net: dsa: microchip: ksz9477: add Wake on LAN support

Add WoL support for KSZ9477 family of switches. This code was tested on
KSZ8563 chip.

KSZ9477 family of switches supports multiple PHY events:
- wake on Link Up
- wake on Energy Detect.
Since current UAPI can't differentiate between this PHY events, map all
of them to WAKE_PHY.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/ksz9477.c

@@ -56,6 +56,103 @@ int ksz9477_change_mtu(struct ksz_device *dev, int port, int mtu)
 				  REG_SW_MTU_MASK, frame_size);
 }
 
+/**
+ * ksz9477_handle_wake_reason - Handle wake reason on a specified port.
+ * @dev: The device structure.
+ * @port: The port number.
+ *
+ * This function reads the PME (Power Management Event) status register of a
+ * specified port to determine the wake reason. If there is no wake event, it
+ * returns early. Otherwise, it logs the wake reason which could be due to a
+ * "Magic Packet", "Link Up", or "Energy Detect" event. The PME status register
+ * is then cleared to acknowledge the handling of the wake event.
+ *
+ * Return: 0 on success, or an error code on failure.
+ */
+static int ksz9477_handle_wake_reason(struct ksz_device *dev, int port)
+{
+	u8 pme_status;
+	int ret;
+
+	ret = ksz_pread8(dev, port, REG_PORT_PME_STATUS, &pme_status);
+	if (ret)
+		return ret;
+
+	if (!pme_status)
+		return 0;
+
+	dev_dbg(dev->dev, "Wake event on port %d due to:%s%s\n", port,
+		pme_status & PME_WOL_LINKUP ? " \"Link Up\"" : "",
+		pme_status & PME_WOL_ENERGY ? " \"Enery detect\"" : "");
+
+	return ksz_pwrite8(dev, port, REG_PORT_PME_STATUS, pme_status);
+}
+
+/**
+ * ksz9477_get_wol - Get Wake-on-LAN settings for a specified port.
+ * @dev: The device structure.
+ * @port: The port number.
+ * @wol: Pointer to ethtool Wake-on-LAN settings structure.
+ *
+ * This function checks the PME Pin Control Register to see if  PME Pin Output
+ * Enable is set, indicating PME is enabled. If enabled, it sets the supported
+ * and active WoL flags.
+ */
+void ksz9477_get_wol(struct ksz_device *dev, int port,
+		     struct ethtool_wolinfo *wol)
+{
+	u8 pme_ctrl;
+	int ret;
+
+	if (!dev->wakeup_source)
+		return;
+
+	wol->supported = WAKE_PHY;
+
+	ret = ksz_pread8(dev, port, REG_PORT_PME_CTRL, &pme_ctrl);
+	if (ret)
+		return;
+
+	if (pme_ctrl & (PME_WOL_LINKUP | PME_WOL_ENERGY))
+		wol->wolopts |= WAKE_PHY;
+}
+
+/**
+ * ksz9477_set_wol - Set Wake-on-LAN settings for a specified port.
+ * @dev: The device structure.
+ * @port: The port number.
+ * @wol: Pointer to ethtool Wake-on-LAN settings structure.
+ *
+ * This function configures Wake-on-LAN (WoL) settings for a specified port.
+ * It validates the provided WoL options, checks if PME is enabled via the
+ * switch's PME Pin Control Register, clears any previous wake reasons,
+ * and sets the Magic Packet flag in the port's PME control register if
+ * specified.
+ *
+ * Return: 0 on success, or other error codes on failure.
+ */
+int ksz9477_set_wol(struct ksz_device *dev, int port,
+		    struct ethtool_wolinfo *wol)
+{
+	u8 pme_ctrl = 0;
+	int ret;
+
+	if (wol->wolopts & ~WAKE_PHY)
+		return -EINVAL;
+
+	if (!dev->wakeup_source)
+		return -EOPNOTSUPP;
+
+	ret = ksz9477_handle_wake_reason(dev, port);
+	if (ret)
+		return ret;
+
+	if (wol->wolopts & WAKE_PHY)
+		pme_ctrl |= PME_WOL_LINKUP | PME_WOL_ENERGY;
+
+	return ksz_pwrite8(dev, port, REG_PORT_PME_CTRL, pme_ctrl);
+}
+
 static int ksz9477_wait_vlan_ctrl_ready(struct ksz_device *dev)
 {
 	unsigned int val;
@@ -1006,6 +1103,9 @@ void ksz9477_port_setup(struct ksz_device *dev, int port, bool cpu_port)
 		ksz_pread16(dev, port, REG_PORT_PHY_INT_ENABLE, &data16);
 
 	ksz9477_port_acl_init(dev, port);
+
+	/* clear pending wake flags */
+	ksz9477_handle_wake_reason(dev, port);
 }
 
 void ksz9477_config_cpu_port(struct dsa_switch *ds)

drivers/net/dsa/microchip/ksz9477.h

@@ -58,6 +58,10 @@ void ksz9477_switch_exit(struct ksz_device *dev);
 void ksz9477_port_queue_split(struct ksz_device *dev, int port);
 void ksz9477_hsr_join(struct dsa_switch *ds, int port, struct net_device *hsr);
 void ksz9477_hsr_leave(struct dsa_switch *ds, int port, struct net_device *hsr);
+void ksz9477_get_wol(struct ksz_device *dev, int port,
+		     struct ethtool_wolinfo *wol);
+int ksz9477_set_wol(struct ksz_device *dev, int port,
+		    struct ethtool_wolinfo *wol);
 
 int ksz9477_port_acl_init(struct ksz_device *dev, int port);
 void ksz9477_port_acl_free(struct ksz_device *dev, int port);

drivers/net/dsa/microchip/ksz_common.c

@@ -319,6 +319,8 @@ static const struct ksz_dev_ops ksz9477_dev_ops = {
 	.mdb_del = ksz9477_mdb_del,
 	.change_mtu = ksz9477_change_mtu,
 	.phylink_mac_link_up = ksz9477_phylink_mac_link_up,
+	.get_wol = ksz9477_get_wol,
+	.set_wol = ksz9477_set_wol,
 	.config_cpu_port = ksz9477_config_cpu_port,
 	.tc_cbs_set_cinc = ksz9477_tc_cbs_set_cinc,
 	.enable_stp_addr = ksz9477_enable_stp_addr,
@@ -3543,6 +3545,26 @@ static int ksz_setup_tc(struct dsa_switch *ds, int port,
 	}
 }
 
+static void ksz_get_wol(struct dsa_switch *ds, int port,
+			struct ethtool_wolinfo *wol)
+{
+	struct ksz_device *dev = ds->priv;
+
+	if (dev->dev_ops->get_wol)
+		dev->dev_ops->get_wol(dev, port, wol);
+}
+
+static int ksz_set_wol(struct dsa_switch *ds, int port,
+		       struct ethtool_wolinfo *wol)
+{
+	struct ksz_device *dev = ds->priv;
+
+	if (dev->dev_ops->set_wol)
+		return dev->dev_ops->set_wol(dev, port, wol);
+
+	return -EOPNOTSUPP;
+}
+
 static int ksz_port_set_mac_address(struct dsa_switch *ds, int port,
 				    const unsigned char *addr)
 {
@@ -3727,6 +3749,8 @@ static const struct dsa_switch_ops ksz_switch_ops = {
 	.get_pause_stats	= ksz_get_pause_stats,
 	.port_change_mtu	= ksz_change_mtu,
 	.port_max_mtu		= ksz_max_mtu,
+	.get_wol		= ksz_get_wol,
+	.set_wol		= ksz_set_wol,
 	.get_ts_info		= ksz_get_ts_info,
 	.port_hwtstamp_get	= ksz_hwtstamp_get,
 	.port_hwtstamp_set	= ksz_hwtstamp_set,

drivers/net/dsa/microchip/ksz_common.h

@@ -374,6 +374,10 @@ struct ksz_dev_ops {
 				    int duplex, bool tx_pause, bool rx_pause);
 	void (*setup_rgmii_delay)(struct ksz_device *dev, int port);
 	int (*tc_cbs_set_cinc)(struct ksz_device *dev, int port, u32 val);
+	void (*get_wol)(struct ksz_device *dev, int port,
+			struct ethtool_wolinfo *wol);
+	int (*set_wol)(struct ksz_device *dev, int port,
+		       struct ethtool_wolinfo *wol);
 	void (*config_cpu_port)(struct dsa_switch *ds);
 	int (*enable_stp_addr)(struct ksz_device *dev);
 	int (*reset)(struct ksz_device *dev);