biosdisk_ll.c revision 1.28
1 /* $NetBSD: biosdisk_ll.c,v 1.28 2010/12/25 01:19:33 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/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 daddr_t ra_end; 157 static daddr_t 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 %"PRId64"-%PRId64\n", 268 dblk, (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 } 318
Indexes created Fri Oct 03 02:09:57 GMT 2025