cpufreq: interactive governor drops bits in time calculation

Keep time calculation in 64-bit throughout. If we have long times
between idle calculations this can result in deltas > 32 bits
which causes incorrect load percentage calculations and selecting
the wrong frequencies if we truncate here.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 7f1782ade53c41fce27d5b233a9d79a7f0884058..a494fbd7dbe818e3add477e03c19ad59e52641bb 100644 (file)
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -316,13 +316,13 @@ static u64 update_load(int cpu)
                pcpu->policy->governor_data;
        u64 now;
        u64 now_idle;
-       unsigned int delta_idle;
-       unsigned int delta_time;
+       u64 delta_idle;
+       u64 delta_time;
        u64 active_time;
 
        now_idle = get_cpu_idle_time(cpu, &now, tunables->io_is_busy);
-       delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
-       delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
+       delta_idle = (now_idle - pcpu->time_in_idle);
+       delta_time = (now - pcpu->time_in_idle_timestamp);
 
        if (delta_time <= delta_idle)
                active_time = 0;