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Commit 28bb7bc6 authored by Russell King's avatar Russell King
Browse files

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



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

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 5b0d495c

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/arm/mach-mmp/time.c

+11 −21
Original line number Diff line number Diff line
@@ -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);