f_ecm.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * f_ecm.c -- USB CDC Ethernet (ECM) link function driver
  4 *
  5 * Copyright (C) 2003-2005,2008 David Brownell
  6 * Copyright (C) 2008 Nokia Corporation
  7 */
  8
  9/* #define VERBOSE_DEBUG */
 10
 11#include <linux/cleanup.h>
 12#include <linux/slab.h>
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15#include <linux/device.h>
 16#include <linux/etherdevice.h>
 17#include <linux/string_choices.h>
 18
 19#include <linux/usb/gadget.h>
 20
 21#include "u_ether.h"
 22#include "u_ether_configfs.h"
 23#include "u_ecm.h"
 24
 25
 26/*
 27 * This function is a "CDC Ethernet Networking Control Model" (CDC ECM)
 28 * Ethernet link.  The data transfer model is simple (packets sent and
 29 * received over bulk endpoints using normal short packet termination),
 30 * and the control model exposes various data and optional notifications.
 31 *
 32 * ECM is well standardized and (except for Microsoft) supported by most
 33 * operating systems with USB host support.  It's the preferred interop
 34 * solution for Ethernet over USB, at least for firmware based solutions.
 35 * (Hardware solutions tend to be more minimalist.)  A newer and simpler
 36 * "Ethernet Emulation Model" (CDC EEM) hasn't yet caught on.
 37 *
 38 * Note that ECM requires the use of "alternate settings" for its data
 39 * interface.  This means that the set_alt() method has real work to do,
 40 * and also means that a get_alt() method is required.
 41 */
 42
 43
 44enum ecm_notify_state {
 45	ECM_NOTIFY_NONE,		/* don't notify */
 46	ECM_NOTIFY_CONNECT,		/* issue CONNECT next */
 47	ECM_NOTIFY_SPEED,		/* issue SPEED_CHANGE next */
 48};
 49
 50struct f_ecm {
 51	struct gether			port;
 52	u8				ctrl_id, data_id;
 53
 54	char				ethaddr[14];
 55
 56	struct usb_ep			*notify;
 57	struct usb_request		*notify_req;
 58	u8				notify_state;
 59	atomic_t			notify_count;
 60	bool				is_open;
 61
 62	/* FIXME is_open needs some irq-ish locking
 63	 * ... possibly the same as port.ioport
 64	 */
 65};
 66
 67static inline struct f_ecm *func_to_ecm(struct usb_function *f)
 68{
 69	return container_of(f, struct f_ecm, port.func);
 70}
 71
 72/*-------------------------------------------------------------------------*/
 73
 74/*
 75 * Include the status endpoint if we can, even though it's optional.
 76 *
 77 * Use wMaxPacketSize big enough to fit CDC_NOTIFY_SPEED_CHANGE in one
 78 * packet, to simplify cancellation; and a big transfer interval, to
 79 * waste less bandwidth.
 80 *
 81 * Some drivers (like Linux 2.4 cdc-ether!) "need" it to exist even
 82 * if they ignore the connect/disconnect notifications that real aether
 83 * can provide.  More advanced cdc configurations might want to support
 84 * encapsulated commands (vendor-specific, using control-OUT).
 85 */
 86
 87#define ECM_STATUS_INTERVAL_MS		32
 88#define ECM_STATUS_BYTECOUNT		16	/* 8 byte header + data */
 89
 90
 91/* interface descriptor: */
 92
 93static struct usb_interface_assoc_descriptor
 94ecm_iad_descriptor = {
 95	.bLength =		sizeof ecm_iad_descriptor,
 96	.bDescriptorType =	USB_DT_INTERFACE_ASSOCIATION,
 97
 98	/* .bFirstInterface =	DYNAMIC, */
 99	.bInterfaceCount =	2,	/* control + data */
100	.bFunctionClass =	USB_CLASS_COMM,
101	.bFunctionSubClass =	USB_CDC_SUBCLASS_ETHERNET,
102	.bFunctionProtocol =	USB_CDC_PROTO_NONE,
103	/* .iFunction =		DYNAMIC */
104};
105
106
107static struct usb_interface_descriptor ecm_control_intf = {
108	.bLength =		sizeof ecm_control_intf,
109	.bDescriptorType =	USB_DT_INTERFACE,
110
111	/* .bInterfaceNumber = DYNAMIC */
112	/* status endpoint is optional; this could be patched later */
113	.bNumEndpoints =	1,
114	.bInterfaceClass =	USB_CLASS_COMM,
115	.bInterfaceSubClass =	USB_CDC_SUBCLASS_ETHERNET,
116	.bInterfaceProtocol =	USB_CDC_PROTO_NONE,
117	/* .iInterface = DYNAMIC */
118};
119
120static struct usb_cdc_header_desc ecm_header_desc = {
121	.bLength =		sizeof ecm_header_desc,
122	.bDescriptorType =	USB_DT_CS_INTERFACE,
123	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
124
125	.bcdCDC =		cpu_to_le16(0x0110),
126};
127
128static struct usb_cdc_union_desc ecm_union_desc = {
129	.bLength =		sizeof(ecm_union_desc),
130	.bDescriptorType =	USB_DT_CS_INTERFACE,
131	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
132	/* .bMasterInterface0 =	DYNAMIC */
133	/* .bSlaveInterface0 =	DYNAMIC */
134};
135
136static struct usb_cdc_ether_desc ecm_desc = {
137	.bLength =		sizeof ecm_desc,
138	.bDescriptorType =	USB_DT_CS_INTERFACE,
139	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,
140
141	/* this descriptor actually adds value, surprise! */
142	/* .iMACAddress = DYNAMIC */
143	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
144	.wMaxSegmentSize =	cpu_to_le16(ETH_FRAME_LEN),
145	.wNumberMCFilters =	cpu_to_le16(0),
146	.bNumberPowerFilters =	0,
147};
148
149/* the default data interface has no endpoints ... */
150
151static struct usb_interface_descriptor ecm_data_nop_intf = {
152	.bLength =		sizeof ecm_data_nop_intf,
153	.bDescriptorType =	USB_DT_INTERFACE,
154
155	.bInterfaceNumber =	1,
156	.bAlternateSetting =	0,
157	.bNumEndpoints =	0,
158	.bInterfaceClass =	USB_CLASS_CDC_DATA,
159	.bInterfaceSubClass =	0,
160	.bInterfaceProtocol =	0,
161	/* .iInterface = DYNAMIC */
162};
163
164/* ... but the "real" data interface has two bulk endpoints */
165
166static struct usb_interface_descriptor ecm_data_intf = {
167	.bLength =		sizeof ecm_data_intf,
168	.bDescriptorType =	USB_DT_INTERFACE,
169
170	.bInterfaceNumber =	1,
171	.bAlternateSetting =	1,
172	.bNumEndpoints =	2,
173	.bInterfaceClass =	USB_CLASS_CDC_DATA,
174	.bInterfaceSubClass =	0,
175	.bInterfaceProtocol =	0,
176	/* .iInterface = DYNAMIC */
177};
178
179/* full speed support: */
180
181static struct usb_endpoint_descriptor fs_ecm_notify_desc = {
182	.bLength =		USB_DT_ENDPOINT_SIZE,
183	.bDescriptorType =	USB_DT_ENDPOINT,
184
185	.bEndpointAddress =	USB_DIR_IN,
186	.bmAttributes =		USB_ENDPOINT_XFER_INT,
187	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
188	.bInterval =		ECM_STATUS_INTERVAL_MS,
189};
190
191static struct usb_endpoint_descriptor fs_ecm_in_desc = {
192	.bLength =		USB_DT_ENDPOINT_SIZE,
193	.bDescriptorType =	USB_DT_ENDPOINT,
194
195	.bEndpointAddress =	USB_DIR_IN,
196	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
197};
198
199static struct usb_endpoint_descriptor fs_ecm_out_desc = {
200	.bLength =		USB_DT_ENDPOINT_SIZE,
201	.bDescriptorType =	USB_DT_ENDPOINT,
202
203	.bEndpointAddress =	USB_DIR_OUT,
204	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
205};
206
207static struct usb_descriptor_header *ecm_fs_function[] = {
208	/* CDC ECM control descriptors */
209	(struct usb_descriptor_header *) &ecm_iad_descriptor,
210	(struct usb_descriptor_header *) &ecm_control_intf,
211	(struct usb_descriptor_header *) &ecm_header_desc,
212	(struct usb_descriptor_header *) &ecm_union_desc,
213	(struct usb_descriptor_header *) &ecm_desc,
214
215	/* NOTE: status endpoint might need to be removed */
216	(struct usb_descriptor_header *) &fs_ecm_notify_desc,
217
218	/* data interface, altsettings 0 and 1 */
219	(struct usb_descriptor_header *) &ecm_data_nop_intf,
220	(struct usb_descriptor_header *) &ecm_data_intf,
221	(struct usb_descriptor_header *) &fs_ecm_in_desc,
222	(struct usb_descriptor_header *) &fs_ecm_out_desc,
223	NULL,
224};
225
226/* high speed support: */
227
228static struct usb_endpoint_descriptor hs_ecm_notify_desc = {
229	.bLength =		USB_DT_ENDPOINT_SIZE,
230	.bDescriptorType =	USB_DT_ENDPOINT,
231
232	.bEndpointAddress =	USB_DIR_IN,
233	.bmAttributes =		USB_ENDPOINT_XFER_INT,
234	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
235	.bInterval =		USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
236};
237
238static struct usb_endpoint_descriptor hs_ecm_in_desc = {
239	.bLength =		USB_DT_ENDPOINT_SIZE,
240	.bDescriptorType =	USB_DT_ENDPOINT,
241
242	.bEndpointAddress =	USB_DIR_IN,
243	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
244	.wMaxPacketSize =	cpu_to_le16(512),
245};
246
247static struct usb_endpoint_descriptor hs_ecm_out_desc = {
248	.bLength =		USB_DT_ENDPOINT_SIZE,
249	.bDescriptorType =	USB_DT_ENDPOINT,
250
251	.bEndpointAddress =	USB_DIR_OUT,
252	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
253	.wMaxPacketSize =	cpu_to_le16(512),
254};
255
256static struct usb_descriptor_header *ecm_hs_function[] = {
257	/* CDC ECM control descriptors */
258	(struct usb_descriptor_header *) &ecm_iad_descriptor,
259	(struct usb_descriptor_header *) &ecm_control_intf,
260	(struct usb_descriptor_header *) &ecm_header_desc,
261	(struct usb_descriptor_header *) &ecm_union_desc,
262	(struct usb_descriptor_header *) &ecm_desc,
263
264	/* NOTE: status endpoint might need to be removed */
265	(struct usb_descriptor_header *) &hs_ecm_notify_desc,
266
267	/* data interface, altsettings 0 and 1 */
268	(struct usb_descriptor_header *) &ecm_data_nop_intf,
269	(struct usb_descriptor_header *) &ecm_data_intf,
270	(struct usb_descriptor_header *) &hs_ecm_in_desc,
271	(struct usb_descriptor_header *) &hs_ecm_out_desc,
272	NULL,
273};
274
275/* super speed support: */
276
277static struct usb_endpoint_descriptor ss_ecm_notify_desc = {
278	.bLength =		USB_DT_ENDPOINT_SIZE,
279	.bDescriptorType =	USB_DT_ENDPOINT,
280
281	.bEndpointAddress =	USB_DIR_IN,
282	.bmAttributes =		USB_ENDPOINT_XFER_INT,
283	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
284	.bInterval =		USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
285};
286
287static struct usb_ss_ep_comp_descriptor ss_ecm_intr_comp_desc = {
288	.bLength =		sizeof ss_ecm_intr_comp_desc,
289	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
290
291	/* the following 3 values can be tweaked if necessary */
292	/* .bMaxBurst =		0, */
293	/* .bmAttributes =	0, */
294	.wBytesPerInterval =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
295};
296
297static struct usb_endpoint_descriptor ss_ecm_in_desc = {
298	.bLength =		USB_DT_ENDPOINT_SIZE,
299	.bDescriptorType =	USB_DT_ENDPOINT,
300
301	.bEndpointAddress =	USB_DIR_IN,
302	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
303	.wMaxPacketSize =	cpu_to_le16(1024),
304};
305
306static struct usb_endpoint_descriptor ss_ecm_out_desc = {
307	.bLength =		USB_DT_ENDPOINT_SIZE,
308	.bDescriptorType =	USB_DT_ENDPOINT,
309
310	.bEndpointAddress =	USB_DIR_OUT,
311	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
312	.wMaxPacketSize =	cpu_to_le16(1024),
313};
314
315static struct usb_ss_ep_comp_descriptor ss_ecm_bulk_comp_desc = {
316	.bLength =		sizeof ss_ecm_bulk_comp_desc,
317	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
318
319	/* the following 2 values can be tweaked if necessary */
320	/* .bMaxBurst =		0, */
321	/* .bmAttributes =	0, */
322};
323
324static struct usb_descriptor_header *ecm_ss_function[] = {
325	/* CDC ECM control descriptors */
326	(struct usb_descriptor_header *) &ecm_iad_descriptor,
327	(struct usb_descriptor_header *) &ecm_control_intf,
328	(struct usb_descriptor_header *) &ecm_header_desc,
329	(struct usb_descriptor_header *) &ecm_union_desc,
330	(struct usb_descriptor_header *) &ecm_desc,
331
332	/* NOTE: status endpoint might need to be removed */
333	(struct usb_descriptor_header *) &ss_ecm_notify_desc,
334	(struct usb_descriptor_header *) &ss_ecm_intr_comp_desc,
335
336	/* data interface, altsettings 0 and 1 */
337	(struct usb_descriptor_header *) &ecm_data_nop_intf,
338	(struct usb_descriptor_header *) &ecm_data_intf,
339	(struct usb_descriptor_header *) &ss_ecm_in_desc,
340	(struct usb_descriptor_header *) &ss_ecm_bulk_comp_desc,
341	(struct usb_descriptor_header *) &ss_ecm_out_desc,
342	(struct usb_descriptor_header *) &ss_ecm_bulk_comp_desc,
343	NULL,
344};
345
346/* string descriptors: */
347
348static struct usb_string ecm_string_defs[] = {
349	[0].s = "CDC Ethernet Control Model (ECM)",
350	[1].s = "",
351	[2].s = "CDC Ethernet Data",
352	[3].s = "CDC ECM",
353	{  } /* end of list */
354};
355
356static struct usb_gadget_strings ecm_string_table = {
357	.language =		0x0409,	/* en-us */
358	.strings =		ecm_string_defs,
359};
360
361static struct usb_gadget_strings *ecm_strings[] = {
362	&ecm_string_table,
363	NULL,
364};
365
366/*-------------------------------------------------------------------------*/
367
368static void ecm_do_notify(struct f_ecm *ecm)
369{
370	struct usb_request		*req = ecm->notify_req;
371	struct usb_cdc_notification	*event;
372	struct usb_composite_dev	*cdev = ecm->port.func.config->cdev;
373	__le32				*data;
374	int				status;
375
376	/* notification already in flight? */
377	if (atomic_read(&ecm->notify_count))
378		return;
379
380	event = req->buf;
381	switch (ecm->notify_state) {
382	case ECM_NOTIFY_NONE:
383		return;
384
385	case ECM_NOTIFY_CONNECT:
386		event->bNotificationType = USB_CDC_NOTIFY_NETWORK_CONNECTION;
387		if (ecm->is_open)
388			event->wValue = cpu_to_le16(1);
389		else
390			event->wValue = cpu_to_le16(0);
391		event->wLength = 0;
392		req->length = sizeof *event;
393
394		DBG(cdev, "notify connect %s\n", str_true_false(ecm->is_open));
395		ecm->notify_state = ECM_NOTIFY_SPEED;
396		break;
397
398	case ECM_NOTIFY_SPEED:
399		event->bNotificationType = USB_CDC_NOTIFY_SPEED_CHANGE;
400		event->wValue = cpu_to_le16(0);
401		event->wLength = cpu_to_le16(8);
402		req->length = ECM_STATUS_BYTECOUNT;
403
404		/* SPEED_CHANGE data is up/down speeds in bits/sec */
405		data = req->buf + sizeof *event;
406		data[0] = cpu_to_le32(gether_bitrate(cdev->gadget));
407		data[1] = data[0];
408
409		DBG(cdev, "notify speed %d\n", gether_bitrate(cdev->gadget));
410		ecm->notify_state = ECM_NOTIFY_NONE;
411		break;
412	}
413	event->bmRequestType = 0xA1;
414	event->wIndex = cpu_to_le16(ecm->ctrl_id);
415
416	atomic_inc(&ecm->notify_count);
417	status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC);
418	if (status < 0) {
419		atomic_dec(&ecm->notify_count);
420		DBG(cdev, "notify --> %d\n", status);
421	}
422}
423
424static void ecm_notify(struct f_ecm *ecm)
425{
426	/* NOTE on most versions of Linux, host side cdc-ethernet
427	 * won't listen for notifications until its netdevice opens.
428	 * The first notification then sits in the FIFO for a long
429	 * time, and the second one is queued.
430	 */
431	ecm->notify_state = ECM_NOTIFY_CONNECT;
432	ecm_do_notify(ecm);
433}
434
435static void ecm_notify_complete(struct usb_ep *ep, struct usb_request *req)
436{
437	struct f_ecm			*ecm = req->context;
438	struct usb_composite_dev	*cdev = ecm->port.func.config->cdev;
439	struct usb_cdc_notification	*event = req->buf;
440
441	switch (req->status) {
442	case 0:
443		/* no fault */
444		atomic_dec(&ecm->notify_count);
445		break;
446	case -ECONNRESET:
447	case -ESHUTDOWN:
448		atomic_set(&ecm->notify_count, 0);
449		ecm->notify_state = ECM_NOTIFY_NONE;
450		break;
451	default:
452		DBG(cdev, "event %02x --> %d\n",
453			event->bNotificationType, req->status);
454		atomic_dec(&ecm->notify_count);
455		break;
456	}
457	ecm_do_notify(ecm);
458}
459
460static int ecm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
461{
462	struct f_ecm		*ecm = func_to_ecm(f);
463	struct usb_composite_dev *cdev = f->config->cdev;
464	struct usb_request	*req = cdev->req;
465	int			value = -EOPNOTSUPP;
466	u16			w_index = le16_to_cpu(ctrl->wIndex);
467	u16			w_value = le16_to_cpu(ctrl->wValue);
468	u16			w_length = le16_to_cpu(ctrl->wLength);
469
470	/* composite driver infrastructure handles everything except
471	 * CDC class messages; interface activation uses set_alt().
472	 */
473	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
474	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
475			| USB_CDC_SET_ETHERNET_PACKET_FILTER:
476		/* see 6.2.30: no data, wIndex = interface,
477		 * wValue = packet filter bitmap
478		 */
479		if (w_length != 0 || w_index != ecm->ctrl_id)
480			goto invalid;
481		DBG(cdev, "packet filter %02x\n", w_value);
482		/* REVISIT locking of cdc_filter.  This assumes the UDC
483		 * driver won't have a concurrent packet TX irq running on
484		 * another CPU; or that if it does, this write is atomic...
485		 */
486		ecm->port.cdc_filter = w_value;
487		value = 0;
488		break;
489
490	/* and optionally:
491	 * case USB_CDC_SEND_ENCAPSULATED_COMMAND:
492	 * case USB_CDC_GET_ENCAPSULATED_RESPONSE:
493	 * case USB_CDC_SET_ETHERNET_MULTICAST_FILTERS:
494	 * case USB_CDC_SET_ETHERNET_PM_PATTERN_FILTER:
495	 * case USB_CDC_GET_ETHERNET_PM_PATTERN_FILTER:
496	 * case USB_CDC_GET_ETHERNET_STATISTIC:
497	 */
498
499	default:
500invalid:
501		DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
502			ctrl->bRequestType, ctrl->bRequest,
503			w_value, w_index, w_length);
504	}
505
506	/* respond with data transfer or status phase? */
507	if (value >= 0) {
508		DBG(cdev, "ecm req%02x.%02x v%04x i%04x l%d\n",
509			ctrl->bRequestType, ctrl->bRequest,
510			w_value, w_index, w_length);
511		req->zero = 0;
512		req->length = value;
513		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
514		if (value < 0)
515			ERROR(cdev, "ecm req %02x.%02x response err %d\n",
516					ctrl->bRequestType, ctrl->bRequest,
517					value);
518	}
519
520	/* device either stalls (value < 0) or reports success */
521	return value;
522}
523
524
525static int ecm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
526{
527	struct f_ecm		*ecm = func_to_ecm(f);
528	struct usb_composite_dev *cdev = f->config->cdev;
529
530	/* Control interface has only altsetting 0 */
531	if (intf == ecm->ctrl_id) {
532		if (alt != 0)
533			goto fail;
534
535		VDBG(cdev, "reset ecm control %d\n", intf);
536		usb_ep_disable(ecm->notify);
537		if (!(ecm->notify->desc)) {
538			VDBG(cdev, "init ecm ctrl %d\n", intf);
539			if (config_ep_by_speed(cdev->gadget, f, ecm->notify))
540				goto fail;
541		}
542		usb_ep_enable(ecm->notify);
543
544	/* Data interface has two altsettings, 0 and 1 */
545	} else if (intf == ecm->data_id) {
546		if (alt > 1)
547			goto fail;
548
549		if (ecm->port.in_ep->enabled) {
550			DBG(cdev, "reset ecm\n");
551			gether_disconnect(&ecm->port);
552		}
553
554		if (!ecm->port.in_ep->desc ||
555		    !ecm->port.out_ep->desc) {
556			DBG(cdev, "init ecm\n");
557			if (config_ep_by_speed(cdev->gadget, f,
558					       ecm->port.in_ep) ||
559			    config_ep_by_speed(cdev->gadget, f,
560					       ecm->port.out_ep)) {
561				ecm->port.in_ep->desc = NULL;
562				ecm->port.out_ep->desc = NULL;
563				goto fail;
564			}
565		}
566
567		/* CDC Ethernet only sends data in non-default altsettings.
568		 * Changing altsettings resets filters, statistics, etc.
569		 */
570		if (alt == 1) {
571			struct net_device	*net;
572
573			/* Enable zlps by default for ECM conformance;
574			 * override for musb_hdrc (avoids txdma ovhead).
575			 */
576			ecm->port.is_zlp_ok =
577				gadget_is_zlp_supported(cdev->gadget);
578			ecm->port.cdc_filter = DEFAULT_FILTER;
579			DBG(cdev, "activate ecm\n");
580			net = gether_connect(&ecm->port);
581			if (IS_ERR(net))
582				return PTR_ERR(net);
583		}
584
585		/* NOTE this can be a minor disagreement with the ECM spec,
586		 * which says speed notifications will "always" follow
587		 * connection notifications.  But we allow one connect to
588		 * follow another (if the first is in flight), and instead
589		 * just guarantee that a speed notification is always sent.
590		 */
591		ecm_notify(ecm);
592	} else
593		goto fail;
594
595	return 0;
596fail:
597	return -EINVAL;
598}
599
600/* Because the data interface supports multiple altsettings,
601 * this ECM function *MUST* implement a get_alt() method.
602 */
603static int ecm_get_alt(struct usb_function *f, unsigned intf)
604{
605	struct f_ecm		*ecm = func_to_ecm(f);
606
607	if (intf == ecm->ctrl_id)
608		return 0;
609	return ecm->port.in_ep->enabled ? 1 : 0;
610}
611
612static void ecm_disable(struct usb_function *f)
613{
614	struct f_ecm		*ecm = func_to_ecm(f);
615	struct usb_composite_dev *cdev = f->config->cdev;
616
617	DBG(cdev, "ecm deactivated\n");
618
619	if (ecm->port.in_ep->enabled) {
620		gether_disconnect(&ecm->port);
621	} else {
622		ecm->port.in_ep->desc = NULL;
623		ecm->port.out_ep->desc = NULL;
624	}
625
626	usb_ep_disable(ecm->notify);
627	ecm->notify->desc = NULL;
628}
629
630/*-------------------------------------------------------------------------*/
631
632/*
633 * Callbacks let us notify the host about connect/disconnect when the
634 * net device is opened or closed.
635 *
636 * For testing, note that link states on this side include both opened
637 * and closed variants of:
638 *
639 *   - disconnected/unconfigured
640 *   - configured but inactive (data alt 0)
641 *   - configured and active (data alt 1)
642 *
643 * Each needs to be tested with unplug, rmmod, SET_CONFIGURATION, and
644 * SET_INTERFACE (altsetting).  Remember also that "configured" doesn't
645 * imply the host is actually polling the notification endpoint, and
646 * likewise that "active" doesn't imply it's actually using the data
647 * endpoints for traffic.
648 */
649
650static void ecm_open(struct gether *geth)
651{
652	struct f_ecm		*ecm = func_to_ecm(&geth->func);
653
654	DBG(ecm->port.func.config->cdev, "%s\n", __func__);
655
656	ecm->is_open = true;
657	ecm_notify(ecm);
658}
659
660static void ecm_close(struct gether *geth)
661{
662	struct f_ecm		*ecm = func_to_ecm(&geth->func);
663
664	DBG(ecm->port.func.config->cdev, "%s\n", __func__);
665
666	ecm->is_open = false;
667	ecm_notify(ecm);
668}
669
670/*-------------------------------------------------------------------------*/
671
672/* ethernet function driver setup/binding */
673
674static int
675ecm_bind(struct usb_configuration *c, struct usb_function *f)
676{
677	struct usb_composite_dev *cdev = c->cdev;
678	struct f_ecm		*ecm = func_to_ecm(f);
679	struct usb_string	*us;
680	int			status = 0;
681	struct usb_ep		*ep;
682
683	struct f_ecm_opts	*ecm_opts;
684	struct net_device	*net __free(detach_gadget) = NULL;
685	struct usb_request	*request __free(free_usb_request) = NULL;
686
687	if (!can_support_ecm(cdev->gadget))
688		return -EINVAL;
689
690	ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
691
692	scoped_guard(mutex, &ecm_opts->lock)
693		if (ecm_opts->bind_count == 0 && !ecm_opts->bound) {
694			if (!device_is_registered(&ecm_opts->net->dev)) {
695				gether_set_gadget(ecm_opts->net, cdev->gadget);
696				status = gether_register_netdev(ecm_opts->net);
697			} else
698				status = gether_attach_gadget(ecm_opts->net, cdev->gadget);
699
700			if (status)
701				return status;
702			net = ecm_opts->net;
703		}
704
705	ecm_string_defs[1].s = ecm->ethaddr;
706
707	us = usb_gstrings_attach(cdev, ecm_strings,
708				 ARRAY_SIZE(ecm_string_defs));
709	if (IS_ERR(us))
710		return PTR_ERR(us);
711	ecm_control_intf.iInterface = us[0].id;
712	ecm_data_intf.iInterface = us[2].id;
713	ecm_desc.iMACAddress = us[1].id;
714	ecm_iad_descriptor.iFunction = us[3].id;
715
716	/* allocate instance-specific interface IDs */
717	status = usb_interface_id(c, f);
718	if (status < 0)
719		return status;
720	ecm->ctrl_id = status;
721	ecm_iad_descriptor.bFirstInterface = status;
722
723	ecm_control_intf.bInterfaceNumber = status;
724	ecm_union_desc.bMasterInterface0 = status;
725
726	status = usb_interface_id(c, f);
727	if (status < 0)
728		return status;
729	ecm->data_id = status;
730
731	ecm_data_nop_intf.bInterfaceNumber = status;
732	ecm_data_intf.bInterfaceNumber = status;
733	ecm_union_desc.bSlaveInterface0 = status;
734
735	/* allocate instance-specific endpoints */
736	ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_in_desc);
737	if (!ep)
738		return -ENODEV;
739	ecm->port.in_ep = ep;
740
741	ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_out_desc);
742	if (!ep)
743		return -ENODEV;
744	ecm->port.out_ep = ep;
745
746	/* NOTE:  a status/notification endpoint is *OPTIONAL* but we
747	 * don't treat it that way.  It's simpler, and some newer CDC
748	 * profiles (wireless handsets) no longer treat it as optional.
749	 */
750	ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_notify_desc);
751	if (!ep)
752		return -ENODEV;
753	ecm->notify = ep;
754
755	/* allocate notification request and buffer */
756	request = usb_ep_alloc_request(ep, GFP_KERNEL);
757	if (!request)
758		return -ENOMEM;
759	request->buf = kmalloc(ECM_STATUS_BYTECOUNT, GFP_KERNEL);
760	if (!request->buf)
761		return -ENOMEM;
762	request->context = ecm;
763	request->complete = ecm_notify_complete;
764
765	/* support all relevant hardware speeds... we expect that when
766	 * hardware is dual speed, all bulk-capable endpoints work at
767	 * both speeds
768	 */
769	hs_ecm_in_desc.bEndpointAddress = fs_ecm_in_desc.bEndpointAddress;
770	hs_ecm_out_desc.bEndpointAddress = fs_ecm_out_desc.bEndpointAddress;
771	hs_ecm_notify_desc.bEndpointAddress =
772		fs_ecm_notify_desc.bEndpointAddress;
773
774	ss_ecm_in_desc.bEndpointAddress = fs_ecm_in_desc.bEndpointAddress;
775	ss_ecm_out_desc.bEndpointAddress = fs_ecm_out_desc.bEndpointAddress;
776	ss_ecm_notify_desc.bEndpointAddress =
777		fs_ecm_notify_desc.bEndpointAddress;
778
779	status = usb_assign_descriptors(f, ecm_fs_function, ecm_hs_function,
780			ecm_ss_function, ecm_ss_function);
781	if (status)
782		return status;
783
784	/* NOTE:  all that is done without knowing or caring about
785	 * the network link ... which is unavailable to this code
786	 * until we're activated via set_alt().
787	 */
788
789	ecm->port.open = ecm_open;
790	ecm->port.close = ecm_close;
791
792	ecm->notify_req = no_free_ptr(request);
793
794	ecm_opts->bind_count++;
795	retain_and_null_ptr(net);
796
797	DBG(cdev, "CDC Ethernet: IN/%s OUT/%s NOTIFY/%s\n",
798			ecm->port.in_ep->name, ecm->port.out_ep->name,
799			ecm->notify->name);
800	return 0;
801}
802
803static inline struct f_ecm_opts *to_f_ecm_opts(struct config_item *item)
804{
805	return container_of(to_config_group(item), struct f_ecm_opts,
806			    func_inst.group);
807}
808
809/* f_ecm_item_ops */
810USB_ETHERNET_CONFIGFS_ITEM(ecm);
811
812/* f_ecm_opts_dev_addr */
813USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(ecm);
814
815/* f_ecm_opts_host_addr */
816USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(ecm);
817
818/* f_ecm_opts_qmult */
819USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(ecm);
820
821/* f_ecm_opts_ifname */
822USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(ecm);
823
824static struct configfs_attribute *ecm_attrs[] = {
825	&ecm_opts_attr_dev_addr,
826	&ecm_opts_attr_host_addr,
827	&ecm_opts_attr_qmult,
828	&ecm_opts_attr_ifname,
829	NULL,
830};
831
832static const struct config_item_type ecm_func_type = {
833	.ct_item_ops	= &ecm_item_ops,
834	.ct_attrs	= ecm_attrs,
835	.ct_owner	= THIS_MODULE,
836};
837
838static void ecm_free_inst(struct usb_function_instance *f)
839{
840	struct f_ecm_opts *opts;
841
842	opts = container_of(f, struct f_ecm_opts, func_inst);
843	if (device_is_registered(&opts->net->dev))
844		gether_cleanup(netdev_priv(opts->net));
845	else
846		free_netdev(opts->net);
847	kfree(opts);
848}
849
850static struct usb_function_instance *ecm_alloc_inst(void)
851{
852	struct f_ecm_opts *opts;
853
854	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
855	if (!opts)
856		return ERR_PTR(-ENOMEM);
857	mutex_init(&opts->lock);
858	opts->func_inst.free_func_inst = ecm_free_inst;
859	opts->net = gether_setup_default();
860	if (IS_ERR(opts->net)) {
861		struct net_device *net = opts->net;
862		kfree(opts);
863		return ERR_CAST(net);
864	}
865
866	config_group_init_type_name(&opts->func_inst.group, "", &ecm_func_type);
867
868	return &opts->func_inst;
869}
870
871static void ecm_suspend(struct usb_function *f)
872{
873	struct f_ecm *ecm = func_to_ecm(f);
874	struct usb_composite_dev *cdev = ecm->port.func.config->cdev;
875
876	DBG(cdev, "ECM Suspend\n");
877
878	gether_suspend(&ecm->port);
879}
880
881static void ecm_resume(struct usb_function *f)
882{
883	struct f_ecm *ecm = func_to_ecm(f);
884	struct usb_composite_dev *cdev = ecm->port.func.config->cdev;
885
886	DBG(cdev, "ECM Resume\n");
887
888	gether_resume(&ecm->port);
889}
890
891static int ecm_get_status(struct usb_function *f)
892{
893	return (f->func_wakeup_armed ? USB_INTRF_STAT_FUNC_RW : 0) |
894		USB_INTRF_STAT_FUNC_RW_CAP;
895}
896
897static void ecm_free(struct usb_function *f)
898{
899	struct f_ecm *ecm;
900	struct f_ecm_opts *opts;
901
902	ecm = func_to_ecm(f);
903	opts = container_of(f->fi, struct f_ecm_opts, func_inst);
904	kfree(ecm);
905	mutex_lock(&opts->lock);
906	opts->refcnt--;
907	mutex_unlock(&opts->lock);
908}
909
910static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
911{
912	struct f_ecm		*ecm = func_to_ecm(f);
913	struct f_ecm_opts	*ecm_opts;
914
915	DBG(c->cdev, "ecm unbind\n");
916
917	ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
918
919	usb_free_all_descriptors(f);
920
921	if (atomic_read(&ecm->notify_count)) {
922		usb_ep_dequeue(ecm->notify, ecm->notify_req);
923		atomic_set(&ecm->notify_count, 0);
924	}
925
926	kfree(ecm->notify_req->buf);
927	usb_ep_free_request(ecm->notify, ecm->notify_req);
928
929	ecm_opts->bind_count--;
930	if (ecm_opts->bind_count == 0 && !ecm_opts->bound)
931		gether_detach_gadget(ecm_opts->net);
932}
933
934static struct usb_function *ecm_alloc(struct usb_function_instance *fi)
935{
936	struct f_ecm	*ecm;
937	struct f_ecm_opts *opts;
938	int status;
939
940	/* allocate and initialize one new instance */
941	ecm = kzalloc(sizeof(*ecm), GFP_KERNEL);
942	if (!ecm)
943		return ERR_PTR(-ENOMEM);
944
945	opts = container_of(fi, struct f_ecm_opts, func_inst);
946	mutex_lock(&opts->lock);
947	opts->refcnt++;
948
949	/* export host's Ethernet address in CDC format */
950	status = gether_get_host_addr_cdc(opts->net, ecm->ethaddr,
951					  sizeof(ecm->ethaddr));
952	if (status < 12) {
953		kfree(ecm);
954		mutex_unlock(&opts->lock);
955		return ERR_PTR(-EINVAL);
956	}
957
958	ecm->port.ioport = netdev_priv(opts->net);
959	mutex_unlock(&opts->lock);
960	ecm->port.cdc_filter = DEFAULT_FILTER;
961
962	ecm->port.func.name = "cdc_ethernet";
963	/* descriptors are per-instance copies */
964	ecm->port.func.bind = ecm_bind;
965	ecm->port.func.unbind = ecm_unbind;
966	ecm->port.func.set_alt = ecm_set_alt;
967	ecm->port.func.get_alt = ecm_get_alt;
968	ecm->port.func.setup = ecm_setup;
969	ecm->port.func.disable = ecm_disable;
970	ecm->port.func.free_func = ecm_free;
971	ecm->port.func.suspend = ecm_suspend;
972	ecm->port.func.get_status = ecm_get_status;
973	ecm->port.func.resume = ecm_resume;
974
975	return &ecm->port.func;
976}
977
978DECLARE_USB_FUNCTION_INIT(ecm, ecm_alloc_inst, ecm_alloc);
979MODULE_DESCRIPTION("USB CDC Ethernet (ECM) link function driver");
980MODULE_LICENSE("GPL");
981MODULE_AUTHOR("David Brownell");