1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* $Id: plip.c,v 1.3.6.2 1997/04/16 15:07:56 phil Exp $ */ 3 /* PLIP: A parallel port "network" driver for Linux. */ 4 /* This driver is for parallel port with 5-bit cable (LapLink (R) cable). */ 5 /* 6 * Authors: Donald Becker <becker@scyld.com> 7 * Tommy Thorn <thorn@daimi.aau.dk> 8 * Tanabe Hiroyasu <hiro@sanpo.t.u-tokyo.ac.jp> 9 * Alan Cox <gw4pts@gw4pts.ampr.org> 10 * Peter Bauer <100136.3530@compuserve.com> 11 * Niibe Yutaka <gniibe@mri.co.jp> 12 * Nimrod Zimerman <zimerman@mailandnews.com> 13 * 14 * Enhancements: 15 * Modularization and ifreq/ifmap support by Alan Cox. 16 * Rewritten by Niibe Yutaka. 17 * parport-sharing awareness code by Philip Blundell. 18 * SMP locking by Niibe Yutaka. 19 * Support for parallel ports with no IRQ (poll mode), 20 * Modifications to use the parallel port API 21 * by Nimrod Zimerman. 22 * 23 * Fixes: 24 * Niibe Yutaka 25 * - Module initialization. 26 * - MTU fix. 27 * - Make sure other end is OK, before sending a packet. 28 * - Fix immediate timer problem. 29 * 30 * Al Viro 31 * - Changed {enable,disable}_irq handling to make it work 32 * with new ("stack") semantics. 33 */ 34 35 /* 36 * Original version and the name 'PLIP' from Donald Becker <becker@scyld.com> 37 * inspired by Russ Nelson's parallel port packet driver. 38 * 39 * NOTE: 40 * Tanabe Hiroyasu had changed the protocol, and it was in Linux v1.0. 41 * Because of the necessity to communicate to DOS machines with the 42 * Crynwr packet driver, Peter Bauer changed the protocol again 43 * back to original protocol. 44 * 45 * This version follows original PLIP protocol. 46 * So, this PLIP can't communicate the PLIP of Linux v1.0. 47 */ 48 49 /* 50 * To use with DOS box, please do (Turn on ARP switch): 51 * # ifconfig plip[0-2] arp 52 */ 53 static const char version[] = "NET3 PLIP version 2.4-parport gniibe@mri.co.jp\n"; 54 55 /* 56 Sources: 57 Ideas and protocols came from Russ Nelson's <nelson@crynwr.com> 58 "parallel.asm" parallel port packet driver. 59 60 The "Crynwr" parallel port standard specifies the following protocol: 61 Trigger by sending nibble '0x8' (this causes interrupt on other end) 62 count-low octet 63 count-high octet 64 ... data octets 65 checksum octet 66 Each octet is sent as <wait for rx. '0x1?'> <send 0x10+(octet&0x0F)> 67 <wait for rx. '0x0?'> <send 0x00+((octet>>4)&0x0F)> 68 69 The packet is encapsulated as if it were ethernet. 70 71 The cable used is a de facto standard parallel null cable -- sold as 72 a "LapLink" cable by various places. You'll need a 12-conductor cable to 73 make one yourself. The wiring is: 74 SLCTIN 17 - 17 75 GROUND 25 - 25 76 D0->ERROR 2 - 15 15 - 2 77 D1->SLCT 3 - 13 13 - 3 78 D2->PAPOUT 4 - 12 12 - 4 79 D3->ACK 5 - 10 10 - 5 80 D4->BUSY 6 - 11 11 - 6 81 Do not connect the other pins. They are 82 D5,D6,D7 are 7,8,9 83 STROBE is 1, FEED is 14, INIT is 16 84 extra grounds are 18,19,20,21,22,23,24 85 */ 86 87 #include <linux/module.h> 88 #include <linux/kernel.h> 89 #include <linux/types.h> 90 #include <linux/fcntl.h> 91 #include <linux/interrupt.h> 92 #include <linux/string.h> 93 #include <linux/slab.h> 94 #include <linux/if_ether.h> 95 #include <linux/in.h> 96 #include <linux/errno.h> 97 #include <linux/delay.h> 98 #include <linux/init.h> 99 #include <linux/netdevice.h> 100 #include <linux/etherdevice.h> 101 #include <linux/inetdevice.h> 102 #include <linux/skbuff.h> 103 #include <linux/if_plip.h> 104 #include <linux/workqueue.h> 105 #include <linux/spinlock.h> 106 #include <linux/completion.h> 107 #include <linux/parport.h> 108 #include <linux/bitops.h> 109 110 #include <net/neighbour.h> 111 112 #include <asm/irq.h> 113 #include <asm/byteorder.h> 114 115 /* Maximum number of devices to support. */ 116 #define PLIP_MAX 8 117 118 /* Use 0 for production, 1 for verification, >2 for debug */ 119 #ifndef NET_DEBUG 120 #define NET_DEBUG 1 121 #endif 122 static const unsigned int net_debug = NET_DEBUG; 123 124 #define ENABLE(irq) if (irq != -1) enable_irq(irq) 125 #define DISABLE(irq) if (irq != -1) disable_irq(irq) 126 127 /* In micro second */ 128 #define PLIP_DELAY_UNIT 1 129 130 /* Connection time out = PLIP_TRIGGER_WAIT * PLIP_DELAY_UNIT usec */ 131 #define PLIP_TRIGGER_WAIT 500 132 133 /* Nibble time out = PLIP_NIBBLE_WAIT * PLIP_DELAY_UNIT usec */ 134 #define PLIP_NIBBLE_WAIT 3000 135 136 /* Bottom halves */ 137 static void plip_kick_bh(struct work_struct *work); 138 static void plip_bh(struct work_struct *work); 139 static void plip_timer_bh(struct work_struct *work); 140 141 /* Interrupt handler */ 142 static void plip_interrupt(void *dev_id); 143 144 /* Functions for DEV methods */ 145 static int plip_tx_packet(struct sk_buff *skb, struct net_device *dev); 146 static int plip_hard_header(struct sk_buff *skb, struct net_device *dev, 147 unsigned short type, const void *daddr, 148 const void *saddr, unsigned len); 149 static int plip_hard_header_cache(const struct neighbour *neigh, 150 struct hh_cache *hh, __be16 type); 151 static int plip_open(struct net_device *dev); 152 static int plip_close(struct net_device *dev); 153 static int plip_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd); 154 static int plip_preempt(void *handle); 155 static void plip_wakeup(void *handle); 156 157 enum plip_connection_state { 158 PLIP_CN_NONE=0, 159 PLIP_CN_RECEIVE, 160 PLIP_CN_SEND, 161 PLIP_CN_CLOSING, 162 PLIP_CN_ERROR 163 }; 164 165 enum plip_packet_state { 166 PLIP_PK_DONE=0, 167 PLIP_PK_TRIGGER, 168 PLIP_PK_LENGTH_LSB, 169 PLIP_PK_LENGTH_MSB, 170 PLIP_PK_DATA, 171 PLIP_PK_CHECKSUM 172 }; 173 174 enum plip_nibble_state { 175 PLIP_NB_BEGIN, 176 PLIP_NB_1, 177 PLIP_NB_2, 178 }; 179 180 struct plip_local { 181 enum plip_packet_state state; 182 enum plip_nibble_state nibble; 183 union { 184 struct { 185 #if defined(__LITTLE_ENDIAN) 186 unsigned char lsb; 187 unsigned char msb; 188 #elif defined(__BIG_ENDIAN) 189 unsigned char msb; 190 unsigned char lsb; 191 #else 192 #error "Please fix the endianness defines in <asm/byteorder.h>" 193 #endif 194 } b; 195 unsigned short h; 196 } length; 197 unsigned short byte; 198 unsigned char checksum; 199 unsigned char data; 200 struct sk_buff *skb; 201 }; 202 203 struct net_local { 204 struct net_device *dev; 205 struct work_struct immediate; 206 struct delayed_work deferred; 207 struct delayed_work timer; 208 struct plip_local snd_data; 209 struct plip_local rcv_data; 210 struct pardevice *pardev; 211 unsigned long trigger; 212 unsigned long nibble; 213 enum plip_connection_state connection; 214 unsigned short timeout_count; 215 int is_deferred; 216 int port_owner; 217 int should_relinquish; 218 spinlock_t lock; 219 atomic_t kill_timer; 220 struct completion killed_timer_cmp; 221 }; 222 223 static inline void enable_parport_interrupts (struct net_device *dev) 224 { 225 if (dev->irq != -1) 226 { 227 struct parport *port = 228 ((struct net_local *)netdev_priv(dev))->pardev->port; 229 port->ops->enable_irq (port); 230 } 231 } 232 233 static inline void disable_parport_interrupts (struct net_device *dev) 234 { 235 if (dev->irq != -1) 236 { 237 struct parport *port = 238 ((struct net_local *)netdev_priv(dev))->pardev->port; 239 port->ops->disable_irq (port); 240 } 241 } 242 243 static inline void write_data (struct net_device *dev, unsigned char data) 244 { 245 struct parport *port = 246 ((struct net_local *)netdev_priv(dev))->pardev->port; 247 248 port->ops->write_data (port, data); 249 } 250 251 static inline unsigned char read_status (struct net_device *dev) 252 { 253 struct parport *port = 254 ((struct net_local *)netdev_priv(dev))->pardev->port; 255 256 return port->ops->read_status (port); 257 } 258 259 static const struct header_ops plip_header_ops = { 260 .create = plip_hard_header, 261 .cache = plip_hard_header_cache, 262 }; 263 264 static const struct net_device_ops plip_netdev_ops = { 265 .ndo_open = plip_open, 266 .ndo_stop = plip_close, 267 .ndo_start_xmit = plip_tx_packet, 268 .ndo_do_ioctl = plip_ioctl, 269 .ndo_set_mac_address = eth_mac_addr, 270 .ndo_validate_addr = eth_validate_addr, 271 }; 272 273 /* Entry point of PLIP driver. 274 Probe the hardware, and register/initialize the driver. 275 276 PLIP is rather weird, because of the way it interacts with the parport 277 system. It is _not_ initialised from Space.c. Instead, plip_init() 278 is called, and that function makes up a "struct net_device" for each port, and 279 then calls us here. 280 281 */ 282 static void 283 plip_init_netdev(struct net_device *dev) 284 { 285 struct net_local *nl = netdev_priv(dev); 286 287 /* Then, override parts of it */ 288 dev->tx_queue_len = 10; 289 dev->flags = IFF_POINTOPOINT|IFF_NOARP; 290 memset(dev->dev_addr, 0xfc, ETH_ALEN); 291 292 dev->netdev_ops = &plip_netdev_ops; 293 dev->header_ops = &plip_header_ops; 294 295 296 nl->port_owner = 0; 297 298 /* Initialize constants */ 299 nl->trigger = PLIP_TRIGGER_WAIT; 300 nl->nibble = PLIP_NIBBLE_WAIT; 301 302 /* Initialize task queue structures */ 303 INIT_WORK(&nl->immediate, plip_bh); 304 INIT_DELAYED_WORK(&nl->deferred, plip_kick_bh); 305 306 if (dev->irq == -1) 307 INIT_DELAYED_WORK(&nl->timer, plip_timer_bh); 308 309 spin_lock_init(&nl->lock); 310 } 311 312 /* Bottom half handler for the delayed request. 313 This routine is kicked by do_timer(). 314 Request `plip_bh' to be invoked. */ 315 static void 316 plip_kick_bh(struct work_struct *work) 317 { 318 struct net_local *nl = 319 container_of(work, struct net_local, deferred.work); 320 321 if (nl->is_deferred) 322 schedule_work(&nl->immediate); 323 } 324 325 /* Forward declarations of internal routines */ 326 static int plip_none(struct net_device *, struct net_local *, 327 struct plip_local *, struct plip_local *); 328 static int plip_receive_packet(struct net_device *, struct net_local *, 329 struct plip_local *, struct plip_local *); 330 static int plip_send_packet(struct net_device *, struct net_local *, 331 struct plip_local *, struct plip_local *); 332 static int plip_connection_close(struct net_device *, struct net_local *, 333 struct plip_local *, struct plip_local *); 334 static int plip_error(struct net_device *, struct net_local *, 335 struct plip_local *, struct plip_local *); 336 static int plip_bh_timeout_error(struct net_device *dev, struct net_local *nl, 337 struct plip_local *snd, 338 struct plip_local *rcv, 339 int error); 340 341 #define OK 0 342 #define TIMEOUT 1 343 #define ERROR 2 344 #define HS_TIMEOUT 3 345 346 typedef int (*plip_func)(struct net_device *dev, struct net_local *nl, 347 struct plip_local *snd, struct plip_local *rcv); 348 349 static const plip_func connection_state_table[] = 350 { 351 plip_none, 352 plip_receive_packet, 353 plip_send_packet, 354 plip_connection_close, 355 plip_error 356 }; 357 358 /* Bottom half handler of PLIP. */ 359 static void 360 plip_bh(struct work_struct *work) 361 { 362 struct net_local *nl = container_of(work, struct net_local, immediate); 363 struct plip_local *snd = &nl->snd_data; 364 struct plip_local *rcv = &nl->rcv_data; 365 plip_func f; 366 int r; 367 368 nl->is_deferred = 0; 369 f = connection_state_table[nl->connection]; 370 if ((r = (*f)(nl->dev, nl, snd, rcv)) != OK && 371 (r = plip_bh_timeout_error(nl->dev, nl, snd, rcv, r)) != OK) { 372 nl->is_deferred = 1; 373 schedule_delayed_work(&nl->deferred, 1); 374 } 375 } 376 377 static void 378 plip_timer_bh(struct work_struct *work) 379 { 380 struct net_local *nl = 381 container_of(work, struct net_local, timer.work); 382 383 if (!(atomic_read (&nl->kill_timer))) { 384 plip_interrupt (nl->dev); 385 386 schedule_delayed_work(&nl->timer, 1); 387 } 388 else { 389 complete(&nl->killed_timer_cmp); 390 } 391 } 392 393 static int 394 plip_bh_timeout_error(struct net_device *dev, struct net_local *nl, 395 struct plip_local *snd, struct plip_local *rcv, 396 int error) 397 { 398 unsigned char c0; 399 /* 400 * This is tricky. If we got here from the beginning of send (either 401 * with ERROR or HS_TIMEOUT) we have IRQ enabled. Otherwise it's 402 * already disabled. With the old variant of {enable,disable}_irq() 403 * extra disable_irq() was a no-op. Now it became mortal - it's 404 * unbalanced and thus we'll never re-enable IRQ (until rmmod plip, 405 * that is). So we have to treat HS_TIMEOUT and ERROR from send 406 * in a special way. 407 */ 408 409 spin_lock_irq(&nl->lock); 410 if (nl->connection == PLIP_CN_SEND) { 411 412 if (error != ERROR) { /* Timeout */ 413 nl->timeout_count++; 414 if ((error == HS_TIMEOUT && nl->timeout_count <= 10) || 415 nl->timeout_count <= 3) { 416 spin_unlock_irq(&nl->lock); 417 /* Try again later */ 418 return TIMEOUT; 419 } 420 c0 = read_status(dev); 421 printk(KERN_WARNING "%s: transmit timeout(%d,%02x)\n", 422 dev->name, snd->state, c0); 423 } else 424 error = HS_TIMEOUT; 425 dev->stats.tx_errors++; 426 dev->stats.tx_aborted_errors++; 427 } else if (nl->connection == PLIP_CN_RECEIVE) { 428 if (rcv->state == PLIP_PK_TRIGGER) { 429 /* Transmission was interrupted. */ 430 spin_unlock_irq(&nl->lock); 431 return OK; 432 } 433 if (error != ERROR) { /* Timeout */ 434 if (++nl->timeout_count <= 3) { 435 spin_unlock_irq(&nl->lock); 436 /* Try again later */ 437 return TIMEOUT; 438 } 439 c0 = read_status(dev); 440 printk(KERN_WARNING "%s: receive timeout(%d,%02x)\n", 441 dev->name, rcv->state, c0); 442 } 443 dev->stats.rx_dropped++; 444 } 445 rcv->state = PLIP_PK_DONE; 446 if (rcv->skb) { 447 kfree_skb(rcv->skb); 448 rcv->skb = NULL; 449 } 450 snd->state = PLIP_PK_DONE; 451 if (snd->skb) { 452 dev_kfree_skb(snd->skb); 453 snd->skb = NULL; 454 } 455 spin_unlock_irq(&nl->lock); 456 if (error == HS_TIMEOUT) { 457 DISABLE(dev->irq); 458 synchronize_irq(dev->irq); 459 } 460 disable_parport_interrupts (dev); 461 netif_stop_queue (dev); 462 nl->connection = PLIP_CN_ERROR; 463 write_data (dev, 0x00); 464 465 return TIMEOUT; 466 } 467 468 static int 469 plip_none(struct net_device *dev, struct net_local *nl, 470 struct plip_local *snd, struct plip_local *rcv) 471 { 472 return OK; 473 } 474 475 /* PLIP_RECEIVE --- receive a byte(two nibbles) 476 Returns OK on success, TIMEOUT on timeout */ 477 static inline int 478 plip_receive(unsigned short nibble_timeout, struct net_device *dev, 479 enum plip_nibble_state *ns_p, unsigned char *data_p) 480 { 481 unsigned char c0, c1; 482 unsigned int cx; 483 484 switch (*ns_p) { 485 case PLIP_NB_BEGIN: 486 cx = nibble_timeout; 487 while (1) { 488 c0 = read_status(dev); 489 udelay(PLIP_DELAY_UNIT); 490 if ((c0 & 0x80) == 0) { 491 c1 = read_status(dev); 492 if (c0 == c1) 493 break; 494 } 495 if (--cx == 0) 496 return TIMEOUT; 497 } 498 *data_p = (c0 >> 3) & 0x0f; 499 write_data (dev, 0x10); /* send ACK */ 500 *ns_p = PLIP_NB_1; 501 /* fall through */ 502 503 case PLIP_NB_1: 504 cx = nibble_timeout; 505 while (1) { 506 c0 = read_status(dev); 507 udelay(PLIP_DELAY_UNIT); 508 if (c0 & 0x80) { 509 c1 = read_status(dev); 510 if (c0 == c1) 511 break; 512 } 513 if (--cx == 0) 514 return TIMEOUT; 515 } 516 *data_p |= (c0 << 1) & 0xf0; 517 write_data (dev, 0x00); /* send ACK */ 518 *ns_p = PLIP_NB_BEGIN; 519 case PLIP_NB_2: 520 break; 521 } 522 return OK; 523 } 524 525 /* 526 * Determine the packet's protocol ID. The rule here is that we 527 * assume 802.3 if the type field is short enough to be a length. 528 * This is normal practice and works for any 'now in use' protocol. 529 * 530 * PLIP is ethernet ish but the daddr might not be valid if unicast. 531 * PLIP fortunately has no bus architecture (its Point-to-point). 532 * 533 * We can't fix the daddr thing as that quirk (more bug) is embedded 534 * in far too many old systems not all even running Linux. 535 */ 536 537 static __be16 plip_type_trans(struct sk_buff *skb, struct net_device *dev) 538 { 539 struct ethhdr *eth; 540 unsigned char *rawp; 541 542 skb_reset_mac_header(skb); 543 skb_pull(skb,dev->hard_header_len); 544 eth = eth_hdr(skb); 545 546 if(is_multicast_ether_addr(eth->h_dest)) 547 { 548 if(ether_addr_equal_64bits(eth->h_dest, dev->broadcast)) 549 skb->pkt_type=PACKET_BROADCAST; 550 else 551 skb->pkt_type=PACKET_MULTICAST; 552 } 553 554 /* 555 * This ALLMULTI check should be redundant by 1.4 556 * so don't forget to remove it. 557 */ 558 559 if (ntohs(eth->h_proto) >= ETH_P_802_3_MIN) 560 return eth->h_proto; 561 562 rawp = skb->data; 563 564 /* 565 * This is a magic hack to spot IPX packets. Older Novell breaks 566 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 567 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 568 * won't work for fault tolerant netware but does for the rest. 569 */ 570 if (*(unsigned short *)rawp == 0xFFFF) 571 return htons(ETH_P_802_3); 572 573 /* 574 * Real 802.2 LLC 575 */ 576 return htons(ETH_P_802_2); 577 } 578 579 /* PLIP_RECEIVE_PACKET --- receive a packet */ 580 static int 581 plip_receive_packet(struct net_device *dev, struct net_local *nl, 582 struct plip_local *snd, struct plip_local *rcv) 583 { 584 unsigned short nibble_timeout = nl->nibble; 585 unsigned char *lbuf; 586 587 switch (rcv->state) { 588 case PLIP_PK_TRIGGER: 589 DISABLE(dev->irq); 590 /* Don't need to synchronize irq, as we can safely ignore it */ 591 disable_parport_interrupts (dev); 592 write_data (dev, 0x01); /* send ACK */ 593 if (net_debug > 2) 594 printk(KERN_DEBUG "%s: receive start\n", dev->name); 595 rcv->state = PLIP_PK_LENGTH_LSB; 596 rcv->nibble = PLIP_NB_BEGIN; 597 /* fall through */ 598 599 case PLIP_PK_LENGTH_LSB: 600 if (snd->state != PLIP_PK_DONE) { 601 if (plip_receive(nl->trigger, dev, 602 &rcv->nibble, &rcv->length.b.lsb)) { 603 /* collision, here dev->tbusy == 1 */ 604 rcv->state = PLIP_PK_DONE; 605 nl->is_deferred = 1; 606 nl->connection = PLIP_CN_SEND; 607 schedule_delayed_work(&nl->deferred, 1); 608 enable_parport_interrupts (dev); 609 ENABLE(dev->irq); 610 return OK; 611 } 612 } else { 613 if (plip_receive(nibble_timeout, dev, 614 &rcv->nibble, &rcv->length.b.lsb)) 615 return TIMEOUT; 616 } 617 rcv->state = PLIP_PK_LENGTH_MSB; 618 /* fall through */ 619 620 case PLIP_PK_LENGTH_MSB: 621 if (plip_receive(nibble_timeout, dev, 622 &rcv->nibble, &rcv->length.b.msb)) 623 return TIMEOUT; 624 if (rcv->length.h > dev->mtu + dev->hard_header_len || 625 rcv->length.h < 8) { 626 printk(KERN_WARNING "%s: bogus packet size %d.\n", dev->name, rcv->length.h); 627 return ERROR; 628 } 629 /* Malloc up new buffer. */ 630 rcv->skb = dev_alloc_skb(rcv->length.h + 2); 631 if (rcv->skb == NULL) { 632 printk(KERN_ERR "%s: Memory squeeze.\n", dev->name); 633 return ERROR; 634 } 635 skb_reserve(rcv->skb, 2); /* Align IP on 16 byte boundaries */ 636 skb_put(rcv->skb,rcv->length.h); 637 rcv->skb->dev = dev; 638 rcv->state = PLIP_PK_DATA; 639 rcv->byte = 0; 640 rcv->checksum = 0; 641 /* fall through */ 642 643 case PLIP_PK_DATA: 644 lbuf = rcv->skb->data; 645 do { 646 if (plip_receive(nibble_timeout, dev, 647 &rcv->nibble, &lbuf[rcv->byte])) 648 return TIMEOUT; 649 } while (++rcv->byte < rcv->length.h); 650 do { 651 rcv->checksum += lbuf[--rcv->byte]; 652 } while (rcv->byte); 653 rcv->state = PLIP_PK_CHECKSUM; 654 /* fall through */ 655 656 case PLIP_PK_CHECKSUM: 657 if (plip_receive(nibble_timeout, dev, 658 &rcv->nibble, &rcv->data)) 659 return TIMEOUT; 660 if (rcv->data != rcv->checksum) { 661 dev->stats.rx_crc_errors++; 662 if (net_debug) 663 printk(KERN_DEBUG "%s: checksum error\n", dev->name); 664 return ERROR; 665 } 666 rcv->state = PLIP_PK_DONE; 667 /* fall through */ 668 669 case PLIP_PK_DONE: 670 /* Inform the upper layer for the arrival of a packet. */ 671 rcv->skb->protocol=plip_type_trans(rcv->skb, dev); 672 netif_rx_ni(rcv->skb); 673 dev->stats.rx_bytes += rcv->length.h; 674 dev->stats.rx_packets++; 675 rcv->skb = NULL; 676 if (net_debug > 2) 677 printk(KERN_DEBUG "%s: receive end\n", dev->name); 678 679 /* Close the connection. */ 680 write_data (dev, 0x00); 681 spin_lock_irq(&nl->lock); 682 if (snd->state != PLIP_PK_DONE) { 683 nl->connection = PLIP_CN_SEND; 684 spin_unlock_irq(&nl->lock); 685 schedule_work(&nl->immediate); 686 enable_parport_interrupts (dev); 687 ENABLE(dev->irq); 688 return OK; 689 } else { 690 nl->connection = PLIP_CN_NONE; 691 spin_unlock_irq(&nl->lock); 692 enable_parport_interrupts (dev); 693 ENABLE(dev->irq); 694 return OK; 695 } 696 } 697 return OK; 698 } 699 700 /* PLIP_SEND --- send a byte (two nibbles) 701 Returns OK on success, TIMEOUT when timeout */ 702 static inline int 703 plip_send(unsigned short nibble_timeout, struct net_device *dev, 704 enum plip_nibble_state *ns_p, unsigned char data) 705 { 706 unsigned char c0; 707 unsigned int cx; 708 709 switch (*ns_p) { 710 case PLIP_NB_BEGIN: 711 write_data (dev, data & 0x0f); 712 *ns_p = PLIP_NB_1; 713 /* fall through */ 714 715 case PLIP_NB_1: 716 write_data (dev, 0x10 | (data & 0x0f)); 717 cx = nibble_timeout; 718 while (1) { 719 c0 = read_status(dev); 720 if ((c0 & 0x80) == 0) 721 break; 722 if (--cx == 0) 723 return TIMEOUT; 724 udelay(PLIP_DELAY_UNIT); 725 } 726 write_data (dev, 0x10 | (data >> 4)); 727 *ns_p = PLIP_NB_2; 728 /* fall through */ 729 730 case PLIP_NB_2: 731 write_data (dev, (data >> 4)); 732 cx = nibble_timeout; 733 while (1) { 734 c0 = read_status(dev); 735 if (c0 & 0x80) 736 break; 737 if (--cx == 0) 738 return TIMEOUT; 739 udelay(PLIP_DELAY_UNIT); 740 } 741 *ns_p = PLIP_NB_BEGIN; 742 return OK; 743 } 744 return OK; 745 } 746 747 /* PLIP_SEND_PACKET --- send a packet */ 748 static int 749 plip_send_packet(struct net_device *dev, struct net_local *nl, 750 struct plip_local *snd, struct plip_local *rcv) 751 { 752 unsigned short nibble_timeout = nl->nibble; 753 unsigned char *lbuf; 754 unsigned char c0; 755 unsigned int cx; 756 757 if (snd->skb == NULL || (lbuf = snd->skb->data) == NULL) { 758 printk(KERN_DEBUG "%s: send skb lost\n", dev->name); 759 snd->state = PLIP_PK_DONE; 760 snd->skb = NULL; 761 return ERROR; 762 } 763 764 switch (snd->state) { 765 case PLIP_PK_TRIGGER: 766 if ((read_status(dev) & 0xf8) != 0x80) 767 return HS_TIMEOUT; 768 769 /* Trigger remote rx interrupt. */ 770 write_data (dev, 0x08); 771 cx = nl->trigger; 772 while (1) { 773 udelay(PLIP_DELAY_UNIT); 774 spin_lock_irq(&nl->lock); 775 if (nl->connection == PLIP_CN_RECEIVE) { 776 spin_unlock_irq(&nl->lock); 777 /* Interrupted. */ 778 dev->stats.collisions++; 779 return OK; 780 } 781 c0 = read_status(dev); 782 if (c0 & 0x08) { 783 spin_unlock_irq(&nl->lock); 784 DISABLE(dev->irq); 785 synchronize_irq(dev->irq); 786 if (nl->connection == PLIP_CN_RECEIVE) { 787 /* Interrupted. 788 We don't need to enable irq, 789 as it is soon disabled. */ 790 /* Yes, we do. New variant of 791 {enable,disable}_irq *counts* 792 them. -- AV */ 793 ENABLE(dev->irq); 794 dev->stats.collisions++; 795 return OK; 796 } 797 disable_parport_interrupts (dev); 798 if (net_debug > 2) 799 printk(KERN_DEBUG "%s: send start\n", dev->name); 800 snd->state = PLIP_PK_LENGTH_LSB; 801 snd->nibble = PLIP_NB_BEGIN; 802 nl->timeout_count = 0; 803 break; 804 } 805 spin_unlock_irq(&nl->lock); 806 if (--cx == 0) { 807 write_data (dev, 0x00); 808 return HS_TIMEOUT; 809 } 810 } 811 812 case PLIP_PK_LENGTH_LSB: 813 if (plip_send(nibble_timeout, dev, 814 &snd->nibble, snd->length.b.lsb)) 815 return TIMEOUT; 816 snd->state = PLIP_PK_LENGTH_MSB; 817 /* fall through */ 818 819 case PLIP_PK_LENGTH_MSB: 820 if (plip_send(nibble_timeout, dev, 821 &snd->nibble, snd->length.b.msb)) 822 return TIMEOUT; 823 snd->state = PLIP_PK_DATA; 824 snd->byte = 0; 825 snd->checksum = 0; 826 /* fall through */ 827 828 case PLIP_PK_DATA: 829 do { 830 if (plip_send(nibble_timeout, dev, 831 &snd->nibble, lbuf[snd->byte])) 832 return TIMEOUT; 833 } while (++snd->byte < snd->length.h); 834 do { 835 snd->checksum += lbuf[--snd->byte]; 836 } while (snd->byte); 837 snd->state = PLIP_PK_CHECKSUM; 838 /* fall through */ 839 840 case PLIP_PK_CHECKSUM: 841 if (plip_send(nibble_timeout, dev, 842 &snd->nibble, snd->checksum)) 843 return TIMEOUT; 844 845 dev->stats.tx_bytes += snd->skb->len; 846 dev_kfree_skb(snd->skb); 847 dev->stats.tx_packets++; 848 snd->state = PLIP_PK_DONE; 849 /* fall through */ 850 851 case PLIP_PK_DONE: 852 /* Close the connection */ 853 write_data (dev, 0x00); 854 snd->skb = NULL; 855 if (net_debug > 2) 856 printk(KERN_DEBUG "%s: send end\n", dev->name); 857 nl->connection = PLIP_CN_CLOSING; 858 nl->is_deferred = 1; 859 schedule_delayed_work(&nl->deferred, 1); 860 enable_parport_interrupts (dev); 861 ENABLE(dev->irq); 862 return OK; 863 } 864 return OK; 865 } 866 867 static int 868 plip_connection_close(struct net_device *dev, struct net_local *nl, 869 struct plip_local *snd, struct plip_local *rcv) 870 { 871 spin_lock_irq(&nl->lock); 872 if (nl->connection == PLIP_CN_CLOSING) { 873 nl->connection = PLIP_CN_NONE; 874 netif_wake_queue (dev); 875 } 876 spin_unlock_irq(&nl->lock); 877 if (nl->should_relinquish) { 878 nl->should_relinquish = nl->port_owner = 0; 879 parport_release(nl->pardev); 880 } 881 return OK; 882 } 883 884 /* PLIP_ERROR --- wait till other end settled */ 885 static int 886 plip_error(struct net_device *dev, struct net_local *nl, 887 struct plip_local *snd, struct plip_local *rcv) 888 { 889 unsigned char status; 890 891 status = read_status(dev); 892 if ((status & 0xf8) == 0x80) { 893 if (net_debug > 2) 894 printk(KERN_DEBUG "%s: reset interface.\n", dev->name); 895 nl->connection = PLIP_CN_NONE; 896 nl->should_relinquish = 0; 897 netif_start_queue (dev); 898 enable_parport_interrupts (dev); 899 ENABLE(dev->irq); 900 netif_wake_queue (dev); 901 } else { 902 nl->is_deferred = 1; 903 schedule_delayed_work(&nl->deferred, 1); 904 } 905 906 return OK; 907 } 908 909 /* Handle the parallel port interrupts. */ 910 static void 911 plip_interrupt(void *dev_id) 912 { 913 struct net_device *dev = dev_id; 914 struct net_local *nl; 915 struct plip_local *rcv; 916 unsigned char c0; 917 unsigned long flags; 918 919 nl = netdev_priv(dev); 920 rcv = &nl->rcv_data; 921 922 spin_lock_irqsave (&nl->lock, flags); 923 924 c0 = read_status(dev); 925 if ((c0 & 0xf8) != 0xc0) { 926 if ((dev->irq != -1) && (net_debug > 1)) 927 printk(KERN_DEBUG "%s: spurious interrupt\n", dev->name); 928 spin_unlock_irqrestore (&nl->lock, flags); 929 return; 930 } 931 932 if (net_debug > 3) 933 printk(KERN_DEBUG "%s: interrupt.\n", dev->name); 934 935 switch (nl->connection) { 936 case PLIP_CN_CLOSING: 937 netif_wake_queue (dev); 938 /* fall through */ 939 case PLIP_CN_NONE: 940 case PLIP_CN_SEND: 941 rcv->state = PLIP_PK_TRIGGER; 942 nl->connection = PLIP_CN_RECEIVE; 943 nl->timeout_count = 0; 944 schedule_work(&nl->immediate); 945 break; 946 947 case PLIP_CN_RECEIVE: 948 /* May occur because there is race condition 949 around test and set of dev->interrupt. 950 Ignore this interrupt. */ 951 break; 952 953 case PLIP_CN_ERROR: 954 printk(KERN_ERR "%s: receive interrupt in error state\n", dev->name); 955 break; 956 } 957 958 spin_unlock_irqrestore(&nl->lock, flags); 959 } 960 961 static int 962 plip_tx_packet(struct sk_buff *skb, struct net_device *dev) 963 { 964 struct net_local *nl = netdev_priv(dev); 965 struct plip_local *snd = &nl->snd_data; 966 967 if (netif_queue_stopped(dev)) 968 return NETDEV_TX_BUSY; 969 970 /* We may need to grab the bus */ 971 if (!nl->port_owner) { 972 if (parport_claim(nl->pardev)) 973 return NETDEV_TX_BUSY; 974 nl->port_owner = 1; 975 } 976 977 netif_stop_queue (dev); 978 979 if (skb->len > dev->mtu + dev->hard_header_len) { 980 printk(KERN_WARNING "%s: packet too big, %d.\n", dev->name, (int)skb->len); 981 netif_start_queue (dev); 982 return NETDEV_TX_BUSY; 983 } 984 985 if (net_debug > 2) 986 printk(KERN_DEBUG "%s: send request\n", dev->name); 987 988 spin_lock_irq(&nl->lock); 989 snd->skb = skb; 990 snd->length.h = skb->len; 991 snd->state = PLIP_PK_TRIGGER; 992 if (nl->connection == PLIP_CN_NONE) { 993 nl->connection = PLIP_CN_SEND; 994 nl->timeout_count = 0; 995 } 996 schedule_work(&nl->immediate); 997 spin_unlock_irq(&nl->lock); 998 999 return NETDEV_TX_OK; 1000 } 1001 1002 static void 1003 plip_rewrite_address(const struct net_device *dev, struct ethhdr *eth) 1004 { 1005 const struct in_device *in_dev; 1006 1007 rcu_read_lock(); 1008 in_dev = __in_dev_get_rcu(dev); 1009 if (in_dev) { 1010 /* Any address will do - we take the first */ 1011 const struct in_ifaddr *ifa = in_dev->ifa_list; 1012 if (ifa) { 1013 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 1014 memset(eth->h_dest, 0xfc, 2); 1015 memcpy(eth->h_dest+2, &ifa->ifa_address, 4); 1016 } 1017 } 1018 rcu_read_unlock(); 1019 } 1020 1021 static int 1022 plip_hard_header(struct sk_buff *skb, struct net_device *dev, 1023 unsigned short type, const void *daddr, 1024 const void *saddr, unsigned len) 1025 { 1026 int ret; 1027 1028 ret = eth_header(skb, dev, type, daddr, saddr, len); 1029 if (ret >= 0) 1030 plip_rewrite_address (dev, (struct ethhdr *)skb->data); 1031 1032 return ret; 1033 } 1034 1035 static int plip_hard_header_cache(const struct neighbour *neigh, 1036 struct hh_cache *hh, __be16 type) 1037 { 1038 int ret; 1039 1040 ret = eth_header_cache(neigh, hh, type); 1041 if (ret == 0) { 1042 struct ethhdr *eth; 1043 1044 eth = (struct ethhdr*)(((u8*)hh->hh_data) + 1045 HH_DATA_OFF(sizeof(*eth))); 1046 plip_rewrite_address (neigh->dev, eth); 1047 } 1048 1049 return ret; 1050 } 1051 1052 /* Open/initialize the board. This is called (in the current kernel) 1053 sometime after booting when the 'ifconfig' program is run. 1054 1055 This routine gets exclusive access to the parallel port by allocating 1056 its IRQ line. 1057 */ 1058 static int 1059 plip_open(struct net_device *dev) 1060 { 1061 struct net_local *nl = netdev_priv(dev); 1062 struct in_device *in_dev; 1063 1064 /* Grab the port */ 1065 if (!nl->port_owner) { 1066 if (parport_claim(nl->pardev)) return -EAGAIN; 1067 nl->port_owner = 1; 1068 } 1069 1070 nl->should_relinquish = 0; 1071 1072 /* Clear the data port. */ 1073 write_data (dev, 0x00); 1074 1075 /* Enable rx interrupt. */ 1076 enable_parport_interrupts (dev); 1077 if (dev->irq == -1) 1078 { 1079 atomic_set (&nl->kill_timer, 0); 1080 schedule_delayed_work(&nl->timer, 1); 1081 } 1082 1083 /* Initialize the state machine. */ 1084 nl->rcv_data.state = nl->snd_data.state = PLIP_PK_DONE; 1085 nl->rcv_data.skb = nl->snd_data.skb = NULL; 1086 nl->connection = PLIP_CN_NONE; 1087 nl->is_deferred = 0; 1088 1089 /* Fill in the MAC-level header. 1090 We used to abuse dev->broadcast to store the point-to-point 1091 MAC address, but we no longer do it. Instead, we fetch the 1092 interface address whenever it is needed, which is cheap enough 1093 because we use the hh_cache. Actually, abusing dev->broadcast 1094 didn't work, because when using plip_open the point-to-point 1095 address isn't yet known. 1096 PLIP doesn't have a real MAC address, but we need it to be 1097 DOS compatible, and to properly support taps (otherwise, 1098 when the device address isn't identical to the address of a 1099 received frame, the kernel incorrectly drops it). */ 1100 1101 in_dev=__in_dev_get_rtnl(dev); 1102 if (in_dev) { 1103 /* Any address will do - we take the first. We already 1104 have the first two bytes filled with 0xfc, from 1105 plip_init_dev(). */ 1106 struct in_ifaddr *ifa=in_dev->ifa_list; 1107 if (ifa != NULL) { 1108 memcpy(dev->dev_addr+2, &ifa->ifa_local, 4); 1109 } 1110 } 1111 1112 netif_start_queue (dev); 1113 1114 return 0; 1115 } 1116 1117 /* The inverse routine to plip_open (). */ 1118 static int 1119 plip_close(struct net_device *dev) 1120 { 1121 struct net_local *nl = netdev_priv(dev); 1122 struct plip_local *snd = &nl->snd_data; 1123 struct plip_local *rcv = &nl->rcv_data; 1124 1125 netif_stop_queue (dev); 1126 DISABLE(dev->irq); 1127 synchronize_irq(dev->irq); 1128 1129 if (dev->irq == -1) 1130 { 1131 init_completion(&nl->killed_timer_cmp); 1132 atomic_set (&nl->kill_timer, 1); 1133 wait_for_completion(&nl->killed_timer_cmp); 1134 } 1135 1136 #ifdef NOTDEF 1137 outb(0x00, PAR_DATA(dev)); 1138 #endif 1139 nl->is_deferred = 0; 1140 nl->connection = PLIP_CN_NONE; 1141 if (nl->port_owner) { 1142 parport_release(nl->pardev); 1143 nl->port_owner = 0; 1144 } 1145 1146 snd->state = PLIP_PK_DONE; 1147 if (snd->skb) { 1148 dev_kfree_skb(snd->skb); 1149 snd->skb = NULL; 1150 } 1151 rcv->state = PLIP_PK_DONE; 1152 if (rcv->skb) { 1153 kfree_skb(rcv->skb); 1154 rcv->skb = NULL; 1155 } 1156 1157 #ifdef NOTDEF 1158 /* Reset. */ 1159 outb(0x00, PAR_CONTROL(dev)); 1160 #endif 1161 return 0; 1162 } 1163 1164 static int 1165 plip_preempt(void *handle) 1166 { 1167 struct net_device *dev = (struct net_device *)handle; 1168 struct net_local *nl = netdev_priv(dev); 1169 1170 /* Stand our ground if a datagram is on the wire */ 1171 if (nl->connection != PLIP_CN_NONE) { 1172 nl->should_relinquish = 1; 1173 return 1; 1174 } 1175 1176 nl->port_owner = 0; /* Remember that we released the bus */ 1177 return 0; 1178 } 1179 1180 static void 1181 plip_wakeup(void *handle) 1182 { 1183 struct net_device *dev = (struct net_device *)handle; 1184 struct net_local *nl = netdev_priv(dev); 1185 1186 if (nl->port_owner) { 1187 /* Why are we being woken up? */ 1188 printk(KERN_DEBUG "%s: why am I being woken up?\n", dev->name); 1189 if (!parport_claim(nl->pardev)) 1190 /* bus_owner is already set (but why?) */ 1191 printk(KERN_DEBUG "%s: I'm broken.\n", dev->name); 1192 else 1193 return; 1194 } 1195 1196 if (!(dev->flags & IFF_UP)) 1197 /* Don't need the port when the interface is down */ 1198 return; 1199 1200 if (!parport_claim(nl->pardev)) { 1201 nl->port_owner = 1; 1202 /* Clear the data port. */ 1203 write_data (dev, 0x00); 1204 } 1205 } 1206 1207 static int 1208 plip_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1209 { 1210 struct net_local *nl = netdev_priv(dev); 1211 struct plipconf *pc = (struct plipconf *) &rq->ifr_ifru; 1212 1213 if (cmd != SIOCDEVPLIP) 1214 return -EOPNOTSUPP; 1215 1216 switch(pc->pcmd) { 1217 case PLIP_GET_TIMEOUT: 1218 pc->trigger = nl->trigger; 1219 pc->nibble = nl->nibble; 1220 break; 1221 case PLIP_SET_TIMEOUT: 1222 if(!capable(CAP_NET_ADMIN)) 1223 return -EPERM; 1224 nl->trigger = pc->trigger; 1225 nl->nibble = pc->nibble; 1226 break; 1227 default: 1228 return -EOPNOTSUPP; 1229 } 1230 return 0; 1231 } 1232 1233 static int parport[PLIP_MAX] = { [0 ... PLIP_MAX-1] = -1 }; 1234 static int timid; 1235 1236 module_param_array(parport, int, NULL, 0); 1237 module_param(timid, int, 0); 1238 MODULE_PARM_DESC(parport, "List of parport device numbers to use by plip"); 1239 1240 static struct net_device *dev_plip[PLIP_MAX] = { NULL, }; 1241 1242 static inline int 1243 plip_searchfor(int list[], int a) 1244 { 1245 int i; 1246 for (i = 0; i < PLIP_MAX && list[i] != -1; i++) { 1247 if (list[i] == a) return 1; 1248 } 1249 return 0; 1250 } 1251 1252 /* plip_attach() is called (by the parport code) when a port is 1253 * available to use. */ 1254 static void plip_attach (struct parport *port) 1255 { 1256 static int unit; 1257 struct net_device *dev; 1258 struct net_local *nl; 1259 char name[IFNAMSIZ]; 1260 struct pardev_cb plip_cb; 1261 1262 if ((parport[0] == -1 && (!timid || !port->devices)) || 1263 plip_searchfor(parport, port->number)) { 1264 if (unit == PLIP_MAX) { 1265 printk(KERN_ERR "plip: too many devices\n"); 1266 return; 1267 } 1268 1269 sprintf(name, "plip%d", unit); 1270 dev = alloc_etherdev(sizeof(struct net_local)); 1271 if (!dev) 1272 return; 1273 1274 strcpy(dev->name, name); 1275 1276 dev->irq = port->irq; 1277 dev->base_addr = port->base; 1278 if (port->irq == -1) { 1279 printk(KERN_INFO "plip: %s has no IRQ. Using IRQ-less mode," 1280 "which is fairly inefficient!\n", port->name); 1281 } 1282 1283 nl = netdev_priv(dev); 1284 nl->dev = dev; 1285 1286 memset(&plip_cb, 0, sizeof(plip_cb)); 1287 plip_cb.private = dev; 1288 plip_cb.preempt = plip_preempt; 1289 plip_cb.wakeup = plip_wakeup; 1290 plip_cb.irq_func = plip_interrupt; 1291 1292 nl->pardev = parport_register_dev_model(port, dev->name, 1293 &plip_cb, unit); 1294 1295 if (!nl->pardev) { 1296 printk(KERN_ERR "%s: parport_register failed\n", name); 1297 goto err_free_dev; 1298 } 1299 1300 plip_init_netdev(dev); 1301 1302 if (register_netdev(dev)) { 1303 printk(KERN_ERR "%s: network register failed\n", name); 1304 goto err_parport_unregister; 1305 } 1306 1307 printk(KERN_INFO "%s", version); 1308 if (dev->irq != -1) 1309 printk(KERN_INFO "%s: Parallel port at %#3lx, " 1310 "using IRQ %d.\n", 1311 dev->name, dev->base_addr, dev->irq); 1312 else 1313 printk(KERN_INFO "%s: Parallel port at %#3lx, " 1314 "not using IRQ.\n", 1315 dev->name, dev->base_addr); 1316 dev_plip[unit++] = dev; 1317 } 1318 return; 1319 1320 err_parport_unregister: 1321 parport_unregister_device(nl->pardev); 1322 err_free_dev: 1323 free_netdev(dev); 1324 } 1325 1326 /* plip_detach() is called (by the parport code) when a port is 1327 * no longer available to use. */ 1328 static void plip_detach (struct parport *port) 1329 { 1330 /* Nothing to do */ 1331 } 1332 1333 static int plip_probe(struct pardevice *par_dev) 1334 { 1335 struct device_driver *drv = par_dev->dev.driver; 1336 int len = strlen(drv->name); 1337 1338 if (strncmp(par_dev->name, drv->name, len)) 1339 return -ENODEV; 1340 1341 return 0; 1342 } 1343 1344 static struct parport_driver plip_driver = { 1345 .name = "plip", 1346 .probe = plip_probe, 1347 .match_port = plip_attach, 1348 .detach = plip_detach, 1349 .devmodel = true, 1350 }; 1351 1352 static void __exit plip_cleanup_module (void) 1353 { 1354 struct net_device *dev; 1355 int i; 1356 1357 for (i=0; i < PLIP_MAX; i++) { 1358 if ((dev = dev_plip[i])) { 1359 struct net_local *nl = netdev_priv(dev); 1360 unregister_netdev(dev); 1361 if (nl->port_owner) 1362 parport_release(nl->pardev); 1363 parport_unregister_device(nl->pardev); 1364 free_netdev(dev); 1365 dev_plip[i] = NULL; 1366 } 1367 } 1368 1369 parport_unregister_driver(&plip_driver); 1370 } 1371 1372 #ifndef MODULE 1373 1374 static int parport_ptr; 1375 1376 static int __init plip_setup(char *str) 1377 { 1378 int ints[4]; 1379 1380 str = get_options(str, ARRAY_SIZE(ints), ints); 1381 1382 /* Ugh. */ 1383 if (!strncmp(str, "parport", 7)) { 1384 int n = simple_strtoul(str+7, NULL, 10); 1385 if (parport_ptr < PLIP_MAX) 1386 parport[parport_ptr++] = n; 1387 else 1388 printk(KERN_INFO "plip: too many ports, %s ignored.\n", 1389 str); 1390 } else if (!strcmp(str, "timid")) { 1391 timid = 1; 1392 } else { 1393 if (ints[0] == 0 || ints[1] == 0) { 1394 /* disable driver on "plip=" or "plip=0" */ 1395 parport[0] = -2; 1396 } else { 1397 printk(KERN_WARNING "warning: 'plip=0x%x' ignored\n", 1398 ints[1]); 1399 } 1400 } 1401 return 1; 1402 } 1403 1404 __setup("plip=", plip_setup); 1405 1406 #endif /* !MODULE */ 1407 1408 static int __init plip_init (void) 1409 { 1410 if (parport[0] == -2) 1411 return 0; 1412 1413 if (parport[0] != -1 && timid) { 1414 printk(KERN_WARNING "plip: warning, ignoring `timid' since specific ports given.\n"); 1415 timid = 0; 1416 } 1417 1418 if (parport_register_driver (&plip_driver)) { 1419 printk (KERN_WARNING "plip: couldn't register driver\n"); 1420 return 1; 1421 } 1422 1423 return 0; 1424 } 1425 1426 module_init(plip_init); 1427 module_exit(plip_cleanup_module); 1428 MODULE_LICENSE("GPL"); 1429