1 /* $NetBSD: biosdisk_ll.c,v 1.12 2002/10/10 18:52:42 dyoung 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 long ourseg; 49 50 extern int get_diskinfo __P((int)); 51 extern void int13_getextinfo __P((int, struct biosdisk_ext13info *)); 52 extern int int13_extension __P((int)); 53 extern int biosdiskreset __P((int)); 54 extern int biosread __P((int, int, int, int, int, char *)); 55 extern int biosextread __P((int, void *)); 56 static int do_read __P((struct biosdisk_ll *, int, int, char *)); 57 58 /* 59 * we get from get_diskinfo(): 60 * xxxx %ch %cl %dh (registers after int13/8), ie 61 * xxxx cccc Csss hhhh 62 */ 63 #define SPT(di) (((di)>>8)&0x3f) 64 #define HEADS(di) (((di)&0xff)+1) 65 #define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1) 66 67 #ifndef BIOSDISK_RETRIES 68 #define BIOSDISK_RETRIES 5 69 #endif 70 71 int 72 set_geometry(d, ed) 73 struct biosdisk_ll *d; 74 struct biosdisk_ext13info *ed; 75 { 76 int diskinfo; 77 78 diskinfo = get_diskinfo(d->dev); 79 d->sec = SPT(diskinfo); 80 d->head = HEADS(diskinfo); 81 d->cyl = CYL(diskinfo); 82 d->chs_sectors = d->sec * d->head * d->cyl; 83 84 d->flags = 0; 85 if ((d->dev & 0x80) && int13_extension(d->dev)) { 86 d->flags |= BIOSDISK_EXT13; 87 if (ed != NULL) 88 int13_getextinfo(d->dev, ed); 89 } 90 91 /* 92 * get_diskinfo assumes floppy if BIOS call fails. Check at least 93 * "valid" geometry. 94 */ 95 return (!d->sec || !d->head); 96 } 97 98 /* 99 * Global shared "diskbuf" is used as read ahead buffer. For reading from 100 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 101 * this buffer doesn't cross a 64K DMA boundary. 102 */ 103 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 104 static int ra_dev; 105 static int ra_end; 106 static int ra_first; 107 108 static int 109 do_read(d, dblk, num, buf) 110 struct biosdisk_ll *d; 111 int dblk, num; 112 char *buf; 113 { 114 int cyl, head, sec, nsec, spc; 115 struct { 116 int8_t size; 117 int8_t resvd; 118 int16_t cnt; 119 int16_t off; 120 int16_t seg; 121 int64_t sec; 122 } ext; 123 124 if ((d->dev & 0x80) && (dblk + num) >= d->chs_sectors) { 125 if (!(d->flags & BIOSDISK_EXT13)) 126 return -1; 127 ext.size = sizeof(ext); 128 ext.resvd = 0; 129 ext.cnt = num; 130 ext.off = (int32_t)buf; 131 ext.seg = ourseg; 132 ext.sec = dblk; 133 134 if (biosextread(d->dev, &ext)) { 135 (void)biosdiskreset(d->dev); 136 return -1; 137 } 138 139 return ext.cnt; 140 } else { 141 spc = d->head * d->sec; 142 cyl = dblk / spc; 143 head = (dblk % spc) / d->sec; 144 sec = dblk % d->sec; 145 nsec = d->sec - sec; 146 147 if (nsec > num) 148 nsec = num; 149 150 if (biosread(d->dev, cyl, head, sec, nsec, buf)) { 151 (void)biosdiskreset(d->dev); 152 return -1; 153 } 154 155 return nsec; 156 } 157 } 158 159 int 160 readsects(d, dblk, num, buf, cold) /* reads ahead if (!cold) */ 161 struct biosdisk_ll *d; 162 int dblk, num; 163 char *buf; 164 int cold; /* don't use data segment or bss, don't call 165 * library functions */ 166 { 167 while (num) { 168 int nsec; 169 170 /* check for usable data in read-ahead buffer */ 171 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 172 || dblk < ra_first || dblk >= ra_end) { 173 174 /* no, read from disk */ 175 char *trbuf; 176 int maxsecs; 177 int retries = BIOSDISK_RETRIES; 178 179 if (cold) { 180 /* transfer directly to buffer */ 181 trbuf = buf; 182 maxsecs = num; 183 } else { 184 /* fill read-ahead buffer */ 185 trbuf = diskbuf; 186 maxsecs = RA_SECTORS; 187 diskbuf_user = 0; /* not yet valid */ 188 } 189 190 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { 191 #ifdef DISK_DEBUG 192 if (!cold) 193 printf("read error dblk %d-%d\n", dblk, 194 dblk + maxsecs - 1); 195 #endif 196 if (--retries >= 0) 197 continue; 198 return (-1); /* XXX cannot output here if 199 * (cold) */ 200 } 201 if (!cold) { 202 ra_dev = d->dev; 203 ra_first = dblk; 204 ra_end = dblk + nsec; 205 diskbuf_user = &ra_dev; 206 } 207 } else /* can take blocks from end of read-ahead 208 * buffer */ 209 nsec = ra_end - dblk; 210 211 if (!cold) { 212 /* copy data from read-ahead to user buffer */ 213 if (nsec > num) 214 nsec = num; 215 memcpy(buf, 216 diskbuf + (dblk - ra_first) * BIOSDISK_SECSIZE, 217 nsec * BIOSDISK_SECSIZE); 218 } 219 buf += nsec * BIOSDISK_SECSIZE; 220 num -= nsec; 221 dblk += nsec; 222 } 223 224 return (0); 225 } 226