Add a clockevent driver for pxa systems. This patch also removes the pxa
dyntick support since it is not necessary anymore with generic dynamic
tick support
Signed-off-by: Luotao Fu <[email protected]>
Signed-off-by: Sascha Hauer <[email protected]>
---
arch/arm/mach-pxa/time.c | 106 ++++++++++++++++++++++-------------------------
1 file changed, 51 insertions(+), 55 deletions(-)
Index: arch/arm/mach-pxa/time.c
===================================================================
--- a/arch/arm/mach-pxa/time.c.orig
+++ b/arch/arm/mach-pxa/time.c
@@ -19,6 +19,7 @@
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <asm/system.h>
#include <asm/hardware.h>
@@ -29,6 +30,50 @@
#include <asm/mach/time.h>
#include <asm/arch/pxa-regs.h>
+static u32 clockevent_mode = 0;
+
+static void pxa_set_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ OSMR0 = OSCR + evt;
+}
+
+static void pxa_set_mode(enum clock_event_mode mode, struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_PERIODIC:
+ case CLOCK_EVT_ONESHOT:
+ OIER |= OIER_E0;
+ break;
+
+ case CLOCK_EVT_SHUTDOWN:
+ OIER &= ~OIER_E0;
+ return;
+ }
+ clockevent_mode = mode;
+}
+
+static struct clock_event_device clockevent_pxa = {
+ .name = "pxa_timer1",
+ .capabilities = CLOCK_CAP_NEXTEVT | CLOCK_CAP_TICK |
+ CLOCK_CAP_UPDATE | CLOCK_CAP_PROFILE,
+ .shift = 32,
+ .set_mode = pxa_set_mode,
+ .set_next_event = pxa_set_next_event,
+};
+
+static int __init pxa_clockevent_init(void)
+{
+ clockevent_pxa.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC,
+ clockevent_pxa.shift);
+ clockevent_pxa.max_delta_ns =
+ clockevent_delta2ns(0xfffffffe, &clockevent_pxa);
+ clockevent_pxa.min_delta_ns =
+ clockevent_delta2ns(0xf, &clockevent_pxa);
+ register_local_clockevent(&clockevent_pxa);
+
+ return 0;
+}
static inline unsigned long pxa_get_rtc_time(void)
{
@@ -49,25 +94,11 @@ static int pxa_set_rtc(void)
return 0;
}
-#ifdef CONFIG_NO_IDLE_HZ
-static unsigned long initial_match;
-static int match_posponed;
-#endif
-
static irqreturn_t
pxa_timer_interrupt(int irq, void *dev_id)
{
int next_match;
- write_seqlock(&xtime_lock);
-
-#ifdef CONFIG_NO_IDLE_HZ
- if (match_posponed) {
- match_posponed = 0;
- OSMR0 = initial_match;
- }
-#endif
-
/* Loop until we get ahead of the free running timer.
* This ensures an exact clock tick count and time accuracy.
* Since IRQs are disabled at this point, coherence between
@@ -85,13 +116,15 @@ pxa_timer_interrupt(int irq, void *dev_i
* exactly one tick period which should be a pretty rare event.
*/
do {
- timer_tick();
+ clockevent_pxa.event_handler();
OSSR = OSSR_M0; /* Clear match on timer 0 */
+
+ if (clockevent_mode != CLOCK_EVT_PERIODIC)
+ break;
+
next_match = (OSMR0 += LATCH);
} while( (signed long)(next_match - OSCR) <= 8 );
- write_sequnlock(&xtime_lock);
-
return IRQ_HANDLED;
}
@@ -141,44 +174,10 @@ static void __init pxa_timer_init(void)
clocksource_pxa.mult =
clocksource_hz2mult(CLOCK_TICK_RATE, clocksource_pxa.shift);
clocksource_register(&clocksource_pxa);
-}
-
-#ifdef CONFIG_NO_IDLE_HZ
-static int pxa_dyn_tick_enable_disable(void)
-{
- /* nothing to do */
- return 0;
-}
-
-static void pxa_dyn_tick_reprogram(unsigned long ticks)
-{
- if (ticks > 1) {
- initial_match = OSMR0;
- OSMR0 = initial_match + ticks * LATCH;
- match_posponed = 1;
- }
-}
-static irqreturn_t
-pxa_dyn_tick_handler(int irq, void *dev_id)
-{
- if (match_posponed) {
- match_posponed = 0;
- OSMR0 = initial_match;
- if ( (signed long)(initial_match - OSCR) <= 8 )
- return pxa_timer_interrupt(irq, dev_id);
- }
- return IRQ_NONE;
+ pxa_clockevent_init();
}
-static struct dyn_tick_timer pxa_dyn_tick = {
- .enable = pxa_dyn_tick_enable_disable,
- .disable = pxa_dyn_tick_enable_disable,
- .reprogram = pxa_dyn_tick_reprogram,
- .handler = pxa_dyn_tick_handler,
-};
-#endif
-
#ifdef CONFIG_PM
static unsigned long osmr[4], oier;
@@ -213,7 +212,4 @@ struct sys_timer pxa_timer = {
.init = pxa_timer_init,
.suspend = pxa_timer_suspend,
.resume = pxa_timer_resume,
-#ifdef CONFIG_NO_IDLE_HZ
- .dyn_tick = &pxa_dyn_tick,
-#endif
};
--
Dipl.-Ing. Sascha Hauer | http://www.pengutronix.de
Pengutronix - Linux Solutions for Science and Industry
Handelsregister: Amtsgericht Hildesheim, HRA 2686
Hannoversche Str. 2, 31134 Hildesheim, Germany
Phone: +49-5121-206917-0 | Fax: +49-5121-206917-9
On Tue, 9 Jan 2007 [email protected] wrote:
> Add a clockevent driver for pxa systems. This patch also removes the pxa
> dyntick support since it is not necessary anymore with generic dynamic
> tick support
>
> Signed-off-by: Luotao Fu <[email protected]>
> Signed-off-by: Sascha Hauer <[email protected]>
>
> ---
> arch/arm/mach-pxa/time.c | 106 ++++++++++++++++++++++-------------------------
> 1 file changed, 51 insertions(+), 55 deletions(-)
>
> Index: arch/arm/mach-pxa/time.c
> ===================================================================
> --- a/arch/arm/mach-pxa/time.c.orig
> +++ b/arch/arm/mach-pxa/time.c
> @@ -19,6 +19,7 @@
> #include <linux/errno.h>
> #include <linux/sched.h>
> #include <linux/clocksource.h>
> +#include <linux/clockchips.h>
>
> #include <asm/system.h>
> #include <asm/hardware.h>
> @@ -29,6 +30,50 @@
> #include <asm/mach/time.h>
> #include <asm/arch/pxa-regs.h>
>
> +static u32 clockevent_mode = 0;
> +
> +static void pxa_set_next_event(unsigned long evt,
> + struct clock_event_device *unused)
> +{
> + OSMR0 = OSCR + evt;
> +}
This doesn't work for me in various nasty ways. Please, check for a
minimum delay or loop to get ahead of time. See code in the "old" timer
ISR. See how it unconditionally adds at least 10 ticks...
Thanks
Guennadi
---
Guennadi Liakhovetski
On Fri, 2007-01-19 at 20:13 +0100, Guennadi Liakhovetski wrote:
> > +static u32 clockevent_mode = 0;
> > +
> > +static void pxa_set_next_event(unsigned long evt,
> > + struct clock_event_device *unused)
> > +{
> > + OSMR0 = OSCR + evt;
> > +}
>
> This doesn't work for me in various nasty ways. Please, check for a
> minimum delay or loop to get ahead of time. See code in the "old" timer
> ISR. See how it unconditionally adds at least 10 ticks...
I added support for match register based devices and you want to do
something like this:
static int hpet_next_event(unsigned long delta,
struct clock_event_device *evt)
{
unsigned long cnt;
cnt = hpet_readl(HPET_COUNTER);
cnt += delta;
hpet_writel(cnt, HPET_T0_CMP);
return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0);
}
The generic code takes care of the already expired event.
tglx
On Fri, 19 Jan 2007, Thomas Gleixner wrote:
> On Fri, 2007-01-19 at 20:13 +0100, Guennadi Liakhovetski wrote:
> > > +static u32 clockevent_mode = 0;
> > > +
> > > +static void pxa_set_next_event(unsigned long evt,
> > > + struct clock_event_device *unused)
> > > +{
> > > + OSMR0 = OSCR + evt;
> > > +}
> >
> > This doesn't work for me in various nasty ways. Please, check for a
> > minimum delay or loop to get ahead of time. See code in the "old" timer
> > ISR. See how it unconditionally adds at least 10 ticks...
>
> I added support for match register based devices and you want to do
> something like this:
>
> static int hpet_next_event(unsigned long delta,
> struct clock_event_device *evt)
> {
> unsigned long cnt;
>
> cnt = hpet_readl(HPET_COUNTER);
> cnt += delta;
> hpet_writel(cnt, HPET_T0_CMP);
>
> return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0);
> }
>
> The generic code takes care of the already expired event.
The thing is - 2.6.20-rc5-rt3 didn't provide clockevent on PXA, so, I took
Sascha's patch instead of my own, which I've been using with 2.6.18, as
his patches were already submitted to various lists and had chances to
become mainline. And strait away it didn't work. The code above seems to
be doing something close to Sascha's patch, so, I expect it would behave
in the same way. And until I introduced a minimum increment for the match
register, it didn't work. I either got hangs, or WARN_ON dumps about "time
warp detected". I think, any timer related code for PXA has to be tested
on real hardware under significant (real-time) load before going upstream.
Haven't tested -rt7 though, so, maybe it is already handled there?
Thanks
Guennadi
---
Guennadi Liakhovetski
On Sat, 2007-01-20 at 17:08 +0100, Guennadi Liakhovetski wrote:
> > static int hpet_next_event(unsigned long delta,
> > struct clock_event_device *evt)
> > {
> > unsigned long cnt;
> >
> > cnt = hpet_readl(HPET_COUNTER);
> > cnt += delta;
> > hpet_writel(cnt, HPET_T0_CMP);
> >
> > return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0);
> > }
> >
> > The generic code takes care of the already expired event.
>
> The thing is - 2.6.20-rc5-rt3 didn't provide clockevent on PXA, so, I took
> Sascha's patch instead of my own, which I've been using with 2.6.18, as
> his patches were already submitted to various lists and had chances to
> become mainline. And strait away it didn't work. The code above seems to
> be doing something close to Sascha's patch, so, I expect it would behave
> in the same way. And until I introduced a minimum increment for the match
> register, it didn't work. I either got hangs, or WARN_ON dumps about "time
> warp detected". I think, any timer related code for PXA has to be tested
> on real hardware under significant (real-time) load before going upstream.
> Haven't tested -rt7 though, so, maybe it is already handled there?
No, as I'm reworking clock events a bit and I added the handling for the
match register based devices. The above will catch the event in the past
and the generic code handles that. Will be on -rt soon.
tglx