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/*
* linux/drivers/ide/ide-geometry.c
*/
#include <linux/config.h>
#include <linux/ide.h>
#include <linux/mc146818rtc.h>
#include <asm/io.h>
/*
* We query CMOS about hard disks : it could be that we have a SCSI/ESDI/etc
* controller that is BIOS compatible with ST-506, and thus showing up in our
* BIOS table, but not register compatible, and therefore not present in CMOS.
*
* Furthermore, we will assume that our ST-506 drives <if any> are the primary
* drives in the system -- the ones reflected as drive 1 or 2. The first
* drive is stored in the high nibble of CMOS byte 0x12, the second in the low
* nibble. This will be either a 4 bit drive type or 0xf indicating use byte
* 0x19 for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS. A non-zero value
* means we have an AT controller hard disk for that drive.
*
* Of course, there is no guarantee that either drive is actually on the
* "primary" IDE interface, but we don't bother trying to sort that out here.
* If a drive is not actually on the primary interface, then these parameters
* will be ignored. This results in the user having to supply the logical
* drive geometry as a boot parameter for each drive not on the primary i/f.
*/
/*
* The only "perfect" way to handle this would be to modify the setup.[cS] code
* to do BIOS calls Int13h/Fn08h and Int13h/Fn48h to get all of the drive info
* for us during initialization. I have the necessary docs -- any takers? -ml
*/
/*
* I did this, but it doesnt work - there is no reasonable way to find the
* correspondence between the BIOS numbering of the disks and the Linux
* numbering. -aeb
*
* The code below is bad. One of the problems is that drives 1 and 2
* may be SCSI disks (even when IDE disks are present), so that
* the geometry we read here from BIOS is attributed to the wrong disks.
* Consequently, also the former "drive->present = 1" below was a mistake.
*
* Eventually the entire routine below should be removed.
*/
void probe_cmos_for_drives (ide_hwif_t *hwif)
{
#ifdef __i386__
extern struct drive_info_struct drive_info;
byte cmos_disks, *BIOS = (byte *) &drive_info;
int unit;
unsigned long flags;
#ifdef CONFIG_BLK_DEV_PDC4030
if (hwif->chipset == ide_pdc4030 && hwif->channel != 0)
return;
#endif /* CONFIG_BLK_DEV_PDC4030 */
spin_lock_irqsave(&rtc_lock, flags);
cmos_disks = CMOS_READ(0x12);
spin_unlock_irqrestore(&rtc_lock, flags);
/* Extract drive geometry from CMOS+BIOS if not already setup */
for (unit = 0; unit < MAX_DRIVES; ++unit) {
ide_drive_t *drive = &hwif->drives[unit];
if ((cmos_disks & (0xf0 >> (unit*4)))
&& !drive->present && !drive->nobios) {
unsigned short cyl = *(unsigned short *)BIOS;
unsigned char head = *(BIOS+2);
unsigned char sect = *(BIOS+14);
if (cyl > 0 && head > 0 && sect > 0 && sect < 64) {
drive->cyl = drive->bios_cyl = cyl;
drive->head = drive->bios_head = head;
drive->sect = drive->bios_sect = sect;
drive->ctl = *(BIOS+8);
} else {
printk("hd%c: C/H/S=%d/%d/%d from BIOS ignored\n",
unit+'a', cyl, head, sect);
}
}
BIOS += 16;
}
#endif
}
#ifdef CONFIG_BLK_DEV_IDE
extern ide_drive_t * get_info_ptr(kdev_t);
extern unsigned long current_capacity (ide_drive_t *);
/*
* If heads is nonzero: find a translation with this many heads and S=63.
* Otherwise: find out how OnTrack Disk Manager would translate the disk.
*/
static void
ontrack(ide_drive_t *drive, int heads, unsigned int *c, int *h, int *s) {
static const byte dm_head_vals[] = {4, 8, 16, 32, 64, 128, 255, 0};
const byte *headp = dm_head_vals;
unsigned long total;
/*
* The specs say: take geometry as obtained from Identify,
* compute total capacity C*H*S from that, and truncate to
* 1024*255*63. Now take S=63, H the first in the sequence
* 4, 8, 16, 32, 64, 128, 255 such that 63*H*1024 >= total.
* [Please tell aeb@cwi.nl in case this computes a
* geometry different from what OnTrack uses.]
*/
total = DRIVER(drive)->capacity(drive);
*s = 63;
if (heads) {
*h = heads;
*c = total / (63 * heads);
return;
}
while (63 * headp[0] * 1024 < total && headp[1] != 0)
headp++;
*h = headp[0];
*c = total / (63 * headp[0]);
}
/*
* This routine is called from the partition-table code in pt/msdos.c.
* It has two tasks:
* (i) to handle Ontrack DiskManager by offsetting everything by 63 sectors,
* or to handle EZdrive by remapping sector 0 to sector 1.
* (ii) to invent a translated geometry.
* Part (i) is suppressed if the user specifies the "noremap" option
* on the command line.
* Part (ii) is suppressed if the user specifies an explicit geometry.
*
* The ptheads parameter is either 0 or tells about the number of
* heads shown by the end of the first nonempty partition.
* If this is either 16, 32, 64, 128, 240 or 255 we'll believe it.
*
* The xparm parameter has the following meaning:
* 0 = convert to CHS with fewer than 1024 cyls
* using the same method as Ontrack DiskManager.
* 1 = same as "0", plus offset everything by 63 sectors.
* -1 = similar to "0", plus redirect sector 0 to sector 1.
* 2 = convert to a CHS geometry with "ptheads" heads.
*
* Returns 0 if the translation was not possible, if the device was not
* an IDE disk drive, or if a geometry was "forced" on the commandline.
* Returns 1 if the geometry translation was successful.
*/
int ide_xlate_1024 (kdev_t i_rdev, int xparm, int ptheads, const char *msg)
{
ide_drive_t *drive;
const char *msg1 = "";
int heads = 0;
int c, h, s;
int transl = 1; /* try translation */
int ret = 0;
drive = get_info_ptr(i_rdev);
if (!drive)
return 0;
/* remap? */
if (drive->remap_0_to_1 != 2) {
if (xparm == 1) { /* DM */
drive->sect0 = 63;
msg1 = " [remap +63]";
ret = 1;
} else if (xparm == -1) { /* EZ-Drive */
if (drive->remap_0_to_1 == 0) {
drive->remap_0_to_1 = 1;
msg1 = " [remap 0->1]";
ret = 1;
}
}
}
/* There used to be code here that assigned drive->id->CHS
to drive->CHS and that to drive->bios_CHS. However,
some disks have id->C/H/S = 4092/16/63 but are larger than 2.1 GB.
In such cases that code was wrong. Moreover,
there seems to be no reason to do any of these things. */
/* translate? */
if (drive->forced_geom)
transl = 0;
/* does ptheads look reasonable? */
if (ptheads == 32 || ptheads == 64 || ptheads == 128 ||
ptheads == 240 || ptheads == 255)
heads = ptheads;
if (xparm == 2) {
if (!heads ||
(drive->bios_head >= heads && drive->bios_sect == 63))
transl = 0;
}
if (xparm == -1) {
if (drive->bios_head > 16)
transl = 0; /* we already have a translation */
}
if (transl) {
ontrack(drive, heads, &c, &h, &s);
drive->bios_cyl = c;
drive->bios_head = h;
drive->bios_sect = s;
ret = 1;
}
drive->part[0].nr_sects = current_capacity(drive);
if (ret)
printk("%s%s [%d/%d/%d]", msg, msg1,
drive->bios_cyl, drive->bios_head, drive->bios_sect);
return ret;
}
#endif /* CONFIG_BLK_DEV_IDE */
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