1 /*
2 * f_subset.c -- "CDC Subset" Ethernet link function driver
3 *
4 * Copyright (C) 2003-2005,2008 David Brownell
5 * Copyright (C) 2008 Nokia Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include <linux/slab.h>
23 #include <linux/kernel.h>
24 #include <linux/device.h>
25 #include <linux/etherdevice.h>
26
27 #include "u_ether.h"
28
29
30 /*
31 * This function packages a simple "CDC Subset" Ethernet port with no real
32 * control mechanisms; just raw data transfer over two bulk endpoints.
33 * The data transfer model is exactly that of CDC Ethernet, which is
34 * why we call it the "CDC Subset".
35 *
36 * Because it's not standardized, this has some interoperability issues.
37 * They mostly relate to driver binding, since the data transfer model is
38 * so simple (CDC Ethernet). The original versions of this protocol used
39 * specific product/vendor IDs: byteswapped IDs for Digital Equipment's
40 * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
41 * daughtercards with USB peripheral connectors. (It was used more often
42 * with other boards, using the Itsy identifiers.) Linux hosts recognized
43 * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
44 * and one interface.
45 *
46 * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
47 * "SAFE", which happens to have a mode which is identical to the "CDC
48 * Subset" in terms of data transfer and lack of control model. This was
49 * adopted by later Sharp Zaurus models, and by some other software which
50 * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
51 *
52 * Because Microsoft's RNDIS drivers are far from robust, we added a few
53 * descriptors to the CDC Subset code, making this code look like a SAFE
54 * implementation. This lets you use MCCI's host side MS-Windows drivers
55 * if you get fed up with RNDIS. It also makes it easier for composite
56 * drivers to work, since they can use class based binding instead of
57 * caring about specific product and vendor IDs.
58 */
59
60 struct geth_descs {
61 struct usb_endpoint_descriptor *in;
62 struct usb_endpoint_descriptor *out;
63 };
64
65 struct f_gether {
66 struct gether port;
67
68 char ethaddr[14];
69
70 struct geth_descs fs;
71 struct geth_descs hs;
72 };
73
func_to_geth(struct usb_function * f)74 static inline struct f_gether *func_to_geth(struct usb_function *f)
75 {
76 return container_of(f, struct f_gether, port.func);
77 }
78
79 /*-------------------------------------------------------------------------*/
80
81 /*
82 * "Simple" CDC-subset option is a simple vendor-neutral model that most
83 * full speed controllers can handle: one interface, two bulk endpoints.
84 * To assist host side drivers, we fancy it up a bit, and add descriptors so
85 * some host side drivers will understand it as a "SAFE" variant.
86 *
87 * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
88 * Data endpoints live in the control interface, there's no data interface.
89 * And it's not used to talk to a cell phone radio.
90 */
91
92 /* interface descriptor: */
93
94 static struct usb_interface_descriptor subset_data_intf __initdata = {
95 .bLength = sizeof subset_data_intf,
96 .bDescriptorType = USB_DT_INTERFACE,
97
98 /* .bInterfaceNumber = DYNAMIC */
99 .bAlternateSetting = 0,
100 .bNumEndpoints = 2,
101 .bInterfaceClass = USB_CLASS_COMM,
102 .bInterfaceSubClass = USB_CDC_SUBCLASS_MDLM,
103 .bInterfaceProtocol = 0,
104 /* .iInterface = DYNAMIC */
105 };
106
107 static struct usb_cdc_header_desc mdlm_header_desc __initdata = {
108 .bLength = sizeof mdlm_header_desc,
109 .bDescriptorType = USB_DT_CS_INTERFACE,
110 .bDescriptorSubType = USB_CDC_HEADER_TYPE,
111
112 .bcdCDC = cpu_to_le16(0x0110),
113 };
114
115 static struct usb_cdc_mdlm_desc mdlm_desc __initdata = {
116 .bLength = sizeof mdlm_desc,
117 .bDescriptorType = USB_DT_CS_INTERFACE,
118 .bDescriptorSubType = USB_CDC_MDLM_TYPE,
119
120 .bcdVersion = cpu_to_le16(0x0100),
121 .bGUID = {
122 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
123 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
124 },
125 };
126
127 /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
128 * can't really use its struct. All we do here is say that we're using
129 * the submode of "SAFE" which directly matches the CDC Subset.
130 */
131 static u8 mdlm_detail_desc[] __initdata = {
132 6,
133 USB_DT_CS_INTERFACE,
134 USB_CDC_MDLM_DETAIL_TYPE,
135
136 0, /* "SAFE" */
137 0, /* network control capabilities (none) */
138 0, /* network data capabilities ("raw" encapsulation) */
139 };
140
141 static struct usb_cdc_ether_desc ether_desc __initdata = {
142 .bLength = sizeof ether_desc,
143 .bDescriptorType = USB_DT_CS_INTERFACE,
144 .bDescriptorSubType = USB_CDC_ETHERNET_TYPE,
145
146 /* this descriptor actually adds value, surprise! */
147 /* .iMACAddress = DYNAMIC */
148 .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
149 .wMaxSegmentSize = cpu_to_le16(ETH_FRAME_LEN),
150 .wNumberMCFilters = cpu_to_le16(0),
151 .bNumberPowerFilters = 0,
152 };
153
154 /* full speed support: */
155
156 static struct usb_endpoint_descriptor fs_subset_in_desc __initdata = {
157 .bLength = USB_DT_ENDPOINT_SIZE,
158 .bDescriptorType = USB_DT_ENDPOINT,
159
160 .bEndpointAddress = USB_DIR_IN,
161 .bmAttributes = USB_ENDPOINT_XFER_BULK,
162 };
163
164 static struct usb_endpoint_descriptor fs_subset_out_desc __initdata = {
165 .bLength = USB_DT_ENDPOINT_SIZE,
166 .bDescriptorType = USB_DT_ENDPOINT,
167
168 .bEndpointAddress = USB_DIR_OUT,
169 .bmAttributes = USB_ENDPOINT_XFER_BULK,
170 };
171
172 static struct usb_descriptor_header *fs_eth_function[] __initdata = {
173 (struct usb_descriptor_header *) &subset_data_intf,
174 (struct usb_descriptor_header *) &mdlm_header_desc,
175 (struct usb_descriptor_header *) &mdlm_desc,
176 (struct usb_descriptor_header *) &mdlm_detail_desc,
177 (struct usb_descriptor_header *) ðer_desc,
178 (struct usb_descriptor_header *) &fs_subset_in_desc,
179 (struct usb_descriptor_header *) &fs_subset_out_desc,
180 NULL,
181 };
182
183 /* high speed support: */
184
185 static struct usb_endpoint_descriptor hs_subset_in_desc __initdata = {
186 .bLength = USB_DT_ENDPOINT_SIZE,
187 .bDescriptorType = USB_DT_ENDPOINT,
188
189 .bmAttributes = USB_ENDPOINT_XFER_BULK,
190 .wMaxPacketSize = cpu_to_le16(512),
191 };
192
193 static struct usb_endpoint_descriptor hs_subset_out_desc __initdata = {
194 .bLength = USB_DT_ENDPOINT_SIZE,
195 .bDescriptorType = USB_DT_ENDPOINT,
196
197 .bmAttributes = USB_ENDPOINT_XFER_BULK,
198 .wMaxPacketSize = cpu_to_le16(512),
199 };
200
201 static struct usb_descriptor_header *hs_eth_function[] __initdata = {
202 (struct usb_descriptor_header *) &subset_data_intf,
203 (struct usb_descriptor_header *) &mdlm_header_desc,
204 (struct usb_descriptor_header *) &mdlm_desc,
205 (struct usb_descriptor_header *) &mdlm_detail_desc,
206 (struct usb_descriptor_header *) ðer_desc,
207 (struct usb_descriptor_header *) &hs_subset_in_desc,
208 (struct usb_descriptor_header *) &hs_subset_out_desc,
209 NULL,
210 };
211
212 /* string descriptors: */
213
214 static struct usb_string geth_string_defs[] = {
215 [0].s = "CDC Ethernet Subset/SAFE",
216 [1].s = NULL /* DYNAMIC */,
217 { } /* end of list */
218 };
219
220 static struct usb_gadget_strings geth_string_table = {
221 .language = 0x0409, /* en-us */
222 .strings = geth_string_defs,
223 };
224
225 static struct usb_gadget_strings *geth_strings[] = {
226 &geth_string_table,
227 NULL,
228 };
229
230 /*-------------------------------------------------------------------------*/
231
geth_set_alt(struct usb_function * f,unsigned intf,unsigned alt)232 static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
233 {
234 struct f_gether *geth = func_to_geth(f);
235 struct usb_composite_dev *cdev = f->config->cdev;
236 struct net_device *net;
237
238 /* we know alt == 0, so this is an activation or a reset */
239
240 if (geth->port.in_ep->driver_data) {
241 DBG(cdev, "reset cdc subset\n");
242 gether_disconnect(&geth->port);
243 }
244
245 DBG(cdev, "init + activate cdc subset\n");
246 geth->port.in = ep_choose(cdev->gadget,
247 geth->hs.in, geth->fs.in);
248 geth->port.out = ep_choose(cdev->gadget,
249 geth->hs.out, geth->fs.out);
250
251 net = gether_connect(&geth->port);
252 return IS_ERR(net) ? PTR_ERR(net) : 0;
253 }
254
geth_disable(struct usb_function * f)255 static void geth_disable(struct usb_function *f)
256 {
257 struct f_gether *geth = func_to_geth(f);
258 struct usb_composite_dev *cdev = f->config->cdev;
259
260 DBG(cdev, "net deactivated\n");
261 gether_disconnect(&geth->port);
262 }
263
264 /*-------------------------------------------------------------------------*/
265
266 /* serial function driver setup/binding */
267
268 static int __init
geth_bind(struct usb_configuration * c,struct usb_function * f)269 geth_bind(struct usb_configuration *c, struct usb_function *f)
270 {
271 struct usb_composite_dev *cdev = c->cdev;
272 struct f_gether *geth = func_to_geth(f);
273 int status;
274 struct usb_ep *ep;
275
276 /* allocate instance-specific interface IDs */
277 status = usb_interface_id(c, f);
278 if (status < 0)
279 goto fail;
280 subset_data_intf.bInterfaceNumber = status;
281
282 status = -ENODEV;
283
284 /* allocate instance-specific endpoints */
285 ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
286 if (!ep)
287 goto fail;
288 geth->port.in_ep = ep;
289 ep->driver_data = cdev; /* claim */
290
291 ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
292 if (!ep)
293 goto fail;
294 geth->port.out_ep = ep;
295 ep->driver_data = cdev; /* claim */
296
297 /* copy descriptors, and track endpoint copies */
298 f->descriptors = usb_copy_descriptors(fs_eth_function);
299
300 geth->fs.in = usb_find_endpoint(fs_eth_function,
301 f->descriptors, &fs_subset_in_desc);
302 geth->fs.out = usb_find_endpoint(fs_eth_function,
303 f->descriptors, &fs_subset_out_desc);
304
305
306 /* support all relevant hardware speeds... we expect that when
307 * hardware is dual speed, all bulk-capable endpoints work at
308 * both speeds
309 */
310 if (gadget_is_dualspeed(c->cdev->gadget)) {
311 hs_subset_in_desc.bEndpointAddress =
312 fs_subset_in_desc.bEndpointAddress;
313 hs_subset_out_desc.bEndpointAddress =
314 fs_subset_out_desc.bEndpointAddress;
315
316 /* copy descriptors, and track endpoint copies */
317 f->hs_descriptors = usb_copy_descriptors(hs_eth_function);
318
319 geth->hs.in = usb_find_endpoint(hs_eth_function,
320 f->hs_descriptors, &hs_subset_in_desc);
321 geth->hs.out = usb_find_endpoint(hs_eth_function,
322 f->hs_descriptors, &hs_subset_out_desc);
323 }
324
325 /* NOTE: all that is done without knowing or caring about
326 * the network link ... which is unavailable to this code
327 * until we're activated via set_alt().
328 */
329
330 DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
331 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
332 geth->port.in_ep->name, geth->port.out_ep->name);
333 return 0;
334
335 fail:
336 /* we might as well release our claims on endpoints */
337 if (geth->port.out)
338 geth->port.out_ep->driver_data = NULL;
339 if (geth->port.in)
340 geth->port.in_ep->driver_data = NULL;
341
342 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
343
344 return status;
345 }
346
347 static void
geth_unbind(struct usb_configuration * c,struct usb_function * f)348 geth_unbind(struct usb_configuration *c, struct usb_function *f)
349 {
350 if (gadget_is_dualspeed(c->cdev->gadget))
351 usb_free_descriptors(f->hs_descriptors);
352 usb_free_descriptors(f->descriptors);
353 geth_string_defs[1].s = NULL;
354 kfree(func_to_geth(f));
355 }
356
357 /**
358 * geth_bind_config - add CDC Subset network link to a configuration
359 * @c: the configuration to support the network link
360 * @ethaddr: a buffer in which the ethernet address of the host side
361 * side of the link was recorded
362 * Context: single threaded during gadget setup
363 *
364 * Returns zero on success, else negative errno.
365 *
366 * Caller must have called @gether_setup(). Caller is also responsible
367 * for calling @gether_cleanup() before module unload.
368 */
geth_bind_config(struct usb_configuration * c,u8 ethaddr[ETH_ALEN])369 int __init geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
370 {
371 struct f_gether *geth;
372 int status;
373
374 if (!ethaddr)
375 return -EINVAL;
376
377 /* maybe allocate device-global string IDs */
378 if (geth_string_defs[0].id == 0) {
379
380 /* interface label */
381 status = usb_string_id(c->cdev);
382 if (status < 0)
383 return status;
384 geth_string_defs[0].id = status;
385 subset_data_intf.iInterface = status;
386
387 /* MAC address */
388 status = usb_string_id(c->cdev);
389 if (status < 0)
390 return status;
391 geth_string_defs[1].id = status;
392 ether_desc.iMACAddress = status;
393 }
394
395 /* allocate and initialize one new instance */
396 geth = kzalloc(sizeof *geth, GFP_KERNEL);
397 if (!geth)
398 return -ENOMEM;
399
400 /* export host's Ethernet address in CDC format */
401 snprintf(geth->ethaddr, sizeof geth->ethaddr,
402 "%02X%02X%02X%02X%02X%02X",
403 ethaddr[0], ethaddr[1], ethaddr[2],
404 ethaddr[3], ethaddr[4], ethaddr[5]);
405 geth_string_defs[1].s = geth->ethaddr;
406
407 geth->port.cdc_filter = DEFAULT_FILTER;
408
409 geth->port.func.name = "cdc_subset";
410 geth->port.func.strings = geth_strings;
411 geth->port.func.bind = geth_bind;
412 geth->port.func.unbind = geth_unbind;
413 geth->port.func.set_alt = geth_set_alt;
414 geth->port.func.disable = geth_disable;
415
416 status = usb_add_function(c, &geth->port.func);
417 if (status) {
418 geth_string_defs[1].s = NULL;
419 kfree(geth);
420 }
421 return status;
422 }
423