Commit 2d3391ec authored by Takashi Iwai's avatar Takashi Iwai
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ALSA: PCM: channel mapping API implementation



This patch implements the basic data types for the standard channel
mapping API handling.

- The definitions of the channel positions and the new TLV types are
  added in sound/asound.h and sound/tlv.h, so that they can be
  referred from user-space.

- Introduced a new helper function snd_pcm_add_chmap_ctls() to create
  control elements representing the channel maps for each PCM
  (sub)stream.

- Some standard pre-defined channel maps are provided for
  convenience.
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent a8d372f1
......@@ -472,6 +472,36 @@ enum {
SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC,
};
/* channel positions */
enum {
SNDRV_CHMAP_UNKNOWN = 0,
SNDRV_CHMAP_FL, /* front left */
SNDRV_CHMAP_FC, /* front center */
SNDRV_CHMAP_FR, /* front right */
SNDRV_CHMAP_FLC, /* front left center */
SNDRV_CHMAP_FRC, /* front right center */
SNDRV_CHMAP_RL, /* rear left */
SNDRV_CHMAP_RC, /* rear center */
SNDRV_CHMAP_RR, /* rear right */
SNDRV_CHMAP_RLC, /* rear left center */
SNDRV_CHMAP_RRC, /* rear right center */
SNDRV_CHMAP_SL, /* side left */
SNDRV_CHMAP_SR, /* side right */
SNDRV_CHMAP_LFE, /* LFE */
SNDRV_CHMAP_FLW, /* front left wide */
SNDRV_CHMAP_FRW, /* front right wide */
SNDRV_CHMAP_FLH, /* front left high */
SNDRV_CHMAP_FCH, /* front center high */
SNDRV_CHMAP_FRH, /* front right high */
SNDRV_CHMAP_TC, /* top center */
SNDRV_CHMAP_NA, /* N/A, silent */
SNDRV_CHMAP_LAST = SNDRV_CHMAP_NA,
};
#define SNDRV_CHMAP_POSITION_MASK 0xffff
#define SNDRV_CHMAP_PHASE_INVERSE (0x01 << 16)
#define SNDRV_CHMAP_DRIVER_SPEC (0x02 << 16)
#define SNDRV_PCM_IOCTL_PVERSION _IOR('A', 0x00, int)
#define SNDRV_PCM_IOCTL_INFO _IOR('A', 0x01, struct snd_pcm_info)
#define SNDRV_PCM_IOCTL_TSTAMP _IOW('A', 0x02, int)
......
......@@ -437,6 +437,7 @@ struct snd_pcm_str {
struct snd_info_entry *proc_xrun_debug_entry;
#endif
#endif
struct snd_kcontrol *chmap_kctl; /* channel-mapping controls */
};
struct snd_pcm {
......@@ -1086,4 +1087,51 @@ static inline const char *snd_pcm_stream_str(struct snd_pcm_substream *substream
return "Capture";
}
/*
* PCM channel-mapping control API
*/
/* array element of channel maps */
struct snd_pcm_chmap_elem {
unsigned char channels;
unsigned char map[15];
};
/* channel map information; retrieved via snd_kcontrol_chip() */
struct snd_pcm_chmap {
struct snd_pcm *pcm; /* assigned PCM instance */
int stream; /* PLAYBACK or CAPTURE */
struct snd_kcontrol *kctl;
const struct snd_pcm_chmap_elem *chmap;
unsigned int max_channels;
unsigned int channel_mask; /* optional: active channels bitmask */
void *private_data; /* optional: private data pointer */
};
/* get the PCM substream assigned to the given chmap info */
static inline struct snd_pcm_substream *
snd_pcm_chmap_substream(struct snd_pcm_chmap *info, unsigned int idx)
{
struct snd_pcm_substream *s;
for (s = info->pcm->streams[info->stream].substream; s; s = s->next)
if (s->number == idx)
return s;
return NULL;
}
/* ALSA-standard channel maps (RL/RR prior to C/LFE) */
extern const struct snd_pcm_chmap_elem snd_pcm_std_chmaps[];
/* Other world's standard channel maps (C/LFE prior to RL/RR) */
extern const struct snd_pcm_chmap_elem snd_pcm_alt_chmaps[];
/* bit masks to be passed to snd_pcm_chmap.channel_mask field */
#define SND_PCM_CHMAP_MASK_24 ((1U << 2) | (1U << 4))
#define SND_PCM_CHMAP_MASK_246 (SND_PCM_CHMAP_MASK_24 | (1U << 6))
#define SND_PCM_CHMAP_MASK_2468 (SND_PCM_CHMAP_MASK_246 | (1U << 8))
int snd_pcm_add_chmap_ctls(struct snd_pcm *pcm, int stream,
const struct snd_pcm_chmap_elem *chmap,
int max_channels,
unsigned long private_value,
struct snd_pcm_chmap **info_ret);
#endif /* __SOUND_PCM_H */
......@@ -86,4 +86,12 @@
#define TLV_DB_GAIN_MUTE -9999999
/*
* channel-mapping TLV items
* TLV length must match with num_channels
*/
#define SNDRV_CTL_TLVT_CHMAP_FIXED 0x101 /* fixed channel position */
#define SNDRV_CTL_TLVT_CHMAP_VAR 0x102 /* channels freely swappable */
#define SNDRV_CTL_TLVT_CHMAP_PAIRED 0x103 /* pair-wise swappable */
#endif /* __SOUND_TLV_H */
......@@ -1105,6 +1105,10 @@ static int snd_pcm_dev_disconnect(struct snd_device *device)
break;
}
snd_unregister_device(devtype, pcm->card, pcm->device);
if (pcm->streams[cidx].chmap_kctl) {
snd_ctl_remove(pcm->card, pcm->streams[cidx].chmap_kctl);
pcm->streams[cidx].chmap_kctl = NULL;
}
}
unlock:
mutex_unlock(&register_mutex);
......
......@@ -26,6 +26,7 @@
#include <linux/export.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/tlv.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
......@@ -2302,3 +2303,217 @@ snd_pcm_sframes_t snd_pcm_lib_readv(struct snd_pcm_substream *substream,
}
EXPORT_SYMBOL(snd_pcm_lib_readv);
/*
* standard channel mapping helpers
*/
/* default channel maps for multi-channel playbacks, up to 8 channels */
const struct snd_pcm_chmap_elem snd_pcm_std_chmaps[] = {
{ .channels = 1,
.map = { SNDRV_CHMAP_FC } },
{ .channels = 2,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR } },
{ .channels = 4,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
{ .channels = 6,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
SNDRV_CHMAP_RL, SNDRV_CHMAP_RR,
SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE } },
{ .channels = 8,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
SNDRV_CHMAP_RL, SNDRV_CHMAP_RR,
SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE,
SNDRV_CHMAP_SL, SNDRV_CHMAP_SR } },
{ }
};
EXPORT_SYMBOL_GPL(snd_pcm_std_chmaps);
/* alternative channel maps with CLFE <-> surround swapped for 6/8 channels */
const struct snd_pcm_chmap_elem snd_pcm_alt_chmaps[] = {
{ .channels = 1,
.map = { SNDRV_CHMAP_FC } },
{ .channels = 2,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR } },
{ .channels = 4,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
{ .channels = 6,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE,
SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
{ .channels = 8,
.map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE,
SNDRV_CHMAP_RL, SNDRV_CHMAP_RR,
SNDRV_CHMAP_SL, SNDRV_CHMAP_SR } },
{ }
};
EXPORT_SYMBOL_GPL(snd_pcm_alt_chmaps);
static bool valid_chmap_channels(const struct snd_pcm_chmap *info, int ch)
{
if (ch > info->max_channels)
return false;
return !info->channel_mask || (info->channel_mask & (1U << ch));
}
static int pcm_chmap_ctl_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
uinfo->count = 0;
uinfo->count = info->max_channels;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = SNDRV_CHMAP_LAST;
return 0;
}
/* get callback for channel map ctl element
* stores the channel position firstly matching with the current channels
*/
static int pcm_chmap_ctl_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
struct snd_pcm_substream *substream;
const struct snd_pcm_chmap_elem *map;
if (snd_BUG_ON(!info->chmap))
return -EINVAL;
substream = snd_pcm_chmap_substream(info, idx);
if (!substream)
return -ENODEV;
memset(ucontrol->value.integer.value, 0,
sizeof(ucontrol->value.integer.value));
if (!substream->runtime)
return 0; /* no channels set */
for (map = info->chmap; map->channels; map++) {
int i;
if (map->channels == substream->runtime->channels &&
valid_chmap_channels(info, map->channels)) {
for (i = 0; i < map->channels; i++)
ucontrol->value.integer.value[i] = map->map[i];
return 0;
}
}
return -EINVAL;
}
/* tlv callback for channel map ctl element
* expands the pre-defined channel maps in a form of TLV
*/
static int pcm_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
unsigned int size, unsigned int __user *tlv)
{
struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
const struct snd_pcm_chmap_elem *map;
unsigned int __user *dst;
int c, count = 0;
if (snd_BUG_ON(!info->chmap))
return -EINVAL;
if (size < 8)
return -ENOMEM;
if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
return -EFAULT;
size -= 8;
dst = tlv + 2;
for (map = info->chmap; map->channels; map++) {
int chs_bytes = map->channels * 4;
if (!valid_chmap_channels(info, map->channels))
continue;
if (size < 8)
return -ENOMEM;
if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
put_user(chs_bytes, dst + 1))
return -EFAULT;
dst += 2;
size -= 8;
count += 8;
if (size < chs_bytes)
return -ENOMEM;
size -= chs_bytes;
count += chs_bytes;
for (c = 0; c < map->channels; c++) {
if (put_user(map->map[c], dst))
return -EFAULT;
dst++;
}
}
if (put_user(count, tlv + 1))
return -EFAULT;
return 0;
}
static void pcm_chmap_ctl_private_free(struct snd_kcontrol *kcontrol)
{
struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
info->pcm->streams[info->stream].chmap_kctl = NULL;
kfree(info);
}
/**
* snd_pcm_add_chmap_ctls - create channel-mapping control elements
* @pcm: the assigned PCM instance
* @stream: stream direction
* @chmap: channel map elements (for query)
* @max_channels: the max number of channels for the stream
* @private_value: the value passed to each kcontrol's private_value field
* @info_ret: store struct snd_pcm_chmap instance if non-NULL
*
* Create channel-mapping control elements assigned to the given PCM stream(s).
* Returns zero if succeed, or a negative error value.
*/
int snd_pcm_add_chmap_ctls(struct snd_pcm *pcm, int stream,
const struct snd_pcm_chmap_elem *chmap,
int max_channels,
unsigned long private_value,
struct snd_pcm_chmap **info_ret)
{
struct snd_pcm_chmap *info;
struct snd_kcontrol_new knew = {
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.access = SNDRV_CTL_ELEM_ACCESS_READ |
SNDRV_CTL_ELEM_ACCESS_VOLATILE | /* no notification */
SNDRV_CTL_ELEM_ACCESS_TLV_READ |
SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK,
.info = pcm_chmap_ctl_info,
.get = pcm_chmap_ctl_get,
.tlv.c = pcm_chmap_ctl_tlv,
};
int err;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
return -ENOMEM;
info->pcm = pcm;
info->stream = stream;
info->chmap = chmap;
info->max_channels = max_channels;
if (stream == SNDRV_PCM_STREAM_PLAYBACK)
knew.name = "Playback Channel Map";
else
knew.name = "Capture Channel Map";
knew.device = pcm->device;
knew.count = pcm->streams[stream].substream_count;
knew.private_value = private_value;
info->kctl = snd_ctl_new1(&knew, info);
if (!info->kctl) {
kfree(info);
return -ENOMEM;
}
info->kctl->private_free = pcm_chmap_ctl_private_free;
err = snd_ctl_add(pcm->card, info->kctl);
if (err < 0)
return err;
pcm->streams[stream].chmap_kctl = info->kctl;
if (info_ret)
*info_ret = info;
return 0;
}
EXPORT_SYMBOL_GPL(snd_pcm_add_chmap_ctls);
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