[ARM] 2862/1: VST aka CONFIG_NO_IDLE_HZ support for PXA2xx
Patch from Nicolas Pitre
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
index 6e52021..72b15e9 100644
--- a/arch/arm/mach-pxa/time.c
+++ b/arch/arm/mach-pxa/time.c
@@ -70,6 +70,11 @@
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)
{
@@ -77,6 +82,13 @@
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
@@ -126,6 +138,42 @@
OSCR = 0; /* initialize free-running timer, force first match */
}
+#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 +209,7 @@
.suspend = pxa_timer_suspend,
.resume = pxa_timer_resume,
.offset = pxa_gettimeoffset,
+#ifdef CONFIG_NO_IDLE_HZ
+ .dyn_tick = &pxa_dyn_tick,
+#endif
};