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
13 #include <linux/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/device.h>
16 #include <linux/etherdevice.h>
17
18 #include "u_ether.h"
19
20
21 /*
22 * This function packages a simple "CDC Subset" Ethernet port with no real
23 * control mechanisms; just raw data transfer over two bulk endpoints.
24 * The data transfer model is exactly that of CDC Ethernet, which is
25 * why we call it the "CDC Subset".
26 *
27 * Because it's not standardized, this has some interoperability issues.
28 * They mostly relate to driver binding, since the data transfer model is
29 * so simple (CDC Ethernet). The original versions of this protocol used
30 * specific product/vendor IDs: byteswapped IDs for Digital Equipment's
31 * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
32 * daughtercards with USB peripheral connectors. (It was used more often
33 * with other boards, using the Itsy identifiers.) Linux hosts recognized
34 * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
35 * and one interface.
36 *
37 * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
38 * "SAFE", which happens to have a mode which is identical to the "CDC
39 * Subset" in terms of data transfer and lack of control model. This was
40 * adopted by later Sharp Zaurus models, and by some other software which
41 * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
42 *
43 * Because Microsoft's RNDIS drivers are far from robust, we added a few
44 * descriptors to the CDC Subset code, making this code look like a SAFE
45 * implementation. This lets you use MCCI's host side MS-Windows drivers
46 * if you get fed up with RNDIS. It also makes it easier for composite
47 * drivers to work, since they can use class based binding instead of
48 * caring about specific product and vendor IDs.
49 */
50
51 struct f_gether {
52 struct gether port;
53
54 char ethaddr[14];
55 };
56
func_to_geth(struct usb_function * f)57 static inline struct f_gether *func_to_geth(struct usb_function *f)
58 {
59 return container_of(f, struct f_gether, port.func);
60 }
61
62 /*-------------------------------------------------------------------------*/
63
64 /*
65 * "Simple" CDC-subset option is a simple vendor-neutral model that most
66 * full speed controllers can handle: one interface, two bulk endpoints.
67 * To assist host side drivers, we fancy it up a bit, and add descriptors so
68 * some host side drivers will understand it as a "SAFE" variant.
69 *
70 * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
71 * Data endpoints live in the control interface, there's no data interface.
72 * And it's not used to talk to a cell phone radio.
73 */
74
75 /* interface descriptor: */
76
77 static struct usb_interface_descriptor subset_data_intf = {
78 .bLength = sizeof subset_data_intf,
79 .bDescriptorType = USB_DT_INTERFACE,
80
81 /* .bInterfaceNumber = DYNAMIC */
82 .bAlternateSetting = 0,
83 .bNumEndpoints = 2,
84 .bInterfaceClass = USB_CLASS_COMM,
85 .bInterfaceSubClass = USB_CDC_SUBCLASS_MDLM,
86 .bInterfaceProtocol = 0,
87 /* .iInterface = DYNAMIC */
88 };
89
90 static struct usb_cdc_header_desc mdlm_header_desc = {
91 .bLength = sizeof mdlm_header_desc,
92 .bDescriptorType = USB_DT_CS_INTERFACE,
93 .bDescriptorSubType = USB_CDC_HEADER_TYPE,
94
95 .bcdCDC = cpu_to_le16(0x0110),
96 };
97
98 static struct usb_cdc_mdlm_desc mdlm_desc = {
99 .bLength = sizeof mdlm_desc,
100 .bDescriptorType = USB_DT_CS_INTERFACE,
101 .bDescriptorSubType = USB_CDC_MDLM_TYPE,
102
103 .bcdVersion = cpu_to_le16(0x0100),
104 .bGUID = {
105 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
106 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
107 },
108 };
109
110 /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
111 * can't really use its struct. All we do here is say that we're using
112 * the submode of "SAFE" which directly matches the CDC Subset.
113 */
114 static u8 mdlm_detail_desc[] = {
115 6,
116 USB_DT_CS_INTERFACE,
117 USB_CDC_MDLM_DETAIL_TYPE,
118
119 0, /* "SAFE" */
120 0, /* network control capabilities (none) */
121 0, /* network data capabilities ("raw" encapsulation) */
122 };
123
124 static struct usb_cdc_ether_desc ether_desc = {
125 .bLength = sizeof ether_desc,
126 .bDescriptorType = USB_DT_CS_INTERFACE,
127 .bDescriptorSubType = USB_CDC_ETHERNET_TYPE,
128
129 /* this descriptor actually adds value, surprise! */
130 /* .iMACAddress = DYNAMIC */
131 .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
132 .wMaxSegmentSize = cpu_to_le16(ETH_FRAME_LEN),
133 .wNumberMCFilters = cpu_to_le16(0),
134 .bNumberPowerFilters = 0,
135 };
136
137 /* full speed support: */
138
139 static struct usb_endpoint_descriptor fs_subset_in_desc = {
140 .bLength = USB_DT_ENDPOINT_SIZE,
141 .bDescriptorType = USB_DT_ENDPOINT,
142
143 .bEndpointAddress = USB_DIR_IN,
144 .bmAttributes = USB_ENDPOINT_XFER_BULK,
145 };
146
147 static struct usb_endpoint_descriptor fs_subset_out_desc = {
148 .bLength = USB_DT_ENDPOINT_SIZE,
149 .bDescriptorType = USB_DT_ENDPOINT,
150
151 .bEndpointAddress = USB_DIR_OUT,
152 .bmAttributes = USB_ENDPOINT_XFER_BULK,
153 };
154
155 static struct usb_descriptor_header *fs_eth_function[] = {
156 (struct usb_descriptor_header *) &subset_data_intf,
157 (struct usb_descriptor_header *) &mdlm_header_desc,
158 (struct usb_descriptor_header *) &mdlm_desc,
159 (struct usb_descriptor_header *) &mdlm_detail_desc,
160 (struct usb_descriptor_header *) ðer_desc,
161 (struct usb_descriptor_header *) &fs_subset_in_desc,
162 (struct usb_descriptor_header *) &fs_subset_out_desc,
163 NULL,
164 };
165
166 /* high speed support: */
167
168 static struct usb_endpoint_descriptor hs_subset_in_desc = {
169 .bLength = USB_DT_ENDPOINT_SIZE,
170 .bDescriptorType = USB_DT_ENDPOINT,
171
172 .bmAttributes = USB_ENDPOINT_XFER_BULK,
173 .wMaxPacketSize = cpu_to_le16(512),
174 };
175
176 static struct usb_endpoint_descriptor hs_subset_out_desc = {
177 .bLength = USB_DT_ENDPOINT_SIZE,
178 .bDescriptorType = USB_DT_ENDPOINT,
179
180 .bmAttributes = USB_ENDPOINT_XFER_BULK,
181 .wMaxPacketSize = cpu_to_le16(512),
182 };
183
184 static struct usb_descriptor_header *hs_eth_function[] = {
185 (struct usb_descriptor_header *) &subset_data_intf,
186 (struct usb_descriptor_header *) &mdlm_header_desc,
187 (struct usb_descriptor_header *) &mdlm_desc,
188 (struct usb_descriptor_header *) &mdlm_detail_desc,
189 (struct usb_descriptor_header *) ðer_desc,
190 (struct usb_descriptor_header *) &hs_subset_in_desc,
191 (struct usb_descriptor_header *) &hs_subset_out_desc,
192 NULL,
193 };
194
195 /* super speed support: */
196
197 static struct usb_endpoint_descriptor ss_subset_in_desc = {
198 .bLength = USB_DT_ENDPOINT_SIZE,
199 .bDescriptorType = USB_DT_ENDPOINT,
200
201 .bmAttributes = USB_ENDPOINT_XFER_BULK,
202 .wMaxPacketSize = cpu_to_le16(1024),
203 };
204
205 static struct usb_endpoint_descriptor ss_subset_out_desc = {
206 .bLength = USB_DT_ENDPOINT_SIZE,
207 .bDescriptorType = USB_DT_ENDPOINT,
208
209 .bmAttributes = USB_ENDPOINT_XFER_BULK,
210 .wMaxPacketSize = cpu_to_le16(1024),
211 };
212
213 static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = {
214 .bLength = sizeof ss_subset_bulk_comp_desc,
215 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
216
217 /* the following 2 values can be tweaked if necessary */
218 /* .bMaxBurst = 0, */
219 /* .bmAttributes = 0, */
220 };
221
222 static struct usb_descriptor_header *ss_eth_function[] = {
223 (struct usb_descriptor_header *) &subset_data_intf,
224 (struct usb_descriptor_header *) &mdlm_header_desc,
225 (struct usb_descriptor_header *) &mdlm_desc,
226 (struct usb_descriptor_header *) &mdlm_detail_desc,
227 (struct usb_descriptor_header *) ðer_desc,
228 (struct usb_descriptor_header *) &ss_subset_in_desc,
229 (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
230 (struct usb_descriptor_header *) &ss_subset_out_desc,
231 (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
232 NULL,
233 };
234
235 /* string descriptors: */
236
237 static struct usb_string geth_string_defs[] = {
238 [0].s = "CDC Ethernet Subset/SAFE",
239 [1].s = "",
240 { } /* end of list */
241 };
242
243 static struct usb_gadget_strings geth_string_table = {
244 .language = 0x0409, /* en-us */
245 .strings = geth_string_defs,
246 };
247
248 static struct usb_gadget_strings *geth_strings[] = {
249 &geth_string_table,
250 NULL,
251 };
252
253 /*-------------------------------------------------------------------------*/
254
geth_set_alt(struct usb_function * f,unsigned intf,unsigned alt)255 static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
256 {
257 struct f_gether *geth = func_to_geth(f);
258 struct usb_composite_dev *cdev = f->config->cdev;
259 struct net_device *net;
260
261 /* we know alt == 0, so this is an activation or a reset */
262
263 if (geth->port.in_ep->driver_data) {
264 DBG(cdev, "reset cdc subset\n");
265 gether_disconnect(&geth->port);
266 }
267
268 DBG(cdev, "init + activate cdc subset\n");
269 if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
270 config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
271 geth->port.in_ep->desc = NULL;
272 geth->port.out_ep->desc = NULL;
273 return -EINVAL;
274 }
275
276 net = gether_connect(&geth->port);
277 return IS_ERR(net) ? PTR_ERR(net) : 0;
278 }
279
geth_disable(struct usb_function * f)280 static void geth_disable(struct usb_function *f)
281 {
282 struct f_gether *geth = func_to_geth(f);
283 struct usb_composite_dev *cdev = f->config->cdev;
284
285 DBG(cdev, "net deactivated\n");
286 gether_disconnect(&geth->port);
287 }
288
289 /*-------------------------------------------------------------------------*/
290
291 /* serial function driver setup/binding */
292
293 static int
geth_bind(struct usb_configuration * c,struct usb_function * f)294 geth_bind(struct usb_configuration *c, struct usb_function *f)
295 {
296 struct usb_composite_dev *cdev = c->cdev;
297 struct f_gether *geth = func_to_geth(f);
298 int status;
299 struct usb_ep *ep;
300
301 /* allocate instance-specific interface IDs */
302 status = usb_interface_id(c, f);
303 if (status < 0)
304 goto fail;
305 subset_data_intf.bInterfaceNumber = status;
306
307 status = -ENODEV;
308
309 /* allocate instance-specific endpoints */
310 ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
311 if (!ep)
312 goto fail;
313 geth->port.in_ep = ep;
314 ep->driver_data = cdev; /* claim */
315
316 ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
317 if (!ep)
318 goto fail;
319 geth->port.out_ep = ep;
320 ep->driver_data = cdev; /* claim */
321
322 /* support all relevant hardware speeds... we expect that when
323 * hardware is dual speed, all bulk-capable endpoints work at
324 * both speeds
325 */
326 hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
327 hs_subset_out_desc.bEndpointAddress =
328 fs_subset_out_desc.bEndpointAddress;
329
330 ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
331 ss_subset_out_desc.bEndpointAddress =
332 fs_subset_out_desc.bEndpointAddress;
333
334 status = usb_assign_descriptors(f, fs_eth_function, hs_eth_function,
335 ss_eth_function);
336 if (status)
337 goto fail;
338
339 /* NOTE: all that is done without knowing or caring about
340 * the network link ... which is unavailable to this code
341 * until we're activated via set_alt().
342 */
343
344 DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
345 gadget_is_superspeed(c->cdev->gadget) ? "super" :
346 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
347 geth->port.in_ep->name, geth->port.out_ep->name);
348 return 0;
349
350 fail:
351 usb_free_all_descriptors(f);
352 /* we might as well release our claims on endpoints */
353 if (geth->port.out_ep)
354 geth->port.out_ep->driver_data = NULL;
355 if (geth->port.in_ep)
356 geth->port.in_ep->driver_data = NULL;
357
358 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
359
360 return status;
361 }
362
363 static void
geth_unbind(struct usb_configuration * c,struct usb_function * f)364 geth_unbind(struct usb_configuration *c, struct usb_function *f)
365 {
366 geth_string_defs[0].id = 0;
367 usb_free_all_descriptors(f);
368 kfree(func_to_geth(f));
369 }
370
371 /**
372 * geth_bind_config - add CDC Subset network link to a configuration
373 * @c: the configuration to support the network link
374 * @ethaddr: a buffer in which the ethernet address of the host side
375 * side of the link was recorded
376 * @dev: eth_dev structure
377 * Context: single threaded during gadget setup
378 *
379 * Returns zero on success, else negative errno.
380 *
381 * Caller must have called @gether_setup(). Caller is also responsible
382 * for calling @gether_cleanup() before module unload.
383 */
geth_bind_config(struct usb_configuration * c,u8 ethaddr[ETH_ALEN],struct eth_dev * dev)384 int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
385 struct eth_dev *dev)
386 {
387 struct f_gether *geth;
388 int status;
389
390 if (!ethaddr)
391 return -EINVAL;
392
393 /* maybe allocate device-global string IDs */
394 if (geth_string_defs[0].id == 0) {
395 status = usb_string_ids_tab(c->cdev, geth_string_defs);
396 if (status < 0)
397 return status;
398 subset_data_intf.iInterface = geth_string_defs[0].id;
399 ether_desc.iMACAddress = geth_string_defs[1].id;
400 }
401
402 /* allocate and initialize one new instance */
403 geth = kzalloc(sizeof *geth, GFP_KERNEL);
404 if (!geth)
405 return -ENOMEM;
406
407 /* export host's Ethernet address in CDC format */
408 snprintf(geth->ethaddr, sizeof geth->ethaddr, "%pm", ethaddr);
409 geth_string_defs[1].s = geth->ethaddr;
410
411 geth->port.ioport = dev;
412 geth->port.cdc_filter = DEFAULT_FILTER;
413
414 geth->port.func.name = "cdc_subset";
415 geth->port.func.strings = geth_strings;
416 geth->port.func.bind = geth_bind;
417 geth->port.func.unbind = geth_unbind;
418 geth->port.func.set_alt = geth_set_alt;
419 geth->port.func.disable = geth_disable;
420
421 status = usb_add_function(c, &geth->port.func);
422 if (status)
423 kfree(geth);
424 return status;
425 }
426