* [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() @ 2012-08-18 8:10 Lothar Waßmann 2012-08-18 12:46 ` Shawn Guo 2012-09-18 23:07 ` Andrew Morton 0 siblings, 2 replies; 5+ messages in thread From: Lothar Waßmann @ 2012-08-18 8:10 UTC (permalink / raw) To: linux-arm-kernel If snvs_rtc_enable() happens to be descheduled for a period longer than the timout period, a timeout may be indicated even if the RTC status has changed meanwhile. Force a status read at the end of the timeout period to prevent bogus timeout errors. Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de> --- drivers/rtc/rtc-snvs.c | 22 +++++++++++++--------- 1 files changed, 13 insertions(+), 9 deletions(-) Compile tested only due to lack of HW. diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c index 912f116..dc921b2 100644 --- a/drivers/rtc/rtc-snvs.c +++ b/drivers/rtc/rtc-snvs.c @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) } } +static int snvs_rtc_enable_done(int enable, void __iomem *addr) +{ + u32 lpcr = readl(addr + SNVS_LPCR); + + return !!enable ^ !(lpcr & SNVS_LPCR_SRTC_ENV); +} + static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) { unsigned long timeout = jiffies + msecs_to_jiffies(1); @@ -99,18 +106,15 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) spin_unlock_irqrestore(&data->lock, flags); while (1) { - lpcr = readl(data->ioaddr + SNVS_LPCR); + if (snvs_rtc_enable_done(enable, data->ioaddr)) + break; - if (enable) { - if (lpcr & SNVS_LPCR_SRTC_ENV) - break; - } else { - if (!(lpcr & SNVS_LPCR_SRTC_ENV)) + if (time_after(jiffies, timeout)) { + if (snvs_rtc_enable_done(enable, data->ioaddr)) break; + else + return -ETIMEDOUT; } - - if (time_after(jiffies, timeout)) - return -ETIMEDOUT; } return 0; -- 1.7.2.5 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() 2012-08-18 8:10 [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() Lothar Waßmann @ 2012-08-18 12:46 ` Shawn Guo 2012-08-18 13:14 ` Lothar Waßmann 2012-09-18 23:07 ` Andrew Morton 1 sibling, 1 reply; 5+ messages in thread From: Shawn Guo @ 2012-08-18 12:46 UTC (permalink / raw) To: linux-arm-kernel On Sat, Aug 18, 2012 at 10:10:08AM +0200, Lothar Wa?mann wrote: > If snvs_rtc_enable() happens to be descheduled for a period longer > than the timout period, a timeout may be indicated even if the RTC > status has changed meanwhile. Force a status read at the end of the > timeout period to prevent bogus timeout errors. > > > Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de> > --- > drivers/rtc/rtc-snvs.c | 22 +++++++++++++--------- > 1 files changed, 13 insertions(+), 9 deletions(-) > > Compile tested only due to lack of HW. Tested-by: Shawn Guo <shawn.guo@linaro.org> A small nitpick below. > > diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c > index 912f116..dc921b2 100644 > --- a/drivers/rtc/rtc-snvs.c > +++ b/drivers/rtc/rtc-snvs.c > @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) > } > } > > +static int snvs_rtc_enable_done(int enable, void __iomem *addr) Can we rename parameter "addr" to "ioaddr" and put it before "enable", also change "enable" to bool? Regards, Shawn > +{ > + u32 lpcr = readl(addr + SNVS_LPCR); > + > + return !!enable ^ !(lpcr & SNVS_LPCR_SRTC_ENV); > +} > + > static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) > { > unsigned long timeout = jiffies + msecs_to_jiffies(1); > @@ -99,18 +106,15 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) > spin_unlock_irqrestore(&data->lock, flags); > > while (1) { > - lpcr = readl(data->ioaddr + SNVS_LPCR); > + if (snvs_rtc_enable_done(enable, data->ioaddr)) > + break; > > - if (enable) { > - if (lpcr & SNVS_LPCR_SRTC_ENV) > - break; > - } else { > - if (!(lpcr & SNVS_LPCR_SRTC_ENV)) > + if (time_after(jiffies, timeout)) { > + if (snvs_rtc_enable_done(enable, data->ioaddr)) > break; > + else > + return -ETIMEDOUT; > } > - > - if (time_after(jiffies, timeout)) > - return -ETIMEDOUT; > } > > return 0; > -- > 1.7.2.5 > ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() 2012-08-18 12:46 ` Shawn Guo @ 2012-08-18 13:14 ` Lothar Waßmann 2015-05-10 21:42 ` Alexandre Belloni 0 siblings, 1 reply; 5+ messages in thread From: Lothar Waßmann @ 2012-08-18 13:14 UTC (permalink / raw) To: linux-arm-kernel Shawn Guo writes: > On Sat, Aug 18, 2012 at 10:10:08AM +0200, Lothar Wa?mann wrote: > > If snvs_rtc_enable() happens to be descheduled for a period longer > > than the timout period, a timeout may be indicated even if the RTC > > status has changed meanwhile. Force a status read at the end of the > > timeout period to prevent bogus timeout errors. > > > > > > Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de> > > --- > > drivers/rtc/rtc-snvs.c | 22 +++++++++++++--------- > > 1 files changed, 13 insertions(+), 9 deletions(-) > > > > Compile tested only due to lack of HW. > > Tested-by: Shawn Guo <shawn.guo@linaro.org> > > A small nitpick below. > > > > > diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c > > index 912f116..dc921b2 100644 > > --- a/drivers/rtc/rtc-snvs.c > > +++ b/drivers/rtc/rtc-snvs.c > > @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) > > } > > } > > > > +static int snvs_rtc_enable_done(int enable, void __iomem *addr) > > Can we rename parameter "addr" to "ioaddr" and put it before "enable", > also change "enable" to bool? > OK. The resulting assembler code of the patch below is identical to the previous version of this patch. Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de> Tested-by: Shawn Guo <shawn.guo@linaro.org> --- drivers/rtc/rtc-snvs.c | 22 +++++++++++++--------- 1 files changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c index 912f116..a757cb9 100644 --- a/drivers/rtc/rtc-snvs.c +++ b/drivers/rtc/rtc-snvs.c @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) } } +static int snvs_rtc_enable_done(void __iomem *ioaddr, bool enable) +{ + u32 lpcr = readl(ioaddr + SNVS_LPCR); + + return enable ^ !(lpcr & SNVS_LPCR_SRTC_ENV); +} + static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) { unsigned long timeout = jiffies + msecs_to_jiffies(1); @@ -99,18 +106,15 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) spin_unlock_irqrestore(&data->lock, flags); while (1) { - lpcr = readl(data->ioaddr + SNVS_LPCR); + if (snvs_rtc_enable_done(data->ioaddr, enable)) + break; - if (enable) { - if (lpcr & SNVS_LPCR_SRTC_ENV) - break; - } else { - if (!(lpcr & SNVS_LPCR_SRTC_ENV)) + if (time_after(jiffies, timeout)) { + if (snvs_rtc_enable_done(data->ioaddr, enable)) break; + else + return -ETIMEDOUT; } - - if (time_after(jiffies, timeout)) - return -ETIMEDOUT; } return 0; -- 1.7.2.5 Lothar Wa?mann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstra?e 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Gesch?ftsf?hrer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info at karo-electronics.de ___________________________________________________________ ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() 2012-08-18 13:14 ` Lothar Waßmann @ 2015-05-10 21:42 ` Alexandre Belloni 0 siblings, 0 replies; 5+ messages in thread From: Alexandre Belloni @ 2015-05-10 21:42 UTC (permalink / raw) To: linux-arm-kernel Hi Shawn, Lothar, On 18/08/2012 at 15:14:04 +0200, Lothar Wa?mann wrote : > Shawn Guo writes: > > On Sat, Aug 18, 2012 at 10:10:08AM +0200, Lothar Wa?mann wrote: > > > If snvs_rtc_enable() happens to be descheduled for a period longer > > > than the timout period, a timeout may be indicated even if the RTC > > > status has changed meanwhile. Force a status read at the end of the > > > timeout period to prevent bogus timeout errors. > > > > > > > > > Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de> > > > --- > > > drivers/rtc/rtc-snvs.c | 22 +++++++++++++--------- > > > 1 files changed, 13 insertions(+), 9 deletions(-) > > > > > > Compile tested only due to lack of HW. > > > > Tested-by: Shawn Guo <shawn.guo@linaro.org> > > It seems that patch never made it mainline. Can you check if it is still needed? > > A small nitpick below. > > > > > > > > diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c > > > index 912f116..dc921b2 100644 > > > --- a/drivers/rtc/rtc-snvs.c > > > +++ b/drivers/rtc/rtc-snvs.c > > > @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) > > > } > > > } > > > > > > +static int snvs_rtc_enable_done(int enable, void __iomem *addr) > > > > Can we rename parameter "addr" to "ioaddr" and put it before "enable", > > also change "enable" to bool? > > > OK. The resulting assembler code of the patch below is identical to > the previous version of this patch. > > > Signed-off-by: Lothar Wa?mann <LW@KARO-electronics.de> > Tested-by: Shawn Guo <shawn.guo@linaro.org> > --- > drivers/rtc/rtc-snvs.c | 22 +++++++++++++--------- > 1 files changed, 13 insertions(+), 9 deletions(-) > > diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c > index 912f116..a757cb9 100644 > --- a/drivers/rtc/rtc-snvs.c > +++ b/drivers/rtc/rtc-snvs.c > @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) > } > } > > +static int snvs_rtc_enable_done(void __iomem *ioaddr, bool enable) > +{ > + u32 lpcr = readl(ioaddr + SNVS_LPCR); > + > + return enable ^ !(lpcr & SNVS_LPCR_SRTC_ENV); > +} > + > static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) > { > unsigned long timeout = jiffies + msecs_to_jiffies(1); > @@ -99,18 +106,15 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) > spin_unlock_irqrestore(&data->lock, flags); > > while (1) { > - lpcr = readl(data->ioaddr + SNVS_LPCR); > + if (snvs_rtc_enable_done(data->ioaddr, enable)) > + break; > > - if (enable) { > - if (lpcr & SNVS_LPCR_SRTC_ENV) > - break; > - } else { > - if (!(lpcr & SNVS_LPCR_SRTC_ENV)) > + if (time_after(jiffies, timeout)) { > + if (snvs_rtc_enable_done(data->ioaddr, enable)) > break; > + else > + return -ETIMEDOUT; > } > - > - if (time_after(jiffies, timeout)) > - return -ETIMEDOUT; > } > > return 0; -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() 2012-08-18 8:10 [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() Lothar Waßmann 2012-08-18 12:46 ` Shawn Guo @ 2012-09-18 23:07 ` Andrew Morton 1 sibling, 0 replies; 5+ messages in thread From: Andrew Morton @ 2012-09-18 23:07 UTC (permalink / raw) To: linux-arm-kernel On Sat, 18 Aug 2012 10:10:08 +0200 Lothar Wa__mann <LW@karo-electronics.de> wrote: > If snvs_rtc_enable() happens to be descheduled for a period longer > than the timout period, a timeout may be indicated even if the RTC > status has changed meanwhile. Force a status read at the end of the > timeout period to prevent bogus timeout errors. (delayed, sorry) > --- a/drivers/rtc/rtc-snvs.c > +++ b/drivers/rtc/rtc-snvs.c > @@ -81,6 +81,13 @@ static void rtc_write_sync_lp(void __iomem *ioaddr) > } > } > > +static int snvs_rtc_enable_done(int enable, void __iomem *addr) > +{ > + u32 lpcr = readl(addr + SNVS_LPCR); > + > + return !!enable ^ !(lpcr & SNVS_LPCR_SRTC_ENV); > +} > + > static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) > { > unsigned long timeout = jiffies + msecs_to_jiffies(1); > @@ -99,18 +106,15 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) > spin_unlock_irqrestore(&data->lock, flags); > > while (1) { > - lpcr = readl(data->ioaddr + SNVS_LPCR); > + if (snvs_rtc_enable_done(enable, data->ioaddr)) > + break; > > - if (enable) { > - if (lpcr & SNVS_LPCR_SRTC_ENV) > - break; > - } else { > - if (!(lpcr & SNVS_LPCR_SRTC_ENV)) > + if (time_after(jiffies, timeout)) { > + if (snvs_rtc_enable_done(enable, data->ioaddr)) > break; > + else > + return -ETIMEDOUT; > } > - > - if (time_after(jiffies, timeout)) > - return -ETIMEDOUT; > } > > return 0; I think this will have been addressed by http://ozlabs.org/~akpm/mmots/broken-out/rtc-snvs-add-freescale-rtc-snvs-driver-fix.patch? ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-05-10 21:42 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-08-18 8:10 [PATCH] rtc: snvs: improve timeout handling in snvs_rtc_enable() Lothar Waßmann 2012-08-18 12:46 ` Shawn Guo 2012-08-18 13:14 ` Lothar Waßmann 2015-05-10 21:42 ` Alexandre Belloni 2012-09-18 23:07 ` Andrew Morton
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