[PATCH v9 17/19] PM / devfreq: tegra30: Support variable polling interval
From: Dmitry Osipenko
Date: Mon Nov 04 2019 - 17:02:07 EST
The ACTMON governor is interrupt-driven and currently hardware's polling
interval is fixed to 16ms in the driver. Devfreq supports variable polling
interval by the generic governors, let's re-use the generic interface for
changing of the polling interval. Now the polling interval can be changed
dynamically via /sys/class/devfreq/devfreq0/polling_interval.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/devfreq/tegra30-devfreq.c | 78 ++++++++++++++++++++++++++-----
1 file changed, 66 insertions(+), 12 deletions(-)
diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index 3bd920829bfd..e44f1a48f838 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -171,6 +171,8 @@ struct tegra_devfreq {
struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
unsigned int irq;
+
+ bool started;
};
struct tegra_actmon_emc_ratio {
@@ -209,18 +211,26 @@ static void device_writel(struct tegra_devfreq_device *dev, u32 val,
writel_relaxed(val, dev->regs + offset);
}
-static unsigned long do_percent(unsigned long val, unsigned int pct)
+static unsigned long do_percent(unsigned long long val, unsigned int pct)
{
- return val * pct / 100;
+ val = val * pct;
+ do_div(val, 100);
+
+ /*
+ * High freq + high boosting percent + large polling interval are
+ * resulting in integer overflow when watermarks are calculated.
+ */
+ return min_t(u64, val, U32_MAX);
}
static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
- u32 avg = dev->avg_count;
u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
- u32 band = avg_band_freq * ACTMON_SAMPLING_PERIOD;
+ u32 band = avg_band_freq * tegra->devfreq->profile->polling_ms;
+ u32 avg;
+ avg = min(dev->avg_count, U32_MAX - band);
device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
avg = max(dev->avg_count, band);
@@ -230,7 +240,7 @@ static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
- u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
+ u32 val = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
device_writel(dev, do_percent(val, dev->config->boost_up_threshold),
ACTMON_DEV_UPPER_WMARK);
@@ -309,7 +319,7 @@ static unsigned long actmon_device_target_freq(struct tegra_devfreq *tegra,
unsigned int avg_sustain_coef;
unsigned long target_freq;
- target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD;
+ target_freq = dev->avg_count / tegra->devfreq->profile->polling_ms;
avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
target_freq = do_percent(target_freq, avg_sustain_coef);
@@ -469,7 +479,7 @@ static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
dev->target_freq = tegra->cur_freq;
- dev->avg_count = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
+ dev->avg_count = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
device_writel(dev, dev->avg_count, ACTMON_DEV_INIT_AVG);
tegra_devfreq_update_avg_wmark(tegra, dev);
@@ -505,12 +515,15 @@ static void tegra_actmon_stop_devices(struct tegra_devfreq *tegra)
}
}
-static int tegra_actmon_start(struct tegra_devfreq *tegra)
+static int tegra_actmon_resume(struct tegra_devfreq *tegra)
{
unsigned int i;
int err;
- actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
+ if (!tegra->devfreq->profile->polling_ms || !tegra->started)
+ return 0;
+
+ actmon_writel(tegra, tegra->devfreq->profile->polling_ms - 1,
ACTMON_GLB_PERIOD_CTRL);
/*
@@ -558,8 +571,26 @@ static int tegra_actmon_start(struct tegra_devfreq *tegra)
return err;
}
-static void tegra_actmon_stop(struct tegra_devfreq *tegra)
+static int tegra_actmon_start(struct tegra_devfreq *tegra)
{
+ int ret = 0;
+
+ if (!tegra->started) {
+ tegra->started = true;
+
+ ret = tegra_actmon_resume(tegra);
+ if (ret)
+ tegra->started = false;
+ }
+
+ return ret;
+}
+
+static void tegra_actmon_pause(struct tegra_devfreq *tegra)
+{
+ if (!tegra->devfreq->profile->polling_ms || !tegra->started)
+ return;
+
disable_irq(tegra->irq);
cpufreq_unregister_notifier(&tegra->cpu_rate_change_nb,
@@ -572,6 +603,12 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
}
+static void tegra_actmon_stop(struct tegra_devfreq *tegra)
+{
+ tegra_actmon_pause(tegra);
+ tegra->started = false;
+}
+
static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
u32 flags)
{
@@ -629,7 +666,7 @@ 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 * cur_freq;
+ stat->total_time = tegra->devfreq->profile->polling_ms * cur_freq;
stat->busy_time = min(stat->busy_time, stat->total_time);
@@ -637,7 +674,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
}
static struct devfreq_dev_profile tegra_devfreq_profile = {
- .polling_ms = 0,
+ .polling_ms = ACTMON_SAMPLING_PERIOD,
.target = tegra_devfreq_target,
.get_dev_status = tegra_devfreq_get_dev_status,
};
@@ -677,6 +714,7 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
+ unsigned int *new_delay = data;
int ret = 0;
/*
@@ -696,6 +734,21 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
devfreq_monitor_stop(devfreq);
break;
+ case DEVFREQ_GOV_INTERVAL:
+ /*
+ * ACTMON hardware supports up to 256 milliseconds for the
+ * sampling period.
+ */
+ if (*new_delay > 256) {
+ ret = -EINVAL;
+ break;
+ }
+
+ tegra_actmon_pause(tegra);
+ devfreq_interval_update(devfreq, new_delay);
+ ret = tegra_actmon_resume(tegra);
+ break;
+
case DEVFREQ_GOV_SUSPEND:
tegra_actmon_stop(tegra);
devfreq_monitor_suspend(devfreq);
@@ -715,6 +768,7 @@ static struct devfreq_governor tegra_devfreq_governor = {
.get_target_freq = tegra_governor_get_target,
.event_handler = tegra_governor_event_handler,
.immutable = true,
+ .interrupt_driven = true,
};
static int tegra_devfreq_probe(struct platform_device *pdev)
--
2.23.0