2 * linux/arch/m68k/amiga/amisound.c
4 * amiga sound driver for Linux/m68k
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
11 #include <linux/config.h>
12 #include <linux/sched.h>
13 #include <linux/timer.h>
14 #include <linux/init.h>
16 #include <asm/system.h>
17 #include <asm/amigahw.h>
19 static u_short
*snd_data
= NULL
;
20 static 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
24 #define DATA_SIZE (sizeof(sine_data)/sizeof(sine_data[0]))
27 * The minimum period for audio may be modified by the frame buffer
28 * device since it depends on htotal (for OCS/ECS/AGA)
31 volatile u_short amiga_audio_min_period
= 124; /* Default for pre-OCS */
33 #define MAX_PERIOD (65535)
37 * Current period (set by dmasound.c)
40 u_short amiga_audio_period
= MAX_PERIOD
;
42 static u_long clock_constant
;
44 void __init
amiga_init_sound(void)
46 static struct resource beep_res
= { "Beep" };
48 snd_data
= amiga_chip_alloc_res(sizeof(sine_data
), &beep_res
);
50 printk (KERN_CRIT
"amiga init_sound: failed to allocate chipmem\n");
53 memcpy (snd_data
, sine_data
, sizeof(sine_data
));
56 clock_constant
= (amiga_colorclock
+DATA_SIZE
/2)/DATA_SIZE
;
58 /* without amifb, turn video off and enable high quality sound */
59 #ifndef CONFIG_FB_AMIGA
64 static void nosound( unsigned long ignored
);
65 static struct timer_list sound_timer
= { function
: nosound
};
67 void amiga_mksound( unsigned int hz
, unsigned int ticks
)
76 del_timer( &sound_timer
);
78 if (hz
> 20 && hz
< 32767) {
79 u_long period
= (clock_constant
/ hz
);
81 if (period
< amiga_audio_min_period
)
82 period
= amiga_audio_min_period
;
83 if (period
> MAX_PERIOD
)
86 /* setup pointer to data, period, length and volume */
87 custom
.aud
[2].audlc
= snd_data
;
88 custom
.aud
[2].audlen
= sizeof(sine_data
)/2;
89 custom
.aud
[2].audper
= (u_short
)period
;
90 custom
.aud
[2].audvol
= 32; /* 50% of maxvol */
93 sound_timer
.expires
= jiffies
+ ticks
;
94 add_timer( &sound_timer
);
97 /* turn on DMA for audio channel 2 */
98 custom
.dmacon
= DMAF_SETCLR
| DMAF_AUD2
;
100 restore_flags(flags
);
104 restore_flags(flags
);
110 static void nosound( unsigned long ignored
)
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
;