1/*
2 * linux/arch/m68k/amiga/amisound.c
3 *
4 * amiga sound driver for Linux/m68k
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License.  See the file COPYING in the main directory of this archive
8 * for more details.
9 */
10
11#include <linux/jiffies.h>
12#include <linux/timer.h>
13#include <linux/init.h>
14#include <linux/string.h>
15#include <linux/module.h>
16
17#include <asm/amigahw.h>
18
19static unsigned short *snd_data;
20static const signed char sine_data[] = {
21	0,  39,  75,  103,  121,  127,  121,  103,  75,  39,
22	0, -39, -75, -103, -121, -127, -121, -103, -75, -39
23};
24#define DATA_SIZE	ARRAY_SIZE(sine_data)
25
26#define custom amiga_custom
27
28    /*
29     * The minimum period for audio may be modified by the frame buffer
30     * device since it depends on htotal (for OCS/ECS/AGA)
31     */
32
33volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */
34EXPORT_SYMBOL(amiga_audio_min_period);
35
36#define MAX_PERIOD	(65535)
37
38
39    /*
40     *	Current period (set by dmasound.c)
41     */
42
43unsigned short amiga_audio_period = MAX_PERIOD;
44EXPORT_SYMBOL(amiga_audio_period);
45
46static unsigned long clock_constant;
47
48void __init amiga_init_sound(void)
49{
50	static struct resource beep_res = { .name = "Beep" };
51
52	snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res);
53	if (!snd_data) {
54		pr_crit("amiga init_sound: failed to allocate chipmem\n");
55		return;
56	}
57	memcpy (snd_data, sine_data, sizeof(sine_data));
58
59	/* setup divisor */
60	clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
61
62	/* without amifb, turn video off and enable high quality sound */
63#ifndef CONFIG_FB_AMIGA
64	amifb_video_off();
65#endif
66}
67
68static void nosound( unsigned long ignored );
69static DEFINE_TIMER(sound_timer, nosound, 0, 0);
70
71void amiga_mksound( unsigned int hz, unsigned int ticks )
72{
73	unsigned long flags;
74
75	if (!snd_data)
76		return;
77
78	local_irq_save(flags);
79	del_timer( &sound_timer );
80
81	if (hz > 20 && hz < 32767) {
82		unsigned long period = (clock_constant / hz);
83
84		if (period < amiga_audio_min_period)
85			period = amiga_audio_min_period;
86		if (period > MAX_PERIOD)
87			period = MAX_PERIOD;
88
89		/* setup pointer to data, period, length and volume */
90		custom.aud[2].audlc = snd_data;
91		custom.aud[2].audlen = sizeof(sine_data)/2;
92		custom.aud[2].audper = (unsigned short)period;
93		custom.aud[2].audvol = 32; /* 50% of maxvol */
94
95		if (ticks) {
96			sound_timer.expires = jiffies + ticks;
97			add_timer( &sound_timer );
98		}
99
100		/* turn on DMA for audio channel 2 */
101		custom.dmacon = DMAF_SETCLR | DMAF_AUD2;
102
103	} else
104		nosound( 0 );
105
106	local_irq_restore(flags);
107}
108
109
110static void nosound( unsigned long ignored )
111{
112	/* turn off DMA for audio channel 2 */
113	custom.dmacon = DMAF_AUD2;
114	/* restore period to previous value after beeping */
115	custom.aud[2].audper = amiga_audio_period;
116}
117