Re: [PATCH] mmc: dw_mmc: fix bug that cause 'Timeout sending command'

[Addy]

On 2015.02.09 12:51, Ulf Hansson wrote:
> On 5 February 2015 at 12:13, Addy Ke <addy.ke@xxxxxxxxxxxxxx> wrote:
> > Because of some uncertain factors, such as worse card or worse hardware,
> > DAT[3:0](the data lines) may be pulled down by card, and mmc controller
> > will be in busy state. This should not happend when mmc controller
> > send command to update card clocks. If this happends, mci_send_cmd will
> > be failed and we will get 'Timeout sending command', and then system will
> > be blocked. To avoid this, we need reset mmc controller.
> >
> > Signed-off-by: Addy Ke <addy.ke@xxxxxxxxxxxxxx>
>
> Hi Addy,
>
> Should I consider $subject patch as a better option to the one below?
No:
This patch fix the bug, which can be found by script:
    cd /sys/bus/platform/drivers/dwmmc_rockchip
    for i in $(seq 1 10000); do
      echo "========================" $i
      echo ff0c0000.dwmmc > unbind
      sleep .5
      echo ff0c0000.dwmmc > bind
      sleep 2
    done

> [PATCH] mmc: dw_mmc: rockchip: Add DW_MCI_QUIRK_RETRY_DELAY
This patch is for tuning issue: we should delay until card go to idle 
state, when the previous command return error.
> https://lkml.org/lkml/2015/1/13/562
>
> Kind regards
> Uffe
>
>
> > ---
> >   drivers/mmc/host/dw_mmc.c | 23 +++++++++++++++++++++++
> >   1 file changed, 23 insertions(+)
> >
> > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> > index 4d2e3c2..b1d6dfb 100644
> > --- a/drivers/mmc/host/dw_mmc.c
> > +++ b/drivers/mmc/host/dw_mmc.c
> > @@ -100,6 +100,7 @@ struct idmac_desc {
> >   };
> >   #endif /* CONFIG_MMC_DW_IDMAC */
> >
> > +static int dw_mci_card_busy(struct mmc_host *mmc);
> >   static bool dw_mci_reset(struct dw_mci *host);
> >   static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
> >
> > @@ -888,6 +889,26 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg)
> >                  cmd, arg, cmd_status);
> >   }
> >
> > +static void dw_mci_wait_busy(struct dw_mci_slot *slot)
> > +{
> > +       struct dw_mci *host = slot->host;
> > +       unsigned long timeout = jiffies + msecs_to_jiffies(500);
> > +
> > +       while (time_before(jiffies, timeout)) {
> > +               if (!dw_mci_card_busy(slot->mmc))
> > +                       return;
> > +       }
> > +       dev_err(host->dev, "Data busy (status %#x)\n",
> > +               mci_readl(slot->host, STATUS));
> > +
> > +       /*
> > +        * Data busy, this should not happend when mmc controller send command
> > +        * to update card clocks in non-volt-switch state. If it happends, we
> > +        * should reset controller to avoid getting "Timeout sending command".
> > +        */
> > +       dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS);
> > +}
> > +
> >   static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
> >   {
> >          struct dw_mci *host = slot->host;
> > @@ -899,6 +920,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
> >          /* We must continue to set bit 28 in CMD until the change is complete */
> >          if (host->state == STATE_WAITING_CMD11_DONE)
> >                  sdmmc_cmd_bits |= SDMMC_CMD_VOLT_SWITCH;
> > +       else
> > +               dw_mci_wait_busy(slot);
> >
> >          if (!clock) {
> >                  mci_writel(host, CLKENA, 0);
> > --
> > 1.8.3.2
> >
> >
> > --
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