patch-1.3.94 linux/arch/m68k/amiga/amisound.c

• Lines: 111
• Date: Thu Apr 18 02:26:30 1996
• Orig file: v1.3.93/linux/arch/m68k/amiga/amisound.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/amiga/amisound.c linux/arch/m68k/amiga/amisound.c
@@ -0,0 +1,110 @@
+/*
+ * linux/amiga/amisound.c
+ *
+ * amiga sound driver for 680x0 Linux
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file README.legal in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/timer.h>
+
+#include <asm/system.h>
+#include <asm/amigahw.h>
+#include <asm/bootinfo.h>
+
+static u_short *snd_data = NULL;
+static const signed char sine_data[] = {
+	0,  39,  75,  103,  121,  127,  121,  103,  75,  39,
+	0, -39, -75, -103, -121, -127, -121, -103, -75, -39
+};
+#define DATA_SIZE	(sizeof(sine_data)/sizeof(sine_data[0]))
+
+/* Imported from arch/m68k/amiga/amifb.c */
+extern volatile u_short amiga_audio_min_period;
+
+#define MAX_PERIOD	(65535)
+
+
+    /*
+     *	Current period (set by dmasound.c)
+     */
+
+u_short amiga_audio_period = MAX_PERIOD;
+
+static u_long clock_constant;
+
+static void init_sound(void)
+{
+	snd_data = amiga_chip_alloc(sizeof(sine_data));
+	if (!snd_data) {
+		printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n");
+		return;
+	}
+	memcpy (snd_data, sine_data, sizeof(sine_data));
+
+	/* setup divisor */
+	clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
+}
+
+static void nosound( unsigned long ignored );
+static struct timer_list sound_timer = { NULL, NULL, 0, 0, nosound };
+
+void amiga_mksound( unsigned int hz, unsigned int ticks )
+{
+	static int inited = 0;
+	unsigned long flags;
+
+	if (!inited) {
+		init_sound();
+		inited = 1;
+	}
+
+	if (!snd_data)
+		return;
+
+	save_flags(flags);
+	cli();
+	del_timer( &sound_timer );
+
+	if (hz > 20 && hz < 32767) {
+		u_long period = (clock_constant / hz);
+
+		if (period < amiga_audio_min_period)
+			period = amiga_audio_min_period;
+		if (period > MAX_PERIOD)
+			period = MAX_PERIOD;
+
+		/* setup pointer to data, period, length and volume */
+		custom.aud[0].audlc = snd_data;
+		custom.aud[0].audlen = sizeof(sine_data)/2;
+		custom.aud[0].audper = (u_short)period;
+		custom.aud[0].audvol = 64; /* maxvol */
+	
+		if (ticks) {
+			sound_timer.expires = jiffies + ticks;
+			add_timer( &sound_timer );
+		}
+
+		/* turn on DMA for audio channel 0 */
+		custom.dmacon = DMAF_SETCLR | DMAF_AUD0;
+
+		restore_flags(flags);
+		return;
+	} else {
+		nosound( 0 );
+		restore_flags(flags);
+		return;
+	}
+}
+
+
+static void nosound( unsigned long ignored )
+{
+	/* turn off DMA for audio channel 0 */
+	custom.dmacon = DMAF_AUD0;
+	/* restore period to previous value after beeping */
+	custom.aud[0].audper = amiga_audio_period;
+}