On Thu, Feb 26, 2015 at 05:30:00PM -0400, Eduardo Valentin wrote:
> On Thu, Feb 26, 2015 at 07:00:33PM +0000, Javi Merino wrote:
> > It's useful for tuning to be able to edit thermal_zone_parameters from
> > userspace.  Export them to the thermal_zone sysfs so that they can be
> > easily changed.
> > 
> > Cc: Zhang Rui <[email protected]>
> > Cc: Eduardo Valentin <[email protected]>
> > Signed-off-by: Javi Merino <[email protected]>
> > ---
> >  Documentation/thermal/sysfs-api.txt |  52 +++++++++++++++++
> >  drivers/thermal/thermal_core.c      | 110 
> > ++++++++++++++++++++++++++++++++++++
> >  2 files changed, 162 insertions(+)
> > 
> > diff --git a/Documentation/thermal/sysfs-api.txt 
> > b/Documentation/thermal/sysfs-api.txt
> > index fc7dfe10778b..7d44d7f1a71b 100644
> > --- a/Documentation/thermal/sysfs-api.txt
> > +++ b/Documentation/thermal/sysfs-api.txt
> > @@ -184,6 +184,12 @@ Thermal zone device sys I/F, created once it's 
> > registered:
> >      |---trip_point_[0-*]_type:     Trip point type
> >      |---trip_point_[0-*]_hyst:     Hysteresis value for this trip point
> >      |---emul_temp:         Emulated temperature set node
> > +    |---sustainable_power:      Sustainable dissipatable power
> > +    |---k_po:                   Proportional term during temperature 
> > overshoot
> > +    |---k_pu:                   Proportional term during temperature 
> > undershoot
> > +    |---k_i:                    PID's integral term in the power allocator 
> > gov
> > +    |---k_d:                    PID's derivative term in the power 
> > allocator
> > +    |---integral_cutoff:        Offset above which errors are accumulated
> 
> Can this be under a specific directory?
> 
> I thought of something like
> /sys/class/thermal/thermal_zoneX/governor_params/<gov spec files>
> 
> The above node can be handled by the governor code.
> 
> 
> >  
> >  Thermal cooling device sys I/F, created once it's registered:
> >  /sys/class/thermal/cooling_device[0-*]:
> > @@ -307,6 +313,52 @@ emul_temp
> >       because userland can easily disable the thermal policy by simply
> >       flooding this sysfs node with low temperature values.
> >  
> > +sustainable_power
> > +   An estimate of the sustained power that can be dissipated by
> > +   the thermal zone. Used by the power allocator governor. For
> > +   more information see Documentation/thermal/power_allocator.txt
> > +   Unit: milliwatts
> > +   RW, Optional
> > +
> > +k_po
> > +   The proportional term of the power allocator governor's PID
> > +   controller during temperature overshoot. Temperature overshoot
> > +   is when the current temperature is above the "desired
> > +   temperature" trip point. For more information see
> > +   Documentation/thermal/power_allocator.txt
> > +   RW, Optional
> > +
> > +k_pu
> > +   The proportional term of the power allocator governor's PID
> > +   controller during temperature undershoot. Temperature undershoot
> > +   is when the current temperature is below the "desired
> > +   temperature" trip point. For more information see
> > +   Documentation/thermal/power_allocator.txt
> > +   RW, Optional
> > +
> > +k_i
> > +   The integral term of the power allocator governor's PID
> > +   controller. This term allows the PID controller to compensate
> > +   for long term drift. For more information see
> > +   Documentation/thermal/power_allocator.txt
> > +   RW, Optional
> > +
> > +k_d
> > +   The derivative term of the power allocator governor's PID
> > +   controller. For more information see
> > +   Documentation/thermal/power_allocator.txt
> > +   RW, Optional
> > +
> > +integral_cutoff
> > +   Temperature offset from the desired temperature trip point
> > +   above which the integral term of the power allocator
> > +   governor's PID controller starts accumulating errors. For
> > +   example, if integral_cutoff is 0, then the integral term only
> > +   accumulates error when temperature is above the desired
> > +   temperature trip point. For more information see
> > +   Documentation/thermal/power_allocator.txt
> > +   RW, Optional
> > +
> >  *****************************
> >  * Cooling device attributes *
> >  *****************************
> > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> > index df9ba3bf55dc..228e93f8a146 100644
> > --- a/drivers/thermal/thermal_core.c
> > +++ b/drivers/thermal/thermal_core.c
> > @@ -873,6 +873,111 @@ emul_temp_store(struct device *dev, struct 
> > device_attribute *attr,
> >  static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
> >  #endif/*CONFIG_THERMAL_EMULATION*/
> >  
> > +#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR


What bugged me in the first place was the fact that we are doing this
#ifdef here. But in fact, it is not really necessary, as the parameters
are stored in tzp, and they will be there regardless of the config
status.

> > +
> > +static ssize_t
> > +sustainable_power_show(struct device *dev, struct device_attribute 
> > *devattr,
> > +                  char *buf)
> > +{
> > +   struct thermal_zone_device *tz = to_thermal_zone(dev);
> > +
> > +   if (tz->tzp)
> > +           return sprintf(buf, "%u\n", tz->tzp->sustainable_power);
> > +   else
> > +           return -EIO;
> > +}
> > +
> > +static ssize_t
> > +sustainable_power_store(struct device *dev, struct device_attribute 
> > *devattr,
> > +                   const char *buf, size_t count)
> > +{
> > +   struct thermal_zone_device *tz = to_thermal_zone(dev);
> > +   u32 sustainable_power;
> > +
> > +   if (!tz->tzp)
> > +           return -EIO;
> > +
> > +   if (kstrtou32(buf, 10, &sustainable_power))
> > +           return -EINVAL;
> > +
> > +   tz->tzp->sustainable_power = sustainable_power;
> > +
> > +   return count;
> > +}
> > +static DEVICE_ATTR(sustainable_power, S_IWUSR | S_IRUGO, 
> > sustainable_power_show,
> > +           sustainable_power_store);
> > +
> > +#define create_s32_tzp_attr(name)                                  \
> > +   static ssize_t                                                  \
> > +   name##_show(struct device *dev, struct device_attribute *devattr, \
> > +           char *buf)                                              \
> > +   {                                                               \
> > +   struct thermal_zone_device *tz = to_thermal_zone(dev);          \
> > +                                                                   \
> > +   if (tz->tzp)                                                    \
> > +           return sprintf(buf, "%u\n", tz->tzp->name);             \
> > +   else                                                            \
> > +           return -EIO;                                            \
> > +   }                                                               \
> > +                                                                   \
> > +   static ssize_t                                                  \
> > +   name##_store(struct device *dev, struct device_attribute *devattr, \
> > +           const char *buf, size_t count)                          \
> > +   {                                                               \
> > +           struct thermal_zone_device *tz = to_thermal_zone(dev);  \
> > +           s32 value;                                              \
> > +                                                                   \
> > +           if (!tz->tzp)                                           \
> > +                   return -EIO;                                    \
> > +                                                                   \
> > +           if (kstrtos32(buf, 10, &value))                         \
> > +                   return -EINVAL;                                 \
> > +                                                                   \
> > +           tz->tzp->name = value;                                  \
> > +                                                                   \
> > +           return count;                                           \
> > +   }                                                               \
> > +   static DEVICE_ATTR(name, S_IWUSR | S_IRUGO, name##_show, name##_store)
> > +
> > +create_s32_tzp_attr(k_po);
> > +create_s32_tzp_attr(k_pu);
> > +create_s32_tzp_attr(k_i);
> > +create_s32_tzp_attr(k_d);
> > +create_s32_tzp_attr(integral_cutoff);
> > +#undef create_s32_tzp_attr
> > +
> > +static struct device_attribute *dev_tzp_attrs[] = {
> > +   &dev_attr_sustainable_power,
> > +   &dev_attr_k_po,
> > +   &dev_attr_k_pu,
> > +   &dev_attr_k_i,
> > +   &dev_attr_k_d,
> > +   &dev_attr_integral_cutoff,
> > +};
> > +
> > +static int create_power_allocator_tzp_attrs(struct device *dev)

I would rename this to thermal_create_zone_params_attrs and remove the
ifdefiry. If you are not exposing the complete info under tzp, then make
a comment about it.

> > +{
> > +   int i;
> > +
> > +   for (i = 0; i < ARRAY_SIZE(dev_tzp_attrs); i++) {
> > +           int ret;
> > +           struct device_attribute *dev_attr = dev_tzp_attrs[i];
> > +
> > +           ret = device_create_file(dev, dev_attr);
> > +           if (ret)
> > +                   return ret;
> > +   }
> > +
> > +   return 0;
> > +}
> > +
> > +#else  /* !CONFIG_THERMAL_GOV_POWER_ALLOCATOR */
> > +static int create_power_allocator_tzp_attrs(struct device *dev)
> > +{
> > +   return 0;
> > +}
> > +#endif
> > +
> 
> It is better if this code is not part of thermal_core. The governor
> specific code must be in the governor code. Durga has done a pretty good
> job splitting governor code out of thermal_core.c. I don't think we want
> to get them back.

Unless you really want to expose something that is only inside the
governor data struture, you can ignore the above comment.

> 
> 
> >  /**
> >   * power_actor_get_max_power() - get the maximum power that a cdev can 
> > consume
> >   * @cdev:  pointer to &thermal_cooling_device
> > @@ -1712,6 +1817,11 @@ struct thermal_zone_device 
> > *thermal_zone_device_register(const char *type,
> >     if (result)
> >             goto unregister;
> >  
> > +   /* Add power_allocator specific thermal zone params */
> > +   result = create_power_allocator_tzp_attrs(&tz->device);
> > +   if (result)
> > +           goto unregister;
> 
> Here you could create the governor_params and have a callback from
> governor to populate it.

ditto.

Of course, assuming all we are doing is exposing what is in
thermal_zone_params, which is generic enough to be in thermal_core.c.
> 
> > +
> >     /* Update 'this' zone's governor information */
> >     mutex_lock(&thermal_governor_lock);
> >  
> > -- 
> > 1.9.1
> > 


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