1 files changed, 295 insertions, 0 deletions
diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c
new file mode 100644
index 000000000..0838632c7
--- /dev/null
+++ b/sound/usb/line6/midi.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/export.h>
+#include <sound/core.h>
+#include <sound/rawmidi.h>
+
+#include "driver.h"
+#include "midi.h"
+
+#define line6_rawmidi_substream_midi(substream) \
+	((struct snd_line6_midi *)((substream)->rmidi->private_data))
+
+static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
+			   int length);
+
+/*
+	Pass data received via USB to MIDI.
+*/
+void line6_midi_receive(struct usb_line6 *line6, unsigned char *data,
+			int length)
+{
+	if (line6->line6midi->substream_receive)
+		snd_rawmidi_receive(line6->line6midi->substream_receive,
+				    data, length);
+}
+
+/*
+	Read data from MIDI buffer and transmit them via USB.
+*/
+static void line6_midi_transmit(struct snd_rawmidi_substream *substream)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+	struct snd_line6_midi *line6midi = line6->line6midi;
+	struct midi_buffer *mb = &line6midi->midibuf_out;
+	unsigned char chunk[LINE6_FALLBACK_MAXPACKETSIZE];
+	int req, done;
+
+	for (;;) {
+		req = min3(line6_midibuf_bytes_free(mb), line6->max_packet_size,
+			   LINE6_FALLBACK_MAXPACKETSIZE);
+		done = snd_rawmidi_transmit_peek(substream, chunk, req);
+
+		if (done == 0)
+			break;
+
+		line6_midibuf_write(mb, chunk, done);
+		snd_rawmidi_transmit_ack(substream, done);
+	}
+
+	for (;;) {
+		done = line6_midibuf_read(mb, chunk,
+					  LINE6_FALLBACK_MAXPACKETSIZE,
+					  LINE6_MIDIBUF_READ_TX);
+
+		if (done == 0)
+			break;
+
+		send_midi_async(line6, chunk, done);
+	}
+}
+
+/*
+	Notification of completion of MIDI transmission.
+*/
+static void midi_sent(struct urb *urb)
+{
+	unsigned long flags;
+	int status;
+	int num;
+	struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
+
+	status = urb->status;
+	kfree(urb->transfer_buffer);
+	usb_free_urb(urb);
+
+	if (status == -ESHUTDOWN)
+		return;
+
+	spin_lock_irqsave(&line6->line6midi->lock, flags);
+	num = --line6->line6midi->num_active_send_urbs;
+
+	if (num == 0) {
+		line6_midi_transmit(line6->line6midi->substream_transmit);
+		num = line6->line6midi->num_active_send_urbs;
+	}
+
+	if (num == 0)
+		wake_up(&line6->line6midi->send_wait);
+
+	spin_unlock_irqrestore(&line6->line6midi->lock, flags);
+}
+
+/*
+	Send an asynchronous MIDI message.
+	Assumes that line6->line6midi->lock is held
+	(i.e., this function is serialized).
+*/
+static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
+			   int length)
+{
+	struct urb *urb;
+	int retval;
+	unsigned char *transfer_buffer;
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+
+	if (urb == NULL)
+		return -ENOMEM;
+
+	transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
+
+	if (transfer_buffer == NULL) {
+		usb_free_urb(urb);
+		return -ENOMEM;
+	}
+
+	usb_fill_int_urb(urb, line6->usbdev,
+			 usb_sndintpipe(line6->usbdev,
+					 line6->properties->ep_ctrl_w),
+			 transfer_buffer, length, midi_sent, line6,
+			 line6->interval);
+	urb->actual_length = 0;
+	retval = usb_urb_ep_type_check(urb);
+	if (retval < 0)
+		goto error;
+
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval < 0)
+		goto error;
+
+	++line6->line6midi->num_active_send_urbs;
+	return 0;
+
+ error:
+	dev_err(line6->ifcdev, "usb_submit_urb failed\n");
+	usb_free_urb(urb);
+	return retval;
+}
+
+static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream,
+				      int up)
+{
+	unsigned long flags;
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+
+	line6->line6midi->substream_transmit = substream;
+	spin_lock_irqsave(&line6->line6midi->lock, flags);
+
+	if (line6->line6midi->num_active_send_urbs == 0)
+		line6_midi_transmit(substream);
+
+	spin_unlock_irqrestore(&line6->line6midi->lock, flags);
+}
+
+static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+	struct snd_line6_midi *midi = line6->line6midi;
+
+	wait_event_interruptible(midi->send_wait,
+				 midi->num_active_send_urbs == 0);
+}
+
+static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static void line6_midi_input_trigger(struct snd_rawmidi_substream *substream,
+				     int up)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+
+	if (up)
+		line6->line6midi->substream_receive = substream;
+	else
+		line6->line6midi->substream_receive = NULL;
+}
+
+static const struct snd_rawmidi_ops line6_midi_output_ops = {
+	.open = line6_midi_output_open,
+	.close = line6_midi_output_close,
+	.trigger = line6_midi_output_trigger,
+	.drain = line6_midi_output_drain,
+};
+
+static const struct snd_rawmidi_ops line6_midi_input_ops = {
+	.open = line6_midi_input_open,
+	.close = line6_midi_input_close,
+	.trigger = line6_midi_input_trigger,
+};
+
+/* Create a MIDI device */
+static int snd_line6_new_midi(struct usb_line6 *line6,
+			      struct snd_rawmidi **rmidi_ret)
+{
+	struct snd_rawmidi *rmidi;
+	int err;
+
+	err = snd_rawmidi_new(line6->card, "Line 6 MIDI", 0, 1, 1, rmidi_ret);
+	if (err < 0)
+		return err;
+
+	rmidi = *rmidi_ret;
+	strcpy(rmidi->id, line6->properties->id);
+	strcpy(rmidi->name, line6->properties->name);
+
+	rmidi->info_flags =
+	    SNDRV_RAWMIDI_INFO_OUTPUT |
+	    SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
+
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+			    &line6_midi_output_ops);
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+			    &line6_midi_input_ops);
+	return 0;
+}
+
+/* MIDI device destructor */
+static void snd_line6_midi_free(struct snd_rawmidi *rmidi)
+{
+	struct snd_line6_midi *line6midi = rmidi->private_data;
+
+	line6_midibuf_destroy(&line6midi->midibuf_in);
+	line6_midibuf_destroy(&line6midi->midibuf_out);
+	kfree(line6midi);
+}
+
+/*
+	Initialize the Line 6 MIDI subsystem.
+*/
+int line6_init_midi(struct usb_line6 *line6)
+{
+	int err;
+	struct snd_rawmidi *rmidi;
+	struct snd_line6_midi *line6midi;
+
+	if (!(line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI)) {
+		/* skip MIDI initialization and report success */
+		return 0;
+	}
+
+	err = snd_line6_new_midi(line6, &rmidi);
+	if (err < 0)
+		return err;
+
+	line6midi = kzalloc(sizeof(struct snd_line6_midi), GFP_KERNEL);
+	if (!line6midi)
+		return -ENOMEM;
+
+	rmidi->private_data = line6midi;
+	rmidi->private_free = snd_line6_midi_free;
+
+	init_waitqueue_head(&line6midi->send_wait);
+	spin_lock_init(&line6midi->lock);
+	line6midi->line6 = line6;
+
+	err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
+	if (err < 0)
+		return err;
+
+	err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
+	if (err < 0)
+		return err;
+
+	line6->line6midi = line6midi;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(line6_init_midi);