drivers/ide/legacy/hd.c

   1 /*
   2  *  linux/drivers/ide/legacy/hd.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  * This is the low-level hd interrupt support. It traverses the
   9  * request-list, using interrupts to jump between functions. As
  10  * all the functions are called within interrupts, we may not
  11  * sleep. Special care is recommended.
  12  *
  13  *  modified by Drew Eckhardt to check nr of hd's from the CMOS.
  14  *
  15  *  Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
  16  *  in the early extended-partition checks and added DM partitions
  17  *
  18  *  IRQ-unmask, drive-id, multiple-mode, support for ">16 heads",
  19  *  and general streamlining by Mark Lord.
  20  *
  21  *  Removed 99% of above. Use Mark's ide driver for those options.
  22  *  This is now a lightweight ST-506 driver. (Paul Gortmaker)
  23  *
  24  *  Modified 1995 Russell King for ARM processor.
  25  *
  26  *  Bugfix: max_sectors must be <= 255 or the wheels tend to come
  27  *  off in a hurry once you queue things up - Paul G. 02/2001
  28  */
  29
  30 /* Uncomment the following if you want verbose error reports. */
  31 /* #define VERBOSE_ERRORS */
  32
  33 #include <linux/errno.h>
  34 #include <linux/signal.h>
  35 #include <linux/sched.h>
  36 #include <linux/timer.h>
  37 #include <linux/fs.h>
  38 #include <linux/devfs_fs_kernel.h>
  39 #include <linux/kernel.h>
  40 #include <linux/hdreg.h>
  41 #include <linux/genhd.h>
  42 #include <linux/slab.h>
  43 #include <linux/string.h>
  44 #include <linux/ioport.h>
  45 #include <linux/mc146818rtc.h> /* CMOS defines */
  46 #include <linux/init.h>
  47 #include <linux/blkpg.h>
  48
  49 #define REALLY_SLOW_IO
  50 #include <asm/system.h>
  51 #include <asm/io.h>
  52 #include <asm/uaccess.h>
  53
  54 #define MAJOR_NR HD_MAJOR
  55 #include <linux/blk.h>
  56
  57 #ifdef __arm__
  58 #undef  HD_IRQ
  59 #endif
  60 #include <asm/irq.h>
  61 #ifdef __arm__
  62 #define HD_IRQ IRQ_HARDDISK
  63 #endif
  64
  65 static int revalidate_hddisk(kdev_t, int);
  66
  67 #define HD_DELAY        0
  68
  69 #define MAX_ERRORS     16       /* Max read/write errors/sector */
  70 #define RESET_FREQ      8       /* Reset controller every 8th retry */
  71 #define RECAL_FREQ      4       /* Recalibrate every 4th retry */
  72 #define MAX_HD          2
  73
  74 #define STAT_OK         (READY_STAT|SEEK_STAT)
  75 #define OK_STATUS(s)    (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
  76
  77 static void recal_intr(void);
  78 static void bad_rw_intr(void);
  79
  80 static char recalibrate[MAX_HD];
  81 static char special_op[MAX_HD];
  82 static int access_count[MAX_HD];
  83 static char busy[MAX_HD];
  84 static DECLARE_WAIT_QUEUE_HEAD(busy_wait);
  85
  86 static int reset;
  87 static int hd_error;
  88
  89 #define SUBSECTOR(block) (CURRENT->current_nr_sectors > 0)
  90
  91 /*
  92  *  This struct defines the HD's and their types.
  93  */
  94 struct hd_i_struct {
  95         unsigned int head,sect,cyl,wpcom,lzone,ctl;
  96 };
  97
  98 #ifdef HD_TYPE
  99 static struct hd_i_struct hd_info[] = { HD_TYPE };
 100 static int NR_HD = ((sizeof (hd_info))/(sizeof (struct hd_i_struct)));
 101 #else
 102 static struct hd_i_struct hd_info[MAX_HD];
 103 static int NR_HD;
 104 #endif
 105
 106 static struct hd_struct hd[MAX_HD<<6];
 107 static int hd_sizes[MAX_HD<<6];
 108 static int hd_blocksizes[MAX_HD<<6];
 109 static int hd_hardsectsizes[MAX_HD<<6];
 110 static int hd_maxsect[MAX_HD<<6];
 111
 112 static struct timer_list device_timer;
 113
 114 #define SET_TIMER                                                       \
 115         do {                                                            \
 116                 mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);      \
 117         } while (0)
 118
 119 #define CLEAR_TIMER del_timer(&device_timer);
 120
 121 #undef SET_INTR
 122
 123 #define SET_INTR(x) \
 124 if ((DEVICE_INTR = (x)) != NULL) \
 125         SET_TIMER; \
 126 else \
 127         CLEAR_TIMER;
 128
 129
 130 #if (HD_DELAY > 0)
 131 unsigned long last_req;
 132
 133 unsigned long read_timer(void)
 134 {
 135         unsigned long t, flags;
 136         int i;
 137
 138         spin_lock_irqsave(&io_request_lock, flags);
 139         t = jiffies * 11932;
 140         outb_p(0, 0x43);
 141         i = inb_p(0x40);
 142         i |= inb(0x40) << 8;
 143         spin_unlock_irqrestore(&io_request_lock, flags);
 144         return(t - i);
 145 }
 146 #endif
 147
 148 void __init hd_setup(char *str, int *ints)
 149 {
 150         int hdind = 0;
 151
 152         if (ints[0] != 3)
 153                 return;
 154         if (hd_info[0].head != 0)
 155                 hdind=1;
 156         hd_info[hdind].head = ints[2];
 157         hd_info[hdind].sect = ints[3];
 158         hd_info[hdind].cyl = ints[1];
 159         hd_info[hdind].wpcom = 0;
 160         hd_info[hdind].lzone = ints[1];
 161         hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
 162         NR_HD = hdind+1;
 163 }
 164
 165 static void dump_status (const char *msg, unsigned int stat)
 166 {
 167         unsigned long flags;
 168         char devc;
 169
 170         devc = !QUEUE_EMPTY ? 'a' + DEVICE_NR(CURRENT->rq_dev) : '?';
 171         save_flags (flags);
 172         sti();
 173 #ifdef VERBOSE_ERRORS
 174         printk("hd%c: %s: status=0x%02x { ", devc, msg, stat & 0xff);
 175         if (stat & BUSY_STAT)   printk("Busy ");
 176         if (stat & READY_STAT)  printk("DriveReady ");
 177         if (stat & WRERR_STAT)  printk("WriteFault ");
 178         if (stat & SEEK_STAT)   printk("SeekComplete ");
 179         if (stat & DRQ_STAT)    printk("DataRequest ");
 180         if (stat & ECC_STAT)    printk("CorrectedError ");
 181         if (stat & INDEX_STAT)  printk("Index ");
 182         if (stat & ERR_STAT)    printk("Error ");
 183         printk("}\n");
 184         if ((stat & ERR_STAT) == 0) {
 185                 hd_error = 0;
 186         } else {
 187                 hd_error = inb(HD_ERROR);
 188                 printk("hd%c: %s: error=0x%02x { ", devc, msg, hd_error & 0xff);
 189                 if (hd_error & BBD_ERR)         printk("BadSector ");
 190                 if (hd_error & ECC_ERR)         printk("UncorrectableError ");
 191                 if (hd_error & ID_ERR)          printk("SectorIdNotFound ");
 192                 if (hd_error & ABRT_ERR)        printk("DriveStatusError ");
 193                 if (hd_error & TRK0_ERR)        printk("TrackZeroNotFound ");
 194                 if (hd_error & MARK_ERR)        printk("AddrMarkNotFound ");
 195                 printk("}");
 196                 if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
 197                         printk(", CHS=%d/%d/%d",
 198                                 (inb(HD_HCYL)<<8) + inb(HD_LCYL),
 199                                 inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
 200                         if (!QUEUE_EMPTY)
 201                                 printk(", sector=%ld", CURRENT->sector);
 202                 }
 203                 printk("\n");
 204         }
 205 #else
 206         printk("hd%c: %s: status=0x%02x.\n", devc, msg, stat & 0xff);
 207         if ((stat & ERR_STAT) == 0) {
 208                 hd_error = 0;
 209         } else {
 210                 hd_error = inb(HD_ERROR);
 211                 printk("hd%c: %s: error=0x%02x.\n", devc, msg, hd_error & 0xff);
 212         }
 213 #endif  /* verbose errors */
 214         restore_flags (flags);
 215 }
 216
 217 void check_status(void)
 218 {
 219         int i = inb_p(HD_STATUS);
 220
 221         if (!OK_STATUS(i)) {
 222                 dump_status("check_status", i);
 223                 bad_rw_intr();
 224         }
 225 }
 226
 227 static int controller_busy(void)
 228 {
 229         int retries = 100000;
 230         unsigned char status;
 231
 232         do {
 233                 status = inb_p(HD_STATUS);
 234         } while ((status & BUSY_STAT) && --retries);
 235         return status;
 236 }
 237
 238 static int status_ok(void)
 239 {
 240         unsigned char status = inb_p(HD_STATUS);
 241
 242         if (status & BUSY_STAT)
 243                 return 1;       /* Ancient, but does it make sense??? */
 244         if (status & WRERR_STAT)
 245                 return 0;
 246         if (!(status & READY_STAT))
 247                 return 0;
 248         if (!(status & SEEK_STAT))
 249                 return 0;
 250         return 1;
 251 }
 252
 253 static int controller_ready(unsigned int drive, unsigned int head)
 254 {
 255         int retry = 100;
 256
 257         do {
 258                 if (controller_busy() & BUSY_STAT)
 259                         return 0;
 260                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 261                 if (status_ok())
 262                         return 1;
 263         } while (--retry);
 264         return 0;
 265 }
 266
 267 static void hd_out(unsigned int drive,unsigned int nsect,unsigned int sect,
 268                 unsigned int head,unsigned int cyl,unsigned int cmd,
 269                 void (*intr_addr)(void))
 270 {
 271         unsigned short port;
 272
 273 #if (HD_DELAY > 0)
 274         while (read_timer() - last_req < HD_DELAY)
 275                 /* nothing */;
 276 #endif
 277         if (reset)
 278                 return;
 279         if (!controller_ready(drive, head)) {
 280                 reset = 1;
 281                 return;
 282         }
 283         SET_INTR(intr_addr);
 284         outb_p(hd_info[drive].ctl,HD_CMD);
 285         port=HD_DATA;
 286         outb_p(hd_info[drive].wpcom>>2,++port);
 287         outb_p(nsect,++port);
 288         outb_p(sect,++port);
 289         outb_p(cyl,++port);
 290         outb_p(cyl>>8,++port);
 291         outb_p(0xA0|(drive<<4)|head,++port);
 292         outb_p(cmd,++port);
 293 }
 294
 295 static void hd_request (void);
 296
 297 static int drive_busy(void)
 298 {
 299         unsigned int i;
 300         unsigned char c;
 301
 302         for (i = 0; i < 500000 ; i++) {
 303                 c = inb_p(HD_STATUS);
 304                 if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
 305                         return 0;
 306         }
 307         dump_status("reset timed out", c);
 308         return 1;
 309 }
 310
 311 static void reset_controller(void)
 312 {
 313         int     i;
 314
 315         outb_p(4,HD_CMD);
 316         for(i = 0; i < 1000; i++) barrier();
 317         outb_p(hd_info[0].ctl & 0x0f,HD_CMD);
 318         for(i = 0; i < 1000; i++) barrier();
 319         if (drive_busy())
 320                 printk("hd: controller still busy\n");
 321         else if ((hd_error = inb(HD_ERROR)) != 1)
 322                 printk("hd: controller reset failed: %02x\n",hd_error);
 323 }
 324
 325 static void reset_hd(void)
 326 {
 327         static int i;
 328
 329 repeat:
 330         if (reset) {
 331                 reset = 0;
 332                 i = -1;
 333                 reset_controller();
 334         } else {
 335                 check_status();
 336                 if (reset)
 337                         goto repeat;
 338         }
 339         if (++i < NR_HD) {
 340                 special_op[i] = recalibrate[i] = 1;
 341                 hd_out(i,hd_info[i].sect,hd_info[i].sect,hd_info[i].head-1,
 342                         hd_info[i].cyl,WIN_SPECIFY,&reset_hd);
 343                 if (reset)
 344                         goto repeat;
 345         } else
 346                 hd_request();
 347 }
 348
 349 void do_reset_hd(void)
 350 {
 351         DEVICE_INTR = NULL;
 352         reset = 1;
 353         reset_hd();
 354 }
 355
 356 /*
 357  * Ok, don't know what to do with the unexpected interrupts: on some machines
 358  * doing a reset and a retry seems to result in an eternal loop. Right now I
 359  * ignore it, and just set the timeout.
 360  *
 361  * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 362  * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 363  * "good", we just ignore the interrupt completely.
 364  */
 365 void unexpected_hd_interrupt(void)
 366 {
 367         unsigned int stat = inb_p(HD_STATUS);
 368
 369         if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
 370                 dump_status ("unexpected interrupt", stat);
 371                 SET_TIMER;
 372         }
 373 }
 374
 375 /*
 376  * bad_rw_intr() now tries to be a bit smarter and does things
 377  * according to the error returned by the controller.
 378  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 379  */
 380 static void bad_rw_intr(void)
 381 {
 382         int dev;
 383
 384         if (QUEUE_EMPTY)
 385                 return;
 386         dev = DEVICE_NR(CURRENT->rq_dev);
 387         if (++CURRENT->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 388                 end_request(0);
 389                 special_op[dev] = recalibrate[dev] = 1;
 390         } else if (CURRENT->errors % RESET_FREQ == 0)
 391                 reset = 1;
 392         else if ((hd_error & TRK0_ERR) || CURRENT->errors % RECAL_FREQ == 0)
 393                 special_op[dev] = recalibrate[dev] = 1;
 394         /* Otherwise just retry */
 395 }
 396
 397 static inline int wait_DRQ(void)
 398 {
 399         int retries = 100000, stat;
 400
 401         while (--retries > 0)
 402                 if ((stat = inb_p(HD_STATUS)) & DRQ_STAT)
 403                         return 0;
 404         dump_status("wait_DRQ", stat);
 405         return -1;
 406 }
 407
 408 static void read_intr(void)
 409 {
 410         int i, retries = 100000;
 411
 412         do {
 413                 i = (unsigned) inb_p(HD_STATUS);
 414                 if (i & BUSY_STAT)
 415                         continue;
 416                 if (!OK_STATUS(i))
 417                         break;
 418                 if (i & DRQ_STAT)
 419                         goto ok_to_read;
 420         } while (--retries > 0);
 421         dump_status("read_intr", i);
 422         bad_rw_intr();
 423         hd_request();
 424         return;
 425 ok_to_read:
 426         insw(HD_DATA,CURRENT->buffer,256);
 427         CURRENT->sector++;
 428         CURRENT->buffer += 512;
 429         CURRENT->errors = 0;
 430         i = --CURRENT->nr_sectors;
 431         --CURRENT->current_nr_sectors;
 432 #ifdef DEBUG
 433         printk("hd%c: read: sector %ld, remaining = %ld, buffer=0x%08lx\n",
 434                 dev+'a', CURRENT->sector, CURRENT->nr_sectors,
 435                 (unsigned long) CURRENT->buffer+512));
 436 #endif
 437         if (CURRENT->current_nr_sectors <= 0)
 438                 end_request(1);
 439         if (i > 0) {
 440                 SET_INTR(&read_intr);
 441                 return;
 442         }
 443         (void) inb_p(HD_STATUS);
 444 #if (HD_DELAY > 0)
 445         last_req = read_timer();
 446 #endif
 447         if (!QUEUE_EMPTY)
 448                 hd_request();
 449         return;
 450 }
 451
 452 static void write_intr(void)
 453 {
 454         int i;
 455         int retries = 100000;
 456
 457         do {
 458                 i = (unsigned) inb_p(HD_STATUS);
 459                 if (i & BUSY_STAT)
 460                         continue;
 461                 if (!OK_STATUS(i))
 462                         break;
 463                 if ((CURRENT->nr_sectors <= 1) || (i & DRQ_STAT))
 464                         goto ok_to_write;
 465         } while (--retries > 0);
 466         dump_status("write_intr", i);
 467         bad_rw_intr();
 468         hd_request();
 469         return;
 470 ok_to_write:
 471         CURRENT->sector++;
 472         i = --CURRENT->nr_sectors;
 473         --CURRENT->current_nr_sectors;
 474         CURRENT->buffer += 512;
 475         if (!i || (CURRENT->bh && !SUBSECTOR(i)))
 476                 end_request(1);
 477         if (i > 0) {
 478                 SET_INTR(&write_intr);
 479                 outsw(HD_DATA,CURRENT->buffer,256);
 480                 sti();
 481         } else {
 482 #if (HD_DELAY > 0)
 483                 last_req = read_timer();
 484 #endif
 485                 hd_request();
 486         }
 487         return;
 488 }
 489
 490 static void recal_intr(void)
 491 {
 492         check_status();
 493 #if (HD_DELAY > 0)
 494         last_req = read_timer();
 495 #endif
 496         hd_request();
 497 }
 498
 499 /*
 500  * This is another of the error-routines I don't know what to do with. The
 501  * best idea seems to just set reset, and start all over again.
 502  */
 503 static void hd_times_out(unsigned long dummy)
 504 {
 505         unsigned int dev;
 506
 507         DEVICE_INTR = NULL;
 508         if (QUEUE_EMPTY)
 509                 return;
 510         disable_irq(HD_IRQ);
 511         sti();
 512         reset = 1;
 513         dev = DEVICE_NR(CURRENT->rq_dev);
 514         printk("hd%c: timeout\n", dev+'a');
 515         if (++CURRENT->errors >= MAX_ERRORS) {
 516 #ifdef DEBUG
 517                 printk("hd%c: too many errors\n", dev+'a');
 518 #endif
 519                 end_request(0);
 520         }
 521         cli();
 522         hd_request();
 523         enable_irq(HD_IRQ);
 524 }
 525
 526 int do_special_op (unsigned int dev)
 527 {
 528         if (recalibrate[dev]) {
 529                 recalibrate[dev] = 0;
 530                 hd_out(dev,hd_info[dev].sect,0,0,0,WIN_RESTORE,&recal_intr);
 531                 return reset;
 532         }
 533         if (hd_info[dev].head > 16) {
 534                 printk ("hd%c: cannot handle device with more than 16 heads - giving up\n", dev+'a');
 535                 end_request(0);
 536         }
 537         special_op[dev] = 0;
 538         return 1;
 539 }
 540
 541 /*
 542  * The driver enables interrupts as much as possible.  In order to do this,
 543  * (a) the device-interrupt is disabled before entering hd_request(),
 544  * and (b) the timeout-interrupt is disabled before the sti().
 545  *
 546  * Interrupts are still masked (by default) whenever we are exchanging
 547  * data/cmds with a drive, because some drives seem to have very poor
 548  * tolerance for latency during I/O. The IDE driver has support to unmask
 549  * interrupts for non-broken hardware, so use that driver if required.
 550  */
 551 static void hd_request(void)
 552 {
 553         unsigned int dev, block, nsect, sec, track, head, cyl;
 554
 555         if (!QUEUE_EMPTY && CURRENT->rq_status == RQ_INACTIVE) return;
 556         if (DEVICE_INTR)
 557                 return;
 558 repeat:
 559         del_timer(&device_timer);
 560         sti();
 561         INIT_REQUEST;
 562         if (reset) {
 563                 cli();
 564                 reset_hd();
 565                 return;
 566         }
 567         dev = MINOR(CURRENT->rq_dev);
 568         block = CURRENT->sector;
 569         nsect = CURRENT->nr_sectors;
 570         if (dev >= (NR_HD<<6) || block >= hd[dev].nr_sects || ((block+nsect) > hd[dev].nr_sects)) {
 571 #ifdef DEBUG
 572                 if (dev >= (NR_HD<<6))
 573                         printk("hd: bad minor number: device=%s\n",
 574                                kdevname(CURRENT->rq_dev));
 575                 else
 576                         printk("hd%c: bad access: block=%d, count=%d\n",
 577                                 (MINOR(CURRENT->rq_dev)>>6)+'a', block, nsect);
 578 #endif
 579                 end_request(0);
 580                 goto repeat;
 581         }
 582         block += hd[dev].start_sect;
 583         dev >>= 6;
 584         if (special_op[dev]) {
 585                 if (do_special_op(dev))
 586                         goto repeat;
 587                 return;
 588         }
 589         sec   = block % hd_info[dev].sect + 1;
 590         track = block / hd_info[dev].sect;
 591         head  = track % hd_info[dev].head;
 592         cyl   = track / hd_info[dev].head;
 593 #ifdef DEBUG
 594         printk("hd%c: %sing: CHS=%d/%d/%d, sectors=%d, buffer=0x%08lx\n",
 595                 dev+'a', (CURRENT->cmd == READ)?"read":"writ",
 596                 cyl, head, sec, nsect, (unsigned long) CURRENT->buffer);
 597 #endif
 598         if (CURRENT->cmd == READ) {
 599                 hd_out(dev,nsect,sec,head,cyl,WIN_READ,&read_intr);
 600                 if (reset)
 601                         goto repeat;
 602                 return;
 603         }
 604         if (CURRENT->cmd == WRITE) {
 605                 hd_out(dev,nsect,sec,head,cyl,WIN_WRITE,&write_intr);
 606                 if (reset)
 607                         goto repeat;
 608                 if (wait_DRQ()) {
 609                         bad_rw_intr();
 610                         goto repeat;
 611                 }
 612                 outsw(HD_DATA,CURRENT->buffer,256);
 613                 return;
 614         }
 615         panic("unknown hd-command");
 616 }
 617
 618 static void do_hd_request (request_queue_t * q)
 619 {
 620         disable_irq(HD_IRQ);
 621         hd_request();
 622         enable_irq(HD_IRQ);
 623 }
 624
 625 static int hd_ioctl(struct inode * inode, struct file * file,
 626         unsigned int cmd, unsigned long arg)
 627 {
 628         struct hd_geometry *loc = (struct hd_geometry *) arg;
 629         int dev;
 630
 631         if ((!inode) || !(inode->i_rdev))
 632                 return -EINVAL;
 633         dev = DEVICE_NR(inode->i_rdev);
 634         if (dev >= NR_HD)
 635                 return -EINVAL;
 636         switch (cmd) {
 637                 case HDIO_GETGEO:
 638                 {
 639                         struct hd_geometry g;
 640                         if (!loc)  return -EINVAL;
 641                         g.heads = hd_info[dev].head;
 642                         g.sectors = hd_info[dev].sect;
 643                         g.cylinders = hd_info[dev].cyl;
 644                         g.start = hd[MINOR(inode->i_rdev)].start_sect;
 645                         return copy_to_user(loc, &g, sizeof g) ? -EFAULT : 0;
 646                 }
 647
 648                 case BLKGETSIZE:   /* Return device size */
 649                         return put_user(hd[MINOR(inode->i_rdev)].nr_sects,
 650                                         (unsigned long *) arg);
 651                 case BLKGETSIZE64:
 652                         return put_user((u64)hd[MINOR(inode->i_rdev)].nr_sects << 9,
 653                                         (u64 *) arg);
 654
 655                 case BLKRRPART: /* Re-read partition tables */
 656                         if (!capable(CAP_SYS_ADMIN))
 657                                 return -EACCES;
 658                         return revalidate_hddisk(inode->i_rdev, 1);
 659
 660                 case BLKROSET:
 661                 case BLKROGET:
 662                 case BLKRASET:
 663                 case BLKRAGET:
 664                 case BLKFLSBUF:
 665                 case BLKPG:
 666                         return blk_ioctl(inode->i_rdev, cmd, arg);
 667
 668                 default:
 669                         return -EINVAL;
 670         }
 671 }
 672
 673 static int hd_open(struct inode * inode, struct file * filp)
 674 {
 675         int target;
 676         target =  DEVICE_NR(inode->i_rdev);
 677
 678         if (target >= NR_HD)
 679                 return -ENODEV;
 680         while (busy[target])
 681                 sleep_on(&busy_wait);
 682         access_count[target]++;
 683         return 0;
 684 }
 685
 686 /*
 687  * Releasing a block device means we sync() it, so that it can safely
 688  * be forgotten about...
 689  */
 690 static int hd_release(struct inode * inode, struct file * file)
 691 {
 692         int target =  DEVICE_NR(inode->i_rdev);
 693         access_count[target]--;
 694         return 0;
 695 }
 696
 697 static struct block_device_operations hd_fops = {
 698         open:           hd_open,
 699         release:        hd_release,
 700         ioctl:          hd_ioctl,
 701 };
 702
 703 static struct gendisk hd_gendisk = {
 704         major:          MAJOR_NR,
 705         major_name:     "hd",
 706         minor_shift:    6,
 707         max_p:          1 << 6,
 708         part:           hd,
 709         sizes:          hd_sizes,
 710         fops:           &hd_fops,
 711 };
 712
 713 static void hd_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 714 {
 715         void (*handler)(void) = DEVICE_INTR;
 716
 717         DEVICE_INTR = NULL;
 718         del_timer(&device_timer);
 719         if (!handler)
 720                 handler = unexpected_hd_interrupt;
 721         handler();
 722         sti();
 723 }
 724
 725 /*
 726  * This is the hard disk IRQ description. The SA_INTERRUPT in sa_flags
 727  * means we run the IRQ-handler with interrupts disabled:  this is bad for
 728  * interrupt latency, but anything else has led to problems on some
 729  * machines.
 730  *
 731  * We enable interrupts in some of the routines after making sure it's
 732  * safe.
 733  */
 734 static void __init hd_geninit(void)
 735 {
 736         int drive;
 737
 738         for(drive=0; drive < (MAX_HD << 6); drive++) {
 739                 hd_blocksizes[drive] = 1024;
 740                 hd_hardsectsizes[drive] = 512;
 741                 hd_maxsect[drive]=255;
 742         }
 743         blksize_size[MAJOR_NR] = hd_blocksizes;
 744         hardsect_size[MAJOR_NR] = hd_hardsectsizes;
 745         max_sectors[MAJOR_NR] = hd_maxsect;
 746
 747 #ifdef __i386__
 748         if (!NR_HD) {
 749                 extern struct drive_info drive_info;
 750                 unsigned char *BIOS = (unsigned char *) &drive_info;
 751                 unsigned long flags;
 752                 int cmos_disks;
 753
 754                 for (drive=0 ; drive<2 ; drive++) {
 755                         hd_info[drive].cyl = *(unsigned short *) BIOS;
 756                         hd_info[drive].head = *(2+BIOS);
 757                         hd_info[drive].wpcom = *(unsigned short *) (5+BIOS);
 758                         hd_info[drive].ctl = *(8+BIOS);
 759                         hd_info[drive].lzone = *(unsigned short *) (12+BIOS);
 760                         hd_info[drive].sect = *(14+BIOS);
 761 #ifdef does_not_work_for_everybody_with_scsi_but_helps_ibm_vp
 762                         if (hd_info[drive].cyl && NR_HD == drive)
 763                                 NR_HD++;
 764 #endif
 765                         BIOS += 16;
 766                 }
 767
 768         /*
 769                 We query CMOS about hard disks : it could be that
 770                 we have a SCSI/ESDI/etc controller that is BIOS
 771                 compatible with ST-506, and thus showing up in our
 772                 BIOS table, but not register compatible, and therefore
 773                 not present in CMOS.
 774
 775                 Furthermore, we will assume that our ST-506 drives
 776                 <if any> are the primary drives in the system, and
 777                 the ones reflected as drive 1 or 2.
 778
 779                 The first drive is stored in the high nibble of CMOS
 780                 byte 0x12, the second in the low nibble.  This will be
 781                 either a 4 bit drive type or 0xf indicating use byte 0x19
 782                 for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.
 783
 784                 Needless to say, a non-zero value means we have
 785                 an AT controller hard disk for that drive.
 786
 787                 Currently the rtc_lock is a bit academic since this
 788                 driver is non-modular, but someday... ?         Paul G.
 789         */
 790
 791                 spin_lock_irqsave(&rtc_lock, flags);
 792                 cmos_disks = CMOS_READ(0x12);
 793                 spin_unlock_irqrestore(&rtc_lock, flags);
 794
 795                 if (cmos_disks & 0xf0) {
 796                         if (cmos_disks & 0x0f)
 797                                 NR_HD = 2;
 798                         else
 799                                 NR_HD = 1;
 800                 }
 801         }
 802 #endif /* __i386__ */
 803 #ifdef __arm__
 804         if (!NR_HD) {
 805                 /* We don't know anything about the drive.  This means
 806                  * that you *MUST* specify the drive parameters to the
 807                  * kernel yourself.
 808                  */
 809                 printk("hd: no drives specified - use hd=cyl,head,sectors"
 810                         " on kernel command line\n");
 811         }
 812 #endif
 813
 814         for (drive=0 ; drive < NR_HD ; drive++) {
 815                 hd[drive<<6].nr_sects = hd_info[drive].head *
 816                         hd_info[drive].sect * hd_info[drive].cyl;
 817                 printk ("hd%c: %ldMB, CHS=%d/%d/%d\n", drive+'a',
 818                         hd[drive<<6].nr_sects / 2048, hd_info[drive].cyl,
 819                         hd_info[drive].head, hd_info[drive].sect);
 820         }
 821         if (!NR_HD)
 822                 return;
 823
 824         if (request_irq(HD_IRQ, hd_interrupt, SA_INTERRUPT, "hd", NULL)) {
 825                 printk("hd: unable to get IRQ%d for the hard disk driver\n",
 826                         HD_IRQ);
 827                 NR_HD = 0;
 828                 return;
 829         }
 830         request_region(HD_DATA, 8, "hd");
 831         request_region(HD_CMD, 1, "hd(cmd)");
 832
 833         hd_gendisk.nr_real = NR_HD;
 834
 835         for(drive=0; drive < NR_HD; drive++)
 836                 register_disk(&hd_gendisk, MKDEV(MAJOR_NR,drive<<6), 1<<6,
 837                         &hd_fops, hd_info[drive].head * hd_info[drive].sect *
 838                         hd_info[drive].cyl);
 839 }
 840
 841 int __init hd_init(void)
 842 {
 843         if (devfs_register_blkdev(MAJOR_NR,"hd",&hd_fops)) {
 844                 printk("hd: unable to get major %d for hard disk\n",MAJOR_NR);
 845                 return -1;
 846         }
 847         blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), DEVICE_REQUEST);
 848         read_ahead[MAJOR_NR] = 8;               /* 8 sector (4kB) read-ahead */
 849         add_gendisk(&hd_gendisk);
 850         init_timer(&device_timer);
 851         device_timer.function = hd_times_out;
 852         hd_geninit();
 853         return 0;
 854 }
 855
 856 #define DEVICE_BUSY busy[target]
 857 #define USAGE access_count[target]
 858 #define CAPACITY (hd_info[target].head*hd_info[target].sect*hd_info[target].cyl)
 859 /* We assume that the BIOS parameters do not change, so the disk capacity
 860    will not change */
 861 #undef MAYBE_REINIT
 862 #define GENDISK_STRUCT hd_gendisk
 863
 864 /*
 865  * This routine is called to flush all partitions and partition tables
 866  * for a changed disk, and then re-read the new partition table.
 867  * If we are revalidating a disk because of a media change, then we
 868  * enter with usage == 0.  If we are using an ioctl, we automatically have
 869  * usage == 1 (we need an open channel to use an ioctl :-), so this
 870  * is our limit.
 871  */
 872 static int revalidate_hddisk(kdev_t dev, int maxusage)
 873 {
 874         int target;
 875         struct gendisk * gdev;
 876         int max_p;
 877         int start;
 878         int i;
 879         long flags;
 880
 881         target = DEVICE_NR(dev);
 882         gdev = &GENDISK_STRUCT;
 883
 884         spin_lock_irqsave(&io_request_lock, flags);
 885         if (DEVICE_BUSY || USAGE > maxusage) {
 886                 spin_unlock_irqrestore(&io_request_lock, flags);
 887                 return -EBUSY;
 888         }
 889         DEVICE_BUSY = 1;
 890         spin_unlock_irqrestore(&io_request_lock, flags);
 891
 892         max_p = gdev->max_p;
 893         start = target << gdev->minor_shift;
 894
 895         for (i=max_p - 1; i >=0 ; i--) {
 896                 int minor = start + i;
 897                 invalidate_device(MKDEV(MAJOR_NR, minor), 1);
 898                 gdev->part[minor].start_sect = 0;
 899                 gdev->part[minor].nr_sects = 0;
 900         }
 901
 902 #ifdef MAYBE_REINIT
 903         MAYBE_REINIT;
 904 #endif
 905
 906         grok_partitions(gdev, target, 1<<6, CAPACITY);
 907
 908         DEVICE_BUSY = 0;
 909         wake_up(&busy_wait);
 910         return 0;
 911 }
 912
 913 static int parse_hd_setup (char *line) {
 914         int ints[6];
 915
 916         (void) get_options(line, ARRAY_SIZE(ints), ints);
 917         hd_setup(NULL, ints);
 918
 919         return 1;
 920 }
 921 __setup("hd=", parse_hd_setup);
 922
 923 module_init(hd_init);