1// SPDX-License-Identifier: GPL-2.0
2/*
3 * f_phonet.c -- USB CDC Phonet function
4 *
5 * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
6 *
7 * Author: R��mi Denis-Courmont
8 */
9
10#include <linux/mm.h>
11#include <linux/slab.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/device.h>
15
16#include <linux/netdevice.h>
17#include <linux/if_ether.h>
18#include <linux/if_phonet.h>
19#include <linux/if_arp.h>
20
21#include <linux/usb/ch9.h>
22#include <linux/usb/cdc.h>
23#include <linux/usb/composite.h>
24
25#include "u_phonet.h"
26#include "u_ether.h"
27
28#define PN_MEDIA_USB	0x1B
29#define MAXPACKET	512
30#if (PAGE_SIZE % MAXPACKET)
31#error MAXPACKET must divide PAGE_SIZE!
32#endif
33
34/*-------------------------------------------------------------------------*/
35
36struct phonet_port {
37	struct f_phonet			*usb;
38	spinlock_t			lock;
39};
40
41struct f_phonet {
42	struct usb_function		function;
43	struct {
44		struct sk_buff		*skb;
45		spinlock_t		lock;
46	} rx;
47	struct net_device		*dev;
48	struct usb_ep			*in_ep, *out_ep;
49
50	struct usb_request		*in_req;
51	struct usb_request		*out_reqv[];
52};
53
54static int phonet_rxq_size = 17;
55
56static inline struct f_phonet *func_to_pn(struct usb_function *f)
57{
58	return container_of(f, struct f_phonet, function);
59}
60
61/*-------------------------------------------------------------------------*/
62
63#define USB_CDC_SUBCLASS_PHONET	0xfe
64#define USB_CDC_PHONET_TYPE	0xab
65
66static struct usb_interface_descriptor
67pn_control_intf_desc = {
68	.bLength =		sizeof pn_control_intf_desc,
69	.bDescriptorType =	USB_DT_INTERFACE,
70
71	/* .bInterfaceNumber =	DYNAMIC, */
72	.bInterfaceClass =	USB_CLASS_COMM,
73	.bInterfaceSubClass =	USB_CDC_SUBCLASS_PHONET,
74};
75
76static const struct usb_cdc_header_desc
77pn_header_desc = {
78	.bLength =		sizeof pn_header_desc,
79	.bDescriptorType =	USB_DT_CS_INTERFACE,
80	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
81	.bcdCDC =		cpu_to_le16(0x0110),
82};
83
84static const struct usb_cdc_header_desc
85pn_phonet_desc = {
86	.bLength =		sizeof pn_phonet_desc,
87	.bDescriptorType =	USB_DT_CS_INTERFACE,
88	.bDescriptorSubType =	USB_CDC_PHONET_TYPE,
89	.bcdCDC =		cpu_to_le16(0x1505), /* ??? */
90};
91
92static struct usb_cdc_union_desc
93pn_union_desc = {
94	.bLength =		sizeof pn_union_desc,
95	.bDescriptorType =	USB_DT_CS_INTERFACE,
96	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
97
98	/* .bMasterInterface0 =	DYNAMIC, */
99	/* .bSlaveInterface0 =	DYNAMIC, */
100};
101
102static struct usb_interface_descriptor
103pn_data_nop_intf_desc = {
104	.bLength =		sizeof pn_data_nop_intf_desc,
105	.bDescriptorType =	USB_DT_INTERFACE,
106
107	/* .bInterfaceNumber =	DYNAMIC, */
108	.bAlternateSetting =	0,
109	.bNumEndpoints =	0,
110	.bInterfaceClass =	USB_CLASS_CDC_DATA,
111};
112
113static struct usb_interface_descriptor
114pn_data_intf_desc = {
115	.bLength =		sizeof pn_data_intf_desc,
116	.bDescriptorType =	USB_DT_INTERFACE,
117
118	/* .bInterfaceNumber =	DYNAMIC, */
119	.bAlternateSetting =	1,
120	.bNumEndpoints =	2,
121	.bInterfaceClass =	USB_CLASS_CDC_DATA,
122};
123
124static struct usb_endpoint_descriptor
125pn_fs_sink_desc = {
126	.bLength =		USB_DT_ENDPOINT_SIZE,
127	.bDescriptorType =	USB_DT_ENDPOINT,
128
129	.bEndpointAddress =	USB_DIR_OUT,
130	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
131};
132
133static struct usb_endpoint_descriptor
134pn_hs_sink_desc = {
135	.bLength =		USB_DT_ENDPOINT_SIZE,
136	.bDescriptorType =	USB_DT_ENDPOINT,
137
138	.bEndpointAddress =	USB_DIR_OUT,
139	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
140	.wMaxPacketSize =	cpu_to_le16(MAXPACKET),
141};
142
143static struct usb_endpoint_descriptor
144pn_fs_source_desc = {
145	.bLength =		USB_DT_ENDPOINT_SIZE,
146	.bDescriptorType =	USB_DT_ENDPOINT,
147
148	.bEndpointAddress =	USB_DIR_IN,
149	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
150};
151
152static struct usb_endpoint_descriptor
153pn_hs_source_desc = {
154	.bLength =		USB_DT_ENDPOINT_SIZE,
155	.bDescriptorType =	USB_DT_ENDPOINT,
156
157	.bEndpointAddress =	USB_DIR_IN,
158	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
159	.wMaxPacketSize =	cpu_to_le16(512),
160};
161
162static struct usb_descriptor_header *fs_pn_function[] = {
163	(struct usb_descriptor_header *) &pn_control_intf_desc,
164	(struct usb_descriptor_header *) &pn_header_desc,
165	(struct usb_descriptor_header *) &pn_phonet_desc,
166	(struct usb_descriptor_header *) &pn_union_desc,
167	(struct usb_descriptor_header *) &pn_data_nop_intf_desc,
168	(struct usb_descriptor_header *) &pn_data_intf_desc,
169	(struct usb_descriptor_header *) &pn_fs_sink_desc,
170	(struct usb_descriptor_header *) &pn_fs_source_desc,
171	NULL,
172};
173
174static struct usb_descriptor_header *hs_pn_function[] = {
175	(struct usb_descriptor_header *) &pn_control_intf_desc,
176	(struct usb_descriptor_header *) &pn_header_desc,
177	(struct usb_descriptor_header *) &pn_phonet_desc,
178	(struct usb_descriptor_header *) &pn_union_desc,
179	(struct usb_descriptor_header *) &pn_data_nop_intf_desc,
180	(struct usb_descriptor_header *) &pn_data_intf_desc,
181	(struct usb_descriptor_header *) &pn_hs_sink_desc,
182	(struct usb_descriptor_header *) &pn_hs_source_desc,
183	NULL,
184};
185
186/*-------------------------------------------------------------------------*/
187
188static int pn_net_open(struct net_device *dev)
189{
190	netif_wake_queue(dev);
191	return 0;
192}
193
194static int pn_net_close(struct net_device *dev)
195{
196	netif_stop_queue(dev);
197	return 0;
198}
199
200static void pn_tx_complete(struct usb_ep *ep, struct usb_request *req)
201{
202	struct f_phonet *fp = ep->driver_data;
203	struct net_device *dev = fp->dev;
204	struct sk_buff *skb = req->context;
205
206	switch (req->status) {
207	case 0:
208		dev->stats.tx_packets++;
209		dev->stats.tx_bytes += skb->len;
210		break;
211
212	case -ESHUTDOWN: /* disconnected */
213	case -ECONNRESET: /* disabled */
214		dev->stats.tx_aborted_errors++;
215		fallthrough;
216	default:
217		dev->stats.tx_errors++;
218	}
219
220	dev_kfree_skb_any(skb);
221	netif_wake_queue(dev);
222}
223
224static netdev_tx_t pn_net_xmit(struct sk_buff *skb, struct net_device *dev)
225{
226	struct phonet_port *port = netdev_priv(dev);
227	struct f_phonet *fp;
228	struct usb_request *req;
229	unsigned long flags;
230
231	if (skb->protocol != htons(ETH_P_PHONET))
232		goto out;
233
234	spin_lock_irqsave(&port->lock, flags);
235	fp = port->usb;
236	if (unlikely(!fp)) /* race with carrier loss */
237		goto out_unlock;
238
239	req = fp->in_req;
240	req->buf = skb->data;
241	req->length = skb->len;
242	req->complete = pn_tx_complete;
243	req->zero = 1;
244	req->context = skb;
245
246	if (unlikely(usb_ep_queue(fp->in_ep, req, GFP_ATOMIC)))
247		goto out_unlock;
248
249	netif_stop_queue(dev);
250	skb = NULL;
251
252out_unlock:
253	spin_unlock_irqrestore(&port->lock, flags);
254out:
255	if (unlikely(skb)) {
256		dev_kfree_skb(skb);
257		dev->stats.tx_dropped++;
258	}
259	return NETDEV_TX_OK;
260}
261
262static const struct net_device_ops pn_netdev_ops = {
263	.ndo_open	= pn_net_open,
264	.ndo_stop	= pn_net_close,
265	.ndo_start_xmit	= pn_net_xmit,
266};
267
268static void pn_net_setup(struct net_device *dev)
269{
270	const u8 addr = PN_MEDIA_USB;
271
272	dev->features		= 0;
273	dev->type		= ARPHRD_PHONET;
274	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
275	dev->mtu		= PHONET_DEV_MTU;
276	dev->min_mtu		= PHONET_MIN_MTU;
277	dev->max_mtu		= PHONET_MAX_MTU;
278	dev->hard_header_len	= 1;
279	dev->addr_len		= 1;
280	dev_addr_set(dev, &addr);
281
282	dev->tx_queue_len	= 1;
283
284	dev->netdev_ops		= &pn_netdev_ops;
285	dev->needs_free_netdev	= true;
286	dev->header_ops		= &phonet_header_ops;
287}
288
289/*-------------------------------------------------------------------------*/
290
291/*
292 * Queue buffer for data from the host
293 */
294static int
295pn_rx_submit(struct f_phonet *fp, struct usb_request *req, gfp_t gfp_flags)
296{
297	struct page *page;
298	int err;
299
300	page = __dev_alloc_page(gfp_flags | __GFP_NOMEMALLOC);
301	if (!page)
302		return -ENOMEM;
303
304	req->buf = page_address(page);
305	req->length = PAGE_SIZE;
306	req->context = page;
307
308	err = usb_ep_queue(fp->out_ep, req, gfp_flags);
309	if (unlikely(err))
310		put_page(page);
311	return err;
312}
313
314static void pn_rx_complete(struct usb_ep *ep, struct usb_request *req)
315{
316	struct f_phonet *fp = ep->driver_data;
317	struct net_device *dev = fp->dev;
318	struct page *page = req->context;
319	struct sk_buff *skb;
320	unsigned long flags;
321	int status = req->status;
322
323	switch (status) {
324	case 0:
325		spin_lock_irqsave(&fp->rx.lock, flags);
326		skb = fp->rx.skb;
327		if (!skb)
328			skb = fp->rx.skb = netdev_alloc_skb(dev, 12);
329		if (req->actual < req->length) /* Last fragment */
330			fp->rx.skb = NULL;
331		spin_unlock_irqrestore(&fp->rx.lock, flags);
332
333		if (unlikely(!skb))
334			break;
335
336		if (skb->len == 0) { /* First fragment */
337			skb->protocol = htons(ETH_P_PHONET);
338			skb_reset_mac_header(skb);
339			/* Can't use pskb_pull() on page in IRQ */
340			skb_put_data(skb, page_address(page), 1);
341		}
342
343		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
344				skb->len <= 1, req->actual, PAGE_SIZE);
345		page = NULL;
346
347		if (req->actual < req->length) { /* Last fragment */
348			skb->dev = dev;
349			dev->stats.rx_packets++;
350			dev->stats.rx_bytes += skb->len;
351
352			netif_rx(skb);
353		}
354		break;
355
356	/* Do not resubmit in these cases: */
357	case -ESHUTDOWN: /* disconnect */
358	case -ECONNABORTED: /* hw reset */
359	case -ECONNRESET: /* dequeued (unlink or netif down) */
360		req = NULL;
361		break;
362
363	/* Do resubmit in these cases: */
364	case -EOVERFLOW: /* request buffer overflow */
365		dev->stats.rx_over_errors++;
366		fallthrough;
367	default:
368		dev->stats.rx_errors++;
369		break;
370	}
371
372	if (page)
373		put_page(page);
374	if (req)
375		pn_rx_submit(fp, req, GFP_ATOMIC);
376}
377
378/*-------------------------------------------------------------------------*/
379
380static void __pn_reset(struct usb_function *f)
381{
382	struct f_phonet *fp = func_to_pn(f);
383	struct net_device *dev = fp->dev;
384	struct phonet_port *port = netdev_priv(dev);
385
386	netif_carrier_off(dev);
387	port->usb = NULL;
388
389	usb_ep_disable(fp->out_ep);
390	usb_ep_disable(fp->in_ep);
391	if (fp->rx.skb) {
392		dev_kfree_skb_irq(fp->rx.skb);
393		fp->rx.skb = NULL;
394	}
395}
396
397static int pn_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
398{
399	struct f_phonet *fp = func_to_pn(f);
400	struct usb_gadget *gadget = fp->function.config->cdev->gadget;
401
402	if (intf == pn_control_intf_desc.bInterfaceNumber)
403		/* control interface, no altsetting */
404		return (alt > 0) ? -EINVAL : 0;
405
406	if (intf == pn_data_intf_desc.bInterfaceNumber) {
407		struct net_device *dev = fp->dev;
408		struct phonet_port *port = netdev_priv(dev);
409
410		/* data intf (0: inactive, 1: active) */
411		if (alt > 1)
412			return -EINVAL;
413
414		spin_lock(&port->lock);
415
416		if (fp->in_ep->enabled)
417			__pn_reset(f);
418
419		if (alt == 1) {
420			int i;
421
422			if (config_ep_by_speed(gadget, f, fp->in_ep) ||
423			    config_ep_by_speed(gadget, f, fp->out_ep)) {
424				fp->in_ep->desc = NULL;
425				fp->out_ep->desc = NULL;
426				spin_unlock(&port->lock);
427				return -EINVAL;
428			}
429			usb_ep_enable(fp->out_ep);
430			usb_ep_enable(fp->in_ep);
431
432			port->usb = fp;
433			fp->out_ep->driver_data = fp;
434			fp->in_ep->driver_data = fp;
435
436			netif_carrier_on(dev);
437			for (i = 0; i < phonet_rxq_size; i++)
438				pn_rx_submit(fp, fp->out_reqv[i], GFP_ATOMIC);
439		}
440		spin_unlock(&port->lock);
441		return 0;
442	}
443
444	return -EINVAL;
445}
446
447static int pn_get_alt(struct usb_function *f, unsigned intf)
448{
449	struct f_phonet *fp = func_to_pn(f);
450
451	if (intf == pn_control_intf_desc.bInterfaceNumber)
452		return 0;
453
454	if (intf == pn_data_intf_desc.bInterfaceNumber) {
455		struct phonet_port *port = netdev_priv(fp->dev);
456		u8 alt;
457
458		spin_lock(&port->lock);
459		alt = port->usb != NULL;
460		spin_unlock(&port->lock);
461		return alt;
462	}
463
464	return -EINVAL;
465}
466
467static void pn_disconnect(struct usb_function *f)
468{
469	struct f_phonet *fp = func_to_pn(f);
470	struct phonet_port *port = netdev_priv(fp->dev);
471	unsigned long flags;
472
473	/* remain disabled until set_alt */
474	spin_lock_irqsave(&port->lock, flags);
475	__pn_reset(f);
476	spin_unlock_irqrestore(&port->lock, flags);
477}
478
479/*-------------------------------------------------------------------------*/
480
481static int pn_bind(struct usb_configuration *c, struct usb_function *f)
482{
483	struct usb_composite_dev *cdev = c->cdev;
484	struct usb_gadget *gadget = cdev->gadget;
485	struct f_phonet *fp = func_to_pn(f);
486	struct usb_ep *ep;
487	int status, i;
488
489	struct f_phonet_opts *phonet_opts;
490
491	phonet_opts = container_of(f->fi, struct f_phonet_opts, func_inst);
492
493	/*
494	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
495	 * configurations are bound in sequence with list_for_each_entry,
496	 * in each configuration its functions are bound in sequence
497	 * with list_for_each_entry, so we assume no race condition
498	 * with regard to phonet_opts->bound access
499	 */
500	if (!phonet_opts->bound) {
501		gphonet_set_gadget(phonet_opts->net, gadget);
502		status = gphonet_register_netdev(phonet_opts->net);
503		if (status)
504			return status;
505		phonet_opts->bound = true;
506	}
507
508	/* Reserve interface IDs */
509	status = usb_interface_id(c, f);
510	if (status < 0)
511		goto err;
512	pn_control_intf_desc.bInterfaceNumber = status;
513	pn_union_desc.bMasterInterface0 = status;
514
515	status = usb_interface_id(c, f);
516	if (status < 0)
517		goto err;
518	pn_data_nop_intf_desc.bInterfaceNumber = status;
519	pn_data_intf_desc.bInterfaceNumber = status;
520	pn_union_desc.bSlaveInterface0 = status;
521
522	/* Reserve endpoints */
523	status = -ENODEV;
524	ep = usb_ep_autoconfig(gadget, &pn_fs_sink_desc);
525	if (!ep)
526		goto err;
527	fp->out_ep = ep;
528
529	ep = usb_ep_autoconfig(gadget, &pn_fs_source_desc);
530	if (!ep)
531		goto err;
532	fp->in_ep = ep;
533
534	pn_hs_sink_desc.bEndpointAddress = pn_fs_sink_desc.bEndpointAddress;
535	pn_hs_source_desc.bEndpointAddress = pn_fs_source_desc.bEndpointAddress;
536
537	/* Do not try to bind Phonet twice... */
538	status = usb_assign_descriptors(f, fs_pn_function, hs_pn_function,
539			NULL, NULL);
540	if (status)
541		goto err;
542
543	/* Incoming USB requests */
544	status = -ENOMEM;
545	for (i = 0; i < phonet_rxq_size; i++) {
546		struct usb_request *req;
547
548		req = usb_ep_alloc_request(fp->out_ep, GFP_KERNEL);
549		if (!req)
550			goto err_req;
551
552		req->complete = pn_rx_complete;
553		fp->out_reqv[i] = req;
554	}
555
556	/* Outgoing USB requests */
557	fp->in_req = usb_ep_alloc_request(fp->in_ep, GFP_KERNEL);
558	if (!fp->in_req)
559		goto err_req;
560
561	INFO(cdev, "USB CDC Phonet function\n");
562	INFO(cdev, "using %s, OUT %s, IN %s\n", cdev->gadget->name,
563		fp->out_ep->name, fp->in_ep->name);
564	return 0;
565
566err_req:
567	for (i = 0; i < phonet_rxq_size && fp->out_reqv[i]; i++)
568		usb_ep_free_request(fp->out_ep, fp->out_reqv[i]);
569	usb_free_all_descriptors(f);
570err:
571	ERROR(cdev, "USB CDC Phonet: cannot autoconfigure\n");
572	return status;
573}
574
575static inline struct f_phonet_opts *to_f_phonet_opts(struct config_item *item)
576{
577	return container_of(to_config_group(item), struct f_phonet_opts,
578			func_inst.group);
579}
580
581static void phonet_attr_release(struct config_item *item)
582{
583	struct f_phonet_opts *opts = to_f_phonet_opts(item);
584
585	usb_put_function_instance(&opts->func_inst);
586}
587
588static struct configfs_item_operations phonet_item_ops = {
589	.release		= phonet_attr_release,
590};
591
592static ssize_t f_phonet_ifname_show(struct config_item *item, char *page)
593{
594	return gether_get_ifname(to_f_phonet_opts(item)->net, page, PAGE_SIZE);
595}
596
597CONFIGFS_ATTR_RO(f_phonet_, ifname);
598
599static struct configfs_attribute *phonet_attrs[] = {
600	&f_phonet_attr_ifname,
601	NULL,
602};
603
604static const struct config_item_type phonet_func_type = {
605	.ct_item_ops	= &phonet_item_ops,
606	.ct_attrs	= phonet_attrs,
607	.ct_owner	= THIS_MODULE,
608};
609
610static void phonet_free_inst(struct usb_function_instance *f)
611{
612	struct f_phonet_opts *opts;
613
614	opts = container_of(f, struct f_phonet_opts, func_inst);
615	if (opts->bound)
616		gphonet_cleanup(opts->net);
617	else
618		free_netdev(opts->net);
619	kfree(opts);
620}
621
622static struct usb_function_instance *phonet_alloc_inst(void)
623{
624	struct f_phonet_opts *opts;
625
626	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
627	if (!opts)
628		return ERR_PTR(-ENOMEM);
629
630	opts->func_inst.free_func_inst = phonet_free_inst;
631	opts->net = gphonet_setup_default();
632	if (IS_ERR(opts->net)) {
633		struct net_device *net = opts->net;
634		kfree(opts);
635		return ERR_CAST(net);
636	}
637
638	config_group_init_type_name(&opts->func_inst.group, "",
639			&phonet_func_type);
640
641	return &opts->func_inst;
642}
643
644static void phonet_free(struct usb_function *f)
645{
646	struct f_phonet *phonet;
647
648	phonet = func_to_pn(f);
649	kfree(phonet);
650}
651
652static void pn_unbind(struct usb_configuration *c, struct usb_function *f)
653{
654	struct f_phonet *fp = func_to_pn(f);
655	int i;
656
657	/* We are already disconnected */
658	if (fp->in_req)
659		usb_ep_free_request(fp->in_ep, fp->in_req);
660	for (i = 0; i < phonet_rxq_size; i++)
661		if (fp->out_reqv[i])
662			usb_ep_free_request(fp->out_ep, fp->out_reqv[i]);
663
664	usb_free_all_descriptors(f);
665}
666
667static struct usb_function *phonet_alloc(struct usb_function_instance *fi)
668{
669	struct f_phonet *fp;
670	struct f_phonet_opts *opts;
671
672	fp = kzalloc(struct_size(fp, out_reqv, phonet_rxq_size), GFP_KERNEL);
673	if (!fp)
674		return ERR_PTR(-ENOMEM);
675
676	opts = container_of(fi, struct f_phonet_opts, func_inst);
677
678	fp->dev = opts->net;
679	fp->function.name = "phonet";
680	fp->function.bind = pn_bind;
681	fp->function.unbind = pn_unbind;
682	fp->function.set_alt = pn_set_alt;
683	fp->function.get_alt = pn_get_alt;
684	fp->function.disable = pn_disconnect;
685	fp->function.free_func = phonet_free;
686	spin_lock_init(&fp->rx.lock);
687
688	return &fp->function;
689}
690
691struct net_device *gphonet_setup_default(void)
692{
693	struct net_device *dev;
694	struct phonet_port *port;
695
696	/* Create net device */
697	dev = alloc_netdev(sizeof(*port), "upnlink%d", NET_NAME_UNKNOWN,
698			   pn_net_setup);
699	if (!dev)
700		return ERR_PTR(-ENOMEM);
701
702	port = netdev_priv(dev);
703	spin_lock_init(&port->lock);
704	netif_carrier_off(dev);
705
706	return dev;
707}
708
709void gphonet_set_gadget(struct net_device *net, struct usb_gadget *g)
710{
711	SET_NETDEV_DEV(net, &g->dev);
712}
713
714int gphonet_register_netdev(struct net_device *net)
715{
716	int status;
717
718	status = register_netdev(net);
719	if (status)
720		free_netdev(net);
721
722	return status;
723}
724
725void gphonet_cleanup(struct net_device *dev)
726{
727	unregister_netdev(dev);
728}
729
730DECLARE_USB_FUNCTION_INIT(phonet, phonet_alloc_inst, phonet_alloc);
731MODULE_AUTHOR("R��mi Denis-Courmont");
732MODULE_LICENSE("GPL");
733