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/ioctl.h>
17 #include <linux/slab.h>
18 #include <linux/module.h>
19 #include <linux/mutex.h>
20 #include <linux/uaccess.h>
21 #include <linux/bitops.h>
22 #include <linux/poll.h>
23 #include <linux/usb.h>
24 #include <linux/usb/cdc.h>
25 #include <asm/byteorder.h>
26 #include <asm/unaligned.h>
27 #include <linux/usb/cdc-wdm.h>
32 #define DRIVER_VERSION "v0.03"
33 #define DRIVER_AUTHOR "Oliver Neukum"
34 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
36 static const struct usb_device_id wdm_ids[] = {
38 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
39 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
40 .bInterfaceClass = USB_CLASS_COMM,
41 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
46 MODULE_DEVICE_TABLE (usb, wdm_ids);
48 #define WDM_MINOR_BASE 176
52 #define WDM_DISCONNECTING 2
55 #define WDM_INT_STALL 5
56 #define WDM_POLL_RUNNING 6
57 #define WDM_RESPONDING 7
58 #define WDM_SUSPENDING 8
59 #define WDM_RESETTING 9
60 #define WDM_OVERFLOW 10
61 #define WDM_DRAIN_ON_OPEN 11
65 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
66 #define WDM_DEFAULT_BUFSIZE 256
68 static DEFINE_MUTEX(wdm_mutex);
69 static DEFINE_SPINLOCK(wdm_device_list_lock);
70 static LIST_HEAD(wdm_device_list);
72 /* --- method tables --- */
75 u8 *inbuf; /* buffer for response */
76 u8 *outbuf; /* buffer for command */
77 u8 *sbuf; /* buffer for status */
78 u8 *ubuf; /* buffer for copy to user space */
83 struct usb_interface *intf;
84 struct usb_ctrlrequest *orq;
85 struct usb_ctrlrequest *irq;
101 wait_queue_head_t wait;
102 struct work_struct rxwork;
107 struct list_head device_list;
108 int (*manage_power)(struct usb_interface *, int);
111 static struct usb_driver wdm_driver;
113 /* return intfdata if we own the interface, else look up intf in the list */
114 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
116 struct wdm_device *desc;
118 spin_lock(&wdm_device_list_lock);
119 list_for_each_entry(desc, &wdm_device_list, device_list)
120 if (desc->intf == intf)
124 spin_unlock(&wdm_device_list_lock);
129 static struct wdm_device *wdm_find_device_by_minor(int minor)
131 struct wdm_device *desc;
133 spin_lock(&wdm_device_list_lock);
134 list_for_each_entry(desc, &wdm_device_list, device_list)
135 if (desc->intf->minor == minor)
139 spin_unlock(&wdm_device_list_lock);
144 /* --- callbacks --- */
145 static void wdm_out_callback(struct urb *urb)
147 struct wdm_device *desc;
149 spin_lock(&desc->iuspin);
150 desc->werr = urb->status;
151 spin_unlock(&desc->iuspin);
154 clear_bit(WDM_IN_USE, &desc->flags);
155 wake_up(&desc->wait);
158 /* forward declaration */
159 static int service_outstanding_interrupt(struct wdm_device *desc);
161 static void wdm_in_callback(struct urb *urb)
163 struct wdm_device *desc = urb->context;
164 int status = urb->status;
165 int length = urb->actual_length;
167 spin_lock(&desc->iuspin);
168 clear_bit(WDM_RESPONDING, &desc->flags);
173 dev_dbg(&desc->intf->dev,
174 "nonzero urb status received: -ENOENT\n");
177 dev_dbg(&desc->intf->dev,
178 "nonzero urb status received: -ECONNRESET\n");
181 dev_dbg(&desc->intf->dev,
182 "nonzero urb status received: -ESHUTDOWN\n");
185 dev_dbg(&desc->intf->dev,
186 "nonzero urb status received: -EPIPE\n");
189 dev_err(&desc->intf->dev,
190 "Unexpected error %d\n", status);
196 * only set a new error if there is no previous error.
197 * Errors are only cleared during read/open
202 if (length + desc->length > desc->wMaxCommand) {
203 /* The buffer would overflow */
204 set_bit(WDM_OVERFLOW, &desc->flags);
206 /* we may already be in overflow */
207 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
208 memmove(desc->ubuf + desc->length, desc->inbuf, length);
209 desc->length += length;
210 desc->reslength = length;
215 * Handling devices with the WDM_DRAIN_ON_OPEN flag set:
216 * If desc->resp_count is unset, then the urb was submitted
217 * without a prior notification. If the device returned any
218 * data, then this implies that it had messages queued without
219 * notifying us. Continue reading until that queue is flushed.
221 if (!desc->resp_count) {
223 /* do not propagate the expected -EPIPE */
227 dev_dbg(&desc->intf->dev, "got %d bytes without notification\n", length);
228 set_bit(WDM_RESPONDING, &desc->flags);
229 usb_submit_urb(desc->response, GFP_ATOMIC);
233 set_bit(WDM_READ, &desc->flags);
234 wake_up(&desc->wait);
238 * Since there was an error, userspace may decide to not read
239 * any data after poll'ing.
240 * We should respond to further attempts from the device to send
241 * data, so that we can get unstuck.
243 service_outstanding_interrupt(desc);
247 spin_unlock(&desc->iuspin);
250 static void wdm_int_callback(struct urb *urb)
254 int status = urb->status;
255 struct wdm_device *desc;
256 struct usb_cdc_notification *dr;
259 dr = (struct usb_cdc_notification *)desc->sbuf;
268 set_bit(WDM_INT_STALL, &desc->flags);
269 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
270 goto sw; /* halt is cleared in work */
272 dev_err(&desc->intf->dev,
273 "nonzero urb status received: %d\n", status);
278 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
279 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
284 switch (dr->bNotificationType) {
285 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
286 dev_dbg(&desc->intf->dev,
287 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
288 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
291 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
293 dev_dbg(&desc->intf->dev,
294 "NOTIFY_NETWORK_CONNECTION %s network\n",
295 dr->wValue ? "connected to" : "disconnected from");
297 case USB_CDC_NOTIFY_SPEED_CHANGE:
298 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
302 clear_bit(WDM_POLL_RUNNING, &desc->flags);
303 dev_err(&desc->intf->dev,
304 "unknown notification %d received: index %d len %d\n",
305 dr->bNotificationType,
306 le16_to_cpu(dr->wIndex),
307 le16_to_cpu(dr->wLength));
311 spin_lock(&desc->iuspin);
312 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
313 if (!desc->resp_count++ && !responding
314 && !test_bit(WDM_DISCONNECTING, &desc->flags)
315 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
316 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
317 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
319 spin_unlock(&desc->iuspin);
321 clear_bit(WDM_RESPONDING, &desc->flags);
326 rv = schedule_work(&desc->rxwork);
328 dev_err(&desc->intf->dev,
329 "Cannot schedule work\n");
333 rv = usb_submit_urb(urb, GFP_ATOMIC);
335 dev_err(&desc->intf->dev,
336 "%s - usb_submit_urb failed with result %d\n",
341 static void kill_urbs(struct wdm_device *desc)
343 /* the order here is essential */
344 usb_kill_urb(desc->command);
345 usb_kill_urb(desc->validity);
346 usb_kill_urb(desc->response);
349 static void free_urbs(struct wdm_device *desc)
351 usb_free_urb(desc->validity);
352 usb_free_urb(desc->response);
353 usb_free_urb(desc->command);
356 static void cleanup(struct wdm_device *desc)
367 static ssize_t wdm_write
368 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
371 int rv = -EMSGSIZE, r, we;
372 struct wdm_device *desc = file->private_data;
373 struct usb_ctrlrequest *req;
375 if (count > desc->wMaxCommand)
376 count = desc->wMaxCommand;
378 spin_lock_irq(&desc->iuspin);
381 spin_unlock_irq(&desc->iuspin);
383 return usb_translate_errors(we);
385 buf = kmalloc(count, GFP_KERNEL);
391 r = copy_from_user(buf, buffer, count);
397 /* concurrent writes and disconnect */
398 r = mutex_lock_interruptible(&desc->wlock);
403 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
405 goto out_free_mem_lock;
408 r = usb_autopm_get_interface(desc->intf);
410 rv = usb_translate_errors(r);
411 goto out_free_mem_lock;
414 if (!(file->f_flags & O_NONBLOCK))
415 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
418 if (test_bit(WDM_IN_USE, &desc->flags))
421 if (test_bit(WDM_RESETTING, &desc->flags))
426 goto out_free_mem_pm;
430 usb_fill_control_urb(
432 interface_to_usbdev(desc->intf),
433 /* using common endpoint 0 */
434 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
435 (unsigned char *)req,
442 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
443 USB_RECIP_INTERFACE);
444 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
446 req->wIndex = desc->inum; /* already converted */
447 req->wLength = cpu_to_le16(count);
448 set_bit(WDM_IN_USE, &desc->flags);
451 rv = usb_submit_urb(desc->command, GFP_KERNEL);
454 clear_bit(WDM_IN_USE, &desc->flags);
455 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
456 rv = usb_translate_errors(rv);
457 goto out_free_mem_pm;
459 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
460 le16_to_cpu(req->wIndex));
463 usb_autopm_put_interface(desc->intf);
464 mutex_unlock(&desc->wlock);
466 return rv < 0 ? rv : count;
469 usb_autopm_put_interface(desc->intf);
471 mutex_unlock(&desc->wlock);
478 * Submit the read urb if resp_count is non-zero.
480 * Called with desc->iuspin locked
482 static int service_outstanding_interrupt(struct wdm_device *desc)
486 /* submit read urb only if the device is waiting for it */
487 if (!desc->resp_count || !--desc->resp_count)
490 set_bit(WDM_RESPONDING, &desc->flags);
491 spin_unlock_irq(&desc->iuspin);
492 rv = usb_submit_urb(desc->response, GFP_KERNEL);
493 spin_lock_irq(&desc->iuspin);
495 dev_err(&desc->intf->dev,
496 "usb_submit_urb failed with result %d\n", rv);
498 /* make sure the next notification trigger a submit */
499 clear_bit(WDM_RESPONDING, &desc->flags);
500 desc->resp_count = 0;
506 static ssize_t wdm_read
507 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
511 struct wdm_device *desc = file->private_data;
514 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
518 cntr = ACCESS_ONCE(desc->length);
522 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
526 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
527 clear_bit(WDM_OVERFLOW, &desc->flags);
532 if (file->f_flags & O_NONBLOCK) {
533 if (!test_bit(WDM_READ, &desc->flags)) {
539 rv = wait_event_interruptible(desc->wait,
540 test_bit(WDM_READ, &desc->flags));
543 /* may have happened while we slept */
544 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
548 if (test_bit(WDM_RESETTING, &desc->flags)) {
552 usb_mark_last_busy(interface_to_usbdev(desc->intf));
558 spin_lock_irq(&desc->iuspin);
560 if (desc->rerr) { /* read completed, error happened */
561 rv = usb_translate_errors(desc->rerr);
563 spin_unlock_irq(&desc->iuspin);
567 * recheck whether we've lost the race
568 * against the completion handler
570 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
571 spin_unlock_irq(&desc->iuspin);
575 if (!desc->reslength) { /* zero length read */
576 dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
577 clear_bit(WDM_READ, &desc->flags);
578 rv = service_outstanding_interrupt(desc);
579 spin_unlock_irq(&desc->iuspin);
585 spin_unlock_irq(&desc->iuspin);
590 rv = copy_to_user(buffer, desc->ubuf, cntr);
596 spin_lock_irq(&desc->iuspin);
598 for (i = 0; i < desc->length - cntr; i++)
599 desc->ubuf[i] = desc->ubuf[i + cntr];
601 desc->length -= cntr;
602 /* in case we had outstanding data */
604 clear_bit(WDM_READ, &desc->flags);
605 service_outstanding_interrupt(desc);
607 spin_unlock_irq(&desc->iuspin);
611 mutex_unlock(&desc->rlock);
615 static int wdm_flush(struct file *file, fl_owner_t id)
617 struct wdm_device *desc = file->private_data;
619 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
621 /* cannot dereference desc->intf if WDM_DISCONNECTING */
622 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
623 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
626 return usb_translate_errors(desc->werr);
629 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
631 struct wdm_device *desc = file->private_data;
633 unsigned int mask = 0;
635 spin_lock_irqsave(&desc->iuspin, flags);
636 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
637 mask = POLLHUP | POLLERR;
638 spin_unlock_irqrestore(&desc->iuspin, flags);
641 if (test_bit(WDM_READ, &desc->flags))
642 mask = POLLIN | POLLRDNORM;
643 if (desc->rerr || desc->werr)
645 if (!test_bit(WDM_IN_USE, &desc->flags))
646 mask |= POLLOUT | POLLWRNORM;
647 spin_unlock_irqrestore(&desc->iuspin, flags);
649 poll_wait(file, &desc->wait, wait);
655 static int wdm_open(struct inode *inode, struct file *file)
657 int minor = iminor(inode);
659 struct usb_interface *intf;
660 struct wdm_device *desc;
662 mutex_lock(&wdm_mutex);
663 desc = wdm_find_device_by_minor(minor);
668 if (test_bit(WDM_DISCONNECTING, &desc->flags))
670 file->private_data = desc;
672 rv = usb_autopm_get_interface(desc->intf);
674 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
678 /* using write lock to protect desc->count */
679 mutex_lock(&desc->wlock);
680 if (!desc->count++) {
683 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
686 dev_err(&desc->intf->dev,
687 "Error submitting int urb - %d\n", rv);
688 rv = usb_translate_errors(rv);
689 } else if (test_bit(WDM_DRAIN_ON_OPEN, &desc->flags)) {
691 * Some devices keep pending messages queued
692 * without resending notifications. We must
693 * flush the message queue before we can
694 * assume a one-to-one relationship between
695 * notifications and messages in the queue
697 dev_dbg(&desc->intf->dev, "draining queued data\n");
698 set_bit(WDM_RESPONDING, &desc->flags);
699 rv = usb_submit_urb(desc->response, GFP_KERNEL);
704 mutex_unlock(&desc->wlock);
705 if (desc->count == 1)
706 desc->manage_power(intf, 1);
707 usb_autopm_put_interface(desc->intf);
709 mutex_unlock(&wdm_mutex);
713 static int wdm_release(struct inode *inode, struct file *file)
715 struct wdm_device *desc = file->private_data;
717 mutex_lock(&wdm_mutex);
719 /* using write lock to protect desc->count */
720 mutex_lock(&desc->wlock);
722 mutex_unlock(&desc->wlock);
725 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
726 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
728 spin_lock_irq(&desc->iuspin);
729 desc->resp_count = 0;
730 spin_unlock_irq(&desc->iuspin);
731 desc->manage_power(desc->intf, 0);
733 /* must avoid dev_printk here as desc->intf is invalid */
734 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
738 mutex_unlock(&wdm_mutex);
742 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
744 struct wdm_device *desc = file->private_data;
748 case IOCTL_WDM_MAX_COMMAND:
749 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
758 static const struct file_operations wdm_fops = {
759 .owner = THIS_MODULE,
764 .release = wdm_release,
766 .unlocked_ioctl = wdm_ioctl,
767 .compat_ioctl = wdm_ioctl,
768 .llseek = noop_llseek,
771 static struct usb_class_driver wdm_class = {
774 .minor_base = WDM_MINOR_BASE,
777 /* --- error handling --- */
778 static void wdm_rxwork(struct work_struct *work)
780 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
785 spin_lock_irqsave(&desc->iuspin, flags);
786 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
787 spin_unlock_irqrestore(&desc->iuspin, flags);
789 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
790 spin_unlock_irqrestore(&desc->iuspin, flags);
792 rv = usb_submit_urb(desc->response, GFP_KERNEL);
793 if (rv < 0 && rv != -EPERM) {
794 spin_lock_irqsave(&desc->iuspin, flags);
795 clear_bit(WDM_RESPONDING, &desc->flags);
796 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
797 schedule_work(&desc->rxwork);
798 spin_unlock_irqrestore(&desc->iuspin, flags);
803 /* --- hotplug --- */
805 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
806 u16 bufsize, int (*manage_power)(struct usb_interface *, int),
810 struct wdm_device *desc;
812 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
815 INIT_LIST_HEAD(&desc->device_list);
816 mutex_init(&desc->rlock);
817 mutex_init(&desc->wlock);
818 spin_lock_init(&desc->iuspin);
819 init_waitqueue_head(&desc->wait);
820 desc->wMaxCommand = bufsize;
821 /* this will be expanded and needed in hardware endianness */
822 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
824 INIT_WORK(&desc->rxwork, wdm_rxwork);
827 if (!usb_endpoint_is_int_in(ep))
830 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
832 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
835 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
839 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
843 desc->response = usb_alloc_urb(0, GFP_KERNEL);
847 desc->command = usb_alloc_urb(0, GFP_KERNEL);
851 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
855 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
859 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
865 interface_to_usbdev(intf),
866 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
868 desc->wMaxPacketSize,
874 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
875 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
876 desc->irq->wValue = 0;
877 desc->irq->wIndex = desc->inum; /* already converted */
878 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
880 usb_fill_control_urb(
882 interface_to_usbdev(intf),
883 /* using common endpoint 0 */
884 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
885 (unsigned char *)desc->irq,
892 desc->manage_power = manage_power;
895 * "drain_on_open" enables a hack to work around a firmware
896 * issue observed on network functions, in particular MBIM
899 * Quoting section 7 of the CDC-WMC r1.1 specification:
901 * "The firmware shall interpret GetEncapsulatedResponse as a
902 * request to read response bytes. The firmware shall send
903 * the next wLength bytes from the response. The firmware
904 * shall allow the host to retrieve data using any number of
905 * GetEncapsulatedResponse requests. The firmware shall
906 * return a zero- length reply if there are no data bytes
909 * The firmware shall send ResponseAvailable notifications
910 * periodically, using any appropriate algorithm, to inform
911 * the host that there is data available in the reply
912 * buffer. The firmware is allowed to send ResponseAvailable
913 * notifications even if there is no data available, but
914 * this will obviously reduce overall performance."
916 * These requirements, although they make equally sense, are
917 * often not implemented by network functions. Some firmwares
918 * will queue data indefinitely, without ever resending a
919 * notification. The result is that the driver and firmware
920 * loses "syncronization" if the driver ever fails to respond
921 * to a single notification, something which easily can happen
922 * on release(). When this happens, the driver will appear to
923 * never receive notifications for the most current data. Each
924 * notification will only cause a single read, which returns
925 * the oldest data in the firmware's queue.
927 * The "drain_on_open" hack resolves the situation by draining
928 * data from the firmware until none is returned, without a
929 * prior notification.
931 * This will inevitably race with the firmware, risking that
932 * we read data from the device before handling the associated
933 * notification. To make things worse, some of the devices
934 * needing the hack do not implement the "return zero if no
935 * data is available" requirement either. Instead they return
936 * an error on the subsequent read in this case. This means
937 * that "winning" the race can cause an unexpected EIO to
940 * "winning" the race is more likely on resume() than on
941 * open(), and the unexpected error is more harmful in the
942 * middle of an open session. The hack is therefore only
943 * applied on open(), and not on resume() where it logically
944 * would be equally necessary. So we define open() as the only
945 * driver <-> device "syncronization point". Should we happen
946 * to lose a notification after open(), then syncronization
947 * will be lost until release()
949 * The hack should not be enabled for CDC WDM devices
950 * conforming to the CDC-WMC r1.1 specification. This is
951 * ensured by setting drain_on_open to false in wdm_probe().
954 set_bit(WDM_DRAIN_ON_OPEN, &desc->flags);
956 spin_lock(&wdm_device_list_lock);
957 list_add(&desc->device_list, &wdm_device_list);
958 spin_unlock(&wdm_device_list_lock);
960 rv = usb_register_dev(intf, &wdm_class);
964 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
968 spin_lock(&wdm_device_list_lock);
969 list_del(&desc->device_list);
970 spin_unlock(&wdm_device_list_lock);
975 static int wdm_manage_power(struct usb_interface *intf, int on)
977 /* need autopm_get/put here to ensure the usbcore sees the new value */
978 int rv = usb_autopm_get_interface(intf);
980 intf->needs_remote_wakeup = on;
982 usb_autopm_put_interface(intf);
986 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
989 struct usb_host_interface *iface;
990 struct usb_endpoint_descriptor *ep;
991 struct usb_cdc_parsed_header hdr;
992 u8 *buffer = intf->altsetting->extra;
993 int buflen = intf->altsetting->extralen;
994 u16 maxcom = WDM_DEFAULT_BUFSIZE;
999 cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
1001 if (hdr.usb_cdc_dmm_desc)
1002 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
1004 iface = intf->cur_altsetting;
1005 if (iface->desc.bNumEndpoints != 1)
1007 ep = &iface->endpoint[0].desc;
1009 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power, false);
1016 * usb_cdc_wdm_register - register a WDM subdriver
1017 * @intf: usb interface the subdriver will associate with
1018 * @ep: interrupt endpoint to monitor for notifications
1019 * @bufsize: maximum message size to support for read/write
1021 * Create WDM usb class character device and associate it with intf
1022 * without binding, allowing another driver to manage the interface.
1024 * The subdriver will manage the given interrupt endpoint exclusively
1025 * and will issue control requests referring to the given intf. It
1026 * will otherwise avoid interferring, and in particular not do
1027 * usb_set_intfdata/usb_get_intfdata on intf.
1029 * The return value is a pointer to the subdriver's struct usb_driver.
1030 * The registering driver is responsible for calling this subdriver's
1031 * disconnect, suspend, resume, pre_reset and post_reset methods from
1034 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
1035 struct usb_endpoint_descriptor *ep,
1037 int (*manage_power)(struct usb_interface *, int))
1041 rv = wdm_create(intf, ep, bufsize, manage_power, true);
1049 EXPORT_SYMBOL(usb_cdc_wdm_register);
1051 static void wdm_disconnect(struct usb_interface *intf)
1053 struct wdm_device *desc;
1054 unsigned long flags;
1056 usb_deregister_dev(intf, &wdm_class);
1057 desc = wdm_find_device(intf);
1058 mutex_lock(&wdm_mutex);
1060 /* the spinlock makes sure no new urbs are generated in the callbacks */
1061 spin_lock_irqsave(&desc->iuspin, flags);
1062 set_bit(WDM_DISCONNECTING, &desc->flags);
1063 set_bit(WDM_READ, &desc->flags);
1064 /* to terminate pending flushes */
1065 clear_bit(WDM_IN_USE, &desc->flags);
1066 spin_unlock_irqrestore(&desc->iuspin, flags);
1067 wake_up_all(&desc->wait);
1068 mutex_lock(&desc->rlock);
1069 mutex_lock(&desc->wlock);
1071 cancel_work_sync(&desc->rxwork);
1072 mutex_unlock(&desc->wlock);
1073 mutex_unlock(&desc->rlock);
1075 /* the desc->intf pointer used as list key is now invalid */
1076 spin_lock(&wdm_device_list_lock);
1077 list_del(&desc->device_list);
1078 spin_unlock(&wdm_device_list_lock);
1083 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1084 mutex_unlock(&wdm_mutex);
1088 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1090 struct wdm_device *desc = wdm_find_device(intf);
1093 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1095 /* if this is an autosuspend the caller does the locking */
1096 if (!PMSG_IS_AUTO(message)) {
1097 mutex_lock(&desc->rlock);
1098 mutex_lock(&desc->wlock);
1100 spin_lock_irq(&desc->iuspin);
1102 if (PMSG_IS_AUTO(message) &&
1103 (test_bit(WDM_IN_USE, &desc->flags)
1104 || test_bit(WDM_RESPONDING, &desc->flags))) {
1105 spin_unlock_irq(&desc->iuspin);
1109 set_bit(WDM_SUSPENDING, &desc->flags);
1110 spin_unlock_irq(&desc->iuspin);
1111 /* callback submits work - order is essential */
1113 cancel_work_sync(&desc->rxwork);
1115 if (!PMSG_IS_AUTO(message)) {
1116 mutex_unlock(&desc->wlock);
1117 mutex_unlock(&desc->rlock);
1124 static int recover_from_urb_loss(struct wdm_device *desc)
1129 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1131 dev_err(&desc->intf->dev,
1132 "Error resume submitting int urb - %d\n", rv);
1138 static int wdm_resume(struct usb_interface *intf)
1140 struct wdm_device *desc = wdm_find_device(intf);
1143 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1145 clear_bit(WDM_SUSPENDING, &desc->flags);
1146 rv = recover_from_urb_loss(desc);
1152 static int wdm_pre_reset(struct usb_interface *intf)
1154 struct wdm_device *desc = wdm_find_device(intf);
1157 * we notify everybody using poll of
1158 * an exceptional situation
1159 * must be done before recovery lest a spontaneous
1160 * message from the device is lost
1162 spin_lock_irq(&desc->iuspin);
1163 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1164 set_bit(WDM_READ, &desc->flags); /* unblock read */
1165 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1166 desc->rerr = -EINTR;
1167 spin_unlock_irq(&desc->iuspin);
1168 wake_up_all(&desc->wait);
1169 mutex_lock(&desc->rlock);
1170 mutex_lock(&desc->wlock);
1172 cancel_work_sync(&desc->rxwork);
1176 static int wdm_post_reset(struct usb_interface *intf)
1178 struct wdm_device *desc = wdm_find_device(intf);
1181 clear_bit(WDM_OVERFLOW, &desc->flags);
1182 clear_bit(WDM_RESETTING, &desc->flags);
1183 rv = recover_from_urb_loss(desc);
1184 mutex_unlock(&desc->wlock);
1185 mutex_unlock(&desc->rlock);
1189 static struct usb_driver wdm_driver = {
1192 .disconnect = wdm_disconnect,
1194 .suspend = wdm_suspend,
1195 .resume = wdm_resume,
1196 .reset_resume = wdm_resume,
1198 .pre_reset = wdm_pre_reset,
1199 .post_reset = wdm_post_reset,
1200 .id_table = wdm_ids,
1201 .supports_autosuspend = 1,
1202 .disable_hub_initiated_lpm = 1,
1205 module_usb_driver(wdm_driver);
1207 MODULE_AUTHOR(DRIVER_AUTHOR);
1208 MODULE_DESCRIPTION(DRIVER_DESC);
1209 MODULE_LICENSE("GPL");