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	u8 addr[ETH_ALEN];
150
151	/* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
152	if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
153	    && strcmp(buf, "USB NET CARD")) {
154		dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
155		return -ENODEV;
156	}
157
158	ret = usbnet_get_endpoints(dev, intf);
159	if (ret)
160		return ret;
161
162	/*
163	 * this must not include ethernet header as the device can send partial
164	 * packets with no header (and sometimes even empty URBs)
165	 */
166	dev->net->hard_header_len = 0;
167	/* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
168	dev->hard_mtu = CX82310_MTU + 2;
169	/* we can receive URBs up to 4KB from the device */
170	dev->rx_urb_size = 4096;
171
172	dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
173	if (!dev->partial_data)
174		return -ENOMEM;
175
176	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
177	if (!priv) {
178		ret = -ENOMEM;
179		goto err_partial;
180	}
181	dev->driver_priv = priv;
182	INIT_WORK(&priv->reenable_work, cx82310_reenable_work);
183	priv->dev = dev;
184
185	/* wait for firmware to become ready (indicated by the link being up) */
186	while (--timeout) {
187		ret = cx82310_cmd(dev, CMD_GET_LINK_STATUS, true, NULL, 0,
188				  link, sizeof(link));
189		/* the command can time out during boot - it's not an error */
190		if (!ret && link[0] == 1 && link[2] == 1)
191			break;
192		msleep(500);
193	}
194	if (!timeout) {
195		netdev_err(dev->net, "firmware not ready in time\n");
196		ret = -ETIMEDOUT;
197		goto err;
198	}
199
200	/* enable ethernet mode (?) */
201	ret = cx82310_enable_ethernet(dev);
202	if (ret)
203		goto err;
204
205	/* get the MAC address */
206	ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0, addr, ETH_ALEN);
207	if (ret) {
208		netdev_err(dev->net, "unable to read MAC address: %d\n", ret);
209		goto err;
210	}
211	eth_hw_addr_set(dev->net, addr);
212
213	/* start (does not seem to have any effect?) */
214	ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
215	if (ret)
216		goto err;
217
218	return 0;
219err:
220	kfree(dev->driver_priv);
221err_partial:
222	kfree((void *)dev->partial_data);
223	return ret;
224}
225
226static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
227{
228	struct cx82310_priv *priv = dev->driver_priv;
229
230	kfree((void *)dev->partial_data);
231	cancel_work_sync(&priv->reenable_work);
232	kfree(dev->driver_priv);
233}
234
235/*
236 * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
237 * packet length at the beginning.
238 * The last packet might be incomplete (when it crosses the 4KB URB size),
239 * continuing in the next skb (without any headers).
240 * If a packet has odd length, there is one extra byte at the end (before next
241 * packet or at the end of the URB).
242 */
243static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
244{
245	int len;
246	struct sk_buff *skb2;
247	struct cx82310_priv *priv = dev->driver_priv;
248
249	/*
250	 * If the last skb ended with an incomplete packet, this skb contains
251	 * end of that packet at the beginning.
252	 */
253	if (dev->partial_rem) {
254		len = dev->partial_len + dev->partial_rem;
255		skb2 = alloc_skb(len, GFP_ATOMIC);
256		if (!skb2)
257			return 0;
258		skb_put(skb2, len);
259		memcpy(skb2->data, (void *)dev->partial_data,
260		       dev->partial_len);
261		memcpy(skb2->data + dev->partial_len, skb->data,
262		       dev->partial_rem);
263		usbnet_skb_return(dev, skb2);
264		skb_pull(skb, (dev->partial_rem + 1) & ~1);
265		dev->partial_rem = 0;
266		if (skb->len < 2)
267			return 1;
268	}
269
270	/* a skb can contain multiple packets */
271	while (skb->len > 1) {
272		/* first two bytes are packet length */
273		len = skb->data[0] | (skb->data[1] << 8);
274		skb_pull(skb, 2);
275
276		/* if last packet in the skb, let usbnet to process it */
277		if (len == skb->len || len + 1 == skb->len) {
278			skb_trim(skb, len);
279			break;
280		}
281
282		if (len == 0xffff) {
283			netdev_info(dev->net, "router was rebooted, re-enabling ethernet mode");
284			schedule_work(&priv->reenable_work);
285		} else if (len > CX82310_MTU) {
286			netdev_err(dev->net, "RX packet too long: %d B\n", len);
287			return 0;
288		}
289
290		/* incomplete packet, save it for the next skb */
291		if (len > skb->len) {
292			dev->partial_len = skb->len;
293			dev->partial_rem = len - skb->len;
294			memcpy((void *)dev->partial_data, skb->data,
295			       dev->partial_len);
296			skb_pull(skb, skb->len);
297			break;
298		}
299
300		skb2 = alloc_skb(len, GFP_ATOMIC);
301		if (!skb2)
302			return 0;
303		skb_put(skb2, len);
304		memcpy(skb2->data, skb->data, len);
305		/* process the packet */
306		usbnet_skb_return(dev, skb2);
307
308		skb_pull(skb, (len + 1) & ~1);
309	}
310
311	/* let usbnet process the last packet */
312	return 1;
313}
314
315/* TX is easy, just add 2 bytes of length at the beginning */
316static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
317				       gfp_t flags)
318{
319	int len = skb->len;
320
321	if (skb_cow_head(skb, 2)) {
322		dev_kfree_skb_any(skb);
323		return NULL;
324	}
325	skb_push(skb, 2);
326
327	skb->data[0] = len;
328	skb->data[1] = len >> 8;
329
330	return skb;
331}
332
333
334static const struct driver_info	cx82310_info = {
335	.description	= "Conexant CX82310 USB ethernet",
336	.flags		= FLAG_ETHER,
337	.bind		= cx82310_bind,
338	.unbind		= cx82310_unbind,
339	.rx_fixup	= cx82310_rx_fixup,
340	.tx_fixup	= cx82310_tx_fixup,
341};
342
343#define USB_DEVICE_CLASS(vend, prod, cl, sc, pr) \
344	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
345		       USB_DEVICE_ID_MATCH_DEV_INFO, \
346	.idVendor = (vend), \
347	.idProduct = (prod), \
348	.bDeviceClass = (cl), \
349	.bDeviceSubClass = (sc), \
350	.bDeviceProtocol = (pr)
351
352static const struct usb_device_id products[] = {
353	{
354		USB_DEVICE_CLASS(0x0572, 0xcb01, 0xff, 0, 0),
355		.driver_info = (unsigned long) &cx82310_info
356	},
357	{ },
358};
359MODULE_DEVICE_TABLE(usb, products);
360
361static struct usb_driver cx82310_driver = {
362	.name		= "cx82310_eth",
363	.id_table	= products,
364	.probe		= usbnet_probe,
365	.disconnect	= usbnet_disconnect,
366	.suspend	= usbnet_suspend,
367	.resume		= usbnet_resume,
368	.disable_hub_initiated_lpm = 1,
369};
370
371module_usb_driver(cx82310_driver);
372
373MODULE_AUTHOR("Ondrej Zary");
374MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
375MODULE_LICENSE("GPL");
376