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Date: Thu, 3 Dec 2020 16:40:55 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Lukasz Luba <lukasz.luba@....com>, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org, dri-devel@...ts.freedesktop.org
Cc: rui.zhang@...el.com, amit.kucheria@...durent.com,
orjan.eide@....com, robh@...nel.org,
alyssa.rosenzweig@...labora.com, steven.price@....com,
airlied@...ux.ie, daniel@...ll.ch, ionela.voinescu@....com
Subject: Re: [PATCH v2 3/5] thermal: devfreq_cooling: add new registration
functions with Energy Model
On 18/11/2020 13:03, Lukasz Luba wrote:
> The Energy Model (EM) framework supports devices such as Devfreq. Create
> new registration functions which automatically register EM for the thermal
> devfreq_cooling devices. This patch prepares the code for coming changes
> which are going to replace old power model with the new EM.
>
> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
> ---
> drivers/thermal/devfreq_cooling.c | 99 ++++++++++++++++++++++++++++++-
> include/linux/devfreq_cooling.h | 22 +++++++
> 2 files changed, 120 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> index 925523694462..b354271742c5 100644
> --- a/drivers/thermal/devfreq_cooling.c
> +++ b/drivers/thermal/devfreq_cooling.c
> @@ -50,6 +50,8 @@ static DEFINE_IDA(devfreq_ida);
> * @capped_state: index to cooling state with in dynamic power budget
> * @req_max_freq: PM QoS request for limiting the maximum frequency
> * of the devfreq device.
> + * @em: Energy Model for the associated Devfreq device
> + * @em_registered: Devfreq cooling registered the EM and should free it.
> */
> struct devfreq_cooling_device {
> int id;
> @@ -63,6 +65,8 @@ struct devfreq_cooling_device {
> u32 res_util;
> int capped_state;
> struct dev_pm_qos_request req_max_freq;
> + struct em_perf_domain *em;
This pointer is not needed, it is in the struct device.
> + bool em_registered;
The boolean em_registered is not needed because of the test in the
function em_dev_unregister_perf_domain():
if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
return;
Logically if the 'em' was not initialized, it must be NULL, the
corresponding struct device was zero-allocated.
> };
>
> static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
> @@ -583,22 +587,115 @@ struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
> }
> EXPORT_SYMBOL_GPL(devfreq_cooling_register);
>
> +/**
> + * devfreq_cooling_em_register_power() - Register devfreq cooling device with
> + * power information and attempt to register Energy Model (EM)
> + * @df: Pointer to devfreq device.
> + * @dfc_power: Pointer to devfreq_cooling_power.
> + * @em_cb: Callback functions providing the data of the EM
> + *
> + * Register a devfreq cooling device and attempt to register Energy Model. The
> + * available OPPs must be registered for the device.
> + *
> + * If @dfc_power is provided, the cooling device is registered with the
> + * power extensions. If @em_cb is provided it will be called for each OPP to
> + * calculate power value and cost. If @em_cb is not provided then simple Energy
> + * Model is going to be used, which requires "dynamic-power-coefficient" a
> + * devicetree property.
> + */
> +struct thermal_cooling_device *
> +devfreq_cooling_em_register_power(struct devfreq *df,
> + struct devfreq_cooling_power *dfc_power,
> + struct em_data_callback *em_cb)
> +{
> + struct thermal_cooling_device *cdev;
> + struct devfreq_cooling_device *dfc;
> + struct device_node *np = NULL;
> + struct device *dev;
> + int nr_opp, ret;
> +
> + if (IS_ERR_OR_NULL(df))
> + return ERR_PTR(-EINVAL);
> +
> + dev = df->dev.parent;
Why the parent ?
> +
> + if (em_cb) {
> + nr_opp = dev_pm_opp_get_opp_count(dev);
> + if (nr_opp <= 0) {
> + dev_err(dev, "No valid OPPs found\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + ret = em_dev_register_perf_domain(dev, nr_opp, em_cb, NULL, false);
> + } else {
> + ret = dev_pm_opp_of_register_em(dev, NULL);
> + }
> +
> + if (ret)
> + dev_warn(dev, "Unable to register EM for devfreq cooling device (%d)\n",
> + ret);
> +
> + if (dev->of_node)
> + np = of_node_get(dev->of_node);
> +
> + cdev = of_devfreq_cooling_register_power(np, df, dfc_power);
> +
> + if (np)
> + of_node_put(np);> +
> + if (IS_ERR_OR_NULL(cdev)) {
> + if (!ret)
> + em_dev_unregister_perf_domain(dev);
> + } else {
> + dfc = cdev->devdata;
> + dfc->em_registered = !ret;
> + }
> +
> + return cdev;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_cooling_em_register_power);
> +
> +/**
> + * devfreq_cooling_em_register() - Register devfreq cooling device together
> + * with Energy Model.
> + * @df: Pointer to devfreq device.
> + * @em_cb: Callback functions providing the data of the Energy Model
> + *
> + * This function attempts to register Energy Model for devfreq device and then
> + * register the devfreq cooling device.
> + */
> +struct thermal_cooling_device *
> +devfreq_cooling_em_register(struct devfreq *df, struct em_data_callback *em_cb)
> +{
> + return devfreq_cooling_em_register_power(df, NULL, em_cb);
> +}
> +EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
> +
> /**
> * devfreq_cooling_unregister() - Unregister devfreq cooling device.
> * @cdev: Pointer to devfreq cooling device to unregister.
> + *
> + * Unregisters devfreq cooling device and related Energy Model if it was
> + * present.
> */
> void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
> {
> struct devfreq_cooling_device *dfc;
> + struct device *dev;
>
> - if (!cdev)
> + if (IS_ERR_OR_NULL(cdev))
Why this additional IS_ERR check ?
> return;
>
> dfc = cdev->devdata;
> + dev = dfc->devfreq->dev.parent;
>
> thermal_cooling_device_unregister(dfc->cdev);
> ida_simple_remove(&devfreq_ida, dfc->id);
> dev_pm_qos_remove_request(&dfc->req_max_freq);
> +
> + if (dfc->em_registered)
> + em_dev_unregister_perf_domain(dev);
> +
As stated before it can be called unconditionally
> kfree(dfc->power_table);
> kfree(dfc->freq_table);
>
> diff --git a/include/linux/devfreq_cooling.h b/include/linux/devfreq_cooling.h
> index 9df2dfca68dd..19868fb922f1 100644
> --- a/include/linux/devfreq_cooling.h
> +++ b/include/linux/devfreq_cooling.h
> @@ -11,6 +11,7 @@
> #define __DEVFREQ_COOLING_H__
>
> #include <linux/devfreq.h>
> +#include <linux/energy_model.h>
> #include <linux/thermal.h>
>
>
> @@ -65,6 +66,13 @@ struct thermal_cooling_device *
> of_devfreq_cooling_register(struct device_node *np, struct devfreq *df);
> struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df);
> void devfreq_cooling_unregister(struct thermal_cooling_device *dfc);
> +struct thermal_cooling_device *
> +devfreq_cooling_em_register_power(struct devfreq *df,
> + struct devfreq_cooling_power *dfc_power,
> + struct em_data_callback *em_cb);
> +struct thermal_cooling_device *
> +devfreq_cooling_em_register(struct devfreq *df,
> + struct em_data_callback *em_cb);
>
> #else /* !CONFIG_DEVFREQ_THERMAL */
>
> @@ -87,6 +95,20 @@ devfreq_cooling_register(struct devfreq *df)
> return ERR_PTR(-EINVAL);
> }
>
> +static inline struct thermal_cooling_device *
> +devfreq_cooling_em_register_power(struct devfreq *df,
> + struct devfreq_cooling_power *dfc_power,
> + struct em_data_callback *em_cb)
> +{
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static inline struct thermal_cooling_device *
> +devfreq_cooling_em_register(struct devfreq *df, struct em_data_callback *em_cb)
> +{
> + return ERR_PTR(-EINVAL);
> +}
> +
> static inline void
> devfreq_cooling_unregister(struct thermal_cooling_device *dfc)
> {
>
--
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