U-Boot; What Is Ppcboot/U-Boot; Commonu-Bootcommands - ELTEC BAB 912 Hardware Documentation

Chapter 7. U-Boot

7.1. What is PPCBoot/U-Boot ?

PPCBoot is 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. PPCBoot is free software developed under GNU
General Public License. The development of PPCBoot is closely related to Linux. In october 2002 the
PPCBoot project has move into a new project called "U-Boot". All command names, functions and
environment are similar to PPCBoot. The name changed because more CPU architectures are supported.
For details go to http://sourceforge.net/projects/u-boot/. The "U-Boot" Universal Bootloader project also
provides firmware with full source code under GPL.
7.2. Common U-Boot commands
The following is a description of common U-Boot commands. A full list of supported commands is printed
by command h at U-Boot commandline. Paramters for any command can be obtained with h [command].
All address, size, offset, etc. values have to be entered in HEX format without leading '0x' or 'h'.
Table 7.1. Common U-Boot commands
Command Parameter
boot
bootm bootm [addr]
bootp bootp addr
dhcp dhcp addr
cp cp [.b, .w, .l] source
destination count
Description
Exec boot command bootcmd.
Boots a previous at address "addr" loaded U-Boot
image. "addr" has not to be given, because last
load address from bootp, will be taken as default.
Exec a BOOTP request and store the loaded
image at address "addr". A few environment
varibles will be set: ipaddress, bootfile, etc. ...
If no addr is given a board specific compiled in
default is used.
Exec a DHCP request and store the loaded image
at address "addr". A few environmnet varibles will
be set: ipaddress, bootfile, etc. ...
If no addr is given a board specific compiled in
default is used.
The dhcp_vendor-class-identifier environment may
be used to specify a ip/bootfile from DHCPD
configuration.
Copy memory areas (in previous erased Flash
also).
.b : Byte
.w : Short
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