xref: /linux/drivers/usb/gadget/legacy/g_ffs.c (revision 72bea132f3680ee51e7ed2cee62892b6f5121909) 
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_SUPER,
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 	if (func_num < 2) {
184 		gfs_single_func = true;
185 		func_num = 1;
186 	}
187 
188 	/*
189 	 * Allocate in one chunk for easier maintenance
190 	 */
191 	f_ffs[0] = kcalloc(func_num * N_CONF, sizeof(*f_ffs), GFP_KERNEL);
192 	if (!f_ffs[0]) {
193 		ret = -ENOMEM;
194 		goto no_func;
195 	}
196 	for (i = 1; i < N_CONF; ++i)
197 		f_ffs[i] = f_ffs[0] + i * func_num;
198 
199 	fi_ffs = kcalloc(func_num, sizeof(*fi_ffs), GFP_KERNEL);
200 	if (!fi_ffs) {
201 		ret = -ENOMEM;
202 		goto no_func;
203 	}
204 
205 	for (i = 0; i < func_num; i++) {
206 		fi_ffs[i] = usb_get_function_instance("ffs");
207 		if (IS_ERR(fi_ffs[i])) {
208 			ret = PTR_ERR(fi_ffs[i]);
209 			--i;
210 			goto no_dev;
211 		}
212 		opts = to_f_fs_opts(fi_ffs[i]);
213 		if (gfs_single_func)
214 			ret = ffs_single_dev(opts->dev);
215 		else
216 			ret = ffs_name_dev(opts->dev, func_names[i]);
217 		if (ret)
218 			goto no_dev;
219 		opts->dev->ffs_ready_callback = functionfs_ready_callback;
220 		opts->dev->ffs_closed_callback = functionfs_closed_callback;
221 		opts->dev->ffs_acquire_dev_callback = functionfs_acquire_dev;
222 		opts->dev->ffs_release_dev_callback = functionfs_release_dev;
223 		opts->no_configfs = true;
224 	}
225 
226 	missing_funcs = func_num;
227 
228 	return 0;
229 no_dev:
230 	while (i >= 0)
231 		usb_put_function_instance(fi_ffs[i--]);
232 	kfree(fi_ffs);
233 no_func:
234 	kfree(f_ffs[0]);
235 	return ret;
236 }
237 module_init(gfs_init);
238 
239 static void __exit gfs_exit(void)
240 {
241 	int i;
242 
243 	if (gfs_registered)
244 		usb_composite_unregister(&gfs_driver);
245 	gfs_registered = false;
246 
247 	kfree(f_ffs[0]);
248 
249 	for (i = 0; i < func_num; i++)
250 		usb_put_function_instance(fi_ffs[i]);
251 
252 	kfree(fi_ffs);
253 }
254 module_exit(gfs_exit);
255 
256 static void *functionfs_acquire_dev(struct ffs_dev *dev)
257 {
258 	if (!try_module_get(THIS_MODULE))
259 		return ERR_PTR(-ENOENT);
260 
261 	return NULL;
262 }
263 
264 static void functionfs_release_dev(struct ffs_dev *dev)
265 {
266 	module_put(THIS_MODULE);
267 }
268 
269 /*
270  * The caller of this function takes ffs_lock
271  */
272 static int functionfs_ready_callback(struct ffs_data *ffs)
273 {
274 	int ret = 0;
275 
276 	if (--missing_funcs)
277 		return 0;
278 
279 	if (gfs_registered)
280 		return -EBUSY;
281 
282 	gfs_registered = true;
283 
284 	ret = usb_composite_probe(&gfs_driver);
285 	if (unlikely(ret < 0)) {
286 		++missing_funcs;
287 		gfs_registered = false;
288 	}
289 
290 	return ret;
291 }
292 
293 /*
294  * The caller of this function takes ffs_lock
295  */
296 static void functionfs_closed_callback(struct ffs_data *ffs)
297 {
298 	missing_funcs++;
299 
300 	if (gfs_registered)
301 		usb_composite_unregister(&gfs_driver);
302 	gfs_registered = false;
303 }
304 
305 /*
306  * It is assumed that gfs_bind is called from a context where ffs_lock is held
307  */
308 static int gfs_bind(struct usb_composite_dev *cdev)
309 {
310 #if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
311 	struct net_device *net;
312 #endif
313 	int ret, i;
314 
315 	if (missing_funcs)
316 		return -ENODEV;
317 #if defined CONFIG_USB_FUNCTIONFS_ETH
318 	if (can_support_ecm(cdev->gadget)) {
319 		struct f_ecm_opts *ecm_opts;
320 
321 		fi_ecm = usb_get_function_instance("ecm");
322 		if (IS_ERR(fi_ecm))
323 			return PTR_ERR(fi_ecm);
324 		ecm_opts = container_of(fi_ecm, struct f_ecm_opts, func_inst);
325 		net = ecm_opts->net;
326 	} else {
327 		struct f_gether_opts *geth_opts;
328 
329 		fi_geth = usb_get_function_instance("geth");
330 		if (IS_ERR(fi_geth))
331 			return PTR_ERR(fi_geth);
332 		geth_opts = container_of(fi_geth, struct f_gether_opts,
333 					 func_inst);
334 		net = geth_opts->net;
335 	}
336 #endif
337 
338 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
339 	{
340 		fi_rndis = usb_get_function_instance("rndis");
341 		if (IS_ERR(fi_rndis)) {
342 			ret = PTR_ERR(fi_rndis);
343 			goto error;
344 		}
345 #ifndef CONFIG_USB_FUNCTIONFS_ETH
346 		net = container_of(fi_rndis, struct f_rndis_opts,
347 				   func_inst)->net;
348 #endif
349 	}
350 #endif
351 
352 #if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
353 	gether_set_qmult(net, qmult);
354 	if (!gether_set_host_addr(net, host_addr))
355 		pr_info("using host ethernet address: %s", host_addr);
356 	if (!gether_set_dev_addr(net, dev_addr))
357 		pr_info("using self ethernet address: %s", dev_addr);
358 #endif
359 
360 #if defined CONFIG_USB_FUNCTIONFS_RNDIS && defined CONFIG_USB_FUNCTIONFS_ETH
361 	gether_set_gadget(net, cdev->gadget);
362 	ret = gether_register_netdev(net);
363 	if (ret)
364 		goto error_rndis;
365 
366 	if (can_support_ecm(cdev->gadget)) {
367 		struct f_ecm_opts *ecm_opts;
368 
369 		ecm_opts = container_of(fi_ecm, struct f_ecm_opts, func_inst);
370 		ecm_opts->bound = true;
371 	} else {
372 		struct f_gether_opts *geth_opts;
373 
374 		geth_opts = container_of(fi_geth, struct f_gether_opts,
375 					 func_inst);
376 		geth_opts->bound = true;
377 	}
378 
379 	rndis_borrow_net(fi_rndis, net);
380 #endif
381 
382 	/* TODO: gstrings_attach? */
383 	ret = usb_string_ids_tab(cdev, gfs_strings);
384 	if (unlikely(ret < 0))
385 		goto error_rndis;
386 	gfs_dev_desc.iProduct = gfs_strings[USB_GADGET_PRODUCT_IDX].id;
387 
388 	if (gadget_is_otg(cdev->gadget) && !gfs_otg_desc[0]) {
389 		struct usb_descriptor_header *usb_desc;
390 
391 		usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
392 		if (!usb_desc) {
393 			ret = -ENOMEM;
394 			goto error_rndis;
395 		}
396 		usb_otg_descriptor_init(cdev->gadget, usb_desc);
397 		gfs_otg_desc[0] = usb_desc;
398 		gfs_otg_desc[1] = NULL;
399 	}
400 
401 	for (i = 0; i < ARRAY_SIZE(gfs_configurations); ++i) {
402 		struct gfs_configuration *c = gfs_configurations + i;
403 		int sid = USB_GADGET_FIRST_AVAIL_IDX + i;
404 
405 		c->c.label			= gfs_strings[sid].s;
406 		c->c.iConfiguration		= gfs_strings[sid].id;
407 		c->c.bConfigurationValue	= 1 + i;
408 		c->c.bmAttributes		= USB_CONFIG_ATT_SELFPOWER;
409 
410 		c->num = i;
411 
412 		ret = usb_add_config(cdev, &c->c, gfs_do_config);
413 		if (unlikely(ret < 0))
414 			goto error_unbind;
415 	}
416 	usb_composite_overwrite_options(cdev, &coverwrite);
417 	return 0;
418 
419 /* TODO */
420 error_unbind:
421 	kfree(gfs_otg_desc[0]);
422 	gfs_otg_desc[0] = NULL;
423 error_rndis:
424 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
425 	usb_put_function_instance(fi_rndis);
426 error:
427 #endif
428 #if defined CONFIG_USB_FUNCTIONFS_ETH
429 	if (can_support_ecm(cdev->gadget))
430 		usb_put_function_instance(fi_ecm);
431 	else
432 		usb_put_function_instance(fi_geth);
433 #endif
434 	return ret;
435 }
436 
437 /*
438  * It is assumed that gfs_unbind is called from a context where ffs_lock is held
439  */
440 static int gfs_unbind(struct usb_composite_dev *cdev)
441 {
442 	int i;
443 
444 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
445 	usb_put_function(f_rndis);
446 	usb_put_function_instance(fi_rndis);
447 #endif
448 
449 #if defined CONFIG_USB_FUNCTIONFS_ETH
450 	if (can_support_ecm(cdev->gadget)) {
451 		usb_put_function(f_ecm);
452 		usb_put_function_instance(fi_ecm);
453 	} else {
454 		usb_put_function(f_geth);
455 		usb_put_function_instance(fi_geth);
456 	}
457 #endif
458 	for (i = 0; i < N_CONF * func_num; ++i)
459 		usb_put_function(*(f_ffs[0] + i));
460 
461 	kfree(gfs_otg_desc[0]);
462 	gfs_otg_desc[0] = NULL;
463 
464 	return 0;
465 }
466 
467 /*
468  * It is assumed that gfs_do_config is called from a context where
469  * ffs_lock is held
470  */
471 static int gfs_do_config(struct usb_configuration *c)
472 {
473 	struct gfs_configuration *gc =
474 		container_of(c, struct gfs_configuration, c);
475 	int i;
476 	int ret;
477 
478 	if (missing_funcs)
479 		return -ENODEV;
480 
481 	if (gadget_is_otg(c->cdev->gadget)) {
482 		c->descriptors = gfs_otg_desc;
483 		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
484 	}
485 
486 	if (gc->eth) {
487 		ret = gc->eth(c);
488 		if (unlikely(ret < 0))
489 			return ret;
490 	}
491 
492 	for (i = 0; i < func_num; i++) {
493 		f_ffs[gc->num][i] = usb_get_function(fi_ffs[i]);
494 		if (IS_ERR(f_ffs[gc->num][i])) {
495 			ret = PTR_ERR(f_ffs[gc->num][i]);
496 			goto error;
497 		}
498 		ret = usb_add_function(c, f_ffs[gc->num][i]);
499 		if (ret < 0) {
500 			usb_put_function(f_ffs[gc->num][i]);
501 			goto error;
502 		}
503 	}
504 
505 	/*
506 	 * After previous do_configs there may be some invalid
507 	 * pointers in c->interface array.  This happens every time
508 	 * a user space function with fewer interfaces than a user
509 	 * space function that was run before the new one is run.  The
510 	 * compasit's set_config() assumes that if there is no more
511 	 * then MAX_CONFIG_INTERFACES interfaces in a configuration
512 	 * then there is a NULL pointer after the last interface in
513 	 * c->interface array.  We need to make sure this is true.
514 	 */
515 	if (c->next_interface_id < ARRAY_SIZE(c->interface))
516 		c->interface[c->next_interface_id] = NULL;
517 
518 	return 0;
519 error:
520 	while (--i >= 0) {
521 		if (!IS_ERR(f_ffs[gc->num][i]))
522 			usb_remove_function(c, f_ffs[gc->num][i]);
523 		usb_put_function(f_ffs[gc->num][i]);
524 	}
525 	return ret;
526 }
527 
528 #ifdef CONFIG_USB_FUNCTIONFS_ETH
529 
530 static int eth_bind_config(struct usb_configuration *c)
531 {
532 	int status = 0;
533 
534 	if (can_support_ecm(c->cdev->gadget)) {
535 		f_ecm = usb_get_function(fi_ecm);
536 		if (IS_ERR(f_ecm))
537 			return PTR_ERR(f_ecm);
538 
539 		status = usb_add_function(c, f_ecm);
540 		if (status < 0)
541 			usb_put_function(f_ecm);
542 
543 	} else {
544 		f_geth = usb_get_function(fi_geth);
545 		if (IS_ERR(f_geth))
546 			return PTR_ERR(f_geth);
547 
548 		status = usb_add_function(c, f_geth);
549 		if (status < 0)
550 			usb_put_function(f_geth);
551 	}
552 	return status;
553 }
554 
555 #endif
556 
557 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
558 
559 static int bind_rndis_config(struct usb_configuration *c)
560 {
561 	int status = 0;
562 
563 	f_rndis = usb_get_function(fi_rndis);
564 	if (IS_ERR(f_rndis))
565 		return PTR_ERR(f_rndis);
566 
567 	status = usb_add_function(c, f_rndis);
568 	if (status < 0)
569 		usb_put_function(f_rndis);
570 
571 	return status;
572 }
573 
574 #endif
575