ALSA: bebob: Add MIDI interface

This commit adds a functionality to capture/playback MIDI messages.

When no AMDTP streams are running, this module starts AMDTP stream at current
sampling rate for MIDI substream.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob_midi.c

@@ -0,0 +1,148 @@
+/*
+ * bebob_midi.c - a part of driver for BeBoB based devices
+ *
+ * Copyright (c) 2013-2014 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include "bebob.h"
+
+static int midi_capture_open(struct snd_rawmidi_substream *substream)
+{
+	struct snd_bebob *bebob = substream->rmidi->private_data;
+
+	atomic_inc(&bebob->capture_substreams);
+	return snd_bebob_stream_start_duplex(bebob, 0);
+}
+
+static int midi_playback_open(struct snd_rawmidi_substream *substream)
+{
+	struct snd_bebob *bebob = substream->rmidi->private_data;
+
+	atomic_inc(&bebob->playback_substreams);
+	return snd_bebob_stream_start_duplex(bebob, 0);
+}
+
+static int midi_capture_close(struct snd_rawmidi_substream *substream)
+{
+	struct snd_bebob *bebob = substream->rmidi->private_data;
+
+	atomic_dec(&bebob->capture_substreams);
+	snd_bebob_stream_stop_duplex(bebob);
+
+	return 0;
+}
+
+static int midi_playback_close(struct snd_rawmidi_substream *substream)
+{
+	struct snd_bebob *bebob = substream->rmidi->private_data;
+
+	atomic_dec(&bebob->playback_substreams);
+	snd_bebob_stream_stop_duplex(bebob);
+
+	return 0;
+}
+
+static void midi_capture_trigger(struct snd_rawmidi_substream *substrm, int up)
+{
+	struct snd_bebob *bebob = substrm->rmidi->private_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bebob->lock, flags);
+
+	if (up)
+		amdtp_stream_midi_trigger(&bebob->tx_stream,
+					  substrm->number, substrm);
+	else
+		amdtp_stream_midi_trigger(&bebob->tx_stream,
+					  substrm->number, NULL);
+
+	spin_unlock_irqrestore(&bebob->lock, flags);
+}
+
+static void midi_playback_trigger(struct snd_rawmidi_substream *substrm, int up)
+{
+	struct snd_bebob *bebob = substrm->rmidi->private_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bebob->lock, flags);
+
+	if (up)
+		amdtp_stream_midi_trigger(&bebob->rx_stream,
+					  substrm->number, substrm);
+	else
+		amdtp_stream_midi_trigger(&bebob->rx_stream,
+					  substrm->number, NULL);
+
+	spin_unlock_irqrestore(&bebob->lock, flags);
+}
+
+static struct snd_rawmidi_ops midi_capture_ops = {
+	.open		= midi_capture_open,
+	.close		= midi_capture_close,
+	.trigger	= midi_capture_trigger,
+};
+
+static struct snd_rawmidi_ops midi_playback_ops = {
+	.open		= midi_playback_open,
+	.close		= midi_playback_close,
+	.trigger	= midi_playback_trigger,
+};
+
+static void set_midi_substream_names(struct snd_bebob *bebob,
+				     struct snd_rawmidi_str *str)
+{
+	struct snd_rawmidi_substream *subs;
+
+	list_for_each_entry(subs, &str->substreams, list) {
+		snprintf(subs->name, sizeof(subs->name),
+			 "%s MIDI %d",
+			 bebob->card->shortname, subs->number + 1);
+	}
+}
+
+int snd_bebob_create_midi_devices(struct snd_bebob *bebob)
+{
+	struct snd_rawmidi *rmidi;
+	struct snd_rawmidi_str *str;
+	int err;
+
+	/* create midi ports */
+	err = snd_rawmidi_new(bebob->card, bebob->card->driver, 0,
+			      bebob->midi_output_ports, bebob->midi_input_ports,
+			      &rmidi);
+	if (err < 0)
+		return err;
+
+	snprintf(rmidi->name, sizeof(rmidi->name),
+		 "%s MIDI", bebob->card->shortname);
+	rmidi->private_data = bebob;
+
+	if (bebob->midi_input_ports > 0) {
+		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
+
+		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+					&midi_capture_ops);
+
+		str = &rmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT];
+
+		set_midi_substream_names(bebob, str);
+	}
+
+	if (bebob->midi_output_ports > 0) {
+		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
+
+		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+					&midi_playback_ops);
+
+		str = &rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT];
+
+		set_midi_substream_names(bebob, str);
+	}
+
+	if ((bebob->midi_output_ports > 0) && (bebob->midi_input_ports > 0))
+		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX;
+
+	return 0;
+}