1 /* $NetBSD: biosdisk_ll.c,v 1.11 2001/07/07 22:57:57 perry 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 biosread __P((int, int, int, int, int, char *)); 54 extern int biosextread __P((int, void *)); 55 static int do_read __P((struct biosdisk_ll *, int, int, char *)); 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(d, ed) 72 struct biosdisk_ll *d; 73 struct biosdisk_ext13info *ed; 74 { 75 int diskinfo; 76 77 diskinfo = get_diskinfo(d->dev); 78 d->sec = SPT(diskinfo); 79 d->head = HEADS(diskinfo); 80 d->cyl = CYL(diskinfo); 81 d->chs_sectors = d->sec * d->head * d->cyl; 82 83 d->flags = 0; 84 if ((d->dev & 0x80) && int13_extension(d->dev)) { 85 d->flags |= BIOSDISK_EXT13; 86 if (ed != NULL) 87 int13_getextinfo(d->dev, ed); 88 } 89 90 /* 91 * get_diskinfo assumes floppy if BIOS call fails. Check at least 92 * "valid" geometry. 93 */ 94 return (!d->sec || !d->head); 95 } 96 97 /* 98 * Global shared "diskbuf" is used as read ahead buffer. For reading from 99 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 100 * this buffer doesn't cross a 64K DMA boundary. 101 */ 102 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 103 static int ra_dev; 104 static int ra_end; 105 static int ra_first; 106 107 static int 108 do_read(d, dblk, num, buf) 109 struct biosdisk_ll *d; 110 int dblk, num; 111 char *buf; 112 { 113 int cyl, head, sec, nsec, spc; 114 struct { 115 int8_t size; 116 int8_t resvd; 117 int16_t cnt; 118 int16_t off; 119 int16_t seg; 120 int64_t sec; 121 } ext; 122 123 if ((d->dev & 0x80) && (dblk + num) >= d->chs_sectors) { 124 if (!(d->flags & BIOSDISK_EXT13)) 125 return -1; 126 ext.size = sizeof(ext); 127 ext.resvd = 0; 128 ext.cnt = num; 129 ext.off = (int32_t)buf; 130 ext.seg = ourseg; 131 ext.sec = dblk; 132 133 if (biosextread(d->dev, &ext)) 134 return -1; 135 136 return ext.cnt; 137 } else { 138 spc = d->head * d->sec; 139 cyl = dblk / spc; 140 head = (dblk % spc) / d->sec; 141 sec = dblk % d->sec; 142 nsec = d->sec - sec; 143 144 if (nsec > num) 145 nsec = num; 146 147 if (biosread(d->dev, cyl, head, sec, nsec, buf)) 148 return -1; 149 150 return nsec; 151 } 152 } 153 154 int 155 readsects(d, dblk, num, buf, cold) /* reads ahead if (!cold) */ 156 struct biosdisk_ll *d; 157 int dblk, num; 158 char *buf; 159 int cold; /* don't use data segment or bss, don't call 160 * library functions */ 161 { 162 while (num) { 163 int nsec; 164 165 /* check for usable data in read-ahead buffer */ 166 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 167 || dblk < ra_first || dblk >= ra_end) { 168 169 /* no, read from disk */ 170 char *trbuf; 171 int maxsecs; 172 int retries = BIOSDISK_RETRIES; 173 174 if (cold) { 175 /* transfer directly to buffer */ 176 trbuf = buf; 177 maxsecs = num; 178 } else { 179 /* fill read-ahead buffer */ 180 trbuf = diskbuf; 181 maxsecs = RA_SECTORS; 182 diskbuf_user = 0; /* not yet valid */ 183 } 184 185 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) { 186 #ifdef DISK_DEBUG 187 if (!cold) 188 printf("read error dblk %d-%d\n", dblk, 189 dblk + maxsecs - 1); 190 #endif 191 if (--retries >= 0) 192 continue; 193 return (-1); /* XXX cannot output here if 194 * (cold) */ 195 } 196 if (!cold) { 197 ra_dev = d->dev; 198 ra_first = dblk; 199 ra_end = dblk + nsec; 200 diskbuf_user = &ra_dev; 201 } 202 } else /* can take blocks from end of read-ahead 203 * buffer */ 204 nsec = ra_end - dblk; 205 206 if (!cold) { 207 /* copy data from read-ahead to user buffer */ 208 if (nsec > num) 209 nsec = num; 210 memcpy(buf, 211 diskbuf + (dblk - ra_first) * BIOSDISK_SECSIZE, 212 nsec * BIOSDISK_SECSIZE); 213 } 214 buf += nsec * BIOSDISK_SECSIZE; 215 num -= nsec; 216 dblk += nsec; 217 } 218 219 return (0); 220 } 221