drivers/block/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/init.h>
  41 #include <linux/blkpg.h>
  42 #include <linux/ata.h>
  43 #include <linux/hdreg.h>
  44
  45 #define HD_IRQ 14
  46
  47 #define REALLY_SLOW_IO
  48 #include <asm/system.h>
  49 #include <asm/io.h>
  50 #include <asm/uaccess.h>
  51
  52 #ifdef __arm__
  53 #undef  HD_IRQ
  54 #endif
  55 #include <asm/irq.h>
  56 #ifdef __arm__
  57 #define HD_IRQ IRQ_HARDDISK
  58 #endif
  59
  60 /* Hd controller regster ports */
  61
  62 #define HD_DATA         0x1f0           /* _CTL when writing */
  63 #define HD_ERROR        0x1f1           /* see err-bits */
  64 #define HD_NSECTOR      0x1f2           /* nr of sectors to read/write */
  65 #define HD_SECTOR       0x1f3           /* starting sector */
  66 #define HD_LCYL         0x1f4           /* starting cylinder */
  67 #define HD_HCYL         0x1f5           /* high byte of starting cyl */
  68 #define HD_CURRENT      0x1f6           /* 101dhhhh , d=drive, hhhh=head */
  69 #define HD_STATUS       0x1f7           /* see status-bits */
  70 #define HD_FEATURE      HD_ERROR        /* same io address, read=error, write=feature */
  71 #define HD_PRECOMP      HD_FEATURE      /* obsolete use of this port - predates IDE */
  72 #define HD_COMMAND      HD_STATUS       /* same io address, read=status, write=cmd */
  73
  74 #define HD_CMD          0x3f6           /* used for resets */
  75 #define HD_ALTSTATUS    0x3f6           /* same as HD_STATUS but doesn't clear irq */
  76
  77 /* Bits of HD_STATUS */
  78 #define ERR_STAT                0x01
  79 #define INDEX_STAT              0x02
  80 #define ECC_STAT                0x04    /* Corrected error */
  81 #define DRQ_STAT                0x08
  82 #define SEEK_STAT               0x10
  83 #define SERVICE_STAT            SEEK_STAT
  84 #define WRERR_STAT              0x20
  85 #define READY_STAT              0x40
  86 #define BUSY_STAT               0x80
  87
  88 /* Bits for HD_ERROR */
  89 #define MARK_ERR                0x01    /* Bad address mark */
  90 #define TRK0_ERR                0x02    /* couldn't find track 0 */
  91 #define ABRT_ERR                0x04    /* Command aborted */
  92 #define MCR_ERR                 0x08    /* media change request */
  93 #define ID_ERR                  0x10    /* ID field not found */
  94 #define MC_ERR                  0x20    /* media changed */
  95 #define ECC_ERR                 0x40    /* Uncorrectable ECC error */
  96 #define BBD_ERR                 0x80    /* pre-EIDE meaning:  block marked bad */
  97 #define ICRC_ERR                0x80    /* new meaning:  CRC error during transfer */
  98
  99 static DEFINE_SPINLOCK(hd_lock);
 100 static struct request_queue *hd_queue;
 101 static struct request *hd_req;
 102
 103 #define MAJOR_NR HD_MAJOR
 104
 105 #define TIMEOUT_VALUE   (6*HZ)
 106 #define HD_DELAY        0
 107
 108 #define MAX_ERRORS     16       /* Max read/write errors/sector */
 109 #define RESET_FREQ      8       /* Reset controller every 8th retry */
 110 #define RECAL_FREQ      4       /* Recalibrate every 4th retry */
 111 #define MAX_HD          2
 112
 113 #define STAT_OK         (READY_STAT|SEEK_STAT)
 114 #define OK_STATUS(s)    (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
 115
 116 static void recal_intr(void);
 117 static void bad_rw_intr(void);
 118
 119 static int reset;
 120 static int hd_error;
 121
 122 /*
 123  *  This struct defines the HD's and their types.
 124  */
 125 struct hd_i_struct {
 126         unsigned int head, sect, cyl, wpcom, lzone, ctl;
 127         int unit;
 128         int recalibrate;
 129         int special_op;
 130 };
 131
 132 #ifdef HD_TYPE
 133 static struct hd_i_struct hd_info[] = { HD_TYPE };
 134 static int NR_HD = ARRAY_SIZE(hd_info);
 135 #else
 136 static struct hd_i_struct hd_info[MAX_HD];
 137 static int NR_HD;
 138 #endif
 139
 140 static struct gendisk *hd_gendisk[MAX_HD];
 141
 142 static struct timer_list device_timer;
 143
 144 #define TIMEOUT_VALUE (6*HZ)
 145
 146 #define SET_TIMER                                                       \
 147         do {                                                            \
 148                 mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);      \
 149         } while (0)
 150
 151 static void (*do_hd)(void) = NULL;
 152 #define SET_HANDLER(x) \
 153 if ((do_hd = (x)) != NULL) \
 154         SET_TIMER; \
 155 else \
 156         del_timer(&device_timer);
 157
 158
 159 #if (HD_DELAY > 0)
 160
 161 #include <asm/i8253.h>
 162
 163 unsigned long last_req;
 164
 165 unsigned long read_timer(void)
 166 {
 167         unsigned long t, flags;
 168         int i;
 169
 170         spin_lock_irqsave(&i8253_lock, flags);
 171         t = jiffies * 11932;
 172         outb_p(0, 0x43);
 173         i = inb_p(0x40);
 174         i |= inb(0x40) << 8;
 175         spin_unlock_irqrestore(&i8253_lock, flags);
 176         return(t - i);
 177 }
 178 #endif
 179
 180 static void __init hd_setup(char *str, int *ints)
 181 {
 182         int hdind = 0;
 183
 184         if (ints[0] != 3)
 185                 return;
 186         if (hd_info[0].head != 0)
 187                 hdind = 1;
 188         hd_info[hdind].head = ints[2];
 189         hd_info[hdind].sect = ints[3];
 190         hd_info[hdind].cyl = ints[1];
 191         hd_info[hdind].wpcom = 0;
 192         hd_info[hdind].lzone = ints[1];
 193         hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
 194         NR_HD = hdind+1;
 195 }
 196
 197 static bool hd_end_request(int err, unsigned int bytes)
 198 {
 199         if (__blk_end_request(hd_req, err, bytes))
 200                 return true;
 201         hd_req = NULL;
 202         return false;
 203 }
 204
 205 static bool hd_end_request_cur(int err)
 206 {
 207         return hd_end_request(err, blk_rq_cur_bytes(hd_req));
 208 }
 209
 210 static void dump_status(const char *msg, unsigned int stat)
 211 {
 212         char *name = "hd?";
 213         if (hd_req)
 214                 name = hd_req->rq_disk->disk_name;
 215
 216 #ifdef VERBOSE_ERRORS
 217         printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
 218         if (stat & BUSY_STAT)   printk("Busy ");
 219         if (stat & READY_STAT)  printk("DriveReady ");
 220         if (stat & WRERR_STAT)  printk("WriteFault ");
 221         if (stat & SEEK_STAT)   printk("SeekComplete ");
 222         if (stat & DRQ_STAT)    printk("DataRequest ");
 223         if (stat & ECC_STAT)    printk("CorrectedError ");
 224         if (stat & INDEX_STAT)  printk("Index ");
 225         if (stat & ERR_STAT)    printk("Error ");
 226         printk("}\n");
 227         if ((stat & ERR_STAT) == 0) {
 228                 hd_error = 0;
 229         } else {
 230                 hd_error = inb(HD_ERROR);
 231                 printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
 232                 if (hd_error & BBD_ERR)         printk("BadSector ");
 233                 if (hd_error & ECC_ERR)         printk("UncorrectableError ");
 234                 if (hd_error & ID_ERR)          printk("SectorIdNotFound ");
 235                 if (hd_error & ABRT_ERR)        printk("DriveStatusError ");
 236                 if (hd_error & TRK0_ERR)        printk("TrackZeroNotFound ");
 237                 if (hd_error & MARK_ERR)        printk("AddrMarkNotFound ");
 238                 printk("}");
 239                 if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
 240                         printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
 241                                 inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
 242                         if (hd_req)
 243                                 printk(", sector=%ld", blk_rq_pos(hd_req));
 244                 }
 245                 printk("\n");
 246         }
 247 #else
 248         printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
 249         if ((stat & ERR_STAT) == 0) {
 250                 hd_error = 0;
 251         } else {
 252                 hd_error = inb(HD_ERROR);
 253                 printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
 254         }
 255 #endif
 256 }
 257
 258 static void check_status(void)
 259 {
 260         int i = inb_p(HD_STATUS);
 261
 262         if (!OK_STATUS(i)) {
 263                 dump_status("check_status", i);
 264                 bad_rw_intr();
 265         }
 266 }
 267
 268 static int controller_busy(void)
 269 {
 270         int retries = 100000;
 271         unsigned char status;
 272
 273         do {
 274                 status = inb_p(HD_STATUS);
 275         } while ((status & BUSY_STAT) && --retries);
 276         return status;
 277 }
 278
 279 static int status_ok(void)
 280 {
 281         unsigned char status = inb_p(HD_STATUS);
 282
 283         if (status & BUSY_STAT)
 284                 return 1;       /* Ancient, but does it make sense??? */
 285         if (status & WRERR_STAT)
 286                 return 0;
 287         if (!(status & READY_STAT))
 288                 return 0;
 289         if (!(status & SEEK_STAT))
 290                 return 0;
 291         return 1;
 292 }
 293
 294 static int controller_ready(unsigned int drive, unsigned int head)
 295 {
 296         int retry = 100;
 297
 298         do {
 299                 if (controller_busy() & BUSY_STAT)
 300                         return 0;
 301                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 302                 if (status_ok())
 303                         return 1;
 304         } while (--retry);
 305         return 0;
 306 }
 307
 308 static void hd_out(struct hd_i_struct *disk,
 309                    unsigned int nsect,
 310                    unsigned int sect,
 311                    unsigned int head,
 312                    unsigned int cyl,
 313                    unsigned int cmd,
 314                    void (*intr_addr)(void))
 315 {
 316         unsigned short port;
 317
 318 #if (HD_DELAY > 0)
 319         while (read_timer() - last_req < HD_DELAY)
 320                 /* nothing */;
 321 #endif
 322         if (reset)
 323                 return;
 324         if (!controller_ready(disk->unit, head)) {
 325                 reset = 1;
 326                 return;
 327         }
 328         SET_HANDLER(intr_addr);
 329         outb_p(disk->ctl, HD_CMD);
 330         port = HD_DATA;
 331         outb_p(disk->wpcom >> 2, ++port);
 332         outb_p(nsect, ++port);
 333         outb_p(sect, ++port);
 334         outb_p(cyl, ++port);
 335         outb_p(cyl >> 8, ++port);
 336         outb_p(0xA0 | (disk->unit << 4) | head, ++port);
 337         outb_p(cmd, ++port);
 338 }
 339
 340 static void hd_request (void);
 341
 342 static int drive_busy(void)
 343 {
 344         unsigned int i;
 345         unsigned char c;
 346
 347         for (i = 0; i < 500000 ; i++) {
 348                 c = inb_p(HD_STATUS);
 349                 if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
 350                         return 0;
 351         }
 352         dump_status("reset timed out", c);
 353         return 1;
 354 }
 355
 356 static void reset_controller(void)
 357 {
 358         int     i;
 359
 360         outb_p(4, HD_CMD);
 361         for (i = 0; i < 1000; i++) barrier();
 362         outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
 363         for (i = 0; i < 1000; i++) barrier();
 364         if (drive_busy())
 365                 printk("hd: controller still busy\n");
 366         else if ((hd_error = inb(HD_ERROR)) != 1)
 367                 printk("hd: controller reset failed: %02x\n", hd_error);
 368 }
 369
 370 static void reset_hd(void)
 371 {
 372         static int i;
 373
 374 repeat:
 375         if (reset) {
 376                 reset = 0;
 377                 i = -1;
 378                 reset_controller();
 379         } else {
 380                 check_status();
 381                 if (reset)
 382                         goto repeat;
 383         }
 384         if (++i < NR_HD) {
 385                 struct hd_i_struct *disk = &hd_info[i];
 386                 disk->special_op = disk->recalibrate = 1;
 387                 hd_out(disk, disk->sect, disk->sect, disk->head-1,
 388                         disk->cyl, ATA_CMD_INIT_DEV_PARAMS, &reset_hd);
 389                 if (reset)
 390                         goto repeat;
 391         } else
 392                 hd_request();
 393 }
 394
 395 /*
 396  * Ok, don't know what to do with the unexpected interrupts: on some machines
 397  * doing a reset and a retry seems to result in an eternal loop. Right now I
 398  * ignore it, and just set the timeout.
 399  *
 400  * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 401  * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 402  * "good", we just ignore the interrupt completely.
 403  */
 404 static void unexpected_hd_interrupt(void)
 405 {
 406         unsigned int stat = inb_p(HD_STATUS);
 407
 408         if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
 409                 dump_status("unexpected interrupt", stat);
 410                 SET_TIMER;
 411         }
 412 }
 413
 414 /*
 415  * bad_rw_intr() now tries to be a bit smarter and does things
 416  * according to the error returned by the controller.
 417  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 418  */
 419 static void bad_rw_intr(void)
 420 {
 421         struct request *req = hd_req;
 422
 423         if (req != NULL) {
 424                 struct hd_i_struct *disk = req->rq_disk->private_data;
 425                 if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 426                         hd_end_request_cur(-EIO);
 427                         disk->special_op = disk->recalibrate = 1;
 428                 } else if (req->errors % RESET_FREQ == 0)
 429                         reset = 1;
 430                 else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
 431                         disk->special_op = disk->recalibrate = 1;
 432                 /* Otherwise just retry */
 433         }
 434 }
 435
 436 static inline int wait_DRQ(void)
 437 {
 438         int retries;
 439         int stat;
 440
 441         for (retries = 0; retries < 100000; retries++) {
 442                 stat = inb_p(HD_STATUS);
 443                 if (stat & DRQ_STAT)
 444                         return 0;
 445         }
 446         dump_status("wait_DRQ", stat);
 447         return -1;
 448 }
 449
 450 static void read_intr(void)
 451 {
 452         struct request *req;
 453         int i, retries = 100000;
 454
 455         do {
 456                 i = (unsigned) inb_p(HD_STATUS);
 457                 if (i & BUSY_STAT)
 458                         continue;
 459                 if (!OK_STATUS(i))
 460                         break;
 461                 if (i & DRQ_STAT)
 462                         goto ok_to_read;
 463         } while (--retries > 0);
 464         dump_status("read_intr", i);
 465         bad_rw_intr();
 466         hd_request();
 467         return;
 468
 469 ok_to_read:
 470         req = hd_req;
 471         insw(HD_DATA, req->buffer, 256);
 472 #ifdef DEBUG
 473         printk("%s: read: sector %ld, remaining = %u, buffer=%p\n",
 474                req->rq_disk->disk_name, blk_rq_pos(req) + 1,
 475                blk_rq_sectors(req) - 1, req->buffer+512);
 476 #endif
 477         if (hd_end_request(0, 512)) {
 478                 SET_HANDLER(&read_intr);
 479                 return;
 480         }
 481
 482         (void) inb_p(HD_STATUS);
 483 #if (HD_DELAY > 0)
 484         last_req = read_timer();
 485 #endif
 486         hd_request();
 487 }
 488
 489 static void write_intr(void)
 490 {
 491         struct request *req = hd_req;
 492         int i;
 493         int retries = 100000;
 494
 495         do {
 496                 i = (unsigned) inb_p(HD_STATUS);
 497                 if (i & BUSY_STAT)
 498                         continue;
 499                 if (!OK_STATUS(i))
 500                         break;
 501                 if ((blk_rq_sectors(req) <= 1) || (i & DRQ_STAT))
 502                         goto ok_to_write;
 503         } while (--retries > 0);
 504         dump_status("write_intr", i);
 505         bad_rw_intr();
 506         hd_request();
 507         return;
 508
 509 ok_to_write:
 510         if (hd_end_request(0, 512)) {
 511                 SET_HANDLER(&write_intr);
 512                 outsw(HD_DATA, req->buffer, 256);
 513                 return;
 514         }
 515
 516 #if (HD_DELAY > 0)
 517         last_req = read_timer();
 518 #endif
 519         hd_request();
 520 }
 521
 522 static void recal_intr(void)
 523 {
 524         check_status();
 525 #if (HD_DELAY > 0)
 526         last_req = read_timer();
 527 #endif
 528         hd_request();
 529 }
 530
 531 /*
 532  * This is another of the error-routines I don't know what to do with. The
 533  * best idea seems to just set reset, and start all over again.
 534  */
 535 static void hd_times_out(unsigned long dummy)
 536 {
 537         char *name;
 538
 539         do_hd = NULL;
 540
 541         if (!hd_req)
 542                 return;
 543
 544         spin_lock_irq(hd_queue->queue_lock);
 545         reset = 1;
 546         name = hd_req->rq_disk->disk_name;
 547         printk("%s: timeout\n", name);
 548         if (++hd_req->errors >= MAX_ERRORS) {
 549 #ifdef DEBUG
 550                 printk("%s: too many errors\n", name);
 551 #endif
 552                 hd_end_request_cur(-EIO);
 553         }
 554         hd_request();
 555         spin_unlock_irq(hd_queue->queue_lock);
 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, ATA_CMD_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                 hd_end_request_cur(-EIO);
 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
 594         if (!hd_req) {
 595                 hd_req = elv_next_request(hd_queue);
 596                 if (!hd_req) {
 597                         do_hd = NULL;
 598                         return;
 599                 }
 600                 blkdev_dequeue_request(hd_req);
 601         }
 602         req = hd_req;
 603
 604         if (reset) {
 605                 reset_hd();
 606                 return;
 607         }
 608         disk = req->rq_disk->private_data;
 609         block = blk_rq_pos(req);
 610         nsect = blk_rq_sectors(req);
 611         if (block >= get_capacity(req->rq_disk) ||
 612             ((block+nsect) > get_capacity(req->rq_disk))) {
 613                 printk("%s: bad access: block=%d, count=%d\n",
 614                         req->rq_disk->disk_name, block, nsect);
 615                 hd_end_request_cur(-EIO);
 616                 goto repeat;
 617         }
 618
 619         if (disk->special_op) {
 620                 if (do_special_op(disk, req))
 621                         goto repeat;
 622                 return;
 623         }
 624         sec   = block % disk->sect + 1;
 625         track = block / disk->sect;
 626         head  = track % disk->head;
 627         cyl   = track / disk->head;
 628 #ifdef DEBUG
 629         printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
 630                 req->rq_disk->disk_name,
 631                 req_data_dir(req) == READ ? "read" : "writ",
 632                 cyl, head, sec, nsect, req->buffer);
 633 #endif
 634         if (blk_fs_request(req)) {
 635                 switch (rq_data_dir(req)) {
 636                 case READ:
 637                         hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_READ,
 638                                 &read_intr);
 639                         if (reset)
 640                                 goto repeat;
 641                         break;
 642                 case WRITE:
 643                         hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_WRITE,
 644                                 &write_intr);
 645                         if (reset)
 646                                 goto repeat;
 647                         if (wait_DRQ()) {
 648                                 bad_rw_intr();
 649                                 goto repeat;
 650                         }
 651                         outsw(HD_DATA, req->buffer, 256);
 652                         break;
 653                 default:
 654                         printk("unknown hd-command\n");
 655                         hd_end_request_cur(-EIO);
 656                         break;
 657                 }
 658         }
 659 }
 660
 661 static void do_hd_request(struct request_queue *q)
 662 {
 663         hd_request();
 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         spin_lock(hd_queue->queue_lock);
 686
 687         do_hd = NULL;
 688         del_timer(&device_timer);
 689         if (!handler)
 690                 handler = unexpected_hd_interrupt;
 691         handler();
 692
 693         spin_unlock(hd_queue->queue_lock);
 694
 695         return IRQ_HANDLED;
 696 }
 697
 698 static struct block_device_operations hd_fops = {
 699         .getgeo =       hd_getgeo,
 700 };
 701
 702 /*
 703  * This is the hard disk IRQ description. The IRQF_DISABLED in sa_flags
 704  * means we run the IRQ-handler with interrupts disabled:  this is bad for
 705  * interrupt latency, but anything else has led to problems on some
 706  * machines.
 707  *
 708  * We enable interrupts in some of the routines after making sure it's
 709  * safe.
 710  */
 711
 712 static int __init hd_init(void)
 713 {
 714         int drive;
 715
 716         if (register_blkdev(MAJOR_NR, "hd"))
 717                 return -1;
 718
 719         hd_queue = blk_init_queue(do_hd_request, &hd_lock);
 720         if (!hd_queue) {
 721                 unregister_blkdev(MAJOR_NR, "hd");
 722                 return -ENOMEM;
 723         }
 724
 725         blk_queue_max_sectors(hd_queue, 255);
 726         init_timer(&device_timer);
 727         device_timer.function = hd_times_out;
 728         blk_queue_hardsect_size(hd_queue, 512);
 729
 730         if (!NR_HD) {
 731                 /*
 732                  * We don't know anything about the drive.  This means
 733                  * that you *MUST* specify the drive parameters to the
 734                  * kernel yourself.
 735                  *
 736                  * If we were on an i386, we used to read this info from
 737                  * the BIOS or CMOS.  This doesn't work all that well,
 738                  * since this assumes that this is a primary or secondary
 739                  * drive, and if we're using this legacy driver, it's
 740                  * probably an auxilliary controller added to recover
 741                  * legacy data off an ST-506 drive.  Either way, it's
 742                  * definitely safest to have the user explicitly specify
 743                  * the information.
 744                  */
 745                 printk("hd: no drives specified - use hd=cyl,head,sectors"
 746                         " on kernel command line\n");
 747                 goto out;
 748         }
 749
 750         for (drive = 0 ; drive < NR_HD ; drive++) {
 751                 struct gendisk *disk = alloc_disk(64);
 752                 struct hd_i_struct *p = &hd_info[drive];
 753                 if (!disk)
 754                         goto Enomem;
 755                 disk->major = MAJOR_NR;
 756                 disk->first_minor = drive << 6;
 757                 disk->fops = &hd_fops;
 758                 sprintf(disk->disk_name, "hd%c", 'a'+drive);
 759                 disk->private_data = p;
 760                 set_capacity(disk, p->head * p->sect * p->cyl);
 761                 disk->queue = hd_queue;
 762                 p->unit = drive;
 763                 hd_gendisk[drive] = disk;
 764                 printk("%s: %luMB, CHS=%d/%d/%d\n",
 765                         disk->disk_name, (unsigned long)get_capacity(disk)/2048,
 766                         p->cyl, p->head, p->sect);
 767         }
 768
 769         if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
 770                 printk("hd: unable to get IRQ%d for the hard disk driver\n",
 771                         HD_IRQ);
 772                 goto out1;
 773         }
 774         if (!request_region(HD_DATA, 8, "hd")) {
 775                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
 776                 goto out2;
 777         }
 778         if (!request_region(HD_CMD, 1, "hd(cmd)")) {
 779                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
 780                 goto out3;
 781         }
 782
 783         /* Let them fly */
 784         for (drive = 0; drive < NR_HD; drive++)
 785                 add_disk(hd_gendisk[drive]);
 786
 787         return 0;
 788
 789 out3:
 790         release_region(HD_DATA, 8);
 791 out2:
 792         free_irq(HD_IRQ, NULL);
 793 out1:
 794         for (drive = 0; drive < NR_HD; drive++)
 795                 put_disk(hd_gendisk[drive]);
 796         NR_HD = 0;
 797 out:
 798         del_timer(&device_timer);
 799         unregister_blkdev(MAJOR_NR, "hd");
 800         blk_cleanup_queue(hd_queue);
 801         return -1;
 802 Enomem:
 803         while (drive--)
 804                 put_disk(hd_gendisk[drive]);
 805         goto out;
 806 }
 807
 808 static int __init parse_hd_setup(char *line)
 809 {
 810         int ints[6];
 811
 812         (void) get_options(line, ARRAY_SIZE(ints), ints);
 813         hd_setup(NULL, ints);
 814
 815         return 1;
 816 }
 817 __setup("hd=", parse_hd_setup);
 818
 819 late_initcall(hd_init);