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
51struct f_gether {
52	struct gether			port;
53
54	char				ethaddr[14];
55};
56
57static 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
77static 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
90static 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
98static 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 */
114static 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
124static 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
139static 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
147static 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
155static 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 *) &ether_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
168static 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
176static 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
184static 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 *) &ether_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
197static 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
205static 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
213static 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
222static 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 *) &ether_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
237static struct usb_string geth_string_defs[] = {
238	[0].s = "CDC Ethernet Subset/SAFE",
239	[1].s = NULL /* DYNAMIC */,
240	{  } /* end of list */
241};
242
243static struct usb_gadget_strings geth_string_table = {
244	.language =		0x0409,	/* en-us */
245	.strings =		geth_string_defs,
246};
247
248static struct usb_gadget_strings *geth_strings[] = {
249	&geth_string_table,
250	NULL,
251};
252
253/*-------------------------------------------------------------------------*/
254
255static 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
280static 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
293static int
294geth_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	/* copy descriptors, and track endpoint copies */
323	f->descriptors = usb_copy_descriptors(fs_eth_function);
324	if (!f->descriptors)
325		goto fail;
326
327	/* support all relevant hardware speeds... we expect that when
328	 * hardware is dual speed, all bulk-capable endpoints work at
329	 * both speeds
330	 */
331	if (gadget_is_dualspeed(c->cdev->gadget)) {
332		hs_subset_in_desc.bEndpointAddress =
333				fs_subset_in_desc.bEndpointAddress;
334		hs_subset_out_desc.bEndpointAddress =
335				fs_subset_out_desc.bEndpointAddress;
336
337		/* copy descriptors, and track endpoint copies */
338		f->hs_descriptors = usb_copy_descriptors(hs_eth_function);
339		if (!f->hs_descriptors)
340			goto fail;
341	}
342
343	if (gadget_is_superspeed(c->cdev->gadget)) {
344		ss_subset_in_desc.bEndpointAddress =
345				fs_subset_in_desc.bEndpointAddress;
346		ss_subset_out_desc.bEndpointAddress =
347				fs_subset_out_desc.bEndpointAddress;
348
349		/* copy descriptors, and track endpoint copies */
350		f->ss_descriptors = usb_copy_descriptors(ss_eth_function);
351		if (!f->ss_descriptors)
352			goto fail;
353	}
354
355	/* NOTE:  all that is done without knowing or caring about
356	 * the network link ... which is unavailable to this code
357	 * until we're activated via set_alt().
358	 */
359
360	DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
361			gadget_is_superspeed(c->cdev->gadget) ? "super" :
362			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
363			geth->port.in_ep->name, geth->port.out_ep->name);
364	return 0;
365
366fail:
367	if (f->descriptors)
368		usb_free_descriptors(f->descriptors);
369	if (f->hs_descriptors)
370		usb_free_descriptors(f->hs_descriptors);
371
372	/* we might as well release our claims on endpoints */
373	if (geth->port.out_ep->desc)
374		geth->port.out_ep->driver_data = NULL;
375	if (geth->port.in_ep->desc)
376		geth->port.in_ep->driver_data = NULL;
377
378	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
379
380	return status;
381}
382
383static void
384geth_unbind(struct usb_configuration *c, struct usb_function *f)
385{
386	if (gadget_is_superspeed(c->cdev->gadget))
387		usb_free_descriptors(f->ss_descriptors);
388	if (gadget_is_dualspeed(c->cdev->gadget))
389		usb_free_descriptors(f->hs_descriptors);
390	usb_free_descriptors(f->descriptors);
391	geth_string_defs[1].s = NULL;
392	kfree(func_to_geth(f));
393}
394
395/**
396 * geth_bind_config - add CDC Subset network link to a configuration
397 * @c: the configuration to support the network link
398 * @ethaddr: a buffer in which the ethernet address of the host side
399 *	side of the link was recorded
400 * Context: single threaded during gadget setup
401 *
402 * Returns zero on success, else negative errno.
403 *
404 * Caller must have called @gether_setup().  Caller is also responsible
405 * for calling @gether_cleanup() before module unload.
406 */
407int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
408{
409	struct f_gether	*geth;
410	int		status;
411
412	if (!ethaddr)
413		return -EINVAL;
414
415	/* maybe allocate device-global string IDs */
416	if (geth_string_defs[0].id == 0) {
417
418		/* interface label */
419		status = usb_string_id(c->cdev);
420		if (status < 0)
421			return status;
422		geth_string_defs[0].id = status;
423		subset_data_intf.iInterface = status;
424
425		/* MAC address */
426		status = usb_string_id(c->cdev);
427		if (status < 0)
428			return status;
429		geth_string_defs[1].id = status;
430		ether_desc.iMACAddress = status;
431	}
432
433	/* allocate and initialize one new instance */
434	geth = kzalloc(sizeof *geth, GFP_KERNEL);
435	if (!geth)
436		return -ENOMEM;
437
438	/* export host's Ethernet address in CDC format */
439	snprintf(geth->ethaddr, sizeof geth->ethaddr,
440		"%02X%02X%02X%02X%02X%02X",
441		ethaddr[0], ethaddr[1], ethaddr[2],
442		ethaddr[3], ethaddr[4], ethaddr[5]);
443	geth_string_defs[1].s = geth->ethaddr;
444
445	geth->port.cdc_filter = DEFAULT_FILTER;
446
447	geth->port.func.name = "cdc_subset";
448	geth->port.func.strings = geth_strings;
449	geth->port.func.bind = geth_bind;
450	geth->port.func.unbind = geth_unbind;
451	geth->port.func.set_alt = geth_set_alt;
452	geth->port.func.disable = geth_disable;
453
454	status = usb_add_function(c, &geth->port.func);
455	if (status) {
456		geth_string_defs[1].s = NULL;
457		kfree(geth);
458	}
459	return status;
460}
461