drivers/usb/core/hub.c - kernel/msm-4.19 - Gitiles

 /*
  * 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/kthread.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
 #include <linux/random.h>
 #include <linux/pm_qos.h>

 #include <asm/uaccess.h>
 #include <asm/byteorder.h>

 #include "hub.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);

 /* khubd's worklist and its lock */
 static DEFINE_SPINLOCK(hub_event_lock);
 static LIST_HEAD(hub_event_list);	/* List of hubs needing servicing */

 /* Wakes up khubd */
 static DECLARE_WAIT_QUEUE_HEAD(khubd_wait);

 static struct task_struct *khubd_task;

 /* 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 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]);
 }

 static 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_khubd(struct usb_hub *hub)
 {
 	unsigned long	flags;

 	spin_lock_irqsave(&hub_event_lock, flags);
 	if (!hub->disconnected && list_empty(&hub->event_list)) {
 		list_add_tail(&hub->event_list, &hub_event_list);

 		/* Suppress autosuspend until khubd runs */
 		usb_autopm_get_interface_no_resume(
 				to_usb_interface(hub->intfdev));
 		wake_up(&khubd_wait);
 	}
 	spin_unlock_irqrestore(&hub_event_lock, flags);
 }

 void usb_kick_khubd(struct usb_device *hdev)
 {
 	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);

 	if (hub)
 		kick_khubd(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_khubd(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 khubd 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 khubd figure it out */
 	kick_khubd(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 khubd 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 khubd 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
 	 * khubd reactivates the port later (timer, SRP, etc).
 	 * Powerdown must be optional, because of reset/DFU.
 	 */

 	set_bit(port1, hub->change_bits);
 	kick_khubd(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, khubd 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 khubd 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 khubd 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 khubd
 			 * 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 khubd */
 			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 khubd do them
 	 * one at a time later on.
 	 *
 	 * If any port-status changes do occur during this delay, khubd
 	 * 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_khubd(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);

 	/* khubd 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 khubd 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 khubd
 	 * 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_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;

 	/* Take the hub off the event list and don't let it be added again */
 	spin_lock_irq(&hub_event_lock);
 	if (!list_empty(&hub->event_list)) {
 		list_del_init(&hub->event_list);
 		usb_autopm_put_interface_no_suspend(intf);
 	}
 	hub->disconnected = 1;
 	spin_unlock_irq(&hub_event_lock);

 	/* 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_RUNTIME
 	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);
 	INIT_LIST_HEAD(&hub->event_list);
 	hub->intfdev = &intf->dev;
 	hub->hdev = hdev;
 	INIT_DELAYED_WORK(&hub->leds, led_work);
 	INIT_DELAYED_WORK(&hub->init_work, NULL);
 	usb_get_intf(intf);

 	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->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;

 	/* If khubd ever becomes multithreaded, this will need a lock */
 	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;
 	}
 }

 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

 #ifdef	CONFIG_USB_OTG
 #include "otg_whitelist.h"
 #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;
 				}
 			}
 		}
 	}

 	if (!is_targeted(udev)) {

 		/* Maybe it can talk to us, though we can't talk to it.
 		 * (Includes HNP test device.)
 		 */
 		if (udev->bus->b_hnp_enable || udev->bus->is_b_host) {
 			err = usb_port_suspend(udev, PMSG_SUSPEND);
 			if (err < 0)
 				dev_dbg(&udev->dev, "HNP fail, %d\n", err);
 		}
 		err = -ENOTSUPP;
 		goto fail;
 	}
 fail:
 #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;

 	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;

 	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);

 	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;

 	/*
 	 * Platform firmware may have populated an alternative value for
 	 * removable.  If the parent port has a known connect_type use
 	 * that instead.
 	 */
 	switch (hub->ports[udev->portnum - 1]->connect_type) {
 	case USB_PORT_CONNECT_TYPE_HOT_PLUG:
 		udev->removable = USB_DEVICE_REMOVABLE;
 		break;
 	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
 		udev->removable = USB_DEVICE_FIXED;
 		break;
 	default: /* use what was set above */
 		break;
 	}
 }

 /**
  * 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;
 	}
 	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);
 }

 static int hub_port_reset(struct usb_hub *hub, int port1,
 			struct usb_device *udev, unsigned int delay, bool warm);

 /* 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;
 }

 static void hub_port_finish_reset(struct usb_hub *hub, int port1,
 			struct usb_device *udev, int *status)
 {
 	switch (*status) {
 	case 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);
 		}
 		/* FALL THROUGH */
 	case -ENOTCONN:
 	case -ENODEV:
 		usb_clear_port_feature(hub->hdev,
 				port1, USB_PORT_FEAT_C_RESET);
 		if (hub_is_superspeed(hub->hdev)) {
 			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 (udev)
 			usb_set_device_state(udev, *status
 					? USB_STATE_NOTATTACHED
 					: USB_STATE_DEFAULT);
 		break;
 	}
 }

 /* 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.
 		 */
 		status = hub_port_status(hub, port1,
 					&portstatus, &portchange);
 		if (status < 0)
 			goto done;

 		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) {
 			hub_port_finish_reset(hub, port1, udev, &status);

 			if (!hub_is_superspeed(hub->hdev))
 				goto done;

 			/*
 			 * 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 (!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, unsigned portchange, unsigned portstatus)
 {
 	struct usb_port *port_dev = hub->ports[port1 - 1];

 	/* 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) ||
 			!(portstatus & USB_PORT_STAT_CONNECTION)) {
 		if (status >= 0)
 			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 khubd
  * 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 khubd 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 at least 20 msec */
 		dev_dbg(&udev->dev, "usb %sresume\n",
 				(PMSG_IS_AUTO(msg) ? "auto-" : ""));
 		msleep(25);

 		/* 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;
 }

 #ifdef	CONFIG_PM_RUNTIME

 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;
 }

 #else

 static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
 		u16 portstatus, u16 portchange)
 {
 	return 0;
 }

 #endif

 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 khubd 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)
 {
 	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 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;

 	if (hcd->phy && !hdev->parent)
 		usb_phy_notify_connect(hcd->phy, udev->speed);

 	/*
 	 * 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;

 	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->phy && !hdev->parent &&
 				!(portstatus & USB_PORT_STAT_CONNECTION))
 			usb_phy_notify_disconnect(hcd->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) */
 		if (hub_is_port_power_switchable(hub)
 				&& !port_is_power_on(hub, portstatus))
 			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);
 			}
 		}

 		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_RUNTIME
 		} 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, reset_device = 0;
 	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
 			reset_device = 1;
 	}

 	/*
 	 * On disconnect USB3 protocol ports transit from U0 to
 	 * SS.Inactive to Rx.Detect. If this happens a warm-
 	 * reset is not needed, but a (re)connect may happen
 	 * before khubd runs and sees the disconnect, and the
 	 * device may be an unknown state.
 	 *
 	 * If the port went through SS.Inactive without khubd
 	 * seeing it the C_LINK_STATE change flag will be set,
 	 * and we reset the dev to put it in a known state.
 	 */
 	if (reset_device || (udev && hub_is_superspeed(hub->hdev)
 				&& (portchange & USB_PORT_STAT_C_LINK_STATE)
 				&& (portstatus & USB_PORT_STAT_CONNECTION))) {
 		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_events(void)
 {
 	struct list_head *tmp;
 	struct usb_device *hdev;
 	struct usb_interface *intf;
 	struct usb_hub *hub;
 	struct device *hub_dev;
 	u16 hubstatus;
 	u16 hubchange;
 	int i, ret;

 	/*
 	 *  We restart the list every time to avoid a deadlock with
 	 * deleting hubs downstream from this one. This should be
 	 * safe since we delete the hub from the event list.
 	 * Not the most efficient, but avoids deadlocks.
 	 */
 	while (1) {

 		/* Grab the first entry at the beginning of the list */
 		spin_lock_irq(&hub_event_lock);
 		if (list_empty(&hub_event_list)) {
 			spin_unlock_irq(&hub_event_lock);
 			break;
 		}

 		tmp = hub_event_list.next;
 		list_del_init(tmp);

 		hub = list_entry(tmp, struct usb_hub, event_list);
 		kref_get(&hub->kref);
 		spin_unlock_irq(&hub_event_lock);

 		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 loop_disconnected;

 		/* If the hub has died, clean up after it */
 		if (hdev->state == USB_STATE_NOTATTACHED) {
 			hub->error = -ENODEV;
 			hub_quiesce(hub, HUB_DISCONNECT);
 			goto loop;
 		}

 		/* Autoresume */
 		ret = usb_autopm_get_interface(intf);
 		if (ret) {
 			dev_dbg(hub_dev, "Can't autoresume: %d\n", ret);
 			goto loop;
 		}

 		/* If this is an inactive hub, do nothing */
 		if (hub->quiescing)
 			goto loop_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 loop_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");
 			}
 		}

  loop_autopm:
 		/* Balance the usb_autopm_get_interface() above */
 		usb_autopm_put_interface_no_suspend(intf);
  loop:
 		/* Balance the usb_autopm_get_interface_no_resume() in
 		 * kick_khubd() and allow autosuspend.
 		 */
 		usb_autopm_put_interface(intf);
  loop_disconnected:
 		usb_unlock_device(hdev);
 		kref_put(&hub->kref, hub_release);

 	} /* end while (1) */
 }

 static int hub_thread(void *__unused)
 {
 	/* khubd 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.
 	 */
 	set_freezable();

 	do {
 		hub_events();
 		wait_event_freezable(khubd_wait,
 				!list_empty(&hub_event_list) ||
 				kthread_should_stop());
 	} while (!kthread_should_stop() || !list_empty(&hub_event_list));

 	pr_debug("%s: khubd exiting\n", usbcore_name);
 	return 0;
 }

 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;
 	}

 	khubd_task = kthread_run(hub_thread, NULL, "khubd");
 	if (!IS_ERR(khubd_task))
 		return 0;

 	/* Fall through if kernel_thread failed */
 	usb_deregister(&hub_driver);
 	printk(KERN_ERR "%s: can't start khubd\n", usbcore_name);

 	return -1;
 }

 void usb_hub_cleanup(void)
 {
 	kthread_stop(khubd_task);

 	/*
 	 * 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 khubd 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 a driver is unbound and it had a pending reset, the reset will
  *   be cancelled.
  *
  * - This function can be called during .probe() or .disconnect()
  *   times. On return from .disconnect(), any pending resets will be
  *   cancelled.
  *
  * There is no no need to lock/unlock the @reset_ws as schedule_work()
  * does its own.
  *
  * NOTE: We don't do any reference count tracking because it is not
  *     needed. The lifecycle of the work_struct is tied to the
  *     usb_interface. Before destroying the interface we cancel the
  *     work_struct, so the fact that work_struct is queued and or
  *     running means the interface (and thus, the device) exist and
  *     are referenced.
  */
 void usb_queue_reset_device(struct usb_interface *iface)
 {
 	schedule_work(&iface->reset_ws);
 }
 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