2 files changed, 91 insertions, 7 deletions

diff --git a/include/mtd/ubi-header.h b/include/mtd/ubi-header.h
index 74efa7763479..292f916ea564 100644
--- a/include/mtd/ubi-header.h
+++ b/include/mtd/ubi-header.h
@@ -58,6 +58,43 @@ enum {
 };
 
 /*
+ * Volume flags used in the volume table record.
+ *
+ * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume
+ *
+ * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume
+ * table. UBI automatically re-sizes the volume which has this flag and makes
+ * the volume to be of largest possible size. This means that if after the
+ * initialization UBI finds out that there are available physical eraseblocks
+ * present on the device, it automatically appends all of them to the volume
+ * (the physical eraseblocks reserved for bad eraseblocks handling and other
+ * reserved physical eraseblocks are not taken). So, if there is a volume with
+ * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical
+ * eraseblocks will be zero after UBI is loaded, because all of them will be
+ * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared
+ * after the volume had been initialized.
+ *
+ * The auto-resize feature is useful for device production purposes. For
+ * example, different NAND flash chips may have different amount of initial bad
+ * eraseblocks, depending of particular chip instance. Manufacturers of NAND
+ * chips usually guarantee that the amount of initial bad eraseblocks does not
+ * exceed certain percent, e.g. 2%. When one creates an UBI image which will be
+ * flashed to the end devices in production, he does not know the exact amount
+ * of good physical eraseblocks the NAND chip on the device will have, but this
+ * number is required to calculate the volume sized and put them to the volume
+ * table of the UBI image. In this case, one of the volumes (e.g., the one
+ * which will store the root file system) is marked as "auto-resizable", and
+ * UBI will adjust its size on the first boot if needed.
+ *
+ * Note, first UBI reserves some amount of physical eraseblocks for bad
+ * eraseblock handling, and then re-sizes the volume, not vice-versa. This
+ * means that the pool of reserved physical eraseblocks will always be present.
+ */
+enum {
+        UBI_VTBL_AUTORESIZE_FLG = 0x01,
+};
+
+/*
  * Compatibility constants used by internal volumes.
  *
  * @UBI_COMPAT_DELETE: delete this internal volume before anything is written
@@ -262,7 +299,9 @@ struct ubi_vid_hdr {
 
 /* The layout volume contains the volume table */
 
-#define UBI_LAYOUT_VOL_ID        UBI_INTERNAL_VOL_START
+#define UBI_LAYOUT_VOLUME_ID     UBI_INTERNAL_VOL_START
+#define UBI_LAYOUT_VOLUME_TYPE   UBI_VID_DYNAMIC
+#define UBI_LAYOUT_VOLUME_ALIGN  1
 #define UBI_LAYOUT_VOLUME_EBS    2
 #define UBI_LAYOUT_VOLUME_NAME   "layout volume"
 #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT
@@ -289,7 +328,8 @@ struct ubi_vid_hdr {
  * @upd_marker: if volume update was started but not finished
  * @name_len: volume name length
  * @name: the volume name
- * @padding2: reserved, zeroes
+ * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG)
+ * @padding: reserved, zeroes
  * @crc: a CRC32 checksum of the record
  *
  * The volume table records are stored in the volume table, which is stored in
@@ -324,7 +364,8 @@ struct ubi_vtbl_record {
         __u8    upd_marker;
         __be16  name_len;
         __u8    name[UBI_VOL_NAME_MAX+1];
-        __u8    padding2[24];
+        __u8    flags;
+        __u8    padding[23];
         __be32  crc;
 } __attribute__ ((packed));
 
diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h
index 4d184a7f80a8..a7421f130cc0 100644
--- a/include/mtd/ubi-user.h
+++ b/include/mtd/ubi-user.h
@@ -63,7 +63,7 @@
  *
  * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
  * corresponding UBI volume character device. A pointer to a 64-bit update
- * size should be passed to the IOCTL. After then, UBI expects user to write
+ * size should be passed to the IOCTL. After this, UBI expects user to write
  * this number of bytes to the volume character device. The update is finished
  * when the claimed number of bytes is passed. So, the volume update sequence
  * is something like:
@@ -72,6 +72,15 @@
  * ioctl(fd, UBI_IOCVOLUP, &image_size);
  * write(fd, buf, image_size);
  * close(fd);
+ *
+ * Atomic eraseblock change
+ * ~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL
+ * command of the corresponding UBI volume character device. A pointer to
+ * &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is
+ * expected to write the requested amount of bytes. This is similar to the
+ * "volume update" IOCTL.
  */
 
 /*
@@ -113,11 +122,30 @@
 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
 /* An eraseblock erasure command, used for debugging, disabled by default */
 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
+/* An atomic eraseblock change command */
+#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)
 
 /* Maximum MTD device name length supported by UBI */
 #define MAX_UBI_MTD_NAME_LEN 127
 
 /*
+ * UBI data type hint constants.
+ *
+ * UBI_LONGTERM: long-term data
+ * UBI_SHORTTERM: short-term data
+ * UBI_UNKNOWN: data persistence is unknown
+ *
+ * These constants are used when data is written to UBI volumes in order to
+ * help the UBI wear-leveling unit to find more appropriate physical
+ * eraseblocks.
+ */
+enum {
+        UBI_LONGTERM  = 1,
+        UBI_SHORTTERM = 2,
+        UBI_UNKNOWN   = 3,
+};
+
+/*
  * UBI volume type constants.
  *
  * @UBI_DYNAMIC_VOLUME: dynamic volume
@@ -125,7 +153,7 @@
  */
 enum {
         UBI_DYNAMIC_VOLUME = 3,
-        UBI_STATIC_VOLUME = 4,
+        UBI_STATIC_VOLUME  = 4,
 };
 
 /**
@@ -137,7 +165,7 @@ enum {
  *
  * This data structure is used to specify MTD device UBI has to attach and the
  * parameters it has to use. The number which should be assigned to the new UBI
- * device is passed in @ubi_num. UBI may automatically assing the number if
+ * device is passed in @ubi_num. UBI may automatically assign the number if
  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
  * @ubi_num.
  *
@@ -176,7 +204,7 @@ struct ubi_attach_req {
  * @padding2: reserved for future, not used, has to be zeroed
  * @name: volume name
  *
- * This structure is used by userspace programs when creating new volumes. The
+ * This structure is used by user-space programs when creating new volumes. The
  * @used_bytes field is only necessary when creating static volumes.
  *
  * The @alignment field specifies the required alignment of the volume logical
@@ -222,4 +250,19 @@ struct ubi_rsvol_req {
         int32_t vol_id;
 } __attribute__ ((packed));
 
+/**
+ * struct ubi_leb_change_req - a data structure used in atomic logical
+ *                             eraseblock change requests.
+ * @lnum: logical eraseblock number to change
+ * @bytes: how many bytes will be written to the logical eraseblock
+ * @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
+ * @padding: reserved for future, not used, has to be zeroed
+ */
+struct ubi_leb_change_req {
+        int32_t lnum;
+        int32_t bytes;
+        uint8_t dtype;
+        uint8_t padding[7];
+} __attribute__ ((packed));
+
 #endif /* __UBI_USER_H__ */