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: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 1b236b9e4d9e8add776a334c1ea79af2ee1e0f69..a862acfe987ea651c57c416b2d1ec3b12d07a747 100644 (file)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -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);

diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
index 02cf876244d6eb9b888ecc4bd3dba3ca92616e3c..7dbb110a869ecea9490704d5f352bb4e920f2ea6 100644 (file)
--- a/drivers/devfreq/governor.h
+++ b/drivers/devfreq/governor.h
@@ -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);

diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index 53a1b15962329f31aed5c75c2228b8c5a8fed057..63332e4a65ae809f254029ee318def50657f6f8f 100644 (file)
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -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,
 };

diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index f5e74c2ede85dd208000b3cf6c6960151d26226a..faa1aecf2a3154bd5eaa48080fbb75267f9ef8da 100644 (file)
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -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)