root/sound/firewire/motu/motu-pcm.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * motu-pcm.c - a part of driver for MOTU FireWire series
 *
 * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
 */

#include <sound/pcm_params.h>
#include "motu.h"

static int motu_rate_constraint(struct snd_pcm_hw_params *params,
                                struct snd_pcm_hw_rule *rule)
{
        struct snd_motu_packet_format *formats = rule->private;

        const struct snd_interval *c =
                hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
        struct snd_interval *r =
                hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
        struct snd_interval rates = {
                .min = UINT_MAX, .max = 0, .integer = 1
        };
        unsigned int i, pcm_channels, rate, mode;

        for (i = 0; i < ARRAY_SIZE(snd_motu_clock_rates); ++i) {
                rate = snd_motu_clock_rates[i];
                mode = i / 2;

                pcm_channels = formats->pcm_chunks[mode];
                if (!snd_interval_test(c, pcm_channels))
                        continue;

                rates.min = min(rates.min, rate);
                rates.max = max(rates.max, rate);
        }

        return snd_interval_refine(r, &rates);
}

static int motu_channels_constraint(struct snd_pcm_hw_params *params,
                                    struct snd_pcm_hw_rule *rule)
{
        struct snd_motu_packet_format *formats = rule->private;

        const struct snd_interval *r =
                hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
        struct snd_interval *c =
                hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
        struct snd_interval channels = {
                .min = UINT_MAX, .max = 0, .integer = 1
        };
        unsigned int i, pcm_channels, rate, mode;

        for (i = 0; i < ARRAY_SIZE(snd_motu_clock_rates); ++i) {
                rate = snd_motu_clock_rates[i];
                mode = i / 2;

                if (!snd_interval_test(r, rate))
                        continue;

                pcm_channels = formats->pcm_chunks[mode];
                channels.min = min(channels.min, pcm_channels);
                channels.max = max(channels.max, pcm_channels);
        }

        return snd_interval_refine(c, &channels);
}

static void limit_channels_and_rates(struct snd_motu *motu,
                                     struct snd_pcm_runtime *runtime,
                                     struct snd_motu_packet_format *formats)
{
        struct snd_pcm_hardware *hw = &runtime->hw;
        unsigned int i, pcm_channels, rate, mode;

        hw->channels_min = UINT_MAX;
        hw->channels_max = 0;

        for (i = 0; i < ARRAY_SIZE(snd_motu_clock_rates); ++i) {
                rate = snd_motu_clock_rates[i];
                mode = i / 2;

                pcm_channels = formats->pcm_chunks[mode];
                if (pcm_channels == 0)
                        continue;

                hw->rates |= snd_pcm_rate_to_rate_bit(rate);
                hw->channels_min = min(hw->channels_min, pcm_channels);
                hw->channels_max = max(hw->channels_max, pcm_channels);
        }

        snd_pcm_limit_hw_rates(runtime);
}

static int init_hw_info(struct snd_motu *motu,
                        struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_pcm_hardware *hw = &runtime->hw;
        struct amdtp_stream *stream;
        struct snd_motu_packet_format *formats;
        int err;

        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
                hw->formats = SNDRV_PCM_FMTBIT_S32;
                stream = &motu->tx_stream;
                formats = &motu->tx_packet_formats;
        } else {
                hw->formats = SNDRV_PCM_FMTBIT_S32;
                stream = &motu->rx_stream;
                formats = &motu->rx_packet_formats;
        }

        limit_channels_and_rates(motu, runtime, formats);

        err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                  motu_rate_constraint, formats,
                                  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
        if (err < 0)
                return err;
        err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
                                  motu_channels_constraint, formats,
                                  SNDRV_PCM_HW_PARAM_RATE, -1);
        if (err < 0)
                return err;

        return amdtp_motu_add_pcm_hw_constraints(stream, runtime);
}

static int pcm_open(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;
        struct amdtp_domain *d = &motu->domain;
        enum snd_motu_clock_source src;
        int err;

        err = snd_motu_stream_lock_try(motu);
        if (err < 0)
                return err;

        scoped_guard(mutex, &motu->mutex) {
                err = snd_motu_stream_cache_packet_formats(motu);
                if (err < 0)
                        goto err_locked;

                err = init_hw_info(motu, substream);
                if (err < 0)
                        goto err_locked;

                err = snd_motu_protocol_get_clock_source(motu, &src);
                if (err < 0)
                        goto err_locked;

                // When source of clock is not internal or any stream is reserved for
                // transmission of PCM frames, the available sampling rate is limited
                // at current one.
                if ((src != SND_MOTU_CLOCK_SOURCE_INTERNAL &&
                     src != SND_MOTU_CLOCK_SOURCE_SPH) ||
                    (motu->substreams_counter > 0 && d->events_per_period > 0)) {
                        unsigned int frames_per_period = d->events_per_period;
                        unsigned int frames_per_buffer = d->events_per_buffer;
                        unsigned int rate;

                        err = snd_motu_protocol_get_clock_rate(motu, &rate);
                        if (err < 0)
                                goto err_locked;

                        substream->runtime->hw.rate_min = rate;
                        substream->runtime->hw.rate_max = rate;

                        if (frames_per_period > 0) {
                                err = snd_pcm_hw_constraint_minmax(substream->runtime,
                                                                   SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
                                                                   frames_per_period, frames_per_period);
                                if (err < 0)
                                        goto err_locked;

                                err = snd_pcm_hw_constraint_minmax(substream->runtime,
                                                                   SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
                                                                   frames_per_buffer, frames_per_buffer);
                                if (err < 0)
                                        goto err_locked;
                        }
                }
        }

        snd_pcm_set_sync(substream);

        return 0;
err_locked:
        snd_motu_stream_lock_release(motu);
        return err;
}

static int pcm_close(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;

        snd_motu_stream_lock_release(motu);

        return 0;
}

static int pcm_hw_params(struct snd_pcm_substream *substream,
                         struct snd_pcm_hw_params *hw_params)
{
        struct snd_motu *motu = substream->private_data;
        int err = 0;

        if (substream->runtime->state == SNDRV_PCM_STATE_OPEN) {
                unsigned int rate = params_rate(hw_params);
                unsigned int frames_per_period = params_period_size(hw_params);
                unsigned int frames_per_buffer = params_buffer_size(hw_params);

                guard(mutex)(&motu->mutex);
                err = snd_motu_stream_reserve_duplex(motu, rate,
                                        frames_per_period, frames_per_buffer);
                if (err >= 0)
                        ++motu->substreams_counter;
        }

        return err;
}

static int pcm_hw_free(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;

        guard(mutex)(&motu->mutex);

        if (substream->runtime->state != SNDRV_PCM_STATE_OPEN)
                --motu->substreams_counter;

        snd_motu_stream_stop_duplex(motu);

        return 0;
}

static int capture_prepare(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;
        int err;

        scoped_guard(mutex, &motu->mutex) {
                err = snd_motu_stream_start_duplex(motu);
        }
        if (err >= 0)
                amdtp_stream_pcm_prepare(&motu->tx_stream);

        return 0;
}
static int playback_prepare(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;
        int err;

        scoped_guard(mutex, &motu->mutex) {
                err = snd_motu_stream_start_duplex(motu);
        }
        if (err >= 0)
                amdtp_stream_pcm_prepare(&motu->rx_stream);

        return err;
}

static int capture_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct snd_motu *motu = substream->private_data;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                amdtp_stream_pcm_trigger(&motu->tx_stream, substream);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                amdtp_stream_pcm_trigger(&motu->tx_stream, NULL);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}
static int playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct snd_motu *motu = substream->private_data;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                amdtp_stream_pcm_trigger(&motu->rx_stream, substream);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                amdtp_stream_pcm_trigger(&motu->rx_stream, NULL);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static snd_pcm_uframes_t capture_pointer(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;

        return amdtp_domain_stream_pcm_pointer(&motu->domain, &motu->tx_stream);
}
static snd_pcm_uframes_t playback_pointer(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;

        return amdtp_domain_stream_pcm_pointer(&motu->domain, &motu->rx_stream);
}

static int capture_ack(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;

        return amdtp_domain_stream_pcm_ack(&motu->domain, &motu->tx_stream);
}

static int playback_ack(struct snd_pcm_substream *substream)
{
        struct snd_motu *motu = substream->private_data;

        return amdtp_domain_stream_pcm_ack(&motu->domain, &motu->rx_stream);
}

int snd_motu_create_pcm_devices(struct snd_motu *motu)
{
        static const struct snd_pcm_ops capture_ops = {
                .open      = pcm_open,
                .close     = pcm_close,
                .hw_params = pcm_hw_params,
                .hw_free   = pcm_hw_free,
                .prepare   = capture_prepare,
                .trigger   = capture_trigger,
                .pointer   = capture_pointer,
                .ack       = capture_ack,
        };
        static const struct snd_pcm_ops playback_ops = {
                .open      = pcm_open,
                .close     = pcm_close,
                .hw_params = pcm_hw_params,
                .hw_free   = pcm_hw_free,
                .prepare   = playback_prepare,
                .trigger   = playback_trigger,
                .pointer   = playback_pointer,
                .ack       = playback_ack,
        };
        struct snd_pcm *pcm;
        int err;

        err = snd_pcm_new(motu->card, motu->card->driver, 0, 1, 1, &pcm);
        if (err < 0)
                return err;
        pcm->private_data = motu;
        pcm->nonatomic = true;
        strscpy(pcm->name, motu->card->shortname);

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);

        return 0;
}