linux/drivers/net/usb/net1080.c
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   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
  44struct 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
  57struct 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
  95static int
  96nc_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
 110static inline int
 111nc_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()
 117static void
 118nc_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
 125static inline void
 126nc_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
 133static 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
 182static 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
 225static 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
 260static 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
 301done:
 302        return retval;
 303}
 304
 305static 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
 322static 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
 340static 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
 414static struct sk_buff *
 415net1080_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
 455encapsulate:
 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
 475static 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
 487static 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
 497static 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};
 507MODULE_DEVICE_TABLE(usb, products);
 508
 509static 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
 519module_usb_driver(net1080_driver);
 520
 521MODULE_AUTHOR("David Brownell");
 522MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
 523MODULE_LICENSE("GPL");
 524