net: ethernet: ti: am65-cpsw: add network flow classification support

Adds support for -N/--config-nfc ethtool command for
configuring RX classfiers.

Currently only raw Ethernet (flow-type ether) matching is added
based on source/destination addresses and VLAN Priority (PCP).

The ALE policer engine is used to perform the matching and routing to
a specific RX channel.

Test cases:

Increase number of RX channels to 8
ip link set end1 down
ip link set end0 down
ethtool -L end0 rx 8

1) Ether source address test
	ethtool -N end0 flow-type ether src xx:yy:zz:aa:bb:cc action 5

  Traffic from that address should route to channel 5

2) Ether destination address test
	ethtool -N eth0 flow-type ether dst yy:zz:aa:bb:cc:dd action 4

  Traffic to that address should route to channel 4

3) Drop test
	ethtool -N end0 flow-type ether src xx:yy:zz:aa:bb:cc action -1

  Traffic from that address should be dropped

4) VLAN PCP test

on Remote create VLAN with ID 5 and all traffic mapping to required priority to test. e.g. 7
	sudo ip link add link eno1 name eno1.5 type vlan id 5 egress-qos-map 0:7 1:7 2:7 3:7 4:7 5:7 6:7 7:7
	sudo ifconfig eno1.5 192.168.10.1

on DUT create VLAN with id 5
	ip link add link end0 name end0.5 type vlan id 5
	ifconfig end0.5 192.168.10.5

VLAN pcp 7 vid 5 route to RX channel 6
	ethtool -N end0 flow-type ether vlan 0xe005 action 6

  Traffic from that VLAN with PCP 7 should route to channel 6

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
Changes in v5:
- support RX_CLS_LOC_SPECIAL by plumbing our own logic of offering free classifier entires
  for rules when rule location is not specified by user.
- Updated commit log message for remove cpsw_ale_classifier_setup_default() on how
  traffic will behave by default.
- Link to v4: https://lore.kernel.org/r/20250514-am65-cpsw-rx-class-v4-...

Changes in v4:
- Added missing mutex_unlock in error case in am65_cpsw_rxnfc_add_rule()
- Stop using devm_ variant for kalloc/kfree for rxnfc rules as we explictly
  manage freeing.
- Dropped unnecessary print message in am65_cpsw_set_rxnfc()
- Link to v3: https://lore.kernel.org/r/20250513-am65-cpsw-rx-class-v3-...

Changes in v3:
- Fixed bug in cpsw_ale_policer_save/restore(). '* 4' is not needed for
  a u32 pointer.
- Fixed reverse Christmas tree order
- Moved mutex acquiring out of am65_cpsw_policer_find_match() and
  at beginning of am65_cpsw_rxnfc_add_rule()
- Link to v2: https://lore.kernel.org/r/20250505-am65-cpsw-rx-class-v2-...

Changes in v2:
- Error out if VLAN_ID > 0 as VLAN ID based flow routing still doesn't
   seem to work. Drop commented out code.
- Limit lines to 80 characters whereever possible.
- Change struct am65_cpsw_rxnfc_rule.location from int to unsigned int.
- Add information about order of rules evaluation and multiple matches
   in commit log.
- Link to v1: https://lore.kernel.org/r/20250319-am65-cpsw-rx-class-v1-...

---
Roger Quadros (9):
      net: ethernet: ti: cpsw_ale: Update Policer fields for more ALE size/ports
      net: ethernet: ti: cpsw_ale: return ALE index in cpsw_ale_add_vlan()
      net: ethernet: ti: cpsw_ale: return ALE index in cpsw_ale_vlan_add_modify()
      net: ethernet: ti: cpsw_ale: return ALE index in cpsw_ale_add_ucast()
      net: ethernet: ti: cpsw_ale: add cpsw_ale_policer_reset_entry()
      net: ethernet: ti: cpsw_ale: add cpsw_ale_policer_set/clr_entry()
      net: ethernet: ti: cpsw_ale: add policer save restore for PM sleep
      net: ethernet: ti: am65-cpsw: add network flow classification support
      net: ethernet: ti: am65-cpsw: remove cpsw_ale_classifier_setup_default()

 drivers/net/ethernet/ti/am65-cpsw-ethtool.c   | 395 ++++++++++++++++++++++++++
 drivers/net/ethernet/ti/am65-cpsw-nuss.c      |  32 ++-
 drivers/net/ethernet/ti/am65-cpsw-nuss.h      |  17 ++
 drivers/net/ethernet/ti/am65-cpsw-switchdev.c |   6 +-
 drivers/net/ethernet/ti/cpsw.c                |   4 +-
 drivers/net/ethernet/ti/cpsw_ale.c            | 214 +++++++++-----
 drivers/net/ethernet/ti/cpsw_ale.h            |  37 ++-
 drivers/net/ethernet/ti/cpsw_new.c            |   4 +-
 drivers/net/ethernet/ti/cpsw_switchdev.c      |   6 +-
 9 files changed, 622 insertions(+), 93 deletions(-)
---
base-commit: d1d7998df9d7d3ee20bcfc876065fa897b11506d
change-id: 20250305-am65-cpsw-rx-class-666006fab9dd

Best regards,
-- 
Roger Quadros <rogerq@kernel.org>