unit.c revision 331722 
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: stable/11/sys/dev/sound/unit.c 331722 2018-03-29 02:50:57Z eadler $
27 */
28
29#include <sys/param.h>
30#include <sys/systm.h>
31
32#ifdef HAVE_KERNEL_OPTION_HEADERS
33#include "opt_snd.h"
34#endif
35
36#include <dev/sound/unit.h>
37
38/*
39 * Unit magic allocator for sound driver.
40 *
41 * 'u' = Unit of attached soundcards
42 * 'd' = Device type
43 * 'c' = Channel number
44 *
45 * eg: dsp0.p1  - u=0, d=p, c=1
46 *     dsp1.vp0 - u=1, d=vp, c=0
47 *     dsp0.10  - u=0, d=clone, c=allocated clone (see further explanation)
48 *
49 * Maximum unit of soundcards can be tuned through "hw.snd.maxunit", which
50 * is between SND_UNIT_UMIN (16) and SND_UNIT_UMAX (2048). By design,
51 * maximum allowable allocated channel is 256, with exception for clone
52 * devices which doesn't have any notion of channel numbering. The use of
53 * channel numbering in a clone device is simply to provide uniqueness among
54 * allocated clones. This also means that the maximum allowable clonable
55 * device is largely dependant and dynamically tuned depending on
56 * hw.snd.maxunit.
57 */
58
59/* Default width */
60static int snd_u_shift = 9;	/* 0 - 0x1ff :  512 distinct soundcards   */
61static int snd_d_shift = 5;	/* 0 - 0x1f  :   32 distinct device types */
62static int snd_c_shift = 10;	/* 0 - 0x3ff : 1024 distinct channels
63					       (256 limit "by design",
64					       except for clone devices)  */
65
66static int snd_unit_initialized = 0;
67
68#ifdef SND_DIAGNOSTIC
69#define SND_UNIT_ASSERT()	do {					\
70	if (snd_unit_initialized == 0)					\
71		panic("%s(): Uninitialized sound unit!", __func__);	\
72} while (0)
73#else
74#define SND_UNIT_ASSERT()	KASSERT(snd_unit_initialized != 0,	\
75				("%s(): Uninitialized sound unit!",	\
76				__func__))
77#endif
78
79#define MKMASK(x)	((1 << snd_##x##_shift) - 1)
80
81int
82snd_max_u(void)
83{
84	SND_UNIT_ASSERT();
85
86	return (MKMASK(u));
87}
88
89int
90snd_max_d(void)
91{
92	SND_UNIT_ASSERT();
93
94	return (MKMASK(d));
95}
96
97int
98snd_max_c(void)
99{
100	SND_UNIT_ASSERT();
101
102	return (MKMASK(c));
103}
104
105int
106snd_unit2u(int unit)
107{
108	SND_UNIT_ASSERT();
109
110	return ((unit >> (snd_c_shift + snd_d_shift)) & MKMASK(u));
111}
112
113int
114snd_unit2d(int unit)
115{
116	SND_UNIT_ASSERT();
117
118	return ((unit >> snd_c_shift) & MKMASK(d));
119}
120
121int
122snd_unit2c(int unit)
123{
124	SND_UNIT_ASSERT();
125
126	return (unit & MKMASK(c));
127}
128
129int
130snd_u2unit(int u)
131{
132	SND_UNIT_ASSERT();
133
134	return ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift));
135}
136
137int
138snd_d2unit(int d)
139{
140	SND_UNIT_ASSERT();
141
142	return ((d & MKMASK(d)) << snd_c_shift);
143}
144
145int
146snd_c2unit(int c)
147{
148	SND_UNIT_ASSERT();
149
150	return (c & MKMASK(c));
151}
152
153int
154snd_mkunit(int u, int d, int c)
155{
156	SND_UNIT_ASSERT();
157
158	return ((c & MKMASK(c)) | ((d & MKMASK(d)) << snd_c_shift) |
159	    ((u & MKMASK(u)) << (snd_c_shift + snd_d_shift)));
160}
161
162/*
163 * This *must* be called first before any of the functions above!!!
164 */
165void
166snd_unit_init(void)
167{
168	int i;
169
170	if (snd_unit_initialized != 0)
171		return;
172
173	snd_unit_initialized = 1;
174
175	if (getenv_int("hw.snd.maxunit", &i) != 0) {
176		if (i < SND_UNIT_UMIN)
177			i = SND_UNIT_UMIN;
178		else if (i > SND_UNIT_UMAX)
179			i = SND_UNIT_UMAX;
180		else
181			i = roundup2(i, 2);
182
183		for (snd_u_shift = 0; (i >> (snd_u_shift + 1)) != 0;
184		    snd_u_shift++)
185			;
186
187		/*
188		 * Make room for channels/clones allocation unit
189		 * to fit within 24bit MAXMINOR limit.
190		 */
191		snd_c_shift = 24 - snd_u_shift - snd_d_shift;
192	}
193
194	if (bootverbose != 0)
195		printf("%s() u=0x%08x [%d] d=0x%08x [%d] c=0x%08x [%d]\n",
196		    __func__, SND_U_MASK, snd_max_u() + 1,
197		    SND_D_MASK, snd_max_d() + 1, SND_C_MASK, snd_max_c() + 1);
198}
199