* published by the Free Software Foundation.
*/
-#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/sched.h>
+#include <linux/clocksource.h>
#include <asm/system.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
+#include <asm/arch/pxa-regs.h>
static inline unsigned long pxa_get_rtc_time(void)
return 0;
}
-/* IRQs are disabled before entering here from do_gettimeofday() */
-static unsigned long pxa_gettimeoffset (void)
-{
- long ticks_to_match, elapsed, usec;
-
- /* Get ticks before next timer match */
- ticks_to_match = OSMR0 - OSCR;
-
- /* We need elapsed ticks since last match */
- elapsed = LATCH - ticks_to_match;
-
- /* don't get fooled by the workaround in pxa_timer_interrupt() */
- if (elapsed <= 0)
- return 0;
-
- /* Now convert them to usec */
- usec = (unsigned long)(elapsed * (tick_nsec / 1000))/LATCH;
-
- return usec;
-}
+#ifdef CONFIG_NO_IDLE_HZ
+static unsigned long initial_match;
+static int match_posponed;
+#endif
static irqreturn_t
-pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+pxa_timer_interrupt(int irq, void *dev_id)
{
int next_match;
+ write_seqlock(&xtime_lock);
+
+#ifdef CONFIG_NO_IDLE_HZ
+ if (match_posponed) {
+ match_posponed = 0;
+ OSMR0 = initial_match;
+ }
+#endif
+
/* Loop until we get ahead of the free running timer.
* This ensures an exact clock tick count and time accuracy.
- * IRQs are disabled inside the loop to ensure coherence between
- * lost_ticks (updated in do_timer()) and the match reg value, so we
- * can use do_gettimeofday() from interrupt handlers.
+ * Since IRQs are disabled at this point, coherence between
+ * lost_ticks(updated in do_timer()) and the match reg value is
+ * ensured, hence we can use do_gettimeofday() from interrupt
+ * handlers.
*
* HACK ALERT: it seems that the PXA timer regs aren't updated right
* away in all cases when a write occurs. We therefore compare with
* exactly one tick period which should be a pretty rare event.
*/
do {
- timer_tick(regs);
+ timer_tick();
OSSR = OSSR_M0; /* Clear match on timer 0 */
next_match = (OSMR0 += LATCH);
} while( (signed long)(next_match - OSCR) <= 8 );
+ write_sequnlock(&xtime_lock);
+
return IRQ_HANDLED;
}
static struct irqaction pxa_timer_irq = {
.name = "PXA Timer Tick",
- .flags = SA_INTERRUPT,
- .handler = pxa_timer_interrupt
+ .flags = IRQF_DISABLED | IRQF_TIMER,
+ .handler = pxa_timer_interrupt,
+};
+
+static cycle_t pxa_get_cycles(void)
+{
+ return OSCR;
+}
+
+static struct clocksource clocksource_pxa = {
+ .name = "pxa_timer",
+ .rating = 200,
+ .read = pxa_get_cycles,
+ .mask = CLOCKSOURCE_MASK(32),
+ .shift = 20,
+ .is_continuous = 1,
};
-void __init pxa_init_time(void)
+static void __init pxa_timer_init(void)
{
struct timespec tv;
+ unsigned long flags;
- gettimeoffset = pxa_gettimeoffset;
set_rtc = pxa_set_rtc;
tv.tv_nsec = 0;
tv.tv_sec = pxa_get_rtc_time();
do_settimeofday(&tv);
- OSMR0 = 0; /* set initial match at 0 */
+ OIER = 0; /* disable any timer interrupts */
OSSR = 0xf; /* clear status on all timers */
setup_irq(IRQ_OST0, &pxa_timer_irq);
- OIER |= OIER_E0; /* enable match on timer 0 to cause interrupts */
- OSCR = 0; /* initialize free-running timer, force first match */
+ local_irq_save(flags);
+ OIER = OIER_E0; /* enable match on timer 0 to cause interrupts */
+ OSMR0 = OSCR + LATCH; /* set initial match */
+ local_irq_restore(flags);
+
+ /*
+ * OSCR runs continuously on PXA and is not written to,
+ * so we can use it as clock source directly.
+ */
+ clocksource_pxa.mult =
+ clocksource_hz2mult(CLOCK_TICK_RATE, clocksource_pxa.shift);
+ clocksource_register(&clocksource_pxa);
+}
+
+#ifdef CONFIG_NO_IDLE_HZ
+static int pxa_dyn_tick_enable_disable(void)
+{
+ /* nothing to do */
+ return 0;
+}
+
+static void pxa_dyn_tick_reprogram(unsigned long ticks)
+{
+ if (ticks > 1) {
+ initial_match = OSMR0;
+ OSMR0 = initial_match + ticks * LATCH;
+ match_posponed = 1;
+ }
+}
+
+static irqreturn_t
+pxa_dyn_tick_handler(int irq, void *dev_id)
+{
+ if (match_posponed) {
+ match_posponed = 0;
+ OSMR0 = initial_match;
+ if ( (signed long)(initial_match - OSCR) <= 8 )
+ return pxa_timer_interrupt(irq, dev_id);
+ }
+ return IRQ_NONE;
}
+static struct dyn_tick_timer pxa_dyn_tick = {
+ .enable = pxa_dyn_tick_enable_disable,
+ .disable = pxa_dyn_tick_enable_disable,
+ .reprogram = pxa_dyn_tick_reprogram,
+ .handler = pxa_dyn_tick_handler,
+};
+#endif
+
+#ifdef CONFIG_PM
+static unsigned long osmr[4], oier;
+
+static void pxa_timer_suspend(void)
+{
+ osmr[0] = OSMR0;
+ osmr[1] = OSMR1;
+ osmr[2] = OSMR2;
+ osmr[3] = OSMR3;
+ oier = OIER;
+}
+
+static void pxa_timer_resume(void)
+{
+ OSMR0 = osmr[0];
+ OSMR1 = osmr[1];
+ OSMR2 = osmr[2];
+ OSMR3 = osmr[3];
+ OIER = oier;
+
+ /*
+ * OSMR0 is the system timer: make sure OSCR is sufficiently behind
+ */
+ OSCR = OSMR0 - LATCH;
+}
+#else
+#define pxa_timer_suspend NULL
+#define pxa_timer_resume NULL
+#endif
+
+struct sys_timer pxa_timer = {
+ .init = pxa_timer_init,
+ .suspend = pxa_timer_suspend,
+ .resume = pxa_timer_resume,
+#ifdef CONFIG_NO_IDLE_HZ
+ .dyn_tick = &pxa_dyn_tick,
+#endif
+};
git://git.onelab.eu / linux-2.6.git / blobdiff