UBI: incorporate maximum write size

Incorporate MTD write buffer size into UBI device information
because UBIFS needs this field. UBI does not use it ATM, just
provides to upper layers in 'struct ubi_device_info'.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

3 files changed, 18 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 5ebe280225d6..f38e8de81811 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -690,11 +690,25 @@ static int io_init(struct ubi_device *ubi)
         ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
         ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
 
+        ubi->max_write_size = ubi->mtd->writebufsize;
+        /*
+         * Maximum write size has to be greater or equivalent to min. I/O
+         * size, and be multiple of min. I/O size.
+         */
+        if (ubi->max_write_size < ubi->min_io_size ||
+            ubi->max_write_size % ubi->min_io_size ||
+            !is_power_of_2(ubi->max_write_size)) {
+                ubi_err("bad write buffer size %d for %d min. I/O unit",
+                        ubi->max_write_size, ubi->min_io_size);
+                return -EINVAL;
+        }
+
         /* Calculate default aligned sizes of EC and VID headers */
         ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
         ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
 
         dbg_msg("min_io_size      %d", ubi->min_io_size);
+        dbg_msg("max_write_size   %d", ubi->max_write_size);
         dbg_msg("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
         dbg_msg("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
         dbg_msg("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 69fa4ef03c53..701df4f848f6 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -41,6 +41,7 @@ void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
         di->ubi_num = ubi->ubi_num;
         di->leb_size = ubi->leb_size;
         di->min_io_size = ubi->min_io_size;
+        di->max_write_size = ubi->max_write_size;
         di->ro_mode = ubi->ro_mode;
         di->cdev = ubi->cdev.dev;
 }
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 0b0149c41fe3..b78994330ebc 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -381,6 +381,8 @@ struct ubi_wl_entry;
  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
  *               not
  * @nor_flash: non-zero if working on top of NOR flash
+ * @max_write_size: maximum amount of bytes the underlying flash can write at a
+ *                  time (MTD write buffer size)
  * @mtd: MTD device descriptor
  *
  * @peb_buf1: a buffer of PEB size used for different purposes
@@ -464,6 +466,7 @@ struct ubi_device {
         int vid_hdr_shift;
         unsigned int bad_allowed:1;
         unsigned int nor_flash:1;
+        int max_write_size;
         struct mtd_info *mtd;
 
         void *peb_buf1;