Re: [PATCH V2 1/3] Documentation: devicetree: add multiple cpu port DSA binding
From: Rob Herring
Date: Wed Jun 07 2017 - 17:10:08 EST
On Tue, May 30, 2017 at 02:32:29PM -0700, Florian Fainelli wrote:
> On 05/30/2017 03:44 AM, John Crispin wrote:
> > Extend the DSA binding documentation, adding the new property required
> > when there is more than one CPU port attached to the switch.
> >
> > Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> > Cc: devicetree@xxxxxxxxxxxxxxx
> > Signed-off-by: John Crispin <john@xxxxxxxxxxx>
> > ---
> > Documentation/devicetree/bindings/net/dsa/dsa.txt | 61 ++++++++++++++++++++++-
> > 1 file changed, 60 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/devicetree/bindings/net/dsa/dsa.txt b/Documentation/devicetree/bindings/net/dsa/dsa.txt
> > index cfe8f64eca4f..c164eb38ccc5 100644
> > --- a/Documentation/devicetree/bindings/net/dsa/dsa.txt
> > +++ b/Documentation/devicetree/bindings/net/dsa/dsa.txt
> > @@ -55,6 +55,11 @@ A user port has the following optional property:
> > - label : Describes the label associated with this port, which
> > will become the netdev name.
> >
> > +- cpu : Option for non "cpu"/"dsa" ports. A phandle to a
> > + "cpu" port, which will be used for passing packets
> > + from this port to the host. If not present, the first
> > + "cpu" port will be used.
>
> So this option essentially allow us to "partition" the switch between
> vectors of ports and their upstream/CPU port.
Could this be more generic? This is basically saying route all packets
on this port to another port. Maybe there's some usecase to route to
non-cpu ports?
> While using Device Tree is an obvious choice for making the initial
> partitioning, it seems like we are missing a configuration mechanism
> whereby we can properly assign ports to a specific upstream CPU port.
What determines how things are routed/partitioned? If it is purely user
choice then I don't think this should be in DT.
> Let's move the actual discussion into patch 2 in order not to pollute
> the DT maintainers' inbox.