Messages in this thread Patch in this message |  | | From | Chanwoo Choi <> | Subject | [PATCH] PM / devfreq: Add missing function description and rename static functions | Date | Tue, 7 Jan 2020 10:35:23 +0900 |
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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@samsung.com> --- 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; -- 2.17.1
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