target/linux/ar71xx/patches-3.3/406-mtd-m25p80-allow-to-specify-max-read-size.patch

   1 --- a/drivers/mtd/devices/m25p80.c
   2 +++ b/drivers/mtd/devices/m25p80.c
   3 @@ -100,6 +100,7 @@ struct m25p {
   4         u16                     addr_width;
   5         u8                      erase_opcode;
   6         u8                      *command;
   7 +       size_t                  max_read_len;
   8  };
   9
  10  static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
  11 @@ -352,6 +353,7 @@ static int m25p80_read(struct mtd_info *
  12         struct m25p *flash = mtd_to_m25p(mtd);
  13         struct spi_transfer t[2];
  14         struct spi_message m;
  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 @@ -374,8 +376,6 @@ static int m25p80_read(struct mtd_info *
  20         t[0].len = m25p_cmdsz(flash) + FAST_READ_DUMMY_BYTE;
  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         /* Byte count starts at zero. */
  28 @@ -383,13 +383,6 @@ static int m25p80_read(struct mtd_info *
  29
  30         mutex_lock(&flash->lock);
  31
  32 -       /* Wait till previous write/erase is done. */
  33 -       if (wait_till_ready(flash)) {
  34 -               /* REVISIT status return?? */
  35 -               mutex_unlock(&flash->lock);
  36 -               return 1;
  37 -       }
  38 -
  39         /* FIXME switch to OPCODE_FAST_READ.  It's required for higher
  40          * clocks; and at this writing, every chip this driver handles
  41          * supports that opcode.
  42 @@ -397,11 +390,44 @@ static int m25p80_read(struct mtd_info *
  43
  44         /* Set up the write data buffer. */
  45         flash->command[0] = OPCODE_READ;
  46 -       m25p_addr2cmd(flash, from, flash->command);
  47
  48 -       spi_sync(flash->spi, &m);
  49 +       ofs = 0;
  50 +       while (len) {
  51 +               size_t readlen;
  52 +               size_t done;
  53 +               int ret;
  54 +
  55 +               ret = wait_till_ready(flash);
  56 +               if (ret) {
  57 +                       mutex_unlock(&flash->lock);
  58 +                       return 1;
  59 +               }
  60 +
  61 +               if (flash->max_read_len > 0 &&
  62 +                   flash->max_read_len < len)
  63 +                       readlen = flash->max_read_len;
  64 +               else
  65 +                       readlen = len;
  66 +
  67 +               t[1].rx_buf = buf + ofs;
  68 +               t[1].len = readlen;
  69 +
  70 +               m25p_addr2cmd(flash, from + ofs, flash->command);
  71 +
  72 +               spi_sync(flash->spi, &m);
  73
  74 -       *retlen = m.actual_length - m25p_cmdsz(flash) - FAST_READ_DUMMY_BYTE;
  75 +               done = m.actual_length - m25p_cmdsz(flash) -
  76 +                      FAST_READ_DUMMY_BYTE;
  77 +               if (done != readlen) {
  78 +                       mutex_unlock(&flash->lock);
  79 +                       return 1;
  80 +               }
  81 +
  82 +               ofs += done;
  83 +               len -= done;
  84 +       }
  85 +
  86 +       *retlen = ofs;
  87
  88         mutex_unlock(&flash->lock);
  89
  90 @@ -924,6 +950,12 @@ static int __devinit m25p_probe(struct s
  91         flash->mtd.erase = m25p80_erase;
  92         flash->mtd.read = m25p80_read;
  93
  94 +       if (data && data->max_read_len) {
  95 +               flash->max_read_len = data->max_read_len;
  96 +               dev_warn(&spi->dev, "max_read_len set to %d bytes\n",
  97 +                       flash->max_read_len);
  98 +       }
  99 +
 100         /* sst flash chips use AAI word program */
 101         if (JEDEC_MFR(info->jedec_id) == CFI_MFR_SST)
 102                 flash->mtd.write = sst_write;
 103 --- a/include/linux/spi/flash.h
 104 +++ b/include/linux/spi/flash.h
 105 @@ -25,6 +25,7 @@ struct flash_platform_data {
 106
 107         char            *type;
 108
 109 +       size_t          max_read_len;
 110         /* we'll likely add more ... use JEDEC IDs, etc */
 111  };
 112