Commit d25928d1 authored by Shawn Guo's avatar Shawn Guo Committed by Chris Ball
Browse files

mmc: sdhci: fix interrupt storm from card detection 

The issue was initially found by Eric Benard as below.

http://permalink.gmane.org/gmane.linux.ports.arm.kernel/108031



Not sure about other SDHCI based controller, but on Freescale eSDHC,
the SDHCI_INT_CARD_INSERT bits will be immediately set again when it
gets cleared, if a card is inserted. The driver need to mask the irq
to prevent interrupt storm which will freeze the system.  And the
SDHCI_INT_CARD_REMOVE gets the same situation.

The patch fixes the problem based on the initial idea from
Eric Benard.

Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
Cc: Eric Benard <eric@eukrea.com>
Tested-by: default avatarArnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent e312eb1e

drivers/mmc/host/sdhci.c

+25 −4
Original line number Diff line number Diff line
@@ -127,11 +127,15 @@ static void sdhci_mask_irqs(struct sdhci_host *host, u32 irqs) 


static void sdhci_set_card_detection(struct sdhci_host *host, bool enable)

{

	u32 irqs = SDHCI_INT_CARD_REMOVE | SDHCI_INT_CARD_INSERT;

	u32 present, irqs;



	if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)

		return;



	present = sdhci_readl(host, SDHCI_PRESENT_STATE) &

			      SDHCI_CARD_PRESENT;

	irqs = present ? SDHCI_INT_CARD_REMOVE : SDHCI_INT_CARD_INSERT;



	if (enable)

		sdhci_unmask_irqs(host, irqs);

	else
@@ -2154,13 +2158,30 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) 
		mmc_hostname(host->mmc), intmask);



	if (intmask & (SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE)) {

		u32 present = sdhci_readl(host, SDHCI_PRESENT_STATE) &

			      SDHCI_CARD_PRESENT;



		/*

		 * There is a observation on i.mx esdhc.  INSERT bit will be

		 * immediately set again when it gets cleared, if a card is

		 * inserted.  We have to mask the irq to prevent interrupt

		 * storm which will freeze the system.  And the REMOVE gets

		 * the same situation.

		 *

		 * More testing are needed here to ensure it works for other

		 * platforms though.

		 */

		sdhci_mask_irqs(host, present ? SDHCI_INT_CARD_INSERT :

						SDHCI_INT_CARD_REMOVE);

		sdhci_unmask_irqs(host, present ? SDHCI_INT_CARD_REMOVE :

						  SDHCI_INT_CARD_INSERT);



		sdhci_writel(host, intmask & (SDHCI_INT_CARD_INSERT |

			     SDHCI_INT_CARD_REMOVE), SDHCI_INT_STATUS);

		intmask &= ~(SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE);

		tasklet_schedule(&host->card_tasklet);

	}



	intmask &= ~(SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE);



	if (intmask & SDHCI_INT_CMD_MASK) {

		sdhci_writel(host, intmask & SDHCI_INT_CMD_MASK,

			SDHCI_INT_STATUS);

CRA Git | Maintained and supported by SUSTech CRA and CCSE