diff --git a/hal/Android.mk b/hal/Android.mk
index 8bb668a..346fcb6 100644
--- a/hal/Android.mk
+++ b/hal/Android.mk
@@ -64,6 +64,13 @@
     LOCAL_CFLAGS += -DNO_AUDIO_OUT
 endif
 
+ifeq ($(strip $(BOARD_SUPPORTS_SOUND_TRIGGER)),true)
+    LOCAL_CFLAGS += -DSOUND_TRIGGER_ENABLED
+    LOCAL_CFLAGS += -DSOUND_TRIGGER_PLATFORM_NAME=$(TARGET_BOARD_PLATFORM)
+    LOCAL_C_INCLUDES += $(TARGET_OUT_HEADERS)/mm-audio/sound_trigger
+    LOCAL_SRC_FILES += audio_extn/soundtrigger.c
+endif
+
 LOCAL_MODULE := audio.primary.$(TARGET_BOARD_PLATFORM)
 
 LOCAL_MODULE_RELATIVE_PATH := hw
diff --git a/hal/audio_extn/audio_extn.h b/hal/audio_extn/audio_extn.h
index 26c2fb4..e4f0374 100644
--- a/hal/audio_extn/audio_extn.h
+++ b/hal/audio_extn/audio_extn.h
@@ -38,4 +38,35 @@
                                     struct str_parms *parms);
 #endif
 
+#ifndef SOUND_TRIGGER_ENABLED
+#define audio_extn_sound_trigger_init(adev)                            (0)
+#define audio_extn_sound_trigger_deinit(adev)                          (0)
+#define audio_extn_sound_trigger_update_device_status(snd_dev, event)  (0)
+#define audio_extn_sound_trigger_set_parameters(adev, parms)           (0)
+#define audio_extn_sound_trigger_check_and_get_session(in)             (0)
+#define audio_extn_sound_trigger_stop_lab(in)                          (0)
+#define audio_extn_sound_trigger_read(in, buffer, bytes)               (0)
+
+#else
+
+enum st_event_type {
+    ST_EVENT_SND_DEVICE_FREE,
+    ST_EVENT_SND_DEVICE_BUSY,
+    ST_EVENT_STREAM_FREE,
+    ST_EVENT_STREAM_BUSY
+};
+typedef enum st_event_type st_event_type_t;
+
+int audio_extn_sound_trigger_init(struct audio_device *adev);
+void audio_extn_sound_trigger_deinit(struct audio_device *adev);
+void audio_extn_sound_trigger_update_device_status(snd_device_t snd_device,
+                                     st_event_type_t event);
+void audio_extn_sound_trigger_set_parameters(struct audio_device *adev,
+                                             struct str_parms *parms);
+void audio_extn_sound_trigger_check_and_get_session(struct stream_in *in);
+void audio_extn_sound_trigger_stop_lab(struct stream_in *in);
+int audio_extn_sound_trigger_read(struct stream_in *in, void *buffer,
+                                  size_t bytes);
+#endif
+
 #endif /* AUDIO_EXTN_H */
diff --git a/hal/audio_extn/soundtrigger.c b/hal/audio_extn/soundtrigger.c
new file mode 100644
index 0000000..4d09387
--- /dev/null
+++ b/hal/audio_extn/soundtrigger.c
@@ -0,0 +1,348 @@
+/*
+ * Copyright (C) 2015 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 "soundtrigger"
+/* #define LOG_NDEBUG 0 */
+#define LOG_NDDEBUG 0
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <dlfcn.h>
+#include <cutils/log.h>
+#include "audio_hw.h"
+#include "audio_extn.h"
+#include "platform.h"
+#include "platform_api.h"
+#include "sound_trigger_prop_intf.h"
+
+#define XSTR(x) STR(x)
+#define STR(x) #x
+
+struct sound_trigger_info  {
+    struct sound_trigger_session_info st_ses;
+    bool lab_stopped;
+    struct listnode list;
+};
+
+struct sound_trigger_audio_device {
+    void *lib_handle;
+    struct audio_device *adev;
+    sound_trigger_hw_call_back_t st_callback;
+    struct listnode st_ses_list;
+    pthread_mutex_t lock;
+};
+
+static struct sound_trigger_audio_device *st_dev;
+
+static struct sound_trigger_info *
+get_sound_trigger_info(int capture_handle)
+{
+    struct sound_trigger_info  *st_ses_info = NULL;
+    struct listnode *node;
+    ALOGV("%s: list %d capture_handle %d", __func__,
+           list_empty(&st_dev->st_ses_list), capture_handle);
+    list_for_each(node, &st_dev->st_ses_list) {
+        st_ses_info = node_to_item(node, struct sound_trigger_info , list);
+        if (st_ses_info->st_ses.capture_handle == capture_handle)
+            return st_ses_info;
+    }
+    return NULL;
+}
+
+int audio_hw_call_back(sound_trigger_event_type_t event,
+                       sound_trigger_event_info_t* config)
+{
+    int status = 0;
+    struct sound_trigger_info  *st_ses_info;
+
+    if (!st_dev)
+       return -EINVAL;
+
+    pthread_mutex_lock(&st_dev->lock);
+    switch (event) {
+    case ST_EVENT_SESSION_REGISTER:
+        if (!config) {
+            ALOGE("%s: NULL config", __func__);
+            status = -EINVAL;
+            break;
+        }
+        st_ses_info= calloc(1, sizeof(struct sound_trigger_info ));
+        if (!st_ses_info) {
+            ALOGE("%s: st_ses_info alloc failed", __func__);
+            status = -ENOMEM;
+            break;
+        }
+        memcpy(&st_ses_info->st_ses, &config->st_ses, sizeof (config->st_ses));
+        ALOGV("%s: add capture_handle %d pcm %p", __func__,
+              st_ses_info->st_ses.capture_handle, st_ses_info->st_ses.pcm);
+        list_add_tail(&st_dev->st_ses_list, &st_ses_info->list);
+        break;
+
+    case ST_EVENT_SESSION_DEREGISTER:
+        if (!config) {
+            ALOGE("%s: NULL config", __func__);
+            status = -EINVAL;
+            break;
+        }
+        st_ses_info = get_sound_trigger_info(config->st_ses.capture_handle);
+        if (!st_ses_info) {
+            ALOGE("%s: pcm %p not in the list!", __func__, config->st_ses.pcm);
+            status = -EINVAL;
+            break;
+        }
+        ALOGV("%s: remove capture_handle %d pcm %p", __func__,
+              st_ses_info->st_ses.capture_handle, st_ses_info->st_ses.pcm);
+        list_remove(&st_ses_info->list);
+        free(st_ses_info);
+        break;
+    default:
+        ALOGW("%s: Unknown event %d", __func__, event);
+        break;
+    }
+    pthread_mutex_unlock(&st_dev->lock);
+    return status;
+}
+
+int audio_extn_sound_trigger_read(struct stream_in *in, void *buffer,
+                       size_t bytes)
+{
+    int ret = -1;
+    struct sound_trigger_info  *st_info = NULL;
+    audio_event_info_t event;
+
+    if (!st_dev)
+       return ret;
+
+    if (!in->is_st_session_active) {
+        ALOGE(" %s: Sound trigger is not active", __func__);
+        goto exit;
+    }
+    if (in->standby)
+        in->standby = false;
+
+    pthread_mutex_lock(&st_dev->lock);
+    st_info = get_sound_trigger_info(in->capture_handle);
+    pthread_mutex_unlock(&st_dev->lock);
+    if (st_info) {
+        event.u.aud_info.ses_info = &st_info->st_ses;
+        event.u.aud_info.buf = buffer;
+        event.u.aud_info.num_bytes = bytes;
+        ret = st_dev->st_callback(AUDIO_EVENT_READ_SAMPLES, &event);
+    }
+
+exit:
+    if (ret) {
+        if (-ENETRESET == ret)
+            in->is_st_session_active = false;
+        memset(buffer, 0, bytes);
+        ALOGV("%s: read failed status %d - sleep", __func__, ret);
+        usleep((bytes * 1000000) / (audio_stream_in_frame_size((struct audio_stream_in *)in) *
+                                   in->config.rate));
+    }
+    return ret;
+}
+
+void audio_extn_sound_trigger_stop_lab(struct stream_in *in)
+{
+    int status = 0;
+    struct sound_trigger_info  *st_ses_info = NULL;
+    audio_event_info_t event;
+
+    if (!st_dev || !in)
+       return;
+
+    pthread_mutex_lock(&st_dev->lock);
+    st_ses_info = get_sound_trigger_info(in->capture_handle);
+    pthread_mutex_unlock(&st_dev->lock);
+    if (st_ses_info) {
+        event.u.ses_info = st_ses_info->st_ses;
+        ALOGV("%s: AUDIO_EVENT_STOP_LAB pcm %p", __func__, st_ses_info->st_ses.pcm);
+        st_dev->st_callback(AUDIO_EVENT_STOP_LAB, &event);
+    }
+}
+void audio_extn_sound_trigger_check_and_get_session(struct stream_in *in)
+{
+    struct sound_trigger_info  *st_ses_info = NULL;
+    struct listnode *node;
+
+    if (!st_dev || !in)
+       return;
+
+    pthread_mutex_lock(&st_dev->lock);
+    in->is_st_session = false;
+    ALOGV("%s: list %d capture_handle %d", __func__,
+          list_empty(&st_dev->st_ses_list), in->capture_handle);
+    list_for_each(node, &st_dev->st_ses_list) {
+        st_ses_info = node_to_item(node, struct sound_trigger_info , list);
+        if (st_ses_info->st_ses.capture_handle == in->capture_handle) {
+            in->pcm = st_ses_info->st_ses.pcm;
+            in->config = st_ses_info->st_ses.config;
+            in->channel_mask = audio_channel_in_mask_from_count(in->config.channels);
+            in->is_st_session = true;
+            in->is_st_session_active = true;
+            ALOGD("%s: capture_handle %d is sound trigger", __func__, in->capture_handle);
+            break;
+        }
+    }
+    pthread_mutex_unlock(&st_dev->lock);
+}
+
+void audio_extn_sound_trigger_update_device_status(snd_device_t snd_device,
+                                     st_event_type_t event)
+{
+    int device_type = -1;
+
+    if (!st_dev)
+       return;
+
+    if (snd_device >= SND_DEVICE_OUT_BEGIN &&
+        snd_device < SND_DEVICE_OUT_END)
+        device_type = PCM_PLAYBACK;
+    else if (snd_device >= SND_DEVICE_IN_BEGIN &&
+        snd_device < SND_DEVICE_IN_END)
+        device_type = PCM_CAPTURE;
+    else {
+        ALOGE("%s: invalid device 0x%x, for event %d",
+                           __func__, snd_device, event);
+        return;
+    }
+
+    ALOGI("%s: device 0x%x of type %d for Event %d",
+        __func__, snd_device, device_type, event);
+    if (device_type == PCM_CAPTURE) {
+        switch(event) {
+        case ST_EVENT_SND_DEVICE_FREE:
+            st_dev->st_callback(AUDIO_EVENT_CAPTURE_DEVICE_INACTIVE, NULL);
+            break;
+        case ST_EVENT_SND_DEVICE_BUSY:
+            st_dev->st_callback(AUDIO_EVENT_CAPTURE_DEVICE_ACTIVE, NULL);
+            break;
+        default:
+            ALOGW("%s:invalid event %d for device 0x%x",
+                                  __func__, event, snd_device);
+        }
+    }/*Events for output device, if required can be placed here in else*/
+}
+
+void audio_extn_sound_trigger_set_parameters(struct audio_device *adev __unused,
+                               struct str_parms *params)
+{
+    audio_event_info_t event;
+    char value[32];
+    int ret, val;
+
+    if(!st_dev || !params) {
+        ALOGE("%s: str_params NULL", __func__);
+        return;
+    }
+
+    ret = str_parms_get_str(params, "SND_CARD_STATUS", value,
+                            sizeof(value));
+    if (ret > 0) {
+        if (strstr(value, "OFFLINE")) {
+            event.u.status = SND_CARD_STATUS_OFFLINE;
+            st_dev->st_callback(AUDIO_EVENT_SSR, &event);
+        }
+        else if (strstr(value, "ONLINE")) {
+            event.u.status = SND_CARD_STATUS_ONLINE;
+            st_dev->st_callback(AUDIO_EVENT_SSR, &event);
+        }
+        else
+            ALOGE("%s: unknown snd_card_status", __func__);
+    }
+
+    ret = str_parms_get_str(params, "CPE_STATUS", value, sizeof(value));
+    if (ret > 0) {
+        if (strstr(value, "OFFLINE")) {
+            event.u.status = CPE_STATUS_OFFLINE;
+            st_dev->st_callback(AUDIO_EVENT_SSR, &event);
+        }
+        else if (strstr(value, "ONLINE")) {
+            event.u.status = CPE_STATUS_ONLINE;
+            st_dev->st_callback(AUDIO_EVENT_SSR, &event);
+        }
+        else
+            ALOGE("%s: unknown CPE status", __func__);
+    }
+
+    ret = str_parms_get_int(params, "SVA_NUM_SESSIONS", &val);
+    if (ret >= 0) {
+        event.u.value = val;
+        st_dev->st_callback(AUDIO_EVENT_NUM_ST_SESSIONS, &event);
+    }
+}
+
+int audio_extn_sound_trigger_init(struct audio_device *adev)
+{
+    int status = 0;
+    char sound_trigger_lib[100];
+    void *lib_handle;
+
+    ALOGI("%s: Enter", __func__);
+
+    st_dev = (struct sound_trigger_audio_device*)
+                        calloc(1, sizeof(struct sound_trigger_audio_device));
+    if (!st_dev) {
+        ALOGE("%s: ERROR. sound trigger alloc failed", __func__);
+        return -ENOMEM;
+    }
+
+    snprintf(sound_trigger_lib, sizeof(sound_trigger_lib),
+             "/system/vendor/lib/hw/sound_trigger.primary.%s.so",
+              XSTR(SOUND_TRIGGER_PLATFORM_NAME));
+
+    st_dev->lib_handle = dlopen(sound_trigger_lib, RTLD_NOW);
+
+    if (st_dev->lib_handle == NULL) {
+        ALOGE("%s: DLOPEN failed for %s. error = %s", __func__, sound_trigger_lib,
+                dlerror());
+        status = -EINVAL;
+        goto cleanup;
+    }
+    ALOGI("%s: DLOPEN successful for %s", __func__, sound_trigger_lib);
+
+    st_dev->st_callback = (sound_trigger_hw_call_back_t)
+              dlsym(st_dev->lib_handle, "sound_trigger_hw_call_back");
+
+    if (st_dev->st_callback == NULL) {
+       ALOGE("%s: ERROR. dlsym Error:%s sound_trigger_hw_call_back", __func__,
+               dlerror());
+       goto cleanup;
+    }
+
+    st_dev->adev = adev;
+    list_init(&st_dev->st_ses_list);
+
+    return 0;
+
+cleanup:
+    if (st_dev->lib_handle)
+        dlclose(st_dev->lib_handle);
+    free(st_dev);
+    st_dev = NULL;
+    return status;
+
+}
+
+void audio_extn_sound_trigger_deinit(struct audio_device *adev)
+{
+    ALOGI("%s: Enter", __func__);
+    if (st_dev && (st_dev->adev == adev) && st_dev->lib_handle) {
+        dlclose(st_dev->lib_handle);
+        free(st_dev);
+        st_dev = NULL;
+    }
+}
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index 9c6c1a2..74ed5aa 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -273,8 +273,15 @@
         return 0;
     }
 
+    /* due to the possibility of calibration overwrite between listen
+        and audio, notify sound trigger hal before audio calibration is sent */
+    audio_extn_sound_trigger_update_device_status(snd_device,
+                                    ST_EVENT_SND_DEVICE_BUSY);
+
     if (platform_send_audio_calibration(adev->platform, snd_device) < 0) {
         adev->snd_dev_ref_cnt[snd_device]--;
+        audio_extn_sound_trigger_update_device_status(snd_device,
+                                    ST_EVENT_SND_DEVICE_FREE);
         return -EINVAL;
     }
 
@@ -302,6 +309,9 @@
         const char * dev_path = platform_get_snd_device_name(snd_device);
         ALOGD("%s: snd_device(%d: %s)", __func__, snd_device, dev_path);
         audio_route_reset_and_update_path(adev->audio_route, dev_path);
+        audio_extn_sound_trigger_update_device_status(snd_device,
+                                        ST_EVENT_SND_DEVICE_FREE);
+
     }
     return 0;
 }
@@ -1733,6 +1743,13 @@
     int status = 0;
     ALOGV("%s: enter", __func__);
     pthread_mutex_lock(&in->lock);
+
+    if (!in->standby && in->is_st_session) {
+        ALOGD("%s: sound trigger pcm stop lab", __func__);
+        audio_extn_sound_trigger_stop_lab(in);
+        in->standby = true;
+    }
+
     if (!in->standby) {
         pthread_mutex_lock(&adev->lock);
         in->standby = true;
@@ -1819,6 +1836,14 @@
     int i, ret = -1;
 
     pthread_mutex_lock(&in->lock);
+    if (in->is_st_session) {
+        ALOGVV(" %s: reading on st session bytes=%d", __func__, bytes);
+        /* Read from sound trigger HAL */
+        audio_extn_sound_trigger_read(in, buffer, bytes);
+        pthread_mutex_unlock(&in->lock);
+        return bytes;
+    }
+
     if (in->standby) {
         pthread_mutex_lock(&adev->lock);
         ret = start_input_stream(in);
@@ -2358,7 +2383,7 @@
 }
 
 static int adev_open_input_stream(struct audio_hw_device *dev,
-                                  audio_io_handle_t handle __unused,
+                                  audio_io_handle_t handle,
                                   audio_devices_t devices,
                                   struct audio_config *config,
                                   struct audio_stream_in **stream_in,
@@ -2402,6 +2427,7 @@
     in->dev = adev;
     in->standby = 1;
     in->channel_mask = config->channel_mask;
+    in->capture_handle = handle;
 
     /* Update config params with the requested sample rate and channels */
     if (in->device == AUDIO_DEVICE_IN_TELEPHONY_RX) {
@@ -2444,6 +2470,9 @@
     in->config.channels = channel_count;
     in->config.rate = config->sample_rate;
 
+    /* This stream could be for sound trigger lab,
+       get sound trigger pcm if present */
+    audio_extn_sound_trigger_check_and_get_session(in);
 
     *stream_in = &in->stream;
     ALOGV("%s: exit", __func__);
@@ -2613,6 +2642,7 @@
     free(adev->snd_dev_ref_cnt);
     platform_deinit(adev->platform);
     audio_extn_extspk_deinit(adev->extspk);
+    audio_extn_sound_trigger_deinit(adev);
     for (i = 0; i < ARRAY_SIZE(adev->use_case_table); ++i) {
         pcm_params_free(adev->use_case_table[i]);
     }
@@ -2701,6 +2731,7 @@
     }
 
     adev->extspk = audio_extn_extspk_init(adev);
+    audio_extn_sound_trigger_init(adev);
 
     if (access(VISUALIZER_LIBRARY_PATH, R_OK) == 0) {
         adev->visualizer_lib = dlopen(VISUALIZER_LIBRARY_PATH, RTLD_NOW);
diff --git a/hal/audio_hw.h b/hal/audio_hw.h
index 1888aa1..7f58388 100644
--- a/hal/audio_hw.h
+++ b/hal/audio_hw.h
@@ -167,6 +167,10 @@
     bool enable_aec;
     bool enable_ns;
 
+    audio_io_handle_t capture_handle;
+    bool is_st_session;
+    bool is_st_session_active;
+
     struct audio_device *dev;
 };