biosdisk_ll.c revision 1.21
1 /* $NetBSD: biosdisk_ll.c,v 1.21 2005/06/22 06:06:34 junyoung 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Copyright (c) 1996 41 * Matthias Drochner. All rights reserved. 42 * Copyright (c) 1996 43 * Perry E. Metzger. All rights reserved. 44 * 45 * Redistribution and use in source and binary forms, with or without 46 * modification, are permitted provided that the following conditions 47 * are met: 48 * 1. Redistributions of source code must retain the above copyright 49 * notice, this list of conditions and the following disclaimer. 50 * 2. Redistributions in binary form must reproduce the above copyright 51 * notice, this list of conditions and the following disclaimer in the 52 * documentation and/or other materials provided with the distribution. 53 * 3. All advertising materials mentioning features or use of this software 54 * must display the following acknowledgements: 55 * This product includes software developed for the NetBSD Project 56 * by Matthias Drochner. 57 * This product includes software developed for the NetBSD Project 58 * by Perry E. Metzger. 59 * 4. The names of the authors may not be used to endorse or promote products 60 * derived from this software without specific prior written permission. 61 * 62 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 63 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 64 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 65 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 66 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 67 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 68 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 69 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 70 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 71 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 72 */ 73 74 /* 75 * shared by bootsector startup (bootsectmain) and biosdisk.c 76 * needs lowlevel parts from bios_disk.S 77 */ 78 79 #include <lib/libsa/stand.h> 80 81 #include "biosdisk_ll.h" 82 #include "diskbuf.h" 83 #include "libi386.h" 84 85 static int do_read(struct biosdisk_ll *, daddr_t, int, char *); 86 87 /* 88 * we get from get_diskinfo(): 89 * unused %ch %cl %dh (registers after int13/8), ie 90 * xxxxxxxx cccccccc CCssssss hhhhhhhh 91 */ 92 #define SPT(di) (((di)>>8)&0x3f) 93 #define HEADS(di) (((di)&0xff)+1) 94 #define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1) 95 96 #ifndef BIOSDISK_RETRIES 97 #define BIOSDISK_RETRIES 5 98 #endif 99 100 int 101 set_geometry(struct biosdisk_ll *d, struct biosdisk_ext13info *ed) 102 { 103 int diskinfo; 104 105 diskinfo = get_diskinfo(d->dev); 106 d->sec = SPT(diskinfo); 107 d->head = HEADS(diskinfo); 108 d->cyl = CYL(diskinfo); 109 d->chs_sectors = d->sec * d->head * d->cyl; 110 111 if (d->dev >= 0x80 + get_harddrives()) { 112 d->secsize = 2048; 113 d->type = BIOSDISK_TYPE_CD; 114 } else { 115 d->secsize = 512; 116 if (d->dev & 0x80) 117 d->type = BIOSDISK_TYPE_HD; 118 else 119 d->type = BIOSDISK_TYPE_FD; 120 } 121 122 /* 123 * Some broken BIOSes such as one found on Soltek SL-75DRV2 report 124 * that they don't support int13 extension for CD-ROM drives while 125 * they actually do. As a workaround, if the boot device is a CD we 126 * assume that the extension is available. Note that only very old 127 * BIOSes don't support the extended mode, and they don't work with 128 * ATAPI CD-ROM drives, either. So there's no problem. 129 */ 130 d->flags = 0; 131 if (d->type == BIOSDISK_TYPE_CD || 132 (d->type == BIOSDISK_TYPE_HD && int13_extension(d->dev))) { 133 d->flags |= BIOSDISK_EXT13; 134 if (ed != NULL) { 135 ed->size = sizeof(*ed); 136 int13_getextinfo(d->dev, ed); 137 } 138 } 139 140 /* 141 * If the drive is 2.88MB floppy drive, check that we can actually 142 * read sector >= 18. If not, assume 1.44MB floppy disk. 143 */ 144 if (d->type == BIOSDISK_TYPE_FD && SPT(diskinfo) == 36) { 145 char buf[512]; 146 147 if (biosread(d->dev, 0, 0, 18, 1, buf)) { 148 d->sec = 18; 149 d->chs_sectors /= 2; 150 } 151 } 152 153 return 0; 154 } 155 156 /* 157 * Global shared "diskbuf" is used as read ahead buffer. For reading from 158 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 159 * this buffer doesn't cross a 64K DMA boundary. 160 */ 161 static int ra_dev; 162 static int ra_end; 163 static int ra_first; 164 165 /* 166 * Because some older BIOSes have bugs in their int13 extensions, we 167 * only try to use the extended read if the I/O request can't be addressed 168 * using CHS. 169 * 170 * Of course, some BIOSes have bugs in ths CHS read, such as failing to 171 * function properly if the MBR table has a different geometry than the 172 * BIOS would generate internally for the device in question, and so we 173 * provide a way to force the extended on hard disks via a compile-time 174 * option. 175 */ 176 #if defined(FORCE_INT13EXT) 177 #define NEED_INT13EXT(d, dblk, num) \ 178 (((d)->dev & 0x80) != 0) 179 #else 180 #define NEED_INT13EXT(d, dblk, num) \ 181 (((d)->type == BIOSDISK_TYPE_CD) || \ 182 ((d)->type == BIOSDISK_TYPE_HD && \ 183 ((dblk) + (num)) >= (d)->chs_sectors)) 184 #endif 185 186 static int 187 do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf) 188 { 189 190 if (NEED_INT13EXT(d, dblk, num)) { 191 struct { 192 int8_t size; 193 int8_t resvd; 194 int16_t cnt; 195 int16_t off; 196 int16_t seg; 197 int64_t sec; 198 } ext; 199 200 if (!(d->flags & BIOSDISK_EXT13)) 201 return -1; 202 ext.size = sizeof(ext); 203 ext.resvd = 0; 204 ext.cnt = num; 205 /* seg:off of physical address */ 206 ext.off = (int)buf & 0xf; 207 ext.seg = vtophys(buf) >> 4; 208 ext.sec = dblk; 209 210 if (biosextread(d->dev, &ext)) { 211 (void)biosdiskreset(d->dev); 212 return -1; 213 } 214 215 return ext.cnt; 216 } else { 217 int cyl, head, sec, nsec, spc, dblk32; 218 219 dblk32 = (int)dblk; 220 spc = d->head * d->sec; 221 cyl = dblk32 / spc; 222 head = (dblk32 % spc) / d->sec; 223 sec = dblk32 % d->sec; 224 nsec = d->sec - sec; 225 226 if (nsec > num) 227 nsec = num; 228 229 if (biosread(d->dev, cyl, head, sec, nsec, buf)) { 230 (void)biosdiskreset(d->dev); 231 return -1; 232 } 233 234 return nsec; 235 } 236 } 237 238 /* 239 * NB if 'cold' is set below not all of the program is loaded, so 240 * mustn't use data segment, bss, call library functions or do read-ahead. 241 */ 242 int 243 readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold) 244 { 245 #ifdef BOOTXX 246 #define cold 1 /* collapse out references to diskbufp */ 247 #endif 248 while (num) { 249 int nsec; 250 251 /* check for usable data in read-ahead buffer */ 252 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 253 || dblk < ra_first || dblk >= ra_end) { 254 255 /* no, read from disk */ 256 char *trbuf; 257 int maxsecs; 258 int retries = BIOSDISK_RETRIES; 259 260 if (cold) { 261 /* transfer directly to buffer */ 262 trbuf = buf; 263 maxsecs = num; 264 } else { 265 /* fill read-ahead buffer */ 266 trbuf = alloc_diskbuf(0); /* no data yet */ 267 maxsecs = DISKBUFSIZE / d->secsize; 268 } 269 270 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { 271 #ifdef DISK_DEBUG 272 if (!cold) 273 printf("read error dblk %d-%d\n", dblk, 274 dblk + maxsecs - 1); 275 #endif 276 if (--retries >= 0) 277 continue; 278 return -1; /* XXX cannot output here if 279 * (cold) */ 280 } 281 if (!cold) { 282 ra_dev = d->dev; 283 ra_first = dblk; 284 ra_end = dblk + nsec; 285 diskbuf_user = &ra_dev; 286 } 287 } else /* can take blocks from end of read-ahead 288 * buffer */ 289 nsec = ra_end - dblk; 290 291 if (!cold) { 292 /* copy data from read-ahead to user buffer */ 293 if (nsec > num) 294 nsec = num; 295 memcpy(buf, 296 diskbufp + (dblk - ra_first) * d->secsize, 297 nsec * d->secsize); 298 } 299 buf += nsec * d->secsize; 300 num -= nsec; 301 dblk += nsec; 302 } 303 304 return 0; 305 } 306 307 /* 308 * Return the number of hard disk drives. 309 */ 310 int 311 get_harddrives(void) 312 { 313 /* 314 * Some BIOSes are buggy so that they return incorrect number 315 * of hard drives with int13/ah=8. We read a byte at 0040:0075 316 * instead, which is known to be always correct. 317 */ 318 int n = 0; 319 320 pvbcopy((void *)0x475, &n, 1); 321 322 return n; 323 } 324
Indexes created Tue Sep 30 11:09:46 GMT 2025