On 8/13/19 2:25 PM, Heiner Kallweit wrote:
> In cases like a fixed phy that is never attached to a net_device we
> may want to bind the genphy driver at probe time. Setting a PHY ID of
> 0xffffffff to bind the genphy driver would fail due to a check in
> get_phy_device(). Therefore let's change the PHY ID the genphy driver
> binds to to 0xfffffffe. This still shouldn't match any real PHY,
> and it will pass the check in get_phy_devcie().
>
> Signed-off-by: Heiner Kallweit <hkallwe...@gmail.com>
> ---
> drivers/net/phy/phy_device.c | 3 +--
> include/linux/phy.h | 4 ++++
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 163295dbc..54f80af31 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -2388,8 +2388,7 @@ void phy_drivers_unregister(struct phy_driver *drv, int
> n)
> EXPORT_SYMBOL(phy_drivers_unregister);
>
> static struct phy_driver genphy_driver = {
> - .phy_id = 0xffffffff,
> - .phy_id_mask = 0xffffffff,
> + PHY_ID_MATCH_EXACT(GENPHY_ID),
> .name = "Generic PHY",
> .soft_reset = genphy_no_soft_reset,
> .get_features = genphy_read_abilities,
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 5ac7d2137..3b07bce78 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -37,6 +37,10 @@
> #define PHY_1000BT_FEATURES (SUPPORTED_1000baseT_Half | \
> SUPPORTED_1000baseT_Full)
>
> +#define GENPHY_ID_HIGH 0xffffU
> +#define GENPHY_ID_LOW 0xfffeU
> +#define GENPHY_ID ((GENPHY_ID_HIGH << 16) | GENPHY_ID_LOW)
This is a possible user ABI change here, if there is anything that
relies on reading 0xffff_ffff as a valid PHY OUI, you would be breaking
it. We might as well try to assign ourselves a specific PHY OUI, very
much like the Linux USB hubs show up with a Linux Foundation vendor ID.
--
Florian
