On Sun, Feb 21, 2021 at 3:34 PM Vladimir Oltean <olte...@gmail.com> wrote: > > From: Vladimir Oltean <vladimir.olt...@nxp.com> > > Add a short summary of the methods that a driver writer must implement > for offloading a HSR/PRP network interface. > > Cc: George McCollister <george.mccollis...@gmail.com> > Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com> > --- > Documentation/networking/dsa/dsa.rst | 32 ++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/Documentation/networking/dsa/dsa.rst > b/Documentation/networking/dsa/dsa.rst > index bf82f2aed29a..277045346f3a 100644 > --- a/Documentation/networking/dsa/dsa.rst > +++ b/Documentation/networking/dsa/dsa.rst > @@ -760,6 +760,38 @@ to work properly. The operations are detailed below. > which MRP PDUs should be trapped to software and which should be > autonomously > forwarded. > > +IEC 62439-3 (HSR/PRP) > +--------------------- > + > +The Parallel Redundancy Protocol (PRP) is a network redundancy protocol which > +works by duplicating and sequence numbering packets through two independent > L2 > +networks (which are unaware of the PRP tail tags carried in the packets), and > +eliminating the duplicates at the receiver. The High-availability Seamless > +Redundancy (HSR) protocol is similar in concept, except all nodes that carry > +the redundant traffic are aware of the fact that it is HSR-tagged (because > HSR > +uses a header with an EtherType of 0x892f) and are physically connected in a > +ring topology. Both HSR and PRP use supervision frames for monitoring the > +health of the network and for discovering the other nodes. > + > +In Linux, both HSR and PRP are implemented in the hsr driver, which > +instantiates a virtual, stackable network interface with two member ports. > +The driver only implements the basic roles of DANH (Doubly Attached Node > +implementing HSR) and DANP (Doubly Attached Node implementing PRP); the roles > +of RedBox and QuadBox aren't (therefore, bridging a hsr network interface > with > +a physical switch port is not supported). > + > +A driver which is able of offloading certain functions of a DANP or DANH > should > +declare the corresponding netdev features as indicated by the documentation > at > +``Documentation/networking/netdev-features.rst``. Additionally, the following > +methods must be implemented: > + > +- ``port_hsr_join``: function invoked when a given switch port is added to a > + DANP/DANH. The driver may return ``-EOPNOTSUPP`` and in this case, DSA will > + fall back to a software implementation where all traffic from this port is > + sent to the CPU. > +- ``port_hsr_leave``: function invoked when a given switch port leaves a > + DANP/DANH and returns to normal operation as a standalone port. > + > TODO > ==== > > -- > 2.25.1 >
Reviewed-by: George McCollister <george.mccollis...@gmail.com>
