PM / devfreq: add relation of recommended frequency.

The semantics of "target frequency" given to devfreq driver from
devfreq framework has always been interpretted as "at least" or GLB
(greatest lower bound). However, the framework might want the
device driver to limit its max frequency (LUB: least upper bound),
especially if it is given by thermal framework (it's too hot).

Thus, the target fuction should have another parameter to express
whether the framework wants GLB or LUB. And, the additional parameter,
"u32 flags", does it.

With the update, devfreq_recommended_opp() is also updated.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mike Turquette <mturquette@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index a129a7b6bfd121a603f401053bbe0a11865ce03a..70c31d43fff3f1f7c682187c3a3629fce99c1e96 100644 (file)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -83,6 +83,7 @@ int update_devfreq(struct devfreq *devfreq)
 {
        unsigned long freq;
        int err = 0;
+       u32 flags = 0;
 
        if (!mutex_is_locked(&devfreq->lock)) {
                WARN(true, "devfreq->lock must be locked by the caller.\n");
@@ -94,7 +95,24 @@ int update_devfreq(struct devfreq *devfreq)
        if (err)
                return err;
 
-       err = devfreq->profile->target(devfreq->dev.parent, &freq);
+       /*
+        * Adjust the freuqency with user freq and QoS.
+        *
+        * List from the highest proiority
+        * max_freq (probably called by thermal when it's too hot)
+        * min_freq
+        */
+
+       if (devfreq->min_freq && freq < devfreq->min_freq) {
+               freq = devfreq->min_freq;
+               flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
+       }
+       if (devfreq->max_freq && freq > devfreq->max_freq) {
+               freq = devfreq->max_freq;
+               flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
+       }
+
+       err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
        if (err)
                return err;
 
@@ -625,14 +643,30 @@ module_exit(devfreq_exit);
  *                          freq value given to target callback.
  * @dev                The devfreq user device. (parent of devfreq)
  * @freq       The frequency given to target function
+ * @flags      Flags handed from devfreq framework.
  *
  */
-struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq)
+struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq,
+                                   u32 flags)
 {
-       struct opp *opp = opp_find_freq_ceil(dev, freq);
+       struct opp *opp;
 
-       if (opp == ERR_PTR(-ENODEV))
+       if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
+               /* The freq is an upper bound. opp should be lower */
                opp = opp_find_freq_floor(dev, freq);
+
+               /* If not available, use the closest opp */
+               if (opp == ERR_PTR(-ENODEV))
+                       opp = opp_find_freq_ceil(dev, freq);
+       } else {
+               /* The freq is an lower bound. opp should be higher */
+               opp = opp_find_freq_ceil(dev, freq);
+
+               /* If not available, use the closest opp */
+               if (opp == ERR_PTR(-ENODEV))
+                       opp = opp_find_freq_floor(dev, freq);
+       }
+
        return opp;
 }
 

diff --git a/drivers/devfreq/exynos4_bus.c b/drivers/devfreq/exynos4_bus.c
index 590d6865e388e4b52ba41a7c4c2093508b870746..1a361e99965ad26e6f9f93de0d94eed20bf77bad 100644 (file)
--- a/drivers/devfreq/exynos4_bus.c
+++ b/drivers/devfreq/exynos4_bus.c
@@ -619,13 +619,19 @@ static int exynos4_bus_setvolt(struct busfreq_data *data, struct opp *opp,
        return err;
 }
 
-static int exynos4_bus_target(struct device *dev, unsigned long *_freq)
+static int exynos4_bus_target(struct device *dev, unsigned long *_freq,
+                             u32 flags)
 {
        int err = 0;
-       struct busfreq_data *data = dev_get_drvdata(dev);
-       struct opp *opp = devfreq_recommended_opp(dev, _freq);
-       unsigned long old_freq = opp_get_freq(data->curr_opp);
+       struct platform_device *pdev = container_of(dev, struct platform_device,
+                                                   dev);
+       struct busfreq_data *data = platform_get_drvdata(pdev);
+       struct opp *opp = devfreq_recommended_opp(dev, _freq, flags);
        unsigned long freq = opp_get_freq(opp);
+       unsigned long old_freq = opp_get_freq(data->curr_opp);
+
+       if (IS_ERR(opp))
+               return PTR_ERR(opp);
 
        if (old_freq == freq)
                return 0;

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 5862475d05f8a4110400fe29f1eb6f5d73a0596c..281c72a3b9d50d19161c0f6182d38f67991cce8f 100644 (file)
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -44,6 +44,14 @@ struct devfreq_dev_status {
        void *private_data;
 };
 
+/*
+ * The resulting frequency should be at most this. (this bound is the
+ * least upper bound; thus, the resulting freq should be lower or same)
+ * If the flag is not set, the resulting frequency should be at most the
+ * bound (greatest lower bound)
+ */
+#define DEVFREQ_FLAG_LEAST_UPPER_BOUND         0x1
+
 /**
  * struct devfreq_dev_profile - Devfreq's user device profile
  * @initial_freq       The operating frequency when devfreq_add_device() is
@@ -54,6 +62,8 @@ struct devfreq_dev_status {
  *                     higher than any operable frequency, set maximum.
  *                     Before returning, target function should set
  *                     freq at the current frequency.
+ *                     The "flags" parameter's possible values are
+ *                     explained above with "DEVFREQ_FLAG_*" macros.
  * @get_dev_status     The device should provide the current performance
  *                     status to devfreq, which is used by governors.
  * @exit               An optional callback that is called when devfreq
@@ -66,7 +76,7 @@ struct devfreq_dev_profile {
        unsigned long initial_freq;
        unsigned int polling_ms;
 
-       int (*target)(struct device *dev, unsigned long *freq);
+       int (*target)(struct device *dev, unsigned long *freq, u32 flags);
        int (*get_dev_status)(struct device *dev,
                              struct devfreq_dev_status *stat);
        void (*exit)(struct device *dev);
@@ -165,7 +175,7 @@ extern int devfreq_remove_device(struct devfreq *devfreq);
 
 /* Helper functions for devfreq user device driver with OPP. */
 extern struct opp *devfreq_recommended_opp(struct device *dev,
-                                          unsigned long *freq);
+                                          unsigned long *freq, u32 flags);
 extern int devfreq_register_opp_notifier(struct device *dev,
                                         struct devfreq *devfreq);
 extern int devfreq_unregister_opp_notifier(struct device *dev,
@@ -216,7 +226,7 @@ static int devfreq_remove_device(struct devfreq *devfreq)
 }
 
 static struct opp *devfreq_recommended_opp(struct device *dev,
-                                          unsigned long *freq)
+                                          unsigned long *freq, u32 flags)
 {
        return -EINVAL;
 }