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SubjectRe: [PATCH v2 3/4] coresight: etm3x: Deal with CLAIM tag before and after accessing HW
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On 11/09/2018 05:59 PM, Mathieu Poirier wrote:
> On Thu, 8 Nov 2018 at 10:13, Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
>>
>> Hi,
>>
>> On 07/11/2018 23:08, Mathieu Poirier wrote:
>>> This patch moves access to the CLAIM tag so that no modification to the HW
>>> happens before and after the CLAIM operation has been carried.
>>>
>>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> ---
>>> drivers/hwtracing/coresight/coresight-etm3x.c | 16 ++++++++--------
>>> 1 file changed, 8 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
>>> index fd5c4cca7db5..4f638d81a66a 100644
>>> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
>>> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
>>> @@ -363,15 +363,16 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
>>>
>>> CS_UNLOCK(drvdata->base);
>>>
>>> + rc = coresight_claim_device_unlocked(drvdata->base);
>>> + if (rc)
>>> + goto done;
>>> +
>>> /* Turn engine on */
>>> etm_clr_pwrdwn(drvdata);
>>> /* Apply power to trace registers */
>>> etm_set_pwrup(drvdata);
>>> /* Make sure all registers are accessible */
>>> etm_os_unlock(drvdata);
>>> - rc = coresight_claim_device_unlocked(drvdata->base);
>>> - if (rc)
>>> - goto done;
>>>
>>> etm_set_prog(drvdata);
>>>
>>> @@ -422,12 +423,11 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
>>> etm_clr_prog(drvdata);
>>>
>>> done:
>>> - if (rc)
>>> - etm_set_pwrdwn(drvdata);
>>> CS_LOCK(drvdata->base);
>>>
>>> - dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
>>> - drvdata->cpu, rc);
>>> + if (!rc)
>>> + dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
>>> + drvdata->cpu, rc);
>>
>> Isn't it good to report the failure case too ? Anyway it is dev_dbg and
>> will be a useful info when we debug issues. Otherwise,
>
> Simply removing the "if (!rc)" will do the trick. Can I do the
> modification and add your tag or you prefer to see another revision?

I am fine with that change folded in, no need to respin it.

>
>>
>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>


Cheers
Suzuki


>>
>>> return rc;
>>> }
>>>
>>> @@ -577,9 +577,9 @@ static void etm_disable_hw(void *info)
>>> for (i = 0; i < drvdata->nr_cntr; i++)
>>> config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
>>>
>>> + etm_set_pwrdwn(drvdata);
>>> coresight_disclaim_device_unlocked(drvdata->base);
>>>
>>> - etm_set_pwrdwn(drvdata);
>>> CS_LOCK(drvdata->base);
>>>
>>> dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);
>>>
>>

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