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