modules/usbaudio/alsa_device_profile.c

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "alsa_device_profile"
/*#define LOG_NDEBUG 0*/
/*#define LOG_PCM_PARAMS 0*/

#include <errno.h>
#include <inttypes.h>
#include <stdint.h>
#include <stdlib.h>

#include <log/log.h>

#include "alsa_device_profile.h"
#include "audio_format.h"
#include "audio_logging.h"

#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))

/*TODO - Evaluate if this value should/can be retrieved from a device-specific property */
#define BUFF_DURATION_MS   5

#define DEFAULT_PERIOD_SIZE 1024

static const char * const format_string_map[] = {
    "AUDIO_FORMAT_PCM_16_BIT",      /* "PCM_FORMAT_S16_LE", */
    "AUDIO_FORMAT_PCM_32_BIT",      /* "PCM_FORMAT_S32_LE", */
    "AUDIO_FORMAT_PCM_8_BIT",       /* "PCM_FORMAT_S8", */
    "AUDIO_FORMAT_PCM_8_24_BIT",    /* "PCM_FORMAT_S24_LE", */
    "AUDIO_FORMAT_PCM_24_BIT_PACKED"/* "PCM_FORMAT_S24_3LE" */
};

static const unsigned const format_byte_size_map[] = {
    2, /* PCM_FORMAT_S16_LE */
    4, /* PCM_FORMAT_S32_LE */
    1, /* PCM_FORMAT_S8 */
    4, /* PCM_FORMAT_S24_LE */
    3, /* PCM_FORMAT_S24_3LE */
};

extern int8_t const pcm_format_value_map[50];

/* sort these highest -> lowest (to default to best quality) */
static const unsigned std_sample_rates[] =
    {48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000};

static void profile_reset(alsa_device_profile* profile)
{
    profile->card = profile->device = -1;

    /* Fill the attribute arrays with invalid values */
    size_t index;
    for (index = 0; index < ARRAY_SIZE(profile->formats); index++) {
        profile->formats[index] = PCM_FORMAT_INVALID;
    }

    for (index = 0; index < ARRAY_SIZE(profile->sample_rates); index++) {
        profile->sample_rates[index] = 0;
    }

    for (index = 0; index < ARRAY_SIZE(profile->channel_counts); index++) {
        profile->channel_counts[index] = 0;
    }

    profile->min_period_size = profile->max_period_size = 0;
    profile->min_channel_count = profile->max_channel_count = DEFAULT_CHANNEL_COUNT;

    profile->is_valid = false;
}

void profile_init(alsa_device_profile* profile, int direction)
{
    profile->direction = direction;
    profile_reset(profile);
}

bool profile_is_initialized(alsa_device_profile* profile)
{
    return profile->card >= 0 && profile->device >= 0;
}

bool profile_is_valid(alsa_device_profile* profile) {
    return profile->is_valid;
}

bool profile_is_cached_for(alsa_device_profile* profile, int card, int device) {
    return card == profile->card && device == profile->device;
}

void profile_decache(alsa_device_profile* profile) {
    profile_reset(profile);
}

/*
 * Returns the supplied value rounded up to the next even multiple of 16
 */
static unsigned int round_to_16_mult(unsigned int size)
{
    return (size + 15) & ~15;   // 0xFFFFFFF0;
}

/*
 * Returns the system defined minimum period size based on the supplied sample rate.
 */
unsigned profile_calc_min_period_size(alsa_device_profile* profile, unsigned sample_rate)
{
    ALOGV("profile_calc_min_period_size(%p, rate:%d)", profile, sample_rate);
    if (profile == NULL) {
        return DEFAULT_PERIOD_SIZE;
    } else {
        unsigned num_sample_frames = (sample_rate * BUFF_DURATION_MS) / 1000;
        if (num_sample_frames < profile->min_period_size) {
            num_sample_frames = profile->min_period_size;
        }
        return round_to_16_mult(num_sample_frames) * 2;
    }
}

unsigned int profile_get_period_size(alsa_device_profile* profile, unsigned sample_rate)
{
    // return profile->default_config.period_size;
    unsigned int period_size = profile_calc_min_period_size(profile, sample_rate);
    ALOGV("profile_get_period_size(rate:%d) = %d", sample_rate, period_size);
    return period_size;
}

/*
 * Sample Rate
 */
unsigned profile_get_default_sample_rate(alsa_device_profile* profile)
{
    /*
     * TODO this won't be right in general. we should store a preferred rate as we are scanning.
     * But right now it will return the highest rate, which may be correct.
     */
    return profile_is_valid(profile) ? profile->sample_rates[0] : DEFAULT_SAMPLE_RATE;
}

bool profile_is_sample_rate_valid(alsa_device_profile* profile, unsigned rate)
{
    if (profile_is_valid(profile)) {
        size_t index;
        for (index = 0; profile->sample_rates[index] != 0; index++) {
            if (profile->sample_rates[index] == rate) {
                return true;
            }
        }

        return false;
    } else {
        return rate == DEFAULT_SAMPLE_RATE;
    }
}

/*
 * Format
 */
enum pcm_format profile_get_default_format(alsa_device_profile* profile)
{
    /*
     * TODO this won't be right in general. we should store a preferred format as we are scanning.
     */
    return profile_is_valid(profile) ? profile->formats[0] : DEFAULT_SAMPLE_FORMAT;
}

bool profile_is_format_valid(alsa_device_profile* profile, enum pcm_format fmt) {
    if (profile_is_valid(profile)) {
        size_t index;
        for (index = 0; profile->formats[index] != PCM_FORMAT_INVALID; index++) {
            if (profile->formats[index] == fmt) {
                return true;
            }
        }

        return false;
    } else {
        return fmt == DEFAULT_SAMPLE_FORMAT;
    }
}

/*
 * Channels
 */
unsigned profile_get_default_channel_count(alsa_device_profile* profile)
{
    return profile_is_valid(profile) ? profile->channel_counts[0] : DEFAULT_CHANNEL_COUNT;
}

bool profile_is_channel_count_valid(alsa_device_profile* profile, unsigned count)
{
    if (profile_is_initialized(profile)) {
        return count >= profile->min_channel_count && count <= profile->max_channel_count;
    } else {
        return count == DEFAULT_CHANNEL_COUNT;
    }
}

static bool profile_test_sample_rate(alsa_device_profile* profile, unsigned rate)
{
    struct pcm_config config = profile->default_config;
    config.rate = rate;

    bool works = false; /* let's be pessimistic */
    struct pcm * pcm = pcm_open(profile->card, profile->device,
                                profile->direction, &config);

    if (pcm != NULL) {
        works = pcm_is_ready(pcm);
        pcm_close(pcm);
    }

    return works;
}

static unsigned profile_enum_sample_rates(alsa_device_profile* profile, unsigned min, unsigned max)
{
    unsigned num_entries = 0;
    unsigned index;

    for (index = 0; index < ARRAY_SIZE(std_sample_rates) &&
                    num_entries < ARRAY_SIZE(profile->sample_rates) - 1;
         index++) {
        if (std_sample_rates[index] >= min && std_sample_rates[index] <= max
                && profile_test_sample_rate(profile, std_sample_rates[index])) {
            profile->sample_rates[num_entries++] = std_sample_rates[index];
        }
    }

    return num_entries; /* return # of supported rates */
}

static unsigned profile_enum_sample_formats(alsa_device_profile* profile, struct pcm_mask * mask)
{
    const int num_slots = ARRAY_SIZE(mask->bits);
    const int bits_per_slot = sizeof(mask->bits[0]) * 8;

    const int table_size = ARRAY_SIZE(pcm_format_value_map);

    int slot_index, bit_index, table_index;
    table_index = 0;
    int num_written = 0;
    for (slot_index = 0; slot_index < num_slots && table_index < table_size;
            slot_index++) {
        unsigned bit_mask = 1;
        for (bit_index = 0;
                bit_index < bits_per_slot && table_index < table_size;
                bit_index++) {
            if ((mask->bits[slot_index] & bit_mask) != 0) {
                enum pcm_format format = pcm_format_value_map[table_index];
                /* Never return invalid (unrecognized) or 8-bit */
                if (format != PCM_FORMAT_INVALID && format != PCM_FORMAT_S8) {
                    profile->formats[num_written++] = format;
                    if (num_written == ARRAY_SIZE(profile->formats) - 1) {
                        /* leave at least one PCM_FORMAT_INVALID at the end */
                        return num_written;
                    }
                }
            }
            bit_mask <<= 1;
            table_index++;
        }
    }

    return num_written;
}

static unsigned profile_enum_channel_counts(alsa_device_profile* profile, unsigned min,
        unsigned max)
{
    static const unsigned std_channel_counts[] = {8, 4, 2, 1};

    unsigned num_counts = 0;
    unsigned index;
    /* TODO write a profile_test_channel_count() */
    /* Ensure there is at least one invalid channel count to terminate the channel counts array */
    for (index = 0; index < ARRAY_SIZE(std_channel_counts) &&
                    num_counts < ARRAY_SIZE(profile->channel_counts) - 1;
         index++) {
        /* TODO Do we want a channel counts test? */
        if (std_channel_counts[index] >= min && std_channel_counts[index] <= max /* &&
            profile_test_channel_count(profile, channel_counts[index])*/) {
            profile->channel_counts[num_counts++] = std_channel_counts[index];
        }
    }

    return num_counts; /* return # of supported counts */
}

/*
 * Reads and decodes configuration info from the specified ALSA card/device.
 */
static int read_alsa_device_config(alsa_device_profile * profile, struct pcm_config * config)
{
    ALOGV("usb:audio_hw - read_alsa_device_config(c:%d d:%d t:0x%X)",
          profile->card, profile->device, profile->direction);

    if (profile->card < 0 || profile->device < 0) {
        return -EINVAL;
    }

    struct pcm_params * alsa_hw_params =
        pcm_params_get(profile->card, profile->device, profile->direction);
    if (alsa_hw_params == NULL) {
        return -EINVAL;
    }

    profile->min_period_size = pcm_params_get_min(alsa_hw_params, PCM_PARAM_PERIOD_SIZE);
    profile->max_period_size = pcm_params_get_max(alsa_hw_params, PCM_PARAM_PERIOD_SIZE);

    profile->min_channel_count = pcm_params_get_min(alsa_hw_params, PCM_PARAM_CHANNELS);
    profile->max_channel_count = pcm_params_get_max(alsa_hw_params, PCM_PARAM_CHANNELS);

    int ret = 0;

    /*
     * This Logging will be useful when testing new USB devices.
     */
#ifdef LOG_PCM_PARAMS
    log_pcm_params(alsa_hw_params);
#endif

    config->channels = pcm_params_get_min(alsa_hw_params, PCM_PARAM_CHANNELS);
    config->rate = pcm_params_get_min(alsa_hw_params, PCM_PARAM_RATE);
    config->period_size = profile_calc_min_period_size(profile, config->rate);
    config->period_count = pcm_params_get_min(alsa_hw_params, PCM_PARAM_PERIODS);
    config->format = get_pcm_format_for_mask(pcm_params_get_mask(alsa_hw_params, PCM_PARAM_FORMAT));
#ifdef LOG_PCM_PARAMS
    log_pcm_config(config, "read_alsa_device_config");
#endif
    if (config->format == PCM_FORMAT_INVALID) {
        ret = -EINVAL;
    }

    pcm_params_free(alsa_hw_params);

    return ret;
}

bool profile_read_device_info(alsa_device_profile* profile)
{
    if (!profile_is_initialized(profile)) {
        return false;
    }

    /* let's get some defaults */
    read_alsa_device_config(profile, &profile->default_config);
    ALOGV("default_config chans:%d rate:%d format:%d count:%d size:%d",
          profile->default_config.channels, profile->default_config.rate,
          profile->default_config.format, profile->default_config.period_count,
          profile->default_config.period_size);

    struct pcm_params * alsa_hw_params = pcm_params_get(profile->card,
                                                        profile->device,
                                                        profile->direction);
    if (alsa_hw_params == NULL) {
        return false;
    }

    /* Formats */
    struct pcm_mask * format_mask = pcm_params_get_mask(alsa_hw_params, PCM_PARAM_FORMAT);
    profile_enum_sample_formats(profile, format_mask);

    /* Channels */
    profile_enum_channel_counts(
            profile, pcm_params_get_min(alsa_hw_params, PCM_PARAM_CHANNELS),
            pcm_params_get_max(alsa_hw_params, PCM_PARAM_CHANNELS));

    /* Sample Rates */
    profile_enum_sample_rates(
            profile, pcm_params_get_min(alsa_hw_params, PCM_PARAM_RATE),
            pcm_params_get_max(alsa_hw_params, PCM_PARAM_RATE));

    profile->is_valid = true;

    return true;
}

char * profile_get_sample_rate_strs(alsa_device_profile* profile)
{
    char buffer[128];
    buffer[0] = '\0';
    int buffSize = ARRAY_SIZE(buffer);

    char numBuffer[32];

    int numEntries = 0;
    unsigned index;
    for (index = 0; profile->sample_rates[index] != 0; index++) {
        if (numEntries++ != 0) {
            strncat(buffer, "|", buffSize);
        }
        snprintf(numBuffer, sizeof(numBuffer), "%u", profile->sample_rates[index]);
        strncat(buffer, numBuffer, buffSize);
    }

    return strdup(buffer);
}

char * profile_get_format_strs(alsa_device_profile* profile)
{
    /* TODO remove this hack when we have support for input in non PCM16 formats */
    if (profile->direction == PCM_IN) {
        return strdup("AUDIO_FORMAT_PCM_16_BIT");
    }

    char buffer[128];
    buffer[0] = '\0';
    int buffSize = ARRAY_SIZE(buffer);

    int numEntries = 0;
    unsigned index = 0;
    for (index = 0; profile->formats[index] != PCM_FORMAT_INVALID; index++) {
        if (numEntries++ != 0) {
            strncat(buffer, "|", buffSize);
        }
        strncat(buffer, format_string_map[profile->formats[index]], buffSize);
    }

    return strdup(buffer);
}

char * profile_get_channel_count_strs(alsa_device_profile* profile)
{
    static const char * const out_chans_strs[] = {
        /* 0 */"AUDIO_CHANNEL_NONE", /* will never be taken as this is a terminator */
        /* 1 */"AUDIO_CHANNEL_OUT_MONO",
        /* 2 */"AUDIO_CHANNEL_OUT_STEREO",
        /* 3 */ /* "AUDIO_CHANNEL_OUT_STEREO|AUDIO_CHANNEL_OUT_FRONT_CENTER" */ NULL,
        /* 4 */"AUDIO_CHANNEL_OUT_QUAD",
        /* 5 */ /* "AUDIO_CHANNEL_OUT_QUAD|AUDIO_CHANNEL_OUT_FRONT_CENTER" */ NULL,
        /* 6 */"AUDIO_CHANNEL_OUT_5POINT1",
        /* 7 */ /* "AUDIO_CHANNEL_OUT_5POINT1|AUDIO_CHANNEL_OUT_BACK_CENTER" */ NULL,
        /* 8 */"AUDIO_CHANNEL_OUT_7POINT1",
        /* channel counts greater than this not considered */
    };

    static const char * const in_chans_strs[] = {
        /* 0 */"AUDIO_CHANNEL_NONE", /* will never be taken as this is a terminator */
        /* 1 */"AUDIO_CHANNEL_IN_MONO",
        /* 2 */"AUDIO_CHANNEL_IN_STEREO",
        /* channel counts greater than this not considered */
    };

    const bool isOutProfile = profile->direction == PCM_OUT;

    const char * const * const names_array = isOutProfile ? out_chans_strs : in_chans_strs;
    const size_t names_size = isOutProfile ? ARRAY_SIZE(out_chans_strs)
            : ARRAY_SIZE(in_chans_strs);

    char buffer[256]; /* caution, may need to be expanded */
    buffer[0] = '\0';
    const int buffer_size = ARRAY_SIZE(buffer);
    int num_entries = 0;
    /* We currently support MONO and STEREO, and always report STEREO but some (many)
     * USB Audio Devices may only announce support for MONO (a headset mic for example), or
     * The total number of output channels. SO, if the device itself doesn't explicitly
     * support STEREO, append to the channel config strings we are generating.
     */
    bool stereo_present = false;
    unsigned index;
    unsigned channel_count;

    for (index = 0; (channel_count = profile->channel_counts[index]) != 0; index++) {
        stereo_present = stereo_present || channel_count == 2;
        if (channel_count < names_size && names_array[channel_count] != NULL) {
            if (num_entries++ != 0) {
                strncat(buffer, "|", buffer_size);
            }
            strncat(buffer, names_array[channel_count], buffer_size);
        }
    }

    /* emulated modes:
     * always expose stereo as we can emulate it for PCM_OUT
     */
    if (!stereo_present) {
        if (num_entries++ != 0) {
            strncat(buffer, "|", buffer_size);
        }
        strncat(buffer, names_array[2], buffer_size); /* stereo */
    }

    return strdup(buffer);
}