Re: [PATCH] coresight: tmc: Cleanup operation mode handling

[Suzuki K Poulose]

On 16/09/16 18:07, Mathieu Poirier wrote:
> On 14 September 2016 at 07:53, Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
> > The mode of operation of the TMC tracked in drvdata->mode is defined
> > as a local_t type. This is always checked and modified under the
> > drvdata->spinlock and hence we don't need local_t for it and the
> > unnecessary synchronisation instructions that comes with it. This
> > change makes the code a bit more cleaner.
> >
> > Also fixes the order in which we update the drvdata->mode to
> > CS_MODE_DISABLED. i.e, in tmc_disable_etX_sink we change the
> > mode to CS_MODE_DISABLED before invoking tmc_disable_etX_hw()
> > which in turn depends on the mode to decide whether to dump the
> > trace to a buffer.
>
> Thank you for the patch - just a few comments below.


> > @@ -194,17 +192,17 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, u32 mode)
> >                 goto out;
> >         }
> >
> > -       val = local_xchg(&drvdata->mode, mode);
> >         /*
> >          * In Perf mode there can be only one writer per sink.  There
> >          * is also no need to continue if the ETB/ETR is already operated
> >          * from sysFS.
> >          */
> > -       if (val != CS_MODE_DISABLED) {
> > +       if (drvdata->mode != CS_MODE_DISABLED) {
> >                 ret = -EINVAL;
> >                 goto out;
> >         }
> >
> > +       drvdata->mode = mode;
>
> Given the way tmc_enable_etf_sink_perf() is called in
> tmc_enable_etf_sink(), I think it is time to get rid of the 'mode'
> parameter - it doesn't do anything nowadays.  Same thing for
> tmc_enable_etf_sink_sysfs() and ETR.

Sure, makes sense. I will clean it up.

> > @@ -279,8 +277,8 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
> >                 return;
> >         }
> >
> > +       drvdata->mode = CS_MODE_DISABLED;
> >         tmc_etf_disable_hw(drvdata);
> > -       local_set(&drvdata->mode, CS_MODE_DISABLED);
>
> I think setting the mode should come after tmc_etf_disable_hw(), as it
> was before.

You're right, I will change it.


Thanks for the review. Will send the updated series soon.

Cheers
Suzuki
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