amiflop.c revision b5dc7840b3ebe9c7967dd8ba73db957767009ff9
1/*
2 *  linux/amiga/amiflop.c
3 *
4 *  Copyright (C) 1993  Greg Harp
5 *  Portions of this driver are based on code contributed by Brad Pepers
6 *
7 *  revised 28.5.95 by Joerg Dorchain
8 *  - now no bugs(?) any more for both HD & DD
9 *  - added support for 40 Track 5.25" drives, 80-track hopefully behaves
10 *    like 3.5" dd (no way to test - are there any 5.25" drives out there
11 *    that work on an A4000?)
12 *  - wrote formatting routine (maybe dirty, but works)
13 *
14 *  june/july 1995 added ms-dos support by Joerg Dorchain
15 *  (portions based on messydos.device and various contributors)
16 *  - currently only 9 and 18 sector disks
17 *
18 *  - fixed a bug with the internal trackbuffer when using multiple
19 *    disks the same time
20 *  - made formatting a bit safer
21 *  - added command line and machine based default for "silent" df0
22 *
23 *  december 1995 adapted for 1.2.13pl4 by Joerg Dorchain
24 *  - works but I think it's inefficient. (look in redo_fd_request)
25 *    But the changes were very efficient. (only three and a half lines)
26 *
27 *  january 1996 added special ioctl for tracking down read/write problems
28 *  - usage ioctl(d, RAW_TRACK, ptr); the raw track buffer (MFM-encoded data
29 *    is copied to area. (area should be large enough since no checking is
30 *    done - 30K is currently sufficient). return the actual size of the
31 *    trackbuffer
32 *  - replaced udelays() by a timer (CIAA timer B) for the waits
33 *    needed for the disk mechanic.
34 *
35 *  february 1996 fixed error recovery and multiple disk access
36 *  - both got broken the first time I tampered with the driver :-(
37 *  - still not safe, but better than before
38 *
39 *  revised Marts 3rd, 1996 by Jes Sorensen for use in the 1.3.28 kernel.
40 *  - Minor changes to accept the kdev_t.
41 *  - Replaced some more udelays with ms_delays. Udelay is just a loop,
42 *    and so the delay will be different depending on the given
43 *    processor :-(
44 *  - The driver could use a major cleanup because of the new
45 *    major/minor handling that came with kdev_t. It seems to work for
46 *    the time being, but I can't guarantee that it will stay like
47 *    that when we start using 16 (24?) bit minors.
48 *
49 * restructured jan 1997 by Joerg Dorchain
50 * - Fixed Bug accessing multiple disks
51 * - some code cleanup
52 * - added trackbuffer for each drive to speed things up
53 * - fixed some race conditions (who finds the next may send it to me ;-)
54 */
55
56#include <linux/module.h>
57
58#include <linux/fd.h>
59#include <linux/hdreg.h>
60#include <linux/delay.h>
61#include <linux/init.h>
62#include <linux/amifdreg.h>
63#include <linux/amifd.h>
64#include <linux/buffer_head.h>
65#include <linux/blkdev.h>
66#include <linux/elevator.h>
67#include <linux/interrupt.h>
68
69#include <asm/setup.h>
70#include <asm/uaccess.h>
71#include <asm/amigahw.h>
72#include <asm/amigaints.h>
73#include <asm/irq.h>
74
75#undef DEBUG /* print _LOTS_ of infos */
76
77#define RAW_IOCTL
78#ifdef RAW_IOCTL
79#define IOCTL_RAW_TRACK 0x5254524B  /* 'RTRK' */
80#endif
81
82/*
83 *  Defines
84 */
85
86/*
87 *  Error codes
88 */
89#define FD_OK		0	/* operation succeeded */
90#define FD_ERROR	-1	/* general error (seek, read, write, etc) */
91#define FD_NOUNIT	1	/* unit does not exist */
92#define FD_UNITBUSY	2	/* unit already active */
93#define FD_NOTACTIVE	3	/* unit is not active */
94#define FD_NOTREADY	4	/* unit is not ready (motor not on/no disk) */
95
96#define MFM_NOSYNC	1
97#define MFM_HEADER	2
98#define MFM_DATA	3
99#define MFM_TRACK	4
100
101/*
102 *  Floppy ID values
103 */
104#define FD_NODRIVE	0x00000000  /* response when no unit is present */
105#define FD_DD_3 	0xffffffff  /* double-density 3.5" (880K) drive */
106#define FD_HD_3 	0x55555555  /* high-density 3.5" (1760K) drive */
107#define FD_DD_5 	0xaaaaaaaa  /* double-density 5.25" (440K) drive */
108
109static unsigned long int fd_def_df0 = FD_DD_3;     /* default for df0 if it doesn't identify */
110
111module_param(fd_def_df0, ulong, 0);
112MODULE_LICENSE("GPL");
113
114static struct request_queue *floppy_queue;
115#define QUEUE (floppy_queue)
116#define CURRENT elv_next_request(floppy_queue)
117
118/*
119 *  Macros
120 */
121#define MOTOR_ON	(ciab.prb &= ~DSKMOTOR)
122#define MOTOR_OFF	(ciab.prb |= DSKMOTOR)
123#define SELECT(mask)    (ciab.prb &= ~mask)
124#define DESELECT(mask)  (ciab.prb |= mask)
125#define SELMASK(drive)  (1 << (3 + (drive & 3)))
126
127static struct fd_drive_type drive_types[] = {
128/*  code	name	   tr he   rdsz   wrsz sm pc1 pc2 sd  st st*/
129/*  warning: times are now in milliseconds (ms)                    */
130{ FD_DD_3,	"DD 3.5",  80, 2, 14716, 13630, 1, 80,161, 3, 18, 1},
131{ FD_HD_3,	"HD 3.5",  80, 2, 28344, 27258, 2, 80,161, 3, 18, 1},
132{ FD_DD_5,	"DD 5.25", 40, 2, 14716, 13630, 1, 40, 81, 6, 30, 2},
133{ FD_NODRIVE, "No Drive", 0, 0,     0,     0, 0,  0,  0,  0,  0, 0}
134};
135static int num_dr_types = ARRAY_SIZE(drive_types);
136
137static int amiga_read(int), dos_read(int);
138static void amiga_write(int), dos_write(int);
139static struct fd_data_type data_types[] = {
140	{ "Amiga", 11 , amiga_read, amiga_write},
141	{ "MS-Dos", 9, dos_read, dos_write}
142};
143
144/* current info on each unit */
145static struct amiga_floppy_struct unit[FD_MAX_UNITS];
146
147static struct timer_list flush_track_timer[FD_MAX_UNITS];
148static struct timer_list post_write_timer;
149static struct timer_list motor_on_timer;
150static struct timer_list motor_off_timer[FD_MAX_UNITS];
151static int on_attempts;
152
153/* Synchronization of FDC access */
154/* request loop (trackbuffer) */
155static volatile int fdc_busy = -1;
156static volatile int fdc_nested;
157static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
158
159static DECLARE_WAIT_QUEUE_HEAD(motor_wait);
160
161static volatile int selected = -1;	/* currently selected drive */
162
163static int writepending;
164static int writefromint;
165static char *raw_buf;
166
167static DEFINE_SPINLOCK(amiflop_lock);
168
169#define RAW_BUF_SIZE 30000  /* size of raw disk data */
170
171/*
172 * These are global variables, as that's the easiest way to give
173 * information to interrupts. They are the data used for the current
174 * request.
175 */
176static volatile char block_flag;
177static DECLARE_WAIT_QUEUE_HEAD(wait_fd_block);
178
179/* MS-Dos MFM Coding tables (should go quick and easy) */
180static unsigned char mfmencode[16]={
181	0x2a, 0x29, 0x24, 0x25, 0x12, 0x11, 0x14, 0x15,
182	0x4a, 0x49, 0x44, 0x45, 0x52, 0x51, 0x54, 0x55
183};
184static unsigned char mfmdecode[128];
185
186/* floppy internal millisecond timer stuff */
187static volatile int ms_busy = -1;
188static DECLARE_WAIT_QUEUE_HEAD(ms_wait);
189#define MS_TICKS ((amiga_eclock+50)/1000)
190
191/*
192 * Note that MAX_ERRORS=X doesn't imply that we retry every bad read
193 * max X times - some types of errors increase the errorcount by 2 or
194 * even 3, so we might actually retry only X/2 times before giving up.
195 */
196#define MAX_ERRORS 12
197
198#define custom amiga_custom
199
200/* Prevent "aliased" accesses. */
201static int fd_ref[4] = { 0,0,0,0 };
202static int fd_device[4] = { 0, 0, 0, 0 };
203
204/*
205 * Here come the actual hardware access and helper functions.
206 * They are not reentrant and single threaded because all drives
207 * share the same hardware and the same trackbuffer.
208 */
209
210/* Milliseconds timer */
211
212static irqreturn_t ms_isr(int irq, void *dummy, struct pt_regs *fp)
213{
214	ms_busy = -1;
215	wake_up(&ms_wait);
216	return IRQ_HANDLED;
217}
218
219/* all waits are queued up
220   A more generic routine would do a schedule a la timer.device */
221static void ms_delay(int ms)
222{
223	unsigned long flags;
224	int ticks;
225	if (ms > 0) {
226		local_irq_save(flags);
227		while (ms_busy == 0)
228			sleep_on(&ms_wait);
229		ms_busy = 0;
230		local_irq_restore(flags);
231		ticks = MS_TICKS*ms-1;
232		ciaa.tblo=ticks%256;
233		ciaa.tbhi=ticks/256;
234		ciaa.crb=0x19; /*count eclock, force load, one-shoot, start */
235		sleep_on(&ms_wait);
236	}
237}
238
239/* Hardware semaphore */
240
241/* returns true when we would get the semaphore */
242static inline int try_fdc(int drive)
243{
244	drive &= 3;
245	return ((fdc_busy < 0) || (fdc_busy == drive));
246}
247
248static void get_fdc(int drive)
249{
250	unsigned long flags;
251
252	drive &= 3;
253#ifdef DEBUG
254	printk("get_fdc: drive %d  fdc_busy %d  fdc_nested %d\n",drive,fdc_busy,fdc_nested);
255#endif
256	local_irq_save(flags);
257	while (!try_fdc(drive))
258		sleep_on(&fdc_wait);
259	fdc_busy = drive;
260	fdc_nested++;
261	local_irq_restore(flags);
262}
263
264static inline void rel_fdc(void)
265{
266#ifdef DEBUG
267	if (fdc_nested == 0)
268		printk("fd: unmatched rel_fdc\n");
269	printk("rel_fdc: fdc_busy %d fdc_nested %d\n",fdc_busy,fdc_nested);
270#endif
271	fdc_nested--;
272	if (fdc_nested == 0) {
273		fdc_busy = -1;
274		wake_up(&fdc_wait);
275	}
276}
277
278static void fd_select (int drive)
279{
280	unsigned char prb = ~0;
281
282	drive&=3;
283#ifdef DEBUG
284	printk("selecting %d\n",drive);
285#endif
286	if (drive == selected)
287		return;
288	get_fdc(drive);
289	selected = drive;
290
291	if (unit[drive].track % 2 != 0)
292		prb &= ~DSKSIDE;
293	if (unit[drive].motor == 1)
294		prb &= ~DSKMOTOR;
295	ciab.prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
296	ciab.prb = prb;
297	prb &= ~SELMASK(drive);
298	ciab.prb = prb;
299	rel_fdc();
300}
301
302static void fd_deselect (int drive)
303{
304	unsigned char prb;
305	unsigned long flags;
306
307	drive&=3;
308#ifdef DEBUG
309	printk("deselecting %d\n",drive);
310#endif
311	if (drive != selected) {
312		printk(KERN_WARNING "Deselecting drive %d while %d was selected!\n",drive,selected);
313		return;
314	}
315
316	get_fdc(drive);
317	local_irq_save(flags);
318
319	selected = -1;
320
321	prb = ciab.prb;
322	prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
323	ciab.prb = prb;
324
325	local_irq_restore (flags);
326	rel_fdc();
327
328}
329
330static void motor_on_callback(unsigned long nr)
331{
332	if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
333		wake_up (&motor_wait);
334	} else {
335		motor_on_timer.expires = jiffies + HZ/10;
336		add_timer(&motor_on_timer);
337	}
338}
339
340static int fd_motor_on(int nr)
341{
342	nr &= 3;
343
344	del_timer(motor_off_timer + nr);
345
346	if (!unit[nr].motor) {
347		unit[nr].motor = 1;
348		fd_select(nr);
349
350		motor_on_timer.data = nr;
351		mod_timer(&motor_on_timer, jiffies + HZ/2);
352
353		on_attempts = 10;
354		sleep_on (&motor_wait);
355		fd_deselect(nr);
356	}
357
358	if (on_attempts == 0) {
359		on_attempts = -1;
360#if 0
361		printk (KERN_ERR "motor_on failed, turning motor off\n");
362		fd_motor_off (nr);
363		return 0;
364#else
365		printk (KERN_WARNING "DSKRDY not set after 1.5 seconds - assuming drive is spinning notwithstanding\n");
366#endif
367	}
368
369	return 1;
370}
371
372static void fd_motor_off(unsigned long drive)
373{
374	long calledfromint;
375#ifdef MODULE
376	long decusecount;
377
378	decusecount = drive & 0x40000000;
379#endif
380	calledfromint = drive & 0x80000000;
381	drive&=3;
382	if (calledfromint && !try_fdc(drive)) {
383		/* We would be blocked in an interrupt, so try again later */
384		motor_off_timer[drive].expires = jiffies + 1;
385		add_timer(motor_off_timer + drive);
386		return;
387	}
388	unit[drive].motor = 0;
389	fd_select(drive);
390	udelay (1);
391	fd_deselect(drive);
392}
393
394static void floppy_off (unsigned int nr)
395{
396	int drive;
397
398	drive = nr & 3;
399	/* called this way it is always from interrupt */
400	motor_off_timer[drive].data = nr | 0x80000000;
401	mod_timer(motor_off_timer + drive, jiffies + 3*HZ);
402}
403
404static int fd_calibrate(int drive)
405{
406	unsigned char prb;
407	int n;
408
409	drive &= 3;
410	get_fdc(drive);
411	if (!fd_motor_on (drive))
412		return 0;
413	fd_select (drive);
414	prb = ciab.prb;
415	prb |= DSKSIDE;
416	prb &= ~DSKDIREC;
417	ciab.prb = prb;
418	for (n = unit[drive].type->tracks/2; n != 0; --n) {
419		if (ciaa.pra & DSKTRACK0)
420			break;
421		prb &= ~DSKSTEP;
422		ciab.prb = prb;
423		prb |= DSKSTEP;
424		udelay (2);
425		ciab.prb = prb;
426		ms_delay(unit[drive].type->step_delay);
427	}
428	ms_delay (unit[drive].type->settle_time);
429	prb |= DSKDIREC;
430	n = unit[drive].type->tracks + 20;
431	for (;;) {
432		prb &= ~DSKSTEP;
433		ciab.prb = prb;
434		prb |= DSKSTEP;
435		udelay (2);
436		ciab.prb = prb;
437		ms_delay(unit[drive].type->step_delay + 1);
438		if ((ciaa.pra & DSKTRACK0) == 0)
439			break;
440		if (--n == 0) {
441			printk (KERN_ERR "fd%d: calibrate failed, turning motor off\n", drive);
442			fd_motor_off (drive);
443			unit[drive].track = -1;
444			rel_fdc();
445			return 0;
446		}
447	}
448	unit[drive].track = 0;
449	ms_delay(unit[drive].type->settle_time);
450
451	rel_fdc();
452	fd_deselect(drive);
453	return 1;
454}
455
456static int fd_seek(int drive, int track)
457{
458	unsigned char prb;
459	int cnt;
460
461#ifdef DEBUG
462	printk("seeking drive %d to track %d\n",drive,track);
463#endif
464	drive &= 3;
465	get_fdc(drive);
466	if (unit[drive].track == track) {
467		rel_fdc();
468		return 1;
469	}
470	if (!fd_motor_on(drive)) {
471		rel_fdc();
472		return 0;
473	}
474	if (unit[drive].track < 0 && !fd_calibrate(drive)) {
475		rel_fdc();
476		return 0;
477	}
478
479	fd_select (drive);
480	cnt = unit[drive].track/2 - track/2;
481	prb = ciab.prb;
482	prb |= DSKSIDE | DSKDIREC;
483	if (track % 2 != 0)
484		prb &= ~DSKSIDE;
485	if (cnt < 0) {
486		cnt = - cnt;
487		prb &= ~DSKDIREC;
488	}
489	ciab.prb = prb;
490	if (track % 2 != unit[drive].track % 2)
491		ms_delay (unit[drive].type->side_time);
492	unit[drive].track = track;
493	if (cnt == 0) {
494		rel_fdc();
495		fd_deselect(drive);
496		return 1;
497	}
498	do {
499		prb &= ~DSKSTEP;
500		ciab.prb = prb;
501		prb |= DSKSTEP;
502		udelay (1);
503		ciab.prb = prb;
504		ms_delay (unit[drive].type->step_delay);
505	} while (--cnt != 0);
506	ms_delay (unit[drive].type->settle_time);
507
508	rel_fdc();
509	fd_deselect(drive);
510	return 1;
511}
512
513static unsigned long fd_get_drive_id(int drive)
514{
515	int i;
516	ulong id = 0;
517
518  	drive&=3;
519  	get_fdc(drive);
520	/* set up for ID */
521	MOTOR_ON;
522	udelay(2);
523	SELECT(SELMASK(drive));
524	udelay(2);
525	DESELECT(SELMASK(drive));
526	udelay(2);
527	MOTOR_OFF;
528	udelay(2);
529	SELECT(SELMASK(drive));
530	udelay(2);
531	DESELECT(SELMASK(drive));
532	udelay(2);
533
534	/* loop and read disk ID */
535	for (i=0; i<32; i++) {
536		SELECT(SELMASK(drive));
537		udelay(2);
538
539		/* read and store value of DSKRDY */
540		id <<= 1;
541		id |= (ciaa.pra & DSKRDY) ? 0 : 1;	/* cia regs are low-active! */
542
543		DESELECT(SELMASK(drive));
544	}
545
546	rel_fdc();
547
548        /*
549         * RB: At least A500/A2000's df0: don't identify themselves.
550         * As every (real) Amiga has at least a 3.5" DD drive as df0:
551         * we default to that if df0: doesn't identify as a certain
552         * type.
553         */
554        if(drive == 0 && id == FD_NODRIVE)
555	{
556                id = fd_def_df0;
557                printk(KERN_NOTICE "fd: drive 0 didn't identify, setting default %08lx\n", (ulong)fd_def_df0);
558	}
559	/* return the ID value */
560	return (id);
561}
562
563static irqreturn_t fd_block_done(int irq, void *dummy, struct pt_regs *fp)
564{
565	if (block_flag)
566		custom.dsklen = 0x4000;
567
568	if (block_flag == 2) { /* writing */
569		writepending = 2;
570		post_write_timer.expires = jiffies + 1; /* at least 2 ms */
571		post_write_timer.data = selected;
572		add_timer(&post_write_timer);
573	}
574	else {                /* reading */
575		block_flag = 0;
576		wake_up (&wait_fd_block);
577	}
578	return IRQ_HANDLED;
579}
580
581static void raw_read(int drive)
582{
583	drive&=3;
584	get_fdc(drive);
585	while (block_flag)
586		sleep_on(&wait_fd_block);
587	fd_select(drive);
588	/* setup adkcon bits correctly */
589	custom.adkcon = ADK_MSBSYNC;
590	custom.adkcon = ADK_SETCLR|ADK_WORDSYNC|ADK_FAST;
591
592	custom.dsksync = MFM_SYNC;
593
594	custom.dsklen = 0;
595	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
596	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
597	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
598
599	block_flag = 1;
600
601	while (block_flag)
602		sleep_on (&wait_fd_block);
603
604	custom.dsklen = 0;
605	fd_deselect(drive);
606	rel_fdc();
607}
608
609static int raw_write(int drive)
610{
611	ushort adk;
612
613	drive&=3;
614	get_fdc(drive); /* corresponds to rel_fdc() in post_write() */
615	if ((ciaa.pra & DSKPROT) == 0) {
616		rel_fdc();
617		return 0;
618	}
619	while (block_flag)
620		sleep_on(&wait_fd_block);
621	fd_select(drive);
622	/* clear adkcon bits */
623	custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
624	/* set appropriate adkcon bits */
625	adk = ADK_SETCLR|ADK_FAST;
626	if ((ulong)unit[drive].track >= unit[drive].type->precomp2)
627		adk |= ADK_PRECOMP1;
628	else if ((ulong)unit[drive].track >= unit[drive].type->precomp1)
629		adk |= ADK_PRECOMP0;
630	custom.adkcon = adk;
631
632	custom.dsklen = DSKLEN_WRITE;
633	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
634	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
635	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
636
637	block_flag = 2;
638	return 1;
639}
640
641/*
642 * to be called at least 2ms after the write has finished but before any
643 * other access to the hardware.
644 */
645static void post_write (unsigned long drive)
646{
647#ifdef DEBUG
648	printk("post_write for drive %ld\n",drive);
649#endif
650	drive &= 3;
651	custom.dsklen = 0;
652	block_flag = 0;
653	writepending = 0;
654	writefromint = 0;
655	unit[drive].dirty = 0;
656	wake_up(&wait_fd_block);
657	fd_deselect(drive);
658	rel_fdc(); /* corresponds to get_fdc() in raw_write */
659}
660
661
662/*
663 * The following functions are to convert the block contents into raw data
664 * written to disk and vice versa.
665 * (Add other formats here ;-))
666 */
667
668static unsigned long scan_sync(unsigned long raw, unsigned long end)
669{
670	ushort *ptr = (ushort *)raw, *endp = (ushort *)end;
671
672	while (ptr < endp && *ptr++ != 0x4489)
673		;
674	if (ptr < endp) {
675		while (*ptr == 0x4489 && ptr < endp)
676			ptr++;
677		return (ulong)ptr;
678	}
679	return 0;
680}
681
682static inline unsigned long checksum(unsigned long *addr, int len)
683{
684	unsigned long csum = 0;
685
686	len /= sizeof(*addr);
687	while (len-- > 0)
688		csum ^= *addr++;
689	csum = ((csum>>1) & 0x55555555)  ^  (csum & 0x55555555);
690
691	return csum;
692}
693
694static unsigned long decode (unsigned long *data, unsigned long *raw,
695			     int len)
696{
697	ulong *odd, *even;
698
699	/* convert length from bytes to longwords */
700	len >>= 2;
701	odd = raw;
702	even = odd + len;
703
704	/* prepare return pointer */
705	raw += len * 2;
706
707	do {
708		*data++ = ((*odd++ & 0x55555555) << 1) | (*even++ & 0x55555555);
709	} while (--len != 0);
710
711	return (ulong)raw;
712}
713
714struct header {
715	unsigned char magic;
716	unsigned char track;
717	unsigned char sect;
718	unsigned char ord;
719	unsigned char labels[16];
720	unsigned long hdrchk;
721	unsigned long datachk;
722};
723
724static int amiga_read(int drive)
725{
726	unsigned long raw;
727	unsigned long end;
728	int scnt;
729	unsigned long csum;
730	struct header hdr;
731
732	drive&=3;
733	raw = (long) raw_buf;
734	end = raw + unit[drive].type->read_size;
735
736	for (scnt = 0;scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
737		if (!(raw = scan_sync(raw, end))) {
738			printk (KERN_INFO "can't find sync for sector %d\n", scnt);
739			return MFM_NOSYNC;
740		}
741
742		raw = decode ((ulong *)&hdr.magic, (ulong *)raw, 4);
743		raw = decode ((ulong *)&hdr.labels, (ulong *)raw, 16);
744		raw = decode ((ulong *)&hdr.hdrchk, (ulong *)raw, 4);
745		raw = decode ((ulong *)&hdr.datachk, (ulong *)raw, 4);
746		csum = checksum((ulong *)&hdr,
747				(char *)&hdr.hdrchk-(char *)&hdr);
748
749#ifdef DEBUG
750		printk ("(%x,%d,%d,%d) (%lx,%lx,%lx,%lx) %lx %lx\n",
751			hdr.magic, hdr.track, hdr.sect, hdr.ord,
752			*(ulong *)&hdr.labels[0], *(ulong *)&hdr.labels[4],
753			*(ulong *)&hdr.labels[8], *(ulong *)&hdr.labels[12],
754			hdr.hdrchk, hdr.datachk);
755#endif
756
757		if (hdr.hdrchk != csum) {
758			printk(KERN_INFO "MFM_HEADER: %08lx,%08lx\n", hdr.hdrchk, csum);
759			return MFM_HEADER;
760		}
761
762		/* verify track */
763		if (hdr.track != unit[drive].track) {
764			printk(KERN_INFO "MFM_TRACK: %d, %d\n", hdr.track, unit[drive].track);
765			return MFM_TRACK;
766		}
767
768		raw = decode ((ulong *)(unit[drive].trackbuf + hdr.sect*512),
769			      (ulong *)raw, 512);
770		csum = checksum((ulong *)(unit[drive].trackbuf + hdr.sect*512), 512);
771
772		if (hdr.datachk != csum) {
773			printk(KERN_INFO "MFM_DATA: (%x:%d:%d:%d) sc=%d %lx, %lx\n",
774			       hdr.magic, hdr.track, hdr.sect, hdr.ord, scnt,
775			       hdr.datachk, csum);
776			printk (KERN_INFO "data=(%lx,%lx,%lx,%lx)\n",
777				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[0],
778				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[1],
779				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[2],
780				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[3]);
781			return MFM_DATA;
782		}
783	}
784
785	return 0;
786}
787
788static void encode(unsigned long data, unsigned long *dest)
789{
790	unsigned long data2;
791
792	data &= 0x55555555;
793	data2 = data ^ 0x55555555;
794	data |= ((data2 >> 1) | 0x80000000) & (data2 << 1);
795
796	if (*(dest - 1) & 0x00000001)
797		data &= 0x7FFFFFFF;
798
799	*dest = data;
800}
801
802static void encode_block(unsigned long *dest, unsigned long *src, int len)
803{
804	int cnt, to_cnt = 0;
805	unsigned long data;
806
807	/* odd bits */
808	for (cnt = 0; cnt < len / 4; cnt++) {
809		data = src[cnt] >> 1;
810		encode(data, dest + to_cnt++);
811	}
812
813	/* even bits */
814	for (cnt = 0; cnt < len / 4; cnt++) {
815		data = src[cnt];
816		encode(data, dest + to_cnt++);
817	}
818}
819
820static unsigned long *putsec(int disk, unsigned long *raw, int cnt)
821{
822	struct header hdr;
823	int i;
824
825	disk&=3;
826	*raw = (raw[-1]&1) ? 0x2AAAAAAA : 0xAAAAAAAA;
827	raw++;
828	*raw++ = 0x44894489;
829
830	hdr.magic = 0xFF;
831	hdr.track = unit[disk].track;
832	hdr.sect = cnt;
833	hdr.ord = unit[disk].dtype->sects * unit[disk].type->sect_mult - cnt;
834	for (i = 0; i < 16; i++)
835		hdr.labels[i] = 0;
836	hdr.hdrchk = checksum((ulong *)&hdr,
837			      (char *)&hdr.hdrchk-(char *)&hdr);
838	hdr.datachk = checksum((ulong *)(unit[disk].trackbuf+cnt*512), 512);
839
840	encode_block(raw, (ulong *)&hdr.magic, 4);
841	raw += 2;
842	encode_block(raw, (ulong *)&hdr.labels, 16);
843	raw += 8;
844	encode_block(raw, (ulong *)&hdr.hdrchk, 4);
845	raw += 2;
846	encode_block(raw, (ulong *)&hdr.datachk, 4);
847	raw += 2;
848	encode_block(raw, (ulong *)(unit[disk].trackbuf+cnt*512), 512);
849	raw += 256;
850
851	return raw;
852}
853
854static void amiga_write(int disk)
855{
856	unsigned int cnt;
857	unsigned long *ptr = (unsigned long *)raw_buf;
858
859	disk&=3;
860	/* gap space */
861	for (cnt = 0; cnt < 415 * unit[disk].type->sect_mult; cnt++)
862		*ptr++ = 0xaaaaaaaa;
863
864	/* sectors */
865	for (cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
866		ptr = putsec (disk, ptr, cnt);
867	*(ushort *)ptr = (ptr[-1]&1) ? 0x2AA8 : 0xAAA8;
868}
869
870
871struct dos_header {
872	unsigned char track,   /* 0-80 */
873		side,    /* 0-1 */
874		sec,     /* 0-...*/
875		len_desc;/* 2 */
876	unsigned short crc;     /* on 68000 we got an alignment problem,
877				   but this compiler solves it  by adding silently
878				   adding a pad byte so data won't fit
879				   and this took about 3h to discover.... */
880	unsigned char gap1[22];     /* for longword-alignedness (0x4e) */
881};
882
883/* crc routines are borrowed from the messydos-handler  */
884
885/* excerpt from the messydos-device
886; The CRC is computed not only over the actual data, but including
887; the SYNC mark (3 * $a1) and the 'ID/DATA - Address Mark' ($fe/$fb).
888; As we don't read or encode these fields into our buffers, we have to
889; preload the registers containing the CRC with the values they would have
890; after stepping over these fields.
891;
892; How CRCs "really" work:
893;
894; First, you should regard a bitstring as a series of coefficients of
895; polynomials. We calculate with these polynomials in modulo-2
896; arithmetic, in which both add and subtract are done the same as
897; exclusive-or. Now, we modify our data (a very long polynomial) in
898; such a way that it becomes divisible by the CCITT-standard 16-bit
899;		 16   12   5
900; polynomial:	x  + x	+ x + 1, represented by $11021. The easiest
901; way to do this would be to multiply (using proper arithmetic) our
902; datablock with $11021. So we have:
903;   data * $11021		 =
904;   data * ($10000 + $1021)      =
905;   data * $10000 + data * $1021
906; The left part of this is simple: Just add two 0 bytes. But then
907; the right part (data $1021) remains difficult and even could have
908; a carry into the left part. The solution is to use a modified
909; multiplication, which has a result that is not correct, but with
910; a difference of any multiple of $11021. We then only need to keep
911; the 16 least significant bits of the result.
912;
913; The following algorithm does this for us:
914;
915;   unsigned char *data, c, crclo, crchi;
916;   while (not done) {
917;	c = *data++ + crchi;
918;	crchi = (@ c) >> 8 + crclo;
919;	crclo = @ c;
920;   }
921;
922; Remember, + is done with EOR, the @ operator is in two tables (high
923; and low byte separately), which is calculated as
924;
925;      $1021 * (c & $F0)
926;  xor $1021 * (c & $0F)
927;  xor $1021 * (c >> 4)         (* is regular multiplication)
928;
929;
930; Anyway, the end result is the same as the remainder of the division of
931; the data by $11021. I am afraid I need to study theory a bit more...
932
933
934my only works was to code this from manx to C....
935
936*/
937
938static ushort dos_crc(void * data_a3, int data_d0, int data_d1, int data_d3)
939{
940	static unsigned char CRCTable1[] = {
941		0x00,0x10,0x20,0x30,0x40,0x50,0x60,0x70,0x81,0x91,0xa1,0xb1,0xc1,0xd1,0xe1,0xf1,
942		0x12,0x02,0x32,0x22,0x52,0x42,0x72,0x62,0x93,0x83,0xb3,0xa3,0xd3,0xc3,0xf3,0xe3,
943		0x24,0x34,0x04,0x14,0x64,0x74,0x44,0x54,0xa5,0xb5,0x85,0x95,0xe5,0xf5,0xc5,0xd5,
944		0x36,0x26,0x16,0x06,0x76,0x66,0x56,0x46,0xb7,0xa7,0x97,0x87,0xf7,0xe7,0xd7,0xc7,
945		0x48,0x58,0x68,0x78,0x08,0x18,0x28,0x38,0xc9,0xd9,0xe9,0xf9,0x89,0x99,0xa9,0xb9,
946		0x5a,0x4a,0x7a,0x6a,0x1a,0x0a,0x3a,0x2a,0xdb,0xcb,0xfb,0xeb,0x9b,0x8b,0xbb,0xab,
947		0x6c,0x7c,0x4c,0x5c,0x2c,0x3c,0x0c,0x1c,0xed,0xfd,0xcd,0xdd,0xad,0xbd,0x8d,0x9d,
948		0x7e,0x6e,0x5e,0x4e,0x3e,0x2e,0x1e,0x0e,0xff,0xef,0xdf,0xcf,0xbf,0xaf,0x9f,0x8f,
949		0x91,0x81,0xb1,0xa1,0xd1,0xc1,0xf1,0xe1,0x10,0x00,0x30,0x20,0x50,0x40,0x70,0x60,
950		0x83,0x93,0xa3,0xb3,0xc3,0xd3,0xe3,0xf3,0x02,0x12,0x22,0x32,0x42,0x52,0x62,0x72,
951		0xb5,0xa5,0x95,0x85,0xf5,0xe5,0xd5,0xc5,0x34,0x24,0x14,0x04,0x74,0x64,0x54,0x44,
952		0xa7,0xb7,0x87,0x97,0xe7,0xf7,0xc7,0xd7,0x26,0x36,0x06,0x16,0x66,0x76,0x46,0x56,
953		0xd9,0xc9,0xf9,0xe9,0x99,0x89,0xb9,0xa9,0x58,0x48,0x78,0x68,0x18,0x08,0x38,0x28,
954		0xcb,0xdb,0xeb,0xfb,0x8b,0x9b,0xab,0xbb,0x4a,0x5a,0x6a,0x7a,0x0a,0x1a,0x2a,0x3a,
955		0xfd,0xed,0xdd,0xcd,0xbd,0xad,0x9d,0x8d,0x7c,0x6c,0x5c,0x4c,0x3c,0x2c,0x1c,0x0c,
956		0xef,0xff,0xcf,0xdf,0xaf,0xbf,0x8f,0x9f,0x6e,0x7e,0x4e,0x5e,0x2e,0x3e,0x0e,0x1e
957	};
958
959	static unsigned char CRCTable2[] = {
960		0x00,0x21,0x42,0x63,0x84,0xa5,0xc6,0xe7,0x08,0x29,0x4a,0x6b,0x8c,0xad,0xce,0xef,
961		0x31,0x10,0x73,0x52,0xb5,0x94,0xf7,0xd6,0x39,0x18,0x7b,0x5a,0xbd,0x9c,0xff,0xde,
962		0x62,0x43,0x20,0x01,0xe6,0xc7,0xa4,0x85,0x6a,0x4b,0x28,0x09,0xee,0xcf,0xac,0x8d,
963		0x53,0x72,0x11,0x30,0xd7,0xf6,0x95,0xb4,0x5b,0x7a,0x19,0x38,0xdf,0xfe,0x9d,0xbc,
964		0xc4,0xe5,0x86,0xa7,0x40,0x61,0x02,0x23,0xcc,0xed,0x8e,0xaf,0x48,0x69,0x0a,0x2b,
965		0xf5,0xd4,0xb7,0x96,0x71,0x50,0x33,0x12,0xfd,0xdc,0xbf,0x9e,0x79,0x58,0x3b,0x1a,
966		0xa6,0x87,0xe4,0xc5,0x22,0x03,0x60,0x41,0xae,0x8f,0xec,0xcd,0x2a,0x0b,0x68,0x49,
967		0x97,0xb6,0xd5,0xf4,0x13,0x32,0x51,0x70,0x9f,0xbe,0xdd,0xfc,0x1b,0x3a,0x59,0x78,
968		0x88,0xa9,0xca,0xeb,0x0c,0x2d,0x4e,0x6f,0x80,0xa1,0xc2,0xe3,0x04,0x25,0x46,0x67,
969		0xb9,0x98,0xfb,0xda,0x3d,0x1c,0x7f,0x5e,0xb1,0x90,0xf3,0xd2,0x35,0x14,0x77,0x56,
970		0xea,0xcb,0xa8,0x89,0x6e,0x4f,0x2c,0x0d,0xe2,0xc3,0xa0,0x81,0x66,0x47,0x24,0x05,
971		0xdb,0xfa,0x99,0xb8,0x5f,0x7e,0x1d,0x3c,0xd3,0xf2,0x91,0xb0,0x57,0x76,0x15,0x34,
972		0x4c,0x6d,0x0e,0x2f,0xc8,0xe9,0x8a,0xab,0x44,0x65,0x06,0x27,0xc0,0xe1,0x82,0xa3,
973		0x7d,0x5c,0x3f,0x1e,0xf9,0xd8,0xbb,0x9a,0x75,0x54,0x37,0x16,0xf1,0xd0,0xb3,0x92,
974		0x2e,0x0f,0x6c,0x4d,0xaa,0x8b,0xe8,0xc9,0x26,0x07,0x64,0x45,0xa2,0x83,0xe0,0xc1,
975		0x1f,0x3e,0x5d,0x7c,0x9b,0xba,0xd9,0xf8,0x17,0x36,0x55,0x74,0x93,0xb2,0xd1,0xf0
976	};
977
978/* look at the asm-code - what looks in C a bit strange is almost as good as handmade */
979	register int i;
980	register unsigned char *CRCT1, *CRCT2, *data, c, crch, crcl;
981
982	CRCT1=CRCTable1;
983	CRCT2=CRCTable2;
984	data=data_a3;
985	crcl=data_d1;
986	crch=data_d0;
987	for (i=data_d3; i>=0; i--) {
988		c = (*data++) ^ crch;
989		crch = CRCT1[c] ^ crcl;
990		crcl = CRCT2[c];
991	}
992	return (crch<<8)|crcl;
993}
994
995static inline ushort dos_hdr_crc (struct dos_header *hdr)
996{
997	return dos_crc(&(hdr->track), 0xb2, 0x30, 3); /* precomputed magic */
998}
999
1000static inline ushort dos_data_crc(unsigned char *data)
1001{
1002	return dos_crc(data, 0xe2, 0x95 ,511); /* precomputed magic */
1003}
1004
1005static inline unsigned char dos_decode_byte(ushort word)
1006{
1007	register ushort w2;
1008	register unsigned char byte;
1009	register unsigned char *dec = mfmdecode;
1010
1011	w2=word;
1012	w2>>=8;
1013	w2&=127;
1014	byte = dec[w2];
1015	byte <<= 4;
1016	w2 = word & 127;
1017	byte |= dec[w2];
1018	return byte;
1019}
1020
1021static unsigned long dos_decode(unsigned char *data, unsigned short *raw, int len)
1022{
1023	int i;
1024
1025	for (i = 0; i < len; i++)
1026		*data++=dos_decode_byte(*raw++);
1027	return ((ulong)raw);
1028}
1029
1030#ifdef DEBUG
1031static void dbg(unsigned long ptr)
1032{
1033	printk("raw data @%08lx: %08lx, %08lx ,%08lx, %08lx\n", ptr,
1034	       ((ulong *)ptr)[0], ((ulong *)ptr)[1],
1035	       ((ulong *)ptr)[2], ((ulong *)ptr)[3]);
1036}
1037#endif
1038
1039static int dos_read(int drive)
1040{
1041	unsigned long end;
1042	unsigned long raw;
1043	int scnt;
1044	unsigned short crc,data_crc[2];
1045	struct dos_header hdr;
1046
1047	drive&=3;
1048	raw = (long) raw_buf;
1049	end = raw + unit[drive].type->read_size;
1050
1051	for (scnt=0; scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
1052		do { /* search for the right sync of each sec-hdr */
1053			if (!(raw = scan_sync (raw, end))) {
1054				printk(KERN_INFO "dos_read: no hdr sync on "
1055				       "track %d, unit %d for sector %d\n",
1056				       unit[drive].track,drive,scnt);
1057				return MFM_NOSYNC;
1058			}
1059#ifdef DEBUG
1060			dbg(raw);
1061#endif
1062		} while (*((ushort *)raw)!=0x5554); /* loop usually only once done */
1063		raw+=2; /* skip over headermark */
1064		raw = dos_decode((unsigned char *)&hdr,(ushort *) raw,8);
1065		crc = dos_hdr_crc(&hdr);
1066
1067#ifdef DEBUG
1068		printk("(%3d,%d,%2d,%d) %x\n", hdr.track, hdr.side,
1069		       hdr.sec, hdr.len_desc, hdr.crc);
1070#endif
1071
1072		if (crc != hdr.crc) {
1073			printk(KERN_INFO "dos_read: MFM_HEADER %04x,%04x\n",
1074			       hdr.crc, crc);
1075			return MFM_HEADER;
1076		}
1077		if (hdr.track != unit[drive].track/unit[drive].type->heads) {
1078			printk(KERN_INFO "dos_read: MFM_TRACK %d, %d\n",
1079			       hdr.track,
1080			       unit[drive].track/unit[drive].type->heads);
1081			return MFM_TRACK;
1082		}
1083
1084		if (hdr.side != unit[drive].track%unit[drive].type->heads) {
1085			printk(KERN_INFO "dos_read: MFM_SIDE %d, %d\n",
1086			       hdr.side,
1087			       unit[drive].track%unit[drive].type->heads);
1088			return MFM_TRACK;
1089		}
1090
1091		if (hdr.len_desc != 2) {
1092			printk(KERN_INFO "dos_read: unknown sector len "
1093			       "descriptor %d\n", hdr.len_desc);
1094			return MFM_DATA;
1095		}
1096#ifdef DEBUG
1097		printk("hdr accepted\n");
1098#endif
1099		if (!(raw = scan_sync (raw, end))) {
1100			printk(KERN_INFO "dos_read: no data sync on track "
1101			       "%d, unit %d for sector%d, disk sector %d\n",
1102			       unit[drive].track, drive, scnt, hdr.sec);
1103			return MFM_NOSYNC;
1104		}
1105#ifdef DEBUG
1106		dbg(raw);
1107#endif
1108
1109		if (*((ushort *)raw)!=0x5545) {
1110			printk(KERN_INFO "dos_read: no data mark after "
1111			       "sync (%d,%d,%d,%d) sc=%d\n",
1112			       hdr.track,hdr.side,hdr.sec,hdr.len_desc,scnt);
1113			return MFM_NOSYNC;
1114		}
1115
1116		raw+=2;  /* skip data mark (included in checksum) */
1117		raw = dos_decode((unsigned char *)(unit[drive].trackbuf + (hdr.sec - 1) * 512), (ushort *) raw, 512);
1118		raw = dos_decode((unsigned char  *)data_crc,(ushort *) raw,4);
1119		crc = dos_data_crc(unit[drive].trackbuf + (hdr.sec - 1) * 512);
1120
1121		if (crc != data_crc[0]) {
1122			printk(KERN_INFO "dos_read: MFM_DATA (%d,%d,%d,%d) "
1123			       "sc=%d, %x %x\n", hdr.track, hdr.side,
1124			       hdr.sec, hdr.len_desc, scnt,data_crc[0], crc);
1125			printk(KERN_INFO "data=(%lx,%lx,%lx,%lx,...)\n",
1126			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[0],
1127			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[1],
1128			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[2],
1129			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[3]);
1130			return MFM_DATA;
1131		}
1132	}
1133	return 0;
1134}
1135
1136static inline ushort dos_encode_byte(unsigned char byte)
1137{
1138	register unsigned char *enc, b2, b1;
1139	register ushort word;
1140
1141	enc=mfmencode;
1142	b1=byte;
1143	b2=b1>>4;
1144	b1&=15;
1145	word=enc[b2] <<8 | enc [b1];
1146	return (word|((word&(256|64)) ? 0: 128));
1147}
1148
1149static void dos_encode_block(ushort *dest, unsigned char *src, int len)
1150{
1151	int i;
1152
1153	for (i = 0; i < len; i++) {
1154		*dest=dos_encode_byte(*src++);
1155		*dest|=((dest[-1]&1)||(*dest&0x4000))? 0: 0x8000;
1156		dest++;
1157	}
1158}
1159
1160static unsigned long *ms_putsec(int drive, unsigned long *raw, int cnt)
1161{
1162	static struct dos_header hdr={0,0,0,2,0,
1163	  {78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78}};
1164	int i;
1165	static ushort crc[2]={0,0x4e4e};
1166
1167	drive&=3;
1168/* id gap 1 */
1169/* the MFM word before is always 9254 */
1170	for(i=0;i<6;i++)
1171		*raw++=0xaaaaaaaa;
1172/* 3 sync + 1 headermark */
1173	*raw++=0x44894489;
1174	*raw++=0x44895554;
1175
1176/* fill in the variable parts of the header */
1177	hdr.track=unit[drive].track/unit[drive].type->heads;
1178	hdr.side=unit[drive].track%unit[drive].type->heads;
1179	hdr.sec=cnt+1;
1180	hdr.crc=dos_hdr_crc(&hdr);
1181
1182/* header (without "magic") and id gap 2*/
1183	dos_encode_block((ushort *)raw,(unsigned char *) &hdr.track,28);
1184	raw+=14;
1185
1186/*id gap 3 */
1187	for(i=0;i<6;i++)
1188		*raw++=0xaaaaaaaa;
1189
1190/* 3 syncs and 1 datamark */
1191	*raw++=0x44894489;
1192	*raw++=0x44895545;
1193
1194/* data */
1195	dos_encode_block((ushort *)raw,
1196			 (unsigned char *)unit[drive].trackbuf+cnt*512,512);
1197	raw+=256;
1198
1199/*data crc + jd's special gap (long words :-/) */
1200	crc[0]=dos_data_crc(unit[drive].trackbuf+cnt*512);
1201	dos_encode_block((ushort *) raw,(unsigned char *)crc,4);
1202	raw+=2;
1203
1204/* data gap */
1205	for(i=0;i<38;i++)
1206		*raw++=0x92549254;
1207
1208	return raw; /* wrote 652 MFM words */
1209}
1210
1211static void dos_write(int disk)
1212{
1213	int cnt;
1214	unsigned long raw = (unsigned long) raw_buf;
1215	unsigned long *ptr=(unsigned long *)raw;
1216
1217	disk&=3;
1218/* really gap4 + indexgap , but we write it first and round it up */
1219	for (cnt=0;cnt<425;cnt++)
1220		*ptr++=0x92549254;
1221
1222/* the following is just guessed */
1223	if (unit[disk].type->sect_mult==2)  /* check for HD-Disks */
1224		for(cnt=0;cnt<473;cnt++)
1225			*ptr++=0x92549254;
1226
1227/* now the index marks...*/
1228	for (cnt=0;cnt<20;cnt++)
1229		*ptr++=0x92549254;
1230	for (cnt=0;cnt<6;cnt++)
1231		*ptr++=0xaaaaaaaa;
1232	*ptr++=0x52245224;
1233	*ptr++=0x52245552;
1234	for (cnt=0;cnt<20;cnt++)
1235		*ptr++=0x92549254;
1236
1237/* sectors */
1238	for(cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
1239		ptr=ms_putsec(disk,ptr,cnt);
1240
1241	*(ushort *)ptr = 0xaaa8; /* MFM word before is always 0x9254 */
1242}
1243
1244/*
1245 * Here comes the high level stuff (i.e. the filesystem interface)
1246 * and helper functions.
1247 * Normally this should be the only part that has to be adapted to
1248 * different kernel versions.
1249 */
1250
1251/* FIXME: this assumes the drive is still spinning -
1252 * which is only true if we complete writing a track within three seconds
1253 */
1254static void flush_track_callback(unsigned long nr)
1255{
1256	nr&=3;
1257	writefromint = 1;
1258	if (!try_fdc(nr)) {
1259		/* we might block in an interrupt, so try again later */
1260		flush_track_timer[nr].expires = jiffies + 1;
1261		add_timer(flush_track_timer + nr);
1262		return;
1263	}
1264	get_fdc(nr);
1265	(*unit[nr].dtype->write_fkt)(nr);
1266	if (!raw_write(nr)) {
1267		printk (KERN_NOTICE "floppy disk write protected\n");
1268		writefromint = 0;
1269		writepending = 0;
1270	}
1271	rel_fdc();
1272}
1273
1274static int non_int_flush_track (unsigned long nr)
1275{
1276	unsigned long flags;
1277
1278	nr&=3;
1279	writefromint = 0;
1280	del_timer(&post_write_timer);
1281	get_fdc(nr);
1282	if (!fd_motor_on(nr)) {
1283		writepending = 0;
1284		rel_fdc();
1285		return 0;
1286	}
1287	local_irq_save(flags);
1288	if (writepending != 2) {
1289		local_irq_restore(flags);
1290		(*unit[nr].dtype->write_fkt)(nr);
1291		if (!raw_write(nr)) {
1292			printk (KERN_NOTICE "floppy disk write protected "
1293				"in write!\n");
1294			writepending = 0;
1295			return 0;
1296		}
1297		while (block_flag == 2)
1298			sleep_on (&wait_fd_block);
1299	}
1300	else {
1301		local_irq_restore(flags);
1302		ms_delay(2); /* 2 ms post_write delay */
1303		post_write(nr);
1304	}
1305	rel_fdc();
1306	return 1;
1307}
1308
1309static int get_track(int drive, int track)
1310{
1311	int error, errcnt;
1312
1313	drive&=3;
1314	if (unit[drive].track == track)
1315		return 0;
1316	get_fdc(drive);
1317	if (!fd_motor_on(drive)) {
1318		rel_fdc();
1319		return -1;
1320	}
1321
1322	if (unit[drive].dirty == 1) {
1323		del_timer (flush_track_timer + drive);
1324		non_int_flush_track (drive);
1325	}
1326	errcnt = 0;
1327	while (errcnt < MAX_ERRORS) {
1328		if (!fd_seek(drive, track))
1329			return -1;
1330		raw_read(drive);
1331		error = (*unit[drive].dtype->read_fkt)(drive);
1332		if (error == 0) {
1333			rel_fdc();
1334			return 0;
1335		}
1336		/* Read Error Handling: recalibrate and try again */
1337		unit[drive].track = -1;
1338		errcnt++;
1339	}
1340	rel_fdc();
1341	return -1;
1342}
1343
1344static void redo_fd_request(void)
1345{
1346	unsigned int cnt, block, track, sector;
1347	int drive;
1348	struct amiga_floppy_struct *floppy;
1349	char *data;
1350	unsigned long flags;
1351
1352 repeat:
1353	if (!CURRENT) {
1354		/* Nothing left to do */
1355		return;
1356	}
1357
1358	floppy = CURRENT->rq_disk->private_data;
1359	drive = floppy - unit;
1360
1361	/* Here someone could investigate to be more efficient */
1362	for (cnt = 0; cnt < CURRENT->current_nr_sectors; cnt++) {
1363#ifdef DEBUG
1364		printk("fd: sector %ld + %d requested for %s\n",
1365		       CURRENT->sector,cnt,
1366		       (CURRENT->cmd==READ)?"read":"write");
1367#endif
1368		block = CURRENT->sector + cnt;
1369		if ((int)block > floppy->blocks) {
1370			end_request(CURRENT, 0);
1371			goto repeat;
1372		}
1373
1374		track = block / (floppy->dtype->sects * floppy->type->sect_mult);
1375		sector = block % (floppy->dtype->sects * floppy->type->sect_mult);
1376		data = CURRENT->buffer + 512 * cnt;
1377#ifdef DEBUG
1378		printk("access to track %d, sector %d, with buffer at "
1379		       "0x%08lx\n", track, sector, data);
1380#endif
1381
1382		if ((rq_data_dir(CURRENT) != READ) && (rq_data_dir(CURRENT) != WRITE)) {
1383			printk(KERN_WARNING "do_fd_request: unknown command\n");
1384			end_request(CURRENT, 0);
1385			goto repeat;
1386		}
1387		if (get_track(drive, track) == -1) {
1388			end_request(CURRENT, 0);
1389			goto repeat;
1390		}
1391
1392		switch (rq_data_dir(CURRENT)) {
1393		case READ:
1394			memcpy(data, floppy->trackbuf + sector * 512, 512);
1395			break;
1396
1397		case WRITE:
1398			memcpy(floppy->trackbuf + sector * 512, data, 512);
1399
1400			/* keep the drive spinning while writes are scheduled */
1401			if (!fd_motor_on(drive)) {
1402				end_request(CURRENT, 0);
1403				goto repeat;
1404			}
1405			/*
1406			 * setup a callback to write the track buffer
1407			 * after a short (1 tick) delay.
1408			 */
1409			local_irq_save(flags);
1410
1411			floppy->dirty = 1;
1412		        /* reset the timer */
1413			mod_timer (flush_track_timer + drive, jiffies + 1);
1414			local_irq_restore(flags);
1415			break;
1416		}
1417	}
1418	CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
1419	CURRENT->sector += CURRENT->current_nr_sectors;
1420
1421	end_request(CURRENT, 1);
1422	goto repeat;
1423}
1424
1425static void do_fd_request(request_queue_t * q)
1426{
1427	redo_fd_request();
1428}
1429
1430static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1431{
1432	int drive = MINOR(bdev->bd_dev) & 3;
1433
1434	geo->heads = unit[drive].type->heads;
1435	geo->sectors = unit[drive].dtype->sects * unit[drive].type->sect_mult;
1436	geo->cylinders = unit[drive].type->tracks;
1437	return 0;
1438}
1439
1440static int fd_ioctl(struct inode *inode, struct file *filp,
1441		    unsigned int cmd, unsigned long param)
1442{
1443	int drive = iminor(inode) & 3;
1444	static struct floppy_struct getprm;
1445	void __user *argp = (void __user *)param;
1446
1447	switch(cmd){
1448	case FDFMTBEG:
1449		get_fdc(drive);
1450		if (fd_ref[drive] > 1) {
1451			rel_fdc();
1452			return -EBUSY;
1453		}
1454		fsync_bdev(inode->i_bdev);
1455		if (fd_motor_on(drive) == 0) {
1456			rel_fdc();
1457			return -ENODEV;
1458		}
1459		if (fd_calibrate(drive) == 0) {
1460			rel_fdc();
1461			return -ENXIO;
1462		}
1463		floppy_off(drive);
1464		rel_fdc();
1465		break;
1466	case FDFMTTRK:
1467		if (param < unit[drive].type->tracks * unit[drive].type->heads)
1468		{
1469			get_fdc(drive);
1470			if (fd_seek(drive,param) != 0){
1471				memset(unit[drive].trackbuf, FD_FILL_BYTE,
1472				       unit[drive].dtype->sects * unit[drive].type->sect_mult * 512);
1473				non_int_flush_track(drive);
1474			}
1475			floppy_off(drive);
1476			rel_fdc();
1477		}
1478		else
1479			return -EINVAL;
1480		break;
1481	case FDFMTEND:
1482		floppy_off(drive);
1483		invalidate_bdev(inode->i_bdev, 0);
1484		break;
1485	case FDGETPRM:
1486		memset((void *)&getprm, 0, sizeof (getprm));
1487		getprm.track=unit[drive].type->tracks;
1488		getprm.head=unit[drive].type->heads;
1489		getprm.sect=unit[drive].dtype->sects * unit[drive].type->sect_mult;
1490		getprm.size=unit[drive].blocks;
1491		if (copy_to_user(argp, &getprm, sizeof(struct floppy_struct)))
1492			return -EFAULT;
1493		break;
1494	case FDSETPRM:
1495	case FDDEFPRM:
1496		return -EINVAL;
1497	case FDFLUSH: /* unconditionally, even if not needed */
1498		del_timer (flush_track_timer + drive);
1499		non_int_flush_track(drive);
1500		break;
1501#ifdef RAW_IOCTL
1502	case IOCTL_RAW_TRACK:
1503		if (copy_to_user(argp, raw_buf, unit[drive].type->read_size))
1504			return -EFAULT;
1505		else
1506			return unit[drive].type->read_size;
1507#endif
1508	default:
1509		printk(KERN_DEBUG "fd_ioctl: unknown cmd %d for drive %d.",
1510		       cmd, drive);
1511		return -ENOSYS;
1512	}
1513	return 0;
1514}
1515
1516static void fd_probe(int dev)
1517{
1518	unsigned long code;
1519	int type;
1520	int drive;
1521
1522	drive = dev & 3;
1523	code = fd_get_drive_id(drive);
1524
1525	/* get drive type */
1526	for (type = 0; type < num_dr_types; type++)
1527		if (drive_types[type].code == code)
1528			break;
1529
1530	if (type >= num_dr_types) {
1531		printk(KERN_WARNING "fd_probe: unsupported drive type "
1532		       "%08lx found\n", code);
1533		unit[drive].type = &drive_types[num_dr_types-1]; /* FD_NODRIVE */
1534		return;
1535	}
1536
1537	unit[drive].type = drive_types + type;
1538	unit[drive].track = -1;
1539
1540	unit[drive].disk = -1;
1541	unit[drive].motor = 0;
1542	unit[drive].busy = 0;
1543	unit[drive].status = -1;
1544}
1545
1546/*
1547 * floppy_open check for aliasing (/dev/fd0 can be the same as
1548 * /dev/PS0 etc), and disallows simultaneous access to the same
1549 * drive with different device numbers.
1550 */
1551static int floppy_open(struct inode *inode, struct file *filp)
1552{
1553	int drive = iminor(inode) & 3;
1554	int system =  (iminor(inode) & 4) >> 2;
1555	int old_dev;
1556	unsigned long flags;
1557
1558	old_dev = fd_device[drive];
1559
1560	if (fd_ref[drive] && old_dev != system)
1561		return -EBUSY;
1562
1563	if (filp && filp->f_mode & 3) {
1564		check_disk_change(inode->i_bdev);
1565		if (filp->f_mode & 2 ) {
1566			int wrprot;
1567
1568			get_fdc(drive);
1569			fd_select (drive);
1570			wrprot = !(ciaa.pra & DSKPROT);
1571			fd_deselect (drive);
1572			rel_fdc();
1573
1574			if (wrprot)
1575				return -EROFS;
1576		}
1577	}
1578
1579	local_irq_save(flags);
1580	fd_ref[drive]++;
1581	fd_device[drive] = system;
1582	local_irq_restore(flags);
1583
1584	unit[drive].dtype=&data_types[system];
1585	unit[drive].blocks=unit[drive].type->heads*unit[drive].type->tracks*
1586		data_types[system].sects*unit[drive].type->sect_mult;
1587	set_capacity(unit[drive].gendisk, unit[drive].blocks);
1588
1589	printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
1590	       unit[drive].type->name, data_types[system].name);
1591
1592	return 0;
1593}
1594
1595static int floppy_release(struct inode * inode, struct file * filp)
1596{
1597	int drive = iminor(inode) & 3;
1598
1599	if (unit[drive].dirty == 1) {
1600		del_timer (flush_track_timer + drive);
1601		non_int_flush_track (drive);
1602	}
1603
1604	if (!fd_ref[drive]--) {
1605		printk(KERN_CRIT "floppy_release with fd_ref == 0");
1606		fd_ref[drive] = 0;
1607	}
1608#ifdef MODULE
1609/* the mod_use counter is handled this way */
1610	floppy_off (drive | 0x40000000);
1611#endif
1612	return 0;
1613}
1614
1615/*
1616 * floppy-change is never called from an interrupt, so we can relax a bit
1617 * here, sleep etc. Note that floppy-on tries to set current_DOR to point
1618 * to the desired drive, but it will probably not survive the sleep if
1619 * several floppies are used at the same time: thus the loop.
1620 */
1621static int amiga_floppy_change(struct gendisk *disk)
1622{
1623	struct amiga_floppy_struct *p = disk->private_data;
1624	int drive = p - unit;
1625	int changed;
1626	static int first_time = 1;
1627
1628	if (first_time)
1629		changed = first_time--;
1630	else {
1631		get_fdc(drive);
1632		fd_select (drive);
1633		changed = !(ciaa.pra & DSKCHANGE);
1634		fd_deselect (drive);
1635		rel_fdc();
1636	}
1637
1638	if (changed) {
1639		fd_probe(drive);
1640		p->track = -1;
1641		p->dirty = 0;
1642		writepending = 0; /* if this was true before, too bad! */
1643		writefromint = 0;
1644		return 1;
1645	}
1646	return 0;
1647}
1648
1649static struct block_device_operations floppy_fops = {
1650	.owner		= THIS_MODULE,
1651	.open		= floppy_open,
1652	.release	= floppy_release,
1653	.ioctl		= fd_ioctl,
1654	.getgeo		= fd_getgeo,
1655	.media_changed	= amiga_floppy_change,
1656};
1657
1658static int __init fd_probe_drives(void)
1659{
1660	int drive,drives,nomem;
1661
1662	printk(KERN_INFO "FD: probing units\n" KERN_INFO "found ");
1663	drives=0;
1664	nomem=0;
1665	for(drive=0;drive<FD_MAX_UNITS;drive++) {
1666		struct gendisk *disk;
1667		fd_probe(drive);
1668		if (unit[drive].type->code == FD_NODRIVE)
1669			continue;
1670		disk = alloc_disk(1);
1671		if (!disk) {
1672			unit[drive].type->code = FD_NODRIVE;
1673			continue;
1674		}
1675		unit[drive].gendisk = disk;
1676		drives++;
1677		if ((unit[drive].trackbuf = kmalloc(FLOPPY_MAX_SECTORS * 512, GFP_KERNEL)) == NULL) {
1678			printk("no mem for ");
1679			unit[drive].type = &drive_types[num_dr_types - 1]; /* FD_NODRIVE */
1680			drives--;
1681			nomem = 1;
1682		}
1683		printk("fd%d ",drive);
1684		disk->major = FLOPPY_MAJOR;
1685		disk->first_minor = drive;
1686		disk->fops = &floppy_fops;
1687		sprintf(disk->disk_name, "fd%d", drive);
1688		disk->private_data = &unit[drive];
1689		disk->queue = floppy_queue;
1690		set_capacity(disk, 880*2);
1691		add_disk(disk);
1692	}
1693	if ((drives > 0) || (nomem == 0)) {
1694		if (drives == 0)
1695			printk("no drives");
1696		printk("\n");
1697		return drives;
1698	}
1699	printk("\n");
1700	return -ENOMEM;
1701}
1702
1703static struct kobject *floppy_find(dev_t dev, int *part, void *data)
1704{
1705	int drive = *part & 3;
1706	if (unit[drive].type->code == FD_NODRIVE)
1707		return NULL;
1708	*part = 0;
1709	return get_disk(unit[drive].gendisk);
1710}
1711
1712int __init amiga_floppy_init(void)
1713{
1714	int i, ret;
1715
1716	if (!AMIGAHW_PRESENT(AMI_FLOPPY))
1717		return -ENXIO;
1718
1719	if (register_blkdev(FLOPPY_MAJOR,"fd"))
1720		return -EBUSY;
1721
1722	/*
1723	 *  We request DSKPTR, DSKLEN and DSKDATA only, because the other
1724	 *  floppy registers are too spreaded over the custom register space
1725	 */
1726	ret = -EBUSY;
1727	if (!request_mem_region(CUSTOM_PHYSADDR+0x20, 8, "amiflop [Paula]")) {
1728		printk("fd: cannot get floppy registers\n");
1729		goto out_blkdev;
1730	}
1731
1732	ret = -ENOMEM;
1733	if ((raw_buf = (char *)amiga_chip_alloc (RAW_BUF_SIZE, "Floppy")) ==
1734	    NULL) {
1735		printk("fd: cannot get chip mem buffer\n");
1736		goto out_memregion;
1737	}
1738
1739	ret = -EBUSY;
1740	if (request_irq(IRQ_AMIGA_DSKBLK, fd_block_done, 0, "floppy_dma", NULL)) {
1741		printk("fd: cannot get irq for dma\n");
1742		goto out_irq;
1743	}
1744
1745	if (request_irq(IRQ_AMIGA_CIAA_TB, ms_isr, 0, "floppy_timer", NULL)) {
1746		printk("fd: cannot get irq for timer\n");
1747		goto out_irq2;
1748	}
1749
1750	ret = -ENOMEM;
1751	floppy_queue = blk_init_queue(do_fd_request, &amiflop_lock);
1752	if (!floppy_queue)
1753		goto out_queue;
1754
1755	ret = -ENXIO;
1756	if (fd_probe_drives() < 1) /* No usable drives */
1757		goto out_probe;
1758
1759	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
1760				floppy_find, NULL, NULL);
1761
1762	/* initialize variables */
1763	init_timer(&motor_on_timer);
1764	motor_on_timer.expires = 0;
1765	motor_on_timer.data = 0;
1766	motor_on_timer.function = motor_on_callback;
1767	for (i = 0; i < FD_MAX_UNITS; i++) {
1768		init_timer(&motor_off_timer[i]);
1769		motor_off_timer[i].expires = 0;
1770		motor_off_timer[i].data = i|0x80000000;
1771		motor_off_timer[i].function = fd_motor_off;
1772		init_timer(&flush_track_timer[i]);
1773		flush_track_timer[i].expires = 0;
1774		flush_track_timer[i].data = i;
1775		flush_track_timer[i].function = flush_track_callback;
1776
1777		unit[i].track = -1;
1778	}
1779
1780	init_timer(&post_write_timer);
1781	post_write_timer.expires = 0;
1782	post_write_timer.data = 0;
1783	post_write_timer.function = post_write;
1784
1785	for (i = 0; i < 128; i++)
1786		mfmdecode[i]=255;
1787	for (i = 0; i < 16; i++)
1788		mfmdecode[mfmencode[i]]=i;
1789
1790	/* make sure that disk DMA is enabled */
1791	custom.dmacon = DMAF_SETCLR | DMAF_DISK;
1792
1793	/* init ms timer */
1794	ciaa.crb = 8; /* one-shot, stop */
1795	return 0;
1796
1797out_probe:
1798	blk_cleanup_queue(floppy_queue);
1799out_queue:
1800	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1801out_irq2:
1802	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1803out_irq:
1804	amiga_chip_free(raw_buf);
1805out_memregion:
1806	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1807out_blkdev:
1808	unregister_blkdev(FLOPPY_MAJOR,"fd");
1809	return ret;
1810}
1811
1812#ifdef MODULE
1813
1814int init_module(void)
1815{
1816	if (!MACH_IS_AMIGA)
1817		return -ENXIO;
1818	return amiga_floppy_init();
1819}
1820
1821#if 0 /* not safe to unload */
1822void cleanup_module(void)
1823{
1824	int i;
1825
1826	for( i = 0; i < FD_MAX_UNITS; i++) {
1827		if (unit[i].type->code != FD_NODRIVE) {
1828			del_gendisk(unit[i].gendisk);
1829			put_disk(unit[i].gendisk);
1830			kfree(unit[i].trackbuf);
1831		}
1832	}
1833	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
1834	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1835	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1836	custom.dmacon = DMAF_DISK; /* disable DMA */
1837	amiga_chip_free(raw_buf);
1838	blk_cleanup_queue(floppy_queue);
1839	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1840	unregister_blkdev(FLOPPY_MAJOR, "fd");
1841}
1842#endif
1843
1844#else
1845static int __init amiga_floppy_setup (char *str)
1846{
1847	int n;
1848	if (!MACH_IS_AMIGA)
1849		return 0;
1850	if (!get_option(&str, &n))
1851		return 0;
1852	printk (KERN_INFO "amiflop: Setting default df0 to %x\n", n);
1853	fd_def_df0 = n;
1854	return 1;
1855}
1856
1857__setup("floppy=", amiga_floppy_setup);
1858#endif
1859