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Message-ID: <a60d5949-a980-306a-e65a-6017b40a7321@gmail.com>
Date: Fri, 1 Nov 2019 16:55:12 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Chanwoo Choi <cw00.choi@...sung.com>
Cc: Thierry Reding <thierry.reding@...il.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Jonathan Hunter <jonathanh@...dia.com>,
Tomeu Vizoso <tomeu.vizoso@...labora.com>,
Peter Geis <pgwipeout@...il.com>, linux-pm@...r.kernel.org,
linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 17/19] PM / devfreq: tegra30: Support variable polling
interval
01.11.2019 10:41, Chanwoo Choi пишет:
> On 19. 10. 30. 오전 7:00, Dmitry Osipenko wrote:
>> 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@...il.com>
>> ---
>> drivers/devfreq/tegra30-devfreq.c | 35 ++++++++++++++++++++++++-------
>> 1 file changed, 28 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
>> index b745a973c35a..d0dd42856e5b 100644
>> --- a/drivers/devfreq/tegra30-devfreq.c
>> +++ b/drivers/devfreq/tegra30-devfreq.c
>> @@ -218,7 +218,7 @@ static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
>> {
>> 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;
>>
>> device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
>>
>> @@ -229,7 +229,7 @@ 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);
>> @@ -308,7 +308,7 @@ 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);
>> target_freq += dev->boost_freq;
>> @@ -465,7 +465,7 @@ 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);
>> @@ -506,7 +506,11 @@ static int tegra_actmon_start(struct tegra_devfreq *tegra)
>> unsigned int i;
>> int err;
>>
>> - actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
>> + if (!tegra->devfreq->profile->polling_ms ||
>> + tegra->devfreq->stop_polling)
>
> I think that the access of 'devfreq->stop_polling' is not good
> on governor. It is possible to alter with DEVFREQ_GOV_START/STOP/SUSPEND/RESUME
> notification.
Could you please clarify what you're meaning by "alter with notification"?
Do you mean to have the start/stop state tracking done by the
tegra30-devfreq driver itself?
>> + return 0;> +
>> + actmon_writel(tegra, tegra->devfreq->profile->polling_ms - 1,
>> ACTMON_GLB_PERIOD_CTRL);
>>
>> /*
>> @@ -554,6 +558,10 @@ static int tegra_actmon_start(struct tegra_devfreq *tegra)
>>
>> static void tegra_actmon_stop(struct tegra_devfreq *tegra)
>> {
>> + if (!tegra->devfreq->profile->polling_ms ||
>> + tegra->devfreq->stop_polling)
>
> ditto.
>
>> + return;
>> +
>> disable_irq(tegra->irq);
>>
>> cpufreq_unregister_notifier(&tegra->cpu_rate_change_nb,
>> @@ -623,7 +631,7 @@ 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);
>>
>> @@ -631,7 +639,7 @@ 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,
>> };
>> @@ -671,6 +679,7 @@ 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;
>>
>> /*
>> @@ -690,6 +699,17 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
>> devfreq_monitor_stop(devfreq);
>> break;
>>
>> + case DEVFREQ_GOV_INTERVAL:
>> + if (*new_delay > 256) {
>
> Need to add the comment why the maximum delay is under 256 ms.
Okay, will add comment in v8. The 256ms max is the hardware's capability.
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