1 /*
2  * f_obex.c -- USB CDC OBEX function driver
3  *
4  * Copyright (C) 2008 Nokia Corporation
5  * Contact: Felipe Balbi <felipe.balbi@nokia.com>
6  *
7  * Based on f_acm.c by Al Borchers and David Brownell.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  */
14 
15 /* #define VERBOSE_DEBUG */
16 
17 #include <linux/slab.h>
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/module.h>
21 
22 #include "u_serial.h"
23 #include "gadget_chips.h"
24 
25 
26 /*
27  * This CDC OBEX function support just packages a TTY-ish byte stream.
28  * A user mode server will put it into "raw" mode and handle all the
29  * relevant protocol details ... this is just a kernel passthrough.
30  * When possible, we prevent gadget enumeration until that server is
31  * ready to handle the commands.
32  */
33 
34 struct f_obex {
35 	struct gserial			port;
36 	u8				ctrl_id;
37 	u8				data_id;
38 	u8				cur_alt;
39 	u8				port_num;
40 	u8				can_activate;
41 };
42 
43 static inline struct f_obex *func_to_obex(struct usb_function *f)
44 {
45 	return container_of(f, struct f_obex, port.func);
46 }
47 
48 static inline struct f_obex *port_to_obex(struct gserial *p)
49 {
50 	return container_of(p, struct f_obex, port);
51 }
52 
53 /*-------------------------------------------------------------------------*/
54 
55 #define OBEX_CTRL_IDX	0
56 #define OBEX_DATA_IDX	1
57 
58 static struct usb_string obex_string_defs[] = {
59 	[OBEX_CTRL_IDX].s	= "CDC Object Exchange (OBEX)",
60 	[OBEX_DATA_IDX].s	= "CDC OBEX Data",
61 	{  },	/* end of list */
62 };
63 
64 static struct usb_gadget_strings obex_string_table = {
65 	.language		= 0x0409,	/* en-US */
66 	.strings		= obex_string_defs,
67 };
68 
69 static struct usb_gadget_strings *obex_strings[] = {
70 	&obex_string_table,
71 	NULL,
72 };
73 
74 /*-------------------------------------------------------------------------*/
75 
76 static struct usb_interface_descriptor obex_control_intf = {
77 	.bLength		= sizeof(obex_control_intf),
78 	.bDescriptorType	= USB_DT_INTERFACE,
79 	.bInterfaceNumber	= 0,
80 
81 	.bAlternateSetting	= 0,
82 	.bNumEndpoints		= 0,
83 	.bInterfaceClass	= USB_CLASS_COMM,
84 	.bInterfaceSubClass	= USB_CDC_SUBCLASS_OBEX,
85 };
86 
87 static struct usb_interface_descriptor obex_data_nop_intf = {
88 	.bLength		= sizeof(obex_data_nop_intf),
89 	.bDescriptorType	= USB_DT_INTERFACE,
90 	.bInterfaceNumber	= 1,
91 
92 	.bAlternateSetting	= 0,
93 	.bNumEndpoints		= 0,
94 	.bInterfaceClass	= USB_CLASS_CDC_DATA,
95 };
96 
97 static struct usb_interface_descriptor obex_data_intf = {
98 	.bLength		= sizeof(obex_data_intf),
99 	.bDescriptorType	= USB_DT_INTERFACE,
100 	.bInterfaceNumber	= 2,
101 
102 	.bAlternateSetting	= 1,
103 	.bNumEndpoints		= 2,
104 	.bInterfaceClass	= USB_CLASS_CDC_DATA,
105 };
106 
107 static struct usb_cdc_header_desc obex_cdc_header_desc = {
108 	.bLength		= sizeof(obex_cdc_header_desc),
109 	.bDescriptorType	= USB_DT_CS_INTERFACE,
110 	.bDescriptorSubType	= USB_CDC_HEADER_TYPE,
111 	.bcdCDC			= cpu_to_le16(0x0120),
112 };
113 
114 static struct usb_cdc_union_desc obex_cdc_union_desc = {
115 	.bLength		= sizeof(obex_cdc_union_desc),
116 	.bDescriptorType	= USB_DT_CS_INTERFACE,
117 	.bDescriptorSubType	= USB_CDC_UNION_TYPE,
118 	.bMasterInterface0	= 1,
119 	.bSlaveInterface0	= 2,
120 };
121 
122 static struct usb_cdc_obex_desc obex_desc = {
123 	.bLength		= sizeof(obex_desc),
124 	.bDescriptorType	= USB_DT_CS_INTERFACE,
125 	.bDescriptorSubType	= USB_CDC_OBEX_TYPE,
126 	.bcdVersion		= cpu_to_le16(0x0100),
127 };
128 
129 /* High-Speed Support */
130 
131 static struct usb_endpoint_descriptor obex_hs_ep_out_desc = {
132 	.bLength		= USB_DT_ENDPOINT_SIZE,
133 	.bDescriptorType	= USB_DT_ENDPOINT,
134 
135 	.bEndpointAddress	= USB_DIR_OUT,
136 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
137 	.wMaxPacketSize		= cpu_to_le16(512),
138 };
139 
140 static struct usb_endpoint_descriptor obex_hs_ep_in_desc = {
141 	.bLength		= USB_DT_ENDPOINT_SIZE,
142 	.bDescriptorType	= USB_DT_ENDPOINT,
143 
144 	.bEndpointAddress	= USB_DIR_IN,
145 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
146 	.wMaxPacketSize		= cpu_to_le16(512),
147 };
148 
149 static struct usb_descriptor_header *hs_function[] = {
150 	(struct usb_descriptor_header *) &obex_control_intf,
151 	(struct usb_descriptor_header *) &obex_cdc_header_desc,
152 	(struct usb_descriptor_header *) &obex_desc,
153 	(struct usb_descriptor_header *) &obex_cdc_union_desc,
154 
155 	(struct usb_descriptor_header *) &obex_data_nop_intf,
156 	(struct usb_descriptor_header *) &obex_data_intf,
157 	(struct usb_descriptor_header *) &obex_hs_ep_in_desc,
158 	(struct usb_descriptor_header *) &obex_hs_ep_out_desc,
159 	NULL,
160 };
161 
162 /* Full-Speed Support */
163 
164 static struct usb_endpoint_descriptor obex_fs_ep_in_desc = {
165 	.bLength		= USB_DT_ENDPOINT_SIZE,
166 	.bDescriptorType	= USB_DT_ENDPOINT,
167 
168 	.bEndpointAddress	= USB_DIR_IN,
169 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
170 };
171 
172 static struct usb_endpoint_descriptor obex_fs_ep_out_desc = {
173 	.bLength		= USB_DT_ENDPOINT_SIZE,
174 	.bDescriptorType	= USB_DT_ENDPOINT,
175 
176 	.bEndpointAddress	= USB_DIR_OUT,
177 	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
178 };
179 
180 static struct usb_descriptor_header *fs_function[] = {
181 	(struct usb_descriptor_header *) &obex_control_intf,
182 	(struct usb_descriptor_header *) &obex_cdc_header_desc,
183 	(struct usb_descriptor_header *) &obex_desc,
184 	(struct usb_descriptor_header *) &obex_cdc_union_desc,
185 
186 	(struct usb_descriptor_header *) &obex_data_nop_intf,
187 	(struct usb_descriptor_header *) &obex_data_intf,
188 	(struct usb_descriptor_header *) &obex_fs_ep_in_desc,
189 	(struct usb_descriptor_header *) &obex_fs_ep_out_desc,
190 	NULL,
191 };
192 
193 /*-------------------------------------------------------------------------*/
194 
195 static int obex_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
196 {
197 	struct f_obex		*obex = func_to_obex(f);
198 	struct usb_composite_dev *cdev = f->config->cdev;
199 
200 	if (intf == obex->ctrl_id) {
201 		if (alt != 0)
202 			goto fail;
203 		/* NOP */
204 		dev_dbg(&cdev->gadget->dev,
205 			"reset obex ttyGS%d control\n", obex->port_num);
206 
207 	} else if (intf == obex->data_id) {
208 		if (alt > 1)
209 			goto fail;
210 
211 		if (obex->port.in->driver_data) {
212 			dev_dbg(&cdev->gadget->dev,
213 				"reset obex ttyGS%d\n", obex->port_num);
214 			gserial_disconnect(&obex->port);
215 		}
216 
217 		if (!obex->port.in->desc || !obex->port.out->desc) {
218 			dev_dbg(&cdev->gadget->dev,
219 				"init obex ttyGS%d\n", obex->port_num);
220 			if (config_ep_by_speed(cdev->gadget, f,
221 					       obex->port.in) ||
222 			    config_ep_by_speed(cdev->gadget, f,
223 					       obex->port.out)) {
224 				obex->port.out->desc = NULL;
225 				obex->port.in->desc = NULL;
226 				goto fail;
227 			}
228 		}
229 
230 		if (alt == 1) {
231 			dev_dbg(&cdev->gadget->dev,
232 				"activate obex ttyGS%d\n", obex->port_num);
233 			gserial_connect(&obex->port, obex->port_num);
234 		}
235 
236 	} else
237 		goto fail;
238 
239 	obex->cur_alt = alt;
240 
241 	return 0;
242 
243 fail:
244 	return -EINVAL;
245 }
246 
247 static int obex_get_alt(struct usb_function *f, unsigned intf)
248 {
249 	struct f_obex		*obex = func_to_obex(f);
250 
251 	return obex->cur_alt;
252 }
253 
254 static void obex_disable(struct usb_function *f)
255 {
256 	struct f_obex	*obex = func_to_obex(f);
257 	struct usb_composite_dev *cdev = f->config->cdev;
258 
259 	dev_dbg(&cdev->gadget->dev, "obex ttyGS%d disable\n", obex->port_num);
260 	gserial_disconnect(&obex->port);
261 }
262 
263 /*-------------------------------------------------------------------------*/
264 
265 static void obex_connect(struct gserial *g)
266 {
267 	struct f_obex		*obex = port_to_obex(g);
268 	struct usb_composite_dev *cdev = g->func.config->cdev;
269 	int			status;
270 
271 	if (!obex->can_activate)
272 		return;
273 
274 	status = usb_function_activate(&g->func);
275 	if (status)
276 		dev_dbg(&cdev->gadget->dev,
277 			"obex ttyGS%d function activate --> %d\n",
278 			obex->port_num, status);
279 }
280 
281 static void obex_disconnect(struct gserial *g)
282 {
283 	struct f_obex		*obex = port_to_obex(g);
284 	struct usb_composite_dev *cdev = g->func.config->cdev;
285 	int			status;
286 
287 	if (!obex->can_activate)
288 		return;
289 
290 	status = usb_function_deactivate(&g->func);
291 	if (status)
292 		dev_dbg(&cdev->gadget->dev,
293 			"obex ttyGS%d function deactivate --> %d\n",
294 			obex->port_num, status);
295 }
296 
297 /*-------------------------------------------------------------------------*/
298 
299 /* Some controllers can't support CDC OBEX ... */
300 static inline bool can_support_obex(struct usb_configuration *c)
301 {
302 	/* Since the first interface is a NOP, we can ignore the
303 	 * issue of multi-interface support on most controllers.
304 	 *
305 	 * Altsettings are mandatory, however...
306 	 */
307 	if (!gadget_supports_altsettings(c->cdev->gadget))
308 		return false;
309 
310 	/* everything else is *probably* fine ... */
311 	return true;
312 }
313 
314 static int obex_bind(struct usb_configuration *c, struct usb_function *f)
315 {
316 	struct usb_composite_dev *cdev = c->cdev;
317 	struct f_obex		*obex = func_to_obex(f);
318 	struct usb_string	*us;
319 	int			status;
320 	struct usb_ep		*ep;
321 
322 	if (!can_support_obex(c))
323 		return -EINVAL;
324 
325 	us = usb_gstrings_attach(cdev, obex_strings,
326 				 ARRAY_SIZE(obex_string_defs));
327 	if (IS_ERR(us))
328 		return PTR_ERR(us);
329 	obex_control_intf.iInterface = us[OBEX_CTRL_IDX].id;
330 	obex_data_nop_intf.iInterface = us[OBEX_DATA_IDX].id;
331 	obex_data_intf.iInterface = us[OBEX_DATA_IDX].id;
332 
333 	/* allocate instance-specific interface IDs, and patch descriptors */
334 
335 	status = usb_interface_id(c, f);
336 	if (status < 0)
337 		goto fail;
338 	obex->ctrl_id = status;
339 
340 	obex_control_intf.bInterfaceNumber = status;
341 	obex_cdc_union_desc.bMasterInterface0 = status;
342 
343 	status = usb_interface_id(c, f);
344 	if (status < 0)
345 		goto fail;
346 	obex->data_id = status;
347 
348 	obex_data_nop_intf.bInterfaceNumber = status;
349 	obex_data_intf.bInterfaceNumber = status;
350 	obex_cdc_union_desc.bSlaveInterface0 = status;
351 
352 	/* allocate instance-specific endpoints */
353 
354 	status = -ENODEV;
355 	ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_in_desc);
356 	if (!ep)
357 		goto fail;
358 	obex->port.in = ep;
359 	ep->driver_data = cdev;	/* claim */
360 
361 	ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_out_desc);
362 	if (!ep)
363 		goto fail;
364 	obex->port.out = ep;
365 	ep->driver_data = cdev;	/* claim */
366 
367 	/* support all relevant hardware speeds... we expect that when
368 	 * hardware is dual speed, all bulk-capable endpoints work at
369 	 * both speeds
370 	 */
371 
372 	obex_hs_ep_in_desc.bEndpointAddress =
373 		obex_fs_ep_in_desc.bEndpointAddress;
374 	obex_hs_ep_out_desc.bEndpointAddress =
375 		obex_fs_ep_out_desc.bEndpointAddress;
376 
377 	status = usb_assign_descriptors(f, fs_function, hs_function, NULL);
378 	if (status)
379 		goto fail;
380 
381 	/* Avoid letting this gadget enumerate until the userspace
382 	 * OBEX server is active.
383 	 */
384 	status = usb_function_deactivate(f);
385 	if (status < 0)
386 		WARNING(cdev, "obex ttyGS%d: can't prevent enumeration, %d\n",
387 			obex->port_num, status);
388 	else
389 		obex->can_activate = true;
390 
391 
392 	dev_dbg(&cdev->gadget->dev, "obex ttyGS%d: %s speed IN/%s OUT/%s\n",
393 		obex->port_num,
394 		gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
395 		obex->port.in->name, obex->port.out->name);
396 
397 	return 0;
398 
399 fail:
400 	/* we might as well release our claims on endpoints */
401 	if (obex->port.out)
402 		obex->port.out->driver_data = NULL;
403 	if (obex->port.in)
404 		obex->port.in->driver_data = NULL;
405 
406 	ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
407 
408 	return status;
409 }
410 
411 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
412 {
413 	return container_of(to_config_group(item), struct f_serial_opts,
414 			    func_inst.group);
415 }
416 
417 CONFIGFS_ATTR_STRUCT(f_serial_opts);
418 static ssize_t f_obex_attr_show(struct config_item *item,
419 				struct configfs_attribute *attr,
420 				char *page)
421 {
422 	struct f_serial_opts *opts = to_f_serial_opts(item);
423 	struct f_serial_opts_attribute *f_serial_opts_attr =
424 		container_of(attr, struct f_serial_opts_attribute, attr);
425 	ssize_t ret = 0;
426 
427 	if (f_serial_opts_attr->show)
428 		ret = f_serial_opts_attr->show(opts, page);
429 
430 	return ret;
431 }
432 
433 static void obex_attr_release(struct config_item *item)
434 {
435 	struct f_serial_opts *opts = to_f_serial_opts(item);
436 
437 	usb_put_function_instance(&opts->func_inst);
438 }
439 
440 static struct configfs_item_operations obex_item_ops = {
441 	.release	= obex_attr_release,
442 	.show_attribute = f_obex_attr_show,
443 };
444 
445 static ssize_t f_obex_port_num_show(struct f_serial_opts *opts, char *page)
446 {
447 	return sprintf(page, "%u\n", opts->port_num);
448 }
449 
450 static struct f_serial_opts_attribute f_obex_port_num =
451 	__CONFIGFS_ATTR_RO(port_num, f_obex_port_num_show);
452 
453 static struct configfs_attribute *acm_attrs[] = {
454 	&f_obex_port_num.attr,
455 	NULL,
456 };
457 
458 static struct config_item_type obex_func_type = {
459 	.ct_item_ops	= &obex_item_ops,
460 	.ct_attrs	= acm_attrs,
461 	.ct_owner	= THIS_MODULE,
462 };
463 
464 static void obex_free_inst(struct usb_function_instance *f)
465 {
466 	struct f_serial_opts *opts;
467 
468 	opts = container_of(f, struct f_serial_opts, func_inst);
469 	gserial_free_line(opts->port_num);
470 	kfree(opts);
471 }
472 
473 static struct usb_function_instance *obex_alloc_inst(void)
474 {
475 	struct f_serial_opts *opts;
476 	int ret;
477 
478 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
479 	if (!opts)
480 		return ERR_PTR(-ENOMEM);
481 
482 	opts->func_inst.free_func_inst = obex_free_inst;
483 	ret = gserial_alloc_line(&opts->port_num);
484 	if (ret) {
485 		kfree(opts);
486 		return ERR_PTR(ret);
487 	}
488 	config_group_init_type_name(&opts->func_inst.group, "",
489 				    &obex_func_type);
490 
491 	return &opts->func_inst;
492 }
493 
494 static void obex_free(struct usb_function *f)
495 {
496 	struct f_obex *obex;
497 
498 	obex = func_to_obex(f);
499 	kfree(obex);
500 }
501 
502 static void obex_unbind(struct usb_configuration *c, struct usb_function *f)
503 {
504 	usb_free_all_descriptors(f);
505 }
506 
507 static struct usb_function *obex_alloc(struct usb_function_instance *fi)
508 {
509 	struct f_obex	*obex;
510 	struct f_serial_opts *opts;
511 
512 	/* allocate and initialize one new instance */
513 	obex = kzalloc(sizeof(*obex), GFP_KERNEL);
514 	if (!obex)
515 		return ERR_PTR(-ENOMEM);
516 
517 	opts = container_of(fi, struct f_serial_opts, func_inst);
518 
519 	obex->port_num = opts->port_num;
520 
521 	obex->port.connect = obex_connect;
522 	obex->port.disconnect = obex_disconnect;
523 
524 	obex->port.func.name = "obex";
525 	/* descriptors are per-instance copies */
526 	obex->port.func.bind = obex_bind;
527 	obex->port.func.unbind = obex_unbind;
528 	obex->port.func.set_alt = obex_set_alt;
529 	obex->port.func.get_alt = obex_get_alt;
530 	obex->port.func.disable = obex_disable;
531 	obex->port.func.free_func = obex_free;
532 
533 	return &obex->port.func;
534 }
535 
536 DECLARE_USB_FUNCTION_INIT(obex, obex_alloc_inst, obex_alloc);
537 MODULE_AUTHOR("Felipe Balbi");
538 MODULE_LICENSE("GPL");
539