[PATCH v4 19/24] PM / devfreq: tegra30: Optimize upper consecutive watermark selection

Dmitry Osipenko
2019-07-07T22:32:58Z

The memory activity counter may get a bit higher than a watermark which
is selected based on OPP that corresponds to a highest EMC rate, in this
case watermark is lower than the actual memory activity is and thus
results in unwanted "upper" interrupts.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/devfreq/tegra30-devfreq.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index 8d6bf6e9f1ae..c3cf87231d25 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -363,7 +363,18 @@ static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, &upper);

delta = do_percent(upper - lower, dev->config->boost_up_threshold);
- device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK);
+
+ /*
+ * The memory events count could go a bit higher than the maximum
+ * defined by the OPPs, hence make the upper watermark infinitely
+ * high to avoid unnecessary upper interrupts in that case.
+ */
+ if (freq == tegra->max_freq)
+ upper = ULONG_MAX;
+ else
+ upper = lower + delta;
+
+ device_writel(dev, upper, ACTMON_DEV_UPPER_WMARK);

/*
* Meanwhile the lower mark is based on the average value
--
2.22.0