Re: [PATCH v6 4/8] thermal:boost: Automatic enable/disable of BOOST feature

Lukasz Majewski
2013-08-12T09:18:02Z

Dear Zhang, Eduardo,

> This patch provides auto disable/enable operation for boost. When any
> defined trip point is passed, the boost is disabled.
> In that moment thermal monitor workqueue is woken up and it monitors
> if the device temperature drops below 75% of the smallest trip point.
> When device cools down, the boost is enabled again.
>
> Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
> Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
>
> ---
> Changes for v6:
> - Disable boost only when supported and enabled
> - Protect boost related thermal_zone_device struct fields with mutex
> - Evaluate temperature trend during boost enable decision
> - Create separate methods to handle boost enable/disable
> (thermal_boost_{enable|disable}) operations
> - Boost is disabled at any trip point passage (not only the non
> critical one)
> - Add stub definitions for cpufreq boost functions used when
> CONFIG_CPU_FREQ is NOT defined.
>
> Changes for v5:
> - Move boost disable code from cpu_cooling.c to thermal_core.c
> (to handle_non_critical_trips)
> - Extent struct thermal_zone_device by adding overheated bool flag
> - Implement auto enable of boost after device cools down
> - Introduce boost_polling flag, which indicates if thermal uses it's
> predefined pool delay or has woken up thermal workqueue only to wait
> until device cools down.
>
> Changes for v4:
> - New patch
>

ping...

> drivers/thermal/thermal_core.c | 55
> ++++++++++++++++++++++++++++++++++++++++
> include/linux/cpufreq.h | 15 +++++++++++
> include/linux/thermal.h | 2 ++ 3 files changed, 72
> insertions(+)
>
> diff --git a/drivers/thermal/thermal_core.c
> b/drivers/thermal/thermal_core.c index 1f02e8e..8f4be55 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -34,6 +34,7 @@
> #include <linux/thermal.h>
> #include <linux/reboot.h>
> #include <linux/string.h>
> +#include <linux/cpufreq.h>
> #include <net/netlink.h>
> #include <net/genetlink.h>
>
> @@ -354,9 +355,59 @@ static void handle_critical_trips(struct
> thermal_zone_device *tz, }
> }
>
> +static int thermal_boost_enable(struct thermal_zone_device *tz)
> +{
> + enum thermal_trend trend = get_tz_trend(tz, 0);
> + long trip_temp;
> +
> + if (!tz->ops->get_trip_temp || !tz->overheated)
> + return -EPERM;
> + if (trend == THERMAL_TREND_RAISING || trend ==
> THERMAL_TREND_RAISE_FULL)
> + return -EBUSY;
> +
> + tz->ops->get_trip_temp(tz, 0, &trip_temp);
> + /*
> + * Enable boost again only when current temperature is less
> + * than 75% of trip_temp[0]
> + */
> + if ((tz->temperature + (trip_temp >> 2)) < trip_temp) {
> + mutex_lock(&tz->lock);
> + tz->overheated = false;
> + if (tz->boost_polling) {
> + tz->boost_polling = false;
> + tz->polling_delay = 0;
> + }
> + mutex_unlock(&tz->lock);
> + cpufreq_boost_trigger_state(1);
> + return 0;
> + }
> + return -EBUSY;
> +}
> +
> +static void thermal_boost_disable(struct thermal_zone_device *tz)
> +{
> + cpufreq_boost_trigger_state(0);
> +
> + /*
> + * If no workqueue for monitoring is running - start one with
> + * 1000 ms monitoring period
> + * If workqueue already running - do not change its period
> and only
> + * test if target CPU has cooled down
> + */
> + mutex_lock(&tz->lock);
> + if (!tz->polling_delay) {
> + tz->boost_polling = true;
> + tz->polling_delay = 1000;
> + }
> + tz->overheated = true;
> + mutex_unlock(&tz->lock);
> +}
> +
> static void handle_thermal_trip(struct thermal_zone_device *tz, int
> trip) {
> enum thermal_trip_type type;
> + if (cpufreq_boost_supported() && cpufreq_boost_enabled())
> + thermal_boost_disable(tz);
>
> tz->ops->get_trip_type(tz, trip, &type);
>
> @@ -455,6 +506,10 @@ static void thermal_zone_device_check(struct
> work_struct *work) struct thermal_zone_device *tz =
> container_of(work, struct thermal_zone_device,
> poll_queue.work);
> + if (cpufreq_boost_supported())
> + if (!thermal_boost_enable(tz))
> + return;
> +
> thermal_zone_device_update(tz);
> }
>
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 49a73c9..3d9276d 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -435,9 +435,24 @@ int cpufreq_frequency_table_target(struct
> cpufreq_policy *policy, unsigned int relation,
> unsigned int *index);
>
> +#ifdef CONFIG_CPU_FREQ
> int cpufreq_boost_trigger_state(int state);
> int cpufreq_boost_supported(void);
> int cpufreq_boost_enabled(void);
> +#else
> +static inline int cpufreq_boost_trigger_state(int state)
> +{
> + return 0;
> +}
> +static inline int cpufreq_boost_supported(void)
> +{
> + return 0;
> +}
> +static inline int cpufreq_boost_enabled(void)
> +{
> + return 0;
> +}
> +#endif
> /* the following 3 funtions are for cpufreq core use only */
> struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned
> int cpu);
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index a386a1c..f1aa3c2 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -172,6 +172,8 @@ struct thermal_zone_device {
> int emul_temperature;
> int passive;
> unsigned int forced_passive;
> + bool overheated;
> + bool boost_polling;
> const struct thermal_zone_device_ops *ops;
> const struct thermal_zone_params *tzp;
> struct thermal_governor *governor;

--
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group