drivers/net/usb/net1080.c

   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 static void
 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
 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
 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
 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
 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
 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
 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
 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 *
 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
 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");