1/*
2 * ether.c -- Ethernet gadget driver, with CDC and non-CDC options
3 *
4 * Copyright (C) 2003-2005,2008 David Brownell
5 * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
6 * Copyright (C) 2008 Nokia Corporation
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 */
13
14/* #define VERBOSE_DEBUG */
15
16#include <linux/kernel.h>
17#include <linux/utsname.h>
18
19
20#if defined USB_ETH_RNDIS
21#  undef USB_ETH_RNDIS
22#endif
23#ifdef CONFIG_USB_ETH_RNDIS
24#  define USB_ETH_RNDIS y
25#endif
26
27#include "u_ether.h"
28
29
30/*
31 * Ethernet gadget driver -- with CDC and non-CDC options
32 * Builds on hardware support for a full duplex link.
33 *
34 * CDC Ethernet is the standard USB solution for sending Ethernet frames
35 * using USB.  Real hardware tends to use the same framing protocol but look
36 * different for control features.  This driver strongly prefers to use
37 * this USB-IF standard as its open-systems interoperability solution;
38 * most host side USB stacks (except from Microsoft) support it.
39 *
40 * This is sometimes called "CDC ECM" (Ethernet Control Model) to support
41 * TLA-soup.  "CDC ACM" (Abstract Control Model) is for modems, and a new
42 * "CDC EEM" (Ethernet Emulation Model) is starting to spread.
43 *
44 * There's some hardware that can't talk CDC ECM.  We make that hardware
45 * implement a "minimalist" vendor-agnostic CDC core:  same framing, but
46 * link-level setup only requires activating the configuration.  Only the
47 * endpoint descriptors, and product/vendor IDs, are relevant; no control
48 * operations are available.  Linux supports it, but other host operating
49 * systems may not.  (This is a subset of CDC Ethernet.)
50 *
51 * It turns out that if you add a few descriptors to that "CDC Subset",
52 * (Windows) host side drivers from MCCI can treat it as one submode of
53 * a proprietary scheme called "SAFE" ... without needing to know about
54 * specific product/vendor IDs.  So we do that, making it easier to use
55 * those MS-Windows drivers.  Those added descriptors make it resemble a
56 * CDC MDLM device, but they don't change device behavior at all.  (See
57 * MCCI Engineering report 950198 "SAFE Networking Functions".)
58 *
59 * A third option is also in use.  Rather than CDC Ethernet, or something
60 * simpler, Microsoft pushes their own approach: RNDIS.  The published
61 * RNDIS specs are ambiguous and appear to be incomplete, and are also
62 * needlessly complex.  They borrow more from CDC ACM than CDC ECM.
63 */
64
65#define DRIVER_DESC		"Ethernet Gadget"
66#define DRIVER_VERSION		"Memorial Day 2008"
67
68#ifdef USB_ETH_RNDIS
69#define PREFIX			"RNDIS/"
70#else
71#define PREFIX			""
72#endif
73
74/*
75 * This driver aims for interoperability by using CDC ECM unless
76 *
77 *		can_support_ecm()
78 *
79 * returns false, in which case it supports the CDC Subset.  By default,
80 * that returns true; most hardware has no problems with CDC ECM, that's
81 * a good default.  Previous versions of this driver had no default; this
82 * version changes that, removing overhead for new controller support.
83 *
84 *	IF YOUR HARDWARE CAN'T SUPPORT CDC ECM, UPDATE THAT ROUTINE!
85 */
86
87static inline bool has_rndis(void)
88{
89#ifdef	USB_ETH_RNDIS
90	return true;
91#else
92	return false;
93#endif
94}
95
96/*-------------------------------------------------------------------------*/
97
98/*
99 * Kbuild is not very cooperative with respect to linking separately
100 * compiled library objects into one module.  So for now we won't use
101 * separate compilation ... ensuring init/exit sections work to shrink
102 * the runtime footprint, and giving us at least some parts of what
103 * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
104 */
105#include "composite.c"
106#include "usbstring.c"
107#include "config.c"
108#include "epautoconf.c"
109
110#include "f_ecm.c"
111#include "f_subset.c"
112#ifdef	USB_ETH_RNDIS
113#include "f_rndis.c"
114#include "rndis.c"
115#endif
116#include "f_eem.c"
117#include "u_ether.c"
118
119/*-------------------------------------------------------------------------*/
120
121/* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
122 * Instead:  allocate your own, using normal USB-IF procedures.
123 */
124
125/* Thanks to NetChip Technologies for donating this product ID.
126 * It's for devices with only CDC Ethernet configurations.
127 */
128#define CDC_VENDOR_NUM		0x0525	/* NetChip */
129#define CDC_PRODUCT_NUM		0xa4a1	/* Linux-USB Ethernet Gadget */
130
131/* For hardware that can't talk CDC, we use the same vendor ID that
132 * ARM Linux has used for ethernet-over-usb, both with sa1100 and
133 * with pxa250.  We're protocol-compatible, if the host-side drivers
134 * use the endpoint descriptors.  bcdDevice (version) is nonzero, so
135 * drivers that need to hard-wire endpoint numbers have a hook.
136 *
137 * The protocol is a minimal subset of CDC Ether, which works on any bulk
138 * hardware that's not deeply broken ... even on hardware that can't talk
139 * RNDIS (like SA-1100, with no interrupt endpoint, or anything that
140 * doesn't handle control-OUT).
141 */
142#define	SIMPLE_VENDOR_NUM	0x049f
143#define	SIMPLE_PRODUCT_NUM	0x505a
144
145/* For hardware that can talk RNDIS and either of the above protocols,
146 * use this ID ... the windows INF files will know it.  Unless it's
147 * used with CDC Ethernet, Linux 2.4 hosts will need updates to choose
148 * the non-RNDIS configuration.
149 */
150#define RNDIS_VENDOR_NUM	0x0525	/* NetChip */
151#define RNDIS_PRODUCT_NUM	0xa4a2	/* Ethernet/RNDIS Gadget */
152
153/* For EEM gadgets */
154#define EEM_VENDOR_NUM		0x1d6b	/* Linux Foundation */
155#define EEM_PRODUCT_NUM		0x0102	/* EEM Gadget */
156
157/*-------------------------------------------------------------------------*/
158
159static struct usb_device_descriptor device_desc = {
160	.bLength =		sizeof device_desc,
161	.bDescriptorType =	USB_DT_DEVICE,
162
163	.bcdUSB =		cpu_to_le16 (0x0200),
164
165	.bDeviceClass =		USB_CLASS_COMM,
166	.bDeviceSubClass =	0,
167	.bDeviceProtocol =	0,
168	/* .bMaxPacketSize0 = f(hardware) */
169
170	/* Vendor and product id defaults change according to what configs
171	 * we support.  (As does bNumConfigurations.)  These values can
172	 * also be overridden by module parameters.
173	 */
174	.idVendor =		cpu_to_le16 (CDC_VENDOR_NUM),
175	.idProduct =		cpu_to_le16 (CDC_PRODUCT_NUM),
176	/* .bcdDevice = f(hardware) */
177	/* .iManufacturer = DYNAMIC */
178	/* .iProduct = DYNAMIC */
179	/* NO SERIAL NUMBER */
180	.bNumConfigurations =	1,
181};
182
183static struct usb_otg_descriptor otg_descriptor = {
184	.bLength =		sizeof otg_descriptor,
185	.bDescriptorType =	USB_DT_OTG,
186
187	/* REVISIT SRP-only hardware is possible, although
188	 * it would not be called "OTG" ...
189	 */
190	.bmAttributes =		USB_OTG_SRP | USB_OTG_HNP,
191};
192
193static const struct usb_descriptor_header *otg_desc[] = {
194	(struct usb_descriptor_header *) &otg_descriptor,
195	NULL,
196};
197
198
199/* string IDs are assigned dynamically */
200
201#define STRING_MANUFACTURER_IDX		0
202#define STRING_PRODUCT_IDX		1
203
204static char manufacturer[50];
205
206static struct usb_string strings_dev[] = {
207	[STRING_MANUFACTURER_IDX].s = manufacturer,
208	[STRING_PRODUCT_IDX].s = PREFIX DRIVER_DESC,
209	{  } /* end of list */
210};
211
212static struct usb_gadget_strings stringtab_dev = {
213	.language	= 0x0409,	/* en-us */
214	.strings	= strings_dev,
215};
216
217static struct usb_gadget_strings *dev_strings[] = {
218	&stringtab_dev,
219	NULL,
220};
221
222static u8 hostaddr[ETH_ALEN];
223
224/*-------------------------------------------------------------------------*/
225
226/*
227 * We may not have an RNDIS configuration, but if we do it needs to be
228 * the first one present.  That's to make Microsoft's drivers happy,
229 * and to follow DOCSIS 1.0 (cable modem standard).
230 */
231static int __init rndis_do_config(struct usb_configuration *c)
232{
233	/* FIXME alloc iConfiguration string, set it in c->strings */
234
235	if (gadget_is_otg(c->cdev->gadget)) {
236		c->descriptors = otg_desc;
237		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
238	}
239
240	return rndis_bind_config(c, hostaddr);
241}
242
243static struct usb_configuration rndis_config_driver = {
244	.label			= "RNDIS",
245	.bConfigurationValue	= 2,
246	/* .iConfiguration = DYNAMIC */
247	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
248};
249
250/*-------------------------------------------------------------------------*/
251
252#ifdef CONFIG_USB_ETH_EEM
253static bool use_eem = 1;
254#else
255static bool use_eem;
256#endif
257module_param(use_eem, bool, 0);
258MODULE_PARM_DESC(use_eem, "use CDC EEM mode");
259
260/*
261 * We _always_ have an ECM, CDC Subset, or EEM configuration.
262 */
263static int __init eth_do_config(struct usb_configuration *c)
264{
265	/* FIXME alloc iConfiguration string, set it in c->strings */
266
267	if (gadget_is_otg(c->cdev->gadget)) {
268		c->descriptors = otg_desc;
269		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
270	}
271
272	if (use_eem)
273		return eem_bind_config(c);
274	else if (can_support_ecm(c->cdev->gadget))
275		return ecm_bind_config(c, hostaddr);
276	else
277		return geth_bind_config(c, hostaddr);
278}
279
280static struct usb_configuration eth_config_driver = {
281	/* .label = f(hardware) */
282	.bConfigurationValue	= 1,
283	/* .iConfiguration = DYNAMIC */
284	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
285};
286
287/*-------------------------------------------------------------------------*/
288
289static int __init eth_bind(struct usb_composite_dev *cdev)
290{
291	int			gcnum;
292	struct usb_gadget	*gadget = cdev->gadget;
293	int			status;
294
295	/* set up network link layer */
296	status = gether_setup(cdev->gadget, hostaddr);
297	if (status < 0)
298		return status;
299
300	/* set up main config label and device descriptor */
301	if (use_eem) {
302		/* EEM */
303		eth_config_driver.label = "CDC Ethernet (EEM)";
304		device_desc.idVendor = cpu_to_le16(EEM_VENDOR_NUM);
305		device_desc.idProduct = cpu_to_le16(EEM_PRODUCT_NUM);
306	} else if (can_support_ecm(cdev->gadget)) {
307		/* ECM */
308		eth_config_driver.label = "CDC Ethernet (ECM)";
309	} else {
310		/* CDC Subset */
311		eth_config_driver.label = "CDC Subset/SAFE";
312
313		device_desc.idVendor = cpu_to_le16(SIMPLE_VENDOR_NUM);
314		device_desc.idProduct = cpu_to_le16(SIMPLE_PRODUCT_NUM);
315		if (!has_rndis())
316			device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
317	}
318
319	if (has_rndis()) {
320		/* RNDIS plus ECM-or-Subset */
321		device_desc.idVendor = cpu_to_le16(RNDIS_VENDOR_NUM);
322		device_desc.idProduct = cpu_to_le16(RNDIS_PRODUCT_NUM);
323		device_desc.bNumConfigurations = 2;
324	}
325
326	gcnum = usb_gadget_controller_number(gadget);
327	if (gcnum >= 0)
328		device_desc.bcdDevice = cpu_to_le16(0x0300 | gcnum);
329	else {
330		/* We assume that can_support_ecm() tells the truth;
331		 * but if the controller isn't recognized at all then
332		 * that assumption is a bit more likely to be wrong.
333		 */
334		dev_warn(&gadget->dev,
335				"controller '%s' not recognized; trying %s\n",
336				gadget->name,
337				eth_config_driver.label);
338		device_desc.bcdDevice =
339			cpu_to_le16(0x0300 | 0x0099);
340	}
341
342
343	/* Allocate string descriptor numbers ... note that string
344	 * contents can be overridden by the composite_dev glue.
345	 */
346
347	/* device descriptor strings: manufacturer, product */
348	snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
349		init_utsname()->sysname, init_utsname()->release,
350		gadget->name);
351	status = usb_string_id(cdev);
352	if (status < 0)
353		goto fail;
354	strings_dev[STRING_MANUFACTURER_IDX].id = status;
355	device_desc.iManufacturer = status;
356
357	status = usb_string_id(cdev);
358	if (status < 0)
359		goto fail;
360	strings_dev[STRING_PRODUCT_IDX].id = status;
361	device_desc.iProduct = status;
362
363	/* register our configuration(s); RNDIS first, if it's used */
364	if (has_rndis()) {
365		status = usb_add_config(cdev, &rndis_config_driver,
366				rndis_do_config);
367		if (status < 0)
368			goto fail;
369	}
370
371	status = usb_add_config(cdev, &eth_config_driver, eth_do_config);
372	if (status < 0)
373		goto fail;
374
375	dev_info(&gadget->dev, "%s, version: " DRIVER_VERSION "\n",
376			DRIVER_DESC);
377
378	return 0;
379
380fail:
381	gether_cleanup();
382	return status;
383}
384
385static int __exit eth_unbind(struct usb_composite_dev *cdev)
386{
387	gether_cleanup();
388	return 0;
389}
390
391static struct usb_composite_driver eth_driver = {
392	.name		= "g_ether",
393	.dev		= &device_desc,
394	.strings	= dev_strings,
395	.max_speed	= USB_SPEED_SUPER,
396	.unbind		= __exit_p(eth_unbind),
397};
398
399MODULE_DESCRIPTION(PREFIX DRIVER_DESC);
400MODULE_AUTHOR("David Brownell, Benedikt Spanger");
401MODULE_LICENSE("GPL");
402
403static int __init init(void)
404{
405	return usb_composite_probe(&eth_driver, eth_bind);
406}
407module_init(init);
408
409static void __exit cleanup(void)
410{
411	usb_composite_unregister(&eth_driver);
412}
413module_exit(cleanup);
414