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path: root/drivers/mtd/nand/nand_mxs.c
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Diffstat (limited to 'drivers/mtd/nand/nand_mxs.c')
-rw-r--r--drivers/mtd/nand/nand_mxs.c42
1 files changed, 40 insertions, 2 deletions
diff --git a/drivers/mtd/nand/nand_mxs.c b/drivers/mtd/nand/nand_mxs.c
index b3767e6..7635e2a 100644
--- a/drivers/mtd/nand/nand_mxs.c
+++ b/drivers/mtd/nand/nand_mxs.c
@@ -737,6 +737,8 @@ static int mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand,
/* Read DMA completed, now do the mark swapping. */
mxs_nand_swap_block_mark(mtd, nand_info->data_buf, nand_info->oob_buf);
+ memcpy(buf, nand_info->data_buf, mtd->writesize);
+
/* Loop over status bytes, accumulating ECC status. */
status = nand_info->oob_buf + mxs_nand_aux_status_offset();
for (i = 0; i < mxs_nand_ecc_chunk_cnt(mtd->writesize); i++) {
@@ -747,6 +749,44 @@ static int mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand,
continue;
if (status[i] == 0xfe) {
+ int flips;
+
+ /*
+ * The ECC hardware has an uncorrectable ECC status
+ * code in case we have bitflips in an erased page. As
+ * nothing was written into this subpage the ECC is
+ * obviously wrong and we can not trust it. We assume
+ * at this point that we are reading an erased page and
+ * try to correct the bitflips in buffer up to
+ * ecc_strength bitflips. If this is a page with random
+ * data, we exceed this number of bitflips and have a
+ * ECC failure. Otherwise we use the corrected buffer.
+ */
+ if (i == 0) {
+ /* The first block includes metadata */
+ flips = nand_check_erased_ecc_chunk(
+ buf + i * MXS_NAND_CHUNK_DATA_CHUNK_SIZE,
+ MXS_NAND_CHUNK_DATA_CHUNK_SIZE,
+ NULL, 0,
+ nand_info->oob_buf,
+ MXS_NAND_METADATA_SIZE,
+ mtd->ecc_strength);
+ } else {
+ flips = nand_check_erased_ecc_chunk(
+ buf + i * MXS_NAND_CHUNK_DATA_CHUNK_SIZE,
+ MXS_NAND_CHUNK_DATA_CHUNK_SIZE,
+ NULL, 0,
+ NULL, 0,
+ mtd->ecc_strength);
+ }
+
+ if (flips > 0) {
+ max_bitflips = max_t(unsigned int,
+ max_bitflips, flips);
+ corrected += flips;
+ continue;
+ }
+
failed++;
continue;
}
@@ -772,8 +812,6 @@ static int mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand,
nand->oob_poi[0] = nand_info->oob_buf[0];
- memcpy(buf, nand_info->data_buf, mtd->writesize);
-
ret = 0;
rtn:
mxs_nand_return_dma_descs(nand_info);