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Date:   Sun, 24 Apr 2022 16:52:28 +0200
From:   Marek =?UTF-8?B?QmVow7pu?= <kabel@kernel.org>
To:     Nathan Rossi <nathan@nathanrossi.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH] net: dsa: mv88e6xxx: Fix port_hidden_wait to account
 for port_base_addr
Message-ID: <20220424165228.4030aea6@thinkpad>
In-Reply-To: <20220424141759.315303-1-nathan@nathanrossi.com>
References: <20220424141759.315303-1-nathan@nathanrossi.com>
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On Sun, 24 Apr 2022 14:17:59 +0000
Nathan Rossi <nathan@nathanrossi.com> 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).

So basically the code is accessing the wrong register for devices with
non-zero port_base_addr. This means that the patch should have a Fixes
tag with the commit that introduced this bug, so that it gets
backported to relevant stable versions.

Could you resend with Fixes tag?

Marek