target/linux/brcm63xx/patches-3.10/203-MTD-DEVICES-m25p80-add-support-for-limiting-reads.patch

   1 From 5fb4e8d7287ac8fcb33aae8b1e9e22c5a3c392bd Mon Sep 17 00:00:00 2001
   2 From: Jonas Gorski <jonas.gorski@gmail.com>
   3 Date: Thu, 10 Nov 2011 17:33:40 +0100
   4 Subject: [PATCH 51/79] MTD: DEVICES: m25p80: add support for limiting reads
   5
   6 Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
   7 ---
   8  drivers/mtd/devices/m25p80.c |   29 +++++++++++++++++++++++++++--
   9  include/linux/spi/flash.h    |    4 ++++
  10  2 files changed, 31 insertions(+), 2 deletions(-)
  11
  12 --- a/drivers/mtd/devices/m25p80.c
  13 +++ b/drivers/mtd/devices/m25p80.c
  14 @@ -93,6 +93,7 @@ struct m25p {
  15         u8                      erase_opcode;
  16         u8                      *command;
  17         bool                    fast_read;
  18 +       int                     max_transfer_len;
  19  };
  20
  21  static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
  22 @@ -337,10 +338,9 @@ static int m25p80_erase(struct mtd_info
  23   * Read an address range from the flash chip.  The address range
  24   * may be any size provided it is within the physical boundaries.
  25   */
  26 -static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
  27 +static int __m25p80_read(struct m25p *flash, loff_t from, size_t len,
  28         size_t *retlen, u_char *buf)
  29  {
  30 -       struct m25p *flash = mtd_to_m25p(mtd);
  31         struct spi_transfer t[2];
  32         struct spi_message m;
  33         uint8_t opcode;
  34 @@ -392,6 +392,28 @@ static int m25p80_read(struct mtd_info *
  35         return 0;
  36  }
  37
  38 +static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
  39 +       size_t *retlen, u_char *buf)
  40 +{
  41 +       struct m25p *flash = mtd_to_m25p(mtd);
  42 +       size_t off;
  43 +       size_t read_len = flash->max_transfer_len;
  44 +       size_t part_len;
  45 +       int ret = 0;
  46 +
  47 +       if (!read_len)
  48 +               return __m25p80_read(flash, from, len, retlen, buf);
  49 +
  50 +       *retlen = 0;
  51 +
  52 +       for (off = 0; off < len && !ret; off += read_len) {
  53 +               ret = __m25p80_read(flash, from + off, min(len - off, read_len),
  54 +                                   &part_len, buf + off);
  55 +                       *retlen += part_len;
  56 +       }
  57 +
  58 +       return ret;
  59 +}
  60  /*
  61   * Write an address range to the flash chip.  Data must be written in
  62   * FLASH_PAGESIZE chunks.  The address range may be any size provided
  63 @@ -983,6 +1005,9 @@ static int m25p_probe(struct spi_device
  64                 return -ENOMEM;
  65         }
  66
  67 +       if (data)
  68 +               flash->max_transfer_len = data->max_transfer_len;
  69 +
  70         flash->spi = spi;
  71         mutex_init(&flash->lock);
  72         dev_set_drvdata(&spi->dev, flash);
  73 --- a/include/linux/spi/flash.h
  74 +++ b/include/linux/spi/flash.h
  75 @@ -13,6 +13,8 @@ struct mtd_part_parser_data;
  76   * @part_probe_types: optional list of MTD parser names to use for
  77   *     partitioning
  78   *
  79 + * @max_transfer_len: option maximum read/write length limitation for
  80 + *     SPI controllers not able to transfer any length commands.
  81   * Board init code (in arch/.../mach-xxx/board-yyy.c files) can
  82   * provide information about SPI flash parts (such as DataFlash) to
  83   * help set up the device and its appropriate default partitioning.
  84 @@ -28,6 +30,8 @@ struct flash_platform_data {
  85         char            *type;
  86
  87         const char      **part_probe_types;
  88 +
  89 +       unsigned int    max_transfer_len;
  90         /* we'll likely add more ... use JEDEC IDs, etc */
  91  };
  92