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: Shawn Guo <shawn.guo@linaro.org>
Cc: Eric Benard <eric@eukrea.com>
Tested-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 58d5436..aa25eae 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -127,11 +127,15 @@
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 @@
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);
+ 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);