Merge branch 'mlxsw-spectrum-prepare-for-xm-implementation-prefix-insertion-and-removal'

Ido Schimmel says:

====================
mlxsw: spectrum: Prepare for XM implementation - prefix insertion and removal

Jiri says:

This is a preparation patchset for follow-up support of boards with
extended mezzanine (XM), which is going to allow extended (scale-wise)
router offload.

XM requires a separate PRM register named XMDR to be used instead of
RALUE to insert/update/remove FIB entries. Therefore, this patchset
extends the previously introduces low-level ops to be able to have
XM-specific FIB entry config implementation.

Currently the existing original RALUE implementation is moved to "basic"
low-level ops.

Unlike legacy router, insertion/update/removal of FIB entries into XM
could be done in bulks up to 4 items in a single PRM register write.
That is why this patchset implements "an op context", that allows the
future XM ops implementation to squash multiple FIB events to single
register write. For that, the way in which the FIB events are processed
by the work queue has to be changed.

The conversion from 1:1 FIB event - work callback call to event queue is
implemented in patch #3.

Patch #4 introduces "an op context" that will allow in future to squash
multiple FIB events into one XMDR register write. Patch #12 converts it
from stack to be allocated per instance.

Existing RALUE manipulations are pushed to ops in patch #10.

Patch #13 is introducing a possibility for low-level implementation to
have per FIB entry private memory.

The rest of the patches are either cosmetics or smaller preparations.
====================

Link: https://lore.kernel.org/r/20201110094900.1920158-1-idosch@idosch.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>