linux-kernel - Re: [PATCH] sdio: optimized SDIO IRQ handling for single function

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Date:	Wed, 4 May 2011 10:36:11 +0200
From:	Per Forlin <per.forlin@...aro.org>
To:	Nicolas Pitre <nicolas.pitre@...aro.org>
Cc:	linux-mmc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	lkml <linux-kernel@...r.kernel.org>, linaro-dev@...ts.linaro.org,
	Stefan Nilsson XK <stefan.xk.nilsson@...ricsson.com>,
	Ulf HANSSON <ulf.hansson@...ricsson.com>
Subject: Re: [PATCH] sdio: optimized SDIO IRQ handling for single function

On 4 May 2011 05:40, Nicolas Pitre <nicolas.pitre@...aro.org> wrote:
> On Tue, 3 May 2011, Per Forlin wrote:
>
>> From: Stefan Nilsson XK <stefan.xk.nilsson@...ricsson.com>
>>
>> If there is only 1 function registered, and IRQ:s are supported and
>> currently enabled, call the callback handler directly
>> without checking the CCCR registers.
>>
>> Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@...ricsson.com>
>> Signed-off-by: Per Forlin <per.forlin@...aro.org>
>
> Acked-by: Nicolas Pitre <nicolas.pitre@...aro.org>
>
I am working o a patch version 2 after offline discussion with Ulf Hansson.
Instead of adding this code here.
Add sdio_single_func member in mmc_card. Set and reset this function
in sdio_claim_irq and sdio_release_irq.
process_sdio_pending_irqs would only check if sdio_single_func is !=
null and call it.

This will result in a bigger patch overall but the new code in
process_sdio_pending_irqs will be minimal.

>> ---
>>  drivers/mmc/core/sdio_irq.c |   14 ++++++++++++++
>>  1 files changed, 14 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
>> index b300161..25291bf 100644
>> --- a/drivers/mmc/core/sdio_irq.c
>> +++ b/drivers/mmc/core/sdio_irq.c
>> @@ -32,6 +32,20 @@ static int process_sdio_pending_irqs(struct mmc_card *card)
>>       int i, ret, count;
>>       unsigned char pending;
>>
>> +     /*
>> +      * If there is only 1 function registered
>> +      * call irq directly without checking the CCCR registers.
>> +      */
>> +     if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&

>> +         card->host->sdio_irqs && (card->sdio_funcs == 1))
>> +             for (i = 0; i < SDIO_MAX_FUNCS; i++) {
Minor adjustments.
card->sdio_funcs may be > 1 but still only one irq is registered.
No need to iterate more than "sdio_funcs" number of elements.
+ card->host->sdio_irqs == 1)
+             for (i = 0; i < card->sdio_funcs; i++) {

>> +                     struct sdio_func *func = card->sdio_func[i];
>> +                     if (func && func->irq_handler) {
>> +                             func->irq_handler(func);
>> +                             return 1;
>> +                     }
>> +             }
>> +
>>       ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
>>       if (ret) {
>>               printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
>> --
>> 1.7.4.1
>>
>>
>> _______________________________________________
>> linaro-dev mailing list
>> linaro-dev@...ts.linaro.org
>> http://lists.linaro.org/mailman/listinfo/linaro-dev
>>
>
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