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

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

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2010-12-15 21:53:51 +00:00
parent ec05aa1399
commit dc548fbbd2
2 changed files with 23 additions and 2 deletions
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1
arch/arm/Kconfig
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@ -839,6 +839,7 @@ config ARCH_OMAP
select ARCH_REQUIRE_GPIOLIB
select ARCH_HAS_CPUFREQ
select GENERIC_CLOCKEVENTS
select HAVE_SCHED_CLOCK
select ARCH_HAS_HOLES_MEMORYMODEL
help
Support for TI's OMAP platform (OMAP1/2/3/4).

24
arch/arm/plat-omap/counter_32k.c
View file

@ -18,6 +18,8 @@
#include <linux/io.h>
#include <linux/sched.h>
#include <asm/sched_clock.h>
#include <plat/common.h>
#include <plat/board.h>
@ -110,10 +112,25 @@ static struct clocksource clocksource_32k = {
* Returns current time from boot in nsecs. It's OK for this to wrap
* around for now, as it's just a relative time stamp.
*/
static DEFINE_CLOCK_DATA(cd);
/*
* Constants generated by clocks_calc_mult_shift(m, s, 32768, NSEC_PER_SEC, 60).
* This gives a resolution of about 30us and a wrap period of about 36hrs.
*/
#define SC_MULT 4000000000u
#define SC_SHIFT 17
unsigned long long notrace sched_clock(void)
{
return clocksource_cyc2ns(clocksource_32k.read(&clocksource_32k),
clocksource_32k.mult, clocksource_32k.shift);
u32 cyc = clocksource_32k.read(&clocksource_32k);
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
}
static void notrace omap_update_sched_clock(void)
{
u32 cyc = clocksource_32k.read(&clocksource_32k);
update_sched_clock(&cd, cyc, (u32)~0);
}
/**
@ -171,6 +188,9 @@ static int __init omap_init_clocksource_32k(void)
if (clocksource_register_hz(&clocksource_32k, 32768))
printk(err, clocksource_32k.name);
init_fixed_sched_clock(&cd, omap_update_sched_clock, 32,
32768, SC_MULT, SC_SHIFT);
}
return 0;
}