6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
commit 1f9f2143f24e224a8582a5d54918c43b9121eccc upstream.
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: db1a63aed89c ("net: phy: Remove fallback to old C45 method")
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231017143144.3212657-1-vladimir.oltean@xxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/mdio/mdio-mux.c | 47 +++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c
index a881e3523328..bef4cce71287 100644
--- a/drivers/net/mdio/mdio-mux.c
+++ b/drivers/net/mdio/mdio-mux.c
@@ -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);
--
2.42.0
