Messages in this thread | | | Date | Tue, 20 Oct 2020 15:15:25 +0100 | From | Russell King - ARM Linux admin <> | Subject | Re: [PATCH v3 1/3] net: dsa: mv88e6xxx: Don't force link when using in-band-status |
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On Tue, Oct 20, 2020 at 04:05:35PM +0200, Andrew Lunn wrote: > On Tue, Oct 20, 2020 at 03:49:40PM +0200, Marek Behun wrote: > > On Tue, 20 Oct 2020 11:15:52 +0100 > > Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote: > > > > > On Tue, Oct 20, 2020 at 04:45:56PM +1300, Chris Packham wrote: > > > > When a port is configured with 'managed = "in-band-status"' don't force > > > > the link up, the switch MAC will detect the link status correctly. > > > > > > > > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> > > > > Reviewed-by: Andrew Lunn <andrew@lunn.ch> > > > > > > I thought we had issues with the 88E6390 where the PCS does not > > > update the MAC with its results. Isn't this going to break the > > > 6390? Andrew? > > > > > > > Russell, I tested this patch on Turris MOX with 6390 on port 9 (cpu > > port) which is configured in devicetree as 2500base-x, in-band-status, > > and it works... > > > > Or will this break on user ports? > > User ports is what needs testing, ideally with an SFP. > > There used to be explicit code which when the SERDES reported link up, > the MAC was configured in software with the correct speed etc. With > the move to pcs APIs, it is less obvious how this works now, does it > still software configure the MAC, or do we have the right magic so > that the hardware updates itself.
It's still there. The speed/duplex etc are read from the serdes PHY via mv88e6390_serdes_pcs_get_state(). When the link comes up, we pass the negotiated link parameters read from there to the link_up() functions. For ports where mv88e6xxx_port_ppu_updates() returns false (no external PHY) we update the port's speed and duplex setting and (currently, before this patch) force the link up.
That was the behaviour before I converted the code, the one that you referred to. I had assumed the code was correct, and _none_ of the speed, duplex, nor link state was propagated from the serdes PCS to the port on the 88E6390 - hence why the code you refer to existed.
-- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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