summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/f_subset.c
blob: f1a59190ac9a0b2ad002ca5a0ebcd3d9668126b6 (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
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
/*
 * f_subset.c -- "CDC Subset" Ethernet link function driver
 *
 * Copyright (C) 2003-2005,2008 David Brownell
 * Copyright (C) 2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the 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 <linux/etherdevice.h>

#include "u_ether.h"
#include "u_ether_configfs.h"
#include "u_gether.h"

/*
 * This function packages a simple "CDC Subset" Ethernet port with no real
 * control mechanisms; just raw data transfer over two bulk endpoints.
 * The data transfer model is exactly that of CDC Ethernet, which is
 * why we call it the "CDC Subset".
 *
 * Because it's not standardized, this has some interoperability issues.
 * They mostly relate to driver binding, since the data transfer model is
 * so simple (CDC Ethernet).  The original versions of this protocol used
 * specific product/vendor IDs:  byteswapped IDs for Digital Equipment's
 * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
 * daughtercards with USB peripheral connectors.  (It was used more often
 * with other boards, using the Itsy identifiers.)  Linux hosts recognized
 * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
 * and one interface.
 *
 * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
 * "SAFE", which happens to have a mode which is identical to the "CDC
 * Subset" in terms of data transfer and lack of control model.  This was
 * adopted by later Sharp Zaurus models, and by some other software which
 * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
 *
 * Because Microsoft's RNDIS drivers are far from robust, we added a few
 * descriptors to the CDC Subset code, making this code look like a SAFE
 * implementation.  This lets you use MCCI's host side MS-Windows drivers
 * if you get fed up with RNDIS.  It also makes it easier for composite
 * drivers to work, since they can use class based binding instead of
 * caring about specific product and vendor IDs.
 */

struct f_gether {
	struct gether			port;

	char				ethaddr[14];
};

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

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

/*
 * "Simple" CDC-subset option is a simple vendor-neutral model that most
 * full speed controllers can handle:  one interface, two bulk endpoints.
 * To assist host side drivers, we fancy it up a bit, and add descriptors so
 * some host side drivers will understand it as a "SAFE" variant.
 *
 * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
 * Data endpoints live in the control interface, there's no data interface.
 * And it's not used to talk to a cell phone radio.
 */

/* interface descriptor: */

static struct usb_interface_descriptor subset_data_intf = {
	.bLength =		sizeof subset_data_intf,
	.bDescriptorType =	USB_DT_INTERFACE,

	/* .bInterfaceNumber = DYNAMIC */
	.bAlternateSetting =	0,
	.bNumEndpoints =	2,
	.bInterfaceClass =      USB_CLASS_COMM,
	.bInterfaceSubClass =	USB_CDC_SUBCLASS_MDLM,
	.bInterfaceProtocol =	0,
	/* .iInterface = DYNAMIC */
};

static struct usb_cdc_header_desc mdlm_header_desc = {
	.bLength =		sizeof mdlm_header_desc,
	.bDescriptorType =	USB_DT_CS_INTERFACE,
	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,

	.bcdCDC =		cpu_to_le16(0x0110),
};

static struct usb_cdc_mdlm_desc mdlm_desc = {
	.bLength =		sizeof mdlm_desc,
	.bDescriptorType =	USB_DT_CS_INTERFACE,
	.bDescriptorSubType =	USB_CDC_MDLM_TYPE,

	.bcdVersion =		cpu_to_le16(0x0100),
	.bGUID = {
		0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
		0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
	},
};

/* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
 * can't really use its struct.  All we do here is say that we're using
 * the submode of "SAFE" which directly matches the CDC Subset.
 */
static u8 mdlm_detail_desc[] = {
	6,
	USB_DT_CS_INTERFACE,
	USB_CDC_MDLM_DETAIL_TYPE,

	0,	/* "SAFE" */
	0,	/* network control capabilities (none) */
	0,	/* network data capabilities ("raw" encapsulation) */
};

static struct usb_cdc_ether_desc ether_desc = {
	.bLength =		sizeof ether_desc,
	.bDescriptorType =	USB_DT_CS_INTERFACE,
	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,

	/* this descriptor actually adds value, surprise! */
	/* .iMACAddress = DYNAMIC */
	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
	.wMaxSegmentSize =	cpu_to_le16(ETH_FRAME_LEN),
	.wNumberMCFilters =	cpu_to_le16(0),
	.bNumberPowerFilters =	0,
};

/* full speed support: */

static struct usb_endpoint_descriptor fs_subset_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 fs_subset_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 *fs_eth_function[] = {
	(struct usb_descriptor_header *) &subset_data_intf,
	(struct usb_descriptor_header *) &mdlm_header_desc,
	(struct usb_descriptor_header *) &mdlm_desc,
	(struct usb_descriptor_header *) &mdlm_detail_desc,
	(struct usb_descriptor_header *) &ether_desc,
	(struct usb_descriptor_header *) &fs_subset_in_desc,
	(struct usb_descriptor_header *) &fs_subset_out_desc,
	NULL,
};

/* high speed support: */

static struct usb_endpoint_descriptor hs_subset_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 hs_subset_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 *hs_eth_function[] = {
	(struct usb_descriptor_header *) &subset_data_intf,
	(struct usb_descriptor_header *) &mdlm_header_desc,
	(struct usb_descriptor_header *) &mdlm_desc,
	(struct usb_descriptor_header *) &mdlm_detail_desc,
	(struct usb_descriptor_header *) &ether_desc,
	(struct usb_descriptor_header *) &hs_subset_in_desc,
	(struct usb_descriptor_header *) &hs_subset_out_desc,
	NULL,
};

/* super speed support: */

static struct usb_endpoint_descriptor ss_subset_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 ss_subset_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 ss_subset_bulk_comp_desc = {
	.bLength =		sizeof ss_subset_bulk_comp_desc,
	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,

	/* the following 2 values can be tweaked if necessary */
	/* .bMaxBurst =		0, */
	/* .bmAttributes =	0, */
};

static struct usb_descriptor_header *ss_eth_function[] = {
	(struct usb_descriptor_header *) &subset_data_intf,
	(struct usb_descriptor_header *) &mdlm_header_desc,
	(struct usb_descriptor_header *) &mdlm_desc,
	(struct usb_descriptor_header *) &mdlm_detail_desc,
	(struct usb_descriptor_header *) &ether_desc,
	(struct usb_descriptor_header *) &ss_subset_in_desc,
	(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
	(struct usb_descriptor_header *) &ss_subset_out_desc,
	(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
	NULL,
};

/* string descriptors: */

static struct usb_string geth_string_defs[] = {
	[0].s = "CDC Ethernet Subset/SAFE",
	[1].s = "",
	{  } /* end of list */
};

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

static struct usb_gadget_strings *geth_strings[] = {
	&geth_string_table,
	NULL,
};

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

static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
	struct f_gether		*geth = func_to_geth(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct net_device	*net;

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

	if (geth->port.in_ep->driver_data) {
		DBG(cdev, "reset cdc subset\n");
		gether_disconnect(&geth->port);
	}

	DBG(cdev, "init + activate cdc subset\n");
	if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
	    config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
		geth->port.in_ep->desc = NULL;
		geth->port.out_ep->desc = NULL;
		return -EINVAL;
	}

	net = gether_connect(&geth->port);
	return IS_ERR(net) ? PTR_ERR(net) : 0;
}

static void geth_disable(struct usb_function *f)
{
	struct f_gether	*geth = func_to_geth(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	DBG(cdev, "net deactivated\n");
	gether_disconnect(&geth->port);
}

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

/* serial function driver setup/binding */

static int
geth_bind(struct usb_configuration *c, struct usb_function *f)
{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_gether		*geth = func_to_geth(f);
	struct usb_string	*us;
	int			status;
	struct usb_ep		*ep;

	struct f_gether_opts	*gether_opts;

	gether_opts = container_of(f->fi, struct f_gether_opts, func_inst);

	/*
	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
	 * configurations are bound in sequence with list_for_each_entry,
	 * in each configuration its functions are bound in sequence
	 * with list_for_each_entry, so we assume no race condition
	 * with regard to gether_opts->bound access
	 */
	if (!gether_opts->bound) {
		mutex_lock(&gether_opts->lock);
		gether_set_gadget(gether_opts->net, cdev->gadget);
		status = gether_register_netdev(gether_opts->net);
		mutex_unlock(&gether_opts->lock);
		if (status)
			return status;
		gether_opts->bound = true;
	}

	us = usb_gstrings_attach(cdev, geth_strings,
				 ARRAY_SIZE(geth_string_defs));
	if (IS_ERR(us))
		return PTR_ERR(us);

	subset_data_intf.iInterface = us[0].id;
	ether_desc.iMACAddress = us[1].id;

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

	status = -ENODEV;

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

	ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
	if (!ep)
		goto fail;
	geth->port.out_ep = 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
	 */
	hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
	hs_subset_out_desc.bEndpointAddress =
		fs_subset_out_desc.bEndpointAddress;

	ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
	ss_subset_out_desc.bEndpointAddress =
		fs_subset_out_desc.bEndpointAddress;

	status = usb_assign_descriptors(f, fs_eth_function, hs_eth_function,
			ss_eth_function);
	if (status)
		goto fail;

	/* NOTE:  all that is done without knowing or caring about
	 * the network link ... which is unavailable to this code
	 * until we're activated via set_alt().
	 */

	DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
			gadget_is_superspeed(c->cdev->gadget) ? "super" :
			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
			geth->port.in_ep->name, geth->port.out_ep->name);
	return 0;

fail:
	usb_free_all_descriptors(f);
	/* we might as well release our claims on endpoints */
	if (geth->port.out_ep)
		geth->port.out_ep->driver_data = NULL;
	if (geth->port.in_ep)
		geth->port.in_ep->driver_data = NULL;

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

	return status;
}

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

/* f_gether_item_ops */
USB_ETHERNET_CONFIGFS_ITEM(gether);

/* f_gether_opts_dev_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether);

/* f_gether_opts_host_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether);

/* f_gether_opts_qmult */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether);

/* f_gether_opts_ifname */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether);

static struct configfs_attribute *gether_attrs[] = {
	&f_gether_opts_dev_addr.attr,
	&f_gether_opts_host_addr.attr,
	&f_gether_opts_qmult.attr,
	&f_gether_opts_ifname.attr,
	NULL,
};

static struct config_item_type gether_func_type = {
	.ct_item_ops	= &gether_item_ops,
	.ct_attrs	= gether_attrs,
	.ct_owner	= THIS_MODULE,
};

static void geth_free_inst(struct usb_function_instance *f)
{
	struct f_gether_opts *opts;

	opts = container_of(f, struct f_gether_opts, func_inst);
	if (opts->bound)
		gether_cleanup(netdev_priv(opts->net));
	else
		free_netdev(opts->net);
	kfree(opts);
}

static struct usb_function_instance *geth_alloc_inst(void)
{
	struct f_gether_opts *opts;

	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
	if (!opts)
		return ERR_PTR(-ENOMEM);
	mutex_init(&opts->lock);
	opts->func_inst.free_func_inst = geth_free_inst;
	opts->net = gether_setup_default();
	if (IS_ERR(opts->net)) {
		struct net_device *net = opts->net;
		kfree(opts);
		return ERR_CAST(net);
	}

	config_group_init_type_name(&opts->func_inst.group, "",
				    &gether_func_type);

	return &opts->func_inst;
}

static void geth_free(struct usb_function *f)
{
	struct f_gether *eth;

	eth = func_to_geth(f);
	kfree(eth);
}

static void geth_unbind(struct usb_configuration *c, struct usb_function *f)
{
	geth_string_defs[0].id = 0;
	usb_free_all_descriptors(f);
}

static struct usb_function *geth_alloc(struct usb_function_instance *fi)
{
	struct f_gether	*geth;
	struct f_gether_opts *opts;
	int status;

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

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

	mutex_lock(&opts->lock);
	opts->refcnt++;
	/* export host's Ethernet address in CDC format */
	status = gether_get_host_addr_cdc(opts->net, geth->ethaddr,
					  sizeof(geth->ethaddr));
	if (status < 12) {
		kfree(geth);
		mutex_unlock(&opts->lock);
		return ERR_PTR(-EINVAL);
	}
	geth_string_defs[1].s = geth->ethaddr;

	geth->port.ioport = netdev_priv(opts->net);
	mutex_unlock(&opts->lock);
	geth->port.cdc_filter = DEFAULT_FILTER;

	geth->port.func.name = "cdc_subset";
	geth->port.func.bind = geth_bind;
	geth->port.func.unbind = geth_unbind;
	geth->port.func.set_alt = geth_set_alt;
	geth->port.func.disable = geth_disable;
	geth->port.func.free_func = geth_free;

	return &geth->port.func;
}

DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");