Re: [PATCH net-next 0/4] net: macb: Rework hardware timestamp configuration

[Nicolai Buchwitz <nb@tipi-net.de>]

Hi Kim

On 22.9.2026 11:10, Kim Wooseok via B4 Relay wrote:
> This started with two problems I found while using PTP hardware
> timestamping on a Raspberry Pi 5. A rejected RX filter could still
> change the TX one-step setting, and the PTPv1 Sync and Delay_Req 
> filters
> returned success without enabling RX timestamps.
> 
> This series reworks gem_set_hwtst() to validate the whole request 
> before
> programming the hardware. It calculates the settings locally, then
> updates the registers and saved configuration under bp->lock. With the
> register writes now in the setter, the two helpers are no longer 
> needed.
> 
> The remaining patches use the existing ALL fallback for the specific
> PTPv1 filters, turn off one-step mode for TX_OFF, and clear SRTSM when
> switching away from a PTPv2 filter. Each change is kept in its own 
> patch.
> 
> I compared the old and new behavior on the Pi 5. When I requested a TX
> mode change together with an invalid RX filter, the patched driver
> rejected the request without changing the saved settings or NCR. I
> also switched from one-step TX and PTPv2 RX to other settings and back.
> Only the relevant bits changed, and restoring the original settings
> restored NCR.
> 
> For the PTPv1 filters, I checked the effect by sending Sync and 
> Delay_Req
> packets over Ethernet. Before the change, the packets arrived without
> hardware timestamps. With the patches, the driver returned ALL and I
> could read the hardware timestamps from the received packets. PTPv2
> multicast reception continued to provide hardware timestamps, and
> selecting NONE disabled timestamping. I ran these tests with the 
> changes
> backported to the Pi's existing Linux 6.18.46 RT kernel.
> 
> On net-next, I built the series with ARM64 allyesconfig and 
> allmodconfig,
> both with W=1. Sparse reported no diagnostics in macb_ptp.c.
> 
> Assisted-by: GPT-6 Astra
> Signed-off-by: Kim Wooseok <5mghybrid@khu.ac.kr>
> ---
> Kim Wooseok (4):
>       net: macb: Preserve timestamp settings on rejected requests
>       net: macb: Enable RX timestamping for specific PTPv1 filters
>       net: macb: Disable one-step mode when TX timestamping is off
>       net: macb: Clear SRTSM outside PTPv2 receive filters
> 
>  drivers/net/ethernet/cadence/macb_ptp.c | 63 
> ++++++++++++---------------------
>  1 file changed, 23 insertions(+), 40 deletions(-)
> ---
> base-commit: 8830e65ed46de41f849eefb8ba227d4852c460f6
> change-id: 20260922-codex-macb-hwtstamp-submit-25ab4a2e6b94
> 
> Best regards,
> --
> Kim Wooseok <5mghybrid@khu.ac.kr>

For the series:

Tested-by: Nicolai Buchwitz <nb@tipi-net.de> # Raspberry Pi CM5 (macb 
rp1 with BCM54210PE)

Regards
Nicolai