Hi Lukasz, I has been developed[1] the sysfs attributes for upthreshold and downdifferential. But, I has not yet posted it[1]. I'll post my approach with some changes.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/commit/?h=devfreq-testing&id=e7c59dfb4afebe0c96de54516e9be23d76d96492 On 1/16/21 2:05 AM, Lukasz Luba wrote: > The simple_ondemand devfreq governor is used by quite a few devices, like > GPUs, DSPs, memory controllers, etc. It implements algorithm which tries > to predict the device frequency based on past statistics. There are two > tunables for the algorithm: 'upthreshold' and 'downdifferential'. These > tunables change the behavior of the decision, e.g. how fast to increase > the frequency or how rapidly limit the frequency. These values might be > different based on the application which is currently running, e.g. > different behavior is needed for a game than for web browsing or clean > desktop. The patch exports these two tunables so they can be adjusted > based on current need. There is also a check with the allowed ranges > to make sure the values are correct and safe. > > Signed-off-by: Lukasz Luba <lukasz.l...@arm.com> > --- > drivers/devfreq/governor_simpleondemand.c | 135 ++++++++++++++++++++++ > 1 file changed, 135 insertions(+) > > diff --git a/drivers/devfreq/governor_simpleondemand.c > b/drivers/devfreq/governor_simpleondemand.c > index d57b82a2b570..4b3c182e0a49 100644 > --- a/drivers/devfreq/governor_simpleondemand.c > +++ b/drivers/devfreq/governor_simpleondemand.c > @@ -15,6 +15,7 @@ > /* Default constants for DevFreq-Simple-Ondemand (DFSO) */ > #define DFSO_UPTHRESHOLD (90) > #define DFSO_DOWNDIFFERENCTIAL (5) > +#define DFSO_MAX_VALUE (100) > static int devfreq_simple_ondemand_func(struct devfreq *df, > unsigned long *freq) > { > @@ -84,15 +85,149 @@ static int devfreq_simple_ondemand_func(struct devfreq > *df, > return 0; > } > > +static ssize_t upthreshold_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct devfreq_simple_ondemand_data *data; > + struct devfreq *df = to_devfreq(dev); > + > + if (!df->data) > + return -EINVAL; > + > + data = df->data; > + > + return sprintf(buf, "%d\n", data->upthreshold); > +} > + > +static ssize_t upthreshold_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct devfreq_simple_ondemand_data *data; > + struct devfreq *df = to_devfreq(dev); > + unsigned int value; > + int ret; > + > + if (!df->data) > + return -EINVAL; > + > + data = df->data; > + > + ret = kstrtouint(buf, 10, &value); > + if (ret < 0) > + return -EINVAL; > + > + mutex_lock(&df->lock); > + > + if (value > DFSO_MAX_VALUE || value <= data->downdifferential) { > + mutex_unlock(&df->lock); > + return -EINVAL; > + } > + > + data->upthreshold = value; > + mutex_unlock(&df->lock); > + > + return count; > +} > +static DEVICE_ATTR_RW(upthreshold); > + > +static ssize_t downdifferential_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct devfreq_simple_ondemand_data *data; > + struct devfreq *df = to_devfreq(dev); > + > + if (!df->data) > + return -EINVAL; > + > + data = df->data; > + > + return sprintf(buf, "%d\n", data->downdifferential); > +} > + > +static ssize_t downdifferential_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct devfreq_simple_ondemand_data *data; > + struct devfreq *df = to_devfreq(dev); > + unsigned int value; > + int ret; > + > + if (!df->data) > + return -EINVAL; > + > + data = df->data; > + > + ret = kstrtouint(buf, 10, &value); > + if (ret < 0) > + return -EINVAL; > + > + mutex_lock(&df->lock); > + > + if (value > DFSO_MAX_VALUE || value >= data->upthreshold) { > + mutex_unlock(&df->lock); > + return -EINVAL; > + } > + > + data->downdifferential = value; > + mutex_unlock(&df->lock); > + > + return count; > +} > +static DEVICE_ATTR_RW(downdifferential); > + > +static void devfreq_simple_ondemand_sysfs_setup(struct devfreq *df) > +{ > + struct devfreq_simple_ondemand_data *data; > + int ret; > + > + if (!df->data) { > + /* The memory will be freed automatically */ > + df->data = devm_kzalloc(&df->dev, > + sizeof(struct devfreq_simple_ondemand_data), > + GFP_KERNEL); > + if (!df->data) { > + dev_warn(&df->dev, "Unable to allocate memory"); > + return; > + } > + } > + > + data = df->data; > + > + /* After new allocation setup default values, since they are used */ > + if (!data->upthreshold) > + data->upthreshold = DFSO_UPTHRESHOLD; > + > + if (!data->downdifferential) > + data->downdifferential = DFSO_DOWNDIFFERENCTIAL; > + > + ret = sysfs_create_file(&df->dev.kobj, &dev_attr_upthreshold.attr); > + if (ret < 0) > + dev_warn(&df->dev, "Unable to create 'upthreshold' attr\n"); > + > + ret = sysfs_create_file(&df->dev.kobj, &dev_attr_downdifferential.attr); > + if (ret < 0) > + dev_warn(&df->dev, "Unable to create 'downdifferential' > attr\n"); > +} > + > +static void devfreq_simple_ondemand_sysfs_remove(struct devfreq *df) > +{ > + sysfs_remove_file(&df->dev.kobj, &dev_attr_upthreshold.attr); > + sysfs_remove_file(&df->dev.kobj, &dev_attr_downdifferential.attr); > +} > + > static int devfreq_simple_ondemand_handler(struct devfreq *devfreq, > unsigned int event, void *data) > { > switch (event) { > case DEVFREQ_GOV_START: > devfreq_monitor_start(devfreq); > + devfreq_simple_ondemand_sysfs_setup(devfreq); > break; > > case DEVFREQ_GOV_STOP: > + devfreq_simple_ondemand_sysfs_remove(devfreq); > devfreq_monitor_stop(devfreq); > break; > > -- Best Regards, Chanwoo Choi Samsung Electronics
