patch-2.3.21 linux/drivers/block/ide-geometry.c

• Lines: 226
• Date: Mon Oct 11 10:06:34 1999
• Orig file: v2.3.20/linux/drivers/block/ide-geometry.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.20/linux/drivers/block/ide-geometry.c linux/drivers/block/ide-geometry.c
@@ -0,0 +1,225 @@
+/*
+ * linux/drivers/block/ide-geometry.c
+ */
+#include <linux/ide.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 "drive->present = 1" below is 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;
+
+#ifdef CONFIG_BLK_DEV_PDC4030
+	if (hwif->chipset == ide_pdc4030 && hwif->channel != 0)
+		return;
+#endif /* CONFIG_BLK_DEV_PDC4030 */
+	outb_p(0x12,0x70);		/* specify CMOS address 0x12 */
+	cmos_disks = inb_p(0x71);	/* read the data from 0x12 */
+	/* 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) {
+			drive->cyl   = drive->bios_cyl  = *(unsigned short *)BIOS;
+			drive->head  = drive->bios_head = *(BIOS+2);
+			drive->sect  = drive->bios_sect = *(BIOS+14);
+			drive->ctl   = *(BIOS+8);
+#if 0
+			drive->present = 1;
+#endif
+		}
+		BIOS += 16;
+	}
+#endif
+}
+
+
+/*
+ * 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, int *c, int *h, int *s) {
+	struct hd_driveid *id = drive->id;
+	static const byte dm_head_vals[] = {4, 8, 16, 32, 64, 128, 255, 0};
+	const byte *headp = dm_head_vals;
+	unsigned long total, tracks;
+
+	/*
+	 * 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.
+	 */
+	if (id)
+		total = id->cyls * id->heads * id->sectors;
+	else
+		total = drive->cyl * drive->head * drive->sect;
+
+	*s = 63;
+
+	if (heads) {
+		*h = heads;
+		*c = total / (63 * heads);
+		return;
+	}
+
+#if 0
+	while (63 * headp[0] * 1024 < total && headp[1] != 0)
+		 headp++;
+	*h = headp[0];
+	*c = total / (63 * headp[0]);
+#else
+	/* The code below differs in two aspects:
+	   (i) It will not produce geometries like C/H/S = 1024/64/63
+		because of the `>='. This follows OnTracks text (which
+		claims that 512 <= C <= 1023), but not OnTracks code.
+	   (ii) It starts dividing by 63, so that a rounding down occurs.
+		For example, with C=11159, H=10, S=37 we find total=4128830
+		and DM would make C=512, H=128, S=63, but we make 1024/64/63
+		if `>=' is replaced by `>'.
+	   The reason we use this code is mainly that we have done so for
+	   a long time without getting complaints.
+	*/
+
+	tracks = total / 63;
+	while (*c >= 1024) {
+		*h = *headp;
+		*c = tracks / *h;
+		if (*++headp == 0)
+			break;
+	}
+#endif
+}
+
+/*
+ * 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;
+}