[Intel-wired-lan] [PATCH net v2 2/5] renesas: reject PTP_STRICT_FLAGS as unsupported

[Simon Horman]

On Wed, Mar 12, 2025 at 03:15:51PM -0700, Jacob Keller wrote:
> The ravb_ptp_extts() function checks the flags coming from the
> PTP_EXTTS_REQUEST ioctl, to ensure that future flags are not accepted on
> accident.
> 
> This was updated to 'honor' the PTP_STRICT_FLAGS in commit 6138e687c7b6
> ("ptp: Introduce strict checking of external time stamp options.").
> However, the driver does not *actually* validate the flags.
> 
> I originally fixed this driver to reject future flags in commit
> 592025a03b34 ("renesas: reject unsupported external timestamp flags"). It
> is still unclear whether this hardware timestamps the rising, falling, or
> both edges of the input signal.
> 
> Accepting requests with PTP_STRICT_FLAGS is a bug, as this could lead to
> users mistakenly assuming a request with PTP_RISING_EDGE actually
> timestamps the rising edge only.
> 
> Reject requests with PTP_STRICT_FLAGS (and hence all PTP_EXTTS_REQUEST2
> requests) until someone with access to the datasheet or hardware knowledge
> can confirm the timestamping behavior and update this driver.
> 
> Fixes: 6138e687c7b6 ("ptp: Introduce strict checking of external time stamp options.")
> Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>

Reviewed-by: Simon Horman <horms at kernel.org>