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/hdreg.h>
  43
  44 #define REALLY_SLOW_IO
  45 #include <asm/system.h>
  46 #include <asm/io.h>
  47 #include <asm/uaccess.h>
  48
  49 #ifdef __arm__
  50 #undef  HD_IRQ
  51 #endif
  52 #include <asm/irq.h>
  53 #ifdef __arm__
  54 #define HD_IRQ IRQ_HARDDISK
  55 #endif
  56
  57 /* Hd controller regster ports */
  58
  59 #define HD_DATA         0x1f0           /* _CTL when writing */
  60 #define HD_ERROR        0x1f1           /* see err-bits */
  61 #define HD_NSECTOR      0x1f2           /* nr of sectors to read/write */
  62 #define HD_SECTOR       0x1f3           /* starting sector */
  63 #define HD_LCYL         0x1f4           /* starting cylinder */
  64 #define HD_HCYL         0x1f5           /* high byte of starting cyl */
  65 #define HD_CURRENT      0x1f6           /* 101dhhhh , d=drive, hhhh=head */
  66 #define HD_STATUS       0x1f7           /* see status-bits */
  67 #define HD_FEATURE      HD_ERROR        /* same io address, read=error, write=feature */
  68 #define HD_PRECOMP      HD_FEATURE      /* obsolete use of this port - predates IDE */
  69 #define HD_COMMAND      HD_STATUS       /* same io address, read=status, write=cmd */
  70
  71 #define HD_CMD          0x3f6           /* used for resets */
  72 #define HD_ALTSTATUS    0x3f6           /* same as HD_STATUS but doesn't clear irq */
  73
  74 /* Bits of HD_STATUS */
  75 #define ERR_STAT                0x01
  76 #define INDEX_STAT              0x02
  77 #define ECC_STAT                0x04    /* Corrected error */
  78 #define DRQ_STAT                0x08
  79 #define SEEK_STAT               0x10
  80 #define SERVICE_STAT            SEEK_STAT
  81 #define WRERR_STAT              0x20
  82 #define READY_STAT              0x40
  83 #define BUSY_STAT               0x80
  84
  85 /* Bits for HD_ERROR */
  86 #define MARK_ERR                0x01    /* Bad address mark */
  87 #define TRK0_ERR                0x02    /* couldn't find track 0 */
  88 #define ABRT_ERR                0x04    /* Command aborted */
  89 #define MCR_ERR                 0x08    /* media change request */
  90 #define ID_ERR                  0x10    /* ID field not found */
  91 #define MC_ERR                  0x20    /* media changed */
  92 #define ECC_ERR                 0x40    /* Uncorrectable ECC error */
  93 #define BBD_ERR                 0x80    /* pre-EIDE meaning:  block marked bad */
  94 #define ICRC_ERR                0x80    /* new meaning:  CRC error during transfer */
  95
  96 static DEFINE_SPINLOCK(hd_lock);
  97 static struct request_queue *hd_queue;
  98
  99 #define MAJOR_NR HD_MAJOR
 100 #define QUEUE (hd_queue)
 101 #define CURRENT elv_next_request(hd_queue)
 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 void dump_status(const char *msg, unsigned int stat)
 196 {
 197         char *name = "hd?";
 198         if (CURRENT)
 199                 name = CURRENT->rq_disk->disk_name;
 200
 201 #ifdef VERBOSE_ERRORS
 202         printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
 203         if (stat & BUSY_STAT)   printk("Busy ");
 204         if (stat & READY_STAT)  printk("DriveReady ");
 205         if (stat & WRERR_STAT)  printk("WriteFault ");
 206         if (stat & SEEK_STAT)   printk("SeekComplete ");
 207         if (stat & DRQ_STAT)    printk("DataRequest ");
 208         if (stat & ECC_STAT)    printk("CorrectedError ");
 209         if (stat & INDEX_STAT)  printk("Index ");
 210         if (stat & ERR_STAT)    printk("Error ");
 211         printk("}\n");
 212         if ((stat & ERR_STAT) == 0) {
 213                 hd_error = 0;
 214         } else {
 215                 hd_error = inb(HD_ERROR);
 216                 printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
 217                 if (hd_error & BBD_ERR)         printk("BadSector ");
 218                 if (hd_error & ECC_ERR)         printk("UncorrectableError ");
 219                 if (hd_error & ID_ERR)          printk("SectorIdNotFound ");
 220                 if (hd_error & ABRT_ERR)        printk("DriveStatusError ");
 221                 if (hd_error & TRK0_ERR)        printk("TrackZeroNotFound ");
 222                 if (hd_error & MARK_ERR)        printk("AddrMarkNotFound ");
 223                 printk("}");
 224                 if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
 225                         printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
 226                                 inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
 227                         if (CURRENT)
 228                                 printk(", sector=%ld", CURRENT->sector);
 229                 }
 230                 printk("\n");
 231         }
 232 #else
 233         printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
 234         if ((stat & ERR_STAT) == 0) {
 235                 hd_error = 0;
 236         } else {
 237                 hd_error = inb(HD_ERROR);
 238                 printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
 239         }
 240 #endif
 241 }
 242
 243 static void check_status(void)
 244 {
 245         int i = inb_p(HD_STATUS);
 246
 247         if (!OK_STATUS(i)) {
 248                 dump_status("check_status", i);
 249                 bad_rw_intr();
 250         }
 251 }
 252
 253 static int controller_busy(void)
 254 {
 255         int retries = 100000;
 256         unsigned char status;
 257
 258         do {
 259                 status = inb_p(HD_STATUS);
 260         } while ((status & BUSY_STAT) && --retries);
 261         return status;
 262 }
 263
 264 static int status_ok(void)
 265 {
 266         unsigned char status = inb_p(HD_STATUS);
 267
 268         if (status & BUSY_STAT)
 269                 return 1;       /* Ancient, but does it make sense??? */
 270         if (status & WRERR_STAT)
 271                 return 0;
 272         if (!(status & READY_STAT))
 273                 return 0;
 274         if (!(status & SEEK_STAT))
 275                 return 0;
 276         return 1;
 277 }
 278
 279 static int controller_ready(unsigned int drive, unsigned int head)
 280 {
 281         int retry = 100;
 282
 283         do {
 284                 if (controller_busy() & BUSY_STAT)
 285                         return 0;
 286                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 287                 if (status_ok())
 288                         return 1;
 289         } while (--retry);
 290         return 0;
 291 }
 292
 293 static void hd_out(struct hd_i_struct *disk,
 294                    unsigned int nsect,
 295                    unsigned int sect,
 296                    unsigned int head,
 297                    unsigned int cyl,
 298                    unsigned int cmd,
 299                    void (*intr_addr)(void))
 300 {
 301         unsigned short port;
 302
 303 #if (HD_DELAY > 0)
 304         while (read_timer() - last_req < HD_DELAY)
 305                 /* nothing */;
 306 #endif
 307         if (reset)
 308                 return;
 309         if (!controller_ready(disk->unit, head)) {
 310                 reset = 1;
 311                 return;
 312         }
 313         SET_HANDLER(intr_addr);
 314         outb_p(disk->ctl, HD_CMD);
 315         port = HD_DATA;
 316         outb_p(disk->wpcom >> 2, ++port);
 317         outb_p(nsect, ++port);
 318         outb_p(sect, ++port);
 319         outb_p(cyl, ++port);
 320         outb_p(cyl >> 8, ++port);
 321         outb_p(0xA0 | (disk->unit << 4) | head, ++port);
 322         outb_p(cmd, ++port);
 323 }
 324
 325 static void hd_request (void);
 326
 327 static int drive_busy(void)
 328 {
 329         unsigned int i;
 330         unsigned char c;
 331
 332         for (i = 0; i < 500000 ; i++) {
 333                 c = inb_p(HD_STATUS);
 334                 if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
 335                         return 0;
 336         }
 337         dump_status("reset timed out", c);
 338         return 1;
 339 }
 340
 341 static void reset_controller(void)
 342 {
 343         int     i;
 344
 345         outb_p(4, HD_CMD);
 346         for (i = 0; i < 1000; i++) barrier();
 347         outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
 348         for (i = 0; i < 1000; i++) barrier();
 349         if (drive_busy())
 350                 printk("hd: controller still busy\n");
 351         else if ((hd_error = inb(HD_ERROR)) != 1)
 352                 printk("hd: controller reset failed: %02x\n", hd_error);
 353 }
 354
 355 static void reset_hd(void)
 356 {
 357         static int i;
 358
 359 repeat:
 360         if (reset) {
 361                 reset = 0;
 362                 i = -1;
 363                 reset_controller();
 364         } else {
 365                 check_status();
 366                 if (reset)
 367                         goto repeat;
 368         }
 369         if (++i < NR_HD) {
 370                 struct hd_i_struct *disk = &hd_info[i];
 371                 disk->special_op = disk->recalibrate = 1;
 372                 hd_out(disk, disk->sect, disk->sect, disk->head-1,
 373                         disk->cyl, WIN_SPECIFY, &reset_hd);
 374                 if (reset)
 375                         goto repeat;
 376         } else
 377                 hd_request();
 378 }
 379
 380 /*
 381  * Ok, don't know what to do with the unexpected interrupts: on some machines
 382  * doing a reset and a retry seems to result in an eternal loop. Right now I
 383  * ignore it, and just set the timeout.
 384  *
 385  * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 386  * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 387  * "good", we just ignore the interrupt completely.
 388  */
 389 static void unexpected_hd_interrupt(void)
 390 {
 391         unsigned int stat = inb_p(HD_STATUS);
 392
 393         if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
 394                 dump_status("unexpected interrupt", stat);
 395                 SET_TIMER;
 396         }
 397 }
 398
 399 /*
 400  * bad_rw_intr() now tries to be a bit smarter and does things
 401  * according to the error returned by the controller.
 402  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 403  */
 404 static void bad_rw_intr(void)
 405 {
 406         struct request *req = CURRENT;
 407         if (req != NULL) {
 408                 struct hd_i_struct *disk = req->rq_disk->private_data;
 409                 if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 410                         end_request(req, 0);
 411                         disk->special_op = disk->recalibrate = 1;
 412                 } else if (req->errors % RESET_FREQ == 0)
 413                         reset = 1;
 414                 else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
 415                         disk->special_op = disk->recalibrate = 1;
 416                 /* Otherwise just retry */
 417         }
 418 }
 419
 420 static inline int wait_DRQ(void)
 421 {
 422         int retries;
 423         int stat;
 424
 425         for (retries = 0; retries < 100000; retries++) {
 426                 stat = inb_p(HD_STATUS);
 427                 if (stat & DRQ_STAT)
 428                         return 0;
 429         }
 430         dump_status("wait_DRQ", stat);
 431         return -1;
 432 }
 433
 434 static void read_intr(void)
 435 {
 436         struct request *req;
 437         int i, retries = 100000;
 438
 439         do {
 440                 i = (unsigned) inb_p(HD_STATUS);
 441                 if (i & BUSY_STAT)
 442                         continue;
 443                 if (!OK_STATUS(i))
 444                         break;
 445                 if (i & DRQ_STAT)
 446                         goto ok_to_read;
 447         } while (--retries > 0);
 448         dump_status("read_intr", i);
 449         bad_rw_intr();
 450         hd_request();
 451         return;
 452 ok_to_read:
 453         req = CURRENT;
 454         insw(HD_DATA, req->buffer, 256);
 455         req->sector++;
 456         req->buffer += 512;
 457         req->errors = 0;
 458         i = --req->nr_sectors;
 459         --req->current_nr_sectors;
 460 #ifdef DEBUG
 461         printk("%s: read: sector %ld, remaining = %ld, buffer=%p\n",
 462                 req->rq_disk->disk_name, req->sector, req->nr_sectors,
 463                 req->buffer+512);
 464 #endif
 465         if (req->current_nr_sectors <= 0)
 466                 end_request(req, 1);
 467         if (i > 0) {
 468                 SET_HANDLER(&read_intr);
 469                 return;
 470         }
 471         (void) inb_p(HD_STATUS);
 472 #if (HD_DELAY > 0)
 473         last_req = read_timer();
 474 #endif
 475         if (elv_next_request(QUEUE))
 476                 hd_request();
 477         return;
 478 }
 479
 480 static void write_intr(void)
 481 {
 482         struct request *req = CURRENT;
 483         int i;
 484         int retries = 100000;
 485
 486         do {
 487                 i = (unsigned) inb_p(HD_STATUS);
 488                 if (i & BUSY_STAT)
 489                         continue;
 490                 if (!OK_STATUS(i))
 491                         break;
 492                 if ((req->nr_sectors <= 1) || (i & DRQ_STAT))
 493                         goto ok_to_write;
 494         } while (--retries > 0);
 495         dump_status("write_intr", i);
 496         bad_rw_intr();
 497         hd_request();
 498         return;
 499 ok_to_write:
 500         req->sector++;
 501         i = --req->nr_sectors;
 502         --req->current_nr_sectors;
 503         req->buffer += 512;
 504         if (!i || (req->bio && req->current_nr_sectors <= 0))
 505                 end_request(req, 1);
 506         if (i > 0) {
 507                 SET_HANDLER(&write_intr);
 508                 outsw(HD_DATA, req->buffer, 256);
 509                 local_irq_enable();
 510         } else {
 511 #if (HD_DELAY > 0)
 512                 last_req = read_timer();
 513 #endif
 514                 hd_request();
 515         }
 516         return;
 517 }
 518
 519 static void recal_intr(void)
 520 {
 521         check_status();
 522 #if (HD_DELAY > 0)
 523         last_req = read_timer();
 524 #endif
 525         hd_request();
 526 }
 527
 528 /*
 529  * This is another of the error-routines I don't know what to do with. The
 530  * best idea seems to just set reset, and start all over again.
 531  */
 532 static void hd_times_out(unsigned long dummy)
 533 {
 534         char *name;
 535
 536         do_hd = NULL;
 537
 538         if (!CURRENT)
 539                 return;
 540
 541         disable_irq(HD_IRQ);
 542         local_irq_enable();
 543         reset = 1;
 544         name = CURRENT->rq_disk->disk_name;
 545         printk("%s: timeout\n", name);
 546         if (++CURRENT->errors >= MAX_ERRORS) {
 547 #ifdef DEBUG
 548                 printk("%s: too many errors\n", name);
 549 #endif
 550                 end_request(CURRENT, 0);
 551         }
 552         local_irq_disable();
 553         hd_request();
 554         enable_irq(HD_IRQ);
 555 }
 556
 557 static int do_special_op(struct hd_i_struct *disk, struct request *req)
 558 {
 559         if (disk->recalibrate) {
 560                 disk->recalibrate = 0;
 561                 hd_out(disk, disk->sect, 0, 0, 0, WIN_RESTORE, &recal_intr);
 562                 return reset;
 563         }
 564         if (disk->head > 16) {
 565                 printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
 566                 end_request(req, 0);
 567         }
 568         disk->special_op = 0;
 569         return 1;
 570 }
 571
 572 /*
 573  * The driver enables interrupts as much as possible.  In order to do this,
 574  * (a) the device-interrupt is disabled before entering hd_request(),
 575  * and (b) the timeout-interrupt is disabled before the sti().
 576  *
 577  * Interrupts are still masked (by default) whenever we are exchanging
 578  * data/cmds with a drive, because some drives seem to have very poor
 579  * tolerance for latency during I/O. The IDE driver has support to unmask
 580  * interrupts for non-broken hardware, so use that driver if required.
 581  */
 582 static void hd_request(void)
 583 {
 584         unsigned int block, nsect, sec, track, head, cyl;
 585         struct hd_i_struct *disk;
 586         struct request *req;
 587
 588         if (do_hd)
 589                 return;
 590 repeat:
 591         del_timer(&device_timer);
 592         local_irq_enable();
 593
 594         req = CURRENT;
 595         if (!req) {
 596                 do_hd = NULL;
 597                 return;
 598         }
 599
 600         if (reset) {
 601                 local_irq_disable();
 602                 reset_hd();
 603                 return;
 604         }
 605         disk = req->rq_disk->private_data;
 606         block = req->sector;
 607         nsect = req->nr_sectors;
 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                 end_request(req, 0);
 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, WIN_READ,
 635                                 &read_intr);
 636                         if (reset)
 637                                 goto repeat;
 638                         break;
 639                 case WRITE:
 640                         hd_out(disk, nsect, sec, head, cyl, WIN_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                         end_request(req, 0);
 653                         break;
 654                 }
 655         }
 656 }
 657
 658 static void do_hd_request(struct request_queue *q)
 659 {
 660         disable_irq(HD_IRQ);
 661         hd_request();
 662         enable_irq(HD_IRQ);
 663 }
 664
 665 static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 666 {
 667         struct hd_i_struct *disk = bdev->bd_disk->private_data;
 668
 669         geo->heads = disk->head;
 670         geo->sectors = disk->sect;
 671         geo->cylinders = disk->cyl;
 672         return 0;
 673 }
 674
 675 /*
 676  * Releasing a block device means we sync() it, so that it can safely
 677  * be forgotten about...
 678  */
 679
 680 static irqreturn_t hd_interrupt(int irq, void *dev_id)
 681 {
 682         void (*handler)(void) = do_hd;
 683
 684         do_hd = NULL;
 685         del_timer(&device_timer);
 686         if (!handler)
 687                 handler = unexpected_hd_interrupt;
 688         handler();
 689         local_irq_enable();
 690         return IRQ_HANDLED;
 691 }
 692
 693 static 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(MAJOR_NR, "hd"))
 712                 return -1;
 713
 714         hd_queue = blk_init_queue(do_hd_request, &hd_lock);
 715         if (!hd_queue) {
 716                 unregister_blkdev(MAJOR_NR, "hd");
 717                 return -ENOMEM;
 718         }
 719
 720         blk_queue_max_sectors(hd_queue, 255);
 721         init_timer(&device_timer);
 722         device_timer.function = hd_times_out;
 723         blk_queue_hardsect_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 auxilliary 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 = MAJOR_NR;
 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(MAJOR_NR, "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);