clocksource: sh_cmt: One-off clockevent fix V2
Magnus Damm [Wed, 4 Aug 2010 04:31:38 +0000 (04:31 +0000)]
Fix a one-off error in the CMT driver V2. The match register
should be programmed with the period minus one.

Many thanks to Eiraku-san for tracking down this issue.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/clocksource/sh_cmt.c

index 717305d..ed8e07b 100644 (file)
@@ -308,7 +308,7 @@ static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
         * isr before we end up here.
         */
        if (p->flags & FLAG_CLOCKSOURCE)
-               p->total_cycles += p->match_value;
+               p->total_cycles += p->match_value + 1;
 
        if (!(p->flags & FLAG_REPROGRAM))
                p->next_match_value = p->max_match_value;
@@ -403,7 +403,7 @@ static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
        raw = sh_cmt_get_counter(p, &has_wrapped);
 
        if (unlikely(has_wrapped))
-               raw += p->match_value;
+               raw += p->match_value + 1;
        spin_unlock_irqrestore(&p->lock, flags);
 
        return value + raw;
@@ -478,7 +478,7 @@ static void sh_cmt_clock_event_start(struct sh_cmt_priv *p, int periodic)
        ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
 
        if (periodic)
-               sh_cmt_set_next(p, (p->rate + HZ/2) / HZ);
+               sh_cmt_set_next(p, ((p->rate + HZ/2) / HZ) - 1);
        else
                sh_cmt_set_next(p, p->max_match_value);
 }
@@ -523,9 +523,9 @@ static int sh_cmt_clock_event_next(unsigned long delta,
 
        BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
        if (likely(p->flags & FLAG_IRQCONTEXT))
-               p->next_match_value = delta;
+               p->next_match_value = delta - 1;
        else
-               sh_cmt_set_next(p, delta);
+               sh_cmt_set_next(p, delta - 1);
 
        return 0;
 }