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