Javi, On Mon, Jan 05, 2015 at 03:37:10PM +0000, Javi Merino wrote: > On Tue, Dec 23, 2014 at 03:14:11PM +0000, Eduardo Valentin wrote: > > Hi Javi > > > > On Fri, Dec 05, 2014 at 07:04:16PM +0000, Javi Merino wrote: > > > Add three optional callbacks to the cooling device interface to allow > > > them to express power. In addition to the callbacks, add helpers to > > > identify cooling devices that implement the power cooling device API. > > > > > > Cc: Zhang Rui <rui.zh...@intel.com> > > > Cc: Eduardo Valentin <edubez...@gmail.com> > > > Signed-off-by: Javi Merino <javi.mer...@arm.com> > > > --- > > > Documentation/thermal/power_allocator.txt | 27 ++++++++++++++++++++++ > > > drivers/thermal/thermal_core.c | 38 > > > +++++++++++++++++++++++++++++++ > > > include/linux/thermal.h | 12 ++++++++++ > > > 3 files changed, 77 insertions(+) > > > create mode 100644 Documentation/thermal/power_allocator.txt > > > > > > diff --git a/Documentation/thermal/power_allocator.txt > > > b/Documentation/thermal/power_allocator.txt > > > new file mode 100644 > > > index 000000000000..d3bb79050c27 > > > --- /dev/null > > > +++ b/Documentation/thermal/power_allocator.txt > > > @@ -0,0 +1,27 @@ > > > +Cooling device power API > > > +======================== > > > > Readers of this file need extra context here, IMO. > > Patch 7 adds text before and after this section that provides that > context. > > > > + > > > +Cooling devices controlled by this governor must supply the additional > > > > What governor? the files says power allocator, and the title says, > > cooling device power API... > > Correct, because that's added in the patch that introduces the power > allocator governor. Therefore, it's not a problem for the readers of > this file but for the readers of the patches. I can move this hunk to > patch 7 and introduce all the documentation at once if you think > that's clearer. >
Thinking of the atomicity of each patch/commit, I would prefer you to
move all documentation to a single patch then.
> > > +"power" API in their `cooling_device_ops`. It consists on three ops:
> > > +
> >
> >
> >
> > > +1. u32 get_actual_power(struct thermal_cooling_device *cdev);
> > > +@cdev: The `struct thermal_cooling_device` pointer
> > > +
> > > +`get_actual_power()` returns the power currently consumed by the
> > > +device in milliwatts.
> > > +
> > > +2. u32 state2power(struct thermal_cooling_device *cdev, unsigned long
> > > + state);
> > > +@cdev: The `struct thermal_cooling_device` pointer
> > > +@state: A cooling device state
> > > +
> > > +Convert cooling device state @state into power consumption in
> > > +milliwatts.
> > > +
> > > +3. unsigned long power2state(struct thermal_cooling_device *cdev,
> > > + u32 power);
> > > +@cdev: The `struct thermal_cooling_device` pointer
> > > +@power: power in milliwatts
> > > +
> > > +Calculate a cooling device state that would make the device consume at
> > > +most @power mW.
> >
> > I believe it would be more helpful if you could provide extra context in
> > which the above functions are called, and for what.
>
> Ok, will do.
>
tks.
> > > diff --git a/drivers/thermal/thermal_core.c
> > > b/drivers/thermal/thermal_core.c
> > > index 9021cb72a13a..c490f262ea7f 100644
> > > --- a/drivers/thermal/thermal_core.c
> > > +++ b/drivers/thermal/thermal_core.c
> > > @@ -866,6 +866,44 @@ 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*/
> > >
> > > +/**
> > > + * power_actor_get_max_power() - get the maximum power that a cdev can
> > > consume
> > > + * @cdev: pointer to &thermal_cooling_device
> > > + *
> > > + * Calculate the maximum power consumption in milliwats that the
> > > + * cooling device can currently consume. If @cdev doesn't support the
> > > + * power_actor API, this function returns 0.
> > > + */
> > > +u32 power_actor_get_max_power(struct thermal_cooling_device *cdev)
> > > +{
> > > + if (!cdev_is_power_actor(cdev))
> > > + return 0;
> > > +
> > > + return cdev->ops->state2power(cdev, 0);
> > > +}
> > > +
> > > +/**
> > > + * power_actor_set_power() - limit the maximum power that a cooling
> > > device can consume
> > > + * @cdev: pointer to &thermal_cooling_device
> > > + * @power: the power in milliwatts
> > > + *
> > > + * Set the cooling device to consume at most @power milliwatts.
> > > + *
> > > + * Returns: 0 on success, -EINVAL if the cooling device does not
> > > + * implement the power actor API or -E* for other failures.
> > > + */
> > > +int power_actor_set_power(struct thermal_cooling_device *cdev, u32 power)
> > > +{
> > > + unsigned long state;
> > > +
> > > + if (!cdev_is_power_actor(cdev))
> > > + return -EINVAL;
> > > +
> > > + state = cdev->ops->power2state(cdev, power);
> > > +
> > > + return cdev->ops->set_cur_state(cdev, state);
> > > +}
> > > +
> > > static DEVICE_ATTR(type, 0444, type_show, NULL);
> > > static DEVICE_ATTR(temp, 0444, temp_show, NULL);
> > > static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
> > > diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> > > index 2c14ab1f5c0d..1155457caf52 100644
> > > --- a/include/linux/thermal.h
> > > +++ b/include/linux/thermal.h
> > > @@ -142,6 +142,9 @@ struct thermal_cooling_device_ops {
> > > int (*get_max_state) (struct thermal_cooling_device *, unsigned long *);
> > > int (*get_cur_state) (struct thermal_cooling_device *, unsigned long *);
> > > int (*set_cur_state) (struct thermal_cooling_device *, unsigned long);
> > > + u32 (*get_actual_power) (struct thermal_cooling_device *);
> > > + u32 (*state2power) (struct thermal_cooling_device *, unsigned long);
> > > + unsigned long (*power2state) (struct thermal_cooling_device *, u32);
> > > };
> > >
> > > struct thermal_cooling_device {
> > > @@ -322,6 +325,15 @@ void thermal_zone_of_sensor_unregister(struct device
> > > *dev,
> > > }
> > >
> > > #endif
> > > +
> > > +static inline bool cdev_is_power_actor(struct thermal_cooling_device
> > > *cdev)
> > > +{
> >
> > What would happen if one pass cdev == NULL?
>
> Is it really worth checking it here instead of just making the caller
> pass a valid cdev? There are a number of functions in the thermal
> framework that don't check for valid cdevs or thermal zone pointers
> and I don't see why this one is different.
>
I don't know, maybe we should fix those misbehaving functions then? Can
you please point them out?
> > > + return cdev->ops->get_actual_power && cdev->ops->state2power &&
> > > + cdev->ops->power2state;
> > > +}
> > > +
> > > +u32 power_actor_get_max_power(struct thermal_cooling_device *);
> > > +int power_actor_set_power(struct thermal_cooling_device *, u32);
> > > struct thermal_zone_device *thermal_zone_device_register(const char *,
> > > int, int,
> > > void *, struct thermal_zone_device_ops *,
> > > const struct thermal_zone_params *, int, int);
> >
> > I am assuming the above two new functions are expected to be used also
> > outside thermal core, right? If yes, I'd suggest exporting them.
>
> I don't expect it for the time being. Wouldn't it be preferable to
> export them when its needed instead?
I believe functions in this header are exported. For functions used
inside thermal core and code that goes builtin always, they go into
drivers/thermal/thermal_core.h, and are not exported.
>
> Cheers,
> Javi
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