1 /*
2  * u_ether.c -- Ethernet-over-USB link layer utilities for Gadget stack
3  *
4  * Copyright (C) 2003-2005,2008 David Brownell
5  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
6  * Copyright (C) 2008 Nokia Corporation
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  */
13 
14 /* #define VERBOSE_DEBUG */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/gfp.h>
19 #include <linux/device.h>
20 #include <linux/ctype.h>
21 #include <linux/etherdevice.h>
22 #include <linux/ethtool.h>
23 #include <linux/if_vlan.h>
24 
25 #include "u_ether.h"
26 
27 
28 /*
29  * This component encapsulates the Ethernet link glue needed to provide
30  * one (!) network link through the USB gadget stack, normally "usb0".
31  *
32  * The control and data models are handled by the function driver which
33  * connects to this code; such as CDC Ethernet (ECM or EEM),
34  * "CDC Subset", or RNDIS.  That includes all descriptor and endpoint
35  * management.
36  *
37  * Link level addressing is handled by this component using module
38  * parameters; if no such parameters are provided, random link level
39  * addresses are used.  Each end of the link uses one address.  The
40  * host end address is exported in various ways, and is often recorded
41  * in configuration databases.
42  *
43  * The driver which assembles each configuration using such a link is
44  * responsible for ensuring that each configuration includes at most one
45  * instance of is network link.  (The network layer provides ways for
46  * this single "physical" link to be used by multiple virtual links.)
47  */
48 
49 #define UETH__VERSION	"29-May-2008"
50 
51 struct eth_dev {
52 	/* lock is held while accessing port_usb
53 	 */
54 	spinlock_t		lock;
55 	struct gether		*port_usb;
56 
57 	struct net_device	*net;
58 	struct usb_gadget	*gadget;
59 
60 	spinlock_t		req_lock;	/* guard {rx,tx}_reqs */
61 	struct list_head	tx_reqs, rx_reqs;
62 	atomic_t		tx_qlen;
63 
64 	struct sk_buff_head	rx_frames;
65 
66 	unsigned		qmult;
67 
68 	unsigned		header_len;
69 	struct sk_buff		*(*wrap)(struct gether *, struct sk_buff *skb);
70 	int			(*unwrap)(struct gether *,
71 						struct sk_buff *skb,
72 						struct sk_buff_head *list);
73 
74 	struct work_struct	work;
75 
76 	unsigned long		todo;
77 #define	WORK_RX_MEMORY		0
78 
79 	bool			zlp;
80 	u8			host_mac[ETH_ALEN];
81 	u8			dev_mac[ETH_ALEN];
82 };
83 
84 /*-------------------------------------------------------------------------*/
85 
86 #define RX_EXTRA	20	/* bytes guarding against rx overflows */
87 
88 #define DEFAULT_QLEN	2	/* double buffering by default */
89 
90 /* for dual-speed hardware, use deeper queues at high/super speed */
91 static inline int qlen(struct usb_gadget *gadget, unsigned qmult)
92 {
93 	if (gadget_is_dualspeed(gadget) && (gadget->speed == USB_SPEED_HIGH ||
94 					    gadget->speed == USB_SPEED_SUPER))
95 		return qmult * DEFAULT_QLEN;
96 	else
97 		return DEFAULT_QLEN;
98 }
99 
100 /*-------------------------------------------------------------------------*/
101 
102 /* REVISIT there must be a better way than having two sets
103  * of debug calls ...
104  */
105 
106 #undef DBG
107 #undef VDBG
108 #undef ERROR
109 #undef INFO
110 
111 #define xprintk(d, level, fmt, args...) \
112 	printk(level "%s: " fmt , (d)->net->name , ## args)
113 
114 #ifdef DEBUG
115 #undef DEBUG
116 #define DBG(dev, fmt, args...) \
117 	xprintk(dev , KERN_DEBUG , fmt , ## args)
118 #else
119 #define DBG(dev, fmt, args...) \
120 	do { } while (0)
121 #endif /* DEBUG */
122 
123 #ifdef VERBOSE_DEBUG
124 #define VDBG	DBG
125 #else
126 #define VDBG(dev, fmt, args...) \
127 	do { } while (0)
128 #endif /* DEBUG */
129 
130 #define ERROR(dev, fmt, args...) \
131 	xprintk(dev , KERN_ERR , fmt , ## args)
132 #define INFO(dev, fmt, args...) \
133 	xprintk(dev , KERN_INFO , fmt , ## args)
134 
135 /*-------------------------------------------------------------------------*/
136 
137 /* NETWORK DRIVER HOOKUP (to the layer above this driver) */
138 
139 static int ueth_change_mtu(struct net_device *net, int new_mtu)
140 {
141 	struct eth_dev	*dev = netdev_priv(net);
142 	unsigned long	flags;
143 	int		status = 0;
144 
145 	/* don't change MTU on "live" link (peer won't know) */
146 	spin_lock_irqsave(&dev->lock, flags);
147 	if (dev->port_usb)
148 		status = -EBUSY;
149 	else if (new_mtu <= ETH_HLEN || new_mtu > ETH_FRAME_LEN)
150 		status = -ERANGE;
151 	else
152 		net->mtu = new_mtu;
153 	spin_unlock_irqrestore(&dev->lock, flags);
154 
155 	return status;
156 }
157 
158 static void eth_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *p)
159 {
160 	struct eth_dev *dev = netdev_priv(net);
161 
162 	strlcpy(p->driver, "g_ether", sizeof(p->driver));
163 	strlcpy(p->version, UETH__VERSION, sizeof(p->version));
164 	strlcpy(p->fw_version, dev->gadget->name, sizeof(p->fw_version));
165 	strlcpy(p->bus_info, dev_name(&dev->gadget->dev), sizeof(p->bus_info));
166 }
167 
168 /* REVISIT can also support:
169  *   - WOL (by tracking suspends and issuing remote wakeup)
170  *   - msglevel (implies updated messaging)
171  *   - ... probably more ethtool ops
172  */
173 
174 static const struct ethtool_ops ops = {
175 	.get_drvinfo = eth_get_drvinfo,
176 	.get_link = ethtool_op_get_link,
177 };
178 
179 static void defer_kevent(struct eth_dev *dev, int flag)
180 {
181 	if (test_and_set_bit(flag, &dev->todo))
182 		return;
183 	if (!schedule_work(&dev->work))
184 		ERROR(dev, "kevent %d may have been dropped\n", flag);
185 	else
186 		DBG(dev, "kevent %d scheduled\n", flag);
187 }
188 
189 static void rx_complete(struct usb_ep *ep, struct usb_request *req);
190 
191 static int
192 rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
193 {
194 	struct sk_buff	*skb;
195 	int		retval = -ENOMEM;
196 	size_t		size = 0;
197 	struct usb_ep	*out;
198 	unsigned long	flags;
199 
200 	spin_lock_irqsave(&dev->lock, flags);
201 	if (dev->port_usb)
202 		out = dev->port_usb->out_ep;
203 	else
204 		out = NULL;
205 	spin_unlock_irqrestore(&dev->lock, flags);
206 
207 	if (!out)
208 		return -ENOTCONN;
209 
210 
211 	/* Padding up to RX_EXTRA handles minor disagreements with host.
212 	 * Normally we use the USB "terminate on short read" convention;
213 	 * so allow up to (N*maxpacket), since that memory is normally
214 	 * already allocated.  Some hardware doesn't deal well with short
215 	 * reads (e.g. DMA must be N*maxpacket), so for now don't trim a
216 	 * byte off the end (to force hardware errors on overflow).
217 	 *
218 	 * RNDIS uses internal framing, and explicitly allows senders to
219 	 * pad to end-of-packet.  That's potentially nice for speed, but
220 	 * means receivers can't recover lost synch on their own (because
221 	 * new packets don't only start after a short RX).
222 	 */
223 	size += sizeof(struct ethhdr) + dev->net->mtu + RX_EXTRA;
224 	size += dev->port_usb->header_len;
225 	size += out->maxpacket - 1;
226 	size -= size % out->maxpacket;
227 
228 	if (dev->port_usb->is_fixed)
229 		size = max_t(size_t, size, dev->port_usb->fixed_out_len);
230 
231 	skb = alloc_skb(size + NET_IP_ALIGN, gfp_flags);
232 	if (skb == NULL) {
233 		DBG(dev, "no rx skb\n");
234 		goto enomem;
235 	}
236 
237 	/* Some platforms perform better when IP packets are aligned,
238 	 * but on at least one, checksumming fails otherwise.  Note:
239 	 * RNDIS headers involve variable numbers of LE32 values.
240 	 */
241 	skb_reserve(skb, NET_IP_ALIGN);
242 
243 	req->buf = skb->data;
244 	req->length = size;
245 	req->complete = rx_complete;
246 	req->context = skb;
247 
248 	retval = usb_ep_queue(out, req, gfp_flags);
249 	if (retval == -ENOMEM)
250 enomem:
251 		defer_kevent(dev, WORK_RX_MEMORY);
252 	if (retval) {
253 		DBG(dev, "rx submit --> %d\n", retval);
254 		if (skb)
255 			dev_kfree_skb_any(skb);
256 		spin_lock_irqsave(&dev->req_lock, flags);
257 		list_add(&req->list, &dev->rx_reqs);
258 		spin_unlock_irqrestore(&dev->req_lock, flags);
259 	}
260 	return retval;
261 }
262 
263 static void rx_complete(struct usb_ep *ep, struct usb_request *req)
264 {
265 	struct sk_buff	*skb = req->context, *skb2;
266 	struct eth_dev	*dev = ep->driver_data;
267 	int		status = req->status;
268 
269 	switch (status) {
270 
271 	/* normal completion */
272 	case 0:
273 		skb_put(skb, req->actual);
274 
275 		if (dev->unwrap) {
276 			unsigned long	flags;
277 
278 			spin_lock_irqsave(&dev->lock, flags);
279 			if (dev->port_usb) {
280 				status = dev->unwrap(dev->port_usb,
281 							skb,
282 							&dev->rx_frames);
283 			} else {
284 				dev_kfree_skb_any(skb);
285 				status = -ENOTCONN;
286 			}
287 			spin_unlock_irqrestore(&dev->lock, flags);
288 		} else {
289 			skb_queue_tail(&dev->rx_frames, skb);
290 		}
291 		skb = NULL;
292 
293 		skb2 = skb_dequeue(&dev->rx_frames);
294 		while (skb2) {
295 			if (status < 0
296 					|| ETH_HLEN > skb2->len
297 					|| skb2->len > VLAN_ETH_FRAME_LEN) {
298 				dev->net->stats.rx_errors++;
299 				dev->net->stats.rx_length_errors++;
300 				DBG(dev, "rx length %d\n", skb2->len);
301 				dev_kfree_skb_any(skb2);
302 				goto next_frame;
303 			}
304 			skb2->protocol = eth_type_trans(skb2, dev->net);
305 			dev->net->stats.rx_packets++;
306 			dev->net->stats.rx_bytes += skb2->len;
307 
308 			/* no buffer copies needed, unless hardware can't
309 			 * use skb buffers.
310 			 */
311 			status = netif_rx(skb2);
312 next_frame:
313 			skb2 = skb_dequeue(&dev->rx_frames);
314 		}
315 		break;
316 
317 	/* software-driven interface shutdown */
318 	case -ECONNRESET:		/* unlink */
319 	case -ESHUTDOWN:		/* disconnect etc */
320 		VDBG(dev, "rx shutdown, code %d\n", status);
321 		goto quiesce;
322 
323 	/* for hardware automagic (such as pxa) */
324 	case -ECONNABORTED:		/* endpoint reset */
325 		DBG(dev, "rx %s reset\n", ep->name);
326 		defer_kevent(dev, WORK_RX_MEMORY);
327 quiesce:
328 		dev_kfree_skb_any(skb);
329 		goto clean;
330 
331 	/* data overrun */
332 	case -EOVERFLOW:
333 		dev->net->stats.rx_over_errors++;
334 		/* FALLTHROUGH */
335 
336 	default:
337 		dev->net->stats.rx_errors++;
338 		DBG(dev, "rx status %d\n", status);
339 		break;
340 	}
341 
342 	if (skb)
343 		dev_kfree_skb_any(skb);
344 	if (!netif_running(dev->net)) {
345 clean:
346 		spin_lock(&dev->req_lock);
347 		list_add(&req->list, &dev->rx_reqs);
348 		spin_unlock(&dev->req_lock);
349 		req = NULL;
350 	}
351 	if (req)
352 		rx_submit(dev, req, GFP_ATOMIC);
353 }
354 
355 static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
356 {
357 	unsigned		i;
358 	struct usb_request	*req;
359 
360 	if (!n)
361 		return -ENOMEM;
362 
363 	/* queue/recycle up to N requests */
364 	i = n;
365 	list_for_each_entry(req, list, list) {
366 		if (i-- == 0)
367 			goto extra;
368 	}
369 	while (i--) {
370 		req = usb_ep_alloc_request(ep, GFP_ATOMIC);
371 		if (!req)
372 			return list_empty(list) ? -ENOMEM : 0;
373 		list_add(&req->list, list);
374 	}
375 	return 0;
376 
377 extra:
378 	/* free extras */
379 	for (;;) {
380 		struct list_head	*next;
381 
382 		next = req->list.next;
383 		list_del(&req->list);
384 		usb_ep_free_request(ep, req);
385 
386 		if (next == list)
387 			break;
388 
389 		req = container_of(next, struct usb_request, list);
390 	}
391 	return 0;
392 }
393 
394 static int alloc_requests(struct eth_dev *dev, struct gether *link, unsigned n)
395 {
396 	int	status;
397 
398 	spin_lock(&dev->req_lock);
399 	status = prealloc(&dev->tx_reqs, link->in_ep, n);
400 	if (status < 0)
401 		goto fail;
402 	status = prealloc(&dev->rx_reqs, link->out_ep, n);
403 	if (status < 0)
404 		goto fail;
405 	goto done;
406 fail:
407 	DBG(dev, "can't alloc requests\n");
408 done:
409 	spin_unlock(&dev->req_lock);
410 	return status;
411 }
412 
413 static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
414 {
415 	struct usb_request	*req;
416 	unsigned long		flags;
417 
418 	/* fill unused rxq slots with some skb */
419 	spin_lock_irqsave(&dev->req_lock, flags);
420 	while (!list_empty(&dev->rx_reqs)) {
421 		req = container_of(dev->rx_reqs.next,
422 				struct usb_request, list);
423 		list_del_init(&req->list);
424 		spin_unlock_irqrestore(&dev->req_lock, flags);
425 
426 		if (rx_submit(dev, req, gfp_flags) < 0) {
427 			defer_kevent(dev, WORK_RX_MEMORY);
428 			return;
429 		}
430 
431 		spin_lock_irqsave(&dev->req_lock, flags);
432 	}
433 	spin_unlock_irqrestore(&dev->req_lock, flags);
434 }
435 
436 static void eth_work(struct work_struct *work)
437 {
438 	struct eth_dev	*dev = container_of(work, struct eth_dev, work);
439 
440 	if (test_and_clear_bit(WORK_RX_MEMORY, &dev->todo)) {
441 		if (netif_running(dev->net))
442 			rx_fill(dev, GFP_KERNEL);
443 	}
444 
445 	if (dev->todo)
446 		DBG(dev, "work done, flags = 0x%lx\n", dev->todo);
447 }
448 
449 static void tx_complete(struct usb_ep *ep, struct usb_request *req)
450 {
451 	struct sk_buff	*skb = req->context;
452 	struct eth_dev	*dev = ep->driver_data;
453 
454 	switch (req->status) {
455 	default:
456 		dev->net->stats.tx_errors++;
457 		VDBG(dev, "tx err %d\n", req->status);
458 		/* FALLTHROUGH */
459 	case -ECONNRESET:		/* unlink */
460 	case -ESHUTDOWN:		/* disconnect etc */
461 		break;
462 	case 0:
463 		dev->net->stats.tx_bytes += skb->len;
464 	}
465 	dev->net->stats.tx_packets++;
466 
467 	spin_lock(&dev->req_lock);
468 	list_add(&req->list, &dev->tx_reqs);
469 	spin_unlock(&dev->req_lock);
470 	dev_kfree_skb_any(skb);
471 
472 	atomic_dec(&dev->tx_qlen);
473 	if (netif_carrier_ok(dev->net))
474 		netif_wake_queue(dev->net);
475 }
476 
477 static inline int is_promisc(u16 cdc_filter)
478 {
479 	return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
480 }
481 
482 static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
483 					struct net_device *net)
484 {
485 	struct eth_dev		*dev = netdev_priv(net);
486 	int			length = 0;
487 	int			retval;
488 	struct usb_request	*req = NULL;
489 	unsigned long		flags;
490 	struct usb_ep		*in;
491 	u16			cdc_filter;
492 
493 	spin_lock_irqsave(&dev->lock, flags);
494 	if (dev->port_usb) {
495 		in = dev->port_usb->in_ep;
496 		cdc_filter = dev->port_usb->cdc_filter;
497 	} else {
498 		in = NULL;
499 		cdc_filter = 0;
500 	}
501 	spin_unlock_irqrestore(&dev->lock, flags);
502 
503 	if (skb && !in) {
504 		dev_kfree_skb_any(skb);
505 		return NETDEV_TX_OK;
506 	}
507 
508 	/* apply outgoing CDC or RNDIS filters */
509 	if (skb && !is_promisc(cdc_filter)) {
510 		u8		*dest = skb->data;
511 
512 		if (is_multicast_ether_addr(dest)) {
513 			u16	type;
514 
515 			/* ignores USB_CDC_PACKET_TYPE_MULTICAST and host
516 			 * SET_ETHERNET_MULTICAST_FILTERS requests
517 			 */
518 			if (is_broadcast_ether_addr(dest))
519 				type = USB_CDC_PACKET_TYPE_BROADCAST;
520 			else
521 				type = USB_CDC_PACKET_TYPE_ALL_MULTICAST;
522 			if (!(cdc_filter & type)) {
523 				dev_kfree_skb_any(skb);
524 				return NETDEV_TX_OK;
525 			}
526 		}
527 		/* ignores USB_CDC_PACKET_TYPE_DIRECTED */
528 	}
529 
530 	spin_lock_irqsave(&dev->req_lock, flags);
531 	/*
532 	 * this freelist can be empty if an interrupt triggered disconnect()
533 	 * and reconfigured the gadget (shutting down this queue) after the
534 	 * network stack decided to xmit but before we got the spinlock.
535 	 */
536 	if (list_empty(&dev->tx_reqs)) {
537 		spin_unlock_irqrestore(&dev->req_lock, flags);
538 		return NETDEV_TX_BUSY;
539 	}
540 
541 	req = container_of(dev->tx_reqs.next, struct usb_request, list);
542 	list_del(&req->list);
543 
544 	/* temporarily stop TX queue when the freelist empties */
545 	if (list_empty(&dev->tx_reqs))
546 		netif_stop_queue(net);
547 	spin_unlock_irqrestore(&dev->req_lock, flags);
548 
549 	/* no buffer copies needed, unless the network stack did it
550 	 * or the hardware can't use skb buffers.
551 	 * or there's not enough space for extra headers we need
552 	 */
553 	if (dev->wrap) {
554 		unsigned long	flags;
555 
556 		spin_lock_irqsave(&dev->lock, flags);
557 		if (dev->port_usb)
558 			skb = dev->wrap(dev->port_usb, skb);
559 		spin_unlock_irqrestore(&dev->lock, flags);
560 		if (!skb) {
561 			/* Multi frame CDC protocols may store the frame for
562 			 * later which is not a dropped frame.
563 			 */
564 			if (dev->port_usb->supports_multi_frame)
565 				goto multiframe;
566 			goto drop;
567 		}
568 	}
569 
570 	length = skb->len;
571 	req->buf = skb->data;
572 	req->context = skb;
573 	req->complete = tx_complete;
574 
575 	/* NCM requires no zlp if transfer is dwNtbInMaxSize */
576 	if (dev->port_usb->is_fixed &&
577 	    length == dev->port_usb->fixed_in_len &&
578 	    (length % in->maxpacket) == 0)
579 		req->zero = 0;
580 	else
581 		req->zero = 1;
582 
583 	/* use zlp framing on tx for strict CDC-Ether conformance,
584 	 * though any robust network rx path ignores extra padding.
585 	 * and some hardware doesn't like to write zlps.
586 	 */
587 	if (req->zero && !dev->zlp && (length % in->maxpacket) == 0)
588 		length++;
589 
590 	req->length = length;
591 
592 	/* throttle high/super speed IRQ rate back slightly */
593 	if (gadget_is_dualspeed(dev->gadget))
594 		req->no_interrupt = (dev->gadget->speed == USB_SPEED_HIGH ||
595 				     dev->gadget->speed == USB_SPEED_SUPER)
596 			? ((atomic_read(&dev->tx_qlen) % dev->qmult) != 0)
597 			: 0;
598 
599 	retval = usb_ep_queue(in, req, GFP_ATOMIC);
600 	switch (retval) {
601 	default:
602 		DBG(dev, "tx queue err %d\n", retval);
603 		break;
604 	case 0:
605 		net->trans_start = jiffies;
606 		atomic_inc(&dev->tx_qlen);
607 	}
608 
609 	if (retval) {
610 		dev_kfree_skb_any(skb);
611 drop:
612 		dev->net->stats.tx_dropped++;
613 multiframe:
614 		spin_lock_irqsave(&dev->req_lock, flags);
615 		if (list_empty(&dev->tx_reqs))
616 			netif_start_queue(net);
617 		list_add(&req->list, &dev->tx_reqs);
618 		spin_unlock_irqrestore(&dev->req_lock, flags);
619 	}
620 	return NETDEV_TX_OK;
621 }
622 
623 /*-------------------------------------------------------------------------*/
624 
625 static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
626 {
627 	DBG(dev, "%s\n", __func__);
628 
629 	/* fill the rx queue */
630 	rx_fill(dev, gfp_flags);
631 
632 	/* and open the tx floodgates */
633 	atomic_set(&dev->tx_qlen, 0);
634 	netif_wake_queue(dev->net);
635 }
636 
637 static int eth_open(struct net_device *net)
638 {
639 	struct eth_dev	*dev = netdev_priv(net);
640 	struct gether	*link;
641 
642 	DBG(dev, "%s\n", __func__);
643 	if (netif_carrier_ok(dev->net))
644 		eth_start(dev, GFP_KERNEL);
645 
646 	spin_lock_irq(&dev->lock);
647 	link = dev->port_usb;
648 	if (link && link->open)
649 		link->open(link);
650 	spin_unlock_irq(&dev->lock);
651 
652 	return 0;
653 }
654 
655 static int eth_stop(struct net_device *net)
656 {
657 	struct eth_dev	*dev = netdev_priv(net);
658 	unsigned long	flags;
659 
660 	VDBG(dev, "%s\n", __func__);
661 	netif_stop_queue(net);
662 
663 	DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
664 		dev->net->stats.rx_packets, dev->net->stats.tx_packets,
665 		dev->net->stats.rx_errors, dev->net->stats.tx_errors
666 		);
667 
668 	/* ensure there are no more active requests */
669 	spin_lock_irqsave(&dev->lock, flags);
670 	if (dev->port_usb) {
671 		struct gether	*link = dev->port_usb;
672 		const struct usb_endpoint_descriptor *in;
673 		const struct usb_endpoint_descriptor *out;
674 
675 		if (link->close)
676 			link->close(link);
677 
678 		/* NOTE:  we have no abort-queue primitive we could use
679 		 * to cancel all pending I/O.  Instead, we disable then
680 		 * reenable the endpoints ... this idiom may leave toggle
681 		 * wrong, but that's a self-correcting error.
682 		 *
683 		 * REVISIT:  we *COULD* just let the transfers complete at
684 		 * their own pace; the network stack can handle old packets.
685 		 * For the moment we leave this here, since it works.
686 		 */
687 		in = link->in_ep->desc;
688 		out = link->out_ep->desc;
689 		usb_ep_disable(link->in_ep);
690 		usb_ep_disable(link->out_ep);
691 		if (netif_carrier_ok(net)) {
692 			DBG(dev, "host still using in/out endpoints\n");
693 			link->in_ep->desc = in;
694 			link->out_ep->desc = out;
695 			usb_ep_enable(link->in_ep);
696 			usb_ep_enable(link->out_ep);
697 		}
698 	}
699 	spin_unlock_irqrestore(&dev->lock, flags);
700 
701 	return 0;
702 }
703 
704 /*-------------------------------------------------------------------------*/
705 
706 static int get_ether_addr(const char *str, u8 *dev_addr)
707 {
708 	if (str) {
709 		unsigned	i;
710 
711 		for (i = 0; i < 6; i++) {
712 			unsigned char num;
713 
714 			if ((*str == '.') || (*str == ':'))
715 				str++;
716 			num = hex_to_bin(*str++) << 4;
717 			num |= hex_to_bin(*str++);
718 			dev_addr [i] = num;
719 		}
720 		if (is_valid_ether_addr(dev_addr))
721 			return 0;
722 	}
723 	eth_random_addr(dev_addr);
724 	return 1;
725 }
726 
727 static int get_ether_addr_str(u8 dev_addr[ETH_ALEN], char *str, int len)
728 {
729 	if (len < 18)
730 		return -EINVAL;
731 
732 	snprintf(str, len, "%pM", dev_addr);
733 	return 18;
734 }
735 
736 static const struct net_device_ops eth_netdev_ops = {
737 	.ndo_open		= eth_open,
738 	.ndo_stop		= eth_stop,
739 	.ndo_start_xmit		= eth_start_xmit,
740 	.ndo_change_mtu		= ueth_change_mtu,
741 	.ndo_set_mac_address 	= eth_mac_addr,
742 	.ndo_validate_addr	= eth_validate_addr,
743 };
744 
745 static struct device_type gadget_type = {
746 	.name	= "gadget",
747 };
748 
749 /**
750  * gether_setup_name - initialize one ethernet-over-usb link
751  * @g: gadget to associated with these links
752  * @ethaddr: NULL, or a buffer in which the ethernet address of the
753  *	host side of the link is recorded
754  * @netname: name for network device (for example, "usb")
755  * Context: may sleep
756  *
757  * This sets up the single network link that may be exported by a
758  * gadget driver using this framework.  The link layer addresses are
759  * set up using module parameters.
760  *
761  * Returns an eth_dev pointer on success, or an ERR_PTR on failure.
762  */
763 struct eth_dev *gether_setup_name(struct usb_gadget *g,
764 		const char *dev_addr, const char *host_addr,
765 		u8 ethaddr[ETH_ALEN], unsigned qmult, const char *netname)
766 {
767 	struct eth_dev		*dev;
768 	struct net_device	*net;
769 	int			status;
770 
771 	net = alloc_etherdev(sizeof *dev);
772 	if (!net)
773 		return ERR_PTR(-ENOMEM);
774 
775 	dev = netdev_priv(net);
776 	spin_lock_init(&dev->lock);
777 	spin_lock_init(&dev->req_lock);
778 	INIT_WORK(&dev->work, eth_work);
779 	INIT_LIST_HEAD(&dev->tx_reqs);
780 	INIT_LIST_HEAD(&dev->rx_reqs);
781 
782 	skb_queue_head_init(&dev->rx_frames);
783 
784 	/* network device setup */
785 	dev->net = net;
786 	dev->qmult = qmult;
787 	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
788 
789 	if (get_ether_addr(dev_addr, net->dev_addr))
790 		dev_warn(&g->dev,
791 			"using random %s ethernet address\n", "self");
792 	if (get_ether_addr(host_addr, dev->host_mac))
793 		dev_warn(&g->dev,
794 			"using random %s ethernet address\n", "host");
795 
796 	if (ethaddr)
797 		memcpy(ethaddr, dev->host_mac, ETH_ALEN);
798 
799 	net->netdev_ops = &eth_netdev_ops;
800 
801 	net->ethtool_ops = &ops;
802 
803 	dev->gadget = g;
804 	SET_NETDEV_DEV(net, &g->dev);
805 	SET_NETDEV_DEVTYPE(net, &gadget_type);
806 
807 	status = register_netdev(net);
808 	if (status < 0) {
809 		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
810 		free_netdev(net);
811 		dev = ERR_PTR(status);
812 	} else {
813 		INFO(dev, "MAC %pM\n", net->dev_addr);
814 		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
815 
816 		/*
817 		 * two kinds of host-initiated state changes:
818 		 *  - iff DATA transfer is active, carrier is "on"
819 		 *  - tx queueing enabled if open *and* carrier is "on"
820 		 */
821 		netif_carrier_off(net);
822 	}
823 
824 	return dev;
825 }
826 EXPORT_SYMBOL_GPL(gether_setup_name);
827 
828 struct net_device *gether_setup_name_default(const char *netname)
829 {
830 	struct net_device	*net;
831 	struct eth_dev		*dev;
832 
833 	net = alloc_etherdev(sizeof(*dev));
834 	if (!net)
835 		return ERR_PTR(-ENOMEM);
836 
837 	dev = netdev_priv(net);
838 	spin_lock_init(&dev->lock);
839 	spin_lock_init(&dev->req_lock);
840 	INIT_WORK(&dev->work, eth_work);
841 	INIT_LIST_HEAD(&dev->tx_reqs);
842 	INIT_LIST_HEAD(&dev->rx_reqs);
843 
844 	skb_queue_head_init(&dev->rx_frames);
845 
846 	/* network device setup */
847 	dev->net = net;
848 	dev->qmult = QMULT_DEFAULT;
849 	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
850 
851 	eth_random_addr(dev->dev_mac);
852 	pr_warn("using random %s ethernet address\n", "self");
853 	eth_random_addr(dev->host_mac);
854 	pr_warn("using random %s ethernet address\n", "host");
855 
856 	net->netdev_ops = &eth_netdev_ops;
857 
858 	net->ethtool_ops = &ops;
859 	SET_NETDEV_DEVTYPE(net, &gadget_type);
860 
861 	return net;
862 }
863 EXPORT_SYMBOL_GPL(gether_setup_name_default);
864 
865 int gether_register_netdev(struct net_device *net)
866 {
867 	struct eth_dev *dev;
868 	struct usb_gadget *g;
869 	struct sockaddr sa;
870 	int status;
871 
872 	if (!net->dev.parent)
873 		return -EINVAL;
874 	dev = netdev_priv(net);
875 	g = dev->gadget;
876 	status = register_netdev(net);
877 	if (status < 0) {
878 		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
879 		return status;
880 	} else {
881 		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
882 
883 		/* two kinds of host-initiated state changes:
884 		 *  - iff DATA transfer is active, carrier is "on"
885 		 *  - tx queueing enabled if open *and* carrier is "on"
886 		 */
887 		netif_carrier_off(net);
888 	}
889 	sa.sa_family = net->type;
890 	memcpy(sa.sa_data, dev->dev_mac, ETH_ALEN);
891 	rtnl_lock();
892 	status = dev_set_mac_address(net, &sa);
893 	rtnl_unlock();
894 	if (status)
895 		pr_warn("cannot set self ethernet address: %d\n", status);
896 	else
897 		INFO(dev, "MAC %pM\n", dev->dev_mac);
898 
899 	return status;
900 }
901 EXPORT_SYMBOL_GPL(gether_register_netdev);
902 
903 void gether_set_gadget(struct net_device *net, struct usb_gadget *g)
904 {
905 	struct eth_dev *dev;
906 
907 	dev = netdev_priv(net);
908 	dev->gadget = g;
909 	SET_NETDEV_DEV(net, &g->dev);
910 }
911 EXPORT_SYMBOL_GPL(gether_set_gadget);
912 
913 int gether_set_dev_addr(struct net_device *net, const char *dev_addr)
914 {
915 	struct eth_dev *dev;
916 	u8 new_addr[ETH_ALEN];
917 
918 	dev = netdev_priv(net);
919 	if (get_ether_addr(dev_addr, new_addr))
920 		return -EINVAL;
921 	memcpy(dev->dev_mac, new_addr, ETH_ALEN);
922 	return 0;
923 }
924 EXPORT_SYMBOL_GPL(gether_set_dev_addr);
925 
926 int gether_get_dev_addr(struct net_device *net, char *dev_addr, int len)
927 {
928 	struct eth_dev *dev;
929 
930 	dev = netdev_priv(net);
931 	return get_ether_addr_str(dev->dev_mac, dev_addr, len);
932 }
933 EXPORT_SYMBOL_GPL(gether_get_dev_addr);
934 
935 int gether_set_host_addr(struct net_device *net, const char *host_addr)
936 {
937 	struct eth_dev *dev;
938 	u8 new_addr[ETH_ALEN];
939 
940 	dev = netdev_priv(net);
941 	if (get_ether_addr(host_addr, new_addr))
942 		return -EINVAL;
943 	memcpy(dev->host_mac, new_addr, ETH_ALEN);
944 	return 0;
945 }
946 EXPORT_SYMBOL_GPL(gether_set_host_addr);
947 
948 int gether_get_host_addr(struct net_device *net, char *host_addr, int len)
949 {
950 	struct eth_dev *dev;
951 
952 	dev = netdev_priv(net);
953 	return get_ether_addr_str(dev->host_mac, host_addr, len);
954 }
955 EXPORT_SYMBOL_GPL(gether_get_host_addr);
956 
957 int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
958 {
959 	struct eth_dev *dev;
960 
961 	if (len < 13)
962 		return -EINVAL;
963 
964 	dev = netdev_priv(net);
965 	snprintf(host_addr, len, "%pm", dev->host_mac);
966 
967 	return strlen(host_addr);
968 }
969 EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
970 
971 void gether_get_host_addr_u8(struct net_device *net, u8 host_mac[ETH_ALEN])
972 {
973 	struct eth_dev *dev;
974 
975 	dev = netdev_priv(net);
976 	memcpy(host_mac, dev->host_mac, ETH_ALEN);
977 }
978 EXPORT_SYMBOL_GPL(gether_get_host_addr_u8);
979 
980 void gether_set_qmult(struct net_device *net, unsigned qmult)
981 {
982 	struct eth_dev *dev;
983 
984 	dev = netdev_priv(net);
985 	dev->qmult = qmult;
986 }
987 EXPORT_SYMBOL_GPL(gether_set_qmult);
988 
989 unsigned gether_get_qmult(struct net_device *net)
990 {
991 	struct eth_dev *dev;
992 
993 	dev = netdev_priv(net);
994 	return dev->qmult;
995 }
996 EXPORT_SYMBOL_GPL(gether_get_qmult);
997 
998 int gether_get_ifname(struct net_device *net, char *name, int len)
999 {
1000 	rtnl_lock();
1001 	strlcpy(name, netdev_name(net), len);
1002 	rtnl_unlock();
1003 	return strlen(name);
1004 }
1005 EXPORT_SYMBOL_GPL(gether_get_ifname);
1006 
1007 /**
1008  * gether_cleanup - remove Ethernet-over-USB device
1009  * Context: may sleep
1010  *
1011  * This is called to free all resources allocated by @gether_setup().
1012  */
1013 void gether_cleanup(struct eth_dev *dev)
1014 {
1015 	if (!dev)
1016 		return;
1017 
1018 	unregister_netdev(dev->net);
1019 	flush_work(&dev->work);
1020 	free_netdev(dev->net);
1021 }
1022 EXPORT_SYMBOL_GPL(gether_cleanup);
1023 
1024 /**
1025  * gether_connect - notify network layer that USB link is active
1026  * @link: the USB link, set up with endpoints, descriptors matching
1027  *	current device speed, and any framing wrapper(s) set up.
1028  * Context: irqs blocked
1029  *
1030  * This is called to activate endpoints and let the network layer know
1031  * the connection is active ("carrier detect").  It may cause the I/O
1032  * queues to open and start letting network packets flow, but will in
1033  * any case activate the endpoints so that they respond properly to the
1034  * USB host.
1035  *
1036  * Verify net_device pointer returned using IS_ERR().  If it doesn't
1037  * indicate some error code (negative errno), ep->driver_data values
1038  * have been overwritten.
1039  */
1040 struct net_device *gether_connect(struct gether *link)
1041 {
1042 	struct eth_dev		*dev = link->ioport;
1043 	int			result = 0;
1044 
1045 	if (!dev)
1046 		return ERR_PTR(-EINVAL);
1047 
1048 	link->in_ep->driver_data = dev;
1049 	result = usb_ep_enable(link->in_ep);
1050 	if (result != 0) {
1051 		DBG(dev, "enable %s --> %d\n",
1052 			link->in_ep->name, result);
1053 		goto fail0;
1054 	}
1055 
1056 	link->out_ep->driver_data = dev;
1057 	result = usb_ep_enable(link->out_ep);
1058 	if (result != 0) {
1059 		DBG(dev, "enable %s --> %d\n",
1060 			link->out_ep->name, result);
1061 		goto fail1;
1062 	}
1063 
1064 	if (result == 0)
1065 		result = alloc_requests(dev, link, qlen(dev->gadget,
1066 					dev->qmult));
1067 
1068 	if (result == 0) {
1069 		dev->zlp = link->is_zlp_ok;
1070 		DBG(dev, "qlen %d\n", qlen(dev->gadget, dev->qmult));
1071 
1072 		dev->header_len = link->header_len;
1073 		dev->unwrap = link->unwrap;
1074 		dev->wrap = link->wrap;
1075 
1076 		spin_lock(&dev->lock);
1077 		dev->port_usb = link;
1078 		if (netif_running(dev->net)) {
1079 			if (link->open)
1080 				link->open(link);
1081 		} else {
1082 			if (link->close)
1083 				link->close(link);
1084 		}
1085 		spin_unlock(&dev->lock);
1086 
1087 		netif_carrier_on(dev->net);
1088 		if (netif_running(dev->net))
1089 			eth_start(dev, GFP_ATOMIC);
1090 
1091 	/* on error, disable any endpoints  */
1092 	} else {
1093 		(void) usb_ep_disable(link->out_ep);
1094 fail1:
1095 		(void) usb_ep_disable(link->in_ep);
1096 	}
1097 fail0:
1098 	/* caller is responsible for cleanup on error */
1099 	if (result < 0)
1100 		return ERR_PTR(result);
1101 	return dev->net;
1102 }
1103 EXPORT_SYMBOL_GPL(gether_connect);
1104 
1105 /**
1106  * gether_disconnect - notify network layer that USB link is inactive
1107  * @link: the USB link, on which gether_connect() was called
1108  * Context: irqs blocked
1109  *
1110  * This is called to deactivate endpoints and let the network layer know
1111  * the connection went inactive ("no carrier").
1112  *
1113  * On return, the state is as if gether_connect() had never been called.
1114  * The endpoints are inactive, and accordingly without active USB I/O.
1115  * Pointers to endpoint descriptors and endpoint private data are nulled.
1116  */
1117 void gether_disconnect(struct gether *link)
1118 {
1119 	struct eth_dev		*dev = link->ioport;
1120 	struct usb_request	*req;
1121 
1122 	WARN_ON(!dev);
1123 	if (!dev)
1124 		return;
1125 
1126 	DBG(dev, "%s\n", __func__);
1127 
1128 	netif_stop_queue(dev->net);
1129 	netif_carrier_off(dev->net);
1130 
1131 	/* disable endpoints, forcing (synchronous) completion
1132 	 * of all pending i/o.  then free the request objects
1133 	 * and forget about the endpoints.
1134 	 */
1135 	usb_ep_disable(link->in_ep);
1136 	spin_lock(&dev->req_lock);
1137 	while (!list_empty(&dev->tx_reqs)) {
1138 		req = container_of(dev->tx_reqs.next,
1139 					struct usb_request, list);
1140 		list_del(&req->list);
1141 
1142 		spin_unlock(&dev->req_lock);
1143 		usb_ep_free_request(link->in_ep, req);
1144 		spin_lock(&dev->req_lock);
1145 	}
1146 	spin_unlock(&dev->req_lock);
1147 	link->in_ep->driver_data = NULL;
1148 	link->in_ep->desc = NULL;
1149 
1150 	usb_ep_disable(link->out_ep);
1151 	spin_lock(&dev->req_lock);
1152 	while (!list_empty(&dev->rx_reqs)) {
1153 		req = container_of(dev->rx_reqs.next,
1154 					struct usb_request, list);
1155 		list_del(&req->list);
1156 
1157 		spin_unlock(&dev->req_lock);
1158 		usb_ep_free_request(link->out_ep, req);
1159 		spin_lock(&dev->req_lock);
1160 	}
1161 	spin_unlock(&dev->req_lock);
1162 	link->out_ep->driver_data = NULL;
1163 	link->out_ep->desc = NULL;
1164 
1165 	/* finish forgetting about this USB link episode */
1166 	dev->header_len = 0;
1167 	dev->unwrap = NULL;
1168 	dev->wrap = NULL;
1169 
1170 	spin_lock(&dev->lock);
1171 	dev->port_usb = NULL;
1172 	spin_unlock(&dev->lock);
1173 }
1174 EXPORT_SYMBOL_GPL(gether_disconnect);
1175 
1176 MODULE_LICENSE("GPL");
1177 MODULE_AUTHOR("David Brownell");
1178