Initial import

1 files changed, 5670 insertions, 0 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
new file mode 100644
index 000000000..8f9ff4d4c
--- /dev/null
+++ b/drivers/usb/core/hub.c
@@ -0,0 +1,5670 @@
+/*
+ * USB hub driver.
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ * (C) Copyright 1999 Johannes Erdfelt
+ * (C) Copyright 1999 Gregory P. Smith
+ * (C) Copyright 2001 Brad Hards (bhards@bigpond.net.au)
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/completion.h>
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/ioctl.h>
+#include <linux/usb.h>
+#include <linux/usbdevice_fs.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/quirks.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/random.h>
+#include <linux/pm_qos.h>
+
+#include <asm/uaccess.h>
+#include <asm/byteorder.h>
+
+#include "hub.h"
+#include "otg_whitelist.h"
+
+#define USB_VENDOR_GENESYS_LOGIC		0x05e3
+#define HUB_QUIRK_CHECK_PORT_AUTOSUSPEND	0x01
+
+/* Protect struct usb_device->state and ->children members
+ * Note: Both are also protected by ->dev.sem, except that ->state can
+ * change to USB_STATE_NOTATTACHED even when the semaphore isn't held. */
+static DEFINE_SPINLOCK(device_state_lock);
+
+/* workqueue to process hub events */
+static struct workqueue_struct *hub_wq;
+static void hub_event(struct work_struct *work);
+
+/* synchronize hub-port add/remove and peering operations */
+DEFINE_MUTEX(usb_port_peer_mutex);
+
+/* cycle leds on hubs that aren't blinking for attention */
+static bool blinkenlights = 0;
+module_param (blinkenlights, bool, S_IRUGO);
+MODULE_PARM_DESC (blinkenlights, "true to cycle leds on hubs");
+
+/*
+ * Device SATA8000 FW1.0 from DATAST0R Technology Corp requires about
+ * 10 seconds to send reply for the initial 64-byte descriptor request.
+ */
+/* define initial 64-byte descriptor request timeout in milliseconds */
+static int initial_descriptor_timeout = USB_CTRL_GET_TIMEOUT;
+module_param(initial_descriptor_timeout, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(initial_descriptor_timeout,
+		"initial 64-byte descriptor request timeout in milliseconds "
+		"(default 5000 - 5.0 seconds)");
+
+/*
+ * As of 2.6.10 we introduce a new USB device initialization scheme which
+ * closely resembles the way Windows works.  Hopefully it will be compatible
+ * with a wider range of devices than the old scheme.  However some previously
+ * working devices may start giving rise to "device not accepting address"
+ * errors; if that happens the user can try the old scheme by adjusting the
+ * following module parameters.
+ *
+ * For maximum flexibility there are two boolean parameters to control the
+ * hub driver's behavior.  On the first initialization attempt, if the
+ * "old_scheme_first" parameter is set then the old scheme will be used,
+ * otherwise the new scheme is used.  If that fails and "use_both_schemes"
+ * is set, then the driver will make another attempt, using the other scheme.
+ */
+static bool old_scheme_first = 0;
+module_param(old_scheme_first, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(old_scheme_first,
+		 "start with the old device initialization scheme");
+
+static bool use_both_schemes = 1;
+module_param(use_both_schemes, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(use_both_schemes,
+		"try the other device initialization scheme if the "
+		"first one fails");
+
+/* Mutual exclusion for EHCI CF initialization.  This interferes with
+ * port reset on some companion controllers.
+ */
+DECLARE_RWSEM(ehci_cf_port_reset_rwsem);
+EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem);
+
+#define HUB_DEBOUNCE_TIMEOUT	2000
+#define HUB_DEBOUNCE_STEP	  25
+#define HUB_DEBOUNCE_STABLE	 100
+
+static void hub_release(struct kref *kref);
+static int usb_reset_and_verify_device(struct usb_device *udev);
+
+static inline char *portspeed(struct usb_hub *hub, int portstatus)
+{
+	if (hub_is_superspeed(hub->hdev))
+		return "5.0 Gb/s";
+	if (portstatus & USB_PORT_STAT_HIGH_SPEED)
+		return "480 Mb/s";
+	else if (portstatus & USB_PORT_STAT_LOW_SPEED)
+		return "1.5 Mb/s";
+	else
+		return "12 Mb/s";
+}
+
+/* Note that hdev or one of its children must be locked! */
+struct usb_hub *usb_hub_to_struct_hub(struct usb_device *hdev)
+{
+	if (!hdev || !hdev->actconfig || !hdev->maxchild)
+		return NULL;
+	return usb_get_intfdata(hdev->actconfig->interface[0]);
+}
+
+int usb_device_supports_lpm(struct usb_device *udev)
+{
+	/* USB 2.1 (and greater) devices indicate LPM support through
+	 * their USB 2.0 Extended Capabilities BOS descriptor.
+	 */
+	if (udev->speed == USB_SPEED_HIGH) {
+		if (udev->bos->ext_cap &&
+			(USB_LPM_SUPPORT &
+			 le32_to_cpu(udev->bos->ext_cap->bmAttributes)))
+			return 1;
+		return 0;
+	}
+
+	/*
+	 * According to the USB 3.0 spec, all USB 3.0 devices must support LPM.
+	 * However, there are some that don't, and they set the U1/U2 exit
+	 * latencies to zero.
+	 */
+	if (!udev->bos->ss_cap) {
+		dev_info(&udev->dev, "No LPM exit latency info found, disabling LPM.\n");
+		return 0;
+	}
+
+	if (udev->bos->ss_cap->bU1devExitLat == 0 &&
+			udev->bos->ss_cap->bU2DevExitLat == 0) {
+		if (udev->parent)
+			dev_info(&udev->dev, "LPM exit latency is zeroed, disabling LPM.\n");
+		else
+			dev_info(&udev->dev, "We don't know the algorithms for LPM for this host, disabling LPM.\n");
+		return 0;
+	}
+
+	if (!udev->parent || udev->parent->lpm_capable)
+		return 1;
+	return 0;
+}
+
+/*
+ * Set the Maximum Exit Latency (MEL) for the host to initiate a transition from
+ * either U1 or U2.
+ */
+static void usb_set_lpm_mel(struct usb_device *udev,
+		struct usb3_lpm_parameters *udev_lpm_params,
+		unsigned int udev_exit_latency,
+		struct usb_hub *hub,
+		struct usb3_lpm_parameters *hub_lpm_params,
+		unsigned int hub_exit_latency)
+{
+	unsigned int total_mel;
+	unsigned int device_mel;
+	unsigned int hub_mel;
+
+	/*
+	 * Calculate the time it takes to transition all links from the roothub
+	 * to the parent hub into U0.  The parent hub must then decode the
+	 * packet (hub header decode latency) to figure out which port it was
+	 * bound for.
+	 *
+	 * The Hub Header decode latency is expressed in 0.1us intervals (0x1
+	 * means 0.1us).  Multiply that by 100 to get nanoseconds.
+	 */
+	total_mel = hub_lpm_params->mel +
+		(hub->descriptor->u.ss.bHubHdrDecLat * 100);
+
+	/*
+	 * How long will it take to transition the downstream hub's port into
+	 * U0?  The greater of either the hub exit latency or the device exit
+	 * latency.
+	 *
+	 * The BOS U1/U2 exit latencies are expressed in 1us intervals.
+	 * Multiply that by 1000 to get nanoseconds.
+	 */
+	device_mel = udev_exit_latency * 1000;
+	hub_mel = hub_exit_latency * 1000;
+	if (device_mel > hub_mel)
+		total_mel += device_mel;
+	else
+		total_mel += hub_mel;
+
+	udev_lpm_params->mel = total_mel;
+}
+
+/*
+ * Set the maximum Device to Host Exit Latency (PEL) for the device to initiate
+ * a transition from either U1 or U2.
+ */
+static void usb_set_lpm_pel(struct usb_device *udev,
+		struct usb3_lpm_parameters *udev_lpm_params,
+		unsigned int udev_exit_latency,
+		struct usb_hub *hub,
+		struct usb3_lpm_parameters *hub_lpm_params,
+		unsigned int hub_exit_latency,
+		unsigned int port_to_port_exit_latency)
+{
+	unsigned int first_link_pel;
+	unsigned int hub_pel;
+
+	/*
+	 * First, the device sends an LFPS to transition the link between the
+	 * device and the parent hub into U0.  The exit latency is the bigger of
+	 * the device exit latency or the hub exit latency.
+	 */
+	if (udev_exit_latency > hub_exit_latency)
+		first_link_pel = udev_exit_latency * 1000;
+	else
+		first_link_pel = hub_exit_latency * 1000;
+
+	/*
+	 * When the hub starts to receive the LFPS, there is a slight delay for
+	 * it to figure out that one of the ports is sending an LFPS.  Then it
+	 * will forward the LFPS to its upstream link.  The exit latency is the
+	 * delay, plus the PEL that we calculated for this hub.
+	 */
+	hub_pel = port_to_port_exit_latency * 1000 + hub_lpm_params->pel;
+
+	/*
+	 * According to figure C-7 in the USB 3.0 spec, the PEL for this device
+	 * is the greater of the two exit latencies.
+	 */
+	if (first_link_pel > hub_pel)
+		udev_lpm_params->pel = first_link_pel;
+	else
+		udev_lpm_params->pel = hub_pel;
+}
+
+/*
+ * Set the System Exit Latency (SEL) to indicate the total worst-case time from
+ * when a device initiates a transition to U0, until when it will receive the
+ * first packet from the host controller.
+ *
+ * Section C.1.5.1 describes the four components to this:
+ *  - t1: device PEL
+ *  - t2: time for the ERDY to make it from the device to the host.
+ *  - t3: a host-specific delay to process the ERDY.
+ *  - t4: time for the packet to make it from the host to the device.
+ *
+ * t3 is specific to both the xHCI host and the platform the host is integrated
+ * into.  The Intel HW folks have said it's negligible, FIXME if a different
+ * vendor says otherwise.
+ */
+static void usb_set_lpm_sel(struct usb_device *udev,
+		struct usb3_lpm_parameters *udev_lpm_params)
+{
+	struct usb_device *parent;
+	unsigned int num_hubs;
+	unsigned int total_sel;
+
+	/* t1 = device PEL */
+	total_sel = udev_lpm_params->pel;
+	/* How many external hubs are in between the device & the root port. */
+	for (parent = udev->parent, num_hubs = 0; parent->parent;
+			parent = parent->parent)
+		num_hubs++;
+	/* t2 = 2.1us + 250ns * (num_hubs - 1) */
+	if (num_hubs > 0)
+		total_sel += 2100 + 250 * (num_hubs - 1);
+
+	/* t4 = 250ns * num_hubs */
+	total_sel += 250 * num_hubs;
+
+	udev_lpm_params->sel = total_sel;
+}
+
+static void usb_set_lpm_parameters(struct usb_device *udev)
+{
+	struct usb_hub *hub;
+	unsigned int port_to_port_delay;
+	unsigned int udev_u1_del;
+	unsigned int udev_u2_del;
+	unsigned int hub_u1_del;
+	unsigned int hub_u2_del;
+
+	if (!udev->lpm_capable || udev->speed != USB_SPEED_SUPER)
+		return;
+
+	hub = usb_hub_to_struct_hub(udev->parent);
+	/* It doesn't take time to transition the roothub into U0, since it
+	 * doesn't have an upstream link.
+	 */
+	if (!hub)
+		return;
+
+	udev_u1_del = udev->bos->ss_cap->bU1devExitLat;
+	udev_u2_del = le16_to_cpu(udev->bos->ss_cap->bU2DevExitLat);
+	hub_u1_del = udev->parent->bos->ss_cap->bU1devExitLat;
+	hub_u2_del = le16_to_cpu(udev->parent->bos->ss_cap->bU2DevExitLat);
+
+	usb_set_lpm_mel(udev, &udev->u1_params, udev_u1_del,
+			hub, &udev->parent->u1_params, hub_u1_del);
+
+	usb_set_lpm_mel(udev, &udev->u2_params, udev_u2_del,
+			hub, &udev->parent->u2_params, hub_u2_del);
+
+	/*
+	 * Appendix C, section C.2.2.2, says that there is a slight delay from
+	 * when the parent hub notices the downstream port is trying to
+	 * transition to U0 to when the hub initiates a U0 transition on its
+	 * upstream port.  The section says the delays are tPort2PortU1EL and
+	 * tPort2PortU2EL, but it doesn't define what they are.
+	 *
+	 * The hub chapter, sections 10.4.2.4 and 10.4.2.5 seem to be talking
+	 * about the same delays.  Use the maximum delay calculations from those
+	 * sections.  For U1, it's tHubPort2PortExitLat, which is 1us max.  For
+	 * U2, it's tHubPort2PortExitLat + U2DevExitLat - U1DevExitLat.  I
+	 * assume the device exit latencies they are talking about are the hub
+	 * exit latencies.
+	 *
+	 * What do we do if the U2 exit latency is less than the U1 exit
+	 * latency?  It's possible, although not likely...
+	 */
+	port_to_port_delay = 1;
+
+	usb_set_lpm_pel(udev, &udev->u1_params, udev_u1_del,
+			hub, &udev->parent->u1_params, hub_u1_del,
+			port_to_port_delay);
+
+	if (hub_u2_del > hub_u1_del)
+		port_to_port_delay = 1 + hub_u2_del - hub_u1_del;
+	else
+		port_to_port_delay = 1 + hub_u1_del;
+
+	usb_set_lpm_pel(udev, &udev->u2_params, udev_u2_del,
+			hub, &udev->parent->u2_params, hub_u2_del,
+			port_to_port_delay);
+
+	/* Now that we've got PEL, calculate SEL. */
+	usb_set_lpm_sel(udev, &udev->u1_params);
+	usb_set_lpm_sel(udev, &udev->u2_params);
+}
+
+/* USB 2.0 spec Section 11.24.4.5 */
+static int get_hub_descriptor(struct usb_device *hdev, void *data)
+{
+	int i, ret, size;
+	unsigned dtype;
+
+	if (hub_is_superspeed(hdev)) {
+		dtype = USB_DT_SS_HUB;
+		size = USB_DT_SS_HUB_SIZE;
+	} else {
+		dtype = USB_DT_HUB;
+		size = sizeof(struct usb_hub_descriptor);
+	}
+
+	for (i = 0; i < 3; i++) {
+		ret = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
+			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
+			dtype << 8, 0, data, size,
+			USB_CTRL_GET_TIMEOUT);
+		if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2))
+			return ret;
+	}
+	return -EINVAL;
+}
+
+/*
+ * USB 2.0 spec Section 11.24.2.1
+ */
+static int clear_hub_feature(struct usb_device *hdev, int feature)
+{
+	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+		USB_REQ_CLEAR_FEATURE, USB_RT_HUB, feature, 0, NULL, 0, 1000);
+}
+
+/*
+ * USB 2.0 spec Section 11.24.2.2
+ */
+int usb_clear_port_feature(struct usb_device *hdev, int port1, int feature)
+{
+	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+		USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature, port1,
+		NULL, 0, 1000);
+}
+
+/*
+ * USB 2.0 spec Section 11.24.2.13
+ */
+static int set_port_feature(struct usb_device *hdev, int port1, int feature)
+{
+	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+		USB_REQ_SET_FEATURE, USB_RT_PORT, feature, port1,
+		NULL, 0, 1000);
+}
+
+static char *to_led_name(int selector)
+{
+	switch (selector) {
+	case HUB_LED_AMBER:
+		return "amber";
+	case HUB_LED_GREEN:
+		return "green";
+	case HUB_LED_OFF:
+		return "off";
+	case HUB_LED_AUTO:
+		return "auto";
+	default:
+		return "??";
+	}
+}
+
+/*
+ * USB 2.0 spec Section 11.24.2.7.1.10 and table 11-7
+ * for info about using port indicators
+ */
+static void set_port_led(struct usb_hub *hub, int port1, int selector)
+{
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	int status;
+
+	status = set_port_feature(hub->hdev, (selector << 8) | port1,
+			USB_PORT_FEAT_INDICATOR);
+	dev_dbg(&port_dev->dev, "indicator %s status %d\n",
+		to_led_name(selector), status);
+}
+
+#define	LED_CYCLE_PERIOD	((2*HZ)/3)
+
+static void led_work (struct work_struct *work)
+{
+	struct usb_hub		*hub =
+		container_of(work, struct usb_hub, leds.work);
+	struct usb_device	*hdev = hub->hdev;
+	unsigned		i;
+	unsigned		changed = 0;
+	int			cursor = -1;
+
+	if (hdev->state != USB_STATE_CONFIGURED || hub->quiescing)
+		return;
+
+	for (i = 0; i < hdev->maxchild; i++) {
+		unsigned	selector, mode;
+
+		/* 30%-50% duty cycle */
+
+		switch (hub->indicator[i]) {
+		/* cycle marker */
+		case INDICATOR_CYCLE:
+			cursor = i;
+			selector = HUB_LED_AUTO;
+			mode = INDICATOR_AUTO;
+			break;
+		/* blinking green = sw attention */
+		case INDICATOR_GREEN_BLINK:
+			selector = HUB_LED_GREEN;
+			mode = INDICATOR_GREEN_BLINK_OFF;
+			break;
+		case INDICATOR_GREEN_BLINK_OFF:
+			selector = HUB_LED_OFF;
+			mode = INDICATOR_GREEN_BLINK;
+			break;
+		/* blinking amber = hw attention */
+		case INDICATOR_AMBER_BLINK:
+			selector = HUB_LED_AMBER;
+			mode = INDICATOR_AMBER_BLINK_OFF;
+			break;
+		case INDICATOR_AMBER_BLINK_OFF:
+			selector = HUB_LED_OFF;
+			mode = INDICATOR_AMBER_BLINK;
+			break;
+		/* blink green/amber = reserved */
+		case INDICATOR_ALT_BLINK:
+			selector = HUB_LED_GREEN;
+			mode = INDICATOR_ALT_BLINK_OFF;
+			break;
+		case INDICATOR_ALT_BLINK_OFF:
+			selector = HUB_LED_AMBER;
+			mode = INDICATOR_ALT_BLINK;
+			break;
+		default:
+			continue;
+		}
+		if (selector != HUB_LED_AUTO)
+			changed = 1;
+		set_port_led(hub, i + 1, selector);
+		hub->indicator[i] = mode;
+	}
+	if (!changed && blinkenlights) {
+		cursor++;
+		cursor %= hdev->maxchild;
+		set_port_led(hub, cursor + 1, HUB_LED_GREEN);
+		hub->indicator[cursor] = INDICATOR_CYCLE;
+		changed++;
+	}
+	if (changed)
+		queue_delayed_work(system_power_efficient_wq,
+				&hub->leds, LED_CYCLE_PERIOD);
+}
+
+/* use a short timeout for hub/port status fetches */
+#define	USB_STS_TIMEOUT		1000
+#define	USB_STS_RETRIES		5
+
+/*
+ * USB 2.0 spec Section 11.24.2.6
+ */
+static int get_hub_status(struct usb_device *hdev,
+		struct usb_hub_status *data)
+{
+	int i, status = -ETIMEDOUT;
+
+	for (i = 0; i < USB_STS_RETRIES &&
+			(status == -ETIMEDOUT || status == -EPIPE); i++) {
+		status = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
+			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
+			data, sizeof(*data), USB_STS_TIMEOUT);
+	}
+	return status;
+}
+
+/*
+ * USB 2.0 spec Section 11.24.2.7
+ */
+static int get_port_status(struct usb_device *hdev, int port1,
+		struct usb_port_status *data)
+{
+	int i, status = -ETIMEDOUT;
+
+	for (i = 0; i < USB_STS_RETRIES &&
+			(status == -ETIMEDOUT || status == -EPIPE); i++) {
+		status = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
+			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port1,
+			data, sizeof(*data), USB_STS_TIMEOUT);
+	}
+	return status;
+}
+
+static int hub_port_status(struct usb_hub *hub, int port1,
+		u16 *status, u16 *change)
+{
+	int ret;
+
+	mutex_lock(&hub->status_mutex);
+	ret = get_port_status(hub->hdev, port1, &hub->status->port);
+	if (ret < 4) {
+		if (ret != -ENODEV)
+			dev_err(hub->intfdev,
+				"%s failed (err = %d)\n", __func__, ret);
+		if (ret >= 0)
+			ret = -EIO;
+	} else {
+		*status = le16_to_cpu(hub->status->port.wPortStatus);
+		*change = le16_to_cpu(hub->status->port.wPortChange);
+
+		ret = 0;
+	}
+	mutex_unlock(&hub->status_mutex);
+	return ret;
+}
+
+static void kick_hub_wq(struct usb_hub *hub)
+{
+	struct usb_interface *intf;
+
+	if (hub->disconnected || work_pending(&hub->events))
+		return;
+
+	/*
+	 * Suppress autosuspend until the event is proceed.
+	 *
+	 * Be careful and make sure that the symmetric operation is
+	 * always called. We are here only when there is no pending
+	 * work for this hub. Therefore put the interface either when
+	 * the new work is called or when it is canceled.
+	 */
+	intf = to_usb_interface(hub->intfdev);
+	usb_autopm_get_interface_no_resume(intf);
+	kref_get(&hub->kref);
+
+	if (queue_work(hub_wq, &hub->events))
+		return;
+
+	/* the work has already been scheduled */
+	usb_autopm_put_interface_async(intf);
+	kref_put(&hub->kref, hub_release);
+}
+
+void usb_kick_hub_wq(struct usb_device *hdev)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+
+	if (hub)
+		kick_hub_wq(hub);
+}
+
+/*
+ * Let the USB core know that a USB 3.0 device has sent a Function Wake Device
+ * Notification, which indicates it had initiated remote wakeup.
+ *
+ * USB 3.0 hubs do not report the port link state change from U3 to U0 when the
+ * device initiates resume, so the USB core will not receive notice of the
+ * resume through the normal hub interrupt URB.
+ */
+void usb_wakeup_notification(struct usb_device *hdev,
+		unsigned int portnum)
+{
+	struct usb_hub *hub;
+
+	if (!hdev)
+		return;
+
+	hub = usb_hub_to_struct_hub(hdev);
+	if (hub) {
+		set_bit(portnum, hub->wakeup_bits);
+		kick_hub_wq(hub);
+	}
+}
+EXPORT_SYMBOL_GPL(usb_wakeup_notification);
+
+/* completion function, fires on port status changes and various faults */
+static void hub_irq(struct urb *urb)
+{
+	struct usb_hub *hub = urb->context;
+	int status = urb->status;
+	unsigned i;
+	unsigned long bits;
+
+	switch (status) {
+	case -ENOENT:		/* synchronous unlink */
+	case -ECONNRESET:	/* async unlink */
+	case -ESHUTDOWN:	/* hardware going away */
+		return;
+
+	default:		/* presumably an error */
+		/* Cause a hub reset after 10 consecutive errors */
+		dev_dbg (hub->intfdev, "transfer --> %d\n", status);
+		if ((++hub->nerrors < 10) || hub->error)
+			goto resubmit;
+		hub->error = status;
+		/* FALL THROUGH */
+
+	/* let hub_wq handle things */
+	case 0:			/* we got data:  port status changed */
+		bits = 0;
+		for (i = 0; i < urb->actual_length; ++i)
+			bits |= ((unsigned long) ((*hub->buffer)[i]))
+					<< (i*8);
+		hub->event_bits[0] = bits;
+		break;
+	}
+
+	hub->nerrors = 0;
+
+	/* Something happened, let hub_wq figure it out */
+	kick_hub_wq(hub);
+
+resubmit:
+	if (hub->quiescing)
+		return;
+
+	if ((status = usb_submit_urb (hub->urb, GFP_ATOMIC)) != 0
+			&& status != -ENODEV && status != -EPERM)
+		dev_err (hub->intfdev, "resubmit --> %d\n", status);
+}
+
+/* USB 2.0 spec Section 11.24.2.3 */
+static inline int
+hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt)
+{
+	/* Need to clear both directions for control ep */
+	if (((devinfo >> 11) & USB_ENDPOINT_XFERTYPE_MASK) ==
+			USB_ENDPOINT_XFER_CONTROL) {
+		int status = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+				HUB_CLEAR_TT_BUFFER, USB_RT_PORT,
+				devinfo ^ 0x8000, tt, NULL, 0, 1000);
+		if (status)
+			return status;
+	}
+	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+			       HUB_CLEAR_TT_BUFFER, USB_RT_PORT, devinfo,
+			       tt, NULL, 0, 1000);
+}
+
+/*
+ * enumeration blocks hub_wq for a long time. we use keventd instead, since
+ * long blocking there is the exception, not the rule.  accordingly, HCDs
+ * talking to TTs must queue control transfers (not just bulk and iso), so
+ * both can talk to the same hub concurrently.
+ */
+static void hub_tt_work(struct work_struct *work)
+{
+	struct usb_hub		*hub =
+		container_of(work, struct usb_hub, tt.clear_work);
+	unsigned long		flags;
+
+	spin_lock_irqsave (&hub->tt.lock, flags);
+	while (!list_empty(&hub->tt.clear_list)) {
+		struct list_head	*next;
+		struct usb_tt_clear	*clear;
+		struct usb_device	*hdev = hub->hdev;
+		const struct hc_driver	*drv;
+		int			status;
+
+		next = hub->tt.clear_list.next;
+		clear = list_entry (next, struct usb_tt_clear, clear_list);
+		list_del (&clear->clear_list);
+
+		/* drop lock so HCD can concurrently report other TT errors */
+		spin_unlock_irqrestore (&hub->tt.lock, flags);
+		status = hub_clear_tt_buffer (hdev, clear->devinfo, clear->tt);
+		if (status && status != -ENODEV)
+			dev_err (&hdev->dev,
+				"clear tt %d (%04x) error %d\n",
+				clear->tt, clear->devinfo, status);
+
+		/* Tell the HCD, even if the operation failed */
+		drv = clear->hcd->driver;
+		if (drv->clear_tt_buffer_complete)
+			(drv->clear_tt_buffer_complete)(clear->hcd, clear->ep);
+
+		kfree(clear);
+		spin_lock_irqsave(&hub->tt.lock, flags);
+	}
+	spin_unlock_irqrestore (&hub->tt.lock, flags);
+}
+
+/**
+ * usb_hub_set_port_power - control hub port's power state
+ * @hdev: USB device belonging to the usb hub
+ * @hub: target hub
+ * @port1: port index
+ * @set: expected status
+ *
+ * call this function to control port's power via setting or
+ * clearing the port's PORT_POWER feature.
+ *
+ * Return: 0 if successful. A negative error code otherwise.
+ */
+int usb_hub_set_port_power(struct usb_device *hdev, struct usb_hub *hub,
+			   int port1, bool set)
+{
+	int ret;
+
+	if (set)
+		ret = set_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
+	else
+		ret = usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
+
+	if (ret)
+		return ret;
+
+	if (set)
+		set_bit(port1, hub->power_bits);
+	else
+		clear_bit(port1, hub->power_bits);
+	return 0;
+}
+
+/**
+ * usb_hub_clear_tt_buffer - clear control/bulk TT state in high speed hub
+ * @urb: an URB associated with the failed or incomplete split transaction
+ *
+ * High speed HCDs use this to tell the hub driver that some split control or
+ * bulk transaction failed in a way that requires clearing internal state of
+ * a transaction translator.  This is normally detected (and reported) from
+ * interrupt context.
+ *
+ * It may not be possible for that hub to handle additional full (or low)
+ * speed transactions until that state is fully cleared out.
+ *
+ * Return: 0 if successful. A negative error code otherwise.
+ */
+int usb_hub_clear_tt_buffer(struct urb *urb)
+{
+	struct usb_device	*udev = urb->dev;
+	int			pipe = urb->pipe;
+	struct usb_tt		*tt = udev->tt;
+	unsigned long		flags;
+	struct usb_tt_clear	*clear;
+
+	/* we've got to cope with an arbitrary number of pending TT clears,
+	 * since each TT has "at least two" buffers that can need it (and
+	 * there can be many TTs per hub).  even if they're uncommon.
+	 */
+	if ((clear = kmalloc (sizeof *clear, GFP_ATOMIC)) == NULL) {
+		dev_err (&udev->dev, "can't save CLEAR_TT_BUFFER state\n");
+		/* FIXME recover somehow ... RESET_TT? */
+		return -ENOMEM;
+	}
+
+	/* info that CLEAR_TT_BUFFER needs */
+	clear->tt = tt->multi ? udev->ttport : 1;
+	clear->devinfo = usb_pipeendpoint (pipe);
+	clear->devinfo |= udev->devnum << 4;
+	clear->devinfo |= usb_pipecontrol (pipe)
+			? (USB_ENDPOINT_XFER_CONTROL << 11)
+			: (USB_ENDPOINT_XFER_BULK << 11);
+	if (usb_pipein (pipe))
+		clear->devinfo |= 1 << 15;
+
+	/* info for completion callback */
+	clear->hcd = bus_to_hcd(udev->bus);
+	clear->ep = urb->ep;
+
+	/* tell keventd to clear state for this TT */
+	spin_lock_irqsave (&tt->lock, flags);
+	list_add_tail (&clear->clear_list, &tt->clear_list);
+	schedule_work(&tt->clear_work);
+	spin_unlock_irqrestore (&tt->lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_hub_clear_tt_buffer);
+
+static void hub_power_on(struct usb_hub *hub, bool do_delay)
+{
+	int port1;
+
+	/* Enable power on each port.  Some hubs have reserved values
+	 * of LPSM (> 2) in their descriptors, even though they are
+	 * USB 2.0 hubs.  Some hubs do not implement port-power switching
+	 * but only emulate it.  In all cases, the ports won't work
+	 * unless we send these messages to the hub.
+	 */
+	if (hub_is_port_power_switchable(hub))
+		dev_dbg(hub->intfdev, "enabling power on all ports\n");
+	else
+		dev_dbg(hub->intfdev, "trying to enable port power on "
+				"non-switchable hub\n");
+	for (port1 = 1; port1 <= hub->hdev->maxchild; port1++)
+		if (test_bit(port1, hub->power_bits))
+			set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
+		else
+			usb_clear_port_feature(hub->hdev, port1,
+						USB_PORT_FEAT_POWER);
+	if (do_delay)
+		msleep(hub_power_on_good_delay(hub));
+}
+
+static int hub_hub_status(struct usb_hub *hub,
+		u16 *status, u16 *change)
+{
+	int ret;
+
+	mutex_lock(&hub->status_mutex);
+	ret = get_hub_status(hub->hdev, &hub->status->hub);
+	if (ret < 0) {
+		if (ret != -ENODEV)
+			dev_err(hub->intfdev,
+				"%s failed (err = %d)\n", __func__, ret);
+	} else {
+		*status = le16_to_cpu(hub->status->hub.wHubStatus);
+		*change = le16_to_cpu(hub->status->hub.wHubChange);
+		ret = 0;
+	}
+	mutex_unlock(&hub->status_mutex);
+	return ret;
+}
+
+static int hub_set_port_link_state(struct usb_hub *hub, int port1,
+			unsigned int link_status)
+{
+	return set_port_feature(hub->hdev,
+			port1 | (link_status << 3),
+			USB_PORT_FEAT_LINK_STATE);
+}
+
+/*
+ * If USB 3.0 ports are placed into the Disabled state, they will no longer
+ * detect any device connects or disconnects.  This is generally not what the
+ * USB core wants, since it expects a disabled port to produce a port status
+ * change event when a new device connects.
+ *
+ * Instead, set the link state to Disabled, wait for the link to settle into
+ * that state, clear any change bits, and then put the port into the RxDetect
+ * state.
+ */
+static int hub_usb3_port_disable(struct usb_hub *hub, int port1)
+{
+	int ret;
+	int total_time;
+	u16 portchange, portstatus;
+
+	if (!hub_is_superspeed(hub->hdev))
+		return -EINVAL;
+
+	ret = hub_port_status(hub, port1, &portstatus, &portchange);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * USB controller Advanced Micro Devices, Inc. [AMD] FCH USB XHCI
+	 * Controller [1022:7814] will have spurious result making the following
+	 * usb 3.0 device hotplugging route to the 2.0 root hub and recognized
+	 * as high-speed device if we set the usb 3.0 port link state to
+	 * Disabled. Since it's already in USB_SS_PORT_LS_RX_DETECT state, we
+	 * check the state here to avoid the bug.
+	 */
+	if ((portstatus & USB_PORT_STAT_LINK_STATE) ==
+				USB_SS_PORT_LS_RX_DETECT) {
+		dev_dbg(&hub->ports[port1 - 1]->dev,
+			 "Not disabling port; link state is RxDetect\n");
+		return ret;
+	}
+
+	ret = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_SS_DISABLED);
+	if (ret)
+		return ret;
+
+	/* Wait for the link to enter the disabled state. */
+	for (total_time = 0; ; total_time += HUB_DEBOUNCE_STEP) {
+		ret = hub_port_status(hub, port1, &portstatus, &portchange);
+		if (ret < 0)
+			return ret;
+
+		if ((portstatus & USB_PORT_STAT_LINK_STATE) ==
+				USB_SS_PORT_LS_SS_DISABLED)
+			break;
+		if (total_time >= HUB_DEBOUNCE_TIMEOUT)
+			break;
+		msleep(HUB_DEBOUNCE_STEP);
+	}
+	if (total_time >= HUB_DEBOUNCE_TIMEOUT)
+		dev_warn(&hub->ports[port1 - 1]->dev,
+				"Could not disable after %d ms\n", total_time);
+
+	return hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_RX_DETECT);
+}
+
+static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
+{
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	struct usb_device *hdev = hub->hdev;
+	int ret = 0;
+
+	if (port_dev->child && set_state)
+		usb_set_device_state(port_dev->child, USB_STATE_NOTATTACHED);
+	if (!hub->error) {
+		if (hub_is_superspeed(hub->hdev))
+			ret = hub_usb3_port_disable(hub, port1);
+		else
+			ret = usb_clear_port_feature(hdev, port1,
+					USB_PORT_FEAT_ENABLE);
+	}
+	if (ret && ret != -ENODEV)
+		dev_err(&port_dev->dev, "cannot disable (err = %d)\n", ret);
+	return ret;
+}
+
+/*
+ * Disable a port and mark a logical connect-change event, so that some
+ * time later hub_wq will disconnect() any existing usb_device on the port
+ * and will re-enumerate if there actually is a device attached.
+ */
+static void hub_port_logical_disconnect(struct usb_hub *hub, int port1)
+{
+	dev_dbg(&hub->ports[port1 - 1]->dev, "logical disconnect\n");
+	hub_port_disable(hub, port1, 1);
+
+	/* FIXME let caller ask to power down the port:
+	 *  - some devices won't enumerate without a VBUS power cycle
+	 *  - SRP saves power that way
+	 *  - ... new call, TBD ...
+	 * That's easy if this hub can switch power per-port, and
+	 * hub_wq reactivates the port later (timer, SRP, etc).
+	 * Powerdown must be optional, because of reset/DFU.
+	 */
+
+	set_bit(port1, hub->change_bits);
+	kick_hub_wq(hub);
+}
+
+/**
+ * usb_remove_device - disable a device's port on its parent hub
+ * @udev: device to be disabled and removed
+ * Context: @udev locked, must be able to sleep.
+ *
+ * After @udev's port has been disabled, hub_wq is notified and it will
+ * see that the device has been disconnected.  When the device is
+ * physically unplugged and something is plugged in, the events will
+ * be received and processed normally.
+ *
+ * Return: 0 if successful. A negative error code otherwise.
+ */
+int usb_remove_device(struct usb_device *udev)
+{
+	struct usb_hub *hub;
+	struct usb_interface *intf;
+
+	if (!udev->parent)	/* Can't remove a root hub */
+		return -EINVAL;
+	hub = usb_hub_to_struct_hub(udev->parent);
+	intf = to_usb_interface(hub->intfdev);
+
+	usb_autopm_get_interface(intf);
+	set_bit(udev->portnum, hub->removed_bits);
+	hub_port_logical_disconnect(hub, udev->portnum);
+	usb_autopm_put_interface(intf);
+	return 0;
+}
+
+enum hub_activation_type {
+	HUB_INIT, HUB_INIT2, HUB_INIT3,		/* INITs must come first */
+	HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME,
+};
+
+static void hub_init_func2(struct work_struct *ws);
+static void hub_init_func3(struct work_struct *ws);
+
+static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
+{
+	struct usb_device *hdev = hub->hdev;
+	struct usb_hcd *hcd;
+	int ret;
+	int port1;
+	int status;
+	bool need_debounce_delay = false;
+	unsigned delay;
+
+	/* Continue a partial initialization */
+	if (type == HUB_INIT2)
+		goto init2;
+	if (type == HUB_INIT3)
+		goto init3;
+
+	/* The superspeed hub except for root hub has to use Hub Depth
+	 * value as an offset into the route string to locate the bits
+	 * it uses to determine the downstream port number. So hub driver
+	 * should send a set hub depth request to superspeed hub after
+	 * the superspeed hub is set configuration in initialization or
+	 * reset procedure.
+	 *
+	 * After a resume, port power should still be on.
+	 * For any other type of activation, turn it on.
+	 */
+	if (type != HUB_RESUME) {
+		if (hdev->parent && hub_is_superspeed(hdev)) {
+			ret = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+					HUB_SET_DEPTH, USB_RT_HUB,
+					hdev->level - 1, 0, NULL, 0,
+					USB_CTRL_SET_TIMEOUT);
+			if (ret < 0)
+				dev_err(hub->intfdev,
+						"set hub depth failed\n");
+		}
+
+		/* Speed up system boot by using a delayed_work for the
+		 * hub's initial power-up delays.  This is pretty awkward
+		 * and the implementation looks like a home-brewed sort of
+		 * setjmp/longjmp, but it saves at least 100 ms for each
+		 * root hub (assuming usbcore is compiled into the kernel
+		 * rather than as a module).  It adds up.
+		 *
+		 * This can't be done for HUB_RESUME or HUB_RESET_RESUME
+		 * because for those activation types the ports have to be
+		 * operational when we return.  In theory this could be done
+		 * for HUB_POST_RESET, but it's easier not to.
+		 */
+		if (type == HUB_INIT) {
+			unsigned delay = hub_power_on_good_delay(hub);
+
+			hub_power_on(hub, false);
+			INIT_DELAYED_WORK(&hub->init_work, hub_init_func2);
+			queue_delayed_work(system_power_efficient_wq,
+					&hub->init_work,
+					msecs_to_jiffies(delay));
+
+			/* Suppress autosuspend until init is done */
+			usb_autopm_get_interface_no_resume(
+					to_usb_interface(hub->intfdev));
+			return;		/* Continues at init2: below */
+		} else if (type == HUB_RESET_RESUME) {
+			/* The internal host controller state for the hub device
+			 * may be gone after a host power loss on system resume.
+			 * Update the device's info so the HW knows it's a hub.
+			 */
+			hcd = bus_to_hcd(hdev->bus);
+			if (hcd->driver->update_hub_device) {
+				ret = hcd->driver->update_hub_device(hcd, hdev,
+						&hub->tt, GFP_NOIO);
+				if (ret < 0) {
+					dev_err(hub->intfdev, "Host not "
+							"accepting hub info "
+							"update.\n");
+					dev_err(hub->intfdev, "LS/FS devices "
+							"and hubs may not work "
+							"under this hub\n.");
+				}
+			}
+			hub_power_on(hub, true);
+		} else {
+			hub_power_on(hub, true);
+		}
+	}
+ init2:
+
+	/*
+	 * Check each port and set hub->change_bits to let hub_wq know
+	 * which ports need attention.
+	 */
+	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
+		struct usb_port *port_dev = hub->ports[port1 - 1];
+		struct usb_device *udev = port_dev->child;
+		u16 portstatus, portchange;
+
+		portstatus = portchange = 0;
+		status = hub_port_status(hub, port1, &portstatus, &portchange);
+		if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
+			dev_dbg(&port_dev->dev, "status %04x change %04x\n",
+					portstatus, portchange);
+
+		/*
+		 * After anything other than HUB_RESUME (i.e., initialization
+		 * or any sort of reset), every port should be disabled.
+		 * Unconnected ports should likewise be disabled (paranoia),
+		 * and so should ports for which we have no usb_device.
+		 */
+		if ((portstatus & USB_PORT_STAT_ENABLE) && (
+				type != HUB_RESUME ||
+				!(portstatus & USB_PORT_STAT_CONNECTION) ||
+				!udev ||
+				udev->state == USB_STATE_NOTATTACHED)) {
+			/*
+			 * USB3 protocol ports will automatically transition
+			 * to Enabled state when detect an USB3.0 device attach.
+			 * Do not disable USB3 protocol ports, just pretend
+			 * power was lost
+			 */
+			portstatus &= ~USB_PORT_STAT_ENABLE;
+			if (!hub_is_superspeed(hdev))
+				usb_clear_port_feature(hdev, port1,
+						   USB_PORT_FEAT_ENABLE);
+		}
+
+		/* Clear status-change flags; we'll debounce later */
+		if (portchange & USB_PORT_STAT_C_CONNECTION) {
+			need_debounce_delay = true;
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_CONNECTION);
+		}
+		if (portchange & USB_PORT_STAT_C_ENABLE) {
+			need_debounce_delay = true;
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_ENABLE);
+		}
+		if (portchange & USB_PORT_STAT_C_RESET) {
+			need_debounce_delay = true;
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_RESET);
+		}
+		if ((portchange & USB_PORT_STAT_C_BH_RESET) &&
+				hub_is_superspeed(hub->hdev)) {
+			need_debounce_delay = true;
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_BH_PORT_RESET);
+		}
+		/* We can forget about a "removed" device when there's a
+		 * physical disconnect or the connect status changes.
+		 */
+		if (!(portstatus & USB_PORT_STAT_CONNECTION) ||
+				(portchange & USB_PORT_STAT_C_CONNECTION))
+			clear_bit(port1, hub->removed_bits);
+
+		if (!udev || udev->state == USB_STATE_NOTATTACHED) {
+			/* Tell hub_wq to disconnect the device or
+			 * check for a new connection
+			 */
+			if (udev || (portstatus & USB_PORT_STAT_CONNECTION) ||
+			    (portstatus & USB_PORT_STAT_OVERCURRENT))
+				set_bit(port1, hub->change_bits);
+
+		} else if (portstatus & USB_PORT_STAT_ENABLE) {
+			bool port_resumed = (portstatus &
+					USB_PORT_STAT_LINK_STATE) ==
+				USB_SS_PORT_LS_U0;
+			/* The power session apparently survived the resume.
+			 * If there was an overcurrent or suspend change
+			 * (i.e., remote wakeup request), have hub_wq
+			 * take care of it.  Look at the port link state
+			 * for USB 3.0 hubs, since they don't have a suspend
+			 * change bit, and they don't set the port link change
+			 * bit on device-initiated resume.
+			 */
+			if (portchange || (hub_is_superspeed(hub->hdev) &&
+						port_resumed))
+				set_bit(port1, hub->change_bits);
+
+		} else if (udev->persist_enabled) {
+#ifdef CONFIG_PM
+			udev->reset_resume = 1;
+#endif
+			/* Don't set the change_bits when the device
+			 * was powered off.
+			 */
+			if (test_bit(port1, hub->power_bits))
+				set_bit(port1, hub->change_bits);
+
+		} else {
+			/* The power session is gone; tell hub_wq */
+			usb_set_device_state(udev, USB_STATE_NOTATTACHED);
+			set_bit(port1, hub->change_bits);
+		}
+	}
+
+	/* If no port-status-change flags were set, we don't need any
+	 * debouncing.  If flags were set we can try to debounce the
+	 * ports all at once right now, instead of letting hub_wq do them
+	 * one at a time later on.
+	 *
+	 * If any port-status changes do occur during this delay, hub_wq
+	 * will see them later and handle them normally.
+	 */
+	if (need_debounce_delay) {
+		delay = HUB_DEBOUNCE_STABLE;
+
+		/* Don't do a long sleep inside a workqueue routine */
+		if (type == HUB_INIT2) {
+			INIT_DELAYED_WORK(&hub->init_work, hub_init_func3);
+			queue_delayed_work(system_power_efficient_wq,
+					&hub->init_work,
+					msecs_to_jiffies(delay));
+			return;		/* Continues at init3: below */
+		} else {
+			msleep(delay);
+		}
+	}
+ init3:
+	hub->quiescing = 0;
+
+	status = usb_submit_urb(hub->urb, GFP_NOIO);
+	if (status < 0)
+		dev_err(hub->intfdev, "activate --> %d\n", status);
+	if (hub->has_indicators && blinkenlights)
+		queue_delayed_work(system_power_efficient_wq,
+				&hub->leds, LED_CYCLE_PERIOD);
+
+	/* Scan all ports that need attention */
+	kick_hub_wq(hub);
+
+	/* Allow autosuspend if it was suppressed */
+	if (type <= HUB_INIT3)
+		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
+}
+
+/* Implement the continuations for the delays above */
+static void hub_init_func2(struct work_struct *ws)
+{
+	struct usb_hub *hub = container_of(ws, struct usb_hub, init_work.work);
+
+	hub_activate(hub, HUB_INIT2);
+}
+
+static void hub_init_func3(struct work_struct *ws)
+{
+	struct usb_hub *hub = container_of(ws, struct usb_hub, init_work.work);
+
+	hub_activate(hub, HUB_INIT3);
+}
+
+enum hub_quiescing_type {
+	HUB_DISCONNECT, HUB_PRE_RESET, HUB_SUSPEND
+};
+
+static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type)
+{
+	struct usb_device *hdev = hub->hdev;
+	int i;
+
+	cancel_delayed_work_sync(&hub->init_work);
+
+	/* hub_wq and related activity won't re-trigger */
+	hub->quiescing = 1;
+
+	if (type != HUB_SUSPEND) {
+		/* Disconnect all the children */
+		for (i = 0; i < hdev->maxchild; ++i) {
+			if (hub->ports[i]->child)
+				usb_disconnect(&hub->ports[i]->child);
+		}
+	}
+
+	/* Stop hub_wq and related activity */
+	usb_kill_urb(hub->urb);
+	if (hub->has_indicators)
+		cancel_delayed_work_sync(&hub->leds);
+	if (hub->tt.hub)
+		flush_work(&hub->tt.clear_work);
+}
+
+static void hub_pm_barrier_for_all_ports(struct usb_hub *hub)
+{
+	int i;
+
+	for (i = 0; i < hub->hdev->maxchild; ++i)
+		pm_runtime_barrier(&hub->ports[i]->dev);
+}
+
+/* caller has locked the hub device */
+static int hub_pre_reset(struct usb_interface *intf)
+{
+	struct usb_hub *hub = usb_get_intfdata(intf);
+
+	hub_quiesce(hub, HUB_PRE_RESET);
+	hub->in_reset = 1;
+	hub_pm_barrier_for_all_ports(hub);
+	return 0;
+}
+
+/* caller has locked the hub device */
+static int hub_post_reset(struct usb_interface *intf)
+{
+	struct usb_hub *hub = usb_get_intfdata(intf);
+
+	hub->in_reset = 0;
+	hub_pm_barrier_for_all_ports(hub);
+	hub_activate(hub, HUB_POST_RESET);
+	return 0;
+}
+
+static int hub_configure(struct usb_hub *hub,
+	struct usb_endpoint_descriptor *endpoint)
+{
+	struct usb_hcd *hcd;
+	struct usb_device *hdev = hub->hdev;
+	struct device *hub_dev = hub->intfdev;
+	u16 hubstatus, hubchange;
+	u16 wHubCharacteristics;
+	unsigned int pipe;
+	int maxp, ret, i;
+	char *message = "out of memory";
+	unsigned unit_load;
+	unsigned full_load;
+	unsigned maxchild;
+
+	hub->buffer = kmalloc(sizeof(*hub->buffer), GFP_KERNEL);
+	if (!hub->buffer) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	hub->status = kmalloc(sizeof(*hub->status), GFP_KERNEL);
+	if (!hub->status) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	mutex_init(&hub->status_mutex);
+
+	hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL);
+	if (!hub->descriptor) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* Request the entire hub descriptor.
+	 * hub->descriptor can handle USB_MAXCHILDREN ports,
+	 * but the hub can/will return fewer bytes here.
+	 */
+	ret = get_hub_descriptor(hdev, hub->descriptor);
+	if (ret < 0) {
+		message = "can't read hub descriptor";
+		goto fail;
+	} else if (hub->descriptor->bNbrPorts > USB_MAXCHILDREN) {
+		message = "hub has too many ports!";
+		ret = -ENODEV;
+		goto fail;
+	} else if (hub->descriptor->bNbrPorts == 0) {
+		message = "hub doesn't have any ports!";
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	maxchild = hub->descriptor->bNbrPorts;
+	dev_info(hub_dev, "%d port%s detected\n", maxchild,
+			(maxchild == 1) ? "" : "s");
+
+	hub->ports = kzalloc(maxchild * sizeof(struct usb_port *), GFP_KERNEL);
+	if (!hub->ports) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
+	if (hub_is_superspeed(hdev)) {
+		unit_load = 150;
+		full_load = 900;
+	} else {
+		unit_load = 100;
+		full_load = 500;
+	}
+
+	/* FIXME for USB 3.0, skip for now */
+	if ((wHubCharacteristics & HUB_CHAR_COMPOUND) &&
+			!(hub_is_superspeed(hdev))) {
+		int	i;
+		char	portstr[USB_MAXCHILDREN + 1];
+
+		for (i = 0; i < maxchild; i++)
+			portstr[i] = hub->descriptor->u.hs.DeviceRemovable
+				    [((i + 1) / 8)] & (1 << ((i + 1) % 8))
+				? 'F' : 'R';
+		portstr[maxchild] = 0;
+		dev_dbg(hub_dev, "compound device; port removable status: %s\n", portstr);
+	} else
+		dev_dbg(hub_dev, "standalone hub\n");
+
+	switch (wHubCharacteristics & HUB_CHAR_LPSM) {
+	case HUB_CHAR_COMMON_LPSM:
+		dev_dbg(hub_dev, "ganged power switching\n");
+		break;
+	case HUB_CHAR_INDV_PORT_LPSM:
+		dev_dbg(hub_dev, "individual port power switching\n");
+		break;
+	case HUB_CHAR_NO_LPSM:
+	case HUB_CHAR_LPSM:
+		dev_dbg(hub_dev, "no power switching (usb 1.0)\n");
+		break;
+	}
+
+	switch (wHubCharacteristics & HUB_CHAR_OCPM) {
+	case HUB_CHAR_COMMON_OCPM:
+		dev_dbg(hub_dev, "global over-current protection\n");
+		break;
+	case HUB_CHAR_INDV_PORT_OCPM:
+		dev_dbg(hub_dev, "individual port over-current protection\n");
+		break;
+	case HUB_CHAR_NO_OCPM:
+	case HUB_CHAR_OCPM:
+		dev_dbg(hub_dev, "no over-current protection\n");
+		break;
+	}
+
+	spin_lock_init (&hub->tt.lock);
+	INIT_LIST_HEAD (&hub->tt.clear_list);
+	INIT_WORK(&hub->tt.clear_work, hub_tt_work);
+	switch (hdev->descriptor.bDeviceProtocol) {
+	case USB_HUB_PR_FS:
+		break;
+	case USB_HUB_PR_HS_SINGLE_TT:
+		dev_dbg(hub_dev, "Single TT\n");
+		hub->tt.hub = hdev;
+		break;
+	case USB_HUB_PR_HS_MULTI_TT:
+		ret = usb_set_interface(hdev, 0, 1);
+		if (ret == 0) {
+			dev_dbg(hub_dev, "TT per port\n");
+			hub->tt.multi = 1;
+		} else
+			dev_err(hub_dev, "Using single TT (err %d)\n",
+				ret);
+		hub->tt.hub = hdev;
+		break;
+	case USB_HUB_PR_SS:
+		/* USB 3.0 hubs don't have a TT */
+		break;
+	default:
+		dev_dbg(hub_dev, "Unrecognized hub protocol %d\n",
+			hdev->descriptor.bDeviceProtocol);
+		break;
+	}
+
+	/* Note 8 FS bit times == (8 bits / 12000000 bps) ~= 666ns */
+	switch (wHubCharacteristics & HUB_CHAR_TTTT) {
+	case HUB_TTTT_8_BITS:
+		if (hdev->descriptor.bDeviceProtocol != 0) {
+			hub->tt.think_time = 666;
+			dev_dbg(hub_dev, "TT requires at most %d "
+					"FS bit times (%d ns)\n",
+				8, hub->tt.think_time);
+		}
+		break;
+	case HUB_TTTT_16_BITS:
+		hub->tt.think_time = 666 * 2;
+		dev_dbg(hub_dev, "TT requires at most %d "
+				"FS bit times (%d ns)\n",
+			16, hub->tt.think_time);
+		break;
+	case HUB_TTTT_24_BITS:
+		hub->tt.think_time = 666 * 3;
+		dev_dbg(hub_dev, "TT requires at most %d "
+				"FS bit times (%d ns)\n",
+			24, hub->tt.think_time);
+		break;
+	case HUB_TTTT_32_BITS:
+		hub->tt.think_time = 666 * 4;
+		dev_dbg(hub_dev, "TT requires at most %d "
+				"FS bit times (%d ns)\n",
+			32, hub->tt.think_time);
+		break;
+	}
+
+	/* probe() zeroes hub->indicator[] */
+	if (wHubCharacteristics & HUB_CHAR_PORTIND) {
+		hub->has_indicators = 1;
+		dev_dbg(hub_dev, "Port indicators are supported\n");
+	}
+
+	dev_dbg(hub_dev, "power on to power good time: %dms\n",
+		hub->descriptor->bPwrOn2PwrGood * 2);
+
+	/* power budgeting mostly matters with bus-powered hubs,
+	 * and battery-powered root hubs (may provide just 8 mA).
+	 */
+	ret = usb_get_status(hdev, USB_RECIP_DEVICE, 0, &hubstatus);
+	if (ret) {
+		message = "can't get hub status";
+		goto fail;
+	}
+	hcd = bus_to_hcd(hdev->bus);
+	if (hdev == hdev->bus->root_hub) {
+		if (hcd->power_budget > 0)
+			hdev->bus_mA = hcd->power_budget;
+		else
+			hdev->bus_mA = full_load * maxchild;
+		if (hdev->bus_mA >= full_load)
+			hub->mA_per_port = full_load;
+		else {
+			hub->mA_per_port = hdev->bus_mA;
+			hub->limited_power = 1;
+		}
+	} else if ((hubstatus & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
+		int remaining = hdev->bus_mA -
+			hub->descriptor->bHubContrCurrent;
+
+		dev_dbg(hub_dev, "hub controller current requirement: %dmA\n",
+			hub->descriptor->bHubContrCurrent);
+		hub->limited_power = 1;
+
+		if (remaining < maxchild * unit_load)
+			dev_warn(hub_dev,
+					"insufficient power available "
+					"to use all downstream ports\n");
+		hub->mA_per_port = unit_load;	/* 7.2.1 */
+
+	} else {	/* Self-powered external hub */
+		/* FIXME: What about battery-powered external hubs that
+		 * provide less current per port? */
+		hub->mA_per_port = full_load;
+	}
+	if (hub->mA_per_port < full_load)
+		dev_dbg(hub_dev, "%umA bus power budget for each child\n",
+				hub->mA_per_port);
+
+	ret = hub_hub_status(hub, &hubstatus, &hubchange);
+	if (ret < 0) {
+		message = "can't get hub status";
+		goto fail;
+	}
+
+	/* local power status reports aren't always correct */
+	if (hdev->actconfig->desc.bmAttributes & USB_CONFIG_ATT_SELFPOWER)
+		dev_dbg(hub_dev, "local power source is %s\n",
+			(hubstatus & HUB_STATUS_LOCAL_POWER)
+			? "lost (inactive)" : "good");
+
+	if ((wHubCharacteristics & HUB_CHAR_OCPM) == 0)
+		dev_dbg(hub_dev, "%sover-current condition exists\n",
+			(hubstatus & HUB_STATUS_OVERCURRENT) ? "" : "no ");
+
+	/* set up the interrupt endpoint
+	 * We use the EP's maxpacket size instead of (PORTS+1+7)/8
+	 * bytes as USB2.0[11.12.3] says because some hubs are known
+	 * to send more data (and thus cause overflow). For root hubs,
+	 * maxpktsize is defined in hcd.c's fake endpoint descriptors
+	 * to be big enough for at least USB_MAXCHILDREN ports. */
+	pipe = usb_rcvintpipe(hdev, endpoint->bEndpointAddress);
+	maxp = usb_maxpacket(hdev, pipe, usb_pipeout(pipe));
+
+	if (maxp > sizeof(*hub->buffer))
+		maxp = sizeof(*hub->buffer);
+
+	hub->urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!hub->urb) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	usb_fill_int_urb(hub->urb, hdev, pipe, *hub->buffer, maxp, hub_irq,
+		hub, endpoint->bInterval);
+
+	/* maybe cycle the hub leds */
+	if (hub->has_indicators && blinkenlights)
+		hub->indicator[0] = INDICATOR_CYCLE;
+
+	mutex_lock(&usb_port_peer_mutex);
+	for (i = 0; i < maxchild; i++) {
+		ret = usb_hub_create_port_device(hub, i + 1);
+		if (ret < 0) {
+			dev_err(hub->intfdev,
+				"couldn't create port%d device.\n", i + 1);
+			break;
+		}
+	}
+	hdev->maxchild = i;
+	for (i = 0; i < hdev->maxchild; i++) {
+		struct usb_port *port_dev = hub->ports[i];
+
+		pm_runtime_put(&port_dev->dev);
+	}
+
+	mutex_unlock(&usb_port_peer_mutex);
+	if (ret < 0)
+		goto fail;
+
+	/* Update the HCD's internal representation of this hub before hub_wq
+	 * starts getting port status changes for devices under the hub.
+	 */
+	if (hcd->driver->update_hub_device) {
+		ret = hcd->driver->update_hub_device(hcd, hdev,
+				&hub->tt, GFP_KERNEL);
+		if (ret < 0) {
+			message = "can't update HCD hub info";
+			goto fail;
+		}
+	}
+
+	usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
+
+	hub_activate(hub, HUB_INIT);
+	return 0;
+
+fail:
+	dev_err (hub_dev, "config failed, %s (err %d)\n",
+			message, ret);
+	/* hub_disconnect() frees urb and descriptor */
+	return ret;
+}
+
+static void hub_release(struct kref *kref)
+{
+	struct usb_hub *hub = container_of(kref, struct usb_hub, kref);
+
+	usb_put_dev(hub->hdev);
+	usb_put_intf(to_usb_interface(hub->intfdev));
+	kfree(hub);
+}
+
+static unsigned highspeed_hubs;
+
+static void hub_disconnect(struct usb_interface *intf)
+{
+	struct usb_hub *hub = usb_get_intfdata(intf);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	int port1;
+
+	/*
+	 * Stop adding new hub events. We do not want to block here and thus
+	 * will not try to remove any pending work item.
+	 */
+	hub->disconnected = 1;
+
+	/* Disconnect all children and quiesce the hub */
+	hub->error = 0;
+	hub_quiesce(hub, HUB_DISCONNECT);
+
+	mutex_lock(&usb_port_peer_mutex);
+
+	/* Avoid races with recursively_mark_NOTATTACHED() */
+	spin_lock_irq(&device_state_lock);
+	port1 = hdev->maxchild;
+	hdev->maxchild = 0;
+	usb_set_intfdata(intf, NULL);
+	spin_unlock_irq(&device_state_lock);
+
+	for (; port1 > 0; --port1)
+		usb_hub_remove_port_device(hub, port1);
+
+	mutex_unlock(&usb_port_peer_mutex);
+
+	if (hub->hdev->speed == USB_SPEED_HIGH)
+		highspeed_hubs--;
+
+	usb_free_urb(hub->urb);
+	kfree(hub->ports);
+	kfree(hub->descriptor);
+	kfree(hub->status);
+	kfree(hub->buffer);
+
+	pm_suspend_ignore_children(&intf->dev, false);
+	kref_put(&hub->kref, hub_release);
+}
+
+static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	struct usb_host_interface *desc;
+	struct usb_endpoint_descriptor *endpoint;
+	struct usb_device *hdev;
+	struct usb_hub *hub;
+
+	desc = intf->cur_altsetting;
+	hdev = interface_to_usbdev(intf);
+
+	/*
+	 * Set default autosuspend delay as 0 to speedup bus suspend,
+	 * based on the below considerations:
+	 *
+	 * - Unlike other drivers, the hub driver does not rely on the
+	 *   autosuspend delay to provide enough time to handle a wakeup
+	 *   event, and the submitted status URB is just to check future
+	 *   change on hub downstream ports, so it is safe to do it.
+	 *
+	 * - The patch might cause one or more auto supend/resume for
+	 *   below very rare devices when they are plugged into hub
+	 *   first time:
+	 *
+	 *   	devices having trouble initializing, and disconnect
+	 *   	themselves from the bus and then reconnect a second
+	 *   	or so later
+	 *
+	 *   	devices just for downloading firmware, and disconnects
+	 *   	themselves after completing it
+	 *
+	 *   For these quite rare devices, their drivers may change the
+	 *   autosuspend delay of their parent hub in the probe() to one
+	 *   appropriate value to avoid the subtle problem if someone
+	 *   does care it.
+	 *
+	 * - The patch may cause one or more auto suspend/resume on
+	 *   hub during running 'lsusb', but it is probably too
+	 *   infrequent to worry about.
+	 *
+	 * - Change autosuspend delay of hub can avoid unnecessary auto
+	 *   suspend timer for hub, also may decrease power consumption
+	 *   of USB bus.
+	 *
+	 * - If user has indicated to prevent autosuspend by passing
+	 *   usbcore.autosuspend = -1 then keep autosuspend disabled.
+	 */
+#ifdef CONFIG_PM
+	if (hdev->dev.power.autosuspend_delay >= 0)
+		pm_runtime_set_autosuspend_delay(&hdev->dev, 0);
+#endif
+
+	/*
+	 * Hubs have proper suspend/resume support, except for root hubs
+	 * where the controller driver doesn't have bus_suspend and
+	 * bus_resume methods.
+	 */
+	if (hdev->parent) {		/* normal device */
+		usb_enable_autosuspend(hdev);
+	} else {			/* root hub */
+		const struct hc_driver *drv = bus_to_hcd(hdev->bus)->driver;
+
+		if (drv->bus_suspend && drv->bus_resume)
+			usb_enable_autosuspend(hdev);
+	}
+
+	if (hdev->level == MAX_TOPO_LEVEL) {
+		dev_err(&intf->dev,
+			"Unsupported bus topology: hub nested too deep\n");
+		return -E2BIG;
+	}
+
+#ifdef	CONFIG_USB_OTG_BLACKLIST_HUB
+	if (hdev->parent) {
+		dev_warn(&intf->dev, "ignoring external hub\n");
+		return -ENODEV;
+	}
+#endif
+
+	/* Some hubs have a subclass of 1, which AFAICT according to the */
+	/*  specs is not defined, but it works */
+	if ((desc->desc.bInterfaceSubClass != 0) &&
+	    (desc->desc.bInterfaceSubClass != 1)) {
+descriptor_error:
+		dev_err (&intf->dev, "bad descriptor, ignoring hub\n");
+		return -EIO;
+	}
+
+	/* Multiple endpoints? What kind of mutant ninja-hub is this? */
+	if (desc->desc.bNumEndpoints != 1)
+		goto descriptor_error;
+
+	endpoint = &desc->endpoint[0].desc;
+
+	/* If it's not an interrupt in endpoint, we'd better punt! */
+	if (!usb_endpoint_is_int_in(endpoint))
+		goto descriptor_error;
+
+	/* We found a hub */
+	dev_info (&intf->dev, "USB hub found\n");
+
+	hub = kzalloc(sizeof(*hub), GFP_KERNEL);
+	if (!hub) {
+		dev_dbg (&intf->dev, "couldn't kmalloc hub struct\n");
+		return -ENOMEM;
+	}
+
+	kref_init(&hub->kref);
+	hub->intfdev = &intf->dev;
+	hub->hdev = hdev;
+	INIT_DELAYED_WORK(&hub->leds, led_work);
+	INIT_DELAYED_WORK(&hub->init_work, NULL);
+	INIT_WORK(&hub->events, hub_event);
+	usb_get_intf(intf);
+	usb_get_dev(hdev);
+
+	usb_set_intfdata (intf, hub);
+	intf->needs_remote_wakeup = 1;
+	pm_suspend_ignore_children(&intf->dev, true);
+
+	if (hdev->speed == USB_SPEED_HIGH)
+		highspeed_hubs++;
+
+	if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND)
+		hub->quirk_check_port_auto_suspend = 1;
+
+	if (hub_configure(hub, endpoint) >= 0)
+		return 0;
+
+	hub_disconnect (intf);
+	return -ENODEV;
+}
+
+static int
+hub_ioctl(struct usb_interface *intf, unsigned int code, void *user_data)
+{
+	struct usb_device *hdev = interface_to_usbdev (intf);
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+
+	/* assert ifno == 0 (part of hub spec) */
+	switch (code) {
+	case USBDEVFS_HUB_PORTINFO: {
+		struct usbdevfs_hub_portinfo *info = user_data;
+		int i;
+
+		spin_lock_irq(&device_state_lock);
+		if (hdev->devnum <= 0)
+			info->nports = 0;
+		else {
+			info->nports = hdev->maxchild;
+			for (i = 0; i < info->nports; i++) {
+				if (hub->ports[i]->child == NULL)
+					info->port[i] = 0;
+				else
+					info->port[i] =
+						hub->ports[i]->child->devnum;
+			}
+		}
+		spin_unlock_irq(&device_state_lock);
+
+		return info->nports + 1;
+		}
+
+	default:
+		return -ENOSYS;
+	}
+}
+
+/*
+ * Allow user programs to claim ports on a hub.  When a device is attached
+ * to one of these "claimed" ports, the program will "own" the device.
+ */
+static int find_port_owner(struct usb_device *hdev, unsigned port1,
+		struct usb_dev_state ***ppowner)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+
+	if (hdev->state == USB_STATE_NOTATTACHED)
+		return -ENODEV;
+	if (port1 == 0 || port1 > hdev->maxchild)
+		return -EINVAL;
+
+	/* Devices not managed by the hub driver
+	 * will always have maxchild equal to 0.
+	 */
+	*ppowner = &(hub->ports[port1 - 1]->port_owner);
+	return 0;
+}
+
+/* In the following three functions, the caller must hold hdev's lock */
+int usb_hub_claim_port(struct usb_device *hdev, unsigned port1,
+		       struct usb_dev_state *owner)
+{
+	int rc;
+	struct usb_dev_state **powner;
+
+	rc = find_port_owner(hdev, port1, &powner);
+	if (rc)
+		return rc;
+	if (*powner)
+		return -EBUSY;
+	*powner = owner;
+	return rc;
+}
+EXPORT_SYMBOL_GPL(usb_hub_claim_port);
+
+int usb_hub_release_port(struct usb_device *hdev, unsigned port1,
+			 struct usb_dev_state *owner)
+{
+	int rc;
+	struct usb_dev_state **powner;
+
+	rc = find_port_owner(hdev, port1, &powner);
+	if (rc)
+		return rc;
+	if (*powner != owner)
+		return -ENOENT;
+	*powner = NULL;
+	return rc;
+}
+EXPORT_SYMBOL_GPL(usb_hub_release_port);
+
+void usb_hub_release_all_ports(struct usb_device *hdev, struct usb_dev_state *owner)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+	int n;
+
+	for (n = 0; n < hdev->maxchild; n++) {
+		if (hub->ports[n]->port_owner == owner)
+			hub->ports[n]->port_owner = NULL;
+	}
+
+}
+
+/* The caller must hold udev's lock */
+bool usb_device_is_owned(struct usb_device *udev)
+{
+	struct usb_hub *hub;
+
+	if (udev->state == USB_STATE_NOTATTACHED || !udev->parent)
+		return false;
+	hub = usb_hub_to_struct_hub(udev->parent);
+	return !!hub->ports[udev->portnum - 1]->port_owner;
+}
+
+static void recursively_mark_NOTATTACHED(struct usb_device *udev)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(udev);
+	int i;
+
+	for (i = 0; i < udev->maxchild; ++i) {
+		if (hub->ports[i]->child)
+			recursively_mark_NOTATTACHED(hub->ports[i]->child);
+	}
+	if (udev->state == USB_STATE_SUSPENDED)
+		udev->active_duration -= jiffies;
+	udev->state = USB_STATE_NOTATTACHED;
+}
+
+/**
+ * usb_set_device_state - change a device's current state (usbcore, hcds)
+ * @udev: pointer to device whose state should be changed
+ * @new_state: new state value to be stored
+ *
+ * udev->state is _not_ fully protected by the device lock.  Although
+ * most transitions are made only while holding the lock, the state can
+ * can change to USB_STATE_NOTATTACHED at almost any time.  This
+ * is so that devices can be marked as disconnected as soon as possible,
+ * without having to wait for any semaphores to be released.  As a result,
+ * all changes to any device's state must be protected by the
+ * device_state_lock spinlock.
+ *
+ * Once a device has been added to the device tree, all changes to its state
+ * should be made using this routine.  The state should _not_ be set directly.
+ *
+ * If udev->state is already USB_STATE_NOTATTACHED then no change is made.
+ * Otherwise udev->state is set to new_state, and if new_state is
+ * USB_STATE_NOTATTACHED then all of udev's descendants' states are also set
+ * to USB_STATE_NOTATTACHED.
+ */
+void usb_set_device_state(struct usb_device *udev,
+		enum usb_device_state new_state)
+{
+	unsigned long flags;
+	int wakeup = -1;
+
+	spin_lock_irqsave(&device_state_lock, flags);
+	if (udev->state == USB_STATE_NOTATTACHED)
+		;	/* do nothing */
+	else if (new_state != USB_STATE_NOTATTACHED) {
+
+		/* root hub wakeup capabilities are managed out-of-band
+		 * and may involve silicon errata ... ignore them here.
+		 */
+		if (udev->parent) {
+			if (udev->state == USB_STATE_SUSPENDED
+					|| new_state == USB_STATE_SUSPENDED)
+				;	/* No change to wakeup settings */
+			else if (new_state == USB_STATE_CONFIGURED)
+				wakeup = (udev->quirks &
+					USB_QUIRK_IGNORE_REMOTE_WAKEUP) ? 0 :
+					udev->actconfig->desc.bmAttributes &
+					USB_CONFIG_ATT_WAKEUP;
+			else
+				wakeup = 0;
+		}
+		if (udev->state == USB_STATE_SUSPENDED &&
+			new_state != USB_STATE_SUSPENDED)
+			udev->active_duration -= jiffies;
+		else if (new_state == USB_STATE_SUSPENDED &&
+				udev->state != USB_STATE_SUSPENDED)
+			udev->active_duration += jiffies;
+		udev->state = new_state;
+	} else
+		recursively_mark_NOTATTACHED(udev);
+	spin_unlock_irqrestore(&device_state_lock, flags);
+	if (wakeup >= 0)
+		device_set_wakeup_capable(&udev->dev, wakeup);
+}
+EXPORT_SYMBOL_GPL(usb_set_device_state);
+
+/*
+ * Choose a device number.
+ *
+ * Device numbers are used as filenames in usbfs.  On USB-1.1 and
+ * USB-2.0 buses they are also used as device addresses, however on
+ * USB-3.0 buses the address is assigned by the controller hardware
+ * and it usually is not the same as the device number.
+ *
+ * WUSB devices are simple: they have no hubs behind, so the mapping
+ * device <-> virtual port number becomes 1:1. Why? to simplify the
+ * life of the device connection logic in
+ * drivers/usb/wusbcore/devconnect.c. When we do the initial secret
+ * handshake we need to assign a temporary address in the unauthorized
+ * space. For simplicity we use the first virtual port number found to
+ * be free [drivers/usb/wusbcore/devconnect.c:wusbhc_devconnect_ack()]
+ * and that becomes it's address [X < 128] or its unauthorized address
+ * [X | 0x80].
+ *
+ * We add 1 as an offset to the one-based USB-stack port number
+ * (zero-based wusb virtual port index) for two reasons: (a) dev addr
+ * 0 is reserved by USB for default address; (b) Linux's USB stack
+ * uses always #1 for the root hub of the controller. So USB stack's
+ * port #1, which is wusb virtual-port #0 has address #2.
+ *
+ * Devices connected under xHCI are not as simple.  The host controller
+ * supports virtualization, so the hardware assigns device addresses and
+ * the HCD must setup data structures before issuing a set address
+ * command to the hardware.
+ */
+static void choose_devnum(struct usb_device *udev)
+{
+	int		devnum;
+	struct usb_bus	*bus = udev->bus;
+
+	/* be safe when more hub events are proceed in parallel */
+	mutex_lock(&bus->usb_address0_mutex);
+	if (udev->wusb) {
+		devnum = udev->portnum + 1;
+		BUG_ON(test_bit(devnum, bus->devmap.devicemap));
+	} else {
+		/* Try to allocate the next devnum beginning at
+		 * bus->devnum_next. */
+		devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
+					    bus->devnum_next);
+		if (devnum >= 128)
+			devnum = find_next_zero_bit(bus->devmap.devicemap,
+						    128, 1);
+		bus->devnum_next = (devnum >= 127 ? 1 : devnum + 1);
+	}
+	if (devnum < 128) {
+		set_bit(devnum, bus->devmap.devicemap);
+		udev->devnum = devnum;
+	}
+	mutex_unlock(&bus->usb_address0_mutex);
+}
+
+static void release_devnum(struct usb_device *udev)
+{
+	if (udev->devnum > 0) {
+		clear_bit(udev->devnum, udev->bus->devmap.devicemap);
+		udev->devnum = -1;
+	}
+}
+
+static void update_devnum(struct usb_device *udev, int devnum)
+{
+	/* The address for a WUSB device is managed by wusbcore. */
+	if (!udev->wusb)
+		udev->devnum = devnum;
+}
+
+static void hub_free_dev(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	/* Root hubs aren't real devices, so don't free HCD resources */
+	if (hcd->driver->free_dev && udev->parent)
+		hcd->driver->free_dev(hcd, udev);
+}
+
+static void hub_disconnect_children(struct usb_device *udev)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(udev);
+	int i;
+
+	/* Free up all the children before we remove this device */
+	for (i = 0; i < udev->maxchild; i++) {
+		if (hub->ports[i]->child)
+			usb_disconnect(&hub->ports[i]->child);
+	}
+}
+
+/**
+ * usb_disconnect - disconnect a device (usbcore-internal)
+ * @pdev: pointer to device being disconnected
+ * Context: !in_interrupt ()
+ *
+ * Something got disconnected. Get rid of it and all of its children.
+ *
+ * If *pdev is a normal device then the parent hub must already be locked.
+ * If *pdev is a root hub then the caller must hold the usb_bus_list_lock,
+ * which protects the set of root hubs as well as the list of buses.
+ *
+ * Only hub drivers (including virtual root hub drivers for host
+ * controllers) should ever call this.
+ *
+ * This call is synchronous, and may not be used in an interrupt context.
+ */
+void usb_disconnect(struct usb_device **pdev)
+{
+	struct usb_port *port_dev = NULL;
+	struct usb_device *udev = *pdev;
+	struct usb_hub *hub = NULL;
+	int port1 = 1;
+
+	/* mark the device as inactive, so any further urb submissions for
+	 * this device (and any of its children) will fail immediately.
+	 * this quiesces everything except pending urbs.
+	 */
+	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
+	dev_info(&udev->dev, "USB disconnect, device number %d\n",
+			udev->devnum);
+
+	usb_lock_device(udev);
+
+	hub_disconnect_children(udev);
+
+	/* deallocate hcd/hardware state ... nuking all pending urbs and
+	 * cleaning up all state associated with the current configuration
+	 * so that the hardware is now fully quiesced.
+	 */
+	dev_dbg (&udev->dev, "unregistering device\n");
+	usb_disable_device(udev, 0);
+	usb_hcd_synchronize_unlinks(udev);
+
+	if (udev->parent) {
+		port1 = udev->portnum;
+		hub = usb_hub_to_struct_hub(udev->parent);
+		port_dev = hub->ports[port1 - 1];
+
+		sysfs_remove_link(&udev->dev.kobj, "port");
+		sysfs_remove_link(&port_dev->dev.kobj, "device");
+
+		/*
+		 * As usb_port_runtime_resume() de-references udev, make
+		 * sure no resumes occur during removal
+		 */
+		if (!test_and_set_bit(port1, hub->child_usage_bits))
+			pm_runtime_get_sync(&port_dev->dev);
+	}
+
+	usb_remove_ep_devs(&udev->ep0);
+	usb_unlock_device(udev);
+
+	/* Unregister the device.  The device driver is responsible
+	 * for de-configuring the device and invoking the remove-device
+	 * notifier chain (used by usbfs and possibly others).
+	 */
+	device_del(&udev->dev);
+
+	/* Free the device number and delete the parent's children[]
+	 * (or root_hub) pointer.
+	 */
+	release_devnum(udev);
+
+	/* Avoid races with recursively_mark_NOTATTACHED() */
+	spin_lock_irq(&device_state_lock);
+	*pdev = NULL;
+	spin_unlock_irq(&device_state_lock);
+
+	if (port_dev && test_and_clear_bit(port1, hub->child_usage_bits))
+		pm_runtime_put(&port_dev->dev);
+
+	hub_free_dev(udev);
+
+	put_device(&udev->dev);
+}
+
+#ifdef CONFIG_USB_ANNOUNCE_NEW_DEVICES
+static void show_string(struct usb_device *udev, char *id, char *string)
+{
+	if (!string)
+		return;
+	dev_info(&udev->dev, "%s: %s\n", id, string);
+}
+
+static void announce_device(struct usb_device *udev)
+{
+	dev_info(&udev->dev, "New USB device found, idVendor=%04x, idProduct=%04x\n",
+		le16_to_cpu(udev->descriptor.idVendor),
+		le16_to_cpu(udev->descriptor.idProduct));
+	dev_info(&udev->dev,
+		"New USB device strings: Mfr=%d, Product=%d, SerialNumber=%d\n",
+		udev->descriptor.iManufacturer,
+		udev->descriptor.iProduct,
+		udev->descriptor.iSerialNumber);
+	show_string(udev, "Product", udev->product);
+	show_string(udev, "Manufacturer", udev->manufacturer);
+	show_string(udev, "SerialNumber", udev->serial);
+}
+#else
+static inline void announce_device(struct usb_device *udev) { }
+#endif
+
+
+/**
+ * usb_enumerate_device_otg - FIXME (usbcore-internal)
+ * @udev: newly addressed device (in ADDRESS state)
+ *
+ * Finish enumeration for On-The-Go devices
+ *
+ * Return: 0 if successful. A negative error code otherwise.
+ */
+static int usb_enumerate_device_otg(struct usb_device *udev)
+{
+	int err = 0;
+
+#ifdef	CONFIG_USB_OTG
+	/*
+	 * OTG-aware devices on OTG-capable root hubs may be able to use SRP,
+	 * to wake us after we've powered off VBUS; and HNP, switching roles
+	 * "host" to "peripheral".  The OTG descriptor helps figure this out.
+	 */
+	if (!udev->bus->is_b_host
+			&& udev->config
+			&& udev->parent == udev->bus->root_hub) {
+		struct usb_otg_descriptor	*desc = NULL;
+		struct usb_bus			*bus = udev->bus;
+
+		/* descriptor may appear anywhere in config */
+		if (__usb_get_extra_descriptor (udev->rawdescriptors[0],
+					le16_to_cpu(udev->config[0].desc.wTotalLength),
+					USB_DT_OTG, (void **) &desc) == 0) {
+			if (desc->bmAttributes & USB_OTG_HNP) {
+				unsigned		port1 = udev->portnum;
+
+				dev_info(&udev->dev,
+					"Dual-Role OTG device on %sHNP port\n",
+					(port1 == bus->otg_port)
+						? "" : "non-");
+
+				/* enable HNP before suspend, it's simpler */
+				if (port1 == bus->otg_port)
+					bus->b_hnp_enable = 1;
+				err = usb_control_msg(udev,
+					usb_sndctrlpipe(udev, 0),
+					USB_REQ_SET_FEATURE, 0,
+					bus->b_hnp_enable
+						? USB_DEVICE_B_HNP_ENABLE
+						: USB_DEVICE_A_ALT_HNP_SUPPORT,
+					0, NULL, 0, USB_CTRL_SET_TIMEOUT);
+				if (err < 0) {
+					/* OTG MESSAGE: report errors here,
+					 * customize to match your product.
+					 */
+					dev_info(&udev->dev,
+						"can't set HNP mode: %d\n",
+						err);
+					bus->b_hnp_enable = 0;
+				}
+			}
+		}
+	}
+#endif
+	return err;
+}
+
+
+/**
+ * usb_enumerate_device - Read device configs/intfs/otg (usbcore-internal)
+ * @udev: newly addressed device (in ADDRESS state)
+ *
+ * This is only called by usb_new_device() and usb_authorize_device()
+ * and FIXME -- all comments that apply to them apply here wrt to
+ * environment.
+ *
+ * If the device is WUSB and not authorized, we don't attempt to read
+ * the string descriptors, as they will be errored out by the device
+ * until it has been authorized.
+ *
+ * Return: 0 if successful. A negative error code otherwise.
+ */
+static int usb_enumerate_device(struct usb_device *udev)
+{
+	int err;
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	if (udev->config == NULL) {
+		err = usb_get_configuration(udev);
+		if (err < 0) {
+			if (err != -ENODEV)
+				dev_err(&udev->dev, "can't read configurations, error %d\n",
+						err);
+			return err;
+		}
+	}
+
+	/* read the standard strings and cache them if present */
+	udev->product = usb_cache_string(udev, udev->descriptor.iProduct);
+	udev->manufacturer = usb_cache_string(udev,
+					      udev->descriptor.iManufacturer);
+	udev->serial = usb_cache_string(udev, udev->descriptor.iSerialNumber);
+
+	err = usb_enumerate_device_otg(udev);
+	if (err < 0)
+		return err;
+
+	if (IS_ENABLED(CONFIG_USB_OTG_WHITELIST) && hcd->tpl_support &&
+		!is_targeted(udev)) {
+		/* Maybe it can talk to us, though we can't talk to it.
+		 * (Includes HNP test device.)
+		 */
+		if (IS_ENABLED(CONFIG_USB_OTG) && (udev->bus->b_hnp_enable
+			|| udev->bus->is_b_host)) {
+			err = usb_port_suspend(udev, PMSG_AUTO_SUSPEND);
+			if (err < 0)
+				dev_dbg(&udev->dev, "HNP fail, %d\n", err);
+		}
+		return -ENOTSUPP;
+	}
+
+	usb_detect_interface_quirks(udev);
+
+	return 0;
+}
+
+static void set_usb_port_removable(struct usb_device *udev)
+{
+	struct usb_device *hdev = udev->parent;
+	struct usb_hub *hub;
+	u8 port = udev->portnum;
+	u16 wHubCharacteristics;
+	bool removable = true;
+
+	if (!hdev)
+		return;
+
+	hub = usb_hub_to_struct_hub(udev->parent);
+
+	/*
+	 * If the platform firmware has provided information about a port,
+	 * use that to determine whether it's removable.
+	 */
+	switch (hub->ports[udev->portnum - 1]->connect_type) {
+	case USB_PORT_CONNECT_TYPE_HOT_PLUG:
+		udev->removable = USB_DEVICE_REMOVABLE;
+		return;
+	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
+	case USB_PORT_NOT_USED:
+		udev->removable = USB_DEVICE_FIXED;
+		return;
+	default:
+		break;
+	}
+
+	/*
+	 * Otherwise, check whether the hub knows whether a port is removable
+	 * or not
+	 */
+	wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
+
+	if (!(wHubCharacteristics & HUB_CHAR_COMPOUND))
+		return;
+
+	if (hub_is_superspeed(hdev)) {
+		if (le16_to_cpu(hub->descriptor->u.ss.DeviceRemovable)
+				& (1 << port))
+			removable = false;
+	} else {
+		if (hub->descriptor->u.hs.DeviceRemovable[port / 8] & (1 << (port % 8)))
+			removable = false;
+	}
+
+	if (removable)
+		udev->removable = USB_DEVICE_REMOVABLE;
+	else
+		udev->removable = USB_DEVICE_FIXED;
+
+}
+
+/**
+ * usb_new_device - perform initial device setup (usbcore-internal)
+ * @udev: newly addressed device (in ADDRESS state)
+ *
+ * This is called with devices which have been detected but not fully
+ * enumerated.  The device descriptor is available, but not descriptors
+ * for any device configuration.  The caller must have locked either
+ * the parent hub (if udev is a normal device) or else the
+ * usb_bus_list_lock (if udev is a root hub).  The parent's pointer to
+ * udev has already been installed, but udev is not yet visible through
+ * sysfs or other filesystem code.
+ *
+ * This call is synchronous, and may not be used in an interrupt context.
+ *
+ * Only the hub driver or root-hub registrar should ever call this.
+ *
+ * Return: Whether the device is configured properly or not. Zero if the
+ * interface was registered with the driver core; else a negative errno
+ * value.
+ *
+ */
+int usb_new_device(struct usb_device *udev)
+{
+	int err;
+
+	if (udev->parent) {
+		/* Initialize non-root-hub device wakeup to disabled;
+		 * device (un)configuration controls wakeup capable
+		 * sysfs power/wakeup controls wakeup enabled/disabled
+		 */
+		device_init_wakeup(&udev->dev, 0);
+	}
+
+	/* Tell the runtime-PM framework the device is active */
+	pm_runtime_set_active(&udev->dev);
+	pm_runtime_get_noresume(&udev->dev);
+	pm_runtime_use_autosuspend(&udev->dev);
+	pm_runtime_enable(&udev->dev);
+
+	/* By default, forbid autosuspend for all devices.  It will be
+	 * allowed for hubs during binding.
+	 */
+	usb_disable_autosuspend(udev);
+
+	err = usb_enumerate_device(udev);	/* Read descriptors */
+	if (err < 0)
+		goto fail;
+	dev_dbg(&udev->dev, "udev %d, busnum %d, minor = %d\n",
+			udev->devnum, udev->bus->busnum,
+			(((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
+	/* export the usbdev device-node for libusb */
+	udev->dev.devt = MKDEV(USB_DEVICE_MAJOR,
+			(((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
+
+	/* Tell the world! */
+	announce_device(udev);
+
+	if (udev->serial)
+		add_device_randomness(udev->serial, strlen(udev->serial));
+	if (udev->product)
+		add_device_randomness(udev->product, strlen(udev->product));
+	if (udev->manufacturer)
+		add_device_randomness(udev->manufacturer,
+				      strlen(udev->manufacturer));
+
+	device_enable_async_suspend(&udev->dev);
+
+	/* check whether the hub or firmware marks this port as non-removable */
+	if (udev->parent)
+		set_usb_port_removable(udev);
+
+	/* Register the device.  The device driver is responsible
+	 * for configuring the device and invoking the add-device
+	 * notifier chain (used by usbfs and possibly others).
+	 */
+	err = device_add(&udev->dev);
+	if (err) {
+		dev_err(&udev->dev, "can't device_add, error %d\n", err);
+		goto fail;
+	}
+
+	/* Create link files between child device and usb port device. */
+	if (udev->parent) {
+		struct usb_hub *hub = usb_hub_to_struct_hub(udev->parent);
+		int port1 = udev->portnum;
+		struct usb_port	*port_dev = hub->ports[port1 - 1];
+
+		err = sysfs_create_link(&udev->dev.kobj,
+				&port_dev->dev.kobj, "port");
+		if (err)
+			goto fail;
+
+		err = sysfs_create_link(&port_dev->dev.kobj,
+				&udev->dev.kobj, "device");
+		if (err) {
+			sysfs_remove_link(&udev->dev.kobj, "port");
+			goto fail;
+		}
+
+		if (!test_and_set_bit(port1, hub->child_usage_bits))
+			pm_runtime_get_sync(&port_dev->dev);
+	}
+
+	(void) usb_create_ep_devs(&udev->dev, &udev->ep0, udev);
+	usb_mark_last_busy(udev);
+	pm_runtime_put_sync_autosuspend(&udev->dev);
+	return err;
+
+fail:
+	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
+	pm_runtime_disable(&udev->dev);
+	pm_runtime_set_suspended(&udev->dev);
+	return err;
+}
+
+
+/**
+ * usb_deauthorize_device - deauthorize a device (usbcore-internal)
+ * @usb_dev: USB device
+ *
+ * Move the USB device to a very basic state where interfaces are disabled
+ * and the device is in fact unconfigured and unusable.
+ *
+ * We share a lock (that we have) with device_del(), so we need to
+ * defer its call.
+ *
+ * Return: 0.
+ */
+int usb_deauthorize_device(struct usb_device *usb_dev)
+{
+	usb_lock_device(usb_dev);
+	if (usb_dev->authorized == 0)
+		goto out_unauthorized;
+
+	usb_dev->authorized = 0;
+	usb_set_configuration(usb_dev, -1);
+
+out_unauthorized:
+	usb_unlock_device(usb_dev);
+	return 0;
+}
+
+
+int usb_authorize_device(struct usb_device *usb_dev)
+{
+	int result = 0, c;
+
+	usb_lock_device(usb_dev);
+	if (usb_dev->authorized == 1)
+		goto out_authorized;
+
+	result = usb_autoresume_device(usb_dev);
+	if (result < 0) {
+		dev_err(&usb_dev->dev,
+			"can't autoresume for authorization: %d\n", result);
+		goto error_autoresume;
+	}
+
+	if (usb_dev->wusb) {
+		result = usb_get_device_descriptor(usb_dev, sizeof(usb_dev->descriptor));
+		if (result < 0) {
+			dev_err(&usb_dev->dev, "can't re-read device descriptor for "
+				"authorization: %d\n", result);
+			goto error_device_descriptor;
+		}
+	}
+
+	usb_dev->authorized = 1;
+	/* Choose and set the configuration.  This registers the interfaces
+	 * with the driver core and lets interface drivers bind to them.
+	 */
+	c = usb_choose_configuration(usb_dev);
+	if (c >= 0) {
+		result = usb_set_configuration(usb_dev, c);
+		if (result) {
+			dev_err(&usb_dev->dev,
+				"can't set config #%d, error %d\n", c, result);
+			/* This need not be fatal.  The user can try to
+			 * set other configurations. */
+		}
+	}
+	dev_info(&usb_dev->dev, "authorized to connect\n");
+
+error_device_descriptor:
+	usb_autosuspend_device(usb_dev);
+error_autoresume:
+out_authorized:
+	usb_unlock_device(usb_dev);	/* complements locktree */
+	return result;
+}
+
+
+/* Returns 1 if @hub is a WUSB root hub, 0 otherwise */
+static unsigned hub_is_wusb(struct usb_hub *hub)
+{
+	struct usb_hcd *hcd;
+	if (hub->hdev->parent != NULL)  /* not a root hub? */
+		return 0;
+	hcd = container_of(hub->hdev->bus, struct usb_hcd, self);
+	return hcd->wireless;
+}
+
+
+#define PORT_RESET_TRIES	5
+#define SET_ADDRESS_TRIES	2
+#define GET_DESCRIPTOR_TRIES	2
+#define SET_CONFIG_TRIES	(2 * (use_both_schemes + 1))
+#define USE_NEW_SCHEME(i)	((i) / 2 == (int)old_scheme_first)
+
+#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	800
+
+/*
+ * "New scheme" enumeration causes an extra state transition to be
+ * exposed to an xhci host and causes USB3 devices to receive control
+ * commands in the default state.  This has been seen to cause
+ * enumeration failures, so disable this enumeration scheme for USB3
+ * devices.
+ */
+static bool use_new_scheme(struct usb_device *udev, int retry)
+{
+	if (udev->speed == USB_SPEED_SUPER)
+		return false;
+
+	return USE_NEW_SCHEME(retry);
+}
+
+/* Is a USB 3.0 port in the Inactive or Compliance Mode state?
+ * Port worm reset is required to recover
+ */
+static bool hub_port_warm_reset_required(struct usb_hub *hub, int port1,
+		u16 portstatus)
+{
+	u16 link_state;
+
+	if (!hub_is_superspeed(hub->hdev))
+		return false;
+
+	if (test_bit(port1, hub->warm_reset_bits))
+		return true;
+
+	link_state = portstatus & USB_PORT_STAT_LINK_STATE;
+	return link_state == USB_SS_PORT_LS_SS_INACTIVE
+		|| link_state == USB_SS_PORT_LS_COMP_MOD;
+}
+
+static int hub_port_wait_reset(struct usb_hub *hub, int port1,
+			struct usb_device *udev, unsigned int delay, bool warm)
+{
+	int delay_time, ret;
+	u16 portstatus;
+	u16 portchange;
+
+	for (delay_time = 0;
+			delay_time < HUB_RESET_TIMEOUT;
+			delay_time += delay) {
+		/* wait to give the device a chance to reset */
+		msleep(delay);
+
+		/* read and decode port status */
+		ret = hub_port_status(hub, port1, &portstatus, &portchange);
+		if (ret < 0)
+			return ret;
+
+		/* The port state is unknown until the reset completes. */
+		if (!(portstatus & USB_PORT_STAT_RESET))
+			break;
+
+		/* 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->ports[port1 - 1]->dev,
+				"not %sreset yet, waiting %dms\n",
+				warm ? "warm " : "", delay);
+	}
+
+	if ((portstatus & USB_PORT_STAT_RESET))
+		return -EBUSY;
+
+	if (hub_port_warm_reset_required(hub, port1, portstatus))
+		return -ENOTCONN;
+
+	/* Device went away? */
+	if (!(portstatus & USB_PORT_STAT_CONNECTION))
+		return -ENOTCONN;
+
+	/* bomb out completely if the connection bounced.  A USB 3.0
+	 * connection may bounce if multiple warm resets were issued,
+	 * but the device may have successfully re-connected. Ignore it.
+	 */
+	if (!hub_is_superspeed(hub->hdev) &&
+			(portchange & USB_PORT_STAT_C_CONNECTION))
+		return -ENOTCONN;
+
+	if (!(portstatus & USB_PORT_STAT_ENABLE))
+		return -EBUSY;
+
+	if (!udev)
+		return 0;
+
+	if (hub_is_wusb(hub))
+		udev->speed = USB_SPEED_WIRELESS;
+	else if (hub_is_superspeed(hub->hdev))
+		udev->speed = USB_SPEED_SUPER;
+	else if (portstatus & USB_PORT_STAT_HIGH_SPEED)
+		udev->speed = USB_SPEED_HIGH;
+	else if (portstatus & USB_PORT_STAT_LOW_SPEED)
+		udev->speed = USB_SPEED_LOW;
+	else
+		udev->speed = USB_SPEED_FULL;
+	return 0;
+}
+
+/* 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 i, status;
+	u16 portchange, portstatus;
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+
+	if (!hub_is_superspeed(hub->hdev)) {
+		if (warm) {
+			dev_err(hub->intfdev, "only USB3 hub support "
+						"warm reset\n");
+			return -EINVAL;
+		}
+		/* 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 (!warm) {
+		/*
+		 * If the caller hasn't explicitly requested a warm reset,
+		 * double check and see if one is needed.
+		 */
+		if (hub_port_status(hub, port1, &portstatus, &portchange) == 0)
+			if (hub_port_warm_reset_required(hub, port1,
+							portstatus))
+				warm = true;
+	}
+	clear_bit(port1, hub->warm_reset_bits);
+
+	/* 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 == -ENODEV) {
+			;	/* The hub is gone */
+		} else if (status) {
+			dev_err(&port_dev->dev,
+					"cannot %sreset (err = %d)\n",
+					warm ? "warm " : "", status);
+		} else {
+			status = hub_port_wait_reset(hub, port1, udev, delay,
+								warm);
+			if (status && status != -ENOTCONN && status != -ENODEV)
+				dev_dbg(hub->intfdev,
+						"port_wait_reset: err = %d\n",
+						status);
+		}
+
+		/* Check for disconnect or reset */
+		if (status == 0 || status == -ENOTCONN || status == -ENODEV) {
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_RESET);
+
+			if (!hub_is_superspeed(hub->hdev))
+				goto done;
+
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_BH_PORT_RESET);
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_PORT_LINK_STATE);
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_CONNECTION);
+
+			/*
+			 * If a USB 3.0 device migrates from reset to an error
+			 * state, re-issue the warm reset.
+			 */
+			if (hub_port_status(hub, port1,
+					&portstatus, &portchange) < 0)
+				goto done;
+
+			if (!hub_port_warm_reset_required(hub, port1,
+					portstatus))
+				goto done;
+
+			/*
+			 * If the port is in SS.Inactive or Compliance Mode, the
+			 * hot or warm reset failed.  Try another warm reset.
+			 */
+			if (!warm) {
+				dev_dbg(&port_dev->dev,
+						"hot reset failed, warm reset\n");
+				warm = true;
+			}
+		}
+
+		dev_dbg(&port_dev->dev,
+				"not enabled, trying %sreset again...\n",
+				warm ? "warm " : "");
+		delay = HUB_LONG_RESET_TIME;
+	}
+
+	dev_err(&port_dev->dev, "Cannot enable. Maybe the USB cable is bad?\n");
+
+done:
+	if (status == 0) {
+		/* TRSTRCY = 10 ms; plus some extra */
+		msleep(10 + 40);
+		if (udev) {
+			struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+			update_devnum(udev, 0);
+			/* The xHC may think the device is already reset,
+			 * so ignore the status.
+			 */
+			if (hcd->driver->reset_device)
+				hcd->driver->reset_device(hcd, udev);
+
+			usb_set_device_state(udev, USB_STATE_DEFAULT);
+		}
+	} else {
+		if (udev)
+			usb_set_device_state(udev, USB_STATE_NOTATTACHED);
+	}
+
+	if (!hub_is_superspeed(hub->hdev))
+		up_read(&ehci_cf_port_reset_rwsem);
+
+	return status;
+}
+
+/* Check if a port is power on */
+static int port_is_power_on(struct usb_hub *hub, unsigned portstatus)
+{
+	int ret = 0;
+
+	if (hub_is_superspeed(hub->hdev)) {
+		if (portstatus & USB_SS_PORT_STAT_POWER)
+			ret = 1;
+	} else {
+		if (portstatus & USB_PORT_STAT_POWER)
+			ret = 1;
+	}
+
+	return ret;
+}
+
+static void usb_lock_port(struct usb_port *port_dev)
+		__acquires(&port_dev->status_lock)
+{
+	mutex_lock(&port_dev->status_lock);
+	__acquire(&port_dev->status_lock);
+}
+
+static void usb_unlock_port(struct usb_port *port_dev)
+		__releases(&port_dev->status_lock)
+{
+	mutex_unlock(&port_dev->status_lock);
+	__release(&port_dev->status_lock);
+}
+
+#ifdef	CONFIG_PM
+
+/* Check if a port is suspended(USB2.0 port) or in U3 state(USB3.0 port) */
+static int port_is_suspended(struct usb_hub *hub, unsigned portstatus)
+{
+	int ret = 0;
+
+	if (hub_is_superspeed(hub->hdev)) {
+		if ((portstatus & USB_PORT_STAT_LINK_STATE)
+				== USB_SS_PORT_LS_U3)
+			ret = 1;
+	} else {
+		if (portstatus & USB_PORT_STAT_SUSPEND)
+			ret = 1;
+	}
+
+	return ret;
+}
+
+/* Determine whether the device on a port is ready for a normal resume,
+ * is ready for a reset-resume, or should be disconnected.
+ */
+static int check_port_resume_type(struct usb_device *udev,
+		struct usb_hub *hub, int port1,
+		int status, u16 portchange, u16 portstatus)
+{
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	int retries = 3;
+
+ retry:
+	/* Is a warm reset needed to recover the connection? */
+	if (status == 0 && udev->reset_resume
+		&& hub_port_warm_reset_required(hub, port1, portstatus)) {
+		/* pass */;
+	}
+	/* Is the device still present? */
+	else if (status || port_is_suspended(hub, portstatus) ||
+			!port_is_power_on(hub, portstatus)) {
+		if (status >= 0)
+			status = -ENODEV;
+	} else if (!(portstatus & USB_PORT_STAT_CONNECTION)) {
+		if (retries--) {
+			usleep_range(200, 300);
+			status = hub_port_status(hub, port1, &portstatus,
+							     &portchange);
+			goto retry;
+		}
+		status = -ENODEV;
+	}
+
+	/* Can't do a normal resume if the port isn't enabled,
+	 * so try a reset-resume instead.
+	 */
+	else if (!(portstatus & USB_PORT_STAT_ENABLE) && !udev->reset_resume) {
+		if (udev->persist_enabled)
+			udev->reset_resume = 1;
+		else
+			status = -ENODEV;
+	}
+
+	if (status) {
+		dev_dbg(&port_dev->dev, "status %04x.%04x after resume, %d\n",
+				portchange, portstatus, status);
+	} else if (udev->reset_resume) {
+
+		/* Late port handoff can set status-change bits */
+		if (portchange & USB_PORT_STAT_C_CONNECTION)
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_CONNECTION);
+		if (portchange & USB_PORT_STAT_C_ENABLE)
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_ENABLE);
+	}
+
+	return status;
+}
+
+int usb_disable_ltm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	/* Check if the roothub and device supports LTM. */
+	if (!usb_device_supports_ltm(hcd->self.root_hub) ||
+			!usb_device_supports_ltm(udev))
+		return 0;
+
+	/* Clear Feature LTM Enable can only be sent if the device is
+	 * configured.
+	 */
+	if (!udev->actconfig)
+		return 0;
+
+	return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+			USB_REQ_CLEAR_FEATURE, USB_RECIP_DEVICE,
+			USB_DEVICE_LTM_ENABLE, 0, NULL, 0,
+			USB_CTRL_SET_TIMEOUT);
+}
+EXPORT_SYMBOL_GPL(usb_disable_ltm);
+
+void usb_enable_ltm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	/* Check if the roothub and device supports LTM. */
+	if (!usb_device_supports_ltm(hcd->self.root_hub) ||
+			!usb_device_supports_ltm(udev))
+		return;
+
+	/* Set Feature LTM Enable can only be sent if the device is
+	 * configured.
+	 */
+	if (!udev->actconfig)
+		return;
+
+	usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+			USB_REQ_SET_FEATURE, USB_RECIP_DEVICE,
+			USB_DEVICE_LTM_ENABLE, 0, NULL, 0,
+			USB_CTRL_SET_TIMEOUT);
+}
+EXPORT_SYMBOL_GPL(usb_enable_ltm);
+
+/*
+ * usb_enable_remote_wakeup - enable remote wakeup for a device
+ * @udev: target device
+ *
+ * For USB-2 devices: Set the device's remote wakeup feature.
+ *
+ * For USB-3 devices: Assume there's only one function on the device and
+ * enable remote wake for the first interface.  FIXME if the interface
+ * association descriptor shows there's more than one function.
+ */
+static int usb_enable_remote_wakeup(struct usb_device *udev)
+{
+	if (udev->speed < USB_SPEED_SUPER)
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE, USB_RECIP_DEVICE,
+				USB_DEVICE_REMOTE_WAKEUP, 0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	else
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE, USB_RECIP_INTERFACE,
+				USB_INTRF_FUNC_SUSPEND,
+				USB_INTRF_FUNC_SUSPEND_RW |
+					USB_INTRF_FUNC_SUSPEND_LP,
+				NULL, 0, USB_CTRL_SET_TIMEOUT);
+}
+
+/*
+ * usb_disable_remote_wakeup - disable remote wakeup for a device
+ * @udev: target device
+ *
+ * For USB-2 devices: Clear the device's remote wakeup feature.
+ *
+ * For USB-3 devices: Assume there's only one function on the device and
+ * disable remote wake for the first interface.  FIXME if the interface
+ * association descriptor shows there's more than one function.
+ */
+static int usb_disable_remote_wakeup(struct usb_device *udev)
+{
+	if (udev->speed < USB_SPEED_SUPER)
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_CLEAR_FEATURE, USB_RECIP_DEVICE,
+				USB_DEVICE_REMOTE_WAKEUP, 0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	else
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_CLEAR_FEATURE, USB_RECIP_INTERFACE,
+				USB_INTRF_FUNC_SUSPEND,	0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+}
+
+/* Count of wakeup-enabled devices at or below udev */
+static unsigned wakeup_enabled_descendants(struct usb_device *udev)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(udev);
+
+	return udev->do_remote_wakeup +
+			(hub ? hub->wakeup_enabled_descendants : 0);
+}
+
+/*
+ * usb_port_suspend - suspend a usb device's upstream port
+ * @udev: device that's no longer in active use, not a root hub
+ * Context: must be able to sleep; device not locked; pm locks held
+ *
+ * Suspends a USB device that isn't in active use, conserving power.
+ * Devices may wake out of a suspend, if anything important happens,
+ * using the remote wakeup mechanism.  They may also be taken out of
+ * suspend by the host, using usb_port_resume().  It's also routine
+ * to disconnect devices while they are suspended.
+ *
+ * This only affects the USB hardware for a device; its interfaces
+ * (and, for hubs, child devices) must already have been suspended.
+ *
+ * Selective port suspend reduces power; most suspended devices draw
+ * less than 500 uA.  It's also used in OTG, along with remote wakeup.
+ * All devices below the suspended port are also suspended.
+ *
+ * Devices leave suspend state when the host wakes them up.  Some devices
+ * also support "remote wakeup", where the device can activate the USB
+ * tree above them to deliver data, such as a keypress or packet.  In
+ * some cases, this wakes the USB host.
+ *
+ * Suspending OTG devices may trigger HNP, if that's been enabled
+ * between a pair of dual-role devices.  That will change roles, such
+ * as from A-Host to A-Peripheral or from B-Host back to B-Peripheral.
+ *
+ * Devices on USB hub ports have only one "suspend" state, corresponding
+ * to ACPI D2, "may cause the device to lose some context".
+ * State transitions include:
+ *
+ *   - suspend, resume ... when the VBUS power link stays live
+ *   - suspend, disconnect ... VBUS lost
+ *
+ * Once VBUS drop breaks the circuit, the port it's using has to go through
+ * normal re-enumeration procedures, starting with enabling VBUS power.
+ * Other than re-initializing the hub (plug/unplug, except for root hubs),
+ * Linux (2.6) currently has NO mechanisms to initiate that:  no hub_wq
+ * timer, no SRP, no requests through sysfs.
+ *
+ * If Runtime PM isn't enabled or used, non-SuperSpeed devices may not get
+ * suspended until their bus goes into global suspend (i.e., the root
+ * hub is suspended).  Nevertheless, we change @udev->state to
+ * USB_STATE_SUSPENDED as this is the device's "logical" state.  The actual
+ * upstream port setting is stored in @udev->port_is_suspended.
+ *
+ * Returns 0 on success, else negative errno.
+ */
+int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
+{
+	struct usb_hub	*hub = usb_hub_to_struct_hub(udev->parent);
+	struct usb_port *port_dev = hub->ports[udev->portnum - 1];
+	int		port1 = udev->portnum;
+	int		status;
+	bool		really_suspend = true;
+
+	usb_lock_port(port_dev);
+
+	/* enable remote wakeup when appropriate; this lets the device
+	 * wake up the upstream hub (including maybe the root hub).
+	 *
+	 * NOTE:  OTG devices may issue remote wakeup (or SRP) even when
+	 * we don't explicitly enable it here.
+	 */
+	if (udev->do_remote_wakeup) {
+		status = usb_enable_remote_wakeup(udev);
+		if (status) {
+			dev_dbg(&udev->dev, "won't remote wakeup, status %d\n",
+					status);
+			/* bail if autosuspend is requested */
+			if (PMSG_IS_AUTO(msg))
+				goto err_wakeup;
+		}
+	}
+
+	/* disable USB2 hardware LPM */
+	if (udev->usb2_hw_lpm_enabled == 1)
+		usb_set_usb2_hardware_lpm(udev, 0);
+
+	if (usb_disable_ltm(udev)) {
+		dev_err(&udev->dev, "Failed to disable LTM before suspend\n.");
+		status = -ENOMEM;
+		if (PMSG_IS_AUTO(msg))
+			goto err_ltm;
+	}
+	if (usb_unlocked_disable_lpm(udev)) {
+		dev_err(&udev->dev, "Failed to disable LPM before suspend\n.");
+		status = -ENOMEM;
+		if (PMSG_IS_AUTO(msg))
+			goto err_lpm3;
+	}
+
+	/* see 7.1.7.6 */
+	if (hub_is_superspeed(hub->hdev))
+		status = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_U3);
+
+	/*
+	 * For system suspend, we do not need to enable the suspend feature
+	 * on individual USB-2 ports.  The devices will automatically go
+	 * into suspend a few ms after the root hub stops sending packets.
+	 * The USB 2.0 spec calls this "global suspend".
+	 *
+	 * However, many USB hubs have a bug: They don't relay wakeup requests
+	 * from a downstream port if the port's suspend feature isn't on.
+	 * Therefore we will turn on the suspend feature if udev or any of its
+	 * descendants is enabled for remote wakeup.
+	 */
+	else if (PMSG_IS_AUTO(msg) || wakeup_enabled_descendants(udev) > 0)
+		status = set_port_feature(hub->hdev, port1,
+				USB_PORT_FEAT_SUSPEND);
+	else {
+		really_suspend = false;
+		status = 0;
+	}
+	if (status) {
+		dev_dbg(&port_dev->dev, "can't suspend, status %d\n", status);
+
+		/* Try to enable USB3 LPM and LTM again */
+		usb_unlocked_enable_lpm(udev);
+ err_lpm3:
+		usb_enable_ltm(udev);
+ err_ltm:
+		/* Try to enable USB2 hardware LPM again */
+		if (udev->usb2_hw_lpm_capable == 1)
+			usb_set_usb2_hardware_lpm(udev, 1);
+
+		if (udev->do_remote_wakeup)
+			(void) usb_disable_remote_wakeup(udev);
+ err_wakeup:
+
+		/* System sleep transitions should never fail */
+		if (!PMSG_IS_AUTO(msg))
+			status = 0;
+	} else {
+		dev_dbg(&udev->dev, "usb %ssuspend, wakeup %d\n",
+				(PMSG_IS_AUTO(msg) ? "auto-" : ""),
+				udev->do_remote_wakeup);
+		if (really_suspend) {
+			udev->port_is_suspended = 1;
+
+			/* device has up to 10 msec to fully suspend */
+			msleep(10);
+		}
+		usb_set_device_state(udev, USB_STATE_SUSPENDED);
+	}
+
+	if (status == 0 && !udev->do_remote_wakeup && udev->persist_enabled
+			&& test_and_clear_bit(port1, hub->child_usage_bits))
+		pm_runtime_put_sync(&port_dev->dev);
+
+	usb_mark_last_busy(hub->hdev);
+
+	usb_unlock_port(port_dev);
+	return status;
+}
+
+/*
+ * If the USB "suspend" state is in use (rather than "global suspend"),
+ * many devices will be individually taken out of suspend state using
+ * special "resume" signaling.  This routine kicks in shortly after
+ * hardware resume signaling is finished, either because of selective
+ * resume (by host) or remote wakeup (by device) ... now see what changed
+ * in the tree that's rooted at this device.
+ *
+ * If @udev->reset_resume is set then the device is reset before the
+ * status check is done.
+ */
+static int finish_port_resume(struct usb_device *udev)
+{
+	int	status = 0;
+	u16	devstatus = 0;
+
+	/* caller owns the udev device lock */
+	dev_dbg(&udev->dev, "%s\n",
+		udev->reset_resume ? "finish reset-resume" : "finish resume");
+
+	/* usb ch9 identifies four variants of SUSPENDED, based on what
+	 * state the device resumes to.  Linux currently won't see the
+	 * first two on the host side; they'd be inside hub_port_init()
+	 * during many timeouts, but hub_wq can't suspend until later.
+	 */
+	usb_set_device_state(udev, udev->actconfig
+			? USB_STATE_CONFIGURED
+			: USB_STATE_ADDRESS);
+
+	/* 10.5.4.5 says not to reset a suspended port if the attached
+	 * device is enabled for remote wakeup.  Hence the reset
+	 * operation is carried out here, after the port has been
+	 * resumed.
+	 */
+	if (udev->reset_resume) {
+		/*
+		 * If the device morphs or switches modes when it is reset,
+		 * we don't want to perform a reset-resume.  We'll fail the
+		 * resume, which will cause a logical disconnect, and then
+		 * the device will be rediscovered.
+		 */
+ retry_reset_resume:
+		if (udev->quirks & USB_QUIRK_RESET)
+			status = -ENODEV;
+		else
+			status = usb_reset_and_verify_device(udev);
+	}
+
+	/* 10.5.4.5 says be sure devices in the tree are still there.
+	 * For now let's assume the device didn't go crazy on resume,
+	 * and device drivers will know about any resume quirks.
+	 */
+	if (status == 0) {
+		devstatus = 0;
+		status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
+
+		/* If a normal resume failed, try doing a reset-resume */
+		if (status && !udev->reset_resume && udev->persist_enabled) {
+			dev_dbg(&udev->dev, "retry with reset-resume\n");
+			udev->reset_resume = 1;
+			goto retry_reset_resume;
+		}
+	}
+
+	if (status) {
+		dev_dbg(&udev->dev, "gone after usb resume? status %d\n",
+				status);
+	/*
+	 * There are a few quirky devices which violate the standard
+	 * by claiming to have remote wakeup enabled after a reset,
+	 * which crash if the feature is cleared, hence check for
+	 * udev->reset_resume
+	 */
+	} else if (udev->actconfig && !udev->reset_resume) {
+		if (udev->speed < USB_SPEED_SUPER) {
+			if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
+				status = usb_disable_remote_wakeup(udev);
+		} else {
+			status = usb_get_status(udev, USB_RECIP_INTERFACE, 0,
+					&devstatus);
+			if (!status && devstatus & (USB_INTRF_STAT_FUNC_RW_CAP
+					| USB_INTRF_STAT_FUNC_RW))
+				status = usb_disable_remote_wakeup(udev);
+		}
+
+		if (status)
+			dev_dbg(&udev->dev,
+				"disable remote wakeup, status %d\n",
+				status);
+		status = 0;
+	}
+	return status;
+}
+
+/*
+ * There are some SS USB devices which take longer time for link training.
+ * XHCI specs 4.19.4 says that when Link training is successful, port
+ * sets CSC bit to 1. So if SW reads port status before successful link
+ * training, then it will not find device to be present.
+ * USB Analyzer log with such buggy devices show that in some cases
+ * device switch on the RX termination after long delay of host enabling
+ * the VBUS. In few other cases it has been seen that device fails to
+ * negotiate link training in first attempt. It has been
+ * reported till now that few devices take as long as 2000 ms to train
+ * the link after host enabling its VBUS and termination. Following
+ * routine implements a 2000 ms timeout for link training. If in a case
+ * link trains before timeout, loop will exit earlier.
+ *
+ * FIXME: If a device was connected before suspend, but was removed
+ * while system was asleep, then the loop in the following routine will
+ * only exit at timeout.
+ *
+ * This routine should only be called when persist is enabled for a SS
+ * device.
+ */
+static int wait_for_ss_port_enable(struct usb_device *udev,
+		struct usb_hub *hub, int *port1,
+		u16 *portchange, u16 *portstatus)
+{
+	int status = 0, delay_ms = 0;
+
+	while (delay_ms < 2000) {
+		if (status || *portstatus & USB_PORT_STAT_CONNECTION)
+			break;
+		msleep(20);
+		delay_ms += 20;
+		status = hub_port_status(hub, *port1, portstatus, portchange);
+	}
+	return status;
+}
+
+/*
+ * usb_port_resume - re-activate a suspended usb device's upstream port
+ * @udev: device to re-activate, not a root hub
+ * Context: must be able to sleep; device not locked; pm locks held
+ *
+ * This will re-activate the suspended device, increasing power usage
+ * while letting drivers communicate again with its endpoints.
+ * USB resume explicitly guarantees that the power session between
+ * the host and the device is the same as it was when the device
+ * suspended.
+ *
+ * If @udev->reset_resume is set then this routine won't check that the
+ * port is still enabled.  Furthermore, finish_port_resume() above will
+ * reset @udev.  The end result is that a broken power session can be
+ * recovered and @udev will appear to persist across a loss of VBUS power.
+ *
+ * For example, if a host controller doesn't maintain VBUS suspend current
+ * during a system sleep or is reset when the system wakes up, all the USB
+ * power sessions below it will be broken.  This is especially troublesome
+ * for mass-storage devices containing mounted filesystems, since the
+ * device will appear to have disconnected and all the memory mappings
+ * to it will be lost.  Using the USB_PERSIST facility, the device can be
+ * made to appear as if it had not disconnected.
+ *
+ * This facility can be dangerous.  Although usb_reset_and_verify_device() makes
+ * every effort to insure that the same device is present after the
+ * reset as before, it cannot provide a 100% guarantee.  Furthermore it's
+ * quite possible for a device to remain unaltered but its media to be
+ * changed.  If the user replaces a flash memory card while the system is
+ * asleep, he will have only himself to blame when the filesystem on the
+ * new card is corrupted and the system crashes.
+ *
+ * Returns 0 on success, else negative errno.
+ */
+int usb_port_resume(struct usb_device *udev, pm_message_t msg)
+{
+	struct usb_hub	*hub = usb_hub_to_struct_hub(udev->parent);
+	struct usb_port *port_dev = hub->ports[udev->portnum  - 1];
+	int		port1 = udev->portnum;
+	int		status;
+	u16		portchange, portstatus;
+
+	if (!test_and_set_bit(port1, hub->child_usage_bits)) {
+		status = pm_runtime_get_sync(&port_dev->dev);
+		if (status < 0) {
+			dev_dbg(&udev->dev, "can't resume usb port, status %d\n",
+					status);
+			return status;
+		}
+	}
+
+	usb_lock_port(port_dev);
+
+	/* Skip the initial Clear-Suspend step for a remote wakeup */
+	status = hub_port_status(hub, port1, &portstatus, &portchange);
+	if (status == 0 && !port_is_suspended(hub, portstatus))
+		goto SuspendCleared;
+
+	/* see 7.1.7.7; affects power usage, but not budgeting */
+	if (hub_is_superspeed(hub->hdev))
+		status = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_U0);
+	else
+		status = usb_clear_port_feature(hub->hdev,
+				port1, USB_PORT_FEAT_SUSPEND);
+	if (status) {
+		dev_dbg(&port_dev->dev, "can't resume, status %d\n", status);
+	} else {
+		/* drive resume for USB_RESUME_TIMEOUT msec */
+		dev_dbg(&udev->dev, "usb %sresume\n",
+				(PMSG_IS_AUTO(msg) ? "auto-" : ""));
+		msleep(USB_RESUME_TIMEOUT);
+
+		/* Virtual root hubs can trigger on GET_PORT_STATUS to
+		 * stop resume signaling.  Then finish the resume
+		 * sequence.
+		 */
+		status = hub_port_status(hub, port1, &portstatus, &portchange);
+
+		/* TRSMRCY = 10 msec */
+		msleep(10);
+	}
+
+ SuspendCleared:
+	if (status == 0) {
+		udev->port_is_suspended = 0;
+		if (hub_is_superspeed(hub->hdev)) {
+			if (portchange & USB_PORT_STAT_C_LINK_STATE)
+				usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_PORT_LINK_STATE);
+		} else {
+			if (portchange & USB_PORT_STAT_C_SUSPEND)
+				usb_clear_port_feature(hub->hdev, port1,
+						USB_PORT_FEAT_C_SUSPEND);
+		}
+	}
+
+	if (udev->persist_enabled && hub_is_superspeed(hub->hdev))
+		status = wait_for_ss_port_enable(udev, hub, &port1, &portchange,
+				&portstatus);
+
+	status = check_port_resume_type(udev,
+			hub, port1, status, portchange, portstatus);
+	if (status == 0)
+		status = finish_port_resume(udev);
+	if (status < 0) {
+		dev_dbg(&udev->dev, "can't resume, status %d\n", status);
+		hub_port_logical_disconnect(hub, port1);
+	} else  {
+		/* Try to enable USB2 hardware LPM */
+		if (udev->usb2_hw_lpm_capable == 1)
+			usb_set_usb2_hardware_lpm(udev, 1);
+
+		/* Try to enable USB3 LTM and LPM */
+		usb_enable_ltm(udev);
+		usb_unlocked_enable_lpm(udev);
+	}
+
+	usb_unlock_port(port_dev);
+
+	return status;
+}
+
+int usb_remote_wakeup(struct usb_device *udev)
+{
+	int	status = 0;
+
+	usb_lock_device(udev);
+	if (udev->state == USB_STATE_SUSPENDED) {
+		dev_dbg(&udev->dev, "usb %sresume\n", "wakeup-");
+		status = usb_autoresume_device(udev);
+		if (status == 0) {
+			/* Let the drivers do their thing, then... */
+			usb_autosuspend_device(udev);
+		}
+	}
+	usb_unlock_device(udev);
+	return status;
+}
+
+/* Returns 1 if there was a remote wakeup and a connect status change. */
+static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
+		u16 portstatus, u16 portchange)
+		__must_hold(&port_dev->status_lock)
+{
+	struct usb_port *port_dev = hub->ports[port - 1];
+	struct usb_device *hdev;
+	struct usb_device *udev;
+	int connect_change = 0;
+	int ret;
+
+	hdev = hub->hdev;
+	udev = port_dev->child;
+	if (!hub_is_superspeed(hdev)) {
+		if (!(portchange & USB_PORT_STAT_C_SUSPEND))
+			return 0;
+		usb_clear_port_feature(hdev, port, USB_PORT_FEAT_C_SUSPEND);
+	} else {
+		if (!udev || udev->state != USB_STATE_SUSPENDED ||
+				 (portstatus & USB_PORT_STAT_LINK_STATE) !=
+				 USB_SS_PORT_LS_U0)
+			return 0;
+	}
+
+	if (udev) {
+		/* TRSMRCY = 10 msec */
+		msleep(10);
+
+		usb_unlock_port(port_dev);
+		ret = usb_remote_wakeup(udev);
+		usb_lock_port(port_dev);
+		if (ret < 0)
+			connect_change = 1;
+	} else {
+		ret = -ENODEV;
+		hub_port_disable(hub, port, 1);
+	}
+	dev_dbg(&port_dev->dev, "resume, status %d\n", ret);
+	return connect_change;
+}
+
+static int check_ports_changed(struct usb_hub *hub)
+{
+	int port1;
+
+	for (port1 = 1; port1 <= hub->hdev->maxchild; ++port1) {
+		u16 portstatus, portchange;
+		int status;
+
+		status = hub_port_status(hub, port1, &portstatus, &portchange);
+		if (!status && portchange)
+			return 1;
+	}
+	return 0;
+}
+
+static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
+{
+	struct usb_hub		*hub = usb_get_intfdata (intf);
+	struct usb_device	*hdev = hub->hdev;
+	unsigned		port1;
+	int			status;
+
+	/*
+	 * Warn if children aren't already suspended.
+	 * Also, add up the number of wakeup-enabled descendants.
+	 */
+	hub->wakeup_enabled_descendants = 0;
+	for (port1 = 1; port1 <= hdev->maxchild; port1++) {
+		struct usb_port *port_dev = hub->ports[port1 - 1];
+		struct usb_device *udev = port_dev->child;
+
+		if (udev && udev->can_submit) {
+			dev_warn(&port_dev->dev, "device %s not suspended yet\n",
+					dev_name(&udev->dev));
+			if (PMSG_IS_AUTO(msg))
+				return -EBUSY;
+		}
+		if (udev)
+			hub->wakeup_enabled_descendants +=
+					wakeup_enabled_descendants(udev);
+	}
+
+	if (hdev->do_remote_wakeup && hub->quirk_check_port_auto_suspend) {
+		/* check if there are changes pending on hub ports */
+		if (check_ports_changed(hub)) {
+			if (PMSG_IS_AUTO(msg))
+				return -EBUSY;
+			pm_wakeup_event(&hdev->dev, 2000);
+		}
+	}
+
+	if (hub_is_superspeed(hdev) && hdev->do_remote_wakeup) {
+		/* Enable hub to send remote wakeup for all ports. */
+		for (port1 = 1; port1 <= hdev->maxchild; port1++) {
+			status = set_port_feature(hdev,
+					port1 |
+					USB_PORT_FEAT_REMOTE_WAKE_CONNECT |
+					USB_PORT_FEAT_REMOTE_WAKE_DISCONNECT |
+					USB_PORT_FEAT_REMOTE_WAKE_OVER_CURRENT,
+					USB_PORT_FEAT_REMOTE_WAKE_MASK);
+		}
+	}
+
+	dev_dbg(&intf->dev, "%s\n", __func__);
+
+	/* stop hub_wq and related activity */
+	hub_quiesce(hub, HUB_SUSPEND);
+	return 0;
+}
+
+static int hub_resume(struct usb_interface *intf)
+{
+	struct usb_hub *hub = usb_get_intfdata(intf);
+
+	dev_dbg(&intf->dev, "%s\n", __func__);
+	hub_activate(hub, HUB_RESUME);
+	return 0;
+}
+
+static int hub_reset_resume(struct usb_interface *intf)
+{
+	struct usb_hub *hub = usb_get_intfdata(intf);
+
+	dev_dbg(&intf->dev, "%s\n", __func__);
+	hub_activate(hub, HUB_RESET_RESUME);
+	return 0;
+}
+
+/**
+ * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
+ * @rhdev: struct usb_device for the root hub
+ *
+ * The USB host controller driver calls this function when its root hub
+ * is resumed and Vbus power has been interrupted or the controller
+ * has been reset.  The routine marks @rhdev as having lost power.
+ * When the hub driver is resumed it will take notice and carry out
+ * power-session recovery for all the "USB-PERSIST"-enabled child devices;
+ * the others will be disconnected.
+ */
+void usb_root_hub_lost_power(struct usb_device *rhdev)
+{
+	dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
+	rhdev->reset_resume = 1;
+}
+EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
+
+static const char * const usb3_lpm_names[]  = {
+	"U0",
+	"U1",
+	"U2",
+	"U3",
+};
+
+/*
+ * Send a Set SEL control transfer to the device, prior to enabling
+ * device-initiated U1 or U2.  This lets the device know the exit latencies from
+ * the time the device initiates a U1 or U2 exit, to the time it will receive a
+ * packet from the host.
+ *
+ * This function will fail if the SEL or PEL values for udev are greater than
+ * the maximum allowed values for the link state to be enabled.
+ */
+static int usb_req_set_sel(struct usb_device *udev, enum usb3_link_state state)
+{
+	struct usb_set_sel_req *sel_values;
+	unsigned long long u1_sel;
+	unsigned long long u1_pel;
+	unsigned long long u2_sel;
+	unsigned long long u2_pel;
+	int ret;
+
+	if (udev->state != USB_STATE_CONFIGURED)
+		return 0;
+
+	/* Convert SEL and PEL stored in ns to us */
+	u1_sel = DIV_ROUND_UP(udev->u1_params.sel, 1000);
+	u1_pel = DIV_ROUND_UP(udev->u1_params.pel, 1000);
+	u2_sel = DIV_ROUND_UP(udev->u2_params.sel, 1000);
+	u2_pel = DIV_ROUND_UP(udev->u2_params.pel, 1000);
+
+	/*
+	 * Make sure that the calculated SEL and PEL values for the link
+	 * state we're enabling aren't bigger than the max SEL/PEL
+	 * value that will fit in the SET SEL control transfer.
+	 * Otherwise the device would get an incorrect idea of the exit
+	 * latency for the link state, and could start a device-initiated
+	 * U1/U2 when the exit latencies are too high.
+	 */
+	if ((state == USB3_LPM_U1 &&
+				(u1_sel > USB3_LPM_MAX_U1_SEL_PEL ||
+				 u1_pel > USB3_LPM_MAX_U1_SEL_PEL)) ||
+			(state == USB3_LPM_U2 &&
+			 (u2_sel > USB3_LPM_MAX_U2_SEL_PEL ||
+			  u2_pel > USB3_LPM_MAX_U2_SEL_PEL))) {
+		dev_dbg(&udev->dev, "Device-initiated %s disabled due to long SEL %llu us or PEL %llu us\n",
+				usb3_lpm_names[state], u1_sel, u1_pel);
+		return -EINVAL;
+	}
+
+	/*
+	 * If we're enabling device-initiated LPM for one link state,
+	 * but the other link state has a too high SEL or PEL value,
+	 * just set those values to the max in the Set SEL request.
+	 */
+	if (u1_sel > USB3_LPM_MAX_U1_SEL_PEL)
+		u1_sel = USB3_LPM_MAX_U1_SEL_PEL;
+
+	if (u1_pel > USB3_LPM_MAX_U1_SEL_PEL)
+		u1_pel = USB3_LPM_MAX_U1_SEL_PEL;
+
+	if (u2_sel > USB3_LPM_MAX_U2_SEL_PEL)
+		u2_sel = USB3_LPM_MAX_U2_SEL_PEL;
+
+	if (u2_pel > USB3_LPM_MAX_U2_SEL_PEL)
+		u2_pel = USB3_LPM_MAX_U2_SEL_PEL;
+
+	/*
+	 * usb_enable_lpm() can be called as part of a failed device reset,
+	 * which may be initiated by an error path of a mass storage driver.
+	 * Therefore, use GFP_NOIO.
+	 */
+	sel_values = kmalloc(sizeof *(sel_values), GFP_NOIO);
+	if (!sel_values)
+		return -ENOMEM;
+
+	sel_values->u1_sel = u1_sel;
+	sel_values->u1_pel = u1_pel;
+	sel_values->u2_sel = cpu_to_le16(u2_sel);
+	sel_values->u2_pel = cpu_to_le16(u2_pel);
+
+	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+			USB_REQ_SET_SEL,
+			USB_RECIP_DEVICE,
+			0, 0,
+			sel_values, sizeof *(sel_values),
+			USB_CTRL_SET_TIMEOUT);
+	kfree(sel_values);
+	return ret;
+}
+
+/*
+ * Enable or disable device-initiated U1 or U2 transitions.
+ */
+static int usb_set_device_initiated_lpm(struct usb_device *udev,
+		enum usb3_link_state state, bool enable)
+{
+	int ret;
+	int feature;
+
+	switch (state) {
+	case USB3_LPM_U1:
+		feature = USB_DEVICE_U1_ENABLE;
+		break;
+	case USB3_LPM_U2:
+		feature = USB_DEVICE_U2_ENABLE;
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't %s non-U1 or U2 state.\n",
+				__func__, enable ? "enable" : "disable");
+		return -EINVAL;
+	}
+
+	if (udev->state != USB_STATE_CONFIGURED) {
+		dev_dbg(&udev->dev, "%s: Can't %s %s state "
+				"for unconfigured device.\n",
+				__func__, enable ? "enable" : "disable",
+				usb3_lpm_names[state]);
+		return 0;
+	}
+
+	if (enable) {
+		/*
+		 * Now send the control transfer to enable device-initiated LPM
+		 * for either U1 or U2.
+		 */
+		ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE,
+				USB_RECIP_DEVICE,
+				feature,
+				0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	} else {
+		ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_CLEAR_FEATURE,
+				USB_RECIP_DEVICE,
+				feature,
+				0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	}
+	if (ret < 0) {
+		dev_warn(&udev->dev, "%s of device-initiated %s failed.\n",
+				enable ? "Enable" : "Disable",
+				usb3_lpm_names[state]);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int usb_set_lpm_timeout(struct usb_device *udev,
+		enum usb3_link_state state, int timeout)
+{
+	int ret;
+	int feature;
+
+	switch (state) {
+	case USB3_LPM_U1:
+		feature = USB_PORT_FEAT_U1_TIMEOUT;
+		break;
+	case USB3_LPM_U2:
+		feature = USB_PORT_FEAT_U2_TIMEOUT;
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't set timeout for non-U1 or U2 state.\n",
+				__func__);
+		return -EINVAL;
+	}
+
+	if (state == USB3_LPM_U1 && timeout > USB3_LPM_U1_MAX_TIMEOUT &&
+			timeout != USB3_LPM_DEVICE_INITIATED) {
+		dev_warn(&udev->dev, "Failed to set %s timeout to 0x%x, "
+				"which is a reserved value.\n",
+				usb3_lpm_names[state], timeout);
+		return -EINVAL;
+	}
+
+	ret = set_port_feature(udev->parent,
+			USB_PORT_LPM_TIMEOUT(timeout) | udev->portnum,
+			feature);
+	if (ret < 0) {
+		dev_warn(&udev->dev, "Failed to set %s timeout to 0x%x,"
+				"error code %i\n", usb3_lpm_names[state],
+				timeout, ret);
+		return -EBUSY;
+	}
+	if (state == USB3_LPM_U1)
+		udev->u1_params.timeout = timeout;
+	else
+		udev->u2_params.timeout = timeout;
+	return 0;
+}
+
+/*
+ * Enable the hub-initiated U1/U2 idle timeouts, and enable device-initiated
+ * U1/U2 entry.
+ *
+ * We will attempt to enable U1 or U2, but there are no guarantees that the
+ * control transfers to set the hub timeout or enable device-initiated U1/U2
+ * will be successful.
+ *
+ * If we cannot set the parent hub U1/U2 timeout, we attempt to let the xHCI
+ * driver know about it.  If that call fails, it should be harmless, and just
+ * take up more slightly more bus bandwidth for unnecessary U1/U2 exit latency.
+ */
+static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	int timeout, ret;
+	__u8 u1_mel = udev->bos->ss_cap->bU1devExitLat;
+	__le16 u2_mel = udev->bos->ss_cap->bU2DevExitLat;
+
+	/* If the device says it doesn't have *any* exit latency to come out of
+	 * U1 or U2, it's probably lying.  Assume it doesn't implement that link
+	 * state.
+	 */
+	if ((state == USB3_LPM_U1 && u1_mel == 0) ||
+			(state == USB3_LPM_U2 && u2_mel == 0))
+		return;
+
+	/*
+	 * First, let the device know about the exit latencies
+	 * associated with the link state we're about to enable.
+	 */
+	ret = usb_req_set_sel(udev, state);
+	if (ret < 0) {
+		dev_warn(&udev->dev, "Set SEL for device-initiated %s failed.\n",
+				usb3_lpm_names[state]);
+		return;
+	}
+
+	/* We allow the host controller to set the U1/U2 timeout internally
+	 * first, so that it can change its schedule to account for the
+	 * additional latency to send data to a device in a lower power
+	 * link state.
+	 */
+	timeout = hcd->driver->enable_usb3_lpm_timeout(hcd, udev, state);
+
+	/* xHCI host controller doesn't want to enable this LPM state. */
+	if (timeout == 0)
+		return;
+
+	if (timeout < 0) {
+		dev_warn(&udev->dev, "Could not enable %s link state, "
+				"xHCI error %i.\n", usb3_lpm_names[state],
+				timeout);
+		return;
+	}
+
+	if (usb_set_lpm_timeout(udev, state, timeout))
+		/* If we can't set the parent hub U1/U2 timeout,
+		 * device-initiated LPM won't be allowed either, so let the xHCI
+		 * host know that this link state won't be enabled.
+		 */
+		hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state);
+
+	/* Only a configured device will accept the Set Feature U1/U2_ENABLE */
+	else if (udev->actconfig)
+		usb_set_device_initiated_lpm(udev, state, true);
+
+}
+
+/*
+ * Disable the hub-initiated U1/U2 idle timeouts, and disable device-initiated
+ * U1/U2 entry.
+ *
+ * If this function returns -EBUSY, the parent hub will still allow U1/U2 entry.
+ * If zero is returned, the parent will not allow the link to go into U1/U2.
+ *
+ * If zero is returned, device-initiated U1/U2 entry may still be enabled, but
+ * it won't have an effect on the bus link state because the parent hub will
+ * still disallow device-initiated U1/U2 entry.
+ *
+ * If zero is returned, the xHCI host controller may still think U1/U2 entry is
+ * possible.  The result will be slightly more bus bandwidth will be taken up
+ * (to account for U1/U2 exit latency), but it should be harmless.
+ */
+static int usb_disable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	switch (state) {
+	case USB3_LPM_U1:
+	case USB3_LPM_U2:
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't disable non-U1 or U2 state.\n",
+				__func__);
+		return -EINVAL;
+	}
+
+	if (usb_set_lpm_timeout(udev, state, 0))
+		return -EBUSY;
+
+	usb_set_device_initiated_lpm(udev, state, false);
+
+	if (hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state))
+		dev_warn(&udev->dev, "Could not disable xHCI %s timeout, "
+				"bus schedule bandwidth may be impacted.\n",
+				usb3_lpm_names[state]);
+	return 0;
+}
+
+/*
+ * Disable hub-initiated and device-initiated U1 and U2 entry.
+ * Caller must own the bandwidth_mutex.
+ *
+ * This will call usb_enable_lpm() on failure, which will decrement
+ * lpm_disable_count, and will re-enable LPM if lpm_disable_count reaches zero.
+ */
+int usb_disable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd;
+
+	if (!udev || !udev->parent ||
+			udev->speed != USB_SPEED_SUPER ||
+			!udev->lpm_capable ||
+			udev->state < USB_STATE_DEFAULT)
+		return 0;
+
+	hcd = bus_to_hcd(udev->bus);
+	if (!hcd || !hcd->driver->disable_usb3_lpm_timeout)
+		return 0;
+
+	udev->lpm_disable_count++;
+	if ((udev->u1_params.timeout == 0 && udev->u2_params.timeout == 0))
+		return 0;
+
+	/* If LPM is enabled, attempt to disable it. */
+	if (usb_disable_link_state(hcd, udev, USB3_LPM_U1))
+		goto enable_lpm;
+	if (usb_disable_link_state(hcd, udev, USB3_LPM_U2))
+		goto enable_lpm;
+
+	return 0;
+
+enable_lpm:
+	usb_enable_lpm(udev);
+	return -EBUSY;
+}
+EXPORT_SYMBOL_GPL(usb_disable_lpm);
+
+/* Grab the bandwidth_mutex before calling usb_disable_lpm() */
+int usb_unlocked_disable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+	int ret;
+
+	if (!hcd)
+		return -EINVAL;
+
+	mutex_lock(hcd->bandwidth_mutex);
+	ret = usb_disable_lpm(udev);
+	mutex_unlock(hcd->bandwidth_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_unlocked_disable_lpm);
+
+/*
+ * Attempt to enable device-initiated and hub-initiated U1 and U2 entry.  The
+ * xHCI host policy may prevent U1 or U2 from being enabled.
+ *
+ * Other callers may have disabled link PM, so U1 and U2 entry will be disabled
+ * until the lpm_disable_count drops to zero.  Caller must own the
+ * bandwidth_mutex.
+ */
+void usb_enable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd;
+
+	if (!udev || !udev->parent ||
+			udev->speed != USB_SPEED_SUPER ||
+			!udev->lpm_capable ||
+			udev->state < USB_STATE_DEFAULT)
+		return;
+
+	udev->lpm_disable_count--;
+	hcd = bus_to_hcd(udev->bus);
+	/* Double check that we can both enable and disable LPM.
+	 * Device must be configured to accept set feature U1/U2 timeout.
+	 */
+	if (!hcd || !hcd->driver->enable_usb3_lpm_timeout ||
+			!hcd->driver->disable_usb3_lpm_timeout)
+		return;
+
+	if (udev->lpm_disable_count > 0)
+		return;
+
+	usb_enable_link_state(hcd, udev, USB3_LPM_U1);
+	usb_enable_link_state(hcd, udev, USB3_LPM_U2);
+}
+EXPORT_SYMBOL_GPL(usb_enable_lpm);
+
+/* Grab the bandwidth_mutex before calling usb_enable_lpm() */
+void usb_unlocked_enable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	if (!hcd)
+		return;
+
+	mutex_lock(hcd->bandwidth_mutex);
+	usb_enable_lpm(udev);
+	mutex_unlock(hcd->bandwidth_mutex);
+}
+EXPORT_SYMBOL_GPL(usb_unlocked_enable_lpm);
+
+
+#else	/* CONFIG_PM */
+
+#define hub_suspend		NULL
+#define hub_resume		NULL
+#define hub_reset_resume	NULL
+
+int usb_disable_lpm(struct usb_device *udev)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_disable_lpm);
+
+void usb_enable_lpm(struct usb_device *udev) { }
+EXPORT_SYMBOL_GPL(usb_enable_lpm);
+
+int usb_unlocked_disable_lpm(struct usb_device *udev)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_unlocked_disable_lpm);
+
+void usb_unlocked_enable_lpm(struct usb_device *udev) { }
+EXPORT_SYMBOL_GPL(usb_unlocked_enable_lpm);
+
+int usb_disable_ltm(struct usb_device *udev)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_disable_ltm);
+
+void usb_enable_ltm(struct usb_device *udev) { }
+EXPORT_SYMBOL_GPL(usb_enable_ltm);
+
+static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
+		u16 portstatus, u16 portchange)
+{
+	return 0;
+}
+
+#endif	/* CONFIG_PM */
+
+
+/* USB 2.0 spec, 7.1.7.3 / fig 7-29:
+ *
+ * Between connect detection and reset signaling there must be a delay
+ * of 100ms at least for debounce and power-settling.  The corresponding
+ * timer shall restart whenever the downstream port detects a disconnect.
+ *
+ * Apparently there are some bluetooth and irda-dongles and a number of
+ * low-speed devices for which this debounce period may last over a second.
+ * Not covered by the spec - but easy to deal with.
+ *
+ * This implementation uses a 1500ms total debounce timeout; if the
+ * connection isn't stable by then it returns -ETIMEDOUT.  It checks
+ * every 25ms for transient disconnects.  When the port status has been
+ * unchanged for 100ms it returns the port status.
+ */
+int hub_port_debounce(struct usb_hub *hub, int port1, bool must_be_connected)
+{
+	int ret;
+	u16 portchange, portstatus;
+	unsigned connection = 0xffff;
+	int total_time, stable_time = 0;
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+
+	for (total_time = 0; ; total_time += HUB_DEBOUNCE_STEP) {
+		ret = hub_port_status(hub, port1, &portstatus, &portchange);
+		if (ret < 0)
+			return ret;
+
+		if (!(portchange & USB_PORT_STAT_C_CONNECTION) &&
+		     (portstatus & USB_PORT_STAT_CONNECTION) == connection) {
+			if (!must_be_connected ||
+			     (connection == USB_PORT_STAT_CONNECTION))
+				stable_time += HUB_DEBOUNCE_STEP;
+			if (stable_time >= HUB_DEBOUNCE_STABLE)
+				break;
+		} else {
+			stable_time = 0;
+			connection = portstatus & USB_PORT_STAT_CONNECTION;
+		}
+
+		if (portchange & USB_PORT_STAT_C_CONNECTION) {
+			usb_clear_port_feature(hub->hdev, port1,
+					USB_PORT_FEAT_C_CONNECTION);
+		}
+
+		if (total_time >= HUB_DEBOUNCE_TIMEOUT)
+			break;
+		msleep(HUB_DEBOUNCE_STEP);
+	}
+
+	dev_dbg(&port_dev->dev, "debounce total %dms stable %dms status 0x%x\n",
+			total_time, stable_time, portstatus);
+
+	if (stable_time < HUB_DEBOUNCE_STABLE)
+		return -ETIMEDOUT;
+	return portstatus;
+}
+
+void usb_ep0_reinit(struct usb_device *udev)
+{
+	usb_disable_endpoint(udev, 0 + USB_DIR_IN, true);
+	usb_disable_endpoint(udev, 0 + USB_DIR_OUT, true);
+	usb_enable_endpoint(udev, &udev->ep0, true);
+}
+EXPORT_SYMBOL_GPL(usb_ep0_reinit);
+
+#define usb_sndaddr0pipe()	(PIPE_CONTROL << 30)
+#define usb_rcvaddr0pipe()	((PIPE_CONTROL << 30) | USB_DIR_IN)
+
+static int hub_set_address(struct usb_device *udev, int devnum)
+{
+	int retval;
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	/*
+	 * The host controller will choose the device address,
+	 * instead of the core having chosen it earlier
+	 */
+	if (!hcd->driver->address_device && devnum <= 1)
+		return -EINVAL;
+	if (udev->state == USB_STATE_ADDRESS)
+		return 0;
+	if (udev->state != USB_STATE_DEFAULT)
+		return -EINVAL;
+	if (hcd->driver->address_device)
+		retval = hcd->driver->address_device(hcd, udev);
+	else
+		retval = usb_control_msg(udev, usb_sndaddr0pipe(),
+				USB_REQ_SET_ADDRESS, 0, devnum, 0,
+				NULL, 0, USB_CTRL_SET_TIMEOUT);
+	if (retval == 0) {
+		update_devnum(udev, devnum);
+		/* Device now using proper address. */
+		usb_set_device_state(udev, USB_STATE_ADDRESS);
+		usb_ep0_reinit(udev);
+	}
+	return retval;
+}
+
+/*
+ * There are reports of USB 3.0 devices that say they support USB 2.0 Link PM
+ * when they're plugged into a USB 2.0 port, but they don't work when LPM is
+ * enabled.
+ *
+ * Only enable USB 2.0 Link PM if the port is internal (hardwired), or the
+ * device says it supports the new USB 2.0 Link PM errata by setting the BESL
+ * support bit in the BOS descriptor.
+ */
+static void hub_set_initial_usb2_lpm_policy(struct usb_device *udev)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(udev->parent);
+	int connect_type = USB_PORT_CONNECT_TYPE_UNKNOWN;
+
+	if (!udev->usb2_hw_lpm_capable)
+		return;
+
+	if (hub)
+		connect_type = hub->ports[udev->portnum - 1]->connect_type;
+
+	if ((udev->bos->ext_cap->bmAttributes & cpu_to_le32(USB_BESL_SUPPORT)) ||
+			connect_type == USB_PORT_CONNECT_TYPE_HARD_WIRED) {
+		udev->usb2_hw_lpm_allowed = 1;
+		usb_set_usb2_hardware_lpm(udev, 1);
+	}
+}
+
+static int hub_enable_device(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	if (!hcd->driver->enable_device)
+		return 0;
+	if (udev->state == USB_STATE_ADDRESS)
+		return 0;
+	if (udev->state != USB_STATE_DEFAULT)
+		return -EINVAL;
+
+	return hcd->driver->enable_device(hcd, udev);
+}
+
+/* Reset device, (re)assign address, get device descriptor.
+ * Device connection must be stable, no more debouncing needed.
+ * Returns device in USB_STATE_ADDRESS, except on error.
+ *
+ * If this is called for an already-existing device (as part of
+ * usb_reset_and_verify_device), the caller must own the device lock and
+ * the port lock.  For a newly detected device that is not accessible
+ * through any global pointers, it's not necessary to lock the device,
+ * but it is still necessary to lock the port.
+ */
+static int
+hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
+		int retry_counter)
+{
+	struct usb_device	*hdev = hub->hdev;
+	struct usb_hcd		*hcd = bus_to_hcd(hdev->bus);
+	int			i, j, retval;
+	unsigned		delay = HUB_SHORT_RESET_TIME;
+	enum usb_device_speed	oldspeed = udev->speed;
+	const char		*speed;
+	int			devnum = udev->devnum;
+
+	/* root hub ports have a slightly longer reset period
+	 * (from USB 2.0 spec, section 7.1.7.5)
+	 */
+	if (!hdev->parent) {
+		delay = HUB_ROOT_RESET_TIME;
+		if (port1 == hdev->bus->otg_port)
+			hdev->bus->b_hnp_enable = 0;
+	}
+
+	/* Some low speed devices have problems with the quick delay, so */
+	/*  be a bit pessimistic with those devices. RHbug #23670 */
+	if (oldspeed == USB_SPEED_LOW)
+		delay = HUB_LONG_RESET_TIME;
+
+	mutex_lock(&hdev->bus->usb_address0_mutex);
+
+	/* 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, false);
+	if (retval < 0)		/* error or disconnect */
+		goto fail;
+	/* success, speed is known */
+
+	retval = -ENODEV;
+
+	if (oldspeed != USB_SPEED_UNKNOWN && oldspeed != udev->speed) {
+		dev_dbg(&udev->dev, "device reset changed speed!\n");
+		goto fail;
+	}
+	oldspeed = udev->speed;
+
+	/* USB 2.0 section 5.5.3 talks about ep0 maxpacket ...
+	 * it's fixed size except for full speed devices.
+	 * For Wireless USB devices, ep0 max packet is always 512 (tho
+	 * reported as 0xff in the device descriptor). WUSB1.0[4.8.1].
+	 */
+	switch (udev->speed) {
+	case USB_SPEED_SUPER:
+	case USB_SPEED_WIRELESS:	/* fixed at 512 */
+		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512);
+		break;
+	case USB_SPEED_HIGH:		/* fixed at 64 */
+		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
+		break;
+	case USB_SPEED_FULL:		/* 8, 16, 32, or 64 */
+		/* to determine the ep0 maxpacket size, try to read
+		 * the device descriptor to get bMaxPacketSize0 and
+		 * then correct our initial guess.
+		 */
+		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
+		break;
+	case USB_SPEED_LOW:		/* fixed at 8 */
+		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(8);
+		break;
+	default:
+		goto fail;
+	}
+
+	if (udev->speed == USB_SPEED_WIRELESS)
+		speed = "variable speed Wireless";
+	else
+		speed = usb_speed_string(udev->speed);
+
+	if (udev->speed != USB_SPEED_SUPER)
+		dev_info(&udev->dev,
+				"%s %s USB device number %d using %s\n",
+				(udev->config) ? "reset" : "new", speed,
+				devnum, udev->bus->controller->driver->name);
+
+	/* Set up TT records, if needed  */
+	if (hdev->tt) {
+		udev->tt = hdev->tt;
+		udev->ttport = hdev->ttport;
+	} else if (udev->speed != USB_SPEED_HIGH
+			&& hdev->speed == USB_SPEED_HIGH) {
+		if (!hub->tt.hub) {
+			dev_err(&udev->dev, "parent hub has no TT\n");
+			retval = -EINVAL;
+			goto fail;
+		}
+		udev->tt = &hub->tt;
+		udev->ttport = port1;
+	}
+
+	/* Why interleave GET_DESCRIPTOR and SET_ADDRESS this way?
+	 * Because device hardware and firmware is sometimes buggy in
+	 * this area, and this is how Linux has done it for ages.
+	 * Change it cautiously.
+	 *
+	 * NOTE:  If use_new_scheme() is true we will start by issuing
+	 * a 64-byte GET_DESCRIPTOR request.  This is what Windows does,
+	 * so it may help with some non-standards-compliant devices.
+	 * Otherwise we start with SET_ADDRESS and then try to read the
+	 * first 8 bytes of the device descriptor to get the ep0 maxpacket
+	 * value.
+	 */
+	for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
+		bool did_new_scheme = false;
+
+		if (use_new_scheme(udev, retry_counter)) {
+			struct usb_device_descriptor *buf;
+			int r = 0;
+
+			did_new_scheme = true;
+			retval = hub_enable_device(udev);
+			if (retval < 0) {
+				dev_err(&udev->dev,
+					"hub failed to enable device, error %d\n",
+					retval);
+				goto fail;
+			}
+
+#define GET_DESCRIPTOR_BUFSIZE	64
+			buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO);
+			if (!buf) {
+				retval = -ENOMEM;
+				continue;
+			}
+
+			/* Retry on all errors; some devices are flakey.
+			 * 255 is for WUSB devices, we actually need to use
+			 * 512 (WUSB1.0[4.8.1]).
+			 */
+			for (j = 0; j < 3; ++j) {
+				buf->bMaxPacketSize0 = 0;
+				r = usb_control_msg(udev, usb_rcvaddr0pipe(),
+					USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
+					USB_DT_DEVICE << 8, 0,
+					buf, GET_DESCRIPTOR_BUFSIZE,
+					initial_descriptor_timeout);
+				switch (buf->bMaxPacketSize0) {
+				case 8: case 16: case 32: case 64: case 255:
+					if (buf->bDescriptorType ==
+							USB_DT_DEVICE) {
+						r = 0;
+						break;
+					}
+					/* FALL THROUGH */
+				default:
+					if (r == 0)
+						r = -EPROTO;
+					break;
+				}
+				if (r == 0)
+					break;
+			}
+			udev->descriptor.bMaxPacketSize0 =
+					buf->bMaxPacketSize0;
+			kfree(buf);
+
+			retval = hub_port_reset(hub, port1, udev, delay, false);
+			if (retval < 0)		/* error or disconnect */
+				goto fail;
+			if (oldspeed != udev->speed) {
+				dev_dbg(&udev->dev,
+					"device reset changed speed!\n");
+				retval = -ENODEV;
+				goto fail;
+			}
+			if (r) {
+				if (r != -ENODEV)
+					dev_err(&udev->dev, "device descriptor read/64, error %d\n",
+							r);
+				retval = -EMSGSIZE;
+				continue;
+			}
+#undef GET_DESCRIPTOR_BUFSIZE
+		}
+
+		/*
+		 * If device is WUSB, we already assigned an
+		 * unauthorized address in the Connect Ack sequence;
+		 * authorization will assign the final address.
+		 */
+		if (udev->wusb == 0) {
+			for (j = 0; j < SET_ADDRESS_TRIES; ++j) {
+				retval = hub_set_address(udev, devnum);
+				if (retval >= 0)
+					break;
+				msleep(200);
+			}
+			if (retval < 0) {
+				if (retval != -ENODEV)
+					dev_err(&udev->dev, "device not accepting address %d, error %d\n",
+							devnum, retval);
+				goto fail;
+			}
+			if (udev->speed == USB_SPEED_SUPER) {
+				devnum = udev->devnum;
+				dev_info(&udev->dev,
+						"%s SuperSpeed USB device number %d using %s\n",
+						(udev->config) ? "reset" : "new",
+						devnum, udev->bus->controller->driver->name);
+			}
+
+			/* cope with hardware quirkiness:
+			 *  - let SET_ADDRESS settle, some device hardware wants it
+			 *  - read ep0 maxpacket even for high and low speed,
+			 */
+			msleep(10);
+			/* use_new_scheme() checks the speed which may have
+			 * changed since the initial look so we cache the result
+			 * in did_new_scheme
+			 */
+			if (did_new_scheme)
+				break;
+		}
+
+		retval = usb_get_device_descriptor(udev, 8);
+		if (retval < 8) {
+			if (retval != -ENODEV)
+				dev_err(&udev->dev,
+					"device descriptor read/8, error %d\n",
+					retval);
+			if (retval >= 0)
+				retval = -EMSGSIZE;
+		} else {
+			retval = 0;
+			break;
+		}
+	}
+	if (retval)
+		goto fail;
+
+	/*
+	 * Some superspeed devices have finished the link training process
+	 * and attached to a superspeed hub port, but the device descriptor
+	 * got from those devices show they aren't superspeed devices. Warm
+	 * reset the port attached by the devices can fix them.
+	 */
+	if ((udev->speed == USB_SPEED_SUPER) &&
+			(le16_to_cpu(udev->descriptor.bcdUSB) < 0x0300)) {
+		dev_err(&udev->dev, "got a wrong device descriptor, "
+				"warm reset device\n");
+		hub_port_reset(hub, port1, udev,
+				HUB_BH_RESET_TIME, true);
+		retval = -EINVAL;
+		goto fail;
+	}
+
+	if (udev->descriptor.bMaxPacketSize0 == 0xff ||
+			udev->speed == USB_SPEED_SUPER)
+		i = 512;
+	else
+		i = udev->descriptor.bMaxPacketSize0;
+	if (usb_endpoint_maxp(&udev->ep0.desc) != i) {
+		if (udev->speed == USB_SPEED_LOW ||
+				!(i == 8 || i == 16 || i == 32 || i == 64)) {
+			dev_err(&udev->dev, "Invalid ep0 maxpacket: %d\n", i);
+			retval = -EMSGSIZE;
+			goto fail;
+		}
+		if (udev->speed == USB_SPEED_FULL)
+			dev_dbg(&udev->dev, "ep0 maxpacket = %d\n", i);
+		else
+			dev_warn(&udev->dev, "Using ep0 maxpacket: %d\n", i);
+		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(i);
+		usb_ep0_reinit(udev);
+	}
+
+	retval = usb_get_device_descriptor(udev, USB_DT_DEVICE_SIZE);
+	if (retval < (signed)sizeof(udev->descriptor)) {
+		if (retval != -ENODEV)
+			dev_err(&udev->dev, "device descriptor read/all, error %d\n",
+					retval);
+		if (retval >= 0)
+			retval = -ENOMSG;
+		goto fail;
+	}
+
+	if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
+		retval = usb_get_bos_descriptor(udev);
+		if (!retval) {
+			udev->lpm_capable = usb_device_supports_lpm(udev);
+			usb_set_lpm_parameters(udev);
+		}
+	}
+
+	retval = 0;
+	/* notify HCD that we have a device connected and addressed */
+	if (hcd->driver->update_device)
+		hcd->driver->update_device(hcd, udev);
+	hub_set_initial_usb2_lpm_policy(udev);
+fail:
+	if (retval) {
+		hub_port_disable(hub, port1, 0);
+		update_devnum(udev, devnum);	/* for disconnect processing */
+	}
+	mutex_unlock(&hdev->bus->usb_address0_mutex);
+	return retval;
+}
+
+static void
+check_highspeed (struct usb_hub *hub, struct usb_device *udev, int port1)
+{
+	struct usb_qualifier_descriptor	*qual;
+	int				status;
+
+	if (udev->quirks & USB_QUIRK_DEVICE_QUALIFIER)
+		return;
+
+	qual = kmalloc (sizeof *qual, GFP_KERNEL);
+	if (qual == NULL)
+		return;
+
+	status = usb_get_descriptor (udev, USB_DT_DEVICE_QUALIFIER, 0,
+			qual, sizeof *qual);
+	if (status == sizeof *qual) {
+		dev_info(&udev->dev, "not running at top speed; "
+			"connect to a high speed hub\n");
+		/* hub LEDs are probably harder to miss than syslog */
+		if (hub->has_indicators) {
+			hub->indicator[port1-1] = INDICATOR_GREEN_BLINK;
+			queue_delayed_work(system_power_efficient_wq,
+					&hub->leds, 0);
+		}
+	}
+	kfree(qual);
+}
+
+static unsigned
+hub_power_remaining (struct usb_hub *hub)
+{
+	struct usb_device *hdev = hub->hdev;
+	int remaining;
+	int port1;
+
+	if (!hub->limited_power)
+		return 0;
+
+	remaining = hdev->bus_mA - hub->descriptor->bHubContrCurrent;
+	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
+		struct usb_port *port_dev = hub->ports[port1 - 1];
+		struct usb_device *udev = port_dev->child;
+		unsigned unit_load;
+		int delta;
+
+		if (!udev)
+			continue;
+		if (hub_is_superspeed(udev))
+			unit_load = 150;
+		else
+			unit_load = 100;
+
+		/*
+		 * Unconfigured devices may not use more than one unit load,
+		 * or 8mA for OTG ports
+		 */
+		if (udev->actconfig)
+			delta = usb_get_max_power(udev, udev->actconfig);
+		else if (port1 != udev->bus->otg_port || hdev->parent)
+			delta = unit_load;
+		else
+			delta = 8;
+		if (delta > hub->mA_per_port)
+			dev_warn(&port_dev->dev, "%dmA is over %umA budget!\n",
+					delta, hub->mA_per_port);
+		remaining -= delta;
+	}
+	if (remaining < 0) {
+		dev_warn(hub->intfdev, "%dmA over power budget!\n",
+			-remaining);
+		remaining = 0;
+	}
+	return remaining;
+}
+
+static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
+		u16 portchange)
+{
+	int status, i;
+	unsigned unit_load;
+	struct usb_device *hdev = hub->hdev;
+	struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	struct usb_device *udev = port_dev->child;
+	static int unreliable_port = -1;
+
+	/* Disconnect any existing devices under this port */
+	if (udev) {
+		if (hcd->usb_phy && !hdev->parent)
+			usb_phy_notify_disconnect(hcd->usb_phy, udev->speed);
+		usb_disconnect(&port_dev->child);
+	}
+
+	/* We can forget about a "removed" device when there's a physical
+	 * disconnect or the connect status changes.
+	 */
+	if (!(portstatus & USB_PORT_STAT_CONNECTION) ||
+			(portchange & USB_PORT_STAT_C_CONNECTION))
+		clear_bit(port1, hub->removed_bits);
+
+	if (portchange & (USB_PORT_STAT_C_CONNECTION |
+				USB_PORT_STAT_C_ENABLE)) {
+		status = hub_port_debounce_be_stable(hub, port1);
+		if (status < 0) {
+			if (status != -ENODEV &&
+				port1 != unreliable_port &&
+				printk_ratelimit())
+				dev_err(&port_dev->dev, "connect-debounce failed\n");
+			portstatus &= ~USB_PORT_STAT_CONNECTION;
+			unreliable_port = port1;
+		} else {
+			portstatus = status;
+		}
+	}
+
+	/* Return now if debouncing failed or nothing is connected or
+	 * the device was "removed".
+	 */
+	if (!(portstatus & USB_PORT_STAT_CONNECTION) ||
+			test_bit(port1, hub->removed_bits)) {
+
+		/*
+		 * maybe switch power back on (e.g. root hub was reset)
+		 * but only if the port isn't owned by someone else.
+		 */
+		if (hub_is_port_power_switchable(hub)
+				&& !port_is_power_on(hub, portstatus)
+				&& !port_dev->port_owner)
+			set_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
+
+		if (portstatus & USB_PORT_STAT_ENABLE)
+			goto done;
+		return;
+	}
+	if (hub_is_superspeed(hub->hdev))
+		unit_load = 150;
+	else
+		unit_load = 100;
+
+	status = 0;
+	for (i = 0; i < SET_CONFIG_TRIES; i++) {
+
+		/* reallocate for each attempt, since references
+		 * to the previous one can escape in various ways
+		 */
+		udev = usb_alloc_dev(hdev, hdev->bus, port1);
+		if (!udev) {
+			dev_err(&port_dev->dev,
+					"couldn't allocate usb_device\n");
+			goto done;
+		}
+
+		usb_set_device_state(udev, USB_STATE_POWERED);
+		udev->bus_mA = hub->mA_per_port;
+		udev->level = hdev->level + 1;
+		udev->wusb = hub_is_wusb(hub);
+
+		/* Only USB 3.0 devices are connected to SuperSpeed hubs. */
+		if (hub_is_superspeed(hub->hdev))
+			udev->speed = USB_SPEED_SUPER;
+		else
+			udev->speed = USB_SPEED_UNKNOWN;
+
+		choose_devnum(udev);
+		if (udev->devnum <= 0) {
+			status = -ENOTCONN;	/* Don't retry */
+			goto loop;
+		}
+
+		/* reset (non-USB 3.0 devices) and get descriptor */
+		usb_lock_port(port_dev);
+		status = hub_port_init(hub, udev, port1, i);
+		usb_unlock_port(port_dev);
+		if (status < 0)
+			goto loop;
+
+		usb_detect_quirks(udev);
+		if (udev->quirks & USB_QUIRK_DELAY_INIT)
+			msleep(1000);
+
+		/* consecutive bus-powered hubs aren't reliable; they can
+		 * violate the voltage drop budget.  if the new child has
+		 * a "powered" LED, users should notice we didn't enable it
+		 * (without reading syslog), even without per-port LEDs
+		 * on the parent.
+		 */
+		if (udev->descriptor.bDeviceClass == USB_CLASS_HUB
+				&& udev->bus_mA <= unit_load) {
+			u16	devstat;
+
+			status = usb_get_status(udev, USB_RECIP_DEVICE, 0,
+					&devstat);
+			if (status) {
+				dev_dbg(&udev->dev, "get status %d ?\n", status);
+				goto loop_disable;
+			}
+			if ((devstat & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
+				dev_err(&udev->dev,
+					"can't connect bus-powered hub "
+					"to this port\n");
+				if (hub->has_indicators) {
+					hub->indicator[port1-1] =
+						INDICATOR_AMBER_BLINK;
+					queue_delayed_work(
+						system_power_efficient_wq,
+						&hub->leds, 0);
+				}
+				status = -ENOTCONN;	/* Don't retry */
+				goto loop_disable;
+			}
+		}
+
+		/* check for devices running slower than they could */
+		if (le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0200
+				&& udev->speed == USB_SPEED_FULL
+				&& highspeed_hubs != 0)
+			check_highspeed (hub, udev, port1);
+
+		/* Store the parent's children[] pointer.  At this point
+		 * udev becomes globally accessible, although presumably
+		 * no one will look at it until hdev is unlocked.
+		 */
+		status = 0;
+
+		mutex_lock(&usb_port_peer_mutex);
+
+		/* We mustn't add new devices if the parent hub has
+		 * been disconnected; we would race with the
+		 * recursively_mark_NOTATTACHED() routine.
+		 */
+		spin_lock_irq(&device_state_lock);
+		if (hdev->state == USB_STATE_NOTATTACHED)
+			status = -ENOTCONN;
+		else
+			port_dev->child = udev;
+		spin_unlock_irq(&device_state_lock);
+		mutex_unlock(&usb_port_peer_mutex);
+
+		/* Run it through the hoops (find a driver, etc) */
+		if (!status) {
+			status = usb_new_device(udev);
+			if (status) {
+				mutex_lock(&usb_port_peer_mutex);
+				spin_lock_irq(&device_state_lock);
+				port_dev->child = NULL;
+				spin_unlock_irq(&device_state_lock);
+				mutex_unlock(&usb_port_peer_mutex);
+			} else {
+				if (hcd->usb_phy && !hdev->parent)
+					usb_phy_notify_connect(hcd->usb_phy,
+							udev->speed);
+			}
+		}
+
+		if (status)
+			goto loop_disable;
+
+		status = hub_power_remaining(hub);
+		if (status)
+			dev_dbg(hub->intfdev, "%dmA power budget left\n", status);
+
+		return;
+
+loop_disable:
+		hub_port_disable(hub, port1, 1);
+loop:
+		usb_ep0_reinit(udev);
+		release_devnum(udev);
+		hub_free_dev(udev);
+		usb_put_dev(udev);
+		if ((status == -ENOTCONN) || (status == -ENOTSUPP))
+			break;
+	}
+	if (hub->hdev->parent ||
+			!hcd->driver->port_handed_over ||
+			!(hcd->driver->port_handed_over)(hcd, port1)) {
+		if (status != -ENOTCONN && status != -ENODEV)
+			dev_err(&port_dev->dev,
+					"unable to enumerate USB device\n");
+	}
+
+done:
+	hub_port_disable(hub, port1, 1);
+	if (hcd->driver->relinquish_port && !hub->hdev->parent)
+		hcd->driver->relinquish_port(hcd, port1);
+
+}
+
+/* Handle physical or logical connection change events.
+ * This routine is called when:
+ *	a port connection-change occurs;
+ *	a port enable-change occurs (often caused by EMI);
+ *	usb_reset_and_verify_device() encounters changed descriptors (as from
+ *		a firmware download)
+ * caller already locked the hub
+ */
+static void hub_port_connect_change(struct usb_hub *hub, int port1,
+					u16 portstatus, u16 portchange)
+		__must_hold(&port_dev->status_lock)
+{
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	struct usb_device *udev = port_dev->child;
+	int status = -ENODEV;
+
+	dev_dbg(&port_dev->dev, "status %04x, change %04x, %s\n", portstatus,
+			portchange, portspeed(hub, portstatus));
+
+	if (hub->has_indicators) {
+		set_port_led(hub, port1, HUB_LED_AUTO);
+		hub->indicator[port1-1] = INDICATOR_AUTO;
+	}
+
+#ifdef	CONFIG_USB_OTG
+	/* during HNP, don't repeat the debounce */
+	if (hub->hdev->bus->is_b_host)
+		portchange &= ~(USB_PORT_STAT_C_CONNECTION |
+				USB_PORT_STAT_C_ENABLE);
+#endif
+
+	/* Try to resuscitate an existing device */
+	if ((portstatus & USB_PORT_STAT_CONNECTION) && udev &&
+			udev->state != USB_STATE_NOTATTACHED) {
+		if (portstatus & USB_PORT_STAT_ENABLE) {
+			status = 0;		/* Nothing to do */
+#ifdef CONFIG_PM
+		} else if (udev->state == USB_STATE_SUSPENDED &&
+				udev->persist_enabled) {
+			/* For a suspended device, treat this as a
+			 * remote wakeup event.
+			 */
+			usb_unlock_port(port_dev);
+			status = usb_remote_wakeup(udev);
+			usb_lock_port(port_dev);
+#endif
+		} else {
+			/* Don't resuscitate */;
+		}
+	}
+	clear_bit(port1, hub->change_bits);
+
+	/* successfully revalidated the connection */
+	if (status == 0)
+		return;
+
+	usb_unlock_port(port_dev);
+	hub_port_connect(hub, port1, portstatus, portchange);
+	usb_lock_port(port_dev);
+}
+
+static void port_event(struct usb_hub *hub, int port1)
+		__must_hold(&port_dev->status_lock)
+{
+	int connect_change;
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	struct usb_device *udev = port_dev->child;
+	struct usb_device *hdev = hub->hdev;
+	u16 portstatus, portchange;
+
+	connect_change = test_bit(port1, hub->change_bits);
+	clear_bit(port1, hub->event_bits);
+	clear_bit(port1, hub->wakeup_bits);
+
+	if (hub_port_status(hub, port1, &portstatus, &portchange) < 0)
+		return;
+
+	if (portchange & USB_PORT_STAT_C_CONNECTION) {
+		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
+		connect_change = 1;
+	}
+
+	if (portchange & USB_PORT_STAT_C_ENABLE) {
+		if (!connect_change)
+			dev_dbg(&port_dev->dev, "enable change, status %08x\n",
+					portstatus);
+		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
+
+		/*
+		 * EM interference sometimes causes badly shielded USB devices
+		 * to be shutdown by the hub, this hack enables them again.
+		 * Works at least with mouse driver.
+		 */
+		if (!(portstatus & USB_PORT_STAT_ENABLE)
+		    && !connect_change && udev) {
+			dev_err(&port_dev->dev, "disabled by hub (EMI?), re-enabling...\n");
+			connect_change = 1;
+		}
+	}
+
+	if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
+		u16 status = 0, unused;
+
+		dev_dbg(&port_dev->dev, "over-current change\n");
+		usb_clear_port_feature(hdev, port1,
+				USB_PORT_FEAT_C_OVER_CURRENT);
+		msleep(100);	/* Cool down */
+		hub_power_on(hub, true);
+		hub_port_status(hub, port1, &status, &unused);
+		if (status & USB_PORT_STAT_OVERCURRENT)
+			dev_err(&port_dev->dev, "over-current condition\n");
+	}
+
+	if (portchange & USB_PORT_STAT_C_RESET) {
+		dev_dbg(&port_dev->dev, "reset change\n");
+		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_RESET);
+	}
+	if ((portchange & USB_PORT_STAT_C_BH_RESET)
+	    && hub_is_superspeed(hdev)) {
+		dev_dbg(&port_dev->dev, "warm reset change\n");
+		usb_clear_port_feature(hdev, port1,
+				USB_PORT_FEAT_C_BH_PORT_RESET);
+	}
+	if (portchange & USB_PORT_STAT_C_LINK_STATE) {
+		dev_dbg(&port_dev->dev, "link state change\n");
+		usb_clear_port_feature(hdev, port1,
+				USB_PORT_FEAT_C_PORT_LINK_STATE);
+	}
+	if (portchange & USB_PORT_STAT_C_CONFIG_ERROR) {
+		dev_warn(&port_dev->dev, "config error\n");
+		usb_clear_port_feature(hdev, port1,
+				USB_PORT_FEAT_C_PORT_CONFIG_ERROR);
+	}
+
+	/* skip port actions that require the port to be powered on */
+	if (!pm_runtime_active(&port_dev->dev))
+		return;
+
+	if (hub_handle_remote_wakeup(hub, port1, portstatus, portchange))
+		connect_change = 1;
+
+	/*
+	 * Warm reset a USB3 protocol port if it's in
+	 * SS.Inactive state.
+	 */
+	if (hub_port_warm_reset_required(hub, port1, portstatus)) {
+		dev_dbg(&port_dev->dev, "do warm reset\n");
+		if (!udev || !(portstatus & USB_PORT_STAT_CONNECTION)
+				|| udev->state == USB_STATE_NOTATTACHED) {
+			if (hub_port_reset(hub, port1, NULL,
+					HUB_BH_RESET_TIME, true) < 0)
+				hub_port_disable(hub, port1, 1);
+		} else {
+			usb_unlock_port(port_dev);
+			usb_lock_device(udev);
+			usb_reset_device(udev);
+			usb_unlock_device(udev);
+			usb_lock_port(port_dev);
+			connect_change = 0;
+		}
+	}
+
+	if (connect_change)
+		hub_port_connect_change(hub, port1, portstatus, portchange);
+}
+
+static void hub_event(struct work_struct *work)
+{
+	struct usb_device *hdev;
+	struct usb_interface *intf;
+	struct usb_hub *hub;
+	struct device *hub_dev;
+	u16 hubstatus;
+	u16 hubchange;
+	int i, ret;
+
+	hub = container_of(work, struct usb_hub, events);
+	hdev = hub->hdev;
+	hub_dev = hub->intfdev;
+	intf = to_usb_interface(hub_dev);
+
+	dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
+			hdev->state, hdev->maxchild,
+			/* NOTE: expects max 15 ports... */
+			(u16) hub->change_bits[0],
+			(u16) hub->event_bits[0]);
+
+	/* Lock the device, then check to see if we were
+	 * disconnected while waiting for the lock to succeed. */
+	usb_lock_device(hdev);
+	if (unlikely(hub->disconnected))
+		goto out_hdev_lock;
+
+	/* If the hub has died, clean up after it */
+	if (hdev->state == USB_STATE_NOTATTACHED) {
+		hub->error = -ENODEV;
+		hub_quiesce(hub, HUB_DISCONNECT);
+		goto out_hdev_lock;
+	}
+
+	/* Autoresume */
+	ret = usb_autopm_get_interface(intf);
+	if (ret) {
+		dev_dbg(hub_dev, "Can't autoresume: %d\n", ret);
+		goto out_hdev_lock;
+	}
+
+	/* If this is an inactive hub, do nothing */
+	if (hub->quiescing)
+		goto out_autopm;
+
+	if (hub->error) {
+		dev_dbg(hub_dev, "resetting for error %d\n", hub->error);
+
+		ret = usb_reset_device(hdev);
+		if (ret) {
+			dev_dbg(hub_dev, "error resetting hub: %d\n", ret);
+			goto out_autopm;
+		}
+
+		hub->nerrors = 0;
+		hub->error = 0;
+	}
+
+	/* deal with port status changes */
+	for (i = 1; i <= hdev->maxchild; i++) {
+		struct usb_port *port_dev = hub->ports[i - 1];
+
+		if (test_bit(i, hub->event_bits)
+				|| test_bit(i, hub->change_bits)
+				|| test_bit(i, hub->wakeup_bits)) {
+			/*
+			 * The get_noresume and barrier ensure that if
+			 * the port was in the process of resuming, we
+			 * flush that work and keep the port active for
+			 * the duration of the port_event().  However,
+			 * if the port is runtime pm suspended
+			 * (powered-off), we leave it in that state, run
+			 * an abbreviated port_event(), and move on.
+			 */
+			pm_runtime_get_noresume(&port_dev->dev);
+			pm_runtime_barrier(&port_dev->dev);
+			usb_lock_port(port_dev);
+			port_event(hub, i);
+			usb_unlock_port(port_dev);
+			pm_runtime_put_sync(&port_dev->dev);
+		}
+	}
+
+	/* deal with hub status changes */
+	if (test_and_clear_bit(0, hub->event_bits) == 0)
+		;	/* do nothing */
+	else if (hub_hub_status(hub, &hubstatus, &hubchange) < 0)
+		dev_err(hub_dev, "get_hub_status failed\n");
+	else {
+		if (hubchange & HUB_CHANGE_LOCAL_POWER) {
+			dev_dbg(hub_dev, "power change\n");
+			clear_hub_feature(hdev, C_HUB_LOCAL_POWER);
+			if (hubstatus & HUB_STATUS_LOCAL_POWER)
+				/* FIXME: Is this always true? */
+				hub->limited_power = 1;
+			else
+				hub->limited_power = 0;
+		}
+		if (hubchange & HUB_CHANGE_OVERCURRENT) {
+			u16 status = 0;
+			u16 unused;
+
+			dev_dbg(hub_dev, "over-current change\n");
+			clear_hub_feature(hdev, C_HUB_OVER_CURRENT);
+			msleep(500);	/* Cool down */
+			hub_power_on(hub, true);
+			hub_hub_status(hub, &status, &unused);
+			if (status & HUB_STATUS_OVERCURRENT)
+				dev_err(hub_dev, "over-current condition\n");
+		}
+	}
+
+out_autopm:
+	/* Balance the usb_autopm_get_interface() above */
+	usb_autopm_put_interface_no_suspend(intf);
+out_hdev_lock:
+	usb_unlock_device(hdev);
+
+	/* Balance the stuff in kick_hub_wq() and allow autosuspend */
+	usb_autopm_put_interface(intf);
+	kref_put(&hub->kref, hub_release);
+}
+
+static const struct usb_device_id hub_id_table[] = {
+    { .match_flags = USB_DEVICE_ID_MATCH_VENDOR
+			| USB_DEVICE_ID_MATCH_INT_CLASS,
+      .idVendor = USB_VENDOR_GENESYS_LOGIC,
+      .bInterfaceClass = USB_CLASS_HUB,
+      .driver_info = HUB_QUIRK_CHECK_PORT_AUTOSUSPEND},
+    { .match_flags = USB_DEVICE_ID_MATCH_DEV_CLASS,
+      .bDeviceClass = USB_CLASS_HUB},
+    { .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS,
+      .bInterfaceClass = USB_CLASS_HUB},
+    { }						/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE (usb, hub_id_table);
+
+static struct usb_driver hub_driver = {
+	.name =		"hub",
+	.probe =	hub_probe,
+	.disconnect =	hub_disconnect,
+	.suspend =	hub_suspend,
+	.resume =	hub_resume,
+	.reset_resume =	hub_reset_resume,
+	.pre_reset =	hub_pre_reset,
+	.post_reset =	hub_post_reset,
+	.unlocked_ioctl = hub_ioctl,
+	.id_table =	hub_id_table,
+	.supports_autosuspend =	1,
+};
+
+int usb_hub_init(void)
+{
+	if (usb_register(&hub_driver) < 0) {
+		printk(KERN_ERR "%s: can't register hub driver\n",
+			usbcore_name);
+		return -1;
+	}
+
+	/*
+	 * The workqueue needs to be freezable to avoid interfering with
+	 * USB-PERSIST port handover. Otherwise it might see that a full-speed
+	 * device was gone before the EHCI controller had handed its port
+	 * over to the companion full-speed controller.
+	 */
+	hub_wq = alloc_workqueue("usb_hub_wq", WQ_FREEZABLE, 0);
+	if (hub_wq)
+		return 0;
+
+	/* Fall through if kernel_thread failed */
+	usb_deregister(&hub_driver);
+	pr_err("%s: can't allocate workqueue for usb hub\n", usbcore_name);
+
+	return -1;
+}
+
+void usb_hub_cleanup(void)
+{
+	destroy_workqueue(hub_wq);
+
+	/*
+	 * Hub resources are freed for us by usb_deregister. It calls
+	 * usb_driver_purge on every device which in turn calls that
+	 * devices disconnect function if it is using this driver.
+	 * The hub_disconnect function takes care of releasing the
+	 * individual hub resources. -greg
+	 */
+	usb_deregister(&hub_driver);
+} /* usb_hub_cleanup() */
+
+static int descriptors_changed(struct usb_device *udev,
+		struct usb_device_descriptor *old_device_descriptor,
+		struct usb_host_bos *old_bos)
+{
+	int		changed = 0;
+	unsigned	index;
+	unsigned	serial_len = 0;
+	unsigned	len;
+	unsigned	old_length;
+	int		length;
+	char		*buf;
+
+	if (memcmp(&udev->descriptor, old_device_descriptor,
+			sizeof(*old_device_descriptor)) != 0)
+		return 1;
+
+	if ((old_bos && !udev->bos) || (!old_bos && udev->bos))
+		return 1;
+	if (udev->bos) {
+		len = le16_to_cpu(udev->bos->desc->wTotalLength);
+		if (len != le16_to_cpu(old_bos->desc->wTotalLength))
+			return 1;
+		if (memcmp(udev->bos->desc, old_bos->desc, len))
+			return 1;
+	}
+
+	/* Since the idVendor, idProduct, and bcdDevice values in the
+	 * device descriptor haven't changed, we will assume the
+	 * Manufacturer and Product strings haven't changed either.
+	 * But the SerialNumber string could be different (e.g., a
+	 * different flash card of the same brand).
+	 */
+	if (udev->serial)
+		serial_len = strlen(udev->serial) + 1;
+
+	len = serial_len;
+	for (index = 0; index < udev->descriptor.bNumConfigurations; index++) {
+		old_length = le16_to_cpu(udev->config[index].desc.wTotalLength);
+		len = max(len, old_length);
+	}
+
+	buf = kmalloc(len, GFP_NOIO);
+	if (buf == NULL) {
+		dev_err(&udev->dev, "no mem to re-read configs after reset\n");
+		/* assume the worst */
+		return 1;
+	}
+	for (index = 0; index < udev->descriptor.bNumConfigurations; index++) {
+		old_length = le16_to_cpu(udev->config[index].desc.wTotalLength);
+		length = usb_get_descriptor(udev, USB_DT_CONFIG, index, buf,
+				old_length);
+		if (length != old_length) {
+			dev_dbg(&udev->dev, "config index %d, error %d\n",
+					index, length);
+			changed = 1;
+			break;
+		}
+		if (memcmp (buf, udev->rawdescriptors[index], old_length)
+				!= 0) {
+			dev_dbg(&udev->dev, "config index %d changed (#%d)\n",
+				index,
+				((struct usb_config_descriptor *) buf)->
+					bConfigurationValue);
+			changed = 1;
+			break;
+		}
+	}
+
+	if (!changed && serial_len) {
+		length = usb_string(udev, udev->descriptor.iSerialNumber,
+				buf, serial_len);
+		if (length + 1 != serial_len) {
+			dev_dbg(&udev->dev, "serial string error %d\n",
+					length);
+			changed = 1;
+		} else if (memcmp(buf, udev->serial, length) != 0) {
+			dev_dbg(&udev->dev, "serial string changed\n");
+			changed = 1;
+		}
+	}
+
+	kfree(buf);
+	return changed;
+}
+
+/**
+ * usb_reset_and_verify_device - perform a USB port reset to reinitialize a device
+ * @udev: device to reset (not in SUSPENDED or NOTATTACHED state)
+ *
+ * WARNING - don't use this routine to reset a composite device
+ * (one with multiple interfaces owned by separate drivers)!
+ * Use usb_reset_device() instead.
+ *
+ * Do a port reset, reassign the device's address, and establish its
+ * former operating configuration.  If the reset fails, or the device's
+ * descriptors change from their values before the reset, or the original
+ * configuration and altsettings cannot be restored, a flag will be set
+ * telling hub_wq to pretend the device has been disconnected and then
+ * re-connected.  All drivers will be unbound, and the device will be
+ * re-enumerated and probed all over again.
+ *
+ * Return: 0 if the reset succeeded, -ENODEV if the device has been
+ * flagged for logical disconnection, or some other negative error code
+ * if the reset wasn't even attempted.
+ *
+ * Note:
+ * The caller must own the device lock and the port lock, the latter is
+ * taken by usb_reset_device().  For example, it's safe to use
+ * usb_reset_device() from a driver probe() routine after downloading
+ * new firmware.  For calls that might not occur during probe(), drivers
+ * should lock the device using usb_lock_device_for_reset().
+ *
+ * Locking exception: This routine may also be called from within an
+ * autoresume handler.  Such usage won't conflict with other tasks
+ * holding the device lock because these tasks should always call
+ * usb_autopm_resume_device(), thereby preventing any unwanted
+ * autoresume.  The autoresume handler is expected to have already
+ * acquired the port lock before calling this routine.
+ */
+static int usb_reset_and_verify_device(struct usb_device *udev)
+{
+	struct usb_device		*parent_hdev = udev->parent;
+	struct usb_hub			*parent_hub;
+	struct usb_hcd			*hcd = bus_to_hcd(udev->bus);
+	struct usb_device_descriptor	descriptor = udev->descriptor;
+	struct usb_host_bos		*bos;
+	int				i, j, ret = 0;
+	int				port1 = udev->portnum;
+
+	if (udev->state == USB_STATE_NOTATTACHED ||
+			udev->state == USB_STATE_SUSPENDED) {
+		dev_dbg(&udev->dev, "device reset not allowed in state %d\n",
+				udev->state);
+		return -EINVAL;
+	}
+
+	if (!parent_hdev)
+		return -EISDIR;
+
+	parent_hub = usb_hub_to_struct_hub(parent_hdev);
+
+	/* Disable USB2 hardware LPM.
+	 * It will be re-enabled by the enumeration process.
+	 */
+	if (udev->usb2_hw_lpm_enabled == 1)
+		usb_set_usb2_hardware_lpm(udev, 0);
+
+	bos = udev->bos;
+	udev->bos = NULL;
+
+	/* Disable LPM and LTM while we reset the device and reinstall the alt
+	 * settings.  Device-initiated LPM settings, and system exit latency
+	 * settings are cleared when the device is reset, so we have to set
+	 * them up again.
+	 */
+	ret = usb_unlocked_disable_lpm(udev);
+	if (ret) {
+		dev_err(&udev->dev, "%s Failed to disable LPM\n.", __func__);
+		goto re_enumerate;
+	}
+	ret = usb_disable_ltm(udev);
+	if (ret) {
+		dev_err(&udev->dev, "%s Failed to disable LTM\n.",
+				__func__);
+		goto re_enumerate;
+	}
+
+	for (i = 0; i < SET_CONFIG_TRIES; ++i) {
+
+		/* ep0 maxpacket size may change; let the HCD know about it.
+		 * Other endpoints will be handled by re-enumeration. */
+		usb_ep0_reinit(udev);
+		ret = hub_port_init(parent_hub, udev, port1, i);
+		if (ret >= 0 || ret == -ENOTCONN || ret == -ENODEV)
+			break;
+	}
+
+	if (ret < 0)
+		goto re_enumerate;
+
+	/* Device might have changed firmware (DFU or similar) */
+	if (descriptors_changed(udev, &descriptor, bos)) {
+		dev_info(&udev->dev, "device firmware changed\n");
+		udev->descriptor = descriptor;	/* for disconnect() calls */
+		goto re_enumerate;
+	}
+
+	/* Restore the device's previous configuration */
+	if (!udev->actconfig)
+		goto done;
+
+	mutex_lock(hcd->bandwidth_mutex);
+	ret = usb_hcd_alloc_bandwidth(udev, udev->actconfig, NULL, NULL);
+	if (ret < 0) {
+		dev_warn(&udev->dev,
+				"Busted HC?  Not enough HCD resources for "
+				"old configuration.\n");
+		mutex_unlock(hcd->bandwidth_mutex);
+		goto re_enumerate;
+	}
+	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+			USB_REQ_SET_CONFIGURATION, 0,
+			udev->actconfig->desc.bConfigurationValue, 0,
+			NULL, 0, USB_CTRL_SET_TIMEOUT);
+	if (ret < 0) {
+		dev_err(&udev->dev,
+			"can't restore configuration #%d (error=%d)\n",
+			udev->actconfig->desc.bConfigurationValue, ret);
+		mutex_unlock(hcd->bandwidth_mutex);
+		goto re_enumerate;
+	}
+	mutex_unlock(hcd->bandwidth_mutex);
+	usb_set_device_state(udev, USB_STATE_CONFIGURED);
+
+	/* Put interfaces back into the same altsettings as before.
+	 * Don't bother to send the Set-Interface request for interfaces
+	 * that were already in altsetting 0; besides being unnecessary,
+	 * many devices can't handle it.  Instead just reset the host-side
+	 * endpoint state.
+	 */
+	for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
+		struct usb_host_config *config = udev->actconfig;
+		struct usb_interface *intf = config->interface[i];
+		struct usb_interface_descriptor *desc;
+
+		desc = &intf->cur_altsetting->desc;
+		if (desc->bAlternateSetting == 0) {
+			usb_disable_interface(udev, intf, true);
+			usb_enable_interface(udev, intf, true);
+			ret = 0;
+		} else {
+			/* Let the bandwidth allocation function know that this
+			 * device has been reset, and it will have to use
+			 * alternate setting 0 as the current alternate setting.
+			 */
+			intf->resetting_device = 1;
+			ret = usb_set_interface(udev, desc->bInterfaceNumber,
+					desc->bAlternateSetting);
+			intf->resetting_device = 0;
+		}
+		if (ret < 0) {
+			dev_err(&udev->dev, "failed to restore interface %d "
+				"altsetting %d (error=%d)\n",
+				desc->bInterfaceNumber,
+				desc->bAlternateSetting,
+				ret);
+			goto re_enumerate;
+		}
+		/* Resetting also frees any allocated streams */
+		for (j = 0; j < intf->cur_altsetting->desc.bNumEndpoints; j++)
+			intf->cur_altsetting->endpoint[j].streams = 0;
+	}
+
+done:
+	/* Now that the alt settings are re-installed, enable LTM and LPM. */
+	usb_set_usb2_hardware_lpm(udev, 1);
+	usb_unlocked_enable_lpm(udev);
+	usb_enable_ltm(udev);
+	usb_release_bos_descriptor(udev);
+	udev->bos = bos;
+	return 0;
+
+re_enumerate:
+	/* LPM state doesn't matter when we're about to destroy the device. */
+	hub_port_logical_disconnect(parent_hub, port1);
+	usb_release_bos_descriptor(udev);
+	udev->bos = bos;
+	return -ENODEV;
+}
+
+/**
+ * usb_reset_device - warn interface drivers and perform a USB port reset
+ * @udev: device to reset (not in SUSPENDED or NOTATTACHED state)
+ *
+ * Warns all drivers bound to registered interfaces (using their pre_reset
+ * method), performs the port reset, and then lets the drivers know that
+ * the reset is over (using their post_reset method).
+ *
+ * Return: The same as for usb_reset_and_verify_device().
+ *
+ * Note:
+ * The caller must own the device lock.  For example, it's safe to use
+ * this from a driver probe() routine after downloading new firmware.
+ * For calls that might not occur during probe(), drivers should lock
+ * the device using usb_lock_device_for_reset().
+ *
+ * If an interface is currently being probed or disconnected, we assume
+ * its driver knows how to handle resets.  For all other interfaces,
+ * if the driver doesn't have pre_reset and post_reset methods then
+ * we attempt to unbind it and rebind afterward.
+ */
+int usb_reset_device(struct usb_device *udev)
+{
+	int ret;
+	int i;
+	unsigned int noio_flag;
+	struct usb_port *port_dev;
+	struct usb_host_config *config = udev->actconfig;
+	struct usb_hub *hub = usb_hub_to_struct_hub(udev->parent);
+
+	if (udev->state == USB_STATE_NOTATTACHED ||
+			udev->state == USB_STATE_SUSPENDED) {
+		dev_dbg(&udev->dev, "device reset not allowed in state %d\n",
+				udev->state);
+		return -EINVAL;
+	}
+
+	if (!udev->parent) {
+		/* this requires hcd-specific logic; see ohci_restart() */
+		dev_dbg(&udev->dev, "%s for root hub!\n", __func__);
+		return -EISDIR;
+	}
+
+	port_dev = hub->ports[udev->portnum - 1];
+
+	/*
+	 * Don't allocate memory with GFP_KERNEL in current
+	 * context to avoid possible deadlock if usb mass
+	 * storage interface or usbnet interface(iSCSI case)
+	 * is included in current configuration. The easist
+	 * approach is to do it for every device reset,
+	 * because the device 'memalloc_noio' flag may have
+	 * not been set before reseting the usb device.
+	 */
+	noio_flag = memalloc_noio_save();
+
+	/* Prevent autosuspend during the reset */
+	usb_autoresume_device(udev);
+
+	if (config) {
+		for (i = 0; i < config->desc.bNumInterfaces; ++i) {
+			struct usb_interface *cintf = config->interface[i];
+			struct usb_driver *drv;
+			int unbind = 0;
+
+			if (cintf->dev.driver) {
+				drv = to_usb_driver(cintf->dev.driver);
+				if (drv->pre_reset && drv->post_reset)
+					unbind = (drv->pre_reset)(cintf);
+				else if (cintf->condition ==
+						USB_INTERFACE_BOUND)
+					unbind = 1;
+				if (unbind)
+					usb_forced_unbind_intf(cintf);
+			}
+		}
+	}
+
+	usb_lock_port(port_dev);
+	ret = usb_reset_and_verify_device(udev);
+	usb_unlock_port(port_dev);
+
+	if (config) {
+		for (i = config->desc.bNumInterfaces - 1; i >= 0; --i) {
+			struct usb_interface *cintf = config->interface[i];
+			struct usb_driver *drv;
+			int rebind = cintf->needs_binding;
+
+			if (!rebind && cintf->dev.driver) {
+				drv = to_usb_driver(cintf->dev.driver);
+				if (drv->post_reset)
+					rebind = (drv->post_reset)(cintf);
+				else if (cintf->condition ==
+						USB_INTERFACE_BOUND)
+					rebind = 1;
+				if (rebind)
+					cintf->needs_binding = 1;
+			}
+		}
+		usb_unbind_and_rebind_marked_interfaces(udev);
+	}
+
+	usb_autosuspend_device(udev);
+	memalloc_noio_restore(noio_flag);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_reset_device);
+
+
+/**
+ * usb_queue_reset_device - Reset a USB device from an atomic context
+ * @iface: USB interface belonging to the device to reset
+ *
+ * This function can be used to reset a USB device from an atomic
+ * context, where usb_reset_device() won't work (as it blocks).
+ *
+ * Doing a reset via this method is functionally equivalent to calling
+ * usb_reset_device(), except for the fact that it is delayed to a
+ * workqueue. This means that any drivers bound to other interfaces
+ * might be unbound, as well as users from usbfs in user space.
+ *
+ * Corner cases:
+ *
+ * - Scheduling two resets at the same time from two different drivers
+ *   attached to two different interfaces of the same device is
+ *   possible; depending on how the driver attached to each interface
+ *   handles ->pre_reset(), the second reset might happen or not.
+ *
+ * - If the reset is delayed so long that the interface is unbound from
+ *   its driver, the reset will be skipped.
+ *
+ * - This function can be called during .probe().  It can also be called
+ *   during .disconnect(), but doing so is pointless because the reset
+ *   will not occur.  If you really want to reset the device during
+ *   .disconnect(), call usb_reset_device() directly -- but watch out
+ *   for nested unbinding issues!
+ */
+void usb_queue_reset_device(struct usb_interface *iface)
+{
+	if (schedule_work(&iface->reset_ws))
+		usb_get_intf(iface);
+}
+EXPORT_SYMBOL_GPL(usb_queue_reset_device);
+
+/**
+ * usb_hub_find_child - Get the pointer of child device
+ * attached to the port which is specified by @port1.
+ * @hdev: USB device belonging to the usb hub
+ * @port1: port num to indicate which port the child device
+ *	is attached to.
+ *
+ * USB drivers call this function to get hub's child device
+ * pointer.
+ *
+ * Return: %NULL if input param is invalid and
+ * child's usb_device pointer if non-NULL.
+ */
+struct usb_device *usb_hub_find_child(struct usb_device *hdev,
+		int port1)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+
+	if (port1 < 1 || port1 > hdev->maxchild)
+		return NULL;
+	return hub->ports[port1 - 1]->child;
+}
+EXPORT_SYMBOL_GPL(usb_hub_find_child);
+
+void usb_hub_adjust_deviceremovable(struct usb_device *hdev,
+		struct usb_hub_descriptor *desc)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+	enum usb_port_connect_type connect_type;
+	int i;
+
+	if (!hub)
+		return;
+
+	if (!hub_is_superspeed(hdev)) {
+		for (i = 1; i <= hdev->maxchild; i++) {
+			struct usb_port *port_dev = hub->ports[i - 1];
+
+			connect_type = port_dev->connect_type;
+			if (connect_type == USB_PORT_CONNECT_TYPE_HARD_WIRED) {
+				u8 mask = 1 << (i%8);
+
+				if (!(desc->u.hs.DeviceRemovable[i/8] & mask)) {
+					dev_dbg(&port_dev->dev, "DeviceRemovable is changed to 1 according to platform information.\n");
+					desc->u.hs.DeviceRemovable[i/8]	|= mask;
+				}
+			}
+		}
+	} else {
+		u16 port_removable = le16_to_cpu(desc->u.ss.DeviceRemovable);
+
+		for (i = 1; i <= hdev->maxchild; i++) {
+			struct usb_port *port_dev = hub->ports[i - 1];
+
+			connect_type = port_dev->connect_type;
+			if (connect_type == USB_PORT_CONNECT_TYPE_HARD_WIRED) {
+				u16 mask = 1 << i;
+
+				if (!(port_removable & mask)) {
+					dev_dbg(&port_dev->dev, "DeviceRemovable is changed to 1 according to platform information.\n");
+					port_removable |= mask;
+				}
+			}
+		}
+
+		desc->u.ss.DeviceRemovable = cpu_to_le16(port_removable);
+	}
+}
+
+#ifdef CONFIG_ACPI
+/**
+ * usb_get_hub_port_acpi_handle - Get the usb port's acpi handle
+ * @hdev: USB device belonging to the usb hub
+ * @port1: port num of the port
+ *
+ * Return: Port's acpi handle if successful, %NULL if params are
+ * invalid.
+ */
+acpi_handle usb_get_hub_port_acpi_handle(struct usb_device *hdev,
+	int port1)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+
+	if (!hub)
+		return NULL;
+
+	return ACPI_HANDLE(&hub->ports[port1 - 1]->dev);
+}
+#endif