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Message-ID: <CAPDyKFqBusMHWNHBCMXx6TxFO=8B6ytoyvvSfi14Z=-ahBDV5A@mail.gmail.com>
Date: Tue, 4 Feb 2020 17:54:52 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Thara Gopinath <thara.gopinath@...aro.org>
Cc: Eduardo Valentin <edubezval@...il.com>,
Zhang Rui <rui.zhang@...el.com>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Andy Gross <agross@...nel.org>,
Amit Kucheria <amit.kucheria@...durent.com>,
Mark Rutland <mark.rutland@....com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Linux PM <linux-pm@...r.kernel.org>,
DTML <devicetree@...r.kernel.org>,
linux-arm-msm <linux-arm-msm@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [Patch v4 4/7] thermal: Add generic power domain warming device driver.
On Wed, 20 Nov 2019 at 13:56, Thara Gopinath <thara.gopinath@...aro.org> wrote:
>
> Resources modeled as power domains in linux kenrel can be used to warm the
> SoC(eg. mx power domain on sdm845). To support this feature, introduce a
> generic power domain warming device driver that can be plugged into the
> thermal framework (The thermal framework itself requires further
> modifiction to support a warming device in place of a cooling device.
> Those extensions are not introduced in this patch series).
>
> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
> ---
> v3->v4:
> - Removed late_init hook pd_warming_device_ops.
> - Use of_genpd_add_device instead of pm_genpd_add_device to attach
> device to the generic power domain.
> - Use thermal_of_cooling_device_parent_register to register the
> cooling device so that the device with genpd attached can be
> made parent of the cooling device.
> - With above changes, remove reference to generic_pm_domain in
> pd_warming_device.
>
> drivers/thermal/Kconfig | 10 +++
> drivers/thermal/Makefile | 2 +
> drivers/thermal/pwr_domain_warming.c | 138 +++++++++++++++++++++++++++++++++++
> include/linux/pwr_domain_warming.h | 29 ++++++++
Not sure about what the thermal maintainers think about the naming
here. In the end, it's their call.
However, normally we use "pm_domain_*", rather than "pwr_domain_*",
but maybe just "pd_*" is sufficient here.
> 4 files changed, 179 insertions(+)
> create mode 100644 drivers/thermal/pwr_domain_warming.c
> create mode 100644 include/linux/pwr_domain_warming.h
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 001a21a..0c5c93e 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -187,6 +187,16 @@ config DEVFREQ_THERMAL
>
> If you want this support, you should say Y here.
>
> +config PWR_DOMAIN_WARMING_THERMAL
> + bool "Power Domain based warming device"
> + depends on PM_GENERIC_DOMAINS_OF
> + help
> + This implements the generic power domain based warming
> + mechanism through increasing the performance state of
> + a power domain.
> +
> + If you want this support, you should say Y here.
> +
> config THERMAL_EMULATION
> bool "Thermal emulation mode support"
> help
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 74a37c7..382c64a 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -27,6 +27,8 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL) += clock_cooling.o
> # devfreq cooling
> thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
>
> +thermal_sys-$(CONFIG_PWR_DOMAIN_WARMING_THERMAL) += pwr_domain_warming.o
> +
> # platform thermal drivers
> obj-y += broadcom/
> obj-$(CONFIG_THERMAL_MMIO) += thermal_mmio.o
> diff --git a/drivers/thermal/pwr_domain_warming.c b/drivers/thermal/pwr_domain_warming.c
> new file mode 100644
> index 0000000..40162b9
> --- /dev/null
> +++ b/drivers/thermal/pwr_domain_warming.c
> @@ -0,0 +1,138 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, Linaro Ltd
> + */
> +#include <linux/err.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/slab.h>
> +#include <linux/pwr_domain_warming.h>
> +
> +struct pd_warming_device {
> + struct thermal_cooling_device *cdev;
> + struct device dev;
> + int max_state;
> + int cur_state;
> + bool runtime_resumed;
> +};
> +
> +static int pd_wdev_get_max_state(struct thermal_cooling_device *cdev,
> + unsigned long *state)
> +{
> + struct pd_warming_device *pd_wdev = cdev->devdata;
> +
> + *state = pd_wdev->max_state;
> + return 0;
> +}
> +
> +static int pd_wdev_get_cur_state(struct thermal_cooling_device *cdev,
> + unsigned long *state)
> +{
> + struct pd_warming_device *pd_wdev = cdev->devdata;
> +
> + *state = dev_pm_genpd_get_performance_state(&pd_wdev->dev);
> +
> + return 0;
> +}
> +
> +static int pd_wdev_set_cur_state(struct thermal_cooling_device *cdev,
> + unsigned long state)
> +{
> + struct pd_warming_device *pd_wdev = cdev->devdata;
> + struct device *dev = &pd_wdev->dev;
> + int ret;
> +
> + ret = dev_pm_genpd_set_performance_state(dev, state);
> +
> + if (ret)
> + return ret;
> +
> + if (state && !pd_wdev->runtime_resumed) {
> + ret = pm_runtime_get_sync(dev);
> + pd_wdev->runtime_resumed = true;
> + } else if (!state && pd_wdev->runtime_resumed) {
> + ret = pm_runtime_put(dev);
> + pd_wdev->runtime_resumed = false;
> + }
> +
> + return ret;
> +}
> +
> +static struct thermal_cooling_device_ops pd_warming_device_ops = {
> + .get_max_state = pd_wdev_get_max_state,
> + .get_cur_state = pd_wdev_get_cur_state,
> + .set_cur_state = pd_wdev_set_cur_state,
> +};
> +
> +struct thermal_cooling_device *
> +pwr_domain_warming_register(struct device *parent, char *pd_name, int pd_id)
Maybe rename this to: thermal_of_pd_warming_register()
Moreover, I think you could replace the "struct device *parent", with
a "struct device_node *node" as in-parameter. That's all you need,
right?
> +{
> + struct pd_warming_device *pd_wdev;
> + struct of_phandle_args pd_args;
> + int ret;
> +
> + pd_wdev = kzalloc(sizeof(*pd_wdev), GFP_KERNEL);
> + if (!pd_wdev)
> + return ERR_PTR(-ENOMEM);
> +
> + dev_set_name(&pd_wdev->dev, "%s_warming_dev", pd_name);
Perhaps skip the in-param *pd_name and make use of the suggested
"struct device_node *node", the index and something with "warming...",
when setting the name.
Just an idea, as to simplify for the caller.
> + pd_wdev->dev.parent = parent;
This isn't needed, I think.
> +
> + ret = device_register(&pd_wdev->dev);
> + if (ret)
> + goto error;
> +
> + pd_args.np = parent->of_node;
> + pd_args.args[0] = pd_id;
> + pd_args.args_count = 1;
> +
> + ret = of_genpd_add_device(&pd_args, &pd_wdev->dev);
> +
White space.
> + if (ret)
> + goto error;
> +
> + ret = dev_pm_genpd_performance_state_count(&pd_wdev->dev);
> + if (ret < 0)
> + goto error;
> +
> + pd_wdev->max_state = ret - 1;
> + pm_runtime_enable(&pd_wdev->dev);
> + pd_wdev->runtime_resumed = false;
> +
> + pd_wdev->cdev = thermal_of_cooling_device_parent_register
> + (NULL, parent, pd_name, pd_wdev,
> + &pd_warming_device_ops);
As stated in patch3, I don't get it why you need to use this new API
for "parents".
> + if (IS_ERR(pd_wdev->cdev)) {
> + pr_err("unable to register %s cooling device\n", pd_name);
> + pm_runtime_disable(&pd_wdev->dev);
> + ret = PTR_ERR(pd_wdev->cdev);
> + goto error;
> + }
> +
> + return pd_wdev->cdev;
> +error:
> + put_device(&pd_wdev->dev);
If device_register() succeeds you need to call device_unregister(),
rather than put_device() as a part of the error handling.
> + kfree(pd_wdev);
You need a ->release() callback to manage kfree(), after you called
device_register().
> + return ERR_PTR(ret);
Another thing is missing in the error path, which is to remove the
device for the genpd. I think calling pm_genpd_remove_device() should
work fine here.
> +}
> +EXPORT_SYMBOL_GPL(pwr_domain_warming_register);
> +
> +void pwr_domain_warming_unregister(struct thermal_cooling_device *cdev)
> +{
> + struct pd_warming_device *pd_wdev = cdev->devdata;
> + struct device *dev = &pd_wdev->dev;
> +
> + if (pd_wdev->runtime_resumed) {
> + dev_pm_genpd_set_performance_state(dev, 0);
> + pm_runtime_put(dev);
> + pd_wdev->runtime_resumed = false;
> + }
> + pm_runtime_disable(dev);
> + thermal_cooling_device_unregister(cdev);
> + kfree(pd_wdev);
> +}
> +EXPORT_SYMBOL_GPL(pwr_domain_warming_unregister);
> diff --git a/include/linux/pwr_domain_warming.h b/include/linux/pwr_domain_warming.h
> new file mode 100644
> index 0000000..cb6550d
> --- /dev/null
> +++ b/include/linux/pwr_domain_warming.h
> @@ -0,0 +1,29 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, Linaro Ltd.
> + */
> +#ifndef __PWR_DOMAIN_WARMING_H__
> +#define __PWR_DOMAIN_WARMING_H__
> +
> +#include <linux/pm_domain.h>
> +#include <linux/thermal.h>
> +
> +#ifdef CONFIG_PWR_DOMAIN_WARMING_THERMAL
> +struct thermal_cooling_device *
> +pwr_domain_warming_register(struct device *parent, char *pd_name, int pd_id);
> +
> +void pwr_domain_warming_unregister(struct thermal_cooling_device *cdev);
> +
> +#else
> +static inline struct thermal_cooling_device *
> +pwr_domain_warming_register(struct device *parent, char *pd_name, int pd_id)
> +{
> + return ERR_PTR(-ENOSYS);
> +}
> +
> +static inline void
> +pwr_domain_warming_unregister(struct thermal_cooling_device *cdev)
> +{
> +}
> +#endif /* CONFIG_PWR_DOMAIN_WARMING_THERMAL */
> +#endif /* __PWR_DOMAIN_WARMING_H__ */
> --
> 2.1.4
>
Kind regards
Uffe
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