linux/drivers/net/usb/net1080.c
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   1/*
   2 * Net1080 based USB host-to-host cables
   3 * Copyright (C) 2000-2005 by David Brownell
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19// #define      DEBUG                   // error path messages, extra info
  20// #define      VERBOSE                 // more; success messages
  21
  22#include <linux/module.h>
  23#include <linux/netdevice.h>
  24#include <linux/etherdevice.h>
  25#include <linux/ethtool.h>
  26#include <linux/workqueue.h>
  27#include <linux/mii.h>
  28#include <linux/usb.h>
  29#include <linux/usb/usbnet.h>
  30#include <linux/slab.h>
  31
  32#include <asm/unaligned.h>
  33
  34
  35/*
  36 * Netchip 1080 driver ... http://www.netchip.com
  37 * (Sept 2004:  End-of-life announcement has been sent.)
  38 * Used in (some) LapLink cables
  39 */
  40
  41#define frame_errors    data[1]
  42
  43/*
  44 * NetChip framing of ethernet packets, supporting additional error
  45 * checks for links that may drop bulk packets from inside messages.
  46 * Odd USB length == always short read for last usb packet.
  47 *      - nc_header
  48 *      - Ethernet header (14 bytes)
  49 *      - payload
  50 *      - (optional padding byte, if needed so length becomes odd)
  51 *      - nc_trailer
  52 *
  53 * This framing is to be avoided for non-NetChip devices.
  54 */
  55
  56struct nc_header {              // packed:
  57        __le16  hdr_len;                // sizeof nc_header (LE, all)
  58        __le16  packet_len;             // payload size (including ethhdr)
  59        __le16  packet_id;              // detects dropped packets
  60#define MIN_HEADER      6
  61
  62        // all else is optional, and must start with:
  63        // __le16       vendorId;       // from usb-if
  64        // __le16       productId;
  65} __packed;
  66
  67#define PAD_BYTE        ((unsigned char)0xAC)
  68
  69struct nc_trailer {
  70        __le16  packet_id;
  71} __packed;
  72
  73// packets may use FLAG_FRAMING_NC and optional pad
  74#define FRAMED_SIZE(mtu) (sizeof (struct nc_header) \
  75                                + sizeof (struct ethhdr) \
  76                                + (mtu) \
  77                                + 1 \
  78                                + sizeof (struct nc_trailer))
  79
  80#define MIN_FRAMED      FRAMED_SIZE(0)
  81
  82/* packets _could_ be up to 64KB... */
  83#define NC_MAX_PACKET   32767
  84
  85
  86/*
  87 * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
  88 * before the hardware drops it.  If that's done, the driver will need to
  89 * frame network packets to guard against the dropped USB packets.  The win32
  90 * driver sets this for both sides of the link.
  91 */
  92#define NC_READ_TTL_MS  ((u8)255)       // ms
  93
  94/*
  95 * We ignore most registers and EEPROM contents.
  96 */
  97#define REG_USBCTL      ((u8)0x04)
  98#define REG_TTL         ((u8)0x10)
  99#define REG_STATUS      ((u8)0x11)
 100
 101/*
 102 * Vendor specific requests to read/write data
 103 */
 104#define REQUEST_REGISTER        ((u8)0x10)
 105#define REQUEST_EEPROM          ((u8)0x11)
 106
 107static int
 108nc_vendor_read(struct usbnet *dev, u8 req, u8 regnum, u16 *retval_ptr)
 109{
 110        int status = usbnet_read_cmd(dev, req,
 111                                     USB_DIR_IN | USB_TYPE_VENDOR |
 112                                     USB_RECIP_DEVICE,
 113                                     0, regnum, retval_ptr,
 114                                     sizeof *retval_ptr);
 115        if (status > 0)
 116                status = 0;
 117        if (!status)
 118                le16_to_cpus(retval_ptr);
 119        return status;
 120}
 121
 122static inline int
 123nc_register_read(struct usbnet *dev, u8 regnum, u16 *retval_ptr)
 124{
 125        return nc_vendor_read(dev, REQUEST_REGISTER, regnum, retval_ptr);
 126}
 127
 128// no retval ... can become async, usable in_interrupt()
 129static void
 130nc_vendor_write(struct usbnet *dev, u8 req, u8 regnum, u16 value)
 131{
 132        usbnet_write_cmd(dev, req,
 133                         USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 134                         value, regnum, NULL, 0);
 135}
 136
 137static inline void
 138nc_register_write(struct usbnet *dev, u8 regnum, u16 value)
 139{
 140        nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
 141}
 142
 143
 144#if 0
 145static void nc_dump_registers(struct usbnet *dev)
 146{
 147        u8      reg;
 148        u16     *vp = kmalloc(sizeof (u16));
 149
 150        if (!vp)
 151                return;
 152
 153        netdev_dbg(dev->net, "registers:\n");
 154        for (reg = 0; reg < 0x20; reg++) {
 155                int retval;
 156
 157                // reading some registers is trouble
 158                if (reg >= 0x08 && reg <= 0xf)
 159                        continue;
 160                if (reg >= 0x12 && reg <= 0x1e)
 161                        continue;
 162
 163                retval = nc_register_read(dev, reg, vp);
 164                if (retval < 0)
 165                        netdev_dbg(dev->net, "reg [0x%x] ==> error %d\n",
 166                                   reg, retval);
 167                else
 168                        netdev_dbg(dev->net, "reg [0x%x] = 0x%x\n", reg, *vp);
 169        }
 170        kfree(vp);
 171}
 172#endif
 173
 174
 175/*-------------------------------------------------------------------------*/
 176
 177/*
 178 * Control register
 179 */
 180
 181#define USBCTL_WRITABLE_MASK    0x1f0f
 182// bits 15-13 reserved, r/o
 183#define USBCTL_ENABLE_LANG      (1 << 12)
 184#define USBCTL_ENABLE_MFGR      (1 << 11)
 185#define USBCTL_ENABLE_PROD      (1 << 10)
 186#define USBCTL_ENABLE_SERIAL    (1 << 9)
 187#define USBCTL_ENABLE_DEFAULTS  (1 << 8)
 188// bits 7-4 reserved, r/o
 189#define USBCTL_FLUSH_OTHER      (1 << 3)
 190#define USBCTL_FLUSH_THIS       (1 << 2)
 191#define USBCTL_DISCONN_OTHER    (1 << 1)
 192#define USBCTL_DISCONN_THIS     (1 << 0)
 193
 194static inline void nc_dump_usbctl(struct usbnet *dev, u16 usbctl)
 195{
 196        netif_dbg(dev, link, dev->net,
 197                  "net1080 %s-%s usbctl 0x%x:%s%s%s%s%s; this%s%s; other%s%s; r/o 0x%x\n",
 198                  dev->udev->bus->bus_name, dev->udev->devpath,
 199                  usbctl,
 200                  (usbctl & USBCTL_ENABLE_LANG) ? " lang" : "",
 201                  (usbctl & USBCTL_ENABLE_MFGR) ? " mfgr" : "",
 202                  (usbctl & USBCTL_ENABLE_PROD) ? " prod" : "",
 203                  (usbctl & USBCTL_ENABLE_SERIAL) ? " serial" : "",
 204                  (usbctl & USBCTL_ENABLE_DEFAULTS) ? " defaults" : "",
 205
 206                  (usbctl & USBCTL_FLUSH_THIS) ? " FLUSH" : "",
 207                  (usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",
 208
 209                  (usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
 210                  (usbctl & USBCTL_DISCONN_OTHER) ? " DIS" : "",
 211
 212                  usbctl & ~USBCTL_WRITABLE_MASK);
 213}
 214
 215/*-------------------------------------------------------------------------*/
 216
 217/*
 218 * Status register
 219 */
 220
 221#define STATUS_PORT_A           (1 << 15)
 222
 223#define STATUS_CONN_OTHER       (1 << 14)
 224#define STATUS_SUSPEND_OTHER    (1 << 13)
 225#define STATUS_MAILBOX_OTHER    (1 << 12)
 226#define STATUS_PACKETS_OTHER(n) (((n) >> 8) & 0x03)
 227
 228#define STATUS_CONN_THIS        (1 << 6)
 229#define STATUS_SUSPEND_THIS     (1 << 5)
 230#define STATUS_MAILBOX_THIS     (1 << 4)
 231#define STATUS_PACKETS_THIS(n)  (((n) >> 0) & 0x03)
 232
 233#define STATUS_UNSPEC_MASK      0x0c8c
 234#define STATUS_NOISE_MASK       ((u16)~(0x0303|STATUS_UNSPEC_MASK))
 235
 236
 237static inline void nc_dump_status(struct usbnet *dev, u16 status)
 238{
 239        netif_dbg(dev, link, dev->net,
 240                  "net1080 %s-%s status 0x%x: this (%c) PKT=%d%s%s%s; other PKT=%d%s%s%s; unspec 0x%x\n",
 241                  dev->udev->bus->bus_name, dev->udev->devpath,
 242                  status,
 243
 244                  // XXX the packet counts don't seem right
 245                  // (1 at reset, not 0); maybe UNSPEC too
 246
 247                  (status & STATUS_PORT_A) ? 'A' : 'B',
 248                  STATUS_PACKETS_THIS(status),
 249                  (status & STATUS_CONN_THIS) ? " CON" : "",
 250                  (status & STATUS_SUSPEND_THIS) ? " SUS" : "",
 251                  (status & STATUS_MAILBOX_THIS) ? " MBOX" : "",
 252
 253                  STATUS_PACKETS_OTHER(status),
 254                  (status & STATUS_CONN_OTHER) ? " CON" : "",
 255                  (status & STATUS_SUSPEND_OTHER) ? " SUS" : "",
 256                  (status & STATUS_MAILBOX_OTHER) ? " MBOX" : "",
 257
 258                  status & STATUS_UNSPEC_MASK);
 259}
 260
 261/*-------------------------------------------------------------------------*/
 262
 263/*
 264 * TTL register
 265 */
 266
 267#define TTL_THIS(ttl)   (0x00ff & ttl)
 268#define TTL_OTHER(ttl)  (0x00ff & (ttl >> 8))
 269#define MK_TTL(this,other)      ((u16)(((other)<<8)|(0x00ff&(this))))
 270
 271static inline void nc_dump_ttl(struct usbnet *dev, u16 ttl)
 272{
 273        netif_dbg(dev, link, dev->net, "net1080 %s-%s ttl 0x%x this = %d, other = %d\n",
 274                  dev->udev->bus->bus_name, dev->udev->devpath,
 275                  ttl, TTL_THIS(ttl), TTL_OTHER(ttl));
 276}
 277
 278/*-------------------------------------------------------------------------*/
 279
 280static int net1080_reset(struct usbnet *dev)
 281{
 282        u16             usbctl, status, ttl;
 283        u16             vp;
 284        int             retval;
 285
 286        // nc_dump_registers(dev);
 287
 288        if ((retval = nc_register_read(dev, REG_STATUS, &vp)) < 0) {
 289                netdev_dbg(dev->net, "can't read %s-%s status: %d\n",
 290                           dev->udev->bus->bus_name, dev->udev->devpath, retval);
 291                goto done;
 292        }
 293        status = vp;
 294        nc_dump_status(dev, status);
 295
 296        if ((retval = nc_register_read(dev, REG_USBCTL, &vp)) < 0) {
 297                netdev_dbg(dev->net, "can't read USBCTL, %d\n", retval);
 298                goto done;
 299        }
 300        usbctl = vp;
 301        nc_dump_usbctl(dev, usbctl);
 302
 303        nc_register_write(dev, REG_USBCTL,
 304                        USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
 305
 306        if ((retval = nc_register_read(dev, REG_TTL, &vp)) < 0) {
 307                netdev_dbg(dev->net, "can't read TTL, %d\n", retval);
 308                goto done;
 309        }
 310        ttl = vp;
 311        // nc_dump_ttl(dev, ttl);
 312
 313        nc_register_write(dev, REG_TTL,
 314                        MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
 315        netdev_dbg(dev->net, "assigned TTL, %d ms\n", NC_READ_TTL_MS);
 316
 317        netif_info(dev, link, dev->net, "port %c, peer %sconnected\n",
 318                   (status & STATUS_PORT_A) ? 'A' : 'B',
 319                   (status & STATUS_CONN_OTHER) ? "" : "dis");
 320        retval = 0;
 321
 322done:
 323        return retval;
 324}
 325
 326static int net1080_check_connect(struct usbnet *dev)
 327{
 328        int                     retval;
 329        u16                     status;
 330        u16                     vp;
 331
 332        retval = nc_register_read(dev, REG_STATUS, &vp);
 333        status = vp;
 334        if (retval != 0) {
 335                netdev_dbg(dev->net, "net1080_check_conn read - %d\n", retval);
 336                return retval;
 337        }
 338        if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
 339                return -ENOLINK;
 340        return 0;
 341}
 342
 343static void nc_ensure_sync(struct usbnet *dev)
 344{
 345        if (++dev->frame_errors <= 5)
 346                return;
 347
 348        if (usbnet_write_cmd_async(dev, REQUEST_REGISTER,
 349                                        USB_DIR_OUT | USB_TYPE_VENDOR |
 350                                        USB_RECIP_DEVICE,
 351                                        USBCTL_FLUSH_THIS |
 352                                        USBCTL_FLUSH_OTHER,
 353                                        REG_USBCTL, NULL, 0))
 354                return;
 355
 356        netif_dbg(dev, rx_err, dev->net,
 357                  "flush net1080; too many framing errors\n");
 358        dev->frame_errors = 0;
 359}
 360
 361static int net1080_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 362{
 363        struct nc_header        *header;
 364        struct nc_trailer       *trailer;
 365        u16                     hdr_len, packet_len;
 366
 367        /* This check is no longer done by usbnet */
 368        if (skb->len < dev->net->hard_header_len)
 369                return 0;
 370
 371        if (!(skb->len & 0x01)) {
 372                netdev_dbg(dev->net, "rx framesize %d range %d..%d mtu %d\n",
 373                           skb->len, dev->net->hard_header_len, dev->hard_mtu,
 374                           dev->net->mtu);
 375                dev->net->stats.rx_frame_errors++;
 376                nc_ensure_sync(dev);
 377                return 0;
 378        }
 379
 380        header = (struct nc_header *) skb->data;
 381        hdr_len = le16_to_cpup(&header->hdr_len);
 382        packet_len = le16_to_cpup(&header->packet_len);
 383        if (FRAMED_SIZE(packet_len) > NC_MAX_PACKET) {
 384                dev->net->stats.rx_frame_errors++;
 385                netdev_dbg(dev->net, "packet too big, %d\n", packet_len);
 386                nc_ensure_sync(dev);
 387                return 0;
 388        } else if (hdr_len < MIN_HEADER) {
 389                dev->net->stats.rx_frame_errors++;
 390                netdev_dbg(dev->net, "header too short, %d\n", hdr_len);
 391                nc_ensure_sync(dev);
 392                return 0;
 393        } else if (hdr_len > MIN_HEADER) {
 394                // out of band data for us?
 395                netdev_dbg(dev->net, "header OOB, %d bytes\n", hdr_len - MIN_HEADER);
 396                nc_ensure_sync(dev);
 397                // switch (vendor/product ids) { ... }
 398        }
 399        skb_pull(skb, hdr_len);
 400
 401        trailer = (struct nc_trailer *)
 402                (skb->data + skb->len - sizeof *trailer);
 403        skb_trim(skb, skb->len - sizeof *trailer);
 404
 405        if ((packet_len & 0x01) == 0) {
 406                if (skb->data [packet_len] != PAD_BYTE) {
 407                        dev->net->stats.rx_frame_errors++;
 408                        netdev_dbg(dev->net, "bad pad\n");
 409                        return 0;
 410                }
 411                skb_trim(skb, skb->len - 1);
 412        }
 413        if (skb->len != packet_len) {
 414                dev->net->stats.rx_frame_errors++;
 415                netdev_dbg(dev->net, "bad packet len %d (expected %d)\n",
 416                           skb->len, packet_len);
 417                nc_ensure_sync(dev);
 418                return 0;
 419        }
 420        if (header->packet_id != get_unaligned(&trailer->packet_id)) {
 421                dev->net->stats.rx_fifo_errors++;
 422                netdev_dbg(dev->net, "(2+ dropped) rx packet_id mismatch 0x%x 0x%x\n",
 423                           le16_to_cpu(header->packet_id),
 424                           le16_to_cpu(trailer->packet_id));
 425                return 0;
 426        }
 427#if 0
 428        netdev_dbg(dev->net, "frame <rx h %d p %d id %d\n", header->hdr_len,
 429                   header->packet_len, header->packet_id);
 430#endif
 431        dev->frame_errors = 0;
 432        return 1;
 433}
 434
 435static struct sk_buff *
 436net1080_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 437{
 438        struct sk_buff          *skb2;
 439        struct nc_header        *header = NULL;
 440        struct nc_trailer       *trailer = NULL;
 441        int                     padlen = sizeof (struct nc_trailer);
 442        int                     len = skb->len;
 443
 444        if (!((len + padlen + sizeof (struct nc_header)) & 0x01))
 445                padlen++;
 446        if (!skb_cloned(skb)) {
 447                int     headroom = skb_headroom(skb);
 448                int     tailroom = skb_tailroom(skb);
 449
 450                if (padlen <= tailroom &&
 451                    sizeof(struct nc_header) <= headroom)
 452                        /* There's enough head and tail room */
 453                        goto encapsulate;
 454
 455                if ((sizeof (struct nc_header) + padlen) <
 456                                (headroom + tailroom)) {
 457                        /* There's enough total room, so just readjust */
 458                        skb->data = memmove(skb->head
 459                                                + sizeof (struct nc_header),
 460                                            skb->data, skb->len);
 461                        skb_set_tail_pointer(skb, len);
 462                        goto encapsulate;
 463                }
 464        }
 465
 466        /* Create a new skb to use with the correct size */
 467        skb2 = skb_copy_expand(skb,
 468                                sizeof (struct nc_header),
 469                                padlen,
 470                                flags);
 471        dev_kfree_skb_any(skb);
 472        if (!skb2)
 473                return skb2;
 474        skb = skb2;
 475
 476encapsulate:
 477        /* header first */
 478        header = (struct nc_header *) skb_push(skb, sizeof *header);
 479        header->hdr_len = cpu_to_le16(sizeof (*header));
 480        header->packet_len = cpu_to_le16(len);
 481        header->packet_id = cpu_to_le16((u16)dev->xid++);
 482
 483        /* maybe pad; then trailer */
 484        if (!((skb->len + sizeof *trailer) & 0x01))
 485                *skb_put(skb, 1) = PAD_BYTE;
 486        trailer = (struct nc_trailer *) skb_put(skb, sizeof *trailer);
 487        put_unaligned(header->packet_id, &trailer->packet_id);
 488#if 0
 489        netdev_dbg(dev->net, "frame >tx h %d p %d id %d\n",
 490                   header->hdr_len, header->packet_len,
 491                   header->packet_id);
 492#endif
 493        return skb;
 494}
 495
 496static int net1080_bind(struct usbnet *dev, struct usb_interface *intf)
 497{
 498        unsigned        extra = sizeof (struct nc_header)
 499                                + 1
 500                                + sizeof (struct nc_trailer);
 501
 502        dev->net->hard_header_len += extra;
 503        dev->rx_urb_size = dev->net->hard_header_len + dev->net->mtu;
 504        dev->hard_mtu = NC_MAX_PACKET;
 505        return usbnet_get_endpoints (dev, intf);
 506}
 507
 508static const struct driver_info net1080_info = {
 509        .description =  "NetChip TurboCONNECT",
 510        .flags =        FLAG_POINTTOPOINT | FLAG_FRAMING_NC,
 511        .bind =         net1080_bind,
 512        .reset =        net1080_reset,
 513        .check_connect = net1080_check_connect,
 514        .rx_fixup =     net1080_rx_fixup,
 515        .tx_fixup =     net1080_tx_fixup,
 516};
 517
 518static const struct usb_device_id       products [] = {
 519{
 520        USB_DEVICE(0x0525, 0x1080),     // NetChip ref design
 521        .driver_info =  (unsigned long) &net1080_info,
 522}, {
 523        USB_DEVICE(0x06D0, 0x0622),     // Laplink Gold
 524        .driver_info =  (unsigned long) &net1080_info,
 525},
 526        { },            // END
 527};
 528MODULE_DEVICE_TABLE(usb, products);
 529
 530static struct usb_driver net1080_driver = {
 531        .name =         "net1080",
 532        .id_table =     products,
 533        .probe =        usbnet_probe,
 534        .disconnect =   usbnet_disconnect,
 535        .suspend =      usbnet_suspend,
 536        .resume =       usbnet_resume,
 537        .disable_hub_initiated_lpm = 1,
 538};
 539
 540module_usb_driver(net1080_driver);
 541
 542MODULE_AUTHOR("David Brownell");
 543MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
 544MODULE_LICENSE("GPL");
 545