diff --git a/Documentation/ABI/testing/sysfs-class-mtd b/Documentation/ABI/testing/sysfs-class-mtd
index 78835080856a9dc17df3b40857bb2dfa08d54277..db1ad7e34fc3a00e14be0c1045564fe6c98bd37e 100644
--- a/Documentation/ABI/testing/sysfs-class-mtd
+++ b/Documentation/ABI/testing/sysfs-class-mtd
@@ -167,7 +167,10 @@ Description:
block degradation, but high enough to avoid the consequences of
a persistent return value of -EUCLEAN on devices where sticky
bitflips occur. Note that if bitflip_threshold exceeds
- ecc_strength, -EUCLEAN is never returned by the read functions.
+ ecc_strength, -EUCLEAN is never returned by mtd_read().
+ Conversely, if bitflip_threshold is zero, -EUCLEAN is always
+ returned, absent a hard error.
This is generally applicable only to NAND flash devices with ECC
- capability. It is ignored on devices lacking ECC capability.
+ capability. It is ignored on devices lacking ECC capability;
+ i.e., devices for which ecc_strength is zero.
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 8272c02668d6ebccf54ad75b71da07158fd617be..65d22a0439c63b455d9baaac3136ba57e57ad7e7 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -850,6 +850,7 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
u8 *buf = ops->datbuf;
size_t len, ooblen, nbdata, nboob;
u8 hwecc[DOC_ECC_BCH_SIZE], eccconf1;
+ int max_bitflips = 0;
if (buf)
len = ops->len;
@@ -876,7 +877,7 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
ret = 0;
skip = from % DOC_LAYOUT_PAGE_SIZE;
mutex_lock(&docg3->cascade->lock);
- while (!ret && (len > 0 || ooblen > 0)) {
+ while (ret >= 0 && (len > 0 || ooblen > 0)) {
calc_block_sector(from - skip, &block0, &block1, &page, &ofs,
docg3->reliable);
nbdata = min_t(size_t, len, DOC_LAYOUT_PAGE_SIZE - skip);
@@ -936,7 +937,8 @@ static int doc_read_oob(struct mtd_info *mtd, loff_t from,
}
if (ret > 0) {
mtd->ecc_stats.corrected += ret;
- ret = -EUCLEAN;
+ max_bitflips = max(max_bitflips, ret);
+ ret = max_bitflips;
}
}
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 6a7cba1e24e61fbff8965744923005e18c835319..575730744fdb3ce83dc8e4a78cf65cefb3413fdc 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -800,12 +800,24 @@ EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
u_char *buf)
{
+ int ret_code;
*retlen = 0;
if (from < 0 || from > mtd->size || len > mtd->size - from)
return -EINVAL;
if (!len)
return 0;
- return mtd->_read(mtd, from, len, retlen, buf);
+
+ /*
+ * In the absence of an error, drivers return a non-negative integer
+ * representing the maximum number of bitflips that were corrected on
+ * any one ecc region (if applicable; zero otherwise).
+ */
+ ret_code = mtd->_read(mtd, from, len, retlen, buf);
+ if (unlikely(ret_code < 0))
+ return ret_code;
+ if (mtd->ecc_strength == 0)
+ return 0; /* device lacks ecc */
+ return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
EXPORT_SYMBOL_GPL(mtd_read);
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index ec75d44e0253c3885df7aa90764ead18e027dca9..d518e4db8a0bf8665156fd2383ad40fcde0fe146 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -67,12 +67,12 @@ static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
stats = part->master->ecc_stats;
res = part->master->_read(part->master, from + part->offset, len,
retlen, buf);
- if (unlikely(res)) {
- if (mtd_is_bitflip(res))
- mtd->ecc_stats.corrected += part->master->ecc_stats.corrected - stats.corrected;
- if (mtd_is_eccerr(res))
- mtd->ecc_stats.failed += part->master->ecc_stats.failed - stats.failed;
- }
+ if (unlikely(mtd_is_eccerr(res)))
+ mtd->ecc_stats.failed +=
+ part->master->ecc_stats.failed - stats.failed;
+ else
+ mtd->ecc_stats.corrected +=
+ part->master->ecc_stats.corrected - stats.corrected;
return res;
}
diff --git a/drivers/mtd/nand/alauda.c b/drivers/mtd/nand/alauda.c
index 4f20e1d8bef10b43546bd64d51933c0ed010093d..60a0dfdb08087a55311ee7f2e53522ecde7baa17 100644
--- a/drivers/mtd/nand/alauda.c
+++ b/drivers/mtd/nand/alauda.c
@@ -414,7 +414,7 @@ static int alauda_bounce_read(struct mtd_info *mtd, loff_t from, size_t len,
}
err = 0;
if (corrected)
- err = -EUCLEAN;
+ err = 1; /* return max_bitflips per ecc step */
if (uncorrected)
err = -EBADMSG;
out:
@@ -446,7 +446,7 @@ static int alauda_read(struct mtd_info *mtd, loff_t from, size_t len,
}
err = 0;
if (corrected)
- err = -EUCLEAN;
+ err = 1; /* return max_bitflips per ecc step */
if (uncorrected)
err = -EBADMSG;
return err;
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 9f5d339a361090b311f7271417417f8b70f02567..640f1f8159e8df3defad649b335ed25f296a2233 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1486,6 +1486,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
mtd->oobavail : mtd->oobsize;
uint8_t *bufpoi, *oob, *buf;
+ unsigned int max_bitflips = 0;
stats = mtd->ecc_stats;
@@ -1513,7 +1514,10 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
sndcmd = 0;
}
- /* Now read the page into the buffer */
+ /*
+ * Now read the page into the buffer. Absent an error,
+ * the read methods return max bitflips per ecc step.
+ */
if (unlikely(ops->mode == MTD_OPS_RAW))
ret = chip->ecc.read_page_raw(mtd, chip,
bufpoi, page);
@@ -1530,15 +1534,19 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
break;
}
+ max_bitflips = max_t(unsigned int, max_bitflips, ret);
+
/* Transfer not aligned data */
if (!aligned) {
if (!NAND_SUBPAGE_READ(chip) && !oob &&
!(mtd->ecc_stats.failed - stats.failed) &&
- (ops->mode != MTD_OPS_RAW))
+ (ops->mode != MTD_OPS_RAW)) {
chip->pagebuf = realpage;
- else
+ chip->pagebuf_bitflips = ret;
+ } else {
/* Invalidate page cache */
chip->pagebuf = -1;
+ }
memcpy(buf, chip->buffers->databuf + col, bytes);
}
@@ -1571,6 +1579,8 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
} else {
memcpy(buf, chip->buffers->databuf + col, bytes);
buf += bytes;
+ max_bitflips = max_t(unsigned int, max_bitflips,
+ chip->pagebuf_bitflips);
}
readlen -= bytes;
@@ -1609,7 +1619,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
if (mtd->ecc_stats.failed - stats.failed)
return -EBADMSG;
- return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
+ return max_bitflips;
}
/**
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index b3ce12ef359e83777280aff2b6f9fa9d58cc4dc9..7153e0d27101e3eed06ac17addcdbd4734c7ccc3 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -1201,7 +1201,8 @@ static int onenand_mlc_read_ops_nolock(struct mtd_info *mtd, loff_t from,
if (mtd->ecc_stats.failed - stats.failed)
return -EBADMSG;
- return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
+ /* return max bitflips per ecc step; ONENANDs correct 1 bit only */
+ return mtd->ecc_stats.corrected != stats.corrected ? 1 : 0;
}
/**
@@ -1333,7 +1334,8 @@ static int onenand_read_ops_nolock(struct mtd_info *mtd, loff_t from,
if (mtd->ecc_stats.failed - stats.failed)
return -EBADMSG;
- return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
+ /* return max bitflips per ecc step; ONENANDs correct 1 bit only */
+ return mtd->ecc_stats.corrected != stats.corrected ? 1 : 0;
}
/**
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 1482340d3d9f5e0a6ba5d61a020b112320618362..2829e8be3a620771ff14c15e635d7fbcfd4fe5d6 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -459,6 +459,8 @@ struct nand_buffers {
* @pagemask: [INTERN] page number mask = number of (pages / chip) - 1
* @pagebuf: [INTERN] holds the pagenumber which is currently in
* data_buf.
+ * @pagebuf_bitflips: [INTERN] holds the bitflip count for the page which is
+ * currently in data_buf.
* @subpagesize: [INTERN] holds the subpagesize
* @onfi_version: [INTERN] holds the chip ONFI version (BCD encoded),
* non 0 if ONFI supported.
@@ -519,6 +521,7 @@ struct nand_chip {
uint64_t chipsize;
int pagemask;
int pagebuf;
+ unsigned int pagebuf_bitflips;
int subpagesize;
uint8_t cellinfo;
int badblockpos;