linux/include/sound/control.h
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   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2#ifndef __SOUND_CONTROL_H
   3#define __SOUND_CONTROL_H
   4
   5/*
   6 *  Header file for control interface
   7 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   8 */
   9
  10#include <linux/wait.h>
  11#include <linux/nospec.h>
  12#include <sound/asound.h>
  13
  14#define snd_kcontrol_chip(kcontrol) ((kcontrol)->private_data)
  15
  16struct snd_kcontrol;
  17typedef int (snd_kcontrol_info_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_info * uinfo);
  18typedef int (snd_kcontrol_get_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_value * ucontrol);
  19typedef int (snd_kcontrol_put_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_value * ucontrol);
  20typedef int (snd_kcontrol_tlv_rw_t)(struct snd_kcontrol *kcontrol,
  21                                    int op_flag, /* SNDRV_CTL_TLV_OP_XXX */
  22                                    unsigned int size,
  23                                    unsigned int __user *tlv);
  24
  25/* internal flag for skipping validations */
  26#ifdef CONFIG_SND_CTL_VALIDATION
  27#define SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK        (1 << 27)
  28#define snd_ctl_skip_validation(info) \
  29        ((info)->access & SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK)
  30#else
  31#define SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK        0
  32#define snd_ctl_skip_validation(info)           true
  33#endif
  34
  35enum {
  36        SNDRV_CTL_TLV_OP_READ = 0,
  37        SNDRV_CTL_TLV_OP_WRITE = 1,
  38        SNDRV_CTL_TLV_OP_CMD = -1,
  39};
  40
  41struct snd_kcontrol_new {
  42        snd_ctl_elem_iface_t iface;     /* interface identifier */
  43        unsigned int device;            /* device/client number */
  44        unsigned int subdevice;         /* subdevice (substream) number */
  45        const unsigned char *name;      /* ASCII name of item */
  46        unsigned int index;             /* index of item */
  47        unsigned int access;            /* access rights */
  48        unsigned int count;             /* count of same elements */
  49        snd_kcontrol_info_t *info;
  50        snd_kcontrol_get_t *get;
  51        snd_kcontrol_put_t *put;
  52        union {
  53                snd_kcontrol_tlv_rw_t *c;
  54                const unsigned int *p;
  55        } tlv;
  56        unsigned long private_value;
  57};
  58
  59struct snd_kcontrol_volatile {
  60        struct snd_ctl_file *owner;     /* locked */
  61        unsigned int access;    /* access rights */
  62};
  63
  64struct snd_kcontrol {
  65        struct list_head list;          /* list of controls */
  66        struct snd_ctl_elem_id id;
  67        unsigned int count;             /* count of same elements */
  68        snd_kcontrol_info_t *info;
  69        snd_kcontrol_get_t *get;
  70        snd_kcontrol_put_t *put;
  71        union {
  72                snd_kcontrol_tlv_rw_t *c;
  73                const unsigned int *p;
  74        } tlv;
  75        unsigned long private_value;
  76        void *private_data;
  77        void (*private_free)(struct snd_kcontrol *kcontrol);
  78        struct snd_kcontrol_volatile vd[];      /* volatile data */
  79};
  80
  81#define snd_kcontrol(n) list_entry(n, struct snd_kcontrol, list)
  82
  83struct snd_kctl_event {
  84        struct list_head list;  /* list of events */
  85        struct snd_ctl_elem_id id;
  86        unsigned int mask;
  87};
  88
  89#define snd_kctl_event(n) list_entry(n, struct snd_kctl_event, list)
  90
  91struct pid;
  92
  93enum {
  94        SND_CTL_SUBDEV_PCM,
  95        SND_CTL_SUBDEV_RAWMIDI,
  96        SND_CTL_SUBDEV_ITEMS,
  97};
  98
  99struct snd_ctl_file {
 100        struct list_head list;          /* list of all control files */
 101        struct snd_card *card;
 102        struct pid *pid;
 103        int preferred_subdevice[SND_CTL_SUBDEV_ITEMS];
 104        wait_queue_head_t change_sleep;
 105        spinlock_t read_lock;
 106        struct fasync_struct *fasync;
 107        int subscribed;                 /* read interface is activated */
 108        struct list_head events;        /* waiting events for read */
 109};
 110
 111#define snd_ctl_file(n) list_entry(n, struct snd_ctl_file, list)
 112
 113typedef int (*snd_kctl_ioctl_func_t) (struct snd_card * card,
 114                                      struct snd_ctl_file * control,
 115                                      unsigned int cmd, unsigned long arg);
 116
 117void snd_ctl_notify(struct snd_card * card, unsigned int mask, struct snd_ctl_elem_id * id);
 118
 119struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new * kcontrolnew, void * private_data);
 120void snd_ctl_free_one(struct snd_kcontrol * kcontrol);
 121int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol);
 122int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);
 123int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, bool add_on_replace);
 124int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);
 125int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);
 126int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 127                        int active);
 128struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid);
 129struct snd_kcontrol *snd_ctl_find_id(struct snd_card * card, struct snd_ctl_elem_id *id);
 130
 131int snd_ctl_create(struct snd_card *card);
 132
 133int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn);
 134int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn);
 135#ifdef CONFIG_COMPAT
 136int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn);
 137int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn);
 138#else
 139#define snd_ctl_register_ioctl_compat(fcn)
 140#define snd_ctl_unregister_ioctl_compat(fcn)
 141#endif
 142
 143int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type);
 144
 145static inline unsigned int snd_ctl_get_ioffnum(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
 146{
 147        unsigned int ioff = id->numid - kctl->id.numid;
 148        return array_index_nospec(ioff, kctl->count);
 149}
 150
 151static inline unsigned int snd_ctl_get_ioffidx(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
 152{
 153        unsigned int ioff = id->index - kctl->id.index;
 154        return array_index_nospec(ioff, kctl->count);
 155}
 156
 157static inline unsigned int snd_ctl_get_ioff(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
 158{
 159        if (id->numid) {
 160                return snd_ctl_get_ioffnum(kctl, id);
 161        } else {
 162                return snd_ctl_get_ioffidx(kctl, id);
 163        }
 164}
 165
 166static inline struct snd_ctl_elem_id *snd_ctl_build_ioff(struct snd_ctl_elem_id *dst_id,
 167                                                    struct snd_kcontrol *src_kctl,
 168                                                    unsigned int offset)
 169{
 170        *dst_id = src_kctl->id;
 171        dst_id->index += offset;
 172        dst_id->numid += offset;
 173        return dst_id;
 174}
 175
 176/*
 177 * Frequently used control callbacks/helpers
 178 */
 179int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
 180                              struct snd_ctl_elem_info *uinfo);
 181int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
 182                                struct snd_ctl_elem_info *uinfo);
 183int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
 184                      unsigned int items, const char *const names[]);
 185
 186/*
 187 * virtual master control
 188 */
 189struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 190                                                 const unsigned int *tlv);
 191int _snd_ctl_add_follower(struct snd_kcontrol *master,
 192                          struct snd_kcontrol *follower,
 193                          unsigned int flags);
 194/* optional flags for follower */
 195#define SND_CTL_FOLLOWER_NEED_UPDATE    (1 << 0)
 196
 197/**
 198 * snd_ctl_add_follower - Add a virtual follower control
 199 * @master: vmaster element
 200 * @follower: follower element to add
 201 *
 202 * Add a virtual follower control to the given master element created via
 203 * snd_ctl_create_virtual_master() beforehand.
 204 *
 205 * All followers must be the same type (returning the same information
 206 * via info callback).  The function doesn't check it, so it's your
 207 * responsibility.
 208 *
 209 * Also, some additional limitations:
 210 * at most two channels,
 211 * logarithmic volume control (dB level) thus no linear volume,
 212 * master can only attenuate the volume without gain
 213 *
 214 * Return: Zero if successful or a negative error code.
 215 */
 216static inline int
 217snd_ctl_add_follower(struct snd_kcontrol *master, struct snd_kcontrol *follower)
 218{
 219        return _snd_ctl_add_follower(master, follower, 0);
 220}
 221
 222/**
 223 * snd_ctl_add_follower_uncached - Add a virtual follower control
 224 * @master: vmaster element
 225 * @follower: follower element to add
 226 *
 227 * Add a virtual follower control to the given master.
 228 * Unlike snd_ctl_add_follower(), the element added via this function
 229 * is supposed to have volatile values, and get callback is called
 230 * at each time queried from the master.
 231 *
 232 * When the control peeks the hardware values directly and the value
 233 * can be changed by other means than the put callback of the element,
 234 * this function should be used to keep the value always up-to-date.
 235 *
 236 * Return: Zero if successful or a negative error code.
 237 */
 238static inline int
 239snd_ctl_add_follower_uncached(struct snd_kcontrol *master,
 240                              struct snd_kcontrol *follower)
 241{
 242        return _snd_ctl_add_follower(master, follower, SND_CTL_FOLLOWER_NEED_UPDATE);
 243}
 244
 245int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kctl,
 246                             void (*hook)(void *private_data, int),
 247                             void *private_data);
 248void snd_ctl_sync_vmaster(struct snd_kcontrol *kctl, bool hook_only);
 249#define snd_ctl_sync_vmaster_hook(kctl) snd_ctl_sync_vmaster(kctl, true)
 250int snd_ctl_apply_vmaster_followers(struct snd_kcontrol *kctl,
 251                                    int (*func)(struct snd_kcontrol *vfollower,
 252                                                struct snd_kcontrol *follower,
 253                                                void *arg),
 254                                    void *arg);
 255
 256/*
 257 * Helper functions for jack-detection controls
 258 */
 259struct snd_kcontrol *
 260snd_kctl_jack_new(const char *name, struct snd_card *card);
 261void snd_kctl_jack_report(struct snd_card *card,
 262                          struct snd_kcontrol *kctl, bool status);
 263
 264#endif  /* __SOUND_CONTROL_H */
 265