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ARM: mmp: convert sched_clock() to use new infrastructure

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Convert mmp to use the new sched_clock() infrastructure for extending
32bit counters to full 64-bit nanoseconds.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2010-12-15 21:46:48 +00:00
parent 5b0d495c06
commit 28bb7bc61a
2 changed files with 12 additions and 21 deletions
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1
arch/arm/Kconfig
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@ -513,6 +513,7 @@ config ARCH_MMP
select ARCH_REQUIRE_GPIOLIB
select COMMON_CLKDEV
select GENERIC_CLOCKEVENTS
select HAVE_SCHED_CLOCK
select TICK_ONESHOT
select PLAT_PXA
select SPARSE_IRQ

32
arch/arm/mach-mmp/time.c
View File

@ -26,8 +26,8 @@
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/cnt32_to_63.h>
#include <asm/sched_clock.h>
#include <mach/addr-map.h>
#include <mach/regs-timers.h>
#include <mach/regs-apbc.h>
@ -42,23 +42,7 @@
#define MAX_DELTA (0xfffffffe)
#define MIN_DELTA (16)
#define TCR2NS_SCALE_FACTOR 10
static unsigned long tcr2ns_scale;
static void __init set_tcr2ns_scale(unsigned long tcr_rate)
{
unsigned long long v = 1000000000ULL << TCR2NS_SCALE_FACTOR;
do_div(v, tcr_rate);
tcr2ns_scale = v;
/*
* We want an even value to automatically clear the top bit
* returned by cnt32_to_63() without an additional run time
* instruction. So if the LSB is 1 then round it up.
*/
if (tcr2ns_scale & 1)
tcr2ns_scale++;
}
static DEFINE_CLOCK_DATA(cd);
/*
* FIXME: the timer needs some delay to stablize the counter capture
@ -77,8 +61,14 @@ static inline uint32_t timer_read(void)
unsigned long long notrace sched_clock(void)
{
unsigned long long v = cnt32_to_63(timer_read());
return (v * tcr2ns_scale) >> TCR2NS_SCALE_FACTOR;
u32 cyc = timer_read();
return cyc_to_sched_clock(&cd, cyc, (u32)~0);
}
static void notrace mmp_update_sched_clock(void)
{
u32 cyc = timer_read();
update_sched_clock(&cd, cyc, (u32)~0);
}
static irqreturn_t timer_interrupt(int irq, void *dev_id)
@ -185,7 +175,7 @@ void __init timer_init(int irq)
{
timer_config();
set_tcr2ns_scale(CLOCK_TICK_RATE);
init_sched_clock(&cd, mmp_update_sched_clock, 32, CLOCK_TICK_RATE);
ckevt.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt.shift);
ckevt.max_delta_ns = clockevent_delta2ns(MAX_DELTA, &ckevt);