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 monitor for 28Embedded PowerPC boards, which can be installed in a boot ROM and 29used to test the hardware or download and run application code. 30 31The development of U-Boot is closely related to Linux: some parts of 32the source code originate in the Linux source tree, we still have 33some header files in common, and special provision has been made to 34support booting of Linux images. 35 36Some attention has been paid to make this software easily 37configurable and extendable. For instance, all monitor commands are 38implemented with the same call interface, so that it's very easy to 39add new commands. Also, instead of permanently adding rarely used 40code (for instance hardware test utilities) to the monitor, you can 41load and run it dynamically. 42 43 44Status: 45======= 46 47In general, all boards for which a configuration option exists in the 48Makefile have been tested to some extent and can be considered 49"working". In fact, many of them are used in production systems. 50 51In case of problems see the CHANGELOG and CREDITS files to find out 52who contributed the specific port. 53 54Exception from this rule: the port to the Sandpoint 8240 has not been 55completed yet. 56 57 58Where to get help: 59================== 60 61In case you have questions about, problems with or contributions for 62U-Boot you should send a message to the U-Boot mailing list at 63<u-boot-users@lists.sourceforge.net>. There is also an archive of 64previous traffic on the mailing list - please search the archive 65before asking FAQ's. Please see 66http://lists.sourceforge.net/lists/listinfo/u-boot-users/ 67 68 69Where we come from: 70=================== 71 72- start from 8xxrom sources 73- clean up code 74- make it easier to add custom boards 75- make it possible to add other [PowerPC] CPUs 76- extend functions, especially: 77 * Provide extended interface to Linux boot loader 78 * S-Record download 79 * network boot 80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot 81- add other CPU families (starting with ARM) 82 83 84Directory Hierarchy: 85==================== 86 87- board Board dependend files 88- common Misc architecture independend functions 89- cpu CPU specific files 90- disk Code for disk drive partition handling 91- doc Documentation (don't expect too much) 92- drivers Common used device drivers 93- dtt Digital Thermometer and Thermostat drivers 94- examples Example code for standalone applications, etc. 95- include Header Files 96- disk Harddisk interface code 97- net Networking code 98- ppc Files generic to PowerPC architecture 99- post Power On Self Test 100- post/arch Symlink to architecture specific Power On Self Test 101- post/arch-ppc PowerPC architecture specific Power On Self Test 102- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test 103- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test 104- rtc Real Time Clock drivers 105- tools Tools to build S-Record or U-Boot images, etc. 106 107- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs 108- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs 109- cpu/mpc824x Files specific to Motorola MPC824x CPUs 110- cpu/mpc8260 Files specific to Motorola MPC8260 CPU 111- cpu/ppc4xx Files specific to IBM 4xx CPUs 112 113- board/RPXClassic 114 Files specific to RPXClassic boards 115- board/RPXlite Files specific to RPXlite boards 116- board/c2mon Files specific to c2mon boards 117- board/cogent Files specific to Cogent boards 118 (need further configuration) 119 Files specific to CPCIISER4 boards 120- board/cpu86 Files specific to CPU86 boards 121- board/cray/ Files specific to boards manufactured by Cray 122- board/cray/L1 Files specific to L1 boards 123- board/cu824 Files specific to CU824 boards 124- board/ebony Files specific to IBM Ebony board 125- board/eric Files specific to ERIC boards 126- board/esd/ Files specific to boards manufactured by ESD 127- board/esd/adciop Files specific to ADCIOP boards 128- board/esd/ar405 Files specific to AR405 boards 129- board/esd/canbt Files specific to CANBT boards 130- board/esd/cpci405 Files specific to CPCI405 boards 131- board/esd/cpciiser4 Files specific to CPCIISER4 boards 132- board/esd/common Common files for ESD boards 133- board/esd/dasa_sim Files specific to DASA_SIM boards 134- board/esd/du405 Files specific to DU405 boards 135- board/esd/ocrtc Files specific to OCRTC boards 136- board/esd/pci405 Files specific to PCI405 boards 137- board/esteem192e 138 Files specific to ESTEEM192E boards 139- board/etx094 Files specific to ETX_094 boards 140- board/evb64260 141 Files specific to EVB64260 boards 142- board/fads Files specific to FADS boards 143- board/flagadm Files specific to FLAGADM boards 144- board/gen860t Files specific to GEN860T boards 145- board/genietv Files specific to GENIETV boards 146- board/gth Files specific to GTH boards 147- board/hermes Files specific to HERMES boards 148- board/hymod Files specific to HYMOD boards 149- board/icu862 Files specific to ICU862 boards 150- board/ip860 Files specific to IP860 boards 151- board/iphase4539 152 Files specific to Interphase4539 boards 153- board/ivm Files specific to IVMS8/IVML24 boards 154- board/lantec Files specific to LANTEC boards 155- board/lwmon Files specific to LWMON boards 156- board/mbx8xx Files specific to MBX boards 157- board/mpc8260ads 158 Files specific to MMPC8260ADS boards 159- board/mpl/ Files specific to boards manufactured by MPL 160- board/mpl/common Common files for MPL boards 161- board/mpl/pip405 Files specific to PIP405 boards 162- board/mpl/mip405 Files specific to MIP405 boards 163- board/musenki Files specific to MUSEKNI boards 164- board/mvs1 Files specific to MVS1 boards 165- board/nx823 Files specific to NX823 boards 166- board/oxc Files specific to OXC boards 167- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards 168- board/pm826 Files specific to PM826 boards 169- board/ppmc8260 170 Files specific to PPMC8260 boards 171- board/rpxsuper 172 Files specific to RPXsuper boards 173- board/rsdproto 174 Files specific to RSDproto boards 175- board/sandpoint 176 Files specific to Sandpoint boards 177- board/sbc8260 Files specific to SBC8260 boards 178- board/sacsng Files specific to SACSng boards 179- board/siemens Files specific to boards manufactured by Siemens AG 180- board/siemens/CCM Files specific to CCM boards 181- board/siemens/IAD210 Files specific to IAD210 boards 182- board/siemens/SCM Files specific to SCM boards 183- board/siemens/pcu_e Files specific to PCU_E boards 184- board/sixnet Files specific to SIXNET boards 185- board/spd8xx Files specific to SPD8xxTS boards 186- board/tqm8260 Files specific to TQM8260 boards 187- board/tqm8xx Files specific to TQM8xxL boards 188- board/w7o Files specific to W7O boards 189- board/walnut405 190 Files specific to Walnut405 boards 191- board/westel/ Files specific to boards manufactured by Westel Wireless 192- board/westel/amx860 Files specific to AMX860 boards 193- board/utx8245 Files specific to UTX8245 boards 194 195Software Configuration: 196======================= 197 198Configuration is usually done using C preprocessor defines; the 199rationale behind that is to avoid dead code whenever possible. 200 201There are two classes of configuration variables: 202 203* Configuration _OPTIONS_: 204 These are selectable by the user and have names beginning with 205 "CONFIG_". 206 207* Configuration _SETTINGS_: 208 These depend on the hardware etc. and should not be meddled with if 209 you don't know what you're doing; they have names beginning with 210 "CFG_". 211 212Later we will add a configuration tool - probably similar to or even 213identical to what's used for the Linux kernel. Right now, we have to 214do the configuration by hand, which means creating some symbolic 215links and editing some configuration files. We use the TQM8xxL boards 216as an example here. 217 218 219Selection of Processor Architecture and Board Type: 220--------------------------------------------------- 221 222For all supported boards there are ready-to-use default 223configurations available; just type "make <board_name>_config". 224 225Example: For a TQM823L module type: 226 227 cd u-boot 228 make TQM823L_config 229 230For the Cogent platform, you need to specify the cpu type as well; 231e.g. "make cogent_mpc8xx_config". And also configure the cogent 232directory according to the instructions in cogent/README. 233 234 235Configuration Options: 236---------------------- 237 238Configuration depends on the combination of board and CPU type; all 239such information is kept in a configuration file 240"include/configs/<board_name>.h". 241 242Example: For a TQM823L module, all configuration settings are in 243"include/configs/TQM823L.h". 244 245 246The following options need to be configured: 247 248- CPU Type: Define exactly one of 249 250 PowerPC based CPUs: 251 ------------------- 252 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 253 or CONFIG_MPC824X, CONFIG_MPC8260 254 or CONFIG_IOP480 255 or CONFIG_405GP 256 or CONFIG_440 257 or CONFIG_MPC74xx 258 259 ARM based CPUs: 260 --------------- 261 CONFIG_SA1110 262 CONFIG_ARM7 263 CONFIG_PXA250 264 265 266- Board Type: Define exactly one of 267 268 PowerPC based boards: 269 --------------------- 270 271 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, 272 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, 273 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, 274 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, 275 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, 276 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, 277 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, 278 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, 279 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, 280 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, 281 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, 282 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, 283 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, 284 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, 285 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, 286 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, 287 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, 288 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, 289 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, 290 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, 291 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, 292 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, 293 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, 294 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, 295 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, 296 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, 297 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, 298 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, 299 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, 300 CONFIG_EBONY, CONFIG_sacsng 301 302 ARM based boards: 303 ----------------- 304 305 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, 306 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, 307 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, 308 CONFIG_TRAB 309 310 311- CPU Module Type: (if CONFIG_COGENT is defined) 312 Define exactly one of 313 CONFIG_CMA286_60_OLD 314--- FIXME --- not tested yet: 315 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 316 CONFIG_CMA287_23, CONFIG_CMA287_50 317 318- Motherboard Type: (if CONFIG_COGENT is defined) 319 Define exactly one of 320 CONFIG_CMA101, CONFIG_CMA102 321 322- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 323 Define one or more of 324 CONFIG_CMA302 325 326- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 327 Define one or more of 328 CONFIG_LCD_HEARTBEAT - update a character position on 329 the lcd display every second with 330 a "rotator" |\-/|\-/ 331 332- MPC824X Family Member (if CONFIG_MPC824X is defined) 333 Define exactly one of 334 CONFIG_MPC8240, CONFIG_MPC8245 335 336- 8xx CPU Options: (if using an 8xx cpu) 337 Define one or more of 338 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. 339 no 32KHz reference PIT/RTC clock 340 341- Clock Interface: 342 CONFIG_CLOCKS_IN_MHZ 343 344 U-Boot stores all clock information in Hz 345 internally. For binary compatibility with older Linux 346 kernels (which expect the clocks passed in the 347 bd_info data to be in MHz) the environment variable 348 "clocks_in_mhz" can be defined so that U-Boot 349 converts clock data to MHZ before passing it to the 350 Linux kernel. 351 352 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 353 "clocks_in_mhz=1" is automatically included in the 354 default environment. 355 356- Console Interface: 357 Depending on board, define exactly one serial port 358 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 359 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 360 console by defining CONFIG_8xx_CONS_NONE 361 362 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 363 port routines must be defined elsewhere 364 (i.e. serial_init(), serial_getc(), ...) 365 366 CONFIG_CFB_CONSOLE 367 Enables console device for a color framebuffer. Needs following 368 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 369 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 370 (default big endian) 371 VIDEO_HW_RECTFILL graphic chip supports 372 rectangle fill 373 (cf. smiLynxEM) 374 VIDEO_HW_BITBLT graphic chip supports 375 bit-blit (cf. smiLynxEM) 376 VIDEO_VISIBLE_COLS visible pixel columns 377 (cols=pitch) 378 VIDEO_VISIBLE_ROWS visible pixel rows 379 VIDEO_PIXEL_SIZE bytes per pixel 380 VIDEO_DATA_FORMAT graphic data format 381 (0-5, cf. cfb_console.c) 382 VIDEO_FB_ADRS framebuffer address 383 VIDEO_KBD_INIT_FCT keyboard int fct 384 (i.e. i8042_kbd_init()) 385 VIDEO_TSTC_FCT test char fct 386 (i.e. i8042_tstc) 387 VIDEO_GETC_FCT get char fct 388 (i.e. i8042_getc) 389 CONFIG_CONSOLE_CURSOR cursor drawing on/off 390 (requires blink timer 391 cf. i8042.c) 392 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 393 CONFIG_CONSOLE_TIME display time/date info in 394 upper right corner 395 (requires CFG_CMD_DATE) 396 CONFIG_VIDEO_LOGO display Linux logo in 397 upper left corner 398 CONFIG_CONSOLE_EXTRA_INFO 399 addional board info beside 400 the logo 401 402 When CONFIG_CFB_CONSOLE is defined, video console is 403 default i/o. Serial console can be forced with 404 environment 'console=serial'. 405 406- Console Baudrate: 407 CONFIG_BAUDRATE - in bps 408 Select one of the baudrates listed in 409 CFG_BAUDRATE_TABLE, see below. 410 411- Interrupt driven serial port input: 412 CONFIG_SERIAL_SOFTWARE_FIFO 413 414 PPC405GP only. 415 Use an interrupt handler for receiving data on the 416 serial port. It also enables using hardware handshake 417 (RTS/CTS) and UART's built-in FIFO. Set the number of 418 bytes the interrupt driven input buffer should have. 419 420 Set to 0 to disable this feature (this is the default). 421 This will also disable hardware handshake. 422 423- Boot Delay: CONFIG_BOOTDELAY - in seconds 424 Delay before automatically booting the default image; 425 set to -1 to disable autoboot. 426 427 See doc/README.autoboot for these options that 428 work with CONFIG_BOOTDELAY. None are required. 429 CONFIG_BOOT_RETRY_TIME 430 CONFIG_BOOT_RETRY_MIN 431 CONFIG_AUTOBOOT_KEYED 432 CONFIG_AUTOBOOT_PROMPT 433 CONFIG_AUTOBOOT_DELAY_STR 434 CONFIG_AUTOBOOT_STOP_STR 435 CONFIG_AUTOBOOT_DELAY_STR2 436 CONFIG_AUTOBOOT_STOP_STR2 437 CONFIG_ZERO_BOOTDELAY_CHECK 438 CONFIG_RESET_TO_RETRY 439 440- Autoboot Command: 441 CONFIG_BOOTCOMMAND 442 Only needed when CONFIG_BOOTDELAY is enabled; 443 define a command string that is automatically executed 444 when no character is read on the console interface 445 within "Boot Delay" after reset. 446 447 CONFIG_BOOTARGS 448 This can be used to pass arguments to the bootm 449 command. The value of CONFIG_BOOTARGS goes into the 450 environment value "bootargs". 451 452 CONFIG_RAMBOOT and CONFIG_NFSBOOT 453 The value of these goes into the environment as 454 "ramboot" and "nfsboot" respectively, and can be used 455 as a convenience, when switching between booting from 456 ram and nfs. 457 458- Pre-Boot Commands: 459 CONFIG_PREBOOT 460 461 When this option is #defined, the existence of the 462 environment variable "preboot" will be checked 463 immediately before starting the CONFIG_BOOTDELAY 464 countdown and/or running the auto-boot command resp. 465 entering interactive mode. 466 467 This feature is especially useful when "preboot" is 468 automatically generated or modified. For an example 469 see the LWMON board specific code: here "preboot" is 470 modified when the user holds down a certain 471 combination of keys on the (special) keyboard when 472 booting the systems 473 474- Serial Download Echo Mode: 475 CONFIG_LOADS_ECHO 476 If defined to 1, all characters received during a 477 serial download (using the "loads" command) are 478 echoed back. This might be needed by some terminal 479 emulations (like "cu"), but may as well just take 480 time on others. This setting #define's the initial 481 value of the "loads_echo" environment variable. 482 483- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) 484 CONFIG_KGDB_BAUDRATE 485 Select one of the baudrates listed in 486 CFG_BAUDRATE_TABLE, see below. 487 488- Monitor Functions: 489 CONFIG_COMMANDS 490 Most monitor functions can be selected (or 491 de-selected) by adjusting the definition of 492 CONFIG_COMMANDS; to select individual functions, 493 #define CONFIG_COMMANDS by "OR"ing any of the 494 following values: 495 496 #define enables commands: 497 ------------------------- 498 CFG_CMD_ASKENV * ask for env variable 499 CFG_CMD_BDI bdinfo 500 CFG_CMD_BEDBUG Include BedBug Debugger 501 CFG_CMD_BOOTD bootd 502 CFG_CMD_CACHE icache, dcache 503 CFG_CMD_CONSOLE coninfo 504 CFG_CMD_DATE * support for RTC, date/time... 505 CFG_CMD_DHCP DHCP support 506 CFG_CMD_ECHO * echo arguments 507 CFG_CMD_EEPROM * EEPROM read/write support 508 CFG_CMD_ELF bootelf, bootvx 509 CFG_CMD_ENV saveenv 510 CFG_CMD_FDC * Floppy Disk Support 511 CFG_CMD_FLASH flinfo, erase, protect 512 CFG_CMD_FPGA FPGA device initialization support 513 CFG_CMD_I2C * I2C serial bus support 514 CFG_CMD_IDE * IDE harddisk support 515 CFG_CMD_IMI iminfo 516 CFG_CMD_IMMAP * IMMR dump support 517 CFG_CMD_IRQ * irqinfo 518 CFG_CMD_KGDB * kgdb 519 CFG_CMD_LOADB loadb 520 CFG_CMD_LOADS loads 521 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 522 loop, mtest 523 CFG_CMD_MII MII utility commands 524 CFG_CMD_NET bootp, tftpboot, rarpboot 525 CFG_CMD_PCI * pciinfo 526 CFG_CMD_PCMCIA * PCMCIA support 527 CFG_CMD_REGINFO * Register dump 528 CFG_CMD_RUN run command in env variable 529 CFG_CMD_SCSI * SCSI Support 530 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) 531 CFG_CMD_SPI * SPI serial bus support 532 CFG_CMD_USB * USB support 533 CFG_CMD_BSP * Board SPecific functions 534 ----------------------------------------------- 535 CFG_CMD_ALL all 536 537 CFG_CMD_DFL Default configuration; at the moment 538 this is includes all commands, except 539 the ones marked with "*" in the list 540 above. 541 542 If you don't define CONFIG_COMMANDS it defaults to 543 CFG_CMD_DFL in include/cmd_confdefs.h. A board can 544 override the default settings in the respective 545 include file. 546 547 EXAMPLE: If you want all functions except of network 548 support you can write: 549 550 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) 551 552 553 Note: Don't enable the "icache" and "dcache" commands 554 (configuration option CFG_CMD_CACHE) unless you know 555 what you (and your U-Boot users) are doing. Data 556 cache cannot be enabled on systems like the 8xx or 557 8260 (where accesses to the IMMR region must be 558 uncached), and it cannot be disabled on all other 559 systems where we (mis-) use the data cache to hold an 560 initial stack and some data. 561 562 563 XXX - this list needs to get updated! 564 565- Watchdog: 566 CONFIG_WATCHDOG 567 If this variable is defined, it enables watchdog 568 support. There must support in the platform specific 569 code for a watchdog. For the 8xx and 8260 CPUs, the 570 SIU Watchdog feature is enabled in the SYPCR 571 register. 572 573- Real-Time Clock: 574 575 When CFG_CMD_DATE is selected, the type of the RTC 576 has to be selected, too. Define exactly one of the 577 following options: 578 579 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 580 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 581 CONFIG_RTC_MC146818 - use MC146818 RTC 582 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 583 584- Timestamp Support: 585 586 When CONFIG_TIMESTAMP is selected, the timestamp 587 (date and time) of an image is printed by image 588 commands like bootm or iminfo. This option is 589 automatically enabled when you select CFG_CMD_DATE . 590 591- Partition Support: 592 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 593 and/or CONFIG_ISO_PARTITION 594 595 If IDE or SCSI support is enabled (CFG_CMD_IDE or 596 CFG_CMD_SCSI) you must configure support for at least 597 one partition type as well. 598 599- IDE Reset method: 600 CONFIG_IDE_RESET_ROUTINE 601 602 Set this to define that instead of a reset Pin, the 603 routine ide_set_reset(int idereset) will be used. 604 605- ATAPI Support: 606 CONFIG_ATAPI 607 608 Set this to enable ATAPI support. 609 610- SCSI Support: 611 At the moment only there is only support for the 612 SYM53C8XX SCSI controller; define 613 CONFIG_SCSI_SYM53C8XX to enable it. 614 615 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 616 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 617 CFG_SCSI_MAX_LUN] can be adjusted to define the 618 maximum numbers of LUNs, SCSI ID's and target 619 devices. 620 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 621 622- NETWORK Support (PCI): 623 CONFIG_EEPRO100 624 Support for Intel 82557/82559/82559ER chips. 625 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 626 write routine for first time initialisation. 627 628 CONFIG_TULIP 629 Support for Digital 2114x chips. 630 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 631 modem chip initialisation (KS8761/QS6611). 632 633 CONFIG_NATSEMI 634 Support for National dp83815 chips. 635 636 CONFIG_NS8382X 637 Support for National dp8382[01] gigabit chips. 638 639- USB Support: 640 At the moment only the UHCI host controller is 641 supported (PIP405, MIP405); define 642 CONFIG_USB_UHCI to enable it. 643 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 644 end define CONFIG_USB_STORAGE to enable the USB 645 storage devices. 646 Note: 647 Supported are USB Keyboards and USB Floppy drives 648 (TEAC FD-05PUB). 649 650- Keyboard Support: 651 CONFIG_ISA_KEYBOARD 652 653 Define this to enable standard (PC-Style) keyboard 654 support 655 656 CONFIG_I8042_KBD 657 Standard PC keyboard driver with US (is default) and 658 GERMAN key layout (switch via environment 'keymap=de') support. 659 Export function i8042_kbd_init, i8042_tstc and i8042_getc 660 for cfb_console. Supports cursor blinking. 661 662- Video support: 663 CONFIG_VIDEO 664 665 Define this to enable video support (for output to 666 video). 667 668 CONFIG_VIDEO_CT69000 669 670 Enable Chips & Technologies 69000 Video chip 671 672 CONFIG_VIDEO_SMI_LYNXEM 673 Enable Silicon Motion SMI 712/710/810 Video chip 674 Videomode are selected via environment 'videomode' with 675 standard LiLo mode numbers. 676 Following modes are supported (* is default): 677 678 800x600 1024x768 1280x1024 679 256 (8bit) 303* 305 307 680 65536 (16bit) 314 317 31a 681 16,7 Mill (24bit) 315 318 31b 682 (i.e. setenv videomode 317; saveenv; reset;) 683 684- LCD Support: CONFIG_LCD 685 686 Define this to enable LCD support (for output to LCD 687 display); also select one of the supported displays 688 by defining one of these: 689 690 CONFIG_NEC_NL6648AC33: 691 692 NEC NL6648AC33-18. Active, color, single scan. 693 694 CONFIG_NEC_NL6648BC20 695 696 NEC NL6648BC20-08. 6.5", 640x480. 697 Active, color, single scan. 698 699 CONFIG_SHARP_16x9 700 701 Sharp 320x240. Active, color, single scan. 702 It isn't 16x9, and I am not sure what it is. 703 704 CONFIG_SHARP_LQ64D341 705 706 Sharp LQ64D341 display, 640x480. 707 Active, color, single scan. 708 709 CONFIG_HLD1045 710 711 HLD1045 display, 640x480. 712 Active, color, single scan. 713 714 CONFIG_OPTREX_BW 715 716 Optrex CBL50840-2 NF-FW 99 22 M5 717 or 718 Hitachi LMG6912RPFC-00T 719 or 720 Hitachi SP14Q002 721 722 320x240. Black & white. 723 724 Normally display is black on white background; define 725 CFG_WHITE_ON_BLACK to get it inverted. 726 727- Ethernet address: 728 CONFIG_ETHADDR 729 CONFIG_ETH2ADDR 730 CONFIG_ETH3ADDR 731 732 Define a default value for ethernet address to use 733 for the respective ethernet interface, in case this 734 is not determined automatically. 735 736- IP address: 737 CONFIG_IPADDR 738 739 Define a default value for the IP address to use for 740 the default ethernet interface, in case this is not 741 determined through e.g. bootp. 742 743- Server IP address: 744 CONFIG_SERVERIP 745 746 Defines a default value for theIP address of a TFTP 747 server to contact when using the "tftboot" command. 748 749- BOOTP Recovery Mode: 750 CONFIG_BOOTP_RANDOM_DELAY 751 752 If you have many targets in a network that try to 753 boot using BOOTP, you may want to avoid that all 754 systems send out BOOTP requests at precisely the same 755 moment (which would happen for instance at recovery 756 from a power failure, when all systems will try to 757 boot, thus flooding the BOOTP server. Defining 758 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 759 inserted before sending out BOOTP requests. The 760 following delays are insterted then: 761 762 1st BOOTP request: delay 0 ... 1 sec 763 2nd BOOTP request: delay 0 ... 2 sec 764 3rd BOOTP request: delay 0 ... 4 sec 765 4th and following 766 BOOTP requests: delay 0 ... 8 sec 767 768- Status LED: CONFIG_STATUS_LED 769 770 Several configurations allow to display the current 771 status using a LED. For instance, the LED will blink 772 fast while running U-Boot code, stop blinking as 773 soon as a reply to a BOOTP request was received, and 774 start blinking slow once the Linux kernel is running 775 (supported by a status LED driver in the Linux 776 kernel). Defining CONFIG_STATUS_LED enables this 777 feature in U-Boot. 778 779- CAN Support: CONFIG_CAN_DRIVER 780 781 Defining CONFIG_CAN_DRIVER enables CAN driver support 782 on those systems that support this (optional) 783 feature, like the TQM8xxL modules. 784 785- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 786 787 Enables I2C serial bus commands. If this is selected, 788 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined 789 to include the appropriate I2C driver. 790 791 See also: common/cmd_i2c.c for a description of the 792 command line interface. 793 794 795 CONFIG_HARD_I2C 796 797 Selects the CPM hardware driver for I2C. 798 799 CONFIG_SOFT_I2C 800 801 Use software (aka bit-banging) driver instead of CPM 802 or similar hardware support for I2C. This is configured 803 via the following defines. 804 805 I2C_INIT 806 807 (Optional). Any commands necessary to enable I2C 808 controller or configure ports. 809 810 I2C_PORT 811 812 (Only for MPC8260 CPU). The I/O port to use (the code 813 assumes both bits are on the same port). Valid values 814 are 0..3 for ports A..D. 815 816 I2C_ACTIVE 817 818 The code necessary to make the I2C data line active 819 (driven). If the data line is open collector, this 820 define can be null. 821 822 I2C_TRISTATE 823 824 The code necessary to make the I2C data line tri-stated 825 (inactive). If the data line is open collector, this 826 define can be null. 827 828 I2C_READ 829 830 Code that returns TRUE if the I2C data line is high, 831 FALSE if it is low. 832 833 I2C_SDA(bit) 834 835 If <bit> is TRUE, sets the I2C data line high. If it 836 is FALSE, it clears it (low). 837 838 I2C_SCL(bit) 839 840 If <bit> is TRUE, sets the I2C clock line high. If it 841 is FALSE, it clears it (low). 842 843 I2C_DELAY 844 845 This delay is invoked four times per clock cycle so this 846 controls the rate of data transfer. The data rate thus 847 is 1 / (I2C_DELAY * 4). 848 849- SPI Support: CONFIG_SPI 850 851 Enables SPI driver (so far only tested with 852 SPI EEPROM, also an instance works with Crystal A/D and 853 D/As on the SACSng board) 854 855 CONFIG_SPI_X 856 857 Enables extended (16-bit) SPI EEPROM addressing. 858 (symmetrical to CONFIG_I2C_X) 859 860 CONFIG_SOFT_SPI 861 862 Enables a software (bit-bang) SPI driver rather than 863 using hardware support. This is a general purpose 864 driver that only requires three general I/O port pins 865 (two outputs, one input) to function. If this is 866 defined, the board configuration must define several 867 SPI configuration items (port pins to use, etc). For 868 an example, see include/configs/sacsng.h. 869 870- FPGA Support: CONFIG_FPGA_COUNT 871 872 Specify the number of FPGA devices to support. 873 874 CONFIG_FPGA 875 876 Used to specify the types of FPGA devices. For 877 example, 878 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 879 880 CFG_FPGA_PROG_FEEDBACK 881 882 Enable printing of hash marks during FPGA 883 configuration. 884 885 CFG_FPGA_CHECK_BUSY 886 887 Enable checks on FPGA configuration interface busy 888 status by the configuration function. This option 889 will require a board or device specific function to 890 be written. 891 892 CONFIG_FPGA_DELAY 893 894 If defined, a function that provides delays in the 895 FPGA configuration driver. 896 897 CFG_FPGA_CHECK_CTRLC 898 899 Allow Control-C to interrupt FPGA configuration 900 901 CFG_FPGA_CHECK_ERROR 902 903 Check for configuration errors during FPGA bitfile 904 loading. For example, abort during Virtex II 905 configuration if the INIT_B line goes low (which 906 indicated a CRC error). 907 908 CFG_FPGA_WAIT_INIT 909 910 Maximum time to wait for the INIT_B line to deassert 911 after PROB_B has been deasserted during a Virtex II 912 FPGA configuration sequence. The default time is 500 mS. 913 914 CFG_FPGA_WAIT_BUSY 915 916 Maximum time to wait for BUSY to deassert during 917 Virtex II FPGA configuration. The default is 5 mS. 918 919 CFG_FPGA_WAIT_CONFIG 920 921 Time to wait after FPGA configuration. The default is 922 200 mS. 923 924- FPGA Support: CONFIG_FPGA_COUNT 925 926 Specify the number of FPGA devices to support. 927 928 CONFIG_FPGA 929 930 Used to specify the types of FPGA devices. For example, 931 #define CONFIG_FPGA CFG_XILINX_VIRTEX2 932 933 CFG_FPGA_PROG_FEEDBACK 934 935 Enable printing of hash marks during FPGA configuration. 936 937 CFG_FPGA_CHECK_BUSY 938 939 Enable checks on FPGA configuration interface busy 940 status by the configuration function. This option 941 will require a board or device specific function to 942 be written. 943 944 CONFIG_FPGA_DELAY 945 946 If defined, a function that provides delays in the FPGA 947 configuration driver. 948 949 CFG_FPGA_CHECK_CTRLC 950 Allow Control-C to interrupt FPGA configuration 951 952 CFG_FPGA_CHECK_ERROR 953 954 Check for configuration errors during FPGA bitfile 955 loading. For example, abort during Virtex II 956 configuration if the INIT_B line goes low (which 957 indicated a CRC error). 958 959 CFG_FPGA_WAIT_INIT 960 961 Maximum time to wait for the INIT_B line to deassert 962 after PROB_B has been deasserted during a Virtex II 963 FPGA configuration sequence. The default time is 500 964 mS. 965 966 CFG_FPGA_WAIT_BUSY 967 968 Maximum time to wait for BUSY to deassert during 969 Virtex II FPGA configuration. The default is 5 mS. 970 971 CFG_FPGA_WAIT_CONFIG 972 973 Time to wait after FPGA configuration. The default is 974 200 mS. 975 976- Configuration Management: 977 CONFIG_IDENT_STRING 978 979 If defined, this string will be added to the U-Boot 980 version information (U_BOOT_VERSION) 981 982- Vendor Parameter Protection: 983 984 U-Boot considers the values of the environment 985 variables "serial#" (Board Serial Number) and 986 "ethaddr" (Ethernet Address) to bb parameters that 987 are set once by the board vendor / manufacturer, and 988 protects these variables from casual modification by 989 the user. Once set, these variables are read-only, 990 and write or delete attempts are rejected. You can 991 change this behviour: 992 993 If CONFIG_ENV_OVERWRITE is #defined in your config 994 file, the write protection for vendor parameters is 995 completely disabled. Anybody can change or delte 996 these parameters. 997 998 Alternatively, if you #define _both_ CONFIG_ETHADDR 999 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1000 ethernet address is installed in the environment, 1001 which can be changed exactly ONCE by the user. [The 1002 serial# is unaffected by this, i. e. it remains 1003 read-only.] 1004 1005- Protected RAM: 1006 CONFIG_PRAM 1007 1008 Define this variable to enable the reservation of 1009 "protected RAM", i. e. RAM which is not overwritten 1010 by U-Boot. Define CONFIG_PRAM to hold the number of 1011 kB you want to reserve for pRAM. You can overwrite 1012 this default value by defining an environment 1013 variable "pram" to the number of kB you want to 1014 reserve. Note that the board info structure will 1015 still show the full amount of RAM. If pRAM is 1016 reserved, a new environment variable "mem" will 1017 automatically be defined to hold the amount of 1018 remaining RAM in a form that can be passed as boot 1019 argument to Linux, for instance like that: 1020 1021 setenv bootargs ... mem=\$(mem) 1022 saveenv 1023 1024 This way you can tell Linux not to use this memory, 1025 either, which results in a memory region that will 1026 not be affected by reboots. 1027 1028 *WARNING* If your board configuration uses automatic 1029 detection of the RAM size, you must make sure that 1030 this memory test is non-destructive. So far, the 1031 following board configurations are known to be 1032 "pRAM-clean": 1033 1034 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1035 HERMES, IP860, RPXlite, LWMON, LANTEC, 1036 PCU_E, FLAGADM, TQM8260 1037 1038- Error Recovery: 1039 CONFIG_PANIC_HANG 1040 1041 Define this variable to stop the system in case of a 1042 fatal error, so that you have to reset it manually. 1043 This is probably NOT a good idea for an embedded 1044 system where you want to system to reboot 1045 automatically as fast as possible, but it may be 1046 useful during development since you can try to debug 1047 the conditions that lead to the situation. 1048 1049 CONFIG_NET_RETRY_COUNT 1050 1051 This variable defines the number of retries for 1052 network operations like ARP, RARP, TFTP, or BOOTP 1053 before giving up the operation. If not defined, a 1054 default value of 5 is used. 1055 1056- Command Interpreter: 1057 CFG_HUSH_PARSER 1058 1059 Define this variable to enable the "hush" shell (from 1060 Busybox) as command line interpreter, thus enabling 1061 powerful command line syntax like 1062 if...then...else...fi conditionals or `&&' and '||' 1063 constructs ("shell scripts"). 1064 1065 If undefined, you get the old, much simpler behaviour 1066 with a somewhat smaller memory footprint. 1067 1068 1069 CFG_PROMPT_HUSH_PS2 1070 1071 This defines the secondary prompt string, which is 1072 printed when the command interpreter needs more input 1073 to complete a command. Usually "> ". 1074 1075 Note: 1076 1077 In the current implementation, the local variables 1078 space and global environment variables space are 1079 separated. Local variables are those you define by 1080 simply typing like `name=value'. To access a local 1081 variable later on, you have write `$name' or 1082 `${name}'; variable directly by typing say `$name' at 1083 the command prompt. 1084 1085 Global environment variables are those you use 1086 setenv/printenv to work with. To run a command stored 1087 in such a variable, you need to use the run command, 1088 and you must not use the '$' sign to access them. 1089 1090 To store commands and special characters in a 1091 variable, please use double quotation marks 1092 surrounding the whole text of the variable, instead 1093 of the backslashes before semicolons and special 1094 symbols. 1095 1096- Default Environment 1097 CONFIG_EXTRA_ENV_SETTINGS 1098 1099 Define this to contain any number of null terminated 1100 strings (variable = value pairs) that will be part of 1101 the default enviroment compiled into the boot image. 1102 For example, place something like this in your 1103 board's config file: 1104 1105 #define CONFIG_EXTRA_ENV_SETTINGS \ 1106 "myvar1=value1\0" \ 1107 "myvar2=value2\0" 1108 1109 Warning: This method is based on knowledge about the 1110 internal format how the environment is stored by the 1111 U-Boot code. This is NOT an official, expoerted 1112 interface! Although it is unlikely that this format 1113 will change soon, there is no guarantee either. 1114 You better know what you are doing here. 1115 1116 Note: overly (ab)use of the default environment is 1117 discouraged. Make sure to check other ways to preset 1118 the environment like the autoscript function or the 1119 boot command first. 1120 1121- Show boot progress 1122 CONFIG_SHOW_BOOT_PROGRESS 1123 1124 Defining this option allows to add some board- 1125 specific code (calling a user-provided function 1126 "show_boot_progress(int)") that enables you to show 1127 the system's boot progress on some display (for 1128 example, some LED's) on your board. At the moment, 1129 the following checkpoints are implemented: 1130 1131 Arg Where When 1132 1 common/cmd_bootm.c before attempting to boot an image 1133 -1 common/cmd_bootm.c Image header has bad magic number 1134 2 common/cmd_bootm.c Image header has correct magic number 1135 -2 common/cmd_bootm.c Image header has bad checksum 1136 3 common/cmd_bootm.c Image header has correct checksum 1137 -3 common/cmd_bootm.c Image data has bad checksum 1138 4 common/cmd_bootm.c Image data has correct checksum 1139 -4 common/cmd_bootm.c Image is for unsupported architecture 1140 5 common/cmd_bootm.c Architecture check OK 1141 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1142 6 common/cmd_bootm.c Image Type check OK 1143 -6 common/cmd_bootm.c gunzip uncompression error 1144 -7 common/cmd_bootm.c Unimplemented compression type 1145 7 common/cmd_bootm.c Uncompression OK 1146 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1147 8 common/cmd_bootm.c Image Type check OK 1148 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1149 9 common/cmd_bootm.c Start initial ramdisk verification 1150 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1151 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1152 10 common/cmd_bootm.c Ramdisk header is OK 1153 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1154 11 common/cmd_bootm.c Ramdisk data has correct checksum 1155 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1156 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1157 13 common/cmd_bootm.c Start multifile image verification 1158 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1159 15 common/cmd_bootm.c All preparation done, transferring control to OS 1160 1161 -1 common/cmd_doc.c Bad usage of "doc" command 1162 -1 common/cmd_doc.c No boot device 1163 -1 common/cmd_doc.c Unknown Chip ID on boot device 1164 -1 common/cmd_doc.c Read Error on boot device 1165 -1 common/cmd_doc.c Image header has bad magic number 1166 1167 -1 common/cmd_ide.c Bad usage of "ide" command 1168 -1 common/cmd_ide.c No boot device 1169 -1 common/cmd_ide.c Unknown boot device 1170 -1 common/cmd_ide.c Unknown partition table 1171 -1 common/cmd_ide.c Invalid partition type 1172 -1 common/cmd_ide.c Read Error on boot device 1173 -1 common/cmd_ide.c Image header has bad magic number 1174 1175 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC 1176 1177 1178Modem Support: 1179-------------- 1180 1181[so far only for SMDK2400 board] 1182 1183- Modem support endable: 1184 CONFIG_MODEM_SUPPORT 1185 1186- RTS/CTS Flow control enable: 1187 CONFIG_HWFLOW 1188 1189- Modem debug support: 1190 CONFIG_MODEM_SUPPORT_DEBUG 1191 1192 Enables debugging stuff (char screen[1024], dbg()) 1193 for modem support. Useful only with BDI2000. 1194 1195- General: 1196 1197 In the target system modem support is enabled when a 1198 specific key (key combination) is pressed during 1199 power-on. Otherwise U-Boot will boot normally 1200 (autoboot). The key_pressed() fuction is called from 1201 board_init(). Currently key_pressed() is a dummy 1202 function, returning 1 and thus enabling modem 1203 initialization. 1204 1205 If there are no modem init strings in the 1206 environment, U-Boot proceed to autoboot; the 1207 previous output (banner, info printfs) will be 1208 supressed, though. 1209 1210 See also: doc/README.Modem 1211 1212 1213 1214 1215Configuration Settings: 1216----------------------- 1217 1218- CFG_LONGHELP: Defined when you want long help messages included; 1219 undefine this when you're short of memory. 1220 1221- CFG_PROMPT: This is what U-Boot prints on the console to 1222 prompt for user input. 1223 1224- CFG_CBSIZE: Buffer size for input from the Console 1225 1226- CFG_PBSIZE: Buffer size for Console output 1227 1228- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1229 1230- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1231 the application (usually a Linux kernel) when it is 1232 booted 1233 1234- CFG_BAUDRATE_TABLE: 1235 List of legal baudrate settings for this board. 1236 1237- CFG_CONSOLE_INFO_QUIET 1238 Suppress display of console information at boot. 1239 1240- CFG_CONSOLE_IS_IN_ENV 1241 If the board specific function 1242 extern int overwrite_console (void); 1243 returns 1, the stdin, stderr and stdout are switched to the 1244 serial port, else the settings in the environment are used. 1245 1246- CFG_CONSOLE_OVERWRITE_ROUTINE 1247 Enable the call to overwrite_console(). 1248 1249- CFG_CONSOLE_ENV_OVERWRITE 1250 Enable overwrite of previous console environment settings. 1251 1252- CFG_MEMTEST_START, CFG_MEMTEST_END: 1253 Begin and End addresses of the area used by the 1254 simple memory test. 1255 1256- CFG_ALT_MEMTEST: 1257 Enable an alternate, more extensive memory test. 1258 1259- CFG_TFTP_LOADADDR: 1260 Default load address for network file downloads 1261 1262- CFG_LOADS_BAUD_CHANGE: 1263 Enable temporary baudrate change while serial download 1264 1265- CFG_SDRAM_BASE: 1266 Physical start address of SDRAM. _Must_ be 0 here. 1267 1268- CFG_MBIO_BASE: 1269 Physical start address of Motherboard I/O (if using a 1270 Cogent motherboard) 1271 1272- CFG_FLASH_BASE: 1273 Physical start address of Flash memory. 1274 1275- CFG_MONITOR_BASE: 1276 Physical start address of boot monitor code (set by 1277 make config files to be same as the text base address 1278 (TEXT_BASE) used when linking) - same as 1279 CFG_FLASH_BASE when booting from flash. 1280 1281- CFG_MONITOR_LEN: 1282 Size of memory reserved for monitor code 1283 1284- CFG_MALLOC_LEN: 1285 Size of DRAM reserved for malloc() use. 1286 1287- CFG_BOOTMAPSZ: 1288 Maximum size of memory mapped by the startup code of 1289 the Linux kernel; all data that must be processed by 1290 the Linux kernel (bd_info, boot arguments, eventually 1291 initrd image) must be put below this limit. 1292 1293- CFG_MAX_FLASH_BANKS: 1294 Max number of Flash memory banks 1295 1296- CFG_MAX_FLASH_SECT: 1297 Max number of sectors on a Flash chip 1298 1299- CFG_FLASH_ERASE_TOUT: 1300 Timeout for Flash erase operations (in ms) 1301 1302- CFG_FLASH_WRITE_TOUT: 1303 Timeout for Flash write operations (in ms) 1304 1305- CFG_DIRECT_FLASH_TFTP: 1306 1307 Enable TFTP transfers directly to flash memory; 1308 without this option such a download has to be 1309 performed in two steps: (1) download to RAM, and (2) 1310 copy from RAM to flash. 1311 1312 The two-step approach is usually more reliable, since 1313 you can check if the download worked before you erase 1314 the flash, but in some situations (when sytem RAM is 1315 too limited to allow for a tempory copy of the 1316 downloaded image) this option may be very useful. 1317 1318- CFG_FLASH_CFI: 1319 Define if the flash driver uses extra elements in the 1320 common flash structure for storing flash geometry 1321 1322The following definitions that deal with the placement and management 1323of environment data (variable area); in general, we support the 1324following configurations: 1325 1326- CFG_ENV_IS_IN_FLASH: 1327 1328 Define this if the environment is in flash memory. 1329 1330 a) The environment occupies one whole flash sector, which is 1331 "embedded" in the text segment with the U-Boot code. This 1332 happens usually with "bottom boot sector" or "top boot 1333 sector" type flash chips, which have several smaller 1334 sectors at the start or the end. For instance, such a 1335 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1336 such a case you would place the environment in one of the 1337 4 kB sectors - with U-Boot code before and after it. With 1338 "top boot sector" type flash chips, you would put the 1339 environment in one of the last sectors, leaving a gap 1340 between U-Boot and the environment. 1341 1342 - CFG_ENV_OFFSET: 1343 1344 Offset of environment data (variable area) to the 1345 beginning of flash memory; for instance, with bottom boot 1346 type flash chips the second sector can be used: the offset 1347 for this sector is given here. 1348 1349 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1350 1351 - CFG_ENV_ADDR: 1352 1353 This is just another way to specify the start address of 1354 the flash sector containing the environment (instead of 1355 CFG_ENV_OFFSET). 1356 1357 - CFG_ENV_SECT_SIZE: 1358 1359 Size of the sector containing the environment. 1360 1361 1362 b) Sometimes flash chips have few, equal sized, BIG sectors. 1363 In such a case you don't want to spend a whole sector for 1364 the environment. 1365 1366 - CFG_ENV_SIZE: 1367 1368 If you use this in combination with CFG_ENV_IS_IN_FLASH 1369 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1370 of this flash sector for the environment. This saves 1371 memory for the RAM copy of the environment. 1372 1373 It may also save flash memory if you decide to use this 1374 when your environment is "embedded" within U-Boot code, 1375 since then the remainder of the flash sector could be used 1376 for U-Boot code. It should be pointed out that this is 1377 STRONGLY DISCOURAGED from a robustness point of view: 1378 updating the environment in flash makes it always 1379 necessary to erase the WHOLE sector. If something goes 1380 wrong before the contents has been restored from a copy in 1381 RAM, your target system will be dead. 1382 1383 - CFG_ENV_ADDR_REDUND 1384 CFG_ENV_SIZE_REDUND 1385 1386 These settings describe a second storage area used to hold 1387 a redundand copy of the environment data, so that there is 1388 a valid backup copy in case there is a power failur during 1389 a "saveenv" operation. 1390 1391BE CAREFUL! Any changes to the flash layout, and some changes to the 1392source code will make it necessary to adapt <board>/u-boot.lds* 1393accordingly! 1394 1395 1396- CFG_ENV_IS_IN_NVRAM: 1397 1398 Define this if you have some non-volatile memory device 1399 (NVRAM, battery buffered SRAM) which you want to use for the 1400 environment. 1401 1402 - CFG_ENV_ADDR: 1403 - CFG_ENV_SIZE: 1404 1405 These two #defines are used to determin the memory area you 1406 want to use for environment. It is assumed that this memory 1407 can just be read and written to, without any special 1408 provision. 1409 1410BE CAREFUL! The first access to the environment happens quite early 1411in U-Boot initalization (when we try to get the setting of for the 1412console baudrate). You *MUST* have mappend your NVRAM area then, or 1413U-Boot will hang. 1414 1415Please note that even with NVRAM we still use a copy of the 1416environment in RAM: we could work on NVRAM directly, but we want to 1417keep settings there always unmodified except somebody uses "saveenv" 1418to save the current settings. 1419 1420 1421- CFG_ENV_IS_IN_EEPROM: 1422 1423 Use this if you have an EEPROM or similar serial access 1424 device and a driver for it. 1425 1426 - CFG_ENV_OFFSET: 1427 - CFG_ENV_SIZE: 1428 1429 These two #defines specify the offset and size of the 1430 environment area within the total memory of your EEPROM. 1431 1432 - CFG_I2C_EEPROM_ADDR: 1433 If defined, specified the chip address of the EEPROM device. 1434 The default address is zero. 1435 1436 - CFG_EEPROM_PAGE_WRITE_BITS: 1437 If defined, the number of bits used to address bytes in a 1438 single page in the EEPROM device. A 64 byte page, for example 1439 would require six bits. 1440 1441 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1442 If defined, the number of milliseconds to delay between 1443 page writes. The default is zero milliseconds. 1444 1445 - CFG_I2C_EEPROM_ADDR_LEN: 1446 The length in bytes of the EEPROM memory array address. Note 1447 that this is NOT the chip address length! 1448 1449 - CFG_EEPROM_SIZE: 1450 The size in bytes of the EEPROM device. 1451 1452 - CFG_I2C_EEPROM_ADDR: 1453 If defined, specified the chip address of the EEPROM device. 1454 The default address is zero. 1455 1456 - CFG_EEPROM_PAGE_WRITE_BITS: 1457 If defined, the number of bits used to address bytes in a 1458 single page in the EEPROM device. A 64 byte page, for example 1459 would require six bits. 1460 1461 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 1462 If defined, the number of milliseconds to delay between 1463 page writes. The default is zero milliseconds. 1464 1465 - CFG_I2C_EEPROM_ADDR_LEN: 1466 The length in bytes of the EEPROM memory array address. Note 1467 that this is NOT the chip address length! 1468 1469 - CFG_EEPROM_SIZE: 1470 The size in bytes of the EEPROM device. 1471 1472- CFG_SPI_INIT_OFFSET 1473 1474 Defines offset to the initial SPI buffer area in DPRAM. The 1475 area is used at an early stage (ROM part) if the environment 1476 is configured to reside in the SPI EEPROM: We need a 520 byte 1477 scratch DPRAM area. It is used between the two initialization 1478 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 1479 to be a good choice since it makes it far enough from the 1480 start of the data area as well as from the stack pointer. 1481 1482Please note that the environment is read-only as long as the monitor 1483has been relocated to RAM and a RAM copy of the environment has been 1484created; also, when using EEPROM you will have to use getenv_r() 1485until then to read environment variables. 1486 1487The environment is now protected by a CRC32 checksum. Before the 1488monitor is relocated into RAM, as a result of a bad CRC you will be 1489working with the compiled-in default environment - *silently*!!! 1490[This is necessary, because the first environment variable we need is 1491the "baudrate" setting for the console - if we have a bad CRC, we 1492don't have any device yet where we could complain.] 1493 1494Note: once the monitor has been relocated, then it will complain if 1495the default environment is used; a new CRC is computed as soon as you 1496use the "setenv" command to modify / delete / add any environment 1497variable [even when you try to delete a non-existing variable!]. 1498 1499Note2: you must edit your u-boot.lds file to reflect this 1500configuration. 1501 1502 1503Many of the options are named exactly as the corresponding Linux 1504kernel configuration options. The intention is to make it easier to 1505build a config tool - later. 1506 1507Low Level (hardware related) configuration options: 1508 1509- CFG_CACHELINE_SIZE: 1510 Cache Line Size of the CPU. 1511 1512- CFG_DEFAULT_IMMR: 1513 Default address of the IMMR after system reset. 1514 Needed on some 8260 systems (MPC8260ADS and RPXsuper) 1515 to be able to adjust the position of the IMMR 1516 register after a reset. 1517 1518- CFG_IMMR: Physical address of the Internal Memory Mapped 1519 Register; DO NOT CHANGE! (11-4) 1520 [MPC8xx systems only] 1521 1522- CFG_INIT_RAM_ADDR: 1523 1524 Start address of memory area tha can be used for 1525 initial data and stack; please note that this must be 1526 writable memory that is working WITHOUT special 1527 initialization, i. e. you CANNOT use normal RAM which 1528 will become available only after programming the 1529 memory controller and running certain initialization 1530 sequences. 1531 1532 U-Boot uses the following memory types: 1533 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 1534 - MPC824X: data cache 1535 - PPC4xx: data cache 1536 1537- CFG_INIT_DATA_OFFSET: 1538 1539 Offset of the initial data structure in the memory 1540 area defined by CFG_INIT_RAM_ADDR. Usually 1541 CFG_INIT_DATA_OFFSET is chosen such that the initial 1542 data is located at the end of the available space 1543 (sometimes written as (CFG_INIT_RAM_END - 1544 CFG_INIT_DATA_SIZE), and the initial stack is just 1545 below that area (growing from (CFG_INIT_RAM_ADDR + 1546 CFG_INIT_DATA_OFFSET) downward. 1547 1548 Note: 1549 On the MPC824X (or other systems that use the data 1550 cache for initial memory) the address chosen for 1551 CFG_INIT_RAM_ADDR is basically arbitrary - it must 1552 point to an otherwise UNUSED address space between 1553 the top of RAM and the start of the PCI space. 1554 1555- CFG_SIUMCR: SIU Module Configuration (11-6) 1556 1557- CFG_SYPCR: System Protection Control (11-9) 1558 1559- CFG_TBSCR: Time Base Status and Control (11-26) 1560 1561- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 1562 1563- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 1564 1565- CFG_SCCR: System Clock and reset Control Register (15-27) 1566 1567- CFG_OR_TIMING_SDRAM: 1568 SDRAM timing 1569 1570- CFG_MAMR_PTA: 1571 periodic timer for refresh 1572 1573- CFG_DER: Debug Event Register (37-47) 1574 1575- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 1576 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 1577 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 1578 CFG_BR1_PRELIM: 1579 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 1580 1581- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 1582 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 1583 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 1584 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 1585 1586- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 1587 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 1588 Machine Mode Register and Memory Periodic Timer 1589 Prescaler definitions (SDRAM timing) 1590 1591- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 1592 enable I2C microcode relocation patch (MPC8xx); 1593 define relocation offset in DPRAM [DSP2] 1594 1595- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 1596 enable SPI microcode relocation patch (MPC8xx); 1597 define relocation offset in DPRAM [SCC4] 1598 1599- CFG_USE_OSCCLK: 1600 Use OSCM clock mode on MBX8xx board. Be careful, 1601 wrong setting might damage your board. Read 1602 doc/README.MBX before setting this variable! 1603 1604Building the Software: 1605====================== 1606 1607Building U-Boot has been tested in native PPC environments (on a 1608PowerBook G3 running LinuxPPC 2000) and in cross environments 1609(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 1610NetBSD 1.5 on x86). 1611 1612If you are not using a native PPC environment, it is assumed that you 1613have the GNU cross compiling tools available in your path and named 1614with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 1615you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 1616the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 1617change it to: 1618 1619 CROSS_COMPILE = ppc_4xx- 1620 1621 1622U-Boot is intended to be simple to build. After installing the 1623sources you must configure U-Boot for one specific board type. This 1624is done by typing: 1625 1626 make NAME_config 1627 1628where "NAME_config" is the name of one of the existing 1629configurations; the following names are supported: 1630 1631 ADCIOP_config GTH_config TQM850L_config 1632 ADS860_config IP860_config TQM855L_config 1633 AR405_config IVML24_config TQM860L_config 1634 CANBT_config IVMS8_config WALNUT405_config 1635 CPCI405_config LANTEC_config cogent_common_config 1636 CPCIISER4_config MBX_config cogent_mpc8260_config 1637 CU824_config MBX860T_config cogent_mpc8xx_config 1638 ESTEEM192E_config RPXlite_config hermes_config 1639 ETX094_config RPXsuper_config hymod_config 1640 FADS823_config SM850_config lwmon_config 1641 FADS850SAR_config SPD823TS_config pcu_e_config 1642 FADS860T_config SXNI855T_config rsdproto_config 1643 FPS850L_config Sandpoint8240_config sbc8260_config 1644 GENIETV_config TQM823L_config PIP405_config 1645 GEN860T_config EBONY_config 1646 1647Note: for some board special configuration names may exist; check if 1648 additional information is available from the board vendor; for 1649 instance, the TQM8xxL systems run normally at 50 MHz and use a 1650 SCC for 10baseT ethernet; there are also systems with 80 MHz 1651 CPU clock, and an optional Fast Ethernet module is available 1652 for CPU's with FEC. You can select such additional "features" 1653 when chosing the configuration, i. e. 1654 1655 make TQM860L_config 1656 - will configure for a plain TQM860L, i. e. 50MHz, no FEC 1657 1658 make TQM860L_FEC_config 1659 - will configure for a TQM860L at 50MHz with FEC for ethernet 1660 1661 make TQM860L_80MHz_config 1662 - will configure for a TQM860L at 80 MHz, with normal 10baseT 1663 interface 1664 1665 make TQM860L_FEC_80MHz_config 1666 - will configure for a TQM860L at 80 MHz with FEC for ethernet 1667 1668 make TQM823L_LCD_config 1669 - will configure for a TQM823L with U-Boot console on LCD 1670 1671 make TQM823L_LCD_80MHz_config 1672 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD 1673 1674 etc. 1675 1676 1677 1678Finally, type "make all", and you should get some working U-Boot 1679images ready for downlod to / installation on your system: 1680 1681- "u-boot.bin" is a raw binary image 1682- "u-boot" is an image in ELF binary format 1683- "u-boot.srec" is in Motorola S-Record format 1684 1685 1686Please be aware that the Makefiles assume you are using GNU make, so 1687for instance on NetBSD you might need to use "gmake" instead of 1688native "make". 1689 1690 1691If the system board that you have is not listed, then you will need 1692to port U-Boot to your hardware platform. To do this, follow these 1693steps: 1694 16951. Add a new configuration option for your board to the toplevel 1696 "Makefile", using the existing entries as examples. 16972. Create a new directory to hold your board specific code. Add any 1698 files you need. 16993. If you're porting U-Boot to a new CPU, then also create a new 1700 directory to hold your CPU specific code. Add any files you need. 17014. Run "make config_name" with your new name. 17025. Type "make", and you should get a working "u-boot.srec" file 1703 to be installed on your target system. 1704 [Of course, this last step is much harder than it sounds.] 1705 1706 1707Testing of U-Boot Modifications, Ports to New Hardware, etc.: 1708============================================================== 1709 1710If you have modified U-Boot sources (for instance added a new board 1711or support for new devices, a new CPU, etc.) you are expected to 1712provide feedback to the other developers. The feedback normally takes 1713the form of a "patch", i. e. a context diff against a certain (latest 1714official or latest in CVS) version of U-Boot sources. 1715 1716But before you submit such a patch, please verify that your modifi- 1717cation did not break existing code. At least make sure that *ALL* of 1718the supported boards compile WITHOUT ANY compiler warnings. To do so, 1719just run the "MAKEALL" script, which will configure and build U-Boot 1720for ALL supported system. Be warned, this will take a while. You can 1721select which (cross) compiler to use py passing a `CROSS_COMPILE' 1722environment variable to the script, i. e. to use the cross tools from 1723MontaVista's Hard Hat Linux you can type 1724 1725 CROSS_COMPILE=ppc_8xx- MAKEALL 1726 1727or to build on a native PowerPC system you can type 1728 1729 CROSS_COMPILE=' ' MAKEALL 1730 1731See also "U-Boot Porting Guide" below. 1732 1733 1734 1735Monitor Commands - Overview: 1736============================ 1737 1738go - start application at address 'addr' 1739run - run commands in an environment variable 1740bootm - boot application image from memory 1741bootp - boot image via network using BootP/TFTP protocol 1742tftpboot- boot image via network using TFTP protocol 1743 and env variables "ipaddr" and "serverip" 1744 (and eventually "gatewayip") 1745rarpboot- boot image via network using RARP/TFTP protocol 1746diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 1747loads - load S-Record file over serial line 1748loadb - load binary file over serial line (kermit mode) 1749md - memory display 1750mm - memory modify (auto-incrementing) 1751nm - memory modify (constant address) 1752mw - memory write (fill) 1753cp - memory copy 1754cmp - memory compare 1755crc32 - checksum calculation 1756imd - i2c memory display 1757imm - i2c memory modify (auto-incrementing) 1758inm - i2c memory modify (constant address) 1759imw - i2c memory write (fill) 1760icrc32 - i2c checksum calculation 1761iprobe - probe to discover valid I2C chip addresses 1762iloop - infinite loop on address range 1763isdram - print SDRAM configuration information 1764sspi - SPI utility commands 1765base - print or set address offset 1766printenv- print environment variables 1767setenv - set environment variables 1768saveenv - save environment variables to persistent storage 1769protect - enable or disable FLASH write protection 1770erase - erase FLASH memory 1771flinfo - print FLASH memory information 1772bdinfo - print Board Info structure 1773iminfo - print header information for application image 1774coninfo - print console devices and informations 1775ide - IDE sub-system 1776loop - infinite loop on address range 1777mtest - simple RAM test 1778icache - enable or disable instruction cache 1779dcache - enable or disable data cache 1780reset - Perform RESET of the CPU 1781echo - echo args to console 1782version - print monitor version 1783help - print online help 1784? - alias for 'help' 1785 1786 1787Monitor Commands - Detailed Description: 1788======================================== 1789 1790TODO. 1791 1792For now: just type "help <command>". 1793 1794 1795Environment Variables: 1796====================== 1797 1798U-Boot supports user configuration using Environment Variables which 1799can be made persistent by saving to Flash memory. 1800 1801Environment Variables are set using "setenv", printed using 1802"printenv", and saved to Flash using "saveenv". Using "setenv" 1803without a value can be used to delete a variable from the 1804environment. As long as you don't save the environment you are 1805working with an in-memory copy. In case the Flash area containing the 1806environment is erased by accident, a default environment is provided. 1807 1808Some configuration options can be set using Environment Variables: 1809 1810 baudrate - see CONFIG_BAUDRATE 1811 1812 bootdelay - see CONFIG_BOOTDELAY 1813 1814 bootcmd - see CONFIG_BOOTCOMMAND 1815 1816 bootargs - Boot arguments when booting an RTOS image 1817 1818 bootfile - Name of the image to load with TFTP 1819 1820 autoload - if set to "no" (any string beginning with 'n'), 1821 "bootp" will just load perform a lookup of the 1822 configuration from the BOOTP server, but not try to 1823 load any image using TFTP 1824 1825 autostart - if set to "yes", an image loaded using the "bootp", 1826 "rarpboot", "tftpboot" or "diskboot" commands will 1827 be automatically started (by internally calling 1828 "bootm") 1829 1830 initrd_high - restrict positioning of initrd images: 1831 If this variable is not set, initrd images will be 1832 copied to the highest possible address in RAM; this 1833 is usually what you want since it allows for 1834 maximum initrd size. If for some reason you want to 1835 make sure that the initrd image is loaded below the 1836 CFG_BOOTMAPSZ limit, you can set this environment 1837 variable to a value of "no" or "off" or "0". 1838 Alternatively, you can set it to a maximum upper 1839 address to use (U-Boot will still check that it 1840 does not overwrite the U-Boot stack and data). 1841 1842 For instance, when you have a system with 16 MB 1843 RAM, and want to reseve 4 MB from use by Linux, 1844 you can do this by adding "mem=12M" to the value of 1845 the "bootargs" variable. However, now you must make 1846 sure, that the initrd image is placed in the first 1847 12 MB as well - this can be done with 1848 1849 setenv initrd_high 00c00000 1850 1851 ipaddr - IP address; needed for tftpboot command 1852 1853 loadaddr - Default load address for commands like "bootp", 1854 "rarpboot", "tftpboot" or "diskboot" 1855 1856 loads_echo - see CONFIG_LOADS_ECHO 1857 1858 serverip - TFTP server IP address; needed for tftpboot command 1859 1860 bootretry - see CONFIG_BOOT_RETRY_TIME 1861 1862 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 1863 1864 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 1865 1866 1867The following environment variables may be used and automatically 1868updated by the network boot commands ("bootp" and "rarpboot"), 1869depending the information provided by your boot server: 1870 1871 bootfile - see above 1872 dnsip - IP address of your Domain Name Server 1873 gatewayip - IP address of the Gateway (Router) to use 1874 hostname - Target hostname 1875 ipaddr - see above 1876 netmask - Subnet Mask 1877 rootpath - Pathname of the root filesystem on the NFS server 1878 serverip - see above 1879 1880 1881There are two special Environment Variables: 1882 1883 serial# - contains hardware identification information such 1884 as type string and/or serial number 1885 ethaddr - Ethernet address 1886 1887These variables can be set only once (usually during manufacturing of 1888the board). U-Boot refuses to delete or overwrite these variables 1889once they have been set once. 1890 1891 1892Please note that changes to some configuration parameters may take 1893only effect after the next boot (yes, that's just like Windoze :-). 1894 1895 1896Note for Redundant Ethernet Interfaces: 1897======================================= 1898 1899Some boards come with redundand ethernet interfaces; U-Boot supports 1900such configurations and is capable of automatic selection of a 1901"working" interface when needed. MAC assignemnt works as follows: 1902 1903Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 1904MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 1905"eth1addr" (=>eth1), "eth2addr", ... 1906 1907If the network interface stores some valid MAC address (for instance 1908in SROM), this is used as default address if there is NO correspon- 1909ding setting in the environment; if the corresponding environment 1910variable is set, this overrides the settings in the card; that means: 1911 1912o If the SROM has a valid MAC address, and there is no address in the 1913 environment, the SROM's address is used. 1914 1915o If there is no valid address in the SROM, and a definition in the 1916 environment exists, then the value from the environment variable is 1917 used. 1918 1919o If both the SROM and the environment contain a MAC address, and 1920 both addresses are the same, this MAC address is used. 1921 1922o If both the SROM and the environment contain a MAC address, and the 1923 addresses differ, the value from the environment is used and a 1924 warning is printed. 1925 1926o If neither SROM nor the environment contain a MAC address, an error 1927 is raised. 1928 1929 1930 1931Image Formats: 1932============== 1933 1934The "boot" commands of this monitor operate on "image" files which 1935can be basicly anything, preceeded by a special header; see the 1936definitions in include/image.h for details; basicly, the header 1937defines the following image properties: 1938 1939* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 1940 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 1941 LynxOS, pSOS, QNX; 1942 Currently supported: Linux, NetBSD, VxWorks, QNX). 1943* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 1944 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 1945 Currently supported: PowerPC). 1946* Compression Type (Provisions for uncompressed, gzip, bzip2; 1947 Currently supported: uncompressed, gzip). 1948* Load Address 1949* Entry Point 1950* Image Name 1951* Image Timestamp 1952 1953The header is marked by a special Magic Number, and both the header 1954and the data portions of the image are secured against corruption by 1955CRC32 checksums. 1956 1957 1958Linux Support: 1959============== 1960 1961Although U-Boot should support any OS or standalone application 1962easily, Linux has always been in the focus during the design of 1963U-Boot. 1964 1965U-Boot includes many features that so far have been part of some 1966special "boot loader" code within the Linux kernel. Also, any 1967"initrd" images to be used are no longer part of one big Linux image; 1968instead, kernel and "initrd" are separate images. This implementation 1969serves serveral purposes: 1970 1971- the same features can be used for other OS or standalone 1972 applications (for instance: using compressed images to reduce the 1973 Flash memory footprint) 1974 1975- it becomes much easier to port new Linux kernel versions because 1976 lots of low-level, hardware dependend stuff are done by U-Boot 1977 1978- the same Linux kernel image can now be used with different "initrd" 1979 images; of course this also means that different kernel images can 1980 be run with the same "initrd". This makes testing easier (you don't 1981 have to build a new "zImage.initrd" Linux image when you just 1982 change a file in your "initrd"). Also, a field-upgrade of the 1983 software is easier now. 1984 1985 1986Linux HOWTO: 1987============ 1988 1989Porting Linux to U-Boot based systems: 1990--------------------------------------- 1991 1992U-Boot cannot save you from doing all the necessary modifications to 1993configure the Linux device drivers for use with your target hardware 1994(no, we don't intend to provide a full virtual machine interface to 1995Linux :-). 1996 1997But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 1998 1999Just make sure your machine specific header file (for instance 2000include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2001Information structure as we define in include/u-boot.h, and make 2002sure that your definition of IMAP_ADDR uses the same value as your 2003U-Boot configuration in CFG_IMMR. 2004 2005 2006Configuring the Linux kernel: 2007----------------------------- 2008 2009No specific requirements for U-Boot. Make sure you have some root 2010device (initial ramdisk, NFS) for your target system. 2011 2012 2013Building a Linux Image: 2014----------------------- 2015 2016No specific requirements for U-Boot. There is no need to add a 2017"ramdisk.image.gz" file when building the kernel, even when you 2018intend to run it with initial ramdisk. 2019 2020Example: 2021 2022 make TQM850L_config 2023 make oldconfig 2024 make dep 2025 make zImage 2026 2027However, we don't use the 'zImage' (= 'arch/ppc/mbxboot/zvmlinux') we 2028build this way. The 'zImage' includes the old boot loader code which 2029we don't ned any more. Instead, we use the raw (compressed) Linux 2030kernel image in 'arch/ppc/coffboot/vmlinux.gz'. 2031 2032There is a special tool (in 'tools/mkimage') to encapsulate this 2033image with header information, CRC32 checksum etc. for use with 2034U-Boot: 2035 2036In the first form (with "-l" option) mkimage lists the information 2037contained in the header of an existing U-Boot image; this includes 2038checksum verification: 2039 2040 tools/mkimage -l image 2041 -l ==> list image header information 2042 2043The second form (with "-d" option) is used to build a U-Boot image 2044from a "data file" which is used as image payload: 2045 2046 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2047 -n name -d data_file image 2048 -A ==> set architecture to 'arch' 2049 -O ==> set operating system to 'os' 2050 -T ==> set image type to 'type' 2051 -C ==> set compression type 'comp' 2052 -a ==> set load address to 'addr' (hex) 2053 -e ==> set entry point to 'ep' (hex) 2054 -n ==> set image name to 'name' 2055 -d ==> use image data from 'datafile' 2056 2057Right now, all Linux kernels use the same load address (0x00000000), 2058but the entry point address depends on the kernel version: 2059 2060- 2.2.x kernels have the entry point at 0x0000000C, 2061- 2.3.x and 2.4.x kernels have the entry point at 0x00000000. 2062 2063So a typical call to build a U-Boot image would read: 2064 2065 -> tools/mkimage -n '2.2.13 for initrd on TQM850L' \ 2066 > -A ppc -O linux -T kernel -C gzip -a 00000000 -e 0000000C \ 2067 > -d /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux.gz \ 2068 > examples/image-2.2.13-initrd 2069 Image Name: 2.2.13 for initrd on TQM850L 2070 Created: Wed Jul 19 02:34:59 2000 2071 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2072 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2073 Load Address: 0x00000000 2074 Entry Point: 0x0000000c 2075 2076To verify the contents of the image (or check for corruption): 2077 2078 -> tools/mkimage -l examples/image-2.2.13-initrd 2079 Image Name: 2.2.13 for initrd on TQM850L 2080 Created: Wed Jul 19 02:34:59 2000 2081 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2082 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2083 Load Address: 0x00000000 2084 Entry Point: 0x0000000c 2085 2086NOTE: for embedded systems where boot time is critical you can trade 2087speed for memory and install an UNCOMPRESSED image instead: this 2088needs more space in Flash, but boots much faster since it does not 2089need to be uncompressed: 2090 2091 -> gunzip /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux.gz 2092 -> tools/mkimage -n '2.2.13 for initrd on TQM850L' \ 2093 > -A ppc -O linux -T kernel -C none -a 00000000 -e 0000000C \ 2094 > -d /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux \ 2095 > examples/image-2.2.13-initrd-uncompressed 2096 Image Name: 2.2.13 for initrd on TQM850L 2097 Created: Wed Jul 19 02:34:59 2000 2098 Image Type: PowerPC Linux Kernel Image (uncompressed) 2099 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 2100 Load Address: 0x00000000 2101 Entry Point: 0x0000000c 2102 2103 2104Similar you can build U-Boot images from a 'ramdisk.image.gz' file 2105when your kernel is intended to use an initial ramdisk: 2106 2107 -> tools/mkimage -n 'Simple Ramdisk Image' \ 2108 > -A ppc -O linux -T ramdisk -C gzip \ 2109 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 2110 Image Name: Simple Ramdisk Image 2111 Created: Wed Jan 12 14:01:50 2000 2112 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2113 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 2114 Load Address: 0x00000000 2115 Entry Point: 0x00000000 2116 2117 2118Installing a Linux Image: 2119------------------------- 2120 2121To downloading a U-Boot image over the serial (console) interface, 2122you must convert the image to S-Record format: 2123 2124 objcopy -I binary -O srec examples/image examples/image.srec 2125 2126The 'objcopy' does not understand the information in the U-Boot 2127image header, so the resulting S-Record file will be relative to 2128address 0x00000000. To load it to a given address, you need to 2129specify the target address as 'offset' parameter with the 'loads' 2130command. 2131 2132Example: install the image to address 0x40100000 (which on the 2133TQM8xxL is in the first Flash bank): 2134 2135 => erase 40100000 401FFFFF 2136 2137 .......... done 2138 Erased 8 sectors 2139 2140 => loads 40100000 2141 ## Ready for S-Record download ... 2142 ~>examples/image.srec 2143 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 2144 ... 2145 15989 15990 15991 15992 2146 [file transfer complete] 2147 [connected] 2148 ## Start Addr = 0x00000000 2149 2150 2151You can check the success of the download using the 'iminfo' command; 2152this includes a checksum verification so you can be sure no data 2153corruption happened: 2154 2155 => imi 40100000 2156 2157 ## Checking Image at 40100000 ... 2158 Image Name: 2.2.13 for initrd on TQM850L 2159 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2160 Data Size: 335725 Bytes = 327 kB = 0 MB 2161 Load Address: 00000000 2162 Entry Point: 0000000c 2163 Verifying Checksum ... OK 2164 2165 2166 2167Boot Linux: 2168----------- 2169 2170The "bootm" command is used to boot an application that is stored in 2171memory (RAM or Flash). In case of a Linux kernel image, the contents 2172of the "bootargs" environment variable is passed to the kernel as 2173parameters. You can check and modify this variable using the 2174"printenv" and "setenv" commands: 2175 2176 2177 => printenv bootargs 2178 bootargs=root=/dev/ram 2179 2180 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2181 2182 => printenv bootargs 2183 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2184 2185 => bootm 40020000 2186 ## Booting Linux kernel at 40020000 ... 2187 Image Name: 2.2.13 for NFS on TQM850L 2188 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2189 Data Size: 381681 Bytes = 372 kB = 0 MB 2190 Load Address: 00000000 2191 Entry Point: 0000000c 2192 Verifying Checksum ... OK 2193 Uncompressing Kernel Image ... OK 2194 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 2195 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 2196 time_init: decrementer frequency = 187500000/60 2197 Calibrating delay loop... 49.77 BogoMIPS 2198 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 2199 ... 2200 2201If you want to boot a Linux kernel with initial ram disk, you pass 2202the memory addreses of both the kernel and the initrd image (PPBCOOT 2203format!) to the "bootm" command: 2204 2205 => imi 40100000 40200000 2206 2207 ## Checking Image at 40100000 ... 2208 Image Name: 2.2.13 for initrd on TQM850L 2209 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2210 Data Size: 335725 Bytes = 327 kB = 0 MB 2211 Load Address: 00000000 2212 Entry Point: 0000000c 2213 Verifying Checksum ... OK 2214 2215 ## Checking Image at 40200000 ... 2216 Image Name: Simple Ramdisk Image 2217 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2218 Data Size: 566530 Bytes = 553 kB = 0 MB 2219 Load Address: 00000000 2220 Entry Point: 00000000 2221 Verifying Checksum ... OK 2222 2223 => bootm 40100000 40200000 2224 ## Booting Linux kernel at 40100000 ... 2225 Image Name: 2.2.13 for initrd on TQM850L 2226 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2227 Data Size: 335725 Bytes = 327 kB = 0 MB 2228 Load Address: 00000000 2229 Entry Point: 0000000c 2230 Verifying Checksum ... OK 2231 Uncompressing Kernel Image ... OK 2232 ## Loading RAMDisk Image at 40200000 ... 2233 Image Name: Simple Ramdisk Image 2234 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 2235 Data Size: 566530 Bytes = 553 kB = 0 MB 2236 Load Address: 00000000 2237 Entry Point: 00000000 2238 Verifying Checksum ... OK 2239 Loading Ramdisk ... OK 2240 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 2241 Boot arguments: root=/dev/ram 2242 time_init: decrementer frequency = 187500000/60 2243 Calibrating delay loop... 49.77 BogoMIPS 2244 ... 2245 RAMDISK: Compressed image found at block 0 2246 VFS: Mounted root (ext2 filesystem). 2247 2248 bash# 2249 2250 2251Standalone HOWTO: 2252================= 2253 2254One of the features of U-Boot is that you can dynamically load and 2255run "standalone" applications, which can use some resources of 2256U-Boot like console I/O functions or interrupt services. 2257 2258Two simple examples are included with the sources: 2259 2260"Hello World" Demo: 2261------------------- 2262 2263'examples/hello_world.c' contains a small "Hello World" Demo 2264application; it is automatically compiled when you build U-Boot. 2265It's configured to run at address 0x00040004, so you can play with it 2266like that: 2267 2268 => loads 2269 ## Ready for S-Record download ... 2270 ~>examples/hello_world.srec 2271 1 2 3 4 5 6 7 8 9 10 11 ... 2272 [file transfer complete] 2273 [connected] 2274 ## Start Addr = 0x00040004 2275 2276 => go 40004 Hello World! This is a test. 2277 ## Starting application at 0x00040004 ... 2278 Hello World 2279 argc = 7 2280 argv[0] = "40004" 2281 argv[1] = "Hello" 2282 argv[2] = "World!" 2283 argv[3] = "This" 2284 argv[4] = "is" 2285 argv[5] = "a" 2286 argv[6] = "test." 2287 argv[7] = "<NULL>" 2288 Hit any key to exit ... 2289 2290 ## Application terminated, rc = 0x0 2291 2292Another example, which demonstrates how to register a CPM interrupt 2293handler with the U-Boot code, can be found in 'examples/timer.c'. 2294Here, a CPM timer is set up to generate an interrupt every second. 2295The interrupt service routine is trivial, just printing a '.' 2296character, but this is just a demo program. The application can be 2297controlled by the following keys: 2298 2299 ? - print current values og the CPM Timer registers 2300 b - enable interrupts and start timer 2301 e - stop timer and disable interrupts 2302 q - quit application 2303 2304 => loads 2305 ## Ready for S-Record download ... 2306 ~>examples/timer.srec 2307 1 2 3 4 5 6 7 8 9 10 11 ... 2308 [file transfer complete] 2309 [connected] 2310 ## Start Addr = 0x00040004 2311 2312 => go 40004 2313 ## Starting application at 0x00040004 ... 2314 TIMERS=0xfff00980 2315 Using timer 1 2316 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 2317 2318Hit 'b': 2319 [q, b, e, ?] Set interval 1000000 us 2320 Enabling timer 2321Hit '?': 2322 [q, b, e, ?] ........ 2323 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 2324Hit '?': 2325 [q, b, e, ?] . 2326 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 2327Hit '?': 2328 [q, b, e, ?] . 2329 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 2330Hit '?': 2331 [q, b, e, ?] . 2332 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 2333Hit 'e': 2334 [q, b, e, ?] ...Stopping timer 2335Hit 'q': 2336 [q, b, e, ?] ## Application terminated, rc = 0x0 2337 2338 2339NetBSD Notes: 2340============= 2341 2342Starting at version 0.9.2, U-Boot supports NetBSD both as host 2343(build U-Boot) and target system (boots NetBSD/mpc8xx). 2344 2345Building requires a cross environment; it is known to work on 2346NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 2347need gmake since the Makefiles are not compatible with BSD make). 2348Note that the cross-powerpc package does not install include files; 2349attempting to build U-Boot will fail because <machine/ansi.h> is 2350missing. This file has to be installed and patched manually: 2351 2352 # cd /usr/pkg/cross/powerpc-netbsd/include 2353 # mkdir powerpc 2354 # ln -s powerpc machine 2355 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 2356 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 2357 2358Native builds *don't* work due to incompatibilities between native 2359and U-Boot include files. 2360 2361Booting assumes that (the first part of) the image booted is a 2362stage-2 loader which in turn loads and then invokes the kernel 2363proper. Loader sources will eventually appear in the NetBSD source 2364tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 2365meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for 2366details. 2367 2368 2369Implementation Internals: 2370========================= 2371 2372The following is not intended to be a complete description of every 2373implementation detail. However, it should help to understand the 2374inner workings of U-Boot and make it easier to port it to custom 2375hardware. 2376 2377 2378Initial Stack, Global Data: 2379--------------------------- 2380 2381The implementation of U-Boot is complicated by the fact that U-Boot 2382starts running out of ROM (flash memory), usually without access to 2383system RAM (because the memory controller is not initialized yet). 2384This means that we don't have writable Data or BSS segments, and BSS 2385is not initialized as zero. To be able to get a C environment working 2386at all, we have to allocate at least a minimal stack. Implementation 2387options for this are defined and restricted by the CPU used: Some CPU 2388models provide on-chip memory (like the IMMR area on MPC8xx and 2389MPC826x processors), on others (parts of) the data cache can be 2390locked as (mis-) used as memory, etc. 2391 2392It is essential to remember this, since it has some impact on the C 2393code for the initialization procedures: 2394 2395* Initialized global data (data segment) is read-only. Do not attempt 2396 to write it. 2397 2398* Do not use any unitialized global data (or implicitely initialized 2399 as zero data - BSS segment) at all - this is undefined, initiali- 2400 zation is performed later (when relocationg to RAM). 2401 2402* Stack space is very limited. Avoid big data buffers or things like 2403 that. 2404 2405Having only the stack as writable memory limits means we cannot use 2406normal global data to share information beween the code. But it 2407turned out that the implementation of U-Boot can be greatly 2408simplified by making a global data structure (gd_t) available to all 2409functions. We could pass a pointer to this data as argument to _all_ 2410functions, but this would bloat the code. Instead we use a feature of 2411the GCC compiler (Global Register Variables) to share the data: we 2412place a pointer (gd) to the global data into a register which we 2413reserve for this purpose. 2414 2415When chosing a register for such a purpose we are restricted by the 2416relevant (E)ABI specifications for the current architecture, and by 2417GCC's implementation. 2418 2419For PowerPC, the following registers have specific use: 2420 R1: stack pointer 2421 R2: TOC pointer 2422 R3-R4: parameter passing and return values 2423 R5-R10: parameter passing 2424 R13: small data area pointer 2425 R30: GOT pointer 2426 R31: frame pointer 2427 2428 (U-Boot also uses R14 as internal GOT pointer.) 2429 2430 ==> U-Boot will use R29 to hold a pointer to the global data 2431 2432 Note: on PPC, we could use a static initializer (since the 2433 address of the global data structure is known at compile time), 2434 but it turned out that reserving a register results in somewhat 2435 smaller code - although the code savings are not that big (on 2436 average for all boards 752 bytes for the whole U-Boot image, 2437 624 text + 127 data). 2438 2439On ARM, the following registers are used: 2440 2441 R0: function argument word/integer result 2442 R1-R3: function argument word 2443 R9: GOT pointer 2444 R10: stack limit (used only if stack checking if enabled) 2445 R11: argument (frame) pointer 2446 R12: temporary workspace 2447 R13: stack pointer 2448 R14: link register 2449 R15: program counter 2450 2451 ==> U-Boot will use R8 to hold a pointer to the global data 2452 2453 2454 2455Memory Management: 2456------------------ 2457 2458U-Boot runs in system state and uses physical addresses, i.e. the 2459MMU is not used either for address mapping nor for memory protection. 2460 2461The available memory is mapped to fixed addresses using the memory 2462controller. In this process, a contiguous block is formed for each 2463memory type (Flash, SDRAM, SRAM), even when it consists of several 2464physical memory banks. 2465 2466U-Boot is installed in the first 128 kB of the first Flash bank (on 2467TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 2468booting and sizing and initializing DRAM, the code relocates itself 2469to the upper end of DRAM. Immediately below the U-Boot code some 2470memory is reserved for use by malloc() [see CFG_MALLOC_LEN 2471configuration setting]. Below that, a structure with global Board 2472Info data is placed, followed by the stack (growing downward). 2473 2474Additionally, some exception handler code is copied to the low 8 kB 2475of DRAM (0x00000000 ... 0x00001FFF). 2476 2477So a typical memory configuration with 16 MB of DRAM could look like 2478this: 2479 2480 0x0000 0000 Exception Vector code 2481 : 2482 0x0000 1FFF 2483 0x0000 2000 Free for Application Use 2484 : 2485 : 2486 2487 : 2488 : 2489 0x00FB FF20 Monitor Stack (Growing downward) 2490 0x00FB FFAC Board Info Data and permanent copy of global data 2491 0x00FC 0000 Malloc Arena 2492 : 2493 0x00FD FFFF 2494 0x00FE 0000 RAM Copy of Monitor Code 2495 ... eventually: LCD or video framebuffer 2496 ... eventually: pRAM (Protected RAM - unchanged by reset) 2497 0x00FF FFFF [End of RAM] 2498 2499 2500System Initialization: 2501---------------------- 2502 2503In the reset configuration, U-Boot starts at the reset entry point 2504(on most PowerPC systens at address 0x00000100). Because of the reset 2505configuration for CS0# this is a mirror of the onboard Flash memory. 2506To be able to re-map memory U-Boot then jumps to it's link address. 2507To be able to implement the initialization code in C, a (small!) 2508initial stack is set up in the internal Dual Ported RAM (in case CPUs 2509which provide such a feature like MPC8xx or MPC8260), or in a locked 2510part of the data cache. After that, U-Boot initializes the CPU core, 2511the caches and the SIU. 2512 2513Next, all (potentially) available memory banks are mapped using a 2514preliminary mapping. For example, we put them on 512 MB boundaries 2515(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 2516on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 2517programmed for SDRAM access. Using the temporary configuration, a 2518simple memory test is run that determines the size of the SDRAM 2519banks. 2520 2521When there is more than one SDRAM bank, and the banks are of 2522different size, the larger is mapped first. For equal size, the first 2523bank (CS2#) is mapped first. The first mapping is always for address 25240x00000000, with any additional banks following immediately to create 2525contiguous memory starting from 0. 2526 2527Then, the monitor installs itself at the upper end of the SDRAM area 2528and allocates memory for use by malloc() and for the global Board 2529Info data; also, the exception vector code is copied to the low RAM 2530pages, and the final stack is set up. 2531 2532Only after this relocation will you have a "normal" C environment; 2533until that you are restricted in several ways, mostly because you are 2534running from ROM, and because the code will have to be relocated to a 2535new address in RAM. 2536 2537 2538U-Boot Porting Guide: 2539---------------------- 2540 2541[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 2542list, Octover 2002] 2543 2544 2545int main (int argc, char *argv[]) 2546{ 2547 sighandler_t no_more_time; 2548 2549 signal (SIGALRM, no_more_time); 2550 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 2551 2552 if (available_money > available_manpower) { 2553 pay consultant to port U-Boot; 2554 return 0; 2555 } 2556 2557 Download latest U-Boot source; 2558 2559 if (clueless) { 2560 email ("Hi, I am new to U-Boot, how do I get started?"); 2561 } 2562 2563 while (learning) { 2564 Read the README file in the top level directory; 2565 Read http://www.denx.de/re/DPLG.html 2566 Read the source, Luke; 2567 } 2568 2569 if (available_money > toLocalCurrency ($2500)) { 2570 Buy a BDI2000; 2571 } else { 2572 Add a lot of aggravation and time; 2573 } 2574 2575 Create your own board support subdirectory; 2576 2577 while (!running) { 2578 do { 2579 Add / modify source code; 2580 } until (compiles); 2581 Debug; 2582 if (clueless) 2583 email ("Hi, I am having problems..."); 2584 } 2585 Send patch file to Wolfgang; 2586 2587 return 0; 2588} 2589 2590void no_more_time (int sig) 2591{ 2592 hire_a_guru(); 2593} 2594 2595 2596 2597Coding Standards: 2598----------------- 2599 2600All contributions to U-Boot should conform to the Linux kernel 2601coding style; see the file "Documentation/CodingStyle" in your Linux 2602kernel source directory. 2603 2604Please note that U-Boot is implemented in C (and to some small parts 2605in Assembler); no C++ is used, so please do not use C++ style 2606comments (//) in your code. 2607 2608Submissions which do not conform to the standards may be returned 2609with a request to reformat the changes. 2610 2611 2612Submitting Patches: 2613------------------- 2614 2615Since the number of patches for U-Boot is growing, we need to 2616establish some rules. Submissions which do not conform to these rules 2617may be rejected, even when they contain important and valuable stuff. 2618 2619 2620When you send a patch, please include the following information with 2621it: 2622 2623* For bug fixes: a description of the bug and how your patch fixes 2624 this bug. Please try to include a way of demonstrating that the 2625 patch actually fixes something. 2626 2627* For new features: a description of the feature and your 2628 implementation. 2629 2630* A CHANGELOG entry as plaintext (separate from the patch) 2631 2632* For major contributions, your entry to the CREDITS file 2633 2634* When you add support for a new board, don't forget to add this 2635 board to the MAKEALL script, too. 2636 2637* If your patch adds new configuration options, don't forget to 2638 document these in the README file. 2639 2640* The patch itself. If you are accessing the CVS repository use "cvs 2641 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 2642 version of diff does not support these options, then get the latest 2643 version of GNU diff. 2644 2645 We accept patches as plain text, MIME attachments or as uuencoded 2646 gzipped text. 2647 2648Notes: 2649 2650* Before sending the patch, run the MAKEALL script on your patched 2651 source tree and make sure that no errors or warnings are reported 2652 for any of the boards. 2653 2654* Keep your modifications to the necessary minimum: A patch 2655 containing several unrelated changes or arbitrary reformats will be 2656 returned with a request to re-formatting / split it. 2657 2658* If you modify existing code, make sure that your new code does not 2659 add to the memory footprint of the code ;-) Small is beautiful! 2660 When adding new features, these should compile conditionally only 2661 (using #ifdef), and the resulting code with the new feature 2662 disabled must not need more memory than the old code without your 2663 modification. 2664