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

   1 /*      $NetBSD: biosdisk_ll.c,v 1.25 2006/11/18 19:58:56 erh Exp $      */
   2
   3 /*-
   4  * Copyright (c) 2005 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Bang Jun-Young.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Copyright (c) 1996
  34  *      Matthias Drochner.  All rights reserved.
  35  * Copyright (c) 1996
  36  *      Perry E. Metzger.  All rights reserved.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. All advertising materials mentioning features or use of this software
  47  *    must display the following acknowledgements:
  48  *      This product includes software developed for the NetBSD Project
  49  *      by Matthias Drochner.
  50  *      This product includes software developed for the NetBSD Project
  51  *      by Perry E. Metzger.
  52  * 4. The names of the authors may not be used to endorse or promote products
  53  *    derived from this software without specific prior written permission.
  54  *
  55  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  56  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  57  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  58  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  59  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  60  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  61  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  62  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  63  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  64  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  65  */
  66
  67 /*
  68  * shared by bootsector startup (bootsectmain) and biosdisk.c
  69  * needs lowlevel parts from bios_disk.S
  70  */
  71
  72 #include <lib/libsa/stand.h>
  73
  74 #include "biosdisk_ll.h"
  75 #include "diskbuf.h"
  76 #include "libi386.h"
  77
  78 static int do_read(struct biosdisk_ll *, daddr_t, int, char *);
  79
  80 /*
  81  * we get from get_diskinfo():
  82  *      %ah      %ch      %cl      %dh (registers after int13/8), ie
  83  * xxxxxxxx cccccccc CCssssss hhhhhhhh
  84  */
  85 #define STATUS(di)      ((di)>>24)
  86 #define SPT(di)         (((di)>>8)&0x3f)
  87 #define HEADS(di)       (((di)&0xff)+1)
  88 #define CYL(di)         (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1)
  89
  90 #ifndef BIOSDISK_RETRIES
  91 #define BIOSDISK_RETRIES 5
  92 #endif
  93
  94 int
  95 set_geometry(struct biosdisk_ll *d, struct biosdisk_extinfo *ed)
  96 {
  97         int diskinfo;
  98
  99         diskinfo = biosdisk_getinfo(d->dev);
 100         d->sec = SPT(diskinfo);
 101         d->head = HEADS(diskinfo);
 102         d->cyl = CYL(diskinfo);
 103         d->chs_sectors = d->sec * d->head * d->cyl;
 104
 105         if (d->dev >= 0x80 + get_harddrives()) {
 106                 d->secsize = 2048;
 107                 d->type = BIOSDISK_TYPE_CD;
 108         } else {
 109                 d->secsize = 512;
 110                 if (d->dev & 0x80)
 111                         d->type = BIOSDISK_TYPE_HD;
 112                 else
 113                         d->type = BIOSDISK_TYPE_FD;
 114         }
 115
 116         /*
 117          * Some broken BIOSes such as one found on Soltek SL-75DRV2 report
 118          * that they don't support int13 extension for CD-ROM drives while
 119          * they actually do. As a workaround, if the boot device is a CD we
 120          * assume that the extension is available. Note that only very old
 121          * BIOSes don't support the extended mode, and they don't work with
 122          * ATAPI CD-ROM drives, either. So there's no problem.
 123          */
 124         d->flags = 0;
 125         if (d->type == BIOSDISK_TYPE_CD ||
 126             (d->type == BIOSDISK_TYPE_HD && biosdisk_int13ext(d->dev))) {
 127                 d->flags |= BIOSDISK_INT13EXT;
 128                 if (ed != NULL) {
 129                         ed->size = sizeof(*ed);
 130                         biosdisk_getextinfo(d->dev, ed);
 131                 }
 132         }
 133
 134         /*
 135          * If the drive is 2.88MB floppy drive, check that we can actually
 136          * read sector >= 18. If not, assume 1.44MB floppy disk.
 137          */
 138         if (d->type == BIOSDISK_TYPE_FD && SPT(diskinfo) == 36) {
 139                 char buf[512];
 140
 141                 if (biosdisk_read(d->dev, 0, 0, 18, 1, buf)) {
 142                         d->sec = 18;
 143                         d->chs_sectors /= 2;
 144                 }
 145         }
 146
 147         return 0;
 148 }
 149
 150 /*
 151  * Global shared "diskbuf" is used as read ahead buffer.  For reading from
 152  * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that
 153  * this buffer doesn't cross a 64K DMA boundary.
 154  */
 155 static int      ra_dev;
 156 static int      ra_end;
 157 static int      ra_first;
 158
 159 /*
 160  * Because some older BIOSes have bugs in their int13 extensions, we
 161  * only try to use the extended read if the I/O request can't be addressed
 162  * using CHS.
 163  *
 164  * Of course, some BIOSes have bugs in ths CHS read, such as failing to
 165  * function properly if the MBR table has a different geometry than the
 166  * BIOS would generate internally for the device in question, and so we
 167  * provide a way to force the extended on hard disks via a compile-time
 168  * option.
 169  */
 170 #if defined(FORCE_INT13EXT)
 171 #define NEED_INT13EXT(d, dblk, num)                             \
 172         (((d)->dev & 0x80) != 0)
 173 #else
 174 #define NEED_INT13EXT(d, dblk, num)                             \
 175         (((d)->type == BIOSDISK_TYPE_CD) ||                     \
 176          ((d)->type == BIOSDISK_TYPE_HD &&                      \
 177           ((dblk) + (num)) >= (d)->chs_sectors))
 178 #endif
 179
 180 static int
 181 do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf)
 182 {
 183
 184         if (NEED_INT13EXT(d, dblk, num)) {
 185                 struct {
 186                         int8_t size;
 187                         int8_t resvd;
 188                         int16_t cnt;
 189                         int16_t off;
 190                         int16_t seg;
 191                         int64_t sec;
 192                 } ext;
 193
 194                 if (!(d->flags & BIOSDISK_INT13EXT))
 195                         return -1;
 196                 ext.size = sizeof(ext);
 197                 ext.resvd = 0;
 198                 ext.cnt = num;
 199                 /* seg:off of physical address */
 200                 ext.off = (int)buf & 0xf;
 201                 ext.seg = vtophys(buf) >> 4;
 202                 ext.sec = dblk;
 203
 204                 if (biosdisk_extread(d->dev, &ext)) {
 205                         (void)biosdisk_reset(d->dev);
 206                         return -1;
 207                 }
 208
 209                 return ext.cnt;
 210         } else {
 211                 int cyl, head, sec, nsec, spc, dblk32;
 212
 213                 dblk32 = (int)dblk;
 214                 spc = d->head * d->sec;
 215                 cyl = dblk32 / spc;
 216                 head = (dblk32 % spc) / d->sec;
 217                 sec = dblk32 % d->sec;
 218                 nsec = d->sec - sec;
 219
 220                 if (nsec > num)
 221                         nsec = num;
 222
 223                 if (biosdisk_read(d->dev, cyl, head, sec, nsec, buf)) {
 224                         (void)biosdisk_reset(d->dev);
 225                         return -1;
 226                 }
 227
 228                 return nsec;
 229         }
 230 }
 231
 232 /*
 233  * NB if 'cold' is set below not all of the program is loaded, so
 234  * mustn't use data segment, bss, call library functions or do read-ahead.
 235  */
 236 int
 237 readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold)
 238 {
 239 #ifdef BOOTXX
 240 #define cold 1          /* collapse out references to diskbufp */
 241 #endif
 242         while (num) {
 243                 int nsec;
 244
 245                 /* check for usable data in read-ahead buffer */
 246                 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev
 247                     || dblk < ra_first || dblk >= ra_end) {
 248
 249                         /* no, read from disk */
 250                         char *trbuf;
 251                         int maxsecs;
 252                         int retries = BIOSDISK_RETRIES;
 253
 254                         if (cold) {
 255                                 /* transfer directly to buffer */
 256                                 trbuf = buf;
 257                                 maxsecs = num;
 258                         } else {
 259                                 /* fill read-ahead buffer */
 260                                 trbuf = alloc_diskbuf(0); /* no data yet */
 261                                 maxsecs = DISKBUFSIZE / d->secsize;
 262                         }
 263
 264                         while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) {
 265 #ifdef DISK_DEBUG
 266                                 if (!cold)
 267                                         printf("read error dblk %d-%d\n", (int)dblk,
 268                                                (int)(dblk + maxsecs - 1));
 269 #endif
 270                                 if (--retries >= 0)
 271                                         continue;
 272                                 return -1;      /* XXX cannot output here if
 273                                                  * (cold) */
 274                         }
 275                         if (!cold) {
 276                                 ra_dev = d->dev;
 277                                 ra_first = dblk;
 278                                 ra_end = dblk + nsec;
 279                                 diskbuf_user = &ra_dev;
 280                         }
 281                 } else          /* can take blocks from end of read-ahead
 282                                  * buffer */
 283                         nsec = ra_end - dblk;
 284
 285                 if (!cold) {
 286                         /* copy data from read-ahead to user buffer */
 287                         if (nsec > num)
 288                                 nsec = num;
 289                         memcpy(buf,
 290                                diskbufp + (dblk - ra_first) * d->secsize,
 291                                nsec * d->secsize);
 292                 }
 293                 buf += nsec * d->secsize;
 294                 num -= nsec;
 295                 dblk += nsec;
 296         }
 297
 298         return 0;
 299 }
 300
 301 /*
 302  * Return the number of hard disk drives.
 303  */
 304 int
 305 get_harddrives(void)
 306 {
 307         /*
 308          * Some BIOSes are buggy so that they return incorrect number
 309          * of hard drives with int13/ah=8. We read a byte at 0040:0075
 310          * instead, which is known to be always correct.
 311          */
 312         int n = 0;
 313
 314         pvbcopy((void *)0x475, &n, 1);
 315
 316         return n;
 317 }