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[PATCH V3 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE

Anshuman Khandual posted 4 patches 2 years, 6 months ago
There is a newer version of this series
[PATCH V3 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE
Posted by Anshuman Khandual 2 years, 6 months ago 
TRBE coresight devices do not need regular connections information, as the
paths get built between all percpu source and their respective percpu sink
devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support
for dedicated percpu sinks")' which added support for percpu sink devices.

coresight_register() expect device connections via the platform_data. TRBE
devices do not have any graph connections and thus is empty. With upcoming
ACPI support for TRBE, we do not get a real acpi_device and thus
coresight_get_platform_dat() will end up in failures. Hence this allocates
a zeroed coresight_platform_data structure and assigns that back into the
device.

Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 7720619909d6..e1d9d06e7725 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1494,9 +1494,9 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
 	if (!drvdata)
 		return -ENOMEM;
 
-	pdata = coresight_get_platform_data(dev);
-	if (IS_ERR(pdata))
-		return PTR_ERR(pdata);
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
 
 	dev_set_drvdata(dev, drvdata);
 	dev->platform_data = pdata;
-- 
2.25.1
Re: [PATCH V3 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE
Posted by Suzuki K Poulose 2 years, 6 months ago 
On 03/08/2023 06:56, Anshuman Khandual wrote:
> TRBE coresight devices do not need regular connections information, as the
> paths get built between all percpu source and their respective percpu sink
> devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support
> for dedicated percpu sinks")' which added support for percpu sink devices.
> 
> coresight_register() expect device connections via the platform_data. TRBE
> devices do not have any graph connections and thus is empty. With upcoming
> ACPI support for TRBE, we do not get a real acpi_device and thus
> coresight_get_platform_dat() will end up in failures. Hence this allocates
> a zeroed coresight_platform_data structure and assigns that back into the
> device.
> 
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: coresight@lists.linaro.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>   drivers/hwtracing/coresight/coresight-trbe.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> index 7720619909d6..e1d9d06e7725 100644
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -1494,9 +1494,9 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
>   	if (!drvdata)
>   		return -ENOMEM;
>   
> -	pdata = coresight_get_platform_data(dev);
> -	if (IS_ERR(pdata))
> -		return PTR_ERR(pdata);
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;

Please could you add a comment in here, on why we use a dummy platform
data ? It is good to have documented it in the code too.

Suzuki


>   
>   	dev_set_drvdata(dev, drvdata);
>   	dev->platform_data = pdata;
Re: [PATCH V3 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE
Posted by Anshuman Khandual 2 years, 6 months ago 

On 8/3/23 19:25, Suzuki K Poulose wrote:
> On 03/08/2023 06:56, Anshuman Khandual wrote:
>> TRBE coresight devices do not need regular connections information, as the
>> paths get built between all percpu source and their respective percpu sink
>> devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support
>> for dedicated percpu sinks")' which added support for percpu sink devices.
>>
>> coresight_register() expect device connections via the platform_data. TRBE
>> devices do not have any graph connections and thus is empty. With upcoming
>> ACPI support for TRBE, we do not get a real acpi_device and thus
>> coresight_get_platform_dat() will end up in failures. Hence this allocates
>> a zeroed coresight_platform_data structure and assigns that back into the
>> device.
>>
>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Cc: Mike Leach <mike.leach@linaro.org>
>> Cc: Leo Yan <leo.yan@linaro.org>
>> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
>> Cc: coresight@lists.linaro.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-trbe.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
>> index 7720619909d6..e1d9d06e7725 100644
>> --- a/drivers/hwtracing/coresight/coresight-trbe.c
>> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
>> @@ -1494,9 +1494,9 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
>>       if (!drvdata)
>>           return -ENOMEM;
>>   -    pdata = coresight_get_platform_data(dev);
>> -    if (IS_ERR(pdata))
>> -        return PTR_ERR(pdata);
>> +    pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
>> +    if (!pdata)
>> +        return -ENOMEM;
> 
> Please could you add a comment in here, on why we use a dummy platform
> data ? It is good to have documented it in the code too.

Sure, will add the following in-code documentation.

+       /*
+        * TRBE coresight devices do not need regular connections
+        * information, as the paths get built between all percpu
+        * source and their respective percpu sink devices. Though
+        * coresight_register() expect device connections via the
+        * platform_data, which TRBE devices do not have. As they
+        * are not real ACPI devices, coresight_get_platform_dat()
+        * ends up failing. Instead let's allocate a dummy zeroed
+        * coresight_platform_data structure and assign that back
+        * into the device for that purpose.
+        */
Re: [PATCH V3 3/4] coresight: trbe: Add a representative coresight_platform_data for TRBE
Posted by Suzuki K Poulose 2 years, 6 months ago 
On 04/08/2023 10:18, Anshuman Khandual wrote:
> 
> 
> On 8/3/23 19:25, Suzuki K Poulose wrote:
>> On 03/08/2023 06:56, Anshuman Khandual wrote:
>>> TRBE coresight devices do not need regular connections information, as the
>>> paths get built between all percpu source and their respective percpu sink
>>> devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support
>>> for dedicated percpu sinks")' which added support for percpu sink devices.
>>>
>>> coresight_register() expect device connections via the platform_data. TRBE
>>> devices do not have any graph connections and thus is empty. With upcoming
>>> ACPI support for TRBE, we do not get a real acpi_device and thus
>>> coresight_get_platform_dat() will end up in failures. Hence this allocates
>>> a zeroed coresight_platform_data structure and assigns that back into the
>>> device.
>>>
>>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> Cc: Mike Leach <mike.leach@linaro.org>
>>> Cc: Leo Yan <leo.yan@linaro.org>
>>> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
>>> Cc: coresight@lists.linaro.org
>>> Cc: linux-arm-kernel@lists.infradead.org
>>> Cc: linux-kernel@vger.kernel.org
>>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>>> ---
>>>    drivers/hwtracing/coresight/coresight-trbe.c | 6 +++---
>>>    1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
>>> index 7720619909d6..e1d9d06e7725 100644
>>> --- a/drivers/hwtracing/coresight/coresight-trbe.c
>>> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
>>> @@ -1494,9 +1494,9 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
>>>        if (!drvdata)
>>>            return -ENOMEM;
>>>    -    pdata = coresight_get_platform_data(dev);
>>> -    if (IS_ERR(pdata))
>>> -        return PTR_ERR(pdata);
>>> +    pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
>>> +    if (!pdata)
>>> +        return -ENOMEM;
>>
>> Please could you add a comment in here, on why we use a dummy platform
>> data ? It is good to have documented it in the code too.
> 
> Sure, will add the following in-code documentation.
> 
> +       /*
> +        * TRBE coresight devices do not need regular connections
> +        * information, as the paths get built between all percpu
> +        * source and their respective percpu sink devices. Though
> +        * coresight_register() expect device connections via the
> +        * platform_data, which TRBE devices do not have. As they
> +        * are not real ACPI devices, coresight_get_platform_dat()

minor nit: s/coresight_get_platform_dat/coresight_get_platform_data/
here and above in the description.

Otherwise, looks good.

Suzuki

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