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
16#include <asm/system.h>
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	(sizeof(sine_data)/sizeof(sine_data[0]))
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 */
34
35#define MAX_PERIOD	(65535)
36
37
38    /*
39     *	Current period (set by dmasound.c)
40     */
41
42unsigned short amiga_audio_period = MAX_PERIOD;
43
44static unsigned long clock_constant;
45
46void __init amiga_init_sound(void)
47{
48	static struct resource beep_res = { .name = "Beep" };
49
50	snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res);
51	if (!snd_data) {
52		printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n");
53		return;
54	}
55	memcpy (snd_data, sine_data, sizeof(sine_data));
56
57	/* setup divisor */
58	clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
59
60	/* without amifb, turn video off and enable high quality sound */
61#ifndef CONFIG_FB_AMIGA
62	amifb_video_off();
63#endif
64}
65
66static void nosound( unsigned long ignored );
67static DEFINE_TIMER(sound_timer, nosound, 0, 0);
68
69void amiga_mksound( unsigned int hz, unsigned int ticks )
70{
71	unsigned long flags;
72
73	if (!snd_data)
74		return;
75
76	local_irq_save(flags);
77	del_timer( &sound_timer );
78
79	if (hz > 20 && hz < 32767) {
80		unsigned long period = (clock_constant / hz);
81
82		if (period < amiga_audio_min_period)
83			period = amiga_audio_min_period;
84		if (period > MAX_PERIOD)
85			period = MAX_PERIOD;
86
87		/* setup pointer to data, period, length and volume */
88		custom.aud[2].audlc = snd_data;
89		custom.aud[2].audlen = sizeof(sine_data)/2;
90		custom.aud[2].audper = (unsigned short)period;
91		custom.aud[2].audvol = 32; /* 50% of maxvol */
92
93		if (ticks) {
94			sound_timer.expires = jiffies + ticks;
95			add_timer( &sound_timer );
96		}
97
98		/* turn on DMA for audio channel 2 */
99		custom.dmacon = DMAF_SETCLR | DMAF_AUD2;
100
101	} else
102		nosound( 0 );
103
104	local_irq_restore(flags);
105}
106
107
108static void nosound( unsigned long ignored )
109{
110	/* turn off DMA for audio channel 2 */
111	custom.dmacon = DMAF_AUD2;
112	/* restore period to previous value after beeping */
113	custom.aud[2].audper = amiga_audio_period;
114}
115