Merge branch 'net-xilinx-axienet-multicast-fixes-and-improvements'

Sean Anderson says:

====================
net: xilinx: axienet: Multicast fixes and improvements

This series has a few small patches improving the handling of multicast
addresses. In particular, it makes the driver a whole lot less spammy,
and adjusts things so we aren't in promiscuous mode when we have more
than four multicast addresses (a common occurance on modern systems).

As the hardware has a 4-entry CAM, the ideal method would be to "pack"
multiple addresses into one CAM entry. Something like:

entry.address = address[0] | address[1];
entry.mask = ~(address[0] ^ address[1]);

Which would make the entry match both addresses (along with some others
that would need to be filtered in software).

Mapping addresses to entries in an efficient way is a bit tricky. If
anyone knows of an in-tree example of something like this, I'd be glad
to hear about it.
====================

Link: https://patch.msgid.link/20240822154059.1066595-1-sean.anderson@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 22 insertions, 21 deletions

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index 5a7d6b872f5d..c301dd2ee083 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -175,6 +175,8 @@
 #define XAE_FFE_OFFSET		0x0000070C /* Frame Filter Enable */
 #define XAE_AF0_OFFSET		0x00000710 /* Address Filter 0 */
 #define XAE_AF1_OFFSET		0x00000714 /* Address Filter 1 */
+#define XAE_AM0_OFFSET		0x00000750 /* Frame Filter Mask Value Bytes 3-0 */
+#define XAE_AM1_OFFSET		0x00000754 /* Frame Filter Mask Value Bytes 7-4 */
 
 #define XAE_TX_VLAN_DATA_OFFSET 0x00004000 /* TX VLAN data table address */
 #define XAE_RX_VLAN_DATA_OFFSET 0x00008000 /* RX VLAN data table address */
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 88ff82c52d0c..fe6a0e2e463f 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -437,24 +437,27 @@ static void axienet_set_multicast_list(struct net_device *ndev)
 	u32 reg, af0reg, af1reg;
 	struct axienet_local *lp = netdev_priv(ndev);
 
-	if (ndev->flags & (IFF_ALLMULTI | IFF_PROMISC) ||
-	    netdev_mc_count(ndev) > XAE_MULTICAST_CAM_TABLE_NUM) {
-		/* We must make the kernel realize we had to move into
-		 * promiscuous mode. If it was a promiscuous mode request
-		 * the flag is already set. If not we set it.
-		 */
-		ndev->flags |= IFF_PROMISC;
-		reg = axienet_ior(lp, XAE_FMI_OFFSET);
+	reg = axienet_ior(lp, XAE_FMI_OFFSET);
+	reg &= ~XAE_FMI_PM_MASK;
+	if (ndev->flags & IFF_PROMISC)
 		reg |= XAE_FMI_PM_MASK;
+	else
+		reg &= ~XAE_FMI_PM_MASK;
+	axienet_iow(lp, XAE_FMI_OFFSET, reg);
+
+	if (ndev->flags & IFF_ALLMULTI ||
+	    netdev_mc_count(ndev) > XAE_MULTICAST_CAM_TABLE_NUM) {
+		reg &= 0xFFFFFF00;
 		axienet_iow(lp, XAE_FMI_OFFSET, reg);
-		dev_info(&ndev->dev, "Promiscuous mode enabled.\n");
+		axienet_iow(lp, XAE_AF0_OFFSET, 1); /* Multicast bit */
+		axienet_iow(lp, XAE_AF1_OFFSET, 0);
+		axienet_iow(lp, XAE_AM0_OFFSET, 1); /* ditto */
+		axienet_iow(lp, XAE_AM1_OFFSET, 0);
+		axienet_iow(lp, XAE_FFE_OFFSET, 1);
+		i = 1;
 	} else if (!netdev_mc_empty(ndev)) {
 		struct netdev_hw_addr *ha;
 
-		reg = axienet_ior(lp, XAE_FMI_OFFSET);
-		reg &= ~XAE_FMI_PM_MASK;
-		axienet_iow(lp, XAE_FMI_OFFSET, reg);
-
 		netdev_for_each_mc_addr(ha, ndev) {
 			if (i >= XAE_MULTICAST_CAM_TABLE_NUM)
 				break;
@@ -467,25 +470,21 @@ static void axienet_set_multicast_list(struct net_device *ndev)
 			af1reg = (ha->addr[4]);
 			af1reg |= (ha->addr[5] << 8);
 
-			reg = axienet_ior(lp, XAE_FMI_OFFSET) & 0xFFFFFF00;
+			reg &= 0xFFFFFF00;
 			reg |= i;
 
 			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_AM0_OFFSET, 0xffffffff);
+			axienet_iow(lp, XAE_AM1_OFFSET, 0x0000ffff);
 			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);
-		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 &= 0xFFFFFF00;
 		reg |= i;
 		axienet_iow(lp, XAE_FMI_OFFSET, reg);
 		axienet_iow(lp, XAE_FFE_OFFSET, 0);