static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
int absolute)
{
unsigned long new_match;
unsigned long value = p->next_match_value;
unsigned long delay = 0;
unsigned long now = 0;
int has_wrapped;
now = sh_cmt_get_counter(p, &has_wrapped);
p->flags |= FLAG_REPROGRAM;
if (has_wrapped) {
p->flags |= FLAG_SKIPEVENT;
return;
}
if (absolute)
now = 0;
do {
new_match = now + value + delay;
if (new_match > p->max_match_value)
new_match = p->max_match_value;
sh_cmt_write(p, CMCOR, new_match);
now = sh_cmt_get_counter(p, &has_wrapped);
if (has_wrapped && (new_match > p->match_value)) {
p->flags |= FLAG_SKIPEVENT;
break;
}
if (has_wrapped) {
p->match_value = new_match;
break;
}
if (now < new_match) {
p->match_value = new_match;
break;
}
if (delay)
delay <<= 1;
else
delay = 1;
if (!delay)
pr_warning("sh_cmt: too long delay\n");
} while (delay);
}
static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
{
struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
unsigned long flags, raw;
unsigned long value;
int has_wrapped;
spin_lock_irqsave(&p->lock, flags);
value = p->total_cycles;
raw = sh_cmt_get_counter(p, &has_wrapped);
if (unlikely(has_wrapped))
raw += p->match_value;
spin_unlock_irqrestore(&p->lock, flags);
return value + raw;
}
static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
int absolute)
{
unsigned long new_match;
unsigned long value = p->next_match_value;
unsigned long delay = 0;
unsigned long now = 0;
int has_wrapped;
now = sh_cmt_get_counter(p, &has_wrapped);
p->flags |= FLAG_REPROGRAM; /* force reprogram */
if (has_wrapped) {
/* we're competing with the interrupt handler.
* -> let the interrupt handler reprogram the timer.
* -> interrupt number two handles the event.
*/
p->flags |= FLAG_SKIPEVENT;
return;
}
if (absolute)
now = 0;
do {
/* reprogram the timer hardware,
* but don't save the new match value yet.
*/
new_match = now + value + delay;
if (new_match > p->max_match_value)
new_match = p->max_match_value;
sh_cmt_write(p, CMCOR, new_match);
now = sh_cmt_get_counter(p, &has_wrapped);
if (has_wrapped && (new_match > p->match_value)) {
/* we are changing to a greater match value,
* so this wrap must be caused by the counter
* matching the old value.
* -> first interrupt reprograms the timer.
* -> interrupt number two handles the event.
*/
p->flags |= FLAG_SKIPEVENT;
break;
}
if (has_wrapped) {
/* we are changing to a smaller match value,
* so the wrap must be caused by the counter
* matching the new value.
* -> save programmed match value.
* -> let isr handle the event.
*/
p->match_value = new_match;
break;
}
/* be safe: verify hardware settings */
if (now < new_match) {
/* timer value is below match value, all good.
* this makes sure we won't miss any match events.
* -> save programmed match value.
* -> let isr handle the event.
*/
p->match_value = new_match;
break;
}
/* the counter has reached a value greater
* than our new match value. and since the
* has_wrapped flag isn't set we must have
* programmed a too close event.
* -> increase delay and retry.
*/
if (delay)
delay <<= 1;
else
delay = 1;
if (!delay)
pr_warning("sh_cmt: too long delay\n");
} while (delay);
}
