biosdisk_ll.c revision 1.6
1 /* $NetBSD: biosdisk_ll.c,v 1.6 1999/03/08 00:09:25 fvdl 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 void get_diskinfo __P((struct biosdisk_ll *)); 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 #define SPT(di) ((di)&0xff) 58 #define HEADS(di) ((((di)>>8)&0xff)+1) 59 #define CYL(di) 60 61 #ifndef BIOSDISK_RETRIES 62 #define BIOSDISK_RETRIES 5 63 #endif 64 65 int 66 set_geometry(d, ed) 67 struct biosdisk_ll *d; 68 struct biosdisk_ext13info *ed; 69 { 70 d->sec = d->head = 0; 71 72 get_diskinfo(d); 73 74 d->flags = 0; 75 if ((d->dev&0x80) && int13_extension(d->dev)) { 76 d->flags |= BIOSDISK_EXT13; 77 if (ed != NULL) 78 int13_getextinfo(d->dev, ed); 79 } 80 81 /* 82 * get_diskinfo assumes floppy if BIOS call fails. Check at least 83 * "valid" geometry. 84 */ 85 return (!d->sec || !d->head || !d->cyl); 86 } 87 88 /* 89 * Global shared "diskbuf" is used as read ahead buffer. For reading from 90 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 91 * this buffer doesn't cross a 64K DMA boundary. 92 */ 93 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 94 static int ra_dev; 95 static int ra_end; 96 static int ra_first; 97 98 static int 99 do_read(d, dblk, num, buf) 100 struct biosdisk_ll *d; 101 int dblk, num; 102 char *buf; 103 { 104 int cyl, head, sec, nsec, spc; 105 struct { 106 int8_t size; 107 int8_t resvd; 108 int16_t cnt; 109 int16_t off; 110 int16_t seg; 111 int64_t sec; 112 } ext; 113 114 if (d->flags & BIOSDISK_EXT13) { 115 ext.size = sizeof(ext); 116 ext.resvd = 0; 117 ext.cnt = num; 118 ext.off = (int32_t)buf; 119 ext.seg = ourseg; 120 ext.sec = dblk; 121 122 if (biosextread(d->dev, &ext)) 123 return -1; 124 125 return ext.cnt; 126 } else { 127 spc = (d->head + 1) * d->sec; 128 cyl = dblk / spc; 129 head = (dblk % spc) / d->sec; 130 sec = dblk % d->sec; 131 nsec = d->sec - sec; 132 133 if (nsec > num) 134 nsec = num; 135 136 if (biosread(d->dev, cyl, head, sec, nsec, buf)) 137 return -1; 138 139 return nsec; 140 } 141 } 142 143 int 144 readsects(d, dblk, num, buf, cold) /* reads ahead if (!cold) */ 145 struct biosdisk_ll *d; 146 int dblk, num; 147 char *buf; 148 int cold; /* don't use data segment or bss, don't call 149 * library functions */ 150 { 151 while (num) { 152 int nsec; 153 154 /* check for usable data in read-ahead buffer */ 155 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 156 || dblk < ra_first || dblk >= ra_end) { 157 158 /* no, read from disk */ 159 char *trbuf; 160 int retries = BIOSDISK_RETRIES; 161 162 nsec = num; 163 164 if (cold) { 165 /* transfer directly to buffer */ 166 trbuf = buf; 167 } else { 168 /* fill read-ahead buffer */ 169 trbuf = diskbuf; 170 if (nsec > RA_SECTORS) 171 nsec = RA_SECTORS; 172 173 } 174 175 while ((nsec = do_read(d, dblk, nsec, trbuf)) < 0) { 176 #ifdef DISK_DEBUG 177 if (!cold) 178 printf("read error C:%d H:%d S:%d-%d\n", 179 cyl, head, sec, sec + nsec - 1); 180 #endif 181 if (--retries >= 0) 182 continue; 183 if (!cold) 184 diskbuf_user = 0; /* mark invalid */ 185 return (-1); /* XXX cannot output here if 186 * (cold) */ 187 } 188 if (!cold) { 189 ra_dev = d->dev; 190 ra_first = dblk; 191 ra_end = dblk + nsec; 192 diskbuf_user = &ra_dev; 193 } 194 } else /* can take blocks from end of read-ahead 195 * buffer */ 196 nsec = ra_end - dblk; 197 198 if (!cold) { 199 /* copy data from read-ahead to user buffer */ 200 if (nsec > num) 201 nsec = num; 202 bcopy(diskbuf + (dblk - ra_first) * BIOSDISK_SECSIZE, 203 buf, nsec * BIOSDISK_SECSIZE); 204 } 205 buf += nsec * BIOSDISK_SECSIZE; 206 num -= nsec; 207 dblk += nsec; 208 } 209 210 return (0); 211 } 212
Indexes created Tue Sep 30 07:10:03 GMT 2025