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