Add --bootargs option to build_image.

This allows appending extra kernel command line parameters to
the ARM kernel command line on the Voguev210 boards.

BUG=None
TEST=Built image

Review URL: http://codereview.chromium.org/1694021

build_gpt.sh

@@ -21,6 +21,8 @@ DEFINE_string arch "" \
   "The target architecture (\"arm\" or \"x86\")."
 DEFINE_string board "$DEFAULT_BOARD" \
   "The board to build an image for."
+DEFINE_string arm_extra_bootargs "" \
+  "Additional command line options to pass to the ARM kernel."
 
 # Usage.
 FLAGS_HELP=$(cat <<EOF
@@ -114,7 +116,11 @@ install_gpt $OUTDEV $ROOTFS_IMG $KERNEL_IMG $STATEFUL_IMG $PMBRCODE $ESP_IMG
 if [[ "$ARCH" = "arm" ]]; then
   # assume /dev/mmcblk1. we could not get this from ${OUTDEV}
   DEVICE=1
-  MBR_SCRIPT_UIMG=$(make_arm_mbr ${START_KERN_A} ${NUM_KERN_SECTORS} ${DEVICE})
+  MBR_SCRIPT_UIMG=$(make_arm_mbr \
+    ${START_KERN_A} \
+    ${NUM_KERN_SECTORS} \
+    ${DEVICE} \
+    "${FLAGS_arm_extra_bootargs}")
   sudo dd bs=1 count=`stat --printf="%s" ${MBR_SCRIPT_UIMG}` \
      if="$MBR_SCRIPT_UIMG" of=${OUTDEV} conv=notrunc
 fi

build_image

@@ -43,6 +43,8 @@ DEFINE_boolean withtest $FLAGS_FALSE \
   "Include packages required for testing and prepare image for testing"
 DEFINE_string factory_server "" \
   "Build a factory install image pointing to given server."
+DEFINE_string arm_extra_bootargs "" \
+  "Additional command line options to pass to the ARM kernel."
 
 # Parse command line.
 FLAGS "$@" || exit 1
@@ -440,7 +442,11 @@ trap delete_prompt EXIT
 
 # Create the GPT-formatted image
 ${SCRIPTS_DIR}/build_gpt.sh \
-   --arch=${ARCH} --board=${FLAGS_board} "${OUTPUT_DIR}" "${OUTPUT_IMG}"
+  --arch=${ARCH} \
+  --board=${FLAGS_board} \
+  --arm_extra_bootargs="${FLAGS_arm_extra_bootargs}" \
+  "${OUTPUT_DIR}" \
+  "${OUTPUT_IMG}"
 
 # Clean up temporary files.
 rm -f "${ROOT_FS_IMG}" "${STATEFUL_IMG}" "${OUTPUT_DIR}/vmlinuz.image" \