target/linux/generic/backport-5.15/423-v6.1-0003-mtd-add-ECC-error-accounting-for-each-read-request.patch

   1 From 2ed18d818d1f7492172f8dd5904344c7d367e8ed Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <kernel@kempniu.pl>
   3 Date: Wed, 29 Jun 2022 14:57:36 +0200
   4 Subject: [PATCH 3/4] mtd: add ECC error accounting for each read request
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Extend struct mtd_req_stats with two new fields holding the number of
  10 corrected bitflips and uncorrectable errors detected during a read
  11 operation.  This is a prerequisite for ultimately passing those counters
  12 to user space, where they can be useful to applications for making
  13 better-informed choices about moving data around.
  14
  15 Unlike 'max_bitflips' (which is set - in a common code path - to the
  16 return value of a function called while the MTD device's mutex is held),
  17 these counters have to be maintained in each MTD driver which defines
  18 the '_read_oob' callback because the statistics need to be calculated
  19 while the MTD device's mutex is held.
  20
  21 Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
  22 Signed-off-by: Michał Kępień <kernel@kempniu.pl>
  23 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  24 Link: https://lore.kernel.org/linux-mtd/20220629125737.14418-4-kernel@kempniu.pl
  25 ---
  26  drivers/mtd/devices/docg3.c             |  8 ++++++++
  27  drivers/mtd/nand/onenand/onenand_base.c | 12 ++++++++++++
  28  drivers/mtd/nand/raw/nand_base.c        | 10 ++++++++++
  29  drivers/mtd/nand/spi/core.c             | 10 ++++++++++
  30  include/linux/mtd/mtd.h                 |  2 ++
  31  5 files changed, 42 insertions(+)
  32
  33 --- a/drivers/mtd/devices/docg3.c
  34 +++ b/drivers/mtd/devices/docg3.c
  35 @@ -871,6 +871,7 @@ static int doc_read_oob(struct mtd_info
  36         u8 *buf = ops->datbuf;
  37         size_t len, ooblen, nbdata, nboob;
  38         u8 hwecc[DOC_ECC_BCH_SIZE], eccconf1;
  39 +       struct mtd_ecc_stats old_stats;
  40         int max_bitflips = 0;
  41
  42         if (buf)
  43 @@ -895,6 +896,7 @@ static int doc_read_oob(struct mtd_info
  44         ret = 0;
  45         skip = from % DOC_LAYOUT_PAGE_SIZE;
  46         mutex_lock(&docg3->cascade->lock);
  47 +       old_stats = mtd->ecc_stats;
  48         while (ret >= 0 && (len > 0 || ooblen > 0)) {
  49                 calc_block_sector(from - skip, &block0, &block1, &page, &ofs,
  50                         docg3->reliable);
  51 @@ -966,6 +968,12 @@ static int doc_read_oob(struct mtd_info
  52         }
  53
  54  out:
  55 +       if (ops->stats) {
  56 +               ops->stats->uncorrectable_errors +=
  57 +                       mtd->ecc_stats.failed - old_stats.failed;
  58 +               ops->stats->corrected_bitflips +=
  59 +                       mtd->ecc_stats.corrected - old_stats.corrected;
  60 +       }
  61         mutex_unlock(&docg3->cascade->lock);
  62         return ret;
  63  err_in_read:
  64 --- a/drivers/mtd/nand/onenand/onenand_base.c
  65 +++ b/drivers/mtd/nand/onenand/onenand_base.c
  66 @@ -1440,6 +1440,7 @@ static int onenand_read_oob(struct mtd_i
  67                             struct mtd_oob_ops *ops)
  68  {
  69         struct onenand_chip *this = mtd->priv;
  70 +       struct mtd_ecc_stats old_stats;
  71         int ret;
  72
  73         switch (ops->mode) {
  74 @@ -1453,12 +1454,23 @@ static int onenand_read_oob(struct mtd_i
  75         }
  76
  77         onenand_get_device(mtd, FL_READING);
  78 +
  79 +       old_stats = mtd->ecc_stats;
  80 +
  81         if (ops->datbuf)
  82                 ret = ONENAND_IS_4KB_PAGE(this) ?
  83                         onenand_mlc_read_ops_nolock(mtd, from, ops) :
  84                         onenand_read_ops_nolock(mtd, from, ops);
  85         else
  86                 ret = onenand_read_oob_nolock(mtd, from, ops);
  87 +
  88 +       if (ops->stats) {
  89 +               ops->stats->uncorrectable_errors +=
  90 +                       mtd->ecc_stats.failed - old_stats.failed;
  91 +               ops->stats->corrected_bitflips +=
  92 +                       mtd->ecc_stats.corrected - old_stats.corrected;
  93 +       }
  94 +
  95         onenand_release_device(mtd);
  96
  97         return ret;
  98 --- a/drivers/mtd/nand/raw/nand_base.c
  99 +++ b/drivers/mtd/nand/raw/nand_base.c
 100 @@ -3815,6 +3815,7 @@ static int nand_read_oob(struct mtd_info
 101                          struct mtd_oob_ops *ops)
 102  {
 103         struct nand_chip *chip = mtd_to_nand(mtd);
 104 +       struct mtd_ecc_stats old_stats;
 105         int ret;
 106
 107         ops->retlen = 0;
 108 @@ -3826,11 +3827,20 @@ static int nand_read_oob(struct mtd_info
 109
 110         nand_get_device(chip);
 111
 112 +       old_stats = mtd->ecc_stats;
 113 +
 114         if (!ops->datbuf)
 115                 ret = nand_do_read_oob(chip, from, ops);
 116         else
 117                 ret = nand_do_read_ops(chip, from, ops);
 118
 119 +       if (ops->stats) {
 120 +               ops->stats->uncorrectable_errors +=
 121 +                       mtd->ecc_stats.failed - old_stats.failed;
 122 +               ops->stats->corrected_bitflips +=
 123 +                       mtd->ecc_stats.corrected - old_stats.corrected;
 124 +       }
 125 +
 126         nand_release_device(chip);
 127         return ret;
 128  }
 129 --- a/drivers/mtd/nand/spi/core.c
 130 +++ b/drivers/mtd/nand/spi/core.c
 131 @@ -629,6 +629,7 @@ static int spinand_mtd_read(struct mtd_i
 132  {
 133         struct spinand_device *spinand = mtd_to_spinand(mtd);
 134         struct nand_device *nand = mtd_to_nanddev(mtd);
 135 +       struct mtd_ecc_stats old_stats;
 136         unsigned int max_bitflips = 0;
 137         struct nand_io_iter iter;
 138         bool disable_ecc = false;
 139 @@ -640,6 +641,8 @@ static int spinand_mtd_read(struct mtd_i
 140
 141         mutex_lock(&spinand->lock);
 142
 143 +       old_stats = mtd->ecc_stats;
 144 +
 145         nanddev_io_for_each_page(nand, NAND_PAGE_READ, from, ops, &iter) {
 146                 if (disable_ecc)
 147                         iter.req.mode = MTD_OPS_RAW;
 148 @@ -662,6 +665,13 @@ static int spinand_mtd_read(struct mtd_i
 149                 ops->oobretlen += iter.req.ooblen;
 150         }
 151
 152 +       if (ops->stats) {
 153 +               ops->stats->uncorrectable_errors +=
 154 +                       mtd->ecc_stats.failed - old_stats.failed;
 155 +               ops->stats->corrected_bitflips +=
 156 +                       mtd->ecc_stats.corrected - old_stats.corrected;
 157 +       }
 158 +
 159         mutex_unlock(&spinand->lock);
 160
 161         if (ecc_failed && !ret)
 162 --- a/include/linux/mtd/mtd.h
 163 +++ b/include/linux/mtd/mtd.h
 164 @@ -41,6 +41,8 @@ struct mtd_erase_region_info {
 165  };
 166
 167  struct mtd_req_stats {
 168 +       unsigned int uncorrectable_errors;
 169 +       unsigned int corrected_bitflips;
 170         unsigned int max_bitflips;
 171  };
 172