xref: /openbmc/linux/sound/pci/emu10k1/voice.c (revision 22246614)
1 /*
2  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
3  *                   Creative Labs, Inc.
4  *                   Lee Revell <rlrevell@joe-job.com>
5  *  Routines for control of EMU10K1 chips - voice manager
6  *
7  *  Rewrote voice allocator for multichannel support - rlrevell 12/2004
8  *
9  *  BUGS:
10  *    --
11  *
12  *  TODO:
13  *    --
14  *
15  *   This program is free software; you can redistribute it and/or modify
16  *   it under the terms of the GNU General Public License as published by
17  *   the Free Software Foundation; either version 2 of the License, or
18  *   (at your option) any later version.
19  *
20  *   This program is distributed in the hope that it will be useful,
21  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
22  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
23  *   GNU General Public License for more details.
24  *
25  *   You should have received a copy of the GNU General Public License
26  *   along with this program; if not, write to the Free Software
27  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
28  *
29  */
30 
31 #include <linux/time.h>
32 #include <sound/core.h>
33 #include <sound/emu10k1.h>
34 
35 /* Previously the voice allocator started at 0 every time.  The new voice
36  * allocator uses a round robin scheme.  The next free voice is tracked in
37  * the card record and each allocation begins where the last left off.  The
38  * hardware requires stereo interleaved voices be aligned to an even/odd
39  * boundary.  For multichannel voice allocation we ensure than the block of
40  * voices does not cross the 32 voice boundary.  This simplifies the
41  * multichannel support and ensures we can use a single write to the
42  * (set|clear)_loop_stop registers.  Otherwise (for example) the voices would
43  * get out of sync when pausing/resuming a stream.
44  *							--rlrevell
45  */
46 
47 static int voice_alloc(struct snd_emu10k1 *emu, int type, int number,
48 		       struct snd_emu10k1_voice **rvoice)
49 {
50 	struct snd_emu10k1_voice *voice;
51 	int i, j, k, first_voice, last_voice, skip;
52 
53 	*rvoice = NULL;
54 	first_voice = last_voice = 0;
55 	for (i = emu->next_free_voice, j = 0; j < NUM_G ; i += number, j += number) {
56 		// printk("i %d j %d next free %d!\n", i, j, emu->next_free_voice);
57 		i %= NUM_G;
58 
59 		/* stereo voices must be even/odd */
60 		if ((number == 2) && (i % 2)) {
61 			i++;
62 			continue;
63 		}
64 
65 		skip = 0;
66 		for (k = 0; k < number; k++) {
67 			voice = &emu->voices[(i+k) % NUM_G];
68 			if (voice->use) {
69 				skip = 1;
70 				break;
71 			}
72 		}
73 		if (!skip) {
74 			// printk("allocated voice %d\n", i);
75 			first_voice = i;
76 			last_voice = (i + number) % NUM_G;
77 			emu->next_free_voice = last_voice;
78 			break;
79 		}
80 	}
81 
82 	if (first_voice == last_voice)
83 		return -ENOMEM;
84 
85 	for (i = 0; i < number; i++) {
86 		voice = &emu->voices[(first_voice + i) % NUM_G];
87 		// printk("voice alloc - %i, %i of %i\n", voice->number, idx-first_voice+1, number);
88 		voice->use = 1;
89 		switch (type) {
90 		case EMU10K1_PCM:
91 			voice->pcm = 1;
92 			break;
93 		case EMU10K1_SYNTH:
94 			voice->synth = 1;
95 			break;
96 		case EMU10K1_MIDI:
97 			voice->midi = 1;
98 			break;
99 		case EMU10K1_EFX:
100 			voice->efx = 1;
101 			break;
102 		}
103 	}
104 	*rvoice = &emu->voices[first_voice];
105 	return 0;
106 }
107 
108 int snd_emu10k1_voice_alloc(struct snd_emu10k1 *emu, int type, int number,
109 			    struct snd_emu10k1_voice **rvoice)
110 {
111 	unsigned long flags;
112 	int result;
113 
114 	snd_assert(rvoice != NULL, return -EINVAL);
115 	snd_assert(number, return -EINVAL);
116 
117 	spin_lock_irqsave(&emu->voice_lock, flags);
118 	for (;;) {
119 		result = voice_alloc(emu, type, number, rvoice);
120 		if (result == 0 || type == EMU10K1_SYNTH || type == EMU10K1_MIDI)
121 			break;
122 
123 		/* free a voice from synth */
124 		if (emu->get_synth_voice) {
125 			result = emu->get_synth_voice(emu);
126 			if (result >= 0) {
127 				struct snd_emu10k1_voice *pvoice = &emu->voices[result];
128 				pvoice->interrupt = NULL;
129 				pvoice->use = pvoice->pcm = pvoice->synth = pvoice->midi = pvoice->efx = 0;
130 				pvoice->epcm = NULL;
131 			}
132 		}
133 		if (result < 0)
134 			break;
135 	}
136 	spin_unlock_irqrestore(&emu->voice_lock, flags);
137 
138 	return result;
139 }
140 
141 EXPORT_SYMBOL(snd_emu10k1_voice_alloc);
142 
143 int snd_emu10k1_voice_free(struct snd_emu10k1 *emu,
144 			   struct snd_emu10k1_voice *pvoice)
145 {
146 	unsigned long flags;
147 
148 	snd_assert(pvoice != NULL, return -EINVAL);
149 	spin_lock_irqsave(&emu->voice_lock, flags);
150 	pvoice->interrupt = NULL;
151 	pvoice->use = pvoice->pcm = pvoice->synth = pvoice->midi = pvoice->efx = 0;
152 	pvoice->epcm = NULL;
153 	snd_emu10k1_voice_init(emu, pvoice->number);
154 	spin_unlock_irqrestore(&emu->voice_lock, flags);
155 	return 0;
156 }
157 
158 EXPORT_SYMBOL(snd_emu10k1_voice_free);
159