Test(cmocka, crossover): add unit tests for: LR4 filter, split topology

Add a cmocka-based unit test suite for the crossover audio component.
The tests target portable C code only and do not require the full SOF
component stack.

crossover_lr4_test (7 tests):
crossover_split_test (10 tests):


Enable CONFIG_COMP_CROSSOVER and CONFIG_MATH_IIR_DF2T in
unit_test_defconfig to include the new targets in the build.

Signed-off-by: Piotr Hoppe <piotr.hoppe@intel.com>

Author: piotrhoppeintel

src/arch/xtensa/configs/unit_test_defconfig

@@ -1,2 +1,4 @@
 CONFIG_METEORLAKE=y
 CONFIG_COMP_DRC=y
+CONFIG_COMP_CROSSOVER=y
+CONFIG_MATH_IIR_DF2T=y

test/cmocka/src/audio/CMakeLists.txt

@@ -25,3 +25,6 @@ endif()
 if(CONFIG_COMP_DRC)
 	add_subdirectory(drc)
 endif()
+if(CONFIG_COMP_CROSSOVER)
+	add_subdirectory(crossover)
+endif()

test/cmocka/src/audio/crossover/CMakeLists.txt

@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmocka_test(crossover_lr4_test
+	crossover_lr4_test.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_generic.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_hifi3.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_hifi4.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_hifi5.c
+	${PROJECT_SOURCE_DIR}/src/math/numbers.c
+)
+
+target_link_libraries(crossover_lr4_test PRIVATE m)
+
+# crossover_split_test: tests the split_2way / split_3way / split_4way routing
+# topology by compiling crossover_generic.c directly.  The FORMAT macros are
+# left undefined so that only the split functions (no audio_stream dependency)
+# are exercised; audio_stream_copy is stubbed inside crossover_split_test.c.
+
+add_compile_options(-DUNIT_TEST)
+
+cmocka_test(crossover_split_test
+	crossover_split_test.c
+	${PROJECT_SOURCE_DIR}/src/audio/crossover/crossover_generic.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_generic.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_hifi3.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_hifi4.c
+	${PROJECT_SOURCE_DIR}/src/math/iir_df1_hifi5.c
+	${PROJECT_SOURCE_DIR}/src/math/numbers.c
+	${PROJECT_SOURCE_DIR}/src/audio/audio_stream.c
+)
+
+target_include_directories(crossover_split_test PRIVATE
+	${PROJECT_SOURCE_DIR}/src/audio/crossover
+)
+
+target_link_libraries(crossover_split_test PRIVATE m)