mvebu: clearfog: use partition uuid for root= bootarg

U-Boot already knows where it found the boot.scr, and
figuring out the partition UUID becomes trivial at this point.
This change allows booting OpenWrt from whatever storage it has been
flashed to: SD card, eMMC, USB disk or SATA disk.

Signed-off-by: Josua Mayer <josua.mayer97@gmail.com>
[replace lede with openwrt, redact commit message]
Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>

target/linux/mvebu/image/cfbase-boot.script

@@ -7,13 +7,14 @@
 # removed once U-Boot is able to detect the board variant.
 setenv fdtfile armada-388-clearfog-base.dtb
 
-# generate bootargs for rootfs on MMC
-if test "${devtype}" = "mmc"; then
-	setexpr openwrt_rootpart ${distro_bootpart} + 1
-	setenv bootargs ${bootargs} root=/dev/mmcblk${devnum}p${openwrt_rootpart} rootfstype=auto rootwait
-fi
+# rootfs is always on the next partition
+setexpr openwrt_rootpart ${distro_bootpart} + 1
+
+# figure out partition uuid to pass to the kernel as root=
+part uuid ${devtype} ${devnum}:${openwrt_rootpart} uuid
 
-# here one could add logic for other rootfs device types such as scsi and usb
+# generate bootargs (rootfs)
+setenv bootargs ${bootargs} root=PARTUUID=${uuid} rootfstype=auto rootwait
 
 # add console= option to bootargs, if any
 if test -n "${console}"; then

target/linux/mvebu/image/cfpro-boot.script

@@ -3,13 +3,14 @@
 # This script assumes that there is a boot partition, 
 # and that the root partition is always the next one.
 
-# generate bootargs for rootfs on MMC
-if test "${devtype}" = "mmc"; then
-	setexpr openwrt_rootpart ${distro_bootpart} + 1
-	setenv bootargs ${bootargs} root=/dev/mmcblk${devnum}p${openwrt_rootpart} rootfstype=auto rootwait
-fi
+# rootfs is always on the next partition
+setexpr openwrt_rootpart ${distro_bootpart} + 1
+
+# figure out partition uuid to pass to the kernel as root=
+part uuid ${devtype} ${devnum}:${openwrt_rootpart} uuid
 
-# here one could add logic for other rootfs device types such as scsi and usb
+# generate bootargs (rootfs)
+setenv bootargs ${bootargs} root=PARTUUID=${uuid} rootfstype=auto rootwait
 
 # add console= option to bootargs, if any
 if test -n "${console}"; then