Specifications

U-Boot. Define this variable to hold the number of kB you want to reserve for pRAM. 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 ${bootargs} mem=\${mem}
=> saveenv
This way you can tell Linux not to use this memory, either, which results in a memory region that will not be
affected by reboots.
serverip: TFTP server IP address; needed for tftp command.•
serial#: contains hardware identification information such as type string and/or serial number.
This variable can be set only once (usually during manufacturing of the board). U-Boot refuses to
delete or overwrite this variable once it hass been set.
•
silent: If the configuration option CONFIG_SILENT_CONSOLE has been enabled for your board,
setting this variable to any value will suppress all console messages. Please see
doc/README.silent for details.
•
verify: If set to n or no disables the checksum calculation over the complete image in the bootm
command to trade speed for safety in the boot process. Note that the header checksum is still verified.
•
The following environment variables may be used and automatically updated by the network boot commands
(bootp, dhcp, or tftp), depending the information provided by your boot server:
bootfile: see above•
dnsip: IP address of your Domain Name Server•
gatewayip: IP address of the Gateway (Router) to use•
hostname: Target hostname•
ipaddr: see above•
netmask: Subnet Mask•
rootpath: Pathname of the root filesystem on the NFS server•
serverip: see above•
filesize: Size (as hex number in bytes) of the file downloaded using the last bootp, dhcp, or
tftp command.
•
5.11. U-Boot Scripting Capabilities
U-Boot allows to store commands or command sequences in a plain text file. Using the mkimage tool you
can then convert this file into a script image which can be executed using U-Boot's autoscr command.
For example, assume that you will have to run the following sequence of commands on many boards, so you
store them in a text file, say "setenv-commands":
bash$ cat setenv-commands
setenv loadaddr 00200000
echo ===== U-Boot settings =====
setenv u-boot /tftpboot/TQM860L/u-boot.bin
setenv u-boot_addr 40000000
setenv load_u-boot 'tftp ${loadaddr} ${u-boot}'
setenv install_u-boot 'protect off ${u-boot_addr} +${filesize};era ${u-boot_addr} +${filesize};cp.b ${loadaddr} ${u-boot_addr} ${filesize};saveenv'
setenv update_u-boot run load_u-boot install_u-boot
5.11. U-Boot Scripting Capabilities 81