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[ARM] 4592/1: ns9xxx: clocksource driver

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Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Uwe Kleine-König 2007-09-30 20:35:48 +01:00 committed by Russell King
parent f02e579558
commit cef5975d45
2 changed files with 43 additions and 26 deletions
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1
arch/arm/Kconfig
View file

@ -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.

68
arch/arm/mach-ns9xxx/time.c
View file

@ -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,
};