hub.c 85.1 KB
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/*
 * 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>
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#include <linux/kthread.h>
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#include <linux/mutex.h>
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#include <linux/freezer.h>
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#include <asm/semaphore.h>
#include <asm/uaccess.h>
#include <asm/byteorder.h>

#include "usb.h"
#include "hcd.h"
#include "hub.h"

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struct usb_hub {
	struct device		*intfdev;	/* the "interface" device */
	struct usb_device	*hdev;
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	struct kref		kref;
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	struct urb		*urb;		/* for interrupt polling pipe */

	/* buffer for urb ... with extra space in case of babble */
	char			(*buffer)[8];
	dma_addr_t		buffer_dma;	/* DMA address for buffer */
	union {
		struct usb_hub_status	hub;
		struct usb_port_status	port;
	}			*status;	/* buffer for status reports */
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	struct mutex		status_mutex;	/* for the status buffer */
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	int			error;		/* last reported error */
	int			nerrors;	/* track consecutive errors */

	struct list_head	event_list;	/* hubs w/data or errs ready */
	unsigned long		event_bits[1];	/* status change bitmask */
	unsigned long		change_bits[1];	/* ports with logical connect
							status change */
	unsigned long		busy_bits[1];	/* ports being reset or
							resumed */
#if USB_MAXCHILDREN > 31 /* 8*sizeof(unsigned long) - 1 */
#error event_bits[] is too short!
#endif

	struct usb_hub_descriptor *descriptor;	/* class descriptor */
	struct usb_tt		tt;		/* Transaction Translator */

	unsigned		mA_per_port;	/* current for each child */

	unsigned		limited_power:1;
	unsigned		quiescing:1;
	unsigned		activating:1;
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	unsigned		disconnected:1;
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	unsigned		has_indicators:1;
	u8			indicator[USB_MAXCHILDREN];
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	struct delayed_work	leds;
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};


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/* Protect struct usb_device->state and ->children members
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 * Note: Both are also protected by ->dev.sem, except that ->state can
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 * 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);

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static struct task_struct *khubd_task;
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/* cycle leds on hubs that aren't blinking for attention */
static int blinkenlights = 0;
module_param (blinkenlights, bool, S_IRUGO);
MODULE_PARM_DESC (blinkenlights, "true to cycle leds on hubs");

/*
 * 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 int 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 int 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");


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static inline char *portspeed(int portstatus)
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{
	if (portstatus & (1 << USB_PORT_FEAT_HIGHSPEED))
    		return "480 Mb/s";
	else if (portstatus & (1 << USB_PORT_FEAT_LOWSPEED))
		return "1.5 Mb/s";
	else
		return "12 Mb/s";
}

/* Note that hdev or one of its children must be locked! */
static inline struct usb_hub *hdev_to_hub(struct usb_device *hdev)
{
	return usb_get_intfdata(hdev->actconfig->interface[0]);
}

/* USB 2.0 spec Section 11.24.4.5 */
static int get_hub_descriptor(struct usb_device *hdev, void *data, int size)
{
	int i, ret;

	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,
			USB_DT_HUB << 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
 */
static int 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);
}

/*
 * 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
)
{
	int status = set_port_feature(hub->hdev, (selector << 8) | port1,
			USB_PORT_FEAT_INDICATOR);
	if (status < 0)
		dev_dbg (hub->intfdev,
			"port %d indicator %s status %d\n",
			port1,
			({ char *s; switch (selector) {
			case HUB_LED_AMBER: s = "amber"; break;
			case HUB_LED_GREEN: s = "green"; break;
			case HUB_LED_OFF: s = "off"; break;
			case HUB_LED_AUTO: s = "auto"; break;
			default: s = "??"; break;
			}; s; }),
			status);
}

#define	LED_CYCLE_PERIOD	((2*HZ)/3)

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static void led_work (struct work_struct *work)
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{
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	struct usb_hub		*hub =
		container_of(work, struct usb_hub, leds.work);
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	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 < hub->descriptor->bNbrPorts; 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 %= hub->descriptor->bNbrPorts;
		set_port_led(hub, cursor + 1, HUB_LED_GREEN);
		hub->indicator[cursor] = INDICATOR_CYCLE;
		changed++;
	}
	if (changed)
		schedule_delayed_work(&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; 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; 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 void kick_khubd(struct usb_hub *hub)
{
	unsigned long	flags;

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	/* Suppress autosuspend until khubd runs */
	to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;

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

void usb_kick_khubd(struct usb_device *hdev)
{
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	/* FIXME: What if hdev isn't bound to the hub driver? */
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	kick_khubd(hdev_to_hub(hdev));
}


/* completion function, fires on port status changes and various faults */
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static void hub_irq(struct urb *urb)
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{
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	struct usb_hub *hub = urb->context;
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	int status;
	int i;
	unsigned long bits;

	switch (urb->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", urb->status);
		if ((++hub->nerrors < 10) || hub->error)
			goto resubmit;
		hub->error = urb->status;
		/* FALL THROUGH */
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	/* 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)
{
	return usb_control_msg(hdev, usb_rcvctrlpipe(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.
 */
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static void hub_tt_kevent (struct work_struct *work)
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{
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	struct usb_hub		*hub =
		container_of(work, struct usb_hub, tt.kevent);
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	unsigned long		flags;

	spin_lock_irqsave (&hub->tt.lock, flags);
	while (!list_empty (&hub->tt.clear_list)) {
		struct list_head	*temp;
		struct usb_tt_clear	*clear;
		struct usb_device	*hdev = hub->hdev;
		int			status;

		temp = hub->tt.clear_list.next;
		clear = list_entry (temp, 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);
		spin_lock_irqsave (&hub->tt.lock, flags);

		if (status)
			dev_err (&hdev->dev,
				"clear tt %d (%04x) error %d\n",
				clear->tt, clear->devinfo, status);
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		kfree(clear);
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	}
	spin_unlock_irqrestore (&hub->tt.lock, flags);
}

/**
 * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub
 * @udev: the device whose split transaction failed
 * @pipe: identifies the endpoint of the failed 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.
 */
void usb_hub_tt_clear_buffer (struct usb_device *udev, int 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.
	 */
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	if ((clear = kmalloc (sizeof *clear, GFP_ATOMIC)) == NULL) {
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		dev_err (&udev->dev, "can't save CLEAR_TT_BUFFER state\n");
		/* FIXME recover somehow ... RESET_TT? */
		return;
	}

	/* 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;
	
	/* 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->kevent);
	spin_unlock_irqrestore (&tt->lock, flags);
}

static void hub_power_on(struct usb_hub *hub)
{
	int port1;
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	unsigned pgood_delay = hub->descriptor->bPwrOn2PwrGood * 2;
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	u16 wHubCharacteristics =
			le16_to_cpu(hub->descriptor->wHubCharacteristics);

	/* 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 ((wHubCharacteristics & HUB_CHAR_LPSM) < 2)
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		dev_dbg(hub->intfdev, "enabling power on all ports\n");
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	else
		dev_dbg(hub->intfdev, "trying to enable port power on "
				"non-switchable hub\n");
	for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
		set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
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	/* Wait at least 100 msec for power to become stable */
	msleep(max(pgood_delay, (unsigned) 100));
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}

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static void hub_quiesce(struct usb_hub *hub)
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{
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	/* (nonblocking) khubd and related activity won't re-trigger */
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	hub->quiescing = 1;
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	hub->activating = 0;
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	/* (blocking) stop khubd and related activity */
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	usb_kill_urb(hub->urb);
	if (hub->has_indicators)
		cancel_delayed_work(&hub->leds);
	if (hub->has_indicators || hub->tt.hub)
		flush_scheduled_work();
}

static void hub_activate(struct usb_hub *hub)
{
	int	status;

	hub->quiescing = 0;
	hub->activating = 1;
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	status = usb_submit_urb(hub->urb, GFP_NOIO);
	if (status < 0)
		dev_err(hub->intfdev, "activate --> %d\n", status);
	if (hub->has_indicators && blinkenlights)
		schedule_delayed_work(&hub->leds, LED_CYCLE_PERIOD);

	/* scan all ports ASAP */
	kick_khubd(hub);
}

static int hub_hub_status(struct usb_hub *hub,
		u16 *status, u16 *change)
{
	int ret;

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	mutex_lock(&hub->status_mutex);
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	ret = get_hub_status(hub->hdev, &hub->status->hub);
	if (ret < 0)
		dev_err (hub->intfdev,
			"%s failed (err = %d)\n", __FUNCTION__, ret);
	else {
		*status = le16_to_cpu(hub->status->hub.wHubStatus);
		*change = le16_to_cpu(hub->status->hub.wHubChange); 
		ret = 0;
	}
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	mutex_unlock(&hub->status_mutex);
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	return ret;
}

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static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
{
	struct usb_device *hdev = hub->hdev;
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	int ret = 0;
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	if (hdev->children[port1-1] && set_state)
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		usb_set_device_state(hdev->children[port1-1],
				USB_STATE_NOTATTACHED);
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	if (!hub->error)
		ret = clear_port_feature(hdev, port1, USB_PORT_FEAT_ENABLE);
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	if (ret)
		dev_err(hub->intfdev, "cannot disable port %d (err = %d)\n",
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				port1, ret);
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	return ret;
}

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/*
 * Disable a port and mark a logical connnect-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->intfdev, "logical disconnect on port %d\n", port1);
	hub_port_disable(hub, port1, 1);
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	/* 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);
}

static void disconnect_all_children(struct usb_hub *hub, int logical)
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{
	struct usb_device *hdev = hub->hdev;
	int port1;

	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
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		if (hdev->children[port1-1]) {
			if (logical)
				hub_port_logical_disconnect(hub, port1);
			else
				usb_disconnect(&hdev->children[port1-1]);
		}
	}
}

#ifdef	CONFIG_USB_PERSIST

#define USB_PERSIST	1

/* For "persistent-device" resets we must mark the child devices for reset
 * and turn off a possible connect-change status (so khubd won't disconnect
 * them later).
 */
static void mark_children_for_reset_resume(struct usb_hub *hub)
{
	struct usb_device *hdev = hub->hdev;
	int port1;

	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
		struct usb_device *child = hdev->children[port1-1];

		if (child) {
			child->reset_resume = 1;
			clear_port_feature(hdev, port1,
					USB_PORT_FEAT_C_CONNECTION);
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		}
	}
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}

#else

#define USB_PERSIST	0

static inline void mark_children_for_reset_resume(struct usb_hub *hub)
{ }

#endif	/* CONFIG_USB_PERSIST */

/* caller has locked the hub device */
static void hub_pre_reset(struct usb_interface *intf)
{
	struct usb_hub *hub = usb_get_intfdata(intf);

	/* This routine doesn't run as part of a reset-resume, so it's safe
	 * to disconnect all the drivers below the hub.
	 */
	disconnect_all_children(hub, 0);
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	hub_quiesce(hub);
}

/* caller has locked the hub device */
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static void hub_post_reset(struct usb_interface *intf, int reset_resume)
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{
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	struct usb_hub *hub = usb_get_intfdata(intf);

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	hub_power_on(hub);
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	if (reset_resume) {
		if (USB_PERSIST)
			mark_children_for_reset_resume(hub);
		else {
			/* Reset-resume doesn't call pre_reset, so we have to
			 * disconnect the children here.  But we may not lock
			 * the child devices, so we have to do a "logical"
			 * disconnect.
			 */
			disconnect_all_children(hub, 1);
		}
	}
	hub_activate(hub);
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}


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static int hub_configure(struct usb_hub *hub,
	struct usb_endpoint_descriptor *endpoint)
{
	struct usb_device *hdev = hub->hdev;
	struct device *hub_dev = hub->intfdev;
	u16 hubstatus, hubchange;
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	u16 wHubCharacteristics;
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	unsigned int pipe;
	int maxp, ret;
	char *message;

	hub->buffer = usb_buffer_alloc(hdev, sizeof(*hub->buffer), GFP_KERNEL,
			&hub->buffer_dma);
	if (!hub->buffer) {
		message = "can't allocate hub irq buffer";
		ret = -ENOMEM;
		goto fail;
	}

	hub->status = kmalloc(sizeof(*hub->status), GFP_KERNEL);
	if (!hub->status) {
		message = "can't kmalloc hub status buffer";
		ret = -ENOMEM;
		goto fail;
	}
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	mutex_init(&hub->status_mutex);
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	hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL);
	if (!hub->descriptor) {
		message = "can't kmalloc 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,
			sizeof(*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;
	}

	hdev->maxchild = hub->descriptor->bNbrPorts;
	dev_info (hub_dev, "%d port%s detected\n", hdev->maxchild,
		(hdev->maxchild == 1) ? "" : "s");

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	wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
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	if (wHubCharacteristics & HUB_CHAR_COMPOUND) {
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		int	i;
		char	portstr [USB_MAXCHILDREN + 1];

		for (i = 0; i < hdev->maxchild; i++)
			portstr[i] = hub->descriptor->DeviceRemovable
				    [((i + 1) / 8)] & (1 << ((i + 1) % 8))
				? 'F' : 'R';
		portstr[hdev->maxchild] = 0;
		dev_dbg(hub_dev, "compound device; port removable status: %s\n", portstr);
	} else
		dev_dbg(hub_dev, "standalone hub\n");

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	switch (wHubCharacteristics & HUB_CHAR_LPSM) {
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		case 0x00:
			dev_dbg(hub_dev, "ganged power switching\n");
			break;
		case 0x01:
			dev_dbg(hub_dev, "individual port power switching\n");
			break;
		case 0x02:
		case 0x03:
			dev_dbg(hub_dev, "no power switching (usb 1.0)\n");
			break;
	}

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	switch (wHubCharacteristics & HUB_CHAR_OCPM) {
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		case 0x00:
			dev_dbg(hub_dev, "global over-current protection\n");
			break;
		case 0x08:
			dev_dbg(hub_dev, "individual port over-current protection\n");
			break;
		case 0x10:
		case 0x18:
			dev_dbg(hub_dev, "no over-current protection\n");
                        break;
	}

	spin_lock_init (&hub->tt.lock);
	INIT_LIST_HEAD (&hub->tt.clear_list);
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	INIT_WORK (&hub->tt.kevent, hub_tt_kevent);
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	switch (hdev->descriptor.bDeviceProtocol) {
		case 0:
			break;
		case 1:
			dev_dbg(hub_dev, "Single TT\n");
			hub->tt.hub = hdev;
			break;
		case 2:
			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;
		default:
			dev_dbg(hub_dev, "Unrecognized hub protocol %d\n",
				hdev->descriptor.bDeviceProtocol);
			break;
	}

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	/* Note 8 FS bit times == (8 bits / 12000000 bps) ~= 666ns */
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	switch (wHubCharacteristics & HUB_CHAR_TTTT) {
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		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);
			}
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			break;
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		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);
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			break;
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		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);
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			break;
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		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);
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			break;
	}

	/* probe() zeroes hub->indicator[] */
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	if (wHubCharacteristics & HUB_CHAR_PORTIND) {
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		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);
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	if (ret < 2) {
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		message = "can't get hub status";
		goto fail;
	}
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	le16_to_cpus(&hubstatus);
	if (hdev == hdev->bus->root_hub) {
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		if (hdev->bus_mA == 0 || hdev->bus_mA >= 500)
			hub->mA_per_port = 500;
		else {
			hub->mA_per_port = hdev->bus_mA;
			hub->limited_power = 1;
		}
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	} else if ((hubstatus & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
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		dev_dbg(hub_dev, "hub controller current requirement: %dmA\n",
			hub->descriptor->bHubContrCurrent);
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		hub->limited_power = 1;
		if (hdev->maxchild > 0) {
			int remaining = hdev->bus_mA -
					hub->descriptor->bHubContrCurrent;

			if (remaining < hdev->maxchild * 100)
				dev_warn(hub_dev,
					"insufficient power available "
					"to use all downstream ports\n");
			hub->mA_per_port = 100;		/* 7.2.1.1 */
		}
	} else {	/* Self-powered external hub */
		/* FIXME: What about battery-powered external hubs that
		 * provide less current per port? */
		hub->mA_per_port = 500;
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	}
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	if (hub->mA_per_port < 500)
		dev_dbg(hub_dev, "%umA bus power budget for each child\n",
				hub->mA_per_port);
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	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");

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	if ((wHubCharacteristics & HUB_CHAR_OCPM) == 0)
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		dev_dbg(hub_dev, "%sover-current condition exists\n",
			(hubstatus & HUB_STATUS_OVERCURRENT) ? "" : "no ");

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	/* 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. */
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	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) {
		message = "couldn't allocate interrupt urb";
		ret = -ENOMEM;
		goto fail;
	}

	usb_fill_int_urb(hub->urb, hdev, pipe, *hub->buffer, maxp, hub_irq,
		hub, endpoint->bInterval);
	hub->urb->transfer_dma = hub->buffer_dma;
	hub->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	/* maybe cycle the hub leds */
	if (hub->has_indicators && blinkenlights)
		hub->indicator [0] = INDICATOR_CYCLE;

	hub_power_on(hub);
	hub_activate(hub);
	return 0;

fail:
	dev_err (hub_dev, "config failed, %s (err %d)\n",
			message, ret);
	/* hub_disconnect() frees urb and descriptor */
	return ret;
}

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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);
}

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static unsigned highspeed_hubs;

static void hub_disconnect(struct usb_interface *intf)
{
	struct usb_hub *hub = usb_get_intfdata (intf);
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	/* Take the hub off the event list and don't let it be added again */
	spin_lock_irq(&hub_event_lock);
	list_del_init(&hub->event_list);
	hub->disconnected = 1;
	spin_unlock_irq(&hub_event_lock);
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	/* Disconnect all children and quiesce the hub */
	hub->error = 0;
	hub_pre_reset(intf);

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	usb_set_intfdata (intf, NULL);
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	if (hub->hdev->speed == USB_SPEED_HIGH)
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		highspeed_hubs--;

	usb_free_urb(hub->urb);
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	kfree(hub->descriptor);
	kfree(hub->status);
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	usb_buffer_free(hub->hdev, sizeof(*hub->buffer), hub->buffer,
			hub->buffer_dma);
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	kref_put(&hub->kref, hub_release);
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}

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);

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#ifdef	CONFIG_USB_OTG_BLACKLIST_HUB
	if (hdev->parent) {
		dev_warn(&intf->dev, "ignoring external hub\n");
		return -ENODEV;
	}
#endif

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	/* 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;

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	/* If it's not an interrupt in endpoint, we'd better punt! */
	if (!usb_endpoint_is_int_in(endpoint))
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		goto descriptor_error;

	/* We found a hub */
	dev_info (&intf->dev, "USB hub found\n");

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	hub = kzalloc(sizeof(*hub), GFP_KERNEL);
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	if (!hub) {
		dev_dbg (&intf->dev, "couldn't kmalloc hub struct\n");
		return -ENOMEM;
	}

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	kref_init(&hub->kref);
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	INIT_LIST_HEAD(&hub->event_list);
	hub->intfdev = &intf->dev;
	hub->hdev = hdev;
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	INIT_DELAYED_WORK(&hub->leds, led_work);
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	usb_get_intf(intf);
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	usb_set_intfdata (intf, hub);
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	intf->needs_remote_wakeup = 1;
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	if (hdev->speed == USB_SPEED_HIGH)
		highspeed_hubs++;

	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);

	/* 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 (hdev->children[i] == NULL)
					info->port[i] = 0;
				else
					info->port[i] =
						hdev->children[i]->devnum;
			}
		}
		spin_unlock_irq(&device_state_lock);

		return info->nports + 1;
		}

	default:
		return -ENOSYS;
	}
}


static void recursively_mark_NOTATTACHED(struct usb_device *udev)
{
	int i;

	for (i = 0; i < udev->maxchild; ++i) {
		if (udev->children[i])
			recursively_mark_NOTATTACHED(udev->children[i]);
	}
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	if (udev->state == USB_STATE_SUSPENDED)
		udev->discon_suspended = 1;
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	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;

	spin_lock_irqsave(&device_state_lock, flags);
	if (udev->state == USB_STATE_NOTATTACHED)
		;	/* do nothing */
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	else if (new_state != USB_STATE_NOTATTACHED) {
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		/* root hub wakeup capabilities are managed out-of-band
		 * and may involve silicon errata ... ignore them here.
		 */
		if (udev->parent) {
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			if (udev->state == USB_STATE_SUSPENDED
					|| new_state == USB_STATE_SUSPENDED)
				;	/* No change to wakeup settings */
			else if (new_state == USB_STATE_CONFIGURED)
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				device_init_wakeup(&udev->dev,
					(udev->actconfig->desc.bmAttributes
					 & USB_CONFIG_ATT_WAKEUP));
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			else
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				device_init_wakeup(&udev->dev, 0);
		}
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		udev->state = new_state;
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	} else
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		recursively_mark_NOTATTACHED(udev);
	spin_unlock_irqrestore(&device_state_lock, flags);
}


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#ifdef	CONFIG_PM
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/**
 * usb_reset_suspended_device - reset a suspended device instead of resuming it
 * @udev: device to be reset instead of resumed
 *
 * 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.
 *
 * As an alternative, this routine attempts to recover power sessions for
 * devices that are still present by resetting them instead of resuming
 * them.  If all goes well, the devices will appear to persist across the
 * the interruption of the power sessions.
 *
 * This facility is inherently dangerous.  Although usb_reset_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.
 */
int usb_reset_suspended_device(struct usb_device *udev)
{
	int rc = 0;

	dev_dbg(&udev->dev, "usb %sresume\n", "reset-");

	/* After we're done the device won't be suspended any more.
	 * In addition, the reset won't work if udev->state is SUSPENDED.
	 */
	usb_set_device_state(udev, udev->actconfig
			? USB_STATE_CONFIGURED
			: USB_STATE_ADDRESS);

	/* Root hubs don't need to be (and can't be) reset */
	if (udev->parent)
		rc = usb_reset_device(udev);
	return rc;
}

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/**
 * 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
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 * has been reset.  The routine marks @rhdev as having lost power.  When
 * the hub driver is resumed it will take notice; if CONFIG_USB_PERSIST
 * is enabled then it will carry out power-session recovery, otherwise
 * it will disconnect all the child devices.
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 */
void usb_root_hub_lost_power(struct usb_device *rhdev)
{
	dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
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	rhdev->reset_resume = 1;
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}
EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);

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#endif	/* CONFIG_PM */
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static void choose_address(struct usb_device *udev)
{
	int		devnum;
	struct usb_bus	*bus = udev->bus;

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

	/* 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_address(struct usb_device *udev)
{
	if (udev->devnum > 0) {
		clear_bit(udev->devnum, udev->bus->devmap.devicemap);
		udev->devnum = -1;
	}
}

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#ifdef	CONFIG_USB_SUSPEND

static void usb_stop_pm(struct usb_device *udev)
{
	/* Synchronize with the ksuspend thread to prevent any more
	 * autosuspend requests from being submitted, and decrement
	 * the parent's count of unsuspended children.
	 */
	usb_pm_lock(udev);
	if (udev->parent && !udev->discon_suspended)
		usb_autosuspend_device(udev->parent);
	usb_pm_unlock(udev);

	/* Stop any autosuspend requests already submitted */
	cancel_rearming_delayed_work(&udev->autosuspend);
}

#else

static inline void usb_stop_pm(struct usb_device *udev)
{ }

#endif

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/**
 * 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 this routine will acquire the
 * usb_bus_list_lock on behalf of the caller.
 *
 * 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_device	*udev = *pdev;
	int			i;

	if (!udev) {
		pr_debug ("%s nodev\n", __FUNCTION__);
		return;
	}

	/* mark the device as inactive, so any further urb submissions for
	 * this device (and any of its children) will fail immediately.
	 * this quiesces everyting except pending urbs.
	 */
	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
	dev_info (&udev->dev, "USB disconnect, address %d\n", udev->devnum);

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	usb_lock_device(udev);

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	/* Free up all the children before we remove this device */
	for (i = 0; i < USB_MAXCHILDREN; i++) {
		if (udev->children[i])
			usb_disconnect(&udev->children[i]);
	}

	/* 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.
	 */
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	dev_dbg (&udev->dev, "unregistering device\n");
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	usb_disable_device(udev, 0);

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	usb_unlock_device(udev);

	/* Unregister the device.  The device driver is responsible
	 * for removing the device files from usbfs and sysfs and for
	 * de-configuring the device.
	 */
	device_del(&udev->dev);
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	/* Free the device number and delete the parent's children[]
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	 * (or root_hub) pointer.
	 */
	release_address(udev);

	/* Avoid races with recursively_mark_NOTATTACHED() */
	spin_lock_irq(&device_state_lock);
	*pdev = NULL;
	spin_unlock_irq(&device_state_lock);

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	usb_stop_pm(udev);
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	put_device(&udev->dev);
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}

#ifdef DEBUG
static void show_string(struct usb_device *udev, char *id, char *string)
{
	if (!string)
		return;
	dev_printk(KERN_INFO, &udev->dev, "%s: %s\n", id, string);
}

#else
static inline void show_string(struct usb_device *udev, char *id, char *string)
{}
#endif


#ifdef	CONFIG_USB_OTG
#include "otg_whitelist.h"
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static int __usb_port_suspend(struct usb_device *, int port1);
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#endif

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/**
 * usb_new_device - perform initial device setup (usbcore-internal)
 * @udev: newly addressed device (in ADDRESS state)
 *
 * This is called with devices which have been enumerated, but not yet
 * configured.  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.
 *
 * It will return if the device is configured properly or not.  Zero if
 * the interface was registered with the driver core; else a negative
 * errno value.
 *
 * 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.
 */
int usb_new_device(struct usb_device *udev)
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{
	int err;

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	/* Determine quirks */
	usb_detect_quirks(udev);

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	err = usb_get_configuration(udev);
	if (err < 0) {
		dev_err(&udev->dev, "can't read configurations, error %d\n",
			err);
		goto fail;
	}

	/* read the standard strings and cache them if present */
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	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);
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	/* Tell the world! */
	dev_dbg(&udev->dev, "new 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);

#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 = 0;
		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) {
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				unsigned		port1 = udev->portnum;
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				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) {
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			err = __usb_port_suspend(udev, udev->bus->otg_port);
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			if (err < 0)
				dev_dbg(&udev->dev, "HNP fail, %d\n", err);
		}
		err = -ENODEV;
		goto fail;
	}
#endif

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	/* export the usbdev device-node for libusb */
	udev->dev.devt = MKDEV(USB_DEVICE_MAJOR,
			(((udev->bus->busnum-1) * 128) + (udev->devnum-1)));

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	/* Register the device.  The device driver is responsible
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	 * for adding the device files to sysfs and for configuring
	 * the device.
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	 */
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	err = device_add(&udev->dev);
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	if (err) {
		dev_err(&udev->dev, "can't device_add, error %d\n", err);
		goto fail;
	}
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	/* Increment the parent's count of unsuspended children */
	if (udev->parent)
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		usb_autoresume_device(udev->parent);
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exit:
	return err;
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fail:
	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
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	goto exit;
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}

static int hub_port_status(struct usb_hub *hub, int port1,
			       u16 *status, u16 *change)
{
	int ret;

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	mutex_lock(&hub->status_mutex);
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	ret = get_port_status(hub->hdev, port1, &hub->status->port);
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	if (ret < 4) {
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		dev_err (hub->intfdev,
			"%s failed (err = %d)\n", __FUNCTION__, ret);
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		if (ret >= 0)
			ret = -EIO;
	} else {
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		*status = le16_to_cpu(hub->status->port.wPortStatus);
		*change = le16_to_cpu(hub->status->port.wPortChange); 
		ret = 0;
	}
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	mutex_unlock(&hub->status_mutex);
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	return ret;
}

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/* 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;
}


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#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 == old_scheme_first)

#define HUB_ROOT_RESET_TIME	50	/* times are in msec */
#define HUB_SHORT_RESET_TIME	10
#define HUB_LONG_RESET_TIME	200
#define HUB_RESET_TIMEOUT	500

static int hub_port_wait_reset(struct usb_hub *hub, int port1,
				struct usb_device *udev, unsigned int delay)
{
	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;

		/* Device went away? */
		if (!(portstatus & USB_PORT_STAT_CONNECTION))
			return -ENOTCONN;

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		/* bomb out completely if the connection bounced */
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		if ((portchange & USB_PORT_STAT_C_CONNECTION))
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			return -ENOTCONN;
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		/* if we`ve finished resetting, then break out of the loop */
		if (!(portstatus & USB_PORT_STAT_RESET) &&
		    (portstatus & USB_PORT_STAT_ENABLE)) {
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			if (hub_is_wusb(hub))
				udev->speed = USB_SPEED_VARIABLE;
			else if (portstatus & USB_PORT_STAT_HIGH_SPEED)
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				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;
		}

		/* switch to the long delay after two short delay failures */
		if (delay_time >= 2 * HUB_SHORT_RESET_TIME)
			delay = HUB_LONG_RESET_TIME;

		dev_dbg (hub->intfdev,
			"port %d not reset yet, waiting %dms\n",
			port1, delay);
	}

	return -EBUSY;
}

static int hub_port_reset(struct usb_hub *hub, int port1,
				struct usb_device *udev, unsigned int delay)
{
	int i, status;

	/* Reset the port */
	for (i = 0; i < PORT_RESET_TRIES; i++) {
		status = set_port_feature(hub->hdev,
				port1, USB_PORT_FEAT_RESET);
		if (status)
			dev_err(hub->intfdev,
					"cannot reset port %d (err = %d)\n",
					port1, status);
		else {
			status = hub_port_wait_reset(hub, port1, udev, delay);
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			if (status && status != -ENOTCONN)
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				dev_dbg(hub->intfdev,
						"port_wait_reset: err = %d\n",
						status);
		}

		/* return on disconnect or reset */
		switch (status) {
		case 0:
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			/* TRSTRCY = 10 ms; plus some extra */
			msleep(10 + 40);
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			/* FALL THROUGH */
		case -ENOTCONN:
		case -ENODEV:
			clear_port_feature(hub->hdev,
				port1, USB_PORT_FEAT_C_RESET);
			/* FIXME need disconnect() for NOTATTACHED device */
			usb_set_device_state(udev, status
					? USB_STATE_NOTATTACHED
					: USB_STATE_DEFAULT);
			return status;
		}

		dev_dbg (hub->intfdev,
			"port %d not enabled, trying reset again...\n",
			port1);
		delay = HUB_LONG_RESET_TIME;
	}

	dev_err (hub->intfdev,
		"Cannot enable port %i.  Maybe the USB cable is bad?\n",
		port1);

	return status;
}

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#ifdef	CONFIG_PM
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#ifdef	CONFIG_USB_SUSPEND

/*
 * 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.
 */
static int hub_port_suspend(struct usb_hub *hub, int port1,
		struct usb_device *udev)
{
	int	status;

	// dev_dbg(hub->intfdev, "suspend port %d\n", port1);

	/* 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.
	 */
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	if (udev->do_remote_wakeup) {
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		status = 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);
		if (status)
			dev_dbg(&udev->dev,
				"won't remote wakeup, status %d\n",
				status);
	}

	/* see 7.1.7.6 */
	status = set_port_feature(hub->hdev, port1, USB_PORT_FEAT_SUSPEND);
	if (status) {
		dev_dbg(hub->intfdev,
			"can't suspend port %d, status %d\n",
			port1, status);
		/* paranoia:  "should not happen" */
		(void) 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 {
		/* device has up to 10 msec to fully suspend */
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		dev_dbg(&udev->dev, "usb %ssuspend\n",
				udev->auto_pm ? "auto-" : "");
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		usb_set_device_state(udev, USB_STATE_SUSPENDED);
		msleep(10);
	}
	return status;
}

/*
 * Devices on USB hub ports have only one "suspend" state, corresponding
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 * to ACPI D2, "may cause the device to lose some context".
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 * 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.
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 *
 * If CONFIG_USB_SUSPEND isn't enabled, devices only really suspend when
 * the root hub for their bus goes into global suspend ... so we don't
 * (falsely) update the device power state to say it suspended.
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 */
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static int __usb_port_suspend (struct usb_device *udev, int port1)
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{
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	int	status = 0;
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	/* caller owns the udev device lock */
	if (port1 < 0)
		return port1;

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	/* we change the device's upstream USB link,
	 * but root hubs have no upstream USB link.
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	 */
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	if (udev->parent)
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		status = hub_port_suspend(hdev_to_hub(udev->parent), port1,
				udev);
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	else {
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		dev_dbg(&udev->dev, "usb %ssuspend\n",
				udev->auto_pm ? "auto-" : "");
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		usb_set_device_state(udev, USB_STATE_SUSPENDED);
	}
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	return status;
}

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/*
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 * usb_port_suspend - suspend a usb device's upstream port
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 * @udev: device that's no longer in active use
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 * Context: must be able to sleep; device not locked; pm locks held
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 *
 * 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
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 * suspend by the host, using usb_port_resume().  It's also routine
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 * to disconnect devices while they are suspended.
 *
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 * This only affects the USB hardware for a device; its interfaces
 * (and, for hubs, child devices) must already have been suspended.
 *
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 * 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.
 *
 * Returns 0 on success, else negative errno.
 */
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int usb_port_suspend(struct usb_device *udev)
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{
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	return __usb_port_suspend(udev, udev->portnum);
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}
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/*
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 * 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.  These routines kick in shortly after
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 * 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.
 */
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static int finish_port_resume(struct usb_device *udev)
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{
	int	status;
	u16	devstatus;

	/* caller owns the udev device lock */
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	dev_dbg(&udev->dev, "finish resume\n");
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	/* 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 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.
	 */
	status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
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	if (status >= 0)
		status = (status == 2 ? 0 : -ENODEV);

	if (status)
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		dev_dbg(&udev->dev,
			"gone after usb resume? status %d\n",
			status);
	else if (udev->actconfig) {
		le16_to_cpus(&devstatus);
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		if ((devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
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				&& udev->parent) {
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			status = 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);
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			if (status)
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				dev_dbg(&udev->dev, "disable remote "
					"wakeup, status %d\n", status);
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		}
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		status = 0;

	} else if (udev->devnum <= 0) {
		dev_dbg(&udev->dev, "bogus resume!\n");
		status = -EINVAL;
	}
	return status;
}

static int
hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
{
	int	status;