xref: /openbmc/linux/drivers/block/amiflop.c (revision 22246614)
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 
109 static unsigned long int fd_def_df0 = FD_DD_3;     /* default for df0 if it doesn't identify */
110 
111 module_param(fd_def_df0, ulong, 0);
112 MODULE_LICENSE("GPL");
113 
114 static 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 
127 static 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 };
135 static int num_dr_types = ARRAY_SIZE(drive_types);
136 
137 static int amiga_read(int), dos_read(int);
138 static void amiga_write(int), dos_write(int);
139 static 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 */
145 static struct amiga_floppy_struct unit[FD_MAX_UNITS];
146 
147 static struct timer_list flush_track_timer[FD_MAX_UNITS];
148 static struct timer_list post_write_timer;
149 static struct timer_list motor_on_timer;
150 static struct timer_list motor_off_timer[FD_MAX_UNITS];
151 static int on_attempts;
152 
153 /* Synchronization of FDC access */
154 /* request loop (trackbuffer) */
155 static volatile int fdc_busy = -1;
156 static volatile int fdc_nested;
157 static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
158 
159 static DECLARE_WAIT_QUEUE_HEAD(motor_wait);
160 
161 static volatile int selected = -1;	/* currently selected drive */
162 
163 static int writepending;
164 static int writefromint;
165 static char *raw_buf;
166 
167 static 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  */
176 static volatile char block_flag;
177 static DECLARE_WAIT_QUEUE_HEAD(wait_fd_block);
178 
179 /* MS-Dos MFM Coding tables (should go quick and easy) */
180 static unsigned char mfmencode[16]={
181 	0x2a, 0x29, 0x24, 0x25, 0x12, 0x11, 0x14, 0x15,
182 	0x4a, 0x49, 0x44, 0x45, 0x52, 0x51, 0x54, 0x55
183 };
184 static unsigned char mfmdecode[128];
185 
186 /* floppy internal millisecond timer stuff */
187 static volatile int ms_busy = -1;
188 static 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. */
201 static int fd_ref[4] = { 0,0,0,0 };
202 static 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 
212 static irqreturn_t ms_isr(int irq, void *dummy)
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 */
221 static 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 */
242 static inline int try_fdc(int drive)
243 {
244 	drive &= 3;
245 	return ((fdc_busy < 0) || (fdc_busy == drive));
246 }
247 
248 static 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 
264 static 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 
278 static 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 
302 static 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 
330 static 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 
340 static 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 
372 static 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 
394 static 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 
404 static 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 
456 static 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 
513 static 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 
563 static irqreturn_t fd_block_done(int irq, void *dummy)
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 
581 static 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 
609 static 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  */
645 static 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 
668 static 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 
682 static 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 
694 static 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 
714 struct 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 
724 static 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 
788 static 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 
802 static 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 
820 static 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 
854 static 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 
871 struct 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 
934 my only works was to code this from manx to C....
935 
936 */
937 
938 static 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 
995 static inline ushort dos_hdr_crc (struct dos_header *hdr)
996 {
997 	return dos_crc(&(hdr->track), 0xb2, 0x30, 3); /* precomputed magic */
998 }
999 
1000 static inline ushort dos_data_crc(unsigned char *data)
1001 {
1002 	return dos_crc(data, 0xe2, 0x95 ,511); /* precomputed magic */
1003 }
1004 
1005 static 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 
1021 static 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
1031 static 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 
1039 static 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 
1136 static 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 
1149 static 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 
1160 static 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 
1211 static 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  */
1254 static 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 
1274 static 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 
1309 static 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 
1344 static 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 		       (rq_data_dir(CURRENT) == 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 
1425 static void do_fd_request(struct request_queue * q)
1426 {
1427 	redo_fd_request();
1428 }
1429 
1430 static 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 
1440 static 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);
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 
1516 static 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  */
1551 static 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 
1595 static 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  */
1621 static 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 
1649 static 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 
1658 static 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 
1703 static 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 
1712 static int __init amiga_floppy_init(void)
1713 {
1714 	int i, ret;
1715 
1716 	if (!MACH_IS_AMIGA)
1717 		return -ENXIO;
1718 
1719 	if (!AMIGAHW_PRESENT(AMI_FLOPPY))
1720 		return -ENXIO;
1721 
1722 	if (register_blkdev(FLOPPY_MAJOR,"fd"))
1723 		return -EBUSY;
1724 
1725 	/*
1726 	 *  We request DSKPTR, DSKLEN and DSKDATA only, because the other
1727 	 *  floppy registers are too spreaded over the custom register space
1728 	 */
1729 	ret = -EBUSY;
1730 	if (!request_mem_region(CUSTOM_PHYSADDR+0x20, 8, "amiflop [Paula]")) {
1731 		printk("fd: cannot get floppy registers\n");
1732 		goto out_blkdev;
1733 	}
1734 
1735 	ret = -ENOMEM;
1736 	if ((raw_buf = (char *)amiga_chip_alloc (RAW_BUF_SIZE, "Floppy")) ==
1737 	    NULL) {
1738 		printk("fd: cannot get chip mem buffer\n");
1739 		goto out_memregion;
1740 	}
1741 
1742 	ret = -EBUSY;
1743 	if (request_irq(IRQ_AMIGA_DSKBLK, fd_block_done, 0, "floppy_dma", NULL)) {
1744 		printk("fd: cannot get irq for dma\n");
1745 		goto out_irq;
1746 	}
1747 
1748 	if (request_irq(IRQ_AMIGA_CIAA_TB, ms_isr, 0, "floppy_timer", NULL)) {
1749 		printk("fd: cannot get irq for timer\n");
1750 		goto out_irq2;
1751 	}
1752 
1753 	ret = -ENOMEM;
1754 	floppy_queue = blk_init_queue(do_fd_request, &amiflop_lock);
1755 	if (!floppy_queue)
1756 		goto out_queue;
1757 
1758 	ret = -ENXIO;
1759 	if (fd_probe_drives() < 1) /* No usable drives */
1760 		goto out_probe;
1761 
1762 	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
1763 				floppy_find, NULL, NULL);
1764 
1765 	/* initialize variables */
1766 	init_timer(&motor_on_timer);
1767 	motor_on_timer.expires = 0;
1768 	motor_on_timer.data = 0;
1769 	motor_on_timer.function = motor_on_callback;
1770 	for (i = 0; i < FD_MAX_UNITS; i++) {
1771 		init_timer(&motor_off_timer[i]);
1772 		motor_off_timer[i].expires = 0;
1773 		motor_off_timer[i].data = i|0x80000000;
1774 		motor_off_timer[i].function = fd_motor_off;
1775 		init_timer(&flush_track_timer[i]);
1776 		flush_track_timer[i].expires = 0;
1777 		flush_track_timer[i].data = i;
1778 		flush_track_timer[i].function = flush_track_callback;
1779 
1780 		unit[i].track = -1;
1781 	}
1782 
1783 	init_timer(&post_write_timer);
1784 	post_write_timer.expires = 0;
1785 	post_write_timer.data = 0;
1786 	post_write_timer.function = post_write;
1787 
1788 	for (i = 0; i < 128; i++)
1789 		mfmdecode[i]=255;
1790 	for (i = 0; i < 16; i++)
1791 		mfmdecode[mfmencode[i]]=i;
1792 
1793 	/* make sure that disk DMA is enabled */
1794 	custom.dmacon = DMAF_SETCLR | DMAF_DISK;
1795 
1796 	/* init ms timer */
1797 	ciaa.crb = 8; /* one-shot, stop */
1798 	return 0;
1799 
1800 out_probe:
1801 	blk_cleanup_queue(floppy_queue);
1802 out_queue:
1803 	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1804 out_irq2:
1805 	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1806 out_irq:
1807 	amiga_chip_free(raw_buf);
1808 out_memregion:
1809 	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1810 out_blkdev:
1811 	unregister_blkdev(FLOPPY_MAJOR,"fd");
1812 	return ret;
1813 }
1814 
1815 module_init(amiga_floppy_init);
1816 #ifdef MODULE
1817 
1818 #if 0 /* not safe to unload */
1819 void cleanup_module(void)
1820 {
1821 	int i;
1822 
1823 	for( i = 0; i < FD_MAX_UNITS; i++) {
1824 		if (unit[i].type->code != FD_NODRIVE) {
1825 			del_gendisk(unit[i].gendisk);
1826 			put_disk(unit[i].gendisk);
1827 			kfree(unit[i].trackbuf);
1828 		}
1829 	}
1830 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
1831 	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1832 	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1833 	custom.dmacon = DMAF_DISK; /* disable DMA */
1834 	amiga_chip_free(raw_buf);
1835 	blk_cleanup_queue(floppy_queue);
1836 	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1837 	unregister_blkdev(FLOPPY_MAJOR, "fd");
1838 }
1839 #endif
1840 
1841 #else
1842 static int __init amiga_floppy_setup (char *str)
1843 {
1844 	int n;
1845 	if (!MACH_IS_AMIGA)
1846 		return 0;
1847 	if (!get_option(&str, &n))
1848 		return 0;
1849 	printk (KERN_INFO "amiflop: Setting default df0 to %x\n", n);
1850 	fd_def_df0 = n;
1851 	return 1;
1852 }
1853 
1854 __setup("floppy=", amiga_floppy_setup);
1855 #endif
1856