diff options
Diffstat (limited to 'drivers/clocksource/arc_timer.c')
| -rw-r--r-- | drivers/clocksource/arc_timer.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/clocksource/arc_timer.c b/drivers/clocksource/arc_timer.c index 4927355f9cbe..471b428d8034 100644 --- a/drivers/clocksource/arc_timer.c +++ b/drivers/clocksource/arc_timer.c @@ -251,9 +251,14 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id) int irq_reenable = clockevent_state_periodic(evt); /* - * Any write to CTRL reg ACks the interrupt, we rewrite the - * Count when [N]ot [H]alted bit. - * And re-arm it if perioid by [I]nterrupt [E]nable bit + * 1. ACK the interrupt + * - For ARC700, any write to CTRL reg ACKs it, so just rewrite + * Count when [N]ot [H]alted bit. + * - For HS3x, it is a bit subtle. On taken count-down interrupt, + * IP bit [3] is set, which needs to be cleared for ACK'ing. + * The write below can only update the other two bits, hence + * explicitly clears IP bit + * 2. Re-arm interrupt if periodic by writing to IE bit [0] */ write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | TIMER_CTRL_NH); |