On Wed, Oct 28, 2020 at 11:14:25PM +0100, Marek Behún wrote:
> Instead of configuring the I2C mdiobus when SFP driver is probed,
> configure/destroy the mdiobus when SFP transceiver is plugged/unplugged.
>
> This way we can tell the mdio-i2c code which protocol to use for each
> SFP transceiver.
>
> Signed-off-by: Marek Behún <ka...@kernel.org>
> Cc: Andrew Lunn <and...@lunn.ch>
> Cc: Russell King <rmk+ker...@armlinux.org.uk>
> ---
> drivers/net/phy/sfp.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index b1f9fc3a5584..a392d5fc6ab4 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -399,9 +399,6 @@ static int sfp_i2c_write(struct sfp *sfp, bool a2, u8
> dev_addr, void *buf,
>
> static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
> {
> - struct mii_bus *i2c_mii;
> - int ret;
> -
> if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
> return -EINVAL;
>
> @@ -409,7 +406,15 @@ static int sfp_i2c_configure(struct sfp *sfp, struct
> i2c_adapter *i2c)
> sfp->read = sfp_i2c_read;
> sfp->write = sfp_i2c_write;
>
> - i2c_mii = mdio_i2c_alloc(sfp->dev, i2c, MDIO_I2C_DEFAULT);
> + return 0;
> +}
> +
> +static int sfp_i2c_mdiobus_configure(struct sfp *sfp, enum mdio_i2c_type
> type)
> +{
> + struct mii_bus *i2c_mii;
> + int ret;
> +
> + i2c_mii = mdio_i2c_alloc(sfp->dev, sfp->i2c, type);
> if (IS_ERR(i2c_mii))
> return PTR_ERR(i2c_mii);
>
> @@ -427,6 +432,12 @@ static int sfp_i2c_configure(struct sfp *sfp, struct
> i2c_adapter *i2c)
> return 0;
> }
>
> +static void sfp_i2c_mdiobus_destroy(struct sfp *sfp)
> +{
> + mdiobus_unregister(sfp->i2c_mii);
> + sfp->i2c_mii = NULL;
> +}
> +
> /* Interface */
> static int sfp_read(struct sfp *sfp, bool a2, u8 addr, void *buf, size_t len)
> {
> @@ -1768,6 +1779,11 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool
> report)
> else
> sfp->module_t_start_up = T_START_UP;
>
> + /* Configure mdiobus */
> + ret = sfp_i2c_mdiobus_configure(sfp, MDIO_I2C_DEFAULT);
> + if (ret < 0)
> + return ret;
> +
return sfp_i2c_mdiobus_configure(sfp, MDIO_I2C_DEFAULT);
would be a simpler way to write this. However, I suggest handling this
elsewhere due to the point below.
> @@ -1778,6 +1794,8 @@ static void sfp_sm_mod_remove(struct sfp *sfp)
>
> sfp_hwmon_remove(sfp);
>
> + sfp_i2c_mdiobus_destroy(sfp);
> +
This doesn't seem like the right place to handle this. This is called
from the module state machine (sfp_sm_module()) which is run before the
main state machine (sfp_sm_main()). The PHY is unregistered in the main
state machine, which means you're destroying the MII bus before the
PHY.
I guess what saves us from crashing is the refcounting, but this
doesn't seem to me to be particularly good.
Maybe create the MII bus after the "init_done" label, and destroy it
after we've called sfp_sm_phy_detach() ?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
