| Message ID | 1355832418-31692-3-git-send-email-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 12/18/12 04:06, Mark Rutland wrote: > diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c > index f113755..c2dd022 100644 > --- a/kernel/time/tick-broadcast.c > +++ b/kernel/time/tick-broadcast.c > @@ -125,6 +125,21 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) > return ret; > } > > +int tick_receive_broadcast(void) > +{ > + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); > + struct clock_event_device *evt = td->evtdev; > + > + if (!evt) > + return -ENODEV; > + > + if (!evt->event_handler) > + return -EINVAL; > + Does this actually happen? It's not obvious to me how it does. > + evt->event_handler(evt); > + return 0; > +} > + > /* > * Broadcast the event to the cpus, which are set in the mask (mangled). > */
On Tue, Dec 18, 2012 at 10:17:11PM +0000, Stephen Boyd wrote: > On 12/18/12 04:06, Mark Rutland wrote: > > diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c > > index f113755..c2dd022 100644 > > --- a/kernel/time/tick-broadcast.c > > +++ b/kernel/time/tick-broadcast.c > > @@ -125,6 +125,21 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) > > return ret; > > } > > > > +int tick_receive_broadcast(void) > > +{ > > + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); > > + struct clock_event_device *evt = td->evtdev; > > + > > + if (!evt) > > + return -ENODEV; > > + > > + if (!evt->event_handler) > > + return -EINVAL; > > + > > Does this actually happen? It's not obvious to me how it does. Taking a look at it, I don't think it does. Any tick_device's clock_event_device should have an event_handler. I'll drop this check. A tick device might not have a clock_event_device registered in some cases -- the x86 lapic timer has to deal with interrupts pending across a kexec, where interrupts are enabled before local timers are registered. I'm not sure how common this problem might be though, and whether it should be dealt with here or elsewhere. > > + evt->event_handler(evt); > > + return 0; > > +} > > + > > /* > > * Broadcast the event to the cpus, which are set in the mask (mangled). > > */ > > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > Thanks, Mark.
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index 8a7096f..e1089aa 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -161,6 +161,10 @@ clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec) extern void clockevents_suspend(void); extern void clockevents_resume(void); +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +extern int tick_receive_broadcast(void); +#endif + #ifdef CONFIG_GENERIC_CLOCKEVENTS extern void clockevents_notify(unsigned long reason, void *arg); #else diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index f113755..c2dd022 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -125,6 +125,21 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) return ret; } +int tick_receive_broadcast(void) +{ + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); + struct clock_event_device *evt = td->evtdev; + + if (!evt) + return -ENODEV; + + if (!evt->event_handler) + return -EINVAL; + + evt->event_handler(evt); + return 0; +} + /* * Broadcast the event to the cpus, which are set in the mask (mangled). */
Currently the broadcast mechanism used for timers is abstracted by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this ties each clock_event_device driver to a single architecture, even where the driver is otherwise generic. This patch adds a standard path for the receipt of timer broadcasts, so drivers and/or architecture backends need not manage redundant lists of timers for the purpose of routing broadcast timer ticks. Signed-off-by: Mark Rutland <mark.rutland@arm.com> --- include/linux/clockchips.h | 4 ++++ kernel/time/tick-broadcast.c | 15 +++++++++++++++ 2 files changed, 19 insertions(+), 0 deletions(-)