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

[Suzuki K Poulose]

On 11/09/2018 05:59 PM, Mathieu Poirier wrote:
> On Thu, 8 Nov 2018 at 10:13, Suzuki K Poulose <suzuki.poulose@xxxxxxx> 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@xxxxxxxxxx>
> > > ---
> > >    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@xxxxxxx>


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);