target/linux/ar71xx/patches-3.14/406-mtd-m25p80-allow-to-specify-max-read-size.patch

   1 --- a/drivers/mtd/devices/m25p80.c
   2 +++ b/drivers/mtd/devices/m25p80.c
   3 @@ -115,6 +115,7 @@ struct m25p {
   4         u8                      program_opcode;
   5         u8                      *command;
   6         enum read_type          flash_read;
   7 +       size_t                  max_read_len;
   8  };
   9
  10  static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
  11 @@ -517,6 +518,7 @@ static int m25p80_read(struct mtd_info *
  12         struct spi_message m;
  13         uint8_t opcode;
  14         int dummy;
  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 @@ -534,29 +536,51 @@ static int m25p80_read(struct mtd_info *
  20         t[0].len = m25p_cmdsz(flash) + dummy;
  21         spi_message_add_tail(&t[0], &m);
  22
  23 -       t[1].rx_buf = buf;
  24 -       t[1].rx_nbits = m25p80_rx_nbits(flash);
  25 -       t[1].len = len;
  26         spi_message_add_tail(&t[1], &m);
  27
  28         mutex_lock(&flash->lock);
  29
  30 -       /* Wait till previous write/erase is done. */
  31 -       if (wait_till_ready(flash)) {
  32 -               /* REVISIT status return?? */
  33 -               mutex_unlock(&flash->lock);
  34 -               return 1;
  35 -       }
  36 -
  37         /* Set up the write data buffer. */
  38         opcode = flash->read_opcode;
  39         flash->command[0] = opcode;
  40 -       m25p_addr2cmd(flash, from, flash->command);
  41 +       ofs = 0;
  42 +       while (len) {
  43 +               size_t readlen;
  44 +               size_t done;
  45 +               int ret;
  46
  47 -       spi_sync(flash->spi, &m);
  48 +               ret = wait_till_ready(flash);
  49 +               if (ret) {
  50 +                       mutex_unlock(&flash->lock);
  51 +                       return 1;
  52 +               }
  53 +
  54 +               if (flash->max_read_len > 0 &&
  55 +                   flash->max_read_len < len)
  56 +                       readlen = flash->max_read_len;
  57 +               else
  58 +                       readlen = len;
  59
  60 -       *retlen = m.actual_length - m25p_cmdsz(flash) - dummy;
  61 +               t[1].rx_buf = buf + ofs;
  62 +               t[1].rx_nbits = m25p80_rx_nbits(flash);
  63 +               t[1].len = readlen;
  64
  65 +               m25p_addr2cmd(flash, from + ofs, flash->command);
  66 +
  67 +               spi_sync(flash->spi, &m);
  68 +
  69 +               done = m.actual_length - m25p_cmdsz(flash) -
  70 +                      dummy;
  71 +               if (done != readlen) {
  72 +                       mutex_unlock(&flash->lock);
  73 +                       return 1;
  74 +               }
  75 +
  76 +               ofs += done;
  77 +               len -= done;
  78 +       }
  79 +
  80 +       *retlen = ofs;
  81         mutex_unlock(&flash->lock);
  82
  83         return 0;
  84 @@ -1193,6 +1217,12 @@ static int m25p_probe(struct spi_device
  85                 flash->mtd._unlock = m25p80_unlock;
  86         }
  87
  88 +       if (data && data->max_read_len) {
  89 +               flash->max_read_len = data->max_read_len;
  90 +               dev_warn(&spi->dev, "max_read_len set to %d bytes\n",
  91 +                       flash->max_read_len);
  92 +       }
  93 +
  94         /* sst flash chips use AAI word program */
  95         if (info->flags & SST_WRITE)
  96                 flash->mtd._write = sst_write;
  97 --- a/include/linux/spi/flash.h
  98 +++ b/include/linux/spi/flash.h
  99 @@ -25,6 +25,7 @@ struct flash_platform_data {
 100
 101         char            *type;
 102
 103 +       size_t          max_read_len;
 104         /* we'll likely add more ... use JEDEC IDs, etc */
 105  };
 106