ARM: mmp: Change the way we use timer 0 as clockevent timer.
Instead of setting up a match interrupt for 'current_time + delta'
on ->set_next_event(), program timer 0 to count down from 'delta - 1'
and trigger an interrupt when it reaches zero.
Signed-off-by: Lennert Buytenhek <buytenh@laptop.org>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-mmp/time.c b/arch/arm/mach-mmp/time.c
index c53715e..4e91ee6 100644
--- a/arch/arm/mach-mmp/time.c
+++ b/arch/arm/mach-mmp/time.c
@@ -75,28 +75,51 @@
{
struct clock_event_device *c = dev_id;
- /* disable and clear pending interrupt status */
- __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0));
- __raw_writel(0x1, TIMERS_VIRT_BASE + TMR_ICR(0));
+ /*
+ * Clear pending interrupt status.
+ */
+ __raw_writel(0x01, TIMERS_VIRT_BASE + TMR_ICR(0));
+
+ /*
+ * Disable timer 0.
+ */
+ __raw_writel(0x02, TIMERS_VIRT_BASE + TMR_CER);
+
c->event_handler(c);
+
return IRQ_HANDLED;
}
static int timer_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
- unsigned long flags, next;
+ unsigned long flags;
local_irq_save(flags);
- /* clear pending interrupt status and enable */
+ /*
+ * Disable timer 0.
+ */
+ __raw_writel(0x02, TIMERS_VIRT_BASE + TMR_CER);
+
+ /*
+ * Clear and enable timer match 0 interrupt.
+ */
__raw_writel(0x01, TIMERS_VIRT_BASE + TMR_ICR(0));
__raw_writel(0x01, TIMERS_VIRT_BASE + TMR_IER(0));
- next = timer_read() + delta;
- __raw_writel(next, TIMERS_VIRT_BASE + TMR_TN_MM(0, 0));
+ /*
+ * Setup new clockevent timer value.
+ */
+ __raw_writel(delta - 1, TIMERS_VIRT_BASE + TMR_TN_MM(0, 0));
+
+ /*
+ * Enable timer 0.
+ */
+ __raw_writel(0x03, TIMERS_VIRT_BASE + TMR_CER);
local_irq_restore(flags);
+
return 0;
}
@@ -152,10 +175,10 @@
(TMR_CCR_CS_0(3) | TMR_CCR_CS_1(3));
__raw_writel(ccr, TIMERS_VIRT_BASE + TMR_CCR);
- /* free-running mode */
- __raw_writel(0x3, TIMERS_VIRT_BASE + TMR_CMR);
+ /* set timer 0 to periodic mode, and timer 1 to free-running mode */
+ __raw_writel(0x2, TIMERS_VIRT_BASE + TMR_CMR);
- __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_PLCR(0)); /* free-running */
+ __raw_writel(0x1, TIMERS_VIRT_BASE + TMR_PLCR(0)); /* periodic */
__raw_writel(0x7, TIMERS_VIRT_BASE + TMR_ICR(0)); /* clear status */
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0));
@@ -163,8 +186,8 @@
__raw_writel(0x7, TIMERS_VIRT_BASE + TMR_ICR(1)); /* clear status */
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(1));
- /* enable timer counter */
- __raw_writel(0x3, TIMERS_VIRT_BASE + TMR_CER);
+ /* enable timer 1 counter */
+ __raw_writel(0x2, TIMERS_VIRT_BASE + TMR_CER);
}
static struct irqaction timer_irq = {