usbcore: refine warm reset logic

Current waiting time for warm(BH) reset in hub_port_warm_reset() is too short
for xHC host to complete the warm reset and report a BH reset change.

This patch increases the waiting time for warm reset and merges the function
into hub_port_reset(), so it can handle both cold reset and warm reset, and
factor out hub_port_finish_reset() to make the code looks cleaner.

This fixes the issue that driver fails to clear BH reset change and port is
"dead".
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

@@ -2025,11 +2025,12 @@ static unsigned hub_is_wusb(struct usb_hub *hub)
 
 #define HUB_ROOT_RESET_TIME	50	/* times are in msec */
 #define HUB_SHORT_RESET_TIME	10
+#define HUB_BH_RESET_TIME	50
 #define HUB_LONG_RESET_TIME	200
 #define HUB_RESET_TIMEOUT	500
 
 static int hub_port_wait_reset(struct usb_hub *hub, int port1,
-				struct usb_device *udev, unsigned int delay)
+			struct usb_device *udev, unsigned int delay, bool warm)
 {
 	int delay_time, ret;
 	u16 portstatus;
@@ -2046,6 +2047,11 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
 		if (ret < 0)
 			return ret;
 
+		/*
+		 * Some buggy devices require a warm reset to be issued even
+		 * when the port appears not to be connected.
+		 */
+		if (!warm) {
 			/* Device went away? */
 			if (!(portstatus & USB_PORT_STAT_CONNECTION))
 				return -ENOTCONN;
@@ -2054,7 +2060,9 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
 			if ((portchange & USB_PORT_STAT_C_CONNECTION))
 				return -ENOTCONN;
 
-		/* if we`ve finished resetting, then break out of the loop */
+			/* if we`ve finished resetting, then break out of
+			 * the loop
+			 */
 			if (!(portstatus & USB_PORT_STAT_RESET) &&
 			    (portstatus & USB_PORT_STAT_ENABLE)) {
 				if (hub_is_wusb(hub))
@@ -2069,122 +2077,121 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
 					udev->speed = USB_SPEED_FULL;
 				return 0;
 			}
+		} else {
+			if (portchange & USB_PORT_STAT_C_BH_RESET)
+				return 0;
+		}
 
 		/* switch to the long delay after two short delay failures */
 		if (delay_time >= 2 * HUB_SHORT_RESET_TIME)
 			delay = HUB_LONG_RESET_TIME;
 
 		dev_dbg (hub->intfdev,
-			"port %d not reset yet, waiting %dms\n",
-			port1, delay);
+			"port %d not %sreset yet, waiting %dms\n",
+			port1, warm ? "warm " : "", delay);
 	}
 
 	return -EBUSY;
 }
 
-static int hub_port_reset(struct usb_hub *hub, int port1,
-				struct usb_device *udev, unsigned int delay)
+static void hub_port_finish_reset(struct usb_hub *hub, int port1,
+			struct usb_device *udev, int *status, bool warm)
 {
-	int i, status;
-	struct usb_hcd *hcd;
-
-	hcd = bus_to_hcd(udev->bus);
-	/* Block EHCI CF initialization during the port reset.
-	 * Some companion controllers don't like it when they mix.
-	 */
-	down_read(&ehci_cf_port_reset_rwsem);
-
-	/* Reset the port */
-	for (i = 0; i < PORT_RESET_TRIES; i++) {
-		status = set_port_feature(hub->hdev,
-				port1, USB_PORT_FEAT_RESET);
-		if (status)
-			dev_err(hub->intfdev,
-					"cannot reset port %d (err = %d)\n",
-					port1, status);
-		else {
-			status = hub_port_wait_reset(hub, port1, udev, delay);
-			if (status && status != -ENOTCONN)
-				dev_dbg(hub->intfdev,
-						"port_wait_reset: err = %d\n",
-						status);
-		}
-
-		/* return on disconnect or reset */
-		switch (status) {
+	switch (*status) {
 	case 0:
+		if (!warm) {
+			struct usb_hcd *hcd;
 			/* TRSTRCY = 10 ms; plus some extra */
 			msleep(10 + 40);
 			update_devnum(udev, 0);
+			hcd = bus_to_hcd(udev->bus);
 			if (hcd->driver->reset_device) {
-				status = hcd->driver->reset_device(hcd, udev);
-				if (status < 0) {
+				*status = hcd->driver->reset_device(hcd, udev);
+				if (*status < 0) {
 					dev_err(&udev->dev, "Cannot reset "
 							"HCD device state\n");
 					break;
 				}
 			}
+		}
 		/* FALL THROUGH */
 	case -ENOTCONN:
 	case -ENODEV:
 		clear_port_feature(hub->hdev,
 				port1, USB_PORT_FEAT_C_RESET);
 		/* FIXME need disconnect() for NOTATTACHED device */
-			usb_set_device_state(udev, status
+		if (warm) {
+			clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_BH_PORT_RESET);
+			clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_PORT_LINK_STATE);
+		} else {
+			usb_set_device_state(udev, *status
 					? USB_STATE_NOTATTACHED
 					: USB_STATE_DEFAULT);
-			goto done;
 		}
-
-		dev_dbg (hub->intfdev,
-			"port %d not enabled, trying reset again...\n",
-			port1);
-		delay = HUB_LONG_RESET_TIME;
+		break;
 	}
-
-	dev_err (hub->intfdev,
-		"Cannot enable port %i.  Maybe the USB cable is bad?\n",
-		port1);
-
- done:
-	up_read(&ehci_cf_port_reset_rwsem);
-	return status;
 }
 
-/* Warm reset a USB3 protocol port */
-static int hub_port_warm_reset(struct usb_hub *hub, int port)
+/* Handle port reset and port warm(BH) reset (for USB3 protocol ports) */
+static int hub_port_reset(struct usb_hub *hub, int port1,
+			struct usb_device *udev, unsigned int delay, bool warm)
 {
-	int ret;
-	u16 portstatus, portchange;
+	int i, status;
 
+	if (!warm) {
+		/* Block EHCI CF initialization during the port reset.
+		 * Some companion controllers don't like it when they mix.
+		 */
+		down_read(&ehci_cf_port_reset_rwsem);
+	} else {
 		if (!hub_is_superspeed(hub->hdev)) {
-		dev_err(hub->intfdev, "only USB3 hub support warm reset\n");
+			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;
+	/* Reset the port */
+	for (i = 0; i < PORT_RESET_TRIES; i++) {
+		status = set_port_feature(hub->hdev, port1, (warm ?
+					USB_PORT_FEAT_BH_PORT_RESET :
+					USB_PORT_FEAT_RESET));
+		if (status) {
+			dev_err(hub->intfdev,
+					"cannot %sreset port %d (err = %d)\n",
+					warm ? "warm " : "", port1, status);
+		} else {
+			status = hub_port_wait_reset(hub, port1, udev, delay,
+								warm);
+			if (status && status != -ENOTCONN)
+				dev_dbg(hub->intfdev,
+						"port_wait_reset: err = %d\n",
+						status);
 		}
 
-	msleep(20);
-	ret = hub_port_status(hub, port, &portstatus, &portchange);
+		/* return on disconnect or reset */
+		if (status == 0 || status == -ENOTCONN || status == -ENODEV) {
+			hub_port_finish_reset(hub, port1, udev, &status, warm);
+			goto done;
+		}
 
-	if (portchange & USB_PORT_STAT_C_RESET)
-		clear_port_feature(hub->hdev, port, USB_PORT_FEAT_C_RESET);
+		dev_dbg (hub->intfdev,
+			"port %d not enabled, trying %sreset again...\n",
+			port1, warm ? "warm " : "");
+		delay = HUB_LONG_RESET_TIME;
+	}
 
-	if (portchange & USB_PORT_STAT_C_BH_RESET)
-		clear_port_feature(hub->hdev, port,
-					USB_PORT_FEAT_C_BH_PORT_RESET);
+	dev_err (hub->intfdev,
+		"Cannot enable port %i.  Maybe the USB cable is bad?\n",
+		port1);
 
-	if (portchange & USB_PORT_STAT_C_LINK_STATE)
-		clear_port_feature(hub->hdev, port,
-					USB_PORT_FEAT_C_PORT_LINK_STATE);
+done:
+	if (!warm)
+		up_read(&ehci_cf_port_reset_rwsem);
 
-	return ret;
+	return status;
 }
 
 /* Check if a port is power on */
@@ -2814,7 +2821,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 
 	/* Reset the device; full speed may morph to high speed */
 	/* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */
-	retval = hub_port_reset(hub, port1, udev, delay);
+	retval = hub_port_reset(hub, port1, udev, delay, false);
 	if (retval < 0)		/* error or disconnect */
 		goto fail;
 	/* success, speed is known */
@@ -2935,7 +2942,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 					buf->bMaxPacketSize0;
 			kfree(buf);
 
-			retval = hub_port_reset(hub, port1, udev, delay);
+			retval = hub_port_reset(hub, port1, udev, delay, false);
 			if (retval < 0)		/* error or disconnect */
 				goto fail;
 			if (oldspeed != udev->speed) {
@@ -3556,7 +3563,8 @@ static void hub_events(void)
 				(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);
+				hub_port_reset(hub, i, NULL,
+						HUB_BH_RESET_TIME, true);
 			}
 
 			if (connect_change)