1 /* $NetBSD: biosdisk_ll.c,v 1.31 2011/02/21 02:58:02 jakllsch Exp $ */
2
3 /*-
4 * Copyright (c) 2005 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Bang Jun-Young.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * Copyright (c) 1996
34 * Matthias Drochner. All rights reserved.
35 * Copyright (c) 1996
36 * Perry E. Metzger. All rights reserved.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. All advertising materials mentioning features or use of this software
47 * must display the following acknowledgements:
48 * This product includes software developed for the NetBSD Project
49 * by Matthias Drochner.
50 * This product includes software developed for the NetBSD Project
51 * by Perry E. Metzger.
52 * 4. The names of the authors may not be used to endorse or promote products
53 * derived from this software without specific prior written permission.
54 *
55 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
56 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
57 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
58 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
59 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
60 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
61 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
62 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
63 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
64 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
65 */
66
67 /*
68 * shared by bootsector startup (bootsectmain) and biosdisk.c
69 * needs lowlevel parts from bios_disk.S
70 */
71
72 #include <lib/libkern/libkern.h>
73 #include <lib/libsa/stand.h>
74
75 #include "biosdisk_ll.h"
76 #include "diskbuf.h"
77 #include "libi386.h"
78
79 static int do_read(struct biosdisk_ll *, daddr_t, int, char *);
80
81 /*
82 * we get from get_diskinfo():
83 * %ah %ch %cl %dh (registers after int13/8), ie
84 * xxxxxxxx cccccccc CCssssss hhhhhhhh
85 */
86 #define STATUS(di) ((di)>>24)
87 #define SPT(di) (((di)>>8)&0x3f)
88 #define HEADS(di) (((di)&0xff)+1)
89 #define CYL(di) (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1)
90
91 #ifndef BIOSDISK_RETRIES
92 #define BIOSDISK_RETRIES 5
93 #endif
94
95 int
set_geometry(struct biosdisk_ll * d,struct biosdisk_extinfo * ed)96 set_geometry(struct biosdisk_ll *d, struct biosdisk_extinfo *ed)
97 {
98 int diskinfo;
99
100 diskinfo = biosdisk_getinfo(d->dev);
101 d->sec = SPT(diskinfo);
102 d->head = HEADS(diskinfo);
103 d->cyl = CYL(diskinfo);
104 d->chs_sectors = d->sec * d->head * d->cyl;
105
106 if (d->dev >= 0x80 + get_harddrives()) {
107 d->secsize = 2048;
108 d->type = BIOSDISK_TYPE_CD;
109 } else {
110 d->secsize = 512;
111 if (d->dev & 0x80)
112 d->type = BIOSDISK_TYPE_HD;
113 else
114 d->type = BIOSDISK_TYPE_FD;
115 }
116
117 /*
118 * Some broken BIOSes such as one found on Soltek SL-75DRV2 report
119 * that they don't support int13 extension for CD-ROM drives while
120 * they actually do. As a workaround, if the boot device is a CD we
121 * assume that the extension is available. Note that only very old
122 * BIOSes don't support the extended mode, and they don't work with
123 * ATAPI CD-ROM drives, either. So there's no problem.
124 */
125 d->flags = 0;
126 if (d->type == BIOSDISK_TYPE_CD ||
127 (d->type == BIOSDISK_TYPE_HD && biosdisk_int13ext(d->dev))) {
128 d->flags |= BIOSDISK_INT13EXT;
129 if (ed != NULL) {
130 ed->size = sizeof(*ed);
131 if (biosdisk_getextinfo(d->dev, ed) != 0)
132 return -1;
133 }
134 }
135
136 /*
137 * If the drive is 2.88MB floppy drive, check that we can actually
138 * read sector >= 18. If not, assume 1.44MB floppy disk.
139 */
140 if (d->type == BIOSDISK_TYPE_FD && SPT(diskinfo) == 36) {
141 char buf[512];
142
143 if (biosdisk_read(d->dev, 0, 0, 18, 1, buf)) {
144 d->sec = 18;
145 d->chs_sectors /= 2;
146 }
147 }
148
149 return 0;
150 }
151
152 /*
153 * Global shared "diskbuf" is used as read ahead buffer. For reading from
154 * floppies, the bootstrap has to be loaded on a 64K boundary to ensure that
155 * this buffer doesn't cross a 64K DMA boundary.
156 */
157 static int ra_dev;
158 static daddr_t ra_end;
159 static daddr_t ra_first;
160
161 /*
162 * Because some older BIOSes have bugs in their int13 extensions, we
163 * only try to use the extended read if the I/O request can't be addressed
164 * using CHS.
165 *
166 * Of course, some BIOSes have bugs in ths CHS read, such as failing to
167 * function properly if the MBR table has a different geometry than the
168 * BIOS would generate internally for the device in question, and so we
169 * provide a way to force the extended on hard disks via a compile-time
170 * option.
171 */
172 #if defined(FORCE_INT13EXT)
173 #define NEED_INT13EXT(d, dblk, num) \
174 (((d)->dev & 0x80) != 0)
175 #else
176 #define NEED_INT13EXT(d, dblk, num) \
177 (((d)->type == BIOSDISK_TYPE_CD) || \
178 ((d)->type == BIOSDISK_TYPE_HD && \
179 ((dblk) + (num)) >= (d)->chs_sectors))
180 #endif
181
182 static int
do_read(struct biosdisk_ll * d,daddr_t dblk,int num,char * buf)183 do_read(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf)
184 {
185
186 if (NEED_INT13EXT(d, dblk, num)) {
187 struct {
188 int8_t size;
189 int8_t resvd;
190 int16_t cnt;
191 int16_t off;
192 int16_t seg;
193 int64_t sec;
194 } ext;
195
196 if (!(d->flags & BIOSDISK_INT13EXT))
197 return -1;
198 ext.size = sizeof(ext);
199 ext.resvd = 0;
200 ext.cnt = num;
201 /* seg:off of physical address */
202 ext.off = (int)buf & 0xf;
203 ext.seg = vtophys(buf) >> 4;
204 ext.sec = dblk;
205
206 if (biosdisk_extread(d->dev, &ext)) {
207 (void)biosdisk_reset(d->dev);
208 return -1;
209 }
210
211 return ext.cnt;
212 } else {
213 int cyl, head, sec, nsec, spc, dblk32;
214
215 dblk32 = (int)dblk;
216 spc = d->head * d->sec;
217 cyl = dblk32 / spc;
218 head = (dblk32 % spc) / d->sec;
219 sec = dblk32 % d->sec;
220 nsec = d->sec - sec;
221
222 if (nsec > num)
223 nsec = num;
224
225 if (biosdisk_read(d->dev, cyl, head, sec, nsec, buf)) {
226 (void)biosdisk_reset(d->dev);
227 return -1;
228 }
229
230 return nsec;
231 }
232 }
233
234 /*
235 * NB if 'cold' is set below not all of the program is loaded, so
236 * mustn't use data segment, bss, call library functions or do read-ahead.
237 */
238 int
readsects(struct biosdisk_ll * d,daddr_t dblk,int num,char * buf,int cold)239 readsects(struct biosdisk_ll *d, daddr_t dblk, int num, char *buf, int cold)
240 {
241 #ifdef BOOTXX
242 #define cold 1 /* collapse out references to diskbufp */
243 #endif
244 while (num) {
245 int nsec;
246
247 /* check for usable data in read-ahead buffer */
248 if (cold || diskbuf_user != &ra_dev || d->dev != ra_dev
249 || dblk < ra_first || dblk >= ra_end) {
250
251 /* no, read from disk */
252 char *trbuf;
253 int maxsecs;
254 int retries = BIOSDISK_RETRIES;
255
256 if (cold) {
257 /* transfer directly to buffer */
258 trbuf = buf;
259 maxsecs = num;
260 } else {
261 /* fill read-ahead buffer */
262 trbuf = alloc_diskbuf(0); /* no data yet */
263 maxsecs = DISKBUFSIZE / d->secsize;
264 }
265
266 while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) {
267 #ifdef DISK_DEBUG
268 if (!cold)
269 printf("read error dblk %"PRId64"-%"PRId64"\n",
270 dblk, (dblk + maxsecs - 1));
271 #endif
272 if (--retries >= 0)
273 continue;
274 return -1; /* XXX cannot output here if
275 * (cold) */
276 }
277 if (!cold) {
278 ra_dev = d->dev;
279 ra_first = dblk;
280 ra_end = dblk + nsec;
281 diskbuf_user = &ra_dev;
282 }
283 } else /* can take blocks from end of read-ahead
284 * buffer */
285 nsec = ra_end - dblk;
286
287 if (!cold) {
288 /* copy data from read-ahead to user buffer */
289 if (nsec > num)
290 nsec = num;
291 memcpy(buf,
292 diskbufp + (dblk - ra_first) * d->secsize,
293 nsec * d->secsize);
294 }
295 buf += nsec * d->secsize;
296 num -= nsec;
297 dblk += nsec;
298 }
299
300 return 0;
301 }
302
303 /*
304 * Return the number of hard disk drives.
305 */
306 int
get_harddrives(void)307 get_harddrives(void)
308 {
309 /*
310 * Some BIOSes are buggy so that they return incorrect number
311 * of hard drives with int13/ah=8. We read a byte at 0040:0075
312 * instead, which is known to be always correct.
313 */
314 int n = 0;
315
316 pvbcopy((void *)0x475, &n, 1);
317
318 return n;
319 }
320