net: dsa: microchip: lan937x: add MTU and fast_age support

This patch add the support for port_max_mtu, port_change_mtu and
port_fast_age dsa functionality.
Signed-off-by: NArun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/ksz_common.c

@@ -206,6 +206,7 @@ static const struct ksz_dev_ops lan937x_dev_ops = {
 	.setup = lan937x_setup,
 	.get_port_addr = ksz9477_get_port_addr,
 	.cfg_port_member = ksz9477_cfg_port_member,
+	.flush_dyn_mac_table = ksz9477_flush_dyn_mac_table,
 	.port_setup = lan937x_port_setup,
 	.r_phy = lan937x_r_phy,
 	.w_phy = lan937x_w_phy,
@@ -224,6 +225,7 @@ static const struct ksz_dev_ops lan937x_dev_ops = {
 	.fdb_del = ksz9477_fdb_del,
 	.mdb_add = ksz9477_mdb_add,
 	.mdb_del = ksz9477_mdb_del,
+	.change_mtu = lan937x_change_mtu,
 	.max_mtu = ksz9477_max_mtu,
 	.config_cpu_port = lan937x_config_cpu_port,
 	.enable_stp_addr = ksz9477_enable_stp_addr,

drivers/net/dsa/microchip/lan937x.h

@@ -14,4 +14,5 @@ int lan937x_switch_init(struct ksz_device *dev);
 void lan937x_switch_exit(struct ksz_device *dev);
 void lan937x_r_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 *data);
 void lan937x_w_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 val);
+int lan937x_change_mtu(struct ksz_device *dev, int port, int new_mtu);
 #endif

drivers/net/dsa/microchip/lan937x_main.c

@@ -9,6 +9,7 @@
 #include <linux/of_net.h>
 #include <linux/of_mdio.h>
 #include <linux/if_bridge.h>
+#include <linux/if_vlan.h>
 #include <linux/math.h>
 #include <net/dsa.h>
 #include <net/switchdev.h>
@@ -284,6 +285,33 @@ void lan937x_config_cpu_port(struct dsa_switch *ds)
 	}
 }
 
+int lan937x_change_mtu(struct ksz_device *dev, int port, int new_mtu)
+{
+	struct dsa_switch *ds = dev->ds;
+	int ret;
+
+	new_mtu += VLAN_ETH_HLEN + ETH_FCS_LEN;
+
+	if (dsa_is_cpu_port(ds, port))
+		new_mtu += LAN937X_TAG_LEN;
+
+	if (new_mtu >= FR_MIN_SIZE)
+		ret = lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_0,
+				       PORT_JUMBO_PACKET, true);
+	else
+		ret = lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_0,
+				       PORT_JUMBO_PACKET, false);
+	if (ret < 0) {
+		dev_err(ds->dev, "failed to enable jumbo\n");
+		return ret;
+	}
+
+	/* Write the frame size in PORT_MAX_FR_SIZE register */
+	ksz_pwrite16(dev, port, PORT_MAX_FR_SIZE, new_mtu);
+
+	return 0;
+}
+
 int lan937x_setup(struct dsa_switch *ds)
 {
 	struct ksz_device *dev = ds->priv;

drivers/net/dsa/microchip/lan937x_reg.h

@@ -149,6 +149,9 @@
 #define PORT_BACK_PRESSURE		BIT(3)
 #define PORT_PASS_ALL			BIT(0)
 
+#define PORT_MAX_FR_SIZE		0x404
+#define FR_MIN_SIZE		1522
+
 /* 8 - Classification and Policing */
 #define REG_PORT_MRI_PRIO_CTRL		0x0801
 #define PORT_HIGHEST_PRIO		BIT(7)
@@ -161,4 +164,6 @@
 
 #define P_PRIO_CTRL			REG_PORT_MRI_PRIO_CTRL
 
+#define LAN937X_TAG_LEN			2
+
 #endif