From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Stern Subject: Re: [RFC, PATCHv3 3/3] mmc: sdhci: handle wake-up from runtime_pm Date: Tue, 1 Mar 2011 14:53:46 -0500 (EST) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Pierre Tardy Cc: linux-pm@lists.linux-foundation.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org On Tue, 1 Mar 2011, Pierre Tardy wrote: > When sdhci is runtime_suspended, it can still receive a wake-up > because of card insertion. > The wake-up will then be signaled by an interrupt which cannot be serviced > immediatly, as the device is powered off, and register are not accessibles. > > We cannot call pm_runtime_get_sync() in irq context as on some architecture (e.g. intel_mid), > runtime_resume can lead to too much latency, due to e.g. PLL warm-up and such aggressive > power gating. > > We temporarly disable the interrupt, and trigger a runtime_resume of the device > The interrupt will be re-enabled when resume is finished. > > Signed-off-by: Pierre Tardy > --- > drivers/mmc/host/sdhci-pci.c | 8 +------- > drivers/mmc/host/sdhci.c | 30 +++++++++++++++++++++++++++++- > include/linux/mmc/sdhci.h | 2 ++ > scripts/checkpatch.pl | 6 +++--- > 4 files changed, 35 insertions(+), 11 deletions(-) > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 735c3f7..85a1956 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1599,6 +1599,21 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) > u32 intmask; > int cardint = 0; > > + /* we might come from a sd insertion or sdio irq wake.. */ > + if (pm_runtime_suspended()) { > + host->waking_up = 1; > + /* Note that we disable temporarly the interrupt until we do the > + * resume. If we don't then we'll get constantly interrupted > + * until we actually resume. > + * > + * as the irq is shared, this might not be very friendly to our > + * irq sharers but the pm_runtime workqueue should really be > + * called soon. Instead of disabling the IRQ, would it be possible to tell the device to stop generating an interrupt request? > + */ > + disable_irq_nosync(irq); > + pm_runtime_get(host->mmc->parent); Does this pm_runtime_get() have a corresponding pm_runtime_put()? I didn't notice one anywhere. > + return IRQ_NONE; > + } > spin_lock(&host->lock); > > intmask = sdhci_readl(host, SDHCI_INT_STATUS); > @@ -1747,7 +1762,12 @@ EXPORT_SYMBOL_GPL(sdhci_enable_irq_wakeups); > > int sdhci_runtime_suspend(struct sdhci_host *host) > { > - /* nothing to do yet */ > + u8 val; > + /* make sure we wake up on sdcard insert/remove enabled */ > + val = SDHCI_WAKE_ON_INSERT | SDHCI_WAKE_ON_REMOVE; > + if (host->mmc->pm_flags & MMC_PM_WAKE_SDIO_IRQ) > + val |= SDHCI_WAKE_ON_INT; > + sdhci_writeb(host, val, SDHCI_WAKE_UP_CONTROL); > return 0; > } > > @@ -1768,6 +1788,14 @@ int sdhci_runtime_resume(struct sdhci_host *host) > sdhci_set_ios(host->mmc, &host->mmc->ios); > mmiowb(); > > + if (host->waking_up) { > + host->waking_up = 0; > + /* Re-enable the irq now we are perfectly resumed. > + * Any yet unhandled interrupt (i.e. the wake) will retrigger > + * irq > + */ > + irq_enable(host->irq); > + } > return ret; > } > EXPORT_SYMBOL_GPL(sdhci_runtime_resume); > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl > index e3c7fc0..17aeda3 100755 > --- a/scripts/checkpatch.pl > +++ b/scripts/checkpatch.pl > @@ -1325,8 +1325,8 @@ sub process { > $prefix = "$filename:$realline: " if ($emacs && $file); > $prefix = "$filename:$linenr: " if ($emacs && !$file); > > - $here = "#$linenr: " if (!$file); > - $here = "#$realline: " if ($file); > + $here = "" if (!$file); > + $here = "" if ($file); > > # extract the filename as it passes > if ($line =~ /^diff --git.*?(\S+)$/) { > @@ -1349,7 +1349,7 @@ sub process { > next; > } > > - $here .= "FILE: $realfile:$realline:" if ($realcnt != 0); > + $here .= "$realfile:$realline:" if ($realcnt != 0); > > my $hereline = "$here\n$rawline\n"; > my $herecurr = "$here\n$rawline\n"; > Surely this doesn't belong in the patch. Alan Stern