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