From dd4974a47c99833efc50751ced2d577b32d109d2 Mon Sep 17 00:00:00 2001
From: niklas <niklas@openbsd.org>
Date: Sun, 14 Jan 1996 16:05:23 +0000
Subject: [PATCH] Add hooks for custom audio players.  This is the original
 untouched kernel diffs from Tim Newsham <newsham@hookomo.aloha.net> found in
 his well-known audio LKM kit.

---
 sys/arch/amiga/amiga/cc.c | 55 ++++++++++++++++++++++++++-------------
 sys/arch/amiga/amiga/cc.h |  2 ++
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/sys/arch/amiga/amiga/cc.c b/sys/arch/amiga/amiga/cc.c
index 2d2ba1aa5d8..1bf1b4c6d8a 100644
--- a/sys/arch/amiga/amiga/cc.c
+++ b/sys/arch/amiga/amiga/cc.c
@@ -323,12 +323,13 @@ copper_handler()
  */
 
 struct audio_channel {
-	u_short  play_count;
+	u_short  play_count;		/* number of times to loop sample */
+	handler_func_t handler;		/* interupt handler for channel */
 };
 
 /* - channel[4] */
 /* the data for each audio channel and what to do with it. */
-static struct audio_channel channel[4];
+struct audio_channel channel[4];
 
 /* audio vbl node for vbl function  */
 struct vbl_node audio_vbl_node;    
@@ -337,6 +338,7 @@ void
 cc_init_audio()
 {
 	int i;
+	extern int defchannel_handler();
 
 	/*
 	 * disable all audio interupts
@@ -346,8 +348,10 @@ cc_init_audio()
 	/*
 	 * initialize audio channels to off.
 	 */
-	for (i=0; i < 4; i++)
+	for (i=0; i < 4; i++) {
 		channel[i].play_count = 0;
+		channel[i].handler = defchannel_handler;
+	}
 }
 
 
@@ -393,22 +397,14 @@ audio_handler()
 		if ((ir & (flag << 7)) == 0)
 			continue;
 
-		if (channel[i].play_count)
-			channel[i].play_count--;
-		else {
-			/*
-			 * disable DMA to this channel and
-			 * disable interrupts to this channel
-			 */
-			custom.dmacon = flag;
-			custom.intena = (flag << 7);
-		}
+		if (channel[i].handler)
+			channel[i].handler(i);
+
 		/*
 		 * clear this channels interrupt.
 		 */
 		custom.intreq = (flag << 7);
 	}
-
 out:
 	/*
 	 * enable audio interupts with dma still set.
@@ -418,6 +414,26 @@ out:
 	custom.intena = INTF_SETCLR | (audio_dma << 7);
 }
 
+/*
+ * this is the channel handler used by the system
+ * other software modules are free to install their own
+ * handler
+ */
+defchannel_handler(i)
+	int i;
+{
+	if (channel[i].play_count)
+		channel[i].play_count--;
+	else {
+		/*
+		 * disable DMA to this channel and
+		 * disable interrupts to this channel
+		 */
+		custom.dmacon = (1 << i);
+		custom.intena = (1 << (i + 7));
+	}
+}
+
 void
 play_sample(len, data, period, volume, channels, count)
 	u_short len, *data, period, volume, channels;
@@ -430,13 +446,16 @@ play_sample(len, data, period, volume, channels, count)
 
 	/* load the channels */
 	for (ch = 0; ch < 4; ch++) {
-		if ((dmabits & (ch << ch)) == 0)
+		if ((dmabits & (1 << ch)) == 0)
 			continue;
-		custom.aud[ch].len = len;
-		custom.aud[ch].lc = data;
+		/* busy */
+		if (channel[ch].handler != defchannel_handler)
+			continue;
+		channel[ch].play_count = count;
 		custom.aud[ch].per = period;
 		custom.aud[ch].vol = volume;
-		channel[ch].play_count = count;
+		custom.aud[ch].len = len;
+		custom.aud[ch].lc = data;
 	}
 	/*
 	 * turn on interrupts and enable dma for channels and
diff --git a/sys/arch/amiga/amiga/cc.h b/sys/arch/amiga/amiga/cc.h
index 3b85f8fddba..29464e78142 100644
--- a/sys/arch/amiga/amiga/cc.h
+++ b/sys/arch/amiga/amiga/cc.h
@@ -147,6 +147,8 @@ vm_offset_t chipmem_end;
 #define CHIPMEMTOP	(0x00200000)
 #define NCHIPMEMPG	btoc(CHIPMEMTOP - CHIPMEMBASE)
 
+typedef int (*handler_func_t)();
+
 /*
  * Prototypes.
  */
-- 
2.20.1