support booting from gzip compressed kernel image

U-Boot "booti" command can decompress gzip-compressed kernel
automatically, if a memory region has been specified as decompression
workspace through kernel_comp_addr_r & kernel_comp_size variables.

Switching generated images to include Image.gz frees up some space in
the 350MB initial rootfs and helps with journal errors during fist boot.

patches/u-boot-LSDK-21.08/0046-lx2160a_common-add-kernel-decompress-workspace-to-de.patch

+From 133c1f2434a6b8583feff488afda3dad10b1031c Mon Sep 17 00:00:00 2001
+From: Josua Mayer <josua@solid-run.com>
+Date: Wed, 14 Jun 2023 19:31:49 +0300
+Subject: [PATCH] lx2160a_common: add kernel decompress workspace to default
+ environment
+
+Signed-off-by: Josua Mayer <josua@solid-run.com>
+---
+ include/configs/lx2160a_common.h | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/include/configs/lx2160a_common.h b/include/configs/lx2160a_common.h
+index 556879375a..d0342b94a1 100644
+--- a/include/configs/lx2160a_common.h
++++ b/include/configs/lx2160a_common.h
+@@ -248,6 +248,8 @@ int select_i2c_ch_pca9547_n(int busnum, unsigned char ch);
+ #define EXTRA_ENV_SETTINGS			\
+ 	DEFAULT_FDT_FILE_ENV		\
+ 	"hwconfig=fsl_ddr:bank_intlv=auto\0"	\
++	"kernel_comp_addr_r=0x9f000000\0" \
++	"kernel_comp_size=0x10000000\0" \
+ 	"ramdisk_addr=0x85100000\0"		\
+ 	"ramdisk_addr_r=0x85100000\0"		\
+ 	"ramdisk_size=0x2000000\0"		\
+-- 
+2.35.3
+

runme.sh

@@ -544,6 +544,7 @@ mkdir -p $ROOTDIR/images/tmp/
 mkdir -p $ROOTDIR/images/tmp/boot
 make INSTALL_MOD_PATH=$ROOTDIR/images/tmp/ INSTALL_MOD_STRIP=1 modules_install
 cp $ROOTDIR/build/linux/arch/arm64/boot/Image $ROOTDIR/images/tmp/boot
+cp $ROOTDIR/build/linux/arch/arm64/boot/Image.gz $ROOTDIR/images/tmp/boot
 cp $ROOTDIR/build/linux/arch/arm64/boot/dts/freescale/fsl-lx216*.dtb $ROOTDIR/images/tmp/boot
 
 
@@ -570,7 +571,7 @@ cat > $ROOTDIR/images/tmp/extlinux/extlinux.conf << EOF
   menu title linux-lx2160a boot options
   label primary
     menu label primary kernel
-    linux /boot/Image
+    linux /boot/Image.gz
     fdtdir /boot/
     APPEND console=ttyAMA0,115200 earlycon=pl011,mmio32,0x21c0000 default_hugepagesz=1024m hugepagesz=1024m hugepages=2 pci=pcie_bus_perf root=PARTUUID=30303030-01 rw rootwait
 EOF
@@ -579,7 +580,7 @@ cp $ROOTDIR/build/$ROOTFS.ext4 $ROOTDIR/images/tmp/
 e2mkdir -G 0 -O 0 $ROOTDIR/images/tmp/$ROOTFS.ext4:extlinux
 e2cp -G 0 -O 0 $ROOTDIR/images/tmp/extlinux/extlinux.conf $ROOTDIR/images/tmp/$ROOTFS.ext4:extlinux/
 e2mkdir -G 0 -O 0 $ROOTDIR/images/tmp/$ROOTFS.ext4:boot
-e2cp -G 0 -O 0 $ROOTDIR/images/tmp/boot/Image $ROOTDIR/images/tmp/$ROOTFS.ext4:boot/
+e2cp -G 0 -O 0 $ROOTDIR/images/tmp/boot/Image.gz $ROOTDIR/images/tmp/$ROOTFS.ext4:boot/
 e2cp -G 0 -O 0 $ROOTDIR/images/tmp/boot/fsl-lx216*.dtb $ROOTDIR/images/tmp/$ROOTFS.ext4:boot/
 
 # Copy over kernel image