biosdisk_ll.c revision 1.14
1 /* $NetBSD: biosdisk_ll.c,v 1.14 2003/02/01 14:48:17 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 75 diskinfo = get_diskinfo(d->dev); 76 d->sec = SPT(diskinfo); 77 d->head = HEADS(diskinfo); 78 d->cyl = CYL(diskinfo); 79 d->chs_sectors = d->sec * d->head * d->cyl; 80 81 d->flags = 0; 82 if ((d->dev & 0x80) && int13_extension(d->dev)) { 83 d->flags |= BIOSDISK_EXT13; 84 if (ed != NULL) 85 int13_getextinfo(d->dev, ed); 86 } 87 88 /* 89 * If the drive is 2.88 floppy drive, check that we can actually 90 * read sector >= 18. If not, assume 1.44 floppy disk. 91 */ 92 if (d->dev == 0 && SPT(diskinfo) == 36) { 93 if (biosread(d->dev, 0, 0, 18, 1, alloc_diskbuf(0))) { 94 d->sec = 18; 95 d->chs_sectors /= 2; 96 } 97 } 98 99 /* 100 * get_diskinfo assumes floppy if BIOS call fails. Check at least 101 * "valid" geometry. 102 */ 103 return (!d->sec || !d->head); 104 } 105 106 /* 107 * Global shared "diskbuf" is used as read ahead buffer. For reading from 108 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 109 * this buffer doesn't cross a 64K DMA boundary. 110 */ 111 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 112 static int ra_dev; 113 static int ra_end; 114 static int ra_first; 115 116 static int 117 do_read(struct biosdisk_ll *d, int dblk, int num, char *buf) 118 { 119 int cyl, head, sec, nsec, spc; 120 struct { 121 int8_t size; 122 int8_t resvd; 123 int16_t cnt; 124 int16_t off; 125 int16_t seg; 126 int64_t sec; 127 } ext; 128 129 if ((d->dev & 0x80) && (dblk + num) >= d->chs_sectors) { 130 if (!(d->flags & BIOSDISK_EXT13)) 131 return -1; 132 ext.size = sizeof(ext); 133 ext.resvd = 0; 134 ext.cnt = num; 135 /* seg:off of physical address */ 136 ext.off = (int)buf & 0xf; 137 ext.seg = vtophys(buf) >> 4; 138 ext.sec = dblk; 139 140 if (biosextread(d->dev, &ext)) { 141 (void)biosdiskreset(d->dev); 142 return -1; 143 } 144 145 return ext.cnt; 146 } else { 147 spc = d->head * d->sec; 148 cyl = dblk / spc; 149 head = (dblk % spc) / d->sec; 150 sec = dblk % d->sec; 151 nsec = d->sec - sec; 152 153 if (nsec > num) 154 nsec = num; 155 156 if (biosread(d->dev, cyl, head, sec, nsec, buf)) { 157 (void)biosdiskreset(d->dev); 158 return -1; 159 } 160 161 return nsec; 162 } 163 } 164 165 /* NB if 'cold' is set below not all of the program is loaded, so 166 * musn't use data segment, bss, call library functions or do 167 * read-ahead. 168 */ 169 170 int 171 readsects(struct biosdisk_ll *d, int dblk, int num, char *buf, int cold) 172 { 173 while (num) { 174 int nsec; 175 176 /* check for usable data in read-ahead buffer */ 177 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 178 || dblk < ra_first || dblk >= ra_end) { 179 180 /* no, read from disk */ 181 char *trbuf; 182 int maxsecs; 183 int retries = BIOSDISK_RETRIES; 184 185 if (cold) { 186 /* transfer directly to buffer */ 187 trbuf = buf; 188 maxsecs = num; 189 } else { 190 /* fill read-ahead buffer */ 191 trbuf = alloc_diskbuf(0); /* no data yet */ 192 maxsecs = RA_SECTORS; 193 } 194 195 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { 196 #ifdef DISK_DEBUG 197 if (!cold) 198 printf("read error dblk %d-%d\n", dblk, 199 dblk + maxsecs - 1); 200 #endif 201 if (--retries >= 0) 202 continue; 203 return (-1); /* XXX cannot output here if 204 * (cold) */ 205 } 206 if (!cold) { 207 ra_dev = d->dev; 208 ra_first = dblk; 209 ra_end = dblk + nsec; 210 diskbuf_user = &ra_dev; 211 } 212 } else /* can take blocks from end of read-ahead 213 * buffer */ 214 nsec = ra_end - dblk; 215 216 if (!cold) { 217 /* copy data from read-ahead to user buffer */ 218 if (nsec > num) 219 nsec = num; 220 memcpy(buf, 221 diskbufp + (dblk - ra_first) * BIOSDISK_SECSIZE, 222 nsec * BIOSDISK_SECSIZE); 223 } 224 buf += nsec * BIOSDISK_SECSIZE; 225 num -= nsec; 226 dblk += nsec; 227 } 228 229 return (0); 230 } 231
Indexes created Tue Sep 30 07:10:03 GMT 2025