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Date:   Thu, 27 Jul 2023 06:36:43 -0700
From:   Richard Cochran <richardcochran@gmail.com>
To:     Johannes Zink <j.zink@pengutronix.de>
Cc:     Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        patchwork-jzi@pengutronix.de, netdev@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kernel@pengutronix.de, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v2] net: stmmac: correct MAC propagation delay
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References: <20230719-stmmac_correct_mac_delay-v2-1-3366f38ee9a6@pengutronix.de>
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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.

Thanks,
Richard