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875becf8412c60ffae93c5f69e95a4d023f0e8ee
android_kernel_xiaomi_sm8450/sound/firewire/bebob/bebob_pcm.c
Takashi Sakamoto 875becf841 ALSA: firewire: process packets in 'struct snd_pcm_ops.ack' callback 
In recent commit for ALSA PCM core, some arrangement is done for
'struct snd_pcm_ops.ack' callback. This is called when appl_ptr is
explicitly moved in intermediate buffer for PCM frames, except for
some cases described later.

For drivers in ALSA firewire stack, usage of this callback has a merit to
reduce latency between time of PCM frame queueing and handling actual
packets in recent isochronous cycle, because no need to wait for software
IRQ context from isochronous context of OHCI 1394.

If this works well in a case that mapped page frame is used for the
intermediate buffer, user process should execute some commands for ioctl(2)
to tell the number of handled PCM frames in the intermediate buffer just
after handling them. Therefore, at present, with a combination of below
conditions, this doesn't work as expected and user process should wait for
the software IRQ context as usual:
 - when ALSA PCM core judges page frame mapping is available for status
   data (struct snd_pcm_mmap_status) and control data
   (struct snd_pcm_mmap_control).
 - user process handles PCM frames by loop just with 'snd_pcm_mmap_begin()'
   and 'snd_pcm_mmap_commit()'.
 - user process uses PCM hw plugin in alsa-lib to operate I/O without
   'sync_ptr_ioctl' option.

Unfortunately, major use case include these three conditions.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-06-07 07:53:32 +02:00

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/*
* bebob_pcm.c - a part of driver for BeBoB based devices
*
* Copyright (c) 2013-2014 Takashi Sakamoto
*
* Licensed under the terms of the GNU General Public License, version 2.
*/
#include "./bebob.h"
static int
hw_rule_rate(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
{
struct snd_bebob_stream_formation *formations = rule->private;
struct snd_interval *r =
hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
const struct snd_interval *c =
hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
struct snd_interval t = {
.min = UINT_MAX, .max = 0, .integer = 1
};
unsigned int i;
for (i = 0; i < SND_BEBOB_STRM_FMT_ENTRIES; i++) {
/* entry is invalid */
if (formations[i].pcm == 0)
continue;
if (!snd_interval_test(c, formations[i].pcm))
continue;
t.min = min(t.min, snd_bebob_rate_table[i]);
t.max = max(t.max, snd_bebob_rate_table[i]);
}
return snd_interval_refine(r, &t);
}
static int
hw_rule_channels(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
{
struct snd_bebob_stream_formation *formations = rule->private;
struct snd_interval *c =
hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
const struct snd_interval *r =
hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
struct snd_interval t = {
.min = UINT_MAX, .max = 0, .integer = 1
};
unsigned int i;
for (i = 0; i < SND_BEBOB_STRM_FMT_ENTRIES; i++) {
/* entry is invalid */
if (formations[i].pcm == 0)
continue;
if (!snd_interval_test(r, snd_bebob_rate_table[i]))
continue;
t.min = min(t.min, formations[i].pcm);
t.max = max(t.max, formations[i].pcm);
}
return snd_interval_refine(c, &t);
}
static void
limit_channels_and_rates(struct snd_pcm_hardware *hw,
struct snd_bebob_stream_formation *formations)
{
unsigned int i;
hw->channels_min = UINT_MAX;
hw->channels_max = 0;
hw->rate_min = UINT_MAX;
hw->rate_max = 0;
hw->rates = 0;
for (i = 0; i < SND_BEBOB_STRM_FMT_ENTRIES; i++) {
/* entry has no PCM channels */
if (formations[i].pcm == 0)
continue;
hw->channels_min = min(hw->channels_min, formations[i].pcm);
hw->channels_max = max(hw->channels_max, formations[i].pcm);
hw->rate_min = min(hw->rate_min, snd_bebob_rate_table[i]);
hw->rate_max = max(hw->rate_max, snd_bebob_rate_table[i]);
hw->rates |= snd_pcm_rate_to_rate_bit(snd_bebob_rate_table[i]);
}
}
static void
limit_period_and_buffer(struct snd_pcm_hardware *hw)
{
hw->periods_min = 2; /* SNDRV_PCM_INFO_BATCH */
hw->periods_max = UINT_MAX;
hw->period_bytes_min = 4 * hw->channels_max; /* bytes for a frame */
/* Just to prevent from allocating much pages. */
hw->period_bytes_max = hw->period_bytes_min * 2048;
hw->buffer_bytes_max = hw->period_bytes_max * hw->periods_min;
}
static int
pcm_init_hw_params(struct snd_bebob *bebob,
struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct amdtp_stream *s;
struct snd_bebob_stream_formation *formations;
int err;
runtime->hw.info = SNDRV_PCM_INFO_BATCH |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_JOINT_DUPLEX |
SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID;
if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
runtime->hw.formats = AM824_IN_PCM_FORMAT_BITS;
s = &bebob->tx_stream;
formations = bebob->tx_stream_formations;
} else {
runtime->hw.formats = AM824_OUT_PCM_FORMAT_BITS;
s = &bebob->rx_stream;
formations = bebob->rx_stream_formations;
}
limit_channels_and_rates(&runtime->hw, formations);
limit_period_and_buffer(&runtime->hw);
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
hw_rule_channels, formations,
SNDRV_PCM_HW_PARAM_RATE, -1);
if (err < 0)
goto end;
err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
hw_rule_rate, formations,
SNDRV_PCM_HW_PARAM_CHANNELS, -1);
if (err < 0)
goto end;
err = amdtp_am824_add_pcm_hw_constraints(s, runtime);
end:
return err;
}
static int
pcm_open(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
const struct snd_bebob_rate_spec *spec = bebob->spec->rate;
unsigned int sampling_rate;
enum snd_bebob_clock_type src;
int err;
err = snd_bebob_stream_lock_try(bebob);
if (err < 0)
goto end;
err = pcm_init_hw_params(bebob, substream);
if (err < 0)
goto err_locked;
err = snd_bebob_stream_get_clock_src(bebob, &src);
if (err < 0)
goto err_locked;
/*
* When source of clock is internal or any PCM stream are running,
* the available sampling rate is limited at current sampling rate.
*/
if (src == SND_BEBOB_CLOCK_TYPE_EXTERNAL ||
amdtp_stream_pcm_running(&bebob->tx_stream) ||
amdtp_stream_pcm_running(&bebob->rx_stream)) {
err = spec->get(bebob, &sampling_rate);
if (err < 0) {
dev_err(&bebob->unit->device,
"fail to get sampling rate: %d\n", err);
goto err_locked;
}
substream->runtime->hw.rate_min = sampling_rate;
substream->runtime->hw.rate_max = sampling_rate;
}
snd_pcm_set_sync(substream);
end:
return err;
err_locked:
snd_bebob_stream_lock_release(bebob);
return err;
}
static int
pcm_close(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
snd_bebob_stream_lock_release(bebob);
return 0;
}
static int
pcm_capture_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
struct snd_bebob *bebob = substream->private_data;
int err;
err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
params_buffer_bytes(hw_params));
if (err < 0)
return err;
if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
mutex_lock(&bebob->mutex);
bebob->substreams_counter++;
mutex_unlock(&bebob->mutex);
}
return 0;
}
static int
pcm_playback_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
struct snd_bebob *bebob = substream->private_data;
int err;
err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
params_buffer_bytes(hw_params));
if (err < 0)
return err;
if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
mutex_lock(&bebob->mutex);
bebob->substreams_counter++;
mutex_unlock(&bebob->mutex);
}
return 0;
}
static int
pcm_capture_hw_free(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN) {
mutex_lock(&bebob->mutex);
bebob->substreams_counter--;
mutex_unlock(&bebob->mutex);
}
snd_bebob_stream_stop_duplex(bebob);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
static int
pcm_playback_hw_free(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN) {
mutex_lock(&bebob->mutex);
bebob->substreams_counter--;
mutex_unlock(&bebob->mutex);
}
snd_bebob_stream_stop_duplex(bebob);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
static int
pcm_capture_prepare(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
struct snd_pcm_runtime *runtime = substream->runtime;
int err;
err = snd_bebob_stream_start_duplex(bebob, runtime->rate);
if (err >= 0)
amdtp_stream_pcm_prepare(&bebob->tx_stream);
return err;
}
static int
pcm_playback_prepare(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
struct snd_pcm_runtime *runtime = substream->runtime;
int err;
err = snd_bebob_stream_start_duplex(bebob, runtime->rate);
if (err >= 0)
amdtp_stream_pcm_prepare(&bebob->rx_stream);
return err;
}
static int
pcm_capture_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct snd_bebob *bebob = substream->private_data;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
amdtp_stream_pcm_trigger(&bebob->tx_stream, substream);
break;
case SNDRV_PCM_TRIGGER_STOP:
amdtp_stream_pcm_trigger(&bebob->tx_stream, NULL);
break;
default:
return -EINVAL;
}
return 0;
}
static int
pcm_playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct snd_bebob *bebob = substream->private_data;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
amdtp_stream_pcm_trigger(&bebob->rx_stream, substream);
break;
case SNDRV_PCM_TRIGGER_STOP:
amdtp_stream_pcm_trigger(&bebob->rx_stream, NULL);
break;
default:
return -EINVAL;
}
return 0;
}
static snd_pcm_uframes_t
pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
{
struct snd_bebob *bebob = sbstrm->private_data;
return amdtp_stream_pcm_pointer(&bebob->tx_stream);
}
static snd_pcm_uframes_t
pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
{
struct snd_bebob *bebob = sbstrm->private_data;
return amdtp_stream_pcm_pointer(&bebob->rx_stream);
}
static int pcm_capture_ack(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
return amdtp_stream_pcm_ack(&bebob->tx_stream);
}
static int pcm_playback_ack(struct snd_pcm_substream *substream)
{
struct snd_bebob *bebob = substream->private_data;
return amdtp_stream_pcm_ack(&bebob->rx_stream);
}
int snd_bebob_create_pcm_devices(struct snd_bebob *bebob)
{
static const struct snd_pcm_ops capture_ops = {
.open = pcm_open,
.close = pcm_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = pcm_capture_hw_params,
.hw_free = pcm_capture_hw_free,
.prepare = pcm_capture_prepare,
.trigger = pcm_capture_trigger,
.pointer = pcm_capture_pointer,
.ack = pcm_capture_ack,
.page = snd_pcm_lib_get_vmalloc_page,
};
static const struct snd_pcm_ops playback_ops = {
.open = pcm_open,
.close = pcm_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = pcm_playback_hw_params,
.hw_free = pcm_playback_hw_free,
.prepare = pcm_playback_prepare,
.trigger = pcm_playback_trigger,
.pointer = pcm_playback_pointer,
.ack = pcm_playback_ack,
.page = snd_pcm_lib_get_vmalloc_page,
.mmap = snd_pcm_lib_mmap_vmalloc,
};
struct snd_pcm *pcm;
int err;
err = snd_pcm_new(bebob->card, bebob->card->driver, 0, 1, 1, &pcm);
if (err < 0)
goto end;
pcm->private_data = bebob;
snprintf(pcm->name, sizeof(pcm->name),
"%s PCM", bebob->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);
end:
return err;
}
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