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>

1 files changed, 40 insertions, 3 deletions

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index de788f424a3f..8244204e177d 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/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,
@@ -3577,9 +3578,45 @@ 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
@@ -3587,8 +3624,8 @@ static int ksz_port_set_mac_address(struct dsa_switch *ds, int port,
  * 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;