// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2002 Steve Schmidtke
 */

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sound.h>
#include <linux/soundcard.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <init.h>
#include <os.h>

struct hostaudio_state {
        int fd;
};

struct hostmixer_state {
        int fd;
};

#define HOSTAUDIO_DEV_DSP "/dev/sound/dsp"
#define HOSTAUDIO_DEV_MIXER "/dev/sound/mixer"

/*
 * Changed either at boot time or module load time.  At boot, this is
 * single-threaded; at module load, multiple modules would each have
 * their own copy of these variables.
 */
static char *dsp = HOSTAUDIO_DEV_DSP;
static char *mixer = HOSTAUDIO_DEV_MIXER;

#define DSP_HELP \
"    This is used to specify the host dsp device to the hostaudio driver.\n" \
"    The default is \"" HOSTAUDIO_DEV_DSP "\".\n\n"

#define MIXER_HELP \
"    This is used to specify the host mixer device to the hostaudio driver.\n"\
"    The default is \"" HOSTAUDIO_DEV_MIXER "\".\n\n"

module_param(dsp, charp, 0644);
MODULE_PARM_DESC(dsp, DSP_HELP);
module_param(mixer, charp, 0644);
MODULE_PARM_DESC(mixer, MIXER_HELP);

#ifndef MODULE
static int set_dsp(char *name, int *add)
{
        *add = 0;
        dsp = name;
        return 0;
}

__uml_setup("dsp=", set_dsp, "dsp=<dsp device>\n" DSP_HELP);

static int set_mixer(char *name, int *add)
{
        *add = 0;
        mixer = name;
        return 0;
}

__uml_setup("mixer=", set_mixer, "mixer=<mixer device>\n" MIXER_HELP);
#endif

static DEFINE_MUTEX(hostaudio_mutex);

/* /dev/dsp file operations */

static ssize_t hostaudio_read(struct file *file, char __user *buffer,
                              size_t count, loff_t *ppos)
{
        struct hostaudio_state *state = file->private_data;
        void *kbuf;
        int err;

#ifdef DEBUG
        printk(KERN_DEBUG "hostaudio: read called, count = %d\n", count);
#endif

        kbuf = kmalloc(count, GFP_KERNEL);
        if (kbuf == NULL)
                return -ENOMEM;

        err = os_read_file(state->fd, kbuf, count);
        if (err < 0)
                goto out;

        if (copy_to_user(buffer, kbuf, err))
                err = -EFAULT;

out:
        kfree(kbuf);
        return err;
}

static ssize_t hostaudio_write(struct file *file, const char __user *buffer,
                               size_t count, loff_t *ppos)
{
        struct hostaudio_state *state = file->private_data;
        void *kbuf;
        int err;

#ifdef DEBUG
        printk(KERN_DEBUG "hostaudio: write called, count = %d\n", count);
#endif

        kbuf = memdup_user(buffer, count);
        if (IS_ERR(kbuf))
                return PTR_ERR(kbuf);

        err = os_write_file(state->fd, kbuf, count);
        if (err < 0)
                goto out;
        *ppos += err;

 out:
        kfree(kbuf);
        return err;
}

static __poll_t hostaudio_poll(struct file *file,
                                struct poll_table_struct *wait)
{
#ifdef DEBUG
        printk(KERN_DEBUG "hostaudio: poll called (unimplemented)\n");
#endif

        return 0;
}

static long hostaudio_ioctl(struct file *file,
                           unsigned int cmd, unsigned long arg)
{
        struct hostaudio_state *state = file->private_data;
        unsigned long data = 0;
        int err;

#ifdef DEBUG
        printk(KERN_DEBUG "hostaudio: ioctl called, cmd = %u\n", cmd);
#endif
        switch(cmd){
        case SNDCTL_DSP_SPEED:
        case SNDCTL_DSP_STEREO:
        case SNDCTL_DSP_GETBLKSIZE:
        case SNDCTL_DSP_CHANNELS:
        case SNDCTL_DSP_SUBDIVIDE:
        case SNDCTL_DSP_SETFRAGMENT:
                if (get_user(data, (int __user *) arg))
                        return -EFAULT;
                break;
        default:
                break;
        }

        err = os_ioctl_generic(state->fd, cmd, (unsigned long) &data);

        switch(cmd){
        case SNDCTL_DSP_SPEED:
        case SNDCTL_DSP_STEREO:
        case SNDCTL_DSP_GETBLKSIZE:
        case SNDCTL_DSP_CHANNELS:
        case SNDCTL_DSP_SUBDIVIDE:
        case SNDCTL_DSP_SETFRAGMENT:
                if (put_user(data, (int __user *) arg))
                        return -EFAULT;
                break;
        default:
                break;
        }

        return err;
}

static int hostaudio_open(struct inode *inode, struct file *file)
{
        struct hostaudio_state *state;
        int r = 0, w = 0;
        int ret;

#ifdef DEBUG
        kernel_param_lock(THIS_MODULE);
        printk(KERN_DEBUG "hostaudio: open called (host: %s)\n", dsp);
        kernel_param_unlock(THIS_MODULE);
#endif

        state = kmalloc_obj(struct hostaudio_state);
        if (state == NULL)
                return -ENOMEM;

        if (file->f_mode & FMODE_READ)
                r = 1;
        if (file->f_mode & FMODE_WRITE)
                w = 1;

        kernel_param_lock(THIS_MODULE);
        mutex_lock(&hostaudio_mutex);
        ret = os_open_file(dsp, of_set_rw(OPENFLAGS(), r, w), 0);
        mutex_unlock(&hostaudio_mutex);
        kernel_param_unlock(THIS_MODULE);

        if (ret < 0) {
                kfree(state);
                return ret;
        }
        state->fd = ret;
        file->private_data = state;
        return 0;
}

static int hostaudio_release(struct inode *inode, struct file *file)
{
        struct hostaudio_state *state = file->private_data;

#ifdef DEBUG
        printk(KERN_DEBUG "hostaudio: release called\n");
#endif
        os_close_file(state->fd);
        kfree(state);

        return 0;
}

/* /dev/mixer file operations */

static long hostmixer_ioctl_mixdev(struct file *file,
                                  unsigned int cmd, unsigned long arg)
{
        struct hostmixer_state *state = file->private_data;

#ifdef DEBUG
        printk(KERN_DEBUG "hostmixer: ioctl called\n");
#endif

        return os_ioctl_generic(state->fd, cmd, arg);
}

static int hostmixer_open_mixdev(struct inode *inode, struct file *file)
{
        struct hostmixer_state *state;
        int r = 0, w = 0;
        int ret;

#ifdef DEBUG
        printk(KERN_DEBUG "hostmixer: open called (host: %s)\n", mixer);
#endif

        state = kmalloc_obj(struct hostmixer_state);
        if (state == NULL)
                return -ENOMEM;

        if (file->f_mode & FMODE_READ)
                r = 1;
        if (file->f_mode & FMODE_WRITE)
                w = 1;

        kernel_param_lock(THIS_MODULE);
        mutex_lock(&hostaudio_mutex);
        ret = os_open_file(mixer, of_set_rw(OPENFLAGS(), r, w), 0);
        mutex_unlock(&hostaudio_mutex);
        kernel_param_unlock(THIS_MODULE);

        if (ret < 0) {
                kernel_param_lock(THIS_MODULE);
                printk(KERN_ERR "hostaudio_open_mixdev failed to open '%s', "
                       "err = %d\n", dsp, -ret);
                kernel_param_unlock(THIS_MODULE);
                kfree(state);
                return ret;
        }

        file->private_data = state;
        return 0;
}

static int hostmixer_release(struct inode *inode, struct file *file)
{
        struct hostmixer_state *state = file->private_data;

#ifdef DEBUG
        printk(KERN_DEBUG "hostmixer: release called\n");
#endif

        os_close_file(state->fd);
        kfree(state);

        return 0;
}

/* kernel module operations */

static const struct file_operations hostaudio_fops = {
        .owner          = THIS_MODULE,
        .read           = hostaudio_read,
        .write          = hostaudio_write,
        .poll           = hostaudio_poll,
        .unlocked_ioctl = hostaudio_ioctl,
        .compat_ioctl   = compat_ptr_ioctl,
        .mmap           = NULL,
        .open           = hostaudio_open,
        .release        = hostaudio_release,
};

static const struct file_operations hostmixer_fops = {
        .owner          = THIS_MODULE,
        .unlocked_ioctl = hostmixer_ioctl_mixdev,
        .open           = hostmixer_open_mixdev,
        .release        = hostmixer_release,
};

static struct {
        int dev_audio;
        int dev_mixer;
} module_data;

MODULE_AUTHOR("Steve Schmidtke");
MODULE_DESCRIPTION("UML Audio Relay");
MODULE_LICENSE("GPL");

static int __init hostaudio_init_module(void)
{
        kernel_param_lock(THIS_MODULE);
        printk(KERN_INFO "UML Audio Relay (host dsp = %s, host mixer = %s)\n",
               dsp, mixer);
        kernel_param_unlock(THIS_MODULE);

        module_data.dev_audio = register_sound_dsp(&hostaudio_fops, -1);
        if (module_data.dev_audio < 0) {
                printk(KERN_ERR "hostaudio: couldn't register DSP device!\n");
                return -ENODEV;
        }

        module_data.dev_mixer = register_sound_mixer(&hostmixer_fops, -1);
        if (module_data.dev_mixer < 0) {
                printk(KERN_ERR "hostmixer: couldn't register mixer "
                       "device!\n");
                unregister_sound_dsp(module_data.dev_audio);
                return -ENODEV;
        }

        return 0;
}

static void __exit hostaudio_cleanup_module (void)
{
        unregister_sound_mixer(module_data.dev_mixer);
        unregister_sound_dsp(module_data.dev_audio);
}

module_init(hostaudio_init_module);
module_exit(hostaudio_cleanup_module);