[PATCH v3 1/4] mmc: sdhci: fix interrupt storm from card detection
From: Shawn Guo <hidden>
Date: 2011-06-20 10:38:42
Also in:
linux-mmc
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, secure digital host controller interface (sdhci) driver, the rest · Maintainers:
Ulf Hansson, Adrian Hunter, Linus Torvalds
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 <redacted> Cc: Eric Benard <redacted> --- drivers/mmc/host/sdhci.c | 27 +++++++++++++++++++++++---- 1 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 91d9892..d94e2b4 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c@@ -127,7 +127,9 @@ 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 = sdhci_readl(host, SDHCI_PRESENT_STATE) & + SDHCI_CARD_PRESENT; + u32 irqs = present ? SDHCI_INT_CARD_REMOVE : SDHCI_INT_CARD_INSERT; if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION) return;
@@ -2154,13 +2156,30 @@ 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); + 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);
--
1.7.4.1