aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/scsi/mesh.c
blob: ff1933298da682c5f1b0704cbee9c4b81f6d083a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
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
/*
 * SCSI low-level driver for the MESH (Macintosh Enhanced SCSI Hardware)
 * bus adaptor found on Power Macintosh computers.
 * We assume the MESH is connected to a DBDMA (descriptor-based DMA)
 * controller.
 *
 * Paul Mackerras, August 1996.
 * Copyright (C) 1996 Paul Mackerras.
 *
 * Apr. 21 2002  - BenH		Rework bus reset code for new error handler
 *                              Add delay after initial bus reset
 *                              Add module parameters
 *
 * Sep. 27 2003  - BenH		Move to new driver model, fix some write posting
 *				issues
 * To do:
 * - handle aborts correctly
 * - retry arbitration if lost (unless higher levels do this for us)
 * - power down the chip when no device is detected
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/interrupt.h>
#include <linux/reboot.h>
#include <linux/spinlock.h>
#include <asm/dbdma.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/hydra.h>
#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/pci-bridge.h>
#include <asm/macio.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#include "mesh.h"

#if 1
#undef KERN_DEBUG
#define KERN_DEBUG KERN_WARNING
#endif

MODULE_AUTHOR("Paul Mackerras (paulus@samba.org)");
MODULE_DESCRIPTION("PowerMac MESH SCSI driver");
MODULE_LICENSE("GPL");

static int sync_rate = CONFIG_SCSI_MESH_SYNC_RATE;
static int sync_targets = 0xff;
static int resel_targets = 0xff;
static int debug_targets = 0;	/* print debug for these targets */
static int init_reset_delay = CONFIG_SCSI_MESH_RESET_DELAY_MS;

module_param(sync_rate, int, 0);
MODULE_PARM_DESC(sync_rate, "Synchronous rate (0..10, 0=async)");
module_param(sync_targets, int, 0);
MODULE_PARM_DESC(sync_targets, "Bitmask of targets allowed to set synchronous");
module_param(resel_targets, int, 0);
MODULE_PARM_DESC(resel_targets, "Bitmask of targets allowed to set disconnect");
module_param(debug_targets, int, 0644);
MODULE_PARM_DESC(debug_targets, "Bitmask of debugged targets");
module_param(init_reset_delay, int, 0);
MODULE_PARM_DESC(init_reset_delay, "Initial bus reset delay (0=no reset)");

static int mesh_sync_period = 100;
static int mesh_sync_offset = 0;
static unsigned char use_active_neg = 0;  /* bit mask for SEQ_ACTIVE_NEG if used */

#define ALLOW_SYNC(tgt)		((sync_targets >> (tgt)) & 1)
#define ALLOW_RESEL(tgt)	((resel_targets >> (tgt)) & 1)
#define ALLOW_DEBUG(tgt)	((debug_targets >> (tgt)) & 1)
#define DEBUG_TARGET(cmd)	((cmd) && ALLOW_DEBUG((cmd)->device->id))

#undef MESH_DBG
#define N_DBG_LOG	50
#define N_DBG_SLOG	20
#define NUM_DBG_EVENTS	13
#undef	DBG_USE_TB		/* bombs on 601 */

struct dbglog {
	char	*fmt;
	u32	tb;
	u8	phase;
	u8	bs0;
	u8	bs1;
	u8	tgt;
	int	d;
};

enum mesh_phase {
	idle,
	arbitrating,
	selecting,
	commanding,
	dataing,
	statusing,
	busfreeing,
	disconnecting,
	reselecting,
	sleeping
};

enum msg_phase {
	msg_none,
	msg_out,
	msg_out_xxx,
	msg_out_last,
	msg_in,
	msg_in_bad,
};

enum sdtr_phase {
	do_sdtr,
	sdtr_sent,
	sdtr_done
};

struct mesh_target {
	enum sdtr_phase sdtr_state;
	int	sync_params;
	int	data_goes_out;		/* guess as to data direction */
	struct scsi_cmnd *current_req;
	u32	saved_ptr;
#ifdef MESH_DBG
	int	log_ix;
	int	n_log;
	struct dbglog log[N_DBG_LOG];
#endif
};

struct mesh_state {
	volatile struct	mesh_regs __iomem *mesh;
	int	meshintr;
	volatile struct	dbdma_regs __iomem *dma;
	int	dmaintr;
	struct	Scsi_Host *host;
	struct	mesh_state *next;
	struct scsi_cmnd *request_q;
	struct scsi_cmnd *request_qtail;
	enum mesh_phase phase;		/* what we're currently trying to do */
	enum msg_phase msgphase;
	int	conn_tgt;		/* target we're connected to */
	struct scsi_cmnd *current_req;		/* req we're currently working on */
	int	data_ptr;
	int	dma_started;
	int	dma_count;
	int	stat;
	int	aborting;
	int	expect_reply;
	int	n_msgin;
	u8	msgin[16];
	int	n_msgout;
	int	last_n_msgout;
	u8	msgout[16];
	struct dbdma_cmd *dma_cmds;	/* space for dbdma commands, aligned */
	dma_addr_t dma_cmd_bus;
	void	*dma_cmd_space;
	int	dma_cmd_size;
	int	clk_freq;
	struct mesh_target tgts[8];
	struct macio_dev *mdev;
	struct pci_dev* pdev;
#ifdef MESH_DBG
	int	log_ix;
	int	n_log;
	struct dbglog log[N_DBG_SLOG];
#endif
};

/*
 * Driver is too messy, we need a few prototypes...
 */
static void mesh_done(struct mesh_state *ms, int start_next);
static void mesh_interrupt(int irq, void *dev_id, struct pt_regs *ptregs);
static void cmd_complete(struct mesh_state *ms);
static void set_dma_cmds(struct mesh_state *ms, struct scsi_cmnd *cmd);
static void halt_dma(struct mesh_state *ms);
static void phase_mismatch(struct mesh_state *ms);


/*
 * Some debugging & logging routines
 */

#ifdef MESH_DBG

static inline u32 readtb(void)
{
	u32 tb;

#ifdef DBG_USE_TB
	/* Beware: if you enable this, it will crash on 601s. */
	asm ("mftb %0" : "=r" (tb) : );
#else
	tb = 0;
#endif
	return tb;
}

static void dlog(struct mesh_state *ms, char *fmt, int a)
{
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
	struct dbglog *tlp, *slp;

	tlp = &tp->log[tp->log_ix];
	slp = &ms->log[ms->log_ix];
	tlp->fmt = fmt;
	tlp->tb = readtb();
	tlp->phase = (ms->msgphase << 4) + ms->phase;
	tlp->bs0 = ms->mesh->bus_status0;
	tlp->bs1 = ms->mesh->bus_status1;
	tlp->tgt = ms->conn_tgt;
	tlp->d = a;
	*slp = *tlp;
	if (++tp->log_ix >= N_DBG_LOG)
		tp->log_ix = 0;
	if (tp->n_log < N_DBG_LOG)
		++tp->n_log;
	if (++ms->log_ix >= N_DBG_SLOG)
		ms->log_ix = 0;
	if (ms->n_log < N_DBG_SLOG)
		++ms->n_log;
}

static void dumplog(struct mesh_state *ms, int t)
{
	struct mesh_target *tp = &ms->tgts[t];
	struct dbglog *lp;
	int i;

	if (tp->n_log == 0)
		return;
	i = tp->log_ix - tp->n_log;
	if (i < 0)
		i += N_DBG_LOG;
	tp->n_log = 0;
	do {
		lp = &tp->log[i];
		printk(KERN_DEBUG "mesh log %d: bs=%.2x%.2x ph=%.2x ",
		       t, lp->bs1, lp->bs0, lp->phase);
#ifdef DBG_USE_TB
		printk("tb=%10u ", lp->tb);
#endif
		printk(lp->fmt, lp->d);
		printk("\n");
		if (++i >= N_DBG_LOG)
			i = 0;
	} while (i != tp->log_ix);
}

static void dumpslog(struct mesh_state *ms)
{
	struct dbglog *lp;
	int i;

	if (ms->n_log == 0)
		return;
	i = ms->log_ix - ms->n_log;
	if (i < 0)
		i += N_DBG_SLOG;
	ms->n_log = 0;
	do {
		lp = &ms->log[i];
		printk(KERN_DEBUG "mesh log: bs=%.2x%.2x ph=%.2x t%d ",
		       lp->bs1, lp->bs0, lp->phase, lp->tgt);
#ifdef DBG_USE_TB
		printk("tb=%10u ", lp->tb);
#endif
		printk(lp->fmt, lp->d);
		printk("\n");
		if (++i >= N_DBG_SLOG)
			i = 0;
	} while (i != ms->log_ix);
}

#else

static inline void dlog(struct mesh_state *ms, char *fmt, int a)
{}
static inline void dumplog(struct mesh_state *ms, int tgt)
{}
static inline void dumpslog(struct mesh_state *ms)
{}

#endif /* MESH_DBG */

#define MKWORD(a, b, c, d)	(((a) << 24) + ((b) << 16) + ((c) << 8) + (d))

static void
mesh_dump_regs(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	volatile struct dbdma_regs __iomem *md = ms->dma;
	int t;
	struct mesh_target *tp;

	printk(KERN_DEBUG "mesh: state at %p, regs at %p, dma at %p\n",
	       ms, mr, md);
	printk(KERN_DEBUG "    ct=%4x seq=%2x bs=%4x fc=%2x "
	       "exc=%2x err=%2x im=%2x int=%2x sp=%2x\n",
	       (mr->count_hi << 8) + mr->count_lo, mr->sequence,
	       (mr->bus_status1 << 8) + mr->bus_status0, mr->fifo_count,
	       mr->exception, mr->error, mr->intr_mask, mr->interrupt,
	       mr->sync_params);
	while(in_8(&mr->fifo_count))
		printk(KERN_DEBUG " fifo data=%.2x\n",in_8(&mr->fifo));
	printk(KERN_DEBUG "    dma stat=%x cmdptr=%x\n",
	       in_le32(&md->status), in_le32(&md->cmdptr));
	printk(KERN_DEBUG "    phase=%d msgphase=%d conn_tgt=%d data_ptr=%d\n",
	       ms->phase, ms->msgphase, ms->conn_tgt, ms->data_ptr);
	printk(KERN_DEBUG "    dma_st=%d dma_ct=%d n_msgout=%d\n",
	       ms->dma_started, ms->dma_count, ms->n_msgout);
	for (t = 0; t < 8; ++t) {
		tp = &ms->tgts[t];
		if (tp->current_req == NULL)
			continue;
		printk(KERN_DEBUG "    target %d: req=%p goes_out=%d saved_ptr=%d\n",
		       t, tp->current_req, tp->data_goes_out, tp->saved_ptr);
	}
}


/*
 * Flush write buffers on the bus path to the mesh
 */
static inline void mesh_flush_io(volatile struct mesh_regs __iomem *mr)
{
	(void)in_8(&mr->mesh_id);
}


/*
 * Complete a SCSI command
 */
static void mesh_completed(struct mesh_state *ms, struct scsi_cmnd *cmd)
{
	(*cmd->scsi_done)(cmd);
}


/* Called with  meshinterrupt disabled, initialize the chipset
 * and eventually do the initial bus reset. The lock must not be
 * held since we can schedule.
 */
static void mesh_init(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	volatile struct dbdma_regs __iomem *md = ms->dma;

	mesh_flush_io(mr);
	udelay(100);

	/* Reset controller */
	out_le32(&md->control, (RUN|PAUSE|FLUSH|WAKE) << 16);	/* stop dma */
	out_8(&mr->exception, 0xff);	/* clear all exception bits */
	out_8(&mr->error, 0xff);	/* clear all error bits */
	out_8(&mr->sequence, SEQ_RESETMESH);
	mesh_flush_io(mr);
	udelay(10);
	out_8(&mr->intr_mask, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
	out_8(&mr->source_id, ms->host->this_id);
	out_8(&mr->sel_timeout, 25);	/* 250ms */
	out_8(&mr->sync_params, ASYNC_PARAMS);

	if (init_reset_delay) {
		printk(KERN_INFO "mesh: performing initial bus reset...\n");
		
		/* Reset bus */
		out_8(&mr->bus_status1, BS1_RST);	/* assert RST */
		mesh_flush_io(mr);
		udelay(30);			/* leave it on for >= 25us */
		out_8(&mr->bus_status1, 0);	/* negate RST */
		mesh_flush_io(mr);

		/* Wait for bus to come back */
		msleep(init_reset_delay);
	}
	
	/* Reconfigure controller */
	out_8(&mr->interrupt, 0xff);	/* clear all interrupt bits */
	out_8(&mr->sequence, SEQ_FLUSHFIFO);
	mesh_flush_io(mr);
	udelay(1);
	out_8(&mr->sync_params, ASYNC_PARAMS);
	out_8(&mr->sequence, SEQ_ENBRESEL);

	ms->phase = idle;
	ms->msgphase = msg_none;
}


static void mesh_start_cmd(struct mesh_state *ms, struct scsi_cmnd *cmd)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	int t, id;

	id = cmd->device->id;
	ms->current_req = cmd;
	ms->tgts[id].data_goes_out = cmd->sc_data_direction == DMA_TO_DEVICE;
	ms->tgts[id].current_req = cmd;

#if 1
	if (DEBUG_TARGET(cmd)) {
		int i;
		printk(KERN_DEBUG "mesh_start: %p ser=%lu tgt=%d cmd=",
		       cmd, cmd->serial_number, id);
		for (i = 0; i < cmd->cmd_len; ++i)
			printk(" %x", cmd->cmnd[i]);
		printk(" use_sg=%d buffer=%p bufflen=%u\n",
		       cmd->use_sg, cmd->request_buffer, cmd->request_bufflen);
	}
#endif
	if (ms->dma_started)
		panic("mesh: double DMA start !\n");

	ms->phase = arbitrating;
	ms->msgphase = msg_none;
	ms->data_ptr = 0;
	ms->dma_started = 0;
	ms->n_msgout = 0;
	ms->last_n_msgout = 0;
	ms->expect_reply = 0;
	ms->conn_tgt = id;
	ms->tgts[id].saved_ptr = 0;
	ms->stat = DID_OK;
	ms->aborting = 0;
#ifdef MESH_DBG
	ms->tgts[id].n_log = 0;
	dlog(ms, "start cmd=%x", (int) cmd);
#endif

	/* Off we go */
	dlog(ms, "about to arb, intr/exc/err/fc=%.8x",
	     MKWORD(mr->interrupt, mr->exception, mr->error, mr->fifo_count));
	out_8(&mr->interrupt, INT_CMDDONE);
	out_8(&mr->sequence, SEQ_ENBRESEL);
	mesh_flush_io(mr);
	udelay(1);

	if (in_8(&mr->bus_status1) & (BS1_BSY | BS1_SEL)) {
		/*
		 * Some other device has the bus or is arbitrating for it -
		 * probably a target which is about to reselect us.
		 */
		dlog(ms, "busy b4 arb, intr/exc/err/fc=%.8x",
		     MKWORD(mr->interrupt, mr->exception,
			    mr->error, mr->fifo_count));
		for (t = 100; t > 0; --t) {
			if ((in_8(&mr->bus_status1) & (BS1_BSY | BS1_SEL)) == 0)
				break;
			if (in_8(&mr->interrupt) != 0) {
				dlog(ms, "intr b4 arb, intr/exc/err/fc=%.8x",
				     MKWORD(mr->interrupt, mr->exception,
					    mr->error, mr->fifo_count));
				mesh_interrupt(0, (void *)ms, NULL);
				if (ms->phase != arbitrating)
					return;
			}
			udelay(1);
		}
		if (in_8(&mr->bus_status1) & (BS1_BSY | BS1_SEL)) {
			/* XXX should try again in a little while */
			ms->stat = DID_BUS_BUSY;
			ms->phase = idle;
			mesh_done(ms, 0);
			return;
		}
	}

	/*
	 * Apparently the mesh has a bug where it will assert both its
	 * own bit and the target's bit on the bus during arbitration.
	 */
	out_8(&mr->dest_id, mr->source_id);

	/*
	 * There appears to be a race with reselection sometimes,
	 * where a target reselects us just as we issue the
	 * arbitrate command.  It seems that then the arbitrate
	 * command just hangs waiting for the bus to be free
	 * without giving us a reselection exception.
	 * The only way I have found to get it to respond correctly
	 * is this: disable reselection before issuing the arbitrate
	 * command, then after issuing it, if it looks like a target
	 * is trying to reselect us, reset the mesh and then enable
	 * reselection.
	 */
	out_8(&mr->sequence, SEQ_DISRESEL);
	if (in_8(&mr->interrupt) != 0) {
		dlog(ms, "intr after disresel, intr/exc/err/fc=%.8x",
		     MKWORD(mr->interrupt, mr->exception,
			    mr->error, mr->fifo_count));
		mesh_interrupt(0, (void *)ms, NULL);
		if (ms->phase != arbitrating)
			return;
		dlog(ms, "after intr after disresel, intr/exc/err/fc=%.8x",
		     MKWORD(mr->interrupt, mr->exception,
			    mr->error, mr->fifo_count));
	}

	out_8(&mr->sequence, SEQ_ARBITRATE);

	for (t = 230; t > 0; --t) {
		if (in_8(&mr->interrupt) != 0)
			break;
		udelay(1);
	}
	dlog(ms, "after arb, intr/exc/err/fc=%.8x",
	     MKWORD(mr->interrupt, mr->exception, mr->error, mr->fifo_count));
	if (in_8(&mr->interrupt) == 0 && (in_8(&mr->bus_status1) & BS1_SEL)
	    && (in_8(&mr->bus_status0) & BS0_IO)) {
		/* looks like a reselection - try resetting the mesh */
		dlog(ms, "resel? after arb, intr/exc/err/fc=%.8x",
		     MKWORD(mr->interrupt, mr->exception, mr->error, mr->fifo_count));
		out_8(&mr->sequence, SEQ_RESETMESH);
		mesh_flush_io(mr);
		udelay(10);
		out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
		out_8(&mr->intr_mask, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
		out_8(&mr->sequence, SEQ_ENBRESEL);
		mesh_flush_io(mr);
		for (t = 10; t > 0 && in_8(&mr->interrupt) == 0; --t)
			udelay(1);
		dlog(ms, "tried reset after arb, intr/exc/err/fc=%.8x",
		     MKWORD(mr->interrupt, mr->exception, mr->error, mr->fifo_count));
#ifndef MESH_MULTIPLE_HOSTS
		if (in_8(&mr->interrupt) == 0 && (in_8(&mr->bus_status1) & BS1_SEL)
		    && (in_8(&mr->bus_status0) & BS0_IO)) {
			printk(KERN_ERR "mesh: controller not responding"
			       " to reselection!\n");
			/*
			 * If this is a target reselecting us, and the
			 * mesh isn't responding, the higher levels of
			 * the scsi code will eventually time out and
			 * reset the bus.
			 */
		}
#endif
	}
}

/*
 * Start the next command for a MESH.
 * Should be called with interrupts disabled.
 */
static void mesh_start(struct mesh_state *ms)
{
	struct scsi_cmnd *cmd, *prev, *next;

	if (ms->phase != idle || ms->current_req != NULL) {
		printk(KERN_ERR "inappropriate mesh_start (phase=%d, ms=%p)",
		       ms->phase, ms);
		return;
	}

	while (ms->phase == idle) {
		prev = NULL;
		for (cmd = ms->request_q; ; cmd = (struct scsi_cmnd *) cmd->host_scribble) {
			if (cmd == NULL)
				return;
			if (ms->tgts[cmd->device->id].current_req == NULL)
				break;
			prev = cmd;
		}
		next = (struct scsi_cmnd *) cmd->host_scribble;
		if (prev == NULL)
			ms->request_q = next;
		else
			prev->host_scribble = (void *) next;
		if (next == NULL)
			ms->request_qtail = prev;

		mesh_start_cmd(ms, cmd);
	}
}

static void mesh_done(struct mesh_state *ms, int start_next)
{
	struct scsi_cmnd *cmd;
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];

	cmd = ms->current_req;
	ms->current_req = NULL;
	tp->current_req = NULL;
	if (cmd) {
		cmd->result = (ms->stat << 16) + cmd->SCp.Status;
		if (ms->stat == DID_OK)
			cmd->result += (cmd->SCp.Message << 8);
		if (DEBUG_TARGET(cmd)) {
			printk(KERN_DEBUG "mesh_done: result = %x, data_ptr=%d, buflen=%d\n",
			       cmd->result, ms->data_ptr, cmd->request_bufflen);
			if ((cmd->cmnd[0] == 0 || cmd->cmnd[0] == 0x12 || cmd->cmnd[0] == 3)
			    && cmd->request_buffer != 0) {
				unsigned char *b = cmd->request_buffer;
				printk(KERN_DEBUG "buffer = %x %x %x %x %x %x %x %x\n",
				       b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7]);
			}
		}
		cmd->SCp.this_residual -= ms->data_ptr;
		mesh_completed(ms, cmd);
	}
	if (start_next) {
		out_8(&ms->mesh->sequence, SEQ_ENBRESEL);
		mesh_flush_io(ms->mesh);
		udelay(1);
		ms->phase = idle;
		mesh_start(ms);
	}
}

static inline void add_sdtr_msg(struct mesh_state *ms)
{
	int i = ms->n_msgout;

	ms->msgout[i] = EXTENDED_MESSAGE;
	ms->msgout[i+1] = 3;
	ms->msgout[i+2] = EXTENDED_SDTR;
	ms->msgout[i+3] = mesh_sync_period/4;
	ms->msgout[i+4] = (ALLOW_SYNC(ms->conn_tgt)? mesh_sync_offset: 0);
	ms->n_msgout = i + 5;
}

static void set_sdtr(struct mesh_state *ms, int period, int offset)
{
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	int v, tr;

	tp->sdtr_state = sdtr_done;
	if (offset == 0) {
		/* asynchronous */
		if (SYNC_OFF(tp->sync_params))
			printk(KERN_INFO "mesh: target %d now asynchronous\n",
			       ms->conn_tgt);
		tp->sync_params = ASYNC_PARAMS;
		out_8(&mr->sync_params, ASYNC_PARAMS);
		return;
	}
	/*
	 * We need to compute ceil(clk_freq * period / 500e6) - 2
	 * without incurring overflow.
	 */
	v = (ms->clk_freq / 5000) * period;
	if (v <= 250000) {
		/* special case: sync_period == 5 * clk_period */
		v = 0;
		/* units of tr are 100kB/s */
		tr = (ms->clk_freq + 250000) / 500000;
	} else {
		/* sync_period == (v + 2) * 2 * clk_period */
		v = (v + 99999) / 100000 - 2;
		if (v > 15)
			v = 15;	/* oops */
		tr = ((ms->clk_freq / (v + 2)) + 199999) / 200000;
	}
	if (offset > 15)
		offset = 15;	/* can't happen */
	tp->sync_params = SYNC_PARAMS(offset, v);
	out_8(&mr->sync_params, tp->sync_params);
	printk(KERN_INFO "mesh: target %d synchronous at %d.%d MB/s\n",
	       ms->conn_tgt, tr/10, tr%10);
}

static void start_phase(struct mesh_state *ms)
{
	int i, seq, nb;
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	volatile struct dbdma_regs __iomem *md = ms->dma;
	struct scsi_cmnd *cmd = ms->current_req;
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];

	dlog(ms, "start_phase nmo/exc/fc/seq = %.8x",
	     MKWORD(ms->n_msgout, mr->exception, mr->fifo_count, mr->sequence));
	out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
	seq = use_active_neg + (ms->n_msgout? SEQ_ATN: 0);
	switch (ms->msgphase) {
	case msg_none:
		break;

	case msg_in:
		out_8(&mr->count_hi, 0);
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGIN + seq);
		ms->n_msgin = 0;
		return;

	case msg_out:
		/*
		 * To make sure ATN drops before we assert ACK for
		 * the last byte of the message, we have to do the
		 * last byte specially.
		 */
		if (ms->n_msgout <= 0) {
			printk(KERN_ERR "mesh: msg_out but n_msgout=%d\n",
			       ms->n_msgout);
			mesh_dump_regs(ms);
			ms->msgphase = msg_none;
			break;
		}
		if (ALLOW_DEBUG(ms->conn_tgt)) {
			printk(KERN_DEBUG "mesh: sending %d msg bytes:",
			       ms->n_msgout);
			for (i = 0; i < ms->n_msgout; ++i)
				printk(" %x", ms->msgout[i]);
			printk("\n");
		}
		dlog(ms, "msgout msg=%.8x", MKWORD(ms->n_msgout, ms->msgout[0],
						ms->msgout[1], ms->msgout[2]));
		out_8(&mr->count_hi, 0);
		out_8(&mr->sequence, SEQ_FLUSHFIFO);
		mesh_flush_io(mr);
		udelay(1);
		/*
		 * If ATN is not already asserted, we assert it, then
		 * issue a SEQ_MSGOUT to get the mesh to drop ACK.
		 */
		if ((in_8(&mr->bus_status0) & BS0_ATN) == 0) {
			dlog(ms, "bus0 was %.2x explictly asserting ATN", mr->bus_status0);
			out_8(&mr->bus_status0, BS0_ATN); /* explicit ATN */
			mesh_flush_io(mr);
			udelay(1);
			out_8(&mr->count_lo, 1);
			out_8(&mr->sequence, SEQ_MSGOUT + seq);
			out_8(&mr->bus_status0, 0); /* release explicit ATN */
			dlog(ms,"hace: after explicit ATN bus0=%.2x",mr->bus_status0);
		}
		if (ms->n_msgout == 1) {
			/*
			 * We can't issue the SEQ_MSGOUT without ATN
			 * until the target has asserted REQ.  The logic
			 * in cmd_complete handles both situations:
			 * REQ already asserted or not.
			 */
			cmd_complete(ms);
		} else {
			out_8(&mr->count_lo, ms->n_msgout - 1);
			out_8(&mr->sequence, SEQ_MSGOUT + seq);
			for (i = 0; i < ms->n_msgout - 1; ++i)
				out_8(&mr->fifo, ms->msgout[i]);
		}
		return;

	default:
		printk(KERN_ERR "mesh bug: start_phase msgphase=%d\n",
		       ms->msgphase);
	}

	switch (ms->phase) {
	case selecting:
		out_8(&mr->dest_id, ms->conn_tgt);
		out_8(&mr->sequence, SEQ_SELECT + SEQ_ATN);
		break;
	case commanding:
		out_8(&mr->sync_params, tp->sync_params);
		out_8(&mr->count_hi, 0);
		if (cmd) {
			out_8(&mr->count_lo, cmd->cmd_len);
			out_8(&mr->sequence, SEQ_COMMAND + seq);
			for (i = 0; i < cmd->cmd_len; ++i)
				out_8(&mr->fifo, cmd->cmnd[i]);
		} else {
			out_8(&mr->count_lo, 6);
			out_8(&mr->sequence, SEQ_COMMAND + seq);
			for (i = 0; i < 6; ++i)
				out_8(&mr->fifo, 0);
		}
		break;
	case dataing:
		/* transfer data, if any */
		if (!ms->dma_started) {
			set_dma_cmds(ms, cmd);
			out_le32(&md->cmdptr, virt_to_phys(ms->dma_cmds));
			out_le32(&md->control, (RUN << 16) | RUN);
			ms->dma_started = 1;
		}
		nb = ms->dma_count;
		if (nb > 0xfff0)
			nb = 0xfff0;
		ms->dma_count -= nb;
		ms->data_ptr += nb;
		out_8(&mr->count_lo, nb);
		out_8(&mr->count_hi, nb >> 8);
		out_8(&mr->sequence, (tp->data_goes_out?
				SEQ_DATAOUT: SEQ_DATAIN) + SEQ_DMA_MODE + seq);
		break;
	case statusing:
		out_8(&mr->count_hi, 0);
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_STATUS + seq);
		break;
	case busfreeing:
	case disconnecting:
		out_8(&mr->sequence, SEQ_ENBRESEL);
		mesh_flush_io(mr);
		udelay(1);
		dlog(ms, "enbresel intr/exc/err/fc=%.8x",
		     MKWORD(mr->interrupt, mr->exception, mr->error,
			    mr->fifo_count));
		out_8(&mr->sequence, SEQ_BUSFREE);
		break;
	default:
		printk(KERN_ERR "mesh: start_phase called with phase=%d\n",
		       ms->phase);
		dumpslog(ms);
	}

}

static inline void get_msgin(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	int i, n;

	n = mr->fifo_count;
	if (n != 0) {
		i = ms->n_msgin;
		ms->n_msgin = i + n;
		for (; n > 0; --n)
			ms->msgin[i++] = in_8(&mr->fifo);
	}
}

static inline int msgin_length(struct mesh_state *ms)
{
	int b, n;

	n = 1;
	if (ms->n_msgin > 0) {
		b = ms->msgin[0];
		if (b == 1) {
			/* extended message */
			n = ms->n_msgin < 2? 2: ms->msgin[1] + 2;
		} else if (0x20 <= b && b <= 0x2f) {
			/* 2-byte message */
			n = 2;
		}
	}
	return n;
}

static void reselected(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	struct scsi_cmnd *cmd;
	struct mesh_target *tp;
	int b, t, prev;

	switch (ms->phase) {
	case idle:
		break;
	case arbitrating:
		if ((cmd = ms->current_req) != NULL) {
			/* put the command back on the queue */
			cmd->host_scribble = (void *) ms->request_q;
			if (ms->request_q == NULL)
				ms->request_qtail = cmd;
			ms->request_q = cmd;
			tp = &ms->tgts[cmd->device->id];
			tp->current_req = NULL;
		}
		break;
	case busfreeing:
		ms->phase = reselecting;
		mesh_done(ms, 0);
		break;
	case disconnecting:
		break;
	default:
		printk(KERN_ERR "mesh: reselected in phase %d/%d tgt %d\n",
		       ms->msgphase, ms->phase, ms->conn_tgt);
		dumplog(ms, ms->conn_tgt);
		dumpslog(ms);
	}

	if (ms->dma_started) {
		printk(KERN_ERR "mesh: reselected with DMA started !\n");
		halt_dma(ms);
	}
	ms->current_req = NULL;
	ms->phase = dataing;
	ms->msgphase = msg_in;
	ms->n_msgout = 0;
	ms->last_n_msgout = 0;
	prev = ms->conn_tgt;

	/*
	 * We seem to get abortive reselections sometimes.
	 */
	while ((in_8(&mr->bus_status1) & BS1_BSY) == 0) {
		static int mesh_aborted_resels;
		mesh_aborted_resels++;
		out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
		mesh_flush_io(mr);
		udelay(1);
		out_8(&mr->sequence, SEQ_ENBRESEL);
		mesh_flush_io(mr);
		udelay(5);
		dlog(ms, "extra resel err/exc/fc = %.6x",
		     MKWORD(0, mr->error, mr->exception, mr->fifo_count));
	}
	out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
       	mesh_flush_io(mr);
	udelay(1);
	out_8(&mr->sequence, SEQ_ENBRESEL);
       	mesh_flush_io(mr);
	udelay(1);
	out_8(&mr->sync_params, ASYNC_PARAMS);

	/*
	 * Find out who reselected us.
	 */
	if (in_8(&mr->fifo_count) == 0) {
		printk(KERN_ERR "mesh: reselection but nothing in fifo?\n");
		ms->conn_tgt = ms->host->this_id;
		goto bogus;
	}
	/* get the last byte in the fifo */
	do {
		b = in_8(&mr->fifo);
		dlog(ms, "reseldata %x", b);
	} while (in_8(&mr->fifo_count));
	for (t = 0; t < 8; ++t)
		if ((b & (1 << t)) != 0 && t != ms->host->this_id)
			break;
	if (b != (1 << t) + (1 << ms->host->this_id)) {
		printk(KERN_ERR "mesh: bad reselection data %x\n", b);
		ms->conn_tgt = ms->host->this_id;
		goto bogus;
	}


	/*
	 * Set up to continue with that target's transfer.
	 */
	ms->conn_tgt = t;
	tp = &ms->tgts[t];
	out_8(&mr->sync_params, tp->sync_params);
	if (ALLOW_DEBUG(t)) {
		printk(KERN_DEBUG "mesh: reselected by target %d\n", t);
		printk(KERN_DEBUG "mesh: saved_ptr=%x goes_out=%d cmd=%p\n",
		       tp->saved_ptr, tp->data_goes_out, tp->current_req);
	}
	ms->current_req = tp->current_req;
	if (tp->current_req == NULL) {
		printk(KERN_ERR "mesh: reselected by tgt %d but no cmd!\n", t);
		goto bogus;
	}
	ms->data_ptr = tp->saved_ptr;
	dlog(ms, "resel prev tgt=%d", prev);
	dlog(ms, "resel err/exc=%.4x", MKWORD(0, 0, mr->error, mr->exception));
	start_phase(ms);
	return;

bogus:
	dumplog(ms, ms->conn_tgt);
	dumpslog(ms);
	ms->data_ptr = 0;
	ms->aborting = 1;
	start_phase(ms);
}

static void do_abort(struct mesh_state *ms)
{
	ms->msgout[0] = ABORT;
	ms->n_msgout = 1;
	ms->aborting = 1;
	ms->stat = DID_ABORT;
	dlog(ms, "abort", 0);
}

static void handle_reset(struct mesh_state *ms)
{
	int tgt;
	struct mesh_target *tp;
	struct scsi_cmnd *cmd;
	volatile struct mesh_regs __iomem *mr = ms->mesh;

	for (tgt = 0; tgt < 8; ++tgt) {
		tp = &ms->tgts[tgt];
		if ((cmd = tp->current_req) != NULL) {
			cmd->result = DID_RESET << 16;
			tp->current_req = NULL;
			mesh_completed(ms, cmd);
		}
		ms->tgts[tgt].sdtr_state = do_sdtr;
		ms->tgts[tgt].sync_params = ASYNC_PARAMS;
	}
	ms->current_req = NULL;
	while ((cmd = ms->request_q) != NULL) {
		ms->request_q = (struct scsi_cmnd *) cmd->host_scribble;
		cmd->result = DID_RESET << 16;
		mesh_completed(ms, cmd);
	}
	ms->phase = idle;
	ms->msgphase = msg_none;
	out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
	out_8(&mr->sequence, SEQ_FLUSHFIFO);
       	mesh_flush_io(mr);
	udelay(1);
	out_8(&mr->sync_params, ASYNC_PARAMS);
	out_8(&mr->sequence, SEQ_ENBRESEL);
}

static irqreturn_t do_mesh_interrupt(int irq, void *dev_id, struct pt_regs *ptregs)
{
	unsigned long flags;
	struct Scsi_Host *dev = ((struct mesh_state *)dev_id)->host;
	
	spin_lock_irqsave(dev->host_lock, flags);
	mesh_interrupt(irq, dev_id, ptregs);
	spin_unlock_irqrestore(dev->host_lock, flags);
	return IRQ_HANDLED;
}

static void handle_error(struct mesh_state *ms)
{
	int err, exc, count;
	volatile struct mesh_regs __iomem *mr = ms->mesh;

	err = in_8(&mr->error);
	exc = in_8(&mr->exception);
	out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
	dlog(ms, "error err/exc/fc/cl=%.8x",
	     MKWORD(err, exc, mr->fifo_count, mr->count_lo));
	if (err & ERR_SCSIRESET) {
		/* SCSI bus was reset */
		printk(KERN_INFO "mesh: SCSI bus reset detected: "
		       "waiting for end...");
		while ((in_8(&mr->bus_status1) & BS1_RST) != 0)
			udelay(1);
		printk("done\n");
		handle_reset(ms);
		/* request_q is empty, no point in mesh_start() */
		return;
	}
	if (err & ERR_UNEXPDISC) {
		/* Unexpected disconnect */
		if (exc & EXC_RESELECTED) {
			reselected(ms);
			return;
		}
		if (!ms->aborting) {
			printk(KERN_WARNING "mesh: target %d aborted\n",
			       ms->conn_tgt);
			dumplog(ms, ms->conn_tgt);
			dumpslog(ms);
		}
		out_8(&mr->interrupt, INT_CMDDONE);
		ms->stat = DID_ABORT;
		mesh_done(ms, 1);
		return;
	}
	if (err & ERR_PARITY) {
		if (ms->msgphase == msg_in) {
			printk(KERN_ERR "mesh: msg parity error, target %d\n",
			       ms->conn_tgt);
			ms->msgout[0] = MSG_PARITY_ERROR;
			ms->n_msgout = 1;
			ms->msgphase = msg_in_bad;
			cmd_complete(ms);
			return;
		}
		if (ms->stat == DID_OK) {
			printk(KERN_ERR "mesh: parity error, target %d\n",
			       ms->conn_tgt);
			ms->stat = DID_PARITY;
		}
		count = (mr->count_hi << 8) + mr->count_lo;
		if (count == 0) {
			cmd_complete(ms);
		} else {
			/* reissue the data transfer command */
			out_8(&mr->sequence, mr->sequence);
		}
		return;
	}
	if (err & ERR_SEQERR) {
		if (exc & EXC_RESELECTED) {
			/* This can happen if we issue a command to
			   get the bus just after the target reselects us. */
			static int mesh_resel_seqerr;
			mesh_resel_seqerr++;
			reselected(ms);
			return;
		}
		if (exc == EXC_PHASEMM) {
			static int mesh_phasemm_seqerr;
			mesh_phasemm_seqerr++;
			phase_mismatch(ms);
			return;
		}
		printk(KERN_ERR "mesh: sequence error (err=%x exc=%x)\n",
		       err, exc);
	} else {
		printk(KERN_ERR "mesh: unknown error %x (exc=%x)\n", err, exc);
	}
	mesh_dump_regs(ms);
	dumplog(ms, ms->conn_tgt);
	if (ms->phase > selecting && (in_8(&mr->bus_status1) & BS1_BSY)) {
		/* try to do what the target wants */
		do_abort(ms);
		phase_mismatch(ms);
		return;
	}
	ms->stat = DID_ERROR;
	mesh_done(ms, 1);
}

static void handle_exception(struct mesh_state *ms)
{
	int exc;
	volatile struct mesh_regs __iomem *mr = ms->mesh;

	exc = in_8(&mr->exception);
	out_8(&mr->interrupt, INT_EXCEPTION | INT_CMDDONE);
	if (exc & EXC_RESELECTED) {
		static int mesh_resel_exc;
		mesh_resel_exc++;
		reselected(ms);
	} else if (exc == EXC_ARBLOST) {
		printk(KERN_DEBUG "mesh: lost arbitration\n");
		ms->stat = DID_BUS_BUSY;
		mesh_done(ms, 1);
	} else if (exc == EXC_SELTO) {
		/* selection timed out */
		ms->stat = DID_BAD_TARGET;
		mesh_done(ms, 1);
	} else if (exc == EXC_PHASEMM) {
		/* target wants to do something different:
		   find out what it wants and do it. */
		phase_mismatch(ms);
	} else {
		printk(KERN_ERR "mesh: can't cope with exception %x\n", exc);
		mesh_dump_regs(ms);
		dumplog(ms, ms->conn_tgt);
		do_abort(ms);
		phase_mismatch(ms);
	}
}

static void handle_msgin(struct mesh_state *ms)
{
	int i, code;
	struct scsi_cmnd *cmd = ms->current_req;
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];

	if (ms->n_msgin == 0)
		return;
	code = ms->msgin[0];
	if (ALLOW_DEBUG(ms->conn_tgt)) {
		printk(KERN_DEBUG "got %d message bytes:", ms->n_msgin);
		for (i = 0; i < ms->n_msgin; ++i)
			printk(" %x", ms->msgin[i]);
		printk("\n");
	}
	dlog(ms, "msgin msg=%.8x",
	     MKWORD(ms->n_msgin, code, ms->msgin[1], ms->msgin[2]));

	ms->expect_reply = 0;
	ms->n_msgout = 0;
	if (ms->n_msgin < msgin_length(ms))
		goto reject;
	if (cmd)
		cmd->SCp.Message = code;
	switch (code) {
	case COMMAND_COMPLETE:
		break;
	case EXTENDED_MESSAGE:
		switch (ms->msgin[2]) {
		case EXTENDED_MODIFY_DATA_POINTER:
			ms->data_ptr += (ms->msgin[3] << 24) + ms->msgin[6]
				+ (ms->msgin[4] << 16) + (ms->msgin[5] << 8);
			break;
		case EXTENDED_SDTR:
			if (tp->sdtr_state != sdtr_sent) {
				/* reply with an SDTR */
				add_sdtr_msg(ms);
				/* limit period to at least his value,
				   offset to no more than his */
				if (ms->msgout[3] < ms->msgin[3])
					ms->msgout[3] = ms->msgin[3];
				if (ms->msgout[4] > ms->msgin[4])
					ms->msgout[4] = ms->msgin[4];
				set_sdtr(ms, ms->msgout[3], ms->msgout[4]);
				ms->msgphase = msg_out;
			} else {
				set_sdtr(ms, ms->msgin[3], ms->msgin[4]);
			}
			break;
		default:
			goto reject;
		}
		break;
	case SAVE_POINTERS:
		tp->saved_ptr = ms->data_ptr;
		break;
	case RESTORE_POINTERS:
		ms->data_ptr = tp->saved_ptr;
		break;
	case DISCONNECT:
		ms->phase = disconnecting;
		break;
	case ABORT:
		break;
	case MESSAGE_REJECT:
		if (tp->sdtr_state == sdtr_sent)
			set_sdtr(ms, 0, 0);
		break;
	case NOP:
		break;
	default:
		if (IDENTIFY_BASE <= code && code <= IDENTIFY_BASE + 7) {
			if (cmd == NULL) {
				do_abort(ms);
				ms->msgphase = msg_out;
			} else if (code != cmd->device->lun + IDENTIFY_BASE) {
				printk(KERN_WARNING "mesh: lun mismatch "
				       "(%d != %d) on reselection from "
				       "target %d\n", code - IDENTIFY_BASE,
				       cmd->device->lun, ms->conn_tgt);
			}
			break;
		}
		goto reject;
	}
	return;

 reject:
	printk(KERN_WARNING "mesh: rejecting message from target %d:",
	       ms->conn_tgt);
	for (i = 0; i < ms->n_msgin; ++i)
		printk(" %x", ms->msgin[i]);
	printk("\n");
	ms->msgout[0] = MESSAGE_REJECT;
	ms->n_msgout = 1;
	ms->msgphase = msg_out;
}

/*
 * Set up DMA commands for transferring data.
 */
static void set_dma_cmds(struct mesh_state *ms, struct scsi_cmnd *cmd)
{
	int i, dma_cmd, total, off, dtot;
	struct scatterlist *scl;
	struct dbdma_cmd *dcmds;

	dma_cmd = ms->tgts[ms->conn_tgt].data_goes_out?
		OUTPUT_MORE: INPUT_MORE;
	dcmds = ms->dma_cmds;
	dtot = 0;
	if (cmd) {
		cmd->SCp.this_residual = cmd->request_bufflen;
		if (cmd->use_sg > 0) {
			int nseg;
			total = 0;
			scl = (struct scatterlist *) cmd->buffer;
			off = ms->data_ptr;
			nseg = pci_map_sg(ms->pdev, scl, cmd->use_sg,
					  cmd->sc_data_direction);
			for (i = 0; i <nseg; ++i, ++scl) {
				u32 dma_addr = sg_dma_address(scl);
				u32 dma_len = sg_dma_len(scl);
				
				total += scl->length;
				if (off >= dma_len) {
					off -= dma_len;
					continue;
				}
				if (dma_len > 0xffff)
					panic("mesh: scatterlist element >= 64k");
				st_le16(&dcmds->req_count, dma_len - off);
				st_le16(&dcmds->command, dma_cmd);
				st_le32(&dcmds->phy_addr, dma_addr + off);
				dcmds->xfer_status = 0;
				++dcmds;
				dtot += dma_len - off;
				off = 0;
			}
		} else if (ms->data_ptr < cmd->request_bufflen) {
			dtot = cmd->request_bufflen - ms->data_ptr;
			if (dtot > 0xffff)
				panic("mesh: transfer size >= 64k");
			st_le16(&dcmds->req_count, dtot);
			/* XXX Use pci DMA API here ... */
			st_le32(&dcmds->phy_addr,
				virt_to_phys(cmd->request_buffer) + ms->data_ptr);
			dcmds->xfer_status = 0;
			++dcmds;
		}
	}
	if (dtot == 0) {
		/* Either the target has overrun our buffer,
		   or the caller didn't provide a buffer. */
		static char mesh_extra_buf[64];

		dtot = sizeof(mesh_extra_buf);
		st_le16(&dcmds->req_count, dtot);
		st_le32(&dcmds->phy_addr, virt_to_phys(mesh_extra_buf));
		dcmds->xfer_status = 0;
		++dcmds;
	}
	dma_cmd += OUTPUT_LAST - OUTPUT_MORE;
	st_le16(&dcmds[-1].command, dma_cmd);
	memset(dcmds, 0, sizeof(*dcmds));
	st_le16(&dcmds->command, DBDMA_STOP);
	ms->dma_count = dtot;
}

static void halt_dma(struct mesh_state *ms)
{
	volatile struct dbdma_regs __iomem *md = ms->dma;
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	struct scsi_cmnd *cmd = ms->current_req;
	int t, nb;

	if (!ms->tgts[ms->conn_tgt].data_goes_out) {
		/* wait a little while until the fifo drains */
		t = 50;
		while (t > 0 && in_8(&mr->fifo_count) != 0
		       && (in_le32(&md->status) & ACTIVE) != 0) {
			--t;
			udelay(1);
		}
	}
	out_le32(&md->control, RUN << 16);	/* turn off RUN bit */
	nb = (mr->count_hi << 8) + mr->count_lo;
	dlog(ms, "halt_dma fc/count=%.6x",
	     MKWORD(0, mr->fifo_count, 0, nb));
	if (ms->tgts[ms->conn_tgt].data_goes_out)
		nb += mr->fifo_count;
	/* nb is the number of bytes not yet transferred
	   to/from the target. */
	ms->data_ptr -= nb;
	dlog(ms, "data_ptr %x", ms->data_ptr);
	if (ms->data_ptr < 0) {
		printk(KERN_ERR "mesh: halt_dma: data_ptr=%d (nb=%d, ms=%p)\n",
		       ms->data_ptr, nb, ms);
		ms->data_ptr = 0;
#ifdef MESH_DBG
		dumplog(ms, ms->conn_tgt);
		dumpslog(ms);
#endif /* MESH_DBG */
	} else if (cmd && cmd->request_bufflen != 0 &&
		   ms->data_ptr > cmd->request_bufflen) {
		printk(KERN_DEBUG "mesh: target %d overrun, "
		       "data_ptr=%x total=%x goes_out=%d\n",
		       ms->conn_tgt, ms->data_ptr, cmd->request_bufflen,
		       ms->tgts[ms->conn_tgt].data_goes_out);
	}
	if (cmd->use_sg != 0) {
		struct scatterlist *sg;
		sg = (struct scatterlist *)cmd->request_buffer;
		pci_unmap_sg(ms->pdev, sg, cmd->use_sg, cmd->sc_data_direction);
	}
	ms->dma_started = 0;
}

static void phase_mismatch(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	int phase;

	dlog(ms, "phasemm ch/cl/seq/fc=%.8x",
	     MKWORD(mr->count_hi, mr->count_lo, mr->sequence, mr->fifo_count));
	phase = in_8(&mr->bus_status0) & BS0_PHASE;
	if (ms->msgphase == msg_out_xxx && phase == BP_MSGOUT) {
		/* output the last byte of the message, without ATN */
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGOUT + use_active_neg);
		mesh_flush_io(mr);
		udelay(1);
		out_8(&mr->fifo, ms->msgout[ms->n_msgout-1]);
		ms->msgphase = msg_out_last;
		return;
	}

	if (ms->msgphase == msg_in) {
		get_msgin(ms);
		if (ms->n_msgin)
			handle_msgin(ms);
	}

	if (ms->dma_started)
		halt_dma(ms);
	if (mr->fifo_count) {
		out_8(&mr->sequence, SEQ_FLUSHFIFO);
		mesh_flush_io(mr);
		udelay(1);
	}

	ms->msgphase = msg_none;
	switch (phase) {
	case BP_DATAIN:
		ms->tgts[ms->conn_tgt].data_goes_out = 0;
		ms->phase = dataing;
		break;
	case BP_DATAOUT:
		ms->tgts[ms->conn_tgt].data_goes_out = 1;
		ms->phase = dataing;
		break;
	case BP_COMMAND:
		ms->phase = commanding;
		break;
	case BP_STATUS:
		ms->phase = statusing;
		break;
	case BP_MSGIN:
		ms->msgphase = msg_in;
		ms->n_msgin = 0;
		break;
	case BP_MSGOUT:
		ms->msgphase = msg_out;
		if (ms->n_msgout == 0) {
			if (ms->aborting) {
				do_abort(ms);
			} else {
				if (ms->last_n_msgout == 0) {
					printk(KERN_DEBUG
					       "mesh: no msg to repeat\n");
					ms->msgout[0] = NOP;
					ms->last_n_msgout = 1;
				}
				ms->n_msgout = ms->last_n_msgout;
			}
		}
		break;
	default:
		printk(KERN_DEBUG "mesh: unknown scsi phase %x\n", phase);
		ms->stat = DID_ERROR;
		mesh_done(ms, 1);
		return;
	}

	start_phase(ms);
}

static void cmd_complete(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	struct scsi_cmnd *cmd = ms->current_req;
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
	int seq, n, t;

	dlog(ms, "cmd_complete fc=%x", mr->fifo_count);
	seq = use_active_neg + (ms->n_msgout? SEQ_ATN: 0);
	switch (ms->msgphase) {
	case msg_out_xxx:
		/* huh?  we expected a phase mismatch */
		ms->n_msgin = 0;
		ms->msgphase = msg_in;
		/* fall through */

	case msg_in:
		/* should have some message bytes in fifo */
		get_msgin(ms);
		n = msgin_length(ms);
		if (ms->n_msgin < n) {
			out_8(&mr->count_lo, n - ms->n_msgin);
			out_8(&mr->sequence, SEQ_MSGIN + seq);
		} else {
			ms->msgphase = msg_none;
			handle_msgin(ms);
			start_phase(ms);
		}
		break;

	case msg_in_bad:
		out_8(&mr->sequence, SEQ_FLUSHFIFO);
		mesh_flush_io(mr);
		udelay(1);
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGIN + SEQ_ATN + use_active_neg);
		break;

	case msg_out:
		/*
		 * To get the right timing on ATN wrt ACK, we have
		 * to get the MESH to drop ACK, wait until REQ gets
		 * asserted, then drop ATN.  To do this we first
		 * issue a SEQ_MSGOUT with ATN and wait for REQ,
		 * then change the command to a SEQ_MSGOUT w/o ATN.
		 * If we don't see REQ in a reasonable time, we
		 * change the command to SEQ_MSGIN with ATN,
		 * wait for the phase mismatch interrupt, then
		 * issue the SEQ_MSGOUT without ATN.
		 */
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGOUT + use_active_neg + SEQ_ATN);
		t = 30;		/* wait up to 30us */
		while ((in_8(&mr->bus_status0) & BS0_REQ) == 0 && --t >= 0)
			udelay(1);
		dlog(ms, "last_mbyte err/exc/fc/cl=%.8x",
		     MKWORD(mr->error, mr->exception,
			    mr->fifo_count, mr->count_lo));
		if (in_8(&mr->interrupt) & (INT_ERROR | INT_EXCEPTION)) {
			/* whoops, target didn't do what we expected */
			ms->last_n_msgout = ms->n_msgout;
			ms->n_msgout = 0;
			if (in_8(&mr->interrupt) & INT_ERROR) {
				printk(KERN_ERR "mesh: error %x in msg_out\n",
				       in_8(&mr->error));
				handle_error(ms);
				return;
			}
			if (in_8(&mr->exception) != EXC_PHASEMM)
				printk(KERN_ERR "mesh: exc %x in msg_out\n",
				       in_8(&mr->exception));
			else
				printk(KERN_DEBUG "mesh: bs0=%x in msg_out\n",
				       in_8(&mr->bus_status0));
			handle_exception(ms);
			return;
		}
		if (in_8(&mr->bus_status0) & BS0_REQ) {
			out_8(&mr->sequence, SEQ_MSGOUT + use_active_neg);
			mesh_flush_io(mr);
			udelay(1);
			out_8(&mr->fifo, ms->msgout[ms->n_msgout-1]);
			ms->msgphase = msg_out_last;
		} else {
			out_8(&mr->sequence, SEQ_MSGIN + use_active_neg + SEQ_ATN);
			ms->msgphase = msg_out_xxx;
		}
		break;

	case msg_out_last:
		ms->last_n_msgout = ms->n_msgout;
		ms->n_msgout = 0;
		ms->msgphase = ms->expect_reply? msg_in: msg_none;
		start_phase(ms);
		break;

	case msg_none:
		switch (ms->phase) {
		case idle:
			printk(KERN_ERR "mesh: interrupt in idle phase?\n");
			dumpslog(ms);
			return;
		case selecting:
			dlog(ms, "Selecting phase at command completion",0);
			ms->msgout[0] = IDENTIFY(ALLOW_RESEL(ms->conn_tgt),
						 (cmd? cmd->device->lun: 0));
			ms->n_msgout = 1;
			ms->expect_reply = 0;
			if (ms->aborting) {
				ms->msgout[0] = ABORT;
				ms->n_msgout++;
			} else if (tp->sdtr_state == do_sdtr) {
				/* add SDTR message */
				add_sdtr_msg(ms);
				ms->expect_reply = 1;
				tp->sdtr_state = sdtr_sent;
			}
			ms->msgphase = msg_out;
			/*
			 * We need to wait for REQ before dropping ATN.
			 * We wait for at most 30us, then fall back to
			 * a scheme where we issue a SEQ_COMMAND with ATN,
			 * which will give us a phase mismatch interrupt
			 * when REQ does come, and then we send the message.
			 */
			t = 230;		/* wait up to 230us */
			while ((in_8(&mr->bus_status0) & BS0_REQ) == 0) {
				if (--t < 0) {
					dlog(ms, "impatient for req", ms->n_msgout);
					ms->msgphase = msg_none;
					break;
				}
				udelay(1);
			}
			break;
		case dataing:
			if (ms->dma_count != 0) {
				start_phase(ms);
				return;
			}
			/*
			 * We can get a phase mismatch here if the target
			 * changes to the status phase, even though we have
			 * had a command complete interrupt.  Then, if we
			 * issue the SEQ_STATUS command, we'll get a sequence
			 * error interrupt.  Which isn't so bad except that
			 * occasionally the mesh actually executes the
			 * SEQ_STATUS *as well as* giving us the sequence
			 * error and phase mismatch exception.
			 */
			out_8(&mr->sequence, 0);
			out_8(&mr->interrupt,
			      INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
			halt_dma(ms);
			break;
		case statusing:
			if (cmd) {
				cmd->SCp.Status = mr->fifo;
				if (DEBUG_TARGET(cmd))
					printk(KERN_DEBUG "mesh: status is %x\n",
					       cmd->SCp.Status);
			}
			ms->msgphase = msg_in;
			break;
		case busfreeing:
			mesh_done(ms, 1);
			return;
		case disconnecting:
			ms->current_req = NULL;
			ms->phase = idle;
			mesh_start(ms);
			return;
		default:
			break;
		}
		++ms->phase;
		start_phase(ms);
		break;
	}
}


/*
 * Called by midlayer with host locked to queue a new
 * request
 */
static int mesh_queue(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
	struct mesh_state *ms;

	cmd->scsi_done = done;
	cmd->host_scribble = NULL;

	ms = (struct mesh_state *) cmd->device->host->hostdata;

	if (ms->request_q == NULL)
		ms->request_q = cmd;
	else
		ms->request_qtail->host_scribble = (void *) cmd;
	ms->request_qtail = cmd;

	if (ms->phase == idle)
		mesh_start(ms);

	return 0;
}

/*
 * Called to handle interrupts, either call by the interrupt
 * handler (do_mesh_interrupt) or by other functions in
 * exceptional circumstances
 */
static void mesh_interrupt(int irq, void *dev_id, struct pt_regs *ptregs)
{
	struct mesh_state *ms = (struct mesh_state *) dev_id;
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	int intr;

#if 0
	if (ALLOW_DEBUG(ms->conn_tgt))
		printk(KERN_DEBUG "mesh_intr, bs0=%x int=%x exc=%x err=%x "
		       "phase=%d msgphase=%d\n", mr->bus_status0,
		       mr->interrupt, mr->exception, mr->error,
		       ms->phase, ms->msgphase);
#endif
	while ((intr = in_8(&mr->interrupt)) != 0) {
		dlog(ms, "interrupt intr/err/exc/seq=%.8x", 
		     MKWORD(intr, mr->error, mr->exception, mr->sequence));
		if (intr & INT_ERROR) {
			handle_error(ms);
		} else if (intr & INT_EXCEPTION) {
			handle_exception(ms);
		} else if (intr & INT_CMDDONE) {
			out_8(&mr->interrupt, INT_CMDDONE);
			cmd_complete(ms);
		}
	}
}

/* Todo: here we can at least try to remove the command from the
 * queue if it isn't connected yet, and for pending command, assert
 * ATN until the bus gets freed.
 */
static int mesh_abort(struct scsi_cmnd *cmd)
{
	struct mesh_state *ms = (struct mesh_state *) cmd->device->host->hostdata;

	printk(KERN_DEBUG "mesh_abort(%p)\n", cmd);
	mesh_dump_regs(ms);
	dumplog(ms, cmd->device->id);
	dumpslog(ms);
	return FAILED;
}

/*
 * Called by the midlayer with the lock held to reset the
 * SCSI host and bus.
 * The midlayer will wait for devices to come back, we don't need
 * to do that ourselves
 */
static int mesh_host_reset(struct scsi_cmnd *cmd)
{
	struct mesh_state *ms = (struct mesh_state *) cmd->device->host->hostdata;
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	volatile struct dbdma_regs __iomem *md = ms->dma;
	unsigned long flags;

	printk(KERN_DEBUG "mesh_host_reset\n");

	spin_lock_irqsave(ms->host->host_lock, flags);

	/* Reset the controller & dbdma channel */
	out_le32(&md->control, (RUN|PAUSE|FLUSH|WAKE) << 16);	/* stop dma */
	out_8(&mr->exception, 0xff);	/* clear all exception bits */
	out_8(&mr->error, 0xff);	/* clear all error bits */
	out_8(&mr->sequence, SEQ_RESETMESH);
       	mesh_flush_io(mr);
	udelay(1);
	out_8(&mr->intr_mask, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
	out_8(&mr->source_id, ms->host->this_id);
	out_8(&mr->sel_timeout, 25);	/* 250ms */
	out_8(&mr->sync_params, ASYNC_PARAMS);

	/* Reset the bus */
	out_8(&mr->bus_status1, BS1_RST);	/* assert RST */
       	mesh_flush_io(mr);
	udelay(30);			/* leave it on for >= 25us */
	out_8(&mr->bus_status1, 0);	/* negate RST */

	/* Complete pending commands */
	handle_reset(ms);
	
	spin_unlock_irqrestore(ms->host->host_lock, flags);
	return SUCCESS;
}

static void set_mesh_power(struct mesh_state *ms, int state)
{
	if (_machine != _MACH_Pmac)
		return;
	if (state) {
		pmac_call_feature(PMAC_FTR_MESH_ENABLE, macio_get_of_node(ms->mdev), 0, 1);
		msleep(200);
	} else {
		pmac_call_feature(PMAC_FTR_MESH_ENABLE, macio_get_of_node(ms->mdev), 0, 0);
		msleep(10);
	}
}			


#ifdef CONFIG_PM
static int mesh_suspend(struct macio_dev *mdev, pm_message_t state)
{
	struct mesh_state *ms = (struct mesh_state *)macio_get_drvdata(mdev);
	unsigned long flags;

	if (state == mdev->ofdev.dev.power.power_state || state < 2)
		return 0;

	scsi_block_requests(ms->host);
	spin_lock_irqsave(ms->host->host_lock, flags);
	while(ms->phase != idle) {
		spin_unlock_irqrestore(ms->host->host_lock, flags);
		msleep(10);
		spin_lock_irqsave(ms->host->host_lock, flags);
	}
	ms->phase = sleeping;
	spin_unlock_irqrestore(ms->host->host_lock, flags);
	disable_irq(ms->meshintr);
	set_mesh_power(ms, 0);

	mdev->ofdev.dev.power.power_state = state;

	return 0;
}

static int mesh_resume(struct macio_dev *mdev)
{
	struct mesh_state *ms = (struct mesh_state *)macio_get_drvdata(mdev);
	unsigned long flags;

	if (mdev->ofdev.dev.power.power_state == 0)
		return 0;

	set_mesh_power(ms, 1);
	mesh_init(ms);
	spin_lock_irqsave(ms->host->host_lock, flags);
	mesh_start(ms);
	spin_unlock_irqrestore(ms->host->host_lock, flags);
	enable_irq(ms->meshintr);
	scsi_unblock_requests(ms->host);

	mdev->ofdev.dev.power.power_state = 0;

	return 0;
}

#endif /* CONFIG_PM */

/*
 * If we leave drives set for synchronous transfers (especially
 * CDROMs), and reboot to MacOS, it gets confused, poor thing.
 * So, on reboot we reset the SCSI bus.
 */
static int mesh_shutdown(struct macio_dev *mdev)
{
	struct mesh_state *ms = (struct mesh_state *)macio_get_drvdata(mdev);
	volatile struct mesh_regs __iomem *mr;
	unsigned long flags;

       	printk(KERN_INFO "resetting MESH scsi bus(es)\n");
	spin_lock_irqsave(ms->host->host_lock, flags);
       	mr = ms->mesh;
	out_8(&mr->intr_mask, 0);
	out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
	out_8(&mr->bus_status1, BS1_RST);
	mesh_flush_io(mr);
	udelay(30);
	out_8(&mr->bus_status1, 0);
	spin_unlock_irqrestore(ms->host->host_lock, flags);

	return 0;
}

static struct scsi_host_template mesh_template = {
	.proc_name			= "mesh",
	.name				= "MESH",
	.queuecommand			= mesh_queue,
	.eh_abort_handler		= mesh_abort,
	.eh_host_reset_handler		= mesh_host_reset,
	.can_queue			= 20,
	.this_id			= 7,
	.sg_tablesize			= SG_ALL,
	.cmd_per_lun			= 2,
	.use_clustering			= DISABLE_CLUSTERING,
};

static int mesh_probe(struct macio_dev *mdev, const struct of_device_id *match)
{
	struct device_node *mesh = macio_get_of_node(mdev);
	struct pci_dev* pdev = macio_get_pci_dev(mdev);
	int tgt, *cfp, minper;
	struct mesh_state *ms;
	struct Scsi_Host *mesh_host;
	void *dma_cmd_space;
	dma_addr_t dma_cmd_bus;

	switch (mdev->bus->chip->type) {
	case macio_heathrow:
	case macio_gatwick:
	case macio_paddington:
		use_active_neg = 0;
		break;
	default:
		use_active_neg = SEQ_ACTIVE_NEG;
	}

	if (macio_resource_count(mdev) != 2 || macio_irq_count(mdev) != 2) {
       		printk(KERN_ERR "mesh: expected 2 addrs and 2 intrs"
	       	       " (got %d,%d)\n", mesh->n_addrs, mesh->n_intrs);
		return -ENODEV;
	}

	if (macio_request_resources(mdev, "mesh") != 0) {
       		printk(KERN_ERR "mesh: unable to request memory resources");
		return -EBUSY;
	}
       	mesh_host = scsi_host_alloc(&mesh_template, sizeof(struct mesh_state));
	if (mesh_host == NULL) {
		printk(KERN_ERR "mesh: couldn't register host");
		goto out_release;
	}
	
	/* Old junk for root discovery, that will die ultimately */
#if !defined(MODULE)
       	note_scsi_host(mesh, mesh_host);
#endif

	mesh_host->base = macio_resource_start(mdev, 0);
	mesh_host->irq = macio_irq(mdev, 0);
       	ms = (struct mesh_state *) mesh_host->hostdata;
	macio_set_drvdata(mdev, ms);
	ms->host = mesh_host;
	ms->mdev = mdev;
	ms->pdev = pdev;
	
	ms->mesh = ioremap(macio_resource_start(mdev, 0), 0x1000);
	if (ms->mesh == NULL) {
		printk(KERN_ERR "mesh: can't map registers\n");
		goto out_free;
	}		
	ms->dma = ioremap(macio_resource_start(mdev, 1), 0x1000);
	if (ms->dma == NULL) {
		printk(KERN_ERR "mesh: can't map registers\n");
		iounmap(ms->mesh);
		goto out_free;
	}

       	ms->meshintr = macio_irq(mdev, 0);
       	ms->dmaintr = macio_irq(mdev, 1);

       	/* Space for dma command list: +1 for stop command,
       	 * +1 to allow for aligning.
	 */
	ms->dma_cmd_size = (mesh_host->sg_tablesize + 2) * sizeof(struct dbdma_cmd);

	/* We use the PCI APIs for now until the generic one gets fixed
	 * enough or until we get some macio-specific versions
	 */
	dma_cmd_space = pci_alloc_consistent(macio_get_pci_dev(mdev),
					     ms->dma_cmd_size,
					     &dma_cmd_bus);
	if (dma_cmd_space == NULL) {
		printk(KERN_ERR "mesh: can't allocate DMA table\n");
		goto out_unmap;
	}
	memset(dma_cmd_space, 0, ms->dma_cmd_size);

	ms->dma_cmds = (struct dbdma_cmd *) DBDMA_ALIGN(dma_cmd_space);
       	ms->dma_cmd_space = dma_cmd_space;
	ms->dma_cmd_bus = dma_cmd_bus + ((unsigned long)ms->dma_cmds)
		- (unsigned long)dma_cmd_space;
	ms->current_req = NULL;
       	for (tgt = 0; tgt < 8; ++tgt) {
	       	ms->tgts[tgt].sdtr_state = do_sdtr;
	       	ms->tgts[tgt].sync_params = ASYNC_PARAMS;
	       	ms->tgts[tgt].current_req = NULL;
       	}

	if ((cfp = (int *) get_property(mesh, "clock-frequency", NULL)))
       		ms->clk_freq = *cfp;
	else {
       		printk(KERN_INFO "mesh: assuming 50MHz clock frequency\n");
	       	ms->clk_freq = 50000000;
       	}

       	/* The maximum sync rate is clock / 5; increase
       	 * mesh_sync_period if necessary.
	 */
	minper = 1000000000 / (ms->clk_freq / 5); /* ns */
	if (mesh_sync_period < minper)
		mesh_sync_period = minper;

	/* Power up the chip */
	set_mesh_power(ms, 1);

	/* Set it up */
       	mesh_init(ms);

	/* XXX FIXME: error should be fatal */
       	if (request_irq(ms->meshintr, do_mesh_interrupt, 0, "MESH", ms))
	       	printk(KERN_ERR "MESH: can't get irq %d\n", ms->meshintr);

	/* XXX FIXME: handle failure */
	scsi_add_host(mesh_host, &mdev->ofdev.dev);
	scsi_scan_host(mesh_host);

	return 0;

out_unmap:
	iounmap(ms->dma);
	iounmap(ms->mesh);
out_free:
	scsi_host_put(mesh_host);
out_release:
	macio_release_resources(mdev);

	return -ENODEV;
}

static int mesh_remove(struct macio_dev *mdev)
{
	struct mesh_state *ms = (struct mesh_state *)macio_get_drvdata(mdev);
	struct Scsi_Host *mesh_host = ms->host;

	scsi_remove_host(mesh_host);

	free_irq(ms->meshintr, ms);

	/* Reset scsi bus */
	mesh_shutdown(mdev);

	/* Shut down chip & termination */
	set_mesh_power(ms, 0);

	/* Unmap registers & dma controller */
	iounmap(ms->mesh);
       	iounmap(ms->dma);

	/* Free DMA commands memory */
	pci_free_consistent(macio_get_pci_dev(mdev), ms->dma_cmd_size,
			  ms->dma_cmd_space, ms->dma_cmd_bus);

	/* Release memory resources */
	macio_release_resources(mdev);

	scsi_host_put(mesh_host);

	return 0;
}


static struct of_device_id mesh_match[] = 
{
	{
	.name 		= "mesh",
	},
	{
	.type		= "scsi",
	.compatible	= "chrp,mesh0"
	},
	{},
};
MODULE_DEVICE_TABLE (of, mesh_match);

static struct macio_driver mesh_driver = 
{
	.name 		= "mesh",
	.match_table	= mesh_match,
	.probe		= mesh_probe,
	.remove		= mesh_remove,
	.shutdown	= mesh_shutdown,
#ifdef CONFIG_PM
	.suspend	= mesh_suspend,
	.resume		= mesh_resume,
#endif
};


static int __init init_mesh(void)
{

	/* Calculate sync rate from module parameters */
	if (sync_rate > 10)
		sync_rate = 10;
	if (sync_rate > 0) {
		printk(KERN_INFO "mesh: configured for synchronous %d MB/s\n", sync_rate);
		mesh_sync_period = 1000 / sync_rate;	/* ns */
		mesh_sync_offset = 15;
	} else
		printk(KERN_INFO "mesh: configured for asynchronous\n");

	return macio_register_driver(&mesh_driver);
}

static void __exit exit_mesh(void)
{
	return macio_unregister_driver(&mesh_driver);
}

module_init(init_mesh);
module_exit(exit_mesh);