staging: et131x: Fix errors caused by phydev->addr accesses before initialisation

Fix two reported bugs, caused by et131x_adapter->phydev->addr being accessed
before it is initialised, by:

- letting et131x_mii_write() take a phydev address, instead of using the one
  stored in adapter by default. This is so et131x_mdio_write() can use it's own
  addr value.
- removing implementation of et131x_mdio_reset(), as it's not needed.
- moving a call to et131x_disable_phy_coma() in et131x_pci_setup(), which uses
  phydev->addr, until after the mdiobus has been registered.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=80751
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77121
Cc: stable@vger.kernel.org
Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/et131x/et131x.c

@@ -1421,22 +1421,16 @@ static int et131x_mii_read(struct et131x_adapter *adapter, u8 reg, u16 *value)
  * @reg: the register to read
  * @value: 16-bit value to write
  */
-static int et131x_mii_write(struct et131x_adapter *adapter, u8 reg, u16 value)
+static int et131x_mii_write(struct et131x_adapter *adapter, u8 addr, u8 reg,
+			    u16 value)
 {
 	struct mac_regs __iomem *mac = &adapter->regs->mac;
-	struct phy_device *phydev = adapter->phydev;
 	int status = 0;
-	u8 addr;
 	u32 delay = 0;
 	u32 mii_addr;
 	u32 mii_cmd;
 	u32 mii_indicator;
 
-	if (!phydev)
-		return -EIO;
-
-	addr = phydev->addr;
-
 	/* Save a local copy of the registers we are dealing with so we can
 	 * set them back
 	 */
@@ -1631,17 +1625,7 @@ static int et131x_mdio_write(struct mii_bus *bus, int phy_addr,
 	struct net_device *netdev = bus->priv;
 	struct et131x_adapter *adapter = netdev_priv(netdev);
 
-	return et131x_mii_write(adapter, reg, value);
-}
-
-static int et131x_mdio_reset(struct mii_bus *bus)
-{
-	struct net_device *netdev = bus->priv;
-	struct et131x_adapter *adapter = netdev_priv(netdev);
-
-	et131x_mii_write(adapter, MII_BMCR, BMCR_RESET);
-
-	return 0;
+	return et131x_mii_write(adapter, phy_addr, reg, value);
 }
 
 /*	et1310_phy_power_switch	-	PHY power control
@@ -1656,18 +1640,20 @@ static int et131x_mdio_reset(struct mii_bus *bus)
 static void et1310_phy_power_switch(struct et131x_adapter *adapter, bool down)
 {
 	u16 data;
+	struct  phy_device *phydev = adapter->phydev;
 
 	et131x_mii_read(adapter, MII_BMCR, &data);
 	data &= ~BMCR_PDOWN;
 	if (down)
 		data |= BMCR_PDOWN;
-	et131x_mii_write(adapter, MII_BMCR, data);
+	et131x_mii_write(adapter, phydev->addr, MII_BMCR, data);
 }
 
 /* et131x_xcvr_init - Init the phy if we are setting it into force mode */
 static void et131x_xcvr_init(struct et131x_adapter *adapter)
 {
 	u16 lcr2;
+	struct  phy_device *phydev = adapter->phydev;
 
 	/* Set the LED behavior such that LED 1 indicates speed (off =
 	 * 10Mbits, blink = 100Mbits, on = 1000Mbits) and LED 2 indicates
@@ -1688,7 +1674,7 @@ static void et131x_xcvr_init(struct et131x_adapter *adapter)
 		else
 			lcr2 |= (LED_VAL_LINKON << LED_TXRX_SHIFT);
 
-		et131x_mii_write(adapter, PHY_LED_2, lcr2);
+		et131x_mii_write(adapter, phydev->addr, PHY_LED_2, lcr2);
 	}
 }
 
@@ -3643,14 +3629,14 @@ static void et131x_adjust_link(struct net_device *netdev)
 
 			et131x_mii_read(adapter, PHY_MPHY_CONTROL_REG,
 					 &register18);
-			et131x_mii_write(adapter, PHY_MPHY_CONTROL_REG,
-					 register18 | 0x4);
-			et131x_mii_write(adapter, PHY_INDEX_REG,
+			et131x_mii_write(adapter, phydev->addr,
+					 PHY_MPHY_CONTROL_REG, register18 | 0x4);
+			et131x_mii_write(adapter, phydev->addr, PHY_INDEX_REG,
 					 register18 | 0x8402);
-			et131x_mii_write(adapter, PHY_DATA_REG,
+			et131x_mii_write(adapter, phydev->addr, PHY_DATA_REG,
 					 register18 | 511);
-			et131x_mii_write(adapter, PHY_MPHY_CONTROL_REG,
-					 register18);
+			et131x_mii_write(adapter, phydev->addr,
+					 PHY_MPHY_CONTROL_REG, register18);
 		}
 
 		et1310_config_flow_control(adapter);
@@ -3662,7 +3648,8 @@ static void et131x_adjust_link(struct net_device *netdev)
 			et131x_mii_read(adapter, PHY_CONFIG, &reg);
 			reg &= ~ET_PHY_CONFIG_TX_FIFO_DEPTH;
 			reg |= ET_PHY_CONFIG_FIFO_DEPTH_32;
-			et131x_mii_write(adapter, PHY_CONFIG, reg);
+			et131x_mii_write(adapter, phydev->addr, PHY_CONFIG,
+					 reg);
 		}
 
 		et131x_set_rx_dma_timer(adapter);
@@ -3675,14 +3662,14 @@ static void et131x_adjust_link(struct net_device *netdev)
 
 			et131x_mii_read(adapter, PHY_MPHY_CONTROL_REG,
 					 &register18);
-			et131x_mii_write(adapter, PHY_MPHY_CONTROL_REG,
-					 register18 | 0x4);
-			et131x_mii_write(adapter, PHY_INDEX_REG,
-					 register18 | 0x8402);
-			et131x_mii_write(adapter, PHY_DATA_REG,
-					 register18 | 511);
-			et131x_mii_write(adapter, PHY_MPHY_CONTROL_REG,
-					 register18);
+			et131x_mii_write(adapter, phydev->addr,
+					PHY_MPHY_CONTROL_REG, register18 | 0x4);
+			et131x_mii_write(adapter, phydev->addr,
+					PHY_INDEX_REG, register18 | 0x8402);
+			et131x_mii_write(adapter, phydev->addr,
+					PHY_DATA_REG, register18 | 511);
+			et131x_mii_write(adapter, phydev->addr,
+					PHY_MPHY_CONTROL_REG, register18);
 		}
 
 		/* Free the packets being actively sent & stopped */
@@ -4644,10 +4631,6 @@ static int et131x_pci_setup(struct pci_dev *pdev,
 	/* Copy address into the net_device struct */
 	memcpy(netdev->dev_addr, adapter->addr, ETH_ALEN);
 
-	/* Init variable for counting how long we do not have link status */
-	adapter->boot_coma = 0;
-	et1310_disable_phy_coma(adapter);
-
 	rc = -ENOMEM;
 
 	/* Setup the mii_bus struct */
@@ -4663,7 +4646,6 @@ static int et131x_pci_setup(struct pci_dev *pdev,
 	adapter->mii_bus->priv = netdev;
 	adapter->mii_bus->read = et131x_mdio_read;
 	adapter->mii_bus->write = et131x_mdio_write;
-	adapter->mii_bus->reset = et131x_mdio_reset;
 	adapter->mii_bus->irq = kmalloc_array(PHY_MAX_ADDR, sizeof(int),
 					      GFP_KERNEL);
 	if (!adapter->mii_bus->irq)
@@ -4687,6 +4669,10 @@ static int et131x_pci_setup(struct pci_dev *pdev,
 	/* Setup et1310 as per the documentation */
 	et131x_adapter_setup(adapter);
 
+	/* Init variable for counting how long we do not have link status */
+	adapter->boot_coma = 0;
+	et1310_disable_phy_coma(adapter);
+
 	/* We can enable interrupts now
 	 *
 	 *  NOTE - Because registration of interrupt handler is done in the