xref: /openbmc/linux/drivers/usb/core/message.c (revision de28e469)
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  *
1202  * Return: Zero on success, or else the status code returned by the
1203  * underlying usb_control_msg() call.
1204  */
usb_clear_halt(struct usb_device * dev,int pipe)1205 int usb_clear_halt(struct usb_device *dev, int pipe)
1206 {
1207 	int result;
1208 	int endp = usb_pipeendpoint(pipe);
1209 
1210 	if (usb_pipein(pipe))
1211 		endp |= USB_DIR_IN;
1212 
1213 	/* we don't care if it wasn't halted first. in fact some devices
1214 	 * (like some ibmcam model 1 units) seem to expect hosts to make
1215 	 * this request for iso endpoints, which can't halt!
1216 	 */
1217 	result = usb_control_msg_send(dev, 0,
1218 				      USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
1219 				      USB_ENDPOINT_HALT, endp, NULL, 0,
1220 				      USB_CTRL_SET_TIMEOUT, GFP_NOIO);
1221 
1222 	/* don't un-halt or force to DATA0 except on success */
1223 	if (result)
1224 		return result;
1225 
1226 	/* NOTE:  seems like Microsoft and Apple don't bother verifying
1227 	 * the clear "took", so some devices could lock up if you check...
1228 	 * such as the Hagiwara FlashGate DUAL.  So we won't bother.
1229 	 *
1230 	 * NOTE:  make sure the logic here doesn't diverge much from
1231 	 * the copy in usb-storage, for as long as we need two copies.
1232 	 */
1233 
1234 	usb_reset_endpoint(dev, endp);
1235 
1236 	return 0;
1237 }
1238 EXPORT_SYMBOL_GPL(usb_clear_halt);
1239 
create_intf_ep_devs(struct usb_interface * intf)1240 static int create_intf_ep_devs(struct usb_interface *intf)
1241 {
1242 	struct usb_device *udev = interface_to_usbdev(intf);
1243 	struct usb_host_interface *alt = intf->cur_altsetting;
1244 	int i;
1245 
1246 	if (intf->ep_devs_created || intf->unregistering)
1247 		return 0;
1248 
1249 	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1250 		(void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev);
1251 	intf->ep_devs_created = 1;
1252 	return 0;
1253 }
1254 
remove_intf_ep_devs(struct usb_interface * intf)1255 static void remove_intf_ep_devs(struct usb_interface *intf)
1256 {
1257 	struct usb_host_interface *alt = intf->cur_altsetting;
1258 	int i;
1259 
1260 	if (!intf->ep_devs_created)
1261 		return;
1262 
1263 	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1264 		usb_remove_ep_devs(&alt->endpoint[i]);
1265 	intf->ep_devs_created = 0;
1266 }
1267 
1268 /**
1269  * usb_disable_endpoint -- Disable an endpoint by address
1270  * @dev: the device whose endpoint is being disabled
1271  * @epaddr: the endpoint's address.  Endpoint number for output,
1272  *	endpoint number + USB_DIR_IN for input
1273  * @reset_hardware: flag to erase any endpoint state stored in the
1274  *	controller hardware
1275  *
1276  * Disables the endpoint for URB submission and nukes all pending URBs.
1277  * If @reset_hardware is set then also deallocates hcd/hardware state
1278  * for the endpoint.
1279  */
usb_disable_endpoint(struct usb_device * dev,unsigned int epaddr,bool reset_hardware)1280 void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
1281 		bool reset_hardware)
1282 {
1283 	unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1284 	struct usb_host_endpoint *ep;
1285 
1286 	if (!dev)
1287 		return;
1288 
1289 	if (usb_endpoint_out(epaddr)) {
1290 		ep = dev->ep_out[epnum];
1291 		if (reset_hardware && epnum != 0)
1292 			dev->ep_out[epnum] = NULL;
1293 	} else {
1294 		ep = dev->ep_in[epnum];
1295 		if (reset_hardware && epnum != 0)
1296 			dev->ep_in[epnum] = NULL;
1297 	}
1298 	if (ep) {
1299 		ep->enabled = 0;
1300 		usb_hcd_flush_endpoint(dev, ep);
1301 		if (reset_hardware)
1302 			usb_hcd_disable_endpoint(dev, ep);
1303 	}
1304 }
1305 
1306 /**
1307  * usb_reset_endpoint - Reset an endpoint's state.
1308  * @dev: the device whose endpoint is to be reset
1309  * @epaddr: the endpoint's address.  Endpoint number for output,
1310  *	endpoint number + USB_DIR_IN for input
1311  *
1312  * Resets any host-side endpoint state such as the toggle bit,
1313  * sequence number or current window.
1314  */
usb_reset_endpoint(struct usb_device * dev,unsigned int epaddr)1315 void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr)
1316 {
1317 	unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1318 	struct usb_host_endpoint *ep;
1319 
1320 	if (usb_endpoint_out(epaddr))
1321 		ep = dev->ep_out[epnum];
1322 	else
1323 		ep = dev->ep_in[epnum];
1324 	if (ep)
1325 		usb_hcd_reset_endpoint(dev, ep);
1326 }
1327 EXPORT_SYMBOL_GPL(usb_reset_endpoint);
1328 
1329 
1330 /**
1331  * usb_disable_interface -- Disable all endpoints for an interface
1332  * @dev: the device whose interface is being disabled
1333  * @intf: pointer to the interface descriptor
1334  * @reset_hardware: flag to erase any endpoint state stored in the
1335  *	controller hardware
1336  *
1337  * Disables all the endpoints for the interface's current altsetting.
1338  */
usb_disable_interface(struct usb_device * dev,struct usb_interface * intf,bool reset_hardware)1339 void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
1340 		bool reset_hardware)
1341 {
1342 	struct usb_host_interface *alt = intf->cur_altsetting;
1343 	int i;
1344 
1345 	for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
1346 		usb_disable_endpoint(dev,
1347 				alt->endpoint[i].desc.bEndpointAddress,
1348 				reset_hardware);
1349 	}
1350 }
1351 
1352 /*
1353  * usb_disable_device_endpoints -- Disable all endpoints for a device
1354  * @dev: the device whose endpoints are being disabled
1355  * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1356  */
usb_disable_device_endpoints(struct usb_device * dev,int skip_ep0)1357 static void usb_disable_device_endpoints(struct usb_device *dev, int skip_ep0)
1358 {
1359 	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1360 	int i;
1361 
1362 	if (hcd->driver->check_bandwidth) {
1363 		/* First pass: Cancel URBs, leave endpoint pointers intact. */
1364 		for (i = skip_ep0; i < 16; ++i) {
1365 			usb_disable_endpoint(dev, i, false);
1366 			usb_disable_endpoint(dev, i + USB_DIR_IN, false);
1367 		}
1368 		/* Remove endpoints from the host controller internal state */
1369 		mutex_lock(hcd->bandwidth_mutex);
1370 		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1371 		mutex_unlock(hcd->bandwidth_mutex);
1372 	}
1373 	/* Second pass: remove endpoint pointers */
1374 	for (i = skip_ep0; i < 16; ++i) {
1375 		usb_disable_endpoint(dev, i, true);
1376 		usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1377 	}
1378 }
1379 
1380 /**
1381  * usb_disable_device - Disable all the endpoints for a USB device
1382  * @dev: the device whose endpoints are being disabled
1383  * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1384  *
1385  * Disables all the device's endpoints, potentially including endpoint 0.
1386  * Deallocates hcd/hardware state for the endpoints (nuking all or most
1387  * pending urbs) and usbcore state for the interfaces, so that usbcore
1388  * must usb_set_configuration() before any interfaces could be used.
1389  */
usb_disable_device(struct usb_device * dev,int skip_ep0)1390 void usb_disable_device(struct usb_device *dev, int skip_ep0)
1391 {
1392 	int i;
1393 
1394 	/* getting rid of interfaces will disconnect
1395 	 * any drivers bound to them (a key side effect)
1396 	 */
1397 	if (dev->actconfig) {
1398 		/*
1399 		 * FIXME: In order to avoid self-deadlock involving the
1400 		 * bandwidth_mutex, we have to mark all the interfaces
1401 		 * before unregistering any of them.
1402 		 */
1403 		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
1404 			dev->actconfig->interface[i]->unregistering = 1;
1405 
1406 		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1407 			struct usb_interface	*interface;
1408 
1409 			/* remove this interface if it has been registered */
1410 			interface = dev->actconfig->interface[i];
1411 			if (!device_is_registered(&interface->dev))
1412 				continue;
1413 			dev_dbg(&dev->dev, "unregistering interface %s\n",
1414 				dev_name(&interface->dev));
1415 			remove_intf_ep_devs(interface);
1416 			device_del(&interface->dev);
1417 		}
1418 
1419 		/* Now that the interfaces are unbound, nobody should
1420 		 * try to access them.
1421 		 */
1422 		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1423 			put_device(&dev->actconfig->interface[i]->dev);
1424 			dev->actconfig->interface[i] = NULL;
1425 		}
1426 
1427 		usb_disable_usb2_hardware_lpm(dev);
1428 		usb_unlocked_disable_lpm(dev);
1429 		usb_disable_ltm(dev);
1430 
1431 		dev->actconfig = NULL;
1432 		if (dev->state == USB_STATE_CONFIGURED)
1433 			usb_set_device_state(dev, USB_STATE_ADDRESS);
1434 	}
1435 
1436 	dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
1437 		skip_ep0 ? "non-ep0" : "all");
1438 
1439 	usb_disable_device_endpoints(dev, skip_ep0);
1440 }
1441 
1442 /**
1443  * usb_enable_endpoint - Enable an endpoint for USB communications
1444  * @dev: the device whose interface is being enabled
1445  * @ep: the endpoint
1446  * @reset_ep: flag to reset the endpoint state
1447  *
1448  * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
1449  * For control endpoints, both the input and output sides are handled.
1450  */
usb_enable_endpoint(struct usb_device * dev,struct usb_host_endpoint * ep,bool reset_ep)1451 void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep,
1452 		bool reset_ep)
1453 {
1454 	int epnum = usb_endpoint_num(&ep->desc);
1455 	int is_out = usb_endpoint_dir_out(&ep->desc);
1456 	int is_control = usb_endpoint_xfer_control(&ep->desc);
1457 
1458 	if (reset_ep)
1459 		usb_hcd_reset_endpoint(dev, ep);
1460 	if (is_out || is_control)
1461 		dev->ep_out[epnum] = ep;
1462 	if (!is_out || is_control)
1463 		dev->ep_in[epnum] = ep;
1464 	ep->enabled = 1;
1465 }
1466 
1467 /**
1468  * usb_enable_interface - Enable all the endpoints for an interface
1469  * @dev: the device whose interface is being enabled
1470  * @intf: pointer to the interface descriptor
1471  * @reset_eps: flag to reset the endpoints' state
1472  *
1473  * Enables all the endpoints for the interface's current altsetting.
1474  */
usb_enable_interface(struct usb_device * dev,struct usb_interface * intf,bool reset_eps)1475 void usb_enable_interface(struct usb_device *dev,
1476 		struct usb_interface *intf, bool reset_eps)
1477 {
1478 	struct usb_host_interface *alt = intf->cur_altsetting;
1479 	int i;
1480 
1481 	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1482 		usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps);
1483 }
1484 
1485 /**
1486  * usb_set_interface - Makes a particular alternate setting be current
1487  * @dev: the device whose interface is being updated
1488  * @interface: the interface being updated
1489  * @alternate: the setting being chosen.
1490  *
1491  * Context: task context, might sleep.
1492  *
1493  * This is used to enable data transfers on interfaces that may not
1494  * be enabled by default.  Not all devices support such configurability.
1495  * Only the driver bound to an interface may change its setting.
1496  *
1497  * Within any given configuration, each interface may have several
1498  * alternative settings.  These are often used to control levels of
1499  * bandwidth consumption.  For example, the default setting for a high
1500  * speed interrupt endpoint may not send more than 64 bytes per microframe,
1501  * while interrupt transfers of up to 3KBytes per microframe are legal.
1502  * Also, isochronous endpoints may never be part of an
1503  * interface's default setting.  To access such bandwidth, alternate
1504  * interface settings must be made current.
1505  *
1506  * Note that in the Linux USB subsystem, bandwidth associated with
1507  * an endpoint in a given alternate setting is not reserved until an URB
1508  * is submitted that needs that bandwidth.  Some other operating systems
1509  * allocate bandwidth early, when a configuration is chosen.
1510  *
1511  * xHCI reserves bandwidth and configures the alternate setting in
1512  * usb_hcd_alloc_bandwidth(). If it fails the original interface altsetting
1513  * may be disabled. Drivers cannot rely on any particular alternate
1514  * setting being in effect after a failure.
1515  *
1516  * This call is synchronous, and may not be used in an interrupt context.
1517  * Also, drivers must not change altsettings while urbs are scheduled for
1518  * endpoints in that interface; all such urbs must first be completed
1519  * (perhaps forced by unlinking).
1520  *
1521  * Return: Zero on success, or else the status code returned by the
1522  * underlying usb_control_msg() call.
1523  */
usb_set_interface(struct usb_device * dev,int interface,int alternate)1524 int usb_set_interface(struct usb_device *dev, int interface, int alternate)
1525 {
1526 	struct usb_interface *iface;
1527 	struct usb_host_interface *alt;
1528 	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1529 	int i, ret, manual = 0;
1530 	unsigned int epaddr;
1531 	unsigned int pipe;
1532 
1533 	if (dev->state == USB_STATE_SUSPENDED)
1534 		return -EHOSTUNREACH;
1535 
1536 	iface = usb_ifnum_to_if(dev, interface);
1537 	if (!iface) {
1538 		dev_dbg(&dev->dev, "selecting invalid interface %d\n",
1539 			interface);
1540 		return -EINVAL;
1541 	}
1542 	if (iface->unregistering)
1543 		return -ENODEV;
1544 
1545 	alt = usb_altnum_to_altsetting(iface, alternate);
1546 	if (!alt) {
1547 		dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
1548 			 alternate);
1549 		return -EINVAL;
1550 	}
1551 	/*
1552 	 * usb3 hosts configure the interface in usb_hcd_alloc_bandwidth,
1553 	 * including freeing dropped endpoint ring buffers.
1554 	 * Make sure the interface endpoints are flushed before that
1555 	 */
1556 	usb_disable_interface(dev, iface, false);
1557 
1558 	/* Make sure we have enough bandwidth for this alternate interface.
1559 	 * Remove the current alt setting and add the new alt setting.
1560 	 */
1561 	mutex_lock(hcd->bandwidth_mutex);
1562 	/* Disable LPM, and re-enable it once the new alt setting is installed,
1563 	 * so that the xHCI driver can recalculate the U1/U2 timeouts.
1564 	 */
1565 	if (usb_disable_lpm(dev)) {
1566 		dev_err(&iface->dev, "%s Failed to disable LPM\n", __func__);
1567 		mutex_unlock(hcd->bandwidth_mutex);
1568 		return -ENOMEM;
1569 	}
1570 	/* Changing alt-setting also frees any allocated streams */
1571 	for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
1572 		iface->cur_altsetting->endpoint[i].streams = 0;
1573 
1574 	ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
1575 	if (ret < 0) {
1576 		dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
1577 				alternate);
1578 		usb_enable_lpm(dev);
1579 		mutex_unlock(hcd->bandwidth_mutex);
1580 		return ret;
1581 	}
1582 
1583 	if (dev->quirks & USB_QUIRK_NO_SET_INTF)
1584 		ret = -EPIPE;
1585 	else
1586 		ret = usb_control_msg_send(dev, 0,
1587 					   USB_REQ_SET_INTERFACE,
1588 					   USB_RECIP_INTERFACE, alternate,
1589 					   interface, NULL, 0, 5000,
1590 					   GFP_NOIO);
1591 
1592 	/* 9.4.10 says devices don't need this and are free to STALL the
1593 	 * request if the interface only has one alternate setting.
1594 	 */
1595 	if (ret == -EPIPE && iface->num_altsetting == 1) {
1596 		dev_dbg(&dev->dev,
1597 			"manual set_interface for iface %d, alt %d\n",
1598 			interface, alternate);
1599 		manual = 1;
1600 	} else if (ret) {
1601 		/* Re-instate the old alt setting */
1602 		usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
1603 		usb_enable_lpm(dev);
1604 		mutex_unlock(hcd->bandwidth_mutex);
1605 		return ret;
1606 	}
1607 	mutex_unlock(hcd->bandwidth_mutex);
1608 
1609 	/* FIXME drivers shouldn't need to replicate/bugfix the logic here
1610 	 * when they implement async or easily-killable versions of this or
1611 	 * other "should-be-internal" functions (like clear_halt).
1612 	 * should hcd+usbcore postprocess control requests?
1613 	 */
1614 
1615 	/* prevent submissions using previous endpoint settings */
1616 	if (iface->cur_altsetting != alt) {
1617 		remove_intf_ep_devs(iface);
1618 		usb_remove_sysfs_intf_files(iface);
1619 	}
1620 	usb_disable_interface(dev, iface, true);
1621 
1622 	iface->cur_altsetting = alt;
1623 
1624 	/* Now that the interface is installed, re-enable LPM. */
1625 	usb_unlocked_enable_lpm(dev);
1626 
1627 	/* If the interface only has one altsetting and the device didn't
1628 	 * accept the request, we attempt to carry out the equivalent action
1629 	 * by manually clearing the HALT feature for each endpoint in the
1630 	 * new altsetting.
1631 	 */
1632 	if (manual) {
1633 		for (i = 0; i < alt->desc.bNumEndpoints; i++) {
1634 			epaddr = alt->endpoint[i].desc.bEndpointAddress;
1635 			pipe = __create_pipe(dev,
1636 					USB_ENDPOINT_NUMBER_MASK & epaddr) |
1637 					(usb_endpoint_out(epaddr) ?
1638 					USB_DIR_OUT : USB_DIR_IN);
1639 
1640 			usb_clear_halt(dev, pipe);
1641 		}
1642 	}
1643 
1644 	/* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1645 	 *
1646 	 * Note:
1647 	 * Despite EP0 is always present in all interfaces/AS, the list of
1648 	 * endpoints from the descriptor does not contain EP0. Due to its
1649 	 * omnipresence one might expect EP0 being considered "affected" by
1650 	 * any SetInterface request and hence assume toggles need to be reset.
1651 	 * However, EP0 toggles are re-synced for every individual transfer
1652 	 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1653 	 * (Likewise, EP0 never "halts" on well designed devices.)
1654 	 */
1655 	usb_enable_interface(dev, iface, true);
1656 	if (device_is_registered(&iface->dev)) {
1657 		usb_create_sysfs_intf_files(iface);
1658 		create_intf_ep_devs(iface);
1659 	}
1660 	return 0;
1661 }
1662 EXPORT_SYMBOL_GPL(usb_set_interface);
1663 
1664 /**
1665  * usb_reset_configuration - lightweight device reset
1666  * @dev: the device whose configuration is being reset
1667  *
1668  * This issues a standard SET_CONFIGURATION request to the device using
1669  * the current configuration.  The effect is to reset most USB-related
1670  * state in the device, including interface altsettings (reset to zero),
1671  * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
1672  * endpoints).  Other usbcore state is unchanged, including bindings of
1673  * usb device drivers to interfaces.
1674  *
1675  * Because this affects multiple interfaces, avoid using this with composite
1676  * (multi-interface) devices.  Instead, the driver for each interface may
1677  * use usb_set_interface() on the interfaces it claims.  Be careful though;
1678  * some devices don't support the SET_INTERFACE request, and others won't
1679  * reset all the interface state (notably endpoint state).  Resetting the whole
1680  * configuration would affect other drivers' interfaces.
1681  *
1682  * The caller must own the device lock.
1683  *
1684  * Return: Zero on success, else a negative error code.
1685  *
1686  * If this routine fails the device will probably be in an unusable state
1687  * with endpoints disabled, and interfaces only partially enabled.
1688  */
usb_reset_configuration(struct usb_device * dev)1689 int usb_reset_configuration(struct usb_device *dev)
1690 {
1691 	int			i, retval;
1692 	struct usb_host_config	*config;
1693 	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1694 
1695 	if (dev->state == USB_STATE_SUSPENDED)
1696 		return -EHOSTUNREACH;
1697 
1698 	/* caller must have locked the device and must own
1699 	 * the usb bus readlock (so driver bindings are stable);
1700 	 * calls during probe() are fine
1701 	 */
1702 
1703 	usb_disable_device_endpoints(dev, 1); /* skip ep0*/
1704 
1705 	config = dev->actconfig;
1706 	retval = 0;
1707 	mutex_lock(hcd->bandwidth_mutex);
1708 	/* Disable LPM, and re-enable it once the configuration is reset, so
1709 	 * that the xHCI driver can recalculate the U1/U2 timeouts.
1710 	 */
1711 	if (usb_disable_lpm(dev)) {
1712 		dev_err(&dev->dev, "%s Failed to disable LPM\n", __func__);
1713 		mutex_unlock(hcd->bandwidth_mutex);
1714 		return -ENOMEM;
1715 	}
1716 
1717 	/* xHCI adds all endpoints in usb_hcd_alloc_bandwidth */
1718 	retval = usb_hcd_alloc_bandwidth(dev, config, NULL, NULL);
1719 	if (retval < 0) {
1720 		usb_enable_lpm(dev);
1721 		mutex_unlock(hcd->bandwidth_mutex);
1722 		return retval;
1723 	}
1724 	retval = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
1725 				      config->desc.bConfigurationValue, 0,
1726 				      NULL, 0, USB_CTRL_SET_TIMEOUT,
1727 				      GFP_NOIO);
1728 	if (retval) {
1729 		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1730 		usb_enable_lpm(dev);
1731 		mutex_unlock(hcd->bandwidth_mutex);
1732 		return retval;
1733 	}
1734 	mutex_unlock(hcd->bandwidth_mutex);
1735 
1736 	/* re-init hc/hcd interface/endpoint state */
1737 	for (i = 0; i < config->desc.bNumInterfaces; i++) {
1738 		struct usb_interface *intf = config->interface[i];
1739 		struct usb_host_interface *alt;
1740 
1741 		alt = usb_altnum_to_altsetting(intf, 0);
1742 
1743 		/* No altsetting 0?  We'll assume the first altsetting.
1744 		 * We could use a GetInterface call, but if a device is
1745 		 * so non-compliant that it doesn't have altsetting 0
1746 		 * then I wouldn't trust its reply anyway.
1747 		 */
1748 		if (!alt)
1749 			alt = &intf->altsetting[0];
1750 
1751 		if (alt != intf->cur_altsetting) {
1752 			remove_intf_ep_devs(intf);
1753 			usb_remove_sysfs_intf_files(intf);
1754 		}
1755 		intf->cur_altsetting = alt;
1756 		usb_enable_interface(dev, intf, true);
1757 		if (device_is_registered(&intf->dev)) {
1758 			usb_create_sysfs_intf_files(intf);
1759 			create_intf_ep_devs(intf);
1760 		}
1761 	}
1762 	/* Now that the interfaces are installed, re-enable LPM. */
1763 	usb_unlocked_enable_lpm(dev);
1764 	return 0;
1765 }
1766 EXPORT_SYMBOL_GPL(usb_reset_configuration);
1767 
usb_release_interface(struct device * dev)1768 static void usb_release_interface(struct device *dev)
1769 {
1770 	struct usb_interface *intf = to_usb_interface(dev);
1771 	struct usb_interface_cache *intfc =
1772 			altsetting_to_usb_interface_cache(intf->altsetting);
1773 
1774 	kref_put(&intfc->ref, usb_release_interface_cache);
1775 	usb_put_dev(interface_to_usbdev(intf));
1776 	of_node_put(dev->of_node);
1777 	kfree(intf);
1778 }
1779 
1780 /*
1781  * usb_deauthorize_interface - deauthorize an USB interface
1782  *
1783  * @intf: USB interface structure
1784  */
usb_deauthorize_interface(struct usb_interface * intf)1785 void usb_deauthorize_interface(struct usb_interface *intf)
1786 {
1787 	struct device *dev = &intf->dev;
1788 
1789 	device_lock(dev->parent);
1790 
1791 	if (intf->authorized) {
1792 		device_lock(dev);
1793 		intf->authorized = 0;
1794 		device_unlock(dev);
1795 
1796 		usb_forced_unbind_intf(intf);
1797 	}
1798 
1799 	device_unlock(dev->parent);
1800 }
1801 
1802 /*
1803  * usb_authorize_interface - authorize an USB interface
1804  *
1805  * @intf: USB interface structure
1806  */
usb_authorize_interface(struct usb_interface * intf)1807 void usb_authorize_interface(struct usb_interface *intf)
1808 {
1809 	struct device *dev = &intf->dev;
1810 
1811 	if (!intf->authorized) {
1812 		device_lock(dev);
1813 		intf->authorized = 1; /* authorize interface */
1814 		device_unlock(dev);
1815 	}
1816 }
1817 
usb_if_uevent(const struct device * dev,struct kobj_uevent_env * env)1818 static int usb_if_uevent(const struct device *dev, struct kobj_uevent_env *env)
1819 {
1820 	const struct usb_device *usb_dev;
1821 	const struct usb_interface *intf;
1822 	const struct usb_host_interface *alt;
1823 
1824 	intf = to_usb_interface(dev);
1825 	usb_dev = interface_to_usbdev(intf);
1826 	alt = intf->cur_altsetting;
1827 
1828 	if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
1829 		   alt->desc.bInterfaceClass,
1830 		   alt->desc.bInterfaceSubClass,
1831 		   alt->desc.bInterfaceProtocol))
1832 		return -ENOMEM;
1833 
1834 	if (add_uevent_var(env,
1835 		   "MODALIAS=usb:"
1836 		   "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X",
1837 		   le16_to_cpu(usb_dev->descriptor.idVendor),
1838 		   le16_to_cpu(usb_dev->descriptor.idProduct),
1839 		   le16_to_cpu(usb_dev->descriptor.bcdDevice),
1840 		   usb_dev->descriptor.bDeviceClass,
1841 		   usb_dev->descriptor.bDeviceSubClass,
1842 		   usb_dev->descriptor.bDeviceProtocol,
1843 		   alt->desc.bInterfaceClass,
1844 		   alt->desc.bInterfaceSubClass,
1845 		   alt->desc.bInterfaceProtocol,
1846 		   alt->desc.bInterfaceNumber))
1847 		return -ENOMEM;
1848 
1849 	return 0;
1850 }
1851 
1852 struct device_type usb_if_device_type = {
1853 	.name =		"usb_interface",
1854 	.release =	usb_release_interface,
1855 	.uevent =	usb_if_uevent,
1856 };
1857 
find_iad(struct usb_device * dev,struct usb_host_config * config,u8 inum)1858 static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
1859 						struct usb_host_config *config,
1860 						u8 inum)
1861 {
1862 	struct usb_interface_assoc_descriptor *retval = NULL;
1863 	struct usb_interface_assoc_descriptor *intf_assoc;
1864 	int first_intf;
1865 	int last_intf;
1866 	int i;
1867 
1868 	for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
1869 		intf_assoc = config->intf_assoc[i];
1870 		if (intf_assoc->bInterfaceCount == 0)
1871 			continue;
1872 
1873 		first_intf = intf_assoc->bFirstInterface;
1874 		last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
1875 		if (inum >= first_intf && inum <= last_intf) {
1876 			if (!retval)
1877 				retval = intf_assoc;
1878 			else
1879 				dev_err(&dev->dev, "Interface #%d referenced"
1880 					" by multiple IADs\n", inum);
1881 		}
1882 	}
1883 
1884 	return retval;
1885 }
1886 
1887 
1888 /*
1889  * Internal function to queue a device reset
1890  * See usb_queue_reset_device() for more details
1891  */
__usb_queue_reset_device(struct work_struct * ws)1892 static void __usb_queue_reset_device(struct work_struct *ws)
1893 {
1894 	int rc;
1895 	struct usb_interface *iface =
1896 		container_of(ws, struct usb_interface, reset_ws);
1897 	struct usb_device *udev = interface_to_usbdev(iface);
1898 
1899 	rc = usb_lock_device_for_reset(udev, iface);
1900 	if (rc >= 0) {
1901 		usb_reset_device(udev);
1902 		usb_unlock_device(udev);
1903 	}
1904 	usb_put_intf(iface);	/* Undo _get_ in usb_queue_reset_device() */
1905 }
1906 
1907 /*
1908  * Internal function to set the wireless_status sysfs attribute
1909  * See usb_set_wireless_status() for more details
1910  */
__usb_wireless_status_intf(struct work_struct * ws)1911 static void __usb_wireless_status_intf(struct work_struct *ws)
1912 {
1913 	struct usb_interface *iface =
1914 		container_of(ws, struct usb_interface, wireless_status_work);
1915 
1916 	device_lock(iface->dev.parent);
1917 	if (iface->sysfs_files_created)
1918 		usb_update_wireless_status_attr(iface);
1919 	device_unlock(iface->dev.parent);
1920 	usb_put_intf(iface);	/* Undo _get_ in usb_set_wireless_status() */
1921 }
1922 
1923 /**
1924  * usb_set_wireless_status - sets the wireless_status struct member
1925  * @iface: the interface to modify
1926  * @status: the new wireless status
1927  *
1928  * Set the wireless_status struct member to the new value, and emit
1929  * sysfs changes as necessary.
1930  *
1931  * Returns: 0 on success, -EALREADY if already set.
1932  */
usb_set_wireless_status(struct usb_interface * iface,enum usb_wireless_status status)1933 int usb_set_wireless_status(struct usb_interface *iface,
1934 		enum usb_wireless_status status)
1935 {
1936 	if (iface->wireless_status == status)
1937 		return -EALREADY;
1938 
1939 	usb_get_intf(iface);
1940 	iface->wireless_status = status;
1941 	schedule_work(&iface->wireless_status_work);
1942 
1943 	return 0;
1944 }
1945 EXPORT_SYMBOL_GPL(usb_set_wireless_status);
1946 
1947 /*
1948  * usb_set_configuration - Makes a particular device setting be current
1949  * @dev: the device whose configuration is being updated
1950  * @configuration: the configuration being chosen.
1951  *
1952  * Context: task context, might sleep. Caller holds device lock.
1953  *
1954  * This is used to enable non-default device modes.  Not all devices
1955  * use this kind of configurability; many devices only have one
1956  * configuration.
1957  *
1958  * @configuration is the value of the configuration to be installed.
1959  * According to the USB spec (e.g. section 9.1.1.5), configuration values
1960  * must be non-zero; a value of zero indicates that the device in
1961  * unconfigured.  However some devices erroneously use 0 as one of their
1962  * configuration values.  To help manage such devices, this routine will
1963  * accept @configuration = -1 as indicating the device should be put in
1964  * an unconfigured state.
1965  *
1966  * USB device configurations may affect Linux interoperability,
1967  * power consumption and the functionality available.  For example,
1968  * the default configuration is limited to using 100mA of bus power,
1969  * so that when certain device functionality requires more power,
1970  * and the device is bus powered, that functionality should be in some
1971  * non-default device configuration.  Other device modes may also be
1972  * reflected as configuration options, such as whether two ISDN
1973  * channels are available independently; and choosing between open
1974  * standard device protocols (like CDC) or proprietary ones.
1975  *
1976  * Note that a non-authorized device (dev->authorized == 0) will only
1977  * be put in unconfigured mode.
1978  *
1979  * Note that USB has an additional level of device configurability,
1980  * associated with interfaces.  That configurability is accessed using
1981  * usb_set_interface().
1982  *
1983  * This call is synchronous. The calling context must be able to sleep,
1984  * must own the device lock, and must not hold the driver model's USB
1985  * bus mutex; usb interface driver probe() methods cannot use this routine.
1986  *
1987  * Returns zero on success, or else the status code returned by the
1988  * underlying call that failed.  On successful completion, each interface
1989  * in the original device configuration has been destroyed, and each one
1990  * in the new configuration has been probed by all relevant usb device
1991  * drivers currently known to the kernel.
1992  */
usb_set_configuration(struct usb_device * dev,int configuration)1993 int usb_set_configuration(struct usb_device *dev, int configuration)
1994 {
1995 	int i, ret;
1996 	struct usb_host_config *cp = NULL;
1997 	struct usb_interface **new_interfaces = NULL;
1998 	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1999 	int n, nintf;
2000 
2001 	if (dev->authorized == 0 || configuration == -1)
2002 		configuration = 0;
2003 	else {
2004 		for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
2005 			if (dev->config[i].desc.bConfigurationValue ==
2006 					configuration) {
2007 				cp = &dev->config[i];
2008 				break;
2009 			}
2010 		}
2011 	}
2012 	if ((!cp && configuration != 0))
2013 		return -EINVAL;
2014 
2015 	/* The USB spec says configuration 0 means unconfigured.
2016 	 * But if a device includes a configuration numbered 0,
2017 	 * we will accept it as a correctly configured state.
2018 	 * Use -1 if you really want to unconfigure the device.
2019 	 */
2020 	if (cp && configuration == 0)
2021 		dev_warn(&dev->dev, "config 0 descriptor??\n");
2022 
2023 	/* Allocate memory for new interfaces before doing anything else,
2024 	 * so that if we run out then nothing will have changed. */
2025 	n = nintf = 0;
2026 	if (cp) {
2027 		nintf = cp->desc.bNumInterfaces;
2028 		new_interfaces = kmalloc_array(nintf, sizeof(*new_interfaces),
2029 					       GFP_NOIO);
2030 		if (!new_interfaces)
2031 			return -ENOMEM;
2032 
2033 		for (; n < nintf; ++n) {
2034 			new_interfaces[n] = kzalloc(
2035 					sizeof(struct usb_interface),
2036 					GFP_NOIO);
2037 			if (!new_interfaces[n]) {
2038 				ret = -ENOMEM;
2039 free_interfaces:
2040 				while (--n >= 0)
2041 					kfree(new_interfaces[n]);
2042 				kfree(new_interfaces);
2043 				return ret;
2044 			}
2045 		}
2046 
2047 		i = dev->bus_mA - usb_get_max_power(dev, cp);
2048 		if (i < 0)
2049 			dev_warn(&dev->dev, "new config #%d exceeds power "
2050 					"limit by %dmA\n",
2051 					configuration, -i);
2052 	}
2053 
2054 	/* Wake up the device so we can send it the Set-Config request */
2055 	ret = usb_autoresume_device(dev);
2056 	if (ret)
2057 		goto free_interfaces;
2058 
2059 	/* if it's already configured, clear out old state first.
2060 	 * getting rid of old interfaces means unbinding their drivers.
2061 	 */
2062 	if (dev->state != USB_STATE_ADDRESS)
2063 		usb_disable_device(dev, 1);	/* Skip ep0 */
2064 
2065 	/* Get rid of pending async Set-Config requests for this device */
2066 	cancel_async_set_config(dev);
2067 
2068 	/* Make sure we have bandwidth (and available HCD resources) for this
2069 	 * configuration.  Remove endpoints from the schedule if we're dropping
2070 	 * this configuration to set configuration 0.  After this point, the
2071 	 * host controller will not allow submissions to dropped endpoints.  If
2072 	 * this call fails, the device state is unchanged.
2073 	 */
2074 	mutex_lock(hcd->bandwidth_mutex);
2075 	/* Disable LPM, and re-enable it once the new configuration is
2076 	 * installed, so that the xHCI driver can recalculate the U1/U2
2077 	 * timeouts.
2078 	 */
2079 	if (dev->actconfig && usb_disable_lpm(dev)) {
2080 		dev_err(&dev->dev, "%s Failed to disable LPM\n", __func__);
2081 		mutex_unlock(hcd->bandwidth_mutex);
2082 		ret = -ENOMEM;
2083 		goto free_interfaces;
2084 	}
2085 	ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
2086 	if (ret < 0) {
2087 		if (dev->actconfig)
2088 			usb_enable_lpm(dev);
2089 		mutex_unlock(hcd->bandwidth_mutex);
2090 		usb_autosuspend_device(dev);
2091 		goto free_interfaces;
2092 	}
2093 
2094 	/*
2095 	 * Initialize the new interface structures and the
2096 	 * hc/hcd/usbcore interface/endpoint state.
2097 	 */
2098 	for (i = 0; i < nintf; ++i) {
2099 		struct usb_interface_cache *intfc;
2100 		struct usb_interface *intf;
2101 		struct usb_host_interface *alt;
2102 		u8 ifnum;
2103 
2104 		cp->interface[i] = intf = new_interfaces[i];
2105 		intfc = cp->intf_cache[i];
2106 		intf->altsetting = intfc->altsetting;
2107 		intf->num_altsetting = intfc->num_altsetting;
2108 		intf->authorized = !!HCD_INTF_AUTHORIZED(hcd);
2109 		kref_get(&intfc->ref);
2110 
2111 		alt = usb_altnum_to_altsetting(intf, 0);
2112 
2113 		/* No altsetting 0?  We'll assume the first altsetting.
2114 		 * We could use a GetInterface call, but if a device is
2115 		 * so non-compliant that it doesn't have altsetting 0
2116 		 * then I wouldn't trust its reply anyway.
2117 		 */
2118 		if (!alt)
2119 			alt = &intf->altsetting[0];
2120 
2121 		ifnum = alt->desc.bInterfaceNumber;
2122 		intf->intf_assoc = find_iad(dev, cp, ifnum);
2123 		intf->cur_altsetting = alt;
2124 		usb_enable_interface(dev, intf, true);
2125 		intf->dev.parent = &dev->dev;
2126 		if (usb_of_has_combined_node(dev)) {
2127 			device_set_of_node_from_dev(&intf->dev, &dev->dev);
2128 		} else {
2129 			intf->dev.of_node = usb_of_get_interface_node(dev,
2130 					configuration, ifnum);
2131 		}
2132 		ACPI_COMPANION_SET(&intf->dev, ACPI_COMPANION(&dev->dev));
2133 		intf->dev.driver = NULL;
2134 		intf->dev.bus = &usb_bus_type;
2135 		intf->dev.type = &usb_if_device_type;
2136 		intf->dev.groups = usb_interface_groups;
2137 		INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
2138 		INIT_WORK(&intf->wireless_status_work, __usb_wireless_status_intf);
2139 		intf->minor = -1;
2140 		device_initialize(&intf->dev);
2141 		pm_runtime_no_callbacks(&intf->dev);
2142 		dev_set_name(&intf->dev, "%d-%s:%d.%d", dev->bus->busnum,
2143 				dev->devpath, configuration, ifnum);
2144 		usb_get_dev(dev);
2145 	}
2146 	kfree(new_interfaces);
2147 
2148 	ret = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
2149 				   configuration, 0, NULL, 0,
2150 				   USB_CTRL_SET_TIMEOUT, GFP_NOIO);
2151 	if (ret && cp) {
2152 		/*
2153 		 * All the old state is gone, so what else can we do?
2154 		 * The device is probably useless now anyway.
2155 		 */
2156 		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
2157 		for (i = 0; i < nintf; ++i) {
2158 			usb_disable_interface(dev, cp->interface[i], true);
2159 			put_device(&cp->interface[i]->dev);
2160 			cp->interface[i] = NULL;
2161 		}
2162 		cp = NULL;
2163 	}
2164 
2165 	dev->actconfig = cp;
2166 	mutex_unlock(hcd->bandwidth_mutex);
2167 
2168 	if (!cp) {
2169 		usb_set_device_state(dev, USB_STATE_ADDRESS);
2170 
2171 		/* Leave LPM disabled while the device is unconfigured. */
2172 		usb_autosuspend_device(dev);
2173 		return ret;
2174 	}
2175 	usb_set_device_state(dev, USB_STATE_CONFIGURED);
2176 
2177 	if (cp->string == NULL &&
2178 			!(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
2179 		cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
2180 
2181 	/* Now that the interfaces are installed, re-enable LPM. */
2182 	usb_unlocked_enable_lpm(dev);
2183 	/* Enable LTM if it was turned off by usb_disable_device. */
2184 	usb_enable_ltm(dev);
2185 
2186 	/* Now that all the interfaces are set up, register them
2187 	 * to trigger binding of drivers to interfaces.  probe()
2188 	 * routines may install different altsettings and may
2189 	 * claim() any interfaces not yet bound.  Many class drivers
2190 	 * need that: CDC, audio, video, etc.
2191 	 */
2192 	for (i = 0; i < nintf; ++i) {
2193 		struct usb_interface *intf = cp->interface[i];
2194 
2195 		if (intf->dev.of_node &&
2196 		    !of_device_is_available(intf->dev.of_node)) {
2197 			dev_info(&dev->dev, "skipping disabled interface %d\n",
2198 				 intf->cur_altsetting->desc.bInterfaceNumber);
2199 			continue;
2200 		}
2201 
2202 		dev_dbg(&dev->dev,
2203 			"adding %s (config #%d, interface %d)\n",
2204 			dev_name(&intf->dev), configuration,
2205 			intf->cur_altsetting->desc.bInterfaceNumber);
2206 		device_enable_async_suspend(&intf->dev);
2207 		ret = device_add(&intf->dev);
2208 		if (ret != 0) {
2209 			dev_err(&dev->dev, "device_add(%s) --> %d\n",
2210 				dev_name(&intf->dev), ret);
2211 			continue;
2212 		}
2213 		create_intf_ep_devs(intf);
2214 	}
2215 
2216 	usb_autosuspend_device(dev);
2217 	return 0;
2218 }
2219 EXPORT_SYMBOL_GPL(usb_set_configuration);
2220 
2221 static LIST_HEAD(set_config_list);
2222 static DEFINE_SPINLOCK(set_config_lock);
2223 
2224 struct set_config_request {
2225 	struct usb_device	*udev;
2226 	int			config;
2227 	struct work_struct	work;
2228 	struct list_head	node;
2229 };
2230 
2231 /* Worker routine for usb_driver_set_configuration() */
driver_set_config_work(struct work_struct * work)2232 static void driver_set_config_work(struct work_struct *work)
2233 {
2234 	struct set_config_request *req =
2235 		container_of(work, struct set_config_request, work);
2236 	struct usb_device *udev = req->udev;
2237 
2238 	usb_lock_device(udev);
2239 	spin_lock(&set_config_lock);
2240 	list_del(&req->node);
2241 	spin_unlock(&set_config_lock);
2242 
2243 	if (req->config >= -1)		/* Is req still valid? */
2244 		usb_set_configuration(udev, req->config);
2245 	usb_unlock_device(udev);
2246 	usb_put_dev(udev);
2247 	kfree(req);
2248 }
2249 
2250 /* Cancel pending Set-Config requests for a device whose configuration
2251  * was just changed
2252  */
cancel_async_set_config(struct usb_device * udev)2253 static void cancel_async_set_config(struct usb_device *udev)
2254 {
2255 	struct set_config_request *req;
2256 
2257 	spin_lock(&set_config_lock);
2258 	list_for_each_entry(req, &set_config_list, node) {
2259 		if (req->udev == udev)
2260 			req->config = -999;	/* Mark as cancelled */
2261 	}
2262 	spin_unlock(&set_config_lock);
2263 }
2264 
2265 /**
2266  * usb_driver_set_configuration - Provide a way for drivers to change device configurations
2267  * @udev: the device whose configuration is being updated
2268  * @config: the configuration being chosen.
2269  * Context: In process context, must be able to sleep
2270  *
2271  * Device interface drivers are not allowed to change device configurations.
2272  * This is because changing configurations will destroy the interface the
2273  * driver is bound to and create new ones; it would be like a floppy-disk
2274  * driver telling the computer to replace the floppy-disk drive with a
2275  * tape drive!
2276  *
2277  * Still, in certain specialized circumstances the need may arise.  This
2278  * routine gets around the normal restrictions by using a work thread to
2279  * submit the change-config request.
2280  *
2281  * Return: 0 if the request was successfully queued, error code otherwise.
2282  * The caller has no way to know whether the queued request will eventually
2283  * succeed.
2284  */
usb_driver_set_configuration(struct usb_device * udev,int config)2285 int usb_driver_set_configuration(struct usb_device *udev, int config)
2286 {
2287 	struct set_config_request *req;
2288 
2289 	req = kmalloc(sizeof(*req), GFP_KERNEL);
2290 	if (!req)
2291 		return -ENOMEM;
2292 	req->udev = udev;
2293 	req->config = config;
2294 	INIT_WORK(&req->work, driver_set_config_work);
2295 
2296 	spin_lock(&set_config_lock);
2297 	list_add(&req->node, &set_config_list);
2298 	spin_unlock(&set_config_lock);
2299 
2300 	usb_get_dev(udev);
2301 	schedule_work(&req->work);
2302 	return 0;
2303 }
2304 EXPORT_SYMBOL_GPL(usb_driver_set_configuration);
2305 
2306 /**
2307  * cdc_parse_cdc_header - parse the extra headers present in CDC devices
2308  * @hdr: the place to put the results of the parsing
2309  * @intf: the interface for which parsing is requested
2310  * @buffer: pointer to the extra headers to be parsed
2311  * @buflen: length of the extra headers
2312  *
2313  * This evaluates the extra headers present in CDC devices which
2314  * bind the interfaces for data and control and provide details
2315  * about the capabilities of the device.
2316  *
2317  * Return: number of descriptors parsed or -EINVAL
2318  * if the header is contradictory beyond salvage
2319  */
2320 
cdc_parse_cdc_header(struct usb_cdc_parsed_header * hdr,struct usb_interface * intf,u8 * buffer,int buflen)2321 int cdc_parse_cdc_header(struct usb_cdc_parsed_header *hdr,
2322 				struct usb_interface *intf,
2323 				u8 *buffer,
2324 				int buflen)
2325 {
2326 	/* duplicates are ignored */
2327 	struct usb_cdc_union_desc *union_header = NULL;
2328 
2329 	/* duplicates are not tolerated */
2330 	struct usb_cdc_header_desc *header = NULL;
2331 	struct usb_cdc_ether_desc *ether = NULL;
2332 	struct usb_cdc_mdlm_detail_desc *detail = NULL;
2333 	struct usb_cdc_mdlm_desc *desc = NULL;
2334 
2335 	unsigned int elength;
2336 	int cnt = 0;
2337 
2338 	memset(hdr, 0x00, sizeof(struct usb_cdc_parsed_header));
2339 	hdr->phonet_magic_present = false;
2340 	while (buflen > 0) {
2341 		elength = buffer[0];
2342 		if (!elength) {
2343 			dev_err(&intf->dev, "skipping garbage byte\n");
2344 			elength = 1;
2345 			goto next_desc;
2346 		}
2347 		if ((buflen < elength) || (elength < 3)) {
2348 			dev_err(&intf->dev, "invalid descriptor buffer length\n");
2349 			break;
2350 		}
2351 		if (buffer[1] != USB_DT_CS_INTERFACE) {
2352 			dev_err(&intf->dev, "skipping garbage\n");
2353 			goto next_desc;
2354 		}
2355 
2356 		switch (buffer[2]) {
2357 		case USB_CDC_UNION_TYPE: /* we've found it */
2358 			if (elength < sizeof(struct usb_cdc_union_desc))
2359 				goto next_desc;
2360 			if (union_header) {
2361 				dev_err(&intf->dev, "More than one union descriptor, skipping ...\n");
2362 				goto next_desc;
2363 			}
2364 			union_header = (struct usb_cdc_union_desc *)buffer;
2365 			break;
2366 		case USB_CDC_COUNTRY_TYPE:
2367 			if (elength < sizeof(struct usb_cdc_country_functional_desc))
2368 				goto next_desc;
2369 			hdr->usb_cdc_country_functional_desc =
2370 				(struct usb_cdc_country_functional_desc *)buffer;
2371 			break;
2372 		case USB_CDC_HEADER_TYPE:
2373 			if (elength != sizeof(struct usb_cdc_header_desc))
2374 				goto next_desc;
2375 			if (header)
2376 				return -EINVAL;
2377 			header = (struct usb_cdc_header_desc *)buffer;
2378 			break;
2379 		case USB_CDC_ACM_TYPE:
2380 			if (elength < sizeof(struct usb_cdc_acm_descriptor))
2381 				goto next_desc;
2382 			hdr->usb_cdc_acm_descriptor =
2383 				(struct usb_cdc_acm_descriptor *)buffer;
2384 			break;
2385 		case USB_CDC_ETHERNET_TYPE:
2386 			if (elength != sizeof(struct usb_cdc_ether_desc))
2387 				goto next_desc;
2388 			if (ether)
2389 				return -EINVAL;
2390 			ether = (struct usb_cdc_ether_desc *)buffer;
2391 			break;
2392 		case USB_CDC_CALL_MANAGEMENT_TYPE:
2393 			if (elength < sizeof(struct usb_cdc_call_mgmt_descriptor))
2394 				goto next_desc;
2395 			hdr->usb_cdc_call_mgmt_descriptor =
2396 				(struct usb_cdc_call_mgmt_descriptor *)buffer;
2397 			break;
2398 		case USB_CDC_DMM_TYPE:
2399 			if (elength < sizeof(struct usb_cdc_dmm_desc))
2400 				goto next_desc;
2401 			hdr->usb_cdc_dmm_desc =
2402 				(struct usb_cdc_dmm_desc *)buffer;
2403 			break;
2404 		case USB_CDC_MDLM_TYPE:
2405 			if (elength < sizeof(struct usb_cdc_mdlm_desc))
2406 				goto next_desc;
2407 			if (desc)
2408 				return -EINVAL;
2409 			desc = (struct usb_cdc_mdlm_desc *)buffer;
2410 			break;
2411 		case USB_CDC_MDLM_DETAIL_TYPE:
2412 			if (elength < sizeof(struct usb_cdc_mdlm_detail_desc))
2413 				goto next_desc;
2414 			if (detail)
2415 				return -EINVAL;
2416 			detail = (struct usb_cdc_mdlm_detail_desc *)buffer;
2417 			break;
2418 		case USB_CDC_NCM_TYPE:
2419 			if (elength < sizeof(struct usb_cdc_ncm_desc))
2420 				goto next_desc;
2421 			hdr->usb_cdc_ncm_desc = (struct usb_cdc_ncm_desc *)buffer;
2422 			break;
2423 		case USB_CDC_MBIM_TYPE:
2424 			if (elength < sizeof(struct usb_cdc_mbim_desc))
2425 				goto next_desc;
2426 
2427 			hdr->usb_cdc_mbim_desc = (struct usb_cdc_mbim_desc *)buffer;
2428 			break;
2429 		case USB_CDC_MBIM_EXTENDED_TYPE:
2430 			if (elength < sizeof(struct usb_cdc_mbim_extended_desc))
2431 				break;
2432 			hdr->usb_cdc_mbim_extended_desc =
2433 				(struct usb_cdc_mbim_extended_desc *)buffer;
2434 			break;
2435 		case CDC_PHONET_MAGIC_NUMBER:
2436 			hdr->phonet_magic_present = true;
2437 			break;
2438 		default:
2439 			/*
2440 			 * there are LOTS more CDC descriptors that
2441 			 * could legitimately be found here.
2442 			 */
2443 			dev_dbg(&intf->dev, "Ignoring descriptor: type %02x, length %ud\n",
2444 					buffer[2], elength);
2445 			goto next_desc;
2446 		}
2447 		cnt++;
2448 next_desc:
2449 		buflen -= elength;
2450 		buffer += elength;
2451 	}
2452 	hdr->usb_cdc_union_desc = union_header;
2453 	hdr->usb_cdc_header_desc = header;
2454 	hdr->usb_cdc_mdlm_detail_desc = detail;
2455 	hdr->usb_cdc_mdlm_desc = desc;
2456 	hdr->usb_cdc_ether_desc = ether;
2457 	return cnt;
2458 }
2459 
2460 EXPORT_SYMBOL(cdc_parse_cdc_header);
2461