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
 116static void
 117nc_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
 124static inline void
 125nc_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
 132static 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
 181static 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
 224static 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
 259static 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
 300done:
 301        return retval;
 302}
 303
 304static 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
 321static 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
 339static 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
 413static struct sk_buff *
 414net1080_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
 454encapsulate:
 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
 474static 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
 486static 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
 496static 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};
 506MODULE_DEVICE_TABLE(usb, products);
 507
 508static 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
 518module_usb_driver(net1080_driver);
 519
 520MODULE_AUTHOR("David Brownell");
 521MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
 522MODULE_LICENSE("GPL");
 523