Re: [RFC PATCH 15/40] soundwire: cadence_master: handle multiple status reports per Slave

[Pierre-Louis Bossart]

On 8/2/19 7:20 AM, Vinod Koul wrote:
> On 25-07-19, 18:40, Pierre-Louis Bossart wrote:
> > When a Slave reports multiple status in the sticky bits, find the
> > latest configuration from the mirror of the PING frame status and
> > update the status directly.
> >
> > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/soundwire/cadence_master.c | 34 ++++++++++++++++++++++++------
> >   1 file changed, 28 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
> > index 889fa2cd49ae..25d5c7267c15 100644
> > --- a/drivers/soundwire/cadence_master.c
> > +++ b/drivers/soundwire/cadence_master.c
> > @@ -643,13 +643,35 @@ static int cdns_update_slave_status(struct sdw_cdns *cdns,
> >   
> >   		/* first check if Slave reported multiple status */
> >   		if (set_status > 1) {
> > +			u32 val;
> > +
> >   			dev_warn_ratelimited(cdns->dev,
> > -					     "Slave reported multiple Status: %d\n",
> > -					     mask);
> > -			/*
> > -			 * TODO: we need to reread the status here by
> > -			 * issuing a PING cmd
> > -			 */
> > +					     "Slave %d reported multiple Status: %d\n",
> > +					     i, mask);
> > +
> > +			/* re-check latest status extracted from PING commands */
> > +			val = cdns_readl(cdns, CDNS_MCP_SLAVE_STAT);
> > +			val >>= (i * 2);
> > +
> > +			switch (val & 0x3) {
> > +			case 0:
>
> why not case CDNS_MCP_SLAVE_INTSTAT_NPRESENT:

ok

> > +				status[i] = SDW_SLAVE_UNATTACHED;
> > +				break;
> > +			case 1:
> > +				status[i] = SDW_SLAVE_ATTACHED;
> > +				break;
> > +			case 2:
> > +				status[i] = SDW_SLAVE_ALERT;
> > +				break;
> > +			default:
> > +				status[i] = SDW_SLAVE_RESERVED;
> > +				break;
> > +			}
>
> we have same logic in the code block preceding this, maybe good idea to
> write a helper and use for both

Yes, I am thinking about this. There are multiple cases where we want to 
re-check the status and clear some bits, so helpers would be good.

> Also IIRC we can have multiple status set right?

Yes, the status bits are sticky and mirror all values reported in PING 
frames. I am still working on how to clear those bits, there are cases 
where we clear bits and end-up never hearing from that device ever 
again. classic edge/level issue I suppose.