mmc: dw_mmc: Add a timeout for sending CMD11

In the Designware databook's description of the "Voltage Switch Normal
Scenario" it instructs us to set a timer and fail the voltage change
if we don't see the voltage change interrupt within 2ms.  Let's
implement that.  Without implementing this I have often been able to
reproduce a hang while trying to send CMD11 on an rk3288-based board
while constantly ejecting and inserting UHS cards.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index f68ea4d..8e0836d 100644 (file)
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1021,6 +1021,15 @@ static void __dw_mci_start_request(struct dw_mci *host,
 
        dw_mci_start_command(host, cmd, cmdflags);
 
+       if (cmd->opcode == SD_SWITCH_VOLTAGE) {
+               /*
+                * Databook says to fail after 2ms w/ no response; give an
+                * extra jiffy just in case we're about to roll over.
+                */
+               mod_timer(&host->cmd11_timer,
+                         jiffies + msecs_to_jiffies(2) + 1);
+       }
+
        if (mrq->stop)
                host->stop_cmdr = dw_mci_prepare_command(slot->mmc, mrq->stop);
        else
@@ -2159,6 +2168,8 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
                /* Check volt switch first, since it can look like an error */
                if ((host->state == STATE_SENDING_CMD11) &&
                    (pending & SDMMC_INT_VOLT_SWITCH)) {
+                       del_timer(&host->cmd11_timer);
+
                        mci_writel(host, RINTSTS, SDMMC_INT_VOLT_SWITCH);
                        pending &= ~SDMMC_INT_VOLT_SWITCH;
                        dw_mci_cmd_interrupt(host, pending);
@@ -2572,6 +2583,18 @@ ciu_out:
        return ret;
 }
 
+static void dw_mci_cmd11_timer(unsigned long arg)
+{
+       struct dw_mci *host = (struct dw_mci *)arg;
+
+       if (host->state != STATE_SENDING_CMD11)
+               dev_info(host->dev, "Unexpected CMD11 timeout\n");
+
+       host->cmd_status = SDMMC_INT_RTO;
+       set_bit(EVENT_CMD_COMPLETE, &host->pending_events);
+       tasklet_schedule(&host->tasklet);
+}
+
 #ifdef CONFIG_OF
 static struct dw_mci_of_quirks {
        char *quirk;
@@ -2746,6 +2769,9 @@ int dw_mci_probe(struct dw_mci *host)
                }
        }
 
+       setup_timer(&host->cmd11_timer,
+                   dw_mci_cmd11_timer, (unsigned long)host);
+
        host->quirks = host->pdata->quirks;
 
        spin_lock_init(&host->lock);

diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index 471fb31..9efc567 100644 (file)
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -202,6 +202,8 @@ struct dw_mci {
        int                     irq;
 
        int                     sdio_id0;
+
+       struct timer_list       cmd11_timer;
 };
 
 /* DMA ops for Internal/External DMAC interface */