swupdate-scripts: add a script to report the mmc / storage size

This script reports the size of the flash chip. Since it will report
a valid value for any block device it is booted from and to make clear
it is not a partition size, it is named storage-size.

The script will fail when the root partition is not a block device, e.g.
on the devices using ubi.

meta-venus/recipes-support/swupdate-scripts/files/storage-size.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+# only block devices are supported at the moment
+rootpart="$(mount | grep ' on / ' | awk '{print $1}')"
+parentdev=$(echo $rootpart | sed -n -r 's,^/dev/([a-zA-Z0-9]+)p[0-9]$,\1,p')
+if [ "$parentdev" = "" ]; then
+    echo "$rootdev doesn't seem to be a block device" 1>&2
+    exit 1
+fi
+
+sysdir="/sys/block/$parentdev"
+if [ ! -d $sysdir ]; then
+    echo "$sysdir doesn't exist" 1>&2
+    exit 1
+fi
+
+awk '{print $1*512}' "$sysdir/size"
+

meta-venus/recipes-support/swupdate-scripts/swupdate-scripts.bb

@@ -18,6 +18,7 @@ SRC_URI = " \
     file://set-feed.sh \
     file://set-swu-feed.sh \
     file://set-version.sh \
+    file://storage-size.sh \
 "
 
 S = "${WORKDIR}/sources"
@@ -37,6 +38,7 @@ do_install () {
     install -m 0755 ${UNPACKDIR}/set-feed.sh      ${DEST}/set-feed.sh
     install -m 0755 ${UNPACKDIR}/set-swu-feed.sh  ${DEST}/set-swu-feed.sh
     install -m 0755 ${UNPACKDIR}/set-version.sh   ${DEST}/set-version.sh
+    install -m 0755 ${UNPACKDIR}/storage-size.sh  ${DEST}/storage-size.sh
 
     DEST=${D}${sysconfdir}/init.d
     install -d ${DEST}