From: Gabor Juhos <juhosg@openwrt.org>
Subject: kernel/3.10: add separate rootfs partition parser

lede-commit: daec7ad7688415156e2730e401503d09bd3acf91
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
---
 drivers/mtd/mtdpart.c          | 29 +++++++++++++++++++++++++++++
 include/linux/mtd/mtd.h        | 18 ++++++++++++++++++
 include/linux/mtd/partitions.h |  2 ++
 3 files changed, 49 insertions(+)

--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -800,6 +800,17 @@ run_parsers_by_type(struct mtd_part *sla
 	return nr_parts;
 }
 
+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;
+}
+
 #ifdef CONFIG_MTD_SPLIT_FIRMWARE_NAME
 #define SPLIT_FIRMWARE_NAME	CONFIG_MTD_SPLIT_FIRMWARE_NAME
 #else
@@ -1203,6 +1214,24 @@ int mtd_is_partition(const struct mtd_in
 }
 EXPORT_SYMBOL_GPL(mtd_is_partition);
 
+struct mtd_info *mtdpart_get_master(const struct mtd_info *mtd)
+{
+	if (!mtd_is_partition(mtd))
+		return (struct mtd_info *)mtd;
+
+	return mtd_to_part(mtd)->parent;
+}
+EXPORT_SYMBOL_GPL(mtdpart_get_master);
+
+uint64_t mtdpart_get_offset(const struct mtd_info *mtd)
+{
+	if (!mtd_is_partition(mtd))
+		return 0;
+
+	return mtd_to_part(mtd)->offset;
+}
+EXPORT_SYMBOL_GPL(mtdpart_get_offset);
+
 /* Returns the size of the entire flash chip */
 uint64_t mtd_get_device_size(const struct mtd_info *mtd)
 {
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -493,6 +493,24 @@ static inline uint32_t mtd_mod_by_eb(uin
 	return do_div(sz, mtd->erasesize);
 }
 
+static inline uint64_t mtd_roundup_to_eb(uint64_t sz, struct mtd_info *mtd)
+{
+	if (mtd_mod_by_eb(sz, mtd) == 0)
+		return sz;
+
+	/* Round up to next erase block */
+	return (mtd_div_by_eb(sz, mtd) + 1) * mtd->erasesize;
+}
+
+static inline uint64_t mtd_rounddown_to_eb(uint64_t sz, struct mtd_info *mtd)
+{
+	if (mtd_mod_by_eb(sz, mtd) == 0)
+		return sz;
+
+	/* Round down to the start of the current erase block */
+	return (mtd_div_by_eb(sz, mtd)) * mtd->erasesize;
+}
+
 static inline uint32_t mtd_div_by_ws(uint64_t sz, struct mtd_info *mtd)
 {
 	if (mtd->writesize_shift)
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -115,6 +115,8 @@ int mtd_is_partition(const struct mtd_in
 int mtd_add_partition(struct mtd_info *master, const char *name,
 		      long long offset, long long length);
 int mtd_del_partition(struct mtd_info *master, int partno);
+struct mtd_info *mtdpart_get_master(const struct mtd_info *mtd);
+uint64_t mtdpart_get_offset(const struct mtd_info *mtd);
 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);