1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * f_obex.c -- USB CDC OBEX function driver
4  *
5  * Copyright (C) 2008 Nokia Corporation
6  * Contact: Felipe Balbi <felipe.balbi@nokia.com>
7  *
8  * Based on f_acm.c by Al Borchers and David Brownell.
9  */
10 
11 /* #define VERBOSE_DEBUG */
12 
13 #include <linux/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/device.h>
16 #include <linux/module.h>
17 
18 #include "u_serial.h"
19 
20 
21 /*
22  * This CDC OBEX function support just packages a TTY-ish byte stream.
23  * A user mode server will put it into "raw" mode and handle all the
24  * relevant protocol details ... this is just a kernel passthrough.
25  * When possible, we prevent gadget enumeration until that server is
26  * ready to handle the commands.
27  */
28 
29 struct f_obex {
30 	struct gserial			port;
31 	u8				ctrl_id;
32 	u8				data_id;
33 	u8				cur_alt;
34 	u8				port_num;
35 };
36 
37 static inline struct f_obex *func_to_obex(struct usb_function *f)
38 {
39 	return container_of(f, struct f_obex, port.func);
40 }
41 
42 static inline struct f_obex *port_to_obex(struct gserial *p)
43 {
44 	return container_of(p, struct f_obex, port);
45 }
46 
47 /*-------------------------------------------------------------------------*/
48 
49 #define OBEX_CTRL_IDX	0
50 #define OBEX_DATA_IDX	1
51 
52 static struct usb_string obex_string_defs[] = {
53 	[OBEX_CTRL_IDX].s	= "CDC Object Exchange (OBEX)",
54 	[OBEX_DATA_IDX].s	= "CDC OBEX Data",
55 	{  },	/* end of list */
56 };
57 
58 static struct usb_gadget_strings obex_string_table = {
59 	.language		= 0x0409,	/* en-US */
60 	.strings		= obex_string_defs,
61 };
62 
63 static struct usb_gadget_strings *obex_strings[] = {
64 	&obex_string_table,
65 	NULL,
66 };
67 
68 /*-------------------------------------------------------------------------*/
69 
70 static struct usb_interface_descriptor obex_control_intf = {
71 	.bLength		= sizeof(obex_control_intf),
72 	.bDescriptorType	= USB_DT_INTERFACE,
73 	.bInterfaceNumber	= 0,
74 
75 	.bAlternateSetting	= 0,
76 	.bNumEndpoints		= 0,
77 	.bInterfaceClass	= USB_CLASS_COMM,
78 	.bInterfaceSubClass	= USB_CDC_SUBCLASS_OBEX,
79 };
80 
81 static struct usb_interface_descriptor obex_data_nop_intf = {
82 	.bLength		= sizeof(obex_data_nop_intf),
83 	.bDescriptorType	= USB_DT_INTERFACE,
84 	.bInterfaceNumber	= 1,
85 
86 	.bAlternateSetting	= 0,
87 	.bNumEndpoints		= 0,
88 	.bInterfaceClass	= USB_CLASS_CDC_DATA,
89 };
90 
91 static struct usb_interface_descriptor obex_data_intf = {
92 	.bLength		= sizeof(obex_data_intf),
93 	.bDescriptorType	= USB_DT_INTERFACE,
94 	.bInterfaceNumber	= 2,
95 
96 	.bAlternateSetting	= 1,
97 	.bNumEndpoints		= 2,
98 	.bInterfaceClass	= USB_CLASS_CDC_DATA,
99 };
100 
101 static struct usb_cdc_header_desc obex_cdc_header_desc = {
102 	.bLength		= sizeof(obex_cdc_header_desc),
103 	.bDescriptorType	= USB_DT_CS_INTERFACE,
104 	.bDescriptorSubType	= USB_CDC_HEADER_TYPE,
105 	.bcdCDC			= cpu_to_le16(0x0120),
106 };
107 
108 static struct usb_cdc_union_desc obex_cdc_union_desc = {
109 	.bLength		= sizeof(obex_cdc_union_desc),
110 	.bDescriptorType	= USB_DT_CS_INTERFACE,
111 	.bDescriptorSubType	= USB_CDC_UNION_TYPE,
112 	.bMasterInterface0	= 1,
113 	.bSlaveInterface0	= 2,
114 };
115 
116 static struct usb_cdc_obex_desc obex_desc = {
117 	.bLength		= sizeof(obex_desc),
118 	.bDescriptorType	= USB_DT_CS_INTERFACE,
119 	.bDescriptorSubType	= USB_CDC_OBEX_TYPE,
120 	.bcdVersion		= cpu_to_le16(0x0100),
121 };
122 
123 /* High-Speed Support */
124 
125 static struct usb_endpoint_descriptor obex_hs_ep_out_desc = {
126 	.bLength		= USB_DT_ENDPOINT_SIZE,
127 	.bDescriptorType	= USB_DT_ENDPOINT,
128 
129 	.bEndpointAddress	= USB_DIR_OUT,
130 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
131 	.wMaxPacketSize		= cpu_to_le16(512),
132 };
133 
134 static struct usb_endpoint_descriptor obex_hs_ep_in_desc = {
135 	.bLength		= USB_DT_ENDPOINT_SIZE,
136 	.bDescriptorType	= USB_DT_ENDPOINT,
137 
138 	.bEndpointAddress	= USB_DIR_IN,
139 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
140 	.wMaxPacketSize		= cpu_to_le16(512),
141 };
142 
143 static struct usb_descriptor_header *hs_function[] = {
144 	(struct usb_descriptor_header *) &obex_control_intf,
145 	(struct usb_descriptor_header *) &obex_cdc_header_desc,
146 	(struct usb_descriptor_header *) &obex_desc,
147 	(struct usb_descriptor_header *) &obex_cdc_union_desc,
148 
149 	(struct usb_descriptor_header *) &obex_data_nop_intf,
150 	(struct usb_descriptor_header *) &obex_data_intf,
151 	(struct usb_descriptor_header *) &obex_hs_ep_in_desc,
152 	(struct usb_descriptor_header *) &obex_hs_ep_out_desc,
153 	NULL,
154 };
155 
156 /* Full-Speed Support */
157 
158 static struct usb_endpoint_descriptor obex_fs_ep_in_desc = {
159 	.bLength		= USB_DT_ENDPOINT_SIZE,
160 	.bDescriptorType	= USB_DT_ENDPOINT,
161 
162 	.bEndpointAddress	= USB_DIR_IN,
163 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
164 };
165 
166 static struct usb_endpoint_descriptor obex_fs_ep_out_desc = {
167 	.bLength		= USB_DT_ENDPOINT_SIZE,
168 	.bDescriptorType	= USB_DT_ENDPOINT,
169 
170 	.bEndpointAddress	= USB_DIR_OUT,
171 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
172 };
173 
174 static struct usb_descriptor_header *fs_function[] = {
175 	(struct usb_descriptor_header *) &obex_control_intf,
176 	(struct usb_descriptor_header *) &obex_cdc_header_desc,
177 	(struct usb_descriptor_header *) &obex_desc,
178 	(struct usb_descriptor_header *) &obex_cdc_union_desc,
179 
180 	(struct usb_descriptor_header *) &obex_data_nop_intf,
181 	(struct usb_descriptor_header *) &obex_data_intf,
182 	(struct usb_descriptor_header *) &obex_fs_ep_in_desc,
183 	(struct usb_descriptor_header *) &obex_fs_ep_out_desc,
184 	NULL,
185 };
186 
187 /*-------------------------------------------------------------------------*/
188 
189 static int obex_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
190 {
191 	struct f_obex		*obex = func_to_obex(f);
192 	struct usb_composite_dev *cdev = f->config->cdev;
193 
194 	if (intf == obex->ctrl_id) {
195 		if (alt != 0)
196 			goto fail;
197 		/* NOP */
198 		dev_dbg(&cdev->gadget->dev,
199 			"reset obex ttyGS%d control\n", obex->port_num);
200 
201 	} else if (intf == obex->data_id) {
202 		if (alt > 1)
203 			goto fail;
204 
205 		if (obex->port.in->enabled) {
206 			dev_dbg(&cdev->gadget->dev,
207 				"reset obex ttyGS%d\n", obex->port_num);
208 			gserial_disconnect(&obex->port);
209 		}
210 
211 		if (!obex->port.in->desc || !obex->port.out->desc) {
212 			dev_dbg(&cdev->gadget->dev,
213 				"init obex ttyGS%d\n", obex->port_num);
214 			if (config_ep_by_speed(cdev->gadget, f,
215 					       obex->port.in) ||
216 			    config_ep_by_speed(cdev->gadget, f,
217 					       obex->port.out)) {
218 				obex->port.out->desc = NULL;
219 				obex->port.in->desc = NULL;
220 				goto fail;
221 			}
222 		}
223 
224 		if (alt == 1) {
225 			dev_dbg(&cdev->gadget->dev,
226 				"activate obex ttyGS%d\n", obex->port_num);
227 			gserial_connect(&obex->port, obex->port_num);
228 		}
229 
230 	} else
231 		goto fail;
232 
233 	obex->cur_alt = alt;
234 
235 	return 0;
236 
237 fail:
238 	return -EINVAL;
239 }
240 
241 static int obex_get_alt(struct usb_function *f, unsigned intf)
242 {
243 	struct f_obex		*obex = func_to_obex(f);
244 
245 	return obex->cur_alt;
246 }
247 
248 static void obex_disable(struct usb_function *f)
249 {
250 	struct f_obex	*obex = func_to_obex(f);
251 	struct usb_composite_dev *cdev = f->config->cdev;
252 
253 	dev_dbg(&cdev->gadget->dev, "obex ttyGS%d disable\n", obex->port_num);
254 	gserial_disconnect(&obex->port);
255 }
256 
257 /*-------------------------------------------------------------------------*/
258 
259 static void obex_connect(struct gserial *g)
260 {
261 	struct f_obex		*obex = port_to_obex(g);
262 	struct usb_composite_dev *cdev = g->func.config->cdev;
263 	int			status;
264 
265 	status = usb_function_activate(&g->func);
266 	if (status)
267 		dev_dbg(&cdev->gadget->dev,
268 			"obex ttyGS%d function activate --> %d\n",
269 			obex->port_num, status);
270 }
271 
272 static void obex_disconnect(struct gserial *g)
273 {
274 	struct f_obex		*obex = port_to_obex(g);
275 	struct usb_composite_dev *cdev = g->func.config->cdev;
276 	int			status;
277 
278 	status = usb_function_deactivate(&g->func);
279 	if (status)
280 		dev_dbg(&cdev->gadget->dev,
281 			"obex ttyGS%d function deactivate --> %d\n",
282 			obex->port_num, status);
283 }
284 
285 /*-------------------------------------------------------------------------*/
286 
287 /* Some controllers can't support CDC OBEX ... */
288 static inline bool can_support_obex(struct usb_configuration *c)
289 {
290 	/* Since the first interface is a NOP, we can ignore the
291 	 * issue of multi-interface support on most controllers.
292 	 *
293 	 * Altsettings are mandatory, however...
294 	 */
295 	if (!gadget_is_altset_supported(c->cdev->gadget))
296 		return false;
297 
298 	/* everything else is *probably* fine ... */
299 	return true;
300 }
301 
302 static int obex_bind(struct usb_configuration *c, struct usb_function *f)
303 {
304 	struct usb_composite_dev *cdev = c->cdev;
305 	struct f_obex		*obex = func_to_obex(f);
306 	struct usb_string	*us;
307 	int			status;
308 	struct usb_ep		*ep;
309 
310 	if (!can_support_obex(c))
311 		return -EINVAL;
312 
313 	us = usb_gstrings_attach(cdev, obex_strings,
314 				 ARRAY_SIZE(obex_string_defs));
315 	if (IS_ERR(us))
316 		return PTR_ERR(us);
317 	obex_control_intf.iInterface = us[OBEX_CTRL_IDX].id;
318 	obex_data_nop_intf.iInterface = us[OBEX_DATA_IDX].id;
319 	obex_data_intf.iInterface = us[OBEX_DATA_IDX].id;
320 
321 	/* allocate instance-specific interface IDs, and patch descriptors */
322 
323 	status = usb_interface_id(c, f);
324 	if (status < 0)
325 		goto fail;
326 	obex->ctrl_id = status;
327 
328 	obex_control_intf.bInterfaceNumber = status;
329 	obex_cdc_union_desc.bMasterInterface0 = status;
330 
331 	status = usb_interface_id(c, f);
332 	if (status < 0)
333 		goto fail;
334 	obex->data_id = status;
335 
336 	obex_data_nop_intf.bInterfaceNumber = status;
337 	obex_data_intf.bInterfaceNumber = status;
338 	obex_cdc_union_desc.bSlaveInterface0 = status;
339 
340 	/* allocate instance-specific endpoints */
341 
342 	status = -ENODEV;
343 	ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_in_desc);
344 	if (!ep)
345 		goto fail;
346 	obex->port.in = ep;
347 
348 	ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_out_desc);
349 	if (!ep)
350 		goto fail;
351 	obex->port.out = ep;
352 
353 	/* support all relevant hardware speeds... we expect that when
354 	 * hardware is dual speed, all bulk-capable endpoints work at
355 	 * both speeds
356 	 */
357 
358 	obex_hs_ep_in_desc.bEndpointAddress =
359 		obex_fs_ep_in_desc.bEndpointAddress;
360 	obex_hs_ep_out_desc.bEndpointAddress =
361 		obex_fs_ep_out_desc.bEndpointAddress;
362 
363 	status = usb_assign_descriptors(f, fs_function, hs_function, NULL,
364 					NULL);
365 	if (status)
366 		goto fail;
367 
368 	dev_dbg(&cdev->gadget->dev, "obex ttyGS%d: IN/%s OUT/%s\n",
369 		obex->port_num,
370 		obex->port.in->name, obex->port.out->name);
371 
372 	return 0;
373 
374 fail:
375 	ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
376 
377 	return status;
378 }
379 
380 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
381 {
382 	return container_of(to_config_group(item), struct f_serial_opts,
383 			    func_inst.group);
384 }
385 
386 static void obex_attr_release(struct config_item *item)
387 {
388 	struct f_serial_opts *opts = to_f_serial_opts(item);
389 
390 	usb_put_function_instance(&opts->func_inst);
391 }
392 
393 static struct configfs_item_operations obex_item_ops = {
394 	.release	= obex_attr_release,
395 };
396 
397 static ssize_t f_obex_port_num_show(struct config_item *item, char *page)
398 {
399 	return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
400 }
401 
402 CONFIGFS_ATTR_RO(f_obex_, port_num);
403 
404 static struct configfs_attribute *acm_attrs[] = {
405 	&f_obex_attr_port_num,
406 	NULL,
407 };
408 
409 static const struct config_item_type obex_func_type = {
410 	.ct_item_ops	= &obex_item_ops,
411 	.ct_attrs	= acm_attrs,
412 	.ct_owner	= THIS_MODULE,
413 };
414 
415 static void obex_free_inst(struct usb_function_instance *f)
416 {
417 	struct f_serial_opts *opts;
418 
419 	opts = container_of(f, struct f_serial_opts, func_inst);
420 	gserial_free_line(opts->port_num);
421 	kfree(opts);
422 }
423 
424 static struct usb_function_instance *obex_alloc_inst(void)
425 {
426 	struct f_serial_opts *opts;
427 	int ret;
428 
429 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
430 	if (!opts)
431 		return ERR_PTR(-ENOMEM);
432 
433 	opts->func_inst.free_func_inst = obex_free_inst;
434 	ret = gserial_alloc_line_no_console(&opts->port_num);
435 	if (ret) {
436 		kfree(opts);
437 		return ERR_PTR(ret);
438 	}
439 	config_group_init_type_name(&opts->func_inst.group, "",
440 				    &obex_func_type);
441 
442 	return &opts->func_inst;
443 }
444 
445 static void obex_free(struct usb_function *f)
446 {
447 	struct f_obex *obex;
448 
449 	obex = func_to_obex(f);
450 	kfree(obex);
451 }
452 
453 static void obex_unbind(struct usb_configuration *c, struct usb_function *f)
454 {
455 	usb_free_all_descriptors(f);
456 }
457 
458 static struct usb_function *obex_alloc(struct usb_function_instance *fi)
459 {
460 	struct f_obex	*obex;
461 	struct f_serial_opts *opts;
462 
463 	/* allocate and initialize one new instance */
464 	obex = kzalloc(sizeof(*obex), GFP_KERNEL);
465 	if (!obex)
466 		return ERR_PTR(-ENOMEM);
467 
468 	opts = container_of(fi, struct f_serial_opts, func_inst);
469 
470 	obex->port_num = opts->port_num;
471 
472 	obex->port.connect = obex_connect;
473 	obex->port.disconnect = obex_disconnect;
474 
475 	obex->port.func.name = "obex";
476 	/* descriptors are per-instance copies */
477 	obex->port.func.bind = obex_bind;
478 	obex->port.func.unbind = obex_unbind;
479 	obex->port.func.set_alt = obex_set_alt;
480 	obex->port.func.get_alt = obex_get_alt;
481 	obex->port.func.disable = obex_disable;
482 	obex->port.func.free_func = obex_free;
483 	obex->port.func.bind_deactivated = true;
484 
485 	return &obex->port.func;
486 }
487 
488 DECLARE_USB_FUNCTION_INIT(obex, obex_alloc_inst, obex_alloc);
489 MODULE_AUTHOR("Felipe Balbi");
490 MODULE_LICENSE("GPL");
491