Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   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
/*	$NetBSD: aic6360.c,v 1.107 2023/05/10 00:10:35 riastradh Exp $	*/

/*
 * Copyright (c) 1994, 1995, 1996 Charles M. Hannum.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Charles M. Hannum.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Copyright (c) 1994 Jarle Greipsland
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Acknowledgements: Many of the algorithms used in this driver are
 * inspired by the work of Julian Elischer (julian@tfs.com) and
 * Charles Hannum (mycroft@duality.gnu.ai.mit.edu).  Thanks a million!
 */

/* TODO list:
 * 1) Get the DMA stuff working.
 * 2) Get the iov/uio stuff working. Is this a good thing ???
 * 3) Get the synch stuff working.
 * 4) Rewrite it to use malloc for the acb structs instead of static alloc.?
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: aic6360.c,v 1.107 2023/05/10 00:10:35 riastradh Exp $");

#include "opt_ddb.h"

/*
 * A few customizable items:
 */

/* Use doubleword transfers to/from SCSI chip.  Note: This requires
 * motherboard support.  Basically, some motherboard chipsets are able to
 * split a 32 bit I/O operation into two 16 bit I/O operations,
 * transparently to the processor.  This speeds up some things, notably long
 * data transfers.
 */
#define AIC_USE_DWORDS		0

/* Synchronous data transfers? */
#define AIC_USE_SYNCHRONOUS	0
#define AIC_SYNC_REQ_ACK_OFS 	8

/* Wide data transfers? */
#define	AIC_USE_WIDE		0
#define	AIC_MAX_WIDTH		0

/* Max attempts made to transmit a message */
#define AIC_MSG_MAX_ATTEMPT	3 /* Not used now XXX */

/* Use DMA (else we do programmed I/O using string instructions) (not yet!)*/
#define AIC_USE_EISA_DMA	0
#define AIC_USE_ISA_DMA		0

/* How to behave on the (E)ISA bus when/if DMAing (on<<4) + off in us */
#define EISA_BRST_TIM ((15<<4) + 1)	/* 15us on, 1us off */

/* Some spin loop parameters (essentially how long to wait some places)
 * The problem(?) is that sometimes we expect either to be able to transmit a
 * byte or to get a new one from the SCSI bus pretty soon.  In order to avoid
 * returning from the interrupt just to get yanked back for the next byte we
 * may spin in the interrupt routine waiting for this byte to come.  How long?
 * This is really (SCSI) device and processor dependent.  Tuneable, I guess.
 */
#define AIC_MSGIN_SPIN		1 	/* Will spinwait upto ?ms for a new msg byte */
#define AIC_MSGOUT_SPIN		1

/* Include debug functions?  At the end of this file there are a bunch of
 * functions that will print out various information regarding queued SCSI
 * commands, driver state and chip contents.  You can call them from the
 * kernel debugger.  If you set AIC_DEBUG to 0 they are not included (the
 * kernel uses less memory) but you lose the debugging facilities.
 */
#define AIC_DEBUG		1

#define	AIC_ABORT_TIMEOUT	2000	/* time to wait for abort */

/* End of customizable parameters */

#if AIC_USE_EISA_DMA || AIC_USE_ISA_DMA
#error "I said not yet! Start paying attention... grumble"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/queue.h>

#include <sys/bus.h>
#include <sys/intr.h>

#include <dev/scsipi/scsi_spc.h>
#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsi_message.h>
#include <dev/scsipi/scsiconf.h>

#include <dev/ic/aic6360reg.h>
#include <dev/ic/aic6360var.h>

#include "ioconf.h"

#ifndef DDB
#define	Debugger() panic("should call debugger here (aic6360.c)")
#endif /* ! DDB */

#if AIC_DEBUG
int aic_debug = 0x00; /* AIC_SHOWSTART|AIC_SHOWMISC|AIC_SHOWTRACE; */
#endif

static void	aic_minphys(struct buf *);
static void	aic_done(struct aic_softc *, struct aic_acb *);
static void	aic_dequeue(struct aic_softc *, struct aic_acb *);
static void	aic_scsipi_request(struct scsipi_channel *,
				   scsipi_adapter_req_t, void *);
static int	aic_poll(struct aic_softc *, struct scsipi_xfer *, int);
static void	aic_select(struct aic_softc *, struct aic_acb *);
static void	aic_timeout(void *);
static void	aic_sched(struct aic_softc *);
static void	aic_scsi_reset(struct aic_softc *);
static void	aic_reset(struct aic_softc *);
static void	aic_free_acb(struct aic_softc *, struct aic_acb *);
static struct aic_acb* aic_get_acb(struct aic_softc *);
static int	aic_reselect(struct aic_softc *, int);
static void	aic_sense(struct aic_softc *, struct aic_acb *);
static void	aic_msgin(struct aic_softc *);
static void	aic_abort(struct aic_softc *, struct aic_acb *);
static void	aic_msgout(struct aic_softc *);
static int	aic_dataout_pio(struct aic_softc *, u_char *, int);
static int	aic_datain_pio(struct aic_softc *, u_char *, int);
static void	aic_update_xfer_mode(struct aic_softc *, int);
#if AIC_DEBUG
static void	aic_print_acb(struct aic_acb *);
void	aic_dump_driver(struct aic_softc *);
void	aic_dump6360(struct aic_softc *);
static void	aic_show_scsi_cmd(struct aic_acb *);
void	aic_print_active_acb(void);
#endif

/*
 * INITIALIZATION ROUTINES (probe, attach ++)
 */

/* Do the real search-for-device.
 * Prerequisite: sc->sc_iobase should be set to the proper value
 */
int
aic_find(bus_space_tag_t iot, bus_space_handle_t ioh)
{
	char chip_id[sizeof(IDSTRING)];	/* For chips that support it */
	int i;

	/* Remove aic6360 from possible powerdown mode */
	bus_space_write_1(iot, ioh, DMACNTRL0, 0);

	/* Thanks to mark@aggregate.com for the new method for detecting
	 * whether the chip is present or not.  Bonus: may also work for
	 * the AIC-6260!
 	 */
	AIC_TRACE(("aic: probing for aic-chip\n"));
 	/*
 	 * Linux also init's the stack to 1-16 and then clears it,
     	 *  6260's don't appear to have an ID reg - mpg
 	 */
	/* Push the sequence 0,1,..,15 on the stack */
#define STSIZE 16
	bus_space_write_1(iot, ioh, DMACNTRL1, 0); /* Reset stack pointer */
	for (i = 0; i < STSIZE; i++)
		bus_space_write_1(iot, ioh, STACK, i);

	/* See if we can pull out the same sequence */
	bus_space_write_1(iot, ioh, DMACNTRL1, 0);
 	for (i = 0; i < STSIZE && bus_space_read_1(iot, ioh, STACK) == i; i++)
		;
	if (i != STSIZE) {
		AIC_START(("STACK futzed at %d.\n", i));
		return 0;
	}

	/* See if we can pull the id string out of the ID register,
	 * now only used for informational purposes.
	 */
	memset(chip_id, 0, sizeof(chip_id));
	bus_space_read_multi_1(iot, ioh, ID, chip_id, sizeof(IDSTRING) - 1);
	AIC_START(("AIC found ID: %s ",chip_id));
	AIC_START(("chip revision %d\n",
	    (int)bus_space_read_1(iot, ioh, REV)));

	return 1;
}

/*
 * Attach the AIC6360, fill out some high and low level data structures
 */
void
aicattach(struct aic_softc *sc)
{
	struct scsipi_adapter *adapt = &sc->sc_adapter;
	struct scsipi_channel *chan = &sc->sc_channel;

	AIC_TRACE(("aicattach  "));
	sc->sc_state = AIC_INIT;

	sc->sc_initiator = 7;
	sc->sc_freq = 20;	/* XXXX Assume 20 MHz. */

	/*
	 * These are the bounds of the sync period, based on the frequency of
	 * the chip's clock input and the size and offset of the sync period
	 * register.
	 *
	 * For a 20MHz clock, this gives us 25, or 100nS, or 10MB/s, as a
	 * maximum transfer rate, and 112.5, or 450nS, or 2.22MB/s, as a
	 * minimum transfer rate.
	 */
	sc->sc_minsync = (2 * 250) / sc->sc_freq;
	sc->sc_maxsync = (9 * 250) / sc->sc_freq;

	/*
	 * Fill in the scsipi_adapter.
	 */
	adapt->adapt_dev = sc->sc_dev;
	adapt->adapt_nchannels = 1;
	adapt->adapt_openings = 8;
	adapt->adapt_max_periph = 1;
	adapt->adapt_request = aic_scsipi_request;
	adapt->adapt_minphys = aic_minphys;

	/*
	 * Fill in the scsipi_channel.
	 */
	chan->chan_adapter = adapt;
	chan->chan_bustype = &scsi_bustype;
	chan->chan_channel = 0;
	chan->chan_ntargets = 8;
	chan->chan_nluns = 8;
	chan->chan_id = sc->sc_initiator;

	/*
	 * Add reference to adapter so that we drop the reference after
	 * config_found() to make sure the adapter is disabled.
	 */
	if (scsipi_adapter_addref(adapt) != 0) {
		aprint_error_dev(sc->sc_dev, "unable to enable controller\n");
		return;
	}

	aic_init(sc, 1);	/* Init chip and driver */

	/*
	 * Ask the adapter what subunits are present
	 */
	sc->sc_child = config_found(sc->sc_dev, &sc->sc_channel, scsiprint,
	    CFARGS_NONE);
	scsipi_adapter_delref(adapt);
}

int
aic_detach(device_t self, int flags)
{
	int error;

	error = config_detach_children(self, flags);
	if (error)
		return error;

	return 0;
}

/* Initialize AIC6360 chip itself
 * The following conditions should hold:
 * aic_isa_probe should have succeeded, i.e. the iobase address in aic_softc
 * must be valid.
 */
static void
aic_reset(struct aic_softc *sc)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	/*
	 * Doc. recommends to clear these two registers before
	 * operations commence
	 */
	bus_space_write_1(iot, ioh, SCSITEST, 0);
	bus_space_write_1(iot, ioh, TEST, 0);

	/* Reset SCSI-FIFO and abort any transfers */
	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | CLRCH | CLRSTCNT);

	/* Reset DMA-FIFO */
	bus_space_write_1(iot, ioh, DMACNTRL0, RSTFIFO);
	bus_space_write_1(iot, ioh, DMACNTRL1, 0);

	/* Disable all selection features */
	bus_space_write_1(iot, ioh, SCSISEQ, 0);
	bus_space_write_1(iot, ioh, SXFRCTL1, 0);

	/* Disable some interrupts */
	bus_space_write_1(iot, ioh, SIMODE0, 0x00);
	/* Clear a slew of interrupts */
	bus_space_write_1(iot, ioh, CLRSINT0, 0x7f);

	/* Disable some more interrupts */
	bus_space_write_1(iot, ioh, SIMODE1, 0x00);
	/* Clear another slew of interrupts */
	bus_space_write_1(iot, ioh, CLRSINT1, 0xef);

	/* Disable synchronous transfers */
	bus_space_write_1(iot, ioh, SCSIRATE, 0);

	/* Haven't seen ant errors (yet) */
	bus_space_write_1(iot, ioh, CLRSERR, 0x07);

	/* Set our SCSI-ID */
	bus_space_write_1(iot, ioh, SCSIID, sc->sc_initiator << OID_S);
	bus_space_write_1(iot, ioh, BRSTCNTRL, EISA_BRST_TIM);
}

/* Pull the SCSI RST line for 500 us */
static void
aic_scsi_reset(struct aic_softc *sc)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	bus_space_write_1(iot, ioh, SCSISEQ, SCSIRSTO);
	delay(500);
	bus_space_write_1(iot, ioh, SCSISEQ, 0);
	delay(50);
}

/*
 * Initialize aic SCSI driver.
 */
void
aic_init(struct aic_softc *sc, int bus_reset)
{
	struct aic_acb *acb;
	int r;

	if (bus_reset) {
		aic_reset(sc);
		aic_scsi_reset(sc);
	}
	aic_reset(sc);

	if (sc->sc_state == AIC_INIT) {
		/* First time through; initialize. */
		TAILQ_INIT(&sc->ready_list);
		TAILQ_INIT(&sc->nexus_list);
		TAILQ_INIT(&sc->free_list);
		sc->sc_nexus = NULL;
		acb = sc->sc_acb;
		memset(acb, 0, sizeof(sc->sc_acb));
		for (r = 0; r < sizeof(sc->sc_acb) / sizeof(*acb); r++) {
			TAILQ_INSERT_TAIL(&sc->free_list, acb, chain);
			acb++;
		}
		memset(&sc->sc_tinfo, 0, sizeof(sc->sc_tinfo));
	} else {
		/* Cancel any active commands. */
		sc->sc_state = AIC_CLEANING;
		if ((acb = sc->sc_nexus) != NULL) {
			acb->xs->error = XS_DRIVER_STUFFUP;
			callout_stop(&acb->xs->xs_callout);
			aic_done(sc, acb);
		}
		while ((acb = sc->nexus_list.tqh_first) != NULL) {
			acb->xs->error = XS_DRIVER_STUFFUP;
			callout_stop(&acb->xs->xs_callout);
			aic_done(sc, acb);
		}
	}

	sc->sc_prevphase = PH_INVALID;
	for (r = 0; r < 8; r++) {
		struct aic_tinfo *ti = &sc->sc_tinfo[r];

		ti->flags = 0;
		ti->period = ti->offset = 0;
		ti->width = 0;
	}

	sc->sc_state = AIC_IDLE;
	bus_space_write_1(sc->sc_iot, sc->sc_ioh, DMACNTRL0, INTEN);
}

static void
aic_free_acb(struct aic_softc *sc, struct aic_acb *acb)
{
	int s;

	s = splbio();
	acb->flags = 0;
	TAILQ_INSERT_HEAD(&sc->free_list, acb, chain);
	splx(s);
}

static struct aic_acb *
aic_get_acb(struct aic_softc *sc)
{
	struct aic_acb *acb;
	int s;

	s = splbio();
	acb = TAILQ_FIRST(&sc->free_list);
	if (acb != NULL) {
		TAILQ_REMOVE(&sc->free_list, acb, chain);
		acb->flags |= ACB_ALLOC;
	}
	splx(s);
	return (acb);
}

/*
 * DRIVER FUNCTIONS CALLABLE FROM HIGHER LEVEL DRIVERS
 */

/*
 * Expected sequence:
 * 1) Command inserted into ready list
 * 2) Command selected for execution
 * 3) Command won arbitration and has selected target device
 * 4) Send message out (identify message, eventually also sync.negotiations)
 * 5) Send command
 * 5a) Receive disconnect message, disconnect.
 * 5b) Reselected by target
 * 5c) Receive identify message from target.
 * 6) Send or receive data
 * 7) Receive status
 * 8) Receive message (command complete etc.)
 * 9) If status == SCSI_CHECK construct a synthetic request sense SCSI cmd.
 *    Repeat 2-8 (no disconnects please...)
 */

/*
 * Perform a request from the SCSIPI midlayer.
 */
static void
aic_scsipi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
    void *arg)
{
	struct scsipi_xfer *xs;
	struct scsipi_periph *periph;
	struct aic_softc *sc = device_private(chan->chan_adapter->adapt_dev);
	struct aic_acb *acb;
	int s, flags;

	AIC_TRACE(("aic_request  "));

	switch (req) {
	case ADAPTER_REQ_RUN_XFER:
		xs = arg;
		periph = xs->xs_periph;

		AIC_CMDS(("[0x%x, %d]->%d ", (int)xs->cmd->opcode, xs->cmdlen,
		    periph->periph_target));

		if (!device_is_active(sc->sc_dev)) {
			xs->error = XS_DRIVER_STUFFUP;
			scsipi_done(xs);
			return;
		}

		flags = xs->xs_control;
		acb = aic_get_acb(sc);
#ifdef DIAGNOSTIC
		/*
		 * This should never happen as we track the resources
		 * in the mid-layer.
		 */
		if (acb == NULL) {
			scsipi_printaddr(periph);
			printf("unable to allocate acb\n");
			panic("aic_scsipi_request");
		}
#endif

		/* Initialize acb */
		acb->xs = xs;
		acb->timeout = xs->timeout;

		if (xs->xs_control & XS_CTL_RESET) {
			acb->flags |= ACB_RESET;
			acb->scsipi_cmd_length = 0;
			acb->data_length = 0;
		} else {
			memcpy(&acb->scsipi_cmd, xs->cmd, xs->cmdlen);
			acb->scsipi_cmd_length = xs->cmdlen;
			acb->data_addr = xs->data;
			acb->data_length = xs->datalen;
		}
		acb->target_stat = 0;

		s = splbio();

		TAILQ_INSERT_TAIL(&sc->ready_list, acb, chain);
		if (sc->sc_state == AIC_IDLE)
			aic_sched(sc);

		splx(s);

		if ((flags & XS_CTL_POLL) == 0)
			return;

		/* Not allowed to use interrupts, use polling instead */
		if (aic_poll(sc, xs, acb->timeout)) {
			aic_timeout(acb);
			if (aic_poll(sc, xs, acb->timeout))
				aic_timeout(acb);
		}
		return;

	case ADAPTER_REQ_GROW_RESOURCES:
		/* XXX Not supported. */
		return;

	case ADAPTER_REQ_SET_XFER_MODE:
	    {
		struct aic_tinfo *ti;
		struct scsipi_xfer_mode *xm = arg;

		ti = &sc->sc_tinfo[xm->xm_target];
		ti->flags &= ~(DO_SYNC|DO_WIDE);
		ti->period = 0;
		ti->offset = 0;

#if AIC_USE_SYNCHRONOUS
		if (xm->xm_mode & PERIPH_CAP_SYNC) {
			ti->flags |= DO_SYNC;
			ti->period = sc->sc_minsync;
			ti->offset = AIC_SYNC_REQ_ACK_OFS;
		}
#endif
#if AIC_USE_WIDE
		if (xm->xm_mode & PERIPH_CAP_WIDE16) {
			ti->flags |= DO_WIDE;
			ti->width = AIC_MAX_WIDTH;
		}
#endif
		/*
		 * If we're not going to negotiate, send the notification
		 * now, since it won't happen later.
		 */
		if ((ti->flags & (DO_SYNC|DO_WIDE)) == 0)
			aic_update_xfer_mode(sc, xm->xm_target);
		return;
	    }
	}
}

static void
aic_update_xfer_mode(struct aic_softc *sc, int target)
{
	struct scsipi_xfer_mode xm;
	struct aic_tinfo *ti = &sc->sc_tinfo[target];

	xm.xm_target = target;
	xm.xm_mode = 0;
	xm.xm_period = 0;
	xm.xm_offset = 0;

	if (ti->offset != 0) {
		xm.xm_mode |= PERIPH_CAP_SYNC;
		xm.xm_period = ti->period;
		xm.xm_offset = ti->offset;
	}
	switch (ti->width) {
	case 2:
		xm.xm_mode |= PERIPH_CAP_WIDE32;
		break;
	case 1:
		xm.xm_mode |= PERIPH_CAP_WIDE16;
		break;
	}

	scsipi_async_event(&sc->sc_channel, ASYNC_EVENT_XFER_MODE, &xm);
}

/*
 * Adjust transfer size in buffer structure
 */
static void
aic_minphys(struct buf *bp)
{

	AIC_TRACE(("aic_minphys  "));
	if (bp->b_bcount > (AIC_NSEG << PGSHIFT))
		bp->b_bcount = (AIC_NSEG << PGSHIFT);
	minphys(bp);
}

/*
 * Used when interrupt driven I/O isn't allowed, e.g. during boot.
 */
static int
aic_poll(struct aic_softc *sc, struct scsipi_xfer *xs, int count)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	AIC_TRACE(("aic_poll  "));
	while (count) {
		/*
		 * If we had interrupts enabled, would we
		 * have got an interrupt?
		 */
		if ((bus_space_read_1(iot, ioh, DMASTAT) & INTSTAT) != 0)
			aicintr(sc);
		if ((xs->xs_status & XS_STS_DONE) != 0)
			return 0;
		delay(1000);
		count--;
	}
	return 1;
}

/*
 * LOW LEVEL SCSI UTILITIES
 */

static inline void
aic_sched_msgout(struct aic_softc *sc, u_char m)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	if (sc->sc_msgpriq == 0)
		bus_space_write_1(iot, ioh, SCSISIG, sc->sc_phase | ATNO);
	sc->sc_msgpriq |= m;
}

/*
 * Set synchronous transfer offset and period.
 */
#if !AIC_USE_SYNCHRONOUS
/* ARGSUSED */
#endif
static inline void
aic_setsync(struct aic_softc *sc, struct aic_tinfo *ti)
{
#if AIC_USE_SYNCHRONOUS
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	if (ti->offset != 0)
		bus_space_write_1(iot, ioh, SCSIRATE,
		    ((ti->period * sc->sc_freq) / 250 - 2) << 4 | ti->offset);
	else
		bus_space_write_1(iot, ioh, SCSIRATE, 0);
#endif
}

/*
 * Start a selection.  This is used by aic_sched() to select an idle target,
 * and by aic_done() to immediately reselect a target to get sense information.
 */
static void
aic_select(struct aic_softc *sc, struct aic_acb *acb)
{
	struct scsipi_periph *periph = acb->xs->xs_periph;
	int target = periph->periph_target;
	struct aic_tinfo *ti = &sc->sc_tinfo[target];
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	bus_space_write_1(iot, ioh, SCSIID,
	    sc->sc_initiator << OID_S | target);
	aic_setsync(sc, ti);
	bus_space_write_1(iot, ioh, SXFRCTL1, STIMO_256ms | ENSTIMER);

	/* Always enable reselections. */
	bus_space_write_1(iot, ioh, SIMODE0, ENSELDI | ENSELDO);
	bus_space_write_1(iot, ioh, SIMODE1, ENSCSIRST | ENSELTIMO);
	bus_space_write_1(iot, ioh, SCSISEQ, ENRESELI | ENSELO | ENAUTOATNO);

	sc->sc_state = AIC_SELECTING;
}

static int
aic_reselect(struct aic_softc *sc, int message)
{
	u_char selid, target, lun;
	struct aic_acb *acb;
	struct scsipi_periph *periph;
	struct aic_tinfo *ti;

	/*
	 * The SCSI chip made a snapshot of the data bus while the reselection
	 * was being negotiated.  This enables us to determine which target did
	 * the reselect.
	 */
	selid = sc->sc_selid & ~(1 << sc->sc_initiator);
	if (selid & (selid - 1)) {
		aprint_error_dev(sc->sc_dev,
		    "reselect with invalid selid %02x; "
		    "sending DEVICE RESET\n", selid);
		AIC_BREAK();
		goto reset;
	}

	/* Search wait queue for disconnected cmd
	 * The list should be short, so I haven't bothered with
	 * any more sophisticated structures than a simple
	 * singly linked list.
	 */
	target = ffs(selid) - 1;
	lun = message & 0x07;
	for (acb = sc->nexus_list.tqh_first; acb != NULL;
	     acb = acb->chain.tqe_next) {
		periph = acb->xs->xs_periph;
		if (periph->periph_target == target &&
		    periph->periph_lun == lun)
			break;
	}
	if (acb == NULL) {
		printf("%s: reselect from target %d lun %d with no nexus; "
		    "sending ABORT\n", device_xname(sc->sc_dev), target, lun);
		AIC_BREAK();
		goto abort;
	}

	/* Make this nexus active again. */
	TAILQ_REMOVE(&sc->nexus_list, acb, chain);
	sc->sc_state = AIC_CONNECTED;
	sc->sc_nexus = acb;
	ti = &sc->sc_tinfo[target];
	ti->lubusy |= (1 << lun);
	aic_setsync(sc, ti);

	if (acb->flags & ACB_RESET)
		aic_sched_msgout(sc, SEND_DEV_RESET);
	else if (acb->flags & ACB_ABORT)
		aic_sched_msgout(sc, SEND_ABORT);

	/* Do an implicit RESTORE POINTERS. */
	sc->sc_dp = acb->data_addr;
	sc->sc_dleft = acb->data_length;
	sc->sc_cp = (u_char *)&acb->scsipi_cmd;
	sc->sc_cleft = acb->scsipi_cmd_length;

	return (0);

reset:
	aic_sched_msgout(sc, SEND_DEV_RESET);
	return (1);

abort:
	aic_sched_msgout(sc, SEND_ABORT);
	return (1);
}

/*
 * Schedule a SCSI operation.  This has now been pulled out of the interrupt
 * handler so that we may call it from aic_scsipi_request and aic_done.  This
 * may save us an unnecessary interrupt just to get things going.  Should only
 * be called when state == AIC_IDLE and at bio pl.
 */
static void
aic_sched(struct aic_softc *sc)
{
	struct aic_acb *acb;
	struct scsipi_periph *periph;
	struct aic_tinfo *ti;
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	if (!device_is_active(sc->sc_dev))
		return;

	/*
	 * Find first acb in ready queue that is for a target/lunit pair that
	 * is not busy.
	 */
	bus_space_write_1(iot, ioh, CLRSINT1,
	    CLRSELTIMO | CLRBUSFREE | CLRSCSIPERR);
	for (acb = sc->ready_list.tqh_first; acb != NULL;
	    acb = acb->chain.tqe_next) {
		periph = acb->xs->xs_periph;
		ti = &sc->sc_tinfo[periph->periph_target];
		if ((ti->lubusy & (1 << periph->periph_lun)) == 0) {
			AIC_MISC(("selecting %d:%d  ",
			    periph->periph_target, periph->periph_lun));
			TAILQ_REMOVE(&sc->ready_list, acb, chain);
			sc->sc_nexus = acb;
			aic_select(sc, acb);
			return;
		} else
			AIC_MISC(("%d:%d busy\n",
			    periph->periph_target, periph->periph_lun));
	}
	AIC_MISC(("idle  "));
	/* Nothing to start; just enable reselections and wait. */
	bus_space_write_1(iot, ioh, SIMODE0, ENSELDI);
	bus_space_write_1(iot, ioh, SIMODE1, ENSCSIRST);
	bus_space_write_1(iot, ioh, SCSISEQ, ENRESELI);
}

static void
aic_sense(struct aic_softc *sc, struct aic_acb *acb)
{
	struct scsipi_xfer *xs = acb->xs;
	struct scsipi_periph *periph = xs->xs_periph;
	struct aic_tinfo *ti = &sc->sc_tinfo[periph->periph_target];
	struct scsi_request_sense *ss = (void *)&acb->scsipi_cmd;

	AIC_MISC(("requesting sense  "));
	/* Next, setup a request sense command block */
	memset(ss, 0, sizeof(*ss));
	ss->opcode = SCSI_REQUEST_SENSE;
	ss->byte2 = periph->periph_lun << 5;
	ss->length = sizeof(struct scsi_sense_data);
	acb->scsipi_cmd_length = sizeof(*ss);
	acb->data_addr = (char *)&xs->sense.scsi_sense;
	acb->data_length = sizeof(struct scsi_sense_data);
	acb->flags |= ACB_SENSE;
	ti->senses++;
	if (acb->flags & ACB_NEXUS)
		ti->lubusy &= ~(1 << periph->periph_lun);
	if (acb == sc->sc_nexus) {
		aic_select(sc, acb);
	} else {
		aic_dequeue(sc, acb);
		TAILQ_INSERT_HEAD(&sc->ready_list, acb, chain);
		if (sc->sc_state == AIC_IDLE)
			aic_sched(sc);
	}
}

/*
 * POST PROCESSING OF SCSI_CMD (usually current)
 */
static void
aic_done(struct aic_softc *sc, struct aic_acb *acb)
{
	struct scsipi_xfer *xs = acb->xs;
	struct scsipi_periph *periph = xs->xs_periph;
	struct aic_tinfo *ti = &sc->sc_tinfo[periph->periph_target];

	AIC_TRACE(("aic_done  "));

	/*
	 * Now, if we've come here with no error code, i.e. we've kept the
	 * initial XS_NOERROR, and the status code signals that we should
	 * check sense, we'll need to set up a request sense cmd block and
	 * push the command back into the ready queue *before* any other
	 * commands for this target/lunit, else we lose the sense info.
	 * We don't support chk sense conditions for the request sense cmd.
	 */
	if (xs->error == XS_NOERROR) {
		if (acb->flags & ACB_ABORT) {
			xs->error = XS_DRIVER_STUFFUP;
		} else if (acb->flags & ACB_SENSE) {
			xs->error = XS_SENSE;
		} else if (acb->target_stat == SCSI_CHECK) {
			/* First, save the return values */
			xs->resid = acb->data_length;
			xs->status = acb->target_stat;
			aic_sense(sc, acb);
			return;
		} else {
			xs->resid = acb->data_length;
		}
	}

#if AIC_DEBUG
	if ((aic_debug & AIC_SHOWMISC) != 0) {
		if (xs->resid != 0)
			printf("resid=%d ", xs->resid);
		if (xs->error == XS_SENSE)
			printf("sense=0x%02x\n", xs->sense.scsi_sense.response_code);
		else
			printf("error=%d\n", xs->error);
	}
#endif

	/*
	 * Remove the ACB from whatever queue it happens to be on.
	 */
	if (acb->flags & ACB_NEXUS)
		ti->lubusy &= ~(1 << periph->periph_lun);
	if (acb == sc->sc_nexus) {
		sc->sc_nexus = NULL;
		sc->sc_state = AIC_IDLE;
		aic_sched(sc);
	} else
		aic_dequeue(sc, acb);

	aic_free_acb(sc, acb);
	ti->cmds++;
	scsipi_done(xs);
}

static void
aic_dequeue(struct aic_softc *sc, struct aic_acb *acb)
{

	if (acb->flags & ACB_NEXUS) {
		TAILQ_REMOVE(&sc->nexus_list, acb, chain);
	} else {
		TAILQ_REMOVE(&sc->ready_list, acb, chain);
	}
}

/*
 * INTERRUPT/PROTOCOL ENGINE
 */

/*
 * Precondition:
 * The SCSI bus is already in the MSGI phase and there is a message byte
 * on the bus, along with an asserted REQ signal.
 */
static void
aic_msgin(struct aic_softc *sc)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
	u_char sstat1;
	int n;

	AIC_TRACE(("aic_msgin  "));

	if (sc->sc_prevphase == PH_MSGIN) {
		/* This is a continuation of the previous message. */
		n = sc->sc_imp - sc->sc_imess;
		goto nextbyte;
	}

	/* This is a new MESSAGE IN phase.  Clean up our state. */
	sc->sc_flags &= ~AIC_DROP_MSGIN;

nextmsg:
	n = 0;
	sc->sc_imp = &sc->sc_imess[n];

nextbyte:
	/*
	 * Read a whole message, but don't ack the last byte.  If we reject the
	 * message, we have to assert ATN during the message transfer phase
	 * itself.
	 */
	for (;;) {
		for (;;) {
			sstat1 = bus_space_read_1(iot, ioh, SSTAT1);
			if ((sstat1 & (REQINIT | PHASECHG | BUSFREE)) != 0)
				break;
			/* Wait for REQINIT.  XXX Need timeout. */
		}
		if ((sstat1 & (PHASECHG | BUSFREE)) != 0) {
			/*
			 * Target left MESSAGE IN, probably because it
			 * a) noticed our ATN signal, or
			 * b) ran out of messages.
			 */
			goto out;
		}

		/* If parity error, just dump everything on the floor. */
		if ((sstat1 & SCSIPERR) != 0) {
			sc->sc_flags |= AIC_DROP_MSGIN;
			aic_sched_msgout(sc, SEND_PARITY_ERROR);
		}

		/* Gather incoming message bytes if needed. */
		if ((sc->sc_flags & AIC_DROP_MSGIN) == 0) {
			if (n >= AIC_MAX_MSG_LEN) {
				(void) bus_space_read_1(iot, ioh, SCSIDAT);
				sc->sc_flags |= AIC_DROP_MSGIN;
				aic_sched_msgout(sc, SEND_REJECT);
			} else {
				*sc->sc_imp++ = bus_space_read_1(iot, ioh,
				    SCSIDAT);
				n++;
				/*
				 * This testing is suboptimal, but most
				 * messages will be of the one byte variety, so
				 * it should not affect performance
				 * significantly.
				 */
				if (n == 1 && MSG_IS1BYTE(sc->sc_imess[0]))
					break;
				if (n == 2 && MSG_IS2BYTE(sc->sc_imess[0]))
					break;
				if (n >= 3 && MSG_ISEXTENDED(sc->sc_imess[0]) &&
				    n == sc->sc_imess[1] + 2)
					break;
			}
		} else
			(void) bus_space_read_1(iot, ioh, SCSIDAT);

		/*
		 * If we reach this spot we're either:
		 * a) in the middle of a multi-byte message, or
		 * b) dropping bytes.
		 */
		bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | SPIOEN);
		/* Ack the last byte read. */
		(void) bus_space_read_1(iot, ioh, SCSIDAT);
		bus_space_write_1(iot, ioh, SXFRCTL0, CHEN);
		while ((bus_space_read_1(iot, ioh, SCSISIG) & ACKI) != 0)
			;
	}

	AIC_MISC(("n=%d imess=0x%02x  ", n, sc->sc_imess[0]));

	/* We now have a complete message.  Parse it. */
	switch (sc->sc_state) {
		struct aic_acb *acb;
		struct aic_tinfo *ti;

	case AIC_CONNECTED:
		AIC_ASSERT(sc->sc_nexus != NULL);
		acb = sc->sc_nexus;
		ti = &sc->sc_tinfo[acb->xs->xs_periph->periph_target];

		switch (sc->sc_imess[0]) {
		case MSG_CMDCOMPLETE:
#if 0
			/* impossible dleft is unsigned */
			if (sc->sc_dleft < 0) {
				periph = acb->xs->xs_periph;
				printf("%s: %ld extra bytes from %d:%d\n",
				    device_xname(sc->sc_dev),
				    (long)-sc->sc_dleft,
				    periph->periph_target, periph->periph_lun);
				sc->sc_dleft = 0;
			}
#endif
			acb->xs->resid = acb->data_length = sc->sc_dleft;
			sc->sc_state = AIC_CMDCOMPLETE;
			break;

		case MSG_PARITY_ERROR:
			/* Resend the last message. */
			aic_sched_msgout(sc, sc->sc_lastmsg);
			break;

		case MSG_MESSAGE_REJECT:
			AIC_MISC(("message rejected %02x  ", sc->sc_lastmsg));
			switch (sc->sc_lastmsg) {
#if AIC_USE_SYNCHRONOUS + AIC_USE_WIDE
			case SEND_IDENTIFY:
				ti->flags &= ~(DO_SYNC | DO_WIDE);
				ti->period = ti->offset = 0;
				aic_setsync(sc, ti);
				ti->width = 0;
				break;
#endif
#if AIC_USE_SYNCHRONOUS
			case SEND_SDTR:
				ti->flags &= ~DO_SYNC;
				ti->period = ti->offset = 0;
				aic_setsync(sc, ti);
				aic_update_xfer_mode(sc,
				    acb->xs->xs_periph->periph_target);
				break;
#endif
#if AIC_USE_WIDE
			case SEND_WDTR:
				ti->flags &= ~DO_WIDE;
				ti->width = 0;
				aic_update_xfer_mode(sc,
				    acb->xs->xs_periph->periph_target);
				break;
#endif
			case SEND_INIT_DET_ERR:
				aic_sched_msgout(sc, SEND_ABORT);
				break;
			}
			break;

		case MSG_NOOP:
			break;

		case MSG_DISCONNECT:
			ti->dconns++;
			sc->sc_state = AIC_DISCONNECT;
			break;

		case MSG_SAVEDATAPOINTER:
			acb->data_addr = sc->sc_dp;
			acb->data_length = sc->sc_dleft;
			break;

		case MSG_RESTOREPOINTERS:
			sc->sc_dp = acb->data_addr;
			sc->sc_dleft = acb->data_length;
			sc->sc_cp = (u_char *)&acb->scsipi_cmd;
			sc->sc_cleft = acb->scsipi_cmd_length;
			break;

		case MSG_EXTENDED:
			switch (sc->sc_imess[2]) {
#if AIC_USE_SYNCHRONOUS
			case MSG_EXT_SDTR:
				if (sc->sc_imess[1] != 3)
					goto reject;
				ti->period = sc->sc_imess[3];
				ti->offset = sc->sc_imess[4];
				ti->flags &= ~DO_SYNC;
				if (ti->offset == 0) {
				} else if (ti->period < sc->sc_minsync ||
					   ti->period > sc->sc_maxsync ||
					   ti->offset > 8) {
					ti->period = ti->offset = 0;
					aic_sched_msgout(sc, SEND_SDTR);
				} else {
					aic_update_xfer_mode(sc,
					    acb->xs->xs_periph->periph_target);
				}
				aic_setsync(sc, ti);
				break;
#endif

#if AIC_USE_WIDE
			case MSG_EXT_WDTR:
				if (sc->sc_imess[1] != 2)
					goto reject;
				ti->width = sc->sc_imess[3];
				ti->flags &= ~DO_WIDE;
				if (ti->width == 0) {
				} else if (ti->width > AIC_MAX_WIDTH) {
					ti->width = 0;
					aic_sched_msgout(sc, SEND_WDTR);
				} else {
					aic_update_xfer_mode(sc,
					    acb->xs->xs_periph->periph_target);
				}
				break;
#endif

			default:
				printf("%s: unrecognized MESSAGE EXTENDED; "
				    "sending REJECT\n",
				    device_xname(sc->sc_dev));
				AIC_BREAK();
				goto reject;
			}
			break;

		default:
			printf("%s: unrecognized MESSAGE; sending REJECT\n",
			    device_xname(sc->sc_dev));
			AIC_BREAK();
		reject:
			aic_sched_msgout(sc, SEND_REJECT);
			break;
		}
		break;

	case AIC_RESELECTED:
		if (!MSG_ISIDENTIFY(sc->sc_imess[0])) {
			printf("%s: reselect without IDENTIFY; "
			    "sending DEVICE RESET\n", device_xname(sc->sc_dev));
			AIC_BREAK();
			goto reset;
		}

		(void) aic_reselect(sc, sc->sc_imess[0]);
		break;

	default:
		aprint_error_dev(sc->sc_dev,
		    "unexpected MESSAGE IN; sending DEVICE RESET\n");
		AIC_BREAK();
	reset:
		aic_sched_msgout(sc, SEND_DEV_RESET);
		break;

#ifdef notdef
	abort:
		aic_sched_msgout(sc, SEND_ABORT);
		break;
#endif
	}

	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | SPIOEN);
	/* Ack the last message byte. */
	(void) bus_space_read_1(iot, ioh, SCSIDAT);
	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN);
	while ((bus_space_read_1(iot, ioh, SCSISIG) & ACKI) != 0)
		;

	/* Go get the next message, if any. */
	goto nextmsg;

out:
	AIC_MISC(("n=%d imess=0x%02x  ", n, sc->sc_imess[0]));
}

/*
 * Send the highest priority, scheduled message.
 */
static void
aic_msgout(struct aic_softc *sc)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
#if AIC_USE_SYNCHRONOUS
	struct aic_tinfo *ti;
#endif
	u_char sstat1;
	int n;

	AIC_TRACE(("aic_msgout  "));

	/* Reset the FIFO. */
	bus_space_write_1(iot, ioh, DMACNTRL0, RSTFIFO);
	/* Enable REQ/ACK protocol. */
	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | SPIOEN);

	if (sc->sc_prevphase == PH_MSGOUT) {
		if (sc->sc_omp == sc->sc_omess) {
			/*
			 * This is a retransmission.
			 *
			 * We get here if the target stayed in MESSAGE OUT
			 * phase.  Section 5.1.9.2 of the SCSI 2 spec indicates
			 * that all of the previously transmitted messages must
			 * be sent again, in the same order.  Therefore, we
			 * requeue all the previously transmitted messages, and
			 * start again from the top.  Our simple priority
			 * scheme keeps the messages in the right order.
			 */
			AIC_MISC(("retransmitting  "));
			sc->sc_msgpriq |= sc->sc_msgoutq;
			/*
			 * Set ATN.  If we're just sending a trivial 1-byte
			 * message, we'll clear ATN later on anyway.
			 */
			bus_space_write_1(iot, ioh, SCSISIG, PH_MSGOUT | ATNO);
		} else {
			/* This is a continuation of the previous message. */
			n = sc->sc_omp - sc->sc_omess;
			goto nextbyte;
		}
	}

	/* No messages transmitted so far. */
	sc->sc_msgoutq = 0;
	sc->sc_lastmsg = 0;

nextmsg:
	/* Pick up highest priority message. */
	sc->sc_currmsg = sc->sc_msgpriq & -sc->sc_msgpriq;
	sc->sc_msgpriq &= ~sc->sc_currmsg;
	sc->sc_msgoutq |= sc->sc_currmsg;

	/* Build the outgoing message data. */
	switch (sc->sc_currmsg) {
	case SEND_IDENTIFY:
		AIC_ASSERT(sc->sc_nexus != NULL);
		sc->sc_omess[0] =
		    MSG_IDENTIFY(sc->sc_nexus->xs->xs_periph->periph_lun, 1);
		n = 1;
		break;

#if AIC_USE_SYNCHRONOUS
	case SEND_SDTR:
		AIC_ASSERT(sc->sc_nexus != NULL);
		ti = &sc->sc_tinfo[sc->sc_nexus->xs->xs_periph->periph_target];
		sc->sc_omess[4] = MSG_EXTENDED;
		sc->sc_omess[3] = 3;
		sc->sc_omess[2] = MSG_EXT_SDTR;
		sc->sc_omess[1] = ti->period >> 2;
		sc->sc_omess[0] = ti->offset;
		n = 5;
		break;
#endif

#if AIC_USE_WIDE
	case SEND_WDTR:
		AIC_ASSERT(sc->sc_nexus != NULL);
		ti = &sc->sc_tinfo[sc->sc_nexus->xs->xs_periph->periph_target];
		sc->sc_omess[3] = MSG_EXTENDED;
		sc->sc_omess[2] = 2;
		sc->sc_omess[1] = MSG_EXT_WDTR;
		sc->sc_omess[0] = ti->width;
		n = 4;
		break;
#endif

	case SEND_DEV_RESET:
		sc->sc_flags |= AIC_ABORTING;
		sc->sc_omess[0] = MSG_BUS_DEV_RESET;
		n = 1;
		break;

	case SEND_REJECT:
		sc->sc_omess[0] = MSG_MESSAGE_REJECT;
		n = 1;
		break;

	case SEND_PARITY_ERROR:
		sc->sc_omess[0] = MSG_PARITY_ERROR;
		n = 1;
		break;

	case SEND_INIT_DET_ERR:
		sc->sc_omess[0] = MSG_INITIATOR_DET_ERR;
		n = 1;
		break;

	case SEND_ABORT:
		sc->sc_flags |= AIC_ABORTING;
		sc->sc_omess[0] = MSG_ABORT;
		n = 1;
		break;

	default:
		aprint_error_dev(sc->sc_dev,
		    "unexpected MESSAGE OUT; sending NOOP\n");
		AIC_BREAK();
		sc->sc_omess[0] = MSG_NOOP;
		n = 1;
		break;
	}
	sc->sc_omp = &sc->sc_omess[n];

nextbyte:
	/* Send message bytes. */
	for (;;) {
		for (;;) {
			sstat1 = bus_space_read_1(iot, ioh, SSTAT1);
			if ((sstat1 & (REQINIT | PHASECHG | BUSFREE)) != 0)
				break;
			/* Wait for REQINIT.  XXX Need timeout. */
		}
		if ((sstat1 & (PHASECHG | BUSFREE)) != 0) {
			/*
			 * Target left MESSAGE OUT, possibly to reject
			 * our message.
			 *
			 * If this is the last message being sent, then we
			 * deassert ATN, since either the target is going to
			 * ignore this message, or it's going to ask for a
			 * retransmission via MESSAGE PARITY ERROR (in which
			 * case we reassert ATN anyway).
			 */
			if (sc->sc_msgpriq == 0)
				bus_space_write_1(iot, ioh, CLRSINT1, CLRATNO);
			goto out;
		}

		/* Clear ATN before last byte if this is the last message. */
		if (n == 1 && sc->sc_msgpriq == 0)
			bus_space_write_1(iot, ioh, CLRSINT1, CLRATNO);
		/* Send message byte. */
		bus_space_write_1(iot, ioh, SCSIDAT, *--sc->sc_omp);
		--n;
		/* Keep track of the last message we've sent any bytes of. */
		sc->sc_lastmsg = sc->sc_currmsg;
		/* Wait for ACK to be negated.  XXX Need timeout. */
		while ((bus_space_read_1(iot, ioh, SCSISIG) & ACKI) != 0)
			;

		if (n == 0)
			break;
	}

	/* We get here only if the entire message has been transmitted. */
	if (sc->sc_msgpriq != 0) {
		/* There are more outgoing messages. */
		goto nextmsg;
	}

	/*
	 * The last message has been transmitted.  We need to remember the last
	 * message transmitted (in case the target switches to MESSAGE IN phase
	 * and sends a MESSAGE REJECT), and the list of messages transmitted
	 * this time around (in case the target stays in MESSAGE OUT phase to
	 * request a retransmit).
	 */

out:
	/* Disable REQ/ACK protocol. */
	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN);
}

/* aic_dataout_pio: perform a data transfer using the FIFO datapath in the
 * aic6360
 * Precondition: The SCSI bus should be in the DOUT phase, with REQ asserted
 * and ACK deasserted (i.e. waiting for a data byte)
 * This new revision has been optimized (I tried) to make the common case fast,
 * and the rarer cases (as a result) somewhat more complex
 */
static int
aic_dataout_pio(struct aic_softc *sc, u_char *p, int n)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
	u_char dmastat = 0;
	int out = 0;
#define DOUTAMOUNT 128		/* Full FIFO */

	AIC_MISC(("%02x%02x  ", bus_space_read_1(iot, ioh, FIFOSTAT),
	    bus_space_read_1(iot, ioh, SSTAT2)));

	/* Clear host FIFO and counter. */
	bus_space_write_1(iot, ioh, DMACNTRL0, RSTFIFO | WRITE);
	/* Enable FIFOs. */
	bus_space_write_1(iot, ioh, DMACNTRL0, ENDMA | DWORDPIO | WRITE);
	bus_space_write_1(iot, ioh, SXFRCTL0, SCSIEN | DMAEN | CHEN);

	/* Turn off ENREQINIT for now. */
	bus_space_write_1(iot, ioh, SIMODE1,
	    ENSCSIRST | ENSCSIPERR | ENBUSFREE | ENPHASECHG);

	/* I have tried to make the main loop as tight as possible.  This
	 * means that some of the code following the loop is a bit more
	 * complex than otherwise.
	 */
	while (n > 0) {
		for (;;) {
			dmastat = bus_space_read_1(iot, ioh, DMASTAT);
			if ((dmastat & (DFIFOEMP | INTSTAT)) != 0)
				break;
		}

		if ((dmastat & INTSTAT) != 0)
			goto phasechange;

		if (n >= DOUTAMOUNT) {
			n -= DOUTAMOUNT;
			out += DOUTAMOUNT;

#if AIC_USE_DWORDS
			bus_space_write_multi_4(iot, ioh, DMADATALONG,
			    (u_int32_t *) p, DOUTAMOUNT >> 2);
#else
			bus_space_write_multi_2(iot, ioh, DMADATA,
			    (u_int16_t *) p, DOUTAMOUNT >> 1);
#endif

			p += DOUTAMOUNT;
		} else {
			int xfer;

			xfer = n;
			AIC_MISC(("%d> ", xfer));

			n -= xfer;
			out += xfer;

#if AIC_USE_DWORDS
			if (xfer >= 12) {
				bus_space_write_multi_4(iot, ioh, DMADATALONG,
				    (u_int32_t *) p, xfer >> 2);
				p += xfer & ~3;
				xfer &= 3;
			}
#else
			if (xfer >= 8) {
				bus_space_write_multi_2(iot, ioh, DMADATA,
				    (u_int16_t *) p, xfer >> 1);
				p += xfer & ~1;
				xfer &= 1;
			}
#endif

			if (xfer > 0) {
				bus_space_write_1(iot, ioh, DMACNTRL0,
				    ENDMA | B8MODE | WRITE);
				bus_space_write_multi_1(iot, ioh, DMADATA,
				    p, xfer);
				p += xfer;
				bus_space_write_1(iot, ioh, DMACNTRL0,
				    ENDMA | DWORDPIO | WRITE);
			}
		}
	}

	if (out == 0) {
		bus_space_write_1(iot, ioh, SXFRCTL1, BITBUCKET);
		for (;;) {
			if ((bus_space_read_1(iot, ioh, DMASTAT) & INTSTAT)
			    != 0)
				break;
		}
		bus_space_write_1(iot, ioh, SXFRCTL1, 0);
		AIC_MISC(("extra data  "));
	} else {
		/* See the bytes off chip */
		for (;;) {
			dmastat = bus_space_read_1(iot, ioh, DMASTAT);
			if ((dmastat & INTSTAT) != 0)
				goto phasechange;
			if ((dmastat & DFIFOEMP) != 0 &&
			    (bus_space_read_1(iot, ioh, SSTAT2) & SEMPTY) != 0)
				break;
		}
	}

phasechange:
	if ((dmastat & INTSTAT) != 0) {
		/* Some sort of phase change. */
		int amount;

		/* Stop transfers, do some accounting */
		amount = bus_space_read_1(iot, ioh, FIFOSTAT)
		    + (bus_space_read_1(iot, ioh, SSTAT2) & 15);
		if (amount > 0) {
			out -= amount;
			bus_space_write_1(iot, ioh, DMACNTRL0,
			    RSTFIFO | WRITE);
			bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | CLRCH);
			AIC_MISC(("+%d ", amount));
		}
	}

	/* Turn on ENREQINIT again. */
	bus_space_write_1(iot, ioh, SIMODE1,
	    ENSCSIRST | ENSCSIPERR | ENBUSFREE | ENREQINIT | ENPHASECHG);

	/* Stop the FIFO data path. */
	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN);
	bus_space_write_1(iot, ioh, DMACNTRL0, 0);

	return out;
}

/* aic_datain_pio: perform data transfers using the FIFO datapath in the
 * aic6360
 * Precondition: The SCSI bus should be in the DIN phase, with REQ asserted
 * and ACK deasserted (i.e. at least one byte is ready).
 * For now, uses a pretty dumb algorithm, hangs around until all data has been
 * transferred.  This, is OK for fast targets, but not so smart for slow
 * targets which don't disconnect or for huge transfers.
 */
static int
aic_datain_pio(struct aic_softc *sc, u_char *p, int n)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
	u_char dmastat;
	int in = 0;
#define DINAMOUNT 128		/* Full FIFO */

	AIC_MISC(("%02x%02x  ", bus_space_read_1(iot, ioh, FIFOSTAT),
	    bus_space_read_1(iot, ioh, SSTAT2)));

	/* Clear host FIFO and counter. */
	bus_space_write_1(iot, ioh, DMACNTRL0, RSTFIFO);
	/* Enable FIFOs. */
	bus_space_write_1(iot, ioh, DMACNTRL0, ENDMA | DWORDPIO);
	bus_space_write_1(iot, ioh, SXFRCTL0, SCSIEN | DMAEN | CHEN);

	/* Turn off ENREQINIT for now. */
	bus_space_write_1(iot, ioh, SIMODE1,
	    ENSCSIRST | ENSCSIPERR | ENBUSFREE | ENPHASECHG);

	/* We leave this loop if one or more of the following is true:
	 * a) phase != PH_DATAIN && FIFOs are empty
	 * b) SCSIRSTI is set (a reset has occurred) or busfree is detected.
	 */
	while (n > 0) {
		/* Wait for fifo half full or phase mismatch */
		for (;;) {
			dmastat = bus_space_read_1(iot, ioh, DMASTAT);
			if ((dmastat & (DFIFOFULL | INTSTAT)) != 0)
				break;
		}

		if ((dmastat & DFIFOFULL) != 0) {
			n -= DINAMOUNT;
			in += DINAMOUNT;

#if AIC_USE_DWORDS
			bus_space_read_multi_4(iot, ioh, DMADATALONG,
			    (u_int32_t *) p, DINAMOUNT >> 2);
#else
			bus_space_read_multi_2(iot, ioh, DMADATA,
			    (u_int16_t *) p, DINAMOUNT >> 1);
#endif

			p += DINAMOUNT;
		} else {
			int xfer;

			xfer = uimin(bus_space_read_1(iot, ioh, FIFOSTAT), n);
			AIC_MISC((">%d ", xfer));

			n -= xfer;
			in += xfer;

#if AIC_USE_DWORDS
			if (xfer >= 12) {
				bus_space_read_multi_4(iot, ioh, DMADATALONG,
				    (u_int32_t *) p, xfer >> 2);
				p += xfer & ~3;
				xfer &= 3;
			}
#else
			if (xfer >= 8) {
				bus_space_read_multi_2(iot, ioh, DMADATA,
				    (u_int16_t *) p, xfer >> 1);
				p += xfer & ~1;
				xfer &= 1;
			}
#endif

			if (xfer > 0) {
				bus_space_write_1(iot, ioh, DMACNTRL0,
				    ENDMA | B8MODE);
				bus_space_read_multi_1(iot, ioh, DMADATA,
				    p, xfer);
				p += xfer;
				bus_space_write_1(iot, ioh, DMACNTRL0,
				    ENDMA | DWORDPIO);
			}
		}

		if ((dmastat & INTSTAT) != 0)
			goto phasechange;
	}

	/* Some SCSI-devices are rude enough to transfer more data than what
	 * was requested, e.g. 2048 bytes from a CD-ROM instead of the
	 * requested 512.  Test for progress, i.e. real transfers.  If no real
	 * transfers have been performed (n is probably already zero) and the
	 * FIFO is not empty, waste some bytes....
	 */
	if (in == 0) {
		bus_space_write_1(iot, ioh, SXFRCTL1, BITBUCKET);
		for (;;) {
			if ((bus_space_read_1(iot, ioh, DMASTAT) & INTSTAT)
			    != 0)
				break;
		}
		bus_space_write_1(iot, ioh, SXFRCTL1, 0);
		AIC_MISC(("extra data  "));
	}

phasechange:
	/* Turn on ENREQINIT again. */
	bus_space_write_1(iot, ioh, SIMODE1,
	    ENSCSIRST | ENSCSIPERR | ENBUSFREE | ENREQINIT | ENPHASECHG);

	/* Stop the FIFO data path. */
	bus_space_write_1(iot, ioh, SXFRCTL0, CHEN);
	bus_space_write_1(iot, ioh, DMACNTRL0, 0);

	return in;
}

/*
 * This is the workhorse routine of the driver.
 * Deficiencies (for now):
 * 1) always uses programmed I/O
 */
int
aicintr(void *arg)
{
	struct aic_softc *sc = arg;
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
	u_char sstat0, sstat1;
	struct aic_acb *acb;
	struct scsipi_periph *periph;
	struct aic_tinfo *ti;
	int n;

	if (!device_is_active(sc->sc_dev))
		return (0);

	/*
	 * Clear INTEN.  We enable it again before returning.  This makes the
	 * interrupt essentially level-triggered.
	 */
	bus_space_write_1(iot, ioh, DMACNTRL0, 0);

	AIC_TRACE(("aicintr  "));

loop:
	/*
	 * First check for abnormal conditions, such as reset.
	 */
	sstat1 = bus_space_read_1(iot, ioh, SSTAT1);
	AIC_MISC(("sstat1:0x%02x ", sstat1));

	if ((sstat1 & SCSIRSTI) != 0) {
		printf("%s: SCSI bus reset\n", device_xname(sc->sc_dev));
		goto reset;
	}

	/*
	 * Check for less serious errors.
	 */
	if ((sstat1 & SCSIPERR) != 0) {
		printf("%s: SCSI bus parity error\n", device_xname(sc->sc_dev));
		bus_space_write_1(iot, ioh, CLRSINT1, CLRSCSIPERR);
		if (sc->sc_prevphase == PH_MSGIN) {
			sc->sc_flags |= AIC_DROP_MSGIN;
			aic_sched_msgout(sc, SEND_PARITY_ERROR);
		} else
			aic_sched_msgout(sc, SEND_INIT_DET_ERR);
	}

	/*
	 * If we're not already busy doing something test for the following
	 * conditions:
	 * 1) We have been reselected by something
	 * 2) We have selected something successfully
	 * 3) Our selection process has timed out
	 * 4) This is really a bus free interrupt just to get a new command
	 *    going?
	 * 5) Spurious interrupt?
	 */
	switch (sc->sc_state) {
	case AIC_IDLE:
	case AIC_SELECTING:
		sstat0 = bus_space_read_1(iot, ioh, SSTAT0);
		AIC_MISC(("sstat0:0x%02x ", sstat0));

		if ((sstat0 & TARGET) != 0) {
			/*
			 * We don't currently support target mode.
			 */
			printf("%s: target mode selected; going to BUS FREE\n",
			    device_xname(sc->sc_dev));
			bus_space_write_1(iot, ioh, SCSISIG, 0);

			goto sched;
		} else if ((sstat0 & SELDI) != 0) {
			AIC_MISC(("reselected  "));

			/*
			 * If we're trying to select a target ourselves,
			 * push our command back into the ready list.
			 */
			if (sc->sc_state == AIC_SELECTING) {
				AIC_MISC(("backoff selector  "));
				AIC_ASSERT(sc->sc_nexus != NULL);
				acb = sc->sc_nexus;
				sc->sc_nexus = NULL;
				TAILQ_INSERT_HEAD(&sc->ready_list, acb, chain);
			}

			/* Save reselection ID. */
			sc->sc_selid = bus_space_read_1(iot, ioh, SELID);

			sc->sc_state = AIC_RESELECTED;
		} else if ((sstat0 & SELDO) != 0) {
			AIC_MISC(("selected  "));

			/* We have selected a target. Things to do:
			 * a) Determine what message(s) to send.
			 * b) Verify that we're still selecting the target.
			 * c) Mark device as busy.
			 */
			if (sc->sc_state != AIC_SELECTING) {
				printf("%s: selection out while idle; "
				    "resetting\n", device_xname(sc->sc_dev));
				AIC_BREAK();
				goto reset;
			}
			AIC_ASSERT(sc->sc_nexus != NULL);
			acb = sc->sc_nexus;
			periph = acb->xs->xs_periph;
			ti = &sc->sc_tinfo[periph->periph_target];

			sc->sc_msgpriq = SEND_IDENTIFY;
			if (acb->flags & ACB_RESET)
				sc->sc_msgpriq |= SEND_DEV_RESET;
			else if (acb->flags & ACB_ABORT)
				sc->sc_msgpriq |= SEND_ABORT;
			else {
#if AIC_USE_SYNCHRONOUS
				if ((ti->flags & DO_SYNC) != 0)
					sc->sc_msgpriq |= SEND_SDTR;
#endif
#if AIC_USE_WIDE
				if ((ti->flags & DO_WIDE) != 0)
					sc->sc_msgpriq |= SEND_WDTR;
#endif
			}

			acb->flags |= ACB_NEXUS;
			ti->lubusy |= (1 << periph->periph_lun);

			/* Do an implicit RESTORE POINTERS. */
			sc->sc_dp = acb->data_addr;
			sc->sc_dleft = acb->data_length;
			sc->sc_cp = (u_char *)&acb->scsipi_cmd;
			sc->sc_cleft = acb->scsipi_cmd_length;

			/* On our first connection, schedule a timeout. */
			if ((acb->xs->xs_control & XS_CTL_POLL) == 0)
				callout_reset(&acb->xs->xs_callout,
				    mstohz(acb->timeout), aic_timeout, acb);

			sc->sc_state = AIC_CONNECTED;
		} else if ((sstat1 & SELTO) != 0) {
			AIC_MISC(("selection timeout  "));

			if (sc->sc_state != AIC_SELECTING) {
				printf("%s: selection timeout while idle; "
				    "resetting\n", device_xname(sc->sc_dev));
				AIC_BREAK();
				goto reset;
			}
			AIC_ASSERT(sc->sc_nexus != NULL);
			acb = sc->sc_nexus;

			bus_space_write_1(iot, ioh, SXFRCTL1, 0);
			bus_space_write_1(iot, ioh, SCSISEQ, ENRESELI);
			bus_space_write_1(iot, ioh, CLRSINT1, CLRSELTIMO);
			delay(250);

			acb->xs->error = XS_SELTIMEOUT;
			goto finish;
		} else {
			if (sc->sc_state != AIC_IDLE) {
				printf("%s: BUS FREE while not idle; "
				    "state=%d\n",
				    device_xname(sc->sc_dev), sc->sc_state);
				AIC_BREAK();
				goto out;
			}

			goto sched;
		}

		/*
		 * Turn off selection stuff, and prepare to catch bus free
		 * interrupts, parity errors, and phase changes.
		 */
		bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | CLRSTCNT | CLRCH);
		bus_space_write_1(iot, ioh, SXFRCTL1, 0);
		bus_space_write_1(iot, ioh, SCSISEQ, ENAUTOATNP);
		bus_space_write_1(iot, ioh, CLRSINT0, CLRSELDI | CLRSELDO);
		bus_space_write_1(iot, ioh, CLRSINT1,
		    CLRBUSFREE | CLRPHASECHG);
		bus_space_write_1(iot, ioh, SIMODE0, 0);
		bus_space_write_1(iot, ioh, SIMODE1,
		    ENSCSIRST | ENSCSIPERR | ENBUSFREE | ENREQINIT |
		    ENPHASECHG);

		sc->sc_flags = 0;
		sc->sc_prevphase = PH_INVALID;
		goto dophase;
	}

	if ((sstat1 & BUSFREE) != 0) {
		/* We've gone to BUS FREE phase. */
		bus_space_write_1(iot, ioh, CLRSINT1,
		    CLRBUSFREE | CLRPHASECHG);

		switch (sc->sc_state) {
		case AIC_RESELECTED:
			goto sched;

		case AIC_CONNECTED:
			AIC_ASSERT(sc->sc_nexus != NULL);
			acb = sc->sc_nexus;

#if AIC_USE_SYNCHRONOUS + AIC_USE_WIDE
			if (sc->sc_prevphase == PH_MSGOUT) {
				/*
				 * If the target went to BUS FREE phase during
				 * or immediately after sending a SDTR or WDTR
				 * message, disable negotiation.
				 */
				periph = acb->xs->xs_periph;
				ti = &sc->sc_tinfo[periph->periph_target];
				switch (sc->sc_lastmsg) {
#if AIC_USE_SYNCHRONOUS
				case SEND_SDTR:
					ti->flags &= ~DO_SYNC;
					ti->period = ti->offset = 0;
					break;
#endif
#if AIC_USE_WIDE
				case SEND_WDTR:
					ti->flags &= ~DO_WIDE;
					ti->width = 0;
					break;
#endif
				}
			}
#endif

			if ((sc->sc_flags & AIC_ABORTING) == 0) {
				/*
				 * Section 5.1.1 of the SCSI 2 spec suggests
				 * issuing a REQUEST SENSE following an
				 * unexpected disconnect.  Some devices go into
				 * a contingent allegiance condition when
				 * disconnecting, and this is necessary to
				 * clean up their state.
				 */
				aprint_error_dev(sc->sc_dev,
				    "unexpected disconnect; "
				    "sending REQUEST SENSE\n");
				AIC_BREAK();
				aic_sense(sc, acb);
				goto out;
			}

			acb->xs->error = XS_DRIVER_STUFFUP;
			goto finish;

		case AIC_DISCONNECT:
			AIC_ASSERT(sc->sc_nexus != NULL);
			acb = sc->sc_nexus;
#if 1 /* XXXX */
			acb->data_addr = sc->sc_dp;
			acb->data_length = sc->sc_dleft;
#endif
			TAILQ_INSERT_HEAD(&sc->nexus_list, acb, chain);
			sc->sc_nexus = NULL;
			goto sched;

		case AIC_CMDCOMPLETE:
			AIC_ASSERT(sc->sc_nexus != NULL);
			acb = sc->sc_nexus;
			goto finish;
		}
	}

	bus_space_write_1(iot, ioh, CLRSINT1, CLRPHASECHG);

dophase:
	if ((sstat1 & REQINIT) == 0) {
		/* Wait for REQINIT. */
		goto out;
	}

	sc->sc_phase = bus_space_read_1(iot, ioh, SCSISIG) & PH_MASK;
	bus_space_write_1(iot, ioh, SCSISIG, sc->sc_phase);

	switch (sc->sc_phase) {
	case PH_MSGOUT:
		if (sc->sc_state != AIC_CONNECTED &&
		    sc->sc_state != AIC_RESELECTED)
			break;
		aic_msgout(sc);
		sc->sc_prevphase = PH_MSGOUT;
		goto loop;

	case PH_MSGIN:
		if (sc->sc_state != AIC_CONNECTED &&
		    sc->sc_state != AIC_RESELECTED)
			break;
		aic_msgin(sc);
		sc->sc_prevphase = PH_MSGIN;
		goto loop;

	case PH_CMD:
		if (sc->sc_state != AIC_CONNECTED)
			break;
#if AIC_DEBUG
		if ((aic_debug & AIC_SHOWMISC) != 0) {
			AIC_ASSERT(sc->sc_nexus != NULL);
			acb = sc->sc_nexus;
			printf("cmd=0x%02x+%d ",
			    acb->scsipi_cmd.opcode, acb->scsipi_cmd_length-1);
		}
#endif
		n = aic_dataout_pio(sc, sc->sc_cp, sc->sc_cleft);
		sc->sc_cp += n;
		sc->sc_cleft -= n;
		sc->sc_prevphase = PH_CMD;
		goto loop;

	case PH_DATAOUT:
		if (sc->sc_state != AIC_CONNECTED)
			break;
		AIC_MISC(("dataout %ld ", (long)sc->sc_dleft));
		n = aic_dataout_pio(sc, sc->sc_dp, sc->sc_dleft);
		sc->sc_dp += n;
		sc->sc_dleft -= n;
		sc->sc_prevphase = PH_DATAOUT;
		goto loop;

	case PH_DATAIN:
		if (sc->sc_state != AIC_CONNECTED)
			break;
		AIC_MISC(("datain %ld ", (long)sc->sc_dleft));
		n = aic_datain_pio(sc, sc->sc_dp, sc->sc_dleft);
		sc->sc_dp += n;
		sc->sc_dleft -= n;
		sc->sc_prevphase = PH_DATAIN;
		goto loop;

	case PH_STAT:
		if (sc->sc_state != AIC_CONNECTED)
			break;
		AIC_ASSERT(sc->sc_nexus != NULL);
		acb = sc->sc_nexus;
		bus_space_write_1(iot, ioh, SXFRCTL0, CHEN | SPIOEN);
		acb->target_stat = bus_space_read_1(iot, ioh, SCSIDAT);
		bus_space_write_1(iot, ioh, SXFRCTL0, CHEN);
		AIC_MISC(("target_stat=0x%02x  ", acb->target_stat));
		sc->sc_prevphase = PH_STAT;
		goto loop;
	}

	aprint_error_dev(sc->sc_dev, "unexpected bus phase; resetting\n");
	AIC_BREAK();
reset:
	aic_init(sc, 1);
	return 1;

finish:
	callout_stop(&acb->xs->xs_callout);
	aic_done(sc, acb);
	goto out;

sched:
	sc->sc_state = AIC_IDLE;
	aic_sched(sc);
	goto out;

out:
	bus_space_write_1(iot, ioh, DMACNTRL0, INTEN);
	return 1;
}

static void
aic_abort(struct aic_softc *sc, struct aic_acb *acb)
{

	/* 2 secs for the abort */
	acb->timeout = AIC_ABORT_TIMEOUT;
	acb->flags |= ACB_ABORT;

	if (acb == sc->sc_nexus) {
		/*
		 * If we're still selecting, the message will be scheduled
		 * after selection is complete.
		 */
		if (sc->sc_state == AIC_CONNECTED)
			aic_sched_msgout(sc, SEND_ABORT);
	} else {
		aic_dequeue(sc, acb);
		TAILQ_INSERT_HEAD(&sc->ready_list, acb, chain);
		if (sc->sc_state == AIC_IDLE)
			aic_sched(sc);
	}
}

static void
aic_timeout(void *arg)
{
	struct aic_acb *acb = arg;
	struct scsipi_xfer *xs = acb->xs;
	struct scsipi_periph *periph = xs->xs_periph;
	struct aic_softc *sc =
	    device_private(periph->periph_channel->chan_adapter->adapt_dev);
	int s;

	scsipi_printaddr(periph);
	printf("timed out");

	s = splbio();

	if (acb->flags & ACB_ABORT) {
		/* abort timed out */
		printf(" AGAIN\n");
		/* XXX Must reset! */
	} else {
		/* abort the operation that has timed out */
		printf("\n");
		acb->xs->error = XS_TIMEOUT;
		aic_abort(sc, acb);
	}

	splx(s);
}

#ifdef AIC_DEBUG
/*
 * The following functions are mostly used for debugging purposes, either
 * directly called from the driver or from the kernel debugger.
 */

static void
aic_show_scsi_cmd(struct aic_acb *acb)
{
	u_char  *b = (u_char *)&acb->scsipi_cmd;
	struct scsipi_periph *periph = acb->xs->xs_periph;
	int i;

	scsipi_printaddr(periph);
	if ((acb->xs->xs_control & XS_CTL_RESET) == 0) {
		for (i = 0; i < acb->scsipi_cmd_length; i++) {
			if (i)
				printf(",");
			printf("%x", b[i]);
		}
		printf("\n");
	} else
		printf("RESET\n");
}

static void
aic_print_acb(struct aic_acb *acb)
{

	printf("acb@%p xs=%p flags=%x", acb, acb->xs, acb->flags);
	printf(" dp=%p dleft=%d target_stat=%x\n",
	       acb->data_addr, acb->data_length, acb->target_stat);
	aic_show_scsi_cmd(acb);
}

void
aic_print_active_acb(void)
{
	struct aic_acb *acb;
	struct aic_softc *sc = device_lookup_private(&aic_cd, 0);

	printf("ready list:\n");
	for (acb = sc->ready_list.tqh_first; acb != NULL;
	    acb = acb->chain.tqe_next)
		aic_print_acb(acb);
	printf("nexus:\n");
	if (sc->sc_nexus != NULL)
		aic_print_acb(sc->sc_nexus);
	printf("nexus list:\n");
	for (acb = sc->nexus_list.tqh_first; acb != NULL;
	    acb = acb->chain.tqe_next)
		aic_print_acb(acb);
}

void
aic_dump6360(struct aic_softc *sc)
{
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;

	printf("aic6360: SCSISEQ=%x SXFRCTL0=%x SXFRCTL1=%x SCSISIG=%x\n",
	    bus_space_read_1(iot, ioh, SCSISEQ),
	    bus_space_read_1(iot, ioh, SXFRCTL0),
	    bus_space_read_1(iot, ioh, SXFRCTL1),
	    bus_space_read_1(iot, ioh, SCSISIG));
	printf("         SSTAT0=%x SSTAT1=%x SSTAT2=%x SSTAT3=%x SSTAT4=%x\n",
	    bus_space_read_1(iot, ioh, SSTAT0),
	    bus_space_read_1(iot, ioh, SSTAT1),
	    bus_space_read_1(iot, ioh, SSTAT2),
	    bus_space_read_1(iot, ioh, SSTAT3),
	    bus_space_read_1(iot, ioh, SSTAT4));
	printf("         SIMODE0=%x SIMODE1=%x DMACNTRL0=%x DMACNTRL1=%x "
	    "DMASTAT=%x\n",
	    bus_space_read_1(iot, ioh, SIMODE0),
	    bus_space_read_1(iot, ioh, SIMODE1),
	    bus_space_read_1(iot, ioh, DMACNTRL0),
	    bus_space_read_1(iot, ioh, DMACNTRL1),
	    bus_space_read_1(iot, ioh, DMASTAT));
	printf("         FIFOSTAT=%d SCSIBUS=0x%x\n",
	    bus_space_read_1(iot, ioh, FIFOSTAT),
	    bus_space_read_1(iot, ioh, SCSIBUS));
}

void
aic_dump_driver(struct aic_softc *sc)
{
	struct aic_tinfo *ti;
	int i;

	printf("nexus=%p prevphase=%x\n", sc->sc_nexus, sc->sc_prevphase);
	printf("state=%x msgin=%x msgpriq=%x msgoutq=%x lastmsg=%x "
	    "currmsg=%x\n",
	    sc->sc_state, sc->sc_imess[0],
	    sc->sc_msgpriq, sc->sc_msgoutq, sc->sc_lastmsg, sc->sc_currmsg);
	for (i = 0; i < 7; i++) {
		ti = &sc->sc_tinfo[i];
		printf("tinfo%d: %d cmds %d disconnects %d timeouts",
		    i, ti->cmds, ti->dconns, ti->touts);
		printf(" %d senses flags=%x\n", ti->senses, ti->flags);
	}
}
#endif