pipeline: introduce declarative static topology definition and loader

Add support for declarative static audio pipelines in Sound Open Firmware.
In microcontroller, hostless, and standalone embedded environments (such
as ESP32-P4/S3/C6, PJRC Teensy 4.1, Nordic nRF54, RP2350, smart speakers,
and audio bridges), there is no dynamic IPC host driver (Linux ALSA/SoundWire
or Windows) to build topologies at runtime.

This introduces:
1. Declarative topology structures, capability flags, and constructor
   macros in <sof/audio/pipeline/static_pipeline.h> with full Doxygen
   docblocks covering all structures, fields, enums, macros, and public
   APIs. Complete sample rate masks (8k through 384k) aligned with
   SOF_RATE_* and frame format masks aligned with enum sof_ipc_frame.
2. Ops-driven static module architecture: generic headers and loader
   engine are 100% decoupled from individual audio processing components.
   Audio processing modules define and register their own operations
   (struct sof_static_module_ops) providing .create, .apply_volume,
   .apply_switch, and .apply_enum callbacks directly in their own source
   files (SRC, ASRC, Volume/Gain, Level Multiplier, Selector, EQ IIR,
   DRC, and TDFB) using DECLARE_STATIC_MODULE_OPS().
3. Generic module operations registry and base IPC4 config synthesizer
   in static_pipeline_modules.c: completely generic infrastructure for
   ops registration, lookup with error logging, base configuration
   synthesis with macros for IPC4 channel maps, and default fallback
   component instantiation.
4. Concise, generic constructor macros (SOF_STATIC_MODULE,
   SOF_STATIC_MODULE_RATE_CONV, SOF_STATIC_ENDPOINT_DAI, and
   SOF_STATIC_ENDPOINT_USB) allowing clean, compact topology definitions
   for any audio processing module and DAI endpoint.
5. Modular IPC configuration and base config synthesizer: synthesizes
   standard IPC4 base module configurations (struct ipc4_base_module_cfg)
   on behalf of the absent host, calculating input and output buffer sizes
   (IBS/OBS) dynamically from component capabilities and pipeline periods.
6. Dynamic multi-rate, multi-channel, and format negotiation: eliminates
   hardcoded sample rates and channel counts in buffer initialization and
   pipeline/component prepare, supporting sample rate converters (SRC/ASRC),
   up/down mixers, and format conversions with per-buffer rate/channel inheritance.
7. Generic static topology loader engine in static_pipeline_loader.c
   to parse and instantiate native SOF components, buffers, routes,
   and kcontrols directly at boot.
8. Component preparation and parameter negotiation to ensure all
   processing modules reach ready state prior to streaming.
9. Direct pipeline start, stop, and trigger control with separate
   start/stop execution paths (sof_static_pipeline_start,
   sof_static_pipeline_stop), strict error checking preventing triggers
   on prepare failures, state validation, and copy task management.
10. Decoupled custom kcontrol callback handler to support platform-
    and board-specific controls without polluting core audio modules.
11. CONFIG_STATIC_PIPELINE Kconfig option and CMakeLists.txt integration.
12. Comprehensive developer documentation, architecture overview, and
    step-by-step tutorial with multi-rate SRC examples in
    src/audio/pipeline/README.md.

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

Author: lrgirdwo

src/audio/Kconfig

@@ -51,6 +51,16 @@ config HOST_DMA_IPC_POSITION_UPDATES
 	  by sending an IPC message whenever one period of audio is transferred.
 	  Most platforms provide more efficient ways to query the DMA status.
 
+config STATIC_PIPELINE
+	bool "Declarative Static Audio Pipeline Loader"
+	default n
+	help
+	  Enable support for declarative static audio pipelines in Sound
+	  Open Firmware. This provides a compile-time and runtime loader
+	  engine for hostless, microcontroller, and standalone embedded
+	  targets that do not rely on dynamic IPC topology messages from
+	  a host operating system.
+
 config COMP_CHAIN_DMA
 	  bool "Chain DMA component"
 	  depends on IPC_MAJOR_4

src/audio/asrc/asrc.c

@@ -846,4 +846,39 @@ SOF_LLEXT_BUILDINFO;
 DECLARE_MODULE_ADAPTER(asrc_interface, ASRC_UUID, asrc_tr);
 SOF_MODULE_INIT(asrc, sys_comp_module_asrc_interface_init);
 
+#if CONFIG_STATIC_PIPELINE
+#include <sof/audio/pipeline/static_pipeline.h>
+
+#if CONFIG_IPC_MAJOR_4
+#include "asrc_ipc4.h"
+
+static struct comp_dev *asrc_static_create(const struct comp_driver *drv,
+					   struct comp_ipc_config *cfg,
+					   const struct sof_static_comp *cdesc,
+					   uint32_t period_us)
+{
+	struct ipc4_asrc_module_cfg asrc_cfg;
+
+	memset(&asrc_cfg, 0, sizeof(asrc_cfg));
+	sof_static_init_base_cfg(&asrc_cfg.base, cdesc, period_us);
+	asrc_cfg.out_freq = (enum ipc4_sampling_frequency)(cdesc->caps.sink_rate ?
+							   cdesc->caps.sink_rate :
+							   cdesc->caps.default_rate);
+
+	struct ipc_config_process spec = {
+		.size = sizeof(asrc_cfg),
+		.data = (const uint8_t *)&asrc_cfg,
+	};
+	return drv->ops.create(drv, cfg, &spec);
+}
+
+static struct sof_static_module_ops asrc_static_ops = {
+	.uuid = &ASRC_UUID,
+	.create = asrc_static_create,
+};
+
+DECLARE_STATIC_MODULE_OPS(asrc, &asrc_static_ops);
+#endif /* CONFIG_IPC_MAJOR_4 */
+#endif /* CONFIG_STATIC_PIPELINE */
+
 #endif

src/audio/drc/drc.c

@@ -481,4 +481,30 @@ SOF_LLEXT_BUILDINFO;
 DECLARE_MODULE_ADAPTER(drc_interface, drc_uuid, drc_tr);
 SOF_MODULE_INIT(drc, sys_comp_module_drc_interface_init);
 
+#if CONFIG_STATIC_PIPELINE
+#include <sof/audio/pipeline/static_pipeline.h>
+
+static int drc_static_apply_switch(struct comp_dev *dev, uint32_t channels, int32_t val)
+{
+	struct processing_module *mod = comp_mod(dev);
+
+	if (!mod)
+		return -EINVAL;
+
+	struct drc_comp_data *cd = module_get_private_data(mod);
+
+	if (cd)
+		cd->enable_switch = (val != 0);
+
+	return 0;
+}
+
+static struct sof_static_module_ops drc_static_ops = {
+	.uuid = &drc_uuid,
+	.apply_switch = drc_static_apply_switch,
+};
+
+DECLARE_STATIC_MODULE_OPS(drc, &drc_static_ops);
+#endif /* CONFIG_STATIC_PIPELINE */
+
 #endif

src/audio/eq_iir/eq_iir.c

@@ -258,4 +258,43 @@ DECLARE_TR_CTX(eq_iir_tr, SOF_UUID(eq_iir_uuid), LOG_LEVEL_INFO);
 DECLARE_MODULE_ADAPTER(eq_iir_interface, eq_iir_uuid, eq_iir_tr);
 SOF_MODULE_INIT(eq_iir, sys_comp_module_eq_iir_interface_init);
 
+#if CONFIG_STATIC_PIPELINE
+#include <sof/audio/pipeline/static_pipeline.h>
+
+static int eq_iir_static_apply_switch(struct comp_dev *dev, uint32_t channels, int32_t val)
+{
+	struct processing_module *mod = comp_mod(dev);
+
+	if (!mod)
+		return -EINVAL;
+
+	struct comp_data *cd = module_get_private_data(mod);
+
+	if (cd) {
+		if (val == 0) {
+			cd->eq_iir_func = eq_iir_pass;
+		} else if (cd->iir_delay_size) {
+#if CONFIG_FORMAT_FLOAT
+			struct comp_buffer *sourceb = comp_dev_get_first_data_producer(dev);
+
+			if (sourceb && audio_stream_get_frm_fmt(&sourceb->stream) == SOF_IPC_FRAME_FLOAT)
+				cd->eq_iir_func = eq_iir_float_default;
+			else
+				cd->eq_iir_func = eq_iir_s16_default;
+#else
+			cd->eq_iir_func = eq_iir_s16_default;
+#endif
+		}
+	}
+	return 0;
+}
+
+static struct sof_static_module_ops eq_iir_static_ops = {
+	.uuid = &eq_iir_uuid,
+	.apply_switch = eq_iir_static_apply_switch,
+};
+
+DECLARE_STATIC_MODULE_OPS(eq_iir, &eq_iir_static_ops);
+#endif /* CONFIG_STATIC_PIPELINE */
+
 #endif

src/audio/level_multiplier/level_multiplier.c

@@ -204,4 +204,46 @@ DECLARE_TR_CTX(level_multiplier_tr, SOF_UUID(level_multiplier_uuid), LOG_LEVEL_I
 DECLARE_MODULE_ADAPTER(level_multiplier_interface, level_multiplier_uuid, level_multiplier_tr);
 SOF_MODULE_INIT(level_multiplier, sys_comp_module_level_multiplier_interface_init);
 
+#if CONFIG_STATIC_PIPELINE
+#include <sof/audio/pipeline/static_pipeline.h>
+
+static int lm_static_apply_volume(struct comp_dev *dev, uint32_t channels, int32_t val)
+{
+	struct processing_module *mod = comp_mod(dev);
+
+	if (!mod)
+		return -EINVAL;
+
+	struct level_multiplier_comp_data *cd = module_get_private_data(mod);
+
+	if (cd)
+		cd->gain = val;
+
+	return 0;
+}
+
+static int lm_static_apply_switch(struct comp_dev *dev, uint32_t channels, int32_t val)
+{
+	struct processing_module *mod = comp_mod(dev);
+
+	if (!mod)
+		return -EINVAL;
+
+	struct level_multiplier_comp_data *cd = module_get_private_data(mod);
+
+	if (cd)
+		cd->gain = (val == 0) ? 0 : LEVEL_MULTIPLIER_GAIN_ONE;
+
+	return 0;
+}
+
+static struct sof_static_module_ops lm_static_ops = {
+	.uuid = &level_multiplier_uuid,
+	.apply_volume = lm_static_apply_volume,
+	.apply_switch = lm_static_apply_switch,
+};
+
+DECLARE_STATIC_MODULE_OPS(level_multiplier, &lm_static_ops);
+#endif /* CONFIG_STATIC_PIPELINE */
+
 #endif

src/audio/pipeline/CMakeLists.txt

@@ -7,3 +7,8 @@ add_local_sources(sof
   pipeline-xrun.c
   pipeline-schedule.c
 )
+
+add_local_sources_ifdef(CONFIG_STATIC_PIPELINE sof
+  static_pipeline_loader.c
+  static_pipeline_modules.c
+)