update/blobs/*: simplify mrc.bin handling

mrc.bin is now handled by include/mrc.sh, adapted
from now-deleted script/update/blobs/mrc

much of the logic has been re-written or adapted for
inside script/update/blobs/download

mrc links/hashes now defined in config/blobs/sources

the new code is simpler (and smaller). in addition,
lbmk can now easily handle mrc.bin files for other
platforms such as broadwell. watch this space.

the full .zip download is now cached, like with other
vendor downloads. this means it won't be re-downloaded
if it was already downloaded before.

Signed-off-by: Leah Rowe <leah@libreboot.org>

2 files changed, 85 insertions, 2 deletions

diff --git a/include/blobutil.sh b/include/blobutil.sh
index 182ddf14..b85b8644 100755
--- a/include/blobutil.sh
+++ b/include/blobutil.sh
@@ -10,7 +10,8 @@ appdir="${blobdir}/app"
 setvars="EC_url=\"\""
 for x in EC_url_bkup EC_hash DL_hash DL_url DL_url_bkup E6400_VGA_DL_hash \
     E6400_VGA_DL_url E6400_VGA_DL_url_bkup E6400_VGA_offset E6400_VGA_romname \
-    SCH5545EC_DL_url SCH5545EC_DL_url_bkup SCH5545EC_DL_hash; do
+    SCH5545EC_DL_url SCH5545EC_DL_url_bkup SCH5545EC_DL_hash MRC_url \
+    MRC_url_bkup MRC_hash MRC_board; do
 	setvars="${setvars}; ${x}=\"\""
 done
 
@@ -40,7 +41,7 @@ for x in _me_destination _gbe_destination _ifd_destination \
     CONFIG_KBC1126_FW1_OFFSET CONFIG_KBC1126_FW2 CONFIG_KBC1126_FW2_OFFSET \
     CONFIG_VGA_BIOS_FILE CONFIG_VGA_BIOS_ID CONFIG_GBE_BIN_PATH \
     CONFIG_INCLUDE_SMSC_SCH5545_EC_FW CONFIG_SMSC_SCH5545_EC_FW_FILE \
-    CONFIG_IFD_BIN_PATH; do
+    CONFIG_IFD_BIN_PATH CONFIG_MRC_FILE; do
 	setvars="${setvars}; ${x}=\"\""
 done
 
diff --git a/include/mrc.sh b/include/mrc.sh
new file mode 100755
index 00000000..b9345b92
--- /dev/null
+++ b/include/mrc.sh
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Logic based on util/chromeos/crosfirmware.sh in coreboot cfc26ce278.
+# Modifications in this version are Copyright 2021 and 2023 Leah Rowe.
+# Original copyright detailed in repo: https://review.coreboot.org/coreboot/
+
+extract_mrc()
+{
+	[ -z "${MRC_board}" ] && err "extract_mrc $MRC_hash: MRC_board not set"
+	[ -z "${CONFIG_MRC_FILE}" ] && \
+		err "extract_mrc $MRC_hash: CONFIG_MRC_FILE not set"
+
+	_file="${MRC_url##*/}"
+	_file="${_file%.zip}"
+	_mrc_destination="${CONFIG_MRC_FILE#../../}"
+	mkdirs "${_mrc_destination}" "extract_mrc" || return 0
+
+	(
+	cd "${appdir}" || err "extract_mrc: !cd ${appdir}"
+	extract_partition ROOT-A "${_file}" root-a.ext2
+	extract_shellball root-a.ext2 chromeos-firmwareupdate-${MRC_board}
+	extract_coreboot chromeos-firmwareupdate-${MRC_board}
+	)
+
+	"${cbfstool}" "${appdir}/"coreboot-*.bin extract -n mrc.bin \
+	    -f "${_mrc_destination}" -r RO_SECTION || \
+	    err "extract_mrc: could not fetch mrc.bin"
+}
+
+extract_partition()
+{
+	NAME=${1}
+	FILE=${2}
+	ROOTFS=${3}
+	_bs=1024
+
+	printf "Extracting ROOT-A partition\n"
+	ROOTP=$( printf "unit\nB\nprint\nquit\n" | \
+	    parted "${FILE}" 2>/dev/null | grep "${NAME}" )
+
+	START=$(( $( echo ${ROOTP} | cut -f2 -d\ | tr -d "B" ) ))
+	SIZE=$(( $( echo ${ROOTP} | cut -f4 -d\ | tr -d "B" ) ))
+
+	dd if="${FILE}" of="${ROOTFS}" bs=${_bs} skip=$(( ${START} / ${_bs} )) \
+	    count=$(( ${SIZE} / ${_bs} )) || \
+	    err "extract_partition: can't extract root file system"
+}
+
+extract_shellball()
+{
+	ROOTFS=${1}
+	SHELLBALL=${2}
+
+	printf "Extracting chromeos-firmwareupdate\n"
+	printf "cd /usr/sbin\ndump chromeos-firmwareupdate ${SHELLBALL}\nquit" \
+	    | debugfs "${ROOTFS}" || err "extract_shellball: debugfs"
+}
+
+extract_coreboot()
+{
+	_shellball=${1}
+	_unpacked=$( mktemp -d )
+
+	printf "Extracting coreboot image\n"
+	[ -f "${_shellball}" ] || \
+	    err "extract_coreboot: shellball missing in google cros image"
+	sh "${_shellball}" --unpack "${_unpacked}" || \
+	    err "extract_coreboot: shellball exits with non-zero status"
+
+	# TODO: audit the f* out of that shellball, for each mrc version.
+	# it has to be updated for each mrc update. we should ideally
+	# implement the functionality ourselves.
+
+	[ -f "${_unpacked}/VERSION" ] || \
+	    err "extract_coreboot: VERSION file missing on google coreboot rom"
+
+	_version=$( cat "${_unpacked}/VERSION" | grep BIOS\ version: | \
+	    cut -f2 -d: | tr -d \  )
+
+	cp "${_unpacked}/bios.bin" "coreboot-${_version}.bin" || \
+	    err "extract_coreboot: cannot copy google cros rom"
+}