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Subject[PATCH 05/10] thermal: cpu_cooling: Switch to QoS requests instead of cpufreq notifier
Date
The cpufreq core now takes the min/max frequency constraints via QoS
requests and the CPUFREQ_ADJUST notifier shall get removed later on.

Switch over to using the QoS request for maximum frequency constraint
for cpu_cooling driver.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/thermal/cpu_cooling.c | 110 ++++++++--------------------------
1 file changed, 26 insertions(+), 84 deletions(-)

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 4c5db59a619b..391f39776c6a 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -16,6 +16,7 @@
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/pm_opp.h>
+#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/cpu_cooling.h>
@@ -66,8 +67,6 @@ struct time_in_idle {
* @last_load: load measured by the latest call to cpufreq_get_requested_power()
* @cpufreq_state: integer value representing the current state of cpufreq
* cooling devices.
- * @clipped_freq: integer value representing the absolute value of the clipped
- * frequency.
* @max_level: maximum cooling level. One less than total number of valid
* cpufreq frequencies.
* @freq_table: Freq table in descending order of frequencies
@@ -84,12 +83,12 @@ struct cpufreq_cooling_device {
int id;
u32 last_load;
unsigned int cpufreq_state;
- unsigned int clipped_freq;
unsigned int max_level;
struct freq_table *freq_table; /* In descending order */
struct cpufreq_policy *policy;
struct list_head node;
struct time_in_idle *idle_time;
+ struct dev_pm_qos_request qos_req;
};

static DEFINE_IDA(cpufreq_ida);
@@ -118,59 +117,6 @@ static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_cdev,
return level - 1;
}

-/**
- * cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
- * @nb: struct notifier_block * with callback info.
- * @event: value showing cpufreq event for which this function invoked.
- * @data: callback-specific data
- *
- * Callback to hijack the notification on cpufreq policy transition.
- * Every time there is a change in policy, we will intercept and
- * update the cpufreq policy with thermal constraints.
- *
- * Return: 0 (success)
- */
-static int cpufreq_thermal_notifier(struct notifier_block *nb,
- unsigned long event, void *data)
-{
- struct cpufreq_policy *policy = data;
- unsigned long clipped_freq;
- struct cpufreq_cooling_device *cpufreq_cdev;
-
- if (event != CPUFREQ_ADJUST)
- return NOTIFY_DONE;
-
- mutex_lock(&cooling_list_lock);
- list_for_each_entry(cpufreq_cdev, &cpufreq_cdev_list, node) {
- /*
- * A new copy of the policy is sent to the notifier and can't
- * compare that directly.
- */
- if (policy->cpu != cpufreq_cdev->policy->cpu)
- continue;
-
- /*
- * policy->max is the maximum allowed frequency defined by user
- * and clipped_freq is the maximum that thermal constraints
- * allow.
- *
- * If clipped_freq is lower than policy->max, then we need to
- * readjust policy->max.
- *
- * But, if clipped_freq is greater than policy->max, we don't
- * need to do anything.
- */
- clipped_freq = cpufreq_cdev->clipped_freq;
-
- if (policy->max > clipped_freq)
- cpufreq_verify_within_limits(policy, 0, clipped_freq);
- break;
- }
- mutex_unlock(&cooling_list_lock);
-
- return NOTIFY_OK;
-}
-
/**
* update_freq_table() - Update the freq table with power numbers
* @cpufreq_cdev: the cpufreq cooling device in which to update the table
@@ -374,7 +320,6 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
- unsigned int clip_freq;

/* Request state should be less than max_level */
if (WARN_ON(state > cpufreq_cdev->max_level))
@@ -384,13 +329,10 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
if (cpufreq_cdev->cpufreq_state == state)
return 0;

- clip_freq = cpufreq_cdev->freq_table[state].frequency;
cpufreq_cdev->cpufreq_state = state;
- cpufreq_cdev->clipped_freq = clip_freq;
-
- cpufreq_update_policy(cpufreq_cdev->policy->cpu);

- return 0;
+ return dev_pm_qos_update_request(&cpufreq_cdev->qos_req,
+ cpufreq_cdev->freq_table[state].frequency);
}

/**
@@ -554,11 +496,6 @@ static struct thermal_cooling_device_ops cpufreq_power_cooling_ops = {
.power2state = cpufreq_power2state,
};

-/* Notifier for cpufreq policy change */
-static struct notifier_block thermal_cpufreq_notifier_block = {
- .notifier_call = cpufreq_thermal_notifier,
-};
-
static unsigned int find_next_max(struct cpufreq_frequency_table *table,
unsigned int prev_max)
{
@@ -596,9 +533,16 @@ __cpufreq_cooling_register(struct device_node *np,
struct cpufreq_cooling_device *cpufreq_cdev;
char dev_name[THERMAL_NAME_LENGTH];
unsigned int freq, i, num_cpus;
+ struct device *dev;
int ret;
struct thermal_cooling_device_ops *cooling_ops;
- bool first;
+
+ dev = get_cpu_device(policy->cpu);
+ if (unlikely(!dev)) {
+ pr_warn("No cpu device for cpu %d\n", policy->cpu);
+ return ERR_PTR(-ENODEV);
+ }
+

if (IS_ERR_OR_NULL(policy)) {
pr_err("%s: cpufreq policy isn't valid: %p\n", __func__, policy);
@@ -671,25 +615,29 @@ __cpufreq_cooling_register(struct device_node *np,
cooling_ops = &cpufreq_cooling_ops;
}

+ ret = dev_pm_qos_add_request(dev, &cpufreq_cdev->qos_req,
+ DEV_PM_QOS_MAX_FREQUENCY,
+ cpufreq_cdev->freq_table[0].frequency);
+ if (ret < 0) {
+ pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
+ ret);
+ cdev = ERR_PTR(ret);
+ goto remove_ida;
+ }
+
cdev = thermal_of_cooling_device_register(np, dev_name, cpufreq_cdev,
cooling_ops);
if (IS_ERR(cdev))
- goto remove_ida;
-
- cpufreq_cdev->clipped_freq = cpufreq_cdev->freq_table[0].frequency;
+ goto remove_qos_req;

mutex_lock(&cooling_list_lock);
- /* Register the notifier for first cpufreq cooling device */
- first = list_empty(&cpufreq_cdev_list);
list_add(&cpufreq_cdev->node, &cpufreq_cdev_list);
mutex_unlock(&cooling_list_lock);

- if (first)
- cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
- CPUFREQ_POLICY_NOTIFIER);
-
return cdev;

+remove_qos_req:
+ dev_pm_qos_remove_request(&cpufreq_cdev->qos_req);
remove_ida:
ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id);
free_table:
@@ -777,7 +725,6 @@ EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
{
struct cpufreq_cooling_device *cpufreq_cdev;
- bool last;

if (!cdev)
return;
@@ -786,15 +733,10 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)

mutex_lock(&cooling_list_lock);
list_del(&cpufreq_cdev->node);
- /* Unregister the notifier for the last cpufreq cooling device */
- last = list_empty(&cpufreq_cdev_list);
mutex_unlock(&cooling_list_lock);

- if (last)
- cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
- CPUFREQ_POLICY_NOTIFIER);
-
thermal_cooling_device_unregister(cdev);
+ dev_pm_qos_remove_request(&cpufreq_cdev->qos_req);
ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id);
kfree(cpufreq_cdev->idle_time);
kfree(cpufreq_cdev->freq_table);
--
2.21.0.rc0.269.g1a574e7a288b
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