net: xilinx: axienet: Fix dangling multicast addresses

If a multicast address is removed but there are still some multicast
addresses, that address would remain programmed into the frame filter.
Fix this by explicitly setting the enable bit for each filter.

Fixes: 8a3b7a2 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240822154059.1066595-3-sean.anderson@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Sean Anderson

drivers/net/ethernet/xilinx/xilinx_axienet.h

@@ -170,6 +170,7 @@
 #define XAE_UAW0_OFFSET		0x00000700 /* Unicast address word 0 */
 #define XAE_UAW1_OFFSET		0x00000704 /* Unicast address word 1 */
 #define XAE_FMI_OFFSET		0x00000708 /* Frame Filter Control */
+#define XAE_FFE_OFFSET		0x0000070C /* Frame Filter Enable */
 #define XAE_AF0_OFFSET		0x00000710 /* Address Filter 0 */
 #define XAE_AF1_OFFSET		0x00000714 /* Address Filter 1 */
 

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -432,7 +432,7 @@ static int netdev_set_mac_address(struct net_device *ndev, void *p)
  */
 static void axienet_set_multicast_list(struct net_device *ndev)
 {
-	int i;
+	int i = 0;
 	u32 reg, af0reg, af1reg;
 	struct axienet_local *lp = netdev_priv(ndev);
 
@@ -454,7 +454,6 @@ static void axienet_set_multicast_list(struct net_device *ndev)
 		reg &= ~XAE_FMI_PM_MASK;
 		axienet_iow(lp, XAE_FMI_OFFSET, reg);
 
-		i = 0;
 		netdev_for_each_mc_addr(ha, ndev) {
 			if (i >= XAE_MULTICAST_CAM_TABLE_NUM)
 				break;
@@ -473,25 +472,23 @@ static void axienet_set_multicast_list(struct net_device *ndev)
 			axienet_iow(lp, XAE_FMI_OFFSET, reg);
 			axienet_iow(lp, XAE_AF0_OFFSET, af0reg);
 			axienet_iow(lp, XAE_AF1_OFFSET, af1reg);
+			axienet_iow(lp, XAE_FFE_OFFSET, 1);
 			i++;
 		}
 	} else {
 		reg = axienet_ior(lp, XAE_FMI_OFFSET);
 		reg &= ~XAE_FMI_PM_MASK;
 
 		axienet_iow(lp, XAE_FMI_OFFSET, reg);
-
-		for (i = 0; i < XAE_MULTICAST_CAM_TABLE_NUM; i++) {
-			reg = axienet_ior(lp, XAE_FMI_OFFSET) & 0xFFFFFF00;
-			reg |= i;
-
-			axienet_iow(lp, XAE_FMI_OFFSET, reg);
-			axienet_iow(lp, XAE_AF0_OFFSET, 0);
-			axienet_iow(lp, XAE_AF1_OFFSET, 0);
-		}
-
 		dev_info(&ndev->dev, "Promiscuous mode disabled.\n");
 	}
+
+	for (; i < XAE_MULTICAST_CAM_TABLE_NUM; i++) {
+		reg = axienet_ior(lp, XAE_FMI_OFFSET) & 0xFFFFFF00;
+		reg |= i;
+		axienet_iow(lp, XAE_FMI_OFFSET, reg);
+		axienet_iow(lp, XAE_FFE_OFFSET, 0);
+	}
 }
 
 /**