On 4 May 2011 19:34, Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> wrote:
> On Wed, 4 May 2011, Per Forlin wrote:
>
>> 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.
>>
>> Signed-off-by: Per Forlin <per.forlin@xxxxxxxxxx>
>> Acked-by: Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx>
>> ---
>> drivers/mmc/core/sdio_irq.c | 30 ++++++++++++++++++++++++++++++
>> include/linux/mmc/card.h | 1 +
>> 2 files changed, 31 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
>> index b300161..64c4409 100644
>> --- 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);
>
> I think there is little point using a func variable here, especially
> since you already reference the handler pointer in the if() statement.
> Hence:
>
> if (card->sdio_single_irq && card->sdio_single_irq->irq_handler) {
> card->sdio_single_irq->irq_handler();
> return 1;
> }
>
What do you think about:
+ struct sdio_func *func = card->sdio_single_irq;
+
+ /*
+ * Optimization, if there is only 1 function interrupt registered
+ * call irq handler directly
+ */
+ if (func) {
+ func->irq_handler(func);
+ return 1;
+ }
- struct sdio_func *func = card->sdio_func[i - 1];
+ func = card->sdio_func[i - 1];
>> @@ -186,6 +196,24 @@ static int sdio_card_irq_put(struct mmc_card *card)
>> return 0;
>> }
>>
>> +/* If there is only 1 function registered set sdio_single_irq */
>> +static void sdio_single_irq_set(struct mmc_card *card)
>> +{
>
> The comment is slightly wrong. This should say "only 1 function
> interrupt registered..." Nothing prevents this from working with
> multiple functions if only one of them has claimed an interrupt.
>
> Other than that:
>
> Reviewed-by: Nicolas Pitre <nicolas.pitre@xxxxxxxxxx>
>
>
> Nicolas
>
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