drivers/net/arcnet/arcnet.c

   1 /*
   2  * Linux ARCnet driver - device-independent routines
   3  *
   4  * Written 1997 by David Woodhouse.
   5  * Written 1994-1999 by Avery Pennarun.
   6  * Written 1999-2000 by Martin Mares <[email protected]>.
   7  * Derived from skeleton.c by Donald Becker.
   8  *
   9  * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
  10  *  for sponsoring the further development of this driver.
  11  *
  12  * **********************
  13  *
  14  * The original copyright was as follows:
  15  *
  16  * skeleton.c Written 1993 by Donald Becker.
  17  * Copyright 1993 United States Government as represented by the
  18  * Director, National Security Agency.  This software may only be used
  19  * and distributed according to the terms of the GNU General Public License as
  20  * modified by SRC, incorporated herein by reference.
  21  *
  22  * **********************
  23  *
  24  * The change log is now in a file called ChangeLog in this directory.
  25  *
  26  * Sources:
  27  *  - Crynwr arcnet.com/arcether.com packet drivers.
  28  *  - arcnet.c v0.00 dated 1/1/94 and apparently by
  29  *     Donald Becker - it didn't work :)
  30  *  - skeleton.c v0.05 dated 11/16/93 by Donald Becker
  31  *     (from Linux Kernel 1.1.45)
  32  *  - RFC's 1201 and 1051 - re: TCP/IP over ARCnet
  33  *  - The official ARCnet COM9026 data sheets (!) thanks to
  34  *     Ken Cornetet <[email protected]>
  35  *  - The official ARCnet COM20020 data sheets.
  36  *  - Information on some more obscure ARCnet controller chips, thanks
  37  *     to the nice people at SMSC.
  38  *  - net/inet/eth.c (from kernel 1.1.50) for header-building info.
  39  *  - Alternate Linux ARCnet source by V.Shergin <[email protected]>
  40  *  - Textual information and more alternate source from Joachim Koenig
  41  *     <[email protected]>
  42  */
  43
  44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  45
  46 #include <linux/module.h>
  47 #include <linux/types.h>
  48 #include <linux/delay.h>
  49 #include <linux/netdevice.h>
  50 #include <linux/if_arp.h>
  51 #include <net/arp.h>
  52 #include <linux/init.h>
  53 #include <linux/jiffies.h>
  54 #include <linux/errqueue.h>
  55
  56 #include <linux/leds.h>
  57 #include <linux/workqueue.h>
  58
  59 #include "arcdevice.h"
  60 #include "com9026.h"
  61
  62 /* "do nothing" functions for protocol drivers */
  63 static void null_rx(struct net_device *dev, int bufnum,
  64                     struct archdr *pkthdr, int length);
  65 static int null_build_header(struct sk_buff *skb, struct net_device *dev,
  66                              unsigned short type, uint8_t daddr);
  67 static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
  68                            int length, int bufnum);
  69
  70 static void arcnet_rx(struct net_device *dev, int bufnum);
  71
  72 /* one ArcProto per possible proto ID.  None of the elements of
  73  * arc_proto_map are allowed to be NULL; they will get set to
  74  * arc_proto_default instead.  It also must not be NULL; if you would like
  75  * to set it to NULL, set it to &arc_proto_null instead.
  76  */
  77 struct ArcProto *arc_proto_map[256];
  78 EXPORT_SYMBOL(arc_proto_map);
  79
  80 struct ArcProto *arc_proto_default;
  81 EXPORT_SYMBOL(arc_proto_default);
  82
  83 struct ArcProto *arc_bcast_proto;
  84 EXPORT_SYMBOL(arc_bcast_proto);
  85
  86 struct ArcProto *arc_raw_proto;
  87 EXPORT_SYMBOL(arc_raw_proto);
  88
  89 static struct ArcProto arc_proto_null = {
  90         .suffix         = '?',
  91         .mtu            = XMTU,
  92         .is_ip          = 0,
  93         .rx             = null_rx,
  94         .build_header   = null_build_header,
  95         .prepare_tx     = null_prepare_tx,
  96         .continue_tx    = NULL,
  97         .ack_tx         = NULL
  98 };
  99
 100 /* Exported function prototypes */
 101 int arcnet_debug = ARCNET_DEBUG;
 102 EXPORT_SYMBOL(arcnet_debug);
 103
 104 /* Internal function prototypes */
 105 static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
 106                          unsigned short type, const void *daddr,
 107                          const void *saddr, unsigned len);
 108 static int go_tx(struct net_device *dev);
 109
 110 static int debug = ARCNET_DEBUG;
 111 module_param(debug, int, 0);
 112 MODULE_DESCRIPTION("ARCnet core driver");
 113 MODULE_LICENSE("GPL");
 114
 115 static int __init arcnet_init(void)
 116 {
 117         int count;
 118
 119         arcnet_debug = debug;
 120
 121         pr_info("arcnet loaded\n");
 122
 123         /* initialize the protocol map */
 124         arc_raw_proto = arc_proto_default = arc_bcast_proto = &arc_proto_null;
 125         for (count = 0; count < 256; count++)
 126                 arc_proto_map[count] = arc_proto_default;
 127
 128         if (BUGLVL(D_DURING))
 129                 pr_info("struct sizes: %zd %zd %zd %zd %zd\n",
 130                         sizeof(struct arc_hardware),
 131                         sizeof(struct arc_rfc1201),
 132                         sizeof(struct arc_rfc1051),
 133                         sizeof(struct arc_eth_encap),
 134                         sizeof(struct archdr));
 135
 136         return 0;
 137 }
 138
 139 static void __exit arcnet_exit(void)
 140 {
 141 }
 142
 143 module_init(arcnet_init);
 144 module_exit(arcnet_exit);
 145
 146 /* Dump the contents of an sk_buff */
 147 #if ARCNET_DEBUG_MAX & D_SKB
 148 void arcnet_dump_skb(struct net_device *dev,
 149                      struct sk_buff *skb, char *desc)
 150 {
 151         char hdr[32];
 152
 153         /* dump the packet */
 154         snprintf(hdr, sizeof(hdr), "%6s:%s skb->data:", dev->name, desc);
 155         print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
 156                        16, 1, skb->data, skb->len, true);
 157 }
 158 EXPORT_SYMBOL(arcnet_dump_skb);
 159 #endif
 160
 161 /* Dump the contents of an ARCnet buffer */
 162 #if (ARCNET_DEBUG_MAX & (D_RX | D_TX))
 163 static void arcnet_dump_packet(struct net_device *dev, int bufnum,
 164                                char *desc, int take_arcnet_lock)
 165 {
 166         struct arcnet_local *lp = netdev_priv(dev);
 167         int i, length;
 168         unsigned long flags = 0;
 169         static uint8_t buf[512];
 170         char hdr[32];
 171
 172         /* hw.copy_from_card expects IRQ context so take the IRQ lock
 173          * to keep it single threaded
 174          */
 175         if (take_arcnet_lock)
 176                 spin_lock_irqsave(&lp->lock, flags);
 177
 178         lp->hw.copy_from_card(dev, bufnum, 0, buf, 512);
 179         if (take_arcnet_lock)
 180                 spin_unlock_irqrestore(&lp->lock, flags);
 181
 182         /* if the offset[0] byte is nonzero, this is a 256-byte packet */
 183         length = (buf[2] ? 256 : 512);
 184
 185         /* dump the packet */
 186         snprintf(hdr, sizeof(hdr), "%6s:%s packet dump:", dev->name, desc);
 187         print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
 188                        16, 1, buf, length, true);
 189 }
 190
 191 #else
 192
 193 #define arcnet_dump_packet(dev, bufnum, desc, take_arcnet_lock) do { } while (0)
 194
 195 #endif
 196
 197 /* Trigger a LED event in response to a ARCNET device event */
 198 void arcnet_led_event(struct net_device *dev, enum arcnet_led_event event)
 199 {
 200         struct arcnet_local *lp = netdev_priv(dev);
 201
 202         switch (event) {
 203         case ARCNET_LED_EVENT_RECON:
 204                 led_trigger_blink_oneshot(lp->recon_led_trig, 350, 350, 0);
 205                 break;
 206         case ARCNET_LED_EVENT_OPEN:
 207                 led_trigger_event(lp->tx_led_trig, LED_OFF);
 208                 led_trigger_event(lp->recon_led_trig, LED_OFF);
 209                 break;
 210         case ARCNET_LED_EVENT_STOP:
 211                 led_trigger_event(lp->tx_led_trig, LED_OFF);
 212                 led_trigger_event(lp->recon_led_trig, LED_OFF);
 213                 break;
 214         case ARCNET_LED_EVENT_TX:
 215                 led_trigger_blink_oneshot(lp->tx_led_trig, 50, 50, 0);
 216                 break;
 217         }
 218 }
 219 EXPORT_SYMBOL_GPL(arcnet_led_event);
 220
 221 static void arcnet_led_release(struct device *gendev, void *res)
 222 {
 223         struct arcnet_local *lp = netdev_priv(to_net_dev(gendev));
 224
 225         led_trigger_unregister_simple(lp->tx_led_trig);
 226         led_trigger_unregister_simple(lp->recon_led_trig);
 227 }
 228
 229 /* Register ARCNET LED triggers for a arcnet device
 230  *
 231  * This is normally called from a driver's probe function
 232  */
 233 void devm_arcnet_led_init(struct net_device *netdev, int index, int subid)
 234 {
 235         struct arcnet_local *lp = netdev_priv(netdev);
 236         void *res;
 237
 238         res = devres_alloc(arcnet_led_release, 0, GFP_KERNEL);
 239         if (!res) {
 240                 netdev_err(netdev, "cannot register LED triggers\n");
 241                 return;
 242         }
 243
 244         snprintf(lp->tx_led_trig_name, sizeof(lp->tx_led_trig_name),
 245                  "arc%d-%d-tx", index, subid);
 246         snprintf(lp->recon_led_trig_name, sizeof(lp->recon_led_trig_name),
 247                  "arc%d-%d-recon", index, subid);
 248
 249         led_trigger_register_simple(lp->tx_led_trig_name,
 250                                     &lp->tx_led_trig);
 251         led_trigger_register_simple(lp->recon_led_trig_name,
 252                                     &lp->recon_led_trig);
 253
 254         devres_add(&netdev->dev, res);
 255 }
 256 EXPORT_SYMBOL_GPL(devm_arcnet_led_init);
 257
 258 /* Unregister a protocol driver from the arc_proto_map.  Protocol drivers
 259  * are responsible for registering themselves, but the unregister routine
 260  * is pretty generic so we'll do it here.
 261  */
 262 void arcnet_unregister_proto(struct ArcProto *proto)
 263 {
 264         int count;
 265
 266         if (arc_proto_default == proto)
 267                 arc_proto_default = &arc_proto_null;
 268         if (arc_bcast_proto == proto)
 269                 arc_bcast_proto = arc_proto_default;
 270         if (arc_raw_proto == proto)
 271                 arc_raw_proto = arc_proto_default;
 272
 273         for (count = 0; count < 256; count++) {
 274                 if (arc_proto_map[count] == proto)
 275                         arc_proto_map[count] = arc_proto_default;
 276         }
 277 }
 278 EXPORT_SYMBOL(arcnet_unregister_proto);
 279
 280 /* Add a buffer to the queue.  Only the interrupt handler is allowed to do
 281  * this, unless interrupts are disabled.
 282  *
 283  * Note: we don't check for a full queue, since there aren't enough buffers
 284  * to more than fill it.
 285  */
 286 static void release_arcbuf(struct net_device *dev, int bufnum)
 287 {
 288         struct arcnet_local *lp = netdev_priv(dev);
 289         int i;
 290
 291         lp->buf_queue[lp->first_free_buf++] = bufnum;
 292         lp->first_free_buf %= 5;
 293
 294         if (BUGLVL(D_DURING)) {
 295                 arc_printk(D_DURING, dev, "release_arcbuf: freed #%d; buffer queue is now: ",
 296                            bufnum);
 297                 for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)
 298                         arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
 299                 arc_cont(D_DURING, "\n");
 300         }
 301 }
 302
 303 /* Get a buffer from the queue.
 304  * If this returns -1, there are no buffers available.
 305  */
 306 static int get_arcbuf(struct net_device *dev)
 307 {
 308         struct arcnet_local *lp = netdev_priv(dev);
 309         int buf = -1, i;
 310
 311         if (!atomic_dec_and_test(&lp->buf_lock)) {
 312                 /* already in this function */
 313                 arc_printk(D_NORMAL, dev, "get_arcbuf: overlap (%d)!\n",
 314                            lp->buf_lock.counter);
 315         } else {                        /* we can continue */
 316                 if (lp->next_buf >= 5)
 317                         lp->next_buf -= 5;
 318
 319                 if (lp->next_buf == lp->first_free_buf) {
 320                         arc_printk(D_NORMAL, dev, "get_arcbuf: BUG: no buffers are available??\n");
 321                 } else {
 322                         buf = lp->buf_queue[lp->next_buf++];
 323                         lp->next_buf %= 5;
 324                 }
 325         }
 326
 327         if (BUGLVL(D_DURING)) {
 328                 arc_printk(D_DURING, dev, "get_arcbuf: got #%d; buffer queue is now: ",
 329                            buf);
 330                 for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)
 331                         arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
 332                 arc_cont(D_DURING, "\n");
 333         }
 334
 335         atomic_inc(&lp->buf_lock);
 336         return buf;
 337 }
 338
 339 static int choose_mtu(void)
 340 {
 341         int count, mtu = 65535;
 342
 343         /* choose the smallest MTU of all available encaps */
 344         for (count = 0; count < 256; count++) {
 345                 if (arc_proto_map[count] != &arc_proto_null &&
 346                     arc_proto_map[count]->mtu < mtu) {
 347                         mtu = arc_proto_map[count]->mtu;
 348                 }
 349         }
 350
 351         return mtu == 65535 ? XMTU : mtu;
 352 }
 353
 354 static const struct header_ops arcnet_header_ops = {
 355         .create = arcnet_header,
 356 };
 357
 358 static const struct net_device_ops arcnet_netdev_ops = {
 359         .ndo_open       = arcnet_open,
 360         .ndo_stop       = arcnet_close,
 361         .ndo_start_xmit = arcnet_send_packet,
 362         .ndo_tx_timeout = arcnet_timeout,
 363 };
 364
 365 /* Setup a struct device for ARCnet. */
 366 static void arcdev_setup(struct net_device *dev)
 367 {
 368         dev->type = ARPHRD_ARCNET;
 369         dev->netdev_ops = &arcnet_netdev_ops;
 370         dev->header_ops = &arcnet_header_ops;
 371         dev->hard_header_len = sizeof(struct arc_hardware);
 372         dev->mtu = choose_mtu();
 373
 374         dev->addr_len = ARCNET_ALEN;
 375         dev->tx_queue_len = 100;
 376         dev->broadcast[0] = 0x00;       /* for us, broadcasts are address 0 */
 377         dev->watchdog_timeo = TX_TIMEOUT;
 378
 379         /* New-style flags. */
 380         dev->flags = IFF_BROADCAST;
 381 }
 382
 383 static void arcnet_timer(struct timer_list *t)
 384 {
 385         struct arcnet_local *lp = from_timer(lp, t, timer);
 386         struct net_device *dev = lp->dev;
 387
 388         spin_lock_irq(&lp->lock);
 389
 390         if (!lp->reset_in_progress && !netif_carrier_ok(dev)) {
 391                 netif_carrier_on(dev);
 392                 netdev_info(dev, "link up\n");
 393         }
 394
 395         spin_unlock_irq(&lp->lock);
 396 }
 397
 398 static void reset_device_work(struct work_struct *work)
 399 {
 400         struct arcnet_local *lp;
 401         struct net_device *dev;
 402
 403         lp = container_of(work, struct arcnet_local, reset_work);
 404         dev = lp->dev;
 405
 406         /* Do not bring the network interface back up if an ifdown
 407          * was already done.
 408          */
 409         if (!netif_running(dev) || !lp->reset_in_progress)
 410                 return;
 411
 412         rtnl_lock();
 413
 414         /* Do another check, in case of an ifdown that was triggered in
 415          * the small race window between the exit condition above and
 416          * acquiring RTNL.
 417          */
 418         if (!netif_running(dev) || !lp->reset_in_progress)
 419                 goto out;
 420
 421         dev_close(dev);
 422         dev_open(dev, NULL);
 423
 424 out:
 425         rtnl_unlock();
 426 }
 427
 428 static void arcnet_reply_work(struct work_struct *t)
 429 {
 430         struct arcnet_local *lp = from_work(lp, t, reply_work);
 431
 432         struct sk_buff *ackskb, *skb;
 433         struct sock_exterr_skb *serr;
 434         struct sock *sk;
 435         int ret;
 436
 437         local_irq_disable();
 438         skb = lp->outgoing.skb;
 439         if (!skb || !skb->sk) {
 440                 local_irq_enable();
 441                 return;
 442         }
 443
 444         sock_hold(skb->sk);
 445         sk = skb->sk;
 446         ackskb = skb_clone_sk(skb);
 447         sock_put(skb->sk);
 448
 449         if (!ackskb) {
 450                 local_irq_enable();
 451                 return;
 452         }
 453
 454         serr = SKB_EXT_ERR(ackskb);
 455         memset(serr, 0, sizeof(*serr));
 456         serr->ee.ee_errno = ENOMSG;
 457         serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
 458         serr->ee.ee_data = skb_shinfo(skb)->tskey;
 459         serr->ee.ee_info = lp->reply_status;
 460
 461         /* finally erasing outgoing skb */
 462         dev_kfree_skb(lp->outgoing.skb);
 463         lp->outgoing.skb = NULL;
 464
 465         ackskb->dev = lp->dev;
 466
 467         ret = sock_queue_err_skb(sk, ackskb);
 468         if (ret)
 469                 dev_kfree_skb_irq(ackskb);
 470
 471         local_irq_enable();
 472 };
 473
 474 struct net_device *alloc_arcdev(const char *name)
 475 {
 476         struct net_device *dev;
 477
 478         dev = alloc_netdev(sizeof(struct arcnet_local),
 479                            name && *name ? name : "arc%d", NET_NAME_UNKNOWN,
 480                            arcdev_setup);
 481         if (dev) {
 482                 struct arcnet_local *lp = netdev_priv(dev);
 483
 484                 lp->dev = dev;
 485                 spin_lock_init(&lp->lock);
 486                 timer_setup(&lp->timer, arcnet_timer, 0);
 487                 INIT_WORK(&lp->reset_work, reset_device_work);
 488         }
 489
 490         return dev;
 491 }
 492 EXPORT_SYMBOL(alloc_arcdev);
 493
 494 void free_arcdev(struct net_device *dev)
 495 {
 496         struct arcnet_local *lp = netdev_priv(dev);
 497
 498         /* Do not cancel this at ->ndo_close(), as the workqueue itself
 499          * indirectly calls the ifdown path through dev_close().
 500          */
 501         cancel_work_sync(&lp->reset_work);
 502         free_netdev(dev);
 503 }
 504 EXPORT_SYMBOL(free_arcdev);
 505
 506 /* Open/initialize the board.  This is called sometime after booting when
 507  * the 'ifconfig' program is run.
 508  *
 509  * This routine should set everything up anew at each open, even registers
 510  * that "should" only need to be set once at boot, so that there is
 511  * non-reboot way to recover if something goes wrong.
 512  */
 513 int arcnet_open(struct net_device *dev)
 514 {
 515         struct arcnet_local *lp = netdev_priv(dev);
 516         int count, newmtu, error;
 517
 518         arc_printk(D_INIT, dev, "opened.");
 519
 520         if (!try_module_get(lp->hw.owner))
 521                 return -ENODEV;
 522
 523         if (BUGLVL(D_PROTO)) {
 524                 arc_printk(D_PROTO, dev, "protocol map (default is '%c'): ",
 525                            arc_proto_default->suffix);
 526                 for (count = 0; count < 256; count++)
 527                         arc_cont(D_PROTO, "%c", arc_proto_map[count]->suffix);
 528                 arc_cont(D_PROTO, "\n");
 529         }
 530
 531         INIT_WORK(&lp->reply_work, arcnet_reply_work);
 532
 533         arc_printk(D_INIT, dev, "arcnet_open: resetting card.\n");
 534
 535         /* try to put the card in a defined state - if it fails the first
 536          * time, actually reset it.
 537          */
 538         error = -ENODEV;
 539         if (lp->hw.reset(dev, 0) && lp->hw.reset(dev, 1))
 540                 goto out_module_put;
 541
 542         newmtu = choose_mtu();
 543         if (newmtu < dev->mtu)
 544                 dev->mtu = newmtu;
 545
 546         arc_printk(D_INIT, dev, "arcnet_open: mtu: %d.\n", dev->mtu);
 547
 548         /* autodetect the encapsulation for each host. */
 549         memset(lp->default_proto, 0, sizeof(lp->default_proto));
 550
 551         /* the broadcast address is special - use the 'bcast' protocol */
 552         for (count = 0; count < 256; count++) {
 553                 if (arc_proto_map[count] == arc_bcast_proto) {
 554                         lp->default_proto[0] = count;
 555                         break;
 556                 }
 557         }
 558
 559         /* initialize buffers */
 560         atomic_set(&lp->buf_lock, 1);
 561
 562         lp->next_buf = lp->first_free_buf = 0;
 563         release_arcbuf(dev, 0);
 564         release_arcbuf(dev, 1);
 565         release_arcbuf(dev, 2);
 566         release_arcbuf(dev, 3);
 567         lp->cur_tx = lp->next_tx = -1;
 568         lp->cur_rx = -1;
 569
 570         lp->rfc1201.sequence = 1;
 571
 572         /* bring up the hardware driver */
 573         if (lp->hw.open)
 574                 lp->hw.open(dev);
 575
 576         if (dev->dev_addr[0] == 0)
 577                 arc_printk(D_NORMAL, dev, "WARNING!  Station address 00 is reserved for broadcasts!\n");
 578         else if (dev->dev_addr[0] == 255)
 579                 arc_printk(D_NORMAL, dev, "WARNING!  Station address FF may confuse DOS networking programs!\n");
 580
 581         arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
 582         if (lp->hw.status(dev) & RESETflag) {
 583                 arc_printk(D_DEBUG, dev, "%s: %d: %s\n",
 584                            __FILE__, __LINE__, __func__);
 585                 lp->hw.command(dev, CFLAGScmd | RESETclear);
 586         }
 587
 588         arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
 589         /* make sure we're ready to receive IRQ's. */
 590         lp->hw.intmask(dev, 0);
 591         udelay(1);              /* give it time to set the mask before
 592                                  * we reset it again. (may not even be
 593                                  * necessary)
 594                                  */
 595         arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
 596         lp->intmask = NORXflag | RECONflag;
 597         lp->hw.intmask(dev, lp->intmask);
 598         arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
 599
 600         netif_carrier_off(dev);
 601         netif_start_queue(dev);
 602         mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));
 603
 604         arcnet_led_event(dev, ARCNET_LED_EVENT_OPEN);
 605         return 0;
 606
 607  out_module_put:
 608         module_put(lp->hw.owner);
 609         return error;
 610 }
 611 EXPORT_SYMBOL(arcnet_open);
 612
 613 /* The inverse routine to arcnet_open - shuts down the card. */
 614 int arcnet_close(struct net_device *dev)
 615 {
 616         struct arcnet_local *lp = netdev_priv(dev);
 617
 618         arcnet_led_event(dev, ARCNET_LED_EVENT_STOP);
 619         del_timer_sync(&lp->timer);
 620
 621         netif_stop_queue(dev);
 622         netif_carrier_off(dev);
 623
 624         cancel_work_sync(&lp->reply_work);
 625
 626         /* flush TX and disable RX */
 627         lp->hw.intmask(dev, 0);
 628         lp->hw.command(dev, NOTXcmd);   /* stop transmit */
 629         lp->hw.command(dev, NORXcmd);   /* disable receive */
 630         mdelay(1);
 631
 632         /* shut down the card */
 633         lp->hw.close(dev);
 634
 635         /* reset counters */
 636         lp->reset_in_progress = 0;
 637
 638         module_put(lp->hw.owner);
 639         return 0;
 640 }
 641 EXPORT_SYMBOL(arcnet_close);
 642
 643 static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
 644                          unsigned short type, const void *daddr,
 645                          const void *saddr, unsigned len)
 646 {
 647         const struct arcnet_local *lp = netdev_priv(dev);
 648         uint8_t _daddr, proto_num;
 649         struct ArcProto *proto;
 650
 651         arc_printk(D_DURING, dev,
 652                    "create header from %d to %d; protocol %d (%Xh); size %u.\n",
 653                    saddr ? *(uint8_t *)saddr : -1,
 654                    daddr ? *(uint8_t *)daddr : -1,
 655                    type, type, len);
 656
 657         if (skb->len != 0 && len != skb->len)
 658                 arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  skb->len(%d) != len(%d)!\n",
 659                            skb->len, len);
 660
 661         /* Type is host order - ? */
 662         if (type == ETH_P_ARCNET) {
 663                 proto = arc_raw_proto;
 664                 arc_printk(D_DEBUG, dev, "arc_raw_proto used. proto='%c'\n",
 665                            proto->suffix);
 666                 _daddr = daddr ? *(uint8_t *)daddr : 0;
 667         } else if (!daddr) {
 668                 /* if the dest addr isn't provided, we can't choose an
 669                  * encapsulation!  Store the packet type (eg. ETH_P_IP)
 670                  * for now, and we'll push on a real header when we do
 671                  * rebuild_header.
 672                  */
 673                 *(uint16_t *)skb_push(skb, 2) = type;
 674                 /* XXX: Why not use skb->mac_len? */
 675                 if (skb->network_header - skb->mac_header != 2)
 676                         arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  diff (%u) is not 2!\n",
 677                                    skb->network_header - skb->mac_header);
 678                 return -2;      /* return error -- can't transmit yet! */
 679         } else {
 680                 /* otherwise, we can just add the header as usual. */
 681                 _daddr = *(uint8_t *)daddr;
 682                 proto_num = lp->default_proto[_daddr];
 683                 proto = arc_proto_map[proto_num];
 684                 arc_printk(D_DURING, dev, "building header for %02Xh using protocol '%c'\n",
 685                            proto_num, proto->suffix);
 686                 if (proto == &arc_proto_null && arc_bcast_proto != proto) {
 687                         arc_printk(D_DURING, dev, "actually, let's use '%c' instead.\n",
 688                                    arc_bcast_proto->suffix);
 689                         proto = arc_bcast_proto;
 690                 }
 691         }
 692         return proto->build_header(skb, dev, type, _daddr);
 693 }
 694
 695 /* Called by the kernel in order to transmit a packet. */
 696 netdev_tx_t arcnet_send_packet(struct sk_buff *skb,
 697                                struct net_device *dev)
 698 {
 699         struct arcnet_local *lp = netdev_priv(dev);
 700         struct archdr *pkt;
 701         struct arc_rfc1201 *soft;
 702         struct ArcProto *proto;
 703         int txbuf;
 704         unsigned long flags;
 705         int retval;
 706
 707         arc_printk(D_DURING, dev,
 708                    "transmit requested (status=%Xh, txbufs=%d/%d, len=%d, protocol %x)\n",
 709                    lp->hw.status(dev), lp->cur_tx, lp->next_tx, skb->len, skb->protocol);
 710
 711         pkt = (struct archdr *)skb->data;
 712         soft = &pkt->soft.rfc1201;
 713         proto = arc_proto_map[soft->proto];
 714
 715         arc_printk(D_SKB_SIZE, dev, "skb: transmitting %d bytes to %02X\n",
 716                    skb->len, pkt->hard.dest);
 717         if (BUGLVL(D_SKB))
 718                 arcnet_dump_skb(dev, skb, "tx");
 719
 720         /* fits in one packet? */
 721         if (skb->len - ARC_HDR_SIZE > XMTU && !proto->continue_tx) {
 722                 arc_printk(D_NORMAL, dev, "fixme: packet too large: compensating badly!\n");
 723                 dev_kfree_skb(skb);
 724                 return NETDEV_TX_OK;    /* don't try again */
 725         }
 726
 727         /* We're busy transmitting a packet... */
 728         netif_stop_queue(dev);
 729
 730         spin_lock_irqsave(&lp->lock, flags);
 731         lp->hw.intmask(dev, 0);
 732         if (lp->next_tx == -1)
 733                 txbuf = get_arcbuf(dev);
 734         else
 735                 txbuf = -1;
 736
 737         if (txbuf != -1) {
 738                 lp->outgoing.skb = skb;
 739                 if (proto->prepare_tx(dev, pkt, skb->len, txbuf) &&
 740                     !proto->ack_tx) {
 741                         /* done right away and we don't want to acknowledge
 742                          *  the package later - forget about it now
 743                          */
 744                         dev->stats.tx_bytes += skb->len;
 745                 } else {
 746                         /* do it the 'split' way */
 747                         lp->outgoing.proto = proto;
 748                         lp->outgoing.skb = skb;
 749                         lp->outgoing.pkt = pkt;
 750
 751                         if (proto->continue_tx &&
 752                             proto->continue_tx(dev, txbuf)) {
 753                                 arc_printk(D_NORMAL, dev,
 754                                            "bug! continue_tx finished the first time! (proto='%c')\n",
 755                                            proto->suffix);
 756                         }
 757                 }
 758                 retval = NETDEV_TX_OK;
 759                 lp->next_tx = txbuf;
 760         } else {
 761                 retval = NETDEV_TX_BUSY;
 762         }
 763
 764         arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x\n",
 765                    __FILE__, __LINE__, __func__, lp->hw.status(dev));
 766         /* make sure we didn't ignore a TX IRQ while we were in here */
 767         lp->hw.intmask(dev, 0);
 768
 769         arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
 770         lp->intmask |= TXFREEflag | EXCNAKflag;
 771         lp->hw.intmask(dev, lp->intmask);
 772         arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x\n",
 773                    __FILE__, __LINE__, __func__, lp->hw.status(dev));
 774
 775         arcnet_led_event(dev, ARCNET_LED_EVENT_TX);
 776
 777         spin_unlock_irqrestore(&lp->lock, flags);
 778         return retval;          /* no need to try again */
 779 }
 780 EXPORT_SYMBOL(arcnet_send_packet);
 781
 782 /* Actually start transmitting a packet that was loaded into a buffer
 783  * by prepare_tx.  This should _only_ be called by the interrupt handler.
 784  */
 785 static int go_tx(struct net_device *dev)
 786 {
 787         struct arcnet_local *lp = netdev_priv(dev);
 788
 789         arc_printk(D_DURING, dev, "go_tx: status=%Xh, intmask=%Xh, next_tx=%d, cur_tx=%d\n",
 790                    lp->hw.status(dev), lp->intmask, lp->next_tx, lp->cur_tx);
 791
 792         if (lp->cur_tx != -1 || lp->next_tx == -1)
 793                 return 0;
 794
 795         if (BUGLVL(D_TX))
 796                 arcnet_dump_packet(dev, lp->next_tx, "go_tx", 0);
 797
 798         lp->cur_tx = lp->next_tx;
 799         lp->next_tx = -1;
 800
 801         /* start sending */
 802         lp->hw.command(dev, TXcmd | (lp->cur_tx << 3));
 803
 804         dev->stats.tx_packets++;
 805         lp->lasttrans_dest = lp->lastload_dest;
 806         lp->lastload_dest = 0;
 807         lp->excnak_pending = 0;
 808         lp->intmask |= TXFREEflag | EXCNAKflag;
 809
 810         return 1;
 811 }
 812
 813 /* Called by the kernel when transmit times out */
 814 void arcnet_timeout(struct net_device *dev, unsigned int txqueue)
 815 {
 816         unsigned long flags;
 817         struct arcnet_local *lp = netdev_priv(dev);
 818         int status = lp->hw.status(dev);
 819         char *msg;
 820
 821         spin_lock_irqsave(&lp->lock, flags);
 822         if (status & TXFREEflag) {      /* transmit _DID_ finish */
 823                 msg = " - missed IRQ?";
 824         } else {
 825                 msg = "";
 826                 dev->stats.tx_aborted_errors++;
 827                 lp->timed_out = 1;
 828                 lp->hw.command(dev, NOTXcmd | (lp->cur_tx << 3));
 829         }
 830         dev->stats.tx_errors++;
 831
 832         /* make sure we didn't miss a TX or a EXC NAK IRQ */
 833         lp->hw.intmask(dev, 0);
 834         lp->intmask |= TXFREEflag | EXCNAKflag;
 835         lp->hw.intmask(dev, lp->intmask);
 836
 837         spin_unlock_irqrestore(&lp->lock, flags);
 838
 839         if (time_after(jiffies, lp->last_timeout + 10 * HZ)) {
 840                 arc_printk(D_EXTRA, dev, "tx timed out%s (status=%Xh, intmask=%Xh, dest=%02Xh)\n",
 841                            msg, status, lp->intmask, lp->lasttrans_dest);
 842                 lp->last_timeout = jiffies;
 843         }
 844
 845         if (lp->cur_tx == -1)
 846                 netif_wake_queue(dev);
 847 }
 848 EXPORT_SYMBOL(arcnet_timeout);
 849
 850 /* The typical workload of the driver: Handle the network interface
 851  * interrupts. Establish which device needs attention, and call the correct
 852  * chipset interrupt handler.
 853  */
 854 irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 855 {
 856         struct net_device *dev = dev_id;
 857         struct arcnet_local *lp;
 858         int recbuf, status, diagstatus, didsomething, boguscount;
 859         unsigned long flags;
 860         int retval = IRQ_NONE;
 861
 862         arc_printk(D_DURING, dev, "\n");
 863
 864         arc_printk(D_DURING, dev, "in arcnet_interrupt\n");
 865
 866         lp = netdev_priv(dev);
 867         BUG_ON(!lp);
 868
 869         spin_lock_irqsave(&lp->lock, flags);
 870
 871         if (lp->reset_in_progress)
 872                 goto out;
 873
 874         /* RESET flag was enabled - if device is not running, we must
 875          * clear it right away (but nothing else).
 876          */
 877         if (!netif_running(dev)) {
 878                 if (lp->hw.status(dev) & RESETflag)
 879                         lp->hw.command(dev, CFLAGScmd | RESETclear);
 880                 lp->hw.intmask(dev, 0);
 881                 spin_unlock_irqrestore(&lp->lock, flags);
 882                 return retval;
 883         }
 884
 885         arc_printk(D_DURING, dev, "in arcnet_inthandler (status=%Xh, intmask=%Xh)\n",
 886                    lp->hw.status(dev), lp->intmask);
 887
 888         boguscount = 5;
 889         do {
 890                 status = lp->hw.status(dev);
 891                 diagstatus = (status >> 8) & 0xFF;
 892
 893                 arc_printk(D_DEBUG, dev, "%s: %d: %s: status=%x\n",
 894                            __FILE__, __LINE__, __func__, status);
 895                 didsomething = 0;
 896
 897                 /* RESET flag was enabled - card is resetting and if RX is
 898                  * disabled, it's NOT because we just got a packet.
 899                  *
 900                  * The card is in an undefined state.
 901                  * Clear it out and start over.
 902                  */
 903                 if (status & RESETflag) {
 904                         arc_printk(D_NORMAL, dev, "spurious reset (status=%Xh)\n",
 905                                    status);
 906
 907                         lp->reset_in_progress = 1;
 908                         netif_stop_queue(dev);
 909                         netif_carrier_off(dev);
 910                         schedule_work(&lp->reset_work);
 911
 912                         /* get out of the interrupt handler! */
 913                         goto out;
 914                 }
 915                 /* RX is inhibited - we must have received something.
 916                  * Prepare to receive into the next buffer.
 917                  *
 918                  * We don't actually copy the received packet from the card
 919                  * until after the transmit handler runs (and possibly
 920                  * launches the next tx); this should improve latency slightly
 921                  * if we get both types of interrupts at once.
 922                  */
 923                 recbuf = -1;
 924                 if (status & lp->intmask & NORXflag) {
 925                         recbuf = lp->cur_rx;
 926                         arc_printk(D_DURING, dev, "Buffer #%d: receive irq (status=%Xh)\n",
 927                                    recbuf, status);
 928
 929                         lp->cur_rx = get_arcbuf(dev);
 930                         if (lp->cur_rx != -1) {
 931                                 arc_printk(D_DURING, dev, "enabling receive to buffer #%d\n",
 932                                            lp->cur_rx);
 933                                 lp->hw.command(dev, RXcmd | (lp->cur_rx << 3) | RXbcasts);
 934                         }
 935                         didsomething++;
 936                 }
 937
 938                 if ((diagstatus & EXCNAKflag)) {
 939                         arc_printk(D_DURING, dev, "EXCNAK IRQ (diagstat=%Xh)\n",
 940                                    diagstatus);
 941
 942                         lp->hw.command(dev, NOTXcmd);      /* disable transmit */
 943                         lp->excnak_pending = 1;
 944
 945                         lp->hw.command(dev, EXCNAKclear);
 946                         lp->intmask &= ~(EXCNAKflag);
 947                         didsomething++;
 948                 }
 949
 950                 /* a transmit finished, and we're interested in it. */
 951                 if ((status & lp->intmask & TXFREEflag) || lp->timed_out) {
 952                         int ackstatus;
 953                         lp->intmask &= ~(TXFREEflag | EXCNAKflag);
 954
 955                         if (status & TXACKflag)
 956                                 ackstatus = 2;
 957                         else if (lp->excnak_pending)
 958                                 ackstatus = 1;
 959                         else
 960                                 ackstatus = 0;
 961
 962                         arc_printk(D_DURING, dev, "TX IRQ (stat=%Xh)\n",
 963                                    status);
 964
 965                         if (lp->cur_tx != -1 && !lp->timed_out) {
 966                                 if (!(status & TXACKflag)) {
 967                                         if (lp->lasttrans_dest != 0) {
 968                                                 arc_printk(D_EXTRA, dev,
 969                                                            "transmit was not acknowledged! (status=%Xh, dest=%02Xh)\n",
 970                                                            status,
 971                                                            lp->lasttrans_dest);
 972                                                 dev->stats.tx_errors++;
 973                                                 dev->stats.tx_carrier_errors++;
 974                                         } else {
 975                                                 arc_printk(D_DURING, dev,
 976                                                            "broadcast was not acknowledged; that's normal (status=%Xh, dest=%02Xh)\n",
 977                                                            status,
 978                                                            lp->lasttrans_dest);
 979                                         }
 980                                 }
 981
 982                                 if (lp->outgoing.proto &&
 983                                     lp->outgoing.proto->ack_tx) {
 984                                         lp->outgoing.proto
 985                                                 ->ack_tx(dev, ackstatus);
 986                                 }
 987                                 lp->reply_status = ackstatus;
 988                                 queue_work(system_bh_highpri_wq, &lp->reply_work);
 989                         }
 990                         if (lp->cur_tx != -1)
 991                                 release_arcbuf(dev, lp->cur_tx);
 992
 993                         lp->cur_tx = -1;
 994                         lp->timed_out = 0;
 995                         didsomething++;
 996
 997                         /* send another packet if there is one */
 998                         go_tx(dev);
 999
1000                         /* continue a split packet, if any */
1001                         if (lp->outgoing.proto &&
1002                             lp->outgoing.proto->continue_tx) {
1003                                 int txbuf = get_arcbuf(dev);
1004
1005                                 if (txbuf != -1) {
1006                                         if (lp->outgoing.proto->continue_tx(dev, txbuf)) {
1007                                                 /* that was the last segment */
1008                                                 dev->stats.tx_bytes += lp->outgoing.skb->len;
1009                                                 if (!lp->outgoing.proto->ack_tx) {
1010                                                         dev_kfree_skb_irq(lp->outgoing.skb);
1011                                                         lp->outgoing.proto = NULL;
1012                                                 }
1013                                         }
1014                                         lp->next_tx = txbuf;
1015                                 }
1016                         }
1017                         /* inform upper layers of idleness, if necessary */
1018                         if (lp->cur_tx == -1)
1019                                 netif_wake_queue(dev);
1020                 }
1021                 /* now process the received packet, if any */
1022                 if (recbuf != -1) {
1023                         if (BUGLVL(D_RX))
1024                                 arcnet_dump_packet(dev, recbuf, "rx irq", 0);
1025
1026                         arcnet_rx(dev, recbuf);
1027                         release_arcbuf(dev, recbuf);
1028
1029                         didsomething++;
1030                 }
1031                 if (status & lp->intmask & RECONflag) {
1032                         lp->hw.command(dev, CFLAGScmd | CONFIGclear);
1033                         dev->stats.tx_carrier_errors++;
1034
1035                         arc_printk(D_RECON, dev, "Network reconfiguration detected (status=%Xh)\n",
1036                                    status);
1037                         if (netif_carrier_ok(dev)) {
1038                                 netif_carrier_off(dev);
1039                                 netdev_info(dev, "link down\n");
1040                         }
1041                         mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));
1042
1043                         arcnet_led_event(dev, ARCNET_LED_EVENT_RECON);
1044                         /* MYRECON bit is at bit 7 of diagstatus */
1045                         if (diagstatus & 0x80)
1046                                 arc_printk(D_RECON, dev, "Put out that recon myself\n");
1047
1048                         /* is the RECON info empty or old? */
1049                         if (!lp->first_recon || !lp->last_recon ||
1050                             time_after(jiffies, lp->last_recon + HZ * 10)) {
1051                                 if (lp->network_down)
1052                                         arc_printk(D_NORMAL, dev, "reconfiguration detected: cabling restored?\n");
1053                                 lp->first_recon = lp->last_recon = jiffies;
1054                                 lp->num_recons = lp->network_down = 0;
1055
1056                                 arc_printk(D_DURING, dev, "recon: clearing counters.\n");
1057                         } else {        /* add to current RECON counter */
1058                                 lp->last_recon = jiffies;
1059                                 lp->num_recons++;
1060
1061                                 arc_printk(D_DURING, dev, "recon: counter=%d, time=%lds, net=%d\n",
1062                                            lp->num_recons,
1063                                            (lp->last_recon - lp->first_recon) / HZ,
1064                                            lp->network_down);
1065
1066                                 /* if network is marked up;
1067                                  * and first_recon and last_recon are 60+ apart;
1068                                  * and the average no. of recons counted is
1069                                  *    > RECON_THRESHOLD/min;
1070                                  * then print a warning message.
1071                                  */
1072                                 if (!lp->network_down &&
1073                                     (lp->last_recon - lp->first_recon) <= HZ * 60 &&
1074                                     lp->num_recons >= RECON_THRESHOLD) {
1075                                         lp->network_down = 1;
1076                                         arc_printk(D_NORMAL, dev, "many reconfigurations detected: cabling problem?\n");
1077                                 } else if (!lp->network_down &&
1078                                            lp->last_recon - lp->first_recon > HZ * 60) {
1079                                         /* reset counters if we've gone for
1080                                          *  over a minute.
1081                                          */
1082                                         lp->first_recon = lp->last_recon;
1083                                         lp->num_recons = 1;
1084                                 }
1085                         }
1086                 } else if (lp->network_down &&
1087                            time_after(jiffies, lp->last_recon + HZ * 10)) {
1088                         if (lp->network_down)
1089                                 arc_printk(D_NORMAL, dev, "cabling restored?\n");
1090                         lp->first_recon = lp->last_recon = 0;
1091                         lp->num_recons = lp->network_down = 0;
1092
1093                         arc_printk(D_DURING, dev, "not recon: clearing counters anyway.\n");
1094                         netif_carrier_on(dev);
1095                 }
1096
1097                 if (didsomething)
1098                         retval |= IRQ_HANDLED;
1099         } while (--boguscount && didsomething);
1100
1101         arc_printk(D_DURING, dev, "arcnet_interrupt complete (status=%Xh, count=%d)\n",
1102                    lp->hw.status(dev), boguscount);
1103         arc_printk(D_DURING, dev, "\n");
1104
1105         lp->hw.intmask(dev, 0);
1106         udelay(1);
1107         lp->hw.intmask(dev, lp->intmask);
1108
1109 out:
1110         spin_unlock_irqrestore(&lp->lock, flags);
1111         return retval;
1112 }
1113 EXPORT_SYMBOL(arcnet_interrupt);
1114
1115 /* This is a generic packet receiver that calls arcnet??_rx depending on the
1116  * protocol ID found.
1117  */
1118 static void arcnet_rx(struct net_device *dev, int bufnum)
1119 {
1120         struct arcnet_local *lp = netdev_priv(dev);
1121         union {
1122                 struct archdr pkt;
1123                 char buf[512];
1124         } rxdata;
1125         struct arc_rfc1201 *soft;
1126         int length, ofs;
1127
1128         soft = &rxdata.pkt.soft.rfc1201;
1129
1130         lp->hw.copy_from_card(dev, bufnum, 0, &rxdata.pkt, ARC_HDR_SIZE);
1131         if (rxdata.pkt.hard.offset[0]) {
1132                 ofs = rxdata.pkt.hard.offset[0];
1133                 length = 256 - ofs;
1134         } else {
1135                 ofs = rxdata.pkt.hard.offset[1];
1136                 length = 512 - ofs;
1137         }
1138
1139         /* get the full header, if possible */
1140         if (sizeof(rxdata.pkt.soft) <= length) {
1141                 lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(rxdata.pkt.soft));
1142         } else {
1143                 memset(&rxdata.pkt.soft, 0, sizeof(rxdata.pkt.soft));
1144                 lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
1145         }
1146
1147         arc_printk(D_DURING, dev, "Buffer #%d: received packet from %02Xh to %02Xh (%d+4 bytes)\n",
1148                    bufnum, rxdata.pkt.hard.source, rxdata.pkt.hard.dest, length);
1149
1150         dev->stats.rx_packets++;
1151         dev->stats.rx_bytes += length + ARC_HDR_SIZE;
1152
1153         /* call the right receiver for the protocol */
1154         if (arc_proto_map[soft->proto]->is_ip) {
1155                 if (BUGLVL(D_PROTO)) {
1156                         struct ArcProto
1157                         *oldp = arc_proto_map[lp->default_proto[rxdata.pkt.hard.source]],
1158                         *newp = arc_proto_map[soft->proto];
1159
1160                         if (oldp != newp) {
1161                                 arc_printk(D_PROTO, dev,
1162                                            "got protocol %02Xh; encap for host %02Xh is now '%c' (was '%c')\n",
1163                                            soft->proto, rxdata.pkt.hard.source,
1164                                            newp->suffix, oldp->suffix);
1165                         }
1166                 }
1167
1168                 /* broadcasts will always be done with the last-used encap. */
1169                 lp->default_proto[0] = soft->proto;
1170
1171                 /* in striking contrast, the following isn't a hack. */
1172                 lp->default_proto[rxdata.pkt.hard.source] = soft->proto;
1173         }
1174         /* call the protocol-specific receiver. */
1175         arc_proto_map[soft->proto]->rx(dev, bufnum, &rxdata.pkt, length);
1176 }
1177
1178 static void null_rx(struct net_device *dev, int bufnum,
1179                     struct archdr *pkthdr, int length)
1180 {
1181         arc_printk(D_PROTO, dev,
1182                    "rx: don't know how to deal with proto %02Xh from host %02Xh.\n",
1183                    pkthdr->soft.rfc1201.proto, pkthdr->hard.source);
1184 }
1185
1186 static int null_build_header(struct sk_buff *skb, struct net_device *dev,
1187                              unsigned short type, uint8_t daddr)
1188 {
1189         struct arcnet_local *lp = netdev_priv(dev);
1190
1191         arc_printk(D_PROTO, dev,
1192                    "tx: can't build header for encap %02Xh; load a protocol driver.\n",
1193                    lp->default_proto[daddr]);
1194
1195         /* always fails */
1196         return 0;
1197 }
1198
1199 /* the "do nothing" prepare_tx function warns that there's nothing to do. */
1200 static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
1201                            int length, int bufnum)
1202 {
1203         struct arcnet_local *lp = netdev_priv(dev);
1204         struct arc_hardware newpkt;
1205
1206         arc_printk(D_PROTO, dev, "tx: no encap for this host; load a protocol driver.\n");
1207
1208         /* send a packet to myself -- will never get received, of course */
1209         newpkt.source = newpkt.dest = dev->dev_addr[0];
1210
1211         /* only one byte of actual data (and it's random) */
1212         newpkt.offset[0] = 0xFF;
1213
1214         lp->hw.copy_to_card(dev, bufnum, 0, &newpkt, ARC_HDR_SIZE);
1215
1216         return 1;               /* done */
1217 }