diff --git a/modules/usbaudio/audio_hw.c b/modules/usbaudio/audio_hw.c
new file mode 100644
index 0000000..4022efd
--- /dev/null
+++ b/modules/usbaudio/audio_hw.c
@@ -0,0 +1,439 @@
+/*
+ * Copyright (C) 2012 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 "usb_audio_hw"
+/*#define LOG_NDEBUG 0*/
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <sys/time.h>
+#include <stdlib.h>
+
+#include <cutils/log.h>
+#include <cutils/str_parms.h>
+#include <cutils/properties.h>
+
+#include <hardware/hardware.h>
+#include <system/audio.h>
+#include <hardware/audio.h>
+
+#include <tinyalsa/asoundlib.h>
+
+struct pcm_config pcm_config = {
+    .channels = 2,
+    .rate = 44100,
+    .period_size = 1024,
+    .period_count = 4,
+    .format = PCM_FORMAT_S16_LE,
+};
+
+struct audio_device {
+    struct audio_hw_device hw_device;
+
+    pthread_mutex_t lock; /* see note below on mutex acquisition order */
+    int card;
+    int device;
+    bool standby;
+};
+
+struct stream_out {
+    struct audio_stream_out stream;
+
+    pthread_mutex_t lock; /* see note below on mutex acquisition order */
+    struct pcm *pcm;
+    bool standby;
+
+    struct audio_device *dev;
+};
+
+/**
+ * NOTE: when multiple mutexes have to be acquired, always respect the
+ * following order: hw device > out stream
+ */
+
+/* Helper functions */
+
+/* must be called with hw device and output stream mutexes locked */
+static int start_output_stream(struct stream_out *out)
+{
+    struct audio_device *adev = out->dev;
+    int i;
+
+    if ((adev->card < 0) || (adev->device < 0))
+        return -EINVAL;
+
+    out->pcm = pcm_open(adev->card, adev->device, PCM_OUT, &pcm_config);
+
+    if (out->pcm && !pcm_is_ready(out->pcm)) {
+        ALOGE("pcm_open() failed: %s", pcm_get_error(out->pcm));
+        pcm_close(out->pcm);
+        return -ENOMEM;
+    }
+
+    return 0;
+}
+
+/* API functions */
+
+static uint32_t out_get_sample_rate(const struct audio_stream *stream)
+{
+    return pcm_config.rate;
+}
+
+static int out_set_sample_rate(struct audio_stream *stream, uint32_t rate)
+{
+    return 0;
+}
+
+static size_t out_get_buffer_size(const struct audio_stream *stream)
+{
+    return pcm_config.period_size *
+           audio_stream_frame_size((struct audio_stream *)stream);
+}
+
+static uint32_t out_get_channels(const struct audio_stream *stream)
+{
+    return AUDIO_CHANNEL_OUT_STEREO;
+}
+
+static audio_format_t out_get_format(const struct audio_stream *stream)
+{
+    return AUDIO_FORMAT_PCM_16_BIT;
+}
+
+static int out_set_format(struct audio_stream *stream, audio_format_t format)
+{
+    return 0;
+}
+
+static int out_standby(struct audio_stream *stream)
+{
+    struct stream_out *out = (struct stream_out *)stream;
+
+    pthread_mutex_lock(&out->dev->lock);
+    pthread_mutex_lock(&out->lock);
+
+    if (!out->standby) {
+        pcm_close(out->pcm);
+        out->pcm = NULL;
+        out->standby = true;
+    }
+
+    pthread_mutex_unlock(&out->lock);
+    pthread_mutex_unlock(&out->dev->lock);
+
+    return 0;
+}
+
+static int out_dump(const struct audio_stream *stream, int fd)
+{
+    return 0;
+}
+
+static int out_set_parameters(struct audio_stream *stream, const char *kvpairs)
+{
+    struct stream_out *out = (struct stream_out *)stream;
+    struct audio_device *adev = out->dev;
+    struct str_parms *parms;
+    char value[32];
+    int ret;
+    int routing = 0;
+
+    parms = str_parms_create_str(kvpairs);
+    pthread_mutex_lock(&adev->lock);
+
+    adev->card = -1;
+    adev->device = -1;
+
+    ret = str_parms_get_str(parms, "card", value, sizeof(value));
+    if (ret >= 0)
+        adev->card = atoi(value);
+
+    ret = str_parms_get_str(parms, "device", value, sizeof(value));
+    if (ret >= 0)
+        adev->device = atoi(value);
+
+    pthread_mutex_unlock(&adev->lock);
+    str_parms_destroy(parms);
+
+    return 0;
+}
+
+static char * out_get_parameters(const struct audio_stream *stream, const char *keys)
+{
+    return strdup("");
+}
+
+static uint32_t out_get_latency(const struct audio_stream_out *stream)
+{
+    return (pcm_config.period_size * pcm_config.period_count * 1000) /
+            out_get_sample_rate(&stream->common);
+}
+
+static int out_set_volume(struct audio_stream_out *stream, float left,
+                          float right)
+{
+    return -ENOSYS;
+}
+
+static ssize_t out_write(struct audio_stream_out *stream, const void* buffer,
+                         size_t bytes)
+{
+    int ret;
+    struct stream_out *out = (struct stream_out *)stream;
+
+    pthread_mutex_lock(&out->dev->lock);
+    pthread_mutex_lock(&out->lock);
+    if (out->standby) {
+        ret = start_output_stream(out);
+        if (ret != 0) {
+            goto err;
+        }
+        out->standby = false;
+    }
+
+    pcm_write(out->pcm, (void *)buffer, bytes);
+
+    pthread_mutex_unlock(&out->lock);
+    pthread_mutex_unlock(&out->dev->lock);
+
+    return bytes;
+
+err:
+    pthread_mutex_unlock(&out->lock);
+
+    if (ret != 0) {
+        usleep(bytes * 1000000 / audio_stream_frame_size(&stream->common) /
+               out_get_sample_rate(&stream->common));
+    }
+
+    return bytes;
+}
+
+static int out_get_render_position(const struct audio_stream_out *stream,
+                                   uint32_t *dsp_frames)
+{
+    return -EINVAL;
+}
+
+static int out_add_audio_effect(const struct audio_stream *stream, effect_handle_t effect)
+{
+    return 0;
+}
+
+static int out_remove_audio_effect(const struct audio_stream *stream, effect_handle_t effect)
+{
+    return 0;
+}
+
+static int out_get_next_write_timestamp(const struct audio_stream_out *stream,
+                                        int64_t *timestamp)
+{
+    return -EINVAL;
+}
+
+static int adev_open_output_stream(struct audio_hw_device *dev,
+                                   uint32_t devices, audio_format_t *format,
+                                   uint32_t *channels, uint32_t *sample_rate,
+                                   struct audio_stream_out **stream_out)
+{
+    struct audio_device *adev = (struct audio_device *)dev;
+    struct stream_out *out;
+    int ret;
+
+    out = (struct stream_out *)calloc(1, sizeof(struct stream_out));
+    if (!out)
+        return -ENOMEM;
+
+    out->stream.common.get_sample_rate = out_get_sample_rate;
+    out->stream.common.set_sample_rate = out_set_sample_rate;
+    out->stream.common.get_buffer_size = out_get_buffer_size;
+    out->stream.common.get_channels = out_get_channels;
+    out->stream.common.get_format = out_get_format;
+    out->stream.common.set_format = out_set_format;
+    out->stream.common.standby = out_standby;
+    out->stream.common.dump = out_dump;
+    out->stream.common.set_parameters = out_set_parameters;
+    out->stream.common.get_parameters = out_get_parameters;
+    out->stream.common.add_audio_effect = out_add_audio_effect;
+    out->stream.common.remove_audio_effect = out_remove_audio_effect;
+    out->stream.get_latency = out_get_latency;
+    out->stream.set_volume = out_set_volume;
+    out->stream.write = out_write;
+    out->stream.get_render_position = out_get_render_position;
+    out->stream.get_next_write_timestamp = out_get_next_write_timestamp;
+
+    out->dev = adev;
+
+    *format = out_get_format(&out->stream.common);
+    *channels = out_get_channels(&out->stream.common);
+    *sample_rate = out_get_sample_rate(&out->stream.common);
+
+    out->standby = true;
+
+    *stream_out = &out->stream;
+    return 0;
+
+err_open:
+    free(out);
+    *stream_out = NULL;
+    return ret;
+}
+
+static void adev_close_output_stream(struct audio_hw_device *dev,
+                                     struct audio_stream_out *stream)
+{
+    struct stream_out *out = (struct stream_out *)stream;
+
+    out_standby(&stream->common);
+    free(stream);
+}
+
+static int adev_set_parameters(struct audio_hw_device *dev, const char *kvpairs)
+{
+    return 0;
+}
+
+static char * adev_get_parameters(const struct audio_hw_device *dev,
+                                  const char *keys)
+{
+    return strdup("");
+}
+
+static int adev_init_check(const struct audio_hw_device *dev)
+{
+    return 0;
+}
+
+static int adev_set_voice_volume(struct audio_hw_device *dev, float volume)
+{
+    return -ENOSYS;
+}
+
+static int adev_set_master_volume(struct audio_hw_device *dev, float volume)
+{
+    return -ENOSYS;
+}
+
+static int adev_set_mode(struct audio_hw_device *dev, audio_mode_t mode)
+{
+    return 0;
+}
+
+static int adev_set_mic_mute(struct audio_hw_device *dev, bool state)
+{
+    return -ENOSYS;
+}
+
+static int adev_get_mic_mute(const struct audio_hw_device *dev, bool *state)
+{
+    return -ENOSYS;
+}
+
+static size_t adev_get_input_buffer_size(const struct audio_hw_device *dev,
+                                         uint32_t sample_rate, audio_format_t format,
+                                         int channel_count)
+{
+    return 0;
+}
+
+static int adev_open_input_stream(struct audio_hw_device *dev, uint32_t devices,
+                                  audio_format_t *format, uint32_t *channel_mask,
+                                  uint32_t *sample_rate,
+                                  audio_in_acoustics_t acoustics,
+                                  struct audio_stream_in **stream_in)
+{
+    return -ENOSYS;
+}
+
+static void adev_close_input_stream(struct audio_hw_device *dev,
+                                   struct audio_stream_in *stream)
+{
+}
+
+static int adev_dump(const audio_hw_device_t *device, int fd)
+{
+    return 0;
+}
+
+static int adev_close(hw_device_t *device)
+{
+    struct audio_device *adev = (struct audio_device *)device;
+
+    free(device);
+    return 0;
+}
+
+static uint32_t adev_get_supported_devices(const struct audio_hw_device *dev)
+{
+    return AUDIO_DEVICE_OUT_ALL_USB;
+}
+
+static int adev_open(const hw_module_t* module, const char* name,
+                     hw_device_t** device)
+{
+    struct audio_device *adev;
+    int ret;
+
+    if (strcmp(name, AUDIO_HARDWARE_INTERFACE) != 0)
+        return -EINVAL;
+
+    adev = calloc(1, sizeof(struct audio_device));
+    if (!adev)
+        return -ENOMEM;
+
+    adev->hw_device.common.tag = HARDWARE_DEVICE_TAG;
+    adev->hw_device.common.version = 0;
+    adev->hw_device.common.module = (struct hw_module_t *) module;
+    adev->hw_device.common.close = adev_close;
+
+    adev->hw_device.get_supported_devices = adev_get_supported_devices;
+    adev->hw_device.init_check = adev_init_check;
+    adev->hw_device.set_voice_volume = adev_set_voice_volume;
+    adev->hw_device.set_master_volume = adev_set_master_volume;
+    adev->hw_device.set_mode = adev_set_mode;
+    adev->hw_device.set_mic_mute = adev_set_mic_mute;
+    adev->hw_device.get_mic_mute = adev_get_mic_mute;
+    adev->hw_device.set_parameters = adev_set_parameters;
+    adev->hw_device.get_parameters = adev_get_parameters;
+    adev->hw_device.get_input_buffer_size = adev_get_input_buffer_size;
+    adev->hw_device.open_output_stream = adev_open_output_stream;
+    adev->hw_device.close_output_stream = adev_close_output_stream;
+    adev->hw_device.open_input_stream = adev_open_input_stream;
+    adev->hw_device.close_input_stream = adev_close_input_stream;
+    adev->hw_device.dump = adev_dump;
+
+    *device = &adev->hw_device.common;
+
+    return 0;
+}
+
+static struct hw_module_methods_t hal_module_methods = {
+    .open = adev_open,
+};
+
+struct audio_module HAL_MODULE_INFO_SYM = {
+    .common = {
+        .tag = HARDWARE_MODULE_TAG,
+        .version_major = 1,
+        .version_minor = 0,
+        .id = AUDIO_HARDWARE_MODULE_ID,
+        .name = "USB audio HW HAL",
+        .author = "The Android Open Source Project",
+        .methods = &hal_module_methods,
+    },
+};