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

#include "seq_oss_synth.h"
#include "seq_oss_midi.h"
#include "../seq_lock.h"
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/nospec.h>

/*
 * constants
 */
#define SNDRV_SEQ_OSS_MAX_SYNTH_NAME    30
#define MAX_SYSEX_BUFLEN                128


/*
 * definition of synth info records
 */

/* synth info */
struct seq_oss_synth {
        int seq_device;

        /* for synth_info */
        int synth_type;
        int synth_subtype;
        int nr_voices;

        char name[SNDRV_SEQ_OSS_MAX_SYNTH_NAME];
        struct snd_seq_oss_callback oper;

        int opened;

        void *private_data;
        snd_use_lock_t use_lock;
};

DEFINE_FREE(seq_oss_synth, struct seq_oss_synth *, if (!IS_ERR_OR_NULL(_T)) snd_use_lock_free(&(_T)->use_lock))

/*
 * device table
 */
static int max_synth_devs;
static struct seq_oss_synth *synth_devs[SNDRV_SEQ_OSS_MAX_SYNTH_DEVS];
static struct seq_oss_synth midi_synth_dev = {
        .seq_device = -1,
        .synth_type = SYNTH_TYPE_MIDI,
        .synth_subtype = 0,
        .nr_voices = 16,
        .name = "MIDI",
};

static DEFINE_SPINLOCK(register_lock);

/*
 * prototypes
 */
static struct seq_oss_synth *get_synthdev(struct seq_oss_devinfo *dp, int dev);
static void reset_channels(struct seq_oss_synthinfo *info);

/*
 * global initialization
 */
void __init
snd_seq_oss_synth_init(void)
{
        snd_use_lock_init(&midi_synth_dev.use_lock);
}

/*
 * registration of the synth device
 */
int
snd_seq_oss_synth_probe(struct snd_seq_device *dev)
{
        int i;
        struct seq_oss_synth *rec;
        struct snd_seq_oss_reg *reg = SNDRV_SEQ_DEVICE_ARGPTR(dev);

        rec = kzalloc(sizeof(*rec), GFP_KERNEL);
        if (!rec)
                return -ENOMEM;
        rec->seq_device = -1;
        rec->synth_type = reg->type;
        rec->synth_subtype = reg->subtype;
        rec->nr_voices = reg->nvoices;
        rec->oper = reg->oper;
        rec->private_data = reg->private_data;
        rec->opened = 0;
        snd_use_lock_init(&rec->use_lock);

        /* copy and truncate the name of synth device */
        strscpy(rec->name, dev->name, sizeof(rec->name));

        /* registration */
        scoped_guard(spinlock_irqsave, &register_lock) {
                for (i = 0; i < max_synth_devs; i++) {
                        if (synth_devs[i] == NULL)
                                break;
                }
                if (i >= max_synth_devs) {
                        if (max_synth_devs >= SNDRV_SEQ_OSS_MAX_SYNTH_DEVS) {
                                pr_err("ALSA: seq_oss: no more synth slot\n");
                                kfree(rec);
                                return -ENOMEM;
                        }
                        max_synth_devs++;
                }
                rec->seq_device = i;
                synth_devs[i] = rec;
        }
        dev->driver_data = rec;
#ifdef SNDRV_OSS_INFO_DEV_SYNTH
        if (i < SNDRV_CARDS)
                snd_oss_info_register(SNDRV_OSS_INFO_DEV_SYNTH, i, rec->name);
#endif
        return 0;
}


void
snd_seq_oss_synth_remove(struct snd_seq_device *dev)
{
        int index;
        struct seq_oss_synth *rec = dev->driver_data;

        scoped_guard(spinlock_irqsave, &register_lock) {
                for (index = 0; index < max_synth_devs; index++) {
                        if (synth_devs[index] == rec)
                                break;
                }
                if (index >= max_synth_devs) {
                        pr_err("ALSA: seq_oss: can't unregister synth\n");
                        return;
                }
                synth_devs[index] = NULL;
                if (index == max_synth_devs - 1) {
                        for (index--; index >= 0; index--) {
                                if (synth_devs[index])
                                        break;
                        }
                        max_synth_devs = index + 1;
                }
        }
#ifdef SNDRV_OSS_INFO_DEV_SYNTH
        if (rec->seq_device < SNDRV_CARDS)
                snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_SYNTH, rec->seq_device);
#endif

        snd_use_lock_sync(&rec->use_lock);
        kfree(rec);
}


/*
 */
static struct seq_oss_synth *
get_sdev(int dev)
{
        struct seq_oss_synth *rec;

        guard(spinlock_irqsave)(&register_lock);
        rec = synth_devs[dev];
        if (rec)
                snd_use_lock_use(&rec->use_lock);
        return rec;
}


/*
 * set up synth tables
 */

void
snd_seq_oss_synth_setup(struct seq_oss_devinfo *dp)
{
        int i;
        struct seq_oss_synthinfo *info;

        dp->max_synthdev = max_synth_devs;
        dp->synth_opened = 0;
        memset(dp->synths, 0, sizeof(dp->synths));
        for (i = 0; i < dp->max_synthdev; i++) {
                struct seq_oss_synth *rec __free(seq_oss_synth) = get_sdev(i);

                if (rec == NULL)
                        continue;
                if (rec->oper.open == NULL || rec->oper.close == NULL)
                        continue;
                info = &dp->synths[i];
                info->arg.app_index = dp->port;
                info->arg.file_mode = dp->file_mode;
                info->arg.seq_mode = dp->seq_mode;
                if (dp->seq_mode == SNDRV_SEQ_OSS_MODE_SYNTH)
                        info->arg.event_passing = SNDRV_SEQ_OSS_PROCESS_EVENTS;
                else
                        info->arg.event_passing = SNDRV_SEQ_OSS_PASS_EVENTS;
                info->opened = 0;
                if (!try_module_get(rec->oper.owner))
                        continue;
                if (rec->oper.open(&info->arg, rec->private_data) < 0) {
                        module_put(rec->oper.owner);
                        continue;
                }
                info->nr_voices = rec->nr_voices;
                if (info->nr_voices > 0) {
                        info->ch = kzalloc_objs(struct seq_oss_chinfo,
                                                info->nr_voices);
                        if (!info->ch) {
                                rec->oper.close(&info->arg);
                                module_put(rec->oper.owner);
                                continue;
                        }
                        reset_channels(info);
                }
                info->opened++;
                rec->opened++;
                dp->synth_opened++;
        }
}


/*
 * set up synth tables for MIDI emulation - /dev/music mode only
 */

void
snd_seq_oss_synth_setup_midi(struct seq_oss_devinfo *dp)
{
        int i;

        if (dp->max_synthdev >= SNDRV_SEQ_OSS_MAX_SYNTH_DEVS)
                return;

        for (i = 0; i < dp->max_mididev; i++) {
                struct seq_oss_synthinfo *info;
                info = &dp->synths[dp->max_synthdev];
                if (snd_seq_oss_midi_open(dp, i, dp->file_mode) < 0)
                        continue;
                info->arg.app_index = dp->port;
                info->arg.file_mode = dp->file_mode;
                info->arg.seq_mode = dp->seq_mode;
                info->arg.private_data = info;
                info->is_midi = 1;
                info->midi_mapped = i;
                info->arg.event_passing = SNDRV_SEQ_OSS_PASS_EVENTS;
                snd_seq_oss_midi_get_addr(dp, i, &info->arg.addr);
                info->opened = 1;
                midi_synth_dev.opened++;
                dp->max_synthdev++;
                if (dp->max_synthdev >= SNDRV_SEQ_OSS_MAX_SYNTH_DEVS)
                        break;
        }
}


/*
 * clean up synth tables
 */

void
snd_seq_oss_synth_cleanup(struct seq_oss_devinfo *dp)
{
        int i;
        struct seq_oss_synthinfo *info;

        if (snd_BUG_ON(dp->max_synthdev > SNDRV_SEQ_OSS_MAX_SYNTH_DEVS))
                return;
        for (i = 0; i < dp->max_synthdev; i++) {
                info = &dp->synths[i];
                if (! info->opened)
                        continue;
                if (info->is_midi) {
                        if (midi_synth_dev.opened > 0) {
                                snd_seq_oss_midi_close(dp, info->midi_mapped);
                                midi_synth_dev.opened--;
                        }
                } else {
                        struct seq_oss_synth *rec __free(seq_oss_synth) =
                                get_sdev(i);

                        if (rec == NULL)
                                continue;
                        if (rec->opened > 0) {
                                rec->oper.close(&info->arg);
                                module_put(rec->oper.owner);
                                rec->opened = 0;
                        }
                }
                kfree(info->ch);
                info->ch = NULL;
        }
        dp->synth_opened = 0;
        dp->max_synthdev = 0;
}

static struct seq_oss_synthinfo *
get_synthinfo_nospec(struct seq_oss_devinfo *dp, int dev)
{
        if (dev < 0 || dev >= dp->max_synthdev)
                return NULL;
        dev = array_index_nospec(dev, SNDRV_SEQ_OSS_MAX_SYNTH_DEVS);
        return &dp->synths[dev];
}

/*
 * return synth device information pointer
 */
static struct seq_oss_synth *
get_synthdev(struct seq_oss_devinfo *dp, int dev)
{
        struct seq_oss_synth *rec;
        struct seq_oss_synthinfo *info = get_synthinfo_nospec(dp, dev);

        if (!info)
                return NULL;
        if (!info->opened)
                return NULL;
        if (info->is_midi) {
                rec = &midi_synth_dev;
                snd_use_lock_use(&rec->use_lock);
        } else {
                rec = get_sdev(dev);
                if (!rec)
                        return NULL;
        }
        if (! rec->opened) {
                snd_use_lock_free(&rec->use_lock);
                return NULL;
        }
        return rec;
}


/*
 * reset note and velocity on each channel.
 */
static void
reset_channels(struct seq_oss_synthinfo *info)
{
        int i;
        if (info->ch == NULL || ! info->nr_voices)
                return;
        for (i = 0; i < info->nr_voices; i++) {
                info->ch[i].note = -1;
                info->ch[i].vel = 0;
        }
}


/*
 * reset synth device:
 * call reset callback.  if no callback is defined, send a heartbeat
 * event to the corresponding port.
 */
void
snd_seq_oss_synth_reset(struct seq_oss_devinfo *dp, int dev)
{
        struct seq_oss_synthinfo *info;

        info = get_synthinfo_nospec(dp, dev);
        if (!info || !info->opened)
                return;
        reset_channels(info);
        if (info->is_midi) {
                if (midi_synth_dev.opened <= 0)
                        return;
                snd_seq_oss_midi_reset(dp, info->midi_mapped);
                /* reopen the device */
                snd_seq_oss_midi_close(dp, dev);
                if (snd_seq_oss_midi_open(dp, info->midi_mapped,
                                          dp->file_mode) < 0) {
                        midi_synth_dev.opened--;
                        info->opened = 0;
                        kfree(info->ch);
                        info->ch = NULL;
                }
                return;
        }

        struct seq_oss_synth *rec __free(seq_oss_synth) =
                get_sdev(dev);
        if (rec == NULL)
                return;
        if (rec->oper.reset) {
                rec->oper.reset(&info->arg);
        } else {
                struct snd_seq_event ev;
                memset(&ev, 0, sizeof(ev));
                snd_seq_oss_fill_addr(dp, &ev, info->arg.addr.client,
                                      info->arg.addr.port);
                ev.type = SNDRV_SEQ_EVENT_RESET;
                snd_seq_oss_dispatch(dp, &ev, 0, 0);
        }
}


/*
 * load a patch record:
 * call load_patch callback function
 */
int
snd_seq_oss_synth_load_patch(struct seq_oss_devinfo *dp, int dev, int fmt,
                            const char __user *buf, int p, int c)
{
        struct seq_oss_synthinfo *info;

        info = get_synthinfo_nospec(dp, dev);
        if (!info)
                return -ENXIO;

        if (info->is_midi)
                return 0;

        struct seq_oss_synth *rec __free(seq_oss_synth) =
                get_synthdev(dp, dev);
        if (!rec)
                return -ENXIO;

        if (rec->oper.load_patch == NULL)
                return -ENXIO;
        else
                return rec->oper.load_patch(&info->arg, fmt, buf, p, c);
}

/*
 * check if the device is valid synth device and return the synth info
 */
struct seq_oss_synthinfo *
snd_seq_oss_synth_info(struct seq_oss_devinfo *dp, int dev)
{
        struct seq_oss_synth *rec __free(seq_oss_synth) =
                get_synthdev(dp, dev);

        if (rec)
                return get_synthinfo_nospec(dp, dev);
        return NULL;
}


/*
 * receive OSS 6 byte sysex packet:
 * the event is filled and prepared for sending immediately
 * (i.e. sysex messages are fragmented)
 */
int
snd_seq_oss_synth_sysex(struct seq_oss_devinfo *dp, int dev, unsigned char *buf, struct snd_seq_event *ev)
{
        unsigned char *p;
        int len = 6;

        p = memchr(buf, 0xff, 6);
        if (p)
                len = p - buf + 1;

        /* copy the data to event record and send it */
        if (snd_seq_oss_synth_addr(dp, dev, ev))
                return -EINVAL;
        ev->flags = SNDRV_SEQ_EVENT_LENGTH_VARIABLE;
        ev->data.ext.len = len;
        ev->data.ext.ptr = buf;
        return 0;
}

/*
 * fill the event source/destination addresses
 */
int
snd_seq_oss_synth_addr(struct seq_oss_devinfo *dp, int dev, struct snd_seq_event *ev)
{
        struct seq_oss_synthinfo *info = snd_seq_oss_synth_info(dp, dev);

        if (!info)
                return -EINVAL;
        snd_seq_oss_fill_addr(dp, ev, info->arg.addr.client,
                              info->arg.addr.port);
        return 0;
}


/*
 * OSS compatible ioctl
 */
int
snd_seq_oss_synth_ioctl(struct seq_oss_devinfo *dp, int dev, unsigned int cmd, unsigned long addr)
{
        struct seq_oss_synthinfo *info;

        info = get_synthinfo_nospec(dp, dev);
        if (!info || info->is_midi)
                return -ENXIO;

        struct seq_oss_synth *rec __free(seq_oss_synth) =
                get_synthdev(dp, dev);
        if (!rec)
                return -ENXIO;
        if (rec->oper.ioctl == NULL)
                return -ENXIO;
        else
                return rec->oper.ioctl(&info->arg, cmd, addr);
}


/*
 * send OSS raw events - SEQ_PRIVATE and SEQ_VOLUME
 */
int
snd_seq_oss_synth_raw_event(struct seq_oss_devinfo *dp, int dev, unsigned char *data, struct snd_seq_event *ev)
{
        struct seq_oss_synthinfo *info;

        info = snd_seq_oss_synth_info(dp, dev);
        if (!info || info->is_midi)
                return -ENXIO;
        ev->type = SNDRV_SEQ_EVENT_OSS;
        memcpy(ev->data.raw8.d, data, 8);
        return snd_seq_oss_synth_addr(dp, dev, ev);
}


/*
 * create OSS compatible synth_info record
 */
int
snd_seq_oss_synth_make_info(struct seq_oss_devinfo *dp, int dev, struct synth_info *inf)
{
        struct seq_oss_synthinfo *info = get_synthinfo_nospec(dp, dev);

        if (!info)
                return -ENXIO;

        if (info->is_midi) {
                struct midi_info minf;
                if (snd_seq_oss_midi_make_info(dp, info->midi_mapped, &minf))
                        return -ENXIO;
                inf->synth_type = SYNTH_TYPE_MIDI;
                inf->synth_subtype = 0;
                inf->nr_voices = 16;
                inf->device = dev;
                strscpy(inf->name, minf.name, sizeof(inf->name));
        } else {
                struct seq_oss_synth *rec __free(seq_oss_synth) =
                        get_synthdev(dp, dev);

                if (!rec)
                        return -ENXIO;
                inf->synth_type = rec->synth_type;
                inf->synth_subtype = rec->synth_subtype;
                inf->nr_voices = rec->nr_voices;
                inf->device = dev;
                strscpy(inf->name, rec->name, sizeof(inf->name));
        }
        return 0;
}


#ifdef CONFIG_SND_PROC_FS
/*
 * proc interface
 */
void
snd_seq_oss_synth_info_read(struct snd_info_buffer *buf)
{
        int i;

        snd_iprintf(buf, "\nNumber of synth devices: %d\n", max_synth_devs);
        for (i = 0; i < max_synth_devs; i++) {
                snd_iprintf(buf, "\nsynth %d: ", i);
                struct seq_oss_synth *rec __free(seq_oss_synth) =
                        get_sdev(i);
                if (rec == NULL) {
                        snd_iprintf(buf, "*empty*\n");
                        continue;
                }
                snd_iprintf(buf, "[%s]\n", rec->name);
                snd_iprintf(buf, "  type 0x%x : subtype 0x%x : voices %d\n",
                            rec->synth_type, rec->synth_subtype,
                            rec->nr_voices);
                snd_iprintf(buf, "  capabilities : ioctl %s / load_patch %s\n",
                            str_enabled_disabled((long)rec->oper.ioctl),
                            str_enabled_disabled((long)rec->oper.load_patch));
        }
}
#endif /* CONFIG_SND_PROC_FS */