9c6e5b0fe894f9e6af94a50b87a2ec2b2f04a470
[linux-2.6.git] / drivers / block / amiflop.c
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 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\n" KERN_INFO "found ");
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