/*
 * OSS compatible sequencer driver
 *
 * MIDI device handlers
 *
 * Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#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);
        } 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) > 0) {
                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 */