1 files changed, 34 insertions, 4 deletions

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 8222c8a6c5ec..7310d19d1f06 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -1021,14 +1021,32 @@ static int ksz9477_port_mirror_add(struct dsa_switch *ds, int port,
 				   bool ingress, struct netlink_ext_ack *extack)
 {
 	struct ksz_device *dev = ds->priv;
+	u8 data;
+	int p;
+
+	/* Limit to one sniffer port
+	 * Check if any of the port is already set for sniffing
+	 * If yes, instruct the user to remove the previous entry & exit
+	 */
+	for (p = 0; p < dev->port_cnt; p++) {
+		/* Skip the current sniffing port */
+		if (p == mirror->to_local_port)
+			continue;
+
+		ksz_pread8(dev, p, P_MIRROR_CTRL, &data);
+
+		if (data & PORT_MIRROR_SNIFFER) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Sniffer port is already configured, delete existing rules & retry");
+			return -EBUSY;
+		}
+	}
 
 	if (ingress)
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_RX, true);
 	else
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_TX, true);
 
-	ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_SNIFFER, false);
-
 	/* configure mirror port */
 	ksz_port_cfg(dev, mirror->to_local_port, P_MIRROR_CTRL,
 		     PORT_MIRROR_SNIFFER, true);
@@ -1042,16 +1060,28 @@ static void ksz9477_port_mirror_del(struct dsa_switch *ds, int port,
 				    struct dsa_mall_mirror_tc_entry *mirror)
 {
 	struct ksz_device *dev = ds->priv;
+	bool in_use = false;
 	u8 data;
+	int p;
 
 	if (mirror->ingress)
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_RX, false);
 	else
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_TX, false);
 
-	ksz_pread8(dev, port, P_MIRROR_CTRL, &data);
 
-	if (!(data & (PORT_MIRROR_RX | PORT_MIRROR_TX)))
+	/* Check if any of the port is still referring to sniffer port */
+	for (p = 0; p < dev->port_cnt; p++) {
+		ksz_pread8(dev, p, P_MIRROR_CTRL, &data);
+
+		if ((data & (PORT_MIRROR_RX | PORT_MIRROR_TX))) {
+			in_use = true;
+			break;
+		}
+	}
+
+	/* delete sniffing if there are no other mirroring rules */
+	if (!in_use)
 		ksz_port_cfg(dev, mirror->to_local_port, P_MIRROR_CTRL,
 			     PORT_MIRROR_SNIFFER, false);
 }