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net: mdio-mux: fix C45 access returning -EIO after API change

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The mii_bus API conversion to read_c45() and write_c45() did not cover
the mdio-mux driver before read() and write() were made C22-only.

This broke arch/arm64/boot/dts/freescale/fsl-ls1028a-qds-13bb.dtso.
The -EOPNOTSUPP from mdiobus_c45_read() is transformed by
get_phy_c45_devs_in_pkg() into -EIO, is further propagated to
of_mdiobus_register() and this makes the mdio-mux driver fail to probe
the entire child buses, not just the PHYs that cause access errors.

Fix the regression by introducing special c45 read and write accessors
to mdio-mux which forward the operation to the parent MDIO bus.

Fixes: db1a63aed8 ("net: phy: Remove fallback to old C45 method")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20231017143144.3212657-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean 2023-10-17 17:31:44 +03:00 committed by Jakub Kicinski
parent f921a4a5bf
commit 1f9f2143f2
1 changed files with 47 additions and 0 deletions
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47
drivers/net/mdio/mdio-mux.c
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@ -55,6 +55,27 @@ out:
return r;
}
static int mdio_mux_read_c45(struct mii_bus *bus, int phy_id, int dev_addr,
int regnum)
{
struct mdio_mux_child_bus *cb = bus->priv;
struct mdio_mux_parent_bus *pb = cb->parent;
int r;
mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
if (r)
goto out;
pb->current_child = cb->bus_number;
r = pb->mii_bus->read_c45(pb->mii_bus, phy_id, dev_addr, regnum);
out:
mutex_unlock(&pb->mii_bus->mdio_lock);
return r;
}
/*
* The parent bus' lock is used to order access to the switch_fn.
*/
@ -80,6 +101,28 @@ out:
return r;
}
static int mdio_mux_write_c45(struct mii_bus *bus, int phy_id, int dev_addr,
int regnum, u16 val)
{
struct mdio_mux_child_bus *cb = bus->priv;
struct mdio_mux_parent_bus *pb = cb->parent;
int r;
mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
if (r)
goto out;
pb->current_child = cb->bus_number;
r = pb->mii_bus->write_c45(pb->mii_bus, phy_id, dev_addr, regnum, val);
out:
mutex_unlock(&pb->mii_bus->mdio_lock);
return r;
}
static int parent_count;
static void mdio_mux_uninit_children(struct mdio_mux_parent_bus *pb)
@ -173,6 +216,10 @@ int mdio_mux_init(struct device *dev,
cb->mii_bus->parent = dev;
cb->mii_bus->read = mdio_mux_read;
cb->mii_bus->write = mdio_mux_write;
if (parent_bus->read_c45)
cb->mii_bus->read_c45 = mdio_mux_read_c45;
if (parent_bus->write_c45)
cb->mii_bus->write_c45 = mdio_mux_write_c45;
r = of_mdiobus_register(cb->mii_bus, child_bus_node);
if (r) {
mdiobus_free(cb->mii_bus);