summaryrefslogtreecommitdiff
path: root/drivers/net/enc28j60.c
blob: d186a52cdb62831000286e7e7d3fd111f0b5f875 (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
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
/*
 * Microchip ENC28J60 ethernet driver (MAC + PHY)
 *
 * Copyright (C) 2007 Eurek srl
 * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
 * based on enc28j60.c written by David Anders for 2.4 kernel version
 *
 * 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.
 *
 * $Id: enc28j60.c,v 1.22 2007/12/20 10:47:01 claudio Exp $
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/tcp.h>
#include <linux/skbuff.h>
#include <linux/delay.h>
#include <linux/spi/spi.h>

#include "enc28j60_hw.h"

#define DRV_NAME	"enc28j60"
#define DRV_VERSION	"1.01"

#define SPI_OPLEN	1

#define ENC28J60_MSG_DEFAULT	\
	(NETIF_MSG_PROBE | NETIF_MSG_IFUP | NETIF_MSG_IFDOWN | NETIF_MSG_LINK)

/* Buffer size required for the largest SPI transfer (i.e., reading a
 * frame). */
#define SPI_TRANSFER_BUF_LEN	(4 + MAX_FRAMELEN)

#define TX_TIMEOUT	(4 * HZ)

/* Max TX retries in case of collision as suggested by errata datasheet */
#define MAX_TX_RETRYCOUNT	16

enum {
	RXFILTER_NORMAL,
	RXFILTER_MULTI,
	RXFILTER_PROMISC
};

/* Driver local data */
struct enc28j60_net {
	struct net_device *netdev;
	struct spi_device *spi;
	struct mutex lock;
	struct sk_buff *tx_skb;
	struct work_struct tx_work;
	struct work_struct irq_work;
	struct work_struct setrx_work;
	struct work_struct restart_work;
	u8 bank;		/* current register bank selected */
	u16 next_pk_ptr;	/* next packet pointer within FIFO */
	u16 max_pk_counter;	/* statistics: max packet counter */
	u16 tx_retry_count;
	bool hw_enable;
	bool full_duplex;
	int rxfilter;
	u32 msg_enable;
	u8 spi_transfer_buf[SPI_TRANSFER_BUF_LEN];
};

/* use ethtool to change the level for any given device */
static struct {
	u32 msg_enable;
} debug = { -1 };

/*
 * SPI read buffer
 * wait for the SPI transfer and copy received data to destination
 */
static int
spi_read_buf(struct enc28j60_net *priv, int len, u8 *data)
{
	u8 *rx_buf = priv->spi_transfer_buf + 4;
	u8 *tx_buf = priv->spi_transfer_buf;
	struct spi_transfer t = {
		.tx_buf = tx_buf,
		.rx_buf = rx_buf,
		.len = SPI_OPLEN + len,
	};
	struct spi_message msg;
	int ret;

	tx_buf[0] = ENC28J60_READ_BUF_MEM;
	tx_buf[1] = tx_buf[2] = tx_buf[3] = 0;	/* don't care */

	spi_message_init(&msg);
	spi_message_add_tail(&t, &msg);
	ret = spi_sync(priv->spi, &msg);
	if (ret == 0) {
		memcpy(data, &rx_buf[SPI_OPLEN], len);
		ret = msg.status;
	}
	if (ret && netif_msg_drv(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() failed: ret = %d\n",
			__func__, ret);

	return ret;
}

/*
 * SPI write buffer
 */
static int spi_write_buf(struct enc28j60_net *priv, int len,
			 const u8 *data)
{
	int ret;

	if (len > SPI_TRANSFER_BUF_LEN - 1 || len <= 0)
		ret = -EINVAL;
	else {
		priv->spi_transfer_buf[0] = ENC28J60_WRITE_BUF_MEM;
		memcpy(&priv->spi_transfer_buf[1], data, len);
		ret = spi_write(priv->spi, priv->spi_transfer_buf, len + 1);
		if (ret && netif_msg_drv(priv))
			printk(KERN_DEBUG DRV_NAME ": %s() failed: ret = %d\n",
				__func__, ret);
	}
	return ret;
}

/*
 * basic SPI read operation
 */
static u8 spi_read_op(struct enc28j60_net *priv, u8 op,
			   u8 addr)
{
	u8 tx_buf[2];
	u8 rx_buf[4];
	u8 val = 0;
	int ret;
	int slen = SPI_OPLEN;

	/* do dummy read if needed */
	if (addr & SPRD_MASK)
		slen++;

	tx_buf[0] = op | (addr & ADDR_MASK);
	ret = spi_write_then_read(priv->spi, tx_buf, 1, rx_buf, slen);
	if (ret)
		printk(KERN_DEBUG DRV_NAME ": %s() failed: ret = %d\n",
			__func__, ret);
	else
		val = rx_buf[slen - 1];

	return val;
}

/*
 * basic SPI write operation
 */
static int spi_write_op(struct enc28j60_net *priv, u8 op,
			u8 addr, u8 val)
{
	int ret;

	priv->spi_transfer_buf[0] = op | (addr & ADDR_MASK);
	priv->spi_transfer_buf[1] = val;
	ret = spi_write(priv->spi, priv->spi_transfer_buf, 2);
	if (ret && netif_msg_drv(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() failed: ret = %d\n",
			__func__, ret);
	return ret;
}

static void enc28j60_soft_reset(struct enc28j60_net *priv)
{
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() enter\n", __func__);

	spi_write_op(priv, ENC28J60_SOFT_RESET, 0, ENC28J60_SOFT_RESET);
	/* Errata workaround #1, CLKRDY check is unreliable,
	 * delay at least 1 mS instead */
	udelay(2000);
}

/*
 * select the current register bank if necessary
 */
static void enc28j60_set_bank(struct enc28j60_net *priv, u8 addr)
{
	if ((addr & BANK_MASK) != priv->bank) {
		u8 b = (addr & BANK_MASK) >> 5;

		if (b != (ECON1_BSEL1 | ECON1_BSEL0))
			spi_write_op(priv, ENC28J60_BIT_FIELD_CLR, ECON1,
				     ECON1_BSEL1 | ECON1_BSEL0);
		if (b != 0)
			spi_write_op(priv, ENC28J60_BIT_FIELD_SET, ECON1, b);
		priv->bank = (addr & BANK_MASK);
	}
}

/*
 * Register access routines through the SPI bus.
 * Every register access comes in two flavours:
 * - nolock_xxx: caller needs to invoke mutex_lock, usually to access
 *   atomically more than one register
 * - locked_xxx: caller doesn't need to invoke mutex_lock, single access
 *
 * Some registers can be accessed through the bit field clear and
 * bit field set to avoid a read modify write cycle.
 */

/*
 * Register bit field Set
 */
static void nolock_reg_bfset(struct enc28j60_net *priv,
				      u8 addr, u8 mask)
{
	enc28j60_set_bank(priv, addr);
	spi_write_op(priv, ENC28J60_BIT_FIELD_SET, addr, mask);
}

static void locked_reg_bfset(struct enc28j60_net *priv,
				      u8 addr, u8 mask)
{
	mutex_lock(&priv->lock);
	nolock_reg_bfset(priv, addr, mask);
	mutex_unlock(&priv->lock);
}

/*
 * Register bit field Clear
 */
static void nolock_reg_bfclr(struct enc28j60_net *priv,
				      u8 addr, u8 mask)
{
	enc28j60_set_bank(priv, addr);
	spi_write_op(priv, ENC28J60_BIT_FIELD_CLR, addr, mask);
}

static void locked_reg_bfclr(struct enc28j60_net *priv,
				      u8 addr, u8 mask)
{
	mutex_lock(&priv->lock);
	nolock_reg_bfclr(priv, addr, mask);
	mutex_unlock(&priv->lock);
}

/*
 * Register byte read
 */
static int nolock_regb_read(struct enc28j60_net *priv,
				     u8 address)
{
	enc28j60_set_bank(priv, address);
	return spi_read_op(priv, ENC28J60_READ_CTRL_REG, address);
}

static int locked_regb_read(struct enc28j60_net *priv,
				     u8 address)
{
	int ret;

	mutex_lock(&priv->lock);
	ret = nolock_regb_read(priv, address);
	mutex_unlock(&priv->lock);

	return ret;
}

/*
 * Register word read
 */
static int nolock_regw_read(struct enc28j60_net *priv,
				     u8 address)
{
	int rl, rh;

	enc28j60_set_bank(priv, address);
	rl = spi_read_op(priv, ENC28J60_READ_CTRL_REG, address);
	rh = spi_read_op(priv, ENC28J60_READ_CTRL_REG, address + 1);

	return (rh << 8) | rl;
}

static int locked_regw_read(struct enc28j60_net *priv,
				     u8 address)
{
	int ret;

	mutex_lock(&priv->lock);
	ret = nolock_regw_read(priv, address);
	mutex_unlock(&priv->lock);

	return ret;
}

/*
 * Register byte write
 */
static void nolock_regb_write(struct enc28j60_net *priv,
				       u8 address, u8 data)
{
	enc28j60_set_bank(priv, address);
	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, address, data);
}

static void locked_regb_write(struct enc28j60_net *priv,
				       u8 address, u8 data)
{
	mutex_lock(&priv->lock);
	nolock_regb_write(priv, address, data);
	mutex_unlock(&priv->lock);
}

/*
 * Register word write
 */
static void nolock_regw_write(struct enc28j60_net *priv,
				       u8 address, u16 data)
{
	enc28j60_set_bank(priv, address);
	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, address, (u8) data);
	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, address + 1,
		     (u8) (data >> 8));
}

static void locked_regw_write(struct enc28j60_net *priv,
				       u8 address, u16 data)
{
	mutex_lock(&priv->lock);
	nolock_regw_write(priv, address, data);
	mutex_unlock(&priv->lock);
}

/*
 * Buffer memory read
 * Select the starting address and execute a SPI buffer read
 */
static void enc28j60_mem_read(struct enc28j60_net *priv,
				     u16 addr, int len, u8 *data)
{
	mutex_lock(&priv->lock);
	nolock_regw_write(priv, ERDPTL, addr);
#ifdef CONFIG_ENC28J60_WRITEVERIFY
	if (netif_msg_drv(priv)) {
		u16 reg;
		reg = nolock_regw_read(priv, ERDPTL);
		if (reg != addr)
			printk(KERN_DEBUG DRV_NAME ": %s() error writing ERDPT "
				"(0x%04x - 0x%04x)\n", __func__, reg, addr);
	}
#endif
	spi_read_buf(priv, len, data);
	mutex_unlock(&priv->lock);
}

/*
 * Write packet to enc28j60 TX buffer memory
 */
static void
enc28j60_packet_write(struct enc28j60_net *priv, int len, const u8 *data)
{
	mutex_lock(&priv->lock);
	/* Set the write pointer to start of transmit buffer area */
	nolock_regw_write(priv, EWRPTL, TXSTART_INIT);
#ifdef CONFIG_ENC28J60_WRITEVERIFY
	if (netif_msg_drv(priv)) {
		u16 reg;
		reg = nolock_regw_read(priv, EWRPTL);
		if (reg != TXSTART_INIT)
			printk(KERN_DEBUG DRV_NAME
				": %s() ERWPT:0x%04x != 0x%04x\n",
				__func__, reg, TXSTART_INIT);
	}
#endif
	/* Set the TXND pointer to correspond to the packet size given */
	nolock_regw_write(priv, ETXNDL, TXSTART_INIT + len);
	/* write per-packet control byte */
	spi_write_op(priv, ENC28J60_WRITE_BUF_MEM, 0, 0x00);
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME
			": %s() after control byte ERWPT:0x%04x\n",
			__func__, nolock_regw_read(priv, EWRPTL));
	/* copy the packet into the transmit buffer */
	spi_write_buf(priv, len, data);
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME
			 ": %s() after write packet ERWPT:0x%04x, len=%d\n",
			 __func__, nolock_regw_read(priv, EWRPTL), len);
	mutex_unlock(&priv->lock);
}

static unsigned long msec20_to_jiffies;

static int poll_ready(struct enc28j60_net *priv, u8 reg, u8 mask, u8 val)
{
	unsigned long timeout = jiffies + msec20_to_jiffies;

	/* 20 msec timeout read */
	while ((nolock_regb_read(priv, reg) & mask) != val) {
		if (time_after(jiffies, timeout)) {
			if (netif_msg_drv(priv))
				dev_dbg(&priv->spi->dev,
					"reg %02x ready timeout!\n", reg);
			return -ETIMEDOUT;
		}
		cpu_relax();
	}
	return 0;
}

/*
 * Wait until the PHY operation is complete.
 */
static int wait_phy_ready(struct enc28j60_net *priv)
{
	return poll_ready(priv, MISTAT, MISTAT_BUSY, 0) ? 0 : 1;
}

/*
 * PHY register read
 * PHY registers are not accessed directly, but through the MII
 */
static u16 enc28j60_phy_read(struct enc28j60_net *priv, u8 address)
{
	u16 ret;

	mutex_lock(&priv->lock);
	/* set the PHY register address */
	nolock_regb_write(priv, MIREGADR, address);
	/* start the register read operation */
	nolock_regb_write(priv, MICMD, MICMD_MIIRD);
	/* wait until the PHY read completes */
	wait_phy_ready(priv);
	/* quit reading */
	nolock_regb_write(priv, MICMD, 0x00);
	/* return the data */
	ret  = nolock_regw_read(priv, MIRDL);
	mutex_unlock(&priv->lock);

	return ret;
}

static int enc28j60_phy_write(struct enc28j60_net *priv, u8 address, u16 data)
{
	int ret;

	mutex_lock(&priv->lock);
	/* set the PHY register address */
	nolock_regb_write(priv, MIREGADR, address);
	/* write the PHY data */
	nolock_regw_write(priv, MIWRL, data);
	/* wait until the PHY write completes and return */
	ret = wait_phy_ready(priv);
	mutex_unlock(&priv->lock);

	return ret;
}

/*
 * Program the hardware MAC address from dev->dev_addr.
 */
static int enc28j60_set_hw_macaddr(struct net_device *ndev)
{
	int ret;
	struct enc28j60_net *priv = netdev_priv(ndev);

	mutex_lock(&priv->lock);
	if (!priv->hw_enable) {
		if (netif_msg_drv(priv))
			printk(KERN_INFO DRV_NAME
				": %s: Setting MAC address to %pM\n",
				ndev->name, ndev->dev_addr);
		/* NOTE: MAC address in ENC28J60 is byte-backward */
		nolock_regb_write(priv, MAADR5, ndev->dev_addr[0]);
		nolock_regb_write(priv, MAADR4, ndev->dev_addr[1]);
		nolock_regb_write(priv, MAADR3, ndev->dev_addr[2]);
		nolock_regb_write(priv, MAADR2, ndev->dev_addr[3]);
		nolock_regb_write(priv, MAADR1, ndev->dev_addr[4]);
		nolock_regb_write(priv, MAADR0, ndev->dev_addr[5]);
		ret = 0;
	} else {
		if (netif_msg_drv(priv))
			printk(KERN_DEBUG DRV_NAME
				": %s() Hardware must be disabled to set "
				"Mac address\n", __func__);
		ret = -EBUSY;
	}
	mutex_unlock(&priv->lock);
	return ret;
}

/*
 * Store the new hardware address in dev->dev_addr, and update the MAC.
 */
static int enc28j60_set_mac_address(struct net_device *dev, void *addr)
{
	struct sockaddr *address = addr;

	if (netif_running(dev))
		return -EBUSY;
	if (!is_valid_ether_addr(address->sa_data))
		return -EADDRNOTAVAIL;

	memcpy(dev->dev_addr, address->sa_data, dev->addr_len);
	return enc28j60_set_hw_macaddr(dev);
}

/*
 * Debug routine to dump useful register contents
 */
static void enc28j60_dump_regs(struct enc28j60_net *priv, const char *msg)
{
	mutex_lock(&priv->lock);
	printk(KERN_DEBUG DRV_NAME " %s\n"
		"HwRevID: 0x%02x\n"
		"Cntrl: ECON1 ECON2 ESTAT  EIR  EIE\n"
		"       0x%02x  0x%02x  0x%02x  0x%02x  0x%02x\n"
		"MAC  : MACON1 MACON3 MACON4\n"
		"       0x%02x   0x%02x   0x%02x\n"
		"Rx   : ERXST  ERXND  ERXWRPT ERXRDPT ERXFCON EPKTCNT MAMXFL\n"
		"       0x%04x 0x%04x 0x%04x  0x%04x  "
		"0x%02x    0x%02x    0x%04x\n"
		"Tx   : ETXST  ETXND  MACLCON1 MACLCON2 MAPHSUP\n"
		"       0x%04x 0x%04x 0x%02x     0x%02x     0x%02x\n",
		msg, nolock_regb_read(priv, EREVID),
		nolock_regb_read(priv, ECON1), nolock_regb_read(priv, ECON2),
		nolock_regb_read(priv, ESTAT), nolock_regb_read(priv, EIR),
		nolock_regb_read(priv, EIE), nolock_regb_read(priv, MACON1),
		nolock_regb_read(priv, MACON3), nolock_regb_read(priv, MACON4),
		nolock_regw_read(priv, ERXSTL), nolock_regw_read(priv, ERXNDL),
		nolock_regw_read(priv, ERXWRPTL),
		nolock_regw_read(priv, ERXRDPTL),
		nolock_regb_read(priv, ERXFCON),
		nolock_regb_read(priv, EPKTCNT),
		nolock_regw_read(priv, MAMXFLL), nolock_regw_read(priv, ETXSTL),
		nolock_regw_read(priv, ETXNDL),
		nolock_regb_read(priv, MACLCON1),
		nolock_regb_read(priv, MACLCON2),
		nolock_regb_read(priv, MAPHSUP));
	mutex_unlock(&priv->lock);
}

/*
 * ERXRDPT need to be set always at odd addresses, refer to errata datasheet
 */
static u16 erxrdpt_workaround(u16 next_packet_ptr, u16 start, u16 end)
{
	u16 erxrdpt;

	if ((next_packet_ptr - 1 < start) || (next_packet_ptr - 1 > end))
		erxrdpt = end;
	else
		erxrdpt = next_packet_ptr - 1;

	return erxrdpt;
}

static void nolock_rxfifo_init(struct enc28j60_net *priv, u16 start, u16 end)
{
	u16 erxrdpt;

	if (start > 0x1FFF || end > 0x1FFF || start > end) {
		if (netif_msg_drv(priv))
			printk(KERN_ERR DRV_NAME ": %s(%d, %d) RXFIFO "
				"bad parameters!\n", __func__, start, end);
		return;
	}
	/* set receive buffer start + end */
	priv->next_pk_ptr = start;
	nolock_regw_write(priv, ERXSTL, start);
	erxrdpt = erxrdpt_workaround(priv->next_pk_ptr, start, end);
	nolock_regw_write(priv, ERXRDPTL, erxrdpt);
	nolock_regw_write(priv, ERXNDL, end);
}

static void nolock_txfifo_init(struct enc28j60_net *priv, u16 start, u16 end)
{
	if (start > 0x1FFF || end > 0x1FFF || start > end) {
		if (netif_msg_drv(priv))
			printk(KERN_ERR DRV_NAME ": %s(%d, %d) TXFIFO "
				"bad parameters!\n", __func__, start, end);
		return;
	}
	/* set transmit buffer start + end */
	nolock_regw_write(priv, ETXSTL, start);
	nolock_regw_write(priv, ETXNDL, end);
}

/*
 * Low power mode shrinks power consumption about 100x, so we'd like
 * the chip to be in that mode whenever it's inactive.  (However, we
 * can't stay in lowpower mode during suspend with WOL active.)
 */
static void enc28j60_lowpower(struct enc28j60_net *priv, bool is_low)
{
	if (netif_msg_drv(priv))
		dev_dbg(&priv->spi->dev, "%s power...\n",
				is_low ? "low" : "high");

	mutex_lock(&priv->lock);
	if (is_low) {
		nolock_reg_bfclr(priv, ECON1, ECON1_RXEN);
		poll_ready(priv, ESTAT, ESTAT_RXBUSY, 0);
		poll_ready(priv, ECON1, ECON1_TXRTS, 0);
		/* ECON2_VRPS was set during initialization */
		nolock_reg_bfset(priv, ECON2, ECON2_PWRSV);
	} else {
		nolock_reg_bfclr(priv, ECON2, ECON2_PWRSV);
		poll_ready(priv, ESTAT, ESTAT_CLKRDY, ESTAT_CLKRDY);
		/* caller sets ECON1_RXEN */
	}
	mutex_unlock(&priv->lock);
}

static int enc28j60_hw_init(struct enc28j60_net *priv)
{
	u8 reg;

	if (netif_msg_drv(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() - %s\n", __func__,
			priv->full_duplex ? "FullDuplex" : "HalfDuplex");

	mutex_lock(&priv->lock);
	/* first reset the chip */
	enc28j60_soft_reset(priv);
	/* Clear ECON1 */
	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, ECON1, 0x00);
	priv->bank = 0;
	priv->hw_enable = false;
	priv->tx_retry_count = 0;
	priv->max_pk_counter = 0;
	priv->rxfilter = RXFILTER_NORMAL;
	/* enable address auto increment and voltage regulator powersave */
	nolock_regb_write(priv, ECON2, ECON2_AUTOINC | ECON2_VRPS);

	nolock_rxfifo_init(priv, RXSTART_INIT, RXEND_INIT);
	nolock_txfifo_init(priv, TXSTART_INIT, TXEND_INIT);
	mutex_unlock(&priv->lock);

	/*
	 * Check the RevID.
	 * If it's 0x00 or 0xFF probably the enc28j60 is not mounted or
	 * damaged
	 */
	reg = locked_regb_read(priv, EREVID);
	if (netif_msg_drv(priv))
		printk(KERN_INFO DRV_NAME ": chip RevID: 0x%02x\n", reg);
	if (reg == 0x00 || reg == 0xff) {
		if (netif_msg_drv(priv))
			printk(KERN_DEBUG DRV_NAME ": %s() Invalid RevId %d\n",
				__func__, reg);
		return 0;
	}

	/* default filter mode: (unicast OR broadcast) AND crc valid */
	locked_regb_write(priv, ERXFCON,
			    ERXFCON_UCEN | ERXFCON_CRCEN | ERXFCON_BCEN);

	/* enable MAC receive */
	locked_regb_write(priv, MACON1,
			    MACON1_MARXEN | MACON1_TXPAUS | MACON1_RXPAUS);
	/* enable automatic padding and CRC operations */
	if (priv->full_duplex) {
		locked_regb_write(priv, MACON3,
				    MACON3_PADCFG0 | MACON3_TXCRCEN |
				    MACON3_FRMLNEN | MACON3_FULDPX);
		/* set inter-frame gap (non-back-to-back) */
		locked_regb_write(priv, MAIPGL, 0x12);
		/* set inter-frame gap (back-to-back) */
		locked_regb_write(priv, MABBIPG, 0x15);
	} else {
		locked_regb_write(priv, MACON3,
				    MACON3_PADCFG0 | MACON3_TXCRCEN |
				    MACON3_FRMLNEN);
		locked_regb_write(priv, MACON4, 1 << 6);	/* DEFER bit */
		/* set inter-frame gap (non-back-to-back) */
		locked_regw_write(priv, MAIPGL, 0x0C12);
		/* set inter-frame gap (back-to-back) */
		locked_regb_write(priv, MABBIPG, 0x12);
	}
	/*
	 * MACLCON1 (default)
	 * MACLCON2 (default)
	 * Set the maximum packet size which the controller will accept
	 */
	locked_regw_write(priv, MAMXFLL, MAX_FRAMELEN);

	/* Configure LEDs */
	if (!enc28j60_phy_write(priv, PHLCON, ENC28J60_LAMPS_MODE))
		return 0;

	if (priv->full_duplex) {
		if (!enc28j60_phy_write(priv, PHCON1, PHCON1_PDPXMD))
			return 0;
		if (!enc28j60_phy_write(priv, PHCON2, 0x00))
			return 0;
	} else {
		if (!enc28j60_phy_write(priv, PHCON1, 0x00))
			return 0;
		if (!enc28j60_phy_write(priv, PHCON2, PHCON2_HDLDIS))
			return 0;
	}
	if (netif_msg_hw(priv))
		enc28j60_dump_regs(priv, "Hw initialized.");

	return 1;
}

static void enc28j60_hw_enable(struct enc28j60_net *priv)
{
	/* enable interrupts */
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() enabling interrupts.\n",
			__func__);

	enc28j60_phy_write(priv, PHIE, PHIE_PGEIE | PHIE_PLNKIE);

	mutex_lock(&priv->lock);
	nolock_reg_bfclr(priv, EIR, EIR_DMAIF | EIR_LINKIF |
			 EIR_TXIF | EIR_TXERIF | EIR_RXERIF | EIR_PKTIF);
	nolock_regb_write(priv, EIE, EIE_INTIE | EIE_PKTIE | EIE_LINKIE |
			  EIE_TXIE | EIE_TXERIE | EIE_RXERIE);

	/* enable receive logic */
	nolock_reg_bfset(priv, ECON1, ECON1_RXEN);
	priv->hw_enable = true;
	mutex_unlock(&priv->lock);
}

static void enc28j60_hw_disable(struct enc28j60_net *priv)
{
	mutex_lock(&priv->lock);
	/* disable interrutps and packet reception */
	nolock_regb_write(priv, EIE, 0x00);
	nolock_reg_bfclr(priv, ECON1, ECON1_RXEN);
	priv->hw_enable = false;
	mutex_unlock(&priv->lock);
}

static int
enc28j60_setlink(struct net_device *ndev, u8 autoneg, u16 speed, u8 duplex)
{
	struct enc28j60_net *priv = netdev_priv(ndev);
	int ret = 0;

	if (!priv->hw_enable) {
		/* link is in low power mode now; duplex setting
		 * will take effect on next enc28j60_hw_init().
		 */
		if (autoneg == AUTONEG_DISABLE && speed == SPEED_10)
			priv->full_duplex = (duplex == DUPLEX_FULL);
		else {
			if (netif_msg_link(priv))
				dev_warn(&ndev->dev,
					"unsupported link setting\n");
			ret = -EOPNOTSUPP;
		}
	} else {
		if (netif_msg_link(priv))
			dev_warn(&ndev->dev, "Warning: hw must be disabled "
				"to set link mode\n");
		ret = -EBUSY;
	}
	return ret;
}

/*
 * Read the Transmit Status Vector
 */
static void enc28j60_read_tsv(struct enc28j60_net *priv, u8 tsv[TSV_SIZE])
{
	int endptr;

	endptr = locked_regw_read(priv, ETXNDL);
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME ": reading TSV at addr:0x%04x\n",
			 endptr + 1);
	enc28j60_mem_read(priv, endptr + 1, sizeof(tsv), tsv);
}

static void enc28j60_dump_tsv(struct enc28j60_net *priv, const char *msg,
				u8 tsv[TSV_SIZE])
{
	u16 tmp1, tmp2;

	printk(KERN_DEBUG DRV_NAME ": %s - TSV:\n", msg);
	tmp1 = tsv[1];
	tmp1 <<= 8;
	tmp1 |= tsv[0];

	tmp2 = tsv[5];
	tmp2 <<= 8;
	tmp2 |= tsv[4];

	printk(KERN_DEBUG DRV_NAME ": ByteCount: %d, CollisionCount: %d,"
		" TotByteOnWire: %d\n", tmp1, tsv[2] & 0x0f, tmp2);
	printk(KERN_DEBUG DRV_NAME ": TxDone: %d, CRCErr:%d, LenChkErr: %d,"
		" LenOutOfRange: %d\n", TSV_GETBIT(tsv, TSV_TXDONE),
		TSV_GETBIT(tsv, TSV_TXCRCERROR),
		TSV_GETBIT(tsv, TSV_TXLENCHKERROR),
		TSV_GETBIT(tsv, TSV_TXLENOUTOFRANGE));
	printk(KERN_DEBUG DRV_NAME ": Multicast: %d, Broadcast: %d, "
		"PacketDefer: %d, ExDefer: %d\n",
		TSV_GETBIT(tsv, TSV_TXMULTICAST),
		TSV_GETBIT(tsv, TSV_TXBROADCAST),
		TSV_GETBIT(tsv, TSV_TXPACKETDEFER),
		TSV_GETBIT(tsv, TSV_TXEXDEFER));
	printk(KERN_DEBUG DRV_NAME ": ExCollision: %d, LateCollision: %d, "
		 "Giant: %d, Underrun: %d\n",
		 TSV_GETBIT(tsv, TSV_TXEXCOLLISION),
		 TSV_GETBIT(tsv, TSV_TXLATECOLLISION),
		 TSV_GETBIT(tsv, TSV_TXGIANT), TSV_GETBIT(tsv, TSV_TXUNDERRUN));
	printk(KERN_DEBUG DRV_NAME ": ControlFrame: %d, PauseFrame: %d, "
		 "BackPressApp: %d, VLanTagFrame: %d\n",
		 TSV_GETBIT(tsv, TSV_TXCONTROLFRAME),
		 TSV_GETBIT(tsv, TSV_TXPAUSEFRAME),
		 TSV_GETBIT(tsv, TSV_BACKPRESSUREAPP),
		 TSV_GETBIT(tsv, TSV_TXVLANTAGFRAME));
}

/*
 * Receive Status vector
 */
static void enc28j60_dump_rsv(struct enc28j60_net *priv, const char *msg,
			      u16 pk_ptr, int len, u16 sts)
{
	printk(KERN_DEBUG DRV_NAME ": %s - NextPk: 0x%04x - RSV:\n",
		msg, pk_ptr);
	printk(KERN_DEBUG DRV_NAME ": ByteCount: %d, DribbleNibble: %d\n", len,
		 RSV_GETBIT(sts, RSV_DRIBBLENIBBLE));
	printk(KERN_DEBUG DRV_NAME ": RxOK: %d, CRCErr:%d, LenChkErr: %d,"
		 " LenOutOfRange: %d\n", RSV_GETBIT(sts, RSV_RXOK),
		 RSV_GETBIT(sts, RSV_CRCERROR),
		 RSV_GETBIT(sts, RSV_LENCHECKERR),
		 RSV_GETBIT(sts, RSV_LENOUTOFRANGE));
	printk(KERN_DEBUG DRV_NAME ": Multicast: %d, Broadcast: %d, "
		 "LongDropEvent: %d, CarrierEvent: %d\n",
		 RSV_GETBIT(sts, RSV_RXMULTICAST),
		 RSV_GETBIT(sts, RSV_RXBROADCAST),
		 RSV_GETBIT(sts, RSV_RXLONGEVDROPEV),
		 RSV_GETBIT(sts, RSV_CARRIEREV));
	printk(KERN_DEBUG DRV_NAME ": ControlFrame: %d, PauseFrame: %d,"
		 " UnknownOp: %d, VLanTagFrame: %d\n",
		 RSV_GETBIT(sts, RSV_RXCONTROLFRAME),
		 RSV_GETBIT(sts, RSV_RXPAUSEFRAME),
		 RSV_GETBIT(sts, RSV_RXUNKNOWNOPCODE),
		 RSV_GETBIT(sts, RSV_RXTYPEVLAN));
}

static void dump_packet(const char *msg, int len, const char *data)
{
	printk(KERN_DEBUG DRV_NAME ": %s - packet len:%d\n", msg, len);
	print_hex_dump(KERN_DEBUG, "pk data: ", DUMP_PREFIX_OFFSET, 16, 1,
			data, len, true);
}

/*
 * Hardware receive function.
 * Read the buffer memory, update the FIFO pointer to free the buffer,
 * check the status vector and decrement the packet counter.
 */
static void enc28j60_hw_rx(struct net_device *ndev)
{
	struct enc28j60_net *priv = netdev_priv(ndev);
	struct sk_buff *skb = NULL;
	u16 erxrdpt, next_packet, rxstat;
	u8 rsv[RSV_SIZE];
	int len;

	if (netif_msg_rx_status(priv))
		printk(KERN_DEBUG DRV_NAME ": RX pk_addr:0x%04x\n",
			priv->next_pk_ptr);

	if (unlikely(priv->next_pk_ptr > RXEND_INIT)) {
		if (netif_msg_rx_err(priv))
			dev_err(&ndev->dev,
				"%s() Invalid packet address!! 0x%04x\n",
				__func__, priv->next_pk_ptr);
		/* packet address corrupted: reset RX logic */
		mutex_lock(&priv->lock);
		nolock_reg_bfclr(priv, ECON1, ECON1_RXEN);
		nolock_reg_bfset(priv, ECON1, ECON1_RXRST);
		nolock_reg_bfclr(priv, ECON1, ECON1_RXRST);
		nolock_rxfifo_init(priv, RXSTART_INIT, RXEND_INIT);
		nolock_reg_bfclr(priv, EIR, EIR_RXERIF);
		nolock_reg_bfset(priv, ECON1, ECON1_RXEN);
		mutex_unlock(&priv->lock);
		ndev->stats.rx_errors++;
		return;
	}
	/* Read next packet pointer and rx status vector */
	enc28j60_mem_read(priv, priv->next_pk_ptr, sizeof(rsv), rsv);

	next_packet = rsv[1];
	next_packet <<= 8;
	next_packet |= rsv[0];

	len = rsv[3];
	len <<= 8;
	len |= rsv[2];

	rxstat = rsv[5];
	rxstat <<= 8;
	rxstat |= rsv[4];

	if (netif_msg_rx_status(priv))
		enc28j60_dump_rsv(priv, __func__, next_packet, len, rxstat);

	if (!RSV_GETBIT(rxstat, RSV_RXOK)) {
		if (netif_msg_rx_err(priv))
			dev_err(&ndev->dev, "Rx Error (%04x)\n", rxstat);
		ndev->stats.rx_errors++;
		if (RSV_GETBIT(rxstat, RSV_CRCERROR))
			ndev->stats.rx_crc_errors++;
		if (RSV_GETBIT(rxstat, RSV_LENCHECKERR))
			ndev->stats.rx_frame_errors++;
	} else {
		skb = dev_alloc_skb(len + NET_IP_ALIGN);
		if (!skb) {
			if (netif_msg_rx_err(priv))
				dev_err(&ndev->dev,
					"out of memory for Rx'd frame\n");
			ndev->stats.rx_dropped++;
		} else {
			skb->dev = ndev;
			skb_reserve(skb, NET_IP_ALIGN);
			/* copy the packet from the receive buffer */
			enc28j60_mem_read(priv, priv->next_pk_ptr + sizeof(rsv),
					len, skb_put(skb, len));
			if (netif_msg_pktdata(priv))
				dump_packet(__func__, skb->len, skb->data);
			skb->protocol = eth_type_trans(skb, ndev);
			/* update statistics */
			ndev->stats.rx_packets++;
			ndev->stats.rx_bytes += len;
			netif_rx(skb);
		}
	}
	/*
	 * Move the RX read pointer to the start of the next
	 * received packet.
	 * This frees the memory we just read out
	 */
	erxrdpt = erxrdpt_workaround(next_packet, RXSTART_INIT, RXEND_INIT);
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() ERXRDPT:0x%04x\n",
			__func__, erxrdpt);

	mutex_lock(&priv->lock);
	nolock_regw_write(priv, ERXRDPTL, erxrdpt);
#ifdef CONFIG_ENC28J60_WRITEVERIFY
	if (netif_msg_drv(priv)) {
		u16 reg;
		reg = nolock_regw_read(priv, ERXRDPTL);
		if (reg != erxrdpt)
			printk(KERN_DEBUG DRV_NAME ": %s() ERXRDPT verify "
				"error (0x%04x - 0x%04x)\n", __func__,
				reg, erxrdpt);
	}
#endif
	priv->next_pk_ptr = next_packet;
	/* we are done with this packet, decrement the packet counter */
	nolock_reg_bfset(priv, ECON2, ECON2_PKTDEC);
	mutex_unlock(&priv->lock);
}

/*
 * Calculate free space in RxFIFO
 */
static int enc28j60_get_free_rxfifo(struct enc28j60_net *priv)
{
	int epkcnt, erxst, erxnd, erxwr, erxrd;
	int free_space;

	mutex_lock(&priv->lock);
	epkcnt = nolock_regb_read(priv, EPKTCNT);
	if (epkcnt >= 255)
		free_space = -1;
	else {
		erxst = nolock_regw_read(priv, ERXSTL);
		erxnd = nolock_regw_read(priv, ERXNDL);
		erxwr = nolock_regw_read(priv, ERXWRPTL);
		erxrd = nolock_regw_read(priv, ERXRDPTL);

		if (erxwr > erxrd)
			free_space = (erxnd - erxst) - (erxwr - erxrd);
		else if (erxwr == erxrd)
			free_space = (erxnd - erxst);
		else
			free_space = erxrd - erxwr - 1;
	}
	mutex_unlock(&priv->lock);
	if (netif_msg_rx_status(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() free_space = %d\n",
			__func__, free_space);
	return free_space;
}

/*
 * Access the PHY to determine link status
 */
static void enc28j60_check_link_status(struct net_device *ndev)
{
	struct enc28j60_net *priv = netdev_priv(ndev);
	u16 reg;
	int duplex;

	reg = enc28j60_phy_read(priv, PHSTAT2);
	if (netif_msg_hw(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() PHSTAT1: %04x, "
			"PHSTAT2: %04x\n", __func__,
			enc28j60_phy_read(priv, PHSTAT1), reg);
	duplex = reg & PHSTAT2_DPXSTAT;

	if (reg & PHSTAT2_LSTAT) {
		netif_carrier_on(ndev);
		if (netif_msg_ifup(priv))
			dev_info(&ndev->dev, "link up - %s\n",
				duplex ? "Full duplex" : "Half duplex");
	} else {
		if (netif_msg_ifdown(priv))
			dev_info(&ndev->dev, "link down\n");
		netif_carrier_off(ndev);
	}
}

static void enc28j60_tx_clear(struct net_device *ndev, bool err)
{
	struct enc28j60_net *priv = netdev_priv(ndev);

	if (err)
		ndev->stats.tx_errors++;
	else
		ndev->stats.tx_packets++;

	if (priv->tx_skb) {
		if (!err)
			ndev->stats.tx_bytes += priv->tx_skb->len;
		dev_kfree_skb(priv->tx_skb);
		priv->tx_skb = NULL;
	}
	locked_reg_bfclr(priv, ECON1, ECON1_TXRTS);
	netif_wake_queue(ndev);
}

/*
 * RX handler
 * ignore PKTIF because is unreliable! (look at the errata datasheet)
 * check EPKTCNT is the suggested workaround.
 * We don't need to clear interrupt flag, automatically done when
 * enc28j60_hw_rx() decrements the packet counter.
 * Returns how many packet processed.
 */
static int enc28j60_rx_interrupt(struct net_device *ndev)
{
	struct enc28j60_net *priv = netdev_priv(ndev);
	int pk_counter, ret;

	pk_counter = locked_regb_read(priv, EPKTCNT);
	if (pk_counter && netif_msg_intr(priv))
		printk(KERN_DEBUG DRV_NAME ": intRX, pk_cnt: %d\n", pk_counter);
	if (pk_counter > priv->max_pk_counter) {
		/* update statistics */
		priv->max_pk_counter = pk_counter;
		if (netif_msg_rx_status(priv) && priv->max_pk_counter > 1)
			printk(KERN_DEBUG DRV_NAME ": RX max_pk_cnt: %d\n",
				priv->max_pk_counter);
	}
	ret = pk_counter;
	while (pk_counter-- > 0)
		enc28j60_hw_rx(ndev);

	return ret;
}

static void enc28j60_irq_work_handler(struct work_struct *work)
{
	struct enc28j60_net *priv =
		container_of(work, struct enc28j60_net, irq_work);
	struct net_device *ndev = priv->netdev;
	int intflags, loop;

	if (netif_msg_intr(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() enter\n", __func__);
	/* disable further interrupts */
	locked_reg_bfclr(priv, EIE, EIE_INTIE);

	do {
		loop = 0;
		intflags = locked_regb_read(priv, EIR);
		/* DMA interrupt handler (not currently used) */
		if ((intflags & EIR_DMAIF) != 0) {
			loop++;
			if (netif_msg_intr(priv))
				printk(KERN_DEBUG DRV_NAME
					": intDMA(%d)\n", loop);
			locked_reg_bfclr(priv, EIR, EIR_DMAIF);
		}
		/* LINK changed handler */
		if ((intflags & EIR_LINKIF) != 0) {
			loop++;
			if (netif_msg_intr(priv))
				printk(KERN_DEBUG DRV_NAME
					": intLINK(%d)\n", loop);
			enc28j60_check_link_status(ndev);
			/* read PHIR to clear the flag */
			enc28j60_phy_read(priv, PHIR);
		}
		/* TX complete handler */
		if ((intflags & EIR_TXIF) != 0) {
			bool err = false;
			loop++;
			if (netif_msg_intr(priv))
				printk(KERN_DEBUG DRV_NAME
					": intTX(%d)\n", loop);
			priv->tx_retry_count = 0;
			if (locked_regb_read(priv, ESTAT) & ESTAT_TXABRT) {
				if (netif_msg_tx_err(priv))
					dev_err(&ndev->dev,
						"Tx Error (aborted)\n");
				err = true;
			}
			if (netif_msg_tx_done(priv)) {
				u8 tsv[TSV_SIZE];
				enc28j60_read_tsv(priv, tsv);
				enc28j60_dump_tsv(priv, "Tx Done", tsv);
			}
			enc28j60_tx_clear(ndev, err);
			locked_reg_bfclr(priv, EIR, EIR_TXIF);
		}
		/* TX Error handler */
		if ((intflags & EIR_TXERIF) != 0) {
			u8 tsv[TSV_SIZE];

			loop++;
			if (netif_msg_intr(priv))
				printk(KERN_DEBUG DRV_NAME
					": intTXErr(%d)\n", loop);
			locked_reg_bfclr(priv, ECON1, ECON1_TXRTS);
			enc28j60_read_tsv(priv, tsv);
			if (netif_msg_tx_err(priv))
				enc28j60_dump_tsv(priv, "Tx Error", tsv);
			/* Reset TX logic */
			mutex_lock(&priv->lock);
			nolock_reg_bfset(priv, ECON1, ECON1_TXRST);
			nolock_reg_bfclr(priv, ECON1, ECON1_TXRST);
			nolock_txfifo_init(priv, TXSTART_INIT, TXEND_INIT);
			mutex_unlock(&priv->lock);
			/* Transmit Late collision check for retransmit */
			if (TSV_GETBIT(tsv, TSV_TXLATECOLLISION)) {
				if (netif_msg_tx_err(priv))
					printk(KERN_DEBUG DRV_NAME
						": LateCollision TXErr (%d)\n",
						priv->tx_retry_count);
				if (priv->tx_retry_count++ < MAX_TX_RETRYCOUNT)
					locked_reg_bfset(priv, ECON1,
							   ECON1_TXRTS);
				else
					enc28j60_tx_clear(ndev, true);
			} else
				enc28j60_tx_clear(ndev, true);
			locked_reg_bfclr(priv, EIR, EIR_TXERIF);
		}
		/* RX Error handler */
		if ((intflags & EIR_RXERIF) != 0) {
			loop++;
			if (netif_msg_intr(priv))
				printk(KERN_DEBUG DRV_NAME
					": intRXErr(%d)\n", loop);
			/* Check free FIFO space to flag RX overrun */
			if (enc28j60_get_free_rxfifo(priv) <= 0) {
				if (netif_msg_rx_err(priv))
					printk(KERN_DEBUG DRV_NAME
						": RX Overrun\n");
				ndev->stats.rx_dropped++;
			}
			locked_reg_bfclr(priv, EIR, EIR_RXERIF);
		}
		/* RX handler */
		if (enc28j60_rx_interrupt(ndev))
			loop++;
	} while (loop);

	/* re-enable interrupts */
	locked_reg_bfset(priv, EIE, EIE_INTIE);
	if (netif_msg_intr(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() exit\n", __func__);
}

/*
 * Hardware transmit function.
 * Fill the buffer memory and send the contents of the transmit buffer
 * onto the network
 */
static void enc28j60_hw_tx(struct enc28j60_net *priv)
{
	if (netif_msg_tx_queued(priv))
		printk(KERN_DEBUG DRV_NAME
			": Tx Packet Len:%d\n", priv->tx_skb->len);

	if (netif_msg_pktdata(priv))
		dump_packet(__func__,
			    priv->tx_skb->len, priv->tx_skb->data);
	enc28j60_packet_write(priv, priv->tx_skb->len, priv->tx_skb->data);

#ifdef CONFIG_ENC28J60_WRITEVERIFY
	/* readback and verify written data */
	if (netif_msg_drv(priv)) {
		int test_len, k;
		u8 test_buf[64]; /* limit the test to the first 64 bytes */
		int okflag;

		test_len = priv->tx_skb->len;
		if (test_len > sizeof(test_buf))
			test_len = sizeof(test_buf);

		/* + 1 to skip control byte */
		enc28j60_mem_read(priv, TXSTART_INIT + 1, test_len, test_buf);
		okflag = 1;
		for (k = 0; k < test_len; k++) {
			if (priv->tx_skb->data[k] != test_buf[k]) {
				printk(KERN_DEBUG DRV_NAME
					 ": Error, %d location differ: "
					 "0x%02x-0x%02x\n", k,
					 priv->tx_skb->data[k], test_buf[k]);
				okflag = 0;
			}
		}
		if (!okflag)
			printk(KERN_DEBUG DRV_NAME ": Tx write buffer, "
				"verify ERROR!\n");
	}
#endif
	/* set TX request flag */
	locked_reg_bfset(priv, ECON1, ECON1_TXRTS);
}

static int enc28j60_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct enc28j60_net *priv = netdev_priv(dev);

	if (netif_msg_tx_queued(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() enter\n", __func__);

	/* If some error occurs while trying to transmit this
	 * packet, you should return '1' from this function.
	 * In such a case you _may not_ do anything to the
	 * SKB, it is still owned by the network queueing
	 * layer when an error is returned.  This means you
	 * may not modify any SKB fields, you may not free
	 * the SKB, etc.
	 */
	netif_stop_queue(dev);

	/* save the timestamp */
	priv->netdev->trans_start = jiffies;
	/* Remember the skb for deferred processing */
	priv->tx_skb = skb;
	schedule_work(&priv->tx_work);

	return 0;
}

static void enc28j60_tx_work_handler(struct work_struct *work)
{
	struct enc28j60_net *priv =
		container_of(work, struct enc28j60_net, tx_work);

	/* actual delivery of data */
	enc28j60_hw_tx(priv);
}

static irqreturn_t enc28j60_irq(int irq, void *dev_id)
{
	struct enc28j60_net *priv = dev_id;

	/*
	 * Can't do anything in interrupt context because we need to
	 * block (spi_sync() is blocking) so fire of the interrupt
	 * handling workqueue.
	 * Remember that we access enc28j60 registers through SPI bus
	 * via spi_sync() call.
	 */
	schedule_work(&priv->irq_work);

	return IRQ_HANDLED;
}

static void enc28j60_tx_timeout(struct net_device *ndev)
{
	struct enc28j60_net *priv = netdev_priv(ndev);

	if (netif_msg_timer(priv))
		dev_err(&ndev->dev, DRV_NAME " tx timeout\n");

	ndev->stats.tx_errors++;
	/* can't restart safely under softirq */
	schedule_work(&priv->restart_work);
}

/*
 * Open/initialize the board. This is called (in the current kernel)
 * sometime after booting when the 'ifconfig' program is run.
 *
 * This routine should set everything up anew at each open, even
 * registers that "should" only need to be set once at boot, so that
 * there is non-reboot way to recover if something goes wrong.
 */
static int enc28j60_net_open(struct net_device *dev)
{
	struct enc28j60_net *priv = netdev_priv(dev);

	if (netif_msg_drv(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() enter\n", __func__);

	if (!is_valid_ether_addr(dev->dev_addr)) {
		if (netif_msg_ifup(priv))
			dev_err(&dev->dev, "invalid MAC address %pM\n",
				dev->dev_addr);
		return -EADDRNOTAVAIL;
	}
	/* Reset the hardware here (and take it out of low power mode) */
	enc28j60_lowpower(priv, false);
	enc28j60_hw_disable(priv);
	if (!enc28j60_hw_init(priv)) {
		if (netif_msg_ifup(priv))
			dev_err(&dev->dev, "hw_reset() failed\n");
		return -EINVAL;
	}
	/* Update the MAC address (in case user has changed it) */
	enc28j60_set_hw_macaddr(dev);
	/* Enable interrupts */
	enc28j60_hw_enable(priv);
	/* check link status */
	enc28j60_check_link_status(dev);
	/* We are now ready to accept transmit requests from
	 * the queueing layer of the networking.
	 */
	netif_start_queue(dev);

	return 0;
}

/* The inverse routine to net_open(). */
static int enc28j60_net_close(struct net_device *dev)
{
	struct enc28j60_net *priv = netdev_priv(dev);

	if (netif_msg_drv(priv))
		printk(KERN_DEBUG DRV_NAME ": %s() enter\n", __func__);

	enc28j60_hw_disable(priv);
	enc28j60_lowpower(priv, true);
	netif_stop_queue(dev);

	return 0;
}

/*
 * Set or clear the multicast filter for this adapter
 * num_addrs == -1	Promiscuous mode, receive all packets
 * num_addrs == 0	Normal mode, filter out multicast packets
 * num_addrs > 0	Multicast mode, receive normal and MC packets
 */
static void enc28j60_set_multicast_list(struct net_device *dev)
{
	struct enc28j60_net *priv = netdev_priv(dev);
	int oldfilter = priv->rxfilter;

	if (dev->flags & IFF_PROMISC) {
		if (netif_msg_link(priv))
			dev_info(&dev->dev, "promiscuous mode\n");
		priv->rxfilter = RXFILTER_PROMISC;
	} else if ((dev->flags & IFF_ALLMULTI) || dev->mc_count) {
		if (netif_msg_link(priv))
			dev_info(&dev->dev, "%smulticast mode\n",
				(dev->flags & IFF_ALLMULTI) ? "all-" : "");
		priv->rxfilter = RXFILTER_MULTI;
	} else {
		if (netif_msg_link(priv))
			dev_info(&dev->dev, "normal mode\n");
		priv->rxfilter = RXFILTER_NORMAL;
	}

	if (oldfilter != priv->rxfilter)
		schedule_work(&priv->setrx_work);
}

static void enc28j60_setrx_work_handler(struct work_struct *work)
{
	struct enc28j60_net *priv =
		container_of(work, struct enc28j60_net, setrx_work);

	if (priv->rxfilter == RXFILTER_PROMISC) {
		if (netif_msg_drv(priv))
			printk(KERN_DEBUG DRV_NAME ": promiscuous mode\n");
		locked_regb_write(priv, ERXFCON, 0x00);
	} else if (priv->rxfilter == RXFILTER_MULTI) {
		if (netif_msg_drv(priv))
			printk(KERN_DEBUG DRV_NAME ": multicast mode\n");
		locked_regb_write(priv, ERXFCON,
					ERXFCON_UCEN | ERXFCON_CRCEN |
					ERXFCON_BCEN | ERXFCON_MCEN);
	} else {
		if (netif_msg_drv(priv))
			printk(KERN_DEBUG DRV_NAME ": normal mode\n");
		locked_regb_write(priv, ERXFCON,
					ERXFCON_UCEN | ERXFCON_CRCEN |
					ERXFCON_BCEN);
	}
}

static void enc28j60_restart_work_handler(struct work_struct *work)
{
	struct enc28j60_net *priv =
			container_of(work, struct enc28j60_net, restart_work);
	struct net_device *ndev = priv->netdev;
	int ret;

	rtnl_lock();
	if (netif_running(ndev)) {
		enc28j60_net_close(ndev);
		ret = enc28j60_net_open(ndev);
		if (unlikely(ret)) {
			dev_info(&ndev->dev, " could not restart %d\n", ret);
			dev_close(ndev);
		}
	}
	rtnl_unlock();
}

/* ......................... ETHTOOL SUPPORT ........................... */

static void
enc28j60_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
	strlcpy(info->bus_info,
		dev->dev.parent->bus_id, sizeof(info->bus_info));
}

static int
enc28j60_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	struct enc28j60_net *priv = netdev_priv(dev);

	cmd->transceiver = XCVR_INTERNAL;
	cmd->supported	= SUPPORTED_10baseT_Half
			| SUPPORTED_10baseT_Full
			| SUPPORTED_TP;
	cmd->speed	= SPEED_10;
	cmd->duplex	= priv->full_duplex ? DUPLEX_FULL : DUPLEX_HALF;
	cmd->port	= PORT_TP;
	cmd->autoneg	= AUTONEG_DISABLE;

	return 0;
}

static int
enc28j60_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	return enc28j60_setlink(dev, cmd->autoneg, cmd->speed, cmd->duplex);
}

static u32 enc28j60_get_msglevel(struct net_device *dev)
{
	struct enc28j60_net *priv = netdev_priv(dev);
	return priv->msg_enable;
}

static void enc28j60_set_msglevel(struct net_device *dev, u32 val)
{
	struct enc28j60_net *priv = netdev_priv(dev);
	priv->msg_enable = val;
}

static const struct ethtool_ops enc28j60_ethtool_ops = {
	.get_settings	= enc28j60_get_settings,
	.set_settings	= enc28j60_set_settings,
	.get_drvinfo	= enc28j60_get_drvinfo,
	.get_msglevel	= enc28j60_get_msglevel,
	.set_msglevel	= enc28j60_set_msglevel,
};

static int enc28j60_chipset_init(struct net_device *dev)
{
	struct enc28j60_net *priv = netdev_priv(dev);

	return enc28j60_hw_init(priv);
}

static int __devinit enc28j60_probe(struct spi_device *spi)
{
	struct net_device *dev;
	struct enc28j60_net *priv;
	int ret = 0;

	if (netif_msg_drv(&debug))
		dev_info(&spi->dev, DRV_NAME " Ethernet driver %s loaded\n",
			DRV_VERSION);

	dev = alloc_etherdev(sizeof(struct enc28j60_net));
	if (!dev) {
		if (netif_msg_drv(&debug))
			dev_err(&spi->dev, DRV_NAME
				": unable to alloc new ethernet\n");
		ret = -ENOMEM;
		goto error_alloc;
	}
	priv = netdev_priv(dev);

	priv->netdev = dev;	/* priv to netdev reference */
	priv->spi = spi;	/* priv to spi reference */
	priv->msg_enable = netif_msg_init(debug.msg_enable,
						ENC28J60_MSG_DEFAULT);
	mutex_init(&priv->lock);
	INIT_WORK(&priv->tx_work, enc28j60_tx_work_handler);
	INIT_WORK(&priv->setrx_work, enc28j60_setrx_work_handler);
	INIT_WORK(&priv->irq_work, enc28j60_irq_work_handler);
	INIT_WORK(&priv->restart_work, enc28j60_restart_work_handler);
	dev_set_drvdata(&spi->dev, priv);	/* spi to priv reference */
	SET_NETDEV_DEV(dev, &spi->dev);

	if (!enc28j60_chipset_init(dev)) {
		if (netif_msg_probe(priv))
			dev_info(&spi->dev, DRV_NAME " chip not found\n");
		ret = -EIO;
		goto error_irq;
	}
	random_ether_addr(dev->dev_addr);
	enc28j60_set_hw_macaddr(dev);

	/* Board setup must set the relevant edge trigger type;
	 * level triggers won't currently work.
	 */
	ret = request_irq(spi->irq, enc28j60_irq, 0, DRV_NAME, priv);
	if (ret < 0) {
		if (netif_msg_probe(priv))
			dev_err(&spi->dev, DRV_NAME ": request irq %d failed "
				"(ret = %d)\n", spi->irq, ret);
		goto error_irq;
	}

	dev->if_port = IF_PORT_10BASET;
	dev->irq = spi->irq;
	dev->open = enc28j60_net_open;
	dev->stop = enc28j60_net_close;
	dev->hard_start_xmit = enc28j60_send_packet;
	dev->set_multicast_list = &enc28j60_set_multicast_list;
	dev->set_mac_address = enc28j60_set_mac_address;
	dev->tx_timeout = &enc28j60_tx_timeout;
	dev->watchdog_timeo = TX_TIMEOUT;
	SET_ETHTOOL_OPS(dev, &enc28j60_ethtool_ops);

	enc28j60_lowpower(priv, true);

	ret = register_netdev(dev);
	if (ret) {
		if (netif_msg_probe(priv))
			dev_err(&spi->dev, "register netdev " DRV_NAME
				" failed (ret = %d)\n", ret);
		goto error_register;
	}
	dev_info(&dev->dev, DRV_NAME " driver registered\n");

	return 0;

error_register:
	free_irq(spi->irq, priv);
error_irq:
	free_netdev(dev);
error_alloc:
	return ret;
}

static int __devexit enc28j60_remove(struct spi_device *spi)
{
	struct enc28j60_net *priv = dev_get_drvdata(&spi->dev);

	if (netif_msg_drv(priv))
		printk(KERN_DEBUG DRV_NAME ": remove\n");

	unregister_netdev(priv->netdev);
	free_irq(spi->irq, priv);
	free_netdev(priv->netdev);

	return 0;
}

static struct spi_driver enc28j60_driver = {
	.driver = {
		   .name = DRV_NAME,
		   .owner = THIS_MODULE,
	 },
	.probe = enc28j60_probe,
	.remove = __devexit_p(enc28j60_remove),
};

static int __init enc28j60_init(void)
{
	msec20_to_jiffies = msecs_to_jiffies(20);

	return spi_register_driver(&enc28j60_driver);
}

module_init(enc28j60_init);

static void __exit enc28j60_exit(void)
{
	spi_unregister_driver(&enc28j60_driver);
}

module_exit(enc28j60_exit);

MODULE_DESCRIPTION(DRV_NAME " ethernet driver");
MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
MODULE_LICENSE("GPL");
module_param_named(debug, debug.msg_enable, int, 0);
MODULE_PARM_DESC(debug, "Debug verbosity level (0=none, ..., ffff=all)");