Re: [PATCH] net: phy: marvell: fix detection of PHY on Topaz switches

From: Andrew Lunn
Date: Mon Apr 12 2021 - 09:15:14 EST


> +static u16 mv88e6xxx_physid_for_family(enum mv88e6xxx_family family);
> +

No forward declaration please. Move the code around. It is often best
to do that in a patch which just moves code, no other changes. It
makes it easier to review.

> static int mv88e6xxx_mdio_read(struct mii_bus *bus, int phy, int reg)
> {
> struct mv88e6xxx_mdio_bus *mdio_bus = bus->priv;
> @@ -3040,24 +3042,9 @@ static int mv88e6xxx_mdio_read(struct mii_bus *bus, int phy, int reg)
> err = chip->info->ops->phy_read(chip, bus, phy, reg, &val);
> mv88e6xxx_reg_unlock(chip);
>
> - if (reg == MII_PHYSID2) {
> - /* Some internal PHYs don't have a model number. */
> - 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;
> - }
> + /* Some internal PHYs don't have a model number. */
> + if (reg == MII_PHYSID2 && !(val & 0x3f0))
> + val |= mv88e6xxx_physid_for_family(chip->info->family);
>
> return err ? err : val;
> }
> @@ -5244,6 +5231,39 @@ static const struct mv88e6xxx_info *mv88e6xxx_lookup_info(unsigned int prod_num)
> return NULL;
> }
>
> +/* This table contains representative model for every family */
> +static const enum mv88e6xxx_model family_model_table[] = {
> + [MV88E6XXX_FAMILY_6095] = MV88E6095,
> + [MV88E6XXX_FAMILY_6097] = MV88E6097,
> + [MV88E6XXX_FAMILY_6185] = MV88E6185,
> + [MV88E6XXX_FAMILY_6250] = MV88E6250,
> + [MV88E6XXX_FAMILY_6320] = MV88E6320,
> + [MV88E6XXX_FAMILY_6341] = MV88E6341,
> + [MV88E6XXX_FAMILY_6351] = MV88E6351,
> + [MV88E6XXX_FAMILY_6352] = MV88E6352,
> + [MV88E6XXX_FAMILY_6390] = MV88E6390,
> +};

This table is wrong. MV88E6390 does not equal
MV88E6XXX_PORT_SWITCH_ID_PROD_6390. MV88E6XXX_PORT_SWITCH_ID_PROD_6390
was chosen because it is already an MDIO device ID, in register 2 and
3. It probably will never clash with a real Marvell PHY ID. MV88E6390
is just a small integer, and there is a danger it will clash with a
real PHY.

> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -3021,9 +3021,34 @@ static struct phy_driver marvell_drivers[] = {
> .get_stats = marvell_get_stats,
> },
> {
> - .phy_id = MARVELL_PHY_ID_88E6390,
> + .phy_id = MARVELL_PHY_ID_88E6341_FAMILY,
> .phy_id_mask = MARVELL_PHY_ID_MASK,
> - .name = "Marvell 88E6390",
> + .name = "Marvell 88E6341 Family",

You cannot just replace the MARVELL_PHY_ID_88E6390. That will break
the 6390! You need to add the new PHY for the 88E6341.

Andrew