Commit f06a1624 authored by Russell King's avatar Russell King
Browse files

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



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

Acked-by: default avatarNicolas Pitre <nico@fluxnic.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent dc548fbb

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -997,6 +997,7 @@ config PLAT_IOP 


config PLAT_ORION

	bool

	select HAVE_SCHED_CLOCK



config PLAT_PXA

	bool

arch/arm/plat-orion/time.c

+9 −35
Original line number Diff line number Diff line
@@ -13,11 +13,11 @@ 


#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/cnt32_to_63.h>

#include <linux/timer.h>

#include <linux/clockchips.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <asm/sched_clock.h>

#include <asm/mach/time.h>

#include <mach/bridge-regs.h>

#include <mach/hardware.h>
@@ -44,52 +44,26 @@ static u32 ticks_per_jiffy; 


/*

 * Orion's sched_clock implementation. It has a resolution of

 * at least 7.5ns (133MHz TCLK) and a maximum value of 834 days.

 *

 * Because the hardware timer period is quite short (21 secs if

 * 200MHz TCLK) and because cnt32_to_63() needs to be called at

 * least once per half period to work properly, a kernel timer is

 * set up to ensure this requirement is always met.

 * at least 7.5ns (133MHz TCLK).

 */

#define TCLK2NS_SCALE_FACTOR 8



static unsigned long tclk2ns_scale;

static DEFINE_CLOCK_DATA(cd);



unsigned long long notrace sched_clock(void)

{

	unsigned long long v = cnt32_to_63(0xffffffff - readl(TIMER0_VAL));

	return (v * tclk2ns_scale) >> TCLK2NS_SCALE_FACTOR;

	u32 cyc = 0xffffffff - readl(TIMER0_VAL);

	return cyc_to_sched_clock(&cd, cyc, (u32)~0);

}



static struct timer_list cnt32_to_63_keepwarm_timer;



static void cnt32_to_63_keepwarm(unsigned long data)

static void notrace orion_update_sched_clock(void)

{

	mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + data));

	(void) sched_clock();

	u32 cyc = 0xffffffff - readl(TIMER0_VAL);

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

}



static void __init setup_sched_clock(unsigned long tclk)

{

	unsigned long long v;

	unsigned long data;



	v = NSEC_PER_SEC;

	v <<= TCLK2NS_SCALE_FACTOR;

	v += tclk/2;

	do_div(v, tclk);

	/*

	 * 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 (v & 1)

		v++;

	tclk2ns_scale = v;



	data = (0xffffffffUL / tclk / 2 - 2) * HZ;

	setup_timer(&cnt32_to_63_keepwarm_timer, cnt32_to_63_keepwarm, data);

	mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + data));

	init_sched_clock(&cd, orion_update_sched_clock, 32, tclk);

}



/*