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SubjectRe: [PATCH v2 3/4] coresight: etm3x: Deal with CLAIM tag before and after accessing HW
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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,

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

> 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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