cras/src/server/cras_alsa_ucm.c

/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include <alsa/asoundlib.h>
#include <alsa/use-case.h>
#include <ctype.h>
#include <string.h>
#include <syslog.h>

#include "cras_alsa_ucm.h"
#include "cras_util.h"
#include "utlist.h"

static const char jack_control_var[] = "JackControl";
static const char jack_dev_var[] = "JackDev";
static const char jack_switch_var[] = "JackSwitch";
static const char edid_var[] = "EDIDFile";
static const char cap_var[] = "CaptureControl";
static const char override_type_name_var[] = "OverrideNodeType";
static const char dsp_name_var[] = "DspName";
static const char playback_mixer_elem_var[] = "PlaybackMixerElem";
static const char capture_mixer_elem_var[] = "CaptureMixerElem";
static const char swap_mode_suffix[] = "Swap Mode";
static const char min_buffer_level_var[] = "MinBufferLevel";
static const char dma_period_var[] = "DmaPeriodMicrosecs";
static const char disable_software_volume[] = "DisableSoftwareVolume";
static const char playback_device_name_var[] = "PlaybackPCM";
static const char playback_device_rate_var[] = "PlaybackRate";
static const char playback_channels_var[] = "PlaybackChannels";
static const char capture_device_name_var[] = "CapturePCM";
static const char capture_device_rate_var[] = "CaptureRate";
static const char capture_channel_map_var[] = "CaptureChannelMap";
static const char capture_channels_var[] = "CaptureChannels";
static const char coupled_mixers[] = "CoupledMixers";
static const char dependent_device_name_var[] = "DependentPCM";
static const char preempt_hotword_var[] = "PreemptHotword";
static const char echo_reference_dev_name_var[] = "EchoReferenceDev";

/*
 * Set this value in a SectionDevice to specify the intrinsic sensitivity in
 * 0.01 dBFS/Pa. It currently only supports input devices. You should get the
 * value by recording samples without either hardware or software gain. We are
 * still working on building a standard process for measuring it. The value you
 * see now in our UCM is just estimated value. If it is set, CRAS will enable
 * software gain and use the value as a reference for calculating the
 * appropriate software gain to apply to the device to meet our target volume.
 */
static const char intrinsic_sensitivity_var[] = "IntrinsicSensitivity";

/*
 * Set this value in a SectionDevice to specify the default node gain in
 * 0.01 dB.
 */
static const char default_node_gain[] = "DefaultNodeGain";
static const char hotword_model_prefix[] = "Hotword Model";
static const char fully_specified_ucm_var[] = "FullySpecifiedUCM";
static const char main_volume_names[] = "MainVolumeNames";

/* Use case verbs corresponding to CRAS_STREAM_TYPE. */
static const char *use_case_verbs[] = {
	"HiFi",	  "Multimedia", "Voice Call",
	"Speech", "Pro Audio",	"Accessibility",
};

/* Represents a list of section names found in UCM. */
struct section_name {
	const char *name;
	struct section_name *prev, *next;
};

struct cras_use_case_mgr {
	snd_use_case_mgr_t *mgr;
	const char *name;
	unsigned int avail_use_cases;
	enum CRAS_STREAM_TYPE use_case;
};

static inline const char *uc_verb(struct cras_use_case_mgr *mgr)
{
	return use_case_verbs[mgr->use_case];
}

static int device_enabled(struct cras_use_case_mgr *mgr, const char *dev)
{
	const char **list;
	unsigned int i;
	int num_devs;
	int enabled = 0;

	num_devs = snd_use_case_get_list(mgr->mgr, "_enadevs", &list);
	if (num_devs <= 0)
		return 0;

	for (i = 0; i < (unsigned int)num_devs; i++)
		if (!strcmp(dev, list[i])) {
			enabled = 1;
			break;
		}

	snd_use_case_free_list(list, num_devs);
	return enabled;
}

static int modifier_enabled(struct cras_use_case_mgr *mgr, const char *mod)
{
	const char **list;
	unsigned int mod_idx;
	int num_mods;

	num_mods = snd_use_case_get_list(mgr->mgr, "_enamods", &list);
	if (num_mods <= 0)
		return 0;

	for (mod_idx = 0; mod_idx < (unsigned int)num_mods; mod_idx++)
		if (!strcmp(mod, list[mod_idx]))
			break;

	snd_use_case_free_list(list, num_mods);
	return (mod_idx < (unsigned int)num_mods);
}

static int get_var(struct cras_use_case_mgr *mgr, const char *var,
		   const char *dev, const char *verb, const char **value)
{
	char *id;
	int rc;
	size_t len = strlen(var) + strlen(dev) + strlen(verb) + 4;

	id = (char *)malloc(len);
	if (!id)
		return -ENOMEM;
	snprintf(id, len, "=%s/%s/%s", var, dev, verb);
	rc = snd_use_case_get(mgr->mgr, id, value);

	free((void *)id);
	return rc;
}

static int get_int(struct cras_use_case_mgr *mgr, const char *var,
		   const char *dev, const char *verb, int *value)
{
	const char *str_value;
	int rc;

	if (!value)
		return -EINVAL;
	rc = get_var(mgr, var, dev, verb, &str_value);
	if (rc != 0)
		return rc;
	*value = atoi(str_value);
	free((void *)str_value);
	return 0;
}

static int ucm_set_modifier_enabled(struct cras_use_case_mgr *mgr,
				    const char *mod, int enable)
{
	return snd_use_case_set(mgr->mgr, enable ? "_enamod" : "_dismod", mod);
}

static int ucm_str_ends_with_suffix(const char *str, const char *suffix)
{
	if (!str || !suffix)
		return 0;
	size_t len_str = strlen(str);
	size_t len_suffix = strlen(suffix);
	if (len_suffix > len_str)
		return 0;
	return strncmp(str + len_str - len_suffix, suffix, len_suffix) == 0;
}

static int ucm_section_exists_with_name(struct cras_use_case_mgr *mgr,
					const char *name,
					const char *identifier)
{
	const char **list;
	unsigned int i;
	int num_entries;
	int exist = 0;

	num_entries = snd_use_case_get_list(mgr->mgr, identifier, &list);
	if (num_entries <= 0)
		return 0;

	for (i = 0; i < (unsigned int)num_entries; i += 2) {
		if (!list[i])
			continue;

		if (strcmp(list[i], name) == 0) {
			exist = 1;
			break;
		}
	}
	snd_use_case_free_list(list, num_entries);
	return exist;
}

static int ucm_section_exists_with_suffix(struct cras_use_case_mgr *mgr,
					  const char *suffix,
					  const char *identifier)
{
	const char **list;
	unsigned int i;
	int num_entries;
	int exist = 0;

	num_entries = snd_use_case_get_list(mgr->mgr, identifier, &list);
	if (num_entries <= 0)
		return 0;

	for (i = 0; i < (unsigned int)num_entries; i += 2) {
		if (!list[i])
			continue;

		if (ucm_str_ends_with_suffix(list[i], suffix)) {
			exist = 1;
			break;
		}
	}
	snd_use_case_free_list(list, num_entries);
	return exist;
}

static int ucm_mod_exists_with_suffix(struct cras_use_case_mgr *mgr,
				      const char *suffix)
{
	char *identifier;
	int rc;

	identifier = snd_use_case_identifier("_modifiers/%s", uc_verb(mgr));
	rc = ucm_section_exists_with_suffix(mgr, suffix, identifier);
	free(identifier);
	return rc;
}

static int ucm_mod_exists_with_name(struct cras_use_case_mgr *mgr,
				    const char *name)
{
	char *identifier;
	int rc;

	identifier = snd_use_case_identifier("_modifiers/%s", uc_verb(mgr));
	rc = ucm_section_exists_with_name(mgr, name, identifier);
	free(identifier);
	return rc;
}

/* Get a list of section names whose variable is the matched value. */
static struct section_name *
ucm_get_sections_for_var(struct cras_use_case_mgr *mgr, const char *var,
			 const char *value, const char *identifier,
			 enum CRAS_STREAM_DIRECTION direction)
{
	const char **list;
	struct section_name *section_names = NULL, *s_name;
	unsigned int i;
	int num_entries;
	int rc;

	num_entries = snd_use_case_get_list(mgr->mgr, identifier, &list);
	if (num_entries <= 0)
		return NULL;

	/* snd_use_case_get_list fills list with pairs of device name and
	 * comment, so device names are in even-indexed elements. */
	for (i = 0; i < (unsigned int)num_entries; i += 2) {
		const char *this_value;

		if (!list[i])
			continue;

		rc = get_var(mgr, var, list[i], uc_verb(mgr), &this_value);
		if (rc)
			continue;

		if (!strcmp(value, this_value)) {
			s_name = (struct section_name *)malloc(
				sizeof(struct section_name));

			if (!s_name) {
				syslog(LOG_ERR, "Failed to allocate memory");
				free((void *)this_value);
				break;
			}

			s_name->name = strdup(list[i]);
			DL_APPEND(section_names, s_name);
		}
		free((void *)this_value);
	}

	snd_use_case_free_list(list, num_entries);
	return section_names;
}

static struct section_name *
ucm_get_devices_for_var(struct cras_use_case_mgr *mgr, const char *var,
			const char *value, enum CRAS_STREAM_DIRECTION dir)
{
	char *identifier;
	struct section_name *section_names;

	identifier = snd_use_case_identifier("_devices/%s", uc_verb(mgr));
	section_names =
		ucm_get_sections_for_var(mgr, var, value, identifier, dir);
	free(identifier);
	return section_names;
}

static const char *ucm_get_value_for_dev(struct cras_use_case_mgr *mgr,
					 const char *value_var, const char *dev)
{
	const char *name = NULL;
	int rc;

	rc = get_var(mgr, value_var, dev, uc_verb(mgr), &name);
	if (rc)
		return NULL;

	return name;
}

static inline const char *
ucm_get_playback_device_name_for_dev(struct cras_use_case_mgr *mgr,
				     const char *dev)
{
	return ucm_get_value_for_dev(mgr, playback_device_name_var, dev);
}

static inline const char *
ucm_get_capture_device_name_for_dev(struct cras_use_case_mgr *mgr,
				    const char *dev)
{
	return ucm_get_value_for_dev(mgr, capture_device_name_var, dev);
}

/* Gets the value of DependentPCM property. This is used to structure two
 * SectionDevices under one cras iodev to avoid two PCMs be open at the
 * same time because of restriction in lower layer driver or hardware.
 */
static inline const char *
ucm_get_dependent_device_name_for_dev(struct cras_use_case_mgr *mgr,
				      const char *dev)
{
	return ucm_get_value_for_dev(mgr, dependent_device_name_var, dev);
}

/* Get a list of mixer names specified in a UCM variable separated by ",".
 * E.g. "Left Playback,Right Playback".
 */
static struct mixer_name *ucm_get_mixer_names(struct cras_use_case_mgr *mgr,
					      const char *dev, const char *var,
					      enum CRAS_STREAM_DIRECTION dir,
					      mixer_name_type type)
{
	const char *names_in_string = NULL;
	int rc;
	char *tokens, *name;
	char *laststr = NULL;
	struct mixer_name *names = NULL;

	rc = get_var(mgr, var, dev, uc_verb(mgr), &names_in_string);
	if (rc)
		return NULL;

	tokens = strdup(names_in_string);
	name = strtok_r(tokens, ",", &laststr);
	while (name != NULL) {
		names = mixer_name_add(names, name, dir, type);
		name = strtok_r(NULL, ",", &laststr);
	}
	free((void *)names_in_string);
	free(tokens);
	return names;
}

/* Exported Interface */

struct cras_use_case_mgr *ucm_create(const char *name)
{
	struct cras_use_case_mgr *mgr;
	int rc;
	const char **list;
	int num_verbs, i, j;

	assert_on_compile(ARRAY_SIZE(use_case_verbs) == CRAS_STREAM_NUM_TYPES);

	if (!name)
		return NULL;

	mgr = (struct cras_use_case_mgr *)malloc(sizeof(*mgr));
	if (!mgr)
		return NULL;

	rc = snd_use_case_mgr_open(&mgr->mgr, name);
	if (rc) {
		syslog(LOG_WARNING, "Can not open ucm for card %s, rc = %d",
		       name, rc);
		goto cleanup;
	}

	mgr->name = name;
	mgr->avail_use_cases = 0;
	num_verbs = snd_use_case_get_list(mgr->mgr, "_verbs", &list);
	for (i = 0; i < num_verbs; i += 2) {
		for (j = 0; j < CRAS_STREAM_NUM_TYPES; ++j) {
			if (strcmp(list[i], use_case_verbs[j]) == 0)
				break;
		}
		if (j < CRAS_STREAM_NUM_TYPES)
			mgr->avail_use_cases |= (1 << j);
	}
	if (num_verbs > 0)
		snd_use_case_free_list(list, num_verbs);

	rc = ucm_set_use_case(mgr, CRAS_STREAM_TYPE_DEFAULT);
	if (rc)
		goto cleanup_mgr;

	return mgr;

cleanup_mgr:
	snd_use_case_mgr_close(mgr->mgr);
cleanup:
	free(mgr);
	return NULL;
}

void ucm_destroy(struct cras_use_case_mgr *mgr)
{
	snd_use_case_mgr_close(mgr->mgr);
	free(mgr);
}

int ucm_set_use_case(struct cras_use_case_mgr *mgr,
		     enum CRAS_STREAM_TYPE use_case)
{
	int rc;

	if (mgr->avail_use_cases & (1 << use_case)) {
		mgr->use_case = use_case;
	} else {
		syslog(LOG_ERR, "Unavailable use case %d for card %s", use_case,
		       mgr->name);
		return -1;
	}

	rc = snd_use_case_set(mgr->mgr, "_verb", uc_verb(mgr));
	if (rc) {
		syslog(LOG_ERR, "Can not set verb %s for card %s, rc = %d",
		       uc_verb(mgr), mgr->name, rc);
		return rc;
	}

	return 0;
}

int ucm_swap_mode_exists(struct cras_use_case_mgr *mgr)
{
	return ucm_mod_exists_with_suffix(mgr, swap_mode_suffix);
}

int ucm_enable_swap_mode(struct cras_use_case_mgr *mgr, const char *node_name,
			 int enable)
{
	char *swap_mod = NULL;
	int rc;
	size_t len = strlen(node_name) + 1 + strlen(swap_mode_suffix) + 1;
	swap_mod = (char *)malloc(len);
	if (!swap_mod)
		return -ENOMEM;
	snprintf(swap_mod, len, "%s %s", node_name, swap_mode_suffix);
	if (!ucm_mod_exists_with_name(mgr, swap_mod)) {
		syslog(LOG_ERR, "Can not find swap mode modifier %s.",
		       swap_mod);
		free((void *)swap_mod);
		return -EPERM;
	}
	if (modifier_enabled(mgr, swap_mod) == !!enable) {
		free((void *)swap_mod);
		return 0;
	}
	rc = ucm_set_modifier_enabled(mgr, swap_mod, enable);
	free((void *)swap_mod);
	return rc;
}

int ucm_set_enabled(struct cras_use_case_mgr *mgr, const char *dev, int enable)
{
	int rc;
	if (device_enabled(mgr, dev) == !!enable)
		return 0;
	syslog(LOG_DEBUG, "UCM %s %s", enable ? "enable" : "disable", dev);
	rc = snd_use_case_set(mgr->mgr, enable ? "_enadev" : "_disdev", dev);
	if (rc && (rc != -ENOENT || ucm_has_fully_specified_ucm_flag(mgr))) {
		syslog(LOG_ERR, "Can not %s UCM for device %s, rc = %d",
		       enable ? "enable" : "disable", dev, rc);
	}
	return rc;
}

char *ucm_get_flag(struct cras_use_case_mgr *mgr, const char *flag_name)
{
	char *flag_value = NULL;
	const char *value;
	int rc;

	/* Set device to empty string since flag is specified in verb section */
	rc = get_var(mgr, flag_name, "", uc_verb(mgr), &value);
	if (!rc) {
		flag_value = strdup(value);
		free((void *)value);
	}

	return flag_value;
}

char *ucm_get_cap_control(struct cras_use_case_mgr *mgr, const char *ucm_dev)
{
	char *control_name = NULL;
	const char *value;
	int rc;

	rc = get_var(mgr, cap_var, ucm_dev, uc_verb(mgr), &value);
	if (!rc) {
		control_name = strdup(value);
		free((void *)value);
	}

	return control_name;
}

inline const char *ucm_get_override_type_name(struct cras_use_case_mgr *mgr,
					      const char *dev)
{
	return ucm_get_value_for_dev(mgr, override_type_name_var, dev);
}

char *ucm_get_dev_for_jack(struct cras_use_case_mgr *mgr, const char *jack,
			   enum CRAS_STREAM_DIRECTION direction)
{
	struct section_name *section_names, *c;
	char *ret = NULL;

	section_names =
		ucm_get_devices_for_var(mgr, jack_dev_var, jack, direction);

	DL_FOREACH (section_names, c) {
		if (!strcmp(c->name, "Mic")) {
			/* Skip mic section for output */
			if (direction == CRAS_STREAM_OUTPUT)
				continue;
		} else {
			/* Only check mic for input. */
			if (direction == CRAS_STREAM_INPUT)
				continue;
		}
		ret = strdup(c->name);
		break;
	}

	DL_FOREACH (section_names, c) {
		DL_DELETE(section_names, c);
		free((void *)c->name);
		free(c);
	}

	return ret;
}

char *ucm_get_dev_for_mixer(struct cras_use_case_mgr *mgr, const char *mixer,
			    enum CRAS_STREAM_DIRECTION dir)
{
	struct section_name *section_names = NULL, *c;
	char *ret = NULL;

	if (dir == CRAS_STREAM_OUTPUT) {
		section_names = ucm_get_devices_for_var(
			mgr, playback_mixer_elem_var, mixer, dir);
	} else if (dir == CRAS_STREAM_INPUT) {
		section_names = ucm_get_devices_for_var(
			mgr, capture_mixer_elem_var, mixer, dir);
	}

	if (section_names)
		ret = strdup(section_names->name);

	DL_FOREACH (section_names, c) {
		DL_DELETE(section_names, c);
		free((void *)c->name);
		free(c);
	}

	return ret;
}

inline const char *ucm_get_edid_file_for_dev(struct cras_use_case_mgr *mgr,
					     const char *dev)
{
	return ucm_get_value_for_dev(mgr, edid_var, dev);
}

inline const char *ucm_get_dsp_name_for_dev(struct cras_use_case_mgr *mgr,
					    const char *dev)
{
	return ucm_get_value_for_dev(mgr, dsp_name_var, dev);
}

int ucm_get_min_buffer_level(struct cras_use_case_mgr *mgr, unsigned int *level)
{
	int value;
	int rc;

	rc = get_int(mgr, min_buffer_level_var, "", uc_verb(mgr), &value);
	if (rc)
		return -ENOENT;
	*level = value;

	return 0;
}

unsigned int ucm_get_disable_software_volume(struct cras_use_case_mgr *mgr)
{
	int value;
	int rc;

	rc = get_int(mgr, disable_software_volume, "", uc_verb(mgr), &value);
	if (rc)
		return 0;

	return value;
}

int ucm_get_default_node_gain(struct cras_use_case_mgr *mgr, const char *dev,
			      long *gain)
{
	int value;
	int rc;

	rc = get_int(mgr, default_node_gain, dev, uc_verb(mgr), &value);
	if (rc)
		return rc;
	*gain = value;
	return 0;
}

int ucm_get_intrinsic_sensitivity(struct cras_use_case_mgr *mgr,
				  const char *dev, long *sensitivity)
{
	int value;
	int rc;

	rc = get_int(mgr, intrinsic_sensitivity_var, dev, uc_verb(mgr), &value);
	if (rc)
		return rc;
	*sensitivity = value;
	return 0;
}

int ucm_get_preempt_hotword(struct cras_use_case_mgr *mgr, const char *dev)
{
	int value;
	int rc;

	rc = get_int(mgr, preempt_hotword_var, dev, uc_verb(mgr), &value);
	if (rc)
		return 0;
	return value;
}

static int get_device_index_from_target(const char *target_device_name);

int ucm_get_alsa_dev_idx_for_dev(struct cras_use_case_mgr *mgr, const char *dev,
				 enum CRAS_STREAM_DIRECTION direction)
{
	const char *pcm_name = NULL;
	int dev_idx = -1;

	if (direction == CRAS_STREAM_OUTPUT)
		pcm_name = ucm_get_playback_device_name_for_dev(mgr, dev);
	else if (direction == CRAS_STREAM_INPUT)
		pcm_name = ucm_get_capture_device_name_for_dev(mgr, dev);

	if (pcm_name) {
		dev_idx = get_device_index_from_target(pcm_name);
		free((void *)pcm_name);
	}
	return dev_idx;
}

inline const char *
ucm_get_echo_reference_dev_name_for_dev(struct cras_use_case_mgr *mgr,
					const char *dev)
{
	return ucm_get_value_for_dev(mgr, echo_reference_dev_name_var, dev);
}

int ucm_get_sample_rate_for_dev(struct cras_use_case_mgr *mgr, const char *dev,
				enum CRAS_STREAM_DIRECTION direction)
{
	int value;
	int rc;
	const char *var_name;

	if (direction == CRAS_STREAM_OUTPUT)
		var_name = playback_device_rate_var;
	else if (direction == CRAS_STREAM_INPUT)
		var_name = capture_device_rate_var;
	else
		return -EINVAL;

	rc = get_int(mgr, var_name, dev, uc_verb(mgr), &value);
	if (rc)
		return rc;

	return value;
}

int ucm_get_channels_for_dev(struct cras_use_case_mgr *mgr, const char *dev,
			     enum CRAS_STREAM_DIRECTION direction,
			     size_t *channels)
{
	int value;
	int rc;
	const char *var_name;

	if (direction == CRAS_STREAM_OUTPUT)
		var_name = playback_channels_var;
	else if (direction == CRAS_STREAM_INPUT)
		var_name = capture_channels_var;
	else
		return -EINVAL;

	rc = get_int(mgr, var_name, dev, uc_verb(mgr), &value);
	if (rc)
		return rc;
	if (value < 0)
		return -1;

	*channels = (size_t)value;
	return 0;
}

int ucm_get_capture_chmap_for_dev(struct cras_use_case_mgr *mgr,
				  const char *dev, int8_t *channel_layout)
{
	const char *var_str;
	char *tokens, *token;
	int i, rc;

	rc = get_var(mgr, capture_channel_map_var, dev, uc_verb(mgr), &var_str);
	if (rc)
		return rc;

	tokens = strdup(var_str);
	token = strtok(tokens, " ");
	for (i = 0; token && (i < CRAS_CH_MAX); i++) {
		channel_layout[i] = atoi(token);
		token = strtok(NULL, " ");
	}

	free((void *)tokens);
	free((void *)var_str);
	return (i == CRAS_CH_MAX) ? 0 : -EINVAL;
}

struct mixer_name *ucm_get_coupled_mixer_names(struct cras_use_case_mgr *mgr,
					       const char *dev)
{
	return ucm_get_mixer_names(mgr, dev, coupled_mixers, CRAS_STREAM_OUTPUT,
				   MIXER_NAME_VOLUME);
}

static int get_device_index_from_target(const char *target_device_name)
{
	/* Expects a string in the form: hw:card-name,<num> */
	const char *pos = target_device_name;
	if (!pos)
		return -1;
	while (*pos && *pos != ',')
		++pos;
	if (*pos == ',') {
		++pos;
		return atoi(pos);
	}
	return -1;
}

static const char *ucm_get_dir_for_device(struct cras_use_case_mgr *mgr,
					  const char *dev_name,
					  enum CRAS_STREAM_DIRECTION *dir)
{
	const char *pcm_name;

	pcm_name = ucm_get_playback_device_name_for_dev(mgr, dev_name);

	if (pcm_name) {
		*dir = CRAS_STREAM_OUTPUT;
		return pcm_name;
	}

	pcm_name = ucm_get_capture_device_name_for_dev(mgr, dev_name);
	if (pcm_name) {
		*dir = CRAS_STREAM_INPUT;
		return pcm_name;
	}

	*dir = CRAS_STREAM_UNDEFINED;
	return NULL;
}

static int ucm_parse_device_section(struct cras_use_case_mgr *mgr,
				    const char *dev,
				    struct ucm_section **sections)
{
	enum CRAS_STREAM_DIRECTION dir;
	int dev_idx = -1;
	int dependent_dev_idx = -1;
	const char *jack_name = NULL;
	const char *jack_type = NULL;
	const char *jack_dev = NULL;
	const char *jack_control = NULL;
	const char *mixer_name = NULL;
	struct mixer_name *m_name;
	int rc = 0;
	const char *pcm_name;
	const char *dependent_dev_name = NULL;
	struct ucm_section *dev_sec;
	const char *dev_name;

	dev_name = strdup(dev);
	if (!dev_name)
		return 0;

	pcm_name = ucm_get_dir_for_device(mgr, dev_name, &dir);

	if (pcm_name)
		dev_idx = get_device_index_from_target(pcm_name);

	if (dir == CRAS_STREAM_UNDEFINED) {
		syslog(LOG_ERR,
		       "UCM configuration for device '%s' missing"
		       " PlaybackPCM or CapturePCM definition.",
		       dev_name);
		rc = -EINVAL;
		goto error_cleanup;
	}

	dependent_dev_name =
		ucm_get_dependent_device_name_for_dev(mgr, dev_name);
	if (dependent_dev_name) {
		dependent_dev_idx =
			get_device_index_from_target(dependent_dev_name);
	}

	jack_dev = ucm_get_jack_dev_for_dev(mgr, dev_name);
	jack_control = ucm_get_jack_control_for_dev(mgr, dev_name);
	if (dir == CRAS_STREAM_OUTPUT)
		mixer_name = ucm_get_playback_mixer_elem_for_dev(mgr, dev_name);
	else if (dir == CRAS_STREAM_INPUT)
		mixer_name = ucm_get_capture_mixer_elem_for_dev(mgr, dev_name);

	if (jack_dev) {
		jack_name = jack_dev;
		jack_type = "gpio";
	} else if (jack_control) {
		jack_name = jack_control;
		jack_type = "hctl";
	}

	dev_sec = ucm_section_create(dev_name, pcm_name, dev_idx,
				     dependent_dev_idx, dir, jack_name,
				     jack_type);

	if (!dev_sec) {
		syslog(LOG_ERR, "Failed to allocate memory.");
		rc = -ENOMEM;
		goto error_cleanup;
	}

	dev_sec->jack_switch = ucm_get_jack_switch_for_dev(mgr, dev_name);

	if (mixer_name) {
		rc = ucm_section_set_mixer_name(dev_sec, mixer_name);
		if (rc)
			goto error_cleanup;
	}

	m_name = ucm_get_mixer_names(mgr, dev_name, coupled_mixers, dir,
				     MIXER_NAME_VOLUME);
	ucm_section_concat_coupled(dev_sec, m_name);

	DL_APPEND(*sections, dev_sec);
	ucm_section_dump(dev_sec);
error_cleanup:
	free((void *)dev_name);
	free((void *)dependent_dev_name);
	free((void *)jack_dev);
	free((void *)jack_control);
	free((void *)mixer_name);
	free((void *)pcm_name);
	return rc;
}

struct ucm_section *ucm_get_sections(struct cras_use_case_mgr *mgr)
{
	struct ucm_section *sections = NULL;
	const char **list;
	int num_devs;
	int i;
	char *identifier;

	/* Find the list of all mixers using the control names defined in
	 * the header definintion for this function.  */
	identifier = snd_use_case_identifier("_devices/%s", uc_verb(mgr));
	num_devs = snd_use_case_get_list(mgr->mgr, identifier, &list);
	free(identifier);

	/* snd_use_case_get_list fills list with pairs of device name and
	 * comment, so device names are in even-indexed elements. */
	for (i = 0; i < num_devs; i += 2) {
		if (ucm_parse_device_section(mgr, list[i], &sections) < 0) {
			ucm_section_free_list(sections);
			sections = NULL;
			break;
		}
	}

	if (num_devs > 0)
		snd_use_case_free_list(list, num_devs);
	return sections;
}

char *ucm_get_hotword_models(struct cras_use_case_mgr *mgr)
{
	const char **list;
	int i, num_entries;
	int models_len = 0;
	char *models = NULL;
	const char *model_name;
	char *identifier;

	identifier = snd_use_case_identifier("_modifiers/%s", uc_verb(mgr));
	num_entries = snd_use_case_get_list(mgr->mgr, identifier, &list);
	free(identifier);

	if (num_entries <= 0)
		return 0;

	models = (char *)malloc(num_entries *
				(CRAS_MAX_HOTWORD_MODEL_NAME_SIZE + 1));

	for (i = 0; i < num_entries; i += 2) {
		if (!list[i])
			continue;

		if (strncmp(list[i], hotword_model_prefix,
			    strlen(hotword_model_prefix)))
			continue;

		model_name = list[i] + strlen(hotword_model_prefix);
		while (isspace(*model_name))
			model_name++;

		if (strlen(model_name) > CRAS_MAX_HOTWORD_MODEL_NAME_SIZE) {
			syslog(LOG_ERR,
			       "Ignore hotword model %s because the it is"
			       "too long.",
			       list[i]);
			continue;
		}

		if (models_len != 0)
			models[models_len++] = ',';

		strcpy(models + models_len, model_name);
		models_len += strlen(model_name);
	}
	models[models_len++] = 0;
	snd_use_case_free_list(list, num_entries);

	return models;
}

int ucm_set_hotword_model(struct cras_use_case_mgr *mgr, const char *model)
{
	const char **list;
	int num_enmods, mod_idx;
	char *model_mod = NULL;
	size_t model_mod_size =
		strlen(model) + 1 + strlen(hotword_model_prefix) + 1;
	model_mod = (char *)malloc(model_mod_size);
	if (!model_mod)
		return -ENOMEM;
	snprintf(model_mod, model_mod_size, "%s %s", hotword_model_prefix,
		 model);
	if (!ucm_mod_exists_with_name(mgr, model_mod)) {
		free((void *)model_mod);
		return -EINVAL;
	}

	/* Disable all currently enabled horword model modifiers. */
	num_enmods = snd_use_case_get_list(mgr->mgr, "_enamods", &list);
	if (num_enmods <= 0)
		goto enable_mod;

	for (mod_idx = 0; mod_idx < num_enmods; mod_idx++) {
		if (!strncmp(list[mod_idx], hotword_model_prefix,
			     strlen(hotword_model_prefix)))
			ucm_set_modifier_enabled(mgr, list[mod_idx], 0);
	}
	snd_use_case_free_list(list, num_enmods);

enable_mod:
	ucm_set_modifier_enabled(mgr, model_mod, 1);
	free((void *)model_mod);
	return 0;
}

int ucm_has_fully_specified_ucm_flag(struct cras_use_case_mgr *mgr)
{
	char *flag;
	int ret = 0;
	flag = ucm_get_flag(mgr, fully_specified_ucm_var);
	if (!flag)
		return 0;
	ret = !strcmp(flag, "1");
	free(flag);
	return ret;
}

inline const char *
ucm_get_playback_mixer_elem_for_dev(struct cras_use_case_mgr *mgr,
				    const char *dev)
{
	return ucm_get_value_for_dev(mgr, playback_mixer_elem_var, dev);
}

inline const char *
ucm_get_capture_mixer_elem_for_dev(struct cras_use_case_mgr *mgr,
				   const char *dev)
{
	return ucm_get_value_for_dev(mgr, capture_mixer_elem_var, dev);
}

struct mixer_name *ucm_get_main_volume_names(struct cras_use_case_mgr *mgr)
{
	return ucm_get_mixer_names(mgr, "", main_volume_names,
				   CRAS_STREAM_OUTPUT, MIXER_NAME_MAIN_VOLUME);
}

int ucm_list_section_devices_by_device_name(
	struct cras_use_case_mgr *mgr, enum CRAS_STREAM_DIRECTION direction,
	const char *device_name, ucm_list_section_devices_callback cb,
	void *cb_arg)
{
	int listed = 0;
	struct section_name *section_names, *c;
	const char *var;
	char *identifier;

	if (direction == CRAS_STREAM_OUTPUT)
		var = playback_device_name_var;
	else if (direction == CRAS_STREAM_INPUT)
		var = capture_device_name_var;
	else
		return 0;

	identifier = snd_use_case_identifier("_devices/%s", uc_verb(mgr));
	section_names = ucm_get_sections_for_var(mgr, var, device_name,
						 identifier, direction);
	free(identifier);
	if (!section_names)
		return 0;

	DL_FOREACH (section_names, c) {
		cb(c->name, cb_arg);
		listed++;
	}

	DL_FOREACH (section_names, c) {
		DL_DELETE(section_names, c);
		free((void *)c->name);
		free(c);
	}
	return listed;
}

inline const char *ucm_get_jack_control_for_dev(struct cras_use_case_mgr *mgr,
						const char *dev)
{
	return ucm_get_value_for_dev(mgr, jack_control_var, dev);
}

inline const char *ucm_get_jack_dev_for_dev(struct cras_use_case_mgr *mgr,
					    const char *dev)
{
	return ucm_get_value_for_dev(mgr, jack_dev_var, dev);
}

int ucm_get_jack_switch_for_dev(struct cras_use_case_mgr *mgr, const char *dev)
{
	int value;

	int rc = get_int(mgr, jack_switch_var, dev, uc_verb(mgr), &value);
	if (rc || value < 0)
		return -1;
	return value;
}

unsigned int ucm_get_dma_period_for_dev(struct cras_use_case_mgr *mgr,
					const char *dev)
{
	int value;

	int rc = get_int(mgr, dma_period_var, dev, uc_verb(mgr), &value);
	if (rc || value < 0)
		return 0;
	return value;
}