[ARM] 4262/1: OMAP: clocksource and clockevent support
Update OMAP1 to enable support for hrtimers and dynticks by using new clocksource and clockevent infrastructure.
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/plat-omap/timer32k.c b/arch/arm/plat-omap/timer32k.c
index 2653106..114f871 100644
--- a/arch/arm/plat-omap/timer32k.c
+++ b/arch/arm/plat-omap/timer32k.c
@@ -42,6 +42,8 @@
#include <linux/spinlock.h>
#include <linux/err.h>
#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <asm/system.h>
#include <asm/hardware.h>
@@ -80,13 +82,13 @@
#define OMAP1_32K_TIMER_TVR 0x00
#define OMAP1_32K_TIMER_TCR 0x04
-#define OMAP_32K_TICKS_PER_HZ (32768 / HZ)
+#define OMAP_32K_TICKS_PER_SEC (32768)
/*
* TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1
* so with HZ = 128, TVR = 255.
*/
-#define OMAP_32K_TIMER_TICK_PERIOD ((32768 / HZ) - 1)
+#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \
(((nr_jiffies) * (clock_rate)) / HZ)
@@ -142,6 +144,28 @@
#endif
+static void omap_32k_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_PERIODIC:
+ omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ omap_32k_timer_stop();
+ break;
+ }
+}
+
+static struct clock_event_device clockevent_32k_timer = {
+ .name = "32k-timer",
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+ .shift = 32,
+ .set_mode = omap_32k_timer_set_mode,
+};
+
/*
* The 32KHz synchronized timer is an additional timer on 16xx.
* It is always running.
@@ -171,15 +195,6 @@
static unsigned long omap_32k_last_tick = 0;
/*
- * Returns elapsed usecs since last 32k timer interrupt
- */
-static unsigned long omap_32k_timer_gettimeoffset(void)
-{
- unsigned long now = omap_32k_sync_timer_read();
- return omap_32k_ticks_to_usecs(now - omap_32k_last_tick);
-}
-
-/*
* Returns current time from boot in nsecs. It's OK for this to wrap
* around for now, as it's just a relative time stamp.
*/
@@ -188,95 +203,16 @@
return omap_32k_ticks_to_nsecs(omap_32k_sync_timer_read());
}
-/*
- * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this
- * function is also called from other interrupts to remove latency
- * issues with dynamic tick. In the dynamic tick case, we need to lock
- * with irqsave.
- */
-static inline irqreturn_t _omap_32k_timer_interrupt(int irq, void *dev_id)
-{
- unsigned long now;
-
- omap_32k_timer_ack_irq();
- now = omap_32k_sync_timer_read();
-
- while ((signed long)(now - omap_32k_last_tick)
- >= OMAP_32K_TICKS_PER_HZ) {
- omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ;
- timer_tick();
- }
-
- /* Restart timer so we don't drift off due to modulo or dynamic tick.
- * By default we program the next timer to be continuous to avoid
- * latencies during high system load. During dynamic tick operation the
- * continuous timer can be overridden from pm_idle to be longer.
- */
- omap_32k_timer_start(omap_32k_last_tick + OMAP_32K_TICKS_PER_HZ - now);
-
- return IRQ_HANDLED;
-}
-
-static irqreturn_t omap_32k_timer_handler(int irq, void *dev_id)
-{
- return _omap_32k_timer_interrupt(irq, dev_id);
-}
-
static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id)
{
- unsigned long flags;
+ struct clock_event_device *evt = &clockevent_32k_timer;
+ omap_32k_timer_ack_irq();
- write_seqlock_irqsave(&xtime_lock, flags);
- _omap_32k_timer_interrupt(irq, dev_id);
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ evt->event_handler(evt);
return IRQ_HANDLED;
}
-#ifdef CONFIG_NO_IDLE_HZ
-/*
- * Programs the next timer interrupt needed. Called when dynamic tick is
- * enabled, and to reprogram the ticks to skip from pm_idle. Note that
- * we can keep the timer continuous, and don't need to set it to run in
- * one-shot mode. This is because the timer will get reprogrammed again
- * after next interrupt.
- */
-void omap_32k_timer_reprogram(unsigned long next_tick)
-{
- unsigned long ticks = JIFFIES_TO_HW_TICKS(next_tick, 32768) + 1;
- unsigned long now = omap_32k_sync_timer_read();
- unsigned long idled = now - omap_32k_last_tick;
-
- if (idled + 1 < ticks)
- ticks -= idled;
- else
- ticks = 1;
- omap_32k_timer_start(ticks);
-}
-
-static struct irqaction omap_32k_timer_irq;
-extern struct timer_update_handler timer_update;
-
-static int omap_32k_timer_enable_dyn_tick(void)
-{
- /* No need to reprogram timer, just use the next interrupt */
- return 0;
-}
-
-static int omap_32k_timer_disable_dyn_tick(void)
-{
- omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
- return 0;
-}
-
-static struct dyn_tick_timer omap_dyn_tick_timer = {
- .enable = omap_32k_timer_enable_dyn_tick,
- .disable = omap_32k_timer_disable_dyn_tick,
- .reprogram = omap_32k_timer_reprogram,
- .handler = omap_32k_timer_handler,
-};
-#endif /* CONFIG_NO_IDLE_HZ */
-
static struct irqaction omap_32k_timer_irq = {
.name = "32KHz timer",
.flags = IRQF_DISABLED | IRQF_TIMER,
@@ -285,13 +221,8 @@
static __init void omap_init_32k_timer(void)
{
-#ifdef CONFIG_NO_IDLE_HZ
- omap_timer.dyn_tick = &omap_dyn_tick_timer;
-#endif
-
if (cpu_class_is_omap1())
setup_irq(INT_OS_TIMER, &omap_32k_timer_irq);
- omap_timer.offset = omap_32k_timer_gettimeoffset;
omap_32k_last_tick = omap_32k_sync_timer_read();
#ifdef CONFIG_ARCH_OMAP2
@@ -308,7 +239,16 @@
}
#endif
- omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
+ clockevent_32k_timer.mult = div_sc(OMAP_32K_TICKS_PER_SEC,
+ NSEC_PER_SEC,
+ clockevent_32k_timer.shift);
+ clockevent_32k_timer.max_delta_ns =
+ clockevent_delta2ns(0xfffffffe, &clockevent_32k_timer);
+ clockevent_32k_timer.min_delta_ns =
+ clockevent_delta2ns(1, &clockevent_32k_timer);
+
+ clockevent_32k_timer.cpumask = cpumask_of_cpu(0);
+ clockevents_register_device(&clockevent_32k_timer);
}
/*
@@ -326,5 +266,4 @@
struct sys_timer omap_timer = {
.init = omap_timer_init,
- .offset = NULL, /* Initialized later */
};