USB: CDC WDM driver

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 761 insertions, 0 deletions

diff --git a/drivers/usb/class/Kconfig b/drivers/usb/class/Kconfig
index 3a9102d2591b..66f17ed88cb5 100644
--- a/drivers/usb/class/Kconfig
+++ b/drivers/usb/class/Kconfig
@@ -29,3 +29,14 @@ config USB_PRINTER
           To compile this driver as a module, choose M here: the
           module will be called usblp.
 
+config USB_WDM
+        tristate "USB Wireless Device Management support"
+        depends on USB
+        ---help---
+          This driver supports the WMC Device Management functionality
+          of cell phones compliant to the CDC WMC specification. You can use
+          AT commands over this device.
+
+          To compile this driver as a module, choose M here: the
+          module will be called cdc-wdm.
+
diff --git a/drivers/usb/class/Makefile b/drivers/usb/class/Makefile
index cc391e6c2af8..535d59a30600 100644
--- a/drivers/usb/class/Makefile
+++ b/drivers/usb/class/Makefile
@@ -5,3 +5,4 @@
 
 obj-$(CONFIG_USB_ACM)           += cdc-acm.o
 obj-$(CONFIG_USB_PRINTER)       += usblp.o
+obj-$(CONFIG_USB_WDM)           += cdc-wdm.o
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
new file mode 100644
index 000000000000..107666d4e2ec
--- /dev/null
+++ b/drivers/usb/class/cdc-wdm.c
@@ -0,0 +1,740 @@
+/*
+ * cdc-wdm.c
+ *
+ * This driver supports USB CDC WCM Device Management.
+ *
+ * Copyright (c) 2007-2008 Oliver Neukum
+ *
+ * Some code taken from cdc-acm.c
+ *
+ * Released under the GPLv2.
+ *
+ * Many thanks to Carl Nordbeck
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/poll.h>
+#include <linux/usb.h>
+#include <linux/usb/cdc.h>
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+
+/*
+ * Version Information
+ */
+#define DRIVER_VERSION "v0.02"
+#define DRIVER_AUTHOR "Oliver Neukum"
+
+static struct usb_device_id wdm_ids[] = {
+        {
+                .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
+                                 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
+                .bInterfaceClass = USB_CLASS_COMM,
+                .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
+        },
+        { }
+};
+
+#define WDM_MINOR_BASE  176
+
+
+#define WDM_IN_USE              1
+#define WDM_DISCONNECTING       2
+#define WDM_RESULT              3
+#define WDM_READ                4
+#define WDM_INT_STALL           5
+#define WDM_POLL_RUNNING        6
+
+
+#define WDM_MAX                 16
+
+
+static DEFINE_MUTEX(wdm_mutex);
+
+/* --- method tables --- */
+
+struct wdm_device {
+        u8                      *inbuf; /* buffer for response */
+        u8                      *outbuf; /* buffer for command */
+        u8                      *sbuf; /* buffer for status */
+        u8                      *ubuf; /* buffer for copy to user space */
+
+        struct urb              *command;
+        struct urb              *response;
+        struct urb              *validity;
+        struct usb_interface    *intf;
+        struct usb_ctrlrequest  *orq;
+        struct usb_ctrlrequest  *irq;
+        spinlock_t              iuspin;
+
+        unsigned long           flags;
+        u16                     bufsize;
+        u16                     wMaxCommand;
+        u16                     wMaxPacketSize;
+        u16                     bMaxPacketSize0;
+        __le16                  inum;
+        int                     reslength;
+        int                     length;
+        int                     read;
+        int                     count;
+        dma_addr_t              shandle;
+        dma_addr_t              ihandle;
+        struct mutex            wlock;
+        struct mutex            rlock;
+        wait_queue_head_t       wait;
+        struct work_struct      rxwork;
+        int                     werr;
+        int                     rerr;
+};
+
+static struct usb_driver wdm_driver;
+
+/* --- callbacks --- */
+static void wdm_out_callback(struct urb *urb)
+{
+        struct wdm_device *desc;
+        desc = urb->context;
+        spin_lock(&desc->iuspin);
+        desc->werr = urb->status;
+        spin_unlock(&desc->iuspin);
+        clear_bit(WDM_IN_USE, &desc->flags);
+        kfree(desc->outbuf);
+        wake_up(&desc->wait);
+}
+
+static void wdm_in_callback(struct urb *urb)
+{
+        struct wdm_device *desc = urb->context;
+        int status = urb->status;
+
+        spin_lock(&desc->iuspin);
+
+        if (status) {
+                switch (status) {
+                case -ENOENT:
+                        dev_dbg(&desc->intf->dev,
+                                "nonzero urb status received: -ENOENT");
+                        break;
+                case -ECONNRESET:
+                        dev_dbg(&desc->intf->dev,
+                                "nonzero urb status received: -ECONNRESET");
+                        break;
+                case -ESHUTDOWN:
+                        dev_dbg(&desc->intf->dev,
+                                "nonzero urb status received: -ESHUTDOWN");
+                        break;
+                case -EPIPE:
+                        err("nonzero urb status received: -EPIPE");
+                        break;
+                default:
+                        err("Unexpected error %d", status);
+                        break;
+                }
+        }
+
+        desc->rerr = status;
+        desc->reslength = urb->actual_length;
+        memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
+        desc->length += desc->reslength;
+        wake_up(&desc->wait);
+
+        set_bit(WDM_READ, &desc->flags);
+        spin_unlock(&desc->iuspin);
+}
+
+static void wdm_int_callback(struct urb *urb)
+{
+        int rv = 0;
+        int status = urb->status;
+        struct wdm_device *desc;
+        struct usb_ctrlrequest *req;
+        struct usb_cdc_notification *dr;
+
+        desc = urb->context;
+        req = desc->irq;
+        dr = (struct usb_cdc_notification *)desc->sbuf;
+
+        if (status) {
+                switch (status) {
+                case -ESHUTDOWN:
+                case -ENOENT:
+                case -ECONNRESET:
+                        return; /* unplug */
+                case -EPIPE:
+                        set_bit(WDM_INT_STALL, &desc->flags);
+                        err("Stall on int endpoint");
+                        goto sw; /* halt is cleared in work */
+                default:
+                        err("nonzero urb status received: %d", status);
+                        break;
+                }
+        }
+
+        if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
+                err("wdm_int_callback - %d bytes", urb->actual_length);
+                goto exit;
+        }
+
+        switch (dr->bNotificationType) {
+        case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
+                dev_dbg(&desc->intf->dev,
+                        "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
+                        dr->wIndex, dr->wLength);
+                break;
+
+        case USB_CDC_NOTIFY_NETWORK_CONNECTION:
+
+                dev_dbg(&desc->intf->dev,
+                        "NOTIFY_NETWORK_CONNECTION %s network",
+                        dr->wValue ? "connected to" : "disconnected from");
+                goto exit;
+        default:
+                clear_bit(WDM_POLL_RUNNING, &desc->flags);
+                err("unknown notification %d received: index %d len %d",
+                        dr->bNotificationType, dr->wIndex, dr->wLength);
+                goto exit;
+        }
+
+        req->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
+        req->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
+        req->wValue = 0;
+        req->wIndex = desc->inum;
+        req->wLength = cpu_to_le16(desc->bMaxPacketSize0);
+
+        usb_fill_control_urb(
+                desc->response,
+                interface_to_usbdev(desc->intf),
+                /* using common endpoint 0 */
+                usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
+                (unsigned char *)req,
+                desc->inbuf,
+                desc->bMaxPacketSize0,
+                wdm_in_callback,
+                desc
+        );
+        desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+        spin_lock(&desc->iuspin);
+        clear_bit(WDM_READ, &desc->flags);
+        if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
+                rv = usb_submit_urb(desc->response, GFP_ATOMIC);
+                dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
+                        __func__, rv);
+        }
+        spin_unlock(&desc->iuspin);
+        if (rv < 0) {
+                if (rv == -EPERM)
+                        return;
+                if (rv == -ENOMEM) {
+sw:
+                        rv = schedule_work(&desc->rxwork);
+                        if (rv)
+                                err("Cannot schedule work");
+                }
+        }
+exit:
+        rv = usb_submit_urb(urb, GFP_ATOMIC);
+        if (rv)
+                err("%s - usb_submit_urb failed with result %d",
+                     __func__, rv);
+
+}
+
+static void kill_urbs(struct wdm_device *desc)
+{
+        usb_kill_urb(desc->command);
+        usb_kill_urb(desc->validity);
+        usb_kill_urb(desc->response);
+}
+
+static void free_urbs(struct wdm_device *desc)
+{
+        usb_free_urb(desc->validity);
+        usb_free_urb(desc->response);
+        usb_free_urb(desc->command);
+}
+
+static void cleanup(struct wdm_device *desc)
+{
+        usb_buffer_free(interface_to_usbdev(desc->intf),
+                        desc->wMaxPacketSize,
+                        desc->sbuf,
+                        desc->validity->transfer_dma);
+        usb_buffer_free(interface_to_usbdev(desc->intf),
+                        desc->wMaxPacketSize,
+                        desc->inbuf,
+                        desc->response->transfer_dma);
+        kfree(desc->orq);
+        kfree(desc->irq);
+        kfree(desc->ubuf);
+        free_urbs(desc);
+        kfree(desc);
+}
+
+static ssize_t wdm_write
+(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
+{
+        u8 *buf;
+        int rv = -EMSGSIZE, r, we;
+        struct wdm_device *desc = file->private_data;
+        struct usb_ctrlrequest *req;
+
+        if (count > desc->wMaxCommand)
+                count = desc->wMaxCommand;
+
+        spin_lock_irq(&desc->iuspin);
+        we = desc->werr;
+        desc->werr = 0;
+        spin_unlock_irq(&desc->iuspin);
+        if (we < 0)
+                return -EIO;
+
+        r = mutex_lock_interruptible(&desc->wlock); /* concurrent writes */
+        rv = -ERESTARTSYS;
+        if (r)
+                goto outnl;
+
+        r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
+                                                           &desc->flags));
+        if (r < 0)
+                goto out;
+
+        if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
+                rv = -ENODEV;
+                goto out;
+        }
+
+        desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
+        if (!buf) {
+                rv = -ENOMEM;
+                goto out;
+        }
+
+        r = copy_from_user(buf, buffer, count);
+        if (r > 0) {
+                kfree(buf);
+                rv = -EFAULT;
+                goto out;
+        }
+
+        req = desc->orq;
+        usb_fill_control_urb(
+                desc->command,
+                interface_to_usbdev(desc->intf),
+                /* using common endpoint 0 */
+                usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
+                (unsigned char *)req,
+                buf,
+                count,
+                wdm_out_callback,
+                desc
+        );
+
+        req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
+                             USB_RECIP_INTERFACE);
+        req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
+        req->wValue = 0;
+        req->wIndex = desc->inum;
+        req->wLength = cpu_to_le16(count);
+        set_bit(WDM_IN_USE, &desc->flags);
+
+        rv = usb_submit_urb(desc->command, GFP_KERNEL);
+        if (rv < 0) {
+                kfree(buf);
+                clear_bit(WDM_IN_USE, &desc->flags);
+        } else {
+                dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
+                        req->wIndex);
+        }
+out:
+        mutex_unlock(&desc->wlock);
+outnl:
+        return rv < 0 ? rv : count;
+}
+
+static ssize_t wdm_read
+(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
+{
+        int rv, cntr;
+        int i = 0;
+        struct wdm_device *desc = file->private_data;
+
+
+        rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
+        if (rv < 0)
+                return -ERESTARTSYS;
+
+        if (desc->length == 0) {
+                desc->read = 0;
+retry:
+                i++;
+                rv = wait_event_interruptible(desc->wait,
+                                              test_bit(WDM_READ, &desc->flags));
+
+                if (rv < 0) {
+                        rv = -ERESTARTSYS;
+                        goto err;
+                }
+
+                spin_lock_irq(&desc->iuspin);
+
+                if (desc->rerr) { /* read completed, error happened */
+                        int t = desc->rerr;
+                        desc->rerr = 0;
+                        spin_unlock_irq(&desc->iuspin);
+                        err("reading had resulted in %d", t);
+                        rv = -EIO;
+                        goto err;
+                }
+                /*
+                 * recheck whether we've lost the race
+                 * against the completion handler
+                 */
+                if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
+                        spin_unlock_irq(&desc->iuspin);
+                        goto retry;
+                }
+                if (!desc->reslength) { /* zero length read */
+                        spin_unlock_irq(&desc->iuspin);
+                        goto retry;
+                }
+                clear_bit(WDM_READ, &desc->flags);
+                spin_unlock_irq(&desc->iuspin);
+        }
+
+        cntr = count > desc->length ? desc->length : count;
+        rv = copy_to_user(buffer, desc->ubuf, cntr);
+        if (rv > 0) {
+                rv = -EFAULT;
+                goto err;
+        }
+
+        for (i = 0; i < desc->length - cntr; i++)
+                desc->ubuf[i] = desc->ubuf[i + cntr];
+
+        desc->length -= cntr;
+        rv = cntr;
+
+err:
+        mutex_unlock(&desc->rlock);
+        if (rv < 0)
+                err("wdm_read: exit error");
+        return rv;
+}
+
+static int wdm_flush(struct file *file, fl_owner_t id)
+{
+        struct wdm_device *desc = file->private_data;
+
+        wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
+        if (desc->werr < 0)
+                err("Error in flush path: %d", desc->werr);
+
+        return desc->werr;
+}
+
+static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
+{
+        struct wdm_device *desc = file->private_data;
+        unsigned long flags;
+        unsigned int mask = 0;
+
+        spin_lock_irqsave(&desc->iuspin, flags);
+        if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
+                mask = POLLERR;
+                spin_unlock_irqrestore(&desc->iuspin, flags);
+                goto desc_out;
+        }
+        if (test_bit(WDM_READ, &desc->flags))
+                mask = POLLIN | POLLRDNORM;
+        if (desc->rerr || desc->werr)
+                mask |= POLLERR;
+        if (!test_bit(WDM_IN_USE, &desc->flags))
+                mask |= POLLOUT | POLLWRNORM;
+        spin_unlock_irqrestore(&desc->iuspin, flags);
+
+        poll_wait(file, &desc->wait, wait);
+
+desc_out:
+        return mask;
+}
+
+static int wdm_open(struct inode *inode, struct file *file)
+{
+        int minor = iminor(inode);
+        int rv = -ENODEV;
+        struct usb_interface *intf;
+        struct wdm_device *desc;
+
+        mutex_lock(&wdm_mutex);
+        intf = usb_find_interface(&wdm_driver, minor);
+        if (!intf)
+                goto out;
+
+        desc = usb_get_intfdata(intf);
+        if (test_bit(WDM_DISCONNECTING, &desc->flags))
+                goto out;
+
+        desc->count++;
+        file->private_data = desc;
+
+        rv = usb_submit_urb(desc->validity, GFP_KERNEL);
+
+        if (rv < 0) {
+                desc->count--;
+                err("Error submitting int urb - %d", rv);
+                goto out;
+        }
+        rv = 0;
+
+out:
+        mutex_unlock(&wdm_mutex);
+        return rv;
+}
+
+static int wdm_release(struct inode *inode, struct file *file)
+{
+        struct wdm_device *desc = file->private_data;
+
+        mutex_lock(&wdm_mutex);
+        desc->count--;
+        if (!desc->count) {
+                dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
+                kill_urbs(desc);
+        }
+        mutex_unlock(&wdm_mutex);
+        return 0;
+}
+
+static const struct file_operations wdm_fops = {
+        .owner =        THIS_MODULE,
+        .read =         wdm_read,
+        .write =        wdm_write,
+        .open =         wdm_open,
+        .flush =        wdm_flush,
+        .release =      wdm_release,
+        .poll =         wdm_poll
+};
+
+static struct usb_class_driver wdm_class = {
+        .name =         "cdc-wdm%d",
+        .fops =         &wdm_fops,
+        .minor_base =   WDM_MINOR_BASE,
+};
+
+/* --- error handling --- */
+static void wdm_rxwork(struct work_struct *work)
+{
+        struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
+        unsigned long flags;
+        int rv;
+
+        spin_lock_irqsave(&desc->iuspin, flags);
+        if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
+                spin_unlock_irqrestore(&desc->iuspin, flags);
+        } else {
+                spin_unlock_irqrestore(&desc->iuspin, flags);
+                rv = usb_submit_urb(desc->response, GFP_KERNEL);
+                if (rv < 0 && rv != -EPERM) {
+                        spin_lock_irqsave(&desc->iuspin, flags);
+                        if (!test_bit(WDM_DISCONNECTING, &desc->flags))
+                                schedule_work(&desc->rxwork);
+                        spin_unlock_irqrestore(&desc->iuspin, flags);
+                }
+        }
+}
+
+/* --- hotplug --- */
+
+static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+        int rv = -EINVAL;
+        struct usb_device *udev = interface_to_usbdev(intf);
+        struct wdm_device *desc;
+        struct usb_host_interface *iface;
+        struct usb_endpoint_descriptor *ep;
+        struct usb_cdc_dmm_desc *dmhd;
+        u8 *buffer = intf->altsetting->extra;
+        int buflen = intf->altsetting->extralen;
+        u16 maxcom = 0;
+
+        if (!buffer)
+                goto out;
+
+        while (buflen > 0) {
+                if (buffer [1] != USB_DT_CS_INTERFACE) {
+                        err("skipping garbage");
+                        goto next_desc;
+                }
+
+                switch (buffer [2]) {
+                case USB_CDC_HEADER_TYPE:
+                        break;
+                case USB_CDC_DMM_TYPE:
+                        dmhd = (struct usb_cdc_dmm_desc *)buffer;
+                        maxcom = le16_to_cpu(dmhd->wMaxCommand);
+                        dev_dbg(&intf->dev,
+                                "Finding maximum buffer length: %d", maxcom);
+                        break;
+                default:
+                        err("Ignoring extra header, type %d, length %d",
+                                buffer[2], buffer[0]);
+                        break;
+                }
+next_desc:
+                buflen -= buffer[0];
+                buffer += buffer[0];
+        }
+
+        rv = -ENOMEM;
+        desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
+        if (!desc)
+                goto out;
+        mutex_init(&desc->wlock);
+        mutex_init(&desc->rlock);
+        spin_lock_init(&desc->iuspin);
+        init_waitqueue_head(&desc->wait);
+        desc->wMaxCommand = maxcom;
+        desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
+        desc->intf = intf;
+        INIT_WORK(&desc->rxwork, wdm_rxwork);
+
+        iface = &intf->altsetting[0];
+        ep = &iface->endpoint[0].desc;
+        if (!usb_endpoint_is_int_in(ep)) {
+                rv = -EINVAL;
+                goto err;
+        }
+
+        desc->wMaxPacketSize = ep->wMaxPacketSize;
+        desc->bMaxPacketSize0 = cpu_to_le16(udev->descriptor.bMaxPacketSize0);
+
+        desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+        if (!desc->orq)
+                goto err;
+        desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+        if (!desc->irq)
+                goto err;
+
+        desc->validity = usb_alloc_urb(0, GFP_KERNEL);
+        if (!desc->validity)
+                goto err;
+
+        desc->response = usb_alloc_urb(0, GFP_KERNEL);
+        if (!desc->response)
+                goto err;
+
+        desc->command = usb_alloc_urb(0, GFP_KERNEL);
+        if (!desc->command)
+                goto err;
+
+        desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
+        if (!desc->ubuf)
+                goto err;
+
+        desc->sbuf = usb_buffer_alloc(interface_to_usbdev(intf),
+                                        desc->wMaxPacketSize,
+                                        GFP_KERNEL,
+                                        &desc->validity->transfer_dma);
+        if (!desc->sbuf)
+                goto err;
+
+        desc->inbuf = usb_buffer_alloc(interface_to_usbdev(intf),
+                                        desc->bMaxPacketSize0,
+                                        GFP_KERNEL,
+                                        &desc->response->transfer_dma);
+        if (!desc->inbuf)
+                goto err2;
+
+        usb_fill_int_urb(
+                desc->validity,
+                interface_to_usbdev(intf),
+                usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
+                desc->sbuf,
+                desc->wMaxPacketSize,
+                wdm_int_callback,
+                desc,
+                ep->bInterval
+        );
+        desc->validity->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+        usb_set_intfdata(intf, desc);
+        rv = usb_register_dev(intf, &wdm_class);
+        dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",
+                 intf->minor - WDM_MINOR_BASE);
+        if (rv < 0)
+                goto err;
+out:
+        return rv;
+err2:
+        usb_buffer_free(interface_to_usbdev(desc->intf),
+                        desc->wMaxPacketSize,
+                        desc->sbuf,
+                        desc->validity->transfer_dma);
+err:
+        free_urbs(desc);
+        kfree(desc->ubuf);
+        kfree(desc->orq);
+        kfree(desc->irq);
+        kfree(desc);
+        return rv;
+}
+
+static void wdm_disconnect(struct usb_interface *intf)
+{
+        struct wdm_device *desc;
+        unsigned long flags;
+
+        usb_deregister_dev(intf, &wdm_class);
+        mutex_lock(&wdm_mutex);
+        desc = usb_get_intfdata(intf);
+
+        /* the spinlock makes sure no new urbs are generated in the callbacks */
+        spin_lock_irqsave(&desc->iuspin, flags);
+        set_bit(WDM_DISCONNECTING, &desc->flags);
+        set_bit(WDM_READ, &desc->flags);
+        clear_bit(WDM_IN_USE, &desc->flags);
+        spin_unlock_irqrestore(&desc->iuspin, flags);
+        cancel_work_sync(&desc->rxwork);
+        kill_urbs(desc);
+        wake_up_all(&desc->wait);
+        if (!desc->count)
+                cleanup(desc);
+        mutex_unlock(&wdm_mutex);
+}
+
+static struct usb_driver wdm_driver = {
+        .name =         "cdc_wdm",
+        .probe =        wdm_probe,
+        .disconnect =   wdm_disconnect,
+        .id_table =     wdm_ids,
+};
+
+/* --- low level module stuff --- */
+
+static int __init wdm_init(void)
+{
+        int rv;
+
+        rv = usb_register(&wdm_driver);
+
+        return rv;
+}
+
+static void __exit wdm_exit(void)
+{
+        usb_deregister(&wdm_driver);
+}
+
+module_init(wdm_init);
+module_exit(wdm_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION("USB Abstract Control Model driver for "
+                   "USB WCM Device Management");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/usb/cdc.h b/include/linux/usb/cdc.h
index 71e52f2f6a38..ca228bb94218 100644
--- a/include/linux/usb/cdc.h
+++ b/include/linux/usb/cdc.h
@@ -130,6 +130,15 @@ struct usb_cdc_ether_desc {
         __u8    bNumberPowerFilters;
 } __attribute__ ((packed));
 
+/* "Telephone Control Model Functional Descriptor" from CDC WMC spec 6.3..3 */
+struct usb_cdc_dmm_desc {
+        __u8    bFunctionLength;
+        __u8    bDescriptorType;
+        __u8    bDescriptorSubtype;
+        __u16   bcdVersion;
+        __le16  wMaxCommand;
+} __attribute__ ((packed));
+
 /* "MDLM Functional Descriptor" from CDC WMC spec 6.7.2.3 */
 struct usb_cdc_mdlm_desc {
         __u8    bLength;