nand: Add a watch command
This is a debug command to monitor the retention state of the data on
the array. The command needs a duplication of the mtd_read_oob()
function to actually return the maximum number of bitflips encountered
while reading the page. We could write a specific implementation for the
Sunxi driver but this is probably enough.
nand watch <off> <size> - check an area for bitflips
nand watch.part <part> - check a partition for bitflips
nand watch.chip - check the whole device for bitflips
The output may be a bit verbose and could look like:
=> nand watch.chip
device 0 whole chip
size adjusted to 0xff60000 (5 bad blocks)
NAND watch for bitflips in area 0x0-0xff60000:
Page 0 (0x00000000) -> error -74
Page 1 (0x00000800) -> error -74
Page 2 (0x00001000) -> error -74
Page 3 (0x00001800) -> error -74
Page 4 (0x00002000) -> error -74
Page 5 (0x00002800) -> error -74
Page 6 (0x00003000) -> error -74
Page 7 (0x00003800) -> error -74
Page 8 (0x00004000) -> error -74
Page 9 (0x00004800) -> error -74
Page 10 (0x00005000) -> error -74
Page 11 (0x00005800) -> error -74
Page 12 (0x00006000) -> error -74
Page 13 (0x00006800) -> error -74
Page 14 (0x00007000) -> error -74
Page 15 (0x00007800) -> error -74
Page 16 (0x00008000) -> error -74
Page 17 (0x00008800) -> error -74
Page 18 (0x00009000) -> error -74
Page 19 (0x00009800) -> error -74
Page 20 (0x0000a000) -> error -74
Page 21 (0x0000a800) -> error -74
Page 22 (0x0000b000) -> error -74
Page 23 (0x0000b800) -> error -74
Page 1110 (0x0022b000) -> up to 1 bf/chunk
Page 1122 (0x00231000) -> up to 1 bf/chunk
Page 1132 (0x00236000) -> up to 1 bf/chunk
Page 1362 (0x002a9000) -> up to 1 bf/chunk
Page 4990 (0x009bf000) -> up to 1 bf/chunk
Page 5728 (0x00b30000) -> up to 1 bf/chunk
Page 7116 (0x00de6000) -> up to 1 bf/chunk
Page 7160 (0x00dfc000) -> up to 1 bf/chunk
Page 7494 (0x00ea3000) -> up to 1 bf/chunk
Page 10842 (0x0152d000) -> up to 1 bf/chunk
Page 11614 (0x016af000) -> up to 1 bf/chunk
Page 11970 (0x01761000) -> up to 1 bf/chunk
Page 12536 (0x0187c000) -> up to 1 bf/chunk
Page 12687 (0x018c7800) -> up to 1 bf/chunk
Page 14298 (0x01bed000) -> up to 1 bf/chunk
Page 18268 (0x023ae000) -> up to 1 bf/chunk
Page 18760 (0x024a4000) -> up to 1 bf/chunk
Page 21440 (0x029e0000) -> up to 1 bf/chunk
Page 22336 (0x02ba0000) -> up to 1 bf/chunk
Page 22592 (0x02c20000) -> up to 1 bf/chunk
Page 23872 (0x02ea0000) -> up to 1 bf/chunk
Page 27584 (0x035e0000) -> up to 1 bf/chunk
Page 35008 (0x04460000) -> up to 1 bf/chunk
Page 37184 (0x048a0000) -> up to 1 bf/chunk
Page 41728 (0x05180000) -> up to 1 bf/chunk
Page 42176 (0x05260000) -> up to 1 bf/chunk
Page 43200 (0x05460000) -> up to 1 bf/chunk
Page 43328 (0x054a0000) -> up to 1 bf/chunk
Page 45376 (0x058a0000) -> up to 1 bf/chunk
Page 47040 (0x05be0000) -> up to 1 bf/chunk
Page 47552 (0x05ce0000) -> up to 1 bf/chunk
Page 49344 (0x06060000) -> up to 1 bf/chunk
Page 49856 (0x06160000) -> up to 1 bf/chunk
Page 62784 (0x07aa0000) -> up to 1 bf/chunk
Page 65153 (0x07f40800) -> up to 1 bf/chunk
Page 65228 (0x07f66000) -> up to 1 bf/chunk
Page 65382 (0x07fb3000) -> up to 1 bf/chunk
Page 98624 (0x0c0a0000) -> up to 1 bf/chunk
Page 101952 (0x0c720000) -> up to 1 bf/chunk
Page 107584 (0x0d220000) -> up to 1 bf/chunk
Page 118208 (0x0e6e0000) -> up to 1 bf/chunk
Page 126656 (0x0f760000) -> up to 1 bf/chunk
Page 127680 (0x0f960000) -> up to 1 bf/chunk
Page 129920 (0x0fdc0000) -> up to 1 bf/chunk
Maximum number of bitflips: 1
Pages with bitflips: 44/130752
It is also possible to reduce the output with the .quiet suffix in order
to just show the summary.
=> nand watch.chip
device 0 whole chip
size adjusted to 0xff60000 (5 bad blocks)
NAND watch for bitflips in area 0x0-0xff60000:
Maximum number of bitflips: 1
Pages with bitflips: 44/130752
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 5bd64bd..3bfa5ae 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1124,6 +1124,28 @@
}
EXPORT_SYMBOL_GPL(mtd_read_oob);
+/* This is a bare copy of mtd_read_oob returning the actual number of bitflips */
+int mtd_read_oob_bf(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
+{
+ int ret_code;
+ ops->retlen = ops->oobretlen = 0;
+ if (!mtd->_read_oob)
+ return -EOPNOTSUPP;
+ /*
+ * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
+ * similar to mtd->_read(), returning a non-negative integer
+ * representing max bitflips. In other cases, mtd->_read_oob() may
+ * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
+ */
+ ret_code = mtd->_read_oob(mtd, from, ops);
+ if (unlikely(ret_code < 0))
+ return ret_code;
+ if (mtd->ecc_strength == 0)
+ return 0; /* device lacks ecc */
+ return ret_code;
+}
+EXPORT_SYMBOL_GPL(mtd_read_oob_bf);
+
int mtd_write_oob(struct mtd_info *mtd, loff_t to,
struct mtd_oob_ops *ops)
{