From 2a295753a10823a47542c779a25bbb1f52c71281 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Fri, 3 Aug 2012 10:27:13 +0200
Subject: [PATCH 19/25] owrt mtd split

---
 .../mips/include/asm/mach-lantiq/xway/lantiq_soc.h |    1 +
 arch/mips/lantiq/setup.c                           |    7 +
 drivers/mtd/Kconfig                                |    4 +
 drivers/mtd/mtdpart.c                              |  173 +++++++++++++++++++-
 4 files changed, 184 insertions(+), 1 deletions(-)

Index: linux-3.9-rc4/drivers/mtd/Kconfig
===================================================================
--- linux-3.9-rc4.orig/drivers/mtd/Kconfig	2013-03-27 09:26:32.005789709 +0100
+++ linux-3.9-rc4/drivers/mtd/Kconfig	2013-03-27 09:26:35.669789796 +0100
@@ -31,6 +31,10 @@
 	bool "Automatically split 'rootfs' partition for squashfs"
 	default y
 
+config MTD_UIMAGE_SPLIT
+	bool "Automatically split 'linux' partition into 'kernel' and 'rootfs'"
+	default y
+
 config MTD_REDBOOT_PARTS
 	tristate "RedBoot partition table parsing"
 	---help---
Index: linux-3.9-rc4/drivers/mtd/mtdpart.c
===================================================================
--- linux-3.9-rc4.orig/drivers/mtd/mtdpart.c	2013-03-27 09:26:32.281789715 +0100
+++ linux-3.9-rc4/drivers/mtd/mtdpart.c	2013-03-27 17:20:12.874466937 +0100
@@ -844,6 +844,99 @@
 }
 #endif /* CONFIG_MTD_ROOTFS_SPLIT */
 
+#ifdef CONFIG_MTD_UIMAGE_SPLIT
+static unsigned long find_uimage_size(struct mtd_info *mtd,
+				      unsigned long offset)
+{
+#define UBOOT_MAGIC	0x56190527
+	unsigned long magic = 0;
+	unsigned long temp;
+	size_t len;
+	int ret;
+
+	ret = mtd_read(mtd, offset, 4, &len, (void *)&magic);
+	if (ret || len != sizeof(magic))
+		return 0;
+
+	if (le32_to_cpu(magic) != UBOOT_MAGIC)
+		return 0;
+
+	ret = mtd_read(mtd, offset + 12, 4, &len, (void *)&temp);
+	if (ret || len != sizeof(temp))
+		return 0;
+
+	return be32_to_cpu(temp) + 0x40;
+}
+
+static int detect_squashfs_partition(struct mtd_info *mtd, unsigned long offset)
+{
+	unsigned long temp;
+	size_t len;
+	int ret;
+
+	ret = mtd_read(mtd, offset, 4, &len, (void *)&temp);
+	if (ret || len != sizeof(temp))
+		return 0;
+
+	return le32_to_cpu(temp) == SQUASHFS_MAGIC;
+}
+
+static unsigned long find_squashfs_offset(struct mtd_info *mtd, unsigned long _offset)
+{
+	/* scan the first 2MB at 64K offsets */
+	int i;
+
+	for (i = 0; i < 32; i++) {
+		unsigned long offset = i * 64 * 1024;
+		if (detect_squashfs_partition(mtd, _offset + offset))
+			return offset;
+	}
+	return 0;
+}
+
+static int split_uimage(struct mtd_info *mtd,
+			const struct mtd_partition *part)
+{
+	static struct mtd_partition split_partitions[] = {
+		{
+			.name = "kernel",
+			.offset = 0x0,
+			.size = 0x0,
+		}, {
+			.name = "rootfs",
+			.offset = 0x0,
+			.size = 0x0,
+		},
+	};
+
+	split_partitions[0].size = find_uimage_size(mtd, part->offset);
+	if (!split_partitions[0].size) {
+		split_partitions[0].size = find_squashfs_offset(mtd, part->offset);
+		if (!split_partitions[0].size) {
+			pr_err("failed to split firmware partition\n");
+			return -1;
+		}
+	}
+
+	if (!detect_squashfs_partition(mtd,
+				       part->offset
+				       + split_partitions[0].size)) {
+		split_partitions[0].size &= ~(mtd->erasesize - 1);
+		split_partitions[0].size += mtd->erasesize;
+	} else {
+		pr_info("found squashfs behind kernel\n");
+	}
+
+	split_partitions[0].offset = part->offset;
+	split_partitions[1].offset = part->offset + split_partitions[0].size;
+	split_partitions[1].size = part->size - split_partitions[0].size;
+
+	add_mtd_partitions(mtd, split_partitions, 2);
+
+	return 0;
+}
+#endif
+
 /*
  * 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
@@ -860,7 +953,7 @@
 	struct mtd_part *slave;
 	uint64_t cur_offset = 0;
 	int i;
-#ifdef CONFIG_MTD_ROOTFS_SPLIT
+#if defined(CONFIG_MTD_ROOTFS_SPLIT) || defined(CONFIG_MTD_UIMAGE_SPLIT)
 	int ret;
 #endif
 
@@ -877,6 +970,14 @@
 
 		add_mtd_device(&slave->mtd);
 
+#ifdef CONFIG_MTD_UIMAGE_SPLIT
+		if (!strcmp(parts[i].name, "firmware")) {
+			ret = split_uimage(master, &parts[i]);
+			if (ret)
+				printk(KERN_WARNING "Can't split firmware partition\n");
+		}
+#endif
+
 		if (!strcmp(parts[i].name, "rootfs")) {
 #ifdef CONFIG_MTD_ROOTFS_ROOT_DEV
 			if (ROOT_DEV == 0) {