// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OSS compatible sequencer driver
 *
 * open/close and reset interface
 *
 * Copyright (C) 1998-1999 Takashi Iwai <tiwai@suse.de>
 */

#include "seq_oss_device.h"
#include "seq_oss_synth.h"
#include "seq_oss_midi.h"
#include "seq_oss_writeq.h"
#include "seq_oss_readq.h"
#include "seq_oss_timer.h"
#include "seq_oss_event.h"
#include <linux/init.h>
#include <linux/export.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

/*
 * common variables
 */
static int maxqlen = SNDRV_SEQ_OSS_MAX_QLEN;
module_param(maxqlen, int, 0444);
MODULE_PARM_DESC(maxqlen, "maximum queue length");

static int system_client = -1; /* ALSA sequencer client number */
static int system_port = -1;

static int num_clients;
static struct seq_oss_devinfo *client_table[SNDRV_SEQ_OSS_MAX_CLIENTS];


/*
 * prototypes
 */
static int receive_announce(struct snd_seq_event *ev, int direct, void *private, int atomic, int hop);
static int translate_mode(struct file *file);
static int create_port(struct seq_oss_devinfo *dp);
static int delete_port(struct seq_oss_devinfo *dp);
static int alloc_seq_queue(struct seq_oss_devinfo *dp);
static int delete_seq_queue(int queue);
static void free_devinfo(void *private);

#define call_ctl(type,rec) snd_seq_kernel_client_ctl(system_client, type, rec)


/* call snd_seq_oss_midi_lookup_ports() asynchronously */
static void async_call_lookup_ports(struct work_struct *work)
{
        snd_seq_oss_midi_lookup_ports(system_client);
}

static DECLARE_WORK(async_lookup_work, async_call_lookup_ports);

/*
 * create sequencer client for OSS sequencer
 */
int __init
snd_seq_oss_create_client(void)
{
        int rc;
        struct snd_seq_port_callback port_callback;
        struct snd_seq_port_info *port __free(kfree) =
                kzalloc_obj(*port);

        if (!port)
                return -ENOMEM;

        /* create ALSA client */
        rc = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_OSS,
                                          "OSS sequencer");
        if (rc < 0)
                return rc;

        system_client = rc;

        /* create announcement receiver port */
        strscpy(port->name, "Receiver");
        port->addr.client = system_client;
        port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* receive only */
        port->type = 0;

        memset(&port_callback, 0, sizeof(port_callback));
        /* don't set port_callback.owner here. otherwise the module counter
         * is incremented and we can no longer release the module..
         */
        port_callback.event_input = receive_announce;
        port->kernel = &port_callback;
        
        if (call_ctl(SNDRV_SEQ_IOCTL_CREATE_PORT, port) >= 0) {
                struct snd_seq_port_subscribe subs;

                system_port = port->addr.port;
                memset(&subs, 0, sizeof(subs));
                subs.sender.client = SNDRV_SEQ_CLIENT_SYSTEM;
                subs.sender.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
                subs.dest.client = system_client;
                subs.dest.port = system_port;
                call_ctl(SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT, &subs);
        }

        /* look up midi devices */
        schedule_work(&async_lookup_work);

        return 0;
}


/*
 * receive announcement from system port, and check the midi device
 */
static int
receive_announce(struct snd_seq_event *ev, int direct, void *private, int atomic, int hop)
{
        struct snd_seq_port_info pinfo;

        if (atomic)
                return 0; /* it must not happen */

        switch (ev->type) {
        case SNDRV_SEQ_EVENT_PORT_START:
        case SNDRV_SEQ_EVENT_PORT_CHANGE:
                if (ev->data.addr.client == system_client)
                        break; /* ignore myself */
                memset(&pinfo, 0, sizeof(pinfo));
                pinfo.addr = ev->data.addr;
                if (call_ctl(SNDRV_SEQ_IOCTL_GET_PORT_INFO, &pinfo) >= 0)
                        snd_seq_oss_midi_check_new_port(&pinfo);
                break;

        case SNDRV_SEQ_EVENT_PORT_EXIT:
                if (ev->data.addr.client == system_client)
                        break; /* ignore myself */
                snd_seq_oss_midi_check_exit_port(ev->data.addr.client,
                                                ev->data.addr.port);
                break;
        }
        return 0;
}


/*
 * delete OSS sequencer client
 */
int
snd_seq_oss_delete_client(void)
{
        cancel_work_sync(&async_lookup_work);
        if (system_client >= 0)
                snd_seq_delete_kernel_client(system_client);

        snd_seq_oss_midi_clear_all();

        return 0;
}


/*
 * open sequencer device
 */
int
snd_seq_oss_open(struct file *file, int level)
{
        int i, rc;
        struct seq_oss_devinfo *dp;

        dp = kzalloc_obj(*dp);
        if (!dp)
                return -ENOMEM;

        dp->cseq = system_client;
        dp->port = -1;
        dp->queue = -1;

        for (i = 0; i < SNDRV_SEQ_OSS_MAX_CLIENTS; i++) {
                if (client_table[i] == NULL)
                        break;
        }

        dp->index = i;
        if (i >= SNDRV_SEQ_OSS_MAX_CLIENTS) {
                pr_debug("ALSA: seq_oss: too many applications\n");
                rc = -ENOMEM;
                goto _error;
        }

        /* look up synth and midi devices */
        snd_seq_oss_synth_setup(dp);
        snd_seq_oss_midi_setup(dp);

        if (dp->synth_opened == 0 && dp->max_mididev == 0) {
                /* pr_err("ALSA: seq_oss: no device found\n"); */
                rc = -ENODEV;
                goto _error;
        }

        /* create port */
        rc = create_port(dp);
        if (rc < 0) {
                pr_err("ALSA: seq_oss: can't create port\n");
                goto _error;
        }

        /* allocate queue */
        rc = alloc_seq_queue(dp);
        if (rc < 0)
                goto _error;

        /* set address */
        dp->addr.client = dp->cseq;
        dp->addr.port = dp->port;
        /*dp->addr.queue = dp->queue;*/
        /*dp->addr.channel = 0;*/

        dp->seq_mode = level;

        /* set up file mode */
        dp->file_mode = translate_mode(file);

        /* initialize read queue */
        if (is_read_mode(dp->file_mode)) {
                dp->readq = snd_seq_oss_readq_new(dp, maxqlen);
                if (!dp->readq) {
                        rc = -ENOMEM;
                        goto _error;
                }
        }

        /* initialize write queue */
        if (is_write_mode(dp->file_mode)) {
                dp->writeq = snd_seq_oss_writeq_new(dp, maxqlen);
                if (!dp->writeq) {
                        rc = -ENOMEM;
                        goto _error;
                }
        }

        /* initialize timer */
        dp->timer = snd_seq_oss_timer_new(dp);
        if (!dp->timer) {
                pr_err("ALSA: seq_oss: can't alloc timer\n");
                rc = -ENOMEM;
                goto _error;
        }

        /* set private data pointer */
        file->private_data = dp;

        /* set up for mode2 */
        if (level == SNDRV_SEQ_OSS_MODE_MUSIC)
                snd_seq_oss_synth_setup_midi(dp);
        else if (is_read_mode(dp->file_mode))
                snd_seq_oss_midi_open_all(dp, SNDRV_SEQ_OSS_FILE_READ);

        client_table[dp->index] = dp;
        num_clients++;

        return 0;

 _error:
        snd_seq_oss_synth_cleanup(dp);
        snd_seq_oss_midi_cleanup(dp);
        delete_seq_queue(dp->queue);
        delete_port(dp);

        return rc;
}

/*
 * translate file flags to private mode
 */
static int
translate_mode(struct file *file)
{
        int file_mode = 0;
        if ((file->f_flags & O_ACCMODE) != O_RDONLY)
                file_mode |= SNDRV_SEQ_OSS_FILE_WRITE;
        if ((file->f_flags & O_ACCMODE) != O_WRONLY)
                file_mode |= SNDRV_SEQ_OSS_FILE_READ;
        if (file->f_flags & O_NONBLOCK)
                file_mode |= SNDRV_SEQ_OSS_FILE_NONBLOCK;
        return file_mode;
}


/*
 * create sequencer port
 */
static int
create_port(struct seq_oss_devinfo *dp)
{
        int rc;
        struct snd_seq_port_info port;
        struct snd_seq_port_callback callback;

        memset(&port, 0, sizeof(port));
        port.addr.client = dp->cseq;
        sprintf(port.name, "Sequencer-%d", dp->index);
        port.capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_WRITE; /* no subscription */
        port.type = SNDRV_SEQ_PORT_TYPE_SPECIFIC;
        port.midi_channels = 128;
        port.synth_voices = 128;

        memset(&callback, 0, sizeof(callback));
        callback.owner = THIS_MODULE;
        callback.private_data = dp;
        callback.event_input = snd_seq_oss_event_input;
        callback.private_free = free_devinfo;
        port.kernel = &callback;

        rc = call_ctl(SNDRV_SEQ_IOCTL_CREATE_PORT, &port);
        if (rc < 0)
                return rc;

        dp->port = port.addr.port;

        return 0;
}

/*
 * delete ALSA port
 */
static int
delete_port(struct seq_oss_devinfo *dp)
{
        if (dp->port < 0) {
                kfree(dp);
                return 0;
        }

        return snd_seq_event_port_detach(dp->cseq, dp->port);
}

/*
 * allocate a queue
 */
static int
alloc_seq_queue(struct seq_oss_devinfo *dp)
{
        struct snd_seq_queue_info qinfo;
        int rc;

        memset(&qinfo, 0, sizeof(qinfo));
        qinfo.owner = system_client;
        qinfo.locked = 1;
        strscpy(qinfo.name, "OSS Sequencer Emulation");
        rc = call_ctl(SNDRV_SEQ_IOCTL_CREATE_QUEUE, &qinfo);
        if (rc < 0)
                return rc;
        dp->queue = qinfo.queue;
        return 0;
}

/*
 * release queue
 */
static int
delete_seq_queue(int queue)
{
        struct snd_seq_queue_info qinfo;
        int rc;

        if (queue < 0)
                return 0;
        memset(&qinfo, 0, sizeof(qinfo));
        qinfo.queue = queue;
        rc = call_ctl(SNDRV_SEQ_IOCTL_DELETE_QUEUE, &qinfo);
        if (rc < 0)
                pr_err("ALSA: seq_oss: unable to delete queue %d (%d)\n", queue, rc);
        return rc;
}


/*
 * free device informations - private_free callback of port
 */
static void
free_devinfo(void *private)
{
        struct seq_oss_devinfo *dp = (struct seq_oss_devinfo *)private;

        snd_seq_oss_timer_delete(dp->timer);
                
        snd_seq_oss_writeq_delete(dp->writeq);

        snd_seq_oss_readq_delete(dp->readq);
        
        kfree(dp);
}


/*
 * close sequencer device
 */
void
snd_seq_oss_release(struct seq_oss_devinfo *dp)
{
        int queue;

        client_table[dp->index] = NULL;
        num_clients--;

        snd_seq_oss_reset(dp);

        snd_seq_oss_synth_cleanup(dp);
        snd_seq_oss_midi_cleanup(dp);

        /* clear slot */
        queue = dp->queue;
        if (dp->port >= 0)
                delete_port(dp);
        delete_seq_queue(queue);
}


/*
 * reset sequencer devices
 */
void
snd_seq_oss_reset(struct seq_oss_devinfo *dp)
{
        int i;

        /* reset all synth devices */
        for (i = 0; i < dp->max_synthdev; i++)
                snd_seq_oss_synth_reset(dp, i);

        /* reset all midi devices */
        if (dp->seq_mode != SNDRV_SEQ_OSS_MODE_MUSIC) {
                for (i = 0; i < dp->max_mididev; i++)
                        snd_seq_oss_midi_reset(dp, i);
        }

        /* remove queues */
        if (dp->readq)
                snd_seq_oss_readq_clear(dp->readq);
        if (dp->writeq)
                snd_seq_oss_writeq_clear(dp->writeq);

        /* reset timer */
        snd_seq_oss_timer_stop(dp->timer);
}

#ifdef CONFIG_SND_PROC_FS
/*
 * misc. functions for proc interface
 */
static const char *
filemode_str(int val)
{
        static const char * const str[] = {
                "none", "read", "write", "read/write",
        };
        return str[val & SNDRV_SEQ_OSS_FILE_ACMODE];
}


/*
 * proc interface
 */
void
snd_seq_oss_system_info_read(struct snd_info_buffer *buf)
{
        int i;
        struct seq_oss_devinfo *dp;

        snd_iprintf(buf, "ALSA client number %d\n", system_client);
        snd_iprintf(buf, "ALSA receiver port %d\n", system_port);

        snd_iprintf(buf, "\nNumber of applications: %d\n", num_clients);
        for (i = 0; i < num_clients; i++) {
                snd_iprintf(buf, "\nApplication %d: ", i);
                dp = client_table[i];
                if (!dp) {
                        snd_iprintf(buf, "*empty*\n");
                        continue;
                }
                snd_iprintf(buf, "port %d : queue %d\n", dp->port, dp->queue);
                snd_iprintf(buf, "  sequencer mode = %s : file open mode = %s\n",
                            (dp->seq_mode ? "music" : "synth"),
                            filemode_str(dp->file_mode));
                if (dp->seq_mode)
                        snd_iprintf(buf, "  timer tempo = %d, timebase = %d\n",
                                    dp->timer->oss_tempo, dp->timer->oss_timebase);
                snd_iprintf(buf, "  max queue length %d\n", maxqlen);
                if (is_read_mode(dp->file_mode) && dp->readq)
                        snd_seq_oss_readq_info_read(dp->readq, buf);
        }
}
#endif /* CONFIG_SND_PROC_FS */