modules: tensorflow: Add initial tensorflow micro module

This is WIP and adds a TFLM module based on micro_speech example to
do audio classification.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

Author: lrgirdwo

app/boards/intel_adsp_ace15_mtpm.conf

@@ -57,6 +57,8 @@ CONFIG_LIBRARY_MANAGER=y
 CONFIG_LIBRARY_AUTH_SUPPORT=y
 CONFIG_LIBRARY_BASE_ADDRESS=0xa0688000
 CONFIG_LIBRARY_BUILD_LIB=y
+CONFIG_CPP=y
+CONFIG_STD_CPP17=y
 
 # SOF / logging
 CONFIG_SOF_LOG_LEVEL_INF=y

app/configs/mtl/modules.conf

@@ -21,3 +21,4 @@ CONFIG_COMP_MULTIBAND_DRC=m
 CONFIG_COMP_GOOGLE_CTC_AUDIO_PROCESSING=m
 CONFIG_COMP_GOOGLE_RTC_AUDIO_PROCESSING=m
 CONFIG_COMP_TESTER=m
+CONFIG_COMP_TFMICRO=m

scripts/tensorflow-clone.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2025 Intel Corporation. All rights reserved.
+
+# fail immediately on any errors
+set -e
+
+# Array of TFLM Git repository URLs.  Add or remove repositories as needed.
+declare -a REPOS=(
+    "https://github.com/thesofproject/nnlib-hifi4"
+    "https://github.com/tensorflow/tflite-micro"
+    "https://github.com/thesofproject/flatbuffers"
+    "https://github.com/google/gemmlowp"
+    "https://github.com/google/ruy"
+)
+
+# Commit ID to check for (optional). If specified, the script will update
+# the repository if this commit ID is not found.  Leave empty to skip.
+declare -a COMMIT_ID=(
+    "cdedfb1a1044eb774915de21b63a1b6aa93276f6"
+    "e86d97b6237f88ab5925c0b41e3e3589a1560d86"
+    "f5acabf4e1a3fcba024081bb1871a2ed59aa1c28"
+    "719139ce755a0f31cbf1c37f7f98adcc7fc9f425"
+    "d37128311b445e758136b8602d1bbd2a755e115d"
+)
+
+# Directory where repositories will be cloned/updated.
+BASE_DIR="$HOME/work/sof"  # Or any other desired location
+
+# Function to check if a commit ID exists in a repository
+check_commit() {
+    local repo_dir="$1"
+    local commit_id="$2"
+
+    if [ -z "$commit_id" ]; then
+        return 0  # Skip check if no commit ID is provided
+    fi
+
+    if ! git -C "$repo_dir" rev-parse --quiet --verify "$commit_id" >/dev/null 2>&1; then
+        return 1  # Commit ID not found
+    else
+        return 0  # Commit ID found
+    fi
+}
+
+
+# Function to update the repository
+update_repo() {
+    local repo_dir="$1"
+    echo "Updating repository: $repo_dir"
+    git -C "$repo_dir" fetch --all
+    git -C "$repo_dir" pull
+}
+
+# Main script logic
+mkdir -p "$BASE_DIR"
+
+for ((i = 0; i < ${#REPOS[@]}; i++)); do
+    echo "Counter: $i, Value: ${REPOS[i]}"
+    repo_url=${REPOS[i]}
+
+    repo_name=$(basename "$repo_url" .git)  # Extract repo name
+    repo_dir="$BASE_DIR/$repo_name"
+
+    if [ ! -d "$repo_dir" ]; then
+        echo "Cloning repository: $repo_url"
+        git clone "$repo_url" "$repo_dir" || { echo "git clone failed for $repo_url"; exit 1; }
+    elif ! check_commit "$repo_dir" "${COMMIT_ID[i]}"; then
+        update_repo "$repo_dir"
+    else
+        echo "Repository $repo_name is up to date."
+    fi
+done
+
+echo "All repositories processed."

src/audio/CMakeLists.txt

@@ -89,6 +89,9 @@ if(NOT CONFIG_COMP_MODULE_SHARED_LIBRARY_BUILD)
 	if(CONFIG_COMP_VOLUME)
 		add_subdirectory(volume)
 	endif()
+	if(CONFIG_COMP_TFMICRO)
+		add_subdirectory(tfmicro)
+	endif()
 	if(CONFIG_ZEPHYR_NATIVE_DRIVERS)
 		list(APPEND base_files host-zephyr.c)
 		sof_list_append_ifdef(CONFIG_COMP_DAI base_files dai-zephyr.c)
@@ -146,6 +149,9 @@ if(NOT CONFIG_COMP_MODULE_SHARED_LIBRARY_BUILD)
 	if(CONFIG_DTS_CODEC)
 		add_subdirectory(codec)
 	endif()
+	if(CONFIG_COMP_TFMICRO)
+		add_subdirectory(tfmicro)
+	endif()
 
 	return()
 endif()

src/audio/Kconfig

@@ -143,6 +143,8 @@ rsource "asrc/Kconfig"
 
 rsource "tdfb/Kconfig"
 
+rsource "tfmicro/Kconfig"
+
 config COMP_MODULE_ADAPTER
 	bool "Module adapter"
 	default y

src/audio/tfmicro/CMakeLists.txt

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+config COMP_TFMICRO
+	tristate "Tensorflow Micro component"
+	default n
+	help
+	  Select for Tensorflow component support.

src/audio/tfmicro/Kconfig

@@ -0,0 +1,35 @@
+# SOF Tensorflow Micro Integration
+
+The TFLM module integrates tensorflow micro into SOF as an audio classifiction and in the future an audio processing module. This module is currently still work in progress, and needs a few features to be completed before its ready for production.
+
+## Building
+
+Please run ```./scripts/tensorflow-clone.sh``` before building as this will clone all dependecies required to build tensor flow micro with optimized xtensa kernels.
+
+To build as built-in, select ```CONFIG_COMP_TFMICRO=y``` in Kconfig and build.
+
+To build as a module, select ```CONFIG_COMP_TFMICRO=m``` in Kconfig and the build. This will build the llext module but currently this module will be missing symbols from tfmicro and nnlib archives. A manual step needs done to link in those symbols. i.e.
+
+```cd build-mtl/zephyr/tfmicro```
+
+```xt-clang++ -flto -r tfmicro.llext -nostdlib -nodefaultlibs -ffreestanding -mno-generate-flix -L . -ltfmicro_lib -lnn_hifi_lib -lc++ -lc -lm -fno-rtti -ffunction-sections -fdata-sections -lgcc -o tftest -Wl,--gc-sections -Wl,--entry=sys_comp_module_tfmicro_interface_init```
+
+```xt-objcopy --remove-section=.xt.*  tftest```
+
+This will create a llext module called ```tftest``` that will contain all the nessessary symbols. Please note the commands above are WIP and will be optimized as development continues.
+
+## Running
+
+The TFLM SOF module needs features craeted by the MFCC module as its input. This step is still in progress. The following pipeline will be used
+
+``` Mic --> MFCC --> TFLM --> Clasification ```
+
+## TODO
+
+1) Create MFCC pipeline and align with TFLM micro_speech audio feature extraction configuration.
+
+2) Support compressed output PCM with classification results.
+
+3) Load tflite models via binary kcontrol.
+
+4) Support audio processing via TFLM module.

src/audio/tfmicro/README.md

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// Copyright(c) 2025 Intel Corporation. All rights reserved.
+
+#include <stdint.h>
+#include <errno.h>
+#include <assert.h>
+#include <rtos/symbol.h>
+
+/*
+* Stubs that are needed for linkage of some applications or libraries
+* that come from porting userspace code. Anyone porting should
+* make sure that any code does not depend on working copies of these
+* reentrant functions. We will fail for any caller.
+*/
+
+struct stat;
+struct _reent;
+
+size_t _read_r(struct _reent *ptr, int fd, char *buf, size_t cnt)
+{
+  errno = -ENOTSUP;
+  return -ENOTSUP;
+}
+EXPORT_SYMBOL(_read_r);
+
+size_t _write_r(struct _reent *ptr, int fd, char *buf, size_t cnt)
+{
+  errno = -ENOTSUP;
+  return -ENOTSUP;
+}
+EXPORT_SYMBOL(_write_r);
+
+void *_sbrk_r(struct _reent *ptr, ptrdiff_t incr)
+{
+    errno = -ENOTSUP;
+    return NULL;
+}
+EXPORT_SYMBOL(_sbrk_r);
+
+int _lseek_r(struct _reent *ptr, int fd, int pos, int whence)
+{
+    errno = -ENOTSUP;
+    return -ENOTSUP;
+}
+EXPORT_SYMBOL(_lseek_r);
+
+int _kill_r(struct _reent *ptr, int pid, int sig)
+{
+    errno = -ENOTSUP;
+    return -ENOTSUP;
+}
+EXPORT_SYMBOL(_kill_r);
+
+int _getpid_r(struct _reent *ptr)
+{
+    errno = -ENOTSUP;
+    return -ENOTSUP;
+}
+EXPORT_SYMBOL(_getpid_r);
+
+int _fstat_r(struct _reent *ptr, int fd, struct stat *pstat)
+{
+    errno = -ENOTSUP;
+    return -ENOTSUP;
+}
+EXPORT_SYMBOL(_fstat_r);
+
+int _close_r(struct _reent *ptr, int fd)
+{
+    errno = -ENOTSUP;
+    return -ENOTSUP;
+}
+EXPORT_SYMBOL(_close_r);
+
+void _exit(int status)
+{
+    assert(0);
+    while(1);
+}