openwrt/target/linux/generic/patches-3.10/400-mtd-add-rootfs-split-support.patch

--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -12,6 +12,27 @@ menuconfig MTD
 
 if MTD
 
+menu "OpenWrt specific MTD options"
+
+config MTD_ROOTFS_ROOT_DEV
+	bool "Automatically set 'rootfs' partition to be root filesystem"
+	default y
+
+config MTD_ROOTFS_SPLIT
+	bool "Automatically split 'rootfs' partition for squashfs"
+	default y
+
+config MTD_UIMAGE_SPLIT
+	bool "Automatically split off rootfs from a kernel partition containing a uImage"
+	default y
+
+config MTD_UIMAGE_SPLIT_NAME
+	string "uImage partition name"
+	depends on MTD_UIMAGE_SPLIT
+	default "firmware"
+
+endmenu
+
 config MTD_TESTS
 	tristate "MTD tests support (DANGEROUS)"
 	depends on m
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -29,6 +29,8 @@
 #include <linux/kmod.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
+#include <linux/root_dev.h>
+#include <linux/magic.h>
 #include <linux/err.h>
 
 #include "mtdcore.h"
@@ -45,13 +47,14 @@ struct mtd_part {
 	struct list_head list;
 };
 
+static void mtd_partition_split(struct mtd_info *master, struct mtd_part *part);
+
 /*
  * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
  * the pointer to that structure with this macro.
  */
 #define PART(x)  ((struct mtd_part *)(x))
 
-
 /*
  * MTD methods which simply translate the effective address and pass through
  * to the _real_ device.
@@ -533,8 +536,10 @@ out_register:
 	return slave;
 }
 
-int mtd_add_partition(struct mtd_info *master, char *name,
-		      long long offset, long long length)
+
+static int
+__mtd_add_partition(struct mtd_info *master, char *name,
+		    long long offset, long long length, bool dup_check)
 {
 	struct mtd_partition part;
 	struct mtd_part *p, *new;
@@ -566,21 +571,24 @@ int mtd_add_partition(struct mtd_info *m
 	end = offset + length;
 
 	mutex_lock(&mtd_partitions_mutex);
-	list_for_each_entry(p, &mtd_partitions, list)
-		if (p->master == master) {
-			if ((start >= p->offset) &&
-			    (start < (p->offset + p->mtd.size)))
-				goto err_inv;
-
-			if ((end >= p->offset) &&
-			    (end < (p->offset + p->mtd.size)))
-				goto err_inv;
-		}
+	if (dup_check) {
+		list_for_each_entry(p, &mtd_partitions, list)
+			if (p->master == master) {
+				if ((start >= p->offset) &&
+				    (start < (p->offset + p->mtd.size)))
+					goto err_inv;
+
+				if ((end >= p->offset) &&
+				    (end < (p->offset + p->mtd.size)))
+					goto err_inv;
+			}
+	}
 
 	list_add(&new->list, &mtd_partitions);
 	mutex_unlock(&mtd_partitions_mutex);
 
 	add_mtd_device(&new->mtd);
+	mtd_partition_split(master, new);
 
 	return ret;
 err_inv:
@@ -590,6 +598,12 @@ err_inv:
 }
 EXPORT_SYMBOL_GPL(mtd_add_partition);
 
+int mtd_add_partition(struct mtd_info *master, char *name,
+		      long long offset, long long length)
+{
+	return __mtd_add_partition(master, name, offset, length, true);
+}
+
 int mtd_del_partition(struct mtd_info *master, int partno)
 {
 	struct mtd_part *slave, *next;
@@ -613,6 +627,148 @@ int mtd_del_partition(struct mtd_info *m
 }
 EXPORT_SYMBOL_GPL(mtd_del_partition);
 
+static inline unsigned long
+mtd_pad_erasesize(struct mtd_info *mtd, int offset, int len)
+{
+	unsigned long mask = mtd->erasesize - 1;
+
+	len += offset & mask;
+	len = (len + mask) & ~mask;
+	len -= offset & mask;
+	return len;
+}
+
+#define ROOTFS_SPLIT_NAME "rootfs_data"
+
+struct squashfs_super_block {
+	__le32 s_magic;
+	__le32 pad0[9];
+	__le64 bytes_used;
+};
+
+
+static int split_squashfs(struct mtd_info *master, int offset, int *split_offset)
+{
+	struct squashfs_super_block sb;
+	int len, ret;
+
+	ret = mtd_read(master, offset, sizeof(sb), &len, (void *) &sb);
+	if (ret || (len != sizeof(sb))) {
+		printk(KERN_ALERT "split_squashfs: error occured while reading "
+			"from \"%s\"\n", master->name);
+		return -EINVAL;
+	}
+
+	if (SQUASHFS_MAGIC != le32_to_cpu(sb.s_magic) ) {
+		printk(KERN_ALERT "split_squashfs: no squashfs found in \"%s\"\n",
+			master->name);
+		*split_offset = 0;
+		return 0;
+	}
+
+	if (le64_to_cpu((sb.bytes_used)) <= 0) {
+		printk(KERN_ALERT "split_squashfs: squashfs is empty in \"%s\"\n",
+			master->name);
+		*split_offset = 0;
+		return 0;
+	}
+
+	len = (u32) le64_to_cpu(sb.bytes_used);
+	len = mtd_pad_erasesize(master, offset, len);
+	*split_offset = offset + len;
+
+	return 0;
+}
+
+static void split_rootfs_data(struct mtd_info *master, struct mtd_part *part)
+{
+	unsigned int split_offset = 0;
+	unsigned int split_size;
+	int ret;
+
+	ret = split_squashfs(master, part->offset, &split_offset);
+	if (ret)
+		return;
+
+	if (split_offset <= 0)
+		return;
+
+	split_size = part->mtd.size - (split_offset - part->offset);
+	printk(KERN_INFO "mtd: partition \"%s\" created automatically, ofs=0x%x, len=0x%x\n",
+		ROOTFS_SPLIT_NAME, split_offset, split_size);
+
+	__mtd_add_partition(master, ROOTFS_SPLIT_NAME, split_offset,
+			    split_size, false);
+}
+
+#define UBOOT_MAGIC	0x27051956
+
+#ifdef CONFIG_MTD_UIMAGE_SPLIT_NAME
+#define UIMAGE_SPLIT_NAME	CONFIG_MTD_UIMAGE_SPLIT_NAME
+#else
+#define UIMAGE_SPLIT_NAME	"unused"
+#endif
+
+static void split_uimage(struct mtd_info *master, struct mtd_part *part)
+{
+	struct {
+		__be32 magic;
+		__be32 pad[2];
+		__be32 size;
+	} hdr;
+	size_t len;
+
+	if (strcmp(part->mtd.name, UIMAGE_SPLIT_NAME) != 0)
+		return;
+
+	if (mtd_read(master, part->offset, sizeof(hdr), &len, (void *) &hdr))
+		return;
+
+	if (len != sizeof(hdr) || hdr.magic != cpu_to_be32(UBOOT_MAGIC))
+		return;
+
+	len = be32_to_cpu(hdr.size) + 0x40;
+	len = mtd_pad_erasesize(master, part->offset, len);
+	if (len + master->erasesize > part->mtd.size)
+		return;
+
+	__mtd_add_partition(master, "rootfs", part->offset + len,
+			    part->mtd.size - len, false);
+}
+
+void __weak arch_split_mtd_part(struct mtd_info *master, const char *name,
+                                int offset, int size)
+{
+}
+
+
+static void mtd_partition_split(struct mtd_info *master, struct mtd_part *part)
+{
+	static int rootfs_found = 0;
+
+	if (rootfs_found)
+		return;
+
+	if (!strcmp(part->mtd.name, "rootfs")) {
+		rootfs_found = 1;
+
+		if (config_enabled(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
+		    ROOT_DEV == 0) {
+			printk(KERN_NOTICE "mtd: partition \"rootfs\" "
+				"set to be root filesystem\n");
+			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, part->mtd.index);
+		}
+
+		if (config_enabled(CONFIG_MTD_ROOTFS_SPLIT))
+			split_rootfs_data(master, part);
+	}
+
+	if (config_enabled(CONFIG_MTD_UIMAGE_SPLIT))
+		split_uimage(master, part);
+
+	arch_split_mtd_part(master, part->mtd.name, part->offset,
+			    part->mtd.size);
+}
 /*
  * This function, given a master MTD object and a partition table, creates
  * and registers slave MTD objects which are bound to the master according to
@@ -642,6 +798,7 @@ int add_mtd_partitions(struct mtd_info *
 		mutex_unlock(&mtd_partitions_mutex);
 
 		add_mtd_device(&slave->mtd);
+		mtd_partition_split(master, slave);
 
 		cur_offset = slave->offset + slave->mtd.size;
 	}
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -84,5 +84,7 @@ int mtd_add_partition(struct mtd_info *m
 		      long long offset, long long length);
 int mtd_del_partition(struct mtd_info *master, int partno);
 uint64_t mtd_get_device_size(const struct mtd_info *mtd);
+extern void __weak arch_split_mtd_part(struct mtd_info *master,
+				       const char *name, int offset, int size);
 
 #endif