FreeBSD/Linux Kernel Cross Reference
sys/dev/sound/unit.c
1 /*-
2 * Copyright (c) 2007 Ariff Abdullah <ariff@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31
32 #include <dev/sound/unit.h>
33
34 /*
35 * Unit magic allocator for sound driver.
36 *
37 * 'u' = Unit of attached soundcards
38 * 'd' = Device type
39 * 'c' = Channel number
40 *
41 * eg: dsp0.p1 - u=0, d=p, c=1
42 * dsp1.vp0 - u=1, d=vp, c=0
43 * dsp0.10 - u=0, d=clone, c=allocated clone (see further explanation)
44 *
45 * Maximum unit of soundcards can be tuned through "hw.snd.maxunit", which
46 * is between SND_UNIT_UMIN (16) and SND_UNIT_UMAX (2048). By design,
47 * maximum allowable allocated channel is 256, with exception for clone
48 * devices which doesn't have any notion of channel numbering. The use of
49 * channel numbering in a clone device is simply to provide uniqueness among
50 * allocated clones. This also means that the maximum allowable clonable
51 * device is largely dependant and dynamically tuned depending on
52 * hw.snd.maxunit.
53 */
54
55 /* Default width */
56 static int snd_u_shift = 9; /* 0 - 0x1ff : 512 distinct soundcards */
57 static int snd_d_shift = 5; /* 0 - 0x1f : 32 distinct device types */
58 static int snd_c_shift = 10; /* 0 - 0x3ff : 1024 distinct channels
59 (256 limit "by design",
60 except for clone devices) */
61
62 static int snd_unit_initialized = 0;
63
64 #ifdef SND_DIAGNOSTIC
65 #define SND_UNIT_ASSERT() do { \
66 if (snd_unit_initialized == 0) \
67 panic("%s(): Uninitialized sound unit!", __func__); \
68 } while(0)
69 #else
70 #define SND_UNIT_ASSERT() KASSERT(snd_unit_initialized != 0, \
71 ("%s(): Uninitialized sound unit!", \
72 __func__))
73 #endif
74
75 #define MKMASK(x) ((1 << snd_##x##_shift) - 1)
76
77 int
78 snd_max_u(void)
79 {
80 SND_UNIT_ASSERT();
81
82 return (MKMASK(u));
83 }
84
85 int
86 snd_max_d(void)
87 {
88 SND_UNIT_ASSERT();
89
90 return (MKMASK(d));
91 }
92
93 int
94 snd_max_c(void)
95 {
96 SND_UNIT_ASSERT();
97
98 return (MKMASK(c));
99 }
100
101 int
102 snd_unit2u(int unit)
103 {
104 SND_UNIT_ASSERT();
105
106 return ((unit >> (snd_c_shift + snd_d_shift)) & MKMASK(u));
107 }
108
109 int
110 snd_unit2d(int unit)
111 {
112 SND_UNIT_ASSERT();
113
114 return ((unit >> snd_c_shift) & MKMASK(d));
115 }
116
117 int
118 snd_unit2c(int unit)
119 {
120 SND_UNIT_ASSERT();
121
122 return (unit & MKMASK(c));
123 }
124
125 int
126 snd_u2unit(int u)
127 {
128 SND_UNIT_ASSERT();
129
130 return ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift));
131 }
132
133 int
134 snd_d2unit(int d)
135 {
136 SND_UNIT_ASSERT();
137
138 return ((d & MKMASK(d)) << snd_c_shift);
139 }
140
141 int
142 snd_c2unit(int c)
143 {
144 SND_UNIT_ASSERT();
145
146 return (c & MKMASK(c));
147 }
148
149 int
150 snd_mkunit(int u, int d, int c)
151 {
152 SND_UNIT_ASSERT();
153
154 return ((c & MKMASK(c)) | ((d & MKMASK(d)) << snd_c_shift) |
155 ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift)));
156 }
157
158 /*
159 * This *must* be called first before any of the functions above!!!
160 */
161 void
162 snd_unit_init(void)
163 {
164 int i;
165
166 if (snd_unit_initialized != 0)
167 return;
168
169 snd_unit_initialized = 1;
170
171 if (getenv_int("hw.snd.maxunit", &i) != 0) {
172 if (i < SND_UNIT_UMIN)
173 i = SND_UNIT_UMIN;
174 else if (i > SND_UNIT_UMAX)
175 i = SND_UNIT_UMAX;
176 else
177 i = roundup2(i, 2);
178
179 for (snd_u_shift = 0; (i >> (snd_u_shift + 1)) != 0;
180 snd_u_shift++)
181 ;
182
183 /*
184 * Make room for channels/clones allocation unit
185 * to fit within 24bit MAXMINOR limit.
186 */
187 snd_c_shift = 24 - snd_u_shift - snd_d_shift;
188 }
189
190 if (bootverbose != 0)
191 printf("%s() u=0x%08x [%d] d=0x%08x [%d] c=0x%08x [%d]\n",
192 __func__, SND_U_MASK, snd_max_u() + 1,
193 SND_D_MASK, snd_max_d() + 1, SND_C_MASK, snd_max_c() + 1);
194 }
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