Re: [PATCH] coresight: replicator: Reset replicator if context is lost

[Sai Prakash Ranjan]

Hi Mathieu,

On 2020-05-11 21:49, Mathieu Poirier wrote:
> Hi Sai,
>
> On Mon, 11 May 2020 at 02:34, Sai Prakash Ranjan
> <saiprakash.ranjan@xxxxxxxxxxxxxx> wrote:
> > On some QCOM SoCs, replicators in Always-On domain loses its
> > context as soon as the clock is disabled. Currently as a part
> > of pm_runtime workqueue, clock is disabled after the replicator
> > is initialized by amba_pm_runtime_suspend assuming that context
> > is not lost which is not true for replicators with such
> > limitations. Hence check the replicator idfilter registers
> > in dynamic_replicator_enable() and reset again.
> >
> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> > ---
> >
> > More info here - https://lore.kernel.org/patchwork/patch/1231182/
> >
> > ---
> >  drivers/hwtracing/coresight/coresight-replicator.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-replicator.c 
> > b/drivers/hwtracing/coresight/coresight-replicator.c
> > index e7dc1c31d20d..11df63f51071 100644
> > --- a/drivers/hwtracing/coresight/coresight-replicator.c
> > +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> > @@ -68,6 +68,17 @@ static int dynamic_replicator_enable(struct 
> > replicator_drvdata *drvdata,
> >         int rc = 0;
> >         u32 reg;
> >
> > +       /*
> > +        * On some QCOM SoCs with replicators in Always-On domain, 
> > disabling
> > +        * clock will result in replicator losing its context. 
> > Currently
> > +        * as a part of pm_runtime workqueue, amba_pm_runtime_suspend 
> > disables
> > +        * clock assuming the context is not lost which is not true 
> > for cases
> > +        * with hardware limitations as the above.
> > +        */
> > +       if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0) 
> > &&
> > +           (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) == 
> > 0))
> > +               dynamic_replicator_reset(drvdata);
> > +
>
> Based on your comment here[1] and the ongoing conversation, I will
> wait for a V2.
>
> Thanks,
> Mathieu
>
> [1]. https://lkml.org/lkml/2020/5/11/650

Yes, I will post a v2 once we have consensus regarding which way we need 
to
add a workaround for such QCOM SoCs.

Thanks,
Sai

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