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
  68 #include <asm/setup.h>
  69 #include <asm/uaccess.h>
  70 #include <asm/amigahw.h>
  71 #include <asm/amigaints.h>
  72 #include <asm/irq.h>
  73
  74 #undef DEBUG /* print _LOTS_ of infos */
  75
  76 #define RAW_IOCTL
  77 #ifdef RAW_IOCTL
  78 #define IOCTL_RAW_TRACK 0x5254524B  /* 'RTRK' */
  79 #endif
  80
  81 /*
  82  *  Defines
  83  */
  84
  85 /*
  86  *  Error codes
  87  */
  88 #define FD_OK           0       /* operation succeeded */
  89 #define FD_ERROR        -1      /* general error (seek, read, write, etc) */
  90 #define FD_NOUNIT       1       /* unit does not exist */
  91 #define FD_UNITBUSY     2       /* unit already active */
  92 #define FD_NOTACTIVE    3       /* unit is not active */
  93 #define FD_NOTREADY     4       /* unit is not ready (motor not on/no disk) */
  94
  95 #define MFM_NOSYNC      1
  96 #define MFM_HEADER      2
  97 #define MFM_DATA        3
  98 #define MFM_TRACK       4
  99
 100 /*
 101  *  Floppy ID values
 102  */
 103 #define FD_NODRIVE      0x00000000  /* response when no unit is present */
 104 #define FD_DD_3         0xffffffff  /* double-density 3.5" (880K) drive */
 105 #define FD_HD_3         0x55555555  /* high-density 3.5" (1760K) drive */
 106 #define FD_DD_5         0xaaaaaaaa  /* double-density 5.25" (440K) drive */
 107
 108 static unsigned long int fd_def_df0 = FD_DD_3;     /* default for df0 if it doesn't identify */
 109
 110 module_param(fd_def_df0, ulong, 0);
 111 MODULE_LICENSE("GPL");
 112
 113 static struct request_queue *floppy_queue;
 114 #define QUEUE (floppy_queue)
 115 #define CURRENT elv_next_request(floppy_queue)
 116
 117 /*
 118  *  Macros
 119  */
 120 #define MOTOR_ON        (ciab.prb &= ~DSKMOTOR)
 121 #define MOTOR_OFF       (ciab.prb |= DSKMOTOR)
 122 #define SELECT(mask)    (ciab.prb &= ~mask)
 123 #define DESELECT(mask)  (ciab.prb |= mask)
 124 #define SELMASK(drive)  (1 << (3 + (drive & 3)))
 125
 126 static struct fd_drive_type drive_types[] = {
 127 /*  code        name       tr he   rdsz   wrsz sm pc1 pc2 sd  st st*/
 128 /*  warning: times are now in milliseconds (ms)                    */
 129 { FD_DD_3,      "DD 3.5",  80, 2, 14716, 13630, 1, 80,161, 3, 18, 1},
 130 { FD_HD_3,      "HD 3.5",  80, 2, 28344, 27258, 2, 80,161, 3, 18, 1},
 131 { FD_DD_5,      "DD 5.25", 40, 2, 14716, 13630, 1, 40, 81, 6, 30, 2},
 132 { FD_NODRIVE, "No Drive", 0, 0,     0,     0, 0,  0,  0,  0,  0, 0}
 133 };
 134 static int num_dr_types = ARRAY_SIZE(drive_types);
 135
 136 static int amiga_read(int), dos_read(int);
 137 static void amiga_write(int), dos_write(int);
 138 static struct fd_data_type data_types[] = {
 139         { "Amiga", 11 , amiga_read, amiga_write},
 140         { "MS-Dos", 9, dos_read, dos_write}
 141 };
 142
 143 /* current info on each unit */
 144 static struct amiga_floppy_struct unit[FD_MAX_UNITS];
 145
 146 static struct timer_list flush_track_timer[FD_MAX_UNITS];
 147 static struct timer_list post_write_timer;
 148 static struct timer_list motor_on_timer;
 149 static struct timer_list motor_off_timer[FD_MAX_UNITS];
 150 static int on_attempts;
 151
 152 /* Synchronization of FDC access */
 153 /* request loop (trackbuffer) */
 154 static volatile int fdc_busy = -1;
 155 static volatile int fdc_nested;
 156 static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
 157
 158 static DECLARE_WAIT_QUEUE_HEAD(motor_wait);
 159
 160 static volatile int selected = -1;      /* currently selected drive */
 161
 162 static int writepending;
 163 static int writefromint;
 164 static char *raw_buf;
 165
 166 static DEFINE_SPINLOCK(amiflop_lock);
 167
 168 #define RAW_BUF_SIZE 30000  /* size of raw disk data */
 169
 170 /*
 171  * These are global variables, as that's the easiest way to give
 172  * information to interrupts. They are the data used for the current
 173  * request.
 174  */
 175 static volatile char block_flag;
 176 static DECLARE_WAIT_QUEUE_HEAD(wait_fd_block);
 177
 178 /* MS-Dos MFM Coding tables (should go quick and easy) */
 179 static unsigned char mfmencode[16]={
 180         0x2a, 0x29, 0x24, 0x25, 0x12, 0x11, 0x14, 0x15,
 181         0x4a, 0x49, 0x44, 0x45, 0x52, 0x51, 0x54, 0x55
 182 };
 183 static unsigned char mfmdecode[128];
 184
 185 /* floppy internal millisecond timer stuff */
 186 static volatile int ms_busy = -1;
 187 static DECLARE_WAIT_QUEUE_HEAD(ms_wait);
 188 #define MS_TICKS ((amiga_eclock+50)/1000)
 189
 190 /*
 191  * Note that MAX_ERRORS=X doesn't imply that we retry every bad read
 192  * max X times - some types of errors increase the errorcount by 2 or
 193  * even 3, so we might actually retry only X/2 times before giving up.
 194  */
 195 #define MAX_ERRORS 12
 196
 197 #define custom amiga_custom
 198
 199 /* Prevent "aliased" accesses. */
 200 static int fd_ref[4] = { 0,0,0,0 };
 201 static int fd_device[4] = { 0, 0, 0, 0 };
 202
 203 /*
 204  * Here come the actual hardware access and helper functions.
 205  * They are not reentrant and single threaded because all drives
 206  * share the same hardware and the same trackbuffer.
 207  */
 208
 209 /* Milliseconds timer */
 210
 211 static irqreturn_t ms_isr(int irq, void *dummy, struct pt_regs *fp)
 212 {
 213         ms_busy = -1;
 214         wake_up(&ms_wait);
 215         return IRQ_HANDLED;
 216 }
 217
 218 /* all waits are queued up
 219    A more generic routine would do a schedule a la timer.device */
 220 static void ms_delay(int ms)
 221 {
 222         unsigned long flags;
 223         int ticks;
 224         if (ms > 0) {
 225                 local_irq_save(flags);
 226                 while (ms_busy == 0)
 227                         sleep_on(&ms_wait);
 228                 ms_busy = 0;
 229                 local_irq_restore(flags);
 230                 ticks = MS_TICKS*ms-1;
 231                 ciaa.tblo=ticks%256;
 232                 ciaa.tbhi=ticks/256;
 233                 ciaa.crb=0x19; /*count eclock, force load, one-shoot, start */
 234                 sleep_on(&ms_wait);
 235         }
 236 }
 237
 238 /* Hardware semaphore */
 239
 240 /* returns true when we would get the semaphore */
 241 static inline int try_fdc(int drive)
 242 {
 243         drive &= 3;
 244         return ((fdc_busy < 0) || (fdc_busy == drive));
 245 }
 246
 247 static void get_fdc(int drive)
 248 {
 249         unsigned long flags;
 250
 251         drive &= 3;
 252 #ifdef DEBUG
 253         printk("get_fdc: drive %d  fdc_busy %d  fdc_nested %d\n",drive,fdc_busy,fdc_nested);
 254 #endif
 255         local_irq_save(flags);
 256         while (!try_fdc(drive))
 257                 sleep_on(&fdc_wait);
 258         fdc_busy = drive;
 259         fdc_nested++;
 260         local_irq_restore(flags);
 261 }
 262
 263 static inline void rel_fdc(void)
 264 {
 265 #ifdef DEBUG
 266         if (fdc_nested == 0)
 267                 printk("fd: unmatched rel_fdc\n");
 268         printk("rel_fdc: fdc_busy %d fdc_nested %d\n",fdc_busy,fdc_nested);
 269 #endif
 270         fdc_nested--;
 271         if (fdc_nested == 0) {
 272                 fdc_busy = -1;
 273                 wake_up(&fdc_wait);
 274         }
 275 }
 276
 277 static void fd_select (int drive)
 278 {
 279         unsigned char prb = ~0;
 280
 281         drive&=3;
 282 #ifdef DEBUG
 283         printk("selecting %d\n",drive);
 284 #endif
 285         if (drive == selected)
 286                 return;
 287         get_fdc(drive);
 288         selected = drive;
 289
 290         if (unit[drive].track % 2 != 0)
 291                 prb &= ~DSKSIDE;
 292         if (unit[drive].motor == 1)
 293                 prb &= ~DSKMOTOR;
 294         ciab.prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
 295         ciab.prb = prb;
 296         prb &= ~SELMASK(drive);
 297         ciab.prb = prb;
 298         rel_fdc();
 299 }
 300
 301 static void fd_deselect (int drive)
 302 {
 303         unsigned char prb;
 304         unsigned long flags;
 305
 306         drive&=3;
 307 #ifdef DEBUG
 308         printk("deselecting %d\n",drive);
 309 #endif
 310         if (drive != selected) {
 311                 printk(KERN_WARNING "Deselecting drive %d while %d was selected!\n",drive,selected);
 312                 return;
 313         }
 314
 315         get_fdc(drive);
 316         local_irq_save(flags);
 317
 318         selected = -1;
 319
 320         prb = ciab.prb;
 321         prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
 322         ciab.prb = prb;
 323
 324         local_irq_restore (flags);
 325         rel_fdc();
 326
 327 }
 328
 329 static void motor_on_callback(unsigned long nr)
 330 {
 331         if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
 332                 wake_up (&motor_wait);
 333         } else {
 334                 motor_on_timer.expires = jiffies + HZ/10;
 335                 add_timer(&motor_on_timer);
 336         }
 337 }
 338
 339 static int fd_motor_on(int nr)
 340 {
 341         nr &= 3;
 342
 343         del_timer(motor_off_timer + nr);
 344
 345         if (!unit[nr].motor) {
 346                 unit[nr].motor = 1;
 347                 fd_select(nr);
 348
 349                 motor_on_timer.data = nr;
 350                 mod_timer(&motor_on_timer, jiffies + HZ/2);
 351
 352                 on_attempts = 10;
 353                 sleep_on (&motor_wait);
 354                 fd_deselect(nr);
 355         }
 356
 357         if (on_attempts == 0) {
 358                 on_attempts = -1;
 359 #if 0
 360                 printk (KERN_ERR "motor_on failed, turning motor off\n");
 361                 fd_motor_off (nr);
 362                 return 0;
 363 #else
 364                 printk (KERN_WARNING "DSKRDY not set after 1.5 seconds - assuming drive is spinning notwithstanding\n");
 365 #endif
 366         }
 367
 368         return 1;
 369 }
 370
 371 static void fd_motor_off(unsigned long drive)
 372 {
 373         long calledfromint;
 374 #ifdef MODULE
 375         long decusecount;
 376
 377         decusecount = drive & 0x40000000;
 378 #endif
 379         calledfromint = drive & 0x80000000;
 380         drive&=3;
 381         if (calledfromint && !try_fdc(drive)) {
 382                 /* We would be blocked in an interrupt, so try again later */
 383                 motor_off_timer[drive].expires = jiffies + 1;
 384                 add_timer(motor_off_timer + drive);
 385                 return;
 386         }
 387         unit[drive].motor = 0;
 388         fd_select(drive);
 389         udelay (1);
 390         fd_deselect(drive);
 391 }
 392
 393 static void floppy_off (unsigned int nr)
 394 {
 395         int drive;
 396
 397         drive = nr & 3;
 398         /* called this way it is always from interrupt */
 399         motor_off_timer[drive].data = nr | 0x80000000;
 400         mod_timer(motor_off_timer + drive, jiffies + 3*HZ);
 401 }
 402
 403 static int fd_calibrate(int drive)
 404 {
 405         unsigned char prb;
 406         int n;
 407
 408         drive &= 3;
 409         get_fdc(drive);
 410         if (!fd_motor_on (drive))
 411                 return 0;
 412         fd_select (drive);
 413         prb = ciab.prb;
 414         prb |= DSKSIDE;
 415         prb &= ~DSKDIREC;
 416         ciab.prb = prb;
 417         for (n = unit[drive].type->tracks/2; n != 0; --n) {
 418                 if (ciaa.pra & DSKTRACK0)
 419                         break;
 420                 prb &= ~DSKSTEP;
 421                 ciab.prb = prb;
 422                 prb |= DSKSTEP;
 423                 udelay (2);
 424                 ciab.prb = prb;
 425                 ms_delay(unit[drive].type->step_delay);
 426         }
 427         ms_delay (unit[drive].type->settle_time);
 428         prb |= DSKDIREC;
 429         n = unit[drive].type->tracks + 20;
 430         for (;;) {
 431                 prb &= ~DSKSTEP;
 432                 ciab.prb = prb;
 433                 prb |= DSKSTEP;
 434                 udelay (2);
 435                 ciab.prb = prb;
 436                 ms_delay(unit[drive].type->step_delay + 1);
 437                 if ((ciaa.pra & DSKTRACK0) == 0)
 438                         break;
 439                 if (--n == 0) {
 440                         printk (KERN_ERR "fd%d: calibrate failed, turning motor off\n", drive);
 441                         fd_motor_off (drive);
 442                         unit[drive].track = -1;
 443                         rel_fdc();
 444                         return 0;
 445                 }
 446         }
 447         unit[drive].track = 0;
 448         ms_delay(unit[drive].type->settle_time);
 449
 450         rel_fdc();
 451         fd_deselect(drive);
 452         return 1;
 453 }
 454
 455 static int fd_seek(int drive, int track)
 456 {
 457         unsigned char prb;
 458         int cnt;
 459
 460 #ifdef DEBUG
 461         printk("seeking drive %d to track %d\n",drive,track);
 462 #endif
 463         drive &= 3;
 464         get_fdc(drive);
 465         if (unit[drive].track == track) {
 466                 rel_fdc();
 467                 return 1;
 468         }
 469         if (!fd_motor_on(drive)) {
 470                 rel_fdc();
 471                 return 0;
 472         }
 473         if (unit[drive].track < 0 && !fd_calibrate(drive)) {
 474                 rel_fdc();
 475                 return 0;
 476         }
 477
 478         fd_select (drive);
 479         cnt = unit[drive].track/2 - track/2;
 480         prb = ciab.prb;
 481         prb |= DSKSIDE | DSKDIREC;
 482         if (track % 2 != 0)
 483                 prb &= ~DSKSIDE;
 484         if (cnt < 0) {
 485                 cnt = - cnt;
 486                 prb &= ~DSKDIREC;
 487         }
 488         ciab.prb = prb;
 489         if (track % 2 != unit[drive].track % 2)
 490                 ms_delay (unit[drive].type->side_time);
 491         unit[drive].track = track;
 492         if (cnt == 0) {
 493                 rel_fdc();
 494                 fd_deselect(drive);
 495                 return 1;
 496         }
 497         do {
 498                 prb &= ~DSKSTEP;
 499                 ciab.prb = prb;
 500                 prb |= DSKSTEP;
 501                 udelay (1);
 502                 ciab.prb = prb;
 503                 ms_delay (unit[drive].type->step_delay);
 504         } while (--cnt != 0);
 505         ms_delay (unit[drive].type->settle_time);
 506
 507         rel_fdc();
 508         fd_deselect(drive);
 509         return 1;
 510 }
 511
 512 static unsigned long fd_get_drive_id(int drive)
 513 {
 514         int i;
 515         ulong id = 0;
 516
 517         drive&=3;
 518         get_fdc(drive);
 519         /* set up for ID */
 520         MOTOR_ON;
 521         udelay(2);
 522         SELECT(SELMASK(drive));
 523         udelay(2);
 524         DESELECT(SELMASK(drive));
 525         udelay(2);
 526         MOTOR_OFF;
 527         udelay(2);
 528         SELECT(SELMASK(drive));
 529         udelay(2);
 530         DESELECT(SELMASK(drive));
 531         udelay(2);
 532
 533         /* loop and read disk ID */
 534         for (i=0; i<32; i++) {
 535                 SELECT(SELMASK(drive));
 536                 udelay(2);
 537
 538                 /* read and store value of DSKRDY */
 539                 id <<= 1;
 540                 id |= (ciaa.pra & DSKRDY) ? 0 : 1;      /* cia regs are low-active! */
 541
 542                 DESELECT(SELMASK(drive));
 543         }
 544
 545         rel_fdc();
 546
 547         /*
 548          * RB: At least A500/A2000's df0: don't identify themselves.
 549          * As every (real) Amiga has at least a 3.5" DD drive as df0:
 550          * we default to that if df0: doesn't identify as a certain
 551          * type.
 552          */
 553         if(drive == 0 && id == FD_NODRIVE)
 554         {
 555                 id = fd_def_df0;
 556                 printk(KERN_NOTICE "fd: drive 0 didn't identify, setting default %08lx\n", (ulong)fd_def_df0);
 557         }
 558         /* return the ID value */
 559         return (id);
 560 }
 561
 562 static irqreturn_t fd_block_done(int irq, void *dummy, struct pt_regs *fp)
 563 {
 564         if (block_flag)
 565                 custom.dsklen = 0x4000;
 566
 567         if (block_flag == 2) { /* writing */
 568                 writepending = 2;
 569                 post_write_timer.expires = jiffies + 1; /* at least 2 ms */
 570                 post_write_timer.data = selected;
 571                 add_timer(&post_write_timer);
 572         }
 573         else {                /* reading */
 574                 block_flag = 0;
 575                 wake_up (&wait_fd_block);
 576         }
 577         return IRQ_HANDLED;
 578 }
 579
 580 static void raw_read(int drive)
 581 {
 582         drive&=3;
 583         get_fdc(drive);
 584         while (block_flag)
 585                 sleep_on(&wait_fd_block);
 586         fd_select(drive);
 587         /* setup adkcon bits correctly */
 588         custom.adkcon = ADK_MSBSYNC;
 589         custom.adkcon = ADK_SETCLR|ADK_WORDSYNC|ADK_FAST;
 590
 591         custom.dsksync = MFM_SYNC;
 592
 593         custom.dsklen = 0;
 594         custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
 595         custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
 596         custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
 597
 598         block_flag = 1;
 599
 600         while (block_flag)
 601                 sleep_on (&wait_fd_block);
 602
 603         custom.dsklen = 0;
 604         fd_deselect(drive);
 605         rel_fdc();
 606 }
 607
 608 static int raw_write(int drive)
 609 {
 610         ushort adk;
 611
 612         drive&=3;
 613         get_fdc(drive); /* corresponds to rel_fdc() in post_write() */
 614         if ((ciaa.pra & DSKPROT) == 0) {
 615                 rel_fdc();
 616                 return 0;
 617         }
 618         while (block_flag)
 619                 sleep_on(&wait_fd_block);
 620         fd_select(drive);
 621         /* clear adkcon bits */
 622         custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
 623         /* set appropriate adkcon bits */
 624         adk = ADK_SETCLR|ADK_FAST;
 625         if ((ulong)unit[drive].track >= unit[drive].type->precomp2)
 626                 adk |= ADK_PRECOMP1;
 627         else if ((ulong)unit[drive].track >= unit[drive].type->precomp1)
 628                 adk |= ADK_PRECOMP0;
 629         custom.adkcon = adk;
 630
 631         custom.dsklen = DSKLEN_WRITE;
 632         custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
 633         custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
 634         custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
 635
 636         block_flag = 2;
 637         return 1;
 638 }
 639
 640 /*
 641  * to be called at least 2ms after the write has finished but before any
 642  * other access to the hardware.
 643  */
 644 static void post_write (unsigned long drive)
 645 {
 646 #ifdef DEBUG
 647         printk("post_write for drive %ld\n",drive);
 648 #endif
 649         drive &= 3;
 650         custom.dsklen = 0;
 651         block_flag = 0;
 652         writepending = 0;
 653         writefromint = 0;
 654         unit[drive].dirty = 0;
 655         wake_up(&wait_fd_block);
 656         fd_deselect(drive);
 657         rel_fdc(); /* corresponds to get_fdc() in raw_write */
 658 }
 659
 660
 661 /*
 662  * The following functions are to convert the block contents into raw data
 663  * written to disk and vice versa.
 664  * (Add other formats here ;-))
 665  */
 666
 667 static unsigned long scan_sync(unsigned long raw, unsigned long end)
 668 {
 669         ushort *ptr = (ushort *)raw, *endp = (ushort *)end;
 670
 671         while (ptr < endp && *ptr++ != 0x4489)
 672                 ;
 673         if (ptr < endp) {
 674                 while (*ptr == 0x4489 && ptr < endp)
 675                         ptr++;
 676                 return (ulong)ptr;
 677         }
 678         return 0;
 679 }
 680
 681 static inline unsigned long checksum(unsigned long *addr, int len)
 682 {
 683         unsigned long csum = 0;
 684
 685         len /= sizeof(*addr);
 686         while (len-- > 0)
 687                 csum ^= *addr++;
 688         csum = ((csum>>1) & 0x55555555)  ^  (csum & 0x55555555);
 689
 690         return csum;
 691 }
 692
 693 static unsigned long decode (unsigned long *data, unsigned long *raw,
 694                              int len)
 695 {
 696         ulong *odd, *even;
 697
 698         /* convert length from bytes to longwords */
 699         len >>= 2;
 700         odd = raw;
 701         even = odd + len;
 702
 703         /* prepare return pointer */
 704         raw += len * 2;
 705
 706         do {
 707                 *data++ = ((*odd++ & 0x55555555) << 1) | (*even++ & 0x55555555);
 708         } while (--len != 0);
 709
 710         return (ulong)raw;
 711 }
 712
 713 struct header {
 714         unsigned char magic;
 715         unsigned char track;
 716         unsigned char sect;
 717         unsigned char ord;
 718         unsigned char labels[16];
 719         unsigned long hdrchk;
 720         unsigned long datachk;
 721 };
 722
 723 static int amiga_read(int drive)
 724 {
 725         unsigned long raw;
 726         unsigned long end;
 727         int scnt;
 728         unsigned long csum;
 729         struct header hdr;
 730
 731         drive&=3;
 732         raw = (long) raw_buf;
 733         end = raw + unit[drive].type->read_size;
 734
 735         for (scnt = 0;scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
 736                 if (!(raw = scan_sync(raw, end))) {
 737                         printk (KERN_INFO "can't find sync for sector %d\n", scnt);
 738                         return MFM_NOSYNC;
 739                 }
 740
 741                 raw = decode ((ulong *)&hdr.magic, (ulong *)raw, 4);
 742                 raw = decode ((ulong *)&hdr.labels, (ulong *)raw, 16);
 743                 raw = decode ((ulong *)&hdr.hdrchk, (ulong *)raw, 4);
 744                 raw = decode ((ulong *)&hdr.datachk, (ulong *)raw, 4);
 745                 csum = checksum((ulong *)&hdr,
 746                                 (char *)&hdr.hdrchk-(char *)&hdr);
 747
 748 #ifdef DEBUG
 749                 printk ("(%x,%d,%d,%d) (%lx,%lx,%lx,%lx) %lx %lx\n",
 750                         hdr.magic, hdr.track, hdr.sect, hdr.ord,
 751                         *(ulong *)&hdr.labels[0], *(ulong *)&hdr.labels[4],
 752                         *(ulong *)&hdr.labels[8], *(ulong *)&hdr.labels[12],
 753                         hdr.hdrchk, hdr.datachk);
 754 #endif
 755
 756                 if (hdr.hdrchk != csum) {
 757                         printk(KERN_INFO "MFM_HEADER: %08lx,%08lx\n", hdr.hdrchk, csum);
 758                         return MFM_HEADER;
 759                 }
 760
 761                 /* verify track */
 762                 if (hdr.track != unit[drive].track) {
 763                         printk(KERN_INFO "MFM_TRACK: %d, %d\n", hdr.track, unit[drive].track);
 764                         return MFM_TRACK;
 765                 }
 766
 767                 raw = decode ((ulong *)(unit[drive].trackbuf + hdr.sect*512),
 768                               (ulong *)raw, 512);
 769                 csum = checksum((ulong *)(unit[drive].trackbuf + hdr.sect*512), 512);
 770
 771                 if (hdr.datachk != csum) {
 772                         printk(KERN_INFO "MFM_DATA: (%x:%d:%d:%d) sc=%d %lx, %lx\n",
 773                                hdr.magic, hdr.track, hdr.sect, hdr.ord, scnt,
 774                                hdr.datachk, csum);
 775                         printk (KERN_INFO "data=(%lx,%lx,%lx,%lx)\n",
 776                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[0],
 777                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[1],
 778                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[2],
 779                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[3]);
 780                         return MFM_DATA;
 781                 }
 782         }
 783
 784         return 0;
 785 }
 786
 787 static void encode(unsigned long data, unsigned long *dest)
 788 {
 789         unsigned long data2;
 790
 791         data &= 0x55555555;
 792         data2 = data ^ 0x55555555;
 793         data |= ((data2 >> 1) | 0x80000000) & (data2 << 1);
 794
 795         if (*(dest - 1) & 0x00000001)
 796                 data &= 0x7FFFFFFF;
 797
 798         *dest = data;
 799 }
 800
 801 static void encode_block(unsigned long *dest, unsigned long *src, int len)
 802 {
 803         int cnt, to_cnt = 0;
 804         unsigned long data;
 805
 806         /* odd bits */
 807         for (cnt = 0; cnt < len / 4; cnt++) {
 808                 data = src[cnt] >> 1;
 809                 encode(data, dest + to_cnt++);
 810         }
 811
 812         /* even bits */
 813         for (cnt = 0; cnt < len / 4; cnt++) {
 814                 data = src[cnt];
 815                 encode(data, dest + to_cnt++);
 816         }
 817 }
 818
 819 static unsigned long *putsec(int disk, unsigned long *raw, int cnt)
 820 {
 821         struct header hdr;
 822         int i;
 823
 824         disk&=3;
 825         *raw = (raw[-1]&1) ? 0x2AAAAAAA : 0xAAAAAAAA;
 826         raw++;
 827         *raw++ = 0x44894489;
 828
 829         hdr.magic = 0xFF;
 830         hdr.track = unit[disk].track;
 831         hdr.sect = cnt;
 832         hdr.ord = unit[disk].dtype->sects * unit[disk].type->sect_mult - cnt;
 833         for (i = 0; i < 16; i++)
 834                 hdr.labels[i] = 0;
 835         hdr.hdrchk = checksum((ulong *)&hdr,
 836                               (char *)&hdr.hdrchk-(char *)&hdr);
 837         hdr.datachk = checksum((ulong *)(unit[disk].trackbuf+cnt*512), 512);
 838
 839         encode_block(raw, (ulong *)&hdr.magic, 4);
 840         raw += 2;
 841         encode_block(raw, (ulong *)&hdr.labels, 16);
 842         raw += 8;
 843         encode_block(raw, (ulong *)&hdr.hdrchk, 4);
 844         raw += 2;
 845         encode_block(raw, (ulong *)&hdr.datachk, 4);
 846         raw += 2;
 847         encode_block(raw, (ulong *)(unit[disk].trackbuf+cnt*512), 512);
 848         raw += 256;
 849
 850         return raw;
 851 }
 852
 853 static void amiga_write(int disk)
 854 {
 855         unsigned int cnt;
 856         unsigned long *ptr = (unsigned long *)raw_buf;
 857
 858         disk&=3;
 859         /* gap space */
 860         for (cnt = 0; cnt < 415 * unit[disk].type->sect_mult; cnt++)
 861                 *ptr++ = 0xaaaaaaaa;
 862
 863         /* sectors */
 864         for (cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
 865                 ptr = putsec (disk, ptr, cnt);
 866         *(ushort *)ptr = (ptr[-1]&1) ? 0x2AA8 : 0xAAA8;
 867 }
 868
 869
 870 struct dos_header {
 871         unsigned char track,   /* 0-80 */
 872                 side,    /* 0-1 */
 873                 sec,     /* 0-...*/
 874                 len_desc;/* 2 */
 875         unsigned short crc;     /* on 68000 we got an alignment problem,
 876                                    but this compiler solves it  by adding silently
 877                                    adding a pad byte so data won't fit
 878                                    and this took about 3h to discover.... */
 879         unsigned char gap1[22];     /* for longword-alignedness (0x4e) */
 880 };
 881
 882 /* crc routines are borrowed from the messydos-handler  */
 883
 884 /* excerpt from the messydos-device
 885 ; The CRC is computed not only over the actual data, but including
 886 ; the SYNC mark (3 * $a1) and the 'ID/DATA - Address Mark' ($fe/$fb).
 887 ; As we don't read or encode these fields into our buffers, we have to
 888 ; preload the registers containing the CRC with the values they would have
 889 ; after stepping over these fields.
 890 ;
 891 ; How CRCs "really" work:
 892 ;
 893 ; First, you should regard a bitstring as a series of coefficients of
 894 ; polynomials. We calculate with these polynomials in modulo-2
 895 ; arithmetic, in which both add and subtract are done the same as
 896 ; exclusive-or. Now, we modify our data (a very long polynomial) in
 897 ; such a way that it becomes divisible by the CCITT-standard 16-bit
 898 ;                16   12   5
 899 ; polynomial:   x  + x  + x + 1, represented by $11021. The easiest
 900 ; way to do this would be to multiply (using proper arithmetic) our
 901 ; datablock with $11021. So we have:
 902 ;   data * $11021                =
 903 ;   data * ($10000 + $1021)      =
 904 ;   data * $10000 + data * $1021
 905 ; The left part of this is simple: Just add two 0 bytes. But then
 906 ; the right part (data $1021) remains difficult and even could have
 907 ; a carry into the left part. The solution is to use a modified
 908 ; multiplication, which has a result that is not correct, but with
 909 ; a difference of any multiple of $11021. We then only need to keep
 910 ; the 16 least significant bits of the result.
 911 ;
 912 ; The following algorithm does this for us:
 913 ;
 914 ;   unsigned char *data, c, crclo, crchi;
 915 ;   while (not done) {
 916 ;       c = *data++ + crchi;
 917 ;       crchi = (@ c) >> 8 + crclo;
 918 ;       crclo = @ c;
 919 ;   }
 920 ;
 921 ; Remember, + is done with EOR, the @ operator is in two tables (high
 922 ; and low byte separately), which is calculated as
 923 ;
 924 ;      $1021 * (c & $F0)
 925 ;  xor $1021 * (c & $0F)
 926 ;  xor $1021 * (c >> 4)         (* is regular multiplication)
 927 ;
 928 ;
 929 ; Anyway, the end result is the same as the remainder of the division of
 930 ; the data by $11021. I am afraid I need to study theory a bit more...
 931
 932
 933 my only works was to code this from manx to C....
 934
 935 */
 936
 937 static ushort dos_crc(void * data_a3, int data_d0, int data_d1, int data_d3)
 938 {
 939         static unsigned char CRCTable1[] = {
 940                 0x00,0x10,0x20,0x30,0x40,0x50,0x60,0x70,0x81,0x91,0xa1,0xb1,0xc1,0xd1,0xe1,0xf1,
 941                 0x12,0x02,0x32,0x22,0x52,0x42,0x72,0x62,0x93,0x83,0xb3,0xa3,0xd3,0xc3,0xf3,0xe3,
 942                 0x24,0x34,0x04,0x14,0x64,0x74,0x44,0x54,0xa5,0xb5,0x85,0x95,0xe5,0xf5,0xc5,0xd5,
 943                 0x36,0x26,0x16,0x06,0x76,0x66,0x56,0x46,0xb7,0xa7,0x97,0x87,0xf7,0xe7,0xd7,0xc7,
 944                 0x48,0x58,0x68,0x78,0x08,0x18,0x28,0x38,0xc9,0xd9,0xe9,0xf9,0x89,0x99,0xa9,0xb9,
 945                 0x5a,0x4a,0x7a,0x6a,0x1a,0x0a,0x3a,0x2a,0xdb,0xcb,0xfb,0xeb,0x9b,0x8b,0xbb,0xab,
 946                 0x6c,0x7c,0x4c,0x5c,0x2c,0x3c,0x0c,0x1c,0xed,0xfd,0xcd,0xdd,0xad,0xbd,0x8d,0x9d,
 947                 0x7e,0x6e,0x5e,0x4e,0x3e,0x2e,0x1e,0x0e,0xff,0xef,0xdf,0xcf,0xbf,0xaf,0x9f,0x8f,
 948                 0x91,0x81,0xb1,0xa1,0xd1,0xc1,0xf1,0xe1,0x10,0x00,0x30,0x20,0x50,0x40,0x70,0x60,
 949                 0x83,0x93,0xa3,0xb3,0xc3,0xd3,0xe3,0xf3,0x02,0x12,0x22,0x32,0x42,0x52,0x62,0x72,
 950                 0xb5,0xa5,0x95,0x85,0xf5,0xe5,0xd5,0xc5,0x34,0x24,0x14,0x04,0x74,0x64,0x54,0x44,
 951                 0xa7,0xb7,0x87,0x97,0xe7,0xf7,0xc7,0xd7,0x26,0x36,0x06,0x16,0x66,0x76,0x46,0x56,
 952                 0xd9,0xc9,0xf9,0xe9,0x99,0x89,0xb9,0xa9,0x58,0x48,0x78,0x68,0x18,0x08,0x38,0x28,
 953                 0xcb,0xdb,0xeb,0xfb,0x8b,0x9b,0xab,0xbb,0x4a,0x5a,0x6a,0x7a,0x0a,0x1a,0x2a,0x3a,
 954                 0xfd,0xed,0xdd,0xcd,0xbd,0xad,0x9d,0x8d,0x7c,0x6c,0x5c,0x4c,0x3c,0x2c,0x1c,0x0c,
 955                 0xef,0xff,0xcf,0xdf,0xaf,0xbf,0x8f,0x9f,0x6e,0x7e,0x4e,0x5e,0x2e,0x3e,0x0e,0x1e
 956         };
 957
 958         static unsigned char CRCTable2[] = {
 959                 0x00,0x21,0x42,0x63,0x84,0xa5,0xc6,0xe7,0x08,0x29,0x4a,0x6b,0x8c,0xad,0xce,0xef,
 960                 0x31,0x10,0x73,0x52,0xb5,0x94,0xf7,0xd6,0x39,0x18,0x7b,0x5a,0xbd,0x9c,0xff,0xde,
 961                 0x62,0x43,0x20,0x01,0xe6,0xc7,0xa4,0x85,0x6a,0x4b,0x28,0x09,0xee,0xcf,0xac,0x8d,
 962                 0x53,0x72,0x11,0x30,0xd7,0xf6,0x95,0xb4,0x5b,0x7a,0x19,0x38,0xdf,0xfe,0x9d,0xbc,
 963                 0xc4,0xe5,0x86,0xa7,0x40,0x61,0x02,0x23,0xcc,0xed,0x8e,0xaf,0x48,0x69,0x0a,0x2b,
 964                 0xf5,0xd4,0xb7,0x96,0x71,0x50,0x33,0x12,0xfd,0xdc,0xbf,0x9e,0x79,0x58,0x3b,0x1a,
 965                 0xa6,0x87,0xe4,0xc5,0x22,0x03,0x60,0x41,0xae,0x8f,0xec,0xcd,0x2a,0x0b,0x68,0x49,
 966                 0x97,0xb6,0xd5,0xf4,0x13,0x32,0x51,0x70,0x9f,0xbe,0xdd,0xfc,0x1b,0x3a,0x59,0x78,
 967                 0x88,0xa9,0xca,0xeb,0x0c,0x2d,0x4e,0x6f,0x80,0xa1,0xc2,0xe3,0x04,0x25,0x46,0x67,
 968                 0xb9,0x98,0xfb,0xda,0x3d,0x1c,0x7f,0x5e,0xb1,0x90,0xf3,0xd2,0x35,0x14,0x77,0x56,
 969                 0xea,0xcb,0xa8,0x89,0x6e,0x4f,0x2c,0x0d,0xe2,0xc3,0xa0,0x81,0x66,0x47,0x24,0x05,
 970                 0xdb,0xfa,0x99,0xb8,0x5f,0x7e,0x1d,0x3c,0xd3,0xf2,0x91,0xb0,0x57,0x76,0x15,0x34,
 971                 0x4c,0x6d,0x0e,0x2f,0xc8,0xe9,0x8a,0xab,0x44,0x65,0x06,0x27,0xc0,0xe1,0x82,0xa3,
 972                 0x7d,0x5c,0x3f,0x1e,0xf9,0xd8,0xbb,0x9a,0x75,0x54,0x37,0x16,0xf1,0xd0,0xb3,0x92,
 973                 0x2e,0x0f,0x6c,0x4d,0xaa,0x8b,0xe8,0xc9,0x26,0x07,0x64,0x45,0xa2,0x83,0xe0,0xc1,
 974                 0x1f,0x3e,0x5d,0x7c,0x9b,0xba,0xd9,0xf8,0x17,0x36,0x55,0x74,0x93,0xb2,0xd1,0xf0
 975         };
 976
 977 /* look at the asm-code - what looks in C a bit strange is almost as good as handmade */
 978         register int i;
 979         register unsigned char *CRCT1, *CRCT2, *data, c, crch, crcl;
 980
 981         CRCT1=CRCTable1;
 982         CRCT2=CRCTable2;
 983         data=data_a3;
 984         crcl=data_d1;
 985         crch=data_d0;
 986         for (i=data_d3; i>=0; i--) {
 987                 c = (*data++) ^ crch;
 988                 crch = CRCT1[c] ^ crcl;
 989                 crcl = CRCT2[c];
 990         }
 991         return (crch<<8)|crcl;
 992 }
 993
 994 static inline ushort dos_hdr_crc (struct dos_header *hdr)
 995 {
 996         return dos_crc(&(hdr->track), 0xb2, 0x30, 3); /* precomputed magic */
 997 }
 998
 999 static inline ushort dos_data_crc(unsigned char *data)
1000 {
1001         return dos_crc(data, 0xe2, 0x95 ,511); /* precomputed magic */
1002 }
1003
1004 static inline unsigned char dos_decode_byte(ushort word)
1005 {
1006         register ushort w2;
1007         register unsigned char byte;
1008         register unsigned char *dec = mfmdecode;
1009
1010         w2=word;
1011         w2>>=8;
1012         w2&=127;
1013         byte = dec[w2];
1014         byte <<= 4;
1015         w2 = word & 127;
1016         byte |= dec[w2];
1017         return byte;
1018 }
1019
1020 static unsigned long dos_decode(unsigned char *data, unsigned short *raw, int len)
1021 {
1022         int i;
1023
1024         for (i = 0; i < len; i++)
1025                 *data++=dos_decode_byte(*raw++);
1026         return ((ulong)raw);
1027 }
1028
1029 #ifdef DEBUG
1030 static void dbg(unsigned long ptr)
1031 {
1032         printk("raw data @%08lx: %08lx, %08lx ,%08lx, %08lx\n", ptr,
1033                ((ulong *)ptr)[0], ((ulong *)ptr)[1],
1034                ((ulong *)ptr)[2], ((ulong *)ptr)[3]);
1035 }
1036 #endif
1037
1038 static int dos_read(int drive)
1039 {
1040         unsigned long end;
1041         unsigned long raw;
1042         int scnt;
1043         unsigned short crc,data_crc[2];
1044         struct dos_header hdr;
1045
1046         drive&=3;
1047         raw = (long) raw_buf;
1048         end = raw + unit[drive].type->read_size;
1049
1050         for (scnt=0; scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
1051                 do { /* search for the right sync of each sec-hdr */
1052                         if (!(raw = scan_sync (raw, end))) {
1053                                 printk(KERN_INFO "dos_read: no hdr sync on "
1054                                        "track %d, unit %d for sector %d\n",
1055                                        unit[drive].track,drive,scnt);
1056                                 return MFM_NOSYNC;
1057                         }
1058 #ifdef DEBUG
1059                         dbg(raw);
1060 #endif
1061                 } while (*((ushort *)raw)!=0x5554); /* loop usually only once done */
1062                 raw+=2; /* skip over headermark */
1063                 raw = dos_decode((unsigned char *)&hdr,(ushort *) raw,8);
1064                 crc = dos_hdr_crc(&hdr);
1065
1066 #ifdef DEBUG
1067                 printk("(%3d,%d,%2d,%d) %x\n", hdr.track, hdr.side,
1068                        hdr.sec, hdr.len_desc, hdr.crc);
1069 #endif
1070
1071                 if (crc != hdr.crc) {
1072                         printk(KERN_INFO "dos_read: MFM_HEADER %04x,%04x\n",
1073                                hdr.crc, crc);
1074                         return MFM_HEADER;
1075                 }
1076                 if (hdr.track != unit[drive].track/unit[drive].type->heads) {
1077                         printk(KERN_INFO "dos_read: MFM_TRACK %d, %d\n",
1078                                hdr.track,
1079                                unit[drive].track/unit[drive].type->heads);
1080                         return MFM_TRACK;
1081                 }
1082
1083                 if (hdr.side != unit[drive].track%unit[drive].type->heads) {
1084                         printk(KERN_INFO "dos_read: MFM_SIDE %d, %d\n",
1085                                hdr.side,
1086                                unit[drive].track%unit[drive].type->heads);
1087                         return MFM_TRACK;
1088                 }
1089
1090                 if (hdr.len_desc != 2) {
1091                         printk(KERN_INFO "dos_read: unknown sector len "
1092                                "descriptor %d\n", hdr.len_desc);
1093                         return MFM_DATA;
1094                 }
1095 #ifdef DEBUG
1096                 printk("hdr accepted\n");
1097 #endif
1098                 if (!(raw = scan_sync (raw, end))) {
1099                         printk(KERN_INFO "dos_read: no data sync on track "
1100                                "%d, unit %d for sector%d, disk sector %d\n",
1101                                unit[drive].track, drive, scnt, hdr.sec);
1102                         return MFM_NOSYNC;
1103                 }
1104 #ifdef DEBUG
1105                 dbg(raw);
1106 #endif
1107
1108                 if (*((ushort *)raw)!=0x5545) {
1109                         printk(KERN_INFO "dos_read: no data mark after "
1110                                "sync (%d,%d,%d,%d) sc=%d\n",
1111                                hdr.track,hdr.side,hdr.sec,hdr.len_desc,scnt);
1112                         return MFM_NOSYNC;
1113                 }
1114
1115                 raw+=2;  /* skip data mark (included in checksum) */
1116                 raw = dos_decode((unsigned char *)(unit[drive].trackbuf + (hdr.sec - 1) * 512), (ushort *) raw, 512);
1117                 raw = dos_decode((unsigned char  *)data_crc,(ushort *) raw,4);
1118                 crc = dos_data_crc(unit[drive].trackbuf + (hdr.sec - 1) * 512);
1119
1120                 if (crc != data_crc[0]) {
1121                         printk(KERN_INFO "dos_read: MFM_DATA (%d,%d,%d,%d) "
1122                                "sc=%d, %x %x\n", hdr.track, hdr.side,
1123                                hdr.sec, hdr.len_desc, scnt,data_crc[0], crc);
1124                         printk(KERN_INFO "data=(%lx,%lx,%lx,%lx,...)\n",
1125                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[0],
1126                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[1],
1127                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[2],
1128                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[3]);
1129                         return MFM_DATA;
1130                 }
1131         }
1132         return 0;
1133 }
1134
1135 static inline ushort dos_encode_byte(unsigned char byte)
1136 {
1137         register unsigned char *enc, b2, b1;
1138         register ushort word;
1139
1140         enc=mfmencode;
1141         b1=byte;
1142         b2=b1>>4;
1143         b1&=15;
1144         word=enc[b2] <<8 | enc [b1];
1145         return (word|((word&(256|64)) ? 0: 128));
1146 }
1147
1148 static void dos_encode_block(ushort *dest, unsigned char *src, int len)
1149 {
1150         int i;
1151
1152         for (i = 0; i < len; i++) {
1153                 *dest=dos_encode_byte(*src++);
1154                 *dest|=((dest[-1]&1)||(*dest&0x4000))? 0: 0x8000;
1155                 dest++;
1156         }
1157 }
1158
1159 static unsigned long *ms_putsec(int drive, unsigned long *raw, int cnt)
1160 {
1161         static struct dos_header hdr={0,0,0,2,0,
1162           {78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78}};
1163         int i;
1164         static ushort crc[2]={0,0x4e4e};
1165
1166         drive&=3;
1167 /* id gap 1 */
1168 /* the MFM word before is always 9254 */
1169         for(i=0;i<6;i++)
1170                 *raw++=0xaaaaaaaa;
1171 /* 3 sync + 1 headermark */
1172         *raw++=0x44894489;
1173         *raw++=0x44895554;
1174
1175 /* fill in the variable parts of the header */
1176         hdr.track=unit[drive].track/unit[drive].type->heads;
1177         hdr.side=unit[drive].track%unit[drive].type->heads;
1178         hdr.sec=cnt+1;
1179         hdr.crc=dos_hdr_crc(&hdr);
1180
1181 /* header (without "magic") and id gap 2*/
1182         dos_encode_block((ushort *)raw,(unsigned char *) &hdr.track,28);
1183         raw+=14;
1184
1185 /*id gap 3 */
1186         for(i=0;i<6;i++)
1187                 *raw++=0xaaaaaaaa;
1188
1189 /* 3 syncs and 1 datamark */
1190         *raw++=0x44894489;
1191         *raw++=0x44895545;
1192
1193 /* data */
1194         dos_encode_block((ushort *)raw,
1195                          (unsigned char *)unit[drive].trackbuf+cnt*512,512);
1196         raw+=256;
1197
1198 /*data crc + jd's special gap (long words :-/) */
1199         crc[0]=dos_data_crc(unit[drive].trackbuf+cnt*512);
1200         dos_encode_block((ushort *) raw,(unsigned char *)crc,4);
1201         raw+=2;
1202
1203 /* data gap */
1204         for(i=0;i<38;i++)
1205                 *raw++=0x92549254;
1206
1207         return raw; /* wrote 652 MFM words */
1208 }
1209
1210 static void dos_write(int disk)
1211 {
1212         int cnt;
1213         unsigned long raw = (unsigned long) raw_buf;
1214         unsigned long *ptr=(unsigned long *)raw;
1215
1216         disk&=3;
1217 /* really gap4 + indexgap , but we write it first and round it up */
1218         for (cnt=0;cnt<425;cnt++)
1219                 *ptr++=0x92549254;
1220
1221 /* the following is just guessed */
1222         if (unit[disk].type->sect_mult==2)  /* check for HD-Disks */
1223                 for(cnt=0;cnt<473;cnt++)
1224                         *ptr++=0x92549254;
1225
1226 /* now the index marks...*/
1227         for (cnt=0;cnt<20;cnt++)
1228                 *ptr++=0x92549254;
1229         for (cnt=0;cnt<6;cnt++)
1230                 *ptr++=0xaaaaaaaa;
1231         *ptr++=0x52245224;
1232         *ptr++=0x52245552;
1233         for (cnt=0;cnt<20;cnt++)
1234                 *ptr++=0x92549254;
1235
1236 /* sectors */
1237         for(cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
1238                 ptr=ms_putsec(disk,ptr,cnt);
1239
1240         *(ushort *)ptr = 0xaaa8; /* MFM word before is always 0x9254 */
1241 }
1242
1243 /*
1244  * Here comes the high level stuff (i.e. the filesystem interface)
1245  * and helper functions.
1246  * Normally this should be the only part that has to be adapted to
1247  * different kernel versions.
1248  */
1249
1250 /* FIXME: this assumes the drive is still spinning -
1251  * which is only true if we complete writing a track within three seconds
1252  */
1253 static void flush_track_callback(unsigned long nr)
1254 {
1255         nr&=3;
1256         writefromint = 1;
1257         if (!try_fdc(nr)) {
1258                 /* we might block in an interrupt, so try again later */
1259                 flush_track_timer[nr].expires = jiffies + 1;
1260                 add_timer(flush_track_timer + nr);
1261                 return;
1262         }
1263         get_fdc(nr);
1264         (*unit[nr].dtype->write_fkt)(nr);
1265         if (!raw_write(nr)) {
1266                 printk (KERN_NOTICE "floppy disk write protected\n");
1267                 writefromint = 0;
1268                 writepending = 0;
1269         }
1270         rel_fdc();
1271 }
1272
1273 static int non_int_flush_track (unsigned long nr)
1274 {
1275         unsigned long flags;
1276
1277         nr&=3;
1278         writefromint = 0;
1279         del_timer(&post_write_timer);
1280         get_fdc(nr);
1281         if (!fd_motor_on(nr)) {
1282                 writepending = 0;
1283                 rel_fdc();
1284                 return 0;
1285         }
1286         local_irq_save(flags);
1287         if (writepending != 2) {
1288                 local_irq_restore(flags);
1289                 (*unit[nr].dtype->write_fkt)(nr);
1290                 if (!raw_write(nr)) {
1291                         printk (KERN_NOTICE "floppy disk write protected "
1292                                 "in write!\n");
1293                         writepending = 0;
1294                         return 0;
1295                 }
1296                 while (block_flag == 2)
1297                         sleep_on (&wait_fd_block);
1298         }
1299         else {
1300                 local_irq_restore(flags);
1301                 ms_delay(2); /* 2 ms post_write delay */
1302                 post_write(nr);
1303         }
1304         rel_fdc();
1305         return 1;
1306 }
1307
1308 static int get_track(int drive, int track)
1309 {
1310         int error, errcnt;
1311
1312         drive&=3;
1313         if (unit[drive].track == track)
1314                 return 0;
1315         get_fdc(drive);
1316         if (!fd_motor_on(drive)) {
1317                 rel_fdc();
1318                 return -1;
1319         }
1320
1321         if (unit[drive].dirty == 1) {
1322                 del_timer (flush_track_timer + drive);
1323                 non_int_flush_track (drive);
1324         }
1325         errcnt = 0;
1326         while (errcnt < MAX_ERRORS) {
1327                 if (!fd_seek(drive, track))
1328                         return -1;
1329                 raw_read(drive);
1330                 error = (*unit[drive].dtype->read_fkt)(drive);
1331                 if (error == 0) {
1332                         rel_fdc();
1333                         return 0;
1334                 }
1335                 /* Read Error Handling: recalibrate and try again */
1336                 unit[drive].track = -1;
1337                 errcnt++;
1338         }
1339         rel_fdc();
1340         return -1;
1341 }
1342
1343 static void redo_fd_request(void)
1344 {
1345         unsigned int cnt, block, track, sector;
1346         int drive;
1347         struct amiga_floppy_struct *floppy;
1348         char *data;
1349         unsigned long flags;
1350
1351  repeat:
1352         if (!CURRENT) {
1353                 /* Nothing left to do */
1354                 return;
1355         }
1356
1357         floppy = CURRENT->rq_disk->private_data;
1358         drive = floppy - unit;
1359
1360         /* Here someone could investigate to be more efficient */
1361         for (cnt = 0; cnt < CURRENT->current_nr_sectors; cnt++) {
1362 #ifdef DEBUG
1363                 printk("fd: sector %ld + %d requested for %s\n",
1364                        CURRENT->sector,cnt,
1365                        (CURRENT->cmd==READ)?"read":"write");
1366 #endif
1367                 block = CURRENT->sector + cnt;
1368                 if ((int)block > floppy->blocks) {
1369                         end_request(CURRENT, 0);
1370                         goto repeat;
1371                 }
1372
1373                 track = block / (floppy->dtype->sects * floppy->type->sect_mult);
1374                 sector = block % (floppy->dtype->sects * floppy->type->sect_mult);
1375                 data = CURRENT->buffer + 512 * cnt;
1376 #ifdef DEBUG
1377                 printk("access to track %d, sector %d, with buffer at "
1378                        "0x%08lx\n", track, sector, data);
1379 #endif
1380
1381                 if ((rq_data_dir(CURRENT) != READ) && (rq_data_dir(CURRENT) != WRITE)) {
1382                         printk(KERN_WARNING "do_fd_request: unknown command\n");
1383                         end_request(CURRENT, 0);
1384                         goto repeat;
1385                 }
1386                 if (get_track(drive, track) == -1) {
1387                         end_request(CURRENT, 0);
1388                         goto repeat;
1389                 }
1390
1391                 switch (rq_data_dir(CURRENT)) {
1392                 case READ:
1393                         memcpy(data, floppy->trackbuf + sector * 512, 512);
1394                         break;
1395
1396                 case WRITE:
1397                         memcpy(floppy->trackbuf + sector * 512, data, 512);
1398
1399                         /* keep the drive spinning while writes are scheduled */
1400                         if (!fd_motor_on(drive)) {
1401                                 end_request(CURRENT, 0);
1402                                 goto repeat;
1403                         }
1404                         /*
1405                          * setup a callback to write the track buffer
1406                          * after a short (1 tick) delay.
1407                          */
1408                         local_irq_save(flags);
1409
1410                         floppy->dirty = 1;
1411                         /* reset the timer */
1412                         mod_timer (flush_track_timer + drive, jiffies + 1);
1413                         local_irq_restore(flags);
1414                         break;
1415                 }
1416         }
1417         CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
1418         CURRENT->sector += CURRENT->current_nr_sectors;
1419
1420         end_request(CURRENT, 1);
1421         goto repeat;
1422 }
1423
1424 static void do_fd_request(request_queue_t * q)
1425 {
1426         redo_fd_request();
1427 }
1428
1429 static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1430 {
1431         int drive = MINOR(bdev->bd_dev) & 3;
1432
1433         geo->heads = unit[drive].type->heads;
1434         geo->sectors = unit[drive].dtype->sects * unit[drive].type->sect_mult;
1435         geo->cylinders = unit[drive].type->tracks;
1436         return 0;
1437 }
1438
1439 static int fd_ioctl(struct inode *inode, struct file *filp,
1440                     unsigned int cmd, unsigned long param)
1441 {
1442         int drive = iminor(inode) & 3;
1443         static struct floppy_struct getprm;
1444         void __user *argp = (void __user *)param;
1445
1446         switch(cmd){
1447         case FDFMTBEG:
1448                 get_fdc(drive);
1449                 if (fd_ref[drive] > 1) {
1450                         rel_fdc();
1451                         return -EBUSY;
1452                 }
1453                 fsync_bdev(inode->i_bdev);
1454                 if (fd_motor_on(drive) == 0) {
1455                         rel_fdc();
1456                         return -ENODEV;
1457                 }
1458                 if (fd_calibrate(drive) == 0) {
1459                         rel_fdc();
1460                         return -ENXIO;
1461                 }
1462                 floppy_off(drive);
1463                 rel_fdc();
1464                 break;
1465         case FDFMTTRK:
1466                 if (param < unit[drive].type->tracks * unit[drive].type->heads)
1467                 {
1468                         get_fdc(drive);
1469                         if (fd_seek(drive,param) != 0){
1470                                 memset(unit[drive].trackbuf, FD_FILL_BYTE,
1471                                        unit[drive].dtype->sects * unit[drive].type->sect_mult * 512);
1472                                 non_int_flush_track(drive);
1473                         }
1474                         floppy_off(drive);
1475                         rel_fdc();
1476                 }
1477                 else
1478                         return -EINVAL;
1479                 break;
1480         case FDFMTEND:
1481                 floppy_off(drive);
1482                 invalidate_bdev(inode->i_bdev, 0);
1483                 break;
1484         case FDGETPRM:
1485                 memset((void *)&getprm, 0, sizeof (getprm));
1486                 getprm.track=unit[drive].type->tracks;
1487                 getprm.head=unit[drive].type->heads;
1488                 getprm.sect=unit[drive].dtype->sects * unit[drive].type->sect_mult;
1489                 getprm.size=unit[drive].blocks;
1490                 if (copy_to_user(argp, &getprm, sizeof(struct floppy_struct)))
1491                         return -EFAULT;
1492                 break;
1493         case FDSETPRM:
1494         case FDDEFPRM:
1495                 return -EINVAL;
1496         case FDFLUSH: /* unconditionally, even if not needed */
1497                 del_timer (flush_track_timer + drive);
1498                 non_int_flush_track(drive);
1499                 break;
1500 #ifdef RAW_IOCTL
1501         case IOCTL_RAW_TRACK:
1502                 if (copy_to_user(argp, raw_buf, unit[drive].type->read_size))
1503                         return -EFAULT;
1504                 else
1505                         return unit[drive].type->read_size;
1506 #endif
1507         default:
1508                 printk(KERN_DEBUG "fd_ioctl: unknown cmd %d for drive %d.",
1509                        cmd, drive);
1510                 return -ENOSYS;
1511         }
1512         return 0;
1513 }
1514
1515 static void fd_probe(int dev)
1516 {
1517         unsigned long code;
1518         int type;
1519         int drive;
1520
1521         drive = dev & 3;
1522         code = fd_get_drive_id(drive);
1523
1524         /* get drive type */
1525         for (type = 0; type < num_dr_types; type++)
1526                 if (drive_types[type].code == code)
1527                         break;
1528
1529         if (type >= num_dr_types) {
1530                 printk(KERN_WARNING "fd_probe: unsupported drive type "
1531                        "%08lx found\n", code);
1532                 unit[drive].type = &drive_types[num_dr_types-1]; /* FD_NODRIVE */
1533                 return;
1534         }
1535
1536         unit[drive].type = drive_types + type;
1537         unit[drive].track = -1;
1538
1539         unit[drive].disk = -1;
1540         unit[drive].motor = 0;
1541         unit[drive].busy = 0;
1542         unit[drive].status = -1;
1543 }
1544
1545 /*
1546  * floppy_open check for aliasing (/dev/fd0 can be the same as
1547  * /dev/PS0 etc), and disallows simultaneous access to the same
1548  * drive with different device numbers.
1549  */
1550 static int floppy_open(struct inode *inode, struct file *filp)
1551 {
1552         int drive = iminor(inode) & 3;
1553         int system =  (iminor(inode) & 4) >> 2;
1554         int old_dev;
1555         unsigned long flags;
1556
1557         old_dev = fd_device[drive];
1558
1559         if (fd_ref[drive] && old_dev != system)
1560                 return -EBUSY;
1561
1562         if (filp && filp->f_mode & 3) {
1563                 check_disk_change(inode->i_bdev);
1564                 if (filp->f_mode & 2 ) {
1565                         int wrprot;
1566
1567                         get_fdc(drive);
1568                         fd_select (drive);
1569                         wrprot = !(ciaa.pra & DSKPROT);
1570                         fd_deselect (drive);
1571                         rel_fdc();
1572
1573                         if (wrprot)
1574                                 return -EROFS;
1575                 }
1576         }
1577
1578         local_irq_save(flags);
1579         fd_ref[drive]++;
1580         fd_device[drive] = system;
1581         local_irq_restore(flags);
1582
1583         unit[drive].dtype=&data_types[system];
1584         unit[drive].blocks=unit[drive].type->heads*unit[drive].type->tracks*
1585                 data_types[system].sects*unit[drive].type->sect_mult;
1586         set_capacity(unit[drive].gendisk, unit[drive].blocks);
1587
1588         printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
1589                unit[drive].type->name, data_types[system].name);
1590
1591         return 0;
1592 }
1593
1594 static int floppy_release(struct inode * inode, struct file * filp)
1595 {
1596         int drive = iminor(inode) & 3;
1597
1598         if (unit[drive].dirty == 1) {
1599                 del_timer (flush_track_timer + drive);
1600                 non_int_flush_track (drive);
1601         }
1602
1603         if (!fd_ref[drive]--) {
1604                 printk(KERN_CRIT "floppy_release with fd_ref == 0");
1605                 fd_ref[drive] = 0;
1606         }
1607 #ifdef MODULE
1608 /* the mod_use counter is handled this way */
1609         floppy_off (drive | 0x40000000);
1610 #endif
1611         return 0;
1612 }
1613
1614 /*
1615  * floppy-change is never called from an interrupt, so we can relax a bit
1616  * here, sleep etc. Note that floppy-on tries to set current_DOR to point
1617  * to the desired drive, but it will probably not survive the sleep if
1618  * several floppies are used at the same time: thus the loop.
1619  */
1620 static int amiga_floppy_change(struct gendisk *disk)
1621 {
1622         struct amiga_floppy_struct *p = disk->private_data;
1623         int drive = p - unit;
1624         int changed;
1625         static int first_time = 1;
1626
1627         if (first_time)
1628                 changed = first_time--;
1629         else {
1630                 get_fdc(drive);
1631                 fd_select (drive);
1632                 changed = !(ciaa.pra & DSKCHANGE);
1633                 fd_deselect (drive);
1634                 rel_fdc();
1635         }
1636
1637         if (changed) {
1638                 fd_probe(drive);
1639                 p->track = -1;
1640                 p->dirty = 0;
1641                 writepending = 0; /* if this was true before, too bad! */
1642                 writefromint = 0;
1643                 return 1;
1644         }
1645         return 0;
1646 }
1647
1648 static struct block_device_operations floppy_fops = {
1649         .owner          = THIS_MODULE,
1650         .open           = floppy_open,
1651         .release        = floppy_release,
1652         .ioctl          = fd_ioctl,
1653         .getgeo         = fd_getgeo,
1654         .media_changed  = amiga_floppy_change,
1655 };
1656
1657 static int __init fd_probe_drives(void)
1658 {
1659         int drive,drives,nomem;
1660
1661         printk(KERN_INFO "FD: probing units\n" KERN_INFO "found ");
1662         drives=0;
1663         nomem=0;
1664         for(drive=0;drive<FD_MAX_UNITS;drive++) {
1665                 struct gendisk *disk;
1666                 fd_probe(drive);
1667                 if (unit[drive].type->code == FD_NODRIVE)
1668                         continue;
1669                 disk = alloc_disk(1);
1670                 if (!disk) {
1671                         unit[drive].type->code = FD_NODRIVE;
1672                         continue;
1673                 }
1674                 unit[drive].gendisk = disk;
1675                 drives++;
1676                 if ((unit[drive].trackbuf = kmalloc(FLOPPY_MAX_SECTORS * 512, GFP_KERNEL)) == NULL) {
1677                         printk("no mem for ");
1678                         unit[drive].type = &drive_types[num_dr_types - 1]; /* FD_NODRIVE */
1679                         drives--;
1680                         nomem = 1;
1681                 }
1682                 printk("fd%d ",drive);
1683                 disk->major = FLOPPY_MAJOR;
1684                 disk->first_minor = drive;
1685                 disk->fops = &floppy_fops;
1686                 sprintf(disk->disk_name, "fd%d", drive);
1687                 disk->private_data = &unit[drive];
1688                 disk->queue = floppy_queue;
1689                 set_capacity(disk, 880*2);
1690                 add_disk(disk);
1691         }
1692         if ((drives > 0) || (nomem == 0)) {
1693                 if (drives == 0)
1694                         printk("no drives");
1695                 printk("\n");
1696                 return drives;
1697         }
1698         printk("\n");
1699         return -ENOMEM;
1700 }
1701
1702 static struct kobject *floppy_find(dev_t dev, int *part, void *data)
1703 {
1704         int drive = *part & 3;
1705         if (unit[drive].type->code == FD_NODRIVE)
1706                 return NULL;
1707         *part = 0;
1708         return get_disk(unit[drive].gendisk);
1709 }
1710
1711 int __init amiga_floppy_init(void)
1712 {
1713         int i, ret;
1714
1715         if (!AMIGAHW_PRESENT(AMI_FLOPPY))
1716                 return -ENXIO;
1717
1718         if (register_blkdev(FLOPPY_MAJOR,"fd"))
1719                 return -EBUSY;
1720
1721         /*
1722          *  We request DSKPTR, DSKLEN and DSKDATA only, because the other
1723          *  floppy registers are too spreaded over the custom register space
1724          */
1725         ret = -EBUSY;
1726         if (!request_mem_region(CUSTOM_PHYSADDR+0x20, 8, "amiflop [Paula]")) {
1727                 printk("fd: cannot get floppy registers\n");
1728                 goto out_blkdev;
1729         }
1730
1731         ret = -ENOMEM;
1732         if ((raw_buf = (char *)amiga_chip_alloc (RAW_BUF_SIZE, "Floppy")) ==
1733             NULL) {
1734                 printk("fd: cannot get chip mem buffer\n");
1735                 goto out_memregion;
1736         }
1737
1738         ret = -EBUSY;
1739         if (request_irq(IRQ_AMIGA_DSKBLK, fd_block_done, 0, "floppy_dma", NULL)) {
1740                 printk("fd: cannot get irq for dma\n");
1741                 goto out_irq;
1742         }
1743
1744         if (request_irq(IRQ_AMIGA_CIAA_TB, ms_isr, 0, "floppy_timer", NULL)) {
1745                 printk("fd: cannot get irq for timer\n");
1746                 goto out_irq2;
1747         }
1748
1749         ret = -ENOMEM;
1750         floppy_queue = blk_init_queue(do_fd_request, &amiflop_lock);
1751         if (!floppy_queue)
1752                 goto out_queue;
1753
1754         ret = -ENXIO;
1755         if (fd_probe_drives() < 1) /* No usable drives */
1756                 goto out_probe;
1757
1758         blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
1759                                 floppy_find, NULL, NULL);
1760
1761         /* initialize variables */
1762         init_timer(&motor_on_timer);
1763         motor_on_timer.expires = 0;
1764         motor_on_timer.data = 0;
1765         motor_on_timer.function = motor_on_callback;
1766         for (i = 0; i < FD_MAX_UNITS; i++) {
1767                 init_timer(&motor_off_timer[i]);
1768                 motor_off_timer[i].expires = 0;
1769                 motor_off_timer[i].data = i|0x80000000;
1770                 motor_off_timer[i].function = fd_motor_off;
1771                 init_timer(&flush_track_timer[i]);
1772                 flush_track_timer[i].expires = 0;
1773                 flush_track_timer[i].data = i;
1774                 flush_track_timer[i].function = flush_track_callback;
1775
1776                 unit[i].track = -1;
1777         }
1778
1779         init_timer(&post_write_timer);
1780         post_write_timer.expires = 0;
1781         post_write_timer.data = 0;
1782         post_write_timer.function = post_write;
1783
1784         for (i = 0; i < 128; i++)
1785                 mfmdecode[i]=255;
1786         for (i = 0; i < 16; i++)
1787                 mfmdecode[mfmencode[i]]=i;
1788
1789         /* make sure that disk DMA is enabled */
1790         custom.dmacon = DMAF_SETCLR | DMAF_DISK;
1791
1792         /* init ms timer */
1793         ciaa.crb = 8; /* one-shot, stop */
1794         return 0;
1795
1796 out_probe:
1797         blk_cleanup_queue(floppy_queue);
1798 out_queue:
1799         free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1800 out_irq2:
1801         free_irq(IRQ_AMIGA_DSKBLK, NULL);
1802 out_irq:
1803         amiga_chip_free(raw_buf);
1804 out_memregion:
1805         release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1806 out_blkdev:
1807         unregister_blkdev(FLOPPY_MAJOR,"fd");
1808         return ret;
1809 }
1810
1811 #ifdef MODULE
1812
1813 int init_module(void)
1814 {
1815         if (!MACH_IS_AMIGA)
1816                 return -ENXIO;
1817         return amiga_floppy_init();
1818 }
1819
1820 #if 0 /* not safe to unload */
1821 void cleanup_module(void)
1822 {
1823         int i;
1824
1825         for( i = 0; i < FD_MAX_UNITS; i++) {
1826                 if (unit[i].type->code != FD_NODRIVE) {
1827                         del_gendisk(unit[i].gendisk);
1828                         put_disk(unit[i].gendisk);
1829                         kfree(unit[i].trackbuf);
1830                 }
1831         }
1832         blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
1833         free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1834         free_irq(IRQ_AMIGA_DSKBLK, NULL);
1835         custom.dmacon = DMAF_DISK; /* disable DMA */
1836         amiga_chip_free(raw_buf);
1837         blk_cleanup_queue(floppy_queue);
1838         release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1839         unregister_blkdev(FLOPPY_MAJOR, "fd");
1840 }
1841 #endif
1842
1843 #else
1844 static int __init amiga_floppy_setup (char *str)
1845 {
1846         int n;
1847         if (!MACH_IS_AMIGA)
1848                 return 0;
1849         if (!get_option(&str, &n))
1850                 return 0;
1851         printk (KERN_INFO "amiflop: Setting default df0 to %x\n", n);
1852         fd_def_df0 = n;
1853         return 1;
1854 }
1855
1856 __setup("floppy=", amiga_floppy_setup);
1857 #endif