146 lines
4.3 KiB
C
146 lines
4.3 KiB
C
/* $NetBSD: biosdisk_ll.c,v 1.3 1997/06/13 13:36:06 drochner Exp $ */
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/*
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* Copyright (c) 1996
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* Matthias Drochner. All rights reserved.
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* Copyright (c) 1996
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* Perry E. Metzger. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgements:
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* This product includes software developed for the NetBSD Project
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* by Matthias Drochner.
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* This product includes software developed for the NetBSD Project
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* by Perry E. Metzger.
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* 4. The names of the authors may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* shared by bootsector startup (bootsectmain) and biosdisk.c
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* needs lowlevel parts from bios_disk.S
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*/
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#include <lib/libsa/stand.h>
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#include "biosdisk_ll.h"
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#include "diskbuf.h"
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extern int get_diskinfo __P((int));
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extern int biosread __P((int, int, int, int, int, char *));
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#define SPT(di) ((di)&0xff)
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#define HEADS(di) ((((di)>>8)&0xff)+1)
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int
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set_geometry(d)
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struct biosdisk_ll *d;
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{
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int diskinfo;
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diskinfo = get_diskinfo(d->dev);
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d->spc = (d->spt = SPT(diskinfo)) * HEADS(diskinfo);
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/*
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* get_diskinfo assumes floppy if BIOS call fails. Check at least
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* "valid" geometry.
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*/
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return (!d->spc || !d->spt);
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}
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/*
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* Global shared "diskbuf" is used as read ahead buffer. For reading from
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* floppies, the bootstrap has to be loaded on a 64K boundary to ensure that
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* this buffer doesn't cross a 64K DMA boundary.
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*/
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#define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE)
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static int ra_dev;
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static int ra_end;
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static int ra_first;
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int
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readsects(d, dblk, num, buf, cold) /* reads ahead if (!cold) */
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struct biosdisk_ll *d;
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int dblk, num;
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char *buf;
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int cold; /* don't use data segment or bss, don't call
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* library functions */
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{
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while (num) {
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int nsec;
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/* check for usable data in read-ahead buffer */
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if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev
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|| dblk < ra_first || dblk >= ra_end) {
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/* no, read from disk */
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int cyl, head, sec;
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char *trbuf;
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cyl = dblk / d->spc;
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head = (dblk % d->spc) / d->spt;
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sec = dblk % d->spt;
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nsec = d->spt - sec;
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if (cold) {
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/* transfer directly to buffer */
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trbuf = buf;
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if (nsec > num)
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nsec = num;
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} else {
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/* fill read-ahead buffer */
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trbuf = diskbuf;
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if (nsec > RA_SECTORS)
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nsec = RA_SECTORS;
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ra_dev = d->dev;
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ra_first = dblk;
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ra_end = dblk + nsec;
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diskbuf_user = &ra_dev;
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}
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if (biosread(d->dev, cyl, head, sec, nsec, trbuf)) {
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if (!cold)
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diskbuf_user = 0; /* mark invalid */
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return (-1); /* XXX cannot output here if
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* (cold) */
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}
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} else /* can take blocks from end of read-ahead
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* buffer */
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nsec = ra_end - dblk;
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if (!cold) {
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/* copy data from read-ahead to user buffer */
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if (nsec > num)
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nsec = num;
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bcopy(diskbuf + (dblk - ra_first) * BIOSDISK_SECSIZE,
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buf, nsec * BIOSDISK_SECSIZE);
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}
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buf += nsec * BIOSDISK_SECSIZE;
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num -= nsec;
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dblk += nsec;
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}
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return (0);
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}
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