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Commit 5094b92f authored by Russell King's avatar Russell King
Browse files

ARM: sa1100: convert sched_clock() to use new infrastructure 



Convert sa1100 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 7ce83018

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -642,6 +642,7 @@ config ARCH_SA1100 
	select CPU_FREQ

	select GENERIC_CLOCKEVENTS

	select HAVE_CLK

	select HAVE_SCHED_CLOCK

	select TICK_ONESHOT

	select ARCH_REQUIRE_GPIOLIB

	help

arch/arm/mach-sa1100/generic.c

+0 −23
Original line number Diff line number Diff line
@@ -16,9 +16,7 @@ 
#include <linux/pm.h>

#include <linux/cpufreq.h>

#include <linux/ioport.h>

#include <linux/sched.h>	/* just for sched_clock() - funny that */

#include <linux/platform_device.h>

#include <linux/cnt32_to_63.h>



#include <asm/div64.h>

#include <mach/hardware.h>
@@ -109,27 +107,6 @@ unsigned int sa11x0_getspeed(unsigned int cpu) 
	return cclk_frequency_100khz[PPCR & 0xf] * 100;

}



/*

 * This is the SA11x0 sched_clock implementation.  This has

 * a resolution of 271ns, and a maximum value of 32025597s (370 days).

 *

 * The return value is guaranteed to be monotonic in that range as

 * long as there is always less than 582 seconds between successive

 * calls to this function.

 *

 *  ( * 1E9 / 3686400 => * 78125 / 288)

 */

unsigned long long notrace sched_clock(void)

{

	unsigned long long v = cnt32_to_63(OSCR);



	/* the <<1 gets rid of the cnt_32_to_63 top bit saving on a bic insn */

	v *= 78125<<1;

	do_div(v, 288<<1);



	return v;

}



/*

 * Default power-off for SA1100

 */

arch/arm/mach-sa1100/time.c

+30 −0
Original line number Diff line number Diff line
@@ -12,12 +12,39 @@ 
#include <linux/errno.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/sched.h>	/* just for sched_clock() - funny that */

#include <linux/timex.h>

#include <linux/clockchips.h>



#include <asm/mach/time.h>

#include <asm/sched_clock.h>

#include <mach/hardware.h>



/*

 * This is the SA11x0 sched_clock implementation.

 */

static DEFINE_CLOCK_DATA(cd);



/*

 * Constants generated by clocks_calc_mult_shift(m, s, 3.6864MHz,

 * NSEC_PER_SEC, 60).

 * This gives a resolution of about 271ns and a wrap period of about 19min.

 */

#define SC_MULT		2275555556u

#define SC_SHIFT	23



unsigned long long notrace sched_clock(void)

{

	u32 cyc = OSCR;

	return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);

}



static void notrace sa1100_update_sched_clock(void)

{

	u32 cyc = OSCR;

	update_sched_clock(&cd, cyc, (u32)~0);

}



#define MIN_OSCR_DELTA 2



static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id)
@@ -96,6 +123,9 @@ static void __init sa1100_timer_init(void) 
	OIER = 0;		/* disable any timer interrupts */

	OSSR = 0xf;		/* clear status on all timers */



	init_fixed_sched_clock(&cd, sa1100_update_sched_clock, 32,

			       3686400, SC_MULT, SC_SHIFT);



	ckevt_sa1100_osmr0.mult =

		div_sc(3686400, NSEC_PER_SEC, ckevt_sa1100_osmr0.shift);

	ckevt_sa1100_osmr0.max_delta_ns =