target/linux/sunxi/patches-4.1/140-mmc-sdio-reliability-fix.patch

   1 From 8a7013f47196abed7e6a40e93d1de1639cd46228 Mon Sep 17 00:00:00 2001
   2 From: Hans de Goede <hdegoede@redhat.com>
   3 Date: Fri, 10 Jul 2015 17:03:03 +0200
   4 Subject: [PATCH] mmc: sunxi: Don't start commands while the card is busy
   5
   6 Some sdio wifi modules have not been working reliable with the sunxi-mmc
   7 host code. This turns out to be caused by it starting new commands while
   8 the card signals that it is still busy processing a previous command.
   9
  10 This commit fixes this, thereby fixing the wifi reliability issues on
  11 the Cubietruck and other sunxi boards using sdio wifi.
  12
  13 Reported-by: Eugene K <sigintmailru@gmail.com>
  14 Suggested-by: Eugene K <sigintmailru@gmail.com>
  15 Cc: Eugene K <sigintmailru@gmail.com>
  16 Cc: Arend van Spriel <arend@broadcom.com>
  17 Signed-off-by: Hans de Goede <hdegoede@redhat.com>
  18 ---
  19 Changes in v2:
  20 -Properly accredit Eugene K for coming up with the fix for this
  21 ---
  22  drivers/mmc/host/sunxi-mmc.c | 32 ++++++++++++++++++++++++++++++++
  23  1 file changed, 32 insertions(+)
  24
  25 --- a/drivers/mmc/host/sunxi-mmc.c
  26 +++ b/drivers/mmc/host/sunxi-mmc.c
  27 @@ -289,6 +289,24 @@ static int sunxi_mmc_init_host(struct mm
  28         return 0;
  29  }
  30
  31 +/* Wait for card to report ready before starting a new cmd */
  32 +static int sunxi_mmc_wait_card_ready(struct sunxi_mmc_host *host)
  33 +{
  34 +       unsigned long expire = jiffies + msecs_to_jiffies(500);
  35 +       u32 rval;
  36 +
  37 +       do {
  38 +               rval = mmc_readl(host, REG_STAS);
  39 +       } while (time_before(jiffies, expire) && (rval & SDXC_CARD_DATA_BUSY));
  40 +
  41 +       if (rval & SDXC_CARD_DATA_BUSY) {
  42 +               dev_err(mmc_dev(host->mmc), "Error R1 ready timeout\n");
  43 +               return -EIO;
  44 +       }
  45 +
  46 +       return 0;
  47 +}
  48 +
  49  static void sunxi_mmc_init_idma_des(struct sunxi_mmc_host *host,
  50                                     struct mmc_data *data)
  51  {
  52 @@ -383,6 +401,8 @@ static void sunxi_mmc_send_manual_stop(s
  53         u32 arg, cmd_val, ri;
  54         unsigned long expire = jiffies + msecs_to_jiffies(1000);
  55
  56 +       sunxi_mmc_wait_card_ready(host);
  57 +
  58         cmd_val = SDXC_START | SDXC_RESP_EXPIRE |
  59                   SDXC_STOP_ABORT_CMD | SDXC_CHECK_RESPONSE_CRC;
  60
  61 @@ -597,6 +617,11 @@ static int sunxi_mmc_oclk_onoff(struct s
  62  {
  63         unsigned long expire = jiffies + msecs_to_jiffies(250);
  64         u32 rval;
  65 +       int ret;
  66 +
  67 +       ret = sunxi_mmc_wait_card_ready(host);
  68 +       if (ret)
  69 +               return ret;
  70
  71         rval = mmc_readl(host, REG_CLKCR);
  72         rval &= ~(SDXC_CARD_CLOCK_ON | SDXC_LOW_POWER_ON);
  73 @@ -784,6 +809,13 @@ static void sunxi_mmc_request(struct mmc
  74                 mmc_request_done(mmc, mrq);
  75                 return;
  76         }
  77 +
  78 +       ret = sunxi_mmc_wait_card_ready(host);
  79 +       if (ret) {
  80 +               mrq->cmd->error = ret;
  81 +               mmc_request_done(mmc, mrq);
  82 +               return;
  83 +       }
  84
  85         if (data) {
  86                 ret = sunxi_mmc_map_dma(host, data);