RE: [RFC] Support for SGMII 2500

[Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>]

Hi Madalin,

> -----Original Message-----
> From: Bhaskar Upadhaya
> Sent: Tuesday, November 28, 2017 12:57 PM
> To: Madalin-cristian Bucur <madalin.bucur@nxp.com>; Andrew Lunn
> <andrew@lunn.ch>; f.fainelli@gmail.com; netdev@vger.kernel.org; Anji
> Jagarlmudi <anji.jagarlmudi@nxp.com>; Calvin Johnson
> <calvin.johnson@nxp.com>; Prabhakar Kushwaha
> <prabhakar.kushwaha@nxp.com>; Poonam Aggrwal
> <poonam.aggrwal@nxp.com>
> Cc: Shengzhou Liu <shengzhou.liu@nxp.com>; York Sun <york.sun@nxp.com>; u-
> boot@lists.denx.de
> Subject: RE: [RFC] Support for SGMII 2500
> 
> + Anji, Calvin, Prabhakar, Poonam.
> 
> -----Original Message-----
> From: Madalin-cristian Bucur
> Sent: Tuesday, November 28, 2017 12:56 PM
> To: Andrew Lunn <andrew@lunn.ch>; f.fainelli@gmail.com;
> netdev@vger.kernel.org
> Cc: Bhaskar Upadhaya <bhaskar.upadhaya@nxp.com>; Shengzhou Liu
> <shengzhou.liu@nxp.com>; York Sun <york.sun@nxp.com>; u-
> boot@lists.denx.de
> Subject: [RFC] Support for SGMII 2500
> 
> Hi,
> 
> There is a disconnect between the SGMII 2500 support in u-boot and Linux.
> Bhaskar is trying to add support for a SGMII interface working at 2.5Gbps by
> using the PHY connection type "sgmii-2500" in the device tree:
> 
> 	phy-connection-type = "sgmii-2500";
> 
> This is supported by u-boot, in include/phy.h:
> 
> 	typedef enum {
> 	        PHY_INTERFACE_MODE_MII,
> 	        PHY_INTERFACE_MODE_GMII,
> 	        PHY_INTERFACE_MODE_SGMII,
> 	        PHY_INTERFACE_MODE_SGMII_2500,
> 	...
> 
> 	static const char *phy_interface_strings[] = {
> 	        [PHY_INTERFACE_MODE_MII]                = "mii",
> 	        [PHY_INTERFACE_MODE_GMII]               = "gmii",
> 	        [PHY_INTERFACE_MODE_SGMII]              = "sgmii",
> 	        [PHY_INTERFACE_MODE_SGMII_2500]         = "sgmii-2500",
> 	...
> 
> since this commit:
> 
> 	commit c35f8693942d8284c635592f263a0fe11abe1d1d
> 	Author: Shengzhou Liu <Shengzhou.Liu@freescale.com>
> 	Date:   Thu Oct 23 17:20:57 2014 +0800
> 
> 	    net/fm: add 2.5G SGMII support
> 
> 	    As auto-negotiation is not supported for 2.5G SGMII, we need
> 	    to add a new type PHY_INTERFACE_MODE_SGMII_2500 to
> differentiate
> 	    SGMII-1G and SGMII-2.5G with different setting for auto-negotiation.
> 
> 	    Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
> 	    Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
> 	    Reviewed-by: York Sun <yorksun@freescale.com>
> 
> In the Linux kernel we do not have a separate define for SGMII_2500, should we
> add something like the change below?
> 

If there is no separate define in Linux. Than how it deals with auto-negotiation.
Can same approach be used in u-boot?

--pk