xref: /openbmc/linux/drivers/block/amiflop.c (revision 87c2ce3b)
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 
68 #include <asm/setup.h>
69 #include <asm/uaccess.h>
70 #include <asm/amigahw.h>
71 #include <asm/amigaints.h>
72 #include <asm/irq.h>
73 
74 #undef DEBUG /* print _LOTS_ of infos */
75 
76 #define RAW_IOCTL
77 #ifdef RAW_IOCTL
78 #define IOCTL_RAW_TRACK 0x5254524B  /* 'RTRK' */
79 #endif
80 
81 /*
82  *  Defines
83  */
84 
85 /*
86  *  Error codes
87  */
88 #define FD_OK		0	/* operation succeeded */
89 #define FD_ERROR	-1	/* general error (seek, read, write, etc) */
90 #define FD_NOUNIT	1	/* unit does not exist */
91 #define FD_UNITBUSY	2	/* unit already active */
92 #define FD_NOTACTIVE	3	/* unit is not active */
93 #define FD_NOTREADY	4	/* unit is not ready (motor not on/no disk) */
94 
95 #define MFM_NOSYNC	1
96 #define MFM_HEADER	2
97 #define MFM_DATA	3
98 #define MFM_TRACK	4
99 
100 /*
101  *  Floppy ID values
102  */
103 #define FD_NODRIVE	0x00000000  /* response when no unit is present */
104 #define FD_DD_3 	0xffffffff  /* double-density 3.5" (880K) drive */
105 #define FD_HD_3 	0x55555555  /* high-density 3.5" (1760K) drive */
106 #define FD_DD_5 	0xaaaaaaaa  /* double-density 5.25" (440K) drive */
107 
108 static unsigned long int fd_def_df0 = FD_DD_3;     /* default for df0 if it doesn't identify */
109 
110 module_param(fd_def_df0, ulong, 0);
111 MODULE_LICENSE("GPL");
112 
113 static struct request_queue *floppy_queue;
114 #define QUEUE (floppy_queue)
115 #define CURRENT elv_next_request(floppy_queue)
116 
117 /*
118  *  Macros
119  */
120 #define MOTOR_ON	(ciab.prb &= ~DSKMOTOR)
121 #define MOTOR_OFF	(ciab.prb |= DSKMOTOR)
122 #define SELECT(mask)    (ciab.prb &= ~mask)
123 #define DESELECT(mask)  (ciab.prb |= mask)
124 #define SELMASK(drive)  (1 << (3 + (drive & 3)))
125 
126 static struct fd_drive_type drive_types[] = {
127 /*  code	name	   tr he   rdsz   wrsz sm pc1 pc2 sd  st st*/
128 /*  warning: times are now in milliseconds (ms)                    */
129 { FD_DD_3,	"DD 3.5",  80, 2, 14716, 13630, 1, 80,161, 3, 18, 1},
130 { FD_HD_3,	"HD 3.5",  80, 2, 28344, 27258, 2, 80,161, 3, 18, 1},
131 { FD_DD_5,	"DD 5.25", 40, 2, 14716, 13630, 1, 40, 81, 6, 30, 2},
132 { FD_NODRIVE, "No Drive", 0, 0,     0,     0, 0,  0,  0,  0,  0, 0}
133 };
134 static int num_dr_types = ARRAY_SIZE(drive_types);
135 
136 static int amiga_read(int), dos_read(int);
137 static void amiga_write(int), dos_write(int);
138 static struct fd_data_type data_types[] = {
139 	{ "Amiga", 11 , amiga_read, amiga_write},
140 	{ "MS-Dos", 9, dos_read, dos_write}
141 };
142 
143 /* current info on each unit */
144 static struct amiga_floppy_struct unit[FD_MAX_UNITS];
145 
146 static struct timer_list flush_track_timer[FD_MAX_UNITS];
147 static struct timer_list post_write_timer;
148 static struct timer_list motor_on_timer;
149 static struct timer_list motor_off_timer[FD_MAX_UNITS];
150 static int on_attempts;
151 
152 /* Synchronization of FDC access */
153 /* request loop (trackbuffer) */
154 static volatile int fdc_busy = -1;
155 static volatile int fdc_nested;
156 static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
157 
158 static DECLARE_WAIT_QUEUE_HEAD(motor_wait);
159 
160 static volatile int selected = -1;	/* currently selected drive */
161 
162 static int writepending;
163 static int writefromint;
164 static char *raw_buf;
165 
166 static DEFINE_SPINLOCK(amiflop_lock);
167 
168 #define RAW_BUF_SIZE 30000  /* size of raw disk data */
169 
170 /*
171  * These are global variables, as that's the easiest way to give
172  * information to interrupts. They are the data used for the current
173  * request.
174  */
175 static volatile char block_flag;
176 static DECLARE_WAIT_QUEUE_HEAD(wait_fd_block);
177 
178 /* MS-Dos MFM Coding tables (should go quick and easy) */
179 static unsigned char mfmencode[16]={
180 	0x2a, 0x29, 0x24, 0x25, 0x12, 0x11, 0x14, 0x15,
181 	0x4a, 0x49, 0x44, 0x45, 0x52, 0x51, 0x54, 0x55
182 };
183 static unsigned char mfmdecode[128];
184 
185 /* floppy internal millisecond timer stuff */
186 static volatile int ms_busy = -1;
187 static DECLARE_WAIT_QUEUE_HEAD(ms_wait);
188 #define MS_TICKS ((amiga_eclock+50)/1000)
189 
190 /*
191  * Note that MAX_ERRORS=X doesn't imply that we retry every bad read
192  * max X times - some types of errors increase the errorcount by 2 or
193  * even 3, so we might actually retry only X/2 times before giving up.
194  */
195 #define MAX_ERRORS 12
196 
197 /* Prevent "aliased" accesses. */
198 static int fd_ref[4] = { 0,0,0,0 };
199 static int fd_device[4] = { 0, 0, 0, 0 };
200 
201 /*
202  * Here come the actual hardware access and helper functions.
203  * They are not reentrant and single threaded because all drives
204  * share the same hardware and the same trackbuffer.
205  */
206 
207 /* Milliseconds timer */
208 
209 static irqreturn_t ms_isr(int irq, void *dummy, struct pt_regs *fp)
210 {
211 	ms_busy = -1;
212 	wake_up(&ms_wait);
213 	return IRQ_HANDLED;
214 }
215 
216 /* all waits are queued up
217    A more generic routine would do a schedule a la timer.device */
218 static void ms_delay(int ms)
219 {
220 	unsigned long flags;
221 	int ticks;
222 	if (ms > 0) {
223 		local_irq_save(flags);
224 		while (ms_busy == 0)
225 			sleep_on(&ms_wait);
226 		ms_busy = 0;
227 		local_irq_restore(flags);
228 		ticks = MS_TICKS*ms-1;
229 		ciaa.tblo=ticks%256;
230 		ciaa.tbhi=ticks/256;
231 		ciaa.crb=0x19; /*count eclock, force load, one-shoot, start */
232 		sleep_on(&ms_wait);
233 	}
234 }
235 
236 /* Hardware semaphore */
237 
238 /* returns true when we would get the semaphore */
239 static inline int try_fdc(int drive)
240 {
241 	drive &= 3;
242 	return ((fdc_busy < 0) || (fdc_busy == drive));
243 }
244 
245 static void get_fdc(int drive)
246 {
247 	unsigned long flags;
248 
249 	drive &= 3;
250 #ifdef DEBUG
251 	printk("get_fdc: drive %d  fdc_busy %d  fdc_nested %d\n",drive,fdc_busy,fdc_nested);
252 #endif
253 	local_irq_save(flags);
254 	while (!try_fdc(drive))
255 		sleep_on(&fdc_wait);
256 	fdc_busy = drive;
257 	fdc_nested++;
258 	local_irq_restore(flags);
259 }
260 
261 static inline void rel_fdc(void)
262 {
263 #ifdef DEBUG
264 	if (fdc_nested == 0)
265 		printk("fd: unmatched rel_fdc\n");
266 	printk("rel_fdc: fdc_busy %d fdc_nested %d\n",fdc_busy,fdc_nested);
267 #endif
268 	fdc_nested--;
269 	if (fdc_nested == 0) {
270 		fdc_busy = -1;
271 		wake_up(&fdc_wait);
272 	}
273 }
274 
275 static void fd_select (int drive)
276 {
277 	unsigned char prb = ~0;
278 
279 	drive&=3;
280 #ifdef DEBUG
281 	printk("selecting %d\n",drive);
282 #endif
283 	if (drive == selected)
284 		return;
285 	get_fdc(drive);
286 	selected = drive;
287 
288 	if (unit[drive].track % 2 != 0)
289 		prb &= ~DSKSIDE;
290 	if (unit[drive].motor == 1)
291 		prb &= ~DSKMOTOR;
292 	ciab.prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
293 	ciab.prb = prb;
294 	prb &= ~SELMASK(drive);
295 	ciab.prb = prb;
296 	rel_fdc();
297 }
298 
299 static void fd_deselect (int drive)
300 {
301 	unsigned char prb;
302 	unsigned long flags;
303 
304 	drive&=3;
305 #ifdef DEBUG
306 	printk("deselecting %d\n",drive);
307 #endif
308 	if (drive != selected) {
309 		printk(KERN_WARNING "Deselecting drive %d while %d was selected!\n",drive,selected);
310 		return;
311 	}
312 
313 	get_fdc(drive);
314 	local_irq_save(flags);
315 
316 	selected = -1;
317 
318 	prb = ciab.prb;
319 	prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
320 	ciab.prb = prb;
321 
322 	local_irq_restore (flags);
323 	rel_fdc();
324 
325 }
326 
327 static void motor_on_callback(unsigned long nr)
328 {
329 	if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
330 		wake_up (&motor_wait);
331 	} else {
332 		motor_on_timer.expires = jiffies + HZ/10;
333 		add_timer(&motor_on_timer);
334 	}
335 }
336 
337 static int fd_motor_on(int nr)
338 {
339 	nr &= 3;
340 
341 	del_timer(motor_off_timer + nr);
342 
343 	if (!unit[nr].motor) {
344 		unit[nr].motor = 1;
345 		fd_select(nr);
346 
347 		motor_on_timer.data = nr;
348 		mod_timer(&motor_on_timer, jiffies + HZ/2);
349 
350 		on_attempts = 10;
351 		sleep_on (&motor_wait);
352 		fd_deselect(nr);
353 	}
354 
355 	if (on_attempts == 0) {
356 		on_attempts = -1;
357 #if 0
358 		printk (KERN_ERR "motor_on failed, turning motor off\n");
359 		fd_motor_off (nr);
360 		return 0;
361 #else
362 		printk (KERN_WARNING "DSKRDY not set after 1.5 seconds - assuming drive is spinning notwithstanding\n");
363 #endif
364 	}
365 
366 	return 1;
367 }
368 
369 static void fd_motor_off(unsigned long drive)
370 {
371 	long calledfromint;
372 #ifdef MODULE
373 	long decusecount;
374 
375 	decusecount = drive & 0x40000000;
376 #endif
377 	calledfromint = drive & 0x80000000;
378 	drive&=3;
379 	if (calledfromint && !try_fdc(drive)) {
380 		/* We would be blocked in an interrupt, so try again later */
381 		motor_off_timer[drive].expires = jiffies + 1;
382 		add_timer(motor_off_timer + drive);
383 		return;
384 	}
385 	unit[drive].motor = 0;
386 	fd_select(drive);
387 	udelay (1);
388 	fd_deselect(drive);
389 }
390 
391 static void floppy_off (unsigned int nr)
392 {
393 	int drive;
394 
395 	drive = nr & 3;
396 	/* called this way it is always from interrupt */
397 	motor_off_timer[drive].data = nr | 0x80000000;
398 	mod_timer(motor_off_timer + drive, jiffies + 3*HZ);
399 }
400 
401 static int fd_calibrate(int drive)
402 {
403 	unsigned char prb;
404 	int n;
405 
406 	drive &= 3;
407 	get_fdc(drive);
408 	if (!fd_motor_on (drive))
409 		return 0;
410 	fd_select (drive);
411 	prb = ciab.prb;
412 	prb |= DSKSIDE;
413 	prb &= ~DSKDIREC;
414 	ciab.prb = prb;
415 	for (n = unit[drive].type->tracks/2; n != 0; --n) {
416 		if (ciaa.pra & DSKTRACK0)
417 			break;
418 		prb &= ~DSKSTEP;
419 		ciab.prb = prb;
420 		prb |= DSKSTEP;
421 		udelay (2);
422 		ciab.prb = prb;
423 		ms_delay(unit[drive].type->step_delay);
424 	}
425 	ms_delay (unit[drive].type->settle_time);
426 	prb |= DSKDIREC;
427 	n = unit[drive].type->tracks + 20;
428 	for (;;) {
429 		prb &= ~DSKSTEP;
430 		ciab.prb = prb;
431 		prb |= DSKSTEP;
432 		udelay (2);
433 		ciab.prb = prb;
434 		ms_delay(unit[drive].type->step_delay + 1);
435 		if ((ciaa.pra & DSKTRACK0) == 0)
436 			break;
437 		if (--n == 0) {
438 			printk (KERN_ERR "fd%d: calibrate failed, turning motor off\n", drive);
439 			fd_motor_off (drive);
440 			unit[drive].track = -1;
441 			rel_fdc();
442 			return 0;
443 		}
444 	}
445 	unit[drive].track = 0;
446 	ms_delay(unit[drive].type->settle_time);
447 
448 	rel_fdc();
449 	fd_deselect(drive);
450 	return 1;
451 }
452 
453 static int fd_seek(int drive, int track)
454 {
455 	unsigned char prb;
456 	int cnt;
457 
458 #ifdef DEBUG
459 	printk("seeking drive %d to track %d\n",drive,track);
460 #endif
461 	drive &= 3;
462 	get_fdc(drive);
463 	if (unit[drive].track == track) {
464 		rel_fdc();
465 		return 1;
466 	}
467 	if (!fd_motor_on(drive)) {
468 		rel_fdc();
469 		return 0;
470 	}
471 	if (unit[drive].track < 0 && !fd_calibrate(drive)) {
472 		rel_fdc();
473 		return 0;
474 	}
475 
476 	fd_select (drive);
477 	cnt = unit[drive].track/2 - track/2;
478 	prb = ciab.prb;
479 	prb |= DSKSIDE | DSKDIREC;
480 	if (track % 2 != 0)
481 		prb &= ~DSKSIDE;
482 	if (cnt < 0) {
483 		cnt = - cnt;
484 		prb &= ~DSKDIREC;
485 	}
486 	ciab.prb = prb;
487 	if (track % 2 != unit[drive].track % 2)
488 		ms_delay (unit[drive].type->side_time);
489 	unit[drive].track = track;
490 	if (cnt == 0) {
491 		rel_fdc();
492 		fd_deselect(drive);
493 		return 1;
494 	}
495 	do {
496 		prb &= ~DSKSTEP;
497 		ciab.prb = prb;
498 		prb |= DSKSTEP;
499 		udelay (1);
500 		ciab.prb = prb;
501 		ms_delay (unit[drive].type->step_delay);
502 	} while (--cnt != 0);
503 	ms_delay (unit[drive].type->settle_time);
504 
505 	rel_fdc();
506 	fd_deselect(drive);
507 	return 1;
508 }
509 
510 static unsigned long fd_get_drive_id(int drive)
511 {
512 	int i;
513 	ulong id = 0;
514 
515   	drive&=3;
516   	get_fdc(drive);
517 	/* set up for ID */
518 	MOTOR_ON;
519 	udelay(2);
520 	SELECT(SELMASK(drive));
521 	udelay(2);
522 	DESELECT(SELMASK(drive));
523 	udelay(2);
524 	MOTOR_OFF;
525 	udelay(2);
526 	SELECT(SELMASK(drive));
527 	udelay(2);
528 	DESELECT(SELMASK(drive));
529 	udelay(2);
530 
531 	/* loop and read disk ID */
532 	for (i=0; i<32; i++) {
533 		SELECT(SELMASK(drive));
534 		udelay(2);
535 
536 		/* read and store value of DSKRDY */
537 		id <<= 1;
538 		id |= (ciaa.pra & DSKRDY) ? 0 : 1;	/* cia regs are low-active! */
539 
540 		DESELECT(SELMASK(drive));
541 	}
542 
543 	rel_fdc();
544 
545         /*
546          * RB: At least A500/A2000's df0: don't identify themselves.
547          * As every (real) Amiga has at least a 3.5" DD drive as df0:
548          * we default to that if df0: doesn't identify as a certain
549          * type.
550          */
551         if(drive == 0 && id == FD_NODRIVE)
552 	{
553                 id = fd_def_df0;
554                 printk(KERN_NOTICE "fd: drive 0 didn't identify, setting default %08lx\n", (ulong)fd_def_df0);
555 	}
556 	/* return the ID value */
557 	return (id);
558 }
559 
560 static irqreturn_t fd_block_done(int irq, void *dummy, struct pt_regs *fp)
561 {
562 	if (block_flag)
563 		custom.dsklen = 0x4000;
564 
565 	if (block_flag == 2) { /* writing */
566 		writepending = 2;
567 		post_write_timer.expires = jiffies + 1; /* at least 2 ms */
568 		post_write_timer.data = selected;
569 		add_timer(&post_write_timer);
570 	}
571 	else {                /* reading */
572 		block_flag = 0;
573 		wake_up (&wait_fd_block);
574 	}
575 	return IRQ_HANDLED;
576 }
577 
578 static void raw_read(int drive)
579 {
580 	drive&=3;
581 	get_fdc(drive);
582 	while (block_flag)
583 		sleep_on(&wait_fd_block);
584 	fd_select(drive);
585 	/* setup adkcon bits correctly */
586 	custom.adkcon = ADK_MSBSYNC;
587 	custom.adkcon = ADK_SETCLR|ADK_WORDSYNC|ADK_FAST;
588 
589 	custom.dsksync = MFM_SYNC;
590 
591 	custom.dsklen = 0;
592 	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
593 	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
594 	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
595 
596 	block_flag = 1;
597 
598 	while (block_flag)
599 		sleep_on (&wait_fd_block);
600 
601 	custom.dsklen = 0;
602 	fd_deselect(drive);
603 	rel_fdc();
604 }
605 
606 static int raw_write(int drive)
607 {
608 	ushort adk;
609 
610 	drive&=3;
611 	get_fdc(drive); /* corresponds to rel_fdc() in post_write() */
612 	if ((ciaa.pra & DSKPROT) == 0) {
613 		rel_fdc();
614 		return 0;
615 	}
616 	while (block_flag)
617 		sleep_on(&wait_fd_block);
618 	fd_select(drive);
619 	/* clear adkcon bits */
620 	custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
621 	/* set appropriate adkcon bits */
622 	adk = ADK_SETCLR|ADK_FAST;
623 	if ((ulong)unit[drive].track >= unit[drive].type->precomp2)
624 		adk |= ADK_PRECOMP1;
625 	else if ((ulong)unit[drive].track >= unit[drive].type->precomp1)
626 		adk |= ADK_PRECOMP0;
627 	custom.adkcon = adk;
628 
629 	custom.dsklen = DSKLEN_WRITE;
630 	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
631 	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
632 	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
633 
634 	block_flag = 2;
635 	return 1;
636 }
637 
638 /*
639  * to be called at least 2ms after the write has finished but before any
640  * other access to the hardware.
641  */
642 static void post_write (unsigned long drive)
643 {
644 #ifdef DEBUG
645 	printk("post_write for drive %ld\n",drive);
646 #endif
647 	drive &= 3;
648 	custom.dsklen = 0;
649 	block_flag = 0;
650 	writepending = 0;
651 	writefromint = 0;
652 	unit[drive].dirty = 0;
653 	wake_up(&wait_fd_block);
654 	fd_deselect(drive);
655 	rel_fdc(); /* corresponds to get_fdc() in raw_write */
656 }
657 
658 
659 /*
660  * The following functions are to convert the block contents into raw data
661  * written to disk and vice versa.
662  * (Add other formats here ;-))
663  */
664 
665 static unsigned long scan_sync(unsigned long raw, unsigned long end)
666 {
667 	ushort *ptr = (ushort *)raw, *endp = (ushort *)end;
668 
669 	while (ptr < endp && *ptr++ != 0x4489)
670 		;
671 	if (ptr < endp) {
672 		while (*ptr == 0x4489 && ptr < endp)
673 			ptr++;
674 		return (ulong)ptr;
675 	}
676 	return 0;
677 }
678 
679 static inline unsigned long checksum(unsigned long *addr, int len)
680 {
681 	unsigned long csum = 0;
682 
683 	len /= sizeof(*addr);
684 	while (len-- > 0)
685 		csum ^= *addr++;
686 	csum = ((csum>>1) & 0x55555555)  ^  (csum & 0x55555555);
687 
688 	return csum;
689 }
690 
691 static unsigned long decode (unsigned long *data, unsigned long *raw,
692 			     int len)
693 {
694 	ulong *odd, *even;
695 
696 	/* convert length from bytes to longwords */
697 	len >>= 2;
698 	odd = raw;
699 	even = odd + len;
700 
701 	/* prepare return pointer */
702 	raw += len * 2;
703 
704 	do {
705 		*data++ = ((*odd++ & 0x55555555) << 1) | (*even++ & 0x55555555);
706 	} while (--len != 0);
707 
708 	return (ulong)raw;
709 }
710 
711 struct header {
712 	unsigned char magic;
713 	unsigned char track;
714 	unsigned char sect;
715 	unsigned char ord;
716 	unsigned char labels[16];
717 	unsigned long hdrchk;
718 	unsigned long datachk;
719 };
720 
721 static int amiga_read(int drive)
722 {
723 	unsigned long raw;
724 	unsigned long end;
725 	int scnt;
726 	unsigned long csum;
727 	struct header hdr;
728 
729 	drive&=3;
730 	raw = (long) raw_buf;
731 	end = raw + unit[drive].type->read_size;
732 
733 	for (scnt = 0;scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
734 		if (!(raw = scan_sync(raw, end))) {
735 			printk (KERN_INFO "can't find sync for sector %d\n", scnt);
736 			return MFM_NOSYNC;
737 		}
738 
739 		raw = decode ((ulong *)&hdr.magic, (ulong *)raw, 4);
740 		raw = decode ((ulong *)&hdr.labels, (ulong *)raw, 16);
741 		raw = decode ((ulong *)&hdr.hdrchk, (ulong *)raw, 4);
742 		raw = decode ((ulong *)&hdr.datachk, (ulong *)raw, 4);
743 		csum = checksum((ulong *)&hdr,
744 				(char *)&hdr.hdrchk-(char *)&hdr);
745 
746 #ifdef DEBUG
747 		printk ("(%x,%d,%d,%d) (%lx,%lx,%lx,%lx) %lx %lx\n",
748 			hdr.magic, hdr.track, hdr.sect, hdr.ord,
749 			*(ulong *)&hdr.labels[0], *(ulong *)&hdr.labels[4],
750 			*(ulong *)&hdr.labels[8], *(ulong *)&hdr.labels[12],
751 			hdr.hdrchk, hdr.datachk);
752 #endif
753 
754 		if (hdr.hdrchk != csum) {
755 			printk(KERN_INFO "MFM_HEADER: %08lx,%08lx\n", hdr.hdrchk, csum);
756 			return MFM_HEADER;
757 		}
758 
759 		/* verify track */
760 		if (hdr.track != unit[drive].track) {
761 			printk(KERN_INFO "MFM_TRACK: %d, %d\n", hdr.track, unit[drive].track);
762 			return MFM_TRACK;
763 		}
764 
765 		raw = decode ((ulong *)(unit[drive].trackbuf + hdr.sect*512),
766 			      (ulong *)raw, 512);
767 		csum = checksum((ulong *)(unit[drive].trackbuf + hdr.sect*512), 512);
768 
769 		if (hdr.datachk != csum) {
770 			printk(KERN_INFO "MFM_DATA: (%x:%d:%d:%d) sc=%d %lx, %lx\n",
771 			       hdr.magic, hdr.track, hdr.sect, hdr.ord, scnt,
772 			       hdr.datachk, csum);
773 			printk (KERN_INFO "data=(%lx,%lx,%lx,%lx)\n",
774 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[0],
775 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[1],
776 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[2],
777 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[3]);
778 			return MFM_DATA;
779 		}
780 	}
781 
782 	return 0;
783 }
784 
785 static void encode(unsigned long data, unsigned long *dest)
786 {
787 	unsigned long data2;
788 
789 	data &= 0x55555555;
790 	data2 = data ^ 0x55555555;
791 	data |= ((data2 >> 1) | 0x80000000) & (data2 << 1);
792 
793 	if (*(dest - 1) & 0x00000001)
794 		data &= 0x7FFFFFFF;
795 
796 	*dest = data;
797 }
798 
799 static void encode_block(unsigned long *dest, unsigned long *src, int len)
800 {
801 	int cnt, to_cnt = 0;
802 	unsigned long data;
803 
804 	/* odd bits */
805 	for (cnt = 0; cnt < len / 4; cnt++) {
806 		data = src[cnt] >> 1;
807 		encode(data, dest + to_cnt++);
808 	}
809 
810 	/* even bits */
811 	for (cnt = 0; cnt < len / 4; cnt++) {
812 		data = src[cnt];
813 		encode(data, dest + to_cnt++);
814 	}
815 }
816 
817 static unsigned long *putsec(int disk, unsigned long *raw, int cnt)
818 {
819 	struct header hdr;
820 	int i;
821 
822 	disk&=3;
823 	*raw = (raw[-1]&1) ? 0x2AAAAAAA : 0xAAAAAAAA;
824 	raw++;
825 	*raw++ = 0x44894489;
826 
827 	hdr.magic = 0xFF;
828 	hdr.track = unit[disk].track;
829 	hdr.sect = cnt;
830 	hdr.ord = unit[disk].dtype->sects * unit[disk].type->sect_mult - cnt;
831 	for (i = 0; i < 16; i++)
832 		hdr.labels[i] = 0;
833 	hdr.hdrchk = checksum((ulong *)&hdr,
834 			      (char *)&hdr.hdrchk-(char *)&hdr);
835 	hdr.datachk = checksum((ulong *)(unit[disk].trackbuf+cnt*512), 512);
836 
837 	encode_block(raw, (ulong *)&hdr.magic, 4);
838 	raw += 2;
839 	encode_block(raw, (ulong *)&hdr.labels, 16);
840 	raw += 8;
841 	encode_block(raw, (ulong *)&hdr.hdrchk, 4);
842 	raw += 2;
843 	encode_block(raw, (ulong *)&hdr.datachk, 4);
844 	raw += 2;
845 	encode_block(raw, (ulong *)(unit[disk].trackbuf+cnt*512), 512);
846 	raw += 256;
847 
848 	return raw;
849 }
850 
851 static void amiga_write(int disk)
852 {
853 	unsigned int cnt;
854 	unsigned long *ptr = (unsigned long *)raw_buf;
855 
856 	disk&=3;
857 	/* gap space */
858 	for (cnt = 0; cnt < 415 * unit[disk].type->sect_mult; cnt++)
859 		*ptr++ = 0xaaaaaaaa;
860 
861 	/* sectors */
862 	for (cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
863 		ptr = putsec (disk, ptr, cnt);
864 	*(ushort *)ptr = (ptr[-1]&1) ? 0x2AA8 : 0xAAA8;
865 }
866 
867 
868 struct dos_header {
869 	unsigned char track,   /* 0-80 */
870 		side,    /* 0-1 */
871 		sec,     /* 0-...*/
872 		len_desc;/* 2 */
873 	unsigned short crc;     /* on 68000 we got an alignment problem,
874 				   but this compiler solves it  by adding silently
875 				   adding a pad byte so data won't fit
876 				   and this took about 3h to discover.... */
877 	unsigned char gap1[22];     /* for longword-alignedness (0x4e) */
878 };
879 
880 /* crc routines are borrowed from the messydos-handler  */
881 
882 /* excerpt from the messydos-device
883 ; The CRC is computed not only over the actual data, but including
884 ; the SYNC mark (3 * $a1) and the 'ID/DATA - Address Mark' ($fe/$fb).
885 ; As we don't read or encode these fields into our buffers, we have to
886 ; preload the registers containing the CRC with the values they would have
887 ; after stepping over these fields.
888 ;
889 ; How CRCs "really" work:
890 ;
891 ; First, you should regard a bitstring as a series of coefficients of
892 ; polynomials. We calculate with these polynomials in modulo-2
893 ; arithmetic, in which both add and subtract are done the same as
894 ; exclusive-or. Now, we modify our data (a very long polynomial) in
895 ; such a way that it becomes divisible by the CCITT-standard 16-bit
896 ;		 16   12   5
897 ; polynomial:	x  + x	+ x + 1, represented by $11021. The easiest
898 ; way to do this would be to multiply (using proper arithmetic) our
899 ; datablock with $11021. So we have:
900 ;   data * $11021		 =
901 ;   data * ($10000 + $1021)      =
902 ;   data * $10000 + data * $1021
903 ; The left part of this is simple: Just add two 0 bytes. But then
904 ; the right part (data $1021) remains difficult and even could have
905 ; a carry into the left part. The solution is to use a modified
906 ; multiplication, which has a result that is not correct, but with
907 ; a difference of any multiple of $11021. We then only need to keep
908 ; the 16 least significant bits of the result.
909 ;
910 ; The following algorithm does this for us:
911 ;
912 ;   unsigned char *data, c, crclo, crchi;
913 ;   while (not done) {
914 ;	c = *data++ + crchi;
915 ;	crchi = (@ c) >> 8 + crclo;
916 ;	crclo = @ c;
917 ;   }
918 ;
919 ; Remember, + is done with EOR, the @ operator is in two tables (high
920 ; and low byte separately), which is calculated as
921 ;
922 ;      $1021 * (c & $F0)
923 ;  xor $1021 * (c & $0F)
924 ;  xor $1021 * (c >> 4)         (* is regular multiplication)
925 ;
926 ;
927 ; Anyway, the end result is the same as the remainder of the division of
928 ; the data by $11021. I am afraid I need to study theory a bit more...
929 
930 
931 my only works was to code this from manx to C....
932 
933 */
934 
935 static ushort dos_crc(void * data_a3, int data_d0, int data_d1, int data_d3)
936 {
937 	static unsigned char CRCTable1[] = {
938 		0x00,0x10,0x20,0x30,0x40,0x50,0x60,0x70,0x81,0x91,0xa1,0xb1,0xc1,0xd1,0xe1,0xf1,
939 		0x12,0x02,0x32,0x22,0x52,0x42,0x72,0x62,0x93,0x83,0xb3,0xa3,0xd3,0xc3,0xf3,0xe3,
940 		0x24,0x34,0x04,0x14,0x64,0x74,0x44,0x54,0xa5,0xb5,0x85,0x95,0xe5,0xf5,0xc5,0xd5,
941 		0x36,0x26,0x16,0x06,0x76,0x66,0x56,0x46,0xb7,0xa7,0x97,0x87,0xf7,0xe7,0xd7,0xc7,
942 		0x48,0x58,0x68,0x78,0x08,0x18,0x28,0x38,0xc9,0xd9,0xe9,0xf9,0x89,0x99,0xa9,0xb9,
943 		0x5a,0x4a,0x7a,0x6a,0x1a,0x0a,0x3a,0x2a,0xdb,0xcb,0xfb,0xeb,0x9b,0x8b,0xbb,0xab,
944 		0x6c,0x7c,0x4c,0x5c,0x2c,0x3c,0x0c,0x1c,0xed,0xfd,0xcd,0xdd,0xad,0xbd,0x8d,0x9d,
945 		0x7e,0x6e,0x5e,0x4e,0x3e,0x2e,0x1e,0x0e,0xff,0xef,0xdf,0xcf,0xbf,0xaf,0x9f,0x8f,
946 		0x91,0x81,0xb1,0xa1,0xd1,0xc1,0xf1,0xe1,0x10,0x00,0x30,0x20,0x50,0x40,0x70,0x60,
947 		0x83,0x93,0xa3,0xb3,0xc3,0xd3,0xe3,0xf3,0x02,0x12,0x22,0x32,0x42,0x52,0x62,0x72,
948 		0xb5,0xa5,0x95,0x85,0xf5,0xe5,0xd5,0xc5,0x34,0x24,0x14,0x04,0x74,0x64,0x54,0x44,
949 		0xa7,0xb7,0x87,0x97,0xe7,0xf7,0xc7,0xd7,0x26,0x36,0x06,0x16,0x66,0x76,0x46,0x56,
950 		0xd9,0xc9,0xf9,0xe9,0x99,0x89,0xb9,0xa9,0x58,0x48,0x78,0x68,0x18,0x08,0x38,0x28,
951 		0xcb,0xdb,0xeb,0xfb,0x8b,0x9b,0xab,0xbb,0x4a,0x5a,0x6a,0x7a,0x0a,0x1a,0x2a,0x3a,
952 		0xfd,0xed,0xdd,0xcd,0xbd,0xad,0x9d,0x8d,0x7c,0x6c,0x5c,0x4c,0x3c,0x2c,0x1c,0x0c,
953 		0xef,0xff,0xcf,0xdf,0xaf,0xbf,0x8f,0x9f,0x6e,0x7e,0x4e,0x5e,0x2e,0x3e,0x0e,0x1e
954 	};
955 
956 	static unsigned char CRCTable2[] = {
957 		0x00,0x21,0x42,0x63,0x84,0xa5,0xc6,0xe7,0x08,0x29,0x4a,0x6b,0x8c,0xad,0xce,0xef,
958 		0x31,0x10,0x73,0x52,0xb5,0x94,0xf7,0xd6,0x39,0x18,0x7b,0x5a,0xbd,0x9c,0xff,0xde,
959 		0x62,0x43,0x20,0x01,0xe6,0xc7,0xa4,0x85,0x6a,0x4b,0x28,0x09,0xee,0xcf,0xac,0x8d,
960 		0x53,0x72,0x11,0x30,0xd7,0xf6,0x95,0xb4,0x5b,0x7a,0x19,0x38,0xdf,0xfe,0x9d,0xbc,
961 		0xc4,0xe5,0x86,0xa7,0x40,0x61,0x02,0x23,0xcc,0xed,0x8e,0xaf,0x48,0x69,0x0a,0x2b,
962 		0xf5,0xd4,0xb7,0x96,0x71,0x50,0x33,0x12,0xfd,0xdc,0xbf,0x9e,0x79,0x58,0x3b,0x1a,
963 		0xa6,0x87,0xe4,0xc5,0x22,0x03,0x60,0x41,0xae,0x8f,0xec,0xcd,0x2a,0x0b,0x68,0x49,
964 		0x97,0xb6,0xd5,0xf4,0x13,0x32,0x51,0x70,0x9f,0xbe,0xdd,0xfc,0x1b,0x3a,0x59,0x78,
965 		0x88,0xa9,0xca,0xeb,0x0c,0x2d,0x4e,0x6f,0x80,0xa1,0xc2,0xe3,0x04,0x25,0x46,0x67,
966 		0xb9,0x98,0xfb,0xda,0x3d,0x1c,0x7f,0x5e,0xb1,0x90,0xf3,0xd2,0x35,0x14,0x77,0x56,
967 		0xea,0xcb,0xa8,0x89,0x6e,0x4f,0x2c,0x0d,0xe2,0xc3,0xa0,0x81,0x66,0x47,0x24,0x05,
968 		0xdb,0xfa,0x99,0xb8,0x5f,0x7e,0x1d,0x3c,0xd3,0xf2,0x91,0xb0,0x57,0x76,0x15,0x34,
969 		0x4c,0x6d,0x0e,0x2f,0xc8,0xe9,0x8a,0xab,0x44,0x65,0x06,0x27,0xc0,0xe1,0x82,0xa3,
970 		0x7d,0x5c,0x3f,0x1e,0xf9,0xd8,0xbb,0x9a,0x75,0x54,0x37,0x16,0xf1,0xd0,0xb3,0x92,
971 		0x2e,0x0f,0x6c,0x4d,0xaa,0x8b,0xe8,0xc9,0x26,0x07,0x64,0x45,0xa2,0x83,0xe0,0xc1,
972 		0x1f,0x3e,0x5d,0x7c,0x9b,0xba,0xd9,0xf8,0x17,0x36,0x55,0x74,0x93,0xb2,0xd1,0xf0
973 	};
974 
975 /* look at the asm-code - what looks in C a bit strange is almost as good as handmade */
976 	register int i;
977 	register unsigned char *CRCT1, *CRCT2, *data, c, crch, crcl;
978 
979 	CRCT1=CRCTable1;
980 	CRCT2=CRCTable2;
981 	data=data_a3;
982 	crcl=data_d1;
983 	crch=data_d0;
984 	for (i=data_d3; i>=0; i--) {
985 		c = (*data++) ^ crch;
986 		crch = CRCT1[c] ^ crcl;
987 		crcl = CRCT2[c];
988 	}
989 	return (crch<<8)|crcl;
990 }
991 
992 static inline ushort dos_hdr_crc (struct dos_header *hdr)
993 {
994 	return dos_crc(&(hdr->track), 0xb2, 0x30, 3); /* precomputed magic */
995 }
996 
997 static inline ushort dos_data_crc(unsigned char *data)
998 {
999 	return dos_crc(data, 0xe2, 0x95 ,511); /* precomputed magic */
1000 }
1001 
1002 static inline unsigned char dos_decode_byte(ushort word)
1003 {
1004 	register ushort w2;
1005 	register unsigned char byte;
1006 	register unsigned char *dec = mfmdecode;
1007 
1008 	w2=word;
1009 	w2>>=8;
1010 	w2&=127;
1011 	byte = dec[w2];
1012 	byte <<= 4;
1013 	w2 = word & 127;
1014 	byte |= dec[w2];
1015 	return byte;
1016 }
1017 
1018 static unsigned long dos_decode(unsigned char *data, unsigned short *raw, int len)
1019 {
1020 	int i;
1021 
1022 	for (i = 0; i < len; i++)
1023 		*data++=dos_decode_byte(*raw++);
1024 	return ((ulong)raw);
1025 }
1026 
1027 #ifdef DEBUG
1028 static void dbg(unsigned long ptr)
1029 {
1030 	printk("raw data @%08lx: %08lx, %08lx ,%08lx, %08lx\n", ptr,
1031 	       ((ulong *)ptr)[0], ((ulong *)ptr)[1],
1032 	       ((ulong *)ptr)[2], ((ulong *)ptr)[3]);
1033 }
1034 #endif
1035 
1036 static int dos_read(int drive)
1037 {
1038 	unsigned long end;
1039 	unsigned long raw;
1040 	int scnt;
1041 	unsigned short crc,data_crc[2];
1042 	struct dos_header hdr;
1043 
1044 	drive&=3;
1045 	raw = (long) raw_buf;
1046 	end = raw + unit[drive].type->read_size;
1047 
1048 	for (scnt=0; scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
1049 		do { /* search for the right sync of each sec-hdr */
1050 			if (!(raw = scan_sync (raw, end))) {
1051 				printk(KERN_INFO "dos_read: no hdr sync on "
1052 				       "track %d, unit %d for sector %d\n",
1053 				       unit[drive].track,drive,scnt);
1054 				return MFM_NOSYNC;
1055 			}
1056 #ifdef DEBUG
1057 			dbg(raw);
1058 #endif
1059 		} while (*((ushort *)raw)!=0x5554); /* loop usually only once done */
1060 		raw+=2; /* skip over headermark */
1061 		raw = dos_decode((unsigned char *)&hdr,(ushort *) raw,8);
1062 		crc = dos_hdr_crc(&hdr);
1063 
1064 #ifdef DEBUG
1065 		printk("(%3d,%d,%2d,%d) %x\n", hdr.track, hdr.side,
1066 		       hdr.sec, hdr.len_desc, hdr.crc);
1067 #endif
1068 
1069 		if (crc != hdr.crc) {
1070 			printk(KERN_INFO "dos_read: MFM_HEADER %04x,%04x\n",
1071 			       hdr.crc, crc);
1072 			return MFM_HEADER;
1073 		}
1074 		if (hdr.track != unit[drive].track/unit[drive].type->heads) {
1075 			printk(KERN_INFO "dos_read: MFM_TRACK %d, %d\n",
1076 			       hdr.track,
1077 			       unit[drive].track/unit[drive].type->heads);
1078 			return MFM_TRACK;
1079 		}
1080 
1081 		if (hdr.side != unit[drive].track%unit[drive].type->heads) {
1082 			printk(KERN_INFO "dos_read: MFM_SIDE %d, %d\n",
1083 			       hdr.side,
1084 			       unit[drive].track%unit[drive].type->heads);
1085 			return MFM_TRACK;
1086 		}
1087 
1088 		if (hdr.len_desc != 2) {
1089 			printk(KERN_INFO "dos_read: unknown sector len "
1090 			       "descriptor %d\n", hdr.len_desc);
1091 			return MFM_DATA;
1092 		}
1093 #ifdef DEBUG
1094 		printk("hdr accepted\n");
1095 #endif
1096 		if (!(raw = scan_sync (raw, end))) {
1097 			printk(KERN_INFO "dos_read: no data sync on track "
1098 			       "%d, unit %d for sector%d, disk sector %d\n",
1099 			       unit[drive].track, drive, scnt, hdr.sec);
1100 			return MFM_NOSYNC;
1101 		}
1102 #ifdef DEBUG
1103 		dbg(raw);
1104 #endif
1105 
1106 		if (*((ushort *)raw)!=0x5545) {
1107 			printk(KERN_INFO "dos_read: no data mark after "
1108 			       "sync (%d,%d,%d,%d) sc=%d\n",
1109 			       hdr.track,hdr.side,hdr.sec,hdr.len_desc,scnt);
1110 			return MFM_NOSYNC;
1111 		}
1112 
1113 		raw+=2;  /* skip data mark (included in checksum) */
1114 		raw = dos_decode((unsigned char *)(unit[drive].trackbuf + (hdr.sec - 1) * 512), (ushort *) raw, 512);
1115 		raw = dos_decode((unsigned char  *)data_crc,(ushort *) raw,4);
1116 		crc = dos_data_crc(unit[drive].trackbuf + (hdr.sec - 1) * 512);
1117 
1118 		if (crc != data_crc[0]) {
1119 			printk(KERN_INFO "dos_read: MFM_DATA (%d,%d,%d,%d) "
1120 			       "sc=%d, %x %x\n", hdr.track, hdr.side,
1121 			       hdr.sec, hdr.len_desc, scnt,data_crc[0], crc);
1122 			printk(KERN_INFO "data=(%lx,%lx,%lx,%lx,...)\n",
1123 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[0],
1124 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[1],
1125 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[2],
1126 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[3]);
1127 			return MFM_DATA;
1128 		}
1129 	}
1130 	return 0;
1131 }
1132 
1133 static inline ushort dos_encode_byte(unsigned char byte)
1134 {
1135 	register unsigned char *enc, b2, b1;
1136 	register ushort word;
1137 
1138 	enc=mfmencode;
1139 	b1=byte;
1140 	b2=b1>>4;
1141 	b1&=15;
1142 	word=enc[b2] <<8 | enc [b1];
1143 	return (word|((word&(256|64)) ? 0: 128));
1144 }
1145 
1146 static void dos_encode_block(ushort *dest, unsigned char *src, int len)
1147 {
1148 	int i;
1149 
1150 	for (i = 0; i < len; i++) {
1151 		*dest=dos_encode_byte(*src++);
1152 		*dest|=((dest[-1]&1)||(*dest&0x4000))? 0: 0x8000;
1153 		dest++;
1154 	}
1155 }
1156 
1157 static unsigned long *ms_putsec(int drive, unsigned long *raw, int cnt)
1158 {
1159 	static struct dos_header hdr={0,0,0,2,0,
1160 	  {78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78}};
1161 	int i;
1162 	static ushort crc[2]={0,0x4e4e};
1163 
1164 	drive&=3;
1165 /* id gap 1 */
1166 /* the MFM word before is always 9254 */
1167 	for(i=0;i<6;i++)
1168 		*raw++=0xaaaaaaaa;
1169 /* 3 sync + 1 headermark */
1170 	*raw++=0x44894489;
1171 	*raw++=0x44895554;
1172 
1173 /* fill in the variable parts of the header */
1174 	hdr.track=unit[drive].track/unit[drive].type->heads;
1175 	hdr.side=unit[drive].track%unit[drive].type->heads;
1176 	hdr.sec=cnt+1;
1177 	hdr.crc=dos_hdr_crc(&hdr);
1178 
1179 /* header (without "magic") and id gap 2*/
1180 	dos_encode_block((ushort *)raw,(unsigned char *) &hdr.track,28);
1181 	raw+=14;
1182 
1183 /*id gap 3 */
1184 	for(i=0;i<6;i++)
1185 		*raw++=0xaaaaaaaa;
1186 
1187 /* 3 syncs and 1 datamark */
1188 	*raw++=0x44894489;
1189 	*raw++=0x44895545;
1190 
1191 /* data */
1192 	dos_encode_block((ushort *)raw,
1193 			 (unsigned char *)unit[drive].trackbuf+cnt*512,512);
1194 	raw+=256;
1195 
1196 /*data crc + jd's special gap (long words :-/) */
1197 	crc[0]=dos_data_crc(unit[drive].trackbuf+cnt*512);
1198 	dos_encode_block((ushort *) raw,(unsigned char *)crc,4);
1199 	raw+=2;
1200 
1201 /* data gap */
1202 	for(i=0;i<38;i++)
1203 		*raw++=0x92549254;
1204 
1205 	return raw; /* wrote 652 MFM words */
1206 }
1207 
1208 static void dos_write(int disk)
1209 {
1210 	int cnt;
1211 	unsigned long raw = (unsigned long) raw_buf;
1212 	unsigned long *ptr=(unsigned long *)raw;
1213 
1214 	disk&=3;
1215 /* really gap4 + indexgap , but we write it first and round it up */
1216 	for (cnt=0;cnt<425;cnt++)
1217 		*ptr++=0x92549254;
1218 
1219 /* the following is just guessed */
1220 	if (unit[disk].type->sect_mult==2)  /* check for HD-Disks */
1221 		for(cnt=0;cnt<473;cnt++)
1222 			*ptr++=0x92549254;
1223 
1224 /* now the index marks...*/
1225 	for (cnt=0;cnt<20;cnt++)
1226 		*ptr++=0x92549254;
1227 	for (cnt=0;cnt<6;cnt++)
1228 		*ptr++=0xaaaaaaaa;
1229 	*ptr++=0x52245224;
1230 	*ptr++=0x52245552;
1231 	for (cnt=0;cnt<20;cnt++)
1232 		*ptr++=0x92549254;
1233 
1234 /* sectors */
1235 	for(cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
1236 		ptr=ms_putsec(disk,ptr,cnt);
1237 
1238 	*(ushort *)ptr = 0xaaa8; /* MFM word before is always 0x9254 */
1239 }
1240 
1241 /*
1242  * Here comes the high level stuff (i.e. the filesystem interface)
1243  * and helper functions.
1244  * Normally this should be the only part that has to be adapted to
1245  * different kernel versions.
1246  */
1247 
1248 /* FIXME: this assumes the drive is still spinning -
1249  * which is only true if we complete writing a track within three seconds
1250  */
1251 static void flush_track_callback(unsigned long nr)
1252 {
1253 	nr&=3;
1254 	writefromint = 1;
1255 	if (!try_fdc(nr)) {
1256 		/* we might block in an interrupt, so try again later */
1257 		flush_track_timer[nr].expires = jiffies + 1;
1258 		add_timer(flush_track_timer + nr);
1259 		return;
1260 	}
1261 	get_fdc(nr);
1262 	(*unit[nr].dtype->write_fkt)(nr);
1263 	if (!raw_write(nr)) {
1264 		printk (KERN_NOTICE "floppy disk write protected\n");
1265 		writefromint = 0;
1266 		writepending = 0;
1267 	}
1268 	rel_fdc();
1269 }
1270 
1271 static int non_int_flush_track (unsigned long nr)
1272 {
1273 	unsigned long flags;
1274 
1275 	nr&=3;
1276 	writefromint = 0;
1277 	del_timer(&post_write_timer);
1278 	get_fdc(nr);
1279 	if (!fd_motor_on(nr)) {
1280 		writepending = 0;
1281 		rel_fdc();
1282 		return 0;
1283 	}
1284 	local_irq_save(flags);
1285 	if (writepending != 2) {
1286 		local_irq_restore(flags);
1287 		(*unit[nr].dtype->write_fkt)(nr);
1288 		if (!raw_write(nr)) {
1289 			printk (KERN_NOTICE "floppy disk write protected "
1290 				"in write!\n");
1291 			writepending = 0;
1292 			return 0;
1293 		}
1294 		while (block_flag == 2)
1295 			sleep_on (&wait_fd_block);
1296 	}
1297 	else {
1298 		local_irq_restore(flags);
1299 		ms_delay(2); /* 2 ms post_write delay */
1300 		post_write(nr);
1301 	}
1302 	rel_fdc();
1303 	return 1;
1304 }
1305 
1306 static int get_track(int drive, int track)
1307 {
1308 	int error, errcnt;
1309 
1310 	drive&=3;
1311 	if (unit[drive].track == track)
1312 		return 0;
1313 	get_fdc(drive);
1314 	if (!fd_motor_on(drive)) {
1315 		rel_fdc();
1316 		return -1;
1317 	}
1318 
1319 	if (unit[drive].dirty == 1) {
1320 		del_timer (flush_track_timer + drive);
1321 		non_int_flush_track (drive);
1322 	}
1323 	errcnt = 0;
1324 	while (errcnt < MAX_ERRORS) {
1325 		if (!fd_seek(drive, track))
1326 			return -1;
1327 		raw_read(drive);
1328 		error = (*unit[drive].dtype->read_fkt)(drive);
1329 		if (error == 0) {
1330 			rel_fdc();
1331 			return 0;
1332 		}
1333 		/* Read Error Handling: recalibrate and try again */
1334 		unit[drive].track = -1;
1335 		errcnt++;
1336 	}
1337 	rel_fdc();
1338 	return -1;
1339 }
1340 
1341 static void redo_fd_request(void)
1342 {
1343 	unsigned int cnt, block, track, sector;
1344 	int drive;
1345 	struct amiga_floppy_struct *floppy;
1346 	char *data;
1347 	unsigned long flags;
1348 
1349  repeat:
1350 	if (!CURRENT) {
1351 		/* Nothing left to do */
1352 		return;
1353 	}
1354 
1355 	floppy = CURRENT->rq_disk->private_data;
1356 	drive = floppy - unit;
1357 
1358 	/* Here someone could investigate to be more efficient */
1359 	for (cnt = 0; cnt < CURRENT->current_nr_sectors; cnt++) {
1360 #ifdef DEBUG
1361 		printk("fd: sector %ld + %d requested for %s\n",
1362 		       CURRENT->sector,cnt,
1363 		       (CURRENT->cmd==READ)?"read":"write");
1364 #endif
1365 		block = CURRENT->sector + cnt;
1366 		if ((int)block > floppy->blocks) {
1367 			end_request(CURRENT, 0);
1368 			goto repeat;
1369 		}
1370 
1371 		track = block / (floppy->dtype->sects * floppy->type->sect_mult);
1372 		sector = block % (floppy->dtype->sects * floppy->type->sect_mult);
1373 		data = CURRENT->buffer + 512 * cnt;
1374 #ifdef DEBUG
1375 		printk("access to track %d, sector %d, with buffer at "
1376 		       "0x%08lx\n", track, sector, data);
1377 #endif
1378 
1379 		if ((rq_data_dir(CURRENT) != READ) && (rq_data_dir(CURRENT) != WRITE)) {
1380 			printk(KERN_WARNING "do_fd_request: unknown command\n");
1381 			end_request(CURRENT, 0);
1382 			goto repeat;
1383 		}
1384 		if (get_track(drive, track) == -1) {
1385 			end_request(CURRENT, 0);
1386 			goto repeat;
1387 		}
1388 
1389 		switch (rq_data_dir(CURRENT)) {
1390 		case READ:
1391 			memcpy(data, floppy->trackbuf + sector * 512, 512);
1392 			break;
1393 
1394 		case WRITE:
1395 			memcpy(floppy->trackbuf + sector * 512, data, 512);
1396 
1397 			/* keep the drive spinning while writes are scheduled */
1398 			if (!fd_motor_on(drive)) {
1399 				end_request(CURRENT, 0);
1400 				goto repeat;
1401 			}
1402 			/*
1403 			 * setup a callback to write the track buffer
1404 			 * after a short (1 tick) delay.
1405 			 */
1406 			local_irq_save(flags);
1407 
1408 			floppy->dirty = 1;
1409 		        /* reset the timer */
1410 			mod_timer (flush_track_timer + drive, jiffies + 1);
1411 			local_irq_restore(flags);
1412 			break;
1413 		}
1414 	}
1415 	CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
1416 	CURRENT->sector += CURRENT->current_nr_sectors;
1417 
1418 	end_request(CURRENT, 1);
1419 	goto repeat;
1420 }
1421 
1422 static void do_fd_request(request_queue_t * q)
1423 {
1424 	redo_fd_request();
1425 }
1426 
1427 static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1428 {
1429 	int drive = MINOR(bdev->bd_dev) & 3;
1430 
1431 	geo->heads = unit[drive].type->heads;
1432 	geo->sectors = unit[drive].dtype->sects * unit[drive].type->sect_mult;
1433 	geo->cylinders = unit[drive].type->tracks;
1434 	return 0;
1435 }
1436 
1437 static int fd_ioctl(struct inode *inode, struct file *filp,
1438 		    unsigned int cmd, unsigned long param)
1439 {
1440 	int drive = iminor(inode) & 3;
1441 	static struct floppy_struct getprm;
1442 
1443 	switch(cmd){
1444 	case FDFMTBEG:
1445 		get_fdc(drive);
1446 		if (fd_ref[drive] > 1) {
1447 			rel_fdc();
1448 			return -EBUSY;
1449 		}
1450 		fsync_bdev(inode->i_bdev);
1451 		if (fd_motor_on(drive) == 0) {
1452 			rel_fdc();
1453 			return -ENODEV;
1454 		}
1455 		if (fd_calibrate(drive) == 0) {
1456 			rel_fdc();
1457 			return -ENXIO;
1458 		}
1459 		floppy_off(drive);
1460 		rel_fdc();
1461 		break;
1462 	case FDFMTTRK:
1463 		if (param < unit[drive].type->tracks * unit[drive].type->heads)
1464 		{
1465 			get_fdc(drive);
1466 			if (fd_seek(drive,param) != 0){
1467 				memset(unit[drive].trackbuf, FD_FILL_BYTE,
1468 				       unit[drive].dtype->sects * unit[drive].type->sect_mult * 512);
1469 				non_int_flush_track(drive);
1470 			}
1471 			floppy_off(drive);
1472 			rel_fdc();
1473 		}
1474 		else
1475 			return -EINVAL;
1476 		break;
1477 	case FDFMTEND:
1478 		floppy_off(drive);
1479 		invalidate_bdev(inode->i_bdev, 0);
1480 		break;
1481 	case FDGETPRM:
1482 		memset((void *)&getprm, 0, sizeof (getprm));
1483 		getprm.track=unit[drive].type->tracks;
1484 		getprm.head=unit[drive].type->heads;
1485 		getprm.sect=unit[drive].dtype->sects * unit[drive].type->sect_mult;
1486 		getprm.size=unit[drive].blocks;
1487 		if (copy_to_user((void *)param,
1488 				 (void *)&getprm,
1489 				 sizeof(struct floppy_struct)))
1490 			return -EFAULT;
1491 		break;
1492 	case FDSETPRM:
1493 	case FDDEFPRM:
1494 		return -EINVAL;
1495 	case FDFLUSH: /* unconditionally, even if not needed */
1496 		del_timer (flush_track_timer + drive);
1497 		non_int_flush_track(drive);
1498 		break;
1499 #ifdef RAW_IOCTL
1500 	case IOCTL_RAW_TRACK:
1501 		if (copy_to_user((void *)param, raw_buf,
1502 				 unit[drive].type->read_size))
1503 			return -EFAULT;
1504 		else
1505 			return unit[drive].type->read_size;
1506 #endif
1507 	default:
1508 		printk(KERN_DEBUG "fd_ioctl: unknown cmd %d for drive %d.",
1509 		       cmd, drive);
1510 		return -ENOSYS;
1511 	}
1512 	return 0;
1513 }
1514 
1515 static void fd_probe(int dev)
1516 {
1517 	unsigned long code;
1518 	int type;
1519 	int drive;
1520 
1521 	drive = dev & 3;
1522 	code = fd_get_drive_id(drive);
1523 
1524 	/* get drive type */
1525 	for (type = 0; type < num_dr_types; type++)
1526 		if (drive_types[type].code == code)
1527 			break;
1528 
1529 	if (type >= num_dr_types) {
1530 		printk(KERN_WARNING "fd_probe: unsupported drive type "
1531 		       "%08lx found\n", code);
1532 		unit[drive].type = &drive_types[num_dr_types-1]; /* FD_NODRIVE */
1533 		return;
1534 	}
1535 
1536 	unit[drive].type = drive_types + type;
1537 	unit[drive].track = -1;
1538 
1539 	unit[drive].disk = -1;
1540 	unit[drive].motor = 0;
1541 	unit[drive].busy = 0;
1542 	unit[drive].status = -1;
1543 }
1544 
1545 /*
1546  * floppy_open check for aliasing (/dev/fd0 can be the same as
1547  * /dev/PS0 etc), and disallows simultaneous access to the same
1548  * drive with different device numbers.
1549  */
1550 static int floppy_open(struct inode *inode, struct file *filp)
1551 {
1552 	int drive = iminor(inode) & 3;
1553 	int system =  (iminor(inode) & 4) >> 2;
1554 	int old_dev;
1555 	unsigned long flags;
1556 
1557 	old_dev = fd_device[drive];
1558 
1559 	if (fd_ref[drive] && old_dev != system)
1560 		return -EBUSY;
1561 
1562 	if (filp && filp->f_mode & 3) {
1563 		check_disk_change(inode->i_bdev);
1564 		if (filp->f_mode & 2 ) {
1565 			int wrprot;
1566 
1567 			get_fdc(drive);
1568 			fd_select (drive);
1569 			wrprot = !(ciaa.pra & DSKPROT);
1570 			fd_deselect (drive);
1571 			rel_fdc();
1572 
1573 			if (wrprot)
1574 				return -EROFS;
1575 		}
1576 	}
1577 
1578 	local_irq_save(flags);
1579 	fd_ref[drive]++;
1580 	fd_device[drive] = system;
1581 	local_irq_restore(flags);
1582 
1583 	unit[drive].dtype=&data_types[system];
1584 	unit[drive].blocks=unit[drive].type->heads*unit[drive].type->tracks*
1585 		data_types[system].sects*unit[drive].type->sect_mult;
1586 	set_capacity(unit[drive].gendisk, unit[drive].blocks);
1587 
1588 	printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
1589 	       unit[drive].type->name, data_types[system].name);
1590 
1591 	return 0;
1592 }
1593 
1594 static int floppy_release(struct inode * inode, struct file * filp)
1595 {
1596 	int drive = iminor(inode) & 3;
1597 
1598 	if (unit[drive].dirty == 1) {
1599 		del_timer (flush_track_timer + drive);
1600 		non_int_flush_track (drive);
1601 	}
1602 
1603 	if (!fd_ref[drive]--) {
1604 		printk(KERN_CRIT "floppy_release with fd_ref == 0");
1605 		fd_ref[drive] = 0;
1606 	}
1607 #ifdef MODULE
1608 /* the mod_use counter is handled this way */
1609 	floppy_off (drive | 0x40000000);
1610 #endif
1611 	return 0;
1612 }
1613 
1614 /*
1615  * floppy-change is never called from an interrupt, so we can relax a bit
1616  * here, sleep etc. Note that floppy-on tries to set current_DOR to point
1617  * to the desired drive, but it will probably not survive the sleep if
1618  * several floppies are used at the same time: thus the loop.
1619  */
1620 static int amiga_floppy_change(struct gendisk *disk)
1621 {
1622 	struct amiga_floppy_struct *p = disk->private_data;
1623 	int drive = p - unit;
1624 	int changed;
1625 	static int first_time = 1;
1626 
1627 	if (first_time)
1628 		changed = first_time--;
1629 	else {
1630 		get_fdc(drive);
1631 		fd_select (drive);
1632 		changed = !(ciaa.pra & DSKCHANGE);
1633 		fd_deselect (drive);
1634 		rel_fdc();
1635 	}
1636 
1637 	if (changed) {
1638 		fd_probe(drive);
1639 		p->track = -1;
1640 		p->dirty = 0;
1641 		writepending = 0; /* if this was true before, too bad! */
1642 		writefromint = 0;
1643 		return 1;
1644 	}
1645 	return 0;
1646 }
1647 
1648 static struct block_device_operations floppy_fops = {
1649 	.owner		= THIS_MODULE,
1650 	.open		= floppy_open,
1651 	.release	= floppy_release,
1652 	.ioctl		= fd_ioctl,
1653 	.getgeo		= fd_getgeo,
1654 	.media_changed	= amiga_floppy_change,
1655 };
1656 
1657 void __init amiga_floppy_setup (char *str, int *ints)
1658 {
1659 	printk (KERN_INFO "amiflop: Setting default df0 to %x\n", ints[1]);
1660 	fd_def_df0 = ints[1];
1661 }
1662 
1663 static int __init fd_probe_drives(void)
1664 {
1665 	int drive,drives,nomem;
1666 
1667 	printk(KERN_INFO "FD: probing units\n" KERN_INFO "found ");
1668 	drives=0;
1669 	nomem=0;
1670 	for(drive=0;drive<FD_MAX_UNITS;drive++) {
1671 		struct gendisk *disk;
1672 		fd_probe(drive);
1673 		if (unit[drive].type->code == FD_NODRIVE)
1674 			continue;
1675 		disk = alloc_disk(1);
1676 		if (!disk) {
1677 			unit[drive].type->code = FD_NODRIVE;
1678 			continue;
1679 		}
1680 		unit[drive].gendisk = disk;
1681 		drives++;
1682 		if ((unit[drive].trackbuf = kmalloc(FLOPPY_MAX_SECTORS * 512, GFP_KERNEL)) == NULL) {
1683 			printk("no mem for ");
1684 			unit[drive].type = &drive_types[num_dr_types - 1]; /* FD_NODRIVE */
1685 			drives--;
1686 			nomem = 1;
1687 		}
1688 		printk("fd%d ",drive);
1689 		disk->major = FLOPPY_MAJOR;
1690 		disk->first_minor = drive;
1691 		disk->fops = &floppy_fops;
1692 		sprintf(disk->disk_name, "fd%d", drive);
1693 		disk->private_data = &unit[drive];
1694 		disk->queue = floppy_queue;
1695 		set_capacity(disk, 880*2);
1696 		add_disk(disk);
1697 	}
1698 	if ((drives > 0) || (nomem == 0)) {
1699 		if (drives == 0)
1700 			printk("no drives");
1701 		printk("\n");
1702 		return drives;
1703 	}
1704 	printk("\n");
1705 	return -ENOMEM;
1706 }
1707 
1708 static struct kobject *floppy_find(dev_t dev, int *part, void *data)
1709 {
1710 	int drive = *part & 3;
1711 	if (unit[drive].type->code == FD_NODRIVE)
1712 		return NULL;
1713 	*part = 0;
1714 	return get_disk(unit[drive].gendisk);
1715 }
1716 
1717 int __init amiga_floppy_init(void)
1718 {
1719 	int i, ret;
1720 
1721 	if (!AMIGAHW_PRESENT(AMI_FLOPPY))
1722 		return -ENXIO;
1723 
1724 	if (register_blkdev(FLOPPY_MAJOR,"fd"))
1725 		return -EBUSY;
1726 
1727 	/*
1728 	 *  We request DSKPTR, DSKLEN and DSKDATA only, because the other
1729 	 *  floppy registers are too spreaded over the custom register space
1730 	 */
1731 	ret = -EBUSY;
1732 	if (!request_mem_region(CUSTOM_PHYSADDR+0x20, 8, "amiflop [Paula]")) {
1733 		printk("fd: cannot get floppy registers\n");
1734 		goto out_blkdev;
1735 	}
1736 
1737 	ret = -ENOMEM;
1738 	if ((raw_buf = (char *)amiga_chip_alloc (RAW_BUF_SIZE, "Floppy")) ==
1739 	    NULL) {
1740 		printk("fd: cannot get chip mem buffer\n");
1741 		goto out_memregion;
1742 	}
1743 
1744 	ret = -EBUSY;
1745 	if (request_irq(IRQ_AMIGA_DSKBLK, fd_block_done, 0, "floppy_dma", NULL)) {
1746 		printk("fd: cannot get irq for dma\n");
1747 		goto out_irq;
1748 	}
1749 
1750 	if (request_irq(IRQ_AMIGA_CIAA_TB, ms_isr, 0, "floppy_timer", NULL)) {
1751 		printk("fd: cannot get irq for timer\n");
1752 		goto out_irq2;
1753 	}
1754 
1755 	ret = -ENOMEM;
1756 	floppy_queue = blk_init_queue(do_fd_request, &amiflop_lock);
1757 	if (!floppy_queue)
1758 		goto out_queue;
1759 
1760 	ret = -ENXIO;
1761 	if (fd_probe_drives() < 1) /* No usable drives */
1762 		goto out_probe;
1763 
1764 	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
1765 				floppy_find, NULL, NULL);
1766 
1767 	/* initialize variables */
1768 	init_timer(&motor_on_timer);
1769 	motor_on_timer.expires = 0;
1770 	motor_on_timer.data = 0;
1771 	motor_on_timer.function = motor_on_callback;
1772 	for (i = 0; i < FD_MAX_UNITS; i++) {
1773 		init_timer(&motor_off_timer[i]);
1774 		motor_off_timer[i].expires = 0;
1775 		motor_off_timer[i].data = i|0x80000000;
1776 		motor_off_timer[i].function = fd_motor_off;
1777 		init_timer(&flush_track_timer[i]);
1778 		flush_track_timer[i].expires = 0;
1779 		flush_track_timer[i].data = i;
1780 		flush_track_timer[i].function = flush_track_callback;
1781 
1782 		unit[i].track = -1;
1783 	}
1784 
1785 	init_timer(&post_write_timer);
1786 	post_write_timer.expires = 0;
1787 	post_write_timer.data = 0;
1788 	post_write_timer.function = post_write;
1789 
1790 	for (i = 0; i < 128; i++)
1791 		mfmdecode[i]=255;
1792 	for (i = 0; i < 16; i++)
1793 		mfmdecode[mfmencode[i]]=i;
1794 
1795 	/* make sure that disk DMA is enabled */
1796 	custom.dmacon = DMAF_SETCLR | DMAF_DISK;
1797 
1798 	/* init ms timer */
1799 	ciaa.crb = 8; /* one-shot, stop */
1800 	return 0;
1801 
1802 out_probe:
1803 	blk_cleanup_queue(floppy_queue);
1804 out_queue:
1805 	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1806 out_irq2:
1807 	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1808 out_irq:
1809 	amiga_chip_free(raw_buf);
1810 out_memregion:
1811 	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1812 out_blkdev:
1813 	unregister_blkdev(FLOPPY_MAJOR,"fd");
1814 	return ret;
1815 }
1816 
1817 #ifdef MODULE
1818 
1819 int init_module(void)
1820 {
1821 	if (!MACH_IS_AMIGA)
1822 		return -ENXIO;
1823 	return amiga_floppy_init();
1824 }
1825 
1826 #if 0 /* not safe to unload */
1827 void cleanup_module(void)
1828 {
1829 	int i;
1830 
1831 	for( i = 0; i < FD_MAX_UNITS; i++) {
1832 		if (unit[i].type->code != FD_NODRIVE) {
1833 			del_gendisk(unit[i].gendisk);
1834 			put_disk(unit[i].gendisk);
1835 			kfree(unit[i].trackbuf);
1836 		}
1837 	}
1838 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
1839 	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1840 	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1841 	custom.dmacon = DMAF_DISK; /* disable DMA */
1842 	amiga_chip_free(raw_buf);
1843 	blk_cleanup_queue(floppy_queue);
1844 	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1845 	unregister_blkdev(FLOPPY_MAJOR, "fd");
1846 }
1847 #endif
1848 #endif
1849