Re: [PATCH net v2 1/2] net: dsa: mv88e6xxx: fix 6351 family statistics snapshot

[Andrew Lunn]

On Mon, Oct 26, 2026 at 09:47:32AM -0700, Florian Fainelli wrote:
> The 88E6171, 88E6175, 88E6350 and 88E6351 take the port number in the
> low bits of the statistics operation register. The 6320 snapshot helper
> instead encodes the port as (port + 1) << 5. On an EA4500 with an
> 88E6171, this causes ethtool -S to return physical port 0's MIB counters
> for every user port. Traffic on other ports does not update their
> reported hardware counters.
> 
> Before the snapshot operation was moved into the chip operations, only
> the 6320 and 6352 families used the shifted encoding. The refactoring
> incorrectly assigned that encoding to all four 6351 family chips.
> 
> Use the unshifted snapshot helper for the entire 6351 family. This
> matches the Marvell DSDT statsCapture() implementation, which uses the
> raw port number for chips outside DEV_RMON_PORT_BITS, including these
> four chips.
> 
> The original 88E6171 change was tested on an EA4500: pings through
> different switch ports updated only the corresponding port's hardware
> counters. The other three chips have not been hardware tested.
> 
> Fixes: a605a0fe7115 ("net: dsa: mv88e6xxx: Abstract stats_snapshot into ops structure")
> Link: https://lore.kernel.org/all/404d5f2d-24a5-4edc-897b-b1b3c54a20e1@xxxxxxx/
> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>

Reviewed-by: Andrew Lunn <andrew@xxxxxxx>

    Andrew