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 TIMEOUT_VALUE   (6*HZ)
 104 #define HD_DELAY        0
 105
 106 #define MAX_ERRORS     16       /* Max read/write errors/sector */
 107 #define RESET_FREQ      8       /* Reset controller every 8th retry */
 108 #define RECAL_FREQ      4       /* Recalibrate every 4th retry */
 109 #define MAX_HD          2
 110
 111 #define STAT_OK         (READY_STAT|SEEK_STAT)
 112 #define OK_STATUS(s)    (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
 113
 114 static void recal_intr(void);
 115 static void bad_rw_intr(void);
 116
 117 static int reset;
 118 static int hd_error;
 119
 120 /*
 121  *  This struct defines the HD's and their types.
 122  */
 123 struct hd_i_struct {
 124         unsigned int head, sect, cyl, wpcom, lzone, ctl;
 125         int unit;
 126         int recalibrate;
 127         int special_op;
 128 };
 129
 130 #ifdef HD_TYPE
 131 static struct hd_i_struct hd_info[] = { HD_TYPE };
 132 static int NR_HD = ARRAY_SIZE(hd_info);
 133 #else
 134 static struct hd_i_struct hd_info[MAX_HD];
 135 static int NR_HD;
 136 #endif
 137
 138 static struct gendisk *hd_gendisk[MAX_HD];
 139
 140 static struct timer_list device_timer;
 141
 142 #define TIMEOUT_VALUE (6*HZ)
 143
 144 #define SET_TIMER                                                       \
 145         do {                                                            \
 146                 mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);      \
 147         } while (0)
 148
 149 static void (*do_hd)(void) = NULL;
 150 #define SET_HANDLER(x) \
 151 if ((do_hd = (x)) != NULL) \
 152         SET_TIMER; \
 153 else \
 154         del_timer(&device_timer);
 155
 156
 157 #if (HD_DELAY > 0)
 158
 159 #include <asm/i8253.h>
 160
 161 unsigned long last_req;
 162
 163 unsigned long read_timer(void)
 164 {
 165         unsigned long t, flags;
 166         int i;
 167
 168         spin_lock_irqsave(&i8253_lock, flags);
 169         t = jiffies * 11932;
 170         outb_p(0, 0x43);
 171         i = inb_p(0x40);
 172         i |= inb(0x40) << 8;
 173         spin_unlock_irqrestore(&i8253_lock, flags);
 174         return(t - i);
 175 }
 176 #endif
 177
 178 static void __init hd_setup(char *str, int *ints)
 179 {
 180         int hdind = 0;
 181
 182         if (ints[0] != 3)
 183                 return;
 184         if (hd_info[0].head != 0)
 185                 hdind = 1;
 186         hd_info[hdind].head = ints[2];
 187         hd_info[hdind].sect = ints[3];
 188         hd_info[hdind].cyl = ints[1];
 189         hd_info[hdind].wpcom = 0;
 190         hd_info[hdind].lzone = ints[1];
 191         hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
 192         NR_HD = hdind+1;
 193 }
 194
 195 static bool hd_end_request(int err, unsigned int bytes)
 196 {
 197         if (__blk_end_request(hd_req, err, bytes))
 198                 return true;
 199         hd_req = NULL;
 200         return false;
 201 }
 202
 203 static bool hd_end_request_cur(int err)
 204 {
 205         return hd_end_request(err, blk_rq_cur_bytes(hd_req));
 206 }
 207
 208 static void dump_status(const char *msg, unsigned int stat)
 209 {
 210         char *name = "hd?";
 211         if (hd_req)
 212                 name = hd_req->rq_disk->disk_name;
 213
 214 #ifdef VERBOSE_ERRORS
 215         printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
 216         if (stat & BUSY_STAT)   printk("Busy ");
 217         if (stat & READY_STAT)  printk("DriveReady ");
 218         if (stat & WRERR_STAT)  printk("WriteFault ");
 219         if (stat & SEEK_STAT)   printk("SeekComplete ");
 220         if (stat & DRQ_STAT)    printk("DataRequest ");
 221         if (stat & ECC_STAT)    printk("CorrectedError ");
 222         if (stat & INDEX_STAT)  printk("Index ");
 223         if (stat & ERR_STAT)    printk("Error ");
 224         printk("}\n");
 225         if ((stat & ERR_STAT) == 0) {
 226                 hd_error = 0;
 227         } else {
 228                 hd_error = inb(HD_ERROR);
 229                 printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
 230                 if (hd_error & BBD_ERR)         printk("BadSector ");
 231                 if (hd_error & ECC_ERR)         printk("UncorrectableError ");
 232                 if (hd_error & ID_ERR)          printk("SectorIdNotFound ");
 233                 if (hd_error & ABRT_ERR)        printk("DriveStatusError ");
 234                 if (hd_error & TRK0_ERR)        printk("TrackZeroNotFound ");
 235                 if (hd_error & MARK_ERR)        printk("AddrMarkNotFound ");
 236                 printk("}");
 237                 if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
 238                         printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
 239                                 inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
 240                         if (hd_req)
 241                                 printk(", sector=%ld", blk_rq_pos(hd_req));
 242                 }
 243                 printk("\n");
 244         }
 245 #else
 246         printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
 247         if ((stat & ERR_STAT) == 0) {
 248                 hd_error = 0;
 249         } else {
 250                 hd_error = inb(HD_ERROR);
 251                 printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
 252         }
 253 #endif
 254 }
 255
 256 static void check_status(void)
 257 {
 258         int i = inb_p(HD_STATUS);
 259
 260         if (!OK_STATUS(i)) {
 261                 dump_status("check_status", i);
 262                 bad_rw_intr();
 263         }
 264 }
 265
 266 static int controller_busy(void)
 267 {
 268         int retries = 100000;
 269         unsigned char status;
 270
 271         do {
 272                 status = inb_p(HD_STATUS);
 273         } while ((status & BUSY_STAT) && --retries);
 274         return status;
 275 }
 276
 277 static int status_ok(void)
 278 {
 279         unsigned char status = inb_p(HD_STATUS);
 280
 281         if (status & BUSY_STAT)
 282                 return 1;       /* Ancient, but does it make sense??? */
 283         if (status & WRERR_STAT)
 284                 return 0;
 285         if (!(status & READY_STAT))
 286                 return 0;
 287         if (!(status & SEEK_STAT))
 288                 return 0;
 289         return 1;
 290 }
 291
 292 static int controller_ready(unsigned int drive, unsigned int head)
 293 {
 294         int retry = 100;
 295
 296         do {
 297                 if (controller_busy() & BUSY_STAT)
 298                         return 0;
 299                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 300                 if (status_ok())
 301                         return 1;
 302         } while (--retry);
 303         return 0;
 304 }
 305
 306 static void hd_out(struct hd_i_struct *disk,
 307                    unsigned int nsect,
 308                    unsigned int sect,
 309                    unsigned int head,
 310                    unsigned int cyl,
 311                    unsigned int cmd,
 312                    void (*intr_addr)(void))
 313 {
 314         unsigned short port;
 315
 316 #if (HD_DELAY > 0)
 317         while (read_timer() - last_req < HD_DELAY)
 318                 /* nothing */;
 319 #endif
 320         if (reset)
 321                 return;
 322         if (!controller_ready(disk->unit, head)) {
 323                 reset = 1;
 324                 return;
 325         }
 326         SET_HANDLER(intr_addr);
 327         outb_p(disk->ctl, HD_CMD);
 328         port = HD_DATA;
 329         outb_p(disk->wpcom >> 2, ++port);
 330         outb_p(nsect, ++port);
 331         outb_p(sect, ++port);
 332         outb_p(cyl, ++port);
 333         outb_p(cyl >> 8, ++port);
 334         outb_p(0xA0 | (disk->unit << 4) | head, ++port);
 335         outb_p(cmd, ++port);
 336 }
 337
 338 static void hd_request (void);
 339
 340 static int drive_busy(void)
 341 {
 342         unsigned int i;
 343         unsigned char c;
 344
 345         for (i = 0; i < 500000 ; i++) {
 346                 c = inb_p(HD_STATUS);
 347                 if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
 348                         return 0;
 349         }
 350         dump_status("reset timed out", c);
 351         return 1;
 352 }
 353
 354 static void reset_controller(void)
 355 {
 356         int     i;
 357
 358         outb_p(4, HD_CMD);
 359         for (i = 0; i < 1000; i++) barrier();
 360         outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
 361         for (i = 0; i < 1000; i++) barrier();
 362         if (drive_busy())
 363                 printk("hd: controller still busy\n");
 364         else if ((hd_error = inb(HD_ERROR)) != 1)
 365                 printk("hd: controller reset failed: %02x\n", hd_error);
 366 }
 367
 368 static void reset_hd(void)
 369 {
 370         static int i;
 371
 372 repeat:
 373         if (reset) {
 374                 reset = 0;
 375                 i = -1;
 376                 reset_controller();
 377         } else {
 378                 check_status();
 379                 if (reset)
 380                         goto repeat;
 381         }
 382         if (++i < NR_HD) {
 383                 struct hd_i_struct *disk = &hd_info[i];
 384                 disk->special_op = disk->recalibrate = 1;
 385                 hd_out(disk, disk->sect, disk->sect, disk->head-1,
 386                         disk->cyl, ATA_CMD_INIT_DEV_PARAMS, &reset_hd);
 387                 if (reset)
 388                         goto repeat;
 389         } else
 390                 hd_request();
 391 }
 392
 393 /*
 394  * Ok, don't know what to do with the unexpected interrupts: on some machines
 395  * doing a reset and a retry seems to result in an eternal loop. Right now I
 396  * ignore it, and just set the timeout.
 397  *
 398  * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 399  * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 400  * "good", we just ignore the interrupt completely.
 401  */
 402 static void unexpected_hd_interrupt(void)
 403 {
 404         unsigned int stat = inb_p(HD_STATUS);
 405
 406         if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
 407                 dump_status("unexpected interrupt", stat);
 408                 SET_TIMER;
 409         }
 410 }
 411
 412 /*
 413  * bad_rw_intr() now tries to be a bit smarter and does things
 414  * according to the error returned by the controller.
 415  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 416  */
 417 static void bad_rw_intr(void)
 418 {
 419         struct request *req = hd_req;
 420
 421         if (req != NULL) {
 422                 struct hd_i_struct *disk = req->rq_disk->private_data;
 423                 if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 424                         hd_end_request_cur(-EIO);
 425                         disk->special_op = disk->recalibrate = 1;
 426                 } else if (req->errors % RESET_FREQ == 0)
 427                         reset = 1;
 428                 else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
 429                         disk->special_op = disk->recalibrate = 1;
 430                 /* Otherwise just retry */
 431         }
 432 }
 433
 434 static inline int wait_DRQ(void)
 435 {
 436         int retries;
 437         int stat;
 438
 439         for (retries = 0; retries < 100000; retries++) {
 440                 stat = inb_p(HD_STATUS);
 441                 if (stat & DRQ_STAT)
 442                         return 0;
 443         }
 444         dump_status("wait_DRQ", stat);
 445         return -1;
 446 }
 447
 448 static void read_intr(void)
 449 {
 450         struct request *req;
 451         int i, retries = 100000;
 452
 453         do {
 454                 i = (unsigned) inb_p(HD_STATUS);
 455                 if (i & BUSY_STAT)
 456                         continue;
 457                 if (!OK_STATUS(i))
 458                         break;
 459                 if (i & DRQ_STAT)
 460                         goto ok_to_read;
 461         } while (--retries > 0);
 462         dump_status("read_intr", i);
 463         bad_rw_intr();
 464         hd_request();
 465         return;
 466
 467 ok_to_read:
 468         req = hd_req;
 469         insw(HD_DATA, req->buffer, 256);
 470 #ifdef DEBUG
 471         printk("%s: read: sector %ld, remaining = %u, buffer=%p\n",
 472                req->rq_disk->disk_name, blk_rq_pos(req) + 1,
 473                blk_rq_sectors(req) - 1, req->buffer+512);
 474 #endif
 475         if (hd_end_request(0, 512)) {
 476                 SET_HANDLER(&read_intr);
 477                 return;
 478         }
 479
 480         (void) inb_p(HD_STATUS);
 481 #if (HD_DELAY > 0)
 482         last_req = read_timer();
 483 #endif
 484         hd_request();
 485 }
 486
 487 static void write_intr(void)
 488 {
 489         struct request *req = hd_req;
 490         int i;
 491         int retries = 100000;
 492
 493         do {
 494                 i = (unsigned) inb_p(HD_STATUS);
 495                 if (i & BUSY_STAT)
 496                         continue;
 497                 if (!OK_STATUS(i))
 498                         break;
 499                 if ((blk_rq_sectors(req) <= 1) || (i & DRQ_STAT))
 500                         goto ok_to_write;
 501         } while (--retries > 0);
 502         dump_status("write_intr", i);
 503         bad_rw_intr();
 504         hd_request();
 505         return;
 506
 507 ok_to_write:
 508         if (hd_end_request(0, 512)) {
 509                 SET_HANDLER(&write_intr);
 510                 outsw(HD_DATA, req->buffer, 256);
 511                 return;
 512         }
 513
 514 #if (HD_DELAY > 0)
 515         last_req = read_timer();
 516 #endif
 517         hd_request();
 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 (!hd_req)
 540                 return;
 541
 542         spin_lock_irq(hd_queue->queue_lock);
 543         reset = 1;
 544         name = hd_req->rq_disk->disk_name;
 545         printk("%s: timeout\n", name);
 546         if (++hd_req->errors >= MAX_ERRORS) {
 547 #ifdef DEBUG
 548                 printk("%s: too many errors\n", name);
 549 #endif
 550                 hd_end_request_cur(-EIO);
 551         }
 552         hd_request();
 553         spin_unlock_irq(hd_queue->queue_lock);
 554 }
 555
 556 static int do_special_op(struct hd_i_struct *disk, struct request *req)
 557 {
 558         if (disk->recalibrate) {
 559                 disk->recalibrate = 0;
 560                 hd_out(disk, disk->sect, 0, 0, 0, ATA_CMD_RESTORE, &recal_intr);
 561                 return reset;
 562         }
 563         if (disk->head > 16) {
 564                 printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
 565                 hd_end_request_cur(-EIO);
 566         }
 567         disk->special_op = 0;
 568         return 1;
 569 }
 570
 571 /*
 572  * The driver enables interrupts as much as possible.  In order to do this,
 573  * (a) the device-interrupt is disabled before entering hd_request(),
 574  * and (b) the timeout-interrupt is disabled before the sti().
 575  *
 576  * Interrupts are still masked (by default) whenever we are exchanging
 577  * data/cmds with a drive, because some drives seem to have very poor
 578  * tolerance for latency during I/O. The IDE driver has support to unmask
 579  * interrupts for non-broken hardware, so use that driver if required.
 580  */
 581 static void hd_request(void)
 582 {
 583         unsigned int block, nsect, sec, track, head, cyl;
 584         struct hd_i_struct *disk;
 585         struct request *req;
 586
 587         if (do_hd)
 588                 return;
 589 repeat:
 590         del_timer(&device_timer);
 591
 592         if (!hd_req) {
 593                 hd_req = blk_fetch_request(hd_queue);
 594                 if (!hd_req) {
 595                         do_hd = NULL;
 596                         return;
 597                 }
 598         }
 599         req = hd_req;
 600
 601         if (reset) {
 602                 reset_hd();
 603                 return;
 604         }
 605         disk = req->rq_disk->private_data;
 606         block = blk_rq_pos(req);
 607         nsect = blk_rq_sectors(req);
 608         if (block >= get_capacity(req->rq_disk) ||
 609             ((block+nsect) > get_capacity(req->rq_disk))) {
 610                 printk("%s: bad access: block=%d, count=%d\n",
 611                         req->rq_disk->disk_name, block, nsect);
 612                 hd_end_request_cur(-EIO);
 613                 goto repeat;
 614         }
 615
 616         if (disk->special_op) {
 617                 if (do_special_op(disk, req))
 618                         goto repeat;
 619                 return;
 620         }
 621         sec   = block % disk->sect + 1;
 622         track = block / disk->sect;
 623         head  = track % disk->head;
 624         cyl   = track / disk->head;
 625 #ifdef DEBUG
 626         printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
 627                 req->rq_disk->disk_name,
 628                 req_data_dir(req) == READ ? "read" : "writ",
 629                 cyl, head, sec, nsect, req->buffer);
 630 #endif
 631         if (blk_fs_request(req)) {
 632                 switch (rq_data_dir(req)) {
 633                 case READ:
 634                         hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_READ,
 635                                 &read_intr);
 636                         if (reset)
 637                                 goto repeat;
 638                         break;
 639                 case WRITE:
 640                         hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_WRITE,
 641                                 &write_intr);
 642                         if (reset)
 643                                 goto repeat;
 644                         if (wait_DRQ()) {
 645                                 bad_rw_intr();
 646                                 goto repeat;
 647                         }
 648                         outsw(HD_DATA, req->buffer, 256);
 649                         break;
 650                 default:
 651                         printk("unknown hd-command\n");
 652                         hd_end_request_cur(-EIO);
 653                         break;
 654                 }
 655         }
 656 }
 657
 658 static void do_hd_request(struct request_queue *q)
 659 {
 660         hd_request();
 661 }
 662
 663 static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 664 {
 665         struct hd_i_struct *disk = bdev->bd_disk->private_data;
 666
 667         geo->heads = disk->head;
 668         geo->sectors = disk->sect;
 669         geo->cylinders = disk->cyl;
 670         return 0;
 671 }
 672
 673 /*
 674  * Releasing a block device means we sync() it, so that it can safely
 675  * be forgotten about...
 676  */
 677
 678 static irqreturn_t hd_interrupt(int irq, void *dev_id)
 679 {
 680         void (*handler)(void) = do_hd;
 681
 682         spin_lock(hd_queue->queue_lock);
 683
 684         do_hd = NULL;
 685         del_timer(&device_timer);
 686         if (!handler)
 687                 handler = unexpected_hd_interrupt;
 688         handler();
 689
 690         spin_unlock(hd_queue->queue_lock);
 691
 692         return IRQ_HANDLED;
 693 }
 694
 695 static const struct block_device_operations hd_fops = {
 696         .getgeo =       hd_getgeo,
 697 };
 698
 699 /*
 700  * This is the hard disk IRQ description. The IRQF_DISABLED in sa_flags
 701  * means we run the IRQ-handler with interrupts disabled:  this is bad for
 702  * interrupt latency, but anything else has led to problems on some
 703  * machines.
 704  *
 705  * We enable interrupts in some of the routines after making sure it's
 706  * safe.
 707  */
 708
 709 static int __init hd_init(void)
 710 {
 711         int drive;
 712
 713         if (register_blkdev(HD_MAJOR, "hd"))
 714                 return -1;
 715
 716         hd_queue = blk_init_queue(do_hd_request, &hd_lock);
 717         if (!hd_queue) {
 718                 unregister_blkdev(HD_MAJOR, "hd");
 719                 return -ENOMEM;
 720         }
 721
 722         blk_queue_max_sectors(hd_queue, 255);
 723         init_timer(&device_timer);
 724         device_timer.function = hd_times_out;
 725         blk_queue_logical_block_size(hd_queue, 512);
 726
 727         if (!NR_HD) {
 728                 /*
 729                  * We don't know anything about the drive.  This means
 730                  * that you *MUST* specify the drive parameters to the
 731                  * kernel yourself.
 732                  *
 733                  * If we were on an i386, we used to read this info from
 734                  * the BIOS or CMOS.  This doesn't work all that well,
 735                  * since this assumes that this is a primary or secondary
 736                  * drive, and if we're using this legacy driver, it's
 737                  * probably an auxilliary controller added to recover
 738                  * legacy data off an ST-506 drive.  Either way, it's
 739                  * definitely safest to have the user explicitly specify
 740                  * the information.
 741                  */
 742                 printk("hd: no drives specified - use hd=cyl,head,sectors"
 743                         " on kernel command line\n");
 744                 goto out;
 745         }
 746
 747         for (drive = 0 ; drive < NR_HD ; drive++) {
 748                 struct gendisk *disk = alloc_disk(64);
 749                 struct hd_i_struct *p = &hd_info[drive];
 750                 if (!disk)
 751                         goto Enomem;
 752                 disk->major = HD_MAJOR;
 753                 disk->first_minor = drive << 6;
 754                 disk->fops = &hd_fops;
 755                 sprintf(disk->disk_name, "hd%c", 'a'+drive);
 756                 disk->private_data = p;
 757                 set_capacity(disk, p->head * p->sect * p->cyl);
 758                 disk->queue = hd_queue;
 759                 p->unit = drive;
 760                 hd_gendisk[drive] = disk;
 761                 printk("%s: %luMB, CHS=%d/%d/%d\n",
 762                         disk->disk_name, (unsigned long)get_capacity(disk)/2048,
 763                         p->cyl, p->head, p->sect);
 764         }
 765
 766         if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
 767                 printk("hd: unable to get IRQ%d for the hard disk driver\n",
 768                         HD_IRQ);
 769                 goto out1;
 770         }
 771         if (!request_region(HD_DATA, 8, "hd")) {
 772                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
 773                 goto out2;
 774         }
 775         if (!request_region(HD_CMD, 1, "hd(cmd)")) {
 776                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
 777                 goto out3;
 778         }
 779
 780         /* Let them fly */
 781         for (drive = 0; drive < NR_HD; drive++)
 782                 add_disk(hd_gendisk[drive]);
 783
 784         return 0;
 785
 786 out3:
 787         release_region(HD_DATA, 8);
 788 out2:
 789         free_irq(HD_IRQ, NULL);
 790 out1:
 791         for (drive = 0; drive < NR_HD; drive++)
 792                 put_disk(hd_gendisk[drive]);
 793         NR_HD = 0;
 794 out:
 795         del_timer(&device_timer);
 796         unregister_blkdev(HD_MAJOR, "hd");
 797         blk_cleanup_queue(hd_queue);
 798         return -1;
 799 Enomem:
 800         while (drive--)
 801                 put_disk(hd_gendisk[drive]);
 802         goto out;
 803 }
 804
 805 static int __init parse_hd_setup(char *line)
 806 {
 807         int ints[6];
 808
 809         (void) get_options(line, ARRAY_SIZE(ints), ints);
 810         hd_setup(NULL, ints);
 811
 812         return 1;
 813 }
 814 __setup("hd=", parse_hd_setup);
 815
 816 late_initcall(hd_init);