2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * Copyright (c) 2001 John H. Baldwin <jhb@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
32 * BIOS CD device handling for CD's that have been booted off of via no
33 * emulation booting as defined in the El Torito standard.
35 * Ideas and algorithms from:
37 * - FreeBSD libi386/biosdisk.c
43 #include <sys/param.h>
44 #include <machine/bootinfo.h>
48 #include <bootstrap.h>
53 #define BIOSCD_SECSIZE 2048
54 #define BUFSIZE (1 * BIOSCD_SECSIZE)
57 /* Major numbers for devices we frontend for. */
62 # define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
64 # define DEBUG(fmt, args...)
67 struct specification_packet {
73 u_short sp_devicespec;
74 u_short sp_buffersegment;
75 u_short sp_loadsegment;
76 u_short sp_sectorcount;
82 * List of BIOS devices, translation from disk unit number to
85 static struct bcinfo {
86 int bc_unit; /* BIOS unit number */
87 struct specification_packet bc_sp;
89 static int nbcinfo = 0;
91 static int bc_read(int unit, daddr_t dblk, int blks, caddr_t dest);
92 static int bc_init(void);
93 static int bc_strategy(void *devdata, int flag, daddr_t dblk,
94 size_t size, char *buf, size_t *rsize);
95 static int bc_open(struct open_file *f, ...);
96 static int bc_close(struct open_file *f);
97 static void bc_print(int verbose);
99 struct devsw bioscd = {
112 * Translate between BIOS device numbers and our private unit numbers.
115 bc_bios2unit(int biosdev)
119 DEBUG("looking for bios device 0x%x", biosdev);
120 for (i = 0; i < nbcinfo; i++) {
121 DEBUG("bc unit %d is BIOS device 0x%x", i, bcinfo[i].bc_unit);
122 if (bcinfo[i].bc_unit == biosdev)
129 bc_unit2bios(int unit)
131 if ((unit >= 0) && (unit < nbcinfo))
132 return(bcinfo[unit].bc_unit);
137 * We can't quiz, we have to be told what device to use, so this functoin
138 * doesn't do anything. Instead, the loader calls bc_add() with the BIOS
139 * device number to add.
152 if (nbcinfo >= MAXBCDEV)
154 bcinfo[nbcinfo].bc_unit = biosdev;
159 v86.ds = VTOPSEG(&bcinfo[nbcinfo].bc_sp);
160 v86.esi = VTOPOFF(&bcinfo[nbcinfo].bc_sp);
162 if ((v86.eax & 0xff00) != 0)
165 printf("BIOS CD is cd%d\n", nbcinfo);
171 * Print information about disks
174 bc_print(int verbose)
179 for (i = 0; i < nbcinfo; i++) {
180 sprintf(line, " cd%d: Device 0x%x\n", i,
181 bcinfo[i].bc_sp.sp_devicespec);
187 * Attempt to open the disk described by (dev) for use by (f).
190 bc_open(struct open_file *f, ...)
193 struct i386_devdesc *dev;
196 dev = va_arg(ap, struct i386_devdesc *);
198 if (dev->d_unit >= nbcinfo) {
199 DEBUG("attempt to open nonexistent disk");
207 bc_close(struct open_file *f)
214 bc_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf,
217 struct i386_devdesc *dev;
220 #ifdef BD_SUPPORT_FRAGS
221 char fragbuf[BIOSCD_SECSIZE];
224 fragsize = size % BIOSCD_SECSIZE;
226 if (size % BIOSCD_SECSIZE)
232 dev = (struct i386_devdesc *)devdata;
234 blks = size / BIOSCD_SECSIZE;
235 if (dblk % (BIOSCD_SECSIZE / DEV_BSIZE) != 0)
237 dblk /= (BIOSCD_SECSIZE / DEV_BSIZE);
238 DEBUG("read %d from %lld to %p", blks, dblk, buf);
242 if (blks && bc_read(unit, dblk, blks, buf)) {
246 #ifdef BD_SUPPORT_FRAGS
247 DEBUG("frag read %d from %lld+%d to %p",
248 fragsize, dblk, blks, buf + (blks * BIOSCD_SECSIZE));
249 if (fragsize && bc_read(unit, dblk + blks, 1, fragbuf)) {
250 DEBUG("frag read error");
253 bcopy(fragbuf, buf + (blks * BIOSCD_SECSIZE), fragsize);
260 /* Max number of sectors to bounce-buffer at a time. */
261 #define CD_BOUNCEBUF 8
264 bc_read(int unit, daddr_t dblk, int blks, caddr_t dest)
266 u_int maxfer, resid, result, retry, x;
268 static struct edd_packet packet;
274 /* Just in case some idiot actually tries to read -1 blocks... */
278 /* If nothing to do, just return succcess. */
282 /* Decide whether we have to bounce */
283 if (VTOP(dest) >> 20 != 0) {
285 * The destination buffer is above first 1MB of
286 * physical memory so we have to arrange a suitable
289 x = min(CD_BOUNCEBUF, (unsigned)blks);
290 bbuf = alloca(x * BIOSCD_SECSIZE);
297 biosdev = bc_unit2bios(unit);
311 * Loop retrying the operation a couple of times. The BIOS
314 for (retry = 0; retry < 3; retry++) {
315 /* If retrying, reset the drive */
324 packet.len = sizeof(struct edd_packet);
326 packet.off = VTOPOFF(xp);
327 packet.seg = VTOPSEG(xp);
333 v86.ds = VTOPSEG(&packet);
334 v86.esi = VTOPOFF(&packet);
336 result = V86_CY(v86.efl);
342 error = (v86.eax >> 8) & 0xff;
344 DEBUG("%d sectors from %lld to %p (0x%x) %s", x, dblk, p,
345 VTOP(p), result ? "failed" : "ok");
346 DEBUG("unit %d status 0x%x", unit, error);
348 bcopy(bbuf, p, x * BIOSCD_SECSIZE);
349 p += (x * BIOSCD_SECSIZE);
354 /* hexdump(dest, (blks * BIOSCD_SECSIZE)); */
359 * Return a suitable dev_t value for (dev).
362 bc_getdev(struct i386_devdesc *dev)
369 biosdev = bc_unit2bios(unit);
370 DEBUG("unit %d BIOS device %d", unit, biosdev);
371 if (biosdev == -1) /* not a BIOS device */
375 * XXX: Need to examine device spec here to figure out if SCSI or
376 * ATAPI. No idea on how to figure out device number. All we can
377 * really pass to the kernel is what bus and device on which bus we
378 * were booted from, which dev_t isn't well suited to since those
379 * number don't match to unit numbers very well. We may just need
380 * to engage in a hack where we pass -C to the boot args if we are
386 /* XXX: Assume partition 'a'. */
387 rootdev = MAKEBOOTDEV(major, 0, unit, 0);
388 DEBUG("dev is 0x%x\n", rootdev);