[PATCH 03/14] ubi: fastmap: Add support for flags

[Richard Weinberger <richard@nod.at>]

With version 2 of fastmap, flags are supported.
We fall back to scanning mode if unsupported flags are found.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 drivers/mtd/ubi/fastmap.c   | 24 ++++++++++++++++++++----
 drivers/mtd/ubi/ubi-media.h | 11 +++++++++--
 drivers/mtd/ubi/ubi.h       |  2 ++
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 768fa8a76867..1ebb5d15ab1a 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -949,9 +949,24 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
 		goto free_fm_sb;
 	}
 
-	if (fmsb->version != UBI_FM_FMT_VERSION) {
-		ubi_err(ubi, "bad fastmap version: %i, expected: %i",
-			fmsb->version, UBI_FM_FMT_VERSION);
+	fm->flags = be32_to_cpu(fmsb->flags);
+
+	if (fmsb->version == 1) {
+		if (fm->flags != 0) {
+			ubi_err(ubi, "fastmap flags are non-zero: %#x",
+				fm->flags);
+			ret = UBI_BAD_FASTMAP;
+			goto free_fm_sb;
+		}
+	} else if (fmsb->version == 2) {
+		if ((fm->flags & UBI_FM_SB_FLG_MASK) != UBI_FM_SB_FLG_MASK) {
+			ubi_err(ubi, "unsupported fastmap flags present: %#x",
+				fm->flags);
+			ret = UBI_BAD_FASTMAP;
+			goto free_fm_sb;
+		}
+	} else {
+		ubi_err(ubi, "bad fastmap version: %i", fmsb->version);
 		ret = UBI_BAD_FASTMAP;
 		goto free_fm_sb;
 	}
@@ -1229,10 +1244,11 @@ static int ubi_write_fastmap(struct ubi_device *ubi,
 	ubi_assert(fm_pos <= ubi->fm_size);
 
 	fmsb->magic = cpu_to_be32(UBI_FM_SB_MAGIC);
-	fmsb->version = UBI_FM_FMT_VERSION;
+	fmsb->version = UBI_FM_FMT_WRITE_VERSION;
 	fmsb->used_blocks = cpu_to_be32(new_fm->used_blocks);
 	/* the max sqnum will be filled in while *reading* the fastmap */
 	fmsb->sqnum = 0;
+	fmsb->flags = 0;
 
 	fmh->magic = cpu_to_be32(UBI_FM_HDR_MAGIC);
 	free_peb_count = 0;
diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
index 195ff8ca8211..6136a97f4844 100644
--- a/drivers/mtd/ubi/ubi-media.h
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -365,7 +365,10 @@ struct ubi_vtbl_record {
 #define UBI_FM_DATA_VOLUME_ID	(UBI_LAYOUT_VOLUME_ID + 2)
 
 /* fastmap on-flash data structure format version */
-#define UBI_FM_FMT_VERSION	1
+#define UBI_FM_FMT_VERSION		2
+
+/* this implementation writes always version 1 */
+#define UBI_FM_FMT_WRITE_VERSION	1
 
 #define UBI_FM_SB_MAGIC		0x7B11D69F
 #define UBI_FM_HDR_MAGIC	0xD4B82EF7
@@ -387,6 +390,8 @@ struct ubi_vtbl_record {
 #define UBI_FM_MIN_POOL_SIZE	8
 #define UBI_FM_MAX_POOL_SIZE	256
 
+#define UBI_FM_SB_FLG_MASK	0
+
 /**
  * struct ubi_fm_sb - UBI fastmap super block
  * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC)
@@ -396,6 +401,7 @@ struct ubi_vtbl_record {
  * @block_loc: an array containing the location of all PEBs of the fastmap
  * @block_ec: the erase counter of each used PEB
  * @sqnum: highest sequence number value at the time while taking the fastmap
+ * @flags: fastmap specific flags, only used with @version > 1, zero otherwise
  *
  */
 struct ubi_fm_sb {
@@ -407,7 +413,8 @@ struct ubi_fm_sb {
 	__be32 block_loc[UBI_FM_MAX_BLOCKS];
 	__be32 block_ec[UBI_FM_MAX_BLOCKS];
 	__be64 sqnum;
-	__u8 padding2[32];
+	__be32 flags;
+	__u8 padding2[28];
 } __packed;
 
 /**
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index f5ba97c46160..4fab3790733b 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -249,6 +249,7 @@ struct ubi_volume_desc;
  * @used_blocks: number of used PEBs
  * @max_pool_size: maximal size of the user pool
  * @max_wl_pool_size: maximal size of the pool used by the WL sub-system
+ * @flags: fastmap flags
  */
 struct ubi_fastmap_layout {
 	struct ubi_wl_entry *e[UBI_FM_MAX_BLOCKS];
@@ -256,6 +257,7 @@ struct ubi_fastmap_layout {
 	int used_blocks;
 	int max_pool_size;
 	int max_wl_pool_size;
+	int flags;
 };
 
 /**
-- 
2.13.6