biosdisk_ll.c revision 1.15
1 /* $NetBSD: biosdisk_ll.c,v 1.15 2003/02/07 00:46:08 dsl 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 48 extern int get_diskinfo(int); 49 extern void int13_getextinfo(int, struct biosdisk_ext13info *); 50 extern int int13_extension(int); 51 extern int biosread(int, int, int, int, int, void *); 52 extern int biosdiskreset(int); 53 extern int biosextread(int, void *); 54 static int do_read(struct biosdisk_ll *, int, int, char *); 55 extern u_int vtophys(void *); 56 57 /* 58 * we get from get_diskinfo(): 59 * xxxx %ch %cl %dh (registers after int13/8), ie 60 * xxxx cccc Csss hhhh 61 */ 62 #define SPT(di) (((di)>>8)&0x3f) 63 #define HEADS(di) (((di)&0xff)+1) 64 #define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1) 65 66 #ifndef BIOSDISK_RETRIES 67 #define BIOSDISK_RETRIES 5 68 #endif 69 70 int 71 set_geometry(struct biosdisk_ll *d, struct biosdisk_ext13info *ed) 72 { 73 int diskinfo; 74 char buf[512]; 75 76 diskinfo = get_diskinfo(d->dev); 77 d->sec = SPT(diskinfo); 78 d->head = HEADS(diskinfo); 79 d->cyl = CYL(diskinfo); 80 d->chs_sectors = d->sec * d->head * d->cyl; 81 82 d->flags = 0; 83 if ((d->dev & 0x80) && int13_extension(d->dev)) { 84 d->flags |= BIOSDISK_EXT13; 85 if (ed != NULL) 86 int13_getextinfo(d->dev, ed); 87 } 88 89 /* 90 * If the drive is 2.88 floppy drive, check that we can actually 91 * read sector >= 18. If not, assume 1.44 floppy disk. 92 */ 93 if (d->dev == 0 && SPT(diskinfo) == 36) { 94 if (biosread(d->dev, 0, 0, 18, 1, buf)) { 95 d->sec = 18; 96 d->chs_sectors /= 2; 97 } 98 } 99 100 /* 101 * get_diskinfo assumes floppy if BIOS call fails. Check at least 102 * "valid" geometry. 103 */ 104 return (!d->sec || !d->head); 105 } 106 107 /* 108 * Global shared "diskbuf" is used as read ahead buffer. For reading from 109 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 110 * this buffer doesn't cross a 64K DMA boundary. 111 */ 112 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 113 static int ra_dev; 114 static int ra_end; 115 static int ra_first; 116 117 static int 118 do_read(struct biosdisk_ll *d, int dblk, int num, char *buf) 119 { 120 int cyl, head, sec, nsec, spc; 121 struct { 122 int8_t size; 123 int8_t resvd; 124 int16_t cnt; 125 int16_t off; 126 int16_t seg; 127 int64_t sec; 128 } ext; 129 130 if ((d->dev & 0x80) && (dblk + num) >= d->chs_sectors) { 131 if (!(d->flags & BIOSDISK_EXT13)) 132 return -1; 133 ext.size = sizeof(ext); 134 ext.resvd = 0; 135 ext.cnt = num; 136 /* seg:off of physical address */ 137 ext.off = (int)buf & 0xf; 138 ext.seg = vtophys(buf) >> 4; 139 ext.sec = dblk; 140 141 if (biosextread(d->dev, &ext)) { 142 (void)biosdiskreset(d->dev); 143 return -1; 144 } 145 146 return ext.cnt; 147 } else { 148 spc = d->head * d->sec; 149 cyl = dblk / spc; 150 head = (dblk % spc) / d->sec; 151 sec = dblk % d->sec; 152 nsec = d->sec - sec; 153 154 if (nsec > num) 155 nsec = num; 156 157 if (biosread(d->dev, cyl, head, sec, nsec, buf)) { 158 (void)biosdiskreset(d->dev); 159 return -1; 160 } 161 162 return nsec; 163 } 164 } 165 166 /* NB if 'cold' is set below not all of the program is loaded, so 167 * musn't use data segment, bss, call library functions or do 168 * read-ahead. 169 */ 170 171 int 172 readsects(struct biosdisk_ll *d, int dblk, int num, char *buf, int cold) 173 { 174 while (num) { 175 int nsec; 176 177 /* check for usable data in read-ahead buffer */ 178 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 179 || dblk < ra_first || dblk >= ra_end) { 180 181 /* no, read from disk */ 182 char *trbuf; 183 int maxsecs; 184 int retries = BIOSDISK_RETRIES; 185 186 if (cold) { 187 /* transfer directly to buffer */ 188 trbuf = buf; 189 maxsecs = num; 190 } else { 191 /* fill read-ahead buffer */ 192 trbuf = alloc_diskbuf(0); /* no data yet */ 193 maxsecs = RA_SECTORS; 194 } 195 196 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { 197 #ifdef DISK_DEBUG 198 if (!cold) 199 printf("read error dblk %d-%d\n", dblk, 200 dblk + maxsecs - 1); 201 #endif 202 if (--retries >= 0) 203 continue; 204 return (-1); /* XXX cannot output here if 205 * (cold) */ 206 } 207 if (!cold) { 208 ra_dev = d->dev; 209 ra_first = dblk; 210 ra_end = dblk + nsec; 211 diskbuf_user = &ra_dev; 212 } 213 } else /* can take blocks from end of read-ahead 214 * buffer */ 215 nsec = ra_end - dblk; 216 217 if (!cold) { 218 /* copy data from read-ahead to user buffer */ 219 if (nsec > num) 220 nsec = num; 221 memcpy(buf, 222 diskbufp + (dblk - ra_first) * BIOSDISK_SECSIZE, 223 nsec * BIOSDISK_SECSIZE); 224 } 225 buf += nsec * BIOSDISK_SECSIZE; 226 num -= nsec; 227 dblk += nsec; 228 } 229 230 return (0); 231 } 232
Indexes created Tue Sep 30 11:09:46 GMT 2025