4 * This driver supports USB CDC WCM Device Management.
6 * Copyright (c) 2007-2009 Oliver Neukum
8 * Some code taken from cdc-acm.c
10 * Released under the GPLv2.
12 * Many thanks to Carl Nordbeck
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/uaccess.h>
20 #include <linux/bitops.h>
21 #include <linux/poll.h>
22 #include <linux/usb.h>
23 #include <linux/usb/cdc.h>
24 #include <asm/byteorder.h>
25 #include <asm/unaligned.h>
26 #include <linux/usb/cdc-wdm.h>
31 #define DRIVER_VERSION "v0.03"
32 #define DRIVER_AUTHOR "Oliver Neukum"
33 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
35 #define HUAWEI_VENDOR_ID 0x12D1
37 static const struct usb_device_id wdm_ids[] = {
39 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
40 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
41 .bInterfaceClass = USB_CLASS_COMM,
42 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
46 * Huawei E392, E398 and possibly other Qualcomm based modems
47 * embed the Qualcomm QMI protocol inside CDC on CDC ECM like
48 * control interfaces. Userspace access to this is required
49 * to configure the accompanying data interface
51 .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
52 USB_DEVICE_ID_MATCH_INT_INFO,
53 .idVendor = HUAWEI_VENDOR_ID,
54 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
55 .bInterfaceSubClass = 1,
56 .bInterfaceProtocol = 9, /* NOTE: CDC ECM control interface! */
61 MODULE_DEVICE_TABLE (usb, wdm_ids);
63 #define WDM_MINOR_BASE 176
67 #define WDM_DISCONNECTING 2
70 #define WDM_INT_STALL 5
71 #define WDM_POLL_RUNNING 6
72 #define WDM_RESPONDING 7
73 #define WDM_SUSPENDING 8
74 #define WDM_RESETTING 9
78 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
79 #define WDM_DEFAULT_BUFSIZE 256
81 static DEFINE_MUTEX(wdm_mutex);
82 static DEFINE_SPINLOCK(wdm_device_list_lock);
83 static LIST_HEAD(wdm_device_list);
85 /* --- method tables --- */
88 u8 *inbuf; /* buffer for response */
89 u8 *outbuf; /* buffer for command */
90 u8 *sbuf; /* buffer for status */
91 u8 *ubuf; /* buffer for copy to user space */
96 struct usb_interface *intf;
97 struct usb_ctrlrequest *orq;
98 struct usb_ctrlrequest *irq;
114 wait_queue_head_t wait;
115 struct work_struct rxwork;
119 struct list_head device_list;
120 int (*manage_power)(struct usb_interface *, int);
123 static struct usb_driver wdm_driver;
125 /* return intfdata if we own the interface, else look up intf in the list */
126 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
128 struct wdm_device *desc = NULL;
130 spin_lock(&wdm_device_list_lock);
131 list_for_each_entry(desc, &wdm_device_list, device_list)
132 if (desc->intf == intf)
134 spin_unlock(&wdm_device_list_lock);
139 static struct wdm_device *wdm_find_device_by_minor(int minor)
141 struct wdm_device *desc = NULL;
143 spin_lock(&wdm_device_list_lock);
144 list_for_each_entry(desc, &wdm_device_list, device_list)
145 if (desc->intf->minor == minor)
147 spin_unlock(&wdm_device_list_lock);
152 /* --- callbacks --- */
153 static void wdm_out_callback(struct urb *urb)
155 struct wdm_device *desc;
157 spin_lock(&desc->iuspin);
158 desc->werr = urb->status;
159 spin_unlock(&desc->iuspin);
162 clear_bit(WDM_IN_USE, &desc->flags);
163 wake_up(&desc->wait);
166 static void wdm_in_callback(struct urb *urb)
168 struct wdm_device *desc = urb->context;
169 int status = urb->status;
171 spin_lock(&desc->iuspin);
172 clear_bit(WDM_RESPONDING, &desc->flags);
177 dev_dbg(&desc->intf->dev,
178 "nonzero urb status received: -ENOENT");
181 dev_dbg(&desc->intf->dev,
182 "nonzero urb status received: -ECONNRESET");
185 dev_dbg(&desc->intf->dev,
186 "nonzero urb status received: -ESHUTDOWN");
189 dev_err(&desc->intf->dev,
190 "nonzero urb status received: -EPIPE\n");
193 dev_err(&desc->intf->dev,
194 "Unexpected error %d\n", status);
200 desc->reslength = urb->actual_length;
201 memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
202 desc->length += desc->reslength;
204 wake_up(&desc->wait);
206 set_bit(WDM_READ, &desc->flags);
207 spin_unlock(&desc->iuspin);
210 static void wdm_int_callback(struct urb *urb)
213 int status = urb->status;
214 struct wdm_device *desc;
215 struct usb_cdc_notification *dr;
218 dr = (struct usb_cdc_notification *)desc->sbuf;
227 set_bit(WDM_INT_STALL, &desc->flags);
228 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
229 goto sw; /* halt is cleared in work */
231 dev_err(&desc->intf->dev,
232 "nonzero urb status received: %d\n", status);
237 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
238 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
243 switch (dr->bNotificationType) {
244 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
245 dev_dbg(&desc->intf->dev,
246 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
247 dr->wIndex, dr->wLength);
250 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
252 dev_dbg(&desc->intf->dev,
253 "NOTIFY_NETWORK_CONNECTION %s network",
254 dr->wValue ? "connected to" : "disconnected from");
257 clear_bit(WDM_POLL_RUNNING, &desc->flags);
258 dev_err(&desc->intf->dev,
259 "unknown notification %d received: index %d len %d\n",
260 dr->bNotificationType, dr->wIndex, dr->wLength);
264 spin_lock(&desc->iuspin);
265 clear_bit(WDM_READ, &desc->flags);
266 set_bit(WDM_RESPONDING, &desc->flags);
267 if (!test_bit(WDM_DISCONNECTING, &desc->flags)
268 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
269 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
270 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
273 spin_unlock(&desc->iuspin);
275 clear_bit(WDM_RESPONDING, &desc->flags);
280 rv = schedule_work(&desc->rxwork);
282 dev_err(&desc->intf->dev,
283 "Cannot schedule work\n");
287 rv = usb_submit_urb(urb, GFP_ATOMIC);
289 dev_err(&desc->intf->dev,
290 "%s - usb_submit_urb failed with result %d\n",
295 static void kill_urbs(struct wdm_device *desc)
297 /* the order here is essential */
298 usb_kill_urb(desc->command);
299 usb_kill_urb(desc->validity);
300 usb_kill_urb(desc->response);
303 static void free_urbs(struct wdm_device *desc)
305 usb_free_urb(desc->validity);
306 usb_free_urb(desc->response);
307 usb_free_urb(desc->command);
310 static void cleanup(struct wdm_device *desc)
312 spin_lock(&wdm_device_list_lock);
313 list_del(&desc->device_list);
314 spin_unlock(&wdm_device_list_lock);
324 static ssize_t wdm_write
325 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
328 int rv = -EMSGSIZE, r, we;
329 struct wdm_device *desc = file->private_data;
330 struct usb_ctrlrequest *req;
332 if (count > desc->wMaxCommand)
333 count = desc->wMaxCommand;
335 spin_lock_irq(&desc->iuspin);
338 spin_unlock_irq(&desc->iuspin);
342 buf = kmalloc(count, GFP_KERNEL);
348 r = copy_from_user(buf, buffer, count);
355 /* concurrent writes and disconnect */
356 r = mutex_lock_interruptible(&desc->wlock);
363 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
369 r = usb_autopm_get_interface(desc->intf);
372 rv = usb_translate_errors(r);
376 if (!(file->f_flags & O_NONBLOCK))
377 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
380 if (test_bit(WDM_IN_USE, &desc->flags))
383 if (test_bit(WDM_RESETTING, &desc->flags))
393 usb_fill_control_urb(
395 interface_to_usbdev(desc->intf),
396 /* using common endpoint 0 */
397 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
398 (unsigned char *)req,
405 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
406 USB_RECIP_INTERFACE);
407 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
409 req->wIndex = desc->inum;
410 req->wLength = cpu_to_le16(count);
411 set_bit(WDM_IN_USE, &desc->flags);
414 rv = usb_submit_urb(desc->command, GFP_KERNEL);
418 clear_bit(WDM_IN_USE, &desc->flags);
419 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
420 rv = usb_translate_errors(rv);
422 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
426 usb_autopm_put_interface(desc->intf);
428 mutex_unlock(&desc->wlock);
430 return rv < 0 ? rv : count;
433 static ssize_t wdm_read
434 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
438 struct wdm_device *desc = file->private_data;
441 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
445 cntr = ACCESS_ONCE(desc->length);
449 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
454 if (file->f_flags & O_NONBLOCK) {
455 if (!test_bit(WDM_READ, &desc->flags)) {
456 rv = cntr ? cntr : -EAGAIN;
461 rv = wait_event_interruptible(desc->wait,
462 test_bit(WDM_READ, &desc->flags));
465 /* may have happened while we slept */
466 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
470 if (test_bit(WDM_RESETTING, &desc->flags)) {
474 usb_mark_last_busy(interface_to_usbdev(desc->intf));
480 spin_lock_irq(&desc->iuspin);
482 if (desc->rerr) { /* read completed, error happened */
484 spin_unlock_irq(&desc->iuspin);
489 * recheck whether we've lost the race
490 * against the completion handler
492 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
493 spin_unlock_irq(&desc->iuspin);
496 if (!desc->reslength) { /* zero length read */
497 spin_unlock_irq(&desc->iuspin);
501 spin_unlock_irq(&desc->iuspin);
506 rv = copy_to_user(buffer, desc->ubuf, cntr);
512 spin_lock_irq(&desc->iuspin);
514 for (i = 0; i < desc->length - cntr; i++)
515 desc->ubuf[i] = desc->ubuf[i + cntr];
517 desc->length -= cntr;
518 /* in case we had outstanding data */
520 clear_bit(WDM_READ, &desc->flags);
522 spin_unlock_irq(&desc->iuspin);
527 mutex_unlock(&desc->rlock);
531 static int wdm_flush(struct file *file, fl_owner_t id)
533 struct wdm_device *desc = file->private_data;
535 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
537 /* cannot dereference desc->intf if WDM_DISCONNECTING */
538 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
539 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
542 return usb_translate_errors(desc->werr);
545 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
547 struct wdm_device *desc = file->private_data;
549 unsigned int mask = 0;
551 spin_lock_irqsave(&desc->iuspin, flags);
552 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
553 mask = POLLHUP | POLLERR;
554 spin_unlock_irqrestore(&desc->iuspin, flags);
557 if (test_bit(WDM_READ, &desc->flags))
558 mask = POLLIN | POLLRDNORM;
559 if (desc->rerr || desc->werr)
561 if (!test_bit(WDM_IN_USE, &desc->flags))
562 mask |= POLLOUT | POLLWRNORM;
563 spin_unlock_irqrestore(&desc->iuspin, flags);
565 poll_wait(file, &desc->wait, wait);
571 static int wdm_open(struct inode *inode, struct file *file)
573 int minor = iminor(inode);
575 struct usb_interface *intf;
576 struct wdm_device *desc;
578 mutex_lock(&wdm_mutex);
579 desc = wdm_find_device_by_minor(minor);
584 if (test_bit(WDM_DISCONNECTING, &desc->flags))
586 file->private_data = desc;
588 rv = usb_autopm_get_interface(desc->intf);
590 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
594 /* using write lock to protect desc->count */
595 mutex_lock(&desc->wlock);
596 if (!desc->count++) {
599 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
602 dev_err(&desc->intf->dev,
603 "Error submitting int urb - %d\n", rv);
604 rv = usb_translate_errors(rv);
609 mutex_unlock(&desc->wlock);
610 if (desc->count == 1)
611 desc->manage_power(intf, 1);
612 usb_autopm_put_interface(desc->intf);
614 mutex_unlock(&wdm_mutex);
618 static int wdm_release(struct inode *inode, struct file *file)
620 struct wdm_device *desc = file->private_data;
622 mutex_lock(&wdm_mutex);
624 /* using write lock to protect desc->count */
625 mutex_lock(&desc->wlock);
627 mutex_unlock(&desc->wlock);
630 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
631 dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
633 desc->manage_power(desc->intf, 0);
635 /* must avoid dev_printk here as desc->intf is invalid */
636 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
640 mutex_unlock(&wdm_mutex);
644 static const struct file_operations wdm_fops = {
645 .owner = THIS_MODULE,
650 .release = wdm_release,
652 .llseek = noop_llseek,
655 static struct usb_class_driver wdm_class = {
658 .minor_base = WDM_MINOR_BASE,
661 /* --- error handling --- */
662 static void wdm_rxwork(struct work_struct *work)
664 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
668 spin_lock_irqsave(&desc->iuspin, flags);
669 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
670 spin_unlock_irqrestore(&desc->iuspin, flags);
672 spin_unlock_irqrestore(&desc->iuspin, flags);
673 rv = usb_submit_urb(desc->response, GFP_KERNEL);
674 if (rv < 0 && rv != -EPERM) {
675 spin_lock_irqsave(&desc->iuspin, flags);
676 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
677 schedule_work(&desc->rxwork);
678 spin_unlock_irqrestore(&desc->iuspin, flags);
683 /* --- hotplug --- */
685 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
686 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
689 struct wdm_device *desc;
691 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
694 INIT_LIST_HEAD(&desc->device_list);
695 mutex_init(&desc->rlock);
696 mutex_init(&desc->wlock);
697 spin_lock_init(&desc->iuspin);
698 init_waitqueue_head(&desc->wait);
699 desc->wMaxCommand = bufsize;
700 /* this will be expanded and needed in hardware endianness */
701 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
703 INIT_WORK(&desc->rxwork, wdm_rxwork);
706 if (!usb_endpoint_is_int_in(ep))
709 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
711 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
714 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
718 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
722 desc->response = usb_alloc_urb(0, GFP_KERNEL);
726 desc->command = usb_alloc_urb(0, GFP_KERNEL);
730 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
734 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
738 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
744 interface_to_usbdev(intf),
745 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
747 desc->wMaxPacketSize,
753 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
754 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
755 desc->irq->wValue = 0;
756 desc->irq->wIndex = desc->inum;
757 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
759 usb_fill_control_urb(
761 interface_to_usbdev(intf),
762 /* using common endpoint 0 */
763 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
764 (unsigned char *)desc->irq,
771 desc->manage_power = manage_power;
773 spin_lock(&wdm_device_list_lock);
774 list_add(&desc->device_list, &wdm_device_list);
775 spin_unlock(&wdm_device_list_lock);
777 rv = usb_register_dev(intf, &wdm_class);
781 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
789 static int wdm_manage_power(struct usb_interface *intf, int on)
791 /* need autopm_get/put here to ensure the usbcore sees the new value */
792 int rv = usb_autopm_get_interface(intf);
796 intf->needs_remote_wakeup = on;
797 usb_autopm_put_interface(intf);
802 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
805 struct usb_host_interface *iface;
806 struct usb_endpoint_descriptor *ep;
807 struct usb_cdc_dmm_desc *dmhd;
808 u8 *buffer = intf->altsetting->extra;
809 int buflen = intf->altsetting->extralen;
810 u16 maxcom = WDM_DEFAULT_BUFSIZE;
815 if (buffer[1] != USB_DT_CS_INTERFACE) {
816 dev_err(&intf->dev, "skipping garbage\n");
821 case USB_CDC_HEADER_TYPE:
823 case USB_CDC_DMM_TYPE:
824 dmhd = (struct usb_cdc_dmm_desc *)buffer;
825 maxcom = le16_to_cpu(dmhd->wMaxCommand);
827 "Finding maximum buffer length: %d", maxcom);
831 "Ignoring extra header, type %d, length %d\n",
832 buffer[2], buffer[0]);
840 iface = intf->cur_altsetting;
841 if (iface->desc.bNumEndpoints != 1)
843 ep = &iface->endpoint[0].desc;
845 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
852 * usb_cdc_wdm_register - register a WDM subdriver
853 * @intf: usb interface the subdriver will associate with
854 * @ep: interrupt endpoint to monitor for notifications
855 * @bufsize: maximum message size to support for read/write
857 * Create WDM usb class character device and associate it with intf
858 * without binding, allowing another driver to manage the interface.
860 * The subdriver will manage the given interrupt endpoint exclusively
861 * and will issue control requests referring to the given intf. It
862 * will otherwise avoid interferring, and in particular not do
863 * usb_set_intfdata/usb_get_intfdata on intf.
865 * The return value is a pointer to the subdriver's struct usb_driver.
866 * The registering driver is responsible for calling this subdriver's
867 * disconnect, suspend, resume, pre_reset and post_reset methods from
870 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
871 struct usb_endpoint_descriptor *ep,
873 int (*manage_power)(struct usb_interface *, int))
877 rv = wdm_create(intf, ep, bufsize, manage_power);
885 EXPORT_SYMBOL(usb_cdc_wdm_register);
887 static void wdm_disconnect(struct usb_interface *intf)
889 struct wdm_device *desc;
892 usb_deregister_dev(intf, &wdm_class);
893 desc = wdm_find_device(intf);
894 mutex_lock(&wdm_mutex);
896 /* the spinlock makes sure no new urbs are generated in the callbacks */
897 spin_lock_irqsave(&desc->iuspin, flags);
898 set_bit(WDM_DISCONNECTING, &desc->flags);
899 set_bit(WDM_READ, &desc->flags);
900 /* to terminate pending flushes */
901 clear_bit(WDM_IN_USE, &desc->flags);
902 spin_unlock_irqrestore(&desc->iuspin, flags);
903 wake_up_all(&desc->wait);
904 mutex_lock(&desc->rlock);
905 mutex_lock(&desc->wlock);
907 cancel_work_sync(&desc->rxwork);
908 mutex_unlock(&desc->wlock);
909 mutex_unlock(&desc->rlock);
913 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
914 mutex_unlock(&wdm_mutex);
918 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
920 struct wdm_device *desc = wdm_find_device(intf);
923 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
925 /* if this is an autosuspend the caller does the locking */
926 if (!PMSG_IS_AUTO(message)) {
927 mutex_lock(&desc->rlock);
928 mutex_lock(&desc->wlock);
930 spin_lock_irq(&desc->iuspin);
932 if (PMSG_IS_AUTO(message) &&
933 (test_bit(WDM_IN_USE, &desc->flags)
934 || test_bit(WDM_RESPONDING, &desc->flags))) {
935 spin_unlock_irq(&desc->iuspin);
939 set_bit(WDM_SUSPENDING, &desc->flags);
940 spin_unlock_irq(&desc->iuspin);
941 /* callback submits work - order is essential */
943 cancel_work_sync(&desc->rxwork);
945 if (!PMSG_IS_AUTO(message)) {
946 mutex_unlock(&desc->wlock);
947 mutex_unlock(&desc->rlock);
954 static int recover_from_urb_loss(struct wdm_device *desc)
959 rv = usb_submit_urb(desc->validity, GFP_NOIO);
961 dev_err(&desc->intf->dev,
962 "Error resume submitting int urb - %d\n", rv);
968 static int wdm_resume(struct usb_interface *intf)
970 struct wdm_device *desc = wdm_find_device(intf);
973 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
975 clear_bit(WDM_SUSPENDING, &desc->flags);
976 rv = recover_from_urb_loss(desc);
982 static int wdm_pre_reset(struct usb_interface *intf)
984 struct wdm_device *desc = wdm_find_device(intf);
987 * we notify everybody using poll of
988 * an exceptional situation
989 * must be done before recovery lest a spontaneous
990 * message from the device is lost
992 spin_lock_irq(&desc->iuspin);
993 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
994 set_bit(WDM_READ, &desc->flags); /* unblock read */
995 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
997 spin_unlock_irq(&desc->iuspin);
998 wake_up_all(&desc->wait);
999 mutex_lock(&desc->rlock);
1000 mutex_lock(&desc->wlock);
1002 cancel_work_sync(&desc->rxwork);
1006 static int wdm_post_reset(struct usb_interface *intf)
1008 struct wdm_device *desc = wdm_find_device(intf);
1011 clear_bit(WDM_RESETTING, &desc->flags);
1012 rv = recover_from_urb_loss(desc);
1013 mutex_unlock(&desc->wlock);
1014 mutex_unlock(&desc->rlock);
1018 static struct usb_driver wdm_driver = {
1021 .disconnect = wdm_disconnect,
1023 .suspend = wdm_suspend,
1024 .resume = wdm_resume,
1025 .reset_resume = wdm_resume,
1027 .pre_reset = wdm_pre_reset,
1028 .post_reset = wdm_post_reset,
1029 .id_table = wdm_ids,
1030 .supports_autosuspend = 1,
1033 module_usb_driver(wdm_driver);
1035 MODULE_AUTHOR(DRIVER_AUTHOR);
1036 MODULE_DESCRIPTION(DRIVER_DESC);
1037 MODULE_LICENSE("GPL");