xref: /openbmc/linux/drivers/usb/core/config.c (revision a06c488d)
1 #include <linux/usb.h>
2 #include <linux/usb/ch9.h>
3 #include <linux/usb/hcd.h>
4 #include <linux/usb/quirks.h>
5 #include <linux/module.h>
6 #include <linux/slab.h>
7 #include <linux/device.h>
8 #include <asm/byteorder.h>
9 #include "usb.h"
10 
11 
12 #define USB_MAXALTSETTING		128	/* Hard limit */
13 
14 #define USB_MAXCONFIG			8	/* Arbitrary limit */
15 
16 
17 static inline const char *plural(int n)
18 {
19 	return (n == 1 ? "" : "s");
20 }
21 
22 static int find_next_descriptor(unsigned char *buffer, int size,
23     int dt1, int dt2, int *num_skipped)
24 {
25 	struct usb_descriptor_header *h;
26 	int n = 0;
27 	unsigned char *buffer0 = buffer;
28 
29 	/* Find the next descriptor of type dt1 or dt2 */
30 	while (size > 0) {
31 		h = (struct usb_descriptor_header *) buffer;
32 		if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
33 			break;
34 		buffer += h->bLength;
35 		size -= h->bLength;
36 		++n;
37 	}
38 
39 	/* Store the number of descriptors skipped and return the
40 	 * number of bytes skipped */
41 	if (num_skipped)
42 		*num_skipped = n;
43 	return buffer - buffer0;
44 }
45 
46 static void usb_parse_ss_endpoint_companion(struct device *ddev, int cfgno,
47 		int inum, int asnum, struct usb_host_endpoint *ep,
48 		unsigned char *buffer, int size)
49 {
50 	struct usb_ss_ep_comp_descriptor *desc;
51 	int max_tx;
52 
53 	/* The SuperSpeed endpoint companion descriptor is supposed to
54 	 * be the first thing immediately following the endpoint descriptor.
55 	 */
56 	desc = (struct usb_ss_ep_comp_descriptor *) buffer;
57 	if (desc->bDescriptorType != USB_DT_SS_ENDPOINT_COMP ||
58 			size < USB_DT_SS_EP_COMP_SIZE) {
59 		dev_warn(ddev, "No SuperSpeed endpoint companion for config %d "
60 				" interface %d altsetting %d ep %d: "
61 				"using minimum values\n",
62 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
63 
64 		/* Fill in some default values.
65 		 * Leave bmAttributes as zero, which will mean no streams for
66 		 * bulk, and isoc won't support multiple bursts of packets.
67 		 * With bursts of only one packet, and a Mult of 1, the max
68 		 * amount of data moved per endpoint service interval is one
69 		 * packet.
70 		 */
71 		ep->ss_ep_comp.bLength = USB_DT_SS_EP_COMP_SIZE;
72 		ep->ss_ep_comp.bDescriptorType = USB_DT_SS_ENDPOINT_COMP;
73 		if (usb_endpoint_xfer_isoc(&ep->desc) ||
74 				usb_endpoint_xfer_int(&ep->desc))
75 			ep->ss_ep_comp.wBytesPerInterval =
76 					ep->desc.wMaxPacketSize;
77 		return;
78 	}
79 
80 	memcpy(&ep->ss_ep_comp, desc, USB_DT_SS_EP_COMP_SIZE);
81 
82 	/* Check the various values */
83 	if (usb_endpoint_xfer_control(&ep->desc) && desc->bMaxBurst != 0) {
84 		dev_warn(ddev, "Control endpoint with bMaxBurst = %d in "
85 				"config %d interface %d altsetting %d ep %d: "
86 				"setting to zero\n", desc->bMaxBurst,
87 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
88 		ep->ss_ep_comp.bMaxBurst = 0;
89 	} else if (desc->bMaxBurst > 15) {
90 		dev_warn(ddev, "Endpoint with bMaxBurst = %d in "
91 				"config %d interface %d altsetting %d ep %d: "
92 				"setting to 15\n", desc->bMaxBurst,
93 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
94 		ep->ss_ep_comp.bMaxBurst = 15;
95 	}
96 
97 	if ((usb_endpoint_xfer_control(&ep->desc) ||
98 			usb_endpoint_xfer_int(&ep->desc)) &&
99 				desc->bmAttributes != 0) {
100 		dev_warn(ddev, "%s endpoint with bmAttributes = %d in "
101 				"config %d interface %d altsetting %d ep %d: "
102 				"setting to zero\n",
103 				usb_endpoint_xfer_control(&ep->desc) ? "Control" : "Bulk",
104 				desc->bmAttributes,
105 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
106 		ep->ss_ep_comp.bmAttributes = 0;
107 	} else if (usb_endpoint_xfer_bulk(&ep->desc) &&
108 			desc->bmAttributes > 16) {
109 		dev_warn(ddev, "Bulk endpoint with more than 65536 streams in "
110 				"config %d interface %d altsetting %d ep %d: "
111 				"setting to max\n",
112 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
113 		ep->ss_ep_comp.bmAttributes = 16;
114 	} else if (usb_endpoint_xfer_isoc(&ep->desc) &&
115 		   USB_SS_MULT(desc->bmAttributes) > 3) {
116 		dev_warn(ddev, "Isoc endpoint has Mult of %d in "
117 				"config %d interface %d altsetting %d ep %d: "
118 				"setting to 3\n",
119 				USB_SS_MULT(desc->bmAttributes),
120 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
121 		ep->ss_ep_comp.bmAttributes = 2;
122 	}
123 
124 	if (usb_endpoint_xfer_isoc(&ep->desc))
125 		max_tx = (desc->bMaxBurst + 1) *
126 			(USB_SS_MULT(desc->bmAttributes)) *
127 			usb_endpoint_maxp(&ep->desc);
128 	else if (usb_endpoint_xfer_int(&ep->desc))
129 		max_tx = usb_endpoint_maxp(&ep->desc) *
130 			(desc->bMaxBurst + 1);
131 	else
132 		max_tx = 999999;
133 	if (le16_to_cpu(desc->wBytesPerInterval) > max_tx) {
134 		dev_warn(ddev, "%s endpoint with wBytesPerInterval of %d in "
135 				"config %d interface %d altsetting %d ep %d: "
136 				"setting to %d\n",
137 				usb_endpoint_xfer_isoc(&ep->desc) ? "Isoc" : "Int",
138 				le16_to_cpu(desc->wBytesPerInterval),
139 				cfgno, inum, asnum, ep->desc.bEndpointAddress,
140 				max_tx);
141 		ep->ss_ep_comp.wBytesPerInterval = cpu_to_le16(max_tx);
142 	}
143 }
144 
145 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
146     int asnum, struct usb_host_interface *ifp, int num_ep,
147     unsigned char *buffer, int size)
148 {
149 	unsigned char *buffer0 = buffer;
150 	struct usb_endpoint_descriptor *d;
151 	struct usb_host_endpoint *endpoint;
152 	int n, i, j, retval;
153 
154 	d = (struct usb_endpoint_descriptor *) buffer;
155 	buffer += d->bLength;
156 	size -= d->bLength;
157 
158 	if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
159 		n = USB_DT_ENDPOINT_AUDIO_SIZE;
160 	else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
161 		n = USB_DT_ENDPOINT_SIZE;
162 	else {
163 		dev_warn(ddev, "config %d interface %d altsetting %d has an "
164 		    "invalid endpoint descriptor of length %d, skipping\n",
165 		    cfgno, inum, asnum, d->bLength);
166 		goto skip_to_next_endpoint_or_interface_descriptor;
167 	}
168 
169 	i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
170 	if (i >= 16 || i == 0) {
171 		dev_warn(ddev, "config %d interface %d altsetting %d has an "
172 		    "invalid endpoint with address 0x%X, skipping\n",
173 		    cfgno, inum, asnum, d->bEndpointAddress);
174 		goto skip_to_next_endpoint_or_interface_descriptor;
175 	}
176 
177 	/* Only store as many endpoints as we have room for */
178 	if (ifp->desc.bNumEndpoints >= num_ep)
179 		goto skip_to_next_endpoint_or_interface_descriptor;
180 
181 	endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
182 	++ifp->desc.bNumEndpoints;
183 
184 	memcpy(&endpoint->desc, d, n);
185 	INIT_LIST_HEAD(&endpoint->urb_list);
186 
187 	/* Fix up bInterval values outside the legal range. Use 32 ms if no
188 	 * proper value can be guessed. */
189 	i = 0;		/* i = min, j = max, n = default */
190 	j = 255;
191 	if (usb_endpoint_xfer_int(d)) {
192 		i = 1;
193 		switch (to_usb_device(ddev)->speed) {
194 		case USB_SPEED_SUPER:
195 		case USB_SPEED_HIGH:
196 			/* Many device manufacturers are using full-speed
197 			 * bInterval values in high-speed interrupt endpoint
198 			 * descriptors. Try to fix those and fall back to a
199 			 * 32 ms default value otherwise. */
200 			n = fls(d->bInterval*8);
201 			if (n == 0)
202 				n = 9;	/* 32 ms = 2^(9-1) uframes */
203 			j = 16;
204 
205 			/*
206 			 * Adjust bInterval for quirked devices.
207 			 * This quirk fixes bIntervals reported in
208 			 * linear microframes.
209 			 */
210 			if (to_usb_device(ddev)->quirks &
211 				USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL) {
212 				n = clamp(fls(d->bInterval), i, j);
213 				i = j = n;
214 			}
215 			break;
216 		default:		/* USB_SPEED_FULL or _LOW */
217 			/* For low-speed, 10 ms is the official minimum.
218 			 * But some "overclocked" devices might want faster
219 			 * polling so we'll allow it. */
220 			n = 32;
221 			break;
222 		}
223 	} else if (usb_endpoint_xfer_isoc(d)) {
224 		i = 1;
225 		j = 16;
226 		switch (to_usb_device(ddev)->speed) {
227 		case USB_SPEED_HIGH:
228 			n = 9;		/* 32 ms = 2^(9-1) uframes */
229 			break;
230 		default:		/* USB_SPEED_FULL */
231 			n = 6;		/* 32 ms = 2^(6-1) frames */
232 			break;
233 		}
234 	}
235 	if (d->bInterval < i || d->bInterval > j) {
236 		dev_warn(ddev, "config %d interface %d altsetting %d "
237 		    "endpoint 0x%X has an invalid bInterval %d, "
238 		    "changing to %d\n",
239 		    cfgno, inum, asnum,
240 		    d->bEndpointAddress, d->bInterval, n);
241 		endpoint->desc.bInterval = n;
242 	}
243 
244 	/* Some buggy low-speed devices have Bulk endpoints, which is
245 	 * explicitly forbidden by the USB spec.  In an attempt to make
246 	 * them usable, we will try treating them as Interrupt endpoints.
247 	 */
248 	if (to_usb_device(ddev)->speed == USB_SPEED_LOW &&
249 			usb_endpoint_xfer_bulk(d)) {
250 		dev_warn(ddev, "config %d interface %d altsetting %d "
251 		    "endpoint 0x%X is Bulk; changing to Interrupt\n",
252 		    cfgno, inum, asnum, d->bEndpointAddress);
253 		endpoint->desc.bmAttributes = USB_ENDPOINT_XFER_INT;
254 		endpoint->desc.bInterval = 1;
255 		if (usb_endpoint_maxp(&endpoint->desc) > 8)
256 			endpoint->desc.wMaxPacketSize = cpu_to_le16(8);
257 	}
258 
259 	/*
260 	 * Some buggy high speed devices have bulk endpoints using
261 	 * maxpacket sizes other than 512.  High speed HCDs may not
262 	 * be able to handle that particular bug, so let's warn...
263 	 */
264 	if (to_usb_device(ddev)->speed == USB_SPEED_HIGH
265 			&& usb_endpoint_xfer_bulk(d)) {
266 		unsigned maxp;
267 
268 		maxp = usb_endpoint_maxp(&endpoint->desc) & 0x07ff;
269 		if (maxp != 512)
270 			dev_warn(ddev, "config %d interface %d altsetting %d "
271 				"bulk endpoint 0x%X has invalid maxpacket %d\n",
272 				cfgno, inum, asnum, d->bEndpointAddress,
273 				maxp);
274 	}
275 
276 	/* Parse a possible SuperSpeed endpoint companion descriptor */
277 	if (to_usb_device(ddev)->speed == USB_SPEED_SUPER)
278 		usb_parse_ss_endpoint_companion(ddev, cfgno,
279 				inum, asnum, endpoint, buffer, size);
280 
281 	/* Skip over any Class Specific or Vendor Specific descriptors;
282 	 * find the next endpoint or interface descriptor */
283 	endpoint->extra = buffer;
284 	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
285 			USB_DT_INTERFACE, &n);
286 	endpoint->extralen = i;
287 	retval = buffer - buffer0 + i;
288 	if (n > 0)
289 		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
290 		    n, plural(n), "endpoint");
291 	return retval;
292 
293 skip_to_next_endpoint_or_interface_descriptor:
294 	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
295 	    USB_DT_INTERFACE, NULL);
296 	return buffer - buffer0 + i;
297 }
298 
299 void usb_release_interface_cache(struct kref *ref)
300 {
301 	struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
302 	int j;
303 
304 	for (j = 0; j < intfc->num_altsetting; j++) {
305 		struct usb_host_interface *alt = &intfc->altsetting[j];
306 
307 		kfree(alt->endpoint);
308 		kfree(alt->string);
309 	}
310 	kfree(intfc);
311 }
312 
313 static int usb_parse_interface(struct device *ddev, int cfgno,
314     struct usb_host_config *config, unsigned char *buffer, int size,
315     u8 inums[], u8 nalts[])
316 {
317 	unsigned char *buffer0 = buffer;
318 	struct usb_interface_descriptor	*d;
319 	int inum, asnum;
320 	struct usb_interface_cache *intfc;
321 	struct usb_host_interface *alt;
322 	int i, n;
323 	int len, retval;
324 	int num_ep, num_ep_orig;
325 
326 	d = (struct usb_interface_descriptor *) buffer;
327 	buffer += d->bLength;
328 	size -= d->bLength;
329 
330 	if (d->bLength < USB_DT_INTERFACE_SIZE)
331 		goto skip_to_next_interface_descriptor;
332 
333 	/* Which interface entry is this? */
334 	intfc = NULL;
335 	inum = d->bInterfaceNumber;
336 	for (i = 0; i < config->desc.bNumInterfaces; ++i) {
337 		if (inums[i] == inum) {
338 			intfc = config->intf_cache[i];
339 			break;
340 		}
341 	}
342 	if (!intfc || intfc->num_altsetting >= nalts[i])
343 		goto skip_to_next_interface_descriptor;
344 
345 	/* Check for duplicate altsetting entries */
346 	asnum = d->bAlternateSetting;
347 	for ((i = 0, alt = &intfc->altsetting[0]);
348 	      i < intfc->num_altsetting;
349 	     (++i, ++alt)) {
350 		if (alt->desc.bAlternateSetting == asnum) {
351 			dev_warn(ddev, "Duplicate descriptor for config %d "
352 			    "interface %d altsetting %d, skipping\n",
353 			    cfgno, inum, asnum);
354 			goto skip_to_next_interface_descriptor;
355 		}
356 	}
357 
358 	++intfc->num_altsetting;
359 	memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
360 
361 	/* Skip over any Class Specific or Vendor Specific descriptors;
362 	 * find the first endpoint or interface descriptor */
363 	alt->extra = buffer;
364 	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
365 	    USB_DT_INTERFACE, &n);
366 	alt->extralen = i;
367 	if (n > 0)
368 		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
369 		    n, plural(n), "interface");
370 	buffer += i;
371 	size -= i;
372 
373 	/* Allocate space for the right(?) number of endpoints */
374 	num_ep = num_ep_orig = alt->desc.bNumEndpoints;
375 	alt->desc.bNumEndpoints = 0;		/* Use as a counter */
376 	if (num_ep > USB_MAXENDPOINTS) {
377 		dev_warn(ddev, "too many endpoints for config %d interface %d "
378 		    "altsetting %d: %d, using maximum allowed: %d\n",
379 		    cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
380 		num_ep = USB_MAXENDPOINTS;
381 	}
382 
383 	if (num_ep > 0) {
384 		/* Can't allocate 0 bytes */
385 		len = sizeof(struct usb_host_endpoint) * num_ep;
386 		alt->endpoint = kzalloc(len, GFP_KERNEL);
387 		if (!alt->endpoint)
388 			return -ENOMEM;
389 	}
390 
391 	/* Parse all the endpoint descriptors */
392 	n = 0;
393 	while (size > 0) {
394 		if (((struct usb_descriptor_header *) buffer)->bDescriptorType
395 		     == USB_DT_INTERFACE)
396 			break;
397 		retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
398 		    num_ep, buffer, size);
399 		if (retval < 0)
400 			return retval;
401 		++n;
402 
403 		buffer += retval;
404 		size -= retval;
405 	}
406 
407 	if (n != num_ep_orig)
408 		dev_warn(ddev, "config %d interface %d altsetting %d has %d "
409 		    "endpoint descriptor%s, different from the interface "
410 		    "descriptor's value: %d\n",
411 		    cfgno, inum, asnum, n, plural(n), num_ep_orig);
412 	return buffer - buffer0;
413 
414 skip_to_next_interface_descriptor:
415 	i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
416 	    USB_DT_INTERFACE, NULL);
417 	return buffer - buffer0 + i;
418 }
419 
420 static int usb_parse_configuration(struct usb_device *dev, int cfgidx,
421     struct usb_host_config *config, unsigned char *buffer, int size)
422 {
423 	struct device *ddev = &dev->dev;
424 	unsigned char *buffer0 = buffer;
425 	int cfgno;
426 	int nintf, nintf_orig;
427 	int i, j, n;
428 	struct usb_interface_cache *intfc;
429 	unsigned char *buffer2;
430 	int size2;
431 	struct usb_descriptor_header *header;
432 	int len, retval;
433 	u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
434 	unsigned iad_num = 0;
435 
436 	memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
437 	if (config->desc.bDescriptorType != USB_DT_CONFIG ||
438 	    config->desc.bLength < USB_DT_CONFIG_SIZE ||
439 	    config->desc.bLength > size) {
440 		dev_err(ddev, "invalid descriptor for config index %d: "
441 		    "type = 0x%X, length = %d\n", cfgidx,
442 		    config->desc.bDescriptorType, config->desc.bLength);
443 		return -EINVAL;
444 	}
445 	cfgno = config->desc.bConfigurationValue;
446 
447 	buffer += config->desc.bLength;
448 	size -= config->desc.bLength;
449 
450 	nintf = nintf_orig = config->desc.bNumInterfaces;
451 	if (nintf > USB_MAXINTERFACES) {
452 		dev_warn(ddev, "config %d has too many interfaces: %d, "
453 		    "using maximum allowed: %d\n",
454 		    cfgno, nintf, USB_MAXINTERFACES);
455 		nintf = USB_MAXINTERFACES;
456 	}
457 
458 	/* Go through the descriptors, checking their length and counting the
459 	 * number of altsettings for each interface */
460 	n = 0;
461 	for ((buffer2 = buffer, size2 = size);
462 	      size2 > 0;
463 	     (buffer2 += header->bLength, size2 -= header->bLength)) {
464 
465 		if (size2 < sizeof(struct usb_descriptor_header)) {
466 			dev_warn(ddev, "config %d descriptor has %d excess "
467 			    "byte%s, ignoring\n",
468 			    cfgno, size2, plural(size2));
469 			break;
470 		}
471 
472 		header = (struct usb_descriptor_header *) buffer2;
473 		if ((header->bLength > size2) || (header->bLength < 2)) {
474 			dev_warn(ddev, "config %d has an invalid descriptor "
475 			    "of length %d, skipping remainder of the config\n",
476 			    cfgno, header->bLength);
477 			break;
478 		}
479 
480 		if (header->bDescriptorType == USB_DT_INTERFACE) {
481 			struct usb_interface_descriptor *d;
482 			int inum;
483 
484 			d = (struct usb_interface_descriptor *) header;
485 			if (d->bLength < USB_DT_INTERFACE_SIZE) {
486 				dev_warn(ddev, "config %d has an invalid "
487 				    "interface descriptor of length %d, "
488 				    "skipping\n", cfgno, d->bLength);
489 				continue;
490 			}
491 
492 			inum = d->bInterfaceNumber;
493 
494 			if ((dev->quirks & USB_QUIRK_HONOR_BNUMINTERFACES) &&
495 			    n >= nintf_orig) {
496 				dev_warn(ddev, "config %d has more interface "
497 				    "descriptors, than it declares in "
498 				    "bNumInterfaces, ignoring interface "
499 				    "number: %d\n", cfgno, inum);
500 				continue;
501 			}
502 
503 			if (inum >= nintf_orig)
504 				dev_warn(ddev, "config %d has an invalid "
505 				    "interface number: %d but max is %d\n",
506 				    cfgno, inum, nintf_orig - 1);
507 
508 			/* Have we already encountered this interface?
509 			 * Count its altsettings */
510 			for (i = 0; i < n; ++i) {
511 				if (inums[i] == inum)
512 					break;
513 			}
514 			if (i < n) {
515 				if (nalts[i] < 255)
516 					++nalts[i];
517 			} else if (n < USB_MAXINTERFACES) {
518 				inums[n] = inum;
519 				nalts[n] = 1;
520 				++n;
521 			}
522 
523 		} else if (header->bDescriptorType ==
524 				USB_DT_INTERFACE_ASSOCIATION) {
525 			if (iad_num == USB_MAXIADS) {
526 				dev_warn(ddev, "found more Interface "
527 					       "Association Descriptors "
528 					       "than allocated for in "
529 					       "configuration %d\n", cfgno);
530 			} else {
531 				config->intf_assoc[iad_num] =
532 					(struct usb_interface_assoc_descriptor
533 					*)header;
534 				iad_num++;
535 			}
536 
537 		} else if (header->bDescriptorType == USB_DT_DEVICE ||
538 			    header->bDescriptorType == USB_DT_CONFIG)
539 			dev_warn(ddev, "config %d contains an unexpected "
540 			    "descriptor of type 0x%X, skipping\n",
541 			    cfgno, header->bDescriptorType);
542 
543 	}	/* for ((buffer2 = buffer, size2 = size); ...) */
544 	size = buffer2 - buffer;
545 	config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
546 
547 	if (n != nintf)
548 		dev_warn(ddev, "config %d has %d interface%s, different from "
549 		    "the descriptor's value: %d\n",
550 		    cfgno, n, plural(n), nintf_orig);
551 	else if (n == 0)
552 		dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
553 	config->desc.bNumInterfaces = nintf = n;
554 
555 	/* Check for missing interface numbers */
556 	for (i = 0; i < nintf; ++i) {
557 		for (j = 0; j < nintf; ++j) {
558 			if (inums[j] == i)
559 				break;
560 		}
561 		if (j >= nintf)
562 			dev_warn(ddev, "config %d has no interface number "
563 			    "%d\n", cfgno, i);
564 	}
565 
566 	/* Allocate the usb_interface_caches and altsetting arrays */
567 	for (i = 0; i < nintf; ++i) {
568 		j = nalts[i];
569 		if (j > USB_MAXALTSETTING) {
570 			dev_warn(ddev, "too many alternate settings for "
571 			    "config %d interface %d: %d, "
572 			    "using maximum allowed: %d\n",
573 			    cfgno, inums[i], j, USB_MAXALTSETTING);
574 			nalts[i] = j = USB_MAXALTSETTING;
575 		}
576 
577 		len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
578 		config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
579 		if (!intfc)
580 			return -ENOMEM;
581 		kref_init(&intfc->ref);
582 	}
583 
584 	/* FIXME: parse the BOS descriptor */
585 
586 	/* Skip over any Class Specific or Vendor Specific descriptors;
587 	 * find the first interface descriptor */
588 	config->extra = buffer;
589 	i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
590 	    USB_DT_INTERFACE, &n);
591 	config->extralen = i;
592 	if (n > 0)
593 		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
594 		    n, plural(n), "configuration");
595 	buffer += i;
596 	size -= i;
597 
598 	/* Parse all the interface/altsetting descriptors */
599 	while (size > 0) {
600 		retval = usb_parse_interface(ddev, cfgno, config,
601 		    buffer, size, inums, nalts);
602 		if (retval < 0)
603 			return retval;
604 
605 		buffer += retval;
606 		size -= retval;
607 	}
608 
609 	/* Check for missing altsettings */
610 	for (i = 0; i < nintf; ++i) {
611 		intfc = config->intf_cache[i];
612 		for (j = 0; j < intfc->num_altsetting; ++j) {
613 			for (n = 0; n < intfc->num_altsetting; ++n) {
614 				if (intfc->altsetting[n].desc.
615 				    bAlternateSetting == j)
616 					break;
617 			}
618 			if (n >= intfc->num_altsetting)
619 				dev_warn(ddev, "config %d interface %d has no "
620 				    "altsetting %d\n", cfgno, inums[i], j);
621 		}
622 	}
623 
624 	return 0;
625 }
626 
627 /* hub-only!! ... and only exported for reset/reinit path.
628  * otherwise used internally on disconnect/destroy path
629  */
630 void usb_destroy_configuration(struct usb_device *dev)
631 {
632 	int c, i;
633 
634 	if (!dev->config)
635 		return;
636 
637 	if (dev->rawdescriptors) {
638 		for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
639 			kfree(dev->rawdescriptors[i]);
640 
641 		kfree(dev->rawdescriptors);
642 		dev->rawdescriptors = NULL;
643 	}
644 
645 	for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
646 		struct usb_host_config *cf = &dev->config[c];
647 
648 		kfree(cf->string);
649 		for (i = 0; i < cf->desc.bNumInterfaces; i++) {
650 			if (cf->intf_cache[i])
651 				kref_put(&cf->intf_cache[i]->ref,
652 					  usb_release_interface_cache);
653 		}
654 	}
655 	kfree(dev->config);
656 	dev->config = NULL;
657 }
658 
659 
660 /*
661  * Get the USB config descriptors, cache and parse'em
662  *
663  * hub-only!! ... and only in reset path, or usb_new_device()
664  * (used by real hubs and virtual root hubs)
665  */
666 int usb_get_configuration(struct usb_device *dev)
667 {
668 	struct device *ddev = &dev->dev;
669 	int ncfg = dev->descriptor.bNumConfigurations;
670 	int result = 0;
671 	unsigned int cfgno, length;
672 	unsigned char *bigbuffer;
673 	struct usb_config_descriptor *desc;
674 
675 	cfgno = 0;
676 	result = -ENOMEM;
677 	if (ncfg > USB_MAXCONFIG) {
678 		dev_warn(ddev, "too many configurations: %d, "
679 		    "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
680 		dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
681 	}
682 
683 	if (ncfg < 1) {
684 		dev_err(ddev, "no configurations\n");
685 		return -EINVAL;
686 	}
687 
688 	length = ncfg * sizeof(struct usb_host_config);
689 	dev->config = kzalloc(length, GFP_KERNEL);
690 	if (!dev->config)
691 		goto err2;
692 
693 	length = ncfg * sizeof(char *);
694 	dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
695 	if (!dev->rawdescriptors)
696 		goto err2;
697 
698 	desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
699 	if (!desc)
700 		goto err2;
701 
702 	result = 0;
703 	for (; cfgno < ncfg; cfgno++) {
704 		/* We grab just the first descriptor so we know how long
705 		 * the whole configuration is */
706 		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
707 		    desc, USB_DT_CONFIG_SIZE);
708 		if (result < 0) {
709 			dev_err(ddev, "unable to read config index %d "
710 			    "descriptor/%s: %d\n", cfgno, "start", result);
711 			if (result != -EPIPE)
712 				goto err;
713 			dev_err(ddev, "chopping to %d config(s)\n", cfgno);
714 			dev->descriptor.bNumConfigurations = cfgno;
715 			break;
716 		} else if (result < 4) {
717 			dev_err(ddev, "config index %d descriptor too short "
718 			    "(expected %i, got %i)\n", cfgno,
719 			    USB_DT_CONFIG_SIZE, result);
720 			result = -EINVAL;
721 			goto err;
722 		}
723 		length = max((int) le16_to_cpu(desc->wTotalLength),
724 		    USB_DT_CONFIG_SIZE);
725 
726 		/* Now that we know the length, get the whole thing */
727 		bigbuffer = kmalloc(length, GFP_KERNEL);
728 		if (!bigbuffer) {
729 			result = -ENOMEM;
730 			goto err;
731 		}
732 
733 		if (dev->quirks & USB_QUIRK_DELAY_INIT)
734 			msleep(100);
735 
736 		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
737 		    bigbuffer, length);
738 		if (result < 0) {
739 			dev_err(ddev, "unable to read config index %d "
740 			    "descriptor/%s\n", cfgno, "all");
741 			kfree(bigbuffer);
742 			goto err;
743 		}
744 		if (result < length) {
745 			dev_warn(ddev, "config index %d descriptor too short "
746 			    "(expected %i, got %i)\n", cfgno, length, result);
747 			length = result;
748 		}
749 
750 		dev->rawdescriptors[cfgno] = bigbuffer;
751 
752 		result = usb_parse_configuration(dev, cfgno,
753 		    &dev->config[cfgno], bigbuffer, length);
754 		if (result < 0) {
755 			++cfgno;
756 			goto err;
757 		}
758 	}
759 	result = 0;
760 
761 err:
762 	kfree(desc);
763 	dev->descriptor.bNumConfigurations = cfgno;
764 err2:
765 	if (result == -ENOMEM)
766 		dev_err(ddev, "out of memory\n");
767 	return result;
768 }
769 
770 void usb_release_bos_descriptor(struct usb_device *dev)
771 {
772 	if (dev->bos) {
773 		kfree(dev->bos->desc);
774 		kfree(dev->bos);
775 		dev->bos = NULL;
776 	}
777 }
778 
779 /* Get BOS descriptor set */
780 int usb_get_bos_descriptor(struct usb_device *dev)
781 {
782 	struct device *ddev = &dev->dev;
783 	struct usb_bos_descriptor *bos;
784 	struct usb_dev_cap_header *cap;
785 	unsigned char *buffer;
786 	int length, total_len, num, i;
787 	int ret;
788 
789 	bos = kzalloc(sizeof(struct usb_bos_descriptor), GFP_KERNEL);
790 	if (!bos)
791 		return -ENOMEM;
792 
793 	/* Get BOS descriptor */
794 	ret = usb_get_descriptor(dev, USB_DT_BOS, 0, bos, USB_DT_BOS_SIZE);
795 	if (ret < USB_DT_BOS_SIZE) {
796 		dev_err(ddev, "unable to get BOS descriptor\n");
797 		if (ret >= 0)
798 			ret = -ENOMSG;
799 		kfree(bos);
800 		return ret;
801 	}
802 
803 	length = bos->bLength;
804 	total_len = le16_to_cpu(bos->wTotalLength);
805 	num = bos->bNumDeviceCaps;
806 	kfree(bos);
807 	if (total_len < length)
808 		return -EINVAL;
809 
810 	dev->bos = kzalloc(sizeof(struct usb_host_bos), GFP_KERNEL);
811 	if (!dev->bos)
812 		return -ENOMEM;
813 
814 	/* Now let's get the whole BOS descriptor set */
815 	buffer = kzalloc(total_len, GFP_KERNEL);
816 	if (!buffer) {
817 		ret = -ENOMEM;
818 		goto err;
819 	}
820 	dev->bos->desc = (struct usb_bos_descriptor *)buffer;
821 
822 	ret = usb_get_descriptor(dev, USB_DT_BOS, 0, buffer, total_len);
823 	if (ret < total_len) {
824 		dev_err(ddev, "unable to get BOS descriptor set\n");
825 		if (ret >= 0)
826 			ret = -ENOMSG;
827 		goto err;
828 	}
829 	total_len -= length;
830 
831 	for (i = 0; i < num; i++) {
832 		buffer += length;
833 		cap = (struct usb_dev_cap_header *)buffer;
834 		length = cap->bLength;
835 
836 		if (total_len < length)
837 			break;
838 		total_len -= length;
839 
840 		if (cap->bDescriptorType != USB_DT_DEVICE_CAPABILITY) {
841 			dev_warn(ddev, "descriptor type invalid, skip\n");
842 			continue;
843 		}
844 
845 		switch (cap->bDevCapabilityType) {
846 		case USB_CAP_TYPE_WIRELESS_USB:
847 			/* Wireless USB cap descriptor is handled by wusb */
848 			break;
849 		case USB_CAP_TYPE_EXT:
850 			dev->bos->ext_cap =
851 				(struct usb_ext_cap_descriptor *)buffer;
852 			break;
853 		case USB_SS_CAP_TYPE:
854 			dev->bos->ss_cap =
855 				(struct usb_ss_cap_descriptor *)buffer;
856 			break;
857 		case USB_SSP_CAP_TYPE:
858 			dev->bos->ssp_cap =
859 				(struct usb_ssp_cap_descriptor *)buffer;
860 			break;
861 		case CONTAINER_ID_TYPE:
862 			dev->bos->ss_id =
863 				(struct usb_ss_container_id_descriptor *)buffer;
864 			break;
865 		default:
866 			break;
867 		}
868 	}
869 
870 	return 0;
871 
872 err:
873 	usb_release_bos_descriptor(dev);
874 	return ret;
875 }
876