target/linux/ramips/patches-3.10/0131-mtd-add-chunked-read-io-to-m25p80.patch

   1 From f85e6dacdb7d7a9bc37f33cf8770006ab64286f7 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Wed, 27 Nov 2013 20:58:16 +0100
   4 Subject: [PATCH 131/133] mtd: add chunked read io to m25p80
   5
   6 Signed-off-by: John Crispin <blogic@openwrt.org>
   7 ---
   8  drivers/mtd/devices/m25p80.c |  127 ++++++++++++++++++++++++++++++++++++++++++
   9  1 file changed, 127 insertions(+)
  10
  11 Index: linux-3.10.34/drivers/mtd/devices/m25p80.c
  12 ===================================================================
  13 --- linux-3.10.34.orig/drivers/mtd/devices/m25p80.c     2014-03-30 19:40:10.135292951 +0100
  14 +++ linux-3.10.34/drivers/mtd/devices/m25p80.c  2014-03-30 19:44:40.151295482 +0100
  15 @@ -392,6 +392,58 @@
  16         return 0;
  17  }
  18
  19 +static int m25p80_read_chunked(struct mtd_info *mtd, loff_t from, size_t len,
  20 +       size_t *retlen, u_char *buf)
  21 +{
  22 +       struct m25p *flash = mtd_to_m25p(mtd);
  23 +       struct spi_transfer t[2];
  24 +       struct spi_message m;
  25 +       uint8_t opcode;
  26 +       int idx = 0;
  27 +
  28 +       pr_debug("%s: %s from 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
  29 +                       __func__, (u32)from, len);
  30 +
  31 +       spi_message_init(&m);
  32 +       memset(t, 0, (sizeof t));
  33 +
  34 +       t[0].tx_buf = flash->command;
  35 +       t[0].len = m25p_cmdsz(flash);
  36 +       spi_message_add_tail(&t[0], &m);
  37 +       spi_message_add_tail(&t[1], &m);
  38 +
  39 +       *retlen = 0;
  40 +
  41 +       while (idx < len) {
  42 +               int rlen = (len - idx > 4) ? (4) : (len - idx);
  43 +
  44 +               t[1].rx_buf = &buf[idx];
  45 +               t[1].len = rlen;
  46 +
  47 +               mutex_lock(&flash->lock);
  48 +
  49 +               /* Wait till previous write/erase is done. */
  50 +               if (wait_till_ready(flash)) {
  51 +                       /* REVISIT status return?? */
  52 +                       mutex_unlock(&flash->lock);
  53 +                       return 1;
  54 +               }
  55 +
  56 +               /* Set up the write data buffer. */
  57 +               opcode = OPCODE_NORM_READ;
  58 +               flash->command[0] = opcode;
  59 +               m25p_addr2cmd(flash, from + idx, flash->command);
  60 +
  61 +               spi_sync(flash->spi, &m);
  62 +
  63 +               *retlen += m.actual_length - m25p_cmdsz(flash);
  64 +
  65 +               mutex_unlock(&flash->lock);
  66 +               idx += rlen;
  67 +       }
  68 +       return 0;
  69 +}
  70 +
  71  /*
  72   * Write an address range to the flash chip.  Data must be written in
  73   * FLASH_PAGESIZE chunks.  The address range may be any size provided
  74 @@ -479,6 +531,76 @@
  75         return 0;
  76  }
  77
  78 +static int m25p80_write_chunked(struct mtd_info *mtd, loff_t to, size_t len,
  79 +       size_t *retlen, const u_char *buf)
  80 +{
  81 +       struct m25p *flash = mtd_to_m25p(mtd);
  82 +       struct spi_transfer t;
  83 +       struct spi_message m;
  84 +       u32 i, page_size;
  85 +       u8 tmp[8];
  86 +
  87 +       pr_debug("%s: %s to 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
  88 +                       __func__, (u32)to, len);
  89 +
  90 +       spi_message_init(&m);
  91 +       memset(&t, 0, (sizeof t));
  92 +
  93 +       t.tx_buf = tmp;
  94 +       t.len = 8;
  95 +       spi_message_add_tail(&t, &m);
  96 +
  97 +       mutex_lock(&flash->lock);
  98 +
  99 +       /* Wait until finished previous write command. */
 100 +       if (wait_till_ready(flash)) {
 101 +               mutex_unlock(&flash->lock);
 102 +               return 1;
 103 +       }
 104 +
 105 +       write_enable(flash);
 106 +
 107 +       /* Set up the opcode in the write buffer. */
 108 +       flash->command[0] = OPCODE_PP;
 109 +       m25p_addr2cmd(flash, to, flash->command);
 110 +
 111 +       t.len = 4 + (to & 0x3);
 112 +       if (t.len == 4)
 113 +               t.len = 8;
 114 +       memcpy(tmp, flash->command, 4);
 115 +       memcpy(&tmp[4], buf, t.len - 4);
 116 +       spi_sync(flash->spi, &m);
 117 +       page_size = t.len - 4;
 118 +
 119 +       *retlen = m.actual_length - m25p_cmdsz(flash);
 120 +
 121 +       /* write everything in flash->page_size chunks */
 122 +       for (i = page_size; i < len; i += page_size) {
 123 +               page_size = len - i;
 124 +               if (page_size > 4)
 125 +                       page_size = 4;
 126 +
 127 +               /* write the next page to flash */
 128 +               m25p_addr2cmd(flash, to + i, flash->command);
 129 +
 130 +               memcpy(tmp, flash->command, 4);
 131 +               memcpy(&tmp[4], buf + i, page_size);
 132 +               t.len = 4 + page_size;
 133 +
 134 +               wait_till_ready(flash);
 135 +
 136 +               write_enable(flash);
 137 +
 138 +               spi_sync(flash->spi, &m);
 139 +
 140 +               *retlen += m.actual_length - m25p_cmdsz(flash);
 141 +       }
 142 +
 143 +       mutex_unlock(&flash->lock);
 144 +
 145 +       return 0;
 146 +}
 147 +
 148  static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
 149                 size_t *retlen, const u_char *buf)
 150  {
 151 @@ -1058,6 +1180,12 @@
 152                 flash->fast_read = true;
 153  #endif
 154
 155 +       if (np && of_property_read_bool(np, "m25p,chunked-io")) {
 156 +               dev_warn(&spi->dev, "using chunked io\n");
 157 +               flash->mtd._read = m25p80_read_chunked;
 158 +               flash->mtd._write = m25p80_write_chunked;
 159 +       }
 160 +
 161  #ifdef CONFIG_M25PXX_USE_FAST_READ
 162         flash->fast_read = true;
 163  #endif