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	id 1whbUM-00BPJK-HA; Thu, 09 Jul 2026 01:15:34 +0200
Date: Thu, 9 Jul 2026 01:15:34 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Daniel Golle <daniel@makrotopia.org>
Cc: Vladimir Oltean <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Simon Horman <horms@kernel.org>, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH RFC net-next 2/3] net: dsa: mxl862xx: add SMDIO clause-22
 register access
Message-ID: <98505e14-d684-4225-9415-f4d872113998@lunn.ch>
References: <ak0KJ6gUk2l_IwoI@makrotopia.org>
 <96c362d3-59d2-43c4-b2aa-c12dfeb6fcca@lunn.ch>
 <ak6o7Ovekjb_evPs@makrotopia.org>
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In-Reply-To: <ak6o7Ovekjb_evPs@makrotopia.org>

On Wed, Jul 08, 2026 at 09:45:48PM +0200, Daniel Golle wrote:
> On Wed, Jul 08, 2026 at 07:22:49PM +0200, Andrew Lunn wrote:
> > On Tue, Jul 07, 2026 at 04:16:07PM +0200, Daniel Golle wrote:
> > > Add mxl862xx_smdio_read() and mxl862xx_smdio_write() for clause-22
> > > SMDIO register access. MCUboot rescue mode only exposes clause-22
> > > registers; the existing clause-45 MMD interface is unavailable during
> > > firmware transfer. The MDIO bus lock is held per-transaction (not
> > > across polls) so that SB PDI polling during flash erase does not
> > > starve other MDIO users.
> > 
> > What other MDIO users are there? It sounds like once the switch is in
> > rescue mode, switch management is dead. So how can there be users?
> 
> The MDIO bus lock refers to the host bus which is used to connect
> the switch management interface. The same bus can also be used to
> connect other unrelated PHYs (eg. to provide a WAN or management
> interface independent of the switch).

Thanks for the explanation. Maybe 'does not starve other non-switch
MDIO users'?

I've not got to the rest of the patch yet, but i wondered if phylib
might still be trying to poll the switches PHYs.

	Andrew