biosdisk_ll.c revision 1.5
1 /* $NetBSD: biosdisk_ll.c,v 1.5 1998/10/15 15:28:22 ws 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 int int13_extension __P((int)); 52 extern int biosread __P((int, int, int, int, int, char *)); 53 extern int biosextread __P((int, void *)); 54 static int do_read __P((struct biosdisk_ll *, int, int, char *)); 55 56 #define SPT(di) ((di)&0xff) 57 #define HEADS(di) ((((di)>>8)&0xff)+1) 58 59 #ifndef BIOSDISK_RETRIES 60 #define BIOSDISK_RETRIES 5 61 #endif 62 63 int 64 set_geometry(d) 65 struct biosdisk_ll *d; 66 { 67 int diskinfo; 68 69 diskinfo = get_diskinfo(d->dev); 70 71 d->flags = 0; 72 if ((d->dev&0x80) && int13_extension(d->dev)) 73 d->flags |= BIOSDISK_EXT13; 74 75 d->spc = (d->spt = SPT(diskinfo)) * HEADS(diskinfo); 76 77 /* 78 * get_diskinfo assumes floppy if BIOS call fails. Check at least 79 * "valid" geometry. 80 */ 81 return (!d->spc || !d->spt); 82 } 83 84 /* 85 * Global shared "diskbuf" is used as read ahead buffer. For reading from 86 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that 87 * this buffer doesn't cross a 64K DMA boundary. 88 */ 89 #define RA_SECTORS (DISKBUFSIZE / BIOSDISK_SECSIZE) 90 static int ra_dev; 91 static int ra_end; 92 static int ra_first; 93 94 static int 95 do_read(d, dblk, num, buf) 96 struct biosdisk_ll *d; 97 int dblk, num; 98 char *buf; 99 { 100 int cyl, head, sec, nsec; 101 struct { 102 int8_t size; 103 int8_t resvd; 104 int16_t cnt; 105 int16_t off; 106 int16_t seg; 107 int64_t sec; 108 } ext; 109 110 if (d->flags & BIOSDISK_EXT13) { 111 ext.size = sizeof(ext); 112 ext.resvd = 0; 113 ext.cnt = num; 114 ext.off = (int32_t)buf; 115 ext.seg = ourseg; 116 ext.sec = dblk; 117 118 if (biosextread(d->dev, &ext)) 119 return -1; 120 121 return ext.cnt; 122 } else { 123 124 cyl = dblk / d->spc; 125 head = (dblk % d->spc) / d->spt; 126 sec = dblk % d->spt; 127 nsec = d->spt - sec; 128 129 if (nsec > num) 130 nsec = num; 131 132 if (biosread(d->dev, cyl, head, sec, nsec, buf)) 133 return -1; 134 135 return nsec; 136 } 137 } 138 139 int 140 readsects(d, dblk, num, buf, cold) /* reads ahead if (!cold) */ 141 struct biosdisk_ll *d; 142 int dblk, num; 143 char *buf; 144 int cold; /* don't use data segment or bss, don't call 145 * library functions */ 146 { 147 while (num) { 148 int nsec; 149 150 /* check for usable data in read-ahead buffer */ 151 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev 152 || dblk < ra_first || dblk >= ra_end) { 153 154 /* no, read from disk */ 155 char *trbuf; 156 int retries = BIOSDISK_RETRIES; 157 158 nsec = num; 159 160 if (cold) { 161 /* transfer directly to buffer */ 162 trbuf = buf; 163 } else { 164 /* fill read-ahead buffer */ 165 trbuf = diskbuf; 166 if (nsec > RA_SECTORS) 167 nsec = RA_SECTORS; 168 169 } 170 171 while ((nsec = do_read(d, dblk, nsec, trbuf)) < 0) { 172 #ifdef DISK_DEBUG 173 if (!cold) 174 printf("read error C:%d H:%d S:%d-%d\n", 175 cyl, head, sec, sec + nsec - 1); 176 #endif 177 if (--retries >= 0) 178 continue; 179 if (!cold) 180 diskbuf_user = 0; /* mark invalid */ 181 return (-1); /* XXX cannot output here if 182 * (cold) */ 183 } 184 if (!cold) { 185 ra_dev = d->dev; 186 ra_first = dblk; 187 ra_end = dblk + nsec; 188 diskbuf_user = &ra_dev; 189 } 190 } else /* can take blocks from end of read-ahead 191 * buffer */ 192 nsec = ra_end - dblk; 193 194 if (!cold) { 195 /* copy data from read-ahead to user buffer */ 196 if (nsec > num) 197 nsec = num; 198 bcopy(diskbuf + (dblk - ra_first) * BIOSDISK_SECSIZE, 199 buf, nsec * BIOSDISK_SECSIZE); 200 } 201 buf += nsec * BIOSDISK_SECSIZE; 202 num -= nsec; 203 dblk += nsec; 204 } 205 206 return (0); 207 } 208
Indexes created Tue Sep 30 11:09:46 GMT 2025