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Commit cef5975d authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Russell King
Browse files

[ARM] 4592/1: ns9xxx: clocksource driver 



Signed-off-by: default avatarUwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent f02e5795

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -319,6 +319,7 @@ config ARCH_KS8695 
config ARCH_NS9XXX

	bool "NetSilicon NS9xxx"

	select GENERIC_GPIO

	select GENERIC_TIME

	help

	  Say Y here if you intend to run this kernel on a NetSilicon NS9xxx

	  System.

arch/arm/mach-ns9xxx/time.c

+42 −26
Original line number Diff line number Diff line
@@ -11,6 +11,9 @@ 
#include <linux/jiffies.h>

#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/stringify.h>

#include <linux/clocksource.h>



#include <asm/arch-ns9xxx/regs-sys.h>

#include <asm/arch-ns9xxx/clock.h>

#include <asm/arch-ns9xxx/irqs.h>
@@ -18,8 +21,7 @@ 
#include "generic.h"



#define TIMERCLOCKSELECT 64



static u32 usecs_per_tick;

#define TIMER_CLOCKSOURCE 1



static irqreturn_t

ns9xxx_timer_interrupt(int irq, void *dev_id)
@@ -45,39 +47,30 @@ ns9xxx_timer_interrupt(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



static unsigned long ns9xxx_timer_gettimeoffset(void)

{

	/* return the microseconds which have passed since the last interrupt

	 * was _serviced_.  That is, if an interrupt is pending or the counter

	 * reloads, return one period more. */



	u32 counter1 = SYS_TR(0);

	int pending = SYS_ISR & (1 << IRQ_TIMER0);

	u32 counter2 = SYS_TR(0);

	u32 elapsed;



	if (pending || counter2 > counter1)

		elapsed = 2 * SYS_TRC(0) - counter2;

	else

		elapsed = SYS_TRC(0) - counter1;



	return (elapsed * usecs_per_tick) >> 16;



}



static struct irqaction ns9xxx_timer_irq = {

	.name = "NS9xxx Timer Tick",

	.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,

	.handler = ns9xxx_timer_interrupt,

};



static cycle_t ns9xxx_clocksource_read(void)

{

	return SYS_TR(TIMER_CLOCKSOURCE);

}



static struct clocksource ns9xxx_clocksource = {

	.name	= "ns9xxx-timer" __stringify(TIMER_CLOCKSOURCE),

	.rating	= 300,

	.read	= ns9xxx_clocksource_read,

	.mask	= CLOCKSOURCE_MASK(32),

	.shift	= 20,

	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,

};



static void __init ns9xxx_timer_init(void)

{

	int tc;



	usecs_per_tick =

		SH_DIV(1000000 * TIMERCLOCKSELECT, ns9xxx_cpuclock(), 16);



	/* disable timer */

	if ((tc = SYS_TC(0)) & SYS_TCx_TEN)

		SYS_TC(0) = tc & ~SYS_TCx_TEN;
@@ -94,9 +87,32 @@ static void __init ns9xxx_timer_init(void) 
	SYS_TC(0) = tc;



	setup_irq(IRQ_TIMER0, &ns9xxx_timer_irq);



	tc = SYS_TC(TIMER_CLOCKSOURCE);

	if (REGGET(tc, SYS_TCx, TEN)) {

		REGSET(tc, SYS_TCx, TEN, DIS);

		SYS_TC(TIMER_CLOCKSOURCE) = tc;

	}



	SYS_TRC(TIMER_CLOCKSOURCE) = 0;



	REGSET(tc, SYS_TCx, TEN, EN);

	REGSET(tc, SYS_TCx, TDBG, STOP);

	REGSET(tc, SYS_TCx, TLCS, CPU);

	REGSET(tc, SYS_TCx, TM, IEE);

	REGSET(tc, SYS_TCx, INTS, DIS);

	REGSET(tc, SYS_TCx, UDS, UP);

	REGSET(tc, SYS_TCx, TSZ, 32);

	REGSET(tc, SYS_TCx, REN, EN);



	SYS_TC(TIMER_CLOCKSOURCE) = tc;



	ns9xxx_clocksource.mult = clocksource_hz2mult(ns9xxx_cpuclock(),

			ns9xxx_clocksource.shift);



	clocksource_register(&ns9xxx_clocksource);

}



struct sys_timer ns9xxx_timer = {

	.init = ns9xxx_timer_init,

	.offset = ns9xxx_timer_gettimeoffset,

};