AICA MIDI out support

Author: tsowell

kernel/arch/dreamcast/include/dc/sound/midi.h

@@ -0,0 +1,25 @@
+/* KallistiOS ##version##
+
+   dc/sound/midi.h
+   Copyright (C) 2020 Thomas Sowell
+
+*/
+
+/** \file   dc/sound/midi.h
+    \brief  MIDI support.
+
+    \author Thomas Sowell
+*/
+
+#ifndef __DC_SOUND_MIDI_H
+#define __DC_SOUND_MIDI_H
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+void snd_midi(uint8 midi);
+
+__END_DECLS
+
+#endif  /* __DC_SOUND_MIDI_H */

kernel/arch/dreamcast/sound/Makefile

@@ -4,7 +4,7 @@
 # (c)2001 Dan Potter
 #
 
-OBJS = snd_iface.o snd_sfxmgr.o snd_stream.o snd_stream_drv.o snd_mem.o
+OBJS = snd_iface.o snd_sfxmgr.o snd_stream.o snd_stream_drv.o snd_mem.o snd_midi.o
 
 # Only compile this if we have an ARM compiler handy
 ifdef DC_ARM_CC

kernel/arch/dreamcast/sound/arm/aica_cmd_iface.h

@@ -67,11 +67,18 @@ typedef struct aica_channel {
     aica_channel_t  * CHANR = (aica_channel_t *)(CMDR->cmd_data);
 #define AICA_CMDSTR_CHANNEL_SIZE    ((sizeof(aica_cmd_t) + sizeof(aica_channel_t))/4)
 
+#define AICA_CMDSTR_MIDI(T, CMDR, MIDIR) \
+    uint8   T[sizeof(aica_cmd_t) + sizeof(uint32)]; \
+    aica_cmd_t  * CMDR = (aica_cmd_t *)T; \
+    uint32 * MIDIR = (uint32 *)(CMDR->cmd_data);
+#define AICA_CMDSTR_MIDI_SIZE     ((sizeof(aica_cmd_t) + sizeof(uint32))/4)
+
 /* Command values (for aica_cmd_t) */
 #define AICA_CMD_NONE       0x00000000  /* No command (dummy packet)    */
 #define AICA_CMD_PING       0x00000001  /* Check for signs of life  */
 #define AICA_CMD_CHAN       0x00000002  /* Perform a wavetable action   */
 #define AICA_CMD_SYNC_CLOCK 0x00000003  /* Reset the millisecond clock  */
+#define AICA_CMD_MIDI       0x00000004
 
 /* Response values (for aica_cmd_t) */
 #define AICA_RESP_NONE      0x00000000

kernel/arch/dreamcast/sound/arm/main.c

@@ -127,6 +127,10 @@ uint32 process_one(uint32 tail) {
             /* Reset our timer clock to zero */
             timer = 0;
             break;
+        case AICA_CMD_MIDI:
+	    while ((SNDREG32(0x2808) & 0x1000) == 0x1000);
+	    SNDREG32(0x280C) = ((uint32 *)pkt->cmd_data)[0] & 0x000000FF;
+            break;
         default:
             /* error */
             break;

kernel/arch/dreamcast/sound/snd_midi.c

@@ -0,0 +1,14 @@
+#include <dc/sound/sound.h>
+#include <dc/sound/midi.h>
+
+#include "arm/aica_cmd_iface.h"
+
+void snd_midi(uint8 midi) {
+	AICA_CMDSTR_MIDI(tmp, cmd, cmdmidi);
+
+	cmd->cmd = AICA_CMD_MIDI;
+	cmd->timestamp = 0;
+	cmd->size = AICA_CMDSTR_MIDI_SIZE;
+	*cmdmidi = midi;
+	snd_sh4_to_aica(tmp, cmd->size);
+}