Re: [PATCH v2] net: dsa: mv88e6xxx: Fix port_hidden_wait to account for port_base_addr

From: Marek Behún
Date: Sun Apr 24 2022 - 15:35:52 EST

On Sun, 24 Apr 2022 21:26:58 +0200
Andrew Lunn <andrew@xxxxxxx> wrote:

> On Sun, Apr 24, 2022 at 03:31:43PM +0000, Nathan Rossi wrote:
> > The other port_hidden functions rely on the port_read/port_write
> > functions to access the hidden control port. These functions apply the
> > offset for port_base_addr where applicable. Update port_hidden_wait to
> > use the port_wait_bit so that port_base_addr offsets are accounted for
> > when waiting for the busy bit to change.
> >
> > Without the offset the port_hidden_wait function would timeout on
> > devices that have a non-zero port_base_addr (e.g. MV88E6141), however
> > devices that have a zero port_base_addr would operate correctly (e.g.
> > MV88E6390).
> >
> > Fixes: ea89098ef9a5 ("net: dsa: mv88x6xxx: mv88e6390 errata")
> That is further back than needed. And due to the code moving around
> and getting renamed, you are added extra burden on those doing the
> back port for no actual gain.
> Please verify what i suggested, 609070133aff1 is better and then
> repost.

The bug was introduced by ea89098ef9a5.
609070133aff1 is only requirement for this fix, but Fixes tag should reference
the commit which introduced the bug, afaik.

So it should be

Fixes: ea89098ef9a5 ("net: dsa: mv88x6xxx: mv88e6390 errata")
Cc: stable@xxxxxxxxxxxxxxx # 609070133aff ("net: dsa: mv88e6xxx: update code operating on hidden registers")