1 /* $NetBSD: biosdisk_ll.c,v 1.19 2004/08/23 09:45:53 junyoung Exp $ */ 2 3 /* 4 * Copyright (c) 1996 5 * Matthias Drochner. All rights reserved. 6 * Copyright (c) 1996 7 * Perry E. Metzger. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgements: 19 * This product includes software developed for the NetBSD Project 20 * by Matthias Drochner. 21 * This product includes software developed for the NetBSD Project 22 * by Perry E. Metzger. 23 * 4. The names of the authors may not be used to endorse or promote products 24 * derived from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 /* 39 * shared by bootsector startup (bootsectmain) and biosdisk.c 40 * needs lowlevel parts from bios_disk.S 41 */ 42 43 #include <lib/libsa/stand.h> 44 45 #include "biosdisk_ll.h" 46 #include "diskbuf.h" 47 #include "libi386.h" 48 49 static int do_read(struct biosdisk_ll *, daddr_t, int, char *); 50 51 /* 52 * we get from get_diskinfo(): 53 * xxxx %ch %cl %dh (registers after int13/8), ie 54 * xxxx cccc Csss hhhh 55 */ 56 #define SPT(di) (((di)>>8)&0x3f) 57 #define HEADS(di) (((di)&0xff)+1) 58 #define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1) 59 60 #ifndef BIOSDISK_RETRIES 61 #define BIOSDISK_RETRIES 5 62 #endif 63 64 int 65 set_geometry(struct biosdisk_ll *d, struct biosdisk_ext13info *ed) 66 { 67 int diskinfo; 68 char buf[512]; 69 70 diskinfo = get_diskinfo(d->dev); 71 d->sec = SPT(diskinfo); 72 d->head = HEADS(diskinfo); 73 d->cyl = CYL(diskinfo); 74 d->chs_sectors = d->sec * d->head * d->cyl; 75 76 d->flags = 0; 77 if ((d->dev & 0x80) && int13_extension(d->dev)) { 78 d->flags |= BIOSDISK_EXT13; 79 if (ed != NULL) { 80 ed->size = sizeof *ed; 81 int13_getextinfo(d->dev, ed); 82 } 83 } 84 85 /* 86 * If the drive is 2.88 floppy drive, check that we can actually 87 * read sector >= 18. If not, assume 1.44 floppy disk. 88 */ 89 if (d->dev == 0 && SPT(diskinfo) == 36) { 90 if (biosread(d->dev, 0, 0, 18, 1, buf)) { 91 d->sec = 18; 92 d->chs_sectors /= 2; 93 } 94 } 95 96 /* 97 * get_diskinfo assumes floppy if BIOS call fails. Check at least 98 * "valid" geometry. 99 */ 100 return (!d->sec || !d->head); 101 } 102 103 /* 104 * Global shared "diskbuf" is used as read ahead buffer. For reading from 105 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 106 * this buffer doesn't cross a 64K DMA boundary. 107 */ 108 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 109 static int ra_dev; 110 static int ra_end; 111 static int ra_first; 112 113 /* 114 * Because some older BIOSes have bugs in their int13 extensions, we 115 * only try to use the extended read if the I/O request can't be addressed 116 * using CHS. 117 * 118 * Of course, some BIOSes have bugs in ths CHS read, such as failing to 119 * function properly if the MBR table has a different geometry than the 120 * BIOS would generate internally for the device in question, and so we 121 * provide a way to force the extended on hard disks via a compile-time 122 * option. 123 */ 124 #if defined(FORCE_INT13EXT) 125 #define NEED_INT13EXT(d, dblk, num) \ 126 (((d)->dev & 0x80) != 0) 127 #else 128 #define NEED_INT13EXT(d, dblk, num) \ 129 (((d)->dev & 0x80) != 0 && ((dblk) + (num)) >= (d)->chs_sectors) 130 #endif 131 132 static int 133 do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf) 134 { 135 int cyl, head, sec, nsec, spc, dblk32; 136 struct { 137 int8_t size; 138 int8_t resvd; 139 int16_t cnt; 140 int16_t off; 141 int16_t seg; 142 int64_t sec; 143 } ext; 144 145 if (NEED_INT13EXT(d, dblk, num)) { 146 if (!(d->flags & BIOSDISK_EXT13)) 147 return -1; 148 ext.size = sizeof(ext); 149 ext.resvd = 0; 150 ext.cnt = num; 151 /* seg:off of physical address */ 152 ext.off = (int)buf & 0xf; 153 ext.seg = vtophys(buf) >> 4; 154 ext.sec = dblk; 155 156 if (biosextread(d->dev, &ext)) { 157 (void)biosdiskreset(d->dev); 158 return -1; 159 } 160 161 return ext.cnt; 162 } else { 163 dblk32 = (int)dblk; 164 spc = d->head * d->sec; 165 cyl = dblk32 / spc; 166 head = (dblk32 % spc) / d->sec; 167 sec = dblk32 % d->sec; 168 nsec = d->sec - sec; 169 170 if (nsec > num) 171 nsec = num; 172 173 if (biosread(d->dev, cyl, head, sec, nsec, buf)) { 174 (void)biosdiskreset(d->dev); 175 return -1; 176 } 177 178 return nsec; 179 } 180 } 181 182 /* NB if 'cold' is set below not all of the program is loaded, so 183 * musn't use data segment, bss, call library functions or do 184 * read-ahead. 185 */ 186 187 int 188 readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold) 189 { 190 #ifdef BOOTXX 191 #define cold 1 /* collapse out references to diskbufp */ 192 #endif 193 while (num) { 194 int nsec; 195 196 /* check for usable data in read-ahead buffer */ 197 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 198 || dblk < ra_first || dblk >= ra_end) { 199 200 /* no, read from disk */ 201 char *trbuf; 202 int maxsecs; 203 int retries = BIOSDISK_RETRIES; 204 205 if (cold) { 206 /* transfer directly to buffer */ 207 trbuf = buf; 208 maxsecs = num; 209 } else { 210 /* fill read-ahead buffer */ 211 trbuf = alloc_diskbuf(0); /* no data yet */ 212 maxsecs = RA_SECTORS; 213 } 214 215 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { 216 #ifdef DISK_DEBUG 217 if (!cold) 218 printf("read error dblk %d-%d\n", dblk, 219 dblk + maxsecs - 1); 220 #endif 221 if (--retries >= 0) 222 continue; 223 return (-1); /* XXX cannot output here if 224 * (cold) */ 225 } 226 if (!cold) { 227 ra_dev = d->dev; 228 ra_first = dblk; 229 ra_end = dblk + nsec; 230 diskbuf_user = &ra_dev; 231 } 232 } else /* can take blocks from end of read-ahead 233 * buffer */ 234 nsec = ra_end - dblk; 235 236 if (!cold) { 237 /* copy data from read-ahead to user buffer */ 238 if (nsec > num) 239 nsec = num; 240 memcpy(buf, 241 diskbufp + (dblk - ra_first) * BIOSDISK_SECSIZE, 242 nsec * BIOSDISK_SECSIZE); 243 } 244 buf += nsec * BIOSDISK_SECSIZE; 245 num -= nsec; 246 dblk += nsec; 247 } 248 249 return (0); 250 } 251