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// SPDX-License-Identifier: GPL-2.0-or-later/* *   Generic MIDI synth driver for ALSA sequencer *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl> *                         Jaroslav Kysela <perex@perex.cz> */ /* Possible options for midisynth module:	- automatic opening of midi ports on first received event or subscription	  (close will be performed when client leaves)*/  #include <linux/init.h>#include <linux/slab.h>#include <linux/errno.h>#include <linux/string.h>#include <linux/module.h>#include <linux/mutex.h>#include <sound/core.h>#include <sound/rawmidi.h>#include <sound/seq_kernel.h>#include <sound/seq_device.h>#include <sound/seq_midi_event.h>#include <sound/initval.h>#include "seq_lock.h" MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");MODULE_LICENSE("GPL");static int output_buffer_size = PAGE_SIZE;module_param(output_buffer_size, int, 0644);MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");static int input_buffer_size = PAGE_SIZE;module_param(input_buffer_size, int, 0644);MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes."); /* data for this midi synth driver */struct seq_midisynth {	struct snd_card *card;	struct snd_rawmidi *rmidi;	int device;	int subdevice;	struct snd_rawmidi_substream __rcu *input_substream;	snd_use_lock_t input_use_lock;	/* in-flight event_input users */	struct snd_rawmidi_file input_rfile;	snd_use_lock_t output_use_lock;	/* in-flight event_input users */	struct snd_rawmidi_substream __rcu *output_substream;	struct snd_rawmidi_file output_rfile;	int seq_client;	int seq_port;	struct snd_midi_event *parser;}; struct seq_midisynth_client {	int seq_client;	int num_ports;	int ports_per_device[SNDRV_RAWMIDI_DEVICES]; 	struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];}; static struct seq_midisynth_client *synths[SNDRV_CARDS];static DEFINE_MUTEX(register_mutex); /* handle rawmidi input event (MIDI v1.0 stream) */static void snd_midi_input_event(struct snd_rawmidi_substream *substream){	struct snd_rawmidi_runtime *runtime;	struct seq_midisynth *msynth;	struct snd_seq_event ev;	char buf[16], *pbuf;	long res; 	if (substream == NULL)		return;	runtime = substream->runtime;	msynth = runtime->private_data;	if (msynth == NULL)		return; 	scoped_guard(rcu) {		if (rcu_dereference(msynth->input_substream) != substream)			return; 		snd_use_lock_use(&msynth->input_use_lock);	} 	memset(&ev, 0, sizeof(ev));	while (runtime->avail > 0) {		res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf));		if (res <= 0)			continue;		if (msynth->parser == NULL)			continue;		pbuf = buf;		while (res-- > 0) {			if (!snd_midi_event_encode_byte(msynth->parser,							*pbuf++, &ev))				continue;			ev.source.port = msynth->seq_port;			ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;			snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);			/* clear event and reset header */			memset(&ev, 0, sizeof(ev));		}	} 	snd_use_lock_free(&msynth->input_use_lock);} static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count){	struct snd_rawmidi_runtime *runtime;	int tmp; 	if (snd_BUG_ON(!substream || !buf))		return -EINVAL;	runtime = substream->runtime;	tmp = runtime->avail;	if (tmp < count) {		if (printk_ratelimit())			pr_err("ALSA: seq_midi: MIDI output buffer overrun\n");		return -ENOMEM;	}	if (snd_rawmidi_kernel_write(substream, buf, count) < count)		return -EINVAL;	return 0;} /* callback for snd_seq_dump_var_event(), bridging to dump_midi() */static int __dump_midi(void *ptr, void *buf, int count){	return dump_midi(ptr, buf, count);} static int event_process_midi(struct snd_seq_event *ev, int direct,			      void *private_data, int atomic, int hop){	struct seq_midisynth *msynth = private_data;	unsigned char msg[10];	/* buffer for constructing midi messages */	struct snd_rawmidi_substream *substream;	int err = 0;	int len; 	if (snd_BUG_ON(!msynth))		return -EINVAL; 	scoped_guard(rcu) {		substream = rcu_dereference(msynth->output_substream);		if (!substream)			return -ENODEV;		snd_use_lock_use(&msynth->output_use_lock);	} 	if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {	/* special case, to save space */		if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {			/* invalid event */			pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);			goto out;		}		snd_seq_dump_var_event(ev, __dump_midi, substream);		snd_midi_event_reset_decode(msynth->parser);	} else {		if (!msynth->parser) {			err = -EIO;			goto out;		}		len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);		if (len < 0)			goto out;		if (dump_midi(substream, msg, len) < 0)			snd_midi_event_reset_decode(msynth->parser);	} out:	snd_use_lock_free(&msynth->output_use_lock);	return err;}  static int snd_seq_midisynth_new(struct seq_midisynth *msynth,				 struct snd_card *card,				 int device,				 int subdevice){	if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)		return -ENOMEM;	msynth->card = card;	msynth->device = device;	msynth->subdevice = subdevice;	snd_use_lock_init(&msynth->input_use_lock);	snd_use_lock_init(&msynth->output_use_lock);	return 0;} /* open associated midi device for input */static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info){	int err;	struct seq_midisynth *msynth = private_data;	struct snd_rawmidi_runtime *runtime;	struct snd_rawmidi_file rfile = {};	struct snd_rawmidi_params params; 	/* open midi port */	err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,				      SNDRV_RAWMIDI_LFLG_INPUT,				      &rfile);	if (err < 0) {		pr_debug("ALSA: seq_midi: midi input open failed!!!\n");		return err;	}	runtime = rfile.input->runtime;	memset(&params, 0, sizeof(params));	params.avail_min = 1;	params.buffer_size = input_buffer_size;	err = snd_rawmidi_input_params(rfile.input, &params);	if (err < 0) {		snd_rawmidi_kernel_release(&rfile);		return err;	}	snd_midi_event_reset_encode(msynth->parser);	runtime->event = snd_midi_input_event;	runtime->private_data = msynth;	msynth->input_rfile = rfile;	rcu_assign_pointer(msynth->input_substream, rfile.input);	snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);	return 0;} /* close associated midi device for input */static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info){	int err;	struct seq_midisynth *msynth = private_data;	struct snd_rawmidi_file rfile; 	rcu_assign_pointer(msynth->input_substream, NULL);	synchronize_rcu();	snd_use_lock_sync(&msynth->input_use_lock); 	rfile = msynth->input_rfile;	msynth->input_rfile = (struct snd_rawmidi_file){}; 	if (snd_BUG_ON(!rfile.input))		return -EINVAL; 	err = snd_rawmidi_kernel_release(&rfile);	return err;} /* open associated midi device for output */static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info){	int err;	struct seq_midisynth *msynth = private_data;	struct snd_rawmidi_file rfile = {};	struct snd_rawmidi_params params; 	/* open midi port */	err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,				      SNDRV_RAWMIDI_LFLG_OUTPUT,				      &rfile);	if (err < 0) {		pr_debug("ALSA: seq_midi: midi output open failed!!!\n");		return err;	}	memset(&params, 0, sizeof(params));	params.avail_min = 1;	params.buffer_size = output_buffer_size;	params.no_active_sensing = 1;	err = snd_rawmidi_output_params(rfile.output, &params);	if (err < 0) {		snd_rawmidi_kernel_release(&rfile);		return err;	}	snd_midi_event_reset_decode(msynth->parser);	msynth->output_rfile = rfile;	rcu_assign_pointer(msynth->output_substream, rfile.output);	return 0;} /* close associated midi device for output */static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info){	struct seq_midisynth *msynth = private_data;	struct snd_rawmidi_file rfile; 	rcu_assign_pointer(msynth->output_substream, NULL);	synchronize_rcu();	snd_use_lock_sync(&msynth->output_use_lock);	rfile = msynth->output_rfile;	msynth->output_rfile = (struct snd_rawmidi_file){}; 	if (snd_BUG_ON(!rfile.output))		return -EINVAL;	snd_rawmidi_drain_output(rfile.output);	return snd_rawmidi_kernel_release(&rfile);} /* delete given midi synth port */static void snd_seq_midisynth_delete(struct seq_midisynth *msynth){	if (msynth == NULL)		return; 	if (msynth->seq_client > 0) {		/* delete port */		snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);	} 	snd_midi_event_free(msynth->parser);} /* register new midi synth port */static intsnd_seq_midisynth_probe(struct snd_seq_device *dev){	struct seq_midisynth_client *client;	struct seq_midisynth *msynth, *ms;	struct snd_rawmidi *rmidi = dev->private_data;	int newclient = 0;	unsigned int p, ports;	struct snd_seq_port_callback pcallbacks;	struct snd_card *card = dev->card;	int device = dev->device;	unsigned int input_count = 0, output_count = 0; 	if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))		return -EINVAL; 	struct snd_rawmidi_info *info __free(kfree) =		kmalloc_obj(*info);	if (! info)		return -ENOMEM;	info->device = device;	info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;	info->subdevice = 0;	if (snd_rawmidi_info_select(card, info) >= 0)		output_count = info->subdevices_count;	info->stream = SNDRV_RAWMIDI_STREAM_INPUT;	if (snd_rawmidi_info_select(card, info) >= 0) {		input_count = info->subdevices_count;	}	ports = output_count;	if (ports < input_count)		ports = input_count;	if (ports == 0)		return -ENODEV;	if (ports > (256 / SNDRV_RAWMIDI_DEVICES))		ports = 256 / SNDRV_RAWMIDI_DEVICES; 	guard(mutex)(&register_mutex);	client = synths[card->number];	if (client == NULL) {		newclient = 1;		client = kzalloc_obj(*client);		if (client == NULL)			return -ENOMEM;		client->seq_client =			snd_seq_create_kernel_client(				card, 0, "%s", card->shortname[0] ?				(const char *)card->shortname : "External MIDI");		if (client->seq_client < 0) {			kfree(client);			return -ENOMEM;		}	} 	msynth = kzalloc_objs(struct seq_midisynth, ports); 	struct snd_seq_port_info *port __free(kfree) =		kmalloc_obj(*port);	if (msynth == NULL || port == NULL)		goto __nomem; 	for (p = 0; p < ports; p++) {		ms = &msynth[p];		ms->rmidi = rmidi; 		if (snd_seq_midisynth_new(ms, card, device, p) < 0)			goto __nomem; 		/* declare port */		memset(port, 0, sizeof(*port));		port->addr.client = client->seq_client;		port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;		port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;		memset(info, 0, sizeof(*info));		info->device = device;		if (p < output_count)			info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;		else			info->stream = SNDRV_RAWMIDI_STREAM_INPUT;		info->subdevice = p;		if (snd_rawmidi_info_select(card, info) >= 0)			strscpy(port->name, info->subname);		if (! port->name[0]) {			if (info->name[0]) {				if (ports > 1)					scnprintf(port->name, sizeof(port->name), "%s-%u", info->name, p);				else					scnprintf(port->name, sizeof(port->name), "%s", info->name);			} else {				/* last resort */				if (ports > 1)					sprintf(port->name, "MIDI %d-%d-%u", card->number, device, p);				else					sprintf(port->name, "MIDI %d-%d", card->number, device);			}		}		if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)			port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;		if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)			port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;		if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&		    info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)			port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;		if (port->capability & SNDRV_SEQ_PORT_CAP_READ)			port->direction |= SNDRV_SEQ_PORT_DIR_INPUT;		if (port->capability & SNDRV_SEQ_PORT_CAP_WRITE)			port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT;		port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC			| SNDRV_SEQ_PORT_TYPE_HARDWARE			| SNDRV_SEQ_PORT_TYPE_PORT;		port->midi_channels = 16;		memset(&pcallbacks, 0, sizeof(pcallbacks));		pcallbacks.owner = THIS_MODULE;		pcallbacks.private_data = ms;		pcallbacks.subscribe = midisynth_subscribe;		pcallbacks.unsubscribe = midisynth_unsubscribe;		pcallbacks.use = midisynth_use;		pcallbacks.unuse = midisynth_unuse;		pcallbacks.event_input = event_process_midi;		port->kernel = &pcallbacks;		if (rmidi->ops && rmidi->ops->get_port_info)			rmidi->ops->get_port_info(rmidi, p, port);		if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)			goto __nomem;		ms->seq_client = client->seq_client;		ms->seq_port = port->addr.port;	}	client->ports_per_device[device] = ports;	client->ports[device] = msynth;	client->num_ports++;	if (newclient)		synths[card->number] = client;	return 0;	/* success */       __nomem:	if (msynth != NULL) {	      	for (p = 0; p < ports; p++)	      		snd_seq_midisynth_delete(&msynth[p]);		kfree(msynth);	}	if (newclient) {		snd_seq_delete_kernel_client(client->seq_client);		kfree(client);	}	return -ENOMEM;} /* release midi synth port */static voidsnd_seq_midisynth_remove(struct snd_seq_device *dev){	struct seq_midisynth_client *client;	struct seq_midisynth *msynth;	struct snd_card *card = dev->card;	int device = dev->device, p, ports;		guard(mutex)(&register_mutex);	client = synths[card->number];	if (client == NULL || client->ports[device] == NULL)		return;	ports = client->ports_per_device[device];	client->ports_per_device[device] = 0;	msynth = client->ports[device];	client->ports[device] = NULL;	for (p = 0; p < ports; p++)		snd_seq_midisynth_delete(&msynth[p]);	kfree(msynth);	client->num_ports--;	if (client->num_ports <= 0) {		snd_seq_delete_kernel_client(client->seq_client);		synths[card->number] = NULL;		kfree(client);	}} static struct snd_seq_driver seq_midisynth_driver = {	.probe = snd_seq_midisynth_probe,	.remove = snd_seq_midisynth_remove,	.driver = {		.name = KBUILD_MODNAME,	},	.id = SNDRV_SEQ_DEV_ID_MIDISYNTH,	.argsize = 0,};

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