[openwrt/openwrt] layerscape: fix board name for SD card boot

[LEDE Commits]

ynezz pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/3a99b624d87b32a95210ae58bd782a144ba12fc2

commit 3a99b624d87b32a95210ae58bd782a144ba12fc2
Author: Yangbo Lu <yangbo.lu at nxp.com>
AuthorDate: Thu May 28 13:50:42 2020 +0800

    layerscape: fix board name for SD card boot
    
    Many Layerscape boards support both flash boot and SD card boot.
    And different firmware and sysupgrade.bin are built for the two
    boot methods. To identify them, a fix could be done on board name
    by adding a postfix "-sdboot" for SD card boot.
    
    Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
---
 .../layerscape/base-files/lib/preinit/02_sysinfo_fixup      | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/target/linux/layerscape/base-files/lib/preinit/02_sysinfo_fixup b/target/linux/layerscape/base-files/lib/preinit/02_sysinfo_fixup
new file mode 100644
index 0000000000..1bbd8efbc6
--- /dev/null
+++ b/target/linux/layerscape/base-files/lib/preinit/02_sysinfo_fixup
@@ -0,0 +1,13 @@
+do_sysinfo_layerscape_fixup() {
+	[ -e /tmp/sysinfo/board_name ] || return
+	[ -e /proc/cmdline ] || return
+	cmdline=$(strings /proc/cmdline)
+	case "${cmdline}" in
+		*root=/dev/mmcblk*)
+			board="$(strings /tmp/sysinfo/board_name)-sdboot"
+			echo ${board} > /tmp/sysinfo/board_name
+		;;
+	esac
+}
+
+boot_hook_add preinit_main do_sysinfo_layerscape_fixup