Wed, Nov 30, 2016 at 07:09:27PM CET, andrew@lunn.ch wrote:

quoted

Something like that. I need to run routing protocols on the switch I/Fs and egress
pkgs on selected switch I/Fs bypassing ARP, just like DSA does with its vendor
tags.

Does the switch have an equivalent tagging protocol? If you are
building a tree of switches you need something like this for frames
going from the host via intermediate switches and out a specific port
on a remote switch.

quoted

We might have a tree as well so now I really wonder: Given we write a
proper switchdev driver, can it support switchtrees without touching
switchdev infra structure?

Jiri Pirko [off-list ref] is probably the best person to ask about
this. DSA hides the knowledge that there is multiple switches. To
switchdev, a tree of switches looks like one switch. This is not
because of switchdev, it is just the existing DSA code worked when
switchdev came along.

Looks like the hw is DSA-ish. If I'm not mistaken about that, should be
handled as a part of DSA.

If not I guess we will attach a physical

quoted

eth I/F to the switch and use both DSA and switchdev to support both trees
and HW offload. 

This only works if the switch has the necessary tagging protocol to
pass through multiple switches.

quoted

We have on an existing board with a BCM ROBO switch with lots of ports(>24),
managed over SPI. Looking at BCM DSA tag code it looks like it only supports
some 8 ports or so. I still have to find out if this is a limitation in BCM tagging
protocol or if just not impl. in DSA yet.

Hi Florian, care to comment?

As far as i understand, the tag used for SF2 and B53 does not support
a tree of switches. But the big ROBO switches might have a different
tagging protocol.

 Andrew