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
19#include "amiga.h"
20
21static unsigned short *snd_data;
22static const signed char sine_data[] = {
23	0,  39,  75,  103,  121,  127,  121,  103,  75,  39,
24	0, -39, -75, -103, -121, -127, -121, -103, -75, -39
25};
26#define DATA_SIZE	ARRAY_SIZE(sine_data)
27
28#define custom amiga_custom
29
30    /*
31     * The minimum period for audio may be modified by the frame buffer
32     * device since it depends on htotal (for OCS/ECS/AGA)
33     */
34
35volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */
36EXPORT_SYMBOL(amiga_audio_min_period);
37
38#define MAX_PERIOD	(65535)
39
40
41    /*
42     *	Current period (set by dmasound.c)
43     */
44
45unsigned short amiga_audio_period = MAX_PERIOD;
46EXPORT_SYMBOL(amiga_audio_period);
47
48static unsigned long clock_constant;
49
50void __init amiga_init_sound(void)
51{
52	static struct resource beep_res = { .name = "Beep" };
53
54	snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res);
55	if (!snd_data) {
56		pr_crit("amiga init_sound: failed to allocate chipmem\n");
57		return;
58	}
59	memcpy (snd_data, sine_data, sizeof(sine_data));
60
61	/* setup divisor */
62	clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
63
64	/* without amifb, turn video off and enable high quality sound */
65#ifndef CONFIG_FB_AMIGA
66	amifb_video_off();
67#endif
68}
69
70static void nosound(struct timer_list *unused);
71static DEFINE_TIMER(sound_timer, nosound);
72
73void amiga_mksound( unsigned int hz, unsigned int ticks )
74{
75	unsigned long flags;
76
77	if (!snd_data)
78		return;
79
80	local_irq_save(flags);
81	del_timer( &sound_timer );
82
83	if (hz > 20 && hz < 32767) {
84		unsigned long period = (clock_constant / hz);
85
86		if (period < amiga_audio_min_period)
87			period = amiga_audio_min_period;
88		if (period > MAX_PERIOD)
89			period = MAX_PERIOD;
90
91		/* setup pointer to data, period, length and volume */
92		custom.aud[2].audlc = snd_data;
93		custom.aud[2].audlen = sizeof(sine_data)/2;
94		custom.aud[2].audper = (unsigned short)period;
95		custom.aud[2].audvol = 32; /* 50% of maxvol */
96
97		if (ticks) {
98			sound_timer.expires = jiffies + ticks;
99			add_timer( &sound_timer );
100		}
101
102		/* turn on DMA for audio channel 2 */
103		custom.dmacon = DMAF_SETCLR | DMAF_AUD2;
104
105	} else
106		nosound( 0 );
107
108	local_irq_restore(flags);
109}
110
111
112static void nosound(struct timer_list *unused)
113{
114	/* turn off DMA for audio channel 2 */
115	custom.dmacon = DMAF_AUD2;
116	/* restore period to previous value after beeping */
117	custom.aud[2].audper = amiga_audio_period;
118}
119