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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / net / usb / net1080.c
blob1f04f172042664d92dcf80e625ab7190828d0da3
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
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
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 // no retval ... can become async, usable in_interrupt()
117 static void
118 nc_vendor_write(struct usbnet *dev, u8 req, u8 regnum, u16 value)
119 {
120 usbnet_write_cmd(dev, req,
121 USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
122 value, regnum, NULL, 0);
123 }
124
125 static inline void
126 nc_register_write(struct usbnet *dev, u8 regnum, u16 value)
127 {
128 nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
129 }
130
131
132 #if 0
133 static void nc_dump_registers(struct usbnet *dev)
134 {
135 u8 reg;
136 u16 *vp = kmalloc(sizeof (u16));
137
138 if (!vp)
139 return;
140
141 netdev_dbg(dev->net, "registers:\n");
142 for (reg = 0; reg < 0x20; reg++) {
143 int retval;
144
145 // reading some registers is trouble
146 if (reg >= 0x08 && reg <= 0xf)
147 continue;
148 if (reg >= 0x12 && reg <= 0x1e)
149 continue;
150
151 retval = nc_register_read(dev, reg, vp);
152 if (retval < 0)
153 netdev_dbg(dev->net, "reg [0x%x] ==> error %d\n",
154 reg, retval);
155 else
156 netdev_dbg(dev->net, "reg [0x%x] = 0x%x\n", reg, *vp);
157 }
158 kfree(vp);
159 }
160 #endif
161
162
163 /*-------------------------------------------------------------------------*/
164
165 /*
166 * Control register
167 */
168
169 #define USBCTL_WRITABLE_MASK 0x1f0f
170 // bits 15-13 reserved, r/o
171 #define USBCTL_ENABLE_LANG (1 << 12)
172 #define USBCTL_ENABLE_MFGR (1 << 11)
173 #define USBCTL_ENABLE_PROD (1 << 10)
174 #define USBCTL_ENABLE_SERIAL (1 << 9)
175 #define USBCTL_ENABLE_DEFAULTS (1 << 8)
176 // bits 7-4 reserved, r/o
177 #define USBCTL_FLUSH_OTHER (1 << 3)
178 #define USBCTL_FLUSH_THIS (1 << 2)
179 #define USBCTL_DISCONN_OTHER (1 << 1)
180 #define USBCTL_DISCONN_THIS (1 << 0)
181
182 static inline void nc_dump_usbctl(struct usbnet *dev, u16 usbctl)
183 {
184 netif_dbg(dev, link, dev->net,
185 "net1080 %s-%s usbctl 0x%x:%s%s%s%s%s; this%s%s; other%s%s; r/o 0x%x\n",
186 dev->udev->bus->bus_name, dev->udev->devpath,
187 usbctl,
188 (usbctl & USBCTL_ENABLE_LANG) ? " lang" : "",
189 (usbctl & USBCTL_ENABLE_MFGR) ? " mfgr" : "",
190 (usbctl & USBCTL_ENABLE_PROD) ? " prod" : "",
191 (usbctl & USBCTL_ENABLE_SERIAL) ? " serial" : "",
192 (usbctl & USBCTL_ENABLE_DEFAULTS) ? " defaults" : "",
193
194 (usbctl & USBCTL_FLUSH_THIS) ? " FLUSH" : "",
195 (usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",
196
197 (usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
198 (usbctl & USBCTL_DISCONN_OTHER) ? " DIS" : "",
199
200 usbctl & ~USBCTL_WRITABLE_MASK);
201 }
202
203 /*-------------------------------------------------------------------------*/
204
205 /*
206 * Status register
207 */
208
209 #define STATUS_PORT_A (1 << 15)
210
211 #define STATUS_CONN_OTHER (1 << 14)
212 #define STATUS_SUSPEND_OTHER (1 << 13)
213 #define STATUS_MAILBOX_OTHER (1 << 12)
214 #define STATUS_PACKETS_OTHER(n) (((n) >> 8) & 0x03)
215
216 #define STATUS_CONN_THIS (1 << 6)
217 #define STATUS_SUSPEND_THIS (1 << 5)
218 #define STATUS_MAILBOX_THIS (1 << 4)
219 #define STATUS_PACKETS_THIS(n) (((n) >> 0) & 0x03)
220
221 #define STATUS_UNSPEC_MASK 0x0c8c
222 #define STATUS_NOISE_MASK ((u16)~(0x0303|STATUS_UNSPEC_MASK))
223
224
225 static inline void nc_dump_status(struct usbnet *dev, u16 status)
226 {
227 netif_dbg(dev, link, dev->net,
228 "net1080 %s-%s status 0x%x: this (%c) PKT=%d%s%s%s; other PKT=%d%s%s%s; unspec 0x%x\n",
229 dev->udev->bus->bus_name, dev->udev->devpath,
230 status,
231
232 // XXX the packet counts don't seem right
233 // (1 at reset, not 0); maybe UNSPEC too
234
235 (status & STATUS_PORT_A) ? 'A' : 'B',
236 STATUS_PACKETS_THIS(status),
237 (status & STATUS_CONN_THIS) ? " CON" : "",
238 (status & STATUS_SUSPEND_THIS) ? " SUS" : "",
239 (status & STATUS_MAILBOX_THIS) ? " MBOX" : "",
240
241 STATUS_PACKETS_OTHER(status),
242 (status & STATUS_CONN_OTHER) ? " CON" : "",
243 (status & STATUS_SUSPEND_OTHER) ? " SUS" : "",
244 (status & STATUS_MAILBOX_OTHER) ? " MBOX" : "",
245
246 status & STATUS_UNSPEC_MASK);
247 }
248
249 /*-------------------------------------------------------------------------*/
250
251 /*
252 * TTL register
253 */
254
255 #define TTL_OTHER(ttl) (0x00ff & (ttl >> 8))
256 #define MK_TTL(this,other) ((u16)(((other)<<8)|(0x00ff&(this))))
257
258 /*-------------------------------------------------------------------------*/
259
260 static int net1080_reset(struct usbnet *dev)
261 {
262 u16 usbctl, status, ttl;
263 u16 vp;
264 int retval;
265
266 // nc_dump_registers(dev);
267
268 if ((retval = nc_register_read(dev, REG_STATUS, &vp)) < 0) {
269 netdev_dbg(dev->net, "can't read %s-%s status: %d\n",
270 dev->udev->bus->bus_name, dev->udev->devpath, retval);
271 goto done;
272 }
273 status = vp;
274 nc_dump_status(dev, status);
275
276 if ((retval = nc_register_read(dev, REG_USBCTL, &vp)) < 0) {
277 netdev_dbg(dev->net, "can't read USBCTL, %d\n", retval);
278 goto done;
279 }
280 usbctl = vp;
281 nc_dump_usbctl(dev, usbctl);
282
283 nc_register_write(dev, REG_USBCTL,
284 USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
285
286 if ((retval = nc_register_read(dev, REG_TTL, &vp)) < 0) {
287 netdev_dbg(dev->net, "can't read TTL, %d\n", retval);
288 goto done;
289 }
290 ttl = vp;
291
292 nc_register_write(dev, REG_TTL,
293 MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
294 netdev_dbg(dev->net, "assigned TTL, %d ms\n", NC_READ_TTL_MS);
295
296 netif_info(dev, link, dev->net, "port %c, peer %sconnected\n",
297 (status & STATUS_PORT_A) ? 'A' : 'B',
298 (status & STATUS_CONN_OTHER) ? "" : "dis");
299 retval = 0;
300
301 done:
302 return retval;
303 }
304
305 static int net1080_check_connect(struct usbnet *dev)
306 {
307 int retval;
308 u16 status;
309 u16 vp;
310
311 retval = nc_register_read(dev, REG_STATUS, &vp);
312 status = vp;
313 if (retval != 0) {
314 netdev_dbg(dev->net, "net1080_check_conn read - %d\n", retval);
315 return retval;
316 }
317 if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
318 return -ENOLINK;
319 return 0;
320 }
321
322 static void nc_ensure_sync(struct usbnet *dev)
323 {
324 if (++dev->frame_errors <= 5)
325 return;
326
327 if (usbnet_write_cmd_async(dev, REQUEST_REGISTER,
328 USB_DIR_OUT | USB_TYPE_VENDOR |
329 USB_RECIP_DEVICE,
330 USBCTL_FLUSH_THIS |
331 USBCTL_FLUSH_OTHER,
332 REG_USBCTL, NULL, 0))
333 return;
334
335 netif_dbg(dev, rx_err, dev->net,
336 "flush net1080; too many framing errors\n");
337 dev->frame_errors = 0;
338 }
339
340 static int net1080_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
341 {
342 struct nc_header *header;
343 struct nc_trailer *trailer;
344 u16 hdr_len, packet_len;
345
346 /* This check is no longer done by usbnet */
347 if (skb->len < dev->net->hard_header_len)
348 return 0;
349
350 if (!(skb->len & 0x01)) {
351 netdev_dbg(dev->net, "rx framesize %d range %d..%d mtu %d\n",
352 skb->len, dev->net->hard_header_len, dev->hard_mtu,
353 dev->net->mtu);
354 dev->net->stats.rx_frame_errors++;
355 nc_ensure_sync(dev);
356 return 0;
357 }
358
359 header = (struct nc_header *) skb->data;
360 hdr_len = le16_to_cpup(&header->hdr_len);
361 packet_len = le16_to_cpup(&header->packet_len);
362 if (FRAMED_SIZE(packet_len) > NC_MAX_PACKET) {
363 dev->net->stats.rx_frame_errors++;
364 netdev_dbg(dev->net, "packet too big, %d\n", packet_len);
365 nc_ensure_sync(dev);
366 return 0;
367 } else if (hdr_len < MIN_HEADER) {
368 dev->net->stats.rx_frame_errors++;
369 netdev_dbg(dev->net, "header too short, %d\n", hdr_len);
370 nc_ensure_sync(dev);
371 return 0;
372 } else if (hdr_len > MIN_HEADER) {
373 // out of band data for us?
374 netdev_dbg(dev->net, "header OOB, %d bytes\n", hdr_len - MIN_HEADER);
375 nc_ensure_sync(dev);
376 // switch (vendor/product ids) { ... }
377 }
378 skb_pull(skb, hdr_len);
379
380 trailer = (struct nc_trailer *)
381 (skb->data + skb->len - sizeof *trailer);
382 skb_trim(skb, skb->len - sizeof *trailer);
383
384 if ((packet_len & 0x01) == 0) {
385 if (skb->data [packet_len] != PAD_BYTE) {
386 dev->net->stats.rx_frame_errors++;
387 netdev_dbg(dev->net, "bad pad\n");
388 return 0;
389 }
390 skb_trim(skb, skb->len - 1);
391 }
392 if (skb->len != packet_len) {
393 dev->net->stats.rx_frame_errors++;
394 netdev_dbg(dev->net, "bad packet len %d (expected %d)\n",
395 skb->len, packet_len);
396 nc_ensure_sync(dev);
397 return 0;
398 }
399 if (header->packet_id != get_unaligned(&trailer->packet_id)) {
400 dev->net->stats.rx_fifo_errors++;
401 netdev_dbg(dev->net, "(2+ dropped) rx packet_id mismatch 0x%x 0x%x\n",
402 le16_to_cpu(header->packet_id),
403 le16_to_cpu(trailer->packet_id));
404 return 0;
405 }
406 #if 0
407 netdev_dbg(dev->net, "frame <rx h %d p %d id %d\n", header->hdr_len,
408 header->packet_len, header->packet_id);
409 #endif
410 dev->frame_errors = 0;
411 return 1;
412 }
413
414 static struct sk_buff *
415 net1080_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
416 {
417 struct sk_buff *skb2;
418 struct nc_header *header = NULL;
419 struct nc_trailer *trailer = NULL;
420 int padlen = sizeof (struct nc_trailer);
421 int len = skb->len;
422
423 if (!((len + padlen + sizeof (struct nc_header)) & 0x01))
424 padlen++;
425 if (!skb_cloned(skb)) {
426 int headroom = skb_headroom(skb);
427 int tailroom = skb_tailroom(skb);
428
429 if (padlen <= tailroom &&
430 sizeof(struct nc_header) <= headroom)
431 /* There's enough head and tail room */
432 goto encapsulate;
433
434 if ((sizeof (struct nc_header) + padlen) <
435 (headroom + tailroom)) {
436 /* There's enough total room, so just readjust */
437 skb->data = memmove(skb->head
438 + sizeof (struct nc_header),
439 skb->data, skb->len);
440 skb_set_tail_pointer(skb, len);
441 goto encapsulate;
442 }
443 }
444
445 /* Create a new skb to use with the correct size */
446 skb2 = skb_copy_expand(skb,
447 sizeof (struct nc_header),
448 padlen,
449 flags);
450 dev_kfree_skb_any(skb);
451 if (!skb2)
452 return skb2;
453 skb = skb2;
454
455 encapsulate:
456 /* header first */
457 header = skb_push(skb, sizeof *header);
458 header->hdr_len = cpu_to_le16(sizeof (*header));
459 header->packet_len = cpu_to_le16(len);
460 header->packet_id = cpu_to_le16((u16)dev->xid++);
461
462 /* maybe pad; then trailer */
463 if (!((skb->len + sizeof *trailer) & 0x01))
464 skb_put_u8(skb, PAD_BYTE);
465 trailer = skb_put(skb, sizeof *trailer);
466 put_unaligned(header->packet_id, &trailer->packet_id);
467 #if 0
468 netdev_dbg(dev->net, "frame >tx h %d p %d id %d\n",
469 header->hdr_len, header->packet_len,
470 header->packet_id);
471 #endif
472 return skb;
473 }
474
475 static int net1080_bind(struct usbnet *dev, struct usb_interface *intf)
476 {
477 unsigned extra = sizeof (struct nc_header)
478 + 1
479 + sizeof (struct nc_trailer);
480
481 dev->net->hard_header_len += extra;
482 dev->rx_urb_size = dev->net->hard_header_len + dev->net->mtu;
483 dev->hard_mtu = NC_MAX_PACKET;
484 return usbnet_get_endpoints (dev, intf);
485 }
486
487 static const struct driver_info net1080_info = {
488 .description = "NetChip TurboCONNECT",
489 .flags = FLAG_POINTTOPOINT | FLAG_FRAMING_NC,
490 .bind = net1080_bind,
491 .reset = net1080_reset,
492 .check_connect = net1080_check_connect,
493 .rx_fixup = net1080_rx_fixup,
494 .tx_fixup = net1080_tx_fixup,
495 };
496
497 static const struct usb_device_id products [] = {
498 {
499 USB_DEVICE(0x0525, 0x1080), // NetChip ref design
500 .driver_info = (unsigned long) &net1080_info,
501 }, {
502 USB_DEVICE(0x06D0, 0x0622), // Laplink Gold
503 .driver_info = (unsigned long) &net1080_info,
504 },
505 { }, // END
506 };
507 MODULE_DEVICE_TABLE(usb, products);
508
509 static struct usb_driver net1080_driver = {
510 .name = "net1080",
511 .id_table = products,
512 .probe = usbnet_probe,
513 .disconnect = usbnet_disconnect,
514 .suspend = usbnet_suspend,
515 .resume = usbnet_resume,
516 .disable_hub_initiated_lpm = 1,
517 };
518
519 module_usb_driver(net1080_driver);
520
521 MODULE_AUTHOR("David Brownell");
522 MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
523 MODULE_LICENSE("GPL");
Linux with added FPC-III support