1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * phonet.c -- USB CDC Phonet host driver
4 *
5 * Copyright (C) 2008-2009 Nokia Corporation. All rights reserved.
6 *
7 * Author: Rémi Denis-Courmont
8 */
9
10#include <linux/kernel.h>
11#include <linux/mm.h>
12#include <linux/module.h>
13#include <linux/gfp.h>
14#include <linux/usb.h>
15#include <linux/usb/cdc.h>
16#include <linux/netdevice.h>
17#include <linux/if_arp.h>
18#include <linux/if_phonet.h>
19#include <linux/phonet.h>
20
21#define PN_MEDIA_USB	0x1B
22
23static const unsigned rxq_size = 17;
24
25struct usbpn_dev {
26	struct net_device	*dev;
27
28	struct usb_interface	*intf, *data_intf;
29	struct usb_device	*usb;
30	unsigned int		tx_pipe, rx_pipe;
31	u8 active_setting;
32	u8 disconnected;
33
34	unsigned		tx_queue;
35	spinlock_t		tx_lock;
36
37	spinlock_t		rx_lock;
38	struct sk_buff		*rx_skb;
39	struct urb		*urbs[];
40};
41
42static void tx_complete(struct urb *req);
43static void rx_complete(struct urb *req);
44
45/*
46 * Network device callbacks
47 */
48static netdev_tx_t usbpn_xmit(struct sk_buff *skb, struct net_device *dev)
49{
50	struct usbpn_dev *pnd = netdev_priv(dev);
51	struct urb *req = NULL;
52	unsigned long flags;
53	int err;
54
55	if (skb->protocol != htons(ETH_P_PHONET))
56		goto drop;
57
58	req = usb_alloc_urb(0, GFP_ATOMIC);
59	if (!req)
60		goto drop;
61	usb_fill_bulk_urb(req, pnd->usb, pnd->tx_pipe, skb->data, skb->len,
62				tx_complete, skb);
63	req->transfer_flags = URB_ZERO_PACKET;
64	err = usb_submit_urb(req, GFP_ATOMIC);
65	if (err) {
66		usb_free_urb(req);
67		goto drop;
68	}
69
70	spin_lock_irqsave(&pnd->tx_lock, flags);
71	pnd->tx_queue++;
72	if (pnd->tx_queue >= dev->tx_queue_len)
73		netif_stop_queue(dev);
74	spin_unlock_irqrestore(&pnd->tx_lock, flags);
75	return NETDEV_TX_OK;
76
77drop:
78	dev_kfree_skb(skb);
79	dev->stats.tx_dropped++;
80	return NETDEV_TX_OK;
81}
82
83static void tx_complete(struct urb *req)
84{
85	struct sk_buff *skb = req->context;
86	struct net_device *dev = skb->dev;
87	struct usbpn_dev *pnd = netdev_priv(dev);
88	int status = req->status;
89	unsigned long flags;
90
91	switch (status) {
92	case 0:
93		dev->stats.tx_bytes += skb->len;
94		break;
95
96	case -ENOENT:
97	case -ECONNRESET:
98	case -ESHUTDOWN:
99		dev->stats.tx_aborted_errors++;
100		fallthrough;
101	default:
102		dev->stats.tx_errors++;
103		dev_dbg(&dev->dev, "TX error (%d)\n", status);
104	}
105	dev->stats.tx_packets++;
106
107	spin_lock_irqsave(&pnd->tx_lock, flags);
108	pnd->tx_queue--;
109	netif_wake_queue(dev);
110	spin_unlock_irqrestore(&pnd->tx_lock, flags);
111
112	dev_kfree_skb_any(skb);
113	usb_free_urb(req);
114}
115
116static int rx_submit(struct usbpn_dev *pnd, struct urb *req, gfp_t gfp_flags)
117{
118	struct net_device *dev = pnd->dev;
119	struct page *page;
120	int err;
121
122	page = __dev_alloc_page(gfp_flags | __GFP_NOMEMALLOC);
123	if (!page)
124		return -ENOMEM;
125
126	usb_fill_bulk_urb(req, pnd->usb, pnd->rx_pipe, page_address(page),
127				PAGE_SIZE, rx_complete, dev);
128	req->transfer_flags = 0;
129	err = usb_submit_urb(req, gfp_flags);
130	if (unlikely(err)) {
131		dev_dbg(&dev->dev, "RX submit error (%d)\n", err);
132		put_page(page);
133	}
134	return err;
135}
136
137static void rx_complete(struct urb *req)
138{
139	struct net_device *dev = req->context;
140	struct usbpn_dev *pnd = netdev_priv(dev);
141	struct page *page = virt_to_page(req->transfer_buffer);
142	struct sk_buff *skb;
143	unsigned long flags;
144	int status = req->status;
145
146	switch (status) {
147	case 0:
148		spin_lock_irqsave(&pnd->rx_lock, flags);
149		skb = pnd->rx_skb;
150		if (!skb) {
151			skb = pnd->rx_skb = netdev_alloc_skb(dev, 12);
152			if (likely(skb)) {
153				/* Can't use pskb_pull() on page in IRQ */
154				skb_put_data(skb, page_address(page), 1);
155				skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
156						page, 1, req->actual_length,
157						PAGE_SIZE);
158				page = NULL;
159			}
160		} else {
161			skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
162					page, 0, req->actual_length,
163					PAGE_SIZE);
164			page = NULL;
165		}
166		if (req->actual_length < PAGE_SIZE)
167			pnd->rx_skb = NULL; /* Last fragment */
168		else
169			skb = NULL;
170		spin_unlock_irqrestore(&pnd->rx_lock, flags);
171		if (skb) {
172			skb->protocol = htons(ETH_P_PHONET);
173			skb_reset_mac_header(skb);
174			__skb_pull(skb, 1);
175			skb->dev = dev;
176			dev->stats.rx_packets++;
177			dev->stats.rx_bytes += skb->len;
178
179			netif_rx(skb);
180		}
181		goto resubmit;
182
183	case -ENOENT:
184	case -ECONNRESET:
185	case -ESHUTDOWN:
186		req = NULL;
187		break;
188
189	case -EOVERFLOW:
190		dev->stats.rx_over_errors++;
191		dev_dbg(&dev->dev, "RX overflow\n");
192		break;
193
194	case -EILSEQ:
195		dev->stats.rx_crc_errors++;
196		break;
197	}
198
199	dev->stats.rx_errors++;
200resubmit:
201	if (page)
202		put_page(page);
203	if (req)
204		rx_submit(pnd, req, GFP_ATOMIC);
205}
206
207static int usbpn_close(struct net_device *dev);
208
209static int usbpn_open(struct net_device *dev)
210{
211	struct usbpn_dev *pnd = netdev_priv(dev);
212	int err;
213	unsigned i;
214	unsigned num = pnd->data_intf->cur_altsetting->desc.bInterfaceNumber;
215
216	err = usb_set_interface(pnd->usb, num, pnd->active_setting);
217	if (err)
218		return err;
219
220	for (i = 0; i < rxq_size; i++) {
221		struct urb *req = usb_alloc_urb(0, GFP_KERNEL);
222
223		if (!req || rx_submit(pnd, req, GFP_KERNEL)) {
224			usb_free_urb(req);
225			usbpn_close(dev);
226			return -ENOMEM;
227		}
228		pnd->urbs[i] = req;
229	}
230
231	netif_wake_queue(dev);
232	return 0;
233}
234
235static int usbpn_close(struct net_device *dev)
236{
237	struct usbpn_dev *pnd = netdev_priv(dev);
238	unsigned i;
239	unsigned num = pnd->data_intf->cur_altsetting->desc.bInterfaceNumber;
240
241	netif_stop_queue(dev);
242
243	for (i = 0; i < rxq_size; i++) {
244		struct urb *req = pnd->urbs[i];
245
246		if (!req)
247			continue;
248		usb_kill_urb(req);
249		usb_free_urb(req);
250		pnd->urbs[i] = NULL;
251	}
252
253	return usb_set_interface(pnd->usb, num, !pnd->active_setting);
254}
255
256static int usbpn_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
257{
258	struct if_phonet_req *req = (struct if_phonet_req *)ifr;
259
260	switch (cmd) {
261	case SIOCPNGAUTOCONF:
262		req->ifr_phonet_autoconf.device = PN_DEV_PC;
263		return 0;
264	}
265	return -ENOIOCTLCMD;
266}
267
268static const struct net_device_ops usbpn_ops = {
269	.ndo_open	= usbpn_open,
270	.ndo_stop	= usbpn_close,
271	.ndo_start_xmit = usbpn_xmit,
272	.ndo_do_ioctl	= usbpn_ioctl,
273};
274
275static void usbpn_setup(struct net_device *dev)
276{
277	dev->features		= 0;
278	dev->netdev_ops		= &usbpn_ops,
279	dev->header_ops		= &phonet_header_ops;
280	dev->type		= ARPHRD_PHONET;
281	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
282	dev->mtu		= PHONET_MAX_MTU;
283	dev->min_mtu		= PHONET_MIN_MTU;
284	dev->max_mtu		= PHONET_MAX_MTU;
285	dev->hard_header_len	= 1;
286	dev->dev_addr[0]	= PN_MEDIA_USB;
287	dev->addr_len		= 1;
288	dev->tx_queue_len	= 3;
289
290	dev->needs_free_netdev	= true;
291}
292
293/*
294 * USB driver callbacks
295 */
296static const struct usb_device_id usbpn_ids[] = {
297	{
298		.match_flags = USB_DEVICE_ID_MATCH_VENDOR
299			| USB_DEVICE_ID_MATCH_INT_CLASS
300			| USB_DEVICE_ID_MATCH_INT_SUBCLASS,
301		.idVendor = 0x0421, /* Nokia */
302		.bInterfaceClass = USB_CLASS_COMM,
303		.bInterfaceSubClass = 0xFE,
304	},
305	{ },
306};
307
308MODULE_DEVICE_TABLE(usb, usbpn_ids);
309
310static struct usb_driver usbpn_driver;
311
312static int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
313{
314	static const char ifname[] = "usbpn%d";
315	const struct usb_cdc_union_desc *union_header = NULL;
316	const struct usb_host_interface *data_desc;
317	struct usb_interface *data_intf;
318	struct usb_device *usbdev = interface_to_usbdev(intf);
319	struct net_device *dev;
320	struct usbpn_dev *pnd;
321	u8 *data;
322	int phonet = 0;
323	int len, err;
324	struct usb_cdc_parsed_header hdr;
325
326	data = intf->altsetting->extra;
327	len = intf->altsetting->extralen;
328	cdc_parse_cdc_header(&hdr, intf, data, len);
329	union_header = hdr.usb_cdc_union_desc;
330	phonet = hdr.phonet_magic_present;
331
332	if (!union_header || !phonet)
333		return -EINVAL;
334
335	data_intf = usb_ifnum_to_if(usbdev, union_header->bSlaveInterface0);
336	if (data_intf == NULL)
337		return -ENODEV;
338	/* Data interface has one inactive and one active setting */
339	if (data_intf->num_altsetting != 2)
340		return -EINVAL;
341	if (data_intf->altsetting[0].desc.bNumEndpoints == 0 &&
342	    data_intf->altsetting[1].desc.bNumEndpoints == 2)
343		data_desc = data_intf->altsetting + 1;
344	else
345	if (data_intf->altsetting[0].desc.bNumEndpoints == 2 &&
346	    data_intf->altsetting[1].desc.bNumEndpoints == 0)
347		data_desc = data_intf->altsetting;
348	else
349		return -EINVAL;
350
351	dev = alloc_netdev(struct_size(pnd, urbs, rxq_size), ifname,
352			   NET_NAME_UNKNOWN, usbpn_setup);
353	if (!dev)
354		return -ENOMEM;
355
356	pnd = netdev_priv(dev);
357	SET_NETDEV_DEV(dev, &intf->dev);
358
359	pnd->dev = dev;
360	pnd->usb = usbdev;
361	pnd->intf = intf;
362	pnd->data_intf = data_intf;
363	spin_lock_init(&pnd->tx_lock);
364	spin_lock_init(&pnd->rx_lock);
365	/* Endpoints */
366	if (usb_pipein(data_desc->endpoint[0].desc.bEndpointAddress)) {
367		pnd->rx_pipe = usb_rcvbulkpipe(usbdev,
368			data_desc->endpoint[0].desc.bEndpointAddress);
369		pnd->tx_pipe = usb_sndbulkpipe(usbdev,
370			data_desc->endpoint[1].desc.bEndpointAddress);
371	} else {
372		pnd->rx_pipe = usb_rcvbulkpipe(usbdev,
373			data_desc->endpoint[1].desc.bEndpointAddress);
374		pnd->tx_pipe = usb_sndbulkpipe(usbdev,
375			data_desc->endpoint[0].desc.bEndpointAddress);
376	}
377	pnd->active_setting = data_desc - data_intf->altsetting;
378
379	err = usb_driver_claim_interface(&usbpn_driver, data_intf, pnd);
380	if (err)
381		goto out;
382
383	/* Force inactive mode until the network device is brought UP */
384	usb_set_interface(usbdev, union_header->bSlaveInterface0,
385				!pnd->active_setting);
386	usb_set_intfdata(intf, pnd);
387
388	err = register_netdev(dev);
389	if (err) {
390		/* Set disconnected flag so that disconnect() returns early. */
391		pnd->disconnected = 1;
392		usb_driver_release_interface(&usbpn_driver, data_intf);
393		goto out;
394	}
395
396	dev_dbg(&dev->dev, "USB CDC Phonet device found\n");
397	return 0;
398
399out:
400	usb_set_intfdata(intf, NULL);
401	free_netdev(dev);
402	return err;
403}
404
405static void usbpn_disconnect(struct usb_interface *intf)
406{
407	struct usbpn_dev *pnd = usb_get_intfdata(intf);
408
409	if (pnd->disconnected)
410		return;
411
412	pnd->disconnected = 1;
413	usb_driver_release_interface(&usbpn_driver,
414			(pnd->intf == intf) ? pnd->data_intf : pnd->intf);
415	unregister_netdev(pnd->dev);
416}
417
418static struct usb_driver usbpn_driver = {
419	.name =		"cdc_phonet",
420	.probe =	usbpn_probe,
421	.disconnect =	usbpn_disconnect,
422	.id_table =	usbpn_ids,
423	.disable_hub_initiated_lpm = 1,
424};
425
426module_usb_driver(usbpn_driver);
427
428MODULE_AUTHOR("Remi Denis-Courmont");
429MODULE_DESCRIPTION("USB CDC Phonet host interface");
430MODULE_LICENSE("GPL");
431