Audio: STFT Process: Add new SOF module

This module provides analysis and synthesis filters for
frequency domain processing. The used technique is short term
Fourier transform (STFT) and inverse STFT. The FFT length,
hop, and window type are configured with the bytes control
configuration blob.

WIP - the audio quality is not yet good enough

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

Author: singalsu

src/audio/CMakeLists.txt

@@ -86,6 +86,9 @@ if(NOT CONFIG_COMP_MODULE_SHARED_LIBRARY_BUILD)
 	if(CONFIG_COMP_SRC)
 		add_subdirectory(src)
 	endif()
+	if(CONFIG_COMP_STFT_PROCESS)
+		add_subdirectory(stft_process)
+	endif()
 	if(CONFIG_COMP_TDFB)
 		add_subdirectory(tdfb)
 	endif()

src/audio/Kconfig

@@ -151,6 +151,7 @@ rsource "selector/Kconfig"
 rsource "smart_amp/Kconfig"
 rsource "sound_dose/Kconfig"
 rsource "src/Kconfig"
+rsource "stft_process/Kconfig"
 rsource "tdfb/Kconfig"
 rsource "template/Kconfig"
 rsource "tensorflow/Kconfig"

src/audio/stft_process/CMakeLists.txt

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+if(CONFIG_COMP_STFT_PROCESS STREQUAL "m" AND DEFINED CONFIG_LLEXT)
+  add_subdirectory(llext ${PROJECT_BINARY_DIR}/stft_process_llext)
+  add_dependencies(app stft_process)
+else()
+  add_local_sources(sof stft_process.c)
+  add_local_sources(sof stft_process_setup.c)
+  add_local_sources(sof stft_process_common.c)
+  add_local_sources(sof stft_process-generic.c)
+
+  if(CONFIG_IPC_MAJOR_4)
+    add_local_sources(sof stft_process-ipc4.c)
+  endif()
+endif()

src/audio/stft_process/Kconfig

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+config COMP_STFT_PROCESS
+	tristate "Template example component"
+	default y
+        select MATH_32BIT_FFT
+	help
+	  Select for stft_process component. Reason for existence
+	  is to provide a minimal component example and use as
+	  placeholder in processing pipelines. As example processing
+	  it swaps or reverses the channels when the switch control
+	  is enabled.

src/audio/stft_process/llext/CMakeLists.txt

@@ -0,0 +1,11 @@
+# Copyright (c) 2025 Intel Corporation.
+# SPDX-License-Identifier: Apache-2.0
+
+sof_llext_build("stft_process_comp"
+	SOURCES	../stft_process.c
+		../stft_process_setup.c
+		../stft_process_common.c
+		../stft_process-generic.c
+		../stft_process-ipc4.c
+	LIB openmodules
+)

src/audio/stft_process/llext/llext.toml.h

@@ -0,0 +1,6 @@
+#include <tools/rimage/config/platform.toml>
+#define LOAD_TYPE "2"
+#include "../stft_process_comp.toml"
+
+[module]
+count = __COUNTER__