[ARM] sa1100: add clock event support

d142b6e77d394a4fcc0a42381b03852bd9c4e263 added clock source support,
now it's time for the clock event support.

Tested-by: Thomas Kunze <thommycheck@gmx.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1f7c728f5ce50638f08bf542f34bba604412bfd3..63cc733fdb3218af059954a05e781aaa0e70128b 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -425,6 +425,8 @@ config ARCH_SA1100
        select ARCH_MTD_XIP
        select GENERIC_GPIO
        select GENERIC_TIME
+       select GENERIC_CLOCKEVENTS
+       select TICK_ONESHOT
        select HAVE_IDE
        select HAVE_GPIO_LIB
        help

diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c
index c2677368d6af9568d97616b6d0d6becb1a3a5385..a9799cb35b74aebe0d005adb6c547b83e92e5b21 100644 (file)
--- a/arch/arm/mach-sa1100/time.c
+++ b/arch/arm/mach-sa1100/time.c
@@ -13,67 +13,69 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/timex.h>
-#include <linux/signal.h>
-#include <linux/clocksource.h>
+#include <linux/clockchips.h>
 
 #include <asm/mach/time.h>
 #include <asm/hardware.h>
 
-#define RTC_DEF_DIVIDER                (32768 - 1)
-#define RTC_DEF_TRIM            0
+#define MIN_OSCR_DELTA 2
 
-static int sa1100_set_rtc(void)
+static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id)
 {
-       unsigned long current_time = xtime.tv_sec;
+       struct clock_event_device *c = dev_id;
 
-       if (RTSR & RTSR_ALE) {
-               /* make sure not to forward the clock over an alarm */
-               unsigned long alarm = RTAR;
-               if (current_time >= alarm && alarm >= RCNR)
-                       return -ERESTARTSYS;
-       }
-       RCNR = current_time;
-       return 0;
-}
+       /* Disarm the compare/match, signal the event. */
+       OIER &= ~OIER_E0;
+       OSSR = OSSR_M0;
+       c->event_handler(c);
 
-#ifdef CONFIG_NO_IDLE_HZ
-static unsigned long initial_match;
-static int match_posponed;
-#endif
+       return IRQ_HANDLED;
+}
 
-static irqreturn_t
-sa1100_timer_interrupt(int irq, void *dev_id)
+static int
+sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
 {
-       unsigned int next_match;
+       unsigned long flags, next, oscr;
 
-#ifdef CONFIG_NO_IDLE_HZ
-       if (match_posponed) {
-               match_posponed = 0;
-               OSMR0 = initial_match;
-       }
-#endif
+       raw_local_irq_save(flags);
+       OIER |= OIER_E0;
+       next = OSCR + delta;
+       OSMR0 = next;
+       oscr = OSCR;
+       raw_local_irq_restore(flags);
 
-       /*
-        * Loop until we get ahead of the free running timer.
-        * This ensures an exact clock tick count and time accuracy.
-        * 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.
-        */
-       do {
-               timer_tick();
-               OSSR = OSSR_M0;  /* Clear match on timer 0 */
-               next_match = (OSMR0 += LATCH);
-       } while ((signed long)(next_match - OSCR) <= 0);
+       return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
+}
 
-       return IRQ_HANDLED;
+static void
+sa1100_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c)
+{
+       unsigned long flags;
+
+       switch (mode) {
+       case CLOCK_EVT_MODE_ONESHOT:
+       case CLOCK_EVT_MODE_UNUSED:
+       case CLOCK_EVT_MODE_SHUTDOWN:
+               raw_local_irq_save(flags);
+               OIER &= ~OIER_E0;
+               OSSR = OSSR_M0;
+               raw_local_irq_restore(flags);
+               break;
+
+       case CLOCK_EVT_MODE_RESUME:
+       case CLOCK_EVT_MODE_PERIODIC:
+               break;
+       }
 }
 
-static struct irqaction sa1100_timer_irq = {
-       .name           = "SA11xx Timer Tick",
-       .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
-       .handler        = sa1100_timer_interrupt,
+static struct clock_event_device ckevt_sa1100_osmr0 = {
+       .name           = "osmr0",
+       .features       = CLOCK_EVT_FEAT_ONESHOT,
+       .shift          = 32,
+       .rating         = 200,
+       .cpumask        = CPU_MASK_CPU0,
+       .set_next_event = sa1100_osmr0_set_next_event,
+       .set_mode       = sa1100_osmr0_set_mode,
 };
 
 static cycle_t sa1100_read_oscr(void)
@@ -90,62 +92,34 @@ static struct clocksource cksrc_sa1100_oscr = {
        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
+static struct irqaction sa1100_timer_irq = {
+       .name           = "ost0",
+       .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+       .handler        = sa1100_ost0_interrupt,
+       .dev_id         = &ckevt_sa1100_osmr0,
+};
+
 static void __init sa1100_timer_init(void)
 {
-       unsigned long flags;
-
-       set_rtc = sa1100_set_rtc;
-
        OIER = 0;               /* disable any timer interrupts */
        OSSR = 0xf;             /* clear status on all timers */
-       setup_irq(IRQ_OST0, &sa1100_timer_irq);
-       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);
+
+       ckevt_sa1100_osmr0.mult =
+               div_sc(3686400, NSEC_PER_SEC, ckevt_sa1100_osmr0.shift);
+       ckevt_sa1100_osmr0.max_delta_ns =
+               clockevent_delta2ns(0x7fffffff, &ckevt_sa1100_osmr0);
+       ckevt_sa1100_osmr0.min_delta_ns =
+               clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_sa1100_osmr0) + 1;
 
        cksrc_sa1100_oscr.mult =
                clocksource_hz2mult(CLOCK_TICK_RATE, cksrc_sa1100_oscr.shift);
 
-       clocksource_register(&cksrc_sa1100_oscr);
-}
-
-#ifdef CONFIG_NO_IDLE_HZ
-static int sa1100_dyn_tick_enable_disable(void)
-{
-       /* nothing to do */
-       return 0;
-}
-
-static void sa1100_dyn_tick_reprogram(unsigned long ticks)
-{
-       if (ticks > 1) {
-               initial_match = OSMR0;
-               OSMR0 = initial_match + ticks * LATCH;
-               match_posponed = 1;
-       }
-}
+       setup_irq(IRQ_OST0, &sa1100_timer_irq);
 
-static irqreturn_t
-sa1100_dyn_tick_handler(int irq, void *dev_id)
-{
-       if (match_posponed) {
-               match_posponed = 0;
-               OSMR0 = initial_match;
-               if ((signed long)(initial_match - OSCR) <= 0)
-                       return sa1100_timer_interrupt(irq, dev_id);
-       }
-       return IRQ_NONE;
+       clocksource_register(&cksrc_sa1100_oscr);
+       clockevents_register_device(&ckevt_sa1100_osmr0);
 }
 
-static struct dyn_tick_timer sa1100_dyn_tick = {
-       .enable         = sa1100_dyn_tick_enable_disable,
-       .disable        = sa1100_dyn_tick_enable_disable,
-       .reprogram      = sa1100_dyn_tick_reprogram,
-       .handler        = sa1100_dyn_tick_handler,
-};
-#endif
-
 #ifdef CONFIG_PM
 unsigned long osmr[4], oier;
 
@@ -181,7 +155,4 @@ struct sys_timer sa1100_timer = {
        .init           = sa1100_timer_init,
        .suspend        = sa1100_timer_suspend,
        .resume         = sa1100_timer_resume,
-#ifdef CONFIG_NO_IDLE_HZ
-       .dyn_tick       = &sa1100_dyn_tick,
-#endif
 };