/* $NetBSD: biosdisk_ll.c,v 1.31 2011/02/21 02:58:02 jakllsch Exp $ */ /*- * Copyright (c) 2005 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Bang Jun-Young. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``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 FOUNDATION OR CONTRIBUTORS * 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. */ /* * 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/libkern/libkern.h> #include <lib/libsa/stand.h> #include "biosdisk_ll.h" #include "diskbuf.h" #include "libi386.h" static int do_read(struct biosdisk_ll *, daddr_t, int, char *); /* * we get from get_diskinfo(): * %ah %ch %cl %dh (registers after int13/8), ie * xxxxxxxx cccccccc CCssssss hhhhhhhh */ #define STATUS(di) ((di)>>24) #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(struct biosdisk_ll *d, struct biosdisk_extinfo *ed) { int diskinfo; diskinfo = biosdisk_getinfo(d->dev); d->sec = SPT(diskinfo); d->head = HEADS(diskinfo); d->cyl = CYL(diskinfo); d->chs_sectors = d->sec * d->head * d->cyl; if (d->dev >= 0x80 + get_harddrives()) { d->secsize = 2048; d->type = BIOSDISK_TYPE_CD; } else { d->secsize = 512; if (d->dev & 0x80) d->type = BIOSDISK_TYPE_HD; else d->type = BIOSDISK_TYPE_FD; } /* * Some broken BIOSes such as one found on Soltek SL-75DRV2 report * that they don't support int13 extension for CD-ROM drives while * they actually do. As a workaround, if the boot device is a CD we * assume that the extension is available. Note that only very old * BIOSes don't support the extended mode, and they don't work with * ATAPI CD-ROM drives, either. So there's no problem. */ d->flags = 0; if (d->type == BIOSDISK_TYPE_CD || (d->type == BIOSDISK_TYPE_HD && biosdisk_int13ext(d->dev))) { d->flags |= BIOSDISK_INT13EXT; if (ed != NULL) { ed->size = sizeof(*ed); if (biosdisk_getextinfo(d->dev, ed) != 0) return -1; } } /* * If the drive is 2.88MB floppy drive, check that we can actually * read sector >= 18. If not, assume 1.44MB floppy disk. */ if (d->type == BIOSDISK_TYPE_FD && SPT(diskinfo) == 36) { char buf[512]; if (biosdisk_read(d->dev, 0, 0, 18, 1, buf)) { d->sec = 18; d->chs_sectors /= 2; } } return 0; } /* * 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. */ static int ra_dev; static daddr_t ra_end; static daddr_t ra_first; /* * Because some older BIOSes have bugs in their int13 extensions, we * only try to use the extended read if the I/O request can't be addressed * using CHS. * * Of course, some BIOSes have bugs in ths CHS read, such as failing to * function properly if the MBR table has a different geometry than the * BIOS would generate internally for the device in question, and so we * provide a way to force the extended on hard disks via a compile-time * option. */ #if defined(FORCE_INT13EXT) #define NEED_INT13EXT(d, dblk, num) \ (((d)->dev & 0x80) != 0) #else #define NEED_INT13EXT(d, dblk, num) \ (((d)->type == BIOSDISK_TYPE_CD) || \ ((d)->type == BIOSDISK_TYPE_HD && \ ((dblk) + (num)) >= (d)->chs_sectors)) #endif static int do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf) { if (NEED_INT13EXT(d, dblk, num)) { struct { int8_t size; int8_t resvd; int16_t cnt; int16_t off; int16_t seg; int64_t sec; } ext; if (!(d->flags & BIOSDISK_INT13EXT)) return -1; ext.size = sizeof(ext); ext.resvd = 0; ext.cnt = num; /* seg:off of physical address */ ext.off = (int)buf & 0xf; ext.seg = vtophys(buf) >> 4; ext.sec = dblk; if (biosdisk_extread(d->dev, &ext)) { (void)biosdisk_reset(d->dev); return -1; } return ext.cnt; } else { int cyl, head, sec, nsec, spc, dblk32; dblk32 = (int)dblk; spc = d->head * d->sec; cyl = dblk32 / spc; head = (dblk32 % spc) / d->sec; sec = dblk32 % d->sec; nsec = d->sec - sec; if (nsec > num) nsec = num; if (biosdisk_read(d->dev, cyl, head, sec, nsec, buf)) { (void)biosdisk_reset(d->dev); return -1; } return nsec; } } /* * NB if 'cold' is set below not all of the program is loaded, so * mustn't use data segment, bss, call library functions or do read-ahead. */ int readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold) { #ifdef BOOTXX #define cold 1 /* collapse out references to diskbufp */ #endif 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 = alloc_diskbuf(0); /* no data yet */ maxsecs = DISKBUFSIZE / d->secsize; } while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { #ifdef DISK_DEBUG if (!cold) printf("read error dblk %"PRId64"-%"PRId64"\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, diskbufp + (dblk - ra_first) * d->secsize, nsec * d->secsize); } buf += nsec * d->secsize; num -= nsec; dblk += nsec; } return 0; } /* * Return the number of hard disk drives. */ int get_harddrives(void) { /* * Some BIOSes are buggy so that they return incorrect number * of hard drives with int13/ah=8. We read a byte at 0040:0075 * instead, which is known to be always correct. */ int n = 0; pvbcopy((void *)0x475, &n, 1); return n; }
