[PATCH 5.15 148/177] net: ethernet: stmmac: fix write to sgmii_adapter_base

[Greg Kroah-Hartman]

From: Dinh Nguyen <dinguyen@xxxxxxxxxx>

commit 5fd1fe4807f91ea0cca043114d929faa11bd4190 upstream.

I made a mistake with the commit a6aaa0032424 ("net: ethernet: stmmac:
fix altr_tse_pcs function when using a fixed-link"). I should have
tested against both scenario of having a SGMII interface and one
without.

Without the SGMII PCS TSE adpater, the sgmii_adapter_base address is
NULL, thus a write to this address will fail.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: a6aaa0032424 ("net: ethernet: stmmac: fix altr_tse_pcs function when using a fixed-link")
Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220420152345.27415-1-dinguyen@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
@@ -65,8 +65,9 @@ static void socfpga_dwmac_fix_mac_speed(
 	struct phy_device *phy_dev = ndev->phydev;
 	u32 val;
 
-	writew(SGMII_ADAPTER_DISABLE,
-	       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
+	if (sgmii_adapter_base)
+		writew(SGMII_ADAPTER_DISABLE,
+		       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
 
 	if (splitter_base) {
 		val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
@@ -88,10 +89,11 @@ static void socfpga_dwmac_fix_mac_speed(
 		writel(val, splitter_base + EMAC_SPLITTER_CTRL_REG);
 	}
 
-	writew(SGMII_ADAPTER_ENABLE,
-	       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
-	if (phy_dev)
+	if (phy_dev && sgmii_adapter_base) {
+		writew(SGMII_ADAPTER_ENABLE,
+		       sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
 		tse_pcs_fix_mac_speed(&dwmac->pcs, phy_dev, speed);
+	}
 }
 
 static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *dev)