Re: [RFC][PATCH 1/3] PM /devfreq: add user frequency limits into devfreq struct
From: Chanwoo Choi <cw00.choi@samsung.com>
Date: 2021-02-03 09:56:06
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Subsystem:
device frequency (devfreq), the rest · Maintainers:
MyungJoo Ham, Kyungmin Park, Chanwoo Choi, Linus Torvalds
Hi Lukasz, When accessing the max_freq and min_freq at devfreq-cooling.c, even if can access 'user_max_freq' and 'lock' by using the 'devfreq' instance, I think that the direct access of variables (lock/user_max_freq/user_min_freq) of struct devfreq are not good. Instead, how about using the 'DEVFREQ_TRANSITION_NOTIFIER' notification with following changes of 'struct devfreq_freq'? Also, need to add codes into devfreq_set_target() for initializing 'new_max_freq' and 'new_min_freq' before sending the DEVFREQ_POSTCHANGE notification.
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 147a229056d2..d5726592d362 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h@@ -207,6 +207,8 @@ struct devfreq { struct devfreq_freqs { unsigned long old; unsigned long new; + unsigned long new_max_freq; + unsigned long new_min_freq; };
And I think that new 'user_min_freq'/'user_max_freq' are not necessary. You can get the current max_freq/min_freq by using the following steps: get_freq_range(devfreq, &min_freq, &max_freq); dev_pm_opp_find_freq_floor(pdev, &min_freq); dev_pm_opp_find_freq_floor(pdev, &max_freq); So that you can get the 'max_freq/min_freq' and then initialize the 'freqs.new_max_freq and freqs.new_min_freq' with them as following: in devfreq_set_target() get_freq_range(devfreq, &min_freq, &max_freq); dev_pm_opp_find_freq_floor(pdev, &min_freq); dev_pm_opp_find_freq_floor(pdev, &max_freq); freqs.new_max_freq = min_freq; freqs.new_max_freq = max_freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); On 1/26/21 7:39 PM, Lukasz Luba wrote:
quoted hunk ↗ jump to hunk
The new fields inside devfreq struct allow to check the frequency limits set by the user via sysfs. These limits are important for thermal governor Intelligent Power Allocation (IPA) which needs to know the maximum allowed power consumption of the device. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> --- drivers/devfreq/devfreq.c | 41 +++++++++++++++++++++++++++++++++++---- include/linux/devfreq.h | 4 ++++ 2 files changed, 41 insertions(+), 4 deletions(-)diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 94cc25fd68da..e985a76e5ff3 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c@@ -843,6 +843,9 @@ struct devfreq *devfreq_add_device(struct device *dev, goto err_dev; } + devfreq->user_min_freq = devfreq->scaling_min_freq; + devfreq->user_max_freq = devfreq->scaling_max_freq; + devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); atomic_set(&devfreq->suspend_count, 0);@@ -1513,6 +1516,8 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct devfreq *df = to_devfreq(dev); + struct device *pdev = df->dev.parent; + struct dev_pm_opp *opp; unsigned long value; int ret;@@ -1533,6 +1538,19 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, if (ret < 0) return ret; + if (!value) + value = df->scaling_min_freq; + + opp = dev_pm_opp_find_freq_ceil(pdev, &value); + if (IS_ERR(opp)) + return count; + + dev_pm_opp_put(opp); + + mutex_lock(&df->lock); + df->user_min_freq = value; + mutex_unlock(&df->lock); + return count; }@@ -1554,7 +1572,9 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct devfreq *df = to_devfreq(dev); - unsigned long value; + struct device *pdev = df->dev.parent; + unsigned long value, value_khz; + struct dev_pm_opp *opp; int ret; /*@@ -1579,14 +1599,27 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, * A value of zero means "no limit". */ if (value) - value = DIV_ROUND_UP(value, HZ_PER_KHZ); + value_khz = DIV_ROUND_UP(value, HZ_PER_KHZ); else - value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE; + value_khz = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE; - ret = dev_pm_qos_update_request(&df->user_max_freq_req, value); + ret = dev_pm_qos_update_request(&df->user_max_freq_req, value_khz); if (ret < 0) return ret; + if (!value) + value = df->scaling_max_freq; + + opp = dev_pm_opp_find_freq_floor(pdev, &value); + if (IS_ERR(opp)) + return count; + + dev_pm_opp_put(opp); + + mutex_lock(&df->lock); + df->user_max_freq = value; + mutex_unlock(&df->lock); + return count; }diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index b6d3bae1c74d..147a229056d2 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h@@ -147,6 +147,8 @@ struct devfreq_stats { * touch this. * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) + * @user_min_freq: User's minimum frequency + * @user_max_freq: User's maximum frequency * @scaling_min_freq: Limit minimum frequency requested by OPP interface * @scaling_max_freq: Limit maximum frequency requested by OPP interface * @stop_polling: devfreq polling status of a device.@@ -185,6 +187,8 @@ struct devfreq { struct dev_pm_qos_request user_max_freq_req; unsigned long scaling_min_freq; unsigned long scaling_max_freq; + unsigned long user_min_freq; + unsigned long user_max_freq; bool stop_polling; unsigned long suspend_freq;
-- Best Regards, Chanwoo Choi Samsung Electronics