mvebu: add sdcard image creation script

Added gen_mvebu_sdcard_img.sh to facilitate creating an fixed-size sdcard image,
adding the bootloader and populating it with actual data.

Added the required rules for creating a 4GB sdcard image according to this layout:
p0: boot (fat32)
p1: rootfs (squashfs)
p2: rootfs_data (ext4)
This should be generic to any mvebu boards that can boot from block storage.

Added the new sdcard image to the Clearfog image profile.

Signed-off-by: Josua Mayer <josua.mayer97@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [cleanup]

config/Config-images.in

@@ -259,7 +259,7 @@ menu "Target Images"
 
 	config TARGET_ROOTFS_PARTSIZE
 		int "Root filesystem partition size (in MB)"
-		depends on GRUB_IMAGES || TARGET_ROOTFS_EXT4FS || TARGET_rb532
+		depends on GRUB_IMAGES || TARGET_ROOTFS_EXT4FS || TARGET_rb532 || TARGET_mvebu
 		default 48
 		help
 		  Select the root filesystem partition size.

target/linux/mvebu/image/Makefile

@@ -29,6 +29,38 @@ define Build/clearfog-bundle
 	gzip -9n -c $@.new > $@
 endef
 
+# SD-Card Images:
+# these values are optimized for a 4GB labeled sdcard that actually holds 7744512 sectors of 512 byte
+# MBR:            2048 sectors
+# Partition 1:   32768 sectors
+# Partition 2:   98304 sectors (configurable)
+# Partition 3: 7611392 sectors (configurable, depends on p2 size)
+
+define Build/boot-scr
+	rm -f $@.bootscript
+	mkimage -A arm -O linux -T script -C none -a 0 -e 0 -d boot.script $@.bootscript
+endef
+
+define Build/boot-img
+	rm -f $@.boot
+	mkfs.fat -C $@.boot 16384
+	$(foreach dts,$(DEVICE_DTS), mcopy -i $@.boot $(DTS_DIR)/$(dts).dtb ::$(dts).dtb)
+	mcopy -i $@.boot $(IMAGE_KERNEL) ::zImage
+	mcopy -i $@.boot $@.bootscript ::boot.scr
+endef
+
+define Build/sdcard-img
+	rm -rf $@ $@.rootfsdata $@.tmp
+	mkdir -p $@.tmp
+	ROOTFS_SIZE=$$(( $(CONFIG_TARGET_ROOTFS_PARTSIZE) * 1024 * 2 )); \
+	DATA_SIZE=$$(( 7709696 - ($(CONFIG_TARGET_ROOTFS_PARTSIZE) * 1024 * 2) )); \
+	make_ext4fs -J -l $$DATA_SIZE $@.rootfsdata $@.tmp && \
+	./gen_mvebu_sdcard_img.sh 7744512 $@ \
+		"$(BIN_DIR)/uboot-mvebu-clearfog/openwrt-mvebu-clearfog-u-boot-spl.kwb" \
+		c 32768 $@.boot \
+		83 $$ROOTFS_SIZE $(IMAGE_ROOTFS) \
+		83 $$DATA_SIZE $@.rootfsdata
+endef
 
 define Device/Default
   PROFILES := Default
@@ -150,9 +182,10 @@ define Device/armada-388-clearfog
   KERNEL_INSTALL := 1
   KERNEL := dtb | kernel-bin
   DEVICE_TITLE := SolidRun ClearFog
-  DEVICE_PACKAGES := uboot-mvebu-clearfog
+  DEVICE_PACKAGES := uboot-mvebu-clearfog kmod-fs-ext4
-  IMAGES := bundle.tar.gz
+  IMAGES := bundle.tar.gz sdcard.img.gz
   IMAGE/bundle.tar.gz := clearfog-bundle
+  IMAGE/sdcard.img.gz := boot-scr | boot-img | sdcard-img | gzip
   IMAGE_NAME = $$(IMAGE_PREFIX)-$$(2)
 endef
 TARGET_DEVICES += armada-388-clearfog

target/linux/mvebu/image/boot.script

@@ -0,0 +1,7 @@
+setenv bootargs console=ttyS0,115200n8 root=/dev/mmcblk0p2 rootfstype=squashfs rootwait overlay=/dev/mmcblk0p3
+setenv fdt_high 0x07a12000
+
+fatload mmc 0:1 0x02000000 zImage
+fatload mmc 0:1 0x05F00000 armada-388-clearfog.dtb
+
+bootz 0x02000000 - 0x05F00000

target/linux/mvebu/image/gen_mvebu_sdcard_img.sh

@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+#
+# Copyright (C) 2016 Josua Mayer
+# 
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+
+usage() {
+	echo "$0 <sectors> <outfile> <bootloader> [<type_partitionN> <sectors_partitionN> <img_partitionN>]?"
+}
+
+# always require first 3 arguments
+# then in pairs up to 8 more for a total of up to 4 partitions
+if [ $# -lt 3 ] || [ $# -gt 15 ] || [ $(($#%3)) -ne 0 ]; then
+	usage
+	exit 1
+fi
+
+set -e
+
+# parameters
+IMGSIZE=$1
+OUTFILE="$2"
+BOOTLOADER="$3"
+
+# calculate number of partitions from argument list
+NUMPARTS=$#
+((NUMPARTS=(NUMPARTS-3)/3))
+
+# find required applications
+FDISK=$(env PATH="/usr/local/sbin:/usr/sbin:/sbin:$PATH" which fdisk)
+
+# generate image file
+printf "Creating $OUTFILE from /dev/zero: "
+dd if=/dev/zero of="$OUTFILE" bs=512 count=1 >/dev/null
+printf "Done\n"
+
+# generate fdisk argument list
+printf "Generating fdisk argument list: "
+ARGSFILE=$(mktemp)
+
+# empty partition table
+printf "o\n" >> $ARGSFILE
+
+# actual partitions
+offset=2048
+for i in $(seq 1 1 $NUMPARTS); do
+	((n=3+3*i-2)); type=$(eval echo \${$n})
+	((n=3+3*i-1)); size=$(eval echo \${$n})
+	((end=offset+size-1))
+
+	printf "n\np\n%i\n\n%i\n" $i $end >> $ARGSFILE
+
+	# special case on first aprtition: fdisk wont ask which one
+	if [ $i -eq 1 ]; then
+		printf "t\n%s\n" $type >> $ARGSFILE
+	else
+		printf "t\n%i\n%s\n" $i $type >> $ARGSFILE
+	fi
+
+	# add this partitions size to offset for next partition
+	((offset=end+1))
+done
+
+# write and exit
+printf "w\n" >> $ARGSFILE
+
+printf "Done\n"
+
+# create real partition table using fdisk
+printf "Creating partition table: "
+cat $ARGSFILE | $FDISK "$OUTFILE" >/dev/null
+printf "Done\n"
+
+# remove temporary files
+printf "Cleaning up: "
+rm -f $ARGSFILE
+printf "Done\n"
+
+# install bootloader
+printf "Writing bootloader: "
+dd of="$OUTFILE" if="$BOOTLOADER" bs=512 seek=1 conv=notrunc 2>/dev/null
+printf "Done\n"
+
+# write partition data
+
+# offset of first partition is 2048
+offset=2048
+for i in $(seq 1 1 $NUMPARTS); do
+	((n=3+3*i-1)); size=$(eval echo \${$n})
+	((n=3+3*i));   img="$(eval echo \${$n})"
+
+	printf "Writing %s to partition %i: " "$img" $i
+	dd if="$img" of="$OUTFILE" bs=512 seek=$offset conv=notrunc 2>/dev/null
+	printf "Done\n"
+
+	# add this partitions size to offset for next partition
+	((offset=offset+size))
+done