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  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
 29struct f_obex {
 30	struct gserial			port;
 31	u8				ctrl_id;
 32	u8				data_id;
 33	u8				cur_alt;
 34	u8				port_num;
 35};
 36
 37static inline struct f_obex *func_to_obex(struct usb_function *f)
 38{
 39	return container_of(f, struct f_obex, port.func);
 40}
 41
 42static 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
 52static 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
 58static struct usb_gadget_strings obex_string_table = {
 59	.language		= 0x0409,	/* en-US */
 60	.strings		= obex_string_defs,
 61};
 62
 63static struct usb_gadget_strings *obex_strings[] = {
 64	&obex_string_table,
 65	NULL,
 66};
 67
 68/*-------------------------------------------------------------------------*/
 69
 70static 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
 81static 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
 91static 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
101static 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
108static 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
116static 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
125static 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
134static 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
143static 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
158static 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
166static 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
174static 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
189static 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
237fail:
238	return -EINVAL;
239}
240
241static 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
248static 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
259static 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
272static 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 ... */
288static 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
302static 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
374fail:
375	ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
376
377	return status;
378}
379
380static 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
386static 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
393static struct configfs_item_operations obex_item_ops = {
394	.release	= obex_attr_release,
395};
396
397static 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
402CONFIGFS_ATTR_RO(f_obex_, port_num);
403
404static struct configfs_attribute *acm_attrs[] = {
405	&f_obex_attr_port_num,
406	NULL,
407};
408
409static 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
415static 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
424static 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
445static 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
453static void obex_unbind(struct usb_configuration *c, struct usb_function *f)
454{
455	usb_free_all_descriptors(f);
456}
457
458static 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
488DECLARE_USB_FUNCTION_INIT(obex, obex_alloc_inst, obex_alloc);
489MODULE_AUTHOR("Felipe Balbi");
490MODULE_LICENSE("GPL");