PXE Bootmeth

PXE (Preboot eXecution-Environment) provides a way to boot an operating system over a network interface. The PXE bootmeth supports PXELINUX and allows U-Boot to provide a menu of possible Operating Systems from which the user can choose.

U-Boot includes a parser for the extlinux.conf file described here. It consists primarily of a list of named operating systems along with the kernel, initial ramdisk and other settings. The file is retrieved from a network server using the TFTP protocol.

When invoked on a bootdev, this bootmeth searches for the file and creates a bootflow if found. See PXELINUX for a full description of the search procedure.

When the bootflow is booted, the bootmeth calls pxe_setup_ctx() to set up the context, then pxe_process() to process the file. Depending on the contents, this may boot an Operating System or provide a list of options to the user, perhaps with a timeout.

The compatible string “u-boot,extlinux-pxe” is used for the driver. It is present if CONFIG_BOOTMETH_EXTLINUX_PXE is enabled.