2 * Copyright (c) 2011 Marius Strobl <marius@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/systm.h>
34 #include <cam/cam_ccb.h>
36 #include <machine/md_var.h>
39 scsi_da_bios_params(struct ccb_calc_geometry *ccg)
41 uint32_t secs_per_cylinder, size_mb;
44 * The VTOC8 disk label only uses 16-bit fields for cylinders, heads
45 * and sectors so the geometry of large disks has to be adjusted.
46 * We generally use the sizing used by cam_calc_geometry(9), except
47 * when it would overflow the cylinders, in which case we use 255
48 * heads and sectors. This allows disks up to the 2TB limit of the
50 * XXX this doesn't match the sizing used by OpenSolaris, as that
51 * would exceed the 8-bit ccg->heads and ccg->secs_per_track.
53 if (ccg->block_size == 0)
55 size_mb = (1024L * 1024L) / ccg->block_size;
58 size_mb = ccg->volume_size / size_mb;
59 if (ccg->volume_size > (uint64_t)65535 * 255 * 63) {
61 ccg->secs_per_track = 255;
62 } else if (size_mb > 1024) {
64 ccg->secs_per_track = 63;
67 ccg->secs_per_track = 32;
69 secs_per_cylinder = ccg->heads * ccg->secs_per_track;
70 if (secs_per_cylinder == 0)
72 ccg->cylinders = ccg->volume_size / secs_per_cylinder;