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mtd: rawnand: marvell: rework BCH engine failure path 

We are about to support a new layout that triggers a faulty mechanism in
BCH engine that creates bitflips in erased pages.

Before adding the quirk that will workaround this issue, this patch just
reworks a bit the section that handles ECC failures in BCH read path.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
This commit is contained in:
Miquel Raynal 2018-07-19 16:54:23 +02:00
parent e4cdf9cb32
commit dbfc671856
1 changed files with 40 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
drivers/mtd/nand/raw/marvell_nand.c
View File

@ -1295,11 +1295,11 @@ static int marvell_nfc_hw_ecc_bch_read_page(struct nand_chip *chip,
{
struct mtd_info *mtd = nand_to_mtd(chip);
const struct marvell_hw_ecc_layout *lt = to_marvell_nand(chip)->layout;
int data_len = lt->data_bytes, spare_len = lt->spare_bytes, ecc_len;
u8 *data = buf, *spare = chip->oob_poi, *ecc;
int data_len = lt->data_bytes, spare_len = lt->spare_bytes;
u8 *data = buf, *spare = chip->oob_poi;
int max_bitflips = 0;
u32 failure_mask = 0;
int chunk, ecc_offset_in_page, ret;
int chunk, ret;
/*
* With BCH, OOB is not fully used (and thus not read entirely), not
@ -1340,46 +1340,57 @@ static int marvell_nfc_hw_ecc_bch_read_page(struct nand_chip *chip,
* the controller in normal mode and must be re-read in raw mode. To
* avoid dropping the performances, we prefer not to include them. The
* user should re-read the page in raw mode if ECC bytes are required.
*/
/*
* In case there is any subpage read error reported by ->correct(), we
* usually re-read only ECC bytes in raw mode and check if the whole
* page is empty. In this case, it is normal that the ECC check failed
* and we just ignore the error.
*
* However, for any subpage read error reported by ->correct(), the ECC
* bytes must be read in raw mode and the full subpage must be checked
* to see if it is entirely empty of if there was an actual error.
*/
for (chunk = 0; chunk < lt->nchunks; chunk++) {
int data_off_in_page, spare_off_in_page, ecc_off_in_page;
int data_off, spare_off, ecc_off;
int data_len, spare_len, ecc_len;
/* No failure reported for this chunk, move to the next one */
if (!(failure_mask & BIT(chunk)))
continue;
/* Derive ECC bytes positions (in page/buffer) and length */
ecc = chip->oob_poi +
(lt->full_chunk_cnt * lt->spare_bytes) +
lt->last_spare_bytes +
(chunk * ALIGN(lt->ecc_bytes, 32));
ecc_offset_in_page =
(chunk * (lt->data_bytes + lt->spare_bytes +
lt->ecc_bytes)) +
(chunk < lt->full_chunk_cnt ?
lt->data_bytes + lt->spare_bytes :
lt->last_data_bytes + lt->last_spare_bytes);
ecc_len = chunk < lt->full_chunk_cnt ?
lt->ecc_bytes : lt->last_ecc_bytes;
data_off_in_page = chunk * (lt->data_bytes + lt->spare_bytes +
lt->ecc_bytes);
spare_off_in_page = data_off_in_page +
(chunk < lt->full_chunk_cnt ? lt->data_bytes :
lt->last_data_bytes);
ecc_off_in_page = spare_off_in_page +
(chunk < lt->full_chunk_cnt ? lt->spare_bytes :
lt->last_spare_bytes);
/* Do the actual raw read of the ECC bytes */
nand_change_read_column_op(chip, ecc_offset_in_page,
ecc, ecc_len, false);
data_off = chunk * lt->data_bytes;
spare_off = chunk * lt->spare_bytes;
ecc_off = (lt->full_chunk_cnt * lt->spare_bytes) +
lt->last_spare_bytes +
(chunk * (lt->ecc_bytes + 2));
/* Derive data/spare bytes positions (in buffer) and length */
data = buf + (chunk * lt->data_bytes);
data_len = chunk < lt->full_chunk_cnt ?
lt->data_bytes : lt->last_data_bytes;
spare = chip->oob_poi + (chunk * (lt->spare_bytes +
lt->ecc_bytes));
spare_len = chunk < lt->full_chunk_cnt ?
lt->spare_bytes : lt->last_spare_bytes;
data_len = chunk < lt->full_chunk_cnt ? lt->data_bytes :
lt->last_data_bytes;
spare_len = chunk < lt->full_chunk_cnt ? lt->spare_bytes :
lt->last_spare_bytes;
ecc_len = chunk < lt->full_chunk_cnt ? lt->ecc_bytes :
lt->last_ecc_bytes;
nand_change_read_column_op(chip, ecc_off_in_page,
chip->oob_poi + ecc_off, ecc_len,
false);
/* Check the entire chunk (data + spare + ecc) for emptyness */
marvell_nfc_check_empty_chunk(chip, data, data_len, spare,
spare_len, ecc, ecc_len,
marvell_nfc_check_empty_chunk(chip, buf + data_off, data_len,
chip->oob_poi + spare_off, spare_len,
chip->oob_poi + ecc_off, ecc_len,
&max_bitflips);
}