summaryrefslogtreecommitdiff
path: root/drivers/acorn/block/fd1772.c
blob: 674bf81c6e660040ab8d0136ecebd4e9f84aad66 (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
/*
 *  linux/kernel/arch/arm/drivers/block/fd1772.c
 *  Based on ataflop.c in the m68k Linux
 *  Copyright (C) 1993  Greg Harp
 *  Atari Support by Bjoern Brauel, Roman Hodek
 *  Archimedes Support by Dave Gilbert (linux@treblig.org)
 *
 *  Big cleanup Sep 11..14 1994 Roman Hodek:
 *   - Driver now works interrupt driven
 *   - Support for two drives; should work, but I cannot test that :-(
 *   - Reading is done in whole tracks and buffered to speed up things
 *   - Disk change detection and drive deselecting after motor-off
 *     similar to TOS
 *   - Autodetection of disk format (DD/HD); untested yet, because I
 *     don't have an HD drive :-(
 *
 *  Fixes Nov 13 1994 Martin Schaller:
 *   - Autodetection works now
 *   - Support for 5 1/4" disks
 *   - Removed drive type (unknown on atari)
 *   - Do seeks with 8 Mhz
 *
 *  Changes by Andreas Schwab:
 *   - After errors in multiple read mode try again reading single sectors
 *  (Feb 1995):
 *   - Clean up error handling
 *   - Set blk_size for proper size checking
 *   - Initialize track register when testing presence of floppy
 *   - Implement some ioctl's
 *
 *  Changes by Torsten Lang:
 *   - When probing the floppies we should add the FDC1772CMDADD_H flag since
 *     the FDC1772 will otherwise wait forever when no disk is inserted...
 *
 *  Things left to do:
 *   - Formatting
 *   - Maybe a better strategy for disk change detection (does anyone
 *     know one?)
 *   - There are some strange problems left: The strangest one is
 *     that, at least on my TT (4+4MB), the first 2 Bytes of the last
 *     page of the TT-Ram (!) change their contents (some bits get
 *     set) while a floppy DMA is going on. But there are no accesses
 *     to these memory locations from the kernel... (I tested that by
 *     making the page read-only). I cannot explain what's going on...
 *   - Sometimes the drive-change-detection stops to work. The
 *     function is still called, but the WP bit always reads as 0...
 *     Maybe a problem with the status reg mode or a timing problem.
 *     Note 10/12/94: The change detection now seems to work reliably.
 *     There is no proof, but I've seen no hang for a long time...
 *
 * ARCHIMEDES changes: (gilbertd@cs.man.ac.uk)
 *     26/12/95 - Changed all names starting with FDC to FDC1772
 *                Removed all references to clock speed of FDC - we're stuck with 8MHz
 *                Modified disk_type structure to remove HD formats
 *
 *      7/ 1/96 - Wrote FIQ code, removed most remaining atariisms
 *
 *     13/ 1/96 - Well I think its read a single sector; but there is a problem
 *                fd_rwsec_done which is called in FIQ mode starts another transfer
 *                off (in fd_rwsec) while still in FIQ mode.  Because its still in
 *                FIQ mode it can't service the DMA and loses data. So need to
 *                heavily restructure.
 *     14/ 1/96 - Found that the definitions of the register numbers of the
 *                FDC were multiplied by 2 in the header for the 16bit words
 *                of the atari so half the writes were going in the wrong place.
 *                Also realised that the FIQ entry didn't make any attempt to
 *                preserve registers or return correctly; now in assembler.
 *
 *     11/ 2/96 - Hmm - doesn't work on real machine.  Auto detect doesn't
 *                and hacking that past seems to wait forever - check motor
 *                being turned on.
 *
 *     17/ 2/96 - still having problems - forcing track to -1 when selecting
 *                new drives seems to allow it to read first few sectors
 *                but then we get solid hangs at apparently random places
 *                which change depending what is happening.
 *
 *      9/ 3/96 - Fiddled a lot of stuff around to move to kernel 1.3.35
 *                A lot of fiddling in DMA stuff. Having problems with it
 *                constnatly thinking its timeing out. Ah - its timeout
 *                was set to (6*HZ) rather than jiffies+(6*HZ).  Now giving
 *                duff data!
 *
 *      5/ 4/96 - Made it use the new IOC_ macros rather than *ioc
 *                Hmm - giving unexpected FIQ and then timeouts
 *     18/ 8/96 - Ran through indent -kr -i8
 *                Some changes to disc change detect; don't know how well it
 *                works.
 *     24/ 8/96 - Put all the track buffering code back in from the atari
 *                code - I wonder if it will still work... No :-)
 *                Still works if I turn off track buffering.
 *     25/ 8/96 - Changed the timer expires that I'd added back to be 
 *                jiffies + ....; and it all sprang to life! Got 2.8K/sec
 *                off a cp -r of a 679K disc (showed 94% cpu usage!)
 *                (PC gets 14.3K/sec - 0% CPU!) Hmm - hard drive corrupt!
 *                Also perhaps that compile was with cache off.
 *                changed cli in fd_readtrack_check to cliIF
 *                changed vmallocs to kmalloc (whats the difference!!)
 *                Removed the busy wait loop in do_fd_request and replaced
 *                by a routine on tq_immediate; only 11% cpu on a dd off the
 *                raw disc - but the speed is the same.
 *	1/ 9/96 - Idea (failed!) - set the 'disable spin-up sequence'
 *		  when we read the track if we know the motor is on; didn't
 *		  help - perhaps we have to do it in stepping as well.
 *		  Nope. Still doesn't help.
 *		  Hmm - what seems to be happening is that fd_readtrack_check
 *		  is never getting called. Its job is to terminate the read
 *		  just after we think we should have got the data; otherwise
 *		  the fdc takes 1 second to timeout; which is what's happening
 *		  Now I can see 'readtrack_timer' being set (which should do the
 *		  call); but it never seems to be called - hmm!
 *		  OK - I've moved the check to my tq_immediate code -
 *		  and it WORKS! 13.95K/second at 19% CPU.
 *		  I wish I knew why that timer didn't work.....
 *
 *     16/11/96 - Fiddled and frigged for 2.0.18
 *
 * DAG 30/01/99 - Started frobbing for 2.2.1
 * DAG 20/06/99 - A little more frobbing:
 *		  Included include/asm/uaccess.h for get_user/put_user
 *
 * DAG  1/09/00 - Dusted off for 2.4.0-test7
 *                MAX_SECTORS was name clashing so it is now FD1772_...
 *                Minor parameter, name layouts for 2.4.x differences
 */

#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <linux/fd.h>
#include <linux/fd1772.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/bitops.h>

#include <asm/arch/oldlatches.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/hardware/ioc.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mach-types.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>


/* Note: FD_MAX_UNITS could be redefined to 2 for the Atari (with
 * little additional rework in this file). But I'm not yet sure if
 * some other code depends on the number of floppies... (It is defined
 * in a public header!)
 */
#if 0
#undef FD_MAX_UNITS
#define	FD_MAX_UNITS	2
#endif

/* Ditto worries for Arc - DAG */
#define FD_MAX_UNITS 4
#define TRACKBUFFER 0
/*#define DEBUG*/

#ifdef DEBUG
#define DPRINT(a)	printk a
#else
#define DPRINT(a)
#endif

static struct request_queue *floppy_queue;

#define MAJOR_NR FLOPPY_MAJOR
#define FLOPPY_DMA 0
#define DEVICE_NAME "floppy"
#define QUEUE (floppy_queue)
#define CURRENT elv_next_request(floppy_queue)

/* Disk types: DD */
static struct archy_disk_type {
	const char *name;
	unsigned spt;		/* sectors per track */
	unsigned blocks;	/* total number of blocks */
	unsigned stretch;	/* track doubling ? */
} disk_type[] = {

	{ "d360", 9, 720, 0 },			/* 360kB diskette */
	{ "D360", 9, 720, 1 },			/* 360kb in 720kb drive */
	{ "D720", 9, 1440, 0 },			/* 720kb diskette (DD) */
	/*{ "D820", 10,1640, 0}, *//* DD disk with 82 tracks/10 sectors 
	                              - DAG - can't see how type detect can distinguish this
				      from 720K until it reads block 4 by which time its too late! */
};

#define	NUM_DISK_TYPES (sizeof(disk_type)/sizeof(*disk_type))

/*
 * Maximum disk size (in kilobytes). This default is used whenever the
 * current disk size is unknown.
 */
#define MAX_DISK_SIZE 720

static struct gendisk *disks[FD_MAX_UNIT];

/* current info on each unit */
static struct archy_floppy_struct {
	int connected;		/* !=0 : drive is connected */
	int autoprobe;		/* !=0 : do autoprobe       */

	struct archy_disk_type *disktype;	/* current type of disk */

	int track;		/* current head position or -1
				   * if unknown */
	unsigned int steprate;	/* steprate setting */
	unsigned int wpstat;	/* current state of WP signal
				   * (for disk change detection) */
} unit[FD_MAX_UNITS];

/* DAG: On Arc we spin on a flag being cleared by fdc1772_comendhandler which
   is an assembler routine */
extern void fdc1772_comendhandler(void);	/* Actually doens't have these parameters - see fd1772.S */
extern volatile int fdc1772_comendstatus;
extern volatile int fdc1772_fdc_int_done;

#define FDC1772BASE ((0x210000>>2)|0x80000000)

#define FDC1772_READ(reg) inb(FDC1772BASE+(reg/2))

/* DAG: You wouldn't be silly to ask why FDC1772_WRITE is a function rather
   than the #def below - well simple - the #def won't compile - and I
   don't understand why (__outwc not defined) */
/* NOTE: Reg is 0,2,4,6 as opposed to 0,1,2,3 or 0,4,8,12 to keep compatibility
   with the ST version of fd1772.h */
/*#define FDC1772_WRITE(reg,val) outw(val,(reg+FDC1772BASE)); */
void FDC1772_WRITE(int reg, unsigned char val)
{
	if (reg == FDC1772REG_CMD) {
		DPRINT(("FDC1772_WRITE new command 0x%x @ %d\n", val,jiffies));
		if (fdc1772_fdc_int_done) {
			DPRINT(("FDC1772_WRITE: Hmm fdc1772_fdc_int_done true - resetting\n"));
			fdc1772_fdc_int_done = 0;
		};
	};
	outb(val, (reg / 2) + FDC1772BASE);
};

#define	FD1772_MAX_SECTORS	22

unsigned char *DMABuffer;	/* buffer for writes */
/*static unsigned long PhysDMABuffer; *//* physical address */
/* DAG: On Arc we just go straight for the DMA buffer */
#define PhysDMABuffer DMABuffer

#ifdef TRACKBUFFER   
unsigned char *TrackBuffer;       /* buffer for reads */
#define PhysTrackBuffer TrackBuffer /* physical address */
static int BufferDrive, BufferSide, BufferTrack;
static int read_track;    /* non-zero if we are reading whole tracks */
  
#define SECTOR_BUFFER(sec)  (TrackBuffer + ((sec)-1)*512)
#define IS_BUFFERED(drive,side,track) \
    (BufferDrive == (drive) && BufferSide == (side) && BufferTrack == (track))
#endif

/*
 * These are global variables, as that's the easiest way to give
 * information to interrupts. They are the data used for the current
 * request.
 */
static int SelectedDrive = 0;
static int ReqCmd, ReqBlock;
static int ReqSide, ReqTrack, ReqSector, ReqCnt;
static int HeadSettleFlag = 0;
static unsigned char *ReqData, *ReqBuffer;
static int MotorOn = 0, MotorOffTrys;

/* Synchronization of FDC1772 access. */
static volatile int fdc_busy = 0;
static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);


/* long req'd for set_bit --RR */
static unsigned long changed_floppies = 0xff, fake_change = 0;
#define	CHECK_CHANGE_DELAY	HZ/2

/* DAG - increased to 30*HZ - not sure if this is the correct thing to do */
#define	FD_MOTOR_OFF_DELAY	(10*HZ)
#define	FD_MOTOR_OFF_MAXTRY	(10*20)

#define FLOPPY_TIMEOUT		(6*HZ)
#define RECALIBRATE_ERRORS	4	/* After this many errors the drive
					 * will be recalibrated. */
#define MAX_ERRORS		8	/* After this many errors the driver
					 * will give up. */

#define	START_MOTOR_OFF_TIMER(delay)				\
	do {							\
		motor_off_timer.expires = jiffies + (delay);	\
		add_timer( &motor_off_timer );			\
		MotorOffTrys = 0;				\
	} while(0)

#define	START_CHECK_CHANGE_TIMER(delay)				\
	do {							\
	        mod_timer(&fd_timer, jiffies + (delay));	\
	} while(0)

#define	START_TIMEOUT()						\
	do {							\
		mod_timer(&timeout_timer, jiffies+FLOPPY_TIMEOUT); \
	} while(0)

#define	STOP_TIMEOUT()						\
	do {							\
		del_timer( &timeout_timer );			\
	} while(0)

#define ENABLE_IRQ() enable_irq(FIQ_FD1772+64);

#define DISABLE_IRQ() disable_irq(FIQ_FD1772+64);

static void fd1772_checkint(void);

DECLARE_WORK(fd1772_tq, (void *)fd1772_checkint, NULL);
/*
 * The driver is trying to determine the correct media format
 * while Probing is set. fd_rwsec_done() clears it after a
 * successful access.
 */
static int Probing = 0;

/* This flag is set when a dummy seek is necessary to make the WP
 * status bit accessible.
 */
static int NeedSeek = 0;


/***************************** Prototypes *****************************/

static void fd_select_side(int side);
static void fd_select_drive(int drive);
static void fd_deselect(void);
static void fd_motor_off_timer(unsigned long dummy);
static void check_change(unsigned long dummy);
static void floppy_irqconsequencehandler(void);
static void fd_error(void);
static void do_fd_action(int drive);
static void fd_calibrate(void);
static void fd_calibrate_done(int status);
static void fd_seek(void);
static void fd_seek_done(int status);
static void fd_rwsec(void);
#ifdef TRACKBUFFER   
static void fd_readtrack_check( unsigned long dummy );  
#endif
static void fd_rwsec_done(int status);
static void fd_times_out(unsigned long dummy);
static void finish_fdc(void);
static void finish_fdc_done(int dummy);
static void floppy_off(unsigned int nr);
static void setup_req_params(int drive);
static void redo_fd_request(void);
static int fd_ioctl(struct inode *inode, struct file *filp, unsigned int
		    cmd, unsigned long param);
static void fd_probe(int drive);
static int fd_test_drive_present(int drive);
static void config_types(void);
static int floppy_open(struct inode *inode, struct file *filp);
static int floppy_release(struct inode *inode, struct file *filp);
static void do_fd_request(request_queue_t *);

/************************* End of Prototypes **************************/

static DEFINE_TIMER(motor_off_timer, fd_motor_off_timer, 0, 0);

#ifdef TRACKBUFFER
static DEFINE_TIMER(readtrack_timer, fd_readtrack_check, 0, 0);
#endif

static DEFINE_TIMER(timeout_timer, fd_times_out, 0, 0);

static DEFINE_TIMER(fd_timer, check_change, 0, 0);

/* DAG: Haven't got a clue what this is? */
int stdma_islocked(void)
{
	return 0;
};

/* Select the side to use. */

static void fd_select_side(int side)
{
	oldlatch_aupdate(LATCHA_SIDESEL, side ? 0 : LATCHA_SIDESEL);
}


/* Select a drive, update the FDC1772's track register
 */

static void fd_select_drive(int drive)
{
#ifdef DEBUG
	printk("fd_select_drive:%d\n", drive);
#endif
	/* Hmm - nowhere do we seem to turn the motor on - I'm going to do it here! */
	oldlatch_aupdate(LATCHA_MOTOR | LATCHA_INUSE, 0);

	if (drive == SelectedDrive)
		return;

	oldlatch_aupdate(LATCHA_FDSELALL, 0xf - (1 << drive));

	/* restore track register to saved value */
	FDC1772_WRITE(FDC1772REG_TRACK, unit[drive].track);
	udelay(25);

	SelectedDrive = drive;
}


/* Deselect both drives. */

static void fd_deselect(void)
{
	unsigned long flags;

	DPRINT(("fd_deselect\n"));

	oldlatch_aupdate(LATCHA_FDSELALL | LATCHA_MOTOR | LATCHA_INUSE, 0xf | LATCHA_MOTOR | LATCHA_INUSE);

	SelectedDrive = -1;
}


/* This timer function deselects the drives when the FDC1772 switched the
 * motor off. The deselection cannot happen earlier because the FDC1772
 * counts the index signals, which arrive only if one drive is selected.
 */

static void fd_motor_off_timer(unsigned long dummy)
{
	unsigned long flags;
	unsigned char status;
	int delay;

	del_timer(&motor_off_timer);

	if (SelectedDrive < 0)
		/* no drive selected, needn't deselect anyone */
		return;

	save_flags(flags);
	cli();

	if (fdc_busy)		/* was stdma_islocked */
		goto retry;

	status = FDC1772_READ(FDC1772REG_STATUS);

	if (!(status & 0x80)) {
		/*
		 * motor already turned off by FDC1772 -> deselect drives
		 * In actual fact its this deselection which turns the motor
		 * off on the Arc, since the motor control is actually on
		 * Latch A
		 */
		DPRINT(("fdc1772: deselecting in fd_motor_off_timer\n"));
		fd_deselect();
		MotorOn = 0;
		restore_flags(flags);
		return;
	}
	/* not yet off, try again */

retry:
	restore_flags(flags);
	/* Test again later; if tested too often, it seems there is no disk
	 * in the drive and the FDC1772 will leave the motor on forever (or,
	 * at least until a disk is inserted). So we'll test only twice
	 * per second from then on...
	 */
	delay = (MotorOffTrys < FD_MOTOR_OFF_MAXTRY) ?
	    (++MotorOffTrys, HZ / 20) : HZ / 2;
	START_MOTOR_OFF_TIMER(delay);
}


/* This function is repeatedly called to detect disk changes (as good
 * as possible) and keep track of the current state of the write protection.
 */

static void check_change(unsigned long dummy)
{
	static int drive = 0;

	unsigned long flags;
	int stat;

	if (fdc_busy)
		return;		/* Don't start poking about if the fdc is busy */

	return;			/* let's just forget it for the mo DAG */

	if (++drive > 1 || !unit[drive].connected)
		drive = 0;

	save_flags(flags);
	cli();

	if (!stdma_islocked()) {
		stat = !!(FDC1772_READ(FDC1772REG_STATUS) & FDC1772STAT_WPROT);

		/* The idea here is that if the write protect line has changed then
		the disc must have changed */
		if (stat != unit[drive].wpstat) {
			DPRINT(("wpstat[%d] = %d\n", drive, stat));
			unit[drive].wpstat = stat;
			set_bit(drive, &changed_floppies);
		}
	}
	restore_flags(flags);

	START_CHECK_CHANGE_TIMER(CHECK_CHANGE_DELAY);
}


/* Handling of the Head Settling Flag: This flag should be set after each
 * seek operation, because we don't use seeks with verify.
 */

static inline void set_head_settle_flag(void)
{
	HeadSettleFlag = FDC1772CMDADD_E;
}

static inline int get_head_settle_flag(void)
{
	int tmp = HeadSettleFlag;
	HeadSettleFlag = 0;
	return (tmp);
}




/* General Interrupt Handling */

static inline void copy_buffer(void *from, void *to)
{
	ulong *p1 = (ulong *) from, *p2 = (ulong *) to;
	int cnt;

	for (cnt = 512 / 4; cnt; cnt--)
		*p2++ = *p1++;
}

static void (*FloppyIRQHandler) (int status) = NULL;

static void floppy_irqconsequencehandler(void)
{
	unsigned char status;
	void (*handler) (int);

	fdc1772_fdc_int_done = 0;

	handler = FloppyIRQHandler;
	FloppyIRQHandler = NULL;

	if (handler) {
		nop();
		status = (unsigned char) fdc1772_comendstatus;
		DPRINT(("FDC1772 irq, status = %02x handler = %08lx\n", (unsigned int) status, (unsigned long) handler));
		handler(status);
	} else {
		DPRINT(("FDC1772 irq, no handler status=%02x\n", fdc1772_comendstatus));
	}
	DPRINT(("FDC1772 irq: end of floppy_irq\n"));
}


/* Error handling: If some error happened, retry some times, then
 * recalibrate, then try again, and fail after MAX_ERRORS.
 */

static void fd_error(void)
{
	printk("FDC1772: fd_error\n");
	/*panic("fd1772: fd_error"); *//* DAG tmp */
	if (!CURRENT)
		return;
	CURRENT->errors++;
	if (CURRENT->errors >= MAX_ERRORS) {
		printk("fd%d: too many errors.\n", SelectedDrive);
		end_request(CURRENT, 0);
	} else if (CURRENT->errors == RECALIBRATE_ERRORS) {
		printk("fd%d: recalibrating\n", SelectedDrive);
		if (SelectedDrive != -1)
			unit[SelectedDrive].track = -1;
	}
	redo_fd_request();
}



#define	SET_IRQ_HANDLER(proc) do { FloppyIRQHandler = (proc); } while(0)


/* do_fd_action() is the general procedure for a fd request: All
 * required parameter settings (drive select, side select, track
 * position) are checked and set if needed. For each of these
 * parameters and the actual reading or writing exist two functions:
 * one that starts the setting (or skips it if possible) and one
 * callback for the "done" interrupt. Each done func calls the next
 * set function to propagate the request down to fd_rwsec_done().
 */

static void do_fd_action(int drive)
{
	struct request *req;
	DPRINT(("do_fd_action unit[drive].track=%d\n", unit[drive].track));

#ifdef TRACKBUFFER
repeat:

	if (IS_BUFFERED( drive, ReqSide, ReqTrack )) {
		req = CURRENT;
		if (ReqCmd == READ) {
			copy_buffer( SECTOR_BUFFER(ReqSector), ReqData );
			if (++ReqCnt < req->current_nr_sectors) {
				/* read next sector */
				setup_req_params( drive );
				goto repeat;
			} else {
				/* all sectors finished */
				req->nr_sectors -= req->current_nr_sectors;
				req->sector += req->current_nr_sectors;
				end_request(req, 1);
				redo_fd_request();
				return;
			}
		} else {
			/* cmd == WRITE, pay attention to track buffer
			 * consistency! */
			copy_buffer( ReqData, SECTOR_BUFFER(ReqSector) );
		}
	}
#endif

	if (SelectedDrive != drive) {
		/*unit[drive].track = -1; DAG */
		fd_select_drive(drive);
	};


	if (unit[drive].track == -1)
		fd_calibrate();
	else if (unit[drive].track != ReqTrack << unit[drive].disktype->stretch)
		fd_seek();
	else
		fd_rwsec();
}


/* Seek to track 0 if the current track is unknown */

static void fd_calibrate(void)
{
	DPRINT(("fd_calibrate\n"));
	if (unit[SelectedDrive].track >= 0) {
		fd_calibrate_done(0);
		return;
	}
	DPRINT(("fd_calibrate (after track compare)\n"));
	SET_IRQ_HANDLER(fd_calibrate_done);
	/* we can't verify, since the speed may be incorrect */
	FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_RESTORE | unit[SelectedDrive].steprate);

	NeedSeek = 1;
	MotorOn = 1;
	START_TIMEOUT();
	/* wait for IRQ */
}


static void fd_calibrate_done(int status)
{
	DPRINT(("fd_calibrate_done()\n"));
	STOP_TIMEOUT();

	/* set the correct speed now */
	if (status & FDC1772STAT_RECNF) {
		printk("fd%d: restore failed\n", SelectedDrive);
		fd_error();
	} else {
		unit[SelectedDrive].track = 0;
		fd_seek();
	}
}


/* Seek the drive to the requested track. The drive must have been
 * calibrated at some point before this.
 */

static void fd_seek(void)
{
	unsigned long flags;
	DPRINT(("fd_seek() to track %d (unit[SelectedDrive].track=%d)\n", ReqTrack,
		unit[SelectedDrive].track));
	if (unit[SelectedDrive].track == ReqTrack <<
	    unit[SelectedDrive].disktype->stretch) {
		fd_seek_done(0);
		return;
	}
	FDC1772_WRITE(FDC1772REG_DATA, ReqTrack <<
		      unit[SelectedDrive].disktype->stretch);
	udelay(25);
	save_flags(flags);
	clf();
	SET_IRQ_HANDLER(fd_seek_done);
	FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_SEEK | unit[SelectedDrive].steprate |
		/* DAG */
		(MotorOn?FDC1772CMDADD_H:0));

	restore_flags(flags);
	MotorOn = 1;
	set_head_settle_flag();
	START_TIMEOUT();
	/* wait for IRQ */
}


static void fd_seek_done(int status)
{
	DPRINT(("fd_seek_done()\n"));
	STOP_TIMEOUT();

	/* set the correct speed */
	if (status & FDC1772STAT_RECNF) {
		printk("fd%d: seek error (to track %d)\n",
		       SelectedDrive, ReqTrack);
		/* we don't know exactly which track we are on now! */
		unit[SelectedDrive].track = -1;
		fd_error();
	} else {
		unit[SelectedDrive].track = ReqTrack <<
		    unit[SelectedDrive].disktype->stretch;
		NeedSeek = 0;
		fd_rwsec();
	}
}


/* This does the actual reading/writing after positioning the head
 * over the correct track.
 */

#ifdef TRACKBUFFER
static int MultReadInProgress = 0;
#endif


static void fd_rwsec(void)
{
	unsigned long paddr, flags;
	unsigned int rwflag, old_motoron;
	unsigned int track;

	DPRINT(("fd_rwsec(), Sec=%d, Access=%c\n", ReqSector, ReqCmd == WRITE ? 'w' : 'r'));
	if (ReqCmd == WRITE) {
		/*cache_push( (unsigned long)ReqData, 512 ); */
		paddr = (unsigned long) ReqData;
		rwflag = 0x100;
	} else {
		paddr = (unsigned long) PhysDMABuffer;
#ifdef TRACKBUFFER
		if (read_track)
			paddr = (unsigned long)PhysTrackBuffer;
#endif
		rwflag = 0;
	}

	DPRINT(("fd_rwsec() before sidesel rwflag=%d sec=%d trk=%d\n", rwflag,
		ReqSector, FDC1772_READ(FDC1772REG_TRACK)));
	fd_select_side(ReqSide);

	/*DPRINT(("fd_rwsec() before start sector \n")); */
	/* Start sector of this operation */
#ifdef TRACKBUFFER
	FDC1772_WRITE( FDC1772REG_SECTOR, !read_track ? ReqSector : 1 );
#else
	FDC1772_WRITE( FDC1772REG_SECTOR, ReqSector );
#endif

	/* Cheat for track if stretch != 0 */
	if (unit[SelectedDrive].disktype->stretch) {
		track = FDC1772_READ(FDC1772REG_TRACK);
		FDC1772_WRITE(FDC1772REG_TRACK, track >>
			      unit[SelectedDrive].disktype->stretch);
	}
	udelay(25);

	DPRINT(("fd_rwsec() before setup DMA \n"));
	/* Setup DMA - Heavily modified by DAG */
	save_flags(flags);
	clf();
	disable_dma(FLOPPY_DMA);
	set_dma_mode(FLOPPY_DMA, rwflag ? DMA_MODE_WRITE : DMA_MODE_READ);
	set_dma_addr(FLOPPY_DMA, (long) paddr);		/* DAG - changed from Atari specific */
#ifdef TRACKBUFFER
	set_dma_count(FLOPPY_DMA,(!read_track ? 1 : unit[SelectedDrive].disktype->spt)*512);
#else
	set_dma_count(FLOPPY_DMA, 512);		/* Block/sector size - going to have to change */
#endif
	SET_IRQ_HANDLER(fd_rwsec_done);
	/* Turn on dma int */
	enable_dma(FLOPPY_DMA);
	/* Now give it something to do */
	FDC1772_WRITE(FDC1772REG_CMD, (rwflag ? (FDC1772CMD_WRSEC | FDC1772CMDADD_P) : 
#ifdef TRACKBUFFER
	      (FDC1772CMD_RDSEC | (read_track ? FDC1772CMDADD_M : 0) |
	      /* Hmm - the idea here is to stop the FDC spinning the disc
	      up when we know that we already still have it spinning */
	      (MotorOn?FDC1772CMDADD_H:0))
#else
	      FDC1772CMD_RDSEC
#endif
		));

	restore_flags(flags);
	DPRINT(("fd_rwsec() after DMA setup flags=0x%08x\n", flags));
	/*sti(); *//* DAG - Hmm */
	/* Hmm - should do something DAG */
	old_motoron = MotorOn;
	MotorOn = 1;
	NeedSeek = 1;

	/* wait for interrupt */

#ifdef TRACKBUFFER
	if (read_track) {
		/*
		 * If reading a whole track, wait about one disk rotation and
		 * then check if all sectors are read. The FDC will even
		 * search for the first non-existant sector and need 1 sec to
		 * recognise that it isn't present :-(
		 */
		/* 1 rot. + 5 rot.s if motor was off  */
		mod_timer(&readtrack_timer, jiffies + HZ/5 + (old_motoron ? 0 : HZ));
		DPRINT(("Setting readtrack_timer to %d @ %d\n",
			readtrack_timer.expires,jiffies));
		MultReadInProgress = 1;
	}
#endif

	/*DPRINT(("fd_rwsec() before START_TIMEOUT \n")); */
	START_TIMEOUT();
	/*DPRINT(("fd_rwsec() after START_TIMEOUT \n")); */
}


#ifdef TRACKBUFFER

static void fd_readtrack_check(unsigned long dummy)
{
	unsigned long flags, addr;
	extern unsigned char *fdc1772_dataaddr;

	DPRINT(("fd_readtrack_check @ %d\n",jiffies));

	save_flags(flags);
	clf();

	del_timer( &readtrack_timer );

	if (!MultReadInProgress) {
		/* This prevents a race condition that could arise if the
		 * interrupt is triggered while the calling of this timer
		 * callback function takes place. The IRQ function then has
		 * already cleared 'MultReadInProgress'  when control flow
		 * gets here.
		 */
		restore_flags(flags);
		return;
	}

	/* get the current DMA address */
	addr=(unsigned long)fdc1772_dataaddr; /* DAG - ? */
	DPRINT(("fd_readtrack_check: addr=%x PhysTrackBuffer=%x\n",addr,PhysTrackBuffer));

	if (addr >= (unsigned int)PhysTrackBuffer + unit[SelectedDrive].disktype->spt*512) {
		/* already read enough data, force an FDC interrupt to stop
		 * the read operation
		 */
		SET_IRQ_HANDLER( NULL );
		restore_flags(flags);
		DPRINT(("fd_readtrack_check(): done\n"));
		FDC1772_WRITE( FDC1772REG_CMD, FDC1772CMD_FORCI );
		udelay(25);

		/* No error until now -- the FDC would have interrupted
		 * otherwise!
		 */
		fd_rwsec_done( 0 );
	} else {
		/* not yet finished, wait another tenth rotation */
		restore_flags(flags);
		DPRINT(("fd_readtrack_check(): not yet finished\n"));
		readtrack_timer.expires = jiffies + HZ/5/10;
		add_timer( &readtrack_timer );
	}
}

#endif

static void fd_rwsec_done(int status)
{
	unsigned int track;

	DPRINT(("fd_rwsec_done() status=%d @ %d\n", status,jiffies));

#ifdef TRACKBUFFER
	if (read_track && !MultReadInProgress)
		return;

	MultReadInProgress = 0;

	STOP_TIMEOUT();

	if (read_track)
		del_timer( &readtrack_timer );
#endif


	/* Correct the track if stretch != 0 */
	if (unit[SelectedDrive].disktype->stretch) {
		track = FDC1772_READ(FDC1772REG_TRACK);
		FDC1772_WRITE(FDC1772REG_TRACK, track <<
			      unit[SelectedDrive].disktype->stretch);
	}
	if (ReqCmd == WRITE && (status & FDC1772STAT_WPROT)) {
		printk("fd%d: is write protected\n", SelectedDrive);
		goto err_end;
	}
	if ((status & FDC1772STAT_RECNF)
#ifdef TRACKBUFFER
	    /* RECNF is no error after a multiple read when the FDC
	     * searched for a non-existant sector!
	     */
	    && !(read_track &&
	       FDC1772_READ(FDC1772REG_SECTOR) > unit[SelectedDrive].disktype->spt)
#endif
	    ) {
		if (Probing) {
			if (unit[SelectedDrive].disktype > disk_type) {
				/* try another disk type */
				unit[SelectedDrive].disktype--;
				set_capacity(disks[SelectedDrive],
				    unit[SelectedDrive].disktype->blocks);
			} else
				Probing = 0;
		} else {
			/* record not found, but not probing. Maybe stretch wrong ? Restart probing */
			if (unit[SelectedDrive].autoprobe) {
				unit[SelectedDrive].disktype = disk_type + NUM_DISK_TYPES - 1;
				set_capacity(disks[SelectedDrive],
				    unit[SelectedDrive].disktype->blocks);
				Probing = 1;
			}
		}
		if (Probing) {
			setup_req_params(SelectedDrive);
#ifdef TRACKBUFFER
			BufferDrive = -1;
#endif
			do_fd_action(SelectedDrive);
			return;
		}
		printk("fd%d: sector %d not found (side %d, track %d)\n",
		       SelectedDrive, FDC1772_READ(FDC1772REG_SECTOR), ReqSide, ReqTrack);
		goto err_end;
	}
	if (status & FDC1772STAT_CRC) {
		printk("fd%d: CRC error (side %d, track %d, sector %d)\n",
		       SelectedDrive, ReqSide, ReqTrack, FDC1772_READ(FDC1772REG_SECTOR));
		goto err_end;
	}
	if (status & FDC1772STAT_LOST) {
		printk("fd%d: lost data (side %d, track %d, sector %d)\n",
		       SelectedDrive, ReqSide, ReqTrack, FDC1772_READ(FDC1772REG_SECTOR));
		goto err_end;
	}
	Probing = 0;

	if (ReqCmd == READ) {
#ifdef TRACKBUFFER
		if (!read_track) {
			/*cache_clear (PhysDMABuffer, 512);*/
			copy_buffer (DMABuffer, ReqData);
		} else {
			/*cache_clear (PhysTrackBuffer, FD1772_MAX_SECTORS * 512);*/
			BufferDrive = SelectedDrive;
			BufferSide  = ReqSide;
			BufferTrack = ReqTrack;
			copy_buffer (SECTOR_BUFFER (ReqSector), ReqData);
		}
#else
		/*cache_clear( PhysDMABuffer, 512 ); */
		copy_buffer(DMABuffer, ReqData);
#endif
	}
	if (++ReqCnt < CURRENT->current_nr_sectors) {
		/* read next sector */
		setup_req_params(SelectedDrive);
		do_fd_action(SelectedDrive);
	} else {
		/* all sectors finished */
		CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
		CURRENT->sector += CURRENT->current_nr_sectors;
		end_request(CURRENT, 1);
		redo_fd_request();
	}
	return;

err_end:
#ifdef TRACKBUFFER
	BufferDrive = -1;
#endif

	fd_error();
}


static void fd_times_out(unsigned long dummy)
{
	SET_IRQ_HANDLER(NULL);
	/* If the timeout occurred while the readtrack_check timer was
	 * active, we need to cancel it, else bad things will happen */
	del_timer( &readtrack_timer ); 
	FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_FORCI);
	udelay(25);

	printk("floppy timeout\n");
	STOP_TIMEOUT();		/* hmm - should we do this ? */
	fd_error();
}


/* The (noop) seek operation here is needed to make the WP bit in the
 * FDC1772 status register accessible for check_change. If the last disk
 * operation would have been a RDSEC, this bit would always read as 0
 * no matter what :-( To save time, the seek goes to the track we're
 * already on.
 */

static void finish_fdc(void)
{
	/* DAG - just try without this dummy seek! */
	finish_fdc_done(0);
	return;

	if (!NeedSeek) {
		finish_fdc_done(0);
	} else {
		DPRINT(("finish_fdc: dummy seek started\n"));
		FDC1772_WRITE(FDC1772REG_DATA, unit[SelectedDrive].track);
		SET_IRQ_HANDLER(finish_fdc_done);
		FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_SEEK);
		MotorOn = 1;
		START_TIMEOUT();
		/* we must wait for the IRQ here, because the ST-DMA is
		 * released immediately afterwards and the interrupt may be
		 * delivered to the wrong driver.
		 */
	}
}


static void finish_fdc_done(int dummy)
{
	unsigned long flags;

	DPRINT(("finish_fdc_done entered\n"));
	STOP_TIMEOUT();
	NeedSeek = 0;

	if (timer_pending(&fd_timer) &&
	    time_after(jiffies + 5, fd_timer.expires)) 
		/* If the check for a disk change is done too early after this
		 * last seek command, the WP bit still reads wrong :-((
		 */
		mod_timer(&fd_timer, jiffies + 5);
	else {
		/*      START_CHECK_CHANGE_TIMER( CHECK_CHANGE_DELAY ); */
	};
	del_timer(&motor_off_timer);
	START_MOTOR_OFF_TIMER(FD_MOTOR_OFF_DELAY);

	save_flags(flags);
	cli();
	/* stdma_release(); - not sure if I should do something DAG  */
	fdc_busy = 0;
	wake_up(&fdc_wait);
	restore_flags(flags);

	DPRINT(("finish_fdc() finished\n"));
}


/* Prevent "aliased" accesses. */
static int fd_ref[4];
static int fd_device[4];

/* dummy for blk.h */
static void floppy_off(unsigned int nr)
{
}


/* On the old arcs write protect depends on the particular model
   of machine.  On the A310, R140, and A440 there is a disc changed
   detect, however on the A4x0/1 range there is not.  There
   is nothing to tell you which machine your on.
   At the moment I'm just marking changed always. I've
   left the Atari's 'change on write protect change' code in this
   part (but nothing sets it).
   RiscOS apparently checks the disc serial number etc. to detect changes
   - but if it sees a disc change line go high (?) it flips to using
   it. Well  maybe I'll add that in the future (!?)
*/
static int check_floppy_change(struct gendisk *disk)
{
	struct archy_floppy_struct *p = disk->private_data;
	unsigned int drive = p - unit;

	if (test_bit(drive, &fake_change)) {
		/* simulated change (e.g. after formatting) */
		return 1;
	}
	if (test_bit(drive, &changed_floppies)) {
		/* surely changed (the WP signal changed at least once) */
		return 1;
	}
	if (p->wpstat) {
		/* WP is on -> could be changed: to be sure, buffers should be
		   * invalidated...
		 */
		return 1;
	}
	return 1; /* DAG - was 0 */
}

static int floppy_revalidate(struct gendisk *disk)
{
	struct archy_floppy_struct *p = disk->private_data;
	unsigned int drive = p - unit;

	if (test_bit(drive, &changed_floppies) || test_bit(drive, &fake_change)
	    || unit[drive].disktype == 0) {
#ifdef TRACKBUFFER
		BufferDrive = -1;
#endif
		clear_bit(drive, &fake_change);
		clear_bit(drive, &changed_floppies);
		p->disktype = 0;
	}
	return 0;
}

/* This sets up the global variables describing the current request. */

static void setup_req_params(int drive)
{
	int block = ReqBlock + ReqCnt;

	ReqTrack = block / unit[drive].disktype->spt;
	ReqSector = block - ReqTrack * unit[drive].disktype->spt + 1;
	ReqSide = ReqTrack & 1;
	ReqTrack >>= 1;
	ReqData = ReqBuffer + 512 * ReqCnt;

#ifdef TRACKBUFFER
	read_track = (ReqCmd == READ && CURRENT->errors == 0);
#endif

	DPRINT(("Request params: Si=%d Tr=%d Se=%d Data=%08lx\n", ReqSide,
		ReqTrack, ReqSector, (unsigned long) ReqData));
}


static void redo_fd_request(void)
{
	int drive, type;
	struct archy_floppy_struct *floppy;

	DPRINT(("redo_fd_request: CURRENT=%p dev=%s CURRENT->sector=%ld\n",
		CURRENT, CURRENT ? CURRENT->rq_disk->disk_name : "",
		CURRENT ? CURRENT->sector : 0));

repeat:

	if (!CURRENT)
		goto the_end;

	floppy = CURRENT->rq_disk->private_data;
	drive = floppy - unit;
	type = fd_device[drive];

	if (!floppy->connected) {
		/* drive not connected */
		printk("Unknown Device: fd%d\n", drive);
		end_request(CURRENT, 0);
		goto repeat;
	}
	if (type == 0) {
		if (!floppy->disktype) {
			Probing = 1;
			floppy->disktype = disk_type + NUM_DISK_TYPES - 1;
			set_capacity(disks[drive], floppy->disktype->blocks);
			floppy->autoprobe = 1;
		}
	} else {
		/* user supplied disk type */
		--type;
		if (type >= NUM_DISK_TYPES) {
			printk("fd%d: invalid disk format", drive);
			end_request(CURRENT, 0);
			goto repeat;
		}
		floppy->disktype = &disk_type[type];
		set_capacity(disks[drive], floppy->disktype->blocks);
		floppy->autoprobe = 0;
	}

	if (CURRENT->sector + 1 > floppy->disktype->blocks) {
		end_request(CURRENT, 0);
		goto repeat;
	}
	/* stop deselect timer */
	del_timer(&motor_off_timer);

	ReqCnt = 0;
	ReqCmd = CURRENT->cmd;
	ReqBlock = CURRENT->sector;
	ReqBuffer = CURRENT->buffer;
	setup_req_params(drive);
	do_fd_action(drive);

	return;

the_end:
	finish_fdc();
}

static void fd1772_checkint(void)
{
	extern int fdc1772_bytestogo;

	/*printk("fd1772_checkint %d\n",fdc1772_fdc_int_done);*/
	if (fdc1772_fdc_int_done)
		floppy_irqconsequencehandler();
	if ((MultReadInProgress) && (fdc1772_bytestogo==0)) fd_readtrack_check(0);
	if (fdc_busy) {
		schedule_work(&fd1772_tq);
	}
}

static void do_fd_request(request_queue_t* q)
{
	unsigned long flags;

	DPRINT(("do_fd_request for pid %d\n", current->pid));
	if (fdc_busy) return;
	save_flags(flags);
	cli();
	wait_event(fdc_wait, !fdc_busy);
	fdc_busy = 1;
	ENABLE_IRQ();
	restore_flags(flags);

	fdc1772_fdc_int_done = 0;

	redo_fd_request();

	schedule_work(&fd1772_tq);
}


static int invalidate_drive(struct block_device *bdev)
{
	struct archy_floppy_struct *p = bdev->bd_disk->private_data;
	/* invalidate the buffer track to force a reread */
#ifdef TRACKBUFFER
	BufferDrive = -1;
#endif

	set_bit(p - unit, &fake_change);
	return 0;
}

static int fd_ioctl(struct inode *inode, struct file *filp,
		    unsigned int cmd, unsigned long param)
{
	struct block_device *bdev = inode->i_bdev;

	switch (cmd) {
	case FDFMTEND:
	case FDFLUSH:
		invalidate_drive(bdev);
		check_disk_change(bdev);
	case FDFMTBEG:
		return 0;
	default:
		return -EINVAL;
	}
}


/* Initialize the 'unit' variable for drive 'drive' */

static void fd_probe(int drive)
{
	unit[drive].connected = 0;
	unit[drive].disktype = NULL;

	if (!fd_test_drive_present(drive))
		return;

	unit[drive].connected = 1;
	unit[drive].track = -1; /* If we put the auto detect back in this can go to 0 */
	unit[drive].steprate = FDC1772STEP_6;
	MotorOn = 1;		/* from probe restore operation! */
}


/* This function tests the physical presence of a floppy drive (not
 * whether a disk is inserted). This is done by issuing a restore
 * command, waiting max. 2 seconds (that should be enough to move the
 * head across the whole disk) and looking at the state of the "TR00"
 * signal. This should now be raised if there is a drive connected
 * (and there is no hardware failure :-) Otherwise, the drive is
 * declared absent.
 */

static int fd_test_drive_present(int drive)
{
	unsigned long timeout;
	unsigned char status;
	int ok;

	printk("fd_test_drive_present %d\n", drive);
	if (drive > 1)
		return (0);
	return (1);		/* Simple hack for the moment - the autodetect doesn't seem to work on arc */
	fd_select_drive(drive);

	/* disable interrupt temporarily */
	DISABLE_IRQ();
	FDC1772_WRITE(FDC1772REG_TRACK, 0x00);	/* was ff00 why? */
	FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_RESTORE | FDC1772CMDADD_H | FDC1772STEP_6);

	/*printk("fd_test_drive_present: Going into timeout loop\n"); */
	for (ok = 0, timeout = jiffies + 2 * HZ + HZ / 2; time_before(jiffies, timeout);) {
		/*  What does this piece of atariism do? - query for an interrupt? */
		/*  if (!(mfp.par_dt_reg & 0x20))
		   break; */
		/* Well this is my nearest guess - quit when we get an FDC interrupt */
		if (ioc_readb(IOC_FIQSTAT) & 2)
			break;
	}

	/*printk("fd_test_drive_present: Coming out of timeout loop\n"); */
	status = FDC1772_READ(FDC1772REG_STATUS);
	ok = (status & FDC1772STAT_TR00) != 0;

	/*printk("fd_test_drive_present: ok=%d\n",ok); */
	/* force interrupt to abort restore operation (FDC1772 would try
	 * about 50 seconds!) */
	FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_FORCI);
	udelay(500);
	status = FDC1772_READ(FDC1772REG_STATUS);
	udelay(20);
	/*printk("fd_test_drive_present: just before OK code %d\n",ok); */

	if (ok) {
		/* dummy seek command to make WP bit accessible */
		FDC1772_WRITE(FDC1772REG_DATA, 0);
		FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_SEEK);
		printk("fd_test_drive_present: just before wait for int\n");
		/* DAG: Guess means wait for interrupt */
		while (!(ioc_readb(IOC_FIQSTAT) & 2));
		printk("fd_test_drive_present: just after wait for int\n");
		status = FDC1772_READ(FDC1772REG_STATUS);
	}
	printk("fd_test_drive_present: just before ENABLE_IRQ\n");
	ENABLE_IRQ();
	printk("fd_test_drive_present: about to return\n");
	return (ok);
}


/* Look how many and which kind of drives are connected. If there are
 * floppies, additionally start the disk-change and motor-off timers.
 */

static void config_types(void)
{
	int drive, cnt = 0;

	printk("Probing floppy drive(s):\n");
	for (drive = 0; drive < FD_MAX_UNITS; drive++) {
		fd_probe(drive);
		if (unit[drive].connected) {
			printk("fd%d\n", drive);
			++cnt;
		}
	}

	if (FDC1772_READ(FDC1772REG_STATUS) & FDC1772STAT_BUSY) {
		/* If FDC1772 is still busy from probing, give it another FORCI
		 * command to abort the operation. If this isn't done, the FDC1772
		 * will interrupt later and its IRQ line stays low, because
		 * the status register isn't read. And this will block any
		 * interrupts on this IRQ line :-(
		 */
		FDC1772_WRITE(FDC1772REG_CMD, FDC1772CMD_FORCI);
		udelay(500);
		FDC1772_READ(FDC1772REG_STATUS);
		udelay(20);
	}
	if (cnt > 0) {
		START_MOTOR_OFF_TIMER(FD_MOTOR_OFF_DELAY);
		if (cnt == 1)
			fd_select_drive(0);
		/*START_CHECK_CHANGE_TIMER( CHECK_CHANGE_DELAY ); */
	}
}

/*
 * floppy_open check for aliasing (/dev/fd0 can be the same as
 * /dev/PS0 etc), and disallows simultaneous access to the same
 * drive with different device numbers.
 */

static int floppy_open(struct inode *inode, struct file *filp)
{
	int drive = iminor(inode) & 3;
	int type =  iminor(inode) >> 2;
	int old_dev = fd_device[drive];

	if (fd_ref[drive] && old_dev != type)
		return -EBUSY;

	if (fd_ref[drive] == -1 || (fd_ref[drive] && filp->f_flags & O_EXCL))
		return -EBUSY;

	if (filp->f_flags & O_EXCL)
		fd_ref[drive] = -1;
	else
		fd_ref[drive]++;

	fd_device[drive] = type;

	if (filp->f_flags & O_NDELAY)
		return 0;

	if (filp->f_mode & 3) {
		check_disk_change(inode->i_bdev);
		if (filp->f_mode & 2) {
			if (unit[drive].wpstat) {
				floppy_release(inode, filp);
				return -EROFS;
			}
		}
	}
	return 0;
}


static int floppy_release(struct inode *inode, struct file *filp)
{
	int drive = iminor(inode) & 3;

	if (fd_ref[drive] < 0)
		fd_ref[drive] = 0;
	else if (!fd_ref[drive]--) {
		printk("floppy_release with fd_ref == 0");
		fd_ref[drive] = 0;
	}

	return 0;
}

static struct block_device_operations floppy_fops =
{
	.open		= floppy_open,
	.release	= floppy_release,
	.ioctl		= fd_ioctl,
	.media_changed	= check_floppy_change,
	.revalidate_disk= floppy_revalidate,
};

static struct kobject *floppy_find(dev_t dev, int *part, void *data)
{
	int drive = *part & 3;
	if ((*part >> 2) > NUM_DISK_TYPES || drive >= FD_MAX_UNITS)
		return NULL;
	*part = 0;
	return get_disk(disks[drive]);
}

int fd1772_init(void)
{
	static DEFINE_SPINLOCK(lock);
	int i, err = -ENOMEM;

	if (!machine_is_archimedes())
		return 0;

	for (i = 0; i < FD_MAX_UNITS; i++) {
		disks[i] = alloc_disk(1);
		if (!disks[i])
			goto err_disk;
	}

	err = register_blkdev(MAJOR_NR, "fd");
	if (err)
		goto err_disk;

	err = -EBUSY;
	if (request_dma(FLOPPY_DMA, "fd1772")) {
		printk("Unable to grab DMA%d for the floppy (1772) driver\n", FLOPPY_DMA);
		goto err_blkdev;
	};

	if (request_dma(FIQ_FD1772, "fd1772 end")) {
		printk("Unable to grab DMA%d for the floppy (1772) driver\n", FIQ_FD1772);
		goto err_dma1;
	};

	/* initialize variables */
	SelectedDrive = -1;
#ifdef TRACKBUFFER
	BufferDrive = BufferSide = BufferTrack = -1;
	/* Atari uses 512 - I want to eventually cope with 1K sectors */
	DMABuffer = kmalloc((FD1772_MAX_SECTORS+1)*512,GFP_KERNEL);
	TrackBuffer = DMABuffer + 512;
#else
	/* Allocate memory for the DMAbuffer - on the Atari this takes it
	   out of some special memory... */
	DMABuffer = kmalloc(2048);	/* Copes with pretty large sectors */
#endif
	err = -ENOMEM;
	if (!DMAbuffer)
		goto err_dma2;

	enable_dma(FIQ_FD1772);	/* This inserts a call to our command end routine */

	floppy_queue = blk_init_queue(do_fd_request, &lock);
	if (!floppy_queue)
		goto err_queue;

	for (i = 0; i < FD_MAX_UNITS; i++) {
		unit[i].track = -1;
		disks[i]->major = MAJOR_NR;
		disks[i]->first_minor = 0;
		disks[i]->fops = &floppy_fops;
		sprintf(disks[i]->disk_name, "fd%d", i);
		disks[i]->private_data = &unit[i];
		disks[i]->queue = floppy_queue;
		set_capacity(disks[i], MAX_DISK_SIZE * 2);
	}
	blk_register_region(MKDEV(MAJOR_NR, 0), 256, THIS_MODULE,
				floppy_find, NULL, NULL);

	for (i = 0; i < FD_MAX_UNITS; i++)
		add_disk(disks[i]);

	config_types();

	return 0;

 err_queue:
	kfree(DMAbuffer);
 err_dma2:
	free_dma(FIQ_FD1772);

 err_dma1:
	free_dma(FLOPPY_DMA);

 err_blkdev:
	unregister_blkdev(MAJOR_NR, "fd");

 err_disk:
	while (i--)
		put_disk(disks[i]);
	return err;
}