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v6.8
  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * f_subset.c -- "CDC Subset" Ethernet link function driver
  4 *
  5 * Copyright (C) 2003-2005,2008 David Brownell
  6 * Copyright (C) 2008 Nokia Corporation
 
 
 
 
 
  7 */
  8
  9#include <linux/slab.h>
 10#include <linux/kernel.h>
 11#include <linux/module.h>
 12#include <linux/device.h>
 13#include <linux/etherdevice.h>
 14
 15#include "u_ether.h"
 16#include "u_ether_configfs.h"
 17#include "u_gether.h"
 18
 19/*
 20 * This function packages a simple "CDC Subset" Ethernet port with no real
 21 * control mechanisms; just raw data transfer over two bulk endpoints.
 22 * The data transfer model is exactly that of CDC Ethernet, which is
 23 * why we call it the "CDC Subset".
 24 *
 25 * Because it's not standardized, this has some interoperability issues.
 26 * They mostly relate to driver binding, since the data transfer model is
 27 * so simple (CDC Ethernet).  The original versions of this protocol used
 28 * specific product/vendor IDs:  byteswapped IDs for Digital Equipment's
 29 * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
 30 * daughtercards with USB peripheral connectors.  (It was used more often
 31 * with other boards, using the Itsy identifiers.)  Linux hosts recognized
 32 * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
 33 * and one interface.
 34 *
 35 * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
 36 * "SAFE", which happens to have a mode which is identical to the "CDC
 37 * Subset" in terms of data transfer and lack of control model.  This was
 38 * adopted by later Sharp Zaurus models, and by some other software which
 39 * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
 40 *
 41 * Because Microsoft's RNDIS drivers are far from robust, we added a few
 42 * descriptors to the CDC Subset code, making this code look like a SAFE
 43 * implementation.  This lets you use MCCI's host side MS-Windows drivers
 44 * if you get fed up with RNDIS.  It also makes it easier for composite
 45 * drivers to work, since they can use class based binding instead of
 46 * caring about specific product and vendor IDs.
 47 */
 48
 49struct f_gether {
 50	struct gether			port;
 51
 52	char				ethaddr[14];
 53};
 54
 55static inline struct f_gether *func_to_geth(struct usb_function *f)
 56{
 57	return container_of(f, struct f_gether, port.func);
 58}
 59
 60/*-------------------------------------------------------------------------*/
 61
 62/*
 63 * "Simple" CDC-subset option is a simple vendor-neutral model that most
 64 * full speed controllers can handle:  one interface, two bulk endpoints.
 65 * To assist host side drivers, we fancy it up a bit, and add descriptors so
 66 * some host side drivers will understand it as a "SAFE" variant.
 67 *
 68 * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
 69 * Data endpoints live in the control interface, there's no data interface.
 70 * And it's not used to talk to a cell phone radio.
 71 */
 72
 73/* interface descriptor: */
 74
 75static struct usb_interface_descriptor subset_data_intf = {
 76	.bLength =		sizeof subset_data_intf,
 77	.bDescriptorType =	USB_DT_INTERFACE,
 78
 79	/* .bInterfaceNumber = DYNAMIC */
 80	.bAlternateSetting =	0,
 81	.bNumEndpoints =	2,
 82	.bInterfaceClass =      USB_CLASS_COMM,
 83	.bInterfaceSubClass =	USB_CDC_SUBCLASS_MDLM,
 84	.bInterfaceProtocol =	0,
 85	/* .iInterface = DYNAMIC */
 86};
 87
 88static struct usb_cdc_header_desc mdlm_header_desc = {
 89	.bLength =		sizeof mdlm_header_desc,
 90	.bDescriptorType =	USB_DT_CS_INTERFACE,
 91	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
 92
 93	.bcdCDC =		cpu_to_le16(0x0110),
 94};
 95
 96static struct usb_cdc_mdlm_desc mdlm_desc = {
 97	.bLength =		sizeof mdlm_desc,
 98	.bDescriptorType =	USB_DT_CS_INTERFACE,
 99	.bDescriptorSubType =	USB_CDC_MDLM_TYPE,
100
101	.bcdVersion =		cpu_to_le16(0x0100),
102	.bGUID = {
103		0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
104		0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
105	},
106};
107
108/* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
109 * can't really use its struct.  All we do here is say that we're using
110 * the submode of "SAFE" which directly matches the CDC Subset.
111 */
112static u8 mdlm_detail_desc[] = {
113	6,
114	USB_DT_CS_INTERFACE,
115	USB_CDC_MDLM_DETAIL_TYPE,
116
117	0,	/* "SAFE" */
118	0,	/* network control capabilities (none) */
119	0,	/* network data capabilities ("raw" encapsulation) */
120};
121
122static struct usb_cdc_ether_desc ether_desc = {
123	.bLength =		sizeof ether_desc,
124	.bDescriptorType =	USB_DT_CS_INTERFACE,
125	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,
126
127	/* this descriptor actually adds value, surprise! */
128	/* .iMACAddress = DYNAMIC */
129	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
130	.wMaxSegmentSize =	cpu_to_le16(ETH_FRAME_LEN),
131	.wNumberMCFilters =	cpu_to_le16(0),
132	.bNumberPowerFilters =	0,
133};
134
135/* full speed support: */
136
137static struct usb_endpoint_descriptor fs_subset_in_desc = {
138	.bLength =		USB_DT_ENDPOINT_SIZE,
139	.bDescriptorType =	USB_DT_ENDPOINT,
140
141	.bEndpointAddress =	USB_DIR_IN,
142	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
143};
144
145static struct usb_endpoint_descriptor fs_subset_out_desc = {
146	.bLength =		USB_DT_ENDPOINT_SIZE,
147	.bDescriptorType =	USB_DT_ENDPOINT,
148
149	.bEndpointAddress =	USB_DIR_OUT,
150	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
151};
152
153static struct usb_descriptor_header *fs_eth_function[] = {
154	(struct usb_descriptor_header *) &subset_data_intf,
155	(struct usb_descriptor_header *) &mdlm_header_desc,
156	(struct usb_descriptor_header *) &mdlm_desc,
157	(struct usb_descriptor_header *) &mdlm_detail_desc,
158	(struct usb_descriptor_header *) &ether_desc,
159	(struct usb_descriptor_header *) &fs_subset_in_desc,
160	(struct usb_descriptor_header *) &fs_subset_out_desc,
161	NULL,
162};
163
164/* high speed support: */
165
166static struct usb_endpoint_descriptor hs_subset_in_desc = {
167	.bLength =		USB_DT_ENDPOINT_SIZE,
168	.bDescriptorType =	USB_DT_ENDPOINT,
169
170	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
171	.wMaxPacketSize =	cpu_to_le16(512),
172};
173
174static struct usb_endpoint_descriptor hs_subset_out_desc = {
175	.bLength =		USB_DT_ENDPOINT_SIZE,
176	.bDescriptorType =	USB_DT_ENDPOINT,
177
178	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
179	.wMaxPacketSize =	cpu_to_le16(512),
180};
181
182static struct usb_descriptor_header *hs_eth_function[] = {
183	(struct usb_descriptor_header *) &subset_data_intf,
184	(struct usb_descriptor_header *) &mdlm_header_desc,
185	(struct usb_descriptor_header *) &mdlm_desc,
186	(struct usb_descriptor_header *) &mdlm_detail_desc,
187	(struct usb_descriptor_header *) &ether_desc,
188	(struct usb_descriptor_header *) &hs_subset_in_desc,
189	(struct usb_descriptor_header *) &hs_subset_out_desc,
190	NULL,
191};
192
193/* super speed support: */
194
195static struct usb_endpoint_descriptor ss_subset_in_desc = {
196	.bLength =		USB_DT_ENDPOINT_SIZE,
197	.bDescriptorType =	USB_DT_ENDPOINT,
198
199	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
200	.wMaxPacketSize =	cpu_to_le16(1024),
201};
202
203static struct usb_endpoint_descriptor ss_subset_out_desc = {
204	.bLength =		USB_DT_ENDPOINT_SIZE,
205	.bDescriptorType =	USB_DT_ENDPOINT,
206
207	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
208	.wMaxPacketSize =	cpu_to_le16(1024),
209};
210
211static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = {
212	.bLength =		sizeof ss_subset_bulk_comp_desc,
213	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
214
215	/* the following 2 values can be tweaked if necessary */
216	/* .bMaxBurst =		0, */
217	/* .bmAttributes =	0, */
218};
219
220static struct usb_descriptor_header *ss_eth_function[] = {
221	(struct usb_descriptor_header *) &subset_data_intf,
222	(struct usb_descriptor_header *) &mdlm_header_desc,
223	(struct usb_descriptor_header *) &mdlm_desc,
224	(struct usb_descriptor_header *) &mdlm_detail_desc,
225	(struct usb_descriptor_header *) &ether_desc,
226	(struct usb_descriptor_header *) &ss_subset_in_desc,
227	(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
228	(struct usb_descriptor_header *) &ss_subset_out_desc,
229	(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
230	NULL,
231};
232
233/* string descriptors: */
234
235static struct usb_string geth_string_defs[] = {
236	[0].s = "CDC Ethernet Subset/SAFE",
237	[1].s = "",
238	{  } /* end of list */
239};
240
241static struct usb_gadget_strings geth_string_table = {
242	.language =		0x0409,	/* en-us */
243	.strings =		geth_string_defs,
244};
245
246static struct usb_gadget_strings *geth_strings[] = {
247	&geth_string_table,
248	NULL,
249};
250
251/*-------------------------------------------------------------------------*/
252
253static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
254{
255	struct f_gether		*geth = func_to_geth(f);
256	struct usb_composite_dev *cdev = f->config->cdev;
257	struct net_device	*net;
258
259	/* we know alt == 0, so this is an activation or a reset */
260
261	if (geth->port.in_ep->enabled) {
262		DBG(cdev, "reset cdc subset\n");
263		gether_disconnect(&geth->port);
264	}
265
266	DBG(cdev, "init + activate cdc subset\n");
267	if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
268	    config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
269		geth->port.in_ep->desc = NULL;
270		geth->port.out_ep->desc = NULL;
271		return -EINVAL;
272	}
273
274	net = gether_connect(&geth->port);
275	return PTR_ERR_OR_ZERO(net);
276}
277
278static void geth_disable(struct usb_function *f)
279{
280	struct f_gether	*geth = func_to_geth(f);
281	struct usb_composite_dev *cdev = f->config->cdev;
282
283	DBG(cdev, "net deactivated\n");
284	gether_disconnect(&geth->port);
285}
286
287/*-------------------------------------------------------------------------*/
288
289/* serial function driver setup/binding */
290
291static int
292geth_bind(struct usb_configuration *c, struct usb_function *f)
293{
294	struct usb_composite_dev *cdev = c->cdev;
295	struct f_gether		*geth = func_to_geth(f);
296	struct usb_string	*us;
297	int			status;
298	struct usb_ep		*ep;
299
300	struct f_gether_opts	*gether_opts;
301
302	gether_opts = container_of(f->fi, struct f_gether_opts, func_inst);
303
304	/*
305	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
306	 * configurations are bound in sequence with list_for_each_entry,
307	 * in each configuration its functions are bound in sequence
308	 * with list_for_each_entry, so we assume no race condition
309	 * with regard to gether_opts->bound access
310	 */
311	if (!gether_opts->bound) {
312		mutex_lock(&gether_opts->lock);
313		gether_set_gadget(gether_opts->net, cdev->gadget);
314		status = gether_register_netdev(gether_opts->net);
315		mutex_unlock(&gether_opts->lock);
316		if (status)
317			return status;
318		gether_opts->bound = true;
319	}
320
321	us = usb_gstrings_attach(cdev, geth_strings,
322				 ARRAY_SIZE(geth_string_defs));
323	if (IS_ERR(us))
324		return PTR_ERR(us);
325
326	subset_data_intf.iInterface = us[0].id;
327	ether_desc.iMACAddress = us[1].id;
328
329	/* allocate instance-specific interface IDs */
330	status = usb_interface_id(c, f);
331	if (status < 0)
332		goto fail;
333	subset_data_intf.bInterfaceNumber = status;
334
335	status = -ENODEV;
336
337	/* allocate instance-specific endpoints */
338	ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
339	if (!ep)
340		goto fail;
341	geth->port.in_ep = ep;
342
343	ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
344	if (!ep)
345		goto fail;
346	geth->port.out_ep = ep;
347
348	/* support all relevant hardware speeds... we expect that when
349	 * hardware is dual speed, all bulk-capable endpoints work at
350	 * both speeds
351	 */
352	hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
353	hs_subset_out_desc.bEndpointAddress =
354		fs_subset_out_desc.bEndpointAddress;
355
356	ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
357	ss_subset_out_desc.bEndpointAddress =
358		fs_subset_out_desc.bEndpointAddress;
359
360	status = usb_assign_descriptors(f, fs_eth_function, hs_eth_function,
361			ss_eth_function, ss_eth_function);
362	if (status)
363		goto fail;
364
365	/* NOTE:  all that is done without knowing or caring about
366	 * the network link ... which is unavailable to this code
367	 * until we're activated via set_alt().
368	 */
369
370	DBG(cdev, "CDC Subset: IN/%s OUT/%s\n",
 
 
371			geth->port.in_ep->name, geth->port.out_ep->name);
372	return 0;
373
374fail:
375	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
376
377	return status;
378}
379
380static inline struct f_gether_opts *to_f_gether_opts(struct config_item *item)
381{
382	return container_of(to_config_group(item), struct f_gether_opts,
383			    func_inst.group);
384}
385
386/* f_gether_item_ops */
387USB_ETHERNET_CONFIGFS_ITEM(gether);
388
389/* f_gether_opts_dev_addr */
390USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether);
391
392/* f_gether_opts_host_addr */
393USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether);
394
395/* f_gether_opts_qmult */
396USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether);
397
398/* f_gether_opts_ifname */
399USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether);
400
401static struct configfs_attribute *gether_attrs[] = {
402	&gether_opts_attr_dev_addr,
403	&gether_opts_attr_host_addr,
404	&gether_opts_attr_qmult,
405	&gether_opts_attr_ifname,
406	NULL,
407};
408
409static const struct config_item_type gether_func_type = {
410	.ct_item_ops	= &gether_item_ops,
411	.ct_attrs	= gether_attrs,
412	.ct_owner	= THIS_MODULE,
413};
414
415static void geth_free_inst(struct usb_function_instance *f)
416{
417	struct f_gether_opts *opts;
418
419	opts = container_of(f, struct f_gether_opts, func_inst);
420	if (opts->bound)
421		gether_cleanup(netdev_priv(opts->net));
422	else
423		free_netdev(opts->net);
424	kfree(opts);
425}
426
427static struct usb_function_instance *geth_alloc_inst(void)
428{
429	struct f_gether_opts *opts;
430
431	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
432	if (!opts)
433		return ERR_PTR(-ENOMEM);
434	mutex_init(&opts->lock);
435	opts->func_inst.free_func_inst = geth_free_inst;
436	opts->net = gether_setup_default();
437	if (IS_ERR(opts->net)) {
438		struct net_device *net = opts->net;
439		kfree(opts);
440		return ERR_CAST(net);
441	}
442
443	config_group_init_type_name(&opts->func_inst.group, "",
444				    &gether_func_type);
445
446	return &opts->func_inst;
447}
448
449static void geth_free(struct usb_function *f)
450{
451	struct f_gether *eth;
452
453	eth = func_to_geth(f);
454	kfree(eth);
455}
456
457static void geth_unbind(struct usb_configuration *c, struct usb_function *f)
458{
459	geth_string_defs[0].id = 0;
460	usb_free_all_descriptors(f);
461}
462
463static struct usb_function *geth_alloc(struct usb_function_instance *fi)
464{
465	struct f_gether	*geth;
466	struct f_gether_opts *opts;
467	int status;
468
469	/* allocate and initialize one new instance */
470	geth = kzalloc(sizeof(*geth), GFP_KERNEL);
471	if (!geth)
472		return ERR_PTR(-ENOMEM);
473
474	opts = container_of(fi, struct f_gether_opts, func_inst);
475
476	mutex_lock(&opts->lock);
477	opts->refcnt++;
478	/* export host's Ethernet address in CDC format */
479	status = gether_get_host_addr_cdc(opts->net, geth->ethaddr,
480					  sizeof(geth->ethaddr));
481	if (status < 12) {
482		kfree(geth);
483		mutex_unlock(&opts->lock);
484		return ERR_PTR(-EINVAL);
485	}
486	geth_string_defs[1].s = geth->ethaddr;
487
488	geth->port.ioport = netdev_priv(opts->net);
489	mutex_unlock(&opts->lock);
490	geth->port.cdc_filter = DEFAULT_FILTER;
491
492	geth->port.func.name = "cdc_subset";
493	geth->port.func.bind = geth_bind;
494	geth->port.func.unbind = geth_unbind;
495	geth->port.func.set_alt = geth_set_alt;
496	geth->port.func.disable = geth_disable;
497	geth->port.func.free_func = geth_free;
498
499	return &geth->port.func;
500}
501
502DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc);
503MODULE_LICENSE("GPL");
504MODULE_AUTHOR("David Brownell");
v4.6
 
  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/module.h>
 16#include <linux/device.h>
 17#include <linux/etherdevice.h>
 18
 19#include "u_ether.h"
 20#include "u_ether_configfs.h"
 21#include "u_gether.h"
 22
 23/*
 24 * This function packages a simple "CDC Subset" Ethernet port with no real
 25 * control mechanisms; just raw data transfer over two bulk endpoints.
 26 * The data transfer model is exactly that of CDC Ethernet, which is
 27 * why we call it the "CDC Subset".
 28 *
 29 * Because it's not standardized, this has some interoperability issues.
 30 * They mostly relate to driver binding, since the data transfer model is
 31 * so simple (CDC Ethernet).  The original versions of this protocol used
 32 * specific product/vendor IDs:  byteswapped IDs for Digital Equipment's
 33 * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
 34 * daughtercards with USB peripheral connectors.  (It was used more often
 35 * with other boards, using the Itsy identifiers.)  Linux hosts recognized
 36 * this with CONFIG_USB_ARMLINUX; these devices have only one configuration
 37 * and one interface.
 38 *
 39 * At some point, MCCI defined a (nonconformant) CDC MDLM variant called
 40 * "SAFE", which happens to have a mode which is identical to the "CDC
 41 * Subset" in terms of data transfer and lack of control model.  This was
 42 * adopted by later Sharp Zaurus models, and by some other software which
 43 * Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
 44 *
 45 * Because Microsoft's RNDIS drivers are far from robust, we added a few
 46 * descriptors to the CDC Subset code, making this code look like a SAFE
 47 * implementation.  This lets you use MCCI's host side MS-Windows drivers
 48 * if you get fed up with RNDIS.  It also makes it easier for composite
 49 * drivers to work, since they can use class based binding instead of
 50 * caring about specific product and vendor IDs.
 51 */
 52
 53struct f_gether {
 54	struct gether			port;
 55
 56	char				ethaddr[14];
 57};
 58
 59static inline struct f_gether *func_to_geth(struct usb_function *f)
 60{
 61	return container_of(f, struct f_gether, port.func);
 62}
 63
 64/*-------------------------------------------------------------------------*/
 65
 66/*
 67 * "Simple" CDC-subset option is a simple vendor-neutral model that most
 68 * full speed controllers can handle:  one interface, two bulk endpoints.
 69 * To assist host side drivers, we fancy it up a bit, and add descriptors so
 70 * some host side drivers will understand it as a "SAFE" variant.
 71 *
 72 * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways.
 73 * Data endpoints live in the control interface, there's no data interface.
 74 * And it's not used to talk to a cell phone radio.
 75 */
 76
 77/* interface descriptor: */
 78
 79static struct usb_interface_descriptor subset_data_intf = {
 80	.bLength =		sizeof subset_data_intf,
 81	.bDescriptorType =	USB_DT_INTERFACE,
 82
 83	/* .bInterfaceNumber = DYNAMIC */
 84	.bAlternateSetting =	0,
 85	.bNumEndpoints =	2,
 86	.bInterfaceClass =      USB_CLASS_COMM,
 87	.bInterfaceSubClass =	USB_CDC_SUBCLASS_MDLM,
 88	.bInterfaceProtocol =	0,
 89	/* .iInterface = DYNAMIC */
 90};
 91
 92static struct usb_cdc_header_desc mdlm_header_desc = {
 93	.bLength =		sizeof mdlm_header_desc,
 94	.bDescriptorType =	USB_DT_CS_INTERFACE,
 95	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
 96
 97	.bcdCDC =		cpu_to_le16(0x0110),
 98};
 99
100static struct usb_cdc_mdlm_desc mdlm_desc = {
101	.bLength =		sizeof mdlm_desc,
102	.bDescriptorType =	USB_DT_CS_INTERFACE,
103	.bDescriptorSubType =	USB_CDC_MDLM_TYPE,
104
105	.bcdVersion =		cpu_to_le16(0x0100),
106	.bGUID = {
107		0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
108		0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
109	},
110};
111
112/* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
113 * can't really use its struct.  All we do here is say that we're using
114 * the submode of "SAFE" which directly matches the CDC Subset.
115 */
116static u8 mdlm_detail_desc[] = {
117	6,
118	USB_DT_CS_INTERFACE,
119	USB_CDC_MDLM_DETAIL_TYPE,
120
121	0,	/* "SAFE" */
122	0,	/* network control capabilities (none) */
123	0,	/* network data capabilities ("raw" encapsulation) */
124};
125
126static struct usb_cdc_ether_desc ether_desc = {
127	.bLength =		sizeof ether_desc,
128	.bDescriptorType =	USB_DT_CS_INTERFACE,
129	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,
130
131	/* this descriptor actually adds value, surprise! */
132	/* .iMACAddress = DYNAMIC */
133	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
134	.wMaxSegmentSize =	cpu_to_le16(ETH_FRAME_LEN),
135	.wNumberMCFilters =	cpu_to_le16(0),
136	.bNumberPowerFilters =	0,
137};
138
139/* full speed support: */
140
141static struct usb_endpoint_descriptor fs_subset_in_desc = {
142	.bLength =		USB_DT_ENDPOINT_SIZE,
143	.bDescriptorType =	USB_DT_ENDPOINT,
144
145	.bEndpointAddress =	USB_DIR_IN,
146	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
147};
148
149static struct usb_endpoint_descriptor fs_subset_out_desc = {
150	.bLength =		USB_DT_ENDPOINT_SIZE,
151	.bDescriptorType =	USB_DT_ENDPOINT,
152
153	.bEndpointAddress =	USB_DIR_OUT,
154	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
155};
156
157static struct usb_descriptor_header *fs_eth_function[] = {
158	(struct usb_descriptor_header *) &subset_data_intf,
159	(struct usb_descriptor_header *) &mdlm_header_desc,
160	(struct usb_descriptor_header *) &mdlm_desc,
161	(struct usb_descriptor_header *) &mdlm_detail_desc,
162	(struct usb_descriptor_header *) &ether_desc,
163	(struct usb_descriptor_header *) &fs_subset_in_desc,
164	(struct usb_descriptor_header *) &fs_subset_out_desc,
165	NULL,
166};
167
168/* high speed support: */
169
170static struct usb_endpoint_descriptor hs_subset_in_desc = {
171	.bLength =		USB_DT_ENDPOINT_SIZE,
172	.bDescriptorType =	USB_DT_ENDPOINT,
173
174	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
175	.wMaxPacketSize =	cpu_to_le16(512),
176};
177
178static struct usb_endpoint_descriptor hs_subset_out_desc = {
179	.bLength =		USB_DT_ENDPOINT_SIZE,
180	.bDescriptorType =	USB_DT_ENDPOINT,
181
182	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
183	.wMaxPacketSize =	cpu_to_le16(512),
184};
185
186static struct usb_descriptor_header *hs_eth_function[] = {
187	(struct usb_descriptor_header *) &subset_data_intf,
188	(struct usb_descriptor_header *) &mdlm_header_desc,
189	(struct usb_descriptor_header *) &mdlm_desc,
190	(struct usb_descriptor_header *) &mdlm_detail_desc,
191	(struct usb_descriptor_header *) &ether_desc,
192	(struct usb_descriptor_header *) &hs_subset_in_desc,
193	(struct usb_descriptor_header *) &hs_subset_out_desc,
194	NULL,
195};
196
197/* super speed support: */
198
199static struct usb_endpoint_descriptor ss_subset_in_desc = {
200	.bLength =		USB_DT_ENDPOINT_SIZE,
201	.bDescriptorType =	USB_DT_ENDPOINT,
202
203	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
204	.wMaxPacketSize =	cpu_to_le16(1024),
205};
206
207static struct usb_endpoint_descriptor ss_subset_out_desc = {
208	.bLength =		USB_DT_ENDPOINT_SIZE,
209	.bDescriptorType =	USB_DT_ENDPOINT,
210
211	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
212	.wMaxPacketSize =	cpu_to_le16(1024),
213};
214
215static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = {
216	.bLength =		sizeof ss_subset_bulk_comp_desc,
217	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
218
219	/* the following 2 values can be tweaked if necessary */
220	/* .bMaxBurst =		0, */
221	/* .bmAttributes =	0, */
222};
223
224static struct usb_descriptor_header *ss_eth_function[] = {
225	(struct usb_descriptor_header *) &subset_data_intf,
226	(struct usb_descriptor_header *) &mdlm_header_desc,
227	(struct usb_descriptor_header *) &mdlm_desc,
228	(struct usb_descriptor_header *) &mdlm_detail_desc,
229	(struct usb_descriptor_header *) &ether_desc,
230	(struct usb_descriptor_header *) &ss_subset_in_desc,
231	(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
232	(struct usb_descriptor_header *) &ss_subset_out_desc,
233	(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
234	NULL,
235};
236
237/* string descriptors: */
238
239static struct usb_string geth_string_defs[] = {
240	[0].s = "CDC Ethernet Subset/SAFE",
241	[1].s = "",
242	{  } /* end of list */
243};
244
245static struct usb_gadget_strings geth_string_table = {
246	.language =		0x0409,	/* en-us */
247	.strings =		geth_string_defs,
248};
249
250static struct usb_gadget_strings *geth_strings[] = {
251	&geth_string_table,
252	NULL,
253};
254
255/*-------------------------------------------------------------------------*/
256
257static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
258{
259	struct f_gether		*geth = func_to_geth(f);
260	struct usb_composite_dev *cdev = f->config->cdev;
261	struct net_device	*net;
262
263	/* we know alt == 0, so this is an activation or a reset */
264
265	if (geth->port.in_ep->enabled) {
266		DBG(cdev, "reset cdc subset\n");
267		gether_disconnect(&geth->port);
268	}
269
270	DBG(cdev, "init + activate cdc subset\n");
271	if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
272	    config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
273		geth->port.in_ep->desc = NULL;
274		geth->port.out_ep->desc = NULL;
275		return -EINVAL;
276	}
277
278	net = gether_connect(&geth->port);
279	return PTR_ERR_OR_ZERO(net);
280}
281
282static void geth_disable(struct usb_function *f)
283{
284	struct f_gether	*geth = func_to_geth(f);
285	struct usb_composite_dev *cdev = f->config->cdev;
286
287	DBG(cdev, "net deactivated\n");
288	gether_disconnect(&geth->port);
289}
290
291/*-------------------------------------------------------------------------*/
292
293/* serial function driver setup/binding */
294
295static int
296geth_bind(struct usb_configuration *c, struct usb_function *f)
297{
298	struct usb_composite_dev *cdev = c->cdev;
299	struct f_gether		*geth = func_to_geth(f);
300	struct usb_string	*us;
301	int			status;
302	struct usb_ep		*ep;
303
304	struct f_gether_opts	*gether_opts;
305
306	gether_opts = container_of(f->fi, struct f_gether_opts, func_inst);
307
308	/*
309	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
310	 * configurations are bound in sequence with list_for_each_entry,
311	 * in each configuration its functions are bound in sequence
312	 * with list_for_each_entry, so we assume no race condition
313	 * with regard to gether_opts->bound access
314	 */
315	if (!gether_opts->bound) {
316		mutex_lock(&gether_opts->lock);
317		gether_set_gadget(gether_opts->net, cdev->gadget);
318		status = gether_register_netdev(gether_opts->net);
319		mutex_unlock(&gether_opts->lock);
320		if (status)
321			return status;
322		gether_opts->bound = true;
323	}
324
325	us = usb_gstrings_attach(cdev, geth_strings,
326				 ARRAY_SIZE(geth_string_defs));
327	if (IS_ERR(us))
328		return PTR_ERR(us);
329
330	subset_data_intf.iInterface = us[0].id;
331	ether_desc.iMACAddress = us[1].id;
332
333	/* allocate instance-specific interface IDs */
334	status = usb_interface_id(c, f);
335	if (status < 0)
336		goto fail;
337	subset_data_intf.bInterfaceNumber = status;
338
339	status = -ENODEV;
340
341	/* allocate instance-specific endpoints */
342	ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
343	if (!ep)
344		goto fail;
345	geth->port.in_ep = ep;
346
347	ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
348	if (!ep)
349		goto fail;
350	geth->port.out_ep = ep;
351
352	/* support all relevant hardware speeds... we expect that when
353	 * hardware is dual speed, all bulk-capable endpoints work at
354	 * both speeds
355	 */
356	hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
357	hs_subset_out_desc.bEndpointAddress =
358		fs_subset_out_desc.bEndpointAddress;
359
360	ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
361	ss_subset_out_desc.bEndpointAddress =
362		fs_subset_out_desc.bEndpointAddress;
363
364	status = usb_assign_descriptors(f, fs_eth_function, hs_eth_function,
365			ss_eth_function, NULL);
366	if (status)
367		goto fail;
368
369	/* NOTE:  all that is done without knowing or caring about
370	 * the network link ... which is unavailable to this code
371	 * until we're activated via set_alt().
372	 */
373
374	DBG(cdev, "CDC Subset: %s speed IN/%s OUT/%s\n",
375			gadget_is_superspeed(c->cdev->gadget) ? "super" :
376			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
377			geth->port.in_ep->name, geth->port.out_ep->name);
378	return 0;
379
380fail:
381	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
382
383	return status;
384}
385
386static inline struct f_gether_opts *to_f_gether_opts(struct config_item *item)
387{
388	return container_of(to_config_group(item), struct f_gether_opts,
389			    func_inst.group);
390}
391
392/* f_gether_item_ops */
393USB_ETHERNET_CONFIGFS_ITEM(gether);
394
395/* f_gether_opts_dev_addr */
396USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether);
397
398/* f_gether_opts_host_addr */
399USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether);
400
401/* f_gether_opts_qmult */
402USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether);
403
404/* f_gether_opts_ifname */
405USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether);
406
407static struct configfs_attribute *gether_attrs[] = {
408	&gether_opts_attr_dev_addr,
409	&gether_opts_attr_host_addr,
410	&gether_opts_attr_qmult,
411	&gether_opts_attr_ifname,
412	NULL,
413};
414
415static struct config_item_type gether_func_type = {
416	.ct_item_ops	= &gether_item_ops,
417	.ct_attrs	= gether_attrs,
418	.ct_owner	= THIS_MODULE,
419};
420
421static void geth_free_inst(struct usb_function_instance *f)
422{
423	struct f_gether_opts *opts;
424
425	opts = container_of(f, struct f_gether_opts, func_inst);
426	if (opts->bound)
427		gether_cleanup(netdev_priv(opts->net));
428	else
429		free_netdev(opts->net);
430	kfree(opts);
431}
432
433static struct usb_function_instance *geth_alloc_inst(void)
434{
435	struct f_gether_opts *opts;
436
437	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
438	if (!opts)
439		return ERR_PTR(-ENOMEM);
440	mutex_init(&opts->lock);
441	opts->func_inst.free_func_inst = geth_free_inst;
442	opts->net = gether_setup_default();
443	if (IS_ERR(opts->net)) {
444		struct net_device *net = opts->net;
445		kfree(opts);
446		return ERR_CAST(net);
447	}
448
449	config_group_init_type_name(&opts->func_inst.group, "",
450				    &gether_func_type);
451
452	return &opts->func_inst;
453}
454
455static void geth_free(struct usb_function *f)
456{
457	struct f_gether *eth;
458
459	eth = func_to_geth(f);
460	kfree(eth);
461}
462
463static void geth_unbind(struct usb_configuration *c, struct usb_function *f)
464{
465	geth_string_defs[0].id = 0;
466	usb_free_all_descriptors(f);
467}
468
469static struct usb_function *geth_alloc(struct usb_function_instance *fi)
470{
471	struct f_gether	*geth;
472	struct f_gether_opts *opts;
473	int status;
474
475	/* allocate and initialize one new instance */
476	geth = kzalloc(sizeof(*geth), GFP_KERNEL);
477	if (!geth)
478		return ERR_PTR(-ENOMEM);
479
480	opts = container_of(fi, struct f_gether_opts, func_inst);
481
482	mutex_lock(&opts->lock);
483	opts->refcnt++;
484	/* export host's Ethernet address in CDC format */
485	status = gether_get_host_addr_cdc(opts->net, geth->ethaddr,
486					  sizeof(geth->ethaddr));
487	if (status < 12) {
488		kfree(geth);
489		mutex_unlock(&opts->lock);
490		return ERR_PTR(-EINVAL);
491	}
492	geth_string_defs[1].s = geth->ethaddr;
493
494	geth->port.ioport = netdev_priv(opts->net);
495	mutex_unlock(&opts->lock);
496	geth->port.cdc_filter = DEFAULT_FILTER;
497
498	geth->port.func.name = "cdc_subset";
499	geth->port.func.bind = geth_bind;
500	geth->port.func.unbind = geth_unbind;
501	geth->port.func.set_alt = geth_set_alt;
502	geth->port.func.disable = geth_disable;
503	geth->port.func.free_func = geth_free;
504
505	return &geth->port.func;
506}
507
508DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc);
509MODULE_LICENSE("GPL");
510MODULE_AUTHOR("David Brownell");