1# 2# (C) Copyright 2000 - 2004 3# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4# 5# See file CREDITS for list of people who contributed to this 6# project. 7# 8# This program is free software; you can redistribute it and/or 9# modify it under the terms of the GNU General Public License as 10# published by the Free Software Foundation; either version 2 of 11# the License, or (at your option) any later version. 12# 13# This program is distributed in the hope that it will be useful, 14# but WITHOUT ANY WARRANTY; without even the implied warranty of 15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16# GNU General Public License for more details. 17# 18# You should have received a copy of the GNU General Public License 19# along with this program; if not, write to the Free Software 20# Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21# MA 02111-1307 USA 22# 23 24Summary: 25======== 26 27This directory contains the source code for U-Boot, a boot loader for 28Embedded boards based on PowerPC and ARM processors, which can be 29installed in a boot ROM and used to initialize and test the hardware 30or to download and run application code. 31 32The development of U-Boot is closely related to Linux: some parts of 33the source code originate in the Linux source tree, we have some 34header files in common, and special provision has been made to 35support booting of Linux images. 36 37Some attention has been paid to make this software easily 38configurable and extendable. For instance, all monitor commands are 39implemented with the same call interface, so that it's very easy to 40add new commands. Also, instead of permanently adding rarely used 41code (for instance hardware test utilities) to the monitor, you can 42load and run it dynamically. 43 44 45Status: 46======= 47 48In general, all boards for which a configuration option exists in the 49Makefile have been tested to some extent and can be considered 50"working". In fact, many of them are used in production systems. 51 52In case of problems see the CHANGELOG and CREDITS files to find out 53who contributed the specific port. 54 55 56Where to get help: 57================== 58 59In case you have questions about, problems with or contributions for 60U-Boot you should send a message to the U-Boot mailing list at 61<u-boot-users@lists.sourceforge.net>. There is also an archive of 62previous traffic on the mailing list - please search the archive 63before asking FAQ's. Please see 64http://lists.sourceforge.net/lists/listinfo/u-boot-users/ 65 66 67Where we come from: 68=================== 69 70- start from 8xxrom sources 71- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 72- clean up code 73- make it easier to add custom boards 74- make it possible to add other [PowerPC] CPUs 75- extend functions, especially: 76 * Provide extended interface to Linux boot loader 77 * S-Record download 78 * network boot 79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot 80- create ARMBoot project (http://sourceforge.net/projects/armboot) 81- add other CPU families (starting with ARM) 82- create U-Boot project (http://sourceforge.net/projects/u-boot) 83 84 85Names and Spelling: 86=================== 87 88The "official" name of this project is "Das U-Boot". The spelling 89"U-Boot" shall be used in all written text (documentation, comments 90in source files etc.). Example: 91 92 This is the README file for the U-Boot project. 93 94File names etc. shall be based on the string "u-boot". Examples: 95 96 include/asm-ppc/u-boot.h 97 98 #include <asm/u-boot.h> 99 100Variable names, preprocessor constants etc. shall be either based on 101the string "u_boot" or on "U_BOOT". Example: 102 103 U_BOOT_VERSION u_boot_logo 104 IH_OS_U_BOOT u_boot_hush_start 105 106 107Versioning: 108=========== 109 110U-Boot uses a 3 level version number containing a version, a 111sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2", 112sub-version "34", and patchlevel "4". 113 114The patchlevel is used to indicate certain stages of development 115between released versions, i. e. officially released versions of 116U-Boot will always have a patchlevel of "0". 117 118 119Directory Hierarchy: 120==================== 121 122- board Board dependent files 123- common Misc architecture independent functions 124- cpu CPU specific files 125 - 74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 126 - arm720t Files specific to ARM 720 CPUs 127 - arm920t Files specific to ARM 920 CPUs 128 - arm925t Files specific to ARM 925 CPUs 129 - arm926ejs Files specific to ARM 926 CPUs 130 - at91rm9200 Files specific to Atmel AT91RM9200 CPUs 131 - i386 Files specific to i386 CPUs 132 - ixp Files specific to Intel XScale IXP CPUs 133 - mcf52x2 Files specific to Motorola ColdFire MCF52x2 CPUs 134 - mips Files specific to MIPS CPUs 135 - mpc5xx Files specific to Motorola MPC5xx CPUs 136 - mpc5xxx Files specific to Motorola MPC5xxx CPUs 137 - mpc8xx Files specific to Motorola MPC8xx CPUs 138 - mpc824x Files specific to Motorola MPC824x CPUs 139 - mpc8260 Files specific to Motorola MPC8260 CPUs 140 - mpc85xx Files specific to Motorola MPC85xx CPUs 141 - nios Files specific to Altera NIOS CPUs 142 - ppc4xx Files specific to IBM PowerPC 4xx CPUs 143 - pxa Files specific to Intel XScale PXA CPUs 144 - s3c44b0 Files specific to Samsung S3C44B0 CPUs 145 - sa1100 Files specific to Intel StrongARM SA1100 CPUs 146- disk Code for disk drive partition handling 147- doc Documentation (don't expect too much) 148- drivers Commonly used device drivers 149- dtt Digital Thermometer and Thermostat drivers 150- examples Example code for standalone applications, etc. 151- include Header Files 152- lib_arm Files generic to ARM architecture 153- lib_generic Files generic to all architectures 154- lib_i386 Files generic to i386 architecture 155- lib_m68k Files generic to m68k architecture 156- lib_mips Files generic to MIPS architecture 157- lib_nios Files generic to NIOS architecture 158- lib_ppc Files generic to PowerPC architecture 159- net Networking code 160- post Power On Self Test 161- rtc Real Time Clock drivers 162- tools Tools to build S-Record or U-Boot images, etc. 163 164Software Configuration: 165======================= 166 167Configuration is usually done using C preprocessor defines; the 168rationale behind that is to avoid dead code whenever possible. 169 170There are two classes of configuration variables: 171 172* Configuration _OPTIONS_: 173 These are selectable by the user and have names beginning with 174 "CONFIG_". 175 176* Configuration _SETTINGS_: 177 These depend on the hardware etc. and should not be meddled with if 178 you don't know what you're doing; they have names beginning with 179 "CFG_". 180 181Later we will add a configuration tool - probably similar to or even 182identical to what's used for the Linux kernel. Right now, we have to 183do the configuration by hand, which means creating some symbolic 184links and editing some configuration files. We use the TQM8xxL boards 185as an example here. 186 187 188Selection of Processor Architecture and Board Type: 189--------------------------------------------------- 190 191For all supported boards there are ready-to-use default 192configurations available; just type "make <board_name>_config". 193 194Example: For a TQM823L module type: 195 196 cd u-boot 197 make TQM823L_config 198 199For the Cogent platform, you need to specify the cpu type as well; 200e.g. "make cogent_mpc8xx_config". And also configure the cogent 201directory according to the instructions in cogent/README. 202 203 204Configuration Options: 205---------------------- 206 207Configuration depends on the combination of board and CPU type; all 208such information is kept in a configuration file 209"include/configs/<board_name>.h". 210 211Example: For a TQM823L module, all configuration settings are in 212"include/configs/TQM823L.h". 213 214 215Many of the options are named exactly as the corresponding Linux 216kernel configuration options. The intention is to make it easier to 217build a config tool - later. 218 219 220The following options need to be configured: 221 222- CPU Type: Define exactly one of 223 224 PowerPC based CPUs: 225 ------------------- 226 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 227 or CONFIG_MPC5xx 228 or CONFIG_MPC824X, CONFIG_MPC8260 229 or CONFIG_MPC85xx 230 or CONFIG_IOP480 231 or CONFIG_405GP 232 or CONFIG_405EP 233 or CONFIG_440 234 or CONFIG_MPC74xx 235 or CONFIG_750FX 236 237 ARM based CPUs: 238 --------------- 239 CONFIG_SA1110 240 CONFIG_ARM7 241 CONFIG_PXA250 242 243 MicroBlaze based CPUs: 244 ---------------------- 245 CONFIG_MICROBLZE 246 247 248- Board Type: Define exactly one of 249 250 PowerPC based boards: 251 --------------------- 252 253 CONFIG_ADCIOP CONFIG_GEN860T CONFIG_PCI405 254 CONFIG_ADS860 CONFIG_GENIETV CONFIG_PCIPPC2 255 CONFIG_AMX860 CONFIG_GTH CONFIG_PCIPPC6 256 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e 257 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405 258 CONFIG_c2mon CONFIG_hymod CONFIG_PM826 259 CONFIG_CANBT CONFIG_IAD210 CONFIG_ppmc8260 260 CONFIG_CCM CONFIG_ICU862 CONFIG_QS823 261 CONFIG_CMI CONFIG_IP860 CONFIG_QS850 262 CONFIG_cogent_mpc8260 CONFIG_IPHASE4539 CONFIG_QS860T 263 CONFIG_cogent_mpc8xx CONFIG_IVML24 CONFIG_RBC823 264 CONFIG_CPCI405 CONFIG_IVML24_128 CONFIG_RPXClassic 265 CONFIG_CPCI4052 CONFIG_IVML24_256 CONFIG_RPXlite 266 CONFIG_CPCIISER4 CONFIG_IVMS8 CONFIG_RPXsuper 267 CONFIG_CPU86 CONFIG_IVMS8_128 CONFIG_rsdproto 268 CONFIG_CRAYL1 CONFIG_IVMS8_256 CONFIG_sacsng 269 CONFIG_CSB272 CONFIG_JSE CONFIG_Sandpoint8240 270 CONFIG_CU824 CONFIG_LANTEC CONFIG_Sandpoint8245 271 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8260 272 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850 273 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS 274 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3 275 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T 276 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L 277 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260 278 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L 279 CONFIG_ep8260 CONFIG_MPC8560ADS CONFIG_TQM855L 280 CONFIG_ERIC CONFIG_MUSENKI CONFIG_TQM860L 281 CONFIG_ESTEEM192E CONFIG_MVS1 CONFIG_TTTech 282 CONFIG_ETX094 CONFIG_NETPHONE CONFIG_UTX8245 283 CONFIG_EVB64260 CONFIG_NETTA CONFIG_V37 284 CONFIG_FADS823 CONFIG_NETVIA CONFIG_W7OLMC 285 CONFIG_FADS850SAR CONFIG_NX823 CONFIG_W7OLMG 286 CONFIG_FADS860T CONFIG_OCRTC CONFIG_WALNUT405 287 CONFIG_FLAGADM CONFIG_ORSG CONFIG_ZPC1900 288 CONFIG_FPS850L CONFIG_OXC CONFIG_ZUMA 289 CONFIG_FPS860L 290 291 ARM based boards: 292 ----------------- 293 294 CONFIG_AT91RM9200DK, CONFIG_DNP1110, CONFIG_EP7312, 295 CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE, CONFIG_IMPA7, 296 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610, CONFIG_LART, 297 CONFIG_LUBBOCK, CONFIG_SHANNON, CONFIG_P2_OMAP730, 298 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB, 299 CONFIG_VCMA9 300 301 MicroBlaze based boards: 302 ------------------------ 303 304 CONFIG_SUZAKU 305 306 307- CPU Module Type: (if CONFIG_COGENT is defined) 308 Define exactly one of 309 CONFIG_CMA286_60_OLD 310--- FIXME --- not tested yet: 311 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 312 CONFIG_CMA287_23, CONFIG_CMA287_50 313 314- Motherboard Type: (if CONFIG_COGENT is defined) 315 Define exactly one of 316 CONFIG_CMA101, CONFIG_CMA102 317 318- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 319 Define one or more of 320 CONFIG_CMA302 321 322- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 323 Define one or more of 324 CONFIG_LCD_HEARTBEAT - update a character position on 325 the lcd display every second with 326 a "rotator" |\-/|\-/ 327 328- Board flavour: (if CONFIG_MPC8260ADS is defined) 329 CONFIG_ADSTYPE 330 Possible values are: 331 CFG_8260ADS - original MPC8260ADS 332 CFG_8266ADS - MPC8266ADS 333 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR 334 CFG_8272ADS - MPC8272ADS 335 336- MPC824X Family Member (if CONFIG_MPC824X is defined) 337 Define exactly one of 338 CONFIG_MPC8240, CONFIG_MPC8245 339 340- 8xx CPU Options: (if using an MPC8xx cpu) 341 Define one or more of 342 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work 343 e.g. if there is no 32KHz 344 reference PIT/RTC clock 345 346- 859/866 CPU options: (if using a MPC859 or MPC866 CPU): 347 CFG_866_OSCCLK 348 CFG_866_CPUCLK_MIN 349 CFG_866_CPUCLK_MAX 350 CFG_866_CPUCLK_DEFAULT 351 See doc/README.MPC866 352 353 CFG_MEASURE_CPUCLK 354 355 Define this to measure the actual CPU clock instead 356 of relying on the correctness of the configured 357 values. Mostly useful for board bringup to make sure 358 the PLL is locked at the intended frequency. Note 359 that this requires a (stable) reference clock (32 kHz 360 RTC clock), 361 362- Linux Kernel Interface: 363 CONFIG_CLOCKS_IN_MHZ 364 365 U-Boot stores all clock information in Hz 366 internally. For binary compatibility with older Linux 367 kernels (which expect the clocks passed in the 368 bd_info data to be in MHz) the environment variable 369 "clocks_in_mhz" can be defined so that U-Boot 370 converts clock data to MHZ before passing it to the 371 Linux kernel. 372 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 373 "clocks_in_mhz=1" is automatically included in the 374 default environment. 375 376 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 377 378 When transfering memsize parameter to linux, some versions 379 expect it to be in bytes, others in MB. 380 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 381 382- Console Interface: 383 Depending on board, define exactly one serial port 384 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 385 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 386 console by defining CONFIG_8xx_CONS_NONE 387 388 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 389 port routines must be defined elsewhere 390 (i.e. serial_init(), serial_getc(), ...) 391 392 CONFIG_CFB_CONSOLE 393 Enables console device for a color framebuffer. Needs following 394 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 395 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 396 (default big endian) 397 VIDEO_HW_RECTFILL graphic chip supports 398 rectangle fill 399 (cf. smiLynxEM) 400 VIDEO_HW_BITBLT graphic chip supports 401 bit-blit (cf. smiLynxEM) 402 VIDEO_VISIBLE_COLS visible pixel columns 403 (cols=pitch) 404 VIDEO_VISIBLE_ROWS visible pixel rows 405 VIDEO_PIXEL_SIZE bytes per pixel 406 VIDEO_DATA_FORMAT graphic data format 407 (0-5, cf. cfb_console.c) 408 VIDEO_FB_ADRS framebuffer address 409 VIDEO_KBD_INIT_FCT keyboard int fct 410 (i.e. i8042_kbd_init()) 411 VIDEO_TSTC_FCT test char fct 412 (i.e. i8042_tstc) 413 VIDEO_GETC_FCT get char fct 414 (i.e. i8042_getc) 415 CONFIG_CONSOLE_CURSOR cursor drawing on/off 416 (requires blink timer 417 cf. i8042.c) 418 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 419 CONFIG_CONSOLE_TIME display time/date info in 420 upper right corner 421 (requires CFG_CMD_DATE) 422 CONFIG_VIDEO_LOGO display Linux logo in 423 upper left corner 424 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 425 linux_logo.h for logo. 426 Requires CONFIG_VIDEO_LOGO 427 CONFIG_CONSOLE_EXTRA_INFO 428 addional board info beside 429 the logo 430 431 When CONFIG_CFB_CONSOLE is defined, video console is 432 default i/o. Serial console can be forced with 433 environment 'console=serial'. 434 435 When CONFIG_SILENT_CONSOLE is defined, all console 436 messages (by U-Boot and Linux!) can be silenced with 437 the "silent" environment variable. See 438 doc/README.silent for more information. 439 440- Console Baudrate: 441 CONFIG_BAUDRATE - in bps 442 Select one of the baudrates listed in 443 CFG_BAUDRATE_TABLE, see below. 444 CFG_BRGCLK_PRESCALE, baudrate prescale 445 446- Interrupt driven serial port input: 447 CONFIG_SERIAL_SOFTWARE_FIFO 448 449 PPC405GP only. 450 Use an interrupt handler for receiving data on the 451 serial port. It also enables using hardware handshake 452 (RTS/CTS) and UART's built-in FIFO. Set the number of 453 bytes the interrupt driven input buffer should have. 454 455 Leave undefined to disable this feature, including 456 disable the buffer and hardware handshake. 457 458- Console UART Number: 459 CONFIG_UART1_CONSOLE 460 461 IBM PPC4xx only. 462 If defined internal UART1 (and not UART0) is used 463 as default U-Boot console. 464 465- Boot Delay: CONFIG_BOOTDELAY - in seconds 466 Delay before automatically booting the default image; 467 set to -1 to disable autoboot. 468 469 See doc/README.autoboot for these options that 470 work with CONFIG_BOOTDELAY. None are required. 471 CONFIG_BOOT_RETRY_TIME 472 CONFIG_BOOT_RETRY_MIN 473 CONFIG_AUTOBOOT_KEYED 474 CONFIG_AUTOBOOT_PROMPT 475 CONFIG_AUTOBOOT_DELAY_STR 476 CONFIG_AUTOBOOT_STOP_STR 477 CONFIG_AUTOBOOT_DELAY_STR2 478 CONFIG_AUTOBOOT_STOP_STR2 479 CONFIG_ZERO_BOOTDELAY_CHECK 480 CONFIG_RESET_TO_RETRY 481 482- Autoboot Command: 483 CONFIG_BOOTCOMMAND 484 Only needed when CONFIG_BOOTDELAY is enabled; 485 define a command string that is automatically executed 486 when no character is read on the console interface 487 within "Boot Delay" after reset. 488 489 CONFIG_BOOTARGS 490 This can be used to pass arguments to the bootm 491 command. The value of CONFIG_BOOTARGS goes into the 492 environment value "bootargs". 493 494 CONFIG_RAMBOOT and CONFIG_NFSBOOT 495 The value of these goes into the environment as 496 "ramboot" and "nfsboot" respectively, and can be used 497 as a convenience, when switching between booting from 498 ram and nfs. 499 500- Pre-Boot Commands: 501 CONFIG_PREBOOT 502 503 When this option is #defined, the existence of the 504 environment variable "preboot" will be checked 505 immediately before starting the CONFIG_BOOTDELAY 506 countdown and/or running the auto-boot command resp. 507 entering interactive mode. 508 509 This feature is especially useful when "preboot" is 510 automatically generated or modified. For an example 511 see the LWMON board specific code: here "preboot" is 512 modified when the user holds down a certain 513 combination of keys on the (special) keyboard when 514 booting the systems 515 516- Serial Download Echo Mode: 517 CONFIG_LOADS_ECHO 518 If defined to 1, all characters received during a 519 serial download (using the "loads" command) are 520 echoed back. This might be needed by some terminal 521 emulations (like "cu"), but may as well just take 522 time on others. This setting #define's the initial 523 value of the "loads_echo" environment variable. 524 525- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 526 CONFIG_KGDB_BAUDRATE 527 Select one of the baudrates listed in 528 CFG_BAUDRATE_TABLE, see below. 529 530- Monitor Functions: 531 CONFIG_COMMANDS 532 Most monitor functions can be selected (or 533 de-selected) by adjusting the definition of 534 CONFIG_COMMANDS; to select individual functions, 535 #define CONFIG_COMMANDS by "OR"ing any of the 536 following values: 537 538 #define enables commands: 539 ------------------------- 540 CFG_CMD_ASKENV * ask for env variable 541 CFG_CMD_AUTOSCRIPT Autoscript Support 542 CFG_CMD_BDI bdinfo 543 CFG_CMD_BEDBUG Include BedBug Debugger 544 CFG_CMD_BMP * BMP support 545 CFG_CMD_BOOTD bootd 546 CFG_CMD_CACHE icache, dcache 547 CFG_CMD_CONSOLE coninfo 548 CFG_CMD_DATE * support for RTC, date/time... 549 CFG_CMD_DHCP DHCP support 550 CFG_CMD_DIAG * Diagnostics 551 CFG_CMD_DOC * Disk-On-Chip Support 552 CFG_CMD_DTT Digital Therm and Thermostat 553 CFG_CMD_ECHO * echo arguments 554 CFG_CMD_EEPROM * EEPROM read/write support 555 CFG_CMD_ELF bootelf, bootvx 556 CFG_CMD_ENV saveenv 557 CFG_CMD_FDC * Floppy Disk Support 558 CFG_CMD_FAT FAT partition support 559 CFG_CMD_FDOS * Dos diskette Support 560 CFG_CMD_FLASH flinfo, erase, protect 561 CFG_CMD_FPGA FPGA device initialization support 562 CFG_CMD_HWFLOW * RTS/CTS hw flow control 563 CFG_CMD_I2C * I2C serial bus support 564 CFG_CMD_IDE * IDE harddisk support 565 CFG_CMD_IMI iminfo 566 CFG_CMD_IMLS List all found images 567 CFG_CMD_IMMAP * IMMR dump support 568 CFG_CMD_IRQ * irqinfo 569 CFG_CMD_ITEST * Integer/string test of 2 values 570 CFG_CMD_JFFS2 * JFFS2 Support 571 CFG_CMD_KGDB * kgdb 572 CFG_CMD_LOADB loadb 573 CFG_CMD_LOADS loads 574 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 575 loop, mtest 576 CFG_CMD_MISC Misc functions like sleep etc 577 CFG_CMD_MMC MMC memory mapped support 578 CFG_CMD_MII MII utility commands 579 CFG_CMD_NAND * NAND support 580 CFG_CMD_NET bootp, tftpboot, rarpboot 581 CFG_CMD_PCI * pciinfo 582 CFG_CMD_PCMCIA * PCMCIA support 583 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host 584 CFG_CMD_PORTIO * Port I/O 585 CFG_CMD_REGINFO * Register dump 586 CFG_CMD_RUN run command in env variable 587 CFG_CMD_SAVES save S record dump 588 CFG_CMD_SCSI * SCSI Support 589 CFG_CMD_SDRAM * print SDRAM configuration information 590 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 591 CFG_CMD_SPI * SPI serial bus support 592 CFG_CMD_USB * USB support 593 CFG_CMD_VFD * VFD support (TRAB) 594 CFG_CMD_BSP * Board SPecific functions 595 CFG_CMD_CDP * Cisco Discover Protocol support 596 ----------------------------------------------- 597 CFG_CMD_ALL all 598 599 CFG_CMD_DFL Default configuration; at the moment 600 this is includes all commands, except 601 the ones marked with "*" in the list 602 above. 603 604 If you don't define CONFIG_COMMANDS it defaults to 605 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 606 override the default settings in the respective 607 include file. 608 609 EXAMPLE: If you want all functions except of network 610 support you can write: 611 612 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 613 614 615 Note: Don't enable the "icache" and "dcache" commands 616 (configuration option CFG_CMD_CACHE) unless you know 617 what you (and your U-Boot users) are doing. Data 618 cache cannot be enabled on systems like the 8xx or 619 8260 (where accesses to the IMMR region must be 620 uncached), and it cannot be disabled on all other 621 systems where we (mis-) use the data cache to hold an 622 initial stack and some data. 623 624 625 XXX - this list needs to get updated! 626 627- Watchdog: 628 CONFIG_WATCHDOG 629 If this variable is defined, it enables watchdog 630 support. There must be support in the platform specific 631 code for a watchdog. For the 8xx and 8260 CPUs, the 632 SIU Watchdog feature is enabled in the SYPCR 633 register. 634 635- U-Boot Version: 636 CONFIG_VERSION_VARIABLE 637 If this variable is defined, an environment variable 638 named "ver" is created by U-Boot showing the U-Boot 639 version as printed by the "version" command. 640 This variable is readonly. 641 642- Real-Time Clock: 643 644 When CFG_CMD_DATE is selected, the type of the RTC 645 has to be selected, too. Define exactly one of the 646 following options: 647 648 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 649 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 650 CONFIG_RTC_MC146818 - use MC146818 RTC 651 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 652 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 653 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 654 CONFIG_RTC_DS164x - use Dallas DS164x RTC 655 656 Note that if the RTC uses I2C, then the I2C interface 657 must also be configured. See I2C Support, below. 658 659- Timestamp Support: 660 661 When CONFIG_TIMESTAMP is selected, the timestamp 662 (date and time) of an image is printed by image 663 commands like bootm or iminfo. This option is 664 automatically enabled when you select CFG_CMD_DATE . 665 666- Partition Support: 667 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 668 and/or CONFIG_ISO_PARTITION 669 670 If IDE or SCSI support is enabled (CFG_CMD_IDE or 671 CFG_CMD_SCSI) you must configure support for at least 672 one partition type as well. 673 674- IDE Reset method: 675 CONFIG_IDE_RESET_ROUTINE - this is defined in several 676 board configurations files but used nowhere! 677 678 CONFIG_IDE_RESET - is this is defined, IDE Reset will 679 be performed by calling the function 680 ide_set_reset(int reset) 681 which has to be defined in a board specific file 682 683- ATAPI Support: 684 CONFIG_ATAPI 685 686 Set this to enable ATAPI support. 687 688- LBA48 Support 689 CONFIG_LBA48 690 691 Set this to enable support for disks larger than 137GB 692 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 693 Whithout these , LBA48 support uses 32bit variables and will 'only' 694 support disks up to 2.1TB. 695 696 CFG_64BIT_LBA: 697 When enabled, makes the IDE subsystem use 64bit sector addresses. 698 Default is 32bit. 699 700- SCSI Support: 701 At the moment only there is only support for the 702 SYM53C8XX SCSI controller; define 703 CONFIG_SCSI_SYM53C8XX to enable it. 704 705 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 706 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 707 CFG_SCSI_MAX_LUN] can be adjusted to define the 708 maximum numbers of LUNs, SCSI ID's and target 709 devices. 710 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 711 712- NETWORK Support (PCI): 713 CONFIG_E1000 714 Support for Intel 8254x gigabit chips. 715 716 CONFIG_EEPRO100 717 Support for Intel 82557/82559/82559ER chips. 718 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 719 write routine for first time initialisation. 720 721 CONFIG_TULIP 722 Support for Digital 2114x chips. 723 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 724 modem chip initialisation (KS8761/QS6611). 725 726 CONFIG_NATSEMI 727 Support for National dp83815 chips. 728 729 CONFIG_NS8382X 730 Support for National dp8382[01] gigabit chips. 731 732- NETWORK Support (other): 733 734 CONFIG_DRIVER_LAN91C96 735 Support for SMSC's LAN91C96 chips. 736 737 CONFIG_LAN91C96_BASE 738 Define this to hold the physical address 739 of the LAN91C96's I/O space 740 741 CONFIG_LAN91C96_USE_32_BIT 742 Define this to enable 32 bit addressing 743 744- USB Support: 745 At the moment only the UHCI host controller is 746 supported (PIP405, MIP405, MPC5200); define 747 CONFIG_USB_UHCI to enable it. 748 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 749 end define CONFIG_USB_STORAGE to enable the USB 750 storage devices. 751 Note: 752 Supported are USB Keyboards and USB Floppy drives 753 (TEAC FD-05PUB). 754 MPC5200 USB requires additional defines: 755 CONFIG_USB_CLOCK 756 for 528 MHz Clock: 0x0001bbbb 757 CONFIG_USB_CONFIG 758 for differential drivers: 0x00001000 759 for single ended drivers: 0x00005000 760 761 762- MMC Support: 763 The MMC controller on the Intel PXA is supported. To 764 enable this define CONFIG_MMC. The MMC can be 765 accessed from the boot prompt by mapping the device 766 to physical memory similar to flash. Command line is 767 enabled with CFG_CMD_MMC. The MMC driver also works with 768 the FAT fs. This is enabled with CFG_CMD_FAT. 769 770- Keyboard Support: 771 CONFIG_ISA_KEYBOARD 772 773 Define this to enable standard (PC-Style) keyboard 774 support 775 776 CONFIG_I8042_KBD 777 Standard PC keyboard driver with US (is default) and 778 GERMAN key layout (switch via environment 'keymap=de') support. 779 Export function i8042_kbd_init, i8042_tstc and i8042_getc 780 for cfb_console. Supports cursor blinking. 781 782- Video support: 783 CONFIG_VIDEO 784 785 Define this to enable video support (for output to 786 video). 787 788 CONFIG_VIDEO_CT69000 789 790 Enable Chips & Technologies 69000 Video chip 791 792 CONFIG_VIDEO_SMI_LYNXEM 793 Enable Silicon Motion SMI 712/710/810 Video chip. The 794 video output is selected via environment 'videoout' 795 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 796 assumed. 797 798 For the CT69000 and SMI_LYNXEM drivers, videomode is 799 selected via environment 'videomode'. Two diferent ways 800 are possible: 801 - "videomode=num" 'num' is a standard LiLo mode numbers. 802 Following standard modes are supported (* is default): 803 804 Colors 640x480 800x600 1024x768 1152x864 1280x1024 805 -------------+--------------------------------------------- 806 8 bits | 0x301* 0x303 0x305 0x161 0x307 807 15 bits | 0x310 0x313 0x316 0x162 0x319 808 16 bits | 0x311 0x314 0x317 0x163 0x31A 809 24 bits | 0x312 0x315 0x318 ? 0x31B 810 -------------+--------------------------------------------- 811 (i.e. setenv videomode 317; saveenv; reset;) 812 813 - "videomode=bootargs" all the video parameters are parsed 814 from the bootargs. (See drivers/videomodes.c) 815 816 817 CONFIG_VIDEO_SED13806 818 Enable Epson SED13806 driver. This driver supports 8bpp 819 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 820 or CONFIG_VIDEO_SED13806_16BPP 821 822- Keyboard Support: 823 CONFIG_KEYBOARD 824 825 Define this to enable a custom keyboard support. 826 This simply calls drv_keyboard_init() which must be 827 defined in your board-specific files. 828 The only board using this so far is RBC823. 829 830- LCD Support: CONFIG_LCD 831 832 Define this to enable LCD support (for output to LCD 833 display); also select one of the supported displays 834 by defining one of these: 835 836 CONFIG_NEC_NL6448AC33: 837 838 NEC NL6448AC33-18. Active, color, single scan. 839 840 CONFIG_NEC_NL6448BC20 841 842 NEC NL6448BC20-08. 6.5", 640x480. 843 Active, color, single scan. 844 845 CONFIG_NEC_NL6448BC33_54 846 847 NEC NL6448BC33-54. 10.4", 640x480. 848 Active, color, single scan. 849 850 CONFIG_SHARP_16x9 851 852 Sharp 320x240. Active, color, single scan. 853 It isn't 16x9, and I am not sure what it is. 854 855 CONFIG_SHARP_LQ64D341 856 857 Sharp LQ64D341 display, 640x480. 858 Active, color, single scan. 859 860 CONFIG_HLD1045 861 862 HLD1045 display, 640x480. 863 Active, color, single scan. 864 865 CONFIG_OPTREX_BW 866 867 Optrex CBL50840-2 NF-FW 99 22 M5 868 or 869 Hitachi LMG6912RPFC-00T 870 or 871 Hitachi SP14Q002 872 873 320x240. Black & white. 874 875 Normally display is black on white background; define 876 CFG_WHITE_ON_BLACK to get it inverted. 877 878- Splash Screen Support: CONFIG_SPLASH_SCREEN 879 880 If this option is set, the environment is checked for 881 a variable "splashimage". If found, the usual display 882 of logo, copyright and system information on the LCD 883 is supressed and the BMP image at the address 884 specified in "splashimage" is loaded instead. The 885 console is redirected to the "nulldev", too. This 886 allows for a "silent" boot where a splash screen is 887 loaded very quickly after power-on. 888 889- Compression support: 890 CONFIG_BZIP2 891 892 If this option is set, support for bzip2 compressed 893 images is included. If not, only uncompressed and gzip 894 compressed images are supported. 895 896 NOTE: the bzip2 algorithm requires a lot of RAM, so 897 the malloc area (as defined by CFG_MALLOC_LEN) should 898 be at least 4MB. 899 900- MII/PHY support: 901 CONFIG_PHY_ADDR 902 903 The address of PHY on MII bus. 904 905 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 906 907 The clock frequency of the MII bus 908 909 CONFIG_PHY_GIGE 910 911 If this option is set, support for speed/duplex 912 detection of Gigabit PHY is included. 913 914 CONFIG_PHY_RESET_DELAY 915 916 Some PHY like Intel LXT971A need extra delay after 917 reset before any MII register access is possible. 918 For such PHY, set this option to the usec delay 919 required. (minimum 300usec for LXT971A) 920 921 CONFIG_PHY_CMD_DELAY (ppc4xx) 922 923 Some PHY like Intel LXT971A need extra delay after 924 command issued before MII status register can be read 925 926- Ethernet address: 927 CONFIG_ETHADDR 928 CONFIG_ETH2ADDR 929 CONFIG_ETH3ADDR 930 931 Define a default value for ethernet address to use 932 for the respective ethernet interface, in case this 933 is not determined automatically. 934 935- IP address: 936 CONFIG_IPADDR 937 938 Define a default value for the IP address to use for 939 the default ethernet interface, in case this is not 940 determined through e.g. bootp. 941 942- Server IP address: 943 CONFIG_SERVERIP 944 945 Defines a default value for theIP address of a TFTP 946 server to contact when using the "tftboot" command. 947 948- BOOTP Recovery Mode: 949 CONFIG_BOOTP_RANDOM_DELAY 950 951 If you have many targets in a network that try to 952 boot using BOOTP, you may want to avoid that all 953 systems send out BOOTP requests at precisely the same 954 moment (which would happen for instance at recovery 955 from a power failure, when all systems will try to 956 boot, thus flooding the BOOTP server. Defining 957 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 958 inserted before sending out BOOTP requests. The 959 following delays are insterted then: 960 961 1st BOOTP request: delay 0 ... 1 sec 962 2nd BOOTP request: delay 0 ... 2 sec 963 3rd BOOTP request: delay 0 ... 4 sec 964 4th and following 965 BOOTP requests: delay 0 ... 8 sec 966 967- DHCP Advanced Options: 968 CONFIG_BOOTP_MASK 969 970 You can fine tune the DHCP functionality by adding 971 these flags to the CONFIG_BOOTP_MASK define: 972 973 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 974 serverip from a DHCP server, it is possible that more 975 than one DNS serverip is offered to the client. 976 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 977 serverip will be stored in the additional environment 978 variable "dnsip2". The first DNS serverip is always 979 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 980 is added to the CONFIG_BOOTP_MASK. 981 982 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 983 to do a dynamic update of a DNS server. To do this, they 984 need the hostname of the DHCP requester. 985 If CONFIG_BOOP_SEND_HOSTNAME is added to the 986 CONFIG_BOOTP_MASK, the content of the "hostname" 987 environment variable is passed as option 12 to 988 the DHCP server. 989 990 - CDP Options: 991 CONFIG_CDP_DEVICE_ID 992 993 The device id used in CDP trigger frames. 994 995 CONFIG_CDP_DEVICE_ID_PREFIX 996 997 A two character string which is prefixed to the MAC address 998 of the device. 999 1000 CONFIG_CDP_PORT_ID 1001 1002 A printf format string which contains the ascii name of 1003 the port. Normally is set to "eth%d" which sets 1004 eth0 for the first ethernet, eth1 for the second etc. 1005 1006 CONFIG_CDP_CAPABILITIES 1007 1008 A 32bit integer which indicates the device capabilities; 1009 0x00000010 for a normal host which does not forwards. 1010 1011 CONFIG_CDP_VERSION 1012 1013 An ascii string containing the version of the software. 1014 1015 CONFIG_CDP_PLATFORM 1016 1017 An ascii string containing the name of the platform. 1018 1019 CONFIG_CDP_TRIGGER 1020 1021 A 32bit integer sent on the trigger. 1022 1023 CONFIG_CDP_POWER_CONSUMPTION 1024 1025 A 16bit integer containing the power consumption of the 1026 device in .1 of milliwatts. 1027 1028 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1029 1030 A byte containing the id of the VLAN. 1031 1032- Status LED: CONFIG_STATUS_LED 1033 1034 Several configurations allow to display the current 1035 status using a LED. For instance, the LED will blink 1036 fast while running U-Boot code, stop blinking as 1037 soon as a reply to a BOOTP request was received, and 1038 start blinking slow once the Linux kernel is running 1039 (supported by a status LED driver in the Linux 1040 kernel). Defining CONFIG_STATUS_LED enables this 1041 feature in U-Boot. 1042 1043- CAN Support: CONFIG_CAN_DRIVER 1044 1045 Defining CONFIG_CAN_DRIVER enables CAN driver support 1046 on those systems that support this (optional) 1047 feature, like the TQM8xxL modules. 1048 1049- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1050 1051 These enable I2C serial bus commands. Defining either of 1052 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1053 include the appropriate I2C driver for the selected cpu. 1054 1055 This will allow you to use i2c commands at the u-boot 1056 command line (as long as you set CFG_CMD_I2C in 1057 CONFIG_COMMANDS) and communicate with i2c based realtime 1058 clock chips. See common/cmd_i2c.c for a description of the 1059 command line interface. 1060 1061 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 1062 1063 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1064 bit-banging) driver instead of CPM or similar hardware 1065 support for I2C. 1066 1067 There are several other quantities that must also be 1068 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1069 1070 In both cases you will need to define CFG_I2C_SPEED 1071 to be the frequency (in Hz) at which you wish your i2c bus 1072 to run and CFG_I2C_SLAVE to be the address of this node (ie 1073 the cpu's i2c node address). 1074 1075 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1076 sets the cpu up as a master node and so its address should 1077 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1078 p.16-473). So, set CFG_I2C_SLAVE to 0. 1079 1080 That's all that's required for CONFIG_HARD_I2C. 1081 1082 If you use the software i2c interface (CONFIG_SOFT_I2C) 1083 then the following macros need to be defined (examples are 1084 from include/configs/lwmon.h): 1085 1086 I2C_INIT 1087 1088 (Optional). Any commands necessary to enable the I2C 1089 controller or configure ports. 1090 1091 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1092 1093 I2C_PORT 1094 1095 (Only for MPC8260 CPU). The I/O port to use (the code 1096 assumes both bits are on the same port). Valid values 1097 are 0..3 for ports A..D. 1098 1099 I2C_ACTIVE 1100 1101 The code necessary to make the I2C data line active 1102 (driven). If the data line is open collector, this 1103 define can be null. 1104 1105 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1106 1107 I2C_TRISTATE 1108 1109 The code necessary to make the I2C data line tri-stated 1110 (inactive). If the data line is open collector, this 1111 define can be null. 1112 1113 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1114 1115 I2C_READ 1116 1117 Code that returns TRUE if the I2C data line is high, 1118 FALSE if it is low. 1119 1120 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1121 1122 I2C_SDA(bit) 1123 1124 If <bit> is TRUE, sets the I2C data line high. If it 1125 is FALSE, it clears it (low). 1126 1127 eg: #define I2C_SDA(bit) \ 1128 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1129 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1130 1131 I2C_SCL(bit) 1132 1133 If <bit> is TRUE, sets the I2C clock line high. If it 1134 is FALSE, it clears it (low). 1135 1136 eg: #define I2C_SCL(bit) \ 1137 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1138 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1139 1140 I2C_DELAY 1141 1142 This delay is invoked four times per clock cycle so this 1143 controls the rate of data transfer. The data rate thus 1144 is 1 / (I2C_DELAY * 4). Often defined to be something 1145 like: 1146 1147 #define I2C_DELAY udelay(2) 1148 1149 CFG_I2C_INIT_BOARD 1150 1151 When a board is reset during an i2c bus transfer 1152 chips might think that the current transfer is still 1153 in progress. On some boards it is possible to access 1154 the i2c SCLK line directly, either by using the 1155 processor pin as a GPIO or by having a second pin 1156 connected to the bus. If this option is defined a 1157 custom i2c_init_board() routine in boards/xxx/board.c 1158 is run early in the boot sequence. 1159 1160 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1161 1162 This option enables configuration of bi_iic_fast[] flags 1163 in u-boot bd_info structure based on u-boot environment 1164 variable "i2cfast". (see also i2cfast) 1165 1166- SPI Support: CONFIG_SPI 1167 1168 Enables SPI driver (so far only tested with 1169 SPI EEPROM, also an instance works with Crystal A/D and 1170 D/As on the SACSng board) 1171 1172 CONFIG_SPI_X 1173 1174 Enables extended (16-bit) SPI EEPROM addressing. 1175 (symmetrical to CONFIG_I2C_X) 1176 1177 CONFIG_SOFT_SPI 1178 1179 Enables a software (bit-bang) SPI driver rather than 1180 using hardware support. This is a general purpose 1181 driver that only requires three general I/O port pins 1182 (two outputs, one input) to function. If this is 1183 defined, the board configuration must define several 1184 SPI configuration items (port pins to use, etc). For 1185 an example, see include/configs/sacsng.h. 1186 1187- FPGA Support: CONFIG_FPGA_COUNT 1188 1189 Specify the number of FPGA devices to support. 1190 1191 CONFIG_FPGA 1192 1193 Used to specify the types of FPGA devices. For example, 1194 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1195 1196 CFG_FPGA_PROG_FEEDBACK 1197 1198 Enable printing of hash marks during FPGA configuration. 1199 1200 CFG_FPGA_CHECK_BUSY 1201 1202 Enable checks on FPGA configuration interface busy 1203 status by the configuration function. This option 1204 will require a board or device specific function to 1205 be written. 1206 1207 CONFIG_FPGA_DELAY 1208 1209 If defined, a function that provides delays in the FPGA 1210 configuration driver. 1211 1212 CFG_FPGA_CHECK_CTRLC 1213 Allow Control-C to interrupt FPGA configuration 1214 1215 CFG_FPGA_CHECK_ERROR 1216 1217 Check for configuration errors during FPGA bitfile 1218 loading. For example, abort during Virtex II 1219 configuration if the INIT_B line goes low (which 1220 indicated a CRC error). 1221 1222 CFG_FPGA_WAIT_INIT 1223 1224 Maximum time to wait for the INIT_B line to deassert 1225 after PROB_B has been deasserted during a Virtex II 1226 FPGA configuration sequence. The default time is 500 1227 mS. 1228 1229 CFG_FPGA_WAIT_BUSY 1230 1231 Maximum time to wait for BUSY to deassert during 1232 Virtex II FPGA configuration. The default is 5 mS. 1233 1234 CFG_FPGA_WAIT_CONFIG 1235 1236 Time to wait after FPGA configuration. The default is 1237 200 mS. 1238 1239- Configuration Management: 1240 CONFIG_IDENT_STRING 1241 1242 If defined, this string will be added to the U-Boot 1243 version information (U_BOOT_VERSION) 1244 1245- Vendor Parameter Protection: 1246 1247 U-Boot considers the values of the environment 1248 variables "serial#" (Board Serial Number) and 1249 "ethaddr" (Ethernet Address) to be parameters that 1250 are set once by the board vendor / manufacturer, and 1251 protects these variables from casual modification by 1252 the user. Once set, these variables are read-only, 1253 and write or delete attempts are rejected. You can 1254 change this behviour: 1255 1256 If CONFIG_ENV_OVERWRITE is #defined in your config 1257 file, the write protection for vendor parameters is 1258 completely disabled. Anybody can change or delete 1259 these parameters. 1260 1261 Alternatively, if you #define _both_ CONFIG_ETHADDR 1262 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1263 ethernet address is installed in the environment, 1264 which can be changed exactly ONCE by the user. [The 1265 serial# is unaffected by this, i. e. it remains 1266 read-only.] 1267 1268- Protected RAM: 1269 CONFIG_PRAM 1270 1271 Define this variable to enable the reservation of 1272 "protected RAM", i. e. RAM which is not overwritten 1273 by U-Boot. Define CONFIG_PRAM to hold the number of 1274 kB you want to reserve for pRAM. You can overwrite 1275 this default value by defining an environment 1276 variable "pram" to the number of kB you want to 1277 reserve. Note that the board info structure will 1278 still show the full amount of RAM. If pRAM is 1279 reserved, a new environment variable "mem" will 1280 automatically be defined to hold the amount of 1281 remaining RAM in a form that can be passed as boot 1282 argument to Linux, for instance like that: 1283 1284 setenv bootargs ... mem=\$(mem) 1285 saveenv 1286 1287 This way you can tell Linux not to use this memory, 1288 either, which results in a memory region that will 1289 not be affected by reboots. 1290 1291 *WARNING* If your board configuration uses automatic 1292 detection of the RAM size, you must make sure that 1293 this memory test is non-destructive. So far, the 1294 following board configurations are known to be 1295 "pRAM-clean": 1296 1297 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1298 HERMES, IP860, RPXlite, LWMON, LANTEC, 1299 PCU_E, FLAGADM, TQM8260 1300 1301- Error Recovery: 1302 CONFIG_PANIC_HANG 1303 1304 Define this variable to stop the system in case of a 1305 fatal error, so that you have to reset it manually. 1306 This is probably NOT a good idea for an embedded 1307 system where you want to system to reboot 1308 automatically as fast as possible, but it may be 1309 useful during development since you can try to debug 1310 the conditions that lead to the situation. 1311 1312 CONFIG_NET_RETRY_COUNT 1313 1314 This variable defines the number of retries for 1315 network operations like ARP, RARP, TFTP, or BOOTP 1316 before giving up the operation. If not defined, a 1317 default value of 5 is used. 1318 1319- Command Interpreter: 1320 CFG_AUTO_COMPLETE 1321 1322 Enable auto completion of commands using TAB. 1323 1324 CFG_HUSH_PARSER 1325 1326 Define this variable to enable the "hush" shell (from 1327 Busybox) as command line interpreter, thus enabling 1328 powerful command line syntax like 1329 if...then...else...fi conditionals or `&&' and '||' 1330 constructs ("shell scripts"). 1331 1332 If undefined, you get the old, much simpler behaviour 1333 with a somewhat smaller memory footprint. 1334 1335 1336 CFG_PROMPT_HUSH_PS2 1337 1338 This defines the secondary prompt string, which is 1339 printed when the command interpreter needs more input 1340 to complete a command. Usually "> ". 1341 1342 Note: 1343 1344 In the current implementation, the local variables 1345 space and global environment variables space are 1346 separated. Local variables are those you define by 1347 simply typing `name=value'. To access a local 1348 variable later on, you have write `$name' or 1349 `${name}'; to execute the contents of a variable 1350 directly type `$name' at the command prompt. 1351 1352 Global environment variables are those you use 1353 setenv/printenv to work with. To run a command stored 1354 in such a variable, you need to use the run command, 1355 and you must not use the '$' sign to access them. 1356 1357 To store commands and special characters in a 1358 variable, please use double quotation marks 1359 surrounding the whole text of the variable, instead 1360 of the backslashes before semicolons and special 1361 symbols. 1362 1363- Default Environment: 1364 CONFIG_EXTRA_ENV_SETTINGS 1365 1366 Define this to contain any number of null terminated 1367 strings (variable = value pairs) that will be part of 1368 the default environment compiled into the boot image. 1369 1370 For example, place something like this in your 1371 board's config file: 1372 1373 #define CONFIG_EXTRA_ENV_SETTINGS \ 1374 "myvar1=value1\0" \ 1375 "myvar2=value2\0" 1376 1377 Warning: This method is based on knowledge about the 1378 internal format how the environment is stored by the 1379 U-Boot code. This is NOT an official, exported 1380 interface! Although it is unlikely that this format 1381 will change soon, there is no guarantee either. 1382 You better know what you are doing here. 1383 1384 Note: overly (ab)use of the default environment is 1385 discouraged. Make sure to check other ways to preset 1386 the environment like the autoscript function or the 1387 boot command first. 1388 1389- DataFlash Support: 1390 CONFIG_HAS_DATAFLASH 1391 1392 Defining this option enables DataFlash features and 1393 allows to read/write in Dataflash via the standard 1394 commands cp, md... 1395 1396- SystemACE Support: 1397 CONFIG_SYSTEMACE 1398 1399 Adding this option adds support for Xilinx SystemACE 1400 chips attached via some sort of local bus. The address 1401 of the chip must alsh be defined in the 1402 CFG_SYSTEMACE_BASE macro. For example: 1403 1404 #define CONFIG_SYSTEMACE 1405 #define CFG_SYSTEMACE_BASE 0xf0000000 1406 1407 When SystemACE support is added, the "ace" device type 1408 becomes available to the fat commands, i.e. fatls. 1409 1410- Show boot progress: 1411 CONFIG_SHOW_BOOT_PROGRESS 1412 1413 Defining this option allows to add some board- 1414 specific code (calling a user-provided function 1415 "show_boot_progress(int)") that enables you to show 1416 the system's boot progress on some display (for 1417 example, some LED's) on your board. At the moment, 1418 the following checkpoints are implemented: 1419 1420 Arg Where When 1421 1 common/cmd_bootm.c before attempting to boot an image 1422 -1 common/cmd_bootm.c Image header has bad magic number 1423 2 common/cmd_bootm.c Image header has correct magic number 1424 -2 common/cmd_bootm.c Image header has bad checksum 1425 3 common/cmd_bootm.c Image header has correct checksum 1426 -3 common/cmd_bootm.c Image data has bad checksum 1427 4 common/cmd_bootm.c Image data has correct checksum 1428 -4 common/cmd_bootm.c Image is for unsupported architecture 1429 5 common/cmd_bootm.c Architecture check OK 1430 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1431 6 common/cmd_bootm.c Image Type check OK 1432 -6 common/cmd_bootm.c gunzip uncompression error 1433 -7 common/cmd_bootm.c Unimplemented compression type 1434 7 common/cmd_bootm.c Uncompression OK 1435 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1436 8 common/cmd_bootm.c Image Type check OK 1437 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1438 9 common/cmd_bootm.c Start initial ramdisk verification 1439 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1440 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1441 10 common/cmd_bootm.c Ramdisk header is OK 1442 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1443 11 common/cmd_bootm.c Ramdisk data has correct checksum 1444 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1445 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1446 13 common/cmd_bootm.c Start multifile image verification 1447 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1448 15 common/cmd_bootm.c All preparation done, transferring control to OS 1449 1450 -30 lib_ppc/board.c Fatal error, hang the system 1451 -31 post/post.c POST test failed, detected by post_output_backlog() 1452 -32 post/post.c POST test failed, detected by post_run_single() 1453 1454 -1 common/cmd_doc.c Bad usage of "doc" command 1455 -1 common/cmd_doc.c No boot device 1456 -1 common/cmd_doc.c Unknown Chip ID on boot device 1457 -1 common/cmd_doc.c Read Error on boot device 1458 -1 common/cmd_doc.c Image header has bad magic number 1459 1460 -1 common/cmd_ide.c Bad usage of "ide" command 1461 -1 common/cmd_ide.c No boot device 1462 -1 common/cmd_ide.c Unknown boot device 1463 -1 common/cmd_ide.c Unknown partition table 1464 -1 common/cmd_ide.c Invalid partition type 1465 -1 common/cmd_ide.c Read Error on boot device 1466 -1 common/cmd_ide.c Image header has bad magic number 1467 1468 -1 common/cmd_nand.c Bad usage of "nand" command 1469 -1 common/cmd_nand.c No boot device 1470 -1 common/cmd_nand.c Unknown Chip ID on boot device 1471 -1 common/cmd_nand.c Read Error on boot device 1472 -1 common/cmd_nand.c Image header has bad magic number 1473 1474 -1 common/env_common.c Environment has a bad CRC, using default 1475 1476 1477Modem Support: 1478-------------- 1479 1480[so far only for SMDK2400 and TRAB boards] 1481 1482- Modem support endable: 1483 CONFIG_MODEM_SUPPORT 1484 1485- RTS/CTS Flow control enable: 1486 CONFIG_HWFLOW 1487 1488- Modem debug support: 1489 CONFIG_MODEM_SUPPORT_DEBUG 1490 1491 Enables debugging stuff (char screen[1024], dbg()) 1492 for modem support. Useful only with BDI2000. 1493 1494- Interrupt support (PPC): 1495 1496 There are common interrupt_init() and timer_interrupt() 1497 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1498 for cpu specific initialization. interrupt_init_cpu() 1499 should set decrementer_count to appropriate value. If 1500 cpu resets decrementer automatically after interrupt 1501 (ppc4xx) it should set decrementer_count to zero. 1502 timer_interrupt() calls timer_interrupt_cpu() for cpu 1503 specific handling. If board has watchdog / status_led 1504 / other_activity_monitor it works automatically from 1505 general timer_interrupt(). 1506 1507- General: 1508 1509 In the target system modem support is enabled when a 1510 specific key (key combination) is pressed during 1511 power-on. Otherwise U-Boot will boot normally 1512 (autoboot). The key_pressed() fuction is called from 1513 board_init(). Currently key_pressed() is a dummy 1514 function, returning 1 and thus enabling modem 1515 initialization. 1516 1517 If there are no modem init strings in the 1518 environment, U-Boot proceed to autoboot; the 1519 previous output (banner, info printfs) will be 1520 supressed, though. 1521 1522 See also: doc/README.Modem 1523 1524 1525Configuration Settings: 1526----------------------- 1527 1528- CFG_LONGHELP: Defined when you want long help messages included; 1529 undefine this when you're short of memory. 1530 1531- CFG_PROMPT: This is what U-Boot prints on the console to 1532 prompt for user input. 1533 1534- CFG_CBSIZE: Buffer size for input from the Console 1535 1536- CFG_PBSIZE: Buffer size for Console output 1537 1538- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1539 1540- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1541 the application (usually a Linux kernel) when it is 1542 booted 1543 1544- CFG_BAUDRATE_TABLE: 1545 List of legal baudrate settings for this board. 1546 1547- CFG_CONSOLE_INFO_QUIET 1548 Suppress display of console information at boot. 1549 1550- CFG_CONSOLE_IS_IN_ENV 1551 If the board specific function 1552 extern int overwrite_console (void); 1553 returns 1, the stdin, stderr and stdout are switched to the 1554 serial port, else the settings in the environment are used. 1555 1556- CFG_CONSOLE_OVERWRITE_ROUTINE 1557 Enable the call to overwrite_console(). 1558 1559- CFG_CONSOLE_ENV_OVERWRITE 1560 Enable overwrite of previous console environment settings. 1561 1562- CFG_MEMTEST_START, CFG_MEMTEST_END: 1563 Begin and End addresses of the area used by the 1564 simple memory test. 1565 1566- CFG_ALT_MEMTEST: 1567 Enable an alternate, more extensive memory test. 1568 1569- CFG_MEMTEST_SCRATCH: 1570 Scratch address used by the alternate memory test 1571 You only need to set this if address zero isn't writeable 1572 1573- CFG_TFTP_LOADADDR: 1574 Default load address for network file downloads 1575 1576- CFG_LOADS_BAUD_CHANGE: 1577 Enable temporary baudrate change while serial download 1578 1579- CFG_SDRAM_BASE: 1580 Physical start address of SDRAM. _Must_ be 0 here. 1581 1582- CFG_MBIO_BASE: 1583 Physical start address of Motherboard I/O (if using a 1584 Cogent motherboard) 1585 1586- CFG_FLASH_BASE: 1587 Physical start address of Flash memory. 1588 1589- CFG_MONITOR_BASE: 1590 Physical start address of boot monitor code (set by 1591 make config files to be same as the text base address 1592 (TEXT_BASE) used when linking) - same as 1593 CFG_FLASH_BASE when booting from flash. 1594 1595- CFG_MONITOR_LEN: 1596 Size of memory reserved for monitor code, used to 1597 determine _at_compile_time_ (!) if the environment is 1598 embedded within the U-Boot image, or in a separate 1599 flash sector. 1600 1601- CFG_MALLOC_LEN: 1602 Size of DRAM reserved for malloc() use. 1603 1604- CFG_BOOTMAPSZ: 1605 Maximum size of memory mapped by the startup code of 1606 the Linux kernel; all data that must be processed by 1607 the Linux kernel (bd_info, boot arguments, eventually 1608 initrd image) must be put below this limit. 1609 1610- CFG_MAX_FLASH_BANKS: 1611 Max number of Flash memory banks 1612 1613- CFG_MAX_FLASH_SECT: 1614 Max number of sectors on a Flash chip 1615 1616- CFG_FLASH_ERASE_TOUT: 1617 Timeout for Flash erase operations (in ms) 1618 1619- CFG_FLASH_WRITE_TOUT: 1620 Timeout for Flash write operations (in ms) 1621 1622- CFG_FLASH_LOCK_TOUT 1623 Timeout for Flash set sector lock bit operation (in ms) 1624 1625- CFG_FLASH_UNLOCK_TOUT 1626 Timeout for Flash clear lock bits operation (in ms) 1627 1628- CFG_FLASH_PROTECTION 1629 If defined, hardware flash sectors protection is used 1630 instead of U-Boot software protection. 1631 1632- CFG_DIRECT_FLASH_TFTP: 1633 1634 Enable TFTP transfers directly to flash memory; 1635 without this option such a download has to be 1636 performed in two steps: (1) download to RAM, and (2) 1637 copy from RAM to flash. 1638 1639 The two-step approach is usually more reliable, since 1640 you can check if the download worked before you erase 1641 the flash, but in some situations (when sytem RAM is 1642 too limited to allow for a tempory copy of the 1643 downloaded image) this option may be very useful. 1644 1645- CFG_FLASH_CFI: 1646 Define if the flash driver uses extra elements in the 1647 common flash structure for storing flash geometry. 1648 1649- CFG_FLASH_CFI_DRIVER 1650 This option also enables the building of the cfi_flash driver 1651 in the drivers directory 1652 1653- CFG_RX_ETH_BUFFER: 1654 Defines the number of ethernet receive buffers. On some 1655 ethernet controllers it is recommended to set this value 1656 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1657 buffers can be full shortly after enabling the interface 1658 on high ethernet traffic. 1659 Defaults to 4 if not defined. 1660 1661The following definitions that deal with the placement and management 1662of environment data (variable area); in general, we support the 1663following configurations: 1664 1665- CFG_ENV_IS_IN_FLASH: 1666 1667 Define this if the environment is in flash memory. 1668 1669 a) The environment occupies one whole flash sector, which is 1670 "embedded" in the text segment with the U-Boot code. This 1671 happens usually with "bottom boot sector" or "top boot 1672 sector" type flash chips, which have several smaller 1673 sectors at the start or the end. For instance, such a 1674 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1675 such a case you would place the environment in one of the 1676 4 kB sectors - with U-Boot code before and after it. With 1677 "top boot sector" type flash chips, you would put the 1678 environment in one of the last sectors, leaving a gap 1679 between U-Boot and the environment. 1680 1681 - CFG_ENV_OFFSET: 1682 1683 Offset of environment data (variable area) to the 1684 beginning of flash memory; for instance, with bottom boot 1685 type flash chips the second sector can be used: the offset 1686 for this sector is given here. 1687 1688 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1689 1690 - CFG_ENV_ADDR: 1691 1692 This is just another way to specify the start address of 1693 the flash sector containing the environment (instead of 1694 CFG_ENV_OFFSET). 1695 1696 - CFG_ENV_SECT_SIZE: 1697 1698 Size of the sector containing the environment. 1699 1700 1701 b) Sometimes flash chips have few, equal sized, BIG sectors. 1702 In such a case you don't want to spend a whole sector for 1703 the environment. 1704 1705 - CFG_ENV_SIZE: 1706 1707 If you use this in combination with CFG_ENV_IS_IN_FLASH 1708 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1709 of this flash sector for the environment. This saves 1710 memory for the RAM copy of the environment. 1711 1712 It may also save flash memory if you decide to use this 1713 when your environment is "embedded" within U-Boot code, 1714 since then the remainder of the flash sector could be used 1715 for U-Boot code. It should be pointed out that this is 1716 STRONGLY DISCOURAGED from a robustness point of view: 1717 updating the environment in flash makes it always 1718 necessary to erase the WHOLE sector. If something goes 1719 wrong before the contents has been restored from a copy in 1720 RAM, your target system will be dead. 1721 1722 - CFG_ENV_ADDR_REDUND 1723 CFG_ENV_SIZE_REDUND 1724 1725 These settings describe a second storage area used to hold 1726 a redundand copy of the environment data, so that there is 1727 a valid backup copy in case there is a power failure during 1728 a "saveenv" operation. 1729 1730BE CAREFUL! Any changes to the flash layout, and some changes to the 1731source code will make it necessary to adapt <board>/u-boot.lds* 1732accordingly! 1733 1734 1735- CFG_ENV_IS_IN_NVRAM: 1736 1737 Define this if you have some non-volatile memory device 1738 (NVRAM, battery buffered SRAM) which you want to use for the 1739 environment. 1740 1741 - CFG_ENV_ADDR: 1742 - CFG_ENV_SIZE: 1743 1744 These two #defines are used to determin the memory area you 1745 want to use for environment. It is assumed that this memory 1746 can just be read and written to, without any special 1747 provision. 1748 1749BE CAREFUL! The first access to the environment happens quite early 1750in U-Boot initalization (when we try to get the setting of for the 1751console baudrate). You *MUST* have mappend your NVRAM area then, or 1752U-Boot will hang. 1753 1754Please note that even with NVRAM we still use a copy of the 1755environment in RAM: we could work on NVRAM directly, but we want to 1756keep settings there always unmodified except somebody uses "saveenv" 1757to save the current settings. 1758 1759 1760- CFG_ENV_IS_IN_EEPROM: 1761 1762 Use this if you have an EEPROM or similar serial access 1763 device and a driver for it. 1764 1765 - CFG_ENV_OFFSET: 1766 - CFG_ENV_SIZE: 1767 1768 These two #defines specify the offset and size of the 1769 environment area within the total memory of your EEPROM. 1770 1771 - CFG_I2C_EEPROM_ADDR: 1772 If defined, specified the chip address of the EEPROM device. 1773 The default address is zero. 1774 1775 - CFG_EEPROM_PAGE_WRITE_BITS: 1776 If defined, the number of bits used to address bytes in a 1777 single page in the EEPROM device. A 64 byte page, for example 1778 would require six bits. 1779 1780 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1781 If defined, the number of milliseconds to delay between 1782 page writes. The default is zero milliseconds. 1783 1784 - CFG_I2C_EEPROM_ADDR_LEN: 1785 The length in bytes of the EEPROM memory array address. Note 1786 that this is NOT the chip address length! 1787 1788 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 1789 EEPROM chips that implement "address overflow" are ones 1790 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 1791 address and the extra bits end up in the "chip address" bit 1792 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 1793 byte chips. 1794 1795 Note that we consider the length of the address field to 1796 still be one byte because the extra address bits are hidden 1797 in the chip address. 1798 1799 - CFG_EEPROM_SIZE: 1800 The size in bytes of the EEPROM device. 1801 1802 1803- CFG_ENV_IS_IN_DATAFLASH: 1804 1805 Define this if you have a DataFlash memory device which you 1806 want to use for the environment. 1807 1808 - CFG_ENV_OFFSET: 1809 - CFG_ENV_ADDR: 1810 - CFG_ENV_SIZE: 1811 1812 These three #defines specify the offset and size of the 1813 environment area within the total memory of your DataFlash placed 1814 at the specified address. 1815 1816 1817- CFG_SPI_INIT_OFFSET 1818 1819 Defines offset to the initial SPI buffer area in DPRAM. The 1820 area is used at an early stage (ROM part) if the environment 1821 is configured to reside in the SPI EEPROM: We need a 520 byte 1822 scratch DPRAM area. It is used between the two initialization 1823 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1824 to be a good choice since it makes it far enough from the 1825 start of the data area as well as from the stack pointer. 1826 1827Please note that the environment is read-only as long as the monitor 1828has been relocated to RAM and a RAM copy of the environment has been 1829created; also, when using EEPROM you will have to use getenv_r() 1830until then to read environment variables. 1831 1832The environment is protected by a CRC32 checksum. Before the monitor 1833is relocated into RAM, as a result of a bad CRC you will be working 1834with the compiled-in default environment - *silently*!!! [This is 1835necessary, because the first environment variable we need is the 1836"baudrate" setting for the console - if we have a bad CRC, we don't 1837have any device yet where we could complain.] 1838 1839Note: once the monitor has been relocated, then it will complain if 1840the default environment is used; a new CRC is computed as soon as you 1841use the "saveenv" command to store a valid environment. 1842 1843- CFG_FAULT_ECHO_LINK_DOWN: 1844 Echo the inverted Ethernet link state to the fault LED. 1845 1846 Note: If this option is active, then CFG_FAULT_MII_ADDR 1847 also needs to be defined. 1848 1849- CFG_FAULT_MII_ADDR: 1850 MII address of the PHY to check for the Ethernet link state. 1851 1852- CFG_64BIT_VSPRINTF: 1853 Makes vsprintf (and all *printf functions) support printing 1854 of 64bit values by using the L quantifier 1855 1856- CFG_64BIT_STRTOUL: 1857 Adds simple_strtoull that returns a 64bit value 1858 1859Low Level (hardware related) configuration options: 1860--------------------------------------------------- 1861 1862- CFG_CACHELINE_SIZE: 1863 Cache Line Size of the CPU. 1864 1865- CFG_DEFAULT_IMMR: 1866 Default address of the IMMR after system reset. 1867 1868 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1869 and RPXsuper) to be able to adjust the position of 1870 the IMMR register after a reset. 1871 1872- Floppy Disk Support: 1873 CFG_FDC_DRIVE_NUMBER 1874 1875 the default drive number (default value 0) 1876 1877 CFG_ISA_IO_STRIDE 1878 1879 defines the spacing between fdc chipset registers 1880 (default value 1) 1881 1882 CFG_ISA_IO_OFFSET 1883 1884 defines the offset of register from address. It 1885 depends on which part of the data bus is connected to 1886 the fdc chipset. (default value 0) 1887 1888 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1889 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1890 default value. 1891 1892 if CFG_FDC_HW_INIT is defined, then the function 1893 fdc_hw_init() is called at the beginning of the FDC 1894 setup. fdc_hw_init() must be provided by the board 1895 source code. It is used to make hardware dependant 1896 initializations. 1897 1898- CFG_IMMR: Physical address of the Internal Memory Mapped 1899 Register; DO NOT CHANGE! (11-4) 1900 [MPC8xx systems only] 1901 1902- CFG_INIT_RAM_ADDR: 1903 1904 Start address of memory area that can be used for 1905 initial data and stack; please note that this must be 1906 writable memory that is working WITHOUT special 1907 initialization, i. e. you CANNOT use normal RAM which 1908 will become available only after programming the 1909 memory controller and running certain initialization 1910 sequences. 1911 1912 U-Boot uses the following memory types: 1913 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1914 - MPC824X: data cache 1915 - PPC4xx: data cache 1916 1917- CFG_GBL_DATA_OFFSET: 1918 1919 Offset of the initial data structure in the memory 1920 area defined by CFG_INIT_RAM_ADDR. Usually 1921 CFG_GBL_DATA_OFFSET is chosen such that the initial 1922 data is located at the end of the available space 1923 (sometimes written as (CFG_INIT_RAM_END - 1924 CFG_INIT_DATA_SIZE), and the initial stack is just 1925 below that area (growing from (CFG_INIT_RAM_ADDR + 1926 CFG_GBL_DATA_OFFSET) downward. 1927 1928 Note: 1929 On the MPC824X (or other systems that use the data 1930 cache for initial memory) the address chosen for 1931 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1932 point to an otherwise UNUSED address space between 1933 the top of RAM and the start of the PCI space. 1934 1935- CFG_SIUMCR: SIU Module Configuration (11-6) 1936 1937- CFG_SYPCR: System Protection Control (11-9) 1938 1939- CFG_TBSCR: Time Base Status and Control (11-26) 1940 1941- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1942 1943- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1944 1945- CFG_SCCR: System Clock and reset Control Register (15-27) 1946 1947- CFG_OR_TIMING_SDRAM: 1948 SDRAM timing 1949 1950- CFG_MAMR_PTA: 1951 periodic timer for refresh 1952 1953- CFG_DER: Debug Event Register (37-47) 1954 1955- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1956 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1957 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1958 CFG_BR1_PRELIM: 1959 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1960 1961- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1962 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1963 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1964 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1965 1966- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1967 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1968 Machine Mode Register and Memory Periodic Timer 1969 Prescaler definitions (SDRAM timing) 1970 1971- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1972 enable I2C microcode relocation patch (MPC8xx); 1973 define relocation offset in DPRAM [DSP2] 1974 1975- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1976 enable SPI microcode relocation patch (MPC8xx); 1977 define relocation offset in DPRAM [SCC4] 1978 1979- CFG_USE_OSCCLK: 1980 Use OSCM clock mode on MBX8xx board. Be careful, 1981 wrong setting might damage your board. Read 1982 doc/README.MBX before setting this variable! 1983 1984- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1985 Offset of the bootmode word in DPRAM used by post 1986 (Power On Self Tests). This definition overrides 1987 #define'd default value in commproc.h resp. 1988 cpm_8260.h. 1989 1990- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 1991 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 1992 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 1993 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 1994 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 1995 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 1996 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 1997 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 1998 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 1999 2000- CONFIG_ETHER_ON_FEC[12] 2001 Define to enable FEC[12] on a 8xx series processor. 2002 2003- CONFIG_FEC[12]_PHY 2004 Define to the hardcoded PHY address which corresponds 2005 to the given FEC; i. e. 2006 #define CONFIG_FEC1_PHY 4 2007 means that the PHY with address 4 is connected to FEC1 2008 2009 When set to -1, means to probe for first available. 2010 2011- CONFIG_FEC[12]_PHY_NORXERR 2012 The PHY does not have a RXERR line (RMII only). 2013 (so program the FEC to ignore it). 2014 2015- CONFIG_RMII 2016 Enable RMII mode for all FECs. 2017 Note that this is a global option, we can't 2018 have one FEC in standard MII mode and another in RMII mode. 2019 2020- CONFIG_CRC32_VERIFY 2021 Add a verify option to the crc32 command. 2022 The syntax is: 2023 2024 => crc32 -v <address> <count> <crc32> 2025 2026 Where address/count indicate a memory area 2027 and crc32 is the correct crc32 which the 2028 area should have. 2029 2030Building the Software: 2031====================== 2032 2033Building U-Boot has been tested in native PPC environments (on a 2034PowerBook G3 running LinuxPPC 2000) and in cross environments 2035(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2036NetBSD 1.5 on x86). 2037 2038If you are not using a native PPC environment, it is assumed that you 2039have the GNU cross compiling tools available in your path and named 2040with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2041you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2042the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2043change it to: 2044 2045 CROSS_COMPILE = ppc_4xx- 2046 2047 2048U-Boot is intended to be simple to build. After installing the 2049sources you must configure U-Boot for one specific board type. This 2050is done by typing: 2051 2052 make NAME_config 2053 2054where "NAME_config" is the name of one of the existing 2055configurations; the following names are supported: 2056 2057 ADCIOP_config FPS850L_config omap1610inn_config 2058 ADS860_config FPS860L_config pcu_e_config 2059 AR405_config GEN860T_config PIP405_config 2060 at91rm9200dk_config GENIETV_config QS823_config 2061 CANBT_config GTH_config QS850_config 2062 cmi_mpc5xx_config hermes_config QS860T_config 2063 cogent_common_config hymod_config RPXlite_config 2064 cogent_mpc8260_config IP860_config RPXsuper_config 2065 cogent_mpc8xx_config IVML24_config rsdproto_config 2066 CPCI405_config IVMS8_config Sandpoint8240_config 2067 CPCIISER4_config JSE_config sbc8260_config 2068 csb272_config LANTEC_config SM850_config 2069 CU824_config lwmon_config SPD823TS_config 2070 DUET_ADS_config MBX860T_config stxgp3_config 2071 EBONY_config MBX_config SXNI855T_config 2072 ELPT860_config MPC8260ADS_config TQM823L_config 2073 ESTEEM192E_config MPC8540ADS_config TQM850L_config 2074 ETX094_config MPC8560ADS_config TQM855L_config 2075 FADS823_config NETVIA_config TQM860L_config 2076 FADS850SAR_config omap1510inn_config WALNUT405_config 2077 FADS860T_config omap1610h2_config ZPC1900_config 2078 omap730p2_config 2079 2080Note: for some board special configuration names may exist; check if 2081 additional information is available from the board vendor; for 2082 instance, the TQM823L systems are available without (standard) 2083 or with LCD support. You can select such additional "features" 2084 when chosing the configuration, i. e. 2085 2086 make TQM823L_config 2087 - will configure for a plain TQM823L, i. e. no LCD support 2088 2089 make TQM823L_LCD_config 2090 - will configure for a TQM823L with U-Boot console on LCD 2091 2092 etc. 2093 2094 2095Finally, type "make all", and you should get some working U-Boot 2096images ready for download to / installation on your system: 2097 2098- "u-boot.bin" is a raw binary image 2099- "u-boot" is an image in ELF binary format 2100- "u-boot.srec" is in Motorola S-Record format 2101 2102 2103Please be aware that the Makefiles assume you are using GNU make, so 2104for instance on NetBSD you might need to use "gmake" instead of 2105native "make". 2106 2107 2108If the system board that you have is not listed, then you will need 2109to port U-Boot to your hardware platform. To do this, follow these 2110steps: 2111 21121. Add a new configuration option for your board to the toplevel 2113 "Makefile" and to the "MAKEALL" script, using the existing 2114 entries as examples. Note that here and at many other places 2115 boards and other names are listed in alphabetical sort order. Please 2116 keep this order. 21172. Create a new directory to hold your board specific code. Add any 2118 files you need. In your board directory, you will need at least 2119 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 21203. Create a new configuration file "include/configs/<board>.h" for 2121 your board 21223. If you're porting U-Boot to a new CPU, then also create a new 2123 directory to hold your CPU specific code. Add any files you need. 21244. Run "make <board>_config" with your new name. 21255. Type "make", and you should get a working "u-boot.srec" file 2126 to be installed on your target system. 21276. Debug and solve any problems that might arise. 2128 [Of course, this last step is much harder than it sounds.] 2129 2130 2131Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2132============================================================== 2133 2134If you have modified U-Boot sources (for instance added a new board 2135or support for new devices, a new CPU, etc.) you are expected to 2136provide feedback to the other developers. The feedback normally takes 2137the form of a "patch", i. e. a context diff against a certain (latest 2138official or latest in CVS) version of U-Boot sources. 2139 2140But before you submit such a patch, please verify that your modifi- 2141cation did not break existing code. At least make sure that *ALL* of 2142the supported boards compile WITHOUT ANY compiler warnings. To do so, 2143just run the "MAKEALL" script, which will configure and build U-Boot 2144for ALL supported system. Be warned, this will take a while. You can 2145select which (cross) compiler to use by passing a `CROSS_COMPILE' 2146environment variable to the script, i. e. to use the cross tools from 2147MontaVista's Hard Hat Linux you can type 2148 2149 CROSS_COMPILE=ppc_8xx- MAKEALL 2150 2151or to build on a native PowerPC system you can type 2152 2153 CROSS_COMPILE=' ' MAKEALL 2154 2155See also "U-Boot Porting Guide" below. 2156 2157 2158Monitor Commands - Overview: 2159============================ 2160 2161go - start application at address 'addr' 2162run - run commands in an environment variable 2163bootm - boot application image from memory 2164bootp - boot image via network using BootP/TFTP protocol 2165tftpboot- boot image via network using TFTP protocol 2166 and env variables "ipaddr" and "serverip" 2167 (and eventually "gatewayip") 2168rarpboot- boot image via network using RARP/TFTP protocol 2169diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2170loads - load S-Record file over serial line 2171loadb - load binary file over serial line (kermit mode) 2172md - memory display 2173mm - memory modify (auto-incrementing) 2174nm - memory modify (constant address) 2175mw - memory write (fill) 2176cp - memory copy 2177cmp - memory compare 2178crc32 - checksum calculation 2179imd - i2c memory display 2180imm - i2c memory modify (auto-incrementing) 2181inm - i2c memory modify (constant address) 2182imw - i2c memory write (fill) 2183icrc32 - i2c checksum calculation 2184iprobe - probe to discover valid I2C chip addresses 2185iloop - infinite loop on address range 2186isdram - print SDRAM configuration information 2187sspi - SPI utility commands 2188base - print or set address offset 2189printenv- print environment variables 2190setenv - set environment variables 2191saveenv - save environment variables to persistent storage 2192protect - enable or disable FLASH write protection 2193erase - erase FLASH memory 2194flinfo - print FLASH memory information 2195bdinfo - print Board Info structure 2196iminfo - print header information for application image 2197coninfo - print console devices and informations 2198ide - IDE sub-system 2199loop - infinite loop on address range 2200mtest - simple RAM test 2201icache - enable or disable instruction cache 2202dcache - enable or disable data cache 2203reset - Perform RESET of the CPU 2204echo - echo args to console 2205version - print monitor version 2206help - print online help 2207? - alias for 'help' 2208 2209 2210Monitor Commands - Detailed Description: 2211======================================== 2212 2213TODO. 2214 2215For now: just type "help <command>". 2216 2217 2218Environment Variables: 2219====================== 2220 2221U-Boot supports user configuration using Environment Variables which 2222can be made persistent by saving to Flash memory. 2223 2224Environment Variables are set using "setenv", printed using 2225"printenv", and saved to Flash using "saveenv". Using "setenv" 2226without a value can be used to delete a variable from the 2227environment. As long as you don't save the environment you are 2228working with an in-memory copy. In case the Flash area containing the 2229environment is erased by accident, a default environment is provided. 2230 2231Some configuration options can be set using Environment Variables: 2232 2233 baudrate - see CONFIG_BAUDRATE 2234 2235 bootdelay - see CONFIG_BOOTDELAY 2236 2237 bootcmd - see CONFIG_BOOTCOMMAND 2238 2239 bootargs - Boot arguments when booting an RTOS image 2240 2241 bootfile - Name of the image to load with TFTP 2242 2243 autoload - if set to "no" (any string beginning with 'n'), 2244 "bootp" will just load perform a lookup of the 2245 configuration from the BOOTP server, but not try to 2246 load any image using TFTP 2247 2248 autostart - if set to "yes", an image loaded using the "bootp", 2249 "rarpboot", "tftpboot" or "diskboot" commands will 2250 be automatically started (by internally calling 2251 "bootm") 2252 2253 If set to "no", a standalone image passed to the 2254 "bootm" command will be copied to the load address 2255 (and eventually uncompressed), but NOT be started. 2256 This can be used to load and uncompress arbitrary 2257 data. 2258 2259 i2cfast - (PPC405GP|PPC405EP only) 2260 if set to 'y' configures Linux I2C driver for fast 2261 mode (400kHZ). This environment variable is used in 2262 initialization code. So, for changes to be effective 2263 it must be saved and board must be reset. 2264 2265 initrd_high - restrict positioning of initrd images: 2266 If this variable is not set, initrd images will be 2267 copied to the highest possible address in RAM; this 2268 is usually what you want since it allows for 2269 maximum initrd size. If for some reason you want to 2270 make sure that the initrd image is loaded below the 2271 CFG_BOOTMAPSZ limit, you can set this environment 2272 variable to a value of "no" or "off" or "0". 2273 Alternatively, you can set it to a maximum upper 2274 address to use (U-Boot will still check that it 2275 does not overwrite the U-Boot stack and data). 2276 2277 For instance, when you have a system with 16 MB 2278 RAM, and want to reserve 4 MB from use by Linux, 2279 you can do this by adding "mem=12M" to the value of 2280 the "bootargs" variable. However, now you must make 2281 sure that the initrd image is placed in the first 2282 12 MB as well - this can be done with 2283 2284 setenv initrd_high 00c00000 2285 2286 If you set initrd_high to 0xFFFFFFFF, this is an 2287 indication to U-Boot that all addresses are legal 2288 for the Linux kernel, including addresses in flash 2289 memory. In this case U-Boot will NOT COPY the 2290 ramdisk at all. This may be useful to reduce the 2291 boot time on your system, but requires that this 2292 feature is supported by your Linux kernel. 2293 2294 ipaddr - IP address; needed for tftpboot command 2295 2296 loadaddr - Default load address for commands like "bootp", 2297 "rarpboot", "tftpboot", "loadb" or "diskboot" 2298 2299 loads_echo - see CONFIG_LOADS_ECHO 2300 2301 serverip - TFTP server IP address; needed for tftpboot command 2302 2303 bootretry - see CONFIG_BOOT_RETRY_TIME 2304 2305 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2306 2307 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2308 2309 ethprime - When CONFIG_NET_MULTI is enabled controls which 2310 interface is used first. 2311 2312 ethact - When CONFIG_NET_MULTI is enabled controls which 2313 interface is currently active. For example you 2314 can do the following 2315 2316 => setenv ethact FEC ETHERNET 2317 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2318 => setenv ethact SCC ETHERNET 2319 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2320 2321 netretry - When set to "no" each network operation will 2322 either succeed or fail without retrying. 2323 When set to "once" the network operation will 2324 fail when all the available network interfaces 2325 are tried once without success. 2326 Useful on scripts which control the retry operation 2327 themselves. 2328 2329 vlan - When set to a value < 4095 the traffic over 2330 ethernet is encapsulated/received over 802.1q 2331 VLAN tagged frames. 2332 2333The following environment variables may be used and automatically 2334updated by the network boot commands ("bootp" and "rarpboot"), 2335depending the information provided by your boot server: 2336 2337 bootfile - see above 2338 dnsip - IP address of your Domain Name Server 2339 dnsip2 - IP address of your secondary Domain Name Server 2340 gatewayip - IP address of the Gateway (Router) to use 2341 hostname - Target hostname 2342 ipaddr - see above 2343 netmask - Subnet Mask 2344 rootpath - Pathname of the root filesystem on the NFS server 2345 serverip - see above 2346 2347 2348There are two special Environment Variables: 2349 2350 serial# - contains hardware identification information such 2351 as type string and/or serial number 2352 ethaddr - Ethernet address 2353 2354These variables can be set only once (usually during manufacturing of 2355the board). U-Boot refuses to delete or overwrite these variables 2356once they have been set once. 2357 2358 2359Further special Environment Variables: 2360 2361 ver - Contains the U-Boot version string as printed 2362 with the "version" command. This variable is 2363 readonly (see CONFIG_VERSION_VARIABLE). 2364 2365 2366Please note that changes to some configuration parameters may take 2367only effect after the next boot (yes, that's just like Windoze :-). 2368 2369 2370Command Line Parsing: 2371===================== 2372 2373There are two different command line parsers available with U-Boot: 2374the old "simple" one, and the much more powerful "hush" shell: 2375 2376Old, simple command line parser: 2377-------------------------------- 2378 2379- supports environment variables (through setenv / saveenv commands) 2380- several commands on one line, separated by ';' 2381- variable substitution using "... $(name) ..." syntax 2382- special characters ('$', ';') can be escaped by prefixing with '\', 2383 for example: 2384 setenv bootcmd bootm \$(address) 2385- You can also escape text by enclosing in single apostrophes, for example: 2386 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2387 2388Hush shell: 2389----------- 2390 2391- similar to Bourne shell, with control structures like 2392 if...then...else...fi, for...do...done; while...do...done, 2393 until...do...done, ... 2394- supports environment ("global") variables (through setenv / saveenv 2395 commands) and local shell variables (through standard shell syntax 2396 "name=value"); only environment variables can be used with "run" 2397 command 2398 2399General rules: 2400-------------- 2401 2402(1) If a command line (or an environment variable executed by a "run" 2403 command) contains several commands separated by semicolon, and 2404 one of these commands fails, then the remaining commands will be 2405 executed anyway. 2406 2407(2) If you execute several variables with one call to run (i. e. 2408 calling run with a list af variables as arguments), any failing 2409 command will cause "run" to terminate, i. e. the remaining 2410 variables are not executed. 2411 2412Note for Redundant Ethernet Interfaces: 2413======================================= 2414 2415Some boards come with redundant ethernet interfaces; U-Boot supports 2416such configurations and is capable of automatic selection of a 2417"working" interface when needed. MAC assignment works as follows: 2418 2419Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2420MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2421"eth1addr" (=>eth1), "eth2addr", ... 2422 2423If the network interface stores some valid MAC address (for instance 2424in SROM), this is used as default address if there is NO correspon- 2425ding setting in the environment; if the corresponding environment 2426variable is set, this overrides the settings in the card; that means: 2427 2428o If the SROM has a valid MAC address, and there is no address in the 2429 environment, the SROM's address is used. 2430 2431o If there is no valid address in the SROM, and a definition in the 2432 environment exists, then the value from the environment variable is 2433 used. 2434 2435o If both the SROM and the environment contain a MAC address, and 2436 both addresses are the same, this MAC address is used. 2437 2438o If both the SROM and the environment contain a MAC address, and the 2439 addresses differ, the value from the environment is used and a 2440 warning is printed. 2441 2442o If neither SROM nor the environment contain a MAC address, an error 2443 is raised. 2444 2445 2446Image Formats: 2447============== 2448 2449The "boot" commands of this monitor operate on "image" files which 2450can be basicly anything, preceeded by a special header; see the 2451definitions in include/image.h for details; basicly, the header 2452defines the following image properties: 2453 2454* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2455 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2456 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2457 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2458* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2459 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2460 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC). 2461* Compression Type (uncompressed, gzip, bzip2) 2462* Load Address 2463* Entry Point 2464* Image Name 2465* Image Timestamp 2466 2467The header is marked by a special Magic Number, and both the header 2468and the data portions of the image are secured against corruption by 2469CRC32 checksums. 2470 2471 2472Linux Support: 2473============== 2474 2475Although U-Boot should support any OS or standalone application 2476easily, the main focus has always been on Linux during the design of 2477U-Boot. 2478 2479U-Boot includes many features that so far have been part of some 2480special "boot loader" code within the Linux kernel. Also, any 2481"initrd" images to be used are no longer part of one big Linux image; 2482instead, kernel and "initrd" are separate images. This implementation 2483serves several purposes: 2484 2485- the same features can be used for other OS or standalone 2486 applications (for instance: using compressed images to reduce the 2487 Flash memory footprint) 2488 2489- it becomes much easier to port new Linux kernel versions because 2490 lots of low-level, hardware dependent stuff are done by U-Boot 2491 2492- the same Linux kernel image can now be used with different "initrd" 2493 images; of course this also means that different kernel images can 2494 be run with the same "initrd". This makes testing easier (you don't 2495 have to build a new "zImage.initrd" Linux image when you just 2496 change a file in your "initrd"). Also, a field-upgrade of the 2497 software is easier now. 2498 2499 2500Linux HOWTO: 2501============ 2502 2503Porting Linux to U-Boot based systems: 2504--------------------------------------- 2505 2506U-Boot cannot save you from doing all the necessary modifications to 2507configure the Linux device drivers for use with your target hardware 2508(no, we don't intend to provide a full virtual machine interface to 2509Linux :-). 2510 2511But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2512 2513Just make sure your machine specific header file (for instance 2514include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2515Information structure as we define in include/u-boot.h, and make 2516sure that your definition of IMAP_ADDR uses the same value as your 2517U-Boot configuration in CFG_IMMR. 2518 2519 2520Configuring the Linux kernel: 2521----------------------------- 2522 2523No specific requirements for U-Boot. Make sure you have some root 2524device (initial ramdisk, NFS) for your target system. 2525 2526 2527Building a Linux Image: 2528----------------------- 2529 2530With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2531not used. If you use recent kernel source, a new build target 2532"uImage" will exist which automatically builds an image usable by 2533U-Boot. Most older kernels also have support for a "pImage" target, 2534which was introduced for our predecessor project PPCBoot and uses a 2535100% compatible format. 2536 2537Example: 2538 2539 make TQM850L_config 2540 make oldconfig 2541 make dep 2542 make uImage 2543 2544The "uImage" build target uses a special tool (in 'tools/mkimage') to 2545encapsulate a compressed Linux kernel image with header information, 2546CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2547 2548* build a standard "vmlinux" kernel image (in ELF binary format): 2549 2550* convert the kernel into a raw binary image: 2551 2552 ${CROSS_COMPILE}-objcopy -O binary \ 2553 -R .note -R .comment \ 2554 -S vmlinux linux.bin 2555 2556* compress the binary image: 2557 2558 gzip -9 linux.bin 2559 2560* package compressed binary image for U-Boot: 2561 2562 mkimage -A ppc -O linux -T kernel -C gzip \ 2563 -a 0 -e 0 -n "Linux Kernel Image" \ 2564 -d linux.bin.gz uImage 2565 2566 2567The "mkimage" tool can also be used to create ramdisk images for use 2568with U-Boot, either separated from the Linux kernel image, or 2569combined into one file. "mkimage" encapsulates the images with a 64 2570byte header containing information about target architecture, 2571operating system, image type, compression method, entry points, time 2572stamp, CRC32 checksums, etc. 2573 2574"mkimage" can be called in two ways: to verify existing images and 2575print the header information, or to build new images. 2576 2577In the first form (with "-l" option) mkimage lists the information 2578contained in the header of an existing U-Boot image; this includes 2579checksum verification: 2580 2581 tools/mkimage -l image 2582 -l ==> list image header information 2583 2584The second form (with "-d" option) is used to build a U-Boot image 2585from a "data file" which is used as image payload: 2586 2587 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2588 -n name -d data_file image 2589 -A ==> set architecture to 'arch' 2590 -O ==> set operating system to 'os' 2591 -T ==> set image type to 'type' 2592 -C ==> set compression type 'comp' 2593 -a ==> set load address to 'addr' (hex) 2594 -e ==> set entry point to 'ep' (hex) 2595 -n ==> set image name to 'name' 2596 -d ==> use image data from 'datafile' 2597 2598Right now, all Linux kernels for PowerPC systems use the same load 2599address (0x00000000), but the entry point address depends on the 2600kernel version: 2601 2602- 2.2.x kernels have the entry point at 0x0000000C, 2603- 2.3.x and later kernels have the entry point at 0x00000000. 2604 2605So a typical call to build a U-Boot image would read: 2606 2607 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2608 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2609 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2610 > examples/uImage.TQM850L 2611 Image Name: 2.4.4 kernel for TQM850L 2612 Created: Wed Jul 19 02:34:59 2000 2613 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2614 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2615 Load Address: 0x00000000 2616 Entry Point: 0x00000000 2617 2618To verify the contents of the image (or check for corruption): 2619 2620 -> tools/mkimage -l examples/uImage.TQM850L 2621 Image Name: 2.4.4 kernel for TQM850L 2622 Created: Wed Jul 19 02:34:59 2000 2623 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2624 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2625 Load Address: 0x00000000 2626 Entry Point: 0x00000000 2627 2628NOTE: for embedded systems where boot time is critical you can trade 2629speed for memory and install an UNCOMPRESSED image instead: this 2630needs more space in Flash, but boots much faster since it does not 2631need to be uncompressed: 2632 2633 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2634 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2635 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2636 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2637 > examples/uImage.TQM850L-uncompressed 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 (uncompressed) 2641 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2642 Load Address: 0x00000000 2643 Entry Point: 0x00000000 2644 2645 2646Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2647when your kernel is intended to use an initial ramdisk: 2648 2649 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2650 > -A ppc -O linux -T ramdisk -C gzip \ 2651 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2652 Image Name: Simple Ramdisk Image 2653 Created: Wed Jan 12 14:01:50 2000 2654 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2655 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2656 Load Address: 0x00000000 2657 Entry Point: 0x00000000 2658 2659 2660Installing a Linux Image: 2661------------------------- 2662 2663To downloading a U-Boot image over the serial (console) interface, 2664you must convert the image to S-Record format: 2665 2666 objcopy -I binary -O srec examples/image examples/image.srec 2667 2668The 'objcopy' does not understand the information in the U-Boot 2669image header, so the resulting S-Record file will be relative to 2670address 0x00000000. To load it to a given address, you need to 2671specify the target address as 'offset' parameter with the 'loads' 2672command. 2673 2674Example: install the image to address 0x40100000 (which on the 2675TQM8xxL is in the first Flash bank): 2676 2677 => erase 40100000 401FFFFF 2678 2679 .......... done 2680 Erased 8 sectors 2681 2682 => loads 40100000 2683 ## Ready for S-Record download ... 2684 ~>examples/image.srec 2685 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2686 ... 2687 15989 15990 15991 15992 2688 [file transfer complete] 2689 [connected] 2690 ## Start Addr = 0x00000000 2691 2692 2693You can check the success of the download using the 'iminfo' command; 2694this includes a checksum verification so you can be sure no data 2695corruption happened: 2696 2697 => imi 40100000 2698 2699 ## Checking Image at 40100000 ... 2700 Image Name: 2.2.13 for initrd on TQM850L 2701 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2702 Data Size: 335725 Bytes = 327 kB = 0 MB 2703 Load Address: 00000000 2704 Entry Point: 0000000c 2705 Verifying Checksum ... OK 2706 2707 2708Boot Linux: 2709----------- 2710 2711The "bootm" command is used to boot an application that is stored in 2712memory (RAM or Flash). In case of a Linux kernel image, the contents 2713of the "bootargs" environment variable is passed to the kernel as 2714parameters. You can check and modify this variable using the 2715"printenv" and "setenv" commands: 2716 2717 2718 => printenv bootargs 2719 bootargs=root=/dev/ram 2720 2721 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2722 2723 => printenv bootargs 2724 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2725 2726 => bootm 40020000 2727 ## Booting Linux kernel at 40020000 ... 2728 Image Name: 2.2.13 for NFS on TQM850L 2729 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2730 Data Size: 381681 Bytes = 372 kB = 0 MB 2731 Load Address: 00000000 2732 Entry Point: 0000000c 2733 Verifying Checksum ... OK 2734 Uncompressing Kernel Image ... OK 2735 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 2736 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2737 time_init: decrementer frequency = 187500000/60 2738 Calibrating delay loop... 49.77 BogoMIPS 2739 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2740 ... 2741 2742If you want to boot a Linux kernel with initial ram disk, you pass 2743the memory addresses of both the kernel and the initrd image (PPBCOOT 2744format!) to the "bootm" command: 2745 2746 => imi 40100000 40200000 2747 2748 ## Checking Image at 40100000 ... 2749 Image Name: 2.2.13 for initrd on TQM850L 2750 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2751 Data Size: 335725 Bytes = 327 kB = 0 MB 2752 Load Address: 00000000 2753 Entry Point: 0000000c 2754 Verifying Checksum ... OK 2755 2756 ## Checking Image at 40200000 ... 2757 Image Name: Simple Ramdisk Image 2758 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2759 Data Size: 566530 Bytes = 553 kB = 0 MB 2760 Load Address: 00000000 2761 Entry Point: 00000000 2762 Verifying Checksum ... OK 2763 2764 => bootm 40100000 40200000 2765 ## Booting Linux kernel at 40100000 ... 2766 Image Name: 2.2.13 for initrd on TQM850L 2767 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2768 Data Size: 335725 Bytes = 327 kB = 0 MB 2769 Load Address: 00000000 2770 Entry Point: 0000000c 2771 Verifying Checksum ... OK 2772 Uncompressing Kernel Image ... OK 2773 ## Loading RAMDisk Image at 40200000 ... 2774 Image Name: Simple Ramdisk Image 2775 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2776 Data Size: 566530 Bytes = 553 kB = 0 MB 2777 Load Address: 00000000 2778 Entry Point: 00000000 2779 Verifying Checksum ... OK 2780 Loading Ramdisk ... OK 2781 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 2782 Boot arguments: root=/dev/ram 2783 time_init: decrementer frequency = 187500000/60 2784 Calibrating delay loop... 49.77 BogoMIPS 2785 ... 2786 RAMDISK: Compressed image found at block 0 2787 VFS: Mounted root (ext2 filesystem). 2788 2789 bash# 2790 2791More About U-Boot Image Types: 2792------------------------------ 2793 2794U-Boot supports the following image types: 2795 2796 "Standalone Programs" are directly runnable in the environment 2797 provided by U-Boot; it is expected that (if they behave 2798 well) you can continue to work in U-Boot after return from 2799 the Standalone Program. 2800 "OS Kernel Images" are usually images of some Embedded OS which 2801 will take over control completely. Usually these programs 2802 will install their own set of exception handlers, device 2803 drivers, set up the MMU, etc. - this means, that you cannot 2804 expect to re-enter U-Boot except by resetting the CPU. 2805 "RAMDisk Images" are more or less just data blocks, and their 2806 parameters (address, size) are passed to an OS kernel that is 2807 being started. 2808 "Multi-File Images" contain several images, typically an OS 2809 (Linux) kernel image and one or more data images like 2810 RAMDisks. This construct is useful for instance when you want 2811 to boot over the network using BOOTP etc., where the boot 2812 server provides just a single image file, but you want to get 2813 for instance an OS kernel and a RAMDisk image. 2814 2815 "Multi-File Images" start with a list of image sizes, each 2816 image size (in bytes) specified by an "uint32_t" in network 2817 byte order. This list is terminated by an "(uint32_t)0". 2818 Immediately after the terminating 0 follow the images, one by 2819 one, all aligned on "uint32_t" boundaries (size rounded up to 2820 a multiple of 4 bytes). 2821 2822 "Firmware Images" are binary images containing firmware (like 2823 U-Boot or FPGA images) which usually will be programmed to 2824 flash memory. 2825 2826 "Script files" are command sequences that will be executed by 2827 U-Boot's command interpreter; this feature is especially 2828 useful when you configure U-Boot to use a real shell (hush) 2829 as command interpreter. 2830 2831 2832Standalone HOWTO: 2833================= 2834 2835One of the features of U-Boot is that you can dynamically load and 2836run "standalone" applications, which can use some resources of 2837U-Boot like console I/O functions or interrupt services. 2838 2839Two simple examples are included with the sources: 2840 2841"Hello World" Demo: 2842------------------- 2843 2844'examples/hello_world.c' contains a small "Hello World" Demo 2845application; it is automatically compiled when you build U-Boot. 2846It's configured to run at address 0x00040004, so you can play with it 2847like that: 2848 2849 => loads 2850 ## Ready for S-Record download ... 2851 ~>examples/hello_world.srec 2852 1 2 3 4 5 6 7 8 9 10 11 ... 2853 [file transfer complete] 2854 [connected] 2855 ## Start Addr = 0x00040004 2856 2857 => go 40004 Hello World! This is a test. 2858 ## Starting application at 0x00040004 ... 2859 Hello World 2860 argc = 7 2861 argv[0] = "40004" 2862 argv[1] = "Hello" 2863 argv[2] = "World!" 2864 argv[3] = "This" 2865 argv[4] = "is" 2866 argv[5] = "a" 2867 argv[6] = "test." 2868 argv[7] = "<NULL>" 2869 Hit any key to exit ... 2870 2871 ## Application terminated, rc = 0x0 2872 2873Another example, which demonstrates how to register a CPM interrupt 2874handler with the U-Boot code, can be found in 'examples/timer.c'. 2875Here, a CPM timer is set up to generate an interrupt every second. 2876The interrupt service routine is trivial, just printing a '.' 2877character, but this is just a demo program. The application can be 2878controlled by the following keys: 2879 2880 ? - print current values og the CPM Timer registers 2881 b - enable interrupts and start timer 2882 e - stop timer and disable interrupts 2883 q - quit application 2884 2885 => loads 2886 ## Ready for S-Record download ... 2887 ~>examples/timer.srec 2888 1 2 3 4 5 6 7 8 9 10 11 ... 2889 [file transfer complete] 2890 [connected] 2891 ## Start Addr = 0x00040004 2892 2893 => go 40004 2894 ## Starting application at 0x00040004 ... 2895 TIMERS=0xfff00980 2896 Using timer 1 2897 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2898 2899Hit 'b': 2900 [q, b, e, ?] Set interval 1000000 us 2901 Enabling timer 2902Hit '?': 2903 [q, b, e, ?] ........ 2904 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2905Hit '?': 2906 [q, b, e, ?] . 2907 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2908Hit '?': 2909 [q, b, e, ?] . 2910 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2911Hit '?': 2912 [q, b, e, ?] . 2913 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2914Hit 'e': 2915 [q, b, e, ?] ...Stopping timer 2916Hit 'q': 2917 [q, b, e, ?] ## Application terminated, rc = 0x0 2918 2919 2920Minicom warning: 2921================ 2922 2923Over time, many people have reported problems when trying to use the 2924"minicom" terminal emulation program for serial download. I (wd) 2925consider minicom to be broken, and recommend not to use it. Under 2926Unix, I recommend to use C-Kermit for general purpose use (and 2927especially for kermit binary protocol download ("loadb" command), and 2928use "cu" for S-Record download ("loads" command). 2929 2930Nevertheless, if you absolutely want to use it try adding this 2931configuration to your "File transfer protocols" section: 2932 2933 Name Program Name U/D FullScr IO-Red. Multi 2934 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2935 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2936 2937 2938NetBSD Notes: 2939============= 2940 2941Starting at version 0.9.2, U-Boot supports NetBSD both as host 2942(build U-Boot) and target system (boots NetBSD/mpc8xx). 2943 2944Building requires a cross environment; it is known to work on 2945NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2946need gmake since the Makefiles are not compatible with BSD make). 2947Note that the cross-powerpc package does not install include files; 2948attempting to build U-Boot will fail because <machine/ansi.h> is 2949missing. This file has to be installed and patched manually: 2950 2951 # cd /usr/pkg/cross/powerpc-netbsd/include 2952 # mkdir powerpc 2953 # ln -s powerpc machine 2954 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2955 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2956 2957Native builds *don't* work due to incompatibilities between native 2958and U-Boot include files. 2959 2960Booting assumes that (the first part of) the image booted is a 2961stage-2 loader which in turn loads and then invokes the kernel 2962proper. Loader sources will eventually appear in the NetBSD source 2963tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2964meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2965details. 2966 2967 2968Implementation Internals: 2969========================= 2970 2971The following is not intended to be a complete description of every 2972implementation detail. However, it should help to understand the 2973inner workings of U-Boot and make it easier to port it to custom 2974hardware. 2975 2976 2977Initial Stack, Global Data: 2978--------------------------- 2979 2980The implementation of U-Boot is complicated by the fact that U-Boot 2981starts running out of ROM (flash memory), usually without access to 2982system RAM (because the memory controller is not initialized yet). 2983This means that we don't have writable Data or BSS segments, and BSS 2984is not initialized as zero. To be able to get a C environment working 2985at all, we have to allocate at least a minimal stack. Implementation 2986options for this are defined and restricted by the CPU used: Some CPU 2987models provide on-chip memory (like the IMMR area on MPC8xx and 2988MPC826x processors), on others (parts of) the data cache can be 2989locked as (mis-) used as memory, etc. 2990 2991 Chris Hallinan posted a good summary of these issues to the 2992 u-boot-users mailing list: 2993 2994 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 2995 From: "Chris Hallinan" <clh@net1plus.com> 2996 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 2997 ... 2998 2999 Correct me if I'm wrong, folks, but the way I understand it 3000 is this: Using DCACHE as initial RAM for Stack, etc, does not 3001 require any physical RAM backing up the cache. The cleverness 3002 is that the cache is being used as a temporary supply of 3003 necessary storage before the SDRAM controller is setup. It's 3004 beyond the scope of this list to expain the details, but you 3005 can see how this works by studying the cache architecture and 3006 operation in the architecture and processor-specific manuals. 3007 3008 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3009 is another option for the system designer to use as an 3010 initial stack/ram area prior to SDRAM being available. Either 3011 option should work for you. Using CS 4 should be fine if your 3012 board designers haven't used it for something that would 3013 cause you grief during the initial boot! It is frequently not 3014 used. 3015 3016 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3017 with your processor/board/system design. The default value 3018 you will find in any recent u-boot distribution in 3019 Walnut405.h should work for you. I'd set it to a value larger 3020 than your SDRAM module. If you have a 64MB SDRAM module, set 3021 it above 400_0000. Just make sure your board has no resources 3022 that are supposed to respond to that address! That code in 3023 start.S has been around a while and should work as is when 3024 you get the config right. 3025 3026 -Chris Hallinan 3027 DS4.COM, Inc. 3028 3029It is essential to remember this, since it has some impact on the C 3030code for the initialization procedures: 3031 3032* Initialized global data (data segment) is read-only. Do not attempt 3033 to write it. 3034 3035* Do not use any unitialized global data (or implicitely initialized 3036 as zero data - BSS segment) at all - this is undefined, initiali- 3037 zation is performed later (when relocating to RAM). 3038 3039* Stack space is very limited. Avoid big data buffers or things like 3040 that. 3041 3042Having only the stack as writable memory limits means we cannot use 3043normal global data to share information beween the code. But it 3044turned out that the implementation of U-Boot can be greatly 3045simplified by making a global data structure (gd_t) available to all 3046functions. We could pass a pointer to this data as argument to _all_ 3047functions, but this would bloat the code. Instead we use a feature of 3048the GCC compiler (Global Register Variables) to share the data: we 3049place a pointer (gd) to the global data into a register which we 3050reserve for this purpose. 3051 3052When choosing a register for such a purpose we are restricted by the 3053relevant (E)ABI specifications for the current architecture, and by 3054GCC's implementation. 3055 3056For PowerPC, the following registers have specific use: 3057 R1: stack pointer 3058 R2: TOC pointer 3059 R3-R4: parameter passing and return values 3060 R5-R10: parameter passing 3061 R13: small data area pointer 3062 R30: GOT pointer 3063 R31: frame pointer 3064 3065 (U-Boot also uses R14 as internal GOT pointer.) 3066 3067 ==> U-Boot will use R29 to hold a pointer to the global data 3068 3069 Note: on PPC, we could use a static initializer (since the 3070 address of the global data structure is known at compile time), 3071 but it turned out that reserving a register results in somewhat 3072 smaller code - although the code savings are not that big (on 3073 average for all boards 752 bytes for the whole U-Boot image, 3074 624 text + 127 data). 3075 3076On ARM, the following registers are used: 3077 3078 R0: function argument word/integer result 3079 R1-R3: function argument word 3080 R9: GOT pointer 3081 R10: stack limit (used only if stack checking if enabled) 3082 R11: argument (frame) pointer 3083 R12: temporary workspace 3084 R13: stack pointer 3085 R14: link register 3086 R15: program counter 3087 3088 ==> U-Boot will use R8 to hold a pointer to the global data 3089 3090 3091Memory Management: 3092------------------ 3093 3094U-Boot runs in system state and uses physical addresses, i.e. the 3095MMU is not used either for address mapping nor for memory protection. 3096 3097The available memory is mapped to fixed addresses using the memory 3098controller. In this process, a contiguous block is formed for each 3099memory type (Flash, SDRAM, SRAM), even when it consists of several 3100physical memory banks. 3101 3102U-Boot is installed in the first 128 kB of the first Flash bank (on 3103TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3104booting and sizing and initializing DRAM, the code relocates itself 3105to the upper end of DRAM. Immediately below the U-Boot code some 3106memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3107configuration setting]. Below that, a structure with global Board 3108Info data is placed, followed by the stack (growing downward). 3109 3110Additionally, some exception handler code is copied to the low 8 kB 3111of DRAM (0x00000000 ... 0x00001FFF). 3112 3113So a typical memory configuration with 16 MB of DRAM could look like 3114this: 3115 3116 0x0000 0000 Exception Vector code 3117 : 3118 0x0000 1FFF 3119 0x0000 2000 Free for Application Use 3120 : 3121 : 3122 3123 : 3124 : 3125 0x00FB FF20 Monitor Stack (Growing downward) 3126 0x00FB FFAC Board Info Data and permanent copy of global data 3127 0x00FC 0000 Malloc Arena 3128 : 3129 0x00FD FFFF 3130 0x00FE 0000 RAM Copy of Monitor Code 3131 ... eventually: LCD or video framebuffer 3132 ... eventually: pRAM (Protected RAM - unchanged by reset) 3133 0x00FF FFFF [End of RAM] 3134 3135 3136System Initialization: 3137---------------------- 3138 3139In the reset configuration, U-Boot starts at the reset entry point 3140(on most PowerPC systens at address 0x00000100). Because of the reset 3141configuration for CS0# this is a mirror of the onboard Flash memory. 3142To be able to re-map memory U-Boot then jumps to its link address. 3143To be able to implement the initialization code in C, a (small!) 3144initial stack is set up in the internal Dual Ported RAM (in case CPUs 3145which provide such a feature like MPC8xx or MPC8260), or in a locked 3146part of the data cache. After that, U-Boot initializes the CPU core, 3147the caches and the SIU. 3148 3149Next, all (potentially) available memory banks are mapped using a 3150preliminary mapping. For example, we put them on 512 MB boundaries 3151(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3152on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3153programmed for SDRAM access. Using the temporary configuration, a 3154simple memory test is run that determines the size of the SDRAM 3155banks. 3156 3157When there is more than one SDRAM bank, and the banks are of 3158different size, the largest is mapped first. For equal size, the first 3159bank (CS2#) is mapped first. The first mapping is always for address 31600x00000000, with any additional banks following immediately to create 3161contiguous memory starting from 0. 3162 3163Then, the monitor installs itself at the upper end of the SDRAM area 3164and allocates memory for use by malloc() and for the global Board 3165Info data; also, the exception vector code is copied to the low RAM 3166pages, and the final stack is set up. 3167 3168Only after this relocation will you have a "normal" C environment; 3169until that you are restricted in several ways, mostly because you are 3170running from ROM, and because the code will have to be relocated to a 3171new address in RAM. 3172 3173 3174U-Boot Porting Guide: 3175---------------------- 3176 3177[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3178list, October 2002] 3179 3180 3181int main (int argc, char *argv[]) 3182{ 3183 sighandler_t no_more_time; 3184 3185 signal (SIGALRM, no_more_time); 3186 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3187 3188 if (available_money > available_manpower) { 3189 pay consultant to port U-Boot; 3190 return 0; 3191 } 3192 3193 Download latest U-Boot source; 3194 3195 Subscribe to u-boot-users mailing list; 3196 3197 if (clueless) { 3198 email ("Hi, I am new to U-Boot, how do I get started?"); 3199 } 3200 3201 while (learning) { 3202 Read the README file in the top level directory; 3203 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3204 Read the source, Luke; 3205 } 3206 3207 if (available_money > toLocalCurrency ($2500)) { 3208 Buy a BDI2000; 3209 } else { 3210 Add a lot of aggravation and time; 3211 } 3212 3213 Create your own board support subdirectory; 3214 3215 Create your own board config file; 3216 3217 while (!running) { 3218 do { 3219 Add / modify source code; 3220 } until (compiles); 3221 Debug; 3222 if (clueless) 3223 email ("Hi, I am having problems..."); 3224 } 3225 Send patch file to Wolfgang; 3226 3227 return 0; 3228} 3229 3230void no_more_time (int sig) 3231{ 3232 hire_a_guru(); 3233} 3234 3235 3236Coding Standards: 3237----------------- 3238 3239All contributions to U-Boot should conform to the Linux kernel 3240coding style; see the file "Documentation/CodingStyle" in your Linux 3241kernel source directory. 3242 3243Please note that U-Boot is implemented in C (and to some small parts 3244in Assembler); no C++ is used, so please do not use C++ style 3245comments (//) in your code. 3246 3247Please also stick to the following formatting rules: 3248- remove any trailing white space 3249- use TAB characters for indentation, not spaces 3250- make sure NOT to use DOS '\r\n' line feeds 3251- do not add more than 2 empty lines to source files 3252- do not add trailing empty lines to source files 3253 3254Submissions which do not conform to the standards may be returned 3255with a request to reformat the changes. 3256 3257 3258Submitting Patches: 3259------------------- 3260 3261Since the number of patches for U-Boot is growing, we need to 3262establish some rules. Submissions which do not conform to these rules 3263may be rejected, even when they contain important and valuable stuff. 3264 3265 3266When you send a patch, please include the following information with 3267it: 3268 3269* For bug fixes: a description of the bug and how your patch fixes 3270 this bug. Please try to include a way of demonstrating that the 3271 patch actually fixes something. 3272 3273* For new features: a description of the feature and your 3274 implementation. 3275 3276* A CHANGELOG entry as plaintext (separate from the patch) 3277 3278* For major contributions, your entry to the CREDITS file 3279 3280* When you add support for a new board, don't forget to add this 3281 board to the MAKEALL script, too. 3282 3283* If your patch adds new configuration options, don't forget to 3284 document these in the README file. 3285 3286* The patch itself. If you are accessing the CVS repository use "cvs 3287 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3288 version of diff does not support these options, then get the latest 3289 version of GNU diff. 3290 3291 The current directory when running this command shall be the top 3292 level directory of the U-Boot source tree, or it's parent directory 3293 (i. e. please make sure that your patch includes sufficient 3294 directory information for the affected files). 3295 3296 We accept patches as plain text, MIME attachments or as uuencoded 3297 gzipped text. 3298 3299* If one logical set of modifications affects or creates several 3300 files, all these changes shall be submitted in a SINGLE patch file. 3301 3302* Changesets that contain different, unrelated modifications shall be 3303 submitted as SEPARATE patches, one patch per changeset. 3304 3305 3306Notes: 3307 3308* Before sending the patch, run the MAKEALL script on your patched 3309 source tree and make sure that no errors or warnings are reported 3310 for any of the boards. 3311 3312* Keep your modifications to the necessary minimum: A patch 3313 containing several unrelated changes or arbitrary reformats will be 3314 returned with a request to re-formatting / split it. 3315 3316* If you modify existing code, make sure that your new code does not 3317 add to the memory footprint of the code ;-) Small is beautiful! 3318 When adding new features, these should compile conditionally only 3319 (using #ifdef), and the resulting code with the new feature 3320 disabled must not need more memory than the old code without your 3321 modification. 3322