From edbc4540e02c201bdd4f4d498ebb6ed517fd36e2 Mon Sep 17 00:00:00 2001 From: Mike Dunn Date: Wed, 25 Apr 2012 12:06:11 -0700 Subject: mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The drivers' _read() method, absent an error, returns a non-negative integer indicating the maximum number of bit errors that were corrected in any one region comprising an ecc step. MTD returns -EUCLEAN if this is >= bitflip_threshold, 0 otherwise. If bitflip_threshold is zero, the comparison is not made since these devices lack ECC and always return zero in the non-error case (thanks Brian)¹. Note that this is a subtle change to the driver interface. This and the preceding patches in this set were tested with ubi on top of the nandsim and docg4 devices, running the ubi test io_basic from mtd-utils. ¹ http://lists.infradead.org/pipermail/linux-mtd/2012-March/040468.html Signed-off-by: Mike Dunn Acked-by: Robert Jarzmik Acked-by: Brian Norris Ivan Djelic Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- drivers/mtd/nand/alauda.c | 4 ++-- drivers/mtd/nand/nand_base.c | 18 ++++++++++++++---- 2 files changed, 16 insertions(+), 6 deletions(-) (limited to 'drivers/mtd/nand') diff --git a/drivers/mtd/nand/alauda.c b/drivers/mtd/nand/alauda.c index 4f20e1d8bef1..60a0dfdb0808 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 9f5d339a3610..640f1f8159e8 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; } /** -- cgit v1.2.3