320 lines
9.2 KiB
C
320 lines
9.2 KiB
C
/* $NetBSD: biosdisk_ll.c,v 1.31 2011/02/21 02:58:02 jakllsch Exp $ */
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/*-
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* Copyright (c) 2005 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Bang Jun-Young.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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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/libkern/libkern.h>
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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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#include "libi386.h"
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static int do_read(struct biosdisk_ll *, daddr_t, int, char *);
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/*
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* we get from get_diskinfo():
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* %ah %ch %cl %dh (registers after int13/8), ie
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* xxxxxxxx cccccccc CCssssss hhhhhhhh
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*/
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#define STATUS(di) ((di)>>24)
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#define SPT(di) (((di)>>8)&0x3f)
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#define HEADS(di) (((di)&0xff)+1)
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#define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1)
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#ifndef BIOSDISK_RETRIES
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#define BIOSDISK_RETRIES 5
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#endif
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int
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set_geometry(struct biosdisk_ll *d, struct biosdisk_extinfo *ed)
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{
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int diskinfo;
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diskinfo = biosdisk_getinfo(d->dev);
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d->sec = SPT(diskinfo);
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d->head = HEADS(diskinfo);
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d->cyl = CYL(diskinfo);
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d->chs_sectors = d->sec * d->head * d->cyl;
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if (d->dev >= 0x80 + get_harddrives()) {
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d->secsize = 2048;
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d->type = BIOSDISK_TYPE_CD;
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} else {
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d->secsize = 512;
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if (d->dev & 0x80)
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d->type = BIOSDISK_TYPE_HD;
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else
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d->type = BIOSDISK_TYPE_FD;
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}
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/*
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* Some broken BIOSes such as one found on Soltek SL-75DRV2 report
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* that they don't support int13 extension for CD-ROM drives while
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* they actually do. As a workaround, if the boot device is a CD we
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* assume that the extension is available. Note that only very old
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* BIOSes don't support the extended mode, and they don't work with
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* ATAPI CD-ROM drives, either. So there's no problem.
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*/
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d->flags = 0;
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if (d->type == BIOSDISK_TYPE_CD ||
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(d->type == BIOSDISK_TYPE_HD && biosdisk_int13ext(d->dev))) {
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d->flags |= BIOSDISK_INT13EXT;
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if (ed != NULL) {
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ed->size = sizeof(*ed);
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if (biosdisk_getextinfo(d->dev, ed) != 0)
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return -1;
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}
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}
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/*
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* If the drive is 2.88MB floppy drive, check that we can actually
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* read sector >= 18. If not, assume 1.44MB floppy disk.
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*/
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if (d->type == BIOSDISK_TYPE_FD && SPT(diskinfo) == 36) {
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char buf[512];
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if (biosdisk_read(d->dev, 0, 0, 18, 1, buf)) {
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d->sec = 18;
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d->chs_sectors /= 2;
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}
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}
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return 0;
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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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static int ra_dev;
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static daddr_t ra_end;
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static daddr_t ra_first;
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/*
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* Because some older BIOSes have bugs in their int13 extensions, we
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* only try to use the extended read if the I/O request can't be addressed
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* using CHS.
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*
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* Of course, some BIOSes have bugs in ths CHS read, such as failing to
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* function properly if the MBR table has a different geometry than the
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* BIOS would generate internally for the device in question, and so we
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* provide a way to force the extended on hard disks via a compile-time
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* option.
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*/
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#if defined(FORCE_INT13EXT)
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#define NEED_INT13EXT(d, dblk, num) \
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(((d)->dev & 0x80) != 0)
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#else
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#define NEED_INT13EXT(d, dblk, num) \
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(((d)->type == BIOSDISK_TYPE_CD) || \
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((d)->type == BIOSDISK_TYPE_HD && \
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((dblk) + (num)) >= (d)->chs_sectors))
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#endif
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static int
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do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf)
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{
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if (NEED_INT13EXT(d, dblk, num)) {
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struct {
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int8_t size;
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int8_t resvd;
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int16_t cnt;
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int16_t off;
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int16_t seg;
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int64_t sec;
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} ext;
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if (!(d->flags & BIOSDISK_INT13EXT))
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return -1;
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ext.size = sizeof(ext);
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ext.resvd = 0;
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ext.cnt = num;
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/* seg:off of physical address */
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ext.off = (int)buf & 0xf;
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ext.seg = vtophys(buf) >> 4;
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ext.sec = dblk;
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if (biosdisk_extread(d->dev, &ext)) {
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(void)biosdisk_reset(d->dev);
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return -1;
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}
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return ext.cnt;
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} else {
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int cyl, head, sec, nsec, spc, dblk32;
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dblk32 = (int)dblk;
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spc = d->head * d->sec;
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cyl = dblk32 / spc;
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head = (dblk32 % spc) / d->sec;
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sec = dblk32 % d->sec;
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nsec = d->sec - sec;
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if (nsec > num)
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nsec = num;
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if (biosdisk_read(d->dev, cyl, head, sec, nsec, buf)) {
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(void)biosdisk_reset(d->dev);
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return -1;
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}
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return nsec;
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}
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}
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/*
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* NB if 'cold' is set below not all of the program is loaded, so
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* mustn't use data segment, bss, call library functions or do read-ahead.
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*/
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int
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readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold)
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{
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#ifdef BOOTXX
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#define cold 1 /* collapse out references to diskbufp */
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#endif
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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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char *trbuf;
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int maxsecs;
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int retries = BIOSDISK_RETRIES;
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if (cold) {
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/* transfer directly to buffer */
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trbuf = buf;
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maxsecs = num;
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} else {
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/* fill read-ahead buffer */
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trbuf = alloc_diskbuf(0); /* no data yet */
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maxsecs = DISKBUFSIZE / d->secsize;
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}
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while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) {
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#ifdef DISK_DEBUG
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if (!cold)
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printf("read error dblk %"PRId64"-%"PRId64"\n",
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dblk, (dblk + maxsecs - 1));
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#endif
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if (--retries >= 0)
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continue;
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return -1; /* XXX cannot output here if
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* (cold) */
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}
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if (!cold) {
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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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} 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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memcpy(buf,
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diskbufp + (dblk - ra_first) * d->secsize,
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nsec * d->secsize);
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}
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buf += nsec * d->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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/*
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* Return the number of hard disk drives.
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*/
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int
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get_harddrives(void)
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{
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/*
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* Some BIOSes are buggy so that they return incorrect number
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* of hard drives with int13/ah=8. We read a byte at 0040:0075
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* instead, which is known to be always correct.
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*/
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int n = 0;
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pvbcopy((void *)0x475, &n, 1);
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return n;
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}
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