xref: /openbmc/linux/drivers/usb/core/config.c (revision ae3473231e77a3f1909d48cd144cebe5e1d049b3)
1 /*
2  * Released under the GPLv2 only.
3  * SPDX-License-Identifier: GPL-2.0
4  */
5 
6 #include <linux/usb.h>
7 #include <linux/usb/ch9.h>
8 #include <linux/usb/hcd.h>
9 #include <linux/usb/quirks.h>
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/device.h>
13 #include <asm/byteorder.h>
14 #include "usb.h"
15 
16 
17 #define USB_MAXALTSETTING		128	/* Hard limit */
18 
19 #define USB_MAXCONFIG			8	/* Arbitrary limit */
20 
21 
22 static inline const char *plural(int n)
23 {
24 	return (n == 1 ? "" : "s");
25 }
26 
27 static int find_next_descriptor(unsigned char *buffer, int size,
28     int dt1, int dt2, int *num_skipped)
29 {
30 	struct usb_descriptor_header *h;
31 	int n = 0;
32 	unsigned char *buffer0 = buffer;
33 
34 	/* Find the next descriptor of type dt1 or dt2 */
35 	while (size > 0) {
36 		h = (struct usb_descriptor_header *) buffer;
37 		if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
38 			break;
39 		buffer += h->bLength;
40 		size -= h->bLength;
41 		++n;
42 	}
43 
44 	/* Store the number of descriptors skipped and return the
45 	 * number of bytes skipped */
46 	if (num_skipped)
47 		*num_skipped = n;
48 	return buffer - buffer0;
49 }
50 
51 static void usb_parse_ssp_isoc_endpoint_companion(struct device *ddev,
52 		int cfgno, int inum, int asnum, struct usb_host_endpoint *ep,
53 		unsigned char *buffer, int size)
54 {
55 	struct usb_ssp_isoc_ep_comp_descriptor *desc;
56 
57 	/*
58 	 * The SuperSpeedPlus Isoc endpoint companion descriptor immediately
59 	 * follows the SuperSpeed Endpoint Companion descriptor
60 	 */
61 	desc = (struct usb_ssp_isoc_ep_comp_descriptor *) buffer;
62 	if (desc->bDescriptorType != USB_DT_SSP_ISOC_ENDPOINT_COMP ||
63 	    size < USB_DT_SSP_ISOC_EP_COMP_SIZE) {
64 		dev_warn(ddev, "Invalid SuperSpeedPlus isoc endpoint companion"
65 			 "for config %d interface %d altsetting %d ep %d.\n",
66 			 cfgno, inum, asnum, ep->desc.bEndpointAddress);
67 		return;
68 	}
69 	memcpy(&ep->ssp_isoc_ep_comp, desc, USB_DT_SSP_ISOC_EP_COMP_SIZE);
70 }
71 
72 static void usb_parse_ss_endpoint_companion(struct device *ddev, int cfgno,
73 		int inum, int asnum, struct usb_host_endpoint *ep,
74 		unsigned char *buffer, int size)
75 {
76 	struct usb_ss_ep_comp_descriptor *desc;
77 	int max_tx;
78 
79 	/* The SuperSpeed endpoint companion descriptor is supposed to
80 	 * be the first thing immediately following the endpoint descriptor.
81 	 */
82 	desc = (struct usb_ss_ep_comp_descriptor *) buffer;
83 
84 	if (desc->bDescriptorType != USB_DT_SS_ENDPOINT_COMP ||
85 			size < USB_DT_SS_EP_COMP_SIZE) {
86 		dev_warn(ddev, "No SuperSpeed endpoint companion for config %d "
87 				" interface %d altsetting %d ep %d: "
88 				"using minimum values\n",
89 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
90 
91 		/* Fill in some default values.
92 		 * Leave bmAttributes as zero, which will mean no streams for
93 		 * bulk, and isoc won't support multiple bursts of packets.
94 		 * With bursts of only one packet, and a Mult of 1, the max
95 		 * amount of data moved per endpoint service interval is one
96 		 * packet.
97 		 */
98 		ep->ss_ep_comp.bLength = USB_DT_SS_EP_COMP_SIZE;
99 		ep->ss_ep_comp.bDescriptorType = USB_DT_SS_ENDPOINT_COMP;
100 		if (usb_endpoint_xfer_isoc(&ep->desc) ||
101 				usb_endpoint_xfer_int(&ep->desc))
102 			ep->ss_ep_comp.wBytesPerInterval =
103 					ep->desc.wMaxPacketSize;
104 		return;
105 	}
106 	buffer += desc->bLength;
107 	size -= desc->bLength;
108 	memcpy(&ep->ss_ep_comp, desc, USB_DT_SS_EP_COMP_SIZE);
109 
110 	/* Check the various values */
111 	if (usb_endpoint_xfer_control(&ep->desc) && desc->bMaxBurst != 0) {
112 		dev_warn(ddev, "Control endpoint with bMaxBurst = %d in "
113 				"config %d interface %d altsetting %d ep %d: "
114 				"setting to zero\n", desc->bMaxBurst,
115 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
116 		ep->ss_ep_comp.bMaxBurst = 0;
117 	} else if (desc->bMaxBurst > 15) {
118 		dev_warn(ddev, "Endpoint with bMaxBurst = %d in "
119 				"config %d interface %d altsetting %d ep %d: "
120 				"setting to 15\n", desc->bMaxBurst,
121 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
122 		ep->ss_ep_comp.bMaxBurst = 15;
123 	}
124 
125 	if ((usb_endpoint_xfer_control(&ep->desc) ||
126 			usb_endpoint_xfer_int(&ep->desc)) &&
127 				desc->bmAttributes != 0) {
128 		dev_warn(ddev, "%s endpoint with bmAttributes = %d in "
129 				"config %d interface %d altsetting %d ep %d: "
130 				"setting to zero\n",
131 				usb_endpoint_xfer_control(&ep->desc) ? "Control" : "Bulk",
132 				desc->bmAttributes,
133 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
134 		ep->ss_ep_comp.bmAttributes = 0;
135 	} else if (usb_endpoint_xfer_bulk(&ep->desc) &&
136 			desc->bmAttributes > 16) {
137 		dev_warn(ddev, "Bulk endpoint with more than 65536 streams in "
138 				"config %d interface %d altsetting %d ep %d: "
139 				"setting to max\n",
140 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
141 		ep->ss_ep_comp.bmAttributes = 16;
142 	} else if (usb_endpoint_xfer_isoc(&ep->desc) &&
143 		   !USB_SS_SSP_ISOC_COMP(desc->bmAttributes) &&
144 		   USB_SS_MULT(desc->bmAttributes) > 3) {
145 		dev_warn(ddev, "Isoc endpoint has Mult of %d in "
146 				"config %d interface %d altsetting %d ep %d: "
147 				"setting to 3\n",
148 				USB_SS_MULT(desc->bmAttributes),
149 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
150 		ep->ss_ep_comp.bmAttributes = 2;
151 	}
152 
153 	if (usb_endpoint_xfer_isoc(&ep->desc))
154 		max_tx = (desc->bMaxBurst + 1) *
155 			(USB_SS_MULT(desc->bmAttributes)) *
156 			usb_endpoint_maxp(&ep->desc);
157 	else if (usb_endpoint_xfer_int(&ep->desc))
158 		max_tx = usb_endpoint_maxp(&ep->desc) *
159 			(desc->bMaxBurst + 1);
160 	else
161 		max_tx = 999999;
162 	if (le16_to_cpu(desc->wBytesPerInterval) > max_tx) {
163 		dev_warn(ddev, "%s endpoint with wBytesPerInterval of %d in "
164 				"config %d interface %d altsetting %d ep %d: "
165 				"setting to %d\n",
166 				usb_endpoint_xfer_isoc(&ep->desc) ? "Isoc" : "Int",
167 				le16_to_cpu(desc->wBytesPerInterval),
168 				cfgno, inum, asnum, ep->desc.bEndpointAddress,
169 				max_tx);
170 		ep->ss_ep_comp.wBytesPerInterval = cpu_to_le16(max_tx);
171 	}
172 	/* Parse a possible SuperSpeedPlus isoc ep companion descriptor */
173 	if (usb_endpoint_xfer_isoc(&ep->desc) &&
174 	    USB_SS_SSP_ISOC_COMP(desc->bmAttributes))
175 		usb_parse_ssp_isoc_endpoint_companion(ddev, cfgno, inum, asnum,
176 							ep, buffer, size);
177 }
178 
179 static const unsigned short low_speed_maxpacket_maxes[4] = {
180 	[USB_ENDPOINT_XFER_CONTROL] = 8,
181 	[USB_ENDPOINT_XFER_ISOC] = 0,
182 	[USB_ENDPOINT_XFER_BULK] = 0,
183 	[USB_ENDPOINT_XFER_INT] = 8,
184 };
185 static const unsigned short full_speed_maxpacket_maxes[4] = {
186 	[USB_ENDPOINT_XFER_CONTROL] = 64,
187 	[USB_ENDPOINT_XFER_ISOC] = 1023,
188 	[USB_ENDPOINT_XFER_BULK] = 64,
189 	[USB_ENDPOINT_XFER_INT] = 64,
190 };
191 static const unsigned short high_speed_maxpacket_maxes[4] = {
192 	[USB_ENDPOINT_XFER_CONTROL] = 64,
193 	[USB_ENDPOINT_XFER_ISOC] = 1024,
194 	[USB_ENDPOINT_XFER_BULK] = 512,
195 	[USB_ENDPOINT_XFER_INT] = 1024,
196 };
197 static const unsigned short super_speed_maxpacket_maxes[4] = {
198 	[USB_ENDPOINT_XFER_CONTROL] = 512,
199 	[USB_ENDPOINT_XFER_ISOC] = 1024,
200 	[USB_ENDPOINT_XFER_BULK] = 1024,
201 	[USB_ENDPOINT_XFER_INT] = 1024,
202 };
203 
204 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
205     int asnum, struct usb_host_interface *ifp, int num_ep,
206     unsigned char *buffer, int size)
207 {
208 	unsigned char *buffer0 = buffer;
209 	struct usb_endpoint_descriptor *d;
210 	struct usb_host_endpoint *endpoint;
211 	int n, i, j, retval;
212 	unsigned int maxp;
213 	const unsigned short *maxpacket_maxes;
214 
215 	d = (struct usb_endpoint_descriptor *) buffer;
216 	buffer += d->bLength;
217 	size -= d->bLength;
218 
219 	if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
220 		n = USB_DT_ENDPOINT_AUDIO_SIZE;
221 	else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
222 		n = USB_DT_ENDPOINT_SIZE;
223 	else {
224 		dev_warn(ddev, "config %d interface %d altsetting %d has an "
225 		    "invalid endpoint descriptor of length %d, skipping\n",
226 		    cfgno, inum, asnum, d->bLength);
227 		goto skip_to_next_endpoint_or_interface_descriptor;
228 	}
229 
230 	i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
231 	if (i >= 16 || i == 0) {
232 		dev_warn(ddev, "config %d interface %d altsetting %d has an "
233 		    "invalid endpoint with address 0x%X, skipping\n",
234 		    cfgno, inum, asnum, d->bEndpointAddress);
235 		goto skip_to_next_endpoint_or_interface_descriptor;
236 	}
237 
238 	/* Only store as many endpoints as we have room for */
239 	if (ifp->desc.bNumEndpoints >= num_ep)
240 		goto skip_to_next_endpoint_or_interface_descriptor;
241 
242 	endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
243 	++ifp->desc.bNumEndpoints;
244 
245 	memcpy(&endpoint->desc, d, n);
246 	INIT_LIST_HEAD(&endpoint->urb_list);
247 
248 	/*
249 	 * Fix up bInterval values outside the legal range.
250 	 * Use 10 or 8 ms if no proper value can be guessed.
251 	 */
252 	i = 0;		/* i = min, j = max, n = default */
253 	j = 255;
254 	if (usb_endpoint_xfer_int(d)) {
255 		i = 1;
256 		switch (to_usb_device(ddev)->speed) {
257 		case USB_SPEED_SUPER_PLUS:
258 		case USB_SPEED_SUPER:
259 		case USB_SPEED_HIGH:
260 			/*
261 			 * Many device manufacturers are using full-speed
262 			 * bInterval values in high-speed interrupt endpoint
263 			 * descriptors. Try to fix those and fall back to an
264 			 * 8-ms default value otherwise.
265 			 */
266 			n = fls(d->bInterval*8);
267 			if (n == 0)
268 				n = 7;	/* 8 ms = 2^(7-1) uframes */
269 			j = 16;
270 
271 			/*
272 			 * Adjust bInterval for quirked devices.
273 			 * This quirk fixes bIntervals reported in
274 			 * linear microframes.
275 			 */
276 			if (to_usb_device(ddev)->quirks &
277 				USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL) {
278 				n = clamp(fls(d->bInterval), i, j);
279 				i = j = n;
280 			}
281 			break;
282 		default:		/* USB_SPEED_FULL or _LOW */
283 			/*
284 			 * For low-speed, 10 ms is the official minimum.
285 			 * But some "overclocked" devices might want faster
286 			 * polling so we'll allow it.
287 			 */
288 			n = 10;
289 			break;
290 		}
291 	} else if (usb_endpoint_xfer_isoc(d)) {
292 		i = 1;
293 		j = 16;
294 		switch (to_usb_device(ddev)->speed) {
295 		case USB_SPEED_HIGH:
296 			n = 7;		/* 8 ms = 2^(7-1) uframes */
297 			break;
298 		default:		/* USB_SPEED_FULL */
299 			n = 4;		/* 8 ms = 2^(4-1) frames */
300 			break;
301 		}
302 	}
303 	if (d->bInterval < i || d->bInterval > j) {
304 		dev_warn(ddev, "config %d interface %d altsetting %d "
305 		    "endpoint 0x%X has an invalid bInterval %d, "
306 		    "changing to %d\n",
307 		    cfgno, inum, asnum,
308 		    d->bEndpointAddress, d->bInterval, n);
309 		endpoint->desc.bInterval = n;
310 	}
311 
312 	/* Some buggy low-speed devices have Bulk endpoints, which is
313 	 * explicitly forbidden by the USB spec.  In an attempt to make
314 	 * them usable, we will try treating them as Interrupt endpoints.
315 	 */
316 	if (to_usb_device(ddev)->speed == USB_SPEED_LOW &&
317 			usb_endpoint_xfer_bulk(d)) {
318 		dev_warn(ddev, "config %d interface %d altsetting %d "
319 		    "endpoint 0x%X is Bulk; changing to Interrupt\n",
320 		    cfgno, inum, asnum, d->bEndpointAddress);
321 		endpoint->desc.bmAttributes = USB_ENDPOINT_XFER_INT;
322 		endpoint->desc.bInterval = 1;
323 		if (usb_endpoint_maxp(&endpoint->desc) > 8)
324 			endpoint->desc.wMaxPacketSize = cpu_to_le16(8);
325 	}
326 
327 	/* Validate the wMaxPacketSize field */
328 	maxp = usb_endpoint_maxp(&endpoint->desc);
329 
330 	/* Find the highest legal maxpacket size for this endpoint */
331 	i = 0;		/* additional transactions per microframe */
332 	switch (to_usb_device(ddev)->speed) {
333 	case USB_SPEED_LOW:
334 		maxpacket_maxes = low_speed_maxpacket_maxes;
335 		break;
336 	case USB_SPEED_FULL:
337 		maxpacket_maxes = full_speed_maxpacket_maxes;
338 		break;
339 	case USB_SPEED_HIGH:
340 		/* Bits 12..11 are allowed only for HS periodic endpoints */
341 		if (usb_endpoint_xfer_int(d) || usb_endpoint_xfer_isoc(d)) {
342 			i = maxp & (BIT(12) | BIT(11));
343 			maxp &= ~i;
344 		}
345 		/* fallthrough */
346 	default:
347 		maxpacket_maxes = high_speed_maxpacket_maxes;
348 		break;
349 	case USB_SPEED_SUPER:
350 	case USB_SPEED_SUPER_PLUS:
351 		maxpacket_maxes = super_speed_maxpacket_maxes;
352 		break;
353 	}
354 	j = maxpacket_maxes[usb_endpoint_type(&endpoint->desc)];
355 
356 	if (maxp > j) {
357 		dev_warn(ddev, "config %d interface %d altsetting %d endpoint 0x%X has invalid maxpacket %d, setting to %d\n",
358 		    cfgno, inum, asnum, d->bEndpointAddress, maxp, j);
359 		maxp = j;
360 		endpoint->desc.wMaxPacketSize = cpu_to_le16(i | maxp);
361 	}
362 
363 	/*
364 	 * Some buggy high speed devices have bulk endpoints using
365 	 * maxpacket sizes other than 512.  High speed HCDs may not
366 	 * be able to handle that particular bug, so let's warn...
367 	 */
368 	if (to_usb_device(ddev)->speed == USB_SPEED_HIGH
369 			&& usb_endpoint_xfer_bulk(d)) {
370 		if (maxp != 512)
371 			dev_warn(ddev, "config %d interface %d altsetting %d "
372 				"bulk endpoint 0x%X has invalid maxpacket %d\n",
373 				cfgno, inum, asnum, d->bEndpointAddress,
374 				maxp);
375 	}
376 
377 	/* Parse a possible SuperSpeed endpoint companion descriptor */
378 	if (to_usb_device(ddev)->speed >= USB_SPEED_SUPER)
379 		usb_parse_ss_endpoint_companion(ddev, cfgno,
380 				inum, asnum, endpoint, buffer, size);
381 
382 	/* Skip over any Class Specific or Vendor Specific descriptors;
383 	 * find the next endpoint or interface descriptor */
384 	endpoint->extra = buffer;
385 	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
386 			USB_DT_INTERFACE, &n);
387 	endpoint->extralen = i;
388 	retval = buffer - buffer0 + i;
389 	if (n > 0)
390 		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
391 		    n, plural(n), "endpoint");
392 	return retval;
393 
394 skip_to_next_endpoint_or_interface_descriptor:
395 	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
396 	    USB_DT_INTERFACE, NULL);
397 	return buffer - buffer0 + i;
398 }
399 
400 void usb_release_interface_cache(struct kref *ref)
401 {
402 	struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
403 	int j;
404 
405 	for (j = 0; j < intfc->num_altsetting; j++) {
406 		struct usb_host_interface *alt = &intfc->altsetting[j];
407 
408 		kfree(alt->endpoint);
409 		kfree(alt->string);
410 	}
411 	kfree(intfc);
412 }
413 
414 static int usb_parse_interface(struct device *ddev, int cfgno,
415     struct usb_host_config *config, unsigned char *buffer, int size,
416     u8 inums[], u8 nalts[])
417 {
418 	unsigned char *buffer0 = buffer;
419 	struct usb_interface_descriptor	*d;
420 	int inum, asnum;
421 	struct usb_interface_cache *intfc;
422 	struct usb_host_interface *alt;
423 	int i, n;
424 	int len, retval;
425 	int num_ep, num_ep_orig;
426 
427 	d = (struct usb_interface_descriptor *) buffer;
428 	buffer += d->bLength;
429 	size -= d->bLength;
430 
431 	if (d->bLength < USB_DT_INTERFACE_SIZE)
432 		goto skip_to_next_interface_descriptor;
433 
434 	/* Which interface entry is this? */
435 	intfc = NULL;
436 	inum = d->bInterfaceNumber;
437 	for (i = 0; i < config->desc.bNumInterfaces; ++i) {
438 		if (inums[i] == inum) {
439 			intfc = config->intf_cache[i];
440 			break;
441 		}
442 	}
443 	if (!intfc || intfc->num_altsetting >= nalts[i])
444 		goto skip_to_next_interface_descriptor;
445 
446 	/* Check for duplicate altsetting entries */
447 	asnum = d->bAlternateSetting;
448 	for ((i = 0, alt = &intfc->altsetting[0]);
449 	      i < intfc->num_altsetting;
450 	     (++i, ++alt)) {
451 		if (alt->desc.bAlternateSetting == asnum) {
452 			dev_warn(ddev, "Duplicate descriptor for config %d "
453 			    "interface %d altsetting %d, skipping\n",
454 			    cfgno, inum, asnum);
455 			goto skip_to_next_interface_descriptor;
456 		}
457 	}
458 
459 	++intfc->num_altsetting;
460 	memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
461 
462 	/* Skip over any Class Specific or Vendor Specific descriptors;
463 	 * find the first endpoint or interface descriptor */
464 	alt->extra = buffer;
465 	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
466 	    USB_DT_INTERFACE, &n);
467 	alt->extralen = i;
468 	if (n > 0)
469 		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
470 		    n, plural(n), "interface");
471 	buffer += i;
472 	size -= i;
473 
474 	/* Allocate space for the right(?) number of endpoints */
475 	num_ep = num_ep_orig = alt->desc.bNumEndpoints;
476 	alt->desc.bNumEndpoints = 0;		/* Use as a counter */
477 	if (num_ep > USB_MAXENDPOINTS) {
478 		dev_warn(ddev, "too many endpoints for config %d interface %d "
479 		    "altsetting %d: %d, using maximum allowed: %d\n",
480 		    cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
481 		num_ep = USB_MAXENDPOINTS;
482 	}
483 
484 	if (num_ep > 0) {
485 		/* Can't allocate 0 bytes */
486 		len = sizeof(struct usb_host_endpoint) * num_ep;
487 		alt->endpoint = kzalloc(len, GFP_KERNEL);
488 		if (!alt->endpoint)
489 			return -ENOMEM;
490 	}
491 
492 	/* Parse all the endpoint descriptors */
493 	n = 0;
494 	while (size > 0) {
495 		if (((struct usb_descriptor_header *) buffer)->bDescriptorType
496 		     == USB_DT_INTERFACE)
497 			break;
498 		retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
499 		    num_ep, buffer, size);
500 		if (retval < 0)
501 			return retval;
502 		++n;
503 
504 		buffer += retval;
505 		size -= retval;
506 	}
507 
508 	if (n != num_ep_orig)
509 		dev_warn(ddev, "config %d interface %d altsetting %d has %d "
510 		    "endpoint descriptor%s, different from the interface "
511 		    "descriptor's value: %d\n",
512 		    cfgno, inum, asnum, n, plural(n), num_ep_orig);
513 	return buffer - buffer0;
514 
515 skip_to_next_interface_descriptor:
516 	i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
517 	    USB_DT_INTERFACE, NULL);
518 	return buffer - buffer0 + i;
519 }
520 
521 static int usb_parse_configuration(struct usb_device *dev, int cfgidx,
522     struct usb_host_config *config, unsigned char *buffer, int size)
523 {
524 	struct device *ddev = &dev->dev;
525 	unsigned char *buffer0 = buffer;
526 	int cfgno;
527 	int nintf, nintf_orig;
528 	int i, j, n;
529 	struct usb_interface_cache *intfc;
530 	unsigned char *buffer2;
531 	int size2;
532 	struct usb_descriptor_header *header;
533 	int len, retval;
534 	u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
535 	unsigned iad_num = 0;
536 
537 	memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
538 	if (config->desc.bDescriptorType != USB_DT_CONFIG ||
539 	    config->desc.bLength < USB_DT_CONFIG_SIZE ||
540 	    config->desc.bLength > size) {
541 		dev_err(ddev, "invalid descriptor for config index %d: "
542 		    "type = 0x%X, length = %d\n", cfgidx,
543 		    config->desc.bDescriptorType, config->desc.bLength);
544 		return -EINVAL;
545 	}
546 	cfgno = config->desc.bConfigurationValue;
547 
548 	buffer += config->desc.bLength;
549 	size -= config->desc.bLength;
550 
551 	nintf = nintf_orig = config->desc.bNumInterfaces;
552 	if (nintf > USB_MAXINTERFACES) {
553 		dev_warn(ddev, "config %d has too many interfaces: %d, "
554 		    "using maximum allowed: %d\n",
555 		    cfgno, nintf, USB_MAXINTERFACES);
556 		nintf = USB_MAXINTERFACES;
557 	}
558 
559 	/* Go through the descriptors, checking their length and counting the
560 	 * number of altsettings for each interface */
561 	n = 0;
562 	for ((buffer2 = buffer, size2 = size);
563 	      size2 > 0;
564 	     (buffer2 += header->bLength, size2 -= header->bLength)) {
565 
566 		if (size2 < sizeof(struct usb_descriptor_header)) {
567 			dev_warn(ddev, "config %d descriptor has %d excess "
568 			    "byte%s, ignoring\n",
569 			    cfgno, size2, plural(size2));
570 			break;
571 		}
572 
573 		header = (struct usb_descriptor_header *) buffer2;
574 		if ((header->bLength > size2) || (header->bLength < 2)) {
575 			dev_warn(ddev, "config %d has an invalid descriptor "
576 			    "of length %d, skipping remainder of the config\n",
577 			    cfgno, header->bLength);
578 			break;
579 		}
580 
581 		if (header->bDescriptorType == USB_DT_INTERFACE) {
582 			struct usb_interface_descriptor *d;
583 			int inum;
584 
585 			d = (struct usb_interface_descriptor *) header;
586 			if (d->bLength < USB_DT_INTERFACE_SIZE) {
587 				dev_warn(ddev, "config %d has an invalid "
588 				    "interface descriptor of length %d, "
589 				    "skipping\n", cfgno, d->bLength);
590 				continue;
591 			}
592 
593 			inum = d->bInterfaceNumber;
594 
595 			if ((dev->quirks & USB_QUIRK_HONOR_BNUMINTERFACES) &&
596 			    n >= nintf_orig) {
597 				dev_warn(ddev, "config %d has more interface "
598 				    "descriptors, than it declares in "
599 				    "bNumInterfaces, ignoring interface "
600 				    "number: %d\n", cfgno, inum);
601 				continue;
602 			}
603 
604 			if (inum >= nintf_orig)
605 				dev_warn(ddev, "config %d has an invalid "
606 				    "interface number: %d but max is %d\n",
607 				    cfgno, inum, nintf_orig - 1);
608 
609 			/* Have we already encountered this interface?
610 			 * Count its altsettings */
611 			for (i = 0; i < n; ++i) {
612 				if (inums[i] == inum)
613 					break;
614 			}
615 			if (i < n) {
616 				if (nalts[i] < 255)
617 					++nalts[i];
618 			} else if (n < USB_MAXINTERFACES) {
619 				inums[n] = inum;
620 				nalts[n] = 1;
621 				++n;
622 			}
623 
624 		} else if (header->bDescriptorType ==
625 				USB_DT_INTERFACE_ASSOCIATION) {
626 			if (iad_num == USB_MAXIADS) {
627 				dev_warn(ddev, "found more Interface "
628 					       "Association Descriptors "
629 					       "than allocated for in "
630 					       "configuration %d\n", cfgno);
631 			} else {
632 				config->intf_assoc[iad_num] =
633 					(struct usb_interface_assoc_descriptor
634 					*)header;
635 				iad_num++;
636 			}
637 
638 		} else if (header->bDescriptorType == USB_DT_DEVICE ||
639 			    header->bDescriptorType == USB_DT_CONFIG)
640 			dev_warn(ddev, "config %d contains an unexpected "
641 			    "descriptor of type 0x%X, skipping\n",
642 			    cfgno, header->bDescriptorType);
643 
644 	}	/* for ((buffer2 = buffer, size2 = size); ...) */
645 	size = buffer2 - buffer;
646 	config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
647 
648 	if (n != nintf)
649 		dev_warn(ddev, "config %d has %d interface%s, different from "
650 		    "the descriptor's value: %d\n",
651 		    cfgno, n, plural(n), nintf_orig);
652 	else if (n == 0)
653 		dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
654 	config->desc.bNumInterfaces = nintf = n;
655 
656 	/* Check for missing interface numbers */
657 	for (i = 0; i < nintf; ++i) {
658 		for (j = 0; j < nintf; ++j) {
659 			if (inums[j] == i)
660 				break;
661 		}
662 		if (j >= nintf)
663 			dev_warn(ddev, "config %d has no interface number "
664 			    "%d\n", cfgno, i);
665 	}
666 
667 	/* Allocate the usb_interface_caches and altsetting arrays */
668 	for (i = 0; i < nintf; ++i) {
669 		j = nalts[i];
670 		if (j > USB_MAXALTSETTING) {
671 			dev_warn(ddev, "too many alternate settings for "
672 			    "config %d interface %d: %d, "
673 			    "using maximum allowed: %d\n",
674 			    cfgno, inums[i], j, USB_MAXALTSETTING);
675 			nalts[i] = j = USB_MAXALTSETTING;
676 		}
677 
678 		len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
679 		config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
680 		if (!intfc)
681 			return -ENOMEM;
682 		kref_init(&intfc->ref);
683 	}
684 
685 	/* FIXME: parse the BOS descriptor */
686 
687 	/* Skip over any Class Specific or Vendor Specific descriptors;
688 	 * find the first interface descriptor */
689 	config->extra = buffer;
690 	i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
691 	    USB_DT_INTERFACE, &n);
692 	config->extralen = i;
693 	if (n > 0)
694 		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
695 		    n, plural(n), "configuration");
696 	buffer += i;
697 	size -= i;
698 
699 	/* Parse all the interface/altsetting descriptors */
700 	while (size > 0) {
701 		retval = usb_parse_interface(ddev, cfgno, config,
702 		    buffer, size, inums, nalts);
703 		if (retval < 0)
704 			return retval;
705 
706 		buffer += retval;
707 		size -= retval;
708 	}
709 
710 	/* Check for missing altsettings */
711 	for (i = 0; i < nintf; ++i) {
712 		intfc = config->intf_cache[i];
713 		for (j = 0; j < intfc->num_altsetting; ++j) {
714 			for (n = 0; n < intfc->num_altsetting; ++n) {
715 				if (intfc->altsetting[n].desc.
716 				    bAlternateSetting == j)
717 					break;
718 			}
719 			if (n >= intfc->num_altsetting)
720 				dev_warn(ddev, "config %d interface %d has no "
721 				    "altsetting %d\n", cfgno, inums[i], j);
722 		}
723 	}
724 
725 	return 0;
726 }
727 
728 /* hub-only!! ... and only exported for reset/reinit path.
729  * otherwise used internally on disconnect/destroy path
730  */
731 void usb_destroy_configuration(struct usb_device *dev)
732 {
733 	int c, i;
734 
735 	if (!dev->config)
736 		return;
737 
738 	if (dev->rawdescriptors) {
739 		for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
740 			kfree(dev->rawdescriptors[i]);
741 
742 		kfree(dev->rawdescriptors);
743 		dev->rawdescriptors = NULL;
744 	}
745 
746 	for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
747 		struct usb_host_config *cf = &dev->config[c];
748 
749 		kfree(cf->string);
750 		for (i = 0; i < cf->desc.bNumInterfaces; i++) {
751 			if (cf->intf_cache[i])
752 				kref_put(&cf->intf_cache[i]->ref,
753 					  usb_release_interface_cache);
754 		}
755 	}
756 	kfree(dev->config);
757 	dev->config = NULL;
758 }
759 
760 
761 /*
762  * Get the USB config descriptors, cache and parse'em
763  *
764  * hub-only!! ... and only in reset path, or usb_new_device()
765  * (used by real hubs and virtual root hubs)
766  */
767 int usb_get_configuration(struct usb_device *dev)
768 {
769 	struct device *ddev = &dev->dev;
770 	int ncfg = dev->descriptor.bNumConfigurations;
771 	int result = 0;
772 	unsigned int cfgno, length;
773 	unsigned char *bigbuffer;
774 	struct usb_config_descriptor *desc;
775 
776 	cfgno = 0;
777 	result = -ENOMEM;
778 	if (ncfg > USB_MAXCONFIG) {
779 		dev_warn(ddev, "too many configurations: %d, "
780 		    "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
781 		dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
782 	}
783 
784 	if (ncfg < 1) {
785 		dev_err(ddev, "no configurations\n");
786 		return -EINVAL;
787 	}
788 
789 	length = ncfg * sizeof(struct usb_host_config);
790 	dev->config = kzalloc(length, GFP_KERNEL);
791 	if (!dev->config)
792 		goto err2;
793 
794 	length = ncfg * sizeof(char *);
795 	dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
796 	if (!dev->rawdescriptors)
797 		goto err2;
798 
799 	desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
800 	if (!desc)
801 		goto err2;
802 
803 	result = 0;
804 	for (; cfgno < ncfg; cfgno++) {
805 		/* We grab just the first descriptor so we know how long
806 		 * the whole configuration is */
807 		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
808 		    desc, USB_DT_CONFIG_SIZE);
809 		if (result < 0) {
810 			dev_err(ddev, "unable to read config index %d "
811 			    "descriptor/%s: %d\n", cfgno, "start", result);
812 			if (result != -EPIPE)
813 				goto err;
814 			dev_err(ddev, "chopping to %d config(s)\n", cfgno);
815 			dev->descriptor.bNumConfigurations = cfgno;
816 			break;
817 		} else if (result < 4) {
818 			dev_err(ddev, "config index %d descriptor too short "
819 			    "(expected %i, got %i)\n", cfgno,
820 			    USB_DT_CONFIG_SIZE, result);
821 			result = -EINVAL;
822 			goto err;
823 		}
824 		length = max((int) le16_to_cpu(desc->wTotalLength),
825 		    USB_DT_CONFIG_SIZE);
826 
827 		/* Now that we know the length, get the whole thing */
828 		bigbuffer = kmalloc(length, GFP_KERNEL);
829 		if (!bigbuffer) {
830 			result = -ENOMEM;
831 			goto err;
832 		}
833 
834 		if (dev->quirks & USB_QUIRK_DELAY_INIT)
835 			msleep(100);
836 
837 		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
838 		    bigbuffer, length);
839 		if (result < 0) {
840 			dev_err(ddev, "unable to read config index %d "
841 			    "descriptor/%s\n", cfgno, "all");
842 			kfree(bigbuffer);
843 			goto err;
844 		}
845 		if (result < length) {
846 			dev_warn(ddev, "config index %d descriptor too short "
847 			    "(expected %i, got %i)\n", cfgno, length, result);
848 			length = result;
849 		}
850 
851 		dev->rawdescriptors[cfgno] = bigbuffer;
852 
853 		result = usb_parse_configuration(dev, cfgno,
854 		    &dev->config[cfgno], bigbuffer, length);
855 		if (result < 0) {
856 			++cfgno;
857 			goto err;
858 		}
859 	}
860 	result = 0;
861 
862 err:
863 	kfree(desc);
864 	dev->descriptor.bNumConfigurations = cfgno;
865 err2:
866 	if (result == -ENOMEM)
867 		dev_err(ddev, "out of memory\n");
868 	return result;
869 }
870 
871 void usb_release_bos_descriptor(struct usb_device *dev)
872 {
873 	if (dev->bos) {
874 		kfree(dev->bos->desc);
875 		kfree(dev->bos);
876 		dev->bos = NULL;
877 	}
878 }
879 
880 /* Get BOS descriptor set */
881 int usb_get_bos_descriptor(struct usb_device *dev)
882 {
883 	struct device *ddev = &dev->dev;
884 	struct usb_bos_descriptor *bos;
885 	struct usb_dev_cap_header *cap;
886 	unsigned char *buffer;
887 	int length, total_len, num, i;
888 	int ret;
889 
890 	bos = kzalloc(sizeof(struct usb_bos_descriptor), GFP_KERNEL);
891 	if (!bos)
892 		return -ENOMEM;
893 
894 	/* Get BOS descriptor */
895 	ret = usb_get_descriptor(dev, USB_DT_BOS, 0, bos, USB_DT_BOS_SIZE);
896 	if (ret < USB_DT_BOS_SIZE) {
897 		dev_err(ddev, "unable to get BOS descriptor\n");
898 		if (ret >= 0)
899 			ret = -ENOMSG;
900 		kfree(bos);
901 		return ret;
902 	}
903 
904 	length = bos->bLength;
905 	total_len = le16_to_cpu(bos->wTotalLength);
906 	num = bos->bNumDeviceCaps;
907 	kfree(bos);
908 	if (total_len < length)
909 		return -EINVAL;
910 
911 	dev->bos = kzalloc(sizeof(struct usb_host_bos), GFP_KERNEL);
912 	if (!dev->bos)
913 		return -ENOMEM;
914 
915 	/* Now let's get the whole BOS descriptor set */
916 	buffer = kzalloc(total_len, GFP_KERNEL);
917 	if (!buffer) {
918 		ret = -ENOMEM;
919 		goto err;
920 	}
921 	dev->bos->desc = (struct usb_bos_descriptor *)buffer;
922 
923 	ret = usb_get_descriptor(dev, USB_DT_BOS, 0, buffer, total_len);
924 	if (ret < total_len) {
925 		dev_err(ddev, "unable to get BOS descriptor set\n");
926 		if (ret >= 0)
927 			ret = -ENOMSG;
928 		goto err;
929 	}
930 	total_len -= length;
931 
932 	for (i = 0; i < num; i++) {
933 		buffer += length;
934 		cap = (struct usb_dev_cap_header *)buffer;
935 		length = cap->bLength;
936 
937 		if (total_len < length)
938 			break;
939 		total_len -= length;
940 
941 		if (cap->bDescriptorType != USB_DT_DEVICE_CAPABILITY) {
942 			dev_warn(ddev, "descriptor type invalid, skip\n");
943 			continue;
944 		}
945 
946 		switch (cap->bDevCapabilityType) {
947 		case USB_CAP_TYPE_WIRELESS_USB:
948 			/* Wireless USB cap descriptor is handled by wusb */
949 			break;
950 		case USB_CAP_TYPE_EXT:
951 			dev->bos->ext_cap =
952 				(struct usb_ext_cap_descriptor *)buffer;
953 			break;
954 		case USB_SS_CAP_TYPE:
955 			dev->bos->ss_cap =
956 				(struct usb_ss_cap_descriptor *)buffer;
957 			break;
958 		case USB_SSP_CAP_TYPE:
959 			dev->bos->ssp_cap =
960 				(struct usb_ssp_cap_descriptor *)buffer;
961 			break;
962 		case CONTAINER_ID_TYPE:
963 			dev->bos->ss_id =
964 				(struct usb_ss_container_id_descriptor *)buffer;
965 			break;
966 		case USB_PTM_CAP_TYPE:
967 			dev->bos->ptm_cap =
968 				(struct usb_ptm_cap_descriptor *)buffer;
969 		default:
970 			break;
971 		}
972 	}
973 
974 	return 0;
975 
976 err:
977 	usb_release_bos_descriptor(dev);
978 	return ret;
979 }
980