#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>
#define OMAP1_32K_TIMER_TVR 0x00
#define OMAP1_32K_TIMER_TCR 0x04
-#define OMAP_32K_TICKS_PER_SEC (32768)
+#define OMAP_32K_TICKS_PER_HZ (32768 / HZ)
/*
* TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1
* so with HZ = 128, TVR = 255.
*/
-#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
+#define OMAP_32K_TIMER_TICK_PERIOD ((32768 / HZ) - 1)
#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \
(((nr_jiffies) * (clock_rate)) / HZ)
#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.
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.
return omap_32k_ticks_to_nsecs(omap_32k_sync_timer_read());
}
-static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id)
+/*
+ * 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)
{
- struct clock_event_device *evt = &clockevent_32k_timer;
+ 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;
- evt->event_handler(evt);
+ write_seqlock_irqsave(&xtime_lock, flags);
+ _omap_32k_timer_interrupt(irq, dev_id);
+ write_sequnlock_irqrestore(&xtime_lock, flags);
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,
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
}
#endif
- 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);
+ omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
}
/*
struct sys_timer omap_timer = {
.init = omap_timer_init,
+ .offset = NULL, /* Initialized later */
};
projects / linux-2.6-omap-h63xx.git / blobdiff