summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/function/f_serial.c
blob: 1d162e200e831ce1320a8e3d3f36f3bbd82b5a92 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
/*
 * f_serial.c - generic USB serial function driver
 *
 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
 * Copyright (C) 2008 by David Brownell
 * Copyright (C) 2008 by Nokia Corporation
 *
 * This software is distributed under the terms of the GNU General
 * Public License ("GPL") as published by the Free Software Foundation,
 * either version 2 of that License or (at your option) any later version.
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>

#include "u_serial.h"


/*
 * This function packages a simple "generic serial" port with no real
 * control mechanisms, just raw data transfer over two bulk endpoints.
 *
 * Because it's not standardized, this isn't as interoperable as the
 * CDC ACM driver.  However, for many purposes it's just as functional
 * if you can arrange appropriate host side drivers.
 */

struct f_gser {
	struct gserial			port;
	u8				data_id;
	u8				port_num;
};

static inline struct f_gser *func_to_gser(struct usb_function *f)
{
	return container_of(f, struct f_gser, port.func);
}

/*-------------------------------------------------------------------------*/

/* interface descriptor: */

static struct usb_interface_descriptor gser_interface_desc = {
	.bLength =		USB_DT_INTERFACE_SIZE,
	.bDescriptorType =	USB_DT_INTERFACE,
	/* .bInterfaceNumber = DYNAMIC */
	.bNumEndpoints =	2,
	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
	.bInterfaceSubClass =	0,
	.bInterfaceProtocol =	0,
	/* .iInterface = DYNAMIC */
};

/* full speed support: */

static struct usb_endpoint_descriptor gser_fs_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,
	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor gser_fs_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,
	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
};

static struct usb_descriptor_header *gser_fs_function[] = {
	(struct usb_descriptor_header *) &gser_interface_desc,
	(struct usb_descriptor_header *) &gser_fs_in_desc,
	(struct usb_descriptor_header *) &gser_fs_out_desc,
	NULL,
};

/* high speed support: */

static struct usb_endpoint_descriptor gser_hs_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_endpoint_descriptor gser_hs_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_descriptor_header *gser_hs_function[] = {
	(struct usb_descriptor_header *) &gser_interface_desc,
	(struct usb_descriptor_header *) &gser_hs_in_desc,
	(struct usb_descriptor_header *) &gser_hs_out_desc,
	NULL,
};

static struct usb_endpoint_descriptor gser_ss_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

static struct usb_endpoint_descriptor gser_ss_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
	.bLength =              sizeof gser_ss_bulk_comp_desc,
	.bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
};

static struct usb_descriptor_header *gser_ss_function[] = {
	(struct usb_descriptor_header *) &gser_interface_desc,
	(struct usb_descriptor_header *) &gser_ss_in_desc,
	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
	(struct usb_descriptor_header *) &gser_ss_out_desc,
	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
	NULL,
};

/* string descriptors: */

static struct usb_string gser_string_defs[] = {
	[0].s = "Generic Serial",
	{  } /* end of list */
};

static struct usb_gadget_strings gser_string_table = {
	.language =		0x0409,	/* en-us */
	.strings =		gser_string_defs,
};

static struct usb_gadget_strings *gser_strings[] = {
	&gser_string_table,
	NULL,
};

/*-------------------------------------------------------------------------*/

static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
	struct f_gser		*gser = func_to_gser(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	/* we know alt == 0, so this is an activation or a reset */

	if (gser->port.in->driver_data) {
		dev_dbg(&cdev->gadget->dev,
			"reset generic ttyGS%d\n", gser->port_num);
		gserial_disconnect(&gser->port);
	}
	if (!gser->port.in->desc || !gser->port.out->desc) {
		dev_dbg(&cdev->gadget->dev,
			"activate generic ttyGS%d\n", gser->port_num);
		if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
		    config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
			gser->port.in->desc = NULL;
			gser->port.out->desc = NULL;
			return -EINVAL;
		}
	}
	gserial_connect(&gser->port, gser->port_num);
	return 0;
}

static void gser_disable(struct usb_function *f)
{
	struct f_gser	*gser = func_to_gser(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	dev_dbg(&cdev->gadget->dev,
		"generic ttyGS%d deactivated\n", gser->port_num);
	gserial_disconnect(&gser->port);
}

/*-------------------------------------------------------------------------*/

/* serial function driver setup/binding */

static int gser_bind(struct usb_configuration *c, struct usb_function *f)
{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_gser		*gser = func_to_gser(f);
	int			status;
	struct usb_ep		*ep;

	/* REVISIT might want instance-specific strings to help
	 * distinguish instances ...
	 */

	/* maybe allocate device-global string ID */
	if (gser_string_defs[0].id == 0) {
		status = usb_string_id(c->cdev);
		if (status < 0)
			return status;
		gser_string_defs[0].id = status;
	}

	/* allocate instance-specific interface IDs */
	status = usb_interface_id(c, f);
	if (status < 0)
		goto fail;
	gser->data_id = status;
	gser_interface_desc.bInterfaceNumber = status;

	status = -ENODEV;

	/* allocate instance-specific endpoints */
	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
	if (!ep)
		goto fail;
	gser->port.in = ep;
	ep->driver_data = cdev;	/* claim */

	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
	if (!ep)
		goto fail;
	gser->port.out = ep;
	ep->driver_data = cdev;	/* claim */

	/* support all relevant hardware speeds... we expect that when
	 * hardware is dual speed, all bulk-capable endpoints work at
	 * both speeds
	 */
	gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
	gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;

	gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
	gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;

	status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
			gser_ss_function);
	if (status)
		goto fail;
	dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
		gser->port_num,
		gadget_is_superspeed(c->cdev->gadget) ? "super" :
		gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
		gser->port.in->name, gser->port.out->name);
	return 0;

fail:
	/* we might as well release our claims on endpoints */
	if (gser->port.out)
		gser->port.out->driver_data = NULL;
	if (gser->port.in)
		gser->port.in->driver_data = NULL;

	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);

	return status;
}

static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
{
	return container_of(to_config_group(item), struct f_serial_opts,
			    func_inst.group);
}

CONFIGFS_ATTR_STRUCT(f_serial_opts);
static ssize_t f_serial_attr_show(struct config_item *item,
				  struct configfs_attribute *attr,
				  char *page)
{
	struct f_serial_opts *opts = to_f_serial_opts(item);
	struct f_serial_opts_attribute *f_serial_opts_attr =
		container_of(attr, struct f_serial_opts_attribute, attr);
	ssize_t ret = 0;

	if (f_serial_opts_attr->show)
		ret = f_serial_opts_attr->show(opts, page);

	return ret;
}

static void serial_attr_release(struct config_item *item)
{
	struct f_serial_opts *opts = to_f_serial_opts(item);

	usb_put_function_instance(&opts->func_inst);
}

static struct configfs_item_operations serial_item_ops = {
	.release	= serial_attr_release,
	.show_attribute = f_serial_attr_show,
};

static ssize_t f_serial_port_num_show(struct f_serial_opts *opts, char *page)
{
	return sprintf(page, "%u\n", opts->port_num);
}

static struct f_serial_opts_attribute f_serial_port_num =
	__CONFIGFS_ATTR_RO(port_num, f_serial_port_num_show);

static struct configfs_attribute *acm_attrs[] = {
	&f_serial_port_num.attr,
	NULL,
};

static struct config_item_type serial_func_type = {
	.ct_item_ops	= &serial_item_ops,
	.ct_attrs	= acm_attrs,
	.ct_owner	= THIS_MODULE,
};

static void gser_free_inst(struct usb_function_instance *f)
{
	struct f_serial_opts *opts;

	opts = container_of(f, struct f_serial_opts, func_inst);
	gserial_free_line(opts->port_num);
	kfree(opts);
}

static struct usb_function_instance *gser_alloc_inst(void)
{
	struct f_serial_opts *opts;
	int ret;

	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
	if (!opts)
		return ERR_PTR(-ENOMEM);

	opts->func_inst.free_func_inst = gser_free_inst;
	ret = gserial_alloc_line(&opts->port_num);
	if (ret) {
		kfree(opts);
		return ERR_PTR(ret);
	}
	config_group_init_type_name(&opts->func_inst.group, "",
				    &serial_func_type);

	return &opts->func_inst;
}

static void gser_free(struct usb_function *f)
{
	struct f_gser *serial;

	serial = func_to_gser(f);
	kfree(serial);
}

static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
{
	usb_free_all_descriptors(f);
}

static struct usb_function *gser_alloc(struct usb_function_instance *fi)
{
	struct f_gser	*gser;
	struct f_serial_opts *opts;

	/* allocate and initialize one new instance */
	gser = kzalloc(sizeof(*gser), GFP_KERNEL);
	if (!gser)
		return ERR_PTR(-ENOMEM);

	opts = container_of(fi, struct f_serial_opts, func_inst);

	gser->port_num = opts->port_num;

	gser->port.func.name = "gser";
	gser->port.func.strings = gser_strings;
	gser->port.func.bind = gser_bind;
	gser->port.func.unbind = gser_unbind;
	gser->port.func.set_alt = gser_set_alt;
	gser->port.func.disable = gser_disable;
	gser->port.func.free_func = gser_free;

	return &gser->port.func;
}

DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Al Borchers");
MODULE_AUTHOR("David Brownell");