IH_OS_U_BOOT u_boot_hush_start
+Versioning:
+===========
+
+U-Boot uses a 3 level version number containing a version, a
+sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
+sub-version "34", and patchlevel "4".
+
+The patchlevel is used to indicate certain stages of development
+between released versions, i. e. officially released versions of
+U-Boot will always have a patchlevel of "0".
+
+
Directory Hierarchy:
====================
- cpu/mpc8260 Files specific to Motorola MPC8260 CPU
- cpu/ppc4xx Files specific to IBM 4xx CPUs
+- board/LEOX/ Files specific to boards manufactured by The LEOX team
+- board/LEOX/elpt860 Files specific to ELPT860 boards
- board/RPXClassic
Files specific to RPXClassic boards
- board/RPXlite Files specific to RPXlite boards
CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
- CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L
+ CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
+ CONFIG_V37, CONFIG_ELPT860
ARM based boards:
-----------------
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
+ 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
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'.
+ 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
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".
+ 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.
+ 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
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.
+ (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!
CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
CONFIG_RTC_MC146818 - use MC146818 RTC
+ CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
+ CONFIG_RTC_DS164x - use Dallas DS164x 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 .
+ 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
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
+ 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;)
CONFIG_VIDEO_SED13806
- Enable Epson SED13806 driver. This driver supports 8bpp
+ Enable Epson SED13806 driver. This driver supports 8bpp
and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
or CONFIG_VIDEO_SED13806_16BPP
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.
+ See also: common/cmd_i2c.c for a description of the
+ command line interface.
CONFIG_HARD_I2C
I2C_INIT
- (Optional). Any commands necessary to enable I2C
- controller or configure ports.
+ (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.
+ (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
controls the rate of data transfer. The data rate thus
is 1 / (I2C_DELAY * 4).
+ CFG_I2C_INIT_BOARD
+
+ When a board is reset during an i2c bus transfer
+ chips might think that the current transfer is still
+ in progress. On some boards it is possible to access
+ the i2c SCLK line directly, either by using the
+ processor pin as a GPIO or by having a second pin
+ connected to the bus. If this option is defined a
+ custom i2c_init_board() routine in boards/xxx/board.c
+ is run early in the boot sequence.
+
- SPI Support: CONFIG_SPI
Enables SPI driver (so far only tested with
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.
+ 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.
+ Specify the number of FPGA devices to support.
- CONFIG_FPGA
+ CONFIG_FPGA
- Used to specify the types of FPGA devices. For
+ 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
+ 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.
+ 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.
+ If defined, a function that provides delays in the
+ FPGA configuration driver.
CFG_FPGA_CHECK_CTRLC
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).
+ 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.
+ 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.
+ 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
+ Time to wait after FPGA configuration. The default is
200 mS.
- FPGA Support: CONFIG_FPGA_COUNT
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.
+ 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
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).
+ 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.
+ 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.
+ 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.
+ 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)
+ 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:
+ 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
+ completely disabled. Anybody can change or delete
these parameters.
Alternatively, if you #define _both_ CONFIG_ETHADDR
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.
+ 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
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 `$name' at
- the command prompt.
+ In the current implementation, the local variables
+ space and global environment variables space are
+ separated. Local variables are those you define by
+ simply typing like `name=value'. To access a local
+ variable later on, you have write `$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 '$' sign to access them.
+ Global environment variables are those you use
+ setenv/printenv to work with. To run a command stored
+ in such a variable, you need to use the run command,
+ and you must not use the '$' sign to access them.
To store commands and special characters in a
variable, please use double quotation marks
- 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.
+ 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:
+ 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, exported
- interface! Although it is unlikely that this format
- will change soon, but there is no guarantee either.
+ 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, exported
+ interface! Although it is unlikely that this format
+ will change soon, but 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.
+ 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:
+ 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
Modem Support:
--------------
-[so far only for SMDK2400 board]
+[so far only for SMDK2400 and TRAB boards]
- Modem support endable:
CONFIG_MODEM_SUPPORT
- Modem debug support:
CONFIG_MODEM_SUPPORT_DEBUG
- Enables debugging stuff (char screen[1024], dbg())
- for modem support. Useful only with BDI2000.
+ 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.
+ 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.
+ 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
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
+ 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
- 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.
+ 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*
- 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
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.]
+The environment is 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.
+use the "saveenv" command to store a valid environment.
Low Level (hardware related) configuration options:
+---------------------------------------------------
- CFG_CACHELINE_SIZE:
Cache Line Size of the CPU.
CFG_ISA_IO_OFFSET
- defines the offset of register from address. It
- depends on which part of the data bus is connected to
- the fdc chipset. (default value 0)
+ defines the offset of register from address. It
+ depends on which part of the data bus is connected to
+ the fdc chipset. (default value 0)
- If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
- CFG_FDC_DRIVE_NUMBER are undefined, they take their
- default value.
+ If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
+ CFG_FDC_DRIVE_NUMBER are undefined, they take their
+ default value.
- if CFG_FDC_HW_INIT is defined, then the function
- fdc_hw_init() is called at the beginning of the FDC
- setup. fdc_hw_init() must be provided by the board
- source code. It is used to make hardware dependant
- initializations.
+ if CFG_FDC_HW_INIT is defined, then the function
+ fdc_hw_init() is called at the beginning of the FDC
+ setup. fdc_hw_init() must be provided by the board
+ source code. It is used to make hardware dependant
+ initializations.
- CFG_IMMR: Physical address of the Internal Memory Mapped
Register; DO NOT CHANGE! (11-4)
- MPC824X: data cache
- PPC4xx: data cache
-- CFG_INIT_DATA_OFFSET:
+- CFG_GBL_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
+ CFG_GBL_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.
+ CFG_GBL_DATA_OFFSET) downward.
Note:
On the MPC824X (or other systems that use the data
doc/README.MBX before setting this variable!
- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
- Offset of the bootmode word in DPRAM used by post
- (Power On Self Tests). This definition overrides
- #define'd default value in commproc.h resp.
- cpm_8260.h.
+ Offset of the bootmode word in DPRAM used by post
+ (Power On Self Tests). This definition overrides
+ #define'd default value in commproc.h resp.
+ cpm_8260.h.
Building the Software:
======================
FPS850L_config Sandpoint8240_config sbc8260_config
GENIETV_config TQM823L_config PIP405_config
GEN860T_config EBONY_config FPS860L_config
+ ELPT860_config
Note: for some board special configuration names may exist; check if
additional information is available from the board vendor; for
steps:
1. Add a new configuration option for your board to the toplevel
- "Makefile", using the existing entries as examples.
+ "Makefile" and to the "MAKEALL" script, using the existing
+ entries as examples. Note that here and at many other places
+ boards and other names are listed alphabetically sorted. Please
+ keep this order.
2. Create a new directory to hold your board specific code. Add any
- files you need.
+ files you need. In your board directory, you will need at least
+ the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
+3. Create a new configuration file "include/configs/<board>.h" for
+ your board
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.
+4. Run "make <board>_config" with your new name.
5. Type "make", and you should get a working "u-boot.srec" file
to be installed on your target system.
+6. Debug and solve any problems that might arise.
[Of course, this last step is much harder than it sounds.]
ipaddr - IP address; needed for tftpboot command
loadaddr - Default load address for commands like "bootp",
- "rarpboot", "tftpboot" or "diskboot"
+ "rarpboot", "tftpboot", "loadb" or "diskboot"
loads_echo - see CONFIG_LOADS_ECHO
bash#
+More About U-Boot Image Types:
+------------------------------
+
+U-Boot supports the following image types:
+
+ "Standalone Programs" are directly runnable in the environment
+ provided by U-Boot; it is expected that (if they behave
+ well) you can continue to work in U-Boot after return from
+ the Standalone Program.
+ "OS Kernel Images" are usually images of some Embedded OS which
+ will take over control completely. Usually these programs
+ will install their own set of exception handlers, device
+ drivers, set up the MMU, etc. - this means, that you cannot
+ expect to re-enter U-Boot except by resetting the CPU.
+ "RAMDisk Images" are more or less just data blocks, and their
+ parameters (address, size) are passed to an OS kernel that is
+ being started.
+ "Multi-File Images" contain several images, typically an OS
+ (Linux) kernel image and one or more data images like
+ RAMDisks. This construct is useful for instance when you want
+ to boot over the network using BOOTP etc., where the boot
+ server provides just a single image file, but you want to get
+ for instance an OS kernel and a RAMDisk image.
+
+ "Multi-File Images" start with a list of image sizes, each
+ image size (in bytes) specified by an "uint32_t" in network
+ byte order. This list is terminated by an "(uint32_t)0".
+ Immediately after the terminating 0 follow the images, one by
+ one, all aligned on "uint32_t" boundaries (size rounded up to
+ a multiple of 4 bytes).
+
+ "Firmware Images" are binary images containing firmware (like
+ U-Boot or FPGA images) which usually will be programmed to
+ flash memory.
+
+ "Script files" are command sequences that will be executed by
+ U-Boot's command interpreter; this feature is especially
+ useful when you configure U-Boot to use a real shell (hush)
+ as command interpreter.
+
Standalone HOWTO:
=================
[q, b, e, ?] ## Application terminated, rc = 0x0
+
+Minicom warning:
+================
+
+Over time, many people have reported problems when trying to used the
+"minicom" terminal emulation program for serial download. I (wd)
+consider minicom to be broken, and recommend not to use it. Under
+Unix, I recommend to use CKermit for general purpose use (and
+especially for kermit binary protocol download ("loadb" command), and
+use "cu" for S-Record download ("loads" command).
+
NetBSD Notes:
=============
MPC826x processors), on others (parts of) the data cache can be
locked as (mis-) used as memory, etc.
+ Chris Hallinan posted a good summy of these issues to the
+ u-boot-users mailing list:
+
+ Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
+ From: "Chris Hallinan" <clh@net1plus.com>
+ Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
+ ...
+
+ Correct me if I'm wrong, folks, but the way I understand it
+ is this: Using DCACHE as initial RAM for Stack, etc, does not
+ require any physical RAM backing up the cache. The cleverness
+ is that the cache is being used as a temporary supply of
+ necessary storage before the SDRAM controller is setup. It's
+ beyond the scope of this list to expain the details, but you
+ can see how this works by studying the cache architecture and
+ operation in the architecture and processor-specific manuals.
+
+ OCM is On Chip Memory, which I believe the 405GP has 4K. It
+ is another option for the system designer to use as an
+ initial stack/ram area prior to SDRAM being available. Either
+ option should work for you. Using CS 4 should be fine if your
+ board designers haven't used it for something that would
+ cause you grief during the initial boot! It is frequently not
+ used.
+
+ CFG_INIT_RAM_ADDR should be somewhere that won't interfere
+ with your processor/board/system design. The default value
+ you will find in any recent u-boot distribution in
+ Walnut405.h should work for you. I'd set it to a value larger
+ than your SDRAM module. If you have a 64MB SDRAM module, set
+ it above 400_0000. Just make sure your board has no resources
+ that are supposed to respond to that address! That code in
+ start.S has been around a while and should work as is when
+ you get the config right.
+
+ -Chris Hallinan
+ DS4.COM, Inc.
+
It is essential to remember this, since it has some impact on the C
code for the initialization procedures:
----------------------
[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
-list, Octover 2002]
+list, October 2002]
int main (int argc, char *argv[])
Download latest U-Boot source;
+ Subscribe to u-boot-users mailing list;
+
if (clueless) {
email ("Hi, I am new to U-Boot, how do I get started?");
}
Create your own board support subdirectory;
+ Create your own board config file;
+
while (!running) {
do {
Add / modify source code;