From: Lukasz Majewski <lukma@denx.de>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Peng Fan <peng.fan@nxp.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Fugang Duan <fugang.duan@nxp.com>,
Shawn Guo <shawnguo@kernel.org>,
stefan.agner@toradex.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, krzk@kernel.org,
Vivien Didelot <vivien.didelot@gmail.com>,
NXP Linux Team <linux-imx@nxp.com>,
Jakub Kicinski <kuba@kernel.org>,
Vladimir Oltean <olteanv@gmail.com>,
Fabio Estevam <festevam@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 0/4] net: l2switch: Provide support for L2 switch on i.MX28 SoC
Date: Fri, 27 Nov 2020 10:25:28 +0100 [thread overview]
Message-ID: <20201127102528.33737ea4@jawa> (raw)
In-Reply-To: <20201127010811.GR2075216@lunn.ch>
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Hi Andrew,
> > > I would push back and say that the switch offers bridge
> > > acceleration for the FEC.
> >
> > Am I correct, that the "bridge acceleration" means in-hardware
> > support for L2 packet bridging?
>
> You should think of the hardware as an accelerator, not a switch. The
> hardware is there to accelerate what linux can already do. You setup a
> software bridge in linux, and then offload L2 switching to the
> accelerator. You setup vlans in linux, and then offload the filtering
> of them to the accelerator. If there is something linux can do, but
> the hardware cannot accelerate, you leave linux to do it in software.
Ok.
>
> > Do you propose to catch some kind of notification when user calls:
> >
> > ip link add name br0 type bridge; ip link set br0 up;
> > ip link set lan1 up; ip link set lan2 up;
> > ip link set lan1 master br0; ip link set lan2 master br0;
> > bridge link
> >
> > And then configure the FEC driver to use this L2 switch driver?
>
> That is what switchdev does. There are various hooks in the network
> stack which call into switchdev to ask it to offload operations to the
> accelerator.
Ok.
>
> > The differences from "normal" DSA switches:
> >
> > 1. It uses mapped memory (for its register space) for
> > configuration/statistics gathering (instead of e.g. SPI, I2C)
>
> That does not matter. And there are memory mapped DSA switches. The
> DSA framework puts no restrictions on how the control plane works.
>
> > (Of course the "Section 32.5.8.2" is not available)
>
> It is in the Vybrid datasheet :-)
Hmm...
I cannot find such chapter in the official documentation from NXP:
"VFxxx Controller Reference Manual, Rev. 0, 10/2016"
Maybe you have more verbose version? Could you share how the document
is named?
>
> Andrew
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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next prev parent reply other threads:[~2020-11-27 9:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-25 23:24 [RFC 0/4] net: l2switch: Provide support for L2 switch on i.MX28 SoC Lukasz Majewski
2020-11-25 23:24 ` [RFC 1/4] net: fec: Move some defines to ./drivers/net/ethernet/freescale/fec.h header Lukasz Majewski
2020-11-25 23:24 ` [RFC 2/4] net: dsa: Provide DSA driver for NXP's More Than IP L2 switch Lukasz Majewski
2020-11-25 23:24 ` [RFC 3/4] net: imx: l2switch: Adjust fec_main.c to provide support for " Lukasz Majewski
2020-11-25 23:24 ` [RFC 4/4] ARM: dts: imx28: Add description for L2 switch on XEA board Lukasz Majewski
2020-11-26 0:00 ` [RFC 0/4] net: l2switch: Provide support for L2 switch on i.MX28 SoC Andrew Lunn
2020-11-26 1:30 ` Florian Fainelli
2020-11-26 3:10 ` Andrew Lunn
2020-11-26 10:10 ` Lukasz Majewski
2020-11-26 14:45 ` Andrew Lunn
2020-11-27 0:03 ` Lukasz Majewski
2020-11-26 12:30 ` Vladimir Oltean
2020-11-26 23:35 ` Lukasz Majewski
2020-11-27 0:55 ` Andrew Lunn
2020-11-27 9:16 ` Lukasz Majewski
2020-11-27 1:08 ` Andrew Lunn
2020-11-27 9:25 ` Lukasz Majewski [this message]
2020-11-27 15:10 ` Andrew Lunn
2021-06-17 11:08 ` Lukasz Majewski
2021-06-17 13:57 ` Andrew Lunn
2020-11-27 19:29 ` Vladimir Oltean
2020-11-28 0:33 ` Lukasz Majewski
2020-11-28 4:34 ` Florian Fainelli
2020-11-29 21:59 ` Lukasz Majewski
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