Freescale Semiconductor TWR-MPC5125, User Manual, Page: 17 / 31

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TWR-MPC 5125
TWR-MPC5125 User Manual
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6.3 Configuring U-Boot
To boot the Linux kernel u-boot must have device tree support compiled in. To
verify this support is enabled, type help bootm at the u-boot prompt.
=> help bootm
bootm [addr [arg ...]]
- boot application image stored in memory
passing arguments 'arg ...'; when booting a Linux kernel, 'arg' can be the
address of an initrd image
When booting a Linux kernel which requires a flat device-tree
a third argument is required which is the address of the of the device-tree blob.
To boot that kernel without an initrd image, use a '-' for the second argument. If
you do not pass a third a bd_info struct will be passed instead
If the help message indicates that bootm takes three arguments then device
tree support is enabled. If not then it will be necessary to install a new u-boot.
See the Flashing U-Boot chapter below for details.
The factory installed u-boot has several commands predefined in the default
environment.
1). Print the existing u-boot configuration by typing “print” at the u-boot
prompt.
=> print
bootcmd=run nfsboot
bootdelay=5
baudrate=115200
loads_echo=1
preboot=echo;echo Type \"run flash_nfs\" to mount root filesystem over
NFS;echo
loadaddr=400000
u-boot_addr_r=200000
u-boot_addr=FFF00000
kernel_addr=FC040000