LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* Re: [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
@ 2015-01-20  4:34 MyungJoo Ham
  2015-01-20  5:29 ` Chanwoo Choi
  0 siblings, 1 reply; 5+ messages in thread
From: MyungJoo Ham @ 2015-01-20  4:34 UTC (permalink / raw)
  To: 최찬우, kgene
  Cc: 박경민,
	rafael.j.wysocki, mark.rutland, ABHILASH KESAVAN, tomasz.figa,
	Krzysztof Kozlowski, Bartlomiej Zolnierkiewicz, robh+dt,
	대인기,
	linux-pm, linux-kernel, linux-arm-kernel, linux-samsung-soc

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=utf-8, Size: 13286 bytes --]

>   
>  This patch add new devfreq_event class for devfreq_event device which provide
> raw data (e.g., memory bus utilization/GPU utilization). This raw data from
> devfreq_event data would be used for the governor of devfreq subsystem.
> - devfreq_event device : Provide raw data for governor of existing devfreq device
> - devfreq device       : Monitor device state and change frequency/voltage of device
>                          using the raw data from devfreq_event device
> 
> The devfreq subsystem support generic DVFS(Dynamic Voltage/Frequency Scaling)
> for Non-CPU Devices. The devfreq device would dertermine current device state
> using various governor (e.g., ondemand, performance, powersave). After completed
> determination of system state, devfreq device would change the frequency/voltage
> of devfreq device according to the result of governor.
> 
> But, devfreq governor must need basic data which indicates current device state.
> Existing devfreq subsystem only consider devfreq device which check current system
> state and determine proper system state using basic data. There is no subsystem
> for device providing basic data to devfreq device.
> 
> The devfreq subsystem must need devfreq_event device(data-provider device) for
> existing devfreq device. So, this patch add new devfreq_event class for
> devfreq_event device which read various basic data(e.g, memory bus utilization,
> GPU utilization) and provide measured data to existing devfreq device through
> standard APIs of devfreq_event class.
> 
> The following description explains the feature of two kind of devfreq class:
> - devfreq class (existing)
>  : devfreq consumer device use raw data from devfreq_event device for
>    determining proper current system state and change voltage/frequency
>    dynamically using various governors.
> 
> - devfreq_event class (new)
>  : Provide measured raw data to devfreq device for governor
> 
> Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---

[]

> +/**
> + * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
> + *				 the enable_count of devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function increase the enable_count and enable the
> + * devfreq-event device. The devfreq-event device should be enabled before
> + * using it by devfreq device.
> + */
> +int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
> +{
> +	int ret = 0;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	mutex_lock(&edev->lock);
> +	if (edev->desc->ops && edev->desc->ops->enable) {
> +		ret = edev->desc->ops->enable(edev);
> +		if (ret < 0)
> +			goto err;
> +	}

Is there any reason to call enable(edev) even when enable_count is already > 0 
while you do not call disable(edev) while enable_count > 0?

I think this may incur errors in the related device drivers.
(e.g., incorrect pairing of clk/runtime-pm/regulator enable/disable
at the device driver side)

> +	edev->enable_count++;
> +err:
> +	mutex_unlock(&edev->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
> +
> +/**
> + * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
> + *				  the enable_count of the devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function decrease the enable_count and disable the
> + * devfreq-event device. After the devfreq-event device is disabled,
> + * devfreq device can't use the devfreq-event device for get/set/reset
> + * operations.
> + */
> +int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
> +{
> +	int ret = 0;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	mutex_lock(&edev->lock);
> +	if (edev->enable_count > 0) {
> +		edev->enable_count--;
> +	} else {
> +		dev_warn(&edev->dev, "unbalanced enable_count\n");
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	if (edev->desc->ops && edev->desc->ops->disable) {
> +		ret = edev->desc->ops->disable(edev);
> +		if (ret < 0) {
> +			edev->enable_count++;
> +			goto err;
> +		}
> +	}

You did it correctly with disable here;
not calling it when it is not required.

> +err:
> +	mutex_unlock(&edev->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
> +

[]
> +EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
[]

> +EXPORT_SYMBOL_GPL(devfreq_event_set_event);
[]

> +
> +/**
> + * devfreq_event_get_event() - Get event and total_event from devfreq-event dev.
> + * @edev	: the devfreq-event device
> + * @edata	: the calculated data of devfreq-event device
> + *
> + * Note that this function get the calculated event data from devfreq-event dev
> + * after stoping the progress of whole sequence of devfreq-event dev.
> + */
> +int devfreq_event_get_event(struct devfreq_event_dev *edev,
> +			    struct devfreq_event_data *edata)
> +{
> +	int ret;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	if (!edev->desc->ops || !edev->desc->ops->get_event)
> +		return -EINVAL;
> +
> +	if (!devfreq_event_is_enabled(edev))
> +		return -EINVAL;
> +
> +	edata->event = edata->total_event = 0;
> +
> +	mutex_lock(&edev->lock);
> +	ret = edev->desc->ops->get_event(edev, edata);
> +	mutex_unlock(&edev->lock);
> +
> +	if ((edata->total_event <= 0)
> +		|| (edata->event > edata->total_event)) {
> +		edata->event = edata->total_event = 0;
> +		ret = -EINVAL;

total_event is unsigned. (cannot be < 0)

Plus, get_event() may already have returned a negative value with
the intention of giving a error different from EINVAL.

I would just simply set total_event = event = 0 if ret < 0.


> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_event);
> +
> +/**
> + * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function stop all operations of devfreq-event dev and reset
> + * the current event data to make the devfreq-event device into initial state.
> + */
> +int devfreq_event_reset_event(struct devfreq_event_dev *edev)
> +{
> +	int ret = 0;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	if (!devfreq_event_is_enabled(edev))
> +		return -EPERM;
> +
> +	mutex_lock(&edev->lock);
> +	if (edev->desc->ops && edev->desc->ops->reset)
> +		ret = edev->desc->ops->reset(edev);
> +	mutex_unlock(&edev->lock);

In the context of the get_event() handling "load",
aren't you supposed to set total_event = event = 0; here?

> +
> +	if (ret < 0)
> +		return -EINVAL;
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
> +
> +/**
> + * devfreq_event_get_drvdata() - Return driver-data of devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function return the driver-data of devfreq-event device.
> + */
> +void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
> +{
> +	return edev->desc->driver_data;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_drvdata);

Looks like you can simply write this in the header file.
(either #define or static inline function)

[]

> +EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
[]
> +EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
[]

> +/**
> + * devfreq_event_add_edev() - Add new devfreq-event device.
> + * @dev		: the device owning the devfreq-event device being created
> + * @desc	: the devfreq-event device's decriptor which include essential
> + *		  data for devfreq-event device.
> + *
> + * Note that this function add new devfreq-event device to devfreq-event class
> + * list and register the device of the devfreq-event device.
> + */
> +struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
> +						struct devfreq_event_desc *desc)
> +{
> +	struct devfreq_event_dev *edev;
> +	static atomic_t event_no = ATOMIC_INIT(0);
> +	int ret;
> +
> +	if (!dev || !desc)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!desc->name || !desc->ops)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!desc->ops->set_event || !desc->ops->get_event)
> +		return ERR_PTR(-EINVAL);
> +
> +	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);

devm_* here? (seeing no free)

> +	if (!edev)
> +		return ERR_PTR(-ENOMEM);
> +
> +	mutex_init(&edev->lock);
> +	edev->desc = desc;
> +	edev->dev.parent = dev;
> +	edev->dev.class = devfreq_event_class;
> +	edev->dev.release = devfreq_event_release_edev;
> +
> +	dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
> +	ret = device_register(&edev->dev);
> +	if (ret < 0) {
> +		put_device(&edev->dev);
> +		return ERR_PTR(ret);
> +	}
> +	dev_set_drvdata(&edev->dev, edev);
> +
> +	INIT_LIST_HEAD(&edev->node);
> +
> +	mutex_lock(&devfreq_event_list_lock);
> +	list_add(&edev->node, &devfreq_event_list);
> +	mutex_unlock(&devfreq_event_list_lock);
> +
> +	return edev;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
> +
> +/**
> + * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
> + * @dev		: the devfreq-event device
> + *
> + * Note that this function remove the registered devfreq-event device.
> + */
> +int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
> +{
> +	if (!edev)
> +		return -EINVAL;
> +
> +	mutex_lock(&devfreq_event_list_lock);
> +	WARN_ON(edev->enable_count);

Let's WARN before mutex_lock();

> +	list_del(&edev->node);
> +	device_unregister(&edev->dev);

Let's unregister after mutex_unlock();

The two lines do not need to be protected by the mutex.

> +	mutex_unlock(&devfreq_event_list_lock);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
> +

[]

> diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
> new file mode 100644
> index 0000000..1ced42c
> --- /dev/null
> +++ b/drivers/devfreq/event/Kconfig
> @@ -0,0 +1,16 @@
> +menuconfig PM_DEVFREQ_EVENT
> +	bool "DEVFREQ-Event device Support"
> +	help
> +	  The devfreq-event device provide the raw data and events which
> +	  indicate the current state of devfreq-event device. The provided
> +	  data from devfreq-event device is used to monitor the state of
> +	  device and determine the suitable size of resource to reduce the
> +	  wasted resource.
> +
> +	  The devfreq-event device can support the various type of events
> +	  (e.g., raw data, utilization, latency, bandwidth). The events
> +	  may be used by devfreq governor and other subsystem.
> +
> +if PM_DEVFREQ_EVENT
> +
> +endif # PM_DEVFREQ_EVENT
> diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
> new file mode 100644
> index 0000000..dc56005
> --- /dev/null
> +++ b/drivers/devfreq/event/Makefile
> @@ -0,0 +1 @@
> +# Exynos DEVFREQ Event Drivers
> diff --git a/include/linux/devfreq-event.h b/include/linux/devfreq-event.h
> new file mode 100644
> index 0000000..b7363f5
> --- /dev/null
> +++ b/include/linux/devfreq-event.h
> @@ -0,0 +1,170 @@
> +/*
> + * devfreq-event: a framework to provide raw data and events of devfreq devices
> + *
> + * Copyright (C) 2014 Samsung Electronics
> + * Author: Chanwoo Choi <cw00.choi@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __LINUX_DEVFREQ_EVENT_H__
> +#define __LINUX_DEVFREQ_EVENT_H__
> +
> +#include <linux/device.h>
> +
> +/**
> + * struct devfreq_event_dev - the devfreq-event device
> + *
> + * @node	: Contain the devfreq-event device that have been registered.
> + * @dev		: the device registered by devfreq-event class. dev.parent is
> + *		  the device using devfreq-event.
> + * @lock	: a mutex to protect accessing devfreq-event.
> + * @enable_count: the number of enable function have been called.
> + * @desc	: the description for devfreq-event device.
> + *
> + * This structure contains devfreq-event device information.
> + */
> +struct devfreq_event_dev {
> +	struct list_head node;
> +
> +	struct device dev;
> +	struct mutex lock;
> +	u32 enable_count;
> +
> +	const struct devfreq_event_desc *desc;
> +};
> +
> +/**
> + * struct devfreq_event_data - the devfreq-event data
> + *
> + * @event	: the load of devfreq-event device for polling period
> + * @total_event	: the total load of devfreq-event device for polling period
> + *
> + * This structure contains the data of devfreq-event device for polling period.
> + */
> +struct devfreq_event_data {
> +	unsigned long event;
> +	unsigned long total_event;
> +};

I would like to rephrase and rename as follows:

+ * @load_count		: load count of devfreq-event device for the given period.
+ * @total_count	: total count of devfreq-event device for the given period.
+ *			each count may represent a clock cycle,
+ *			a time unit (ns/us/...), or anything the device driver wants.
+ *			Generally, utilization is load_count / total_count.

[]


You may already contact me with synchronous methods for more
prompt discussion. :) Your office is not that far from mine.
(Or during lunch, dinner, or beer sessions as well)


Cheers,
MyungJoo

ÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
  2015-01-20  4:34 [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor MyungJoo Ham
@ 2015-01-20  5:29 ` Chanwoo Choi
  0 siblings, 0 replies; 5+ messages in thread
From: Chanwoo Choi @ 2015-01-20  5:29 UTC (permalink / raw)
  To: myungjoo.ham
  Cc: kgene, 박경민,
	rafael.j.wysocki, mark.rutland, ABHILASH KESAVAN, tomasz.figa,
	Krzysztof Kozlowski, Bartlomiej Zolnierkiewicz, robh+dt,
	대인기,
	linux-pm, linux-kernel, linux-arm-kernel, linux-samsung-soc

Dear Myungjoo,

On 01/20/2015 01:34 PM, MyungJoo Ham wrote:
>>   
>>  This patch add new devfreq_event class for devfreq_event device which provide
>> raw data (e.g., memory bus utilization/GPU utilization). This raw data from
>> devfreq_event data would be used for the governor of devfreq subsystem.
>> - devfreq_event device : Provide raw data for governor of existing devfreq device
>> - devfreq device       : Monitor device state and change frequency/voltage of device
>>                          using the raw data from devfreq_event device
>>
>> The devfreq subsystem support generic DVFS(Dynamic Voltage/Frequency Scaling)
>> for Non-CPU Devices. The devfreq device would dertermine current device state
>> using various governor (e.g., ondemand, performance, powersave). After completed
>> determination of system state, devfreq device would change the frequency/voltage
>> of devfreq device according to the result of governor.
>>
>> But, devfreq governor must need basic data which indicates current device state.
>> Existing devfreq subsystem only consider devfreq device which check current system
>> state and determine proper system state using basic data. There is no subsystem
>> for device providing basic data to devfreq device.
>>
>> The devfreq subsystem must need devfreq_event device(data-provider device) for
>> existing devfreq device. So, this patch add new devfreq_event class for
>> devfreq_event device which read various basic data(e.g, memory bus utilization,
>> GPU utilization) and provide measured data to existing devfreq device through
>> standard APIs of devfreq_event class.
>>
>> The following description explains the feature of two kind of devfreq class:
>> - devfreq class (existing)
>>  : devfreq consumer device use raw data from devfreq_event device for
>>    determining proper current system state and change voltage/frequency
>>    dynamically using various governors.
>>
>> - devfreq_event class (new)
>>  : Provide measured raw data to devfreq device for governor
>>
>> Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
>> Cc: Kyungmin Park <kyungmin.park@samsung.com>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>> ---
> 
> []
> 
>> +/**
>> + * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
>> + *				 the enable_count of devfreq-event dev.
>> + * @edev	: the devfreq-event device
>> + *
>> + * Note that this function increase the enable_count and enable the
>> + * devfreq-event device. The devfreq-event device should be enabled before
>> + * using it by devfreq device.
>> + */
>> +int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
>> +{
>> +	int ret = 0;
>> +
>> +	if (!edev || !edev->desc)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&edev->lock);
>> +	if (edev->desc->ops && edev->desc->ops->enable) {
>> +		ret = edev->desc->ops->enable(edev);
>> +		if (ret < 0)
>> +			goto err;
>> +	}
> 
> Is there any reason to call enable(edev) even when enable_count is already > 0 
> while you do not call disable(edev) while enable_count > 0?
> 
> I think this may incur errors in the related device drivers.
> (e.g., incorrect pairing of clk/runtime-pm/regulator enable/disable
> at the device driver side)

You're right. This part has potential errors. I'll fix it as following:
If edev is already enabled, devfreq_event_enable_edev() will just return
without any operation because devfreq-event(edev) can handle only one event
at the same time.
 
	mutex_lock(&edev->lock);
	if (edev->enable_count)
		dev_warn(&edev->dev, "%s is already enabled\n", edev->desc->name);
		ret = -EINVAL;
		goto err;
	}

	if (edev->desc->ops && edev->desc->ops->enable) {		
		ret = edev->desc->ops->enable(edev);
		if (ret < 0)
			goto err;
	}
	edev->enable_count++;
	

> 
>> +	edev->enable_count++;
>> +err:
>> +	mutex_unlock(&edev->lock);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
>> +
>> +/**
>> + * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
>> + *				  the enable_count of the devfreq-event dev.
>> + * @edev	: the devfreq-event device
>> + *
>> + * Note that this function decrease the enable_count and disable the
>> + * devfreq-event device. After the devfreq-event device is disabled,
>> + * devfreq device can't use the devfreq-event device for get/set/reset
>> + * operations.
>> + */
>> +int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
>> +{
>> +	int ret = 0;
>> +
>> +	if (!edev || !edev->desc)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&edev->lock);
>> +	if (edev->enable_count > 0) {
>> +		edev->enable_count--;
>> +	} else {
>> +		dev_warn(&edev->dev, "unbalanced enable_count\n");
>> +		ret = -EINVAL;
>> +		goto err;
>> +	}
>> +
>> +	if (edev->desc->ops && edev->desc->ops->disable) {
>> +		ret = edev->desc->ops->disable(edev);
>> +		if (ret < 0) {
>> +			edev->enable_count++;
>> +			goto err;
>> +		}
>> +	}
> 
> You did it correctly with disable here;
> not calling it when it is not required.

As I explained, I'll fix it as following:

	mutex_lock(&edev->lock);
	if (!edev->enable_count) {
		dev_warn(&edev->dev, "%s is already disabled\n", edev->desc->name);
		ret = -EINVAL;
		goto err;
	}

	if (edev->desc->ops && edev->desc->ops->disable) {
		ret = edev->desc->ops->disable(edev);
		if (ret < 0)
			goto err;		
	}
	edev->enable_count--;

> 
>> +err:
>> +	mutex_unlock(&edev->lock);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
>> +
> 
> []
>> +EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
> []
> 
>> +EXPORT_SYMBOL_GPL(devfreq_event_set_event);
> []
> 
>> +
>> +/**
>> + * devfreq_event_get_event() - Get event and total_event from devfreq-event dev.
>> + * @edev	: the devfreq-event device
>> + * @edata	: the calculated data of devfreq-event device
>> + *
>> + * Note that this function get the calculated event data from devfreq-event dev
>> + * after stoping the progress of whole sequence of devfreq-event dev.
>> + */
>> +int devfreq_event_get_event(struct devfreq_event_dev *edev,
>> +			    struct devfreq_event_data *edata)
>> +{
>> +	int ret;
>> +
>> +	if (!edev || !edev->desc)
>> +		return -EINVAL;
>> +
>> +	if (!edev->desc->ops || !edev->desc->ops->get_event)
>> +		return -EINVAL;
>> +
>> +	if (!devfreq_event_is_enabled(edev))
>> +		return -EINVAL;
>> +
>> +	edata->event = edata->total_event = 0;
>> +
>> +	mutex_lock(&edev->lock);
>> +	ret = edev->desc->ops->get_event(edev, edata);
>> +	mutex_unlock(&edev->lock);
>> +
>> +	if ((edata->total_event <= 0)
>> +		|| (edata->event > edata->total_event)) {
>> +		edata->event = edata->total_event = 0;
>> +		ret = -EINVAL;
> 
> total_event is unsigned. (cannot be < 0)
> 
> Plus, get_event() may already have returned a negative value with
> the intention of giving a error different from EINVAL.
> 
> I would just simply set total_event = event = 0 if ret < 0

OK, I'll fix it as following:

	if (ret < 0)
		edata->total_event = edata->event = 0;
> 
> 
>> +	}
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_get_event);
>> +
>> +/**
>> + * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
>> + * @edev	: the devfreq-event device
>> + *
>> + * Note that this function stop all operations of devfreq-event dev and reset
>> + * the current event data to make the devfreq-event device into initial state.
>> + */
>> +int devfreq_event_reset_event(struct devfreq_event_dev *edev)
>> +{
>> +	int ret = 0;
>> +
>> +	if (!edev || !edev->desc)
>> +		return -EINVAL;
>> +
>> +	if (!devfreq_event_is_enabled(edev))
>> +		return -EPERM;
>> +
>> +	mutex_lock(&edev->lock);
>> +	if (edev->desc->ops && edev->desc->ops->reset)
>> +		ret = edev->desc->ops->reset(edev);
>> +	mutex_unlock(&edev->lock);
> 
> In the context of the get_event() handling "load",
> aren't you supposed to set total_event = event = 0; here?

But, devfreq_event_reset_event() function cannot handle edata instance
because edata is not included in edev. The edata instance is only used in devfreq_event_get_event().

> 
>> +
>> +	if (ret < 0)
>> +		return -EINVAL;
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
>> +
>> +/**
>> + * devfreq_event_get_drvdata() - Return driver-data of devfreq-event dev.
>> + * @edev	: the devfreq-event device
>> + *
>> + * Note that this function return the driver-data of devfreq-event device.
>> + */
>> +void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
>> +{
>> +	return edev->desc->driver_data;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_get_drvdata);
> 
> Looks like you can simply write this in the header file.
> (either #define or static inline function)

OK, I'll modify it by using static inline function.

> 
> []
> 
>> +EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
> []
>> +EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
> []
> 
>> +/**
>> + * devfreq_event_add_edev() - Add new devfreq-event device.
>> + * @dev		: the device owning the devfreq-event device being created
>> + * @desc	: the devfreq-event device's decriptor which include essential
>> + *		  data for devfreq-event device.
>> + *
>> + * Note that this function add new devfreq-event device to devfreq-event class
>> + * list and register the device of the devfreq-event device.
>> + */
>> +struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
>> +						struct devfreq_event_desc *desc)
>> +{
>> +	struct devfreq_event_dev *edev;
>> +	static atomic_t event_no = ATOMIC_INIT(0);
>> +	int ret;
>> +
>> +	if (!dev || !desc)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	if (!desc->name || !desc->ops)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	if (!desc->ops->set_event || !desc->ops->get_event)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
> 
> devm_* here? (seeing no free)

Free edev instance in devfreq_event_release_edev() as following:

	+
	+static void devfreq_event_release_edev(struct device *dev)
	+{
	+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
	+
	+	kfree(edev);
	+}

> 
>> +	if (!edev)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	mutex_init(&edev->lock);
>> +	edev->desc = desc;
>> +	edev->dev.parent = dev;
>> +	edev->dev.class = devfreq_event_class;
>> +	edev->dev.release = devfreq_event_release_edev;
>> +
>> +	dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
>> +	ret = device_register(&edev->dev);
>> +	if (ret < 0) {
>> +		put_device(&edev->dev);
>> +		return ERR_PTR(ret);
>> +	}
>> +	dev_set_drvdata(&edev->dev, edev);
>> +
>> +	INIT_LIST_HEAD(&edev->node);
>> +
>> +	mutex_lock(&devfreq_event_list_lock);
>> +	list_add(&edev->node, &devfreq_event_list);
>> +	mutex_unlock(&devfreq_event_list_lock);
>> +
>> +	return edev;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
>> +
>> +/**
>> + * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
>> + * @dev		: the devfreq-event device
>> + *
>> + * Note that this function remove the registered devfreq-event device.
>> + */
>> +int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
>> +{
>> +	if (!edev)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&devfreq_event_list_lock);
>> +	WARN_ON(edev->enable_count);
> 
> Let's WARN before mutex_lock();

OK.

> 
>> +	list_del(&edev->node);
>> +	device_unregister(&edev->dev);
> 
> Let's unregister after mutex_unlock();
> 
> The two lines do not need to be protected by the mutex.

OK.

> 
>> +	mutex_unlock(&devfreq_event_list_lock);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
>> +
> 
> []
> 
>> diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
>> new file mode 100644
>> index 0000000..1ced42c
>> --- /dev/null
>> +++ b/drivers/devfreq/event/Kconfig
>> @@ -0,0 +1,16 @@
>> +menuconfig PM_DEVFREQ_EVENT
>> +	bool "DEVFREQ-Event device Support"
>> +	help
>> +	  The devfreq-event device provide the raw data and events which
>> +	  indicate the current state of devfreq-event device. The provided
>> +	  data from devfreq-event device is used to monitor the state of
>> +	  device and determine the suitable size of resource to reduce the
>> +	  wasted resource.
>> +
>> +	  The devfreq-event device can support the various type of events
>> +	  (e.g., raw data, utilization, latency, bandwidth). The events
>> +	  may be used by devfreq governor and other subsystem.
>> +
>> +if PM_DEVFREQ_EVENT
>> +
>> +endif # PM_DEVFREQ_EVENT
>> diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
>> new file mode 100644
>> index 0000000..dc56005
>> --- /dev/null
>> +++ b/drivers/devfreq/event/Makefile
>> @@ -0,0 +1 @@
>> +# Exynos DEVFREQ Event Drivers
>> diff --git a/include/linux/devfreq-event.h b/include/linux/devfreq-event.h
>> new file mode 100644
>> index 0000000..b7363f5
>> --- /dev/null
>> +++ b/include/linux/devfreq-event.h
>> @@ -0,0 +1,170 @@
>> +/*
>> + * devfreq-event: a framework to provide raw data and events of devfreq devices
>> + *
>> + * Copyright (C) 2014 Samsung Electronics
>> + * Author: Chanwoo Choi <cw00.choi@samsung.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#ifndef __LINUX_DEVFREQ_EVENT_H__
>> +#define __LINUX_DEVFREQ_EVENT_H__
>> +
>> +#include <linux/device.h>
>> +
>> +/**
>> + * struct devfreq_event_dev - the devfreq-event device
>> + *
>> + * @node	: Contain the devfreq-event device that have been registered.
>> + * @dev		: the device registered by devfreq-event class. dev.parent is
>> + *		  the device using devfreq-event.
>> + * @lock	: a mutex to protect accessing devfreq-event.
>> + * @enable_count: the number of enable function have been called.
>> + * @desc	: the description for devfreq-event device.
>> + *
>> + * This structure contains devfreq-event device information.
>> + */
>> +struct devfreq_event_dev {
>> +	struct list_head node;
>> +
>> +	struct device dev;
>> +	struct mutex lock;
>> +	u32 enable_count;
>> +
>> +	const struct devfreq_event_desc *desc;
>> +};
>> +
>> +/**
>> + * struct devfreq_event_data - the devfreq-event data
>> + *
>> + * @event	: the load of devfreq-event device for polling period
>> + * @total_event	: the total load of devfreq-event device for polling period
>> + *
>> + * This structure contains the data of devfreq-event device for polling period.
>> + */
>> +struct devfreq_event_data {
>> +	unsigned long event;
>> +	unsigned long total_event;
>> +};
> 
> I would like to rephrase and rename as follows:
> 
> + * @load_count		: load count of devfreq-event device for the given period.
> + * @total_count	: total count of devfreq-event device for the given period.
> + *			each count may represent a clock cycle,
> + *			a time unit (ns/us/...), or anything the device driver wants.
> + *			Generally, utilization is load_count / total_count.

OK, I'll change it.

Thanks for your review.

Best Regards,
Chanwoo Choi


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
  2015-01-20  6:59 MyungJoo Ham
@ 2015-01-20  7:25 ` Chanwoo Choi
  0 siblings, 0 replies; 5+ messages in thread
From: Chanwoo Choi @ 2015-01-20  7:25 UTC (permalink / raw)
  To: myungjoo.ham
  Cc: kgene, 박경민,
	rafael.j.wysocki, mark.rutland, ABHILASH KESAVAN, tomasz.figa,
	Krzysztof Kozlowski, Bartlomiej Zolnierkiewicz, robh+dt,
	대인기,
	linux-pm, linux-kernel, linux-arm-kernel, linux-samsung-soc

Dear Myungjoo,

On 01/20/2015 03:59 PM, MyungJoo Ham wrote:
>>  
>> Dear Myungjoo,
>>
>> On 01/20/2015 01:34 PM, MyungJoo Ham wrote:
>>>>   
> []
>>>> +
>>>> +	mutex_lock(&edev->lock);
>>>> +	if (edev->desc->ops && edev->desc->ops->enable) {
>>>> +		ret = edev->desc->ops->enable(edev);
>>>> +		if (ret < 0)
>>>> +			goto err;
>>>> +	}
>>>
>>> Is there any reason to call enable(edev) even when enable_count is already > 0 
>>> while you do not call disable(edev) while enable_count > 0?
>>>
>>> I think this may incur errors in the related device drivers.
>>> (e.g., incorrect pairing of clk/runtime-pm/regulator enable/disable
>>> at the device driver side)
>>
>> You're right. This part has potential errors. I'll fix it as following:
>> If edev is already enabled, devfreq_event_enable_edev() will just return
>> without any operation because devfreq-event(edev) can handle only one event
>> at the same time.
>>
>> 	mutex_lock(&edev->lock);
>> 	if (edev->enable_count)
>> 		dev_warn(&edev->dev, "%s is already enabled\n", edev->desc->name);
>> 		ret = -EINVAL;
>> 		goto err;
>> 	}
>>
>> 	if (edev->desc->ops && edev->desc->ops->enable) {		
>> 		ret = edev->desc->ops->enable(edev);
>> 		if (ret < 0)
>> 			goto err;
>> 	}
>> 	edev->enable_count++;
> 
> No, your suggested modification creates another bug.
> 
> It should not emit "warn" when enable_count > 0 at enable().
> It is a natural behavior from drivers.
> - You may have multiple drivers using edev.
> - You may have multiple threads using edev.

The devfreq-event cannot be used in multiple drivers in current version
If multiple driver set the event to devfreq-event device by using
devfreq_event_set_event() at the same time, previous event will be ignored.

If multiple drivers want to use devfreq-event device at the same time,
I have to implement additional feature.

> 
> Thus, the above 12 lines should be replaced with:
> 
> 	if (edev->desc->ops && edev->desc->ops->enable &&
> 	    edev->enable_count == 0) {
> 		ret = edev->desc->ops->enable(edev);
> 		if (ret < 0)
> 			goto err;
> 	}
> 	edev->enable_count++;
> 
>> 	
>>
>>>
>>>> +	edev->enable_count++;
>>>> +err:
>>>> +	mutex_unlock(&edev->lock);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
>>>> +
>>>> +/**
>>>> + * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
>>>> + *				  the enable_count of the devfreq-event dev.
>>>> + * @edev	: the devfreq-event device
>>>> + *
>>>> + * Note that this function decrease the enable_count and disable the
>>>> + * devfreq-event device. After the devfreq-event device is disabled,
>>>> + * devfreq device can't use the devfreq-event device for get/set/reset
>>>> + * operations.
>>>> + */
>>>> +int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
>>>> +{
>>>> +	int ret = 0;
>>>> +
>>>> +	if (!edev || !edev->desc)
>>>> +		return -EINVAL;
>>>> +
>>>> +	mutex_lock(&edev->lock);
>>>> +	if (edev->enable_count > 0) {
>>>> +		edev->enable_count--;
>>>> +	} else {
>>>> +		dev_warn(&edev->dev, "unbalanced enable_count\n");
>>>> +		ret = -EINVAL;
>>>> +		goto err;
>>>> +	}
>>>> +
>>>> +	if (edev->desc->ops && edev->desc->ops->disable) {
>>>> +		ret = edev->desc->ops->disable(edev);
>>>> +		if (ret < 0) {
>>>> +			edev->enable_count++;
>>>> +			goto err;
>>>> +		}
> 
> Anyway, have you seen other subsystems doing fall-back operations as you've
> done by "edev->enable_count++" here? Or is this your own idea on falling back
> from errors with a disable callback?

I removed "edev->enable_count++" when fail to diable devfreq-event
and modify it as following:

	+int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
	+{
	+	int ret = 0;
	+
	+	if (!edev || !edev->desc)
	+		return -EINVAL;
	+
	+	mutex_lock(&edev->lock);
	+	if (!edev->enable_count) {
	+		dev_warn(&edev->dev,
	+			"%s is already disabled\n", edev->desc->name);
	+		goto err;
	+	}
	+	
	+	if (edev->desc->ops && edev->desc->ops->disable) {
	+		ret = edev->desc->ops->disable(edev);
	+		if (ret < 0)
	+			goto err;
	+	}
	+	edev->enable_count--;
	+err:
	+	mutex_unlock(&edev->lock);
	+
	+	return ret;
	+}
	+EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);

> 
>>>> +	}
>>>
>>> You did it correctly with disable here;
>>> not calling it when it is not required.
> 
> Uh..yeah.. the original patch was incorrect..
> 
>>
>> As I explained, I'll fix it as following:
>>
>> 	mutex_lock(&edev->lock);
>> 	if (!edev->enable_count) {
>> 		dev_warn(&edev->dev, "%s is already disabled\n", edev->desc->name);
>> 		ret = -EINVAL;
>> 		goto err;
>> 	}
>>
>> 	if (edev->desc->ops && edev->desc->ops->disable) {
>> 		ret = edev->desc->ops->disable(edev);
>> 		if (ret < 0)
>> 			goto err;		
>> 	}
>> 	edev->enable_count--;
> 
> Uh.... I'd say it is still incorrect.

I explained it about this problem on the upper.

> 
> 	mutex_lock(&edev->lock);
> 	if (!edev->enable_count) {
> 		dev_warn(&edev->dev, "%s is already disabled\n", edev->desc->name);
> 		ret = -EINVAL;
> 		goto err;
> 	}
> 
> 	edev->enable_count--;
> 	if (edev->desc->ops && edev->desc->ops->disable &&
> 	    !edev->enable_count) {
> 		ret = edev->desc->ops->disable(edev);
> 		if (ret < 0)
> 			goto err;		
> 	}

[snip]

Best Regards,
Chanwoo Choi


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
  2015-01-12 12:34 ` [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor Chanwoo Choi
@ 2015-01-19 10:12   ` Chanwoo Choi
  0 siblings, 0 replies; 5+ messages in thread
From: Chanwoo Choi @ 2015-01-19 10:12 UTC (permalink / raw)
  To: Chanwoo Choi
  Cc: myungjoo.ham, kgene, kyungmin.park, rafael.j.wysocki,
	mark.rutland, a.kesavan, tomasz.figa, k.kozlowski, b.zolnierkie,
	robh+dt, inki.dae, linux-pm, linux-kernel, linux-arm-kernel,
	linux-samsung-soc

Dear Myungjoo,

Following patches need to review from you (DEVFREQ maintainer). Please review these patches.
- [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
- [PATCHv8 2/9] devfreq: event: Add resource-managed function for devfreq-event device

Best Regards,
Chanwoo Choi

On 01/12/2015 09:34 PM, Chanwoo Choi wrote:
> This patch add new devfreq_event class for devfreq_event device which provide
> raw data (e.g., memory bus utilization/GPU utilization). This raw data from
> devfreq_event data would be used for the governor of devfreq subsystem.
> - devfreq_event device : Provide raw data for governor of existing devfreq device
> - devfreq device       : Monitor device state and change frequency/voltage of device
>                          using the raw data from devfreq_event device
> 
> The devfreq subsystem support generic DVFS(Dynamic Voltage/Frequency Scaling)
> for Non-CPU Devices. The devfreq device would dertermine current device state
> using various governor (e.g., ondemand, performance, powersave). After completed
> determination of system state, devfreq device would change the frequency/voltage
> of devfreq device according to the result of governor.
> 
> But, devfreq governor must need basic data which indicates current device state.
> Existing devfreq subsystem only consider devfreq device which check current system
> state and determine proper system state using basic data. There is no subsystem
> for device providing basic data to devfreq device.
> 
> The devfreq subsystem must need devfreq_event device(data-provider device) for
> existing devfreq device. So, this patch add new devfreq_event class for
> devfreq_event device which read various basic data(e.g, memory bus utilization,
> GPU utilization) and provide measured data to existing devfreq device through
> standard APIs of devfreq_event class.
> 
> The following description explains the feature of two kind of devfreq class:
> - devfreq class (existing)
>  : devfreq consumer device use raw data from devfreq_event device for
>    determining proper current system state and change voltage/frequency
>    dynamically using various governors.
> 
> - devfreq_event class (new)
>  : Provide measured raw data to devfreq device for governor
> 
> Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
>  drivers/devfreq/Kconfig         |   2 +
>  drivers/devfreq/Makefile        |   6 +-
>  drivers/devfreq/devfreq-event.c | 448 ++++++++++++++++++++++++++++++++++++++++
>  drivers/devfreq/event/Kconfig   |  16 ++
>  drivers/devfreq/event/Makefile  |   1 +
>  include/linux/devfreq-event.h   | 170 +++++++++++++++
>  6 files changed, 642 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/devfreq/devfreq-event.c
>  create mode 100644 drivers/devfreq/event/Kconfig
>  create mode 100644 drivers/devfreq/event/Makefile
>  create mode 100644 include/linux/devfreq-event.h
> 
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index faf4e70..21f8f17 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -87,4 +87,6 @@ config ARM_EXYNOS5_BUS_DEVFREQ
>  	  It reads PPMU counters of memory controllers and adjusts the
>  	  operating frequencies and voltages with OPP support.
>  
> +source "drivers/devfreq/event/Kconfig"
> +
>  endif # PM_DEVFREQ
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 16138c9..c449336 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -1,4 +1,5 @@
> -obj-$(CONFIG_PM_DEVFREQ)	+= devfreq.o
> +obj-$(CONFIG_PM_DEVFREQ)		+= devfreq.o
> +obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= devfreq-event.o
>  obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)	+= governor_simpleondemand.o
>  obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
>  obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
> @@ -7,3 +8,6 @@ obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
>  # DEVFREQ Drivers
>  obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/
>  obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ)	+= exynos/
> +
> +# DEVFREQ Event Drivers
> +obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= event/
> diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
> new file mode 100644
> index 0000000..9ba5ba4
> --- /dev/null
> +++ b/drivers/devfreq/devfreq-event.c
> @@ -0,0 +1,448 @@
> +/*
> + * devfreq-event: a framework to provide raw data and events of devfreq devices
> + *
> + * Copyright (C) 2014 Samsung Electronics
> + * Author: Chanwoo Choi <cw00.choi@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This driver is based on drivers/devfreq/devfreq.c.
> + */
> +
> +#include <linux/devfreq-event.h>
> +#include <linux/kernel.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/list.h>
> +#include <linux/of.h>
> +
> +static struct class *devfreq_event_class;
> +
> +/* The list of all devfreq event list */
> +static LIST_HEAD(devfreq_event_list);
> +static DEFINE_MUTEX(devfreq_event_list_lock);
> +
> +#define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
> +
> +/**
> + * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
> + *				 the enable_count of devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function increase the enable_count and enable the
> + * devfreq-event device. The devfreq-event device should be enabled before
> + * using it by devfreq device.
> + */
> +int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
> +{
> +	int ret = 0;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	mutex_lock(&edev->lock);
> +	if (edev->desc->ops && edev->desc->ops->enable) {
> +		ret = edev->desc->ops->enable(edev);
> +		if (ret < 0)
> +			goto err;
> +	}
> +	edev->enable_count++;
> +err:
> +	mutex_unlock(&edev->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
> +
> +/**
> + * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
> + *				  the enable_count of the devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function decrease the enable_count and disable the
> + * devfreq-event device. After the devfreq-event device is disabled,
> + * devfreq device can't use the devfreq-event device for get/set/reset
> + * operations.
> + */
> +int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
> +{
> +	int ret = 0;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	mutex_lock(&edev->lock);
> +	if (edev->enable_count > 0) {
> +		edev->enable_count--;
> +	} else {
> +		dev_warn(&edev->dev, "unbalanced enable_count\n");
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	if (edev->desc->ops && edev->desc->ops->disable) {
> +		ret = edev->desc->ops->disable(edev);
> +		if (ret < 0) {
> +			edev->enable_count++;
> +			goto err;
> +		}
> +	}
> +err:
> +	mutex_unlock(&edev->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
> +
> +/**
> + * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
> + *				not.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function check whether devfreq-event dev is enabled or not.
> + * If return true, the devfreq-event dev is enabeld. If return false, the
> + * devfreq-event dev is disabled.
> + */
> +bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
> +{
> +	bool enabled = false;
> +
> +	if (!edev || !edev->desc)
> +		return enabled;
> +
> +	mutex_lock(&edev->lock);
> +
> +	if (edev->enable_count > 0)
> +		enabled = true;
> +
> +	mutex_unlock(&edev->lock);
> +
> +	return enabled;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
> +
> +/**
> + * devfreq_event_set_event() - Set event to devfreq-event dev to start.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function set the event to the devfreq-event device to start
> + * for getting the event data which could be various event type.
> + */
> +int devfreq_event_set_event(struct devfreq_event_dev *edev)
> +{
> +	int ret;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	if (!edev->desc->ops || !edev->desc->ops->set_event)
> +		return -EINVAL;
> +
> +	if (!devfreq_event_is_enabled(edev))
> +		return -EPERM;
> +
> +	mutex_lock(&edev->lock);
> +	ret = edev->desc->ops->set_event(edev);
> +	mutex_unlock(&edev->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_set_event);
> +
> +/**
> + * devfreq_event_get_event() - Get event and total_event from devfreq-event dev.
> + * @edev	: the devfreq-event device
> + * @edata	: the calculated data of devfreq-event device
> + *
> + * Note that this function get the calculated event data from devfreq-event dev
> + * after stoping the progress of whole sequence of devfreq-event dev.
> + */
> +int devfreq_event_get_event(struct devfreq_event_dev *edev,
> +			    struct devfreq_event_data *edata)
> +{
> +	int ret;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	if (!edev->desc->ops || !edev->desc->ops->get_event)
> +		return -EINVAL;
> +
> +	if (!devfreq_event_is_enabled(edev))
> +		return -EINVAL;
> +
> +	edata->event = edata->total_event = 0;
> +
> +	mutex_lock(&edev->lock);
> +	ret = edev->desc->ops->get_event(edev, edata);
> +	mutex_unlock(&edev->lock);
> +
> +	if ((edata->total_event <= 0)
> +		|| (edata->event > edata->total_event)) {
> +		edata->event = edata->total_event = 0;
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_event);
> +
> +/**
> + * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function stop all operations of devfreq-event dev and reset
> + * the current event data to make the devfreq-event device into initial state.
> + */
> +int devfreq_event_reset_event(struct devfreq_event_dev *edev)
> +{
> +	int ret = 0;
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	if (!devfreq_event_is_enabled(edev))
> +		return -EPERM;
> +
> +	mutex_lock(&edev->lock);
> +	if (edev->desc->ops && edev->desc->ops->reset)
> +		ret = edev->desc->ops->reset(edev);
> +	mutex_unlock(&edev->lock);
> +
> +	if (ret < 0)
> +		return -EINVAL;
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
> +
> +/**
> + * devfreq_event_get_drvdata() - Return driver-data of devfreq-event dev.
> + * @edev	: the devfreq-event device
> + *
> + * Note that this function return the driver-data of devfreq-event device.
> + */
> +void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
> +{
> +	return edev->desc->driver_data;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_drvdata);
> +
> +/**
> + * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
> + *					 devicetree.
> + * @dev		: the pointer to the given device
> + * @index	: the index into list of devfreq-event device
> + *
> + * Note that this function return the pointer of devfreq-event device.
> + */
> +struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
> +						      int index)
> +{
> +	struct device_node *node;
> +	struct devfreq_event_dev *edev;
> +
> +	if (!dev->of_node) {
> +		dev_err(dev, "device does not have a device node entry\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	node = of_parse_phandle(dev->of_node, "devfreq-events", index);
> +	if (!node) {
> +		dev_err(dev, "failed to get phandle in %s node\n",
> +			dev->of_node->full_name);
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	mutex_lock(&devfreq_event_list_lock);
> +	list_for_each_entry(edev, &devfreq_event_list, node) {
> +		if (!strcmp(edev->desc->name, node->name))
> +			goto out;
> +	}
> +	edev = NULL;
> +out:
> +	mutex_unlock(&devfreq_event_list_lock);
> +
> +	if (!edev) {
> +		dev_err(dev, "unable to get devfreq-event device : %s\n",
> +			node->name);
> +		of_node_put(node);
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	of_node_put(node);
> +
> +	return edev;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
> +
> +/**
> + * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
> + * @dev		: the pointer to the given device
> + *
> + * Note that this function return the count of devfreq-event devices.
> + */
> +int devfreq_event_get_edev_count(struct device *dev)
> +{
> +	int count;
> +
> +	if (!dev->of_node) {
> +		dev_err(dev, "device does not have a device node entry\n");
> +		return -EINVAL;
> +	}
> +
> +	count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
> +						sizeof(u32));
> +	if (count < 0 ) {
> +		dev_err(dev,
> +			"failed to get the count of devfreq-event in %s node\n",
> +			dev->of_node->full_name);
> +		return count;
> +	}
> +
> +	return count;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
> +
> +static void devfreq_event_release_edev(struct device *dev)
> +{
> +	struct devfreq_event_dev *edev = to_devfreq_event(dev);
> +
> +	kfree(edev);
> +}
> +
> +/**
> + * devfreq_event_add_edev() - Add new devfreq-event device.
> + * @dev		: the device owning the devfreq-event device being created
> + * @desc	: the devfreq-event device's decriptor which include essential
> + *		  data for devfreq-event device.
> + *
> + * Note that this function add new devfreq-event device to devfreq-event class
> + * list and register the device of the devfreq-event device.
> + */
> +struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
> +						struct devfreq_event_desc *desc)
> +{
> +	struct devfreq_event_dev *edev;
> +	static atomic_t event_no = ATOMIC_INIT(0);
> +	int ret;
> +
> +	if (!dev || !desc)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!desc->name || !desc->ops)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!desc->ops->set_event || !desc->ops->get_event)
> +		return ERR_PTR(-EINVAL);
> +
> +	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
> +	if (!edev)
> +		return ERR_PTR(-ENOMEM);
> +
> +	mutex_init(&edev->lock);
> +	edev->desc = desc;
> +	edev->dev.parent = dev;
> +	edev->dev.class = devfreq_event_class;
> +	edev->dev.release = devfreq_event_release_edev;
> +
> +	dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
> +	ret = device_register(&edev->dev);
> +	if (ret < 0) {
> +		put_device(&edev->dev);
> +		return ERR_PTR(ret);
> +	}
> +	dev_set_drvdata(&edev->dev, edev);
> +
> +	INIT_LIST_HEAD(&edev->node);
> +
> +	mutex_lock(&devfreq_event_list_lock);
> +	list_add(&edev->node, &devfreq_event_list);
> +	mutex_unlock(&devfreq_event_list_lock);
> +
> +	return edev;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
> +
> +/**
> + * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
> + * @dev		: the devfreq-event device
> + *
> + * Note that this function remove the registered devfreq-event device.
> + */
> +int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
> +{
> +	if (!edev)
> +		return -EINVAL;
> +
> +	mutex_lock(&devfreq_event_list_lock);
> +	WARN_ON(edev->enable_count);
> +	list_del(&edev->node);
> +	device_unregister(&edev->dev);
> +	mutex_unlock(&devfreq_event_list_lock);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
> +
> +/*
> + * Device attributes for devfreq-event class.
> + */
> +static ssize_t name_show(struct device *dev, struct device_attribute *attr,
> +			 char *buf)
> +{
> +	struct devfreq_event_dev *edev = to_devfreq_event(dev);
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	return sprintf(buf, "%s\n", edev->desc->name);
> +}
> +static DEVICE_ATTR_RO(name);
> +
> +static ssize_t enable_count_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
> +{
> +	struct devfreq_event_dev *edev = to_devfreq_event(dev);
> +
> +	if (!edev || !edev->desc)
> +		return -EINVAL;
> +
> +	return sprintf(buf, "%d\n", edev->enable_count);
> +}
> +static DEVICE_ATTR_RO(enable_count);
> +
> +static struct attribute *devfreq_event_attrs[] = {
> +	&dev_attr_name.attr,
> +	&dev_attr_enable_count.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(devfreq_event);
> +
> +static int __init devfreq_event_init(void)
> +{
> +	devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
> +	if (IS_ERR(devfreq_event_class)) {
> +		pr_err("%s: couldn't create class\n", __FILE__);
> +		return PTR_ERR(devfreq_event_class);
> +	}
> +
> +	devfreq_event_class->dev_groups = devfreq_event_groups;
> +
> +	return 0;
> +}
> +subsys_initcall(devfreq_event_init);
> +
> +static void __exit devfreq_event_exit(void)
> +{
> +	class_destroy(devfreq_event_class);
> +}
> +module_exit(devfreq_event_exit);
> +
> +MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
> +MODULE_DESCRIPTION("DEVFREQ-Event class support");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
> new file mode 100644
> index 0000000..1ced42c
> --- /dev/null
> +++ b/drivers/devfreq/event/Kconfig
> @@ -0,0 +1,16 @@
> +menuconfig PM_DEVFREQ_EVENT
> +	bool "DEVFREQ-Event device Support"
> +	help
> +	  The devfreq-event device provide the raw data and events which
> +	  indicate the current state of devfreq-event device. The provided
> +	  data from devfreq-event device is used to monitor the state of
> +	  device and determine the suitable size of resource to reduce the
> +	  wasted resource.
> +
> +	  The devfreq-event device can support the various type of events
> +	  (e.g., raw data, utilization, latency, bandwidth). The events
> +	  may be used by devfreq governor and other subsystem.
> +
> +if PM_DEVFREQ_EVENT
> +
> +endif # PM_DEVFREQ_EVENT
> diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
> new file mode 100644
> index 0000000..dc56005
> --- /dev/null
> +++ b/drivers/devfreq/event/Makefile
> @@ -0,0 +1 @@
> +# Exynos DEVFREQ Event Drivers
> diff --git a/include/linux/devfreq-event.h b/include/linux/devfreq-event.h
> new file mode 100644
> index 0000000..b7363f5
> --- /dev/null
> +++ b/include/linux/devfreq-event.h
> @@ -0,0 +1,170 @@
> +/*
> + * devfreq-event: a framework to provide raw data and events of devfreq devices
> + *
> + * Copyright (C) 2014 Samsung Electronics
> + * Author: Chanwoo Choi <cw00.choi@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __LINUX_DEVFREQ_EVENT_H__
> +#define __LINUX_DEVFREQ_EVENT_H__
> +
> +#include <linux/device.h>
> +
> +/**
> + * struct devfreq_event_dev - the devfreq-event device
> + *
> + * @node	: Contain the devfreq-event device that have been registered.
> + * @dev		: the device registered by devfreq-event class. dev.parent is
> + *		  the device using devfreq-event.
> + * @lock	: a mutex to protect accessing devfreq-event.
> + * @enable_count: the number of enable function have been called.
> + * @desc	: the description for devfreq-event device.
> + *
> + * This structure contains devfreq-event device information.
> + */
> +struct devfreq_event_dev {
> +	struct list_head node;
> +
> +	struct device dev;
> +	struct mutex lock;
> +	u32 enable_count;
> +
> +	const struct devfreq_event_desc *desc;
> +};
> +
> +/**
> + * struct devfreq_event_data - the devfreq-event data
> + *
> + * @event	: the load of devfreq-event device for polling period
> + * @total_event	: the total load of devfreq-event device for polling period
> + *
> + * This structure contains the data of devfreq-event device for polling period.
> + */
> +struct devfreq_event_data {
> +	unsigned long event;
> +	unsigned long total_event;
> +};
> +
> +/**
> + * struct devfreq_event_ops - the operations of devfreq-event device
> + *
> + * @enable	: Enable the devfreq-event device.
> + * @disable	: Disable the devfreq-event device.
> + * @reset	: Reset all setting of the devfreq-event device.
> + * @set_event	: Set the specific event type for the devfreq-event device.
> + * @get_event	: Get the result of the devfreq-event devie with specific
> + *		  event type.
> + *
> + * This structure contains devfreq-event device operations which can be
> + * implemented by devfreq-event device drivers.
> + */
> +struct devfreq_event_ops {
> +	/* Optional functions */
> +	int (*enable)(struct devfreq_event_dev *edev);
> +	int (*disable)(struct devfreq_event_dev *edev);
> +	int (*reset)(struct devfreq_event_dev *edev);
> +
> +	/* Mandatory functions */
> +	int (*set_event)(struct devfreq_event_dev *edev);
> +	int (*get_event)(struct devfreq_event_dev *edev,
> +			 struct devfreq_event_data *edata);
> +};
> +
> +/**
> + * struct devfreq_event_desc - the descriptor of devfreq-event device
> + *
> + * @name	: the name of devfreq-event device.
> + * @driver_data	: the private data for devfreq-event driver.
> + * @ops		: the operation to control devfreq-event device.
> + *
> + * Each devfreq-event device is described with a this structure.
> + * This structure contains the various data for devfreq-event device.
> + */
> +struct devfreq_event_desc {
> +	const char *name;
> +	void *driver_data;
> +
> +	struct devfreq_event_ops *ops;
> +};
> +
> +#if defined(CONFIG_PM_DEVFREQ_EVENT)
> +extern int devfreq_event_enable_edev(struct devfreq_event_dev *edev);
> +extern int devfreq_event_disable_edev(struct devfreq_event_dev *edev);
> +extern bool devfreq_event_is_enabled(struct devfreq_event_dev *edev);
> +extern int devfreq_event_set_event(struct devfreq_event_dev *edev);
> +extern int devfreq_event_get_event(struct devfreq_event_dev *edev,
> +				struct devfreq_event_data *edata);
> +extern int devfreq_event_reset_event(struct devfreq_event_dev *edev);
> +extern void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev);
> +extern struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
> +				struct device *dev, int index);
> +extern int devfreq_event_get_edev_count(struct device *dev);
> +extern struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
> +				struct devfreq_event_desc *desc);
> +extern int devfreq_event_remove_edev(struct devfreq_event_dev *edev);
> +
> +#else
> +static inline int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
> +{
> +	return false;
> +}
> +
> +static inline int devfreq_event_set_event(struct devfreq_event_dev *edev)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline int devfreq_event_get_event(struct devfreq_event_dev *edev,
> +					struct devfreq_event_data *edata)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline int devfreq_event_reset_event(struct devfreq_event_dev *edev)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
> +					struct device *dev, int index)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline int devfreq_event_get_edev_count(struct device *dev)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
> +					struct devfreq_event_desc *desc)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
> +{
> +	return -EINVAL;
> +}
> +#endif /* CONFIG_PM_DEVFREQ_EVENT */
> +
> +#endif /* __LINUX_DEVFREQ_EVENT_H__ */
> 


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor
  2015-01-12 12:34 [PATCHv8 0/9] devfreq: Add devfreq-event class to provide raw data for devfreq device Chanwoo Choi
@ 2015-01-12 12:34 ` Chanwoo Choi
  2015-01-19 10:12   ` Chanwoo Choi
  0 siblings, 1 reply; 5+ messages in thread
From: Chanwoo Choi @ 2015-01-12 12:34 UTC (permalink / raw)
  To: myungjoo.ham, kgene
  Cc: kyungmin.park, rafael.j.wysocki, mark.rutland, a.kesavan,
	tomasz.figa, k.kozlowski, b.zolnierkie, robh+dt, cw00.choi,
	inki.dae, linux-pm, linux-kernel, linux-arm-kernel,
	linux-samsung-soc

This patch add new devfreq_event class for devfreq_event device which provide
raw data (e.g., memory bus utilization/GPU utilization). This raw data from
devfreq_event data would be used for the governor of devfreq subsystem.
- devfreq_event device : Provide raw data for governor of existing devfreq device
- devfreq device       : Monitor device state and change frequency/voltage of device
                         using the raw data from devfreq_event device

The devfreq subsystem support generic DVFS(Dynamic Voltage/Frequency Scaling)
for Non-CPU Devices. The devfreq device would dertermine current device state
using various governor (e.g., ondemand, performance, powersave). After completed
determination of system state, devfreq device would change the frequency/voltage
of devfreq device according to the result of governor.

But, devfreq governor must need basic data which indicates current device state.
Existing devfreq subsystem only consider devfreq device which check current system
state and determine proper system state using basic data. There is no subsystem
for device providing basic data to devfreq device.

The devfreq subsystem must need devfreq_event device(data-provider device) for
existing devfreq device. So, this patch add new devfreq_event class for
devfreq_event device which read various basic data(e.g, memory bus utilization,
GPU utilization) and provide measured data to existing devfreq device through
standard APIs of devfreq_event class.

The following description explains the feature of two kind of devfreq class:
- devfreq class (existing)
 : devfreq consumer device use raw data from devfreq_event device for
   determining proper current system state and change voltage/frequency
   dynamically using various governors.

- devfreq_event class (new)
 : Provide measured raw data to devfreq device for governor

Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/devfreq/Kconfig         |   2 +
 drivers/devfreq/Makefile        |   6 +-
 drivers/devfreq/devfreq-event.c | 448 ++++++++++++++++++++++++++++++++++++++++
 drivers/devfreq/event/Kconfig   |  16 ++
 drivers/devfreq/event/Makefile  |   1 +
 include/linux/devfreq-event.h   | 170 +++++++++++++++
 6 files changed, 642 insertions(+), 1 deletion(-)
 create mode 100644 drivers/devfreq/devfreq-event.c
 create mode 100644 drivers/devfreq/event/Kconfig
 create mode 100644 drivers/devfreq/event/Makefile
 create mode 100644 include/linux/devfreq-event.h

diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index faf4e70..21f8f17 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -87,4 +87,6 @@ config ARM_EXYNOS5_BUS_DEVFREQ
 	  It reads PPMU counters of memory controllers and adjusts the
 	  operating frequencies and voltages with OPP support.
 
+source "drivers/devfreq/event/Kconfig"
+
 endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 16138c9..c449336 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -1,4 +1,5 @@
-obj-$(CONFIG_PM_DEVFREQ)	+= devfreq.o
+obj-$(CONFIG_PM_DEVFREQ)		+= devfreq.o
+obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= devfreq-event.o
 obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)	+= governor_simpleondemand.o
 obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
 obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
@@ -7,3 +8,6 @@ obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
 # DEVFREQ Drivers
 obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/
 obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ)	+= exynos/
+
+# DEVFREQ Event Drivers
+obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= event/
diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
new file mode 100644
index 0000000..9ba5ba4
--- /dev/null
+++ b/drivers/devfreq/devfreq-event.c
@@ -0,0 +1,448 @@
+/*
+ * devfreq-event: a framework to provide raw data and events of devfreq devices
+ *
+ * Copyright (C) 2014 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This driver is based on drivers/devfreq/devfreq.c.
+ */
+
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/of.h>
+
+static struct class *devfreq_event_class;
+
+/* The list of all devfreq event list */
+static LIST_HEAD(devfreq_event_list);
+static DEFINE_MUTEX(devfreq_event_list_lock);
+
+#define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
+
+/**
+ * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
+ *				 the enable_count of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function increase the enable_count and enable the
+ * devfreq-event device. The devfreq-event device should be enabled before
+ * using it by devfreq device.
+ */
+int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	mutex_lock(&edev->lock);
+	if (edev->desc->ops && edev->desc->ops->enable) {
+		ret = edev->desc->ops->enable(edev);
+		if (ret < 0)
+			goto err;
+	}
+	edev->enable_count++;
+err:
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
+
+/**
+ * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
+ *				  the enable_count of the devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function decrease the enable_count and disable the
+ * devfreq-event device. After the devfreq-event device is disabled,
+ * devfreq device can't use the devfreq-event device for get/set/reset
+ * operations.
+ */
+int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	mutex_lock(&edev->lock);
+	if (edev->enable_count > 0) {
+		edev->enable_count--;
+	} else {
+		dev_warn(&edev->dev, "unbalanced enable_count\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (edev->desc->ops && edev->desc->ops->disable) {
+		ret = edev->desc->ops->disable(edev);
+		if (ret < 0) {
+			edev->enable_count++;
+			goto err;
+		}
+	}
+err:
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
+
+/**
+ * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
+ *				not.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function check whether devfreq-event dev is enabled or not.
+ * If return true, the devfreq-event dev is enabeld. If return false, the
+ * devfreq-event dev is disabled.
+ */
+bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
+{
+	bool enabled = false;
+
+	if (!edev || !edev->desc)
+		return enabled;
+
+	mutex_lock(&edev->lock);
+
+	if (edev->enable_count > 0)
+		enabled = true;
+
+	mutex_unlock(&edev->lock);
+
+	return enabled;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
+
+/**
+ * devfreq_event_set_event() - Set event to devfreq-event dev to start.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function set the event to the devfreq-event device to start
+ * for getting the event data which could be various event type.
+ */
+int devfreq_event_set_event(struct devfreq_event_dev *edev)
+{
+	int ret;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!edev->desc->ops || !edev->desc->ops->set_event)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EPERM;
+
+	mutex_lock(&edev->lock);
+	ret = edev->desc->ops->set_event(edev);
+	mutex_unlock(&edev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_set_event);
+
+/**
+ * devfreq_event_get_event() - Get event and total_event from devfreq-event dev.
+ * @edev	: the devfreq-event device
+ * @edata	: the calculated data of devfreq-event device
+ *
+ * Note that this function get the calculated event data from devfreq-event dev
+ * after stoping the progress of whole sequence of devfreq-event dev.
+ */
+int devfreq_event_get_event(struct devfreq_event_dev *edev,
+			    struct devfreq_event_data *edata)
+{
+	int ret;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!edev->desc->ops || !edev->desc->ops->get_event)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EINVAL;
+
+	edata->event = edata->total_event = 0;
+
+	mutex_lock(&edev->lock);
+	ret = edev->desc->ops->get_event(edev, edata);
+	mutex_unlock(&edev->lock);
+
+	if ((edata->total_event <= 0)
+		|| (edata->event > edata->total_event)) {
+		edata->event = edata->total_event = 0;
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_event);
+
+/**
+ * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function stop all operations of devfreq-event dev and reset
+ * the current event data to make the devfreq-event device into initial state.
+ */
+int devfreq_event_reset_event(struct devfreq_event_dev *edev)
+{
+	int ret = 0;
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	if (!devfreq_event_is_enabled(edev))
+		return -EPERM;
+
+	mutex_lock(&edev->lock);
+	if (edev->desc->ops && edev->desc->ops->reset)
+		ret = edev->desc->ops->reset(edev);
+	mutex_unlock(&edev->lock);
+
+	if (ret < 0)
+		return -EINVAL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
+
+/**
+ * devfreq_event_get_drvdata() - Return driver-data of devfreq-event dev.
+ * @edev	: the devfreq-event device
+ *
+ * Note that this function return the driver-data of devfreq-event device.
+ */
+void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
+{
+	return edev->desc->driver_data;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_drvdata);
+
+/**
+ * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
+ *					 devicetree.
+ * @dev		: the pointer to the given device
+ * @index	: the index into list of devfreq-event device
+ *
+ * Note that this function return the pointer of devfreq-event device.
+ */
+struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
+						      int index)
+{
+	struct device_node *node;
+	struct devfreq_event_dev *edev;
+
+	if (!dev->of_node) {
+		dev_err(dev, "device does not have a device node entry\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	node = of_parse_phandle(dev->of_node, "devfreq-events", index);
+	if (!node) {
+		dev_err(dev, "failed to get phandle in %s node\n",
+			dev->of_node->full_name);
+		return ERR_PTR(-ENODEV);
+	}
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_for_each_entry(edev, &devfreq_event_list, node) {
+		if (!strcmp(edev->desc->name, node->name))
+			goto out;
+	}
+	edev = NULL;
+out:
+	mutex_unlock(&devfreq_event_list_lock);
+
+	if (!edev) {
+		dev_err(dev, "unable to get devfreq-event device : %s\n",
+			node->name);
+		of_node_put(node);
+		return ERR_PTR(-ENODEV);
+	}
+
+	of_node_put(node);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
+
+/**
+ * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
+ * @dev		: the pointer to the given device
+ *
+ * Note that this function return the count of devfreq-event devices.
+ */
+int devfreq_event_get_edev_count(struct device *dev)
+{
+	int count;
+
+	if (!dev->of_node) {
+		dev_err(dev, "device does not have a device node entry\n");
+		return -EINVAL;
+	}
+
+	count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
+						sizeof(u32));
+	if (count < 0 ) {
+		dev_err(dev,
+			"failed to get the count of devfreq-event in %s node\n",
+			dev->of_node->full_name);
+		return count;
+	}
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
+
+static void devfreq_event_release_edev(struct device *dev)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	kfree(edev);
+}
+
+/**
+ * devfreq_event_add_edev() - Add new devfreq-event device.
+ * @dev		: the device owning the devfreq-event device being created
+ * @desc	: the devfreq-event device's decriptor which include essential
+ *		  data for devfreq-event device.
+ *
+ * Note that this function add new devfreq-event device to devfreq-event class
+ * list and register the device of the devfreq-event device.
+ */
+struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+						struct devfreq_event_desc *desc)
+{
+	struct devfreq_event_dev *edev;
+	static atomic_t event_no = ATOMIC_INIT(0);
+	int ret;
+
+	if (!dev || !desc)
+		return ERR_PTR(-EINVAL);
+
+	if (!desc->name || !desc->ops)
+		return ERR_PTR(-EINVAL);
+
+	if (!desc->ops->set_event || !desc->ops->get_event)
+		return ERR_PTR(-EINVAL);
+
+	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
+	if (!edev)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&edev->lock);
+	edev->desc = desc;
+	edev->dev.parent = dev;
+	edev->dev.class = devfreq_event_class;
+	edev->dev.release = devfreq_event_release_edev;
+
+	dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
+	ret = device_register(&edev->dev);
+	if (ret < 0) {
+		put_device(&edev->dev);
+		return ERR_PTR(ret);
+	}
+	dev_set_drvdata(&edev->dev, edev);
+
+	INIT_LIST_HEAD(&edev->node);
+
+	mutex_lock(&devfreq_event_list_lock);
+	list_add(&edev->node, &devfreq_event_list);
+	mutex_unlock(&devfreq_event_list_lock);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
+
+/**
+ * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
+ * @dev		: the devfreq-event device
+ *
+ * Note that this function remove the registered devfreq-event device.
+ */
+int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
+{
+	if (!edev)
+		return -EINVAL;
+
+	mutex_lock(&devfreq_event_list_lock);
+	WARN_ON(edev->enable_count);
+	list_del(&edev->node);
+	device_unregister(&edev->dev);
+	mutex_unlock(&devfreq_event_list_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
+
+/*
+ * Device attributes for devfreq-event class.
+ */
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", edev->desc->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t enable_count_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct devfreq_event_dev *edev = to_devfreq_event(dev);
+
+	if (!edev || !edev->desc)
+		return -EINVAL;
+
+	return sprintf(buf, "%d\n", edev->enable_count);
+}
+static DEVICE_ATTR_RO(enable_count);
+
+static struct attribute *devfreq_event_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_enable_count.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(devfreq_event);
+
+static int __init devfreq_event_init(void)
+{
+	devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
+	if (IS_ERR(devfreq_event_class)) {
+		pr_err("%s: couldn't create class\n", __FILE__);
+		return PTR_ERR(devfreq_event_class);
+	}
+
+	devfreq_event_class->dev_groups = devfreq_event_groups;
+
+	return 0;
+}
+subsys_initcall(devfreq_event_init);
+
+static void __exit devfreq_event_exit(void)
+{
+	class_destroy(devfreq_event_class);
+}
+module_exit(devfreq_event_exit);
+
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_DESCRIPTION("DEVFREQ-Event class support");
+MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
new file mode 100644
index 0000000..1ced42c
--- /dev/null
+++ b/drivers/devfreq/event/Kconfig
@@ -0,0 +1,16 @@
+menuconfig PM_DEVFREQ_EVENT
+	bool "DEVFREQ-Event device Support"
+	help
+	  The devfreq-event device provide the raw data and events which
+	  indicate the current state of devfreq-event device. The provided
+	  data from devfreq-event device is used to monitor the state of
+	  device and determine the suitable size of resource to reduce the
+	  wasted resource.
+
+	  The devfreq-event device can support the various type of events
+	  (e.g., raw data, utilization, latency, bandwidth). The events
+	  may be used by devfreq governor and other subsystem.
+
+if PM_DEVFREQ_EVENT
+
+endif # PM_DEVFREQ_EVENT
diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
new file mode 100644
index 0000000..dc56005
--- /dev/null
+++ b/drivers/devfreq/event/Makefile
@@ -0,0 +1 @@
+# Exynos DEVFREQ Event Drivers
diff --git a/include/linux/devfreq-event.h b/include/linux/devfreq-event.h
new file mode 100644
index 0000000..b7363f5
--- /dev/null
+++ b/include/linux/devfreq-event.h
@@ -0,0 +1,170 @@
+/*
+ * devfreq-event: a framework to provide raw data and events of devfreq devices
+ *
+ * Copyright (C) 2014 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __LINUX_DEVFREQ_EVENT_H__
+#define __LINUX_DEVFREQ_EVENT_H__
+
+#include <linux/device.h>
+
+/**
+ * struct devfreq_event_dev - the devfreq-event device
+ *
+ * @node	: Contain the devfreq-event device that have been registered.
+ * @dev		: the device registered by devfreq-event class. dev.parent is
+ *		  the device using devfreq-event.
+ * @lock	: a mutex to protect accessing devfreq-event.
+ * @enable_count: the number of enable function have been called.
+ * @desc	: the description for devfreq-event device.
+ *
+ * This structure contains devfreq-event device information.
+ */
+struct devfreq_event_dev {
+	struct list_head node;
+
+	struct device dev;
+	struct mutex lock;
+	u32 enable_count;
+
+	const struct devfreq_event_desc *desc;
+};
+
+/**
+ * struct devfreq_event_data - the devfreq-event data
+ *
+ * @event	: the load of devfreq-event device for polling period
+ * @total_event	: the total load of devfreq-event device for polling period
+ *
+ * This structure contains the data of devfreq-event device for polling period.
+ */
+struct devfreq_event_data {
+	unsigned long event;
+	unsigned long total_event;
+};
+
+/**
+ * struct devfreq_event_ops - the operations of devfreq-event device
+ *
+ * @enable	: Enable the devfreq-event device.
+ * @disable	: Disable the devfreq-event device.
+ * @reset	: Reset all setting of the devfreq-event device.
+ * @set_event	: Set the specific event type for the devfreq-event device.
+ * @get_event	: Get the result of the devfreq-event devie with specific
+ *		  event type.
+ *
+ * This structure contains devfreq-event device operations which can be
+ * implemented by devfreq-event device drivers.
+ */
+struct devfreq_event_ops {
+	/* Optional functions */
+	int (*enable)(struct devfreq_event_dev *edev);
+	int (*disable)(struct devfreq_event_dev *edev);
+	int (*reset)(struct devfreq_event_dev *edev);
+
+	/* Mandatory functions */
+	int (*set_event)(struct devfreq_event_dev *edev);
+	int (*get_event)(struct devfreq_event_dev *edev,
+			 struct devfreq_event_data *edata);
+};
+
+/**
+ * struct devfreq_event_desc - the descriptor of devfreq-event device
+ *
+ * @name	: the name of devfreq-event device.
+ * @driver_data	: the private data for devfreq-event driver.
+ * @ops		: the operation to control devfreq-event device.
+ *
+ * Each devfreq-event device is described with a this structure.
+ * This structure contains the various data for devfreq-event device.
+ */
+struct devfreq_event_desc {
+	const char *name;
+	void *driver_data;
+
+	struct devfreq_event_ops *ops;
+};
+
+#if defined(CONFIG_PM_DEVFREQ_EVENT)
+extern int devfreq_event_enable_edev(struct devfreq_event_dev *edev);
+extern int devfreq_event_disable_edev(struct devfreq_event_dev *edev);
+extern bool devfreq_event_is_enabled(struct devfreq_event_dev *edev);
+extern int devfreq_event_set_event(struct devfreq_event_dev *edev);
+extern int devfreq_event_get_event(struct devfreq_event_dev *edev,
+				struct devfreq_event_data *edata);
+extern int devfreq_event_reset_event(struct devfreq_event_dev *edev);
+extern void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev);
+extern struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
+				struct device *dev, int index);
+extern int devfreq_event_get_edev_count(struct device *dev);
+extern struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+				struct devfreq_event_desc *desc);
+extern int devfreq_event_remove_edev(struct devfreq_event_dev *edev);
+
+#else
+static inline int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
+{
+	return false;
+}
+
+static inline int devfreq_event_set_event(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_event_get_event(struct devfreq_event_dev *edev,
+					struct devfreq_event_data *edata)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_event_reset_event(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+
+static inline void *devfreq_event_get_drvdata(struct devfreq_event_dev *edev)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(
+					struct device *dev, int index)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline int devfreq_event_get_edev_count(struct device *dev)
+{
+	return -EINVAL;
+}
+
+static inline struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
+					struct devfreq_event_desc *desc)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_PM_DEVFREQ_EVENT */
+
+#endif /* __LINUX_DEVFREQ_EVENT_H__ */
-- 
1.8.5.5


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2015-01-20  7:25 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-01-20  4:34 [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor MyungJoo Ham
2015-01-20  5:29 ` Chanwoo Choi
  -- strict thread matches above, loose matches on Subject: below --
2015-01-20  6:59 MyungJoo Ham
2015-01-20  7:25 ` Chanwoo Choi
2015-01-12 12:34 [PATCHv8 0/9] devfreq: Add devfreq-event class to provide raw data for devfreq device Chanwoo Choi
2015-01-12 12:34 ` [PATCHv8 1/9] devfreq: event: Add new devfreq_event class to provide basic data for devfreq governor Chanwoo Choi
2015-01-19 10:12   ` Chanwoo Choi

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).