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Message-id: <5036D77D.9040308@samsung.com>
Date: Fri, 24 Aug 2012 10:23:09 +0900
From: jonghwa3.lee@...sung.com
To: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Jonghwa Lee <jonghwa3.lee@...sung.com>,
linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
Kyungmin Park <kyungmin.park@...sung.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Mike Turquette <mturquette@...com>,
Xiaoguang Chen <chenxg@...vell.com>
Subject: Re: [PATCH 1/2] devfreq: Add sysfs node for representing frequency
transition information.
Hi, Rafael.
On 2012년 08월 24일 07:21, Rafael J. Wysocki wrote:
> On Thursday, August 16, 2012, Jonghwa Lee wrote:
>> This patch adds sysfs node which can be used to get information of frequency
>> transition. It represents transition table which contains total number of transition of
>> each freqeuncy state and time spent. It is inspired CPUFREQ's status driver.
> First off, please add kerneldoc comments to the new functions.
> It would be good to know what they are intended to do.
Okay, I'll add document for describing what it'll be used to .
> Second, multiline files in sysfs are generally not welcome. Perhaps this
> should go into debugfs instead?
>
> Rafael
Yes, you're right. I didn't know the sysfs constraints until I checked
debugfs kerneldoc.
I'll update it either.
>
>> Signed-off-by: Jonghwa Lee <jonghwa3.lee@...sung.com>
>> ---
>> drivers/devfreq/devfreq.c | 89 +++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/devfreq.h | 9 +++++
>> 2 files changed, 98 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 70c31d4..8b53eaf 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -72,6 +72,41 @@ static struct devfreq *find_device_devfreq(struct device *dev)
>> return ERR_PTR(-ENODEV);
>> }
>>
>> +int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>> +{
>> + int lev;
>> +
>> + for (lev = 0; lev < devfreq->profile->max_state; lev++)
>> + if (freq == devfreq->profile->freq_table[lev])
>> + return lev;
>> +
>> + return -EINVAL;
>> +}
>> +
>> +int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>> +{
>> + int lev, prev_lev;
>> + unsigned long cur_time;
>> +
>> + lev = devfreq_get_freq_level(devfreq, freq);
>> + if (lev < 0)
>> + return lev;
>> +
>> + cur_time = jiffies;
>> + devfreq->time_in_state[lev] +=
>> + cur_time - devfreq->last_stat_updated;
>> + if (freq != devfreq->previous_freq) {
>> + prev_lev = devfreq_get_freq_level(devfreq,
>> + devfreq->previous_freq);
>> + devfreq->trans_table[(prev_lev *
>> + devfreq->profile->max_state) + lev]++;
>> + devfreq->total_trans++;
>> + }
>> + devfreq->last_stat_updated = cur_time;
>> +
>> + return 0;
>> +}
>> +
>> /**
>> * update_devfreq() - Reevaluate the device and configure frequency.
>> * @devfreq: the devfreq instance.
>> @@ -115,6 +150,10 @@ int update_devfreq(struct devfreq *devfreq)
>> err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
>> if (err)
>> return err;
>> + if (devfreq->profile->freq_table)
>> + if (devfreq_update_status(devfreq, freq))
>> + dev_err(&devfreq->dev,
>> + "Couldn't update frequency transition information.\n");
>>
>> devfreq->previous_freq = freq;
>> return err;
>> @@ -390,6 +429,15 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> = msecs_to_jiffies(devfreq->profile->polling_ms);
>> devfreq->nb.notifier_call = devfreq_notifier_call;
>>
>> + devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
>> + devfreq->profile->max_state *
>> + devfreq->profile->max_state,
>> + GFP_KERNEL);
>> + devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
>> + devfreq->profile->max_state,
>> + GFP_KERNEL);
>> + devfreq->last_stat_updated = jiffies;
>> +
>> dev_set_name(&devfreq->dev, dev_name(dev));
>> err = device_register(&devfreq->dev);
>> if (err) {
>> @@ -587,6 +635,46 @@ static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr,
>> return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
>> }
>>
>> +static ssize_t show_trans_table(struct device *dev, struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct devfreq *devfreq = to_devfreq(dev);
>> + ssize_t len;
>> + int i, j, err;
>> +
>> + err = devfreq_update_status(devfreq, devfreq->previous_freq);
>> + if (err)
>> + return 0;
>> +
>> + len = sprintf(buf, " From : To\n");
>> + len += sprintf(buf + len, " :");
>> + for (i = 0; i < devfreq->profile->max_state; i++)
>> + len += sprintf(buf + len, "%8u",
>> + devfreq->profile->freq_table[i]);
>> +
>> + len += sprintf(buf + len, " time(ms)\n");
>> +
>> + for (i = 0; i < devfreq->profile->max_state; i++) {
>> + if (devfreq->profile->freq_table[i]
>> + == devfreq->previous_freq) {
>> + len += sprintf(buf + len, "*");
>> + } else {
>> + len += sprintf(buf + len, " ");
>> + }
>> + len += sprintf(buf + len, "%8u:",
>> + devfreq->profile->freq_table[i]);
>> + for (j = 0; j < devfreq->profile->max_state; j++)
>> + len += sprintf(buf + len, "%8u",
>> + devfreq->trans_table[(i * 3) + j]);
>> + len += sprintf(buf + len, "%10u\n",
>> + jiffies_to_msecs(devfreq->time_in_state[i]));
>> + }
>> +
>> + len += sprintf(buf + len, "Total transition : %u\n",
>> + devfreq->total_trans);
>> + return len;
>> +}
>> +
>> static struct device_attribute devfreq_attrs[] = {
>> __ATTR(governor, S_IRUGO, show_governor, NULL),
>> __ATTR(cur_freq, S_IRUGO, show_freq, NULL),
>> @@ -595,6 +683,7 @@ static struct device_attribute devfreq_attrs[] = {
>> store_polling_interval),
>> __ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq),
>> __ATTR(max_freq, S_IRUGO | S_IWUSR, show_max_freq, store_max_freq),
>> + __ATTR(trans_stat, S_IRUGO, show_trans_table, NULL),
>> { },
>> };
>>
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 281c72a..30dc0d8 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -80,6 +80,9 @@ struct devfreq_dev_profile {
>> int (*get_dev_status)(struct device *dev,
>> struct devfreq_dev_status *stat);
>> void (*exit)(struct device *dev);
>> +
>> + unsigned int *freq_table;
>> + unsigned int max_state;
>> };
>>
>> /**
>> @@ -164,6 +167,12 @@ struct devfreq {
>>
>> unsigned long min_freq;
>> unsigned long max_freq;
>> +
>> + /* information for device freqeuncy transition */
>> + unsigned int total_trans;
>> + unsigned int *trans_table;
>> + unsigned long *time_in_state;
>> + unsigned long last_stat_updated;
>> };
>>
>> #if defined(CONFIG_PM_DEVFREQ)
>>
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