git: 15ae481e056b - stable/13 - snd_uaudio(4): Add some examples accessing USB MIDI devices.

From: Hans Petter Selasky <hselasky_at_FreeBSD.org>
Date: Tue, 04 Oct 2022 14:50:19 UTC
The branch stable/13 has been updated by hselasky:

URL: https://cgit.FreeBSD.org/src/commit/?id=15ae481e056be4a67fa9aa5af7cbd04de2eece2b

commit 15ae481e056be4a67fa9aa5af7cbd04de2eece2b
Author:     Goran Mekic <meka@tilda.center>
AuthorDate: 2022-09-27 17:28:27 +0000
Commit:     Hans Petter Selasky <hselasky@FreeBSD.org>
CommitDate: 2022-10-04 14:40:50 +0000

    snd_uaudio(4): Add some examples accessing USB MIDI devices.
    
    Differential Revision:  https://reviews.freebsd.org/D36195
    Sponsored by:   NVIDIA Networking
    
    (cherry picked from commit f092c21bf630543dc899a444fa7885d0bbbaedfd)
---
 share/examples/Makefile        |  2 ++
 share/examples/sound/midi.c    | 76 ++++++++++++++++++++++++++++++++++++++++++
 share/examples/sound/ossmidi.h | 63 ++++++++++++++++++++++++++++++++++
 3 files changed, 141 insertions(+)

diff --git a/share/examples/Makefile b/share/examples/Makefile
index 1d916f344b77..7179f1bff1a4 100644
--- a/share/examples/Makefile
+++ b/share/examples/Makefile
@@ -320,6 +320,8 @@ SE_DIRS+=	sound
 SE_SOUND= \
 	basic.c \
 	ossinit.h \
+	ossmidi.h \
+	midi.c \
 	README
 
 SE_DIRS+=	sunrpc
diff --git a/share/examples/sound/midi.c b/share/examples/sound/midi.c
new file mode 100644
index 000000000000..fbe4d9480530
--- /dev/null
+++ b/share/examples/sound/midi.c
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 Goran Mekić
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <unistd.h>
+
+#include "ossmidi.h"
+
+int
+main()
+{
+	midi_event_t event;
+	midi_config_t midi_config;
+	int l = -1;
+	unsigned char raw;
+
+	midi_config.device = "/dev/umidi1.0";
+	oss_midi_init(&midi_config);
+
+	while ((l = read(midi_config.fd, &raw, sizeof(raw))) != -1) {
+		if (!(raw & 0x80)) {
+			continue;
+		}
+		event.type = raw & CMD_MASK;
+		event.channel = raw & CHANNEL_MASK;
+		switch (event.type) {
+		case NOTE_ON:
+		case NOTE_OFF:
+		case CONTROLER_ON:
+			if ((l = read(midi_config.fd, &(event.note), sizeof(event.note))) == -1) {
+				perror("Error reading MIDI note");
+				exit(1);
+			}
+			if ((l = read(midi_config.fd, &(event.velocity), sizeof(event.velocity))) == -1) {
+				perror("Error reading MIDI velocity");
+				exit(1);
+			}
+			break;
+		}
+		switch (event.type) {
+		case NOTE_ON:
+		case NOTE_OFF:
+			printf("Channel %d, note %d, velocity %d\n", event.channel, event.note, event.velocity);
+			break;
+		case CONTROLER_ON:
+			printf("Channel %d, controller %d, value %d\n", event.channel, event.controller, event.value);
+			break;
+		default:
+			printf("Unknown event type %d\n", event.type);
+		}
+	}
+	return 0;
+}
diff --git a/share/examples/sound/ossmidi.h b/share/examples/sound/ossmidi.h
new file mode 100644
index 000000000000..507508061de4
--- /dev/null
+++ b/share/examples/sound/ossmidi.h
@@ -0,0 +1,63 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 Goran Mekić
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#define CMD_MASK 0xF0
+#define NOTE_ON 0x90
+#define NOTE_OFF 0x80
+#define CHANNEL_MASK 0xF
+#define CONTROLER_ON 0xB0
+
+typedef struct midi_event {
+	unsigned char type;
+	unsigned char channel;
+	union {
+		unsigned char note;
+		unsigned controller;
+	};
+	union {
+		unsigned char velocity;
+		unsigned char value;
+	};
+} midi_event_t;
+
+typedef struct midi_config {
+	char   *device;
+	int	fd;
+} midi_config_t;
+
+void
+oss_midi_init(midi_config_t *config)
+{
+	if ((config->fd = open(config->device, O_RDWR)) == -1) {
+		perror("Error opening MIDI device");
+		exit(1);
+	}
+}