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From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Sneh Shah <quic_snehshah@quicinc.com>,
	Andrew Halaney <ahalaney@redhat.com>,
	Vinod Koul <vkoul@kernel.org>,
	Bhupesh Sharma <bhupesh.sharma@linaro.org>,
	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>,
	netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel@quicinc.com
Subject: Re: [PATCH net-next] net: stmmac: dwmac-qcom-ethqos: Add support for 2.5G SGMII
Date: Wed, 29 May 2024 21:13:40 +0100	[thread overview]
Message-ID: <ZleMdFsmQzXGp1GM@shell.armlinux.org.uk> (raw)
In-Reply-To: <67553944-5d3f-4641-a719-da84554c0a9f@lunn.ch>

On Wed, May 29, 2024 at 04:28:16PM +0200, Andrew Lunn wrote:
> > Qualcomm ethernet HW supports 2.5G speed in overclocked SGMII mode.
> > we internally term it as OCSGMII.
> 
> So it still does SGMII inband signalling? Not 2500BaseX signalling? It
> is not actually compatible with 2500BaseX?
> 
> > End goal of these patches is to enable SGMII with 2.5G speed support.
> > The patch in these series enabled up SGMII with 2.5 for cases where we
> > don't have external phy. ( mac-to-mac connectivity)
> 
> So the other end needs to be an over clocked SGMII MAC, not 2500BaseX?
> 
> > The new patch posted extends this for the case when the MAC has an
> > external phy connected. ( hence we are advertising fr 2.5G speed by adding
> > 2500BASEX as supported interface in phylink)
> 
> And i assume it does not actually work against a true 2500BaseX
> device, because it is doing SGMII inband signalling?

I really hope the hardware isn't using any SGMII inband signalling
at 2.5G speeds. Other devices explicitly state that SGMII inband
signalling while operating the elevated 2.5G speed is *not* supported!

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

WARNING: multiple messages have this Message-ID (diff)
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Sneh Shah <quic_snehshah@quicinc.com>,
	Andrew Halaney <ahalaney@redhat.com>,
	Vinod Koul <vkoul@kernel.org>,
	Bhupesh Sharma <bhupesh.sharma@linaro.org>,
	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>,
	netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel@quicinc.com
Subject: Re: [PATCH net-next] net: stmmac: dwmac-qcom-ethqos: Add support for 2.5G SGMII
Date: Wed, 29 May 2024 21:13:40 +0100	[thread overview]
Message-ID: <ZleMdFsmQzXGp1GM@shell.armlinux.org.uk> (raw)
In-Reply-To: <67553944-5d3f-4641-a719-da84554c0a9f@lunn.ch>

On Wed, May 29, 2024 at 04:28:16PM +0200, Andrew Lunn wrote:
> > Qualcomm ethernet HW supports 2.5G speed in overclocked SGMII mode.
> > we internally term it as OCSGMII.
> 
> So it still does SGMII inband signalling? Not 2500BaseX signalling? It
> is not actually compatible with 2500BaseX?
> 
> > End goal of these patches is to enable SGMII with 2.5G speed support.
> > The patch in these series enabled up SGMII with 2.5 for cases where we
> > don't have external phy. ( mac-to-mac connectivity)
> 
> So the other end needs to be an over clocked SGMII MAC, not 2500BaseX?
> 
> > The new patch posted extends this for the case when the MAC has an
> > external phy connected. ( hence we are advertising fr 2.5G speed by adding
> > 2500BASEX as supported interface in phylink)
> 
> And i assume it does not actually work against a true 2500BaseX
> device, because it is doing SGMII inband signalling?

I really hope the hardware isn't using any SGMII inband signalling
at 2.5G speeds. Other devices explicitly state that SGMII inband
signalling while operating the elevated 2.5G speed is *not* supported!

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2024-05-29 20:13 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-18  7:11 [PATCH net-next] net: stmmac: dwmac-qcom-ethqos: Add support for 2.5G SGMII Sneh Shah
2023-12-18  7:11 ` Sneh Shah
2023-12-18 14:21 ` Maxime Chevallier
2023-12-18 14:21   ` Maxime Chevallier
2023-12-18 14:32   ` Sneh Shah
2023-12-18 14:32     ` Sneh Shah
2023-12-18 16:20 ` Andrew Halaney
2023-12-18 16:20   ` Andrew Halaney
2023-12-18 16:31   ` Andrew Halaney
2023-12-18 16:31     ` Andrew Halaney
2023-12-20  7:32   ` Sneh Shah
2023-12-20  7:32     ` Sneh Shah
2023-12-20 15:59     ` Andrew Halaney
2023-12-20 15:59       ` Andrew Halaney
2023-12-21  8:53       ` Sneh Shah
2023-12-21  8:53         ` Sneh Shah
2023-12-21 14:30         ` Andrew Halaney
2023-12-21 14:30           ` Andrew Halaney
2023-12-21 16:58           ` [Linux-stm32] " Maxime Chevallier
2023-12-21 16:58             ` Maxime Chevallier
2024-05-26 16:27         ` Russell King (Oracle)
2024-05-26 16:27           ` Russell King (Oracle)
2024-05-28 22:35           ` Andrew Halaney
2024-05-28 22:35             ` Andrew Halaney
2024-05-29 14:13           ` Sneh Shah
2024-05-29 14:13             ` Sneh Shah
2024-05-29 14:28             ` Andrew Lunn
2024-05-29 14:28               ` Andrew Lunn
2024-05-29 20:13               ` Russell King (Oracle) [this message]
2024-05-29 20:13                 ` Russell King (Oracle)
2024-06-03 11:15                 ` Sneh Shah
2024-06-03 11:15                   ` Sneh Shah
2024-05-29 20:09             ` Russell King (Oracle)
2024-05-29 20:09               ` Russell King (Oracle)
2024-06-03 11:27               ` Sneh Shah
2024-06-03 11:27                 ` Sneh Shah
2024-06-03 13:12                 ` Russell King (Oracle)
2024-06-03 13:12                   ` Russell King (Oracle)

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