drivers/block/hd.c

/* */
This source file includes following definitions.
CMOS_READ
read_timer
hd_setup
win_result
controller_ready
status_ok
controller_busy
hd_out
drive_busy
reset_controller
reset_hd
unexpected_hd_interrupt
bad_rw_intr
wait_DRQ
read_intr
write_intr
recal_intr
hd_times_out
do_hd_request
hd_ioctl
hd_open
hd_release
hd_interrupt
hd_geninit
hd_init
revalidate_hddisk
   1 /*
   2  *  linux/kernel/hd.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 /*
   8  * This is the low-level hd interrupt support. It traverses the
   9  * request-list, using interrupts to jump between functions. As
  10  * all the functions are called within interrupts, we may not
  11  * sleep. Special care is recommended.
  12  * 
  13  *  modified by Drew Eckhardt to check nr of hd's from the CMOS.
  14  *
  15  *  Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
  16  *  in the early extended-partition checks and added DM partitions
  17  */
  18 
  19 
  20 #include <linux/errno.h>
  21 #include <linux/signal.h>
  22 #include <linux/sched.h>
  23 #include <linux/timer.h>
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/hdreg.h>
  27 #include <linux/genhd.h>
  28 #include <linux/config.h>
  29 
  30 #define REALLY_SLOW_IO
  31 #include <asm/system.h>
  32 #include <asm/io.h>
  33 #include <asm/segment.h>
  34 
  35 #define MAJOR_NR HD_MAJOR
  36 #include "blk.h"
  37 
  38 #define HD_IRQ 14
  39 
  40 static int revalidate_hddisk(int, int);
  41 
  42 static inline unsigned char CMOS_READ(unsigned char addr)
     /*  */
  43 {
  44         outb_p(addr,0x70);
  45         return inb_p(0x71);
  46 }
  47 
  48 #define HD_DELAY        0
  49 
  50 #define MAX_ERRORS     16       /* Max read/write errors/sector */
  51 #define RESET_FREQ      8       /* Reset controller every 8th retry */
  52 #define RECAL_FREQ      4       /* Recalibrate every 4th retry */
  53 #define MAX_HD          2
  54 
  55 static void recal_intr(void);
  56 static void bad_rw_intr(void);
  57 
  58 static char recalibrate[ MAX_HD ] = { 0, };
  59 static int access_count[MAX_HD] = {0, };
  60 static char busy[MAX_HD] = {0, };
  61 static struct wait_queue * busy_wait = NULL;
  62 
  63 static int reset = 0;
  64 static int hd_error = 0;
  65 
  66 #if (HD_DELAY > 0)
  67 unsigned long last_req, read_timer();
  68 #endif
  69 
  70 /*
  71  *  This struct defines the HD's and their types.
  72  */
  73 struct hd_i_struct {
  74         unsigned int head,sect,cyl,wpcom,lzone,ctl;
  75         };
  76 #ifdef HD_TYPE
  77 struct hd_i_struct hd_info[] = { HD_TYPE };
  78 static int NR_HD = ((sizeof (hd_info))/(sizeof (struct hd_i_struct)));
  79 #else
  80 struct hd_i_struct hd_info[] = { {0,0,0,0,0,0},{0,0,0,0,0,0} };
  81 static int NR_HD = 0;
  82 #endif
  83 
  84 static struct hd_struct hd[MAX_HD<<6]={{0,0},};
  85 static int hd_sizes[MAX_HD<<6] = {0, };
  86 static int hd_blocksizes[MAX_HD<<6] = {0, };
  87 
  88 #if (HD_DELAY > 0)
  89 unsigned long read_timer(void)
     /*  */
  90 {
  91         unsigned long t;
  92         int i;
  93 
  94         cli();
  95         t = jiffies * 11932;
  96         outb_p(0, 0x43);
  97         i = inb_p(0x40);
  98         i |= inb(0x40) << 8;
  99         sti();
 100         return(t - i);
 101 }
 102 #endif
 103 
 104 void hd_setup(char *str, int *ints)
     /*  */
 105 {
 106         int hdind = 0;
 107 
 108         if (ints[0] != 3)
 109                 return;
 110         if (hd_info[0].head != 0)
 111                 hdind=1;
 112         hd_info[hdind].head = ints[2];
 113         hd_info[hdind].sect = ints[3];
 114         hd_info[hdind].cyl = ints[1];
 115         hd_info[hdind].wpcom = 0;
 116         hd_info[hdind].lzone = ints[1];
 117         hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
 118         NR_HD = hdind+1;
 119 }
 120 
 121 static int win_result(void)
     /*  */
 122 {
 123         int i=inb_p(HD_STATUS);
 124 
 125         if ((i & (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT))
 126                 == (READY_STAT | SEEK_STAT)) {
 127                 hd_error = 0;
 128                 return 0; /* ok */
 129         }
 130         printk("HD: win_result: status = 0x%02x\n",i);
 131         if (i&1) {
 132                 hd_error = inb(HD_ERROR);
 133                 printk("HD: win_result: error = 0x%02x\n",hd_error);
 134         }       
 135         return 1;
 136 }
 137 
 138 static int controller_busy(void);
 139 static int status_ok(void);
 140 
 141 static int controller_ready(unsigned int drive, unsigned int head)
     /*  */
 142 {
 143         int retry = 100;
 144 
 145         do {
 146                 if (controller_busy() & BUSY_STAT)
 147                         return 0;
 148                 outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
 149                 if (status_ok())
 150                         return 1;
 151         } while (--retry);
 152         return 0;
 153 }
 154 
 155 static int status_ok(void)
     /*  */
 156 {
 157         unsigned char status = inb_p(HD_STATUS);
 158 
 159         if (status & BUSY_STAT)
 160                 return 1;
 161         if (status & WRERR_STAT)
 162                 return 0;
 163         if (!(status & READY_STAT))
 164                 return 0;
 165         if (!(status & SEEK_STAT))
 166                 return 0;
 167         return 1;
 168 }
 169 
 170 static int controller_busy(void)
     /*  */
 171 {
 172         int retries = 100000;
 173         unsigned char status;
 174 
 175         do {
 176                 status = inb_p(HD_STATUS);
 177         } while ((status & BUSY_STAT) && --retries);
 178         return status;
 179 }
 180 
 181 static void hd_out(unsigned int drive,unsigned int nsect,unsigned int sect,
     /*  */
 182                 unsigned int head,unsigned int cyl,unsigned int cmd,
 183                 void (*intr_addr)(void))
 184 {
 185         unsigned short port;
 186 
 187         if (drive>1 || head>15)
 188                 panic("Trying to write bad sector");
 189 #if (HD_DELAY > 0)
 190         while (read_timer() - last_req < HD_DELAY)
 191                 /* nothing */;
 192 #endif
 193         if (reset)
 194                 return;
 195         if (!controller_ready(drive, head)) {
 196                 reset = 1;
 197                 return;
 198         }
 199         SET_INTR(intr_addr);
 200         outb_p(hd_info[drive].ctl,HD_CMD);
 201         port=HD_DATA;
 202         outb_p(hd_info[drive].wpcom>>2,++port);
 203         outb_p(nsect,++port);
 204         outb_p(sect,++port);
 205         outb_p(cyl,++port);
 206         outb_p(cyl>>8,++port);
 207         outb_p(0xA0|(drive<<4)|head,++port);
 208         outb_p(cmd,++port);
 209 }
 210 
 211 static int drive_busy(void)
     /*  */
 212 {
 213         unsigned int i;
 214         unsigned char c;
 215 
 216         for (i = 0; i < 500000 ; i++) {
 217                 c = inb_p(HD_STATUS);
 218                 c &= (BUSY_STAT | READY_STAT | SEEK_STAT);
 219                 if (c == (READY_STAT | SEEK_STAT))
 220                         return 0;
 221         }
 222         printk("HD controller times out, status = 0x%02x\n",c);
 223         return 1;
 224 }
 225 
 226 static void reset_controller(void)
     /*  */
 227 {
 228         int     i;
 229 
 230         printk(KERN_DEBUG "HD-controller reset\n");
 231         outb_p(4,HD_CMD);
 232         for(i = 0; i < 1000; i++) nop();
 233         outb(hd_info[0].ctl & 0x0f ,HD_CMD);
 234         if (drive_busy())
 235                 printk("HD-controller still busy\n");
 236         if ((hd_error = inb(HD_ERROR)) != 1)
 237                 printk("HD-controller reset failed: %02x\n",hd_error);
 238 }
 239 
 240 static void reset_hd(void)
     /*  */
 241 {
 242         static int i;
 243 
 244 repeat:
 245         if (reset) {
 246                 reset = 0;
 247                 i = -1;
 248                 reset_controller();
 249         } else if (win_result()) {
 250                 bad_rw_intr();
 251                 if (reset)
 252                         goto repeat;
 253         }
 254         i++;
 255         if (i < NR_HD) {
 256                 hd_out(i,hd_info[i].sect,hd_info[i].sect,hd_info[i].head-1,
 257                         hd_info[i].cyl,WIN_SPECIFY,&reset_hd);
 258                 if (reset)
 259                         goto repeat;
 260         } else
 261                 do_hd_request();
 262 }
 263 
 264 /*
 265  * Ok, don't know what to do with the unexpected interrupts: on some machines
 266  * doing a reset and a retry seems to result in an eternal loop. Right now I
 267  * ignore it, and just set the timeout.
 268  */
 269 void unexpected_hd_interrupt(void)
     /*  */
 270 {
 271         sti();
 272         printk(KERN_DEBUG "Unexpected HD interrupt\n");
 273         SET_TIMER;
 274 }
 275 
 276 /*
 277  * bad_rw_intr() now tries to be a bit smarter and does things
 278  * according to the error returned by the controller.
 279  * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
 280  */
 281 static void bad_rw_intr(void)
     /*  */
 282 {
 283         int dev;
 284 
 285         if (!CURRENT)
 286                 return;
 287         dev = MINOR(CURRENT->dev) >> 6;
 288         if (++CURRENT->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
 289                 end_request(0);
 290                 recalibrate[dev] = 1;
 291         } else if (CURRENT->errors % RESET_FREQ == 0)
 292                 reset = 1;
 293         else if ((hd_error & TRK0_ERR) || CURRENT->errors % RECAL_FREQ == 0)
 294                 recalibrate[dev] = 1;
 295         /* Otherwise just retry */
 296 }
 297 
 298 static inline int wait_DRQ(void)
     /*  */
 299 {
 300         int retries = 100000;
 301 
 302         while (--retries > 0)
 303                 if (inb_p(HD_STATUS) & DRQ_STAT)
 304                         return 0;
 305         return -1;
 306 }
 307 
 308 #define STAT_MASK (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT)
 309 #define STAT_OK (READY_STAT | SEEK_STAT)
 310 
 311 static void read_intr(void)
     /*  */
 312 {
 313         int i;
 314         int retries = 100000;
 315 
 316         do {
 317                 i = (unsigned) inb_p(HD_STATUS);
 318                 if (i & BUSY_STAT)
 319                         continue;
 320                 if ((i & STAT_MASK) != STAT_OK)
 321                         break;
 322                 if (i & DRQ_STAT)
 323                         goto ok_to_read;
 324         } while (--retries > 0);
 325         sti();
 326         printk("HD: read_intr: status = 0x%02x\n",i);
 327         if (i & ERR_STAT) {
 328                 hd_error = (unsigned) inb(HD_ERROR);
 329                 printk("HD: read_intr: error = 0x%02x\n",hd_error);
 330         }
 331         bad_rw_intr();
 332         cli();
 333         do_hd_request();
 334         return;
 335 ok_to_read:
 336         insw(HD_DATA,CURRENT->buffer,256);
 337         CURRENT->errors = 0;
 338         CURRENT->buffer += 512;
 339         CURRENT->sector++;
 340         i = --CURRENT->nr_sectors;
 341         --CURRENT->current_nr_sectors;
 342 #ifdef DEBUG
 343         printk("hd%d : sector = %d, %d remaining to buffer = %08x\n",
 344                 MINOR(CURRENT->dev), CURRENT->sector, i, CURRENT-> 
 345                 buffer);
 346 #endif
 347         if (!i || (CURRENT->bh && !SUBSECTOR(i)))
 348                 end_request(1);
 349         if (i > 0) {
 350                 SET_INTR(&read_intr);
 351                 sti();
 352                 return;
 353         }
 354         (void) inb_p(HD_STATUS);
 355 #if (HD_DELAY > 0)
 356         last_req = read_timer();
 357 #endif
 358         do_hd_request();
 359         return;
 360 }
 361 
 362 static void write_intr(void)
     /*  */
 363 {
 364         int i;
 365         int retries = 100000;
 366 
 367         do {
 368                 i = (unsigned) inb_p(HD_STATUS);
 369                 if (i & BUSY_STAT)
 370                         continue;
 371                 if ((i & STAT_MASK) != STAT_OK)
 372                         break;
 373                 if ((CURRENT->nr_sectors <= 1) || (i & DRQ_STAT))
 374                         goto ok_to_write;
 375         } while (--retries > 0);
 376         sti();
 377         printk("HD: write_intr: status = 0x%02x\n",i);
 378         if (i & ERR_STAT) {
 379                 hd_error = (unsigned) inb(HD_ERROR);
 380                 printk("HD: write_intr: error = 0x%02x\n",hd_error);
 381         }
 382         bad_rw_intr();
 383         cli();
 384         do_hd_request();
 385         return;
 386 ok_to_write:
 387         CURRENT->sector++;
 388         i = --CURRENT->nr_sectors;
 389         --CURRENT->current_nr_sectors;
 390         CURRENT->buffer += 512;
 391         if (!i || (CURRENT->bh && !SUBSECTOR(i)))
 392                 end_request(1);
 393         if (i > 0) {
 394                 SET_INTR(&write_intr);
 395                 outsw(HD_DATA,CURRENT->buffer,256);
 396                 sti();
 397         } else {
 398 #if (HD_DELAY > 0)
 399                 last_req = read_timer();
 400 #endif
 401                 do_hd_request();
 402         }
 403         return;
 404 }
 405 
 406 static void recal_intr(void)
     /*  */
 407 {
 408         if (win_result())
 409                 bad_rw_intr();
 410         do_hd_request();
 411 }
 412 
 413 /*
 414  * This is another of the error-routines I don't know what to do with. The
 415  * best idea seems to just set reset, and start all over again.
 416  */
 417 static void hd_times_out(void)
     /*  */
 418 {
 419         DEVICE_INTR = NULL;
 420         sti();
 421         reset = 1;
 422         if (!CURRENT)
 423                 return;
 424         printk(KERN_DEBUG "HD timeout\n");
 425         cli();
 426         if (++CURRENT->errors >= MAX_ERRORS) {
 427 #ifdef DEBUG
 428                 printk("hd : too many errors.\n");
 429 #endif
 430                 end_request(0);
 431         }
 432 
 433         do_hd_request();
 434 }
 435 
 436 /*
 437  * The driver has been modified to enable interrupts a bit more: in order to
 438  * do this we first (a) disable the timeout-interrupt and (b) clear the
 439  * device-interrupt. This way the interrupts won't mess with out code (the
 440  * worst that can happen is that an unexpected HD-interrupt comes in and
 441  * sets the "reset" variable and starts the timer)
 442  */
 443 static void do_hd_request(void)
     /*  */
 444 {
 445         unsigned int block,dev;
 446         unsigned int sec,head,cyl,track;
 447         unsigned int nsect;
 448 
 449         if (CURRENT && CURRENT->dev < 0) return;
 450 
 451         if (DEVICE_INTR)
 452                 return;
 453 repeat:
 454         timer_active &= ~(1<<HD_TIMER);
 455         sti();
 456         INIT_REQUEST;
 457         dev = MINOR(CURRENT->dev);
 458         block = CURRENT->sector;
 459         nsect = CURRENT->nr_sectors;
 460         if (dev >= (NR_HD<<6) || block >= hd[dev].nr_sects) {
 461 #ifdef DEBUG
 462                 printk("hd%d : attempted read for sector %d past end of device at sector %d.\n",
 463                         block, hd[dev].nr_sects);
 464 #endif
 465                 end_request(0);
 466                 goto repeat;
 467         }
 468         block += hd[dev].start_sect;
 469         dev >>= 6;
 470         sec = block % hd_info[dev].sect + 1;
 471         track = block / hd_info[dev].sect;
 472         head = track % hd_info[dev].head;
 473         cyl = track / hd_info[dev].head;
 474 #ifdef DEBUG
 475         printk("hd%d : cyl = %d, head = %d, sector = %d, buffer = %08x\n",
 476                 dev, cyl, head, sec, CURRENT->buffer);
 477 #endif
 478         cli();
 479         if (reset) {
 480                 int i;
 481 
 482                 for (i=0; i < NR_HD; i++)
 483                         recalibrate[i] = 1;
 484                 reset_hd();
 485                 sti();
 486                 return;
 487         }
 488         if (recalibrate[dev]) {
 489                 recalibrate[dev] = 0;
 490                 hd_out(dev,hd_info[dev].sect,0,0,0,WIN_RESTORE,&recal_intr);
 491                 if (reset)
 492                         goto repeat;
 493                 sti();
 494                 return;
 495         }       
 496         if (CURRENT->cmd == WRITE) {
 497                 hd_out(dev,nsect,sec,head,cyl,WIN_WRITE,&write_intr);
 498                 if (reset)
 499                         goto repeat;
 500                 if (wait_DRQ()) {
 501                         printk("HD: do_hd_request: no DRQ\n");
 502                         bad_rw_intr();
 503                         goto repeat;
 504                 }
 505                 outsw(HD_DATA,CURRENT->buffer,256);
 506                 sti();
 507                 return;
 508         }
 509         if (CURRENT->cmd == READ) {
 510                 hd_out(dev,nsect,sec,head,cyl,WIN_READ,&read_intr);
 511                 if (reset)
 512                         goto repeat;
 513                 sti();
 514                 return;
 515         }
 516         panic("unknown hd-command");
 517 }
 518 
 519 static int hd_ioctl(struct inode * inode, struct file * file,
     /*  */
 520         unsigned int cmd, unsigned long arg)
 521 {
 522         struct hd_geometry *loc = (struct hd_geometry *) arg;
 523         int dev, err;
 524 
 525         if (!inode)
 526                 return -EINVAL;
 527         dev = MINOR(inode->i_rdev) >> 6;
 528         if (dev >= NR_HD)
 529                 return -EINVAL;
 530         switch (cmd) {
 531                 case HDIO_GETGEO:
 532                         if (!loc)  return -EINVAL;
 533                         err = verify_area(VERIFY_WRITE, loc, sizeof(*loc));
 534                         if (err)
 535                                 return err;
 536                         put_fs_byte(hd_info[dev].head,
 537                                 (char *) &loc->heads);
 538                         put_fs_byte(hd_info[dev].sect,
 539                                 (char *) &loc->sectors);
 540                         put_fs_word(hd_info[dev].cyl,
 541                                 (short *) &loc->cylinders);
 542                         put_fs_long(hd[MINOR(inode->i_rdev)].start_sect,
 543                                 (long *) &loc->start);
 544                         return 0;
 545                 case BLKRASET:
 546                         if(!suser())  return -EACCES;
 547                         if(!inode->i_rdev) return -EINVAL;
 548                         if(arg > 0xff) return -EINVAL;
 549                         read_ahead[MAJOR(inode->i_rdev)] = arg;
 550                         return 0;
 551                 case BLKGETSIZE:   /* Return device size */
 552                         if (!arg)  return -EINVAL;
 553                         err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
 554                         if (err)
 555                                 return err;
 556                         put_fs_long(hd[MINOR(inode->i_rdev)].nr_sects,
 557                                 (long *) arg);
 558                         return 0;
 559                 case BLKFLSBUF:
 560                         if(!suser())  return -EACCES;
 561                         if(!inode->i_rdev) return -EINVAL;
 562                         fsync_dev(inode->i_rdev);
 563                         invalidate_buffers(inode->i_rdev);
 564                         return 0;
 565 
 566                 case BLKRRPART: /* Re-read partition tables */
 567                         return revalidate_hddisk(inode->i_rdev, 1);
 568                 RO_IOCTLS(inode->i_rdev,arg);
 569                 default:
 570                         return -EINVAL;
 571         }
 572 }
 573 
 574 static int hd_open(struct inode * inode, struct file * filp)
     /*  */
 575 {
 576         int target;
 577         target =  DEVICE_NR(MINOR(inode->i_rdev));
 578 
 579         while (busy[target])
 580                 sleep_on(&busy_wait);
 581         access_count[target]++;
 582         return 0;
 583 }
 584 
 585 /*
 586  * Releasing a block device means we sync() it, so that it can safely
 587  * be forgotten about...
 588  */
 589 static void hd_release(struct inode * inode, struct file * file)
     /*  */
 590 {
 591         int target;
 592         sync_dev(inode->i_rdev);
 593 
 594         target =  DEVICE_NR(MINOR(inode->i_rdev));
 595         access_count[target]--;
 596 
 597 }
 598 
 599 static void hd_geninit(void);
 600 
 601 static struct gendisk hd_gendisk = {
 602         MAJOR_NR,       /* Major number */      
 603         "hd",           /* Major name */
 604         6,              /* Bits to shift to get real from partition */
 605         1 << 6,         /* Number of partitions per real */
 606         MAX_HD,         /* maximum number of real */
 607         hd_geninit,     /* init function */
 608         hd,             /* hd struct */
 609         hd_sizes,       /* block sizes */
 610         0,              /* number */
 611         (void *) hd_info,       /* internal */
 612         NULL            /* next */
 613 };
 614         
 615 static void hd_interrupt(int unused)
     /*  */
 616 {
 617         void (*handler)(void) = DEVICE_INTR;
 618 
 619         DEVICE_INTR = NULL;
 620         timer_active &= ~(1<<HD_TIMER);
 621         if (!handler)
 622                 handler = unexpected_hd_interrupt;
 623         handler();
 624         sti();
 625 }
 626 
 627 /*
 628  * This is the harddisk IRQ description. The SA_INTERRUPT in sa_flags
 629  * means we run the IRQ-handler with interrupts disabled: this is bad for
 630  * interrupt latency, but anything else has led to problems on some
 631  * machines...
 632  *
 633  * We enable interrupts in some of the routines after making sure it's
 634  * safe.
 635  */
 636 static struct sigaction hd_sigaction = {
 637         hd_interrupt,
 638         0,
 639         SA_INTERRUPT,
 640         NULL
 641 };
 642 
 643 static void hd_geninit(void)
     /*  */
 644 {
 645         int drive, i;
 646         extern struct drive_info drive_info;
 647         unsigned char *BIOS = (unsigned char *) &drive_info;
 648         int cmos_disks;
 649 
 650         if (!NR_HD) {      
 651                 for (drive=0 ; drive<2 ; drive++) {
 652                         hd_info[drive].cyl = *(unsigned short *) BIOS;
 653                         hd_info[drive].head = *(2+BIOS);
 654                         hd_info[drive].wpcom = *(unsigned short *) (5+BIOS);
 655                         hd_info[drive].ctl = *(8+BIOS);
 656                         hd_info[drive].lzone = *(unsigned short *) (12+BIOS);
 657                         hd_info[drive].sect = *(14+BIOS);
 658                         BIOS += 16;
 659                 }
 660 
 661         /*
 662                 We querry CMOS about hard disks : it could be that 
 663                 we have a SCSI/ESDI/etc controller that is BIOS
 664                 compatable with ST-506, and thus showing up in our
 665                 BIOS table, but not register compatable, and therefore
 666                 not present in CMOS.
 667 
 668                 Furthurmore, we will assume that our ST-506 drives
 669                 <if any> are the primary drives in the system, and 
 670                 the ones reflected as drive 1 or 2.
 671 
 672                 The first drive is stored in the high nibble of CMOS
 673                 byte 0x12, the second in the low nibble.  This will be
 674                 either a 4 bit drive type or 0xf indicating use byte 0x19 
 675                 for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.
 676 
 677                 Needless to say, a non-zero value means we have 
 678                 an AT controller hard disk for that drive.
 679 
 680                 
 681         */
 682 
 683                 if ((cmos_disks = CMOS_READ(0x12)) & 0xf0)
 684                         if (cmos_disks & 0x0f)
 685                                 NR_HD = 2;
 686                         else
 687                                 NR_HD = 1;
 688         }
 689         i = NR_HD;
 690         while (i-- > 0) {
 691                 hd[i<<6].nr_sects = 0;
 692                 if (hd_info[i].head > 16) {
 693                         printk("hd.c: ST-506 interface disk with more than 16 heads detected,\n");
 694                         printk("  probably due to non-standard sector translation. Giving up.\n");
 695                         printk("  (disk %d: cyl=%d, sect=%d, head=%d)\n", i,
 696                                 hd_info[i].cyl,
 697                                 hd_info[i].sect,
 698                                 hd_info[i].head);
 699                         if (i+1 == NR_HD)
 700                                 NR_HD--;
 701                         continue;
 702                 }
 703                 hd[i<<6].nr_sects = hd_info[i].head*
 704                                 hd_info[i].sect*hd_info[i].cyl;
 705         }
 706         if (NR_HD) {
 707                 if (irqaction(HD_IRQ,&hd_sigaction)) {
 708                         printk("hd.c: unable to get IRQ%d for the harddisk driver\n",HD_IRQ);
 709                         NR_HD = 0;
 710                 }
 711         }
 712         hd_gendisk.nr_real = NR_HD;
 713 
 714         for(i=0;i<(MAX_HD << 6);i++) hd_blocksizes[i] = 1024;
 715         blksize_size[MAJOR_NR] = hd_blocksizes;
 716 }
 717 
 718 static struct file_operations hd_fops = {
 719         NULL,                   /* lseek - default */
 720         block_read,             /* read - general block-dev read */
 721         block_write,            /* write - general block-dev write */
 722         NULL,                   /* readdir - bad */
 723         NULL,                   /* select */
 724         hd_ioctl,               /* ioctl */
 725         NULL,                   /* mmap */
 726         hd_open,                /* open */
 727         hd_release,             /* release */
 728         block_fsync             /* fsync */
 729 };
 730 
 731 unsigned long hd_init(unsigned long mem_start, unsigned long mem_end)
     /*  */
 732 {
 733         if (register_blkdev(MAJOR_NR,"hd",&hd_fops)) {
 734                 printk("Unable to get major %d for harddisk\n",MAJOR_NR);
 735                 return mem_start;
 736         }
 737         blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
 738         read_ahead[MAJOR_NR] = 8;               /* 8 sector (4kB) read-ahead */
 739         hd_gendisk.next = gendisk_head;
 740         gendisk_head = &hd_gendisk;
 741         timer_table[HD_TIMER].fn = hd_times_out;
 742         return mem_start;
 743 }
 744 
 745 #define DEVICE_BUSY busy[target]
 746 #define USAGE access_count[target]
 747 #define CAPACITY (hd_info[target].head*hd_info[target].sect*hd_info[target].cyl)
 748 /* We assume that the the bios parameters do not change, so the disk capacity
 749    will not change */
 750 #undef MAYBE_REINIT
 751 #define GENDISK_STRUCT hd_gendisk
 752 
 753 /*
 754  * This routine is called to flush all partitions and partition tables
 755  * for a changed scsi disk, and then re-read the new partition table.
 756  * If we are revalidating a disk because of a media change, then we
 757  * enter with usage == 0.  If we are using an ioctl, we automatically have
 758  * usage == 1 (we need an open channel to use an ioctl :-), so this
 759  * is our limit.
 760  */
 761 static int revalidate_hddisk(int dev, int maxusage)
     /*  */
 762 {
 763         int target, major;
 764         struct gendisk * gdev;
 765         int max_p;
 766         int start;
 767         int i;
 768 
 769         target =  DEVICE_NR(MINOR(dev));
 770         gdev = &GENDISK_STRUCT;
 771 
 772         cli();
 773         if (DEVICE_BUSY || USAGE > maxusage) {
 774                 sti();
 775                 return -EBUSY;
 776         };
 777         DEVICE_BUSY = 1;
 778         sti();
 779 
 780         max_p = gdev->max_p;
 781         start = target << gdev->minor_shift;
 782         major = MAJOR_NR << 8;
 783 
 784         for (i=max_p - 1; i >=0 ; i--) {
 785                 sync_dev(major | start | i);
 786                 invalidate_inodes(major | start | i);
 787                 invalidate_buffers(major | start | i);
 788                 gdev->part[start+i].start_sect = 0;
 789                 gdev->part[start+i].nr_sects = 0;
 790         };
 791 
 792 #ifdef MAYBE_REINIT
 793         MAYBE_REINIT;
 794 #endif
 795 
 796         gdev->part[start].nr_sects = CAPACITY;
 797         resetup_one_dev(gdev, target);
 798 
 799         DEVICE_BUSY = 0;
 800         wake_up(&busy_wait);
 801         return 0;
 802 }
 803
/* */
root/drivers/block/hd.c

DEFINITIONS
