net: dsa: microchip: ksz9477: Add Wake on Magic Packet support

Introduce Wake on Magic Packet (WoL) functionality to the ksz9477
driver.

Major changes include:

1. Extending the `ksz9477_handle_wake_reason` function to identify Magic
   Packet wake events alongside existing wake reasons.

2. Updating the `ksz9477_get_wol` and `ksz9477_set_wol` functions to
   handle WAKE_MAGIC alongside the existing WAKE_PHY option, and to
   program the switch's MAC address register accordingly when Magic
   Packet wake-up is enabled. This change will prevent WAKE_MAGIC
   activation if the related port has a different MAC address compared
   to a MAC address already used by HSR or an already active WAKE_MAGIC
   on another port.

3. Adding a restriction in `ksz_port_set_mac_address` to prevent MAC
   address changes on ports with active Wake on Magic Packet, as the
   switch's MAC address register is utilized for this feature.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20231026051051.2316937-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: olerem

drivers/net/dsa/microchip/ksz9477.c

@@ -81,7 +81,8 @@ static int ksz9477_handle_wake_reason(struct ksz_device *dev, int port)
 	if (!pme_status)
 		return 0;
 
-	dev_dbg(dev->dev, "Wake event on port %d due to:%s%s\n", port,
+	dev_dbg(dev->dev, "Wake event on port %d due to:%s%s%s\n", port,
+		pme_status & PME_WOL_MAGICPKT ? " \"Magic Packet\"" : "",
 		pme_status & PME_WOL_LINKUP ? " \"Link Up\"" : "",
 		pme_status & PME_WOL_ENERGY ? " \"Enery detect\"" : "");
 
@@ -109,10 +110,19 @@ void ksz9477_get_wol(struct ksz_device *dev, int port,
 
 	wol->supported = WAKE_PHY;
 
+	/* Check if the current MAC address on this port can be set
+	 * as global for WAKE_MAGIC support. The result may vary
+	 * dynamically based on other ports configurations.
+	 */
+	if (ksz_is_port_mac_global_usable(dev->ds, port))
+		wol->supported |= WAKE_MAGIC;
+
 	ret = ksz_pread8(dev, port, REG_PORT_PME_CTRL, &pme_ctrl);
 	if (ret)
 		return;
 
+	if (pme_ctrl & PME_WOL_MAGICPKT)
+		wol->wolopts |= WAKE_MAGIC;
 	if (pme_ctrl & (PME_WOL_LINKUP | PME_WOL_ENERGY))
 		wol->wolopts |= WAKE_PHY;
 }
@@ -134,10 +144,12 @@ void ksz9477_get_wol(struct ksz_device *dev, int port,
 int ksz9477_set_wol(struct ksz_device *dev, int port,
 		    struct ethtool_wolinfo *wol)
 {
-	u8 pme_ctrl = 0;
+	u8 pme_ctrl = 0, pme_ctrl_old = 0;
+	bool magic_switched_off;
+	bool magic_switched_on;
 	int ret;
 
-	if (wol->wolopts & ~WAKE_PHY)
+	if (wol->wolopts & ~(WAKE_PHY | WAKE_MAGIC))
 		return -EINVAL;
 
 	if (!dev->wakeup_source)
@@ -147,10 +159,42 @@ int ksz9477_set_wol(struct ksz_device *dev, int port,
 	if (ret)
 		return ret;
 
+	if (wol->wolopts & WAKE_MAGIC)
+		pme_ctrl |= PME_WOL_MAGICPKT;
 	if (wol->wolopts & WAKE_PHY)
 		pme_ctrl |= PME_WOL_LINKUP | PME_WOL_ENERGY;
 
-	return ksz_pwrite8(dev, port, REG_PORT_PME_CTRL, pme_ctrl);
+	ret = ksz_pread8(dev, port, REG_PORT_PME_CTRL, &pme_ctrl_old);
+	if (ret)
+		return ret;
+
+	if (pme_ctrl_old == pme_ctrl)
+		return 0;
+
+	magic_switched_off = (pme_ctrl_old & PME_WOL_MAGICPKT) &&
+			    !(pme_ctrl & PME_WOL_MAGICPKT);
+	magic_switched_on = !(pme_ctrl_old & PME_WOL_MAGICPKT) &&
+			    (pme_ctrl & PME_WOL_MAGICPKT);
+
+	/* To keep reference count of MAC address, we should do this
+	 * operation only on change of WOL settings.
+	 */
+	if (magic_switched_on) {
+		ret = ksz_switch_macaddr_get(dev->ds, port, NULL);
+		if (ret)
+			return ret;
+	} else if (magic_switched_off) {
+		ksz_switch_macaddr_put(dev->ds);
+	}
+
+	ret = ksz_pwrite8(dev, port, REG_PORT_PME_CTRL, pme_ctrl);
+	if (ret) {
+		if (magic_switched_on)
+			ksz_switch_macaddr_put(dev->ds);
+		return ret;
+	}
+
+	return 0;
 }
 
 static int ksz9477_wait_vlan_ctrl_ready(struct ksz_device *dev)
@@ -1106,6 +1150,11 @@ void ksz9477_port_setup(struct ksz_device *dev, int port, bool cpu_port)
 
 	/* clear pending wake flags */
 	ksz9477_handle_wake_reason(dev, port);
+
+	/* Disable all WoL options by default. Otherwise
+	 * ksz_switch_macaddr_get/put logic will not work properly.
+	 */
+	ksz_pwrite8(dev, port, REG_PORT_PME_CTRL, 0);
 }
 
 void ksz9477_config_cpu_port(struct dsa_switch *ds)

drivers/net/dsa/microchip/ksz_common.c

@@ -3569,6 +3569,7 @@ static int ksz_port_set_mac_address(struct dsa_switch *ds, int port,
 				    const unsigned char *addr)
 {
 	struct dsa_port *dp = dsa_to_port(ds, port);
+	struct ethtool_wolinfo wol;
 
 	if (dp->hsr_dev) {
 		dev_err(ds->dev,
@@ -3577,18 +3578,54 @@ static int ksz_port_set_mac_address(struct dsa_switch *ds, int port,
 		return -EBUSY;
 	}
 
+	ksz_get_wol(ds, dp->index, &wol);
+	if (wol.wolopts & WAKE_MAGIC) {
+		dev_err(ds->dev,
+			"Cannot change MAC address on port %d with active Wake on Magic Packet\n",
+			port);
+		return -EBUSY;
+	}
+
 	return 0;
 }
 
+/**
+ * ksz_is_port_mac_global_usable - Check if the MAC address on a given port
+ *                                 can be used as a global address.
+ * @ds: Pointer to the DSA switch structure.
+ * @port: The port number on which the MAC address is to be checked.
+ *
+ * This function examines the MAC address set on the specified port and
+ * determines if it can be used as a global address for the switch.
+ *
+ * Return: true if the port's MAC address can be used as a global address, false
+ * otherwise.
+ */
+bool ksz_is_port_mac_global_usable(struct dsa_switch *ds, int port)
+{
+	struct net_device *user = dsa_to_port(ds, port)->user;
+	const unsigned char *addr = user->dev_addr;
+	struct ksz_switch_macaddr *switch_macaddr;
+	struct ksz_device *dev = ds->priv;
+
+	ASSERT_RTNL();
+
+	switch_macaddr = dev->switch_macaddr;
+	if (switch_macaddr && !ether_addr_equal(switch_macaddr->addr, addr))
+		return false;
+
+	return true;
+}
+
 /* Program the switch's MAC address register with the MAC address of the
  * requesting user port. This single address is used by the switch for multiple
  * features, like HSR self-address filtering and WoL. Other user ports are
  * allowed to share ownership of this address as long as their MAC address is
  * the same. The user ports' MAC addresses must not change while they have
  * ownership of the switch MAC address.
  */
-static int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
-				  struct netlink_ext_ack *extack)
+int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
+			   struct netlink_ext_ack *extack)
 {
 	struct net_device *user = dsa_to_port(ds, port)->user;
 	const unsigned char *addr = user->dev_addr;
@@ -3628,7 +3665,7 @@ static int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
 	return 0;
 }
 
-static void ksz_switch_macaddr_put(struct dsa_switch *ds)
+void ksz_switch_macaddr_put(struct dsa_switch *ds)
 {
 	struct ksz_switch_macaddr *switch_macaddr;
 	struct ksz_device *dev = ds->priv;

drivers/net/dsa/microchip/ksz_common.h

@@ -390,12 +390,16 @@ int ksz_switch_register(struct ksz_device *dev);
 void ksz_switch_remove(struct ksz_device *dev);
 
 void ksz_init_mib_timer(struct ksz_device *dev);
+bool ksz_is_port_mac_global_usable(struct dsa_switch *ds, int port);
 void ksz_r_mib_stats64(struct ksz_device *dev, int port);
 void ksz88xx_r_mib_stats64(struct ksz_device *dev, int port);
 void ksz_port_stp_state_set(struct dsa_switch *ds, int port, u8 state);
 bool ksz_get_gbit(struct ksz_device *dev, int port);
 phy_interface_t ksz_get_xmii(struct ksz_device *dev, int port, bool gbit);
 extern const struct ksz_chip_data ksz_switch_chips[];
+int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
+			   struct netlink_ext_ack *extack);
+void ksz_switch_macaddr_put(struct dsa_switch *ds);
 
 /* Common register access functions */
 static inline struct regmap *ksz_regmap_8(struct ksz_device *dev)