[PATCH net-next v4 5/9] net: dsa: microchip: ksz9477: Add Wake on Magic Packet support

[Oleksij Rempel <o.rempel@pengutronix.de>]

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>
---
 drivers/net/dsa/microchip/ksz9477.c    | 17 ++++++++++++++---
 drivers/net/dsa/microchip/ksz_common.c | 13 +++++++++++--
 drivers/net/dsa/microchip/ksz_common.h |  2 ++
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 8b512b55bfe5..1f8b37b510b0 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/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\"" : "");
 
@@ -111,12 +112,14 @@ void ksz9477_get_wol(struct ksz_device *dev, int port,
 	if (!(pme_conf & PME_ENABLE))
 		return;
 
-	wol->supported = WAKE_PHY;
+	wol->supported = WAKE_PHY | 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;
 }
@@ -141,7 +144,7 @@ int ksz9477_set_wol(struct ksz_device *dev, int port,
 	u8 pme_conf, pme_ctrl = 0;
 	int ret;
 
-	if (wol->wolopts & ~WAKE_PHY)
+	if (wol->wolopts & ~(WAKE_PHY | WAKE_MAGIC))
 		return -EINVAL;
 
 	ret = ksz_read8(dev, REG_SW_PME_CTRL, &pme_conf);
@@ -155,6 +158,14 @@ int ksz9477_set_wol(struct ksz_device *dev, int port,
 	if (ret)
 		return ret;
 
+	if (wol->wolopts & WAKE_MAGIC) {
+		ret = ksz_switch_macaddr_get(dev->ds, port, NULL);
+		if (ret)
+			return ret;
+
+		pme_ctrl |= PME_WOL_MAGICPKT;
+	}
+
 	if (wol->wolopts & WAKE_PHY)
 		pme_ctrl |= PME_WOL_LINKUP | PME_WOL_ENERGY;
 
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 3f7c86e545a7..4601aaca5179 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,
@@ -3577,6 +3578,14 @@ 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;
 }
 
@@ -3587,8 +3596,8 @@ 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 *slave = dsa_to_port(ds, port)->slave;
 	const unsigned char *addr = slave->dev_addr;
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index a7394175fcf6..2ad49c5f1df4 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -396,6 +396,8 @@ 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);
 
 /* Common register access functions */
 static inline struct regmap *ksz_regmap_8(struct ksz_device *dev)
-- 
2.39.2