Re: [PATCH v5 4/7] coresight-tgu: Add TGU decode support

[songchai <quic_songchai@quicinc.com>]

On 5/29/2025 7:32 PM, Jonathan Cameron wrote:
> On Thu, 29 May 2025 16:19:45 +0800
> Songwei Chai <quic_songchai@quicinc.com> wrote:
>
>> Decoding is when all the potential pieces for creating a trigger
>> are brought together for a given step. Example - there may be a
>> counter keeping track of some occurrences and a priority-group that
>> is being used to detect a pattern on the sense inputs. These 2
>> inputs to condition_decode must be programmed, for a given step,
>> to establish the condition for the trigger, or movement to another
>> steps.
>>
>> Signed-off-by: Songwei Chai <quic_songchai@quicinc.com>
>> diff --git a/drivers/hwtracing/coresight/coresight-tgu.c b/drivers/hwtracing/coresight/coresight-tgu.c
>> index 6dbfd4c604b1..8dbe8ab30174 100644
>> --- a/drivers/hwtracing/coresight/coresight-tgu.c
>> +++ b/drivers/hwtracing/coresight/coresight-tgu.c
>> @@ -21,13 +21,35 @@ static int calculate_array_location(struct tgu_drvdata *drvdata,
>> +
>>   static int tgu_enable(struct coresight_device *csdev, enum cs_mode mode,
>>   		      void *data)
>>   {
>> +	int ret = 0;
>  From what can be seen here, looks like ret is always set, so no need to init.
Would this initialization improve the determinism of the code? :-)
>>   	struct tgu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>>   
>>   	spin_lock(&drvdata->spinlock);
>> @@ -150,11 +264,15 @@ static int tgu_enable(struct coresight_device *csdev, enum cs_mode mode,
>>   		spin_unlock(&drvdata->spinlock);
>>   		return -EBUSY;
>>   	}
>> -	tgu_write_all_hw_regs(drvdata);
>> +	ret = tgu_write_all_hw_regs(drvdata);
>> +
>> +	if (ret == -EINVAL)
>> +		goto exit;
>>   	drvdata->enable = true;
>>   
>> +exit:
>>   	spin_unlock(&drvdata->spinlock);
>> -	return 0;
>> +	return ret;
>>   }
>> diff --git a/drivers/hwtracing/coresight/coresight-tgu.h b/drivers/hwtracing/coresight/coresight-tgu.h
>> index f07ead505365..691da393ffa3 100644
>> --- a/drivers/hwtracing/coresight/coresight-tgu.h
>> +++ b/drivers/hwtracing/coresight/coresight-tgu.h
>>   enum operation_index {
>>   	TGU_PRIORITY0,
>>   	TGU_PRIORITY1,
>>   	TGU_PRIORITY2,
>> -	TGU_PRIORITY3
>> +	TGU_PRIORITY3,
> And here is why the previous patch should definitely have had the ,
Thanks for your clarification.
>
>> +	TGU_CONDITION_DECODE
>>   
>>   };
>>