1# 2# (C) Copyright 2000 - 2005 3# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4# 5# See file CREDITS for list of people who contributed to this 6# project. 7# 8# This program is free software; you can redistribute it and/or 9# modify it under the terms of the GNU General Public License as 10# published by the Free Software Foundation; either version 2 of 11# the License, or (at your option) any later version. 12# 13# This program is distributed in the hope that it will be useful, 14# but WITHOUT ANY WARRANTY; without even the implied warranty of 15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16# GNU General Public License for more details. 17# 18# You should have received a copy of the GNU General Public License 19# along with this program; if not, write to the Free Software 20# Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21# MA 02111-1307 USA 22# 23 24Summary: 25======== 26 27This directory contains the source code for U-Boot, a boot loader for 28Embedded boards based on PowerPC, ARM, MIPS and several other 29processors, which can be installed in a boot ROM and used to 30initialize and test the hardware or to download and run application 31code. 32 33The development of U-Boot is closely related to Linux: some parts of 34the source code originate in the Linux source tree, we have some 35header files in common, and special provision has been made to 36support booting of Linux images. 37 38Some attention has been paid to make this software easily 39configurable and extendable. For instance, all monitor commands are 40implemented with the same call interface, so that it's very easy to 41add new commands. Also, instead of permanently adding rarely used 42code (for instance hardware test utilities) to the monitor, you can 43load and run it dynamically. 44 45 46Status: 47======= 48 49In general, all boards for which a configuration option exists in the 50Makefile have been tested to some extent and can be considered 51"working". In fact, many of them are used in production systems. 52 53In case of problems see the CHANGELOG and CREDITS files to find out 54who contributed the specific port. 55 56 57Where to get help: 58================== 59 60In case you have questions about, problems with or contributions for 61U-Boot you should send a message to the U-Boot mailing list at 62<u-boot-users@lists.sourceforge.net>. There is also an archive of 63previous traffic on the mailing list - please search the archive 64before asking FAQ's. Please see 65http://lists.sourceforge.net/lists/listinfo/u-boot-users/ 66 67 68Where we come from: 69=================== 70 71- start from 8xxrom sources 72- create PPCBoot project (http://sourceforge.net/projects/ppcboot) 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- create ARMBoot project (http://sourceforge.net/projects/armboot) 82- add other CPU families (starting with ARM) 83- create U-Boot project (http://sourceforge.net/projects/u-boot) 84 85 86Names and Spelling: 87=================== 88 89The "official" name of this project is "Das U-Boot". The spelling 90"U-Boot" shall be used in all written text (documentation, comments 91in source files etc.). Example: 92 93 This is the README file for the U-Boot project. 94 95File names etc. shall be based on the string "u-boot". Examples: 96 97 include/asm-ppc/u-boot.h 98 99 #include <asm/u-boot.h> 100 101Variable names, preprocessor constants etc. shall be either based on 102the string "u_boot" or on "U_BOOT". Example: 103 104 U_BOOT_VERSION u_boot_logo 105 IH_OS_U_BOOT u_boot_hush_start 106 107 108Versioning: 109=========== 110 111U-Boot uses a 3 level version number containing a version, a 112sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2", 113sub-version "34", and patchlevel "4". 114 115The patchlevel is used to indicate certain stages of development 116between released versions, i. e. officially released versions of 117U-Boot will always have a patchlevel of "0". 118 119 120Directory Hierarchy: 121==================== 122 123- board Board dependent files 124- common Misc architecture independent functions 125- cpu CPU specific files 126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs 127 - arm720t Files specific to ARM 720 CPUs 128 - arm920t Files specific to ARM 920 CPUs 129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU 130 - imx Files specific to Freescale MC9328 i.MX CPUs 131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs 132 - arm925t Files specific to ARM 925 CPUs 133 - arm926ejs Files specific to ARM 926 CPUs 134 - arm1136 Files specific to ARM 1136 CPUs 135 - at32ap Files specific to Atmel AVR32 AP CPUs 136 - i386 Files specific to i386 CPUs 137 - ixp Files specific to Intel XScale IXP CPUs 138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs 139 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs 140 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs 141 - mips Files specific to MIPS CPUs 142 - mpc5xx Files specific to Freescale MPC5xx CPUs 143 - mpc5xxx Files specific to Freescale MPC5xxx CPUs 144 - mpc8xx Files specific to Freescale MPC8xx CPUs 145 - mpc8220 Files specific to Freescale MPC8220 CPUs 146 - mpc824x Files specific to Freescale MPC824x CPUs 147 - mpc8260 Files specific to Freescale MPC8260 CPUs 148 - mpc85xx Files specific to Freescale MPC85xx CPUs 149 - nios Files specific to Altera NIOS CPUs 150 - nios2 Files specific to Altera Nios-II CPUs 151 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs 152 - pxa Files specific to Intel XScale PXA CPUs 153 - s3c44b0 Files specific to Samsung S3C44B0 CPUs 154 - sa1100 Files specific to Intel StrongARM SA1100 CPUs 155- disk Code for disk drive partition handling 156- doc Documentation (don't expect too much) 157- drivers Commonly used device drivers 158- dtt Digital Thermometer and Thermostat drivers 159- examples Example code for standalone applications, etc. 160- include Header Files 161- lib_arm Files generic to ARM architecture 162- lib_avr32 Files generic to AVR32 architecture 163- lib_generic Files generic to all architectures 164- lib_i386 Files generic to i386 architecture 165- lib_m68k Files generic to m68k architecture 166- lib_mips Files generic to MIPS architecture 167- lib_nios Files generic to NIOS architecture 168- lib_ppc Files generic to PowerPC architecture 169- libfdt Library files to support flattened device trees 170- net Networking code 171- post Power On Self Test 172- rtc Real Time Clock drivers 173- tools Tools to build S-Record or U-Boot images, etc. 174 175Software Configuration: 176======================= 177 178Configuration is usually done using C preprocessor defines; the 179rationale behind that is to avoid dead code whenever possible. 180 181There are two classes of configuration variables: 182 183* Configuration _OPTIONS_: 184 These are selectable by the user and have names beginning with 185 "CONFIG_". 186 187* Configuration _SETTINGS_: 188 These depend on the hardware etc. and should not be meddled with if 189 you don't know what you're doing; they have names beginning with 190 "CFG_". 191 192Later we will add a configuration tool - probably similar to or even 193identical to what's used for the Linux kernel. Right now, we have to 194do the configuration by hand, which means creating some symbolic 195links and editing some configuration files. We use the TQM8xxL boards 196as an example here. 197 198 199Selection of Processor Architecture and Board Type: 200--------------------------------------------------- 201 202For all supported boards there are ready-to-use default 203configurations available; just type "make <board_name>_config". 204 205Example: For a TQM823L module type: 206 207 cd u-boot 208 make TQM823L_config 209 210For the Cogent platform, you need to specify the cpu type as well; 211e.g. "make cogent_mpc8xx_config". And also configure the cogent 212directory according to the instructions in cogent/README. 213 214 215Configuration Options: 216---------------------- 217 218Configuration depends on the combination of board and CPU type; all 219such information is kept in a configuration file 220"include/configs/<board_name>.h". 221 222Example: For a TQM823L module, all configuration settings are in 223"include/configs/TQM823L.h". 224 225 226Many of the options are named exactly as the corresponding Linux 227kernel configuration options. The intention is to make it easier to 228build a config tool - later. 229 230 231The following options need to be configured: 232 233- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX. 234 235- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS. 236 237- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined) 238 Define exactly one, e.g. CONFIG_ATSTK1002 239 240- CPU Module Type: (if CONFIG_COGENT is defined) 241 Define exactly one of 242 CONFIG_CMA286_60_OLD 243--- FIXME --- not tested yet: 244 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, 245 CONFIG_CMA287_23, CONFIG_CMA287_50 246 247- Motherboard Type: (if CONFIG_COGENT is defined) 248 Define exactly one of 249 CONFIG_CMA101, CONFIG_CMA102 250 251- Motherboard I/O Modules: (if CONFIG_COGENT is defined) 252 Define one or more of 253 CONFIG_CMA302 254 255- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) 256 Define one or more of 257 CONFIG_LCD_HEARTBEAT - update a character position on 258 the lcd display every second with 259 a "rotator" |\-/|\-/ 260 261- Board flavour: (if CONFIG_MPC8260ADS is defined) 262 CONFIG_ADSTYPE 263 Possible values are: 264 CFG_8260ADS - original MPC8260ADS 265 CFG_8266ADS - MPC8266ADS 266 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR 267 CFG_8272ADS - MPC8272ADS 268 269- MPC824X Family Member (if CONFIG_MPC824X is defined) 270 Define exactly one of 271 CONFIG_MPC8240, CONFIG_MPC8245 272 273- 8xx CPU Options: (if using an MPC8xx cpu) 274 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if 275 get_gclk_freq() cannot work 276 e.g. if there is no 32KHz 277 reference PIT/RTC clock 278 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK 279 or XTAL/EXTAL) 280 281- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU): 282 CFG_8xx_CPUCLK_MIN 283 CFG_8xx_CPUCLK_MAX 284 CONFIG_8xx_CPUCLK_DEFAULT 285 See doc/README.MPC866 286 287 CFG_MEASURE_CPUCLK 288 289 Define this to measure the actual CPU clock instead 290 of relying on the correctness of the configured 291 values. Mostly useful for board bringup to make sure 292 the PLL is locked at the intended frequency. Note 293 that this requires a (stable) reference clock (32 kHz 294 RTC clock or CFG_8XX_XIN) 295 296- Intel Monahans options: 297 CFG_MONAHANS_RUN_MODE_OSC_RATIO 298 299 Defines the Monahans run mode to oscillator 300 ratio. Valid values are 8, 16, 24, 31. The core 301 frequency is this value multiplied by 13 MHz. 302 303 CFG_MONAHANS_TURBO_RUN_MODE_RATIO 304 305 Defines the Monahans turbo mode to oscillator 306 ratio. Valid values are 1 (default if undefined) and 307 2. The core frequency as calculated above is multiplied 308 by this value. 309 310- Linux Kernel Interface: 311 CONFIG_CLOCKS_IN_MHZ 312 313 U-Boot stores all clock information in Hz 314 internally. For binary compatibility with older Linux 315 kernels (which expect the clocks passed in the 316 bd_info data to be in MHz) the environment variable 317 "clocks_in_mhz" can be defined so that U-Boot 318 converts clock data to MHZ before passing it to the 319 Linux kernel. 320 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of 321 "clocks_in_mhz=1" is automatically included in the 322 default environment. 323 324 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 325 326 When transfering memsize parameter to linux, some versions 327 expect it to be in bytes, others in MB. 328 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 329 330 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE 331 332 New kernel versions are expecting firmware settings to be 333 passed using flattened device trees (based on open firmware 334 concepts). 335 336 CONFIG_OF_LIBFDT 337 * New libfdt-based support 338 * Adds the "fdt" command 339 * The bootm command automatically updates the fdt 340 341 CONFIG_OF_FLAT_TREE 342 * Deprecated, see CONFIG_OF_LIBFDT 343 * Original ft_build.c-based support 344 * Automatically modifies the dft as part of the bootm command 345 * The environment variable "disable_of", when set, 346 disables this functionality. 347 348 OF_CPU - The proper name of the cpus node. 349 OF_SOC - The proper name of the soc node. 350 OF_TBCLK - The timebase frequency. 351 OF_STDOUT_PATH - The path to the console device 352 353 boards with QUICC Engines require OF_QE to set UCC mac addresses 354 355 CONFIG_OF_HAS_BD_T 356 357 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command 358 * CONFIG_OF_FLAT_TREE - The resulting flat device tree 359 will have a copy of the bd_t. Space should be 360 pre-allocated in the dts for the bd_t. 361 362 CONFIG_OF_HAS_UBOOT_ENV 363 364 * CONFIG_OF_LIBFDT - enables the "fdt env" command 365 * CONFIG_OF_FLAT_TREE - The resulting flat device tree 366 will have a copy of u-boot's environment variables 367 368 CONFIG_OF_BOARD_SETUP 369 370 Board code has addition modification that it wants to make 371 to the flat device tree before handing it off to the kernel 372 373 CONFIG_OF_BOOT_CPU 374 375 This define fills in the correct boot cpu in the boot 376 param header, the default value is zero if undefined. 377 378- Serial Ports: 379 CFG_PL010_SERIAL 380 381 Define this if you want support for Amba PrimeCell PL010 UARTs. 382 383 CFG_PL011_SERIAL 384 385 Define this if you want support for Amba PrimeCell PL011 UARTs. 386 387 CONFIG_PL011_CLOCK 388 389 If you have Amba PrimeCell PL011 UARTs, set this variable to 390 the clock speed of the UARTs. 391 392 CONFIG_PL01x_PORTS 393 394 If you have Amba PrimeCell PL010 or PL011 UARTs on your board, 395 define this to a list of base addresses for each (supported) 396 port. See e.g. include/configs/versatile.h 397 398 399- Console Interface: 400 Depending on board, define exactly one serial port 401 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, 402 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial 403 console by defining CONFIG_8xx_CONS_NONE 404 405 Note: if CONFIG_8xx_CONS_NONE is defined, the serial 406 port routines must be defined elsewhere 407 (i.e. serial_init(), serial_getc(), ...) 408 409 CONFIG_CFB_CONSOLE 410 Enables console device for a color framebuffer. Needs following 411 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) 412 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation 413 (default big endian) 414 VIDEO_HW_RECTFILL graphic chip supports 415 rectangle fill 416 (cf. smiLynxEM) 417 VIDEO_HW_BITBLT graphic chip supports 418 bit-blit (cf. smiLynxEM) 419 VIDEO_VISIBLE_COLS visible pixel columns 420 (cols=pitch) 421 VIDEO_VISIBLE_ROWS visible pixel rows 422 VIDEO_PIXEL_SIZE bytes per pixel 423 VIDEO_DATA_FORMAT graphic data format 424 (0-5, cf. cfb_console.c) 425 VIDEO_FB_ADRS framebuffer address 426 VIDEO_KBD_INIT_FCT keyboard int fct 427 (i.e. i8042_kbd_init()) 428 VIDEO_TSTC_FCT test char fct 429 (i.e. i8042_tstc) 430 VIDEO_GETC_FCT get char fct 431 (i.e. i8042_getc) 432 CONFIG_CONSOLE_CURSOR cursor drawing on/off 433 (requires blink timer 434 cf. i8042.c) 435 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) 436 CONFIG_CONSOLE_TIME display time/date info in 437 upper right corner 438 (requires CONFIG_CMD_DATE) 439 CONFIG_VIDEO_LOGO display Linux logo in 440 upper left corner 441 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of 442 linux_logo.h for logo. 443 Requires CONFIG_VIDEO_LOGO 444 CONFIG_CONSOLE_EXTRA_INFO 445 addional board info beside 446 the logo 447 448 When CONFIG_CFB_CONSOLE is defined, video console is 449 default i/o. Serial console can be forced with 450 environment 'console=serial'. 451 452 When CONFIG_SILENT_CONSOLE is defined, all console 453 messages (by U-Boot and Linux!) can be silenced with 454 the "silent" environment variable. See 455 doc/README.silent for more information. 456 457- Console Baudrate: 458 CONFIG_BAUDRATE - in bps 459 Select one of the baudrates listed in 460 CFG_BAUDRATE_TABLE, see below. 461 CFG_BRGCLK_PRESCALE, baudrate prescale 462 463- Interrupt driven serial port input: 464 CONFIG_SERIAL_SOFTWARE_FIFO 465 466 PPC405GP only. 467 Use an interrupt handler for receiving data on the 468 serial port. It also enables using hardware handshake 469 (RTS/CTS) and UART's built-in FIFO. Set the number of 470 bytes the interrupt driven input buffer should have. 471 472 Leave undefined to disable this feature, including 473 disable the buffer and hardware handshake. 474 475- Console UART Number: 476 CONFIG_UART1_CONSOLE 477 478 AMCC PPC4xx only. 479 If defined internal UART1 (and not UART0) is used 480 as default U-Boot console. 481 482- Boot Delay: CONFIG_BOOTDELAY - in seconds 483 Delay before automatically booting the default image; 484 set to -1 to disable autoboot. 485 486 See doc/README.autoboot for these options that 487 work with CONFIG_BOOTDELAY. None are required. 488 CONFIG_BOOT_RETRY_TIME 489 CONFIG_BOOT_RETRY_MIN 490 CONFIG_AUTOBOOT_KEYED 491 CONFIG_AUTOBOOT_PROMPT 492 CONFIG_AUTOBOOT_DELAY_STR 493 CONFIG_AUTOBOOT_STOP_STR 494 CONFIG_AUTOBOOT_DELAY_STR2 495 CONFIG_AUTOBOOT_STOP_STR2 496 CONFIG_ZERO_BOOTDELAY_CHECK 497 CONFIG_RESET_TO_RETRY 498 499- Autoboot Command: 500 CONFIG_BOOTCOMMAND 501 Only needed when CONFIG_BOOTDELAY is enabled; 502 define a command string that is automatically executed 503 when no character is read on the console interface 504 within "Boot Delay" after reset. 505 506 CONFIG_BOOTARGS 507 This can be used to pass arguments to the bootm 508 command. The value of CONFIG_BOOTARGS goes into the 509 environment value "bootargs". 510 511 CONFIG_RAMBOOT and CONFIG_NFSBOOT 512 The value of these goes into the environment as 513 "ramboot" and "nfsboot" respectively, and can be used 514 as a convenience, when switching between booting from 515 ram and nfs. 516 517- Pre-Boot Commands: 518 CONFIG_PREBOOT 519 520 When this option is #defined, the existence of the 521 environment variable "preboot" will be checked 522 immediately before starting the CONFIG_BOOTDELAY 523 countdown and/or running the auto-boot command resp. 524 entering interactive mode. 525 526 This feature is especially useful when "preboot" is 527 automatically generated or modified. For an example 528 see the LWMON board specific code: here "preboot" is 529 modified when the user holds down a certain 530 combination of keys on the (special) keyboard when 531 booting the systems 532 533- Serial Download Echo Mode: 534 CONFIG_LOADS_ECHO 535 If defined to 1, all characters received during a 536 serial download (using the "loads" command) are 537 echoed back. This might be needed by some terminal 538 emulations (like "cu"), but may as well just take 539 time on others. This setting #define's the initial 540 value of the "loads_echo" environment variable. 541 542- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined) 543 CONFIG_KGDB_BAUDRATE 544 Select one of the baudrates listed in 545 CFG_BAUDRATE_TABLE, see below. 546 547- Monitor Functions: 548 Monitor commands can be included or excluded 549 from the build by using the #include files 550 "config_cmd_all.h" and #undef'ing unwanted 551 commands, or using "config_cmd_default.h" 552 and augmenting with additional #define's 553 for wanted commands. 554 555 The default command configuration includes all commands 556 except those marked below with a "*". 557 558 CONFIG_CMD_ASKENV * ask for env variable 559 CONFIG_CMD_AUTOSCRIPT Autoscript Support 560 CONFIG_CMD_BDI bdinfo 561 CONFIG_CMD_BEDBUG * Include BedBug Debugger 562 CONFIG_CMD_BMP * BMP support 563 CONFIG_CMD_BSP * Board specific commands 564 CONFIG_CMD_BOOTD bootd 565 CONFIG_CMD_CACHE * icache, dcache 566 CONFIG_CMD_CONSOLE coninfo 567 CONFIG_CMD_DATE * support for RTC, date/time... 568 CONFIG_CMD_DHCP * DHCP support 569 CONFIG_CMD_DIAG * Diagnostics 570 CONFIG_CMD_DOC * Disk-On-Chip Support 571 CONFIG_CMD_DTT * Digital Therm and Thermostat 572 CONFIG_CMD_ECHO echo arguments 573 CONFIG_CMD_EEPROM * EEPROM read/write support 574 CONFIG_CMD_ELF * bootelf, bootvx 575 CONFIG_CMD_ENV saveenv 576 CONFIG_CMD_FDC * Floppy Disk Support 577 CONFIG_CMD_FAT * FAT partition support 578 CONFIG_CMD_FDOS * Dos diskette Support 579 CONFIG_CMD_FLASH flinfo, erase, protect 580 CONFIG_CMD_FPGA FPGA device initialization support 581 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control 582 CONFIG_CMD_I2C * I2C serial bus support 583 CONFIG_CMD_IDE * IDE harddisk support 584 CONFIG_CMD_IMI iminfo 585 CONFIG_CMD_IMLS List all found images 586 CONFIG_CMD_IMMAP * IMMR dump support 587 CONFIG_CMD_IRQ * irqinfo 588 CONFIG_CMD_ITEST Integer/string test of 2 values 589 CONFIG_CMD_JFFS2 * JFFS2 Support 590 CONFIG_CMD_KGDB * kgdb 591 CONFIG_CMD_LOADB loadb 592 CONFIG_CMD_LOADS loads 593 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, 594 loop, loopw, mtest 595 CONFIG_CMD_MISC Misc functions like sleep etc 596 CONFIG_CMD_MMC * MMC memory mapped support 597 CONFIG_CMD_MII * MII utility commands 598 CONFIG_CMD_NAND * NAND support 599 CONFIG_CMD_NET bootp, tftpboot, rarpboot 600 CONFIG_CMD_PCI * pciinfo 601 CONFIG_CMD_PCMCIA * PCMCIA support 602 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network 603 host 604 CONFIG_CMD_PORTIO * Port I/O 605 CONFIG_CMD_REGINFO * Register dump 606 CONFIG_CMD_RUN run command in env variable 607 CONFIG_CMD_SAVES * save S record dump 608 CONFIG_CMD_SCSI * SCSI Support 609 CONFIG_CMD_SDRAM * print SDRAM configuration information 610 (requires CONFIG_CMD_I2C) 611 CONFIG_CMD_SETGETDCR Support for DCR Register access 612 (4xx only) 613 CONFIG_CMD_SPI * SPI serial bus support 614 CONFIG_CMD_USB * USB support 615 CONFIG_CMD_VFD * VFD support (TRAB) 616 CONFIG_CMD_BSP * Board SPecific functions 617 CONFIG_CMD_CDP * Cisco Discover Protocol support 618 CONFIG_CMD_FSL * Microblaze FSL support 619 620 621 EXAMPLE: If you want all functions except of network 622 support you can write: 623 624 #include "config_cmd_all.h" 625 #undef CONFIG_CMD_NET 626 627 Other Commands: 628 fdt (flattened device tree) command: CONFIG_OF_LIBFDT 629 630 Note: Don't enable the "icache" and "dcache" commands 631 (configuration option CONFIG_CMD_CACHE) unless you know 632 what you (and your U-Boot users) are doing. Data 633 cache cannot be enabled on systems like the 8xx or 634 8260 (where accesses to the IMMR region must be 635 uncached), and it cannot be disabled on all other 636 systems where we (mis-) use the data cache to hold an 637 initial stack and some data. 638 639 640 XXX - this list needs to get updated! 641 642- Watchdog: 643 CONFIG_WATCHDOG 644 If this variable is defined, it enables watchdog 645 support. There must be support in the platform specific 646 code for a watchdog. For the 8xx and 8260 CPUs, the 647 SIU Watchdog feature is enabled in the SYPCR 648 register. 649 650- U-Boot Version: 651 CONFIG_VERSION_VARIABLE 652 If this variable is defined, an environment variable 653 named "ver" is created by U-Boot showing the U-Boot 654 version as printed by the "version" command. 655 This variable is readonly. 656 657- Real-Time Clock: 658 659 When CONFIG_CMD_DATE is selected, the type of the RTC 660 has to be selected, too. Define exactly one of the 661 following options: 662 663 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx 664 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 665 CONFIG_RTC_MC146818 - use MC146818 RTC 666 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 667 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 668 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 669 CONFIG_RTC_DS164x - use Dallas DS164x RTC 670 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 671 672 Note that if the RTC uses I2C, then the I2C interface 673 must also be configured. See I2C Support, below. 674 675- Timestamp Support: 676 677 When CONFIG_TIMESTAMP is selected, the timestamp 678 (date and time) of an image is printed by image 679 commands like bootm or iminfo. This option is 680 automatically enabled when you select CONFIG_CMD_DATE . 681 682- Partition Support: 683 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION 684 and/or CONFIG_ISO_PARTITION 685 686 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or 687 CONFIG_CMD_SCSI) you must configure support for at least 688 one partition type as well. 689 690- IDE Reset method: 691 CONFIG_IDE_RESET_ROUTINE - this is defined in several 692 board configurations files but used nowhere! 693 694 CONFIG_IDE_RESET - is this is defined, IDE Reset will 695 be performed by calling the function 696 ide_set_reset(int reset) 697 which has to be defined in a board specific file 698 699- ATAPI Support: 700 CONFIG_ATAPI 701 702 Set this to enable ATAPI support. 703 704- LBA48 Support 705 CONFIG_LBA48 706 707 Set this to enable support for disks larger than 137GB 708 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL 709 Whithout these , LBA48 support uses 32bit variables and will 'only' 710 support disks up to 2.1TB. 711 712 CFG_64BIT_LBA: 713 When enabled, makes the IDE subsystem use 64bit sector addresses. 714 Default is 32bit. 715 716- SCSI Support: 717 At the moment only there is only support for the 718 SYM53C8XX SCSI controller; define 719 CONFIG_SCSI_SYM53C8XX to enable it. 720 721 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and 722 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * 723 CFG_SCSI_MAX_LUN] can be adjusted to define the 724 maximum numbers of LUNs, SCSI ID's and target 725 devices. 726 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) 727 728- NETWORK Support (PCI): 729 CONFIG_E1000 730 Support for Intel 8254x gigabit chips. 731 732 CONFIG_EEPRO100 733 Support for Intel 82557/82559/82559ER chips. 734 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom 735 write routine for first time initialisation. 736 737 CONFIG_TULIP 738 Support for Digital 2114x chips. 739 Optional CONFIG_TULIP_SELECT_MEDIA for board specific 740 modem chip initialisation (KS8761/QS6611). 741 742 CONFIG_NATSEMI 743 Support for National dp83815 chips. 744 745 CONFIG_NS8382X 746 Support for National dp8382[01] gigabit chips. 747 748- NETWORK Support (other): 749 750 CONFIG_DRIVER_LAN91C96 751 Support for SMSC's LAN91C96 chips. 752 753 CONFIG_LAN91C96_BASE 754 Define this to hold the physical address 755 of the LAN91C96's I/O space 756 757 CONFIG_LAN91C96_USE_32_BIT 758 Define this to enable 32 bit addressing 759 760 CONFIG_DRIVER_SMC91111 761 Support for SMSC's LAN91C111 chip 762 763 CONFIG_SMC91111_BASE 764 Define this to hold the physical address 765 of the device (I/O space) 766 767 CONFIG_SMC_USE_32_BIT 768 Define this if data bus is 32 bits 769 770 CONFIG_SMC_USE_IOFUNCS 771 Define this to use i/o functions instead of macros 772 (some hardware wont work with macros) 773 774- USB Support: 775 At the moment only the UHCI host controller is 776 supported (PIP405, MIP405, MPC5200); define 777 CONFIG_USB_UHCI to enable it. 778 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 779 and define CONFIG_USB_STORAGE to enable the USB 780 storage devices. 781 Note: 782 Supported are USB Keyboards and USB Floppy drives 783 (TEAC FD-05PUB). 784 MPC5200 USB requires additional defines: 785 CONFIG_USB_CLOCK 786 for 528 MHz Clock: 0x0001bbbb 787 CONFIG_USB_CONFIG 788 for differential drivers: 0x00001000 789 for single ended drivers: 0x00005000 790 CFG_USB_EVENT_POLL 791 May be defined to allow interrupt polling 792 instead of using asynchronous interrupts 793 794- USB Device: 795 Define the below if you wish to use the USB console. 796 Once firmware is rebuilt from a serial console issue the 797 command "setenv stdin usbtty; setenv stdout usbtty" and 798 attach your usb cable. The Unix command "dmesg" should print 799 it has found a new device. The environment variable usbtty 800 can be set to gserial or cdc_acm to enable your device to 801 appear to a USB host as a Linux gserial device or a 802 Common Device Class Abstract Control Model serial device. 803 If you select usbtty = gserial you should be able to enumerate 804 a Linux host by 805 # modprobe usbserial vendor=0xVendorID product=0xProductID 806 else if using cdc_acm, simply setting the environment 807 variable usbtty to be cdc_acm should suffice. The following 808 might be defined in YourBoardName.h 809 810 CONFIG_USB_DEVICE 811 Define this to build a UDC device 812 813 CONFIG_USB_TTY 814 Define this to have a tty type of device available to 815 talk to the UDC device 816 817 CFG_CONSOLE_IS_IN_ENV 818 Define this if you want stdin, stdout &/or stderr to 819 be set to usbtty. 820 821 mpc8xx: 822 CFG_USB_EXTC_CLK 0xBLAH 823 Derive USB clock from external clock "blah" 824 - CFG_USB_EXTC_CLK 0x02 825 826 CFG_USB_BRG_CLK 0xBLAH 827 Derive USB clock from brgclk 828 - CFG_USB_BRG_CLK 0x04 829 830 If you have a USB-IF assigned VendorID then you may wish to 831 define your own vendor specific values either in BoardName.h 832 or directly in usbd_vendor_info.h. If you don't define 833 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 834 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 835 should pretend to be a Linux device to it's target host. 836 837 CONFIG_USBD_MANUFACTURER 838 Define this string as the name of your company for 839 - CONFIG_USBD_MANUFACTURER "my company" 840 841 CONFIG_USBD_PRODUCT_NAME 842 Define this string as the name of your product 843 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 844 845 CONFIG_USBD_VENDORID 846 Define this as your assigned Vendor ID from the USB 847 Implementors Forum. This *must* be a genuine Vendor ID 848 to avoid polluting the USB namespace. 849 - CONFIG_USBD_VENDORID 0xFFFF 850 851 CONFIG_USBD_PRODUCTID 852 Define this as the unique Product ID 853 for your device 854 - CONFIG_USBD_PRODUCTID 0xFFFF 855 856 857- MMC Support: 858 The MMC controller on the Intel PXA is supported. To 859 enable this define CONFIG_MMC. The MMC can be 860 accessed from the boot prompt by mapping the device 861 to physical memory similar to flash. Command line is 862 enabled with CONFIG_CMD_MMC. The MMC driver also works with 863 the FAT fs. This is enabled with CONFIG_CMD_FAT. 864 865- Journaling Flash filesystem support: 866 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE, 867 CONFIG_JFFS2_NAND_DEV 868 Define these for a default partition on a NAND device 869 870 CFG_JFFS2_FIRST_SECTOR, 871 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS 872 Define these for a default partition on a NOR device 873 874 CFG_JFFS_CUSTOM_PART 875 Define this to create an own partition. You have to provide a 876 function struct part_info* jffs2_part_info(int part_num) 877 878 If you define only one JFFS2 partition you may also want to 879 #define CFG_JFFS_SINGLE_PART 1 880 to disable the command chpart. This is the default when you 881 have not defined a custom partition 882 883- Keyboard Support: 884 CONFIG_ISA_KEYBOARD 885 886 Define this to enable standard (PC-Style) keyboard 887 support 888 889 CONFIG_I8042_KBD 890 Standard PC keyboard driver with US (is default) and 891 GERMAN key layout (switch via environment 'keymap=de') support. 892 Export function i8042_kbd_init, i8042_tstc and i8042_getc 893 for cfb_console. Supports cursor blinking. 894 895- Video support: 896 CONFIG_VIDEO 897 898 Define this to enable video support (for output to 899 video). 900 901 CONFIG_VIDEO_CT69000 902 903 Enable Chips & Technologies 69000 Video chip 904 905 CONFIG_VIDEO_SMI_LYNXEM 906 Enable Silicon Motion SMI 712/710/810 Video chip. The 907 video output is selected via environment 'videoout' 908 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is 909 assumed. 910 911 For the CT69000 and SMI_LYNXEM drivers, videomode is 912 selected via environment 'videomode'. Two diferent ways 913 are possible: 914 - "videomode=num" 'num' is a standard LiLo mode numbers. 915 Following standard modes are supported (* is default): 916 917 Colors 640x480 800x600 1024x768 1152x864 1280x1024 918 -------------+--------------------------------------------- 919 8 bits | 0x301* 0x303 0x305 0x161 0x307 920 15 bits | 0x310 0x313 0x316 0x162 0x319 921 16 bits | 0x311 0x314 0x317 0x163 0x31A 922 24 bits | 0x312 0x315 0x318 ? 0x31B 923 -------------+--------------------------------------------- 924 (i.e. setenv videomode 317; saveenv; reset;) 925 926 - "videomode=bootargs" all the video parameters are parsed 927 from the bootargs. (See drivers/video/videomodes.c) 928 929 930 CONFIG_VIDEO_SED13806 931 Enable Epson SED13806 driver. This driver supports 8bpp 932 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP 933 or CONFIG_VIDEO_SED13806_16BPP 934 935- Keyboard Support: 936 CONFIG_KEYBOARD 937 938 Define this to enable a custom keyboard support. 939 This simply calls drv_keyboard_init() which must be 940 defined in your board-specific files. 941 The only board using this so far is RBC823. 942 943- LCD Support: CONFIG_LCD 944 945 Define this to enable LCD support (for output to LCD 946 display); also select one of the supported displays 947 by defining one of these: 948 949 CONFIG_NEC_NL6448AC33: 950 951 NEC NL6448AC33-18. Active, color, single scan. 952 953 CONFIG_NEC_NL6448BC20 954 955 NEC NL6448BC20-08. 6.5", 640x480. 956 Active, color, single scan. 957 958 CONFIG_NEC_NL6448BC33_54 959 960 NEC NL6448BC33-54. 10.4", 640x480. 961 Active, color, single scan. 962 963 CONFIG_SHARP_16x9 964 965 Sharp 320x240. Active, color, single scan. 966 It isn't 16x9, and I am not sure what it is. 967 968 CONFIG_SHARP_LQ64D341 969 970 Sharp LQ64D341 display, 640x480. 971 Active, color, single scan. 972 973 CONFIG_HLD1045 974 975 HLD1045 display, 640x480. 976 Active, color, single scan. 977 978 CONFIG_OPTREX_BW 979 980 Optrex CBL50840-2 NF-FW 99 22 M5 981 or 982 Hitachi LMG6912RPFC-00T 983 or 984 Hitachi SP14Q002 985 986 320x240. Black & white. 987 988 Normally display is black on white background; define 989 CFG_WHITE_ON_BLACK to get it inverted. 990 991- Splash Screen Support: CONFIG_SPLASH_SCREEN 992 993 If this option is set, the environment is checked for 994 a variable "splashimage". If found, the usual display 995 of logo, copyright and system information on the LCD 996 is suppressed and the BMP image at the address 997 specified in "splashimage" is loaded instead. The 998 console is redirected to the "nulldev", too. This 999 allows for a "silent" boot where a splash screen is 1000 loaded very quickly after power-on. 1001 1002- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP 1003 1004 If this option is set, additionally to standard BMP 1005 images, gzipped BMP images can be displayed via the 1006 splashscreen support or the bmp command. 1007 1008- Compression support: 1009 CONFIG_BZIP2 1010 1011 If this option is set, support for bzip2 compressed 1012 images is included. If not, only uncompressed and gzip 1013 compressed images are supported. 1014 1015 NOTE: the bzip2 algorithm requires a lot of RAM, so 1016 the malloc area (as defined by CFG_MALLOC_LEN) should 1017 be at least 4MB. 1018 1019- MII/PHY support: 1020 CONFIG_PHY_ADDR 1021 1022 The address of PHY on MII bus. 1023 1024 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1025 1026 The clock frequency of the MII bus 1027 1028 CONFIG_PHY_GIGE 1029 1030 If this option is set, support for speed/duplex 1031 detection of Gigabit PHY is included. 1032 1033 CONFIG_PHY_RESET_DELAY 1034 1035 Some PHY like Intel LXT971A need extra delay after 1036 reset before any MII register access is possible. 1037 For such PHY, set this option to the usec delay 1038 required. (minimum 300usec for LXT971A) 1039 1040 CONFIG_PHY_CMD_DELAY (ppc4xx) 1041 1042 Some PHY like Intel LXT971A need extra delay after 1043 command issued before MII status register can be read 1044 1045- Ethernet address: 1046 CONFIG_ETHADDR 1047 CONFIG_ETH2ADDR 1048 CONFIG_ETH3ADDR 1049 1050 Define a default value for ethernet address to use 1051 for the respective ethernet interface, in case this 1052 is not determined automatically. 1053 1054- IP address: 1055 CONFIG_IPADDR 1056 1057 Define a default value for the IP address to use for 1058 the default ethernet interface, in case this is not 1059 determined through e.g. bootp. 1060 1061- Server IP address: 1062 CONFIG_SERVERIP 1063 1064 Defines a default value for theIP address of a TFTP 1065 server to contact when using the "tftboot" command. 1066 1067- Multicast TFTP Mode: 1068 CONFIG_MCAST_TFTP 1069 1070 Defines whether you want to support multicast TFTP as per 1071 rfc-2090; for example to work with atftp. Lets lots of targets 1072 tftp down the same boot image concurrently. Note: the ethernet 1073 driver in use must provide a function: mcast() to join/leave a 1074 multicast group. 1075 1076 CONFIG_BOOTP_RANDOM_DELAY 1077- BOOTP Recovery Mode: 1078 CONFIG_BOOTP_RANDOM_DELAY 1079 1080 If you have many targets in a network that try to 1081 boot using BOOTP, you may want to avoid that all 1082 systems send out BOOTP requests at precisely the same 1083 moment (which would happen for instance at recovery 1084 from a power failure, when all systems will try to 1085 boot, thus flooding the BOOTP server. Defining 1086 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1087 inserted before sending out BOOTP requests. The 1088 following delays are inserted then: 1089 1090 1st BOOTP request: delay 0 ... 1 sec 1091 2nd BOOTP request: delay 0 ... 2 sec 1092 3rd BOOTP request: delay 0 ... 4 sec 1093 4th and following 1094 BOOTP requests: delay 0 ... 8 sec 1095 1096- DHCP Advanced Options: 1097 You can fine tune the DHCP functionality by defining 1098 CONFIG_BOOTP_* symbols: 1099 1100 CONFIG_BOOTP_SUBNETMASK 1101 CONFIG_BOOTP_GATEWAY 1102 CONFIG_BOOTP_HOSTNAME 1103 CONFIG_BOOTP_NISDOMAIN 1104 CONFIG_BOOTP_BOOTPATH 1105 CONFIG_BOOTP_BOOTFILESIZE 1106 CONFIG_BOOTP_DNS 1107 CONFIG_BOOTP_DNS2 1108 CONFIG_BOOTP_SEND_HOSTNAME 1109 CONFIG_BOOTP_NTPSERVER 1110 CONFIG_BOOTP_TIMEOFFSET 1111 CONFIG_BOOTP_VENDOREX 1112 1113 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1114 environment variable, not the BOOTP server. 1115 1116 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS 1117 serverip from a DHCP server, it is possible that more 1118 than one DNS serverip is offered to the client. 1119 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS 1120 serverip will be stored in the additional environment 1121 variable "dnsip2". The first DNS serverip is always 1122 stored in the variable "dnsip", when CONFIG_BOOTP_DNS 1123 is defined. 1124 1125 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable 1126 to do a dynamic update of a DNS server. To do this, they 1127 need the hostname of the DHCP requester. 1128 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content 1129 of the "hostname" environment variable is passed as 1130 option 12 to the DHCP server. 1131 1132 - CDP Options: 1133 CONFIG_CDP_DEVICE_ID 1134 1135 The device id used in CDP trigger frames. 1136 1137 CONFIG_CDP_DEVICE_ID_PREFIX 1138 1139 A two character string which is prefixed to the MAC address 1140 of the device. 1141 1142 CONFIG_CDP_PORT_ID 1143 1144 A printf format string which contains the ascii name of 1145 the port. Normally is set to "eth%d" which sets 1146 eth0 for the first ethernet, eth1 for the second etc. 1147 1148 CONFIG_CDP_CAPABILITIES 1149 1150 A 32bit integer which indicates the device capabilities; 1151 0x00000010 for a normal host which does not forwards. 1152 1153 CONFIG_CDP_VERSION 1154 1155 An ascii string containing the version of the software. 1156 1157 CONFIG_CDP_PLATFORM 1158 1159 An ascii string containing the name of the platform. 1160 1161 CONFIG_CDP_TRIGGER 1162 1163 A 32bit integer sent on the trigger. 1164 1165 CONFIG_CDP_POWER_CONSUMPTION 1166 1167 A 16bit integer containing the power consumption of the 1168 device in .1 of milliwatts. 1169 1170 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1171 1172 A byte containing the id of the VLAN. 1173 1174- Status LED: CONFIG_STATUS_LED 1175 1176 Several configurations allow to display the current 1177 status using a LED. For instance, the LED will blink 1178 fast while running U-Boot code, stop blinking as 1179 soon as a reply to a BOOTP request was received, and 1180 start blinking slow once the Linux kernel is running 1181 (supported by a status LED driver in the Linux 1182 kernel). Defining CONFIG_STATUS_LED enables this 1183 feature in U-Boot. 1184 1185- CAN Support: CONFIG_CAN_DRIVER 1186 1187 Defining CONFIG_CAN_DRIVER enables CAN driver support 1188 on those systems that support this (optional) 1189 feature, like the TQM8xxL modules. 1190 1191- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C 1192 1193 These enable I2C serial bus commands. Defining either of 1194 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will 1195 include the appropriate I2C driver for the selected cpu. 1196 1197 This will allow you to use i2c commands at the u-boot 1198 command line (as long as you set CONFIG_CMD_I2C in 1199 CONFIG_COMMANDS) and communicate with i2c based realtime 1200 clock chips. See common/cmd_i2c.c for a description of the 1201 command line interface. 1202 1203 CONFIG_I2C_CMD_TREE is a recommended option that places 1204 all I2C commands under a single 'i2c' root command. The 1205 older 'imm', 'imd', 'iprobe' etc. commands are considered 1206 deprecated and may disappear in the future. 1207 1208 CONFIG_HARD_I2C selects a hardware I2C controller. 1209 1210 CONFIG_SOFT_I2C configures u-boot to use a software (aka 1211 bit-banging) driver instead of CPM or similar hardware 1212 support for I2C. 1213 1214 There are several other quantities that must also be 1215 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C. 1216 1217 In both cases you will need to define CFG_I2C_SPEED 1218 to be the frequency (in Hz) at which you wish your i2c bus 1219 to run and CFG_I2C_SLAVE to be the address of this node (ie 1220 the cpu's i2c node address). 1221 1222 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c) 1223 sets the cpu up as a master node and so its address should 1224 therefore be cleared to 0 (See, eg, MPC823e User's Manual 1225 p.16-473). So, set CFG_I2C_SLAVE to 0. 1226 1227 That's all that's required for CONFIG_HARD_I2C. 1228 1229 If you use the software i2c interface (CONFIG_SOFT_I2C) 1230 then the following macros need to be defined (examples are 1231 from include/configs/lwmon.h): 1232 1233 I2C_INIT 1234 1235 (Optional). Any commands necessary to enable the I2C 1236 controller or configure ports. 1237 1238 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1239 1240 I2C_PORT 1241 1242 (Only for MPC8260 CPU). The I/O port to use (the code 1243 assumes both bits are on the same port). Valid values 1244 are 0..3 for ports A..D. 1245 1246 I2C_ACTIVE 1247 1248 The code necessary to make the I2C data line active 1249 (driven). If the data line is open collector, this 1250 define can be null. 1251 1252 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1253 1254 I2C_TRISTATE 1255 1256 The code necessary to make the I2C data line tri-stated 1257 (inactive). If the data line is open collector, this 1258 define can be null. 1259 1260 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1261 1262 I2C_READ 1263 1264 Code that returns TRUE if the I2C data line is high, 1265 FALSE if it is low. 1266 1267 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1268 1269 I2C_SDA(bit) 1270 1271 If <bit> is TRUE, sets the I2C data line high. If it 1272 is FALSE, it clears it (low). 1273 1274 eg: #define I2C_SDA(bit) \ 1275 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1276 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1277 1278 I2C_SCL(bit) 1279 1280 If <bit> is TRUE, sets the I2C clock line high. If it 1281 is FALSE, it clears it (low). 1282 1283 eg: #define I2C_SCL(bit) \ 1284 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1285 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1286 1287 I2C_DELAY 1288 1289 This delay is invoked four times per clock cycle so this 1290 controls the rate of data transfer. The data rate thus 1291 is 1 / (I2C_DELAY * 4). Often defined to be something 1292 like: 1293 1294 #define I2C_DELAY udelay(2) 1295 1296 CFG_I2C_INIT_BOARD 1297 1298 When a board is reset during an i2c bus transfer 1299 chips might think that the current transfer is still 1300 in progress. On some boards it is possible to access 1301 the i2c SCLK line directly, either by using the 1302 processor pin as a GPIO or by having a second pin 1303 connected to the bus. If this option is defined a 1304 custom i2c_init_board() routine in boards/xxx/board.c 1305 is run early in the boot sequence. 1306 1307 CONFIG_I2CFAST (PPC405GP|PPC405EP only) 1308 1309 This option enables configuration of bi_iic_fast[] flags 1310 in u-boot bd_info structure based on u-boot environment 1311 variable "i2cfast". (see also i2cfast) 1312 1313 CONFIG_I2C_MULTI_BUS 1314 1315 This option allows the use of multiple I2C buses, each of which 1316 must have a controller. At any point in time, only one bus is 1317 active. To switch to a different bus, use the 'i2c dev' command. 1318 Note that bus numbering is zero-based. 1319 1320 CFG_I2C_NOPROBES 1321 1322 This option specifies a list of I2C devices that will be skipped 1323 when the 'i2c probe' command is issued (or 'iprobe' using the legacy 1324 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device 1325 pairs. Otherwise, specify a 1D array of device addresses 1326 1327 e.g. 1328 #undef CONFIG_I2C_MULTI_BUS 1329 #define CFG_I2C_NOPROBES {0x50,0x68} 1330 1331 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1332 1333 #define CONFIG_I2C_MULTI_BUS 1334 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1335 1336 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1337 1338 CFG_SPD_BUS_NUM 1339 1340 If defined, then this indicates the I2C bus number for DDR SPD. 1341 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1342 1343 CFG_RTC_BUS_NUM 1344 1345 If defined, then this indicates the I2C bus number for the RTC. 1346 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1347 1348 CFG_DTT_BUS_NUM 1349 1350 If defined, then this indicates the I2C bus number for the DTT. 1351 If not defined, then U-Boot assumes that DTT is on I2C bus 0. 1352 1353 CONFIG_FSL_I2C 1354 1355 Define this option if you want to use Freescale's I2C driver in 1356 drivers/i2c/fsl_i2c.c. 1357 1358 1359- SPI Support: CONFIG_SPI 1360 1361 Enables SPI driver (so far only tested with 1362 SPI EEPROM, also an instance works with Crystal A/D and 1363 D/As on the SACSng board) 1364 1365 CONFIG_SPI_X 1366 1367 Enables extended (16-bit) SPI EEPROM addressing. 1368 (symmetrical to CONFIG_I2C_X) 1369 1370 CONFIG_SOFT_SPI 1371 1372 Enables a software (bit-bang) SPI driver rather than 1373 using hardware support. This is a general purpose 1374 driver that only requires three general I/O port pins 1375 (two outputs, one input) to function. If this is 1376 defined, the board configuration must define several 1377 SPI configuration items (port pins to use, etc). For 1378 an example, see include/configs/sacsng.h. 1379 1380- FPGA Support: CONFIG_FPGA 1381 1382 Enables FPGA subsystem. 1383 1384 CONFIG_FPGA_<vendor> 1385 1386 Enables support for specific chip vendors. 1387 (ALTERA, XILINX) 1388 1389 CONFIG_FPGA_<family> 1390 1391 Enables support for FPGA family. 1392 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1393 1394 CONFIG_FPGA_COUNT 1395 1396 Specify the number of FPGA devices to support. 1397 1398 CFG_FPGA_PROG_FEEDBACK 1399 1400 Enable printing of hash marks during FPGA configuration. 1401 1402 CFG_FPGA_CHECK_BUSY 1403 1404 Enable checks on FPGA configuration interface busy 1405 status by the configuration function. This option 1406 will require a board or device specific function to 1407 be written. 1408 1409 CONFIG_FPGA_DELAY 1410 1411 If defined, a function that provides delays in the FPGA 1412 configuration driver. 1413 1414 CFG_FPGA_CHECK_CTRLC 1415 Allow Control-C to interrupt FPGA configuration 1416 1417 CFG_FPGA_CHECK_ERROR 1418 1419 Check for configuration errors during FPGA bitfile 1420 loading. For example, abort during Virtex II 1421 configuration if the INIT_B line goes low (which 1422 indicated a CRC error). 1423 1424 CFG_FPGA_WAIT_INIT 1425 1426 Maximum time to wait for the INIT_B line to deassert 1427 after PROB_B has been deasserted during a Virtex II 1428 FPGA configuration sequence. The default time is 500 1429 mS. 1430 1431 CFG_FPGA_WAIT_BUSY 1432 1433 Maximum time to wait for BUSY to deassert during 1434 Virtex II FPGA configuration. The default is 5 mS. 1435 1436 CFG_FPGA_WAIT_CONFIG 1437 1438 Time to wait after FPGA configuration. The default is 1439 200 mS. 1440 1441- Configuration Management: 1442 CONFIG_IDENT_STRING 1443 1444 If defined, this string will be added to the U-Boot 1445 version information (U_BOOT_VERSION) 1446 1447- Vendor Parameter Protection: 1448 1449 U-Boot considers the values of the environment 1450 variables "serial#" (Board Serial Number) and 1451 "ethaddr" (Ethernet Address) to be parameters that 1452 are set once by the board vendor / manufacturer, and 1453 protects these variables from casual modification by 1454 the user. Once set, these variables are read-only, 1455 and write or delete attempts are rejected. You can 1456 change this behviour: 1457 1458 If CONFIG_ENV_OVERWRITE is #defined in your config 1459 file, the write protection for vendor parameters is 1460 completely disabled. Anybody can change or delete 1461 these parameters. 1462 1463 Alternatively, if you #define _both_ CONFIG_ETHADDR 1464 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1465 ethernet address is installed in the environment, 1466 which can be changed exactly ONCE by the user. [The 1467 serial# is unaffected by this, i. e. it remains 1468 read-only.] 1469 1470- Protected RAM: 1471 CONFIG_PRAM 1472 1473 Define this variable to enable the reservation of 1474 "protected RAM", i. e. RAM which is not overwritten 1475 by U-Boot. Define CONFIG_PRAM to hold the number of 1476 kB you want to reserve for pRAM. You can overwrite 1477 this default value by defining an environment 1478 variable "pram" to the number of kB you want to 1479 reserve. Note that the board info structure will 1480 still show the full amount of RAM. If pRAM is 1481 reserved, a new environment variable "mem" will 1482 automatically be defined to hold the amount of 1483 remaining RAM in a form that can be passed as boot 1484 argument to Linux, for instance like that: 1485 1486 setenv bootargs ... mem=\${mem} 1487 saveenv 1488 1489 This way you can tell Linux not to use this memory, 1490 either, which results in a memory region that will 1491 not be affected by reboots. 1492 1493 *WARNING* If your board configuration uses automatic 1494 detection of the RAM size, you must make sure that 1495 this memory test is non-destructive. So far, the 1496 following board configurations are known to be 1497 "pRAM-clean": 1498 1499 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, 1500 HERMES, IP860, RPXlite, LWMON, LANTEC, 1501 PCU_E, FLAGADM, TQM8260 1502 1503- Error Recovery: 1504 CONFIG_PANIC_HANG 1505 1506 Define this variable to stop the system in case of a 1507 fatal error, so that you have to reset it manually. 1508 This is probably NOT a good idea for an embedded 1509 system where you want to system to reboot 1510 automatically as fast as possible, but it may be 1511 useful during development since you can try to debug 1512 the conditions that lead to the situation. 1513 1514 CONFIG_NET_RETRY_COUNT 1515 1516 This variable defines the number of retries for 1517 network operations like ARP, RARP, TFTP, or BOOTP 1518 before giving up the operation. If not defined, a 1519 default value of 5 is used. 1520 1521- Command Interpreter: 1522 CONFIG_AUTO_COMPLETE 1523 1524 Enable auto completion of commands using TAB. 1525 1526 Note that this feature has NOT been implemented yet 1527 for the "hush" shell. 1528 1529 1530 CFG_HUSH_PARSER 1531 1532 Define this variable to enable the "hush" shell (from 1533 Busybox) as command line interpreter, thus enabling 1534 powerful command line syntax like 1535 if...then...else...fi conditionals or `&&' and '||' 1536 constructs ("shell scripts"). 1537 1538 If undefined, you get the old, much simpler behaviour 1539 with a somewhat smaller memory footprint. 1540 1541 1542 CFG_PROMPT_HUSH_PS2 1543 1544 This defines the secondary prompt string, which is 1545 printed when the command interpreter needs more input 1546 to complete a command. Usually "> ". 1547 1548 Note: 1549 1550 In the current implementation, the local variables 1551 space and global environment variables space are 1552 separated. Local variables are those you define by 1553 simply typing `name=value'. To access a local 1554 variable later on, you have write `$name' or 1555 `${name}'; to execute the contents of a variable 1556 directly type `$name' at the command prompt. 1557 1558 Global environment variables are those you use 1559 setenv/printenv to work with. To run a command stored 1560 in such a variable, you need to use the run command, 1561 and you must not use the '$' sign to access them. 1562 1563 To store commands and special characters in a 1564 variable, please use double quotation marks 1565 surrounding the whole text of the variable, instead 1566 of the backslashes before semicolons and special 1567 symbols. 1568 1569- Commandline Editing and History: 1570 CONFIG_CMDLINE_EDITING 1571 1572 Enable editiong and History functions for interactive 1573 commandline input operations 1574 1575- Default Environment: 1576 CONFIG_EXTRA_ENV_SETTINGS 1577 1578 Define this to contain any number of null terminated 1579 strings (variable = value pairs) that will be part of 1580 the default environment compiled into the boot image. 1581 1582 For example, place something like this in your 1583 board's config file: 1584 1585 #define CONFIG_EXTRA_ENV_SETTINGS \ 1586 "myvar1=value1\0" \ 1587 "myvar2=value2\0" 1588 1589 Warning: This method is based on knowledge about the 1590 internal format how the environment is stored by the 1591 U-Boot code. This is NOT an official, exported 1592 interface! Although it is unlikely that this format 1593 will change soon, there is no guarantee either. 1594 You better know what you are doing here. 1595 1596 Note: overly (ab)use of the default environment is 1597 discouraged. Make sure to check other ways to preset 1598 the environment like the autoscript function or the 1599 boot command first. 1600 1601- DataFlash Support: 1602 CONFIG_HAS_DATAFLASH 1603 1604 Defining this option enables DataFlash features and 1605 allows to read/write in Dataflash via the standard 1606 commands cp, md... 1607 1608- SystemACE Support: 1609 CONFIG_SYSTEMACE 1610 1611 Adding this option adds support for Xilinx SystemACE 1612 chips attached via some sort of local bus. The address 1613 of the chip must alsh be defined in the 1614 CFG_SYSTEMACE_BASE macro. For example: 1615 1616 #define CONFIG_SYSTEMACE 1617 #define CFG_SYSTEMACE_BASE 0xf0000000 1618 1619 When SystemACE support is added, the "ace" device type 1620 becomes available to the fat commands, i.e. fatls. 1621 1622- TFTP Fixed UDP Port: 1623 CONFIG_TFTP_PORT 1624 1625 If this is defined, the environment variable tftpsrcp 1626 is used to supply the TFTP UDP source port value. 1627 If tftpsrcp isn't defined, the normal pseudo-random port 1628 number generator is used. 1629 1630 Also, the environment variable tftpdstp is used to supply 1631 the TFTP UDP destination port value. If tftpdstp isn't 1632 defined, the normal port 69 is used. 1633 1634 The purpose for tftpsrcp is to allow a TFTP server to 1635 blindly start the TFTP transfer using the pre-configured 1636 target IP address and UDP port. This has the effect of 1637 "punching through" the (Windows XP) firewall, allowing 1638 the remainder of the TFTP transfer to proceed normally. 1639 A better solution is to properly configure the firewall, 1640 but sometimes that is not allowed. 1641 1642- Show boot progress: 1643 CONFIG_SHOW_BOOT_PROGRESS 1644 1645 Defining this option allows to add some board- 1646 specific code (calling a user-provided function 1647 "show_boot_progress(int)") that enables you to show 1648 the system's boot progress on some display (for 1649 example, some LED's) on your board. At the moment, 1650 the following checkpoints are implemented: 1651 1652 Arg Where When 1653 1 common/cmd_bootm.c before attempting to boot an image 1654 -1 common/cmd_bootm.c Image header has bad magic number 1655 2 common/cmd_bootm.c Image header has correct magic number 1656 -2 common/cmd_bootm.c Image header has bad checksum 1657 3 common/cmd_bootm.c Image header has correct checksum 1658 -3 common/cmd_bootm.c Image data has bad checksum 1659 4 common/cmd_bootm.c Image data has correct checksum 1660 -4 common/cmd_bootm.c Image is for unsupported architecture 1661 5 common/cmd_bootm.c Architecture check OK 1662 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1663 6 common/cmd_bootm.c Image Type check OK 1664 -6 common/cmd_bootm.c gunzip uncompression error 1665 -7 common/cmd_bootm.c Unimplemented compression type 1666 7 common/cmd_bootm.c Uncompression OK 1667 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) 1668 8 common/cmd_bootm.c Image Type check OK 1669 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) 1670 9 common/cmd_bootm.c Start initial ramdisk verification 1671 -10 common/cmd_bootm.c Ramdisk header has bad magic number 1672 -11 common/cmd_bootm.c Ramdisk header has bad checksum 1673 10 common/cmd_bootm.c Ramdisk header is OK 1674 -12 common/cmd_bootm.c Ramdisk data has bad checksum 1675 11 common/cmd_bootm.c Ramdisk data has correct checksum 1676 12 common/cmd_bootm.c Ramdisk verification complete, start loading 1677 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) 1678 13 common/cmd_bootm.c Start multifile image verification 1679 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. 1680 15 common/cmd_bootm.c All preparation done, transferring control to OS 1681 1682 -30 lib_ppc/board.c Fatal error, hang the system 1683 -31 post/post.c POST test failed, detected by post_output_backlog() 1684 -32 post/post.c POST test failed, detected by post_run_single() 1685 1686 34 common/cmd_doc.c before loading a Image from a DOC device 1687 -35 common/cmd_doc.c Bad usage of "doc" command 1688 35 common/cmd_doc.c correct usage of "doc" command 1689 -36 common/cmd_doc.c No boot device 1690 36 common/cmd_doc.c correct boot device 1691 -37 common/cmd_doc.c Unknown Chip ID on boot device 1692 37 common/cmd_doc.c correct chip ID found, device available 1693 -38 common/cmd_doc.c Read Error on boot device 1694 38 common/cmd_doc.c reading Image header from DOC device OK 1695 -39 common/cmd_doc.c Image header has bad magic number 1696 39 common/cmd_doc.c Image header has correct magic number 1697 -40 common/cmd_doc.c Error reading Image from DOC device 1698 40 common/cmd_doc.c Image header has correct magic number 1699 41 common/cmd_ide.c before loading a Image from a IDE device 1700 -42 common/cmd_ide.c Bad usage of "ide" command 1701 42 common/cmd_ide.c correct usage of "ide" command 1702 -43 common/cmd_ide.c No boot device 1703 43 common/cmd_ide.c boot device found 1704 -44 common/cmd_ide.c Device not available 1705 44 common/cmd_ide.c Device available 1706 -45 common/cmd_ide.c wrong partition selected 1707 45 common/cmd_ide.c partition selected 1708 -46 common/cmd_ide.c Unknown partition table 1709 46 common/cmd_ide.c valid partition table found 1710 -47 common/cmd_ide.c Invalid partition type 1711 47 common/cmd_ide.c correct partition type 1712 -48 common/cmd_ide.c Error reading Image Header on boot device 1713 48 common/cmd_ide.c reading Image Header from IDE device OK 1714 -49 common/cmd_ide.c Image header has bad magic number 1715 49 common/cmd_ide.c Image header has correct magic number 1716 -50 common/cmd_ide.c Image header has bad checksum 1717 50 common/cmd_ide.c Image header has correct checksum 1718 -51 common/cmd_ide.c Error reading Image from IDE device 1719 51 common/cmd_ide.c reading Image from IDE device OK 1720 52 common/cmd_nand.c before loading a Image from a NAND device 1721 -53 common/cmd_nand.c Bad usage of "nand" command 1722 53 common/cmd_nand.c correct usage of "nand" command 1723 -54 common/cmd_nand.c No boot device 1724 54 common/cmd_nand.c boot device found 1725 -55 common/cmd_nand.c Unknown Chip ID on boot device 1726 55 common/cmd_nand.c correct chip ID found, device available 1727 -56 common/cmd_nand.c Error reading Image Header on boot device 1728 56 common/cmd_nand.c reading Image Header from NAND device OK 1729 -57 common/cmd_nand.c Image header has bad magic number 1730 57 common/cmd_nand.c Image header has correct magic number 1731 -58 common/cmd_nand.c Error reading Image from NAND device 1732 58 common/cmd_nand.c reading Image from NAND device OK 1733 1734 -60 common/env_common.c Environment has a bad CRC, using default 1735 1736 64 net/eth.c starting with Ethernetconfiguration. 1737 -64 net/eth.c no Ethernet found. 1738 65 net/eth.c Ethernet found. 1739 1740 -80 common/cmd_net.c usage wrong 1741 80 common/cmd_net.c before calling NetLoop() 1742 -81 common/cmd_net.c some error in NetLoop() occured 1743 81 common/cmd_net.c NetLoop() back without error 1744 -82 common/cmd_net.c size == 0 (File with size 0 loaded) 1745 82 common/cmd_net.c trying automatic boot 1746 83 common/cmd_net.c running autoscript 1747 -83 common/cmd_net.c some error in automatic boot or autoscript 1748 84 common/cmd_net.c end without errors 1749 1750Modem Support: 1751-------------- 1752 1753[so far only for SMDK2400 and TRAB boards] 1754 1755- Modem support endable: 1756 CONFIG_MODEM_SUPPORT 1757 1758- RTS/CTS Flow control enable: 1759 CONFIG_HWFLOW 1760 1761- Modem debug support: 1762 CONFIG_MODEM_SUPPORT_DEBUG 1763 1764 Enables debugging stuff (char screen[1024], dbg()) 1765 for modem support. Useful only with BDI2000. 1766 1767- Interrupt support (PPC): 1768 1769 There are common interrupt_init() and timer_interrupt() 1770 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1771 for cpu specific initialization. interrupt_init_cpu() 1772 should set decrementer_count to appropriate value. If 1773 cpu resets decrementer automatically after interrupt 1774 (ppc4xx) it should set decrementer_count to zero. 1775 timer_interrupt() calls timer_interrupt_cpu() for cpu 1776 specific handling. If board has watchdog / status_led 1777 / other_activity_monitor it works automatically from 1778 general timer_interrupt(). 1779 1780- General: 1781 1782 In the target system modem support is enabled when a 1783 specific key (key combination) is pressed during 1784 power-on. Otherwise U-Boot will boot normally 1785 (autoboot). The key_pressed() fuction is called from 1786 board_init(). Currently key_pressed() is a dummy 1787 function, returning 1 and thus enabling modem 1788 initialization. 1789 1790 If there are no modem init strings in the 1791 environment, U-Boot proceed to autoboot; the 1792 previous output (banner, info printfs) will be 1793 supressed, though. 1794 1795 See also: doc/README.Modem 1796 1797 1798Configuration Settings: 1799----------------------- 1800 1801- CFG_LONGHELP: Defined when you want long help messages included; 1802 undefine this when you're short of memory. 1803 1804- CFG_PROMPT: This is what U-Boot prints on the console to 1805 prompt for user input. 1806 1807- CFG_CBSIZE: Buffer size for input from the Console 1808 1809- CFG_PBSIZE: Buffer size for Console output 1810 1811- CFG_MAXARGS: max. Number of arguments accepted for monitor commands 1812 1813- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to 1814 the application (usually a Linux kernel) when it is 1815 booted 1816 1817- CFG_BAUDRATE_TABLE: 1818 List of legal baudrate settings for this board. 1819 1820- CFG_CONSOLE_INFO_QUIET 1821 Suppress display of console information at boot. 1822 1823- CFG_CONSOLE_IS_IN_ENV 1824 If the board specific function 1825 extern int overwrite_console (void); 1826 returns 1, the stdin, stderr and stdout are switched to the 1827 serial port, else the settings in the environment are used. 1828 1829- CFG_CONSOLE_OVERWRITE_ROUTINE 1830 Enable the call to overwrite_console(). 1831 1832- CFG_CONSOLE_ENV_OVERWRITE 1833 Enable overwrite of previous console environment settings. 1834 1835- CFG_MEMTEST_START, CFG_MEMTEST_END: 1836 Begin and End addresses of the area used by the 1837 simple memory test. 1838 1839- CFG_ALT_MEMTEST: 1840 Enable an alternate, more extensive memory test. 1841 1842- CFG_MEMTEST_SCRATCH: 1843 Scratch address used by the alternate memory test 1844 You only need to set this if address zero isn't writeable 1845 1846- CFG_TFTP_LOADADDR: 1847 Default load address for network file downloads 1848 1849- CFG_LOADS_BAUD_CHANGE: 1850 Enable temporary baudrate change while serial download 1851 1852- CFG_SDRAM_BASE: 1853 Physical start address of SDRAM. _Must_ be 0 here. 1854 1855- CFG_MBIO_BASE: 1856 Physical start address of Motherboard I/O (if using a 1857 Cogent motherboard) 1858 1859- CFG_FLASH_BASE: 1860 Physical start address of Flash memory. 1861 1862- CFG_MONITOR_BASE: 1863 Physical start address of boot monitor code (set by 1864 make config files to be same as the text base address 1865 (TEXT_BASE) used when linking) - same as 1866 CFG_FLASH_BASE when booting from flash. 1867 1868- CFG_MONITOR_LEN: 1869 Size of memory reserved for monitor code, used to 1870 determine _at_compile_time_ (!) if the environment is 1871 embedded within the U-Boot image, or in a separate 1872 flash sector. 1873 1874- CFG_MALLOC_LEN: 1875 Size of DRAM reserved for malloc() use. 1876 1877- CFG_BOOTM_LEN: 1878 Normally compressed uImages are limited to an 1879 uncompressed size of 8 MBytes. If this is not enough, 1880 you can define CFG_BOOTM_LEN in your board config file 1881 to adjust this setting to your needs. 1882 1883- CFG_BOOTMAPSZ: 1884 Maximum size of memory mapped by the startup code of 1885 the Linux kernel; all data that must be processed by 1886 the Linux kernel (bd_info, boot arguments, eventually 1887 initrd image) must be put below this limit. 1888 1889- CFG_MAX_FLASH_BANKS: 1890 Max number of Flash memory banks 1891 1892- CFG_MAX_FLASH_SECT: 1893 Max number of sectors on a Flash chip 1894 1895- CFG_FLASH_ERASE_TOUT: 1896 Timeout for Flash erase operations (in ms) 1897 1898- CFG_FLASH_WRITE_TOUT: 1899 Timeout for Flash write operations (in ms) 1900 1901- CFG_FLASH_LOCK_TOUT 1902 Timeout for Flash set sector lock bit operation (in ms) 1903 1904- CFG_FLASH_UNLOCK_TOUT 1905 Timeout for Flash clear lock bits operation (in ms) 1906 1907- CFG_FLASH_PROTECTION 1908 If defined, hardware flash sectors protection is used 1909 instead of U-Boot software protection. 1910 1911- CFG_DIRECT_FLASH_TFTP: 1912 1913 Enable TFTP transfers directly to flash memory; 1914 without this option such a download has to be 1915 performed in two steps: (1) download to RAM, and (2) 1916 copy from RAM to flash. 1917 1918 The two-step approach is usually more reliable, since 1919 you can check if the download worked before you erase 1920 the flash, but in some situations (when sytem RAM is 1921 too limited to allow for a tempory copy of the 1922 downloaded image) this option may be very useful. 1923 1924- CFG_FLASH_CFI: 1925 Define if the flash driver uses extra elements in the 1926 common flash structure for storing flash geometry. 1927 1928- CFG_FLASH_CFI_DRIVER 1929 This option also enables the building of the cfi_flash driver 1930 in the drivers directory 1931 1932- CFG_FLASH_QUIET_TEST 1933 If this option is defined, the common CFI flash doesn't 1934 print it's warning upon not recognized FLASH banks. This 1935 is useful, if some of the configured banks are only 1936 optionally available. 1937 1938- CFG_RX_ETH_BUFFER: 1939 Defines the number of ethernet receive buffers. On some 1940 ethernet controllers it is recommended to set this value 1941 to 8 or even higher (EEPRO100 or 405 EMAC), since all 1942 buffers can be full shortly after enabling the interface 1943 on high ethernet traffic. 1944 Defaults to 4 if not defined. 1945 1946The following definitions that deal with the placement and management 1947of environment data (variable area); in general, we support the 1948following configurations: 1949 1950- CFG_ENV_IS_IN_FLASH: 1951 1952 Define this if the environment is in flash memory. 1953 1954 a) The environment occupies one whole flash sector, which is 1955 "embedded" in the text segment with the U-Boot code. This 1956 happens usually with "bottom boot sector" or "top boot 1957 sector" type flash chips, which have several smaller 1958 sectors at the start or the end. For instance, such a 1959 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In 1960 such a case you would place the environment in one of the 1961 4 kB sectors - with U-Boot code before and after it. With 1962 "top boot sector" type flash chips, you would put the 1963 environment in one of the last sectors, leaving a gap 1964 between U-Boot and the environment. 1965 1966 - CFG_ENV_OFFSET: 1967 1968 Offset of environment data (variable area) to the 1969 beginning of flash memory; for instance, with bottom boot 1970 type flash chips the second sector can be used: the offset 1971 for this sector is given here. 1972 1973 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. 1974 1975 - CFG_ENV_ADDR: 1976 1977 This is just another way to specify the start address of 1978 the flash sector containing the environment (instead of 1979 CFG_ENV_OFFSET). 1980 1981 - CFG_ENV_SECT_SIZE: 1982 1983 Size of the sector containing the environment. 1984 1985 1986 b) Sometimes flash chips have few, equal sized, BIG sectors. 1987 In such a case you don't want to spend a whole sector for 1988 the environment. 1989 1990 - CFG_ENV_SIZE: 1991 1992 If you use this in combination with CFG_ENV_IS_IN_FLASH 1993 and CFG_ENV_SECT_SIZE, you can specify to use only a part 1994 of this flash sector for the environment. This saves 1995 memory for the RAM copy of the environment. 1996 1997 It may also save flash memory if you decide to use this 1998 when your environment is "embedded" within U-Boot code, 1999 since then the remainder of the flash sector could be used 2000 for U-Boot code. It should be pointed out that this is 2001 STRONGLY DISCOURAGED from a robustness point of view: 2002 updating the environment in flash makes it always 2003 necessary to erase the WHOLE sector. If something goes 2004 wrong before the contents has been restored from a copy in 2005 RAM, your target system will be dead. 2006 2007 - CFG_ENV_ADDR_REDUND 2008 CFG_ENV_SIZE_REDUND 2009 2010 These settings describe a second storage area used to hold 2011 a redundand copy of the environment data, so that there is 2012 a valid backup copy in case there is a power failure during 2013 a "saveenv" operation. 2014 2015BE CAREFUL! Any changes to the flash layout, and some changes to the 2016source code will make it necessary to adapt <board>/u-boot.lds* 2017accordingly! 2018 2019 2020- CFG_ENV_IS_IN_NVRAM: 2021 2022 Define this if you have some non-volatile memory device 2023 (NVRAM, battery buffered SRAM) which you want to use for the 2024 environment. 2025 2026 - CFG_ENV_ADDR: 2027 - CFG_ENV_SIZE: 2028 2029 These two #defines are used to determin the memory area you 2030 want to use for environment. It is assumed that this memory 2031 can just be read and written to, without any special 2032 provision. 2033 2034BE CAREFUL! The first access to the environment happens quite early 2035in U-Boot initalization (when we try to get the setting of for the 2036console baudrate). You *MUST* have mappend your NVRAM area then, or 2037U-Boot will hang. 2038 2039Please note that even with NVRAM we still use a copy of the 2040environment in RAM: we could work on NVRAM directly, but we want to 2041keep settings there always unmodified except somebody uses "saveenv" 2042to save the current settings. 2043 2044 2045- CFG_ENV_IS_IN_EEPROM: 2046 2047 Use this if you have an EEPROM or similar serial access 2048 device and a driver for it. 2049 2050 - CFG_ENV_OFFSET: 2051 - CFG_ENV_SIZE: 2052 2053 These two #defines specify the offset and size of the 2054 environment area within the total memory of your EEPROM. 2055 2056 - CFG_I2C_EEPROM_ADDR: 2057 If defined, specified the chip address of the EEPROM device. 2058 The default address is zero. 2059 2060 - CFG_EEPROM_PAGE_WRITE_BITS: 2061 If defined, the number of bits used to address bytes in a 2062 single page in the EEPROM device. A 64 byte page, for example 2063 would require six bits. 2064 2065 - CFG_EEPROM_PAGE_WRITE_DELAY_MS: 2066 If defined, the number of milliseconds to delay between 2067 page writes. The default is zero milliseconds. 2068 2069 - CFG_I2C_EEPROM_ADDR_LEN: 2070 The length in bytes of the EEPROM memory array address. Note 2071 that this is NOT the chip address length! 2072 2073 - CFG_I2C_EEPROM_ADDR_OVERFLOW: 2074 EEPROM chips that implement "address overflow" are ones 2075 like Catalyst 24WC04/08/16 which has 9/10/11 bits of 2076 address and the extra bits end up in the "chip address" bit 2077 slots. This makes a 24WC08 (1Kbyte) chip look like four 256 2078 byte chips. 2079 2080 Note that we consider the length of the address field to 2081 still be one byte because the extra address bits are hidden 2082 in the chip address. 2083 2084 - CFG_EEPROM_SIZE: 2085 The size in bytes of the EEPROM device. 2086 2087 2088- CFG_ENV_IS_IN_DATAFLASH: 2089 2090 Define this if you have a DataFlash memory device which you 2091 want to use for the environment. 2092 2093 - CFG_ENV_OFFSET: 2094 - CFG_ENV_ADDR: 2095 - CFG_ENV_SIZE: 2096 2097 These three #defines specify the offset and size of the 2098 environment area within the total memory of your DataFlash placed 2099 at the specified address. 2100 2101- CFG_ENV_IS_IN_NAND: 2102 2103 Define this if you have a NAND device which you want to use 2104 for the environment. 2105 2106 - CFG_ENV_OFFSET: 2107 - CFG_ENV_SIZE: 2108 2109 These two #defines specify the offset and size of the environment 2110 area within the first NAND device. 2111 2112 - CFG_ENV_OFFSET_REDUND 2113 2114 This setting describes a second storage area of CFG_ENV_SIZE 2115 size used to hold a redundant copy of the environment data, 2116 so that there is a valid backup copy in case there is a 2117 power failure during a "saveenv" operation. 2118 2119 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned 2120 to a block boundary, and CFG_ENV_SIZE must be a multiple of 2121 the NAND devices block size. 2122 2123- CFG_SPI_INIT_OFFSET 2124 2125 Defines offset to the initial SPI buffer area in DPRAM. The 2126 area is used at an early stage (ROM part) if the environment 2127 is configured to reside in the SPI EEPROM: We need a 520 byte 2128 scratch DPRAM area. It is used between the two initialization 2129 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems 2130 to be a good choice since it makes it far enough from the 2131 start of the data area as well as from the stack pointer. 2132 2133Please note that the environment is read-only until the monitor 2134has been relocated to RAM and a RAM copy of the environment has been 2135created; also, when using EEPROM you will have to use getenv_r() 2136until then to read environment variables. 2137 2138The environment is protected by a CRC32 checksum. Before the monitor 2139is relocated into RAM, as a result of a bad CRC you will be working 2140with the compiled-in default environment - *silently*!!! [This is 2141necessary, because the first environment variable we need is the 2142"baudrate" setting for the console - if we have a bad CRC, we don't 2143have any device yet where we could complain.] 2144 2145Note: once the monitor has been relocated, then it will complain if 2146the default environment is used; a new CRC is computed as soon as you 2147use the "saveenv" command to store a valid environment. 2148 2149- CFG_FAULT_ECHO_LINK_DOWN: 2150 Echo the inverted Ethernet link state to the fault LED. 2151 2152 Note: If this option is active, then CFG_FAULT_MII_ADDR 2153 also needs to be defined. 2154 2155- CFG_FAULT_MII_ADDR: 2156 MII address of the PHY to check for the Ethernet link state. 2157 2158- CFG_64BIT_VSPRINTF: 2159 Makes vsprintf (and all *printf functions) support printing 2160 of 64bit values by using the L quantifier 2161 2162- CFG_64BIT_STRTOUL: 2163 Adds simple_strtoull that returns a 64bit value 2164 2165Low Level (hardware related) configuration options: 2166--------------------------------------------------- 2167 2168- CFG_CACHELINE_SIZE: 2169 Cache Line Size of the CPU. 2170 2171- CFG_DEFAULT_IMMR: 2172 Default address of the IMMR after system reset. 2173 2174 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU, 2175 and RPXsuper) to be able to adjust the position of 2176 the IMMR register after a reset. 2177 2178- Floppy Disk Support: 2179 CFG_FDC_DRIVE_NUMBER 2180 2181 the default drive number (default value 0) 2182 2183 CFG_ISA_IO_STRIDE 2184 2185 defines the spacing between fdc chipset registers 2186 (default value 1) 2187 2188 CFG_ISA_IO_OFFSET 2189 2190 defines the offset of register from address. It 2191 depends on which part of the data bus is connected to 2192 the fdc chipset. (default value 0) 2193 2194 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and 2195 CFG_FDC_DRIVE_NUMBER are undefined, they take their 2196 default value. 2197 2198 if CFG_FDC_HW_INIT is defined, then the function 2199 fdc_hw_init() is called at the beginning of the FDC 2200 setup. fdc_hw_init() must be provided by the board 2201 source code. It is used to make hardware dependant 2202 initializations. 2203 2204- CFG_IMMR: Physical address of the Internal Memory. 2205 DO NOT CHANGE unless you know exactly what you're 2206 doing! (11-4) [MPC8xx/82xx systems only] 2207 2208- CFG_INIT_RAM_ADDR: 2209 2210 Start address of memory area that can be used for 2211 initial data and stack; please note that this must be 2212 writable memory that is working WITHOUT special 2213 initialization, i. e. you CANNOT use normal RAM which 2214 will become available only after programming the 2215 memory controller and running certain initialization 2216 sequences. 2217 2218 U-Boot uses the following memory types: 2219 - MPC8xx and MPC8260: IMMR (internal memory of the CPU) 2220 - MPC824X: data cache 2221 - PPC4xx: data cache 2222 2223- CFG_GBL_DATA_OFFSET: 2224 2225 Offset of the initial data structure in the memory 2226 area defined by CFG_INIT_RAM_ADDR. Usually 2227 CFG_GBL_DATA_OFFSET is chosen such that the initial 2228 data is located at the end of the available space 2229 (sometimes written as (CFG_INIT_RAM_END - 2230 CFG_INIT_DATA_SIZE), and the initial stack is just 2231 below that area (growing from (CFG_INIT_RAM_ADDR + 2232 CFG_GBL_DATA_OFFSET) downward. 2233 2234 Note: 2235 On the MPC824X (or other systems that use the data 2236 cache for initial memory) the address chosen for 2237 CFG_INIT_RAM_ADDR is basically arbitrary - it must 2238 point to an otherwise UNUSED address space between 2239 the top of RAM and the start of the PCI space. 2240 2241- CFG_SIUMCR: SIU Module Configuration (11-6) 2242 2243- CFG_SYPCR: System Protection Control (11-9) 2244 2245- CFG_TBSCR: Time Base Status and Control (11-26) 2246 2247- CFG_PISCR: Periodic Interrupt Status and Control (11-31) 2248 2249- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) 2250 2251- CFG_SCCR: System Clock and reset Control Register (15-27) 2252 2253- CFG_OR_TIMING_SDRAM: 2254 SDRAM timing 2255 2256- CFG_MAMR_PTA: 2257 periodic timer for refresh 2258 2259- CFG_DER: Debug Event Register (37-47) 2260 2261- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, 2262 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, 2263 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, 2264 CFG_BR1_PRELIM: 2265 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 2266 2267- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 2268 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, 2269 CFG_OR3_PRELIM, CFG_BR3_PRELIM: 2270 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 2271 2272- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, 2273 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: 2274 Machine Mode Register and Memory Periodic Timer 2275 Prescaler definitions (SDRAM timing) 2276 2277- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: 2278 enable I2C microcode relocation patch (MPC8xx); 2279 define relocation offset in DPRAM [DSP2] 2280 2281- CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]: 2282 enable SMC microcode relocation patch (MPC8xx); 2283 define relocation offset in DPRAM [SMC1] 2284 2285- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: 2286 enable SPI microcode relocation patch (MPC8xx); 2287 define relocation offset in DPRAM [SCC4] 2288 2289- CFG_USE_OSCCLK: 2290 Use OSCM clock mode on MBX8xx board. Be careful, 2291 wrong setting might damage your board. Read 2292 doc/README.MBX before setting this variable! 2293 2294- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only) 2295 Offset of the bootmode word in DPRAM used by post 2296 (Power On Self Tests). This definition overrides 2297 #define'd default value in commproc.h resp. 2298 cpm_8260.h. 2299 2300- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, 2301 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, 2302 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS, 2303 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, 2304 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, 2305 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, 2306 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, 2307 CFG_POCMR2_MASK_ATTRIB: (MPC826x only) 2308 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set. 2309 2310- CONFIG_SPD_EEPROM 2311 Get DDR timing information from an I2C EEPROM. Common with pluggable 2312 memory modules such as SODIMMs 2313 SPD_EEPROM_ADDRESS 2314 I2C address of the SPD EEPROM 2315 2316- CFG_SPD_BUS_NUM 2317 If SPD EEPROM is on an I2C bus other than the first one, specify here. 2318 Note that the value must resolve to something your driver can deal with. 2319 2320- CFG_83XX_DDR_USES_CS0 2321 Only for 83xx systems. If specified, then DDR should be configured 2322 using CS0 and CS1 instead of CS2 and CS3. 2323 2324- CFG_83XX_DDR_USES_CS0 2325 Only for 83xx systems. If specified, then DDR should be configured 2326 using CS0 and CS1 instead of CS2 and CS3. 2327 2328- CONFIG_ETHER_ON_FEC[12] 2329 Define to enable FEC[12] on a 8xx series processor. 2330 2331- CONFIG_FEC[12]_PHY 2332 Define to the hardcoded PHY address which corresponds 2333 to the given FEC; i. e. 2334 #define CONFIG_FEC1_PHY 4 2335 means that the PHY with address 4 is connected to FEC1 2336 2337 When set to -1, means to probe for first available. 2338 2339- CONFIG_FEC[12]_PHY_NORXERR 2340 The PHY does not have a RXERR line (RMII only). 2341 (so program the FEC to ignore it). 2342 2343- CONFIG_RMII 2344 Enable RMII mode for all FECs. 2345 Note that this is a global option, we can't 2346 have one FEC in standard MII mode and another in RMII mode. 2347 2348- CONFIG_CRC32_VERIFY 2349 Add a verify option to the crc32 command. 2350 The syntax is: 2351 2352 => crc32 -v <address> <count> <crc32> 2353 2354 Where address/count indicate a memory area 2355 and crc32 is the correct crc32 which the 2356 area should have. 2357 2358- CONFIG_LOOPW 2359 Add the "loopw" memory command. This only takes effect if 2360 the memory commands are activated globally (CONFIG_CMD_MEM). 2361 2362- CONFIG_MX_CYCLIC 2363 Add the "mdc" and "mwc" memory commands. These are cyclic 2364 "md/mw" commands. 2365 Examples: 2366 2367 => mdc.b 10 4 500 2368 This command will print 4 bytes (10,11,12,13) each 500 ms. 2369 2370 => mwc.l 100 12345678 10 2371 This command will write 12345678 to address 100 all 10 ms. 2372 2373 This only takes effect if the memory commands are activated 2374 globally (CONFIG_CMD_MEM). 2375 2376- CONFIG_SKIP_LOWLEVEL_INIT 2377- CONFIG_SKIP_RELOCATE_UBOOT 2378 2379 [ARM only] If these variables are defined, then 2380 certain low level initializations (like setting up 2381 the memory controller) are omitted and/or U-Boot does 2382 not relocate itself into RAM. 2383 Normally these variables MUST NOT be defined. The 2384 only exception is when U-Boot is loaded (to RAM) by 2385 some other boot loader or by a debugger which 2386 performs these intializations itself. 2387 2388 2389Building the Software: 2390====================== 2391 2392Building U-Boot has been tested in native PPC environments (on a 2393PowerBook G3 running LinuxPPC 2000) and in cross environments 2394(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and 2395NetBSD 1.5 on x86). 2396 2397If you are not using a native PPC environment, it is assumed that you 2398have the GNU cross compiling tools available in your path and named 2399with a prefix of "powerpc-linux-". If this is not the case, (e.g. if 2400you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change 2401the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, 2402change it to: 2403 2404 CROSS_COMPILE = ppc_4xx- 2405 2406 2407U-Boot is intended to be simple to build. After installing the 2408sources you must configure U-Boot for one specific board type. This 2409is done by typing: 2410 2411 make NAME_config 2412 2413where "NAME_config" is the name of one of the existing 2414configurations; see the main Makefile for supported names. 2415 2416Note: for some board special configuration names may exist; check if 2417 additional information is available from the board vendor; for 2418 instance, the TQM823L systems are available without (standard) 2419 or with LCD support. You can select such additional "features" 2420 when chosing the configuration, i. e. 2421 2422 make TQM823L_config 2423 - will configure for a plain TQM823L, i. e. no LCD support 2424 2425 make TQM823L_LCD_config 2426 - will configure for a TQM823L with U-Boot console on LCD 2427 2428 etc. 2429 2430 2431Finally, type "make all", and you should get some working U-Boot 2432images ready for download to / installation on your system: 2433 2434- "u-boot.bin" is a raw binary image 2435- "u-boot" is an image in ELF binary format 2436- "u-boot.srec" is in Motorola S-Record format 2437 2438By default the build is performed locally and the objects are saved 2439in the source directory. One of the two methods can be used to change 2440this behavior and build U-Boot to some external directory: 2441 24421. Add O= to the make command line invocations: 2443 2444 make O=/tmp/build distclean 2445 make O=/tmp/build NAME_config 2446 make O=/tmp/build all 2447 24482. Set environment variable BUILD_DIR to point to the desired location: 2449 2450 export BUILD_DIR=/tmp/build 2451 make distclean 2452 make NAME_config 2453 make all 2454 2455Note that the command line "O=" setting overrides the BUILD_DIR environment 2456variable. 2457 2458 2459Please be aware that the Makefiles assume you are using GNU make, so 2460for instance on NetBSD you might need to use "gmake" instead of 2461native "make". 2462 2463 2464If the system board that you have is not listed, then you will need 2465to port U-Boot to your hardware platform. To do this, follow these 2466steps: 2467 24681. Add a new configuration option for your board to the toplevel 2469 "Makefile" and to the "MAKEALL" script, using the existing 2470 entries as examples. Note that here and at many other places 2471 boards and other names are listed in alphabetical sort order. Please 2472 keep this order. 24732. Create a new directory to hold your board specific code. Add any 2474 files you need. In your board directory, you will need at least 2475 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 24763. Create a new configuration file "include/configs/<board>.h" for 2477 your board 24783. If you're porting U-Boot to a new CPU, then also create a new 2479 directory to hold your CPU specific code. Add any files you need. 24804. Run "make <board>_config" with your new name. 24815. Type "make", and you should get a working "u-boot.srec" file 2482 to be installed on your target system. 24836. Debug and solve any problems that might arise. 2484 [Of course, this last step is much harder than it sounds.] 2485 2486 2487Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2488============================================================== 2489 2490If you have modified U-Boot sources (for instance added a new board 2491or support for new devices, a new CPU, etc.) you are expected to 2492provide feedback to the other developers. The feedback normally takes 2493the form of a "patch", i. e. a context diff against a certain (latest 2494official or latest in CVS) version of U-Boot sources. 2495 2496But before you submit such a patch, please verify that your modifi- 2497cation did not break existing code. At least make sure that *ALL* of 2498the supported boards compile WITHOUT ANY compiler warnings. To do so, 2499just run the "MAKEALL" script, which will configure and build U-Boot 2500for ALL supported system. Be warned, this will take a while. You can 2501select which (cross) compiler to use by passing a `CROSS_COMPILE' 2502environment variable to the script, i. e. to use the cross tools from 2503MontaVista's Hard Hat Linux you can type 2504 2505 CROSS_COMPILE=ppc_8xx- MAKEALL 2506 2507or to build on a native PowerPC system you can type 2508 2509 CROSS_COMPILE=' ' MAKEALL 2510 2511When using the MAKEALL script, the default behaviour is to build U-Boot 2512in the source directory. This location can be changed by setting the 2513BUILD_DIR environment variable. Also, for each target built, the MAKEALL 2514script saves two log files (<target>.ERR and <target>.MAKEALL) in the 2515<source dir>/LOG directory. This default location can be changed by 2516setting the MAKEALL_LOGDIR environment variable. For example: 2517 2518 export BUILD_DIR=/tmp/build 2519 export MAKEALL_LOGDIR=/tmp/log 2520 CROSS_COMPILE=ppc_8xx- MAKEALL 2521 2522With the above settings build objects are saved in the /tmp/build, log 2523files are saved in the /tmp/log and the source tree remains clean during 2524the whole build process. 2525 2526 2527See also "U-Boot Porting Guide" below. 2528 2529 2530Monitor Commands - Overview: 2531============================ 2532 2533go - start application at address 'addr' 2534run - run commands in an environment variable 2535bootm - boot application image from memory 2536bootp - boot image via network using BootP/TFTP protocol 2537tftpboot- boot image via network using TFTP protocol 2538 and env variables "ipaddr" and "serverip" 2539 (and eventually "gatewayip") 2540rarpboot- boot image via network using RARP/TFTP protocol 2541diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2542loads - load S-Record file over serial line 2543loadb - load binary file over serial line (kermit mode) 2544md - memory display 2545mm - memory modify (auto-incrementing) 2546nm - memory modify (constant address) 2547mw - memory write (fill) 2548cp - memory copy 2549cmp - memory compare 2550crc32 - checksum calculation 2551imd - i2c memory display 2552imm - i2c memory modify (auto-incrementing) 2553inm - i2c memory modify (constant address) 2554imw - i2c memory write (fill) 2555icrc32 - i2c checksum calculation 2556iprobe - probe to discover valid I2C chip addresses 2557iloop - infinite loop on address range 2558isdram - print SDRAM configuration information 2559sspi - SPI utility commands 2560base - print or set address offset 2561printenv- print environment variables 2562setenv - set environment variables 2563saveenv - save environment variables to persistent storage 2564protect - enable or disable FLASH write protection 2565erase - erase FLASH memory 2566flinfo - print FLASH memory information 2567bdinfo - print Board Info structure 2568iminfo - print header information for application image 2569coninfo - print console devices and informations 2570ide - IDE sub-system 2571loop - infinite loop on address range 2572loopw - infinite write loop on address range 2573mtest - simple RAM test 2574icache - enable or disable instruction cache 2575dcache - enable or disable data cache 2576reset - Perform RESET of the CPU 2577echo - echo args to console 2578version - print monitor version 2579help - print online help 2580? - alias for 'help' 2581 2582 2583Monitor Commands - Detailed Description: 2584======================================== 2585 2586TODO. 2587 2588For now: just type "help <command>". 2589 2590 2591Environment Variables: 2592====================== 2593 2594U-Boot supports user configuration using Environment Variables which 2595can be made persistent by saving to Flash memory. 2596 2597Environment Variables are set using "setenv", printed using 2598"printenv", and saved to Flash using "saveenv". Using "setenv" 2599without a value can be used to delete a variable from the 2600environment. As long as you don't save the environment you are 2601working with an in-memory copy. In case the Flash area containing the 2602environment is erased by accident, a default environment is provided. 2603 2604Some configuration options can be set using Environment Variables: 2605 2606 baudrate - see CONFIG_BAUDRATE 2607 2608 bootdelay - see CONFIG_BOOTDELAY 2609 2610 bootcmd - see CONFIG_BOOTCOMMAND 2611 2612 bootargs - Boot arguments when booting an RTOS image 2613 2614 bootfile - Name of the image to load with TFTP 2615 2616 autoload - if set to "no" (any string beginning with 'n'), 2617 "bootp" will just load perform a lookup of the 2618 configuration from the BOOTP server, but not try to 2619 load any image using TFTP 2620 2621 autostart - if set to "yes", an image loaded using the "bootp", 2622 "rarpboot", "tftpboot" or "diskboot" commands will 2623 be automatically started (by internally calling 2624 "bootm") 2625 2626 If set to "no", a standalone image passed to the 2627 "bootm" command will be copied to the load address 2628 (and eventually uncompressed), but NOT be started. 2629 This can be used to load and uncompress arbitrary 2630 data. 2631 2632 i2cfast - (PPC405GP|PPC405EP only) 2633 if set to 'y' configures Linux I2C driver for fast 2634 mode (400kHZ). This environment variable is used in 2635 initialization code. So, for changes to be effective 2636 it must be saved and board must be reset. 2637 2638 initrd_high - restrict positioning of initrd images: 2639 If this variable is not set, initrd images will be 2640 copied to the highest possible address in RAM; this 2641 is usually what you want since it allows for 2642 maximum initrd size. If for some reason you want to 2643 make sure that the initrd image is loaded below the 2644 CFG_BOOTMAPSZ limit, you can set this environment 2645 variable to a value of "no" or "off" or "0". 2646 Alternatively, you can set it to a maximum upper 2647 address to use (U-Boot will still check that it 2648 does not overwrite the U-Boot stack and data). 2649 2650 For instance, when you have a system with 16 MB 2651 RAM, and want to reserve 4 MB from use by Linux, 2652 you can do this by adding "mem=12M" to the value of 2653 the "bootargs" variable. However, now you must make 2654 sure that the initrd image is placed in the first 2655 12 MB as well - this can be done with 2656 2657 setenv initrd_high 00c00000 2658 2659 If you set initrd_high to 0xFFFFFFFF, this is an 2660 indication to U-Boot that all addresses are legal 2661 for the Linux kernel, including addresses in flash 2662 memory. In this case U-Boot will NOT COPY the 2663 ramdisk at all. This may be useful to reduce the 2664 boot time on your system, but requires that this 2665 feature is supported by your Linux kernel. 2666 2667 ipaddr - IP address; needed for tftpboot command 2668 2669 loadaddr - Default load address for commands like "bootp", 2670 "rarpboot", "tftpboot", "loadb" or "diskboot" 2671 2672 loads_echo - see CONFIG_LOADS_ECHO 2673 2674 serverip - TFTP server IP address; needed for tftpboot command 2675 2676 bootretry - see CONFIG_BOOT_RETRY_TIME 2677 2678 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 2679 2680 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 2681 2682 ethprime - When CONFIG_NET_MULTI is enabled controls which 2683 interface is used first. 2684 2685 ethact - When CONFIG_NET_MULTI is enabled controls which 2686 interface is currently active. For example you 2687 can do the following 2688 2689 => setenv ethact FEC ETHERNET 2690 => ping 192.168.0.1 # traffic sent on FEC ETHERNET 2691 => setenv ethact SCC ETHERNET 2692 => ping 10.0.0.1 # traffic sent on SCC ETHERNET 2693 2694 netretry - When set to "no" each network operation will 2695 either succeed or fail without retrying. 2696 When set to "once" the network operation will 2697 fail when all the available network interfaces 2698 are tried once without success. 2699 Useful on scripts which control the retry operation 2700 themselves. 2701 2702 tftpsrcport - If this is set, the value is used for TFTP's 2703 UDP source port. 2704 2705 tftpdstport - If this is set, the value is used for TFTP's UDP 2706 destination port instead of the Well Know Port 69. 2707 2708 vlan - When set to a value < 4095 the traffic over 2709 ethernet is encapsulated/received over 802.1q 2710 VLAN tagged frames. 2711 2712The following environment variables may be used and automatically 2713updated by the network boot commands ("bootp" and "rarpboot"), 2714depending the information provided by your boot server: 2715 2716 bootfile - see above 2717 dnsip - IP address of your Domain Name Server 2718 dnsip2 - IP address of your secondary Domain Name Server 2719 gatewayip - IP address of the Gateway (Router) to use 2720 hostname - Target hostname 2721 ipaddr - see above 2722 netmask - Subnet Mask 2723 rootpath - Pathname of the root filesystem on the NFS server 2724 serverip - see above 2725 2726 2727There are two special Environment Variables: 2728 2729 serial# - contains hardware identification information such 2730 as type string and/or serial number 2731 ethaddr - Ethernet address 2732 2733These variables can be set only once (usually during manufacturing of 2734the board). U-Boot refuses to delete or overwrite these variables 2735once they have been set once. 2736 2737 2738Further special Environment Variables: 2739 2740 ver - Contains the U-Boot version string as printed 2741 with the "version" command. This variable is 2742 readonly (see CONFIG_VERSION_VARIABLE). 2743 2744 2745Please note that changes to some configuration parameters may take 2746only effect after the next boot (yes, that's just like Windoze :-). 2747 2748 2749Command Line Parsing: 2750===================== 2751 2752There are two different command line parsers available with U-Boot: 2753the old "simple" one, and the much more powerful "hush" shell: 2754 2755Old, simple command line parser: 2756-------------------------------- 2757 2758- supports environment variables (through setenv / saveenv commands) 2759- several commands on one line, separated by ';' 2760- variable substitution using "... ${name} ..." syntax 2761- special characters ('$', ';') can be escaped by prefixing with '\', 2762 for example: 2763 setenv bootcmd bootm \${address} 2764- You can also escape text by enclosing in single apostrophes, for example: 2765 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' 2766 2767Hush shell: 2768----------- 2769 2770- similar to Bourne shell, with control structures like 2771 if...then...else...fi, for...do...done; while...do...done, 2772 until...do...done, ... 2773- supports environment ("global") variables (through setenv / saveenv 2774 commands) and local shell variables (through standard shell syntax 2775 "name=value"); only environment variables can be used with "run" 2776 command 2777 2778General rules: 2779-------------- 2780 2781(1) If a command line (or an environment variable executed by a "run" 2782 command) contains several commands separated by semicolon, and 2783 one of these commands fails, then the remaining commands will be 2784 executed anyway. 2785 2786(2) If you execute several variables with one call to run (i. e. 2787 calling run with a list af variables as arguments), any failing 2788 command will cause "run" to terminate, i. e. the remaining 2789 variables are not executed. 2790 2791Note for Redundant Ethernet Interfaces: 2792======================================= 2793 2794Some boards come with redundant ethernet interfaces; U-Boot supports 2795such configurations and is capable of automatic selection of a 2796"working" interface when needed. MAC assignment works as follows: 2797 2798Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2799MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2800"eth1addr" (=>eth1), "eth2addr", ... 2801 2802If the network interface stores some valid MAC address (for instance 2803in SROM), this is used as default address if there is NO correspon- 2804ding setting in the environment; if the corresponding environment 2805variable is set, this overrides the settings in the card; that means: 2806 2807o If the SROM has a valid MAC address, and there is no address in the 2808 environment, the SROM's address is used. 2809 2810o If there is no valid address in the SROM, and a definition in the 2811 environment exists, then the value from the environment variable is 2812 used. 2813 2814o If both the SROM and the environment contain a MAC address, and 2815 both addresses are the same, this MAC address is used. 2816 2817o If both the SROM and the environment contain a MAC address, and the 2818 addresses differ, the value from the environment is used and a 2819 warning is printed. 2820 2821o If neither SROM nor the environment contain a MAC address, an error 2822 is raised. 2823 2824 2825Image Formats: 2826============== 2827 2828The "boot" commands of this monitor operate on "image" files which 2829can be basicly anything, preceeded by a special header; see the 2830definitions in include/image.h for details; basicly, the header 2831defines the following image properties: 2832 2833* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2834 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2835 LynxOS, pSOS, QNX, RTEMS, ARTOS; 2836 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS). 2837* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86, 2838 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2839 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC). 2840* Compression Type (uncompressed, gzip, bzip2) 2841* Load Address 2842* Entry Point 2843* Image Name 2844* Image Timestamp 2845 2846The header is marked by a special Magic Number, and both the header 2847and the data portions of the image are secured against corruption by 2848CRC32 checksums. 2849 2850 2851Linux Support: 2852============== 2853 2854Although U-Boot should support any OS or standalone application 2855easily, the main focus has always been on Linux during the design of 2856U-Boot. 2857 2858U-Boot includes many features that so far have been part of some 2859special "boot loader" code within the Linux kernel. Also, any 2860"initrd" images to be used are no longer part of one big Linux image; 2861instead, kernel and "initrd" are separate images. This implementation 2862serves several purposes: 2863 2864- the same features can be used for other OS or standalone 2865 applications (for instance: using compressed images to reduce the 2866 Flash memory footprint) 2867 2868- it becomes much easier to port new Linux kernel versions because 2869 lots of low-level, hardware dependent stuff are done by U-Boot 2870 2871- the same Linux kernel image can now be used with different "initrd" 2872 images; of course this also means that different kernel images can 2873 be run with the same "initrd". This makes testing easier (you don't 2874 have to build a new "zImage.initrd" Linux image when you just 2875 change a file in your "initrd"). Also, a field-upgrade of the 2876 software is easier now. 2877 2878 2879Linux HOWTO: 2880============ 2881 2882Porting Linux to U-Boot based systems: 2883--------------------------------------- 2884 2885U-Boot cannot save you from doing all the necessary modifications to 2886configure the Linux device drivers for use with your target hardware 2887(no, we don't intend to provide a full virtual machine interface to 2888Linux :-). 2889 2890But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). 2891 2892Just make sure your machine specific header file (for instance 2893include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2894Information structure as we define in include/u-boot.h, and make 2895sure that your definition of IMAP_ADDR uses the same value as your 2896U-Boot configuration in CFG_IMMR. 2897 2898 2899Configuring the Linux kernel: 2900----------------------------- 2901 2902No specific requirements for U-Boot. Make sure you have some root 2903device (initial ramdisk, NFS) for your target system. 2904 2905 2906Building a Linux Image: 2907----------------------- 2908 2909With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2910not used. If you use recent kernel source, a new build target 2911"uImage" will exist which automatically builds an image usable by 2912U-Boot. Most older kernels also have support for a "pImage" target, 2913which was introduced for our predecessor project PPCBoot and uses a 2914100% compatible format. 2915 2916Example: 2917 2918 make TQM850L_config 2919 make oldconfig 2920 make dep 2921 make uImage 2922 2923The "uImage" build target uses a special tool (in 'tools/mkimage') to 2924encapsulate a compressed Linux kernel image with header information, 2925CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2926 2927* build a standard "vmlinux" kernel image (in ELF binary format): 2928 2929* convert the kernel into a raw binary image: 2930 2931 ${CROSS_COMPILE}-objcopy -O binary \ 2932 -R .note -R .comment \ 2933 -S vmlinux linux.bin 2934 2935* compress the binary image: 2936 2937 gzip -9 linux.bin 2938 2939* package compressed binary image for U-Boot: 2940 2941 mkimage -A ppc -O linux -T kernel -C gzip \ 2942 -a 0 -e 0 -n "Linux Kernel Image" \ 2943 -d linux.bin.gz uImage 2944 2945 2946The "mkimage" tool can also be used to create ramdisk images for use 2947with U-Boot, either separated from the Linux kernel image, or 2948combined into one file. "mkimage" encapsulates the images with a 64 2949byte header containing information about target architecture, 2950operating system, image type, compression method, entry points, time 2951stamp, CRC32 checksums, etc. 2952 2953"mkimage" can be called in two ways: to verify existing images and 2954print the header information, or to build new images. 2955 2956In the first form (with "-l" option) mkimage lists the information 2957contained in the header of an existing U-Boot image; this includes 2958checksum verification: 2959 2960 tools/mkimage -l image 2961 -l ==> list image header information 2962 2963The second form (with "-d" option) is used to build a U-Boot image 2964from a "data file" which is used as image payload: 2965 2966 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 2967 -n name -d data_file image 2968 -A ==> set architecture to 'arch' 2969 -O ==> set operating system to 'os' 2970 -T ==> set image type to 'type' 2971 -C ==> set compression type 'comp' 2972 -a ==> set load address to 'addr' (hex) 2973 -e ==> set entry point to 'ep' (hex) 2974 -n ==> set image name to 'name' 2975 -d ==> use image data from 'datafile' 2976 2977Right now, all Linux kernels for PowerPC systems use the same load 2978address (0x00000000), but the entry point address depends on the 2979kernel version: 2980 2981- 2.2.x kernels have the entry point at 0x0000000C, 2982- 2.3.x and later kernels have the entry point at 0x00000000. 2983 2984So a typical call to build a U-Boot image would read: 2985 2986 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 2987 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 2988 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \ 2989 > examples/uImage.TQM850L 2990 Image Name: 2.4.4 kernel for TQM850L 2991 Created: Wed Jul 19 02:34:59 2000 2992 Image Type: PowerPC Linux Kernel Image (gzip compressed) 2993 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 2994 Load Address: 0x00000000 2995 Entry Point: 0x00000000 2996 2997To verify the contents of the image (or check for corruption): 2998 2999 -> tools/mkimage -l examples/uImage.TQM850L 3000 Image Name: 2.4.4 kernel for TQM850L 3001 Created: Wed Jul 19 02:34:59 2000 3002 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3003 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 3004 Load Address: 0x00000000 3005 Entry Point: 0x00000000 3006 3007NOTE: for embedded systems where boot time is critical you can trade 3008speed for memory and install an UNCOMPRESSED image instead: this 3009needs more space in Flash, but boots much faster since it does not 3010need to be uncompressed: 3011 3012 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz 3013 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 3014 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 3015 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \ 3016 > examples/uImage.TQM850L-uncompressed 3017 Image Name: 2.4.4 kernel for TQM850L 3018 Created: Wed Jul 19 02:34:59 2000 3019 Image Type: PowerPC Linux Kernel Image (uncompressed) 3020 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 3021 Load Address: 0x00000000 3022 Entry Point: 0x00000000 3023 3024 3025Similar you can build U-Boot images from a 'ramdisk.image.gz' file 3026when your kernel is intended to use an initial ramdisk: 3027 3028 -> tools/mkimage -n 'Simple Ramdisk Image' \ 3029 > -A ppc -O linux -T ramdisk -C gzip \ 3030 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 3031 Image Name: Simple Ramdisk Image 3032 Created: Wed Jan 12 14:01:50 2000 3033 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3034 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 3035 Load Address: 0x00000000 3036 Entry Point: 0x00000000 3037 3038 3039Installing a Linux Image: 3040------------------------- 3041 3042To downloading a U-Boot image over the serial (console) interface, 3043you must convert the image to S-Record format: 3044 3045 objcopy -I binary -O srec examples/image examples/image.srec 3046 3047The 'objcopy' does not understand the information in the U-Boot 3048image header, so the resulting S-Record file will be relative to 3049address 0x00000000. To load it to a given address, you need to 3050specify the target address as 'offset' parameter with the 'loads' 3051command. 3052 3053Example: install the image to address 0x40100000 (which on the 3054TQM8xxL is in the first Flash bank): 3055 3056 => erase 40100000 401FFFFF 3057 3058 .......... done 3059 Erased 8 sectors 3060 3061 => loads 40100000 3062 ## Ready for S-Record download ... 3063 ~>examples/image.srec 3064 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 3065 ... 3066 15989 15990 15991 15992 3067 [file transfer complete] 3068 [connected] 3069 ## Start Addr = 0x00000000 3070 3071 3072You can check the success of the download using the 'iminfo' command; 3073this includes a checksum verification so you can be sure no data 3074corruption happened: 3075 3076 => imi 40100000 3077 3078 ## Checking Image at 40100000 ... 3079 Image Name: 2.2.13 for initrd on TQM850L 3080 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3081 Data Size: 335725 Bytes = 327 kB = 0 MB 3082 Load Address: 00000000 3083 Entry Point: 0000000c 3084 Verifying Checksum ... OK 3085 3086 3087Boot Linux: 3088----------- 3089 3090The "bootm" command is used to boot an application that is stored in 3091memory (RAM or Flash). In case of a Linux kernel image, the contents 3092of the "bootargs" environment variable is passed to the kernel as 3093parameters. You can check and modify this variable using the 3094"printenv" and "setenv" commands: 3095 3096 3097 => printenv bootargs 3098 bootargs=root=/dev/ram 3099 3100 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3101 3102 => printenv bootargs 3103 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3104 3105 => bootm 40020000 3106 ## Booting Linux kernel at 40020000 ... 3107 Image Name: 2.2.13 for NFS on TQM850L 3108 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3109 Data Size: 381681 Bytes = 372 kB = 0 MB 3110 Load Address: 00000000 3111 Entry Point: 0000000c 3112 Verifying Checksum ... OK 3113 Uncompressing Kernel Image ... OK 3114 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 3115 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3116 time_init: decrementer frequency = 187500000/60 3117 Calibrating delay loop... 49.77 BogoMIPS 3118 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 3119 ... 3120 3121If you want to boot a Linux kernel with initial ram disk, you pass 3122the memory addresses of both the kernel and the initrd image (PPBCOOT 3123format!) to the "bootm" command: 3124 3125 => imi 40100000 40200000 3126 3127 ## Checking Image at 40100000 ... 3128 Image Name: 2.2.13 for initrd on TQM850L 3129 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3130 Data Size: 335725 Bytes = 327 kB = 0 MB 3131 Load Address: 00000000 3132 Entry Point: 0000000c 3133 Verifying Checksum ... OK 3134 3135 ## Checking Image at 40200000 ... 3136 Image Name: Simple Ramdisk Image 3137 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3138 Data Size: 566530 Bytes = 553 kB = 0 MB 3139 Load Address: 00000000 3140 Entry Point: 00000000 3141 Verifying Checksum ... OK 3142 3143 => bootm 40100000 40200000 3144 ## Booting Linux kernel at 40100000 ... 3145 Image Name: 2.2.13 for initrd on TQM850L 3146 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3147 Data Size: 335725 Bytes = 327 kB = 0 MB 3148 Load Address: 00000000 3149 Entry Point: 0000000c 3150 Verifying Checksum ... OK 3151 Uncompressing Kernel Image ... OK 3152 ## Loading RAMDisk Image at 40200000 ... 3153 Image Name: Simple Ramdisk Image 3154 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3155 Data Size: 566530 Bytes = 553 kB = 0 MB 3156 Load Address: 00000000 3157 Entry Point: 00000000 3158 Verifying Checksum ... OK 3159 Loading Ramdisk ... OK 3160 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 3161 Boot arguments: root=/dev/ram 3162 time_init: decrementer frequency = 187500000/60 3163 Calibrating delay loop... 49.77 BogoMIPS 3164 ... 3165 RAMDISK: Compressed image found at block 0 3166 VFS: Mounted root (ext2 filesystem). 3167 3168 bash# 3169 3170Boot Linux and pass a flat device tree: 3171----------- 3172 3173First, U-Boot must be compiled with the appropriate defines. See the section 3174titled "Linux Kernel Interface" above for a more in depth explanation. The 3175following is an example of how to start a kernel and pass an updated 3176flat device tree: 3177 3178=> print oftaddr 3179oftaddr=0x300000 3180=> print oft 3181oft=oftrees/mpc8540ads.dtb 3182=> tftp $oftaddr $oft 3183Speed: 1000, full duplex 3184Using TSEC0 device 3185TFTP from server 192.168.1.1; our IP address is 192.168.1.101 3186Filename 'oftrees/mpc8540ads.dtb'. 3187Load address: 0x300000 3188Loading: # 3189done 3190Bytes transferred = 4106 (100a hex) 3191=> tftp $loadaddr $bootfile 3192Speed: 1000, full duplex 3193Using TSEC0 device 3194TFTP from server 192.168.1.1; our IP address is 192.168.1.2 3195Filename 'uImage'. 3196Load address: 0x200000 3197Loading:############ 3198done 3199Bytes transferred = 1029407 (fb51f hex) 3200=> print loadaddr 3201loadaddr=200000 3202=> print oftaddr 3203oftaddr=0x300000 3204=> bootm $loadaddr - $oftaddr 3205## Booting image at 00200000 ... 3206 Image Name: Linux-2.6.17-dirty 3207 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3208 Data Size: 1029343 Bytes = 1005.2 kB 3209 Load Address: 00000000 3210 Entry Point: 00000000 3211 Verifying Checksum ... OK 3212 Uncompressing Kernel Image ... OK 3213Booting using flat device tree at 0x300000 3214Using MPC85xx ADS machine description 3215Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 3216[snip] 3217 3218 3219More About U-Boot Image Types: 3220------------------------------ 3221 3222U-Boot supports the following image types: 3223 3224 "Standalone Programs" are directly runnable in the environment 3225 provided by U-Boot; it is expected that (if they behave 3226 well) you can continue to work in U-Boot after return from 3227 the Standalone Program. 3228 "OS Kernel Images" are usually images of some Embedded OS which 3229 will take over control completely. Usually these programs 3230 will install their own set of exception handlers, device 3231 drivers, set up the MMU, etc. - this means, that you cannot 3232 expect to re-enter U-Boot except by resetting the CPU. 3233 "RAMDisk Images" are more or less just data blocks, and their 3234 parameters (address, size) are passed to an OS kernel that is 3235 being started. 3236 "Multi-File Images" contain several images, typically an OS 3237 (Linux) kernel image and one or more data images like 3238 RAMDisks. This construct is useful for instance when you want 3239 to boot over the network using BOOTP etc., where the boot 3240 server provides just a single image file, but you want to get 3241 for instance an OS kernel and a RAMDisk image. 3242 3243 "Multi-File Images" start with a list of image sizes, each 3244 image size (in bytes) specified by an "uint32_t" in network 3245 byte order. This list is terminated by an "(uint32_t)0". 3246 Immediately after the terminating 0 follow the images, one by 3247 one, all aligned on "uint32_t" boundaries (size rounded up to 3248 a multiple of 4 bytes). 3249 3250 "Firmware Images" are binary images containing firmware (like 3251 U-Boot or FPGA images) which usually will be programmed to 3252 flash memory. 3253 3254 "Script files" are command sequences that will be executed by 3255 U-Boot's command interpreter; this feature is especially 3256 useful when you configure U-Boot to use a real shell (hush) 3257 as command interpreter. 3258 3259 3260Standalone HOWTO: 3261================= 3262 3263One of the features of U-Boot is that you can dynamically load and 3264run "standalone" applications, which can use some resources of 3265U-Boot like console I/O functions or interrupt services. 3266 3267Two simple examples are included with the sources: 3268 3269"Hello World" Demo: 3270------------------- 3271 3272'examples/hello_world.c' contains a small "Hello World" Demo 3273application; it is automatically compiled when you build U-Boot. 3274It's configured to run at address 0x00040004, so you can play with it 3275like that: 3276 3277 => loads 3278 ## Ready for S-Record download ... 3279 ~>examples/hello_world.srec 3280 1 2 3 4 5 6 7 8 9 10 11 ... 3281 [file transfer complete] 3282 [connected] 3283 ## Start Addr = 0x00040004 3284 3285 => go 40004 Hello World! This is a test. 3286 ## Starting application at 0x00040004 ... 3287 Hello World 3288 argc = 7 3289 argv[0] = "40004" 3290 argv[1] = "Hello" 3291 argv[2] = "World!" 3292 argv[3] = "This" 3293 argv[4] = "is" 3294 argv[5] = "a" 3295 argv[6] = "test." 3296 argv[7] = "<NULL>" 3297 Hit any key to exit ... 3298 3299 ## Application terminated, rc = 0x0 3300 3301Another example, which demonstrates how to register a CPM interrupt 3302handler with the U-Boot code, can be found in 'examples/timer.c'. 3303Here, a CPM timer is set up to generate an interrupt every second. 3304The interrupt service routine is trivial, just printing a '.' 3305character, but this is just a demo program. The application can be 3306controlled by the following keys: 3307 3308 ? - print current values og the CPM Timer registers 3309 b - enable interrupts and start timer 3310 e - stop timer and disable interrupts 3311 q - quit application 3312 3313 => loads 3314 ## Ready for S-Record download ... 3315 ~>examples/timer.srec 3316 1 2 3 4 5 6 7 8 9 10 11 ... 3317 [file transfer complete] 3318 [connected] 3319 ## Start Addr = 0x00040004 3320 3321 => go 40004 3322 ## Starting application at 0x00040004 ... 3323 TIMERS=0xfff00980 3324 Using timer 1 3325 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 3326 3327Hit 'b': 3328 [q, b, e, ?] Set interval 1000000 us 3329 Enabling timer 3330Hit '?': 3331 [q, b, e, ?] ........ 3332 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 3333Hit '?': 3334 [q, b, e, ?] . 3335 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 3336Hit '?': 3337 [q, b, e, ?] . 3338 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 3339Hit '?': 3340 [q, b, e, ?] . 3341 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 3342Hit 'e': 3343 [q, b, e, ?] ...Stopping timer 3344Hit 'q': 3345 [q, b, e, ?] ## Application terminated, rc = 0x0 3346 3347 3348Minicom warning: 3349================ 3350 3351Over time, many people have reported problems when trying to use the 3352"minicom" terminal emulation program for serial download. I (wd) 3353consider minicom to be broken, and recommend not to use it. Under 3354Unix, I recommend to use C-Kermit for general purpose use (and 3355especially for kermit binary protocol download ("loadb" command), and 3356use "cu" for S-Record download ("loads" command). 3357 3358Nevertheless, if you absolutely want to use it try adding this 3359configuration to your "File transfer protocols" section: 3360 3361 Name Program Name U/D FullScr IO-Red. Multi 3362 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 3363 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 3364 3365 3366NetBSD Notes: 3367============= 3368 3369Starting at version 0.9.2, U-Boot supports NetBSD both as host 3370(build U-Boot) and target system (boots NetBSD/mpc8xx). 3371 3372Building requires a cross environment; it is known to work on 3373NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 3374need gmake since the Makefiles are not compatible with BSD make). 3375Note that the cross-powerpc package does not install include files; 3376attempting to build U-Boot will fail because <machine/ansi.h> is 3377missing. This file has to be installed and patched manually: 3378 3379 # cd /usr/pkg/cross/powerpc-netbsd/include 3380 # mkdir powerpc 3381 # ln -s powerpc machine 3382 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 3383 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 3384 3385Native builds *don't* work due to incompatibilities between native 3386and U-Boot include files. 3387 3388Booting assumes that (the first part of) the image booted is a 3389stage-2 loader which in turn loads and then invokes the kernel 3390proper. Loader sources will eventually appear in the NetBSD source 3391tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 3392meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 3393 3394 3395Implementation Internals: 3396========================= 3397 3398The following is not intended to be a complete description of every 3399implementation detail. However, it should help to understand the 3400inner workings of U-Boot and make it easier to port it to custom 3401hardware. 3402 3403 3404Initial Stack, Global Data: 3405--------------------------- 3406 3407The implementation of U-Boot is complicated by the fact that U-Boot 3408starts running out of ROM (flash memory), usually without access to 3409system RAM (because the memory controller is not initialized yet). 3410This means that we don't have writable Data or BSS segments, and BSS 3411is not initialized as zero. To be able to get a C environment working 3412at all, we have to allocate at least a minimal stack. Implementation 3413options for this are defined and restricted by the CPU used: Some CPU 3414models provide on-chip memory (like the IMMR area on MPC8xx and 3415MPC826x processors), on others (parts of) the data cache can be 3416locked as (mis-) used as memory, etc. 3417 3418 Chris Hallinan posted a good summary of these issues to the 3419 u-boot-users mailing list: 3420 3421 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 3422 From: "Chris Hallinan" <clh@net1plus.com> 3423 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 3424 ... 3425 3426 Correct me if I'm wrong, folks, but the way I understand it 3427 is this: Using DCACHE as initial RAM for Stack, etc, does not 3428 require any physical RAM backing up the cache. The cleverness 3429 is that the cache is being used as a temporary supply of 3430 necessary storage before the SDRAM controller is setup. It's 3431 beyond the scope of this list to expain the details, but you 3432 can see how this works by studying the cache architecture and 3433 operation in the architecture and processor-specific manuals. 3434 3435 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3436 is another option for the system designer to use as an 3437 initial stack/ram area prior to SDRAM being available. Either 3438 option should work for you. Using CS 4 should be fine if your 3439 board designers haven't used it for something that would 3440 cause you grief during the initial boot! It is frequently not 3441 used. 3442 3443 CFG_INIT_RAM_ADDR should be somewhere that won't interfere 3444 with your processor/board/system design. The default value 3445 you will find in any recent u-boot distribution in 3446 walnut.h should work for you. I'd set it to a value larger 3447 than your SDRAM module. If you have a 64MB SDRAM module, set 3448 it above 400_0000. Just make sure your board has no resources 3449 that are supposed to respond to that address! That code in 3450 start.S has been around a while and should work as is when 3451 you get the config right. 3452 3453 -Chris Hallinan 3454 DS4.COM, Inc. 3455 3456It is essential to remember this, since it has some impact on the C 3457code for the initialization procedures: 3458 3459* Initialized global data (data segment) is read-only. Do not attempt 3460 to write it. 3461 3462* Do not use any unitialized global data (or implicitely initialized 3463 as zero data - BSS segment) at all - this is undefined, initiali- 3464 zation is performed later (when relocating to RAM). 3465 3466* Stack space is very limited. Avoid big data buffers or things like 3467 that. 3468 3469Having only the stack as writable memory limits means we cannot use 3470normal global data to share information beween the code. But it 3471turned out that the implementation of U-Boot can be greatly 3472simplified by making a global data structure (gd_t) available to all 3473functions. We could pass a pointer to this data as argument to _all_ 3474functions, but this would bloat the code. Instead we use a feature of 3475the GCC compiler (Global Register Variables) to share the data: we 3476place a pointer (gd) to the global data into a register which we 3477reserve for this purpose. 3478 3479When choosing a register for such a purpose we are restricted by the 3480relevant (E)ABI specifications for the current architecture, and by 3481GCC's implementation. 3482 3483For PowerPC, the following registers have specific use: 3484 R1: stack pointer 3485 R2: TOC pointer 3486 R3-R4: parameter passing and return values 3487 R5-R10: parameter passing 3488 R13: small data area pointer 3489 R30: GOT pointer 3490 R31: frame pointer 3491 3492 (U-Boot also uses R14 as internal GOT pointer.) 3493 3494 ==> U-Boot will use R29 to hold a pointer to the global data 3495 3496 Note: on PPC, we could use a static initializer (since the 3497 address of the global data structure is known at compile time), 3498 but it turned out that reserving a register results in somewhat 3499 smaller code - although the code savings are not that big (on 3500 average for all boards 752 bytes for the whole U-Boot image, 3501 624 text + 127 data). 3502 3503On ARM, the following registers are used: 3504 3505 R0: function argument word/integer result 3506 R1-R3: function argument word 3507 R9: GOT pointer 3508 R10: stack limit (used only if stack checking if enabled) 3509 R11: argument (frame) pointer 3510 R12: temporary workspace 3511 R13: stack pointer 3512 R14: link register 3513 R15: program counter 3514 3515 ==> U-Boot will use R8 to hold a pointer to the global data 3516 3517NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 3518or current versions of GCC may "optimize" the code too much. 3519 3520Memory Management: 3521------------------ 3522 3523U-Boot runs in system state and uses physical addresses, i.e. the 3524MMU is not used either for address mapping nor for memory protection. 3525 3526The available memory is mapped to fixed addresses using the memory 3527controller. In this process, a contiguous block is formed for each 3528memory type (Flash, SDRAM, SRAM), even when it consists of several 3529physical memory banks. 3530 3531U-Boot is installed in the first 128 kB of the first Flash bank (on 3532TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3533booting and sizing and initializing DRAM, the code relocates itself 3534to the upper end of DRAM. Immediately below the U-Boot code some 3535memory is reserved for use by malloc() [see CFG_MALLOC_LEN 3536configuration setting]. Below that, a structure with global Board 3537Info data is placed, followed by the stack (growing downward). 3538 3539Additionally, some exception handler code is copied to the low 8 kB 3540of DRAM (0x00000000 ... 0x00001FFF). 3541 3542So a typical memory configuration with 16 MB of DRAM could look like 3543this: 3544 3545 0x0000 0000 Exception Vector code 3546 : 3547 0x0000 1FFF 3548 0x0000 2000 Free for Application Use 3549 : 3550 : 3551 3552 : 3553 : 3554 0x00FB FF20 Monitor Stack (Growing downward) 3555 0x00FB FFAC Board Info Data and permanent copy of global data 3556 0x00FC 0000 Malloc Arena 3557 : 3558 0x00FD FFFF 3559 0x00FE 0000 RAM Copy of Monitor Code 3560 ... eventually: LCD or video framebuffer 3561 ... eventually: pRAM (Protected RAM - unchanged by reset) 3562 0x00FF FFFF [End of RAM] 3563 3564 3565System Initialization: 3566---------------------- 3567 3568In the reset configuration, U-Boot starts at the reset entry point 3569(on most PowerPC systens at address 0x00000100). Because of the reset 3570configuration for CS0# this is a mirror of the onboard Flash memory. 3571To be able to re-map memory U-Boot then jumps to its link address. 3572To be able to implement the initialization code in C, a (small!) 3573initial stack is set up in the internal Dual Ported RAM (in case CPUs 3574which provide such a feature like MPC8xx or MPC8260), or in a locked 3575part of the data cache. After that, U-Boot initializes the CPU core, 3576the caches and the SIU. 3577 3578Next, all (potentially) available memory banks are mapped using a 3579preliminary mapping. For example, we put them on 512 MB boundaries 3580(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3581on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3582programmed for SDRAM access. Using the temporary configuration, a 3583simple memory test is run that determines the size of the SDRAM 3584banks. 3585 3586When there is more than one SDRAM bank, and the banks are of 3587different size, the largest is mapped first. For equal size, the first 3588bank (CS2#) is mapped first. The first mapping is always for address 35890x00000000, with any additional banks following immediately to create 3590contiguous memory starting from 0. 3591 3592Then, the monitor installs itself at the upper end of the SDRAM area 3593and allocates memory for use by malloc() and for the global Board 3594Info data; also, the exception vector code is copied to the low RAM 3595pages, and the final stack is set up. 3596 3597Only after this relocation will you have a "normal" C environment; 3598until that you are restricted in several ways, mostly because you are 3599running from ROM, and because the code will have to be relocated to a 3600new address in RAM. 3601 3602 3603U-Boot Porting Guide: 3604---------------------- 3605 3606[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3607list, October 2002] 3608 3609 3610int main (int argc, char *argv[]) 3611{ 3612 sighandler_t no_more_time; 3613 3614 signal (SIGALRM, no_more_time); 3615 alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); 3616 3617 if (available_money > available_manpower) { 3618 pay consultant to port U-Boot; 3619 return 0; 3620 } 3621 3622 Download latest U-Boot source; 3623 3624 Subscribe to u-boot-users mailing list; 3625 3626 if (clueless) { 3627 email ("Hi, I am new to U-Boot, how do I get started?"); 3628 } 3629 3630 while (learning) { 3631 Read the README file in the top level directory; 3632 Read http://www.denx.de/twiki/bin/view/DULG/Manual ; 3633 Read the source, Luke; 3634 } 3635 3636 if (available_money > toLocalCurrency ($2500)) { 3637 Buy a BDI2000; 3638 } else { 3639 Add a lot of aggravation and time; 3640 } 3641 3642 Create your own board support subdirectory; 3643 3644 Create your own board config file; 3645 3646 while (!running) { 3647 do { 3648 Add / modify source code; 3649 } until (compiles); 3650 Debug; 3651 if (clueless) 3652 email ("Hi, I am having problems..."); 3653 } 3654 Send patch file to Wolfgang; 3655 3656 return 0; 3657} 3658 3659void no_more_time (int sig) 3660{ 3661 hire_a_guru(); 3662} 3663 3664 3665Coding Standards: 3666----------------- 3667 3668All contributions to U-Boot should conform to the Linux kernel 3669coding style; see the file "Documentation/CodingStyle" and the script 3670"scripts/Lindent" in your Linux kernel source directory. In sources 3671originating from U-Boot a style corresponding to "Lindent -pcs" (adding 3672spaces before parameters to function calls) is actually used. 3673 3674Source files originating from a different project (for example the 3675MTD subsystem) are generally exempt from these guidelines and are not 3676reformated to ease subsequent migration to newer versions of those 3677sources. 3678 3679Please note that U-Boot is implemented in C (and to some small parts in 3680Assembler); no C++ is used, so please do not use C++ style comments (//) 3681in your code. 3682 3683Please also stick to the following formatting rules: 3684- remove any trailing white space 3685- use TAB characters for indentation, not spaces 3686- make sure NOT to use DOS '\r\n' line feeds 3687- do not add more than 2 empty lines to source files 3688- do not add trailing empty lines to source files 3689 3690Submissions which do not conform to the standards may be returned 3691with a request to reformat the changes. 3692 3693 3694Submitting Patches: 3695------------------- 3696 3697Since the number of patches for U-Boot is growing, we need to 3698establish some rules. Submissions which do not conform to these rules 3699may be rejected, even when they contain important and valuable stuff. 3700 3701Patches shall be sent to the u-boot-users mailing list. 3702 3703When you send a patch, please include the following information with 3704it: 3705 3706* For bug fixes: a description of the bug and how your patch fixes 3707 this bug. Please try to include a way of demonstrating that the 3708 patch actually fixes something. 3709 3710* For new features: a description of the feature and your 3711 implementation. 3712 3713* A CHANGELOG entry as plaintext (separate from the patch) 3714 3715* For major contributions, your entry to the CREDITS file 3716 3717* When you add support for a new board, don't forget to add this 3718 board to the MAKEALL script, too. 3719 3720* If your patch adds new configuration options, don't forget to 3721 document these in the README file. 3722 3723* The patch itself. If you are accessing the CVS repository use "cvs 3724 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your 3725 version of diff does not support these options, then get the latest 3726 version of GNU diff. 3727 3728 The current directory when running this command shall be the top 3729 level directory of the U-Boot source tree, or it's parent directory 3730 (i. e. please make sure that your patch includes sufficient 3731 directory information for the affected files). 3732 3733 We accept patches as plain text, MIME attachments or as uuencoded 3734 gzipped text. 3735 3736* If one logical set of modifications affects or creates several 3737 files, all these changes shall be submitted in a SINGLE patch file. 3738 3739* Changesets that contain different, unrelated modifications shall be 3740 submitted as SEPARATE patches, one patch per changeset. 3741 3742 3743Notes: 3744 3745* Before sending the patch, run the MAKEALL script on your patched 3746 source tree and make sure that no errors or warnings are reported 3747 for any of the boards. 3748 3749* Keep your modifications to the necessary minimum: A patch 3750 containing several unrelated changes or arbitrary reformats will be 3751 returned with a request to re-formatting / split it. 3752 3753* If you modify existing code, make sure that your new code does not 3754 add to the memory footprint of the code ;-) Small is beautiful! 3755 When adding new features, these should compile conditionally only 3756 (using #ifdef), and the resulting code with the new feature 3757 disabled must not need more memory than the old code without your 3758 modification. 3759 3760* Remember that there is a size limit of 40 kB per message on the 3761 u-boot-users mailing list. Compression may help. 3762