ARM: OMAP: Add clockevent driver for OMAP.
This is an update of the initial patch from Daniel Walker
and Kevin Hilman. Update to apply cleanly to 2.6.20-rc1 by
Dirk Behme.
Signed-off-by: Dirk Behme <dirk.behme_at_gmail.com>
Index: linux-2.6.20-rc1/arch/arm/mach-omap1/time.c
===================================================================
--- linux-2.6.20-rc1.orig/arch/arm/mach-omap1/time.c
+++ linux-2.6.20-rc1/arch/arm/mach-omap1/time.c
@@ -42,6 +42,7 @@
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <asm/system.h>
#include <asm/hardware.h>
@@ -102,15 +103,33 @@ static inline unsigned long omap_mpu_tim
return timer->read_tim;
}
-static inline void omap_mpu_timer_start(int nr, unsigned long load_val)
+static inline void omap_mpu_set_autoreset(int nr)
+{
+ volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
+
+ timer->cntl = timer->cntl | MPU_TIMER_AR;
+}
+
+static inline void omap_mpu_remove_autoreset(int nr)
{
volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
+ timer->cntl = timer->cntl & ~MPU_TIMER_AR;
+}
+
+static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
+ int autoreset)
+{
+ volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
+ unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST);
+
+ if (autoreset) timerflags |= MPU_TIMER_AR;
+
timer->cntl = MPU_TIMER_CLOCK_ENABLE;
udelay(1);
timer->load_tim = load_val;
udelay(1);
- timer->cntl = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_AR | MPU_TIMER_ST);
+ timer->cntl = timerflags;
}
/*
@@ -118,12 +137,39 @@ static inline void omap_mpu_timer_start(
* MPU timer 1 ... count down to zero, interrupt, reload
* ---------------------------------------------------------------------------
*/
+static void omap_mpu_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ omap_mpu_timer_start(0, cycles, 0);
+}
+
+static void omap_mpu_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_PERIODIC:
+ omap_mpu_set_autoreset(0);
+ break;
+ case CLOCK_EVT_ONESHOT:
+ omap_mpu_remove_autoreset(0);
+ break;
+ case CLOCK_EVT_SHUTDOWN:
+ break;
+ }
+}
+
+static struct clock_event_device clockevent_mpu_timer1 = {
+ .name = "mpu_timer1",
+ .capabilities = CLOCK_CAP_NEXTEVT | CLOCK_CAP_TICK |
+ CLOCK_CAP_UPDATE,
+ .shift = 32,
+ .set_next_event = omap_mpu_set_next_event,
+ .set_mode = omap_mpu_set_mode,
+};
+
static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
{
- write_seqlock(&xtime_lock);
- /* NOTE: no lost-tick detection/handling! */
- timer_tick();
- write_sequnlock(&xtime_lock);
+ clockevent_mpu_timer1.event_handler();
return IRQ_HANDLED;
}
@@ -139,9 +185,19 @@ static __init void omap_init_mpu_timer(u
set_cyc2ns_scale(rate / 1000);
setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
- omap_mpu_timer_start(0, (rate / HZ) - 1);
+ omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
+
+ clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC,
+ clockevent_mpu_timer1.shift);
+ clockevent_mpu_timer1.max_delta_ns =
+ clockevent_delta2ns(-1, &clockevent_mpu_timer1);
+ clockevent_mpu_timer1.min_delta_ns =
+ clockevent_delta2ns(1, &clockevent_mpu_timer1);
+
+ register_global_clockevent(&clockevent_mpu_timer1);
}
+
/*
* ---------------------------------------------------------------------------
* MPU timer 2 ... free running 32-bit clock source and scheduler clock
@@ -185,7 +241,7 @@ static void __init omap_init_clocksource
= clocksource_khz2mult(rate/1000, clocksource_mpu.shift);
setup_irq(INT_TIMER2, &omap_mpu_timer2_irq);
- omap_mpu_timer_start(1, ~0);
+ omap_mpu_timer_start(1, ~0, 1);
if (clocksource_register(&clocksource_mpu))
printk(err, clocksource_mpu.name);
Index: linux-2.6.20-rc1/arch/arm/plat-omap/Kconfig
===================================================================
--- linux-2.6.20-rc1.orig/arch/arm/plat-omap/Kconfig
+++ linux-2.6.20-rc1/arch/arm/plat-omap/Kconfig
@@ -11,6 +11,7 @@ choice
config ARCH_OMAP1
bool "TI OMAP1"
+ select GENERIC_CLOCKEVENTS
config ARCH_OMAP2
bool "TI OMAP2"
Index: linux-2.6.20-rc1/arch/arm/plat-omap/timer32k.c
===================================================================
--- linux-2.6.20-rc1.orig/arch/arm/plat-omap/timer32k.c
+++ linux-2.6.20-rc1/arch/arm/plat-omap/timer32k.c
@@ -43,6 +43,7 @@
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <asm/system.h>
#include <asm/hardware.h>
@@ -81,13 +82,13 @@ struct sys_timer omap_timer;
#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)
@@ -143,6 +144,49 @@ static inline void omap_32k_timer_ack_ir
#endif
+static void omap_32k_timer_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ omap_32k_timer_stop();
+ omap_32k_timer_start(cycles);
+ local_irq_restore(flags);
+}
+
+static void omap_32k_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ static int periodic_requests = 0;
+
+ switch (mode) {
+ case CLOCK_EVT_ONESHOT:
+ /* 32k timer does not have one-shot support in hardware.
+ * instead, wet just to a stop in the next_event hook,
+ * and dont support PERIODIC */
+ break;
+ case CLOCK_EVT_PERIODIC:
+ if (periodic_requests)
+ printk(KERN_ERR "32k-timer: CLOCK_EVT_PERIODIC "
+ "is not supported.\n");
+ periodic_requests++;
+ break;
+ case CLOCK_EVT_SHUTDOWN:
+ omap_32k_timer_stop();
+ break;
+ }
+}
+
+static struct clock_event_device clockevent_32k_timer = {
+ .name = "32k-timer",
+ .capabilities = CLOCK_CAP_NEXTEVT | CLOCK_CAP_TICK |
+ CLOCK_CAP_UPDATE,
+ .shift = 32,
+ .set_next_event = omap_32k_timer_set_next_event,
+ .set_mode = omap_32k_timer_set_mode,
+};
+
/*
* The 32KHz synchronized timer is an additional timer on 16xx.
* It is always running.
@@ -180,107 +224,15 @@ unsigned long long sched_clock(void)
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_interrupt(int irq, void *dev_id)
{
- unsigned long flags;
+ omap_32k_timer_ack_irq();
- write_seqlock_irqsave(&xtime_lock, flags);
- _omap_32k_timer_interrupt(irq, dev_id);
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ clockevent_32k_timer.event_handler();
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 irqreturn_t omap_32k_timer_handler(int irq, void *dev_id)
-{
- unsigned long now;
-
- now = omap_32k_sync_timer_read();
-
- /* Don't bother reprogramming timer if last tick was before next
- * jiffie. We will get another interrupt when previously programmed
- * timer expires. This cuts down interrupt load quite a bit.
- */
- if (now - omap_32k_last_tick < OMAP_32K_TICKS_PER_HZ)
- return IRQ_HANDLED;
-
- return _omap_32k_timer_interrupt(irq, dev_id);
-}
-
-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,
@@ -289,10 +241,6 @@ static struct irqaction omap_32k_timer_i
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_32k_last_tick = omap_32k_sync_timer_read();
@@ -312,6 +260,16 @@ static __init void omap_init_32k_timer(v
#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);
+
+ register_global_clockevent(&clockevent_32k_timer);
}
/*
