1 files changed, 527 insertions, 0 deletions

diff --git a/sound/core/seq/seq_virmidi.c b/sound/core/seq/seq_virmidi.c
new file mode 100644
index 000000000..f5cae4950
--- /dev/null
+++ b/sound/core/seq/seq_virmidi.c
@@ -0,0 +1,527 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Virtual Raw MIDI client on Sequencer
+ *
+ *  Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,
+ *                        Jaroslav Kysela <perex@perex.cz>
+ */
+
+/*
+ * Virtual Raw MIDI client
+ *
+ * The virtual rawmidi client is a sequencer client which associate
+ * a rawmidi device file.  The created rawmidi device file can be
+ * accessed as a normal raw midi, but its MIDI source and destination
+ * are arbitrary.  For example, a user-client software synth connected
+ * to this port can be used as a normal midi device as well.
+ *
+ * The virtual rawmidi device accepts also multiple opens.  Each file
+ * has its own input buffer, so that no conflict would occur.  The drain
+ * of input/output buffer acts only to the local buffer.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/rawmidi.h>
+#include <sound/info.h>
+#include <sound/control.h>
+#include <sound/minors.h>
+#include <sound/seq_kernel.h>
+#include <sound/seq_midi_event.h>
+#include <sound/seq_virmidi.h>
+
+MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
+MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer");
+MODULE_LICENSE("GPL");
+
+/*
+ * initialize an event record
+ */
+static void snd_virmidi_init_event(struct snd_virmidi *vmidi,
+				   struct snd_seq_event *ev)
+{
+	memset(ev, 0, sizeof(*ev));
+	ev->source.port = vmidi->port;
+	switch (vmidi->seq_mode) {
+	case SNDRV_VIRMIDI_SEQ_DISPATCH:
+		ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
+		break;
+	case SNDRV_VIRMIDI_SEQ_ATTACH:
+		/* FIXME: source and destination are same - not good.. */
+		ev->dest.client = vmidi->client;
+		ev->dest.port = vmidi->port;
+		break;
+	}
+	ev->type = SNDRV_SEQ_EVENT_NONE;
+}
+
+/*
+ * decode input event and put to read buffer of each opened file
+ */
+static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,
+					 struct snd_seq_event *ev,
+					 bool atomic)
+{
+	struct snd_virmidi *vmidi;
+	unsigned char msg[4];
+	int len;
+
+	if (atomic)
+		read_lock(&rdev->filelist_lock);
+	else
+		down_read(&rdev->filelist_sem);
+	list_for_each_entry(vmidi, &rdev->filelist, list) {
+		if (!READ_ONCE(vmidi->trigger))
+			continue;
+		if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
+			if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
+				continue;
+			snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream);
+			snd_midi_event_reset_decode(vmidi->parser);
+		} else {
+			len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev);
+			if (len > 0)
+				snd_rawmidi_receive(vmidi->substream, msg, len);
+		}
+	}
+	if (atomic)
+		read_unlock(&rdev->filelist_lock);
+	else
+		up_read(&rdev->filelist_sem);
+
+	return 0;
+}
+
+/*
+ * event handler of virmidi port
+ */
+static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,
+				   void *private_data, int atomic, int hop)
+{
+	struct snd_virmidi_dev *rdev;
+
+	rdev = private_data;
+	if (!(rdev->flags & SNDRV_VIRMIDI_USE))
+		return 0; /* ignored */
+	return snd_virmidi_dev_receive_event(rdev, ev, atomic);
+}
+
+/*
+ * trigger rawmidi stream for input
+ */
+static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct snd_virmidi *vmidi = substream->runtime->private_data;
+
+	WRITE_ONCE(vmidi->trigger, !!up);
+}
+
+/* process rawmidi bytes and send events;
+ * we need no lock here for vmidi->event since it's handled only in this work
+ */
+static void snd_vmidi_output_work(struct work_struct *work)
+{
+	struct snd_virmidi *vmidi;
+	struct snd_rawmidi_substream *substream;
+	unsigned char input;
+	int ret;
+
+	vmidi = container_of(work, struct snd_virmidi, output_work);
+	substream = vmidi->substream;
+
+	/* discard the outputs in dispatch mode unless subscribed */
+	if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&
+	    !(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {
+		snd_rawmidi_proceed(substream);
+		return;
+	}
+
+	while (READ_ONCE(vmidi->trigger)) {
+		if (snd_rawmidi_transmit(substream, &input, 1) != 1)
+			break;
+		if (!snd_midi_event_encode_byte(vmidi->parser, input,
+						&vmidi->event))
+			continue;
+		if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
+			ret = snd_seq_kernel_client_dispatch(vmidi->client,
+							     &vmidi->event,
+							     false, 0);
+			vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
+			if (ret < 0)
+				break;
+		}
+		/* rawmidi input might be huge, allow to have a break */
+		cond_resched();
+	}
+}
+
+/*
+ * trigger rawmidi stream for output
+ */
+static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct snd_virmidi *vmidi = substream->runtime->private_data;
+
+	WRITE_ONCE(vmidi->trigger, !!up);
+	if (up)
+		queue_work(system_highpri_wq, &vmidi->output_work);
+}
+
+/*
+ * open rawmidi handle for input
+ */
+static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
+{
+	struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
+	struct snd_rawmidi_runtime *runtime = substream->runtime;
+	struct snd_virmidi *vmidi;
+
+	vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
+	if (vmidi == NULL)
+		return -ENOMEM;
+	vmidi->substream = substream;
+	if (snd_midi_event_new(0, &vmidi->parser) < 0) {
+		kfree(vmidi);
+		return -ENOMEM;
+	}
+	vmidi->seq_mode = rdev->seq_mode;
+	vmidi->client = rdev->client;
+	vmidi->port = rdev->port;	
+	runtime->private_data = vmidi;
+	down_write(&rdev->filelist_sem);
+	write_lock_irq(&rdev->filelist_lock);
+	list_add_tail(&vmidi->list, &rdev->filelist);
+	write_unlock_irq(&rdev->filelist_lock);
+	up_write(&rdev->filelist_sem);
+	vmidi->rdev = rdev;
+	return 0;
+}
+
+/*
+ * open rawmidi handle for output
+ */
+static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)
+{
+	struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
+	struct snd_rawmidi_runtime *runtime = substream->runtime;
+	struct snd_virmidi *vmidi;
+
+	vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
+	if (vmidi == NULL)
+		return -ENOMEM;
+	vmidi->substream = substream;
+	if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) {
+		kfree(vmidi);
+		return -ENOMEM;
+	}
+	vmidi->seq_mode = rdev->seq_mode;
+	vmidi->client = rdev->client;
+	vmidi->port = rdev->port;
+	snd_virmidi_init_event(vmidi, &vmidi->event);
+	vmidi->rdev = rdev;
+	INIT_WORK(&vmidi->output_work, snd_vmidi_output_work);
+	runtime->private_data = vmidi;
+	return 0;
+}
+
+/*
+ * close rawmidi handle for input
+ */
+static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
+{
+	struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
+	struct snd_virmidi *vmidi = substream->runtime->private_data;
+
+	down_write(&rdev->filelist_sem);
+	write_lock_irq(&rdev->filelist_lock);
+	list_del(&vmidi->list);
+	write_unlock_irq(&rdev->filelist_lock);
+	up_write(&rdev->filelist_sem);
+	snd_midi_event_free(vmidi->parser);
+	substream->runtime->private_data = NULL;
+	kfree(vmidi);
+	return 0;
+}
+
+/*
+ * close rawmidi handle for output
+ */
+static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)
+{
+	struct snd_virmidi *vmidi = substream->runtime->private_data;
+
+	WRITE_ONCE(vmidi->trigger, false); /* to be sure */
+	cancel_work_sync(&vmidi->output_work);
+	snd_midi_event_free(vmidi->parser);
+	substream->runtime->private_data = NULL;
+	kfree(vmidi);
+	return 0;
+}
+
+/*
+ * drain output work queue
+ */
+static void snd_virmidi_output_drain(struct snd_rawmidi_substream *substream)
+{
+	struct snd_virmidi *vmidi = substream->runtime->private_data;
+
+	flush_work(&vmidi->output_work);
+}
+
+/*
+ * subscribe callback - allow output to rawmidi device
+ */
+static int snd_virmidi_subscribe(void *private_data,
+				 struct snd_seq_port_subscribe *info)
+{
+	struct snd_virmidi_dev *rdev;
+
+	rdev = private_data;
+	if (!try_module_get(rdev->card->module))
+		return -EFAULT;
+	rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE;
+	return 0;
+}
+
+/*
+ * unsubscribe callback - disallow output to rawmidi device
+ */
+static int snd_virmidi_unsubscribe(void *private_data,
+				   struct snd_seq_port_subscribe *info)
+{
+	struct snd_virmidi_dev *rdev;
+
+	rdev = private_data;
+	rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE;
+	module_put(rdev->card->module);
+	return 0;
+}
+
+
+/*
+ * use callback - allow input to rawmidi device
+ */
+static int snd_virmidi_use(void *private_data,
+			   struct snd_seq_port_subscribe *info)
+{
+	struct snd_virmidi_dev *rdev;
+
+	rdev = private_data;
+	if (!try_module_get(rdev->card->module))
+		return -EFAULT;
+	rdev->flags |= SNDRV_VIRMIDI_USE;
+	return 0;
+}
+
+/*
+ * unuse callback - disallow input to rawmidi device
+ */
+static int snd_virmidi_unuse(void *private_data,
+			     struct snd_seq_port_subscribe *info)
+{
+	struct snd_virmidi_dev *rdev;
+
+	rdev = private_data;
+	rdev->flags &= ~SNDRV_VIRMIDI_USE;
+	module_put(rdev->card->module);
+	return 0;
+}
+
+
+/*
+ *  Register functions
+ */
+
+static const struct snd_rawmidi_ops snd_virmidi_input_ops = {
+	.open = snd_virmidi_input_open,
+	.close = snd_virmidi_input_close,
+	.trigger = snd_virmidi_input_trigger,
+};
+
+static const struct snd_rawmidi_ops snd_virmidi_output_ops = {
+	.open = snd_virmidi_output_open,
+	.close = snd_virmidi_output_close,
+	.trigger = snd_virmidi_output_trigger,
+	.drain = snd_virmidi_output_drain,
+};
+
+/*
+ * create a sequencer client and a port
+ */
+static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)
+{
+	int client;
+	struct snd_seq_port_callback pcallbacks;
+	struct snd_seq_port_info *pinfo;
+	int err;
+
+	if (rdev->client >= 0)
+		return 0;
+
+	pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL);
+	if (!pinfo) {
+		err = -ENOMEM;
+		goto __error;
+	}
+
+	client = snd_seq_create_kernel_client(rdev->card, rdev->device,
+					      "%s %d-%d", rdev->rmidi->name,
+					      rdev->card->number,
+					      rdev->device);
+	if (client < 0) {
+		err = client;
+		goto __error;
+	}
+	rdev->client = client;
+
+	/* create a port */
+	pinfo->addr.client = client;
+	sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device);
+	/* set all capabilities */
+	pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
+	pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
+	pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
+	pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
+		| SNDRV_SEQ_PORT_TYPE_SOFTWARE
+		| SNDRV_SEQ_PORT_TYPE_PORT;
+	pinfo->midi_channels = 16;
+	memset(&pcallbacks, 0, sizeof(pcallbacks));
+	pcallbacks.owner = THIS_MODULE;
+	pcallbacks.private_data = rdev;
+	pcallbacks.subscribe = snd_virmidi_subscribe;
+	pcallbacks.unsubscribe = snd_virmidi_unsubscribe;
+	pcallbacks.use = snd_virmidi_use;
+	pcallbacks.unuse = snd_virmidi_unuse;
+	pcallbacks.event_input = snd_virmidi_event_input;
+	pinfo->kernel = &pcallbacks;
+	err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo);
+	if (err < 0) {
+		snd_seq_delete_kernel_client(client);
+		rdev->client = -1;
+		goto __error;
+	}
+
+	rdev->port = pinfo->addr.port;
+	err = 0; /* success */
+
+ __error:
+	kfree(pinfo);
+	return err;
+}
+
+
+/*
+ * release the sequencer client
+ */
+static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)
+{
+	if (rdev->client >= 0) {
+		snd_seq_delete_kernel_client(rdev->client);
+		rdev->client = -1;
+	}
+}
+
+/*
+ * register the device
+ */
+static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)
+{
+	struct snd_virmidi_dev *rdev = rmidi->private_data;
+	int err;
+
+	switch (rdev->seq_mode) {
+	case SNDRV_VIRMIDI_SEQ_DISPATCH:
+		err = snd_virmidi_dev_attach_seq(rdev);
+		if (err < 0)
+			return err;
+		break;
+	case SNDRV_VIRMIDI_SEQ_ATTACH:
+		if (rdev->client == 0)
+			return -EINVAL;
+		/* should check presence of port more strictly.. */
+		break;
+	default:
+		pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+
+/*
+ * unregister the device
+ */
+static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
+{
+	struct snd_virmidi_dev *rdev = rmidi->private_data;
+
+	if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)
+		snd_virmidi_dev_detach_seq(rdev);
+	return 0;
+}
+
+/*
+ *
+ */
+static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
+	.dev_register = snd_virmidi_dev_register,
+	.dev_unregister = snd_virmidi_dev_unregister,
+};
+
+/*
+ * free device
+ */
+static void snd_virmidi_free(struct snd_rawmidi *rmidi)
+{
+	struct snd_virmidi_dev *rdev = rmidi->private_data;
+	kfree(rdev);
+}
+
+/*
+ * create a new device
+ *
+ */
+/* exported */
+int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)
+{
+	struct snd_rawmidi *rmidi;
+	struct snd_virmidi_dev *rdev;
+	int err;
+	
+	*rrmidi = NULL;
+	err = snd_rawmidi_new(card, "VirMidi", device,
+			      16,	/* may be configurable */
+			      16,	/* may be configurable */
+			      &rmidi);
+	if (err < 0)
+		return err;
+	strcpy(rmidi->name, rmidi->id);
+	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+	if (rdev == NULL) {
+		snd_device_free(card, rmidi);
+		return -ENOMEM;
+	}
+	rdev->card = card;
+	rdev->rmidi = rmidi;
+	rdev->device = device;
+	rdev->client = -1;
+	init_rwsem(&rdev->filelist_sem);
+	rwlock_init(&rdev->filelist_lock);
+	INIT_LIST_HEAD(&rdev->filelist);
+	rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
+	rmidi->private_data = rdev;
+	rmidi->private_free = snd_virmidi_free;
+	rmidi->ops = &snd_virmidi_global_ops;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops);
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops);
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT |
+			    SNDRV_RAWMIDI_INFO_OUTPUT |
+			    SNDRV_RAWMIDI_INFO_DUPLEX;
+	*rrmidi = rmidi;
+	return 0;
+}
+EXPORT_SYMBOL(snd_virmidi_new);