NetBSD/sys/arch/i386/stand/lib/biosdisk_ll.c

221 lines
5.9 KiB
C

/* $NetBSD: biosdisk_ll.c,v 1.11 2001/07/07 22:57:57 perry Exp $ */
/*
* Copyright (c) 1996
* Matthias Drochner. All rights reserved.
* Copyright (c) 1996
* Perry E. Metzger. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgements:
* This product includes software developed for the NetBSD Project
* by Matthias Drochner.
* This product includes software developed for the NetBSD Project
* by Perry E. Metzger.
* 4. The names of the authors may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* shared by bootsector startup (bootsectmain) and biosdisk.c
* needs lowlevel parts from bios_disk.S
*/
#include <lib/libsa/stand.h>
#include "biosdisk_ll.h"
#include "diskbuf.h"
extern long ourseg;
extern int get_diskinfo __P((int));
extern void int13_getextinfo __P((int, struct biosdisk_ext13info *));
extern int int13_extension __P((int));
extern int biosread __P((int, int, int, int, int, char *));
extern int biosextread __P((int, void *));
static int do_read __P((struct biosdisk_ll *, int, int, char *));
/*
* we get from get_diskinfo():
* xxxx %ch %cl %dh (registers after int13/8), ie
* xxxx cccc Csss hhhh
*/
#define SPT(di) (((di)>>8)&0x3f)
#define HEADS(di) (((di)&0xff)+1)
#define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1)
#ifndef BIOSDISK_RETRIES
#define BIOSDISK_RETRIES 5
#endif
int
set_geometry(d, ed)
struct biosdisk_ll *d;
struct biosdisk_ext13info *ed;
{
int diskinfo;
diskinfo = get_diskinfo(d->dev);
d->sec = SPT(diskinfo);
d->head = HEADS(diskinfo);
d->cyl = CYL(diskinfo);
d->chs_sectors = d->sec * d->head * d->cyl;
d->flags = 0;
if ((d->dev & 0x80) && int13_extension(d->dev)) {
d->flags |= BIOSDISK_EXT13;
if (ed != NULL)
int13_getextinfo(d->dev, ed);
}
/*
* get_diskinfo assumes floppy if BIOS call fails. Check at least
* "valid" geometry.
*/
return (!d->sec || !d->head);
}
/*
* Global shared "diskbuf" is used as read ahead buffer. 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 (DISKBUFSIZE / BIOSDISK_SECSIZE)
static int ra_dev;
static int ra_end;
static int ra_first;
static int
do_read(d, dblk, num, buf)
struct biosdisk_ll *d;
int dblk, num;
char *buf;
{
int cyl, head, sec, nsec, spc;
struct {
int8_t size;
int8_t resvd;
int16_t cnt;
int16_t off;
int16_t seg;
int64_t sec;
} ext;
if ((d->dev & 0x80) && (dblk + num) >= d->chs_sectors) {
if (!(d->flags & BIOSDISK_EXT13))
return -1;
ext.size = sizeof(ext);
ext.resvd = 0;
ext.cnt = num;
ext.off = (int32_t)buf;
ext.seg = ourseg;
ext.sec = dblk;
if (biosextread(d->dev, &ext))
return -1;
return ext.cnt;
} else {
spc = d->head * d->sec;
cyl = dblk / spc;
head = (dblk % spc) / d->sec;
sec = dblk % d->sec;
nsec = d->sec - sec;
if (nsec > num)
nsec = num;
if (biosread(d->dev, cyl, head, sec, nsec, buf))
return -1;
return nsec;
}
}
int
readsects(d, dblk, num, buf, cold) /* reads ahead if (!cold) */
struct biosdisk_ll *d;
int dblk, num;
char *buf;
int cold; /* don't use data segment or bss, don't call
* library functions */
{
while (num) {
int nsec;
/* check for usable data in read-ahead buffer */
if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev
|| dblk < ra_first || dblk >= ra_end) {
/* no, read from disk */
char *trbuf;
int maxsecs;
int retries = BIOSDISK_RETRIES;
if (cold) {
/* transfer directly to buffer */
trbuf = buf;
maxsecs = num;
} else {
/* fill read-ahead buffer */
trbuf = diskbuf;
maxsecs = RA_SECTORS;
diskbuf_user = 0; /* not yet valid */
}
while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) {
#ifdef DISK_DEBUG
if (!cold)
printf("read error dblk %d-%d\n", dblk,
dblk + maxsecs - 1);
#endif
if (--retries >= 0)
continue;
return (-1); /* XXX cannot output here if
* (cold) */
}
if (!cold) {
ra_dev = d->dev;
ra_first = dblk;
ra_end = dblk + nsec;
diskbuf_user = &ra_dev;
}
} else /* can take blocks from end of read-ahead
* buffer */
nsec = ra_end - dblk;
if (!cold) {
/* copy data from read-ahead to user buffer */
if (nsec > num)
nsec = num;
memcpy(buf,
diskbuf + (dblk - ra_first) * BIOSDISK_SECSIZE,
nsec * BIOSDISK_SECSIZE);
}
buf += nsec * BIOSDISK_SECSIZE;
num -= nsec;
dblk += nsec;
}
return (0);
}