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hostaudio_kern.c

/*
 * Copyright (C) 2002 Steve Schmidtke
 * Licensed under the GPL
 */

#include "linux/fs.h"
#include "linux/module.h"
#include "linux/slab.h"
#include "linux/sound.h"
#include "linux/soundcard.h"
#include "asm/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"

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

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

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

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

#else /*MODULE*/

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

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

#endif

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

      err = -EFAULT;
      if (copy_from_user(kbuf, buffer, count))
            goto out;

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

 out:
      kfree(kbuf);
      return err;
}

static unsigned int hostaudio_poll(struct file *file,
                           struct poll_table_struct *wait)
{
      unsigned int mask = 0;

#ifdef DEBUG
      printk(KERN_DEBUG "hostaudio: poll called (unimplemented)\n");
#endif

      return mask;
}

static int hostaudio_ioctl(struct inode *inode, 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
      printk(KERN_DEBUG "hostaudio: open called (host: %s)\n", dsp);
#endif

      state = kmalloc(sizeof(struct hostaudio_state), GFP_KERNEL);
      if (state == NULL)
            return -ENOMEM;

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

      ret = os_open_file(dsp, of_set_rw(OPENFLAGS(), r, w), 0);
      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 int hostmixer_ioctl_mixdev(struct inode *inode, 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(sizeof(struct hostmixer_state), GFP_KERNEL);
      if (state == NULL)
            return -ENOMEM;

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

      ret = os_open_file(mixer, of_set_rw(OPENFLAGS(), r, w), 0);

      if (ret < 0) {
            printk(KERN_ERR "hostaudio_open_mixdev failed to open '%s', "
                   "err = %d\n", dsp, -ret);
            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,
      .llseek         = no_llseek,
      .read           = hostaudio_read,
      .write          = hostaudio_write,
      .poll           = hostaudio_poll,
      .ioctl          = hostaudio_ioctl,
      .mmap           = NULL,
      .open           = hostaudio_open,
      .release        = hostaudio_release,
};

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

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)
{
      printk(KERN_INFO "UML Audio Relay (host dsp = %s, host mixer = %s)\n",
             dsp, mixer);

      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);

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