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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 <linuxcomp.h>

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/ioctl.h>
#ifdef CONFIG_USB_DEBUG
        #define DEBUG
#else
        #undef DEBUG
#endif
#include <linux/usb.h>
#include <linux/usbdevice_fs.h>
#include <linux/suspend.h>

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

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

/* Wakes up khubd */
static spinlock_t hub_event_lock = SPIN_LOCK_UNLOCKED;
static DECLARE_MUTEX(usb_address0_sem);

static LIST_HEAD(hub_event_list);       /* List of hubs needing servicing */
static LIST_HEAD(hub_list);             /* List of all hubs (for cleanup) */

static DECLARE_WAIT_QUEUE_HEAD(khubd_wait);
static pid_t khubd_pid = 0;                     /* PID of khubd */
static DECLARE_COMPLETION(khubd_exited);

//#ifdef        DEBUG
static inline char *portspeed (int portstatus)
{
        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";
}
//#endif

/* for dev_info, dev_dbg, etc */
static inline struct device *hubdev (struct usb_device *dev)
{
        return &dev->actconfig->interface[0]->dev;
}

/* USB 2.0 spec Section 11.24.4.5 */
static int get_hub_descriptor(struct usb_device *dev, void *data, int size)
{
        return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
                USB_DT_HUB << 8, 0, data, size, HZ * USB_CTRL_GET_TIMEOUT);
}

/*
 * USB 2.0 spec Section 11.24.2.1
 */

static int clear_hub_feature(struct usb_device *dev, int feature)
{
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                USB_REQ_CLEAR_FEATURE, USB_RT_HUB, feature, 0, NULL, 0, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.2
 * BUG: doesn't handle port indicator selector in high byte of wIndex
 */

static int clear_port_feature(struct usb_device *dev, int port, int feature)
{
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature, port, NULL, 0, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.13
 * BUG: doesn't handle port indicator selector in high byte of wIndex
 */

static int set_port_feature(struct usb_device *dev, int port, int feature)
{
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                USB_REQ_SET_FEATURE, USB_RT_PORT, feature, port, NULL, 0, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.6
 */

static int get_hub_status(struct usb_device *dev,
                struct usb_hub_status *data)
{
        return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
                data, sizeof(*data), HZ * USB_CTRL_GET_TIMEOUT);
}

/*
 * USB 2.0 spec Section 11.24.2.7
 */

static int get_port_status(struct usb_device *dev, int port,
                struct usb_port_status *data)
{
        return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port,
                data, sizeof(*data), HZ * USB_CTRL_GET_TIMEOUT);
}

/* completion function, fires on port status changes and various faults */
static void hub_irq(struct urb *urb, struct pt_regs *regs)
{
        struct usb_hub *hub = (struct usb_hub *)urb->context;
//**    unsigned long flags; 2.6.1
        int status;

        spin_lock(&hub_event_lock);
        hub->urb_active = 0;
        if (hub->urb_complete) {        /* disconnect or rmmod */
                complete(hub->urb_complete);
                goto done;
        }

        switch (urb->status) {
        case -ENOENT:           /* synchronous unlink */
        case -ECONNRESET:       /* async unlink */
        case -ESHUTDOWN:        /* hardware going away */
                goto done;
//**            return; 2.6.1
 
        default:                /* presumably an error */
                /* Cause a hub reset after 10 consecutive errors */
                dev_dbg (&hub->intf->dev, "transfer --> %d\n", urb->status);
                if ((++hub->nerrors < 10) || hub->error)
                        goto resubmit;
                hub->error = urb->status;
                /* FALL THROUGH */
       
        /* let khubd handle things */
        case 0:                 /* we got data:  port status changed */
                break;
        }

        hub->nerrors = 0;

        /* Something happened, let khubd figure it out */
//**    spin_lock_irqsave(&hub_event_lock, flags); 2.6.1
        if (list_empty(&hub->event_list)) {
                list_add(&hub->event_list, &hub_event_list);
                wake_up(&khubd_wait);
        }
//**    spin_unlock_irqrestore(&hub_event_lock, flags); 2.6.1

resubmit:
        if ((status = usb_submit_urb (hub->urb, GFP_ATOMIC)) != 0
                        /* ENODEV means we raced disconnect() */
                        && status != -ENODEV)
                dev_err (&hub->intf->dev, "resubmit --> %d\n", urb->status);
               
        if (status == 0)
                hub->urb_active = 1;
done:
        spin_unlock(&hub_event_lock);
}

/* USB 2.0 spec Section 11.24.2.3 */
static inline int
hub_clear_tt_buffer (struct usb_device *hub, u16 devinfo, u16 tt)
{
        return usb_control_msg (hub, usb_rcvctrlpipe (hub, 0),
                HUB_CLEAR_TT_BUFFER, USB_DIR_IN | USB_RECIP_OTHER,
                devinfo, tt, 0, 0, HZ);
}

/*
 * 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_kevent (void *arg)
{
        struct usb_hub          *hub = arg;
        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       *dev;
                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);
                dev = interface_to_usbdev (hub->intf);
                status = hub_clear_tt_buffer (dev, clear->devinfo, clear->tt);
                spin_lock_irqsave (&hub->tt.lock, flags);

                if (status)
                        err ("usb-%s-%s clear tt %d (%04x) error %d",
                                dev->bus->bus_name, dev->devpath,
                                clear->tt, clear->devinfo, status);
                kfree (clear);
        }
        spin_unlock_irqrestore (&hub->tt.lock, flags);
}

/**
 * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub
 * @dev: 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 *dev, int pipe)
{
        struct usb_tt           *tt = dev->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, SLAB_ATOMIC)) == 0) {
                err ("can't save CLEAR_TT_BUFFER state for hub at usb-%s-%s",
                        dev->bus->bus_name, tt->hub->devpath);
                /* FIXME recover somehow ... RESET_TT? */
                return;
        }

        /* info that CLEAR_TT_BUFFER needs */
        clear->tt = tt->multi ? dev->ttport : 1;
        clear->devinfo = usb_pipeendpoint (pipe);
        clear->devinfo |= dev->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)
{
        struct usb_device *dev;
        int i;

        /* Enable power to the ports */
        dev_dbg(hubdev(interface_to_usbdev(hub->intf)),
                "enabling power on all ports\n");
        dev = interface_to_usbdev(hub->intf);
        for (i = 0; i < hub->descriptor->bNbrPorts; i++)
                set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);

        /* Wait for power to be enabled */
        wait_ms(hub->descriptor->bPwrOn2PwrGood * 2);
}

static int hub_hub_status(struct usb_hub *hub,
                u16 *status, u16 *change)
{
        struct usb_device *dev = interface_to_usbdev (hub->intf);
        int ret;

        ret = get_hub_status(dev, &hub->status->hub);
        if (ret < 0)
                dev_err (hubdev (dev),
                        "%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;
        }
        return ret;
}

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

        hub->buffer = usb_buffer_alloc(dev, 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;
        }

        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(dev, 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;
        }

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

        le16_to_cpus(&hub->descriptor->wHubCharacteristics);

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

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

        switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_LPSM) {
                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, "unknown reserved power switching mode\n");
                        break;
        }

        switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_OCPM) {
                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);
        INIT_WORK (&hub->tt.kevent, hub_tt_kevent, hub);
        switch (dev->descriptor.bDeviceProtocol) {
                case 0:
                        break;
                case 1:
                        dev_dbg(hub_dev, "Single TT\n");
                        hub->tt.hub = dev;
                        break;
                case 2:
                        dev_dbg(hub_dev, "TT per port\n");
                        hub->tt.hub = dev;
                        hub->tt.multi = 1;
                        break;
                default:
                        dev_dbg(hub_dev, "Unrecognized hub protocol %d\n",
                                dev->descriptor.bDeviceProtocol);
                        break;
        }

        switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_TTTT) {
                case 0x00:
                        if (dev->descriptor.bDeviceProtocol != 0)
                                dev_dbg(hub_dev, "TT requires at most 8 FS bit times\n");
                        break;
                case 0x20:
                        dev_dbg(hub_dev, "TT requires at most 16 FS bit times\n");
                        break;
                case 0x40:
                        dev_dbg(hub_dev, "TT requires at most 24 FS bit times\n");
                        break;
                case 0x60:
                        dev_dbg(hub_dev, "TT requires at most 32 FS bit times\n");
                        break;
        }

        dev_dbg(hub_dev, "Port indicators are %s supported\n",
            (hub->descriptor->wHubCharacteristics & HUB_CHAR_PORTIND)
                ? "" : "not");

        dev_dbg(hub_dev, "power on to power good time: %dms\n",
                hub->descriptor->bPwrOn2PwrGood * 2);
        dev_dbg(hub_dev, "hub controller current requirement: %dmA\n",
                hub->descriptor->bHubContrCurrent);

        ret = hub_hub_status(hub, &hubstatus, &hubchange);
        if (ret < 0) {
                message = "can't get hub status";
                goto fail;
        }

        dev_dbg(hub_dev, "local power source is %s\n",
                (hubstatus & HUB_STATUS_LOCAL_POWER)
                ? "lost (inactive)" : "good");

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

        /* Start the interrupt endpoint */
        pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
        maxp = usb_maxpacket(dev, 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, dev, 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;
        ret = usb_submit_urb(hub->urb, GFP_KERNEL);
        if (ret) {
                message = "couldn't submit status urb";
                goto fail;
        }
        hub->urb_active = 1;
               
        /* Wake up khubd */
        wake_up(&khubd_wait);

        hub_power_on(hub);

        return 0;

fail:
        dev_err (&hub->intf->dev, "config failed, %s (err %d)\n",
                        message, ret);
        /* hub_disconnect() frees urb and descriptor */
        return ret;
}

static void hub_disconnect(struct usb_interface *intf)
{
        struct usb_hub *hub = usb_get_intfdata (intf);
        DECLARE_COMPLETION(urb_complete);
        unsigned long flags;

        if (!hub)
                return;

        usb_set_intfdata (intf, NULL);
        spin_lock_irqsave(&hub_event_lock, flags);
        hub->urb_complete = &urb_complete;

        /* Delete it and then reset it */
        list_del_init(&hub->event_list);
        list_del_init(&hub->hub_list);

        spin_unlock_irqrestore(&hub_event_lock, flags);

        down(&hub->khubd_sem); /* Wait for khubd to leave this hub alone. */
        up(&hub->khubd_sem);

        /* assuming we used keventd, it must quiesce too */
        if (hub->tt.hub)
                flush_scheduled_work ();

        if (hub->urb) {
                usb_unlink_urb(hub->urb);
                if (hub->urb_active)
                        wait_for_completion(&urb_complete);
                usb_free_urb(hub->urb);
                hub->urb = NULL;
        }

        if (hub->descriptor) {
                kfree(hub->descriptor);
                hub->descriptor = NULL;
        }

        if (hub->status) {
                kfree(hub->status);
                hub->status = NULL;
        }

        if (hub->buffer) {
                usb_buffer_free(interface_to_usbdev(intf),
                                sizeof(*hub->buffer), hub->buffer,
                                hub->buffer_dma);
                hub->buffer = NULL;
        }

        /* Free the memory */
        kfree(hub);
}

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 *dev;
        struct usb_hub *hub;
        unsigned long flags;

        desc = intf->altsetting + intf->act_altsetting;
        dev = interface_to_usbdev(intf);

        /* 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;

        /* Output endpoint? Curiouser and curiouser.. */
        if (!(endpoint->bEndpointAddress & USB_DIR_IN)) {
                goto descriptor_error;
        }

        /* If it's not an interrupt endpoint, we'd better punt! */
        if ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
                        != USB_ENDPOINT_XFER_INT) {
                goto descriptor_error;
                return -EIO;
        }

        /* We found a hub */
        dev_info (hubdev (dev), "USB hub found\n");

        hub = kmalloc(sizeof(*hub), GFP_KERNEL);
        if (!hub) {
                err("couldn't kmalloc hub struct");
                return -ENOMEM;
        }

        memset(hub, 0, sizeof(*hub));

        INIT_LIST_HEAD(&hub->event_list);
        hub->intf = intf;
        init_MUTEX(&hub->khubd_sem);

        /* Record the new hub's existence */
        spin_lock_irqsave(&hub_event_lock, flags);
        INIT_LIST_HEAD(&hub->hub_list);
        list_add(&hub->hub_list, &hub_list);
        spin_unlock_irqrestore(&hub_event_lock, flags);

        usb_set_intfdata (intf, hub);

        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 *hub = interface_to_usbdev (intf);

        /* assert ifno == 0 (part of hub spec) */
        switch (code) {
        case USBDEVFS_HUB_PORTINFO: {
                struct usbdevfs_hub_portinfo *info = user_data;
                unsigned long flags;
                int i;

                spin_lock_irqsave(&hub_event_lock, flags);
                if (hub->devnum <= 0)
                        info->nports = 0;
                else {
                        info->nports = hub->maxchild;
                        for (i = 0; i < info->nports; i++) {
                                if (hub->children[i] == NULL)
                                        info->port[i] = 0;
                                else
                                        info->port[i] =
                                                hub->children[i]->devnum;
                        }
                }
                spin_unlock_irqrestore(&hub_event_lock, flags);

                return info->nports + 1;
                }

        default:
                return -ENOSYS;
        }
}

static int hub_reset(struct usb_hub *hub)
{
        struct usb_device *dev = interface_to_usbdev(hub->intf);
        int i;

        /* Disconnect any attached devices */
        for (i = 0; i < hub->descriptor->bNbrPorts; i++) {
                if (dev->children[i])
                        usb_disconnect(&dev->children[i]);
        }

        /* Attempt to reset the hub */
        if (hub->urb)
                usb_unlink_urb(hub->urb);
        else
                return -1;

        if (usb_reset_device(dev))
                return -1;

        hub->urb->dev = dev;                                                    
        if (usb_submit_urb(hub->urb, GFP_KERNEL))
                return -1;

        hub_power_on(hub);

        return 0;
}

static void hub_start_disconnect(struct usb_device *dev)
{
        struct usb_device *parent = dev->parent;
        int i;

        /* Find the device pointer to disconnect */
        if (parent) {
                for (i = 0; i < parent->maxchild; i++) {
                        if (parent->children[i] == dev) {
                                usb_disconnect(&parent->children[i]);
                                return;
                        }
                }
        }

        err("cannot disconnect hub %s", dev->devpath);
}

static int hub_port_status(struct usb_device *dev, int port,
                               u16 *status, u16 *change)
{
        struct usb_hub *hub = usb_get_intfdata(dev->actconfig->interface[0]);
        int ret;

        if (!hub)
                return -ENODEV;

        ret = get_port_status(dev, port + 1, &hub->status->port);
        if (ret < 0)
                dev_err (hubdev (dev),
                        "%s failed (err = %d)\n", __FUNCTION__, ret);
        else {
                *status = le16_to_cpu(hub->status->port.wPortStatus);
                *change = le16_to_cpu(hub->status->port.wPortChange);
                ret = 0;
        }
        return ret;
}

#define HUB_RESET_TRIES         5
#define HUB_PROBE_TRIES         2
#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

/* return: -1 on error, 0 on success, 1 on disconnect.  */
static int hub_port_wait_reset(struct usb_device *hub, int port,
                                struct usb_device *dev, 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 */
                wait_ms(delay);
               
                /* read and decode port status */
                ret = hub_port_status(hub, port, &portstatus, &portchange);
                if (ret < 0) {
                        return -1;
                }

                /* Device went away? */
                if (!(portstatus & USB_PORT_STAT_CONNECTION))
                        return 1;

                /* bomb out completely if something weird happened */
                if ((portchange & USB_PORT_STAT_C_CONNECTION))
                        return -1;

                /* if we`ve finished resetting, then break out of the loop */
                if (!(portstatus & USB_PORT_STAT_RESET) &&
                    (portstatus & USB_PORT_STAT_ENABLE)) {
                        if (portstatus & USB_PORT_STAT_HIGH_SPEED)
                                dev->speed = USB_SPEED_HIGH;
                        else if (portstatus & USB_PORT_STAT_LOW_SPEED)
                                dev->speed = USB_SPEED_LOW;
                        else
                                dev->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 (hubdev (hub),
                        "port %d not reset yet, waiting %dms\n",
                        port + 1, delay);
        }

        return -1;
}

/* return: -1 on error, 0 on success, 1 on disconnect.  */
static int hub_port_reset(struct usb_device *hub, int port,
                                struct usb_device *dev, unsigned int delay)
{
        int i, status;

        /* Reset the port */
        for (i = 0; i < HUB_RESET_TRIES; i++) {
                set_port_feature(hub, port + 1, USB_PORT_FEAT_RESET);

                /* return on disconnect or reset */
                status = hub_port_wait_reset(hub, port, dev, delay);
                if (status != -1) {
                        clear_port_feature(hub,
                                port + 1, USB_PORT_FEAT_C_RESET);
                        dev->state = status
                                        ? USB_STATE_NOTATTACHED
                                        : USB_STATE_DEFAULT;
                        return status;
                }

                dev_dbg (hubdev (hub),
                        "port %d not enabled, trying reset again...\n",
                        port + 1);
                delay = HUB_LONG_RESET_TIME;
        }

        dev_err (hubdev (hub),
                "Cannot enable port %i.  Maybe the USB cable is bad?\n",
                port + 1);

        return -1;
}

int hub_port_disable(struct usb_device *hub, int port)
{
        int ret;

        ret = clear_port_feature(hub, port + 1, USB_PORT_FEAT_ENABLE);
        if (ret)
                dev_err(hubdev(hub), "cannot disable port %d (err = %d)\n",
                        port + 1, ret);

        return ret;
}

/* 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 which require longer delays of about 200-400ms.
 * Not covered by the spec - but easy to deal with.
 *
 * This implementation uses 400ms minimum debounce timeout and checks
 * every 25ms for transient disconnects to restart the delay.
 */


#define HUB_DEBOUNCE_TIMEOUT    400
#define HUB_DEBOUNCE_STEP        25
#define HUB_DEBOUNCE_STABLE       4

/* return: -1 on error, 0 on success, 1 on disconnect.  */
static int hub_port_debounce(struct usb_device *hub, int port)
{
        int ret;
        int delay_time, stable_count;
        u16 portchange, portstatus;
        unsigned connection;

        connection = 0;
        stable_count = 0;
        for (delay_time = 0; delay_time < HUB_DEBOUNCE_TIMEOUT; delay_time += HUB_DEBOUNCE_STEP) {
                wait_ms(HUB_DEBOUNCE_STEP);

                ret = hub_port_status(hub, port, &portstatus, &portchange);
                if (ret < 0)
                        return -1;

                if ((portstatus & USB_PORT_STAT_CONNECTION) == connection) {
                        if (connection) {
                                if (++stable_count == HUB_DEBOUNCE_STABLE)
                                        break;
                        }
                } else {
                        stable_count = 0;
                }
                connection = portstatus & USB_PORT_STAT_CONNECTION;

                if ((portchange & USB_PORT_STAT_C_CONNECTION)) {
                        clear_port_feature(hub, port+1, USB_PORT_FEAT_C_CONNECTION);
                }
        }

        dev_dbg (hubdev (hub),
                "debounce: port %d: delay %dms stable %d status 0x%x\n",
                port + 1, delay_time, stable_count, portstatus);

        return ((portstatus&USB_PORT_STAT_CONNECTION)) ? 0 : 1;
}

static void hub_port_connect_change(struct usb_hub *hubstate, int port,
                                        u16 portstatus, u16 portchange)
{
        struct usb_device *hub = interface_to_usbdev(hubstate->intf);
        struct usb_device *dev;
        unsigned int delay = HUB_SHORT_RESET_TIME;
        int i;

        dev_dbg (&hubstate->intf->dev,
                "port %d, status %x, change %x, %s\n",
                port + 1, portstatus, portchange, portspeed (portstatus));

        /* Clear the connection change status */
        clear_port_feature(hub, port + 1, USB_PORT_FEAT_C_CONNECTION);

        /* Disconnect any existing devices under this port */
        if (hub->children[port])
                usb_disconnect(&hub->children[port]);

        /* Return now if nothing is connected */
        if (!(portstatus & USB_PORT_STAT_CONNECTION)) {
                if (portstatus & USB_PORT_STAT_ENABLE)
                        hub_port_disable(hub, port);

                return;
        }

        if (hub_port_debounce(hub, port)) {
                dev_err (&hubstate->intf->dev,
                        "connect-debounce failed, port %d disabled\n",
                        port+1);
                hub_port_disable(hub, port);
                return;
        }

        /* root hub ports have a slightly longer reset period
         * (from USB 2.0 spec, section 7.1.7.5)
         */

        if (!hub->parent)
                delay = HUB_ROOT_RESET_TIME;

        /* Some low speed devices have problems with the quick delay, so */
        /*  be a bit pessimistic with those devices. RHbug #23670 */
        if (portstatus & USB_PORT_STAT_LOW_SPEED)
                delay = HUB_LONG_RESET_TIME;

        down(&usb_address0_sem);

        for (i = 0; i < HUB_PROBE_TRIES; i++) {
                struct usb_device *pdev;
                int     len;

                /* Allocate a new device struct */
                dev = usb_alloc_dev(hub, hub->bus);
                if (!dev) {
                        dev_err (&hubstate->intf->dev,
                                "couldn't allocate usb_device\n");
                        break;
                }

                dev->state = USB_STATE_POWERED;

                /* Reset the device, and detect its speed */
                if (hub_port_reset(hub, port, dev, delay)) {
                        usb_put_dev(dev);
                        break;
                }

                /* Find a new address for it */
                usb_choose_address(dev);

                /* Set up TT records, if needed  */
                if (hub->tt) {
                        dev->tt = hub->tt;
                        dev->ttport = hub->ttport;
                } else if (dev->speed != USB_SPEED_HIGH
                                && hub->speed == USB_SPEED_HIGH) {
                        dev->tt = &hubstate->tt;
                        dev->ttport = port + 1;
                }

                /* Save readable and stable topology id, distinguishing
                 * devices by location for diagnostics, tools, etc.  The
                 * string is a path along hub ports, from the root.  Each
                 * device's id will be stable until USB is re-cabled, and
                 * hubs are often labeled with these port numbers.
                 *
                 * Initial size: ".NN" times five hubs + NUL = 16 bytes max
                 * (quite rare, since most hubs have 4-6 ports).
                 */

                pdev = dev->parent;
                if (pdev->devpath [0] != '0')   /* parent not root? */
                        len = snprintf26(dev->devpath, sizeof dev->devpath,
                                "%s.%d", pdev->devpath, port + 1);
                /* root == "0", root port 2 == "2", port 3 that hub "2.3" */
                else
                        len = snprintf26(dev->devpath, sizeof dev->devpath,
                                "%d", port + 1);
                if (len == sizeof dev->devpath)
                        dev_err (&hubstate->intf->dev,
                                "devpath size! usb/%03d/%03d path %s\n",
                                dev->bus->busnum, dev->devnum, dev->devpath);
                dev_info (&hubstate->intf->dev,
                        "new USB device on port %d, assigned address %d\n",
                        port + 1, dev->devnum);

                /* put the device in the global device tree. the hub port
                 * is the "bus_id"; hubs show in hierarchy like bridges
                 */

                dev->dev.parent = dev->parent->dev.parent->parent;

                /* Run it through the hoops (find a driver, etc) */
                if (!usb_new_device(dev, &hub->dev)) {
                        hub->children[port] = dev;
                        goto done;
                }

                /* Free the configuration if there was an error */
                usb_put_dev(dev);

                /* Switch to a long reset time */
                delay = HUB_LONG_RESET_TIME;
        }

        hub_port_disable(hub, port);
done:
        up(&usb_address0_sem);
}

static void hub_events(void)
{
        unsigned long flags;
        struct list_head *tmp;
        struct usb_device *dev;
        struct usb_hub *hub;
        u16 hubstatus;
        u16 hubchange;
        u16 portstatus;
        u16 portchange;
        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) {
                spin_lock_irqsave(&hub_event_lock, flags);

                if (list_empty(&hub_event_list))
                        break;

                /* Grab the next entry from the beginning of the list */
                tmp = hub_event_list.next;

                hub = list_entry(tmp, struct usb_hub, event_list);
                dev = interface_to_usbdev(hub->intf);

                list_del_init(tmp);

//**                if (unlikely(down_trylock(&hub->khubd_sem)))
//**                        BUG();  /* never blocks, we were on list */

                spin_unlock_irqrestore(&hub_event_lock, flags);

                if (hub->error) {
                        dev_dbg (&hub->intf->dev, "resetting for error %d\n",
                                hub->error);

                        if (hub_reset(hub)) {
                                dev_dbg (&hub->intf->dev,
                                        "can't reset; disconnecting\n");
                                up(&hub->khubd_sem);
                                hub_start_disconnect(dev);
                                continue;
                        }

                        hub->nerrors = 0;
                        hub->error = 0;
                }

                for (i = 0; i < hub->descriptor->bNbrPorts; i++) {
                        ret = hub_port_status(dev, i, &portstatus, &portchange);
                        if (ret < 0) {
                                continue;
                        }

                        if (portchange & USB_PORT_STAT_C_CONNECTION) {
                                hub_port_connect_change(hub, i, portstatus, portchange);
                        } else if (portchange & USB_PORT_STAT_C_ENABLE) {
                                dev_dbg (hubdev (dev),
                                        "port %d enable change, status %x\n",
                                        i + 1, portstatus);
                                clear_port_feature(dev,
                                        i + 1, 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)
                                    && (portstatus & USB_PORT_STAT_CONNECTION)
                                    && (dev->children[i])) {
                                        dev_err (&hub->intf->dev,
                                            "port %i "
                                            "disabled by hub (EMI?), "
                                            "re-enabling...",
                                                i + 1);
                                        hub_port_connect_change(hub,
                                                i, portstatus, portchange);
                                }
                        }

                        if (portchange & USB_PORT_STAT_C_SUSPEND) {
                                dev_dbg (&hub->intf->dev,
                                        "suspend change on port %d\n",
                                        i + 1);
                                clear_port_feature(dev,
                                        i + 1,  USB_PORT_FEAT_C_SUSPEND);
                        }
                       
                        if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
                                dev_err (&hub->intf->dev,
                                        "over-current change on port %d\n",
                                        i + 1);
                                clear_port_feature(dev,
                                        i + 1, USB_PORT_FEAT_C_OVER_CURRENT);
                                hub_power_on(hub);
                        }

                        if (portchange & USB_PORT_STAT_C_RESET) {
                                dev_dbg (&hub->intf->dev,
                                        "reset change on port %d\n",
                                        i + 1);
                                clear_port_feature(dev,
                                        i + 1, USB_PORT_FEAT_C_RESET);
                        }
                } /* end for i */

                /* deal with hub status changes */
                if (hub_hub_status(hub, &hubstatus, &hubchange) < 0)
                        dev_err (&hub->intf->dev, "get_hub_status failed\n");
                else {
                        if (hubchange & HUB_CHANGE_LOCAL_POWER) {
                                dev_dbg (&hub->intf->dev, "power change\n");
                                clear_hub_feature(dev, C_HUB_LOCAL_POWER);
                        }
                        if (hubchange & HUB_CHANGE_OVERCURRENT) {
                                dev_dbg (&hub->intf->dev, "overcurrent change\n");
                                wait_ms(500);   /* Cool down */
                                clear_hub_feature(dev, C_HUB_OVER_CURRENT);
                                hub_power_on(hub);
                        }
                }
                up(&hub->khubd_sem);
        } /* end while (1) */

        spin_unlock_irqrestore(&hub_event_lock, flags);
}

static int hub_thread(void *__hub)
{
        /*
         * This thread doesn't need any user-level access,
         * so get rid of all our resources
         */


        daemonize("khubd");
        allow_signal(SIGKILL);

        /* Send me a signal to get me die (for debugging) */
        do {
                hub_events();
                wait_event_interruptible(khubd_wait, !list_empty(&hub_event_list));
//                if (current->flags & PF_FREEZE)
//                        refrigerator(PF_IOTHREAD);
        } while (!signal_pending(current));

        dbg("hub_thread exiting");
        complete_and_exit(&khubd_exited, 0);
        return 0;
}

static struct usb_device_id hub_id_table [] = {
    { .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 = {
        .owner =        THIS_MODULE,
        .name =         "hub",
        .probe =        hub_probe,
        .disconnect =   hub_disconnect,
        .ioctl =        hub_ioctl,
        .id_table =     hub_id_table,
};

/*
 * This should be a separate module.
 */

int usb_hub_init(void)
{
        pid_t pid;

        if (usb_register(&hub_driver) < 0) {
                err("Unable to register USB hub driver");
                return -1;
        }

        pid = kernel_thread(hub_thread, NULL, CLONE_KERNEL);
        if (pid >= 0) {
                khubd_pid = pid;

                return 0;
        }

        /* Fall through if kernel_thread failed */
        usb_deregister(&hub_driver);
        err("failed to start hub_thread");

        return -1;
}

void usb_hub_cleanup(void)
{
        int ret;

        /* Kill the thread */
        ret = kill_proc(khubd_pid, SIGKILL, 1);

        wait_for_completion(&khubd_exited);

        /*
         * 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() */

/*
 * WARNING - If a driver calls usb_reset_device, you should simulate a
 * disconnect() and probe() for other interfaces you doesn't claim. This
 * is left up to the driver writer right now. This insures other drivers
 * have a chance to re-setup their interface.
 *
 * Take a look at proc_resetdevice in devio.c for some sample code to
 * do this.
 * Use this only from within your probe function, otherwise use
 * usb_reset_device() below, which ensure proper locking
 */

int usb_physical_reset_device(struct usb_device *dev)
{
        struct usb_device *parent = dev->parent;
        struct usb_device_descriptor *descriptor;
        int i, ret, port = -1;

        if (!parent) {
                err("attempting to reset root hub!");
                return -EINVAL;
        }

        for (i = 0; i < parent->maxchild; i++)
                if (parent->children[i] == dev) {
                        port = i;
                        break;
                }

        if (port < 0)
                return -ENOENT;

        descriptor = kmalloc(sizeof *descriptor, GFP_NOIO);
        if (!descriptor) {
                return -ENOMEM;
        }

        down(&usb_address0_sem);

        /* Send a reset to the device */
        if (hub_port_reset(parent, port, dev, HUB_SHORT_RESET_TIME)) {
                hub_port_disable(parent, port);
                up(&usb_address0_sem);
                kfree(descriptor);
                return(-ENODEV);
        }

        /* Reprogram the Address */
        ret = usb_set_address(dev);
        if (ret < 0) {
                err("USB device not accepting new address (error=%d)", ret);
                hub_port_disable(parent, port);
                up(&usb_address0_sem);
                kfree(descriptor);
                return ret;
        }

        /* Let the SET_ADDRESS settle */
        wait_ms(10);

        up(&usb_address0_sem);

        /*
         * Now we fetch the configuration descriptors for the device and
         * see if anything has changed. If it has, we dump the current
         * parsed descriptors and reparse from scratch. Then we leave
         * the device alone for the caller to finish setting up.
         *
         * If nothing changed, we reprogram the configuration and then
         * the alternate settings.
         */


        ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, descriptor,
                        sizeof(*descriptor));
        if (ret < 0) {
                kfree(descriptor);
                return ret;
        }

        le16_to_cpus(&descriptor->bcdUSB);
        le16_to_cpus(&descriptor->idVendor);
        le16_to_cpus(&descriptor->idProduct);
        le16_to_cpus(&descriptor->bcdDevice);

        if (memcmp(&dev->descriptor, descriptor, sizeof(*descriptor))) {
                kfree(descriptor);
                usb_destroy_configuration(dev);

                ret = usb_get_device_descriptor(dev);
                if (ret < sizeof(dev->descriptor)) {
                        if (ret < 0)
                                err("unable to get device %s descriptor "
                                        "(error=%d)", dev->devpath, ret);
                        else
                                err("USB device %s descriptor short read "
                                        "(expected %Zi, got %i)",
                                        dev->devpath,
                                        sizeof(dev->descriptor), ret);

                        clear_bit(dev->devnum, dev->bus->devmap.devicemap);
                        dev->devnum = -1;
                        return -EIO;
                }

                ret = usb_get_configuration(dev);
                if (ret < 0) {
                        err("unable to get configuration (error=%d)", ret);
                        usb_destroy_configuration(dev);
                        clear_bit(dev->devnum, dev->bus->devmap.devicemap);
                        dev->devnum = -1;
                        return 1;
                }

                usb_set_configuration(dev, dev->config[0].desc.bConfigurationValue);
                return 1;
        }

        kfree(descriptor);

        ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                        USB_REQ_SET_CONFIGURATION, 0,
                        dev->actconfig->desc.bConfigurationValue, 0,
                        NULL, 0, HZ * USB_CTRL_SET_TIMEOUT);
        if (ret < 0) {
                err("failed to set dev %s active configuration (error=%d)",
                        dev->devpath, ret);
                return ret;
        }
        dev->state = USB_STATE_CONFIGURED;

        for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
                struct usb_interface *intf = dev->actconfig->interface[i];
                struct usb_interface_descriptor *as;

                as = &intf->altsetting[intf->act_altsetting].desc;
                ret = usb_set_interface(dev, as->bInterfaceNumber,
                        as->bAlternateSetting);
                if (ret < 0) {
                        err("failed to set active alternate setting "
                                "for dev %s interface %d (error=%d)",
                                dev->devpath, i, ret);
                        return ret;
                }
        }

        return 0;
}

int usb_reset_device(struct usb_device *udev)
{
        struct device *gdev = &udev->dev;
        int r;
       
//      down_read(&gdev->bus->subsys.rwsem);
        r = usb_physical_reset_device(udev);
//      up_read(&gdev->bus->subsys.rwsem);

        return r;
}