diff options
Diffstat (limited to 'sys/i386/boot/dosboot/disk.c')
| -rw-r--r-- | sys/i386/boot/dosboot/disk.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/sys/i386/boot/dosboot/disk.c b/sys/i386/boot/dosboot/disk.c new file mode 100644 index 0000000..263d3e9 --- /dev/null +++ b/sys/i386/boot/dosboot/disk.c @@ -0,0 +1,295 @@ +/*
+ * Mach Operating System
+ * Copyright (c) 1992, 1991 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
+ * School of Computer Science
+ * Carnegie Mellon University
+ * Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ *
+ * from: Mach, Revision 2.2 92/04/04 11:35:49 rpd
+ * $Id: disk.c,v 1.4 1994/02/22 22:59:40 rgrimes Exp $
+ */
+#include <stdio.h>
+#include <memory.h>
+
+#define bcopy(a,b,c) memcpy(b,a,c)
+
+#include "boot.h"
+#ifdef DO_BAD144
+#include "dkbad.h"
+#endif
+#include "disklabe.h"
+
+#define BIOS_DEV_FLOPPY 0x0
+#define BIOS_DEV_WIN 0x80
+
+#define BPS 512
+#define SPT(di) ((di)&0xff)
+#define HEADS(di) ((((di)>>8)&0xff)+1)
+
+static char i_buf[BPS];
+#define I_ADDR ((void *) i_buf) /* XXX where all reads go */
+
+#ifdef DO_BAD144
+struct dkbad dkb;
+int do_bad144;
+long bsize;
+#endif
+
+static int spt, spc;
+
+char *iodest;
+struct fs *fs;
+struct inode inode;
+long dosdev, slice, unit, part, maj, boff, poff, bnum, cnt;
+
+extern int biosread(int dev, int track, int head, int sector, int cnt, unsigned char far *buffer);
+
+/*#define EMBEDDED_DISKLABEL 1*/
+/*extern struct disklabel disklabel;*/
+struct disklabel disklabel;
+
+static void Bread(int dosdev, long sector);
+static long badsect(int dosdev, long sector);
+
+unsigned long get_diskinfo(int drive)
+{
+ char dr = (char) drive;
+ unsigned long rt;
+
+ _asm {
+ mov ah,8 ; get diskinfo
+ mov dl,dr ; drive
+ int 13h
+ cmp ah,0
+ je ok
+ ;
+ ; Failure! We assume it's a floppy!
+ ;
+ sub ax,ax
+ mov bh,ah
+ mov bl,2
+ mov ch,79
+ mov cl,15
+ mov dh,1
+ mov dl,1
+ ok:
+ mov ah,dh
+ mov al,cl
+ and al,3fh
+ mov word ptr rt,ax
+
+ xor bx,bx
+ mov bl,cl
+ and bl,0c0h
+ shl bx,2
+ mov bl,ch
+ mov word ptr rt+2,bx
+ }
+ return rt;
+}
+
+int devopen(void)
+{
+ struct dos_partition *dptr;
+ struct disklabel *dl;
+ int dosdev = (int) inode.i_dev;
+ int i;
+ long di, sector;
+
+ di = get_diskinfo(dosdev);
+ spc = (spt = (int)SPT(di)) * (int)HEADS(di);
+ if (dosdev == 2)
+ {
+ boff = 0;
+ part = (spt == 15 ? 3 : 1);
+ }
+ else
+ {
+#ifdef EMBEDDED_DISKLABEL
+ dl = &disklabel;
+#else EMBEDDED_DISKLABEL
+ Bread(dosdev, 0);
+ dptr = (struct dos_partition *)(((char *)I_ADDR)+DOSPARTOFF);
+ sector = LABELSECTOR;
+ for (i = 0; i < NDOSPART; i++, dptr++)
+ if (dptr->dp_typ == DOSPTYP_386BSD) {
+ sector = dptr->dp_start + LABELSECTOR;
+ slice = i+1;
+ break;
+ }
+ Bread(dosdev, sector++);
+ dl=((struct disklabel *)I_ADDR);
+ disklabel = *dl; /* structure copy (maybe useful later)*/
+#endif EMBEDDED_DISKLABEL
+ if (dl->d_magic != DISKMAGIC) {
+ printf("bad disklabel");
+ return 1;
+ }
+
+ if( (maj == 4) || (maj == 0) || (maj == 1)) {
+ if (dl->d_type == DTYPE_SCSI)
+ maj = 4; /* use scsi as boot dev */
+ else
+ maj = 0; /* must be ESDI/IDE */
+ }
+
+ boff = dl->d_partitions[part].p_offset;
+#ifdef DO_BAD144
+ bsize = dl->d_partitions[part].p_size;
+ do_bad144 = 0;
+ if (dl->d_flags & D_BADSECT) {
+ /* this disk uses bad144 */
+ int i;
+ long dkbbnum;
+ struct dkbad *dkbptr;
+
+ /* find the first readable bad144 sector */
+ /* some of this code is copied from ufs/disk_subr.c */
+ /* read a bad sector table */
+ dkbbnum = dl->d_secperunit - dl->d_nsectors;
+ if (dl->d_secsize > DEV_BSIZE)
+ dkbbnum *= dl->d_secsize / DEV_BSIZE;
+ else
+ dkbbnum /= DEV_BSIZE / dl->d_secsize;
+ i = 0;
+ do_bad144 = 0;
+ do {
+ /* XXX: what if the "DOS sector" < 512 bytes ??? */
+ Bread(dosdev, dkbbnum + i);
+ dkbptr = (struct dkbad *) I_ADDR;
+/* XXX why is this not in <sys/dkbad.h> ??? */
+#define DKBAD_MAGIC 0x4321
+ if (dkbptr->bt_mbz == 0 &&
+ dkbptr->bt_flag == DKBAD_MAGIC) {
+ dkb = *dkbptr; /* structure copy */
+ do_bad144 = 1;
+ break;
+ }
+ i += 2;
+ } while (i < 10 && (u_long) i < dl->d_nsectors);
+ if (!do_bad144)
+ printf("Bad badsect table\n");
+ else
+ printf("Using bad144 bad sector at %ld\n", dkbbnum+i);
+ }
+#endif
+ }
+ return 0;
+}
+
+void devread(void)
+{
+ long offset, sector = bnum;
+ int dosdev = (int) inode.i_dev;
+ for (offset = 0; offset < cnt; offset += BPS)
+ {
+ Bread(dosdev, badsect(dosdev, sector++));
+ bcopy(I_ADDR, iodest+offset, BPS);
+ }
+}
+
+/* Read ahead buffer large enough for one track on a 1440K floppy. For
+ * reading from floppies, the bootstrap has to be loaded on a 64K boundary
+ * to ensure that this buffer doesn't cross a 64K DMA boundary.
+ */
+#define RA_SECTORS 18
+static char ra_buf[RA_SECTORS * BPS];
+static int ra_dev;
+static long ra_end;
+static long ra_first;
+
+static void Bread(int dosdev, long sector)
+{
+ if (dosdev != ra_dev || sector < ra_first || sector >= ra_end)
+ {
+ int cyl, head, sec, nsec;
+
+ cyl = (int) (sector/(long)spc);
+ head = (int) ((sector % (long) spc) / (long) spt);
+ sec = (int) (sector % (long) spt);
+ nsec = spt - sec;
+ if (nsec > RA_SECTORS)
+ nsec = RA_SECTORS;
+ if (biosread(dosdev, cyl, head, sec, nsec, ra_buf) != 0)
+ {
+ nsec = 1;
+ while (biosread(dosdev, cyl, head, sec, nsec, ra_buf) != 0)
+ printf("Error: C:%d H:%d S:%d\n", cyl, head, sec);
+ }
+ ra_dev = dosdev;
+ ra_first = sector;
+ ra_end = sector + nsec;
+ }
+ bcopy(ra_buf + (sector - ra_first) * BPS, I_ADDR, BPS);
+}
+
+static long badsect(int dosdev, long sector)
+{
+#ifdef DO_BAD144
+ int i;
+
+ if (do_bad144) {
+ u_short cyl;
+ u_short head;
+ u_short sec;
+ long newsec;
+ struct disklabel *dl = &disklabel;
+
+ /* XXX */
+ /* from wd.c */
+ /* bt_cyl = cylinder number in sorted order */
+ /* bt_trksec is actually (head << 8) + sec */
+
+ /* only remap sectors in the partition */
+ if (sector < boff || sector >= boff + bsize) {
+ goto no_remap;
+ }
+
+ cyl = (u_short) (sector / dl->d_secpercyl);
+ head = (u_short) ((sector % dl->d_secpercyl) / dl->d_nsectors);
+ sec = (u_short) (sector % dl->d_nsectors);
+ sec = (head<<8) + sec;
+
+ /* now, look in the table for a possible bad sector */
+ for (i=0; i<126; i++) {
+ if (dkb.bt_bad[i].bt_cyl == cyl) {
+ /* found same cylinder */
+ if (dkb.bt_bad[i].bt_trksec == sec) {
+ /* FOUND! */
+ break;
+ }
+ } else if (dkb.bt_bad[i].bt_cyl > cyl) {
+ i = 126;
+ break;
+ }
+ }
+ if (i == 126) {
+ /* didn't find bad sector */
+ goto no_remap;
+ }
+ /* otherwise find replacement sector */
+ newsec = dl->d_secperunit - dl->d_nsectors - i -1;
+ return newsec;
+ }
+ no_remap:
+#endif
+ return sector;
+}
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