PM / devfreq: tegra: Avoid inconsistency of current frequency value

The frequency value potentially could change in-between. It doesn't
cause any real problem at all right now, but that could change in the
future. Hence let's avoid the inconsistency.
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/tegra-devfreq.c

@@ -497,13 +497,15 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
 {
 	struct tegra_devfreq *tegra = dev_get_drvdata(dev);
 	struct tegra_devfreq_device *actmon_dev;
+	unsigned long cur_freq;
 
-	stat->current_frequency = tegra->cur_freq * KHZ;
+	cur_freq = READ_ONCE(tegra->cur_freq);
 
 	/* To be used by the tegra governor */
 	stat->private_data = tegra;
 
 	/* The below are to be used by the other governors */
+	stat->current_frequency = cur_freq * KHZ;
 
 	actmon_dev = &tegra->devices[MCALL];
 
@@ -514,7 +516,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
 	stat->busy_time *= 100 / BUS_SATURATION_RATIO;
 
 	/* Number of cycles in a sampling period */
-	stat->total_time = ACTMON_SAMPLING_PERIOD * tegra->cur_freq;
+	stat->total_time = ACTMON_SAMPLING_PERIOD * cur_freq;
 
 	stat->busy_time = min(stat->busy_time, stat->total_time);