1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Net1080 based USB host-to-host cables
4 * Copyright (C) 2000-2005 by David Brownell
5 */
6
7 // #define DEBUG // error path messages, extra info
8 // #define VERBOSE // more; success messages
9
10 #include <linux/module.h>
11 #include <linux/netdevice.h>
12 #include <linux/etherdevice.h>
13 #include <linux/ethtool.h>
14 #include <linux/workqueue.h>
15 #include <linux/mii.h>
16 #include <linux/usb.h>
17 #include <linux/usb/usbnet.h>
18 #include <linux/slab.h>
19
20 #include <asm/unaligned.h>
21
22
23 /*
24 * Netchip 1080 driver ... http://www.netchip.com
25 * (Sept 2004: End-of-life announcement has been sent.)
26 * Used in (some) LapLink cables
27 */
28
29 #define frame_errors data[1]
30
31 /*
32 * NetChip framing of ethernet packets, supporting additional error
33 * checks for links that may drop bulk packets from inside messages.
34 * Odd USB length == always short read for last usb packet.
35 * - nc_header
36 * - Ethernet header (14 bytes)
37 * - payload
38 * - (optional padding byte, if needed so length becomes odd)
39 * - nc_trailer
40 *
41 * This framing is to be avoided for non-NetChip devices.
42 */
43
44 struct nc_header { // packed:
45 __le16 hdr_len; // sizeof nc_header (LE, all)
46 __le16 packet_len; // payload size (including ethhdr)
47 __le16 packet_id; // detects dropped packets
48 #define MIN_HEADER 6
49
50 // all else is optional, and must start with:
51 // __le16 vendorId; // from usb-if
52 // __le16 productId;
53 } __packed;
54
55 #define PAD_BYTE ((unsigned char)0xAC)
56
57 struct nc_trailer {
58 __le16 packet_id;
59 } __packed;
60
61 // packets may use FLAG_FRAMING_NC and optional pad
62 #define FRAMED_SIZE(mtu) (sizeof (struct nc_header) \
63 + sizeof (struct ethhdr) \
64 + (mtu) \
65 + 1 \
66 + sizeof (struct nc_trailer))
67
68 #define MIN_FRAMED FRAMED_SIZE(0)
69
70 /* packets _could_ be up to 64KB... */
71 #define NC_MAX_PACKET 32767
72
73
74 /*
75 * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
76 * before the hardware drops it. If that's done, the driver will need to
77 * frame network packets to guard against the dropped USB packets. The win32
78 * driver sets this for both sides of the link.
79 */
80 #define NC_READ_TTL_MS ((u8)255) // ms
81
82 /*
83 * We ignore most registers and EEPROM contents.
84 */
85 #define REG_USBCTL ((u8)0x04)
86 #define REG_TTL ((u8)0x10)
87 #define REG_STATUS ((u8)0x11)
88
89 /*
90 * Vendor specific requests to read/write data
91 */
92 #define REQUEST_REGISTER ((u8)0x10)
93 #define REQUEST_EEPROM ((u8)0x11)
94
95 static int
nc_vendor_read(struct usbnet * dev,u8 req,u8 regnum,u16 * retval_ptr)96 nc_vendor_read(struct usbnet *dev, u8 req, u8 regnum, u16 *retval_ptr)
97 {
98 int status = usbnet_read_cmd(dev, req,
99 USB_DIR_IN | USB_TYPE_VENDOR |
100 USB_RECIP_DEVICE,
101 0, regnum, retval_ptr,
102 sizeof *retval_ptr);
103 if (status > 0)
104 status = 0;
105 if (!status)
106 le16_to_cpus(retval_ptr);
107 return status;
108 }
109
110 static inline int
nc_register_read(struct usbnet * dev,u8 regnum,u16 * retval_ptr)111 nc_register_read(struct usbnet *dev, u8 regnum, u16 *retval_ptr)
112 {
113 return nc_vendor_read(dev, REQUEST_REGISTER, regnum, retval_ptr);
114 }
115
116 static void
nc_vendor_write(struct usbnet * dev,u8 req,u8 regnum,u16 value)117 nc_vendor_write(struct usbnet *dev, u8 req, u8 regnum, u16 value)
118 {
119 usbnet_write_cmd(dev, req,
120 USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
121 value, regnum, NULL, 0);
122 }
123
124 static inline void
nc_register_write(struct usbnet * dev,u8 regnum,u16 value)125 nc_register_write(struct usbnet *dev, u8 regnum, u16 value)
126 {
127 nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
128 }
129
130
131 #if 0
132 static void nc_dump_registers(struct usbnet *dev)
133 {
134 u8 reg;
135 u16 *vp = kmalloc(sizeof (u16));
136
137 if (!vp)
138 return;
139
140 netdev_dbg(dev->net, "registers:\n");
141 for (reg = 0; reg < 0x20; reg++) {
142 int retval;
143
144 // reading some registers is trouble
145 if (reg >= 0x08 && reg <= 0xf)
146 continue;
147 if (reg >= 0x12 && reg <= 0x1e)
148 continue;
149
150 retval = nc_register_read(dev, reg, vp);
151 if (retval < 0)
152 netdev_dbg(dev->net, "reg [0x%x] ==> error %d\n",
153 reg, retval);
154 else
155 netdev_dbg(dev->net, "reg [0x%x] = 0x%x\n", reg, *vp);
156 }
157 kfree(vp);
158 }
159 #endif
160
161
162 /*-------------------------------------------------------------------------*/
163
164 /*
165 * Control register
166 */
167
168 #define USBCTL_WRITABLE_MASK 0x1f0f
169 // bits 15-13 reserved, r/o
170 #define USBCTL_ENABLE_LANG (1 << 12)
171 #define USBCTL_ENABLE_MFGR (1 << 11)
172 #define USBCTL_ENABLE_PROD (1 << 10)
173 #define USBCTL_ENABLE_SERIAL (1 << 9)
174 #define USBCTL_ENABLE_DEFAULTS (1 << 8)
175 // bits 7-4 reserved, r/o
176 #define USBCTL_FLUSH_OTHER (1 << 3)
177 #define USBCTL_FLUSH_THIS (1 << 2)
178 #define USBCTL_DISCONN_OTHER (1 << 1)
179 #define USBCTL_DISCONN_THIS (1 << 0)
180
nc_dump_usbctl(struct usbnet * dev,u16 usbctl)181 static inline void nc_dump_usbctl(struct usbnet *dev, u16 usbctl)
182 {
183 netif_dbg(dev, link, dev->net,
184 "net1080 %s-%s usbctl 0x%x:%s%s%s%s%s; this%s%s; other%s%s; r/o 0x%x\n",
185 dev->udev->bus->bus_name, dev->udev->devpath,
186 usbctl,
187 (usbctl & USBCTL_ENABLE_LANG) ? " lang" : "",
188 (usbctl & USBCTL_ENABLE_MFGR) ? " mfgr" : "",
189 (usbctl & USBCTL_ENABLE_PROD) ? " prod" : "",
190 (usbctl & USBCTL_ENABLE_SERIAL) ? " serial" : "",
191 (usbctl & USBCTL_ENABLE_DEFAULTS) ? " defaults" : "",
192
193 (usbctl & USBCTL_FLUSH_THIS) ? " FLUSH" : "",
194 (usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",
195
196 (usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
197 (usbctl & USBCTL_DISCONN_OTHER) ? " DIS" : "",
198
199 usbctl & ~USBCTL_WRITABLE_MASK);
200 }
201
202 /*-------------------------------------------------------------------------*/
203
204 /*
205 * Status register
206 */
207
208 #define STATUS_PORT_A (1 << 15)
209
210 #define STATUS_CONN_OTHER (1 << 14)
211 #define STATUS_SUSPEND_OTHER (1 << 13)
212 #define STATUS_MAILBOX_OTHER (1 << 12)
213 #define STATUS_PACKETS_OTHER(n) (((n) >> 8) & 0x03)
214
215 #define STATUS_CONN_THIS (1 << 6)
216 #define STATUS_SUSPEND_THIS (1 << 5)
217 #define STATUS_MAILBOX_THIS (1 << 4)
218 #define STATUS_PACKETS_THIS(n) (((n) >> 0) & 0x03)
219
220 #define STATUS_UNSPEC_MASK 0x0c8c
221 #define STATUS_NOISE_MASK ((u16)~(0x0303|STATUS_UNSPEC_MASK))
222
223
nc_dump_status(struct usbnet * dev,u16 status)224 static inline void nc_dump_status(struct usbnet *dev, u16 status)
225 {
226 netif_dbg(dev, link, dev->net,
227 "net1080 %s-%s status 0x%x: this (%c) PKT=%d%s%s%s; other PKT=%d%s%s%s; unspec 0x%x\n",
228 dev->udev->bus->bus_name, dev->udev->devpath,
229 status,
230
231 // XXX the packet counts don't seem right
232 // (1 at reset, not 0); maybe UNSPEC too
233
234 (status & STATUS_PORT_A) ? 'A' : 'B',
235 STATUS_PACKETS_THIS(status),
236 (status & STATUS_CONN_THIS) ? " CON" : "",
237 (status & STATUS_SUSPEND_THIS) ? " SUS" : "",
238 (status & STATUS_MAILBOX_THIS) ? " MBOX" : "",
239
240 STATUS_PACKETS_OTHER(status),
241 (status & STATUS_CONN_OTHER) ? " CON" : "",
242 (status & STATUS_SUSPEND_OTHER) ? " SUS" : "",
243 (status & STATUS_MAILBOX_OTHER) ? " MBOX" : "",
244
245 status & STATUS_UNSPEC_MASK);
246 }
247
248 /*-------------------------------------------------------------------------*/
249
250 /*
251 * TTL register
252 */
253
254 #define TTL_OTHER(ttl) (0x00ff & (ttl >> 8))
255 #define MK_TTL(this,other) ((u16)(((other)<<8)|(0x00ff&(this))))
256
257 /*-------------------------------------------------------------------------*/
258
net1080_reset(struct usbnet * dev)259 static int net1080_reset(struct usbnet *dev)
260 {
261 u16 usbctl, status, ttl;
262 u16 vp;
263 int retval;
264
265 // nc_dump_registers(dev);
266
267 if ((retval = nc_register_read(dev, REG_STATUS, &vp)) < 0) {
268 netdev_dbg(dev->net, "can't read %s-%s status: %d\n",
269 dev->udev->bus->bus_name, dev->udev->devpath, retval);
270 goto done;
271 }
272 status = vp;
273 nc_dump_status(dev, status);
274
275 if ((retval = nc_register_read(dev, REG_USBCTL, &vp)) < 0) {
276 netdev_dbg(dev->net, "can't read USBCTL, %d\n", retval);
277 goto done;
278 }
279 usbctl = vp;
280 nc_dump_usbctl(dev, usbctl);
281
282 nc_register_write(dev, REG_USBCTL,
283 USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
284
285 if ((retval = nc_register_read(dev, REG_TTL, &vp)) < 0) {
286 netdev_dbg(dev->net, "can't read TTL, %d\n", retval);
287 goto done;
288 }
289 ttl = vp;
290
291 nc_register_write(dev, REG_TTL,
292 MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
293 netdev_dbg(dev->net, "assigned TTL, %d ms\n", NC_READ_TTL_MS);
294
295 netif_info(dev, link, dev->net, "port %c, peer %sconnected\n",
296 (status & STATUS_PORT_A) ? 'A' : 'B',
297 (status & STATUS_CONN_OTHER) ? "" : "dis");
298 retval = 0;
299
300 done:
301 return retval;
302 }
303
net1080_check_connect(struct usbnet * dev)304 static int net1080_check_connect(struct usbnet *dev)
305 {
306 int retval;
307 u16 status;
308 u16 vp;
309
310 retval = nc_register_read(dev, REG_STATUS, &vp);
311 status = vp;
312 if (retval != 0) {
313 netdev_dbg(dev->net, "net1080_check_conn read - %d\n", retval);
314 return retval;
315 }
316 if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
317 return -ENOLINK;
318 return 0;
319 }
320
nc_ensure_sync(struct usbnet * dev)321 static void nc_ensure_sync(struct usbnet *dev)
322 {
323 if (++dev->frame_errors <= 5)
324 return;
325
326 if (usbnet_write_cmd_async(dev, REQUEST_REGISTER,
327 USB_DIR_OUT | USB_TYPE_VENDOR |
328 USB_RECIP_DEVICE,
329 USBCTL_FLUSH_THIS |
330 USBCTL_FLUSH_OTHER,
331 REG_USBCTL, NULL, 0))
332 return;
333
334 netif_dbg(dev, rx_err, dev->net,
335 "flush net1080; too many framing errors\n");
336 dev->frame_errors = 0;
337 }
338
net1080_rx_fixup(struct usbnet * dev,struct sk_buff * skb)339 static int net1080_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
340 {
341 struct nc_header *header;
342 struct nc_trailer *trailer;
343 u16 hdr_len, packet_len;
344
345 /* This check is no longer done by usbnet */
346 if (skb->len < dev->net->hard_header_len)
347 return 0;
348
349 if (!(skb->len & 0x01)) {
350 netdev_dbg(dev->net, "rx framesize %d range %d..%d mtu %d\n",
351 skb->len, dev->net->hard_header_len, dev->hard_mtu,
352 dev->net->mtu);
353 dev->net->stats.rx_frame_errors++;
354 nc_ensure_sync(dev);
355 return 0;
356 }
357
358 header = (struct nc_header *) skb->data;
359 hdr_len = le16_to_cpup(&header->hdr_len);
360 packet_len = le16_to_cpup(&header->packet_len);
361 if (FRAMED_SIZE(packet_len) > NC_MAX_PACKET) {
362 dev->net->stats.rx_frame_errors++;
363 netdev_dbg(dev->net, "packet too big, %d\n", packet_len);
364 nc_ensure_sync(dev);
365 return 0;
366 } else if (hdr_len < MIN_HEADER) {
367 dev->net->stats.rx_frame_errors++;
368 netdev_dbg(dev->net, "header too short, %d\n", hdr_len);
369 nc_ensure_sync(dev);
370 return 0;
371 } else if (hdr_len > MIN_HEADER) {
372 // out of band data for us?
373 netdev_dbg(dev->net, "header OOB, %d bytes\n", hdr_len - MIN_HEADER);
374 nc_ensure_sync(dev);
375 // switch (vendor/product ids) { ... }
376 }
377 skb_pull(skb, hdr_len);
378
379 trailer = (struct nc_trailer *)
380 (skb->data + skb->len - sizeof *trailer);
381 skb_trim(skb, skb->len - sizeof *trailer);
382
383 if ((packet_len & 0x01) == 0) {
384 if (skb->data [packet_len] != PAD_BYTE) {
385 dev->net->stats.rx_frame_errors++;
386 netdev_dbg(dev->net, "bad pad\n");
387 return 0;
388 }
389 skb_trim(skb, skb->len - 1);
390 }
391 if (skb->len != packet_len) {
392 dev->net->stats.rx_frame_errors++;
393 netdev_dbg(dev->net, "bad packet len %d (expected %d)\n",
394 skb->len, packet_len);
395 nc_ensure_sync(dev);
396 return 0;
397 }
398 if (header->packet_id != get_unaligned(&trailer->packet_id)) {
399 dev->net->stats.rx_fifo_errors++;
400 netdev_dbg(dev->net, "(2+ dropped) rx packet_id mismatch 0x%x 0x%x\n",
401 le16_to_cpu(header->packet_id),
402 le16_to_cpu(trailer->packet_id));
403 return 0;
404 }
405 #if 0
406 netdev_dbg(dev->net, "frame <rx h %d p %d id %d\n", header->hdr_len,
407 header->packet_len, header->packet_id);
408 #endif
409 dev->frame_errors = 0;
410 return 1;
411 }
412
413 static struct sk_buff *
net1080_tx_fixup(struct usbnet * dev,struct sk_buff * skb,gfp_t flags)414 net1080_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
415 {
416 struct sk_buff *skb2;
417 struct nc_header *header = NULL;
418 struct nc_trailer *trailer = NULL;
419 int padlen = sizeof (struct nc_trailer);
420 int len = skb->len;
421
422 if (!((len + padlen + sizeof (struct nc_header)) & 0x01))
423 padlen++;
424 if (!skb_cloned(skb)) {
425 int headroom = skb_headroom(skb);
426 int tailroom = skb_tailroom(skb);
427
428 if (padlen <= tailroom &&
429 sizeof(struct nc_header) <= headroom)
430 /* There's enough head and tail room */
431 goto encapsulate;
432
433 if ((sizeof (struct nc_header) + padlen) <
434 (headroom + tailroom)) {
435 /* There's enough total room, so just readjust */
436 skb->data = memmove(skb->head
437 + sizeof (struct nc_header),
438 skb->data, skb->len);
439 skb_set_tail_pointer(skb, len);
440 goto encapsulate;
441 }
442 }
443
444 /* Create a new skb to use with the correct size */
445 skb2 = skb_copy_expand(skb,
446 sizeof (struct nc_header),
447 padlen,
448 flags);
449 dev_kfree_skb_any(skb);
450 if (!skb2)
451 return skb2;
452 skb = skb2;
453
454 encapsulate:
455 /* header first */
456 header = skb_push(skb, sizeof *header);
457 header->hdr_len = cpu_to_le16(sizeof (*header));
458 header->packet_len = cpu_to_le16(len);
459 header->packet_id = cpu_to_le16((u16)dev->xid++);
460
461 /* maybe pad; then trailer */
462 if (!((skb->len + sizeof *trailer) & 0x01))
463 skb_put_u8(skb, PAD_BYTE);
464 trailer = skb_put(skb, sizeof *trailer);
465 put_unaligned(header->packet_id, &trailer->packet_id);
466 #if 0
467 netdev_dbg(dev->net, "frame >tx h %d p %d id %d\n",
468 header->hdr_len, header->packet_len,
469 header->packet_id);
470 #endif
471 return skb;
472 }
473
net1080_bind(struct usbnet * dev,struct usb_interface * intf)474 static int net1080_bind(struct usbnet *dev, struct usb_interface *intf)
475 {
476 unsigned extra = sizeof (struct nc_header)
477 + 1
478 + sizeof (struct nc_trailer);
479
480 dev->net->hard_header_len += extra;
481 dev->rx_urb_size = dev->net->hard_header_len + dev->net->mtu;
482 dev->hard_mtu = NC_MAX_PACKET;
483 return usbnet_get_endpoints (dev, intf);
484 }
485
486 static const struct driver_info net1080_info = {
487 .description = "NetChip TurboCONNECT",
488 .flags = FLAG_POINTTOPOINT | FLAG_FRAMING_NC,
489 .bind = net1080_bind,
490 .reset = net1080_reset,
491 .check_connect = net1080_check_connect,
492 .rx_fixup = net1080_rx_fixup,
493 .tx_fixup = net1080_tx_fixup,
494 };
495
496 static const struct usb_device_id products [] = {
497 {
498 USB_DEVICE(0x0525, 0x1080), // NetChip ref design
499 .driver_info = (unsigned long) &net1080_info,
500 }, {
501 USB_DEVICE(0x06D0, 0x0622), // Laplink Gold
502 .driver_info = (unsigned long) &net1080_info,
503 },
504 { }, // END
505 };
506 MODULE_DEVICE_TABLE(usb, products);
507
508 static struct usb_driver net1080_driver = {
509 .name = "net1080",
510 .id_table = products,
511 .probe = usbnet_probe,
512 .disconnect = usbnet_disconnect,
513 .suspend = usbnet_suspend,
514 .resume = usbnet_resume,
515 .disable_hub_initiated_lpm = 1,
516 };
517
518 module_usb_driver(net1080_driver);
519
520 MODULE_AUTHOR("David Brownell");
521 MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
522 MODULE_LICENSE("GPL");
523