Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / arch / arm / mach-pxa / time.c

diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
index 473fb61..b9b2057 100644 (file)
--- a/arch/arm/mach-pxa/time.c
+++ b/arch/arm/mach-pxa/time.c
@@ -70,6 +70,11 @@ static unsigned long pxa_gettimeoffset (void)
        return usec;
 }
 
+#ifdef CONFIG_NO_IDLE_HZ
+static unsigned long initial_match;
+static int match_posponed;
+#endif
+
 static irqreturn_t
 pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
@@ -77,11 +82,19 @@ pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 
        write_seqlock(&xtime_lock);
 
+#ifdef CONFIG_NO_IDLE_HZ
+       if (match_posponed) {
+               match_posponed = 0;
+               OSMR0 = initial_match;
+       }
+#endif
+
        /* Loop until we get ahead of the free running timer.
         * This ensures an exact clock tick count and time accuracy.
-        * IRQs are disabled inside the loop to ensure coherence between
-        * lost_ticks (updated in do_timer()) and the match reg value, so we
-        * can use do_gettimeofday() from interrupt handlers.
+        * 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.
         *
         * HACK ALERT: it seems that the PXA timer regs aren't updated right
         * away in all cases when a write occurs.  We therefore compare with
@@ -105,8 +118,8 @@ pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 
 static struct irqaction pxa_timer_irq = {
        .name           = "PXA Timer Tick",
-       .flags          = SA_INTERRUPT,
-       .handler        = pxa_timer_interrupt
+       .flags          = SA_INTERRUPT | SA_TIMER,
+       .handler        = pxa_timer_interrupt,
 };
 
 static void __init pxa_timer_init(void)
@@ -119,13 +132,51 @@ static void __init pxa_timer_init(void)
        tv.tv_sec = pxa_get_rtc_time();
        do_settimeofday(&tv);
 
-       OSMR0 = 0;              /* set initial match at 0 */
+       OIER = 0;               /* disable any timer interrupts */
+       OSCR = LATCH*2;         /* push OSCR out of the way */
+       OSMR0 = LATCH;          /* set initial match */
        OSSR = 0xf;             /* clear status on all timers */
        setup_irq(IRQ_OST0, &pxa_timer_irq);
-       OIER |= OIER_E0;        /* enable match on timer 0 to cause interrupts */
-       OSCR = 0;               /* initialize free-running timer, force first match */
+       OIER = OIER_E0;         /* enable match on timer 0 to cause interrupts */
+       OSCR = 0;               /* initialize free-running timer */
+}
+
+#ifdef CONFIG_NO_IDLE_HZ
+static int pxa_dyn_tick_enable_disable(void)
+{
+       /* nothing to do */
+       return 0;
+}
+
+static void pxa_dyn_tick_reprogram(unsigned long ticks)
+{
+       if (ticks > 1) {
+               initial_match = OSMR0;
+               OSMR0 = initial_match + ticks * LATCH;
+               match_posponed = 1;
+       }
 }
 
+static irqreturn_t
+pxa_dyn_tick_handler(int irq, void *dev_id, struct pt_regs *regs)
+{
+       if (match_posponed) {
+               match_posponed = 0;
+               OSMR0 = initial_match;
+               if ( (signed long)(initial_match - OSCR) <= 8 )
+                       return pxa_timer_interrupt(irq, dev_id, regs);
+       }
+       return IRQ_NONE;
+}
+
+static struct dyn_tick_timer pxa_dyn_tick = {
+       .enable         = pxa_dyn_tick_enable_disable,
+       .disable        = pxa_dyn_tick_enable_disable,
+       .reprogram      = pxa_dyn_tick_reprogram,
+       .handler        = pxa_dyn_tick_handler,
+};
+#endif
+
 #ifdef CONFIG_PM
 static unsigned long osmr[4], oier;
 
@@ -161,4 +212,7 @@ struct sys_timer pxa_timer = {
        .suspend        = pxa_timer_suspend,
        .resume         = pxa_timer_resume,
        .offset         = pxa_gettimeoffset,
+#ifdef CONFIG_NO_IDLE_HZ
+       .dyn_tick       = &pxa_dyn_tick,
+#endif
 };