[PATCH 0/9] net/dpaa2: NAPI-style Rx queue interrupts

[Maxime Leroy]

This series lets a dpaa2 worker sleep on a queue's data-availability
notification instead of busy-polling, exposed through the generic
rte_eth_dev_rx_intr_* API (NAPI-style: poll while frames keep coming,
arm the interrupt and sleep when the queue runs dry).

Why it is not a trivial .rx_queue_intr_enable
----------------------------------------------
A worker wakes on its software portal's DQRI, which fires when the
portal's DQRR holds frames. The default dpaa2 Rx burst pulls frames
from the FQ with a volatile dequeue and cannot be interrupt-driven; to
wake on the DQRI the FQ must instead be pushed to the portal's DQRR.

The natural dpni_set_queue with a notification destination would have to
target the worker's portal, but that portal is only known once a worker
affines, after dev_start, and that MC command holds the global MC lock
long enough to wedge the firmware while traffic runs. So the bind cannot
be done late, against the polling lcore.

Design
------
Each Rx FQ is bound to its own DPCON channel, statically, at dev_start
while the dpni is still disabled (no knowledge of the polling lcore). A
worker later subscribes its own ethrx portal to the channel and arms the
DQRI in rx_queue_intr_enable, a one-shot per-portal op, never the wedging
set_queue. One portal serves every queue a worker owns, so the DQRR
burst demuxes frames to their FQ by fqd_ctx; foreign frames are parked in
the target queue's stash, so the application polls all its queues after a
wakeup, the same scheduling contract as plain DPDK polling. A queue can
be re-homed to another lcore at runtime with no set_queue and no port
stop.

This reuses the event PMD's pushed/DQRR model but with one DPCON per FQ
and static affinity (no QBMan scheduling), so the DPCON allocator is
moved from the event driver to the fslmc bus and shared.

Patches 3 to 6 build the interrupt support proper, on top of three bug
fixes the path depends on and which it uncovered: patch 2 (eal, the
shared portal eventfd must not fail with -EEXIST), patch 7 (rx_queue_count
NULL on the primary process) and patch 8 (fast-path ops NULL after port
stop). They are real fixes, tagged for stable and backportable on their
own. Patches 1 (RSS RETA) and 9 (drop the software VLAN strip) are
independent net/dpaa2 changes the interrupt path does not require.

Tested on LX2160A (lx2160acex7).

Maxime Leroy (9):
  net/dpaa2: implement RSS RETA query and update
  eal/interrupts: keep real errno on epoll error
  bus/fslmc: move DPCON management from event driver to bus
  bus/fslmc/dpio: make the portal DQRI epoll optional
  net/dpaa2: support Rx queue interrupts
  bus/fslmc/dpio: tune DQRI interrupt coalescing holdoff
  net/dpaa2: fix Rx queue count for primary process
  ethdev: keep fast-path ops valid after port stop
  net/dpaa2: drop the fake software VLAN strip offload

 doc/guides/nics/dpaa2.rst                     |  10 +
 doc/guides/nics/features/dpaa2.ini            |   2 +
 doc/guides/rel_notes/release_26_07.rst        |   8 +
 drivers/bus/fslmc/meson.build                 |   1 +
 .../fslmc/portal}/dpaa2_hw_dpcon.c            |  16 +-
 drivers/bus/fslmc/portal/dpaa2_hw_dpio.c      | 113 +++-
 drivers/bus/fslmc/portal/dpaa2_hw_dpio.h      |  12 +
 drivers/bus/fslmc/portal/dpaa2_hw_pvt.h       |  35 +-
 .../fslmc/qbman/include/fsl_qbman_portal.h    |   9 +
 drivers/bus/fslmc/qbman/qbman_portal.c        |   7 +
 drivers/event/dpaa2/dpaa2_eventdev.h          |   5 +-
 drivers/event/dpaa2/meson.build               |   1 -
 drivers/net/dpaa2/base/dpaa2_hw_dpni.c        |  34 +-
 drivers/net/dpaa2/dpaa2_ethdev.c              | 556 +++++++++++++++++-
 drivers/net/dpaa2/dpaa2_ethdev.h              |  19 +
 drivers/net/dpaa2/dpaa2_rxtx.c                | 123 +++-
 lib/eal/include/rte_epoll.h                   |   3 +-
 lib/eal/linux/eal_interrupts.c                |  18 +-
 lib/ethdev/ethdev_private.c                   |   7 +
 19 files changed, 908 insertions(+), 71 deletions(-)
 rename drivers/{event/dpaa2 => bus/fslmc/portal}/dpaa2_hw_dpcon.c (90%)

-- 
2.43.0