hwdep.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * HWDEP Interface for HD-audio codec
 *
 * Copyright (c) 2007 Takashi Iwai <[email protected]>
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/nospec.h>
#include <sound/core.h>
#include <sound/hda_codec.h>
#include "hda_local.h"
#include <sound/hda_hwdep.h>
#include <sound/minors.h>

/*
 * write/read an out-of-bound verb
 */
static int verb_write_ioctl(struct hda_codec *codec,
			    struct hda_verb_ioctl __user *arg)
{
	u32 verb, res;

	if (get_user(verb, &arg->verb))
		return -EFAULT;
	res = snd_hda_codec_read(codec, verb >> 24, 0,
				 (verb >> 8) & 0xffff, verb & 0xff);
	if (put_user(res, &arg->res))
		return -EFAULT;
	return 0;
}

static int get_wcap_ioctl(struct hda_codec *codec,
			  struct hda_verb_ioctl __user *arg)
{
	u32 verb, res;
	
	if (get_user(verb, &arg->verb))
		return -EFAULT;
	/* open-code get_wcaps(verb>>24) with nospec */
	verb >>= 24;
	if (verb < codec->core.start_nid ||
	    verb >= codec->core.start_nid + codec->core.num_nodes) {
		res = 0;
	} else {
		verb -= codec->core.start_nid;
		verb = array_index_nospec(verb, codec->core.num_nodes);
		res = codec->wcaps[verb];
	}
	if (put_user(res, &arg->res))
		return -EFAULT;
	return 0;
}


/*
 */
static int hda_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
			   unsigned int cmd, unsigned long arg)
{
	struct hda_codec *codec = hw->private_data;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	case HDA_IOCTL_PVERSION:
		return put_user(HDA_HWDEP_VERSION, (int __user *)argp);
	case HDA_IOCTL_VERB_WRITE:
		return verb_write_ioctl(codec, argp);
	case HDA_IOCTL_GET_WCAP:
		return get_wcap_ioctl(codec, argp);
	}
	return -ENOIOCTLCMD;
}

#ifdef CONFIG_COMPAT
static int hda_hwdep_ioctl_compat(struct snd_hwdep *hw, struct file *file,
				  unsigned int cmd, unsigned long arg)
{
	return hda_hwdep_ioctl(hw, file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static int hda_hwdep_open(struct snd_hwdep *hw, struct file *file)
{
	if (!capable(CAP_SYS_RAWIO))
		return -EACCES;
	return 0;
}

int snd_hda_create_hwdep(struct hda_codec *codec)
{
	char hwname[16];
	struct snd_hwdep *hwdep;
	int err;

	sprintf(hwname, "HDA Codec %d", codec->addr);
	err = snd_hwdep_new(codec->card, hwname, codec->addr, &hwdep);
	if (err < 0)
		return err;
	codec->hwdep = hwdep;
	sprintf(hwdep->name, "HDA Codec %d", codec->addr);
	hwdep->iface = SNDRV_HWDEP_IFACE_HDA;
	hwdep->private_data = codec;
	hwdep->exclusive = 1;

	hwdep->ops.open = hda_hwdep_open;
	hwdep->ops.ioctl = hda_hwdep_ioctl;
#ifdef CONFIG_COMPAT
	hwdep->ops.ioctl_compat = hda_hwdep_ioctl_compat;
#endif

	/* for sysfs */
	hwdep->dev->groups = snd_hda_dev_attr_groups;
	dev_set_drvdata(hwdep->dev, codec);

	return 0;
}