Messages in this thread | | | Date | Tue, 17 Oct 2023 14:31:30 +0100 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH net] net: mdio-mux: fix C45 access returning -EIO after API change |
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On Tue, Oct 17, 2023 at 02:32:22PM +0300, Vladimir Oltean wrote: > 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@nxp.com> > --- > drivers/net/mdio/mdio-mux.c | 45 +++++++++++++++++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c > index a881e3523328..7d322c08c1e9 100644 > --- a/drivers/net/mdio/mdio-mux.c > +++ b/drivers/net/mdio/mdio-mux.c > @@ -55,6 +55,27 @@ static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum) > 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);
What if the parent bus doesn't have read_c45 or write_c45 ?
> @@ -173,6 +216,8 @@ 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; > + cb->mii_bus->read_c45 = mdio_mux_read_c45; > + cb->mii_bus->write_c45 = mdio_mux_write_c45;
Maybe make these conditional on the parent bus implementing the c45 read/write ops?
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