Commit dc548fbb authored by Russell King's avatar Russell King
Browse files

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



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

Tested-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ec05aa13

arch/arm/Kconfig

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

arch/arm/plat-omap/counter_32k.c

+22 −2
Original line number Diff line number Diff line
@@ -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;

}