[net,v2,0/5] net: ptp: fix egregious supported flag checks

Message

Jacob Keller March 12, 2025, 10:15 p.m. UTC

In preparation for adding .supported_extts_flags and
.supported_perout_flags to the ptp_clock_info structure, fix a couple of
places where drivers get existing flag gets grossly incorrect.

The igb driver claims 82580 supports strictly validating PTP_RISING_EDGE
and PTP_FALLING_EDGE, but doesn't actually check the flags. Fix the driver
to require that the request match both edges, as this is implied by the
datasheet description.

The renesas driver also claims to support strict flag checking, but does
not actually check the flags either. I do not have the data sheet for this
device, so I do not know what edge it timestamps. For simplicity, just
reject all requests with PTP_STRICT_FLAGS. This essentially prevents the
PTP_EXTTS_REQUEST2 ioctl from working. Updating to correctly validate the
flags will require someone who has the hardware to confirm the behavior.

The lan743x driver supports (and strictly validates) that the request is
either PTP_RISING_EDGE or PTP_FALLING_EDGE but not both. However, it does
not check the flags are one of the known valid flags. Thus, requests for
PTP_EXT_OFF (and any future flag) will be accepted and misinterpreted. Add
the appropriate check to reject unsupported PTP_EXT_OFF requests and future
proof against new flags.

The broadcom PHY driver checks that PTP_PEROUT_PHASE is not set. This
appears to be an attempt at rejecting unsupported flags. It is not robust
against flag additions such as the PTP_PEROUT_ONE_SHOT, or anything added
in the future. Fix this by instead checking against the negation of the
supported PTP_PEROUT_DUTY_CYCLE instead.

The ptp_ocp driver supports PTP_PEROUT_PHASE and PTP_PEROUT_DUTY_CYCLE, but
does not check unsupported flags. Add the appropriate check to ensure
PTP_PEROUT_ONE_SHOT and any future flags are rejected as unsupported.

These are changes compile-tested, but I do not have hardware to validate the
behavior.

There are a number of other drivers which enable periodic output or
external timestamp requests, but which do not check flags at all. We could
go through each of these drivers one-by-one and meticulously add a flag
check. Instead, these drivers will be covered only by the upcoming
.supported_extts_flags and .supported_perout_flags checks in a net-next
series.

Signed-off-by: Jacob Keller <[e-mail]>
---
Changes in v2:
- Drop Raju Lakkaraju from Cc since his email appears to no longer deliver.
- Fix the igb 82580 check to allow disabling the pin without flags set.
- Link to v1: https://lore.kernel.org/r/[e-mail]

---
Jacob Keller (5):
      igb: reject invalid external timestamp requests for 82580-based HW
      renesas: reject PTP_STRICT_FLAGS as unsupported
      net: lan743x: reject unsupported external timestamp requests
      broadcom: fix supported flag check in periodic output function
      ptp: ocp: reject unsupported periodic output flags

 drivers/net/ethernet/intel/igb/igb_ptp.c     | 6 ++++++
 drivers/net/ethernet/microchip/lan743x_ptp.c | 6 ++++++
 drivers/net/ethernet/renesas/ravb_ptp.c      | 3 +--
 drivers/net/phy/bcm-phy-ptp.c                | 3 ++-
 drivers/ptp/ptp_ocp.c                        | 4 ++++
 5 files changed, 19 insertions(+), 3 deletions(-)
---
base-commit: 992ee3ed6e9fdd0be83a7daa5ff738e3cf86047f
change-id: 20250310-jk-net-fixes-supported-extts-flags-e8434d8e2552

Best regards,