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From:   Hariprasad Kelam <hkelam@marvell.com>
To:     Andrew Lunn <andrew@lunn.ch>
CC:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kuba@kernel.org" <kuba@kernel.org>,
        "davem@davemloft.net" <davem@davemloft.net>,
        Sunil Kovvuri Goutham <sgoutham@marvell.com>,
        Linu Cherian <lcherian@marvell.com>,
        Geethasowjanya Akula <gakula@marvell.com>,
        Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
        Subbaraya Sundeep Bhatta <sbhatta@marvell.com>
Subject: Re: [net-next PATCH 0/8] configuration support for switch headers &
 phy
Thread-Topic: [net-next PATCH 0/8] configuration support for switch headers &
 phy
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Date:   Tue, 23 Mar 2021 18:13:28 +0000
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Hi Andrew ,

Please see inline,


> -----Original Message-----
> From: Andrew Lunn <andrew@lunn.ch>
> Sent: Sunday, March 21, 2021 7:45 PM
> To: Hariprasad Kelam <hkelam@marvell.com>
> Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org; kuba@kernel.org=
;
> davem@davemloft.net; Sunil Kovvuri Goutham <sgoutham@marvell.com>;
> Linu Cherian <lcherian@marvell.com>; Geethasowjanya Akula
> <gakula@marvell.com>; Jerin Jacob Kollanukkaran <jerinj@marvell.com>;
> Subbaraya Sundeep Bhatta <sbhatta@marvell.com>
> Subject: [EXT] Re: [net-next PATCH 0/8] configuration support for switch
> headers & phy
>=20
> On Sun, Mar 21, 2021 at 05:39:50PM +0530, Hariprasad Kelam wrote:
> > This series of patches add support for parsing switch headers and
> > configuration support for phy modulation type(NRZ or PAM4).
> >
> > PHYs that support changing modulation type ,user can configure it
> > through private flags pam4.
> >
> > Marvell switches support DSA(distributed switch architecture) with
> > different switch headers like FDSA and EDSA. This patch series adds
> > private flags to enable user to configure interface in fdsa/edsa mode
> > such that flow steering (forwading packets to pf/vf depending on
> > switch header fields) and packet parsing can be acheived.
>=20
> Hi Hariprasad
>=20
> Private flags sound very wrong here. I would expect to see some integrati=
on
> between the switchdev/DSA driver and the MAC driver.
> Please show how this works in combination with drivers/net/dsa/mv88e6xxx
> or drivers/net/ethernet/marvell/prestera.
>=20
	Octeontx2 silicon supports NPC (network parser and cam) unit , through whi=
ch packet parsing and packet classification is achieved.
              Packet parsing extracting different fields from each layer.
				  DMAC + SMAC  --> LA
		                               VLAN ID --> LB
		                               SIP + DIP --> LC
                                                            TCP SPORT + DPO=
RT --> LD
    And packet classification is achieved through  flow identification in k=
ey extraction and mcam search key . User can install mcam rules
    With action as =20
		forward packet to PF and to receive  queue 0
		forward packet to VF and  with as RSS ( Receive side scaling)
		drop the packet=20
		etc..

   Now with switch header ( EDSA /FDSA) and HIGIG2 appended to regular pack=
et , NPC can not parse these
   Ingress packets as these headers does not have fixed headers. To achieve=
 this Special PKIND( port kind) is allocated in hardware
   which will help NPC to parse the packets.

 For example incase of EDSA 8 byte header which is placed right after SMAC =
, special PKIND reserved for EDSA helps NPC to=20
 Identify the  input packet is EDSA . Such that NPC can extract fields in t=
his header and forward to=20
 Parse rest of the headers.

 Same is the case with higig2 header where 16 bytes header is placed at sta=
rt of the packet.

In this case private flags helps user to configure interface in EDSA/FDSA o=
r HIGIG2. Such that special
PKIND reserved for that header are assigned to the interface.  The scope of=
 the patch series is how
User can configure interface mode as switch header(HIGIG2/EDSA etc) .In our=
 case no DSA logical
Ports are created as these headers can be stripped by NPC.

Thanks,
Hariprasad k
=20


> 	  Andrew