[PATCH net-next v4 2/2] ixgbe: use mii_bus to handle MII related ioctls

[Steve Douthit <stephend@silicom-usa.com>]

Use the mii_bus callbacks to address the entire clause 22/45 address
space.  Enables userspace to poke switch registers instead of a single
PHY address.

The ixgbe firmware may be polling PHYs in a way that is not protected by
the mii_bus lock.  This isn't new behavior, but as Andrew Lunn pointed
out there are more addresses available for conflicts.

Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index b7907674c565..caa64afdedfb 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -8790,6 +8790,15 @@ ixgbe_mdio_read(struct net_device *netdev, int prtad, int devad, u16 addr)
 	u16 value;
 	int rc;
 
+	if (adapter->mii_bus) {
+		int regnum = addr;
+
+		if (devad != MDIO_DEVAD_NONE)
+			regnum |= (devad << 16) | MII_ADDR_C45;
+
+		return mdiobus_read(adapter->mii_bus, prtad, regnum);
+	}
+
 	if (prtad != hw->phy.mdio.prtad)
 		return -EINVAL;
 	rc = hw->phy.ops.read_reg(hw, addr, devad, &value);
@@ -8804,6 +8813,15 @@ static int ixgbe_mdio_write(struct net_device *netdev, int prtad, int devad,
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 	struct ixgbe_hw *hw = &adapter->hw;
 
+	if (adapter->mii_bus) {
+		int regnum = addr;
+
+		if (devad != MDIO_DEVAD_NONE)
+			regnum |= (devad << 16) | MII_ADDR_C45;
+
+		return mdiobus_write(adapter->mii_bus, prtad, regnum, value);
+	}
+
 	if (prtad != hw->phy.mdio.prtad)
 		return -EINVAL;
 	return hw->phy.ops.write_reg(hw, addr, devad, value);
-- 
2.17.2