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