linux-kernel - Re: [PATCH v3 2/4] drivers: devfreq: events: extend events by type of counted data

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Date:   Thu, 2 May 2019 11:07:43 +0200
From:   Lukasz Luba <l.luba@...tner.samsung.com>
To:     Chanwoo Choi <cw00.choi@...sung.com>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     b.zolnierkie@...sung.com, krzk@...nel.org, robh+dt@...nel.org,
        mark.rutland@....com, kyungmin.park@...sung.com,
        m.szyprowski@...sung.com, s.nawrocki@...sung.com,
        myungjoo.ham@...sung.com, kgene@...nel.org,
        willy.mh.wolff.ml@...il.com
Subject: Re: [PATCH v3 2/4] drivers: devfreq: events: extend events by type
 of counted data



On 5/2/19 3:25 AM, Chanwoo Choi wrote:
> Hi Lukasz,
> 
> On 19. 5. 1. 오전 6:19, Lukasz Luba wrote:
>> Hi Chanwoo,
>>
>> On 4/30/19 9:34 AM, Chanwoo Choi wrote:
>>> Hi Lukasz,
>>>
>>> On 19. 4. 19. 오후 10:48, Lukasz Luba wrote:
>>>> This patch adds posibility to choose what type of data should be counted
>>>> by the PPMU counter. Now the type comes from DT where the event has been
>>>> defined. When there is no 'event-data-type' the default value is used,
>>>> which is 'read data in bytes'.
>>>> It is needed when you want to know not only read+write data bytes but
>>>> i.e. only write data in byte, or number of read requests, etc.
>>>>
>>>> Signed-off-by: Lukasz Luba <l.luba@...tner.samsung.com>
>>>> ---
>>>>    drivers/devfreq/event/exynos-ppmu.c | 61 +++++++++++++++++++++++++------------
>>>>    include/linux/devfreq-event.h       |  6 ++++
>>>>    2 files changed, 48 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/event/exynos-ppmu.c b/drivers/devfreq/event/exynos-ppmu.c
>>>> index c61de0b..073bf2c 100644
>>>> --- a/drivers/devfreq/event/exynos-ppmu.c
>>>> +++ b/drivers/devfreq/event/exynos-ppmu.c
>>>> @@ -154,9 +154,9 @@ static int exynos_ppmu_set_event(struct devfreq_event_dev *edev)
>>>>    	if (ret < 0)
>>>>    		return ret;
>>>>    
>>>> -	/* Set the event of Read/Write data count  */
>>>> +	/* Set the event of proper data type monitoring */
>>>>    	ret = regmap_write(info->regmap, PPMU_BEVTxSEL(id),
>>>> -				PPMU_RO_DATA_CNT | PPMU_WO_DATA_CNT);
>>>> +			   edev->desc->data_type);
>>>>    	if (ret < 0)
>>>>    		return ret;
>>>>    
>>>> @@ -368,23 +368,11 @@ static int exynos_ppmu_v2_set_event(struct devfreq_event_dev *edev)
>>>>    	if (ret < 0)
>>>>    		return ret;
>>>>    
>>>> -	/* Set the event of Read/Write data count  */
>>>> -	switch (id) {
>>>> -	case PPMU_PMNCNT0:
>>>> -	case PPMU_PMNCNT1:
>>>> -	case PPMU_PMNCNT2:
>>>> -		ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id),
>>>> -				PPMU_V2_RO_DATA_CNT | PPMU_V2_WO_DATA_CNT);
>>>> -		if (ret < 0)
>>>> -			return ret;
>>>> -		break;
>>>> -	case PPMU_PMNCNT3:
>>>> -		ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id),
>>>> -				PPMU_V2_EVT3_RW_DATA_CNT);
>>>> -		if (ret < 0)
>>>> -			return ret;
>>>> -		break;
>>>> -	}
>>>> +	/* Set the event of proper data type monitoring */
>>>> +	ret = regmap_write(info->regmap, PPMU_V2_CH_EVx_TYPE(id),
>>>> +			   edev->desc->data_type);
>>>> +	if (ret < 0)
>>>> +		return ret;
>>>>    
>>>>    	/* Reset cycle counter/performance counter and enable PPMU */
>>>>    	ret = regmap_read(info->regmap, PPMU_V2_PMNC, &pmnc);
>>>> @@ -508,6 +496,7 @@ static int of_get_devfreq_events(struct device_node *np,
>>>>    	struct device *dev = info->dev;
>>>>    	struct device_node *events_np, *node;
>>>>    	int i, j, count;
>>>> +	int ret;
>>>>    
>>>>    	events_np = of_get_child_by_name(np, "events");
>>>>    	if (!events_np) {
>>>> @@ -544,6 +533,40 @@ static int of_get_devfreq_events(struct device_node *np,
>>>>    		desc[j].driver_data = info;
>>>>    
>>>>    		of_property_read_string(node, "event-name", &desc[j].name);
>>>> +		ret = of_property_read_u32(node, "event-data-type",
>>>> +					   &desc[j].data_type);
>>>> +		if (ret) {
>>>> +			/* Set the event of proper data type counting.
>>>> +			 * Check if the data type has been defined in DT,
>>>> +			 * use default if not.
>>>> +			 */
>>>> +			if (of_device_is_compatible(np,
>>>> +					"samsung,exynos-ppmu-v2")) {
>>>
>>> It is not proper to compare the compatible string again
>>> in the device driver. Instead, you can define the ppmu device type
>>> as following and then use 'struct of_device_id' in order to
>>> identify the device type.
>> I have been thinking about modifying the code in similar fashion as you
>> did. Good to see similar approach. I'll take your changes with a small
>> additional code, which sets the 'info->ppmu_type' before the for
>> loop, as an additional patch. Would it be OK if I add you as an author
>> and add Sign-off-by: Chanwoo Choi <cw00.choi@...sung.com>?
> 
> If you agree, just add the my signed-off-by on second line.
OK

Regards,
Lukasz