1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for USB ethernet port of Conexant CX82310-based ADSL routers
4 * Copyright (C) 2010 by Ondrej Zary
5 * some parts inspired by the cxacru driver
6 */
7
8#include <linux/module.h>
9#include <linux/netdevice.h>
10#include <linux/etherdevice.h>
11#include <linux/ethtool.h>
12#include <linux/workqueue.h>
13#include <linux/mii.h>
14#include <linux/usb.h>
15#include <linux/usb/usbnet.h>
16
17enum cx82310_cmd {
18	CMD_START		= 0x84,	/* no effect? */
19	CMD_STOP		= 0x85,	/* no effect? */
20	CMD_GET_STATUS		= 0x90,	/* returns nothing? */
21	CMD_GET_MAC_ADDR	= 0x91,	/* read MAC address */
22	CMD_GET_LINK_STATUS	= 0x92,	/* not useful, link is always up */
23	CMD_ETHERNET_MODE	= 0x99,	/* unknown, needed during init */
24};
25
26enum cx82310_status {
27	STATUS_UNDEFINED,
28	STATUS_SUCCESS,
29	STATUS_ERROR,
30	STATUS_UNSUPPORTED,
31	STATUS_UNIMPLEMENTED,
32	STATUS_PARAMETER_ERROR,
33	STATUS_DBG_LOOPBACK,
34};
35
36#define CMD_PACKET_SIZE	64
37#define CMD_TIMEOUT	100
38#define CMD_REPLY_RETRY 5
39
40#define CX82310_MTU	1514
41#define CMD_EP		0x01
42
43struct cx82310_priv {
44	struct work_struct reenable_work;
45	struct usbnet *dev;
46};
47
48/*
49 * execute control command
50 *  - optionally send some data (command parameters)
51 *  - optionally wait for the reply
52 *  - optionally read some data from the reply
53 */
54static int cx82310_cmd(struct usbnet *dev, enum cx82310_cmd cmd, bool reply,
55		       u8 *wdata, int wlen, u8 *rdata, int rlen)
56{
57	int actual_len, retries, ret;
58	struct usb_device *udev = dev->udev;
59	u8 *buf = kzalloc(CMD_PACKET_SIZE, GFP_KERNEL);
60
61	if (!buf)
62		return -ENOMEM;
63
64	/* create command packet */
65	buf[0] = cmd;
66	if (wdata)
67		memcpy(buf + 4, wdata, min_t(int, wlen, CMD_PACKET_SIZE - 4));
68
69	/* send command packet */
70	ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, CMD_EP), buf,
71			   CMD_PACKET_SIZE, &actual_len, CMD_TIMEOUT);
72	if (ret < 0) {
73		if (cmd != CMD_GET_LINK_STATUS)
74			netdev_err(dev->net, "send command %#x: error %d\n",
75				   cmd, ret);
76		goto end;
77	}
78
79	if (reply) {
80		/* wait for reply, retry if it's empty */
81		for (retries = 0; retries < CMD_REPLY_RETRY; retries++) {
82			ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, CMD_EP),
83					   buf, CMD_PACKET_SIZE, &actual_len,
84					   CMD_TIMEOUT);
85			if (ret < 0) {
86				if (cmd != CMD_GET_LINK_STATUS)
87					netdev_err(dev->net, "reply receive error %d\n",
88						   ret);
89				goto end;
90			}
91			if (actual_len > 0)
92				break;
93		}
94		if (actual_len == 0) {
95			netdev_err(dev->net, "no reply to command %#x\n", cmd);
96			ret = -EIO;
97			goto end;
98		}
99		if (buf[0] != cmd) {
100			netdev_err(dev->net, "got reply to command %#x, expected: %#x\n",
101				   buf[0], cmd);
102			ret = -EIO;
103			goto end;
104		}
105		if (buf[1] != STATUS_SUCCESS) {
106			netdev_err(dev->net, "command %#x failed: %#x\n", cmd,
107				   buf[1]);
108			ret = -EIO;
109			goto end;
110		}
111		if (rdata)
112			memcpy(rdata, buf + 4,
113			       min_t(int, rlen, CMD_PACKET_SIZE - 4));
114	}
115end:
116	kfree(buf);
117	return ret;
118}
119
120static int cx82310_enable_ethernet(struct usbnet *dev)
121{
122	int ret = cx82310_cmd(dev, CMD_ETHERNET_MODE, true, "\x01", 1, NULL, 0);
123
124	if (ret)
125		netdev_err(dev->net, "unable to enable ethernet mode: %d\n",
126			   ret);
127	return ret;
128}
129
130static void cx82310_reenable_work(struct work_struct *work)
131{
132	struct cx82310_priv *priv = container_of(work, struct cx82310_priv,
133						 reenable_work);
134	cx82310_enable_ethernet(priv->dev);
135}
136
137#define partial_len	data[0]		/* length of partial packet data */
138#define partial_rem	data[1]		/* remaining (missing) data length */
139#define partial_data	data[2]		/* partial packet data */
140
141static int cx82310_bind(struct usbnet *dev, struct usb_interface *intf)
142{
143	int ret;
144	char buf[15];
145	struct usb_device *udev = dev->udev;
146	u8 link[3];
147	int timeout = 50;
148	struct cx82310_priv *priv;
149
150	/* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
151	if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
152	    && strcmp(buf, "USB NET CARD")) {
153		dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
154		return -ENODEV;
155	}
156
157	ret = usbnet_get_endpoints(dev, intf);
158	if (ret)
159		return ret;
160
161	/*
162	 * this must not include ethernet header as the device can send partial
163	 * packets with no header (and sometimes even empty URBs)
164	 */
165	dev->net->hard_header_len = 0;
166	/* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
167	dev->hard_mtu = CX82310_MTU + 2;
168	/* we can receive URBs up to 4KB from the device */
169	dev->rx_urb_size = 4096;
170
171	dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
172	if (!dev->partial_data)
173		return -ENOMEM;
174
175	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
176	if (!priv) {
177		ret = -ENOMEM;
178		goto err_partial;
179	}
180	dev->driver_priv = priv;
181	INIT_WORK(&priv->reenable_work, cx82310_reenable_work);
182	priv->dev = dev;
183
184	/* wait for firmware to become ready (indicated by the link being up) */
185	while (--timeout) {
186		ret = cx82310_cmd(dev, CMD_GET_LINK_STATUS, true, NULL, 0,
187				  link, sizeof(link));
188		/* the command can time out during boot - it's not an error */
189		if (!ret && link[0] == 1 && link[2] == 1)
190			break;
191		msleep(500);
192	}
193	if (!timeout) {
194		netdev_err(dev->net, "firmware not ready in time\n");
195		ret = -ETIMEDOUT;
196		goto err;
197	}
198
199	/* enable ethernet mode (?) */
200	ret = cx82310_enable_ethernet(dev);
201	if (ret)
202		goto err;
203
204	/* get the MAC address */
205	ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0,
206			  dev->net->dev_addr, ETH_ALEN);
207	if (ret) {
208		netdev_err(dev->net, "unable to read MAC address: %d\n", ret);
209		goto err;
210	}
211
212	/* start (does not seem to have any effect?) */
213	ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
214	if (ret)
215		goto err;
216
217	return 0;
218err:
219	kfree(dev->driver_priv);
220err_partial:
221	kfree((void *)dev->partial_data);
222	return ret;
223}
224
225static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
226{
227	struct cx82310_priv *priv = dev->driver_priv;
228
229	kfree((void *)dev->partial_data);
230	cancel_work_sync(&priv->reenable_work);
231	kfree(dev->driver_priv);
232}
233
234/*
235 * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
236 * packet length at the beginning.
237 * The last packet might be incomplete (when it crosses the 4KB URB size),
238 * continuing in the next skb (without any headers).
239 * If a packet has odd length, there is one extra byte at the end (before next
240 * packet or at the end of the URB).
241 */
242static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
243{
244	int len;
245	struct sk_buff *skb2;
246	struct cx82310_priv *priv = dev->driver_priv;
247
248	/*
249	 * If the last skb ended with an incomplete packet, this skb contains
250	 * end of that packet at the beginning.
251	 */
252	if (dev->partial_rem) {
253		len = dev->partial_len + dev->partial_rem;
254		skb2 = alloc_skb(len, GFP_ATOMIC);
255		if (!skb2)
256			return 0;
257		skb_put(skb2, len);
258		memcpy(skb2->data, (void *)dev->partial_data,
259		       dev->partial_len);
260		memcpy(skb2->data + dev->partial_len, skb->data,
261		       dev->partial_rem);
262		usbnet_skb_return(dev, skb2);
263		skb_pull(skb, (dev->partial_rem + 1) & ~1);
264		dev->partial_rem = 0;
265		if (skb->len < 2)
266			return 1;
267	}
268
269	/* a skb can contain multiple packets */
270	while (skb->len > 1) {
271		/* first two bytes are packet length */
272		len = skb->data[0] | (skb->data[1] << 8);
273		skb_pull(skb, 2);
274
275		/* if last packet in the skb, let usbnet to process it */
276		if (len == skb->len || len + 1 == skb->len) {
277			skb_trim(skb, len);
278			break;
279		}
280
281		if (len == 0xffff) {
282			netdev_info(dev->net, "router was rebooted, re-enabling ethernet mode");
283			schedule_work(&priv->reenable_work);
284		} else if (len > CX82310_MTU) {
285			netdev_err(dev->net, "RX packet too long: %d B\n", len);
286			return 0;
287		}
288
289		/* incomplete packet, save it for the next skb */
290		if (len > skb->len) {
291			dev->partial_len = skb->len;
292			dev->partial_rem = len - skb->len;
293			memcpy((void *)dev->partial_data, skb->data,
294			       dev->partial_len);
295			skb_pull(skb, skb->len);
296			break;
297		}
298
299		skb2 = alloc_skb(len, GFP_ATOMIC);
300		if (!skb2)
301			return 0;
302		skb_put(skb2, len);
303		memcpy(skb2->data, skb->data, len);
304		/* process the packet */
305		usbnet_skb_return(dev, skb2);
306
307		skb_pull(skb, (len + 1) & ~1);
308	}
309
310	/* let usbnet process the last packet */
311	return 1;
312}
313
314/* TX is easy, just add 2 bytes of length at the beginning */
315static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
316				       gfp_t flags)
317{
318	int len = skb->len;
319
320	if (skb_cow_head(skb, 2)) {
321		dev_kfree_skb_any(skb);
322		return NULL;
323	}
324	skb_push(skb, 2);
325
326	skb->data[0] = len;
327	skb->data[1] = len >> 8;
328
329	return skb;
330}
331
332
333static const struct driver_info	cx82310_info = {
334	.description	= "Conexant CX82310 USB ethernet",
335	.flags		= FLAG_ETHER,
336	.bind		= cx82310_bind,
337	.unbind		= cx82310_unbind,
338	.rx_fixup	= cx82310_rx_fixup,
339	.tx_fixup	= cx82310_tx_fixup,
340};
341
342#define USB_DEVICE_CLASS(vend, prod, cl, sc, pr) \
343	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
344		       USB_DEVICE_ID_MATCH_DEV_INFO, \
345	.idVendor = (vend), \
346	.idProduct = (prod), \
347	.bDeviceClass = (cl), \
348	.bDeviceSubClass = (sc), \
349	.bDeviceProtocol = (pr)
350
351static const struct usb_device_id products[] = {
352	{
353		USB_DEVICE_CLASS(0x0572, 0xcb01, 0xff, 0, 0),
354		.driver_info = (unsigned long) &cx82310_info
355	},
356	{ },
357};
358MODULE_DEVICE_TABLE(usb, products);
359
360static struct usb_driver cx82310_driver = {
361	.name		= "cx82310_eth",
362	.id_table	= products,
363	.probe		= usbnet_probe,
364	.disconnect	= usbnet_disconnect,
365	.suspend	= usbnet_suspend,
366	.resume		= usbnet_resume,
367	.disable_hub_initiated_lpm = 1,
368};
369
370module_usb_driver(cx82310_driver);
371
372MODULE_AUTHOR("Ondrej Zary");
373MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
374MODULE_LICENSE("GPL");
375