From af9dafb1dcf320a46783e09764c758bc4e32ed94 Mon Sep 17 00:00:00 2001 From: Lennert Buytenhek Date: Wed, 10 Aug 2011 02:37:55 +0800 Subject: [PATCH] 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 Acked-by: Haojian Zhuang Signed-off-by: Eric Miao --- arch/arm/mach-mmp/time.c | 47 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 35 insertions(+), 12 deletions(-) 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 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id) { 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 @@ static void __init timer_config(void) (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 @@ static void __init timer_config(void) __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 = { -- 2.7.4