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path: root/drivers/mtd/ubi/io.c
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Diffstat (limited to 'drivers/mtd/ubi/io.c')
-rw-r--r--drivers/mtd/ubi/io.c157
1 files changed, 61 insertions, 96 deletions
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index effaff28bab1..4cb69925d8d9 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -98,17 +98,12 @@ static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
const struct ubi_vid_hdr *vid_hdr);
-static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
- int len);
-static int paranoid_check_empty(struct ubi_device *ubi, int pnum);
#else
#define paranoid_check_not_bad(ubi, pnum) 0
#define paranoid_check_peb_ec_hdr(ubi, pnum) 0
#define paranoid_check_ec_hdr(ubi, pnum, ec_hdr) 0
#define paranoid_check_peb_vid_hdr(ubi, pnum) 0
#define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
-#define paranoid_check_all_ff(ubi, pnum, offset, len) 0
-#define paranoid_check_empty(ubi, pnum) 0
#endif
/**
@@ -244,7 +239,7 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
return err > 0 ? -EINVAL : err;
/* The area we are writing to has to contain all 0xFF bytes */
- err = paranoid_check_all_ff(ubi, pnum, offset, len);
+ err = ubi_dbg_check_all_ff(ubi, pnum, offset, len);
if (err)
return err > 0 ? -EINVAL : err;
@@ -271,8 +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);
@@ -350,7 +345,7 @@ retry:
return -EIO;
}
- err = paranoid_check_all_ff(ubi, pnum, 0, ubi->peb_size);
+ err = ubi_dbg_check_all_ff(ubi, pnum, 0, ubi->peb_size);
if (err)
return err > 0 ? -EINVAL : err;
@@ -459,6 +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, (void *)&data);
+ if (err) {
+ ubi_err("error %d while writing 4 bytes to PEB %d:%d, 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, (void *)&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
@@ -489,6 +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)
@@ -672,11 +721,6 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
if (read_err != -EBADMSG &&
check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
/* The physical eraseblock is supposedly empty */
- err = paranoid_check_all_ff(ubi, pnum, 0,
- ubi->peb_size);
- if (err)
- return err > 0 ? UBI_IO_BAD_EC_HDR : err;
-
if (verbose)
ubi_warn("no EC header found at PEB %d, "
"only 0xFF bytes", pnum);
@@ -752,6 +796,7 @@ int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
ec_hdr->version = UBI_VERSION;
ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
+ ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
ec_hdr->hdr_crc = cpu_to_be32(crc);
@@ -947,15 +992,6 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
if (read_err != -EBADMSG &&
check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
/* The physical eraseblock is supposedly free */
-
- /*
- * The below is just a paranoid check, it has to be
- * compiled out if paranoid checks are disabled.
- */
- err = paranoid_check_empty(ubi, pnum);
- if (err)
- return err > 0 ? UBI_IO_BAD_VID_HDR : err;
-
if (verbose)
ubi_warn("no VID header found at PEB %d, "
"only 0xFF bytes", pnum);
@@ -1229,7 +1265,7 @@ exit:
}
/**
- * paranoid_check_all_ff - check that a region of flash is empty.
+ * ubi_dbg_check_all_ff - check that a region of flash is empty.
* @ubi: UBI device description object
* @pnum: the physical eraseblock number to check
* @offset: the starting offset within the physical eraseblock to check
@@ -1239,8 +1275,7 @@ exit:
* @offset of the physical eraseblock @pnum, %1 if not, and a negative error
* code if an error occurred.
*/
-static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
- int len)
+int ubi_dbg_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
{
size_t read;
int err;
@@ -1276,74 +1311,4 @@ error:
return err;
}
-/**
- * paranoid_check_empty - whether a PEB is empty.
- * @ubi: UBI device description object
- * @pnum: the physical eraseblock number to check
- *
- * This function makes sure PEB @pnum is empty, which means it contains only
- * %0xFF data bytes. Returns zero if the PEB is empty, %1 if not, and a
- * negative error code in case of failure.
- *
- * Empty PEBs have the EC header, and do not have the VID header. The caller of
- * this function should have already made sure the PEB does not have the VID
- * header. However, this function re-checks that, because it is possible that
- * the header and data has already been written to the PEB.
- *
- * Let's consider a possible scenario. Suppose there are 2 tasks - A and B.
- * Task A is in 'wear_leveling_worker()'. It is reading VID header of PEB X to
- * find which LEB it corresponds to. PEB X is currently unmapped, and has no
- * VID header. Task B is trying to write to PEB X.
- *
- * Task A: in 'ubi_io_read_vid_hdr()': reads the VID header from PEB X. The
- * read data contain all 0xFF bytes;
- * Task B: writes VID header and some data to PEB X;
- * Task A: assumes PEB X is empty, calls 'paranoid_check_empty()'. And if we
- * do not re-read the VID header, and do not cancel the checking if it
- * is there, we fail.
- */
-static int paranoid_check_empty(struct ubi_device *ubi, int pnum)
-{
- int err, offs = ubi->vid_hdr_aloffset, len = ubi->vid_hdr_alsize;
- size_t read;
- uint32_t magic;
- const struct ubi_vid_hdr *vid_hdr;
-
- mutex_lock(&ubi->dbg_buf_mutex);
- err = ubi->mtd->read(ubi->mtd, offs, len, &read, ubi->dbg_peb_buf);
- if (err && err != -EUCLEAN) {
- ubi_err("error %d while reading %d bytes from PEB %d:%d, "
- "read %zd bytes", err, len, pnum, offs, read);
- goto error;
- }
-
- vid_hdr = ubi->dbg_peb_buf;
- magic = be32_to_cpu(vid_hdr->magic);
- if (magic == UBI_VID_HDR_MAGIC)
- /* The PEB contains VID header, so it is not empty */
- goto out;
-
- err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
- if (err == 0) {
- ubi_err("flash region at PEB %d:%d, length %d does not "
- "contain all 0xFF bytes", pnum, offs, len);
- goto fail;
- }
-
-out:
- mutex_unlock(&ubi->dbg_buf_mutex);
- return 0;
-
-fail:
- ubi_err("paranoid check failed for PEB %d", pnum);
- ubi_msg("hex dump of the %d-%d region", offs, offs + len);
- print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
- ubi->dbg_peb_buf, len, 1);
- err = 1;
-error:
- ubi_dbg_dump_stack();
- mutex_unlock(&ubi->dbg_buf_mutex);
- return err;
-}
-
#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */