2011-05-11 17:19:49

by Per Forlin

Subject: [PATCH v4] sdio: optimized SDIO IRQ handling for single irq

Optimize performance for single irq

Changes since v2.
* Rebase on mmc-next, change of line numbers no code changes.

Stefan Nilsson XK (1):
sdio: optimized SDIO IRQ handling for single irq

drivers/mmc/core/sdio_irq.c | 33 ++++++++++++++++++++++++++++++++-
include/linux/mmc/card.h | 1 +
2 files changed, 33 insertions(+), 1 deletions(-)

--
1.7.4.1

2011-05-11 16:56:28

by Per Forlin

Subject: [PATCH v4] sdio: optimized SDIO IRQ handling for single irq

From: Stefan Nilsson XK <[email protected]>

If there is only 1 function interrupt 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 <[email protected]>
Acked-by: Ulf Hansson <[email protected]>
Reviewed-by: Nicolas Pitre <[email protected]>
---
drivers/mmc/core/sdio_irq.c | 33 ++++++++++++++++++++++++++++++++-
include/linux/mmc/card.h | 1 +
2 files changed, 33 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
index b300161..03ead02 100644
--- a/drivers/mmc/core/sdio_irq.c
+++ b/drivers/mmc/core/sdio_irq.c
@@ -31,6 +31,17 @@ static int process_sdio_pending_irqs(struct mmc_card *card)
{
int i, ret, count;
unsigned char pending;
+ struct sdio_func *func;
+
+ /*
+ * Optimization, if there is only 1 function interrupt registered
+ * call irq handler directly
+ */
+ func = card->sdio_single_irq;
+ if (func) {
+ func->irq_handler(func);
+ return 1;
+ }

ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
if (ret) {
@@ -42,7 +53,7 @@ static int process_sdio_pending_irqs(struct mmc_card *card)
count = 0;
for (i = 1; i <= 7; i++) {
if (pending & (1 << i)) {
- struct sdio_func *func = card->sdio_func[i - 1];
+ func = card->sdio_func[i - 1];
if (!func) {
printk(KERN_WARNING "%s: pending IRQ for "
"non-existent function\n",
@@ -186,6 +197,24 @@ 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)
+{
+ struct sdio_func *func;
+ int i;
+
+ card->sdio_single_irq = NULL;
+ if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
+ card->host->sdio_irqs == 1)
+ for (i = 0; i < card->sdio_funcs; i++) {
+ func = card->sdio_func[i];
+ if (func && func->irq_handler) {
+ card->sdio_single_irq = func;
+ break;
+ }
+ }
+}
+
/**
* sdio_claim_irq - claim the IRQ for a SDIO function
* @func: SDIO function
@@ -227,6 +256,7 @@ int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
ret = sdio_card_irq_get(func->card);
if (ret)
func->irq_handler = NULL;
+ sdio_single_irq_set(func->card);

return ret;
}
@@ -251,6 +281,7 @@ int sdio_release_irq(struct sdio_func *func)
if (func->irq_handler) {
func->irq_handler = NULL;
sdio_card_irq_put(func->card);
+ sdio_single_irq_set(func->card);
}

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 d8dffc9..4910dec 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -191,6 +191,7 @@ 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 */
--
1.7.4.1

2011-05-11 16:45:16

by Chris Ball

Subject: Re: [PATCH v4] sdio: optimized SDIO IRQ handling for single irq

Hi Per,

On Wed, May 11 2011, Per Forlin wrote:
> Optimize performance for single irq
>
> Changes since v2.
> * Rebase on mmc-next, change of line numbers no code changes.
>
> Stefan Nilsson XK (1):
> sdio: optimized SDIO IRQ handling for single irq
>
> drivers/mmc/core/sdio_irq.c | 33 ++++++++++++++++++++++++++++++++-
> include/linux/mmc/card.h | 1 +
> 2 files changed, 33 insertions(+), 1 deletions(-)

Odd, still doesn't apply here:

error: patch failed: drivers/mmc/core/sdio_irq.c:42
error: drivers/mmc/core/sdio_irq.c: patch does not apply

patch -p1 says:
Hunk #2 succeeded at 53 with fuzz 1.

So this still isn't rebased onto mmc-next properly. There haven't been
any changes to drivers/mmc/core/sdio_irq.c since 2008, though, so now
I'm wondering where you got the fuzz from..

- Chris.
--
Chris Ball <[email protected]> <http://printf.net/>
One Laptop Per Child