target/linux/ar71xx/patches-3.10/406-mtd-m25p80-allow-to-specify-max-read-size.patch

   1 --- a/drivers/mtd/devices/m25p80.c
   2 +++ b/drivers/mtd/devices/m25p80.c
   3 @@ -93,6 +93,7 @@ struct m25p {
   4         u8                      erase_opcode;
   5         u8                      *command;
   6         bool                    fast_read;
   7 +       size_t                  max_read_len;
   8  };
   9
  10  static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
  11 @@ -344,6 +345,7 @@ static int m25p80_read(struct mtd_info *
  12         struct spi_transfer t[2];
  13         struct spi_message m;
  14         uint8_t opcode;
  15 +       loff_t ofs;
  16
  17         pr_debug("%s: %s from 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
  18                         __func__, (u32)from, len);
  19 @@ -359,19 +361,10 @@ static int m25p80_read(struct mtd_info *
  20         t[0].len = m25p_cmdsz(flash) + (flash->fast_read ? 1 : 0);
  21         spi_message_add_tail(&t[0], &m);
  22
  23 -       t[1].rx_buf = buf;
  24 -       t[1].len = len;
  25         spi_message_add_tail(&t[1], &m);
  26
  27         mutex_lock(&flash->lock);
  28
  29 -       /* Wait till previous write/erase is done. */
  30 -       if (wait_till_ready(flash)) {
  31 -               /* REVISIT status return?? */
  32 -               mutex_unlock(&flash->lock);
  33 -               return 1;
  34 -       }
  35 -
  36         /* FIXME switch to OPCODE_FAST_READ.  It's required for higher
  37          * clocks; and at this writing, every chip this driver handles
  38          * supports that opcode.
  39 @@ -380,13 +373,43 @@ static int m25p80_read(struct mtd_info *
  40         /* Set up the write data buffer. */
  41         opcode = flash->fast_read ? OPCODE_FAST_READ : OPCODE_NORM_READ;
  42         flash->command[0] = opcode;
  43 -       m25p_addr2cmd(flash, from, flash->command);
  44 +       ofs = 0;
  45 +       while (len) {
  46 +               size_t readlen;
  47 +               size_t done;
  48 +               int ret;
  49 +
  50 +               ret = wait_till_ready(flash);
  51 +               if (ret) {
  52 +                       mutex_unlock(&flash->lock);
  53 +                       return 1;
  54 +               }
  55 +
  56 +               if (flash->max_read_len > 0 &&
  57 +                   flash->max_read_len < len)
  58 +                       readlen = flash->max_read_len;
  59 +               else
  60 +                       readlen = len;
  61 +
  62 +               t[1].rx_buf = buf + ofs;
  63 +               t[1].len = readlen;
  64 +
  65 +               m25p_addr2cmd(flash, from + ofs, flash->command);
  66 +
  67 +               spi_sync(flash->spi, &m);
  68
  69 -       spi_sync(flash->spi, &m);
  70 +               done = m.actual_length - m25p_cmdsz(flash) -
  71 +                      (flash->fast_read ? 1 : 0);
  72 +               if (done != readlen) {
  73 +                       mutex_unlock(&flash->lock);
  74 +                       return 1;
  75 +               }
  76
  77 -       *retlen = m.actual_length - m25p_cmdsz(flash) -
  78 -                       (flash->fast_read ? 1 : 0);
  79 +               ofs += done;
  80 +               len -= done;
  81 +       }
  82
  83 +       *retlen = ofs;
  84         mutex_unlock(&flash->lock);
  85
  86         return 0;
  87 @@ -1022,6 +1045,12 @@ static int m25p_probe(struct spi_device
  88                 flash->mtd._unlock = m25p80_unlock;
  89         }
  90
  91 +       if (data && data->max_read_len) {
  92 +               flash->max_read_len = data->max_read_len;
  93 +               dev_warn(&spi->dev, "max_read_len set to %d bytes\n",
  94 +                       flash->max_read_len);
  95 +       }
  96 +
  97         /* sst flash chips use AAI word program */
  98         if (info->flags & SST_WRITE)
  99                 flash->mtd._write = sst_write;
 100 --- a/include/linux/spi/flash.h
 101 +++ b/include/linux/spi/flash.h
 102 @@ -25,6 +25,7 @@ struct flash_platform_data {
 103
 104         char            *type;
 105
 106 +       size_t          max_read_len;
 107         /* we'll likely add more ... use JEDEC IDs, etc */
 108  };
 109