xref: /openbmc/linux/drivers/usb/gadget/configfs.c (revision 6c870213d6f3a25981c10728f46294a3bed1703f)
1 #include <linux/configfs.h>
2 #include <linux/module.h>
3 #include <linux/slab.h>
4 #include <linux/device.h>
5 #include <linux/usb/composite.h>
6 #include <linux/usb/gadget_configfs.h>
7 #include "configfs.h"
8 
9 int check_user_usb_string(const char *name,
10 		struct usb_gadget_strings *stringtab_dev)
11 {
12 	unsigned primary_lang;
13 	unsigned sub_lang;
14 	u16 num;
15 	int ret;
16 
17 	ret = kstrtou16(name, 0, &num);
18 	if (ret)
19 		return ret;
20 
21 	primary_lang = num & 0x3ff;
22 	sub_lang = num >> 10;
23 
24 	/* simple sanity check for valid langid */
25 	switch (primary_lang) {
26 	case 0:
27 	case 0x62 ... 0xfe:
28 	case 0x100 ... 0x3ff:
29 		return -EINVAL;
30 	}
31 	if (!sub_lang)
32 		return -EINVAL;
33 
34 	stringtab_dev->language = num;
35 	return 0;
36 }
37 
38 #define MAX_NAME_LEN	40
39 #define MAX_USB_STRING_LANGS 2
40 
41 struct gadget_info {
42 	struct config_group group;
43 	struct config_group functions_group;
44 	struct config_group configs_group;
45 	struct config_group strings_group;
46 	struct config_group *default_groups[4];
47 
48 	struct mutex lock;
49 	struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
50 	struct list_head string_list;
51 	struct list_head available_func;
52 
53 	const char *udc_name;
54 #ifdef CONFIG_USB_OTG
55 	struct usb_otg_descriptor otg;
56 #endif
57 	struct usb_composite_driver composite;
58 	struct usb_composite_dev cdev;
59 };
60 
61 struct config_usb_cfg {
62 	struct config_group group;
63 	struct config_group strings_group;
64 	struct config_group *default_groups[2];
65 	struct list_head string_list;
66 	struct usb_configuration c;
67 	struct list_head func_list;
68 	struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
69 };
70 
71 struct gadget_strings {
72 	struct usb_gadget_strings stringtab_dev;
73 	struct usb_string strings[USB_GADGET_FIRST_AVAIL_IDX];
74 	char *manufacturer;
75 	char *product;
76 	char *serialnumber;
77 
78 	struct config_group group;
79 	struct list_head list;
80 };
81 
82 struct gadget_config_name {
83 	struct usb_gadget_strings stringtab_dev;
84 	struct usb_string strings;
85 	char *configuration;
86 
87 	struct config_group group;
88 	struct list_head list;
89 };
90 
91 static int usb_string_copy(const char *s, char **s_copy)
92 {
93 	int ret;
94 	char *str;
95 	char *copy = *s_copy;
96 	ret = strlen(s);
97 	if (ret > 126)
98 		return -EOVERFLOW;
99 
100 	str = kstrdup(s, GFP_KERNEL);
101 	if (!str)
102 		return -ENOMEM;
103 	if (str[ret - 1] == '\n')
104 		str[ret - 1] = '\0';
105 	kfree(copy);
106 	*s_copy = str;
107 	return 0;
108 }
109 
110 CONFIGFS_ATTR_STRUCT(gadget_info);
111 CONFIGFS_ATTR_STRUCT(config_usb_cfg);
112 
113 #define GI_DEVICE_DESC_ITEM_ATTR(name)	\
114 	static struct gadget_info_attribute gadget_cdev_desc_##name = \
115 		__CONFIGFS_ATTR(name,  S_IRUGO | S_IWUSR,		\
116 				gadget_dev_desc_##name##_show,		\
117 				gadget_dev_desc_##name##_store)
118 
119 #define GI_DEVICE_DESC_SIMPLE_R_u8(__name)	\
120 	static ssize_t gadget_dev_desc_##__name##_show(struct gadget_info *gi, \
121 			char *page)	\
122 {	\
123 	return sprintf(page, "0x%02x\n", gi->cdev.desc.__name);	\
124 }
125 
126 #define GI_DEVICE_DESC_SIMPLE_R_u16(__name)	\
127 	static ssize_t gadget_dev_desc_##__name##_show(struct gadget_info *gi, \
128 			char *page)	\
129 {	\
130 	return sprintf(page, "0x%04x\n", le16_to_cpup(&gi->cdev.desc.__name)); \
131 }
132 
133 
134 #define GI_DEVICE_DESC_SIMPLE_W_u8(_name)		\
135 	static ssize_t gadget_dev_desc_##_name##_store(struct gadget_info *gi, \
136 		const char *page, size_t len)		\
137 {							\
138 	u8 val;						\
139 	int ret;					\
140 	ret = kstrtou8(page, 0, &val);			\
141 	if (ret)					\
142 		return ret;				\
143 	gi->cdev.desc._name = val;			\
144 	return len;					\
145 }
146 
147 #define GI_DEVICE_DESC_SIMPLE_W_u16(_name)	\
148 	static ssize_t gadget_dev_desc_##_name##_store(struct gadget_info *gi, \
149 		const char *page, size_t len)		\
150 {							\
151 	u16 val;					\
152 	int ret;					\
153 	ret = kstrtou16(page, 0, &val);			\
154 	if (ret)					\
155 		return ret;				\
156 	gi->cdev.desc._name = cpu_to_le16p(&val);	\
157 	return len;					\
158 }
159 
160 #define GI_DEVICE_DESC_SIMPLE_RW(_name, _type)	\
161 	GI_DEVICE_DESC_SIMPLE_R_##_type(_name)	\
162 	GI_DEVICE_DESC_SIMPLE_W_##_type(_name)
163 
164 GI_DEVICE_DESC_SIMPLE_R_u16(bcdUSB);
165 GI_DEVICE_DESC_SIMPLE_RW(bDeviceClass, u8);
166 GI_DEVICE_DESC_SIMPLE_RW(bDeviceSubClass, u8);
167 GI_DEVICE_DESC_SIMPLE_RW(bDeviceProtocol, u8);
168 GI_DEVICE_DESC_SIMPLE_RW(bMaxPacketSize0, u8);
169 GI_DEVICE_DESC_SIMPLE_RW(idVendor, u16);
170 GI_DEVICE_DESC_SIMPLE_RW(idProduct, u16);
171 GI_DEVICE_DESC_SIMPLE_R_u16(bcdDevice);
172 
173 static ssize_t is_valid_bcd(u16 bcd_val)
174 {
175 	if ((bcd_val & 0xf) > 9)
176 		return -EINVAL;
177 	if (((bcd_val >> 4) & 0xf) > 9)
178 		return -EINVAL;
179 	if (((bcd_val >> 8) & 0xf) > 9)
180 		return -EINVAL;
181 	if (((bcd_val >> 12) & 0xf) > 9)
182 		return -EINVAL;
183 	return 0;
184 }
185 
186 static ssize_t gadget_dev_desc_bcdDevice_store(struct gadget_info *gi,
187 		const char *page, size_t len)
188 {
189 	u16 bcdDevice;
190 	int ret;
191 
192 	ret = kstrtou16(page, 0, &bcdDevice);
193 	if (ret)
194 		return ret;
195 	ret = is_valid_bcd(bcdDevice);
196 	if (ret)
197 		return ret;
198 
199 	gi->cdev.desc.bcdDevice = cpu_to_le16(bcdDevice);
200 	return len;
201 }
202 
203 static ssize_t gadget_dev_desc_bcdUSB_store(struct gadget_info *gi,
204 		const char *page, size_t len)
205 {
206 	u16 bcdUSB;
207 	int ret;
208 
209 	ret = kstrtou16(page, 0, &bcdUSB);
210 	if (ret)
211 		return ret;
212 	ret = is_valid_bcd(bcdUSB);
213 	if (ret)
214 		return ret;
215 
216 	gi->cdev.desc.bcdUSB = cpu_to_le16(bcdUSB);
217 	return len;
218 }
219 
220 static ssize_t gadget_dev_desc_UDC_show(struct gadget_info *gi, char *page)
221 {
222 	return sprintf(page, "%s\n", gi->udc_name ?: "");
223 }
224 
225 static int unregister_gadget(struct gadget_info *gi)
226 {
227 	int ret;
228 
229 	if (!gi->udc_name)
230 		return -ENODEV;
231 
232 	ret = usb_gadget_unregister_driver(&gi->composite.gadget_driver);
233 	if (ret)
234 		return ret;
235 	kfree(gi->udc_name);
236 	gi->udc_name = NULL;
237 	return 0;
238 }
239 
240 static ssize_t gadget_dev_desc_UDC_store(struct gadget_info *gi,
241 		const char *page, size_t len)
242 {
243 	char *name;
244 	int ret;
245 
246 	name = kstrdup(page, GFP_KERNEL);
247 	if (!name)
248 		return -ENOMEM;
249 	if (name[len - 1] == '\n')
250 		name[len - 1] = '\0';
251 
252 	mutex_lock(&gi->lock);
253 
254 	if (!strlen(name)) {
255 		ret = unregister_gadget(gi);
256 		if (ret)
257 			goto err;
258 	} else {
259 		if (gi->udc_name) {
260 			ret = -EBUSY;
261 			goto err;
262 		}
263 		ret = udc_attach_driver(name, &gi->composite.gadget_driver);
264 		if (ret)
265 			goto err;
266 		gi->udc_name = name;
267 	}
268 	mutex_unlock(&gi->lock);
269 	return len;
270 err:
271 	kfree(name);
272 	mutex_unlock(&gi->lock);
273 	return ret;
274 }
275 
276 GI_DEVICE_DESC_ITEM_ATTR(bDeviceClass);
277 GI_DEVICE_DESC_ITEM_ATTR(bDeviceSubClass);
278 GI_DEVICE_DESC_ITEM_ATTR(bDeviceProtocol);
279 GI_DEVICE_DESC_ITEM_ATTR(bMaxPacketSize0);
280 GI_DEVICE_DESC_ITEM_ATTR(idVendor);
281 GI_DEVICE_DESC_ITEM_ATTR(idProduct);
282 GI_DEVICE_DESC_ITEM_ATTR(bcdDevice);
283 GI_DEVICE_DESC_ITEM_ATTR(bcdUSB);
284 GI_DEVICE_DESC_ITEM_ATTR(UDC);
285 
286 static struct configfs_attribute *gadget_root_attrs[] = {
287 	&gadget_cdev_desc_bDeviceClass.attr,
288 	&gadget_cdev_desc_bDeviceSubClass.attr,
289 	&gadget_cdev_desc_bDeviceProtocol.attr,
290 	&gadget_cdev_desc_bMaxPacketSize0.attr,
291 	&gadget_cdev_desc_idVendor.attr,
292 	&gadget_cdev_desc_idProduct.attr,
293 	&gadget_cdev_desc_bcdDevice.attr,
294 	&gadget_cdev_desc_bcdUSB.attr,
295 	&gadget_cdev_desc_UDC.attr,
296 	NULL,
297 };
298 
299 static inline struct gadget_info *to_gadget_info(struct config_item *item)
300 {
301 	 return container_of(to_config_group(item), struct gadget_info, group);
302 }
303 
304 static inline struct gadget_strings *to_gadget_strings(struct config_item *item)
305 {
306 	 return container_of(to_config_group(item), struct gadget_strings,
307 			 group);
308 }
309 
310 static inline struct gadget_config_name *to_gadget_config_name(
311 		struct config_item *item)
312 {
313 	 return container_of(to_config_group(item), struct gadget_config_name,
314 			 group);
315 }
316 
317 static inline struct config_usb_cfg *to_config_usb_cfg(struct config_item *item)
318 {
319 	return container_of(to_config_group(item), struct config_usb_cfg,
320 			group);
321 }
322 
323 static inline struct usb_function_instance *to_usb_function_instance(
324 		struct config_item *item)
325 {
326 	 return container_of(to_config_group(item),
327 			 struct usb_function_instance, group);
328 }
329 
330 static void gadget_info_attr_release(struct config_item *item)
331 {
332 	struct gadget_info *gi = to_gadget_info(item);
333 
334 	WARN_ON(!list_empty(&gi->cdev.configs));
335 	WARN_ON(!list_empty(&gi->string_list));
336 	WARN_ON(!list_empty(&gi->available_func));
337 	kfree(gi->composite.gadget_driver.function);
338 	kfree(gi);
339 }
340 
341 CONFIGFS_ATTR_OPS(gadget_info);
342 
343 static struct configfs_item_operations gadget_root_item_ops = {
344 	.release                = gadget_info_attr_release,
345 	.show_attribute         = gadget_info_attr_show,
346 	.store_attribute        = gadget_info_attr_store,
347 };
348 
349 static void gadget_config_attr_release(struct config_item *item)
350 {
351 	struct config_usb_cfg *cfg = to_config_usb_cfg(item);
352 
353 	WARN_ON(!list_empty(&cfg->c.functions));
354 	list_del(&cfg->c.list);
355 	kfree(cfg->c.label);
356 	kfree(cfg);
357 }
358 
359 static int config_usb_cfg_link(
360 	struct config_item *usb_cfg_ci,
361 	struct config_item *usb_func_ci)
362 {
363 	struct config_usb_cfg *cfg = to_config_usb_cfg(usb_cfg_ci);
364 	struct usb_composite_dev *cdev = cfg->c.cdev;
365 	struct gadget_info *gi = container_of(cdev, struct gadget_info, cdev);
366 
367 	struct config_group *group = to_config_group(usb_func_ci);
368 	struct usb_function_instance *fi = container_of(group,
369 			struct usb_function_instance, group);
370 	struct usb_function_instance *a_fi;
371 	struct usb_function *f;
372 	int ret;
373 
374 	mutex_lock(&gi->lock);
375 	/*
376 	 * Make sure this function is from within our _this_ gadget and not
377 	 * from another gadget or a random directory.
378 	 * Also a function instance can only be linked once.
379 	 */
380 	list_for_each_entry(a_fi, &gi->available_func, cfs_list) {
381 		if (a_fi == fi)
382 			break;
383 	}
384 	if (a_fi != fi) {
385 		ret = -EINVAL;
386 		goto out;
387 	}
388 
389 	list_for_each_entry(f, &cfg->func_list, list) {
390 		if (f->fi == fi) {
391 			ret = -EEXIST;
392 			goto out;
393 		}
394 	}
395 
396 	f = usb_get_function(fi);
397 	if (IS_ERR(f)) {
398 		ret = PTR_ERR(f);
399 		goto out;
400 	}
401 
402 	/* stash the function until we bind it to the gadget */
403 	list_add_tail(&f->list, &cfg->func_list);
404 	ret = 0;
405 out:
406 	mutex_unlock(&gi->lock);
407 	return ret;
408 }
409 
410 static int config_usb_cfg_unlink(
411 	struct config_item *usb_cfg_ci,
412 	struct config_item *usb_func_ci)
413 {
414 	struct config_usb_cfg *cfg = to_config_usb_cfg(usb_cfg_ci);
415 	struct usb_composite_dev *cdev = cfg->c.cdev;
416 	struct gadget_info *gi = container_of(cdev, struct gadget_info, cdev);
417 
418 	struct config_group *group = to_config_group(usb_func_ci);
419 	struct usb_function_instance *fi = container_of(group,
420 			struct usb_function_instance, group);
421 	struct usb_function *f;
422 
423 	/*
424 	 * ideally I would like to forbid to unlink functions while a gadget is
425 	 * bound to an UDC. Since this isn't possible at the moment, we simply
426 	 * force an unbind, the function is available here and then we can
427 	 * remove the function.
428 	 */
429 	mutex_lock(&gi->lock);
430 	if (gi->udc_name)
431 		unregister_gadget(gi);
432 	WARN_ON(gi->udc_name);
433 
434 	list_for_each_entry(f, &cfg->func_list, list) {
435 		if (f->fi == fi) {
436 			list_del(&f->list);
437 			usb_put_function(f);
438 			mutex_unlock(&gi->lock);
439 			return 0;
440 		}
441 	}
442 	mutex_unlock(&gi->lock);
443 	WARN(1, "Unable to locate function to unbind\n");
444 	return 0;
445 }
446 
447 CONFIGFS_ATTR_OPS(config_usb_cfg);
448 
449 static struct configfs_item_operations gadget_config_item_ops = {
450 	.release                = gadget_config_attr_release,
451 	.show_attribute         = config_usb_cfg_attr_show,
452 	.store_attribute        = config_usb_cfg_attr_store,
453 	.allow_link             = config_usb_cfg_link,
454 	.drop_link              = config_usb_cfg_unlink,
455 };
456 
457 
458 static ssize_t gadget_config_desc_MaxPower_show(struct config_usb_cfg *cfg,
459 		char *page)
460 {
461 	return sprintf(page, "%u\n", cfg->c.MaxPower);
462 }
463 
464 static ssize_t gadget_config_desc_MaxPower_store(struct config_usb_cfg *cfg,
465 		const char *page, size_t len)
466 {
467 	u16 val;
468 	int ret;
469 	ret = kstrtou16(page, 0, &val);
470 	if (ret)
471 		return ret;
472 	if (DIV_ROUND_UP(val, 8) > 0xff)
473 		return -ERANGE;
474 	cfg->c.MaxPower = val;
475 	return len;
476 }
477 
478 static ssize_t gadget_config_desc_bmAttributes_show(struct config_usb_cfg *cfg,
479 		char *page)
480 {
481 	return sprintf(page, "0x%02x\n", cfg->c.bmAttributes);
482 }
483 
484 static ssize_t gadget_config_desc_bmAttributes_store(struct config_usb_cfg *cfg,
485 		const char *page, size_t len)
486 {
487 	u8 val;
488 	int ret;
489 	ret = kstrtou8(page, 0, &val);
490 	if (ret)
491 		return ret;
492 	if (!(val & USB_CONFIG_ATT_ONE))
493 		return -EINVAL;
494 	if (val & ~(USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER |
495 				USB_CONFIG_ATT_WAKEUP))
496 		return -EINVAL;
497 	cfg->c.bmAttributes = val;
498 	return len;
499 }
500 
501 #define CFG_CONFIG_DESC_ITEM_ATTR(name)	\
502 	static struct config_usb_cfg_attribute gadget_usb_cfg_##name = \
503 		__CONFIGFS_ATTR(name,  S_IRUGO | S_IWUSR,		\
504 				gadget_config_desc_##name##_show,	\
505 				gadget_config_desc_##name##_store)
506 
507 CFG_CONFIG_DESC_ITEM_ATTR(MaxPower);
508 CFG_CONFIG_DESC_ITEM_ATTR(bmAttributes);
509 
510 static struct configfs_attribute *gadget_config_attrs[] = {
511 	&gadget_usb_cfg_MaxPower.attr,
512 	&gadget_usb_cfg_bmAttributes.attr,
513 	NULL,
514 };
515 
516 static struct config_item_type gadget_config_type = {
517 	.ct_item_ops	= &gadget_config_item_ops,
518 	.ct_attrs	= gadget_config_attrs,
519 	.ct_owner	= THIS_MODULE,
520 };
521 
522 static struct config_item_type gadget_root_type = {
523 	.ct_item_ops	= &gadget_root_item_ops,
524 	.ct_attrs	= gadget_root_attrs,
525 	.ct_owner	= THIS_MODULE,
526 };
527 
528 static void composite_init_dev(struct usb_composite_dev *cdev)
529 {
530 	spin_lock_init(&cdev->lock);
531 	INIT_LIST_HEAD(&cdev->configs);
532 	INIT_LIST_HEAD(&cdev->gstrings);
533 }
534 
535 static struct config_group *function_make(
536 		struct config_group *group,
537 		const char *name)
538 {
539 	struct gadget_info *gi;
540 	struct usb_function_instance *fi;
541 	char buf[MAX_NAME_LEN];
542 	char *func_name;
543 	char *instance_name;
544 	int ret;
545 
546 	ret = snprintf(buf, MAX_NAME_LEN, "%s", name);
547 	if (ret >= MAX_NAME_LEN)
548 		return ERR_PTR(-ENAMETOOLONG);
549 
550 	func_name = buf;
551 	instance_name = strchr(func_name, '.');
552 	if (!instance_name) {
553 		pr_err("Unable to locate . in FUNC.INSTANCE\n");
554 		return ERR_PTR(-EINVAL);
555 	}
556 	*instance_name = '\0';
557 	instance_name++;
558 
559 	fi = usb_get_function_instance(func_name);
560 	if (IS_ERR(fi))
561 		return ERR_CAST(fi);
562 
563 	ret = config_item_set_name(&fi->group.cg_item, name);
564 	if (ret) {
565 		usb_put_function_instance(fi);
566 		return ERR_PTR(ret);
567 	}
568 	if (fi->set_inst_name) {
569 		ret = fi->set_inst_name(fi, instance_name);
570 		if (ret) {
571 			usb_put_function_instance(fi);
572 			return ERR_PTR(ret);
573 		}
574 	}
575 
576 	gi = container_of(group, struct gadget_info, functions_group);
577 
578 	mutex_lock(&gi->lock);
579 	list_add_tail(&fi->cfs_list, &gi->available_func);
580 	mutex_unlock(&gi->lock);
581 	return &fi->group;
582 }
583 
584 static void function_drop(
585 		struct config_group *group,
586 		struct config_item *item)
587 {
588 	struct usb_function_instance *fi = to_usb_function_instance(item);
589 	struct gadget_info *gi;
590 
591 	gi = container_of(group, struct gadget_info, functions_group);
592 
593 	mutex_lock(&gi->lock);
594 	list_del(&fi->cfs_list);
595 	mutex_unlock(&gi->lock);
596 	config_item_put(item);
597 }
598 
599 static struct configfs_group_operations functions_ops = {
600 	.make_group     = &function_make,
601 	.drop_item      = &function_drop,
602 };
603 
604 static struct config_item_type functions_type = {
605 	.ct_group_ops   = &functions_ops,
606 	.ct_owner       = THIS_MODULE,
607 };
608 
609 CONFIGFS_ATTR_STRUCT(gadget_config_name);
610 GS_STRINGS_RW(gadget_config_name, configuration);
611 
612 static struct configfs_attribute *gadget_config_name_langid_attrs[] = {
613 	&gadget_config_name_configuration.attr,
614 	NULL,
615 };
616 
617 static void gadget_config_name_attr_release(struct config_item *item)
618 {
619 	struct gadget_config_name *cn = to_gadget_config_name(item);
620 
621 	kfree(cn->configuration);
622 
623 	list_del(&cn->list);
624 	kfree(cn);
625 }
626 
627 USB_CONFIG_STRING_RW_OPS(gadget_config_name);
628 USB_CONFIG_STRINGS_LANG(gadget_config_name, config_usb_cfg);
629 
630 static struct config_group *config_desc_make(
631 		struct config_group *group,
632 		const char *name)
633 {
634 	struct gadget_info *gi;
635 	struct config_usb_cfg *cfg;
636 	char buf[MAX_NAME_LEN];
637 	char *num_str;
638 	u8 num;
639 	int ret;
640 
641 	gi = container_of(group, struct gadget_info, configs_group);
642 	ret = snprintf(buf, MAX_NAME_LEN, "%s", name);
643 	if (ret >= MAX_NAME_LEN)
644 		return ERR_PTR(-ENAMETOOLONG);
645 
646 	num_str = strchr(buf, '.');
647 	if (!num_str) {
648 		pr_err("Unable to locate . in name.bConfigurationValue\n");
649 		return ERR_PTR(-EINVAL);
650 	}
651 
652 	*num_str = '\0';
653 	num_str++;
654 
655 	if (!strlen(buf))
656 		return ERR_PTR(-EINVAL);
657 
658 	ret = kstrtou8(num_str, 0, &num);
659 	if (ret)
660 		return ERR_PTR(ret);
661 
662 	cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
663 	if (!cfg)
664 		return ERR_PTR(-ENOMEM);
665 	cfg->c.label = kstrdup(buf, GFP_KERNEL);
666 	if (!cfg->c.label) {
667 		ret = -ENOMEM;
668 		goto err;
669 	}
670 	cfg->c.bConfigurationValue = num;
671 	cfg->c.MaxPower = CONFIG_USB_GADGET_VBUS_DRAW;
672 	cfg->c.bmAttributes = USB_CONFIG_ATT_ONE;
673 	INIT_LIST_HEAD(&cfg->string_list);
674 	INIT_LIST_HEAD(&cfg->func_list);
675 
676 	cfg->group.default_groups = cfg->default_groups;
677 	cfg->default_groups[0] = &cfg->strings_group;
678 
679 	config_group_init_type_name(&cfg->group, name,
680 				&gadget_config_type);
681 	config_group_init_type_name(&cfg->strings_group, "strings",
682 			&gadget_config_name_strings_type);
683 
684 	ret = usb_add_config_only(&gi->cdev, &cfg->c);
685 	if (ret)
686 		goto err;
687 
688 	return &cfg->group;
689 err:
690 	kfree(cfg->c.label);
691 	kfree(cfg);
692 	return ERR_PTR(ret);
693 }
694 
695 static void config_desc_drop(
696 		struct config_group *group,
697 		struct config_item *item)
698 {
699 	config_item_put(item);
700 }
701 
702 static struct configfs_group_operations config_desc_ops = {
703 	.make_group     = &config_desc_make,
704 	.drop_item      = &config_desc_drop,
705 };
706 
707 static struct config_item_type config_desc_type = {
708 	.ct_group_ops   = &config_desc_ops,
709 	.ct_owner       = THIS_MODULE,
710 };
711 
712 CONFIGFS_ATTR_STRUCT(gadget_strings);
713 GS_STRINGS_RW(gadget_strings, manufacturer);
714 GS_STRINGS_RW(gadget_strings, product);
715 GS_STRINGS_RW(gadget_strings, serialnumber);
716 
717 static struct configfs_attribute *gadget_strings_langid_attrs[] = {
718 	&gadget_strings_manufacturer.attr,
719 	&gadget_strings_product.attr,
720 	&gadget_strings_serialnumber.attr,
721 	NULL,
722 };
723 
724 static void gadget_strings_attr_release(struct config_item *item)
725 {
726 	struct gadget_strings *gs = to_gadget_strings(item);
727 
728 	kfree(gs->manufacturer);
729 	kfree(gs->product);
730 	kfree(gs->serialnumber);
731 
732 	list_del(&gs->list);
733 	kfree(gs);
734 }
735 
736 USB_CONFIG_STRING_RW_OPS(gadget_strings);
737 USB_CONFIG_STRINGS_LANG(gadget_strings, gadget_info);
738 
739 static int configfs_do_nothing(struct usb_composite_dev *cdev)
740 {
741 	WARN_ON(1);
742 	return -EINVAL;
743 }
744 
745 int composite_dev_prepare(struct usb_composite_driver *composite,
746 		struct usb_composite_dev *dev);
747 
748 static void purge_configs_funcs(struct gadget_info *gi)
749 {
750 	struct usb_configuration	*c;
751 
752 	list_for_each_entry(c, &gi->cdev.configs, list) {
753 		struct usb_function *f, *tmp;
754 		struct config_usb_cfg *cfg;
755 
756 		cfg = container_of(c, struct config_usb_cfg, c);
757 
758 		list_for_each_entry_safe(f, tmp, &c->functions, list) {
759 
760 			list_move_tail(&f->list, &cfg->func_list);
761 			if (f->unbind) {
762 				dev_err(&gi->cdev.gadget->dev, "unbind function"
763 						" '%s'/%p\n", f->name, f);
764 				f->unbind(c, f);
765 			}
766 		}
767 		c->next_interface_id = 0;
768 		c->superspeed = 0;
769 		c->highspeed = 0;
770 		c->fullspeed = 0;
771 	}
772 }
773 
774 static int configfs_composite_bind(struct usb_gadget *gadget,
775 		struct usb_gadget_driver *gdriver)
776 {
777 	struct usb_composite_driver     *composite = to_cdriver(gdriver);
778 	struct gadget_info		*gi = container_of(composite,
779 						struct gadget_info, composite);
780 	struct usb_composite_dev	*cdev = &gi->cdev;
781 	struct usb_configuration	*c;
782 	struct usb_string		*s;
783 	unsigned			i;
784 	int				ret;
785 
786 	/* the gi->lock is hold by the caller */
787 	cdev->gadget = gadget;
788 	set_gadget_data(gadget, cdev);
789 	ret = composite_dev_prepare(composite, cdev);
790 	if (ret)
791 		return ret;
792 	/* and now the gadget bind */
793 	ret = -EINVAL;
794 
795 	if (list_empty(&gi->cdev.configs)) {
796 		pr_err("Need atleast one configuration in %s.\n",
797 				gi->composite.name);
798 		goto err_comp_cleanup;
799 	}
800 
801 
802 	list_for_each_entry(c, &gi->cdev.configs, list) {
803 		struct config_usb_cfg *cfg;
804 
805 		cfg = container_of(c, struct config_usb_cfg, c);
806 		if (list_empty(&cfg->func_list)) {
807 			pr_err("Config %s/%d of %s needs atleast one function.\n",
808 			      c->label, c->bConfigurationValue,
809 			      gi->composite.name);
810 			goto err_comp_cleanup;
811 		}
812 	}
813 
814 	/* init all strings */
815 	if (!list_empty(&gi->string_list)) {
816 		struct gadget_strings *gs;
817 
818 		i = 0;
819 		list_for_each_entry(gs, &gi->string_list, list) {
820 
821 			gi->gstrings[i] = &gs->stringtab_dev;
822 			gs->stringtab_dev.strings = gs->strings;
823 			gs->strings[USB_GADGET_MANUFACTURER_IDX].s =
824 				gs->manufacturer;
825 			gs->strings[USB_GADGET_PRODUCT_IDX].s = gs->product;
826 			gs->strings[USB_GADGET_SERIAL_IDX].s = gs->serialnumber;
827 			i++;
828 		}
829 		gi->gstrings[i] = NULL;
830 		s = usb_gstrings_attach(&gi->cdev, gi->gstrings,
831 				USB_GADGET_FIRST_AVAIL_IDX);
832 		if (IS_ERR(s)) {
833 			ret = PTR_ERR(s);
834 			goto err_comp_cleanup;
835 		}
836 
837 		gi->cdev.desc.iManufacturer = s[USB_GADGET_MANUFACTURER_IDX].id;
838 		gi->cdev.desc.iProduct = s[USB_GADGET_PRODUCT_IDX].id;
839 		gi->cdev.desc.iSerialNumber = s[USB_GADGET_SERIAL_IDX].id;
840 	}
841 
842 	/* Go through all configs, attach all functions */
843 	list_for_each_entry(c, &gi->cdev.configs, list) {
844 		struct config_usb_cfg *cfg;
845 		struct usb_function *f;
846 		struct usb_function *tmp;
847 		struct gadget_config_name *cn;
848 
849 		cfg = container_of(c, struct config_usb_cfg, c);
850 		if (!list_empty(&cfg->string_list)) {
851 			i = 0;
852 			list_for_each_entry(cn, &cfg->string_list, list) {
853 				cfg->gstrings[i] = &cn->stringtab_dev;
854 				cn->stringtab_dev.strings = &cn->strings;
855 				cn->strings.s = cn->configuration;
856 				i++;
857 			}
858 			cfg->gstrings[i] = NULL;
859 			s = usb_gstrings_attach(&gi->cdev, cfg->gstrings, 1);
860 			if (IS_ERR(s)) {
861 				ret = PTR_ERR(s);
862 				goto err_comp_cleanup;
863 			}
864 			c->iConfiguration = s[0].id;
865 		}
866 
867 		list_for_each_entry_safe(f, tmp, &cfg->func_list, list) {
868 			list_del(&f->list);
869 			ret = usb_add_function(c, f);
870 			if (ret) {
871 				list_add(&f->list, &cfg->func_list);
872 				goto err_purge_funcs;
873 			}
874 		}
875 		usb_ep_autoconfig_reset(cdev->gadget);
876 	}
877 	usb_ep_autoconfig_reset(cdev->gadget);
878 	return 0;
879 
880 err_purge_funcs:
881 	purge_configs_funcs(gi);
882 err_comp_cleanup:
883 	composite_dev_cleanup(cdev);
884 	return ret;
885 }
886 
887 static void configfs_composite_unbind(struct usb_gadget *gadget)
888 {
889 	struct usb_composite_dev	*cdev;
890 	struct gadget_info		*gi;
891 
892 	/* the gi->lock is hold by the caller */
893 
894 	cdev = get_gadget_data(gadget);
895 	gi = container_of(cdev, struct gadget_info, cdev);
896 
897 	purge_configs_funcs(gi);
898 	composite_dev_cleanup(cdev);
899 	usb_ep_autoconfig_reset(cdev->gadget);
900 	cdev->gadget = NULL;
901 	set_gadget_data(gadget, NULL);
902 }
903 
904 static const struct usb_gadget_driver configfs_driver_template = {
905 	.bind           = configfs_composite_bind,
906 	.unbind         = configfs_composite_unbind,
907 
908 	.setup          = composite_setup,
909 	.disconnect     = composite_disconnect,
910 
911 	.max_speed	= USB_SPEED_SUPER,
912 	.driver = {
913 		.owner          = THIS_MODULE,
914 		.name		= "configfs-gadget",
915 	},
916 };
917 
918 static struct config_group *gadgets_make(
919 		struct config_group *group,
920 		const char *name)
921 {
922 	struct gadget_info *gi;
923 
924 	gi = kzalloc(sizeof(*gi), GFP_KERNEL);
925 	if (!gi)
926 		return ERR_PTR(-ENOMEM);
927 
928 	gi->group.default_groups = gi->default_groups;
929 	gi->group.default_groups[0] = &gi->functions_group;
930 	gi->group.default_groups[1] = &gi->configs_group;
931 	gi->group.default_groups[2] = &gi->strings_group;
932 
933 	config_group_init_type_name(&gi->functions_group, "functions",
934 			&functions_type);
935 	config_group_init_type_name(&gi->configs_group, "configs",
936 			&config_desc_type);
937 	config_group_init_type_name(&gi->strings_group, "strings",
938 			&gadget_strings_strings_type);
939 
940 	gi->composite.bind = configfs_do_nothing;
941 	gi->composite.unbind = configfs_do_nothing;
942 	gi->composite.suspend = NULL;
943 	gi->composite.resume = NULL;
944 	gi->composite.max_speed = USB_SPEED_SUPER;
945 
946 	mutex_init(&gi->lock);
947 	INIT_LIST_HEAD(&gi->string_list);
948 	INIT_LIST_HEAD(&gi->available_func);
949 
950 	composite_init_dev(&gi->cdev);
951 	gi->cdev.desc.bLength = USB_DT_DEVICE_SIZE;
952 	gi->cdev.desc.bDescriptorType = USB_DT_DEVICE;
953 	gi->cdev.desc.bcdDevice = cpu_to_le16(get_default_bcdDevice());
954 
955 	gi->composite.gadget_driver = configfs_driver_template;
956 
957 	gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL);
958 	gi->composite.name = gi->composite.gadget_driver.function;
959 
960 	if (!gi->composite.gadget_driver.function)
961 		goto err;
962 
963 #ifdef CONFIG_USB_OTG
964 	gi->otg.bLength = sizeof(struct usb_otg_descriptor);
965 	gi->otg.bDescriptorType = USB_DT_OTG;
966 	gi->otg.bmAttributes = USB_OTG_SRP | USB_OTG_HNP;
967 #endif
968 
969 	config_group_init_type_name(&gi->group, name,
970 				&gadget_root_type);
971 	return &gi->group;
972 err:
973 	kfree(gi);
974 	return ERR_PTR(-ENOMEM);
975 }
976 
977 static void gadgets_drop(struct config_group *group, struct config_item *item)
978 {
979 	config_item_put(item);
980 }
981 
982 static struct configfs_group_operations gadgets_ops = {
983 	.make_group     = &gadgets_make,
984 	.drop_item      = &gadgets_drop,
985 };
986 
987 static struct config_item_type gadgets_type = {
988 	.ct_group_ops   = &gadgets_ops,
989 	.ct_owner       = THIS_MODULE,
990 };
991 
992 static struct configfs_subsystem gadget_subsys = {
993 	.su_group = {
994 		.cg_item = {
995 			.ci_namebuf = "usb_gadget",
996 			.ci_type = &gadgets_type,
997 		},
998 	},
999 	.su_mutex = __MUTEX_INITIALIZER(gadget_subsys.su_mutex),
1000 };
1001 
1002 void unregister_gadget_item(struct config_item *item)
1003 {
1004 	struct gadget_info *gi = to_gadget_info(item);
1005 
1006 	unregister_gadget(gi);
1007 }
1008 EXPORT_SYMBOL(unregister_gadget_item);
1009 
1010 static int __init gadget_cfs_init(void)
1011 {
1012 	int ret;
1013 
1014 	config_group_init(&gadget_subsys.su_group);
1015 
1016 	ret = configfs_register_subsystem(&gadget_subsys);
1017 	return ret;
1018 }
1019 module_init(gadget_cfs_init);
1020 
1021 static void __exit gadget_cfs_exit(void)
1022 {
1023 	configfs_unregister_subsystem(&gadget_subsys);
1024 }
1025 module_exit(gadget_cfs_exit);
1026