2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2007 Ariff Abdullah <ariff@FreeBSD.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/param.h>
32 #include <sys/systm.h>
34 #ifdef HAVE_KERNEL_OPTION_HEADERS
38 #include <dev/sound/unit.h>
41 * Unit magic allocator for sound driver.
43 * 'u' = Unit of attached soundcards
45 * 'c' = Channel number
47 * eg: dsp0.p1 - u=0, d=p, c=1
48 * dsp1.vp0 - u=1, d=vp, c=0
49 * dsp0.10 - u=0, d=clone, c=allocated clone (see further explanation)
51 * Maximum unit of soundcards can be tuned through "hw.snd.maxunit", which
52 * is between SND_UNIT_UMIN (16) and SND_UNIT_UMAX (2048). By design,
53 * maximum allowable allocated channel is 256, with exception for clone
54 * devices which doesn't have any notion of channel numbering. The use of
55 * channel numbering in a clone device is simply to provide uniqueness among
56 * allocated clones. This also means that the maximum allowable clonable
57 * device is largely dependant and dynamically tuned depending on
62 static int snd_u_shift = 9; /* 0 - 0x1ff : 512 distinct soundcards */
63 static int snd_d_shift = 5; /* 0 - 0x1f : 32 distinct device types */
64 static int snd_c_shift = 10; /* 0 - 0x3ff : 1024 distinct channels
65 (256 limit "by design",
66 except for clone devices) */
68 static int snd_unit_initialized = 0;
71 #define SND_UNIT_ASSERT() do { \
72 if (snd_unit_initialized == 0) \
73 panic("%s(): Uninitialized sound unit!", __func__); \
76 #define SND_UNIT_ASSERT() KASSERT(snd_unit_initialized != 0, \
77 ("%s(): Uninitialized sound unit!", \
81 #define MKMASK(x) ((1 << snd_##x##_shift) - 1)
112 return ((unit >> (snd_c_shift + snd_d_shift)) & MKMASK(u));
120 return ((unit >> snd_c_shift) & MKMASK(d));
128 return (unit & MKMASK(c));
136 return ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift));
144 return ((d & MKMASK(d)) << snd_c_shift);
152 return (c & MKMASK(c));
156 snd_mkunit(int u, int d, int c)
160 return ((c & MKMASK(c)) | ((d & MKMASK(d)) << snd_c_shift) |
161 ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift)));
165 * This *must* be called first before any of the functions above!!!
172 if (snd_unit_initialized != 0)
175 snd_unit_initialized = 1;
177 if (getenv_int("hw.snd.maxunit", &i) != 0) {
178 if (i < SND_UNIT_UMIN)
180 else if (i > SND_UNIT_UMAX)
185 for (snd_u_shift = 0; (i >> (snd_u_shift + 1)) != 0;
190 * Make room for channels/clones allocation unit
191 * to fit within 24bit MAXMINOR limit.
193 snd_c_shift = 24 - snd_u_shift - snd_d_shift;
196 if (bootverbose != 0)
197 printf("%s() u=0x%08x [%d] d=0x%08x [%d] c=0x%08x [%d]\n",
198 __func__, SND_U_MASK, snd_max_u() + 1,
199 SND_D_MASK, snd_max_d() + 1, SND_C_MASK, snd_max_c() + 1);