Add support for nexthop routes for Marvell Prestera driver.
Subscribe on NEIGH_UPDATE events.

Add features:
 - Support connected route adding
   e.g.: "ip address add 1.1.1.1/24 dev sw1p1"
   e.g.: "ip route add 6.6.6/24 dev sw1p1"
 - Support nexthop route adding
   e.g.: "ip route add 5.5.5/24 via 1.1.1.2"
 - Support ECMP route adding
   e.g.: "ip route add 5.5.5/24 nexthop via 1.1.1.2 nexthop via 1.1.1.3"
 - Support "offload" and "trap" flags per each nexthop
 - Support "offload" flag for neighbours

Limitations:
 - Only "local" and "main" tables supported
 - Only generic interfaces supported for router (no bridges or vlans)

Flags meaning:
  ip route add 5.5.5/24 nexthop via 2.2.2.2 nexthop via 2.2.2.3
  ip route show
  ...
  5.5.5.0/24 rt_offload
        nexthop via 2.2.2.2 dev sw1p31 weight 1 trap
        nexthop via 2.2.2.3 dev sw1p31 weight 1 trap
  ...
  # When you just add route - lpm entry became occupied
  # in HW ("rt_offload" flag), but related to nexthops neighbours
  # still not resolved ("trap" flag).
  #
  # After some time...
  ip route show
  ...
  5.5.5.0/24 rt_offload
        nexthop via 2.2.2.2 dev sw1p31 weight 1 offload
        nexthop via 2.2.2.3 dev sw1p31 weight 1 offload
  ...
  # You will see, that appropriate neighbours was resolved and nexthop
  # entries occupied in HW too ("offload" flag)

Co-developed-by: Taras Chornyi <tchornyi@marvell.com>
Signed-off-by: Taras Chornyi <tchornyi@marvell.com>
Co-developed-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Yevhen Orlov <yevhen.orlov@plvision.eu>

Changes for v2:
* Add more reviewers in CC
* Check if route nexthop or direct with fib_nh_gw_family instead of fib_nh_scope
  This is needed after,
  747c14307214 ("ip: fix dflt addr selection for connected nexthop"),
  because direct route is now with the same scope as nexthop (RT_SCOPE_LINK)

Changes for v3:
* Resolve "unused functions" warnings, after
  patch ("net: marvell: prestera: Add heplers to interact ... "), and before
  patch ("net: marvell: prestera: Add neighbour cache accounting")

Changes for v4:
* Rebase to the latest master to resolve patch applying issues

Changes for v5:
* Repack structures to prevent holes
* Remove unused variables
* Fix misspeling issues

Changes for v6:
* Rebase on top of master
* Fix smatch warnings

Yevhen Orlov (9):
  net: marvell: prestera: Add router nexthops ABI
  net: marvell: prestera: Add cleanup of allocated fib_nodes
  net: marvell: prestera: Add strict cleanup of fib arbiter
  net: marvell: prestera: add delayed wq and flush wq on deinit
  net: marvell: prestera: Add length macros for prestera_ip_addr
  net: marvell: prestera: Add heplers to interact with fib_notifier_info
  net: marvell: prestera: add stub handler neighbour events
  net: marvell: prestera: Add neighbour cache accounting
  net: marvell: prestera: Propagate nh state from hw to kernel

 .../net/ethernet/marvell/prestera/prestera.h  |   12 +
 .../ethernet/marvell/prestera/prestera_hw.c   |  130 ++
 .../ethernet/marvell/prestera/prestera_hw.h   |   11 +
 .../ethernet/marvell/prestera/prestera_main.c |   11 +
 .../marvell/prestera/prestera_router.c        | 1141 ++++++++++++++++-
 .../marvell/prestera/prestera_router_hw.c     |  377 +++++-
 .../marvell/prestera/prestera_router_hw.h     |   76 +-
 7 files changed, 1716 insertions(+), 42 deletions(-)

-- 
2.17.1