audio: make clock control optional in SOF Zephyr builds

Mark the few places in generic SOF code where SOF clock control
interface is used. These cases are few as most usage has traditionally
been in XTOS drivers and platform code. In Zephyr builds these are
not used, making the clock interface mostly unnecessary.

The one bigger exception is CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL feature
for dynamically adjusting the DSP clock frequency based on IPC
messages and audio pipeline configuration. This is an optional
feature not used by all targets, so the requirement to have a clock
abstraction implemented, should also be optional.

Remaining uses are for IPC4 base firmware attributes and some
informational use in logging. None of these are e.g. required by SOF
Linux driver for any essential functionality, so can be disabled
without side-effects.

As the rtos/clk.h interfaces are still used in many places in
platform code, this patch adds a new transition tool in form
of CONFIG_SOF_ZEPHYR_NO_SOF_CLOCK Kconfig option. This allows
to incrementally transition targets to not use the clock
framework.

In longer term, the remaining uses will be transitioned to use
Zephyr clock-control.h directly

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

src/audio/base_fw.c

@@ -58,13 +58,15 @@ static int basefw_config(uint32_t *data_offset, char *data)
 	tuple = tlv_next(tuple);
 	tlv_value_uint32_set(tuple, IPC4_MEMORY_RECLAIMED_FW_CFG, 1);
 
+#ifndef CONFIG_SOF_ZEPHYR_NO_SOF_CLOCK
 	tuple = tlv_next(tuple);
 	tlv_value_uint32_set(tuple, IPC4_FAST_CLOCK_FREQ_HZ_FW_CFG, CLK_MAX_CPU_HZ);
 
 	tuple = tlv_next(tuple);
 	tlv_value_uint32_set(tuple,
 			     IPC4_SLOW_CLOCK_FREQ_HZ_FW_CFG,
 			     clock_get_freq(CPU_LOWEST_FREQ_IDX));
+#endif
 
 	tuple = tlv_next(tuple);
 	tlv_value_uint32_set(tuple, IPC4_DL_MAILBOX_BYTES_FW_CFG, MAILBOX_HOSTBOX_SIZE);
@@ -220,17 +222,21 @@ static int basefw_register_kcps(bool first_block,
 	if (!(first_block && last_block))
 		return IPC4_ERROR_INVALID_PARAM;
 
+#if CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL
 	/* value of kcps to request on core 0. Can be negative */
 	if (core_kcps_adjust(0, *(int32_t *)data))
 		return IPC4_ERROR_INVALID_PARAM;
+#endif
 
 	return IPC4_SUCCESS;
 }
 
 static int basefw_kcps_allocation_request(struct ipc4_resource_kcps *request)
 {
+#if CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL
 	if (core_kcps_adjust(request->core_id, request->kcps))
 		return IPC4_ERROR_INVALID_PARAM;
+#endif
 
 	return IPC4_SUCCESS;
 }
@@ -259,6 +265,7 @@ static int basefw_resource_allocation_request(bool first_block,
 
 static int basefw_power_state_info_get(uint32_t *data_offset, char *data)
 {
+#if CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL
 	struct sof_tlv *tuple = (struct sof_tlv *)data;
 	uint32_t core_kcps[CONFIG_CORE_COUNT] = {0};
 	int core_id;
@@ -275,6 +282,9 @@ static int basefw_power_state_info_get(uint32_t *data_offset, char *data)
 	tuple = tlv_next(tuple);
 	*data_offset = (int)((char *)tuple - data);
 	return IPC4_SUCCESS;
+#else
+	return IPC4_UNAVAILABLE;
+#endif
 }
 
 static int basefw_libraries_info_get(uint32_t *data_offset, char *data)

src/audio/pipeline/pipeline-graph.c

@@ -282,7 +282,7 @@ int pipeline_complete(struct pipeline *p, struct comp_dev *source,
 		.comp_data = &data,
 	};
 
-#if !UNIT_TEST && !CONFIG_LIBRARY
+#if !UNIT_TEST && !CONFIG_LIBRARY && CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL
 	int __maybe_unused freq = clock_get_freq(cpu_get_id());
 #else
 	int __maybe_unused freq = 0;

zephyr/CMakeLists.txt

@@ -490,9 +490,7 @@ zephyr_library_sources(
 	${SOF_MATH_PATH}/exp_fcn_hifi.c
 
 	# SOF library - parts to transition to Zephyr over time
-	${SOF_LIB_PATH}/clk.c
 	${SOF_LIB_PATH}/notifier.c
-	${SOF_LIB_PATH}/cpu-clk-manager.c
 	${SOF_LIB_PATH}/dma.c
 	${SOF_LIB_PATH}/dai.c
 
@@ -530,6 +528,14 @@ zephyr_library_sources(
 	lib.c
 )
 
+if(NOT CONFIG_SOF_ZEPHYR_NO_SOF_CLOCK)
+	zephyr_library_sources(${SOF_LIB_PATH}/clk.c)
+endif()
+
+zephyr_library_sources_ifdef(CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL
+	${SOF_LIB_PATH}/cpu-clk-manager.c
+)
+
 # Optional math utility
 zephyr_library_sources_ifdef(CONFIG_MATH_LUT_SINE_FIXED
 	${SOF_MATH_PATH}/lut_trig.c

zephyr/Kconfig

@@ -76,4 +76,10 @@ config SOF_BOOT_TEST
 	  initialized. After that SOF will continue running and be usable as
 	  usual.
 
+config SOF_ZEPHYR_NO_SOF_CLOCK
+	bool
+	help
+	  Do not use SOF clk.h interface to set the DSP clock frequency.
+	  Requires implementation of platform/lib/clk.h.
+
 endif

zephyr/include/rtos/clk.h

@@ -6,9 +6,10 @@
 #ifndef __ZEPHYR_RTOS_CLK_H__
 #define __ZEPHYR_RTOS_CLK_H__
 
+#ifndef CONFIG_SOF_ZEPHYR_NO_SOF_CLOCK
+
 #include <zephyr/kernel.h>
 
-/* TODO remove once drivers upstream */
 #define __SOF_LIB_CLK_H__
 #include <platform/lib/clk.h>
 
@@ -77,4 +78,6 @@ static inline struct clock_info *clocks_get(void)
 	return sof_get()->clocks;
 }
 
+#endif /* CONFIG_SOF_ZEPHYR_NO_SOF_CLOCK */
+
 #endif /* __ZEPHYR_RTOS_CLK_H__ */