On Jun 21, 2011, at 7:41 AM, Shawn Guo wrote:
> 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....@linaro.org>
> Cc: Eric Benard <e...@eukrea.com>
> Tested-by: Arnaud Patard <arnaud.pat...@rtp-net.org>
> ---
> drivers/mmc/host/sdhci.c | 29 +++++++++++++++++++++++++----
> 1 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 91d9892..790f959 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -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);
> + SDHCI_INT_CARD_REMOVE), SDHCI_INT_STATUS);
====
Please keep the old formatting since code does not change anything. Makes it
easier to find
the real change
> + 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
>
Reviewed-by: Philip Rakity <prak...@marvell.com>
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