aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/plip.c
blob: 2cfab4b366549c52470597eaf36ff51bc97aba5c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
/* $Id: plip.c,v 1.3.6.2 1997/04/16 15:07:56 phil Exp $ */
/* PLIP: A parallel port "network" driver for Linux. */
/* This driver is for parallel port with 5-bit cable (LapLink (R) cable). */
/*
 * Authors:	Donald Becker <becker@scyld.com>
 *		Tommy Thorn <thorn@daimi.aau.dk>
 *		Tanabe Hiroyasu <hiro@sanpo.t.u-tokyo.ac.jp>
 *		Alan Cox <gw4pts@gw4pts.ampr.org>
 *		Peter Bauer <100136.3530@compuserve.com>
 *		Niibe Yutaka <gniibe@mri.co.jp>
 *		Nimrod Zimerman <zimerman@mailandnews.com>
 *
 * Enhancements:
 *		Modularization and ifreq/ifmap support by Alan Cox.
 *		Rewritten by Niibe Yutaka.
 *		parport-sharing awareness code by Philip Blundell.
 *		SMP locking by Niibe Yutaka.
 *		Support for parallel ports with no IRQ (poll mode),
 *		Modifications to use the parallel port API
 *		by Nimrod Zimerman.
 *
 * Fixes:
 *		Niibe Yutaka
 *		  - Module initialization.
 *		  - MTU fix.
 *		  - Make sure other end is OK, before sending a packet.
 *		  - Fix immediate timer problem.
 *
 *		Al Viro
 *		  - Changed {enable,disable}_irq handling to make it work
 *		    with new ("stack") semantics.
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */

/*
 * Original version and the name 'PLIP' from Donald Becker <becker@scyld.com>
 * inspired by Russ Nelson's parallel port packet driver.
 *
 * NOTE:
 *     Tanabe Hiroyasu had changed the protocol, and it was in Linux v1.0.
 *     Because of the necessity to communicate to DOS machines with the
 *     Crynwr packet driver, Peter Bauer changed the protocol again
 *     back to original protocol.
 *
 *     This version follows original PLIP protocol.
 *     So, this PLIP can't communicate the PLIP of Linux v1.0.
 */

/*
 *     To use with DOS box, please do (Turn on ARP switch):
 *	# ifconfig plip[0-2] arp
 */
static const char version[] = "NET3 PLIP version 2.4-parport gniibe@mri.co.jp\n";

/*
  Sources:
	Ideas and protocols came from Russ Nelson's <nelson@crynwr.com>
	"parallel.asm" parallel port packet driver.

  The "Crynwr" parallel port standard specifies the following protocol:
    Trigger by sending nibble '0x8' (this causes interrupt on other end)
    count-low octet
    count-high octet
    ... data octets
    checksum octet
  Each octet is sent as <wait for rx. '0x1?'> <send 0x10+(octet&0x0F)>
			<wait for rx. '0x0?'> <send 0x00+((octet>>4)&0x0F)>

  The packet is encapsulated as if it were ethernet.

  The cable used is a de facto standard parallel null cable -- sold as
  a "LapLink" cable by various places.  You'll need a 12-conductor cable to
  make one yourself.  The wiring is:
    SLCTIN	17 - 17
    GROUND	25 - 25
    D0->ERROR	2 - 15		15 - 2
    D1->SLCT	3 - 13		13 - 3
    D2->PAPOUT	4 - 12		12 - 4
    D3->ACK	5 - 10		10 - 5
    D4->BUSY	6 - 11		11 - 6
  Do not connect the other pins.  They are
    D5,D6,D7 are 7,8,9
    STROBE is 1, FEED is 14, INIT is 16
    extra grounds are 18,19,20,21,22,23,24
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/inetdevice.h>
#include <linux/skbuff.h>
#include <linux/if_plip.h>
#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/parport.h>
#include <linux/bitops.h>

#include <net/neighbour.h>

#include <asm/system.h>
#include <asm/irq.h>
#include <asm/byteorder.h>
#include <asm/semaphore.h>

/* Maximum number of devices to support. */
#define PLIP_MAX  8

/* Use 0 for production, 1 for verification, >2 for debug */
#ifndef NET_DEBUG
#define NET_DEBUG 1
#endif
static const unsigned int net_debug = NET_DEBUG;

#define ENABLE(irq)  if (irq != -1) enable_irq(irq)
#define DISABLE(irq) if (irq != -1) disable_irq(irq)

/* In micro second */
#define PLIP_DELAY_UNIT		   1

/* Connection time out = PLIP_TRIGGER_WAIT * PLIP_DELAY_UNIT usec */
#define PLIP_TRIGGER_WAIT	 500

/* Nibble time out = PLIP_NIBBLE_WAIT * PLIP_DELAY_UNIT usec */
#define PLIP_NIBBLE_WAIT        3000

/* Bottom halves */
static void plip_kick_bh(struct work_struct *work);
static void plip_bh(struct work_struct *work);
static void plip_timer_bh(struct work_struct *work);

/* Interrupt handler */
static void plip_interrupt(int irq, void *dev_id);

/* Functions for DEV methods */
static int plip_tx_packet(struct sk_buff *skb, struct net_device *dev);
static int plip_hard_header(struct sk_buff *skb, struct net_device *dev,
                            unsigned short type, void *daddr,
                            void *saddr, unsigned len);
static int plip_hard_header_cache(struct neighbour *neigh,
                                  struct hh_cache *hh);
static int plip_open(struct net_device *dev);
static int plip_close(struct net_device *dev);
static struct net_device_stats *plip_get_stats(struct net_device *dev);
static int plip_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
static int plip_preempt(void *handle);
static void plip_wakeup(void *handle);

enum plip_connection_state {
	PLIP_CN_NONE=0,
	PLIP_CN_RECEIVE,
	PLIP_CN_SEND,
	PLIP_CN_CLOSING,
	PLIP_CN_ERROR
};

enum plip_packet_state {
	PLIP_PK_DONE=0,
	PLIP_PK_TRIGGER,
	PLIP_PK_LENGTH_LSB,
	PLIP_PK_LENGTH_MSB,
	PLIP_PK_DATA,
	PLIP_PK_CHECKSUM
};

enum plip_nibble_state {
	PLIP_NB_BEGIN,
	PLIP_NB_1,
	PLIP_NB_2,
};

struct plip_local {
	enum plip_packet_state state;
	enum plip_nibble_state nibble;
	union {
		struct {
#if defined(__LITTLE_ENDIAN)
			unsigned char lsb;
			unsigned char msb;
#elif defined(__BIG_ENDIAN)
			unsigned char msb;
			unsigned char lsb;
#else
#error	"Please fix the endianness defines in <asm/byteorder.h>"
#endif
		} b;
		unsigned short h;
	} length;
	unsigned short byte;
	unsigned char  checksum;
	unsigned char  data;
	struct sk_buff *skb;
};

struct net_local {
	struct net_device_stats enet_stats;
	struct net_device *dev;
	struct work_struct immediate;
	struct delayed_work deferred;
	struct delayed_work timer;
	struct plip_local snd_data;
	struct plip_local rcv_data;
	struct pardevice *pardev;
	unsigned long  trigger;
	unsigned long  nibble;
	enum plip_connection_state connection;
	unsigned short timeout_count;
	int is_deferred;
	int port_owner;
	int should_relinquish;
	int (*orig_hard_header)(struct sk_buff *skb, struct net_device *dev,
	                        unsigned short type, void *daddr,
	                        void *saddr, unsigned len);
	int (*orig_hard_header_cache)(struct neighbour *neigh,
	                              struct hh_cache *hh);
	spinlock_t lock;
	atomic_t kill_timer;
	struct semaphore killed_timer_sem;
};

static inline void enable_parport_interrupts (struct net_device *dev)
{
	if (dev->irq != -1)
	{
		struct parport *port =
		   ((struct net_local *)dev->priv)->pardev->port;
		port->ops->enable_irq (port);
	}
}

static inline void disable_parport_interrupts (struct net_device *dev)
{
	if (dev->irq != -1)
	{
		struct parport *port =
		   ((struct net_local *)dev->priv)->pardev->port;
		port->ops->disable_irq (port);
	}
}

static inline void write_data (struct net_device *dev, unsigned char data)
{
	struct parport *port =
	   ((struct net_local *)dev->priv)->pardev->port;

	port->ops->write_data (port, data);
}

static inline unsigned char read_status (struct net_device *dev)
{
	struct parport *port =
	   ((struct net_local *)dev->priv)->pardev->port;

	return port->ops->read_status (port);
}

/* Entry point of PLIP driver.
   Probe the hardware, and register/initialize the driver.

   PLIP is rather weird, because of the way it interacts with the parport
   system.  It is _not_ initialised from Space.c.  Instead, plip_init()
   is called, and that function makes up a "struct net_device" for each port, and
   then calls us here.

   */
static void
plip_init_netdev(struct net_device *dev)
{
	struct net_local *nl = netdev_priv(dev);

	/* Then, override parts of it */
	dev->hard_start_xmit	 = plip_tx_packet;
	dev->open		 = plip_open;
	dev->stop		 = plip_close;
	dev->get_stats 		 = plip_get_stats;
	dev->do_ioctl		 = plip_ioctl;
	dev->header_cache_update = NULL;
	dev->tx_queue_len 	 = 10;
	dev->flags	         = IFF_POINTOPOINT|IFF_NOARP;
	memset(dev->dev_addr, 0xfc, ETH_ALEN);

	/* Set the private structure */
	nl->orig_hard_header    = dev->hard_header;
	dev->hard_header        = plip_hard_header;

	nl->orig_hard_header_cache = dev->hard_header_cache;
	dev->hard_header_cache     = plip_hard_header_cache;


	nl->port_owner = 0;

	/* Initialize constants */
	nl->trigger	= PLIP_TRIGGER_WAIT;
	nl->nibble	= PLIP_NIBBLE_WAIT;

	/* Initialize task queue structures */
	INIT_WORK(&nl->immediate, plip_bh);
	INIT_DELAYED_WORK(&nl->deferred, plip_kick_bh);

	if (dev->irq == -1)
		INIT_DELAYED_WORK(&nl->timer, plip_timer_bh);

	spin_lock_init(&nl->lock);
}

/* Bottom half handler for the delayed request.
   This routine is kicked by do_timer().
   Request `plip_bh' to be invoked. */
static void
plip_kick_bh(struct work_struct *work)
{
	struct net_local *nl =
		container_of(work, struct net_local, deferred.work);

	if (nl->is_deferred)
		schedule_work(&nl->immediate);
}

/* Forward declarations of internal routines */
static int plip_none(struct net_device *, struct net_local *,
		     struct plip_local *, struct plip_local *);
static int plip_receive_packet(struct net_device *, struct net_local *,
			       struct plip_local *, struct plip_local *);
static int plip_send_packet(struct net_device *, struct net_local *,
			    struct plip_local *, struct plip_local *);
static int plip_connection_close(struct net_device *, struct net_local *,
				 struct plip_local *, struct plip_local *);
static int plip_error(struct net_device *, struct net_local *,
		      struct plip_local *, struct plip_local *);
static int plip_bh_timeout_error(struct net_device *dev, struct net_local *nl,
				 struct plip_local *snd,
				 struct plip_local *rcv,
				 int error);

#define OK        0
#define TIMEOUT   1
#define ERROR     2
#define HS_TIMEOUT	3

typedef int (*plip_func)(struct net_device *dev, struct net_local *nl,
			 struct plip_local *snd, struct plip_local *rcv);

static const plip_func connection_state_table[] =
{
	plip_none,
	plip_receive_packet,
	plip_send_packet,
	plip_connection_close,
	plip_error
};

/* Bottom half handler of PLIP. */
static void
plip_bh(struct work_struct *work)
{
	struct net_local *nl = container_of(work, struct net_local, immediate);
	struct plip_local *snd = &nl->snd_data;
	struct plip_local *rcv = &nl->rcv_data;
	plip_func f;
	int r;

	nl->is_deferred = 0;
	f = connection_state_table[nl->connection];
	if ((r = (*f)(nl->dev, nl, snd, rcv)) != OK
	    && (r = plip_bh_timeout_error(nl->dev, nl, snd, rcv, r)) != OK) {
		nl->is_deferred = 1;
		schedule_delayed_work(&nl->deferred, 1);
	}
}

static void
plip_timer_bh(struct work_struct *work)
{
	struct net_local *nl =
		container_of(work, struct net_local, timer.work);

	if (!(atomic_read (&nl->kill_timer))) {
		plip_interrupt (-1, nl->dev);

		schedule_delayed_work(&nl->timer, 1);
	}
	else {
		up (&nl->killed_timer_sem);
	}
}

static int
plip_bh_timeout_error(struct net_device *dev, struct net_local *nl,
		      struct plip_local *snd, struct plip_local *rcv,
		      int error)
{
	unsigned char c0;
	/*
	 * This is tricky. If we got here from the beginning of send (either
	 * with ERROR or HS_TIMEOUT) we have IRQ enabled. Otherwise it's
	 * already disabled. With the old variant of {enable,disable}_irq()
	 * extra disable_irq() was a no-op. Now it became mortal - it's
	 * unbalanced and thus we'll never re-enable IRQ (until rmmod plip,
	 * that is). So we have to treat HS_TIMEOUT and ERROR from send
	 * in a special way.
	 */

	spin_lock_irq(&nl->lock);
	if (nl->connection == PLIP_CN_SEND) {

		if (error != ERROR) { /* Timeout */
			nl->timeout_count++;
			if ((error == HS_TIMEOUT
			     && nl->timeout_count <= 10)
			    || nl->timeout_count <= 3) {
				spin_unlock_irq(&nl->lock);
				/* Try again later */
				return TIMEOUT;
			}
			c0 = read_status(dev);
			printk(KERN_WARNING "%s: transmit timeout(%d,%02x)\n",
			       dev->name, snd->state, c0);
		} else
			error = HS_TIMEOUT;
		nl->enet_stats.tx_errors++;
		nl->enet_stats.tx_aborted_errors++;
	} else if (nl->connection == PLIP_CN_RECEIVE) {
		if (rcv->state == PLIP_PK_TRIGGER) {
			/* Transmission was interrupted. */
			spin_unlock_irq(&nl->lock);
			return OK;
		}
		if (error != ERROR) { /* Timeout */
			if (++nl->timeout_count <= 3) {
				spin_unlock_irq(&nl->lock);
				/* Try again later */
				return TIMEOUT;
			}
			c0 = read_status(dev);
			printk(KERN_WARNING "%s: receive timeout(%d,%02x)\n",
			       dev->name, rcv->state, c0);
		}
		nl->enet_stats.rx_dropped++;
	}
	rcv->state = PLIP_PK_DONE;
	if (rcv->skb) {
		kfree_skb(rcv->skb);
		rcv->skb = NULL;
	}
	snd->state = PLIP_PK_DONE;
	if (snd->skb) {
		dev_kfree_skb(snd->skb);
		snd->skb = NULL;
	}
	spin_unlock_irq(&nl->lock);
	if (error == HS_TIMEOUT) {
		DISABLE(dev->irq);
		synchronize_irq(dev->irq);
	}
	disable_parport_interrupts (dev);
	netif_stop_queue (dev);
	nl->connection = PLIP_CN_ERROR;
	write_data (dev, 0x00);

	return TIMEOUT;
}

static int
plip_none(struct net_device *dev, struct net_local *nl,
	  struct plip_local *snd, struct plip_local *rcv)
{
	return OK;
}

/* PLIP_RECEIVE --- receive a byte(two nibbles)
   Returns OK on success, TIMEOUT on timeout */
static inline int
plip_receive(unsigned short nibble_timeout, struct net_device *dev,
	     enum plip_nibble_state *ns_p, unsigned char *data_p)
{
	unsigned char c0, c1;
	unsigned int cx;

	switch (*ns_p) {
	case PLIP_NB_BEGIN:
		cx = nibble_timeout;
		while (1) {
			c0 = read_status(dev);
			udelay(PLIP_DELAY_UNIT);
			if ((c0 & 0x80) == 0) {
				c1 = read_status(dev);
				if (c0 == c1)
					break;
			}
			if (--cx == 0)
				return TIMEOUT;
		}
		*data_p = (c0 >> 3) & 0x0f;
		write_data (dev, 0x10); /* send ACK */
		*ns_p = PLIP_NB_1;

	case PLIP_NB_1:
		cx = nibble_timeout;
		while (1) {
			c0 = read_status(dev);
			udelay(PLIP_DELAY_UNIT);
			if (c0 & 0x80) {
				c1 = read_status(dev);
				if (c0 == c1)
					break;
			}
			if (--cx == 0)
				return TIMEOUT;
		}
		*data_p |= (c0 << 1) & 0xf0;
		write_data (dev, 0x00); /* send ACK */
		*ns_p = PLIP_NB_BEGIN;
	case PLIP_NB_2:
		break;
	}
	return OK;
}

/*
 *	Determine the packet's protocol ID. The rule here is that we
 *	assume 802.3 if the type field is short enough to be a length.
 *	This is normal practice and works for any 'now in use' protocol.
 *
 *	PLIP is ethernet ish but the daddr might not be valid if unicast.
 *	PLIP fortunately has no bus architecture (its Point-to-point).
 *
 *	We can't fix the daddr thing as that quirk (more bug) is embedded
 *	in far too many old systems not all even running Linux.
 */

static __be16 plip_type_trans(struct sk_buff *skb, struct net_device *dev)
{
	struct ethhdr *eth;
	unsigned char *rawp;

	skb_reset_mac_header(skb);
	skb_pull(skb,dev->hard_header_len);
	eth = eth_hdr(skb);

	if(*eth->h_dest&1)
	{
		if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0)
			skb->pkt_type=PACKET_BROADCAST;
		else
			skb->pkt_type=PACKET_MULTICAST;
	}

	/*
	 *	This ALLMULTI check should be redundant by 1.4
	 *	so don't forget to remove it.
	 */

	if (ntohs(eth->h_proto) >= 1536)
		return eth->h_proto;

	rawp = skb->data;

	/*
	 *	This is a magic hack to spot IPX packets. Older Novell breaks
	 *	the protocol design and runs IPX over 802.3 without an 802.2 LLC
	 *	layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
	 *	won't work for fault tolerant netware but does for the rest.
	 */
	if (*(unsigned short *)rawp == 0xFFFF)
		return htons(ETH_P_802_3);

	/*
	 *	Real 802.2 LLC
	 */
	return htons(ETH_P_802_2);
}

/* PLIP_RECEIVE_PACKET --- receive a packet */
static int
plip_receive_packet(struct net_device *dev, struct net_local *nl,
		    struct plip_local *snd, struct plip_local *rcv)
{
	unsigned short nibble_timeout = nl->nibble;
	unsigned char *lbuf;

	switch (rcv->state) {
	case PLIP_PK_TRIGGER:
		DISABLE(dev->irq);
		/* Don't need to synchronize irq, as we can safely ignore it */
		disable_parport_interrupts (dev);
		write_data (dev, 0x01); /* send ACK */
		if (net_debug > 2)
			printk(KERN_DEBUG "%s: receive start\n", dev->name);
		rcv->state = PLIP_PK_LENGTH_LSB;
		rcv->nibble = PLIP_NB_BEGIN;

	case PLIP_PK_LENGTH_LSB:
		if (snd->state != PLIP_PK_DONE) {
			if (plip_receive(nl->trigger, dev,
					 &rcv->nibble, &rcv->length.b.lsb)) {
				/* collision, here dev->tbusy == 1 */
				rcv->state = PLIP_PK_DONE;
				nl->is_deferred = 1;
				nl->connection = PLIP_CN_SEND;
				schedule_delayed_work(&nl->deferred, 1);
				enable_parport_interrupts (dev);
				ENABLE(dev->irq);
				return OK;
			}
		} else {
			if (plip_receive(nibble_timeout, dev,
					 &rcv->nibble, &rcv->length.b.lsb))
				return TIMEOUT;
		}
		rcv->state = PLIP_PK_LENGTH_MSB;

	case PLIP_PK_LENGTH_MSB:
		if (plip_receive(nibble_timeout, dev,
				 &rcv->nibble, &rcv->length.b.msb))
			return TIMEOUT;
		if (rcv->length.h > dev->mtu + dev->hard_header_len
		    || rcv->length.h < 8) {
			printk(KERN_WARNING "%s: bogus packet size %d.\n", dev->name, rcv->length.h);
			return ERROR;
		}
		/* Malloc up new buffer. */
		rcv->skb = dev_alloc_skb(rcv->length.h + 2);
		if (rcv->skb == NULL) {
			printk(KERN_ERR "%s: Memory squeeze.\n", dev->name);
			return ERROR;
		}
		skb_reserve(rcv->skb, 2);	/* Align IP on 16 byte boundaries */
		skb_put(rcv->skb,rcv->length.h);
		rcv->skb->dev = dev;
		rcv->state = PLIP_PK_DATA;
		rcv->byte = 0;
		rcv->checksum = 0;

	case PLIP_PK_DATA:
		lbuf = rcv->skb->data;
		do
			if (plip_receive(nibble_timeout, dev,
					 &rcv->nibble, &lbuf[rcv->byte]))
				return TIMEOUT;
		while (++rcv->byte < rcv->length.h);
		do
			rcv->checksum += lbuf[--rcv->byte];
		while (rcv->byte);
		rcv->state = PLIP_PK_CHECKSUM;

	case PLIP_PK_CHECKSUM:
		if (plip_receive(nibble_timeout, dev,
				 &rcv->nibble, &rcv->data))
			return TIMEOUT;
		if (rcv->data != rcv->checksum) {
			nl->enet_stats.rx_crc_errors++;
			if (net_debug)
				printk(KERN_DEBUG "%s: checksum error\n", dev->name);
			return ERROR;
		}
		rcv->state = PLIP_PK_DONE;

	case PLIP_PK_DONE:
		/* Inform the upper layer for the arrival of a packet. */
		rcv->skb->protocol=plip_type_trans(rcv->skb, dev);
		netif_rx(rcv->skb);
		dev->last_rx = jiffies;
		nl->enet_stats.rx_bytes += rcv->length.h;
		nl->enet_stats.rx_packets++;
		rcv->skb = NULL;
		if (net_debug > 2)
			printk(KERN_DEBUG "%s: receive end\n", dev->name);

		/* Close the connection. */
		write_data (dev, 0x00);
		spin_lock_irq(&nl->lock);
		if (snd->state != PLIP_PK_DONE) {
			nl->connection = PLIP_CN_SEND;
			spin_unlock_irq(&nl->lock);
			schedule_work(&nl->immediate);
			enable_parport_interrupts (dev);
			ENABLE(dev->irq);
			return OK;
		} else {
			nl->connection = PLIP_CN_NONE;
			spin_unlock_irq(&nl->lock);
			enable_parport_interrupts (dev);
			ENABLE(dev->irq);
			return OK;
		}
	}
	return OK;
}

/* PLIP_SEND --- send a byte (two nibbles)
   Returns OK on success, TIMEOUT when timeout    */
static inline int
plip_send(unsigned short nibble_timeout, struct net_device *dev,
	  enum plip_nibble_state *ns_p, unsigned char data)
{
	unsigned char c0;
	unsigned int cx;

	switch (*ns_p) {
	case PLIP_NB_BEGIN:
		write_data (dev, data & 0x0f);
		*ns_p = PLIP_NB_1;

	case PLIP_NB_1:
		write_data (dev, 0x10 | (data & 0x0f));
		cx = nibble_timeout;
		while (1) {
			c0 = read_status(dev);
			if ((c0 & 0x80) == 0)
				break;
			if (--cx == 0)
				return TIMEOUT;
			udelay(PLIP_DELAY_UNIT);
		}
		write_data (dev, 0x10 | (data >> 4));
		*ns_p = PLIP_NB_2;

	case PLIP_NB_2:
		write_data (dev, (data >> 4));
		cx = nibble_timeout;
		while (1) {
			c0 = read_status(dev);
			if (c0 & 0x80)
				break;
			if (--cx == 0)
				return TIMEOUT;
			udelay(PLIP_DELAY_UNIT);
		}
		*ns_p = PLIP_NB_BEGIN;
		return OK;
	}
	return OK;
}

/* PLIP_SEND_PACKET --- send a packet */
static int
plip_send_packet(struct net_device *dev, struct net_local *nl,
		 struct plip_local *snd, struct plip_local *rcv)
{
	unsigned short nibble_timeout = nl->nibble;
	unsigned char *lbuf;
	unsigned char c0;
	unsigned int cx;

	if (snd->skb == NULL || (lbuf = snd->skb->data) == NULL) {
		printk(KERN_DEBUG "%s: send skb lost\n", dev->name);
		snd->state = PLIP_PK_DONE;
		snd->skb = NULL;
		return ERROR;
	}

	switch (snd->state) {
	case PLIP_PK_TRIGGER:
		if ((read_status(dev) & 0xf8) != 0x80)
			return HS_TIMEOUT;

		/* Trigger remote rx interrupt. */
		write_data (dev, 0x08);
		cx = nl->trigger;
		while (1) {
			udelay(PLIP_DELAY_UNIT);
			spin_lock_irq(&nl->lock);
			if (nl->connection == PLIP_CN_RECEIVE) {
				spin_unlock_irq(&nl->lock);
				/* Interrupted. */
				nl->enet_stats.collisions++;
				return OK;
			}
			c0 = read_status(dev);
			if (c0 & 0x08) {
				spin_unlock_irq(&nl->lock);
				DISABLE(dev->irq);
				synchronize_irq(dev->irq);
				if (nl->connection == PLIP_CN_RECEIVE) {
					/* Interrupted.
					   We don't need to enable irq,
					   as it is soon disabled.    */
					/* Yes, we do. New variant of
					   {enable,disable}_irq *counts*
					   them.  -- AV  */
					ENABLE(dev->irq);
					nl->enet_stats.collisions++;
					return OK;
				}
				disable_parport_interrupts (dev);
				if (net_debug > 2)
					printk(KERN_DEBUG "%s: send start\n", dev->name);
				snd->state = PLIP_PK_LENGTH_LSB;
				snd->nibble = PLIP_NB_BEGIN;
				nl->timeout_count = 0;
				break;
			}
			spin_unlock_irq(&nl->lock);
			if (--cx == 0) {
				write_data (dev, 0x00);
				return HS_TIMEOUT;
			}
		}

	case PLIP_PK_LENGTH_LSB:
		if (plip_send(nibble_timeout, dev,
			      &snd->nibble, snd->length.b.lsb))
			return TIMEOUT;
		snd->state = PLIP_PK_LENGTH_MSB;

	case PLIP_PK_LENGTH_MSB:
		if (plip_send(nibble_timeout, dev,
			      &snd->nibble, snd->length.b.msb))
			return TIMEOUT;
		snd->state = PLIP_PK_DATA;
		snd->byte = 0;
		snd->checksum = 0;

	case PLIP_PK_DATA:
		do
			if (plip_send(nibble_timeout, dev,
				      &snd->nibble, lbuf[snd->byte]))
				return TIMEOUT;
		while (++snd->byte < snd->length.h);
		do
			snd->checksum += lbuf[--snd->byte];
		while (snd->byte);
		snd->state = PLIP_PK_CHECKSUM;

	case PLIP_PK_CHECKSUM:
		if (plip_send(nibble_timeout, dev,
			      &snd->nibble, snd->checksum))
			return TIMEOUT;

		nl->enet_stats.tx_bytes += snd->skb->len;
		dev_kfree_skb(snd->skb);
		nl->enet_stats.tx_packets++;
		snd->state = PLIP_PK_DONE;

	case PLIP_PK_DONE:
		/* Close the connection */
		write_data (dev, 0x00);
		snd->skb = NULL;
		if (net_debug > 2)
			printk(KERN_DEBUG "%s: send end\n", dev->name);
		nl->connection = PLIP_CN_CLOSING;
		nl->is_deferred = 1;
		schedule_delayed_work(&nl->deferred, 1);
		enable_parport_interrupts (dev);
		ENABLE(dev->irq);
		return OK;
	}
	return OK;
}

static int
plip_connection_close(struct net_device *dev, struct net_local *nl,
		      struct plip_local *snd, struct plip_local *rcv)
{
	spin_lock_irq(&nl->lock);
	if (nl->connection == PLIP_CN_CLOSING) {
		nl->connection = PLIP_CN_NONE;
		netif_wake_queue (dev);
	}
	spin_unlock_irq(&nl->lock);
	if (nl->should_relinquish) {
		nl->should_relinquish = nl->port_owner = 0;
		parport_release(nl->pardev);
	}
	return OK;
}

/* PLIP_ERROR --- wait till other end settled */
static int
plip_error(struct net_device *dev, struct net_local *nl,
	   struct plip_local *snd, struct plip_local *rcv)
{
	unsigned char status;

	status = read_status(dev);
	if ((status & 0xf8) == 0x80) {
		if (net_debug > 2)
			printk(KERN_DEBUG "%s: reset interface.\n", dev->name);
		nl->connection = PLIP_CN_NONE;
		nl->should_relinquish = 0;
		netif_start_queue (dev);
		enable_parport_interrupts (dev);
		ENABLE(dev->irq);
		netif_wake_queue (dev);
	} else {
		nl->is_deferred = 1;
		schedule_delayed_work(&nl->deferred, 1);
	}

	return OK;
}

/* Handle the parallel port interrupts. */
static void
plip_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct net_local *nl;
	struct plip_local *rcv;
	unsigned char c0;

	nl = netdev_priv(dev);
	rcv = &nl->rcv_data;

	spin_lock_irq (&nl->lock);

	c0 = read_status(dev);
	if ((c0 & 0xf8) != 0xc0) {
		if ((dev->irq != -1) && (net_debug > 1))
			printk(KERN_DEBUG "%s: spurious interrupt\n", dev->name);
		spin_unlock_irq (&nl->lock);
		return;
	}

	if (net_debug > 3)
		printk(KERN_DEBUG "%s: interrupt.\n", dev->name);

	switch (nl->connection) {
	case PLIP_CN_CLOSING:
		netif_wake_queue (dev);
	case PLIP_CN_NONE:
	case PLIP_CN_SEND:
		rcv->state = PLIP_PK_TRIGGER;
		nl->connection = PLIP_CN_RECEIVE;
		nl->timeout_count = 0;
		schedule_work(&nl->immediate);
		break;

	case PLIP_CN_RECEIVE:
		/* May occur because there is race condition
		   around test and set of dev->interrupt.
		   Ignore this interrupt. */
		break;

	case PLIP_CN_ERROR:
		printk(KERN_ERR "%s: receive interrupt in error state\n", dev->name);
		break;
	}

	spin_unlock_irq(&nl->lock);
}

static int
plip_tx_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct net_local *nl = netdev_priv(dev);
	struct plip_local *snd = &nl->snd_data;

	if (netif_queue_stopped(dev))
		return 1;

	/* We may need to grab the bus */
	if (!nl->port_owner) {
		if (parport_claim(nl->pardev))
			return 1;
		nl->port_owner = 1;
	}

	netif_stop_queue (dev);

	if (skb->len > dev->mtu + dev->hard_header_len) {
		printk(KERN_WARNING "%s: packet too big, %d.\n", dev->name, (int)skb->len);
		netif_start_queue (dev);
		return 1;
	}

	if (net_debug > 2)
		printk(KERN_DEBUG "%s: send request\n", dev->name);

	spin_lock_irq(&nl->lock);
	dev->trans_start = jiffies;
	snd->skb = skb;
	snd->length.h = skb->len;
	snd->state = PLIP_PK_TRIGGER;
	if (nl->connection == PLIP_CN_NONE) {
		nl->connection = PLIP_CN_SEND;
		nl->timeout_count = 0;
	}
	schedule_work(&nl->immediate);
	spin_unlock_irq(&nl->lock);

	return 0;
}

static void
plip_rewrite_address(struct net_device *dev, struct ethhdr *eth)
{
	struct in_device *in_dev;

	if ((in_dev=dev->ip_ptr) != NULL) {
		/* Any address will do - we take the first */
		struct in_ifaddr *ifa=in_dev->ifa_list;
		if (ifa != NULL) {
			memcpy(eth->h_source, dev->dev_addr, 6);
			memset(eth->h_dest, 0xfc, 2);
			memcpy(eth->h_dest+2, &ifa->ifa_address, 4);
		}
	}
}

static int
plip_hard_header(struct sk_buff *skb, struct net_device *dev,
                 unsigned short type, void *daddr,
	         void *saddr, unsigned len)
{
	struct net_local *nl = netdev_priv(dev);
	int ret;

	if ((ret = nl->orig_hard_header(skb, dev, type, daddr, saddr, len)) >= 0)
		plip_rewrite_address (dev, (struct ethhdr *)skb->data);

	return ret;
}

int plip_hard_header_cache(struct neighbour *neigh,
                           struct hh_cache *hh)
{
	struct net_local *nl = neigh->dev->priv;
	int ret;

	if ((ret = nl->orig_hard_header_cache(neigh, hh)) == 0)
	{
		struct ethhdr *eth;

		eth = (struct ethhdr*)(((u8*)hh->hh_data) +
				       HH_DATA_OFF(sizeof(*eth)));
		plip_rewrite_address (neigh->dev, eth);
	}

	return ret;
}

/* Open/initialize the board.  This is called (in the current kernel)
   sometime after booting when the 'ifconfig' program is run.

   This routine gets exclusive access to the parallel port by allocating
   its IRQ line.
 */
static int
plip_open(struct net_device *dev)
{
	struct net_local *nl = netdev_priv(dev);
	struct in_device *in_dev;

	/* Grab the port */
	if (!nl->port_owner) {
		if (parport_claim(nl->pardev)) return -EAGAIN;
		nl->port_owner = 1;
	}

	nl->should_relinquish = 0;

	/* Clear the data port. */
	write_data (dev, 0x00);

	/* Enable rx interrupt. */
	enable_parport_interrupts (dev);
	if (dev->irq == -1)
	{
		atomic_set (&nl->kill_timer, 0);
		schedule_delayed_work(&nl->timer, 1);
	}

	/* Initialize the state machine. */
	nl->rcv_data.state = nl->snd_data.state = PLIP_PK_DONE;
	nl->rcv_data.skb = nl->snd_data.skb = NULL;
	nl->connection = PLIP_CN_NONE;
	nl->is_deferred = 0;

	/* Fill in the MAC-level header.
	   We used to abuse dev->broadcast to store the point-to-point
	   MAC address, but we no longer do it. Instead, we fetch the
	   interface address whenever it is needed, which is cheap enough
	   because we use the hh_cache. Actually, abusing dev->broadcast
	   didn't work, because when using plip_open the point-to-point
	   address isn't yet known.
	   PLIP doesn't have a real MAC address, but we need it to be
	   DOS compatible, and to properly support taps (otherwise,
	   when the device address isn't identical to the address of a
	   received frame, the kernel incorrectly drops it).             */

	if ((in_dev=dev->ip_ptr) != NULL) {
		/* Any address will do - we take the first. We already
		   have the first two bytes filled with 0xfc, from
		   plip_init_dev(). */
		struct in_ifaddr *ifa=in_dev->ifa_list;
		if (ifa != NULL) {
			memcpy(dev->dev_addr+2, &ifa->ifa_local, 4);
		}
	}

	netif_start_queue (dev);

	return 0;
}

/* The inverse routine to plip_open (). */
static int
plip_close(struct net_device *dev)
{
	struct net_local *nl = netdev_priv(dev);
	struct plip_local *snd = &nl->snd_data;
	struct plip_local *rcv = &nl->rcv_data;

	netif_stop_queue (dev);
	DISABLE(dev->irq);
	synchronize_irq(dev->irq);

	if (dev->irq == -1)
	{
		init_MUTEX_LOCKED (&nl->killed_timer_sem);
		atomic_set (&nl->kill_timer, 1);
		down (&nl->killed_timer_sem);
	}

#ifdef NOTDEF
	outb(0x00, PAR_DATA(dev));
#endif
	nl->is_deferred = 0;
	nl->connection = PLIP_CN_NONE;
	if (nl->port_owner) {
		parport_release(nl->pardev);
		nl->port_owner = 0;
	}

	snd->state = PLIP_PK_DONE;
	if (snd->skb) {
		dev_kfree_skb(snd->skb);
		snd->skb = NULL;
	}
	rcv->state = PLIP_PK_DONE;
	if (rcv->skb) {
		kfree_skb(rcv->skb);
		rcv->skb = NULL;
	}

#ifdef NOTDEF
	/* Reset. */
	outb(0x00, PAR_CONTROL(dev));
#endif
	return 0;
}

static int
plip_preempt(void *handle)
{
	struct net_device *dev = (struct net_device *)handle;
	struct net_local *nl = netdev_priv(dev);

	/* Stand our ground if a datagram is on the wire */
	if (nl->connection != PLIP_CN_NONE) {
		nl->should_relinquish = 1;
		return 1;
	}

	nl->port_owner = 0;	/* Remember that we released the bus */
	return 0;
}

static void
plip_wakeup(void *handle)
{
	struct net_device *dev = (struct net_device *)handle;
	struct net_local *nl = netdev_priv(dev);

	if (nl->port_owner) {
		/* Why are we being woken up? */
		printk(KERN_DEBUG "%s: why am I being woken up?\n", dev->name);
		if (!parport_claim(nl->pardev))
			/* bus_owner is already set (but why?) */
			printk(KERN_DEBUG "%s: I'm broken.\n", dev->name);
		else
			return;
	}

	if (!(dev->flags & IFF_UP))
		/* Don't need the port when the interface is down */
		return;

	if (!parport_claim(nl->pardev)) {
		nl->port_owner = 1;
		/* Clear the data port. */
		write_data (dev, 0x00);
	}

	return;
}

static struct net_device_stats *
plip_get_stats(struct net_device *dev)
{
	struct net_local *nl = netdev_priv(dev);
	struct net_device_stats *r = &nl->enet_stats;

	return r;
}

static int
plip_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	struct net_local *nl = netdev_priv(dev);
	struct plipconf *pc = (struct plipconf *) &rq->ifr_ifru;

	if (cmd != SIOCDEVPLIP)
		return -EOPNOTSUPP;

	switch(pc->pcmd) {
	case PLIP_GET_TIMEOUT:
		pc->trigger = nl->trigger;
		pc->nibble  = nl->nibble;
		break;
	case PLIP_SET_TIMEOUT:
		if(!capable(CAP_NET_ADMIN))
			return -EPERM;
		nl->trigger = pc->trigger;
		nl->nibble  = pc->nibble;
		break;
	default:
		return -EOPNOTSUPP;
	}
	return 0;
}

static int parport[PLIP_MAX] = { [0 ... PLIP_MAX-1] = -1 };
static int timid;

module_param_array(parport, int, NULL, 0);
module_param(timid, int, 0);
MODULE_PARM_DESC(parport, "List of parport device numbers to use by plip");

static struct net_device *dev_plip[PLIP_MAX] = { NULL, };

static inline int
plip_searchfor(int list[], int a)
{
	int i;
	for (i = 0; i < PLIP_MAX && list[i] != -1; i++) {
		if (list[i] == a) return 1;
	}
	return 0;
}

/* plip_attach() is called (by the parport code) when a port is
 * available to use. */
static void plip_attach (struct parport *port)
{
	static int unit;
	struct net_device *dev;
	struct net_local *nl;
	char name[IFNAMSIZ];

	if ((parport[0] == -1 && (!timid || !port->devices)) ||
	    plip_searchfor(parport, port->number)) {
		if (unit == PLIP_MAX) {
			printk(KERN_ERR "plip: too many devices\n");
			return;
		}

		sprintf(name, "plip%d", unit);
		dev = alloc_etherdev(sizeof(struct net_local));
		if (!dev) {
			printk(KERN_ERR "plip: memory squeeze\n");
			return;
		}

		strcpy(dev->name, name);

		dev->irq = port->irq;
		dev->base_addr = port->base;
		if (port->irq == -1) {
			printk(KERN_INFO "plip: %s has no IRQ. Using IRQ-less mode,"
		                 "which is fairly inefficient!\n", port->name);
		}

		nl = netdev_priv(dev);
		nl->dev = dev;
		nl->pardev = parport_register_device(port, name, plip_preempt,
						 plip_wakeup, plip_interrupt,
						 0, dev);

		if (!nl->pardev) {
			printk(KERN_ERR "%s: parport_register failed\n", name);
			goto err_free_dev;
			return;
		}

		plip_init_netdev(dev);

		if (register_netdev(dev)) {
			printk(KERN_ERR "%s: network register failed\n", name);
			goto err_parport_unregister;
		}

		printk(KERN_INFO "%s", version);
		if (dev->irq != -1)
			printk(KERN_INFO "%s: Parallel port at %#3lx, "
					 "using IRQ %d.\n",
				         dev->name, dev->base_addr, dev->irq);
		else
			printk(KERN_INFO "%s: Parallel port at %#3lx, "
					 "not using IRQ.\n",
					 dev->name, dev->base_addr);
		dev_plip[unit++] = dev;
	}
	return;

err_parport_unregister:
	parport_unregister_device(nl->pardev);
err_free_dev:
	free_netdev(dev);
	return;
}

/* plip_detach() is called (by the parport code) when a port is
 * no longer available to use. */
static void plip_detach (struct parport *port)
{
	/* Nothing to do */
}

static struct parport_driver plip_driver = {
	.name	= "plip",
	.attach = plip_attach,
	.detach = plip_detach
};

static void __exit plip_cleanup_module (void)
{
	struct net_device *dev;
	int i;

	parport_unregister_driver (&plip_driver);

	for (i=0; i < PLIP_MAX; i++) {
		if ((dev = dev_plip[i])) {
			struct net_local *nl = netdev_priv(dev);
			unregister_netdev(dev);
			if (nl->port_owner)
				parport_release(nl->pardev);
			parport_unregister_device(nl->pardev);
			free_netdev(dev);
			dev_plip[i] = NULL;
		}
	}
}

#ifndef MODULE

static int parport_ptr;

static int __init plip_setup(char *str)
{
	int ints[4];

	str = get_options(str, ARRAY_SIZE(ints), ints);

	/* Ugh. */
	if (!strncmp(str, "parport", 7)) {
		int n = simple_strtoul(str+7, NULL, 10);
		if (parport_ptr < PLIP_MAX)
			parport[parport_ptr++] = n;
		else
			printk(KERN_INFO "plip: too many ports, %s ignored.\n",
			       str);
	} else if (!strcmp(str, "timid")) {
		timid = 1;
	} else {
		if (ints[0] == 0 || ints[1] == 0) {
			/* disable driver on "plip=" or "plip=0" */
			parport[0] = -2;
		} else {
			printk(KERN_WARNING "warning: 'plip=0x%x' ignored\n",
			       ints[1]);
		}
	}
	return 1;
}

__setup("plip=", plip_setup);

#endif /* !MODULE */

static int __init plip_init (void)
{
	if (parport[0] == -2)
		return 0;

	if (parport[0] != -1 && timid) {
		printk(KERN_WARNING "plip: warning, ignoring `timid' since specific ports given.\n");
		timid = 0;
	}

	if (parport_register_driver (&plip_driver)) {
		printk (KERN_WARNING "plip: couldn't register driver\n");
		return 1;
	}

	return 0;
}

module_init(plip_init);
module_exit(plip_cleanup_module);
MODULE_LICENSE("GPL");

/*
 * Local variables:
 * compile-command: "gcc -DMODULE -DMODVERSIONS -D__KERNEL__ -Wall -Wstrict-prototypes -O2 -g -fomit-frame-pointer -pipe -c plip.c"
 * End:
 */