[PATCH v15 net-next 0/2] octeontx2-pf: mqprio bandwidth offload for NIX TX schedulers

This series adds hardware offload for channel-mode mqprio with
TC_MQPRIO_SHAPER_BW_RATE on Marvell octeontx2 PF devices. Each
non-QoS transmit queue is shaped by programming MDQ CIR/PIR on the NIX TX
scheduler. When bandwidth offload is active, the driver allocates one
SMQ per queue, parents every MDQ under TL4[0], and maps each traffic
class min/max rate to the queue(s) in that class.

The NIX TX scheduler hierarchy cannot be reprogrammed live today, so
mqprio add, replace, delete, and failed-replace rollback rebuild it by
bouncing the netdev through ndo_stop()/ndo_open(). That intentionally
drops in-flight traffic on each change. Before ndo_stop(), quiesce the
transmit path with dev_deactivate() so xmit cannot race queue teardown.
After a successful bounce on a running interface, reactivate TX queues
with dev_activate(). Cache the active rates and restore MDQ shapers from
otx2_mqprio_up() during ndo_open(); fail open if restoration fails.

Track mqprio configuration in mq_offload_snap snapshots (TC layout and
rates). On tc qdisc replace, stage the new configuration while keeping
the previous snapshot for rollback: failed setup restores the old
snapshot via netdev restart when the interface is running, successful
graft is recorded through TC_ROOT_GRAFT, and teardown of the replaced
qdisc instance commits the staged snapshot without tearing down the live
offload.

Patch 1 converts PF/VF and representor flag access to atomic bitops.
Patch 2 depends on it for safe OTX2_FLAG_INTF_DOWN and OTX2_FLAG_PORT_UP
updates on asynchronous mbox paths and during the mqprio netdev bounce.

The driver rejects offload unless the interface is running and the device
advertises CIR+PIR support. Per-TC rates are rejected when a traffic class
spans more than one queue. Concurrent PFC, XDP, SDP rep, or HTB use is
blocked, and ethtool channel count changes are blocked while mqprio
bandwidth offload is active.

Ratheesh Kannoth (2):
  octeontx2: use atomic bitops for PF/VF and rep flags
  octeontx2-pf: add mqprio bandwidth offload for NIX TX schedulers

 .../net/ethernet/marvell/octeontx2/af/rvu_nix.c    |   6 +-
 .../ethernet/marvell/octeontx2/nic/cn10k_ipsec.c   |   8 +-
 .../ethernet/marvell/octeontx2/nic/otx2_common.c   | 154 +++-
 .../ethernet/marvell/octeontx2/nic/otx2_common.h   | 100 ++-
 .../ethernet/marvell/octeontx2/nic/otx2_dcbnl.c    |   6 +
 .../ethernet/marvell/octeontx2/nic/otx2_devlink.c  |   2 +-
 .../ethernet/marvell/octeontx2/nic/otx2_ethtool.c  |  29 +-
 .../ethernet/marvell/octeontx2/nic/otx2_flows.c    |  34 +-
 .../net/ethernet/marvell/octeontx2/nic/otx2_pf.c   |  94 +--
 .../net/ethernet/marvell/octeontx2/nic/otx2_tc.c   | 776 ++++++++++++++++++++-
 .../net/ethernet/marvell/octeontx2/nic/otx2_txrx.c |  16 +-
 .../net/ethernet/marvell/octeontx2/nic/otx2_vf.c   |  10 +-
 .../net/ethernet/marvell/octeontx2/nic/otx2_xsk.c  |   4 +-
 drivers/net/ethernet/marvell/octeontx2/nic/qos.c   |  11 +
 .../net/ethernet/marvell/octeontx2/nic/qos_sq.c    |   4 +-
 drivers/net/ethernet/marvell/octeontx2/nic/rep.c   |  32 +-
 drivers/net/ethernet/marvell/octeontx2/nic/rep.h   |   3 +-
 17 files changed, 1138 insertions(+), 151 deletions(-)

---

v14 -> v15: Addressed sashiko comments.
- Split atomic PF/VF and representor flag access into a preparatory patch
  so mqprio netdev-restart and mbox paths can update OTX2_FLAG_INTF_DOWN
  and OTX2_FLAG_PORT_UP without data races on the shared flags word.
- Clear mqprio software state when hardware shaper teardown fails, warn,
  and still bounce the netdev on delete so offload does not remain stuck
  active after a mailbox error.
	https://lore.kernel.org/netdev/20260904031553.3196916-1-rkannoth@marvell.com/ (local)

v13 -> v14: Addressed sashiko comments.
- Quiesce TX with dev_deactivate() before ndo_stop() and dev_activate()
  after ndo_open() in otx2_mqprio_restart_netdev() to avoid xmit racing
  queue teardown.
- Use atomic set_bit()/clear_bit() for OTX2_FLAG_INTF_DOWN and
  OTX2_FLAG_PORT_UP updates on netdev-restart and mbox paths.
- Block concurrent mqprio bandwidth offload and HTB shaping.
- Fail ndo_open() if otx2_mqprio_up() cannot restore MDQ shapers.
- Rebuild the TX scheduler via netdev restart in otx2_mqprio_restore_old()
  when rolling back a failed replace on a running interface.
- Return an error from otx2_mqprio_down() if clearing hardware shapers
  fails instead of clearing software state anyway.
	https://lore.kernel.org/netdev/20260904031553.3196916-1-rkannoth@marvell.com/ (local)

v12 -> v13: Addressed sashiko comments.
	https://sashiko.dev/#/patchset/20260903023324.3078284-1-rkannoth%40marvell.com

v11 -> v12: Addressed sashiko comments.
	https://sashiko.dev/#/patchset/20260902015500.2985371-1-rkannoth%40marvell.com
v10 -> v11: Addressed sashiko comments.
	https://sashiko.dev/#/patchset/20260831131014.2639581-1-rkannoth%40marvell.com

v9 -> v10: Addressed sashiko/jacub comments.
	https://sashiko.dev/#/message/20260817032747.1765883-1-rkannoth%40marvell.com

v8 -> v9: Addressed Sashiko comments
	https://lore.kernel.org/netdev/aoJ6FhtWue0FHDQV@rkannoth-OptiPlex-7090/ (local)
v7 -> v8: Addressed Sashiko comments
	https://sashiko.dev/#/patchset/20260811085050.3212280-1-rkannoth%40marvell.com
v6 -> v7: Addressed Sashiko comments
	https://sashiko.dev/#/message/20260810034738.1786029-1-rkannoth%40marvell.com
v5 -> v6: Addressed Sashiko comments
	https://lore.kernel.org/netdev/20260806095434.1144397-1-rkannoth@marvell.com/ (local)
v4 -> v5: Addressed sashiko comments
	https://sashiko.dev/#/patchset/20260803042724.3380209-1-rkannoth%40marvell.com
v3 -> v4: Addressed sashiko comments
	https://lore.kernel.org/netdev/20260729105139.2302908-1-rkannoth@marvell.com/ (local)
v2 -> v3: Addressed sashiko comments
	https://lore.kernel.org/netdev/amnYX866mYx02cBe@rkannoth-OptiPlex-7090/T/#m67310cbec48b21c7720858ab3a1ea083a0f8dc10 (local)
v1 -> v2: Addressed sashiko comments
	https://lore.kernel.org/netdev/20260724075010.2665758-1-rkannoth@marvell.com/ (local)

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2.43.0