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