Free Electrons

Embedded Linux Experts

   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
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
/*
 * Janz MODULbus VMOD-ICAN3 CAN Interface Driver
 *
 * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>

#include <linux/netdevice.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>

#include <linux/mfd/janz.h>
#include <asm/io.h>

/* the DPM has 64k of memory, organized into 256x 256 byte pages */
#define DPM_NUM_PAGES		256
#define DPM_PAGE_SIZE		256
#define DPM_PAGE_ADDR(p)	((p) * DPM_PAGE_SIZE)

/* JANZ ICAN3 "old-style" host interface queue page numbers */
#define QUEUE_OLD_CONTROL	0
#define QUEUE_OLD_RB0		1
#define QUEUE_OLD_RB1		2
#define QUEUE_OLD_WB0		3
#define QUEUE_OLD_WB1		4

/* Janz ICAN3 "old-style" host interface control registers */
#define MSYNC_PEER		0x00		/* ICAN only */
#define MSYNC_LOCL		0x01		/* host only */
#define TARGET_RUNNING		0x02

#define MSYNC_RB0		0x01
#define MSYNC_RB1		0x02
#define MSYNC_RBLW		0x04
#define MSYNC_RB_MASK		(MSYNC_RB0 | MSYNC_RB1)

#define MSYNC_WB0		0x10
#define MSYNC_WB1		0x20
#define MSYNC_WBLW		0x40
#define MSYNC_WB_MASK		(MSYNC_WB0 | MSYNC_WB1)

/* Janz ICAN3 "new-style" host interface queue page numbers */
#define QUEUE_TOHOST		5
#define QUEUE_FROMHOST_MID	6
#define QUEUE_FROMHOST_HIGH	7
#define QUEUE_FROMHOST_LOW	8

/* The first free page in the DPM is #9 */
#define DPM_FREE_START		9

/* Janz ICAN3 "new-style" and "fast" host interface descriptor flags */
#define DESC_VALID		0x80
#define DESC_WRAP		0x40
#define DESC_INTERRUPT		0x20
#define DESC_IVALID		0x10
#define DESC_LEN(len)		(len)

/* Janz ICAN3 Firmware Messages */
#define MSG_CONNECTI		0x02
#define MSG_DISCONNECT		0x03
#define MSG_IDVERS		0x04
#define MSG_MSGLOST		0x05
#define MSG_NEWHOSTIF		0x08
#define MSG_INQUIRY		0x0a
#define MSG_SETAFILMASK		0x10
#define MSG_INITFDPMQUEUE	0x11
#define MSG_HWCONF		0x12
#define MSG_FMSGLOST		0x15
#define MSG_CEVTIND		0x37
#define MSG_CBTRREQ		0x41
#define MSG_COFFREQ		0x42
#define MSG_CONREQ		0x43
#define MSG_CCONFREQ		0x47

/*
 * Janz ICAN3 CAN Inquiry Message Types
 *
 * NOTE: there appears to be a firmware bug here. You must send
 * NOTE: INQUIRY_STATUS and expect to receive an INQUIRY_EXTENDED
 * NOTE: response. The controller never responds to a message with
 * NOTE: the INQUIRY_EXTENDED subspec :(
 */
#define INQUIRY_STATUS		0x00
#define INQUIRY_TERMINATION	0x01
#define INQUIRY_EXTENDED	0x04

/* Janz ICAN3 CAN Set Acceptance Filter Mask Message Types */
#define SETAFILMASK_REJECT	0x00
#define SETAFILMASK_FASTIF	0x02

/* Janz ICAN3 CAN Hardware Configuration Message Types */
#define HWCONF_TERMINATE_ON	0x01
#define HWCONF_TERMINATE_OFF	0x00

/* Janz ICAN3 CAN Event Indication Message Types */
#define CEVTIND_EI		0x01
#define CEVTIND_DOI		0x02
#define CEVTIND_LOST		0x04
#define CEVTIND_FULL		0x08
#define CEVTIND_BEI		0x10

#define CEVTIND_CHIP_SJA1000	0x02

#define ICAN3_BUSERR_QUOTA_MAX	255

/* Janz ICAN3 CAN Frame Conversion */
#define ICAN3_SNGL	0x02
#define ICAN3_ECHO	0x10
#define ICAN3_EFF_RTR	0x40
#define ICAN3_SFF_RTR	0x10
#define ICAN3_EFF	0x80

#define ICAN3_CAN_TYPE_MASK	0x0f
#define ICAN3_CAN_TYPE_SFF	0x00
#define ICAN3_CAN_TYPE_EFF	0x01

#define ICAN3_CAN_DLC_MASK	0x0f

/*
 * SJA1000 Status and Error Register Definitions
 *
 * Copied from drivers/net/can/sja1000/sja1000.h
 */

/* status register content */
#define SR_BS		0x80
#define SR_ES		0x40
#define SR_TS		0x20
#define SR_RS		0x10
#define SR_TCS		0x08
#define SR_TBS		0x04
#define SR_DOS		0x02
#define SR_RBS		0x01

#define SR_CRIT (SR_BS|SR_ES)

/* ECC register */
#define ECC_SEG		0x1F
#define ECC_DIR		0x20
#define ECC_ERR		6
#define ECC_BIT		0x00
#define ECC_FORM	0x40
#define ECC_STUFF	0x80
#define ECC_MASK	0xc0

/* Number of buffers for use in the "new-style" host interface */
#define ICAN3_NEW_BUFFERS	16

/* Number of buffers for use in the "fast" host interface */
#define ICAN3_TX_BUFFERS	512
#define ICAN3_RX_BUFFERS	1024

/* SJA1000 Clock Input */
#define ICAN3_CAN_CLOCK		8000000

/* Driver Name */
#define DRV_NAME "janz-ican3"

/* DPM Control Registers -- starts at offset 0x100 in the MODULbus registers */
struct ican3_dpm_control {
	/* window address register */
	u8 window_address;
	u8 unused1;

	/*
	 * Read access: clear interrupt from microcontroller
	 * Write access: send interrupt to microcontroller
	 */
	u8 interrupt;
	u8 unused2;

	/* write-only: reset all hardware on the module */
	u8 hwreset;
	u8 unused3;

	/* write-only: generate an interrupt to the TPU */
	u8 tpuinterrupt;
};

struct ican3_dev {

	/* must be the first member */
	struct can_priv can;

	/* CAN network device */
	struct net_device *ndev;
	struct napi_struct napi;

	/* Device for printing */
	struct device *dev;

	/* module number */
	unsigned int num;

	/* base address of registers and IRQ */
	struct janz_cmodio_onboard_regs __iomem *ctrl;
	struct ican3_dpm_control __iomem *dpmctrl;
	void __iomem *dpm;
	int irq;

	/* CAN bus termination status */
	struct completion termination_comp;
	bool termination_enabled;

	/* CAN bus error status registers */
	struct completion buserror_comp;
	struct can_berr_counter bec;

	/* old and new style host interface */
	unsigned int iftype;

	/* queue for echo packets */
	struct sk_buff_head echoq;

	/*
	 * Any function which changes the current DPM page must hold this
	 * lock while it is performing data accesses. This ensures that the
	 * function will not be preempted and end up reading data from a
	 * different DPM page than it expects.
	 */
	spinlock_t lock;

	/* new host interface */
	unsigned int rx_int;
	unsigned int rx_num;
	unsigned int tx_num;

	/* fast host interface */
	unsigned int fastrx_start;
	unsigned int fastrx_num;
	unsigned int fasttx_start;
	unsigned int fasttx_num;

	/* first free DPM page */
	unsigned int free_page;
};

struct ican3_msg {
	u8 control;
	u8 spec;
	__le16 len;
	u8 data[252];
};

struct ican3_new_desc {
	u8 control;
	u8 pointer;
};

struct ican3_fast_desc {
	u8 control;
	u8 command;
	u8 data[14];
};

/* write to the window basic address register */
static inline void ican3_set_page(struct ican3_dev *mod, unsigned int page)
{
	BUG_ON(page >= DPM_NUM_PAGES);
	iowrite8(page, &mod->dpmctrl->window_address);
}

/*
 * ICAN3 "old-style" host interface
 */

/*
 * Receive a message from the ICAN3 "old-style" firmware interface
 *
 * LOCKING: must hold mod->lock
 *
 * returns 0 on success, -ENOMEM when no message exists
 */
static int ican3_old_recv_msg(struct ican3_dev *mod, struct ican3_msg *msg)
{
	unsigned int mbox, mbox_page;
	u8 locl, peer, xord;

	/* get the MSYNC registers */
	ican3_set_page(mod, QUEUE_OLD_CONTROL);
	peer = ioread8(mod->dpm + MSYNC_PEER);
	locl = ioread8(mod->dpm + MSYNC_LOCL);
	xord = locl ^ peer;

	if ((xord & MSYNC_RB_MASK) == 0x00) {
		dev_dbg(mod->dev, "no mbox for reading\n");
		return -ENOMEM;
	}

	/* find the first free mbox to read */
	if ((xord & MSYNC_RB_MASK) == MSYNC_RB_MASK)
		mbox = (xord & MSYNC_RBLW) ? MSYNC_RB0 : MSYNC_RB1;
	else
		mbox = (xord & MSYNC_RB0) ? MSYNC_RB0 : MSYNC_RB1;

	/* copy the message */
	mbox_page = (mbox == MSYNC_RB0) ? QUEUE_OLD_RB0 : QUEUE_OLD_RB1;
	ican3_set_page(mod, mbox_page);
	memcpy_fromio(msg, mod->dpm, sizeof(*msg));

	/*
	 * notify the firmware that the read buffer is available
	 * for it to fill again
	 */
	locl ^= mbox;

	ican3_set_page(mod, QUEUE_OLD_CONTROL);
	iowrite8(locl, mod->dpm + MSYNC_LOCL);
	return 0;
}

/*
 * Send a message through the "old-style" firmware interface
 *
 * LOCKING: must hold mod->lock
 *
 * returns 0 on success, -ENOMEM when no free space exists
 */
static int ican3_old_send_msg(struct ican3_dev *mod, struct ican3_msg *msg)
{
	unsigned int mbox, mbox_page;
	u8 locl, peer, xord;

	/* get the MSYNC registers */
	ican3_set_page(mod, QUEUE_OLD_CONTROL);
	peer = ioread8(mod->dpm + MSYNC_PEER);
	locl = ioread8(mod->dpm + MSYNC_LOCL);
	xord = locl ^ peer;

	if ((xord & MSYNC_WB_MASK) == MSYNC_WB_MASK) {
		dev_err(mod->dev, "no mbox for writing\n");
		return -ENOMEM;
	}

	/* calculate a free mbox to use */
	mbox = (xord & MSYNC_WB0) ? MSYNC_WB1 : MSYNC_WB0;

	/* copy the message to the DPM */
	mbox_page = (mbox == MSYNC_WB0) ? QUEUE_OLD_WB0 : QUEUE_OLD_WB1;
	ican3_set_page(mod, mbox_page);
	memcpy_toio(mod->dpm, msg, sizeof(*msg));

	locl ^= mbox;
	if (mbox == MSYNC_WB1)
		locl |= MSYNC_WBLW;

	ican3_set_page(mod, QUEUE_OLD_CONTROL);
	iowrite8(locl, mod->dpm + MSYNC_LOCL);
	return 0;
}

/*
 * ICAN3 "new-style" Host Interface Setup
 */

static void ican3_init_new_host_interface(struct ican3_dev *mod)
{
	struct ican3_new_desc desc;
	unsigned long flags;
	void __iomem *dst;
	int i;

	spin_lock_irqsave(&mod->lock, flags);

	/* setup the internal datastructures for RX */
	mod->rx_num = 0;
	mod->rx_int = 0;

	/* tohost queue descriptors are in page 5 */
	ican3_set_page(mod, QUEUE_TOHOST);
	dst = mod->dpm;

	/* initialize the tohost (rx) queue descriptors: pages 9-24 */
	for (i = 0; i < ICAN3_NEW_BUFFERS; i++) {
		desc.control = DESC_INTERRUPT | DESC_LEN(1); /* I L=1 */
		desc.pointer = mod->free_page;

		/* set wrap flag on last buffer */
		if (i == ICAN3_NEW_BUFFERS - 1)
			desc.control |= DESC_WRAP;

		memcpy_toio(dst, &desc, sizeof(desc));
		dst += sizeof(desc);
		mod->free_page++;
	}

	/* fromhost (tx) mid queue descriptors are in page 6 */
	ican3_set_page(mod, QUEUE_FROMHOST_MID);
	dst = mod->dpm;

	/* setup the internal datastructures for TX */
	mod->tx_num = 0;

	/* initialize the fromhost mid queue descriptors: pages 25-40 */
	for (i = 0; i < ICAN3_NEW_BUFFERS; i++) {
		desc.control = DESC_VALID | DESC_LEN(1); /* V L=1 */
		desc.pointer = mod->free_page;

		/* set wrap flag on last buffer */
		if (i == ICAN3_NEW_BUFFERS - 1)
			desc.control |= DESC_WRAP;

		memcpy_toio(dst, &desc, sizeof(desc));
		dst += sizeof(desc);
		mod->free_page++;
	}

	/* fromhost hi queue descriptors are in page 7 */
	ican3_set_page(mod, QUEUE_FROMHOST_HIGH);
	dst = mod->dpm;

	/* initialize only a single buffer in the fromhost hi queue (unused) */
	desc.control = DESC_VALID | DESC_WRAP | DESC_LEN(1); /* VW L=1 */
	desc.pointer = mod->free_page;
	memcpy_toio(dst, &desc, sizeof(desc));
	mod->free_page++;

	/* fromhost low queue descriptors are in page 8 */
	ican3_set_page(mod, QUEUE_FROMHOST_LOW);
	dst = mod->dpm;

	/* initialize only a single buffer in the fromhost low queue (unused) */
	desc.control = DESC_VALID | DESC_WRAP | DESC_LEN(1); /* VW L=1 */
	desc.pointer = mod->free_page;
	memcpy_toio(dst, &desc, sizeof(desc));
	mod->free_page++;

	spin_unlock_irqrestore(&mod->lock, flags);
}

/*
 * ICAN3 Fast Host Interface Setup
 */

static void ican3_init_fast_host_interface(struct ican3_dev *mod)
{
	struct ican3_fast_desc desc;
	unsigned long flags;
	unsigned int addr;
	void __iomem *dst;
	int i;

	spin_lock_irqsave(&mod->lock, flags);

	/* save the start recv page */
	mod->fastrx_start = mod->free_page;
	mod->fastrx_num = 0;

	/* build a single fast tohost queue descriptor */
	memset(&desc, 0, sizeof(desc));
	desc.control = 0x00;
	desc.command = 1;

	/* build the tohost queue descriptor ring in memory */
	addr = 0;
	for (i = 0; i < ICAN3_RX_BUFFERS; i++) {

		/* set the wrap bit on the last buffer */
		if (i == ICAN3_RX_BUFFERS - 1)
			desc.control |= DESC_WRAP;

		/* switch to the correct page */
		ican3_set_page(mod, mod->free_page);

		/* copy the descriptor to the DPM */
		dst = mod->dpm + addr;
		memcpy_toio(dst, &desc, sizeof(desc));
		addr += sizeof(desc);

		/* move to the next page if necessary */
		if (addr >= DPM_PAGE_SIZE) {
			addr = 0;
			mod->free_page++;
		}
	}

	/* make sure we page-align the next queue */
	if (addr != 0)
		mod->free_page++;

	/* save the start xmit page */
	mod->fasttx_start = mod->free_page;
	mod->fasttx_num = 0;

	/* build a single fast fromhost queue descriptor */
	memset(&desc, 0, sizeof(desc));
	desc.control = DESC_VALID;
	desc.command = 1;

	/* build the fromhost queue descriptor ring in memory */
	addr = 0;
	for (i = 0; i < ICAN3_TX_BUFFERS; i++) {

		/* set the wrap bit on the last buffer */
		if (i == ICAN3_TX_BUFFERS - 1)
			desc.control |= DESC_WRAP;

		/* switch to the correct page */
		ican3_set_page(mod, mod->free_page);

		/* copy the descriptor to the DPM */
		dst = mod->dpm + addr;
		memcpy_toio(dst, &desc, sizeof(desc));
		addr += sizeof(desc);

		/* move to the next page if necessary */
		if (addr >= DPM_PAGE_SIZE) {
			addr = 0;
			mod->free_page++;
		}
	}

	spin_unlock_irqrestore(&mod->lock, flags);
}

/*
 * ICAN3 "new-style" Host Interface Message Helpers
 */

/*
 * LOCKING: must hold mod->lock
 */
static int ican3_new_send_msg(struct ican3_dev *mod, struct ican3_msg *msg)
{
	struct ican3_new_desc desc;
	void __iomem *desc_addr = mod->dpm + (mod->tx_num * sizeof(desc));

	/* switch to the fromhost mid queue, and read the buffer descriptor */
	ican3_set_page(mod, QUEUE_FROMHOST_MID);
	memcpy_fromio(&desc, desc_addr, sizeof(desc));

	if (!(desc.control & DESC_VALID)) {
		dev_dbg(mod->dev, "%s: no free buffers\n", __func__);
		return -ENOMEM;
	}

	/* switch to the data page, copy the data */
	ican3_set_page(mod, desc.pointer);
	memcpy_toio(mod->dpm, msg, sizeof(*msg));

	/* switch back to the descriptor, set the valid bit, write it back */
	ican3_set_page(mod, QUEUE_FROMHOST_MID);
	desc.control ^= DESC_VALID;
	memcpy_toio(desc_addr, &desc, sizeof(desc));

	/* update the tx number */
	mod->tx_num = (desc.control & DESC_WRAP) ? 0 : (mod->tx_num + 1);
	return 0;
}

/*
 * LOCKING: must hold mod->lock
 */
static int ican3_new_recv_msg(struct ican3_dev *mod, struct ican3_msg *msg)
{
	struct ican3_new_desc desc;
	void __iomem *desc_addr = mod->dpm + (mod->rx_num * sizeof(desc));

	/* switch to the tohost queue, and read the buffer descriptor */
	ican3_set_page(mod, QUEUE_TOHOST);
	memcpy_fromio(&desc, desc_addr, sizeof(desc));

	if (!(desc.control & DESC_VALID)) {
		dev_dbg(mod->dev, "%s: no buffers to recv\n", __func__);
		return -ENOMEM;
	}

	/* switch to the data page, copy the data */
	ican3_set_page(mod, desc.pointer);
	memcpy_fromio(msg, mod->dpm, sizeof(*msg));

	/* switch back to the descriptor, toggle the valid bit, write it back */
	ican3_set_page(mod, QUEUE_TOHOST);
	desc.control ^= DESC_VALID;
	memcpy_toio(desc_addr, &desc, sizeof(desc));

	/* update the rx number */
	mod->rx_num = (desc.control & DESC_WRAP) ? 0 : (mod->rx_num + 1);
	return 0;
}

/*
 * Message Send / Recv Helpers
 */

static int ican3_send_msg(struct ican3_dev *mod, struct ican3_msg *msg)
{
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&mod->lock, flags);

	if (mod->iftype == 0)
		ret = ican3_old_send_msg(mod, msg);
	else
		ret = ican3_new_send_msg(mod, msg);

	spin_unlock_irqrestore(&mod->lock, flags);
	return ret;
}

static int ican3_recv_msg(struct ican3_dev *mod, struct ican3_msg *msg)
{
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&mod->lock, flags);

	if (mod->iftype == 0)
		ret = ican3_old_recv_msg(mod, msg);
	else
		ret = ican3_new_recv_msg(mod, msg);

	spin_unlock_irqrestore(&mod->lock, flags);
	return ret;
}

/*
 * Quick Pre-constructed Messages
 */

static int ican3_msg_connect(struct ican3_dev *mod)
{
	struct ican3_msg msg;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_CONNECTI;
	msg.len = cpu_to_le16(0);

	return ican3_send_msg(mod, &msg);
}

static int ican3_msg_disconnect(struct ican3_dev *mod)
{
	struct ican3_msg msg;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_DISCONNECT;
	msg.len = cpu_to_le16(0);

	return ican3_send_msg(mod, &msg);
}

static int ican3_msg_newhostif(struct ican3_dev *mod)
{
	struct ican3_msg msg;
	int ret;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_NEWHOSTIF;
	msg.len = cpu_to_le16(0);

	/* If we're not using the old interface, switching seems bogus */
	WARN_ON(mod->iftype != 0);

	ret = ican3_send_msg(mod, &msg);
	if (ret)
		return ret;

	/* mark the module as using the new host interface */
	mod->iftype = 1;
	return 0;
}

static int ican3_msg_fasthostif(struct ican3_dev *mod)
{
	struct ican3_msg msg;
	unsigned int addr;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_INITFDPMQUEUE;
	msg.len = cpu_to_le16(8);

	/* write the tohost queue start address */
	addr = DPM_PAGE_ADDR(mod->fastrx_start);
	msg.data[0] = addr & 0xff;
	msg.data[1] = (addr >> 8) & 0xff;
	msg.data[2] = (addr >> 16) & 0xff;
	msg.data[3] = (addr >> 24) & 0xff;

	/* write the fromhost queue start address */
	addr = DPM_PAGE_ADDR(mod->fasttx_start);
	msg.data[4] = addr & 0xff;
	msg.data[5] = (addr >> 8) & 0xff;
	msg.data[6] = (addr >> 16) & 0xff;
	msg.data[7] = (addr >> 24) & 0xff;

	/* If we're not using the new interface yet, we cannot do this */
	WARN_ON(mod->iftype != 1);

	return ican3_send_msg(mod, &msg);
}

/*
 * Setup the CAN filter to either accept or reject all
 * messages from the CAN bus.
 */
static int ican3_set_id_filter(struct ican3_dev *mod, bool accept)
{
	struct ican3_msg msg;
	int ret;

	/* Standard Frame Format */
	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_SETAFILMASK;
	msg.len = cpu_to_le16(5);
	msg.data[0] = 0x00; /* IDLo LSB */
	msg.data[1] = 0x00; /* IDLo MSB */
	msg.data[2] = 0xff; /* IDHi LSB */
	msg.data[3] = 0x07; /* IDHi MSB */

	/* accept all frames for fast host if, or reject all frames */
	msg.data[4] = accept ? SETAFILMASK_FASTIF : SETAFILMASK_REJECT;

	ret = ican3_send_msg(mod, &msg);
	if (ret)
		return ret;

	/* Extended Frame Format */
	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_SETAFILMASK;
	msg.len = cpu_to_le16(13);
	msg.data[0] = 0;    /* MUX = 0 */
	msg.data[1] = 0x00; /* IDLo LSB */
	msg.data[2] = 0x00;
	msg.data[3] = 0x00;
	msg.data[4] = 0x20; /* IDLo MSB */
	msg.data[5] = 0xff; /* IDHi LSB */
	msg.data[6] = 0xff;
	msg.data[7] = 0xff;
	msg.data[8] = 0x3f; /* IDHi MSB */

	/* accept all frames for fast host if, or reject all frames */
	msg.data[9] = accept ? SETAFILMASK_FASTIF : SETAFILMASK_REJECT;

	return ican3_send_msg(mod, &msg);
}

/*
 * Bring the CAN bus online or offline
 */
static int ican3_set_bus_state(struct ican3_dev *mod, bool on)
{
	struct ican3_msg msg;

	memset(&msg, 0, sizeof(msg));
	msg.spec = on ? MSG_CONREQ : MSG_COFFREQ;
	msg.len = cpu_to_le16(0);

	return ican3_send_msg(mod, &msg);
}

static int ican3_set_termination(struct ican3_dev *mod, bool on)
{
	struct ican3_msg msg;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_HWCONF;
	msg.len = cpu_to_le16(2);
	msg.data[0] = 0x00;
	msg.data[1] = on ? HWCONF_TERMINATE_ON : HWCONF_TERMINATE_OFF;

	return ican3_send_msg(mod, &msg);
}

static int ican3_send_inquiry(struct ican3_dev *mod, u8 subspec)
{
	struct ican3_msg msg;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_INQUIRY;
	msg.len = cpu_to_le16(2);
	msg.data[0] = subspec;
	msg.data[1] = 0x00;

	return ican3_send_msg(mod, &msg);
}

static int ican3_set_buserror(struct ican3_dev *mod, u8 quota)
{
	struct ican3_msg msg;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_CCONFREQ;
	msg.len = cpu_to_le16(2);
	msg.data[0] = 0x00;
	msg.data[1] = quota;

	return ican3_send_msg(mod, &msg);
}

/*
 * ICAN3 to Linux CAN Frame Conversion
 */

static void ican3_to_can_frame(struct ican3_dev *mod,
			       struct ican3_fast_desc *desc,
			       struct can_frame *cf)
{
	if ((desc->command & ICAN3_CAN_TYPE_MASK) == ICAN3_CAN_TYPE_SFF) {
		if (desc->data[1] & ICAN3_SFF_RTR)
			cf->can_id |= CAN_RTR_FLAG;

		cf->can_id |= desc->data[0] << 3;
		cf->can_id |= (desc->data[1] & 0xe0) >> 5;
		cf->can_dlc = get_can_dlc(desc->data[1] & ICAN3_CAN_DLC_MASK);
		memcpy(cf->data, &desc->data[2], cf->can_dlc);
	} else {
		cf->can_dlc = get_can_dlc(desc->data[0] & ICAN3_CAN_DLC_MASK);
		if (desc->data[0] & ICAN3_EFF_RTR)
			cf->can_id |= CAN_RTR_FLAG;

		if (desc->data[0] & ICAN3_EFF) {
			cf->can_id |= CAN_EFF_FLAG;
			cf->can_id |= desc->data[2] << 21; /* 28-21 */
			cf->can_id |= desc->data[3] << 13; /* 20-13 */
			cf->can_id |= desc->data[4] << 5;  /* 12-5  */
			cf->can_id |= (desc->data[5] & 0xf8) >> 3;
		} else {
			cf->can_id |= desc->data[2] << 3;  /* 10-3  */
			cf->can_id |= desc->data[3] >> 5;  /* 2-0   */
		}

		memcpy(cf->data, &desc->data[6], cf->can_dlc);
	}
}

static void can_frame_to_ican3(struct ican3_dev *mod,
			       struct can_frame *cf,
			       struct ican3_fast_desc *desc)
{
	/* clear out any stale data in the descriptor */
	memset(desc->data, 0, sizeof(desc->data));

	/* we always use the extended format, with the ECHO flag set */
	desc->command = ICAN3_CAN_TYPE_EFF;
	desc->data[0] |= cf->can_dlc;
	desc->data[1] |= ICAN3_ECHO;

	/* support single transmission (no retries) mode */
	if (mod->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
		desc->data[1] |= ICAN3_SNGL;

	if (cf->can_id & CAN_RTR_FLAG)
		desc->data[0] |= ICAN3_EFF_RTR;

	/* pack the id into the correct places */
	if (cf->can_id & CAN_EFF_FLAG) {
		desc->data[0] |= ICAN3_EFF;
		desc->data[2] = (cf->can_id & 0x1fe00000) >> 21; /* 28-21 */
		desc->data[3] = (cf->can_id & 0x001fe000) >> 13; /* 20-13 */
		desc->data[4] = (cf->can_id & 0x00001fe0) >> 5;  /* 12-5  */
		desc->data[5] = (cf->can_id & 0x0000001f) << 3;  /* 4-0   */
	} else {
		desc->data[2] = (cf->can_id & 0x7F8) >> 3; /* bits 10-3 */
		desc->data[3] = (cf->can_id & 0x007) << 5; /* bits 2-0  */
	}

	/* copy the data bits into the descriptor */
	memcpy(&desc->data[6], cf->data, cf->can_dlc);
}

/*
 * Interrupt Handling
 */

/*
 * Handle an ID + Version message response from the firmware. We never generate
 * this message in production code, but it is very useful when debugging to be
 * able to display this message.
 */
static void ican3_handle_idvers(struct ican3_dev *mod, struct ican3_msg *msg)
{
	dev_dbg(mod->dev, "IDVERS response: %s\n", msg->data);
}

static void ican3_handle_msglost(struct ican3_dev *mod, struct ican3_msg *msg)
{
	struct net_device *dev = mod->ndev;
	struct net_device_stats *stats = &dev->stats;
	struct can_frame *cf;
	struct sk_buff *skb;

	/*
	 * Report that communication messages with the microcontroller firmware
	 * are being lost. These are never CAN frames, so we do not generate an
	 * error frame for userspace
	 */
	if (msg->spec == MSG_MSGLOST) {
		dev_err(mod->dev, "lost %d control messages\n", msg->data[0]);
		return;
	}

	/*
	 * Oops, this indicates that we have lost messages in the fast queue,
	 * which are exclusively CAN messages. Our driver isn't reading CAN
	 * frames fast enough.
	 *
	 * We'll pretend that the SJA1000 told us that it ran out of buffer
	 * space, because there is not a better message for this.
	 */
	skb = alloc_can_err_skb(dev, &cf);
	if (skb) {
		cf->can_id |= CAN_ERR_CRTL;
		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
		stats->rx_over_errors++;
		stats->rx_errors++;
		netif_rx(skb);
	}
}

/*
 * Handle CAN Event Indication Messages from the firmware
 *
 * The ICAN3 firmware provides the values of some SJA1000 registers when it
 * generates this message. The code below is largely copied from the
 * drivers/net/can/sja1000/sja1000.c file, and adapted as necessary
 */
static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
{
	struct net_device *dev = mod->ndev;
	struct net_device_stats *stats = &dev->stats;
	enum can_state state = mod->can.state;
	u8 isrc, ecc, status, rxerr, txerr;
	struct can_frame *cf;
	struct sk_buff *skb;

	/* we can only handle the SJA1000 part */
	if (msg->data[1] != CEVTIND_CHIP_SJA1000) {
		dev_err(mod->dev, "unable to handle errors on non-SJA1000\n");
		return -ENODEV;
	}

	/* check the message length for sanity */
	if (le16_to_cpu(msg->len) < 6) {
		dev_err(mod->dev, "error message too short\n");
		return -EINVAL;
	}

	isrc = msg->data[0];
	ecc = msg->data[2];
	status = msg->data[3];
	rxerr = msg->data[4];
	txerr = msg->data[5];

	/*
	 * This hardware lacks any support other than bus error messages to
	 * determine if packet transmission has failed.
	 *
	 * When TX errors happen, one echo skb needs to be dropped from the
	 * front of the queue.
	 *
	 * A small bit of code is duplicated here and below, to avoid error
	 * skb allocation when it will just be freed immediately.
	 */
	if (isrc == CEVTIND_BEI) {
		int ret;
		dev_dbg(mod->dev, "bus error interrupt\n");

		/* TX error */
		if (!(ecc & ECC_DIR)) {
			kfree_skb(skb_dequeue(&mod->echoq));
			stats->tx_errors++;
		} else {
			stats->rx_errors++;
		}

		/*
		 * The controller automatically disables bus-error interrupts
		 * and therefore we must re-enable them.
		 */
		ret = ican3_set_buserror(mod, 1);
		if (ret) {
			dev_err(mod->dev, "unable to re-enable bus-error\n");
			return ret;
		}

		/* bus error reporting is off, return immediately */
		if (!(mod->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
			return 0;
	}

	skb = alloc_can_err_skb(dev, &cf);
	if (skb == NULL)
		return -ENOMEM;

	/* data overrun interrupt */
	if (isrc == CEVTIND_DOI || isrc == CEVTIND_LOST) {
		dev_dbg(mod->dev, "data overrun interrupt\n");
		cf->can_id |= CAN_ERR_CRTL;
		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
		stats->rx_over_errors++;
		stats->rx_errors++;
	}

	/* error warning + passive interrupt */
	if (isrc == CEVTIND_EI) {
		dev_dbg(mod->dev, "error warning + passive interrupt\n");
		if (status & SR_BS) {
			state = CAN_STATE_BUS_OFF;
			cf->can_id |= CAN_ERR_BUSOFF;
			can_bus_off(dev);
		} else if (status & SR_ES) {
			if (rxerr >= 128 || txerr >= 128)
				state = CAN_STATE_ERROR_PASSIVE;
			else
				state = CAN_STATE_ERROR_WARNING;
		} else {
			state = CAN_STATE_ERROR_ACTIVE;
		}
	}

	/* bus error interrupt */
	if (isrc == CEVTIND_BEI) {
		mod->can.can_stats.bus_error++;
		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;

		switch (ecc & ECC_MASK) {
		case ECC_BIT:
			cf->data[2] |= CAN_ERR_PROT_BIT;
			break;
		case ECC_FORM:
			cf->data[2] |= CAN_ERR_PROT_FORM;
			break;
		case ECC_STUFF:
			cf->data[2] |= CAN_ERR_PROT_STUFF;
			break;
		default:
			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
			cf->data[3] = ecc & ECC_SEG;
			break;
		}

		if (!(ecc & ECC_DIR))
			cf->data[2] |= CAN_ERR_PROT_TX;

		cf->data[6] = txerr;
		cf->data[7] = rxerr;
	}

	if (state != mod->can.state && (state == CAN_STATE_ERROR_WARNING ||
					state == CAN_STATE_ERROR_PASSIVE)) {
		cf->can_id |= CAN_ERR_CRTL;
		if (state == CAN_STATE_ERROR_WARNING) {
			mod->can.can_stats.error_warning++;
			cf->data[1] = (txerr > rxerr) ?
				CAN_ERR_CRTL_TX_WARNING :
				CAN_ERR_CRTL_RX_WARNING;
		} else {
			mod->can.can_stats.error_passive++;
			cf->data[1] = (txerr > rxerr) ?
				CAN_ERR_CRTL_TX_PASSIVE :
				CAN_ERR_CRTL_RX_PASSIVE;
		}

		cf->data[6] = txerr;
		cf->data[7] = rxerr;
	}

	mod->can.state = state;
	netif_rx(skb);
	return 0;
}

static void ican3_handle_inquiry(struct ican3_dev *mod, struct ican3_msg *msg)
{
	switch (msg->data[0]) {
	case INQUIRY_STATUS:
	case INQUIRY_EXTENDED:
		mod->bec.rxerr = msg->data[5];
		mod->bec.txerr = msg->data[6];
		complete(&mod->buserror_comp);
		break;
	case INQUIRY_TERMINATION:
		mod->termination_enabled = msg->data[6] & HWCONF_TERMINATE_ON;
		complete(&mod->termination_comp);
		break;
	default:
		dev_err(mod->dev, "received an unknown inquiry response\n");
		break;
	}
}

static void ican3_handle_unknown_message(struct ican3_dev *mod,
					struct ican3_msg *msg)
{
	dev_warn(mod->dev, "received unknown message: spec 0x%.2x length %d\n",
			   msg->spec, le16_to_cpu(msg->len));
}

/*
 * Handle a control message from the firmware
 */
static void ican3_handle_message(struct ican3_dev *mod, struct ican3_msg *msg)
{
	dev_dbg(mod->dev, "%s: modno %d spec 0x%.2x len %d bytes\n", __func__,
			   mod->num, msg->spec, le16_to_cpu(msg->len));

	switch (msg->spec) {
	case MSG_IDVERS:
		ican3_handle_idvers(mod, msg);
		break;
	case MSG_MSGLOST:
	case MSG_FMSGLOST:
		ican3_handle_msglost(mod, msg);
		break;
	case MSG_CEVTIND:
		ican3_handle_cevtind(mod, msg);
		break;
	case MSG_INQUIRY:
		ican3_handle_inquiry(mod, msg);
		break;
	default:
		ican3_handle_unknown_message(mod, msg);
		break;
	}
}

/*
 * The ican3 needs to store all echo skbs, and therefore cannot
 * use the generic infrastructure for this.
 */
static void ican3_put_echo_skb(struct ican3_dev *mod, struct sk_buff *skb)
{
	struct sock *srcsk = skb->sk;

	if (atomic_read(&skb->users) != 1) {
		struct sk_buff *old_skb = skb;

		skb = skb_clone(old_skb, GFP_ATOMIC);
		kfree_skb(old_skb);
		if (!skb)
			return;
	} else {
		skb_orphan(skb);
	}

	skb->sk = srcsk;

	/* save this skb for tx interrupt echo handling */
	skb_queue_tail(&mod->echoq, skb);
}

static unsigned int ican3_get_echo_skb(struct ican3_dev *mod)
{
	struct sk_buff *skb = skb_dequeue(&mod->echoq);
	struct can_frame *cf;
	u8 dlc;

	/* this should never trigger unless there is a driver bug */
	if (!skb) {
		netdev_err(mod->ndev, "BUG: echo skb not occupied\n");
		return 0;
	}

	cf = (struct can_frame *)skb->data;
	dlc = cf->can_dlc;

	/* check flag whether this packet has to be looped back */
	if (skb->pkt_type != PACKET_LOOPBACK) {
		kfree_skb(skb);
		return dlc;
	}

	skb->protocol = htons(ETH_P_CAN);
	skb->pkt_type = PACKET_BROADCAST;
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	skb->dev = mod->ndev;
	netif_receive_skb(skb);
	return dlc;
}

/*
 * Compare an skb with an existing echo skb
 *
 * This function will be used on devices which have a hardware loopback.
 * On these devices, this function can be used to compare a received skb
 * with the saved echo skbs so that the hardware echo skb can be dropped.
 *
 * Returns true if the skb's are identical, false otherwise.
 */
static bool ican3_echo_skb_matches(struct ican3_dev *mod, struct sk_buff *skb)
{
	struct can_frame *cf = (struct can_frame *)skb->data;
	struct sk_buff *echo_skb = skb_peek(&mod->echoq);
	struct can_frame *echo_cf;

	if (!echo_skb)
		return false;

	echo_cf = (struct can_frame *)echo_skb->data;
	if (cf->can_id != echo_cf->can_id)
		return false;

	if (cf->can_dlc != echo_cf->can_dlc)
		return false;

	return memcmp(cf->data, echo_cf->data, cf->can_dlc) == 0;
}

/*
 * Check that there is room in the TX ring to transmit another skb
 *
 * LOCKING: must hold mod->lock
 */
static bool ican3_txok(struct ican3_dev *mod)
{
	struct ican3_fast_desc __iomem *desc;
	u8 control;

	/* check that we have echo queue space */
	if (skb_queue_len(&mod->echoq) >= ICAN3_TX_BUFFERS)
		return false;

	/* copy the control bits of the descriptor */
	ican3_set_page(mod, mod->fasttx_start + (mod->fasttx_num / 16));
	desc = mod->dpm + ((mod->fasttx_num % 16) * sizeof(*desc));
	control = ioread8(&desc->control);

	/* if the control bits are not valid, then we have no more space */
	if (!(control & DESC_VALID))
		return false;

	return true;
}

/*
 * Receive one CAN frame from the hardware
 *
 * CONTEXT: must be called from user context
 */
static int ican3_recv_skb(struct ican3_dev *mod)
{
	struct net_device *ndev = mod->ndev;
	struct net_device_stats *stats = &ndev->stats;
	struct ican3_fast_desc desc;
	void __iomem *desc_addr;
	struct can_frame *cf;
	struct sk_buff *skb;
	unsigned long flags;

	spin_lock_irqsave(&mod->lock, flags);

	/* copy the whole descriptor */
	ican3_set_page(mod, mod->fastrx_start + (mod->fastrx_num / 16));
	desc_addr = mod->dpm + ((mod->fastrx_num % 16) * sizeof(desc));
	memcpy_fromio(&desc, desc_addr, sizeof(desc));

	spin_unlock_irqrestore(&mod->lock, flags);

	/* check that we actually have a CAN frame */
	if (!(desc.control & DESC_VALID))
		return -ENOBUFS;

	/* allocate an skb */
	skb = alloc_can_skb(ndev, &cf);
	if (unlikely(skb == NULL)) {
		stats->rx_dropped++;
		goto err_noalloc;
	}

	/* convert the ICAN3 frame into Linux CAN format */
	ican3_to_can_frame(mod, &desc, cf);

	/*
	 * If this is an ECHO frame received from the hardware loopback
	 * feature, use the skb saved in the ECHO stack instead. This allows
	 * the Linux CAN core to support CAN_RAW_RECV_OWN_MSGS correctly.
	 *
	 * Since this is a confirmation of a successfully transmitted packet
	 * sent from this host, update the transmit statistics.
	 *
	 * Also, the netdevice queue needs to be allowed to send packets again.
	 */
	if (ican3_echo_skb_matches(mod, skb)) {
		stats->tx_packets++;
		stats->tx_bytes += ican3_get_echo_skb(mod);
		kfree_skb(skb);
		goto err_noalloc;
	}

	/* update statistics, receive the skb */
	stats->rx_packets++;
	stats->rx_bytes += cf->can_dlc;
	netif_receive_skb(skb);

err_noalloc:
	/* toggle the valid bit and return the descriptor to the ring */
	desc.control ^= DESC_VALID;

	spin_lock_irqsave(&mod->lock, flags);

	ican3_set_page(mod, mod->fastrx_start + (mod->fastrx_num / 16));
	memcpy_toio(desc_addr, &desc, 1);

	/* update the next buffer pointer */
	mod->fastrx_num = (desc.control & DESC_WRAP) ? 0
						     : (mod->fastrx_num + 1);

	/* there are still more buffers to process */
	spin_unlock_irqrestore(&mod->lock, flags);
	return 0;
}

static int ican3_napi(struct napi_struct *napi, int budget)
{
	struct ican3_dev *mod = container_of(napi, struct ican3_dev, napi);
	unsigned long flags;
	int received = 0;
	int ret;

	/* process all communication messages */
	while (true) {
		struct ican3_msg msg;
		ret = ican3_recv_msg(mod, &msg);
		if (ret)
			break;

		ican3_handle_message(mod, &msg);
	}

	/* process all CAN frames from the fast interface */
	while (received < budget) {
		ret = ican3_recv_skb(mod);
		if (ret)
			break;

		received++;
	}

	/* We have processed all packets that the adapter had, but it
	 * was less than our budget, stop polling */
	if (received < budget)
		napi_complete(napi);

	spin_lock_irqsave(&mod->lock, flags);

	/* Wake up the transmit queue if necessary */
	if (netif_queue_stopped(mod->ndev) && ican3_txok(mod))
		netif_wake_queue(mod->ndev);

	spin_unlock_irqrestore(&mod->lock, flags);

	/* re-enable interrupt generation */
	iowrite8(1 << mod->num, &mod->ctrl->int_enable);
	return received;
}

static irqreturn_t ican3_irq(int irq, void *dev_id)
{
	struct ican3_dev *mod = dev_id;
	u8 stat;

	/*
	 * The interrupt status register on this device reports interrupts
	 * as zeroes instead of using ones like most other devices
	 */
	stat = ioread8(&mod->ctrl->int_disable) & (1 << mod->num);
	if (stat == (1 << mod->num))
		return IRQ_NONE;

	/* clear the MODULbus interrupt from the microcontroller */
	ioread8(&mod->dpmctrl->interrupt);

	/* disable interrupt generation, schedule the NAPI poller */
	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
	napi_schedule(&mod->napi);
	return IRQ_HANDLED;
}

/*
 * Firmware reset, startup, and shutdown
 */

/*
 * Reset an ICAN module to its power-on state
 *
 * CONTEXT: no network device registered
 */
static int ican3_reset_module(struct ican3_dev *mod)
{
	unsigned long start;
	u8 runold, runnew;

	/* disable interrupts so no more work is scheduled */
	iowrite8(1 << mod->num, &mod->ctrl->int_disable);

	/* the first unallocated page in the DPM is #9 */
	mod->free_page = DPM_FREE_START;

	ican3_set_page(mod, QUEUE_OLD_CONTROL);
	runold = ioread8(mod->dpm + TARGET_RUNNING);

	/* reset the module */
	iowrite8(0x00, &mod->dpmctrl->hwreset);

	/* wait until the module has finished resetting and is running */
	start = jiffies;
	do {
		ican3_set_page(mod, QUEUE_OLD_CONTROL);
		runnew = ioread8(mod->dpm + TARGET_RUNNING);
		if (runnew == (runold ^ 0xff))
			return 0;

		msleep(10);
	} while (time_before(jiffies, start + HZ / 4));

	dev_err(mod->dev, "failed to reset CAN module\n");
	return -ETIMEDOUT;
}

static void ican3_shutdown_module(struct ican3_dev *mod)
{
	ican3_msg_disconnect(mod);
	ican3_reset_module(mod);
}

/*
 * Startup an ICAN module, bringing it into fast mode
 */
static int ican3_startup_module(struct ican3_dev *mod)
{
	int ret;

	ret = ican3_reset_module(mod);
	if (ret) {
		dev_err(mod->dev, "unable to reset module\n");
		return ret;
	}

	/* re-enable interrupts so we can send messages */
	iowrite8(1 << mod->num, &mod->ctrl->int_enable);

	ret = ican3_msg_connect(mod);
	if (ret) {
		dev_err(mod->dev, "unable to connect to module\n");
		return ret;
	}

	ican3_init_new_host_interface(mod);
	ret = ican3_msg_newhostif(mod);
	if (ret) {
		dev_err(mod->dev, "unable to switch to new-style interface\n");
		return ret;
	}

	/* default to "termination on" */
	ret = ican3_set_termination(mod, true);
	if (ret) {
		dev_err(mod->dev, "unable to enable termination\n");
		return ret;
	}

	/* default to "bus errors enabled" */
	ret = ican3_set_buserror(mod, 1);
	if (ret) {
		dev_err(mod->dev, "unable to set bus-error\n");
		return ret;
	}

	ican3_init_fast_host_interface(mod);
	ret = ican3_msg_fasthostif(mod);
	if (ret) {
		dev_err(mod->dev, "unable to switch to fast host interface\n");
		return ret;
	}

	ret = ican3_set_id_filter(mod, true);
	if (ret) {
		dev_err(mod->dev, "unable to set acceptance filter\n");
		return ret;
	}

	return 0;
}

/*
 * CAN Network Device
 */

static int ican3_open(struct net_device *ndev)
{
	struct ican3_dev *mod = netdev_priv(ndev);
	int ret;

	/* open the CAN layer */
	ret = open_candev(ndev);
	if (ret) {
		dev_err(mod->dev, "unable to start CAN layer\n");
		return ret;
	}

	/* bring the bus online */
	ret = ican3_set_bus_state(mod, true);
	if (ret) {
		dev_err(mod->dev, "unable to set bus-on\n");
		close_candev(ndev);
		return ret;
	}

	/* start up the network device */
	mod->can.state = CAN_STATE_ERROR_ACTIVE;
	netif_start_queue(ndev);

	return 0;
}

static int ican3_stop(struct net_device *ndev)
{
	struct ican3_dev *mod = netdev_priv(ndev);
	int ret;

	/* stop the network device xmit routine */
	netif_stop_queue(ndev);
	mod->can.state = CAN_STATE_STOPPED;

	/* bring the bus offline, stop receiving packets */
	ret = ican3_set_bus_state(mod, false);
	if (ret) {
		dev_err(mod->dev, "unable to set bus-off\n");
		return ret;
	}

	/* drop all outstanding echo skbs */
	skb_queue_purge(&mod->echoq);

	/* close the CAN layer */
	close_candev(ndev);
	return 0;
}

static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
{
	struct ican3_dev *mod = netdev_priv(ndev);
	struct can_frame *cf = (struct can_frame *)skb->data;
	struct ican3_fast_desc desc;
	void __iomem *desc_addr;
	unsigned long flags;

	if (can_dropped_invalid_skb(ndev, skb))
		return NETDEV_TX_OK;

	spin_lock_irqsave(&mod->lock, flags);

	/* check that we can actually transmit */
	if (!ican3_txok(mod)) {
		dev_err(mod->dev, "BUG: no free descriptors\n");
		spin_unlock_irqrestore(&mod->lock, flags);
		return NETDEV_TX_BUSY;
	}

	/* copy the control bits of the descriptor */
	ican3_set_page(mod, mod->fasttx_start + (mod->fasttx_num / 16));
	desc_addr = mod->dpm + ((mod->fasttx_num % 16) * sizeof(desc));
	memset(&desc, 0, sizeof(desc));
	memcpy_fromio(&desc, desc_addr, 1);

	/* convert the Linux CAN frame into ICAN3 format */
	can_frame_to_ican3(mod, cf, &desc);

	/*
	 * This hardware doesn't have TX-done notifications, so we'll try and
	 * emulate it the best we can using ECHO skbs. Add the skb to the ECHO
	 * stack. Upon packet reception, check if the ECHO skb and received
	 * skb match, and use that to wake the queue.
	 */
	ican3_put_echo_skb(mod, skb);

	/*
	 * the programming manual says that you must set the IVALID bit, then
	 * interrupt, then set the valid bit. Quite weird, but it seems to be
	 * required for this to work
	 */
	desc.control |= DESC_IVALID;
	memcpy_toio(desc_addr, &desc, sizeof(desc));

	/* generate a MODULbus interrupt to the microcontroller */
	iowrite8(0x01, &mod->dpmctrl->interrupt);

	desc.control ^= DESC_VALID;
	memcpy_toio(desc_addr, &desc, sizeof(desc));

	/* update the next buffer pointer */
	mod->fasttx_num = (desc.control & DESC_WRAP) ? 0
						     : (mod->fasttx_num + 1);

	/* if there is no free descriptor space, stop the transmit queue */
	if (!ican3_txok(mod))
		netif_stop_queue(ndev);

	spin_unlock_irqrestore(&mod->lock, flags);
	return NETDEV_TX_OK;
}

static const struct net_device_ops ican3_netdev_ops = {
	.ndo_open	= ican3_open,
	.ndo_stop	= ican3_stop,
	.ndo_start_xmit	= ican3_xmit,
};

/*
 * Low-level CAN Device
 */

/* This structure was stolen from drivers/net/can/sja1000/sja1000.c */
static const struct can_bittiming_const ican3_bittiming_const = {
	.name = DRV_NAME,
	.tseg1_min = 1,
	.tseg1_max = 16,
	.tseg2_min = 1,
	.tseg2_max = 8,
	.sjw_max = 4,
	.brp_min = 1,
	.brp_max = 64,
	.brp_inc = 1,
};

/*
 * This routine was stolen from drivers/net/can/sja1000/sja1000.c
 *
 * The bittiming register command for the ICAN3 just sets the bit timing
 * registers on the SJA1000 chip directly
 */
static int ican3_set_bittiming(struct net_device *ndev)
{
	struct ican3_dev *mod = netdev_priv(ndev);
	struct can_bittiming *bt = &mod->can.bittiming;
	struct ican3_msg msg;
	u8 btr0, btr1;

	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
		(((bt->phase_seg2 - 1) & 0x7) << 4);
	if (mod->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
		btr1 |= 0x80;

	memset(&msg, 0, sizeof(msg));
	msg.spec = MSG_CBTRREQ;
	msg.len = cpu_to_le16(4);
	msg.data[0] = 0x00;
	msg.data[1] = 0x00;
	msg.data[2] = btr0;
	msg.data[3] = btr1;

	return ican3_send_msg(mod, &msg);
}

static int ican3_set_mode(struct net_device *ndev, enum can_mode mode)
{
	struct ican3_dev *mod = netdev_priv(ndev);
	int ret;

	if (mode != CAN_MODE_START)
		return -ENOTSUPP;

	/* bring the bus online */
	ret = ican3_set_bus_state(mod, true);
	if (ret) {
		dev_err(mod->dev, "unable to set bus-on\n");
		return ret;
	}

	/* start up the network device */
	mod->can.state = CAN_STATE_ERROR_ACTIVE;

	if (netif_queue_stopped(ndev))
		netif_wake_queue(ndev);

	return 0;
}

static int ican3_get_berr_counter(const struct net_device *ndev,
				  struct can_berr_counter *bec)
{
	struct ican3_dev *mod = netdev_priv(ndev);
	int ret;

	ret = ican3_send_inquiry(mod, INQUIRY_STATUS);
	if (ret)
		return ret;

	ret = wait_for_completion_timeout(&mod->buserror_comp, HZ);
	if (ret == 0) {
		dev_info(mod->dev, "%s timed out\n", __func__);
		return -ETIMEDOUT;
	}

	bec->rxerr = mod->bec.rxerr;
	bec->txerr = mod->bec.txerr;
	return 0;
}

/*
 * Sysfs Attributes
 */

static ssize_t ican3_sysfs_show_term(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	struct ican3_dev *mod = netdev_priv(to_net_dev(dev));
	int ret;

	ret = ican3_send_inquiry(mod, INQUIRY_TERMINATION);
	if (ret)
		return ret;

	ret = wait_for_completion_timeout(&mod->termination_comp, HZ);
	if (ret == 0) {
		dev_info(mod->dev, "%s timed out\n", __func__);
		return -ETIMEDOUT;
	}

	return snprintf(buf, PAGE_SIZE, "%u\n", mod->termination_enabled);
}

static ssize_t ican3_sysfs_set_term(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{
	struct ican3_dev *mod = netdev_priv(to_net_dev(dev));
	unsigned long enable;
	int ret;

	if (kstrtoul(buf, 0, &enable))
		return -EINVAL;

	ret = ican3_set_termination(mod, enable);
	if (ret)
		return ret;

	return count;
}

static DEVICE_ATTR(termination, S_IWUSR | S_IRUGO, ican3_sysfs_show_term,
						   ican3_sysfs_set_term);

static struct attribute *ican3_sysfs_attrs[] = {
	&dev_attr_termination.attr,
	NULL,
};

static struct attribute_group ican3_sysfs_attr_group = {
	.attrs = ican3_sysfs_attrs,
};

/*
 * PCI Subsystem
 */

static int ican3_probe(struct platform_device *pdev)
{
	struct janz_platform_data *pdata;
	struct net_device *ndev;
	struct ican3_dev *mod;
	struct resource *res;
	struct device *dev;
	int ret;

	pdata = pdev->dev.platform_data;
	if (!pdata)
		return -ENXIO;

	dev_dbg(&pdev->dev, "probe: module number %d\n", pdata->modno);

	/* save the struct device for printing */
	dev = &pdev->dev;

	/* allocate the CAN device and private data */
	ndev = alloc_candev(sizeof(*mod), 0);
	if (!ndev) {
		dev_err(dev, "unable to allocate CANdev\n");
		ret = -ENOMEM;
		goto out_return;
	}

	platform_set_drvdata(pdev, ndev);
	mod = netdev_priv(ndev);
	mod->ndev = ndev;
	mod->dev = &pdev->dev;
	mod->num = pdata->modno;
	netif_napi_add(ndev, &mod->napi, ican3_napi, ICAN3_RX_BUFFERS);
	skb_queue_head_init(&mod->echoq);
	spin_lock_init(&mod->lock);
	init_completion(&mod->termination_comp);
	init_completion(&mod->buserror_comp);

	/* setup device-specific sysfs attributes */
	ndev->sysfs_groups[0] = &ican3_sysfs_attr_group;

	/* the first unallocated page in the DPM is 9 */
	mod->free_page = DPM_FREE_START;

	ndev->netdev_ops = &ican3_netdev_ops;
	ndev->flags |= IFF_ECHO;
	SET_NETDEV_DEV(ndev, &pdev->dev);

	mod->can.clock.freq = ICAN3_CAN_CLOCK;
	mod->can.bittiming_const = &ican3_bittiming_const;
	mod->can.do_set_bittiming = ican3_set_bittiming;
	mod->can.do_set_mode = ican3_set_mode;
	mod->can.do_get_berr_counter = ican3_get_berr_counter;
	mod->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES
				    | CAN_CTRLMODE_BERR_REPORTING
				    | CAN_CTRLMODE_ONE_SHOT;

	/* find our IRQ number */
	mod->irq = platform_get_irq(pdev, 0);
	if (mod->irq < 0) {
		dev_err(dev, "IRQ line not found\n");
		ret = -ENODEV;
		goto out_free_ndev;
	}

	ndev->irq = mod->irq;

	/* get access to the MODULbus registers for this module */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev, "MODULbus registers not found\n");
		ret = -ENODEV;
		goto out_free_ndev;
	}

	mod->dpm = ioremap(res->start, resource_size(res));
	if (!mod->dpm) {
		dev_err(dev, "MODULbus registers not ioremap\n");
		ret = -ENOMEM;
		goto out_free_ndev;
	}

	mod->dpmctrl = mod->dpm + DPM_PAGE_SIZE;

	/* get access to the control registers for this module */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (!res) {
		dev_err(dev, "CONTROL registers not found\n");
		ret = -ENODEV;
		goto out_iounmap_dpm;
	}

	mod->ctrl = ioremap(res->start, resource_size(res));
	if (!mod->ctrl) {
		dev_err(dev, "CONTROL registers not ioremap\n");
		ret = -ENOMEM;
		goto out_iounmap_dpm;
	}

	/* disable our IRQ, then hookup the IRQ handler */
	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
	ret = request_irq(mod->irq, ican3_irq, IRQF_SHARED, DRV_NAME, mod);
	if (ret) {
		dev_err(dev, "unable to request IRQ\n");
		goto out_iounmap_ctrl;
	}

	/* reset and initialize the CAN controller into fast mode */
	napi_enable(&mod->napi);
	ret = ican3_startup_module(mod);
	if (ret) {
		dev_err(dev, "%s: unable to start CANdev\n", __func__);
		goto out_free_irq;
	}

	/* register with the Linux CAN layer */
	ret = register_candev(ndev);
	if (ret) {
		dev_err(dev, "%s: unable to register CANdev\n", __func__);
		goto out_free_irq;
	}

	dev_info(dev, "module %d: registered CAN device\n", pdata->modno);
	return 0;

out_free_irq:
	napi_disable(&mod->napi);
	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
	free_irq(mod->irq, mod);
out_iounmap_ctrl:
	iounmap(mod->ctrl);
out_iounmap_dpm:
	iounmap(mod->dpm);
out_free_ndev:
	free_candev(ndev);
out_return:
	return ret;
}

static int ican3_remove(struct platform_device *pdev)
{
	struct net_device *ndev = platform_get_drvdata(pdev);
	struct ican3_dev *mod = netdev_priv(ndev);

	/* unregister the netdevice, stop interrupts */
	unregister_netdev(ndev);
	napi_disable(&mod->napi);
	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
	free_irq(mod->irq, mod);

	/* put the module into reset */
	ican3_shutdown_module(mod);

	/* unmap all registers */
	iounmap(mod->ctrl);
	iounmap(mod->dpm);

	free_candev(ndev);

	return 0;
}

static struct platform_driver ican3_driver = {
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	},
	.probe		= ican3_probe,
	.remove		= ican3_remove,
};

module_platform_driver(ican3_driver);

MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("Janz MODULbus VMOD-ICAN3 Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:janz-ican3");