summaryrefslogtreecommitdiffstats
path: root/drivers/acorn/block/mfmhd.c
blob: 689a4c3542babc00e385699fe1caf4b02c0f9103 (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
/*
 * linux/drivers/acorn/block/mfmhd.c
 *
 * Copyright (C) 1995, 1996 Russell King, Dave Alan Gilbert (gilbertd@cs.man.ac.uk)
 *
 * MFM hard drive code [experimental]
 */

/*
 * Change list:
 *
 *  3/2/96:DAG: Started a change list :-)
 *              Set the hardsect_size pointers up since we are running 256 byte
 *                sectors
 *              Added DMA code, put it into the rw_intr
 *              Moved RCAL out of generic interrupt code - don't want to do it
 *                while DMA'ing - its now in individual handlers.
 *              Took interrupt handlers off task queue lists and called
 *                directly - not sure of implications.
 *
 * 18/2/96:DAG: Well its reading OK I think, well enough for image file code
 *              to find the image file; but now I've discovered that I actually
 *              have to put some code in for image files.
 *
 *              Added stuff for image files; seems to work, but I've not
 *              got a multisegment image file (I don't think!).
 *              Put in a hack (yep a real hack) for multiple cylinder reads.
 *              Not convinced its working.
 *
 *  5/4/96:DAG: Added asm/hardware.h and use IOC_ macros
 *              Rewrote dma code in mfm.S (again!) - now takes a word at a time
 *              from main RAM for speed; still doesn't feel speedy!
 *
 * 20/4/96:DAG: After rewriting mfm.S a heck of a lot of times and speeding
 *              things up, I've finally figured out why its so damn slow.
 *              Linux is only reading a block at a time, and so you never
 *              get more than 1K per disc revoloution ~=60K/second.
 *
 * 27/4/96:DAG: On Russell's advice I change ll_rw_blk.c to ask it to
 *              join adjacent blocks together. Everything falls flat on its
 *              face.
 *              Four hours of debugging later; I hadn't realised that
 *              ll_rw_blk would be so generous as to join blocks whose
 *              results aren't going into consecutive buffers.
 * 
 *              OK; severe rehacking of mfm_rw_interrupt; now end_request's
 *              as soon as its DMA'd each request.  Odd thing is that
 *              we are sometimes getting interrupts where we are not transferring
 *              any data; why? Is that what happens when you miss? I doubt
 *              it; are we too fast? No - its just at command ends. Got 240K/s
 *              better than before, but RiscOS hits 480K/s
 *
 * 25/6/96:RMK: Fixed init code to allow the MFM podule to work.  Increased the
 *              number of errors for my Miniscribe drive (8425).
 *
 * 30/6/96:DAG: Russell suggested that a check drive 0 might turn the LEDs off
 *              - so in request_done just before it clears Busy it sends a
 *              check drive 0 - and the LEDs go off!!!!
 *
 *              Added test for mainboard controller. - Removes need for separate
 *              define.
 *
 * 13/7/96:DAG: Changed hardware sectore size to 512 in attempt to make
 *              IM drivers work.
 * 21/7/96:DAG: Took out old image file stuff (accessing it now produces an IO
 *              error.)
 *
 * 17/8/96:DAG: Ran through indent -kr -i8; evil - all my nice 2 character indents
 *              gone :-( Hand modified afterwards.
 *		Took out last remains of the older image map system.
 *
 * 22/9/96:DAG:	Changed mfm.S so it will carry on DMA'ing til; BSY is dropped
 *		Changed mfm_rw_intr so that it doesn't follow the error
 *		code until BSY is dropped. Nope - still broke. Problem
 *		may revolve around when it reads the results for the error
 *		number?
 *
 *16/11/96:DAG:	Modified for 2.0.18; request_irq changed
 *
 *17/12/96:RMK: Various cleanups, reorganisation, and the changes for new IO system.
 *		Improved probe for onboard MFM chip - it was hanging on my A5k.
 *		Added autodetect CHS code such that we don't rely on the presence
 *		of an ADFS boot block.  Added ioport resource manager calls so
 *		that we don't clash with already-running hardware (eg. RiscPC Ether
 *		card slots if someone tries this)!
 *
 * 17/1/97:RMK:	Upgraded to 2.1 kernels.
 *
 *  4/3/98:RMK:	Changed major number to 21.
 *
 * 27/6/98:RMK:	Changed asm/delay.h to linux/delay.h for mdelay().
 */

/*
 * Possible enhancements:
 *  Multi-thread the code so that it is possible that while one drive
 *  is seeking, the other one can be reading data/seeking as well.
 *  This would be a performance boost with dual drive systems.
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/major.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/blkpg.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/ecard.h>
#include <asm/hardware/ioc.h>

static void (*do_mfm)(void) = NULL;
static struct request_queue *mfm_queue;
static DEFINE_SPINLOCK(mfm_lock);

#define MAJOR_NR	MFM_ACORN_MAJOR
#define QUEUE (mfm_queue)
#define CURRENT elv_next_request(mfm_queue)

/*
 * Configuration section
 *
 * This is the maximum number of drives that we accept
 */
#define MFM_MAXDRIVES 2
/*
 * Linux I/O address of onboard MFM controller or 0 to disable this
 */
#define ONBOARD_MFM_ADDRESS ((0x002d0000 >> 2) | 0x80000000)
/*
 * Uncomment this to enable debugging in the MFM driver...
 */
#ifndef DEBUG
/*#define DEBUG */
#endif
/*
 * End of configuration
 */

 
/*
 * This structure contains all information to do with a particular physical
 * device.
 */
struct mfm_info {
	unsigned char sectors;
	unsigned char heads;
	unsigned short cylinders;
	unsigned short lowcurrent;
	unsigned short precomp;
#define NO_TRACK -1
#define NEED_1_RECAL -2
#define NEED_2_RECAL -3
		 int cylinder;
	struct {
		char recal;
		char report;
		char abort;
	} errors;
} mfm_info[MFM_MAXDRIVES];

#define MFM_DRV_INFO mfm_info[raw_cmd.dev]

/* Stuff from the assembly routines */
extern unsigned int hdc63463_baseaddress;	/* Controller base address */
extern unsigned int hdc63463_irqpolladdress;	/* Address to read to test for int */
extern unsigned int hdc63463_irqpollmask;	/* Mask for irq register */
extern unsigned int hdc63463_dataptr;	/* Pointer to kernel data space to DMA */
extern int hdc63463_dataleft;	/* Number of bytes left to transfer */




static int lastspecifieddrive;
static unsigned Busy;

static unsigned int PartFragRead;	/* The number of sectors which have been read
					   during a partial read split over two
					   cylinders.  If 0 it means a partial
					   read did not occur. */

static unsigned int PartFragRead_RestartBlock;	/* Where to restart on a split access */
static unsigned int PartFragRead_SectorsLeft;	/* Where to restart on a split access */

static int Sectors256LeftInCurrent;	/* i.e. 256 byte sectors left in current */
static int SectorsLeftInRequest;	/* i.e. blocks left in the thing mfm_request was called for */
static int Copy_Sector;		/* The 256 byte sector we are currently at - fragments need to know 
				   where to take over */
static char *Copy_buffer;


static void mfm_seek(void);
static void mfm_rerequest(void);
static void mfm_request(void);
static void mfm_specify (void);
static void issue_request(unsigned int block, unsigned int nsect,
			  struct request *req);

static unsigned int mfm_addr;		/* Controller address */
static unsigned int mfm_IRQPollLoc;	/* Address to read for IRQ information */
static unsigned int mfm_irqenable;	/* Podule IRQ enable location */
static unsigned char mfm_irq;		/* Interrupt number */
static int mfm_drives = 0;		/* drives available */
static int mfm_status = 0;		/* interrupt status */
static int *errors;

static struct rawcmd {
	unsigned int dev;
	unsigned int cylinder;
	unsigned int head;
	unsigned int sector;
	unsigned int cmdtype;
	unsigned int cmdcode;
	unsigned char cmddata[16];
	unsigned int cmdlen;
} raw_cmd;

static unsigned char result[16];

static struct cont {
	void (*interrupt) (void);	/* interrupt handler */
	void (*error) (void);	/* error handler */
	void (*redo) (void);	/* redo handler */
	void (*done) (int st);	/* done handler */
} *cont = NULL;

#if 0
static struct tq_struct mfm_tq = {0, 0, (void (*)(void *)) NULL, 0};
#endif

int number_mfm_drives = 1;

/* ------------------------------------------------------------------------------------------ */
/*
 * From the HD63463 data sheet from Hitachi Ltd.
 */

#define MFM_COMMAND (mfm_addr + 0)
#define MFM_DATAOUT (mfm_addr + 1)
#define MFM_STATUS  (mfm_addr + 8)
#define MFM_DATAIN  (mfm_addr + 9)

#define CMD_ABT		0xF0	/* Abort */
#define CMD_SPC		0xE8	/* Specify */
#define CMD_TST		0xE0	/* Test */
#define CMD_RCLB	0xC8	/* Recalibrate */
#define CMD_SEK		0xC0	/* Seek */
#define CMD_WFS		0xAB	/* Write Format Skew */
#define CMD_WFM		0xA3	/* Write Format */
#define CMD_MTB		0x90	/* Memory to buffer */
#define CMD_CMPD	0x88	/* Compare data */
#define CMD_WD		0x87	/* Write data */
#define CMD_RED		0x70	/* Read erroneous data */
#define CMD_RIS		0x68	/* Read ID skew */
#define CMD_FID		0x61	/* Find ID */
#define CMD_RID		0x60	/* Read ID */
#define CMD_BTM		0x50	/* Buffer to memory */
#define CMD_CKD		0x48	/* Check data */
#define CMD_RD		0x40	/* Read data */
#define CMD_OPBW	0x38	/* Open buffer write */
#define CMD_OPBR	0x30	/* Open buffer read */
#define CMD_CKV		0x28	/* Check drive */
#define CMD_CKE		0x20	/* Check ECC */
#define CMD_POD		0x18	/* Polling disable */
#define CMD_POL		0x10	/* Polling enable */
#define CMD_RCAL	0x08	/* Recall */

#define STAT_BSY	0x8000	/* Busy */
#define STAT_CPR	0x4000	/* Command Parameter Rejection */
#define STAT_CED	0x2000	/* Command end */
#define STAT_SED	0x1000	/* Seek end */
#define STAT_DER	0x0800	/* Drive error */
#define STAT_ABN	0x0400	/* Abnormal end */
#define STAT_POL	0x0200	/* Polling */

/* ------------------------------------------------------------------------------------------ */
#ifdef DEBUG
static void console_printf(const char *fmt,...)
{
	static char buffer[2048];	/* Arbitary! */
	extern void console_print(const char *);
	unsigned long flags;
	va_list ap;

	local_irq_save(flags);

	va_start(ap, fmt);
	vsprintf(buffer, fmt, ap);
	console_print(buffer);
	va_end(fmt);

	local_irq_restore(flags);
};	/* console_printf */

#define DBG(x...) console_printf(x)
#else
#define DBG(x...)
#endif

static void print_status(void)
{
	char *error;
	static char *errors[] = {
         "no error",
	 "command aborted",
	 "invalid command",
	 "parameter error",
	 "not initialised",
	 "rejected TEST",
	 "no useld",
	 "write fault",
	 "not ready",
	 "no scp",
	 "in seek",
	 "invalid NCA",
	 "invalid step rate",
	 "seek error",
	 "over run",
	 "invalid PHA",
	 "data field EEC error",
	 "data field CRC error",
	 "error corrected",
	 "data field fatal error",
	 "no data am",
	 "not hit",
	 "ID field CRC error",
	 "time over",
	 "no ID am",
	 "not writable"
	};
	if (result[1] < 0x65)
		error = errors[result[1] >> 2];
	else
		error = "unknown";
	printk("(");
	if (mfm_status & STAT_BSY) printk("BSY ");
	if (mfm_status & STAT_CPR) printk("CPR ");
	if (mfm_status & STAT_CED) printk("CED ");
	if (mfm_status & STAT_SED) printk("SED ");
	if (mfm_status & STAT_DER) printk("DER ");
	if (mfm_status & STAT_ABN) printk("ABN ");
	if (mfm_status & STAT_POL) printk("POL ");
	printk(") SSB = %X (%s)\n", result[1], error);

}

/* ------------------------------------------------------------------------------------- */

static void issue_command(int command, unsigned char *cmdb, int len)
{
	int status;
#ifdef DEBUG
	int i;
	console_printf("issue_command: %02X: ", command);
	for (i = 0; i < len; i++)
		console_printf("%02X ", cmdb[i]);
	console_printf("\n");
#endif

	do {
		status = inw(MFM_STATUS);
	} while (status & (STAT_BSY | STAT_POL));
	DBG("issue_command: status after pol/bsy loop: %02X:\n ", status >> 8);

	if (status & (STAT_CPR | STAT_CED | STAT_SED | STAT_DER | STAT_ABN)) {
		outw(CMD_RCAL, MFM_COMMAND);
		while (inw(MFM_STATUS) & STAT_BSY);
	}
	status = inw(MFM_STATUS);
	DBG("issue_command: status before parameter issue: %02X:\n ", status >> 8);

	while (len > 0) {
		outw(cmdb[1] | (cmdb[0] << 8), MFM_DATAOUT);
		len -= 2;
		cmdb += 2;
	}
	status = inw(MFM_STATUS);
	DBG("issue_command: status before command issue: %02X:\n ", status >> 8);

	outw(command, MFM_COMMAND);
	status = inw(MFM_STATUS);
	DBG("issue_command: status immediately after command issue: %02X:\n ", status >> 8);
}

static void wait_for_completion(void)
{
	while ((mfm_status = inw(MFM_STATUS)) & STAT_BSY);
}

static void wait_for_command_end(void)
{
	int i;

	while (!((mfm_status = inw(MFM_STATUS)) & STAT_CED));

	for (i = 0; i < 16;) {
		int in;
		in = inw(MFM_DATAIN);
		result[i++] = in >> 8;
		result[i++] = in;
	}
	outw (CMD_RCAL, MFM_COMMAND);
}

/* ------------------------------------------------------------------------------------- */

static void mfm_rw_intr(void)
{
	int old_status;		/* Holds status on entry, we read to see if the command just finished */
#ifdef DEBUG
	console_printf("mfm_rw_intr...dataleft=%d\n", hdc63463_dataleft);
	print_status();
#endif

  /* Now don't handle the error until BSY drops */
	if ((mfm_status & (STAT_DER | STAT_ABN)) && ((mfm_status&STAT_BSY)==0)) {
		/* Something has gone wrong - let's try that again */
		outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
		if (cont) {
			DBG("mfm_rw_intr: DER/ABN err\n");
			cont->error();
			cont->redo();
		};
		return;
	};

	/* OK so what ever happened it's not an error, now I reckon we are left between
	   a choice of command end or some data which is ready to be collected */
	/* I think we have to transfer data while the interrupt line is on and its
	   not any other type of interrupt */
	if (CURRENT->cmd == WRITE) {
		extern void hdc63463_writedma(void);
		if ((hdc63463_dataleft <= 0) && (!(mfm_status & STAT_CED))) {
			printk("mfm_rw_intr: Apparent DMA write request when no more to DMA\n");
			if (cont) {
				cont->error();
				cont->redo();
			};
			return;
		};
		hdc63463_writedma();
	} else {
		extern void hdc63463_readdma(void);
		if ((hdc63463_dataleft <= 0) && (!(mfm_status & STAT_CED))) {
			printk("mfm_rw_intr: Apparent DMA read request when no more to DMA\n");
			if (cont) {
				cont->error();
				cont->redo();
			};
			return;
		};
		DBG("Going to try read dma..............status=0x%x, buffer=%p\n", mfm_status, hdc63463_dataptr);
		hdc63463_readdma();
	};			/* Read */

	if (hdc63463_dataptr != ((unsigned int) Copy_buffer + 256)) {
		/* If we didn't actually manage to get any data on this interrupt - but why? We got the interrupt */
		/* Ah - well looking at the status its just when we get command end; so no problem */
		/*console_printf("mfm: dataptr mismatch. dataptr=0x%08x Copy_buffer+256=0x%08p\n",
		   hdc63463_dataptr,Copy_buffer+256);
		   print_status(); */
	} else {
		Sectors256LeftInCurrent--;
		Copy_buffer += 256;
		Copy_Sector++;

		/* We have come to the end of this request */
		if (!Sectors256LeftInCurrent) {
			DBG("mfm: end_request for CURRENT=0x%p CURRENT(sector=%d current_nr_sectors=%d nr_sectors=%d)\n",
				       CURRENT, CURRENT->sector, CURRENT->current_nr_sectors, CURRENT->nr_sectors);

			CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
			CURRENT->sector += CURRENT->current_nr_sectors;
			SectorsLeftInRequest -= CURRENT->current_nr_sectors;

			end_request(CURRENT, 1);
			if (SectorsLeftInRequest) {
				hdc63463_dataptr = (unsigned int) CURRENT->buffer;
				Copy_buffer = CURRENT->buffer;
				Sectors256LeftInCurrent = CURRENT->current_nr_sectors * 2;
				errors = &(CURRENT->errors);
				/* These should match the present calculations of the next logical sector
				   on the device
				   Copy_Sector=CURRENT->sector*2; */

				if (Copy_Sector != CURRENT->sector * 2)
#ifdef DEBUG
					/*console_printf*/printk("mfm: Copy_Sector mismatch. Copy_Sector=%d CURRENT->sector*2=%d\n",
					Copy_Sector, CURRENT->sector * 2);
#else
					printk("mfm: Copy_Sector mismatch! Eek!\n");
#endif
			};	/* CURRENT */
		};	/* Sectors256LeftInCurrent */
	};

	old_status = mfm_status;
	mfm_status = inw(MFM_STATUS);
	if (mfm_status & (STAT_DER | STAT_ABN)) {
		/* Something has gone wrong - let's try that again */
		if (cont) {
			DBG("mfm_rw_intr: DER/ABN error\n");
			cont->error();
			cont->redo();
		};
		return;
	};

	/* If this code wasn't entered due to command_end but there is
	   now a command end we must read the command results out. If it was
	   entered like this then mfm_interrupt_handler would have done the
	   job. */
	if ((!((old_status & (STAT_CPR | STAT_BSY)) == STAT_CPR)) &&
	    ((mfm_status & (STAT_CPR | STAT_BSY)) == STAT_CPR)) {
		int len = 0;
		while (len < 16) {
			int in;
			in = inw(MFM_DATAIN);
			result[len++] = in >> 8;
			result[len++] = in;
		};
	};			/* Result read */

	/*console_printf ("mfm_rw_intr nearexit [%02X]\n", __raw_readb(mfm_IRQPollLoc)); */

	/* If end of command move on */
	if (mfm_status & (STAT_CED)) {
		outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
		/* End of command - trigger the next command */
		if (cont) {
			cont->done(1);
		}
		DBG("mfm_rw_intr: returned from cont->done\n");
	} else {
		/* Its going to generate another interrupt */
		do_mfm = mfm_rw_intr;
	};
}

static void mfm_setup_rw(void)
{
	DBG("setting up for rw...\n");

	do_mfm = mfm_rw_intr;
	issue_command(raw_cmd.cmdcode, raw_cmd.cmddata, raw_cmd.cmdlen);
}

static void mfm_recal_intr(void)
{
#ifdef DEBUG
	console_printf("recal intr - status = ");
	print_status();
#endif
	outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
	if (mfm_status & (STAT_DER | STAT_ABN)) {
		printk("recal failed\n");
		MFM_DRV_INFO.cylinder = NEED_2_RECAL;
		if (cont) {
			cont->error();
			cont->redo();
		}
		return;
	}
	/* Thats seek end - we are finished */
	if (mfm_status & STAT_SED) {
		issue_command(CMD_POD, NULL, 0);
		MFM_DRV_INFO.cylinder = 0;
		mfm_seek();
		return;
	}
	/* Command end without seek end (see data sheet p.20) for parallel seek
	   - we have to send a POL command to wait for the seek */
	if (mfm_status & STAT_CED) {
		do_mfm = mfm_recal_intr;
		issue_command(CMD_POL, NULL, 0);
		return;
	}
	printk("recal: unknown status\n");
}

static void mfm_seek_intr(void)
{
#ifdef DEBUG
	console_printf("seek intr - status = ");
	print_status();
#endif
	outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
	if (mfm_status & (STAT_DER | STAT_ABN)) {
		printk("seek failed\n");
		MFM_DRV_INFO.cylinder = NEED_2_RECAL;
		if (cont) {
			cont->error();
			cont->redo();
		}
		return;
	}
	if (mfm_status & STAT_SED) {
		issue_command(CMD_POD, NULL, 0);
		MFM_DRV_INFO.cylinder = raw_cmd.cylinder;
		mfm_seek();
		return;
	}
	if (mfm_status & STAT_CED) {
		do_mfm = mfm_seek_intr;
		issue_command(CMD_POL, NULL, 0);
		return;
	}
	printk("seek: unknown status\n");
}

/* IDEA2 seems to work better - its what RiscOS sets my
 * disc to - on its SECOND call to specify!
 */
#define IDEA2
#ifndef IDEA2
#define SPEC_SL 0x16
#define SPEC_SH 0xa9		/* Step pulse high=21, Record Length=001 (256 bytes) */
#else
#define SPEC_SL 0x00		/* OM2 - SL - step pulse low */
#define SPEC_SH 0x21		/* Step pulse high=4, Record Length=001 (256 bytes) */
#endif

static void mfm_setupspecify (int drive, unsigned char *cmdb)
{
	cmdb[0]  = 0x1f;		/* OM0 - !SECT,!MOD,!DIF,PADP,ECD,CRCP,CRCI,ACOR */
	cmdb[1]  = 0xc3;		/* OM1 - DTM,BRST,!CEDM,!SEDM,!DERM,0,AMEX,PSK */
	cmdb[2]  = SPEC_SL;		/* OM2 - SL - step pulse low */
	cmdb[3]  = (number_mfm_drives == 1) ? 0x02 : 0x06;	/* 1 or 2 drives */
	cmdb[4]  = 0xfc | ((mfm_info[drive].cylinders - 1) >> 8);/* RW time over/high part of number of cylinders */
	cmdb[5]  = mfm_info[drive].cylinders - 1;		/* low part of number of cylinders */
	cmdb[6]  = mfm_info[drive].heads - 1;			/* Number of heads */
	cmdb[7]  = mfm_info[drive].sectors - 1;			/* Number of sectors */
	cmdb[8]  = SPEC_SH;
	cmdb[9]  = 0x0a;		/* gap length 1 */
	cmdb[10] = 0x0d;		/* gap length 2 */
	cmdb[11] = 0x0c;		/* gap length 3 */
	cmdb[12] = (mfm_info[drive].precomp - 1) >> 8;	/* pre comp cylinder */
	cmdb[13] = mfm_info[drive].precomp - 1;
	cmdb[14] = (mfm_info[drive].lowcurrent - 1) >> 8;	/* Low current cylinder */
	cmdb[15] = mfm_info[drive].lowcurrent - 1;
}

static void mfm_specify (void)
{
	unsigned char cmdb[16];

	DBG("specify...dev=%d lastspecified=%d\n", raw_cmd.dev, lastspecifieddrive);
	mfm_setupspecify (raw_cmd.dev, cmdb);

	issue_command (CMD_SPC, cmdb, 16);
	/* Ensure that we will do another specify if we move to the other drive */
	lastspecifieddrive = raw_cmd.dev;
	wait_for_completion();
}

static void mfm_seek(void)
{
	unsigned char cmdb[4];

	DBG("seeking...\n");
	if (MFM_DRV_INFO.cylinder < 0) {
		do_mfm = mfm_recal_intr;
		DBG("mfm_seek: about to call specify\n");
		mfm_specify ();	/* DAG added this */

		cmdb[0] = raw_cmd.dev + 1;
		cmdb[1] = 0;

		issue_command(CMD_RCLB, cmdb, 2);
		return;
	}
	if (MFM_DRV_INFO.cylinder != raw_cmd.cylinder) {
		cmdb[0] = raw_cmd.dev + 1;
		cmdb[1] = 0;	/* raw_cmd.head; DAG: My data sheet says this should be 0 */
		cmdb[2] = raw_cmd.cylinder >> 8;
		cmdb[3] = raw_cmd.cylinder;

		do_mfm = mfm_seek_intr;
		issue_command(CMD_SEK, cmdb, 4);
	} else
		mfm_setup_rw();
}

static void mfm_initialise(void)
{
	DBG("init...\n");
	mfm_seek();
}

static void request_done(int uptodate)
{
	DBG("mfm:request_done\n");
	if (uptodate) {
		unsigned char block[2] = {0, 0};

		/* Apparently worked - let's check bytes left to DMA */
		if (hdc63463_dataleft != (PartFragRead_SectorsLeft * 256)) {
			printk("mfm: request_done - dataleft=%d - should be %d - Eek!\n", hdc63463_dataleft, PartFragRead_SectorsLeft * 256);
			end_request(CURRENT, 0);
			Busy = 0;
		};
		/* Potentially this means that we've done; but we might be doing
		   a partial access, (over two cylinders) or we may have a number
		   of fragments in an image file.  First let's deal with partial accesss
		 */
		if (PartFragRead) {
			/* Yep - a partial access */

			/* and issue the remainder */
			issue_request(PartFragRead_RestartBlock, PartFragRead_SectorsLeft, CURRENT);
			return;
		}

		/* ah well - perhaps there is another fragment to go */

		/* Increment pointers/counts to start of next fragment */
		if (SectorsLeftInRequest > 0) printk("mfm: SectorsLeftInRequest>0 - Eek! Shouldn't happen!\n");

		/* No - its the end of the line */
		/* end_request's should have happened at the end of sector DMAs */
		/* Turns Drive LEDs off - may slow it down? */
		if (!elv_next_request(QUEUE))
			issue_command(CMD_CKV, block, 2);

		Busy = 0;
		DBG("request_done: About to mfm_request\n");
		/* Next one please */
		mfm_request();	/* Moved from mfm_rw_intr */
		DBG("request_done: returned from mfm_request\n");
	} else {
		printk("mfm:request_done: update=0\n");
		end_request(CURRENT, 0);
		Busy = 0;
	}
}

static void error_handler(void)
{
	printk("error detected... status = ");
	print_status();
	(*errors)++;
	if (*errors > MFM_DRV_INFO.errors.abort)
		cont->done(0);
	if (*errors > MFM_DRV_INFO.errors.recal)
		MFM_DRV_INFO.cylinder = NEED_2_RECAL;
}

static void rw_interrupt(void)
{
	printk("rw_interrupt\n");
}

static struct cont rw_cont =
{
	rw_interrupt,
	error_handler,
	mfm_rerequest,
	request_done
};

/*
 * Actually gets round to issuing the request - note everything at this
 * point is in 256 byte sectors not Linux 512 byte blocks
 */
static void issue_request(unsigned int block, unsigned int nsect,
			  struct request *req)
{
	struct gendisk *disk = req->rq_disk;
	struct mfm_info *p = disk->private_data;
	int track, start_head, start_sector;
	int sectors_to_next_cyl;
	dev = p - mfm_info;

	track = block / p->sectors;
	start_sector = block % p->sectors;
	start_head = track % p->heads;

	/* First get the number of whole tracks which are free before the next
	   track */
	sectors_to_next_cyl = (p->heads - (start_head + 1)) * p->sectors;
	/* Then add in the number of sectors left on this track */
	sectors_to_next_cyl += (p->sectors - start_sector);

	DBG("issue_request: mfm_info[dev].sectors=%d track=%d\n", p->sectors, track);

	raw_cmd.dev = dev;
	raw_cmd.sector = start_sector;
	raw_cmd.head = start_head;
	raw_cmd.cylinder = track / p->heads;
	raw_cmd.cmdtype = CURRENT->cmd;
	raw_cmd.cmdcode = CURRENT->cmd == WRITE ? CMD_WD : CMD_RD;
	raw_cmd.cmddata[0] = dev + 1;	/* DAG: +1 to get US */
	raw_cmd.cmddata[1] = raw_cmd.head;
	raw_cmd.cmddata[2] = raw_cmd.cylinder >> 8;
	raw_cmd.cmddata[3] = raw_cmd.cylinder;
	raw_cmd.cmddata[4] = raw_cmd.head;
	raw_cmd.cmddata[5] = raw_cmd.sector;

	/* Was == and worked - how the heck??? */
	if (lastspecifieddrive != raw_cmd.dev)
		mfm_specify ();

	if (nsect <= sectors_to_next_cyl) {
		raw_cmd.cmddata[6] = nsect >> 8;
		raw_cmd.cmddata[7] = nsect;
		PartFragRead = 0;	/* All in one */
		PartFragRead_SectorsLeft = 0;	/* Must set this - used in DMA calcs */
	} else {
		raw_cmd.cmddata[6] = sectors_to_next_cyl >> 8;
		raw_cmd.cmddata[7] = sectors_to_next_cyl;
		PartFragRead = sectors_to_next_cyl;	/* only do this many this time */
		PartFragRead_RestartBlock = block + sectors_to_next_cyl;	/* Where to restart from */
		PartFragRead_SectorsLeft = nsect - sectors_to_next_cyl;
	}
	raw_cmd.cmdlen = 8;

	/* Setup DMA pointers */
	hdc63463_dataptr = (unsigned int) Copy_buffer;
	hdc63463_dataleft = nsect * 256;	/* Better way? */

	DBG("mfm%c: %sing: CHS=%d/%d/%d, sectors=%d, buffer=0x%08lx (%p)\n",
	     raw_cmd.dev + 'a', (CURRENT->cmd == READ) ? "read" : "writ",
		       raw_cmd.cylinder,
		       raw_cmd.head,
	    raw_cmd.sector, nsect, (unsigned long) Copy_buffer, CURRENT);

	cont = &rw_cont;
	errors = &(CURRENT->errors);
#if 0
	mfm_tq.routine = (void (*)(void *)) mfm_initialise;
	queue_task(&mfm_tq, &tq_immediate);
	mark_bh(IMMEDIATE_BH);
#else
	mfm_initialise();
#endif
}				/* issue_request */

/*
 * Called when an error has just happened - need to trick mfm_request
 * into thinking we weren't busy
 *
 * Turn off ints - mfm_request expects them this way
 */
static void mfm_rerequest(void)
{
	DBG("mfm_rerequest\n");
	cli();
	Busy = 0;
	mfm_request();
}

static struct gendisk *mfm_gendisk[2];

static void mfm_request(void)
{
	DBG("mfm_request CURRENT=%p Busy=%d\n", CURRENT, Busy);

	/* If we are still processing then return; we will get called again */
	if (Busy) {
		/* Again seems to be common in 1.3.45 */
		/*DBG*/printk("mfm_request: Exiting due to busy\n");
		return;
	}
	Busy = 1;

	while (1) {
		unsigned int block, nsect;
		struct gendisk *disk;

		DBG("mfm_request: loop start\n");
		sti();

		DBG("mfm_request: before !CURRENT\n");

		if (!CURRENT) {
			printk("mfm_request: Exiting due to empty queue (pre)\n");
			do_mfm = NULL;
			Busy = 0;
			return;
		}

		DBG("mfm_request:                 before arg extraction\n");

		disk = CURRENT->rq_disk;
		block = CURRENT->sector;
		nsect = CURRENT->nr_sectors;
		if (block >= get_capacity(disk) ||
		    block+nsect > get_capacity(disk)) {
			printk("%s: bad access: block=%d, count=%d, nr_sects=%ld\n",
			       disk->disk_name, block, nsect, get_capacity(disk));
			printk("mfm: continue 1\n");
			end_request(CURRENT, 0);
			Busy = 0;
			continue;
		}

		/* DAG: Linux doesn't cope with this - even though it has an array telling
		   it the hardware block size - silly */
		block <<= 1;	/* Now in 256 byte sectors */
		nsect <<= 1;	/* Ditto */

		SectorsLeftInRequest = nsect >> 1;
		Sectors256LeftInCurrent = CURRENT->current_nr_sectors * 2;
		Copy_buffer = CURRENT->buffer;
		Copy_Sector = CURRENT->sector << 1;

		DBG("mfm_request: block after offset=%d\n", block);

		if (CURRENT->cmd != READ && CURRENT->cmd != WRITE) {
			printk("unknown mfm-command %d\n", CURRENT->cmd);
			end_request(CURRENT, 0);
			Busy = 0;
			printk("mfm: continue 4\n");
			continue;
		}
		issue_request(block, nsect, CURRENT);

		break;
	}
	DBG("mfm_request: Dropping out bottom\n");
}

static void do_mfm_request(request_queue_t *q)
{
	DBG("do_mfm_request: about to mfm_request\n");
	mfm_request();
}

static void mfm_interrupt_handler(int unused, void *dev_id)
{
	void (*handler) (void) = do_mfm;

	do_mfm = NULL;

	DBG("mfm_interrupt_handler (handler=0x%p)\n", handler);

	mfm_status = inw(MFM_STATUS);

	/* If CPR (Command Parameter Reject) and not busy it means that the command
	   has some return message to give us */
	if ((mfm_status & (STAT_CPR | STAT_BSY)) == STAT_CPR) {
		int len = 0;
		while (len < 16) {
			int in;
			in = inw(MFM_DATAIN);
			result[len++] = in >> 8;
			result[len++] = in;
		}
	}
	if (handler) {
		handler();
		return;
	}
	outw (CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
	printk ("mfm: unexpected interrupt - status = ");
	print_status ();
	while (1);
}





/*
 * Tell the user about the drive if we decided it exists.
 */
static void mfm_geometry(int drive)
{
	struct mfm_info *p = mfm_info + drive;
	struct gendisk *disk = mfm_gendisk[drive];
	disk->private_data = p;
	if (p->cylinders)
		printk ("%s: %dMB CHS=%d/%d/%d LCC=%d RECOMP=%d\n",
			disk->disk_name,
			p->cylinders * p->heads * p->sectors / 4096,
			p->cylinders, p->heads, p->sectors,
			p->lowcurrent, p->precomp);
	set_capacity(disk, p->cylinders * p->heads * p->sectors / 2);
}

#ifdef CONFIG_BLK_DEV_MFM_AUTODETECT
/*
 * Attempt to detect a drive and find its geometry.  The drive has already been
 * specified...
 *
 * We first recalibrate the disk, then try to probe sectors, heads and then
 * cylinders.  NOTE! the cylinder probe may break drives.  The xd disk driver
 * does something along these lines, so I assume that most drives are up to
 * this mistreatment...
 */
static int mfm_detectdrive (int drive)
{
	unsigned int mingeo[3], maxgeo[3];
	unsigned int attribute, need_recal = 1;
	unsigned char cmdb[8];

	memset (mingeo, 0, sizeof (mingeo));
	maxgeo[0] = mfm_info[drive].sectors;
	maxgeo[1] = mfm_info[drive].heads;
	maxgeo[2] = mfm_info[drive].cylinders;

	cmdb[0] = drive + 1;
	cmdb[6] = 0;
	cmdb[7] = 1;
	for (attribute = 0; attribute < 3; attribute++) {
		while (mingeo[attribute] != maxgeo[attribute]) {
			unsigned int variable;

			variable = (maxgeo[attribute] + mingeo[attribute]) >> 1;
			cmdb[1] = cmdb[2] = cmdb[3] = cmdb[4] = cmdb[5] = 0;

			if (need_recal) {
				int tries = 5;

				do {
					issue_command (CMD_RCLB, cmdb, 2);
					wait_for_completion ();
					wait_for_command_end ();
					if  (result[1] == 0x20)
						break;
				} while (result[1] && --tries);
				if (result[1]) {
					outw (CMD_RCAL, MFM_COMMAND);
					return 0;
				}
				need_recal = 0;
			}

			switch (attribute) {
			case 0:
				cmdb[5] = variable;
				issue_command (CMD_CMPD, cmdb, 8);
				break;
			case 1:
				cmdb[1] = variable;
				cmdb[4] = variable;
				issue_command (CMD_CMPD, cmdb, 8);
				break;
			case 2:
				cmdb[2] = variable >> 8;
				cmdb[3] = variable;
				issue_command (CMD_SEK, cmdb, 4);
				break;
			}
			wait_for_completion ();
			wait_for_command_end ();

			switch (result[1]) {
			case 0x00:
			case 0x50:
				mingeo[attribute] = variable + 1;
				break;

			case 0x20:
				outw (CMD_RCAL, MFM_COMMAND);
				return 0;

			case 0x24:
				need_recal = 1;
			default:
				maxgeo[attribute] = variable;
				break;
			}
		}
	}
	mfm_info[drive].cylinders  = mingeo[2];
	mfm_info[drive].lowcurrent = mingeo[2];
	mfm_info[drive].precomp    = mingeo[2] / 2;
	mfm_info[drive].heads 	   = mingeo[1];
	mfm_info[drive].sectors	   = mingeo[0];
	outw (CMD_RCAL, MFM_COMMAND);
	return 1;
}
#endif

/*
 * Initialise all drive information for this controller.
 */
static int mfm_initdrives(void)
{
	int drive;

	if (number_mfm_drives > MFM_MAXDRIVES) {
		number_mfm_drives = MFM_MAXDRIVES;
		printk("No. of ADFS MFM drives is greater than MFM_MAXDRIVES - you can't have that many!\n");
	}

	for (drive = 0; drive < number_mfm_drives; drive++) {
		mfm_info[drive].lowcurrent = 1;
		mfm_info[drive].precomp    = 1;
		mfm_info[drive].cylinder   = -1;
		mfm_info[drive].errors.recal  = 0;
		mfm_info[drive].errors.report = 0;
		mfm_info[drive].errors.abort  = 4;

#ifdef CONFIG_BLK_DEV_MFM_AUTODETECT
		mfm_info[drive].cylinders  = 1024;
		mfm_info[drive].heads	   = 8;
		mfm_info[drive].sectors	   = 64;
		{
			unsigned char cmdb[16];

			mfm_setupspecify (drive, cmdb);
			cmdb[1] &= ~0x81;
			issue_command (CMD_SPC, cmdb, 16);
			wait_for_completion ();
			if (!mfm_detectdrive (drive)) {
				mfm_info[drive].cylinders = 0;
				mfm_info[drive].heads     = 0;
				mfm_info[drive].sectors   = 0;
			}
			cmdb[0] = cmdb[1] = 0;
			issue_command (CMD_CKV, cmdb, 2);
		}
#else
		mfm_info[drive].cylinders  = 1;	/* its going to have to figure it out from the partition info */
		mfm_info[drive].heads      = 4;
		mfm_info[drive].sectors    = 32;
#endif
	}
	return number_mfm_drives;
}



/*
 * The 'front' end of the mfm driver follows...
 */

static int mfm_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	struct mfm_info *p = bdev->bd_disk->private_data;

	geo->heads = p->heads;
	geo->sectors = p->sectors;
	geo->cylinders = p->cylinders;
	return 0;
}

/*
 * This is to handle various kernel command line parameters
 * specific to this driver.
 */
void mfm_setup(char *str, int *ints)
{
	return;
}

/*
 * Set the CHS from the ADFS boot block if it is present.  This is not ideal
 * since if there are any non-ADFS partitions on the disk, this won't work!
 * Hence, I want to get rid of this...
 */
void xd_set_geometry(struct block_device *bdev, unsigned char secsptrack,
			unsigned char heads, unsigned int secsize)
{
	struct mfm_info *p = bdev->bd_disk->private_data;
	int drive = p - mfm_info;
	unsigned long disksize = bdev->bd_inode->i_size;

	if (p->cylinders == 1) {
		p->sectors = secsptrack;
		p->heads = heads;
		p->cylinders = discsize / (secsptrack * heads * secsize);

		if ((heads < 1) || (p->cylinders > 1024)) {
			printk("%s: Insane disc shape! Setting to 512/4/32\n",
				bdev->bd_disk->disk_name);

			/* These values are fairly arbitary, but are there so that if your
			 * lucky you can pick apart your disc to find out what is going on -
			 * I reckon these figures won't hurt MOST drives
			 */
			p->sectors = 32;
			p->heads = 4;
			p->cylinders = 512;
		}
		if (raw_cmd.dev == drive)
			mfm_specify ();
		mfm_geometry (drive);
	}
}

static struct block_device_operations mfm_fops =
{
	.owner		= THIS_MODULE,
	.getgeo		= mfm_getgeo,
};

/*
 * See if there is a controller at the address presently at mfm_addr
 *
 * We check to see if the controller is busy - if it is, we abort it first,
 * and check that the chip is no longer busy after at least 180 clock cycles.
 * We then issue a command and check that the BSY or CPR bits are set.
 */
static int mfm_probecontroller (unsigned int mfm_addr)
{
	if (inw (MFM_STATUS) & STAT_BSY) {
		outw (CMD_ABT, MFM_COMMAND);
		udelay (50);
		if (inw (MFM_STATUS) & STAT_BSY)
			return 0;
	}

	if (inw (MFM_STATUS) & STAT_CED)
		outw (CMD_RCAL, MFM_COMMAND);

	outw (CMD_SEK, MFM_COMMAND);

	if (inw (MFM_STATUS) & (STAT_BSY | STAT_CPR)) {
		unsigned int count = 2000;
		while (inw (MFM_STATUS) & STAT_BSY) {
			udelay (500);
			if (!--count)
				return 0;
		}

		outw (CMD_RCAL, MFM_COMMAND);
	}
	return 1;
}

static int mfm_do_init(unsigned char irqmask)
{
	int i, ret;

	printk("mfm: found at address %08X, interrupt %d\n", mfm_addr, mfm_irq);

	ret = -EBUSY;
	if (!request_region (mfm_addr, 10, "mfm"))
		goto out1;

	ret = register_blkdev(MAJOR_NR, "mfm");
	if (ret)
		goto out2;

	/* Stuff for the assembler routines to get to */
	hdc63463_baseaddress	= ioaddr(mfm_addr);
	hdc63463_irqpolladdress	= mfm_IRQPollLoc;
	hdc63463_irqpollmask	= irqmask;

	mfm_queue = blk_init_queue(do_mfm_request, &mfm_lock);
	if (!mfm_queue)
		goto out2a;

	Busy = 0;
	lastspecifieddrive = -1;

	mfm_drives = mfm_initdrives();
	if (!mfm_drives) {
		ret = -ENODEV;
		goto out3;
	}
	
	for (i = 0; i < mfm_drives; i++) {
		struct gendisk *disk = alloc_disk(64);
		if (!disk)
			goto Enomem;
		disk->major = MAJOR_NR;
		disk->first_minor = i << 6;
		disk->fops = &mfm_fops;
		sprintf(disk->disk_name, "mfm%c", 'a'+i);
		mfm_gendisk[i] = disk;
	}

	printk("mfm: detected %d hard drive%s\n", mfm_drives,
				mfm_drives == 1 ? "" : "s");
	ret = request_irq(mfm_irq, mfm_interrupt_handler, IRQF_DISABLED, "MFM harddisk", NULL);
	if (ret) {
		printk("mfm: unable to get IRQ%d\n", mfm_irq);
		goto out4;
	}

	if (mfm_irqenable)
		outw(0x80, mfm_irqenable);	/* Required to enable IRQs from MFM podule */

	for (i = 0; i < mfm_drives; i++) {
		mfm_geometry(i);
		mfm_gendisk[i]->queue = mfm_queue;
		add_disk(mfm_gendisk[i]);
	}
	return 0;

out4:
	for (i = 0; i < mfm_drives; i++)
		put_disk(mfm_gendisk[i]);
out3:
	blk_cleanup_queue(mfm_queue);
out2a:
	unregister_blkdev(MAJOR_NR, "mfm");
out2:
	release_region(mfm_addr, 10);
out1:
	return ret;
Enomem:
	while (i--)
		put_disk(mfm_gendisk[i]);
	goto out3;
}

static void mfm_do_exit(void)
{
	int i;

	free_irq(mfm_irq, NULL);
	for (i = 0; i < mfm_drives; i++) {
		del_gendisk(mfm_gendisk[i]);
		put_disk(mfm_gendisk[i]);
	}
	blk_cleanup_queue(mfm_queue);
	unregister_blkdev(MAJOR_NR, "mfm");
	if (mfm_addr)
		release_region(mfm_addr, 10);
}

static int __devinit mfm_probe(struct expansion_card *ec, struct ecard_id *id)
{
	if (mfm_addr)
		return -EBUSY;

	mfm_addr	= ecard_address(ec, ECARD_IOC, ECARD_MEDIUM) + 0x800;
	mfm_IRQPollLoc	= ioaddr(mfm_addr + 0x400);
	mfm_irqenable	= mfm_IRQPollLoc;
	mfm_irq		= ec->irq;

	return mfm_do_init(0x08);
}

static void __devexit mfm_remove(struct expansion_card *ec)
{
	outw (0, mfm_irqenable);	/* Required to enable IRQs from MFM podule */
	mfm_do_exit();
}

static const struct ecard_id mfm_cids[] = {
	{ MANU_ACORN, PROD_ACORN_MFM },
	{ 0xffff, 0xffff },
};

static struct ecard_driver mfm_driver = {
	.probe		= mfm_probe,
	.remove		= __devexit(mfm_remove),
	.id_table	= mfm_cids,
	.drv = {
		.name	= "mfm",
	},
};

/*
 * Look for a MFM controller - first check the motherboard, then the podules
 * The podules have an extra interrupt enable that needs to be played with
 *
 * The HDC is accessed at MEDIUM IOC speeds.
 */
static int __init mfm_init (void)
{
	unsigned char irqmask;

	if (mfm_probecontroller(ONBOARD_MFM_ADDRESS)) {
		mfm_addr	= ONBOARD_MFM_ADDRESS;
		mfm_IRQPollLoc	= IOC_IRQSTATB;
		mfm_irqenable	= 0;
		mfm_irq		= IRQ_HARDDISK;
		return mfm_do_init(0x08);	/* IL3 pin */
	} else {
		return ecard_register_driver(&mfm_driver);
	}
}

static void __exit mfm_exit(void)
{
	if (mfm_addr == ONBOARD_MFM_ADDRESS)
		mfm_do_exit();
	else
		ecard_unregister_driver(&mfm_driver);
}

module_init(mfm_init)
module_exit(mfm_exit)
MODULE_LICENSE("GPL");