target/linux/brcm63xx/patches-4.4/000-4.8-09-mtd-spi-nor-add-read-loop.patch

   1 From 26f9bcad29a6c240881bd4efc90f16a9990dd6c2 Mon Sep 17 00:00:00 2001
   2 From: Michal Suchanek <hramrach@gmail.com>
   3 Date: Thu, 5 May 2016 17:31:55 -0700
   4 Subject: [PATCH 09/10] mtd: spi-nor: add read loop
   5
   6 mtdblock and ubi do not handle the situation when read returns less data
   7 than requested. Loop in spi-nor until buffer is filled or an error is
   8 returned.
   9
  10 Signed-off-by: Michal Suchanek <hramrach@gmail.com>
  11 Signed-off-by: Brian Norris <computersforpeace@gmail.com>
  12 Tested-by Cyrille Pitchen <cyrille.pitchen@atmel.com>
  13 Acked-by: Michal Suchanek <hramrach@gmail.com>
  14 Tested-by: Michal Suchanek <hramrach@gmail.com>
  15 ---
  16  drivers/mtd/spi-nor/spi-nor.c | 25 +++++++++++++++++++------
  17  1 file changed, 19 insertions(+), 6 deletions(-)
  18
  19 --- a/drivers/mtd/spi-nor/spi-nor.c
  20 +++ b/drivers/mtd/spi-nor/spi-nor.c
  21 @@ -890,14 +890,27 @@ static int spi_nor_read(struct mtd_info
  22         if (ret)
  23                 return ret;
  24
  25 -       ret = nor->read(nor, from, len, buf);
  26 +       while (len) {
  27 +               ret = nor->read(nor, from, len, buf);
  28 +               if (ret == 0) {
  29 +                       /* We shouldn't see 0-length reads */
  30 +                       ret = -EIO;
  31 +                       goto read_err;
  32 +               }
  33 +               if (ret < 0)
  34 +                       goto read_err;
  35
  36 -       spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
  37 -       if (ret < 0)
  38 -               return ret;
  39 +               WARN_ON(ret > len);
  40 +               *retlen += ret;
  41 +               buf += ret;
  42 +               from += ret;
  43 +               len -= ret;
  44 +       }
  45 +       ret = 0;
  46
  47 -       *retlen += ret;
  48 -       return 0;
  49 +read_err:
  50 +       spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
  51 +       return ret;
  52  }
  53
  54  static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,