| Message ID | 1304525161-14448-2-git-send-email-per.forlin@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2011/5/4 Per Forlin <per.forlin@linaro.org>: > From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> > > 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 in sdio_claim_irq(): card->func->irq_handler = ... if (host->sdio_irqs == 1) card->sdio_irq_func = func; else card->sdio_irq_func = NULL; 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); in struct mmc_card: struct sdio_func *sdio_irq_func; Best Regards, Micha? Miros?aw -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2011/5/4 Micha? Miros?aw <mirqus@gmail.com>: > 2011/5/4 Per Forlin <per.forlin@linaro.org>: >> From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> >> >> 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, > Micha? Miros?aw > Thanks for your feedback, Per -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 4 May 2011, Per Forlin wrote: > From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> > > 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@linaro.org> > Acked-by: Ulf Hansson <ulf.hansson@stericsson.com> > --- > 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; } > @@ -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@linaro.org> Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 4 May 2011, Per Forlin wrote: > 2011/5/4 Micha? Miros?aw <mirqus@gmail.com>: > > 2011/5/4 Per Forlin <per.forlin@linaro.org>: > >> From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> > >> > >> 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? Yes because we want to be notified if the hardware returns pending interrupt flags for interrupts we didn't claim. > > 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? You cannot avoid checking MMC_CAP_SDIO_IRQ. If it isn't set the CCCr register must be polled in all cases. Nicolas
On 4 May 2011 19:34, Nicolas Pitre <nicolas.pitre@linaro.org> wrote: > On Wed, 4 May 2011, Per Forlin wrote: > >> From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> >> >> 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@linaro.org> >> Acked-by: Ulf Hansson <ulf.hansson@stericsson.com> >> --- >> 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@linaro.org> > > > Nicolas > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 4 May 2011, Per Forlin wrote: > On 4 May 2011 19:34, Nicolas Pitre <nicolas.pitre@linaro.org> wrote: > > On Wed, 4 May 2011, Per Forlin wrote: > > > >> From: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> > >> > >> 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@linaro.org> > >> Acked-by: Ulf Hansson <ulf.hansson@stericsson.com> > >> --- > >> 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; > + } Sure, but I'd move the assignment right before the if() in that case for clarity: 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; } [...] Nicolas
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); + 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", @@ -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) +{ + 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 +255,7 @@ 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 +280,7 @@ 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, ®); diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h index adb4888..0d64211 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 */