ARM: 7085/2: mach-integrator: clockevent supports oneshot mode
authorLinus Walleij <linus.walleij@linaro.org>
Thu, 8 Sep 2011 20:21:42 +0000 (21:21 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Mon, 17 Oct 2011 08:12:43 +0000 (09:12 +0100)
The Integrator AP timer has no problem supporting oneshot
ticks with proper code, so let's do it so we can have
NOHZ configured in for this platform too.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/mach-integrator/integrator_ap.c

index aa30ab650183498ab78455cab1c0620d77cafe40..e66a8bce3999960ae41bd9ae2531175a07f481a2 100644 (file)
@@ -360,15 +360,29 @@ static void clkevt_set_mode(enum clock_event_mode mode, struct clock_event_devic
 {
        u32 ctrl = readl(clkevt_base + TIMER_CTRL) & ~TIMER_CTRL_ENABLE;
 
-       BUG_ON(mode == CLOCK_EVT_MODE_ONESHOT);
+       /* Disable timer */
+       writel(ctrl, clkevt_base + TIMER_CTRL);
 
-       if (mode == CLOCK_EVT_MODE_PERIODIC) {
-               writel(ctrl, clkevt_base + TIMER_CTRL);
+       switch (mode) {
+       case CLOCK_EVT_MODE_PERIODIC:
+               /* Enable the timer and start the periodic tick */
                writel(timer_reload, clkevt_base + TIMER_LOAD);
                ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
+               writel(ctrl, clkevt_base + TIMER_CTRL);
+               break;
+       case CLOCK_EVT_MODE_ONESHOT:
+               /* Leave the timer disabled, .set_next_event will enable it */
+               ctrl &= ~TIMER_CTRL_PERIODIC;
+               writel(ctrl, clkevt_base + TIMER_CTRL);
+               break;
+       case CLOCK_EVT_MODE_UNUSED:
+       case CLOCK_EVT_MODE_SHUTDOWN:
+       case CLOCK_EVT_MODE_RESUME:
+       default:
+               /* Just leave in disabled state */
+               break;
        }
 
-       writel(ctrl, clkevt_base + TIMER_CTRL);
 }
 
 static int clkevt_set_next_event(unsigned long next, struct clock_event_device *evt)
@@ -385,7 +399,7 @@ static int clkevt_set_next_event(unsigned long next, struct clock_event_device *
 static struct clock_event_device integrator_clockevent = {
        .name           = "timer1",
        .shift          = 34,
-       .features       = CLOCK_EVT_FEAT_PERIODIC,
+       .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
        .set_mode       = clkevt_set_mode,
        .set_next_event = clkevt_set_next_event,
        .rating         = 300,