drivers/ide/ide-geometry.c

   1 /*
   2  * linux/drivers/block/ide-geometry.c
   3  */
   4 #include <linux/config.h>
   5
   6 #ifdef CONFIG_BLK_DEV_IDE
   7 #include <linux/ide.h>
   8
   9 #include <asm/io.h>
  10
  11 extern ide_drive_t * get_info_ptr(kdev_t);
  12 extern unsigned long current_capacity (ide_drive_t *);
  13
  14 /*
  15  * We query CMOS about hard disks : it could be that we have a SCSI/ESDI/etc
  16  * controller that is BIOS compatible with ST-506, and thus showing up in our
  17  * BIOS table, but not register compatible, and therefore not present in CMOS.
  18  *
  19  * Furthermore, we will assume that our ST-506 drives <if any> are the primary
  20  * drives in the system -- the ones reflected as drive 1 or 2.  The first
  21  * drive is stored in the high nibble of CMOS byte 0x12, the second in the low
  22  * nibble.  This will be either a 4 bit drive type or 0xf indicating use byte
  23  * 0x19 for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.  A non-zero value
  24  * means we have an AT controller hard disk for that drive.
  25  *
  26  * Of course, there is no guarantee that either drive is actually on the
  27  * "primary" IDE interface, but we don't bother trying to sort that out here.
  28  * If a drive is not actually on the primary interface, then these parameters
  29  * will be ignored.  This results in the user having to supply the logical
  30  * drive geometry as a boot parameter for each drive not on the primary i/f.
  31  */
  32 /*
  33  * The only "perfect" way to handle this would be to modify the setup.[cS] code
  34  * to do BIOS calls Int13h/Fn08h and Int13h/Fn48h to get all of the drive info
  35  * for us during initialization.  I have the necessary docs -- any takers?  -ml
  36  */
  37 /*
  38  * I did this, but it doesnt work - there is no reasonable way to find the
  39  * correspondence between the BIOS numbering of the disks and the Linux
  40  * numbering. -aeb
  41  *
  42  * The code below is bad. One of the problems is that drives 1 and 2
  43  * may be SCSI disks (even when IDE disks are present), so that
  44  * the geometry we read here from BIOS is attributed to the wrong disks.
  45  * Consequently, also the "drive->present = 1" below is a mistake.
  46  *
  47  * Eventually the entire routine below should be removed.
  48  */
  49 void probe_cmos_for_drives (ide_hwif_t *hwif)
  50 {
  51 #ifdef __i386__
  52         extern struct drive_info_struct drive_info;
  53         byte cmos_disks, *BIOS = (byte *) &drive_info;
  54         int unit;
  55
  56 #ifdef CONFIG_BLK_DEV_PDC4030
  57         if (hwif->chipset == ide_pdc4030 && hwif->channel != 0)
  58                 return;
  59 #endif /* CONFIG_BLK_DEV_PDC4030 */
  60         outb_p(0x12,0x70);              /* specify CMOS address 0x12 */
  61         cmos_disks = inb_p(0x71);       /* read the data from 0x12 */
  62         /* Extract drive geometry from CMOS+BIOS if not already setup */
  63         for (unit = 0; unit < MAX_DRIVES; ++unit) {
  64                 ide_drive_t *drive = &hwif->drives[unit];
  65
  66                 if ((cmos_disks & (0xf0 >> (unit*4)))
  67                    && !drive->present && !drive->nobios) {
  68                         unsigned short cyl = *(unsigned short *)BIOS;
  69                         unsigned char head = *(BIOS+2);
  70                         unsigned char sect = *(BIOS+14);
  71                         if (cyl > 0 && head > 0 && sect > 0 && sect < 64) {
  72                                 drive->cyl   = drive->bios_cyl  = cyl;
  73                                 drive->head  = drive->bios_head = head;
  74                                 drive->sect  = drive->bios_sect = sect;
  75                                 drive->ctl   = *(BIOS+8);
  76                         } else {
  77                                 printk("hd%d: C/H/S=%d/%d/%d from BIOS ignored\n", unit, cyl, head, sect);
  78                         }
  79                 }
  80
  81                 BIOS += 16;
  82         }
  83 #endif
  84 }
  85
  86
  87 /*
  88  * If heads is nonzero: find a translation with this many heads and S=63.
  89  * Otherwise: find out how OnTrack Disk Manager would translate the disk.
  90  */
  91 static void
  92 ontrack(ide_drive_t *drive, int heads, unsigned int *c, int *h, int *s) {
  93         static const byte dm_head_vals[] = {4, 8, 16, 32, 64, 128, 255, 0};
  94         const byte *headp = dm_head_vals;
  95         unsigned long total;
  96
  97         /*
  98          * The specs say: take geometry as obtained from Identify,
  99          * compute total capacity C*H*S from that, and truncate to
 100          * 1024*255*63. Now take S=63, H the first in the sequence
 101          * 4, 8, 16, 32, 64, 128, 255 such that 63*H*1024 >= total.
 102          * [Please tell aeb@cwi.nl in case this computes a
 103          * geometry different from what OnTrack uses.]
 104          */
 105         total = DRIVER(drive)->capacity(drive);
 106
 107         *s = 63;
 108
 109         if (heads) {
 110                 *h = heads;
 111                 *c = total / (63 * heads);
 112                 return;
 113         }
 114
 115         while (63 * headp[0] * 1024 < total && headp[1] != 0)
 116                  headp++;
 117         *h = headp[0];
 118         *c = total / (63 * headp[0]);
 119 }
 120
 121 /*
 122  * This routine is called from the partition-table code in pt/msdos.c.
 123  * It has two tasks:
 124  * (i) to handle Ontrack DiskManager by offsetting everything by 63 sectors,
 125  *  or to handle EZdrive by remapping sector 0 to sector 1.
 126  * (ii) to invent a translated geometry.
 127  * Part (i) is suppressed if the user specifies the "noremap" option
 128  * on the command line.
 129  * Part (ii) is suppressed if the user specifies an explicit geometry.
 130  *
 131  * The ptheads parameter is either 0 or tells about the number of
 132  * heads shown by the end of the first nonempty partition.
 133  * If this is either 16, 32, 64, 128, 240 or 255 we'll believe it.
 134  *
 135  * The xparm parameter has the following meaning:
 136  *       0 = convert to CHS with fewer than 1024 cyls
 137  *           using the same method as Ontrack DiskManager.
 138  *       1 = same as "0", plus offset everything by 63 sectors.
 139  *      -1 = similar to "0", plus redirect sector 0 to sector 1.
 140  *       2 = convert to a CHS geometry with "ptheads" heads.
 141  *
 142  * Returns 0 if the translation was not possible, if the device was not
 143  * an IDE disk drive, or if a geometry was "forced" on the commandline.
 144  * Returns 1 if the geometry translation was successful.
 145  */
 146 int ide_xlate_1024 (kdev_t i_rdev, int xparm, int ptheads, const char *msg)
 147 {
 148         ide_drive_t *drive;
 149         const char *msg1 = "";
 150         int heads = 0;
 151         int c, h, s;
 152         int transl = 1;         /* try translation */
 153         int ret = 0;
 154
 155         drive = get_info_ptr(i_rdev);
 156         if (!drive)
 157                 return 0;
 158
 159         /* remap? */
 160         if (drive->remap_0_to_1 != 2) {
 161                 if (xparm == 1) {               /* DM */
 162                         drive->sect0 = 63;
 163                         msg1 = " [remap +63]";
 164                         ret = 1;
 165                 } else if (xparm == -1) {       /* EZ-Drive */
 166                         if (drive->remap_0_to_1 == 0) {
 167                                 drive->remap_0_to_1 = 1;
 168                                 msg1 = " [remap 0->1]";
 169                                 ret = 1;
 170                         }
 171                 }
 172         }
 173
 174         /* There used to be code here that assigned drive->id->CHS
 175            to drive->CHS and that to drive->bios_CHS. However,
 176            some disks have id->C/H/S = 4092/16/63 but are larger than 2.1 GB.
 177            In such cases that code was wrong.  Moreover,
 178            there seems to be no reason to do any of these things. */
 179
 180         /* translate? */
 181         if (drive->forced_geom)
 182                 transl = 0;
 183
 184         /* does ptheads look reasonable? */
 185         if (ptheads == 32 || ptheads == 64 || ptheads == 128 ||
 186             ptheads == 240 || ptheads == 255)
 187                 heads = ptheads;
 188
 189         if (xparm == 2) {
 190                 if (!heads ||
 191                    (drive->bios_head >= heads && drive->bios_sect == 63))
 192                         transl = 0;
 193         }
 194         if (xparm == -1) {
 195                 if (drive->bios_head > 16)
 196                         transl = 0;     /* we already have a translation */
 197         }
 198
 199         if (transl) {
 200                 ontrack(drive, heads, &c, &h, &s);
 201                 drive->bios_cyl = c;
 202                 drive->bios_head = h;
 203                 drive->bios_sect = s;
 204                 ret = 1;
 205         }
 206
 207         drive->part[0].nr_sects = current_capacity(drive);
 208
 209         if (ret)
 210                 printk("%s%s [%d/%d/%d]", msg, msg1,
 211                        drive->bios_cyl, drive->bios_head, drive->bios_sect);
 212         return ret;
 213 }
 214 #endif /* CONFIG_BLK_DEV_IDE */