[PATCH v2] MTD: at91: atmel_nand: return bit flips for the PMECC read_page()
Josh Wu
josh.wu at atmel.com
Tue Nov 27 05:50:31 EST 2012
This patch fix pmecc's read_page() to return maximum number of bitflips, 0 if uncorrectable.
In the commit: 3f91e94f7f511de74c0d2abe08672ccdbdd1961c ("mtd: nand: read_page() returns max_bitflips ()"),
The ecc.read_page() is changed to return the maximum number of bitflips.
And when meet uncorrectable bitflips it needs to return 0.
See the comment in nand.h:
* @read_page: function to read a page according to the ECC generator
* requirements; returns maximum number of bitflips corrected in
* any single ECC step, 0 if bitflips uncorrectable, -EIO hw error
Signed-off-by: Josh Wu <josh.wu at atmel.com>
---
change since v1:
1. add detail commit message for the fix.
2. return 0 when meet uncorrectable bitflips according to Mike Dunn's suggestion.
drivers/mtd/nand/atmel_nand.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index c918386..1669d27 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -723,6 +723,7 @@ static int pmecc_correction(struct mtd_info *mtd, u32 pmecc_stat, uint8_t *buf,
struct atmel_nand_host *host = nand_chip->priv;
int i, err_nbr, eccbytes;
uint8_t *buf_pos;
+ int total_err = 0;
eccbytes = nand_chip->ecc.bytes;
for (i = 0; i < eccbytes; i++)
@@ -750,12 +751,13 @@ normal_check:
pmecc_correct_data(mtd, buf_pos, ecc, i,
host->pmecc_bytes_per_sector, err_nbr);
mtd->ecc_stats.corrected += err_nbr;
+ total_err += err_nbr;
}
}
pmecc_stat >>= 1;
}
- return 0;
+ return total_err;
}
static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
@@ -767,6 +769,7 @@ static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
uint32_t *eccpos = chip->ecc.layout->eccpos;
uint32_t stat;
unsigned long end_time;
+ int bitflips = 0;
pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
@@ -789,11 +792,14 @@ static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
}
stat = pmecc_readl_relaxed(host->ecc, ISR);
- if (stat != 0)
- if (pmecc_correction(mtd, stat, buf, &oob[eccpos[0]]) != 0)
- return -EIO;
+ if (stat != 0) {
+ bitflips = pmecc_correction(mtd, stat, buf, &oob[eccpos[0]]);
+ if (bitflips < 0)
+ /* uncorrectable errors */
+ return 0;
+ }
- return 0;
+ return bitflips;
}
static int atmel_nand_pmecc_write_page(struct mtd_info *mtd,
--
1.7.9.5
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