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author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2021-03-16 12:24:17 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2021-03-16 23:13:45 +0100 |
commit | 6e9530f4c0429ac4d8f58743f047cb67a7e74c35 (patch) | |
tree | 4e92d2e2a35b7298d57bb44fffeaaa7c67fa992d /Documentation/networking/dsa | |
parent | Documentation: networking: dsa: add paragraph for the MRP offload (diff) | |
download | linux-6e9530f4c0429ac4d8f58743f047cb67a7e74c35.tar.xz linux-6e9530f4c0429ac4d8f58743f047cb67a7e74c35.zip |
Documentation: networking: dsa: add paragraph for the HSR/PRP offload
Add a short summary of the methods that a driver writer must implement
for offloading a HSR/PRP network interface.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking/dsa')
-rw-r--r-- | Documentation/networking/dsa/dsa.rst | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/networking/dsa/dsa.rst b/Documentation/networking/dsa/dsa.rst index 0daafa2fb9eb..69040e11ee5e 100644 --- a/Documentation/networking/dsa/dsa.rst +++ b/Documentation/networking/dsa/dsa.rst @@ -787,6 +787,38 @@ 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 discovery of 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 are not implemented (therefore, bridging a hsr network +interface with a physical switch port does not produce the expected result). + +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 ==== |