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 #include <linux/slab.h>
  58
  59 #include <linux/fd.h>
  60 #include <linux/hdreg.h>
  61 #include <linux/delay.h>
  62 #include <linux/init.h>
  63 #include <linux/amifdreg.h>
  64 #include <linux/amifd.h>
  65 #include <linux/buffer_head.h>
  66 #include <linux/blkdev.h>
  67 #include <linux/elevator.h>
  68 #include <linux/interrupt.h>
  69
  70 #include <asm/setup.h>
  71 #include <asm/uaccess.h>
  72 #include <asm/amigahw.h>
  73 #include <asm/amigaints.h>
  74 #include <asm/irq.h>
  75
  76 #undef DEBUG /* print _LOTS_ of infos */
  77
  78 #define RAW_IOCTL
  79 #ifdef RAW_IOCTL
  80 #define IOCTL_RAW_TRACK 0x5254524B  /* 'RTRK' */
  81 #endif
  82
  83 /*
  84  *  Defines
  85  */
  86
  87 /*
  88  *  Error codes
  89  */
  90 #define FD_OK           0       /* operation succeeded */
  91 #define FD_ERROR        -1      /* general error (seek, read, write, etc) */
  92 #define FD_NOUNIT       1       /* unit does not exist */
  93 #define FD_UNITBUSY     2       /* unit already active */
  94 #define FD_NOTACTIVE    3       /* unit is not active */
  95 #define FD_NOTREADY     4       /* unit is not ready (motor not on/no disk) */
  96
  97 #define MFM_NOSYNC      1
  98 #define MFM_HEADER      2
  99 #define MFM_DATA        3
 100 #define MFM_TRACK       4
 101
 102 /*
 103  *  Floppy ID values
 104  */
 105 #define FD_NODRIVE      0x00000000  /* response when no unit is present */
 106 #define FD_DD_3         0xffffffff  /* double-density 3.5" (880K) drive */
 107 #define FD_HD_3         0x55555555  /* high-density 3.5" (1760K) drive */
 108 #define FD_DD_5         0xaaaaaaaa  /* double-density 5.25" (440K) drive */
 109
 110 static unsigned long int fd_def_df0 = FD_DD_3;     /* default for df0 if it doesn't identify */
 111
 112 module_param(fd_def_df0, ulong, 0);
 113 MODULE_LICENSE("GPL");
 114
 115 static struct request_queue *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_COMPLETION(motor_on_completion);
 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 DECLARE_COMPLETION(ms_wait_completion);
 187 #define MS_TICKS ((amiga_eclock+50)/1000)
 188
 189 /*
 190  * Note that MAX_ERRORS=X doesn't imply that we retry every bad read
 191  * max X times - some types of errors increase the errorcount by 2 or
 192  * even 3, so we might actually retry only X/2 times before giving up.
 193  */
 194 #define MAX_ERRORS 12
 195
 196 #define custom amiga_custom
 197
 198 /* Prevent "aliased" accesses. */
 199 static int fd_ref[4] = { 0,0,0,0 };
 200 static int fd_device[4] = { 0, 0, 0, 0 };
 201
 202 /*
 203  * Here come the actual hardware access and helper functions.
 204  * They are not reentrant and single threaded because all drives
 205  * share the same hardware and the same trackbuffer.
 206  */
 207
 208 /* Milliseconds timer */
 209
 210 static irqreturn_t ms_isr(int irq, void *dummy)
 211 {
 212         complete(&ms_wait_completion);
 213         return IRQ_HANDLED;
 214 }
 215
 216 /* all waits are queued up
 217    A more generic routine would do a schedule a la timer.device */
 218 static void ms_delay(int ms)
 219 {
 220         int ticks;
 221         static DEFINE_MUTEX(mutex);
 222
 223         if (ms > 0) {
 224                 mutex_lock(&mutex);
 225                 ticks = MS_TICKS*ms-1;
 226                 ciaa.tblo=ticks%256;
 227                 ciaa.tbhi=ticks/256;
 228                 ciaa.crb=0x19; /*count eclock, force load, one-shoot, start */
 229                 wait_for_completion(&ms_wait_completion);
 230                 mutex_unlock(&mutex);
 231         }
 232 }
 233
 234 /* Hardware semaphore */
 235
 236 /* returns true when we would get the semaphore */
 237 static inline int try_fdc(int drive)
 238 {
 239         drive &= 3;
 240         return ((fdc_busy < 0) || (fdc_busy == drive));
 241 }
 242
 243 static void get_fdc(int drive)
 244 {
 245         unsigned long flags;
 246
 247         drive &= 3;
 248 #ifdef DEBUG
 249         printk("get_fdc: drive %d  fdc_busy %d  fdc_nested %d\n",drive,fdc_busy,fdc_nested);
 250 #endif
 251         local_irq_save(flags);
 252         wait_event(fdc_wait, try_fdc(drive));
 253         fdc_busy = drive;
 254         fdc_nested++;
 255         local_irq_restore(flags);
 256 }
 257
 258 static inline void rel_fdc(void)
 259 {
 260 #ifdef DEBUG
 261         if (fdc_nested == 0)
 262                 printk("fd: unmatched rel_fdc\n");
 263         printk("rel_fdc: fdc_busy %d fdc_nested %d\n",fdc_busy,fdc_nested);
 264 #endif
 265         fdc_nested--;
 266         if (fdc_nested == 0) {
 267                 fdc_busy = -1;
 268                 wake_up(&fdc_wait);
 269         }
 270 }
 271
 272 static void fd_select (int drive)
 273 {
 274         unsigned char prb = ~0;
 275
 276         drive&=3;
 277 #ifdef DEBUG
 278         printk("selecting %d\n",drive);
 279 #endif
 280         if (drive == selected)
 281                 return;
 282         get_fdc(drive);
 283         selected = drive;
 284
 285         if (unit[drive].track % 2 != 0)
 286                 prb &= ~DSKSIDE;
 287         if (unit[drive].motor == 1)
 288                 prb &= ~DSKMOTOR;
 289         ciab.prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
 290         ciab.prb = prb;
 291         prb &= ~SELMASK(drive);
 292         ciab.prb = prb;
 293         rel_fdc();
 294 }
 295
 296 static void fd_deselect (int drive)
 297 {
 298         unsigned char prb;
 299         unsigned long flags;
 300
 301         drive&=3;
 302 #ifdef DEBUG
 303         printk("deselecting %d\n",drive);
 304 #endif
 305         if (drive != selected) {
 306                 printk(KERN_WARNING "Deselecting drive %d while %d was selected!\n",drive,selected);
 307                 return;
 308         }
 309
 310         get_fdc(drive);
 311         local_irq_save(flags);
 312
 313         selected = -1;
 314
 315         prb = ciab.prb;
 316         prb |= (SELMASK(0)|SELMASK(1)|SELMASK(2)|SELMASK(3));
 317         ciab.prb = prb;
 318
 319         local_irq_restore (flags);
 320         rel_fdc();
 321
 322 }
 323
 324 static void motor_on_callback(unsigned long nr)
 325 {
 326         if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
 327                 complete_all(&motor_on_completion);
 328         } else {
 329                 motor_on_timer.expires = jiffies + HZ/10;
 330                 add_timer(&motor_on_timer);
 331         }
 332 }
 333
 334 static int fd_motor_on(int nr)
 335 {
 336         nr &= 3;
 337
 338         del_timer(motor_off_timer + nr);
 339
 340         if (!unit[nr].motor) {
 341                 unit[nr].motor = 1;
 342                 fd_select(nr);
 343
 344                 INIT_COMPLETION(motor_on_completion);
 345                 motor_on_timer.data = nr;
 346                 mod_timer(&motor_on_timer, jiffies + HZ/2);
 347
 348                 on_attempts = 10;
 349                 wait_for_completion(&motor_on_completion);
 350                 fd_deselect(nr);
 351         }
 352
 353         if (on_attempts == 0) {
 354                 on_attempts = -1;
 355 #if 0
 356                 printk (KERN_ERR "motor_on failed, turning motor off\n");
 357                 fd_motor_off (nr);
 358                 return 0;
 359 #else
 360                 printk (KERN_WARNING "DSKRDY not set after 1.5 seconds - assuming drive is spinning notwithstanding\n");
 361 #endif
 362         }
 363
 364         return 1;
 365 }
 366
 367 static void fd_motor_off(unsigned long drive)
 368 {
 369         long calledfromint;
 370 #ifdef MODULE
 371         long decusecount;
 372
 373         decusecount = drive & 0x40000000;
 374 #endif
 375         calledfromint = drive & 0x80000000;
 376         drive&=3;
 377         if (calledfromint && !try_fdc(drive)) {
 378                 /* We would be blocked in an interrupt, so try again later */
 379                 motor_off_timer[drive].expires = jiffies + 1;
 380                 add_timer(motor_off_timer + drive);
 381                 return;
 382         }
 383         unit[drive].motor = 0;
 384         fd_select(drive);
 385         udelay (1);
 386         fd_deselect(drive);
 387 }
 388
 389 static void floppy_off (unsigned int nr)
 390 {
 391         int drive;
 392
 393         drive = nr & 3;
 394         /* called this way it is always from interrupt */
 395         motor_off_timer[drive].data = nr | 0x80000000;
 396         mod_timer(motor_off_timer + drive, jiffies + 3*HZ);
 397 }
 398
 399 static int fd_calibrate(int drive)
 400 {
 401         unsigned char prb;
 402         int n;
 403
 404         drive &= 3;
 405         get_fdc(drive);
 406         if (!fd_motor_on (drive))
 407                 return 0;
 408         fd_select (drive);
 409         prb = ciab.prb;
 410         prb |= DSKSIDE;
 411         prb &= ~DSKDIREC;
 412         ciab.prb = prb;
 413         for (n = unit[drive].type->tracks/2; n != 0; --n) {
 414                 if (ciaa.pra & DSKTRACK0)
 415                         break;
 416                 prb &= ~DSKSTEP;
 417                 ciab.prb = prb;
 418                 prb |= DSKSTEP;
 419                 udelay (2);
 420                 ciab.prb = prb;
 421                 ms_delay(unit[drive].type->step_delay);
 422         }
 423         ms_delay (unit[drive].type->settle_time);
 424         prb |= DSKDIREC;
 425         n = unit[drive].type->tracks + 20;
 426         for (;;) {
 427                 prb &= ~DSKSTEP;
 428                 ciab.prb = prb;
 429                 prb |= DSKSTEP;
 430                 udelay (2);
 431                 ciab.prb = prb;
 432                 ms_delay(unit[drive].type->step_delay + 1);
 433                 if ((ciaa.pra & DSKTRACK0) == 0)
 434                         break;
 435                 if (--n == 0) {
 436                         printk (KERN_ERR "fd%d: calibrate failed, turning motor off\n", drive);
 437                         fd_motor_off (drive);
 438                         unit[drive].track = -1;
 439                         rel_fdc();
 440                         return 0;
 441                 }
 442         }
 443         unit[drive].track = 0;
 444         ms_delay(unit[drive].type->settle_time);
 445
 446         rel_fdc();
 447         fd_deselect(drive);
 448         return 1;
 449 }
 450
 451 static int fd_seek(int drive, int track)
 452 {
 453         unsigned char prb;
 454         int cnt;
 455
 456 #ifdef DEBUG
 457         printk("seeking drive %d to track %d\n",drive,track);
 458 #endif
 459         drive &= 3;
 460         get_fdc(drive);
 461         if (unit[drive].track == track) {
 462                 rel_fdc();
 463                 return 1;
 464         }
 465         if (!fd_motor_on(drive)) {
 466                 rel_fdc();
 467                 return 0;
 468         }
 469         if (unit[drive].track < 0 && !fd_calibrate(drive)) {
 470                 rel_fdc();
 471                 return 0;
 472         }
 473
 474         fd_select (drive);
 475         cnt = unit[drive].track/2 - track/2;
 476         prb = ciab.prb;
 477         prb |= DSKSIDE | DSKDIREC;
 478         if (track % 2 != 0)
 479                 prb &= ~DSKSIDE;
 480         if (cnt < 0) {
 481                 cnt = - cnt;
 482                 prb &= ~DSKDIREC;
 483         }
 484         ciab.prb = prb;
 485         if (track % 2 != unit[drive].track % 2)
 486                 ms_delay (unit[drive].type->side_time);
 487         unit[drive].track = track;
 488         if (cnt == 0) {
 489                 rel_fdc();
 490                 fd_deselect(drive);
 491                 return 1;
 492         }
 493         do {
 494                 prb &= ~DSKSTEP;
 495                 ciab.prb = prb;
 496                 prb |= DSKSTEP;
 497                 udelay (1);
 498                 ciab.prb = prb;
 499                 ms_delay (unit[drive].type->step_delay);
 500         } while (--cnt != 0);
 501         ms_delay (unit[drive].type->settle_time);
 502
 503         rel_fdc();
 504         fd_deselect(drive);
 505         return 1;
 506 }
 507
 508 static unsigned long fd_get_drive_id(int drive)
 509 {
 510         int i;
 511         ulong id = 0;
 512
 513         drive&=3;
 514         get_fdc(drive);
 515         /* set up for ID */
 516         MOTOR_ON;
 517         udelay(2);
 518         SELECT(SELMASK(drive));
 519         udelay(2);
 520         DESELECT(SELMASK(drive));
 521         udelay(2);
 522         MOTOR_OFF;
 523         udelay(2);
 524         SELECT(SELMASK(drive));
 525         udelay(2);
 526         DESELECT(SELMASK(drive));
 527         udelay(2);
 528
 529         /* loop and read disk ID */
 530         for (i=0; i<32; i++) {
 531                 SELECT(SELMASK(drive));
 532                 udelay(2);
 533
 534                 /* read and store value of DSKRDY */
 535                 id <<= 1;
 536                 id |= (ciaa.pra & DSKRDY) ? 0 : 1;      /* cia regs are low-active! */
 537
 538                 DESELECT(SELMASK(drive));
 539         }
 540
 541         rel_fdc();
 542
 543         /*
 544          * RB: At least A500/A2000's df0: don't identify themselves.
 545          * As every (real) Amiga has at least a 3.5" DD drive as df0:
 546          * we default to that if df0: doesn't identify as a certain
 547          * type.
 548          */
 549         if(drive == 0 && id == FD_NODRIVE)
 550         {
 551                 id = fd_def_df0;
 552                 printk(KERN_NOTICE "fd: drive 0 didn't identify, setting default %08lx\n", (ulong)fd_def_df0);
 553         }
 554         /* return the ID value */
 555         return (id);
 556 }
 557
 558 static irqreturn_t fd_block_done(int irq, void *dummy)
 559 {
 560         if (block_flag)
 561                 custom.dsklen = 0x4000;
 562
 563         if (block_flag == 2) { /* writing */
 564                 writepending = 2;
 565                 post_write_timer.expires = jiffies + 1; /* at least 2 ms */
 566                 post_write_timer.data = selected;
 567                 add_timer(&post_write_timer);
 568         }
 569         else {                /* reading */
 570                 block_flag = 0;
 571                 wake_up (&wait_fd_block);
 572         }
 573         return IRQ_HANDLED;
 574 }
 575
 576 static void raw_read(int drive)
 577 {
 578         drive&=3;
 579         get_fdc(drive);
 580         wait_event(wait_fd_block, !block_flag);
 581         fd_select(drive);
 582         /* setup adkcon bits correctly */
 583         custom.adkcon = ADK_MSBSYNC;
 584         custom.adkcon = ADK_SETCLR|ADK_WORDSYNC|ADK_FAST;
 585
 586         custom.dsksync = MFM_SYNC;
 587
 588         custom.dsklen = 0;
 589         custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
 590         custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
 591         custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
 592
 593         block_flag = 1;
 594
 595         wait_event(wait_fd_block, !block_flag);
 596
 597         custom.dsklen = 0;
 598         fd_deselect(drive);
 599         rel_fdc();
 600 }
 601
 602 static int raw_write(int drive)
 603 {
 604         ushort adk;
 605
 606         drive&=3;
 607         get_fdc(drive); /* corresponds to rel_fdc() in post_write() */
 608         if ((ciaa.pra & DSKPROT) == 0) {
 609                 rel_fdc();
 610                 return 0;
 611         }
 612         wait_event(wait_fd_block, !block_flag);
 613         fd_select(drive);
 614         /* clear adkcon bits */
 615         custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
 616         /* set appropriate adkcon bits */
 617         adk = ADK_SETCLR|ADK_FAST;
 618         if ((ulong)unit[drive].track >= unit[drive].type->precomp2)
 619                 adk |= ADK_PRECOMP1;
 620         else if ((ulong)unit[drive].track >= unit[drive].type->precomp1)
 621                 adk |= ADK_PRECOMP0;
 622         custom.adkcon = adk;
 623
 624         custom.dsklen = DSKLEN_WRITE;
 625         custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
 626         custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
 627         custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
 628
 629         block_flag = 2;
 630         return 1;
 631 }
 632
 633 /*
 634  * to be called at least 2ms after the write has finished but before any
 635  * other access to the hardware.
 636  */
 637 static void post_write (unsigned long drive)
 638 {
 639 #ifdef DEBUG
 640         printk("post_write for drive %ld\n",drive);
 641 #endif
 642         drive &= 3;
 643         custom.dsklen = 0;
 644         block_flag = 0;
 645         writepending = 0;
 646         writefromint = 0;
 647         unit[drive].dirty = 0;
 648         wake_up(&wait_fd_block);
 649         fd_deselect(drive);
 650         rel_fdc(); /* corresponds to get_fdc() in raw_write */
 651 }
 652
 653
 654 /*
 655  * The following functions are to convert the block contents into raw data
 656  * written to disk and vice versa.
 657  * (Add other formats here ;-))
 658  */
 659
 660 static unsigned long scan_sync(unsigned long raw, unsigned long end)
 661 {
 662         ushort *ptr = (ushort *)raw, *endp = (ushort *)end;
 663
 664         while (ptr < endp && *ptr++ != 0x4489)
 665                 ;
 666         if (ptr < endp) {
 667                 while (*ptr == 0x4489 && ptr < endp)
 668                         ptr++;
 669                 return (ulong)ptr;
 670         }
 671         return 0;
 672 }
 673
 674 static inline unsigned long checksum(unsigned long *addr, int len)
 675 {
 676         unsigned long csum = 0;
 677
 678         len /= sizeof(*addr);
 679         while (len-- > 0)
 680                 csum ^= *addr++;
 681         csum = ((csum>>1) & 0x55555555)  ^  (csum & 0x55555555);
 682
 683         return csum;
 684 }
 685
 686 static unsigned long decode (unsigned long *data, unsigned long *raw,
 687                              int len)
 688 {
 689         ulong *odd, *even;
 690
 691         /* convert length from bytes to longwords */
 692         len >>= 2;
 693         odd = raw;
 694         even = odd + len;
 695
 696         /* prepare return pointer */
 697         raw += len * 2;
 698
 699         do {
 700                 *data++ = ((*odd++ & 0x55555555) << 1) | (*even++ & 0x55555555);
 701         } while (--len != 0);
 702
 703         return (ulong)raw;
 704 }
 705
 706 struct header {
 707         unsigned char magic;
 708         unsigned char track;
 709         unsigned char sect;
 710         unsigned char ord;
 711         unsigned char labels[16];
 712         unsigned long hdrchk;
 713         unsigned long datachk;
 714 };
 715
 716 static int amiga_read(int drive)
 717 {
 718         unsigned long raw;
 719         unsigned long end;
 720         int scnt;
 721         unsigned long csum;
 722         struct header hdr;
 723
 724         drive&=3;
 725         raw = (long) raw_buf;
 726         end = raw + unit[drive].type->read_size;
 727
 728         for (scnt = 0;scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
 729                 if (!(raw = scan_sync(raw, end))) {
 730                         printk (KERN_INFO "can't find sync for sector %d\n", scnt);
 731                         return MFM_NOSYNC;
 732                 }
 733
 734                 raw = decode ((ulong *)&hdr.magic, (ulong *)raw, 4);
 735                 raw = decode ((ulong *)&hdr.labels, (ulong *)raw, 16);
 736                 raw = decode ((ulong *)&hdr.hdrchk, (ulong *)raw, 4);
 737                 raw = decode ((ulong *)&hdr.datachk, (ulong *)raw, 4);
 738                 csum = checksum((ulong *)&hdr,
 739                                 (char *)&hdr.hdrchk-(char *)&hdr);
 740
 741 #ifdef DEBUG
 742                 printk ("(%x,%d,%d,%d) (%lx,%lx,%lx,%lx) %lx %lx\n",
 743                         hdr.magic, hdr.track, hdr.sect, hdr.ord,
 744                         *(ulong *)&hdr.labels[0], *(ulong *)&hdr.labels[4],
 745                         *(ulong *)&hdr.labels[8], *(ulong *)&hdr.labels[12],
 746                         hdr.hdrchk, hdr.datachk);
 747 #endif
 748
 749                 if (hdr.hdrchk != csum) {
 750                         printk(KERN_INFO "MFM_HEADER: %08lx,%08lx\n", hdr.hdrchk, csum);
 751                         return MFM_HEADER;
 752                 }
 753
 754                 /* verify track */
 755                 if (hdr.track != unit[drive].track) {
 756                         printk(KERN_INFO "MFM_TRACK: %d, %d\n", hdr.track, unit[drive].track);
 757                         return MFM_TRACK;
 758                 }
 759
 760                 raw = decode ((ulong *)(unit[drive].trackbuf + hdr.sect*512),
 761                               (ulong *)raw, 512);
 762                 csum = checksum((ulong *)(unit[drive].trackbuf + hdr.sect*512), 512);
 763
 764                 if (hdr.datachk != csum) {
 765                         printk(KERN_INFO "MFM_DATA: (%x:%d:%d:%d) sc=%d %lx, %lx\n",
 766                                hdr.magic, hdr.track, hdr.sect, hdr.ord, scnt,
 767                                hdr.datachk, csum);
 768                         printk (KERN_INFO "data=(%lx,%lx,%lx,%lx)\n",
 769                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[0],
 770                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[1],
 771                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[2],
 772                                 ((ulong *)(unit[drive].trackbuf+hdr.sect*512))[3]);
 773                         return MFM_DATA;
 774                 }
 775         }
 776
 777         return 0;
 778 }
 779
 780 static void encode(unsigned long data, unsigned long *dest)
 781 {
 782         unsigned long data2;
 783
 784         data &= 0x55555555;
 785         data2 = data ^ 0x55555555;
 786         data |= ((data2 >> 1) | 0x80000000) & (data2 << 1);
 787
 788         if (*(dest - 1) & 0x00000001)
 789                 data &= 0x7FFFFFFF;
 790
 791         *dest = data;
 792 }
 793
 794 static void encode_block(unsigned long *dest, unsigned long *src, int len)
 795 {
 796         int cnt, to_cnt = 0;
 797         unsigned long data;
 798
 799         /* odd bits */
 800         for (cnt = 0; cnt < len / 4; cnt++) {
 801                 data = src[cnt] >> 1;
 802                 encode(data, dest + to_cnt++);
 803         }
 804
 805         /* even bits */
 806         for (cnt = 0; cnt < len / 4; cnt++) {
 807                 data = src[cnt];
 808                 encode(data, dest + to_cnt++);
 809         }
 810 }
 811
 812 static unsigned long *putsec(int disk, unsigned long *raw, int cnt)
 813 {
 814         struct header hdr;
 815         int i;
 816
 817         disk&=3;
 818         *raw = (raw[-1]&1) ? 0x2AAAAAAA : 0xAAAAAAAA;
 819         raw++;
 820         *raw++ = 0x44894489;
 821
 822         hdr.magic = 0xFF;
 823         hdr.track = unit[disk].track;
 824         hdr.sect = cnt;
 825         hdr.ord = unit[disk].dtype->sects * unit[disk].type->sect_mult - cnt;
 826         for (i = 0; i < 16; i++)
 827                 hdr.labels[i] = 0;
 828         hdr.hdrchk = checksum((ulong *)&hdr,
 829                               (char *)&hdr.hdrchk-(char *)&hdr);
 830         hdr.datachk = checksum((ulong *)(unit[disk].trackbuf+cnt*512), 512);
 831
 832         encode_block(raw, (ulong *)&hdr.magic, 4);
 833         raw += 2;
 834         encode_block(raw, (ulong *)&hdr.labels, 16);
 835         raw += 8;
 836         encode_block(raw, (ulong *)&hdr.hdrchk, 4);
 837         raw += 2;
 838         encode_block(raw, (ulong *)&hdr.datachk, 4);
 839         raw += 2;
 840         encode_block(raw, (ulong *)(unit[disk].trackbuf+cnt*512), 512);
 841         raw += 256;
 842
 843         return raw;
 844 }
 845
 846 static void amiga_write(int disk)
 847 {
 848         unsigned int cnt;
 849         unsigned long *ptr = (unsigned long *)raw_buf;
 850
 851         disk&=3;
 852         /* gap space */
 853         for (cnt = 0; cnt < 415 * unit[disk].type->sect_mult; cnt++)
 854                 *ptr++ = 0xaaaaaaaa;
 855
 856         /* sectors */
 857         for (cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
 858                 ptr = putsec (disk, ptr, cnt);
 859         *(ushort *)ptr = (ptr[-1]&1) ? 0x2AA8 : 0xAAA8;
 860 }
 861
 862
 863 struct dos_header {
 864         unsigned char track,   /* 0-80 */
 865                 side,    /* 0-1 */
 866                 sec,     /* 0-...*/
 867                 len_desc;/* 2 */
 868         unsigned short crc;     /* on 68000 we got an alignment problem,
 869                                    but this compiler solves it  by adding silently
 870                                    adding a pad byte so data won't fit
 871                                    and this took about 3h to discover.... */
 872         unsigned char gap1[22];     /* for longword-alignedness (0x4e) */
 873 };
 874
 875 /* crc routines are borrowed from the messydos-handler  */
 876
 877 /* excerpt from the messydos-device
 878 ; The CRC is computed not only over the actual data, but including
 879 ; the SYNC mark (3 * $a1) and the 'ID/DATA - Address Mark' ($fe/$fb).
 880 ; As we don't read or encode these fields into our buffers, we have to
 881 ; preload the registers containing the CRC with the values they would have
 882 ; after stepping over these fields.
 883 ;
 884 ; How CRCs "really" work:
 885 ;
 886 ; First, you should regard a bitstring as a series of coefficients of
 887 ; polynomials. We calculate with these polynomials in modulo-2
 888 ; arithmetic, in which both add and subtract are done the same as
 889 ; exclusive-or. Now, we modify our data (a very long polynomial) in
 890 ; such a way that it becomes divisible by the CCITT-standard 16-bit
 891 ;                16   12   5
 892 ; polynomial:   x  + x  + x + 1, represented by $11021. The easiest
 893 ; way to do this would be to multiply (using proper arithmetic) our
 894 ; datablock with $11021. So we have:
 895 ;   data * $11021                =
 896 ;   data * ($10000 + $1021)      =
 897 ;   data * $10000 + data * $1021
 898 ; The left part of this is simple: Just add two 0 bytes. But then
 899 ; the right part (data $1021) remains difficult and even could have
 900 ; a carry into the left part. The solution is to use a modified
 901 ; multiplication, which has a result that is not correct, but with
 902 ; a difference of any multiple of $11021. We then only need to keep
 903 ; the 16 least significant bits of the result.
 904 ;
 905 ; The following algorithm does this for us:
 906 ;
 907 ;   unsigned char *data, c, crclo, crchi;
 908 ;   while (not done) {
 909 ;       c = *data++ + crchi;
 910 ;       crchi = (@ c) >> 8 + crclo;
 911 ;       crclo = @ c;
 912 ;   }
 913 ;
 914 ; Remember, + is done with EOR, the @ operator is in two tables (high
 915 ; and low byte separately), which is calculated as
 916 ;
 917 ;      $1021 * (c & $F0)
 918 ;  xor $1021 * (c & $0F)
 919 ;  xor $1021 * (c >> 4)         (* is regular multiplication)
 920 ;
 921 ;
 922 ; Anyway, the end result is the same as the remainder of the division of
 923 ; the data by $11021. I am afraid I need to study theory a bit more...
 924
 925
 926 my only works was to code this from manx to C....
 927
 928 */
 929
 930 static ushort dos_crc(void * data_a3, int data_d0, int data_d1, int data_d3)
 931 {
 932         static unsigned char CRCTable1[] = {
 933                 0x00,0x10,0x20,0x30,0x40,0x50,0x60,0x70,0x81,0x91,0xa1,0xb1,0xc1,0xd1,0xe1,0xf1,
 934                 0x12,0x02,0x32,0x22,0x52,0x42,0x72,0x62,0x93,0x83,0xb3,0xa3,0xd3,0xc3,0xf3,0xe3,
 935                 0x24,0x34,0x04,0x14,0x64,0x74,0x44,0x54,0xa5,0xb5,0x85,0x95,0xe5,0xf5,0xc5,0xd5,
 936                 0x36,0x26,0x16,0x06,0x76,0x66,0x56,0x46,0xb7,0xa7,0x97,0x87,0xf7,0xe7,0xd7,0xc7,
 937                 0x48,0x58,0x68,0x78,0x08,0x18,0x28,0x38,0xc9,0xd9,0xe9,0xf9,0x89,0x99,0xa9,0xb9,
 938                 0x5a,0x4a,0x7a,0x6a,0x1a,0x0a,0x3a,0x2a,0xdb,0xcb,0xfb,0xeb,0x9b,0x8b,0xbb,0xab,
 939                 0x6c,0x7c,0x4c,0x5c,0x2c,0x3c,0x0c,0x1c,0xed,0xfd,0xcd,0xdd,0xad,0xbd,0x8d,0x9d,
 940                 0x7e,0x6e,0x5e,0x4e,0x3e,0x2e,0x1e,0x0e,0xff,0xef,0xdf,0xcf,0xbf,0xaf,0x9f,0x8f,
 941                 0x91,0x81,0xb1,0xa1,0xd1,0xc1,0xf1,0xe1,0x10,0x00,0x30,0x20,0x50,0x40,0x70,0x60,
 942                 0x83,0x93,0xa3,0xb3,0xc3,0xd3,0xe3,0xf3,0x02,0x12,0x22,0x32,0x42,0x52,0x62,0x72,
 943                 0xb5,0xa5,0x95,0x85,0xf5,0xe5,0xd5,0xc5,0x34,0x24,0x14,0x04,0x74,0x64,0x54,0x44,
 944                 0xa7,0xb7,0x87,0x97,0xe7,0xf7,0xc7,0xd7,0x26,0x36,0x06,0x16,0x66,0x76,0x46,0x56,
 945                 0xd9,0xc9,0xf9,0xe9,0x99,0x89,0xb9,0xa9,0x58,0x48,0x78,0x68,0x18,0x08,0x38,0x28,
 946                 0xcb,0xdb,0xeb,0xfb,0x8b,0x9b,0xab,0xbb,0x4a,0x5a,0x6a,0x7a,0x0a,0x1a,0x2a,0x3a,
 947                 0xfd,0xed,0xdd,0xcd,0xbd,0xad,0x9d,0x8d,0x7c,0x6c,0x5c,0x4c,0x3c,0x2c,0x1c,0x0c,
 948                 0xef,0xff,0xcf,0xdf,0xaf,0xbf,0x8f,0x9f,0x6e,0x7e,0x4e,0x5e,0x2e,0x3e,0x0e,0x1e
 949         };
 950
 951         static unsigned char CRCTable2[] = {
 952                 0x00,0x21,0x42,0x63,0x84,0xa5,0xc6,0xe7,0x08,0x29,0x4a,0x6b,0x8c,0xad,0xce,0xef,
 953                 0x31,0x10,0x73,0x52,0xb5,0x94,0xf7,0xd6,0x39,0x18,0x7b,0x5a,0xbd,0x9c,0xff,0xde,
 954                 0x62,0x43,0x20,0x01,0xe6,0xc7,0xa4,0x85,0x6a,0x4b,0x28,0x09,0xee,0xcf,0xac,0x8d,
 955                 0x53,0x72,0x11,0x30,0xd7,0xf6,0x95,0xb4,0x5b,0x7a,0x19,0x38,0xdf,0xfe,0x9d,0xbc,
 956                 0xc4,0xe5,0x86,0xa7,0x40,0x61,0x02,0x23,0xcc,0xed,0x8e,0xaf,0x48,0x69,0x0a,0x2b,
 957                 0xf5,0xd4,0xb7,0x96,0x71,0x50,0x33,0x12,0xfd,0xdc,0xbf,0x9e,0x79,0x58,0x3b,0x1a,
 958                 0xa6,0x87,0xe4,0xc5,0x22,0x03,0x60,0x41,0xae,0x8f,0xec,0xcd,0x2a,0x0b,0x68,0x49,
 959                 0x97,0xb6,0xd5,0xf4,0x13,0x32,0x51,0x70,0x9f,0xbe,0xdd,0xfc,0x1b,0x3a,0x59,0x78,
 960                 0x88,0xa9,0xca,0xeb,0x0c,0x2d,0x4e,0x6f,0x80,0xa1,0xc2,0xe3,0x04,0x25,0x46,0x67,
 961                 0xb9,0x98,0xfb,0xda,0x3d,0x1c,0x7f,0x5e,0xb1,0x90,0xf3,0xd2,0x35,0x14,0x77,0x56,
 962                 0xea,0xcb,0xa8,0x89,0x6e,0x4f,0x2c,0x0d,0xe2,0xc3,0xa0,0x81,0x66,0x47,0x24,0x05,
 963                 0xdb,0xfa,0x99,0xb8,0x5f,0x7e,0x1d,0x3c,0xd3,0xf2,0x91,0xb0,0x57,0x76,0x15,0x34,
 964                 0x4c,0x6d,0x0e,0x2f,0xc8,0xe9,0x8a,0xab,0x44,0x65,0x06,0x27,0xc0,0xe1,0x82,0xa3,
 965                 0x7d,0x5c,0x3f,0x1e,0xf9,0xd8,0xbb,0x9a,0x75,0x54,0x37,0x16,0xf1,0xd0,0xb3,0x92,
 966                 0x2e,0x0f,0x6c,0x4d,0xaa,0x8b,0xe8,0xc9,0x26,0x07,0x64,0x45,0xa2,0x83,0xe0,0xc1,
 967                 0x1f,0x3e,0x5d,0x7c,0x9b,0xba,0xd9,0xf8,0x17,0x36,0x55,0x74,0x93,0xb2,0xd1,0xf0
 968         };
 969
 970 /* look at the asm-code - what looks in C a bit strange is almost as good as handmade */
 971         register int i;
 972         register unsigned char *CRCT1, *CRCT2, *data, c, crch, crcl;
 973
 974         CRCT1=CRCTable1;
 975         CRCT2=CRCTable2;
 976         data=data_a3;
 977         crcl=data_d1;
 978         crch=data_d0;
 979         for (i=data_d3; i>=0; i--) {
 980                 c = (*data++) ^ crch;
 981                 crch = CRCT1[c] ^ crcl;
 982                 crcl = CRCT2[c];
 983         }
 984         return (crch<<8)|crcl;
 985 }
 986
 987 static inline ushort dos_hdr_crc (struct dos_header *hdr)
 988 {
 989         return dos_crc(&(hdr->track), 0xb2, 0x30, 3); /* precomputed magic */
 990 }
 991
 992 static inline ushort dos_data_crc(unsigned char *data)
 993 {
 994         return dos_crc(data, 0xe2, 0x95 ,511); /* precomputed magic */
 995 }
 996
 997 static inline unsigned char dos_decode_byte(ushort word)
 998 {
 999         register ushort w2;
1000         register unsigned char byte;
1001         register unsigned char *dec = mfmdecode;
1002
1003         w2=word;
1004         w2>>=8;
1005         w2&=127;
1006         byte = dec[w2];
1007         byte <<= 4;
1008         w2 = word & 127;
1009         byte |= dec[w2];
1010         return byte;
1011 }
1012
1013 static unsigned long dos_decode(unsigned char *data, unsigned short *raw, int len)
1014 {
1015         int i;
1016
1017         for (i = 0; i < len; i++)
1018                 *data++=dos_decode_byte(*raw++);
1019         return ((ulong)raw);
1020 }
1021
1022 #ifdef DEBUG
1023 static void dbg(unsigned long ptr)
1024 {
1025         printk("raw data @%08lx: %08lx, %08lx ,%08lx, %08lx\n", ptr,
1026                ((ulong *)ptr)[0], ((ulong *)ptr)[1],
1027                ((ulong *)ptr)[2], ((ulong *)ptr)[3]);
1028 }
1029 #endif
1030
1031 static int dos_read(int drive)
1032 {
1033         unsigned long end;
1034         unsigned long raw;
1035         int scnt;
1036         unsigned short crc,data_crc[2];
1037         struct dos_header hdr;
1038
1039         drive&=3;
1040         raw = (long) raw_buf;
1041         end = raw + unit[drive].type->read_size;
1042
1043         for (scnt=0; scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
1044                 do { /* search for the right sync of each sec-hdr */
1045                         if (!(raw = scan_sync (raw, end))) {
1046                                 printk(KERN_INFO "dos_read: no hdr sync on "
1047                                        "track %d, unit %d for sector %d\n",
1048                                        unit[drive].track,drive,scnt);
1049                                 return MFM_NOSYNC;
1050                         }
1051 #ifdef DEBUG
1052                         dbg(raw);
1053 #endif
1054                 } while (*((ushort *)raw)!=0x5554); /* loop usually only once done */
1055                 raw+=2; /* skip over headermark */
1056                 raw = dos_decode((unsigned char *)&hdr,(ushort *) raw,8);
1057                 crc = dos_hdr_crc(&hdr);
1058
1059 #ifdef DEBUG
1060                 printk("(%3d,%d,%2d,%d) %x\n", hdr.track, hdr.side,
1061                        hdr.sec, hdr.len_desc, hdr.crc);
1062 #endif
1063
1064                 if (crc != hdr.crc) {
1065                         printk(KERN_INFO "dos_read: MFM_HEADER %04x,%04x\n",
1066                                hdr.crc, crc);
1067                         return MFM_HEADER;
1068                 }
1069                 if (hdr.track != unit[drive].track/unit[drive].type->heads) {
1070                         printk(KERN_INFO "dos_read: MFM_TRACK %d, %d\n",
1071                                hdr.track,
1072                                unit[drive].track/unit[drive].type->heads);
1073                         return MFM_TRACK;
1074                 }
1075
1076                 if (hdr.side != unit[drive].track%unit[drive].type->heads) {
1077                         printk(KERN_INFO "dos_read: MFM_SIDE %d, %d\n",
1078                                hdr.side,
1079                                unit[drive].track%unit[drive].type->heads);
1080                         return MFM_TRACK;
1081                 }
1082
1083                 if (hdr.len_desc != 2) {
1084                         printk(KERN_INFO "dos_read: unknown sector len "
1085                                "descriptor %d\n", hdr.len_desc);
1086                         return MFM_DATA;
1087                 }
1088 #ifdef DEBUG
1089                 printk("hdr accepted\n");
1090 #endif
1091                 if (!(raw = scan_sync (raw, end))) {
1092                         printk(KERN_INFO "dos_read: no data sync on track "
1093                                "%d, unit %d for sector%d, disk sector %d\n",
1094                                unit[drive].track, drive, scnt, hdr.sec);
1095                         return MFM_NOSYNC;
1096                 }
1097 #ifdef DEBUG
1098                 dbg(raw);
1099 #endif
1100
1101                 if (*((ushort *)raw)!=0x5545) {
1102                         printk(KERN_INFO "dos_read: no data mark after "
1103                                "sync (%d,%d,%d,%d) sc=%d\n",
1104                                hdr.track,hdr.side,hdr.sec,hdr.len_desc,scnt);
1105                         return MFM_NOSYNC;
1106                 }
1107
1108                 raw+=2;  /* skip data mark (included in checksum) */
1109                 raw = dos_decode((unsigned char *)(unit[drive].trackbuf + (hdr.sec - 1) * 512), (ushort *) raw, 512);
1110                 raw = dos_decode((unsigned char  *)data_crc,(ushort *) raw,4);
1111                 crc = dos_data_crc(unit[drive].trackbuf + (hdr.sec - 1) * 512);
1112
1113                 if (crc != data_crc[0]) {
1114                         printk(KERN_INFO "dos_read: MFM_DATA (%d,%d,%d,%d) "
1115                                "sc=%d, %x %x\n", hdr.track, hdr.side,
1116                                hdr.sec, hdr.len_desc, scnt,data_crc[0], crc);
1117                         printk(KERN_INFO "data=(%lx,%lx,%lx,%lx,...)\n",
1118                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[0],
1119                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[1],
1120                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[2],
1121                                ((ulong *)(unit[drive].trackbuf+(hdr.sec-1)*512))[3]);
1122                         return MFM_DATA;
1123                 }
1124         }
1125         return 0;
1126 }
1127
1128 static inline ushort dos_encode_byte(unsigned char byte)
1129 {
1130         register unsigned char *enc, b2, b1;
1131         register ushort word;
1132
1133         enc=mfmencode;
1134         b1=byte;
1135         b2=b1>>4;
1136         b1&=15;
1137         word=enc[b2] <<8 | enc [b1];
1138         return (word|((word&(256|64)) ? 0: 128));
1139 }
1140
1141 static void dos_encode_block(ushort *dest, unsigned char *src, int len)
1142 {
1143         int i;
1144
1145         for (i = 0; i < len; i++) {
1146                 *dest=dos_encode_byte(*src++);
1147                 *dest|=((dest[-1]&1)||(*dest&0x4000))? 0: 0x8000;
1148                 dest++;
1149         }
1150 }
1151
1152 static unsigned long *ms_putsec(int drive, unsigned long *raw, int cnt)
1153 {
1154         static struct dos_header hdr={0,0,0,2,0,
1155           {78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78}};
1156         int i;
1157         static ushort crc[2]={0,0x4e4e};
1158
1159         drive&=3;
1160 /* id gap 1 */
1161 /* the MFM word before is always 9254 */
1162         for(i=0;i<6;i++)
1163                 *raw++=0xaaaaaaaa;
1164 /* 3 sync + 1 headermark */
1165         *raw++=0x44894489;
1166         *raw++=0x44895554;
1167
1168 /* fill in the variable parts of the header */
1169         hdr.track=unit[drive].track/unit[drive].type->heads;
1170         hdr.side=unit[drive].track%unit[drive].type->heads;
1171         hdr.sec=cnt+1;
1172         hdr.crc=dos_hdr_crc(&hdr);
1173
1174 /* header (without "magic") and id gap 2*/
1175         dos_encode_block((ushort *)raw,(unsigned char *) &hdr.track,28);
1176         raw+=14;
1177
1178 /*id gap 3 */
1179         for(i=0;i<6;i++)
1180                 *raw++=0xaaaaaaaa;
1181
1182 /* 3 syncs and 1 datamark */
1183         *raw++=0x44894489;
1184         *raw++=0x44895545;
1185
1186 /* data */
1187         dos_encode_block((ushort *)raw,
1188                          (unsigned char *)unit[drive].trackbuf+cnt*512,512);
1189         raw+=256;
1190
1191 /*data crc + jd's special gap (long words :-/) */
1192         crc[0]=dos_data_crc(unit[drive].trackbuf+cnt*512);
1193         dos_encode_block((ushort *) raw,(unsigned char *)crc,4);
1194         raw+=2;
1195
1196 /* data gap */
1197         for(i=0;i<38;i++)
1198                 *raw++=0x92549254;
1199
1200         return raw; /* wrote 652 MFM words */
1201 }
1202
1203 static void dos_write(int disk)
1204 {
1205         int cnt;
1206         unsigned long raw = (unsigned long) raw_buf;
1207         unsigned long *ptr=(unsigned long *)raw;
1208
1209         disk&=3;
1210 /* really gap4 + indexgap , but we write it first and round it up */
1211         for (cnt=0;cnt<425;cnt++)
1212                 *ptr++=0x92549254;
1213
1214 /* the following is just guessed */
1215         if (unit[disk].type->sect_mult==2)  /* check for HD-Disks */
1216                 for(cnt=0;cnt<473;cnt++)
1217                         *ptr++=0x92549254;
1218
1219 /* now the index marks...*/
1220         for (cnt=0;cnt<20;cnt++)
1221                 *ptr++=0x92549254;
1222         for (cnt=0;cnt<6;cnt++)
1223                 *ptr++=0xaaaaaaaa;
1224         *ptr++=0x52245224;
1225         *ptr++=0x52245552;
1226         for (cnt=0;cnt<20;cnt++)
1227                 *ptr++=0x92549254;
1228
1229 /* sectors */
1230         for(cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
1231                 ptr=ms_putsec(disk,ptr,cnt);
1232
1233         *(ushort *)ptr = 0xaaa8; /* MFM word before is always 0x9254 */
1234 }
1235
1236 /*
1237  * Here comes the high level stuff (i.e. the filesystem interface)
1238  * and helper functions.
1239  * Normally this should be the only part that has to be adapted to
1240  * different kernel versions.
1241  */
1242
1243 /* FIXME: this assumes the drive is still spinning -
1244  * which is only true if we complete writing a track within three seconds
1245  */
1246 static void flush_track_callback(unsigned long nr)
1247 {
1248         nr&=3;
1249         writefromint = 1;
1250         if (!try_fdc(nr)) {
1251                 /* we might block in an interrupt, so try again later */
1252                 flush_track_timer[nr].expires = jiffies + 1;
1253                 add_timer(flush_track_timer + nr);
1254                 return;
1255         }
1256         get_fdc(nr);
1257         (*unit[nr].dtype->write_fkt)(nr);
1258         if (!raw_write(nr)) {
1259                 printk (KERN_NOTICE "floppy disk write protected\n");
1260                 writefromint = 0;
1261                 writepending = 0;
1262         }
1263         rel_fdc();
1264 }
1265
1266 static int non_int_flush_track (unsigned long nr)
1267 {
1268         unsigned long flags;
1269
1270         nr&=3;
1271         writefromint = 0;
1272         del_timer(&post_write_timer);
1273         get_fdc(nr);
1274         if (!fd_motor_on(nr)) {
1275                 writepending = 0;
1276                 rel_fdc();
1277                 return 0;
1278         }
1279         local_irq_save(flags);
1280         if (writepending != 2) {
1281                 local_irq_restore(flags);
1282                 (*unit[nr].dtype->write_fkt)(nr);
1283                 if (!raw_write(nr)) {
1284                         printk (KERN_NOTICE "floppy disk write protected "
1285                                 "in write!\n");
1286                         writepending = 0;
1287                         return 0;
1288                 }
1289                 wait_event(wait_fd_block, block_flag != 2);
1290         }
1291         else {
1292                 local_irq_restore(flags);
1293                 ms_delay(2); /* 2 ms post_write delay */
1294                 post_write(nr);
1295         }
1296         rel_fdc();
1297         return 1;
1298 }
1299
1300 static int get_track(int drive, int track)
1301 {
1302         int error, errcnt;
1303
1304         drive&=3;
1305         if (unit[drive].track == track)
1306                 return 0;
1307         get_fdc(drive);
1308         if (!fd_motor_on(drive)) {
1309                 rel_fdc();
1310                 return -1;
1311         }
1312
1313         if (unit[drive].dirty == 1) {
1314                 del_timer (flush_track_timer + drive);
1315                 non_int_flush_track (drive);
1316         }
1317         errcnt = 0;
1318         while (errcnt < MAX_ERRORS) {
1319                 if (!fd_seek(drive, track))
1320                         return -1;
1321                 raw_read(drive);
1322                 error = (*unit[drive].dtype->read_fkt)(drive);
1323                 if (error == 0) {
1324                         rel_fdc();
1325                         return 0;
1326                 }
1327                 /* Read Error Handling: recalibrate and try again */
1328                 unit[drive].track = -1;
1329                 errcnt++;
1330         }
1331         rel_fdc();
1332         return -1;
1333 }
1334
1335 static void redo_fd_request(void)
1336 {
1337         struct request *rq;
1338         unsigned int cnt, block, track, sector;
1339         int drive;
1340         struct amiga_floppy_struct *floppy;
1341         char *data;
1342         unsigned long flags;
1343         int err;
1344
1345 next_req:
1346         rq = blk_fetch_request(floppy_queue);
1347         if (!rq) {
1348                 /* Nothing left to do */
1349                 return;
1350         }
1351
1352         floppy = rq->rq_disk->private_data;
1353         drive = floppy - unit;
1354
1355 next_segment:
1356         /* Here someone could investigate to be more efficient */
1357         for (cnt = 0, err = 0; cnt < blk_rq_cur_sectors(rq); cnt++) {
1358 #ifdef DEBUG
1359                 printk("fd: sector %ld + %d requested for %s\n",
1360                        blk_rq_pos(rq), cnt,
1361                        (rq_data_dir(rq) == READ) ? "read" : "write");
1362 #endif
1363                 block = blk_rq_pos(rq) + cnt;
1364                 if ((int)block > floppy->blocks) {
1365                         err = -EIO;
1366                         break;
1367                 }
1368
1369                 track = block / (floppy->dtype->sects * floppy->type->sect_mult);
1370                 sector = block % (floppy->dtype->sects * floppy->type->sect_mult);
1371                 data = rq->buffer + 512 * cnt;
1372 #ifdef DEBUG
1373                 printk("access to track %d, sector %d, with buffer at "
1374                        "0x%08lx\n", track, sector, data);
1375 #endif
1376
1377                 if (get_track(drive, track) == -1) {
1378                         err = -EIO;
1379                         break;
1380                 }
1381
1382                 if (rq_data_dir(rq) == READ) {
1383                         memcpy(data, floppy->trackbuf + sector * 512, 512);
1384                 } else {
1385                         memcpy(floppy->trackbuf + sector * 512, data, 512);
1386
1387                         /* keep the drive spinning while writes are scheduled */
1388                         if (!fd_motor_on(drive)) {
1389                                 err = -EIO;
1390                                 break;
1391                         }
1392                         /*
1393                          * setup a callback to write the track buffer
1394                          * after a short (1 tick) delay.
1395                          */
1396                         local_irq_save(flags);
1397
1398                         floppy->dirty = 1;
1399                         /* reset the timer */
1400                         mod_timer (flush_track_timer + drive, jiffies + 1);
1401                         local_irq_restore(flags);
1402                 }
1403         }
1404
1405         if (__blk_end_request_cur(rq, err))
1406                 goto next_segment;
1407         goto next_req;
1408 }
1409
1410 static void do_fd_request(struct request_queue * q)
1411 {
1412         redo_fd_request();
1413 }
1414
1415 static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1416 {
1417         int drive = MINOR(bdev->bd_dev) & 3;
1418
1419         geo->heads = unit[drive].type->heads;
1420         geo->sectors = unit[drive].dtype->sects * unit[drive].type->sect_mult;
1421         geo->cylinders = unit[drive].type->tracks;
1422         return 0;
1423 }
1424
1425 static int fd_ioctl(struct block_device *bdev, fmode_t mode,
1426                     unsigned int cmd, unsigned long param)
1427 {
1428         struct amiga_floppy_struct *p = bdev->bd_disk->private_data;
1429         int drive = p - unit;
1430         static struct floppy_struct getprm;
1431         void __user *argp = (void __user *)param;
1432
1433         switch(cmd){
1434         case FDFMTBEG:
1435                 get_fdc(drive);
1436                 if (fd_ref[drive] > 1) {
1437                         rel_fdc();
1438                         return -EBUSY;
1439                 }
1440                 fsync_bdev(bdev);
1441                 if (fd_motor_on(drive) == 0) {
1442                         rel_fdc();
1443                         return -ENODEV;
1444                 }
1445                 if (fd_calibrate(drive) == 0) {
1446                         rel_fdc();
1447                         return -ENXIO;
1448                 }
1449                 floppy_off(drive);
1450                 rel_fdc();
1451                 break;
1452         case FDFMTTRK:
1453                 if (param < p->type->tracks * p->type->heads)
1454                 {
1455                         get_fdc(drive);
1456                         if (fd_seek(drive,param) != 0){
1457                                 memset(p->trackbuf, FD_FILL_BYTE,
1458                                        p->dtype->sects * p->type->sect_mult * 512);
1459                                 non_int_flush_track(drive);
1460                         }
1461                         floppy_off(drive);
1462                         rel_fdc();
1463                 }
1464                 else
1465                         return -EINVAL;
1466                 break;
1467         case FDFMTEND:
1468                 floppy_off(drive);
1469                 invalidate_bdev(bdev);
1470                 break;
1471         case FDGETPRM:
1472                 memset((void *)&getprm, 0, sizeof (getprm));
1473                 getprm.track=p->type->tracks;
1474                 getprm.head=p->type->heads;
1475                 getprm.sect=p->dtype->sects * p->type->sect_mult;
1476                 getprm.size=p->blocks;
1477                 if (copy_to_user(argp, &getprm, sizeof(struct floppy_struct)))
1478                         return -EFAULT;
1479                 break;
1480         case FDSETPRM:
1481         case FDDEFPRM:
1482                 return -EINVAL;
1483         case FDFLUSH: /* unconditionally, even if not needed */
1484                 del_timer (flush_track_timer + drive);
1485                 non_int_flush_track(drive);
1486                 break;
1487 #ifdef RAW_IOCTL
1488         case IOCTL_RAW_TRACK:
1489                 if (copy_to_user(argp, raw_buf, p->type->read_size))
1490                         return -EFAULT;
1491                 else
1492                         return p->type->read_size;
1493 #endif
1494         default:
1495                 printk(KERN_DEBUG "fd_ioctl: unknown cmd %d for drive %d.",
1496                        cmd, drive);
1497                 return -ENOSYS;
1498         }
1499         return 0;
1500 }
1501
1502 static void fd_probe(int dev)
1503 {
1504         unsigned long code;
1505         int type;
1506         int drive;
1507
1508         drive = dev & 3;
1509         code = fd_get_drive_id(drive);
1510
1511         /* get drive type */
1512         for (type = 0; type < num_dr_types; type++)
1513                 if (drive_types[type].code == code)
1514                         break;
1515
1516         if (type >= num_dr_types) {
1517                 printk(KERN_WARNING "fd_probe: unsupported drive type "
1518                        "%08lx found\n", code);
1519                 unit[drive].type = &drive_types[num_dr_types-1]; /* FD_NODRIVE */
1520                 return;
1521         }
1522
1523         unit[drive].type = drive_types + type;
1524         unit[drive].track = -1;
1525
1526         unit[drive].disk = -1;
1527         unit[drive].motor = 0;
1528         unit[drive].busy = 0;
1529         unit[drive].status = -1;
1530 }
1531
1532 /*
1533  * floppy_open check for aliasing (/dev/fd0 can be the same as
1534  * /dev/PS0 etc), and disallows simultaneous access to the same
1535  * drive with different device numbers.
1536  */
1537 static int floppy_open(struct block_device *bdev, fmode_t mode)
1538 {
1539         int drive = MINOR(bdev->bd_dev) & 3;
1540         int system =  (MINOR(bdev->bd_dev) & 4) >> 2;
1541         int old_dev;
1542         unsigned long flags;
1543
1544         old_dev = fd_device[drive];
1545
1546         if (fd_ref[drive] && old_dev != system)
1547                 return -EBUSY;
1548
1549         if (mode & (FMODE_READ|FMODE_WRITE)) {
1550                 check_disk_change(bdev);
1551                 if (mode & FMODE_WRITE) {
1552                         int wrprot;
1553
1554                         get_fdc(drive);
1555                         fd_select (drive);
1556                         wrprot = !(ciaa.pra & DSKPROT);
1557                         fd_deselect (drive);
1558                         rel_fdc();
1559
1560                         if (wrprot)
1561                                 return -EROFS;
1562                 }
1563         }
1564
1565         local_irq_save(flags);
1566         fd_ref[drive]++;
1567         fd_device[drive] = system;
1568         local_irq_restore(flags);
1569
1570         unit[drive].dtype=&data_types[system];
1571         unit[drive].blocks=unit[drive].type->heads*unit[drive].type->tracks*
1572                 data_types[system].sects*unit[drive].type->sect_mult;
1573         set_capacity(unit[drive].gendisk, unit[drive].blocks);
1574
1575         printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
1576                unit[drive].type->name, data_types[system].name);
1577
1578         return 0;
1579 }
1580
1581 static int floppy_release(struct gendisk *disk, fmode_t mode)
1582 {
1583         struct amiga_floppy_struct *p = disk->private_data;
1584         int drive = p - unit;
1585
1586         if (unit[drive].dirty == 1) {
1587                 del_timer (flush_track_timer + drive);
1588                 non_int_flush_track (drive);
1589         }
1590
1591         if (!fd_ref[drive]--) {
1592                 printk(KERN_CRIT "floppy_release with fd_ref == 0");
1593                 fd_ref[drive] = 0;
1594         }
1595 #ifdef MODULE
1596 /* the mod_use counter is handled this way */
1597         floppy_off (drive | 0x40000000);
1598 #endif
1599         return 0;
1600 }
1601
1602 /*
1603  * floppy-change is never called from an interrupt, so we can relax a bit
1604  * here, sleep etc. Note that floppy-on tries to set current_DOR to point
1605  * to the desired drive, but it will probably not survive the sleep if
1606  * several floppies are used at the same time: thus the loop.
1607  */
1608 static int amiga_floppy_change(struct gendisk *disk)
1609 {
1610         struct amiga_floppy_struct *p = disk->private_data;
1611         int drive = p - unit;
1612         int changed;
1613         static int first_time = 1;
1614
1615         if (first_time)
1616                 changed = first_time--;
1617         else {
1618                 get_fdc(drive);
1619                 fd_select (drive);
1620                 changed = !(ciaa.pra & DSKCHANGE);
1621                 fd_deselect (drive);
1622                 rel_fdc();
1623         }
1624
1625         if (changed) {
1626                 fd_probe(drive);
1627                 p->track = -1;
1628                 p->dirty = 0;
1629                 writepending = 0; /* if this was true before, too bad! */
1630                 writefromint = 0;
1631                 return 1;
1632         }
1633         return 0;
1634 }
1635
1636 static const struct block_device_operations floppy_fops = {
1637         .owner          = THIS_MODULE,
1638         .open           = floppy_open,
1639         .release        = floppy_release,
1640         .locked_ioctl   = fd_ioctl,
1641         .getgeo         = fd_getgeo,
1642         .media_changed  = amiga_floppy_change,
1643 };
1644
1645 static int __init fd_probe_drives(void)
1646 {
1647         int drive,drives,nomem;
1648
1649         printk(KERN_INFO "FD: probing units\nfound ");
1650         drives=0;
1651         nomem=0;
1652         for(drive=0;drive<FD_MAX_UNITS;drive++) {
1653                 struct gendisk *disk;
1654                 fd_probe(drive);
1655                 if (unit[drive].type->code == FD_NODRIVE)
1656                         continue;
1657                 disk = alloc_disk(1);
1658                 if (!disk) {
1659                         unit[drive].type->code = FD_NODRIVE;
1660                         continue;
1661                 }
1662                 unit[drive].gendisk = disk;
1663                 drives++;
1664                 if ((unit[drive].trackbuf = kmalloc(FLOPPY_MAX_SECTORS * 512, GFP_KERNEL)) == NULL) {
1665                         printk("no mem for ");
1666                         unit[drive].type = &drive_types[num_dr_types - 1]; /* FD_NODRIVE */
1667                         drives--;
1668                         nomem = 1;
1669                 }
1670                 printk("fd%d ",drive);
1671                 disk->major = FLOPPY_MAJOR;
1672                 disk->first_minor = drive;
1673                 disk->fops = &floppy_fops;
1674                 sprintf(disk->disk_name, "fd%d", drive);
1675                 disk->private_data = &unit[drive];
1676                 disk->queue = floppy_queue;
1677                 set_capacity(disk, 880*2);
1678                 add_disk(disk);
1679         }
1680         if ((drives > 0) || (nomem == 0)) {
1681                 if (drives == 0)
1682                         printk("no drives");
1683                 printk("\n");
1684                 return drives;
1685         }
1686         printk("\n");
1687         return -ENOMEM;
1688 }
1689
1690 static struct kobject *floppy_find(dev_t dev, int *part, void *data)
1691 {
1692         int drive = *part & 3;
1693         if (unit[drive].type->code == FD_NODRIVE)
1694                 return NULL;
1695         *part = 0;
1696         return get_disk(unit[drive].gendisk);
1697 }
1698
1699 static int __init amiga_floppy_init(void)
1700 {
1701         int i, ret;
1702
1703         if (!MACH_IS_AMIGA)
1704                 return -ENODEV;
1705
1706         if (!AMIGAHW_PRESENT(AMI_FLOPPY))
1707                 return -ENODEV;
1708
1709         if (register_blkdev(FLOPPY_MAJOR,"fd"))
1710                 return -EBUSY;
1711
1712         /*
1713          *  We request DSKPTR, DSKLEN and DSKDATA only, because the other
1714          *  floppy registers are too spreaded over the custom register space
1715          */
1716         ret = -EBUSY;
1717         if (!request_mem_region(CUSTOM_PHYSADDR+0x20, 8, "amiflop [Paula]")) {
1718                 printk("fd: cannot get floppy registers\n");
1719                 goto out_blkdev;
1720         }
1721
1722         ret = -ENOMEM;
1723         if ((raw_buf = (char *)amiga_chip_alloc (RAW_BUF_SIZE, "Floppy")) ==
1724             NULL) {
1725                 printk("fd: cannot get chip mem buffer\n");
1726                 goto out_memregion;
1727         }
1728
1729         ret = -EBUSY;
1730         if (request_irq(IRQ_AMIGA_DSKBLK, fd_block_done, 0, "floppy_dma", NULL)) {
1731                 printk("fd: cannot get irq for dma\n");
1732                 goto out_irq;
1733         }
1734
1735         if (request_irq(IRQ_AMIGA_CIAA_TB, ms_isr, 0, "floppy_timer", NULL)) {
1736                 printk("fd: cannot get irq for timer\n");
1737                 goto out_irq2;
1738         }
1739
1740         ret = -ENOMEM;
1741         floppy_queue = blk_init_queue(do_fd_request, &amiflop_lock);
1742         if (!floppy_queue)
1743                 goto out_queue;
1744
1745         ret = -ENODEV;
1746         if (fd_probe_drives() < 1) /* No usable drives */
1747                 goto out_probe;
1748
1749         blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
1750                                 floppy_find, NULL, NULL);
1751
1752         /* initialize variables */
1753         init_timer(&motor_on_timer);
1754         motor_on_timer.expires = 0;
1755         motor_on_timer.data = 0;
1756         motor_on_timer.function = motor_on_callback;
1757         for (i = 0; i < FD_MAX_UNITS; i++) {
1758                 init_timer(&motor_off_timer[i]);
1759                 motor_off_timer[i].expires = 0;
1760                 motor_off_timer[i].data = i|0x80000000;
1761                 motor_off_timer[i].function = fd_motor_off;
1762                 init_timer(&flush_track_timer[i]);
1763                 flush_track_timer[i].expires = 0;
1764                 flush_track_timer[i].data = i;
1765                 flush_track_timer[i].function = flush_track_callback;
1766
1767                 unit[i].track = -1;
1768         }
1769
1770         init_timer(&post_write_timer);
1771         post_write_timer.expires = 0;
1772         post_write_timer.data = 0;
1773         post_write_timer.function = post_write;
1774
1775         for (i = 0; i < 128; i++)
1776                 mfmdecode[i]=255;
1777         for (i = 0; i < 16; i++)
1778                 mfmdecode[mfmencode[i]]=i;
1779
1780         /* make sure that disk DMA is enabled */
1781         custom.dmacon = DMAF_SETCLR | DMAF_DISK;
1782
1783         /* init ms timer */
1784         ciaa.crb = 8; /* one-shot, stop */
1785         return 0;
1786
1787 out_probe:
1788         blk_cleanup_queue(floppy_queue);
1789 out_queue:
1790         free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1791 out_irq2:
1792         free_irq(IRQ_AMIGA_DSKBLK, NULL);
1793 out_irq:
1794         amiga_chip_free(raw_buf);
1795 out_memregion:
1796         release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1797 out_blkdev:
1798         unregister_blkdev(FLOPPY_MAJOR,"fd");
1799         return ret;
1800 }
1801
1802 module_init(amiga_floppy_init);
1803 #ifdef MODULE
1804
1805 #if 0 /* not safe to unload */
1806 void cleanup_module(void)
1807 {
1808         int i;
1809
1810         for( i = 0; i < FD_MAX_UNITS; i++) {
1811                 if (unit[i].type->code != FD_NODRIVE) {
1812                         del_gendisk(unit[i].gendisk);
1813                         put_disk(unit[i].gendisk);
1814                         kfree(unit[i].trackbuf);
1815                 }
1816         }
1817         blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
1818         free_irq(IRQ_AMIGA_CIAA_TB, NULL);
1819         free_irq(IRQ_AMIGA_DSKBLK, NULL);
1820         custom.dmacon = DMAF_DISK; /* disable DMA */
1821         amiga_chip_free(raw_buf);
1822         blk_cleanup_queue(floppy_queue);
1823         release_mem_region(CUSTOM_PHYSADDR+0x20, 8);
1824         unregister_blkdev(FLOPPY_MAJOR, "fd");
1825 }
1826 #endif
1827
1828 #else
1829 static int __init amiga_floppy_setup (char *str)
1830 {
1831         int n;
1832         if (!MACH_IS_AMIGA)
1833                 return 0;
1834         if (!get_option(&str, &n))
1835                 return 0;
1836         printk (KERN_INFO "amiflop: Setting default df0 to %x\n", n);
1837         fd_def_df0 = n;
1838         return 1;
1839 }
1840
1841 __setup("floppy=", amiga_floppy_setup);
1842 #endif