target/linux/brcm2708/patches-4.4/0136-bcm2835-sdhost-Add-workaround-for-odd-behaviour-on-s.patch

   1 From 205e27a7f94a5531764cc517ce43623361ca466c Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Tue, 19 Jan 2016 17:16:38 +0000
   4 Subject: [PATCH 136/170] bcm2835-sdhost: Add workaround for odd behaviour on
   5  some cards
   6
   7 For reasons not understood, the sdhost driver fails when reading
   8 sectors very near the end of some SD cards. The problem could
   9 be related to the similar issue that reading the final sector
  10 of any card as part of a multiple read never completes, and the
  11 workaround is an extension of the mechanism introduced to solve
  12 that problem which ensures those sectors are always read singly.
  13 ---
  14  drivers/mmc/host/bcm2835-sdhost.c | 61 +++++++++++++++++++++++++++++++++------
  15  1 file changed, 52 insertions(+), 9 deletions(-)
  16
  17 --- a/drivers/mmc/host/bcm2835-sdhost.c
  18 +++ b/drivers/mmc/host/bcm2835-sdhost.c
  19 @@ -173,6 +173,9 @@ struct bcm2835_host {
  20         u32                             overclock_50;   /* frequency to use when 50MHz is requested (in MHz) */
  21         u32                             overclock;      /* Current frequency if overclocked, else zero */
  22         u32                             pio_limit;      /* Maximum block count for PIO (0 = always DMA) */
  23 +
  24 +       u32                             sectors;        /* Cached card size in sectors */
  25 +       u32                             single_read_sectors[8];
  26  };
  27
  28
  29 @@ -277,6 +280,9 @@ static void bcm2835_sdhost_reset_interna
  30  {
  31         u32 temp;
  32
  33 +       if (host->debug)
  34 +               pr_info("%s: reset\n", mmc_hostname(host->mmc));
  35 +
  36         bcm2835_sdhost_set_power(host, false);
  37
  38         bcm2835_sdhost_write(host, 0, SDCMD);
  39 @@ -299,6 +305,8 @@ static void bcm2835_sdhost_reset_interna
  40         bcm2835_sdhost_set_power(host, true);
  41         mdelay(10);
  42         host->clock = 0;
  43 +       host->sectors = 0;
  44 +       host->single_read_sectors[0] = ~0;
  45         bcm2835_sdhost_write(host, host->hcfg, SDHCFG);
  46         bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
  47         mmiowb();
  48 @@ -309,8 +317,6 @@ static void bcm2835_sdhost_reset(struct
  49  {
  50         struct bcm2835_host *host = mmc_priv(mmc);
  51         unsigned long flags;
  52 -       if (host->debug)
  53 -               pr_info("%s: reset\n", mmc_hostname(mmc));
  54         spin_lock_irqsave(&host->lock, flags);
  55
  56         bcm2835_sdhost_reset_internal(host);
  57 @@ -676,6 +682,32 @@ static void bcm2835_sdhost_prepare_data(
  58         host->flush_fifo = 0;
  59         host->data->bytes_xfered = 0;
  60
  61 +       if (!host->sectors && host->mmc->card)
  62 +       {
  63 +               struct mmc_card *card = host->mmc->card;
  64 +               if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) {
  65 +                       /*
  66 +                        * The EXT_CSD sector count is in number of 512 byte
  67 +                        * sectors.
  68 +                        */
  69 +                       host->sectors = card->ext_csd.sectors;
  70 +                       pr_err("%s: using ext_csd!\n", mmc_hostname(host->mmc));
  71 +               } else {
  72 +                       /*
  73 +                        * The CSD capacity field is in units of read_blkbits.
  74 +                        * set_capacity takes units of 512 bytes.
  75 +                        */
  76 +                       host->sectors = card->csd.capacity <<
  77 +                               (card->csd.read_blkbits - 9);
  78 +               }
  79 +               host->single_read_sectors[0] = host->sectors - 65;
  80 +               host->single_read_sectors[1] = host->sectors - 64;
  81 +               host->single_read_sectors[2] = host->sectors - 33;
  82 +               host->single_read_sectors[3] = host->sectors - 32;
  83 +               host->single_read_sectors[4] = host->sectors - 1;
  84 +               host->single_read_sectors[5] = ~0; /* Safety net */
  85 +       }
  86 +
  87         host->use_dma = host->have_dma && (data->blocks > host->pio_limit);
  88         if (!host->use_dma) {
  89                 int flags;
  90 @@ -1246,6 +1278,10 @@ static u32 bcm2835_sdhost_block_irq(stru
  91
  92                         bcm2835_sdhost_finish_data(host);
  93                 } else {
  94 +                       /* Reset the timer */
  95 +                       mod_timer(&host->pio_timer,
  96 +                                 jiffies + host->pio_timeout);
  97 +
  98                         bcm2835_sdhost_transfer_pio(host);
  99
 100                         /* Reset the timer */
 101 @@ -1450,8 +1486,8 @@ void bcm2835_sdhost_set_clock(struct bcm
 102         host->cdiv = div;
 103         bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
 104
 105 -       /* Set the timeout to 500ms */
 106 -       bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
 107 +       /* Set the timeout to 250ms */
 108 +       bcm2835_sdhost_write(host, host->mmc->actual_clock/4, SDTOUT);
 109
 110         if (host->debug)
 111                 pr_info("%s: clock=%d -> max_clk=%d, cdiv=%x (actual clock %d)\n",
 112 @@ -1566,13 +1602,20 @@ static int bcm2835_sdhost_multi_io_quirk
 113            reading the final sector of the card as part of a multiple read
 114            problematic. Detect that case and shorten the read accordingly.
 115         */
 116 -       /* csd.capacity is in weird units - convert to sectors */
 117 -       u32 card_sectors = (card->csd.capacity << (card->csd.read_blkbits - 9));
 118 +       struct bcm2835_host *host;
 119 +
 120 +       host = mmc_priv(card->host);
 121
 122 -       if ((direction == MMC_DATA_READ) &&
 123 -           ((blk_pos + blk_size) == card_sectors))
 124 -               blk_size--;
 125 +       if (direction == MMC_DATA_READ)
 126 +       {
 127 +               int i;
 128 +               int sector;
 129 +               for (i = 0; blk_pos > (sector = host->single_read_sectors[i]); i++)
 130 +                       continue;
 131
 132 +               if ((blk_pos + blk_size) > sector)
 133 +                       blk_size = (blk_pos == sector) ? 1 : (sector - blk_pos);
 134 +       }
 135         return blk_size;
 136  }
 137