cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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amisound.c (2792B)

      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(struct timer_list *unused);
     69static DEFINE_TIMER(sound_timer, nosound);
     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(struct timer_list *unused)
    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}