[PATCH v2 4/4] mmc: dw_mmc: Do not wait for DTO in case of error

[Mårten Lindahl]

When running the ARTPEC-8 DWMMC IP version, and a data error interrupt
comes during a data read transfer, there is no guarantee for the data
transfer over interrupt (DTO) to come within the specified data timeout.
This case is handled by the dto_timer handler which will complete the
request with the comment:

 /*
  * If DTO interrupt does NOT come in sending data state,
  * we should notify the driver to terminate current transfer
  * and report a data timeout to the core.
  */

But since the ARTPEC-8 DWMMC IP version, supports an extended TMOUT
register which allows longer timeouts than the non ARTPEC-8 version
does, waiting for the dto_timer to complete the request in error cases
may cause the request to take significantly longer time than necessary.
This is specifically true for the failing steps during tuning of a
device.

Fix this by completing the request when the error interrupt comes.

Signed-off-by: Mårten Lindahl <marten.lindahl at axis.com>
---
 drivers/mmc/host/dw_mmc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 45ea9fd97a6a..d6b76f47b1a2 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2777,11 +2777,19 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
 		if (pending & DW_MCI_DATA_ERROR_FLAGS) {
 			spin_lock(&host->irq_lock);
 
+			if (host->quirks & DW_MMC_QUIRK_EXTENDED_TMOUT)
+				del_timer(&host->dto_timer);
+
 			/* if there is an error report DATA_ERROR */
 			mci_writel(host, RINTSTS, DW_MCI_DATA_ERROR_FLAGS);
 			host->data_status = pending;
 			smp_wmb(); /* drain writebuffer */
 			set_bit(EVENT_DATA_ERROR, &host->pending_events);
+
+			if (host->quirks & DW_MMC_QUIRK_EXTENDED_TMOUT)
+				/* In case of error, we cannot expect a DTO */
+				set_bit(EVENT_DATA_COMPLETE, &host->pending_events);
+
 			tasklet_schedule(&host->tasklet);
 
 			spin_unlock(&host->irq_lock);
-- 
2.20.1