From: Dmitry Osipenko Date: Mon, 4 Nov 2019 21:56:15 +0000 (+0300) Subject: PM / devfreq: tegra30: Support variable polling interval X-Git-Tag: v5.5-rc1~147^2~2^2^2~1 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f61ee201068ac844cc8ed7f9112e47f3452f8262;p=linux.git PM / devfreq: tegra30: Support variable polling interval 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 Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi --- 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)