On Mon, Nov 1, 2010 at 10:27 AM, Ohad Ben-Cohen <ohad@xxxxxxxxxx> wrote: > On Sun, Oct 31, 2010 at 9:06 PM, Ohad Ben-Cohen <ohad@xxxxxxxxxx> wrote: > ... >> we need to support boards with controllers/cards >> which we can't power off in runtime. >> >> On such boards, the right thing to do would be to disable runtime PM altogether. > > The patch below (/attached) should trivially fix the problem - can you > please check it out ? > > It's very simple: it just requires hosts to explicitly indicate they > support runtime powering off/on their cards (by means of > MMC_CAP_RUNTIME_PM). > > There is no way around this I'm afraid: it is legitimate for a > board/host/card configuration not to support powering off the card > after boot, and we must allow it. > > In addition having an explicit MMC_CAP_RUNTIME_PM will also allow us > smoother transition to runtime PM behavior. Developers will have to > explicitly turn it on, and will not be surprised if things won't > immediately work. > > Please note that this cap is not interchangeable, and can't be replace > with CONFIG_PM_RUNTIME. > > Having said that, I still think we need to understand why CMD3 timed > out on the XO-1.5. Just to update the list, the problem with the XO-1.5 was because the sd8686 has an external reset gpio line which is currently being manipulated manually by an out-of-tree kernel patch: http://dev.laptop.org/git/olpc-2.6/commit/?h=olpc-2.6.35&id=e9bee721fb0cc303286d1fe5df4930ce79b0b1e0 ... which makes me wonder whether we really want to take that MMC_CAP_RUNTIME_PM road. I'm not sure anymore. We need a demonstrated hardware limitation before we take that approach (or a setup which worked using vanilla kernels and now doesn't), because frankly this MMC_CAP_RUNTIME_PM approach is cumbersome and involving. I would not like to introduce it just to fix out-of-tree software issues, and it seems that at least the XO-1.5 case can be cleanly solved by software (e.g. by letting the regulator handle that sd8686 quirk). I'm looping in Arnd, who reported similar problems with b43-sdio on AP4EVB (arm) with tmio_mmc. Arnd, We're trying to exactly understand the reasons behind the reported SDIO runtime pm failures (we had two, yours, and OLPC). So far it seems that the OLPC had a software issue, and I'm wondering about yours. Can you please supply additional information about your board ? where does your wifi card gets its power from ? is there an external gpio involved ? Were you able to work with vanilla kernels (prior to 2.6.37) or do you carry some out-of-tree patches ? Thanks, Ohad. > > From 6b5691bdd8184cc0876d209c69d38844ea10f678 Mon Sep 17 00:00:00 2001 > From: Ohad Ben-Cohen <ohad@xxxxxxxxxx> > Date: Mon, 1 Nov 2010 09:41:44 +0200 > Subject: [PATCH] mmc: add MMC_CAP_RUNTIME_PM > > Some board/card/host configurations are not capable of powering off/on > on the card during runtime. > > To support such configurations, and to allow smoother transition to > runtime PM behavior, MMC_CAP_RUNTIME_PM is added, so hosts need to > explicitly indicate that it's OK to power off their cards after boot. > > This will prevent sdio_bus_probe() from failing to power on the card > when the driver is loaded on such setups. > > Signed-off-by: Ohad Ben-Cohen <ohad@xxxxxxxxxx> > --- > drivers/mmc/core/sdio.c | 37 +++++++++++++++++++++++-------------- > drivers/mmc/core/sdio_bus.c | 33 ++++++++++++++++++++++----------- > include/linux/mmc/host.h | 1 + > 3 files changed, 46 insertions(+), 25 deletions(-) > > diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c > index 6a9ad40..373d56d 100644 > --- a/drivers/mmc/core/sdio.c > +++ b/drivers/mmc/core/sdio.c > @@ -547,9 +547,11 @@ static void mmc_sdio_detect(struct mmc_host *host) > BUG_ON(!host->card); > > /* Make sure card is powered before detecting it */ > - err = pm_runtime_get_sync(&host->card->dev); > - if (err < 0) > - goto out; > + if (host->caps & MMC_CAP_RUNTIME_PM) { > + err = pm_runtime_get_sync(&host->card->dev); > + if (err < 0) > + goto out; > + } > > mmc_claim_host(host); > > @@ -570,7 +572,8 @@ out: > } > > /* Tell PM core that we're done */ > - pm_runtime_put(&host->card->dev); > + if (host->caps & MMC_CAP_RUNTIME_PM) > + pm_runtime_put(&host->card->dev); > } > > /* > @@ -720,16 +723,21 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr) > card = host->card; > > /* > - * Let runtime PM core know our card is active > + * Enable runtime PM only if supported by host+card+board > */ > - err = pm_runtime_set_active(&card->dev); > - if (err) > - goto remove; > + if (host->caps & MMC_CAP_RUNTIME_PM) { > + /* > + * Let runtime PM core know our card is active > + */ > + err = pm_runtime_set_active(&card->dev); > + if (err) > + goto remove; > > - /* > - * Enable runtime PM for this card > - */ > - pm_runtime_enable(&card->dev); > + /* > + * Enable runtime PM for this card > + */ > + pm_runtime_enable(&card->dev); > + } > > /* > * The number of functions on the card is encoded inside > @@ -747,9 +755,10 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr) > goto remove; > > /* > - * Enable Runtime PM for this func > + * Enable Runtime PM for this func (if supported) > */ > - pm_runtime_enable(&card->sdio_func[i]->dev); > + if (host->caps & MMC_CAP_RUNTIME_PM) > + pm_runtime_enable(&card->sdio_func[i]->dev); > } > > mmc_release_host(host); > diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c > index 2716c7a..f3ce21b 100644 > --- a/drivers/mmc/core/sdio_bus.c > +++ b/drivers/mmc/core/sdio_bus.c > @@ -17,6 +17,7 @@ > #include <linux/pm_runtime.h> > > #include <linux/mmc/card.h> > +#include <linux/mmc/host.h> > #include <linux/mmc/sdio_func.h> > > #include "sdio_cis.h" > @@ -132,9 +133,11 @@ static int sdio_bus_probe(struct device *dev) > * it should call pm_runtime_put_noidle() in its probe routine and > * pm_runtime_get_noresume() in its remove routine. > */ > - ret = pm_runtime_get_sync(dev); > - if (ret < 0) > - goto out; > + if (func->card->host->caps & MMC_CAP_RUNTIME_PM) { > + ret = pm_runtime_get_sync(dev); > + if (ret < 0) > + goto out; > + } > > /* Set the default block size so the driver is sure it's something > * sensible. */ > @@ -151,7 +154,8 @@ static int sdio_bus_probe(struct device *dev) > return 0; > > disable_runtimepm: > - pm_runtime_put_noidle(dev); > + if (func->card->host->caps & MMC_CAP_RUNTIME_PM) > + pm_runtime_put_noidle(dev); > out: > return ret; > } > @@ -160,12 +164,14 @@ static int sdio_bus_remove(struct device *dev) > { > struct sdio_driver *drv = to_sdio_driver(dev->driver); > struct sdio_func *func = dev_to_sdio_func(dev); > - int ret; > + int ret = 0; > > /* Make sure card is powered before invoking ->remove() */ > - ret = pm_runtime_get_sync(dev); > - if (ret < 0) > - goto out; > + if (func->card->host->caps & MMC_CAP_RUNTIME_PM) { > + ret = pm_runtime_get_sync(dev); > + if (ret < 0) > + goto out; > + } > > drv->remove(func); > > @@ -178,10 +184,12 @@ static int sdio_bus_remove(struct device *dev) > } > > /* First, undo the increment made directly above */ > - pm_runtime_put_noidle(dev); > + if (func->card->host->caps & MMC_CAP_RUNTIME_PM) > + pm_runtime_put_noidle(dev); > > /* Then undo the runtime PM settings in sdio_bus_probe() */ > - pm_runtime_put_noidle(dev); > + if (func->card->host->caps & MMC_CAP_RUNTIME_PM) > + pm_runtime_put_noidle(dev); > > out: > return ret; > @@ -191,6 +199,8 @@ out: > > static int sdio_bus_pm_prepare(struct device *dev) > { > + struct sdio_func *func = dev_to_sdio_func(dev); > + > /* > * Resume an SDIO device which was suspended at run time at this > * point, in order to allow standard SDIO suspend/resume paths > @@ -212,7 +222,8 @@ static int sdio_bus_pm_prepare(struct device *dev) > * since there is little point in failing system suspend if a > * device can't be resumed. > */ > - pm_runtime_resume(dev); > + if (func->card->host->caps & MMC_CAP_RUNTIME_PM) > + pm_runtime_resume(dev); > > return 0; > } > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index c3ffad8..e5eee0e 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -167,6 +167,7 @@ struct mmc_host { > /* DDR mode at 1.8V */ > #define MMC_CAP_1_2V_DDR (1 << 12) /* can support */ > /* DDR mode at 1.2V */ > +#define MMC_CAP_RUNTIME_PM (1 << 13) /* Can power off/on in runtime */ > > mmc_pm_flag_t pm_caps; /* supported pm features */ > > -- > 1.7.0.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
