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

   1 /*      $NetBSD: biosdisk_ll.c,v 1.31 2011/02/21 02:58:02 jakllsch 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/libkern/libkern.h>
  73 #include <lib/libsa/stand.h>
  74
  75 #include "biosdisk_ll.h"
  76 #include "diskbuf.h"
  77 #include "libi386.h"
  78
  79 static int do_read(struct biosdisk_ll *, daddr_t, int, char *);
  80
  81 /*
  82  * we get from get_diskinfo():
  83  *      %ah      %ch      %cl      %dh (registers after int13/8), ie
  84  * xxxxxxxx cccccccc CCssssss hhhhhhhh
  85  */
  86 #define STATUS(di)      ((di)>>24)
  87 #define SPT(di)         (((di)>>8)&0x3f)
  88 #define HEADS(di)       (((di)&0xff)+1)
  89 #define CYL(di)         (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1)
  90
  91 #ifndef BIOSDISK_RETRIES
  92 #define BIOSDISK_RETRIES 5
  93 #endif
  94
  95 int
  96 set_geometry(struct biosdisk_ll *d, struct biosdisk_extinfo *ed)
  97 {
  98         int diskinfo;
  99
 100         diskinfo = biosdisk_getinfo(d->dev);
 101         d->sec = SPT(diskinfo);
 102         d->head = HEADS(diskinfo);
 103         d->cyl = CYL(diskinfo);
 104         d->chs_sectors = d->sec * d->head * d->cyl;
 105
 106         if (d->dev >= 0x80 + get_harddrives()) {
 107                 d->secsize = 2048;
 108                 d->type = BIOSDISK_TYPE_CD;
 109         } else {
 110                 d->secsize = 512;
 111                 if (d->dev & 0x80)
 112                         d->type = BIOSDISK_TYPE_HD;
 113                 else
 114                         d->type = BIOSDISK_TYPE_FD;
 115         }
 116
 117         /*
 118          * Some broken BIOSes such as one found on Soltek SL-75DRV2 report
 119          * that they don't support int13 extension for CD-ROM drives while
 120          * they actually do. As a workaround, if the boot device is a CD we
 121          * assume that the extension is available. Note that only very old
 122          * BIOSes don't support the extended mode, and they don't work with
 123          * ATAPI CD-ROM drives, either. So there's no problem.
 124          */
 125         d->flags = 0;
 126         if (d->type == BIOSDISK_TYPE_CD ||
 127             (d->type == BIOSDISK_TYPE_HD && biosdisk_int13ext(d->dev))) {
 128                 d->flags |= BIOSDISK_INT13EXT;
 129                 if (ed != NULL) {
 130                         ed->size = sizeof(*ed);
 131                         if (biosdisk_getextinfo(d->dev, ed) != 0)
 132                                 return -1;
 133                 }
 134         }
 135
 136         /*
 137          * If the drive is 2.88MB floppy drive, check that we can actually
 138          * read sector >= 18. If not, assume 1.44MB floppy disk.
 139          */
 140         if (d->type == BIOSDISK_TYPE_FD && SPT(diskinfo) == 36) {
 141                 char buf[512];
 142
 143                 if (biosdisk_read(d->dev, 0, 0, 18, 1, buf)) {
 144                         d->sec = 18;
 145                         d->chs_sectors /= 2;
 146                 }
 147         }
 148
 149         return 0;
 150 }
 151
 152 /*
 153  * Global shared "diskbuf" is used as read ahead buffer.  For reading from
 154  * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that
 155  * this buffer doesn't cross a 64K DMA boundary.
 156  */
 157 static int      ra_dev;
 158 static daddr_t  ra_end;
 159 static daddr_t  ra_first;
 160
 161 /*
 162  * Because some older BIOSes have bugs in their int13 extensions, we
 163  * only try to use the extended read if the I/O request can't be addressed
 164  * using CHS.
 165  *
 166  * Of course, some BIOSes have bugs in ths CHS read, such as failing to
 167  * function properly if the MBR table has a different geometry than the
 168  * BIOS would generate internally for the device in question, and so we
 169  * provide a way to force the extended on hard disks via a compile-time
 170  * option.
 171  */
 172 #if defined(FORCE_INT13EXT)
 173 #define NEED_INT13EXT(d, dblk, num)                             \
 174         (((d)->dev & 0x80) != 0)
 175 #else
 176 #define NEED_INT13EXT(d, dblk, num)                             \
 177         (((d)->type == BIOSDISK_TYPE_CD) ||                     \
 178          ((d)->type == BIOSDISK_TYPE_HD &&                      \
 179           ((dblk) + (num)) >= (d)->chs_sectors))
 180 #endif
 181
 182 static int
 183 do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf)
 184 {
 185
 186         if (NEED_INT13EXT(d, dblk, num)) {
 187                 struct {
 188                         int8_t size;
 189                         int8_t resvd;
 190                         int16_t cnt;
 191                         int16_t off;
 192                         int16_t seg;
 193                         int64_t sec;
 194                 } ext;
 195
 196                 if (!(d->flags & BIOSDISK_INT13EXT))
 197                         return -1;
 198                 ext.size = sizeof(ext);
 199                 ext.resvd = 0;
 200                 ext.cnt = num;
 201                 /* seg:off of physical address */
 202                 ext.off = (int)buf & 0xf;
 203                 ext.seg = vtophys(buf) >> 4;
 204                 ext.sec = dblk;
 205
 206                 if (biosdisk_extread(d->dev, &ext)) {
 207                         (void)biosdisk_reset(d->dev);
 208                         return -1;
 209                 }
 210
 211                 return ext.cnt;
 212         } else {
 213                 int cyl, head, sec, nsec, spc, dblk32;
 214
 215                 dblk32 = (int)dblk;
 216                 spc = d->head * d->sec;
 217                 cyl = dblk32 / spc;
 218                 head = (dblk32 % spc) / d->sec;
 219                 sec = dblk32 % d->sec;
 220                 nsec = d->sec - sec;
 221
 222                 if (nsec > num)
 223                         nsec = num;
 224
 225                 if (biosdisk_read(d->dev, cyl, head, sec, nsec, buf)) {
 226                         (void)biosdisk_reset(d->dev);
 227                         return -1;
 228                 }
 229
 230                 return nsec;
 231         }
 232 }
 233
 234 /*
 235  * NB if 'cold' is set below not all of the program is loaded, so
 236  * mustn't use data segment, bss, call library functions or do read-ahead.
 237  */
 238 int
 239 readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold)
 240 {
 241 #ifdef BOOTXX
 242 #define cold 1          /* collapse out references to diskbufp */
 243 #endif
 244         while (num) {
 245                 int nsec;
 246
 247                 /* check for usable data in read-ahead buffer */
 248                 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev
 249                     || dblk < ra_first || dblk >= ra_end) {
 250
 251                         /* no, read from disk */
 252                         char *trbuf;
 253                         int maxsecs;
 254                         int retries = BIOSDISK_RETRIES;
 255
 256                         if (cold) {
 257                                 /* transfer directly to buffer */
 258                                 trbuf = buf;
 259                                 maxsecs = num;
 260                         } else {
 261                                 /* fill read-ahead buffer */
 262                                 trbuf = alloc_diskbuf(0); /* no data yet */
 263                                 maxsecs = DISKBUFSIZE / d->secsize;
 264                         }
 265
 266                         while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) {
 267 #ifdef DISK_DEBUG
 268                                 if (!cold)
 269                                         printf("read error dblk %"PRId64"-%"PRId64"\n",
 270                                             dblk, (dblk + maxsecs - 1));
 271 #endif
 272                                 if (--retries >= 0)
 273                                         continue;
 274                                 return -1;      /* XXX cannot output here if
 275                                                  * (cold) */
 276                         }
 277                         if (!cold) {
 278                                 ra_dev = d->dev;
 279                                 ra_first = dblk;
 280                                 ra_end = dblk + nsec;
 281                                 diskbuf_user = &ra_dev;
 282                         }
 283                 } else          /* can take blocks from end of read-ahead
 284                                  * buffer */
 285                         nsec = ra_end - dblk;
 286
 287                 if (!cold) {
 288                         /* copy data from read-ahead to user buffer */
 289                         if (nsec > num)
 290                                 nsec = num;
 291                         memcpy(buf,
 292                                diskbufp + (dblk - ra_first) * d->secsize,
 293                                nsec * d->secsize);
 294                 }
 295                 buf += nsec * d->secsize;
 296                 num -= nsec;
 297                 dblk += nsec;
 298         }
 299
 300         return 0;
 301 }
 302
 303 /*
 304  * Return the number of hard disk drives.
 305  */
 306 int
 307 get_harddrives(void)
 308 {
 309         /*
 310          * Some BIOSes are buggy so that they return incorrect number
 311          * of hard drives with int13/ah=8. We read a byte at 0040:0075
 312          * instead, which is known to be always correct.
 313          */
 314         int n = 0;
 315
 316         pvbcopy((void *)0x475, &n, 1);
 317
 318         return n;
 319 }