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