target/linux/brcm47xx/patches-3.10/053-mtd_bcm47xxsflash_writing_support.patch

   1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
   2 Subject: [RFC][PATCH] mtd: bcm47xxsflash: writing support
   3 Date: Wed, 22 May 2013 14:39:02 +0200
   4
   5 ---
   6  drivers/mtd/devices/bcm47xxsflash.c |  130 +++++++++++++++++++++++++++++++++--
   7  1 file changed, 126 insertions(+), 4 deletions(-)
   8
   9 --- a/drivers/mtd/devices/bcm47xxsflash.c
  10 +++ b/drivers/mtd/devices/bcm47xxsflash.c
  11 @@ -116,6 +116,127 @@ static int bcm47xxsflash_read(struct mtd
  12         return len;
  13  }
  14
  15 +static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
  16 +                                 const u_char *buf)
  17 +{
  18 +       struct bcm47xxsflash *b47s = mtd->priv;
  19 +       int written = 0;
  20 +
  21 +       /* Enable writes */
  22 +       bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
  23 +
  24 +       /* Write first byte */
  25 +       b47s->cc_write(b47s, BCMA_CC_FLASHADDR, offset);
  26 +       b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
  27 +
  28 +       /* Program page */
  29 +       if (b47s->bcma_cc->core->id.rev < 20) {
  30 +               bcm47xxsflash_cmd(b47s, OPCODE_ST_PP);
  31 +               return 1; /* 1B written */
  32 +       }
  33 +
  34 +       /* Program page and set CSA (on newer chips we can continue writing) */
  35 +       bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | OPCODE_ST_PP);
  36 +       offset++;
  37 +       len--;
  38 +       written++;
  39 +
  40 +       while (len > 0) {
  41 +               /* Page boundary, another function call is needed */
  42 +               if ((offset & 0xFF) == 0)
  43 +                       break;
  44 +
  45 +               bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | *buf++);
  46 +               offset++;
  47 +               len--;
  48 +               written++;
  49 +       }
  50 +
  51 +       /* All done, drop CSA & poll */
  52 +       b47s->cc_write(b47s, BCMA_CC_FLASHCTL, 0);
  53 +       udelay(1);
  54 +       if (bcm47xxsflash_poll(b47s, HZ / 10))
  55 +               pr_err("Flash rejected dropping CSA\n");
  56 +
  57 +       return written;
  58 +}
  59 +
  60 +static int bcm47xxsflash_write_at(struct mtd_info *mtd, u32 offset, size_t len,
  61 +                                 const u_char *buf)
  62 +{
  63 +       struct bcm47xxsflash *b47s = mtd->priv;
  64 +       u32 mask = b47s->blocksize - 1;
  65 +       u32 page = (offset & ~mask) << 1;
  66 +       u32 byte = offset & mask;
  67 +       int written = 0;
  68 +
  69 +       /* If we don't overwrite whole page, read it to the buffer first */
  70 +       if (byte || (len < b47s->blocksize)) {
  71 +               int err;
  72 +
  73 +               b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
  74 +               bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_LOAD);
  75 +               /* 250 us for AT45DB321B */
  76 +               err = bcm47xxsflash_poll(b47s, HZ / 1000);
  77 +               if (err) {
  78 +                       pr_err("Timeout reading page 0x%X info buffer\n", page);
  79 +                       return err;
  80 +               }
  81 +       }
  82 +
  83 +       /* Change buffer content with our data */
  84 +       while (len > 0) {
  85 +               /* Page boundary, another function call is needed */
  86 +               if (byte == b47s->blocksize)
  87 +                       break;
  88 +
  89 +               b47s->cc_write(b47s, BCMA_CC_FLASHADDR, byte++);
  90 +               b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
  91 +               bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_WRITE);
  92 +               len--;
  93 +               written++;
  94 +       }
  95 +
  96 +       /* Program page with the buffer content */
  97 +       b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
  98 +       bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_PROGRAM);
  99 +
 100 +       return written;
 101 +}
 102 +
 103 +static int bcm47xxsflash_write(struct mtd_info *mtd, loff_t to, size_t len,
 104 +                              size_t *retlen, const u_char *buf)
 105 +{
 106 +       struct bcm47xxsflash *b47s = mtd->priv;
 107 +       int written;
 108 +
 109 +       /* Writing functions can return without writing all passed data, for
 110 +        * example when the hardware is too old or when we git page boundary.
 111 +        */
 112 +       while (len > 0) {
 113 +               switch (b47s->type) {
 114 +               case BCM47XXSFLASH_TYPE_ST:
 115 +                       written = bcm47xxsflash_write_st(mtd, to, len, buf);
 116 +                       break;
 117 +               case BCM47XXSFLASH_TYPE_ATMEL:
 118 +                       written = bcm47xxsflash_write_at(mtd, to, len, buf);
 119 +                       break;
 120 +               default:
 121 +                       BUG_ON(1);
 122 +               }
 123 +               if (written < 0) {
 124 +                       pr_err("Error writing at offset 0x%llX\n", to);
 125 +                       return written;
 126 +               }
 127 +               to += (loff_t)written;
 128 +               len -= written;
 129 +               *retlen += written;
 130 +               buf += written;
 131 +       }
 132 +
 133 +       return 0;
 134 +}
 135 +
 136  static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s)
 137  {
 138         struct mtd_info *mtd = &b47s->mtd;
 139 @@ -123,16 +244,17 @@ static void bcm47xxsflash_fill_mtd(struc
 140         mtd->priv = b47s;
 141         mtd->name = "bcm47xxsflash";
 142         mtd->owner = THIS_MODULE;
 143 -       mtd->type = MTD_ROM;
 144
 145 -       /* TODO: implement writing support and verify/change following code */
 146 -       mtd->flags = MTD_CAP_ROM;
 147 +       mtd->type = MTD_NORFLASH;
 148 +       mtd->flags = MTD_CAP_NORFLASH;
 149         mtd->size = b47s->size;
 150         mtd->erasesize = b47s->blocksize;
 151 -       mtd->writebufsize = mtd->writesize = 1;
 152 +       mtd->writesize = 1;
 153 +       mtd->writebufsize = 1;
 154
 155         mtd->_erase = bcm47xxsflash_erase;
 156         mtd->_read = bcm47xxsflash_read;
 157 +       mtd->_write = bcm47xxsflash_write;
 158  }
 159
 160  /**************************************************