I2C_DELAY * 4). Often defined to be something 1144 like: 1145 1146 #define I2C_DELAY udelay(2) 1147 1148 CFG_I2C_INIT_BOARD 1149 1150 When a board is reset during an i2c bus transfer 1151 chips might think that the current transfer is still 1152 in progress. On some boards it is possible to access 1153 the i2c SCLK line directly, either by using the 1154 processor pin as a GPIO or by having a second pin 1155 connected to the bus. If this option is defined a 1156 custom i2c_init_board() routine in boards/xxx/board.c 1157 is run early in the boot sequence. 1158 1159 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1160 1161 This option enables configuration of bi_iic_fast[] flags 1162 in u-boot bd_info structure based on u-boot environment 1163 variable "i2cfast". (see also i2cfast) 1164 1165- SPI Support: CONFIG_SPI 1166 1167 Enables SPI driver (so far only tested with 1168 SPI EEPROM, also an instance works with Crystal A/D and 1169 D/As on the SACSng board) 1170 1171 CONFIG_SPI_X 1172 1173 Enables extended (16-bit) SPI EEPROM addressing. 1174 (symmetrical to CONFIG_I2C_X) 1175 1176 CONFIG_SOFT_SPI 1177 1178 Enables a software (bit-bang) SPI driver rather than 1179 using hardware support. This is a general purpose 1180 driver that only requires three general I/O port pins 1181 (two outputs, one input) to function. If this is 1182 defined, the board configuration must define several 1183 SPI configuration items (port pins to use, etc). For 1184 an example, see include/configs/sacsng.h. 1185 1186- FPGA Support: CONFIG_FPGA_COUNT 1187 1188 Specify the number of FPGA devices to support. 1189 1190 CONFIG_FPGA 1191 1192 Used to specify the types of FPGA devices. For example, 1193 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1194 1195 CFG_FPGA_PROG_FEEDBACK 1196 1197 Enable printing of hash marks during FPGA configuration. 1198 1199 CFG_FPGA_CHECK_BUSY 1200 1201 Enable checks on FPGA configuration interface busy 1202 status by the configuration function. This option 1203 will require a board or device specific function to 1204 be written. 1205 1206 CONFIG_FPGA_DELAY 1207 1208 If defined, a function that provides delays in the FPGA 1209 configuration driver. 1210 1211 CFG_FPGA_CHECK_CTRLC 1212 Allow Control-C to interrupt FPGA configuration 1213 1214 CFG_FPGA_CHECK_ERROR 1215 1216 Check for configuration errors during FPGA bitfile 1217 loading. For example, abort during Virtex II 1218 configuration if the INIT_B line goes low (which 1219 indicated a CRC error). 1220 1221 CFG_FPGA_WAIT_INIT 1222 1223 Maximum time to wait for the INIT_B line to deassert 1224 after PROB_B has been deasserted during a Virtex II 1225 FPGA configuration sequence. The default time is 500 1226 mS. 1227 1228 CFG_FPGA_WAIT_BUSY 1229 1230 Maximum time to wait for BUSY to deassert during 1231 Virtex II FPGA configuration. The default is 5 mS. 1232 1233 CFG_FPGA_WAIT_CONFIG 1234 1235 Time to wait after FPGA configuration. The default is 1236 200 mS. 1237 1238- Configuration Management: 1239 CONFIG_IDENT_STRING 1240 1241 If defined, this string will be added to the U-Boot 1242 version information (U_BOOT_VERSION) 1243 1244- Vendor Parameter Protection: 1245 1246 U-Boot considers the values of the environment 1247 variables "serial#" (Board Serial Number) and 1248 "ethaddr" (Ethernet Address) to be parameters that 1249 are set once by the board vendor / manufacturer, and 1250 protects these variables from casual modification by 1251 the user. Once set, these variables are read-only, 1252 and write or delete attempts are rejected. You can 1253 change this behviour: 1254 1255 If CONFIG_ENV_OVERWRITE is #defined in your config 1256 file, the write protection for vendor parameters is 1257 completely disabled. Anybody can change or delete 1258 these parameters. 1259 1260 Alternatively, if you #define _both_ CONFIG_ETHADDR 1261 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1262 ethernet address is installed in the environment, 1263 which can be changed exactly ONCE by the user. [The 1264 serial# is unaffected by this, i. e. it remains 1265 read-only.] 1266 1267- Protected RAM: 1268 CONFIG_PRAM 1269 1270 Define this variable to enable the reservation of 1271 "protected RAM", i. e. RAM which is not overwritten 1272 by U-Boot. Define CONFIG_PRAM to hold the number of 1273 kB you want to reserve for pRAM. You can overwrite 1274 this default value by defining an environment 1275 variable "pram" to the number of kB you want to 1276 reserve. Note that the board info structure will 1277 still show the full amount of RAM. If pRAM is 1278 reserved, a new environment variable "mem" will 1279 automatically be defined to hold the amount of 1280 remaining RAM in a form that can be passed as boot 1281 argument to Linux, for instance like that: 1282 1283 setenv bootargs ... mem=\$(mem) 1284 saveenv 1285 1286 This way you can tell Linux not to use this memory, 1287 either, which results in a memory region that will 1288 not be affected by reboots. 1289 1290 *WARNING* If your board configuration uses automatic 1291 detection of the RAM size, you must make sure that 1292 this memory test is non-destructive. So far, the 1293 following board configurations are known to be 1294 "pRAM-clean": 1295 1296 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1297 HERMES, IP860, RPXlite, LWMON, LANTEC, 1298 PCU_E, FLAGADM, TQM8260 1299 1300- Error Recovery: 1301 CONFIG_PANIC_HANG 1302 1303 Define this variable to stop the system in case of a 1304 fatal error, so that you have to reset it manually. 1305 This is probably NOT a good idea for an embedded 1306 system where you want to system to reboot 1307 automatically as fast as possible, but it may be 1308 useful during development since you can try to debug 1309 the conditions that lead to the situation. 1310 1311 CONFIG_NET_RETRY_COUNT 1312 1313 This variable defines the number of retries for 1314 network operations like ARP, RARP, TFTP, or BOOTP 1315 before giving up the operation. If not defined, a 1316 default value of 5 is used. 1317 1318- Command Interpreter: 1319 CFG_AUTO_COMPLETE 1320 1321 Enable auto completion of commands using TAB. 1322 1323 CFG_HUSH_PARSER 1324 1325 Define this variable to enable the "hush" shell (from 1326 Busybox) as command line interpreter, thus enabling 1327 powerful command line syntax like 1328 if...then...else...fi conditionals or `&&' and '||' 1329 constructs ("shell scripts"). 1330 1331 If undefined, you get the old, much simpler behaviour 1332 with a somewhat smaller memory footprint. 1333 1334 1335 CFG_PROMPT_HUSH_PS2 1336 1337 This defines the secondary prompt string, which is 1338 printed when the command interpreter needs more input 1339 to complete a command. Usually "> ". 1340 1341 Note: 1342 1343 In the current implementation, the local variables 1344 space and global environment variables space are 1345 separated. Local variables are those you define by 1346 simply typing `name=value'. To access a local 1347 variable later on, you have write `$name' or 1348 `${name}'; to execute the contents of a variable 1349 directly type `$name' at the command prompt. 1350 1351 Global environment variables are those you use 1352 setenv/printenv to work with. To run a command stored 1353 in such a variable, you need to use the run command, 1354 and you must not use the '$' sign to access them. 1355 1356 To store commands and special characters in a 1357 variable, please use double quotation marks 1358 surrounding the whole text of the variable, instead 1359 of the backslashes before semicolons and special 1360 symbols. 1361 1362- Default Environment: 1363 CONFIG_EXTRA_ENV_SETTINGS 1364 1365 Define this to contain any number of null terminated 1366 strings (variable = value pairs) that will be part of 1367 the default environment compiled into the boot image. 1368 1369 For example, place something like this in your 1370 board's config file: 1371 1372 #define CONFIG_EXTRA_ENV_SETTINGS \ 1373 "myvar1=value1\0" \ 1374 "myvar2=value2\0" 1375 1376 Warning: This method is based on knowledge about the 1377 internal format how the environment is stored by the 1378 U-Boot code. This is NOT an official, exported 1379 interface! Although it is unlikely that this format 1380 will change soon, there is no guarantee either. 1381 You better know what you are doing here. 1382 1383 Note: overly (ab)use of the default environment is 1384 discouraged. Make sure to check other ways to preset 1385 the environment like the autoscript function or the 1386 boot command first. 1387 1388- DataFlash Support: 1389 CONFIG_HAS_DATAFLASH 1390 1391 Defining this option enables DataFlash features and 1392 allows to read/write in Dataflash via the standard 1393 commands cp, md... 1394 1395- SystemACE Support: 1396 CONFIG_SYSTEMACE 1397 1398 Adding this option adds support for Xilinx SystemACE 1399 chips attached via some sort of local bus. The address 1400 of the chip must alsh be defined in the 1401 CFG_SYSTEMACE_BASE macro. For example: 1402 1403 #define CONFIG_SYSTEMACE 1404 #define CFG_SYSTEMACE_BASE 0xf0000000 1405 1406 When SystemACE support is added, the "ace" device type 1407 becomes available to the fat commands, i.e. fatls. 1408 1409- Show boot progress: 1410 CONFIG_SHOW_BOOT_PROGRESS 1411 1412 Defining this option allows to add some board- 1413 specific code (calling a user-provided function 1414 "show_boot_progress(int)") that enables you to show 1415 the system's boot progress on some display (for 1416 example, some LED's) on your board. At the moment, 1417 the following checkpoints are implemented: 1418 1419 Arg Where When 1420 1 common/cmd_bootm.c before attempting to boot an image 1421 -1 common/cmd_bootm.c Image header has bad magic number 1422 2 common/cmd_bootm.c Image header has correct magic number 1423 -2 common/cmd_bootm.c Image header has bad checksum 1424 3 common/cmd_bootm.c Image header has correct checksum 1425 -3 common/cmd_bootm.c Image data has bad checksum 1426 4 common/cmd_bootm.c Image data has correct checksum 1427 -4 common/cmd_bootm.c Image is for unsupported architecture 1428 5 common/cmd_bootm.c Architecture check OK 1429 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1430 6 common/cmd_bootm.c Image Type check OK 1431 -6 common/cmd_bootm.c gunzip uncompression error 1432 -7 common/cmd_bootm.c Unimplemented compression type 1433 7 common/cmd_bootm.c Uncompression OK 1434 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1435 8 common/cmd_bootm.c Image Type check OK 1436 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1437 9 common/cmd_bootm.c Start initial ramdisk verification 1438 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1439 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1440 10 common/cmd_bootm.c Ramdisk header is OK 1441 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1442 11 common/cmd_bootm.c Ramdisk data has correct checksum 1443 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1444 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1445 13 common/cmd_bootm.c Start multifile image verification 1446 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1447 15 common/cmd_bootm.c All preparation done, transferring control to OS 1448 1449 -30 lib_ppc/board.c Fatal error, hang the system 1450 -31 post/post.c POST test failed, detected by post_output_backlog() 1451 -32 post/post.c POST test failed, detected by post_run_single() 1452 1453 -1 common/cmd_doc.c Bad usage of "doc" command 1454 -1 common/cmd_doc.c No boot device 1455 -1 common/cmd_doc.c Unknown Chip ID on boot device 1456 -1 common/cmd_doc.c Read Error on boot device 1457 -1 common/cmd_doc.c Image header has bad magic number 1458 1459 -1 common/cmd_ide.c Bad usage of "ide" command 1460 -1 common/cmd_ide.c No boot device 1461 -1 common/cmd_ide.c Unknown boot device 1462 -1 common/cmd_ide.c Unknown partition table 1463 -1 common/cmd_ide.c Invalid partition type 1464 -1 common/cmd_ide.c Read Error on boot device 1465 -1 common/cmd_ide.c Image header has bad magic number 1466 1467 -1 common/cmd_nand.c Bad usage of "nand" command 1468 -1 common/cmd_nand.c No boot device 1469 -1 common/cmd_nand.c Unknown Chip ID on boot device 1470 -1 common/cmd_nand.c Read Error on boot device 1471 -1 common/cmd_nand.c Image header has bad magic number 1472 1473 -1 common/env_common.c Environment has a bad CRC, using default 1474 1475 1476Modem Support: 1477-------------- 1478 1479[so far only for SMDK2400 and TRAB boards] 1480 1481- Modem support endable: 1482 CONFIG_MODEM_SUPPORT 1483 1484- RTS/CTS Flow control enable: 1485 CONFIG_HWFLOW 1486 1487- Modem debug support: 1488 CONFIG_MODEM_SUPPORT_DEBUG 1489 1490 Enables debugging stuff (char screen[1024], dbg()) 1491 for modem support. Useful only with BDI2000. 1492 1493- Interrupt support (PPC): 1494 1495 There are common interrupt_init() and timer_interrupt() 1496 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1497 for cpu specific initialization. interrupt_init_cpu() 1498 should set decrementer_count to appropriate value. If 1499 cpu resets decrementer automatically after interrupt 1500 (ppc4xx) it should set decrementer_count to zero. 1501 timer_interrupt() calls timer_interrupt_cpu() for cpu 1502 specific handling. If board has watchdog / status_led 1503 / other_activity_monitor it works automatically from 1504 general timer_interrupt(). 1505 1506- General: 1507 1508 In the target system modem support is enabled when a 1509 specific key (key combination) is pressed during 1510 power-on. Otherwise U-Boot will boot normally 1511 (autoboot). The key_pressed() fuction is called from 1512 board_init(). Currently key_pressed() is a dummy 1513 function, returning 1 and thus enabling modem 1514 initialization. 1515 1516 If there are no modem init strings in the 1517 environment, U-Boot proceed to autoboot; the 1518 previous output (banner, info printfs) will be 1519 supressed, though. 1520 1521 See also: doc/README.Modem 1522 1523 1524Configuration Settings: 1525----------------------- 1526 1527- CFG_LONGHELP: Defined when you want long help messages included; 1528 undefine this when you're short of memory. 1529 1530- CFG_PROMPT: This is what U-Boot prints on the console to 1531 prompt for user input. 1532 1533- CFG_CBSIZE: Buffer size for input from the Console 1534 1535- CFG_PBSIZE: Buffer size for Console output 1536 1537- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1538 1539- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1540 the application (usually a Linux kernel) when it is 1541 booted 1542 1543- CFG_BAUDRATE_TABLE: 1544 List of legal baudrate settings for this board. 1545 1546- CFG_CONSOLE_INFO_QUIET 1547 Suppress display of console information at boot. 1548 1549- CFG_CONSOLE_IS_IN_ENV 1550 If the board specific function 1551 extern int overwrite_console (void); 1552 returns 1, the stdin, stderr and stdout are switched to the 1553 serial port, else the settings in the environment are used. 1554 1555- CFG_CONSOLE_OVERWRITE_ROUTINE 1556 Enable the call to overwrite_console(). 1557 1558- CFG_CONSOLE_ENV_OVERWRITE 1559 Enable overwrite of previous console environment settings. 1560 1561- CFG_MEMTEST_START, CFG_MEMTEST_END: 1562 Begin and End addresses of the area used by the 1563 simple memory test. 1564 1565- CFG_ALT_MEMTEST: 1566 Enable an alternate, more extensive memory test. 1567 1568- CFG_MEMTEST_SCRATCH: 1569 Scratch address used by the alternate memory test 1570 You only need to set this if address zero isn't writeable 1571 1572- CFG_TFTP_LOADADDR: 1573 Default load address for network file downloads 1574 1575- CFG_LOADS_BAUD_CHANGE: 1576 Enable temporary baudrate change while serial download 1577 1578- CFG_SDRAM_BASE: 1579 Physical start address of SDRAM. _Must_ be 0 here. 1580 1581- CFG_MBIO_BASE: 1582 Physical start address of Motherboard I/O (if using a 1583 Cogent motherboard) 1584 1585- CFG_FLASH_BASE: 1586 Physical start address of Flash memory. 1587 1588- CFG_MONITOR_BASE: 1589 Physical start address of boot monitor code (set by 1590 make config files to be same as the text base address 1591 (TEXT_BASE) used when linking) - same as 1592 CFG_FLASH_BASE when booting from flash. 1593 1594- CFG_MONITOR_LEN: 1595 Size of memory reserved for monitor code, used to 1596 determine _at_compile_time_ (!) if the environment is 1597 embedded within the U-Boot image, or in a separate 1598 flash sector. 1599 1600- CFG_MALLOC_LEN: 1601 Size of DRAM reserved for malloc() use. 1602 1603- CFG_BOOTMAPSZ: 1604 Maximum size of memory mapped by the startup code of 1605 the Linux kernel; all data that must be processed by 1606 the Linux kernel (bd_info, boot arguments, eventually 1607 initrd image) must be put below this limit. 1608 1609- CFG_MAX_FLASH_BANKS: 1610 Max number of Flash memory banks 1611 1612- CFG_MAX_FLASH_SECT: 1613 Max number of sectors on a Flash chip 1614 1615- CFG_FLASH_ERASE_TOUT: 1616 Timeout for Flash erase operations (in ms) 1617 1618- CFG_FLASH_WRITE_TOUT: 1619 Timeout for Flash write operations (in ms) 1620 1621- CFG_FLASH_LOCK_TOUT 1622 Timeout for Flash set sector lock bit operation (in ms) 1623 1624- CFG_FLASH_UNLOCK_TOUT 1625 Timeout for Flash clear lock bits operation (in ms) 1626 1627- CFG_FLASH_PROTECTION 1628 If defined, hardware flash sectors protection is used 1629 instead of U-Boot software protection. 1630 1631- CFG_DIRECT_FLASH_TFTP: 1632 1633 Enable TFTP transfers directly to flash memory; 1634 without this option such a download has to be 1635 performed in two steps: (1) download to RAM, and (2) 1636 copy from RAM to flash. 1637 1638 The two-step approach is usually more reliable, since 1639 you can check if the download worked before you erase 1640 the flash, but in some situations (when sytem RAM is 1641 too limited to allow for a tempory copy of the 1642 downloaded image) this option may be very useful. 1643 1644- CFG_FLASH_CFI: 1645 Define if the flash driver uses extra elements in the 1646 common flash structure for storing flash geometry. 1647 1648- CFG_FLASH_CFI_DRIVER 1649 This option also enables the building of the cfi_flash driver 1650 in the drivers directory 1651 1652- CFG_RX_ETH_BUFFER: 1653 Defines the number of ethernet receive buffers. On some 1654 ethernet controllers it is recommended to set this value 1655 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1656 buffers can be full shortly after enabling the interface 1657 on high ethernet traffic. 1658 Defaults to 4 if not defined. 1659 1660The following definitions that deal with the placement and management 1661of environment data (variable area); in general, we support the 1662following configurations: 1663 1664- CFG_ENV_IS_IN_FLASH: 1665 1666 Define this if the environment is in flash memory. 1667 1668 a) The environment occupies one whole flash sector, which is 1669 "embedded" in the text segment with the U-Boot code. This 1670 happens usually with "bottom boot sector" or "top boot 1671 sector" type flash chips, which have several smaller 1672 sectors at the start or the end. For instance, such a 1673 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1674 such a case you would place the environment in one of the 1675 4 kB sectors - with U-Boot code before and after it. With 1676 "top boot sector" type flash chips, you would put the 1677 environment in one of the last sectors, leaving a gap 1678 between U-Boot and the environment. 1679 1680 - CFG_ENV_OFFSET: 1681 1682 Offset of environment data (variable area) to the 1683 beginning of flash memory; for instance, with bottom boot 1684 type flash chips the second sector can be used: the offset 1685 for this sector is given here. 1686 1687 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1688 1689 - CFG_ENV_ADDR: 1690 1691 This is just another way to specify the start address of 1692 the flash sector containing the environment (instead of 1693 CFG_ENV_OFFSET). 1694 1695 - CFG_ENV_SECT_SIZE: 1696 1697 Size of the sector containing the environment. 1698 1699 1700 b) Sometimes flash chips have few, equal sized, BIG sectors. 1701 In such a case you don't want to spend a whole sector for 1702 the environment. 1703 1704 - CFG_ENV_SIZE: 1705 1706 If you use this in combination with CFG_ENV_IS_IN_FLASH 1707 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1708 of this flash sector for the environment. This saves 1709 memory for the RAM copy of the environment. 1710 1711 It may also save flash memory if you decide to use this 1712 when your environment is "embedded" within U-Boot code, 1713 since then the remainder of the flash sector could be used 1714 for U-Boot code. It should be pointed out that this is 1715 STRONGLY DISCOURAGED from a robustness point of view: 1716 updating the environment in flash makes it always 1717 necessary to erase the WHOLE sector. If something goes 1718 wrong before the contents has been restored from a copy in 1719 RAM, your target system will be dead. 1720 1721 - CFG_ENV_ADDR_REDUND 1722 CFG_ENV_SIZE_REDUND 1723 1724 These settings describe a second storage area used to hold 1725 a redundand copy of the environment data, so that there is 1726 a valid backup copy in case there is a power failure during 1727 a "saveenv" operation. 1728 1729BE CAREFUL! Any changes to the flash layout, and some changes to the 1730source code will make it necessary to adapt <board>/u-boot.lds* 1731accordingly! 1732 1733 1734- CFG_ENV_IS_IN_NVRAM: 1735 1736 Define this if you have some non-volatile memory device 1737 (NVRAM, battery buffered SRAM) which you want to use for the 1738 environment. 1739 1740 - CFG_ENV_ADDR: 1741 - CFG_ENV_SIZE: 1742 1743 These two #defines are used to determin the memory area you 1744 want to use for environment. It is assumed that this memory 1745 can just be read and written to, without any special 1746 provision. 1747 1748BE CAREFUL! The first access to the environment happens quite early 1749in U-Boot initalization (when we try to get the setting of for the 1750console baudrate). You *MUST* have mappend your NVRAM area then, or 1751U-Boot will hang. 1752 1753Please note that even with NVRAM we still use a copy of the 1754environment in RAM: we could work on NVRAM directly, but we want to 1755keep settings there always unmodified except somebody uses "saveenv" 1756to save the current settings. 1757 1758 1759- CFG_ENV_IS_IN_EEPROM: 1760 1761 Use this if you have an EEPROM or similar serial access 1762 device and a driver for it. 1763 1764 - CFG_ENV_OFFSET: 1765 - CFG_ENV_SIZE: 1766 1767 These two #defines specify the offset and size of the 1768 environment area within the total memory of your EEPROM. 1769 1770 - CFG_I2C_EEPROM_ADDR: 1771 If defined, specified the chip address of the EEPROM device. 1772 The default address is zero. 1773 1774 - CFG_EEPROM_PAGE_WRITE_BITS: 1775 If defined, the number of bits used to address bytes in a 1776 single page in the EEPROM device. A 64 byte page, for example 1777 would require six bits. 1778 1779 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1780 If defined, the number of milliseconds to delay between 1781 page writes. The default is zero milliseconds. 1782 1783 - CFG_I2C_EEPROM_ADDR_LEN: 1784 The length in bytes of the EEPROM memory array address. Note 1785 that this is NOT the chip address length! 1786 1787 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 1788 EEPROM chips that implement "address overflow" are ones 1789 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 1790 address and the extra bits end up in the "chip address" bit 1791 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 1792 byte chips. 1793 1794 Note that we consider the length of the address field to 1795 still be one byte because the extra address bits are hidden 1796 in the chip address. 1797 1798 - CFG_EEPROM_SIZE: 1799 The size in bytes of the EEPROM device. 1800 1801 1802- CFG_ENV_IS_IN_DATAFLASH: 1803 1804 Define this if you have a DataFlash memory device which you 1805 want to use for the environment. 1806 1807 - CFG_ENV_OFFSET: 1808 - CFG_ENV_ADDR: 1809 - CFG_ENV_SIZE: 1810 1811 These three #defines specify the offset and size of the 1812 environment area within the total memory of your DataFlash placed 1813 at the specified address. 1814 1815 1816- CFG_SPI_INIT_OFFSET 1817 1818 Defines offset to the initial SPI buffer area in DPRAM. The 1819 area is used at an early stage (ROM part) if the environment 1820 is configured to reside in the SPI EEPROM: We need a 520 byte 1821 scratch DPRAM area. It is used between the two initialization 1822 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1823 to be a good choice since it makes it far enough from the 1824 start of the data area as well as from the stack pointer. 1825 1826Please note that the environment is read-only as long as the monitor 1827has been relocated to RAM and a RAM copy of the environment has been 1828created; also, when using EEPROM you will have to use getenv_r() 1829until then to read environment variables. 1830 1831The environment is protected by a CRC32 checksum. Before the monitor 1832is relocated into RAM, as a result of a bad CRC you will be working 1833with the compiled-in default environment - *silently*!!! [This is 1834necessary, because the first environment variable we need is the 1835"baudrate" setting for the console - if we have a bad CRC, we don't 1836have any device yet where we could complain.] 1837 1838Note: once the monitor has been relocated, then it will complain if 1839the default environment is used; a new CRC is computed as soon as you 1840use the "saveenv" command to store a valid environment. 1841 1842- CFG_FAULT_ECHO_LINK_DOWN: 1843 Echo the inverted Ethernet link state to the fault LED. 1844 1845 Note: If this option is active, then CFG_FAULT_MII_ADDR 1846 also needs to be defined. 1847 1848- CFG_FAULT_MII_ADDR: 1849 MII address of the PHY to check for the Ethernet link state. 1850 1851- CFG_64BIT_VSPRINTF: 1852 Makes vsprintf (and all *printf functions) support printing 1853 of 64bit values by using the L quantifier 1854 1855- CFG_64BIT_STRTOUL: 1856 Adds simple_strtoull that returns a 64bit value 1857 1858Low Level (hardware related) configuration options: 1859--------------------------------------------------- 1860 1861- CFG_CACHELINE_SIZE: 1862 Cache Line Size of the CPU. 1863 1864- CFG_DEFAULT_IMMR: 1865 Default address of the IMMR after system reset. 1866 1867 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1868 and RPXsuper) to be able to adjust the position of 1869 the IMMR register after a reset. 1870 1871- Floppy Disk Support: 1872 CFG_FDC_DRIVE_NUMBER 1873 1874 the default drive number (default value 0) 1875 1876 CFG_ISA_IO_STRIDE 1877 1878 defines the spacing between fdc chipset registers 1879 (default value 1) 1880 1881 CFG_ISA_IO_OFFSET 1882 1883 defines the offset of register from address. It 1884 depends on which part of the data bus is connected to 1885 the fdc chipset. (default value 0) 1886 1887 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1888 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1889 default value. 1890 1891 if CFG_FDC_HW_INIT is defined, then the function 1892 fdc_hw_init() is called at the beginning of the FDC 1893 setup. fdc_hw_init() must be provided by the board 1894 source code. It is used to make hardware dependant 1895 initializations. 1896 1897- CFG_IMMR: Physical address of the Internal Memory Mapped 1898 Register; DO NOT CHANGE! (11-4) 1899 [MPC8xx systems only] 1900 1901- CFG_INIT_RAM_ADDR: 1902 1903 Start address of memory area that can be used for 1904 initial data and stack; please note that this must be 1905 writable memory that is working WITHOUT special 1906 initialization, i. e. you CANNOT use normal RAM which 1907 will become available only after programming the 1908 memory controller and running certain initialization 1909 sequences. 1910 1911 U-Boot uses the following memory types: 1912 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1913 - MPC824X: data cache 1914 - PPC4xx: data cache 1915 1916- CFG_GBL_DATA_OFFSET: 1917 1918 Offset of the initial data structure in the memory 1919 area defined by CFG_INIT_RAM_ADDR. Usually 1920 CFG_GBL_DATA_OFFSET is chosen such that the initial 1921 data is located at the end of the available space 1922 (sometimes written as (CFG_INIT_RAM_END - 1923 CFG_INIT_DATA_SIZE), and the initial stack is just 1924 below that area (growing from (CFG_INIT_RAM_ADDR + 1925 CFG_GBL_DATA_OFFSET) downward. 1926 1927 Note: 1928 On the MPC824X (or other systems that use the data 1929 cache for initial memory) the address chosen for 1930 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1931 point to an otherwise UNUSED address space between 1932 the top of RAM and the start of the PCI space. 1933 1934- CFG_SIUMCR: SIU Module Configuration (11-6) 1935 1936- CFG_SYPCR: System Protection Control (11-9) 1937 1938- CFG_TBSCR: Time Base Status and Control (11-26) 1939 1940- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1941 1942- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1943 1944- CFG_SCCR: System Clock and reset Control Register (15-27) 1945 1946- CFG_OR_TIMING_SDRAM: 1947 SDRAM timing 1948 1949- CFG_MAMR_PTA: 1950 periodic timer for refresh 1951 1952- CFG_DER: Debug Event Register (37-47) 1953 1954- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1955 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1956 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1957 CFG_BR1_PRELIM: 1958 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1959 1960- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1961 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1962 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1963 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1964 1965- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1966 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1967 Machine Mode Register and Memory Periodic Timer 1968 Prescaler definitions (SDRAM timing) 1969 1970- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1971 enable I2C microcode relocation patch (MPC8xx); 1972 define relocation offset in DPRAM [DSP2] 1973 1974- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1975 enable SPI microcode relocation patch (MPC8xx); 1976 define relocation offset in DPRAM [SCC4] 1977 1978- CFG_USE_OSCCLK: 1979 Use OSCM clock mode on MBX8xx board. Be careful, 1980 wrong setting might damage your board. Read 1981 doc/README.MBX before setting this variable! 1982 1983- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1984 Offset of the bootmode word in DPRAM used by post 1985 (Power On Self Tests). This definition overrides 1986 #define'd default value in commproc.h resp. 1987 cpm_8260.h. 1988 1989- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 1990 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 1991 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 1992 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 1993 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 1994 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 1995 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 1996 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 1997 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 1998 1999- CONFIG_ETHER_ON_FEC[12] 2000 Define to enable FEC[12] on a 8xx series processor. 2001 2002- CONFIG_FEC[12]_PHY 2003 Define to the hardcoded PHY address which corresponds 2004 to the given FEC; i. e. 2005 #define CONFIG_FEC1_PHY 4 2006 means that the PHY with address 4 is connected to FEC1 2007 2008 When set to -1, means to probe for first available. 2009 2010- CONFIG_FEC[12]_PHY_NORXERR 2011 The PHY does not have a RXERR line (RMII only). 2012 (so program the FEC to ignore it). 2013 2014- CONFIG_RMII 2015 Enable RMII mode for all FECs. 2016 Note that this is a global option, we can't 2017 have one FEC in standard MII mode and another in RMII mode. 2018 2019- CONFIG_CRC32_VERIFY 2020 Add a verify option to the crc32 command. 2021 The syntax is: 2022 2023 => crc32 -v <address> <count> <crc32> 2024 2025 Where address/count indicate a memory area 2026 and crc32 is the correct crc32 which the 2027 area should have. 2028 2029Building the Software: 2030====================== 2031 2032Building U-Boot has been tested in native PPC environments (on a 2033PowerBook G3 running LinuxPPC 2000) and in cross environments 2034(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2035NetBSD 1.5 on x86). 2036 2037If you are not using a native PPC environment, it is assumed that you 2038have the GNU cross compiling tools available in your path and named 2039with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2040you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2041the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2042change it to: 2043 2044 CROSS_COMPILE = ppc_4xx- 2045 2046 2047U-Boot is intended to be simple to build. After installing the 2048sources you must configure U-Boot for one specific board type. This 2049is done by typing: 2050 2051 make NAME_config 2052 2053where "NAME_config" is the name of one of the existing 2054configurations; the following names are supported: 2055 2056 ADCIOP_config FPS850L_config omap1610inn_config 2057 ADS860_config FPS860L_config pcu_e_config 2058 AR405_config GEN860T_config PIP405_config 2059 at91rm9200dk_config GENIETV_config QS823_config 2060 CANBT_config GTH_config QS850_config 2061 cmi_mpc5xx_config hermes_config QS860T_config 2062 cogent_common_config hymod_config RPXlite_config 2063 cogent_mpc8260_config IP860_config RPXsuper_config 2064 cogent_mpc8xx_config IVML24_config rsdproto_config 2065 CPCI405_config IVMS8_config Sandpoint8240_config 2066 CPCIISER4_config JSE_config sbc8260_config 2067 csb272_config LANTEC_config SM850_config 2068 CU824_config lwmon_config SPD823TS_config 2069 DUET_ADS_config MBX860T_config stxgp3_config 2070 EBONY_config MBX_config SXNI855T_config 2071 ELPT860_config MPC8260ADS_config TQM823L_config 2072 ESTEEM192E_config MPC8540ADS_config TQM850L_config 2073 ETX094_config MPC8560ADS_config TQM855L_config 2074 FADS823_config NETVIA_config TQM860L_config 2075 FADS850SAR_config omap1510inn_config WALNUT405_config 2076 FADS860T_config omap1610h2_config ZPC1900_config 2077 2078Note: for some board special configuration names may exist; check if 2079 additional information is available from the board vendor; for 2080 instance, the TQM823L systems are available without (standard) 2081 or with LCD support. You can select such additional "features" 2082 when chosing the configuration, i. e. 2083 2084 make TQM823L_config 2085 - will configure for a plain TQM823L, i. e. no LCD support 2086 2087 make TQM823L_LCD_config 2088 - will configure for a TQM823L with U-Boot console on LCD 2089 2090 etc. 2091 2092 2093Finally, type "make all", and you should get some working U-Boot 2094images ready for download to / installation on your system: 2095 2096- "u-boot.bin" is a raw binary image 2097- "u-boot" is an image in ELF binary format 2098- "u-boot.srec" is in Motorola S-Record format 2099 2100 2101Please be aware that the Makefiles assume you are using GNU make, so 2102for instance on NetBSD you might need to use "gmake" instead of 2103native "make". 2104 2105 2106If the system board that you have is not listed, then you will need 2107to port U-Boot to your hardware platform. To do this, follow these 2108steps: 2109 21101. Add a new configuration option for your board to the toplevel 2111 "Makefile" and to the "MAKEALL" script, using the existing 2112 entries as examples. Note that here and at many other places 2113 boards and other names are listed in alphabetical sort order. Please 2114 keep this order. 21152. Create a new directory to hold your board specific code. Add any 2116 files you need. In your board directory, you will need at least 2117 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 21183. Create a new configuration file "include/configs/<board>.h" for 2119 your board 21203. If you're porting U-Boot to a new CPU, then also create a new 2121 directory to hold your CPU specific code. Add any files you need. 21224. Run "make <board>_config" with your new name. 21235. Type "make", and you should get a working "u-boot.srec" file 2124 to be installed on your target system. 21256. Debug and solve any problems that might arise. 2126 [Of course, this last step is much harder than it sounds.] 2127 2128 2129Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2130============================================================== 2131 2132If you have modified U-Boot sources (for instance added a new board 2133or support for new devices, a new CPU, etc.) you are expected to 2134provide feedback to the other developers. The feedback normally takes 2135the form of a "patch", i. e. a context diff against a certain (latest 2136official or latest in CVS) version of U-Boot sources. 2137 2138But before you submit such a patch, please verify that your modifi- 2139cation did not break existing code. At least make sure that *ALL* of 2140the supported boards compile WITHOUT ANY compiler warnings. To do so, 2141just run the "MAKEALL" script, which will configure and build U-Boot 2142for ALL supported system. Be warned, this will take a while. You can 2143select which (cross) compiler to use by passing a `CROSS_COMPILE' 2144environment variable to the script, i. e. to use the cross tools from 2145MontaVista's Hard Hat Linux you can type 2146 2147 CROSS_COMPILE=ppc_8xx- MAKEALL 2148 2149or to build on a native PowerPC system you can type 2150 2151 CROSS_COMPILE=' ' MAKEALL 2152 2153See also "U-Boot Porting Guide" below. 2154 2155 2156Monitor Commands - Overview: 2157============================ 2158 2159go - start application at address 'addr' 2160run - run commands in an environment variable 2161bootm - boot application image from memory 2162bootp - boot image via network using BootP/TFTP protocol 2163tftpboot- boot image via network using TFTP protocol 2164 and env variables "ipaddr" and "serverip" 2165 (and eventually "gatewayip") 2166rarpboot- boot image via network using RARP/TFTP protocol 2167diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2168loads - load S-Record file over serial line 2169loadb - load binary file over serial line (kermit mode) 2170md - memory display 2171mm - memory modify (auto-incrementing) 2172nm - memory modify (constant address) 2173mw - memory write (fill) 2174cp - memory copy 2175cmp - memory compare 2176crc32 - checksum calculation 2177imd - i2c memory display 2178imm - i2c memory modify (auto-incrementing) 2179inm - i2c memory modify (constant address) 2180imw - i2c memory write (fill) 2181icrc32 - i2c checksum calculation 2182iprobe - probe to discover valid I2C chip addresses 2183iloop - infinite loop on address range 2184isdram - print SDRAM configuration information 2185sspi - SPI utility commands 2186base - print or set address offset 2187printenv- print environment variables 2188setenv - set environment variables 2189saveenv - save environment variables to persistent storage 2190protect - enable or disable FLASH write protection 2191erase - erase FLASH memory 2192flinfo - print FLASH memory information 2193bdinfo - print Board Info structure 2194iminfo - print header information for application image 2195coninfo - print console devices and informations 2196ide - IDE sub-system 2197loop - infinite loop on address range 2198mtest - simple RAM test 2199icache - enable or disable instruction cache 2200dcache - enable or disable data cache 2201reset - Perform RESET of the CPU 2202echo - echo args to console 2203version - print monitor version 2204help - print online help 2205? - alias for 'help' 2206 2207 2208Monitor Commands - Detailed Description: 2209======================================== 2210 2211TODO. 2212 2213For now: just type "help <command>". 2214 2215 2216Environment Variables: 2217====================== 2218 2219U-Boot supports user configuration using Environment Variables which 2220can be made persistent by saving to Flash memory. 2221 2222Environment Variables are set using "setenv", printed using 2223"printenv", and saved to Flash using "saveenv". Using "setenv" 2224without a value can be used to delete a variable from the 2225environment. As long as you don't save the environment you are 2226working with an in-memory copy. In case the Flash area containing the 2227environment is erased by accident, a default environment is provided. 2228 2229Some configuration options can be set using Environment Variables: 2230 2231 baudrate - see CONFIG_BAUDRATE 2232 2233 bootdelay - see CONFIG_BOOTDELAY 2234 2235 bootcmd - see CONFIG_BOOTCOMMAND 2236 2237 bootargs - Boot arguments when booting an RTOS image 2238 2239 bootfile - Name of the image to load with TFTP 2240 2241 autoload - if set to "no" (any string beginning with 'n'), 2242 "bootp" will just load perform a lookup of the 2243 configuration from the BOOTP server, but not try to 2244 load any image using TFTP 2245 2246 autostart - if set to "yes", an image loaded using the "bootp", 2247 "rarpboot", "tftpboot" or "diskboot" commands will 2248 be automatically started (by internally calling 2249 "bootm") 2250 2251 If set to "no", a standalone image passed to the 2252 "bootm" command will be copied to the load address 2253 (and eventually uncompressed), but NOT be started. 2254 This can be used to load and uncompress arbitrary 2255 data. 2256 2257 i2cfast - (PPC405GP|PPC405EP only) 2258 if set to 'y' configures Linux I2C driver for fast 2259 mode (400kHZ). This environment variable is used in 2260 initialization code. So, for changes to be effective 2261 it must be saved and board must be reset. 2262 2263 initrd_high - restrict positioning of initrd images: 2264 If this variable is not set, initrd images will be 2265 copied to the highest possible address in RAM; this 2266 is usually what you want since it allows for 2267 maximum initrd size. If for some reason you want to 2268 make sure that the initrd image is loaded below the 2269 CFG_BOOTMAPSZ limit, you can set this environment 2270 variable to a value of "no" or "off" or "0". 2271 Alternatively, you can set it to a maximum upper 2272 address to use (U-Boot will still check that it 2273 does not overwrite the U-Boot stack and data). 2274 2275 For instance, when you have a system with 16 MB 2276 RAM, and want to reserve 4 MB from use by Linux, 2277 you can do this by adding "mem=12M" to the value of 2278 the "bootargs" variable. However, now you must make 2279 sure that the initrd image is placed in the first 2280 12 MB as well - this can be done with 2281 2282 setenv initrd_high 00c00000 2283 2284 If you set initrd_high to 0xFFFFFFFF, this is an 2285 indication to U-Boot that all addresses are legal 2286 for the Linux kernel, including addresses in flash 2287 memory. In this case U-Boot will NOT COPY the 2288 ramdisk at all. This may be useful to reduce the 2289 boot time on your system, but requires that this 2290 feature is supported by your Linux kernel. 2291 2292 ipaddr - IP address; needed for tftpboot command 2293 2294 loadaddr - Default load address for commands like "bootp", 2295 "rarpboot", "tftpboot", "loadb" or "diskboot" 2296 2297 loads_echo - see CONFIG_LOADS_ECHO 2298 2299 serverip - TFTP server IP address; needed for tftpboot command 2300 2301 bootretry - see CONFIG_BOOT_RETRY_TIME 2302 2303 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2304 2305 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2306 2307 ethprime - When CONFIG_NET_MULTI is enabled controls which 2308 interface is used first. 2309 2310 ethact - When CONFIG_NET_MULTI is enabled controls which 2311 interface is currently active. For example you 2312 can do the following 2313 2314 => setenv ethact FEC ETHERNET 2315 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2316 => setenv ethact SCC ETHERNET 2317 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2318 2319 netretry - When set to "no" each network operation will 2320 either succeed or fail without retrying. 2321 When set to "once" the network operation will 2322 fail when all the available network interfaces 2323 are tried once without success. 2324 Useful on scripts which control the retry operation 2325 themselves. 2326 2327 vlan - When set to a value < 4095 the traffic over 2328 ethernet is encapsulated/received over 802.1q 2329 VLAN tagged frames. 2330 2331The following environment variables may be used and automatically 2332updated by the network boot commands ("bootp" and "rarpboot"), 2333depending the information provided by your boot server: 2334 2335 bootfile - see above 2336 dnsip - IP address of your Domain Name Server 2337 dnsip2 - IP address of your secondary Domain Name Server 2338 gatewayip - IP address of the Gateway (Router) to use 2339 hostname - Target hostname 2340 ipaddr - see above 2341 netmask - Subnet Mask 2342 rootpath - Pathname of the root filesystem on the NFS server 2343 serverip - see above 2344 2345 2346There are two special Environment Variables: 2347 2348 serial# - contains hardware identification information such 2349 as type string and/or serial number 2350 ethaddr - Ethernet address 2351 2352These variables can be set only once (usually during manufacturing of 2353the board). U-Boot refuses to delete or overwrite these variables 2354once they have been set once. 2355 2356 2357Further special Environment Variables: 2358 2359 ver - Contains the U-Boot version string as printed 2360 with the "version" command. This variable is 2361 readonly (see CONFIG_VERSION_VARIABLE). 2362 2363 2364Please note that changes to some configuration parameters may take 2365only effect after the next boot (yes, that's just like Windoze :-). 2366 2367 2368Command Line Parsing: 2369===================== 2370 2371There are two different command line parsers available with U-Boot: 2372the old "simple" one, and the much more powerful "hush" shell: 2373 2374Old, simple command line parser: 2375-------------------------------- 2376 2377- supports environment variables (through setenv / saveenv commands) 2378- several commands on one line, separated by ';' 2379- variable substitution using "... $(name) ..." syntax 2380- special characters ('$', ';') can be escaped by prefixing with '\', 2381 for example: 2382 setenv bootcmd bootm \$(address) 2383- You can also escape text by enclosing in single apostrophes, for example: 2384 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2385 2386Hush shell: 2387----------- 2388 2389- similar to Bourne shell, with control structures like 2390 if...then...else...fi, for...do...done; while...do...done, 2391 until...do...done, ... 2392- supports environment ("global") variables (through setenv / saveenv 2393 commands) and local shell variables (through standard shell syntax 2394 "name=value"); only environment variables can be used with "run" 2395 command 2396 2397General rules: 2398-------------- 2399 2400(1) If a command line (or an environment variable executed by a "run" 2401 command) contains several commands separated by semicolon, and 2402 one of these commands fails, then the remaining commands will be 2403 executed anyway. 2404 2405(2) If you execute several variables with one call to run (i. e. 2406 calling run with a list af variables as arguments), any failing 2407 command will cause "run" to terminate, i. e. the remaining 2408 variables are not executed. 2409 2410Note for Redundant Ethernet Interfaces: 2411======================================= 2412 2413Some boards come with redundant ethernet interfaces; U-Boot supports 2414such configurations and is capable of automatic selection of a 2415"working" interface when needed. MAC assignment works as follows: 2416 2417Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2418MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2419"eth1addr" (=>eth1), "eth2addr", ... 2420 2421If the network interface stores some valid MAC address (for instance 2422in SROM), this is used as default address if there is NO correspon- 2423ding setting in the environment; if the corresponding environment 2424variable is set, this overrides the settings in the card; that means: 2425 2426o If the SROM has a valid MAC address, and there is no address in the 2427 environment, the SROM's address is used. 2428 2429o If there is no valid address in the SROM, and a definition in the 2430 environment exists, then the value from the environment variable is 2431 used. 2432 2433o If both the SROM and the environment contain a MAC address, and 2434 both addresses are the same, this MAC address is used. 2435 2436o If both the SROM and the environment contain a MAC address, and the 2437 addresses differ, the value from the environment is used and a 2438 warning is printed. 2439 2440o If neither SROM nor the environment contain a MAC address, an error 2441 is raised. 2442 2443 2444Image Formats: 2445============== 2446 2447The "boot" commands of this monitor operate on "image" files which 2448can be basicly anything, preceeded by a special header; see the 2449definitions in include/image.h for details; basicly, the header 2450defines the following image properties: 2451 2452* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2453 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2454 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2455 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2456* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2457 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2458 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC). 2459* Compression Type (uncompressed, gzip, bzip2) 2460* Load Address 2461* Entry Point 2462* Image Name 2463* Image Timestamp 2464 2465The header is marked by a special Magic Number, and both the header 2466and the data portions of the image are secured against corruption by 2467CRC32 checksums. 2468 2469 2470Linux Support: 2471============== 2472 2473Although U-Boot should support any OS or standalone application 2474easily, the main focus has always been on Linux during the design of 2475U-Boot. 2476 2477U-Boot includes many features that so far have been part of some 2478special "boot loader" code within the Linux kernel. Also, any 2479"initrd" images to be used are no longer part of one big Linux image; 2480instead, kernel and "initrd" are separate images. This implementation 2481serves several purposes: 2482 2483- the same features can be used for other OS or standalone 2484 applications (for instance: using compressed images to reduce the 2485 Flash memory footprint) 2486 2487- it becomes much easier to port new Linux kernel versions because 2488 lots of low-level, hardware dependent stuff are done by U-Boot 2489 2490- the same Linux kernel image can now be used with different "initrd" 2491 images; of course this also means that different kernel images can 2492 be run with the same "initrd". This makes testing easier (you don't 2493 have to build a new "zImage.initrd" Linux image when you just 2494 change a file in your "initrd"). Also, a field-upgrade of the 2495 software is easier now. 2496 2497 2498Linux HOWTO: 2499============ 2500 2501Porting Linux to U-Boot based systems: 2502--------------------------------------- 2503 2504U-Boot cannot save you from doing all the necessary modifications to 2505configure the Linux device drivers for use with your target hardware 2506(no, we don't intend to provide a full virtual machine interface to 2507Linux :-). 2508 2509But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2510 2511Just make sure your machine specific header file (for instance 2512include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2513Information structure as we define in include/u-boot.h, and make 2514sure that your definition of IMAP_ADDR uses the same value as your 2515U-Boot configuration in CFG_IMMR. 2516 2517 2518Configuring the Linux kernel: 2519----------------------------- 2520 2521No specific requirements for U-Boot. Make sure you have some root 2522device (initial ramdisk, NFS) for your target system. 2523 2524 2525Building a Linux Image: 2526----------------------- 2527 2528With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2529not used. If you use recent kernel source, a new build target 2530"uImage" will exist which automatically builds an image usable by 2531U-Boot. Most older kernels also have support for a "pImage" target, 2532which was introduced for our predecessor project PPCBoot and uses a 2533100% compatible format. 2534 2535Example: 2536 2537 make TQM850L_config 2538 make oldconfig 2539 make dep 2540 make uImage 2541 2542The "uImage" build target uses a special tool (in 'tools/mkimage') to 2543encapsulate a compressed Linux kernel image with header information, 2544CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2545 2546* build a standard "vmlinux" kernel image (in ELF binary format): 2547 2548* convert the kernel into a raw binary image: 2549 2550 ${CROSS_COMPILE}-objcopy -O binary \ 2551 -R .note -R .comment \ 2552 -S vmlinux linux.bin 2553 2554* compress the binary image: 2555 2556 gzip -9 linux.bin 2557 2558* package compressed binary image for U-Boot: 2559 2560 mkimage -A ppc -O linux -T kernel -C gzip \ 2561 -a 0 -e 0 -n "Linux Kernel Image" \ 2562 -d linux.bin.gz uImage 2563 2564 2565The "mkimage" tool can also be used to create ramdisk images for use 2566with U-Boot, either separated from the Linux kernel image, or 2567combined into one file. "mkimage" encapsulates the images with a 64 2568byte header containing information about target architecture, 2569operating system, image type, compression method, entry points, time 2570stamp, CRC32 checksums, etc. 2571 2572"mkimage" can be called in two ways: to verify existing images and 2573print the header information, or to build new images. 2574 2575In the first form (with "-l" option) mkimage lists the information 2576contained in the header of an existing U-Boot image; this includes 2577checksum verification: 2578 2579 tools/mkimage -l image 2580 -l ==> list image header information 2581 2582The second form (with "-d" option) is used to build a U-Boot image 2583from a "data file" which is used as image payload: 2584 2585 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2586 -n name -d data_file image 2587 -A ==> set architecture to 'arch' 2588 -O ==> set operating system to 'os' 2589 -T ==> set image type to 'type' 2590 -C ==> set compression type 'comp' 2591 -a ==> set load address to 'addr' (hex) 2592 -e ==> set entry point to 'ep' (hex) 2593 -n ==> set image name to 'name' 2594 -d ==> use image data from 'datafile' 2595 2596Right now, all Linux kernels for PowerPC systems use the same load 2597address (0x00000000), but the entry point address depends on the 2598kernel version: 2599 2600- 2.2.x kernels have the entry point at 0x0000000C, 2601- 2.3.x and later kernels have the entry point at 0x00000000. 2602 2603So a typical call to build a U-Boot image would read: 2604 2605 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2606 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2607 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2608 > examples/uImage.TQM850L 2609 Image Name: 2.4.4 kernel for TQM850L 2610 Created: Wed Jul 19 02:34:59 2000 2611 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2612 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2613 Load Address: 0x00000000 2614 Entry Point: 0x00000000 2615 2616To verify the contents of the image (or check for corruption): 2617 2618 -> tools/mkimage -l examples/uImage.TQM850L 2619 Image Name: 2.4.4 kernel for TQM850L 2620 Created: Wed Jul 19 02:34:59 2000 2621 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2622 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2623 Load Address: 0x00000000 2624 Entry Point: 0x00000000 2625 2626NOTE: for embedded systems where boot time is critical you can trade 2627speed for memory and install an UNCOMPRESSED image instead: this 2628needs more space in Flash, but boots much faster since it does not 2629need to be uncompressed: 2630 2631 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2632 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2633 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2634 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2635 > examples/uImage.TQM850L-uncompressed 2636 Image Name: 2.4.4 kernel for TQM850L 2637 Created: Wed Jul 19 02:34:59 2000 2638 Image Type: PowerPC Linux Kernel Image (uncompressed) 2639 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2640 Load Address: 0x00000000 2641 Entry Point: 0x00000000 2642 2643 2644Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2645when your kernel is intended to use an initial ramdisk: 2646 2647 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2648 > -A ppc -O linux -T ramdisk -C gzip \ 2649 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2650 Image Name: Simple Ramdisk Image 2651 Created: Wed Jan 12 14:01:50 2000 2652 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2653 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2654 Load Address: 0x00000000 2655 Entry Point: 0x00000000 2656 2657 2658Installing a Linux Image: 2659------------------------- 2660 2661To downloading a U-Boot image over the serial (console) interface, 2662you must convert the image to S-Record format: 2663 2664 objcopy -I binary -O srec examples/image examples/image.srec 2665 2666The 'objcopy' does not understand the information in the U-Boot 2667image header, so the resulting S-Record file will be relative to 2668address 0x00000000. To load it to a given address, you need to 2669specify the target address as 'offset' parameter with the 'loads' 2670command. 2671 2672Example: install the image to address 0x40100000 (which on the 2673TQM8xxL is in the first Flash bank): 2674 2675 => erase 40100000 401FFFFF 2676 2677 .......... done 2678 Erased 8 sectors 2679 2680 => loads 40100000 2681 ## Ready for S-Record download ... 2682 ~>examples/image.srec 2683 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2684 ... 2685 15989 15990 15991 15992 2686 [file transfer complete] 2687 [connected] 2688 ## Start Addr = 0x00000000 2689 2690 2691You can check the success of the download using the 'iminfo' command; 2692this includes a checksum verification so you can be sure no data 2693corruption happened: 2694 2695 => imi 40100000 2696 2697 ## Checking Image at 40100000 ... 2698 Image Name: 2.2.13 for initrd on TQM850L 2699 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2700 Data Size: 335725 Bytes = 327 kB = 0 MB 2701 Load Address: 00000000 2702 Entry Point: 0000000c 2703 Verifying Checksum ... OK 2704 2705 2706Boot Linux: 2707----------- 2708 2709The "bootm" command is used to boot an application that is stored in 2710memory (RAM or Flash). In case of a Linux kernel image, the contents 2711of the "bootargs" environment variable is passed to the kernel as 2712parameters. You can check and modify this variable using the 2713"printenv" and "setenv" commands: 2714 2715 2716 => printenv bootargs 2717 bootargs=root=/dev/ram 2718 2719 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2720 2721 => printenv bootargs 2722 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2723 2724 => bootm 40020000 2725 ## Booting Linux kernel at 40020000 ... 2726 Image Name: 2.2.13 for NFS on TQM850L 2727 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2728 Data Size: 381681 Bytes = 372 kB = 0 MB 2729 Load Address: 00000000 2730 Entry Point: 0000000c 2731 Verifying Checksum ... OK 2732 Uncompressing Kernel Image ... OK 2733 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 2734 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2735 time_init: decrementer frequency = 187500000/60 2736 Calibrating delay loop... 49.77 BogoMIPS 2737 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2738 ... 2739 2740If you want to boot a Linux kernel with initial ram disk, you pass 2741the memory addresses of both the kernel and the initrd image (PPBCOOT 2742format!) to the "bootm" command: 2743 2744 => imi 40100000 40200000 2745 2746 ## Checking Image at 40100000 ... 2747 Image Name: 2.2.13 for initrd on TQM850L 2748 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2749 Data Size: 335725 Bytes = 327 kB = 0 MB 2750 Load Address: 00000000 2751 Entry Point: 0000000c 2752 Verifying Checksum ... OK 2753 2754 ## Checking Image at 40200000 ... 2755 Image Name: Simple Ramdisk Image 2756 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2757 Data Size: 566530 Bytes = 553 kB = 0 MB 2758 Load Address: 00000000 2759 Entry Point: 00000000 2760 Verifying Checksum ... OK 2761 2762 => bootm 40100000 40200000 2763 ## Booting Linux kernel at 40100000 ... 2764 Image Name: 2.2.13 for initrd on TQM850L 2765 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2766 Data Size: 335725 Bytes = 327 kB = 0 MB 2767 Load Address: 00000000 2768 Entry Point: 0000000c 2769 Verifying Checksum ... OK 2770 Uncompressing Kernel Image ... OK 2771 ## Loading RAMDisk Image at 40200000 ... 2772 Image Name: Simple Ramdisk Image 2773 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2774 Data Size: 566530 Bytes = 553 kB = 0 MB 2775 Load Address: 00000000 2776 Entry Point: 00000000 2777 Verifying Checksum ... OK 2778 Loading Ramdisk ... OK 2779 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 2780 Boot arguments: root=/dev/ram 2781 time_init: decrementer frequency = 187500000/60 2782 Calibrating delay loop... 49.77 BogoMIPS 2783 ... 2784 RAMDISK: Compressed image found at block 0 2785 VFS: Mounted root (ext2 filesystem). 2786 2787 bash# 2788 2789More About U-Boot Image Types: 2790------------------------------ 2791 2792U-Boot supports the following image types: 2793 2794 "Standalone Programs" are directly runnable in the environment 2795 provided by U-Boot; it is expected that (if they behave 2796 well) you can continue to work in U-Boot after return from 2797 the Standalone Program. 2798 "OS Kernel Images" are usually images of some Embedded OS which 2799 will take over control completely. Usually these programs 2800 will install their own set of exception handlers, device 2801 drivers, set up the MMU, etc. - this means, that you cannot 2802 expect to re-enter U-Boot except by resetting the CPU. 2803 "RAMDisk Images" are more or less just data blocks, and their 2804 parameters (address, size) are passed to an OS kernel that is 2805 being started. 2806 "Multi-File Images" contain several images, typically an OS 2807 (Linux) kernel image and one or more data images like 2808 RAMDisks. This construct is useful for instance when you want 2809 to boot over the network using BOOTP etc., where the boot 2810 server provides just a single image file, but you want to get 2811 for instance an OS kernel and a RAMDisk image. 2812 2813 "Multi-File Images" start with a list of image sizes, each 2814 image size (in bytes) specified by an "uint32_t" in network 2815 byte order. This list is terminated by an "(uint32_t)0". 2816 Immediately after the terminating 0 follow the images, one by 2817 one, all aligned on "uint32_t" boundaries (size rounded up to 2818 a multiple of 4 bytes). 2819 2820 "Firmware Images" are binary images containing firmware (like 2821 U-Boot or FPGA images) which usually will be programmed to 2822 flash memory. 2823 2824 "Script files" are command sequences that will be executed by 2825 U-Boot's command interpreter; this feature is especially 2826 useful when you configure U-Boot to use a real shell (hush) 2827 as command interpreter. 2828 2829 2830Standalone HOWTO: 2831================= 2832 2833One of the features of U-Boot is that you can dynamically load and 2834run "standalone" applications, which can use some resources of 2835U-Boot like console I/O functions or interrupt services. 2836 2837Two simple examples are included with the sources: 2838 2839"Hello World" Demo: 2840------------------- 2841 2842'examples/hello_world.c' contains a small "Hello World" Demo 2843application; it is automatically compiled when you build U-Boot. 2844It's configured to run at address 0x00040004, so you can play with it 2845like that: 2846 2847 => loads 2848 ## Ready for S-Record download ... 2849 ~>examples/hello_world.srec 2850 1 2 3 4 5 6 7 8 9 10 11 ... 2851 [file transfer complete] 2852 [connected] 2853 ## Start Addr = 0x00040004 2854 2855 => go 40004 Hello World! This is a test. 2856 ## Starting application at 0x00040004 ... 2857 Hello World 2858 argc = 7 2859 argv[0] = "40004" 2860 argv[1] = "Hello" 2861 argv[2] = "World!" 2862 argv[3] = "This" 2863 argv[4] = "is" 2864 argv[5] = "a" 2865 argv[6] = "test." 2866 argv[7] = "<NULL>" 2867 Hit any key to exit ... 2868 2869 ## Application terminated, rc = 0x0 2870 2871Another example, which demonstrates how to register a CPM interrupt 2872handler with the U-Boot code, can be found in 'examples/timer.c'. 2873Here, a CPM timer is set up to generate an interrupt every second. 2874The interrupt service routine is trivial, just printing a '.' 2875character, but this is just a demo program. The application can be 2876controlled by the following keys: 2877 2878 ? - print current values og the CPM Timer registers 2879 b - enable interrupts and start timer 2880 e - stop timer and disable interrupts 2881 q - quit application 2882 2883 => loads 2884 ## Ready for S-Record download ... 2885 ~>examples/timer.srec 2886 1 2 3 4 5 6 7 8 9 10 11 ... 2887 [file transfer complete] 2888 [connected] 2889 ## Start Addr = 0x00040004 2890 2891 => go 40004 2892 ## Starting application at 0x00040004 ... 2893 TIMERS=0xfff00980 2894 Using timer 1 2895 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2896 2897Hit 'b': 2898 [q, b, e, ?] Set interval 1000000 us 2899 Enabling timer 2900Hit '?': 2901 [q, b, e, ?] ........ 2902 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2903Hit '?': 2904 [q, b, e, ?] . 2905 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2906Hit '?': 2907 [q, b, e, ?] . 2908 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2909Hit '?': 2910 [q, b, e, ?] . 2911 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2912Hit 'e': 2913 [q, b, e, ?] ...Stopping timer 2914Hit 'q': 2915 [q, b, e, ?] ## Application terminated, rc = 0x0 2916 2917 2918Minicom warning: 2919================ 2920 2921Over time, many people have reported problems when trying to use the 2922"minicom" terminal emulation program for serial download. I (wd) 2923consider minicom to be broken, and recommend not to use it. Under 2924Unix, I recommend to use C-Kermit for general purpose use (and 2925especially for kermit binary protocol download ("loadb" command), and 2926use "cu" for S-Record download ("loads" command). 2927 2928Nevertheless, if you absolutely want to use it try adding this 2929configuration to your "File transfer protocols" section: 2930 2931 Name Program Name U/D FullScr IO-Red. Multi 2932 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2933 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2934 2935 2936NetBSD Notes: 2937============= 2938 2939Starting at version 0.9.2, U-Boot supports NetBSD both as host 2940(build U-Boot) and target system (boots NetBSD/mpc8xx). 2941 2942Building requires a cross environment; it is known to work on 2943NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2944need gmake since the Makefiles are not compatible with BSD make). 2945Note that the cross-powerpc package does not install include files; 2946attempting to build U-Boot will fail because <machine/ansi.h> is 2947missing. This file has to be installed and patched manually: 2948 2949 # cd /usr/pkg/cross/powerpc-netbsd/include 2950 # mkdir powerpc 2951 # ln -s powerpc machine 2952 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2953 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2954 2955Native builds *don't* work due to incompatibilities between native 2956and U-Boot include files. 2957 2958Booting assumes that (the first part of) the image booted is a 2959stage-2 loader which in turn loads and then invokes the kernel 2960proper. Loader sources will eventually appear in the NetBSD source 2961tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2962meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2963details. 2964 2965 2966Implementation Internals: 2967========================= 2968 2969The following is not intended to be a complete description of every 2970implementation detail. However, it should help to understand the 2971inner workings of U-Boot and make it easier to port it to custom 2972hardware. 2973 2974 2975Initial Stack, Global Data: 2976--------------------------- 2977 2978The implementation of U-Boot is complicated by the fact that U-Boot 2979starts running out of ROM (flash memory), usually without access to 2980system RAM (because the memory controller is not initialized yet). 2981This means that we don't have writable Data or BSS segments, and BSS 2982is not initialized as zero. To be able to get a C environment working 2983at all, we have to allocate at least a minimal stack. Implementation 2984options for this are defined and restricted by the CPU used: Some CPU 2985models provide on-chip memory (like the IMMR area on MPC8xx and 2986MPC826x processors), on others (parts of) the data cache can be 2987locked as (mis-) used as memory, etc. 2988 2989 Chris Hallinan posted a good summary of these issues to the 2990 u-boot-users mailing list: 2991 2992 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 2993 From: "Chris Hallinan" <clh@net1plus.com> 2994 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 2995 ... 2996 2997 Correct me if I'm wrong, folks, but the way I understand it 2998 is this: Using DCACHE as initial RAM for Stack, etc, does not 2999 require any physical RAM backing up the cache. The cleverness 3000 is that the cache is being used as a temporary supply of 3001 necessary storage before the SDRAM controller is setup. It's 3002 beyond the scope of this list to expain the details, but you 3003 can see how this works by studying the cache architecture and 3004 operation in the architecture and processor-specific manuals. 3005 3006 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3007 is another option for the system designer to use as an 3008 initial stack/ram area prior to SDRAM being available. Either 3009 option should work for you. Using CS 4 should be fine if your 3010 board designers haven't used it for something that would 3011 cause you grief during the initial boot! It is frequently not 3012 used. 3013 3014 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3015 with your processor/board/system design. The default value 3016 you will find in any recent u-boot distribution in 3017 Walnut405.h should work for you. I'd set it to a value larger 3018 than your SDRAM module. If you have a 64MB SDRAM module, set 3019 it above 400_0000. Just make sure your board has no resources 3020 that are supposed to respond to that address! That code in 3021 start.S has been around a while and should work as is when 3022 you get the config right. 3023 3024 -Chris Hallinan 3025 DS4.COM, Inc. 3026 3027It is essential to remember this, since it has some impact on the C 3028code for the initialization procedures: 3029 3030* Initialized global data (data segment) is read-only. Do not attempt 3031 to write it. 3032 3033* Do not use any unitialized global data (or implicitely initialized 3034 as zero data - BSS segment) at all - this is undefined, initiali- 3035 zation is performed later (when relocating to RAM). 3036 3037* Stack space is very limited. Avoid big data buffers or things like 3038 that. 3039 3040Having only the stack as writable memory limits means we cannot use 3041normal global data to share information beween the code. But it 3042turned out that the implementation of U-Boot can be greatly 3043simplified by making a global data structure (gd_t) available to all 3044functions. We could pass a pointer to this data as argument to _all_ 3045functions, but this would bloat the code. Instead we use a feature of 3046the GCC compiler (Global Register Variables) to share the data: we 3047place a pointer (gd) to the global data into a register which we 3048reserve for this purpose. 3049 3050When choosing a register for such a purpose we are restricted by the 3051relevant (E)ABI specifications for the current architecture, and by 3052GCC's implementation. 3053 3054For PowerPC, the following registers have specific use: 3055 R1: stack pointer 3056 R2: TOC pointer 3057 R3-R4: parameter passing and return values 3058 R5-R10: parameter passing 3059 R13: small data area pointer 3060 R30: GOT pointer 3061 R31: frame pointer 3062 3063 (U-Boot also uses R14 as internal GOT pointer.) 3064 3065 ==> U-Boot will use R29 to hold a pointer to the global data 3066 3067 Note: on PPC, we could use a static initializer (since the 3068 address of the global data structure is known at compile time), 3069 but it turned out that reserving a register results in somewhat 3070 smaller code - although the code savings are not that big (on 3071 average for all boards 752 bytes for the whole U-Boot image, 3072 624 text + 127 data). 3073 3074On ARM, the following registers are used: 3075 3076 R0: function argument word/integer result 3077 R1-R3: function argument word 3078 R9: GOT pointer 3079 R10: stack limit (used only if stack checking if enabled) 3080 R11: argument (frame) pointer 3081 R12: temporary workspace 3082 R13: stack pointer 3083 R14: link register 3084 R15: program counter 3085 3086 ==> U-Boot will use R8 to hold a pointer to the global data 3087 3088 3089Memory Management: 3090------------------ 3091 3092U-Boot runs in system state and uses physical addresses, i.e. the 3093MMU is not used either for address mapping nor for memory protection. 3094 3095The available memory is mapped to fixed addresses using the memory 3096controller. In this process, a contiguous block is formed for each 3097memory type (Flash, SDRAM, SRAM), even when it consists of several 3098physical memory banks. 3099 3100U-Boot is installed in the first 128 kB of the first Flash bank (on 3101TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3102booting and sizing and initializing DRAM, the code relocates itself 3103to the upper end of DRAM. Immediately below the U-Boot code some 3104memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3105configuration setting]. Below that, a structure with global Board 3106Info data is placed, followed by the stack (growing downward). 3107 3108Additionally, some exception handler code is copied to the low 8 kB 3109of DRAM (0x00000000 ... 0x00001FFF). 3110 3111So a typical memory configuration with 16 MB of DRAM could look like 3112this: 3113 3114 0x0000 0000 Exception Vector code 3115 : 3116 0x0000 1FFF 3117 0x0000 2000 Free for Application Use 3118 : 3119 : 3120 3121 : 3122 : 3123 0x00FB FF20 Monitor Stack (Growing downward) 3124 0x00FB FFAC Board Info Data and permanent copy of global data 3125 0x00FC 0000 Malloc Arena 3126 : 3127 0x00FD FFFF 3128 0x00FE 0000 RAM Copy of Monitor Code 3129 ... eventually: LCD or video framebuffer 3130 ... eventually: pRAM (Protected RAM - unchanged by reset) 3131 0x00FF FFFF [End of RAM] 3132 3133 3134System Initialization: 3135---------------------- 3136 3137In the reset configuration, U-Boot starts at the reset entry point 3138(on most PowerPC systens at address 0x00000100). Because of the reset 3139configuration for CS0# this is a mirror of the onboard Flash memory. 3140To be able to re-map memory U-Boot then jumps to its link address. 3141To be able to implement the initialization code in C, a (small!) 3142initial stack is set up in the internal Dual Ported RAM (in case CPUs 3143which provide such a feature like MPC8xx or MPC8260), or in a locked 3144part of the data cache. After that, U-Boot initializes the CPU core, 3145the caches and the SIU. 3146 3147Next, all (potentially) available memory banks are mapped using a 3148preliminary mapping. For example, we put them on 512 MB boundaries 3149(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3150on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3151programmed for SDRAM access. Using the temporary configuration, a 3152simple memory test is run that determines the size of the SDRAM 3153banks. 3154 3155When there is more than one SDRAM bank, and the banks are of 3156different size, the largest is mapped first. For equal size, the first 3157bank (CS2#) is mapped first. The first mapping is always for address 31580x00000000, with any additional banks following immediately to create 3159contiguous memory starting from 0. 3160 3161Then, the monitor installs itself at the upper end of the SDRAM area 3162and allocates memory for use by malloc() and for the global Board 3163Info data; also, the exception vector code is copied to the low RAM 3164pages, and the final stack is set up. 3165 3166Only after this relocation will you have a "normal" C environment; 3167until that you are restricted in several ways, mostly because you are 3168running from ROM, and because the code will have to be relocated to a 3169new address in RAM. 3170 3171 3172U-Boot Porting Guide: 3173---------------------- 3174 3175[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3176list, October 2002] 3177 3178 3179int main (int argc, char *argv[]) 3180{ 3181 sighandler_t no_more_time; 3182 3183 signal (SIGALRM, no_more_time); 3184 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3185 3186 if (available_money > available_manpower) { 3187 pay consultant to port U-Boot; 3188 return 0; 3189 } 3190 3191 Download latest U-Boot source; 3192 3193 Subscribe to u-boot-users mailing list; 3194 3195 if (clueless) { 3196 email ("Hi, I am new to U-Boot, how do I get started?"); 3197 } 3198 3199 while (learning) { 3200 Read the README file in the top level directory; 3201 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3202 Read the source, Luke; 3203 } 3204 3205 if (available_money > toLocalCurrency ($2500)) { 3206 Buy a BDI2000; 3207 } else { 3208 Add a lot of aggravation and time; 3209 } 3210 3211 Create your own board support subdirectory; 3212 3213 Create your own board config file; 3214 3215 while (!running) { 3216 do { 3217 Add / modify source code; 3218 } until (compiles); 3219 Debug; 3220 if (clueless) 3221 email ("Hi, I am having problems..."); 3222 } 3223 Send patch file to Wolfgang; 3224 3225 return 0; 3226} 3227 3228void no_more_time (int sig) 3229{ 3230 hire_a_guru(); 3231} 3232 3233 3234Coding Standards: 3235----------------- 3236 3237All contributions to U-Boot should conform to the Linux kernel 3238coding style; see the file "Documentation/CodingStyle" in your Linux 3239kernel source directory. 3240 3241Please note that U-Boot is implemented in C (and to some small parts 3242in Assembler); no C++ is used, so please do not use C++ style 3243comments (//) in your code. 3244 3245Please also stick to the following formatting rules: 3246- remove any trailing white space 3247- use TAB characters for indentation, not spaces 3248- make sure NOT to use DOS '\r\n' line feeds 3249- do not add more than 2 empty lines to source files 3250- do not add trailing empty lines to source files 3251 3252Submissions which do not conform to the standards may be returned 3253with a request to reformat the changes. 3254 3255 3256Submitting Patches: 3257------------------- 3258 3259Since the number of patches for U-Boot is growing, we need to 3260establish some rules. Submissions which do not conform to these rules 3261may be rejected, even when they contain important and valuable stuff. 3262 3263 3264When you send a patch, please include the following information with 3265it: 3266 3267* For bug fixes: a description of the bug and how your patch fixes 3268 this bug. Please try to include a way of demonstrating that the 3269 patch actually fixes something. 3270 3271* For new features: a description of the feature and your 3272 implementation. 3273 3274* A CHANGELOG entry as plaintext (separate from the patch) 3275 3276* For major contributions, your entry to the CREDITS file 3277 3278* When you add support for a new board, don't forget to add this 3279 board to the MAKEALL script, too. 3280 3281* If your patch adds new configuration options, don't forget to 3282 document these in the README file. 3283 3284* The patch itself. If you are accessing the CVS repository use "cvs 3285 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3286 version of diff does not support these options, then get the latest 3287 version of GNU diff. 3288 3289 The current directory when running this command shall be the top 3290 level directory of the U-Boot source tree, or it's parent directory 3291 (i. e. please make sure that your patch includes sufficient 3292 directory information for the affected files). 3293 3294 We accept patches as plain text, MIME attachments or as uuencoded 3295 gzipped text. 3296 3297* If one logical set of modifications affects or creates several 3298 files, all these changes shall be submitted in a SINGLE patch file. 3299 3300* Changesets that contain different, unrelated modifications shall be 3301 submitted as SEPARATE patches, one patch per changeset. 3302 3303 3304Notes: 3305 3306* Before sending the patch, run the MAKEALL script on your patched 3307 source tree and make sure that no errors or warnings are reported 3308 for any of the boards. 3309 3310* Keep your modifications to the necessary minimum: A patch 3311 containing several unrelated changes or arbitrary reformats will be 3312 returned with a request to re-formatting / split it. 3313 3314* If you modify existing code, make sure that your new code does not 3315 add to the memory footprint of the code ;-) Small is beautiful! 3316 When adding new features, these should compile conditionally only 3317 (using #ifdef), and the resulting code with the new feature 3318 disabled must not need more memory than the old code without your 3319 modification. 3320