sound/core/seq/oss/seq_oss_midi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OSS compatible sequencer driver
 *
 * MIDI device handlers
 *
 * Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>
 */

#include <sound/asoundef.h>
#include "seq_oss_midi.h"
#include "seq_oss_readq.h"
#include "seq_oss_timer.h"
#include "seq_oss_event.h"
#include <sound/seq_midi_event.h>
#include "../seq_lock.h"
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/nospec.h>


/*
 * constants
 */
#define SNDRV_SEQ_OSS_MAX_MIDI_NAME	30

/*
 * definition of midi device record
 */
struct seq_oss_midi {
	int seq_device;		/* device number */
	int client;		/* sequencer client number */
	int port;		/* sequencer port number */
	unsigned int flags;	/* port capability */
	int opened;		/* flag for opening */
	unsigned char name[SNDRV_SEQ_OSS_MAX_MIDI_NAME];
	struct snd_midi_event *coder;	/* MIDI event coder */
	struct seq_oss_devinfo *devinfo;	/* assigned OSSseq device */
	snd_use_lock_t use_lock;
};


/*
 * midi device table
 */
static int max_midi_devs;
static struct seq_oss_midi *midi_devs[SNDRV_SEQ_OSS_MAX_MIDI_DEVS];

static DEFINE_SPINLOCK(register_lock);

/*
 * prototypes
 */
static struct seq_oss_midi *get_mdev(int dev);
static struct seq_oss_midi *get_mididev(struct seq_oss_devinfo *dp, int dev);
static int send_synth_event(struct seq_oss_devinfo *dp, struct snd_seq_event *ev, int dev);
static int send_midi_event(struct seq_oss_devinfo *dp, struct snd_seq_event *ev, struct seq_oss_midi *mdev);

/*
 * look up the existing ports
 * this looks a very exhausting job.
 */
int
snd_seq_oss_midi_lookup_ports(int client)
{
	struct snd_seq_client_info *clinfo;
	struct snd_seq_port_info *pinfo;

	clinfo = kzalloc(sizeof(*clinfo), GFP_KERNEL);
	pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL);
	if (! clinfo || ! pinfo) {
		kfree(clinfo);
		kfree(pinfo);
		return -ENOMEM;
	}
	clinfo->client = -1;
	while (snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT, clinfo) == 0) {
		if (clinfo->client == client)
			continue; /* ignore myself */
		pinfo->addr.client = clinfo->client;
		pinfo->addr.port = -1;
		while (snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_QUERY_NEXT_PORT, pinfo) == 0)
			snd_seq_oss_midi_check_new_port(pinfo);
	}
	kfree(clinfo);
	kfree(pinfo);
	return 0;
}


/*
 */
static struct seq_oss_midi *
get_mdev(int dev)
{
	struct seq_oss_midi *mdev;
	unsigned long flags;

	spin_lock_irqsave(&register_lock, flags);
	mdev = midi_devs[dev];
	if (mdev)
		snd_use_lock_use(&mdev->use_lock);
	spin_unlock_irqrestore(&register_lock, flags);
	return mdev;
}

/*
 * look for the identical slot
 */
static struct seq_oss_midi *
find_slot(int client, int port)
{
	int i;
	struct seq_oss_midi *mdev;
	unsigned long flags;

	spin_lock_irqsave(&register_lock, flags);
	for (i = 0; i < max_midi_devs; i++) {
		mdev = midi_devs[i];
		if (mdev && mdev->client == client && mdev->port == port) {
			/* found! */
			snd_use_lock_use(&mdev->use_lock);
			spin_unlock_irqrestore(&register_lock, flags);
			return mdev;
		}
	}
	spin_unlock_irqrestore(&register_lock, flags);
	return NULL;
}


#define PERM_WRITE (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_SUBS_WRITE)
#define PERM_READ (SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ)
/*
 * register a new port if it doesn't exist yet
 */
int
snd_seq_oss_midi_check_new_port(struct snd_seq_port_info *pinfo)
{
	int i;
	struct seq_oss_midi *mdev;
	unsigned long flags;

	/* the port must include generic midi */
	if (! (pinfo->type & SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC))
		return 0;
	/* either read or write subscribable */
	if ((pinfo->capability & PERM_WRITE) != PERM_WRITE &&
	    (pinfo->capability & PERM_READ) != PERM_READ)
		return 0;

	/*
	 * look for the identical slot
	 */
	if ((mdev = find_slot(pinfo->addr.client, pinfo->addr.port)) != NULL) {
		/* already exists */
		snd_use_lock_free(&mdev->use_lock);
		return 0;
	}

	/*
	 * allocate midi info record
	 */
	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
	if (!mdev)
		return -ENOMEM;

	/* copy the port information */
	mdev->client = pinfo->addr.client;
	mdev->port = pinfo->addr.port;
	mdev->flags = pinfo->capability;
	mdev->opened = 0;
	snd_use_lock_init(&mdev->use_lock);

	/* copy and truncate the name of synth device */
	strlcpy(mdev->name, pinfo->name, sizeof(mdev->name));

	/* create MIDI coder */
	if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &mdev->coder) < 0) {
		pr_err("ALSA: seq_oss: can't malloc midi coder\n");
		kfree(mdev);
		return -ENOMEM;
	}
	/* OSS sequencer adds running status to all sequences */
	snd_midi_event_no_status(mdev->coder, 1);

	/*
	 * look for en empty slot
	 */
	spin_lock_irqsave(&register_lock, flags);
	for (i = 0; i < max_midi_devs; i++) {
		if (midi_devs[i] == NULL)
			break;
	}
	if (i >= max_midi_devs) {
		if (max_midi_devs >= SNDRV_SEQ_OSS_MAX_MIDI_DEVS) {
			spin_unlock_irqrestore(&register_lock, flags);
			snd_midi_event_free(mdev->coder);
			kfree(mdev);
			return -ENOMEM;
		}
		max_midi_devs++;
	}
	mdev->seq_device = i;
	midi_devs[mdev->seq_device] = mdev;
	spin_unlock_irqrestore(&register_lock, flags);

	return 0;
}

/*
 * release the midi device if it was registered
 */
int
snd_seq_oss_midi_check_exit_port(int client, int port)
{
	struct seq_oss_midi *mdev;
	unsigned long flags;
	int index;

	if ((mdev = find_slot(client, port)) != NULL) {
		spin_lock_irqsave(&register_lock, flags);
		midi_devs[mdev->seq_device] = NULL;
		spin_unlock_irqrestore(&register_lock, flags);
		snd_use_lock_free(&mdev->use_lock);
		snd_use_lock_sync(&mdev->use_lock);
		snd_midi_event_free(mdev->coder);
		kfree(mdev);
	}
	spin_lock_irqsave(&register_lock, flags);
	for (index = max_midi_devs - 1; index >= 0; index--) {
		if (midi_devs[index])
			break;
	}
	max_midi_devs = index + 1;
	spin_unlock_irqrestore(&register_lock, flags);
	return 0;
}


/*
 * release the midi device if it was registered
 */
void
snd_seq_oss_midi_clear_all(void)
{
	int i;
	struct seq_oss_midi *mdev;
	unsigned long flags;

	spin_lock_irqsave(&register_lock, flags);
	for (i = 0; i < max_midi_devs; i++) {
		if ((mdev = midi_devs[i]) != NULL) {
			snd_midi_event_free(mdev->coder);
			kfree(mdev);
			midi_devs[i] = NULL;
		}
	}
	max_midi_devs = 0;
	spin_unlock_irqrestore(&register_lock, flags);
}


/*
 * set up midi tables
 */
void
snd_seq_oss_midi_setup(struct seq_oss_devinfo *dp)
{
	dp->max_mididev = max_midi_devs;
}

/*
 * clean up midi tables
 */
void
snd_seq_oss_midi_cleanup(struct seq_oss_devinfo *dp)
{
	int i;
	for (i = 0; i < dp->max_mididev; i++)
		snd_seq_oss_midi_close(dp, i);
	dp->max_mididev = 0;
}


/*
 * open all midi devices.  ignore errors.
 */
void
snd_seq_oss_midi_open_all(struct seq_oss_devinfo *dp, int file_mode)
{
	int i;
	for (i = 0; i < dp->max_mididev; i++)
		snd_seq_oss_midi_open(dp, i, file_mode);
}


/*
 * get the midi device information
 */
static struct seq_oss_midi *
get_mididev(struct seq_oss_devinfo *dp, int dev)
{
	if (dev < 0 || dev >= dp->max_mididev)
		return NULL;
	dev = array_index_nospec(dev, dp->max_mididev);
	return get_mdev(dev);
}


/*
 * open the midi device if not opened yet
 */
int
snd_seq_oss_midi_open(struct seq_oss_devinfo *dp, int dev, int fmode)
{
	int perm;
	struct seq_oss_midi *mdev;
	struct snd_seq_port_subscribe subs;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return -ENODEV;

	/* already used? */
	if (mdev->opened && mdev->devinfo != dp) {
		snd_use_lock_free(&mdev->use_lock);
		return -EBUSY;
	}

	perm = 0;
	if (is_write_mode(fmode))
		perm |= PERM_WRITE;
	if (is_read_mode(fmode))
		perm |= PERM_READ;
	perm &= mdev->flags;
	if (perm == 0) {
		snd_use_lock_free(&mdev->use_lock);
		return -ENXIO;
	}

	/* already opened? */
	if ((mdev->opened & perm) == perm) {
		snd_use_lock_free(&mdev->use_lock);
		return 0;
	}

	perm &= ~mdev->opened;

	memset(&subs, 0, sizeof(subs));

	if (perm & PERM_WRITE) {
		subs.sender = dp->addr;
		subs.dest.client = mdev->client;
		subs.dest.port = mdev->port;
		if (snd_seq_kernel_client_ctl(dp->cseq, SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT, &subs) >= 0)
			mdev->opened |= PERM_WRITE;
	}
	if (perm & PERM_READ) {
		subs.sender.client = mdev->client;
		subs.sender.port = mdev->port;
		subs.dest = dp->addr;
		subs.flags = SNDRV_SEQ_PORT_SUBS_TIMESTAMP;
		subs.queue = dp->queue;		/* queue for timestamps */
		if (snd_seq_kernel_client_ctl(dp->cseq, SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT, &subs) >= 0)
			mdev->opened |= PERM_READ;
	}

	if (! mdev->opened) {
		snd_use_lock_free(&mdev->use_lock);
		return -ENXIO;
	}

	mdev->devinfo = dp;
	snd_use_lock_free(&mdev->use_lock);
	return 0;
}

/*
 * close the midi device if already opened
 */
int
snd_seq_oss_midi_close(struct seq_oss_devinfo *dp, int dev)
{
	struct seq_oss_midi *mdev;
	struct snd_seq_port_subscribe subs;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return -ENODEV;
	if (! mdev->opened || mdev->devinfo != dp) {
		snd_use_lock_free(&mdev->use_lock);
		return 0;
	}

	memset(&subs, 0, sizeof(subs));
	if (mdev->opened & PERM_WRITE) {
		subs.sender = dp->addr;
		subs.dest.client = mdev->client;
		subs.dest.port = mdev->port;
		snd_seq_kernel_client_ctl(dp->cseq, SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT, &subs);
	}
	if (mdev->opened & PERM_READ) {
		subs.sender.client = mdev->client;
		subs.sender.port = mdev->port;
		subs.dest = dp->addr;
		snd_seq_kernel_client_ctl(dp->cseq, SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT, &subs);
	}

	mdev->opened = 0;
	mdev->devinfo = NULL;

	snd_use_lock_free(&mdev->use_lock);
	return 0;
}

/*
 * change seq capability flags to file mode flags
 */
int
snd_seq_oss_midi_filemode(struct seq_oss_devinfo *dp, int dev)
{
	struct seq_oss_midi *mdev;
	int mode;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return 0;

	mode = 0;
	if (mdev->opened & PERM_WRITE)
		mode |= SNDRV_SEQ_OSS_FILE_WRITE;
	if (mdev->opened & PERM_READ)
		mode |= SNDRV_SEQ_OSS_FILE_READ;

	snd_use_lock_free(&mdev->use_lock);
	return mode;
}

/*
 * reset the midi device and close it:
 * so far, only close the device.
 */
void
snd_seq_oss_midi_reset(struct seq_oss_devinfo *dp, int dev)
{
	struct seq_oss_midi *mdev;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return;
	if (! mdev->opened) {
		snd_use_lock_free(&mdev->use_lock);
		return;
	}

	if (mdev->opened & PERM_WRITE) {
		struct snd_seq_event ev;
		int c;

		memset(&ev, 0, sizeof(ev));
		ev.dest.client = mdev->client;
		ev.dest.port = mdev->port;
		ev.queue = dp->queue;
		ev.source.port = dp->port;
		if (dp->seq_mode == SNDRV_SEQ_OSS_MODE_SYNTH) {
			ev.type = SNDRV_SEQ_EVENT_SENSING;
			snd_seq_oss_dispatch(dp, &ev, 0, 0);
		}
		for (c = 0; c < 16; c++) {
			ev.type = SNDRV_SEQ_EVENT_CONTROLLER;
			ev.data.control.channel = c;
			ev.data.control.param = MIDI_CTL_ALL_NOTES_OFF;
			snd_seq_oss_dispatch(dp, &ev, 0, 0);
			if (dp->seq_mode == SNDRV_SEQ_OSS_MODE_MUSIC) {
				ev.data.control.param =
					MIDI_CTL_RESET_CONTROLLERS;
				snd_seq_oss_dispatch(dp, &ev, 0, 0);
				ev.type = SNDRV_SEQ_EVENT_PITCHBEND;
				ev.data.control.value = 0;
				snd_seq_oss_dispatch(dp, &ev, 0, 0);
			}
		}
	}
	// snd_seq_oss_midi_close(dp, dev);
	snd_use_lock_free(&mdev->use_lock);
}


/*
 * get client/port of the specified MIDI device
 */
void
snd_seq_oss_midi_get_addr(struct seq_oss_devinfo *dp, int dev, struct snd_seq_addr *addr)
{
	struct seq_oss_midi *mdev;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return;
	addr->client = mdev->client;
	addr->port = mdev->port;
	snd_use_lock_free(&mdev->use_lock);
}


/*
 * input callback - this can be atomic
 */
int
snd_seq_oss_midi_input(struct snd_seq_event *ev, int direct, void *private_data)
{
	struct seq_oss_devinfo *dp = (struct seq_oss_devinfo *)private_data;
	struct seq_oss_midi *mdev;
	int rc;

	if (dp->readq == NULL)
		return 0;
	if ((mdev = find_slot(ev->source.client, ev->source.port)) == NULL)
		return 0;
	if (! (mdev->opened & PERM_READ)) {
		snd_use_lock_free(&mdev->use_lock);
		return 0;
	}

	if (dp->seq_mode == SNDRV_SEQ_OSS_MODE_MUSIC)
		rc = send_synth_event(dp, ev, mdev->seq_device);
	else
		rc = send_midi_event(dp, ev, mdev);

	snd_use_lock_free(&mdev->use_lock);
	return rc;
}

/*
 * convert ALSA sequencer event to OSS synth event
 */
static int
send_synth_event(struct seq_oss_devinfo *dp, struct snd_seq_event *ev, int dev)
{
	union evrec ossev;

	memset(&ossev, 0, sizeof(ossev));

	switch (ev->type) {
	case SNDRV_SEQ_EVENT_NOTEON:
		ossev.v.cmd = MIDI_NOTEON; break;
	case SNDRV_SEQ_EVENT_NOTEOFF:
		ossev.v.cmd = MIDI_NOTEOFF; break;
	case SNDRV_SEQ_EVENT_KEYPRESS:
		ossev.v.cmd = MIDI_KEY_PRESSURE; break;
	case SNDRV_SEQ_EVENT_CONTROLLER:
		ossev.l.cmd = MIDI_CTL_CHANGE; break;
	case SNDRV_SEQ_EVENT_PGMCHANGE:
		ossev.l.cmd = MIDI_PGM_CHANGE; break;
	case SNDRV_SEQ_EVENT_CHANPRESS:
		ossev.l.cmd = MIDI_CHN_PRESSURE; break;
	case SNDRV_SEQ_EVENT_PITCHBEND:
		ossev.l.cmd = MIDI_PITCH_BEND; break;
	default:
		return 0; /* not supported */
	}

	ossev.v.dev = dev;

	switch (ev->type) {
	case SNDRV_SEQ_EVENT_NOTEON:
	case SNDRV_SEQ_EVENT_NOTEOFF:
	case SNDRV_SEQ_EVENT_KEYPRESS:
		ossev.v.code = EV_CHN_VOICE;
		ossev.v.note = ev->data.note.note;
		ossev.v.parm = ev->data.note.velocity;
		ossev.v.chn = ev->data.note.channel;
		break;
	case SNDRV_SEQ_EVENT_CONTROLLER:
	case SNDRV_SEQ_EVENT_PGMCHANGE:
	case SNDRV_SEQ_EVENT_CHANPRESS:
		ossev.l.code = EV_CHN_COMMON;
		ossev.l.p1 = ev->data.control.param;
		ossev.l.val = ev->data.control.value;
		ossev.l.chn = ev->data.control.channel;
		break;
	case SNDRV_SEQ_EVENT_PITCHBEND:
		ossev.l.code = EV_CHN_COMMON;
		ossev.l.val = ev->data.control.value + 8192;
		ossev.l.chn = ev->data.control.channel;
		break;
	}
	
	snd_seq_oss_readq_put_timestamp(dp->readq, ev->time.tick, dp->seq_mode);
	snd_seq_oss_readq_put_event(dp->readq, &ossev);

	return 0;
}

/*
 * decode event and send MIDI bytes to read queue
 */
static int
send_midi_event(struct seq_oss_devinfo *dp, struct snd_seq_event *ev, struct seq_oss_midi *mdev)
{
	char msg[32];
	int len;
	
	snd_seq_oss_readq_put_timestamp(dp->readq, ev->time.tick, dp->seq_mode);
	if (!dp->timer->running)
		len = snd_seq_oss_timer_start(dp->timer);
	if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
		snd_seq_oss_readq_sysex(dp->readq, mdev->seq_device, ev);
		snd_midi_event_reset_decode(mdev->coder);
	} else {
		len = snd_midi_event_decode(mdev->coder, msg, sizeof(msg), ev);
		if (len > 0)
			snd_seq_oss_readq_puts(dp->readq, mdev->seq_device, msg, len);
	}

	return 0;
}


/*
 * dump midi data
 * return 0 : enqueued
 *        non-zero : invalid - ignored
 */
int
snd_seq_oss_midi_putc(struct seq_oss_devinfo *dp, int dev, unsigned char c, struct snd_seq_event *ev)
{
	struct seq_oss_midi *mdev;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return -ENODEV;
	if (snd_midi_event_encode_byte(mdev->coder, c, ev)) {
		snd_seq_oss_fill_addr(dp, ev, mdev->client, mdev->port);
		snd_use_lock_free(&mdev->use_lock);
		return 0;
	}
	snd_use_lock_free(&mdev->use_lock);
	return -EINVAL;
}

/*
 * create OSS compatible midi_info record
 */
int
snd_seq_oss_midi_make_info(struct seq_oss_devinfo *dp, int dev, struct midi_info *inf)
{
	struct seq_oss_midi *mdev;

	if ((mdev = get_mididev(dp, dev)) == NULL)
		return -ENXIO;
	inf->device = dev;
	inf->dev_type = 0; /* FIXME: ?? */
	inf->capabilities = 0; /* FIXME: ?? */
	strlcpy(inf->name, mdev->name, sizeof(inf->name));
	snd_use_lock_free(&mdev->use_lock);
	return 0;
}


#ifdef CONFIG_SND_PROC_FS
/*
 * proc interface
 */
static char *
capmode_str(int val)
{
	val &= PERM_READ|PERM_WRITE;
	if (val == (PERM_READ|PERM_WRITE))
		return "read/write";
	else if (val == PERM_READ)
		return "read";
	else if (val == PERM_WRITE)
		return "write";
	else
		return "none";
}

void
snd_seq_oss_midi_info_read(struct snd_info_buffer *buf)
{
	int i;
	struct seq_oss_midi *mdev;

	snd_iprintf(buf, "\nNumber of MIDI devices: %d\n", max_midi_devs);
	for (i = 0; i < max_midi_devs; i++) {
		snd_iprintf(buf, "\nmidi %d: ", i);
		mdev = get_mdev(i);
		if (mdev == NULL) {
			snd_iprintf(buf, "*empty*\n");
			continue;
		}
		snd_iprintf(buf, "[%s] ALSA port %d:%d\n", mdev->name,
			    mdev->client, mdev->port);
		snd_iprintf(buf, "  capability %s / opened %s\n",
			    capmode_str(mdev->flags),
			    capmode_str(mdev->opened));
		snd_use_lock_free(&mdev->use_lock);
	}
}
#endif /* CONFIG_SND_PROC_FS */