[PATCH net-next v4 0/3] dinghai: firmware handshake, MSI-X pools and async event queues

[han.junyang]

From: Junyang Han <han.junyang@xxxxxxxxxx>

This series continues the DingHai (ZXDH) PF driver bring-up: after PCI
probing, it verifies the firmware version contract, waits for the
RISC-V management core to become ready, sets up the MSI-X interrupt
pools, and creates the async event queues through which the firmware
will report events.

Some notes on the IRQ design:

The vector space is partitioned into per-purpose pools (async, RDMA,
vq). Event queues share a vector through an atomic notifier chain
attached to the IRQ, and the sharing degree is governed by pool
thresholds. The IRQ table hangs off a void *priv in the shared core
device: the PF, MPF and SF core devices each carry a different pool
layout behind that pointer, so a type-specific struct in en_pf.c keeps
the shared header free of PF-only details.

Changes in v4:
- Fold the irq and eq table create() steps into their init()
  counterparts and route every probe error path through the same
  destroy() functions remove() uses, so cleanup has a single
  authority from the start (review feedback on v3).
- Give the pool name a buffer bound of its own (16 bytes) instead of
  sharing the 100-byte IRQ name buffer, so W=1 builds stay clean of
  -Wformat-truncation (review feedback on v3).
- Lower the compat region wait from 200 s to 20 s: the firmware
  publishes the block within 10 s of boot, so twice that leaves
  margin, and the wait now sits far below the 180 s udev event
  window raised on the thread (review feedback on v3).
- Wait for the compat block with a per-field readiness check instead
  of only the first dword: the firmware fills the fields one by one,
  and a dword-granular check can read a half-populated block (the
  "single write" justification given in v3 was wrong).
- Log the legacy-firmware assumption when the compat region wait
  times out, making the intentionally ignored timeout visible.

Changes in v3:
- Unmap the modern config MMIO regions on the probe error paths added
  in this series; they used to leak when the fw compat check or the
  RISC-V readiness wait failed.
- Skip the RISC-V readiness wait for firmware without the compat
  region: the erased patch field read as 0xffff and defeated the skip.
- Make fw_minor unsigned so firmware minor versions >= 128 are not
  rejected through sign wrap.
- Balance the per-CPU IRQ accounting on release, so pool teardown does
  not trip its leftover WARN; set the IRQ affinity for real with
  irq_set_affinity_and_hint() instead of only updating the hint; name
  IRQs after their pool instead of a hardcoded prefix; assert that the
  pool is empty at free instead of force-releasing leftovers.
- Clear eq->irq when the async IRQ request fails, so teardown does not
  treat the ERR_PTR as a live IRQ.

Review findings not taken:

- xa_alloc() with a NULL entry does not fail: __xa_alloc() turns a
  NULL entry into the internal zero entry as a reservation
  (lib/xarray.c), which is the reservation semantics the pool relies
  on.
- BAR 0 length checks against a truncated bar: the bar layout is part
  of the board firmware contract and the driver does not defend
  against a broken device, as settled during the review of the
  earlier device bring-up series (Andrew Lunn).

Changes in v2:
- Convert both firmware readiness polls to readx_poll_timeout()
  (Andrew Lunn).
- Read the fw compat block field by field through ioread*() accessors
  instead of an ioread32_rep() bulk copy, which misplaces the u8/u16
  fields on big-endian; no __le annotations are needed since each
  accessor converts from little-endian (Andrew Lunn).
- Use kref for the IRQ reference count (Andrew Lunn).

Junyang Han (3):
  dinghai: add firmware version check and RISC-V readiness polling
  dinghai: add MSI-X interrupt pools
  dinghai: add async event queue for firmware notifications

 drivers/net/ethernet/zte/dinghai/Makefile   |   2 +-
 drivers/net/ethernet/zte/dinghai/en_pf.c    | 223 ++++++++++
 drivers/net/ethernet/zte/dinghai/en_pf.h    | 56 +++
 drivers/net/ethernet/zte/dinghai/zxdh_eq.c  | 137 +++++++
 drivers/net/ethernet/zte/dinghai/zxdh_eq.h  | 60 +++
 drivers/net/ethernet/zte/dinghai/zxdh_irq.c | 406 ++++++++++++++++++++
 drivers/net/ethernet/zte/dinghai/zxdh_irq.h | 73 ++++
 7 files changed, 956 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/ethernet/zte/dinghai/zxdh_eq.c
 create mode 100644 drivers/net/ethernet/zxdh_eq.h
 create mode 100644 drivers/net/ethernet/zxdh_irq.c
 create mode 100644 drivers/net/ethernet/zxdh_irq.h

--
2.27.0