On Jun 21, 2011, at 9:40 PM, Shawn Guo wrote:
> On Tue, Jun 21, 2011 at 09:05:25AM -0700, Philip Rakity wrote:
>>
>> 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 <[email protected]>
>>> Cc: Eric Benard <[email protected]>
>>> Tested-by: Arnaud Patard <[email protected]>
>>> ---
>>> 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
>>
>
> I actually rewrote the body of the if-statement, and fixed one
> indentation in that specific line.
understand -- I'm happy with the results !
Philip
>
>>> + 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 <[email protected]>
>>
>
> --
> Regards,
> Shawn
>
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