thunderbolt: Add wake on connect/disconnect on USB4 ports

Wake on connect/disconnect is only supported while runtime suspend for
now, which is obviously necessary. It is also not inherently desired for
the system to wakeup on Thunderbolt/USB4 hot plug events. However, we
can still make user in control of waking up the system in the events of
hot plug/unplug.

This patch adds 'wakeup' attribute under 'usb4_portX/power' sysfs
attribute and only enables wakes on connect/disconnect to the respective
port when 'wakeup' is set to 'enabled'. The attribute is set to
'disabled' by default.
Signed-off-by: Rajat Khandelwal <rajat.khandelwal@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/tb_regs.h

@@ -361,6 +361,8 @@ struct tb_regs_port_header {
 #define PORT_CS_18_BE				BIT(8)
 #define PORT_CS_18_TCM				BIT(9)
 #define PORT_CS_18_CPS				BIT(10)
+#define PORT_CS_18_WOCS				BIT(16)
+#define PORT_CS_18_WODS				BIT(17)
 #define PORT_CS_18_WOU4S			BIT(18)
 #define PORT_CS_19				0x13
 #define PORT_CS_19_PC				BIT(3)

drivers/thunderbolt/usb4.c

@@ -155,6 +155,8 @@ static inline int usb4_switch_op_data(struct tb_switch *sw, u16 opcode,
 
 static void usb4_switch_check_wakes(struct tb_switch *sw)
 {
+	bool wakeup_usb4 = false;
+	struct usb4_port *usb4;
 	struct tb_port *port;
 	bool wakeup = false;
 	u32 val;
@@ -173,20 +175,31 @@ static void usb4_switch_check_wakes(struct tb_switch *sw)
 		wakeup = val & (ROUTER_CS_6_WOPS | ROUTER_CS_6_WOUS);
 	}
 
-	/* Check for any connected downstream ports for USB4 wake */
+	/*
+	 * Check for any downstream ports for USB4 wake,
+	 * connection wake and disconnection wake.
+	 */
 	tb_switch_for_each_port(sw, port) {
-		if (!tb_port_has_remote(port))
+		if (!port->cap_usb4)
 			continue;
 
 		if (tb_port_read(port, &val, TB_CFG_PORT,
 				 port->cap_usb4 + PORT_CS_18, 1))
 			break;
 
-		tb_port_dbg(port, "USB4 wake: %s\n",
-			    (val & PORT_CS_18_WOU4S) ? "yes" : "no");
+		tb_port_dbg(port, "USB4 wake: %s, connection wake: %s, disconnection wake: %s\n",
+			    (val & PORT_CS_18_WOU4S) ? "yes" : "no",
+			    (val & PORT_CS_18_WOCS) ? "yes" : "no",
+			    (val & PORT_CS_18_WODS) ? "yes" : "no");
+
+		wakeup_usb4 = val & (PORT_CS_18_WOU4S | PORT_CS_18_WOCS |
+				     PORT_CS_18_WODS);
+
+		usb4 = port->usb4;
+		if (device_may_wakeup(&usb4->dev) && wakeup_usb4)
+			pm_wakeup_event(&usb4->dev, 0);
 
-		if (val & PORT_CS_18_WOU4S)
-			wakeup = true;
+		wakeup |= wakeup_usb4;
 	}
 
 	if (wakeup)
@@ -366,6 +379,7 @@ bool usb4_switch_lane_bonding_possible(struct tb_switch *sw)
  */
 int usb4_switch_set_wake(struct tb_switch *sw, unsigned int flags)
 {
+	struct usb4_port *usb4;
 	struct tb_port *port;
 	u64 route = tb_route(sw);
 	u32 val;
@@ -395,10 +409,13 @@ int usb4_switch_set_wake(struct tb_switch *sw, unsigned int flags)
 			val |= PORT_CS_19_WOU4;
 		} else {
 			bool configured = val & PORT_CS_19_PC;
+			usb4 = port->usb4;
 
-			if ((flags & TB_WAKE_ON_CONNECT) && !configured)
+			if (((flags & TB_WAKE_ON_CONNECT) |
+			      device_may_wakeup(&usb4->dev)) && !configured)
 				val |= PORT_CS_19_WOC;
-			if ((flags & TB_WAKE_ON_DISCONNECT) && configured)
+			if (((flags & TB_WAKE_ON_DISCONNECT) |
+			      device_may_wakeup(&usb4->dev)) && configured)
 				val |= PORT_CS_19_WOD;
 			if ((flags & TB_WAKE_ON_USB4) && configured)
 				val |= PORT_CS_19_WOU4;

drivers/thunderbolt/usb4_port.c

@@ -284,6 +284,9 @@ struct usb4_port *usb4_port_device_add(struct tb_port *port)
 		}
 	}
 
+	if (!tb_is_upstream_port(port))
+		device_set_wakeup_capable(&usb4->dev, true);
+
 	pm_runtime_no_callbacks(&usb4->dev);
 	pm_runtime_set_active(&usb4->dev);
 	pm_runtime_enable(&usb4->dev);