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