From: Mike Dunn Date: Wed, 25 Apr 2012 19:06:11 +0000 (-0700) Subject: mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN X-Git-Tag: next-20120430~51^2 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5568eb3c3bb2816281b6a7c04db92434b72b1495;p=karo-tx-linux.git mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN The drivers _read() method, absent an error, return 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 preceeding 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 Signed-off-by: Artem Bityutskiy --- diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c index 34140312ddd4..7644d59d72bf 100644 --- a/drivers/mtd/devices/docg3.c +++ b/drivers/mtd/devices/docg3.c @@ -862,6 +862,7 @@ 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; @@ -948,7 +949,8 @@ 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 6a7cba1e24e6..b5bb628760d4 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->bitflip_threshold == 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 ec75d44e0253..d518e4db8a0b 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 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; } /** diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c index b3ce12ef359e..7153e0d27101 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 1482340d3d9f..2829e8be3a62 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;