usbcore: warm reset USB3 port in SS.Inactive state

Some USB3.0 devices go to SS.Inactive state when hot plug to USB3 ports.
Warm reset the port to transition it to U0 state.

This patch fixes the issue that Kingston USB3.0 flash drive can not be
recognized when hot plug to USB3 port.
Signed-off-by: NAndiry Xu <andiry.xu@amd.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/usb/core/hub.c

@@ -2151,6 +2151,42 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
 	return status;
 }
 
+/* Warm reset a USB3 protocol port */
+static int hub_port_warm_reset(struct usb_hub *hub, int port)
+{
+	int ret;
+	u16 portstatus, portchange;
+
+	if (!hub_is_superspeed(hub->hdev)) {
+		dev_err(hub->intfdev, "only USB3 hub support warm reset\n");
+		return -EINVAL;
+	}
+
+	/* Warm reset the port */
+	ret = set_port_feature(hub->hdev,
+				port, USB_PORT_FEAT_BH_PORT_RESET);
+	if (ret) {
+		dev_err(hub->intfdev, "cannot warm reset port %d\n", port);
+		return ret;
+	}
+
+	msleep(20);
+	ret = hub_port_status(hub, port, &portstatus, &portchange);
+
+	if (portchange & USB_PORT_STAT_C_RESET)
+		clear_port_feature(hub->hdev, port, USB_PORT_FEAT_C_RESET);
+
+	if (portchange & USB_PORT_STAT_C_BH_RESET)
+		clear_port_feature(hub->hdev, port,
+					USB_PORT_FEAT_C_BH_PORT_RESET);
+
+	if (portchange & USB_PORT_STAT_C_LINK_STATE)
+		clear_port_feature(hub->hdev, port,
+					USB_PORT_FEAT_C_PORT_LINK_STATE);
+
+	return ret;
+}
+
 /* Check if a port is power on */
 static int port_is_power_on(struct usb_hub *hub, unsigned portstatus)
 {
@@ -3519,6 +3555,16 @@ static void hub_events(void)
 						USB_PORT_FEAT_C_PORT_CONFIG_ERROR);
 			}
 
+			/* Warm reset a USB3 protocol port if it's in
+			 * SS.Inactive state.
+			 */
+			if (hub_is_superspeed(hub->hdev) &&
+				(portstatus & USB_PORT_STAT_LINK_STATE)
+					== USB_SS_PORT_LS_SS_INACTIVE) {
+				dev_dbg(hub_dev, "warm reset port %d\n", i);
+				hub_port_warm_reset(hub, i);
+			}
+
 			if (connect_change)
 				hub_port_connect_change(hub, i,
 						portstatus, portchange);