2011/5/4 Michał Mirosław <mirqus@xxxxxxxxx>:
> 2011/5/4 Per Forlin <per.forlin@xxxxxxxxxx>:
>> From: Stefan Nilsson XK <stefan.xk.nilsson@xxxxxxxxxxxxxx>
>>
>> If there is only 1 function registered it is possible to
>> improve performance by directly calling the irq handler
>> and avoiding the overhead of reading the CCCR registers.
>>
> [...]
>> --- a/drivers/mmc/core/sdio_irq.c
>> +++ b/drivers/mmc/core/sdio_irq.c
>> @@ -32,6 +32,16 @@ static int process_sdio_pending_irqs(struct mmc_card *card)
>> int i, ret, count;
>> unsigned char pending;
>>
>> + /*
>> + * Optimization, if there is only 1 function registered
>> + * call irq handler directly
>> + */
>> + if (card->sdio_single_irq && card->sdio_single_irq->irq_handler) {
>> + struct sdio_func *func = card->sdio_single_irq;
>> + func->irq_handler(func);
>> + return 1;
>> + }
> [...]
>
> The second condition can be avoided:
>
> in process_sdio_pending_irqs():
>
> if (card->sdio_irq_func)
> call handler and return
>
I added the second condition as a sanity check. Same check is used in
the main for loop
> ret = -EINVAL;
> } else if (func->irq_handler) {
> func->irq_handler(func);
Is the second check necessary here?
> in sdio_claim_irq():
>
> card->func->irq_handler = ...
> if (host->sdio_irqs == 1)
> card->sdio_irq_func = func;
> else
> card->sdio_irq_func = NULL;
I wanted to keep it simple and use same function in claim and release.
Your code looks nice.
Is if safe to not check the condition "(card->host->caps &
MMC_CAP_SDIO_IRQ)". What happens if the SDIO is in polling mode?
>
> in sdio_release_irq():
>
> card->sdio_irq_func = NULL;
> card->func->irq_handler = ...
> sdio_card_irq_put();
> if (host->sdio_irqs == 1)
> sdio_single_irq_set(func->card);
This works for me.
>
> in struct mmc_card:
> struct sdio_func *sdio_irq_func;
The name sdio_single_irq indicates it is only used for single irq.
"sdio_irq_func" is too generic I think. But the your name is shorter
and makes the indentation look nicer.
Not a big deal really.
I will wait until tomorrow to post patch v3. This will give time for
other to comment as well.
> Best Regards,
> Michał Mirosław
>
Thanks for your feedback,
Per
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