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-rw-r--r--drivers/mtd/ubi/build.c5
-rw-r--r--drivers/mtd/ubi/io.c58
-rw-r--r--drivers/mtd/ubi/ubi.h4
3 files changed, 64 insertions, 3 deletions
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index db0b9cb64c6..e1f7d0a78b9 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -657,6 +657,11 @@ static int io_init(struct ubi_device *ubi)
if (ubi->mtd->block_isbad && ubi->mtd->block_markbad)
ubi->bad_allowed = 1;
+ if (ubi->mtd->type == MTD_NORFLASH) {
+ ubi_assert(ubi->mtd->writesize == 1);
+ ubi->nor_flash = 1;
+ }
+
ubi->min_io_size = ubi->mtd->writesize;
ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 1ea14218de0..c3bd2e34c64 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -266,8 +266,8 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
addr = (loff_t)pnum * ubi->peb_size + offset;
err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
if (err) {
- ubi_err("error %d while writing %d bytes to PEB %d:%d, written"
- " %zd bytes", err, len, pnum, offset, written);
+ ubi_err("error %d while writing %d bytes to PEB %d:%d, written "
+ "%zd bytes", err, len, pnum, offset, written);
ubi_dbg_dump_stack();
} else
ubi_assert(written == len);
@@ -454,6 +454,54 @@ out:
}
/**
+ * nor_erase_prepare - prepare a NOR flash PEB for erasure.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock number to prepare
+ *
+ * NOR flash, or at least some of them, have peculiar embedded PEB erasure
+ * algorithm: the PEB is first filled with zeroes, then it is erased. And
+ * filling with zeroes starts from the end of the PEB. This was observed with
+ * Spansion S29GL512N NOR flash.
+ *
+ * This means that in case of a power cut we may end up with intact data at the
+ * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
+ * EC and VID headers are OK, but a large chunk of data at the end of PEB is
+ * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
+ * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
+ *
+ * This function is called before erasing NOR PEBs and it zeroes out EC and VID
+ * magic numbers in order to invalidate them and prevent the failures. Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
+{
+ int err;
+ size_t written;
+ loff_t addr;
+ uint32_t data = 0;
+
+ addr = (loff_t)pnum * ubi->peb_size;
+ err = ubi->mtd->write(ubi->mtd, addr, 4, &written, &data);
+ if (err) {
+ ubi_err("error %d while writing 4 bytes to PEB %d:0, written "
+ "%zd bytes", err, pnum, 0, written);
+ ubi_dbg_dump_stack();
+ return err;
+ }
+
+ addr += ubi->vid_hdr_aloffset;
+ err = ubi->mtd->write(ubi->mtd, addr, 4, &written, &data);
+ if (err) {
+ ubi_err("error %d while writing 4 bytes to PEB %d:%d, written "
+ "%zd bytes", err, pnum, ubi->vid_hdr_aloffset, written);
+ ubi_dbg_dump_stack();
+ return err;
+ }
+
+ return 0;
+}
+
+/**
* ubi_io_sync_erase - synchronously erase a physical eraseblock.
* @ubi: UBI device description object
* @pnum: physical eraseblock number to erase
@@ -484,6 +532,12 @@ int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
return -EROFS;
}
+ if (ubi->nor_flash) {
+ err = nor_erase_prepare(ubi, pnum);
+ if (err)
+ return err;
+ }
+
if (torture) {
ret = torture_peb(ubi, pnum);
if (ret < 0)
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 64604e8809e..6a5fe963378 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -373,6 +373,7 @@ struct ubi_wl_entry;
* @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
* @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
* not
+ * @nor_flash: non-zero if working on top of NOR flash
* @mtd: MTD device descriptor
*
* @peb_buf1: a buffer of PEB size used for different purposes
@@ -454,7 +455,8 @@ struct ubi_device {
int vid_hdr_offset;
int vid_hdr_aloffset;
int vid_hdr_shift;
- int bad_allowed;
+ unsigned int bad_allowed:1;
+ unsigned int nor_flash:1;
struct mtd_info *mtd;
void *peb_buf1;