ACPI: Minor cleanup eliminating redundant PMTIMER_TICKS to NS conversion

acpi_enter_[simple,bm] does
idle timing in ns, convert it to timeval, then to us, then to
pmtimer_ticks and then back to ns.

This patch changes things to
idle timing in ns, convert it to us, and then to pmtimer_ticks.

Just saves an imul along this path, but makes the code cleaner.

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 63a3d4b8c238..43fe52f9834b 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -859,6 +859,7 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
         struct acpi_processor *pr;
         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
         ktime_t  kt1, kt2;
+        s64 idle_time_ns;
         s64 idle_time;
         s64 sleep_ticks = 0;
 
@@ -900,12 +901,14 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
         sched_clock_idle_sleep_event();
         acpi_idle_do_entry(cx);
         kt2 = ktime_get_real();
-        idle_time =  ktime_to_us(ktime_sub(kt2, kt1));
+        idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));
+        idle_time = idle_time_ns;
+        do_div(idle_time, NSEC_PER_USEC);
 
         sleep_ticks = us_to_pm_timer_ticks(idle_time);
 
         /* Tell the scheduler how much we idled: */
-        sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+        sched_clock_idle_wakeup_event(idle_time_ns);
 
         local_irq_enable();
         current_thread_info()->status |= TS_POLLING;
@@ -933,6 +936,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
         struct acpi_processor *pr;
         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
         ktime_t  kt1, kt2;
+        s64 idle_time_ns;
         s64 idle_time;
         s64 sleep_ticks = 0;
 
@@ -1015,11 +1019,13 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
                 spin_unlock(&c3_lock);
         }
         kt2 = ktime_get_real();
-        idle_time =  ktime_to_us(ktime_sub(kt2, kt1));
+        idle_time_ns = ktime_to_us(ktime_sub(kt2, kt1));
+        idle_time = idle_time_ns;
+        do_div(idle_time, NSEC_PER_USEC);
 
         sleep_ticks = us_to_pm_timer_ticks(idle_time);
         /* Tell the scheduler how much we idled: */
-        sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+        sched_clock_idle_wakeup_event(idle_time_ns);
 
         local_irq_enable();
         current_thread_info()->status |= TS_POLLING;