mlxsw: spectrum_port_range: Add devlink resource support

Expose via devlink-resource the maximum number of port range registers
and their current occupancy. Besides the observability benefits, this
resource will be used by subsequent patches for scale and occupancy
tests.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/7945e0c715dc5efb1617f45f7560c1f1bd0bcf8a.1689092769.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: spectrum_port_range: Add port range core

The Spectrum ASICs have a fixed number of port range registers, each of
which maintains the following parameters:

* Minimum and maximum port.
* Apply port range for source port, destination port or both.
* Apply port range for TCP, UDP or both.
* Apply port range for IPv4, IPv6 or both.

Implement a port range core which takes care of the allocation and
configuration of these registers and exposes an API that allows
in-driver consumers (e.g., the ACL code) to request matching on a range
of either source or destination port.

These registers are going to be used for port range matching in the
flower classifier that already matches on EtherType being IPv4 / IPv6 and
IP protocol being TCP / UDP. As such, there is no need to limit these
registers to a specific EtherType or IP protocol, which will increase
the likelihood of a register being shared by multiple flower filters.

It is unlikely that a filter will match on the same range of both source
and destination ports, which is why each register is only configured to
match on either source or destination port. If a filter requires
matching on a range of both source and destination ports, it will
utilize two port range registers and match on the output of both.

For efficient lookup and traversal, use XArray to store the allocated
port range registers. The XArray uses RCU and an internal spinlock to
synchronise access, so there is no need for a dedicate lock.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/674f00539a0072d455847663b5feb504db51a259.1689092769.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>