Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
   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
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
/* $Id: tpqic02.c,v 1.10 1997/01/26 07:13:20 davem Exp $
 *
 * Driver for tape drive support for Linux-i386
 *
 * Copyright (c) 1992--1996 by H. H. Bergman. All rights reserved.
 * Current e-mail address: hennus@cybercomm.nl
 *
 * Distribution of this program in executable form is only allowed if
 * all of the corresponding source files are made available through the same
 * medium at no extra cost.
 *
 * I will not accept any responsibility for damage caused directly or
 * indirectly by this program, or code derived from this program.
 *
 * Use this code at your own risk. Don't blame me if it destroys your data!
 * Make sure you have a backup before you try this code.
 *
 * If you make changes to my code and redistribute it in source or binary
 * form you must make it clear to even casual users of your code that you
 * have modified my code, clearly point out what the changes exactly are
 * (preferably in the form of a context diff file), how to undo your changes,
 * where the original can be obtained, and that complaints/requests about the
 * modified code should be directed to you instead of me.
 *
 * This driver was partially inspired by the 'wt' driver in the 386BSD
 * source distribution, which carries the following copyright notice:
 *
 *  Copyright (c) 1991 The Regents of the University of California.
 *  All rights reserved.
 *
 * You are not allowed to change this line nor the text above.
 *
 * 1996/10/10   Emerald changes
 *
 * 1996/05/21	Misc changes+merges+cleanups + I/O reservations
 *
 * 1996/05/20	Module support patches submitted by Brian McCauley.
 *
 * 1994/05/03	Initial attempt at Mountain support for the Mountain 7150.
 * Based on patches provided by Erik Jacobson. Still incomplete, I suppose.
 *
 * 1994/02/07	Archive changes & some cleanups by Eddy Olk.
 *
 * 1994/01/19	Speed measuring stuff moved from aperf.h to delay.h.
 *		BogoMips (tm) introduced by Linus.
 *
 * 1993/01/25	Kernel udelay. Eof fixups.
 * 
 * 1992/09/19	Some changes based on patches by Eddy Olk to support
 * 		Archive SC402/SC499R controller cards.
 *
 * 1992/05/27	First release.
 *
 * 1992/05/26	Initial version. Copyright H. H. Bergman 1992
 */

/* After the legalese, now the important bits:
 * 
 * This is a driver for the Wangtek 5150 tape drive with 
 * a QIC-02 controller for ISA-PC type computers.
 * Hopefully it will work with other QIC-02 tape drives as well.
 *
 * Make sure your setup matches the configuration parameters.
 * Also, be careful to avoid IO conflicts with other devices!
 */


/*
#define TDEBUG
*/

#define REALLY_SLOW_IO		/* it sure is ... */

#include <linux/module.h>

#include <linux/config.h>

#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/mtio.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/tpqic02.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/init.h>
 
#include <asm/dma.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/uaccess.h>

/* check existence of required configuration parameters */
#if !defined(QIC02_CMD_PORT) || !defined(QIC02_TAPE_IRQ) || !defined(QIC02_TAPE_DMA)
# error qic02_tape configuration error
#endif


#define TPQIC02_NAME	"tpqic02"

/* Linux outb() commands have (value,port) as parameters.
 * One might expect (port,value) instead, so beware!
 */

#ifdef CONFIG_QIC02_DYNCONF
/* This holds the dynamic configuration info for the interface
 * card+drive info if runtime configuration has been selected.
 */

static struct mtconfiginfo qic02_tape_dynconf = 	/* user settable */
    { 0, 0, BOGUS_IRQ, 0, 0, TPQD_DEFAULT_FLAGS, };
static struct qic02_ccb qic02_tape_ccb = { 0, };	/* private stuff */

#else

unsigned long qic02_tape_debug = TPQD_DEFAULT_FLAGS;

# if ((QIC02_TAPE_IFC!=WANGTEK) && (QIC02_TAPE_IFC!=ARCHIVE) && (QIC02_TAPE_IFC!=MOUNTAIN))
#  error No valid interface card specified
# endif
#endif /* CONFIG_QIC02_DYNCONF */

static volatile int ctlbits = 0;     /* control reg bits for tape interface */

static struct wait_queue *qic02_tape_transfer = NULL; /* sync rw with interrupts */

static volatile struct mtget ioctl_status;	/* current generic status */

static volatile struct tpstatus tperror;	/* last drive status */

static char rcs_revision[] = "$Revision: 1.10 $";
static char rcs_date[] = "$Date: 1997/01/26 07:13:20 $";

/* Flag bits for status and outstanding requests.
 * (Could all be put in one bit-field-struct.)
 * Some variables need `volatile' because they may be modified
 * by an interrupt.
 */
static volatile flag status_dead = YES;	/* device is legally dead until proven alive */
static 		flag status_zombie = YES; /* it's `zombie' until irq/dma allocated */

static volatile flag status_bytes_wr = NO;	/* write FM at close or not */
static volatile flag status_bytes_rd = NO;	/* (rd|wr) used for rewinding */

static volatile unsigned long status_cmd_pending = 0; /* cmd in progress */
static volatile flag status_expect_int = NO;	/* ready for interrupts */
static volatile flag status_timer_on = NO; 	/* using time-out */
static volatile int  status_error = 0;		/* int handler may detect error */
static volatile flag status_eof_detected = NO;	/* end of file */
static volatile flag status_eom_detected = NO;	/* end of recorded media */
static volatile flag status_eot_detected = NO;	/* end of tape */
static volatile flag doing_read = NO;
static volatile flag doing_write = NO;

static volatile unsigned long dma_bytes_todo;
static volatile unsigned long dma_bytes_done;
static volatile unsigned dma_mode = 0;		/* !=0 also means DMA in use */
static 		flag need_rewind = YES;

static kdev_t current_tape_dev;
static int extra_blocks_left = BLOCKS_BEYOND_EW;


/* return_*_eof:
 *	NO:	not at EOF,
 *	YES:	tell app EOF was reached (return 0).
 *
 * return_*_eof==YES && reported_*_eof==NO  ==>
 *	return current buffer, next time(s) return EOF.
 *
 * return_*_eof==YES && reported_*_eof==YES  ==>
 *	at EOF and application knows it, so we can
 *	move on to the next file.
 *
 */
static flag return_read_eof = NO;	/* set to signal app EOF was reached */
static flag return_write_eof = NO;
static flag reported_read_eof = NO;	/* set when we've done that */
static flag reported_write_eof = NO;


/* This is for doing `mt seek <blocknr>' */
static char seek_addr_buf[AR_SEEK_BUF_SIZE];


/* In write mode, we have to write a File Mark after the last block written, 
 * when the tape device is closed. Tape repositioning and reading in write
 * mode is allowed as long as no actual writing has been done. After writing
 * the File Mark, repositioning and reading are allowed again.
 */
static int  mode_access;	/* access mode: READ or WRITE */

static int qic02_get_resources(void);
static void qic02_release_resources(void);

/* This is a pointer to the actual kernel buffer where the interrupt routines
 * read from/write to. It is needed because the DMA channels 1 and 3 cannot
 * always access the user buffers. [The kernel buffer must reside in the
 * lower 16MBytes of system memory because of the DMA controller.] The user
 * must ensure that a large enough buffer is passed to the kernel, in order
 * to reduce tape repositioning wear and tear.
 */
static unsigned long buffaddr = 0;	/* physical address of buffer */

/* This translates minor numbers to the corresponding recording format: */
static const char *format_names[] = {
	"not set",	/* for dumb drives unable to handle format selection */
	"11",		/* extinct */
	"24",
	"120",
	"150",
	"300",		/* untested. */
	"600"		/* untested. */
};


/* `exception_list' is needed for exception status reporting.
 * Exceptions 1..14 are defined by QIC-02 rev F.
 * The drive status is matched sequentially to each entry,
 * ignoring irrelevant bits, until a match is found. If no
 * match is found, exception number 0 is used. (That should of
 * course never happen...) The original table was based on the
 * "Exception Status Summary" in QIC-02 rev F, but some changes
 * were required to make it work with real-world drives.
 *
 * Exception 2 (CNI) is changed to also cover status 0x00e0 (mask USL),
 * Exception 4 (EOM) is changed to also cover status 0x8288 (mask EOR),
 * Exception 11 (FIL) is changed to also cover status 0x0089 (mask EOM).
 * Exception 15 (EOR) is added for seek-to-end-of-data (catch EOR),
 * Exception 16 (BOM) is added for beginning-of-media (catch BOM).
 *
 * Had to swap EXC_NDRV and EXC_NCART to ensure that extended EXC_NCART
 * (because of the incorrect Wangtek status code) doesn't catch the
 * EXC_NDRV first.
 */
static struct exception_list_type {
	unsigned short mask, code;
	const char *msg;
	/* EXC_nr attribute should match with tpqic02.h */
} exception_list[] = {
	{0, 0,
		"Unknown exception status code",		/* extra: 0 */},
	{~(0), TP_ST0|TP_CNI|TP_USL|TP_WRP,
		"Drive not online"				/* 1 */},
		/* Drive presence goes before cartridge presence. */
	{~(TP_WRP|TP_USL), TP_ST0|TP_CNI,
		/* My Wangtek 5150EQ sometimes reports a status code
		 * of 0x00e0, which is not a valid exception code, but
		 * I think it should be recognized as "NO CARTRIDGE".
		 */
		"Cartridge not in place"			/* 2 */},
	{(unsigned short) ~(TP_ST1|TP_BOM), (TP_ST0|TP_WRP),
		"Write protected cartridge"			/* 3 */},
	{(unsigned short) ~(TP_ST1|TP_EOR), (TP_ST0|TP_EOM),
		"End of media"					/* 4 */},
	{~TP_WRP, TP_ST0|TP_UDA| TP_ST1|TP_BOM,
		"Read or Write abort. Rewind tape."		/* 5 */},
	{~TP_WRP, TP_ST0|TP_UDA,
		"Read error. Bad block transferred."		/* 6 */},
	{~TP_WRP, TP_ST0|TP_UDA|TP_BNL,
		"Read error. Filler block transferred."		/* 7 */},
	{~TP_WRP, TP_ST0|TP_UDA|TP_BNL |TP_ST1|TP_NDT,
		"Read error. No data detected."			/* 8 */},
	{~TP_WRP, TP_ST0|TP_EOM|TP_UDA|TP_BNL |TP_ST1|TP_NDT,
		"Read error. No data detected. EOM."		/* 9 */},
	{~(TP_WRP|TP_MBD|TP_PAR|TP_EOR), TP_ST0|TP_UDA|TP_BNL |TP_ST1|TP_NDT|TP_BOM,
		"Read error. No data detected. BOM."		/* 10 */},
	{~(TP_WRP|TP_EOM), TP_ST0|TP_FIL,
		/* Status 0x0089 (EOM & FM) is viewed as an FM,
		 * because it can only happen during a read.
		 * EOM is checked separately for an FM condition.
		 */
		"File mark detected"				/* 11 */},
	{~(TP_ST0|TP_CNI|TP_USL|TP_WRP|TP_BOM), TP_ST1|TP_ILL,
		"Illegal command"				/* 12 */},
	{~(TP_ST0|TP_CNI|TP_USL|TP_WRP|TP_BOM), TP_ST1|TP_POR,
		"Reset occurred"					/* 13 */},
	{~TP_WRP, TP_ST0|TP_FIL|TP_MBD,		/* NOTE: ST1 not set! */
		"Marginal block detected"			/* 14 */},
	{~(TP_ST0|TP_WRP|TP_EOM|TP_UDA|TP_BNL|TP_FIL |TP_NDT), TP_ST1|TP_EOR,
		/********** Is the extra TP_NDT really needed Eddy? **********/
		"End of recorded media"				/* extra: 15 */},
		/* 15 is returned when SEEKEOD completes successfully */
	{~(TP_WRP|TP_ST0), TP_ST1|TP_BOM,
		"Beginning of media"				/* extra: 16 */}
};
#define NR_OF_EXC	(sizeof(exception_list)/sizeof(struct exception_list_type))

/* Compare expected struct size and actual struct size. This
 * is useful to catch programs compiled with old #includes.
 */
#define CHECK_IOC_SIZE(structure) \
	if (_IOC_SIZE(iocmd) != sizeof(struct structure)) { \
		tpqputs(TPQD_ALWAYS, "sizeof(struct " #structure \
			") does not match!"); \
		return -EFAULT; \
	} \

static void tpqputs(unsigned long flags, const char *s)
{
	if ((flags & TPQD_ALWAYS) || (flags & QIC02_TAPE_DEBUG))
		printk(TPQIC02_NAME ": %s\n", s);
} /* tpqputs */


/* Perform byte order swapping for a 16-bit word.
 *
 * [FIXME] This should probably be in include/asm/
 * ([FIXME] i486 can do this faster)
 */
static inline void byte_swap_w(volatile unsigned short * w)
{
	int t = *w;

	*w = (t>>8) | ((t & 0xff)<<8);
}



/* Init control register bits on interface card.
 * For Archive, interrupts must be enabled explicitly.
 * Wangtek interface card requires ONLINE to be set, Archive SC402/SC499R
 * cards keep it active all the time.
 */
static void ifc_init(void)
{
    if (QIC02_TAPE_IFC == WANGTEK) /* || (QIC02_TAPE_IFC == EVEREX) */
    {
	ctlbits = WT_CTL_ONLINE;	/* online */
	outb_p(ctlbits, QIC02_CTL_PORT);
    }
    else if (QIC02_TAPE_IFC == ARCHIVE)
    {
	ctlbits = 0;			/* no interrupts yet */
	outb_p(ctlbits, QIC02_CTL_PORT);
	outb_p(0, AR_RESET_DMA_PORT);	/* dummy write to reset DMA */
    }
    else /* MOUNTAIN */
    {
	ctlbits = MTN_CTL_ONLINE;       /* online, and logic enabled */
	outb_p(ctlbits, QIC02_CTL_PORT);
    }
} /* ifc_init */


static void report_qic_exception(unsigned n)
{
    if (n >= NR_OF_EXC)
    {
	tpqputs(TPQD_ALWAYS, "Oops -- report_qic_exception");
	n = 0;
    }
    if (TPQDBG(SENSE_TEXT) || n==0)
    {
	printk(TPQIC02_NAME ": sense: %s\n", exception_list[n].msg);
    }
} /* report_qic_exception */


/* Try to map the drive-exception bits `s' to a predefined "exception number",
 * by comparing the significant exception bits for each entry in the
 * exception table (`exception_list[]').
 * It is assumed that s!=0.
 */
static int decode_qic_exception_nr(unsigned s)
{
    int i;

    for (i=1; i<NR_OF_EXC; i++)
    {
	if ((s & exception_list[i].mask)==exception_list[i].code)
	{
	    return i;
	}
    }
    printk(TPQIC02_NAME ": decode_qic_exception_nr: exception(%x) not recognized\n", s);
    return 0;
} /* decode_qic_exception_nr */



/* Perform appropriate action for certain exceptions.
 * should return a value to indicate stop/continue (in case of bad blocks)
 */
static void handle_qic_exception(int exnr, int exbits)
{
    if (exnr==EXC_NCART)
    {
	/* Cartridge was changed. Redo sense().
	 * EXC_NCART should be handled in open().
	 * It is not permitted to remove the tape while
	 * the tape driver has open files. 
	 */
	need_rewind = YES;
	status_eof_detected = NO;
	status_eom_detected = NO;
    }
    else if (exnr==EXC_XFILLER)
    {
	tpqputs(TPQD_ALWAYS, "[Bad block -- filler data transferred.]");
    }
    else if (exnr==EXC_XBAD)
    {
	tpqputs(TPQD_ALWAYS, "[CRC failed!]");
    }
    else if (exnr==EXC_MARGINAL)
    {
	/* A marginal block behaves much like a FM.
	 * User may continue reading, if desired.
	 */
	tpqputs(TPQD_ALWAYS, "[Marginal block]");
	doing_read = NO;
    }
    else if (exnr==EXC_FM)
    {
	doing_read = NO;
    }
} /* handle_qic_exception */


static inline int is_exception(void)
{
    return (inb(QIC02_STAT_PORT) & QIC02_STAT_EXCEPTION) == 0;
} /* is_exception */


/* Reset the tape drive and controller.
 * When reset fails, it marks  the drive as dead and all
 * requests (except reset) are to be ignored (ENXIO).
 */
static int tape_reset(int verbose)
{
    ifc_init();				/* reset interface card */

    /* assert reset */
    if (QIC02_TAPE_IFC == MOUNTAIN)
    {
	outb_p(ctlbits & ~MTN_QIC02_CTL_RESET_NOT, QIC02_CTL_PORT);
    }
    else /* WANGTEK, ARCHIVE */
    {
	outb_p(ctlbits | QIC02_CTL_RESET, QIC02_CTL_PORT);
    }
    
    /* Next, we need to wait >=25 usec. */
    udelay(30);

    /* after reset, we will be at BOT (modulo an automatic rewind) */
    status_eof_detected = NO;
    status_eom_detected = NO;
    status_cmd_pending = 0;
    need_rewind = YES;
    doing_read = doing_write = NO;
    ioctl_status.mt_fileno = ioctl_status.mt_blkno = 0;
    
    /* de-assert reset */
    if (QIC02_TAPE_IFC == MOUNTAIN)
    {
	outb_p(ctlbits | MTN_QIC02_CTL_RESET_NOT, QIC02_CTL_PORT);
    }
    else
    {
	outb_p(ctlbits & ~QIC02_CTL_RESET, QIC02_CTL_PORT);
    }
    
    /* KLUDGE FOR G++ BUG */
    { int stat = inb_p(QIC02_STAT_PORT);
	status_dead = ((stat & QIC02_STAT_RESETMASK) != QIC02_STAT_RESETVAL); }
    /* if successful, inb(STAT) returned RESETVAL */
    if (status_dead == YES)
    {
	printk(TPQIC02_NAME ": reset failed!\n");
    }
    else if (verbose)
    {
	printk(TPQIC02_NAME ": reset successful\n");
    }
    
    return (status_dead == YES)? TE_DEAD : TE_OK;
} /* tape_reset */



/* Notify tape drive of a new command. It only waits for the
 * command to be accepted, not for the actual command to complete.
 *
 * Before calling this routine, QIC02_CMD_PORT must have been loaded
 * with the command to be executed.
 * After this routine, the exception bit must be checked.
 * This routine is also used by rdstatus(), so in that case, any exception
 * must be ignored (`ignore_ex' flag).
 */
static int notify_cmd(char cmd, short ignore_ex)
{
	int i;

	outb_p(cmd, QIC02_CMD_PORT);    /* output the command */

	/* wait 1 usec before asserting /REQUEST */
	udelay(1);

	if ((!ignore_ex) && is_exception()) {
		tpqputs(TPQD_ALWAYS, "*** exception detected in notify_cmd");
		/** force a reset here **/
		if (tape_reset(1)==TE_DEAD)
			return TE_DEAD;
		if (is_exception()) {
			tpqputs(TPQD_ALWAYS, "exception persists after reset.");
			tpqputs(TPQD_ALWAYS, " ^ exception ignored.");
		}
	}

	outb_p(ctlbits | QIC02_CTL_REQUEST, QIC02_CTL_PORT);  /* set request bit */
	i = TAPE_NOTIFY_TIMEOUT;
	/* The specs say this takes about 500 usec, but there is no upper limit!
	 * If the drive were busy retensioning or something like that,
	 * it could be *much* longer!
	 */
	while ((inb_p(QIC02_STAT_PORT) & QIC02_STAT_READY) && (--i>0))
		/*skip*/;			  /* wait for ready */
	if (i==0) {
		tpqputs(TPQD_ALWAYS, "timed out waiting for ready in notify_cmd");
		status_dead = YES;
		return TE_TIM;
	}

	outb_p(ctlbits & ~QIC02_CTL_REQUEST, QIC02_CTL_PORT); /* reset request bit */
	i = TAPE_NOTIFY_TIMEOUT;
	/* according to the specs this one should never time-out */
	while (((inb_p(QIC02_STAT_PORT) & QIC02_STAT_READY) == 0) && (--i>0))
		/*skip*/;			  /* wait for not ready */
	if (i==0) {
		tpqputs(TPQD_ALWAYS, "timed out waiting for !ready in notify_cmd");
		status_dead = YES;
		return TE_TIM;
	}
	/* command accepted */
	return TE_OK;
} /* notify_cmd */



/* Wait for a command to complete, with timeout */
static int wait_for_ready(time_t timeout)
{
	int stat;
	time_t spin_t;

	/* Wait for ready or exception, without driving the loadavg up too much.
	 * In most cases, the tape drive already has READY asserted,
	 * so optimize for that case.
	 *
	 * First, busy wait a few usec:
	 */
	spin_t = 50;
	while (((stat = inb_p(QIC02_STAT_PORT) & QIC02_STAT_MASK) == QIC02_STAT_MASK) && (--spin_t>0))
		/*SKIP*/;
	if ((stat & QIC02_STAT_READY) == 0)
		return TE_OK;			/* covers 99.99% of all calls */

	/* Then use schedule() a few times */
	spin_t = 3;	/* max 0.03 sec busy waiting */
	if (spin_t > timeout)
		spin_t = timeout;
	timeout -= spin_t;
	spin_t += jiffies;

	while (((stat = inb_p(QIC02_STAT_PORT) & QIC02_STAT_MASK) == QIC02_STAT_MASK) && time_before(jiffies, spin_t))
		schedule();		/* don't waste all the CPU time */
	if ((stat & QIC02_STAT_READY) == 0)
		return TE_OK;

	/* If we reach this point, we probably need to wait much longer, or
	 * an exception occurred. Either case is not very time-critical.
	 * Check the status port only a few times every second.
	 * A interval of less than 0.10 sec will not be noticed by the user,
	 * more than 0.40 sec may give noticeable delays.
	 */
	spin_t += timeout;
	TPQDEB({printk("wait_for_ready: additional timeout: %d\n", spin_t);})

		/* not ready and no exception && timeout not expired yet */
	while (((stat = inb_p(QIC02_STAT_PORT) & QIC02_STAT_MASK) == QIC02_STAT_MASK) && time_before(jiffies, spin_t)) {
		/* be `nice` to other processes on long operations... */
		current->state = TASK_INTERRUPTIBLE;
		/* nap 0.30 sec between checks, */
		/* but could be woken up earlier by signals... */
		schedule_timeout(3*HZ/10);
	}

	/* don't use jiffies for this test because it may have changed by now */
	if ((stat & QIC02_STAT_MASK) == QIC02_STAT_MASK) {
		tpqputs(TPQD_ALWAYS, "wait_for_ready() timed out");
		return TE_TIM;
	}

	if ((stat & QIC02_STAT_EXCEPTION) == 0) {
		tpqputs(TPQD_ALWAYS, "exception detected after waiting_for_ready");
		return TE_EX;
	} else {
		return TE_OK;
	}
} /* wait_for_ready */



/* Send some data to the drive */
static int send_qic02_data(char sb[], unsigned size, int ignore_ex)
{
	int i, stat;

	for (i=0; i<size; i++) {

		stat = wait_for_ready(TIM_S);
		if (stat != TE_OK)
			return stat;

		stat = notify_cmd(sb[i], ignore_ex);
		if (stat != TE_OK)
			return stat;
	}
	return TE_OK;
	
} /* send_qic02_data */


/* Send a QIC-02 command (`cmd') to the tape drive, with
 * a time-out (`timeout').
 * This one is also used by tp_sense(), so we must have
 * a flag to disable exception checking (`ignore_ex'). 
 *
 * On entry, the controller is supposed to be READY.
 */
static int send_qic02_cmd(int cmd, time_t timeout, int ignore_ex)
{
	int stat;

	stat = inb_p(QIC02_STAT_PORT);
	if ((stat & QIC02_STAT_EXCEPTION) == 0) {	/* if exception */
		tpqputs(TPQD_ALWAYS, "send_qic02_cmd: Exception!");
		return TE_EX;
	}
	if (stat & QIC02_STAT_READY) {			/* if not ready */
		tpqputs(TPQD_ALWAYS, "send_qic02_cmd: not Ready!");
		return TE_ERR;
	}

	/* assert(ready & !exception) */

	/* Remember current command for later re-use with dma transfers.
	 * (For reading/writing multiple blocks.)
	 */
	status_cmd_pending = cmd;

	stat = notify_cmd(cmd, ignore_ex); /* tell drive new command was loaded, */
					   /* inherit exception check. */
	if (TP_HAVE_SEEK && (cmd == AR_QCMDV_SEEK_BLK)) {
		/* This one needs to send 3 more bytes, MSB first */
		stat = send_qic02_data(seek_addr_buf, sizeof(seek_addr_buf), ignore_ex);
	}

	if (stat != TE_OK) {
		tpqputs(TPQD_ALWAYS, "send_qic02_cmd failed");
	}
	return stat;
} /* send_qic02_cmd */



/* Get drive status. Assume drive is ready or has exception set.
 * (or will be in <1000 usec.)
 * Extra parameters added because of 'Read Extended Status 3' command.
 */
static int rdstatus(char *stp, unsigned size, char qcmd)
{
	int	s, n;
	char	*q = stp;

	/* Try to busy-wait a few (700) usec, after that de-schedule.
	 *
	 * The problem is, if we don't de-schedule, performance will
	 * drop to zero when the drive is not responding and if we
	 * de-schedule immediately, we waste a lot of time because a
	 * task switch is much longer than we usually have to wait here.
	 */
	n = 1000;	/* 500 is not enough on a 486/33 */
	while ((n>0) && ((inb_p(QIC02_STAT_PORT) & QIC02_STAT_MASK) == QIC02_STAT_MASK))
		n--;  /* wait for ready or exception or timeout */
	if (n==0) {
		/* n (above) should be chosen such that on your machine
		 * you rarely ever see the message below, and it should
		 * be small enough to give reasonable response time.]
		 */
		tpqputs(TPQD_ALWAYS, "waiting looong in rdstatus() -- drive dead?");
		while ((inb_p(QIC02_STAT_PORT) & QIC02_STAT_MASK) == QIC02_STAT_MASK)
			schedule();
		tpqputs(TPQD_ALWAYS, "finished waiting in rdstatus()");
	}

	(void) notify_cmd(qcmd, 1);			/* send read status command */
	/* ignore return code -- should always be ok, STAT may contain 
	 * exception flag from previous exception which we are trying to clear.
	 */

	if (TP_DIAGS(current_tape_dev))
		printk(TPQIC02_NAME ": reading status bytes: ");

	for (q=stp; q<stp+size; q++)
	{
		do s = inb_p(QIC02_STAT_PORT);
		while ((s & QIC02_STAT_MASK) == QIC02_STAT_MASK);	/* wait for ready or exception */

		if ((s & QIC02_STAT_EXCEPTION) == 0) {		/* if exception */
			tpqputs(TPQD_ALWAYS, "rdstatus: exception error");
			ioctl_status.mt_erreg = 0;		/* dunno... */
			return TE_NS;				/* error, shouldn't happen... */
		}

		*q = inb_p(QIC02_DATA_PORT);			/* read status byte */

		if (TP_DIAGS(current_tape_dev))
			printk("[%1d]=0x%x  ", q-stp, (unsigned) (*q) & 0xff);

		outb_p(ctlbits | QIC02_CTL_REQUEST, QIC02_CTL_PORT);	/* set request */

		while ((inb_p(QIC02_STAT_PORT) & QIC02_STAT_READY) == 0);	/* wait for not ready */

		udelay(22);	/* delay >20 usec */

		outb_p(ctlbits & ~QIC02_CTL_REQUEST, QIC02_CTL_PORT);	/* un-set request */

	}

	/* Specs say we should wait for READY here.
	 * My drive doesn't seem to need it here yet, but others do?
	 */
	while (inb_p(QIC02_STAT_PORT) & QIC02_STAT_READY)
		/*skip*/;			  /* wait for ready */

	if (TP_DIAGS(current_tape_dev))
		printk("\n");

	return TE_OK;
} /* rdstatus */



/* Get standard status (6 bytes).
 * The `.dec' and `.urc' fields are in MSB-first byte-order,
 * so they have to be swapped first.
 */
static int get_status(volatile struct tpstatus *stp)
{
	int stat = rdstatus((char *) stp, TPSTATSIZE, QCMD_RD_STAT);
#if defined(i386) || defined(i486)
	byte_swap_w(&(stp->dec));
	byte_swap_w(&(stp->urc));
#else
	/* should probably swap status bytes #definition */
#endif
	return stat;
} /* get_status */


#if 0
/* This fails for my Wangtek drive */
/* get "Extended Status Register 3" (64 bytes)
 *
 * If the meaning of the returned bytes were known, the MT_TYPE
 * identifier could be used to decode them, since they are
 * "vendor unique". :-(
 */
static int get_ext_status3(void)
{
	char vus[64];	/* vendor unique status */
	int stat, i;

	tpqputs(TPQD_ALWAYS, "Attempting to read Extended Status 3...");
	stat = rdstatus(vus, sizeof(vus), QCMD_RD_STAT_X3);
	if (stat != TE_OK)
		return stat;

	tpqputs(TPQD_ALWAYS, "Returned status bytes:");
	for (i=0; i<sizeof(vus); i++) {
		if ( i % 8 == 0 )
			printk("\n" TPQIC02_NAME ": %2d:");
		printk(" %2x", vus[i] & 0xff);
	}
	printk("\n");

	return TE_OK;
} /* get_ext_status3 */
#endif


/* Read drive status and set generic status too.
 * NOTE: Once we do a tp_sense(), read/write transfers are killed.
 */
static int tp_sense(int ignore)
{
	unsigned err = 0, exnr = 0, gs = 0;
	static void finish_rw(int cmd);

	if (TPQDBG(SENSE_TEXT))
		printk(TPQIC02_NAME ": tp_sense(ignore=0x%x) enter\n", ignore);

	/* sense() is not allowed during a read or write cycle */
	if (doing_write == YES)
		tpqputs(TPQD_ALWAYS, "Warning: File Mark inserted because of sense() request");
	/* The extra test is to avoid calling finish_rw during booting */
	if ((doing_read!=NO) || (doing_write!=NO))
		finish_rw(QCMD_RD_STAT);

	if (get_status(&tperror) != TE_OK) {
		tpqputs(TPQD_ALWAYS, "tp_sense: could not read tape drive status");
		return TE_ERR;
	}

	err = tperror.exs;	/* get exception status bits */
	if (err & (TP_ST0|TP_ST1))
		printk(TPQIC02_NAME ": tp_sense: status: %x, error count: %d, underruns: %d\n",
			tperror.exs, tperror.dec, tperror.urc);
	else if ((tperror.dec!=0) || (tperror.urc!=0) || TPQDBG(SENSE_CNTS))
		printk(TPQIC02_NAME ": tp_sense: no hard errors, soft error count: %d, underruns: %d\n",
			tperror.dec, tperror.urc);

	/* Set generic status. HP-UX defines these, but some extra would 
	 * be useful. Problem is to remain compatible. [Do we want to be
	 * compatible??]
	 */
	if (err & TP_ST0) {
		if (err & TP_CNI)		/* no cartridge */
			gs |= GMT_DR_OPEN(-1);
		if (status_dead == NO)
			gs |= GMT_ONLINE(-1);	/* always online */
		if (err & TP_USL)		/* not online */
			gs &= ~GMT_ONLINE(-1);
		if (err & TP_WRP)
			gs |= GMT_WR_PROT(-1);
		if (err & TP_EOM) {		/* end of media */
			gs |= GMT_EOT(-1);	/* not sure this is correct for writes */
			status_eom_detected = YES;
			/* I don't know whether drive always reports EOF at or before EOM. */
			status_eof_detected = YES;
		}
		/** if (err & TP_UDA) "Unrecoverable data error" **/
		/** if (err & TP_BNL) "Bad block not located" **/
		if (err & TP_FIL) {
			gs |= GMT_EOF(-1);
			status_eof_detected = YES;
		}
	}
	if (err & TP_ST1) {
		/** if (err & TP_ILL) "Illegal command" **/
		/** if (err & TP_NDT) "No data detected" **/
		/** if (err & TP_MBD) "Marginal block detected" **/
		if (err & TP_BOM)
			gs |= GMT_BOT(-1);	/* beginning of tape */
	}
	ioctl_status.mt_gstat = gs;
	ioctl_status.mt_dsreg = tperror.exs;	/* "drive status" */
	ioctl_status.mt_erreg = tperror.dec;	/* "sense key error" */

	if (err & (TP_ST0|TP_ST1)) {
		/* My Wangtek occasionally reports `status' 1212 which should be ignored. */
		exnr = decode_qic_exception_nr(err);
		handle_qic_exception(exnr, err);		/* update driver state wrt drive status */
		report_qic_exception(exnr);
	}
	err &= ~ignore;		/* mask unwanted errors -- not the correct way, use exception nrs?? */
	if (((err & TP_ST0) && (err & REPORT_ERR0)) ||
	    ((err & TP_ST1) && (err & REPORT_ERR1)))
		return TE_ERR;
	return TE_OK;
} /* tp_sense */



/* Wait for a wind or rewind operation to finish or
 * to time-out. (May take very long).
 */
static int wait_for_rewind(time_t timeout)
{
	int stat;

	stat = inb(QIC02_STAT_PORT) & QIC02_STAT_MASK;
	if (TPQDBG(REWIND))
		printk(TPQIC02_NAME ": Waiting for (re-)wind to finish: stat=0x%x\n", stat);

	stat = wait_for_ready(timeout);

	if (stat != TE_OK) {
			tpqputs(TPQD_ALWAYS, "(re-) winding failed\n");
	}
	return stat;
} /* wait_for_rewind */



/* Perform a full QIC02 command, and wait for completion,
 * check status when done. Complain about exceptions.
 *
 * This function should return an OS error code when
 * something goes wrong, 0 otherwise.
 */
static int ll_do_qic_cmd(int cmd, time_t timeout)
{
	int stat;

	if (status_dead == YES) {
		tpqputs(TPQD_ALWAYS, "Drive is dead. Do a `mt reset`.");
		return -ENXIO;			/* User should do an MTRESET. */
	}

	stat = wait_for_ready(timeout);		/* wait for ready or exception */
	if (stat == TE_EX) {
		if (tp_sense(TP_WRP|TP_BOM|TP_EOM|TP_FIL)!=TE_OK)
			return -EIO;
		/* else nothing to worry about, I hope */
		stat = TE_OK;
	}
	if (stat != TE_OK) {
		printk(TPQIC02_NAME ": ll_do_qic_cmd(%x, %ld) failed\n", cmd, (long) timeout);
		return -EIO;
	}


#if OBSOLETE
	/* wait for ready since it may not be active immediately after reading status */
	while ((inb_p(QIC02_STAT_PORT) & QIC02_STAT_READY) != 0);
#endif

	stat = send_qic02_cmd(cmd, timeout, 0);	/* (checks for exceptions) */

	if (cmd==QCMD_RD_FM) {
		status_eof_detected = NO;
		ioctl_status.mt_fileno++;
		/* Should update block count as well, but can't.
		 * Can do a `read address' for some drives, when MTNOP is done.
		 */
	} else if (cmd==QCMD_WRT_FM) {
		status_eof_detected = NO;
		ioctl_status.mt_fileno++;
	} else if ((cmd==QCMD_REWIND) || (cmd==QCMD_ERASE) || (cmd==QCMD_RETEN)) {
		status_eof_detected = NO;
		status_eom_detected = NO;
		status_eot_detected = NO;
		need_rewind = NO;
		ioctl_status.mt_fileno = ioctl_status.mt_blkno = 0;
		extra_blocks_left = BLOCKS_BEYOND_EW;
		return_write_eof = NO;
		return_read_eof = NO;
		reported_read_eof = NO;
		reported_write_eof = NO;
	}
	/* sense() will set eof/eom as required */
	if (stat==TE_EX) {
		if (tp_sense(TP_WRP|TP_BOM|TP_EOM|TP_FIL)!=TE_OK) {
			printk(TPQIC02_NAME ": Exception persist in ll_do_qic_cmd[1](%x, %ld)", cmd, (long) timeout);
			status_dead = YES;
			return -ENXIO;
			/* if rdstatus fails too, we're in trouble */
		}
	}
	else if (stat!=TE_OK) {
		printk(TPQIC02_NAME ": ll_do_qic_cmd: send_qic02_cmd failed, stat = 0x%x\n", stat);
		return -EIO;	/*** -EIO is probably not always appropriate */
	}


	if (timeout == TIM_R)
		stat = wait_for_rewind(timeout);
	else
		stat = wait_for_ready(timeout);

	if (stat==TE_EX) {
		if (tp_sense((cmd==QCMD_SEEK_EOD ?		/*****************************/
		      TP_EOR|TP_NDT|TP_UDA|TP_BNL|TP_WRP|TP_BOM|TP_EOM|TP_FIL :
		      TP_WRP|TP_BOM|TP_EOM|TP_FIL))!=TE_OK) {
			printk(TPQIC02_NAME ": Exception persist in ll_do_qic_cmd[2](%x, %ld)\n", cmd, (long) timeout);
			if (cmd!=QCMD_RD_FM)
				status_dead = YES;
			return -ENXIO;
			/* if rdstatus fails too, we're in trouble */
		}
	}
	else if (stat!=TE_OK) {
		printk(TPQIC02_NAME ": ll_do_qic_cmd %x: wait failed, stat == 0x%x\n", cmd, stat);
		return -EIO;
	}
	return 0;
} /* ll_do_qic_cmd */


/* 
 * Problem: What to do when the user cancels a read/write operation
 * in-progress?
 *
 * "Deactivating ONLINE during a READ also causes the"
 * "tape to be rewound to BOT." Ditto for WRITEs, except
 * a FM is written first. "The host may alternatively terminate
 * the READ/WRITE command by issuing a RFM/WFM command."
 *
 * For READs:
 * Neither option will leave the tape positioned where it was.
 * Another (better?) solution is to terminate the READ by two
 * subsequent sense() operations, the first to stop the current
 * READ cycle, the second to clear the `Illegal command' exception,
 * because the QIC-02 specs didn't anticipate this. This is
 * delayed until actually needed, so a tar listing can be aborted
 * by the user and continued later.
 * If anybody has a better solution, let me know! [Also, let me
 * know if your drive (mine is a Wangtek5150EQ) does not accept
 * this sequence for canceling the read-cycle.]
 *
 * For WRITEs it's simple: Just do a WRITE_FM, leaving the tape
 * positioned after the FM.
 */

static void terminate_read(int cmd)
{
	if (doing_read == YES) {
		doing_read = NO;
		if (cmd != QCMD_RD_FM) {
			/* if the command is a RFM, there is no need to do this
			 * because a RFM will legally terminate the read-cycle.
			 */
			tpqputs(TPQD_ALWAYS, "terminating pending read-cycle");

			/* I'm not too sure about this part  -- hhb */
			if (QIC02_TAPE_IFC == MOUNTAIN) {
				/* Mountain reference says can terminate by de-asserting online */
				ctlbits &= ~MTN_QIC02_CTL_ONLINE;
			}
 
			if (tp_sense(TP_FIL|TP_EOM|TP_WRP) != TE_OK) {
				tpqputs(TPQD_ALWAYS, "finish_rw[read1]: ignore the 2 lines above");
				if (is_exception()) {
					if (tp_sense(TP_ILL|TP_FIL|TP_EOM|TP_WRP) != TE_OK)
						tpqputs(TPQD_ALWAYS, "finish_rw[read2]: read cycle error");
				}
			}
		}
	}
} /* terminate_read */


static void terminate_write(int cmd)
{
	int stat;

	if (doing_write == YES) {
		doing_write = NO;
		/* Finish writing by appending a FileMark at the end. */
		if (cmd != QCMD_WRT_FM) {
			/* finish off write cycle */
			stat = ll_do_qic_cmd(QCMD_WRT_FM, TIM_M);
			if (stat != TE_OK)
				tpqputs(TPQD_ALWAYS, "Couldn't finish write cycle properly");
			(void) tp_sense(0);
		}
		/* If there is an EOF token waiting to be returned to
		 * the (writing) application, discard it now.
		 * We could be at EOT, so don't reset return_write_eof.
		 */
		reported_write_eof=YES;
	}
} /* terminate_write */


/* terminate read or write cycle because of command `cmd' */
static void finish_rw(int cmd)
{
	if (wait_for_ready(TIM_S) != TE_OK) {
		tpqputs(TPQD_ALWAYS, "error: drive not ready in finish_rw() !");
		return;
	}
	terminate_read(cmd);
	terminate_write(cmd);
} /* finish_rw */


/* Perform a QIC command through ll_do_qic_cmd().
 * If necessary, rewind the tape first.
 * Return an OS error code if something goes wrong, 0 if all is well.
 */
static int do_qic_cmd(int cmd, time_t timeout)
{
	int stat;


	finish_rw(cmd);

	if (need_rewind) {
		tpqputs(TPQD_REWIND, "Rewinding tape...");
		stat = ll_do_qic_cmd(QCMD_REWIND, TIM_R);
		if (stat != 0) {
			printk(TPQIC02_NAME ": rewind failed in do_qic_cmd(). stat=0x%2x", stat);
			return stat;
		}
		need_rewind = NO;
		if (cmd==QCMD_REWIND)	/* don't wind beyond BOT ;-) */
			return 0;
	}

	return ll_do_qic_cmd(cmd, timeout);
} /* do_qic_cmd */


/* Not all ioctls are supported for all drives. Some rely on
 * optional QIC-02 commands. Check tpqic02.h for configuration.
 * Some of these commands may require ONLINE to be active.
 */
static int do_ioctl_cmd(int cmd)
{
	int stat;

	/* It is not permitted to read or wind the tape after bytes have
	 * been written. It is not permitted to write the tape while in
	 * read mode.
	 * We try to be kind and allow reading again after writing a FM...
	 */

	switch (cmd) {
		case MTRESET:
			/* reset verbose */
			return (tape_reset(1)==TE_OK)? 0 : -EIO;

		case MTFSF:
			tpqputs(TPQD_IOCTLS, "MTFSF forward searching filemark");
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			return do_qic_cmd(QCMD_RD_FM, TIM_F);

		case MTBSF:
			if (TP_HAVE_BSF) {
				tpqputs(TPQD_IOCTLS, "MTBSF backward searching filemark -- optional command");
				if ((mode_access==WRITE) && status_bytes_wr)
					return -EACCES;
				stat = do_qic_cmd(QCMD_RD_FM_BCK, TIM_F);
			} else {
				stat = -ENXIO;
			}
			status_eom_detected = status_eof_detected = NO;
			return stat;

		case MTFSR:
			if (TP_HAVE_FSR) { /* This is an optional QIC-02 command */
				tpqputs(TPQD_IOCTLS, "MTFSR forward space record");
				if ((mode_access==WRITE) && status_bytes_wr)
					return -EACCES;
				stat = do_qic_cmd(QCMD_SPACE_FWD, TIM_F);
			} else {
				/**** fake it by doing a read data block command? ******/
				tpqputs(TPQD_IOCTLS, "MTFSR not supported");
				stat = -ENXIO;
			}
			return stat;

		case MTBSR:
			if (TP_HAVE_BSR) { /* This is an optional QIC-02 command */
				/* we need this for appending files with GNU tar!! */
				tpqputs(TPQD_IOCTLS, "MTFSR backward space record");
				if ((mode_access==WRITE) && status_bytes_wr)
					return -EACCES;
				stat = do_qic_cmd(QCMD_SPACE_BCK, TIM_F);
			} else {
				tpqputs(TPQD_IOCTLS, "MTBSR not supported");
				stat = -ENXIO;
			}
			status_eom_detected = status_eof_detected = NO;
			return stat;

		case MTWEOF:
			tpqputs(TPQD_IOCTLS, "MTWEOF write eof mark");
			/* Plain GNU mt(1) 2.2 uses read-only mode for writing FM. :-( */
			if (mode_access==READ)
				return -EACCES;

			/* allow tape movement after writing FM */
			status_bytes_rd = status_bytes_wr;	/* Kludge-O-Matic */
			status_bytes_wr = NO;
			return do_qic_cmd(QCMD_WRT_FM, TIM_M);
			/* not sure what to do with status_bytes when WFM should fail */

		case MTREW:
			tpqputs(TPQD_IOCTLS, "MTREW rewinding tape");
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			status_eom_detected = status_eof_detected = NO;
			return do_qic_cmd(QCMD_REWIND, TIM_R);

		case MTOFFL:
			tpqputs(TPQD_IOCTLS, "MTOFFL rewinding & going offline");
			/* Doing a drive select will clear (unlock) the current drive.
			 * But that requires support for multiple drives and locking.
			 */
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			status_eom_detected = status_eof_detected = NO;
			/**** do rewind depending on minor bits??? ***/
			stat = do_qic_cmd(QCMD_REWIND, TIM_R);
			return stat;

		case MTNOP:
			tpqputs(TPQD_IOCTLS, "MTNOP setting status only");
			/********** should do `read position' for drives that support it **********/
			return (tp_sense(-1)==TE_OK)? 0 : -EIO;	/**** check return codes ****/

		case MTRETEN:
			tpqputs(TPQD_IOCTLS, "MTRETEN retension tape");
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			status_eom_detected = status_eof_detected = NO;
			return do_qic_cmd(QCMD_RETEN, TIM_R);

		case MTBSFM:
			/* Think think is like MTBSF, except that
			 * we shouldn't skip the FM. Tricky.
			 * Maybe use RD_FM_BCK, then do a SPACE_FWD?
			 */
			tpqputs(TPQD_IOCTLS, "MTBSFM not supported");
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			return -ENXIO;

		case MTFSFM:
			/* I think this is like MTFSF, except that
			 * we shouldn't skip the FM. Tricky.
			 * Maybe use QCMD_RD_DATA until we get a TP_FIL exception?
			 * But then the FM will have been skipped...
			 * Maybe use RD_FM, then RD_FM_BCK, but not all
			 * drives will support that!
			 */
			tpqputs(TPQD_IOCTLS, "MTFSFM not supported");
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			return -ENXIO;

		case MTEOM:
			/* This should leave the tape ready for appending
			 * another file to the end, such that it would append
			 * after the last FM on tape.
			 */
			tpqputs(TPQD_IOCTLS, "MTEOM search for End Of recorded Media");
			if ((mode_access==WRITE) && status_bytes_wr)
				return -EACCES;
			if (TP_HAVE_EOD) {
				/* Use faster seeking when possible.
				 * This requires the absence of data beyond the EOM.
				 * It seems that my drive does not always perform the
				 * SEEK_EOD correctly, unless it is preceded by a
				 * rewind command.
				 */
# if 0
				status_eom_detected = status_eof_detected = NO;
# endif
				stat = do_qic_cmd(QCMD_REWIND, TIM_R);
				if (stat)
					return stat;
				stat = do_qic_cmd(QCMD_SEEK_EOD, TIM_F);
				/* After a successful seek, TP_EOR should be returned */
			} else {
				/* else just seek until the drive returns exception "No Data" */
				stat = 0;
				while ((stat==0) && (!status_eom_detected)) {
					stat = do_qic_cmd(QCMD_RD_FM, TIM_F); /***** should use MTFSFM here???? ******/
				}
				if (tperror.exs & TP_NDT)
					return 0;
			}
			return stat;

		case MTERASE:
			tpqputs(TPQD_IOCTLS, "MTERASE -- ERASE TAPE !");
			if  ((tperror.exs & TP_ST0) && (tperror.exs & TP_WRP)) {
				tpqputs(TPQD_ALWAYS, "Cartridge is write-protected.");
				return -EACCES;
			} else {
				time_t t = jiffies;

				/* Plain GNU mt(1) 2.2 erases a tape in O_RDONLY. :-( */
				if (mode_access==READ) 
					return -EACCES;

				/* give user a few seconds to pull out tape */
				while (jiffies - t < 4*HZ)
					schedule();
			}

			/* don't bother writing filemark first */
			status_eom_detected = status_eof_detected = NO;
			return do_qic_cmd(QCMD_ERASE, TIM_R);

		case MTRAS1:
			if (TP_HAVE_RAS1) {
				tpqputs(TPQD_IOCTLS, "MTRAS1: non-destructive self test");
				stat = do_qic_cmd(QCMD_SELF_TST1, TIM_R);
				if (stat != 0) {
					tpqputs(TPQD_ALWAYS, "RAS1 failed");
					return stat;
				}
				return (tp_sense(0)==TE_OK)? 0 : -EIO; /* get_ext_status3(); */
			}
			tpqputs(TPQD_IOCTLS, "RAS1 not supported");
			return -ENXIO;

		case MTRAS2:
			if (TP_HAVE_RAS2) {
				tpqputs(TPQD_IOCTLS, "MTRAS2: destructive self test");
				stat = do_qic_cmd(QCMD_SELF_TST2, TIM_R);
				if (stat != 0) {
					tpqputs(TPQD_ALWAYS, "RAS2 failed");
					return stat;
				}
				return (tp_sense(0)==TE_OK)? 0 : -EIO; /* get_ext_status3(); */
			}
			tpqputs(TPQD_IOCTLS, "RAS2 not supported");
			return -ENXIO;

		case MTSEEK:
			if (TP_HAVE_SEEK && (QIC02_TAPE_IFC==ARCHIVE)) {
				tpqputs(TPQD_IOCTLS, "MTSEEK seeking block");
				if ((mode_access==WRITE) && status_bytes_wr)
					return -EACCES;
				/* NOTE: address (24 bits) is in seek_addr_buf[] */
				return do_qic_cmd(AR_QCMDV_SEEK_BLK, TIM_F);
			}
			else
				return -ENOTTY;

		default:
			return -ENOTTY;
	}
} /* do_ioctl_cmd */


/* dma_transfer(): This routine is called for every 512 bytes to be read
 * from/written to the tape controller. Speed is important here!
 * (There must be enough time left for the hd controller!)
 * When other devices use DMA they must ensure they use un-interruptible
 * double byte accesses to the DMA controller. Floppy.c is ok.
 * Must have interrupts disabled when this function is invoked,
 * otherwise, the double-byte transfers to the DMA controller will not
 * be atomic. That could lead to nasty problems when they are interrupted
 * by other DMA interrupt-routines.
 *
 * This routine merely does the least possible to keep
 * the transfers going:
 *	- set the DMA count register for the next 512 bytes
 *	- adjust the DMA address and page registers
 *	- adjust the timeout
 *	- tell the tape controller to start transferring
 * We assume the dma address and mode are, and remain, valid.
 */ 
static inline void dma_transfer(void)
{
	unsigned long flags;

	if (QIC02_TAPE_IFC == WANGTEK) /* or EVEREX */
		outb_p(WT_CTL_ONLINE, QIC02_CTL_PORT);	/* back to normal */
	else if (QIC02_TAPE_IFC == ARCHIVE)
		outb_p(0, AR_RESET_DMA_PORT);
	else /* QIC02_TAPE_IFC == MOUNTAIN */
		outb_p(ctlbits, QIC02_CTL_PORT);


	flags=claim_dma_lock();
	clear_dma_ff(QIC02_TAPE_DMA);
	set_dma_mode(QIC02_TAPE_DMA, dma_mode);
	set_dma_addr(QIC02_TAPE_DMA, buffaddr+dma_bytes_done);	/* full address */
	set_dma_count(QIC02_TAPE_DMA, TAPE_BLKSIZE);

	/* start tape DMA controller */
	if (QIC02_TAPE_IFC == WANGTEK) /* or EVEREX */
		outb_p(WT_CTL_DMA | WT_CTL_ONLINE, QIC02_CTL_PORT); /* trigger DMA transfer */

	else if (QIC02_TAPE_IFC == ARCHIVE) {
		outb_p(AR_CTL_IEN | AR_CTL_DNIEN, QIC02_CTL_PORT);  /* enable interrupts again */
		outb_p(0, AR_START_DMA_PORT);			  /* start DMA transfer */
		/* In dma_end() AR_RESET_DMA_PORT is written too. */

	} else /* QIC02_TAPE_IFC == MOUNTAIN */ {
		inb(MTN_R_DESELECT_DMA_PORT);
		outb_p(ctlbits | (MTN_CTL_EXC_IEN | MTN_CTL_DNIEN), QIC02_CTL_PORT);
		outb_p(0, MTN_W_SELECT_DMA_PORT);	 /* start DMA transfer */
		if (dma_mode == DMA_MODE_WRITE)
			outb_p(0, MTN_W_DMA_WRITE_PORT); /* start DMA transfer */
	}

	/* start computer DMA controller */
	enable_dma(QIC02_TAPE_DMA);

	release_dma_lock(flags);

	/* block transfer should start now, jumping to the 
	 * interrupt routine when done or an exception was detected.
	 */
} /* dma_transfer */


/* start_dma() sets a DMA transfer up between the tape controller and
 * the kernel qic02_tape_buf buffer.
 * Normally bytes_todo==dma_bytes_done at the end of a DMA transfer. If not,
 * a filemark was read, or an attempt to write beyond the End Of Tape 
 * was made. [Or some other bad thing happened.]
 * Must do a sense() before returning error.
 */
static int start_dma(short mode, unsigned long bytes_todo)
/* assume 'bytes_todo'>0 */
{
	int stat;
	unsigned long flags;
	
	tpqputs(TPQD_DEBUG, "start_dma() enter");
	TPQDEB({printk(TPQIC02_NAME ": doing_read==%d, doing_write==%d\n", doing_read, doing_write);})

	dma_bytes_done = 0;
	dma_bytes_todo = bytes_todo;
	status_error = NO;
	/* dma_mode!=0 indicates that the dma controller is in use */
	dma_mode = (mode == WRITE)? DMA_MODE_WRITE : DMA_MODE_READ;	

	/* Only give READ/WRITE DATA command to tape drive if we haven't
	 * done that already. Otherwise the drive will rewind to the beginning
	 * of the current file on tape. Any QIC command given other than
	 * R/W FM will break the read/write transfer cycle.
	 * do_qic_cmd() will terminate doing_{read,write}
	 */
	if ((doing_read == NO) && (doing_write == NO)) {
		/* First, we have to clear the status -- maybe remove TP_FIL???
		 */

#if 0
		/* Next dummy get status is to make sure CNI is valid,
                   since we're only just starting a read/write it doesn't
                   matter some exceptions are cleared by reading the status;
                   we're only interested in CNI and WRP. -Eddy */
		get_status(&tperror);
#else
		/* TP_CNI should now be handled in open(). -Hennus */
#endif

		stat = tp_sense(((mode == WRITE)? 0 : TP_WRP) | TP_BOM | TP_FIL);
		if (stat != TE_OK)
			return stat;

#if OBSOLETE
		/************* not needed iff rd_status() would wait for ready!!!!!! **********/
		if (wait_for_ready(TIM_S) != TE_OK) {	/*** not sure this is needed ***/
			tpqputs(TPQD_ALWAYS, "wait_for_ready failed in start_dma");
			return -EIO;
		}
#endif

		if (QIC02_TAPE_IFC == MOUNTAIN) {
			/* Set control bits to select ONLINE during command */
			ctlbits |= MTN_QIC02_CTL_ONLINE;
		}

		/* Tell the controller the data direction */

		/* r/w, timeout medium, check exceptions, sets status_cmd_pending. */
		stat = send_qic02_cmd((mode == WRITE)? QCMD_WRT_DATA : QCMD_RD_DATA, TIM_M, 0);
		if (stat!=TE_OK) {
			printk(TPQIC02_NAME ": start_dma: init %s failed\n",
				(mode == WRITE)? "write" : "read");
			(void) tp_sense(0);
			return stat;
		}

		/* Do this last, because sense() will clear the doing_{read,write}
		 * flags, causing trouble next time around.
		 */
		if (wait_for_ready(TIM_M) != TE_OK)
			return -EIO;
		switch (mode) {
			case READ:
				doing_read = YES;
				break;
			case WRITE:
				doing_write = YES;
				break;
			default:
				printk(TPQIC02_NAME ": requested unknown mode %d\n", mode);
				panic(TPQIC02_NAME ": invalid mode in start_dma()");
		}

	} else if (is_exception()) {
		/* This is for Archive drives, to handle reads with 0 bytes
		 * left for the last read request.
		 *
		 * ******** this also affects EOF/EOT handling! ************
		 */
		tpqputs(TPQD_ALWAYS, "detected exception in start_dma() while transfer in progress");
		status_error = YES;
		return TE_END;
	}


	status_expect_int = YES;

	/* This assumes tape is already positioned, but these
	 * semi-'intelligent' drives are unpredictable...
	 */
	TIMERON(TIM_M*2);

	/* initiate first data block read from/write to the tape controller */

	save_flags(flags);
	cli();
	dma_transfer();
	restore_flags(flags);

	TPQPUTS("start_dma() end");
	return TE_OK;
} /* start_dma */


/* This cleans up after the dma transfer has completed
 * (or failed). If an exception occurred, a sense()
 * must be done. If the exception was caused by a FM,
 * sense() will set `status_eof_detected' and
 * `status_eom_detected', as required.
 */
static void end_dma(unsigned long * bytes_done)
{
	int stat = TE_OK;
	unsigned long flags;

	TIMEROFF;

	TPQPUTS("end_dma() enter");

	flags=claim_dma_lock();
	
	disable_dma(QIC02_TAPE_DMA);
	clear_dma_ff(QIC02_TAPE_DMA);
	
	release_dma_lock(flags);

	if (QIC02_TAPE_IFC == WANGTEK) /* or EVEREX */
		outb_p(WT_CTL_ONLINE, QIC02_CTL_PORT);	/* back to normal */
	else if (QIC02_TAPE_IFC == ARCHIVE)
		outb_p(0, AR_RESET_DMA_PORT);
	else /* QIC02_TAPE_IFC == MOUNTAIN */ {
		/* Clear control bits, de-select ONLINE during tp_sense */
		ctlbits &= ~MTN_QIC02_CTL_ONLINE;
	}

	stat = wait_for_ready(TIM_M);
	if (status_error || (stat!=TE_OK)) {
		tpqputs(TPQD_DMAX, "DMA transfer exception");
		stat = tp_sense((dma_mode==READ)? TP_WRP : 0);
		/* no return here -- got to clean up first! */
	} else /* if (QIC02_TAPE_IFC == MOUNTAIN) */ {
		outb_p(ctlbits, QIC02_CTL_PORT);
	}

	if (QIC02_TAPE_IFC == MOUNTAIN)
		inb(MTN_R_DESELECT_DMA_PORT);

 	/* take the tape controller offline */

	/* finish off DMA stuff */


	dma_mode = 0;
	/* Note: The drive is left on-line, ready for the next
	 * data transfer.
	 * If the next command to the drive does not continue
	 * the pending cycle, it must do 2 sense()s first.
	 */

	*bytes_done = dma_bytes_done;
	status_expect_int = NO;
	ioctl_status.mt_blkno += (dma_bytes_done / TAPE_BLKSIZE);

	TPQPUTS("end_dma() exit");
	/*** could return stat here ***/
} /* end_dma */

/*********** Below are the (public) OS-interface procedures ***********/


/* qic02_tape_times_out() is called when a DMA transfer doesn't complete
 * quickly enough. Usually this means there is something seriously wrong
 * with the hardware/software, but it could just be that the controller
 * has decided to do a long rewind, just when I didn't expect it.
 * Just try again.
 */
static void qic02_tape_times_out(void)
{
	printk("time-out in %s driver\n", TPQIC02_NAME);
	if ((status_cmd_pending>0) || dma_mode) {
		/* takes tooo long, shut it down */
		status_dead = YES;
		status_cmd_pending = 0;
		status_timer_on = NO;
		status_expect_int = NO;
		status_error = YES;
		if (dma_mode) {
			dma_mode = 0;	/* signal end to read/write routine */
			wake_up(&qic02_tape_transfer);
		}
	}
} /* qic02_tape_times_out */

/*
 * Interrupt handling:
 *
 * 1) Interrupt is generated iff at the end of 
 *    a 512-DMA-block transfer.
 * 2) EXCEPTION is not raised unless something 
 *    is wrong or EOT/FM is detected.
 * 3) FM EXCEPTION is set *after* the last byte has
 *    been transferred by DMA. By the time the interrupt
 *    is handled, the EXCEPTION may already be set.
 *
 * So,
 * 1) On EXCEPTION, assume data has been transferred, so
 *    continue as usual, but set a flag to indicate the
 *    exception was detected.
 *    Do a sense status when the flag is found set.
 * 2) Do not attempt to continue a transfer after an exception.
 *    [??? What about marginal blocks???????]
 */


/* qic02_tape_interrupt() is called when the tape controller completes 
 * a DMA transfer.
 * We are not allowed to sleep here! 
 *
 * Check if the transfer was successful, check if we need to transfer
 * more. If the buffer contains enough data/is empty enough, signal the
 * read/write() thread to copy to/from user space.
 * When we are finished, set flags to indicate end, disable timer.
 * NOTE: This *must* be fast! 
 */
static void qic02_tape_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	int stat, r, i;
	unsigned long flags;

	TIMEROFF;

	if (status_expect_int) {
#ifdef WANT_EXTRA_FULL_DEBUGGING
		if (TP_DIAGS(current_tape_dev))
			printk("@");
#endif
		stat = inb(QIC02_STAT_PORT);	/* Knock, knock */
		if (QIC02_TAPE_IFC == ARCHIVE) {	/* "Who's there?" */
			if (((stat & (AR_STAT_DMADONE)) == 0) &&
        	              ((stat & (QIC02_STAT_EXCEPTION)) != 0)) {
				TIMERCONT;
				return;			/* "Linux with IRQ sharing" */
			}
		}

		if ((stat & QIC02_STAT_EXCEPTION) == 0) {	/* exception occurred */
			/* Possible causes for an exception during a transfer:
			 * 	- during a write-cycle: end of tape (EW) hole detected.
			 *	- during a read-cycle: filemark or EOD detected.
			 *	- something went wrong
			 * So don't continue with the next block.
			 */
			tpqputs(TPQD_ALWAYS, "isr: exception on tape controller");
			printk("      status %02x\n", stat);
			status_error = TE_EX;

			dma_bytes_done += TAPE_BLKSIZE;

			dma_mode = 0;	/* wake up rw() */
			status_expect_int = NO;
			wake_up(&qic02_tape_transfer);
			return;
		}
		/* return if tape controller not ready, or
		 * if dma channel hasn't finished last byte yet.
		 */
		r = 0;

	    /* Skip next ready check for Archive controller because
	     * it may be busy reading ahead. Weird. --hhb
	     */
		if (QIC02_TAPE_IFC == WANGTEK)	/* I think this is a drive-dependency, not IFC -- hhb */
			if (stat & QIC02_STAT_READY) {		/* not ready */
				tpqputs(TPQD_ALWAYS, "isr: ? Tape controller not ready");
				r = 1;
			}

		flags=claim_dma_lock();
		
		if ( (i = get_dma_residue(QIC02_TAPE_DMA)) != 0 ) {
			printk(TPQIC02_NAME ": dma_residue == %x !!!\n", i);
			r = 1;	/* big trouble, but can't do much about it... */
		}
		
		release_dma_lock(flags);

		if (r) 
			return;

		/* finish DMA cycle */

		/* no errors detected, continue */
		dma_bytes_done += TAPE_BLKSIZE;
		if (dma_bytes_done >= dma_bytes_todo) {
			/* finished! Wakeup rw() */
			dma_mode = 0;
			status_expect_int = NO;
			TPQPUTS("isr: dma_bytes_done");
			wake_up(&qic02_tape_transfer);
		} else {
			/* start next transfer, account for track-switching time */
			timer_table[QIC02_TAPE_TIMER].expires = jiffies + 6*HZ;
			dma_transfer();
		}
	} else {
		printk(TPQIC02_NAME ": Unexpected interrupt, stat == %x\n",
		       inb(QIC02_STAT_PORT));
	}
} /* qic02_tape_interrupt */


static long long qic02_tape_lseek(struct file * file, long long offset, int origin)
{
	return -EINVAL;	/* not supported */
} /* qic02_tape_lseek */


/* read/write routines:
 * This code copies between a kernel buffer and a user buffer. The 
 * actual data transfer is done using DMA and interrupts. Time-outs
 * are also used.
 *
 * When a filemark is read, we return '0 bytes read' and continue with the
 * next file after that.
 * When EOM is read, we return '0 bytes read' twice.
 * When the EOT marker is detected on writes, '0 bytes read' should be
 * returned twice. If user program does a MTNOP after that, 2 additional
 * blocks may be written.	------- FIXME: Implement this correctly  *************************************************
 *
 * Only read/writes in multiples of 512 bytes are accepted.
 * When no bytes are available, we sleep() until they are. The controller will
 * generate an interrupt, and we (should) get a wake_up() call.
 *
 * Simple buffering is used. User program should ensure that a large enough
 * buffer is used. Usually the drive does some buffering as well (something
 * like 4k or so).
 *
 * Scott S. Bertilson suggested to continue filling the user buffer, rather
 * than waste time on a context switch, when the kernel buffer fills up.
 */

/*
 * Problem: tar(1) doesn't always read the entire file. Sometimes the entire file
 * has been read, but the EOF token is never returned to tar(1), simply because
 * tar(1) knows it has already read all of the data it needs. So we must use
 * open/release to reset the `reported_read_eof' flag. If we don't, the next read
 * request would return the EOF flag for the previous file.
 */

static ssize_t qic02_tape_read(struct file * filp, char * buf, size_t count, loff_t *ppos)
{
    int err;
    kdev_t dev = filp->f_dentry->d_inode->i_rdev;
    unsigned short flags = filp->f_flags;
    unsigned long bytes_todo, bytes_done, total_bytes_done = 0;
    int stat;

    if (status_zombie==YES)
    {
	tpqputs(TPQD_ALWAYS, "configs not set");		
	return -ENXIO;
    }

    if (TP_DIAGS(current_tape_dev))
      /* can't print a ``long long'' (for filp->f_pos), so chop it */
      printk(TPQIC02_NAME ": request READ, minor=%x, buf=%p, count=%lx"
	                  ", pos=%lx, flags=%x\n",
	     MINOR(dev), buf, (long) count,
	     (unsigned long) filp->f_pos, flags);
    
    if (count % TAPE_BLKSIZE)	/* Only allow mod 512 bytes at a time. */
    {
	tpqputs(TPQD_BLKSZ, "Wrong block size");
	return -EINVAL;
    }

    /* Just assume everything is ok. Controller will scream if not. */

    if (status_bytes_wr)	/* Once written, no more reads, 'till after WFM. */
    {
	return -EACCES;
    }
    
    /* This is rather ugly because it has to implement a finite state
     * machine in order to handle the EOF situations properly.
     */
    while ((signed)count>=0)
    {
	bytes_done = 0;
	/* see how much fits in the kernel buffer */
	bytes_todo = TPQBUF_SIZE;
	if (bytes_todo>count)
	{
	    bytes_todo = count;
	}
	
	/* Must ensure that user program sees exactly one EOF token (==0) */
	if (return_read_eof==YES)
	{
	    if (TPQDBG(DEBUG))
	    {
		printk("read: return_read_eof==%d, reported_read_eof==%d, total_bytes_done==%lu\n", return_read_eof, reported_read_eof, total_bytes_done);
	    }
	    
	    if (reported_read_eof==NO)
	    {
		/* have not yet returned EOF to user program */
		if (total_bytes_done>0)
		{
		    return total_bytes_done; /* next time return EOF */
		}
		else
		{
		    reported_read_eof = YES; /* move on next time */
		    return 0;		 /* return EOF */
		}				
	    }
	    else
	    {
		/* Application program has already received EOF
		 * (above), now continue with next file on tape,
		 * if possible.
		 * When the FM is reached, EXCEPTION is set,
		 * causing a sense(). Subsequent read/writes will
		 * continue after the FM.
		 */
		/*********** ?????????? this should check for (EOD|NDT), not EOM, 'cause we can read past EW: ************/
		if (status_eom_detected)
		{
		    /* If EOM, nothing left to read, so keep returning EOFs.
		     *** should probably set some flag to avoid clearing
		     *** status_eom_detected through ioctls or something
		     */
		    return 0;
		}
		else
		{
		    /* just eof, there may be more files ahead... */
		    return_read_eof = NO;
		    reported_read_eof = NO;
		    status_eof_detected = NO; /* reset this too */
		    /*fall through*/
		}
	    }
	}
	
	/*****************************/
	if (bytes_todo==0)
	{
	    return total_bytes_done;
	}
	
	if (bytes_todo>0)
	{
	    /* start reading data */
	    if (is_exception())	/****************************************/
	    {
		tpqputs(TPQD_DMAX, "is_exception() before start_dma()!");
	    }
	    
/******************************************************************
 ***** if start_dma() fails because the head is positioned 0 bytes
 ***** before the FM, (causing EXCEPTION to be set) return_read_eof should
 ***** be set to YES, and we should return total_bytes_done, rather than -ENXIO.
 ***** The app should recognize this as an EOF condition.
 ***************************************************************************/
	    stat = start_dma(READ, bytes_todo);
	    if (stat == TE_OK)
	    {
		/* Wait for transfer to complete, interrupt should wake us */
		while (dma_mode != 0)
		{
		    sleep_on(&qic02_tape_transfer);
		}
		if (status_error)
		{
		    return_read_eof = YES;
		}
		
	    }
	    else if (stat != TE_END)
	    {
		/* should do sense() on error here */
#if 0
		return -ENXIO;
#else
		printk("Trouble: stat==%02x\n", stat);
		return_read_eof = YES;
		/*************** check EOF/EOT handling!!!!!! **/
#endif
	    }
	    end_dma(&bytes_done);
	    if (bytes_done>bytes_todo)
	    {
		tpqputs(TPQD_ALWAYS, "read: Oops, read more bytes than requested");
		return -EIO;
	    }
	    /* copy buffer to user-space in one go */
	    if (bytes_done>0)
	    {
		err = copy_to_user( (void *) buf, (void *) bus_to_virt(buffaddr), bytes_done);
		if (err)
		{
		    return -EFAULT;
		}
	    }
#if 1
	    /* Checks Ton's patch below */
	    if ((return_read_eof == NO) && (status_eof_detected == YES))
	    {
		printk(TPQIC02_NAME ": read(): return_read_eof=%d, status_eof_detected=YES. return_read_eof:=YES\n", return_read_eof);
	    }
#endif
	    if ((bytes_todo != bytes_done) || (status_eof_detected == YES))
	    {
		/* EOF or EOM detected. return EOF next time. */
		return_read_eof = YES;
	    }
	    
	} /* else: ignore read request for 0 bytes */

	if (bytes_done>0)
	{
	    status_bytes_rd = YES;
	    buf += bytes_done;
	    *ppos += bytes_done;
	    total_bytes_done += bytes_done;
	    count -= bytes_done;
	}
    }
    tpqputs(TPQD_ALWAYS, "read request for <0 bytes");
    return -EINVAL;
} /* qic02_tape_read */



/* The drive detects near-EOT by means of the holes in the tape.
 * When the holes are detected, there is some space left. The drive
 * reports this as a TP_EOM exception. After clearing the exception,
 * the drive should accept two extra blocks.
 *
 * It seems there are some archiver programs that would like to use the
 * extra space for writing a continuation marker. The driver should return
 * end-of-file to the user program on writes, when the holes are detected.
 * If the user-program wants to use the extra space, it should use the
 * MTNOP ioctl() to get the generic status register and may then continue
 * writing (max 1kB).	----------- doesn't work yet...............
 *
 * EOF behaviour on writes:
 * If there is enough room, write all of the data.
 * If there is insufficient room, write as much as will fit and
 * return the amount written. If the requested amount differs from the
 * written amount, the application program should recognize that as the
 * end of file. Subsequent writes will return -ENOSPC.
 * Unless the minor bits specify a rewind-on-close, the tape will not
 * be rewound when it is full. The user-program should do that, if desired.
 * If the driver were to do that automatically, a user-program could be 
 * confused about the EOT/BOT condition after re-opening the tape device.
 *
 * Multiple volume support: Tar closes the tape device before prompting for
 * the next tape. The user may then insert a new tape and tar will open the
 * tape device again. The driver will detect an exception status in (No Cartridge)
 * and force a rewind. After that tar may continue writing.
 */
static ssize_t qic02_tape_write( struct file * filp,  const char * buf, 
		size_t count, loff_t *ppos)
{
    int err;
    kdev_t dev = filp->f_dentry->d_inode->i_rdev;
    unsigned short flags = filp->f_flags;
    unsigned long bytes_todo, bytes_done, total_bytes_done = 0;
    
    if (status_zombie==YES)
    {
	tpqputs(TPQD_ALWAYS, "configs not set");		
	return -ENXIO;
    }

    if (TP_DIAGS(current_tape_dev))
    {
	/* can't print a ``long long'' (for filp->f_pos), so chop it */
	printk(TPQIC02_NAME ": request WRITE, minor=%x, buf=%p"
	                    ", count=%lx, pos=%lx, flags=%x\n",
	       MINOR(dev), buf,
	       (long) count, (unsigned long) filp->f_pos, flags);
    }
    
    if (count % TAPE_BLKSIZE) 	/* only allow mod 512 bytes at a time */
    {
	tpqputs(TPQD_BLKSZ, "Wrong block size");
	return -EINVAL;
    }

    if (mode_access==READ)
    {
	tpqputs(TPQD_ALWAYS, "Not in write mode");
	return -EACCES;
    }

    /* open() does a sense() and we can assume the tape isn't changed
     * between open() and release(), so the tperror.exs bits will still
     * be valid.
     */
    if ((tperror.exs & TP_ST0) && (tperror.exs & TP_WRP))
    {
	tpqputs(TPQD_ALWAYS, "Cartridge is write-protected.");
	return -EACCES;	/* don't even try when write protected */
    }
      
    if (doing_read == YES)
    {
	terminate_read(0);
    }
    
    while ((signed)count>=0)
    {
	/* see how much fits in the kernel buffer */
	bytes_done = 0;
	bytes_todo = TPQBUF_SIZE;
	if (bytes_todo>count)
	{
	    bytes_todo = count;
	}
	
	if (return_write_eof == YES)
	{
	    /* return_write_eof should be reset on reverse tape movements. */
	    
	    if (reported_write_eof==NO)
	    {
		if (bytes_todo>0)
		{
		    tpqputs(TPQD_ALWAYS, "partial write");
		    /* partial write signals EOF to user program */
		}
		reported_write_eof = YES;
		return total_bytes_done;
	    }
	    else
	    {
		return -ENOSPC;		 /* return error */
	    }	
	}
	
	/* Quit when done. */
	if (bytes_todo==0)
	{
	    return total_bytes_done;
	}
	
	/* copy from user to DMA buffer and initiate transfer. */
	if (bytes_todo>0)
	{
	    err = copy_from_user( (void *) bus_to_virt(buffaddr), (const void *) buf, bytes_todo);
	    if (err)
	    {
		return -EFAULT;
	    }

/****************** similar problem with read() at FM could happen here at EOT.
 ******************/

/***** if at EOT, 0 bytes can be written. start_dma() will
 ***** fail and write() will return ENXIO error
 *****/
	    if (start_dma(WRITE, bytes_todo) != TE_OK)
	    {
		tpqputs(TPQD_ALWAYS, "write: start_dma() failed");
		/* should do sense() on error here */
		return -ENXIO;	/*********** FIXTHIS **************/
	    }

	    /* Wait for write to complete, interrupt should wake us. */
	    while ((status_error == 0) && (dma_mode != 0))
	    {
		sleep_on(&qic02_tape_transfer);
	    }

	    end_dma(&bytes_done);
	    if (bytes_done>bytes_todo)
	    {
		tpqputs(TPQD_ALWAYS, "write: Oops, wrote more bytes than requested");
		return -EIO;
	    }
	    /* If the dma-transfer was aborted because of an exception,
	     * status_error will have been set in the interrupt handler.
	     * Then end_dma() will do a sense().
	     * If the exception was EXC_EOM, the EW-hole was encountered
	     * and two more blocks could be written. For the time being we'll
	     * just consider this to be the EOT.
	     * Otherwise, something Bad happened, such as the maximum number
	     * of block-rewrites was exceeded. [e.g. A very bad spot on tape was
	     * encountered. Normally short dropouts are compensated for by
	     * rewriting the block in error, up to 16 times. I'm not sure
	     * QIC-24 drives can do this.]
	     */
	    if (status_error)
	    {
		if (status_eom_detected == YES)
		{
		    tpqputs(TPQD_ALWAYS, "write: EW detected");
		    return_write_eof = YES;
		}
		else
		{
		    /* probably EXC_RWA */
		    tpqputs(TPQD_ALWAYS, "write: dma: error in writing");
		    return -EIO;
		}
	    }
	    if (bytes_todo != bytes_done)
	    {
		/* EOF or EOM detected. return EOT next time. */
		return_write_eof = YES;
	    }
	}
	/* else: ignore write request for 0 bytes. */
	
	if (bytes_done>0)
	{
	    status_bytes_wr = YES;
	    buf += bytes_done;
	    *ppos += bytes_done;
	    total_bytes_done += bytes_done;
	    count -= bytes_done;
	}
    }
    
    tpqputs(TPQD_ALWAYS, "write request for <0 bytes");
    if (TPQDBG(DEBUG))
    {
	printk(TPQIC02_NAME ": status_bytes_wr %x, buf %p"
	                    ", total_bytes_done %lx, count %lx\n",
	       status_bytes_wr, buf, total_bytes_done, (long) count);
    }
    return -EINVAL;
} /* qic02_tape_write */



/* qic02_tape_open()
 * We allow the device to be opened, even if it is marked 'dead' because
 * we want to be able to reset the tape device without rebooting.
 * Only one open tape file at a time, except when minor=255.
 * Minor 255 is only allowed for resetting and always returns <0.
 * 
 * The density command is only allowed when TP_BOM is set. Thus, remember
 * the most recently used minor bits. When they are different from the
 * remembered values, rewind the tape and set the required density.
 * Don't rewind if the minor bits specify density 0.
 */

static int qic02_tape_open(struct inode * inode, struct file * filp)
{
    static int qic02_tape_open_no_use_count(struct inode *, struct file *);
    int open_error;

    open_error = qic02_tape_open_no_use_count(inode, filp);
    if (!open_error)
    {
	MOD_INC_USE_COUNT;
    }
    return open_error;
}

static int qic02_tape_open_no_use_count(struct inode * inode, struct file * filp)
{
    kdev_t dev = inode->i_rdev;
    unsigned short flags = filp->f_flags;
    unsigned short dens = 0;
    int s;


    if (TP_DIAGS(dev))
    {
	printk("qic02_tape_open: dev=%s, flags=%x     ",
	       kdevname(dev), flags);
    }

    if (MINOR(dev)==255)	/* special case for resetting */
    {
	if (suser())
	{
	    return (tape_reset(1)==TE_OK) ? -EAGAIN : -ENXIO;
	}
	else
	{
	    return -EPERM;
	}
    }
    
    if (status_dead==YES)
    {
	/* Allow `mt reset' ioctl() even when already open()ed. */
	return 0;
    }
    
	/* Only one at a time from here on... */
    if (filp->f_count>1) 	/* filp->f_count==1 for the first open() */
    {
	return -EBUSY;
    }

    if (status_zombie==YES)
    {
	/* no irq/dma/port stuff allocated yet, no reset done
	 * yet, so return until MTSETCONFIG has been done.
	 */
	return 0;
    }
    
    status_bytes_rd = NO;
    status_bytes_wr = NO;
    
    return_read_eof = NO;	/********????????????????*****/
    return_write_eof = (status_eot_detected)? YES : NO;

    /* Clear this in case user app close()d before reading EOF token */
    status_eof_detected = NO;

    reported_read_eof = NO;
    reported_write_eof = NO;


    switch (flags & O_ACCMODE)
    {
     case O_RDONLY:
	mode_access = READ;
	break;
     case O_WRONLY:	/* Fallthru... Strictly speaking this is not correct... */
     case O_RDWR:	/* Reads are allowed as long as nothing is written */
	mode_access = WRITE;
	break;
    }
    
    /* This is to avoid tape-changed problems (TP_CNI exception).
     *
     * Since removing the cartridge will not raise an exception,
     * we always do a tp_sense() to make sure we have the proper
     * CNI status, the 2150L may need an additional sense.... - Eddy
     */
    s = tp_sense(TP_WRP|TP_EOM|TP_BOM|TP_CNI|TP_EOR);
    
    if (s == TE_OK)
    {
	/* Try to clear cartridge-changed status for Archive-2150L */
	if ((tperror.exs & TP_ST0) && (tperror.exs & TP_CNI))
	{
	    s = tp_sense(TP_WRP|TP_EOM|TP_BOM|TP_CNI|TP_EOR);
	}
    }
    
    if (s != TE_OK)
    {
	tpqputs(TPQD_ALWAYS, "open: sense() failed");
	return -EIO;
    }

    /* exception bits should be up-to-date now, so check for
     * tape presence and exit if absent.
     * Even `mt stat' will fail without a tape.
     */
    if ((tperror.exs & TP_ST0) && (tperror.exs & TP_CNI))
    {
	tpqputs(TPQD_ALWAYS, "No tape present.");
	return -EIO;
    }

    /* At this point we can assume that a tape is present and
     * that it will remain present until release() is called.
     */

    /* not allowed to do QCMD_DENS_* unless tape is rewound */
    if ((TP_DENS(dev)!=0) && (TP_DENS(current_tape_dev) != TP_DENS(dev)))
    {
	/* force rewind if minor bits have changed,
	 * i.e. user wants to use tape in different format.
	 * [assuming single drive operation]
	 */
	if (TP_HAVE_DENS)
	{
	    tpqputs(TPQD_REWIND, "Density minor bits have changed. Forcing rewind.");
	    need_rewind = YES;
	}
    }
    else
    {
	/* density bits still the same, but TP_DIAGS bit 
	 * may have changed.
	 */
	current_tape_dev = dev;
    }
    
    if (need_rewind == YES)  /***************** CHECK THIS!!!!!!!! **********/
    {
	s = do_qic_cmd(QCMD_REWIND, TIM_R);
	if (s != 0)
	{
	    tpqputs(TPQD_ALWAYS, "open: rewind failed");
	    return -EIO;
	}
    }


/* Note: After a reset command, the controller will rewind the tape
 *	 just before performing any tape movement operation! ************ SO SET need_rewind flag!!!!!
 */ 
    if (status_dead==YES)
    {
	tpqputs(TPQD_ALWAYS, "open: tape dead, attempting reset");
	if (tape_reset(1)!=TE_OK)
	{
	    return -ENXIO;
	}
	else
	{
	    status_dead = NO;
	    if (tp_sense(~(TP_ST1|TP_ILL)) != TE_OK)
	    {
		tpqputs(TPQD_ALWAYS, "open: tp_sense() failed\n");
		status_dead = YES;	/* try reset next time */
		return -EIO;
	    }
	}
    }
    
    /* things should be ok, once we get here */
    

    /* set density: only allowed when TP_BOM status bit is set,
     * so we must have done a rewind by now. If not, just skip over.
     * Only give set density command when minor bits have changed.
     */
    if (TP_DENS(current_tape_dev) == TP_DENS(dev) )
    {
	return 0;
    }
    
    current_tape_dev = dev;
    need_rewind = NO;
    if (TP_HAVE_DENS)
    {
	dens = TP_DENS(dev);
    }
    
    if (dens < sizeof(format_names)/sizeof(char *))
    {
	printk(TPQIC02_NAME ": format: %s%s\n", (dens!=0)? "QIC-" : "", format_names[dens]);
    }
    else
    {
	tpqputs(TPQD_REWIND, "Wait for retensioning...");
    }
    
    switch (TP_DENS(dev))
    {
     case 0: /* Minor 0 is for drives without set-density support */
	s = 0;
	break;
     case 1:
	s = do_qic_cmd(QCMD_DENS_11, TIM_S);
	break;
     case 2:
	s = do_qic_cmd(QCMD_DENS_24, TIM_S);
	break;
     case 3:
	s = do_qic_cmd(QCMD_DENS_120, TIM_S);
	break;
     case 4:
	s = do_qic_cmd(QCMD_DENS_150, TIM_S);
	break;
     case 5:
	s = do_qic_cmd(QCMD_DENS_300, TIM_S);
	break;
     case 6:
	s = do_qic_cmd(QCMD_DENS_600, TIM_S);
	break;
     default:  /* otherwise do a retension before anything else */
	s = do_qic_cmd(QCMD_RETEN, TIM_R);
    }
    if (s != 0)
    {
	status_dead = YES;	/* force reset */
	current_tape_dev = 0; /* earlier 0xff80 */
	return -EIO;
    }
    
    return 0;
} /* qic02_tape_open */


static int qic02_tape_release(struct inode * inode, struct file * filp)
{
    kdev_t dev = inode->i_rdev;

    if (TP_DIAGS(dev))
    {
	printk("qic02_tape_release: dev=%s\n",  kdevname(dev));
    }
    
    if (status_zombie==NO)		/* don't rewind in zombie mode */
    {
	/* Terminate any pending write cycle. Terminating the read-cycle
	 * is delayed until it is required to do so for a new command.
	 */
	terminate_write(-1);
	
	if (status_dead==YES)
	{
	    tpqputs(TPQD_ALWAYS, "release: device dead!?");
	}
	
	/* Rewind only if minor number requires it AND 
	 * read/writes have been done. ************* IS THIS CORRECT??????????
	 */
	if ((TP_REWCLOSE(dev)) && (status_bytes_rd | status_bytes_wr))
	{
	    tpqputs(TPQD_REWIND, "release: Doing rewind...");
	    (void) do_qic_cmd(QCMD_REWIND, TIM_R);
	}
    }
#ifdef MODULE
    MOD_DEC_USE_COUNT;
#endif
    return 0;
} /* qic02_tape_release */


#ifdef CONFIG_QIC02_DYNCONF
/* Set masks etc. based on the interface card type. */
static int update_ifc_masks(int ifc)
{
    QIC02_TAPE_IFC = ifc;

    if ((QIC02_TAPE_IFC == WANGTEK) || (QIC02_TAPE_IFC == EVEREX))
    {
	QIC02_STAT_PORT = QIC02_TAPE_PORT;
	QIC02_CTL_PORT = QIC02_TAPE_PORT;
	QIC02_CMD_PORT = QIC02_TAPE_PORT+1;
	QIC02_DATA_PORT = QIC02_TAPE_PORT+1;
	QIC02_STAT_READY = WT_QIC02_STAT_READY;
	QIC02_STAT_EXCEPTION = WT_QIC02_STAT_EXCEPTION;
	QIC02_STAT_MASK = WT_QIC02_STAT_MASK;
	
	QIC02_STAT_RESETMASK = WT_QIC02_STAT_RESETMASK;
	QIC02_STAT_RESETVAL = WT_QIC02_STAT_RESETVAL;
	
	QIC02_CTL_RESET = WT_QIC02_CTL_RESET;
	QIC02_CTL_REQUEST = WT_QIC02_CTL_REQUEST;
 
	if (QIC02_TAPE_DMA == 3)
	{
	    WT_CTL_DMA = WT_CTL_DMA3;
	}
	else if (QIC02_TAPE_DMA == 1)
	{
	    WT_CTL_DMA = WT_CTL_DMA1;
	}
	else
	{
	    tpqputs(TPQD_ALWAYS, "Unsupported or incorrect DMA channel");
	    return -EIO;
	} 

	if (QIC02_TAPE_IFC == EVEREX)
	{
	    /* Everex is a special case for Wangtek (actually
	     * it's the other way 'round, but I saw Wangtek first)
	     */
	    if (QIC02_TAPE_DMA==3)
	    {
		WT_CTL_DMA = WT_CTL_DMA1;
	    }
	    
	    /* Fixup the kernel copy of the IFC type to that
	     * we don't have to distinguish between Wangtek and
	     * and Everex at runtime.
	     */
	    QIC02_TAPE_IFC = WANGTEK;
	}
    }
    else if (QIC02_TAPE_IFC == ARCHIVE)
    {
	QIC02_STAT_PORT = QIC02_TAPE_PORT+1;
	QIC02_CTL_PORT = QIC02_TAPE_PORT+1;
	QIC02_CMD_PORT = QIC02_TAPE_PORT;
	QIC02_DATA_PORT = QIC02_TAPE_PORT;
	QIC02_STAT_READY = AR_QIC02_STAT_READY;
	QIC02_STAT_EXCEPTION  = AR_QIC02_STAT_EXCEPTION;
	QIC02_STAT_MASK = AR_QIC02_STAT_MASK;
	
	QIC02_STAT_RESETMASK = AR_QIC02_STAT_RESETMASK;
	QIC02_STAT_RESETVAL = AR_QIC02_STAT_RESETVAL;
	
	QIC02_CTL_RESET = AR_QIC02_CTL_RESET;
	QIC02_CTL_REQUEST = AR_QIC02_CTL_REQUEST;
	
	if (QIC02_TAPE_DMA > 3)
	{
	    tpqputs(TPQD_ALWAYS, "Unsupported or incorrect DMA channel");
	    return -EIO;
	} 
    }
    else if (QIC02_TAPE_IFC == MOUNTAIN)
    {
	QIC02_STAT_PORT = QIC02_TAPE_PORT+1;
	QIC02_CTL_PORT = QIC02_TAPE_PORT+1;
	QIC02_CMD_PORT = QIC02_TAPE_PORT;
	QIC02_DATA_PORT = QIC02_TAPE_PORT;
	
	QIC02_STAT_READY = MTN_QIC02_STAT_READY;
	QIC02_STAT_EXCEPTION  = MTN_QIC02_STAT_EXCEPTION;
	QIC02_STAT_MASK = MTN_QIC02_STAT_MASK;
	
	QIC02_STAT_RESETMASK = MTN_QIC02_STAT_RESETMASK;
	QIC02_STAT_RESETVAL = MTN_QIC02_STAT_RESETVAL;
	
	QIC02_CTL_RESET = MTN_QIC02_CTL_RESET;
	QIC02_CTL_REQUEST = MTN_QIC02_CTL_REQUEST;
	
	if (QIC02_TAPE_DMA > 3)
	{
	    tpqputs(TPQD_ALWAYS, "Unsupported or incorrect DMA channel");
	    return -EIO;
	} 
    }
    else
    {
	tpqputs(TPQD_ALWAYS, "Invalid interface type");
	return -ENXIO;
    }
    return qic02_get_resources();
} /* update_ifc_masks */
#endif


/* ioctl allows user programs to rewind the tape and stuff like that */
static int qic02_tape_ioctl(struct inode * inode, struct file * filp, 
		     unsigned int iocmd, unsigned long ioarg)
{
    int error;
    int dev_maj = MAJOR(inode->i_rdev);
    int c;
    struct mtop operation;
    unsigned char blk_addr[6];
    struct mtpos ioctl_tell;
    

    if (TP_DIAGS(current_tape_dev))
    {
	printk(TPQIC02_NAME ": ioctl(%4x, %4x, %4lx)\n", dev_maj, iocmd, ioarg);
    }
    
    if (!inode || !ioarg)
    {
	return -EINVAL;
    }
    
    /* check iocmd first */

    if (dev_maj != QIC02_TAPE_MAJOR)
    {
	printk(TPQIC02_NAME ": Oops! Wrong device?\n");
	/* A panic() would be appropriate here */
	return -ENODEV;
    }

    c = _IOC_NR(iocmd);

#ifdef CONFIG_QIC02_DYNCONF
    if (c == _IOC_NR(MTIOCGETCONFIG))
    {
	CHECK_IOC_SIZE(mtconfiginfo);

	if (copy_to_user((char *) ioarg, (char *) &qic02_tape_dynconf, sizeof(qic02_tape_dynconf)))
	{
	    return -EFAULT;
	}
	return 0;

    }
    else if (c == _IOC_NR(MTIOCSETCONFIG))
    {
	/* One should always do a MTIOCGETCONFIG first, then update
	 * user-settings, then write back with MTIOCSETCONFIG.
	 * The qic02conf program should re-open() the device before actual
	 * use, to make sure everything is initialized.
	 */
	
	CHECK_IOC_SIZE(mtconfiginfo);
	
	if (!suser())
	{
	    return -EPERM;
	}
	
	if ((doing_read!=NO) || (doing_write!=NO))
	{
	    return -EBUSY;
	}
	
	if (status_zombie==NO)
	{
	    qic02_release_resources();	/* and go zombie */
	}
	
	/* copy struct from user space to kernel space */
	if (copy_from_user((char *) &qic02_tape_dynconf, (char *) ioarg, sizeof(qic02_tape_dynconf)))
	{
	    return -EFAULT;
	}
	return update_ifc_masks(qic02_tape_dynconf.ifc_type);
    }
    if (status_zombie==YES)
    {
	tpqputs(TPQD_ALWAYS, "Configs not set");
	return -ENXIO;
    }
#endif
    if (c == _IOC_NR(MTIOCTOP))
    {
	CHECK_IOC_SIZE(mtop);

	/* copy mtop struct from user space to kernel space */
	if (copy_from_user((char *) &operation, (char *) ioarg, sizeof(operation)))
	{
	    return -EFAULT;
	}

	/* ---note: mt_count is signed, negative seeks must be
	 * ---	    translated to seeks in opposite direction!
	 * (only needed for Sun-programs, I think.)
	 */
	/* ---note: MTFSF with count 0 should position the
	 * ---	    tape at the beginning of the current file.
	 */

	if (TP_DIAGS(current_tape_dev))
	{
	    printk("OP op=%4x, count=%4x\n", operation.mt_op, operation.mt_count);
	}
	
	if (operation.mt_count < 0)
	{
	    tpqputs(TPQD_ALWAYS, "Warning: negative mt_count ignored");
	}
	
	ioctl_status.mt_resid = operation.mt_count;
	if (operation.mt_op == MTSEEK)
	{
	    if (!TP_HAVE_SEEK)
	    {
		return -ENOTTY;
	    }
	    
	    seek_addr_buf[0] = (operation.mt_count>>16)&0xff;
	    seek_addr_buf[1] = (operation.mt_count>>8)&0xff;
	    seek_addr_buf[2] = (operation.mt_count)&0xff;
	    if (operation.mt_count>>24)
	    {
		return -EINVAL;
	    }
	    if ((error = do_ioctl_cmd(operation.mt_op)) != 0)
	    {
		return error;
	    }
	    
	    ioctl_status.mt_resid = 0;
	}
	else
	{
	    while (operation.mt_count > 0)
	    {
		operation.mt_count--;
		if ((error = do_ioctl_cmd(operation.mt_op)) != 0)
		{
		    return error;
		}
		
		ioctl_status.mt_resid = operation.mt_count;
	    }
	}
	return 0;
	
    }
    else if (c == _IOC_NR(MTIOCGET))
    {
	if (TP_DIAGS(current_tape_dev))
	{
	    printk("GET ");
	}
	
	CHECK_IOC_SIZE(mtget);

	/* It appears (gmt(1)) that it is normal behaviour to
	 * first set the status with MTNOP, and then to read
	 * it out with MTIOCGET
	 */

	/* copy results to user space */
	if (copy_to_user((char *) ioarg, (char *) &ioctl_status, sizeof(ioctl_status)))
	{
	    return -EFAULT;
	}	
	return 0;
    }
    else if (TP_HAVE_TELL && (c == _IOC_NR(MTIOCPOS)))
    {
	if (TP_DIAGS(current_tape_dev))
	{
	    printk("POS ");
	}
	
	CHECK_IOC_SIZE(mtpos);
	
	tpqputs(TPQD_IOCTLS, "MTTELL reading block address");
	if ((doing_read==YES) || (doing_write==YES))
	{
	    finish_rw(AR_QCMDV_TELL_BLK);
	}
	
	c = rdstatus((char *) blk_addr, sizeof(blk_addr), AR_QCMDV_TELL_BLK);
	if (c!=TE_OK)
	{
	    return -EIO;
	}
	
	ioctl_tell.mt_blkno = (blk_addr[3] << 16) | (blk_addr[4] << 8) | blk_addr[5];

	/* copy results to user space */
	if (copy_to_user((char *) ioarg, (char *) &ioctl_tell, sizeof(ioctl_tell)))
	{
	    return -EFAULT;
	}
	return 0;

    }
    else
    {
	return -ENOTTY;	/* Other cmds not supported. */
    }
} /* qic02_tape_ioctl */



/* These are (most) of the interface functions: */
static struct file_operations qic02_tape_fops = {
	qic02_tape_lseek,		/* not allowed */
	qic02_tape_read,		/* read */
	qic02_tape_write,		/* write */
	NULL,				/* readdir not allowed */
	NULL,				/* poll ??? */
	qic02_tape_ioctl,		/* ioctl */
	NULL,				/* mmap not allowed */
	qic02_tape_open,		/* open */
	NULL,				/* flush */
	qic02_tape_release,		/* release */
	NULL,				/* fsync */
	NULL,				/* fasync */
	NULL,				/* check_media_change */
	NULL				/* revalidate */
};


/* Why is this not is one place? */
/* Pure 2^n version of get_order */
static inline int __get_order(unsigned long size)
{
    int order;

    size = (size-1) >> (PAGE_SHIFT-1);
    order = -1;
    do
    {
	size >>= 1;
	order++;
    } while (size);
    return order;
}


static void qic02_release_resources(void)
{
    free_irq(QIC02_TAPE_IRQ, NULL);
    free_dma(QIC02_TAPE_DMA);
    release_region(QIC02_TAPE_PORT, QIC02_TAPE_PORT_RANGE);
    if (buffaddr)
    {
	free_pages(buffaddr, __get_order(TPQBUF_SIZE));
    }
    buffaddr = 0; /* Better to cause a panic than overwite someone else */
    status_zombie = YES;
} /* qic02_release_resources */


static int qic02_get_resources(void)
{
    /* First perform some checks. If one of them fails,
     * the tape driver will not be registered to the system.
     */
    if (QIC02_TAPE_IRQ>16)
    {
	tpqputs(TPQD_ALWAYS, "Bogus interrupt number.");
	return -ENXIO;
    }

    /* for DYNCONF, allocating IO, DMA and IRQ should not be done until 
     * the config parameters have been set using MTSETCONFIG.
     */

    if (check_region(QIC02_TAPE_PORT, QIC02_TAPE_PORT_RANGE))
    {
	printk(TPQIC02_NAME ": IO space at 0x%x [%d ports] already reserved\n",
	       QIC02_TAPE_PORT, QIC02_TAPE_PORT_RANGE);
	return -ENXIO;
    }

    /* get IRQ */
    if (request_irq(QIC02_TAPE_IRQ, qic02_tape_interrupt, SA_INTERRUPT, "QIC-02", NULL))
    {
	printk(TPQIC02_NAME ": can't allocate IRQ%d for QIC-02 tape\n",
	       QIC02_TAPE_IRQ);
	return -EBUSY;
    }

    /* After IRQ, allocate DMA channel */
    if (request_dma(QIC02_TAPE_DMA,"QIC-02"))
    {
	printk(TPQIC02_NAME ": can't allocate DMA%d for QIC-02 tape\n",
	       QIC02_TAPE_DMA);
	free_irq(QIC02_TAPE_IRQ, NULL);
	return -EBUSY;
    }

    /* Grab the IO region. We already made sure it's available. */
    request_region(QIC02_TAPE_PORT, QIC02_TAPE_PORT_RANGE, TPQIC02_NAME);
    
    /* Setup the page-address for the dma transfer. */

    /*** TODO: does _get_dma_pages() really return the physical address?? ****/
    buffaddr = __get_dma_pages(GFP_KERNEL,__get_order(TPQBUF_SIZE));
    
    if (!buffaddr)
    {
	qic02_release_resources();
	return -EBUSY; /* Not ideal, EAGAIN perhaps? */
    }
    
    memset( (void*) buffaddr, 0, TPQBUF_SIZE );
    
    printk(TPQIC02_NAME ": Settings: IRQ %d, DMA %d, IO 0x%x, IFC %s\n",
	   QIC02_TAPE_IRQ, QIC02_TAPE_DMA,
	   ((QIC02_TAPE_IFC==ARCHIVE) || (QIC02_TAPE_IFC==MOUNTAIN))?
	   QIC02_CMD_PORT : QIC02_STAT_PORT,
	   (QIC02_TAPE_IFC==MOUNTAIN)? "Mountain" :
	   ((QIC02_TAPE_IFC==ARCHIVE)? "Archive" : "Wangtek"));
    
    if (tape_reset(0)!=TE_OK || tp_sense(TP_WRP|TP_POR|TP_CNI)!=TE_OK)
    {
	/* No drive detected, so vanish */
	tpqputs(TPQD_ALWAYS, "No drive detected -- releasing IO/IRQ/DMA.");
	status_dead = YES;
	qic02_release_resources();
	return -EIO;
    }

    /* All should be ok now */
    status_zombie = NO;
    return 0;
} /* qic02_get_resources */

__initfunc(int qic02_tape_init(void))
{
    if (TPSTATSIZE != 6)
    {
	printk(TPQIC02_NAME ": internal error: tpstatus struct incorrect!\n");
	return -ENODEV;
    }
    if ((TPQBUF_SIZE<512) || (TPQBUF_SIZE>=0x10000))
    {
	printk(TPQIC02_NAME ": internal error: DMA buffer size out of range\n");
	return -ENODEV;
    }

    current_tape_dev = MKDEV(QIC02_TAPE_MAJOR, 0);

#ifndef CONFIG_QIC02_DYNCONF
    printk(TPQIC02_NAME ": IRQ %d, DMA %d, IO 0x%x, IFC %s, %s, %s\n",
	   QIC02_TAPE_IRQ, QIC02_TAPE_DMA,
# if QIC02_TAPE_IFC == WANGTEK
	   QIC02_STAT_PORT, "Wangtek",
# elif QIC02_TAPE_IFC == ARCHIVE
	   QIC02_CMD_PORT, "Archive",
# elif QIC02_TAPE_IFC == MOUNTAIN
	   QIC02_CMD_PORT, "Mountain",
# else
#  error
# endif
	   rcs_revision, rcs_date);
    if (qic02_get_resources())
    {
	return -ENODEV;
    }
#else
    printk(TPQIC02_NAME ": Runtime config, %s, %s\n", 
	   rcs_revision, rcs_date);
#endif
    printk(TPQIC02_NAME ": DMA buffers: %u blocks\n", NR_BLK_BUF);
    /* If we got this far, install driver functions */
    if (register_chrdev(QIC02_TAPE_MAJOR, TPQIC02_NAME, &qic02_tape_fops))
    {
	printk(TPQIC02_NAME ": Unable to get chrdev major %d\n", QIC02_TAPE_MAJOR);
#ifndef CONFIG_QIC02_DYNCONF
	qic02_release_resources();
#endif
	return -ENODEV;
    }

    /* prepare timer */
    TIMEROFF;
    timer_table[QIC02_TAPE_TIMER].expires = 0;
    timer_table[QIC02_TAPE_TIMER].fn = qic02_tape_times_out;
    
#ifndef CONFIG_QIC02_DYNCONF
    if (tape_reset(0)!=TE_OK || tp_sense(TP_WRP|TP_POR|TP_CNI)!=TE_OK)
    {
	/* No drive detected, so vanish */
	tpqputs(TPQD_ALWAYS, "No drive detected -- driver going on vacation...");
	qic02_release_resources();
	status_dead = YES;
	return -ENODEV;
    }
    else
    {
	if (is_exception())
	{
	    tpqputs(TPQD_ALWAYS, "exception detected\n");
	    (void) tp_sense(TP_WRP|TP_POR|TP_CNI);
	}
    }
#endif

    /* initialize generic status for ioctl requests */
    
    ioctl_status.mt_type	= QIC02_TAPE_DRIVE;	/* MT_IS* id nr */
    
    ioctl_status.mt_resid	= 0;	/* ---residual count */
    ioctl_status.mt_gstat	= 0;	/* ---generic status */
    ioctl_status.mt_erreg	= 0;	/* not used */
    ioctl_status.mt_fileno	= 0;	/* number of current file on tape */
    ioctl_status.mt_blkno	= 0;	/* number of current (logical) block */

    return 0;
} /* qic02_tape_init */

#ifdef MODULE

void cleanup_module(void)
{
    if (status_zombie == NO)
    {
	qic02_release_resources();
    }
    unregister_chrdev(QIC02_TAPE_MAJOR, TPQIC02_NAME);
}

int init_module(void)
{
    int retval;
    retval=qic02_tape_init();
# ifdef CONFIG_QIC02_DYNCONF
    /* This allows the dynamic config program to setup the card
     * by presetting qic02_tape_dynconf via insmod
     */
    if (!retval && qic02_tape_dynconf.ifc_type)
    {
	retval=update_ifc_masks(qic02_tape_dynconf.ifc_type);
	if (retval)
	{
	  cleanup_module();
	}
    }
# endif
    return retval;
}
#endif