[RFC PATCH v11 net-next 08/10] net: dsa: microchip: add support for port mirror operations

[Prasanna Vengateshan <prasanna.vengateshan@microchip.com>]

Added support for port_mirror_add() and port_mirror_del operations

Sniffing is limited to one port & alert the user if any new
sniffing port is selected

Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/dsa/microchip/lan937x_main.c | 83 ++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
index 51640234dda6..504b9a4edea2 100644
--- a/drivers/net/dsa/microchip/lan937x_main.c
+++ b/drivers/net/dsa/microchip/lan937x_main.c
@@ -98,6 +98,87 @@ static void lan937x_port_stp_state_set(struct dsa_switch *ds, int port,
 	ksz_update_port_member(dev, port);
 }
 
+static int lan937x_port_mirror_add(struct dsa_switch *ds, int port,
+				   struct dsa_mall_mirror_tc_entry *mirror,
+				   bool ingress, struct netlink_ext_ack *extack)
+{
+	struct ksz_device *dev = ds->priv;
+	int ret, p;
+	u8 data;
+
+	/* 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;
+
+		ret = lan937x_pread8(dev, p, P_MIRROR_CTRL, &data);
+		if (ret < 0)
+			return ret;
+
+		if (data & PORT_MIRROR_SNIFFER) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Sniffer port is already configured, delete existing rules & retry");
+			return -EBUSY;
+		}
+	}
+
+	/* Configure ingress/egress mirroring */
+	if (ingress)
+		ret = lan937x_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_RX,
+				       true);
+	else
+		ret = lan937x_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_TX,
+				       true);
+	if (ret < 0)
+		return ret;
+
+	/* Configure sniffer port as other ports do not have
+	 * PORT_MIRROR_SNIFFER is set
+	 */
+	ret = lan937x_port_cfg(dev, mirror->to_local_port, P_MIRROR_CTRL,
+			       PORT_MIRROR_SNIFFER, true);
+	if (ret < 0)
+		return ret;
+
+	return lan937x_cfg(dev, S_MIRROR_CTRL, SW_MIRROR_RX_TX, false);
+}
+
+static void lan937x_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;
+
+	/* clear ingress/egress mirroring port */
+	if (mirror->ingress)
+		lan937x_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_RX,
+				 false);
+	else
+		lan937x_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_TX,
+				 false);
+
+	/* Check if any of the port is still referring to sniffer port */
+	for (p = 0; p < dev->port_cnt; p++) {
+		lan937x_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 rule exist */
+	if (!in_use)
+		lan937x_port_cfg(dev, mirror->to_local_port, P_MIRROR_CTRL,
+				 PORT_MIRROR_SNIFFER, false);
+}
+
 static void lan937x_config_cpu_port(struct dsa_switch *ds)
 {
 	struct ksz_device *dev = ds->priv;
@@ -485,6 +566,8 @@ const struct dsa_switch_ops lan937x_switch_ops = {
 	.port_bridge_leave = ksz_port_bridge_leave,
 	.port_stp_state_set = lan937x_port_stp_state_set,
 	.port_fast_age = ksz_port_fast_age,
+	.port_mirror_add = lan937x_port_mirror_add,
+	.port_mirror_del = lan937x_port_mirror_del,
 	.port_max_mtu = lan937x_get_max_mtu,
 	.port_change_mtu = lan937x_change_mtu,
 	.phylink_get_caps = lan937x_phylink_get_caps,
-- 
2.30.2