The average count may get out of sync if interrupt was disabled / avoided
for a long time due to upper watermark optimization, hence it should be
re-synced on each target's update to ensure that watermarks are set up
correctly on EMC rate-change notification and that a correct frequency
is selected for device.

Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
 drivers/devfreq/tegra30-devfreq.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/devfreq/tegra30-devfreq.c 
b/drivers/devfreq/tegra30-devfreq.c
index 4d582809acb6..8a674fad26be 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -466,11 +466,41 @@ static void actmon_isr_device(struct tegra_devfreq *tegra,
                              dev->boost_freq, cpufreq_get(0));
 }
 
+static void tegra_devfreq_sync_avg_count(struct tegra_devfreq *tegra,
+                                        struct tegra_devfreq_device *dev)
+{
+       u32 avg_count, avg_freq, old_upper, new_upper;
+
+       avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
+       avg_freq = avg_count / ACTMON_SAMPLING_PERIOD;
+
+       old_upper = tegra_actmon_upper_freq(tegra, dev->avg_freq);
+       new_upper = tegra_actmon_upper_freq(tegra, avg_freq);
+
+       /* similar to ISR, see comments in actmon_isr_device() */
+       if (old_upper != new_upper) {
+               dev->avg_freq = avg_freq;
+               dev->boost_freq = 0;
+       }
+}
+
 static unsigned long actmon_update_target(struct tegra_devfreq *tegra,
                                          struct tegra_devfreq_device *dev)
 {
        unsigned long target_freq;
 
+       /*
+        * The avg_count / avg_freq is getting snapshoted on device's
+        * interrupt, but there are cases where actual value need to
+        * be utilized on target's update, like CPUFreq boosting and
+        * overriding the min freq via /sys/class/devfreq/devfreq0/min_freq
+        * because we're optimizing the upper watermark based on the
+        * actual EMC frequency. This means that interrupt may be
+        * inactive for a long time and thus making snapshoted value
+        * outdated.
+        */
+       tegra_devfreq_sync_avg_count(tegra, dev);
+
        target_freq = min(dev->avg_freq + dev->boost_freq, KHZ_MAX);
        target_freq = tegra_actmon_account_cpu_freq(tegra, dev, target_freq);
 
-- 
2.22.0

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