ubifs: Add UBI image generation support.

UBI images are generated from UBIFS one (with ubinize tool) and are used by
bootloaders (eg U-Boot) to write UBIFS images directly on bare NAND FLASH
(see http://www.linux-mtd.infradead.org/faq/ubi.html).

[Peter: tweak help text]
Signed-off-by: Julien Boibessot <julien.boibessot@armadeus.com>
Signed-off-by: Nicolas Colombain <nicolas.colombain@armadeus.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

fs/ubifs/Config.in

@@ -77,3 +77,24 @@ config BR2_TARGET_ROOTFS_UBIFS_LZMA
 
 endchoice
 
+config BR2_TARGET_ROOTFS_UBI
+	depends on BR2_TARGET_ROOTFS_UBIFS
+	bool "Embed into an UBI image"
+	help
+	  Build an ubi image from the ubifs one (with ubinize).
+
+config BR2_TARGET_ROOTFS_UBI_PEBSIZE
+	hex "UBI physical erase block size"
+	depends on BR2_TARGET_ROOTFS_UBI
+	default 0x20000
+	help
+	  Tells ubinize the physical eraseblock size of the flash chip
+	  the ubi image is created for.
+
+config BR2_TARGET_ROOTFS_UBI_SUBSIZE
+	int "UBI sub-page size"
+	depends on BR2_TARGET_ROOTFS_UBI
+	default 512
+	help
+	  Tells ubinize that the flash supports sub-pages and the sub-page
+	  size. Use 0 if subpages are not supported on flash chip.

fs/ubifs/ubi.mk

@@ -0,0 +1,23 @@
+#############################################################
+#
+# Embed the ubifs image into an ubi one
+#
+#############################################################
+
+UBI_UBINIZE_OPTS := -m $(BR2_TARGET_ROOTFS_UBIFS_MINIOSIZE)
+UBI_UBINIZE_OPTS += -p $(BR2_TARGET_ROOTFS_UBI_PEBSIZE)
+ifneq ($(BR2_TARGET_ROOTFS_UBI_SUBSIZE),0)
+UBI_UBINIZE_OPTS += -s $(BR2_TARGET_ROOTFS_UBI_SUBSIZE)
+endif
+
+ROOTFS_UBI_DEPENDENCIES = rootfs-ubifs
+
+define ROOTFS_UBI_CMD
+	cp fs/ubifs/ubinize.cfg . ;\
+	echo "image=$$@fs" \
+		>> ./ubinize.cfg ;\
+	$(HOST_DIR)/usr/sbin/ubinize -o $$@ $(UBI_UBINIZE_OPTS) ubinize.cfg ;\
+	rm ubinize.cfg
+endef
+
+$(eval $(call ROOTFS_TARGET,ubi))

fs/ubifs/ubinize.cfg

@@ -0,0 +1,7 @@
+[ubifs]
+mode=ubi
+vol_id=0
+vol_type=dynamic
+vol_name=rootfs
+vol_alignment=1
+vol_flags=autoresize