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
 102 #define MAJOR_NR HD_MAJOR
 103 #define QUEUE (hd_queue)
 104 #define CURRENT elv_next_request(hd_queue)
 105
 106 #define TIMEOUT_VALUE   (6*HZ)
 107 #define HD_DELAY        0
 108
 109 #define MAX_ERRORS     16       /* Max read/write errors/sector */
 110 #define RESET_FREQ      8       /* Reset controller every 8th retry */
 111 #define RECAL_FREQ      4       /* Recalibrate every 4th retry */
 112 #define MAX_HD          2
 113
 114 #define STAT_OK         (READY_STAT|SEEK_STAT)
 115 #define OK_STATUS(s)    (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
 116
 117 static void recal_intr(void);
 118 static void bad_rw_intr(void);
 119
 120 static int reset;
 121 static int hd_error;
 122
 123 /*
 124  *  This struct defines the HD's and their types.
 125  */
 126 struct hd_i_struct {
 127         unsigned int head, sect, cyl, wpcom, lzone, ctl;
 128         int unit;
 129         int recalibrate;
 130         int special_op;
 131 };
 132
 133 #ifdef HD_TYPE
 134 static struct hd_i_struct hd_info[] = { HD_TYPE };
 135 static int NR_HD = ARRAY_SIZE(hd_info);
 136 #else
 137 static struct hd_i_struct hd_info[MAX_HD];
 138 static int NR_HD;
 139 #endif
 140
 141 static struct gendisk *hd_gendisk[MAX_HD];
 142
 143 static struct timer_list device_timer;
 144
 145 #define TIMEOUT_VALUE (6*HZ)
 146
 147 #define SET_TIMER                                                       \
 148         do {                                                            \
 149                 mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);      \
 150         } while (0)
 151
 152 static void (*do_hd)(void) = NULL;
 153 #define SET_HANDLER(x) \
 154 if ((do_hd = (x)) != NULL) \
 155         SET_TIMER; \
 156 else \
 157         del_timer(&device_timer);
 158
 159
 160 #if (HD_DELAY > 0)
 161
 162 #include <asm/i8253.h>
 163
 164 unsigned long last_req;
 165
 166 unsigned long read_timer(void)
 167 {
 168         unsigned long t, flags;
 169         int i;
 170
 171         spin_lock_irqsave(&i8253_lock, flags);
 172         t = jiffies * 11932;
 173         outb_p(0, 0x43);
 174         i = inb_p(0x40);
 175         i |= inb(0x40) << 8;
 176         spin_unlock_irqrestore(&i8253_lock, flags);
 177         return(t - i);
 178 }
 179 #endif
 180
 181 static void __init hd_setup(char *str, int *ints)
 182 {
 183         int hdind = 0;
 184
 185         if (ints[0] != 3)
 186                 return;
 187         if (hd_info[0].head != 0)
 188                 hdind = 1;
 189         hd_info[hdind].head = ints[2];
 190         hd_info[hdind].sect = ints[3];
 191         hd_info[hdind].cyl = ints[1];
 192         hd_info[hdind].wpcom = 0;
 193         hd_info[hdind].lzone = ints[1];
 194         hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
 195         NR_HD = hdind+1;
 196 }
 197
 198 static void dump_status(const char *msg, unsigned int stat)
 199 {
 200         char *name = "hd?";
 201         if (CURRENT)
 202                 name = CURRENT->rq_disk->disk_name;
 203
 204 #ifdef VERBOSE_ERRORS
 205         printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
 206         if (stat & BUSY_STAT)   printk("Busy ");
 207         if (stat & READY_STAT)  printk("DriveReady ");
 208         if (stat & WRERR_STAT)  printk("WriteFault ");
 209         if (stat & SEEK_STAT)   printk("SeekComplete ");
 210         if (stat & DRQ_STAT)    printk("DataRequest ");
 211         if (stat & ECC_STAT)    printk("CorrectedError ");
 212         if (stat & INDEX_STAT)  printk("Index ");
 213         if (stat & ERR_STAT)    printk("Error ");
 214         printk("}\n");
 215         if ((stat & ERR_STAT) == 0) {
 216                 hd_error = 0;
 217         } else {
 218                 hd_error = inb(HD_ERROR);
 219                 printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
 220                 if (hd_error & BBD_ERR)         printk("BadSector ");
 221                 if (hd_error & ECC_ERR)         printk("UncorrectableError ");
 222                 if (hd_error & ID_ERR)          printk("SectorIdNotFound ");
 223                 if (hd_error & ABRT_ERR)        printk("DriveStatusError ");
 224                 if (hd_error & TRK0_ERR)        printk("TrackZeroNotFound ");
 225                 if (hd_error & MARK_ERR)        printk("AddrMarkNotFound ");
 226                 printk("}");
 227                 if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
 228                         printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
 229                                 inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
 230                         if (CURRENT)
 231                                 printk(", sector=%ld", CURRENT->sector);
 232                 }
 233                 printk("\n");
 234         }
 235 #else
 236         printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
 237         if ((stat & ERR_STAT) == 0) {
 238                 hd_error = 0;
 239         } else {
 240                 hd_error = inb(HD_ERROR);
 241                 printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
 242         }
 243 #endif
 244 }
 245
 246 static void check_status(void)
 247 {
 248         int i = inb_p(HD_STATUS);
 249
 250         if (!OK_STATUS(i)) {
 251                 dump_status("check_status", i);
 252                 bad_rw_intr();
 253         }
 254 }
 255
 256 static int controller_busy(void)
 257 {
 258         int retries = 100000;
 259         unsigned char status;
 260
 261         do {
 262                 status = inb_p(HD_STATUS);
 263         } while ((status & BUSY_STAT) && --retries);
 264         return status;
 265 }
 266
 267 static int status_ok(void)
 268 {
 269         unsigned char status = inb_p(HD_STATUS);
 270
 271         if (status & BUSY_STAT)
 272                 return 1;       /* Ancient, but does it make sense??? */
 273         if (status & WRERR_STAT)
 274                 return 0;
 275         if (!(status & READY_STAT))
 276                 return 0;
 277         if (!(status & SEEK_STAT))
 278                 return 0;
 279         return 1;
 280 }
 281
 282 static int controller_ready(unsigned int drive, unsigned int head)
 283 {
 284         int retry = 100;
 285
 286         do {
 287                 if (controller_busy() & BUSY_STAT)
 288                         return 0;
 289                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 290                 if (status_ok())
 291                         return 1;
 292         } while (--retry);
 293         return 0;
 294 }
 295
 296 static void hd_out(struct hd_i_struct *disk,
 297                    unsigned int nsect,
 298                    unsigned int sect,
 299                    unsigned int head,
 300                    unsigned int cyl,
 301                    unsigned int cmd,
 302                    void (*intr_addr)(void))
 303 {
 304         unsigned short port;
 305
 306 #if (HD_DELAY > 0)
 307         while (read_timer() - last_req < HD_DELAY)
 308                 /* nothing */;
 309 #endif
 310         if (reset)
 311                 return;
 312         if (!controller_ready(disk->unit, head)) {
 313                 reset = 1;
 314                 return;
 315         }
 316         SET_HANDLER(intr_addr);
 317         outb_p(disk->ctl, HD_CMD);
 318         port = HD_DATA;
 319         outb_p(disk->wpcom >> 2, ++port);
 320         outb_p(nsect, ++port);
 321         outb_p(sect, ++port);
 322         outb_p(cyl, ++port);
 323         outb_p(cyl >> 8, ++port);
 324         outb_p(0xA0 | (disk->unit << 4) | head, ++port);
 325         outb_p(cmd, ++port);
 326 }
 327
 328 static void hd_request (void);
 329
 330 static int drive_busy(void)
 331 {
 332         unsigned int i;
 333         unsigned char c;
 334
 335         for (i = 0; i < 500000 ; i++) {
 336                 c = inb_p(HD_STATUS);
 337                 if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
 338                         return 0;
 339         }
 340         dump_status("reset timed out", c);
 341         return 1;
 342 }
 343
 344 static void reset_controller(void)
 345 {
 346         int     i;
 347
 348         outb_p(4, HD_CMD);
 349         for (i = 0; i < 1000; i++) barrier();
 350         outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
 351         for (i = 0; i < 1000; i++) barrier();
 352         if (drive_busy())
 353                 printk("hd: controller still busy\n");
 354         else if ((hd_error = inb(HD_ERROR)) != 1)
 355                 printk("hd: controller reset failed: %02x\n", hd_error);
 356 }
 357
 358 static void reset_hd(void)
 359 {
 360         static int i;
 361
 362 repeat:
 363         if (reset) {
 364                 reset = 0;
 365                 i = -1;
 366                 reset_controller();
 367         } else {
 368                 check_status();
 369                 if (reset)
 370                         goto repeat;
 371         }
 372         if (++i < NR_HD) {
 373                 struct hd_i_struct *disk = &hd_info[i];
 374                 disk->special_op = disk->recalibrate = 1;
 375                 hd_out(disk, disk->sect, disk->sect, disk->head-1,
 376                         disk->cyl, ATA_CMD_INIT_DEV_PARAMS, &reset_hd);
 377                 if (reset)
 378                         goto repeat;
 379         } else
 380                 hd_request();
 381 }
 382
 383 /*
 384  * Ok, don't know what to do with the unexpected interrupts: on some machines
 385  * doing a reset and a retry seems to result in an eternal loop. Right now I
 386  * ignore it, and just set the timeout.
 387  *
 388  * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 389  * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 390  * "good", we just ignore the interrupt completely.
 391  */
 392 static void unexpected_hd_interrupt(void)
 393 {
 394         unsigned int stat = inb_p(HD_STATUS);
 395
 396         if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
 397                 dump_status("unexpected interrupt", stat);
 398                 SET_TIMER;
 399         }
 400 }
 401
 402 /*
 403  * bad_rw_intr() now tries to be a bit smarter and does things
 404  * according to the error returned by the controller.
 405  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 406  */
 407 static void bad_rw_intr(void)
 408 {
 409         struct request *req = CURRENT;
 410         if (req != NULL) {
 411                 struct hd_i_struct *disk = req->rq_disk->private_data;
 412                 if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 413                         end_request(req, 0);
 414                         disk->special_op = disk->recalibrate = 1;
 415                 } else if (req->errors % RESET_FREQ == 0)
 416                         reset = 1;
 417                 else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
 418                         disk->special_op = disk->recalibrate = 1;
 419                 /* Otherwise just retry */
 420         }
 421 }
 422
 423 static inline int wait_DRQ(void)
 424 {
 425         int retries;
 426         int stat;
 427
 428         for (retries = 0; retries < 100000; retries++) {
 429                 stat = inb_p(HD_STATUS);
 430                 if (stat & DRQ_STAT)
 431                         return 0;
 432         }
 433         dump_status("wait_DRQ", stat);
 434         return -1;
 435 }
 436
 437 static void read_intr(void)
 438 {
 439         struct request *req;
 440         int i, retries = 100000;
 441
 442         do {
 443                 i = (unsigned) inb_p(HD_STATUS);
 444                 if (i & BUSY_STAT)
 445                         continue;
 446                 if (!OK_STATUS(i))
 447                         break;
 448                 if (i & DRQ_STAT)
 449                         goto ok_to_read;
 450         } while (--retries > 0);
 451         dump_status("read_intr", i);
 452         bad_rw_intr();
 453         hd_request();
 454         return;
 455 ok_to_read:
 456         req = CURRENT;
 457         insw(HD_DATA, req->buffer, 256);
 458         req->sector++;
 459         req->buffer += 512;
 460         req->errors = 0;
 461         i = --req->nr_sectors;
 462         --req->current_nr_sectors;
 463 #ifdef DEBUG
 464         printk("%s: read: sector %ld, remaining = %ld, buffer=%p\n",
 465                 req->rq_disk->disk_name, req->sector, req->nr_sectors,
 466                 req->buffer+512);
 467 #endif
 468         if (req->current_nr_sectors <= 0)
 469                 end_request(req, 1);
 470         if (i > 0) {
 471                 SET_HANDLER(&read_intr);
 472                 return;
 473         }
 474         (void) inb_p(HD_STATUS);
 475 #if (HD_DELAY > 0)
 476         last_req = read_timer();
 477 #endif
 478         if (elv_next_request(QUEUE))
 479                 hd_request();
 480         return;
 481 }
 482
 483 static void write_intr(void)
 484 {
 485         struct request *req = CURRENT;
 486         int i;
 487         int retries = 100000;
 488
 489         do {
 490                 i = (unsigned) inb_p(HD_STATUS);
 491                 if (i & BUSY_STAT)
 492                         continue;
 493                 if (!OK_STATUS(i))
 494                         break;
 495                 if ((req->nr_sectors <= 1) || (i & DRQ_STAT))
 496                         goto ok_to_write;
 497         } while (--retries > 0);
 498         dump_status("write_intr", i);
 499         bad_rw_intr();
 500         hd_request();
 501         return;
 502 ok_to_write:
 503         req->sector++;
 504         i = --req->nr_sectors;
 505         --req->current_nr_sectors;
 506         req->buffer += 512;
 507         if (!i || (req->bio && req->current_nr_sectors <= 0))
 508                 end_request(req, 1);
 509         if (i > 0) {
 510                 SET_HANDLER(&write_intr);
 511                 outsw(HD_DATA, req->buffer, 256);
 512                 local_irq_enable();
 513         } else {
 514 #if (HD_DELAY > 0)
 515                 last_req = read_timer();
 516 #endif
 517                 hd_request();
 518         }
 519         return;
 520 }
 521
 522 static void recal_intr(void)
 523 {
 524         check_status();
 525 #if (HD_DELAY > 0)
 526         last_req = read_timer();
 527 #endif
 528         hd_request();
 529 }
 530
 531 /*
 532  * This is another of the error-routines I don't know what to do with. The
 533  * best idea seems to just set reset, and start all over again.
 534  */
 535 static void hd_times_out(unsigned long dummy)
 536 {
 537         char *name;
 538
 539         do_hd = NULL;
 540
 541         if (!CURRENT)
 542                 return;
 543
 544         disable_irq(HD_IRQ);
 545         local_irq_enable();
 546         reset = 1;
 547         name = CURRENT->rq_disk->disk_name;
 548         printk("%s: timeout\n", name);
 549         if (++CURRENT->errors >= MAX_ERRORS) {
 550 #ifdef DEBUG
 551                 printk("%s: too many errors\n", name);
 552 #endif
 553                 end_request(CURRENT, 0);
 554         }
 555         local_irq_disable();
 556         hd_request();
 557         enable_irq(HD_IRQ);
 558 }
 559
 560 static int do_special_op(struct hd_i_struct *disk, struct request *req)
 561 {
 562         if (disk->recalibrate) {
 563                 disk->recalibrate = 0;
 564                 hd_out(disk, disk->sect, 0, 0, 0, ATA_CMD_RESTORE, &recal_intr);
 565                 return reset;
 566         }
 567         if (disk->head > 16) {
 568                 printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
 569                 end_request(req, 0);
 570         }
 571         disk->special_op = 0;
 572         return 1;
 573 }
 574
 575 /*
 576  * The driver enables interrupts as much as possible.  In order to do this,
 577  * (a) the device-interrupt is disabled before entering hd_request(),
 578  * and (b) the timeout-interrupt is disabled before the sti().
 579  *
 580  * Interrupts are still masked (by default) whenever we are exchanging
 581  * data/cmds with a drive, because some drives seem to have very poor
 582  * tolerance for latency during I/O. The IDE driver has support to unmask
 583  * interrupts for non-broken hardware, so use that driver if required.
 584  */
 585 static void hd_request(void)
 586 {
 587         unsigned int block, nsect, sec, track, head, cyl;
 588         struct hd_i_struct *disk;
 589         struct request *req;
 590
 591         if (do_hd)
 592                 return;
 593 repeat:
 594         del_timer(&device_timer);
 595         local_irq_enable();
 596
 597         req = CURRENT;
 598         if (!req) {
 599                 do_hd = NULL;
 600                 return;
 601         }
 602
 603         if (reset) {
 604                 local_irq_disable();
 605                 reset_hd();
 606                 return;
 607         }
 608         disk = req->rq_disk->private_data;
 609         block = req->sector;
 610         nsect = req->nr_sectors;
 611         if (block >= get_capacity(req->rq_disk) ||
 612             ((block+nsect) > get_capacity(req->rq_disk))) {
 613                 printk("%s: bad access: block=%d, count=%d\n",
 614                         req->rq_disk->disk_name, block, nsect);
 615                 end_request(req, 0);
 616                 goto repeat;
 617         }
 618
 619         if (disk->special_op) {
 620                 if (do_special_op(disk, req))
 621                         goto repeat;
 622                 return;
 623         }
 624         sec   = block % disk->sect + 1;
 625         track = block / disk->sect;
 626         head  = track % disk->head;
 627         cyl   = track / disk->head;
 628 #ifdef DEBUG
 629         printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
 630                 req->rq_disk->disk_name,
 631                 req_data_dir(req) == READ ? "read" : "writ",
 632                 cyl, head, sec, nsect, req->buffer);
 633 #endif
 634         if (blk_fs_request(req)) {
 635                 switch (rq_data_dir(req)) {
 636                 case READ:
 637                         hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_READ,
 638                                 &read_intr);
 639                         if (reset)
 640                                 goto repeat;
 641                         break;
 642                 case WRITE:
 643                         hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_WRITE,
 644                                 &write_intr);
 645                         if (reset)
 646                                 goto repeat;
 647                         if (wait_DRQ()) {
 648                                 bad_rw_intr();
 649                                 goto repeat;
 650                         }
 651                         outsw(HD_DATA, req->buffer, 256);
 652                         break;
 653                 default:
 654                         printk("unknown hd-command\n");
 655                         end_request(req, 0);
 656                         break;
 657                 }
 658         }
 659 }
 660
 661 static void do_hd_request(struct request_queue *q)
 662 {
 663         disable_irq(HD_IRQ);
 664         hd_request();
 665         enable_irq(HD_IRQ);
 666 }
 667
 668 static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 669 {
 670         struct hd_i_struct *disk = bdev->bd_disk->private_data;
 671
 672         geo->heads = disk->head;
 673         geo->sectors = disk->sect;
 674         geo->cylinders = disk->cyl;
 675         return 0;
 676 }
 677
 678 /*
 679  * Releasing a block device means we sync() it, so that it can safely
 680  * be forgotten about...
 681  */
 682
 683 static irqreturn_t hd_interrupt(int irq, void *dev_id)
 684 {
 685         void (*handler)(void) = do_hd;
 686
 687         do_hd = NULL;
 688         del_timer(&device_timer);
 689         if (!handler)
 690                 handler = unexpected_hd_interrupt;
 691         handler();
 692         local_irq_enable();
 693         return IRQ_HANDLED;
 694 }
 695
 696 static struct block_device_operations hd_fops = {
 697         .getgeo =       hd_getgeo,
 698 };
 699
 700 /*
 701  * This is the hard disk IRQ description. The IRQF_DISABLED in sa_flags
 702  * means we run the IRQ-handler with interrupts disabled:  this is bad for
 703  * interrupt latency, but anything else has led to problems on some
 704  * machines.
 705  *
 706  * We enable interrupts in some of the routines after making sure it's
 707  * safe.
 708  */
 709
 710 static int __init hd_init(void)
 711 {
 712         int drive;
 713
 714         if (register_blkdev(MAJOR_NR, "hd"))
 715                 return -1;
 716
 717         hd_queue = blk_init_queue(do_hd_request, &hd_lock);
 718         if (!hd_queue) {
 719                 unregister_blkdev(MAJOR_NR, "hd");
 720                 return -ENOMEM;
 721         }
 722
 723         blk_queue_max_sectors(hd_queue, 255);
 724         init_timer(&device_timer);
 725         device_timer.function = hd_times_out;
 726         blk_queue_hardsect_size(hd_queue, 512);
 727
 728         if (!NR_HD) {
 729                 /*
 730                  * We don't know anything about the drive.  This means
 731                  * that you *MUST* specify the drive parameters to the
 732                  * kernel yourself.
 733                  *
 734                  * If we were on an i386, we used to read this info from
 735                  * the BIOS or CMOS.  This doesn't work all that well,
 736                  * since this assumes that this is a primary or secondary
 737                  * drive, and if we're using this legacy driver, it's
 738                  * probably an auxilliary controller added to recover
 739                  * legacy data off an ST-506 drive.  Either way, it's
 740                  * definitely safest to have the user explicitly specify
 741                  * the information.
 742                  */
 743                 printk("hd: no drives specified - use hd=cyl,head,sectors"
 744                         " on kernel command line\n");
 745                 goto out;
 746         }
 747
 748         for (drive = 0 ; drive < NR_HD ; drive++) {
 749                 struct gendisk *disk = alloc_disk(64);
 750                 struct hd_i_struct *p = &hd_info[drive];
 751                 if (!disk)
 752                         goto Enomem;
 753                 disk->major = MAJOR_NR;
 754                 disk->first_minor = drive << 6;
 755                 disk->fops = &hd_fops;
 756                 sprintf(disk->disk_name, "hd%c", 'a'+drive);
 757                 disk->private_data = p;
 758                 set_capacity(disk, p->head * p->sect * p->cyl);
 759                 disk->queue = hd_queue;
 760                 p->unit = drive;
 761                 hd_gendisk[drive] = disk;
 762                 printk("%s: %luMB, CHS=%d/%d/%d\n",
 763                         disk->disk_name, (unsigned long)get_capacity(disk)/2048,
 764                         p->cyl, p->head, p->sect);
 765         }
 766
 767         if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
 768                 printk("hd: unable to get IRQ%d for the hard disk driver\n",
 769                         HD_IRQ);
 770                 goto out1;
 771         }
 772         if (!request_region(HD_DATA, 8, "hd")) {
 773                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
 774                 goto out2;
 775         }
 776         if (!request_region(HD_CMD, 1, "hd(cmd)")) {
 777                 printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
 778                 goto out3;
 779         }
 780
 781         /* Let them fly */
 782         for (drive = 0; drive < NR_HD; drive++)
 783                 add_disk(hd_gendisk[drive]);
 784
 785         return 0;
 786
 787 out3:
 788         release_region(HD_DATA, 8);
 789 out2:
 790         free_irq(HD_IRQ, NULL);
 791 out1:
 792         for (drive = 0; drive < NR_HD; drive++)
 793                 put_disk(hd_gendisk[drive]);
 794         NR_HD = 0;
 795 out:
 796         del_timer(&device_timer);
 797         unregister_blkdev(MAJOR_NR, "hd");
 798         blk_cleanup_queue(hd_queue);
 799         return -1;
 800 Enomem:
 801         while (drive--)
 802                 put_disk(hd_gendisk[drive]);
 803         goto out;
 804 }
 805
 806 static int __init parse_hd_setup(char *line)
 807 {
 808         int ints[6];
 809
 810         (void) get_options(line, ARRAY_SIZE(ints), ints);
 811         hd_setup(NULL, ints);
 812
 813         return 1;
 814 }
 815 __setup("hd=", parse_hd_setup);
 816
 817 late_initcall(hd_init);