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116 lines
2.7 KiB
116 lines
2.7 KiB
/* |
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* linux/arch/m68k/amiga/amisound.c |
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* |
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* amiga sound driver for Linux/m68k |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file COPYING in the main directory of this archive |
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* for more details. |
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*/ |
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#include <linux/jiffies.h> |
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#include <linux/timer.h> |
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#include <linux/init.h> |
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#include <linux/string.h> |
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#include <linux/module.h> |
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#include <asm/amigahw.h> |
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static unsigned short *snd_data; |
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static const signed char sine_data[] = { |
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0, 39, 75, 103, 121, 127, 121, 103, 75, 39, |
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0, -39, -75, -103, -121, -127, -121, -103, -75, -39 |
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}; |
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#define DATA_SIZE ARRAY_SIZE(sine_data) |
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#define custom amiga_custom |
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/* |
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* The minimum period for audio may be modified by the frame buffer |
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* device since it depends on htotal (for OCS/ECS/AGA) |
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*/ |
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volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */ |
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EXPORT_SYMBOL(amiga_audio_min_period); |
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#define MAX_PERIOD (65535) |
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/* |
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* Current period (set by dmasound.c) |
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*/ |
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unsigned short amiga_audio_period = MAX_PERIOD; |
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EXPORT_SYMBOL(amiga_audio_period); |
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static unsigned long clock_constant; |
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void __init amiga_init_sound(void) |
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{ |
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static struct resource beep_res = { .name = "Beep" }; |
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snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res); |
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if (!snd_data) { |
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pr_crit("amiga init_sound: failed to allocate chipmem\n"); |
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return; |
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} |
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memcpy (snd_data, sine_data, sizeof(sine_data)); |
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/* setup divisor */ |
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clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE; |
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/* without amifb, turn video off and enable high quality sound */ |
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#ifndef CONFIG_FB_AMIGA |
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amifb_video_off(); |
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#endif |
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} |
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static void nosound(struct timer_list *unused); |
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static DEFINE_TIMER(sound_timer, nosound); |
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void amiga_mksound( unsigned int hz, unsigned int ticks ) |
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{ |
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unsigned long flags; |
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if (!snd_data) |
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return; |
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local_irq_save(flags); |
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del_timer( &sound_timer ); |
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if (hz > 20 && hz < 32767) { |
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unsigned long period = (clock_constant / hz); |
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if (period < amiga_audio_min_period) |
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period = amiga_audio_min_period; |
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if (period > MAX_PERIOD) |
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period = MAX_PERIOD; |
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/* setup pointer to data, period, length and volume */ |
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custom.aud[2].audlc = snd_data; |
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custom.aud[2].audlen = sizeof(sine_data)/2; |
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custom.aud[2].audper = (unsigned short)period; |
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custom.aud[2].audvol = 32; /* 50% of maxvol */ |
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if (ticks) { |
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sound_timer.expires = jiffies + ticks; |
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add_timer( &sound_timer ); |
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} |
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/* turn on DMA for audio channel 2 */ |
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custom.dmacon = DMAF_SETCLR | DMAF_AUD2; |
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} else |
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nosound( 0 ); |
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local_irq_restore(flags); |
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} |
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static void nosound(struct timer_list *unused) |
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{ |
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/* turn off DMA for audio channel 2 */ |
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custom.dmacon = DMAF_AUD2; |
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/* restore period to previous value after beeping */ |
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custom.aud[2].audper = amiga_audio_period; |
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}
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