image: add support for building FIT image with filesystem

Allow for single (external-data) FIT image to hold kernel, dtb and
squashfs. In that way, the bootloader verifies the system integrity
including the rootfs, because what's the point of checking that the
hash of the kernel is correct if it won't boot in case of squashfs
being corrupted? Better allow bootloader to check everything needed
to make it at least up to failsafe mode. As a positive side effect
this change also makes the sysupgrade process on nand potentially
much easier as it is now.
In short: mkimage has a parameter '-E' which allows generating FIT
images with 'external' data rather than embedding the data into the
device-tree blob itself. In this way, the FIT structure itself remains
small and can be parsed easily (rather than having to page around
megabytes of image content). This patch makes use of that and adds
support for adding sub-images of type 'filesystem' which are used to
store the squashfs. Now U-Boot can verify the whole OS and the new
partition parsers added in the Linux kernel can detect the filesystem
sub-images, create partitions for them, and select the active rootfs
volume based on the configuration in FIT (passing configuration via
device tree could be implemented easily at a later stage).

This new FIT partition parser works for NOR flash (on top of mtdblock),
NAND flash (on top of ubiblock) as well as classic block devices
(ie. eMMC, SDcard, SATA, NVME, ...).
It could even be used to mount such FIT images via `losetup -P` on a
user PC if this patch gets included in Linux upstream one day ;)

Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

10 files changed, 546 insertions, 44 deletions

diff --git a/include/image-commands.mk b/include/image-commands.mk
index 51e745958e..3377680a07 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -200,11 +200,13 @@ define Build/fit
 	$(TOPDIR)/scripts/mkits.sh \
 		-D $(DEVICE_NAME) -o $@.its -k $@ \
 		$(if $(word 2,$(1)),-d $(word 2,$(1))) -C $(word 1,$(1)) \
+		$(if $(findstring with-rootfs,$(word 3,$(1))),-r $(IMAGE_ROOTFS)) \
 		-a $(KERNEL_LOADADDR) -e $(if $(KERNEL_ENTRY),$(KERNEL_ENTRY),$(KERNEL_LOADADDR)) \
 		$(if $(DEVICE_FDT_NUM),-n $(DEVICE_FDT_NUM)) \
 		-c $(if $(DEVICE_DTS_CONFIG),$(DEVICE_DTS_CONFIG),"config@1") \
 		-A $(LINUX_KARCH) -v $(LINUX_VERSION)
-	PATH=$(LINUX_DIR)/scripts/dtc:$(PATH) mkimage -f $@.its $@.new
+	PATH=$(LINUX_DIR)/scripts/dtc:$(PATH) mkimage $(if $(findstring external,$(word 3,$(1))),\
+		-E -B 0x1000 $(if $(findstring static,$(word 3,$(1))),-p 0x1000)) -f $@.its $@.new
 	@mv $@.new $@
 endef
 
diff --git a/package/base-files/files/lib/upgrade/nand.sh b/package/base-files/files/lib/upgrade/nand.sh
index e6f58df4f5..7cf95c0139 100644
--- a/package/base-files/files/lib/upgrade/nand.sh
+++ b/package/base-files/files/lib/upgrade/nand.sh
@@ -3,13 +3,13 @@
 
 . /lib/functions.sh
 
-# 'kernel' partition on NAND contains the kernel
+# 'kernel' partition or UBI volume on NAND contains the kernel
 CI_KERNPART="${CI_KERNPART:-kernel}"
 
 # 'ubi' partition on NAND contains UBI
 CI_UBIPART="${CI_UBIPART:-ubi}"
 
-# 'rootfs' partition on NAND contains the rootfs
+# 'rootfs' UBI volume on NAND contains the rootfs
 CI_ROOTPART="${CI_ROOTPART:-rootfs}"
 
 ubi_mknod() {
@@ -117,9 +117,11 @@ nand_restore_config() {
 nand_upgrade_prepare_ubi() {
 	local rootfs_length="$1"
 	local rootfs_type="$2"
-	local has_kernel="${3:-0}"
+	local kernel_length="$3"
 	local has_env="${4:-0}"
 
+	[ -n "$rootfs_length" -o -n "$kernel_length" ] || return 1
+
 	local mtdnum="$( find_mtd_index "$CI_UBIPART" )"
 	if [ ! "$mtdnum" ]; then
 		echo "cannot find ubi mtd partition $CI_UBIPART"
@@ -148,23 +150,24 @@ nand_upgrade_prepare_ubi() {
 	local root_ubivol="$( nand_find_volume $ubidev $CI_ROOTPART )"
 	local data_ubivol="$( nand_find_volume $ubidev rootfs_data )"
 
-	# remove ubiblock device of rootfs
-	local root_ubiblk="ubiblock${root_ubivol:3}"
-	if [ "$root_ubivol" -a -e "/dev/$root_ubiblk" ]; then
-		echo "removing $root_ubiblk"
-		if ! ubiblock -r /dev/$root_ubivol; then
-			echo "cannot remove $root_ubiblk"
-			return 1;
+	local ubiblk ubiblkvol
+	for ubiblk in /dev/ubiblock*_? ; do
+		[ -e "$ubiblk" ] || continue
+		echo "removing ubiblock${ubiblk:13}"
+		ubiblkvol=ubi${ubiblk:13}
+		if ! ubiblock -r /dev/$ubiblkvol; then
+			echo "cannot remove $ubiblk"
+			return 1
 		fi
-	fi
+	done
 
 	# kill volumes
 	[ "$kern_ubivol" ] && ubirmvol /dev/$ubidev -N $CI_KERNPART || true
-	[ "$root_ubivol" ] && ubirmvol /dev/$ubidev -N $CI_ROOTPART || true
+	[ "$root_ubivol" -a "$root_ubivol" != "$kern_ubivol" ] && ubirmvol /dev/$ubidev -N $CI_ROOTPART || true
 	[ "$data_ubivol" ] && ubirmvol /dev/$ubidev -N rootfs_data || true
 
 	# update kernel
-	if [ "$has_kernel" = "1" ]; then
+	if [ -n "$kernel_length" ]; then
 		if ! ubimkvol /dev/$ubidev -N $CI_KERNPART -s $kernel_length; then
 			echo "cannot create kernel volume"
 			return 1;
@@ -172,15 +175,17 @@ nand_upgrade_prepare_ubi() {
 	fi
 
 	# update rootfs
-	local root_size_param
-	if [ "$rootfs_type" = "ubifs" ]; then
-		root_size_param="-m"
-	else
-		root_size_param="-s $rootfs_length"
-	fi
-	if ! ubimkvol /dev/$ubidev -N $CI_ROOTPART $root_size_param; then
-		echo "cannot create rootfs volume"
-		return 1;
+	if [ -n "$rootfs_length" ]; then
+		local root_size_param
+		if [ "$rootfs_type" = "ubifs" ]; then
+			root_size_param="-m"
+		else
+			root_size_param="-s $rootfs_length"
+		fi
+		if ! ubimkvol /dev/$ubidev -N $CI_ROOTPART $rootfs_size_param; then
+			echo "cannot create rootfs volume"
+			return 1;
+		fi
 	fi
 
 	# create rootfs_data for non-ubifs rootfs
@@ -232,7 +237,7 @@ nand_upgrade_ubinized() {
 nand_upgrade_ubifs() {
 	local rootfs_length=$( (cat $1 | wc -c) 2> /dev/null)
 
-	nand_upgrade_prepare_ubi "$rootfs_length" "ubifs" "0" "0"
+	nand_upgrade_prepare_ubi "$rootfs_length" "ubifs" "" ""
 
 	local ubidev="$( nand_find_ubi "$CI_UBIPART" )"
 	local root_ubivol="$(nand_find_volume $ubidev $CI_ROOTPART)"
@@ -241,39 +246,59 @@ nand_upgrade_ubifs() {
 	nand_do_upgrade_success
 }
 
+nand_upgrade_fit() {
+	local fit_file="$1"
+	local fit_length="$(wc -c < "$fit_file")"
+
+	nand_upgrade_prepare_ubi "" "" "$fit_length" "1"
+
+	local fit_ubidev="$(nand_find_ubi "$CI_UBIPART")"
+	local fit_ubivol="$(nand_find_volume $fit_ubidev "$CI_KERNPART")"
+	ubiupdatevol /dev/$fit_ubivol -s $fit_length $fit_file
+
+	nand_do_upgrade_success
+}
+
 nand_upgrade_tar() {
 	local tar_file="$1"
 	local kernel_mtd="$(find_mtd_index $CI_KERNPART)"
 
-	local board_dir=$(tar tf $tar_file | grep -m 1 '^sysupgrade-.*/$')
+	local board_dir=$(tar tf "$tar_file" | grep -m 1 '^sysupgrade-.*/$')
 	board_dir=${board_dir%/}
 
-	local kernel_length=$( (tar xf $tar_file ${board_dir}/kernel -O | wc -c) 2> /dev/null)
-	local rootfs_length=$( (tar xf $tar_file ${board_dir}/root -O | wc -c) 2> /dev/null)
+	kernel_length=$( (tar xf "$tar_file" ${board_dir}/kernel -O | wc -c) 2> /dev/null)
+	local has_rootfs=0
+	local rootfs_length
+	local rootfs_type
 
-	local rootfs_type="$(identify_tar "$tar_file" ${board_dir}/root)"
+	tar tf "$tar_file" ${board_dir}/root 1>/dev/null 2>/dev/null && has_rootfs=1
+	[ "$has_rootfs" = "1" ] && {
+		rootfs_length=$( (tar xf "$tar_file" ${board_dir}/root -O | wc -c) 2> /dev/null)
+		rootfs_type="$(identify_tar "$tar_file" ${board_dir}/root)"
+	}
 
 	local has_kernel=1
 	local has_env=0
 
 	[ "$kernel_length" != 0 -a -n "$kernel_mtd" ] && {
-		tar xf $tar_file ${board_dir}/kernel -O | mtd write - $CI_KERNPART
+		tar xf "$tar_file" ${board_dir}/kernel -O | mtd write - $CI_KERNPART
 	}
-	[ "$kernel_length" = 0 -o ! -z "$kernel_mtd" ] && has_kernel=0
+	[ "$kernel_length" = 0 -o ! -z "$kernel_mtd" ] && has_kernel=
 
-	nand_upgrade_prepare_ubi "$rootfs_length" "$rootfs_type" "$has_kernel" "$has_env"
+	nand_upgrade_prepare_ubi "$rootfs_length" "$rootfs_type" "${has_kernel:+$kernel_length}" "$has_env"
 
 	local ubidev="$( nand_find_ubi "$CI_UBIPART" )"
 	[ "$has_kernel" = "1" ] && {
-		local kern_ubivol="$(nand_find_volume $ubidev $CI_KERNPART)"
-		tar xf $tar_file ${board_dir}/kernel -O | \
+		local kern_ubivol="$( nand_find_volume $ubidev $CI_KERNPART )"
+		tar xf "$tar_file" ${board_dir}/kernel -O | \
 			ubiupdatevol /dev/$kern_ubivol -s $kernel_length -
 	}
 
-	local root_ubivol="$(nand_find_volume $ubidev $CI_ROOTPART)"
-	tar xf $tar_file ${board_dir}/root -O | \
-		ubiupdatevol /dev/$root_ubivol -s $rootfs_length -
-
+	[ "$has_rootfs" = "1" ] && {
+		local root_ubivol="$( nand_find_volume $ubidev $CI_ROOTPART )"
+		tar xf "$tar_file" ${board_dir}/root -O | \
+			ubiupdatevol /dev/$root_ubivol -s $rootfs_length -
+	}
 	nand_do_upgrade_success
 }
 
@@ -284,6 +309,7 @@ nand_do_upgrade() {
 	[ ! "$(find_mtd_index "$CI_UBIPART")" ] && CI_UBIPART="rootfs"
 
 	case "$file_type" in
+		"fit")		nand_upgrade_fit $1;;
 		"ubi")		nand_upgrade_ubinized $1;;
 		"ubifs")	nand_upgrade_ubifs $1;;
 		*)		nand_upgrade_tar $1;;
@@ -309,7 +335,7 @@ nand_do_platform_check() {
 	local control_length=$( (tar xf $tar_file sysupgrade-$board_name/CONTROL -O | wc -c) 2> /dev/null)
 	local file_type="$(identify $2)"
 
-	[ "$control_length" = 0 -a "$file_type" != "ubi" -a "$file_type" != "ubifs" ] && {
+	[ "$control_length" = 0 -a "$file_type" != "ubi" -a "$file_type" != "ubifs" -a "$file_type" != "fit" ] && {
 		echo "Invalid sysupgrade file."
 		return 1
 	}
diff --git a/scripts/mkits.sh b/scripts/mkits.sh
index bb629d6fca..59ff3a2d15 100755
--- a/scripts/mkits.sh
+++ b/scripts/mkits.sh
@@ -23,18 +23,24 @@ usage() {
 	printf "\n\t-c ==> set config name 'config'"
 	printf "\n\t-a ==> set load address to 'addr' (hex)"
 	printf "\n\t-e ==> set entry point to 'entry' (hex)"
+	printf "\n\t-f ==> set device tree compatible string"
 	printf "\n\t-v ==> set kernel version to 'version'"
 	printf "\n\t-k ==> include kernel image 'kernel'"
 	printf "\n\t-D ==> human friendly Device Tree Blob 'name'"
 	printf "\n\t-n ==> fdt unit-address 'address'"
 	printf "\n\t-d ==> include Device Tree Blob 'dtb'"
+	printf "\n\t-r ==> include RootFS blob 'rootfs'"
+	printf "\n\t-H ==> specify hash algo instead of SHA1"
 	printf "\n\t-o ==> create output file 'its_file'\n"
 	exit 1
 }
 
 FDTNUM=1
+ROOTFSNUM=1
+HASH=sha1
+LOADABLES=
 
-while getopts ":A:a:c:C:D:d:e:k:n:o:v:" OPTION
+while getopts ":A:a:c:C:D:d:e:f:k:n:o:v:r:S" OPTION
 do
 	case $OPTION in
 		A ) ARCH=$OPTARG;;
@@ -44,9 +50,12 @@ do
 		D ) DEVICE=$OPTARG;;
 		d ) DTB=$OPTARG;;
 		e ) ENTRY_ADDR=$OPTARG;;
+		f ) COMPATIBLE=$OPTARG;;
 		k ) KERNEL=$OPTARG;;
 		n ) FDTNUM=$OPTARG;;
 		o ) OUTPUT=$OPTARG;;
+		r ) ROOTFS=$OPTARG;;
+		S ) HASH=$OPTARG;;
 		v ) VERSION=$OPTARG;;
 		* ) echo "Invalid option passed to '$0' (options:$*)"
 		usage;;
@@ -62,11 +71,16 @@ fi
 
 ARCH_UPPER=$(echo "$ARCH" | tr '[:lower:]' '[:upper:]')
 
+if [ -n "${COMPATIBLE}" ]; then
+	COMPATIBLE_PROP="compatible = \"${COMPATIBLE}\";"
+fi
+
 # Conditionally create fdt information
 if [ -n "${DTB}" ]; then
 	FDT_NODE="
 		fdt@$FDTNUM {
 			description = \"${ARCH_UPPER} OpenWrt ${DEVICE} device tree blob\";
+			${COMPATIBLE_PROP}
 			data = /incbin/(\"${DTB}\");
 			type = \"flat_dt\";
 			arch = \"${ARCH}\";
@@ -75,13 +89,34 @@ if [ -n "${DTB}" ]; then
 				algo = \"crc32\";
 			};
 			hash@2 {
-				algo = \"sha1\";
+				algo = \"${HASH}\";
 			};
 		};
 "
 	FDT_PROP="fdt = \"fdt@$FDTNUM\";"
 fi
 
+if [ -n "${ROOTFS}" ]; then
+	dd if="${ROOTFS}" of="${ROOTFS}.pagesync" bs=4096 conv=sync
+	ROOTFS_NODE="
+		rootfs@$ROOTFSNUM {
+			description = \"${ARCH_UPPER} OpenWrt ${DEVICE} rootfs\";
+			${COMPATIBLE_PROP}
+			data = /incbin/(\"${ROOTFS}.pagesync\");
+			type = \"filesystem\";
+			arch = \"${ARCH}\";
+			compression = \"none\";
+			hash@1 {
+				algo = \"crc32\";
+			};
+			hash@2 {
+				algo = \"${HASH}\";
+			};
+		};
+"
+	LOADABLES="${LOADABLES:+$LOADABLES, }\"rootfs@${ROOTFSNUM}\""
+fi
+
 # Create a default, fully populated DTS file
 DATA="/dts-v1/;
 
@@ -103,18 +138,21 @@ DATA="/dts-v1/;
 				algo = \"crc32\";
 			};
 			hash@2 {
-				algo = \"sha1\";
+				algo = \"$HASH\";
 			};
 		};
 ${FDT_NODE}
+${ROOTFS_NODE}
 	};
 
 	configurations {
 		default = \"${CONFIG}\";
 		${CONFIG} {
-			description = \"OpenWrt\";
+			description = \"OpenWrt ${DEVICE}\";
 			kernel = \"kernel@1\";
 			${FDT_PROP}
+			${LOADABLES:+loadables = ${LOADABLES};}
+			${COMPATIBLE_PROP}
 		};
 	};
 };"
diff --git a/target/linux/generic/config-5.10 b/target/linux/generic/config-5.10
index d8c5017083..d88c0de17f 100644
--- a/target/linux/generic/config-5.10
+++ b/target/linux/generic/config-5.10
@@ -1871,6 +1871,7 @@ CONFIG_FIB_RULES=y
 # CONFIG_FIELDBUS_DEV is not set
 CONFIG_FILE_LOCKING=y
 # CONFIG_FIND_BIT_BENCHMARK is not set
+# CONFIG_FIT_PARTITION is not set
 # CONFIG_FIREWIRE is not set
 # CONFIG_FIREWIRE_NOSY is not set
 # CONFIG_FIREWIRE_SERIAL is not set
diff --git a/target/linux/generic/config-5.4 b/target/linux/generic/config-5.4
index 4ace100b01..9755c9658a 100644
--- a/target/linux/generic/config-5.4
+++ b/target/linux/generic/config-5.4
@@ -1665,6 +1665,7 @@ CONFIG_FILE_LOCKING=y
 # CONFIG_FIRMWARE_EDID is not set
 # CONFIG_FIRMWARE_IN_KERNEL is not set
 # CONFIG_FIRMWARE_MEMMAP is not set
+# CONFIG_FIT_PARTITION is not set
 # CONFIG_FIXED_PHY is not set
 CONFIG_FLATMEM=y
 CONFIG_FLATMEM_MANUAL=y
diff --git a/target/linux/generic/files/block/partitions/fit.c b/target/linux/generic/files/block/partitions/fit.c
new file mode 100644
index 0000000000..8ccbcf2fc2
--- /dev/null
+++ b/target/linux/generic/files/block/partitions/fit.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  fs/partitions/fit.c
+ *  Copyright (C) 2021  Daniel Golle
+ *
+ *  headers extracted from U-Boot mkimage sources
+ *  (C) Copyright 2008 Semihalf
+ *  (C) Copyright 2000-2005
+ *  Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ *  based on existing partition parsers
+ *  Copyright (C) 1991-1998  Linus Torvalds
+ *  Re-organised Feb 1998 Russell King
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/types.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
+
+#include "check.h"
+
+#define FIT_IMAGES_PATH		"/images"
+#define FIT_CONFS_PATH		"/configurations"
+
+/* hash/signature/key node */
+#define FIT_HASH_NODENAME	"hash"
+#define FIT_ALGO_PROP		"algo"
+#define FIT_VALUE_PROP		"value"
+#define FIT_IGNORE_PROP		"uboot-ignore"
+#define FIT_SIG_NODENAME	"signature"
+#define FIT_KEY_REQUIRED	"required"
+#define FIT_KEY_HINT		"key-name-hint"
+
+/* cipher node */
+#define FIT_CIPHER_NODENAME	"cipher"
+#define FIT_ALGO_PROP		"algo"
+
+/* image node */
+#define FIT_DATA_PROP		"data"
+#define FIT_DATA_POSITION_PROP	"data-position"
+#define FIT_DATA_OFFSET_PROP	"data-offset"
+#define FIT_DATA_SIZE_PROP	"data-size"
+#define FIT_TIMESTAMP_PROP	"timestamp"
+#define FIT_DESC_PROP		"description"
+#define FIT_ARCH_PROP		"arch"
+#define FIT_TYPE_PROP		"type"
+#define FIT_OS_PROP		"os"
+#define FIT_COMP_PROP		"compression"
+#define FIT_ENTRY_PROP		"entry"
+#define FIT_LOAD_PROP		"load"
+
+/* configuration node */
+#define FIT_KERNEL_PROP		"kernel"
+#define FIT_FILESYSTEM_PROP	"filesystem"
+#define FIT_RAMDISK_PROP	"ramdisk"
+#define FIT_FDT_PROP		"fdt"
+#define FIT_LOADABLE_PROP	"loadables"
+#define FIT_DEFAULT_PROP	"default"
+#define FIT_SETUP_PROP		"setup"
+#define FIT_FPGA_PROP		"fpga"
+#define FIT_FIRMWARE_PROP	"firmware"
+#define FIT_STANDALONE_PROP	"standalone"
+
+#define FIT_MAX_HASH_LEN	HASH_MAX_DIGEST_SIZE
+
+int fit_partition(struct parsed_partitions *state)
+{
+	struct address_space *mapping = state->bdev->bd_inode->i_mapping;
+	struct page *page = read_mapping_page(mapping, 0, NULL);
+	void *fit, *init_fit;
+	struct partition_meta_info *info;
+	char tmp[sizeof(info->volname)];
+	u64 dsize, dsectors;
+	u32 size, image_pos, image_len;
+	const u32 *image_offset_be, *image_len_be, *image_pos_be;
+	int ret = 1, node, images, config, slot;
+	const char *image_name, *image_type, *image_description, *config_default,
+		*config_description, *config_loadables;
+	int image_name_len, image_type_len, image_description_len, config_default_len,
+		config_description_len, config_loadables_len;
+	sector_t start_sect, nr_sects;
+	size_t label_min;
+
+	if (!page)
+		return -ENOMEM;
+
+	init_fit = page_address(page);
+
+	if (!init_fit) {
+		put_page(page);
+		return -EFAULT;
+	}
+
+	if (fdt_check_header(init_fit)) {
+		put_page(page);
+		return 0;
+	}
+
+	dsectors = get_capacity(state->bdev->bd_disk);
+	dsize = dsectors << SECTOR_SHIFT;
+	printk(KERN_DEBUG "FIT: volume size: %llu sectors (%llu bytes)\n", dsectors, dsize);
+
+	size = fdt_totalsize(init_fit);
+	printk(KERN_DEBUG "FIT: FDT structure size: %u bytes\n", size);
+	if (size > PAGE_SIZE) {
+		printk(KERN_ERR "FIT: FDT structure beyond page boundaries, use 'mkimage -E ...'!\n");
+		put_page(page);
+		return -ENOTSUPP;
+	}
+
+	if (size >= dsize) {
+		put_page(page);
+		state->access_beyond_eod = (size >= dsize);
+		return 0;
+	}
+
+	fit = kmemdup(init_fit, size, GFP_KERNEL);
+	put_page(page);
+	if (!fit)
+		return -ENOMEM;
+
+	config = fdt_path_offset(fit, FIT_CONFS_PATH);
+	if (config < 0) {
+		printk(KERN_ERR "FIT: Cannot find %s node: %d\n", FIT_CONFS_PATH, images);
+		ret = -ENOENT;
+		goto ret_out;
+	}
+
+	config_default = fdt_getprop(fit, config, FIT_DEFAULT_PROP, &config_default_len);
+
+	if (!config_default) {
+		printk(KERN_ERR "FIT: Cannot find default configuration\n");
+		ret = -ENOENT;
+		goto ret_out;
+	}
+
+	node = fdt_subnode_offset(fit, config, config_default);
+	if (node < 0) {
+		printk(KERN_ERR "FIT: Cannot find %s node: %d\n", config_default, node);
+		ret = -ENOENT;
+		goto ret_out;
+	}
+
+	config_description = fdt_getprop(fit, node, FIT_DESC_PROP, &config_description_len);
+	config_loadables = fdt_getprop(fit, node, FIT_LOADABLE_PROP, &config_loadables_len);
+
+	printk(KERN_DEBUG "FIT: Default configuration: %s%s%s%s\n", config_default,
+		config_description?" (":"", config_description?:"", config_description?")":"");
+
+	images = fdt_path_offset(fit, FIT_IMAGES_PATH);
+	if (images < 0) {
+		printk(KERN_ERR "FIT: Cannot find %s node: %d\n", FIT_IMAGES_PATH, images);
+		ret = -EINVAL;
+		goto ret_out;
+	}
+
+	slot = 1;
+	fdt_for_each_subnode(node, fit, images) {
+		image_name = fdt_get_name(fit, node, &image_name_len);
+		image_type = fdt_getprop(fit, node, FIT_TYPE_PROP, &image_type_len);
+		image_offset_be = fdt_getprop(fit, node, FIT_DATA_OFFSET_PROP, NULL);
+		image_pos_be = fdt_getprop(fit, node, FIT_DATA_POSITION_PROP, NULL);
+		image_len_be = fdt_getprop(fit, node, FIT_DATA_SIZE_PROP, NULL);
+		if (!image_name || !image_type || !image_len_be)
+			continue;
+
+		image_len = be32_to_cpu(*image_len_be);
+		if (!image_len)
+			continue;
+
+		if (image_offset_be)
+			image_pos = be32_to_cpu(*image_offset_be) + size;
+		else if (image_pos_be)
+			image_pos = be32_to_cpu(*image_pos_be);
+		else
+			continue;
+
+		image_description = fdt_getprop(fit, node, FIT_DESC_PROP, &image_description_len);
+
+		printk(KERN_DEBUG "FIT: %16s sub-image 0x%08x - 0x%08x '%s' %s%s%s\n",
+			image_type, image_pos, image_pos + image_len, image_name,
+			image_description?"(":"", image_description?:"", image_description?") ":"");
+
+		if (strcmp(image_type, FIT_FILESYSTEM_PROP))
+			continue;
+
+		if (image_pos & ((1 << PAGE_SHIFT)-1)) {
+			printk(KERN_ERR "FIT: image %s start not aligned to page boundaries, skipping\n", image_name);
+			continue;
+		}
+
+		if (image_len & ((1 << PAGE_SHIFT)-1)) {
+			printk(KERN_ERR "FIT: sub-image %s end not aligned to page boundaries, skipping\n", image_name);
+			continue;
+		}
+
+		start_sect = image_pos >> SECTOR_SHIFT;
+		nr_sects = image_len >> SECTOR_SHIFT;
+
+		if (start_sect + nr_sects > dsectors) {
+			state->access_beyond_eod = 1;
+			continue;
+		}
+
+		put_partition(state, slot, start_sect, nr_sects);
+		state->parts[slot].flags = 0;
+		info = &state->parts[slot].info;
+
+		label_min = min_t(int, sizeof(info->volname) - 1, image_name_len);
+		strncpy(info->volname, image_name, label_min);
+		info->volname[label_min] = '\0';
+
+		snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
+		strlcat(state->pp_buf, tmp, PAGE_SIZE);
+
+		state->parts[slot].has_info = true;
+
+		if (config_loadables && !strcmp(image_name, config_loadables)) {
+			printk(KERN_DEBUG "FIT: selecting configured loadable %s to be root filesystem\n", image_name);
+			state->parts[slot].flags |= ADDPART_FLAG_ROOTDEV;
+		}
+
+		++slot;
+	}
+
+ret_out:
+	kfree(fit);
+	return ret;
+}
diff --git a/target/linux/generic/hack-5.10/400-block-fit-partition-parser.patch b/target/linux/generic/hack-5.10/400-block-fit-partition-parser.patch
new file mode 100644
index 0000000000..9eaf8637d0
--- /dev/null
+++ b/target/linux/generic/hack-5.10/400-block-fit-partition-parser.patch
@@ -0,0 +1,96 @@
+--- a/block/blk.h
++++ b/block/blk.h
+@@ -357,6 +357,7 @@ char *disk_name(struct gendisk *hd, int
+ #define ADDPART_FLAG_NONE	0
+ #define ADDPART_FLAG_RAID	1
+ #define ADDPART_FLAG_WHOLEDISK	2
++#define ADDPART_FLAG_ROOTDEV	4
+ void delete_partition(struct hd_struct *part);
+ int bdev_add_partition(struct block_device *bdev, int partno,
+ 		sector_t start, sector_t length);
+--- a/block/partitions/Kconfig
++++ b/block/partitions/Kconfig
+@@ -101,6 +101,13 @@ config ATARI_PARTITION
+ 	  Say Y here if you would like to use hard disks under Linux which
+ 	  were partitioned under the Atari OS.
+ 
++config FIT_PARTITION
++	bool "Flattened-Image-Tree (FIT) partition support" if PARTITION_ADVANCED
++	default n
++	help
++	  Say Y here if your system needs to mount the filesystem part of
++	  a Flattened-Image-Tree (FIT) image commonly used with Das U-Boot.
++
+ config IBM_PARTITION
+ 	bool "IBM disk label and partition support"
+ 	depends on PARTITION_ADVANCED && S390
+--- a/block/partitions/Makefile
++++ b/block/partitions/Makefile
+@@ -8,6 +8,7 @@ obj-$(CONFIG_ACORN_PARTITION) += acorn.o
+ obj-$(CONFIG_AMIGA_PARTITION) += amiga.o
+ obj-$(CONFIG_ATARI_PARTITION) += atari.o
+ obj-$(CONFIG_AIX_PARTITION) += aix.o
++obj-$(CONFIG_FIT_PARTITION) += fit.o
+ obj-$(CONFIG_CMDLINE_PARTITION) += cmdline.o
+ obj-$(CONFIG_MAC_PARTITION) += mac.o
+ obj-$(CONFIG_LDM_PARTITION) += ldm.o
+--- a/block/partitions/check.h
++++ b/block/partitions/check.h
+@@ -58,6 +58,7 @@ int amiga_partition(struct parsed_partit
+ int atari_partition(struct parsed_partitions *state);
+ int cmdline_partition(struct parsed_partitions *state);
+ int efi_partition(struct parsed_partitions *state);
++int fit_partition(struct parsed_partitions *state);
+ int ibm_partition(struct parsed_partitions *);
+ int karma_partition(struct parsed_partitions *state);
+ int ldm_partition(struct parsed_partitions *state);
+--- a/block/partitions/core.c
++++ b/block/partitions/core.c
+@@ -10,6 +10,8 @@
+ #include <linux/vmalloc.h>
+ #include <linux/blktrace_api.h>
+ #include <linux/raid/detect.h>
++#include <linux/root_dev.h>
++
+ #include "check.h"
+ 
+ static int (*check_part[])(struct parsed_partitions *) = {
+@@ -46,6 +48,9 @@ static int (*check_part[])(struct parsed
+ #ifdef CONFIG_EFI_PARTITION
+ 	efi_partition,		/* this must come before msdos */
+ #endif
++#ifdef CONFIG_FIT_PARTITION
++	fit_partition,
++#endif
+ #ifdef CONFIG_SGI_PARTITION
+ 	sgi_partition,
+ #endif
+@@ -694,6 +699,9 @@ static bool blk_add_partition(struct gen
+ 	    (state->parts[p].flags & ADDPART_FLAG_RAID))
+ 		md_autodetect_dev(part_to_dev(part)->devt);
+ 
++	if ((state->parts[p].flags & ADDPART_FLAG_ROOTDEV) && ROOT_DEV == 0)
++		ROOT_DEV = part_to_dev(part)->devt;
++
+ 	return true;
+ }
+ 
+--- a/drivers/mtd/ubi/block.c
++++ b/drivers/mtd/ubi/block.c
+@@ -396,7 +396,7 @@ int ubiblock_create(struct ubi_volume_in
+ 	dev->leb_size = vi->usable_leb_size;
+ 
+ 	/* Initialize the gendisk of this ubiblock device */
+-	gd = alloc_disk(1);
++	gd = alloc_disk(0);
+ 	if (!gd) {
+ 		pr_err("UBI: block: alloc_disk failed\n");
+ 		ret = -ENODEV;
+@@ -413,6 +413,7 @@ int ubiblock_create(struct ubi_volume_in
+ 		goto out_put_disk;
+ 	}
+ 	gd->private_data = dev;
++	gd->flags |= GENHD_FL_EXT_DEVT;
+ 	sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
+ 	set_capacity(gd, disk_capacity);
+ 	dev->gd = gd;
diff --git a/target/linux/generic/hack-5.4/400-block-fit-partition-parser.patch b/target/linux/generic/hack-5.4/400-block-fit-partition-parser.patch
new file mode 100644
index 0000000000..13cf5e8ca0
--- /dev/null
+++ b/target/linux/generic/hack-5.4/400-block-fit-partition-parser.patch
@@ -0,0 +1,99 @@
+--- a/block/partitions/Kconfig
++++ b/block/partitions/Kconfig
+@@ -101,6 +101,13 @@ config ATARI_PARTITION
+ 	  Say Y here if you would like to use hard disks under Linux which
+ 	  were partitioned under the Atari OS.
+ 
++config FIT_PARTITION
++	bool "Flattened-Image-Tree (FIT) partition support" if PARTITION_ADVANCED
++	default n
++	help
++	  Say Y here if your system needs to mount the filesystem part of
++	  a Flattened-Image-Tree (FIT) image commonly used with Das U-Boot.
++
+ config IBM_PARTITION
+ 	bool "IBM disk label and partition support"
+ 	depends on PARTITION_ADVANCED && S390
+--- a/block/partitions/Makefile
++++ b/block/partitions/Makefile
+@@ -9,6 +9,7 @@ obj-$(CONFIG_ACORN_PARTITION) += acorn.o
+ obj-$(CONFIG_AMIGA_PARTITION) += amiga.o
+ obj-$(CONFIG_ATARI_PARTITION) += atari.o
+ obj-$(CONFIG_AIX_PARTITION) += aix.o
++obj-$(CONFIG_FIT_PARTITION) += fit.o
+ obj-$(CONFIG_CMDLINE_PARTITION) += cmdline.o
+ obj-$(CONFIG_MAC_PARTITION) += mac.o
+ obj-$(CONFIG_LDM_PARTITION) += ldm.o
+--- a/drivers/mtd/ubi/block.c
++++ b/drivers/mtd/ubi/block.c
+@@ -396,7 +396,7 @@ int ubiblock_create(struct ubi_volume_in
+ 	dev->leb_size = vi->usable_leb_size;
+ 
+ 	/* Initialize the gendisk of this ubiblock device */
+-	gd = alloc_disk(1);
++	gd = alloc_disk(0);
+ 	if (!gd) {
+ 		pr_err("UBI: block: alloc_disk failed\n");
+ 		ret = -ENODEV;
+@@ -413,6 +413,7 @@ int ubiblock_create(struct ubi_volume_in
+ 		goto out_put_disk;
+ 	}
+ 	gd->private_data = dev;
++	gd->flags |= GENHD_FL_EXT_DEVT;
+ 	sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
+ 	set_capacity(gd, disk_capacity);
+ 	dev->gd = gd;
+--- a/block/partition-generic.c
++++ b/block/partition-generic.c
+@@ -18,6 +18,7 @@
+ #include <linux/ctype.h>
+ #include <linux/genhd.h>
+ #include <linux/blktrace_api.h>
++#include <linux/root_dev.h>
+ 
+ #include "partitions/check.h"
+ 
+@@ -634,6 +635,8 @@ rescan:
+ 		if (state->parts[p].flags & ADDPART_FLAG_RAID)
+ 			md_autodetect_dev(part_to_dev(part)->devt);
+ #endif
++		if ((state->parts[p].flags & ADDPART_FLAG_ROOTDEV) && ROOT_DEV == 0)
++			ROOT_DEV = part_to_dev(part)->devt;
+ 	}
+ 	free_partitions(state);
+ 	return 0;
+--- a/block/partitions/check.c
++++ b/block/partitions/check.c
+@@ -33,6 +33,7 @@
+ #include "ibm.h"
+ #include "ultrix.h"
+ #include "efi.h"
++#include "fit.h"
+ #include "karma.h"
+ #include "sysv68.h"
+ #include "cmdline.h"
+@@ -73,6 +74,9 @@ static int (*check_part[])(struct parsed
+ #ifdef CONFIG_EFI_PARTITION
+ 	efi_partition,		/* this must come before msdos */
+ #endif
++#ifdef CONFIG_FIT_PARTITION
++	fit_partition,
++#endif
+ #ifdef CONFIG_SGI_PARTITION
+ 	sgi_partition,
+ #endif
+--- a/include/linux/genhd.h
++++ b/include/linux/genhd.h
+@@ -614,6 +614,7 @@ struct unixware_disklabel {
+ #define ADDPART_FLAG_NONE	0
+ #define ADDPART_FLAG_RAID	1
+ #define ADDPART_FLAG_WHOLEDISK	2
++#define ADDPART_FLAG_ROOTDEV	4
+ 
+ extern int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
+ extern void blk_free_devt(dev_t devt);
+--- /dev/null
++++ b/block/partitions/fit.h
+@@ -0,0 +1,2 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++int fit_partition(struct parsed_partitions *);
diff --git a/target/linux/generic/pending-5.10/491-ubi-auto-create-ubiblock-device-for-rootfs.patch b/target/linux/generic/pending-5.10/491-ubi-auto-create-ubiblock-device-for-rootfs.patch
index e5ee2c8656..a2b48fd4fc 100644
--- a/target/linux/generic/pending-5.10/491-ubi-auto-create-ubiblock-device-for-rootfs.patch
+++ b/target/linux/generic/pending-5.10/491-ubi-auto-create-ubiblock-device-for-rootfs.patch
@@ -8,7 +8,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 
 --- a/drivers/mtd/ubi/block.c
 +++ b/drivers/mtd/ubi/block.c
-@@ -652,6 +652,44 @@ static void __init ubiblock_create_from_
+@@ -652,6 +652,47 @@ static void __init ubiblock_create_from_
  	}
  }
  
@@ -33,6 +33,9 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 +	for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++) {
 +		desc = ubi_open_volume_nm(ubi_num, "rootfs", UBI_READONLY);
 +		if (IS_ERR(desc))
++			desc = ubi_open_volume_nm(ubi_num, "fit", UBI_READONLY);;
++
++		if (IS_ERR(desc))
 +			continue;
 +
 +		ubi_get_volume_info(desc, &vi);
diff --git a/target/linux/generic/pending-5.4/491-ubi-auto-create-ubiblock-device-for-rootfs.patch b/target/linux/generic/pending-5.4/491-ubi-auto-create-ubiblock-device-for-rootfs.patch
index 61fcbac92e..88d609d996 100644
--- a/target/linux/generic/pending-5.4/491-ubi-auto-create-ubiblock-device-for-rootfs.patch
+++ b/target/linux/generic/pending-5.4/491-ubi-auto-create-ubiblock-device-for-rootfs.patch
@@ -8,7 +8,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 
 --- a/drivers/mtd/ubi/block.c
 +++ b/drivers/mtd/ubi/block.c
-@@ -652,6 +652,44 @@ static void __init ubiblock_create_from_
+@@ -652,6 +652,47 @@ static void __init ubiblock_create_from_
  	}
  }
  
@@ -33,6 +33,9 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 +	for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++) {
 +		desc = ubi_open_volume_nm(ubi_num, "rootfs", UBI_READONLY);
 +		if (IS_ERR(desc))
++			desc = ubi_open_volume_nm(ubi_num, "fit", UBI_READONLY);;
++
++		if (IS_ERR(desc))
 +			continue;
 +
 +		ubi_get_volume_info(desc, &vi);