linux-kernel - Re: [PATCH v3 06/26] coresight: etm4x: Handle access to TRCSSPCICRn

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Date:   Mon, 2 Nov 2020 22:04:16 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     linux-arm-kernel@...ts.infradead.org, mike.leach@...aro.org,
        coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 06/26] coresight: etm4x: Handle access to TRCSSPCICRn

On 11/2/20 9:46 PM, Mathieu Poirier wrote:
> Hi Suzuki,
> 
> On Wed, Oct 28, 2020 at 10:09:25PM +0000, Suzuki K Poulose wrote:
>> TRCSSPCICR<n> is present only if all of the following are true:
>> 	TRCIDR4.NUMSSCC > n.
>> 	TRCIDR4.NUMPC > 0b0000 .
>> 	TRCSSCSR<n>.PC == 0b1
>>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
>> ---
>>   drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 ++++++++-----
>>   1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> index d78a37b6592c..0310eac9dc16 100644
>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>> @@ -175,8 +175,9 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
>>   			       drvdata->base + TRCSSCCRn(i));
>>   		writel_relaxed(config->ss_status[i],
>>   			       drvdata->base + TRCSSCSRn(i));
>> -		writel_relaxed(config->ss_pe_cmp[i],
>> -			       drvdata->base + TRCSSPCICRn(i));
>> +		if (drvdata->nr_pe)
> 
> Aren't you missing to check the value of the PC bit in TRCSSCSRn?
> 
>                  /*
>                   * TRCSSCSRn:PC, bit[3]: Indidate support for single-shot PE
>                   * comparator input.
>                   */
>                  if (drvdata->nr_pe && (config->ss_status[i] & BIT(3)))
> 
> 

You're right. Thank for catching this. I will update the series and drop
the patches 1-5.


> I have picked up patches 1 to 5 and added a "Cc:stable" to paches 2, 4 and 5.
> More comments to come tomorrow.

Thanks !
Suzuki