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SubjectRe: [PATCH] sdio: optimized SDIO IRQ handling for single function
On Wed, 4 May 2011, Per Forlin wrote:

> On 4 May 2011 05:40, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> > On Tue, 3 May 2011, Per Forlin wrote:
> >
> >> From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.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@stericsson.com>
> >> Signed-off-by: Per Forlin <per.forlin@linaro.org>
> >
> > Acked-by: Nicolas Pitre <nicolas.pitre@linaro.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.

Yes, that's what I was about to propose after thinking about it some
more.

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

Something like this (untested) ?

diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
index b300161..4552727 100644
--- a/drivers/mmc/core/sdio_irq.c
+++ b/drivers/mmc/core/sdio_irq.c
@@ -32,6 +32,12 @@ static int process_sdio_pending_irqs(struct mmc_card *card)
int i, ret, count;
unsigned char pending;

+ if (card->sdio_single_irq) {
+ struct sdio_func *func = card->sdio_single_irq;
+ 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",
@@ -166,6 +172,7 @@ static int sdio_card_irq_get(struct mmc_card *card)
host->sdio_irqs--;
return err;
}
+ return 1;
}

return 0;
@@ -183,7 +190,7 @@ static int sdio_card_irq_put(struct mmc_card *card)
kthread_stop(host->sdio_irq_thread);
}

- return 0;
+ return (host->sdio_irqs == 1);
}

/**
@@ -225,8 +232,12 @@ int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)

func->irq_handler = handler;
ret = sdio_card_irq_get(func->card);
- if (ret)
+ if (ret < 0) {
func->irq_handler = NULL;
+ } else if (ret == 1) {
+ card->sdio_single_irq = func;
+ ret = 0;
+ }

return ret;
}
@@ -250,7 +261,17 @@ int sdio_release_irq(struct sdio_func *func)

if (func->irq_handler) {
func->irq_handler = NULL;
- sdio_card_irq_put(func->card);
+ if (sdio_card_irq_put(func->card) == 1) {
+ int i;
+ for (i = 0, i < 7; i++) {
+ if (func->card->sdio_func[i].irq_handler) {
+ func->card->sdio_single_irq =
+ func->card->sdio_func[i];
+ break;
+ }
+ }
+ } else
+ func->card->sdio_single_irq = NULL;
}

ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index adb4888..fee3df3 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -145,6 +145,7 @@ struct mmc_card {
struct sdio_cccr cccr; /* common card info */
struct sdio_cis cis; /* common tuple info */
struct sdio_func *sdio_func[SDIO_MAX_FUNCS]; /* SDIO functions (devices) */
+ struct sdio_func *sdio_single_irq; /* SDIO function when only one IRQ active */
unsigned num_info; /* number of info strings */
const char **info; /* info strings */
struct sdio_func_tuple *tuples; /* unknown common tuples */

Nicolas


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