diff options
Diffstat (limited to 'drivers/clocksource/arm_arch_timer.c')
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 0445ad7e559e..8642504b7e51 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -334,7 +334,7 @@ static u64 notrace arm64_858921_read_cntvct_el0(void) do { \ _val = read_sysreg(reg); \ _retries--; \ - } while (((_val + 1) & GENMASK(9, 0)) <= 1 && _retries); \ + } while (((_val + 1) & GENMASK(8, 0)) <= 1 && _retries); \ \ WARN_ON_ONCE(!_retries); \ _val; \ @@ -827,15 +827,24 @@ static void arch_timer_evtstrm_enable(int divider) static void arch_timer_configure_evtstream(void) { - int evt_stream_div, pos; + int evt_stream_div, lsb; + + /* + * As the event stream can at most be generated at half the frequency + * of the counter, use half the frequency when computing the divider. + */ + evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ / 2; + + /* + * Find the closest power of two to the divisor. If the adjacent bit + * of lsb (last set bit, starts from 0) is set, then we use (lsb + 1). + */ + lsb = fls(evt_stream_div) - 1; + if (lsb > 0 && (evt_stream_div & BIT(lsb - 1))) + lsb++; - /* Find the closest power of two to the divisor */ - evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ; - pos = fls(evt_stream_div); - if (pos > 1 && !(evt_stream_div & (1 << (pos - 2)))) - pos--; /* enable event stream */ - arch_timer_evtstrm_enable(min(pos, 15)); + arch_timer_evtstrm_enable(max(0, min(lsb, 15))); } static void arch_counter_set_user_access(void) |