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_sbc8560 273 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SM850 274 CONFIG_DU405 CONFIG_MHPC CONFIG_SPD823TS 275 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_STXGP3 276 CONFIG_EBONY CONFIG_MOUSSE CONFIG_SXNI855T 277 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM823L 278 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM8260 279 CONFIG_ep8260 CONFIG_MPC8560ADS CONFIG_TQM850L 280 CONFIG_ERIC CONFIG_MUSENKI CONFIG_TQM855L 281 CONFIG_ESTEEM192E CONFIG_MVS1 CONFIG_TQM860L 282 CONFIG_ETX094 CONFIG_NETPHONE CONFIG_TTTech 283 CONFIG_EVB64260 CONFIG_NETTA CONFIG_UTX8245 284 CONFIG_FADS823 CONFIG_NETVIA CONFIG_V37 285 CONFIG_FADS850SAR CONFIG_NX823 CONFIG_W7OLMC 286 CONFIG_FADS860T CONFIG_OCRTC CONFIG_W7OLMG 287 CONFIG_FLAGADM CONFIG_ORSG CONFIG_WALNUT405 288 CONFIG_FPS850L CONFIG_OXC CONFIG_ZPC1900 289 CONFIG_FPS860L CONFIG_ZUMA 290 291 ARM based boards: 292 ----------------- 293 294 CONFIG_AT91RM9200DK, CONFIG_DNP1110, CONFIG_EP7312, 295 CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE, CONFIG_IMPA7, 296 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610, CONFIG_LART, 297 CONFIG_LPD7A400 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, 298 CONFIG_SHANNON, CONFIG_P2_OMAP730, CONFIG_SMDK2400, 299 CONFIG_SMDK2410, CONFIG_TRAB, CONFIG_VCMA9 300 301 MicroBlaze based boards: 302 ------------------------ 303 304 CONFIG_SUZAKU 305 306 307- CPU Module Type: (if CONFIG_COGENT is defined) 308 Define exactly one of 309 CONFIG_CMA286_60_OLD 310--- FIXME --- not tested yet: 311 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 312 CONFIG_CMA287_23, CONFIG_CMA287_50 313 314- Motherboard Type: (if CONFIG_COGENT is defined) 315 Define exactly one of 316 CONFIG_CMA101, CONFIG_CMA102 317 318- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 319 Define one or more of 320 CONFIG_CMA302 321 322- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 323 Define one or more of 324 CONFIG_LCD_HEARTBEAT - update a character position on 325 the lcd display every second with 326 a "rotator" |\-/|\-/ 327 328- Board flavour: (if CONFIG_MPC8260ADS is defined) 329 CONFIG_ADSTYPE 330 Possible values are: 331 CFG_8260ADS - original MPC8260ADS 332 CFG_8266ADS - MPC8266ADS 333 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR 334 CFG_8272ADS - MPC8272ADS 335 336- MPC824X Family Member (if CONFIG_MPC824X is defined) 337 Define exactly one of 338 CONFIG_MPC8240, CONFIG_MPC8245 339 340- 8xx CPU Options: (if using an MPC8xx cpu) 341 Define one or more of 342 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work 343 e.g. if there is no 32KHz 344 reference PIT/RTC clock 345 346- 859/866 CPU options: (if using a MPC859 or MPC866 CPU): 347 CFG_866_OSCCLK 348 CFG_866_CPUCLK_MIN 349 CFG_866_CPUCLK_MAX 350 CFG_866_CPUCLK_DEFAULT 351 See doc/README.MPC866 352 353 CFG_MEASURE_CPUCLK 354 355 Define this to measure the actual CPU clock instead 356 of relying on the correctness of the configured 357 values. Mostly useful for board bringup to make sure 358 the PLL is locked at the intended frequency. Note 359 that this requires a (stable) reference clock (32 kHz 360 RTC clock), 361 362- Linux Kernel Interface: 363 CONFIG_CLOCKS_IN_MHZ 364 365 U-Boot stores all clock information in Hz 366 internally. For binary compatibility with older Linux 367 kernels (which expect the clocks passed in the 368 bd_info data to be in MHz) the environment variable 369 "clocks_in_mhz" can be defined so that U-Boot 370 converts clock data to MHZ before passing it to the 371 Linux kernel. 372 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 373 "clocks_in_mhz=1" is automatically included in the 374 default environment. 375 376 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 377 378 When transfering memsize parameter to linux, some versions 379 expect it to be in bytes, others in MB. 380 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 381 382- Console Interface: 383 Depending on board, define exactly one serial port 384 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 385 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 386 console by defining CONFIG_8xx_CONS_NONE 387 388 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 389 port routines must be defined elsewhere 390 (i.e. serial_init(), serial_getc(), ...) 391 392 CONFIG_CFB_CONSOLE 393 Enables console device for a color framebuffer. Needs following 394 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 395 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 396 (default big endian) 397 VIDEO_HW_RECTFILL graphic chip supports 398 rectangle fill 399 (cf. smiLynxEM) 400 VIDEO_HW_BITBLT graphic chip supports 401 bit-blit (cf. smiLynxEM) 402 VIDEO_VISIBLE_COLS visible pixel columns 403 (cols=pitch) 404 VIDEO_VISIBLE_ROWS visible pixel rows 405 VIDEO_PIXEL_SIZE bytes per pixel 406 VIDEO_DATA_FORMAT graphic data format 407 (0-5, cf. cfb_console.c) 408 VIDEO_FB_ADRS framebuffer address 409 VIDEO_KBD_INIT_FCT keyboard int fct 410 (i.e. i8042_kbd_init()) 411 VIDEO_TSTC_FCT test char fct 412 (i.e. i8042_tstc) 413 VIDEO_GETC_FCT get char fct 414 (i.e. i8042_getc) 415 CONFIG_CONSOLE_CURSOR cursor drawing on/off 416 (requires blink timer 417 cf. i8042.c) 418 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 419 CONFIG_CONSOLE_TIME display time/date info in 420 upper right corner 421 (requires CFG_CMD_DATE) 422 CONFIG_VIDEO_LOGO display Linux logo in 423 upper left corner 424 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 425 linux_logo.h for logo. 426 Requires CONFIG_VIDEO_LOGO 427 CONFIG_CONSOLE_EXTRA_INFO 428 addional board info beside 429 the logo 430 431 When CONFIG_CFB_CONSOLE is defined, video console is 432 default i/o. Serial console can be forced with 433 environment 'console=serial'. 434 435 When CONFIG_SILENT_CONSOLE is defined, all console 436 messages (by U-Boot and Linux!) can be silenced with 437 the "silent" environment variable. See 438 doc/README.silent for more information. 439 440- Console Baudrate: 441 CONFIG_BAUDRATE - in bps 442 Select one of the baudrates listed in 443 CFG_BAUDRATE_TABLE, see below. 444 CFG_BRGCLK_PRESCALE, baudrate prescale 445 446- Interrupt driven serial port input: 447 CONFIG_SERIAL_SOFTWARE_FIFO 448 449 PPC405GP only. 450 Use an interrupt handler for receiving data on the 451 serial port. It also enables using hardware handshake 452 (RTS/CTS) and UART's built-in FIFO. Set the number of 453 bytes the interrupt driven input buffer should have. 454 455 Leave undefined to disable this feature, including 456 disable the buffer and hardware handshake. 457 458- Console UART Number: 459 CONFIG_UART1_CONSOLE 460 461 IBM PPC4xx only. 462 If defined internal UART1 (and not UART0) is used 463 as default U-Boot console. 464 465- Boot Delay: CONFIG_BOOTDELAY - in seconds 466 Delay before automatically booting the default image; 467 set to -1 to disable autoboot. 468 469 See doc/README.autoboot for these options that 470 work with CONFIG_BOOTDELAY. None are required. 471 CONFIG_BOOT_RETRY_TIME 472 CONFIG_BOOT_RETRY_MIN 473 CONFIG_AUTOBOOT_KEYED 474 CONFIG_AUTOBOOT_PROMPT 475 CONFIG_AUTOBOOT_DELAY_STR 476 CONFIG_AUTOBOOT_STOP_STR 477 CONFIG_AUTOBOOT_DELAY_STR2 478 CONFIG_AUTOBOOT_STOP_STR2 479 CONFIG_ZERO_BOOTDELAY_CHECK 480 CONFIG_RESET_TO_RETRY 481 482- Autoboot Command: 483 CONFIG_BOOTCOMMAND 484 Only needed when CONFIG_BOOTDELAY is enabled; 485 define a command string that is automatically executed 486 when no character is read on the console interface 487 within "Boot Delay" after reset. 488 489 CONFIG_BOOTARGS 490 This can be used to pass arguments to the bootm 491 command. The value of CONFIG_BOOTARGS goes into the 492 environment value "bootargs". 493 494 CONFIG_RAMBOOT and CONFIG_NFSBOOT 495 The value of these goes into the environment as 496 "ramboot" and "nfsboot" respectively, and can be used 497 as a convenience, when switching between booting from 498 ram and nfs. 499 500- Pre-Boot Commands: 501 CONFIG_PREBOOT 502 503 When this option is #defined, the existence of the 504 environment variable "preboot" will be checked 505 immediately before starting the CONFIG_BOOTDELAY 506 countdown and/or running the auto-boot command resp. 507 entering interactive mode. 508 509 This feature is especially useful when "preboot" is 510 automatically generated or modified. For an example 511 see the LWMON board specific code: here "preboot" is 512 modified when the user holds down a certain 513 combination of keys on the (special) keyboard when 514 booting the systems 515 516- Serial Download Echo Mode: 517 CONFIG_LOADS_ECHO 518 If defined to 1, all characters received during a 519 serial download (using the "loads" command) are 520 echoed back. This might be needed by some terminal 521 emulations (like "cu"), but may as well just take 522 time on others. This setting #define's the initial 523 value of the "loads_echo" environment variable. 524 525- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 526 CONFIG_KGDB_BAUDRATE 527 Select one of the baudrates listed in 528 CFG_BAUDRATE_TABLE, see below. 529 530- Monitor Functions: 531 CONFIG_COMMANDS 532 Most monitor functions can be selected (or 533 de-selected) by adjusting the definition of 534 CONFIG_COMMANDS; to select individual functions, 535 #define CONFIG_COMMANDS by "OR"ing any of the 536 following values: 537 538 #define enables commands: 539 ------------------------- 540 CFG_CMD_ASKENV * ask for env variable 541 CFG_CMD_AUTOSCRIPT Autoscript Support 542 CFG_CMD_BDI bdinfo 543 CFG_CMD_BEDBUG Include BedBug Debugger 544 CFG_CMD_BMP * BMP support 545 CFG_CMD_BOOTD bootd 546 CFG_CMD_CACHE icache, dcache 547 CFG_CMD_CONSOLE coninfo 548 CFG_CMD_DATE * support for RTC, date/time... 549 CFG_CMD_DHCP DHCP support 550 CFG_CMD_DIAG * Diagnostics 551 CFG_CMD_DOC * Disk-On-Chip Support 552 CFG_CMD_DTT Digital Therm and Thermostat 553 CFG_CMD_ECHO * echo arguments 554 CFG_CMD_EEPROM * EEPROM read/write support 555 CFG_CMD_ELF bootelf, bootvx 556 CFG_CMD_ENV saveenv 557 CFG_CMD_FDC * Floppy Disk Support 558 CFG_CMD_FAT FAT partition support 559 CFG_CMD_FDOS * Dos diskette Support 560 CFG_CMD_FLASH flinfo, erase, protect 561 CFG_CMD_FPGA FPGA device initialization support 562 CFG_CMD_HWFLOW * RTS/CTS hw flow control 563 CFG_CMD_I2C * I2C serial bus support 564 CFG_CMD_IDE * IDE harddisk support 565 CFG_CMD_IMI iminfo 566 CFG_CMD_IMLS List all found images 567 CFG_CMD_IMMAP * IMMR dump support 568 CFG_CMD_IRQ * irqinfo 569 CFG_CMD_ITEST * Integer/string test of 2 values 570 CFG_CMD_JFFS2 * JFFS2 Support 571 CFG_CMD_KGDB * kgdb 572 CFG_CMD_LOADB loadb 573 CFG_CMD_LOADS loads 574 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 575 loop, mtest 576 CFG_CMD_MISC Misc functions like sleep etc 577 CFG_CMD_MMC MMC memory mapped support 578 CFG_CMD_MII MII utility commands 579 CFG_CMD_NAND * NAND support 580 CFG_CMD_NET bootp, tftpboot, rarpboot 581 CFG_CMD_PCI * pciinfo 582 CFG_CMD_PCMCIA * PCMCIA support 583 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host 584 CFG_CMD_PORTIO * Port I/O 585 CFG_CMD_REGINFO * Register dump 586 CFG_CMD_RUN run command in env variable 587 CFG_CMD_SAVES save S record dump 588 CFG_CMD_SCSI * SCSI Support 589 CFG_CMD_SDRAM * print SDRAM configuration information 590 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 591 CFG_CMD_SPI * SPI serial bus support 592 CFG_CMD_USB * USB support 593 CFG_CMD_VFD * VFD support (TRAB) 594 CFG_CMD_BSP * Board SPecific functions 595 CFG_CMD_CDP * Cisco Discover Protocol support 596 ----------------------------------------------- 597 CFG_CMD_ALL all 598 599 CFG_CMD_DFL Default configuration; at the moment 600 this is includes all commands, except 601 the ones marked with "*" in the list 602 above. 603 604 If you don't define CONFIG_COMMANDS it defaults to 605 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 606 override the default settings in the respective 607 include file. 608 609 EXAMPLE: If you want all functions except of network 610 support you can write: 611 612 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 613 614 615 Note: Don't enable the "icache" and "dcache" commands 616 (configuration option CFG_CMD_CACHE) unless you know 617 what you (and your U-Boot users) are doing. Data 618 cache cannot be enabled on systems like the 8xx or 619 8260 (where accesses to the IMMR region must be 620 uncached), and it cannot be disabled on all other 621 systems where we (mis-) use the data cache to hold an 622 initial stack and some data. 623 624 625 XXX - this list needs to get updated! 626 627- Watchdog: 628 CONFIG_WATCHDOG 629 If this variable is defined, it enables watchdog 630 support. There must be support in the platform specific 631 code for a watchdog. For the 8xx and 8260 CPUs, the 632 SIU Watchdog feature is enabled in the SYPCR 633 register. 634 635- U-Boot Version: 636 CONFIG_VERSION_VARIABLE 637 If this variable is defined, an environment variable 638 named "ver" is created by U-Boot showing the U-Boot 639 version as printed by the "version" command. 640 This variable is readonly. 641 642- Real-Time Clock: 643 644 When CFG_CMD_DATE is selected, the type of the RTC 645 has to be selected, too. Define exactly one of the 646 following options: 647 648 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 649 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 650 CONFIG_RTC_MC146818 - use MC146818 RTC 651 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 652 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 653 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 654 CONFIG_RTC_DS164x - use Dallas DS164x RTC 655 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 656 657 Note that if the RTC uses I2C, then the I2C interface 658 must also be configured. See I2C Support, below. 659 660- Timestamp Support: 661 662 When CONFIG_TIMESTAMP is selected, the timestamp 663 (date and time) of an image is printed by image 664 commands like bootm or iminfo. This option is 665 automatically enabled when you select CFG_CMD_DATE . 666 667- Partition Support: 668 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 669 and/or CONFIG_ISO_PARTITION 670 671 If IDE or SCSI support is enabled (CFG_CMD_IDE or 672 CFG_CMD_SCSI) you must configure support for at least 673 one partition type as well. 674 675- IDE Reset method: 676 CONFIG_IDE_RESET_ROUTINE - this is defined in several 677 board configurations files but used nowhere! 678 679 CONFIG_IDE_RESET - is this is defined, IDE Reset will 680 be performed by calling the function 681 ide_set_reset(int reset) 682 which has to be defined in a board specific file 683 684- ATAPI Support: 685 CONFIG_ATAPI 686 687 Set this to enable ATAPI support. 688 689- LBA48 Support 690 CONFIG_LBA48 691 692 Set this to enable support for disks larger than 137GB 693 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 694 Whithout these , LBA48 support uses 32bit variables and will 'only' 695 support disks up to 2.1TB. 696 697 CFG_64BIT_LBA: 698 When enabled, makes the IDE subsystem use 64bit sector addresses. 699 Default is 32bit. 700 701- SCSI Support: 702 At the moment only there is only support for the 703 SYM53C8XX SCSI controller; define 704 CONFIG_SCSI_SYM53C8XX to enable it. 705 706 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 707 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 708 CFG_SCSI_MAX_LUN] can be adjusted to define the 709 maximum numbers of LUNs, SCSI ID's and target 710 devices. 711 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 712 713- NETWORK Support (PCI): 714 CONFIG_E1000 715 Support for Intel 8254x gigabit chips. 716 717 CONFIG_EEPRO100 718 Support for Intel 82557/82559/82559ER chips. 719 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 720 write routine for first time initialisation. 721 722 CONFIG_TULIP 723 Support for Digital 2114x chips. 724 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 725 modem chip initialisation (KS8761/QS6611). 726 727 CONFIG_NATSEMI 728 Support for National dp83815 chips. 729 730 CONFIG_NS8382X 731 Support for National dp8382[01] gigabit chips. 732 733- NETWORK Support (other): 734 735 CONFIG_DRIVER_LAN91C96 736 Support for SMSC's LAN91C96 chips. 737 738 CONFIG_LAN91C96_BASE 739 Define this to hold the physical address 740 of the LAN91C96's I/O space 741 742 CONFIG_LAN91C96_USE_32_BIT 743 Define this to enable 32 bit addressing 744 745 CONFIG_DRIVER_SMC91111 746 Support for SMSC's LAN91C111 chip 747 748 CONFIG_SMC91111_BASE 749 Define this to hold the physical address 750 of the device (I/O space) 751 752 CONFIG_SMC_USE_32_BIT 753 Define this if data bus is 32 bits 754 755 CONFIG_SMC_USE_IOFUNCS 756 Define this to use i/o functions instead of macros 757 (some hardware wont work with macros) 758 759- USB Support: 760 At the moment only the UHCI host controller is 761 supported (PIP405, MIP405, MPC5200); define 762 CONFIG_USB_UHCI to enable it. 763 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 764 end define CONFIG_USB_STORAGE to enable the USB 765 storage devices. 766 Note: 767 Supported are USB Keyboards and USB Floppy drives 768 (TEAC FD-05PUB). 769 MPC5200 USB requires additional defines: 770 CONFIG_USB_CLOCK 771 for 528 MHz Clock: 0x0001bbbb 772 CONFIG_USB_CONFIG 773 for differential drivers: 0x00001000 774 for single ended drivers: 0x00005000 775 776 777- MMC Support: 778 The MMC controller on the Intel PXA is supported. To 779 enable this define CONFIG_MMC. The MMC can be 780 accessed from the boot prompt by mapping the device 781 to physical memory similar to flash. Command line is 782 enabled with CFG_CMD_MMC. The MMC driver also works with 783 the FAT fs. This is enabled with CFG_CMD_FAT. 784 785- Keyboard Support: 786 CONFIG_ISA_KEYBOARD 787 788 Define this to enable standard (PC-Style) keyboard 789 support 790 791 CONFIG_I8042_KBD 792 Standard PC keyboard driver with US (is default) and 793 GERMAN key layout (switch via environment 'keymap=de') support. 794 Export function i8042_kbd_init, i8042_tstc and i8042_getc 795 for cfb_console. Supports cursor blinking. 796 797- Video support: 798 CONFIG_VIDEO 799 800 Define this to enable video support (for output to 801 video). 802 803 CONFIG_VIDEO_CT69000 804 805 Enable Chips & Technologies 69000 Video chip 806 807 CONFIG_VIDEO_SMI_LYNXEM 808 Enable Silicon Motion SMI 712/710/810 Video chip. The 809 video output is selected via environment 'videoout' 810 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 811 assumed. 812 813 For the CT69000 and SMI_LYNXEM drivers, videomode is 814 selected via environment 'videomode'. Two diferent ways 815 are possible: 816 - "videomode=num" 'num' is a standard LiLo mode numbers. 817 Following standard modes are supported (* is default): 818 819 Colors 640x480 800x600 1024x768 1152x864 1280x1024 820 -------------+--------------------------------------------- 821 8 bits | 0x301* 0x303 0x305 0x161 0x307 822 15 bits | 0x310 0x313 0x316 0x162 0x319 823 16 bits | 0x311 0x314 0x317 0x163 0x31A 824 24 bits | 0x312 0x315 0x318 ? 0x31B 825 -------------+--------------------------------------------- 826 (i.e. setenv videomode 317; saveenv; reset;) 827 828 - "videomode=bootargs" all the video parameters are parsed 829 from the bootargs. (See drivers/videomodes.c) 830 831 832 CONFIG_VIDEO_SED13806 833 Enable Epson SED13806 driver. This driver supports 8bpp 834 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 835 or CONFIG_VIDEO_SED13806_16BPP 836 837- Keyboard Support: 838 CONFIG_KEYBOARD 839 840 Define this to enable a custom keyboard support. 841 This simply calls drv_keyboard_init() which must be 842 defined in your board-specific files. 843 The only board using this so far is RBC823. 844 845- LCD Support: CONFIG_LCD 846 847 Define this to enable LCD support (for output to LCD 848 display); also select one of the supported displays 849 by defining one of these: 850 851 CONFIG_NEC_NL6448AC33: 852 853 NEC NL6448AC33-18. Active, color, single scan. 854 855 CONFIG_NEC_NL6448BC20 856 857 NEC NL6448BC20-08. 6.5", 640x480. 858 Active, color, single scan. 859 860 CONFIG_NEC_NL6448BC33_54 861 862 NEC NL6448BC33-54. 10.4", 640x480. 863 Active, color, single scan. 864 865 CONFIG_SHARP_16x9 866 867 Sharp 320x240. Active, color, single scan. 868 It isn't 16x9, and I am not sure what it is. 869 870 CONFIG_SHARP_LQ64D341 871 872 Sharp LQ64D341 display, 640x480. 873 Active, color, single scan. 874 875 CONFIG_HLD1045 876 877 HLD1045 display, 640x480. 878 Active, color, single scan. 879 880 CONFIG_OPTREX_BW 881 882 Optrex CBL50840-2 NF-FW 99 22 M5 883 or 884 Hitachi LMG6912RPFC-00T 885 or 886 Hitachi SP14Q002 887 888 320x240. Black & white. 889 890 Normally display is black on white background; define 891 CFG_WHITE_ON_BLACK to get it inverted. 892 893- Splash Screen Support: CONFIG_SPLASH_SCREEN 894 895 If this option is set, the environment is checked for 896 a variable "splashimage". If found, the usual display 897 of logo, copyright and system information on the LCD 898 is suppressed and the BMP image at the address 899 specified in "splashimage" is loaded instead. The 900 console is redirected to the "nulldev", too. This 901 allows for a "silent" boot where a splash screen is 902 loaded very quickly after power-on. 903 904- Compression support: 905 CONFIG_BZIP2 906 907 If this option is set, support for bzip2 compressed 908 images is included. If not, only uncompressed and gzip 909 compressed images are supported. 910 911 NOTE: the bzip2 algorithm requires a lot of RAM, so 912 the malloc area (as defined by CFG_MALLOC_LEN) should 913 be at least 4MB. 914 915- MII/PHY support: 916 CONFIG_PHY_ADDR 917 918 The address of PHY on MII bus. 919 920 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 921 922 The clock frequency of the MII bus 923 924 CONFIG_PHY_GIGE 925 926 If this option is set, support for speed/duplex 927 detection of Gigabit PHY is included. 928 929 CONFIG_PHY_RESET_DELAY 930 931 Some PHY like Intel LXT971A need extra delay after 932 reset before any MII register access is possible. 933 For such PHY, set this option to the usec delay 934 required. (minimum 300usec for LXT971A) 935 936 CONFIG_PHY_CMD_DELAY (ppc4xx) 937 938 Some PHY like Intel LXT971A need extra delay after 939 command issued before MII status register can be read 940 941- Ethernet address: 942 CONFIG_ETHADDR 943 CONFIG_ETH2ADDR 944 CONFIG_ETH3ADDR 945 946 Define a default value for ethernet address to use 947 for the respective ethernet interface, in case this 948 is not determined automatically. 949 950- IP address: 951 CONFIG_IPADDR 952 953 Define a default value for the IP address to use for 954 the default ethernet interface, in case this is not 955 determined through e.g. bootp. 956 957- Server IP address: 958 CONFIG_SERVERIP 959 960 Defines a default value for theIP address of a TFTP 961 server to contact when using the "tftboot" command. 962 963- BOOTP Recovery Mode: 964 CONFIG_BOOTP_RANDOM_DELAY 965 966 If you have many targets in a network that try to 967 boot using BOOTP, you may want to avoid that all 968 systems send out BOOTP requests at precisely the same 969 moment (which would happen for instance at recovery 970 from a power failure, when all systems will try to 971 boot, thus flooding the BOOTP server. Defining 972 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 973 inserted before sending out BOOTP requests. The 974 following delays are insterted then: 975 976 1st BOOTP request: delay 0 ... 1 sec 977 2nd BOOTP request: delay 0 ... 2 sec 978 3rd BOOTP request: delay 0 ... 4 sec 979 4th and following 980 BOOTP requests: delay 0 ... 8 sec 981 982- DHCP Advanced Options: 983 CONFIG_BOOTP_MASK 984 985 You can fine tune the DHCP functionality by adding 986 these flags to the CONFIG_BOOTP_MASK define: 987 988 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 989 serverip from a DHCP server, it is possible that more 990 than one DNS serverip is offered to the client. 991 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 992 serverip will be stored in the additional environment 993 variable "dnsip2". The first DNS serverip is always 994 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 995 is added to the CONFIG_BOOTP_MASK. 996 997 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 998 to do a dynamic update of a DNS server. To do this, they 999 need the hostname of the DHCP requester. 1000 If CONFIG_BOOP_SEND_HOSTNAME is added to the 1001 CONFIG_BOOTP_MASK, the content of the "hostname" 1002 environment variable is passed as option 12 to 1003 the DHCP server. 1004 1005 - CDP Options: 1006 CONFIG_CDP_DEVICE_ID 1007 1008 The device id used in CDP trigger frames. 1009 1010 CONFIG_CDP_DEVICE_ID_PREFIX 1011 1012 A two character string which is prefixed to the MAC address 1013 of the device. 1014 1015 CONFIG_CDP_PORT_ID 1016 1017 A printf format string which contains the ascii name of 1018 the port. Normally is set to "eth%d" which sets 1019 eth0 for the first ethernet, eth1 for the second etc. 1020 1021 CONFIG_CDP_CAPABILITIES 1022 1023 A 32bit integer which indicates the device capabilities; 1024 0x00000010 for a normal host which does not forwards. 1025 1026 CONFIG_CDP_VERSION 1027 1028 An ascii string containing the version of the software. 1029 1030 CONFIG_CDP_PLATFORM 1031 1032 An ascii string containing the name of the platform. 1033 1034 CONFIG_CDP_TRIGGER 1035 1036 A 32bit integer sent on the trigger. 1037 1038 CONFIG_CDP_POWER_CONSUMPTION 1039 1040 A 16bit integer containing the power consumption of the 1041 device in .1 of milliwatts. 1042 1043 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1044 1045 A byte containing the id of the VLAN. 1046 1047- Status LED: CONFIG_STATUS_LED 1048 1049 Several configurations allow to display the current 1050 status using a LED. For instance, the LED will blink 1051 fast while running U-Boot code, stop blinking as 1052 soon as a reply to a BOOTP request was received, and 1053 start blinking slow once the Linux kernel is running 1054 (supported by a status LED driver in the Linux 1055 kernel). Defining CONFIG_STATUS_LED enables this 1056 feature in U-Boot. 1057 1058- CAN Support: CONFIG_CAN_DRIVER 1059 1060 Defining CONFIG_CAN_DRIVER enables CAN driver support 1061 on those systems that support this (optional) 1062 feature, like the TQM8xxL modules. 1063 1064- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1065 1066 These enable I2C serial bus commands. Defining either of 1067 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1068 include the appropriate I2C driver for the selected cpu. 1069 1070 This will allow you to use i2c commands at the u-boot 1071 command line (as long as you set CFG_CMD_I2C in 1072 CONFIG_COMMANDS) and communicate with i2c based realtime 1073 clock chips. See common/cmd_i2c.c for a description of the 1074 command line interface. 1075 1076 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 1077 1078 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1079 bit-banging) driver instead of CPM or similar hardware 1080 support for I2C. 1081 1082 There are several other quantities that must also be 1083 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1084 1085 In both cases you will need to define CFG_I2C_SPEED 1086 to be the frequency (in Hz) at which you wish your i2c bus 1087 to run and CFG_I2C_SLAVE to be the address of this node (ie 1088 the cpu's i2c node address). 1089 1090 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1091 sets the cpu up as a master node and so its address should 1092 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1093 p.16-473). So, set CFG_I2C_SLAVE to 0. 1094 1095 That's all that's required for CONFIG_HARD_I2C. 1096 1097 If you use the software i2c interface (CONFIG_SOFT_I2C) 1098 then the following macros need to be defined (examples are 1099 from include/configs/lwmon.h): 1100 1101 I2C_INIT 1102 1103 (Optional). Any commands necessary to enable the I2C 1104 controller or configure ports. 1105 1106 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1107 1108 I2C_PORT 1109 1110 (Only for MPC8260 CPU). The I/O port to use (the code 1111 assumes both bits are on the same port). Valid values 1112 are 0..3 for ports A..D. 1113 1114 I2C_ACTIVE 1115 1116 The code necessary to make the I2C data line active 1117 (driven). If the data line is open collector, this 1118 define can be null. 1119 1120 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1121 1122 I2C_TRISTATE 1123 1124 The code necessary to make the I2C data line tri-stated 1125 (inactive). If the data line is open collector, this 1126 define can be null. 1127 1128 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1129 1130 I2C_READ 1131 1132 Code that returns TRUE if the I2C data line is high, 1133 FALSE if it is low. 1134 1135 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1136 1137 I2C_SDA(bit) 1138 1139 If <bit> is TRUE, sets the I2C data line high. If it 1140 is FALSE, it clears it (low). 1141 1142 eg: #define I2C_SDA(bit) \ 1143 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1144 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1145 1146 I2C_SCL(bit) 1147 1148 If <bit> is TRUE, sets the I2C clock line high. If it 1149 is FALSE, it clears it (low). 1150 1151 eg: #define I2C_SCL(bit) \ 1152 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1153 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1154 1155 I2C_DELAY 1156 1157 This delay is invoked four times per clock cycle so this 1158 controls the rate of data transfer. The data rate thus 1159 is 1 / (I2C_DELAY * 4). Often defined to be something 1160 like: 1161 1162 #define I2C_DELAY udelay(2) 1163 1164 CFG_I2C_INIT_BOARD 1165 1166 When a board is reset during an i2c bus transfer 1167 chips might think that the current transfer is still 1168 in progress. On some boards it is possible to access 1169 the i2c SCLK line directly, either by using the 1170 processor pin as a GPIO or by having a second pin 1171 connected to the bus. If this option is defined a 1172 custom i2c_init_board() routine in boards/xxx/board.c 1173 is run early in the boot sequence. 1174 1175 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1176 1177 This option enables configuration of bi_iic_fast[] flags 1178 in u-boot bd_info structure based on u-boot environment 1179 variable "i2cfast". (see also i2cfast) 1180 1181- SPI Support: CONFIG_SPI 1182 1183 Enables SPI driver (so far only tested with 1184 SPI EEPROM, also an instance works with Crystal A/D and 1185 D/As on the SACSng board) 1186 1187 CONFIG_SPI_X 1188 1189 Enables extended (16-bit) SPI EEPROM addressing. 1190 (symmetrical to CONFIG_I2C_X) 1191 1192 CONFIG_SOFT_SPI 1193 1194 Enables a software (bit-bang) SPI driver rather than 1195 using hardware support. This is a general purpose 1196 driver that only requires three general I/O port pins 1197 (two outputs, one input) to function. If this is 1198 defined, the board configuration must define several 1199 SPI configuration items (port pins to use, etc). For 1200 an example, see include/configs/sacsng.h. 1201 1202- FPGA Support: CONFIG_FPGA_COUNT 1203 1204 Specify the number of FPGA devices to support. 1205 1206 CONFIG_FPGA 1207 1208 Used to specify the types of FPGA devices. For example, 1209 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1210 1211 CFG_FPGA_PROG_FEEDBACK 1212 1213 Enable printing of hash marks during FPGA configuration. 1214 1215 CFG_FPGA_CHECK_BUSY 1216 1217 Enable checks on FPGA configuration interface busy 1218 status by the configuration function. This option 1219 will require a board or device specific function to 1220 be written. 1221 1222 CONFIG_FPGA_DELAY 1223 1224 If defined, a function that provides delays in the FPGA 1225 configuration driver. 1226 1227 CFG_FPGA_CHECK_CTRLC 1228 Allow Control-C to interrupt FPGA configuration 1229 1230 CFG_FPGA_CHECK_ERROR 1231 1232 Check for configuration errors during FPGA bitfile 1233 loading. For example, abort during Virtex II 1234 configuration if the INIT_B line goes low (which 1235 indicated a CRC error). 1236 1237 CFG_FPGA_WAIT_INIT 1238 1239 Maximum time to wait for the INIT_B line to deassert 1240 after PROB_B has been deasserted during a Virtex II 1241 FPGA configuration sequence. The default time is 500 1242 mS. 1243 1244 CFG_FPGA_WAIT_BUSY 1245 1246 Maximum time to wait for BUSY to deassert during 1247 Virtex II FPGA configuration. The default is 5 mS. 1248 1249 CFG_FPGA_WAIT_CONFIG 1250 1251 Time to wait after FPGA configuration. The default is 1252 200 mS. 1253 1254- Configuration Management: 1255 CONFIG_IDENT_STRING 1256 1257 If defined, this string will be added to the U-Boot 1258 version information (U_BOOT_VERSION) 1259 1260- Vendor Parameter Protection: 1261 1262 U-Boot considers the values of the environment 1263 variables "serial#" (Board Serial Number) and 1264 "ethaddr" (Ethernet Address) to be parameters that 1265 are set once by the board vendor / manufacturer, and 1266 protects these variables from casual modification by 1267 the user. Once set, these variables are read-only, 1268 and write or delete attempts are rejected. You can 1269 change this behviour: 1270 1271 If CONFIG_ENV_OVERWRITE is #defined in your config 1272 file, the write protection for vendor parameters is 1273 completely disabled. Anybody can change or delete 1274 these parameters. 1275 1276 Alternatively, if you #define _both_ CONFIG_ETHADDR 1277 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1278 ethernet address is installed in the environment, 1279 which can be changed exactly ONCE by the user. [The 1280 serial# is unaffected by this, i. e. it remains 1281 read-only.] 1282 1283- Protected RAM: 1284 CONFIG_PRAM 1285 1286 Define this variable to enable the reservation of 1287 "protected RAM", i. e. RAM which is not overwritten 1288 by U-Boot. Define CONFIG_PRAM to hold the number of 1289 kB you want to reserve for pRAM. You can overwrite 1290 this default value by defining an environment 1291 variable "pram" to the number of kB you want to 1292 reserve. Note that the board info structure will 1293 still show the full amount of RAM. If pRAM is 1294 reserved, a new environment variable "mem" will 1295 automatically be defined to hold the amount of 1296 remaining RAM in a form that can be passed as boot 1297 argument to Linux, for instance like that: 1298 1299 setenv bootargs ... mem=\$(mem) 1300 saveenv 1301 1302 This way you can tell Linux not to use this memory, 1303 either, which results in a memory region that will 1304 not be affected by reboots. 1305 1306 *WARNING* If your board configuration uses automatic 1307 detection of the RAM size, you must make sure that 1308 this memory test is non-destructive. So far, the 1309 following board configurations are known to be 1310 "pRAM-clean": 1311 1312 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1313 HERMES, IP860, RPXlite, LWMON, LANTEC, 1314 PCU_E, FLAGADM, TQM8260 1315 1316- Error Recovery: 1317 CONFIG_PANIC_HANG 1318 1319 Define this variable to stop the system in case of a 1320 fatal error, so that you have to reset it manually. 1321 This is probably NOT a good idea for an embedded 1322 system where you want to system to reboot 1323 automatically as fast as possible, but it may be 1324 useful during development since you can try to debug 1325 the conditions that lead to the situation. 1326 1327 CONFIG_NET_RETRY_COUNT 1328 1329 This variable defines the number of retries for 1330 network operations like ARP, RARP, TFTP, or BOOTP 1331 before giving up the operation. If not defined, a 1332 default value of 5 is used. 1333 1334- Command Interpreter: 1335 CFG_AUTO_COMPLETE 1336 1337 Enable auto completion of commands using TAB. 1338 1339 CFG_HUSH_PARSER 1340 1341 Define this variable to enable the "hush" shell (from 1342 Busybox) as command line interpreter, thus enabling 1343 powerful command line syntax like 1344 if...then...else...fi conditionals or `&&' and '||' 1345 constructs ("shell scripts"). 1346 1347 If undefined, you get the old, much simpler behaviour 1348 with a somewhat smaller memory footprint. 1349 1350 1351 CFG_PROMPT_HUSH_PS2 1352 1353 This defines the secondary prompt string, which is 1354 printed when the command interpreter needs more input 1355 to complete a command. Usually "> ". 1356 1357 Note: 1358 1359 In the current implementation, the local variables 1360 space and global environment variables space are 1361 separated. Local variables are those you define by 1362 simply typing `name=value'. To access a local 1363 variable later on, you have write `$name' or 1364 `${name}'; to execute the contents of a variable 1365 directly type `$name' at the command prompt. 1366 1367 Global environment variables are those you use 1368 setenv/printenv to work with. To run a command stored 1369 in such a variable, you need to use the run command, 1370 and you must not use the '$' sign to access them. 1371 1372 To store commands and special characters in a 1373 variable, please use double quotation marks 1374 surrounding the whole text of the variable, instead 1375 of the backslashes before semicolons and special 1376 symbols. 1377 1378- Default Environment: 1379 CONFIG_EXTRA_ENV_SETTINGS 1380 1381 Define this to contain any number of null terminated 1382 strings (variable = value pairs) that will be part of 1383 the default environment compiled into the boot image. 1384 1385 For example, place something like this in your 1386 board's config file: 1387 1388 #define CONFIG_EXTRA_ENV_SETTINGS \ 1389 "myvar1=value1\0" \ 1390 "myvar2=value2\0" 1391 1392 Warning: This method is based on knowledge about the 1393 internal format how the environment is stored by the 1394 U-Boot code. This is NOT an official, exported 1395 interface! Although it is unlikely that this format 1396 will change soon, there is no guarantee either. 1397 You better know what you are doing here. 1398 1399 Note: overly (ab)use of the default environment is 1400 discouraged. Make sure to check other ways to preset 1401 the environment like the autoscript function or the 1402 boot command first. 1403 1404- DataFlash Support: 1405 CONFIG_HAS_DATAFLASH 1406 1407 Defining this option enables DataFlash features and 1408 allows to read/write in Dataflash via the standard 1409 commands cp, md... 1410 1411- SystemACE Support: 1412 CONFIG_SYSTEMACE 1413 1414 Adding this option adds support for Xilinx SystemACE 1415 chips attached via some sort of local bus. The address 1416 of the chip must alsh be defined in the 1417 CFG_SYSTEMACE_BASE macro. For example: 1418 1419 #define CONFIG_SYSTEMACE 1420 #define CFG_SYSTEMACE_BASE 0xf0000000 1421 1422 When SystemACE support is added, the "ace" device type 1423 becomes available to the fat commands, i.e. fatls. 1424 1425- Show boot progress: 1426 CONFIG_SHOW_BOOT_PROGRESS 1427 1428 Defining this option allows to add some board- 1429 specific code (calling a user-provided function 1430 "show_boot_progress(int)") that enables you to show 1431 the system's boot progress on some display (for 1432 example, some LED's) on your board. At the moment, 1433 the following checkpoints are implemented: 1434 1435 Arg Where When 1436 1 common/cmd_bootm.c before attempting to boot an image 1437 -1 common/cmd_bootm.c Image header has bad magic number 1438 2 common/cmd_bootm.c Image header has correct magic number 1439 -2 common/cmd_bootm.c Image header has bad checksum 1440 3 common/cmd_bootm.c Image header has correct checksum 1441 -3 common/cmd_bootm.c Image data has bad checksum 1442 4 common/cmd_bootm.c Image data has correct checksum 1443 -4 common/cmd_bootm.c Image is for unsupported architecture 1444 5 common/cmd_bootm.c Architecture check OK 1445 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1446 6 common/cmd_bootm.c Image Type check OK 1447 -6 common/cmd_bootm.c gunzip uncompression error 1448 -7 common/cmd_bootm.c Unimplemented compression type 1449 7 common/cmd_bootm.c Uncompression OK 1450 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1451 8 common/cmd_bootm.c Image Type check OK 1452 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1453 9 common/cmd_bootm.c Start initial ramdisk verification 1454 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1455 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1456 10 common/cmd_bootm.c Ramdisk header is OK 1457 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1458 11 common/cmd_bootm.c Ramdisk data has correct checksum 1459 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1460 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1461 13 common/cmd_bootm.c Start multifile image verification 1462 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1463 15 common/cmd_bootm.c All preparation done, transferring control to OS 1464 1465 -30 lib_ppc/board.c Fatal error, hang the system 1466 -31 post/post.c POST test failed, detected by post_output_backlog() 1467 -32 post/post.c POST test failed, detected by post_run_single() 1468 1469 -1 common/cmd_doc.c Bad usage of "doc" command 1470 -1 common/cmd_doc.c No boot device 1471 -1 common/cmd_doc.c Unknown Chip ID on boot device 1472 -1 common/cmd_doc.c Read Error on boot device 1473 -1 common/cmd_doc.c Image header has bad magic number 1474 1475 -1 common/cmd_ide.c Bad usage of "ide" command 1476 -1 common/cmd_ide.c No boot device 1477 -1 common/cmd_ide.c Unknown boot device 1478 -1 common/cmd_ide.c Unknown partition table 1479 -1 common/cmd_ide.c Invalid partition type 1480 -1 common/cmd_ide.c Read Error on boot device 1481 -1 common/cmd_ide.c Image header has bad magic number 1482 1483 -1 common/cmd_nand.c Bad usage of "nand" command 1484 -1 common/cmd_nand.c No boot device 1485 -1 common/cmd_nand.c Unknown Chip ID on boot device 1486 -1 common/cmd_nand.c Read Error on boot device 1487 -1 common/cmd_nand.c Image header has bad magic number 1488 1489 -1 common/env_common.c Environment has a bad CRC, using default 1490 1491 1492Modem Support: 1493-------------- 1494 1495[so far only for SMDK2400 and TRAB boards] 1496 1497- Modem support endable: 1498 CONFIG_MODEM_SUPPORT 1499 1500- RTS/CTS Flow control enable: 1501 CONFIG_HWFLOW 1502 1503- Modem debug support: 1504 CONFIG_MODEM_SUPPORT_DEBUG 1505 1506 Enables debugging stuff (char screen[1024], dbg()) 1507 for modem support. Useful only with BDI2000. 1508 1509- Interrupt support (PPC): 1510 1511 There are common interrupt_init() and timer_interrupt() 1512 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1513 for cpu specific initialization. interrupt_init_cpu() 1514 should set decrementer_count to appropriate value. If 1515 cpu resets decrementer automatically after interrupt 1516 (ppc4xx) it should set decrementer_count to zero. 1517 timer_interrupt() calls timer_interrupt_cpu() for cpu 1518 specific handling. If board has watchdog / status_led 1519 / other_activity_monitor it works automatically from 1520 general timer_interrupt(). 1521 1522- General: 1523 1524 In the target system modem support is enabled when a 1525 specific key (key combination) is pressed during 1526 power-on. Otherwise U-Boot will boot normally 1527 (autoboot). The key_pressed() fuction is called from 1528 board_init(). Currently key_pressed() is a dummy 1529 function, returning 1 and thus enabling modem 1530 initialization. 1531 1532 If there are no modem init strings in the 1533 environment, U-Boot proceed to autoboot; the 1534 previous output (banner, info printfs) will be 1535 supressed, though. 1536 1537 See also: doc/README.Modem 1538 1539 1540Configuration Settings: 1541----------------------- 1542 1543- CFG_LONGHELP: Defined when you want long help messages included; 1544 undefine this when you're short of memory. 1545 1546- CFG_PROMPT: This is what U-Boot prints on the console to 1547 prompt for user input. 1548 1549- CFG_CBSIZE: Buffer size for input from the Console 1550 1551- CFG_PBSIZE: Buffer size for Console output 1552 1553- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1554 1555- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1556 the application (usually a Linux kernel) when it is 1557 booted 1558 1559- CFG_BAUDRATE_TABLE: 1560 List of legal baudrate settings for this board. 1561 1562- CFG_CONSOLE_INFO_QUIET 1563 Suppress display of console information at boot. 1564 1565- CFG_CONSOLE_IS_IN_ENV 1566 If the board specific function 1567 extern int overwrite_console (void); 1568 returns 1, the stdin, stderr and stdout are switched to the 1569 serial port, else the settings in the environment are used. 1570 1571- CFG_CONSOLE_OVERWRITE_ROUTINE 1572 Enable the call to overwrite_console(). 1573 1574- CFG_CONSOLE_ENV_OVERWRITE 1575 Enable overwrite of previous console environment settings. 1576 1577- CFG_MEMTEST_START, CFG_MEMTEST_END: 1578 Begin and End addresses of the area used by the 1579 simple memory test. 1580 1581- CFG_ALT_MEMTEST: 1582 Enable an alternate, more extensive memory test. 1583 1584- CFG_MEMTEST_SCRATCH: 1585 Scratch address used by the alternate memory test 1586 You only need to set this if address zero isn't writeable 1587 1588- CFG_TFTP_LOADADDR: 1589 Default load address for network file downloads 1590 1591- CFG_LOADS_BAUD_CHANGE: 1592 Enable temporary baudrate change while serial download 1593 1594- CFG_SDRAM_BASE: 1595 Physical start address of SDRAM. _Must_ be 0 here. 1596 1597- CFG_MBIO_BASE: 1598 Physical start address of Motherboard I/O (if using a 1599 Cogent motherboard) 1600 1601- CFG_FLASH_BASE: 1602 Physical start address of Flash memory. 1603 1604- CFG_MONITOR_BASE: 1605 Physical start address of boot monitor code (set by 1606 make config files to be same as the text base address 1607 (TEXT_BASE) used when linking) - same as 1608 CFG_FLASH_BASE when booting from flash. 1609 1610- CFG_MONITOR_LEN: 1611 Size of memory reserved for monitor code, used to 1612 determine _at_compile_time_ (!) if the environment is 1613 embedded within the U-Boot image, or in a separate 1614 flash sector. 1615 1616- CFG_MALLOC_LEN: 1617 Size of DRAM reserved for malloc() use. 1618 1619- CFG_BOOTMAPSZ: 1620 Maximum size of memory mapped by the startup code of 1621 the Linux kernel; all data that must be processed by 1622 the Linux kernel (bd_info, boot arguments, eventually 1623 initrd image) must be put below this limit. 1624 1625- CFG_MAX_FLASH_BANKS: 1626 Max number of Flash memory banks 1627 1628- CFG_MAX_FLASH_SECT: 1629 Max number of sectors on a Flash chip 1630 1631- CFG_FLASH_ERASE_TOUT: 1632 Timeout for Flash erase operations (in ms) 1633 1634- CFG_FLASH_WRITE_TOUT: 1635 Timeout for Flash write operations (in ms) 1636 1637- CFG_FLASH_LOCK_TOUT 1638 Timeout for Flash set sector lock bit operation (in ms) 1639 1640- CFG_FLASH_UNLOCK_TOUT 1641 Timeout for Flash clear lock bits operation (in ms) 1642 1643- CFG_FLASH_PROTECTION 1644 If defined, hardware flash sectors protection is used 1645 instead of U-Boot software protection. 1646 1647- CFG_DIRECT_FLASH_TFTP: 1648 1649 Enable TFTP transfers directly to flash memory; 1650 without this option such a download has to be 1651 performed in two steps: (1) download to RAM, and (2) 1652 copy from RAM to flash. 1653 1654 The two-step approach is usually more reliable, since 1655 you can check if the download worked before you erase 1656 the flash, but in some situations (when sytem RAM is 1657 too limited to allow for a tempory copy of the 1658 downloaded image) this option may be very useful. 1659 1660- CFG_FLASH_CFI: 1661 Define if the flash driver uses extra elements in the 1662 common flash structure for storing flash geometry. 1663 1664- CFG_FLASH_CFI_DRIVER 1665 This option also enables the building of the cfi_flash driver 1666 in the drivers directory 1667 1668- CFG_RX_ETH_BUFFER: 1669 Defines the number of ethernet receive buffers. On some 1670 ethernet controllers it is recommended to set this value 1671 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1672 buffers can be full shortly after enabling the interface 1673 on high ethernet traffic. 1674 Defaults to 4 if not defined. 1675 1676The following definitions that deal with the placement and management 1677of environment data (variable area); in general, we support the 1678following configurations: 1679 1680- CFG_ENV_IS_IN_FLASH: 1681 1682 Define this if the environment is in flash memory. 1683 1684 a) The environment occupies one whole flash sector, which is 1685 "embedded" in the text segment with the U-Boot code. This 1686 happens usually with "bottom boot sector" or "top boot 1687 sector" type flash chips, which have several smaller 1688 sectors at the start or the end. For instance, such a 1689 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1690 such a case you would place the environment in one of the 1691 4 kB sectors - with U-Boot code before and after it. With 1692 "top boot sector" type flash chips, you would put the 1693 environment in one of the last sectors, leaving a gap 1694 between U-Boot and the environment. 1695 1696 - CFG_ENV_OFFSET: 1697 1698 Offset of environment data (variable area) to the 1699 beginning of flash memory; for instance, with bottom boot 1700 type flash chips the second sector can be used: the offset 1701 for this sector is given here. 1702 1703 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1704 1705 - CFG_ENV_ADDR: 1706 1707 This is just another way to specify the start address of 1708 the flash sector containing the environment (instead of 1709 CFG_ENV_OFFSET). 1710 1711 - CFG_ENV_SECT_SIZE: 1712 1713 Size of the sector containing the environment. 1714 1715 1716 b) Sometimes flash chips have few, equal sized, BIG sectors. 1717 In such a case you don't want to spend a whole sector for 1718 the environment. 1719 1720 - CFG_ENV_SIZE: 1721 1722 If you use this in combination with CFG_ENV_IS_IN_FLASH 1723 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1724 of this flash sector for the environment. This saves 1725 memory for the RAM copy of the environment. 1726 1727 It may also save flash memory if you decide to use this 1728 when your environment is "embedded" within U-Boot code, 1729 since then the remainder of the flash sector could be used 1730 for U-Boot code. It should be pointed out that this is 1731 STRONGLY DISCOURAGED from a robustness point of view: 1732 updating the environment in flash makes it always 1733 necessary to erase the WHOLE sector. If something goes 1734 wrong before the contents has been restored from a copy in 1735 RAM, your target system will be dead. 1736 1737 - CFG_ENV_ADDR_REDUND 1738 CFG_ENV_SIZE_REDUND 1739 1740 These settings describe a second storage area used to hold 1741 a redundand copy of the environment data, so that there is 1742 a valid backup copy in case there is a power failure during 1743 a "saveenv" operation. 1744 1745BE CAREFUL! Any changes to the flash layout, and some changes to the 1746source code will make it necessary to adapt <board>/u-boot.lds* 1747accordingly! 1748 1749 1750- CFG_ENV_IS_IN_NVRAM: 1751 1752 Define this if you have some non-volatile memory device 1753 (NVRAM, battery buffered SRAM) which you want to use for the 1754 environment. 1755 1756 - CFG_ENV_ADDR: 1757 - CFG_ENV_SIZE: 1758 1759 These two #defines are used to determin the memory area you 1760 want to use for environment. It is assumed that this memory 1761 can just be read and written to, without any special 1762 provision. 1763 1764BE CAREFUL! The first access to the environment happens quite early 1765in U-Boot initalization (when we try to get the setting of for the 1766console baudrate). You *MUST* have mappend your NVRAM area then, or 1767U-Boot will hang. 1768 1769Please note that even with NVRAM we still use a copy of the 1770environment in RAM: we could work on NVRAM directly, but we want to 1771keep settings there always unmodified except somebody uses "saveenv" 1772to save the current settings. 1773 1774 1775- CFG_ENV_IS_IN_EEPROM: 1776 1777 Use this if you have an EEPROM or similar serial access 1778 device and a driver for it. 1779 1780 - CFG_ENV_OFFSET: 1781 - CFG_ENV_SIZE: 1782 1783 These two #defines specify the offset and size of the 1784 environment area within the total memory of your EEPROM. 1785 1786 - CFG_I2C_EEPROM_ADDR: 1787 If defined, specified the chip address of the EEPROM device. 1788 The default address is zero. 1789 1790 - CFG_EEPROM_PAGE_WRITE_BITS: 1791 If defined, the number of bits used to address bytes in a 1792 single page in the EEPROM device. A 64 byte page, for example 1793 would require six bits. 1794 1795 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1796 If defined, the number of milliseconds to delay between 1797 page writes. The default is zero milliseconds. 1798 1799 - CFG_I2C_EEPROM_ADDR_LEN: 1800 The length in bytes of the EEPROM memory array address. Note 1801 that this is NOT the chip address length! 1802 1803 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 1804 EEPROM chips that implement "address overflow" are ones 1805 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 1806 address and the extra bits end up in the "chip address" bit 1807 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 1808 byte chips. 1809 1810 Note that we consider the length of the address field to 1811 still be one byte because the extra address bits are hidden 1812 in the chip address. 1813 1814 - CFG_EEPROM_SIZE: 1815 The size in bytes of the EEPROM device. 1816 1817 1818- CFG_ENV_IS_IN_DATAFLASH: 1819 1820 Define this if you have a DataFlash memory device which you 1821 want to use for the environment. 1822 1823 - CFG_ENV_OFFSET: 1824 - CFG_ENV_ADDR: 1825 - CFG_ENV_SIZE: 1826 1827 These three #defines specify the offset and size of the 1828 environment area within the total memory of your DataFlash placed 1829 at the specified address. 1830 1831- CFG_ENV_IS_IN_NAND: 1832 1833 Define this if you have a NAND device which you want to use 1834 for the environment. 1835 1836 - CFG_ENV_OFFSET: 1837 - CFG_ENV_SIZE: 1838 1839 These two #defines specify the offset and size of the environment 1840 area within the first NAND device. 1841 1842- CFG_SPI_INIT_OFFSET 1843 1844 Defines offset to the initial SPI buffer area in DPRAM. The 1845 area is used at an early stage (ROM part) if the environment 1846 is configured to reside in the SPI EEPROM: We need a 520 byte 1847 scratch DPRAM area. It is used between the two initialization 1848 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1849 to be a good choice since it makes it far enough from the 1850 start of the data area as well as from the stack pointer. 1851 1852Please note that the environment is read-only as long as the monitor 1853has been relocated to RAM and a RAM copy of the environment has been 1854created; also, when using EEPROM you will have to use getenv_r() 1855until then to read environment variables. 1856 1857The environment is protected by a CRC32 checksum. Before the monitor 1858is relocated into RAM, as a result of a bad CRC you will be working 1859with the compiled-in default environment - *silently*!!! [This is 1860necessary, because the first environment variable we need is the 1861"baudrate" setting for the console - if we have a bad CRC, we don't 1862have any device yet where we could complain.] 1863 1864Note: once the monitor has been relocated, then it will complain if 1865the default environment is used; a new CRC is computed as soon as you 1866use the "saveenv" command to store a valid environment. 1867 1868- CFG_FAULT_ECHO_LINK_DOWN: 1869 Echo the inverted Ethernet link state to the fault LED. 1870 1871 Note: If this option is active, then CFG_FAULT_MII_ADDR 1872 also needs to be defined. 1873 1874- CFG_FAULT_MII_ADDR: 1875 MII address of the PHY to check for the Ethernet link state. 1876 1877- CFG_64BIT_VSPRINTF: 1878 Makes vsprintf (and all *printf functions) support printing 1879 of 64bit values by using the L quantifier 1880 1881- CFG_64BIT_STRTOUL: 1882 Adds simple_strtoull that returns a 64bit value 1883 1884Low Level (hardware related) configuration options: 1885--------------------------------------------------- 1886 1887- CFG_CACHELINE_SIZE: 1888 Cache Line Size of the CPU. 1889 1890- CFG_DEFAULT_IMMR: 1891 Default address of the IMMR after system reset. 1892 1893 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1894 and RPXsuper) to be able to adjust the position of 1895 the IMMR register after a reset. 1896 1897- Floppy Disk Support: 1898 CFG_FDC_DRIVE_NUMBER 1899 1900 the default drive number (default value 0) 1901 1902 CFG_ISA_IO_STRIDE 1903 1904 defines the spacing between fdc chipset registers 1905 (default value 1) 1906 1907 CFG_ISA_IO_OFFSET 1908 1909 defines the offset of register from address. It 1910 depends on which part of the data bus is connected to 1911 the fdc chipset. (default value 0) 1912 1913 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1914 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1915 default value. 1916 1917 if CFG_FDC_HW_INIT is defined, then the function 1918 fdc_hw_init() is called at the beginning of the FDC 1919 setup. fdc_hw_init() must be provided by the board 1920 source code. It is used to make hardware dependant 1921 initializations. 1922 1923- CFG_IMMR: Physical address of the Internal Memory Mapped 1924 Register; DO NOT CHANGE! (11-4) 1925 [MPC8xx systems only] 1926 1927- CFG_INIT_RAM_ADDR: 1928 1929 Start address of memory area that can be used for 1930 initial data and stack; please note that this must be 1931 writable memory that is working WITHOUT special 1932 initialization, i. e. you CANNOT use normal RAM which 1933 will become available only after programming the 1934 memory controller and running certain initialization 1935 sequences. 1936 1937 U-Boot uses the following memory types: 1938 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1939 - MPC824X: data cache 1940 - PPC4xx: data cache 1941 1942- CFG_GBL_DATA_OFFSET: 1943 1944 Offset of the initial data structure in the memory 1945 area defined by CFG_INIT_RAM_ADDR. Usually 1946 CFG_GBL_DATA_OFFSET is chosen such that the initial 1947 data is located at the end of the available space 1948 (sometimes written as (CFG_INIT_RAM_END - 1949 CFG_INIT_DATA_SIZE), and the initial stack is just 1950 below that area (growing from (CFG_INIT_RAM_ADDR + 1951 CFG_GBL_DATA_OFFSET) downward. 1952 1953 Note: 1954 On the MPC824X (or other systems that use the data 1955 cache for initial memory) the address chosen for 1956 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1957 point to an otherwise UNUSED address space between 1958 the top of RAM and the start of the PCI space. 1959 1960- CFG_SIUMCR: SIU Module Configuration (11-6) 1961 1962- CFG_SYPCR: System Protection Control (11-9) 1963 1964- CFG_TBSCR: Time Base Status and Control (11-26) 1965 1966- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1967 1968- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1969 1970- CFG_SCCR: System Clock and reset Control Register (15-27) 1971 1972- CFG_OR_TIMING_SDRAM: 1973 SDRAM timing 1974 1975- CFG_MAMR_PTA: 1976 periodic timer for refresh 1977 1978- CFG_DER: Debug Event Register (37-47) 1979 1980- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1981 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1982 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1983 CFG_BR1_PRELIM: 1984 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1985 1986- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1987 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1988 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1989 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1990 1991- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1992 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1993 Machine Mode Register and Memory Periodic Timer 1994 Prescaler definitions (SDRAM timing) 1995 1996- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1997 enable I2C microcode relocation patch (MPC8xx); 1998 define relocation offset in DPRAM [DSP2] 1999 2000- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 2001 enable SPI microcode relocation patch (MPC8xx); 2002 define relocation offset in DPRAM [SCC4] 2003 2004- CFG_USE_OSCCLK: 2005 Use OSCM clock mode on MBX8xx board. Be careful, 2006 wrong setting might damage your board. Read 2007 doc/README.MBX before setting this variable! 2008 2009- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 2010 Offset of the bootmode word in DPRAM used by post 2011 (Power On Self Tests). This definition overrides 2012 #define'd default value in commproc.h resp. 2013 cpm_8260.h. 2014 2015- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 2016 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 2017 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 2018 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 2019 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 2020 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 2021 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 2022 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 2023 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 2024 2025- CONFIG_ETHER_ON_FEC[12] 2026 Define to enable FEC[12] on a 8xx series processor. 2027 2028- CONFIG_FEC[12]_PHY 2029 Define to the hardcoded PHY address which corresponds 2030 to the given FEC; i. e. 2031 #define CONFIG_FEC1_PHY 4 2032 means that the PHY with address 4 is connected to FEC1 2033 2034 When set to -1, means to probe for first available. 2035 2036- CONFIG_FEC[12]_PHY_NORXERR 2037 The PHY does not have a RXERR line (RMII only). 2038 (so program the FEC to ignore it). 2039 2040- CONFIG_RMII 2041 Enable RMII mode for all FECs. 2042 Note that this is a global option, we can't 2043 have one FEC in standard MII mode and another in RMII mode. 2044 2045- CONFIG_CRC32_VERIFY 2046 Add a verify option to the crc32 command. 2047 The syntax is: 2048 2049 => crc32 -v <address> <count> <crc32> 2050 2051 Where address/count indicate a memory area 2052 and crc32 is the correct crc32 which the 2053 area should have. 2054 2055Building the Software: 2056====================== 2057 2058Building U-Boot has been tested in native PPC environments (on a 2059PowerBook G3 running LinuxPPC 2000) and in cross environments 2060(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2061NetBSD 1.5 on x86). 2062 2063If you are not using a native PPC environment, it is assumed that you 2064have the GNU cross compiling tools available in your path and named 2065with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2066you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2067the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2068change it to: 2069 2070 CROSS_COMPILE = ppc_4xx- 2071 2072 2073U-Boot is intended to be simple to build. After installing the 2074sources you must configure U-Boot for one specific board type. This 2075is done by typing: 2076 2077 make NAME_config 2078 2079where "NAME_config" is the name of one of the existing 2080configurations; the following names are supported: 2081 2082 ADCIOP_config FPS860L_config omap730p2_config 2083 ADS860_config GEN860T_config pcu_e_config 2084 AR405_config GENIETV_config PIP405_config 2085 at91rm9200dk_config GTH_config QS823_config 2086 CANBT_config hermes_config QS850_config 2087 cmi_mpc5xx_config hymod_config QS860T_config 2088 cogent_common_config IP860_config RPXlite_config 2089 cogent_mpc8260_config IVML24_config RPXlite_DW_config 2090 cogent_mpc8xx_config IVMS8_config RPXsuper_config 2091 CPCI405_config JSE_config rsdproto_config 2092 CPCIISER4_config LANTEC_config Sandpoint8240_config 2093 csb272_config lwmon_config sbc8260_config 2094 CU824_config MBX860T_config sbc8560_33_config 2095 DUET_ADS_config MBX_config sbc8560_66_config 2096 EBONY_config MPC8260ADS_config SM850_config 2097 ELPT860_config MPC8540ADS_config SPD823TS_config 2098 ESTEEM192E_config MPC8560ADS_config stxgp3_config 2099 ETX094_config NETVIA_config SXNI855T_config 2100 FADS823_config omap1510inn_config TQM823L_config 2101 FADS850SAR_config omap1610h2_config TQM850L_config 2102 FADS860T_config omap1610inn_config TQM855L_config 2103 FPS850L_config omap5912osk_config TQM860L_config 2104 WALNUT405_config 2105 ZPC1900_config 2106 2107Note: for some board special configuration names may exist; check if 2108 additional information is available from the board vendor; for 2109 instance, the TQM823L systems are available without (standard) 2110 or with LCD support. You can select such additional "features" 2111 when chosing the configuration, i. e. 2112 2113 make TQM823L_config 2114 - will configure for a plain TQM823L, i. e. no LCD support 2115 2116 make TQM823L_LCD_config 2117 - will configure for a TQM823L with U-Boot console on LCD 2118 2119 etc. 2120 2121 2122Finally, type "make all", and you should get some working U-Boot 2123images ready for download to / installation on your system: 2124 2125- "u-boot.bin" is a raw binary image 2126- "u-boot" is an image in ELF binary format 2127- "u-boot.srec" is in Motorola S-Record format 2128 2129 2130Please be aware that the Makefiles assume you are using GNU make, so 2131for instance on NetBSD you might need to use "gmake" instead of 2132native "make". 2133 2134 2135If the system board that you have is not listed, then you will need 2136to port U-Boot to your hardware platform. To do this, follow these 2137steps: 2138 21391. Add a new configuration option for your board to the toplevel 2140 "Makefile" and to the "MAKEALL" script, using the existing 2141 entries as examples. Note that here and at many other places 2142 boards and other names are listed in alphabetical sort order. Please 2143 keep this order. 21442. Create a new directory to hold your board specific code. Add any 2145 files you need. In your board directory, you will need at least 2146 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 21473. Create a new configuration file "include/configs/<board>.h" for 2148 your board 21493. If you're porting U-Boot to a new CPU, then also create a new 2150 directory to hold your CPU specific code. Add any files you need. 21514. Run "make <board>_config" with your new name. 21525. Type "make", and you should get a working "u-boot.srec" file 2153 to be installed on your target system. 21546. Debug and solve any problems that might arise. 2155 [Of course, this last step is much harder than it sounds.] 2156 2157 2158Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2159============================================================== 2160 2161If you have modified U-Boot sources (for instance added a new board 2162or support for new devices, a new CPU, etc.) you are expected to 2163provide feedback to the other developers. The feedback normally takes 2164the form of a "patch", i. e. a context diff against a certain (latest 2165official or latest in CVS) version of U-Boot sources. 2166 2167But before you submit such a patch, please verify that your modifi- 2168cation did not break existing code. At least make sure that *ALL* of 2169the supported boards compile WITHOUT ANY compiler warnings. To do so, 2170just run the "MAKEALL" script, which will configure and build U-Boot 2171for ALL supported system. Be warned, this will take a while. You can 2172select which (cross) compiler to use by passing a `CROSS_COMPILE' 2173environment variable to the script, i. e. to use the cross tools from 2174MontaVista's Hard Hat Linux you can type 2175 2176 CROSS_COMPILE=ppc_8xx- MAKEALL 2177 2178or to build on a native PowerPC system you can type 2179 2180 CROSS_COMPILE=' ' MAKEALL 2181 2182See also "U-Boot Porting Guide" below. 2183 2184 2185Monitor Commands - Overview: 2186============================ 2187 2188go - start application at address 'addr' 2189run - run commands in an environment variable 2190bootm - boot application image from memory 2191bootp - boot image via network using BootP/TFTP protocol 2192tftpboot- boot image via network using TFTP protocol 2193 and env variables "ipaddr" and "serverip" 2194 (and eventually "gatewayip") 2195rarpboot- boot image via network using RARP/TFTP protocol 2196diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2197loads - load S-Record file over serial line 2198loadb - load binary file over serial line (kermit mode) 2199md - memory display 2200mm - memory modify (auto-incrementing) 2201nm - memory modify (constant address) 2202mw - memory write (fill) 2203cp - memory copy 2204cmp - memory compare 2205crc32 - checksum calculation 2206imd - i2c memory display 2207imm - i2c memory modify (auto-incrementing) 2208inm - i2c memory modify (constant address) 2209imw - i2c memory write (fill) 2210icrc32 - i2c checksum calculation 2211iprobe - probe to discover valid I2C chip addresses 2212iloop - infinite loop on address range 2213isdram - print SDRAM configuration information 2214sspi - SPI utility commands 2215base - print or set address offset 2216printenv- print environment variables 2217setenv - set environment variables 2218saveenv - save environment variables to persistent storage 2219protect - enable or disable FLASH write protection 2220erase - erase FLASH memory 2221flinfo - print FLASH memory information 2222bdinfo - print Board Info structure 2223iminfo - print header information for application image 2224coninfo - print console devices and informations 2225ide - IDE sub-system 2226loop - infinite loop on address range 2227mtest - simple RAM test 2228icache - enable or disable instruction cache 2229dcache - enable or disable data cache 2230reset - Perform RESET of the CPU 2231echo - echo args to console 2232version - print monitor version 2233help - print online help 2234? - alias for 'help' 2235 2236 2237Monitor Commands - Detailed Description: 2238======================================== 2239 2240TODO. 2241 2242For now: just type "help <command>". 2243 2244 2245Environment Variables: 2246====================== 2247 2248U-Boot supports user configuration using Environment Variables which 2249can be made persistent by saving to Flash memory. 2250 2251Environment Variables are set using "setenv", printed using 2252"printenv", and saved to Flash using "saveenv". Using "setenv" 2253without a value can be used to delete a variable from the 2254environment. As long as you don't save the environment you are 2255working with an in-memory copy. In case the Flash area containing the 2256environment is erased by accident, a default environment is provided. 2257 2258Some configuration options can be set using Environment Variables: 2259 2260 baudrate - see CONFIG_BAUDRATE 2261 2262 bootdelay - see CONFIG_BOOTDELAY 2263 2264 bootcmd - see CONFIG_BOOTCOMMAND 2265 2266 bootargs - Boot arguments when booting an RTOS image 2267 2268 bootfile - Name of the image to load with TFTP 2269 2270 autoload - if set to "no" (any string beginning with 'n'), 2271 "bootp" will just load perform a lookup of the 2272 configuration from the BOOTP server, but not try to 2273 load any image using TFTP 2274 2275 autostart - if set to "yes", an image loaded using the "bootp", 2276 "rarpboot", "tftpboot" or "diskboot" commands will 2277 be automatically started (by internally calling 2278 "bootm") 2279 2280 If set to "no", a standalone image passed to the 2281 "bootm" command will be copied to the load address 2282 (and eventually uncompressed), but NOT be started. 2283 This can be used to load and uncompress arbitrary 2284 data. 2285 2286 i2cfast - (PPC405GP|PPC405EP only) 2287 if set to 'y' configures Linux I2C driver for fast 2288 mode (400kHZ). This environment variable is used in 2289 initialization code. So, for changes to be effective 2290 it must be saved and board must be reset. 2291 2292 initrd_high - restrict positioning of initrd images: 2293 If this variable is not set, initrd images will be 2294 copied to the highest possible address in RAM; this 2295 is usually what you want since it allows for 2296 maximum initrd size. If for some reason you want to 2297 make sure that the initrd image is loaded below the 2298 CFG_BOOTMAPSZ limit, you can set this environment 2299 variable to a value of "no" or "off" or "0". 2300 Alternatively, you can set it to a maximum upper 2301 address to use (U-Boot will still check that it 2302 does not overwrite the U-Boot stack and data). 2303 2304 For instance, when you have a system with 16 MB 2305 RAM, and want to reserve 4 MB from use by Linux, 2306 you can do this by adding "mem=12M" to the value of 2307 the "bootargs" variable. However, now you must make 2308 sure that the initrd image is placed in the first 2309 12 MB as well - this can be done with 2310 2311 setenv initrd_high 00c00000 2312 2313 If you set initrd_high to 0xFFFFFFFF, this is an 2314 indication to U-Boot that all addresses are legal 2315 for the Linux kernel, including addresses in flash 2316 memory. In this case U-Boot will NOT COPY the 2317 ramdisk at all. This may be useful to reduce the 2318 boot time on your system, but requires that this 2319 feature is supported by your Linux kernel. 2320 2321 ipaddr - IP address; needed for tftpboot command 2322 2323 loadaddr - Default load address for commands like "bootp", 2324 "rarpboot", "tftpboot", "loadb" or "diskboot" 2325 2326 loads_echo - see CONFIG_LOADS_ECHO 2327 2328 serverip - TFTP server IP address; needed for tftpboot command 2329 2330 bootretry - see CONFIG_BOOT_RETRY_TIME 2331 2332 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2333 2334 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2335 2336 ethprime - When CONFIG_NET_MULTI is enabled controls which 2337 interface is used first. 2338 2339 ethact - When CONFIG_NET_MULTI is enabled controls which 2340 interface is currently active. For example you 2341 can do the following 2342 2343 => setenv ethact FEC ETHERNET 2344 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2345 => setenv ethact SCC ETHERNET 2346 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2347 2348 netretry - When set to "no" each network operation will 2349 either succeed or fail without retrying. 2350 When set to "once" the network operation will 2351 fail when all the available network interfaces 2352 are tried once without success. 2353 Useful on scripts which control the retry operation 2354 themselves. 2355 2356 vlan - When set to a value < 4095 the traffic over 2357 ethernet is encapsulated/received over 802.1q 2358 VLAN tagged frames. 2359 2360The following environment variables may be used and automatically 2361updated by the network boot commands ("bootp" and "rarpboot"), 2362depending the information provided by your boot server: 2363 2364 bootfile - see above 2365 dnsip - IP address of your Domain Name Server 2366 dnsip2 - IP address of your secondary Domain Name Server 2367 gatewayip - IP address of the Gateway (Router) to use 2368 hostname - Target hostname 2369 ipaddr - see above 2370 netmask - Subnet Mask 2371 rootpath - Pathname of the root filesystem on the NFS server 2372 serverip - see above 2373 2374 2375There are two special Environment Variables: 2376 2377 serial# - contains hardware identification information such 2378 as type string and/or serial number 2379 ethaddr - Ethernet address 2380 2381These variables can be set only once (usually during manufacturing of 2382the board). U-Boot refuses to delete or overwrite these variables 2383once they have been set once. 2384 2385 2386Further special Environment Variables: 2387 2388 ver - Contains the U-Boot version string as printed 2389 with the "version" command. This variable is 2390 readonly (see CONFIG_VERSION_VARIABLE). 2391 2392 2393Please note that changes to some configuration parameters may take 2394only effect after the next boot (yes, that's just like Windoze :-). 2395 2396 2397Command Line Parsing: 2398===================== 2399 2400There are two different command line parsers available with U-Boot: 2401the old "simple" one, and the much more powerful "hush" shell: 2402 2403Old, simple command line parser: 2404-------------------------------- 2405 2406- supports environment variables (through setenv / saveenv commands) 2407- several commands on one line, separated by ';' 2408- variable substitution using "... $(name) ..." syntax 2409- special characters ('$', ';') can be escaped by prefixing with '\', 2410 for example: 2411 setenv bootcmd bootm \$(address) 2412- You can also escape text by enclosing in single apostrophes, for example: 2413 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2414 2415Hush shell: 2416----------- 2417 2418- similar to Bourne shell, with control structures like 2419 if...then...else...fi, for...do...done; while...do...done, 2420 until...do...done, ... 2421- supports environment ("global") variables (through setenv / saveenv 2422 commands) and local shell variables (through standard shell syntax 2423 "name=value"); only environment variables can be used with "run" 2424 command 2425 2426General rules: 2427-------------- 2428 2429(1) If a command line (or an environment variable executed by a "run" 2430 command) contains several commands separated by semicolon, and 2431 one of these commands fails, then the remaining commands will be 2432 executed anyway. 2433 2434(2) If you execute several variables with one call to run (i. e. 2435 calling run with a list af variables as arguments), any failing 2436 command will cause "run" to terminate, i. e. the remaining 2437 variables are not executed. 2438 2439Note for Redundant Ethernet Interfaces: 2440======================================= 2441 2442Some boards come with redundant ethernet interfaces; U-Boot supports 2443such configurations and is capable of automatic selection of a 2444"working" interface when needed. MAC assignment works as follows: 2445 2446Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2447MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2448"eth1addr" (=>eth1), "eth2addr", ... 2449 2450If the network interface stores some valid MAC address (for instance 2451in SROM), this is used as default address if there is NO correspon- 2452ding setting in the environment; if the corresponding environment 2453variable is set, this overrides the settings in the card; that means: 2454 2455o If the SROM has a valid MAC address, and there is no address in the 2456 environment, the SROM's address is used. 2457 2458o If there is no valid address in the SROM, and a definition in the 2459 environment exists, then the value from the environment variable is 2460 used. 2461 2462o If both the SROM and the environment contain a MAC address, and 2463 both addresses are the same, this MAC address is used. 2464 2465o If both the SROM and the environment contain a MAC address, and the 2466 addresses differ, the value from the environment is used and a 2467 warning is printed. 2468 2469o If neither SROM nor the environment contain a MAC address, an error 2470 is raised. 2471 2472 2473Image Formats: 2474============== 2475 2476The "boot" commands of this monitor operate on "image" files which 2477can be basicly anything, preceeded by a special header; see the 2478definitions in include/image.h for details; basicly, the header 2479defines the following image properties: 2480 2481* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2482 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2483 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2484 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2485* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2486 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2487 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC). 2488* Compression Type (uncompressed, gzip, bzip2) 2489* Load Address 2490* Entry Point 2491* Image Name 2492* Image Timestamp 2493 2494The header is marked by a special Magic Number, and both the header 2495and the data portions of the image are secured against corruption by 2496CRC32 checksums. 2497 2498 2499Linux Support: 2500============== 2501 2502Although U-Boot should support any OS or standalone application 2503easily, the main focus has always been on Linux during the design of 2504U-Boot. 2505 2506U-Boot includes many features that so far have been part of some 2507special "boot loader" code within the Linux kernel. Also, any 2508"initrd" images to be used are no longer part of one big Linux image; 2509instead, kernel and "initrd" are separate images. This implementation 2510serves several purposes: 2511 2512- the same features can be used for other OS or standalone 2513 applications (for instance: using compressed images to reduce the 2514 Flash memory footprint) 2515 2516- it becomes much easier to port new Linux kernel versions because 2517 lots of low-level, hardware dependent stuff are done by U-Boot 2518 2519- the same Linux kernel image can now be used with different "initrd" 2520 images; of course this also means that different kernel images can 2521 be run with the same "initrd". This makes testing easier (you don't 2522 have to build a new "zImage.initrd" Linux image when you just 2523 change a file in your "initrd"). Also, a field-upgrade of the 2524 software is easier now. 2525 2526 2527Linux HOWTO: 2528============ 2529 2530Porting Linux to U-Boot based systems: 2531--------------------------------------- 2532 2533U-Boot cannot save you from doing all the necessary modifications to 2534configure the Linux device drivers for use with your target hardware 2535(no, we don't intend to provide a full virtual machine interface to 2536Linux :-). 2537 2538But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2539 2540Just make sure your machine specific header file (for instance 2541include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2542Information structure as we define in include/u-boot.h, and make 2543sure that your definition of IMAP_ADDR uses the same value as your 2544U-Boot configuration in CFG_IMMR. 2545 2546 2547Configuring the Linux kernel: 2548----------------------------- 2549 2550No specific requirements for U-Boot. Make sure you have some root 2551device (initial ramdisk, NFS) for your target system. 2552 2553 2554Building a Linux Image: 2555----------------------- 2556 2557With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2558not used. If you use recent kernel source, a new build target 2559"uImage" will exist which automatically builds an image usable by 2560U-Boot. Most older kernels also have support for a "pImage" target, 2561which was introduced for our predecessor project PPCBoot and uses a 2562100% compatible format. 2563 2564Example: 2565 2566 make TQM850L_config 2567 make oldconfig 2568 make dep 2569 make uImage 2570 2571The "uImage" build target uses a special tool (in 'tools/mkimage') to 2572encapsulate a compressed Linux kernel image with header information, 2573CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2574 2575* build a standard "vmlinux" kernel image (in ELF binary format): 2576 2577* convert the kernel into a raw binary image: 2578 2579 ${CROSS_COMPILE}-objcopy -O binary \ 2580 -R .note -R .comment \ 2581 -S vmlinux linux.bin 2582 2583* compress the binary image: 2584 2585 gzip -9 linux.bin 2586 2587* package compressed binary image for U-Boot: 2588 2589 mkimage -A ppc -O linux -T kernel -C gzip \ 2590 -a 0 -e 0 -n "Linux Kernel Image" \ 2591 -d linux.bin.gz uImage 2592 2593 2594The "mkimage" tool can also be used to create ramdisk images for use 2595with U-Boot, either separated from the Linux kernel image, or 2596combined into one file. "mkimage" encapsulates the images with a 64 2597byte header containing information about target architecture, 2598operating system, image type, compression method, entry points, time 2599stamp, CRC32 checksums, etc. 2600 2601"mkimage" can be called in two ways: to verify existing images and 2602print the header information, or to build new images. 2603 2604In the first form (with "-l" option) mkimage lists the information 2605contained in the header of an existing U-Boot image; this includes 2606checksum verification: 2607 2608 tools/mkimage -l image 2609 -l ==> list image header information 2610 2611The second form (with "-d" option) is used to build a U-Boot image 2612from a "data file" which is used as image payload: 2613 2614 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2615 -n name -d data_file image 2616 -A ==> set architecture to 'arch' 2617 -O ==> set operating system to 'os' 2618 -T ==> set image type to 'type' 2619 -C ==> set compression type 'comp' 2620 -a ==> set load address to 'addr' (hex) 2621 -e ==> set entry point to 'ep' (hex) 2622 -n ==> set image name to 'name' 2623 -d ==> use image data from 'datafile' 2624 2625Right now, all Linux kernels for PowerPC systems use the same load 2626address (0x00000000), but the entry point address depends on the 2627kernel version: 2628 2629- 2.2.x kernels have the entry point at 0x0000000C, 2630- 2.3.x and later kernels have the entry point at 0x00000000. 2631 2632So a typical call to build a U-Boot image would read: 2633 2634 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2635 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2636 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2637 > examples/uImage.TQM850L 2638 Image Name: 2.4.4 kernel for TQM850L 2639 Created: Wed Jul 19 02:34:59 2000 2640 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2641 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2642 Load Address: 0x00000000 2643 Entry Point: 0x00000000 2644 2645To verify the contents of the image (or check for corruption): 2646 2647 -> tools/mkimage -l examples/uImage.TQM850L 2648 Image Name: 2.4.4 kernel for TQM850L 2649 Created: Wed Jul 19 02:34:59 2000 2650 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2651 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2652 Load Address: 0x00000000 2653 Entry Point: 0x00000000 2654 2655NOTE: for embedded systems where boot time is critical you can trade 2656speed for memory and install an UNCOMPRESSED image instead: this 2657needs more space in Flash, but boots much faster since it does not 2658need to be uncompressed: 2659 2660 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2661 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2662 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2663 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2664 > examples/uImage.TQM850L-uncompressed 2665 Image Name: 2.4.4 kernel for TQM850L 2666 Created: Wed Jul 19 02:34:59 2000 2667 Image Type: PowerPC Linux Kernel Image (uncompressed) 2668 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2669 Load Address: 0x00000000 2670 Entry Point: 0x00000000 2671 2672 2673Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2674when your kernel is intended to use an initial ramdisk: 2675 2676 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2677 > -A ppc -O linux -T ramdisk -C gzip \ 2678 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2679 Image Name: Simple Ramdisk Image 2680 Created: Wed Jan 12 14:01:50 2000 2681 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2682 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2683 Load Address: 0x00000000 2684 Entry Point: 0x00000000 2685 2686 2687Installing a Linux Image: 2688------------------------- 2689 2690To downloading a U-Boot image over the serial (console) interface, 2691you must convert the image to S-Record format: 2692 2693 objcopy -I binary -O srec examples/image examples/image.srec 2694 2695The 'objcopy' does not understand the information in the U-Boot 2696image header, so the resulting S-Record file will be relative to 2697address 0x00000000. To load it to a given address, you need to 2698specify the target address as 'offset' parameter with the 'loads' 2699command. 2700 2701Example: install the image to address 0x40100000 (which on the 2702TQM8xxL is in the first Flash bank): 2703 2704 => erase 40100000 401FFFFF 2705 2706 .......... done 2707 Erased 8 sectors 2708 2709 => loads 40100000 2710 ## Ready for S-Record download ... 2711 ~>examples/image.srec 2712 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2713 ... 2714 15989 15990 15991 15992 2715 [file transfer complete] 2716 [connected] 2717 ## Start Addr = 0x00000000 2718 2719 2720You can check the success of the download using the 'iminfo' command; 2721this includes a checksum verification so you can be sure no data 2722corruption happened: 2723 2724 => imi 40100000 2725 2726 ## Checking Image at 40100000 ... 2727 Image Name: 2.2.13 for initrd on TQM850L 2728 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2729 Data Size: 335725 Bytes = 327 kB = 0 MB 2730 Load Address: 00000000 2731 Entry Point: 0000000c 2732 Verifying Checksum ... OK 2733 2734 2735Boot Linux: 2736----------- 2737 2738The "bootm" command is used to boot an application that is stored in 2739memory (RAM or Flash). In case of a Linux kernel image, the contents 2740of the "bootargs" environment variable is passed to the kernel as 2741parameters. You can check and modify this variable using the 2742"printenv" and "setenv" commands: 2743 2744 2745 => printenv bootargs 2746 bootargs=root=/dev/ram 2747 2748 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2749 2750 => printenv bootargs 2751 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2752 2753 => bootm 40020000 2754 ## Booting Linux kernel at 40020000 ... 2755 Image Name: 2.2.13 for NFS on TQM850L 2756 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2757 Data Size: 381681 Bytes = 372 kB = 0 MB 2758 Load Address: 00000000 2759 Entry Point: 0000000c 2760 Verifying Checksum ... OK 2761 Uncompressing Kernel Image ... OK 2762 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 2763 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2764 time_init: decrementer frequency = 187500000/60 2765 Calibrating delay loop... 49.77 BogoMIPS 2766 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2767 ... 2768 2769If you want to boot a Linux kernel with initial ram disk, you pass 2770the memory addresses of both the kernel and the initrd image (PPBCOOT 2771format!) to the "bootm" command: 2772 2773 => imi 40100000 40200000 2774 2775 ## Checking Image at 40100000 ... 2776 Image Name: 2.2.13 for initrd on TQM850L 2777 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2778 Data Size: 335725 Bytes = 327 kB = 0 MB 2779 Load Address: 00000000 2780 Entry Point: 0000000c 2781 Verifying Checksum ... OK 2782 2783 ## Checking Image at 40200000 ... 2784 Image Name: Simple Ramdisk Image 2785 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2786 Data Size: 566530 Bytes = 553 kB = 0 MB 2787 Load Address: 00000000 2788 Entry Point: 00000000 2789 Verifying Checksum ... OK 2790 2791 => bootm 40100000 40200000 2792 ## Booting Linux kernel at 40100000 ... 2793 Image Name: 2.2.13 for initrd on TQM850L 2794 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2795 Data Size: 335725 Bytes = 327 kB = 0 MB 2796 Load Address: 00000000 2797 Entry Point: 0000000c 2798 Verifying Checksum ... OK 2799 Uncompressing Kernel Image ... OK 2800 ## Loading RAMDisk Image at 40200000 ... 2801 Image Name: Simple Ramdisk Image 2802 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2803 Data Size: 566530 Bytes = 553 kB = 0 MB 2804 Load Address: 00000000 2805 Entry Point: 00000000 2806 Verifying Checksum ... OK 2807 Loading Ramdisk ... OK 2808 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 2809 Boot arguments: root=/dev/ram 2810 time_init: decrementer frequency = 187500000/60 2811 Calibrating delay loop... 49.77 BogoMIPS 2812 ... 2813 RAMDISK: Compressed image found at block 0 2814 VFS: Mounted root (ext2 filesystem). 2815 2816 bash# 2817 2818More About U-Boot Image Types: 2819------------------------------ 2820 2821U-Boot supports the following image types: 2822 2823 "Standalone Programs" are directly runnable in the environment 2824 provided by U-Boot; it is expected that (if they behave 2825 well) you can continue to work in U-Boot after return from 2826 the Standalone Program. 2827 "OS Kernel Images" are usually images of some Embedded OS which 2828 will take over control completely. Usually these programs 2829 will install their own set of exception handlers, device 2830 drivers, set up the MMU, etc. - this means, that you cannot 2831 expect to re-enter U-Boot except by resetting the CPU. 2832 "RAMDisk Images" are more or less just data blocks, and their 2833 parameters (address, size) are passed to an OS kernel that is 2834 being started. 2835 "Multi-File Images" contain several images, typically an OS 2836 (Linux) kernel image and one or more data images like 2837 RAMDisks. This construct is useful for instance when you want 2838 to boot over the network using BOOTP etc., where the boot 2839 server provides just a single image file, but you want to get 2840 for instance an OS kernel and a RAMDisk image. 2841 2842 "Multi-File Images" start with a list of image sizes, each 2843 image size (in bytes) specified by an "uint32_t" in network 2844 byte order. This list is terminated by an "(uint32_t)0". 2845 Immediately after the terminating 0 follow the images, one by 2846 one, all aligned on "uint32_t" boundaries (size rounded up to 2847 a multiple of 4 bytes). 2848 2849 "Firmware Images" are binary images containing firmware (like 2850 U-Boot or FPGA images) which usually will be programmed to 2851 flash memory. 2852 2853 "Script files" are command sequences that will be executed by 2854 U-Boot's command interpreter; this feature is especially 2855 useful when you configure U-Boot to use a real shell (hush) 2856 as command interpreter. 2857 2858 2859Standalone HOWTO: 2860================= 2861 2862One of the features of U-Boot is that you can dynamically load and 2863run "standalone" applications, which can use some resources of 2864U-Boot like console I/O functions or interrupt services. 2865 2866Two simple examples are included with the sources: 2867 2868"Hello World" Demo: 2869------------------- 2870 2871'examples/hello_world.c' contains a small "Hello World" Demo 2872application; it is automatically compiled when you build U-Boot. 2873It's configured to run at address 0x00040004, so you can play with it 2874like that: 2875 2876 => loads 2877 ## Ready for S-Record download ... 2878 ~>examples/hello_world.srec 2879 1 2 3 4 5 6 7 8 9 10 11 ... 2880 [file transfer complete] 2881 [connected] 2882 ## Start Addr = 0x00040004 2883 2884 => go 40004 Hello World! This is a test. 2885 ## Starting application at 0x00040004 ... 2886 Hello World 2887 argc = 7 2888 argv[0] = "40004" 2889 argv[1] = "Hello" 2890 argv[2] = "World!" 2891 argv[3] = "This" 2892 argv[4] = "is" 2893 argv[5] = "a" 2894 argv[6] = "test." 2895 argv[7] = "<NULL>" 2896 Hit any key to exit ... 2897 2898 ## Application terminated, rc = 0x0 2899 2900Another example, which demonstrates how to register a CPM interrupt 2901handler with the U-Boot code, can be found in 'examples/timer.c'. 2902Here, a CPM timer is set up to generate an interrupt every second. 2903The interrupt service routine is trivial, just printing a '.' 2904character, but this is just a demo program. The application can be 2905controlled by the following keys: 2906 2907 ? - print current values og the CPM Timer registers 2908 b - enable interrupts and start timer 2909 e - stop timer and disable interrupts 2910 q - quit application 2911 2912 => loads 2913 ## Ready for S-Record download ... 2914 ~>examples/timer.srec 2915 1 2 3 4 5 6 7 8 9 10 11 ... 2916 [file transfer complete] 2917 [connected] 2918 ## Start Addr = 0x00040004 2919 2920 => go 40004 2921 ## Starting application at 0x00040004 ... 2922 TIMERS=0xfff00980 2923 Using timer 1 2924 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2925 2926Hit 'b': 2927 [q, b, e, ?] Set interval 1000000 us 2928 Enabling timer 2929Hit '?': 2930 [q, b, e, ?] ........ 2931 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2932Hit '?': 2933 [q, b, e, ?] . 2934 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2935Hit '?': 2936 [q, b, e, ?] . 2937 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2938Hit '?': 2939 [q, b, e, ?] . 2940 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2941Hit 'e': 2942 [q, b, e, ?] ...Stopping timer 2943Hit 'q': 2944 [q, b, e, ?] ## Application terminated, rc = 0x0 2945 2946 2947Minicom warning: 2948================ 2949 2950Over time, many people have reported problems when trying to use the 2951"minicom" terminal emulation program for serial download. I (wd) 2952consider minicom to be broken, and recommend not to use it. Under 2953Unix, I recommend to use C-Kermit for general purpose use (and 2954especially for kermit binary protocol download ("loadb" command), and 2955use "cu" for S-Record download ("loads" command). 2956 2957Nevertheless, if you absolutely want to use it try adding this 2958configuration to your "File transfer protocols" section: 2959 2960 Name Program Name U/D FullScr IO-Red. Multi 2961 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2962 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2963 2964 2965NetBSD Notes: 2966============= 2967 2968Starting at version 0.9.2, U-Boot supports NetBSD both as host 2969(build U-Boot) and target system (boots NetBSD/mpc8xx). 2970 2971Building requires a cross environment; it is known to work on 2972NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2973need gmake since the Makefiles are not compatible with BSD make). 2974Note that the cross-powerpc package does not install include files; 2975attempting to build U-Boot will fail because <machine/ansi.h> is 2976missing. This file has to be installed and patched manually: 2977 2978 # cd /usr/pkg/cross/powerpc-netbsd/include 2979 # mkdir powerpc 2980 # ln -s powerpc machine 2981 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2982 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2983 2984Native builds *don't* work due to incompatibilities between native 2985and U-Boot include files. 2986 2987Booting assumes that (the first part of) the image booted is a 2988stage-2 loader which in turn loads and then invokes the kernel 2989proper. Loader sources will eventually appear in the NetBSD source 2990tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2991meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2992details. 2993 2994 2995Implementation Internals: 2996========================= 2997 2998The following is not intended to be a complete description of every 2999implementation detail. However, it should help to understand the 3000inner workings of U-Boot and make it easier to port it to custom 3001hardware. 3002 3003 3004Initial Stack, Global Data: 3005--------------------------- 3006 3007The implementation of U-Boot is complicated by the fact that U-Boot 3008starts running out of ROM (flash memory), usually without access to 3009system RAM (because the memory controller is not initialized yet). 3010This means that we don't have writable Data or BSS segments, and BSS 3011is not initialized as zero. To be able to get a C environment working 3012at all, we have to allocate at least a minimal stack. Implementation 3013options for this are defined and restricted by the CPU used: Some CPU 3014models provide on-chip memory (like the IMMR area on MPC8xx and 3015MPC826x processors), on others (parts of) the data cache can be 3016locked as (mis-) used as memory, etc. 3017 3018 Chris Hallinan posted a good summary of these issues to the 3019 u-boot-users mailing list: 3020 3021 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 3022 From: "Chris Hallinan" <clh@net1plus.com> 3023 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 3024 ... 3025 3026 Correct me if I'm wrong, folks, but the way I understand it 3027 is this: Using DCACHE as initial RAM for Stack, etc, does not 3028 require any physical RAM backing up the cache. The cleverness 3029 is that the cache is being used as a temporary supply of 3030 necessary storage before the SDRAM controller is setup. It's 3031 beyond the scope of this list to expain the details, but you 3032 can see how this works by studying the cache architecture and 3033 operation in the architecture and processor-specific manuals. 3034 3035 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3036 is another option for the system designer to use as an 3037 initial stack/ram area prior to SDRAM being available. Either 3038 option should work for you. Using CS 4 should be fine if your 3039 board designers haven't used it for something that would 3040 cause you grief during the initial boot! It is frequently not 3041 used. 3042 3043 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3044 with your processor/board/system design. The default value 3045 you will find in any recent u-boot distribution in 3046 Walnut405.h should work for you. I'd set it to a value larger 3047 than your SDRAM module. If you have a 64MB SDRAM module, set 3048 it above 400_0000. Just make sure your board has no resources 3049 that are supposed to respond to that address! That code in 3050 start.S has been around a while and should work as is when 3051 you get the config right. 3052 3053 -Chris Hallinan 3054 DS4.COM, Inc. 3055 3056It is essential to remember this, since it has some impact on the C 3057code for the initialization procedures: 3058 3059* Initialized global data (data segment) is read-only. Do not attempt 3060 to write it. 3061 3062* Do not use any unitialized global data (or implicitely initialized 3063 as zero data - BSS segment) at all - this is undefined, initiali- 3064 zation is performed later (when relocating to RAM). 3065 3066* Stack space is very limited. Avoid big data buffers or things like 3067 that. 3068 3069Having only the stack as writable memory limits means we cannot use 3070normal global data to share information beween the code. But it 3071turned out that the implementation of U-Boot can be greatly 3072simplified by making a global data structure (gd_t) available to all 3073functions. We could pass a pointer to this data as argument to _all_ 3074functions, but this would bloat the code. Instead we use a feature of 3075the GCC compiler (Global Register Variables) to share the data: we 3076place a pointer (gd) to the global data into a register which we 3077reserve for this purpose. 3078 3079When choosing a register for such a purpose we are restricted by the 3080relevant (E)ABI specifications for the current architecture, and by 3081GCC's implementation. 3082 3083For PowerPC, the following registers have specific use: 3084 R1: stack pointer 3085 R2: TOC pointer 3086 R3-R4: parameter passing and return values 3087 R5-R10: parameter passing 3088 R13: small data area pointer 3089 R30: GOT pointer 3090 R31: frame pointer 3091 3092 (U-Boot also uses R14 as internal GOT pointer.) 3093 3094 ==> U-Boot will use R29 to hold a pointer to the global data 3095 3096 Note: on PPC, we could use a static initializer (since the 3097 address of the global data structure is known at compile time), 3098 but it turned out that reserving a register results in somewhat 3099 smaller code - although the code savings are not that big (on 3100 average for all boards 752 bytes for the whole U-Boot image, 3101 624 text + 127 data). 3102 3103On ARM, the following registers are used: 3104 3105 R0: function argument word/integer result 3106 R1-R3: function argument word 3107 R9: GOT pointer 3108 R10: stack limit (used only if stack checking if enabled) 3109 R11: argument (frame) pointer 3110 R12: temporary workspace 3111 R13: stack pointer 3112 R14: link register 3113 R15: program counter 3114 3115 ==> U-Boot will use R8 to hold a pointer to the global data 3116 3117 3118Memory Management: 3119------------------ 3120 3121U-Boot runs in system state and uses physical addresses, i.e. the 3122MMU is not used either for address mapping nor for memory protection. 3123 3124The available memory is mapped to fixed addresses using the memory 3125controller. In this process, a contiguous block is formed for each 3126memory type (Flash, SDRAM, SRAM), even when it consists of several 3127physical memory banks. 3128 3129U-Boot is installed in the first 128 kB of the first Flash bank (on 3130TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3131booting and sizing and initializing DRAM, the code relocates itself 3132to the upper end of DRAM. Immediately below the U-Boot code some 3133memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3134configuration setting]. Below that, a structure with global Board 3135Info data is placed, followed by the stack (growing downward). 3136 3137Additionally, some exception handler code is copied to the low 8 kB 3138of DRAM (0x00000000 ... 0x00001FFF). 3139 3140So a typical memory configuration with 16 MB of DRAM could look like 3141this: 3142 3143 0x0000 0000 Exception Vector code 3144 : 3145 0x0000 1FFF 3146 0x0000 2000 Free for Application Use 3147 : 3148 : 3149 3150 : 3151 : 3152 0x00FB FF20 Monitor Stack (Growing downward) 3153 0x00FB FFAC Board Info Data and permanent copy of global data 3154 0x00FC 0000 Malloc Arena 3155 : 3156 0x00FD FFFF 3157 0x00FE 0000 RAM Copy of Monitor Code 3158 ... eventually: LCD or video framebuffer 3159 ... eventually: pRAM (Protected RAM - unchanged by reset) 3160 0x00FF FFFF [End of RAM] 3161 3162 3163System Initialization: 3164---------------------- 3165 3166In the reset configuration, U-Boot starts at the reset entry point 3167(on most PowerPC systens at address 0x00000100). Because of the reset 3168configuration for CS0# this is a mirror of the onboard Flash memory. 3169To be able to re-map memory U-Boot then jumps to its link address. 3170To be able to implement the initialization code in C, a (small!) 3171initial stack is set up in the internal Dual Ported RAM (in case CPUs 3172which provide such a feature like MPC8xx or MPC8260), or in a locked 3173part of the data cache. After that, U-Boot initializes the CPU core, 3174the caches and the SIU. 3175 3176Next, all (potentially) available memory banks are mapped using a 3177preliminary mapping. For example, we put them on 512 MB boundaries 3178(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3179on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3180programmed for SDRAM access. Using the temporary configuration, a 3181simple memory test is run that determines the size of the SDRAM 3182banks. 3183 3184When there is more than one SDRAM bank, and the banks are of 3185different size, the largest is mapped first. For equal size, the first 3186bank (CS2#) is mapped first. The first mapping is always for address 31870x00000000, with any additional banks following immediately to create 3188contiguous memory starting from 0. 3189 3190Then, the monitor installs itself at the upper end of the SDRAM area 3191and allocates memory for use by malloc() and for the global Board 3192Info data; also, the exception vector code is copied to the low RAM 3193pages, and the final stack is set up. 3194 3195Only after this relocation will you have a "normal" C environment; 3196until that you are restricted in several ways, mostly because you are 3197running from ROM, and because the code will have to be relocated to a 3198new address in RAM. 3199 3200 3201U-Boot Porting Guide: 3202---------------------- 3203 3204[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3205list, October 2002] 3206 3207 3208int main (int argc, char *argv[]) 3209{ 3210 sighandler_t no_more_time; 3211 3212 signal (SIGALRM, no_more_time); 3213 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3214 3215 if (available_money > available_manpower) { 3216 pay consultant to port U-Boot; 3217 return 0; 3218 } 3219 3220 Download latest U-Boot source; 3221 3222 Subscribe to u-boot-users mailing list; 3223 3224 if (clueless) { 3225 email ("Hi, I am new to U-Boot, how do I get started?"); 3226 } 3227 3228 while (learning) { 3229 Read the README file in the top level directory; 3230 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3231 Read the source, Luke; 3232 } 3233 3234 if (available_money > toLocalCurrency ($2500)) { 3235 Buy a BDI2000; 3236 } else { 3237 Add a lot of aggravation and time; 3238 } 3239 3240 Create your own board support subdirectory; 3241 3242 Create your own board config file; 3243 3244 while (!running) { 3245 do { 3246 Add / modify source code; 3247 } until (compiles); 3248 Debug; 3249 if (clueless) 3250 email ("Hi, I am having problems..."); 3251 } 3252 Send patch file to Wolfgang; 3253 3254 return 0; 3255} 3256 3257void no_more_time (int sig) 3258{ 3259 hire_a_guru(); 3260} 3261 3262 3263Coding Standards: 3264----------------- 3265 3266All contributions to U-Boot should conform to the Linux kernel 3267coding style; see the file "Documentation/CodingStyle" in your Linux 3268kernel source directory. 3269 3270Please note that U-Boot is implemented in C (and to some small parts 3271in Assembler); no C++ is used, so please do not use C++ style 3272comments (//) in your code. 3273 3274Please also stick to the following formatting rules: 3275- remove any trailing white space 3276- use TAB characters for indentation, not spaces 3277- make sure NOT to use DOS '\r\n' line feeds 3278- do not add more than 2 empty lines to source files 3279- do not add trailing empty lines to source files 3280 3281Submissions which do not conform to the standards may be returned 3282with a request to reformat the changes. 3283 3284 3285Submitting Patches: 3286------------------- 3287 3288Since the number of patches for U-Boot is growing, we need to 3289establish some rules. Submissions which do not conform to these rules 3290may be rejected, even when they contain important and valuable stuff. 3291 3292 3293When you send a patch, please include the following information with 3294it: 3295 3296* For bug fixes: a description of the bug and how your patch fixes 3297 this bug. Please try to include a way of demonstrating that the 3298 patch actually fixes something. 3299 3300* For new features: a description of the feature and your 3301 implementation. 3302 3303* A CHANGELOG entry as plaintext (separate from the patch) 3304 3305* For major contributions, your entry to the CREDITS file 3306 3307* When you add support for a new board, don't forget to add this 3308 board to the MAKEALL script, too. 3309 3310* If your patch adds new configuration options, don't forget to 3311 document these in the README file. 3312 3313* The patch itself. If you are accessing the CVS repository use "cvs 3314 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3315 version of diff does not support these options, then get the latest 3316 version of GNU diff. 3317 3318 The current directory when running this command shall be the top 3319 level directory of the U-Boot source tree, or it's parent directory 3320 (i. e. please make sure that your patch includes sufficient 3321 directory information for the affected files). 3322 3323 We accept patches as plain text, MIME attachments or as uuencoded 3324 gzipped text. 3325 3326* If one logical set of modifications affects or creates several 3327 files, all these changes shall be submitted in a SINGLE patch file. 3328 3329* Changesets that contain different, unrelated modifications shall be 3330 submitted as SEPARATE patches, one patch per changeset. 3331 3332 3333Notes: 3334 3335* Before sending the patch, run the MAKEALL script on your patched 3336 source tree and make sure that no errors or warnings are reported 3337 for any of the boards. 3338 3339* Keep your modifications to the necessary minimum: A patch 3340 containing several unrelated changes or arbitrary reformats will be 3341 returned with a request to re-formatting / split it. 3342 3343* If you modify existing code, make sure that your new code does not 3344 add to the memory footprint of the code ;-) Small is beautiful! 3345 When adding new features, these should compile conditionally only 3346 (using #ifdef), and the resulting code with the new feature 3347 disabled must not need more memory than the old code without your 3348 modification. 3349