bcm4908: support "rootfs_data" on U-Boot devices

1. Create "rootfs_data" dynamicaly

U-Boot firmware images can contain only 2 UBI volumes: bootfs (container
with U-Boot + kernel + DTBs) and rootfs (e.g. squashfs). There is no way
to include "rootfs_data" UBI volume or make firmware file tell U-Boot to
create one.

For that reason "rootfs_data" needs to be created dynamically. Use
preinit script to handle that. Fire it right before "mount_root" one.

2. Relate "rootfs_data" to flashed firmware

As already explained flashing new firmware with U-Boot will do nothing
to the "rootfs_data". It could result in new firmware reusing old
"rootfs_data" overlay UBI volume and its file. Users expect a clean
state after flashing firmware (even if flashing the same one).

Solve that by reading flash counter of running firmware and storing it
in "rootfs_data" UBI volume. Every mismatch will result in wiping old
data.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 14 insertions, 13 deletions

diff --git a/target/linux/bcm4908/base-files/lib/upgrade/platform.sh b/target/linux/bcm4908/base-files/lib/upgrade/platform.sh
index 1b94801fb0..0974331801 100644
--- a/target/linux/bcm4908/base-files/lib/upgrade/platform.sh
+++ b/target/linux/bcm4908/base-files/lib/upgrade/platform.sh
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
 
-RAMFS_COPY_BIN="bcm4908img expr grep fdtget fw_printenv fw_setenv tr"
+. /lib/functions/bcm4908.sh
+
+RAMFS_COPY_BIN="bcm4908img expr grep ln fdtget fw_printenv fw_setenv readlink tr"
 
 PART_NAME=firmware
 
@@ -134,17 +136,7 @@ platform_pkgtb_get_image() {
 	}
 }
 
-platform_pkgtb_setup_env_config() {
-	local size=$((0x$(get_hex_u32_le /dev/ubi0_1 4)))
-
-	dd if=/dev/ubi0_1 of=/tmp/env.head count=8 iflag=count_bytes
-	dd if=/dev/ubi0_1 of=/tmp/env.body skip=8 iflag=skip_bytes
-	printf "%s\t0x%x\t0x%x\t0x%x" "/tmp/env.body" 0x0 $size $size > /tmp/env.config
-}
-
 platform_pkgtb_get_upgrade_index() {
-	platform_pkgtb_setup_env_config
-
 	case "$(fw_printenv -l /tmp -n -c /tmp/env.config COMMITTED)" in
 		1) echo 2;;
 		2) echo 1;;
@@ -160,8 +152,6 @@ platform_pkgtb_commit() {
 	local seq2
 	local tmp
 
-	platform_pkgtb_setup_env_config
-
 	# Read current values
 	for valid in $(fw_printenv -l /tmp -n -c /tmp/env.config VALID | tr ',' ' '); do
 		case "$valid" in
@@ -272,11 +262,20 @@ platform_check_image() {
 # upgrade
 #
 
+platform_pkgtb_clean_rootfs_data() {
+	local ubidev=$(nand_find_ubi $CI_UBIPART)
+	local ubivol="$(nand_find_volume $ubidev rootfs_data)"
+
+	bcm4908_verify_rootfs_data "$ubivol"
+}
+
 platform_do_upgrade_pkgtb() {
 	local cmd="${2:-cat}"
 	local size
 	local idx bootfs_id rootfs_id
 
+	bcm4908_pkgtb_setup_env_config
+
 	idx=$(platform_pkgtb_get_upgrade_index)
 	case "$idx" in
 		1) bootfs_id=3; rootfs_id=4;;
@@ -295,6 +294,8 @@ platform_do_upgrade_pkgtb() {
 
 	platform_pkgtb_commit $idx
 
+	CI_UBIPART="image"
+	platform_pkgtb_clean_rootfs_data
 	nand_do_upgrade_success
 }