drivers/ide/legacy/hd.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *
   4  * This is the low-level hd interrupt support. It traverses the
   5  * request-list, using interrupts to jump between functions. As
   6  * all the functions are called within interrupts, we may not
   7  * sleep. Special care is recommended.
   8  *
   9  *  modified by Drew Eckhardt to check nr of hd's from the CMOS.
  10  *
  11  *  Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
  12  *  in the early extended-partition checks and added DM partitions
  13  *
  14  *  IRQ-unmask, drive-id, multiple-mode, support for ">16 heads",
  15  *  and general streamlining by Mark Lord.
  16  *
  17  *  Removed 99% of above. Use Mark's ide driver for those options.
  18  *  This is now a lightweight ST-506 driver. (Paul Gortmaker)
  19  *
  20  *  Modified 1995 Russell King for ARM processor.
  21  *
  22  *  Bugfix: max_sectors must be <= 255 or the wheels tend to come
  23  *  off in a hurry once you queue things up - Paul G. 02/2001
  24  */
  25
  26 /* Uncomment the following if you want verbose error reports. */
  27 /* #define VERBOSE_ERRORS */
  28
  29 #include <linux/blkdev.h>
  30 #include <linux/errno.h>
  31 #include <linux/signal.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/timer.h>
  34 #include <linux/fs.h>
  35 #include <linux/kernel.h>
  36 #include <linux/genhd.h>
  37 #include <linux/slab.h>
  38 #include <linux/string.h>
  39 #include <linux/ioport.h>
  40 #include <linux/mc146818rtc.h> /* CMOS defines */
  41 #include <linux/init.h>
  42 #include <linux/blkpg.h>
  43 #include <linux/hdreg.h>
  44
  45 #define REALLY_SLOW_IO
  46 #include <asm/system.h>
  47 #include <asm/io.h>
  48 #include <asm/uaccess.h>
  49
  50 #ifdef __arm__
  51 #undef  HD_IRQ
  52 #endif
  53 #include <asm/irq.h>
  54 #ifdef __arm__
  55 #define HD_IRQ IRQ_HARDDISK
  56 #endif
  57
  58 /* Hd controller regster ports */
  59
  60 #define HD_DATA         0x1f0           /* _CTL when writing */
  61 #define HD_ERROR        0x1f1           /* see err-bits */
  62 #define HD_NSECTOR      0x1f2           /* nr of sectors to read/write */
  63 #define HD_SECTOR       0x1f3           /* starting sector */
  64 #define HD_LCYL         0x1f4           /* starting cylinder */
  65 #define HD_HCYL         0x1f5           /* high byte of starting cyl */
  66 #define HD_CURRENT      0x1f6           /* 101dhhhh , d=drive, hhhh=head */
  67 #define HD_STATUS       0x1f7           /* see status-bits */
  68 #define HD_FEATURE      HD_ERROR        /* same io address, read=error, write=feature */
  69 #define HD_PRECOMP      HD_FEATURE      /* obsolete use of this port - predates IDE */
  70 #define HD_COMMAND      HD_STATUS       /* same io address, read=status, write=cmd */
  71
  72 #define HD_CMD          0x3f6           /* used for resets */
  73 #define HD_ALTSTATUS    0x3f6           /* same as HD_STATUS but doesn't clear irq */
  74
  75 /* Bits of HD_STATUS */
  76 #define ERR_STAT                0x01
  77 #define INDEX_STAT              0x02
  78 #define ECC_STAT                0x04    /* Corrected error */
  79 #define DRQ_STAT                0x08
  80 #define SEEK_STAT               0x10
  81 #define SERVICE_STAT            SEEK_STAT
  82 #define WRERR_STAT              0x20
  83 #define READY_STAT              0x40
  84 #define BUSY_STAT               0x80
  85
  86 /* Bits for HD_ERROR */
  87 #define MARK_ERR                0x01    /* Bad address mark */
  88 #define TRK0_ERR                0x02    /* couldn't find track 0 */
  89 #define ABRT_ERR                0x04    /* Command aborted */
  90 #define MCR_ERR                 0x08    /* media change request */
  91 #define ID_ERR                  0x10    /* ID field not found */
  92 #define MC_ERR                  0x20    /* media changed */
  93 #define ECC_ERR                 0x40    /* Uncorrectable ECC error */
  94 #define BBD_ERR                 0x80    /* pre-EIDE meaning:  block marked bad */
  95 #define ICRC_ERR                0x80    /* new meaning:  CRC error during transfer */
  96
  97 static DEFINE_SPINLOCK(hd_lock);
  98 static struct request_queue *hd_queue;
  99
 100 #define MAJOR_NR HD_MAJOR
 101 #define QUEUE (hd_queue)
 102 #define CURRENT elv_next_request(hd_queue)
 103
 104 #define TIMEOUT_VALUE   (6*HZ)
 105 #define HD_DELAY        0
 106
 107 #define MAX_ERRORS     16       /* Max read/write errors/sector */
 108 #define RESET_FREQ      8       /* Reset controller every 8th retry */
 109 #define RECAL_FREQ      4       /* Recalibrate every 4th retry */
 110 #define MAX_HD          2
 111
 112 #define STAT_OK         (READY_STAT|SEEK_STAT)
 113 #define OK_STATUS(s)    (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
 114
 115 static void recal_intr(void);
 116 static void bad_rw_intr(void);
 117
 118 static int reset;
 119 static int hd_error;
 120
 121 /*
 122  *  This struct defines the HD's and their types.
 123  */
 124 struct hd_i_struct {
 125         unsigned int head, sect, cyl, wpcom, lzone, ctl;
 126         int unit;
 127         int recalibrate;
 128         int special_op;
 129 };
 130
 131 #ifdef HD_TYPE
 132 static struct hd_i_struct hd_info[] = { HD_TYPE };
 133 static int NR_HD = ARRAY_SIZE(hd_info);
 134 #else
 135 static struct hd_i_struct hd_info[MAX_HD];
 136 static int NR_HD;
 137 #endif
 138
 139 static struct gendisk *hd_gendisk[MAX_HD];
 140
 141 static struct timer_list device_timer;
 142
 143 #define TIMEOUT_VALUE (6*HZ)
 144
 145 #define SET_TIMER                                                       \
 146         do {                                                            \
 147                 mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);      \
 148         } while (0)
 149
 150 static void (*do_hd)(void) = NULL;
 151 #define SET_HANDLER(x) \
 152 if ((do_hd = (x)) != NULL) \
 153         SET_TIMER; \
 154 else \
 155         del_timer(&device_timer);
 156
 157
 158 #if (HD_DELAY > 0)
 159
 160 #include <asm/i8253.h>
 161
 162 unsigned long last_req;
 163
 164 unsigned long read_timer(void)
 165 {
 166         unsigned long t, flags;
 167         int i;
 168
 169         spin_lock_irqsave(&i8253_lock, flags);
 170         t = jiffies * 11932;
 171         outb_p(0, 0x43);
 172         i = inb_p(0x40);
 173         i |= inb(0x40) << 8;
 174         spin_unlock_irqrestore(&i8253_lock, flags);
 175         return(t - i);
 176 }
 177 #endif
 178
 179 static void __init hd_setup(char *str, int *ints)
 180 {
 181         int hdind = 0;
 182
 183         if (ints[0] != 3)
 184                 return;
 185         if (hd_info[0].head != 0)
 186                 hdind = 1;
 187         hd_info[hdind].head = ints[2];
 188         hd_info[hdind].sect = ints[3];
 189         hd_info[hdind].cyl = ints[1];
 190         hd_info[hdind].wpcom = 0;
 191         hd_info[hdind].lzone = ints[1];
 192         hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
 193         NR_HD = hdind+1;
 194 }
 195
 196 static void dump_status(const char *msg, unsigned int stat)
 197 {
 198         char *name = "hd?";
 199         if (CURRENT)
 200                 name = CURRENT->rq_disk->disk_name;
 201
 202 #ifdef VERBOSE_ERRORS
 203         printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
 204         if (stat & BUSY_STAT)   printk("Busy ");
 205         if (stat & READY_STAT)  printk("DriveReady ");
 206         if (stat & WRERR_STAT)  printk("WriteFault ");
 207         if (stat & SEEK_STAT)   printk("SeekComplete ");
 208         if (stat & DRQ_STAT)    printk("DataRequest ");
 209         if (stat & ECC_STAT)    printk("CorrectedError ");
 210         if (stat & INDEX_STAT)  printk("Index ");
 211         if (stat & ERR_STAT)    printk("Error ");
 212         printk("}\n");
 213         if ((stat & ERR_STAT) == 0) {
 214                 hd_error = 0;
 215         } else {
 216                 hd_error = inb(HD_ERROR);
 217                 printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
 218                 if (hd_error & BBD_ERR)         printk("BadSector ");
 219                 if (hd_error & ECC_ERR)         printk("UncorrectableError ");
 220                 if (hd_error & ID_ERR)          printk("SectorIdNotFound ");
 221                 if (hd_error & ABRT_ERR)        printk("DriveStatusError ");
 222                 if (hd_error & TRK0_ERR)        printk("TrackZeroNotFound ");
 223                 if (hd_error & MARK_ERR)        printk("AddrMarkNotFound ");
 224                 printk("}");
 225                 if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
 226                         printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
 227                                 inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
 228                         if (CURRENT)
 229                                 printk(", sector=%ld", CURRENT->sector);
 230                 }
 231                 printk("\n");
 232         }
 233 #else
 234         printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
 235         if ((stat & ERR_STAT) == 0) {
 236                 hd_error = 0;
 237         } else {
 238                 hd_error = inb(HD_ERROR);
 239                 printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
 240         }
 241 #endif
 242 }
 243
 244 static void check_status(void)
 245 {
 246         int i = inb_p(HD_STATUS);
 247
 248         if (!OK_STATUS(i)) {
 249                 dump_status("check_status", i);
 250                 bad_rw_intr();
 251         }
 252 }
 253
 254 static int controller_busy(void)
 255 {
 256         int retries = 100000;
 257         unsigned char status;
 258
 259         do {
 260                 status = inb_p(HD_STATUS);
 261         } while ((status & BUSY_STAT) && --retries);
 262         return status;
 263 }
 264
 265 static int status_ok(void)
 266 {
 267         unsigned char status = inb_p(HD_STATUS);
 268
 269         if (status & BUSY_STAT)
 270                 return 1;       /* Ancient, but does it make sense??? */
 271         if (status & WRERR_STAT)
 272                 return 0;
 273         if (!(status & READY_STAT))
 274                 return 0;
 275         if (!(status & SEEK_STAT))
 276                 return 0;
 277         return 1;
 278 }
 279
 280 static int controller_ready(unsigned int drive, unsigned int head)
 281 {
 282         int retry = 100;
 283
 284         do {
 285                 if (controller_busy() & BUSY_STAT)
 286                         return 0;
 287                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 288                 if (status_ok())
 289                         return 1;
 290         } while (--retry);
 291         return 0;
 292 }
 293
 294 static void hd_out(struct hd_i_struct *disk,
 295                    unsigned int nsect,
 296                    unsigned int sect,
 297                    unsigned int head,
 298                    unsigned int cyl,
 299                    unsigned int cmd,
 300                    void (*intr_addr)(void))
 301 {
 302         unsigned short port;
 303
 304 #if (HD_DELAY > 0)
 305         while (read_timer() - last_req < HD_DELAY)
 306                 /* nothing */;
 307 #endif
 308         if (reset)
 309                 return;
 310         if (!controller_ready(disk->unit, head)) {
 311                 reset = 1;
 312                 return;
 313         }
 314         SET_HANDLER(intr_addr);
 315         outb_p(disk->ctl, HD_CMD);
 316         port = HD_DATA;
 317         outb_p(disk->wpcom >> 2, ++port);
 318         outb_p(nsect, ++port);
 319         outb_p(sect, ++port);
 320         outb_p(cyl, ++port);
 321         outb_p(cyl >> 8, ++port);
 322         outb_p(0xA0 | (disk->unit << 4) | head, ++port);
 323         outb_p(cmd, ++port);
 324 }
 325
 326 static void hd_request (void);
 327
 328 static int drive_busy(void)
 329 {
 330         unsigned int i;
 331         unsigned char c;
 332
 333         for (i = 0; i < 500000 ; i++) {
 334                 c = inb_p(HD_STATUS);
 335                 if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
 336                         return 0;
 337         }
 338         dump_status("reset timed out", c);
 339         return 1;
 340 }
 341
 342 static void reset_controller(void)
 343 {
 344         int     i;
 345
 346         outb_p(4, HD_CMD);
 347         for (i = 0; i < 1000; i++) barrier();
 348         outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
 349         for (i = 0; i < 1000; i++) barrier();
 350         if (drive_busy())
 351                 printk("hd: controller still busy\n");
 352         else if ((hd_error = inb(HD_ERROR)) != 1)
 353                 printk("hd: controller reset failed: %02x\n", hd_error);
 354 }
 355
 356 static void reset_hd(void)
 357 {
 358         static int i;
 359
 360 repeat:
 361         if (reset) {
 362                 reset = 0;
 363                 i = -1;
 364                 reset_controller();
 365         } else {
 366                 check_status();
 367                 if (reset)
 368                         goto repeat;
 369         }
 370         if (++i < NR_HD) {
 371                 struct hd_i_struct *disk = &hd_info[i];
 372                 disk->special_op = disk->recalibrate = 1;
 373                 hd_out(disk, disk->sect, disk->sect, disk->head-1,
 374                         disk->cyl, WIN_SPECIFY, &reset_hd);
 375                 if (reset)
 376                         goto repeat;
 377         } else
 378                 hd_request();
 379 }
 380
 381 /*
 382  * Ok, don't know what to do with the unexpected interrupts: on some machines
 383  * doing a reset and a retry seems to result in an eternal loop. Right now I
 384  * ignore it, and just set the timeout.
 385  *
 386  * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 387  * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 388  * "good", we just ignore the interrupt completely.
 389  */
 390 static void unexpected_hd_interrupt(void)
 391 {
 392         unsigned int stat = inb_p(HD_STATUS);
 393
 394         if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
 395                 dump_status("unexpected interrupt", stat);
 396                 SET_TIMER;
 397         }
 398 }
 399
 400 /*
 401  * bad_rw_intr() now tries to be a bit smarter and does things
 402  * according to the error returned by the controller.
 403  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 404  */
 405 static void bad_rw_intr(void)
 406 {
 407         struct request *req = CURRENT;
 408         if (req != NULL) {
 409                 struct hd_i_struct *disk = req->rq_disk->private_data;
 410                 if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 411                         end_request(req, 0);
 412                         disk->special_op = disk->recalibrate = 1;
 413                 } else if (req->errors % RESET_FREQ == 0)
 414                         reset = 1;
 415                 else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
 416                         disk->special_op = disk->recalibrate = 1;
 417                 /* Otherwise just retry */
 418         }
 419 }
 420
 421 static inline int wait_DRQ(void)
 422 {
 423         int retries;
 424         int stat;
 425
 426         for (retries = 0; retries < 100000; retries++) {
 427                 stat = inb_p(HD_STATUS);
 428                 if (stat & DRQ_STAT)
 429                         return 0;
 430         }
 431         dump_status("wait_DRQ", stat);
 432         return -1;
 433 }
 434
 435 static void read_intr(void)
 436 {
 437         struct request *req;
 438         int i, retries = 100000;
 439
 440         do {
 441                 i = (unsigned) inb_p(HD_STATUS);
 442                 if (i & BUSY_STAT)
 443                         continue;
 444                 if (!OK_STATUS(i))
 445                         break;
 446                 if (i & DRQ_STAT)
 447                         goto ok_to_read;
 448         } while (--retries > 0);
 449         dump_status("read_intr", i);
 450         bad_rw_intr();
 451         hd_request();
 452         return;
 453 ok_to_read:
 454         req = CURRENT;
 455         insw(HD_DATA, req->buffer, 256);
 456         req->sector++;
 457         req->buffer += 512;
 458         req->errors = 0;
 459         i = --req->nr_sectors;
 460         --req->current_nr_sectors;
 461 #ifdef DEBUG
 462         printk("%s: read: sector %ld, remaining = %ld, buffer=%p\n",
 463                 req->rq_disk->disk_name, req->sector, req->nr_sectors,
 464                 req->buffer+512);
 465 #endif
 466         if (req->current_nr_sectors <= 0)
 467                 end_request(req, 1);
 468         if (i > 0) {
 469                 SET_HANDLER(&read_intr);
 470                 return;
 471         }
 472         (void) inb_p(HD_STATUS);
 473 #if (HD_DELAY > 0)
 474         last_req = read_timer();
 475 #endif
 476         if (elv_next_request(QUEUE))
 477                 hd_request();
 478         return;
 479 }
 480
 481 static void write_intr(void)
 482 {
 483         struct request *req = CURRENT;
 484         int i;
 485         int retries = 100000;
 486
 487         do {
 488                 i = (unsigned) inb_p(HD_STATUS);
 489                 if (i & BUSY_STAT)
 490                         continue;
 491                 if (!OK_STATUS(i))
 492                         break;
 493                 if ((req->nr_sectors <= 1) || (i & DRQ_STAT))
 494                         goto ok_to_write;
 495         } while (--retries > 0);
 496         dump_status("write_intr", i);
 497         bad_rw_intr();
 498         hd_request();
 499         return;
 500 ok_to_write:
 501         req->sector++;
 502         i = --req->nr_sectors;
 503         --req->current_nr_sectors;
 504         req->buffer += 512;
 505         if (!i || (req->bio && req->current_nr_sectors <= 0))
 506                 end_request(req, 1);
 507         if (i > 0) {
 508                 SET_HANDLER(&write_intr);
 509                 outsw(HD_DATA, req->buffer, 256);
 510                 local_irq_enable();
 511         } else {
 512 #if (HD_DELAY > 0)
 513                 last_req = read_timer();
 514 #endif
 515                 hd_request();
 516         }
 517         return;
 518 }
 519
 520 static void recal_intr(void)
 521 {
 522         check_status();
 523 #if (HD_DELAY > 0)
 524         last_req = read_timer();
 525 #endif
 526         hd_request();
 527 }
 528
 529 /*
 530  * This is another of the error-routines I don't know what to do with. The
 531  * best idea seems to just set reset, and start all over again.
 532  */
 533 static void hd_times_out(unsigned long dummy)
 534 {
 535         char *name;
 536
 537         do_hd = NULL;
 538
 539         if (!CURRENT)
 540                 return;
 541
 542         disable_irq(HD_IRQ);
 543         local_irq_enable();
 544         reset = 1;
 545         name = CURRENT->rq_disk->disk_name;
 546         printk("%s: timeout\n", name);
 547         if (++CURRENT->errors >= MAX_ERRORS) {
 548 #ifdef DEBUG
 549                 printk("%s: too many errors\n", name);
 550 #endif
 551                 end_request(CURRENT, 0);
 552         }
 553         local_irq_disable();
 554         hd_request();
 555         enable_irq(HD_IRQ);
 556 }
 557
 558 static int do_special_op(struct hd_i_struct *disk, struct request *req)
 559 {
 560         if (disk->recalibrate) {
 561                 disk->recalibrate = 0;
 562                 hd_out(disk, disk->sect, 0, 0, 0, WIN_RESTORE, &recal_intr);
 563                 return reset;
 564         }
 565         if (disk->head > 16) {
 566                 printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
 567                 end_request(req, 0);
 568         }
 569         disk->special_op = 0;
 570         return 1;
 571 }
 572
 573 /*
 574  * The driver enables interrupts as much as possible.  In order to do this,
 575  * (a) the device-interrupt is disabled before entering hd_request(),
 576  * and (b) the timeout-interrupt is disabled before the sti().
 577  *
 578  * Interrupts are still masked (by default) whenever we are exchanging
 579  * data/cmds with a drive, because some drives seem to have very poor
 580  * tolerance for latency during I/O. The IDE driver has support to unmask
 581  * interrupts for non-broken hardware, so use that driver if required.
 582  */
 583 static void hd_request(void)
 584 {
 585         unsigned int block, nsect, sec, track, head, cyl;
 586         struct hd_i_struct *disk;
 587         struct request *req;
 588
 589         if (do_hd)
 590                 return;
 591 repeat:
 592         del_timer(&device_timer);
 593         local_irq_enable();
 594
 595         req = CURRENT;
 596         if (!req) {
 597                 do_hd = NULL;
 598                 return;
 599         }
 600
 601         if (reset) {
 602                 local_irq_disable();
 603                 reset_hd();
 604                 return;
 605         }
 606         disk = req->rq_disk->private_data;
 607         block = req->sector;
 608         nsect = req->nr_sectors;
 609         if (block >= get_capacity(req->rq_disk) ||
 610             ((block+nsect) > get_capacity(req->rq_disk))) {
 611                 printk("%s: bad access: block=%d, count=%d\n",
 612                         req->rq_disk->disk_name, block, nsect);
 613                 end_request(req, 0);
 614                 goto repeat;
 615         }
 616
 617         if (disk->special_op) {
 618                 if (do_special_op(disk, req))
 619                         goto repeat;
 620                 return;
 621         }
 622         sec   = block % disk->sect + 1;
 623         track = block / disk->sect;
 624         head  = track % disk->head;
 625         cyl   = track / disk->head;
 626 #ifdef DEBUG
 627         printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
 628                 req->rq_disk->disk_name,
 629                 req_data_dir(req) == READ ? "read" : "writ",
 630                 cyl, head, sec, nsect, req->buffer);
 631 #endif
 632         if (blk_fs_request(req)) {
 633                 switch (rq_data_dir(req)) {
 634                 case READ:
 635                         hd_out(disk, nsect, sec, head, cyl, WIN_READ,
 636                                 &read_intr);
 637                         if (reset)
 638                                 goto repeat;
 639                         break;
 640                 case WRITE:
 641                         hd_out(disk, nsect, sec, head, cyl, WIN_WRITE,
 642                                 &write_intr);
 643                         if (reset)
 644                                 goto repeat;
 645                         if (wait_DRQ()) {
 646                                 bad_rw_intr();
 647                                 goto repeat;
 648                         }
 649                         outsw(HD_DATA, req->buffer, 256);
 650                         break;
 651                 default:
 652                         printk("unknown hd-command\n");
 653                         end_request(req, 0);
 654                         break;
 655                 }
 656         }
 657 }
 658
 659 static void do_hd_request(struct request_queue *q)
 660 {
 661         disable_irq(HD_IRQ);
 662         hd_request();
 663         enable_irq(HD_IRQ);
 664 }
 665
 666 static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 667 {
 668         struct hd_i_struct *disk = bdev->bd_disk->private_data;
 669
 670         geo->heads = disk->head;
 671         geo->sectors = disk->sect;
 672         geo->cylinders = disk->cyl;
 673         return 0;
 674 }
 675
 676 /*
 677  * Releasing a block device means we sync() it, so that it can safely
 678  * be forgotten about...
 679  */
 680
 681 static irqreturn_t hd_interrupt(int irq, void *dev_id)
 682 {
 683         void (*handler)(void) = do_hd;
 684
 685         do_hd = NULL;
 686         del_timer(&device_timer);
 687         if (!handler)
 688                 handler = unexpected_hd_interrupt;
 689         handler();
 690         local_irq_enable();
 691         return IRQ_HANDLED;
 692 }
 693
 694 static struct block_device_operations hd_fops = {
 695         .getgeo =       hd_getgeo,
 696 };
 697
 698 /*
 699  * This is the hard disk IRQ description. The IRQF_DISABLED in sa_flags
 700  * means we run the IRQ-handler with interrupts disabled:  this is bad for
 701  * interrupt latency, but anything else has led to problems on some
 702  * machines.
 703  *
 704  * We enable interrupts in some of the routines after making sure it's
 705  * safe.
 706  */
 707
 708 static int __init hd_init(void)
 709 {
 710         int drive;
 711
 712         if (register_blkdev(MAJOR_NR, "hd"))
 713                 return -1;
 714
 715         hd_queue = blk_init_queue(do_hd_request, &hd_lock);
 716         if (!hd_queue) {
 717                 unregister_blkdev(MAJOR_NR, "hd");
 718                 return -ENOMEM;
 719         }
 720
 721         blk_queue_max_sectors(hd_queue, 255);
 722         init_timer(&device_timer);
 723         device_timer.function = hd_times_out;
 724         blk_queue_hardsect_size(hd_queue, 512);
 725
 726         if (!NR_HD) {
 727                 /*
 728                  * We don't know anything about the drive.  This means
 729                  * that you *MUST* specify the drive parameters to the
 730                  * kernel yourself.
 731                  *
 732                  * If we were on an i386, we used to read this info from
 733                  * the BIOS or CMOS.  This doesn't work all that well,
 734                  * since this assumes that this is a primary or secondary
 735                  * drive, and if we're using this legacy driver, it's
 736                  * probably an auxilliary controller added to recover
 737                  * legacy data off an ST-506 drive.  Either way, it's
 738                  * definitely safest to have the user explicitly specify
 739                  * the information.
 740                  */
 741                 printk("hd: no drives specified - use hd=cyl,head,sectors"
 742                         " on kernel command line\n");
 743                 goto out;
 744         }
 745
 746         for (drive = 0 ; drive < NR_HD ; drive++) {
 747                 struct gendisk *disk = alloc_disk(64);
 748                 struct hd_i_struct *p = &hd_info[drive];
 749                 if (!disk)
 750                         goto Enomem;
 751                 disk->major = MAJOR_NR;
 752                 disk->first_minor = drive << 6;
 753                 disk->fops = &hd_fops;
 754                 sprintf(disk->disk_name, "hd%c", 'a'+drive);
 755                 disk->private_data = p;
 756                 set_capacity(disk, p->head * p->sect * p->cyl);
 757                 disk->queue = hd_queue;
 758                 p->unit = drive;
 759                 hd_gendisk[drive] = disk;
 760                 printk("%s: %luMB, CHS=%d/%d/%d\n",
 761                         disk->disk_name, (unsigned long)get_capacity(disk)/2048,
 762                         p->cyl, p->head, p->sect);
 763         }
 764
 765         if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
 766                 printk("hd: unable to get IRQ%d for the hard disk driver\n",
 767                         HD_IRQ);
 768                 goto out1;
 769         }
 770         if (!request_region(HD_DATA, 8, "hd")) {
 771                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
 772                 goto out2;
 773         }
 774         if (!request_region(HD_CMD, 1, "hd(cmd)")) {
 775                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
 776                 goto out3;
 777         }
 778
 779         /* Let them fly */
 780         for (drive = 0; drive < NR_HD; drive++)
 781                 add_disk(hd_gendisk[drive]);
 782
 783         return 0;
 784
 785 out3:
 786         release_region(HD_DATA, 8);
 787 out2:
 788         free_irq(HD_IRQ, NULL);
 789 out1:
 790         for (drive = 0; drive < NR_HD; drive++)
 791                 put_disk(hd_gendisk[drive]);
 792         NR_HD = 0;
 793 out:
 794         del_timer(&device_timer);
 795         unregister_blkdev(MAJOR_NR, "hd");
 796         blk_cleanup_queue(hd_queue);
 797         return -1;
 798 Enomem:
 799         while (drive--)
 800                 put_disk(hd_gendisk[drive]);
 801         goto out;
 802 }
 803
 804 static int __init parse_hd_setup(char *line)
 805 {
 806         int ints[6];
 807
 808         (void) get_options(line, ARRAY_SIZE(ints), ints);
 809         hd_setup(NULL, ints);
 810
 811         return 1;
 812 }
 813 __setup("hd=", parse_hd_setup);
 814
 815 module_init(hd_init);