netdev - [PATCH RFC] net: mdio_bus: make check in mdiobus_prevent_c45

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Date: Tue, 2 Jan 2024 15:38:05 +0100
From: Heiner Kallweit <hkallweit1@...il.com>
To: Russell King <rmk+kernel@...linux.org.uk>, Andrew Lunn <andrew@...n.ch>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH RFC] net: mdio_bus: make check in mdiobus_prevent_c45_scan
 more granular

Matching on OUI level is a quite big hammer. So let's make matching
more granular.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
This is what I'm thinking of. Maybe the problem of misbehaving
on c45 access affects certain groups of PHY's only.
Then we don't have to blacklist all PHY's from this vendor.
What do you think?
---
 drivers/net/phy/mdio_bus.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 6cf73c156..848d5d2d6 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -621,19 +621,27 @@ static int mdiobus_scan_bus_c45(struct mii_bus *bus)
  */
 static bool mdiobus_prevent_c45_scan(struct mii_bus *bus)
 {
-	int i;
+	const struct {
+		u32 phy_id;
+		u32 phy_id_mask;
+	} id_list[] = {
+		{ MICREL_OUI << 10, GENMASK(31, 10) },
+	};
+	int i, j;
 
 	for (i = 0; i < PHY_MAX_ADDR; i++) {
 		struct phy_device *phydev;
-		u32 oui;
 
 		phydev = mdiobus_get_phy(bus, i);
 		if (!phydev)
 			continue;
-		oui = phydev->phy_id >> 10;
 
-		if (oui == MICREL_OUI)
-			return true;
+		for (j = 0; j < ARRAY_SIZE(id_list); j++) {
+			u32 mask = id_list[j].phy_id_mask;
+
+			if ((phydev->phy_id & mask) == (id_list[j].phy_id & mask))
+				return true;
+		}
 	}
 	return false;
 }
-- 
2.43.0