xref: /linux/drivers/usb/gadget/legacy/g_ffs.c (revision be709d48329a500621d2a05835283150ae137b45) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * g_ffs.c -- user mode file system API for USB composite function controllers
4  *
5  * Copyright (C) 2010 Samsung Electronics
6  * Author: Michal Nazarewicz <mina86@mina86.com>
7  */
8 
9 #define pr_fmt(fmt) "g_ffs: " fmt
10 
11 #include <linux/module.h>
12 
13 #if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
14 #include <linux/netdevice.h>
15 
16 #  if defined USB_ETH_RNDIS
17 #    undef USB_ETH_RNDIS
18 #  endif
19 #  ifdef CONFIG_USB_FUNCTIONFS_RNDIS
20 #    define USB_ETH_RNDIS y
21 #  endif
22 
23 #  include "u_ecm.h"
24 #  include "u_gether.h"
25 #  ifdef USB_ETH_RNDIS
26 #    include "u_rndis.h"
27 #    include "rndis.h"
28 #  endif
29 #  include "u_ether.h"
30 
31 USB_ETHERNET_MODULE_PARAMETERS();
32 
33 #  ifdef CONFIG_USB_FUNCTIONFS_ETH
34 static int eth_bind_config(struct usb_configuration *c);
35 static struct usb_function_instance *fi_ecm;
36 static struct usb_function *f_ecm;
37 static struct usb_function_instance *fi_geth;
38 static struct usb_function *f_geth;
39 #  endif
40 #  ifdef CONFIG_USB_FUNCTIONFS_RNDIS
41 static int bind_rndis_config(struct usb_configuration *c);
42 static struct usb_function_instance *fi_rndis;
43 static struct usb_function *f_rndis;
44 #  endif
45 #endif
46 
47 #include "u_fs.h"
48 
49 #define DRIVER_NAME	"g_ffs"
50 #define DRIVER_DESC	"USB Function Filesystem"
51 #define DRIVER_VERSION	"24 Aug 2004"
52 
53 MODULE_DESCRIPTION(DRIVER_DESC);
54 MODULE_AUTHOR("Michal Nazarewicz");
55 MODULE_LICENSE("GPL");
56 
57 #define GFS_VENDOR_ID	0x1d6b	/* Linux Foundation */
58 #define GFS_PRODUCT_ID	0x0105	/* FunctionFS Gadget */
59 
60 #define GFS_MAX_DEVS	10
61 
62 USB_GADGET_COMPOSITE_OPTIONS();
63 
64 static struct usb_device_descriptor gfs_dev_desc = {
65 	.bLength		= sizeof gfs_dev_desc,
66 	.bDescriptorType	= USB_DT_DEVICE,
67 
68 	/* .bcdUSB = DYNAMIC */
69 	.bDeviceClass		= USB_CLASS_PER_INTERFACE,
70 
71 	.idVendor		= cpu_to_le16(GFS_VENDOR_ID),
72 	.idProduct		= cpu_to_le16(GFS_PRODUCT_ID),
73 };
74 
75 static char *func_names[GFS_MAX_DEVS];
76 static unsigned int func_num;
77 
78 module_param_named(bDeviceClass,    gfs_dev_desc.bDeviceClass,    byte,   0644);
79 MODULE_PARM_DESC(bDeviceClass, "USB Device class");
80 module_param_named(bDeviceSubClass, gfs_dev_desc.bDeviceSubClass, byte,   0644);
81 MODULE_PARM_DESC(bDeviceSubClass, "USB Device subclass");
82 module_param_named(bDeviceProtocol, gfs_dev_desc.bDeviceProtocol, byte,   0644);
83 MODULE_PARM_DESC(bDeviceProtocol, "USB Device protocol");
84 module_param_array_named(functions, func_names, charp, &func_num, 0);
85 MODULE_PARM_DESC(functions, "USB Functions list");
86 
87 static const struct usb_descriptor_header *gfs_otg_desc[2];
88 
89 /* String IDs are assigned dynamically */
90 static struct usb_string gfs_strings[] = {
91 	[USB_GADGET_MANUFACTURER_IDX].s = "",
92 	[USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
93 	[USB_GADGET_SERIAL_IDX].s = "",
94 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
95 	{ .s = "FunctionFS + RNDIS" },
96 #endif
97 #ifdef CONFIG_USB_FUNCTIONFS_ETH
98 	{ .s = "FunctionFS + ECM" },
99 #endif
100 #ifdef CONFIG_USB_FUNCTIONFS_GENERIC
101 	{ .s = "FunctionFS" },
102 #endif
103 	{  } /* end of list */
104 };
105 
106 static struct usb_gadget_strings *gfs_dev_strings[] = {
107 	&(struct usb_gadget_strings) {
108 		.language	= 0x0409,	/* en-us */
109 		.strings	= gfs_strings,
110 	},
111 	NULL,
112 };
113 
114 struct gfs_configuration {
115 	struct usb_configuration c;
116 	int (*eth)(struct usb_configuration *c);
117 	int num;
118 };
119 
120 static struct gfs_configuration gfs_configurations[] = {
121 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
122 	{
123 		.eth		= bind_rndis_config,
124 	},
125 #endif
126 
127 #ifdef CONFIG_USB_FUNCTIONFS_ETH
128 	{
129 		.eth		= eth_bind_config,
130 	},
131 #endif
132 
133 #ifdef CONFIG_USB_FUNCTIONFS_GENERIC
134 	{
135 	},
136 #endif
137 };
138 
139 static void *functionfs_acquire_dev(struct ffs_dev *dev);
140 static void functionfs_release_dev(struct ffs_dev *dev);
141 static int functionfs_ready_callback(struct ffs_data *ffs);
142 static void functionfs_closed_callback(struct ffs_data *ffs);
143 static int gfs_bind(struct usb_composite_dev *cdev);
144 static int gfs_unbind(struct usb_composite_dev *cdev);
145 static int gfs_do_config(struct usb_configuration *c);
146 
147 
148 static struct usb_composite_driver gfs_driver = {
149 	.name		= DRIVER_NAME,
150 	.dev		= &gfs_dev_desc,
151 	.strings	= gfs_dev_strings,
152 	.max_speed	= USB_SPEED_HIGH,
153 	.bind		= gfs_bind,
154 	.unbind		= gfs_unbind,
155 };
156 
157 static unsigned int missing_funcs;
158 static bool gfs_registered;
159 static bool gfs_single_func;
160 static struct usb_function_instance **fi_ffs;
161 static struct usb_function **f_ffs[] = {
162 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
163 	NULL,
164 #endif
165 
166 #ifdef CONFIG_USB_FUNCTIONFS_ETH
167 	NULL,
168 #endif
169 
170 #ifdef CONFIG_USB_FUNCTIONFS_GENERIC
171 	NULL,
172 #endif
173 };
174 
175 #define N_CONF ARRAY_SIZE(f_ffs)
176 
177 static int __init gfs_init(void)
178 {
179 	struct f_fs_opts *opts;
180 	int i;
181 	int ret = 0;
182 
183 	ENTER();
184 
185 	if (func_num < 2) {
186 		gfs_single_func = true;
187 		func_num = 1;
188 	}
189 
190 	/*
191 	 * Allocate in one chunk for easier maintenance
192 	 */
193 	f_ffs[0] = kcalloc(func_num * N_CONF, sizeof(*f_ffs), GFP_KERNEL);
194 	if (!f_ffs[0]) {
195 		ret = -ENOMEM;
196 		goto no_func;
197 	}
198 	for (i = 1; i < N_CONF; ++i)
199 		f_ffs[i] = f_ffs[0] + i * func_num;
200 
201 	fi_ffs = kcalloc(func_num, sizeof(*fi_ffs), GFP_KERNEL);
202 	if (!fi_ffs) {
203 		ret = -ENOMEM;
204 		goto no_func;
205 	}
206 
207 	for (i = 0; i < func_num; i++) {
208 		fi_ffs[i] = usb_get_function_instance("ffs");
209 		if (IS_ERR(fi_ffs[i])) {
210 			ret = PTR_ERR(fi_ffs[i]);
211 			--i;
212 			goto no_dev;
213 		}
214 		opts = to_f_fs_opts(fi_ffs[i]);
215 		if (gfs_single_func)
216 			ret = ffs_single_dev(opts->dev);
217 		else
218 			ret = ffs_name_dev(opts->dev, func_names[i]);
219 		if (ret)
220 			goto no_dev;
221 		opts->dev->ffs_ready_callback = functionfs_ready_callback;
222 		opts->dev->ffs_closed_callback = functionfs_closed_callback;
223 		opts->dev->ffs_acquire_dev_callback = functionfs_acquire_dev;
224 		opts->dev->ffs_release_dev_callback = functionfs_release_dev;
225 		opts->no_configfs = true;
226 	}
227 
228 	missing_funcs = func_num;
229 
230 	return 0;
231 no_dev:
232 	while (i >= 0)
233 		usb_put_function_instance(fi_ffs[i--]);
234 	kfree(fi_ffs);
235 no_func:
236 	kfree(f_ffs[0]);
237 	return ret;
238 }
239 module_init(gfs_init);
240 
241 static void __exit gfs_exit(void)
242 {
243 	int i;
244 
245 	ENTER();
246 
247 	if (gfs_registered)
248 		usb_composite_unregister(&gfs_driver);
249 	gfs_registered = false;
250 
251 	kfree(f_ffs[0]);
252 
253 	for (i = 0; i < func_num; i++)
254 		usb_put_function_instance(fi_ffs[i]);
255 
256 	kfree(fi_ffs);
257 }
258 module_exit(gfs_exit);
259 
260 static void *functionfs_acquire_dev(struct ffs_dev *dev)
261 {
262 	if (!try_module_get(THIS_MODULE))
263 		return ERR_PTR(-ENOENT);
264 
265 	return NULL;
266 }
267 
268 static void functionfs_release_dev(struct ffs_dev *dev)
269 {
270 	module_put(THIS_MODULE);
271 }
272 
273 /*
274  * The caller of this function takes ffs_lock
275  */
276 static int functionfs_ready_callback(struct ffs_data *ffs)
277 {
278 	int ret = 0;
279 
280 	if (--missing_funcs)
281 		return 0;
282 
283 	if (gfs_registered)
284 		return -EBUSY;
285 
286 	gfs_registered = true;
287 
288 	ret = usb_composite_probe(&gfs_driver);
289 	if (unlikely(ret < 0)) {
290 		++missing_funcs;
291 		gfs_registered = false;
292 	}
293 
294 	return ret;
295 }
296 
297 /*
298  * The caller of this function takes ffs_lock
299  */
300 static void functionfs_closed_callback(struct ffs_data *ffs)
301 {
302 	missing_funcs++;
303 
304 	if (gfs_registered)
305 		usb_composite_unregister(&gfs_driver);
306 	gfs_registered = false;
307 }
308 
309 /*
310  * It is assumed that gfs_bind is called from a context where ffs_lock is held
311  */
312 static int gfs_bind(struct usb_composite_dev *cdev)
313 {
314 #if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
315 	struct net_device *net;
316 #endif
317 	int ret, i;
318 
319 	ENTER();
320 
321 	if (missing_funcs)
322 		return -ENODEV;
323 #if defined CONFIG_USB_FUNCTIONFS_ETH
324 	if (can_support_ecm(cdev->gadget)) {
325 		struct f_ecm_opts *ecm_opts;
326 
327 		fi_ecm = usb_get_function_instance("ecm");
328 		if (IS_ERR(fi_ecm))
329 			return PTR_ERR(fi_ecm);
330 		ecm_opts = container_of(fi_ecm, struct f_ecm_opts, func_inst);
331 		net = ecm_opts->net;
332 	} else {
333 		struct f_gether_opts *geth_opts;
334 
335 		fi_geth = usb_get_function_instance("geth");
336 		if (IS_ERR(fi_geth))
337 			return PTR_ERR(fi_geth);
338 		geth_opts = container_of(fi_geth, struct f_gether_opts,
339 					 func_inst);
340 		net = geth_opts->net;
341 	}
342 #endif
343 
344 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
345 	{
346 		fi_rndis = usb_get_function_instance("rndis");
347 		if (IS_ERR(fi_rndis)) {
348 			ret = PTR_ERR(fi_rndis);
349 			goto error;
350 		}
351 #ifndef CONFIG_USB_FUNCTIONFS_ETH
352 		net = container_of(fi_rndis, struct f_rndis_opts,
353 				   func_inst)->net;
354 #endif
355 	}
356 #endif
357 
358 #if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
359 	gether_set_qmult(net, qmult);
360 	if (!gether_set_host_addr(net, host_addr))
361 		pr_info("using host ethernet address: %s", host_addr);
362 	if (!gether_set_dev_addr(net, dev_addr))
363 		pr_info("using self ethernet address: %s", dev_addr);
364 #endif
365 
366 #if defined CONFIG_USB_FUNCTIONFS_RNDIS && defined CONFIG_USB_FUNCTIONFS_ETH
367 	gether_set_gadget(net, cdev->gadget);
368 	ret = gether_register_netdev(net);
369 	if (ret)
370 		goto error_rndis;
371 
372 	if (can_support_ecm(cdev->gadget)) {
373 		struct f_ecm_opts *ecm_opts;
374 
375 		ecm_opts = container_of(fi_ecm, struct f_ecm_opts, func_inst);
376 		ecm_opts->bound = true;
377 	} else {
378 		struct f_gether_opts *geth_opts;
379 
380 		geth_opts = container_of(fi_geth, struct f_gether_opts,
381 					 func_inst);
382 		geth_opts->bound = true;
383 	}
384 
385 	rndis_borrow_net(fi_rndis, net);
386 #endif
387 
388 	/* TODO: gstrings_attach? */
389 	ret = usb_string_ids_tab(cdev, gfs_strings);
390 	if (unlikely(ret < 0))
391 		goto error_rndis;
392 	gfs_dev_desc.iProduct = gfs_strings[USB_GADGET_PRODUCT_IDX].id;
393 
394 	if (gadget_is_otg(cdev->gadget) && !gfs_otg_desc[0]) {
395 		struct usb_descriptor_header *usb_desc;
396 
397 		usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
398 		if (!usb_desc)
399 			goto error_rndis;
400 		usb_otg_descriptor_init(cdev->gadget, usb_desc);
401 		gfs_otg_desc[0] = usb_desc;
402 		gfs_otg_desc[1] = NULL;
403 	}
404 
405 	for (i = 0; i < ARRAY_SIZE(gfs_configurations); ++i) {
406 		struct gfs_configuration *c = gfs_configurations + i;
407 		int sid = USB_GADGET_FIRST_AVAIL_IDX + i;
408 
409 		c->c.label			= gfs_strings[sid].s;
410 		c->c.iConfiguration		= gfs_strings[sid].id;
411 		c->c.bConfigurationValue	= 1 + i;
412 		c->c.bmAttributes		= USB_CONFIG_ATT_SELFPOWER;
413 
414 		c->num = i;
415 
416 		ret = usb_add_config(cdev, &c->c, gfs_do_config);
417 		if (unlikely(ret < 0))
418 			goto error_unbind;
419 	}
420 	usb_composite_overwrite_options(cdev, &coverwrite);
421 	return 0;
422 
423 /* TODO */
424 error_unbind:
425 	kfree(gfs_otg_desc[0]);
426 	gfs_otg_desc[0] = NULL;
427 error_rndis:
428 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
429 	usb_put_function_instance(fi_rndis);
430 error:
431 #endif
432 #if defined CONFIG_USB_FUNCTIONFS_ETH
433 	if (can_support_ecm(cdev->gadget))
434 		usb_put_function_instance(fi_ecm);
435 	else
436 		usb_put_function_instance(fi_geth);
437 #endif
438 	return ret;
439 }
440 
441 /*
442  * It is assumed that gfs_unbind is called from a context where ffs_lock is held
443  */
444 static int gfs_unbind(struct usb_composite_dev *cdev)
445 {
446 	int i;
447 
448 	ENTER();
449 
450 
451 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
452 	usb_put_function(f_rndis);
453 	usb_put_function_instance(fi_rndis);
454 #endif
455 
456 #if defined CONFIG_USB_FUNCTIONFS_ETH
457 	if (can_support_ecm(cdev->gadget)) {
458 		usb_put_function(f_ecm);
459 		usb_put_function_instance(fi_ecm);
460 	} else {
461 		usb_put_function(f_geth);
462 		usb_put_function_instance(fi_geth);
463 	}
464 #endif
465 	for (i = 0; i < N_CONF * func_num; ++i)
466 		usb_put_function(*(f_ffs[0] + i));
467 
468 	kfree(gfs_otg_desc[0]);
469 	gfs_otg_desc[0] = NULL;
470 
471 	return 0;
472 }
473 
474 /*
475  * It is assumed that gfs_do_config is called from a context where
476  * ffs_lock is held
477  */
478 static int gfs_do_config(struct usb_configuration *c)
479 {
480 	struct gfs_configuration *gc =
481 		container_of(c, struct gfs_configuration, c);
482 	int i;
483 	int ret;
484 
485 	if (missing_funcs)
486 		return -ENODEV;
487 
488 	if (gadget_is_otg(c->cdev->gadget)) {
489 		c->descriptors = gfs_otg_desc;
490 		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
491 	}
492 
493 	if (gc->eth) {
494 		ret = gc->eth(c);
495 		if (unlikely(ret < 0))
496 			return ret;
497 	}
498 
499 	for (i = 0; i < func_num; i++) {
500 		f_ffs[gc->num][i] = usb_get_function(fi_ffs[i]);
501 		if (IS_ERR(f_ffs[gc->num][i])) {
502 			ret = PTR_ERR(f_ffs[gc->num][i]);
503 			goto error;
504 		}
505 		ret = usb_add_function(c, f_ffs[gc->num][i]);
506 		if (ret < 0) {
507 			usb_put_function(f_ffs[gc->num][i]);
508 			goto error;
509 		}
510 	}
511 
512 	/*
513 	 * After previous do_configs there may be some invalid
514 	 * pointers in c->interface array.  This happens every time
515 	 * a user space function with fewer interfaces than a user
516 	 * space function that was run before the new one is run.  The
517 	 * compasit's set_config() assumes that if there is no more
518 	 * then MAX_CONFIG_INTERFACES interfaces in a configuration
519 	 * then there is a NULL pointer after the last interface in
520 	 * c->interface array.  We need to make sure this is true.
521 	 */
522 	if (c->next_interface_id < ARRAY_SIZE(c->interface))
523 		c->interface[c->next_interface_id] = NULL;
524 
525 	return 0;
526 error:
527 	while (--i >= 0) {
528 		if (!IS_ERR(f_ffs[gc->num][i]))
529 			usb_remove_function(c, f_ffs[gc->num][i]);
530 		usb_put_function(f_ffs[gc->num][i]);
531 	}
532 	return ret;
533 }
534 
535 #ifdef CONFIG_USB_FUNCTIONFS_ETH
536 
537 static int eth_bind_config(struct usb_configuration *c)
538 {
539 	int status = 0;
540 
541 	if (can_support_ecm(c->cdev->gadget)) {
542 		f_ecm = usb_get_function(fi_ecm);
543 		if (IS_ERR(f_ecm))
544 			return PTR_ERR(f_ecm);
545 
546 		status = usb_add_function(c, f_ecm);
547 		if (status < 0)
548 			usb_put_function(f_ecm);
549 
550 	} else {
551 		f_geth = usb_get_function(fi_geth);
552 		if (IS_ERR(f_geth))
553 			return PTR_ERR(f_geth);
554 
555 		status = usb_add_function(c, f_geth);
556 		if (status < 0)
557 			usb_put_function(f_geth);
558 	}
559 	return status;
560 }
561 
562 #endif
563 
564 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
565 
566 static int bind_rndis_config(struct usb_configuration *c)
567 {
568 	int status = 0;
569 
570 	f_rndis = usb_get_function(fi_rndis);
571 	if (IS_ERR(f_rndis))
572 		return PTR_ERR(f_rndis);
573 
574 	status = usb_add_function(c, f_rndis);
575 	if (status < 0)
576 		usb_put_function(f_rndis);
577 
578 	return status;
579 }
580 
581 #endif
582