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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  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21  */
22 
23 /* #define VERBOSE_DEBUG */
24 
25 #include <linux/kernel.h>
26 #include <linux/utsname.h>
27 #include <linux/device.h>
28 #include <linux/ctype.h>
29 #include <linux/etherdevice.h>
30 #include <linux/ethtool.h>
31 
32 #include "u_ether.h"
33 
34 
35 /*
36  * This component encapsulates the Ethernet link glue needed to provide
37  * one (!) network link through the USB gadget stack, normally "usb0".
38  *
39  * The control and data models are handled by the function driver which
40  * connects to this code; such as CDC Ethernet, "CDC Subset", or RNDIS.
41  * That includes all descriptor and endpoint management.
42  *
43  * Link level addressing is handled by this component using module
44  * parameters; if no such parameters are provided, random link level
45  * addresses are used.  Each end of the link uses one address.  The
46  * host end address is exported in various ways, and is often recorded
47  * in configuration databases.
48  *
49  * The driver which assembles each configuration using such a link is
50  * responsible for ensuring that each configuration includes at most one
51  * instance of is network link.  (The network layer provides ways for
52  * this single "physical" link to be used by multiple virtual links.)
53  */
54 
55 #define UETH__VERSION	"29-May-2008"
56 
57 struct eth_dev {
58 	/* lock is held while accessing port_usb
59 	 * or updating its backlink port_usb->ioport
60 	 */
61 	spinlock_t		lock;
62 	struct gether		*port_usb;
63 
64 	struct net_device	*net;
65 	struct usb_gadget	*gadget;
66 
67 	spinlock_t		req_lock;	/* guard {rx,tx}_reqs */
68 	struct list_head	tx_reqs, rx_reqs;
69 	atomic_t		tx_qlen;
70 
71 	unsigned		header_len;
72 	struct sk_buff		*(*wrap)(struct sk_buff *skb);
73 	int			(*unwrap)(struct sk_buff *skb);
74 
75 	struct work_struct	work;
76 
77 	unsigned long		todo;
78 #define	WORK_RX_MEMORY		0
79 
80 	bool			zlp;
81 	u8			host_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 
91 #ifdef CONFIG_USB_GADGET_DUALSPEED
92 
93 static unsigned qmult = 5;
94 module_param(qmult, uint, S_IRUGO|S_IWUSR);
95 MODULE_PARM_DESC(qmult, "queue length multiplier at high speed");
96 
97 #else	/* full speed (low speed doesn't do bulk) */
98 #define qmult		1
99 #endif
100 
101 /* for dual-speed hardware, use deeper queues at highspeed */
qlen(struct usb_gadget * gadget)102 static inline int qlen(struct usb_gadget *gadget)
103 {
104 	if (gadget_is_dualspeed(gadget) && gadget->speed == USB_SPEED_HIGH)
105 		return qmult * DEFAULT_QLEN;
106 	else
107 		return DEFAULT_QLEN;
108 }
109 
110 /*-------------------------------------------------------------------------*/
111 
112 /* REVISIT there must be a better way than having two sets
113  * of debug calls ...
114  */
115 
116 #undef DBG
117 #undef VDBG
118 #undef ERROR
119 #undef INFO
120 
121 #define xprintk(d, level, fmt, args...) \
122 	printk(level "%s: " fmt , (d)->net->name , ## args)
123 
124 #ifdef DEBUG
125 #undef DEBUG
126 #define DBG(dev, fmt, args...) \
127 	xprintk(dev , KERN_DEBUG , fmt , ## args)
128 #else
129 #define DBG(dev, fmt, args...) \
130 	do { } while (0)
131 #endif /* DEBUG */
132 
133 #ifdef VERBOSE_DEBUG
134 #define VDBG	DBG
135 #else
136 #define VDBG(dev, fmt, args...) \
137 	do { } while (0)
138 #endif /* DEBUG */
139 
140 #define ERROR(dev, fmt, args...) \
141 	xprintk(dev , KERN_ERR , fmt , ## args)
142 #define INFO(dev, fmt, args...) \
143 	xprintk(dev , KERN_INFO , fmt , ## args)
144 
145 /*-------------------------------------------------------------------------*/
146 
147 /* NETWORK DRIVER HOOKUP (to the layer above this driver) */
148 
ueth_change_mtu(struct net_device * net,int new_mtu)149 static int ueth_change_mtu(struct net_device *net, int new_mtu)
150 {
151 	struct eth_dev	*dev = netdev_priv(net);
152 	unsigned long	flags;
153 	int		status = 0;
154 
155 	/* don't change MTU on "live" link (peer won't know) */
156 	spin_lock_irqsave(&dev->lock, flags);
157 	if (dev->port_usb)
158 		status = -EBUSY;
159 	else if (new_mtu <= ETH_HLEN || new_mtu > ETH_FRAME_LEN)
160 		status = -ERANGE;
161 	else
162 		net->mtu = new_mtu;
163 	spin_unlock_irqrestore(&dev->lock, flags);
164 
165 	return status;
166 }
167 
eth_get_drvinfo(struct net_device * net,struct ethtool_drvinfo * p)168 static void eth_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *p)
169 {
170 	struct eth_dev	*dev = netdev_priv(net);
171 
172 	strlcpy(p->driver, "g_ether", sizeof p->driver);
173 	strlcpy(p->version, UETH__VERSION, sizeof p->version);
174 	strlcpy(p->fw_version, dev->gadget->name, sizeof p->fw_version);
175 	strlcpy(p->bus_info, dev_name(&dev->gadget->dev), sizeof p->bus_info);
176 }
177 
eth_get_link(struct net_device * net)178 static u32 eth_get_link(struct net_device *net)
179 {
180 	struct eth_dev	*dev = netdev_priv(net);
181 	return dev->gadget->speed != USB_SPEED_UNKNOWN;
182 }
183 
184 /* REVISIT can also support:
185  *   - WOL (by tracking suspends and issuing remote wakeup)
186  *   - msglevel (implies updated messaging)
187  *   - ... probably more ethtool ops
188  */
189 
190 static struct ethtool_ops ops = {
191 	.get_drvinfo = eth_get_drvinfo,
192 	.get_link = eth_get_link
193 };
194 
defer_kevent(struct eth_dev * dev,int flag)195 static void defer_kevent(struct eth_dev *dev, int flag)
196 {
197 	if (test_and_set_bit(flag, &dev->todo))
198 		return;
199 	if (!schedule_work(&dev->work))
200 		ERROR(dev, "kevent %d may have been dropped\n", flag);
201 	else
202 		DBG(dev, "kevent %d scheduled\n", flag);
203 }
204 
205 static void rx_complete(struct usb_ep *ep, struct usb_request *req);
206 
207 static int
rx_submit(struct eth_dev * dev,struct usb_request * req,gfp_t gfp_flags)208 rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
209 {
210 	struct sk_buff	*skb;
211 	int		retval = -ENOMEM;
212 	size_t		size = 0;
213 	struct usb_ep	*out;
214 	unsigned long	flags;
215 
216 	spin_lock_irqsave(&dev->lock, flags);
217 	if (dev->port_usb)
218 		out = dev->port_usb->out_ep;
219 	else
220 		out = NULL;
221 	spin_unlock_irqrestore(&dev->lock, flags);
222 
223 	if (!out)
224 		return -ENOTCONN;
225 
226 
227 	/* Padding up to RX_EXTRA handles minor disagreements with host.
228 	 * Normally we use the USB "terminate on short read" convention;
229 	 * so allow up to (N*maxpacket), since that memory is normally
230 	 * already allocated.  Some hardware doesn't deal well with short
231 	 * reads (e.g. DMA must be N*maxpacket), so for now don't trim a
232 	 * byte off the end (to force hardware errors on overflow).
233 	 *
234 	 * RNDIS uses internal framing, and explicitly allows senders to
235 	 * pad to end-of-packet.  That's potentially nice for speed, but
236 	 * means receivers can't recover lost synch on their own (because
237 	 * new packets don't only start after a short RX).
238 	 */
239 	size += sizeof(struct ethhdr) + dev->net->mtu + RX_EXTRA;
240 	size += dev->port_usb->header_len;
241 	size += out->maxpacket - 1;
242 	size -= size % out->maxpacket;
243 
244 	skb = alloc_skb(size + NET_IP_ALIGN, gfp_flags);
245 	if (skb == NULL) {
246 		DBG(dev, "no rx skb\n");
247 		goto enomem;
248 	}
249 
250 	/* Some platforms perform better when IP packets are aligned,
251 	 * but on at least one, checksumming fails otherwise.  Note:
252 	 * RNDIS headers involve variable numbers of LE32 values.
253 	 */
254 	skb_reserve(skb, NET_IP_ALIGN);
255 
256 	req->buf = skb->data;
257 	req->length = size;
258 	req->complete = rx_complete;
259 	req->context = skb;
260 
261 	retval = usb_ep_queue(out, req, gfp_flags);
262 	if (retval == -ENOMEM)
263 enomem:
264 		defer_kevent(dev, WORK_RX_MEMORY);
265 	if (retval) {
266 		DBG(dev, "rx submit --> %d\n", retval);
267 		if (skb)
268 			dev_kfree_skb_any(skb);
269 		spin_lock_irqsave(&dev->req_lock, flags);
270 		list_add(&req->list, &dev->rx_reqs);
271 		spin_unlock_irqrestore(&dev->req_lock, flags);
272 	}
273 	return retval;
274 }
275 
rx_complete(struct usb_ep * ep,struct usb_request * req)276 static void rx_complete(struct usb_ep *ep, struct usb_request *req)
277 {
278 	struct sk_buff	*skb = req->context;
279 	struct eth_dev	*dev = ep->driver_data;
280 	int		status = req->status;
281 
282 	switch (status) {
283 
284 	/* normal completion */
285 	case 0:
286 		skb_put(skb, req->actual);
287 		if (dev->unwrap)
288 			status = dev->unwrap(skb);
289 		if (status < 0
290 				|| ETH_HLEN > skb->len
291 				|| skb->len > ETH_FRAME_LEN) {
292 			dev->net->stats.rx_errors++;
293 			dev->net->stats.rx_length_errors++;
294 			DBG(dev, "rx length %d\n", skb->len);
295 			break;
296 		}
297 
298 		skb->protocol = eth_type_trans(skb, dev->net);
299 		dev->net->stats.rx_packets++;
300 		dev->net->stats.rx_bytes += skb->len;
301 
302 		/* no buffer copies needed, unless hardware can't
303 		 * use skb buffers.
304 		 */
305 		status = netif_rx(skb);
306 		skb = NULL;
307 		break;
308 
309 	/* software-driven interface shutdown */
310 	case -ECONNRESET:		/* unlink */
311 	case -ESHUTDOWN:		/* disconnect etc */
312 		VDBG(dev, "rx shutdown, code %d\n", status);
313 		goto quiesce;
314 
315 	/* for hardware automagic (such as pxa) */
316 	case -ECONNABORTED:		/* endpoint reset */
317 		DBG(dev, "rx %s reset\n", ep->name);
318 		defer_kevent(dev, WORK_RX_MEMORY);
319 quiesce:
320 		dev_kfree_skb_any(skb);
321 		goto clean;
322 
323 	/* data overrun */
324 	case -EOVERFLOW:
325 		dev->net->stats.rx_over_errors++;
326 		/* FALLTHROUGH */
327 
328 	default:
329 		dev->net->stats.rx_errors++;
330 		DBG(dev, "rx status %d\n", status);
331 		break;
332 	}
333 
334 	if (skb)
335 		dev_kfree_skb_any(skb);
336 	if (!netif_running(dev->net)) {
337 clean:
338 		spin_lock(&dev->req_lock);
339 		list_add(&req->list, &dev->rx_reqs);
340 		spin_unlock(&dev->req_lock);
341 		req = NULL;
342 	}
343 	if (req)
344 		rx_submit(dev, req, GFP_ATOMIC);
345 }
346 
prealloc(struct list_head * list,struct usb_ep * ep,unsigned n)347 static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
348 {
349 	unsigned		i;
350 	struct usb_request	*req;
351 
352 	if (!n)
353 		return -ENOMEM;
354 
355 	/* queue/recycle up to N requests */
356 	i = n;
357 	list_for_each_entry(req, list, list) {
358 		if (i-- == 0)
359 			goto extra;
360 	}
361 	while (i--) {
362 		req = usb_ep_alloc_request(ep, GFP_ATOMIC);
363 		if (!req)
364 			return list_empty(list) ? -ENOMEM : 0;
365 		list_add(&req->list, list);
366 	}
367 	return 0;
368 
369 extra:
370 	/* free extras */
371 	for (;;) {
372 		struct list_head	*next;
373 
374 		next = req->list.next;
375 		list_del(&req->list);
376 		usb_ep_free_request(ep, req);
377 
378 		if (next == list)
379 			break;
380 
381 		req = container_of(next, struct usb_request, list);
382 	}
383 	return 0;
384 }
385 
alloc_requests(struct eth_dev * dev,struct gether * link,unsigned n)386 static int alloc_requests(struct eth_dev *dev, struct gether *link, unsigned n)
387 {
388 	int	status;
389 
390 	spin_lock(&dev->req_lock);
391 	status = prealloc(&dev->tx_reqs, link->in_ep, n);
392 	if (status < 0)
393 		goto fail;
394 	status = prealloc(&dev->rx_reqs, link->out_ep, n);
395 	if (status < 0)
396 		goto fail;
397 	goto done;
398 fail:
399 	DBG(dev, "can't alloc requests\n");
400 done:
401 	spin_unlock(&dev->req_lock);
402 	return status;
403 }
404 
rx_fill(struct eth_dev * dev,gfp_t gfp_flags)405 static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
406 {
407 	struct usb_request	*req;
408 	unsigned long		flags;
409 
410 	/* fill unused rxq slots with some skb */
411 	spin_lock_irqsave(&dev->req_lock, flags);
412 	while (!list_empty(&dev->rx_reqs)) {
413 		req = container_of(dev->rx_reqs.next,
414 				struct usb_request, list);
415 		list_del_init(&req->list);
416 		spin_unlock_irqrestore(&dev->req_lock, flags);
417 
418 		if (rx_submit(dev, req, gfp_flags) < 0) {
419 			defer_kevent(dev, WORK_RX_MEMORY);
420 			return;
421 		}
422 
423 		spin_lock_irqsave(&dev->req_lock, flags);
424 	}
425 	spin_unlock_irqrestore(&dev->req_lock, flags);
426 }
427 
eth_work(struct work_struct * work)428 static void eth_work(struct work_struct *work)
429 {
430 	struct eth_dev	*dev = container_of(work, struct eth_dev, work);
431 
432 	if (test_and_clear_bit(WORK_RX_MEMORY, &dev->todo)) {
433 		if (netif_running(dev->net))
434 			rx_fill(dev, GFP_KERNEL);
435 	}
436 
437 	if (dev->todo)
438 		DBG(dev, "work done, flags = 0x%lx\n", dev->todo);
439 }
440 
tx_complete(struct usb_ep * ep,struct usb_request * req)441 static void tx_complete(struct usb_ep *ep, struct usb_request *req)
442 {
443 	struct sk_buff	*skb = req->context;
444 	struct eth_dev	*dev = ep->driver_data;
445 
446 	switch (req->status) {
447 	default:
448 		dev->net->stats.tx_errors++;
449 		VDBG(dev, "tx err %d\n", req->status);
450 		/* FALLTHROUGH */
451 	case -ECONNRESET:		/* unlink */
452 	case -ESHUTDOWN:		/* disconnect etc */
453 		break;
454 	case 0:
455 		dev->net->stats.tx_bytes += skb->len;
456 	}
457 	dev->net->stats.tx_packets++;
458 
459 	spin_lock(&dev->req_lock);
460 	list_add(&req->list, &dev->tx_reqs);
461 	spin_unlock(&dev->req_lock);
462 	dev_kfree_skb_any(skb);
463 
464 	atomic_dec(&dev->tx_qlen);
465 	if (netif_carrier_ok(dev->net))
466 		netif_wake_queue(dev->net);
467 }
468 
is_promisc(u16 cdc_filter)469 static inline int is_promisc(u16 cdc_filter)
470 {
471 	return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
472 }
473 
eth_start_xmit(struct sk_buff * skb,struct net_device * net)474 static int eth_start_xmit(struct sk_buff *skb, struct net_device *net)
475 {
476 	struct eth_dev		*dev = netdev_priv(net);
477 	int			length = skb->len;
478 	int			retval;
479 	struct usb_request	*req = NULL;
480 	unsigned long		flags;
481 	struct usb_ep		*in;
482 	u16			cdc_filter;
483 
484 	spin_lock_irqsave(&dev->lock, flags);
485 	if (dev->port_usb) {
486 		in = dev->port_usb->in_ep;
487 		cdc_filter = dev->port_usb->cdc_filter;
488 	} else {
489 		in = NULL;
490 		cdc_filter = 0;
491 	}
492 	spin_unlock_irqrestore(&dev->lock, flags);
493 
494 	if (!in) {
495 		dev_kfree_skb_any(skb);
496 		return 0;
497 	}
498 
499 	/* apply outgoing CDC or RNDIS filters */
500 	if (!is_promisc(cdc_filter)) {
501 		u8		*dest = skb->data;
502 
503 		if (is_multicast_ether_addr(dest)) {
504 			u16	type;
505 
506 			/* ignores USB_CDC_PACKET_TYPE_MULTICAST and host
507 			 * SET_ETHERNET_MULTICAST_FILTERS requests
508 			 */
509 			if (is_broadcast_ether_addr(dest))
510 				type = USB_CDC_PACKET_TYPE_BROADCAST;
511 			else
512 				type = USB_CDC_PACKET_TYPE_ALL_MULTICAST;
513 			if (!(cdc_filter & type)) {
514 				dev_kfree_skb_any(skb);
515 				return 0;
516 			}
517 		}
518 		/* ignores USB_CDC_PACKET_TYPE_DIRECTED */
519 	}
520 
521 	spin_lock_irqsave(&dev->req_lock, flags);
522 	/*
523 	 * this freelist can be empty if an interrupt triggered disconnect()
524 	 * and reconfigured the gadget (shutting down this queue) after the
525 	 * network stack decided to xmit but before we got the spinlock.
526 	 */
527 	if (list_empty(&dev->tx_reqs)) {
528 		spin_unlock_irqrestore(&dev->req_lock, flags);
529 		return 1;
530 	}
531 
532 	req = container_of(dev->tx_reqs.next, struct usb_request, list);
533 	list_del(&req->list);
534 
535 	/* temporarily stop TX queue when the freelist empties */
536 	if (list_empty(&dev->tx_reqs))
537 		netif_stop_queue(net);
538 	spin_unlock_irqrestore(&dev->req_lock, flags);
539 
540 	/* no buffer copies needed, unless the network stack did it
541 	 * or the hardware can't use skb buffers.
542 	 * or there's not enough space for extra headers we need
543 	 */
544 	if (dev->wrap) {
545 		struct sk_buff	*skb_new;
546 
547 		skb_new = dev->wrap(skb);
548 		if (!skb_new)
549 			goto drop;
550 
551 		dev_kfree_skb_any(skb);
552 		skb = skb_new;
553 		length = skb->len;
554 	}
555 	req->buf = skb->data;
556 	req->context = skb;
557 	req->complete = tx_complete;
558 
559 	/* use zlp framing on tx for strict CDC-Ether conformance,
560 	 * though any robust network rx path ignores extra padding.
561 	 * and some hardware doesn't like to write zlps.
562 	 */
563 	req->zero = 1;
564 	if (!dev->zlp && (length % in->maxpacket) == 0)
565 		length++;
566 
567 	req->length = length;
568 
569 	/* throttle highspeed IRQ rate back slightly */
570 	if (gadget_is_dualspeed(dev->gadget))
571 		req->no_interrupt = (dev->gadget->speed == USB_SPEED_HIGH)
572 			? ((atomic_read(&dev->tx_qlen) % qmult) != 0)
573 			: 0;
574 
575 	retval = usb_ep_queue(in, req, GFP_ATOMIC);
576 	switch (retval) {
577 	default:
578 		DBG(dev, "tx queue err %d\n", retval);
579 		break;
580 	case 0:
581 		net->trans_start = jiffies;
582 		atomic_inc(&dev->tx_qlen);
583 	}
584 
585 	if (retval) {
586 drop:
587 		dev->net->stats.tx_dropped++;
588 		dev_kfree_skb_any(skb);
589 		spin_lock_irqsave(&dev->req_lock, flags);
590 		if (list_empty(&dev->tx_reqs))
591 			netif_start_queue(net);
592 		list_add(&req->list, &dev->tx_reqs);
593 		spin_unlock_irqrestore(&dev->req_lock, flags);
594 	}
595 	return 0;
596 }
597 
598 /*-------------------------------------------------------------------------*/
599 
eth_start(struct eth_dev * dev,gfp_t gfp_flags)600 static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
601 {
602 	DBG(dev, "%s\n", __func__);
603 
604 	/* fill the rx queue */
605 	rx_fill(dev, gfp_flags);
606 
607 	/* and open the tx floodgates */
608 	atomic_set(&dev->tx_qlen, 0);
609 	netif_wake_queue(dev->net);
610 }
611 
eth_open(struct net_device * net)612 static int eth_open(struct net_device *net)
613 {
614 	struct eth_dev	*dev = netdev_priv(net);
615 	struct gether	*link;
616 
617 	DBG(dev, "%s\n", __func__);
618 	if (netif_carrier_ok(dev->net))
619 		eth_start(dev, GFP_KERNEL);
620 
621 	spin_lock_irq(&dev->lock);
622 	link = dev->port_usb;
623 	if (link && link->open)
624 		link->open(link);
625 	spin_unlock_irq(&dev->lock);
626 
627 	return 0;
628 }
629 
eth_stop(struct net_device * net)630 static int eth_stop(struct net_device *net)
631 {
632 	struct eth_dev	*dev = netdev_priv(net);
633 	unsigned long	flags;
634 
635 	VDBG(dev, "%s\n", __func__);
636 	netif_stop_queue(net);
637 
638 	DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
639 		dev->net->stats.rx_packets, dev->net->stats.tx_packets,
640 		dev->net->stats.rx_errors, dev->net->stats.tx_errors
641 		);
642 
643 	/* ensure there are no more active requests */
644 	spin_lock_irqsave(&dev->lock, flags);
645 	if (dev->port_usb) {
646 		struct gether	*link = dev->port_usb;
647 
648 		if (link->close)
649 			link->close(link);
650 
651 		/* NOTE:  we have no abort-queue primitive we could use
652 		 * to cancel all pending I/O.  Instead, we disable then
653 		 * reenable the endpoints ... this idiom may leave toggle
654 		 * wrong, but that's a self-correcting error.
655 		 *
656 		 * REVISIT:  we *COULD* just let the transfers complete at
657 		 * their own pace; the network stack can handle old packets.
658 		 * For the moment we leave this here, since it works.
659 		 */
660 		usb_ep_disable(link->in_ep);
661 		usb_ep_disable(link->out_ep);
662 		if (netif_carrier_ok(net)) {
663 			DBG(dev, "host still using in/out endpoints\n");
664 			usb_ep_enable(link->in_ep, link->in);
665 			usb_ep_enable(link->out_ep, link->out);
666 		}
667 	}
668 	spin_unlock_irqrestore(&dev->lock, flags);
669 
670 	return 0;
671 }
672 
673 /*-------------------------------------------------------------------------*/
674 
675 /* initial value, changed by "ifconfig usb0 hw ether xx:xx:xx:xx:xx:xx" */
676 static char *dev_addr;
677 module_param(dev_addr, charp, S_IRUGO);
678 MODULE_PARM_DESC(dev_addr, "Device Ethernet Address");
679 
680 /* this address is invisible to ifconfig */
681 static char *host_addr;
682 module_param(host_addr, charp, S_IRUGO);
683 MODULE_PARM_DESC(host_addr, "Host Ethernet Address");
684 
685 
nibble(unsigned char c)686 static u8 __init nibble(unsigned char c)
687 {
688 	if (isdigit(c))
689 		return c - '0';
690 	c = toupper(c);
691 	if (isxdigit(c))
692 		return 10 + c - 'A';
693 	return 0;
694 }
695 
get_ether_addr(const char * str,u8 * dev_addr)696 static int __init get_ether_addr(const char *str, u8 *dev_addr)
697 {
698 	if (str) {
699 		unsigned	i;
700 
701 		for (i = 0; i < 6; i++) {
702 			unsigned char num;
703 
704 			if ((*str == '.') || (*str == ':'))
705 				str++;
706 			num = nibble(*str++) << 4;
707 			num |= (nibble(*str++));
708 			dev_addr [i] = num;
709 		}
710 		if (is_valid_ether_addr(dev_addr))
711 			return 0;
712 	}
713 	random_ether_addr(dev_addr);
714 	return 1;
715 }
716 
717 static struct eth_dev *the_dev;
718 
719 static const struct net_device_ops eth_netdev_ops = {
720 	.ndo_open		= eth_open,
721 	.ndo_stop		= eth_stop,
722 	.ndo_start_xmit		= eth_start_xmit,
723 	.ndo_change_mtu		= ueth_change_mtu,
724 	.ndo_set_mac_address 	= eth_mac_addr,
725 	.ndo_validate_addr	= eth_validate_addr,
726 };
727 
728 /**
729  * gether_setup - initialize one ethernet-over-usb link
730  * @g: gadget to associated with these links
731  * @ethaddr: NULL, or a buffer in which the ethernet address of the
732  *	host side of the link is recorded
733  * Context: may sleep
734  *
735  * This sets up the single network link that may be exported by a
736  * gadget driver using this framework.  The link layer addresses are
737  * set up using module parameters.
738  *
739  * Returns negative errno, or zero on success
740  */
gether_setup(struct usb_gadget * g,u8 ethaddr[ETH_ALEN])741 int __init gether_setup(struct usb_gadget *g, u8 ethaddr[ETH_ALEN])
742 {
743 	struct eth_dev		*dev;
744 	struct net_device	*net;
745 	int			status;
746 
747 	if (the_dev)
748 		return -EBUSY;
749 
750 	net = alloc_etherdev(sizeof *dev);
751 	if (!net)
752 		return -ENOMEM;
753 
754 	dev = netdev_priv(net);
755 	spin_lock_init(&dev->lock);
756 	spin_lock_init(&dev->req_lock);
757 	INIT_WORK(&dev->work, eth_work);
758 	INIT_LIST_HEAD(&dev->tx_reqs);
759 	INIT_LIST_HEAD(&dev->rx_reqs);
760 
761 	/* network device setup */
762 	dev->net = net;
763 	strcpy(net->name, "usb%d");
764 
765 	if (get_ether_addr(dev_addr, net->dev_addr))
766 		dev_warn(&g->dev,
767 			"using random %s ethernet address\n", "self");
768 	if (get_ether_addr(host_addr, dev->host_mac))
769 		dev_warn(&g->dev,
770 			"using random %s ethernet address\n", "host");
771 
772 	if (ethaddr)
773 		memcpy(ethaddr, dev->host_mac, ETH_ALEN);
774 
775 	net->netdev_ops = &eth_netdev_ops;
776 
777 	SET_ETHTOOL_OPS(net, &ops);
778 
779 	/* two kinds of host-initiated state changes:
780 	 *  - iff DATA transfer is active, carrier is "on"
781 	 *  - tx queueing enabled if open *and* carrier is "on"
782 	 */
783 	netif_stop_queue(net);
784 	netif_carrier_off(net);
785 
786 	dev->gadget = g;
787 	SET_NETDEV_DEV(net, &g->dev);
788 
789 	status = register_netdev(net);
790 	if (status < 0) {
791 		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
792 		free_netdev(net);
793 	} else {
794 		INFO(dev, "MAC %pM\n", net->dev_addr);
795 		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
796 
797 		the_dev = dev;
798 	}
799 
800 	return status;
801 }
802 
803 /**
804  * gether_cleanup - remove Ethernet-over-USB device
805  * Context: may sleep
806  *
807  * This is called to free all resources allocated by @gether_setup().
808  */
gether_cleanup(void)809 void gether_cleanup(void)
810 {
811 	if (!the_dev)
812 		return;
813 
814 	unregister_netdev(the_dev->net);
815 	free_netdev(the_dev->net);
816 
817 	/* assuming we used keventd, it must quiesce too */
818 	flush_scheduled_work();
819 
820 	the_dev = NULL;
821 }
822 
823 
824 /**
825  * gether_connect - notify network layer that USB link is active
826  * @link: the USB link, set up with endpoints, descriptors matching
827  *	current device speed, and any framing wrapper(s) set up.
828  * Context: irqs blocked
829  *
830  * This is called to activate endpoints and let the network layer know
831  * the connection is active ("carrier detect").  It may cause the I/O
832  * queues to open and start letting network packets flow, but will in
833  * any case activate the endpoints so that they respond properly to the
834  * USB host.
835  *
836  * Verify net_device pointer returned using IS_ERR().  If it doesn't
837  * indicate some error code (negative errno), ep->driver_data values
838  * have been overwritten.
839  */
gether_connect(struct gether * link)840 struct net_device *gether_connect(struct gether *link)
841 {
842 	struct eth_dev		*dev = the_dev;
843 	int			result = 0;
844 
845 	if (!dev)
846 		return ERR_PTR(-EINVAL);
847 
848 	link->in_ep->driver_data = dev;
849 	result = usb_ep_enable(link->in_ep, link->in);
850 	if (result != 0) {
851 		DBG(dev, "enable %s --> %d\n",
852 			link->in_ep->name, result);
853 		goto fail0;
854 	}
855 
856 	link->out_ep->driver_data = dev;
857 	result = usb_ep_enable(link->out_ep, link->out);
858 	if (result != 0) {
859 		DBG(dev, "enable %s --> %d\n",
860 			link->out_ep->name, result);
861 		goto fail1;
862 	}
863 
864 	if (result == 0)
865 		result = alloc_requests(dev, link, qlen(dev->gadget));
866 
867 	if (result == 0) {
868 		dev->zlp = link->is_zlp_ok;
869 		DBG(dev, "qlen %d\n", qlen(dev->gadget));
870 
871 		dev->header_len = link->header_len;
872 		dev->unwrap = link->unwrap;
873 		dev->wrap = link->wrap;
874 
875 		spin_lock(&dev->lock);
876 		dev->port_usb = link;
877 		link->ioport = dev;
878 		if (netif_running(dev->net)) {
879 			if (link->open)
880 				link->open(link);
881 		} else {
882 			if (link->close)
883 				link->close(link);
884 		}
885 		spin_unlock(&dev->lock);
886 
887 		netif_carrier_on(dev->net);
888 		if (netif_running(dev->net))
889 			eth_start(dev, GFP_ATOMIC);
890 
891 	/* on error, disable any endpoints  */
892 	} else {
893 		(void) usb_ep_disable(link->out_ep);
894 fail1:
895 		(void) usb_ep_disable(link->in_ep);
896 	}
897 fail0:
898 	/* caller is responsible for cleanup on error */
899 	if (result < 0)
900 		return ERR_PTR(result);
901 	return dev->net;
902 }
903 
904 /**
905  * gether_disconnect - notify network layer that USB link is inactive
906  * @link: the USB link, on which gether_connect() was called
907  * Context: irqs blocked
908  *
909  * This is called to deactivate endpoints and let the network layer know
910  * the connection went inactive ("no carrier").
911  *
912  * On return, the state is as if gether_connect() had never been called.
913  * The endpoints are inactive, and accordingly without active USB I/O.
914  * Pointers to endpoint descriptors and endpoint private data are nulled.
915  */
gether_disconnect(struct gether * link)916 void gether_disconnect(struct gether *link)
917 {
918 	struct eth_dev		*dev = link->ioport;
919 	struct usb_request	*req;
920 
921 	WARN_ON(!dev);
922 	if (!dev)
923 		return;
924 
925 	DBG(dev, "%s\n", __func__);
926 
927 	netif_stop_queue(dev->net);
928 	netif_carrier_off(dev->net);
929 
930 	/* disable endpoints, forcing (synchronous) completion
931 	 * of all pending i/o.  then free the request objects
932 	 * and forget about the endpoints.
933 	 */
934 	usb_ep_disable(link->in_ep);
935 	spin_lock(&dev->req_lock);
936 	while (!list_empty(&dev->tx_reqs)) {
937 		req = container_of(dev->tx_reqs.next,
938 					struct usb_request, list);
939 		list_del(&req->list);
940 
941 		spin_unlock(&dev->req_lock);
942 		usb_ep_free_request(link->in_ep, req);
943 		spin_lock(&dev->req_lock);
944 	}
945 	spin_unlock(&dev->req_lock);
946 	link->in_ep->driver_data = NULL;
947 	link->in = NULL;
948 
949 	usb_ep_disable(link->out_ep);
950 	spin_lock(&dev->req_lock);
951 	while (!list_empty(&dev->rx_reqs)) {
952 		req = container_of(dev->rx_reqs.next,
953 					struct usb_request, list);
954 		list_del(&req->list);
955 
956 		spin_unlock(&dev->req_lock);
957 		usb_ep_free_request(link->out_ep, req);
958 		spin_lock(&dev->req_lock);
959 	}
960 	spin_unlock(&dev->req_lock);
961 	link->out_ep->driver_data = NULL;
962 	link->out = NULL;
963 
964 	/* finish forgetting about this USB link episode */
965 	dev->header_len = 0;
966 	dev->unwrap = NULL;
967 	dev->wrap = NULL;
968 
969 	spin_lock(&dev->lock);
970 	dev->port_usb = NULL;
971 	link->ioport = NULL;
972 	spin_unlock(&dev->lock);
973 }
974