netdev - Re: [PATCH net-next] net: dsa: mv88e6xxx: Work around mv886e6161 SERDES missing MII

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Date:   Sun, 11 Nov 2018 11:44:25 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:     Andrew Lunn <andrew@...n.ch>, David Miller <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] net: dsa: mv88e6xxx: Work around mv886e6161
 SERDES missing MII_PHYSID2

Hello!

On 11.11.2018 2:50, Andrew Lunn wrote:

> We already have a workaround for a couple of switches whose internal
> PHYs only have the Marvel OUI, but no model number. We detect such
> PHYs and give them the 6390 ID as the model number. However the
> mv88e6161 has two SERDES interfaces in the same address range as its
> internal PHYs. These suffer from the same problem, the Marvell OUI,
> but no model number. As a result, these SERDES interfaces were getting
> the same PHY ID as the mv88e6390, even though they are not PHYs, and
> the Marvell PHY driver was trying to drive them.
> 
> Add a special case to stop this happen.

    Dtop this from happening, maybe?

> 
> Reported-by: Chris Healy <Chris.Healy@....aero>
> Signed-off-by: Andrew Lunn <andrew@...n.ch>
> ---
>   drivers/net/dsa/mv88e6xxx/chip.c | 21 ++++++++++++++++-----
>   1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index fc0f508879d4..4906a4f39d62 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -2524,11 +2524,22 @@ static int mv88e6xxx_mdio_read(struct mii_bus *bus, int phy, int reg)
>   	mutex_unlock(&chip->reg_lock);
>   
>   	if (reg == MII_PHYSID2) {
> -		/* Some internal PHYS don't have a model number.  Use
> -		 * the mv88e6390 family model number instead.
> -		 */
> -		if (!(val & 0x3f0))
> -			val |= MV88E6XXX_PORT_SWITCH_ID_PROD_6390 >> 4;
> +		/* Some internal PHYS don't have a model number. */

    PHYs (else you're inconsistent with the next comment).

> +		if (chip->info->family != MV88E6XXX_FAMILY_6165)
> +			/* Then there is the 6165 family. It gets is
> +			 * PHYs correct. But it can also have two
> +			 * SERDES interfaces in the PHY address
> +			 * space. And these don't have a model
> +			 * number. But they are not PHYs, so we don't
> +			 * want to give them something a PHY driver
> +			 * will recognise.
> +			 *
> +			 * Use the mv88e6390 family model number
> +			 * instead, for anything which really could be
> +			 * a PHY,
> +			 */
> +			if (!(val & 0x3f0))
> +				val |= MV88E6XXX_PORT_SWITCH_ID_PROD_6390 >> 4;
>   	}
>   
>   	return err ? err : val;

MBR, Sergei