linux-kernel - Re: [PATCH net-next] net: dsa: mv88e6xxx: Fix validation of built-in PHYs on 6095/6097

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Date:   Sun, 13 Feb 2022 12:58:39 +0000
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Tobias Waldekranz <tobias@...dekranz.com>
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        Marek Behún <kabel@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] net: dsa: mv88e6xxx: Fix validation of built-in
 PHYs on 6095/6097

Hi,

Thanks for spotting this. Some comments below.

On Sun, Feb 13, 2022 at 01:37:01AM +0100, Tobias Waldekranz wrote:
> +static void mv88e6095_phylink_get_caps(struct mv88e6xxx_chip *chip, int port,
> +				       struct phylink_config *config)
> +{
> +	u8 cmode = chip->ports[port].cmode;
> +
> +	config->mac_capabilities = MAC_SYM_PAUSE | MAC_10 | MAC_100;
> +
> +	if (mv88e6xxx_phy_is_internal(chip->ds, port)) {
> +		if (cmode == MV88E6185_PORT_STS_CMODE_PHY)
> +			__set_bit(PHY_INTERFACE_MODE_MII,
> +				  config->supported_interfaces);

Hmm. First, note that with mv88e6xxx_get_caps(), you'll end up with both
MII and GMII here. GMII is necessary as that's the phylib default if no
one specifies anything different in the firmware description. I assume
you've noticed a problem because you specify MII for the internal ports
in firmware?

I'm wondering what the point of checking the cmode here is - if the port
is internal, won't this switch always have cmode == PHY?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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