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Diffstat (limited to 'arch/arm/mach-at91rm9200/time.c')
-rw-r--r--arch/arm/mach-at91rm9200/time.c57
1 files changed, 36 insertions, 21 deletions
diff --git a/arch/arm/mach-at91rm9200/time.c b/arch/arm/mach-at91rm9200/time.c
index 7ffcf443b99..fc2d7d5e463 100644
--- a/arch/arm/mach-at91rm9200/time.c
+++ b/arch/arm/mach-at91rm9200/time.c
@@ -31,6 +31,8 @@
#include <asm/irq.h>
#include <asm/mach/time.h>
+static unsigned long last_crtr;
+
/*
* The ST_CRTR is updated asynchronously to the master clock. It is therefore
* necessary to read it twice (with the same value) to ensure accuracy.
@@ -56,7 +58,7 @@ static unsigned long at91rm9200_gettimeoffset(void)
{
unsigned long elapsed;
- elapsed = (read_CRTR() - at91_sys_read(AT91_ST_RTAR)) & AT91_ST_ALMV;
+ elapsed = (read_CRTR() - last_crtr) & AT91_ST_ALMV;
return (unsigned long)(elapsed * (tick_nsec / 1000)) / LATCH;
}
@@ -66,15 +68,12 @@ static unsigned long at91rm9200_gettimeoffset(void)
*/
static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
- unsigned long rtar;
-
if (at91_sys_read(AT91_ST_SR) & AT91_ST_PITS) { /* This is a shared interrupt */
write_seqlock(&xtime_lock);
- while (((read_CRTR() - at91_sys_read(AT91_ST_RTAR)) & AT91_ST_ALMV) >= LATCH) {
+ while (((read_CRTR() - last_crtr) & AT91_ST_ALMV) >= LATCH) {
timer_tick(regs);
- rtar = (at91_sys_read(AT91_ST_RTAR) + LATCH) & AT91_ST_ALMV;
- at91_sys_write(AT91_ST_RTAR, rtar);
+ last_crtr = (last_crtr + LATCH) & AT91_ST_ALMV;
}
write_sequnlock(&xtime_lock);
@@ -87,10 +86,24 @@ static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id, struct pt_r
static struct irqaction at91rm9200_timer_irq = {
.name = "at91_tick",
- .flags = SA_SHIRQ | SA_INTERRUPT,
+ .flags = SA_SHIRQ | SA_INTERRUPT | SA_TIMER,
.handler = at91rm9200_timer_interrupt
};
+void at91rm9200_timer_reset(void)
+{
+ last_crtr = 0;
+
+ /* Real time counter incremented every 30.51758 microseconds */
+ at91_sys_write(AT91_ST_RTMR, 1);
+
+ /* Set Period Interval timer */
+ at91_sys_write(AT91_ST_PIMR, LATCH);
+
+ /* Enable Period Interval Timer interrupt */
+ at91_sys_write(AT91_ST_IER, AT91_ST_PITS);
+}
+
/*
* Set up timer interrupt.
*/
@@ -100,28 +113,30 @@ void __init at91rm9200_timer_init(void)
at91_sys_write(AT91_ST_IDR, AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS);
(void) at91_sys_read(AT91_ST_SR); /* Clear any pending interrupts */
- /*
- * Make IRQs happen for the system timer.
- */
+ /* Make IRQs happen for the system timer */
setup_irq(AT91_ID_SYS, &at91rm9200_timer_irq);
- /* Set initial alarm to 0 */
- at91_sys_write(AT91_ST_RTAR, 0);
-
- /* Real time counter incremented every 30.51758 microseconds */
- at91_sys_write(AT91_ST_RTMR, 1);
-
- /* Set Period Interval timer */
- at91_sys_write(AT91_ST_PIMR, LATCH);
-
/* Change the kernel's 'tick' value to 10009 usec. (the default is 10000) */
tick_usec = (LATCH * 1000000) / CLOCK_TICK_RATE;
- /* Enable Period Interval Timer interrupt */
- at91_sys_write(AT91_ST_IER, AT91_ST_PITS);
+ /* Initialize and enable the timer interrupt */
+ at91rm9200_timer_reset();
+}
+
+#ifdef CONFIG_PM
+static void at91rm9200_timer_suspend(void)
+{
+ /* disable Period Interval Timer interrupt */
+ at91_sys_write(AT91_ST_IDR, AT91_ST_PITS);
}
+#else
+#define at91rm9200_timer_suspend NULL
+#endif
struct sys_timer at91rm9200_timer = {
.init = at91rm9200_timer_init,
.offset = at91rm9200_gettimeoffset,
+ .suspend = at91rm9200_timer_suspend,
+ .resume = at91rm9200_timer_reset,
};
+