Re: [PATCH v2] net: stmmac: correct MAC propagation delay

[Johannes Zink]

Hi Richard,

On 7/27/23 15:36, Richard Cochran wrote:
> On Thu, Jul 27, 2023 at 09:20:10AM +0200, Johannes Zink wrote:
> > Hi Richard,
> >
> > On 7/26/23 22:57, Richard Cochran wrote:
> > > On Mon, Jul 24, 2023 at 12:01:31PM +0200, Johannes Zink wrote:
> > >
> > > Earlier versions of the IP core return zero from these...
> > >
> > > > +#define	PTP_TS_INGR_LAT	0x68	/* MAC internal Ingress Latency */
> > > > +#define	PTP_TS_EGR_LAT	0x6c	/* MAC internal Egress Latency */
> >
> > good catch. Gonna send a v3 with a check to and set the values for dwmac v5 only.
>
> AFAICT there is no feature bit that indicates the presence or absence
> of these two registers.
>
> Are you sure that *all* v5 IP cores have these?
>
> I am not sure.

I cannot tell for sure either, since I have datasheets for the i.MX8MP only. 
Maybe Kurt has some insights here, as he has additional hardware available for 
testing?

Nevertheless, I am going to add a guard to only use the correction codepath on 
i.MX8MP in v3 for the time being, we can add other hardware later trivially if 
they support doing this.

Best regards
Johannes

> Thanks,
> Richard

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