*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
-#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/thermal.h>
-#include <linux/platform_device.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/cpu_cooling.h>
/**
- * struct cpufreq_cooling_device
+ * struct cpufreq_cooling_device - data for cooling device with cpufreq
* @id: unique integer value corresponding to each cpufreq_cooling_device
* registered.
- * @cool_dev: thermal_cooling_device pointer to keep track of the the
- * egistered cooling device.
+ * @cool_dev: thermal_cooling_device pointer to keep track of the
+ * registered cooling device.
* @cpufreq_state: integer value representing the current state of cpufreq
* cooling devices.
* @cpufreq_val: integer value representing the absolute value of the clipped
* frequency.
* @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
- * @node: list_head to link all cpufreq_cooling_device together.
*
* This structure is required for keeping information of each
- * cpufreq_cooling_device registered as a list whose head is represented by
- * cooling_cpufreq_list. In order to prevent corruption of this list a
+ * cpufreq_cooling_device registered. In order to prevent corruption of this a
* mutex lock cooling_cpufreq_lock is used.
*/
struct cpufreq_cooling_device {
unsigned int cpufreq_state;
unsigned int cpufreq_val;
struct cpumask allowed_cpus;
- struct list_head node;
};
-static LIST_HEAD(cooling_cpufreq_list);
static DEFINE_IDR(cpufreq_idr);
static DEFINE_MUTEX(cooling_cpufreq_lock);
* get_idr - function to get a unique id.
* @idr: struct idr * handle used to create a id.
* @id: int * value generated by this function.
+ *
+ * This function will populate @id with an unique
+ * id, using the idr API.
+ *
+ * Return: 0 on success, an error code on failure.
*/
static int get_idr(struct idr *idr, int *id)
{
if (unlikely(ret < 0))
return ret;
*id = ret;
+
return 0;
}
/* Below code defines functions to be used for cpufreq as cooling device */
/**
- * is_cpufreq_valid - function to check if a cpu has frequency transition policy.
+ * is_cpufreq_valid - function to check frequency transitioning capability.
* @cpu: cpu for which check is needed.
+ *
+ * This function will check the current state of the system if
+ * it is capable of changing the frequency for a given @cpu.
+ *
+ * Return: 0 if the system is not currently capable of changing
+ * the frequency of given cpu. !0 in case the frequency is changeable.
*/
static int is_cpufreq_valid(int cpu)
{
struct cpufreq_policy policy;
+
return !cpufreq_get_policy(&policy, cpu);
}
+enum cpufreq_cooling_property {
+ GET_LEVEL,
+ GET_FREQ,
+ GET_MAXL,
+};
+
/**
- * get_cpu_frequency - get the absolute value of frequency from level.
- * @cpu: cpu for which frequency is fetched.
- * @level: level of frequency, equals cooling state of cpu cooling device
- * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
+ * get_property - fetch a property of interest for a give cpu.
+ * @cpu: cpu for which the property is required
+ * @input: query parameter
+ * @output: query return
+ * @property: type of query (frequency, level, max level)
+ *
+ * This is the common function to
+ * 1. get maximum cpu cooling states
+ * 2. translate frequency to cooling state
+ * 3. translate cooling state to frequency
+ * Note that the code may be not in good shape
+ * but it is written in this way in order to:
+ * a) reduce duplicate code as most of the code can be shared.
+ * b) make sure the logic is consistent when translating between
+ * cooling states and frequencies.
+ *
+ * Return: 0 on success, -EINVAL when invalid parameters are passed.
*/
-static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
+static int get_property(unsigned int cpu, unsigned long input,
+ unsigned int *output,
+ enum cpufreq_cooling_property property)
{
- int ret = 0, i = 0;
- unsigned long level_index;
- bool descend = false;
+ int i, j;
+ unsigned long max_level = 0, level = 0;
+ unsigned int freq = CPUFREQ_ENTRY_INVALID;
+ int descend = -1;
struct cpufreq_frequency_table *table =
cpufreq_frequency_get_table(cpu);
+
+ if (!output)
+ return -EINVAL;
+
if (!table)
- return ret;
+ return -EINVAL;
- while (table[i].frequency != CPUFREQ_TABLE_END) {
+ for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+ /* ignore invalid entries */
if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
continue;
- /*check if table in ascending or descending order*/
- if ((table[i + 1].frequency != CPUFREQ_TABLE_END) &&
- (table[i + 1].frequency < table[i].frequency)
- && !descend) {
- descend = true;
- }
+ /* ignore duplicate entry */
+ if (freq == table[i].frequency)
+ continue;
+
+ /* get the frequency order */
+ if (freq != CPUFREQ_ENTRY_INVALID && descend != -1)
+ descend = !!(freq > table[i].frequency);
- /*return if level matched and table in descending order*/
- if (descend && i == level)
- return table[i].frequency;
- i++;
+ freq = table[i].frequency;
+ max_level++;
}
- i--;
- if (level > i || descend)
- return ret;
- level_index = i - level;
+ /* get max level */
+ if (property == GET_MAXL) {
+ *output = (unsigned int)max_level;
+ return 0;
+ }
- /*Scan the table in reverse order and match the level*/
- while (i >= 0) {
+ if (property == GET_FREQ)
+ level = descend ? input : (max_level - input - 1);
+
+ for (i = 0, j = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+ /* ignore invalid entry */
if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
continue;
- /*return if level matched*/
- if (i == level_index)
- return table[i].frequency;
- i--;
+
+ /* ignore duplicate entry */
+ if (freq == table[i].frequency)
+ continue;
+
+ /* now we have a valid frequency entry */
+ freq = table[i].frequency;
+
+ if (property == GET_LEVEL && (unsigned int)input == freq) {
+ /* get level by frequency */
+ *output = descend ? j : (max_level - j - 1);
+ return 0;
+ }
+ if (property == GET_FREQ && level == j) {
+ /* get frequency by level */
+ *output = freq;
+ return 0;
+ }
+ j++;
}
- return ret;
+
+ return -EINVAL;
+}
+
+/**
+ * cpufreq_cooling_get_level - for a give cpu, return the cooling level.
+ * @cpu: cpu for which the level is required
+ * @freq: the frequency of interest
+ *
+ * This function will match the cooling level corresponding to the
+ * requested @freq and return it.
+ *
+ * Return: The matched cooling level on success or THERMAL_CSTATE_INVALID
+ * otherwise.
+ */
+unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
+{
+ unsigned int val;
+
+ if (get_property(cpu, (unsigned long)freq, &val, GET_LEVEL))
+ return THERMAL_CSTATE_INVALID;
+
+ return (unsigned long)val;
+}
+EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);
+
+/**
+ * get_cpu_frequency - get the absolute value of frequency from level.
+ * @cpu: cpu for which frequency is fetched.
+ * @level: cooling level
+ *
+ * This function matches cooling level with frequency. Based on a cooling level
+ * of frequency, equals cooling state of cpu cooling device, it will return
+ * the corresponding frequency.
+ * e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
+ *
+ * Return: 0 on error, the corresponding frequency otherwise.
+ */
+static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
+{
+ int ret = 0;
+ unsigned int freq;
+
+ ret = get_property(cpu, level, &freq, GET_FREQ);
+ if (ret)
+ return 0;
+
+ return freq;
}
/**
* @cpufreq_device: cpufreq_cooling_device pointer containing frequency
* clipping data.
* @cooling_state: value of the cooling state.
+ *
+ * Function used to make sure the cpufreq layer is aware of current thermal
+ * limits. The limits are applied by updating the cpufreq policy.
+ *
+ * Return: 0 on success, an error code otherwise (-EINVAL in case wrong
+ * cooling state).
*/
static int cpufreq_apply_cooling(struct cpufreq_cooling_device *cpufreq_device,
- unsigned long cooling_state)
+ unsigned long cooling_state)
{
unsigned int cpuid, clip_freq;
- struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
- unsigned int cpu = cpumask_any(maskPtr);
+ struct cpumask *mask = &cpufreq_device->allowed_cpus;
+ unsigned int cpu = cpumask_any(mask);
/* Check if the old cooling action is same as new cooling action */
cpufreq_device->cpufreq_val = clip_freq;
notify_device = cpufreq_device;
- for_each_cpu(cpuid, maskPtr) {
+ for_each_cpu(cpuid, mask) {
if (is_cpufreq_valid(cpuid))
cpufreq_update_policy(cpuid);
}
* @nb: struct notifier_block * with callback info.
* @event: value showing cpufreq event for which this function invoked.
* @data: callback-specific data
+ *
+ * Callback to highjack 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)
+ unsigned long event, void *data)
{
struct cpufreq_policy *policy = data;
unsigned long max_freq = 0;
if (cpumask_test_cpu(policy->cpu, ¬ify_device->allowed_cpus))
max_freq = notify_device->cpufreq_val;
- /* Never exceed user_policy.max*/
+ /* Never exceed user_policy.max */
if (max_freq > policy->user_policy.max)
max_freq = policy->user_policy.max;
return 0;
}
-/*
- * cpufreq cooling device callback functions are defined below
- */
+/* cpufreq cooling device callback functions are defined below */
/**
* cpufreq_get_max_state - callback function to get the max cooling state.
* @cdev: thermal cooling device pointer.
* @state: fill this variable with the max cooling state.
+ *
+ * Callback for the thermal cooling device to return the cpufreq
+ * max cooling state.
+ *
+ * Return: 0 on success, an error code otherwise.
*/
static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
- struct cpumask *maskPtr = &cpufreq_device->allowed_cpus;
+ struct cpumask *mask = &cpufreq_device->allowed_cpus;
unsigned int cpu;
- struct cpufreq_frequency_table *table;
- unsigned long count = 0;
- int i = 0;
-
- cpu = cpumask_any(maskPtr);
- table = cpufreq_frequency_get_table(cpu);
- if (!table) {
- *state = 0;
- return 0;
- }
+ unsigned int count = 0;
+ int ret;
- for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
- if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
- continue;
- count++;
- }
+ cpu = cpumask_any(mask);
- if (count > 0) {
- *state = --count;
- return 0;
- }
+ ret = get_property(cpu, 0, &count, GET_MAXL);
- return -EINVAL;
+ if (count > 0)
+ *state = count;
+
+ return ret;
}
/**
* cpufreq_get_cur_state - callback function to get the current cooling state.
* @cdev: thermal cooling device pointer.
* @state: fill this variable with the current cooling state.
+ *
+ * Callback for the thermal cooling device to return the cpufreq
+ * current cooling state.
+ *
+ * Return: 0 on success, an error code otherwise.
*/
static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
*state = cpufreq_device->cpufreq_state;
+
return 0;
}
* cpufreq_set_cur_state - callback function to set the current cooling state.
* @cdev: thermal cooling device pointer.
* @state: set this variable to the current cooling state.
+ *
+ * Callback for the thermal cooling device to change the cpufreq
+ * current cooling state.
+ *
+ * Return: 0 on success, an error code otherwise.
*/
static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
/**
* cpufreq_cooling_register - function to create cpufreq cooling device.
* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
+ *
+ * This interface function registers the cpufreq cooling device with the name
+ * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
+ * cooling devices.
+ *
+ * Return: a valid struct thermal_cooling_device pointer on success,
+ * on failure, it returns a corresponding ERR_PTR().
*/
-struct thermal_cooling_device *cpufreq_cooling_register(
- const struct cpumask *clip_cpus)
+struct thermal_cooling_device *
+cpufreq_cooling_register(const struct cpumask *clip_cpus)
{
struct thermal_cooling_device *cool_dev;
struct cpufreq_cooling_device *cpufreq_dev = NULL;
int ret = 0, i;
struct cpufreq_policy policy;
- /*Verify that all the clip cpus have same freq_min, freq_max limit*/
+ /* Verify that all the clip cpus have same freq_min, freq_max limit */
for_each_cpu(i, clip_cpus) {
- /*continue if cpufreq policy not found and not return error*/
+ /* continue if cpufreq policy not found and not return error */
if (!cpufreq_get_policy(&policy, i))
continue;
if (min == 0 && max == 0) {
max = policy.cpuinfo.max_freq;
} else {
if (min != policy.cpuinfo.min_freq ||
- max != policy.cpuinfo.max_freq)
+ max != policy.cpuinfo.max_freq)
return ERR_PTR(-EINVAL);
}
}
cpufreq_dev = kzalloc(sizeof(struct cpufreq_cooling_device),
- GFP_KERNEL);
+ GFP_KERNEL);
if (!cpufreq_dev)
return ERR_PTR(-ENOMEM);
return ERR_PTR(-EINVAL);
}
- sprintf(dev_name, "thermal-cpufreq-%d", cpufreq_dev->id);
+ snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
+ cpufreq_dev->id);
cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
- &cpufreq_cooling_ops);
+ &cpufreq_cooling_ops);
if (!cool_dev) {
release_idr(&cpufreq_idr, cpufreq_dev->id);
kfree(cpufreq_dev);
/* Register the notifier for first cpufreq cooling device */
if (cpufreq_dev_count == 0)
cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
- CPUFREQ_POLICY_NOTIFIER);
+ CPUFREQ_POLICY_NOTIFIER);
cpufreq_dev_count++;
mutex_unlock(&cooling_cpufreq_lock);
+
return cool_dev;
}
-EXPORT_SYMBOL(cpufreq_cooling_register);
+EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
/**
* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
* @cdev: thermal cooling device pointer.
+ *
+ * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
*/
void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
{
cpufreq_dev_count--;
/* Unregister the notifier for the last cpufreq cooling device */
- if (cpufreq_dev_count == 0) {
+ if (cpufreq_dev_count == 0)
cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
- CPUFREQ_POLICY_NOTIFIER);
- }
+ CPUFREQ_POLICY_NOTIFIER);
mutex_unlock(&cooling_cpufreq_lock);
thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
release_idr(&cpufreq_idr, cpufreq_dev->id);
kfree(cpufreq_dev);
}
-EXPORT_SYMBOL(cpufreq_cooling_unregister);
+EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);
projects / firefly-linux-kernel-4.4.55.git / blobdiff