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Commit 8c414ff3 authored by Russell King's avatar Russell King
Browse files

clocksource: convert footbridge to generic i8253 clocksource 



Convert the footbridge isa-timer code to use generic i8253 clocksource.

Acked-by: default avatarJohn Stultz <john.stultz@linaro.org>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 89c0b8e2

arch/arm/include/asm/i8253.h

0 → 100644
+15 −0
Original line number Diff line number Diff line 
#ifndef __ASMARM_I8253_H

#define __ASMARM_I8253_H



/* i8253A PIT registers */

#define PIT_MODE	0x43

#define PIT_CH0		0x40



#define PIT_LATCH	((PIT_TICK_RATE + HZ / 2) / HZ)



extern raw_spinlock_t i8253_lock;



#define outb_pit	outb_p

#define inb_pit		inb_p



#endif

arch/arm/mach-footbridge/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ menu "Footbridge Implementations" 


config ARCH_CATS

	bool "CATS"

	select CLKSRC_I8253

	select FOOTBRIDGE_HOST

	select ISA

	select ISA_DMA
@@ -59,6 +60,7 @@ config ARCH_EBSA285_HOST 


config ARCH_NETWINDER

	bool "NetWinder"

	select CLKSRC_I8253

	select FOOTBRIDGE_HOST

	select ISA

	select ISA_DMA

arch/arm/mach-footbridge/isa-timer.c

+4 −41
Original line number Diff line number Diff line
@@ -10,53 +10,16 @@ 
#include <linux/interrupt.h>

#include <linux/irq.h>

#include <linux/io.h>

#include <linux/spinlock.h>

#include <linux/timex.h>



#include <asm/irq.h>



#include <asm/i8253.h>

#include <asm/mach/time.h>



#include "common.h"



#define PIT_MODE	0x43

#define PIT_CH0		0x40



#define PIT_LATCH	((PIT_TICK_RATE + HZ / 2) / HZ)



static cycle_t pit_read(struct clocksource *cs)

{

	unsigned long flags;

	static int old_count;

	static u32 old_jifs;

	int count;

	u32 jifs;



	raw_local_irq_save(flags);



	jifs = jiffies;

	outb_p(0x00, PIT_MODE);		/* latch the count */

	count = inb_p(PIT_CH0);		/* read the latched count */

	count |= inb_p(PIT_CH0) << 8;



	if (count > old_count && jifs == old_jifs)

		count = old_count;



	old_count = count;

	old_jifs = jifs;



	raw_local_irq_restore(flags);



	count = (PIT_LATCH - 1) - count;



	return (cycle_t)(jifs * PIT_LATCH) + count;

}



static struct clocksource pit_cs = {

	.name		= "pit",

	.rating		= 110,

	.read		= pit_read,

	.mask		= CLOCKSOURCE_MASK(32),

};

DEFINE_RAW_SPINLOCK(i8253_lock);



static void pit_set_mode(enum clock_event_mode mode,

	struct clock_event_device *evt)
@@ -121,7 +84,7 @@ static void __init isa_timer_init(void) 
	pit_ce.max_delta_ns = clockevent_delta2ns(0x7fff, &pit_ce);

	pit_ce.min_delta_ns = clockevent_delta2ns(0x000f, &pit_ce);



	clocksource_register_hz(&pit_cs, PIT_TICK_RATE);

	clocksource_i8253_init();



	setup_irq(pit_ce.irq, &pit_timer_irq);

	clockevents_register_device(&pit_ce);

include/linux/clocksource.h

+2 −0
Original line number Diff line number Diff line
@@ -341,4 +341,6 @@ static inline void update_vsyscall_tz(void) 


extern void timekeeping_notify(struct clocksource *clock);



extern int clocksource_i8253_init(void);



#endif /* _LINUX_CLOCKSOURCE_H */