users_guide

Intel XScale PXA255 引导Linux的Redboot 版bootloader源代码！

The standard RedBoot command set is structured around the bootstrap
environment.  These commands are designed to be simple to use and
remember, while still providing sufficient power and flexibility to
be useful.  No attempt has been made to make RedBoot be the end-all
product.  As such, things such as the debug environment are left
to other modules such as GDB stubs which are typically included in
RedBoot.

Also, the command set may be extended on a platform basis.

Common commands:

The general format of commands is:
  <command> <options, paramters>
Elements are separated by the space character.  Other control characters,
such as TAB or editting keys (Insert) are not currently supported.

Numbers, such as a memory location, may be specified in either
decimal or hexadecimal (requires a 0x prefix).

Use the 'help' command to get limited help on command syntax.

    =======================================================================
    RedBoot> help
    Display (hex dump) a range of memory
       dump <location> [<length>]
    Manage FLASH images
       fis {cmds}
    Manage configuration kept in FLASH memory
       fconfig 
    Execute code at a location
       go [-w <timeout>] [entry]
    Help about help?
       help <topic>
    Load a file
       load [-raw] [-b <mem_addr>]]
    RedBoot> 
    =======================================================================

Commands may be abbreviated to any unique string.  E.g. 'lo' is equivalent
to 'loa' and 'load'.

- Download process

Currently, download is only supported using TFTP over a network.
Files to be downloaded may be executable images or raw data.
The format of the command is:
  RedBoot> load <file> [-v] [-b <location>] [-r]
where:
  <file> - The name of the file on the TFTP server.  Details of how
           this is specified are host specific.
  -v     - Display a small spinner (indicator) while download in 
           progress.  Just for feedback, especially during long loads.
  -b     - Specify the location in memory to load the file.  Executable
           images normally load at the location the file was linked for.
           This option allows the file to be loaded to a specific memory
           location, possibly overriding any assumed location.
  -r     - Download raw data.  Normally, the load command is used to 
           load executable images into memory.  This option allows for
           raw data to be loaded.  If this option is given, "-b" will
           be required as well.

    =======================================================================
    RedBoot> lo redboot.ROM -b 0x8c400000   
    Address offset = 0x0c400000
    Entry point: 0x80000000, address range: 0x80000000-0x8000fe80
    =======================================================================

- Flash Image System (FIS)

If the platform has flash memory, RedBoot can use this for image storage.
Executable images, as well as data, can be stored in flash in a simple
file store.  The 'fis' command is used to manipulate and maintain flash images.

The available 'fis' commands are:

  fis init [-f]

This command is used to initialize the Flash Image System (FIS).  It should
only be executed once, when RedBoot is first installed on the hardware.  
Subsequent executions will cause loss of data in the flash (previously saved
images will no longer be accessible).

If the "-f" option is specified, all blocks of flash memory will be erased
as part of this process.

    =======================================================================
    RedBoot> fis init -f
    About to initialize [format] FLASH image system - are you sure (y/n)? n
    =======================================================================

  fis list 

This command lists the images currently available in the FIS.  Certain images
are used by RedBoot and have fixed names.  Other images can be manipulated by
the user.

    =======================================================================
    RedBoot> fis list
    Name              FLASH addr   Mem addr    Length    Entry point
    RedBoot           0xA0000000   0xA0000000  0x020000  0x80000000
    RedBoot[backup]   0xA0020000   0x8C010000  0x010000  0x8C010000
    RedBoot config    0xA0FC0000   0xA0FC0000  0x020000  0x00000000
    FIS directory     0xA0FE0000   0xA0FE0000  0x020000  0x00000000
    =======================================================================

  fis free 

This command shows which areas of the flash memory are currently not in use.
In use means that the block contains non-erased contents.  Since it is possible
to force an image to be loaded at a particular flash location, this command
can be used to check whether that location is in use by any other image.

Note: there currently is no cross-checking between actual flash contents and
the image directory.  i.e. there could be a segment of flash which is not erased
that does not correspond to a named image, or vice-versa.

    =======================================================================
    RedBoot> fis free
      0xA0040000 .. 0xA07C0000
      0xA0840000 .. 0xA0FC0000
    =======================================================================

  fis create -b <mem_base> -l <length> [-f <flash_addr>] [-e <entry_point>] [-r <ram_addr>] <name>

This command creates an image in the FIS directory.  The data for the image must
exist in RAM memory before the copy.  Typically, one would use the RedBoot 'load'
command to load an image into RAM and then the 'fis create' command to write it
to flash. 

Options:
  <name> - The name of the file, as shown in the FIS directory.
  -b     - The location in RAM used to obtain the image *required*
  -l     - The length of the location *required*
  -f     - The location in flash for the image.  If not provided, the first free
           block which is large enough will be used.  See 'fis free'.
  -e     - The execution entry address.  Used if the starting address for an image
           is not known, or needs to be overridden.
  -r     - The location in RAM when the image is loaded via 'fis load'.  This only
           needs to be specified for images which will eventually loaded via 'fis load'.
           Fixed images, such as RedBoot itself, will not need this.

    =======================================================================
    RedBoot> fis create RedBoot -f 0xa0000000 -b 0x8c400000 -l 0x20000
    An image named 'RedBoot' exists - are you sure (y/n)? n
    RedBoot> fis create junk -b 0x8c400000 -l 0x20000
    ... Erase from 0xa0040000-0xa0060000: .
    ... Program from 0x8c400000-0x8c420000 at 0xa0040000: .
    ... Erase from 0xa0fe0000-0xa1000000: .
    ... Program from 0x8c7d0000-0x8c7f0000 at 0xa0fe0000: .
    =======================================================================

  fis load name

This command is used to transfer an image from flash memory to RAM.  Once loaded,
it may be executed using the 'go' command.

    =======================================================================
    RedBoot> fis load RedBoot[backup]
    RedBoot> go
    =======================================================================

  fis delete name

This command removes an image from the FIS.  The flash memory will be erased
as part of the execution of this command, as well as removal of the name from
the FIS directory.

    =======================================================================
    RedBoot> fis list
    Name              FLASH addr   Mem addr    Length    Entry point
    RedBoot           0xA0000000   0xA0000000  0x020000  0x80000000
    RedBoot[backup]   0xA0020000   0x8C010000  0x020000  0x8C010000
    RedBoot config    0xA0FC0000   0xA0FC0000  0x020000  0x00000000
    FIS directory     0xA0FE0000   0xA0FE0000  0x020000  0x00000000
    junk              0xA0040000   0x8C400000  0x020000  0x80000000
    RedBoot> fis delete junk
    Delete image 'junk' - are you sure (y/n)? y
    ... Erase from 0xa0040000-0xa0060000: .
    ... Erase from 0xa0fe0000-0xa1000000: .
    ... Program from 0x8c7d0000-0x8c7f0000 at 0xa0fe0000: .
    =======================================================================

  fis erase -f <flash_addr> -l <length>

This command is used to forceably erase a portion of flash memory.  There is
no cross-checking to ensure that the area being erased does not correspond to
a loaded image.

    =======================================================================
    RedBoot> fis erase -f 0xa0040000 -l 0x20000
    ... Erase from 0xa0040000-0xa0060000: .
    =======================================================================

  fis lock -f <flash_addr> -l <length>

This command is used to write-protect [lock] a portion of flash memory.  This
command is optional and will only be provided on hardware which can support
write-protection of the flash space.  Note: depending on the system, attempting
to write to write-protected flash may generate errors or warnings or be
benignly quiet.

    =======================================================================
    RedBoot> fis lock -f 0xa0040000 -l 0x20000
    ... Lock from 0xa0040000-0xa0060000: .
    =======================================================================

  fis unlock -f <flash_addr> -l <length>

This command is used to unlock forceably erase a portion of flash memory.  
It must be issued for regions which have been locked before the FIS can reuse
those portions of flash.

    =======================================================================
    RedBoot> fis unlock -f 0xa0040000 -l 0x20000
    ... Unlock from 0xa0040000-0xa0060000: .
    =======================================================================

- Persistent state [flash-based configuration] control

Additionally, if the platform has flash memory, certain control and configuration
information used by RedBoot can be stored in flash.  The details of what information
is maintained in flash differs based on the platform and the configuration.

However, the basic operation used to maintain this information is the same.
Using the 'fconfig' command, the information may be displayed and/or changed.

Usage:
  RedBoot> fconfig [-l]
If the optional flag "-l" is specified, the configuration data is simply listed.
Otherwise, each configuration parameter will be displayed and the user given
a chance to change it.  The entire value must be typed.  Typing just carriage
return will leave a value unchanged.  Boolean values may be entered by just the
first letter ('t' for true, 'f' for false).  At any time the editting process
may be stopped by entering just a '.' (period) on the line.  Entry of the character
'^' will move the editting back to the previous item.

If any changes are made in the configuration, then the updated data will be
written back to flash.

One item which is always present in the configuration data is the ability to
execute a script at boot/startup time.  A sequence of RedBoot commands can
be entered which will be executed when the system starts up.  Optionally,
a time out period can be provided which allows the user to abort the
startup script and proceed with normal command processing from the console.

    =======================================================================
    RedBoot> fconfig -l
    Run script at boot: false 
    Use BOOTP for network configuration: false 
    Local IP address: 192.168.1.29 
    Default server IP address: 192.168.1.101 
    GDB connection port: 9000 
    Network debug at boot time: false 
    =======================================================================

The following example sets a boot script and then shows it running.
    =======================================================================
    RedBoot> fconfig
             ^^^^^^^
    Run script at boot: false t
                              ^
    Boot script: 
    Enter script, terminate with empty line
    >> fi li
       ^^^^^
    >> 
       ^
    Boot script timeout: 0 10
                           ^^
    Use BOOTP for network configuration: false .
                                               ^
    Update RedBoot non-volatile configuration - are you sure (y/n)? y
                                                                    ^
    ... Erase from 0xa0fc0000-0xa0fe0000: .
    ... Program from 0x8c021f60-0x8c022360 at 0xa0fc0000: .
    RedBoot> 
    RedBoot(tm) debug environment - built 08:22:24, Aug 23 2000
    Copyright (C) 2000, Red Hat, Inc.
    
    RAM: 0x8c000000-0x8c800000
    FLASH: 0xa0000000 - 0xa1000000, 128 blocks of 0x00020000 bytes ea.
    Socket Communications, Inc: Low Power Ethernet CF Revision C 5V/3.3V 08/27/98
    IP: 192.168.1.29, Default server: 192.168.1.101
    == Executing boot script in 10 seconds - enter ^C to abort
    RedBoot> fi li
    Name              FLASH addr   Mem addr    Length    Entry point
    RedBoot           0xA0000000   0xA0000000  0x020000  0x80000000
    RedBoot[backup]   0xA0020000   0x8C010000  0x020000  0x8C010000
    RedBoot config    0xA0FC0000   0xA0FC0000  0x020000  0x00000000
    FIS directory     0xA0FE0000   0xA0FE0000  0x020000  0x00000000
    RedBoot>
             ^
    =======================================================================

Note: the '^' characters above indicate where something was entered on the
console.  As you can see, the 'fi li' command at the end came from the script,
not the console.  Once the script was executed, command processing reverted
to the console.

- Program execution

Once an image has been loaded into memory, either via the 'load' command
or the 'fis load' command, execution may be transfered to that image.
Note: the image is assumed to be a stand-alone entity, as RedBoot gives
the entire platform over to it.  Typical examples would be an eCos application
or a Linux kernel.

The format of the 'go' command is:
  RedBoot> go [-w <time>] [<location>]
Execution will begin at <location> if specified.  Otherwise, the "entry 
point" of the last image loaded will be used.

The "-w" option gives the user <time> seconds before execution begins.
The execution may be aborted by typing ^C on the console.  This mode
would typically be used in startup scripts.