From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eduardo Valentin Subject: Re: [RFC PATCH v6 5/9] thermal: extend the cooling device API to include power information Date: Mon, 5 Jan 2015 17:04:09 -0400 Message-ID: <20150105210403.GC31247@developer> References: <1417806260-9264-1-git-send-email-javi.merino@arm.com> <1417806260-9264-6-git-send-email-javi.merino@arm.com> <20141223151359.GB7350@developer> <20150105153710.GA3042@e104805> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="FsscpQKzF/jJk6ya" Return-path: Content-Disposition: inline In-Reply-To: <20150105153710.GA3042@e104805> Sender: linux-kernel-owner@vger.kernel.org To: Javi Merino Cc: "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Punit Agrawal , "broonie@kernel.org" , Zhang Rui List-Id: linux-pm@vger.kernel.org --FsscpQKzF/jJk6ya Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 > >=20 > > 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. > > >=20 > > > Cc: Zhang Rui > > > Cc: Eduardo Valentin > > > Signed-off-by: Javi Merino > > > --- > > > 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 > > >=20 > > > diff --git a/Documentation/thermal/power_allocator.txt b/Documentatio= n/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 > > > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D > >=20 > > Readers of this file need extra context here, IMO. >=20 > Patch 7 adds text before and after this section that provides that > context. >=20 > > > + > > > +Cooling devices controlled by this governor must supply the addition= al > >=20 > > What governor? the files says power allocator, and the title says, > > cooling device power API... >=20 > 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. >=20 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: > > > + > >=20 > >=20 > >=20 > > > +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. > >=20 > > I believe it would be more helpful if you could provide extra context in > > which the above functions are called, and for what. >=20 > Ok, will do. >=20 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 devic= e_attribute *attr, > > > static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store); > > > #endif/*CONFIG_THERMAL_EMULATION*/ > > > =20 > > > +/** > > > + * power_actor_get_max_power() - get the maximum power that a cdev c= an 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 t= he > > > + * 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 p= ower) > > > +{ > > > + unsigned long state; > > > + > > > + if (!cdev_is_power_actor(cdev)) > > > + return -EINVAL; > > > + > > > + state =3D 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 lon= g *); > > > int (*get_cur_state) (struct thermal_cooling_device *, unsigned lon= g *); > > > int (*set_cur_state) (struct thermal_cooling_device *, unsigned lon= g); > > > + u32 (*get_actual_power) (struct thermal_cooling_device *); > > > + u32 (*state2power) (struct thermal_cooling_device *, unsigned long); > > > + unsigned long (*power2state) (struct thermal_cooling_device *, u32); > > > }; > > > =20 > > > struct thermal_cooling_device { > > > @@ -322,6 +325,15 @@ void thermal_zone_of_sensor_unregister(struct de= vice *dev, > > > } > > > =20 > > > #endif > > > + > > > +static inline bool cdev_is_power_actor(struct thermal_cooling_device= *cdev) > > > +{ > >=20 > > What would happen if one pass cdev =3D=3D NULL? >=20 > 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. >=20 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); > >=20 > > 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.=20 >=20 > 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. >=20 > Cheers, > Javi --FsscpQKzF/jJk6ya Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBAgAGBQJUqvw4AAoJEMLUO4d9pOJWdQoH/ih2uvOj1hlTi2ilM9lWgSD9 PEyRvTVcOCxHfK6wnazZ8lxroQOJI12LaLdhpti59V0gJ+/q0yoOTuHP5Yi2aNmH nDuMxYGtxeJEHYRm8CIo5S8vJFoBh9CBDZX8wQzlL7wS/HhZJnlSyub9YRtlhrgx s4YydvBTH0Rcybn80oC2oSasm5UH/5tqQZZKmJJ6VR6M+7I8ufdyvN3/f3xD+aT7 7uiISmCMM5TllDWGNVzHWwWMtAKgCkQNQihWvhbjsnPmlkyVfNZCEN8MogNaROew psvPuNTWBQNWVpfauwH5HiqEIoezA7WDvYBGSGgrHdHoqdjYuuDGYdMcpY93GTc= =tu2P -----END PGP SIGNATURE----- --FsscpQKzF/jJk6ya--