diff options
| author | wdenk <wdenk> | 2002-11-03 00:24:07 +0000 |
|---|---|---|
| committer | wdenk <wdenk> | 2002-11-03 00:24:07 +0000 |
| commit | c609719b8d1b2dca590e0ed499016d041203e403 (patch) | |
| tree | 7ea1755d80903ff972f312a249eb856061d40e15 /README | |
| parent | 5b1d713721c3ea02549940133f09236783dda1f9 (diff) | |
Initial revision
Diffstat (limited to 'README')
| -rw-r--r-- | README | 2663 |
1 files changed, 2663 insertions, 0 deletions
diff --git a/README b/README new file mode 100644 index 00000000000..30ff772c6d8 --- /dev/null +++ b/README @@ -0,0 +1,2663 @@ +# +# (C) Copyright 2000 - 2002 +# Wolfgang Denk, DENX Software Engineering, wd@denx.de. +# +# See file CREDITS for list of people who contributed to this +# project. +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License as +# published by the Free Software Foundation; either version 2 of +# the License, or (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, +# MA 02111-1307 USA +# + +Summary: +======== + +This directory contains the source code for U-Boot, a monitor for +Embedded PowerPC boards, which can be installed in a boot ROM and +used to test the hardware or download and run application code. + +The development of U-Boot is closely related to Linux: some parts of +the source code originate in the Linux source tree, we still have +some header files in common, and special provision has been made to +support booting of Linux images. + +Some attention has been paid to make this software easily +configurable and extendable. For instance, all monitor commands are +implemented with the same call interface, so that it's very easy to +add new commands. Also, instead of permanently adding rarely used +code (for instance hardware test utilities) to the monitor, you can +load and run it dynamically. + + +Status: +======= + +In general, all boards for which a configuration option exists in the +Makefile have been tested to some extent and can be considered +"working". In fact, many of them are used in production systems. + +In case of problems see the CHANGELOG and CREDITS files to find out +who contributed the specific port. + +Exception from this rule: the port to the Sandpoint 8240 has not been +completed yet. + + +Where to get help: +================== + +In case you have questions about, problems with or contributions for +U-Boot you should send a message to the U-Boot mailing list at +<u-boot-users@lists.sourceforge.net>. There is also an archive of +previous traffic on the mailing list - please search the archive +before asking FAQ's. Please see +http://lists.sourceforge.net/lists/listinfo/u-boot-users/ + + +Where we come from: +=================== + +- start from 8xxrom sources +- clean up code +- make it easier to add custom boards +- make it possible to add other [PowerPC] CPUs +- extend functions, especially: + * Provide extended interface to Linux boot loader + * S-Record download + * network boot + * PCMCIA / CompactFLash / ATA disk / SCSI ... boot +- add other CPU families (starting with ARM) + + +Directory Hierarchy: +==================== + +- board Board dependend files +- common Misc architecture independend functions +- cpu CPU specific files +- disk Code for disk drive partition handling +- doc Documentation (don't expect too much) +- drivers Common used device drivers +- dtt Digital Thermometer and Thermostat drivers +- examples Example code for standalone applications, etc. +- include Header Files +- disk Harddisk interface code +- net Networking code +- ppc Files generic to PowerPC architecture +- post Power On Self Test +- post/arch Symlink to architecture specific Power On Self Test +- post/arch-ppc PowerPC architecture specific Power On Self Test +- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test +- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test +- rtc Real Time Clock drivers +- tools Tools to build S-Record or U-Boot images, etc. + +- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs +- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs +- cpu/mpc824x Files specific to Motorola MPC824x CPUs +- cpu/mpc8260 Files specific to Motorola MPC8260 CPU +- cpu/ppc4xx Files specific to IBM 4xx CPUs + +- board/RPXClassic + Files specific to RPXClassic boards +- board/RPXlite Files specific to RPXlite boards +- board/c2mon Files specific to c2mon boards +- board/cogent Files specific to Cogent boards + (need further configuration) + Files specific to CPCIISER4 boards +- board/cpu86 Files specific to CPU86 boards +- board/cray/ Files specific to boards manufactured by Cray +- board/cray/L1 Files specific to L1 boards +- board/cu824 Files specific to CU824 boards +- board/ebony Files specific to IBM Ebony board +- board/eric Files specific to ERIC boards +- board/esd/ Files specific to boards manufactured by ESD +- board/esd/adciop Files specific to ADCIOP boards +- board/esd/ar405 Files specific to AR405 boards +- board/esd/canbt Files specific to CANBT boards +- board/esd/cpci405 Files specific to CPCI405 boards +- board/esd/cpciiser4 Files specific to CPCIISER4 boards +- board/esd/common Common files for ESD boards +- board/esd/dasa_sim Files specific to DASA_SIM boards +- board/esd/du405 Files specific to DU405 boards +- board/esd/ocrtc Files specific to OCRTC boards +- board/esd/pci405 Files specific to PCI405 boards +- board/esteem192e + Files specific to ESTEEM192E boards +- board/etx094 Files specific to ETX_094 boards +- board/evb64260 + Files specific to EVB64260 boards +- board/fads Files specific to FADS boards +- board/flagadm Files specific to FLAGADM boards +- board/gen860t Files specific to GEN860T boards +- board/genietv Files specific to GENIETV boards +- board/gth Files specific to GTH boards +- board/hermes Files specific to HERMES boards +- board/hymod Files specific to HYMOD boards +- board/icu862 Files specific to ICU862 boards +- board/ip860 Files specific to IP860 boards +- board/iphase4539 + Files specific to Interphase4539 boards +- board/ivm Files specific to IVMS8/IVML24 boards +- board/lantec Files specific to LANTEC boards +- board/lwmon Files specific to LWMON boards +- board/mbx8xx Files specific to MBX boards +- board/mpc8260ads + Files specific to MMPC8260ADS boards +- board/mpl/ Files specific to boards manufactured by MPL +- board/mpl/common Common files for MPL boards +- board/mpl/pip405 Files specific to PIP405 boards +- board/mpl/mip405 Files specific to MIP405 boards +- board/musenki Files specific to MUSEKNI boards +- board/mvs1 Files specific to MVS1 boards +- board/nx823 Files specific to NX823 boards +- board/oxc Files specific to OXC boards +- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards +- board/pm826 Files specific to PM826 boards +- board/ppmc8260 + Files specific to PPMC8260 boards +- board/rpxsuper + Files specific to RPXsuper boards +- board/rsdproto + Files specific to RSDproto boards +- board/sandpoint + Files specific to Sandpoint boards +- board/sbc8260 Files specific to SBC8260 boards +- board/sacsng Files specific to SACSng boards +- board/siemens Files specific to boards manufactured by Siemens AG +- board/siemens/CCM Files specific to CCM boards +- board/siemens/IAD210 Files specific to IAD210 boards +- board/siemens/SCM Files specific to SCM boards +- board/siemens/pcu_e Files specific to PCU_E boards +- board/sixnet Files specific to SIXNET boards +- board/spd8xx Files specific to SPD8xxTS boards +- board/tqm8260 Files specific to TQM8260 boards +- board/tqm8xx Files specific to TQM8xxL boards +- board/w7o Files specific to W7O boards +- board/walnut405 + Files specific to Walnut405 boards +- board/westel/ Files specific to boards manufactured by Westel Wireless +- board/westel/amx860 Files specific to AMX860 boards +- board/utx8245 Files specific to UTX8245 boards + +Software Configuration: +======================= + +Configuration is usually done using C preprocessor defines; the +rationale behind that is to avoid dead code whenever possible. + +There are two classes of configuration variables: + +* Configuration _OPTIONS_: + These are selectable by the user and have names beginning with + "CONFIG_". + +* Configuration _SETTINGS_: + These depend on the hardware etc. and should not be meddled with if + you don't know what you're doing; they have names beginning with + "CFG_". + +Later we will add a configuration tool - probably similar to or even +identical to what's used for the Linux kernel. Right now, we have to +do the configuration by hand, which means creating some symbolic +links and editing some configuration files. We use the TQM8xxL boards +as an example here. + + +Selection of Processor Architecture and Board Type: +--------------------------------------------------- + +For all supported boards there are ready-to-use default +configurations available; just type "make <board_name>_config". + +Example: For a TQM823L module type: + + cd u-boot + make TQM823L_config + +For the Cogent platform, you need to specify the cpu type as well; +e.g. "make cogent_mpc8xx_config". And also configure the cogent +directory according to the instructions in cogent/README. + + +Configuration Options: +---------------------- + +Configuration depends on the combination of board and CPU type; all +such information is kept in a configuration file +"include/configs/<board_name>.h". + +Example: For a TQM823L module, all configuration settings are in +"include/configs/TQM823L.h". + + +The following options need to be configured: + +- CPU Type: Define exactly one of + + PowerPC based CPUs: + ------------------- + CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860 + or CONFIG_MPC824X, CONFIG_MPC8260 + or CONFIG_IOP480 + or CONFIG_405GP + or CONFIG_440 + or CONFIG_MPC74xx + + ARM based CPUs: + --------------- + CONFIG_SA1110 + CONFIG_ARM7 + CONFIG_PXA250 + + +- Board Type: Define exactly one of + + PowerPC based boards: + --------------------- + + CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper, + CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850, + CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS, + CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T, + CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240, + CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245, + CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L, + CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L, + CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L, + CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L, + CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260, + CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech, + CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245, + CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC, + CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG, + CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405, + CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA, + CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon, + CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260, + CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx, + CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260, + CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260, + CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes, + CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod, + CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon, + CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e, + CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260, + CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto, + CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260, + CONFIG_EBONY, CONFIG_sacsng + + ARM based boards: + ----------------- + + CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312, + CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK, + CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410, + CONFIG_TRAB + + +- CPU Module Type: (if CONFIG_COGENT is defined) + Define exactly one of + CONFIG_CMA286_60_OLD +--- FIXME --- not tested yet: + CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P, + CONFIG_CMA287_23, CONFIG_CMA287_50 + +- Motherboard Type: (if CONFIG_COGENT is defined) + Define exactly one of + CONFIG_CMA101, CONFIG_CMA102 + +- Motherboard I/O Modules: (if CONFIG_COGENT is defined) + Define one or more of + CONFIG_CMA302 + +- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined) + Define one or more of + CONFIG_LCD_HEARTBEAT - update a character position on + the lcd display every second with + a "rotator" |\-/|\-/ + +- MPC824X Family Member (if CONFIG_MPC824X is defined) + Define exactly one of + CONFIG_MPC8240, CONFIG_MPC8245 + +- 8xx CPU Options: (if using an 8xx cpu) + Define one or more of + CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g. + no 32KHz reference PIT/RTC clock + +- Clock Interface: + CONFIG_CLOCKS_IN_MHZ + + U-Boot stores all clock information in Hz + internally. For binary compatibility with older Linux + kernels (which expect the clocks passed in the + bd_info data to be in MHz) the environment variable + "clocks_in_mhz" can be defined so that U-Boot + converts clock data to MHZ before passing it to the + Linux kernel. + + When CONFIG_CLOCKS_IN_MHZ is defined, a definition of + "clocks_in_mhz=1" is automatically included in the + default environment. + +- Console Interface: + Depending on board, define exactly one serial port + (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2, + CONFIG_8xx_CONS_SCC1, ...), or switch off the serial + console by defining CONFIG_8xx_CONS_NONE + + Note: if CONFIG_8xx_CONS_NONE is defined, the serial + port routines must be defined elsewhere + (i.e. serial_init(), serial_getc(), ...) + + CONFIG_CFB_CONSOLE + Enables console device for a color framebuffer. Needs following + defines (cf. smiLynxEM, i8042, board/eltec/bab7xx) + VIDEO_FB_LITTLE_ENDIAN graphic memory organisation + (default big endian) + VIDEO_HW_RECTFILL graphic chip supports + rectangle fill + (cf. smiLynxEM) + VIDEO_HW_BITBLT graphic chip supports + bit-blit (cf. smiLynxEM) + VIDEO_VISIBLE_COLS visible pixel columns + (cols=pitch) + VIDEO_VISIBLE_ROWS visible pixel rows + VIDEO_PIXEL_SIZE bytes per pixel + VIDEO_DATA_FORMAT graphic data format + (0-5, cf. cfb_console.c) + VIDEO_FB_ADRS framebuffer address + VIDEO_KBD_INIT_FCT keyboard int fct + (i.e. i8042_kbd_init()) + VIDEO_TSTC_FCT test char fct + (i.e. i8042_tstc) + VIDEO_GETC_FCT get char fct + (i.e. i8042_getc) + CONFIG_CONSOLE_CURSOR cursor drawing on/off + (requires blink timer + cf. i8042.c) + CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c) + CONFIG_CONSOLE_TIME display time/date info in + upper right corner + (requires CFG_CMD_DATE) + CONFIG_VIDEO_LOGO display Linux logo in + upper left corner + CONFIG_CONSOLE_EXTRA_INFO + addional board info beside + the logo + + When CONFIG_CFB_CONSOLE is defined, video console is + default i/o. Serial console can be forced with + environment 'console=serial'. + +- Console Baudrate: + CONFIG_BAUDRATE - in bps + Select one of the baudrates listed in + CFG_BAUDRATE_TABLE, see below. + +- Interrupt driven serial port input: + CONFIG_SERIAL_SOFTWARE_FIFO + + PPC405GP only. + Use an interrupt handler for receiving data on the + serial port. It also enables using hardware handshake + (RTS/CTS) and UART's built-in FIFO. Set the number of + bytes the interrupt driven input buffer should have. + + Set to 0 to disable this feature (this is the default). + This will also disable hardware handshake. + +- Boot Delay: CONFIG_BOOTDELAY - in seconds + Delay before automatically booting the default image; + set to -1 to disable autoboot. + + See doc/README.autoboot for these options that + work with CONFIG_BOOTDELAY. None are required. + CONFIG_BOOT_RETRY_TIME + CONFIG_BOOT_RETRY_MIN + CONFIG_AUTOBOOT_KEYED + CONFIG_AUTOBOOT_PROMPT + CONFIG_AUTOBOOT_DELAY_STR + CONFIG_AUTOBOOT_STOP_STR + CONFIG_AUTOBOOT_DELAY_STR2 + CONFIG_AUTOBOOT_STOP_STR2 + CONFIG_ZERO_BOOTDELAY_CHECK + CONFIG_RESET_TO_RETRY + +- Autoboot Command: + CONFIG_BOOTCOMMAND + Only needed when CONFIG_BOOTDELAY is enabled; + define a command string that is automatically executed + when no character is read on the console interface + within "Boot Delay" after reset. + + CONFIG_BOOTARGS + This can be used to pass arguments to the bootm + command. The value of CONFIG_BOOTARGS goes into the + environment value "bootargs". + + CONFIG_RAMBOOT and CONFIG_NFSBOOT + The value of these goes into the environment as + "ramboot" and "nfsboot" respectively, and can be used + as a convenience, when switching between booting from + ram and nfs. + +- Pre-Boot Commands: + CONFIG_PREBOOT + + When this option is #defined, the existence of the + environment variable "preboot" will be checked + immediately before starting the CONFIG_BOOTDELAY + countdown and/or running the auto-boot command resp. + entering interactive mode. + + This feature is especially useful when "preboot" is + automatically generated or modified. For an example + see the LWMON board specific code: here "preboot" is + modified when the user holds down a certain + combination of keys on the (special) keyboard when + booting the systems + +- Serial Download Echo Mode: + CONFIG_LOADS_ECHO + If defined to 1, all characters received during a + serial download (using the "loads" command) are + echoed back. This might be needed by some terminal + emulations (like "cu"), but may as well just take + time on others. This setting #define's the initial + value of the "loads_echo" environment variable. + +- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined) + CONFIG_KGDB_BAUDRATE + Select one of the baudrates listed in + CFG_BAUDRATE_TABLE, see below. + +- Monitor Functions: + CONFIG_COMMANDS + Most monitor functions can be selected (or + de-selected) by adjusting the definition of + CONFIG_COMMANDS; to select individual functions, + #define CONFIG_COMMANDS by "OR"ing any of the + following values: + + #define enables commands: + ------------------------- + CFG_CMD_ASKENV * ask for env variable + CFG_CMD_BDI bdinfo + CFG_CMD_BEDBUG Include BedBug Debugger + CFG_CMD_BOOTD bootd + CFG_CMD_CACHE icache, dcache + CFG_CMD_CONSOLE coninfo + CFG_CMD_DATE * support for RTC, date/time... + CFG_CMD_DHCP DHCP support + CFG_CMD_ECHO * echo arguments + CFG_CMD_EEPROM * EEPROM read/write support + CFG_CMD_ELF bootelf, bootvx + CFG_CMD_ENV saveenv + CFG_CMD_FDC * Floppy Disk Support + CFG_CMD_FLASH flinfo, erase, protect + CFG_CMD_FPGA FPGA device initialization support + CFG_CMD_I2C * I2C serial bus support + CFG_CMD_IDE * IDE harddisk support + CFG_CMD_IMI iminfo + CFG_CMD_IMMAP * IMMR dump support + CFG_CMD_IRQ * irqinfo + CFG_CMD_KGDB * kgdb + CFG_CMD_LOADB loadb + CFG_CMD_LOADS loads + CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, + loop, mtest + CFG_CMD_MII MII utility commands + CFG_CMD_NET bootp, tftpboot, rarpboot + CFG_CMD_PCI * pciinfo + CFG_CMD_PCMCIA * PCMCIA support + CFG_CMD_REGINFO * Register dump + CFG_CMD_RUN run command in env variable + CFG_CMD_SCSI * SCSI Support + CFG_CMD_SETGETDCR Support for DCR Register access (4xx only) + CFG_CMD_SPI * SPI serial bus support + CFG_CMD_USB * USB support + CFG_CMD_BSP * Board SPecific functions + ----------------------------------------------- + CFG_CMD_ALL all + + CFG_CMD_DFL Default configuration; at the moment + this is includes all commands, except + the ones marked with "*" in the list + above. + + If you don't define CONFIG_COMMANDS it defaults to + CFG_CMD_DFL in include/cmd_confdefs.h. A board can + override the default settings in the respective + include file. + + EXAMPLE: If you want all functions except of network + support you can write: + + #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET) + + + Note: Don't enable the "icache" and "dcache" commands + (configuration option CFG_CMD_CACHE) unless you know + what you (and your U-Boot users) are doing. Data + cache cannot be enabled on systems like the 8xx or + 8260 (where accesses to the IMMR region must be + uncached), and it cannot be disabled on all other + systems where we (mis-) use the data cache to hold an + initial stack and some data. + + + XXX - this list needs to get updated! + +- Watchdog: + CONFIG_WATCHDOG + If this variable is defined, it enables watchdog + support. There must support in the platform specific + code for a watchdog. For the 8xx and 8260 CPUs, the + SIU Watchdog feature is enabled in the SYPCR + register. + +- Real-Time Clock: + + When CFG_CMD_DATE is selected, the type of the RTC + has to be selected, too. Define exactly one of the + following options: + + CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx + CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC + CONFIG_RTC_MC146818 - use MC146818 RTC + CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC + +- Timestamp Support: + + When CONFIG_TIMESTAMP is selected, the timestamp + (date and time) of an image is printed by image + commands like bootm or iminfo. This option is + automatically enabled when you select CFG_CMD_DATE . + +- Partition Support: + CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION + and/or CONFIG_ISO_PARTITION + + If IDE or SCSI support is enabled (CFG_CMD_IDE or + CFG_CMD_SCSI) you must configure support for at least + one partition type as well. + +- IDE Reset method: + CONFIG_IDE_RESET_ROUTINE + + Set this to define that instead of a reset Pin, the + routine ide_set_reset(int idereset) will be used. + +- ATAPI Support: + CONFIG_ATAPI + + Set this to enable ATAPI support. + +- SCSI Support: + At the moment only there is only support for the + SYM53C8XX SCSI controller; define + CONFIG_SCSI_SYM53C8XX to enable it. + + CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and + CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID * + CFG_SCSI_MAX_LUN] can be adjusted to define the + maximum numbers of LUNs, SCSI ID's and target + devices. + CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz) + +- NETWORK Support (PCI): + CONFIG_EEPRO100 + Support for Intel 82557/82559/82559ER chips. + Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom + write routine for first time initialisation. + + CONFIG_TULIP + Support for Digital 2114x chips. + Optional CONFIG_TULIP_SELECT_MEDIA for board specific + modem chip initialisation (KS8761/QS6611). + + CONFIG_NATSEMI + Support for National dp83815 chips. + + CONFIG_NS8382X + Support for National dp8382[01] gigabit chips. + +- USB Support: + At the moment only the UHCI host controller is + supported (PIP405, MIP405); define + CONFIG_USB_UHCI to enable it. + define CONFIG_USB_KEYBOARD to enable the USB Keyboard + end define CONFIG_USB_STORAGE to enable the USB + storage devices. + Note: + Supported are USB Keyboards and USB Floppy drives + (TEAC FD-05PUB). + +- Keyboard Support: + CONFIG_ISA_KEYBOARD + + Define this to enable standard (PC-Style) keyboard + support + + CONFIG_I8042_KBD + Standard PC keyboard driver with US (is default) and + GERMAN key layout (switch via environment 'keymap=de') support. + Export function i8042_kbd_init, i8042_tstc and i8042_getc + for cfb_console. Supports cursor blinking. + +- Video support: + CONFIG_VIDEO + + Define this to enable video support (for output to + video). + + CONFIG_VIDEO_CT69000 + + Enable Chips & Technologies 69000 Video chip + + CONFIG_VIDEO_SMI_LYNXEM + Enable Silicon Motion SMI 712/710/810 Video chip + Videomode are selected via environment 'videomode' with + standard LiLo mode numbers. + Following modes are supported (* is default): + + 800x600 1024x768 1280x1024 + 256 (8bit) 303* 305 307 + 65536 (16bit) 314 317 31a + 16,7 Mill (24bit) 315 318 31b + (i.e. setenv videomode 317; saveenv; reset;) + +- LCD Support: CONFIG_LCD + + Define this to enable LCD support (for output to LCD + display); also select one of the supported displays + by defining one of these: + + CONFIG_NEC_NL6648AC33: + + NEC NL6648AC33-18. Active, color, single scan. + + CONFIG_NEC_NL6648BC20 + + NEC NL6648BC20-08. 6.5", 640x480. + Active, color, single scan. + + CONFIG_SHARP_16x9 + + Sharp 320x240. Active, color, single scan. + It isn't 16x9, and I am not sure what it is. + + CONFIG_SHARP_LQ64D341 + + Sharp LQ64D341 display, 640x480. + Active, color, single scan. + + CONFIG_HLD1045 + + HLD1045 display, 640x480. + Active, color, single scan. + + CONFIG_OPTREX_BW + + Optrex CBL50840-2 NF-FW 99 22 M5 + or + Hitachi LMG6912RPFC-00T + or + Hitachi SP14Q002 + + 320x240. Black & white. + + Normally display is black on white background; define + CFG_WHITE_ON_BLACK to get it inverted. + +- Ethernet address: + CONFIG_ETHADDR + CONFIG_ETH2ADDR + CONFIG_ETH3ADDR + + Define a default value for ethernet address to use + for the respective ethernet interface, in case this + is not determined automatically. + +- IP address: + CONFIG_IPADDR + + Define a default value for the IP address to use for + the default ethernet interface, in case this is not + determined through e.g. bootp. + +- Server IP address: + CONFIG_SERVERIP + + Defines a default value for theIP address of a TFTP + server to contact when using the "tftboot" command. + +- BOOTP Recovery Mode: + CONFIG_BOOTP_RANDOM_DELAY + + If you have many targets in a network that try to + boot using BOOTP, you may want to avoid that all + systems send out BOOTP requests at precisely the same + moment (which would happen for instance at recovery + from a power failure, when all systems will try to + boot, thus flooding the BOOTP server. Defining + CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be + inserted before sending out BOOTP requests. The + following delays are insterted then: + + 1st BOOTP request: delay 0 ... 1 sec + 2nd BOOTP request: delay 0 ... 2 sec + 3rd BOOTP request: delay 0 ... 4 sec + 4th and following + BOOTP requests: delay 0 ... 8 sec + +- Status LED: CONFIG_STATUS_LED + + Several configurations allow to display the current + status using a LED. For instance, the LED will blink + fast while running U-Boot code, stop blinking as + soon as a reply to a BOOTP request was received, and + start blinking slow once the Linux kernel is running + (supported by a status LED driver in the Linux + kernel). Defining CONFIG_STATUS_LED enables this + feature in U-Boot. + +- CAN Support: CONFIG_CAN_DRIVER + + Defining CONFIG_CAN_DRIVER enables CAN driver support + on those systems that support this (optional) + feature, like the TQM8xxL modules. + +- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C + + Enables I2C serial bus commands. If this is selected, + either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined + to include the appropriate I2C driver. + + See also: common/cmd_i2c.c for a description of the + command line interface. + + + CONFIG_HARD_I2C + + Selects the CPM hardware driver for I2C. + + CONFIG_SOFT_I2C + + Use software (aka bit-banging) driver instead of CPM + or similar hardware support for I2C. This is configured + via the following defines. + + I2C_INIT + + (Optional). Any commands necessary to enable I2C + controller or configure ports. + + I2C_PORT + + (Only for MPC8260 CPU). The I/O port to use (the code + assumes both bits are on the same port). Valid values + are 0..3 for ports A..D. + + I2C_ACTIVE + + The code necessary to make the I2C data line active + (driven). If the data line is open collector, this + define can be null. + + I2C_TRISTATE + + The code necessary to make the I2C data line tri-stated + (inactive). If the data line is open collector, this + define can be null. + + I2C_READ + + Code that returns TRUE if the I2C data line is high, + FALSE if it is low. + + I2C_SDA(bit) + + If <bit> is TRUE, sets the I2C data line high. If it + is FALSE, it clears it (low). + + I2C_SCL(bit) + + If <bit> is TRUE, sets the I2C clock line high. If it + is FALSE, it clears it (low). + + I2C_DELAY + + This delay is invoked four times per clock cycle so this + controls the rate of data transfer. The data rate thus + is 1 / (I2C_DELAY * 4). + +- SPI Support: CONFIG_SPI + + Enables SPI driver (so far only tested with + SPI EEPROM, also an instance works with Crystal A/D and + D/As on the SACSng board) + + CONFIG_SPI_X + + Enables extended (16-bit) SPI EEPROM addressing. + (symmetrical to CONFIG_I2C_X) + + CONFIG_SOFT_SPI + + Enables a software (bit-bang) SPI driver rather than + using hardware support. This is a general purpose + driver that only requires three general I/O port pins + (two outputs, one input) to function. If this is + defined, the board configuration must define several + SPI configuration items (port pins to use, etc). For + an example, see include/configs/sacsng.h. + +- FPGA Support: CONFIG_FPGA_COUNT + + Specify the number of FPGA devices to support. + + CONFIG_FPGA + + Used to specify the types of FPGA devices. For + example, + #define CONFIG_FPGA CFG_XILINX_VIRTEX2 + + CFG_FPGA_PROG_FEEDBACK + + Enable printing of hash marks during FPGA + configuration. + + CFG_FPGA_CHECK_BUSY + + Enable checks on FPGA configuration interface busy + status by the configuration function. This option + will require a board or device specific function to + be written. + + CONFIG_FPGA_DELAY + + If defined, a function that provides delays in the + FPGA configuration driver. + + CFG_FPGA_CHECK_CTRLC + + Allow Control-C to interrupt FPGA configuration + + CFG_FPGA_CHECK_ERROR + + Check for configuration errors during FPGA bitfile + loading. For example, abort during Virtex II + configuration if the INIT_B line goes low (which + indicated a CRC error). + + CFG_FPGA_WAIT_INIT + + Maximum time to wait for the INIT_B line to deassert + after PROB_B has been deasserted during a Virtex II + FPGA configuration sequence. The default time is 500 mS. + + CFG_FPGA_WAIT_BUSY + + Maximum time to wait for BUSY to deassert during + Virtex II FPGA configuration. The default is 5 mS. + + CFG_FPGA_WAIT_CONFIG + + Time to wait after FPGA configuration. The default is + 200 mS. + +- FPGA Support: CONFIG_FPGA_COUNT + + Specify the number of FPGA devices to support. + + CONFIG_FPGA + + Used to specify the types of FPGA devices. For example, + #define CONFIG_FPGA CFG_XILINX_VIRTEX2 + + CFG_FPGA_PROG_FEEDBACK + + Enable printing of hash marks during FPGA configuration. + + CFG_FPGA_CHECK_BUSY + + Enable checks on FPGA configuration interface busy + status by the configuration function. This option + will require a board or device specific function to + be written. + + CONFIG_FPGA_DELAY + + If defined, a function that provides delays in the FPGA + configuration driver. + + CFG_FPGA_CHECK_CTRLC + Allow Control-C to interrupt FPGA configuration + + CFG_FPGA_CHECK_ERROR + + Check for configuration errors during FPGA bitfile + loading. For example, abort during Virtex II + configuration if the INIT_B line goes low (which + indicated a CRC error). + + CFG_FPGA_WAIT_INIT + + Maximum time to wait for the INIT_B line to deassert + after PROB_B has been deasserted during a Virtex II + FPGA configuration sequence. The default time is 500 + mS. + + CFG_FPGA_WAIT_BUSY + + Maximum time to wait for BUSY to deassert during + Virtex II FPGA configuration. The default is 5 mS. + + CFG_FPGA_WAIT_CONFIG + + Time to wait after FPGA configuration. The default is + 200 mS. + +- Configuration Management: + CONFIG_IDENT_STRING + + If defined, this string will be added to the U-Boot + version information (U_BOOT_VERSION) + +- Vendor Parameter Protection: + + U-Boot considers the values of the environment + variables "serial#" (Board Serial Number) and + "ethaddr" (Ethernet Address) to bb parameters that + are set once by the board vendor / manufacturer, and + protects these variables from casual modification by + the user. Once set, these variables are read-only, + and write or delete attempts are rejected. You can + change this behviour: + + If CONFIG_ENV_OVERWRITE is #defined in your config + file, the write protection for vendor parameters is + completely disabled. Anybody can change or delte + these parameters. + + Alternatively, if you #define _both_ CONFIG_ETHADDR + _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default + ethernet address is installed in the environment, + which can be changed exactly ONCE by the user. [The + serial# is unaffected by this, i. e. it remains + read-only.] + +- Protected RAM: + CONFIG_PRAM + + Define this variable to enable the reservation of + "protected RAM", i. e. RAM which is not overwritten + by U-Boot. Define CONFIG_PRAM to hold the number of + kB you want to reserve for pRAM. You can overwrite + this default value by defining an environment + variable "pram" to the number of kB you want to + reserve. Note that the board info structure will + still show the full amount of RAM. If pRAM is + reserved, a new environment variable "mem" will + automatically be defined to hold the amount of + remaining RAM in a form that can be passed as boot + argument to Linux, for instance like that: + + setenv bootargs ... mem=\$(mem) + saveenv + + This way you can tell Linux not to use this memory, + either, which results in a memory region that will + not be affected by reboots. + + *WARNING* If your board configuration uses automatic + detection of the RAM size, you must make sure that + this memory test is non-destructive. So far, the + following board configurations are known to be + "pRAM-clean": + + ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL, + HERMES, IP860, RPXlite, LWMON, LANTEC, + PCU_E, FLAGADM, TQM8260 + +- Error Recovery: + CONFIG_PANIC_HANG + + Define this variable to stop the system in case of a + fatal error, so that you have to reset it manually. + This is probably NOT a good idea for an embedded + system where you want to system to reboot + automatically as fast as possible, but it may be + useful during development since you can try to debug + the conditions that lead to the situation. + + CONFIG_NET_RETRY_COUNT + + This variable defines the number of retries for + network operations like ARP, RARP, TFTP, or BOOTP + before giving up the operation. If not defined, a + default value of 5 is used. + +- Command Interpreter: + CFG_HUSH_PARSER + + Define this variable to enable the "hush" shell (from + Busybox) as command line interpreter, thus enabling + powerful command line syntax like + if...then...else...fi conditionals or `&&' and '||' + constructs ("shell scripts"). + + If undefined, you get the old, much simpler behaviour + with a somewhat smaller memory footprint. + + + CFG_PROMPT_HUSH_PS2 + + This defines the secondary prompt string, which is + printed when the command interpreter needs more input + to complete a command. Usually "> ". + + Note: + + In the current implementation, the local variables + space and global environment variables space are + separated. Local variables are those you define by + simply typing like `name=value'. To access a local + variable later on, you have write `$name' or + `${name}'; variable directly by typing say `$name' at + the command prompt. + + Global environment variables are those you use + setenv/printenv to work with. To run a command stored + in such a variable, you need to use the run command, + and you must not use the '$' sign to access them. + + To store commands and special characters in a + variable, please use double quotation marks + surrounding the whole text of the variable, instead + of the backslashes before semicolons and special + symbols. + +- Default Environment + CONFIG_EXTRA_ENV_SETTINGS + + Define this to contain any number of null terminated + strings (variable = value pairs) that will be part of + the default enviroment compiled into the boot image. + For example, place something like this in your + board's config file: + + #define CONFIG_EXTRA_ENV_SETTINGS \ + "myvar1=value1\0" \ + "myvar2=value2\0" + + Warning: This method is based on knowledge about the + internal format how the environment is stored by the + U-Boot code. This is NOT an official, expoerted + interface! Although it is unlikely that this format + will change soon, there is no guarantee either. + You better know what you are doing here. + + Note: overly (ab)use of the default environment is + discouraged. Make sure to check other ways to preset + the environment like the autoscript function or the + boot command first. + +- Show boot progress + CONFIG_SHOW_BOOT_PROGRESS + + Defining this option allows to add some board- + specific code (calling a user-provided function + "show_boot_progress(int)") that enables you to show + the system's boot progress on some display (for + example, some LED's) on your board. At the moment, + the following checkpoints are implemented: + + Arg Where When + 1 common/cmd_bootm.c before attempting to boot an image + -1 common/cmd_bootm.c Image header has bad magic number + 2 common/cmd_bootm.c Image header has correct magic number + -2 common/cmd_bootm.c Image header has bad checksum + 3 common/cmd_bootm.c Image header has correct checksum + -3 common/cmd_bootm.c Image data has bad checksum + 4 common/cmd_bootm.c Image data has correct checksum + -4 common/cmd_bootm.c Image is for unsupported architecture + 5 common/cmd_bootm.c Architecture check OK + -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) + 6 common/cmd_bootm.c Image Type check OK + -6 common/cmd_bootm.c gunzip uncompression error + -7 common/cmd_bootm.c Unimplemented compression type + 7 common/cmd_bootm.c Uncompression OK + -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone) + 8 common/cmd_bootm.c Image Type check OK + -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX) + 9 common/cmd_bootm.c Start initial ramdisk verification + -10 common/cmd_bootm.c Ramdisk header has bad magic number + -11 common/cmd_bootm.c Ramdisk header has bad checksum + 10 common/cmd_bootm.c Ramdisk header is OK + -12 common/cmd_bootm.c Ramdisk data has bad checksum + 11 common/cmd_bootm.c Ramdisk data has correct checksum + 12 common/cmd_bootm.c Ramdisk verification complete, start loading + -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk) + 13 common/cmd_bootm.c Start multifile image verification + 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue. + 15 common/cmd_bootm.c All preparation done, transferring control to OS + + -1 common/cmd_doc.c Bad usage of "doc" command + -1 common/cmd_doc.c No boot device + -1 common/cmd_doc.c Unknown Chip ID on boot device + -1 common/cmd_doc.c Read Error on boot device + -1 common/cmd_doc.c Image header has bad magic number + + -1 common/cmd_ide.c Bad usage of "ide" command + -1 common/cmd_ide.c No boot device + -1 common/cmd_ide.c Unknown boot device + -1 common/cmd_ide.c Unknown partition table + -1 common/cmd_ide.c Invalid partition type + -1 common/cmd_ide.c Read Error on boot device + -1 common/cmd_ide.c Image header has bad magic number + + -1 common/cmd_nvedit.c Environment not changable, but has bad CRC + + +Modem Support: +-------------- + +[so far only for SMDK2400 board] + +- Modem support endable: + CONFIG_MODEM_SUPPORT + +- RTS/CTS Flow control enable: + CONFIG_HWFLOW + +- Modem debug support: + CONFIG_MODEM_SUPPORT_DEBUG + + Enables debugging stuff (char screen[1024], dbg()) + for modem support. Useful only with BDI2000. + +- General: + + In the target system modem support is enabled when a + specific key (key combination) is pressed during + power-on. Otherwise U-Boot will boot normally + (autoboot). The key_pressed() fuction is called from + board_init(). Currently key_pressed() is a dummy + function, returning 1 and thus enabling modem + initialization. + + If there are no modem init strings in the + environment, U-Boot proceed to autoboot; the + previous output (banner, info printfs) will be + supressed, though. + + See also: doc/README.Modem + + + + +Configuration Settings: +----------------------- + +- CFG_LONGHELP: Defined when you want long help messages included; + undefine this when you're short of memory. + +- CFG_PROMPT: This is what U-Boot prints on the console to + prompt for user input. + +- CFG_CBSIZE: Buffer size for input from the Console + +- CFG_PBSIZE: Buffer size for Console output + +- CFG_MAXARGS: max. Number of arguments accepted for monitor commands + +- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to + the application (usually a Linux kernel) when it is + booted + +- CFG_BAUDRATE_TABLE: + List of legal baudrate settings for this board. + +- CFG_CONSOLE_INFO_QUIET + Suppress display of console information at boot. + +- CFG_CONSOLE_IS_IN_ENV + If the board specific function + extern int overwrite_console (void); + returns 1, the stdin, stderr and stdout are switched to the + serial port, else the settings in the environment are used. + +- CFG_CONSOLE_OVERWRITE_ROUTINE + Enable the call to overwrite_console(). + +- CFG_CONSOLE_ENV_OVERWRITE + Enable overwrite of previous console environment settings. + +- CFG_MEMTEST_START, CFG_MEMTEST_END: + Begin and End addresses of the area used by the + simple memory test. + +- CFG_ALT_MEMTEST: + Enable an alternate, more extensive memory test. + +- CFG_TFTP_LOADADDR: + Default load address for network file downloads + +- CFG_LOADS_BAUD_CHANGE: + Enable temporary baudrate change while serial download + +- CFG_SDRAM_BASE: + Physical start address of SDRAM. _Must_ be 0 here. + +- CFG_MBIO_BASE: + Physical start address of Motherboard I/O (if using a + Cogent motherboard) + +- CFG_FLASH_BASE: + Physical start address of Flash memory. + +- CFG_MONITOR_BASE: + Physical start address of boot monitor code (set by + make config files to be same as the text base address + (TEXT_BASE) used when linking) - same as + CFG_FLASH_BASE when booting from flash. + +- CFG_MONITOR_LEN: + Size of memory reserved for monitor code + +- CFG_MALLOC_LEN: + Size of DRAM reserved for malloc() use. + +- CFG_BOOTMAPSZ: + Maximum size of memory mapped by the startup code of + the Linux kernel; all data that must be processed by + the Linux kernel (bd_info, boot arguments, eventually + initrd image) must be put below this limit. + +- CFG_MAX_FLASH_BANKS: + Max number of Flash memory banks + +- CFG_MAX_FLASH_SECT: + Max number of sectors on a Flash chip + +- CFG_FLASH_ERASE_TOUT: + Timeout for Flash erase operations (in ms) + +- CFG_FLASH_WRITE_TOUT: + Timeout for Flash write operations (in ms) + +- CFG_DIRECT_FLASH_TFTP: + + Enable TFTP transfers directly to flash memory; + without this option such a download has to be + performed in two steps: (1) download to RAM, and (2) + copy from RAM to flash. + + The two-step approach is usually more reliable, since + you can check if the download worked before you erase + the flash, but in some situations (when sytem RAM is + too limited to allow for a tempory copy of the + downloaded image) this option may be very useful. + +- CFG_FLASH_CFI: + Define if the flash driver uses extra elements in the + common flash structure for storing flash geometry + +The following definitions that deal with the placement and management +of environment data (variable area); in general, we support the +following configurations: + +- CFG_ENV_IS_IN_FLASH: + + Define this if the environment is in flash memory. + + a) The environment occupies one whole flash sector, which is + "embedded" in the text segment with the U-Boot code. This + happens usually with "bottom boot sector" or "top boot + sector" type flash chips, which have several smaller + sectors at the start or the end. For instance, such a + layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In + such a case you would place the environment in one of the + 4 kB sectors - with U-Boot code before and after it. With + "top boot sector" type flash chips, you would put the + environment in one of the last sectors, leaving a gap + between U-Boot and the environment. + + - CFG_ENV_OFFSET: + + Offset of environment data (variable area) to the + beginning of flash memory; for instance, with bottom boot + type flash chips the second sector can be used: the offset + for this sector is given here. + + CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE. + + - CFG_ENV_ADDR: + + This is just another way to specify the start address of + the flash sector containing the environment (instead of + CFG_ENV_OFFSET). + + - CFG_ENV_SECT_SIZE: + + Size of the sector containing the environment. + + + b) Sometimes flash chips have few, equal sized, BIG sectors. + In such a case you don't want to spend a whole sector for + the environment. + + - CFG_ENV_SIZE: + + If you use this in combination with CFG_ENV_IS_IN_FLASH + and CFG_ENV_SECT_SIZE, you can specify to use only a part + of this flash sector for the environment. This saves + memory for the RAM copy of the environment. + + It may also save flash memory if you decide to use this + when your environment is "embedded" within U-Boot code, + since then the remainder of the flash sector could be used + for U-Boot code. It should be pointed out that this is + STRONGLY DISCOURAGED from a robustness point of view: + updating the environment in flash makes it always + necessary to erase the WHOLE sector. If something goes + wrong before the contents has been restored from a copy in + RAM, your target system will be dead. + + - CFG_ENV_ADDR_REDUND + CFG_ENV_SIZE_REDUND + + These settings describe a second storage area used to hold + a redundand copy of the environment data, so that there is + a valid backup copy in case there is a power failur during + a "saveenv" operation. + +BE CAREFUL! Any changes to the flash layout, and some changes to the +source code will make it necessary to adapt <board>/u-boot.lds* +accordingly! + + +- CFG_ENV_IS_IN_NVRAM: + + Define this if you have some non-volatile memory device + (NVRAM, battery buffered SRAM) which you want to use for the + environment. + + - CFG_ENV_ADDR: + - CFG_ENV_SIZE: + + These two #defines are used to determin the memory area you + want to use for environment. It is assumed that this memory + can just be read and written to, without any special + provision. + +BE CAREFUL! The first access to the environment happens quite early +in U-Boot initalization (when we try to get the setting of for the +console baudrate). You *MUST* have mappend your NVRAM area then, or +U-Boot will hang. + +Please note that even with NVRAM we still use a copy of the +environment in RAM: we could work on NVRAM directly, but we want to +keep settings there always unmodified except somebody uses "saveenv" +to save the current settings. + + +- CFG_ENV_IS_IN_EEPROM: + + Use this if you have an EEPROM or similar serial access + device and a driver for it. + + - CFG_ENV_OFFSET: + - CFG_ENV_SIZE: + + These two #defines specify the offset and size of the + environment area within the total memory of your EEPROM. + + - CFG_I2C_EEPROM_ADDR: + If defined, specified the chip address of the EEPROM device. + The default address is zero. + + - CFG_EEPROM_PAGE_WRITE_BITS: + If defined, the number of bits used to address bytes in a + single page in the EEPROM device. A 64 byte page, for example + would require six bits. + + - CFG_EEPROM_PAGE_WRITE_DELAY_MS: + If defined, the number of milliseconds to delay between + page writes. The default is zero milliseconds. + + - CFG_I2C_EEPROM_ADDR_LEN: + The length in bytes of the EEPROM memory array address. Note + that this is NOT the chip address length! + + - CFG_EEPROM_SIZE: + The size in bytes of the EEPROM device. + + - CFG_I2C_EEPROM_ADDR: + If defined, specified the chip address of the EEPROM device. + The default address is zero. + + - CFG_EEPROM_PAGE_WRITE_BITS: + If defined, the number of bits used to address bytes in a + single page in the EEPROM device. A 64 byte page, for example + would require six bits. + + - CFG_EEPROM_PAGE_WRITE_DELAY_MS: + If defined, the number of milliseconds to delay between + page writes. The default is zero milliseconds. + + - CFG_I2C_EEPROM_ADDR_LEN: + The length in bytes of the EEPROM memory array address. Note + that this is NOT the chip address length! + + - CFG_EEPROM_SIZE: + The size in bytes of the EEPROM device. + +- CFG_SPI_INIT_OFFSET + + Defines offset to the initial SPI buffer area in DPRAM. The + area is used at an early stage (ROM part) if the environment + is configured to reside in the SPI EEPROM: We need a 520 byte + scratch DPRAM area. It is used between the two initialization + calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems + to be a good choice since it makes it far enough from the + start of the data area as well as from the stack pointer. + +Please note that the environment is read-only as long as the monitor +has been relocated to RAM and a RAM copy of the environment has been +created; also, when using EEPROM you will have to use getenv_r() +until then to read environment variables. + +The environment is now protected by a CRC32 checksum. Before the +monitor is relocated into RAM, as a result of a bad CRC you will be +working with the compiled-in default environment - *silently*!!! +[This is necessary, because the first environment variable we need is +the "baudrate" setting for the console - if we have a bad CRC, we +don't have any device yet where we could complain.] + +Note: once the monitor has been relocated, then it will complain if +the default environment is used; a new CRC is computed as soon as you +use the "setenv" command to modify / delete / add any environment +variable [even when you try to delete a non-existing variable!]. + +Note2: you must edit your u-boot.lds file to reflect this +configuration. + + +Many of the options are named exactly as the corresponding Linux +kernel configuration options. The intention is to make it easier to +build a config tool - later. + +Low Level (hardware related) configuration options: + +- CFG_CACHELINE_SIZE: + Cache Line Size of the CPU. + +- CFG_DEFAULT_IMMR: + Default address of the IMMR after system reset. + Needed on some 8260 systems (MPC8260ADS and RPXsuper) + to be able to adjust the position of the IMMR + register after a reset. + +- CFG_IMMR: Physical address of the Internal Memory Mapped + Register; DO NOT CHANGE! (11-4) + [MPC8xx systems only] + +- CFG_INIT_RAM_ADDR: + + Start address of memory area tha can be used for + initial data and stack; please note that this must be + writable memory that is working WITHOUT special + initialization, i. e. you CANNOT use normal RAM which + will become available only after programming the + memory controller and running certain initialization + sequences. + + U-Boot uses the following memory types: + - MPC8xx and MPC8260: IMMR (internal memory of the CPU) + - MPC824X: data cache + - PPC4xx: data cache + +- CFG_INIT_DATA_OFFSET: + + Offset of the initial data structure in the memory + area defined by CFG_INIT_RAM_ADDR. Usually + CFG_INIT_DATA_OFFSET is chosen such that the initial + data is located at the end of the available space + (sometimes written as (CFG_INIT_RAM_END - + CFG_INIT_DATA_SIZE), and the initial stack is just + below that area (growing from (CFG_INIT_RAM_ADDR + + CFG_INIT_DATA_OFFSET) downward. + + Note: + On the MPC824X (or other systems that use the data + cache for initial memory) the address chosen for + CFG_INIT_RAM_ADDR is basically arbitrary - it must + point to an otherwise UNUSED address space between + the top of RAM and the start of the PCI space. + +- CFG_SIUMCR: SIU Module Configuration (11-6) + +- CFG_SYPCR: System Protection Control (11-9) + +- CFG_TBSCR: Time Base Status and Control (11-26) + +- CFG_PISCR: Periodic Interrupt Status and Control (11-31) + +- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30) + +- CFG_SCCR: System Clock and reset Control Register (15-27) + +- CFG_OR_TIMING_SDRAM: + SDRAM timing + +- CFG_MAMR_PTA: + periodic timer for refresh + +- CFG_DER: Debug Event Register (37-47) + +- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM, + CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP, + CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, + CFG_BR1_PRELIM: + Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) + +- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, + CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM, + CFG_OR3_PRELIM, CFG_BR3_PRELIM: + Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) + +- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, + CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL: + Machine Mode Register and Memory Periodic Timer + Prescaler definitions (SDRAM timing) + +- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]: + enable I2C microcode relocation patch (MPC8xx); + define relocation offset in DPRAM [DSP2] + +- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]: + enable SPI microcode relocation patch (MPC8xx); + define relocation offset in DPRAM [SCC4] + +- CFG_USE_OSCCLK: + Use OSCM clock mode on MBX8xx board. Be careful, + wrong setting might damage your board. Read + doc/README.MBX before setting this variable! + +Building the Software: +====================== + +Building U-Boot has been tested in native PPC environments (on a +PowerBook G3 running LinuxPPC 2000) and in cross environments +(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and +NetBSD 1.5 on x86). + +If you are not using a native PPC environment, it is assumed that you +have the GNU cross compiling tools available in your path and named +with a prefix of "powerpc-linux-". If this is not the case, (e.g. if +you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change +the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU, +change it to: + + CROSS_COMPILE = ppc_4xx- + + +U-Boot is intended to be simple to build. After installing the +sources you must configure U-Boot for one specific board type. This +is done by typing: + + make NAME_config + +where "NAME_config" is the name of one of the existing +configurations; the following names are supported: + + ADCIOP_config GTH_config TQM850L_config + ADS860_config IP860_config TQM855L_config + AR405_config IVML24_config TQM860L_config + CANBT_config IVMS8_config WALNUT405_config + CPCI405_config LANTEC_config cogent_common_config + CPCIISER4_config MBX_config cogent_mpc8260_config + CU824_config MBX860T_config cogent_mpc8xx_config + ESTEEM192E_config RPXlite_config hermes_config + ETX094_config RPXsuper_config hymod_config + FADS823_config SM850_config lwmon_config + FADS850SAR_config SPD823TS_config pcu_e_config + FADS860T_config SXNI855T_config rsdproto_config + FPS850L_config Sandpoint8240_config sbc8260_config + GENIETV_config TQM823L_config PIP405_config + GEN860T_config EBONY_config + +Note: for some board special configuration names may exist; check if + additional information is available from the board vendor; for + instance, the TQM8xxL systems run normally at 50 MHz and use a + SCC for 10baseT ethernet; there are also systems with 80 MHz + CPU clock, and an optional Fast Ethernet module is available + for CPU's with FEC. You can select such additional "features" + when chosing the configuration, i. e. + + make TQM860L_config + - will configure for a plain TQM860L, i. e. 50MHz, no FEC + + make TQM860L_FEC_config + - will configure for a TQM860L at 50MHz with FEC for ethernet + + make TQM860L_80MHz_config + - will configure for a TQM860L at 80 MHz, with normal 10baseT + interface + + make TQM860L_FEC_80MHz_config + - will configure for a TQM860L at 80 MHz with FEC for ethernet + + make TQM823L_LCD_config + - will configure for a TQM823L with U-Boot console on LCD + + make TQM823L_LCD_80MHz_config + - will configure for a TQM823L at 80 MHz with U-Boot console on LCD + + etc. + + + +Finally, type "make all", and you should get some working U-Boot +images ready for downlod to / installation on your system: + +- "u-boot.bin" is a raw binary image +- "u-boot" is an image in ELF binary format +- "u-boot.srec" is in Motorola S-Record format + + +Please be aware that the Makefiles assume you are using GNU make, so +for instance on NetBSD you might need to use "gmake" instead of +native "make". + + +If the system board that you have is not listed, then you will need +to port U-Boot to your hardware platform. To do this, follow these +steps: + +1. Add a new configuration option for your board to the toplevel + "Makefile", using the existing entries as examples. +2. Create a new directory to hold your board specific code. Add any + files you need. +3. If you're porting U-Boot to a new CPU, then also create a new + directory to hold your CPU specific code. Add any files you need. +4. Run "make config_name" with your new name. +5. Type "make", and you should get a working "u-boot.srec" file + to be installed on your target system. + [Of course, this last step is much harder than it sounds.] + + +Testing of U-Boot Modifications, Ports to New Hardware, etc.: +============================================================== + +If you have modified U-Boot sources (for instance added a new board +or support for new devices, a new CPU, etc.) you are expected to +provide feedback to the other developers. The feedback normally takes +the form of a "patch", i. e. a context diff against a certain (latest +official or latest in CVS) version of U-Boot sources. + +But before you submit such a patch, please verify that your modifi- +cation did not break existing code. At least make sure that *ALL* of +the supported boards compile WITHOUT ANY compiler warnings. To do so, +just run the "MAKEALL" script, which will configure and build U-Boot +for ALL supported system. Be warned, this will take a while. You can +select which (cross) compiler to use py passing a `CROSS_COMPILE' +environment variable to the script, i. e. to use the cross tools from +MontaVista's Hard Hat Linux you can type + + CROSS_COMPILE=ppc_8xx- MAKEALL + +or to build on a native PowerPC system you can type + + CROSS_COMPILE=' ' MAKEALL + +See also "U-Boot Porting Guide" below. + + + +Monitor Commands - Overview: +============================ + +go - start application at address 'addr' +run - run commands in an environment variable +bootm - boot application image from memory +bootp - boot image via network using BootP/TFTP protocol +tftpboot- boot image via network using TFTP protocol + and env variables "ipaddr" and "serverip" + (and eventually "gatewayip") +rarpboot- boot image via network using RARP/TFTP protocol +diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' +loads - load S-Record file over serial line +loadb - load binary file over serial line (kermit mode) +md - memory display +mm - memory modify (auto-incrementing) +nm - memory modify (constant address) +mw - memory write (fill) +cp - memory copy +cmp - memory compare +crc32 - checksum calculation +imd - i2c memory display +imm - i2c memory modify (auto-incrementing) +inm - i2c memory modify (constant address) +imw - i2c memory write (fill) +icrc32 - i2c checksum calculation +iprobe - probe to discover valid I2C chip addresses +iloop - infinite loop on address range +isdram - print SDRAM configuration information +sspi - SPI utility commands +base - print or set address offset +printenv- print environment variables +setenv - set environment variables +saveenv - save environment variables to persistent storage +protect - enable or disable FLASH write protection +erase - erase FLASH memory +flinfo - print FLASH memory information +bdinfo - print Board Info structure +iminfo - print header information for application image +coninfo - print console devices and informations +ide - IDE sub-system +loop - infinite loop on address range +mtest - simple RAM test +icache - enable or disable instruction cache +dcache - enable or disable data cache +reset - Perform RESET of the CPU +echo - echo args to console +version - print monitor version +help - print online help +? - alias for 'help' + + +Monitor Commands - Detailed Description: +======================================== + +TODO. + +For now: just type "help <command>". + + +Environment Variables: +====================== + +U-Boot supports user configuration using Environment Variables which +can be made persistent by saving to Flash memory. + +Environment Variables are set using "setenv", printed using +"printenv", and saved to Flash using "saveenv". Using "setenv" +without a value can be used to delete a variable from the +environment. As long as you don't save the environment you are +working with an in-memory copy. In case the Flash area containing the +environment is erased by accident, a default environment is provided. + +Some configuration options can be set using Environment Variables: + + baudrate - see CONFIG_BAUDRATE + + bootdelay - see CONFIG_BOOTDELAY + + bootcmd - see CONFIG_BOOTCOMMAND + + bootargs - Boot arguments when booting an RTOS image + + bootfile - Name of the image to load with TFTP + + autoload - if set to "no" (any string beginning with 'n'), + "bootp" will just load perform a lookup of the + configuration from the BOOTP server, but not try to + load any image using TFTP + + autostart - if set to "yes", an image loaded using the "bootp", + "rarpboot", "tftpboot" or "diskboot" commands will + be automatically started (by internally calling + "bootm") + + initrd_high - restrict positioning of initrd images: + If this variable is not set, initrd images will be + copied to the highest possible address in RAM; this + is usually what you want since it allows for + maximum initrd size. If for some reason you want to + make sure that the initrd image is loaded below the + CFG_BOOTMAPSZ limit, you can set this environment + variable to a value of "no" or "off" or "0". + Alternatively, you can set it to a maximum upper + address to use (U-Boot will still check that it + does not overwrite the U-Boot stack and data). + + For instance, when you have a system with 16 MB + RAM, and want to reseve 4 MB from use by Linux, + you can do this by adding "mem=12M" to the value of + the "bootargs" variable. However, now you must make + sure, that the initrd image is placed in the first + 12 MB as well - this can be done with + + setenv initrd_high 00c00000 + + ipaddr - IP address; needed for tftpboot command + + loadaddr - Default load address for commands like "bootp", + "rarpboot", "tftpboot" or "diskboot" + + loads_echo - see CONFIG_LOADS_ECHO + + serverip - TFTP server IP address; needed for tftpboot command + + bootretry - see CONFIG_BOOT_RETRY_TIME + + bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR + + bootstopkey - see CONFIG_AUTOBOOT_STOP_STR + + +The following environment variables may be used and automatically +updated by the network boot commands ("bootp" and "rarpboot"), +depending the information provided by your boot server: + + bootfile - see above + dnsip - IP address of your Domain Name Server + gatewayip - IP address of the Gateway (Router) to use + hostname - Target hostname + ipaddr - see above + netmask - Subnet Mask + rootpath - Pathname of the root filesystem on the NFS server + serverip - see above + + +There are two special Environment Variables: + + serial# - contains hardware identification information such + as type string and/or serial number + ethaddr - Ethernet address + +These variables can be set only once (usually during manufacturing of +the board). U-Boot refuses to delete or overwrite these variables +once they have been set once. + + +Please note that changes to some configuration parameters may take +only effect after the next boot (yes, that's just like Windoze :-). + + +Note for Redundant Ethernet Interfaces: +======================================= + +Some boards come with redundand ethernet interfaces; U-Boot supports +such configurations and is capable of automatic selection of a +"working" interface when needed. MAC assignemnt works as follows: + +Network interfaces are numbered eth0, eth1, eth2, ... Corresponding +MAC addresses can be stored in the environment as "ethaddr" (=>eth0), +"eth1addr" (=>eth1), "eth2addr", ... + +If the network interface stores some valid MAC address (for instance +in SROM), this is used as default address if there is NO correspon- +ding setting in the environment; if the corresponding environment +variable is set, this overrides the settings in the card; that means: + +o If the SROM has a valid MAC address, and there is no address in the + environment, the SROM's address is used. + +o If there is no valid address in the SROM, and a definition in the + environment exists, then the value from the environment variable is + used. + +o If both the SROM and the environment contain a MAC address, and + both addresses are the same, this MAC address is used. + +o If both the SROM and the environment contain a MAC address, and the + addresses differ, the value from the environment is used and a + warning is printed. + +o If neither SROM nor the environment contain a MAC address, an error + is raised. + + + +Image Formats: +============== + +The "boot" commands of this monitor operate on "image" files which +can be basicly anything, preceeded by a special header; see the +definitions in include/image.h for details; basicly, the header +defines the following image properties: + +* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, + 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, + LynxOS, pSOS, QNX; + Currently supported: Linux, NetBSD, VxWorks, QNX). +* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, + IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; + Currently supported: PowerPC). +* Compression Type (Provisions for uncompressed, gzip, bzip2; + Currently supported: uncompressed, gzip). +* Load Address +* Entry Point +* Image Name +* Image Timestamp + +The header is marked by a special Magic Number, and both the header +and the data portions of the image are secured against corruption by +CRC32 checksums. + + +Linux Support: +============== + +Although U-Boot should support any OS or standalone application +easily, Linux has always been in the focus during the design of +U-Boot. + +U-Boot includes many features that so far have been part of some +special "boot loader" code within the Linux kernel. Also, any +"initrd" images to be used are no longer part of one big Linux image; +instead, kernel and "initrd" are separate images. This implementation +serves serveral purposes: + +- the same features can be used for other OS or standalone + applications (for instance: using compressed images to reduce the + Flash memory footprint) + +- it becomes much easier to port new Linux kernel versions because + lots of low-level, hardware dependend stuff are done by U-Boot + +- the same Linux kernel image can now be used with different "initrd" + images; of course this also means that different kernel images can + be run with the same "initrd". This makes testing easier (you don't + have to build a new "zImage.initrd" Linux image when you just + change a file in your "initrd"). Also, a field-upgrade of the + software is easier now. + + +Linux HOWTO: +============ + +Porting Linux to U-Boot based systems: +--------------------------------------- + +U-Boot cannot save you from doing all the necessary modifications to +configure the Linux device drivers for use with your target hardware +(no, we don't intend to provide a full virtual machine interface to +Linux :-). + +But now you can ignore ALL boot loader code (in arch/ppc/mbxboot). + +Just make sure your machine specific header file (for instance +include/asm-ppc/tqm8xx.h) includes the same definition of the Board +Information structure as we define in include/u-boot.h, and make +sure that your definition of IMAP_ADDR uses the same value as your +U-Boot configuration in CFG_IMMR. + + +Configuring the Linux kernel: +----------------------------- + +No specific requirements for U-Boot. Make sure you have some root +device (initial ramdisk, NFS) for your target system. + + +Building a Linux Image: +----------------------- + +No specific requirements for U-Boot. There is no need to add a +"ramdisk.image.gz" file when building the kernel, even when you +intend to run it with initial ramdisk. + +Example: + + make TQM850L_config + make oldconfig + make dep + make zImage + +However, we don't use the 'zImage' (= 'arch/ppc/mbxboot/zvmlinux') we +build this way. The 'zImage' includes the old boot loader code which +we don't ned any more. Instead, we use the raw (compressed) Linux +kernel image in 'arch/ppc/coffboot/vmlinux.gz'. + +There is a special tool (in 'tools/mkimage') to encapsulate this +image with header information, CRC32 checksum etc. for use with +U-Boot: + +In the first form (with "-l" option) mkimage lists the information +contained in the header of an existing U-Boot image; this includes +checksum verification: + + tools/mkimage -l image + -l ==> list image header information + +The second form (with "-d" option) is used to build a U-Boot image +from a "data file" which is used as image payload: + + tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ + -n name -d data_file image + -A ==> set architecture to 'arch' + -O ==> set operating system to 'os' + -T ==> set image type to 'type' + -C ==> set compression type 'comp' + -a ==> set load address to 'addr' (hex) + -e ==> set entry point to 'ep' (hex) + -n ==> set image name to 'name' + -d ==> use image data from 'datafile' + +Right now, all Linux kernels use the same load address (0x00000000), +but the entry point address depends on the kernel version: + +- 2.2.x kernels have the entry point at 0x0000000C, +- 2.3.x and 2.4.x kernels have the entry point at 0x00000000. + +So a typical call to build a U-Boot image would read: + + -> tools/mkimage -n '2.2.13 for initrd on TQM850L' \ + > -A ppc -O linux -T kernel -C gzip -a 00000000 -e 0000000C \ + > -d /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux.gz \ + > examples/image-2.2.13-initrd + Image Name: 2.2.13 for initrd on TQM850L + Created: Wed Jul 19 02:34:59 2000 + Image Type: PowerPC Linux Kernel Image (gzip compressed) + Data Size: 335725 Bytes = 327.86 kB = 0.32 MB + Load Address: 0x00000000 + Entry Point: 0x0000000c + +To verify the contents of the image (or check for corruption): + + -> tools/mkimage -l examples/image-2.2.13-initrd + Image Name: 2.2.13 for initrd on TQM850L + Created: Wed Jul 19 02:34:59 2000 + Image Type: PowerPC Linux Kernel Image (gzip compressed) + Data Size: 335725 Bytes = 327.86 kB = 0.32 MB + Load Address: 0x00000000 + Entry Point: 0x0000000c + +NOTE: for embedded systems where boot time is critical you can trade +speed for memory and install an UNCOMPRESSED image instead: this +needs more space in Flash, but boots much faster since it does not +need to be uncompressed: + + -> gunzip /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux.gz + -> tools/mkimage -n '2.2.13 for initrd on TQM850L' \ + > -A ppc -O linux -T kernel -C none -a 00000000 -e 0000000C \ + > -d /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux \ + > examples/image-2.2.13-initrd-uncompressed + Image Name: 2.2.13 for initrd on TQM850L + Created: Wed Jul 19 02:34:59 2000 + Image Type: PowerPC Linux Kernel Image (uncompressed) + Data Size: 792160 Bytes = 773.59 kB = 0.76 MB + Load Address: 0x00000000 + Entry Point: 0x0000000c + + +Similar you can build U-Boot images from a 'ramdisk.image.gz' file +when your kernel is intended to use an initial ramdisk: + + -> tools/mkimage -n 'Simple Ramdisk Image' \ + > -A ppc -O linux -T ramdisk -C gzip \ + > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd + Image Name: Simple Ramdisk Image + Created: Wed Jan 12 14:01:50 2000 + Image Type: PowerPC Linux RAMDisk Image (gzip compressed) + Data Size: 566530 Bytes = 553.25 kB = 0.54 MB + Load Address: 0x00000000 + Entry Point: 0x00000000 + + +Installing a Linux Image: +------------------------- + +To downloading a U-Boot image over the serial (console) interface, +you must convert the image to S-Record format: + + objcopy -I binary -O srec examples/image examples/image.srec + +The 'objcopy' does not understand the information in the U-Boot +image header, so the resulting S-Record file will be relative to +address 0x00000000. To load it to a given address, you need to +specify the target address as 'offset' parameter with the 'loads' +command. + +Example: install the image to address 0x40100000 (which on the +TQM8xxL is in the first Flash bank): + + => erase 40100000 401FFFFF + + .......... done + Erased 8 sectors + + => loads 40100000 + ## Ready for S-Record download ... + ~>examples/image.srec + 1 2 3 4 5 6 7 8 9 10 11 12 13 ... + ... + 15989 15990 15991 15992 + [file transfer complete] + [connected] + ## Start Addr = 0x00000000 + + +You can check the success of the download using the 'iminfo' command; +this includes a checksum verification so you can be sure no data +corruption happened: + + => imi 40100000 + + ## Checking Image at 40100000 ... + Image Name: 2.2.13 for initrd on TQM850L + Image Type: PowerPC Linux Kernel Image (gzip compressed) + Data Size: 335725 Bytes = 327 kB = 0 MB + Load Address: 00000000 + Entry Point: 0000000c + Verifying Checksum ... OK + + + +Boot Linux: +----------- + +The "bootm" command is used to boot an application that is stored in +memory (RAM or Flash). In case of a Linux kernel image, the contents +of the "bootargs" environment variable is passed to the kernel as +parameters. You can check and modify this variable using the +"printenv" and "setenv" commands: + + + => printenv bootargs + bootargs=root=/dev/ram + + => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 + + => printenv bootargs + bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 + + => bootm 40020000 + ## Booting Linux kernel at 40020000 ... + Image Name: 2.2.13 for NFS on TQM850L + Image Type: PowerPC Linux Kernel Image (gzip compressed) + Data Size: 381681 Bytes = 372 kB = 0 MB + Load Address: 00000000 + Entry Point: 0000000c + Verifying Checksum ... OK + Uncompressing Kernel Image ... OK + 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 + Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 + time_init: decrementer frequency = 187500000/60 + Calibrating delay loop... 49.77 BogoMIPS + Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] + ... + +If you want to boot a Linux kernel with initial ram disk, you pass +the memory addreses of both the kernel and the initrd image (PPBCOOT +format!) to the "bootm" command: + + => imi 40100000 40200000 + + ## Checking Image at 40100000 ... + Image Name: 2.2.13 for initrd on TQM850L + Image Type: PowerPC Linux Kernel Image (gzip compressed) + Data Size: 335725 Bytes = 327 kB = 0 MB + Load Address: 00000000 + Entry Point: 0000000c + Verifying Checksum ... OK + + ## Checking Image at 40200000 ... + Image Name: Simple Ramdisk Image + Image Type: PowerPC Linux RAMDisk Image (gzip compressed) + Data Size: 566530 Bytes = 553 kB = 0 MB + Load Address: 00000000 + Entry Point: 00000000 + Verifying Checksum ... OK + + => bootm 40100000 40200000 + ## Booting Linux kernel at 40100000 ... + Image Name: 2.2.13 for initrd on TQM850L + Image Type: PowerPC Linux Kernel Image (gzip compressed) + Data Size: 335725 Bytes = 327 kB = 0 MB + Load Address: 00000000 + Entry Point: 0000000c + Verifying Checksum ... OK + Uncompressing Kernel Image ... OK + ## Loading RAMDisk Image at 40200000 ... + Image Name: Simple Ramdisk Image + Image Type: PowerPC Linux RAMDisk Image (gzip compressed) + Data Size: 566530 Bytes = 553 kB = 0 MB + Load Address: 00000000 + Entry Point: 00000000 + Verifying Checksum ... OK + Loading Ramdisk ... OK + 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 + Boot arguments: root=/dev/ram + time_init: decrementer frequency = 187500000/60 + Calibrating delay loop... 49.77 BogoMIPS + ... + RAMDISK: Compressed image found at block 0 + VFS: Mounted root (ext2 filesystem). + + bash# + + +Standalone HOWTO: +================= + +One of the features of U-Boot is that you can dynamically load and +run "standalone" applications, which can use some resources of +U-Boot like console I/O functions or interrupt services. + +Two simple examples are included with the sources: + +"Hello World" Demo: +------------------- + +'examples/hello_world.c' contains a small "Hello World" Demo +application; it is automatically compiled when you build U-Boot. +It's configured to run at address 0x00040004, so you can play with it +like that: + + => loads + ## Ready for S-Record download ... + ~>examples/hello_world.srec + 1 2 3 4 5 6 7 8 9 10 11 ... + [file transfer complete] + [connected] + ## Start Addr = 0x00040004 + + => go 40004 Hello World! This is a test. + ## Starting application at 0x00040004 ... + Hello World + argc = 7 + argv[0] = "40004" + argv[1] = "Hello" + argv[2] = "World!" + argv[3] = "This" + argv[4] = "is" + argv[5] = "a" + argv[6] = "test." + argv[7] = "<NULL>" + Hit any key to exit ... + + ## Application terminated, rc = 0x0 + +Another example, which demonstrates how to register a CPM interrupt +handler with the U-Boot code, can be found in 'examples/timer.c'. +Here, a CPM timer is set up to generate an interrupt every second. +The interrupt service routine is trivial, just printing a '.' +character, but this is just a demo program. The application can be +controlled by the following keys: + + ? - print current values og the CPM Timer registers + b - enable interrupts and start timer + e - stop timer and disable interrupts + q - quit application + + => loads + ## Ready for S-Record download ... + ~>examples/timer.srec + 1 2 3 4 5 6 7 8 9 10 11 ... + [file transfer complete] + [connected] + ## Start Addr = 0x00040004 + + => go 40004 + ## Starting application at 0x00040004 ... + TIMERS=0xfff00980 + Using timer 1 + tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 + +Hit 'b': + [q, b, e, ?] Set interval 1000000 us + Enabling timer +Hit '?': + [q, b, e, ?] ........ + tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 +Hit '?': + [q, b, e, ?] . + tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 +Hit '?': + [q, b, e, ?] . + tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 +Hit '?': + [q, b, e, ?] . + tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 +Hit 'e': + [q, b, e, ?] ...Stopping timer +Hit 'q': + [q, b, e, ?] ## Application terminated, rc = 0x0 + + +NetBSD Notes: +============= + +Starting at version 0.9.2, U-Boot supports NetBSD both as host +(build U-Boot) and target system (boots NetBSD/mpc8xx). + +Building requires a cross environment; it is known to work on +NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also +need gmake since the Makefiles are not compatible with BSD make). +Note that the cross-powerpc package does not install include files; +attempting to build U-Boot will fail because <machine/ansi.h> is +missing. This file has to be installed and patched manually: + + # cd /usr/pkg/cross/powerpc-netbsd/include + # mkdir powerpc + # ln -s powerpc machine + # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h + # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST + +Native builds *don't* work due to incompatibilities between native +and U-Boot include files. + +Booting assumes that (the first part of) the image booted is a +stage-2 loader which in turn loads and then invokes the kernel +proper. Loader sources will eventually appear in the NetBSD source +tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the +meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for +details. + + +Implementation Internals: +========================= + +The following is not intended to be a complete description of every +implementation detail. However, it should help to understand the +inner workings of U-Boot and make it easier to port it to custom +hardware. + + +Initial Stack, Global Data: +--------------------------- + +The implementation of U-Boot is complicated by the fact that U-Boot +starts running out of ROM (flash memory), usually without access to +system RAM (because the memory controller is not initialized yet). +This means that we don't have writable Data or BSS segments, and BSS +is not initialized as zero. To be able to get a C environment working +at all, we have to allocate at least a minimal stack. Implementation +options for this are defined and restricted by the CPU used: Some CPU +models provide on-chip memory (like the IMMR area on MPC8xx and +MPC826x processors), on others (parts of) the data cache can be +locked as (mis-) used as memory, etc. + +It is essential to remember this, since it has some impact on the C +code for the initialization procedures: + +* Initialized global data (data segment) is read-only. Do not attempt + to write it. + +* Do not use any unitialized global data (or implicitely initialized + as zero data - BSS segment) at all - this is undefined, initiali- + zation is performed later (when relocationg to RAM). + +* Stack space is very limited. Avoid big data buffers or things like + that. + +Having only the stack as writable memory limits means we cannot use +normal global data to share information beween the code. But it +turned out that the implementation of U-Boot can be greatly +simplified by making a global data structure (gd_t) available to all +functions. We could pass a pointer to this data as argument to _all_ +functions, but this would bloat the code. Instead we use a feature of +the GCC compiler (Global Register Variables) to share the data: we +place a pointer (gd) to the global data into a register which we +reserve for this purpose. + +When chosing a register for such a purpose we are restricted by the +relevant (E)ABI specifications for the current architecture, and by +GCC's implementation. + +For PowerPC, the following registers have specific use: + R1: stack pointer + R2: TOC pointer + R3-R4: parameter passing and return values + R5-R10: parameter passing + R13: small data area pointer + R30: GOT pointer + R31: frame pointer + + (U-Boot also uses R14 as internal GOT pointer.) + + ==> U-Boot will use R29 to hold a pointer to the global data + + Note: on PPC, we could use a static initializer (since the + address of the global data structure is known at compile time), + but it turned out that reserving a register results in somewhat + smaller code - although the code savings are not that big (on + average for all boards 752 bytes for the whole U-Boot image, + 624 text + 127 data). + +On ARM, the following registers are used: + + R0: function argument word/integer result + R1-R3: function argument word + R9: GOT pointer + R10: stack limit (used only if stack checking if enabled) + R11: argument (frame) pointer + R12: temporary workspace + R13: stack pointer + R14: link register + R15: program counter + + ==> U-Boot will use R8 to hold a pointer to the global data + + + +Memory Management: +------------------ + +U-Boot runs in system state and uses physical addresses, i.e. the +MMU is not used either for address mapping nor for memory protection. + +The available memory is mapped to fixed addresses using the memory +controller. In this process, a contiguous block is formed for each +memory type (Flash, SDRAM, SRAM), even when it consists of several +physical memory banks. + +U-Boot is installed in the first 128 kB of the first Flash bank (on +TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After +booting and sizing and initializing DRAM, the code relocates itself +to the upper end of DRAM. Immediately below the U-Boot code some +memory is reserved for use by malloc() [see CFG_MALLOC_LEN +configuration setting]. Below that, a structure with global Board +Info data is placed, followed by the stack (growing downward). + +Additionally, some exception handler code is copied to the low 8 kB +of DRAM (0x00000000 ... 0x00001FFF). + +So a typical memory configuration with 16 MB of DRAM could look like +this: + + 0x0000 0000 Exception Vector code + : + 0x0000 1FFF + 0x0000 2000 Free for Application Use + : + : + + : + : + 0x00FB FF20 Monitor Stack (Growing downward) + 0x00FB FFAC Board Info Data and permanent copy of global data + 0x00FC 0000 Malloc Arena + : + 0x00FD FFFF + 0x00FE 0000 RAM Copy of Monitor Code + ... eventually: LCD or video framebuffer + ... eventually: pRAM (Protected RAM - unchanged by reset) + 0x00FF FFFF [End of RAM] + + +System Initialization: +---------------------- + +In the reset configuration, U-Boot starts at the reset entry point +(on most PowerPC systens at address 0x00000100). Because of the reset +configuration for CS0# this is a mirror of the onboard Flash memory. +To be able to re-map memory U-Boot then jumps to it's link address. +To be able to implement the initialization code in C, a (small!) +initial stack is set up in the internal Dual Ported RAM (in case CPUs +which provide such a feature like MPC8xx or MPC8260), or in a locked +part of the data cache. After that, U-Boot initializes the CPU core, +the caches and the SIU. + +Next, all (potentially) available memory banks are mapped using a +preliminary mapping. For example, we put them on 512 MB boundaries +(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash +on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is +programmed for SDRAM access. Using the temporary configuration, a +simple memory test is run that determines the size of the SDRAM +banks. + +When there is more than one SDRAM bank, and the banks are of +different size, the larger is mapped first. For equal size, the first +bank (CS2#) is mapped first. The first mapping is always for address +0x00000000, with any additional banks following immediately to create +contiguous memory starting from 0. + +Then, the monitor installs itself at the upper end of the SDRAM area +and allocates memory for use by malloc() and for the global Board +Info data; also, the exception vector code is copied to the low RAM +pages, and the final stack is set up. + +Only after this relocation will you have a "normal" C environment; +until that you are restricted in several ways, mostly because you are +running from ROM, and because the code will have to be relocated to a +new address in RAM. + + +U-Boot Porting Guide: +---------------------- + +[Based on messages by Jerry Van Baren in the U-Boot-Users mailing +list, Octover 2002] + + +int main (int argc, char *argv[]) +{ + sighandler_t no_more_time; + + signal (SIGALRM, no_more_time); + alarm (PROJECT_DEADLINE - toSec (3 * WEEK)); + + if (available_money > available_manpower) { + pay consultant to port U-Boot; + return 0; + } + + Download latest U-Boot source; + + if (clueless) { + email ("Hi, I am new to U-Boot, how do I get started?"); + } + + while (learning) { + Read the README file in the top level directory; + Read http://www.denx.de/re/DPLG.html + Read the source, Luke; + } + + if (available_money > toLocalCurrency ($2500)) { + Buy a BDI2000; + } else { + Add a lot of aggravation and time; + } + + Create your own board support subdirectory; + + while (!running) { + do { + Add / modify source code; + } until (compiles); + Debug; + if (clueless) + email ("Hi, I am having problems..."); + } + Send patch file to Wolfgang; + + return 0; +} + +void no_more_time (int sig) +{ + hire_a_guru(); +} + + + +Coding Standards: +----------------- + +All contributions to U-Boot should conform to the Linux kernel +coding style; see the file "Documentation/CodingStyle" in your Linux +kernel source directory. + +Please note that U-Boot is implemented in C (and to some small parts +in Assembler); no C++ is used, so please do not use C++ style +comments (//) in your code. + +Submissions which do not conform to the standards may be returned +with a request to reformat the changes. + + +Submitting Patches: +------------------- + +Since the number of patches for U-Boot is growing, we need to +establish some rules. Submissions which do not conform to these rules +may be rejected, even when they contain important and valuable stuff. + + +When you send a patch, please include the following information with +it: + +* For bug fixes: a description of the bug and how your patch fixes + this bug. Please try to include a way of demonstrating that the + patch actually fixes something. + +* For new features: a description of the feature and your + implementation. + +* A CHANGELOG entry as plaintext (separate from the patch) + +* For major contributions, your entry to the CREDITS file + +* When you add support for a new board, don't forget to add this + board to the MAKEALL script, too. + +* If your patch adds new configuration options, don't forget to + document these in the README file. + +* The patch itself. If you are accessing the CVS repository use "cvs + update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your + version of diff does not support these options, then get the latest + version of GNU diff. + + We accept patches as plain text, MIME attachments or as uuencoded + gzipped text. + +Notes: + +* Before sending the patch, run the MAKEALL script on your patched + source tree and make sure that no errors or warnings are reported + for any of the boards. + +* Keep your modifications to the necessary minimum: A patch + containing several unrelated changes or arbitrary reformats will be + returned with a request to re-formatting / split it. + +* If you modify existing code, make sure that your new code does not + add to the memory footprint of the code ;-) Small is beautiful! + When adding new features, these should compile conditionally only + (using #ifdef), and the resulting code with the new feature + disabled must not need more memory than the old code without your + modification. |