1# 2# (C) Copyright 2000 - 2002 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- disk Code for disk drive partition handling 126- doc Documentation (don't expect too much) 127- drivers Commonly used device drivers 128- dtt Digital Thermometer and Thermostat drivers 129- examples Example code for standalone applications, etc. 130- include Header Files 131- disk Harddisk interface code 132- net Networking code 133- ppc Files generic to PowerPC architecture 134- post Power On Self Test 135- post/arch Symlink to architecture specific Power On Self Test 136- post/arch-ppc PowerPC architecture specific Power On Self Test 137- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test 138- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test 139- rtc Real Time Clock drivers 140- tools Tools to build S-Record or U-Boot images, etc. 141 142- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 143- cpu/arm925t Files specific to ARM 925 CPUs 144- cpu/arm926ejs Files specific to ARM 926 CPUs 145- cpu/mpc5xx Files specific to Motorola MPC5xx CPUs 146- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs 147- cpu/mpc824x Files specific to Motorola MPC824x CPUs 148- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 149- cpu/ppc4xx Files specific to IBM 4xx CPUs 150 151 152- board/LEOX/ Files specific to boards manufactured by The LEOX team 153- board/LEOX/elpt860 Files specific to ELPT860 boards 154- board/RPXClassic 155 Files specific to RPXClassic boards 156- board/RPXlite Files specific to RPXlite boards 157- board/at91rm9200dk Files specific to AT91RM9200DK boards 158- board/c2mon Files specific to c2mon boards 159- board/cmi Files specific to cmi boards 160- board/cogent Files specific to Cogent boards 161 (need further configuration) 162 Files specific to CPCIISER4 boards 163- board/cpu86 Files specific to CPU86 boards 164- board/cray/ Files specific to boards manufactured by Cray 165- board/cray/L1 Files specific to L1 boards 166- board/cu824 Files specific to CU824 boards 167- board/ebony Files specific to IBM Ebony board 168- board/eric Files specific to ERIC boards 169- board/esd/ Files specific to boards manufactured by ESD 170- board/esd/adciop Files specific to ADCIOP boards 171- board/esd/ar405 Files specific to AR405 boards 172- board/esd/canbt Files specific to CANBT boards 173- board/esd/cpci405 Files specific to CPCI405 boards 174- board/esd/cpciiser4 Files specific to CPCIISER4 boards 175- board/esd/common Common files for ESD boards 176- board/esd/dasa_sim Files specific to DASA_SIM boards 177- board/esd/du405 Files specific to DU405 boards 178- board/esd/ocrtc Files specific to OCRTC boards 179- board/esd/pci405 Files specific to PCI405 boards 180- board/esteem192e 181 Files specific to ESTEEM192E boards 182- board/etx094 Files specific to ETX_094 boards 183- board/evb64260 184 Files specific to EVB64260 boards 185- board/fads Files specific to FADS boards 186- board/flagadm Files specific to FLAGADM boards 187- board/gen860t Files specific to GEN860T and GEN860T_SC boards 188- board/genietv Files specific to GENIETV boards 189- board/gth Files specific to GTH boards 190- board/hermes Files specific to HERMES boards 191- board/hymod Files specific to HYMOD boards 192- board/icu862 Files specific to ICU862 boards 193- board/ip860 Files specific to IP860 boards 194- board/iphase4539 195 Files specific to Interphase4539 boards 196- board/ivm Files specific to IVMS8/IVML24 boards 197- board/lantec Files specific to LANTEC boards 198- board/lwmon Files specific to LWMON boards 199- board/mbx8xx Files specific to MBX boards 200- board/mpc8260ads 201 Files specific to MPC8260ADS and PQ2FADS-ZU boards 202- board/mpl/ Files specific to boards manufactured by MPL 203- board/mpl/common Common files for MPL boards 204- board/mpl/pip405 Files specific to PIP405 boards 205- board/mpl/mip405 Files specific to MIP405 boards 206- board/mpl/vcma9 Files specific to VCMA9 boards 207- board/musenki Files specific to MUSEKNI boards 208- board/mvs1 Files specific to MVS1 boards 209- board/nx823 Files specific to NX823 boards 210- board/oxc Files specific to OXC boards 211- board/omap1510inn 212 Files specific to OMAP 1510 Innovator boards 213- board/omap1610inn 214 Files specific to OMAP 1610 Innovator boards 215- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 216- board/pm826 Files specific to PM826 boards 217- board/ppmc8260 218 Files specific to PPMC8260 boards 219- board/rpxsuper 220 Files specific to RPXsuper boards 221- board/rsdproto 222 Files specific to RSDproto boards 223- board/sandpoint 224 Files specific to Sandpoint boards 225- board/sbc8260 Files specific to SBC8260 boards 226- board/sacsng Files specific to SACSng boards 227- board/siemens Files specific to boards manufactured by Siemens AG 228- board/siemens/CCM Files specific to CCM boards 229- board/siemens/IAD210 Files specific to IAD210 boards 230- board/siemens/SCM Files specific to SCM boards 231- board/siemens/pcu_e Files specific to PCU_E boards 232- board/sixnet Files specific to SIXNET boards 233- board/spd8xx Files specific to SPD8xxTS boards 234- board/tqm8260 Files specific to TQM8260 boards 235- board/tqm8xx Files specific to TQM8xxL boards 236- board/w7o Files specific to W7O boards 237- board/walnut405 238 Files specific to Walnut405 boards 239- board/westel/ Files specific to boards manufactured by Westel Wireless 240- board/westel/amx860 Files specific to AMX860 boards 241- board/utx8245 Files specific to UTX8245 boards 242 243Software Configuration: 244======================= 245 246Configuration is usually done using C preprocessor defines; the 247rationale behind that is to avoid dead code whenever possible. 248 249There are two classes of configuration variables: 250 251* Configuration _OPTIONS_: 252 These are selectable by the user and have names beginning with 253 "CONFIG_". 254 255* Configuration _SETTINGS_: 256 These depend on the hardware etc. and should not be meddled with if 257 you don't know what you're doing; they have names beginning with 258 "CFG_". 259 260Later we will add a configuration tool - probably similar to or even 261identical to what's used for the Linux kernel. Right now, we have to 262do the configuration by hand, which means creating some symbolic 263links and editing some configuration files. We use the TQM8xxL boards 264as an example here. 265 266 267Selection of Processor Architecture and Board Type: 268--------------------------------------------------- 269 270For all supported boards there are ready-to-use default 271configurations available; just type "make <board_name>_config". 272 273Example: For a TQM823L module type: 274 275 cd u-boot 276 make TQM823L_config 277 278For the Cogent platform, you need to specify the cpu type as well; 279e.g. "make cogent_mpc8xx_config". And also configure the cogent 280directory according to the instructions in cogent/README. 281 282 283Configuration Options: 284---------------------- 285 286Configuration depends on the combination of board and CPU type; all 287such information is kept in a configuration file 288"include/configs/<board_name>.h". 289 290Example: For a TQM823L module, all configuration settings are in 291"include/configs/TQM823L.h". 292 293 294Many of the options are named exactly as the corresponding Linux 295kernel configuration options. The intention is to make it easier to 296build a config tool - later. 297 298 299The following options need to be configured: 300 301- CPU Type: Define exactly one of 302 303 PowerPC based CPUs: 304 ------------------- 305 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 306 or CONFIG_MPC5xx 307 or CONFIG_MPC824X, CONFIG_MPC8260 308 or CONFIG_IOP480 309 or CONFIG_405GP 310 or CONFIG_405EP 311 or CONFIG_440 312 or CONFIG_MPC74xx 313 or CONFIG_750FX 314 315 ARM based CPUs: 316 --------------- 317 CONFIG_SA1110 318 CONFIG_ARM7 319 CONFIG_PXA250 320 321 322- Board Type: Define exactly one of 323 324 PowerPC based boards: 325 --------------------- 326 327 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 328 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 329 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 330 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 331 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 332 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 333 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 334 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 335 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 336 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 337 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 338 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 339 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 340 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 341 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 342 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 343 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 344 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 345 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 346 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 347 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 348 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 349 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 350 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 351 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 352 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 353 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 354 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 355 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 356 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L, 357 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI, 358 CONFIG_NETVIA, CONFIG_RBC823 359 360 ARM based boards: 361 ----------------- 362 363 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 364 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 365 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610 366 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 367 CONFIG_TRAB, CONFIG_VCMA9, CONFIG_AT91RM9200DK 368 369 370- CPU Module Type: (if CONFIG_COGENT is defined) 371 Define exactly one of 372 CONFIG_CMA286_60_OLD 373--- FIXME --- not tested yet: 374 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 375 CONFIG_CMA287_23, CONFIG_CMA287_50 376 377- Motherboard Type: (if CONFIG_COGENT is defined) 378 Define exactly one of 379 CONFIG_CMA101, CONFIG_CMA102 380 381- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 382 Define one or more of 383 CONFIG_CMA302 384 385- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 386 Define one or more of 387 CONFIG_LCD_HEARTBEAT - update a character position on 388 the lcd display every second with 389 a "rotator" |\-/|\-/ 390 391- Board flavour: (if CONFIG_MPC8260ADS is defined) 392 CONFIG_ADSTYPE 393 Possible values are: 394 CFG_8260ADS - original MPC8260ADS 395 CFG_8266ADS - MPC8266ADS (untested) 396 CFG_PQ2FADS - PQ2FADS-ZU 397 398 399- MPC824X Family Member (if CONFIG_MPC824X is defined) 400 Define exactly one of 401 CONFIG_MPC8240, CONFIG_MPC8245 402 403- 8xx CPU Options: (if using an 8xx cpu) 404 Define one or more of 405 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 406 no 32KHz reference PIT/RTC clock 407 408- Clock Interface: 409 CONFIG_CLOCKS_IN_MHZ 410 411 U-Boot stores all clock information in Hz 412 internally. For binary compatibility with older Linux 413 kernels (which expect the clocks passed in the 414 bd_info data to be in MHz) the environment variable 415 "clocks_in_mhz" can be defined so that U-Boot 416 converts clock data to MHZ before passing it to the 417 Linux kernel. 418 419 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 420 "clocks_in_mhz=1" is automatically included in the 421 default environment. 422 423- Console Interface: 424 Depending on board, define exactly one serial port 425 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 426 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 427 console by defining CONFIG_8xx_CONS_NONE 428 429 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 430 port routines must be defined elsewhere 431 (i.e. serial_init(), serial_getc(), ...) 432 433 CONFIG_CFB_CONSOLE 434 Enables console device for a color framebuffer. Needs following 435 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 436 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 437 (default big endian) 438 VIDEO_HW_RECTFILL graphic chip supports 439 rectangle fill 440 (cf. smiLynxEM) 441 VIDEO_HW_BITBLT graphic chip supports 442 bit-blit (cf. smiLynxEM) 443 VIDEO_VISIBLE_COLS visible pixel columns 444 (cols=pitch) 445 VIDEO_VISIBLE_ROWS visible pixel rows 446 VIDEO_PIXEL_SIZE bytes per pixel 447 VIDEO_DATA_FORMAT graphic data format 448 (0-5, cf. cfb_console.c) 449 VIDEO_FB_ADRS framebuffer address 450 VIDEO_KBD_INIT_FCT keyboard int fct 451 (i.e. i8042_kbd_init()) 452 VIDEO_TSTC_FCT test char fct 453 (i.e. i8042_tstc) 454 VIDEO_GETC_FCT get char fct 455 (i.e. i8042_getc) 456 CONFIG_CONSOLE_CURSOR cursor drawing on/off 457 (requires blink timer 458 cf. i8042.c) 459 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 460 CONFIG_CONSOLE_TIME display time/date info in 461 upper right corner 462 (requires CFG_CMD_DATE) 463 CONFIG_VIDEO_LOGO display Linux logo in 464 upper left corner 465 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 466 linux_logo.h for logo. 467 Requires CONFIG_VIDEO_LOGO 468 CONFIG_CONSOLE_EXTRA_INFO 469 addional board info beside 470 the logo 471 472 When CONFIG_CFB_CONSOLE is defined, video console is 473 default i/o. Serial console can be forced with 474 environment 'console=serial'. 475 476- Console Baudrate: 477 CONFIG_BAUDRATE - in bps 478 Select one of the baudrates listed in 479 CFG_BAUDRATE_TABLE, see below. 480 481- Interrupt driven serial port input: 482 CONFIG_SERIAL_SOFTWARE_FIFO 483 484 PPC405GP only. 485 Use an interrupt handler for receiving data on the 486 serial port. It also enables using hardware handshake 487 (RTS/CTS) and UART's built-in FIFO. Set the number of 488 bytes the interrupt driven input buffer should have. 489 490 Set to 0 to disable this feature (this is the default). 491 This will also disable hardware handshake. 492 493- Console UART Number: 494 CONFIG_UART1_CONSOLE 495 496 IBM PPC4xx only. 497 If defined internal UART1 (and not UART0) is used 498 as default U-Boot console. 499 500- Boot Delay: CONFIG_BOOTDELAY - in seconds 501 Delay before automatically booting the default image; 502 set to -1 to disable autoboot. 503 504 See doc/README.autoboot for these options that 505 work with CONFIG_BOOTDELAY. None are required. 506 CONFIG_BOOT_RETRY_TIME 507 CONFIG_BOOT_RETRY_MIN 508 CONFIG_AUTOBOOT_KEYED 509 CONFIG_AUTOBOOT_PROMPT 510 CONFIG_AUTOBOOT_DELAY_STR 511 CONFIG_AUTOBOOT_STOP_STR 512 CONFIG_AUTOBOOT_DELAY_STR2 513 CONFIG_AUTOBOOT_STOP_STR2 514 CONFIG_ZERO_BOOTDELAY_CHECK 515 CONFIG_RESET_TO_RETRY 516 517- Autoboot Command: 518 CONFIG_BOOTCOMMAND 519 Only needed when CONFIG_BOOTDELAY is enabled; 520 define a command string that is automatically executed 521 when no character is read on the console interface 522 within "Boot Delay" after reset. 523 524 CONFIG_BOOTARGS 525 This can be used to pass arguments to the bootm 526 command. The value of CONFIG_BOOTARGS goes into the 527 environment value "bootargs". 528 529 CONFIG_RAMBOOT and CONFIG_NFSBOOT 530 The value of these goes into the environment as 531 "ramboot" and "nfsboot" respectively, and can be used 532 as a convenience, when switching between booting from 533 ram and nfs. 534 535- Pre-Boot Commands: 536 CONFIG_PREBOOT 537 538 When this option is #defined, the existence of the 539 environment variable "preboot" will be checked 540 immediately before starting the CONFIG_BOOTDELAY 541 countdown and/or running the auto-boot command resp. 542 entering interactive mode. 543 544 This feature is especially useful when "preboot" is 545 automatically generated or modified. For an example 546 see the LWMON board specific code: here "preboot" is 547 modified when the user holds down a certain 548 combination of keys on the (special) keyboard when 549 booting the systems 550 551- Serial Download Echo Mode: 552 CONFIG_LOADS_ECHO 553 If defined to 1, all characters received during a 554 serial download (using the "loads" command) are 555 echoed back. This might be needed by some terminal 556 emulations (like "cu"), but may as well just take 557 time on others. This setting #define's the initial 558 value of the "loads_echo" environment variable. 559 560- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 561 CONFIG_KGDB_BAUDRATE 562 Select one of the baudrates listed in 563 CFG_BAUDRATE_TABLE, see below. 564 565- Monitor Functions: 566 CONFIG_COMMANDS 567 Most monitor functions can be selected (or 568 de-selected) by adjusting the definition of 569 CONFIG_COMMANDS; to select individual functions, 570 #define CONFIG_COMMANDS by "OR"ing any of the 571 following values: 572 573 #define enables commands: 574 ------------------------- 575 CFG_CMD_ASKENV * ask for env variable 576 CFG_CMD_BDI bdinfo 577 CFG_CMD_BEDBUG Include BedBug Debugger 578 CFG_CMD_BOOTD bootd 579 CFG_CMD_CACHE icache, dcache 580 CFG_CMD_CONSOLE coninfo 581 CFG_CMD_DATE * support for RTC, date/time... 582 CFG_CMD_DHCP DHCP support 583 CFG_CMD_ECHO * echo arguments 584 CFG_CMD_EEPROM * EEPROM read/write support 585 CFG_CMD_ELF bootelf, bootvx 586 CFG_CMD_ENV saveenv 587 CFG_CMD_FDC * Floppy Disk Support 588 CFG_CMD_FAT FAT partition support 589 CFG_CMD_FDOS * Dos diskette Support 590 CFG_CMD_FLASH flinfo, erase, protect 591 CFG_CMD_FPGA FPGA device initialization support 592 CFG_CMD_I2C * I2C serial bus support 593 CFG_CMD_IDE * IDE harddisk support 594 CFG_CMD_IMI iminfo 595 CFG_CMD_IMMAP * IMMR dump support 596 CFG_CMD_IRQ * irqinfo 597 CFG_CMD_KGDB * kgdb 598 CFG_CMD_LOADB loadb 599 CFG_CMD_LOADS loads 600 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 601 loop, mtest 602 CFG_CMD_MMC MMC memory mapped support 603 CFG_CMD_MII MII utility commands 604 CFG_CMD_NET bootp, tftpboot, rarpboot 605 CFG_CMD_PCI * pciinfo 606 CFG_CMD_PCMCIA * PCMCIA support 607 CFG_CMD_REGINFO * Register dump 608 CFG_CMD_RUN run command in env variable 609 CFG_CMD_SCSI * SCSI Support 610 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 611 CFG_CMD_SPI * SPI serial bus support 612 CFG_CMD_USB * USB support 613 CFG_CMD_BSP * Board SPecific functions 614 ----------------------------------------------- 615 CFG_CMD_ALL all 616 617 CFG_CMD_DFL Default configuration; at the moment 618 this is includes all commands, except 619 the ones marked with "*" in the list 620 above. 621 622 If you don't define CONFIG_COMMANDS it defaults to 623 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 624 override the default settings in the respective 625 include file. 626 627 EXAMPLE: If you want all functions except of network 628 support you can write: 629 630 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 631 632 633 Note: Don't enable the "icache" and "dcache" commands 634 (configuration option CFG_CMD_CACHE) unless you know 635 what you (and your U-Boot users) are doing. Data 636 cache cannot be enabled on systems like the 8xx or 637 8260 (where accesses to the IMMR region must be 638 uncached), and it cannot be disabled on all other 639 systems where we (mis-) use the data cache to hold an 640 initial stack and some data. 641 642 643 XXX - this list needs to get updated! 644 645- Watchdog: 646 CONFIG_WATCHDOG 647 If this variable is defined, it enables watchdog 648 support. There must be support in the platform specific 649 code for a watchdog. For the 8xx and 8260 CPUs, the 650 SIU Watchdog feature is enabled in the SYPCR 651 register. 652 653- U-Boot Version: 654 CONFIG_VERSION_VARIABLE 655 If this variable is defined, an environment variable 656 named "ver" is created by U-Boot showing the U-Boot 657 version as printed by the "version" command. 658 This variable is readonly. 659 660- Real-Time Clock: 661 662 When CFG_CMD_DATE is selected, the type of the RTC 663 has to be selected, too. Define exactly one of the 664 following options: 665 666 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 667 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 668 CONFIG_RTC_MC146818 - use MC146818 RTC 669 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 670 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 671 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 672 CONFIG_RTC_DS164x - use Dallas DS164x RTC 673 674 Note that if the RTC uses I2C, then the I2C interface 675 must also be configured. See I2C Support, below. 676 677- Timestamp Support: 678 679 When CONFIG_TIMESTAMP is selected, the timestamp 680 (date and time) of an image is printed by image 681 commands like bootm or iminfo. This option is 682 automatically enabled when you select CFG_CMD_DATE . 683 684- Partition Support: 685 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 686 and/or CONFIG_ISO_PARTITION 687 688 If IDE or SCSI support is enabled (CFG_CMD_IDE or 689 CFG_CMD_SCSI) you must configure support for at least 690 one partition type as well. 691 692- IDE Reset method: 693 CONFIG_IDE_RESET_ROUTINE 694 695 Set this to define that instead of a reset Pin, the 696 routine ide_set_reset(int idereset) will be used. 697 698- ATAPI Support: 699 CONFIG_ATAPI 700 701 Set this to enable ATAPI support. 702 703- SCSI Support: 704 At the moment only there is only support for the 705 SYM53C8XX SCSI controller; define 706 CONFIG_SCSI_SYM53C8XX to enable it. 707 708 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 709 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 710 CFG_SCSI_MAX_LUN] can be adjusted to define the 711 maximum numbers of LUNs, SCSI ID's and target 712 devices. 713 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 714 715- NETWORK Support (PCI): 716 CONFIG_E1000 717 Support for Intel 8254x gigabit chips. 718 719 CONFIG_EEPRO100 720 Support for Intel 82557/82559/82559ER chips. 721 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 722 write routine for first time initialisation. 723 724 CONFIG_TULIP 725 Support for Digital 2114x chips. 726 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 727 modem chip initialisation (KS8761/QS6611). 728 729 CONFIG_NATSEMI 730 Support for National dp83815 chips. 731 732 CONFIG_NS8382X 733 Support for National dp8382[01] gigabit chips. 734 735- NETWORK Support (other): 736 737 CONFIG_DRIVER_LAN91C96 738 Support for SMSC's LAN91C96 chips. 739 740 CONFIG_LAN91C96_BASE 741 Define this to hold the physical address 742 of the LAN91C96's I/O space 743 744 CONFIG_LAN91C96_USE_32_BIT 745 Define this to enable 32 bit addressing 746 747- USB Support: 748 At the moment only the UHCI host controller is 749 supported (PIP405, MIP405); define 750 CONFIG_USB_UHCI to enable it. 751 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 752 end define CONFIG_USB_STORAGE to enable the USB 753 storage devices. 754 Note: 755 Supported are USB Keyboards and USB Floppy drives 756 (TEAC FD-05PUB). 757 758- MMC Support: 759 The MMC controller on the Intel PXA is supported. To 760 enable this define CONFIG_MMC. The MMC can be 761 accessed from the boot prompt by mapping the device 762 to physical memory similar to flash. Command line is 763 enabled with CFG_CMD_MMC. The MMC driver also works with 764 the FAT fs. This is enabled with CFG_CMD_FAT. 765 766- Keyboard Support: 767 CONFIG_ISA_KEYBOARD 768 769 Define this to enable standard (PC-Style) keyboard 770 support 771 772 CONFIG_I8042_KBD 773 Standard PC keyboard driver with US (is default) and 774 GERMAN key layout (switch via environment 'keymap=de') support. 775 Export function i8042_kbd_init, i8042_tstc and i8042_getc 776 for cfb_console. Supports cursor blinking. 777 778- Video support: 779 CONFIG_VIDEO 780 781 Define this to enable video support (for output to 782 video). 783 784 CONFIG_VIDEO_CT69000 785 786 Enable Chips & Technologies 69000 Video chip 787 788 CONFIG_VIDEO_SMI_LYNXEM 789 Enable Silicon Motion SMI 712/710/810 Video chip 790 Videomode are selected via environment 'videomode' with 791 standard LiLo mode numbers. 792 Following modes are supported (* is default): 793 794 800x600 1024x768 1280x1024 795 256 (8bit) 303* 305 307 796 65536 (16bit) 314 317 31a 797 16,7 Mill (24bit) 315 318 31b 798 (i.e. setenv videomode 317; saveenv; reset;) 799 800 CONFIG_VIDEO_SED13806 801 Enable Epson SED13806 driver. This driver supports 8bpp 802 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 803 or CONFIG_VIDEO_SED13806_16BPP 804 805- Keyboard Support: 806 CONFIG_KEYBOARD 807 808 Define this to enable a custom keyboard support. 809 This simply calls drv_keyboard_init() which must be 810 defined in your board-specific files. 811 The only board using this so far is RBC823. 812 813- LCD Support: CONFIG_LCD 814 815 Define this to enable LCD support (for output to LCD 816 display); also select one of the supported displays 817 by defining one of these: 818 819 CONFIG_NEC_NL6648AC33: 820 821 NEC NL6648AC33-18. Active, color, single scan. 822 823 CONFIG_NEC_NL6648BC20 824 825 NEC NL6648BC20-08. 6.5", 640x480. 826 Active, color, single scan. 827 828 CONFIG_SHARP_16x9 829 830 Sharp 320x240. Active, color, single scan. 831 It isn't 16x9, and I am not sure what it is. 832 833 CONFIG_SHARP_LQ64D341 834 835 Sharp LQ64D341 display, 640x480. 836 Active, color, single scan. 837 838 CONFIG_HLD1045 839 840 HLD1045 display, 640x480. 841 Active, color, single scan. 842 843 CONFIG_OPTREX_BW 844 845 Optrex CBL50840-2 NF-FW 99 22 M5 846 or 847 Hitachi LMG6912RPFC-00T 848 or 849 Hitachi SP14Q002 850 851 320x240. Black & white. 852 853 Normally display is black on white background; define 854 CFG_WHITE_ON_BLACK to get it inverted. 855 856- Splash Screen Support: CONFIG_SPLASH_SCREEN 857 858 If this option is set, the environment is checked for 859 a variable "splashimage". If found, the usual display 860 of logo, copyright and system information on the LCD 861 is supressed and the BMP image at the address 862 specified in "splashimage" is loaded instead. The 863 console is redirected to the "nulldev", too. This 864 allows for a "silent" boot where a splash screen is 865 loaded very quickly after power-on. 866 867- Compression support: 868 CONFIG_BZIP2 869 870 If this option is set, support for bzip2 compressed 871 images is included. If not, only uncompressed and gzip 872 compressed images are supported. 873 874 NOTE: the bzip2 algorithm requires a lot of RAM, so 875 the malloc area (as defined by CFG_MALLOC_LEN) should 876 be at least 4MB. 877 878- Ethernet address: 879 CONFIG_ETHADDR 880 CONFIG_ETH2ADDR 881 CONFIG_ETH3ADDR 882 883 Define a default value for ethernet address to use 884 for the respective ethernet interface, in case this 885 is not determined automatically. 886 887- IP address: 888 CONFIG_IPADDR 889 890 Define a default value for the IP address to use for 891 the default ethernet interface, in case this is not 892 determined through e.g. bootp. 893 894- Server IP address: 895 CONFIG_SERVERIP 896 897 Defines a default value for theIP address of a TFTP 898 server to contact when using the "tftboot" command. 899 900- BOOTP Recovery Mode: 901 CONFIG_BOOTP_RANDOM_DELAY 902 903 If you have many targets in a network that try to 904 boot using BOOTP, you may want to avoid that all 905 systems send out BOOTP requests at precisely the same 906 moment (which would happen for instance at recovery 907 from a power failure, when all systems will try to 908 boot, thus flooding the BOOTP server. Defining 909 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 910 inserted before sending out BOOTP requests. The 911 following delays are insterted then: 912 913 1st BOOTP request: delay 0 ... 1 sec 914 2nd BOOTP request: delay 0 ... 2 sec 915 3rd BOOTP request: delay 0 ... 4 sec 916 4th and following 917 BOOTP requests: delay 0 ... 8 sec 918 919- DHCP Advanced Options: 920 CONFIG_BOOTP_MASK 921 922 You can fine tune the DHCP functionality by adding 923 these flags to the CONFIG_BOOTP_MASK define: 924 925 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 926 serverip from a DHCP server, it is possible that more 927 than one DNS serverip is offered to the client. 928 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 929 serverip will be stored in the additional environment 930 variable "dnsip2". The first DNS serverip is always 931 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 932 is added to the CONFIG_BOOTP_MASK. 933 934 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 935 to do a dynamic update of a DNS server. To do this, they 936 need the hostname of the DHCP requester. 937 If CONFIG_BOOP_SEND_HOSTNAME is added to the 938 CONFIG_BOOTP_MASK, the content of the "hostname" 939 environment variable is passed as option 12 to 940 the DHCP server. 941 942- Status LED: CONFIG_STATUS_LED 943 944 Several configurations allow to display the current 945 status using a LED. For instance, the LED will blink 946 fast while running U-Boot code, stop blinking as 947 soon as a reply to a BOOTP request was received, and 948 start blinking slow once the Linux kernel is running 949 (supported by a status LED driver in the Linux 950 kernel). Defining CONFIG_STATUS_LED enables this 951 feature in U-Boot. 952 953- CAN Support: CONFIG_CAN_DRIVER 954 955 Defining CONFIG_CAN_DRIVER enables CAN driver support 956 on those systems that support this (optional) 957 feature, like the TQM8xxL modules. 958 959- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 960 961 These enable I2C serial bus commands. Defining either of 962 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 963 include the appropriate I2C driver for the selected cpu. 964 965 This will allow you to use i2c commands at the u-boot 966 command line (as long as you set CFG_CMD_I2C in 967 CONFIG_COMMANDS) and communicate with i2c based realtime 968 clock chips. See common/cmd_i2c.c for a description of the 969 command line interface. 970 971 CONFIG_HARD_I2C selects the CPM hardware driver for I2C. 972 973 CONFIG_SOFT_I2C configures u-boot to use a software (aka 974 bit-banging) driver instead of CPM or similar hardware 975 support for I2C. 976 977 There are several other quantities that must also be 978 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 979 980 In both cases you will need to define CFG_I2C_SPEED 981 to be the frequency (in Hz) at which you wish your i2c bus 982 to run and CFG_I2C_SLAVE to be the address of this node (ie 983 the cpu's i2c node address). 984 985 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 986 sets the cpu up as a master node and so its address should 987 therefore be cleared to 0 (See, eg, MPC823e User's Manual 988 p.16-473). So, set CFG_I2C_SLAVE to 0. 989 990 That's all that's required for CONFIG_HARD_I2C. 991 992 If you use the software i2c interface (CONFIG_SOFT_I2C) 993 then the following macros need to be defined (examples are 994 from include/configs/lwmon.h): 995 996 I2C_INIT 997 998 (Optional). Any commands necessary to enable the I2C 999 controller or configure ports. 1000 1001 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1002 1003 I2C_PORT 1004 1005 (Only for MPC8260 CPU). The I/O port to use (the code 1006 assumes both bits are on the same port). Valid values 1007 are 0..3 for ports A..D. 1008 1009 I2C_ACTIVE 1010 1011 The code necessary to make the I2C data line active 1012 (driven). If the data line is open collector, this 1013 define can be null. 1014 1015 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1016 1017 I2C_TRISTATE 1018 1019 The code necessary to make the I2C data line tri-stated 1020 (inactive). If the data line is open collector, this 1021 define can be null. 1022 1023 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1024 1025 I2C_READ 1026 1027 Code that returns TRUE if the I2C data line is high, 1028 FALSE if it is low. 1029 1030 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1031 1032 I2C_SDA(bit) 1033 1034 If <bit> is TRUE, sets the I2C data line high. If it 1035 is FALSE, it clears it (low). 1036 1037 eg: #define I2C_SDA(bit) \ 1038 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1039 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1040 1041 I2C_SCL(bit) 1042 1043 If <bit> is TRUE, sets the I2C clock line high. If it 1044 is FALSE, it clears it (low). 1045 1046 eg: #define I2C_SCL(bit) \ 1047 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1048 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1049 1050 I2C_DELAY 1051 1052 This delay is invoked four times per clock cycle so this 1053 controls the rate of data transfer. The data rate thus 1054 is 1 / (I2C_DELAY * 4). Often defined to be something 1055 like: 1056 1057 #define I2C_DELAY udelay(2) 1058 1059 CFG_I2C_INIT_BOARD 1060 1061 When a board is reset during an i2c bus transfer 1062 chips might think that the current transfer is still 1063 in progress. On some boards it is possible to access 1064 the i2c SCLK line directly, either by using the 1065 processor pin as a GPIO or by having a second pin 1066 connected to the bus. If this option is defined a 1067 custom i2c_init_board() routine in boards/xxx/board.c 1068 is run early in the boot sequence. 1069 1070- SPI Support: CONFIG_SPI 1071 1072 Enables SPI driver (so far only tested with 1073 SPI EEPROM, also an instance works with Crystal A/D and 1074 D/As on the SACSng board) 1075 1076 CONFIG_SPI_X 1077 1078 Enables extended (16-bit) SPI EEPROM addressing. 1079 (symmetrical to CONFIG_I2C_X) 1080 1081 CONFIG_SOFT_SPI 1082 1083 Enables a software (bit-bang) SPI driver rather than 1084 using hardware support. This is a general purpose 1085 driver that only requires three general I/O port pins 1086 (two outputs, one input) to function. If this is 1087 defined, the board configuration must define several 1088 SPI configuration items (port pins to use, etc). For 1089 an example, see include/configs/sacsng.h. 1090 1091- FPGA Support: CONFIG_FPGA_COUNT 1092 1093 Specify the number of FPGA devices to support. 1094 1095 CONFIG_FPGA 1096 1097 Used to specify the types of FPGA devices. For 1098 example, 1099 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1100 1101 CFG_FPGA_PROG_FEEDBACK 1102 1103 Enable printing of hash marks during FPGA 1104 configuration. 1105 1106 CFG_FPGA_CHECK_BUSY 1107 1108 Enable checks on FPGA configuration interface busy 1109 status by the configuration function. This option 1110 will require a board or device specific function to 1111 be written. 1112 1113 CONFIG_FPGA_DELAY 1114 1115 If defined, a function that provides delays in the 1116 FPGA configuration driver. 1117 1118 CFG_FPGA_CHECK_CTRLC 1119 1120 Allow Control-C to interrupt FPGA configuration 1121 1122 CFG_FPGA_CHECK_ERROR 1123 1124 Check for configuration errors during FPGA bitfile 1125 loading. For example, abort during Virtex II 1126 configuration if the INIT_B line goes low (which 1127 indicated a CRC error). 1128 1129 CFG_FPGA_WAIT_INIT 1130 1131 Maximum time to wait for the INIT_B line to deassert 1132 after PROB_B has been deasserted during a Virtex II 1133 FPGA configuration sequence. The default time is 500 mS. 1134 1135 CFG_FPGA_WAIT_BUSY 1136 1137 Maximum time to wait for BUSY to deassert during 1138 Virtex II FPGA configuration. The default is 5 mS. 1139 1140 CFG_FPGA_WAIT_CONFIG 1141 1142 Time to wait after FPGA configuration. The default is 1143 200 mS. 1144 1145- FPGA Support: CONFIG_FPGA_COUNT 1146 1147 Specify the number of FPGA devices to support. 1148 1149 CONFIG_FPGA 1150 1151 Used to specify the types of FPGA devices. For example, 1152 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 1153 1154 CFG_FPGA_PROG_FEEDBACK 1155 1156 Enable printing of hash marks during FPGA configuration. 1157 1158 CFG_FPGA_CHECK_BUSY 1159 1160 Enable checks on FPGA configuration interface busy 1161 status by the configuration function. This option 1162 will require a board or device specific function to 1163 be written. 1164 1165 CONFIG_FPGA_DELAY 1166 1167 If defined, a function that provides delays in the FPGA 1168 configuration driver. 1169 1170 CFG_FPGA_CHECK_CTRLC 1171 Allow Control-C to interrupt FPGA configuration 1172 1173 CFG_FPGA_CHECK_ERROR 1174 1175 Check for configuration errors during FPGA bitfile 1176 loading. For example, abort during Virtex II 1177 configuration if the INIT_B line goes low (which 1178 indicated a CRC error). 1179 1180 CFG_FPGA_WAIT_INIT 1181 1182 Maximum time to wait for the INIT_B line to deassert 1183 after PROB_B has been deasserted during a Virtex II 1184 FPGA configuration sequence. The default time is 500 1185 mS. 1186 1187 CFG_FPGA_WAIT_BUSY 1188 1189 Maximum time to wait for BUSY to deassert during 1190 Virtex II FPGA configuration. The default is 5 mS. 1191 1192 CFG_FPGA_WAIT_CONFIG 1193 1194 Time to wait after FPGA configuration. The default is 1195 200 mS. 1196 1197- Configuration Management: 1198 CONFIG_IDENT_STRING 1199 1200 If defined, this string will be added to the U-Boot 1201 version information (U_BOOT_VERSION) 1202 1203- Vendor Parameter Protection: 1204 1205 U-Boot considers the values of the environment 1206 variables "serial#" (Board Serial Number) and 1207 "ethaddr" (Ethernet Address) to be parameters that 1208 are set once by the board vendor / manufacturer, and 1209 protects these variables from casual modification by 1210 the user. Once set, these variables are read-only, 1211 and write or delete attempts are rejected. You can 1212 change this behviour: 1213 1214 If CONFIG_ENV_OVERWRITE is #defined in your config 1215 file, the write protection for vendor parameters is 1216 completely disabled. Anybody can change or delete 1217 these parameters. 1218 1219 Alternatively, if you #define _both_ CONFIG_ETHADDR 1220 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1221 ethernet address is installed in the environment, 1222 which can be changed exactly ONCE by the user. [The 1223 serial# is unaffected by this, i. e. it remains 1224 read-only.] 1225 1226- Protected RAM: 1227 CONFIG_PRAM 1228 1229 Define this variable to enable the reservation of 1230 "protected RAM", i. e. RAM which is not overwritten 1231 by U-Boot. Define CONFIG_PRAM to hold the number of 1232 kB you want to reserve for pRAM. You can overwrite 1233 this default value by defining an environment 1234 variable "pram" to the number of kB you want to 1235 reserve. Note that the board info structure will 1236 still show the full amount of RAM. If pRAM is 1237 reserved, a new environment variable "mem" will 1238 automatically be defined to hold the amount of 1239 remaining RAM in a form that can be passed as boot 1240 argument to Linux, for instance like that: 1241 1242 setenv bootargs ... mem=\$(mem) 1243 saveenv 1244 1245 This way you can tell Linux not to use this memory, 1246 either, which results in a memory region that will 1247 not be affected by reboots. 1248 1249 *WARNING* If your board configuration uses automatic 1250 detection of the RAM size, you must make sure that 1251 this memory test is non-destructive. So far, the 1252 following board configurations are known to be 1253 "pRAM-clean": 1254 1255 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1256 HERMES, IP860, RPXlite, LWMON, LANTEC, 1257 PCU_E, FLAGADM, TQM8260 1258 1259- Error Recovery: 1260 CONFIG_PANIC_HANG 1261 1262 Define this variable to stop the system in case of a 1263 fatal error, so that you have to reset it manually. 1264 This is probably NOT a good idea for an embedded 1265 system where you want to system to reboot 1266 automatically as fast as possible, but it may be 1267 useful during development since you can try to debug 1268 the conditions that lead to the situation. 1269 1270 CONFIG_NET_RETRY_COUNT 1271 1272 This variable defines the number of retries for 1273 network operations like ARP, RARP, TFTP, or BOOTP 1274 before giving up the operation. If not defined, a 1275 default value of 5 is used. 1276 1277- Command Interpreter: 1278 CFG_HUSH_PARSER 1279 1280 Define this variable to enable the "hush" shell (from 1281 Busybox) as command line interpreter, thus enabling 1282 powerful command line syntax like 1283 if...then...else...fi conditionals or `&&' and '||' 1284 constructs ("shell scripts"). 1285 1286 If undefined, you get the old, much simpler behaviour 1287 with a somewhat smaller memory footprint. 1288 1289 1290 CFG_PROMPT_HUSH_PS2 1291 1292 This defines the secondary prompt string, which is 1293 printed when the command interpreter needs more input 1294 to complete a command. Usually "> ". 1295 1296 Note: 1297 1298 In the current implementation, the local variables 1299 space and global environment variables space are 1300 separated. Local variables are those you define by 1301 simply typing `name=value'. To access a local 1302 variable later on, you have write `$name' or 1303 `${name}'; to execute the contents of a variable 1304 directly type `$name' at the command prompt. 1305 1306 Global environment variables are those you use 1307 setenv/printenv to work with. To run a command stored 1308 in such a variable, you need to use the run command, 1309 and you must not use the '$' sign to access them. 1310 1311 To store commands and special characters in a 1312 variable, please use double quotation marks 1313 surrounding the whole text of the variable, instead 1314 of the backslashes before semicolons and special 1315 symbols. 1316 1317- Default Environment 1318 CONFIG_EXTRA_ENV_SETTINGS 1319 1320 Define this to contain any number of null terminated 1321 strings (variable = value pairs) that will be part of 1322 the default environment compiled into the boot image. 1323 1324 For example, place something like this in your 1325 board's config file: 1326 1327 #define CONFIG_EXTRA_ENV_SETTINGS \ 1328 "myvar1=value1\0" \ 1329 "myvar2=value2\0" 1330 1331 Warning: This method is based on knowledge about the 1332 internal format how the environment is stored by the 1333 U-Boot code. This is NOT an official, exported 1334 interface! Although it is unlikely that this format 1335 will change soon, there is no guarantee either. 1336 You better know what you are doing here. 1337 1338 Note: overly (ab)use of the default environment is 1339 discouraged. Make sure to check other ways to preset 1340 the environment like the autoscript function or the 1341 boot command first. 1342 1343- DataFlash Support 1344 CONFIG_HAS_DATAFLASH 1345 1346 Defining this option enables DataFlash features and 1347 allows to read/write in Dataflash via the standard 1348 commands cp, md... 1349 1350- Show boot progress 1351 CONFIG_SHOW_BOOT_PROGRESS 1352 1353 Defining this option allows to add some board- 1354 specific code (calling a user-provided function 1355 "show_boot_progress(int)") that enables you to show 1356 the system's boot progress on some display (for 1357 example, some LED's) on your board. At the moment, 1358 the following checkpoints are implemented: 1359 1360 Arg Where When 1361 1 common/cmd_bootm.c before attempting to boot an image 1362 -1 common/cmd_bootm.c Image header has bad magic number 1363 2 common/cmd_bootm.c Image header has correct magic number 1364 -2 common/cmd_bootm.c Image header has bad checksum 1365 3 common/cmd_bootm.c Image header has correct checksum 1366 -3 common/cmd_bootm.c Image data has bad checksum 1367 4 common/cmd_bootm.c Image data has correct checksum 1368 -4 common/cmd_bootm.c Image is for unsupported architecture 1369 5 common/cmd_bootm.c Architecture check OK 1370 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1371 6 common/cmd_bootm.c Image Type check OK 1372 -6 common/cmd_bootm.c gunzip uncompression error 1373 -7 common/cmd_bootm.c Unimplemented compression type 1374 7 common/cmd_bootm.c Uncompression OK 1375 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1376 8 common/cmd_bootm.c Image Type check OK 1377 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1378 9 common/cmd_bootm.c Start initial ramdisk verification 1379 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1380 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1381 10 common/cmd_bootm.c Ramdisk header is OK 1382 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1383 11 common/cmd_bootm.c Ramdisk data has correct checksum 1384 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1385 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1386 13 common/cmd_bootm.c Start multifile image verification 1387 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1388 15 common/cmd_bootm.c All preparation done, transferring control to OS 1389 1390 -1 common/cmd_doc.c Bad usage of "doc" command 1391 -1 common/cmd_doc.c No boot device 1392 -1 common/cmd_doc.c Unknown Chip ID on boot device 1393 -1 common/cmd_doc.c Read Error on boot device 1394 -1 common/cmd_doc.c Image header has bad magic number 1395 1396 -1 common/cmd_ide.c Bad usage of "ide" command 1397 -1 common/cmd_ide.c No boot device 1398 -1 common/cmd_ide.c Unknown boot device 1399 -1 common/cmd_ide.c Unknown partition table 1400 -1 common/cmd_ide.c Invalid partition type 1401 -1 common/cmd_ide.c Read Error on boot device 1402 -1 common/cmd_ide.c Image header has bad magic number 1403 1404 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1405 1406 1407Modem Support: 1408-------------- 1409 1410[so far only for SMDK2400 and TRAB boards] 1411 1412- Modem support endable: 1413 CONFIG_MODEM_SUPPORT 1414 1415- RTS/CTS Flow control enable: 1416 CONFIG_HWFLOW 1417 1418- Modem debug support: 1419 CONFIG_MODEM_SUPPORT_DEBUG 1420 1421 Enables debugging stuff (char screen[1024], dbg()) 1422 for modem support. Useful only with BDI2000. 1423 1424- General: 1425 1426 In the target system modem support is enabled when a 1427 specific key (key combination) is pressed during 1428 power-on. Otherwise U-Boot will boot normally 1429 (autoboot). The key_pressed() fuction is called from 1430 board_init(). Currently key_pressed() is a dummy 1431 function, returning 1 and thus enabling modem 1432 initialization. 1433 1434 If there are no modem init strings in the 1435 environment, U-Boot proceed to autoboot; the 1436 previous output (banner, info printfs) will be 1437 supressed, though. 1438 1439 See also: doc/README.Modem 1440 1441 1442Configuration Settings: 1443----------------------- 1444 1445- CFG_LONGHELP: Defined when you want long help messages included; 1446 undefine this when you're short of memory. 1447 1448- CFG_PROMPT: This is what U-Boot prints on the console to 1449 prompt for user input. 1450 1451- CFG_CBSIZE: Buffer size for input from the Console 1452 1453- CFG_PBSIZE: Buffer size for Console output 1454 1455- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1456 1457- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1458 the application (usually a Linux kernel) when it is 1459 booted 1460 1461- CFG_BAUDRATE_TABLE: 1462 List of legal baudrate settings for this board. 1463 1464- CFG_CONSOLE_INFO_QUIET 1465 Suppress display of console information at boot. 1466 1467- CFG_CONSOLE_IS_IN_ENV 1468 If the board specific function 1469 extern int overwrite_console (void); 1470 returns 1, the stdin, stderr and stdout are switched to the 1471 serial port, else the settings in the environment are used. 1472 1473- CFG_CONSOLE_OVERWRITE_ROUTINE 1474 Enable the call to overwrite_console(). 1475 1476- CFG_CONSOLE_ENV_OVERWRITE 1477 Enable overwrite of previous console environment settings. 1478 1479- CFG_MEMTEST_START, CFG_MEMTEST_END: 1480 Begin and End addresses of the area used by the 1481 simple memory test. 1482 1483- CFG_ALT_MEMTEST: 1484 Enable an alternate, more extensive memory test. 1485 1486- CFG_TFTP_LOADADDR: 1487 Default load address for network file downloads 1488 1489- CFG_LOADS_BAUD_CHANGE: 1490 Enable temporary baudrate change while serial download 1491 1492- CFG_SDRAM_BASE: 1493 Physical start address of SDRAM. _Must_ be 0 here. 1494 1495- CFG_MBIO_BASE: 1496 Physical start address of Motherboard I/O (if using a 1497 Cogent motherboard) 1498 1499- CFG_FLASH_BASE: 1500 Physical start address of Flash memory. 1501 1502- CFG_MONITOR_BASE: 1503 Physical start address of boot monitor code (set by 1504 make config files to be same as the text base address 1505 (TEXT_BASE) used when linking) - same as 1506 CFG_FLASH_BASE when booting from flash. 1507 1508- CFG_MONITOR_LEN: 1509 Size of memory reserved for monitor code, used to 1510 determine _at_compile_time_ (!) if the environment is 1511 embedded within the U-Boot image, or in a separate 1512 flash sector. 1513 1514- CFG_MALLOC_LEN: 1515 Size of DRAM reserved for malloc() use. 1516 1517- CFG_BOOTMAPSZ: 1518 Maximum size of memory mapped by the startup code of 1519 the Linux kernel; all data that must be processed by 1520 the Linux kernel (bd_info, boot arguments, eventually 1521 initrd image) must be put below this limit. 1522 1523- CFG_MAX_FLASH_BANKS: 1524 Max number of Flash memory banks 1525 1526- CFG_MAX_FLASH_SECT: 1527 Max number of sectors on a Flash chip 1528 1529- CFG_FLASH_ERASE_TOUT: 1530 Timeout for Flash erase operations (in ms) 1531 1532- CFG_FLASH_WRITE_TOUT: 1533 Timeout for Flash write operations (in ms) 1534 1535- CFG_FLASH_LOCK_TOUT 1536 Timeout for Flash set sector lock bit operation (in ms) 1537 1538- CFG_FLASH_UNLOCK_TOUT 1539 Timeout for Flash clear lock bits operation (in ms) 1540 1541- CFG_FLASH_PROTECTION 1542 If defined, hardware flash sectors protection is used 1543 instead of U-Boot software protection. 1544 1545- CFG_DIRECT_FLASH_TFTP: 1546 1547 Enable TFTP transfers directly to flash memory; 1548 without this option such a download has to be 1549 performed in two steps: (1) download to RAM, and (2) 1550 copy from RAM to flash. 1551 1552 The two-step approach is usually more reliable, since 1553 you can check if the download worked before you erase 1554 the flash, but in some situations (when sytem RAM is 1555 too limited to allow for a tempory copy of the 1556 downloaded image) this option may be very useful. 1557 1558- CFG_FLASH_CFI: 1559 Define if the flash driver uses extra elements in the 1560 common flash structure for storing flash geometry 1561 1562- CFG_RX_ETH_BUFFER: 1563 Defines the number of ethernet receive buffers. On some 1564 ethernet controllers it is recommended to set this value 1565 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1566 buffers can be full shortly after enabling the interface 1567 on high ethernet traffic. 1568 Defaults to 4 if not defined. 1569 1570The following definitions that deal with the placement and management 1571of environment data (variable area); in general, we support the 1572following configurations: 1573 1574- CFG_ENV_IS_IN_FLASH: 1575 1576 Define this if the environment is in flash memory. 1577 1578 a) The environment occupies one whole flash sector, which is 1579 "embedded" in the text segment with the U-Boot code. This 1580 happens usually with "bottom boot sector" or "top boot 1581 sector" type flash chips, which have several smaller 1582 sectors at the start or the end. For instance, such a 1583 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1584 such a case you would place the environment in one of the 1585 4 kB sectors - with U-Boot code before and after it. With 1586 "top boot sector" type flash chips, you would put the 1587 environment in one of the last sectors, leaving a gap 1588 between U-Boot and the environment. 1589 1590 - CFG_ENV_OFFSET: 1591 1592 Offset of environment data (variable area) to the 1593 beginning of flash memory; for instance, with bottom boot 1594 type flash chips the second sector can be used: the offset 1595 for this sector is given here. 1596 1597 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1598 1599 - CFG_ENV_ADDR: 1600 1601 This is just another way to specify the start address of 1602 the flash sector containing the environment (instead of 1603 CFG_ENV_OFFSET). 1604 1605 - CFG_ENV_SECT_SIZE: 1606 1607 Size of the sector containing the environment. 1608 1609 1610 b) Sometimes flash chips have few, equal sized, BIG sectors. 1611 In such a case you don't want to spend a whole sector for 1612 the environment. 1613 1614 - CFG_ENV_SIZE: 1615 1616 If you use this in combination with CFG_ENV_IS_IN_FLASH 1617 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1618 of this flash sector for the environment. This saves 1619 memory for the RAM copy of the environment. 1620 1621 It may also save flash memory if you decide to use this 1622 when your environment is "embedded" within U-Boot code, 1623 since then the remainder of the flash sector could be used 1624 for U-Boot code. It should be pointed out that this is 1625 STRONGLY DISCOURAGED from a robustness point of view: 1626 updating the environment in flash makes it always 1627 necessary to erase the WHOLE sector. If something goes 1628 wrong before the contents has been restored from a copy in 1629 RAM, your target system will be dead. 1630 1631 - CFG_ENV_ADDR_REDUND 1632 CFG_ENV_SIZE_REDUND 1633 1634 These settings describe a second storage area used to hold 1635 a redundand copy of the environment data, so that there is 1636 a valid backup copy in case there is a power failure during 1637 a "saveenv" operation. 1638 1639BE CAREFUL! Any changes to the flash layout, and some changes to the 1640source code will make it necessary to adapt <board>/u-boot.lds* 1641accordingly! 1642 1643 1644- CFG_ENV_IS_IN_NVRAM: 1645 1646 Define this if you have some non-volatile memory device 1647 (NVRAM, battery buffered SRAM) which you want to use for the 1648 environment. 1649 1650 - CFG_ENV_ADDR: 1651 - CFG_ENV_SIZE: 1652 1653 These two #defines are used to determin the memory area you 1654 want to use for environment. It is assumed that this memory 1655 can just be read and written to, without any special 1656 provision. 1657 1658BE CAREFUL! The first access to the environment happens quite early 1659in U-Boot initalization (when we try to get the setting of for the 1660console baudrate). You *MUST* have mappend your NVRAM area then, or 1661U-Boot will hang. 1662 1663Please note that even with NVRAM we still use a copy of the 1664environment in RAM: we could work on NVRAM directly, but we want to 1665keep settings there always unmodified except somebody uses "saveenv" 1666to save the current settings. 1667 1668 1669- CFG_ENV_IS_IN_EEPROM: 1670 1671 Use this if you have an EEPROM or similar serial access 1672 device and a driver for it. 1673 1674 - CFG_ENV_OFFSET: 1675 - CFG_ENV_SIZE: 1676 1677 These two #defines specify the offset and size of the 1678 environment area within the total memory of your EEPROM. 1679 1680 - CFG_I2C_EEPROM_ADDR: 1681 If defined, specified the chip address of the EEPROM device. 1682 The default address is zero. 1683 1684 - CFG_EEPROM_PAGE_WRITE_BITS: 1685 If defined, the number of bits used to address bytes in a 1686 single page in the EEPROM device. A 64 byte page, for example 1687 would require six bits. 1688 1689 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1690 If defined, the number of milliseconds to delay between 1691 page writes. The default is zero milliseconds. 1692 1693 - CFG_I2C_EEPROM_ADDR_LEN: 1694 The length in bytes of the EEPROM memory array address. Note 1695 that this is NOT the chip address length! 1696 1697 - CFG_EEPROM_SIZE: 1698 The size in bytes of the EEPROM device. 1699 1700 1701- CFG_SPI_INIT_OFFSET 1702 1703 Defines offset to the initial SPI buffer area in DPRAM. The 1704 area is used at an early stage (ROM part) if the environment 1705 is configured to reside in the SPI EEPROM: We need a 520 byte 1706 scratch DPRAM area. It is used between the two initialization 1707 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1708 to be a good choice since it makes it far enough from the 1709 start of the data area as well as from the stack pointer. 1710 1711Please note that the environment is read-only as long as the monitor 1712has been relocated to RAM and a RAM copy of the environment has been 1713created; also, when using EEPROM you will have to use getenv_r() 1714until then to read environment variables. 1715 1716The environment is protected by a CRC32 checksum. Before the monitor 1717is relocated into RAM, as a result of a bad CRC you will be working 1718with the compiled-in default environment - *silently*!!! [This is 1719necessary, because the first environment variable we need is the 1720"baudrate" setting for the console - if we have a bad CRC, we don't 1721have any device yet where we could complain.] 1722 1723Note: once the monitor has been relocated, then it will complain if 1724the default environment is used; a new CRC is computed as soon as you 1725use the "saveenv" command to store a valid environment. 1726 1727 1728Low Level (hardware related) configuration options: 1729--------------------------------------------------- 1730 1731- CFG_CACHELINE_SIZE: 1732 Cache Line Size of the CPU. 1733 1734- CFG_DEFAULT_IMMR: 1735 Default address of the IMMR after system reset. 1736 1737 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 1738 and RPXsuper) to be able to adjust the position of 1739 the IMMR register after a reset. 1740 1741- Floppy Disk Support: 1742 CFG_FDC_DRIVE_NUMBER 1743 1744 the default drive number (default value 0) 1745 1746 CFG_ISA_IO_STRIDE 1747 1748 defines the spacing between fdc chipset registers 1749 (default value 1) 1750 1751 CFG_ISA_IO_OFFSET 1752 1753 defines the offset of register from address. It 1754 depends on which part of the data bus is connected to 1755 the fdc chipset. (default value 0) 1756 1757 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 1758 CFG_FDC_DRIVE_NUMBER are undefined, they take their 1759 default value. 1760 1761 if CFG_FDC_HW_INIT is defined, then the function 1762 fdc_hw_init() is called at the beginning of the FDC 1763 setup. fdc_hw_init() must be provided by the board 1764 source code. It is used to make hardware dependant 1765 initializations. 1766 1767- CFG_IMMR: Physical address of the Internal Memory Mapped 1768 Register; DO NOT CHANGE! (11-4) 1769 [MPC8xx systems only] 1770 1771- CFG_INIT_RAM_ADDR: 1772 1773 Start address of memory area that can be used for 1774 initial data and stack; please note that this must be 1775 writable memory that is working WITHOUT special 1776 initialization, i. e. you CANNOT use normal RAM which 1777 will become available only after programming the 1778 memory controller and running certain initialization 1779 sequences. 1780 1781 U-Boot uses the following memory types: 1782 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1783 - MPC824X: data cache 1784 - PPC4xx: data cache 1785 1786- CFG_GBL_DATA_OFFSET: 1787 1788 Offset of the initial data structure in the memory 1789 area defined by CFG_INIT_RAM_ADDR. Usually 1790 CFG_GBL_DATA_OFFSET is chosen such that the initial 1791 data is located at the end of the available space 1792 (sometimes written as (CFG_INIT_RAM_END - 1793 CFG_INIT_DATA_SIZE), and the initial stack is just 1794 below that area (growing from (CFG_INIT_RAM_ADDR + 1795 CFG_GBL_DATA_OFFSET) downward. 1796 1797 Note: 1798 On the MPC824X (or other systems that use the data 1799 cache for initial memory) the address chosen for 1800 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1801 point to an otherwise UNUSED address space between 1802 the top of RAM and the start of the PCI space. 1803 1804- CFG_SIUMCR: SIU Module Configuration (11-6) 1805 1806- CFG_SYPCR: System Protection Control (11-9) 1807 1808- CFG_TBSCR: Time Base Status and Control (11-26) 1809 1810- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1811 1812- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1813 1814- CFG_SCCR: System Clock and reset Control Register (15-27) 1815 1816- CFG_OR_TIMING_SDRAM: 1817 SDRAM timing 1818 1819- CFG_MAMR_PTA: 1820 periodic timer for refresh 1821 1822- CFG_DER: Debug Event Register (37-47) 1823 1824- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1825 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1826 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1827 CFG_BR1_PRELIM: 1828 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1829 1830- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1831 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1832 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1833 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1834 1835- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1836 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1837 Machine Mode Register and Memory Periodic Timer 1838 Prescaler definitions (SDRAM timing) 1839 1840- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1841 enable I2C microcode relocation patch (MPC8xx); 1842 define relocation offset in DPRAM [DSP2] 1843 1844- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1845 enable SPI microcode relocation patch (MPC8xx); 1846 define relocation offset in DPRAM [SCC4] 1847 1848- CFG_USE_OSCCLK: 1849 Use OSCM clock mode on MBX8xx board. Be careful, 1850 wrong setting might damage your board. Read 1851 doc/README.MBX before setting this variable! 1852 1853- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 1854 Offset of the bootmode word in DPRAM used by post 1855 (Power On Self Tests). This definition overrides 1856 #define'd default value in commproc.h resp. 1857 cpm_8260.h. 1858 1859- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 1860 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 1861 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 1862 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 1863 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 1864 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 1865 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 1866 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 1867 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 1868 1869Building the Software: 1870====================== 1871 1872Building U-Boot has been tested in native PPC environments (on a 1873PowerBook G3 running LinuxPPC 2000) and in cross environments 1874(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1875NetBSD 1.5 on x86). 1876 1877If you are not using a native PPC environment, it is assumed that you 1878have the GNU cross compiling tools available in your path and named 1879with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1880you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1881the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1882change it to: 1883 1884 CROSS_COMPILE = ppc_4xx- 1885 1886 1887U-Boot is intended to be simple to build. After installing the 1888sources you must configure U-Boot for one specific board type. This 1889is done by typing: 1890 1891 make NAME_config 1892 1893where "NAME_config" is the name of one of the existing 1894configurations; the following names are supported: 1895 1896 ADCIOP_config GTH_config TQM850L_config 1897 ADS860_config IP860_config TQM855L_config 1898 AR405_config IVML24_config TQM860L_config 1899 CANBT_config IVMS8_config WALNUT405_config 1900 CPCI405_config LANTEC_config cogent_common_config 1901 CPCIISER4_config MBX_config cogent_mpc8260_config 1902 CU824_config MBX860T_config cogent_mpc8xx_config 1903 ESTEEM192E_config RPXlite_config hermes_config 1904 ETX094_config RPXsuper_config hymod_config 1905 FADS823_config SM850_config lwmon_config 1906 FADS850SAR_config SPD823TS_config pcu_e_config 1907 FADS860T_config SXNI855T_config rsdproto_config 1908 FPS850L_config Sandpoint8240_config sbc8260_config 1909 GENIETV_config TQM823L_config PIP405_config 1910 GEN860T_config EBONY_config FPS860L_config 1911 ELPT860_config cmi_mpc5xx_config NETVIA_config 1912 at91rm9200dk_config omap1510inn_config MPC8260ADS_config 1913 omap1610inn_config 1914Note: for some board special configuration names may exist; check if 1915 additional information is available from the board vendor; for 1916 instance, the TQM8xxL systems run normally at 50 MHz and use a 1917 SCC for 10baseT ethernet; there are also systems with 80 MHz 1918 CPU clock, and an optional Fast Ethernet module is available 1919 for CPU's with FEC. You can select such additional "features" 1920 when chosing the configuration, i. e. 1921 1922 make TQM860L_config 1923 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1924 1925 make TQM860L_FEC_config 1926 - will configure for a TQM860L at 50MHz with FEC for ethernet 1927 1928 make TQM860L_80MHz_config 1929 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1930 interface 1931 1932 make TQM860L_FEC_80MHz_config 1933 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1934 1935 make TQM823L_LCD_config 1936 - will configure for a TQM823L with U-Boot console on LCD 1937 1938 make TQM823L_LCD_80MHz_config 1939 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1940 1941 etc. 1942 1943 1944Finally, type "make all", and you should get some working U-Boot 1945images ready for download to / installation on your system: 1946 1947- "u-boot.bin" is a raw binary image 1948- "u-boot" is an image in ELF binary format 1949- "u-boot.srec" is in Motorola S-Record format 1950 1951 1952Please be aware that the Makefiles assume you are using GNU make, so 1953for instance on NetBSD you might need to use "gmake" instead of 1954native "make". 1955 1956 1957If the system board that you have is not listed, then you will need 1958to port U-Boot to your hardware platform. To do this, follow these 1959steps: 1960 19611. Add a new configuration option for your board to the toplevel 1962 "Makefile" and to the "MAKEALL" script, using the existing 1963 entries as examples. Note that here and at many other places 1964 boards and other names are listed in alphabetical sort order. Please 1965 keep this order. 19662. Create a new directory to hold your board specific code. Add any 1967 files you need. In your board directory, you will need at least 1968 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 19693. Create a new configuration file "include/configs/<board>.h" for 1970 your board 19713. If you're porting U-Boot to a new CPU, then also create a new 1972 directory to hold your CPU specific code. Add any files you need. 19734. Run "make <board>_config" with your new name. 19745. Type "make", and you should get a working "u-boot.srec" file 1975 to be installed on your target system. 19766. Debug and solve any problems that might arise. 1977 [Of course, this last step is much harder than it sounds.] 1978 1979 1980Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1981============================================================== 1982 1983If you have modified U-Boot sources (for instance added a new board 1984or support for new devices, a new CPU, etc.) you are expected to 1985provide feedback to the other developers. The feedback normally takes 1986the form of a "patch", i. e. a context diff against a certain (latest 1987official or latest in CVS) version of U-Boot sources. 1988 1989But before you submit such a patch, please verify that your modifi- 1990cation did not break existing code. At least make sure that *ALL* of 1991the supported boards compile WITHOUT ANY compiler warnings. To do so, 1992just run the "MAKEALL" script, which will configure and build U-Boot 1993for ALL supported system. Be warned, this will take a while. You can 1994select which (cross) compiler to use by passing a `CROSS_COMPILE' 1995environment variable to the script, i. e. to use the cross tools from 1996MontaVista's Hard Hat Linux you can type 1997 1998 CROSS_COMPILE=ppc_8xx- MAKEALL 1999 2000or to build on a native PowerPC system you can type 2001 2002 CROSS_COMPILE=' ' MAKEALL 2003 2004See also "U-Boot Porting Guide" below. 2005 2006 2007Monitor Commands - Overview: 2008============================ 2009 2010go - start application at address 'addr' 2011run - run commands in an environment variable 2012bootm - boot application image from memory 2013bootp - boot image via network using BootP/TFTP protocol 2014tftpboot- boot image via network using TFTP protocol 2015 and env variables "ipaddr" and "serverip" 2016 (and eventually "gatewayip") 2017rarpboot- boot image via network using RARP/TFTP protocol 2018diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2019loads - load S-Record file over serial line 2020loadb - load binary file over serial line (kermit mode) 2021md - memory display 2022mm - memory modify (auto-incrementing) 2023nm - memory modify (constant address) 2024mw - memory write (fill) 2025cp - memory copy 2026cmp - memory compare 2027crc32 - checksum calculation 2028imd - i2c memory display 2029imm - i2c memory modify (auto-incrementing) 2030inm - i2c memory modify (constant address) 2031imw - i2c memory write (fill) 2032icrc32 - i2c checksum calculation 2033iprobe - probe to discover valid I2C chip addresses 2034iloop - infinite loop on address range 2035isdram - print SDRAM configuration information 2036sspi - SPI utility commands 2037base - print or set address offset 2038printenv- print environment variables 2039setenv - set environment variables 2040saveenv - save environment variables to persistent storage 2041protect - enable or disable FLASH write protection 2042erase - erase FLASH memory 2043flinfo - print FLASH memory information 2044bdinfo - print Board Info structure 2045iminfo - print header information for application image 2046coninfo - print console devices and informations 2047ide - IDE sub-system 2048loop - infinite loop on address range 2049mtest - simple RAM test 2050icache - enable or disable instruction cache 2051dcache - enable or disable data cache 2052reset - Perform RESET of the CPU 2053echo - echo args to console 2054version - print monitor version 2055help - print online help 2056? - alias for 'help' 2057 2058 2059Monitor Commands - Detailed Description: 2060======================================== 2061 2062TODO. 2063 2064For now: just type "help <command>". 2065 2066 2067Environment Variables: 2068====================== 2069 2070U-Boot supports user configuration using Environment Variables which 2071can be made persistent by saving to Flash memory. 2072 2073Environment Variables are set using "setenv", printed using 2074"printenv", and saved to Flash using "saveenv". Using "setenv" 2075without a value can be used to delete a variable from the 2076environment. As long as you don't save the environment you are 2077working with an in-memory copy. In case the Flash area containing the 2078environment is erased by accident, a default environment is provided. 2079 2080Some configuration options can be set using Environment Variables: 2081 2082 baudrate - see CONFIG_BAUDRATE 2083 2084 bootdelay - see CONFIG_BOOTDELAY 2085 2086 bootcmd - see CONFIG_BOOTCOMMAND 2087 2088 bootargs - Boot arguments when booting an RTOS image 2089 2090 bootfile - Name of the image to load with TFTP 2091 2092 autoload - if set to "no" (any string beginning with 'n'), 2093 "bootp" will just load perform a lookup of the 2094 configuration from the BOOTP server, but not try to 2095 load any image using TFTP 2096 2097 autostart - if set to "yes", an image loaded using the "bootp", 2098 "rarpboot", "tftpboot" or "diskboot" commands will 2099 be automatically started (by internally calling 2100 "bootm") 2101 2102 If set to "no", a standalone image passed to the 2103 "bootm" command will be copied to the load address 2104 (and eventually uncompressed), but NOT be started. 2105 This can be used to load and uncompress arbitrary 2106 data. 2107 2108 initrd_high - restrict positioning of initrd images: 2109 If this variable is not set, initrd images will be 2110 copied to the highest possible address in RAM; this 2111 is usually what you want since it allows for 2112 maximum initrd size. If for some reason you want to 2113 make sure that the initrd image is loaded below the 2114 CFG_BOOTMAPSZ limit, you can set this environment 2115 variable to a value of "no" or "off" or "0". 2116 Alternatively, you can set it to a maximum upper 2117 address to use (U-Boot will still check that it 2118 does not overwrite the U-Boot stack and data). 2119 2120 For instance, when you have a system with 16 MB 2121 RAM, and want to reserve 4 MB from use by Linux, 2122 you can do this by adding "mem=12M" to the value of 2123 the "bootargs" variable. However, now you must make 2124 sure that the initrd image is placed in the first 2125 12 MB as well - this can be done with 2126 2127 setenv initrd_high 00c00000 2128 2129 If you set initrd_high to 0xFFFFFFFF, this is an 2130 indication to U-Boot that all addresses are legal 2131 for the Linux kernel, including addresses in flash 2132 memory. In this case U-Boot will NOT COPY the 2133 ramdisk at all. This may be useful to reduce the 2134 boot time on your system, but requires that this 2135 feature is supported by your Linux kernel. 2136 2137 ipaddr - IP address; needed for tftpboot command 2138 2139 loadaddr - Default load address for commands like "bootp", 2140 "rarpboot", "tftpboot", "loadb" or "diskboot" 2141 2142 loads_echo - see CONFIG_LOADS_ECHO 2143 2144 serverip - TFTP server IP address; needed for tftpboot command 2145 2146 bootretry - see CONFIG_BOOT_RETRY_TIME 2147 2148 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2149 2150 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2151 2152 2153The following environment variables may be used and automatically 2154updated by the network boot commands ("bootp" and "rarpboot"), 2155depending the information provided by your boot server: 2156 2157 bootfile - see above 2158 dnsip - IP address of your Domain Name Server 2159 dnsip2 - IP address of your secondary Domain Name Server 2160 gatewayip - IP address of the Gateway (Router) to use 2161 hostname - Target hostname 2162 ipaddr - see above 2163 netmask - Subnet Mask 2164 rootpath - Pathname of the root filesystem on the NFS server 2165 serverip - see above 2166 2167 2168There are two special Environment Variables: 2169 2170 serial# - contains hardware identification information such 2171 as type string and/or serial number 2172 ethaddr - Ethernet address 2173 2174These variables can be set only once (usually during manufacturing of 2175the board). U-Boot refuses to delete or overwrite these variables 2176once they have been set once. 2177 2178 2179Further special Environment Variables: 2180 2181 ver - Contains the U-Boot version string as printed 2182 with the "version" command. This variable is 2183 readonly (see CONFIG_VERSION_VARIABLE). 2184 2185 2186Please note that changes to some configuration parameters may take 2187only effect after the next boot (yes, that's just like Windoze :-). 2188 2189 2190Command Line Parsing: 2191===================== 2192 2193There are two different command line parsers available with U-Boot: 2194the old "simple" one, and the much more powerful "hush" shell: 2195 2196Old, simple command line parser: 2197-------------------------------- 2198 2199- supports environment variables (through setenv / saveenv commands) 2200- several commands on one line, separated by ';' 2201- variable substitution using "... $(name) ..." syntax 2202- special characters ('$', ';') can be escaped by prefixing with '\', 2203 for example: 2204 setenv bootcmd bootm \$(address) 2205- You can also escape text by enclosing in single apostrophes, for example: 2206 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2207 2208Hush shell: 2209----------- 2210 2211- similar to Bourne shell, with control structures like 2212 if...then...else...fi, for...do...done; while...do...done, 2213 until...do...done, ... 2214- supports environment ("global") variables (through setenv / saveenv 2215 commands) and local shell variables (through standard shell syntax 2216 "name=value"); only environment variables can be used with "run" 2217 command 2218 2219General rules: 2220-------------- 2221 2222(1) If a command line (or an environment variable executed by a "run" 2223 command) contains several commands separated by semicolon, and 2224 one of these commands fails, then the remaining commands will be 2225 executed anyway. 2226 2227(2) If you execute several variables with one call to run (i. e. 2228 calling run with a list af variables as arguments), any failing 2229 command will cause "run" to terminate, i. e. the remaining 2230 variables are not executed. 2231 2232Note for Redundant Ethernet Interfaces: 2233======================================= 2234 2235Some boards come with redundant ethernet interfaces; U-Boot supports 2236such configurations and is capable of automatic selection of a 2237"working" interface when needed. MAC assignment works as follows: 2238 2239Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2240MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2241"eth1addr" (=>eth1), "eth2addr", ... 2242 2243If the network interface stores some valid MAC address (for instance 2244in SROM), this is used as default address if there is NO correspon- 2245ding setting in the environment; if the corresponding environment 2246variable is set, this overrides the settings in the card; that means: 2247 2248o If the SROM has a valid MAC address, and there is no address in the 2249 environment, the SROM's address is used. 2250 2251o If there is no valid address in the SROM, and a definition in the 2252 environment exists, then the value from the environment variable is 2253 used. 2254 2255o If both the SROM and the environment contain a MAC address, and 2256 both addresses are the same, this MAC address is used. 2257 2258o If both the SROM and the environment contain a MAC address, and the 2259 addresses differ, the value from the environment is used and a 2260 warning is printed. 2261 2262o If neither SROM nor the environment contain a MAC address, an error 2263 is raised. 2264 2265 2266Image Formats: 2267============== 2268 2269The "boot" commands of this monitor operate on "image" files which 2270can be basicly anything, preceeded by a special header; see the 2271definitions in include/image.h for details; basicly, the header 2272defines the following image properties: 2273 2274* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2275 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2276 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2277 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2278* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2279 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2280 Currently supported: PowerPC). 2281* Compression Type (uncompressed, gzip, bzip2) 2282* Load Address 2283* Entry Point 2284* Image Name 2285* Image Timestamp 2286 2287The header is marked by a special Magic Number, and both the header 2288and the data portions of the image are secured against corruption by 2289CRC32 checksums. 2290 2291 2292Linux Support: 2293============== 2294 2295Although U-Boot should support any OS or standalone application 2296easily, the main focus has always been on Linux during the design of 2297U-Boot. 2298 2299U-Boot includes many features that so far have been part of some 2300special "boot loader" code within the Linux kernel. Also, any 2301"initrd" images to be used are no longer part of one big Linux image; 2302instead, kernel and "initrd" are separate images. This implementation 2303serves several purposes: 2304 2305- the same features can be used for other OS or standalone 2306 applications (for instance: using compressed images to reduce the 2307 Flash memory footprint) 2308 2309- it becomes much easier to port new Linux kernel versions because 2310 lots of low-level, hardware dependent stuff are done by U-Boot 2311 2312- the same Linux kernel image can now be used with different "initrd" 2313 images; of course this also means that different kernel images can 2314 be run with the same "initrd". This makes testing easier (you don't 2315 have to build a new "zImage.initrd" Linux image when you just 2316 change a file in your "initrd"). Also, a field-upgrade of the 2317 software is easier now. 2318 2319 2320Linux HOWTO: 2321============ 2322 2323Porting Linux to U-Boot based systems: 2324--------------------------------------- 2325 2326U-Boot cannot save you from doing all the necessary modifications to 2327configure the Linux device drivers for use with your target hardware 2328(no, we don't intend to provide a full virtual machine interface to 2329Linux :-). 2330 2331But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2332 2333Just make sure your machine specific header file (for instance 2334include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2335Information structure as we define in include/u-boot.h, and make 2336sure that your definition of IMAP_ADDR uses the same value as your 2337U-Boot configuration in CFG_IMMR. 2338 2339 2340Configuring the Linux kernel: 2341----------------------------- 2342 2343No specific requirements for U-Boot. Make sure you have some root 2344device (initial ramdisk, NFS) for your target system. 2345 2346 2347Building a Linux Image: 2348----------------------- 2349 2350With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2351not used. If you use recent kernel source, a new build target 2352"uImage" will exist which automatically builds an image usable by 2353U-Boot. Most older kernels also have support for a "pImage" target, 2354which was introduced for our predecessor project PPCBoot and uses a 2355100% compatible format. 2356 2357Example: 2358 2359 make TQM850L_config 2360 make oldconfig 2361 make dep 2362 make uImage 2363 2364The "uImage" build target uses a special tool (in 'tools/mkimage') to 2365encapsulate a compressed Linux kernel image with header information, 2366CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2367 2368* build a standard "vmlinux" kernel image (in ELF binary format): 2369 2370* convert the kernel into a raw binary image: 2371 2372 ${CROSS_COMPILE}-objcopy -O binary \ 2373 -R .note -R .comment \ 2374 -S vmlinux linux.bin 2375 2376* compress the binary image: 2377 2378 gzip -9 linux.bin 2379 2380* package compressed binary image for U-Boot: 2381 2382 mkimage -A ppc -O linux -T kernel -C gzip \ 2383 -a 0 -e 0 -n "Linux Kernel Image" \ 2384 -d linux.bin.gz uImage 2385 2386 2387The "mkimage" tool can also be used to create ramdisk images for use 2388with U-Boot, either separated from the Linux kernel image, or 2389combined into one file. "mkimage" encapsulates the images with a 64 2390byte header containing information about target architecture, 2391operating system, image type, compression method, entry points, time 2392stamp, CRC32 checksums, etc. 2393 2394"mkimage" can be called in two ways: to verify existing images and 2395print the header information, or to build new images. 2396 2397In the first form (with "-l" option) mkimage lists the information 2398contained in the header of an existing U-Boot image; this includes 2399checksum verification: 2400 2401 tools/mkimage -l image 2402 -l ==> list image header information 2403 2404The second form (with "-d" option) is used to build a U-Boot image 2405from a "data file" which is used as image payload: 2406 2407 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2408 -n name -d data_file image 2409 -A ==> set architecture to 'arch' 2410 -O ==> set operating system to 'os' 2411 -T ==> set image type to 'type' 2412 -C ==> set compression type 'comp' 2413 -a ==> set load address to 'addr' (hex) 2414 -e ==> set entry point to 'ep' (hex) 2415 -n ==> set image name to 'name' 2416 -d ==> use image data from 'datafile' 2417 2418Right now, all Linux kernels use the same load address (0x00000000), 2419but the entry point address depends on the kernel version: 2420 2421- 2.2.x kernels have the entry point at 0x0000000C, 2422- 2.3.x and later kernels have the entry point at 0x00000000. 2423 2424So a typical call to build a U-Boot image would read: 2425 2426 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2427 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2428 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2429 > examples/uImage.TQM850L 2430 Image Name: 2.4.4 kernel for TQM850L 2431 Created: Wed Jul 19 02:34:59 2000 2432 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2433 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2434 Load Address: 0x00000000 2435 Entry Point: 0x00000000 2436 2437To verify the contents of the image (or check for corruption): 2438 2439 -> tools/mkimage -l examples/uImage.TQM850L 2440 Image Name: 2.4.4 kernel for TQM850L 2441 Created: Wed Jul 19 02:34:59 2000 2442 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2443 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2444 Load Address: 0x00000000 2445 Entry Point: 0x00000000 2446 2447NOTE: for embedded systems where boot time is critical you can trade 2448speed for memory and install an UNCOMPRESSED image instead: this 2449needs more space in Flash, but boots much faster since it does not 2450need to be uncompressed: 2451 2452 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 2453 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2454 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 2455 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 2456 > examples/uImage.TQM850L-uncompressed 2457 Image Name: 2.4.4 kernel for TQM850L 2458 Created: Wed Jul 19 02:34:59 2000 2459 Image Type: PowerPC Linux Kernel Image (uncompressed) 2460 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2461 Load Address: 0x00000000 2462 Entry Point: 0x00000000 2463 2464 2465Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2466when your kernel is intended to use an initial ramdisk: 2467 2468 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2469 > -A ppc -O linux -T ramdisk -C gzip \ 2470 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2471 Image Name: Simple Ramdisk Image 2472 Created: Wed Jan 12 14:01:50 2000 2473 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2474 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2475 Load Address: 0x00000000 2476 Entry Point: 0x00000000 2477 2478 2479Installing a Linux Image: 2480------------------------- 2481 2482To downloading a U-Boot image over the serial (console) interface, 2483you must convert the image to S-Record format: 2484 2485 objcopy -I binary -O srec examples/image examples/image.srec 2486 2487The 'objcopy' does not understand the information in the U-Boot 2488image header, so the resulting S-Record file will be relative to 2489address 0x00000000. To load it to a given address, you need to 2490specify the target address as 'offset' parameter with the 'loads' 2491command. 2492 2493Example: install the image to address 0x40100000 (which on the 2494TQM8xxL is in the first Flash bank): 2495 2496 => erase 40100000 401FFFFF 2497 2498 .......... done 2499 Erased 8 sectors 2500 2501 => loads 40100000 2502 ## Ready for S-Record download ... 2503 ~>examples/image.srec 2504 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2505 ... 2506 15989 15990 15991 15992 2507 [file transfer complete] 2508 [connected] 2509 ## Start Addr = 0x00000000 2510 2511 2512You can check the success of the download using the 'iminfo' command; 2513this includes a checksum verification so you can be sure no data 2514corruption happened: 2515 2516 => imi 40100000 2517 2518 ## Checking Image at 40100000 ... 2519 Image Name: 2.2.13 for initrd on TQM850L 2520 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2521 Data Size: 335725 Bytes = 327 kB = 0 MB 2522 Load Address: 00000000 2523 Entry Point: 0000000c 2524 Verifying Checksum ... OK 2525 2526 2527Boot Linux: 2528----------- 2529 2530The "bootm" command is used to boot an application that is stored in 2531memory (RAM or Flash). In case of a Linux kernel image, the contents 2532of the "bootargs" environment variable is passed to the kernel as 2533parameters. You can check and modify this variable using the 2534"printenv" and "setenv" commands: 2535 2536 2537 => printenv bootargs 2538 bootargs=root=/dev/ram 2539 2540 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2541 2542 => printenv bootargs 2543 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2544 2545 => bootm 40020000 2546 ## Booting Linux kernel at 40020000 ... 2547 Image Name: 2.2.13 for NFS on TQM850L 2548 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2549 Data Size: 381681 Bytes = 372 kB = 0 MB 2550 Load Address: 00000000 2551 Entry Point: 0000000c 2552 Verifying Checksum ... OK 2553 Uncompressing Kernel Image ... OK 2554 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 2555 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2556 time_init: decrementer frequency = 187500000/60 2557 Calibrating delay loop... 49.77 BogoMIPS 2558 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2559 ... 2560 2561If you want to boot a Linux kernel with initial ram disk, you pass 2562the memory addresses of both the kernel and the initrd image (PPBCOOT 2563format!) to the "bootm" command: 2564 2565 => imi 40100000 40200000 2566 2567 ## Checking Image at 40100000 ... 2568 Image Name: 2.2.13 for initrd on TQM850L 2569 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2570 Data Size: 335725 Bytes = 327 kB = 0 MB 2571 Load Address: 00000000 2572 Entry Point: 0000000c 2573 Verifying Checksum ... OK 2574 2575 ## Checking Image at 40200000 ... 2576 Image Name: Simple Ramdisk Image 2577 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2578 Data Size: 566530 Bytes = 553 kB = 0 MB 2579 Load Address: 00000000 2580 Entry Point: 00000000 2581 Verifying Checksum ... OK 2582 2583 => bootm 40100000 40200000 2584 ## Booting Linux kernel at 40100000 ... 2585 Image Name: 2.2.13 for initrd on TQM850L 2586 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2587 Data Size: 335725 Bytes = 327 kB = 0 MB 2588 Load Address: 00000000 2589 Entry Point: 0000000c 2590 Verifying Checksum ... OK 2591 Uncompressing Kernel Image ... OK 2592 ## Loading RAMDisk Image at 40200000 ... 2593 Image Name: Simple Ramdisk Image 2594 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2595 Data Size: 566530 Bytes = 553 kB = 0 MB 2596 Load Address: 00000000 2597 Entry Point: 00000000 2598 Verifying Checksum ... OK 2599 Loading Ramdisk ... OK 2600 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 2601 Boot arguments: root=/dev/ram 2602 time_init: decrementer frequency = 187500000/60 2603 Calibrating delay loop... 49.77 BogoMIPS 2604 ... 2605 RAMDISK: Compressed image found at block 0 2606 VFS: Mounted root (ext2 filesystem). 2607 2608 bash# 2609 2610More About U-Boot Image Types: 2611------------------------------ 2612 2613U-Boot supports the following image types: 2614 2615 "Standalone Programs" are directly runnable in the environment 2616 provided by U-Boot; it is expected that (if they behave 2617 well) you can continue to work in U-Boot after return from 2618 the Standalone Program. 2619 "OS Kernel Images" are usually images of some Embedded OS which 2620 will take over control completely. Usually these programs 2621 will install their own set of exception handlers, device 2622 drivers, set up the MMU, etc. - this means, that you cannot 2623 expect to re-enter U-Boot except by resetting the CPU. 2624 "RAMDisk Images" are more or less just data blocks, and their 2625 parameters (address, size) are passed to an OS kernel that is 2626 being started. 2627 "Multi-File Images" contain several images, typically an OS 2628 (Linux) kernel image and one or more data images like 2629 RAMDisks. This construct is useful for instance when you want 2630 to boot over the network using BOOTP etc., where the boot 2631 server provides just a single image file, but you want to get 2632 for instance an OS kernel and a RAMDisk image. 2633 2634 "Multi-File Images" start with a list of image sizes, each 2635 image size (in bytes) specified by an "uint32_t" in network 2636 byte order. This list is terminated by an "(uint32_t)0". 2637 Immediately after the terminating 0 follow the images, one by 2638 one, all aligned on "uint32_t" boundaries (size rounded up to 2639 a multiple of 4 bytes). 2640 2641 "Firmware Images" are binary images containing firmware (like 2642 U-Boot or FPGA images) which usually will be programmed to 2643 flash memory. 2644 2645 "Script files" are command sequences that will be executed by 2646 U-Boot's command interpreter; this feature is especially 2647 useful when you configure U-Boot to use a real shell (hush) 2648 as command interpreter. 2649 2650 2651Standalone HOWTO: 2652================= 2653 2654One of the features of U-Boot is that you can dynamically load and 2655run "standalone" applications, which can use some resources of 2656U-Boot like console I/O functions or interrupt services. 2657 2658Two simple examples are included with the sources: 2659 2660"Hello World" Demo: 2661------------------- 2662 2663'examples/hello_world.c' contains a small "Hello World" Demo 2664application; it is automatically compiled when you build U-Boot. 2665It's configured to run at address 0x00040004, so you can play with it 2666like that: 2667 2668 => loads 2669 ## Ready for S-Record download ... 2670 ~>examples/hello_world.srec 2671 1 2 3 4 5 6 7 8 9 10 11 ... 2672 [file transfer complete] 2673 [connected] 2674 ## Start Addr = 0x00040004 2675 2676 => go 40004 Hello World! This is a test. 2677 ## Starting application at 0x00040004 ... 2678 Hello World 2679 argc = 7 2680 argv[0] = "40004" 2681 argv[1] = "Hello" 2682 argv[2] = "World!" 2683 argv[3] = "This" 2684 argv[4] = "is" 2685 argv[5] = "a" 2686 argv[6] = "test." 2687 argv[7] = "<NULL>" 2688 Hit any key to exit ... 2689 2690 ## Application terminated, rc = 0x0 2691 2692Another example, which demonstrates how to register a CPM interrupt 2693handler with the U-Boot code, can be found in 'examples/timer.c'. 2694Here, a CPM timer is set up to generate an interrupt every second. 2695The interrupt service routine is trivial, just printing a '.' 2696character, but this is just a demo program. The application can be 2697controlled by the following keys: 2698 2699 ? - print current values og the CPM Timer registers 2700 b - enable interrupts and start timer 2701 e - stop timer and disable interrupts 2702 q - quit application 2703 2704 => loads 2705 ## Ready for S-Record download ... 2706 ~>examples/timer.srec 2707 1 2 3 4 5 6 7 8 9 10 11 ... 2708 [file transfer complete] 2709 [connected] 2710 ## Start Addr = 0x00040004 2711 2712 => go 40004 2713 ## Starting application at 0x00040004 ... 2714 TIMERS=0xfff00980 2715 Using timer 1 2716 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2717 2718Hit 'b': 2719 [q, b, e, ?] Set interval 1000000 us 2720 Enabling timer 2721Hit '?': 2722 [q, b, e, ?] ........ 2723 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2724Hit '?': 2725 [q, b, e, ?] . 2726 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2727Hit '?': 2728 [q, b, e, ?] . 2729 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2730Hit '?': 2731 [q, b, e, ?] . 2732 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2733Hit 'e': 2734 [q, b, e, ?] ...Stopping timer 2735Hit 'q': 2736 [q, b, e, ?] ## Application terminated, rc = 0x0 2737 2738 2739Minicom warning: 2740================ 2741 2742Over time, many people have reported problems when trying to use the 2743"minicom" terminal emulation program for serial download. I (wd) 2744consider minicom to be broken, and recommend not to use it. Under 2745Unix, I recommend to use C-Kermit for general purpose use (and 2746especially for kermit binary protocol download ("loadb" command), and 2747use "cu" for S-Record download ("loads" command). 2748 2749Nevertheless, if you absolutely want to use it try adding this 2750configuration to your "File transfer protocols" section: 2751 2752 Name Program Name U/D FullScr IO-Red. Multi 2753 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 2754 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 2755 2756 2757NetBSD Notes: 2758============= 2759 2760Starting at version 0.9.2, U-Boot supports NetBSD both as host 2761(build U-Boot) and target system (boots NetBSD/mpc8xx). 2762 2763Building requires a cross environment; it is known to work on 2764NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2765need gmake since the Makefiles are not compatible with BSD make). 2766Note that the cross-powerpc package does not install include files; 2767attempting to build U-Boot will fail because <machine/ansi.h> is 2768missing. This file has to be installed and patched manually: 2769 2770 # cd /usr/pkg/cross/powerpc-netbsd/include 2771 # mkdir powerpc 2772 # ln -s powerpc machine 2773 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2774 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2775 2776Native builds *don't* work due to incompatibilities between native 2777and U-Boot include files. 2778 2779Booting assumes that (the first part of) the image booted is a 2780stage-2 loader which in turn loads and then invokes the kernel 2781proper. Loader sources will eventually appear in the NetBSD source 2782tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2783meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2784details. 2785 2786 2787Implementation Internals: 2788========================= 2789 2790The following is not intended to be a complete description of every 2791implementation detail. However, it should help to understand the 2792inner workings of U-Boot and make it easier to port it to custom 2793hardware. 2794 2795 2796Initial Stack, Global Data: 2797--------------------------- 2798 2799The implementation of U-Boot is complicated by the fact that U-Boot 2800starts running out of ROM (flash memory), usually without access to 2801system RAM (because the memory controller is not initialized yet). 2802This means that we don't have writable Data or BSS segments, and BSS 2803is not initialized as zero. To be able to get a C environment working 2804at all, we have to allocate at least a minimal stack. Implementation 2805options for this are defined and restricted by the CPU used: Some CPU 2806models provide on-chip memory (like the IMMR area on MPC8xx and 2807MPC826x processors), on others (parts of) the data cache can be 2808locked as (mis-) used as memory, etc. 2809 2810 Chris Hallinan posted a good summary of these issues to the 2811 u-boot-users mailing list: 2812 2813 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 2814 From: "Chris Hallinan" <clh@net1plus.com> 2815 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 2816 ... 2817 2818 Correct me if I'm wrong, folks, but the way I understand it 2819 is this: Using DCACHE as initial RAM for Stack, etc, does not 2820 require any physical RAM backing up the cache. The cleverness 2821 is that the cache is being used as a temporary supply of 2822 necessary storage before the SDRAM controller is setup. It's 2823 beyond the scope of this list to expain the details, but you 2824 can see how this works by studying the cache architecture and 2825 operation in the architecture and processor-specific manuals. 2826 2827 OCM is On Chip Memory, which I believe the 405GP has 4K. It 2828 is another option for the system designer to use as an 2829 initial stack/ram area prior to SDRAM being available. Either 2830 option should work for you. Using CS 4 should be fine if your 2831 board designers haven't used it for something that would 2832 cause you grief during the initial boot! It is frequently not 2833 used. 2834 2835 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 2836 with your processor/board/system design. The default value 2837 you will find in any recent u-boot distribution in 2838 Walnut405.h should work for you. I'd set it to a value larger 2839 than your SDRAM module. If you have a 64MB SDRAM module, set 2840 it above 400_0000. Just make sure your board has no resources 2841 that are supposed to respond to that address! That code in 2842 start.S has been around a while and should work as is when 2843 you get the config right. 2844 2845 -Chris Hallinan 2846 DS4.COM, Inc. 2847 2848It is essential to remember this, since it has some impact on the C 2849code for the initialization procedures: 2850 2851* Initialized global data (data segment) is read-only. Do not attempt 2852 to write it. 2853 2854* Do not use any unitialized global data (or implicitely initialized 2855 as zero data - BSS segment) at all - this is undefined, initiali- 2856 zation is performed later (when relocating to RAM). 2857 2858* Stack space is very limited. Avoid big data buffers or things like 2859 that. 2860 2861Having only the stack as writable memory limits means we cannot use 2862normal global data to share information beween the code. But it 2863turned out that the implementation of U-Boot can be greatly 2864simplified by making a global data structure (gd_t) available to all 2865functions. We could pass a pointer to this data as argument to _all_ 2866functions, but this would bloat the code. Instead we use a feature of 2867the GCC compiler (Global Register Variables) to share the data: we 2868place a pointer (gd) to the global data into a register which we 2869reserve for this purpose. 2870 2871When choosing a register for such a purpose we are restricted by the 2872relevant (E)ABI specifications for the current architecture, and by 2873GCC's implementation. 2874 2875For PowerPC, the following registers have specific use: 2876 R1: stack pointer 2877 R2: TOC pointer 2878 R3-R4: parameter passing and return values 2879 R5-R10: parameter passing 2880 R13: small data area pointer 2881 R30: GOT pointer 2882 R31: frame pointer 2883 2884 (U-Boot also uses R14 as internal GOT pointer.) 2885 2886 ==> U-Boot will use R29 to hold a pointer to the global data 2887 2888 Note: on PPC, we could use a static initializer (since the 2889 address of the global data structure is known at compile time), 2890 but it turned out that reserving a register results in somewhat 2891 smaller code - although the code savings are not that big (on 2892 average for all boards 752 bytes for the whole U-Boot image, 2893 624 text + 127 data). 2894 2895On ARM, the following registers are used: 2896 2897 R0: function argument word/integer result 2898 R1-R3: function argument word 2899 R9: GOT pointer 2900 R10: stack limit (used only if stack checking if enabled) 2901 R11: argument (frame) pointer 2902 R12: temporary workspace 2903 R13: stack pointer 2904 R14: link register 2905 R15: program counter 2906 2907 ==> U-Boot will use R8 to hold a pointer to the global data 2908 2909 2910Memory Management: 2911------------------ 2912 2913U-Boot runs in system state and uses physical addresses, i.e. the 2914MMU is not used either for address mapping nor for memory protection. 2915 2916The available memory is mapped to fixed addresses using the memory 2917controller. In this process, a contiguous block is formed for each 2918memory type (Flash, SDRAM, SRAM), even when it consists of several 2919physical memory banks. 2920 2921U-Boot is installed in the first 128 kB of the first Flash bank (on 2922TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2923booting and sizing and initializing DRAM, the code relocates itself 2924to the upper end of DRAM. Immediately below the U-Boot code some 2925memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2926configuration setting]. Below that, a structure with global Board 2927Info data is placed, followed by the stack (growing downward). 2928 2929Additionally, some exception handler code is copied to the low 8 kB 2930of DRAM (0x00000000 ... 0x00001FFF). 2931 2932So a typical memory configuration with 16 MB of DRAM could look like 2933this: 2934 2935 0x0000 0000 Exception Vector code 2936 : 2937 0x0000 1FFF 2938 0x0000 2000 Free for Application Use 2939 : 2940 : 2941 2942 : 2943 : 2944 0x00FB FF20 Monitor Stack (Growing downward) 2945 0x00FB FFAC Board Info Data and permanent copy of global data 2946 0x00FC 0000 Malloc Arena 2947 : 2948 0x00FD FFFF 2949 0x00FE 0000 RAM Copy of Monitor Code 2950 ... eventually: LCD or video framebuffer 2951 ... eventually: pRAM (Protected RAM - unchanged by reset) 2952 0x00FF FFFF [End of RAM] 2953 2954 2955System Initialization: 2956---------------------- 2957 2958In the reset configuration, U-Boot starts at the reset entry point 2959(on most PowerPC systens at address 0x00000100). Because of the reset 2960configuration for CS0# this is a mirror of the onboard Flash memory. 2961To be able to re-map memory U-Boot then jumps to its link address. 2962To be able to implement the initialization code in C, a (small!) 2963initial stack is set up in the internal Dual Ported RAM (in case CPUs 2964which provide such a feature like MPC8xx or MPC8260), or in a locked 2965part of the data cache. After that, U-Boot initializes the CPU core, 2966the caches and the SIU. 2967 2968Next, all (potentially) available memory banks are mapped using a 2969preliminary mapping. For example, we put them on 512 MB boundaries 2970(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2971on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2972programmed for SDRAM access. Using the temporary configuration, a 2973simple memory test is run that determines the size of the SDRAM 2974banks. 2975 2976When there is more than one SDRAM bank, and the banks are of 2977different size, the largest is mapped first. For equal size, the first 2978bank (CS2#) is mapped first. The first mapping is always for address 29790x00000000, with any additional banks following immediately to create 2980contiguous memory starting from 0. 2981 2982Then, the monitor installs itself at the upper end of the SDRAM area 2983and allocates memory for use by malloc() and for the global Board 2984Info data; also, the exception vector code is copied to the low RAM 2985pages, and the final stack is set up. 2986 2987Only after this relocation will you have a "normal" C environment; 2988until that you are restricted in several ways, mostly because you are 2989running from ROM, and because the code will have to be relocated to a 2990new address in RAM. 2991 2992 2993U-Boot Porting Guide: 2994---------------------- 2995 2996[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2997list, October 2002] 2998 2999 3000int main (int argc, char *argv[]) 3001{ 3002 sighandler_t no_more_time; 3003 3004 signal (SIGALRM, no_more_time); 3005 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3006 3007 if (available_money > available_manpower) { 3008 pay consultant to port U-Boot; 3009 return 0; 3010 } 3011 3012 Download latest U-Boot source; 3013 3014 Subscribe to u-boot-users mailing list; 3015 3016 if (clueless) { 3017 email ("Hi, I am new to U-Boot, how do I get started?"); 3018 } 3019 3020 while (learning) { 3021 Read the README file in the top level directory; 3022 Read http://www.denx.de/re/DPLG.html 3023 Read the source, Luke; 3024 } 3025 3026 if (available_money > toLocalCurrency ($2500)) { 3027 Buy a BDI2000; 3028 } else { 3029 Add a lot of aggravation and time; 3030 } 3031 3032 Create your own board support subdirectory; 3033 3034 Create your own board config file; 3035 3036 while (!running) { 3037 do { 3038 Add / modify source code; 3039 } until (compiles); 3040 Debug; 3041 if (clueless) 3042 email ("Hi, I am having problems..."); 3043 } 3044 Send patch file to Wolfgang; 3045 3046 return 0; 3047} 3048 3049void no_more_time (int sig) 3050{ 3051 hire_a_guru(); 3052} 3053 3054 3055Coding Standards: 3056----------------- 3057 3058All contributions to U-Boot should conform to the Linux kernel 3059coding style; see the file "Documentation/CodingStyle" in your Linux 3060kernel source directory. 3061 3062Please note that U-Boot is implemented in C (and to some small parts 3063in Assembler); no C++ is used, so please do not use C++ style 3064comments (//) in your code. 3065 3066Submissions which do not conform to the standards may be returned 3067with a request to reformat the changes. 3068 3069 3070Submitting Patches: 3071------------------- 3072 3073Since the number of patches for U-Boot is growing, we need to 3074establish some rules. Submissions which do not conform to these rules 3075may be rejected, even when they contain important and valuable stuff. 3076 3077 3078When you send a patch, please include the following information with 3079it: 3080 3081* For bug fixes: a description of the bug and how your patch fixes 3082 this bug. Please try to include a way of demonstrating that the 3083 patch actually fixes something. 3084 3085* For new features: a description of the feature and your 3086 implementation. 3087 3088* A CHANGELOG entry as plaintext (separate from the patch) 3089 3090* For major contributions, your entry to the CREDITS file 3091 3092* When you add support for a new board, don't forget to add this 3093 board to the MAKEALL script, too. 3094 3095* If your patch adds new configuration options, don't forget to 3096 document these in the README file. 3097 3098* The patch itself. If you are accessing the CVS repository use "cvs 3099 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3100 version of diff does not support these options, then get the latest 3101 version of GNU diff. 3102 3103 The current directory when running this command shall be the top 3104 level directory of the U-Boot source tree, or it's parent directory 3105 (i. e. please make sure that your patch includes sufficient 3106 directory information for the affected files). 3107 3108 We accept patches as plain text, MIME attachments or as uuencoded 3109 gzipped text. 3110 3111* If one logical set of modifications affects or creates several 3112 files, all these changes shall be submitted in a SINGLE patch file. 3113 3114* Changesets that contain different, unrelated modifications shall be 3115 submitted as SEPARATE patches, one patch per changeset. 3116 3117 3118Notes: 3119 3120* Before sending the patch, run the MAKEALL script on your patched 3121 source tree and make sure that no errors or warnings are reported 3122 for any of the boards. 3123 3124* Keep your modifications to the necessary minimum: A patch 3125 containing several unrelated changes or arbitrary reformats will be 3126 returned with a request to re-formatting / split it. 3127 3128* If you modify existing code, make sure that your new code does not 3129 add to the memory footprint of the code ;-) Small is beautiful! 3130 When adding new features, these should compile conditionally only 3131 (using #ifdef), and the resulting code with the new feature 3132 disabled must not need more memory than the old code without your 3133 modification. 3134