pxe: implement fdtdir extlinux.conf tag
People who write (or scripts that auto-generate) extlinux.conf don't
want to know about HW-specific information such as FDT filenames. Create
a new extlinux.conf tag "fdtdir" that specifies only the directory where
FDT files are located, and defer all knowledge of the filename to U-Boot.
The algorithm implemented is:
==========
if $fdt_addr_r is set:
if "fdt" tag was specified in extlinux.conf:
load the FDT from the filename in the tag
else if "fdtdir" tag was specified in extlinux.conf:
if "fdtfile" is set in the environment:
load the FDT from filename in "$fdtfile"
else:
load the FDT from some automatically generated filename
if no FDT file was loaded, and $fdtaddr is set:
# This indicates an FDT packaged with firmware
use the FDT at $fdtaddr
==========
A small part of an example /boot/extlinux.conf might be:
==========
LABEL primary
LINUX zImage
FDTDIR ./
LABEL failsafe
LINUX bkp/zImage
FDTDIR bkp/
==========
... with /boot/tegra20-seaboard.dtb or /boot/bkp/tegra20-seaboard.dtb
being loaded by the sysboot/pxe code.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
1 file changed