Kontron COMe-bP5020 - Manual (Page 62)

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User Guide
COMe-bP5020
6.5.10 Booting an OS
6.5.10.1 Booting Linux
To boot Linux, at least a kernel image and a FDT (Flattened Device Tree) must be loaded to memory. Optionally, an “initrd” can
be loaded.
Furthermore, a command line must be prepared in the environment variable “bootargs”.
The boot itself is initiated with the “bootm” command.
To simplify the setup of the board, four predefined scripts are already programmed in the default environment:
» “nfsboot” to boot from a tftp server and mount the root over NFS
» “nandboot” to boot from the NAND flash and also mount it as root
» “sdboot” to boot from a SD Card and also mount it as root
» “multi_img_boot” to boot from the multi-image provided. The multi-image consists of a FDT, a kernel and a rootfs
For a one-time-only bootup, this can be accomplished with the “run” command, for example:
To make this permanent and have the board execute it automatically, it must be stored in the “bootcmd” environment variable
and the environment must be saved to flash.
Example:
6.5.10.2 Booting VxWorks ELF Images
The U-Boot boot process of a VxWorks ELF image requires that the following steps be performed:
» Load the VxWorks ELF image from media (Ethernet, Flash) into RAM
» Load the VxWorks FDT (Flattened Device Tree) from media (Ethernet, Flash) into RAM
» Setup and prepare the VxWorks FDT accordingly with the appropriate U-Boot commands:
» Boot from the VxWorks ELF image in RAM with U-Boot command
The VxWorks ELF image is generated with a suitable Wind River Workbench project based on Kontron’s VxWorks BSP (Board Sup-
port Package) for this product and with an appropriate profile.
Following typical build profiles are supported by the VxWorks BSP:
Table 50: VxWorks Build Prof iles
run nfsboot
setenv bootcmd 'run nandboot'
saveenv
fdt addr $fdtLoadAddr
fdt resize
fdt boardsetup
bootelf $imgLoadAddr
NAME DESCRIPTION
PROFILE_BOOTAPP VxWorks boot loader ELF image
PROFILE_STANDALONE_DEVELOPMENT VxWorks standalone ELF image