net: ethernet: stmmac: fix altr_tse_pcs function when using a fixed-link

When using a fixed-link, the altr_tse_pcs driver crashes
due to null-pointer dereference as no phy_device is provided to
tse_pcs_fix_mac_speed function. Fix this by adding a check for
phy_dev before calling the tse_pcs_fix_mac_speed() function.

Also clean up the tse_pcs_fix_mac_speed function a bit. There is
no need to check for splitter_base and sgmii_adapter_base
because the driver will fail if these 2 variables are not
derived from the device tree.

Fixes: fb3bbdb8 ("net: ethernet: Add TSE PCS support to dwmac-socfpga")
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/altr_tse_pcs.c

@@ -57,10 +57,6 @@
 #define TSE_PCS_USE_SGMII_ENA				BIT(0)
 #define TSE_PCS_IF_USE_SGMII				0x03
 
-#define SGMII_ADAPTER_CTRL_REG				0x00
-#define SGMII_ADAPTER_DISABLE				0x0001
-#define SGMII_ADAPTER_ENABLE				0x0000
-
 #define AUTONEGO_LINK_TIMER				20
 
 static int tse_pcs_reset(void __iomem *base, struct tse_pcs *pcs)
@@ -202,12 +198,8 @@ void tse_pcs_fix_mac_speed(struct tse_pcs *pcs, struct phy_device *phy_dev,
 			   unsigned int speed)
 {
 	void __iomem *tse_pcs_base = pcs->tse_pcs_base;
-	void __iomem *sgmii_adapter_base = pcs->sgmii_adapter_base;
 	u32 val;
 
-	writew(SGMII_ADAPTER_ENABLE,
-	       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
-
 	pcs->autoneg = phy_dev->autoneg;
 
 	if (phy_dev->autoneg == AUTONEG_ENABLE) {

drivers/net/ethernet/stmicro/stmmac/altr_tse_pcs.h

@@ -10,6 +10,10 @@
 #include <linux/phy.h>
 #include <linux/timer.h>
 
+#define SGMII_ADAPTER_CTRL_REG		0x00
+#define SGMII_ADAPTER_ENABLE		0x0000
+#define SGMII_ADAPTER_DISABLE		0x0001
+
 struct tse_pcs {
 	struct device *dev;
 	void __iomem *tse_pcs_base;

drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c

@@ -18,9 +18,6 @@
 
 #include "altr_tse_pcs.h"
 
-#define SGMII_ADAPTER_CTRL_REG                          0x00
-#define SGMII_ADAPTER_DISABLE                           0x0001
-
 #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII 0x0
 #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RGMII 0x1
 #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RMII 0x2
@@ -62,16 +59,14 @@ static void socfpga_dwmac_fix_mac_speed(void *priv, unsigned int speed)
 {
 	struct socfpga_dwmac *dwmac = (struct socfpga_dwmac *)priv;
 	void __iomem *splitter_base = dwmac->splitter_base;
-	void __iomem *tse_pcs_base = dwmac->pcs.tse_pcs_base;
 	void __iomem *sgmii_adapter_base = dwmac->pcs.sgmii_adapter_base;
 	struct device *dev = dwmac->dev;
 	struct net_device *ndev = dev_get_drvdata(dev);
 	struct phy_device *phy_dev = ndev->phydev;
 	u32 val;
 
-	if ((tse_pcs_base) && (sgmii_adapter_base))
-		writew(SGMII_ADAPTER_DISABLE,
-		       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
+	writew(SGMII_ADAPTER_DISABLE,
+	       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
 
 	if (splitter_base) {
 		val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
@@ -93,7 +88,9 @@ static void socfpga_dwmac_fix_mac_speed(void *priv, unsigned int speed)
 		writel(val, splitter_base + EMAC_SPLITTER_CTRL_REG);
 	}
 
-	if (tse_pcs_base && sgmii_adapter_base)
+	writew(SGMII_ADAPTER_ENABLE,
+	       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
+	if (phy_dev)
 		tse_pcs_fix_mac_speed(&dwmac->pcs, phy_dev, speed);
 }