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 static const struct usb_device_id wdm_ids[] = {
37 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
38 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
39 .bInterfaceClass = USB_CLASS_COMM,
40 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
45 MODULE_DEVICE_TABLE (usb, wdm_ids);
47 #define WDM_MINOR_BASE 176
51 #define WDM_DISCONNECTING 2
54 #define WDM_INT_STALL 5
55 #define WDM_POLL_RUNNING 6
56 #define WDM_RESPONDING 7
57 #define WDM_SUSPENDING 8
58 #define WDM_RESETTING 9
59 #define WDM_OVERFLOW 10
63 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
64 #define WDM_DEFAULT_BUFSIZE 256
66 static DEFINE_MUTEX(wdm_mutex);
67 static DEFINE_SPINLOCK(wdm_device_list_lock);
68 static LIST_HEAD(wdm_device_list);
70 /* --- method tables --- */
73 u8 *inbuf; /* buffer for response */
74 u8 *outbuf; /* buffer for command */
75 u8 *sbuf; /* buffer for status */
76 u8 *ubuf; /* buffer for copy to user space */
81 struct usb_interface *intf;
82 struct usb_ctrlrequest *orq;
83 struct usb_ctrlrequest *irq;
99 wait_queue_head_t wait;
100 struct work_struct rxwork;
104 struct list_head device_list;
105 int (*manage_power)(struct usb_interface *, int);
108 static struct usb_driver wdm_driver;
110 /* return intfdata if we own the interface, else look up intf in the list */
111 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
113 struct wdm_device *desc;
115 spin_lock(&wdm_device_list_lock);
116 list_for_each_entry(desc, &wdm_device_list, device_list)
117 if (desc->intf == intf)
121 spin_unlock(&wdm_device_list_lock);
126 static struct wdm_device *wdm_find_device_by_minor(int minor)
128 struct wdm_device *desc;
130 spin_lock(&wdm_device_list_lock);
131 list_for_each_entry(desc, &wdm_device_list, device_list)
132 if (desc->intf->minor == minor)
136 spin_unlock(&wdm_device_list_lock);
141 /* --- callbacks --- */
142 static void wdm_out_callback(struct urb *urb)
144 struct wdm_device *desc;
146 spin_lock(&desc->iuspin);
147 desc->werr = urb->status;
148 spin_unlock(&desc->iuspin);
151 clear_bit(WDM_IN_USE, &desc->flags);
152 wake_up(&desc->wait);
155 static void wdm_in_callback(struct urb *urb)
157 struct wdm_device *desc = urb->context;
158 int status = urb->status;
159 int length = urb->actual_length;
161 spin_lock(&desc->iuspin);
162 clear_bit(WDM_RESPONDING, &desc->flags);
167 dev_dbg(&desc->intf->dev,
168 "nonzero urb status received: -ENOENT");
171 dev_dbg(&desc->intf->dev,
172 "nonzero urb status received: -ECONNRESET");
175 dev_dbg(&desc->intf->dev,
176 "nonzero urb status received: -ESHUTDOWN");
179 dev_err(&desc->intf->dev,
180 "nonzero urb status received: -EPIPE\n");
183 dev_err(&desc->intf->dev,
184 "Unexpected error %d\n", status);
190 if (length + desc->length > desc->wMaxCommand) {
191 /* The buffer would overflow */
192 set_bit(WDM_OVERFLOW, &desc->flags);
194 /* we may already be in overflow */
195 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
196 memmove(desc->ubuf + desc->length, desc->inbuf, length);
197 desc->length += length;
198 desc->reslength = length;
202 wake_up(&desc->wait);
204 set_bit(WDM_READ, &desc->flags);
205 spin_unlock(&desc->iuspin);
208 static void wdm_int_callback(struct urb *urb)
211 int status = urb->status;
212 struct wdm_device *desc;
213 struct usb_cdc_notification *dr;
216 dr = (struct usb_cdc_notification *)desc->sbuf;
225 set_bit(WDM_INT_STALL, &desc->flags);
226 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
227 goto sw; /* halt is cleared in work */
229 dev_err(&desc->intf->dev,
230 "nonzero urb status received: %d\n", status);
235 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
236 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
241 switch (dr->bNotificationType) {
242 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
243 dev_dbg(&desc->intf->dev,
244 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
245 dr->wIndex, dr->wLength);
248 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
250 dev_dbg(&desc->intf->dev,
251 "NOTIFY_NETWORK_CONNECTION %s network",
252 dr->wValue ? "connected to" : "disconnected from");
255 clear_bit(WDM_POLL_RUNNING, &desc->flags);
256 dev_err(&desc->intf->dev,
257 "unknown notification %d received: index %d len %d\n",
258 dr->bNotificationType, dr->wIndex, dr->wLength);
262 spin_lock(&desc->iuspin);
263 clear_bit(WDM_READ, &desc->flags);
264 set_bit(WDM_RESPONDING, &desc->flags);
265 if (!test_bit(WDM_DISCONNECTING, &desc->flags)
266 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
267 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
268 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
271 spin_unlock(&desc->iuspin);
273 clear_bit(WDM_RESPONDING, &desc->flags);
278 rv = schedule_work(&desc->rxwork);
280 dev_err(&desc->intf->dev,
281 "Cannot schedule work\n");
285 rv = usb_submit_urb(urb, GFP_ATOMIC);
287 dev_err(&desc->intf->dev,
288 "%s - usb_submit_urb failed with result %d\n",
293 static void kill_urbs(struct wdm_device *desc)
295 /* the order here is essential */
296 usb_kill_urb(desc->command);
297 usb_kill_urb(desc->validity);
298 usb_kill_urb(desc->response);
301 static void free_urbs(struct wdm_device *desc)
303 usb_free_urb(desc->validity);
304 usb_free_urb(desc->response);
305 usb_free_urb(desc->command);
308 static void cleanup(struct wdm_device *desc)
319 static ssize_t wdm_write
320 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
323 int rv = -EMSGSIZE, r, we;
324 struct wdm_device *desc = file->private_data;
325 struct usb_ctrlrequest *req;
327 if (count > desc->wMaxCommand)
328 count = desc->wMaxCommand;
330 spin_lock_irq(&desc->iuspin);
333 spin_unlock_irq(&desc->iuspin);
337 buf = kmalloc(count, GFP_KERNEL);
343 r = copy_from_user(buf, buffer, count);
350 /* concurrent writes and disconnect */
351 r = mutex_lock_interruptible(&desc->wlock);
358 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
364 r = usb_autopm_get_interface(desc->intf);
367 rv = usb_translate_errors(r);
371 if (!(file->f_flags & O_NONBLOCK))
372 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
375 if (test_bit(WDM_IN_USE, &desc->flags))
378 if (test_bit(WDM_RESETTING, &desc->flags))
388 usb_fill_control_urb(
390 interface_to_usbdev(desc->intf),
391 /* using common endpoint 0 */
392 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
393 (unsigned char *)req,
400 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
401 USB_RECIP_INTERFACE);
402 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
404 req->wIndex = desc->inum;
405 req->wLength = cpu_to_le16(count);
406 set_bit(WDM_IN_USE, &desc->flags);
409 rv = usb_submit_urb(desc->command, GFP_KERNEL);
413 clear_bit(WDM_IN_USE, &desc->flags);
414 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
415 rv = usb_translate_errors(rv);
417 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
421 usb_autopm_put_interface(desc->intf);
423 mutex_unlock(&desc->wlock);
425 return rv < 0 ? rv : count;
428 static ssize_t wdm_read
429 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
433 struct wdm_device *desc = file->private_data;
436 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
440 cntr = ACCESS_ONCE(desc->length);
444 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
448 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
449 clear_bit(WDM_OVERFLOW, &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);
497 if (!desc->reslength) { /* zero length read */
498 dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
499 clear_bit(WDM_READ, &desc->flags);
500 spin_unlock_irq(&desc->iuspin);
504 spin_unlock_irq(&desc->iuspin);
509 rv = copy_to_user(buffer, desc->ubuf, cntr);
515 spin_lock_irq(&desc->iuspin);
517 for (i = 0; i < desc->length - cntr; i++)
518 desc->ubuf[i] = desc->ubuf[i + cntr];
520 desc->length -= cntr;
521 /* in case we had outstanding data */
523 clear_bit(WDM_READ, &desc->flags);
525 spin_unlock_irq(&desc->iuspin);
530 mutex_unlock(&desc->rlock);
534 static int wdm_flush(struct file *file, fl_owner_t id)
536 struct wdm_device *desc = file->private_data;
538 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
540 /* cannot dereference desc->intf if WDM_DISCONNECTING */
541 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
542 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
545 return usb_translate_errors(desc->werr);
548 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
550 struct wdm_device *desc = file->private_data;
552 unsigned int mask = 0;
554 spin_lock_irqsave(&desc->iuspin, flags);
555 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
556 mask = POLLHUP | POLLERR;
557 spin_unlock_irqrestore(&desc->iuspin, flags);
560 if (test_bit(WDM_READ, &desc->flags))
561 mask = POLLIN | POLLRDNORM;
562 if (desc->rerr || desc->werr)
564 if (!test_bit(WDM_IN_USE, &desc->flags))
565 mask |= POLLOUT | POLLWRNORM;
566 spin_unlock_irqrestore(&desc->iuspin, flags);
568 poll_wait(file, &desc->wait, wait);
574 static int wdm_open(struct inode *inode, struct file *file)
576 int minor = iminor(inode);
578 struct usb_interface *intf;
579 struct wdm_device *desc;
581 mutex_lock(&wdm_mutex);
582 desc = wdm_find_device_by_minor(minor);
587 if (test_bit(WDM_DISCONNECTING, &desc->flags))
589 file->private_data = desc;
591 rv = usb_autopm_get_interface(desc->intf);
593 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
597 /* using write lock to protect desc->count */
598 mutex_lock(&desc->wlock);
599 if (!desc->count++) {
602 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
605 dev_err(&desc->intf->dev,
606 "Error submitting int urb - %d\n", rv);
607 rv = usb_translate_errors(rv);
612 mutex_unlock(&desc->wlock);
613 if (desc->count == 1)
614 desc->manage_power(intf, 1);
615 usb_autopm_put_interface(desc->intf);
617 mutex_unlock(&wdm_mutex);
621 static int wdm_release(struct inode *inode, struct file *file)
623 struct wdm_device *desc = file->private_data;
625 mutex_lock(&wdm_mutex);
627 /* using write lock to protect desc->count */
628 mutex_lock(&desc->wlock);
630 mutex_unlock(&desc->wlock);
633 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
634 dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
636 desc->manage_power(desc->intf, 0);
638 /* must avoid dev_printk here as desc->intf is invalid */
639 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
643 mutex_unlock(&wdm_mutex);
647 static const struct file_operations wdm_fops = {
648 .owner = THIS_MODULE,
653 .release = wdm_release,
655 .llseek = noop_llseek,
658 static struct usb_class_driver wdm_class = {
661 .minor_base = WDM_MINOR_BASE,
664 /* --- error handling --- */
665 static void wdm_rxwork(struct work_struct *work)
667 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
671 spin_lock_irqsave(&desc->iuspin, flags);
672 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
673 spin_unlock_irqrestore(&desc->iuspin, flags);
675 spin_unlock_irqrestore(&desc->iuspin, flags);
676 rv = usb_submit_urb(desc->response, GFP_KERNEL);
677 if (rv < 0 && rv != -EPERM) {
678 spin_lock_irqsave(&desc->iuspin, flags);
679 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
680 schedule_work(&desc->rxwork);
681 spin_unlock_irqrestore(&desc->iuspin, flags);
686 /* --- hotplug --- */
688 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
689 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
692 struct wdm_device *desc;
694 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
697 INIT_LIST_HEAD(&desc->device_list);
698 mutex_init(&desc->rlock);
699 mutex_init(&desc->wlock);
700 spin_lock_init(&desc->iuspin);
701 init_waitqueue_head(&desc->wait);
702 desc->wMaxCommand = bufsize;
703 /* this will be expanded and needed in hardware endianness */
704 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
706 INIT_WORK(&desc->rxwork, wdm_rxwork);
709 if (!usb_endpoint_is_int_in(ep))
712 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
714 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
717 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
721 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
725 desc->response = usb_alloc_urb(0, GFP_KERNEL);
729 desc->command = usb_alloc_urb(0, GFP_KERNEL);
733 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
737 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
741 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
747 interface_to_usbdev(intf),
748 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
750 desc->wMaxPacketSize,
756 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
757 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
758 desc->irq->wValue = 0;
759 desc->irq->wIndex = desc->inum;
760 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
762 usb_fill_control_urb(
764 interface_to_usbdev(intf),
765 /* using common endpoint 0 */
766 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
767 (unsigned char *)desc->irq,
774 desc->manage_power = manage_power;
776 spin_lock(&wdm_device_list_lock);
777 list_add(&desc->device_list, &wdm_device_list);
778 spin_unlock(&wdm_device_list_lock);
780 rv = usb_register_dev(intf, &wdm_class);
784 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
788 spin_lock(&wdm_device_list_lock);
789 list_del(&desc->device_list);
790 spin_unlock(&wdm_device_list_lock);
795 static int wdm_manage_power(struct usb_interface *intf, int on)
797 /* need autopm_get/put here to ensure the usbcore sees the new value */
798 int rv = usb_autopm_get_interface(intf);
802 intf->needs_remote_wakeup = on;
803 usb_autopm_put_interface(intf);
808 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
811 struct usb_host_interface *iface;
812 struct usb_endpoint_descriptor *ep;
813 struct usb_cdc_dmm_desc *dmhd;
814 u8 *buffer = intf->altsetting->extra;
815 int buflen = intf->altsetting->extralen;
816 u16 maxcom = WDM_DEFAULT_BUFSIZE;
821 if (buffer[1] != USB_DT_CS_INTERFACE) {
822 dev_err(&intf->dev, "skipping garbage\n");
827 case USB_CDC_HEADER_TYPE:
829 case USB_CDC_DMM_TYPE:
830 dmhd = (struct usb_cdc_dmm_desc *)buffer;
831 maxcom = le16_to_cpu(dmhd->wMaxCommand);
833 "Finding maximum buffer length: %d", maxcom);
837 "Ignoring extra header, type %d, length %d\n",
838 buffer[2], buffer[0]);
846 iface = intf->cur_altsetting;
847 if (iface->desc.bNumEndpoints != 1)
849 ep = &iface->endpoint[0].desc;
851 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
858 * usb_cdc_wdm_register - register a WDM subdriver
859 * @intf: usb interface the subdriver will associate with
860 * @ep: interrupt endpoint to monitor for notifications
861 * @bufsize: maximum message size to support for read/write
863 * Create WDM usb class character device and associate it with intf
864 * without binding, allowing another driver to manage the interface.
866 * The subdriver will manage the given interrupt endpoint exclusively
867 * and will issue control requests referring to the given intf. It
868 * will otherwise avoid interferring, and in particular not do
869 * usb_set_intfdata/usb_get_intfdata on intf.
871 * The return value is a pointer to the subdriver's struct usb_driver.
872 * The registering driver is responsible for calling this subdriver's
873 * disconnect, suspend, resume, pre_reset and post_reset methods from
876 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
877 struct usb_endpoint_descriptor *ep,
879 int (*manage_power)(struct usb_interface *, int))
883 rv = wdm_create(intf, ep, bufsize, manage_power);
891 EXPORT_SYMBOL(usb_cdc_wdm_register);
893 static void wdm_disconnect(struct usb_interface *intf)
895 struct wdm_device *desc;
898 usb_deregister_dev(intf, &wdm_class);
899 desc = wdm_find_device(intf);
900 mutex_lock(&wdm_mutex);
902 /* the spinlock makes sure no new urbs are generated in the callbacks */
903 spin_lock_irqsave(&desc->iuspin, flags);
904 set_bit(WDM_DISCONNECTING, &desc->flags);
905 set_bit(WDM_READ, &desc->flags);
906 /* to terminate pending flushes */
907 clear_bit(WDM_IN_USE, &desc->flags);
908 spin_unlock_irqrestore(&desc->iuspin, flags);
909 wake_up_all(&desc->wait);
910 mutex_lock(&desc->rlock);
911 mutex_lock(&desc->wlock);
913 cancel_work_sync(&desc->rxwork);
914 mutex_unlock(&desc->wlock);
915 mutex_unlock(&desc->rlock);
917 /* the desc->intf pointer used as list key is now invalid */
918 spin_lock(&wdm_device_list_lock);
919 list_del(&desc->device_list);
920 spin_unlock(&wdm_device_list_lock);
925 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
926 mutex_unlock(&wdm_mutex);
930 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
932 struct wdm_device *desc = wdm_find_device(intf);
935 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
937 /* if this is an autosuspend the caller does the locking */
938 if (!PMSG_IS_AUTO(message)) {
939 mutex_lock(&desc->rlock);
940 mutex_lock(&desc->wlock);
942 spin_lock_irq(&desc->iuspin);
944 if (PMSG_IS_AUTO(message) &&
945 (test_bit(WDM_IN_USE, &desc->flags)
946 || test_bit(WDM_RESPONDING, &desc->flags))) {
947 spin_unlock_irq(&desc->iuspin);
951 set_bit(WDM_SUSPENDING, &desc->flags);
952 spin_unlock_irq(&desc->iuspin);
953 /* callback submits work - order is essential */
955 cancel_work_sync(&desc->rxwork);
957 if (!PMSG_IS_AUTO(message)) {
958 mutex_unlock(&desc->wlock);
959 mutex_unlock(&desc->rlock);
966 static int recover_from_urb_loss(struct wdm_device *desc)
971 rv = usb_submit_urb(desc->validity, GFP_NOIO);
973 dev_err(&desc->intf->dev,
974 "Error resume submitting int urb - %d\n", rv);
980 static int wdm_resume(struct usb_interface *intf)
982 struct wdm_device *desc = wdm_find_device(intf);
985 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
987 clear_bit(WDM_SUSPENDING, &desc->flags);
988 rv = recover_from_urb_loss(desc);
994 static int wdm_pre_reset(struct usb_interface *intf)
996 struct wdm_device *desc = wdm_find_device(intf);
999 * we notify everybody using poll of
1000 * an exceptional situation
1001 * must be done before recovery lest a spontaneous
1002 * message from the device is lost
1004 spin_lock_irq(&desc->iuspin);
1005 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1006 set_bit(WDM_READ, &desc->flags); /* unblock read */
1007 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1008 desc->rerr = -EINTR;
1009 spin_unlock_irq(&desc->iuspin);
1010 wake_up_all(&desc->wait);
1011 mutex_lock(&desc->rlock);
1012 mutex_lock(&desc->wlock);
1014 cancel_work_sync(&desc->rxwork);
1018 static int wdm_post_reset(struct usb_interface *intf)
1020 struct wdm_device *desc = wdm_find_device(intf);
1023 clear_bit(WDM_OVERFLOW, &desc->flags);
1024 clear_bit(WDM_RESETTING, &desc->flags);
1025 rv = recover_from_urb_loss(desc);
1026 mutex_unlock(&desc->wlock);
1027 mutex_unlock(&desc->rlock);
1031 static struct usb_driver wdm_driver = {
1034 .disconnect = wdm_disconnect,
1036 .suspend = wdm_suspend,
1037 .resume = wdm_resume,
1038 .reset_resume = wdm_resume,
1040 .pre_reset = wdm_pre_reset,
1041 .post_reset = wdm_post_reset,
1042 .id_table = wdm_ids,
1043 .supports_autosuspend = 1,
1044 .disable_hub_initiated_lpm = 1,
1047 module_usb_driver(wdm_driver);
1049 MODULE_AUTHOR(DRIVER_AUTHOR);
1050 MODULE_DESCRIPTION(DRIVER_DESC);
1051 MODULE_LICENSE("GPL");