net: phy: generate PHY mdio modalias

The modalias string provided in the uevent sysfs file does not conform
to the format used in PHY driver modules. One of the reasons is that
udev loading of PHY driver modules has not been an expected use case.

This patch changes the MODALIAS entry for only PHY devices from:
        MODALIAS=of:Nethernet-phyT(null)
to:
        MODALIAS=mdio:00000000001000100001010100010011

Other MDIO devices (such as DSA) remain as before.

However, having udev automatically load the module has the advantage
of making use of existing functionality to have the module loaded
before the device is bound to the driver, thus taking advantage of
multithreaded boot systems, potentially decreasing the boot time.

However, this patch will not solve any issues with the driver module
not being loaded prior to the network device needing to use the PHY.
This is something that is completely out of control of any patch to
change the uevent mechanism.

Reported-by: Yinbo Zhu <zhuyinbo@loongson.cn>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

3 files changed, 24 insertions, 0 deletions

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index e051a0d5e0df..af74f46a5f21 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -1017,8 +1017,16 @@ static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 
 static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
+	struct mdio_device *mdio = to_mdio_device(dev);
 	int rc;
 
+	/* Use the device-specific uevent if specified */
+	if (mdio->bus_uevent) {
+		rc = mdio->bus_uevent(mdio, env);
+		if (rc != -ENODEV)
+			return rc;
+	}
+
 	/* Some devices have extra OF data and an OF-style MODALIAS */
 	rc = of_device_uevent_modalias(dev, env);
 	if (rc != -ENODEV)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index f6c27c23dde0..d8a6146d971a 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -563,6 +563,19 @@ static int phy_request_driver_module(struct phy_device *dev, u32 phy_id)
 	return 0;
 }
 
+static int phy_bus_uevent(struct mdio_device *mdiodev,
+			  struct kobj_uevent_env *env)
+{
+	struct phy_device *phydev;
+
+	phydev = container_of(mdiodev, struct phy_device, mdio);
+
+	add_uevent_var(env, "MODALIAS=" MDIO_MODULE_PREFIX MDIO_ID_FMT,
+		       MDIO_ID_ARGS(phydev->phy_id));
+
+	return 0;
+}
+
 struct phy_device *phy_device_create(struct mii_bus *bus, int addr, u32 phy_id,
 				     bool is_c45,
 				     struct phy_c45_device_ids *c45_ids)
@@ -582,6 +595,7 @@ struct phy_device *phy_device_create(struct mii_bus *bus, int addr, u32 phy_id,
 	mdiodev->dev.type = &mdio_bus_phy_type;
 	mdiodev->bus = bus;
 	mdiodev->bus_match = phy_bus_match;
+	mdiodev->bus_uevent = phy_bus_uevent;
 	mdiodev->addr = addr;
 	mdiodev->flags = MDIO_DEVICE_FLAG_PHY;
 	mdiodev->device_free = phy_mdio_device_free;
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index d28a5c1a9260..7b01417a0c6e 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -40,6 +40,8 @@ struct mdio_device {
 	char modalias[MDIO_NAME_SIZE];
 
 	int (*bus_match)(struct device *dev, struct device_driver *drv);
+	int (*bus_uevent)(struct mdio_device *mdiodev,
+			  struct kobj_uevent_env *env);
 	void (*device_free)(struct mdio_device *mdiodev);
 	void (*device_remove)(struct mdio_device *mdiodev);