Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Net1080 based USB host-to-host cables
 * Copyright (C) 2000-2005 by David Brownell
 */

// #define	DEBUG			// error path messages, extra info
// #define	VERBOSE			// more; success messages

#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb/usbnet.h>
#include <linux/slab.h>

#include <asm/unaligned.h>


/*
 * Netchip 1080 driver ... http://www.netchip.com
 * (Sept 2004:  End-of-life announcement has been sent.)
 * Used in (some) LapLink cables
 */

#define frame_errors	data[1]

/*
 * NetChip framing of ethernet packets, supporting additional error
 * checks for links that may drop bulk packets from inside messages.
 * Odd USB length == always short read for last usb packet.
 *	- nc_header
 *	- Ethernet header (14 bytes)
 *	- payload
 *	- (optional padding byte, if needed so length becomes odd)
 *	- nc_trailer
 *
 * This framing is to be avoided for non-NetChip devices.
 */

struct nc_header {		// packed:
	__le16	hdr_len;		// sizeof nc_header (LE, all)
	__le16	packet_len;		// payload size (including ethhdr)
	__le16	packet_id;		// detects dropped packets
#define MIN_HEADER	6

	// all else is optional, and must start with:
	// __le16	vendorId;	// from usb-if
	// __le16	productId;
} __packed;

#define	PAD_BYTE	((unsigned char)0xAC)

struct nc_trailer {
	__le16	packet_id;
} __packed;

// packets may use FLAG_FRAMING_NC and optional pad
#define FRAMED_SIZE(mtu) (sizeof (struct nc_header) \
				+ sizeof (struct ethhdr) \
				+ (mtu) \
				+ 1 \
				+ sizeof (struct nc_trailer))

#define MIN_FRAMED	FRAMED_SIZE(0)

/* packets _could_ be up to 64KB... */
#define NC_MAX_PACKET	32767


/*
 * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
 * before the hardware drops it.  If that's done, the driver will need to
 * frame network packets to guard against the dropped USB packets.  The win32
 * driver sets this for both sides of the link.
 */
#define	NC_READ_TTL_MS	((u8)255)	// ms

/*
 * We ignore most registers and EEPROM contents.
 */
#define	REG_USBCTL	((u8)0x04)
#define REG_TTL		((u8)0x10)
#define REG_STATUS	((u8)0x11)

/*
 * Vendor specific requests to read/write data
 */
#define	REQUEST_REGISTER	((u8)0x10)
#define	REQUEST_EEPROM		((u8)0x11)

static int
nc_vendor_read(struct usbnet *dev, u8 req, u8 regnum, u16 *retval_ptr)
{
	int status = usbnet_read_cmd(dev, req,
				     USB_DIR_IN | USB_TYPE_VENDOR |
				     USB_RECIP_DEVICE,
				     0, regnum, retval_ptr,
				     sizeof *retval_ptr);
	if (status > 0)
		status = 0;
	if (!status)
		le16_to_cpus(retval_ptr);
	return status;
}

static inline int
nc_register_read(struct usbnet *dev, u8 regnum, u16 *retval_ptr)
{
	return nc_vendor_read(dev, REQUEST_REGISTER, regnum, retval_ptr);
}

static void
nc_vendor_write(struct usbnet *dev, u8 req, u8 regnum, u16 value)
{
	usbnet_write_cmd(dev, req,
			 USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			 value, regnum, NULL, 0);
}

static inline void
nc_register_write(struct usbnet *dev, u8 regnum, u16 value)
{
	nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
}


#if 0
static void nc_dump_registers(struct usbnet *dev)
{
	u8	reg;
	u16	*vp = kmalloc(sizeof (u16));

	if (!vp)
		return;

	netdev_dbg(dev->net, "registers:\n");
	for (reg = 0; reg < 0x20; reg++) {
		int retval;

		// reading some registers is trouble
		if (reg >= 0x08 && reg <= 0xf)
			continue;
		if (reg >= 0x12 && reg <= 0x1e)
			continue;

		retval = nc_register_read(dev, reg, vp);
		if (retval < 0)
			netdev_dbg(dev->net, "reg [0x%x] ==> error %d\n",
				   reg, retval);
		else
			netdev_dbg(dev->net, "reg [0x%x] = 0x%x\n", reg, *vp);
	}
	kfree(vp);
}
#endif


/*-------------------------------------------------------------------------*/

/*
 * Control register
 */

#define	USBCTL_WRITABLE_MASK	0x1f0f
// bits 15-13 reserved, r/o
#define	USBCTL_ENABLE_LANG	(1 << 12)
#define	USBCTL_ENABLE_MFGR	(1 << 11)
#define	USBCTL_ENABLE_PROD	(1 << 10)
#define	USBCTL_ENABLE_SERIAL	(1 << 9)
#define	USBCTL_ENABLE_DEFAULTS	(1 << 8)
// bits 7-4 reserved, r/o
#define	USBCTL_FLUSH_OTHER	(1 << 3)
#define	USBCTL_FLUSH_THIS	(1 << 2)
#define	USBCTL_DISCONN_OTHER	(1 << 1)
#define	USBCTL_DISCONN_THIS	(1 << 0)

static inline void nc_dump_usbctl(struct usbnet *dev, u16 usbctl)
{
	netif_dbg(dev, link, dev->net,
		  "net1080 %s-%s usbctl 0x%x:%s%s%s%s%s; this%s%s; other%s%s; r/o 0x%x\n",
		  dev->udev->bus->bus_name, dev->udev->devpath,
		  usbctl,
		  (usbctl & USBCTL_ENABLE_LANG) ? " lang" : "",
		  (usbctl & USBCTL_ENABLE_MFGR) ? " mfgr" : "",
		  (usbctl & USBCTL_ENABLE_PROD) ? " prod" : "",
		  (usbctl & USBCTL_ENABLE_SERIAL) ? " serial" : "",
		  (usbctl & USBCTL_ENABLE_DEFAULTS) ? " defaults" : "",

		  (usbctl & USBCTL_FLUSH_THIS) ? " FLUSH" : "",
		  (usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",

		  (usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
		  (usbctl & USBCTL_DISCONN_OTHER) ? " DIS" : "",

		  usbctl & ~USBCTL_WRITABLE_MASK);
}

/*-------------------------------------------------------------------------*/

/*
 * Status register
 */

#define	STATUS_PORT_A		(1 << 15)

#define	STATUS_CONN_OTHER	(1 << 14)
#define	STATUS_SUSPEND_OTHER	(1 << 13)
#define	STATUS_MAILBOX_OTHER	(1 << 12)
#define	STATUS_PACKETS_OTHER(n)	(((n) >> 8) & 0x03)

#define	STATUS_CONN_THIS	(1 << 6)
#define	STATUS_SUSPEND_THIS	(1 << 5)
#define	STATUS_MAILBOX_THIS	(1 << 4)
#define	STATUS_PACKETS_THIS(n)	(((n) >> 0) & 0x03)

#define	STATUS_UNSPEC_MASK	0x0c8c
#define	STATUS_NOISE_MASK 	((u16)~(0x0303|STATUS_UNSPEC_MASK))


static inline void nc_dump_status(struct usbnet *dev, u16 status)
{
	netif_dbg(dev, link, dev->net,
		  "net1080 %s-%s status 0x%x: this (%c) PKT=%d%s%s%s; other PKT=%d%s%s%s; unspec 0x%x\n",
		  dev->udev->bus->bus_name, dev->udev->devpath,
		  status,

		  // XXX the packet counts don't seem right
		  // (1 at reset, not 0); maybe UNSPEC too

		  (status & STATUS_PORT_A) ? 'A' : 'B',
		  STATUS_PACKETS_THIS(status),
		  (status & STATUS_CONN_THIS) ? " CON" : "",
		  (status & STATUS_SUSPEND_THIS) ? " SUS" : "",
		  (status & STATUS_MAILBOX_THIS) ? " MBOX" : "",

		  STATUS_PACKETS_OTHER(status),
		  (status & STATUS_CONN_OTHER) ? " CON" : "",
		  (status & STATUS_SUSPEND_OTHER) ? " SUS" : "",
		  (status & STATUS_MAILBOX_OTHER) ? " MBOX" : "",

		  status & STATUS_UNSPEC_MASK);
}

/*-------------------------------------------------------------------------*/

/*
 * TTL register
 */

#define	TTL_OTHER(ttl)	(0x00ff & (ttl >> 8))
#define MK_TTL(this,other)	((u16)(((other)<<8)|(0x00ff&(this))))

/*-------------------------------------------------------------------------*/

static int net1080_reset(struct usbnet *dev)
{
	u16		usbctl, status, ttl;
	u16		vp;
	int		retval;

	// nc_dump_registers(dev);

	if ((retval = nc_register_read(dev, REG_STATUS, &vp)) < 0) {
		netdev_dbg(dev->net, "can't read %s-%s status: %d\n",
			   dev->udev->bus->bus_name, dev->udev->devpath, retval);
		goto done;
	}
	status = vp;
	nc_dump_status(dev, status);

	if ((retval = nc_register_read(dev, REG_USBCTL, &vp)) < 0) {
		netdev_dbg(dev->net, "can't read USBCTL, %d\n", retval);
		goto done;
	}
	usbctl = vp;
	nc_dump_usbctl(dev, usbctl);

	nc_register_write(dev, REG_USBCTL,
			USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);

	if ((retval = nc_register_read(dev, REG_TTL, &vp)) < 0) {
		netdev_dbg(dev->net, "can't read TTL, %d\n", retval);
		goto done;
	}
	ttl = vp;

	nc_register_write(dev, REG_TTL,
			MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
	netdev_dbg(dev->net, "assigned TTL, %d ms\n", NC_READ_TTL_MS);

	netif_info(dev, link, dev->net, "port %c, peer %sconnected\n",
		   (status & STATUS_PORT_A) ? 'A' : 'B',
		   (status & STATUS_CONN_OTHER) ? "" : "dis");
	retval = 0;

done:
	return retval;
}

static int net1080_check_connect(struct usbnet *dev)
{
	int			retval;
	u16			status;
	u16			vp;

	retval = nc_register_read(dev, REG_STATUS, &vp);
	status = vp;
	if (retval != 0) {
		netdev_dbg(dev->net, "net1080_check_conn read - %d\n", retval);
		return retval;
	}
	if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
		return -ENOLINK;
	return 0;
}

static void nc_ensure_sync(struct usbnet *dev)
{
	if (++dev->frame_errors <= 5)
		return;

	if (usbnet_write_cmd_async(dev, REQUEST_REGISTER,
					USB_DIR_OUT | USB_TYPE_VENDOR |
					USB_RECIP_DEVICE,
					USBCTL_FLUSH_THIS |
					USBCTL_FLUSH_OTHER,
					REG_USBCTL, NULL, 0))
		return;

	netif_dbg(dev, rx_err, dev->net,
		  "flush net1080; too many framing errors\n");
	dev->frame_errors = 0;
}

static int net1080_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
	struct nc_header	*header;
	struct nc_trailer	*trailer;
	u16			hdr_len, packet_len;

	/* This check is no longer done by usbnet */
	if (skb->len < dev->net->hard_header_len)
		return 0;

	if (!(skb->len & 0x01)) {
		netdev_dbg(dev->net, "rx framesize %d range %d..%d mtu %d\n",
			   skb->len, dev->net->hard_header_len, dev->hard_mtu,
			   dev->net->mtu);
		dev->net->stats.rx_frame_errors++;
		nc_ensure_sync(dev);
		return 0;
	}

	header = (struct nc_header *) skb->data;
	hdr_len = le16_to_cpup(&header->hdr_len);
	packet_len = le16_to_cpup(&header->packet_len);
	if (FRAMED_SIZE(packet_len) > NC_MAX_PACKET) {
		dev->net->stats.rx_frame_errors++;
		netdev_dbg(dev->net, "packet too big, %d\n", packet_len);
		nc_ensure_sync(dev);
		return 0;
	} else if (hdr_len < MIN_HEADER) {
		dev->net->stats.rx_frame_errors++;
		netdev_dbg(dev->net, "header too short, %d\n", hdr_len);
		nc_ensure_sync(dev);
		return 0;
	} else if (hdr_len > MIN_HEADER) {
		// out of band data for us?
		netdev_dbg(dev->net, "header OOB, %d bytes\n", hdr_len - MIN_HEADER);
		nc_ensure_sync(dev);
		// switch (vendor/product ids) { ... }
	}
	skb_pull(skb, hdr_len);

	trailer = (struct nc_trailer *)
		(skb->data + skb->len - sizeof *trailer);
	skb_trim(skb, skb->len - sizeof *trailer);

	if ((packet_len & 0x01) == 0) {
		if (skb->data [packet_len] != PAD_BYTE) {
			dev->net->stats.rx_frame_errors++;
			netdev_dbg(dev->net, "bad pad\n");
			return 0;
		}
		skb_trim(skb, skb->len - 1);
	}
	if (skb->len != packet_len) {
		dev->net->stats.rx_frame_errors++;
		netdev_dbg(dev->net, "bad packet len %d (expected %d)\n",
			   skb->len, packet_len);
		nc_ensure_sync(dev);
		return 0;
	}
	if (header->packet_id != get_unaligned(&trailer->packet_id)) {
		dev->net->stats.rx_fifo_errors++;
		netdev_dbg(dev->net, "(2+ dropped) rx packet_id mismatch 0x%x 0x%x\n",
			   le16_to_cpu(header->packet_id),
			   le16_to_cpu(trailer->packet_id));
		return 0;
	}
#if 0
	netdev_dbg(dev->net, "frame <rx h %d p %d id %d\n", header->hdr_len,
		   header->packet_len, header->packet_id);
#endif
	dev->frame_errors = 0;
	return 1;
}

static struct sk_buff *
net1080_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	struct sk_buff		*skb2;
	struct nc_header	*header = NULL;
	struct nc_trailer	*trailer = NULL;
	int			padlen = sizeof (struct nc_trailer);
	int			len = skb->len;

	if (!((len + padlen + sizeof (struct nc_header)) & 0x01))
		padlen++;
	if (!skb_cloned(skb)) {
		int	headroom = skb_headroom(skb);
		int	tailroom = skb_tailroom(skb);

		if (padlen <= tailroom &&
		    sizeof(struct nc_header) <= headroom)
			/* There's enough head and tail room */
			goto encapsulate;

		if ((sizeof (struct nc_header) + padlen) <
				(headroom + tailroom)) {
			/* There's enough total room, so just readjust */
			skb->data = memmove(skb->head
						+ sizeof (struct nc_header),
					    skb->data, skb->len);
			skb_set_tail_pointer(skb, len);
			goto encapsulate;
		}
	}

	/* Create a new skb to use with the correct size */
	skb2 = skb_copy_expand(skb,
				sizeof (struct nc_header),
				padlen,
				flags);
	dev_kfree_skb_any(skb);
	if (!skb2)
		return skb2;
	skb = skb2;

encapsulate:
	/* header first */
	header = skb_push(skb, sizeof *header);
	header->hdr_len = cpu_to_le16(sizeof (*header));
	header->packet_len = cpu_to_le16(len);
	header->packet_id = cpu_to_le16((u16)dev->xid++);

	/* maybe pad; then trailer */
	if (!((skb->len + sizeof *trailer) & 0x01))
		skb_put_u8(skb, PAD_BYTE);
	trailer = skb_put(skb, sizeof *trailer);
	put_unaligned(header->packet_id, &trailer->packet_id);
#if 0
	netdev_dbg(dev->net, "frame >tx h %d p %d id %d\n",
		   header->hdr_len, header->packet_len,
		   header->packet_id);
#endif
	return skb;
}

static int net1080_bind(struct usbnet *dev, struct usb_interface *intf)
{
	unsigned	extra = sizeof (struct nc_header)
				+ 1
				+ sizeof (struct nc_trailer);

	dev->net->hard_header_len += extra;
	dev->rx_urb_size = dev->net->hard_header_len + dev->net->mtu;
	dev->hard_mtu = NC_MAX_PACKET;
	return usbnet_get_endpoints (dev, intf);
}

static const struct driver_info	net1080_info = {
	.description =	"NetChip TurboCONNECT",
	.flags =	FLAG_POINTTOPOINT | FLAG_FRAMING_NC,
	.bind =		net1080_bind,
	.reset =	net1080_reset,
	.check_connect = net1080_check_connect,
	.rx_fixup =	net1080_rx_fixup,
	.tx_fixup =	net1080_tx_fixup,
};

static const struct usb_device_id	products [] = {
{
	USB_DEVICE(0x0525, 0x1080),	// NetChip ref design
	.driver_info =	(unsigned long) &net1080_info,
}, {
	USB_DEVICE(0x06D0, 0x0622),	// Laplink Gold
	.driver_info =	(unsigned long) &net1080_info,
},
	{ },		// END
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver net1080_driver = {
	.name =		"net1080",
	.id_table =	products,
	.probe =	usbnet_probe,
	.disconnect =	usbnet_disconnect,
	.suspend =	usbnet_suspend,
	.resume =	usbnet_resume,
	.disable_hub_initiated_lpm = 1,
};

module_usb_driver(net1080_driver);

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
MODULE_LICENSE("GPL");