aboutsummaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/ether.c
blob: 56c8ecae9bc3213781b762e697ad626c23063e59 (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
/*
 * ether.c -- Ethernet gadget driver, with CDC and non-CDC options
 *
 * Copyright (C) 2003-2005,2008 David Brownell
 * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
 * 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.
 */

/* #define VERBOSE_DEBUG */

#include <linux/kernel.h>

#if defined USB_ETH_RNDIS
#  undef USB_ETH_RNDIS
#endif
#ifdef CONFIG_USB_ETH_RNDIS
#  define USB_ETH_RNDIS y
#endif

#include "u_ether.h"


/*
 * Ethernet gadget driver -- with CDC and non-CDC options
 * Builds on hardware support for a full duplex link.
 *
 * CDC Ethernet is the standard USB solution for sending Ethernet frames
 * using USB.  Real hardware tends to use the same framing protocol but look
 * different for control features.  This driver strongly prefers to use
 * this USB-IF standard as its open-systems interoperability solution;
 * most host side USB stacks (except from Microsoft) support it.
 *
 * This is sometimes called "CDC ECM" (Ethernet Control Model) to support
 * TLA-soup.  "CDC ACM" (Abstract Control Model) is for modems, and a new
 * "CDC EEM" (Ethernet Emulation Model) is starting to spread.
 *
 * There's some hardware that can't talk CDC ECM.  We make that hardware
 * implement a "minimalist" vendor-agnostic CDC core:  same framing, but
 * link-level setup only requires activating the configuration.  Only the
 * endpoint descriptors, and product/vendor IDs, are relevant; no control
 * operations are available.  Linux supports it, but other host operating
 * systems may not.  (This is a subset of CDC Ethernet.)
 *
 * It turns out that if you add a few descriptors to that "CDC Subset",
 * (Windows) host side drivers from MCCI can treat it as one submode of
 * a proprietary scheme called "SAFE" ... without needing to know about
 * specific product/vendor IDs.  So we do that, making it easier to use
 * those MS-Windows drivers.  Those added descriptors make it resemble a
 * CDC MDLM device, but they don't change device behavior at all.  (See
 * MCCI Engineering report 950198 "SAFE Networking Functions".)
 *
 * A third option is also in use.  Rather than CDC Ethernet, or something
 * simpler, Microsoft pushes their own approach: RNDIS.  The published
 * RNDIS specs are ambiguous and appear to be incomplete, and are also
 * needlessly complex.  They borrow more from CDC ACM than CDC ECM.
 */

#define DRIVER_DESC		"Ethernet Gadget"
#define DRIVER_VERSION		"Memorial Day 2008"

#ifdef USB_ETH_RNDIS
#define PREFIX			"RNDIS/"
#else
#define PREFIX			""
#endif

/*
 * This driver aims for interoperability by using CDC ECM unless
 *
 *		can_support_ecm()
 *
 * returns false, in which case it supports the CDC Subset.  By default,
 * that returns true; most hardware has no problems with CDC ECM, that's
 * a good default.  Previous versions of this driver had no default; this
 * version changes that, removing overhead for new controller support.
 *
 *	IF YOUR HARDWARE CAN'T SUPPORT CDC ECM, UPDATE THAT ROUTINE!
 */

static inline bool has_rndis(void)
{
#ifdef	USB_ETH_RNDIS
	return true;
#else
	return false;
#endif
}

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

/*
 * Kbuild is not very cooperative with respect to linking separately
 * compiled library objects into one module.  So for now we won't use
 * separate compilation ... ensuring init/exit sections work to shrink
 * the runtime footprint, and giving us at least some parts of what
 * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
 */
#include "f_ecm.c"
#include "f_subset.c"
#ifdef	USB_ETH_RNDIS
#include "f_rndis.c"
#include "rndis.c"
#endif
#include "f_eem.c"
#include "u_ether.c"

/*-------------------------------------------------------------------------*/
USB_GADGET_COMPOSITE_OPTIONS();

/* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */

/* Thanks to NetChip Technologies for donating this product ID.
 * It's for devices with only CDC Ethernet configurations.
 */
#define CDC_VENDOR_NUM		0x0525	/* NetChip */
#define CDC_PRODUCT_NUM		0xa4a1	/* Linux-USB Ethernet Gadget */

/* For hardware that can't talk CDC, we use the same vendor ID that
 * ARM Linux has used for ethernet-over-usb, both with sa1100 and
 * with pxa250.  We're protocol-compatible, if the host-side drivers
 * use the endpoint descriptors.  bcdDevice (version) is nonzero, so
 * drivers that need to hard-wire endpoint numbers have a hook.
 *
 * The protocol is a minimal subset of CDC Ether, which works on any bulk
 * hardware that's not deeply broken ... even on hardware that can't talk
 * RNDIS (like SA-1100, with no interrupt endpoint, or anything that
 * doesn't handle control-OUT).
 */
#define	SIMPLE_VENDOR_NUM	0x049f
#define	SIMPLE_PRODUCT_NUM	0x505a

/* For hardware that can talk RNDIS and either of the above protocols,
 * use this ID ... the windows INF files will know it.  Unless it's
 * used with CDC Ethernet, Linux 2.4 hosts will need updates to choose
 * the non-RNDIS configuration.
 */
#define RNDIS_VENDOR_NUM	0x0525	/* NetChip */
#define RNDIS_PRODUCT_NUM	0xa4a2	/* Ethernet/RNDIS Gadget */

/* For EEM gadgets */
#define EEM_VENDOR_NUM		0x1d6b	/* Linux Foundation */
#define EEM_PRODUCT_NUM		0x0102	/* EEM Gadget */

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

static struct usb_device_descriptor device_desc = {
	.bLength =		sizeof device_desc,
	.bDescriptorType =	USB_DT_DEVICE,

	.bcdUSB =		cpu_to_le16 (0x0200),

	.bDeviceClass =		USB_CLASS_COMM,
	.bDeviceSubClass =	0,
	.bDeviceProtocol =	0,
	/* .bMaxPacketSize0 = f(hardware) */

	/* Vendor and product id defaults change according to what configs
	 * we support.  (As does bNumConfigurations.)  These values can
	 * also be overridden by module parameters.
	 */
	.idVendor =		cpu_to_le16 (CDC_VENDOR_NUM),
	.idProduct =		cpu_to_le16 (CDC_PRODUCT_NUM),
	/* .bcdDevice = f(hardware) */
	/* .iManufacturer = DYNAMIC */
	/* .iProduct = DYNAMIC */
	/* NO SERIAL NUMBER */
	.bNumConfigurations =	1,
};

static struct usb_otg_descriptor otg_descriptor = {
	.bLength =		sizeof otg_descriptor,
	.bDescriptorType =	USB_DT_OTG,

	/* REVISIT SRP-only hardware is possible, although
	 * it would not be called "OTG" ...
	 */
	.bmAttributes =		USB_OTG_SRP | USB_OTG_HNP,
};

static const struct usb_descriptor_header *otg_desc[] = {
	(struct usb_descriptor_header *) &otg_descriptor,
	NULL,
};

static struct usb_string strings_dev[] = {
	[USB_GADGET_MANUFACTURER_IDX].s = "",
	[USB_GADGET_PRODUCT_IDX].s = PREFIX DRIVER_DESC,
	[USB_GADGET_SERIAL_IDX].s = "",
	{  } /* end of list */
};

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

static struct usb_gadget_strings *dev_strings[] = {
	&stringtab_dev,
	NULL,
};

static u8 hostaddr[ETH_ALEN];
static struct eth_dev *the_dev;
/*-------------------------------------------------------------------------*/

/*
 * We may not have an RNDIS configuration, but if we do it needs to be
 * the first one present.  That's to make Microsoft's drivers happy,
 * and to follow DOCSIS 1.0 (cable modem standard).
 */
static int __init rndis_do_config(struct usb_configuration *c)
{
	/* FIXME alloc iConfiguration string, set it in c->strings */

	if (gadget_is_otg(c->cdev->gadget)) {
		c->descriptors = otg_desc;
		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
	}

	return rndis_bind_config(c, hostaddr, the_dev);
}

static struct usb_configuration rndis_config_driver = {
	.label			= "RNDIS",
	.bConfigurationValue	= 2,
	/* .iConfiguration = DYNAMIC */
	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
};

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

#ifdef CONFIG_USB_ETH_EEM
static bool use_eem = 1;
#else
static bool use_eem;
#endif
module_param(use_eem, bool, 0);
MODULE_PARM_DESC(use_eem, "use CDC EEM mode");

/*
 * We _always_ have an ECM, CDC Subset, or EEM configuration.
 */
static int __init eth_do_config(struct usb_configuration *c)
{
	/* FIXME alloc iConfiguration string, set it in c->strings */

	if (gadget_is_otg(c->cdev->gadget)) {
		c->descriptors = otg_desc;
		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
	}

	if (use_eem)
		return eem_bind_config(c, the_dev);
	else if (can_support_ecm(c->cdev->gadget))
		return ecm_bind_config(c, hostaddr, the_dev);
	else
		return geth_bind_config(c, hostaddr, the_dev);
}

static struct usb_configuration eth_config_driver = {
	/* .label = f(hardware) */
	.bConfigurationValue	= 1,
	/* .iConfiguration = DYNAMIC */
	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
};

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

static int __init eth_bind(struct usb_composite_dev *cdev)
{
	struct usb_gadget	*gadget = cdev->gadget;
	int			status;

	/* set up network link layer */
	the_dev = gether_setup(cdev->gadget, hostaddr);
	if (IS_ERR(the_dev))
		return PTR_ERR(the_dev);

	/* set up main config label and device descriptor */
	if (use_eem) {
		/* EEM */
		eth_config_driver.label = "CDC Ethernet (EEM)";
		device_desc.idVendor = cpu_to_le16(EEM_VENDOR_NUM);
		device_desc.idProduct = cpu_to_le16(EEM_PRODUCT_NUM);
	} else if (can_support_ecm(cdev->gadget)) {
		/* ECM */
		eth_config_driver.label = "CDC Ethernet (ECM)";
	} else {
		/* CDC Subset */
		eth_config_driver.label = "CDC Subset/SAFE";

		device_desc.idVendor = cpu_to_le16(SIMPLE_VENDOR_NUM);
		device_desc.idProduct = cpu_to_le16(SIMPLE_PRODUCT_NUM);
		if (!has_rndis())
			device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
	}

	if (has_rndis()) {
		/* RNDIS plus ECM-or-Subset */
		device_desc.idVendor = cpu_to_le16(RNDIS_VENDOR_NUM);
		device_desc.idProduct = cpu_to_le16(RNDIS_PRODUCT_NUM);
		device_desc.bNumConfigurations = 2;
	}

	/* Allocate string descriptor numbers ... note that string
	 * contents can be overridden by the composite_dev glue.
	 */

	status = usb_string_ids_tab(cdev, strings_dev);
	if (status < 0)
		goto fail;
	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;

	/* register our configuration(s); RNDIS first, if it's used */
	if (has_rndis()) {
		status = usb_add_config(cdev, &rndis_config_driver,
				rndis_do_config);
		if (status < 0)
			goto fail;
	}

	status = usb_add_config(cdev, &eth_config_driver, eth_do_config);
	if (status < 0)
		goto fail;

	usb_composite_overwrite_options(cdev, &coverwrite);
	dev_info(&gadget->dev, "%s, version: " DRIVER_VERSION "\n",
			DRIVER_DESC);

	return 0;

fail:
	gether_cleanup(the_dev);
	return status;
}

static int __exit eth_unbind(struct usb_composite_dev *cdev)
{
	gether_cleanup(the_dev);
	return 0;
}

static __refdata struct usb_composite_driver eth_driver = {
	.name		= "g_ether",
	.dev		= &device_desc,
	.strings	= dev_strings,
	.max_speed	= USB_SPEED_SUPER,
	.bind		= eth_bind,
	.unbind		= __exit_p(eth_unbind),
};

MODULE_DESCRIPTION(PREFIX DRIVER_DESC);
MODULE_AUTHOR("David Brownell, Benedikt Spanger");
MODULE_LICENSE("GPL");

static int __init init(void)
{
	return usb_composite_probe(&eth_driver);
}
module_init(init);

static void __exit cleanup(void)
{
	usb_composite_unregister(&eth_driver);
}
module_exit(cleanup);