Commit 0dd25a0d authored by Chanwoo Choi's avatar Chanwoo Choi
Browse files

PM / devfreq: Add governor feature flag 



The devfreq governor is able to have the specific flag as follows
in order to implement the specific feature. For example, devfreq allows
user to change the governors on runtime via sysfs interface.
But, if devfreq device uses 'passive' governor, don't allow user to change
the governor. For this case, define the DEVFREQ_GOV_FLAG_IMMUTABLE
and set it to flag of passive governor.

[Definition for governor flag]
- DEVFREQ_GOV_FLAG_IMMUTABLE
  : If immutable flag is set, governor is never changeable to other governors.
- DEVFREQ_GOV_FLAG_IRQ_DRIVEN
  : Devfreq core won't schedule polling work for this governor if value is set.

[Table of governor flag for devfreq governors]
------------------------------------------------------------------------------
                      | simple    | perfor | power | user | passive | tegra30
		      | ondemand  | mance  | save  | space|         |
------------------------------------------------------------------------------
immutable             | X         | X      | X     | X    | O       | O
interrupt_driven      | X(polling)| X      | X     | X    | X       | O (irq)
------------------------------------------------------------------------------

Reviewed-by: default avatarDmitry Osipenko <digetx@gmail.com>
Tested-by: default avatarDmitry Osipenko <digetx@gmail.com>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
parent cab477d0

drivers/devfreq/devfreq.c

+14 −11
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#define CREATE_TRACE_POINTS

#include <trace/events/devfreq.h>



#define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)

#define HZ_PER_KHZ	1000



static struct class *devfreq_class;
@@ -479,7 +480,7 @@ static void devfreq_monitor(struct work_struct *work) 
 */

void devfreq_monitor_start(struct devfreq *devfreq)

{

	if (devfreq->governor->interrupt_driven)

	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))

		return;



	switch (devfreq->profile->timer) {
@@ -509,7 +510,7 @@ EXPORT_SYMBOL(devfreq_monitor_start); 
 */

void devfreq_monitor_stop(struct devfreq *devfreq)

{

	if (devfreq->governor->interrupt_driven)

	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))

		return;



	cancel_delayed_work_sync(&devfreq->work);
@@ -540,7 +541,7 @@ void devfreq_monitor_suspend(struct devfreq *devfreq) 
	devfreq->stop_polling = true;

	mutex_unlock(&devfreq->lock);



	if (devfreq->governor->interrupt_driven)

	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))

		return;



	cancel_delayed_work_sync(&devfreq->work);
@@ -560,12 +561,13 @@ void devfreq_monitor_resume(struct devfreq *devfreq) 
	unsigned long freq;



	mutex_lock(&devfreq->lock);

	if (!devfreq->stop_polling)

		goto out;



	if (devfreq->governor->interrupt_driven)

	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))

		goto out_update;



	if (!devfreq->stop_polling)

		goto out;



	if (!delayed_work_pending(&devfreq->work) &&

			devfreq->profile->polling_ms)

		queue_delayed_work(devfreq_wq, &devfreq->work,
@@ -600,10 +602,10 @@ void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay) 
	mutex_lock(&devfreq->lock);

	devfreq->profile->polling_ms = new_delay;



	if (devfreq->stop_polling)

	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))

		goto out;



	if (devfreq->governor->interrupt_driven)

	if (devfreq->stop_polling)

		goto out;



	/* if new delay is zero, stop polling */
@@ -1370,7 +1372,8 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, 
	if (df->governor == governor) {

		ret = 0;

		goto out;

	} else if (df->governor->immutable || governor->immutable) {

	} else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)

		|| IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {

		ret = -EINVAL;

		goto out;

	}
@@ -1425,7 +1428,7 @@ static ssize_t available_governors_show(struct device *d, 
	 * The devfreq with immutable governor (e.g., passive) shows

	 * only own governor.

	 */

	if (df->governor->immutable) {

	if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {

		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,

				  "%s ", df->governor_name);

	/*
@@ -1436,7 +1439,7 @@ static ssize_t available_governors_show(struct device *d, 
		struct devfreq_governor *governor;



		list_for_each_entry(governor, &devfreq_governor_list, node) {

			if (governor->immutable)

			if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))

				continue;

			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),

					   "%s ", governor->name);

drivers/devfreq/governor.h

+12 −6
Original line number Diff line number Diff line
@@ -25,14 +25,21 @@ 
#define DEVFREQ_MIN_FREQ			0

#define DEVFREQ_MAX_FREQ			ULONG_MAX



/*

 * Definition of the governor feature flags

 * - DEVFREQ_GOV_FLAG_IMMUTABLE

 *   : This governor is never changeable to other governors.

 * - DEVFREQ_GOV_FLAG_IRQ_DRIVEN

 *   : The devfreq won't schedule the work for this governor.

 */

#define DEVFREQ_GOV_FLAG_IMMUTABLE			BIT(0)

#define DEVFREQ_GOV_FLAG_IRQ_DRIVEN			BIT(1)



/**

 * struct devfreq_governor - Devfreq policy governor

 * @node:		list node - contains registered devfreq governors

 * @name:		Governor's name

 * @immutable:		Immutable flag for governor. If the value is 1,

 *			this governor is never changeable to other governor.

 * @interrupt_driven:	Devfreq core won't schedule polling work for this

 *			governor if value is set to 1.

 * @flags:		Governor's feature flags

 * @get_target_freq:	Returns desired operating frequency for the device.

 *			Basically, get_target_freq will run

 *			devfreq_dev_profile.get_dev_status() to get the
@@ -50,8 +57,7 @@ struct devfreq_governor { 
	struct list_head node;



	const char name[DEVFREQ_NAME_LEN];

	const unsigned int immutable;

	const unsigned int interrupt_driven;

	const u64 flags;

	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);

	int (*event_handler)(struct devfreq *devfreq,

				unsigned int event, void *data);

drivers/devfreq/governor_passive.c

+1 −1
Original line number Diff line number Diff line
@@ -158,7 +158,7 @@ static int devfreq_passive_event_handler(struct devfreq *devfreq, 


static struct devfreq_governor devfreq_passive = {

	.name = DEVFREQ_GOV_PASSIVE,

	.immutable = 1,

	.flags = DEVFREQ_GOV_FLAG_IMMUTABLE,

	.get_target_freq = devfreq_passive_get_target_freq,

	.event_handler = devfreq_passive_event_handler,

};

drivers/devfreq/tegra30-devfreq.c

+2 −2
Original line number Diff line number Diff line
@@ -765,10 +765,10 @@ static int tegra_governor_event_handler(struct devfreq *devfreq, 


static struct devfreq_governor tegra_devfreq_governor = {

	.name = "tegra_actmon",

	.flags = DEVFREQ_GOV_FLAG_IMMUTABLE

		| DEVFREQ_GOV_FLAG_IRQ_DRIVEN,

	.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)

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