xref: /openbmc/linux/drivers/block/amiflop.c (revision b6dcefde)
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 
116 /*
117  *  Macros
118  */
119 #define MOTOR_ON	(ciab.prb &= ~DSKMOTOR)
120 #define MOTOR_OFF	(ciab.prb |= DSKMOTOR)
121 #define SELECT(mask)    (ciab.prb &= ~mask)
122 #define DESELECT(mask)  (ciab.prb |= mask)
123 #define SELMASK(drive)  (1 << (3 + (drive & 3)))
124 
125 static struct fd_drive_type drive_types[] = {
126 /*  code	name	   tr he   rdsz   wrsz sm pc1 pc2 sd  st st*/
127 /*  warning: times are now in milliseconds (ms)                    */
128 { FD_DD_3,	"DD 3.5",  80, 2, 14716, 13630, 1, 80,161, 3, 18, 1},
129 { FD_HD_3,	"HD 3.5",  80, 2, 28344, 27258, 2, 80,161, 3, 18, 1},
130 { FD_DD_5,	"DD 5.25", 40, 2, 14716, 13630, 1, 40, 81, 6, 30, 2},
131 { FD_NODRIVE, "No Drive", 0, 0,     0,     0, 0,  0,  0,  0,  0, 0}
132 };
133 static int num_dr_types = ARRAY_SIZE(drive_types);
134 
135 static int amiga_read(int), dos_read(int);
136 static void amiga_write(int), dos_write(int);
137 static struct fd_data_type data_types[] = {
138 	{ "Amiga", 11 , amiga_read, amiga_write},
139 	{ "MS-Dos", 9, dos_read, dos_write}
140 };
141 
142 /* current info on each unit */
143 static struct amiga_floppy_struct unit[FD_MAX_UNITS];
144 
145 static struct timer_list flush_track_timer[FD_MAX_UNITS];
146 static struct timer_list post_write_timer;
147 static struct timer_list motor_on_timer;
148 static struct timer_list motor_off_timer[FD_MAX_UNITS];
149 static int on_attempts;
150 
151 /* Synchronization of FDC access */
152 /* request loop (trackbuffer) */
153 static volatile int fdc_busy = -1;
154 static volatile int fdc_nested;
155 static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
156 
157 static DECLARE_COMPLETION(motor_on_completion);
158 
159 static volatile int selected = -1;	/* currently selected drive */
160 
161 static int writepending;
162 static int writefromint;
163 static char *raw_buf;
164 
165 static DEFINE_SPINLOCK(amiflop_lock);
166 
167 #define RAW_BUF_SIZE 30000  /* size of raw disk data */
168 
169 /*
170  * These are global variables, as that's the easiest way to give
171  * information to interrupts. They are the data used for the current
172  * request.
173  */
174 static volatile char block_flag;
175 static DECLARE_WAIT_QUEUE_HEAD(wait_fd_block);
176 
177 /* MS-Dos MFM Coding tables (should go quick and easy) */
178 static unsigned char mfmencode[16]={
179 	0x2a, 0x29, 0x24, 0x25, 0x12, 0x11, 0x14, 0x15,
180 	0x4a, 0x49, 0x44, 0x45, 0x52, 0x51, 0x54, 0x55
181 };
182 static unsigned char mfmdecode[128];
183 
184 /* floppy internal millisecond timer stuff */
185 static DECLARE_COMPLETION(ms_wait_completion);
186 #define MS_TICKS ((amiga_eclock+50)/1000)
187 
188 /*
189  * Note that MAX_ERRORS=X doesn't imply that we retry every bad read
190  * max X times - some types of errors increase the errorcount by 2 or
191  * even 3, so we might actually retry only X/2 times before giving up.
192  */
193 #define MAX_ERRORS 12
194 
195 #define custom amiga_custom
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)
210 {
211 	complete(&ms_wait_completion);
212 	return IRQ_HANDLED;
213 }
214 
215 /* all waits are queued up
216    A more generic routine would do a schedule a la timer.device */
217 static void ms_delay(int ms)
218 {
219 	int ticks;
220 	static DEFINE_MUTEX(mutex);
221 
222 	if (ms > 0) {
223 		mutex_lock(&mutex);
224 		ticks = MS_TICKS*ms-1;
225 		ciaa.tblo=ticks%256;
226 		ciaa.tbhi=ticks/256;
227 		ciaa.crb=0x19; /*count eclock, force load, one-shoot, start */
228 		wait_for_completion(&ms_wait_completion);
229 		mutex_unlock(&mutex);
230 	}
231 }
232 
233 /* Hardware semaphore */
234 
235 /* returns true when we would get the semaphore */
236 static inline int try_fdc(int drive)
237 {
238 	drive &= 3;
239 	return ((fdc_busy < 0) || (fdc_busy == drive));
240 }
241 
242 static void get_fdc(int drive)
243 {
244 	unsigned long flags;
245 
246 	drive &= 3;
247 #ifdef DEBUG
248 	printk("get_fdc: drive %d  fdc_busy %d  fdc_nested %d\n",drive,fdc_busy,fdc_nested);
249 #endif
250 	local_irq_save(flags);
251 	wait_event(fdc_wait, try_fdc(drive));
252 	fdc_busy = drive;
253 	fdc_nested++;
254 	local_irq_restore(flags);
255 }
256 
257 static inline void rel_fdc(void)
258 {
259 #ifdef DEBUG
260 	if (fdc_nested == 0)
261 		printk("fd: unmatched rel_fdc\n");
262 	printk("rel_fdc: fdc_busy %d fdc_nested %d\n",fdc_busy,fdc_nested);
263 #endif
264 	fdc_nested--;
265 	if (fdc_nested == 0) {
266 		fdc_busy = -1;
267 		wake_up(&fdc_wait);
268 	}
269 }
270 
271 static void fd_select (int drive)
272 {
273 	unsigned char prb = ~0;
274 
275 	drive&=3;
276 #ifdef DEBUG
277 	printk("selecting %d\n",drive);
278 #endif
279 	if (drive == selected)
280 		return;
281 	get_fdc(drive);
282 	selected = drive;
283 
284 	if (unit[drive].track % 2 != 0)
285 		prb &= ~DSKSIDE;
286 	if (unit[drive].motor == 1)
287 		prb &= ~DSKMOTOR;
288 	ciab.prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
289 	ciab.prb = prb;
290 	prb &= ~SELMASK(drive);
291 	ciab.prb = prb;
292 	rel_fdc();
293 }
294 
295 static void fd_deselect (int drive)
296 {
297 	unsigned char prb;
298 	unsigned long flags;
299 
300 	drive&=3;
301 #ifdef DEBUG
302 	printk("deselecting %d\n",drive);
303 #endif
304 	if (drive != selected) {
305 		printk(KERN_WARNING "Deselecting drive %d while %d was selected!\n",drive,selected);
306 		return;
307 	}
308 
309 	get_fdc(drive);
310 	local_irq_save(flags);
311 
312 	selected = -1;
313 
314 	prb = ciab.prb;
315 	prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
316 	ciab.prb = prb;
317 
318 	local_irq_restore (flags);
319 	rel_fdc();
320 
321 }
322 
323 static void motor_on_callback(unsigned long nr)
324 {
325 	if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
326 		complete_all(&motor_on_completion);
327 	} else {
328 		motor_on_timer.expires = jiffies + HZ/10;
329 		add_timer(&motor_on_timer);
330 	}
331 }
332 
333 static int fd_motor_on(int nr)
334 {
335 	nr &= 3;
336 
337 	del_timer(motor_off_timer + nr);
338 
339 	if (!unit[nr].motor) {
340 		unit[nr].motor = 1;
341 		fd_select(nr);
342 
343 		INIT_COMPLETION(motor_on_completion);
344 		motor_on_timer.data = nr;
345 		mod_timer(&motor_on_timer, jiffies + HZ/2);
346 
347 		on_attempts = 10;
348 		wait_for_completion(&motor_on_completion);
349 		fd_deselect(nr);
350 	}
351 
352 	if (on_attempts == 0) {
353 		on_attempts = -1;
354 #if 0
355 		printk (KERN_ERR "motor_on failed, turning motor off\n");
356 		fd_motor_off (nr);
357 		return 0;
358 #else
359 		printk (KERN_WARNING "DSKRDY not set after 1.5 seconds - assuming drive is spinning notwithstanding\n");
360 #endif
361 	}
362 
363 	return 1;
364 }
365 
366 static void fd_motor_off(unsigned long drive)
367 {
368 	long calledfromint;
369 #ifdef MODULE
370 	long decusecount;
371 
372 	decusecount = drive & 0x40000000;
373 #endif
374 	calledfromint = drive & 0x80000000;
375 	drive&=3;
376 	if (calledfromint && !try_fdc(drive)) {
377 		/* We would be blocked in an interrupt, so try again later */
378 		motor_off_timer[drive].expires = jiffies + 1;
379 		add_timer(motor_off_timer + drive);
380 		return;
381 	}
382 	unit[drive].motor = 0;
383 	fd_select(drive);
384 	udelay (1);
385 	fd_deselect(drive);
386 }
387 
388 static void floppy_off (unsigned int nr)
389 {
390 	int drive;
391 
392 	drive = nr & 3;
393 	/* called this way it is always from interrupt */
394 	motor_off_timer[drive].data = nr | 0x80000000;
395 	mod_timer(motor_off_timer + drive, jiffies + 3*HZ);
396 }
397 
398 static int fd_calibrate(int drive)
399 {
400 	unsigned char prb;
401 	int n;
402 
403 	drive &= 3;
404 	get_fdc(drive);
405 	if (!fd_motor_on (drive))
406 		return 0;
407 	fd_select (drive);
408 	prb = ciab.prb;
409 	prb |= DSKSIDE;
410 	prb &= ~DSKDIREC;
411 	ciab.prb = prb;
412 	for (n = unit[drive].type->tracks/2; n != 0; --n) {
413 		if (ciaa.pra & DSKTRACK0)
414 			break;
415 		prb &= ~DSKSTEP;
416 		ciab.prb = prb;
417 		prb |= DSKSTEP;
418 		udelay (2);
419 		ciab.prb = prb;
420 		ms_delay(unit[drive].type->step_delay);
421 	}
422 	ms_delay (unit[drive].type->settle_time);
423 	prb |= DSKDIREC;
424 	n = unit[drive].type->tracks + 20;
425 	for (;;) {
426 		prb &= ~DSKSTEP;
427 		ciab.prb = prb;
428 		prb |= DSKSTEP;
429 		udelay (2);
430 		ciab.prb = prb;
431 		ms_delay(unit[drive].type->step_delay + 1);
432 		if ((ciaa.pra & DSKTRACK0) == 0)
433 			break;
434 		if (--n == 0) {
435 			printk (KERN_ERR "fd%d: calibrate failed, turning motor off\n", drive);
436 			fd_motor_off (drive);
437 			unit[drive].track = -1;
438 			rel_fdc();
439 			return 0;
440 		}
441 	}
442 	unit[drive].track = 0;
443 	ms_delay(unit[drive].type->settle_time);
444 
445 	rel_fdc();
446 	fd_deselect(drive);
447 	return 1;
448 }
449 
450 static int fd_seek(int drive, int track)
451 {
452 	unsigned char prb;
453 	int cnt;
454 
455 #ifdef DEBUG
456 	printk("seeking drive %d to track %d\n",drive,track);
457 #endif
458 	drive &= 3;
459 	get_fdc(drive);
460 	if (unit[drive].track == track) {
461 		rel_fdc();
462 		return 1;
463 	}
464 	if (!fd_motor_on(drive)) {
465 		rel_fdc();
466 		return 0;
467 	}
468 	if (unit[drive].track < 0 && !fd_calibrate(drive)) {
469 		rel_fdc();
470 		return 0;
471 	}
472 
473 	fd_select (drive);
474 	cnt = unit[drive].track/2 - track/2;
475 	prb = ciab.prb;
476 	prb |= DSKSIDE | DSKDIREC;
477 	if (track % 2 != 0)
478 		prb &= ~DSKSIDE;
479 	if (cnt < 0) {
480 		cnt = - cnt;
481 		prb &= ~DSKDIREC;
482 	}
483 	ciab.prb = prb;
484 	if (track % 2 != unit[drive].track % 2)
485 		ms_delay (unit[drive].type->side_time);
486 	unit[drive].track = track;
487 	if (cnt == 0) {
488 		rel_fdc();
489 		fd_deselect(drive);
490 		return 1;
491 	}
492 	do {
493 		prb &= ~DSKSTEP;
494 		ciab.prb = prb;
495 		prb |= DSKSTEP;
496 		udelay (1);
497 		ciab.prb = prb;
498 		ms_delay (unit[drive].type->step_delay);
499 	} while (--cnt != 0);
500 	ms_delay (unit[drive].type->settle_time);
501 
502 	rel_fdc();
503 	fd_deselect(drive);
504 	return 1;
505 }
506 
507 static unsigned long fd_get_drive_id(int drive)
508 {
509 	int i;
510 	ulong id = 0;
511 
512   	drive&=3;
513   	get_fdc(drive);
514 	/* set up for ID */
515 	MOTOR_ON;
516 	udelay(2);
517 	SELECT(SELMASK(drive));
518 	udelay(2);
519 	DESELECT(SELMASK(drive));
520 	udelay(2);
521 	MOTOR_OFF;
522 	udelay(2);
523 	SELECT(SELMASK(drive));
524 	udelay(2);
525 	DESELECT(SELMASK(drive));
526 	udelay(2);
527 
528 	/* loop and read disk ID */
529 	for (i=0; i<32; i++) {
530 		SELECT(SELMASK(drive));
531 		udelay(2);
532 
533 		/* read and store value of DSKRDY */
534 		id <<= 1;
535 		id |= (ciaa.pra & DSKRDY) ? 0 : 1;	/* cia regs are low-active! */
536 
537 		DESELECT(SELMASK(drive));
538 	}
539 
540 	rel_fdc();
541 
542         /*
543          * RB: At least A500/A2000's df0: don't identify themselves.
544          * As every (real) Amiga has at least a 3.5" DD drive as df0:
545          * we default to that if df0: doesn't identify as a certain
546          * type.
547          */
548         if(drive == 0 && id == FD_NODRIVE)
549 	{
550                 id = fd_def_df0;
551                 printk(KERN_NOTICE "fd: drive 0 didn't identify, setting default %08lx\n", (ulong)fd_def_df0);
552 	}
553 	/* return the ID value */
554 	return (id);
555 }
556 
557 static irqreturn_t fd_block_done(int irq, void *dummy)
558 {
559 	if (block_flag)
560 		custom.dsklen = 0x4000;
561 
562 	if (block_flag == 2) { /* writing */
563 		writepending = 2;
564 		post_write_timer.expires = jiffies + 1; /* at least 2 ms */
565 		post_write_timer.data = selected;
566 		add_timer(&post_write_timer);
567 	}
568 	else {                /* reading */
569 		block_flag = 0;
570 		wake_up (&wait_fd_block);
571 	}
572 	return IRQ_HANDLED;
573 }
574 
575 static void raw_read(int drive)
576 {
577 	drive&=3;
578 	get_fdc(drive);
579 	wait_event(wait_fd_block, !block_flag);
580 	fd_select(drive);
581 	/* setup adkcon bits correctly */
582 	custom.adkcon = ADK_MSBSYNC;
583 	custom.adkcon = ADK_SETCLR|ADK_WORDSYNC|ADK_FAST;
584 
585 	custom.dsksync = MFM_SYNC;
586 
587 	custom.dsklen = 0;
588 	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
589 	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
590 	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
591 
592 	block_flag = 1;
593 
594 	wait_event(wait_fd_block, !block_flag);
595 
596 	custom.dsklen = 0;
597 	fd_deselect(drive);
598 	rel_fdc();
599 }
600 
601 static int raw_write(int drive)
602 {
603 	ushort adk;
604 
605 	drive&=3;
606 	get_fdc(drive); /* corresponds to rel_fdc() in post_write() */
607 	if ((ciaa.pra & DSKPROT) == 0) {
608 		rel_fdc();
609 		return 0;
610 	}
611 	wait_event(wait_fd_block, !block_flag);
612 	fd_select(drive);
613 	/* clear adkcon bits */
614 	custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
615 	/* set appropriate adkcon bits */
616 	adk = ADK_SETCLR|ADK_FAST;
617 	if ((ulong)unit[drive].track >= unit[drive].type->precomp2)
618 		adk |= ADK_PRECOMP1;
619 	else if ((ulong)unit[drive].track >= unit[drive].type->precomp1)
620 		adk |= ADK_PRECOMP0;
621 	custom.adkcon = adk;
622 
623 	custom.dsklen = DSKLEN_WRITE;
624 	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
625 	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
626 	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
627 
628 	block_flag = 2;
629 	return 1;
630 }
631 
632 /*
633  * to be called at least 2ms after the write has finished but before any
634  * other access to the hardware.
635  */
636 static void post_write (unsigned long drive)
637 {
638 #ifdef DEBUG
639 	printk("post_write for drive %ld\n",drive);
640 #endif
641 	drive &= 3;
642 	custom.dsklen = 0;
643 	block_flag = 0;
644 	writepending = 0;
645 	writefromint = 0;
646 	unit[drive].dirty = 0;
647 	wake_up(&wait_fd_block);
648 	fd_deselect(drive);
649 	rel_fdc(); /* corresponds to get_fdc() in raw_write */
650 }
651 
652 
653 /*
654  * The following functions are to convert the block contents into raw data
655  * written to disk and vice versa.
656  * (Add other formats here ;-))
657  */
658 
659 static unsigned long scan_sync(unsigned long raw, unsigned long end)
660 {
661 	ushort *ptr = (ushort *)raw, *endp = (ushort *)end;
662 
663 	while (ptr < endp && *ptr++ != 0x4489)
664 		;
665 	if (ptr < endp) {
666 		while (*ptr == 0x4489 && ptr < endp)
667 			ptr++;
668 		return (ulong)ptr;
669 	}
670 	return 0;
671 }
672 
673 static inline unsigned long checksum(unsigned long *addr, int len)
674 {
675 	unsigned long csum = 0;
676 
677 	len /= sizeof(*addr);
678 	while (len-- > 0)
679 		csum ^= *addr++;
680 	csum = ((csum>>1) & 0x55555555)  ^  (csum & 0x55555555);
681 
682 	return csum;
683 }
684 
685 static unsigned long decode (unsigned long *data, unsigned long *raw,
686 			     int len)
687 {
688 	ulong *odd, *even;
689 
690 	/* convert length from bytes to longwords */
691 	len >>= 2;
692 	odd = raw;
693 	even = odd + len;
694 
695 	/* prepare return pointer */
696 	raw += len * 2;
697 
698 	do {
699 		*data++ = ((*odd++ & 0x55555555) << 1) | (*even++ & 0x55555555);
700 	} while (--len != 0);
701 
702 	return (ulong)raw;
703 }
704 
705 struct header {
706 	unsigned char magic;
707 	unsigned char track;
708 	unsigned char sect;
709 	unsigned char ord;
710 	unsigned char labels[16];
711 	unsigned long hdrchk;
712 	unsigned long datachk;
713 };
714 
715 static int amiga_read(int drive)
716 {
717 	unsigned long raw;
718 	unsigned long end;
719 	int scnt;
720 	unsigned long csum;
721 	struct header hdr;
722 
723 	drive&=3;
724 	raw = (long) raw_buf;
725 	end = raw + unit[drive].type->read_size;
726 
727 	for (scnt = 0;scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
728 		if (!(raw = scan_sync(raw, end))) {
729 			printk (KERN_INFO "can't find sync for sector %d\n", scnt);
730 			return MFM_NOSYNC;
731 		}
732 
733 		raw = decode ((ulong *)&hdr.magic, (ulong *)raw, 4);
734 		raw = decode ((ulong *)&hdr.labels, (ulong *)raw, 16);
735 		raw = decode ((ulong *)&hdr.hdrchk, (ulong *)raw, 4);
736 		raw = decode ((ulong *)&hdr.datachk, (ulong *)raw, 4);
737 		csum = checksum((ulong *)&hdr,
738 				(char *)&hdr.hdrchk-(char *)&hdr);
739 
740 #ifdef DEBUG
741 		printk ("(%x,%d,%d,%d) (%lx,%lx,%lx,%lx) %lx %lx\n",
742 			hdr.magic, hdr.track, hdr.sect, hdr.ord,
743 			*(ulong *)&hdr.labels[0], *(ulong *)&hdr.labels[4],
744 			*(ulong *)&hdr.labels[8], *(ulong *)&hdr.labels[12],
745 			hdr.hdrchk, hdr.datachk);
746 #endif
747 
748 		if (hdr.hdrchk != csum) {
749 			printk(KERN_INFO "MFM_HEADER: %08lx,%08lx\n", hdr.hdrchk, csum);
750 			return MFM_HEADER;
751 		}
752 
753 		/* verify track */
754 		if (hdr.track != unit[drive].track) {
755 			printk(KERN_INFO "MFM_TRACK: %d, %d\n", hdr.track, unit[drive].track);
756 			return MFM_TRACK;
757 		}
758 
759 		raw = decode ((ulong *)(unit[drive].trackbuf + hdr.sect*512),
760 			      (ulong *)raw, 512);
761 		csum = checksum((ulong *)(unit[drive].trackbuf + hdr.sect*512), 512);
762 
763 		if (hdr.datachk != csum) {
764 			printk(KERN_INFO "MFM_DATA: (%x:%d:%d:%d) sc=%d %lx, %lx\n",
765 			       hdr.magic, hdr.track, hdr.sect, hdr.ord, scnt,
766 			       hdr.datachk, csum);
767 			printk (KERN_INFO "data=(%lx,%lx,%lx,%lx)\n",
768 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[0],
769 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[1],
770 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[2],
771 				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[3]);
772 			return MFM_DATA;
773 		}
774 	}
775 
776 	return 0;
777 }
778 
779 static void encode(unsigned long data, unsigned long *dest)
780 {
781 	unsigned long data2;
782 
783 	data &= 0x55555555;
784 	data2 = data ^ 0x55555555;
785 	data |= ((data2 >> 1) | 0x80000000) & (data2 << 1);
786 
787 	if (*(dest - 1) & 0x00000001)
788 		data &= 0x7FFFFFFF;
789 
790 	*dest = data;
791 }
792 
793 static void encode_block(unsigned long *dest, unsigned long *src, int len)
794 {
795 	int cnt, to_cnt = 0;
796 	unsigned long data;
797 
798 	/* odd bits */
799 	for (cnt = 0; cnt < len / 4; cnt++) {
800 		data = src[cnt] >> 1;
801 		encode(data, dest + to_cnt++);
802 	}
803 
804 	/* even bits */
805 	for (cnt = 0; cnt < len / 4; cnt++) {
806 		data = src[cnt];
807 		encode(data, dest + to_cnt++);
808 	}
809 }
810 
811 static unsigned long *putsec(int disk, unsigned long *raw, int cnt)
812 {
813 	struct header hdr;
814 	int i;
815 
816 	disk&=3;
817 	*raw = (raw[-1]&1) ? 0x2AAAAAAA : 0xAAAAAAAA;
818 	raw++;
819 	*raw++ = 0x44894489;
820 
821 	hdr.magic = 0xFF;
822 	hdr.track = unit[disk].track;
823 	hdr.sect = cnt;
824 	hdr.ord = unit[disk].dtype->sects * unit[disk].type->sect_mult - cnt;
825 	for (i = 0; i < 16; i++)
826 		hdr.labels[i] = 0;
827 	hdr.hdrchk = checksum((ulong *)&hdr,
828 			      (char *)&hdr.hdrchk-(char *)&hdr);
829 	hdr.datachk = checksum((ulong *)(unit[disk].trackbuf+cnt*512), 512);
830 
831 	encode_block(raw, (ulong *)&hdr.magic, 4);
832 	raw += 2;
833 	encode_block(raw, (ulong *)&hdr.labels, 16);
834 	raw += 8;
835 	encode_block(raw, (ulong *)&hdr.hdrchk, 4);
836 	raw += 2;
837 	encode_block(raw, (ulong *)&hdr.datachk, 4);
838 	raw += 2;
839 	encode_block(raw, (ulong *)(unit[disk].trackbuf+cnt*512), 512);
840 	raw += 256;
841 
842 	return raw;
843 }
844 
845 static void amiga_write(int disk)
846 {
847 	unsigned int cnt;
848 	unsigned long *ptr = (unsigned long *)raw_buf;
849 
850 	disk&=3;
851 	/* gap space */
852 	for (cnt = 0; cnt < 415 * unit[disk].type->sect_mult; cnt++)
853 		*ptr++ = 0xaaaaaaaa;
854 
855 	/* sectors */
856 	for (cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
857 		ptr = putsec (disk, ptr, cnt);
858 	*(ushort *)ptr = (ptr[-1]&1) ? 0x2AA8 : 0xAAA8;
859 }
860 
861 
862 struct dos_header {
863 	unsigned char track,   /* 0-80 */
864 		side,    /* 0-1 */
865 		sec,     /* 0-...*/
866 		len_desc;/* 2 */
867 	unsigned short crc;     /* on 68000 we got an alignment problem,
868 				   but this compiler solves it  by adding silently
869 				   adding a pad byte so data won't fit
870 				   and this took about 3h to discover.... */
871 	unsigned char gap1[22];     /* for longword-alignedness (0x4e) */
872 };
873 
874 /* crc routines are borrowed from the messydos-handler  */
875 
876 /* excerpt from the messydos-device
877 ; The CRC is computed not only over the actual data, but including
878 ; the SYNC mark (3 * $a1) and the 'ID/DATA - Address Mark' ($fe/$fb).
879 ; As we don't read or encode these fields into our buffers, we have to
880 ; preload the registers containing the CRC with the values they would have
881 ; after stepping over these fields.
882 ;
883 ; How CRCs "really" work:
884 ;
885 ; First, you should regard a bitstring as a series of coefficients of
886 ; polynomials. We calculate with these polynomials in modulo-2
887 ; arithmetic, in which both add and subtract are done the same as
888 ; exclusive-or. Now, we modify our data (a very long polynomial) in
889 ; such a way that it becomes divisible by the CCITT-standard 16-bit
890 ;		 16   12   5
891 ; polynomial:	x  + x	+ x + 1, represented by $11021. The easiest
892 ; way to do this would be to multiply (using proper arithmetic) our
893 ; datablock with $11021. So we have:
894 ;   data * $11021		 =
895 ;   data * ($10000 + $1021)      =
896 ;   data * $10000 + data * $1021
897 ; The left part of this is simple: Just add two 0 bytes. But then
898 ; the right part (data $1021) remains difficult and even could have
899 ; a carry into the left part. The solution is to use a modified
900 ; multiplication, which has a result that is not correct, but with
901 ; a difference of any multiple of $11021. We then only need to keep
902 ; the 16 least significant bits of the result.
903 ;
904 ; The following algorithm does this for us:
905 ;
906 ;   unsigned char *data, c, crclo, crchi;
907 ;   while (not done) {
908 ;	c = *data++ + crchi;
909 ;	crchi = (@ c) >> 8 + crclo;
910 ;	crclo = @ c;
911 ;   }
912 ;
913 ; Remember, + is done with EOR, the @ operator is in two tables (high
914 ; and low byte separately), which is calculated as
915 ;
916 ;      $1021 * (c & $F0)
917 ;  xor $1021 * (c & $0F)
918 ;  xor $1021 * (c >> 4)         (* is regular multiplication)
919 ;
920 ;
921 ; Anyway, the end result is the same as the remainder of the division of
922 ; the data by $11021. I am afraid I need to study theory a bit more...
923 
924 
925 my only works was to code this from manx to C....
926 
927 */
928 
929 static ushort dos_crc(void * data_a3, int data_d0, int data_d1, int data_d3)
930 {
931 	static unsigned char CRCTable1[] = {
932 		0x00,0x10,0x20,0x30,0x40,0x50,0x60,0x70,0x81,0x91,0xa1,0xb1,0xc1,0xd1,0xe1,0xf1,
933 		0x12,0x02,0x32,0x22,0x52,0x42,0x72,0x62,0x93,0x83,0xb3,0xa3,0xd3,0xc3,0xf3,0xe3,
934 		0x24,0x34,0x04,0x14,0x64,0x74,0x44,0x54,0xa5,0xb5,0x85,0x95,0xe5,0xf5,0xc5,0xd5,
935 		0x36,0x26,0x16,0x06,0x76,0x66,0x56,0x46,0xb7,0xa7,0x97,0x87,0xf7,0xe7,0xd7,0xc7,
936 		0x48,0x58,0x68,0x78,0x08,0x18,0x28,0x38,0xc9,0xd9,0xe9,0xf9,0x89,0x99,0xa9,0xb9,
937 		0x5a,0x4a,0x7a,0x6a,0x1a,0x0a,0x3a,0x2a,0xdb,0xcb,0xfb,0xeb,0x9b,0x8b,0xbb,0xab,
938 		0x6c,0x7c,0x4c,0x5c,0x2c,0x3c,0x0c,0x1c,0xed,0xfd,0xcd,0xdd,0xad,0xbd,0x8d,0x9d,
939 		0x7e,0x6e,0x5e,0x4e,0x3e,0x2e,0x1e,0x0e,0xff,0xef,0xdf,0xcf,0xbf,0xaf,0x9f,0x8f,
940 		0x91,0x81,0xb1,0xa1,0xd1,0xc1,0xf1,0xe1,0x10,0x00,0x30,0x20,0x50,0x40,0x70,0x60,
941 		0x83,0x93,0xa3,0xb3,0xc3,0xd3,0xe3,0xf3,0x02,0x12,0x22,0x32,0x42,0x52,0x62,0x72,
942 		0xb5,0xa5,0x95,0x85,0xf5,0xe5,0xd5,0xc5,0x34,0x24,0x14,0x04,0x74,0x64,0x54,0x44,
943 		0xa7,0xb7,0x87,0x97,0xe7,0xf7,0xc7,0xd7,0x26,0x36,0x06,0x16,0x66,0x76,0x46,0x56,
944 		0xd9,0xc9,0xf9,0xe9,0x99,0x89,0xb9,0xa9,0x58,0x48,0x78,0x68,0x18,0x08,0x38,0x28,
945 		0xcb,0xdb,0xeb,0xfb,0x8b,0x9b,0xab,0xbb,0x4a,0x5a,0x6a,0x7a,0x0a,0x1a,0x2a,0x3a,
946 		0xfd,0xed,0xdd,0xcd,0xbd,0xad,0x9d,0x8d,0x7c,0x6c,0x5c,0x4c,0x3c,0x2c,0x1c,0x0c,
947 		0xef,0xff,0xcf,0xdf,0xaf,0xbf,0x8f,0x9f,0x6e,0x7e,0x4e,0x5e,0x2e,0x3e,0x0e,0x1e
948 	};
949 
950 	static unsigned char CRCTable2[] = {
951 		0x00,0x21,0x42,0x63,0x84,0xa5,0xc6,0xe7,0x08,0x29,0x4a,0x6b,0x8c,0xad,0xce,0xef,
952 		0x31,0x10,0x73,0x52,0xb5,0x94,0xf7,0xd6,0x39,0x18,0x7b,0x5a,0xbd,0x9c,0xff,0xde,
953 		0x62,0x43,0x20,0x01,0xe6,0xc7,0xa4,0x85,0x6a,0x4b,0x28,0x09,0xee,0xcf,0xac,0x8d,
954 		0x53,0x72,0x11,0x30,0xd7,0xf6,0x95,0xb4,0x5b,0x7a,0x19,0x38,0xdf,0xfe,0x9d,0xbc,
955 		0xc4,0xe5,0x86,0xa7,0x40,0x61,0x02,0x23,0xcc,0xed,0x8e,0xaf,0x48,0x69,0x0a,0x2b,
956 		0xf5,0xd4,0xb7,0x96,0x71,0x50,0x33,0x12,0xfd,0xdc,0xbf,0x9e,0x79,0x58,0x3b,0x1a,
957 		0xa6,0x87,0xe4,0xc5,0x22,0x03,0x60,0x41,0xae,0x8f,0xec,0xcd,0x2a,0x0b,0x68,0x49,
958 		0x97,0xb6,0xd5,0xf4,0x13,0x32,0x51,0x70,0x9f,0xbe,0xdd,0xfc,0x1b,0x3a,0x59,0x78,
959 		0x88,0xa9,0xca,0xeb,0x0c,0x2d,0x4e,0x6f,0x80,0xa1,0xc2,0xe3,0x04,0x25,0x46,0x67,
960 		0xb9,0x98,0xfb,0xda,0x3d,0x1c,0x7f,0x5e,0xb1,0x90,0xf3,0xd2,0x35,0x14,0x77,0x56,
961 		0xea,0xcb,0xa8,0x89,0x6e,0x4f,0x2c,0x0d,0xe2,0xc3,0xa0,0x81,0x66,0x47,0x24,0x05,
962 		0xdb,0xfa,0x99,0xb8,0x5f,0x7e,0x1d,0x3c,0xd3,0xf2,0x91,0xb0,0x57,0x76,0x15,0x34,
963 		0x4c,0x6d,0x0e,0x2f,0xc8,0xe9,0x8a,0xab,0x44,0x65,0x06,0x27,0xc0,0xe1,0x82,0xa3,
964 		0x7d,0x5c,0x3f,0x1e,0xf9,0xd8,0xbb,0x9a,0x75,0x54,0x37,0x16,0xf1,0xd0,0xb3,0x92,
965 		0x2e,0x0f,0x6c,0x4d,0xaa,0x8b,0xe8,0xc9,0x26,0x07,0x64,0x45,0xa2,0x83,0xe0,0xc1,
966 		0x1f,0x3e,0x5d,0x7c,0x9b,0xba,0xd9,0xf8,0x17,0x36,0x55,0x74,0x93,0xb2,0xd1,0xf0
967 	};
968 
969 /* look at the asm-code - what looks in C a bit strange is almost as good as handmade */
970 	register int i;
971 	register unsigned char *CRCT1, *CRCT2, *data, c, crch, crcl;
972 
973 	CRCT1=CRCTable1;
974 	CRCT2=CRCTable2;
975 	data=data_a3;
976 	crcl=data_d1;
977 	crch=data_d0;
978 	for (i=data_d3; i>=0; i--) {
979 		c = (*data++) ^ crch;
980 		crch = CRCT1[c] ^ crcl;
981 		crcl = CRCT2[c];
982 	}
983 	return (crch<<8)|crcl;
984 }
985 
986 static inline ushort dos_hdr_crc (struct dos_header *hdr)
987 {
988 	return dos_crc(&(hdr->track), 0xb2, 0x30, 3); /* precomputed magic */
989 }
990 
991 static inline ushort dos_data_crc(unsigned char *data)
992 {
993 	return dos_crc(data, 0xe2, 0x95 ,511); /* precomputed magic */
994 }
995 
996 static inline unsigned char dos_decode_byte(ushort word)
997 {
998 	register ushort w2;
999 	register unsigned char byte;
1000 	register unsigned char *dec = mfmdecode;
1001 
1002 	w2=word;
1003 	w2>>=8;
1004 	w2&=127;
1005 	byte = dec[w2];
1006 	byte <<= 4;
1007 	w2 = word & 127;
1008 	byte |= dec[w2];
1009 	return byte;
1010 }
1011 
1012 static unsigned long dos_decode(unsigned char *data, unsigned short *raw, int len)
1013 {
1014 	int i;
1015 
1016 	for (i = 0; i < len; i++)
1017 		*data++=dos_decode_byte(*raw++);
1018 	return ((ulong)raw);
1019 }
1020 
1021 #ifdef DEBUG
1022 static void dbg(unsigned long ptr)
1023 {
1024 	printk("raw data @%08lx: %08lx, %08lx ,%08lx, %08lx\n", ptr,
1025 	       ((ulong *)ptr)[0], ((ulong *)ptr)[1],
1026 	       ((ulong *)ptr)[2], ((ulong *)ptr)[3]);
1027 }
1028 #endif
1029 
1030 static int dos_read(int drive)
1031 {
1032 	unsigned long end;
1033 	unsigned long raw;
1034 	int scnt;
1035 	unsigned short crc,data_crc[2];
1036 	struct dos_header hdr;
1037 
1038 	drive&=3;
1039 	raw = (long) raw_buf;
1040 	end = raw + unit[drive].type->read_size;
1041 
1042 	for (scnt=0; scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
1043 		do { /* search for the right sync of each sec-hdr */
1044 			if (!(raw = scan_sync (raw, end))) {
1045 				printk(KERN_INFO "dos_read: no hdr sync on "
1046 				       "track %d, unit %d for sector %d\n",
1047 				       unit[drive].track,drive,scnt);
1048 				return MFM_NOSYNC;
1049 			}
1050 #ifdef DEBUG
1051 			dbg(raw);
1052 #endif
1053 		} while (*((ushort *)raw)!=0x5554); /* loop usually only once done */
1054 		raw+=2; /* skip over headermark */
1055 		raw = dos_decode((unsigned char *)&hdr,(ushort *) raw,8);
1056 		crc = dos_hdr_crc(&hdr);
1057 
1058 #ifdef DEBUG
1059 		printk("(%3d,%d,%2d,%d) %x\n", hdr.track, hdr.side,
1060 		       hdr.sec, hdr.len_desc, hdr.crc);
1061 #endif
1062 
1063 		if (crc != hdr.crc) {
1064 			printk(KERN_INFO "dos_read: MFM_HEADER %04x,%04x\n",
1065 			       hdr.crc, crc);
1066 			return MFM_HEADER;
1067 		}
1068 		if (hdr.track != unit[drive].track/unit[drive].type->heads) {
1069 			printk(KERN_INFO "dos_read: MFM_TRACK %d, %d\n",
1070 			       hdr.track,
1071 			       unit[drive].track/unit[drive].type->heads);
1072 			return MFM_TRACK;
1073 		}
1074 
1075 		if (hdr.side != unit[drive].track%unit[drive].type->heads) {
1076 			printk(KERN_INFO "dos_read: MFM_SIDE %d, %d\n",
1077 			       hdr.side,
1078 			       unit[drive].track%unit[drive].type->heads);
1079 			return MFM_TRACK;
1080 		}
1081 
1082 		if (hdr.len_desc != 2) {
1083 			printk(KERN_INFO "dos_read: unknown sector len "
1084 			       "descriptor %d\n", hdr.len_desc);
1085 			return MFM_DATA;
1086 		}
1087 #ifdef DEBUG
1088 		printk("hdr accepted\n");
1089 #endif
1090 		if (!(raw = scan_sync (raw, end))) {
1091 			printk(KERN_INFO "dos_read: no data sync on track "
1092 			       "%d, unit %d for sector%d, disk sector %d\n",
1093 			       unit[drive].track, drive, scnt, hdr.sec);
1094 			return MFM_NOSYNC;
1095 		}
1096 #ifdef DEBUG
1097 		dbg(raw);
1098 #endif
1099 
1100 		if (*((ushort *)raw)!=0x5545) {
1101 			printk(KERN_INFO "dos_read: no data mark after "
1102 			       "sync (%d,%d,%d,%d) sc=%d\n",
1103 			       hdr.track,hdr.side,hdr.sec,hdr.len_desc,scnt);
1104 			return MFM_NOSYNC;
1105 		}
1106 
1107 		raw+=2;  /* skip data mark (included in checksum) */
1108 		raw = dos_decode((unsigned char *)(unit[drive].trackbuf + (hdr.sec - 1) * 512), (ushort *) raw, 512);
1109 		raw = dos_decode((unsigned char  *)data_crc,(ushort *) raw,4);
1110 		crc = dos_data_crc(unit[drive].trackbuf + (hdr.sec - 1) * 512);
1111 
1112 		if (crc != data_crc[0]) {
1113 			printk(KERN_INFO "dos_read: MFM_DATA (%d,%d,%d,%d) "
1114 			       "sc=%d, %x %x\n", hdr.track, hdr.side,
1115 			       hdr.sec, hdr.len_desc, scnt,data_crc[0], crc);
1116 			printk(KERN_INFO "data=(%lx,%lx,%lx,%lx,...)\n",
1117 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[0],
1118 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[1],
1119 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[2],
1120 			       ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[3]);
1121 			return MFM_DATA;
1122 		}
1123 	}
1124 	return 0;
1125 }
1126 
1127 static inline ushort dos_encode_byte(unsigned char byte)
1128 {
1129 	register unsigned char *enc, b2, b1;
1130 	register ushort word;
1131 
1132 	enc=mfmencode;
1133 	b1=byte;
1134 	b2=b1>>4;
1135 	b1&=15;
1136 	word=enc[b2] <<8 | enc [b1];
1137 	return (word|((word&(256|64)) ? 0: 128));
1138 }
1139 
1140 static void dos_encode_block(ushort *dest, unsigned char *src, int len)
1141 {
1142 	int i;
1143 
1144 	for (i = 0; i < len; i++) {
1145 		*dest=dos_encode_byte(*src++);
1146 		*dest|=((dest[-1]&1)||(*dest&0x4000))? 0: 0x8000;
1147 		dest++;
1148 	}
1149 }
1150 
1151 static unsigned long *ms_putsec(int drive, unsigned long *raw, int cnt)
1152 {
1153 	static struct dos_header hdr={0,0,0,2,0,
1154 	  {78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78}};
1155 	int i;
1156 	static ushort crc[2]={0,0x4e4e};
1157 
1158 	drive&=3;
1159 /* id gap 1 */
1160 /* the MFM word before is always 9254 */
1161 	for(i=0;i<6;i++)
1162 		*raw++=0xaaaaaaaa;
1163 /* 3 sync + 1 headermark */
1164 	*raw++=0x44894489;
1165 	*raw++=0x44895554;
1166 
1167 /* fill in the variable parts of the header */
1168 	hdr.track=unit[drive].track/unit[drive].type->heads;
1169 	hdr.side=unit[drive].track%unit[drive].type->heads;
1170 	hdr.sec=cnt+1;
1171 	hdr.crc=dos_hdr_crc(&hdr);
1172 
1173 /* header (without "magic") and id gap 2*/
1174 	dos_encode_block((ushort *)raw,(unsigned char *) &hdr.track,28);
1175 	raw+=14;
1176 
1177 /*id gap 3 */
1178 	for(i=0;i<6;i++)
1179 		*raw++=0xaaaaaaaa;
1180 
1181 /* 3 syncs and 1 datamark */
1182 	*raw++=0x44894489;
1183 	*raw++=0x44895545;
1184 
1185 /* data */
1186 	dos_encode_block((ushort *)raw,
1187 			 (unsigned char *)unit[drive].trackbuf+cnt*512,512);
1188 	raw+=256;
1189 
1190 /*data crc + jd's special gap (long words :-/) */
1191 	crc[0]=dos_data_crc(unit[drive].trackbuf+cnt*512);
1192 	dos_encode_block((ushort *) raw,(unsigned char *)crc,4);
1193 	raw+=2;
1194 
1195 /* data gap */
1196 	for(i=0;i<38;i++)
1197 		*raw++=0x92549254;
1198 
1199 	return raw; /* wrote 652 MFM words */
1200 }
1201 
1202 static void dos_write(int disk)
1203 {
1204 	int cnt;
1205 	unsigned long raw = (unsigned long) raw_buf;
1206 	unsigned long *ptr=(unsigned long *)raw;
1207 
1208 	disk&=3;
1209 /* really gap4 + indexgap , but we write it first and round it up */
1210 	for (cnt=0;cnt<425;cnt++)
1211 		*ptr++=0x92549254;
1212 
1213 /* the following is just guessed */
1214 	if (unit[disk].type->sect_mult==2)  /* check for HD-Disks */
1215 		for(cnt=0;cnt<473;cnt++)
1216 			*ptr++=0x92549254;
1217 
1218 /* now the index marks...*/
1219 	for (cnt=0;cnt<20;cnt++)
1220 		*ptr++=0x92549254;
1221 	for (cnt=0;cnt<6;cnt++)
1222 		*ptr++=0xaaaaaaaa;
1223 	*ptr++=0x52245224;
1224 	*ptr++=0x52245552;
1225 	for (cnt=0;cnt<20;cnt++)
1226 		*ptr++=0x92549254;
1227 
1228 /* sectors */
1229 	for(cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
1230 		ptr=ms_putsec(disk,ptr,cnt);
1231 
1232 	*(ushort *)ptr = 0xaaa8; /* MFM word before is always 0x9254 */
1233 }
1234 
1235 /*
1236  * Here comes the high level stuff (i.e. the filesystem interface)
1237  * and helper functions.
1238  * Normally this should be the only part that has to be adapted to
1239  * different kernel versions.
1240  */
1241 
1242 /* FIXME: this assumes the drive is still spinning -
1243  * which is only true if we complete writing a track within three seconds
1244  */
1245 static void flush_track_callback(unsigned long nr)
1246 {
1247 	nr&=3;
1248 	writefromint = 1;
1249 	if (!try_fdc(nr)) {
1250 		/* we might block in an interrupt, so try again later */
1251 		flush_track_timer[nr].expires = jiffies + 1;
1252 		add_timer(flush_track_timer + nr);
1253 		return;
1254 	}
1255 	get_fdc(nr);
1256 	(*unit[nr].dtype->write_fkt)(nr);
1257 	if (!raw_write(nr)) {
1258 		printk (KERN_NOTICE "floppy disk write protected\n");
1259 		writefromint = 0;
1260 		writepending = 0;
1261 	}
1262 	rel_fdc();
1263 }
1264 
1265 static int non_int_flush_track (unsigned long nr)
1266 {
1267 	unsigned long flags;
1268 
1269 	nr&=3;
1270 	writefromint = 0;
1271 	del_timer(&post_write_timer);
1272 	get_fdc(nr);
1273 	if (!fd_motor_on(nr)) {
1274 		writepending = 0;
1275 		rel_fdc();
1276 		return 0;
1277 	}
1278 	local_irq_save(flags);
1279 	if (writepending != 2) {
1280 		local_irq_restore(flags);
1281 		(*unit[nr].dtype->write_fkt)(nr);
1282 		if (!raw_write(nr)) {
1283 			printk (KERN_NOTICE "floppy disk write protected "
1284 				"in write!\n");
1285 			writepending = 0;
1286 			return 0;
1287 		}
1288 		wait_event(wait_fd_block, block_flag != 2);
1289 	}
1290 	else {
1291 		local_irq_restore(flags);
1292 		ms_delay(2); /* 2 ms post_write delay */
1293 		post_write(nr);
1294 	}
1295 	rel_fdc();
1296 	return 1;
1297 }
1298 
1299 static int get_track(int drive, int track)
1300 {
1301 	int error, errcnt;
1302 
1303 	drive&=3;
1304 	if (unit[drive].track == track)
1305 		return 0;
1306 	get_fdc(drive);
1307 	if (!fd_motor_on(drive)) {
1308 		rel_fdc();
1309 		return -1;
1310 	}
1311 
1312 	if (unit[drive].dirty == 1) {
1313 		del_timer (flush_track_timer + drive);
1314 		non_int_flush_track (drive);
1315 	}
1316 	errcnt = 0;
1317 	while (errcnt < MAX_ERRORS) {
1318 		if (!fd_seek(drive, track))
1319 			return -1;
1320 		raw_read(drive);
1321 		error = (*unit[drive].dtype->read_fkt)(drive);
1322 		if (error == 0) {
1323 			rel_fdc();
1324 			return 0;
1325 		}
1326 		/* Read Error Handling: recalibrate and try again */
1327 		unit[drive].track = -1;
1328 		errcnt++;
1329 	}
1330 	rel_fdc();
1331 	return -1;
1332 }
1333 
1334 static void redo_fd_request(void)
1335 {
1336 	struct request *rq;
1337 	unsigned int cnt, block, track, sector;
1338 	int drive;
1339 	struct amiga_floppy_struct *floppy;
1340 	char *data;
1341 	unsigned long flags;
1342 	int err;
1343 
1344 next_req:
1345 	rq = blk_fetch_request(floppy_queue);
1346 	if (!rq) {
1347 		/* Nothing left to do */
1348 		return;
1349 	}
1350 
1351 	floppy = rq->rq_disk->private_data;
1352 	drive = floppy - unit;
1353 
1354 next_segment:
1355 	/* Here someone could investigate to be more efficient */
1356 	for (cnt = 0, err = 0; cnt < blk_rq_cur_sectors(rq); cnt++) {
1357 #ifdef DEBUG
1358 		printk("fd: sector %ld + %d requested for %s\n",
1359 		       blk_rq_pos(rq), cnt,
1360 		       (rq_data_dir(rq) == READ) ? "read" : "write");
1361 #endif
1362 		block = blk_rq_pos(rq) + cnt;
1363 		if ((int)block > floppy->blocks) {
1364 			err = -EIO;
1365 			break;
1366 		}
1367 
1368 		track = block / (floppy->dtype->sects * floppy->type->sect_mult);
1369 		sector = block % (floppy->dtype->sects * floppy->type->sect_mult);
1370 		data = rq->buffer + 512 * cnt;
1371 #ifdef DEBUG
1372 		printk("access to track %d, sector %d, with buffer at "
1373 		       "0x%08lx\n", track, sector, data);
1374 #endif
1375 
1376 		if (get_track(drive, track) == -1) {
1377 			err = -EIO;
1378 			break;
1379 		}
1380 
1381 		if (rq_data_dir(rq) == READ) {
1382 			memcpy(data, floppy->trackbuf + sector * 512, 512);
1383 		} else {
1384 			memcpy(floppy->trackbuf + sector * 512, data, 512);
1385 
1386 			/* keep the drive spinning while writes are scheduled */
1387 			if (!fd_motor_on(drive)) {
1388 				err = -EIO;
1389 				break;
1390 			}
1391 			/*
1392 			 * setup a callback to write the track buffer
1393 			 * after a short (1 tick) delay.
1394 			 */
1395 			local_irq_save(flags);
1396 
1397 			floppy->dirty = 1;
1398 		        /* reset the timer */
1399 			mod_timer (flush_track_timer + drive, jiffies + 1);
1400 			local_irq_restore(flags);
1401 		}
1402 	}
1403 
1404 	if (__blk_end_request_cur(rq, err))
1405 		goto next_segment;
1406 	goto next_req;
1407 }
1408 
1409 static void do_fd_request(struct request_queue * q)
1410 {
1411 	redo_fd_request();
1412 }
1413 
1414 static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1415 {
1416 	int drive = MINOR(bdev->bd_dev) & 3;
1417 
1418 	geo->heads = unit[drive].type->heads;
1419 	geo->sectors = unit[drive].dtype->sects * unit[drive].type->sect_mult;
1420 	geo->cylinders = unit[drive].type->tracks;
1421 	return 0;
1422 }
1423 
1424 static int fd_ioctl(struct block_device *bdev, fmode_t mode,
1425 		    unsigned int cmd, unsigned long param)
1426 {
1427 	struct amiga_floppy_struct *p = bdev->bd_disk->private_data;
1428 	int drive = p - unit;
1429 	static struct floppy_struct getprm;
1430 	void __user *argp = (void __user *)param;
1431 
1432 	switch(cmd){
1433 	case FDFMTBEG:
1434 		get_fdc(drive);
1435 		if (fd_ref[drive] > 1) {
1436 			rel_fdc();
1437 			return -EBUSY;
1438 		}
1439 		fsync_bdev(bdev);
1440 		if (fd_motor_on(drive) == 0) {
1441 			rel_fdc();
1442 			return -ENODEV;
1443 		}
1444 		if (fd_calibrate(drive) == 0) {
1445 			rel_fdc();
1446 			return -ENXIO;
1447 		}
1448 		floppy_off(drive);
1449 		rel_fdc();
1450 		break;
1451 	case FDFMTTRK:
1452 		if (param < p->type->tracks * p->type->heads)
1453 		{
1454 			get_fdc(drive);
1455 			if (fd_seek(drive,param) != 0){
1456 				memset(p->trackbuf, FD_FILL_BYTE,
1457 				       p->dtype->sects * p->type->sect_mult * 512);
1458 				non_int_flush_track(drive);
1459 			}
1460 			floppy_off(drive);
1461 			rel_fdc();
1462 		}
1463 		else
1464 			return -EINVAL;
1465 		break;
1466 	case FDFMTEND:
1467 		floppy_off(drive);
1468 		invalidate_bdev(bdev);
1469 		break;
1470 	case FDGETPRM:
1471 		memset((void *)&getprm, 0, sizeof (getprm));
1472 		getprm.track=p->type->tracks;
1473 		getprm.head=p->type->heads;
1474 		getprm.sect=p->dtype->sects * p->type->sect_mult;
1475 		getprm.size=p->blocks;
1476 		if (copy_to_user(argp, &getprm, sizeof(struct floppy_struct)))
1477 			return -EFAULT;
1478 		break;
1479 	case FDSETPRM:
1480 	case FDDEFPRM:
1481 		return -EINVAL;
1482 	case FDFLUSH: /* unconditionally, even if not needed */
1483 		del_timer (flush_track_timer + drive);
1484 		non_int_flush_track(drive);
1485 		break;
1486 #ifdef RAW_IOCTL
1487 	case IOCTL_RAW_TRACK:
1488 		if (copy_to_user(argp, raw_buf, p->type->read_size))
1489 			return -EFAULT;
1490 		else
1491 			return p->type->read_size;
1492 #endif
1493 	default:
1494 		printk(KERN_DEBUG "fd_ioctl: unknown cmd %d for drive %d.",
1495 		       cmd, drive);
1496 		return -ENOSYS;
1497 	}
1498 	return 0;
1499 }
1500 
1501 static void fd_probe(int dev)
1502 {
1503 	unsigned long code;
1504 	int type;
1505 	int drive;
1506 
1507 	drive = dev & 3;
1508 	code = fd_get_drive_id(drive);
1509 
1510 	/* get drive type */
1511 	for (type = 0; type < num_dr_types; type++)
1512 		if (drive_types[type].code == code)
1513 			break;
1514 
1515 	if (type >= num_dr_types) {
1516 		printk(KERN_WARNING "fd_probe: unsupported drive type "
1517 		       "%08lx found\n", code);
1518 		unit[drive].type = &drive_types[num_dr_types-1]; /* FD_NODRIVE */
1519 		return;
1520 	}
1521 
1522 	unit[drive].type = drive_types + type;
1523 	unit[drive].track = -1;
1524 
1525 	unit[drive].disk = -1;
1526 	unit[drive].motor = 0;
1527 	unit[drive].busy = 0;
1528 	unit[drive].status = -1;
1529 }
1530 
1531 /*
1532  * floppy_open check for aliasing (/dev/fd0 can be the same as
1533  * /dev/PS0 etc), and disallows simultaneous access to the same
1534  * drive with different device numbers.
1535  */
1536 static int floppy_open(struct block_device *bdev, fmode_t mode)
1537 {
1538 	int drive = MINOR(bdev->bd_dev) & 3;
1539 	int system =  (MINOR(bdev->bd_dev) & 4) >> 2;
1540 	int old_dev;
1541 	unsigned long flags;
1542 
1543 	old_dev = fd_device[drive];
1544 
1545 	if (fd_ref[drive] && old_dev != system)
1546 		return -EBUSY;
1547 
1548 	if (mode & (FMODE_READ|FMODE_WRITE)) {
1549 		check_disk_change(bdev);
1550 		if (mode & FMODE_WRITE) {
1551 			int wrprot;
1552 
1553 			get_fdc(drive);
1554 			fd_select (drive);
1555 			wrprot = !(ciaa.pra & DSKPROT);
1556 			fd_deselect (drive);
1557 			rel_fdc();
1558 
1559 			if (wrprot)
1560 				return -EROFS;
1561 		}
1562 	}
1563 
1564 	local_irq_save(flags);
1565 	fd_ref[drive]++;
1566 	fd_device[drive] = system;
1567 	local_irq_restore(flags);
1568 
1569 	unit[drive].dtype=&data_types[system];
1570 	unit[drive].blocks=unit[drive].type->heads*unit[drive].type->tracks*
1571 		data_types[system].sects*unit[drive].type->sect_mult;
1572 	set_capacity(unit[drive].gendisk, unit[drive].blocks);
1573 
1574 	printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
1575 	       unit[drive].type->name, data_types[system].name);
1576 
1577 	return 0;
1578 }
1579 
1580 static int floppy_release(struct gendisk *disk, fmode_t mode)
1581 {
1582 	struct amiga_floppy_struct *p = disk->private_data;
1583 	int drive = p - unit;
1584 
1585 	if (unit[drive].dirty == 1) {
1586 		del_timer (flush_track_timer + drive);
1587 		non_int_flush_track (drive);
1588 	}
1589 
1590 	if (!fd_ref[drive]--) {
1591 		printk(KERN_CRIT "floppy_release with fd_ref == 0");
1592 		fd_ref[drive] = 0;
1593 	}
1594 #ifdef MODULE
1595 /* the mod_use counter is handled this way */
1596 	floppy_off (drive | 0x40000000);
1597 #endif
1598 	return 0;
1599 }
1600 
1601 /*
1602  * floppy-change is never called from an interrupt, so we can relax a bit
1603  * here, sleep etc. Note that floppy-on tries to set current_DOR to point
1604  * to the desired drive, but it will probably not survive the sleep if
1605  * several floppies are used at the same time: thus the loop.
1606  */
1607 static int amiga_floppy_change(struct gendisk *disk)
1608 {
1609 	struct amiga_floppy_struct *p = disk->private_data;
1610 	int drive = p - unit;
1611 	int changed;
1612 	static int first_time = 1;
1613 
1614 	if (first_time)
1615 		changed = first_time--;
1616 	else {
1617 		get_fdc(drive);
1618 		fd_select (drive);
1619 		changed = !(ciaa.pra & DSKCHANGE);
1620 		fd_deselect (drive);
1621 		rel_fdc();
1622 	}
1623 
1624 	if (changed) {
1625 		fd_probe(drive);
1626 		p->track = -1;
1627 		p->dirty = 0;
1628 		writepending = 0; /* if this was true before, too bad! */
1629 		writefromint = 0;
1630 		return 1;
1631 	}
1632 	return 0;
1633 }
1634 
1635 static const struct block_device_operations floppy_fops = {
1636 	.owner		= THIS_MODULE,
1637 	.open		= floppy_open,
1638 	.release	= floppy_release,
1639 	.locked_ioctl	= fd_ioctl,
1640 	.getgeo		= fd_getgeo,
1641 	.media_changed	= amiga_floppy_change,
1642 };
1643 
1644 static int __init fd_probe_drives(void)
1645 {
1646 	int drive,drives,nomem;
1647 
1648 	printk(KERN_INFO "FD: probing units\nfound ");
1649 	drives=0;
1650 	nomem=0;
1651 	for(drive=0;drive<FD_MAX_UNITS;drive++) {
1652 		struct gendisk *disk;
1653 		fd_probe(drive);
1654 		if (unit[drive].type->code == FD_NODRIVE)
1655 			continue;
1656 		disk = alloc_disk(1);
1657 		if (!disk) {
1658 			unit[drive].type->code = FD_NODRIVE;
1659 			continue;
1660 		}
1661 		unit[drive].gendisk = disk;
1662 		drives++;
1663 		if ((unit[drive].trackbuf = kmalloc(FLOPPY_MAX_SECTORS * 512, GFP_KERNEL)) == NULL) {
1664 			printk("no mem for ");
1665 			unit[drive].type = &drive_types[num_dr_types - 1]; /* FD_NODRIVE */
1666 			drives--;
1667 			nomem = 1;
1668 		}
1669 		printk("fd%d ",drive);
1670 		disk->major = FLOPPY_MAJOR;
1671 		disk->first_minor = drive;
1672 		disk->fops = &floppy_fops;
1673 		sprintf(disk->disk_name, "fd%d", drive);
1674 		disk->private_data = &unit[drive];
1675 		disk->queue = floppy_queue;
1676 		set_capacity(disk, 880*2);
1677 		add_disk(disk);
1678 	}
1679 	if ((drives > 0) || (nomem == 0)) {
1680 		if (drives == 0)
1681 			printk("no drives");
1682 		printk("\n");
1683 		return drives;
1684 	}
1685 	printk("\n");
1686 	return -ENOMEM;
1687 }
1688 
1689 static struct kobject *floppy_find(dev_t dev, int *part, void *data)
1690 {
1691 	int drive = *part & 3;
1692 	if (unit[drive].type->code == FD_NODRIVE)
1693 		return NULL;
1694 	*part = 0;
1695 	return get_disk(unit[drive].gendisk);
1696 }
1697 
1698 static int __init amiga_floppy_init(void)
1699 {
1700 	int i, ret;
1701 
1702 	if (!MACH_IS_AMIGA)
1703 		return -ENODEV;
1704 
1705 	if (!AMIGAHW_PRESENT(AMI_FLOPPY))
1706 		return -ENODEV;
1707 
1708 	if (register_blkdev(FLOPPY_MAJOR,"fd"))
1709 		return -EBUSY;
1710 
1711 	/*
1712 	 *  We request DSKPTR, DSKLEN and DSKDATA only, because the other
1713 	 *  floppy registers are too spreaded over the custom register space
1714 	 */
1715 	ret = -EBUSY;
1716 	if (!request_mem_region(CUSTOM_PHYSADDR+0x20, 8, "amiflop [Paula]")) {
1717 		printk("fd: cannot get floppy registers\n");
1718 		goto out_blkdev;
1719 	}
1720 
1721 	ret = -ENOMEM;
1722 	if ((raw_buf = (char *)amiga_chip_alloc (RAW_BUF_SIZE, "Floppy")) ==
1723 	    NULL) {
1724 		printk("fd: cannot get chip mem buffer\n");
1725 		goto out_memregion;
1726 	}
1727 
1728 	ret = -EBUSY;
1729 	if (request_irq(IRQ_AMIGA_DSKBLK, fd_block_done, 0, "floppy_dma", NULL)) {
1730 		printk("fd: cannot get irq for dma\n");
1731 		goto out_irq;
1732 	}
1733 
1734 	if (request_irq(IRQ_AMIGA_CIAA_TB, ms_isr, 0, "floppy_timer", NULL)) {
1735 		printk("fd: cannot get irq for timer\n");
1736 		goto out_irq2;
1737 	}
1738 
1739 	ret = -ENOMEM;
1740 	floppy_queue = blk_init_queue(do_fd_request, &amiflop_lock);
1741 	if (!floppy_queue)
1742 		goto out_queue;
1743 
1744 	ret = -ENODEV;
1745 	if (fd_probe_drives() < 1) /* No usable drives */
1746 		goto out_probe;
1747 
1748 	blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
1749 				floppy_find, NULL, NULL);
1750 
1751 	/* initialize variables */
1752 	init_timer(&motor_on_timer);
1753 	motor_on_timer.expires = 0;
1754 	motor_on_timer.data = 0;
1755 	motor_on_timer.function = motor_on_callback;
1756 	for (i = 0; i < FD_MAX_UNITS; i++) {
1757 		init_timer(&motor_off_timer[i]);
1758 		motor_off_timer[i].expires = 0;
1759 		motor_off_timer[i].data = i|0x80000000;
1760 		motor_off_timer[i].function = fd_motor_off;
1761 		init_timer(&flush_track_timer[i]);
1762 		flush_track_timer[i].expires = 0;
1763 		flush_track_timer[i].data = i;
1764 		flush_track_timer[i].function = flush_track_callback;
1765 
1766 		unit[i].track = -1;
1767 	}
1768 
1769 	init_timer(&post_write_timer);
1770 	post_write_timer.expires = 0;
1771 	post_write_timer.data = 0;
1772 	post_write_timer.function = post_write;
1773 
1774 	for (i = 0; i < 128; i++)
1775 		mfmdecode[i]=255;
1776 	for (i = 0; i < 16; i++)
1777 		mfmdecode[mfmencode[i]]=i;
1778 
1779 	/* make sure that disk DMA is enabled */
1780 	custom.dmacon = DMAF_SETCLR | DMAF_DISK;
1781 
1782 	/* init ms timer */
1783 	ciaa.crb = 8; /* one-shot, stop */
1784 	return 0;
1785 
1786 out_probe:
1787 	blk_cleanup_queue(floppy_queue);
1788 out_queue:
1789 	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1790 out_irq2:
1791 	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1792 out_irq:
1793 	amiga_chip_free(raw_buf);
1794 out_memregion:
1795 	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1796 out_blkdev:
1797 	unregister_blkdev(FLOPPY_MAJOR,"fd");
1798 	return ret;
1799 }
1800 
1801 module_init(amiga_floppy_init);
1802 #ifdef MODULE
1803 
1804 #if 0 /* not safe to unload */
1805 void cleanup_module(void)
1806 {
1807 	int i;
1808 
1809 	for( i = 0; i < FD_MAX_UNITS; i++) {
1810 		if (unit[i].type->code != FD_NODRIVE) {
1811 			del_gendisk(unit[i].gendisk);
1812 			put_disk(unit[i].gendisk);
1813 			kfree(unit[i].trackbuf);
1814 		}
1815 	}
1816 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
1817 	free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1818 	free_irq(IRQ_AMIGA_DSKBLK, NULL);
1819 	custom.dmacon = DMAF_DISK; /* disable DMA */
1820 	amiga_chip_free(raw_buf);
1821 	blk_cleanup_queue(floppy_queue);
1822 	release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1823 	unregister_blkdev(FLOPPY_MAJOR, "fd");
1824 }
1825 #endif
1826 
1827 #else
1828 static int __init amiga_floppy_setup (char *str)
1829 {
1830 	int n;
1831 	if (!MACH_IS_AMIGA)
1832 		return 0;
1833 	if (!get_option(&str, &n))
1834 		return 0;
1835 	printk (KERN_INFO "amiflop: Setting default df0 to %x\n", n);
1836 	fd_def_df0 = n;
1837 	return 1;
1838 }
1839 
1840 __setup("floppy=", amiga_floppy_setup);
1841 #endif
1842