* [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading @ 2014-03-05 22:11 ` Stefan Agner 0 siblings, 0 replies; 7+ messages in thread From: Stefan Agner @ 2014-03-05 22:11 UTC (permalink / raw) To: linux-arm-kernel Vybrids PIT register is monitonic decreasing. However, sched_clock reading needs to be monitonic increasing. Use bitwise not to get the complement of the clock register. This fixes the clock going backward. Also, the clock now starts at 0 since we load the register with the maximum value at start. Signed-off-by: Stefan Agner <stefan@agner.ch> --- drivers/clocksource/vf_pit_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c index 02821b0..a918bc4 100644 --- a/drivers/clocksource/vf_pit_timer.c +++ b/drivers/clocksource/vf_pit_timer.c @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) static u64 pit_read_sched_clock(void) { - return __raw_readl(clksrc_base + PITCVAL); + return ~__raw_readl(clksrc_base + PITCVAL); } static int __init pit_clocksource_init(unsigned long rate) -- 1.9.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading @ 2014-03-05 22:11 ` Stefan Agner 0 siblings, 0 replies; 7+ messages in thread From: Stefan Agner @ 2014-03-05 22:11 UTC (permalink / raw) To: daniel.lezcano, tglx, shawn.guo, linux Cc: linux-arm-kernel, linux-kernel, Stefan Agner Vybrids PIT register is monitonic decreasing. However, sched_clock reading needs to be monitonic increasing. Use bitwise not to get the complement of the clock register. This fixes the clock going backward. Also, the clock now starts at 0 since we load the register with the maximum value at start. Signed-off-by: Stefan Agner <stefan@agner.ch> --- drivers/clocksource/vf_pit_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c index 02821b0..a918bc4 100644 --- a/drivers/clocksource/vf_pit_timer.c +++ b/drivers/clocksource/vf_pit_timer.c @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) static u64 pit_read_sched_clock(void) { - return __raw_readl(clksrc_base + PITCVAL); + return ~__raw_readl(clksrc_base + PITCVAL); } static int __init pit_clocksource_init(unsigned long rate) -- 1.9.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading 2014-03-05 22:11 ` Stefan Agner @ 2014-03-06 1:45 ` Shawn Guo -1 siblings, 0 replies; 7+ messages in thread From: Shawn Guo @ 2014-03-06 1:45 UTC (permalink / raw) To: linux-arm-kernel On Wed, Mar 05, 2014 at 11:11:08PM +0100, Stefan Agner wrote: > Vybrids PIT register is monitonic decreasing. However, sched_clock > reading needs to be monitonic increasing. Use bitwise not to get > the complement of the clock register. This fixes the clock going > backward. Also, the clock now starts at 0 since we load the > register with the maximum value at start. > > Signed-off-by: Stefan Agner <stefan@agner.ch> Looks correct to me, so Acked-by: Shawn Guo <shawn.guo@linaro.org> But I also copied the driver author Jingchang to see if he has any comment. Shawn > --- > drivers/clocksource/vf_pit_timer.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c > index 02821b0..a918bc4 100644 > --- a/drivers/clocksource/vf_pit_timer.c > +++ b/drivers/clocksource/vf_pit_timer.c > @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) > > static u64 pit_read_sched_clock(void) > { > - return __raw_readl(clksrc_base + PITCVAL); > + return ~__raw_readl(clksrc_base + PITCVAL); > } > > static int __init pit_clocksource_init(unsigned long rate) > -- > 1.9.0 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading @ 2014-03-06 1:45 ` Shawn Guo 0 siblings, 0 replies; 7+ messages in thread From: Shawn Guo @ 2014-03-06 1:45 UTC (permalink / raw) To: Stefan Agner Cc: daniel.lezcano, tglx, linux, linux-arm-kernel, linux-kernel, Jingchang Lu On Wed, Mar 05, 2014 at 11:11:08PM +0100, Stefan Agner wrote: > Vybrids PIT register is monitonic decreasing. However, sched_clock > reading needs to be monitonic increasing. Use bitwise not to get > the complement of the clock register. This fixes the clock going > backward. Also, the clock now starts at 0 since we load the > register with the maximum value at start. > > Signed-off-by: Stefan Agner <stefan@agner.ch> Looks correct to me, so Acked-by: Shawn Guo <shawn.guo@linaro.org> But I also copied the driver author Jingchang to see if he has any comment. Shawn > --- > drivers/clocksource/vf_pit_timer.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c > index 02821b0..a918bc4 100644 > --- a/drivers/clocksource/vf_pit_timer.c > +++ b/drivers/clocksource/vf_pit_timer.c > @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) > > static u64 pit_read_sched_clock(void) > { > - return __raw_readl(clksrc_base + PITCVAL); > + return ~__raw_readl(clksrc_base + PITCVAL); > } > > static int __init pit_clocksource_init(unsigned long rate) > -- > 1.9.0 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading 2014-03-06 1:45 ` Shawn Guo @ 2014-03-06 3:18 ` Jingchang Lu -1 siblings, 0 replies; 7+ messages in thread From: Jingchang Lu @ 2014-03-06 3:18 UTC (permalink / raw) To: linux-arm-kernel > -----Original Message----- > From: Shawn Guo [mailto:shawn.guo at linaro.org] > Sent: Thursday, March 06, 2014 9:46 AM > To: Stefan Agner > Cc: daniel.lezcano at linaro.org; tglx at linutronix.de; linux at arm.linux.org.uk; > linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org; Lu > Jingchang-B35083 > Subject: Re: [PATCH] clocksource: vf_pit_timer: use complement for > sched_clock reading > > On Wed, Mar 05, 2014 at 11:11:08PM +0100, Stefan Agner wrote: > > Vybrids PIT register is monitonic decreasing. However, sched_clock > > reading needs to be monitonic increasing. Use bitwise not to get the > > complement of the clock register. This fixes the clock going backward. > > Also, the clock now starts at 0 since we load the register with the > > maximum value at start. > > > > Signed-off-by: Stefan Agner <stefan@agner.ch> > > Looks correct to me, so > > Acked-by: Shawn Guo <shawn.guo@linaro.org> > > But I also copied the driver author Jingchang to see if he has any > comment. > > Shawn > The fix is correct, thanks. Best Regards, Jingchang > > --- > > drivers/clocksource/vf_pit_timer.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/clocksource/vf_pit_timer.c > > b/drivers/clocksource/vf_pit_timer.c > > index 02821b0..a918bc4 100644 > > --- a/drivers/clocksource/vf_pit_timer.c > > +++ b/drivers/clocksource/vf_pit_timer.c > > @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) > > > > static u64 pit_read_sched_clock(void) { > > - return __raw_readl(clksrc_base + PITCVAL); > > + return ~__raw_readl(clksrc_base + PITCVAL); > > } > > > > static int __init pit_clocksource_init(unsigned long rate) > > -- > > 1.9.0 > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading @ 2014-03-06 3:18 ` Jingchang Lu 0 siblings, 0 replies; 7+ messages in thread From: Jingchang Lu @ 2014-03-06 3:18 UTC (permalink / raw) To: Shawn Guo, Stefan Agner Cc: daniel.lezcano@linaro.org, tglx@linutronix.de, linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1867 bytes --] > -----Original Message----- > From: Shawn Guo [mailto:shawn.guo@linaro.org] > Sent: Thursday, March 06, 2014 9:46 AM > To: Stefan Agner > Cc: daniel.lezcano@linaro.org; tglx@linutronix.de; linux@arm.linux.org.uk; > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Lu > Jingchang-B35083 > Subject: Re: [PATCH] clocksource: vf_pit_timer: use complement for > sched_clock reading > > On Wed, Mar 05, 2014 at 11:11:08PM +0100, Stefan Agner wrote: > > Vybrids PIT register is monitonic decreasing. However, sched_clock > > reading needs to be monitonic increasing. Use bitwise not to get the > > complement of the clock register. This fixes the clock going backward. > > Also, the clock now starts at 0 since we load the register with the > > maximum value at start. > > > > Signed-off-by: Stefan Agner <stefan@agner.ch> > > Looks correct to me, so > > Acked-by: Shawn Guo <shawn.guo@linaro.org> > > But I also copied the driver author Jingchang to see if he has any > comment. > > Shawn > The fix is correct, thanks. Best Regards, Jingchang > > --- > > drivers/clocksource/vf_pit_timer.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/clocksource/vf_pit_timer.c > > b/drivers/clocksource/vf_pit_timer.c > > index 02821b0..a918bc4 100644 > > --- a/drivers/clocksource/vf_pit_timer.c > > +++ b/drivers/clocksource/vf_pit_timer.c > > @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) > > > > static u64 pit_read_sched_clock(void) { > > - return __raw_readl(clksrc_base + PITCVAL); > > + return ~__raw_readl(clksrc_base + PITCVAL); > > } > > > > static int __init pit_clocksource_init(unsigned long rate) > > -- > > 1.9.0 > > ÿôèº{.nÇ+‰·Ÿ®‰†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a¢f£¢·hšïêÿ‘êçz_è®\x03(階ŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨èÚ&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥ ^ permalink raw reply [flat|nested] 7+ messages in thread
* [tip:timers/urgent] clocksource: vf_pit_timer: use complement for sched_clock reading 2014-03-05 22:11 ` Stefan Agner (?) (?) @ 2014-03-06 10:37 ` tip-bot for Stefan Agner -1 siblings, 0 replies; 7+ messages in thread From: tip-bot for Stefan Agner @ 2014-03-06 10:37 UTC (permalink / raw) To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, tglx, shawn.guo, stefan Commit-ID: 224aa3ed45c8735ae02bb2ecca002409fa6aa772 Gitweb: http://git.kernel.org/tip/224aa3ed45c8735ae02bb2ecca002409fa6aa772 Author: Stefan Agner <stefan@agner.ch> AuthorDate: Wed, 5 Mar 2014 23:11:08 +0100 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Thu, 6 Mar 2014 11:34:14 +0100 clocksource: vf_pit_timer: use complement for sched_clock reading Vybrids PIT register is monitonic decreasing. However, sched_clock reading needs to be monitonic increasing. Use bitwise not to get the complement of the clock register. This fixes the clock going backward. Also, the clock now starts at 0 since we load the register with the maximum value at start. Signed-off-by: Stefan Agner <stefan@agner.ch> Acked-by: Shawn Guo <shawn.guo@linaro.org> Cc: daniel.lezcano@linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux@arm.linux.org.uk Link: http://lkml.kernel.org/r/d25af915993aec1b486be653eb86f748ddef54fe.1394057313.git.stefan@agner.ch Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- drivers/clocksource/vf_pit_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c index 02821b0..a918bc4 100644 --- a/drivers/clocksource/vf_pit_timer.c +++ b/drivers/clocksource/vf_pit_timer.c @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) static u64 pit_read_sched_clock(void) { - return __raw_readl(clksrc_base + PITCVAL); + return ~__raw_readl(clksrc_base + PITCVAL); } static int __init pit_clocksource_init(unsigned long rate) ^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2014-03-06 10:37 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-03-05 22:11 [PATCH] clocksource: vf_pit_timer: use complement for sched_clock reading Stefan Agner 2014-03-05 22:11 ` Stefan Agner 2014-03-06 1:45 ` Shawn Guo 2014-03-06 1:45 ` Shawn Guo 2014-03-06 3:18 ` Jingchang Lu 2014-03-06 3:18 ` Jingchang Lu 2014-03-06 10:37 ` [tip:timers/urgent] " tip-bot for Stefan Agner
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