Re: [PATCH] PM / devfreq: Add missing function description and rename static functions

From: Chanwoo Choi
Date: Wed Jan 08 2020 - 03:41:48 EST

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On 1/8/20 2:03 PM, Chanwoo Choi wrote:
> On 1/7/20 10:35 AM, Chanwoo Choi wrote:
>> Rename internal function name used by devfreq core without 'devfreq_'
>> prefix in order to separate them from the exported functions.
>> And add missing function description for improving the readability.
>>
>> Lastly, add the comments of devfreq_add_device to increase
>> the understanding of behavior of devfreq_add_device.
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
>> ---
>> drivers/devfreq/devfreq.c | 81 +++++++++++++++++++++++++++++++--------
>> 1 file changed, 64 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index acd21345a070..254f11b31824 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -48,7 +48,7 @@ static LIST_HEAD(devfreq_list);
>> static DEFINE_MUTEX(devfreq_list_lock);
>>
>> /**
>> - * find_device_devfreq() - find devfreq struct using device pointer
>> + * find_device_devfreq() - Find devfreq struct using device pointer
>> * @dev: device pointer used to lookup device devfreq.
>> *
>> * Search the list of device devfreqs and return the matched device's
>> @@ -73,6 +73,13 @@ static struct devfreq *find_device_devfreq(struct device *dev)
>> return ERR_PTR(-ENODEV);
>> }
>>
>> +/**
>> + * find_available_min_freq() - Find available min frequency via OPP interface
>> + * @devfreq: the devfreq instance
>> + *
>> + * Find available minimum frequency among the active OPP entries
>> + * because could either enable or disable the frequency by using OPP interface.
>> + */
>> static unsigned long find_available_min_freq(struct devfreq *devfreq)
>> {
>> struct dev_pm_opp *opp;
>> @@ -87,6 +94,13 @@ static unsigned long find_available_min_freq(struct devfreq *devfreq)
>> return min_freq;
>> }
>>
>> +/**
>> + * find_available_max_freq() - Find available max frequency via OPP interface
>> + * @devfreq: the devfreq instance
>> + *
>> + * Find available maximum frequency among the active OPP entries
>> + * because could either enable or disable the frequency by using OPP interface.
>> + */
>> static unsigned long find_available_max_freq(struct devfreq *devfreq)
>> {
>> struct dev_pm_opp *opp;
>> @@ -150,11 +164,11 @@ static void get_freq_range(struct devfreq *devfreq,
>> }
>>
>> /**
>> - * devfreq_get_freq_level() - Lookup freq_table for the frequency
>> + * get_freq_level() - Lookup freq_table for the frequency
>> * @devfreq: the devfreq instance
>> * @freq: the target frequency
>> */
>> -static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>> +static int get_freq_level(struct devfreq *devfreq, unsigned long freq)
>> {
>> int lev;
>>
>> @@ -165,6 +179,13 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>> return -EINVAL;
>> }
>>
>> +/**
>> + * set_freq_table() - Fill out the freq_table of devfreq instance
>> + * @devfreq: the devfreq instance
>> + *
>> + * If freq_table array is NULL, fill out the freq_table array
>> + * by using OPP interface because OPP is mandatory.
>> + */
>> static int set_freq_table(struct devfreq *devfreq)
>> {
>> struct devfreq_dev_profile *profile = devfreq->profile;
>> @@ -218,7 +239,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>> if (!devfreq->previous_freq)
>> goto out;
>>
>> - prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>> + prev_lev = get_freq_level(devfreq, devfreq->previous_freq);
>> if (prev_lev < 0) {
>> ret = prev_lev;
>> goto out;
>> @@ -227,7 +248,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>> devfreq->stats.time_in_state[prev_lev] +=
>> cur_time - devfreq->stats.last_update;
>>
>> - lev = devfreq_get_freq_level(devfreq, freq);
>> + lev = get_freq_level(devfreq, freq);
>> if (lev < 0) {
>> ret = lev;
>> goto out;
>> @@ -246,7 +267,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>> EXPORT_SYMBOL(devfreq_update_status);
>>
>> /**
>> - * find_devfreq_governor() - find devfreq governor from name
>> + * find_devfreq_governor() - Find devfreq governor from name
>> * @name: name of the governor
>> *
>> * Search the list of devfreq governors and return the matched
>> @@ -314,8 +335,17 @@ static struct devfreq_governor *try_then_request_governor(const char *name)
>> return governor;
>> }
>>
>> -static int devfreq_notify_transition(struct devfreq *devfreq,
>> - struct devfreq_freqs *freqs, unsigned int state)
>> +/**
>> + * notify_transition() - Send the transition notification
>> + * @name: name of the governor
>> + * @freqs: the data containing the both old and new frequency
>> + * @state: the kind of notification
>> + *
>> + * Send the transition notification to the registered receivers
>> + * in order to inform the frequency change.
>> + */
>> +static int notify_transition(struct devfreq *devfreq,
>> + struct devfreq_freqs *freqs, unsigned int state)
>> {
>> if (!devfreq)
>> return -EINVAL;
>> @@ -337,8 +367,17 @@ static int devfreq_notify_transition(struct devfreq *devfreq,
>> return 0;
>> }
>>
>> -static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
>> - u32 flags)
>> +/**
>> + * set_target() - Set target frequency of devfreq instance
>> + * @devfreq: the devfreq instance
>> + * @new_freq: the target frequency
>> + * @flags: flags handed from devfreq framework
>> + *
>> + * Set the target frequency of which is decided by governor
>> + * and then is adjusted with constraints.
>> + */
>> +static int set_target(struct devfreq *devfreq,
>> + unsigned long new_freq, u32 flags)
>> {
>> struct devfreq_freqs freqs;
>> unsigned long cur_freq;
>> @@ -351,17 +390,17 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
>>
>> freqs.old = cur_freq;
>> freqs.new = new_freq;
>> - devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
>> + notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
>>
>> err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
>> if (err) {
>> freqs.new = cur_freq;
>> - devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
>> + notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
>> return err;
>> }
>>
>> freqs.new = new_freq;
>> - devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
>> + notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
>>
>> if (devfreq_update_status(devfreq, new_freq))
>> dev_err(&devfreq->dev,
>> @@ -413,7 +452,7 @@ int update_devfreq(struct devfreq *devfreq)
>> flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
>> }
>>
>> - return devfreq_set_target(devfreq, freq, flags);
>> + return set_target(devfreq, freq, flags);
>>
>> }
>> EXPORT_SYMBOL(update_devfreq);
>> @@ -421,7 +460,6 @@ EXPORT_SYMBOL(update_devfreq);
>> /**
>> * devfreq_monitor() - Periodically poll devfreq objects.
>> * @work: the work struct used to run devfreq_monitor periodically.
>> - *
>> */
>> static void devfreq_monitor(struct work_struct *work)
>> {
>> @@ -739,11 +777,13 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> static atomic_t devfreq_no = ATOMIC_INIT(-1);
>> int err = 0;
>>
>> + /* Check the parameter is valid */
>> if (!dev || !profile || !governor_name) {
>> dev_err(dev, "%s: Invalid parameters.\n", __func__);
>> return ERR_PTR(-EINVAL);
>> }
>>
>> + /* Check the device is already added or not */
>> mutex_lock(&devfreq_list_lock);
>> devfreq = find_device_devfreq(dev);
>> mutex_unlock(&devfreq_list_lock);
>> @@ -754,6 +794,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> goto err_out;
>> }
>>
>> + /* Initialize the devfreq instance */
>> devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
>> if (!devfreq) {
>> err = -ENOMEM;
>> @@ -798,6 +839,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
>> atomic_set(&devfreq->suspend_count, 0);
>>
>> + /* Register a device for devfreq instance */
>> dev_set_name(&devfreq->dev, "devfreq%d",
>> atomic_inc_return(&devfreq_no));
>> err = device_register(&devfreq->dev);
>> @@ -807,6 +849,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> goto err_out;
>> }
>>
>> + /* Initialize the statistics of devfreq device behavior */
>> devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
>> array3_size(sizeof(unsigned int),
>> devfreq->profile->max_state,
>> @@ -831,10 +874,12 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> devfreq->stats.total_trans = 0;
>> devfreq->stats.last_update = get_jiffies_64();
>>
>> + /* Initialize notifiers for informing the transition of devfreq */
>> srcu_init_notifier_head(&devfreq->transition_notifier_list);
>>
>> mutex_unlock(&devfreq->lock);
>>
>> + /* Initialize PM QoS for applying the constraints */
>> err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
>> DEV_PM_QOS_MIN_FREQUENCY, 0);
>> if (err < 0)
>> @@ -859,6 +904,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>
>> mutex_lock(&devfreq_list_lock);
>>
>> + /* Find the devfreq governor and start */
>> governor = try_then_request_governor(devfreq->governor_name);
>> if (IS_ERR(governor)) {
>> dev_err(dev, "%s: Unable to find governor for the device\n",
>> @@ -876,6 +922,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> goto err_init;
>> }
>>
>> + /* Add the devfreq instance to global devfreq list finally */
>> list_add(&devfreq->node, &devfreq_list);
>>
>> mutex_unlock(&devfreq_list_lock);
>> @@ -1076,7 +1123,7 @@ int devfreq_suspend_device(struct devfreq *devfreq)
>>
>> if (devfreq->suspend_freq) {
>> mutex_lock(&devfreq->lock);
>> - ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
>> + ret = set_target(devfreq, devfreq->suspend_freq, 0);
>> mutex_unlock(&devfreq->lock);
>> if (ret)
>> return ret;
>> @@ -1106,7 +1153,7 @@ int devfreq_resume_device(struct devfreq *devfreq)
>>
>> if (devfreq->resume_freq) {
>> mutex_lock(&devfreq->lock);
>> - ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
>> + ret = set_target(devfreq, devfreq->resume_freq, 0);
>> mutex_unlock(&devfreq->lock);
>> if (ret)
>> return ret;
>>
>
> Applied it.
>

I'm sorry. Drop this patch because it is not enough to add
the missing description for functions. I'll add the more description
and then resend it.

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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