unit.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2007 Ariff Abdullah <ariff@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
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.
15 *
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
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: stable/11/sys/dev/sound/unit.c 330897 2018-03-14 03:19:51Z eadler $
29 */
30
31#include <sys/param.h>
32#include <sys/systm.h>
33
34#ifdef HAVE_KERNEL_OPTION_HEADERS
35#include "opt_snd.h"
36#endif
37
38#include <dev/sound/unit.h>
39
40/*
41 * Unit magic allocator for sound driver.
42 *
43 * 'u' = Unit of attached soundcards
44 * 'd' = Device type
45 * 'c' = Channel number
46 *
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)
50 *
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
58 * hw.snd.maxunit.
59 */
60
61/* Default width */
62static int snd_u_shift = 9;	/* 0 - 0x1ff :  512 distinct soundcards   */
63static int snd_d_shift = 5;	/* 0 - 0x1f  :   32 distinct device types */
64static int snd_c_shift = 10;	/* 0 - 0x3ff : 1024 distinct channels
65					       (256 limit "by design",
66					       except for clone devices)  */
67
68static int snd_unit_initialized = 0;
69
70#ifdef SND_DIAGNOSTIC
71#define SND_UNIT_ASSERT()	do {					\
72	if (snd_unit_initialized == 0)					\
73		panic("%s(): Uninitialized sound unit!", __func__);	\
74} while (0)
75#else
76#define SND_UNIT_ASSERT()	KASSERT(snd_unit_initialized != 0,	\
77				("%s(): Uninitialized sound unit!",	\
78				__func__))
79#endif
80
81#define MKMASK(x)	((1 << snd_##x##_shift) - 1)
82
83int
84snd_max_u(void)
85{
86	SND_UNIT_ASSERT();
87
88	return (MKMASK(u));
89}
90
91int
92snd_max_d(void)
93{
94	SND_UNIT_ASSERT();
95
96	return (MKMASK(d));
97}
98
99int
100snd_max_c(void)
101{
102	SND_UNIT_ASSERT();
103
104	return (MKMASK(c));
105}
106
107int
108snd_unit2u(int unit)
109{
110	SND_UNIT_ASSERT();
111
112	return ((unit >> (snd_c_shift + snd_d_shift)) & MKMASK(u));
113}
114
115int
116snd_unit2d(int unit)
117{
118	SND_UNIT_ASSERT();
119
120	return ((unit >> snd_c_shift) & MKMASK(d));
121}
122
123int
124snd_unit2c(int unit)
125{
126	SND_UNIT_ASSERT();
127
128	return (unit & MKMASK(c));
129}
130
131int
132snd_u2unit(int u)
133{
134	SND_UNIT_ASSERT();
135
136	return ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift));
137}
138
139int
140snd_d2unit(int d)
141{
142	SND_UNIT_ASSERT();
143
144	return ((d & MKMASK(d)) << snd_c_shift);
145}
146
147int
148snd_c2unit(int c)
149{
150	SND_UNIT_ASSERT();
151
152	return (c & MKMASK(c));
153}
154
155int
156snd_mkunit(int u, int d, int c)
157{
158	SND_UNIT_ASSERT();
159
160	return ((c & MKMASK(c)) | ((d & MKMASK(d)) << snd_c_shift) |
161	    ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift)));
162}
163
164/*
165 * This *must* be called first before any of the functions above!!!
166 */
167void
168snd_unit_init(void)
169{
170	int i;
171
172	if (snd_unit_initialized != 0)
173		return;
174
175	snd_unit_initialized = 1;
176
177	if (getenv_int("hw.snd.maxunit", &i) != 0) {
178		if (i < SND_UNIT_UMIN)
179			i = SND_UNIT_UMIN;
180		else if (i > SND_UNIT_UMAX)
181			i = SND_UNIT_UMAX;
182		else
183			i = roundup2(i, 2);
184
185		for (snd_u_shift = 0; (i >> (snd_u_shift + 1)) != 0;
186		    snd_u_shift++)
187			;
188
189		/*
190		 * Make room for channels/clones allocation unit
191		 * to fit within 24bit MAXMINOR limit.
192		 */
193		snd_c_shift = 24 - snd_u_shift - snd_d_shift;
194	}
195
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);
200}
201