1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * message.c - synchronous message handling
4   *
5   * Released under the GPLv2 only.
6   */
7  
8  #include <linux/acpi.h>
9  #include <linux/pci.h>	/* for scatterlist macros */
10  #include <linux/usb.h>
11  #include <linux/module.h>
12  #include <linux/of.h>
13  #include <linux/slab.h>
14  #include <linux/mm.h>
15  #include <linux/timer.h>
16  #include <linux/ctype.h>
17  #include <linux/nls.h>
18  #include <linux/device.h>
19  #include <linux/scatterlist.h>
20  #include <linux/usb/cdc.h>
21  #include <linux/usb/quirks.h>
22  #include <linux/usb/hcd.h>	/* for usbcore internals */
23  #include <linux/usb/of.h>
24  #include <asm/byteorder.h>
25  
26  #include "usb.h"
27  
28  static void cancel_async_set_config(struct usb_device *udev);
29  
30  struct api_context {
31  	struct completion	done;
32  	int			status;
33  };
34  
usb_api_blocking_completion(struct urb * urb)35  static void usb_api_blocking_completion(struct urb *urb)
36  {
37  	struct api_context *ctx = urb->context;
38  
39  	ctx->status = urb->status;
40  	complete(&ctx->done);
41  }
42  
43  
44  /*
45   * Starts urb and waits for completion or timeout. Note that this call
46   * is NOT interruptible. Many device driver i/o requests should be
47   * interruptible and therefore these drivers should implement their
48   * own interruptible routines.
49   */
usb_start_wait_urb(struct urb * urb,int timeout,int * actual_length)50  static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
51  {
52  	struct api_context ctx;
53  	unsigned long expire;
54  	int retval;
55  
56  	init_completion(&ctx.done);
57  	urb->context = &ctx;
58  	urb->actual_length = 0;
59  	retval = usb_submit_urb(urb, GFP_NOIO);
60  	if (unlikely(retval))
61  		goto out;
62  
63  	expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
64  	if (!wait_for_completion_timeout(&ctx.done, expire)) {
65  		usb_kill_urb(urb);
66  		retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
67  
68  		dev_dbg(&urb->dev->dev,
69  			"%s timed out on ep%d%s len=%u/%u\n",
70  			current->comm,
71  			usb_endpoint_num(&urb->ep->desc),
72  			usb_urb_dir_in(urb) ? "in" : "out",
73  			urb->actual_length,
74  			urb->transfer_buffer_length);
75  	} else
76  		retval = ctx.status;
77  out:
78  	if (actual_length)
79  		*actual_length = urb->actual_length;
80  
81  	usb_free_urb(urb);
82  	return retval;
83  }
84  
85  /*-------------------------------------------------------------------*/
86  /* returns status (negative) or length (positive) */
usb_internal_control_msg(struct usb_device * usb_dev,unsigned int pipe,struct usb_ctrlrequest * cmd,void * data,int len,int timeout)87  static int usb_internal_control_msg(struct usb_device *usb_dev,
88  				    unsigned int pipe,
89  				    struct usb_ctrlrequest *cmd,
90  				    void *data, int len, int timeout)
91  {
92  	struct urb *urb;
93  	int retv;
94  	int length;
95  
96  	urb = usb_alloc_urb(0, GFP_NOIO);
97  	if (!urb)
98  		return -ENOMEM;
99  
100  	usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
101  			     len, usb_api_blocking_completion, NULL);
102  
103  	retv = usb_start_wait_urb(urb, timeout, &length);
104  	if (retv < 0)
105  		return retv;
106  	else
107  		return length;
108  }
109  
110  /**
111   * usb_control_msg - Builds a control urb, sends it off and waits for completion
112   * @dev: pointer to the usb device to send the message to
113   * @pipe: endpoint "pipe" to send the message to
114   * @request: USB message request value
115   * @requesttype: USB message request type value
116   * @value: USB message value
117   * @index: USB message index value
118   * @data: pointer to the data to send
119   * @size: length in bytes of the data to send
120   * @timeout: time in msecs to wait for the message to complete before timing
121   *	out (if 0 the wait is forever)
122   *
123   * Context: task context, might sleep.
124   *
125   * This function sends a simple control message to a specified endpoint and
126   * waits for the message to complete, or timeout.
127   *
128   * Don't use this function from within an interrupt context. If you need
129   * an asynchronous message, or need to send a message from within interrupt
130   * context, use usb_submit_urb(). If a thread in your driver uses this call,
131   * make sure your disconnect() method can wait for it to complete. Since you
132   * don't have a handle on the URB used, you can't cancel the request.
133   *
134   * Return: If successful, the number of bytes transferred. Otherwise, a negative
135   * error number.
136   */
usb_control_msg(struct usb_device * dev,unsigned int pipe,__u8 request,__u8 requesttype,__u16 value,__u16 index,void * data,__u16 size,int timeout)137  int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
138  		    __u8 requesttype, __u16 value, __u16 index, void *data,
139  		    __u16 size, int timeout)
140  {
141  	struct usb_ctrlrequest *dr;
142  	int ret;
143  
144  	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
145  	if (!dr)
146  		return -ENOMEM;
147  
148  	dr->bRequestType = requesttype;
149  	dr->bRequest = request;
150  	dr->wValue = cpu_to_le16(value);
151  	dr->wIndex = cpu_to_le16(index);
152  	dr->wLength = cpu_to_le16(size);
153  
154  	ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout);
155  
156  	/* Linger a bit, prior to the next control message. */
157  	if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG)
158  		msleep(200);
159  
160  	kfree(dr);
161  
162  	return ret;
163  }
164  EXPORT_SYMBOL_GPL(usb_control_msg);
165  
166  /**
167   * usb_control_msg_send - Builds a control "send" message, sends it off and waits for completion
168   * @dev: pointer to the usb device to send the message to
169   * @endpoint: endpoint to send the message to
170   * @request: USB message request value
171   * @requesttype: USB message request type value
172   * @value: USB message value
173   * @index: USB message index value
174   * @driver_data: pointer to the data to send
175   * @size: length in bytes of the data to send
176   * @timeout: time in msecs to wait for the message to complete before timing
177   *	out (if 0 the wait is forever)
178   * @memflags: the flags for memory allocation for buffers
179   *
180   * Context: !in_interrupt ()
181   *
182   * This function sends a control message to a specified endpoint that is not
183   * expected to fill in a response (i.e. a "send message") and waits for the
184   * message to complete, or timeout.
185   *
186   * Do not use this function from within an interrupt context. If you need
187   * an asynchronous message, or need to send a message from within interrupt
188   * context, use usb_submit_urb(). If a thread in your driver uses this call,
189   * make sure your disconnect() method can wait for it to complete. Since you
190   * don't have a handle on the URB used, you can't cancel the request.
191   *
192   * The data pointer can be made to a reference on the stack, or anywhere else,
193   * as it will not be modified at all.  This does not have the restriction that
194   * usb_control_msg() has where the data pointer must be to dynamically allocated
195   * memory (i.e. memory that can be successfully DMAed to a device).
196   *
197   * Return: If successful, 0 is returned, Otherwise, a negative error number.
198   */
usb_control_msg_send(struct usb_device * dev,__u8 endpoint,__u8 request,__u8 requesttype,__u16 value,__u16 index,const void * driver_data,__u16 size,int timeout,gfp_t memflags)199  int usb_control_msg_send(struct usb_device *dev, __u8 endpoint, __u8 request,
200  			 __u8 requesttype, __u16 value, __u16 index,
201  			 const void *driver_data, __u16 size, int timeout,
202  			 gfp_t memflags)
203  {
204  	unsigned int pipe = usb_sndctrlpipe(dev, endpoint);
205  	int ret;
206  	u8 *data = NULL;
207  
208  	if (size) {
209  		data = kmemdup(driver_data, size, memflags);
210  		if (!data)
211  			return -ENOMEM;
212  	}
213  
214  	ret = usb_control_msg(dev, pipe, request, requesttype, value, index,
215  			      data, size, timeout);
216  	kfree(data);
217  
218  	if (ret < 0)
219  		return ret;
220  
221  	return 0;
222  }
223  EXPORT_SYMBOL_GPL(usb_control_msg_send);
224  
225  /**
226   * usb_control_msg_recv - Builds a control "receive" message, sends it off and waits for completion
227   * @dev: pointer to the usb device to send the message to
228   * @endpoint: endpoint to send the message to
229   * @request: USB message request value
230   * @requesttype: USB message request type value
231   * @value: USB message value
232   * @index: USB message index value
233   * @driver_data: pointer to the data to be filled in by the message
234   * @size: length in bytes of the data to be received
235   * @timeout: time in msecs to wait for the message to complete before timing
236   *	out (if 0 the wait is forever)
237   * @memflags: the flags for memory allocation for buffers
238   *
239   * Context: !in_interrupt ()
240   *
241   * This function sends a control message to a specified endpoint that is
242   * expected to fill in a response (i.e. a "receive message") and waits for the
243   * message to complete, or timeout.
244   *
245   * Do not use this function from within an interrupt context. If you need
246   * an asynchronous message, or need to send a message from within interrupt
247   * context, use usb_submit_urb(). If a thread in your driver uses this call,
248   * make sure your disconnect() method can wait for it to complete. Since you
249   * don't have a handle on the URB used, you can't cancel the request.
250   *
251   * The data pointer can be made to a reference on the stack, or anywhere else
252   * that can be successfully written to.  This function does not have the
253   * restriction that usb_control_msg() has where the data pointer must be to
254   * dynamically allocated memory (i.e. memory that can be successfully DMAed to a
255   * device).
256   *
257   * The "whole" message must be properly received from the device in order for
258   * this function to be successful.  If a device returns less than the expected
259   * amount of data, then the function will fail.  Do not use this for messages
260   * where a variable amount of data might be returned.
261   *
262   * Return: If successful, 0 is returned, Otherwise, a negative error number.
263   */
usb_control_msg_recv(struct usb_device * dev,__u8 endpoint,__u8 request,__u8 requesttype,__u16 value,__u16 index,void * driver_data,__u16 size,int timeout,gfp_t memflags)264  int usb_control_msg_recv(struct usb_device *dev, __u8 endpoint, __u8 request,
265  			 __u8 requesttype, __u16 value, __u16 index,
266  			 void *driver_data, __u16 size, int timeout,
267  			 gfp_t memflags)
268  {
269  	unsigned int pipe = usb_rcvctrlpipe(dev, endpoint);
270  	int ret;
271  	u8 *data;
272  
273  	if (!size || !driver_data)
274  		return -EINVAL;
275  
276  	data = kmalloc(size, memflags);
277  	if (!data)
278  		return -ENOMEM;
279  
280  	ret = usb_control_msg(dev, pipe, request, requesttype, value, index,
281  			      data, size, timeout);
282  
283  	if (ret < 0)
284  		goto exit;
285  
286  	if (ret == size) {
287  		memcpy(driver_data, data, size);
288  		ret = 0;
289  	} else {
290  		ret = -EREMOTEIO;
291  	}
292  
293  exit:
294  	kfree(data);
295  	return ret;
296  }
297  EXPORT_SYMBOL_GPL(usb_control_msg_recv);
298  
299  /**
300   * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
301   * @usb_dev: pointer to the usb device to send the message to
302   * @pipe: endpoint "pipe" to send the message to
303   * @data: pointer to the data to send
304   * @len: length in bytes of the data to send
305   * @actual_length: pointer to a location to put the actual length transferred
306   *	in bytes
307   * @timeout: time in msecs to wait for the message to complete before
308   *	timing out (if 0 the wait is forever)
309   *
310   * Context: task context, might sleep.
311   *
312   * This function sends a simple interrupt message to a specified endpoint and
313   * waits for the message to complete, or timeout.
314   *
315   * Don't use this function from within an interrupt context. If you need
316   * an asynchronous message, or need to send a message from within interrupt
317   * context, use usb_submit_urb() If a thread in your driver uses this call,
318   * make sure your disconnect() method can wait for it to complete. Since you
319   * don't have a handle on the URB used, you can't cancel the request.
320   *
321   * Return:
322   * If successful, 0. Otherwise a negative error number. The number of actual
323   * bytes transferred will be stored in the @actual_length parameter.
324   */
usb_interrupt_msg(struct usb_device * usb_dev,unsigned int pipe,void * data,int len,int * actual_length,int timeout)325  int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
326  		      void *data, int len, int *actual_length, int timeout)
327  {
328  	return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
329  }
330  EXPORT_SYMBOL_GPL(usb_interrupt_msg);
331  
332  /**
333   * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
334   * @usb_dev: pointer to the usb device to send the message to
335   * @pipe: endpoint "pipe" to send the message to
336   * @data: pointer to the data to send
337   * @len: length in bytes of the data to send
338   * @actual_length: pointer to a location to put the actual length transferred
339   *	in bytes
340   * @timeout: time in msecs to wait for the message to complete before
341   *	timing out (if 0 the wait is forever)
342   *
343   * Context: task context, might sleep.
344   *
345   * This function sends a simple bulk message to a specified endpoint
346   * and waits for the message to complete, or timeout.
347   *
348   * Don't use this function from within an interrupt context. If you need
349   * an asynchronous message, or need to send a message from within interrupt
350   * context, use usb_submit_urb() If a thread in your driver uses this call,
351   * make sure your disconnect() method can wait for it to complete. Since you
352   * don't have a handle on the URB used, you can't cancel the request.
353   *
354   * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
355   * users are forced to abuse this routine by using it to submit URBs for
356   * interrupt endpoints.  We will take the liberty of creating an interrupt URB
357   * (with the default interval) if the target is an interrupt endpoint.
358   *
359   * Return:
360   * If successful, 0. Otherwise a negative error number. The number of actual
361   * bytes transferred will be stored in the @actual_length parameter.
362   *
363   */
usb_bulk_msg(struct usb_device * usb_dev,unsigned int pipe,void * data,int len,int * actual_length,int timeout)364  int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
365  		 void *data, int len, int *actual_length, int timeout)
366  {
367  	struct urb *urb;
368  	struct usb_host_endpoint *ep;
369  
370  	ep = usb_pipe_endpoint(usb_dev, pipe);
371  	if (!ep || len < 0)
372  		return -EINVAL;
373  
374  	urb = usb_alloc_urb(0, GFP_KERNEL);
375  	if (!urb)
376  		return -ENOMEM;
377  
378  	if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
379  			USB_ENDPOINT_XFER_INT) {
380  		pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
381  		usb_fill_int_urb(urb, usb_dev, pipe, data, len,
382  				usb_api_blocking_completion, NULL,
383  				ep->desc.bInterval);
384  	} else
385  		usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
386  				usb_api_blocking_completion, NULL);
387  
388  	return usb_start_wait_urb(urb, timeout, actual_length);
389  }
390  EXPORT_SYMBOL_GPL(usb_bulk_msg);
391  
392  /*-------------------------------------------------------------------*/
393  
sg_clean(struct usb_sg_request * io)394  static void sg_clean(struct usb_sg_request *io)
395  {
396  	if (io->urbs) {
397  		while (io->entries--)
398  			usb_free_urb(io->urbs[io->entries]);
399  		kfree(io->urbs);
400  		io->urbs = NULL;
401  	}
402  	io->dev = NULL;
403  }
404  
sg_complete(struct urb * urb)405  static void sg_complete(struct urb *urb)
406  {
407  	unsigned long flags;
408  	struct usb_sg_request *io = urb->context;
409  	int status = urb->status;
410  
411  	spin_lock_irqsave(&io->lock, flags);
412  
413  	/* In 2.5 we require hcds' endpoint queues not to progress after fault
414  	 * reports, until the completion callback (this!) returns.  That lets
415  	 * device driver code (like this routine) unlink queued urbs first,
416  	 * if it needs to, since the HC won't work on them at all.  So it's
417  	 * not possible for page N+1 to overwrite page N, and so on.
418  	 *
419  	 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
420  	 * complete before the HCD can get requests away from hardware,
421  	 * though never during cleanup after a hard fault.
422  	 */
423  	if (io->status
424  			&& (io->status != -ECONNRESET
425  				|| status != -ECONNRESET)
426  			&& urb->actual_length) {
427  		dev_err(io->dev->bus->controller,
428  			"dev %s ep%d%s scatterlist error %d/%d\n",
429  			io->dev->devpath,
430  			usb_endpoint_num(&urb->ep->desc),
431  			usb_urb_dir_in(urb) ? "in" : "out",
432  			status, io->status);
433  		/* BUG (); */
434  	}
435  
436  	if (io->status == 0 && status && status != -ECONNRESET) {
437  		int i, found, retval;
438  
439  		io->status = status;
440  
441  		/* the previous urbs, and this one, completed already.
442  		 * unlink pending urbs so they won't rx/tx bad data.
443  		 * careful: unlink can sometimes be synchronous...
444  		 */
445  		spin_unlock_irqrestore(&io->lock, flags);
446  		for (i = 0, found = 0; i < io->entries; i++) {
447  			if (!io->urbs[i])
448  				continue;
449  			if (found) {
450  				usb_block_urb(io->urbs[i]);
451  				retval = usb_unlink_urb(io->urbs[i]);
452  				if (retval != -EINPROGRESS &&
453  				    retval != -ENODEV &&
454  				    retval != -EBUSY &&
455  				    retval != -EIDRM)
456  					dev_err(&io->dev->dev,
457  						"%s, unlink --> %d\n",
458  						__func__, retval);
459  			} else if (urb == io->urbs[i])
460  				found = 1;
461  		}
462  		spin_lock_irqsave(&io->lock, flags);
463  	}
464  
465  	/* on the last completion, signal usb_sg_wait() */
466  	io->bytes += urb->actual_length;
467  	io->count--;
468  	if (!io->count)
469  		complete(&io->complete);
470  
471  	spin_unlock_irqrestore(&io->lock, flags);
472  }
473  
474  
475  /**
476   * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
477   * @io: request block being initialized.  until usb_sg_wait() returns,
478   *	treat this as a pointer to an opaque block of memory,
479   * @dev: the usb device that will send or receive the data
480   * @pipe: endpoint "pipe" used to transfer the data
481   * @period: polling rate for interrupt endpoints, in frames or
482   * 	(for high speed endpoints) microframes; ignored for bulk
483   * @sg: scatterlist entries
484   * @nents: how many entries in the scatterlist
485   * @length: how many bytes to send from the scatterlist, or zero to
486   * 	send every byte identified in the list.
487   * @mem_flags: SLAB_* flags affecting memory allocations in this call
488   *
489   * This initializes a scatter/gather request, allocating resources such as
490   * I/O mappings and urb memory (except maybe memory used by USB controller
491   * drivers).
492   *
493   * The request must be issued using usb_sg_wait(), which waits for the I/O to
494   * complete (or to be canceled) and then cleans up all resources allocated by
495   * usb_sg_init().
496   *
497   * The request may be canceled with usb_sg_cancel(), either before or after
498   * usb_sg_wait() is called.
499   *
500   * Return: Zero for success, else a negative errno value.
501   */
usb_sg_init(struct usb_sg_request * io,struct usb_device * dev,unsigned pipe,unsigned period,struct scatterlist * sg,int nents,size_t length,gfp_t mem_flags)502  int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
503  		unsigned pipe, unsigned	period, struct scatterlist *sg,
504  		int nents, size_t length, gfp_t mem_flags)
505  {
506  	int i;
507  	int urb_flags;
508  	int use_sg;
509  
510  	if (!io || !dev || !sg
511  			|| usb_pipecontrol(pipe)
512  			|| usb_pipeisoc(pipe)
513  			|| nents <= 0)
514  		return -EINVAL;
515  
516  	spin_lock_init(&io->lock);
517  	io->dev = dev;
518  	io->pipe = pipe;
519  
520  	if (dev->bus->sg_tablesize > 0) {
521  		use_sg = true;
522  		io->entries = 1;
523  	} else {
524  		use_sg = false;
525  		io->entries = nents;
526  	}
527  
528  	/* initialize all the urbs we'll use */
529  	io->urbs = kmalloc_array(io->entries, sizeof(*io->urbs), mem_flags);
530  	if (!io->urbs)
531  		goto nomem;
532  
533  	urb_flags = URB_NO_INTERRUPT;
534  	if (usb_pipein(pipe))
535  		urb_flags |= URB_SHORT_NOT_OK;
536  
537  	for_each_sg(sg, sg, io->entries, i) {
538  		struct urb *urb;
539  		unsigned len;
540  
541  		urb = usb_alloc_urb(0, mem_flags);
542  		if (!urb) {
543  			io->entries = i;
544  			goto nomem;
545  		}
546  		io->urbs[i] = urb;
547  
548  		urb->dev = NULL;
549  		urb->pipe = pipe;
550  		urb->interval = period;
551  		urb->transfer_flags = urb_flags;
552  		urb->complete = sg_complete;
553  		urb->context = io;
554  		urb->sg = sg;
555  
556  		if (use_sg) {
557  			/* There is no single transfer buffer */
558  			urb->transfer_buffer = NULL;
559  			urb->num_sgs = nents;
560  
561  			/* A length of zero means transfer the whole sg list */
562  			len = length;
563  			if (len == 0) {
564  				struct scatterlist	*sg2;
565  				int			j;
566  
567  				for_each_sg(sg, sg2, nents, j)
568  					len += sg2->length;
569  			}
570  		} else {
571  			/*
572  			 * Some systems can't use DMA; they use PIO instead.
573  			 * For their sakes, transfer_buffer is set whenever
574  			 * possible.
575  			 */
576  			if (!PageHighMem(sg_page(sg)))
577  				urb->transfer_buffer = sg_virt(sg);
578  			else
579  				urb->transfer_buffer = NULL;
580  
581  			len = sg->length;
582  			if (length) {
583  				len = min_t(size_t, len, length);
584  				length -= len;
585  				if (length == 0)
586  					io->entries = i + 1;
587  			}
588  		}
589  		urb->transfer_buffer_length = len;
590  	}
591  	io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
592  
593  	/* transaction state */
594  	io->count = io->entries;
595  	io->status = 0;
596  	io->bytes = 0;
597  	init_completion(&io->complete);
598  	return 0;
599  
600  nomem:
601  	sg_clean(io);
602  	return -ENOMEM;
603  }
604  EXPORT_SYMBOL_GPL(usb_sg_init);
605  
606  /**
607   * usb_sg_wait - synchronously execute scatter/gather request
608   * @io: request block handle, as initialized with usb_sg_init().
609   * 	some fields become accessible when this call returns.
610   *
611   * Context: task context, might sleep.
612   *
613   * This function blocks until the specified I/O operation completes.  It
614   * leverages the grouping of the related I/O requests to get good transfer
615   * rates, by queueing the requests.  At higher speeds, such queuing can
616   * significantly improve USB throughput.
617   *
618   * There are three kinds of completion for this function.
619   *
620   * (1) success, where io->status is zero.  The number of io->bytes
621   *     transferred is as requested.
622   * (2) error, where io->status is a negative errno value.  The number
623   *     of io->bytes transferred before the error is usually less
624   *     than requested, and can be nonzero.
625   * (3) cancellation, a type of error with status -ECONNRESET that
626   *     is initiated by usb_sg_cancel().
627   *
628   * When this function returns, all memory allocated through usb_sg_init() or
629   * this call will have been freed.  The request block parameter may still be
630   * passed to usb_sg_cancel(), or it may be freed.  It could also be
631   * reinitialized and then reused.
632   *
633   * Data Transfer Rates:
634   *
635   * Bulk transfers are valid for full or high speed endpoints.
636   * The best full speed data rate is 19 packets of 64 bytes each
637   * per frame, or 1216 bytes per millisecond.
638   * The best high speed data rate is 13 packets of 512 bytes each
639   * per microframe, or 52 KBytes per millisecond.
640   *
641   * The reason to use interrupt transfers through this API would most likely
642   * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
643   * could be transferred.  That capability is less useful for low or full
644   * speed interrupt endpoints, which allow at most one packet per millisecond,
645   * of at most 8 or 64 bytes (respectively).
646   *
647   * It is not necessary to call this function to reserve bandwidth for devices
648   * under an xHCI host controller, as the bandwidth is reserved when the
649   * configuration or interface alt setting is selected.
650   */
usb_sg_wait(struct usb_sg_request * io)651  void usb_sg_wait(struct usb_sg_request *io)
652  {
653  	int i;
654  	int entries = io->entries;
655  
656  	/* queue the urbs.  */
657  	spin_lock_irq(&io->lock);
658  	i = 0;
659  	while (i < entries && !io->status) {
660  		int retval;
661  
662  		io->urbs[i]->dev = io->dev;
663  		spin_unlock_irq(&io->lock);
664  
665  		retval = usb_submit_urb(io->urbs[i], GFP_NOIO);
666  
667  		switch (retval) {
668  			/* maybe we retrying will recover */
669  		case -ENXIO:	/* hc didn't queue this one */
670  		case -EAGAIN:
671  		case -ENOMEM:
672  			retval = 0;
673  			yield();
674  			break;
675  
676  			/* no error? continue immediately.
677  			 *
678  			 * NOTE: to work better with UHCI (4K I/O buffer may
679  			 * need 3K of TDs) it may be good to limit how many
680  			 * URBs are queued at once; N milliseconds?
681  			 */
682  		case 0:
683  			++i;
684  			cpu_relax();
685  			break;
686  
687  			/* fail any uncompleted urbs */
688  		default:
689  			io->urbs[i]->status = retval;
690  			dev_dbg(&io->dev->dev, "%s, submit --> %d\n",
691  				__func__, retval);
692  			usb_sg_cancel(io);
693  		}
694  		spin_lock_irq(&io->lock);
695  		if (retval && (io->status == 0 || io->status == -ECONNRESET))
696  			io->status = retval;
697  	}
698  	io->count -= entries - i;
699  	if (io->count == 0)
700  		complete(&io->complete);
701  	spin_unlock_irq(&io->lock);
702  
703  	/* OK, yes, this could be packaged as non-blocking.
704  	 * So could the submit loop above ... but it's easier to
705  	 * solve neither problem than to solve both!
706  	 */
707  	wait_for_completion(&io->complete);
708  
709  	sg_clean(io);
710  }
711  EXPORT_SYMBOL_GPL(usb_sg_wait);
712  
713  /**
714   * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
715   * @io: request block, initialized with usb_sg_init()
716   *
717   * This stops a request after it has been started by usb_sg_wait().
718   * It can also prevents one initialized by usb_sg_init() from starting,
719   * so that call just frees resources allocated to the request.
720   */
usb_sg_cancel(struct usb_sg_request * io)721  void usb_sg_cancel(struct usb_sg_request *io)
722  {
723  	unsigned long flags;
724  	int i, retval;
725  
726  	spin_lock_irqsave(&io->lock, flags);
727  	if (io->status || io->count == 0) {
728  		spin_unlock_irqrestore(&io->lock, flags);
729  		return;
730  	}
731  	/* shut everything down */
732  	io->status = -ECONNRESET;
733  	io->count++;		/* Keep the request alive until we're done */
734  	spin_unlock_irqrestore(&io->lock, flags);
735  
736  	for (i = io->entries - 1; i >= 0; --i) {
737  		usb_block_urb(io->urbs[i]);
738  
739  		retval = usb_unlink_urb(io->urbs[i]);
740  		if (retval != -EINPROGRESS
741  		    && retval != -ENODEV
742  		    && retval != -EBUSY
743  		    && retval != -EIDRM)
744  			dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
745  				 __func__, retval);
746  	}
747  
748  	spin_lock_irqsave(&io->lock, flags);
749  	io->count--;
750  	if (!io->count)
751  		complete(&io->complete);
752  	spin_unlock_irqrestore(&io->lock, flags);
753  }
754  EXPORT_SYMBOL_GPL(usb_sg_cancel);
755  
756  /*-------------------------------------------------------------------*/
757  
758  /**
759   * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
760   * @dev: the device whose descriptor is being retrieved
761   * @type: the descriptor type (USB_DT_*)
762   * @index: the number of the descriptor
763   * @buf: where to put the descriptor
764   * @size: how big is "buf"?
765   *
766   * Context: task context, might sleep.
767   *
768   * Gets a USB descriptor.  Convenience functions exist to simplify
769   * getting some types of descriptors.  Use
770   * usb_get_string() or usb_string() for USB_DT_STRING.
771   * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
772   * are part of the device structure.
773   * In addition to a number of USB-standard descriptors, some
774   * devices also use class-specific or vendor-specific descriptors.
775   *
776   * This call is synchronous, and may not be used in an interrupt context.
777   *
778   * Return: The number of bytes received on success, or else the status code
779   * returned by the underlying usb_control_msg() call.
780   */
usb_get_descriptor(struct usb_device * dev,unsigned char type,unsigned char index,void * buf,int size)781  int usb_get_descriptor(struct usb_device *dev, unsigned char type,
782  		       unsigned char index, void *buf, int size)
783  {
784  	int i;
785  	int result;
786  
787  	if (size <= 0)		/* No point in asking for no data */
788  		return -EINVAL;
789  
790  	memset(buf, 0, size);	/* Make sure we parse really received data */
791  
792  	for (i = 0; i < 3; ++i) {
793  		/* retry on length 0 or error; some devices are flakey */
794  		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
795  				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
796  				(type << 8) + index, 0, buf, size,
797  				USB_CTRL_GET_TIMEOUT);
798  		if (result <= 0 && result != -ETIMEDOUT)
799  			continue;
800  		if (result > 1 && ((u8 *)buf)[1] != type) {
801  			result = -ENODATA;
802  			continue;
803  		}
804  		break;
805  	}
806  	return result;
807  }
808  EXPORT_SYMBOL_GPL(usb_get_descriptor);
809  
810  /**
811   * usb_get_string - gets a string descriptor
812   * @dev: the device whose string descriptor is being retrieved
813   * @langid: code for language chosen (from string descriptor zero)
814   * @index: the number of the descriptor
815   * @buf: where to put the string
816   * @size: how big is "buf"?
817   *
818   * Context: task context, might sleep.
819   *
820   * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
821   * in little-endian byte order).
822   * The usb_string() function will often be a convenient way to turn
823   * these strings into kernel-printable form.
824   *
825   * Strings may be referenced in device, configuration, interface, or other
826   * descriptors, and could also be used in vendor-specific ways.
827   *
828   * This call is synchronous, and may not be used in an interrupt context.
829   *
830   * Return: The number of bytes received on success, or else the status code
831   * returned by the underlying usb_control_msg() call.
832   */
usb_get_string(struct usb_device * dev,unsigned short langid,unsigned char index,void * buf,int size)833  static int usb_get_string(struct usb_device *dev, unsigned short langid,
834  			  unsigned char index, void *buf, int size)
835  {
836  	int i;
837  	int result;
838  
839  	if (size <= 0)		/* No point in asking for no data */
840  		return -EINVAL;
841  
842  	for (i = 0; i < 3; ++i) {
843  		/* retry on length 0 or stall; some devices are flakey */
844  		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
845  			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
846  			(USB_DT_STRING << 8) + index, langid, buf, size,
847  			USB_CTRL_GET_TIMEOUT);
848  		if (result == 0 || result == -EPIPE)
849  			continue;
850  		if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) {
851  			result = -ENODATA;
852  			continue;
853  		}
854  		break;
855  	}
856  	return result;
857  }
858  
usb_try_string_workarounds(unsigned char * buf,int * length)859  static void usb_try_string_workarounds(unsigned char *buf, int *length)
860  {
861  	int newlength, oldlength = *length;
862  
863  	for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
864  		if (!isprint(buf[newlength]) || buf[newlength + 1])
865  			break;
866  
867  	if (newlength > 2) {
868  		buf[0] = newlength;
869  		*length = newlength;
870  	}
871  }
872  
usb_string_sub(struct usb_device * dev,unsigned int langid,unsigned int index,unsigned char * buf)873  static int usb_string_sub(struct usb_device *dev, unsigned int langid,
874  			  unsigned int index, unsigned char *buf)
875  {
876  	int rc;
877  
878  	/* Try to read the string descriptor by asking for the maximum
879  	 * possible number of bytes */
880  	if (dev->quirks & USB_QUIRK_STRING_FETCH_255)
881  		rc = -EIO;
882  	else
883  		rc = usb_get_string(dev, langid, index, buf, 255);
884  
885  	/* If that failed try to read the descriptor length, then
886  	 * ask for just that many bytes */
887  	if (rc < 2) {
888  		rc = usb_get_string(dev, langid, index, buf, 2);
889  		if (rc == 2)
890  			rc = usb_get_string(dev, langid, index, buf, buf[0]);
891  	}
892  
893  	if (rc >= 2) {
894  		if (!buf[0] && !buf[1])
895  			usb_try_string_workarounds(buf, &rc);
896  
897  		/* There might be extra junk at the end of the descriptor */
898  		if (buf[0] < rc)
899  			rc = buf[0];
900  
901  		rc = rc - (rc & 1); /* force a multiple of two */
902  	}
903  
904  	if (rc < 2)
905  		rc = (rc < 0 ? rc : -EINVAL);
906  
907  	return rc;
908  }
909  
usb_get_langid(struct usb_device * dev,unsigned char * tbuf)910  static int usb_get_langid(struct usb_device *dev, unsigned char *tbuf)
911  {
912  	int err;
913  
914  	if (dev->have_langid)
915  		return 0;
916  
917  	if (dev->string_langid < 0)
918  		return -EPIPE;
919  
920  	err = usb_string_sub(dev, 0, 0, tbuf);
921  
922  	/* If the string was reported but is malformed, default to english
923  	 * (0x0409) */
924  	if (err == -ENODATA || (err > 0 && err < 4)) {
925  		dev->string_langid = 0x0409;
926  		dev->have_langid = 1;
927  		dev_err(&dev->dev,
928  			"language id specifier not provided by device, defaulting to English\n");
929  		return 0;
930  	}
931  
932  	/* In case of all other errors, we assume the device is not able to
933  	 * deal with strings at all. Set string_langid to -1 in order to
934  	 * prevent any string to be retrieved from the device */
935  	if (err < 0) {
936  		dev_info(&dev->dev, "string descriptor 0 read error: %d\n",
937  					err);
938  		dev->string_langid = -1;
939  		return -EPIPE;
940  	}
941  
942  	/* always use the first langid listed */
943  	dev->string_langid = tbuf[2] | (tbuf[3] << 8);
944  	dev->have_langid = 1;
945  	dev_dbg(&dev->dev, "default language 0x%04x\n",
946  				dev->string_langid);
947  	return 0;
948  }
949  
950  /**
951   * usb_string - returns UTF-8 version of a string descriptor
952   * @dev: the device whose string descriptor is being retrieved
953   * @index: the number of the descriptor
954   * @buf: where to put the string
955   * @size: how big is "buf"?
956   *
957   * Context: task context, might sleep.
958   *
959   * This converts the UTF-16LE encoded strings returned by devices, from
960   * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
961   * that are more usable in most kernel contexts.  Note that this function
962   * chooses strings in the first language supported by the device.
963   *
964   * This call is synchronous, and may not be used in an interrupt context.
965   *
966   * Return: length of the string (>= 0) or usb_control_msg status (< 0).
967   */
usb_string(struct usb_device * dev,int index,char * buf,size_t size)968  int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
969  {
970  	unsigned char *tbuf;
971  	int err;
972  
973  	if (dev->state == USB_STATE_SUSPENDED)
974  		return -EHOSTUNREACH;
975  	if (size <= 0 || !buf)
976  		return -EINVAL;
977  	buf[0] = 0;
978  	if (index <= 0 || index >= 256)
979  		return -EINVAL;
980  	tbuf = kmalloc(256, GFP_NOIO);
981  	if (!tbuf)
982  		return -ENOMEM;
983  
984  	err = usb_get_langid(dev, tbuf);
985  	if (err < 0)
986  		goto errout;
987  
988  	err = usb_string_sub(dev, dev->string_langid, index, tbuf);
989  	if (err < 0)
990  		goto errout;
991  
992  	size--;		/* leave room for trailing NULL char in output buffer */
993  	err = utf16s_to_utf8s((wchar_t *) &tbuf[2], (err - 2) / 2,
994  			UTF16_LITTLE_ENDIAN, buf, size);
995  	buf[err] = 0;
996  
997  	if (tbuf[1] != USB_DT_STRING)
998  		dev_dbg(&dev->dev,
999  			"wrong descriptor type %02x for string %d (\"%s\")\n",
1000  			tbuf[1], index, buf);
1001  
1002   errout:
1003  	kfree(tbuf);
1004  	return err;
1005  }
1006  EXPORT_SYMBOL_GPL(usb_string);
1007  
1008  /* one UTF-8-encoded 16-bit character has at most three bytes */
1009  #define MAX_USB_STRING_SIZE (127 * 3 + 1)
1010  
1011  /**
1012   * usb_cache_string - read a string descriptor and cache it for later use
1013   * @udev: the device whose string descriptor is being read
1014   * @index: the descriptor index
1015   *
1016   * Return: A pointer to a kmalloc'ed buffer containing the descriptor string,
1017   * or %NULL if the index is 0 or the string could not be read.
1018   */
usb_cache_string(struct usb_device * udev,int index)1019  char *usb_cache_string(struct usb_device *udev, int index)
1020  {
1021  	char *buf;
1022  	char *smallbuf = NULL;
1023  	int len;
1024  
1025  	if (index <= 0)
1026  		return NULL;
1027  
1028  	buf = kmalloc(MAX_USB_STRING_SIZE, GFP_NOIO);
1029  	if (buf) {
1030  		len = usb_string(udev, index, buf, MAX_USB_STRING_SIZE);
1031  		if (len > 0) {
1032  			smallbuf = kmalloc(++len, GFP_NOIO);
1033  			if (!smallbuf)
1034  				return buf;
1035  			memcpy(smallbuf, buf, len);
1036  		}
1037  		kfree(buf);
1038  	}
1039  	return smallbuf;
1040  }
1041  EXPORT_SYMBOL_GPL(usb_cache_string);
1042  
1043  /*
1044   * usb_get_device_descriptor - read the device descriptor
1045   * @udev: the device whose device descriptor should be read
1046   *
1047   * Context: task context, might sleep.
1048   *
1049   * Not exported, only for use by the core.  If drivers really want to read
1050   * the device descriptor directly, they can call usb_get_descriptor() with
1051   * type = USB_DT_DEVICE and index = 0.
1052   *
1053   * Returns: a pointer to a dynamically allocated usb_device_descriptor
1054   * structure (which the caller must deallocate), or an ERR_PTR value.
1055   */
usb_get_device_descriptor(struct usb_device * udev)1056  struct usb_device_descriptor *usb_get_device_descriptor(struct usb_device *udev)
1057  {
1058  	struct usb_device_descriptor *desc;
1059  	int ret;
1060  
1061  	desc = kmalloc(sizeof(*desc), GFP_NOIO);
1062  	if (!desc)
1063  		return ERR_PTR(-ENOMEM);
1064  
1065  	ret = usb_get_descriptor(udev, USB_DT_DEVICE, 0, desc, sizeof(*desc));
1066  	if (ret == sizeof(*desc))
1067  		return desc;
1068  
1069  	if (ret >= 0)
1070  		ret = -EMSGSIZE;
1071  	kfree(desc);
1072  	return ERR_PTR(ret);
1073  }
1074  
1075  /*
1076   * usb_set_isoch_delay - informs the device of the packet transmit delay
1077   * @dev: the device whose delay is to be informed
1078   * Context: task context, might sleep
1079   *
1080   * Since this is an optional request, we don't bother if it fails.
1081   */
usb_set_isoch_delay(struct usb_device * dev)1082  int usb_set_isoch_delay(struct usb_device *dev)
1083  {
1084  	/* skip hub devices */
1085  	if (dev->descriptor.bDeviceClass == USB_CLASS_HUB)
1086  		return 0;
1087  
1088  	/* skip non-SS/non-SSP devices */
1089  	if (dev->speed < USB_SPEED_SUPER)
1090  		return 0;
1091  
1092  	return usb_control_msg_send(dev, 0,
1093  			USB_REQ_SET_ISOCH_DELAY,
1094  			USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
1095  			dev->hub_delay, 0, NULL, 0,
1096  			USB_CTRL_SET_TIMEOUT,
1097  			GFP_NOIO);
1098  }
1099  
1100  /**
1101   * usb_get_status - issues a GET_STATUS call
1102   * @dev: the device whose status is being checked
1103   * @recip: USB_RECIP_*; for device, interface, or endpoint
1104   * @type: USB_STATUS_TYPE_*; for standard or PTM status types
1105   * @target: zero (for device), else interface or endpoint number
1106   * @data: pointer to two bytes of bitmap data
1107   *
1108   * Context: task context, might sleep.
1109   *
1110   * Returns device, interface, or endpoint status.  Normally only of
1111   * interest to see if the device is self powered, or has enabled the
1112   * remote wakeup facility; or whether a bulk or interrupt endpoint
1113   * is halted ("stalled").
1114   *
1115   * Bits in these status bitmaps are set using the SET_FEATURE request,
1116   * and cleared using the CLEAR_FEATURE request.  The usb_clear_halt()
1117   * function should be used to clear halt ("stall") status.
1118   *
1119   * This call is synchronous, and may not be used in an interrupt context.
1120   *
1121   * Returns 0 and the status value in *@data (in host byte order) on success,
1122   * or else the status code from the underlying usb_control_msg() call.
1123   */
usb_get_status(struct usb_device * dev,int recip,int type,int target,void * data)1124  int usb_get_status(struct usb_device *dev, int recip, int type, int target,
1125  		void *data)
1126  {
1127  	int ret;
1128  	void *status;
1129  	int length;
1130  
1131  	switch (type) {
1132  	case USB_STATUS_TYPE_STANDARD:
1133  		length = 2;
1134  		break;
1135  	case USB_STATUS_TYPE_PTM:
1136  		if (recip != USB_RECIP_DEVICE)
1137  			return -EINVAL;
1138  
1139  		length = 4;
1140  		break;
1141  	default:
1142  		return -EINVAL;
1143  	}
1144  
1145  	status =  kmalloc(length, GFP_KERNEL);
1146  	if (!status)
1147  		return -ENOMEM;
1148  
1149  	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
1150  		USB_REQ_GET_STATUS, USB_DIR_IN | recip, USB_STATUS_TYPE_STANDARD,
1151  		target, status, length, USB_CTRL_GET_TIMEOUT);
1152  
1153  	switch (ret) {
1154  	case 4:
1155  		if (type != USB_STATUS_TYPE_PTM) {
1156  			ret = -EIO;
1157  			break;
1158  		}
1159  
1160  		*(u32 *) data = le32_to_cpu(*(__le32 *) status);
1161  		ret = 0;
1162  		break;
1163  	case 2:
1164  		if (type != USB_STATUS_TYPE_STANDARD) {
1165  			ret = -EIO;
1166  			break;
1167  		}
1168  
1169  		*(u16 *) data = le16_to_cpu(*(__le16 *) status);
1170  		ret = 0;
1171  		break;
1172  	default:
1173  		ret = -EIO;
1174  	}
1175  
1176  	kfree(status);
1177  	return ret;
1178  }
1179  EXPORT_SYMBOL_GPL(usb_get_status);
1180  
1181  /**
1182   * usb_clear_halt - tells device to clear endpoint halt/stall condition
1183   * @dev: device whose endpoint is halted
1184   * @pipe: endpoint "pipe" being cleared
1185   *
1186   * Context: task context, might sleep.
1187   *
1188   * This is used to clear halt conditions for bulk and interrupt endpoints,
1189   * as reported by URB completion status.  Endpoints that are halted are
1190   * sometimes referred to as being "stalled".  Such endpoints are unable
1191   * to transmit or receive data until the halt status is cleared.  Any URBs
1192   * queued for such an endpoint should normally be unlinked by the driver
1193   * before clearing the halt condition, as described in sections 5.7.5
1194   * and 5.8.5 of the USB 2.0 spec.
1195   *
1196   * Note that control and isochronous endpoints don't halt, although control
1197   * endpoints report "protocol stall" (for unsupported requests) using the
1198   * same status code used to report a true stall.
1199   *
1200   * This call is synchronous, and may not be used in an interrupt context.
1201   * If a thread in your driver uses this call, make sure your disconnect()
1202   * method can wait for it to complete.
1203   *
1204   * Return: Zero on success, or else the status code returned by the
1205   * underlying usb_control_msg() call.
1206   */
usb_clear_halt(struct usb_device * dev,int pipe)1207  int usb_clear_halt(struct usb_device *dev, int pipe)
1208  {
1209  	int result;
1210  	int endp = usb_pipeendpoint(pipe);
1211  
1212  	if (usb_pipein(pipe))
1213  		endp |= USB_DIR_IN;
1214  
1215  	/* we don't care if it wasn't halted first. in fact some devices
1216  	 * (like some ibmcam model 1 units) seem to expect hosts to make
1217  	 * this request for iso endpoints, which can't halt!
1218  	 */
1219  	result = usb_control_msg_send(dev, 0,
1220  				      USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
1221  				      USB_ENDPOINT_HALT, endp, NULL, 0,
1222  				      USB_CTRL_SET_TIMEOUT, GFP_NOIO);
1223  
1224  	/* don't un-halt or force to DATA0 except on success */
1225  	if (result)
1226  		return result;
1227  
1228  	/* NOTE:  seems like Microsoft and Apple don't bother verifying
1229  	 * the clear "took", so some devices could lock up if you check...
1230  	 * such as the Hagiwara FlashGate DUAL.  So we won't bother.
1231  	 *
1232  	 * NOTE:  make sure the logic here doesn't diverge much from
1233  	 * the copy in usb-storage, for as long as we need two copies.
1234  	 */
1235  
1236  	usb_reset_endpoint(dev, endp);
1237  
1238  	return 0;
1239  }
1240  EXPORT_SYMBOL_GPL(usb_clear_halt);
1241  
create_intf_ep_devs(struct usb_interface * intf)1242  static int create_intf_ep_devs(struct usb_interface *intf)
1243  {
1244  	struct usb_device *udev = interface_to_usbdev(intf);
1245  	struct usb_host_interface *alt = intf->cur_altsetting;
1246  	int i;
1247  
1248  	if (intf->ep_devs_created || intf->unregistering)
1249  		return 0;
1250  
1251  	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1252  		(void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev);
1253  	intf->ep_devs_created = 1;
1254  	return 0;
1255  }
1256  
remove_intf_ep_devs(struct usb_interface * intf)1257  static void remove_intf_ep_devs(struct usb_interface *intf)
1258  {
1259  	struct usb_host_interface *alt = intf->cur_altsetting;
1260  	int i;
1261  
1262  	if (!intf->ep_devs_created)
1263  		return;
1264  
1265  	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1266  		usb_remove_ep_devs(&alt->endpoint[i]);
1267  	intf->ep_devs_created = 0;
1268  }
1269  
1270  /**
1271   * usb_disable_endpoint -- Disable an endpoint by address
1272   * @dev: the device whose endpoint is being disabled
1273   * @epaddr: the endpoint's address.  Endpoint number for output,
1274   *	endpoint number + USB_DIR_IN for input
1275   * @reset_hardware: flag to erase any endpoint state stored in the
1276   *	controller hardware
1277   *
1278   * Disables the endpoint for URB submission and nukes all pending URBs.
1279   * If @reset_hardware is set then also deallocates hcd/hardware state
1280   * for the endpoint.
1281   */
usb_disable_endpoint(struct usb_device * dev,unsigned int epaddr,bool reset_hardware)1282  void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
1283  		bool reset_hardware)
1284  {
1285  	unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1286  	struct usb_host_endpoint *ep;
1287  
1288  	if (!dev)
1289  		return;
1290  
1291  	if (usb_endpoint_out(epaddr)) {
1292  		ep = dev->ep_out[epnum];
1293  		if (reset_hardware && epnum != 0)
1294  			dev->ep_out[epnum] = NULL;
1295  	} else {
1296  		ep = dev->ep_in[epnum];
1297  		if (reset_hardware && epnum != 0)
1298  			dev->ep_in[epnum] = NULL;
1299  	}
1300  	if (ep) {
1301  		ep->enabled = 0;
1302  		usb_hcd_flush_endpoint(dev, ep);
1303  		if (reset_hardware)
1304  			usb_hcd_disable_endpoint(dev, ep);
1305  	}
1306  }
1307  
1308  /**
1309   * usb_reset_endpoint - Reset an endpoint's state.
1310   * @dev: the device whose endpoint is to be reset
1311   * @epaddr: the endpoint's address.  Endpoint number for output,
1312   *	endpoint number + USB_DIR_IN for input
1313   *
1314   * Resets any host-side endpoint state such as the toggle bit,
1315   * sequence number or current window.
1316   */
usb_reset_endpoint(struct usb_device * dev,unsigned int epaddr)1317  void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr)
1318  {
1319  	unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1320  	struct usb_host_endpoint *ep;
1321  
1322  	if (usb_endpoint_out(epaddr))
1323  		ep = dev->ep_out[epnum];
1324  	else
1325  		ep = dev->ep_in[epnum];
1326  	if (ep)
1327  		usb_hcd_reset_endpoint(dev, ep);
1328  }
1329  EXPORT_SYMBOL_GPL(usb_reset_endpoint);
1330  
1331  
1332  /**
1333   * usb_disable_interface -- Disable all endpoints for an interface
1334   * @dev: the device whose interface is being disabled
1335   * @intf: pointer to the interface descriptor
1336   * @reset_hardware: flag to erase any endpoint state stored in the
1337   *	controller hardware
1338   *
1339   * Disables all the endpoints for the interface's current altsetting.
1340   */
usb_disable_interface(struct usb_device * dev,struct usb_interface * intf,bool reset_hardware)1341  void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
1342  		bool reset_hardware)
1343  {
1344  	struct usb_host_interface *alt = intf->cur_altsetting;
1345  	int i;
1346  
1347  	for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
1348  		usb_disable_endpoint(dev,
1349  				alt->endpoint[i].desc.bEndpointAddress,
1350  				reset_hardware);
1351  	}
1352  }
1353  
1354  /*
1355   * usb_disable_device_endpoints -- Disable all endpoints for a device
1356   * @dev: the device whose endpoints are being disabled
1357   * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1358   */
usb_disable_device_endpoints(struct usb_device * dev,int skip_ep0)1359  static void usb_disable_device_endpoints(struct usb_device *dev, int skip_ep0)
1360  {
1361  	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1362  	int i;
1363  
1364  	if (hcd->driver->check_bandwidth) {
1365  		/* First pass: Cancel URBs, leave endpoint pointers intact. */
1366  		for (i = skip_ep0; i < 16; ++i) {
1367  			usb_disable_endpoint(dev, i, false);
1368  			usb_disable_endpoint(dev, i + USB_DIR_IN, false);
1369  		}
1370  		/* Remove endpoints from the host controller internal state */
1371  		mutex_lock(hcd->bandwidth_mutex);
1372  		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1373  		mutex_unlock(hcd->bandwidth_mutex);
1374  	}
1375  	/* Second pass: remove endpoint pointers */
1376  	for (i = skip_ep0; i < 16; ++i) {
1377  		usb_disable_endpoint(dev, i, true);
1378  		usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1379  	}
1380  }
1381  
1382  /**
1383   * usb_disable_device - Disable all the endpoints for a USB device
1384   * @dev: the device whose endpoints are being disabled
1385   * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1386   *
1387   * Disables all the device's endpoints, potentially including endpoint 0.
1388   * Deallocates hcd/hardware state for the endpoints (nuking all or most
1389   * pending urbs) and usbcore state for the interfaces, so that usbcore
1390   * must usb_set_configuration() before any interfaces could be used.
1391   */
usb_disable_device(struct usb_device * dev,int skip_ep0)1392  void usb_disable_device(struct usb_device *dev, int skip_ep0)
1393  {
1394  	int i;
1395  
1396  	/* getting rid of interfaces will disconnect
1397  	 * any drivers bound to them (a key side effect)
1398  	 */
1399  	if (dev->actconfig) {
1400  		/*
1401  		 * FIXME: In order to avoid self-deadlock involving the
1402  		 * bandwidth_mutex, we have to mark all the interfaces
1403  		 * before unregistering any of them.
1404  		 */
1405  		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
1406  			dev->actconfig->interface[i]->unregistering = 1;
1407  
1408  		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1409  			struct usb_interface	*interface;
1410  
1411  			/* remove this interface if it has been registered */
1412  			interface = dev->actconfig->interface[i];
1413  			if (!device_is_registered(&interface->dev))
1414  				continue;
1415  			dev_dbg(&dev->dev, "unregistering interface %s\n",
1416  				dev_name(&interface->dev));
1417  			remove_intf_ep_devs(interface);
1418  			device_del(&interface->dev);
1419  		}
1420  
1421  		/* Now that the interfaces are unbound, nobody should
1422  		 * try to access them.
1423  		 */
1424  		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1425  			put_device(&dev->actconfig->interface[i]->dev);
1426  			dev->actconfig->interface[i] = NULL;
1427  		}
1428  
1429  		usb_disable_usb2_hardware_lpm(dev);
1430  		usb_unlocked_disable_lpm(dev);
1431  		usb_disable_ltm(dev);
1432  
1433  		dev->actconfig = NULL;
1434  		if (dev->state == USB_STATE_CONFIGURED)
1435  			usb_set_device_state(dev, USB_STATE_ADDRESS);
1436  	}
1437  
1438  	dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
1439  		skip_ep0 ? "non-ep0" : "all");
1440  
1441  	usb_disable_device_endpoints(dev, skip_ep0);
1442  }
1443  
1444  /**
1445   * usb_enable_endpoint - Enable an endpoint for USB communications
1446   * @dev: the device whose interface is being enabled
1447   * @ep: the endpoint
1448   * @reset_ep: flag to reset the endpoint state
1449   *
1450   * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
1451   * For control endpoints, both the input and output sides are handled.
1452   */
usb_enable_endpoint(struct usb_device * dev,struct usb_host_endpoint * ep,bool reset_ep)1453  void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep,
1454  		bool reset_ep)
1455  {
1456  	int epnum = usb_endpoint_num(&ep->desc);
1457  	int is_out = usb_endpoint_dir_out(&ep->desc);
1458  	int is_control = usb_endpoint_xfer_control(&ep->desc);
1459  
1460  	if (reset_ep)
1461  		usb_hcd_reset_endpoint(dev, ep);
1462  	if (is_out || is_control)
1463  		dev->ep_out[epnum] = ep;
1464  	if (!is_out || is_control)
1465  		dev->ep_in[epnum] = ep;
1466  	ep->enabled = 1;
1467  }
1468  
1469  /**
1470   * usb_enable_interface - Enable all the endpoints for an interface
1471   * @dev: the device whose interface is being enabled
1472   * @intf: pointer to the interface descriptor
1473   * @reset_eps: flag to reset the endpoints' state
1474   *
1475   * Enables all the endpoints for the interface's current altsetting.
1476   */
usb_enable_interface(struct usb_device * dev,struct usb_interface * intf,bool reset_eps)1477  void usb_enable_interface(struct usb_device *dev,
1478  		struct usb_interface *intf, bool reset_eps)
1479  {
1480  	struct usb_host_interface *alt = intf->cur_altsetting;
1481  	int i;
1482  
1483  	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1484  		usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps);
1485  }
1486  
1487  /**
1488   * usb_set_interface - Makes a particular alternate setting be current
1489   * @dev: the device whose interface is being updated
1490   * @interface: the interface being updated
1491   * @alternate: the setting being chosen.
1492   *
1493   * Context: task context, might sleep.
1494   *
1495   * This is used to enable data transfers on interfaces that may not
1496   * be enabled by default.  Not all devices support such configurability.
1497   * Only the driver bound to an interface may change its setting.
1498   *
1499   * Within any given configuration, each interface may have several
1500   * alternative settings.  These are often used to control levels of
1501   * bandwidth consumption.  For example, the default setting for a high
1502   * speed interrupt endpoint may not send more than 64 bytes per microframe,
1503   * while interrupt transfers of up to 3KBytes per microframe are legal.
1504   * Also, isochronous endpoints may never be part of an
1505   * interface's default setting.  To access such bandwidth, alternate
1506   * interface settings must be made current.
1507   *
1508   * Note that in the Linux USB subsystem, bandwidth associated with
1509   * an endpoint in a given alternate setting is not reserved until an URB
1510   * is submitted that needs that bandwidth.  Some other operating systems
1511   * allocate bandwidth early, when a configuration is chosen.
1512   *
1513   * xHCI reserves bandwidth and configures the alternate setting in
1514   * usb_hcd_alloc_bandwidth(). If it fails the original interface altsetting
1515   * may be disabled. Drivers cannot rely on any particular alternate
1516   * setting being in effect after a failure.
1517   *
1518   * This call is synchronous, and may not be used in an interrupt context.
1519   * Also, drivers must not change altsettings while urbs are scheduled for
1520   * endpoints in that interface; all such urbs must first be completed
1521   * (perhaps forced by unlinking). If a thread in your driver uses this call,
1522   * make sure your disconnect() method can wait for it to complete.
1523   *
1524   * Return: Zero on success, or else the status code returned by the
1525   * underlying usb_control_msg() call.
1526   */
usb_set_interface(struct usb_device * dev,int interface,int alternate)1527  int usb_set_interface(struct usb_device *dev, int interface, int alternate)
1528  {
1529  	struct usb_interface *iface;
1530  	struct usb_host_interface *alt;
1531  	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1532  	int i, ret, manual = 0;
1533  	unsigned int epaddr;
1534  	unsigned int pipe;
1535  
1536  	if (dev->state == USB_STATE_SUSPENDED)
1537  		return -EHOSTUNREACH;
1538  
1539  	iface = usb_ifnum_to_if(dev, interface);
1540  	if (!iface) {
1541  		dev_dbg(&dev->dev, "selecting invalid interface %d\n",
1542  			interface);
1543  		return -EINVAL;
1544  	}
1545  	if (iface->unregistering)
1546  		return -ENODEV;
1547  
1548  	alt = usb_altnum_to_altsetting(iface, alternate);
1549  	if (!alt) {
1550  		dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
1551  			 alternate);
1552  		return -EINVAL;
1553  	}
1554  	/*
1555  	 * usb3 hosts configure the interface in usb_hcd_alloc_bandwidth,
1556  	 * including freeing dropped endpoint ring buffers.
1557  	 * Make sure the interface endpoints are flushed before that
1558  	 */
1559  	usb_disable_interface(dev, iface, false);
1560  
1561  	/* Make sure we have enough bandwidth for this alternate interface.
1562  	 * Remove the current alt setting and add the new alt setting.
1563  	 */
1564  	mutex_lock(hcd->bandwidth_mutex);
1565  	/* Disable LPM, and re-enable it once the new alt setting is installed,
1566  	 * so that the xHCI driver can recalculate the U1/U2 timeouts.
1567  	 */
1568  	if (usb_disable_lpm(dev)) {
1569  		dev_err(&iface->dev, "%s Failed to disable LPM\n", __func__);
1570  		mutex_unlock(hcd->bandwidth_mutex);
1571  		return -ENOMEM;
1572  	}
1573  	/* Changing alt-setting also frees any allocated streams */
1574  	for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
1575  		iface->cur_altsetting->endpoint[i].streams = 0;
1576  
1577  	ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
1578  	if (ret < 0) {
1579  		dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
1580  				alternate);
1581  		usb_enable_lpm(dev);
1582  		mutex_unlock(hcd->bandwidth_mutex);
1583  		return ret;
1584  	}
1585  
1586  	if (dev->quirks & USB_QUIRK_NO_SET_INTF)
1587  		ret = -EPIPE;
1588  	else
1589  		ret = usb_control_msg_send(dev, 0,
1590  					   USB_REQ_SET_INTERFACE,
1591  					   USB_RECIP_INTERFACE, alternate,
1592  					   interface, NULL, 0, 5000,
1593  					   GFP_NOIO);
1594  
1595  	/* 9.4.10 says devices don't need this and are free to STALL the
1596  	 * request if the interface only has one alternate setting.
1597  	 */
1598  	if (ret == -EPIPE && iface->num_altsetting == 1) {
1599  		dev_dbg(&dev->dev,
1600  			"manual set_interface for iface %d, alt %d\n",
1601  			interface, alternate);
1602  		manual = 1;
1603  	} else if (ret) {
1604  		/* Re-instate the old alt setting */
1605  		usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
1606  		usb_enable_lpm(dev);
1607  		mutex_unlock(hcd->bandwidth_mutex);
1608  		return ret;
1609  	}
1610  	mutex_unlock(hcd->bandwidth_mutex);
1611  
1612  	/* FIXME drivers shouldn't need to replicate/bugfix the logic here
1613  	 * when they implement async or easily-killable versions of this or
1614  	 * other "should-be-internal" functions (like clear_halt).
1615  	 * should hcd+usbcore postprocess control requests?
1616  	 */
1617  
1618  	/* prevent submissions using previous endpoint settings */
1619  	if (iface->cur_altsetting != alt) {
1620  		remove_intf_ep_devs(iface);
1621  		usb_remove_sysfs_intf_files(iface);
1622  	}
1623  	usb_disable_interface(dev, iface, true);
1624  
1625  	iface->cur_altsetting = alt;
1626  
1627  	/* Now that the interface is installed, re-enable LPM. */
1628  	usb_unlocked_enable_lpm(dev);
1629  
1630  	/* If the interface only has one altsetting and the device didn't
1631  	 * accept the request, we attempt to carry out the equivalent action
1632  	 * by manually clearing the HALT feature for each endpoint in the
1633  	 * new altsetting.
1634  	 */
1635  	if (manual) {
1636  		for (i = 0; i < alt->desc.bNumEndpoints; i++) {
1637  			epaddr = alt->endpoint[i].desc.bEndpointAddress;
1638  			pipe = __create_pipe(dev,
1639  					USB_ENDPOINT_NUMBER_MASK & epaddr) |
1640  					(usb_endpoint_out(epaddr) ?
1641  					USB_DIR_OUT : USB_DIR_IN);
1642  
1643  			usb_clear_halt(dev, pipe);
1644  		}
1645  	}
1646  
1647  	/* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1648  	 *
1649  	 * Note:
1650  	 * Despite EP0 is always present in all interfaces/AS, the list of
1651  	 * endpoints from the descriptor does not contain EP0. Due to its
1652  	 * omnipresence one might expect EP0 being considered "affected" by
1653  	 * any SetInterface request and hence assume toggles need to be reset.
1654  	 * However, EP0 toggles are re-synced for every individual transfer
1655  	 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1656  	 * (Likewise, EP0 never "halts" on well designed devices.)
1657  	 */
1658  	usb_enable_interface(dev, iface, true);
1659  	if (device_is_registered(&iface->dev)) {
1660  		usb_create_sysfs_intf_files(iface);
1661  		create_intf_ep_devs(iface);
1662  	}
1663  	return 0;
1664  }
1665  EXPORT_SYMBOL_GPL(usb_set_interface);
1666  
1667  /**
1668   * usb_reset_configuration - lightweight device reset
1669   * @dev: the device whose configuration is being reset
1670   *
1671   * This issues a standard SET_CONFIGURATION request to the device using
1672   * the current configuration.  The effect is to reset most USB-related
1673   * state in the device, including interface altsettings (reset to zero),
1674   * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
1675   * endpoints).  Other usbcore state is unchanged, including bindings of
1676   * usb device drivers to interfaces.
1677   *
1678   * Because this affects multiple interfaces, avoid using this with composite
1679   * (multi-interface) devices.  Instead, the driver for each interface may
1680   * use usb_set_interface() on the interfaces it claims.  Be careful though;
1681   * some devices don't support the SET_INTERFACE request, and others won't
1682   * reset all the interface state (notably endpoint state).  Resetting the whole
1683   * configuration would affect other drivers' interfaces.
1684   *
1685   * The caller must own the device lock.
1686   *
1687   * Return: Zero on success, else a negative error code.
1688   *
1689   * If this routine fails the device will probably be in an unusable state
1690   * with endpoints disabled, and interfaces only partially enabled.
1691   */
usb_reset_configuration(struct usb_device * dev)1692  int usb_reset_configuration(struct usb_device *dev)
1693  {
1694  	int			i, retval;
1695  	struct usb_host_config	*config;
1696  	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1697  
1698  	if (dev->state == USB_STATE_SUSPENDED)
1699  		return -EHOSTUNREACH;
1700  
1701  	/* caller must have locked the device and must own
1702  	 * the usb bus readlock (so driver bindings are stable);
1703  	 * calls during probe() are fine
1704  	 */
1705  
1706  	usb_disable_device_endpoints(dev, 1); /* skip ep0*/
1707  
1708  	config = dev->actconfig;
1709  	retval = 0;
1710  	mutex_lock(hcd->bandwidth_mutex);
1711  	/* Disable LPM, and re-enable it once the configuration is reset, so
1712  	 * that the xHCI driver can recalculate the U1/U2 timeouts.
1713  	 */
1714  	if (usb_disable_lpm(dev)) {
1715  		dev_err(&dev->dev, "%s Failed to disable LPM\n", __func__);
1716  		mutex_unlock(hcd->bandwidth_mutex);
1717  		return -ENOMEM;
1718  	}
1719  
1720  	/* xHCI adds all endpoints in usb_hcd_alloc_bandwidth */
1721  	retval = usb_hcd_alloc_bandwidth(dev, config, NULL, NULL);
1722  	if (retval < 0) {
1723  		usb_enable_lpm(dev);
1724  		mutex_unlock(hcd->bandwidth_mutex);
1725  		return retval;
1726  	}
1727  	retval = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
1728  				      config->desc.bConfigurationValue, 0,
1729  				      NULL, 0, USB_CTRL_SET_TIMEOUT,
1730  				      GFP_NOIO);
1731  	if (retval) {
1732  		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1733  		usb_enable_lpm(dev);
1734  		mutex_unlock(hcd->bandwidth_mutex);
1735  		return retval;
1736  	}
1737  	mutex_unlock(hcd->bandwidth_mutex);
1738  
1739  	/* re-init hc/hcd interface/endpoint state */
1740  	for (i = 0; i < config->desc.bNumInterfaces; i++) {
1741  		struct usb_interface *intf = config->interface[i];
1742  		struct usb_host_interface *alt;
1743  
1744  		alt = usb_altnum_to_altsetting(intf, 0);
1745  
1746  		/* No altsetting 0?  We'll assume the first altsetting.
1747  		 * We could use a GetInterface call, but if a device is
1748  		 * so non-compliant that it doesn't have altsetting 0
1749  		 * then I wouldn't trust its reply anyway.
1750  		 */
1751  		if (!alt)
1752  			alt = &intf->altsetting[0];
1753  
1754  		if (alt != intf->cur_altsetting) {
1755  			remove_intf_ep_devs(intf);
1756  			usb_remove_sysfs_intf_files(intf);
1757  		}
1758  		intf->cur_altsetting = alt;
1759  		usb_enable_interface(dev, intf, true);
1760  		if (device_is_registered(&intf->dev)) {
1761  			usb_create_sysfs_intf_files(intf);
1762  			create_intf_ep_devs(intf);
1763  		}
1764  	}
1765  	/* Now that the interfaces are installed, re-enable LPM. */
1766  	usb_unlocked_enable_lpm(dev);
1767  	return 0;
1768  }
1769  EXPORT_SYMBOL_GPL(usb_reset_configuration);
1770  
usb_release_interface(struct device * dev)1771  static void usb_release_interface(struct device *dev)
1772  {
1773  	struct usb_interface *intf = to_usb_interface(dev);
1774  	struct usb_interface_cache *intfc =
1775  			altsetting_to_usb_interface_cache(intf->altsetting);
1776  
1777  	kref_put(&intfc->ref, usb_release_interface_cache);
1778  	usb_put_dev(interface_to_usbdev(intf));
1779  	of_node_put(dev->of_node);
1780  	kfree(intf);
1781  }
1782  
1783  /*
1784   * usb_deauthorize_interface - deauthorize an USB interface
1785   *
1786   * @intf: USB interface structure
1787   */
usb_deauthorize_interface(struct usb_interface * intf)1788  void usb_deauthorize_interface(struct usb_interface *intf)
1789  {
1790  	struct device *dev = &intf->dev;
1791  
1792  	device_lock(dev->parent);
1793  
1794  	if (intf->authorized) {
1795  		device_lock(dev);
1796  		intf->authorized = 0;
1797  		device_unlock(dev);
1798  
1799  		usb_forced_unbind_intf(intf);
1800  	}
1801  
1802  	device_unlock(dev->parent);
1803  }
1804  
1805  /*
1806   * usb_authorize_interface - authorize an USB interface
1807   *
1808   * @intf: USB interface structure
1809   */
usb_authorize_interface(struct usb_interface * intf)1810  void usb_authorize_interface(struct usb_interface *intf)
1811  {
1812  	struct device *dev = &intf->dev;
1813  
1814  	if (!intf->authorized) {
1815  		device_lock(dev);
1816  		intf->authorized = 1; /* authorize interface */
1817  		device_unlock(dev);
1818  	}
1819  }
1820  
usb_if_uevent(const struct device * dev,struct kobj_uevent_env * env)1821  static int usb_if_uevent(const struct device *dev, struct kobj_uevent_env *env)
1822  {
1823  	const struct usb_device *usb_dev;
1824  	const struct usb_interface *intf;
1825  	const struct usb_host_interface *alt;
1826  
1827  	intf = to_usb_interface(dev);
1828  	usb_dev = interface_to_usbdev(intf);
1829  	alt = intf->cur_altsetting;
1830  
1831  	if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
1832  		   alt->desc.bInterfaceClass,
1833  		   alt->desc.bInterfaceSubClass,
1834  		   alt->desc.bInterfaceProtocol))
1835  		return -ENOMEM;
1836  
1837  	if (add_uevent_var(env,
1838  		   "MODALIAS=usb:"
1839  		   "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X",
1840  		   le16_to_cpu(usb_dev->descriptor.idVendor),
1841  		   le16_to_cpu(usb_dev->descriptor.idProduct),
1842  		   le16_to_cpu(usb_dev->descriptor.bcdDevice),
1843  		   usb_dev->descriptor.bDeviceClass,
1844  		   usb_dev->descriptor.bDeviceSubClass,
1845  		   usb_dev->descriptor.bDeviceProtocol,
1846  		   alt->desc.bInterfaceClass,
1847  		   alt->desc.bInterfaceSubClass,
1848  		   alt->desc.bInterfaceProtocol,
1849  		   alt->desc.bInterfaceNumber))
1850  		return -ENOMEM;
1851  
1852  	return 0;
1853  }
1854  
1855  const struct device_type usb_if_device_type = {
1856  	.name =		"usb_interface",
1857  	.release =	usb_release_interface,
1858  	.uevent =	usb_if_uevent,
1859  };
1860  
find_iad(struct usb_device * dev,struct usb_host_config * config,u8 inum)1861  static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
1862  						struct usb_host_config *config,
1863  						u8 inum)
1864  {
1865  	struct usb_interface_assoc_descriptor *retval = NULL;
1866  	struct usb_interface_assoc_descriptor *intf_assoc;
1867  	int first_intf;
1868  	int last_intf;
1869  	int i;
1870  
1871  	for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
1872  		intf_assoc = config->intf_assoc[i];
1873  		if (intf_assoc->bInterfaceCount == 0)
1874  			continue;
1875  
1876  		first_intf = intf_assoc->bFirstInterface;
1877  		last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
1878  		if (inum >= first_intf && inum <= last_intf) {
1879  			if (!retval)
1880  				retval = intf_assoc;
1881  			else
1882  				dev_err(&dev->dev, "Interface #%d referenced"
1883  					" by multiple IADs\n", inum);
1884  		}
1885  	}
1886  
1887  	return retval;
1888  }
1889  
1890  
1891  /*
1892   * Internal function to queue a device reset
1893   * See usb_queue_reset_device() for more details
1894   */
__usb_queue_reset_device(struct work_struct * ws)1895  static void __usb_queue_reset_device(struct work_struct *ws)
1896  {
1897  	int rc;
1898  	struct usb_interface *iface =
1899  		container_of(ws, struct usb_interface, reset_ws);
1900  	struct usb_device *udev = interface_to_usbdev(iface);
1901  
1902  	rc = usb_lock_device_for_reset(udev, iface);
1903  	if (rc >= 0) {
1904  		usb_reset_device(udev);
1905  		usb_unlock_device(udev);
1906  	}
1907  	usb_put_intf(iface);	/* Undo _get_ in usb_queue_reset_device() */
1908  }
1909  
1910  /*
1911   * Internal function to set the wireless_status sysfs attribute
1912   * See usb_set_wireless_status() for more details
1913   */
__usb_wireless_status_intf(struct work_struct * ws)1914  static void __usb_wireless_status_intf(struct work_struct *ws)
1915  {
1916  	struct usb_interface *iface =
1917  		container_of(ws, struct usb_interface, wireless_status_work);
1918  
1919  	device_lock(iface->dev.parent);
1920  	if (iface->sysfs_files_created)
1921  		usb_update_wireless_status_attr(iface);
1922  	device_unlock(iface->dev.parent);
1923  	usb_put_intf(iface);	/* Undo _get_ in usb_set_wireless_status() */
1924  }
1925  
1926  /**
1927   * usb_set_wireless_status - sets the wireless_status struct member
1928   * @iface: the interface to modify
1929   * @status: the new wireless status
1930   *
1931   * Set the wireless_status struct member to the new value, and emit
1932   * sysfs changes as necessary.
1933   *
1934   * Returns: 0 on success, -EALREADY if already set.
1935   */
usb_set_wireless_status(struct usb_interface * iface,enum usb_wireless_status status)1936  int usb_set_wireless_status(struct usb_interface *iface,
1937  		enum usb_wireless_status status)
1938  {
1939  	if (iface->wireless_status == status)
1940  		return -EALREADY;
1941  
1942  	usb_get_intf(iface);
1943  	iface->wireless_status = status;
1944  	schedule_work(&iface->wireless_status_work);
1945  
1946  	return 0;
1947  }
1948  EXPORT_SYMBOL_GPL(usb_set_wireless_status);
1949  
1950  /*
1951   * usb_set_configuration - Makes a particular device setting be current
1952   * @dev: the device whose configuration is being updated
1953   * @configuration: the configuration being chosen.
1954   *
1955   * Context: task context, might sleep. Caller holds device lock.
1956   *
1957   * This is used to enable non-default device modes.  Not all devices
1958   * use this kind of configurability; many devices only have one
1959   * configuration.
1960   *
1961   * @configuration is the value of the configuration to be installed.
1962   * According to the USB spec (e.g. section 9.1.1.5), configuration values
1963   * must be non-zero; a value of zero indicates that the device in
1964   * unconfigured.  However some devices erroneously use 0 as one of their
1965   * configuration values.  To help manage such devices, this routine will
1966   * accept @configuration = -1 as indicating the device should be put in
1967   * an unconfigured state.
1968   *
1969   * USB device configurations may affect Linux interoperability,
1970   * power consumption and the functionality available.  For example,
1971   * the default configuration is limited to using 100mA of bus power,
1972   * so that when certain device functionality requires more power,
1973   * and the device is bus powered, that functionality should be in some
1974   * non-default device configuration.  Other device modes may also be
1975   * reflected as configuration options, such as whether two ISDN
1976   * channels are available independently; and choosing between open
1977   * standard device protocols (like CDC) or proprietary ones.
1978   *
1979   * Note that a non-authorized device (dev->authorized == 0) will only
1980   * be put in unconfigured mode.
1981   *
1982   * Note that USB has an additional level of device configurability,
1983   * associated with interfaces.  That configurability is accessed using
1984   * usb_set_interface().
1985   *
1986   * This call is synchronous. The calling context must be able to sleep,
1987   * must own the device lock, and must not hold the driver model's USB
1988   * bus mutex; usb interface driver probe() methods cannot use this routine.
1989   *
1990   * Returns zero on success, or else the status code returned by the
1991   * underlying call that failed.  On successful completion, each interface
1992   * in the original device configuration has been destroyed, and each one
1993   * in the new configuration has been probed by all relevant usb device
1994   * drivers currently known to the kernel.
1995   */
usb_set_configuration(struct usb_device * dev,int configuration)1996  int usb_set_configuration(struct usb_device *dev, int configuration)
1997  {
1998  	int i, ret;
1999  	struct usb_host_config *cp = NULL;
2000  	struct usb_interface **new_interfaces = NULL;
2001  	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
2002  	int n, nintf;
2003  
2004  	if (dev->authorized == 0 || configuration == -1)
2005  		configuration = 0;
2006  	else {
2007  		for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
2008  			if (dev->config[i].desc.bConfigurationValue ==
2009  					configuration) {
2010  				cp = &dev->config[i];
2011  				break;
2012  			}
2013  		}
2014  	}
2015  	if ((!cp && configuration != 0))
2016  		return -EINVAL;
2017  
2018  	/* The USB spec says configuration 0 means unconfigured.
2019  	 * But if a device includes a configuration numbered 0,
2020  	 * we will accept it as a correctly configured state.
2021  	 * Use -1 if you really want to unconfigure the device.
2022  	 */
2023  	if (cp && configuration == 0)
2024  		dev_warn(&dev->dev, "config 0 descriptor??\n");
2025  
2026  	/* Allocate memory for new interfaces before doing anything else,
2027  	 * so that if we run out then nothing will have changed. */
2028  	n = nintf = 0;
2029  	if (cp) {
2030  		nintf = cp->desc.bNumInterfaces;
2031  		new_interfaces = kmalloc_array(nintf, sizeof(*new_interfaces),
2032  					       GFP_NOIO);
2033  		if (!new_interfaces)
2034  			return -ENOMEM;
2035  
2036  		for (; n < nintf; ++n) {
2037  			new_interfaces[n] = kzalloc(
2038  					sizeof(struct usb_interface),
2039  					GFP_NOIO);
2040  			if (!new_interfaces[n]) {
2041  				ret = -ENOMEM;
2042  free_interfaces:
2043  				while (--n >= 0)
2044  					kfree(new_interfaces[n]);
2045  				kfree(new_interfaces);
2046  				return ret;
2047  			}
2048  		}
2049  
2050  		i = dev->bus_mA - usb_get_max_power(dev, cp);
2051  		if (i < 0)
2052  			dev_warn(&dev->dev, "new config #%d exceeds power "
2053  					"limit by %dmA\n",
2054  					configuration, -i);
2055  	}
2056  
2057  	/* Wake up the device so we can send it the Set-Config request */
2058  	ret = usb_autoresume_device(dev);
2059  	if (ret)
2060  		goto free_interfaces;
2061  
2062  	/* if it's already configured, clear out old state first.
2063  	 * getting rid of old interfaces means unbinding their drivers.
2064  	 */
2065  	if (dev->state != USB_STATE_ADDRESS)
2066  		usb_disable_device(dev, 1);	/* Skip ep0 */
2067  
2068  	/* Get rid of pending async Set-Config requests for this device */
2069  	cancel_async_set_config(dev);
2070  
2071  	/* Make sure we have bandwidth (and available HCD resources) for this
2072  	 * configuration.  Remove endpoints from the schedule if we're dropping
2073  	 * this configuration to set configuration 0.  After this point, the
2074  	 * host controller will not allow submissions to dropped endpoints.  If
2075  	 * this call fails, the device state is unchanged.
2076  	 */
2077  	mutex_lock(hcd->bandwidth_mutex);
2078  	/* Disable LPM, and re-enable it once the new configuration is
2079  	 * installed, so that the xHCI driver can recalculate the U1/U2
2080  	 * timeouts.
2081  	 */
2082  	if (dev->actconfig && usb_disable_lpm(dev)) {
2083  		dev_err(&dev->dev, "%s Failed to disable LPM\n", __func__);
2084  		mutex_unlock(hcd->bandwidth_mutex);
2085  		ret = -ENOMEM;
2086  		goto free_interfaces;
2087  	}
2088  	ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
2089  	if (ret < 0) {
2090  		if (dev->actconfig)
2091  			usb_enable_lpm(dev);
2092  		mutex_unlock(hcd->bandwidth_mutex);
2093  		usb_autosuspend_device(dev);
2094  		goto free_interfaces;
2095  	}
2096  
2097  	/*
2098  	 * Initialize the new interface structures and the
2099  	 * hc/hcd/usbcore interface/endpoint state.
2100  	 */
2101  	for (i = 0; i < nintf; ++i) {
2102  		struct usb_interface_cache *intfc;
2103  		struct usb_interface *intf;
2104  		struct usb_host_interface *alt;
2105  		u8 ifnum;
2106  
2107  		cp->interface[i] = intf = new_interfaces[i];
2108  		intfc = cp->intf_cache[i];
2109  		intf->altsetting = intfc->altsetting;
2110  		intf->num_altsetting = intfc->num_altsetting;
2111  		intf->authorized = !!HCD_INTF_AUTHORIZED(hcd);
2112  		kref_get(&intfc->ref);
2113  
2114  		alt = usb_altnum_to_altsetting(intf, 0);
2115  
2116  		/* No altsetting 0?  We'll assume the first altsetting.
2117  		 * We could use a GetInterface call, but if a device is
2118  		 * so non-compliant that it doesn't have altsetting 0
2119  		 * then I wouldn't trust its reply anyway.
2120  		 */
2121  		if (!alt)
2122  			alt = &intf->altsetting[0];
2123  
2124  		ifnum = alt->desc.bInterfaceNumber;
2125  		intf->intf_assoc = find_iad(dev, cp, ifnum);
2126  		intf->cur_altsetting = alt;
2127  		usb_enable_interface(dev, intf, true);
2128  		intf->dev.parent = &dev->dev;
2129  		if (usb_of_has_combined_node(dev)) {
2130  			device_set_of_node_from_dev(&intf->dev, &dev->dev);
2131  		} else {
2132  			intf->dev.of_node = usb_of_get_interface_node(dev,
2133  					configuration, ifnum);
2134  		}
2135  		ACPI_COMPANION_SET(&intf->dev, ACPI_COMPANION(&dev->dev));
2136  		intf->dev.driver = NULL;
2137  		intf->dev.bus = &usb_bus_type;
2138  		intf->dev.type = &usb_if_device_type;
2139  		intf->dev.groups = usb_interface_groups;
2140  		INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
2141  		INIT_WORK(&intf->wireless_status_work, __usb_wireless_status_intf);
2142  		intf->minor = -1;
2143  		device_initialize(&intf->dev);
2144  		pm_runtime_no_callbacks(&intf->dev);
2145  		dev_set_name(&intf->dev, "%d-%s:%d.%d", dev->bus->busnum,
2146  				dev->devpath, configuration, ifnum);
2147  		usb_get_dev(dev);
2148  	}
2149  	kfree(new_interfaces);
2150  
2151  	ret = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
2152  				   configuration, 0, NULL, 0,
2153  				   USB_CTRL_SET_TIMEOUT, GFP_NOIO);
2154  	if (ret && cp) {
2155  		/*
2156  		 * All the old state is gone, so what else can we do?
2157  		 * The device is probably useless now anyway.
2158  		 */
2159  		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
2160  		for (i = 0; i < nintf; ++i) {
2161  			usb_disable_interface(dev, cp->interface[i], true);
2162  			put_device(&cp->interface[i]->dev);
2163  			cp->interface[i] = NULL;
2164  		}
2165  		cp = NULL;
2166  	}
2167  
2168  	dev->actconfig = cp;
2169  	mutex_unlock(hcd->bandwidth_mutex);
2170  
2171  	if (!cp) {
2172  		usb_set_device_state(dev, USB_STATE_ADDRESS);
2173  
2174  		/* Leave LPM disabled while the device is unconfigured. */
2175  		usb_autosuspend_device(dev);
2176  		return ret;
2177  	}
2178  	usb_set_device_state(dev, USB_STATE_CONFIGURED);
2179  
2180  	if (cp->string == NULL &&
2181  			!(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
2182  		cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
2183  
2184  	/* Now that the interfaces are installed, re-enable LPM. */
2185  	usb_unlocked_enable_lpm(dev);
2186  	/* Enable LTM if it was turned off by usb_disable_device. */
2187  	usb_enable_ltm(dev);
2188  
2189  	/* Now that all the interfaces are set up, register them
2190  	 * to trigger binding of drivers to interfaces.  probe()
2191  	 * routines may install different altsettings and may
2192  	 * claim() any interfaces not yet bound.  Many class drivers
2193  	 * need that: CDC, audio, video, etc.
2194  	 */
2195  	for (i = 0; i < nintf; ++i) {
2196  		struct usb_interface *intf = cp->interface[i];
2197  
2198  		if (intf->dev.of_node &&
2199  		    !of_device_is_available(intf->dev.of_node)) {
2200  			dev_info(&dev->dev, "skipping disabled interface %d\n",
2201  				 intf->cur_altsetting->desc.bInterfaceNumber);
2202  			continue;
2203  		}
2204  
2205  		dev_dbg(&dev->dev,
2206  			"adding %s (config #%d, interface %d)\n",
2207  			dev_name(&intf->dev), configuration,
2208  			intf->cur_altsetting->desc.bInterfaceNumber);
2209  		device_enable_async_suspend(&intf->dev);
2210  		ret = device_add(&intf->dev);
2211  		if (ret != 0) {
2212  			dev_err(&dev->dev, "device_add(%s) --> %d\n",
2213  				dev_name(&intf->dev), ret);
2214  			continue;
2215  		}
2216  		create_intf_ep_devs(intf);
2217  	}
2218  
2219  	usb_autosuspend_device(dev);
2220  	return 0;
2221  }
2222  EXPORT_SYMBOL_GPL(usb_set_configuration);
2223  
2224  static LIST_HEAD(set_config_list);
2225  static DEFINE_SPINLOCK(set_config_lock);
2226  
2227  struct set_config_request {
2228  	struct usb_device	*udev;
2229  	int			config;
2230  	struct work_struct	work;
2231  	struct list_head	node;
2232  };
2233  
2234  /* Worker routine for usb_driver_set_configuration() */
driver_set_config_work(struct work_struct * work)2235  static void driver_set_config_work(struct work_struct *work)
2236  {
2237  	struct set_config_request *req =
2238  		container_of(work, struct set_config_request, work);
2239  	struct usb_device *udev = req->udev;
2240  
2241  	usb_lock_device(udev);
2242  	spin_lock(&set_config_lock);
2243  	list_del(&req->node);
2244  	spin_unlock(&set_config_lock);
2245  
2246  	if (req->config >= -1)		/* Is req still valid? */
2247  		usb_set_configuration(udev, req->config);
2248  	usb_unlock_device(udev);
2249  	usb_put_dev(udev);
2250  	kfree(req);
2251  }
2252  
2253  /* Cancel pending Set-Config requests for a device whose configuration
2254   * was just changed
2255   */
cancel_async_set_config(struct usb_device * udev)2256  static void cancel_async_set_config(struct usb_device *udev)
2257  {
2258  	struct set_config_request *req;
2259  
2260  	spin_lock(&set_config_lock);
2261  	list_for_each_entry(req, &set_config_list, node) {
2262  		if (req->udev == udev)
2263  			req->config = -999;	/* Mark as cancelled */
2264  	}
2265  	spin_unlock(&set_config_lock);
2266  }
2267  
2268  /**
2269   * usb_driver_set_configuration - Provide a way for drivers to change device configurations
2270   * @udev: the device whose configuration is being updated
2271   * @config: the configuration being chosen.
2272   * Context: In process context, must be able to sleep
2273   *
2274   * Device interface drivers are not allowed to change device configurations.
2275   * This is because changing configurations will destroy the interface the
2276   * driver is bound to and create new ones; it would be like a floppy-disk
2277   * driver telling the computer to replace the floppy-disk drive with a
2278   * tape drive!
2279   *
2280   * Still, in certain specialized circumstances the need may arise.  This
2281   * routine gets around the normal restrictions by using a work thread to
2282   * submit the change-config request.
2283   *
2284   * Return: 0 if the request was successfully queued, error code otherwise.
2285   * The caller has no way to know whether the queued request will eventually
2286   * succeed.
2287   */
usb_driver_set_configuration(struct usb_device * udev,int config)2288  int usb_driver_set_configuration(struct usb_device *udev, int config)
2289  {
2290  	struct set_config_request *req;
2291  
2292  	req = kmalloc(sizeof(*req), GFP_KERNEL);
2293  	if (!req)
2294  		return -ENOMEM;
2295  	req->udev = udev;
2296  	req->config = config;
2297  	INIT_WORK(&req->work, driver_set_config_work);
2298  
2299  	spin_lock(&set_config_lock);
2300  	list_add(&req->node, &set_config_list);
2301  	spin_unlock(&set_config_lock);
2302  
2303  	usb_get_dev(udev);
2304  	schedule_work(&req->work);
2305  	return 0;
2306  }
2307  EXPORT_SYMBOL_GPL(usb_driver_set_configuration);
2308  
2309  /**
2310   * cdc_parse_cdc_header - parse the extra headers present in CDC devices
2311   * @hdr: the place to put the results of the parsing
2312   * @intf: the interface for which parsing is requested
2313   * @buffer: pointer to the extra headers to be parsed
2314   * @buflen: length of the extra headers
2315   *
2316   * This evaluates the extra headers present in CDC devices which
2317   * bind the interfaces for data and control and provide details
2318   * about the capabilities of the device.
2319   *
2320   * Return: number of descriptors parsed or -EINVAL
2321   * if the header is contradictory beyond salvage
2322   */
2323  
cdc_parse_cdc_header(struct usb_cdc_parsed_header * hdr,struct usb_interface * intf,u8 * buffer,int buflen)2324  int cdc_parse_cdc_header(struct usb_cdc_parsed_header *hdr,
2325  				struct usb_interface *intf,
2326  				u8 *buffer,
2327  				int buflen)
2328  {
2329  	/* duplicates are ignored */
2330  	struct usb_cdc_union_desc *union_header = NULL;
2331  
2332  	/* duplicates are not tolerated */
2333  	struct usb_cdc_header_desc *header = NULL;
2334  	struct usb_cdc_ether_desc *ether = NULL;
2335  	struct usb_cdc_mdlm_detail_desc *detail = NULL;
2336  	struct usb_cdc_mdlm_desc *desc = NULL;
2337  
2338  	unsigned int elength;
2339  	int cnt = 0;
2340  
2341  	memset(hdr, 0x00, sizeof(struct usb_cdc_parsed_header));
2342  	hdr->phonet_magic_present = false;
2343  	while (buflen > 0) {
2344  		elength = buffer[0];
2345  		if (!elength) {
2346  			dev_err(&intf->dev, "skipping garbage byte\n");
2347  			elength = 1;
2348  			goto next_desc;
2349  		}
2350  		if ((buflen < elength) || (elength < 3)) {
2351  			dev_err(&intf->dev, "invalid descriptor buffer length\n");
2352  			break;
2353  		}
2354  		if (buffer[1] != USB_DT_CS_INTERFACE) {
2355  			dev_err(&intf->dev, "skipping garbage\n");
2356  			goto next_desc;
2357  		}
2358  
2359  		switch (buffer[2]) {
2360  		case USB_CDC_UNION_TYPE: /* we've found it */
2361  			if (elength < sizeof(struct usb_cdc_union_desc))
2362  				goto next_desc;
2363  			if (union_header) {
2364  				dev_err(&intf->dev, "More than one union descriptor, skipping ...\n");
2365  				goto next_desc;
2366  			}
2367  			union_header = (struct usb_cdc_union_desc *)buffer;
2368  			break;
2369  		case USB_CDC_COUNTRY_TYPE:
2370  			if (elength < sizeof(struct usb_cdc_country_functional_desc))
2371  				goto next_desc;
2372  			hdr->usb_cdc_country_functional_desc =
2373  				(struct usb_cdc_country_functional_desc *)buffer;
2374  			break;
2375  		case USB_CDC_HEADER_TYPE:
2376  			if (elength != sizeof(struct usb_cdc_header_desc))
2377  				goto next_desc;
2378  			if (header)
2379  				return -EINVAL;
2380  			header = (struct usb_cdc_header_desc *)buffer;
2381  			break;
2382  		case USB_CDC_ACM_TYPE:
2383  			if (elength < sizeof(struct usb_cdc_acm_descriptor))
2384  				goto next_desc;
2385  			hdr->usb_cdc_acm_descriptor =
2386  				(struct usb_cdc_acm_descriptor *)buffer;
2387  			break;
2388  		case USB_CDC_ETHERNET_TYPE:
2389  			if (elength != sizeof(struct usb_cdc_ether_desc))
2390  				goto next_desc;
2391  			if (ether)
2392  				return -EINVAL;
2393  			ether = (struct usb_cdc_ether_desc *)buffer;
2394  			break;
2395  		case USB_CDC_CALL_MANAGEMENT_TYPE:
2396  			if (elength < sizeof(struct usb_cdc_call_mgmt_descriptor))
2397  				goto next_desc;
2398  			hdr->usb_cdc_call_mgmt_descriptor =
2399  				(struct usb_cdc_call_mgmt_descriptor *)buffer;
2400  			break;
2401  		case USB_CDC_DMM_TYPE:
2402  			if (elength < sizeof(struct usb_cdc_dmm_desc))
2403  				goto next_desc;
2404  			hdr->usb_cdc_dmm_desc =
2405  				(struct usb_cdc_dmm_desc *)buffer;
2406  			break;
2407  		case USB_CDC_MDLM_TYPE:
2408  			if (elength < sizeof(struct usb_cdc_mdlm_desc))
2409  				goto next_desc;
2410  			if (desc)
2411  				return -EINVAL;
2412  			desc = (struct usb_cdc_mdlm_desc *)buffer;
2413  			break;
2414  		case USB_CDC_MDLM_DETAIL_TYPE:
2415  			if (elength < sizeof(struct usb_cdc_mdlm_detail_desc))
2416  				goto next_desc;
2417  			if (detail)
2418  				return -EINVAL;
2419  			detail = (struct usb_cdc_mdlm_detail_desc *)buffer;
2420  			break;
2421  		case USB_CDC_NCM_TYPE:
2422  			if (elength < sizeof(struct usb_cdc_ncm_desc))
2423  				goto next_desc;
2424  			hdr->usb_cdc_ncm_desc = (struct usb_cdc_ncm_desc *)buffer;
2425  			break;
2426  		case USB_CDC_MBIM_TYPE:
2427  			if (elength < sizeof(struct usb_cdc_mbim_desc))
2428  				goto next_desc;
2429  
2430  			hdr->usb_cdc_mbim_desc = (struct usb_cdc_mbim_desc *)buffer;
2431  			break;
2432  		case USB_CDC_MBIM_EXTENDED_TYPE:
2433  			if (elength < sizeof(struct usb_cdc_mbim_extended_desc))
2434  				break;
2435  			hdr->usb_cdc_mbim_extended_desc =
2436  				(struct usb_cdc_mbim_extended_desc *)buffer;
2437  			break;
2438  		case CDC_PHONET_MAGIC_NUMBER:
2439  			hdr->phonet_magic_present = true;
2440  			break;
2441  		default:
2442  			/*
2443  			 * there are LOTS more CDC descriptors that
2444  			 * could legitimately be found here.
2445  			 */
2446  			dev_dbg(&intf->dev, "Ignoring descriptor: type %02x, length %ud\n",
2447  					buffer[2], elength);
2448  			goto next_desc;
2449  		}
2450  		cnt++;
2451  next_desc:
2452  		buflen -= elength;
2453  		buffer += elength;
2454  	}
2455  	hdr->usb_cdc_union_desc = union_header;
2456  	hdr->usb_cdc_header_desc = header;
2457  	hdr->usb_cdc_mdlm_detail_desc = detail;
2458  	hdr->usb_cdc_mdlm_desc = desc;
2459  	hdr->usb_cdc_ether_desc = ether;
2460  	return cnt;
2461  }
2462  
2463  EXPORT_SYMBOL(cdc_parse_cdc_header);
2464