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diff --git a/include/hotword_dsp_api.h b/include/hotword_dsp_api.h
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+/*
+ * Copyright 2019 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.
+ */
+
+#ifndef SPEECH_MICRO_API_HOTWORD_DSP_API_H_
+#define SPEECH_MICRO_API_HOTWORD_DSP_API_H_
+
+/*
+ * This API creates a global singleton behind the scenes. It's the caller's
+ * responsibility to store the contents of the hotword_memmap model file into
+ * aligned memory and pass its pointer to this library. Note that no additional
+ * memory is allocated and hotword_memmap will contain both the model and the
+ * scratch buffers.
+ */
+
+/* Specifies the required alignment for the hotword_memmap. */
+extern const int kGoogleHotwordRequiredDataAlignment;
+
+/*
+ * Called to set up the Google hotword algorithm. Returns 1 if successful, and 0
+ * otherwise.
+ */
+int GoogleHotwordDspInit(void *hotword_memmap);
+
+/*
+ * Call with every frame of samples to process. If a hotword is detected, this
+ * function returns 1 otherwise 0. The required preamble length will be set to
+ * the number of milliseconds of buffered audio to be transferred to the AP.
+ */
+int GoogleHotwordDspProcess(const void *samples, int num_samples,
+			    int *preamble_length_ms);
+
+/*
+ * If there's a break in the audio stream (e.g. when Sound Activity Detection is
+ * enabled), call this before any subsequent calls to GoogleHotwordDspProcess.
+ */
+void GoogleHotwordDspReset(void);
+
+/* Returns the maximum possible audio preamble length in miliseconds. */
+int GoogleHotwordDspGetMaximumAudioPreambleMs(void);
+
+/* Returns an internal version number that this library was built at. */
+extern int GoogleHotwordVersion(void);
+
+#endif  /* SPEECH_MICRO_API_HOTWORD_DSP_API_H_ */