* [PATCH 1/4] powerpc/time: Use clockevents_calc_mult_shift
2011-11-03 0:59 [PATCH 0/4] PowerPC time fixes Anton Blanchard
@ 2011-11-03 0:59 ` Anton Blanchard
2011-11-03 0:59 ` [PATCH 2/4] powerpc/time: Use clocksource_register_hz Anton Blanchard
` (2 subsequent siblings)
3 siblings, 0 replies; 8+ messages in thread
From: Anton Blanchard @ 2011-11-03 0:59 UTC (permalink / raw)
To: benh, paulus, johnstul; +Cc: linuxppc-dev
We can use clockevents_calc_mult_shift instead of doing all
the work ourselves.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-build/arch/powerpc/kernel/time.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:55.225606490 +1100
+++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100
@@ -112,8 +112,6 @@ static void decrementer_set_mode(enum cl
static struct clock_event_device decrementer_clockevent = {
.name = "decrementer",
.rating = 200,
- .shift = 0, /* To be filled in */
- .mult = 0, /* To be filled in */
.irq = 0,
.set_next_event = decrementer_set_next_event,
.set_mode = decrementer_set_mode,
@@ -904,31 +902,6 @@ static void decrementer_set_mode(enum cl
decrementer_set_next_event(DECREMENTER_MAX, dev);
}
-static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec,
- int shift)
-{
- uint64_t tmp = ((uint64_t)ticks) << shift;
-
- do_div(tmp, nsec);
- return tmp;
-}
-
-static void __init setup_clockevent_multiplier(unsigned long hz)
-{
- u64 mult, shift = 32;
-
- while (1) {
- mult = div_sc64(hz, NSEC_PER_SEC, shift);
- if (mult && (mult >> 32UL) == 0UL)
- break;
-
- shift--;
- }
-
- decrementer_clockevent.shift = shift;
- decrementer_clockevent.mult = mult;
-}
-
static void register_decrementer_clockevent(int cpu)
{
struct clock_event_device *dec = &per_cpu(decrementers, cpu).event;
@@ -946,7 +919,8 @@ static void __init init_decrementer_cloc
{
int cpu = smp_processor_id();
- setup_clockevent_multiplier(ppc_tb_freq);
+ clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
+
decrementer_clockevent.max_delta_ns =
clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
decrementer_clockevent.min_delta_ns =
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH 2/4] powerpc/time: Use clocksource_register_hz
2011-11-03 0:59 [PATCH 0/4] PowerPC time fixes Anton Blanchard
2011-11-03 0:59 ` [PATCH 1/4] powerpc/time: Use clockevents_calc_mult_shift Anton Blanchard
@ 2011-11-03 0:59 ` Anton Blanchard
2011-11-03 13:14 ` John Stultz
2011-11-03 0:59 ` [PATCH 3/4] powerpc/time: Remove unnecessary sanity check of decrementer expiration Anton Blanchard
2011-11-03 0:59 ` [PATCH 4/4] powerpc/time: Fix some style issues Anton Blanchard
3 siblings, 1 reply; 8+ messages in thread
From: Anton Blanchard @ 2011-11-03 0:59 UTC (permalink / raw)
To: benh, paulus, johnstul; +Cc: linuxppc-dev
Use clocksource_register_hz which calculates the shift/mult
factors for us.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-build/arch/powerpc/kernel/time.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100
+++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:20:00.965704053 +1100
@@ -86,8 +86,6 @@ static struct clocksource clocksource_rt
.rating = 400,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.mask = CLOCKSOURCE_MASK(64),
- .shift = 22,
- .mult = 0, /* To be filled in */
.read = rtc_read,
};
@@ -97,8 +95,6 @@ static struct clocksource clocksource_ti
.rating = 400,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.mask = CLOCKSOURCE_MASK(64),
- .shift = 22,
- .mult = 0, /* To be filled in */
.read = timebase_read,
};
@@ -875,9 +871,7 @@ static void __init clocksource_init(void
else
clock = &clocksource_timebase;
- clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift);
-
- if (clocksource_register(clock)) {
+ if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
printk(KERN_ERR "clocksource: %s is already registered\n",
clock->name);
return;
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 2/4] powerpc/time: Use clocksource_register_hz
2011-11-03 0:59 ` [PATCH 2/4] powerpc/time: Use clocksource_register_hz Anton Blanchard
@ 2011-11-03 13:14 ` John Stultz
2011-11-05 0:55 ` Paul Mackerras
0 siblings, 1 reply; 8+ messages in thread
From: John Stultz @ 2011-11-03 13:14 UTC (permalink / raw)
To: Anton Blanchard; +Cc: paulus, linuxppc-dev
On Thu, 2011-11-03 at 11:59 +1100, Anton Blanchard wrote:
> plain text document attachment (clock3)
> Use clocksource_register_hz which calculates the shift/mult
> factors for us.
>
> Signed-off-by: Anton Blanchard <anton@samba.org>
> ---
>
> Index: linux-build/arch/powerpc/kernel/time.c
> ===================================================================
> --- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100
> +++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:20:00.965704053 +1100
> @@ -86,8 +86,6 @@ static struct clocksource clocksource_rt
> .rating = 400,
> .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> .mask = CLOCKSOURCE_MASK(64),
> - .shift = 22,
> - .mult = 0, /* To be filled in */
> .read = rtc_read,
> };
>
> @@ -97,8 +95,6 @@ static struct clocksource clocksource_ti
> .rating = 400,
> .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> .mask = CLOCKSOURCE_MASK(64),
> - .shift = 22,
> - .mult = 0, /* To be filled in */
> .read = timebase_read,
> };
So I've held off on ppc conversion to clocksource_register_hz due to the
fact that the ppc vdso gettimeofday at least used to make assumptions
that shift was 22.
Is that no longer the case?
thanks
-john
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/4] powerpc/time: Use clocksource_register_hz
2011-11-03 13:14 ` John Stultz
@ 2011-11-05 0:55 ` Paul Mackerras
2011-11-07 18:26 ` john stultz
0 siblings, 1 reply; 8+ messages in thread
From: Paul Mackerras @ 2011-11-05 0:55 UTC (permalink / raw)
To: John Stultz; +Cc: linuxppc-dev, Anton Blanchard
On Thu, Nov 03, 2011 at 09:14:44AM -0400, John Stultz wrote:
> On Thu, 2011-11-03 at 11:59 +1100, Anton Blanchard wrote:
> > plain text document attachment (clock3)
> > Use clocksource_register_hz which calculates the shift/mult
> > factors for us.
> >
> > Signed-off-by: Anton Blanchard <anton@samba.org>
> > ---
> >
> > Index: linux-build/arch/powerpc/kernel/time.c
> > ===================================================================
> > --- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100
> > +++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:20:00.965704053 +1100
> > @@ -86,8 +86,6 @@ static struct clocksource clocksource_rt
> > .rating = 400,
> > .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> > .mask = CLOCKSOURCE_MASK(64),
> > - .shift = 22,
> > - .mult = 0, /* To be filled in */
> > .read = rtc_read,
> > };
> >
> > @@ -97,8 +95,6 @@ static struct clocksource clocksource_ti
> > .rating = 400,
> > .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> > .mask = CLOCKSOURCE_MASK(64),
> > - .shift = 22,
> > - .mult = 0, /* To be filled in */
> > .read = timebase_read,
> > };
>
> So I've held off on ppc conversion to clocksource_register_hz due to the
> fact that the ppc vdso gettimeofday at least used to make assumptions
> that shift was 22.
>
> Is that no longer the case?
It is still the case; specifically, update_vsyscall() in
arch/powerpc/kernel/time.c converts a multiplier value to a 'tb_to_xs'
multiplier (timebase to xsec conversion factor, where 1 xsec = 2^-20
seconds) using a factor which assumes a shift of 22. The factor needs
to be 2^(20 + 64 - shift) / 1e9, so we could accommodate other shift
values by changing the line that computes new_tb_to_xs to do
new_tb_to_xs = (u64) mult * (19342813113834067ULL >> shift);
assuming the shift value is easily available to update_vsyscall
(I assume it would be clock->shift).
Paul.
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 2/4] powerpc/time: Use clocksource_register_hz
2011-11-05 0:55 ` Paul Mackerras
@ 2011-11-07 18:26 ` john stultz
0 siblings, 0 replies; 8+ messages in thread
From: john stultz @ 2011-11-07 18:26 UTC (permalink / raw)
To: Paul Mackerras; +Cc: linuxppc-dev, Anton Blanchard
On Sat, 2011-11-05 at 11:55 +1100, Paul Mackerras wrote:
> On Thu, Nov 03, 2011 at 09:14:44AM -0400, John Stultz wrote:
> > On Thu, 2011-11-03 at 11:59 +1100, Anton Blanchard wrote:
> > > plain text document attachment (clock3)
> > > Use clocksource_register_hz which calculates the shift/mult
> > > factors for us.
> > >
> > > Signed-off-by: Anton Blanchard <anton@samba.org>
> > > ---
> > >
> > > Index: linux-build/arch/powerpc/kernel/time.c
> > > ===================================================================
> > > --- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100
> > > +++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:20:00.965704053 +1100
> > > @@ -86,8 +86,6 @@ static struct clocksource clocksource_rt
> > > .rating = 400,
> > > .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> > > .mask = CLOCKSOURCE_MASK(64),
> > > - .shift = 22,
> > > - .mult = 0, /* To be filled in */
> > > .read = rtc_read,
> > > };
> > >
> > > @@ -97,8 +95,6 @@ static struct clocksource clocksource_ti
> > > .rating = 400,
> > > .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> > > .mask = CLOCKSOURCE_MASK(64),
> > > - .shift = 22,
> > > - .mult = 0, /* To be filled in */
> > > .read = timebase_read,
> > > };
> >
> > So I've held off on ppc conversion to clocksource_register_hz due to the
> > fact that the ppc vdso gettimeofday at least used to make assumptions
> > that shift was 22.
> >
> > Is that no longer the case?
>
> It is still the case; specifically, update_vsyscall() in
> arch/powerpc/kernel/time.c converts a multiplier value to a 'tb_to_xs'
> multiplier (timebase to xsec conversion factor, where 1 xsec = 2^-20
> seconds) using a factor which assumes a shift of 22. The factor needs
> to be 2^(20 + 64 - shift) / 1e9, so we could accommodate other shift
> values by changing the line that computes new_tb_to_xs to do
>
> new_tb_to_xs = (u64) mult * (19342813113834067ULL >> shift);
>
> assuming the shift value is easily available to update_vsyscall
> (I assume it would be clock->shift).
Ok. That sounds reasonable. clock->shift should be correct there.
thanks
-john
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 3/4] powerpc/time: Remove unnecessary sanity check of decrementer expiration
2011-11-03 0:59 [PATCH 0/4] PowerPC time fixes Anton Blanchard
2011-11-03 0:59 ` [PATCH 1/4] powerpc/time: Use clockevents_calc_mult_shift Anton Blanchard
2011-11-03 0:59 ` [PATCH 2/4] powerpc/time: Use clocksource_register_hz Anton Blanchard
@ 2011-11-03 0:59 ` Anton Blanchard
2011-11-03 0:59 ` [PATCH 4/4] powerpc/time: Fix some style issues Anton Blanchard
3 siblings, 0 replies; 8+ messages in thread
From: Anton Blanchard @ 2011-11-03 0:59 UTC (permalink / raw)
To: benh, paulus, johnstul; +Cc: linuxppc-dev
The clockevents code uses max_delta_ns to avoid calling a clockevent
with too large a value.
Remove the redundant version of this in the timer_interrupt code.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-build/arch/powerpc/kernel/time.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:20:00.965704053 +1100
+++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:20:02.117723634 +1100
@@ -114,12 +114,7 @@ static struct clock_event_device decreme
.features = CLOCK_EVT_FEAT_ONESHOT,
};
-struct decrementer_clock {
- struct clock_event_device event;
- u64 next_tb;
-};
-
-static DEFINE_PER_CPU(struct decrementer_clock, decrementers);
+static DEFINE_PER_CPU(struct clock_event_device, decrementers);
#ifdef CONFIG_PPC_ISERIES
static unsigned long __initdata iSeries_recal_titan;
@@ -570,9 +565,7 @@ void arch_irq_work_raise(void)
void timer_interrupt(struct pt_regs * regs)
{
struct pt_regs *old_regs;
- struct decrementer_clock *decrementer = &__get_cpu_var(decrementers);
- struct clock_event_device *evt = &decrementer->event;
- u64 now;
+ struct clock_event_device *evt = &__get_cpu_var(decrementers);
/* Ensure a positive value is written to the decrementer, or else
* some CPUs will continue to take decrementer exceptions.
@@ -607,16 +600,7 @@ void timer_interrupt(struct pt_regs * re
get_lppaca()->int_dword.fields.decr_int = 0;
#endif
- now = get_tb_or_rtc();
- if (now >= decrementer->next_tb) {
- decrementer->next_tb = ~(u64)0;
- if (evt->event_handler)
- evt->event_handler(evt);
- } else {
- now = decrementer->next_tb - now;
- if (now <= DECREMENTER_MAX)
- set_dec((int)now);
- }
+ evt->event_handler(evt);
#ifdef CONFIG_PPC_ISERIES
if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending())
@@ -884,7 +868,6 @@ static void __init clocksource_init(void
static int decrementer_set_next_event(unsigned long evt,
struct clock_event_device *dev)
{
- __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt;
set_dec(evt);
return 0;
}
@@ -898,7 +881,7 @@ static void decrementer_set_mode(enum cl
static void register_decrementer_clockevent(int cpu)
{
- struct clock_event_device *dec = &per_cpu(decrementers, cpu).event;
+ struct clock_event_device *dec = &per_cpu(decrementers, cpu);
*dec = decrementer_clockevent;
dec->cpumask = cpumask_of(cpu);
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH 4/4] powerpc/time: Fix some style issues
2011-11-03 0:59 [PATCH 0/4] PowerPC time fixes Anton Blanchard
` (2 preceding siblings ...)
2011-11-03 0:59 ` [PATCH 3/4] powerpc/time: Remove unnecessary sanity check of decrementer expiration Anton Blanchard
@ 2011-11-03 0:59 ` Anton Blanchard
3 siblings, 0 replies; 8+ messages in thread
From: Anton Blanchard @ 2011-11-03 0:59 UTC (permalink / raw)
To: benh, paulus, johnstul; +Cc: linuxppc-dev
Fix some formatting issues and use the DECREMENTER_MAX
define instead of 0x7fffffff.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-build/arch/powerpc/kernel/time.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:20:02.117723634 +1100
+++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:20:03.101740361 +1100
@@ -82,20 +82,20 @@
static cycle_t rtc_read(struct clocksource *);
static struct clocksource clocksource_rtc = {
- .name = "rtc",
- .rating = 400,
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
- .mask = CLOCKSOURCE_MASK(64),
- .read = rtc_read,
+ .name = "rtc",
+ .rating = 400,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .mask = CLOCKSOURCE_MASK(64),
+ .read = rtc_read,
};
static cycle_t timebase_read(struct clocksource *);
static struct clocksource clocksource_timebase = {
- .name = "timebase",
- .rating = 400,
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
- .mask = CLOCKSOURCE_MASK(64),
- .read = timebase_read,
+ .name = "timebase",
+ .rating = 400,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .mask = CLOCKSOURCE_MASK(64),
+ .read = timebase_read,
};
#define DECREMENTER_MAX 0x7fffffff
@@ -106,12 +106,12 @@ static void decrementer_set_mode(enum cl
struct clock_event_device *dev);
static struct clock_event_device decrementer_clockevent = {
- .name = "decrementer",
- .rating = 200,
- .irq = 0,
- .set_next_event = decrementer_set_next_event,
- .set_mode = decrementer_set_mode,
- .features = CLOCK_EVT_FEAT_ONESHOT,
+ .name = "decrementer",
+ .rating = 200,
+ .irq = 0,
+ .set_next_event = decrementer_set_next_event,
+ .set_mode = decrementer_set_mode,
+ .features = CLOCK_EVT_FEAT_ONESHOT,
};
static DEFINE_PER_CPU(struct clock_event_device, decrementers);
@@ -430,7 +430,7 @@ EXPORT_SYMBOL(profile_pc);
/*
* This function recalibrates the timebase based on the 49-bit time-of-day
* value in the Titan chip. The Titan is much more accurate than the value
- * returned by the service processor for the timebase frequency.
+ * returned by the service processor for the timebase frequency.
*/
static int __init iSeries_tb_recal(void)
@@ -628,9 +628,9 @@ static void generic_suspend_disable_irqs
* with suspending.
*/
- set_dec(0x7fffffff);
+ set_dec(DECREMENTER_MAX);
local_irq_disable();
- set_dec(0x7fffffff);
+ set_dec(DECREMENTER_MAX);
}
static void generic_suspend_enable_irqs(void)
@@ -965,10 +965,10 @@ void __init time_init(void)
boot_tb = get_tb_or_rtc();
/* If platform provided a timezone (pmac), we correct the time */
- if (timezone_offset) {
+ if (timezone_offset) {
sys_tz.tz_minuteswest = -timezone_offset / 60;
sys_tz.tz_dsttime = 0;
- }
+ }
vdso_data->tb_update_count = 0;
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
^ permalink raw reply [flat|nested] 8+ messages in thread