WIP: nordic: add nRF54L15 and nRF54LM20 platform support and full-duplex I2S loopback by lgirdwood · Pull Request #11224 · thesofproject/sof

lgirdwood · 2026-09-22T21:00:44Z

Summary

This draft PR introduces Sound Open Firmware (SOF) platform support for Nordic Semiconductor nRF54L Series development boards (ARM Cortex-M33 with FPU @ 128 MHz):

Nordic nRF54LM20-DK (PCA10184): High-speed USB UAC2 ingress and hardware I2S/TDM Master Tx/Rx.
Nordic nRF54L15-DK (PCA10156): Hardware I2S20 Slave Full-Duplex Echo with parametric EQ and DRC processing.

Companion Zephyr driver changes are in lgirdwood/zephyr#2 on branch feature/nordic-dai-port.

Key Changes

Nordic Platform Support (src/platform/nordic/):
- Added platform definitions, interrupt registration, mailbox stubs, and clocks for nRF54L15 and nRF54LM20.
- Added board configurations and devicetree overlays for nrf54l15dk_nrf54l15_cpuapp and nrf54lm20dk_nrf54lm20b_cpuapp.
I2S Hardware Audio Driver Component (src/audio/i2s_audio.c):
- Implemented SOF host endpoint for Zephyr I2S subsystem supporting both i2s_nrfx (nRF54L15) and i2s_nrf_tdm (nRF54LM20).
- Real-time periodic telemetry reporting frame rates and buffer overruns/underruns.
Static Audio Pipeline Topologies:
- nRF54LM20 (nrf54lm20_pipeline_def.c):
  - Pipeline 1: USB_PB $\to$ VOL_PB $\to$ EQ_PB $\to$ DRC_PB $\to$ I2S_TX (TDM Master Tx)
  - Pipeline 2: I2S_RX (TDM Master Rx) $\to$ LEVEL_RX $\to$ USB_CAP
- nRF54L15 (nrf54l15_pipeline_def.c):
  - Pipeline 1: I2S_RX (I2S20 Slave Rx) $\to$ VOL_PB $\to$ EQ_PB $\to$ DRC_PB $\to$ I2S_TX (I2S20 Slave Tx) full-duplex loopback.
nRF54L15 Interconnect Pin Multiplexing:
- Routed i2s20 peripheral to GPIO Port 1 pins (P1.11 SCK, P1.12 LRCK, P1.09 SDIN, P1.08 SDOUT) to comply with nRF54L15 peripheral domain interconnect silicon constraints.
Static Pipeline Loader (static_pipeline_loader.c):
- Enhanced sof_static_pipeline_trigger() to resolve pipe->sink_comp when triggering capture pipelines where scheduler component is not at the source.

Live Hardware Verification

Verified with physical jumper cables between nRF54LM20-DK Header P3 (Master) and nRF54L15-DK Header P1 (Slave):

BCLK: LM20 P1.23 $\to$ L15 P1.11
LRCK / FSYNC: LM20 P1.24 $\to$ L15 P1.12
SDOUT $\to$ SDIN: LM20 P1.30 $\to$ L15 P1.09
SDIN $\leftarrow$ SDOUT: LM20 P1.31 $\leftarrow$ L15 P1.08
GND: Header P3 GND $\to$ Header P1 GND

Both boards continuously stream full-duplex 48 kHz stereo 16-bit PCM at exactly 48,000 frames/second with 0 overruns:

LM20-DK: Streamed $>2,064,000$ frames TX/RX at $+48,000$ frames/s.
L15-DK: Streamed $>5,088,000$ frames TX/RX at $+48,000$ frames/s.

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Copilot review overview

5 open issues

The Teensy vendor requests implement arbitrary memory read/write over USB control transfers… · New
i2s_audio allocates its private data with SOF_MEM_FLAG_USER. This component is registered as… · New
The TX priming loop ignores the return value of i2s_write(). In Zephyr's I2S API, on write… · New
If i2s_read() returns a non-NULL rx_block but rx_size is smaller than I2S_BLOCK_SIZE (or if… · New
ring.count is modified under k_spin_lock(&ring->lock) in other functions, but here it is read… · New

What changed in this PR

This draft PR adds Zephyr-only SOF support for Nordic nRF54L series boards, including new platform bring-up pieces, static pipeline topologies, and new host-like components for USB/I2S/BT audio bridging.

Changes:

Added Nordic platform layer (clock init, mailbox definitions, platform init) and board-specific static pipeline topologies for nRF54L15 and nRF54LM20.
Introduced new “host endpoint” style audio components: usb_audio, i2s_audio, bt_audio plus a Bluetooth service helper and a Nordic-focused static pipeline controller.
Expanded Zephyr build integration (CMake/Kconfig/syscall guards), UUID registry entries, and minor runtime fixes in existing modules/DAI code.

File	Description
zephyr/lib/alloc.c	Adds Nordic heap sizing/allocation path for Zephyr builds.
zephyr/include/sof/lib/cpu.h	Gates syscall declarations on `CONFIG_USERSPACE` for full Zephyr app builds.
zephyr/include/rtos/cache.h	Adjusts default cache line size logic to include Nordic.
zephyr/CMakeLists.txt	Adds Nordic platform selection/build wiring and generated include dir.
uuid-registry.txt	Adds UUID registry entries for new audio components.
src/platform/nordic/platform.c	Implements Nordic platform init + IPC/mailbox boot-ready handling.
src/platform/nordic/nrf54lm20_pipeline_def.c	Adds static topology for LM20 (USB↔I2S + capture loop).
src/platform/nordic/nrf54l15_pipeline_def.c	Adds static topology for L15 full-duplex I2S echo.
src/platform/nordic/lib/clk.c	Adds minimal clock table/init for Nordic.
src/platform/nordic/include/platform/trace/trace.h	Adds Nordic platform trace header stub.
src/platform/nordic/include/platform/platform.h	Adds Nordic platform constants and limits.
src/platform/nordic/include/platform/lib/pm_runtime.h	Adds Nordic PM runtime header stub.
src/platform/nordic/include/platform/lib/memory.h	Adds Nordic heap sizing + cache alignment macros.
src/platform/nordic/include/platform/lib/mailbox.h	Adds mailbox layout and stubbed SW reg accessors.
src/platform/nordic/include/platform/lib/dma.h	Adds Nordic DMA header stub (0 DMACs).
src/platform/nordic/include/platform/lib/dai.h	Adds Nordic DAI header including Zephyr DAI glue.
src/platform/nordic/include/platform/lib/clk.h	Adds Nordic clock constants + init prototype.
src/platform/nordic/include/platform/drivers/interrupt.h	Adds Nordic interrupt header stub.
src/platform/Kconfig	Adds `PLATFORM_NORDIC` + nRF54L15/nRF54LM20 choice.
src/include/user/debug_stream_slot.h	Adds non-userspace fallback mapping for syscall symbol.
src/include/sof/schedule/ll_schedule_domain.h	Gates syscall API on `CONFIG_USERSPACE` for full Zephyr app.
src/include/sof/schedule/dp_schedule.h	Adds non-userspace fallbacks and gates syscalls on `CONFIG_USERSPACE`.
src/include/sof/lib_manager.h	Gates syscall API on `CONFIG_USERSPACE` for full Zephyr app.
src/include/sof/lib/vregion.h	Only includes Zephyr syscall header when userspace is enabled.
src/include/sof/lib/dai-zephyr.h	Adds non-userspace fallbacks for Zephyr DAI device accessors.
src/include/sof/ipc/msg.h	Gates IPC-related syscalls on `CONFIG_USERSPACE` for full Zephyr app.
src/include/sof/ipc/ipc_reply.h	Gates reply syscall on `CONFIG_USERSPACE` for full Zephyr app.
src/include/sof/audio/usb_audio.h	Adds public header for USB audio component bridge API.
src/include/sof/audio/pipeline/sof_static_pipeline.h	Adds higher-level static pipeline control/status API.
src/include/sof/audio/module_adapter/module/generic.h	Gates module syscalls on `CONFIG_USERSPACE` in full Zephyr app.
src/include/sof/audio/i2s_audio.h	Adds public header for I2S audio component stats API.
src/include/sof/audio/bt_service.h	Adds public BT service control/status API.
src/include/sof/audio/bt_audio.h	Adds public BT audio component bridge API.
src/include/ipc4/notification.h	Gates IPC4 notification syscalls on `CONFIG_USERSPACE`.
src/include/ipc4/handler.h	Gates IPC4 handler syscalls on `CONFIG_USERSPACE`.
src/audio/usb_audio.c	Implements USB audio ring-buffer bridge component (`usb_audio`).
src/audio/pipeline/sof_static_pipeline.c	Adds Nordic-focused static pipeline orchestration + UAC2 glue.
src/audio/pipeline/CMakeLists.txt	Builds `sof_static_pipeline.c` for Nordic.
src/audio/module_adapter/module_adapter_ipc4.c	Initializes module sinks/sources if missing before prepare.
src/audio/i2s_audio.c	Implements Zephyr I2S bridge component (`i2s_audio`).
src/audio/drc/drc_riscv.c	Switches byte count/channel parameter types to `size_t`/`unsigned`.
src/audio/drc/drc_log.c	Forces DRC module registration reference when built-in.
src/audio/drc/drc_arm.c	Switches byte count/channel parameter types to `size_t`/`unsigned`.
src/audio/dai-zephyr.c	Nordic-specific DAI reset/trigger behavior adjustments.
src/audio/bt_service.c	Adds BT service thread + Nordic LM20/L15 connect/scan logic.
src/audio/bt_audio.c	Implements BT audio ring-buffer bridge component (`bt_audio`).
src/audio/Kconfig	Adds Kconfigs for new USB/BT/I2S bridge components.
src/audio/CMakeLists.txt	Adds build rules for new audio components.
scripts/cmake/misc.cmake	Treats full Zephyr app builds as “Zephyr” in helper macro.
app/src/usbd_init.c	Adds USB device stack init helper (with Teensy vendor requests).
app/src/sample_usbd.h	Adds sample USBD helper header.
app/src/main.c	Initializes UAC2 ops, USB stack, BT service, and static pipelines for Nordic.
app/boards/nrf54lm20dk_nrf54lm20b_cpuapp.overlay	Adds LM20 UAC2 + TDM pinmux overlay and alias for I2S node.
app/boards/nrf54lm20dk_nrf54lm20b_cpuapp.conf	Adds LM20 feature set config (UAC2 HS, TDM, modules).
app/boards/nrf54l15dk_nrf54l15_cpuapp.overlay	Adds L15 I2S20 pinmux overlay and alias for I2S node.
app/boards/nrf54l15dk_nrf54l15_cpuapp.conf	Adds L15 feature set config (I2S NRFX slave, modules).
app/Kconfig	Pulls in sample USBD Kconfig and rsource Zephyr Kconfig when needed.
app/CMakeLists.txt	Links SOF libraries into the Zephyr app and adds USBD init source.
Kconfig.sof	Always includes Zephyr log Kconfig rather than gating on module build.

_{Review effort: Lite}

lgirdwood · 2026-11-10T22:56:38Z

+static struct net_buf *teensy_peek_to_host(const struct usbd_context *const ctx,
+					   const struct usb_setup_packet *const setup)
+{
+	uint32_t addr = (setup->wIndex << 16) | setup->wValue;
+	uint16_t len = MIN(setup->wLength, 64);
+	if (!len) return NULL;
+	struct net_buf *buf = usbd_ep_ctrl_data_in_alloc(ctx, len);
+	if (!buf) return NULL;
+	net_buf_add_mem(buf, (const void *)addr, len);
+	return buf;
+}
+
+static int teensy_poke_to_dev(const struct usbd_context *const ctx,
+			      const struct usb_setup_packet *const setup,
+			      const struct net_buf *const buf)
+{
+	ARG_UNUSED(ctx);
+	uint32_t addr = (setup->wIndex << 16) | setup->wValue;
+	if (buf && buf->len > 0) {
+		if (setup->wLength == 1) {
+			*(volatile uint8_t *)addr = buf->data[0];
+		} else if (setup->wLength == 2) {
+			uint16_t val;
+			memcpy(&val, buf->data, 2);
+			*(volatile uint16_t *)addr = val;
+		} else if (setup->wLength == 4) {
+			uint32_t val;
+			memcpy(&val, buf->data, 4);
+			*(volatile uint32_t *)addr = val;
+		}
+	}
+	return 0;
+}


Removed all Teensy and ESP32 vendor requests, peek/poke routines, and hardware diagnostics entirely from usbd_init.c, eliminating arbitrary memory access risks and keeping the USB stack standard.

lgirdwood · 2026-11-10T22:56:42Z

+
+	dev->ipc_config = *config;
+
+	iad = rzalloc(SOF_MEM_FLAG_USER, sizeof(*iad));


Fixed to allocate with SOF_MEM_FLAG_KERNEL consistent with kernel context and other host components.

lgirdwood · 2026-11-10T22:56:46Z

+				void *block;
+				for (int i = 0; i < 8; i++) {
+					if (k_mem_slab_alloc(&i2s_tx_slab, &block, K_NO_WAIT) == 0) {
+						memset(block, 0, I2S_BLOCK_SIZE);
+						i2s_write(s_i2s_dev, block, I2S_BLOCK_SIZE);
+					}
+				}


Fixed: now checks i2s_write() return value during TX priming and frees the slab buffer on write failure to prevent memory leaks.

lgirdwood · 2026-11-10T22:56:49Z

+				}
+				k_mem_slab_free(&i2s_rx_slab, rx_block);
+				s_i2s_stats.rx_frames += frames_to_copy;
+			} else {


Fixed: ensures rx_block is released back to i2s_rx_slab on all error and size-mismatch paths.

lgirdwood · 2026-11-10T22:56:53Z

+	if (!g_capture_data || !g_capture_data->active || !g_capture_data->started) {
+		return false;
+	}
+	return g_capture_data->ring.count >= bytes;


Fixed: usb_audio_has_capture_data() now acquires ring->lock before inspecting ring->count to prevent race conditions on SMP/preemption.

lgirdwood

This needs to be split into zephyr patches and sof patches. Each per feature. The zephyr patches can go on my fork and be referred via a temp west patch

lgirdwood · 2026-11-10T16:14:22Z

 				 const struct sof_drc_params *p,
-				 int nbyte,
-				 int nch)
+				 size_t nbyte,


this needs to be a separate patch

Split into a dedicated commit: audio: drc: align drc_arm and drc_riscv parameter types with drc_algorithm.h.

lgirdwood · 2026-11-10T16:14:41Z

 EXPORT_SYMBOL(log_dynamic_drc);
 #endif
+
+#if !CONFIG_COMP_DRC_MODULE


a separate patch.

Reverted this change; the __used reference was a temporary workaround that broke non-Zephyr host testbench builds. DRC symbols are properly linked without it.

lgirdwood · 2026-11-10T16:14:59Z

 {
 	struct processing_module *mod = comp_mod(dev);

+	if (!mod->num_of_sources && !mod->num_of_sinks)


should be its own patch

Split into a dedicated commit: audio: module_adapter: initialize sinks and sources in prepare if unpopulated.

lgirdwood · 2026-11-10T16:21:53Z

@@ -0,0 +1,805 @@
+// SPDX-License-Identifier: BSD-3-Clause


we should be reusing the existing static pipeline logic.

Refactored to directly reuse the upstream static_pipeline_loader.c and static_pipeline_uac2.c infrastructure (sof_static_topology_init, sof_static_pipeline_trigger, sof_static_kcontrol_set_by_uac2, etc.). Purged all non-Nordic (ESP32-P4 and Teensy 4.1) hardware manipulation and register code.

lgirdwood · 2026-11-10T16:27:33Z

+
+	if (g_status.playback_active || g_status.capture_active) {
+		s_sof_diag_cnt++;
+#if defined(CONFIG_PLATFORM_ESP32P4)


this looks like it should be under LOG_DBG ?

Fixed: replaced periodic diagnostics with LOG_DBG and removed the ESP32 register dump entirely.

…rithm.h Update drc_update_detector_average and drc_compress_output in drc_arm.c and drc_riscv.c to take size_t nbyte and unsigned int nch, matching the prototypes declared in drc_algorithm.h. Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

…opulated In static audio pipeline configurations where module sources and sinks have not yet been enumerated via dynamic IPC4 binding commands, trigger module_adapter_update_sinks_sources() during module_adapter_sink_src_prepare() if both num_of_sources and num_of_sinks are zero. Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

…ication support - Guard Zephyr syscall headers and prototypes with CONFIG_USERSPACE checks in SOF headers so non-userspace platforms build without stub generation. - Fix Doxygen group closing tag in dai-zephyr.h to ensure valid group scope independent of CONFIG_USERSPACE definition. - Support CONFIG_SOF_FULL_ZEPHYR_APPLICATION in is_zephyr() macro. - Hoist version and uuid registry target generation before subdirectory processing. - Add UUID entries for usb_audio and bt_audio in uuid-registry.txt. - Define heapmem sizing for CONFIG_PLATFORM_NORDIC. Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

Temporarily point the Zephyr project remote to https://github.com/lgirdwood/zephyr at revision fcf26c58845d3cf24348d273e119879a699e4fc9 (branch feature/nordic-dai-port) which contains the i2s_nrfx and i2s_nrf_tdm DAI driver enhancements for Nordic nRF54L Series boards while upstream Zephyr PR reviews are pending. Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

- Add USB Audio Class 2 (UAC2) host endpoint component (usb_audio.c) with spinlock-protected buffer count checking. - Add Bluetooth LE Audio streaming endpoint and service (bt_audio.c, bt_service.c). - Add Zephyr I2S host endpoint supporting full-duplex PCM streaming (i2s_audio.c), allocating private context with SOF_MEM_FLAG_KERNEL, error handling on TX priming buffer submission with slab release, and RX slab free on error/mismatch. - Add static pipeline runner and runtime control dispatcher (sof_static_pipeline.c) reusing upstream static pipeline topology and UAC2 kcontrol APIs. Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

…l-duplex I2S loopback Add full platform support and static audio topologies for Nordic nRF54L15 (PCA10156) and nRF54LM20 (PCA10184) running on Zephyr RTOS: - src/platform/nordic: platform boot, clock tree (128 MHz), mailbox structures, Zephyr timer-based Low-Latency scheduler domain (zephyr_domain_init). - static topologies: * nRF54LM20: Pipeline 1 (USB_PB -> VOL -> EQ -> DRC -> I2S_TX) master playback, Pipeline 2 (I2S_RX -> LEVEL -> USB_CAP) master loopback capture. * nRF54L15: Pipeline 1 (I2S_RX -> VOL -> EQ -> DRC -> I2S_TX) slave full-duplex echo. - app/boards: devicetree overlays and Kconfig configurations for: * nrf54l15dk_nrf54l15_cpuapp: i2s20 slave interconnect mapped to Port 1 (P1.11 BCLK, P1.12 LRCK, P1.09 SDIN, P1.08 SDOUT). * nrf54lm20dk_nrf54lm20b_cpuapp: High-speed USB UAC2 device and i2s_nrf_tdm master (P1.23 BCLK, P1.24 FSYNC, P1.30 SDOUT, P1.31 SDIN). - app/src/usbd_init.c: Standard USB UAC2 device stack initialization without non-standard peek/poke vendor requests. Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

lgirdwood · 2026-11-10T22:57:09Z

The PR has been reorganized according to review feedback:

Zephyr / SOF Separation:
- Zephyr DAI and peripheral driver changes are maintained on lgirdwood/zephyr on branch feature/nordic-dai-port (commit fcf26c58845d3cf24348d273e119879a699e4fc9).
- A dedicated temporary manifest patch is included in this series (west: manifest: temporarily reference Zephyr DAI port for Nordic) pointing to that fork until Zephyr upstream merges.
Clean Per-Feature Patch Series:
The SOF branch is rebased on latest main and cleanly split into 6 focused commits:
- audio: drc: align drc_arm and drc_riscv parameter types with drc_algorithm.h
- audio: module_adapter: initialize sinks and sources in prepare if unpopulated
- zephyr: build: guard userspace syscall declarations and add full application support
- west: manifest: temporarily reference Zephyr DAI port for Nordic
- audio: host: add USB, Bluetooth, and I2S static pipeline endpoints
- platform: nordic: add nRF54L15 and nRF54LM20 platform support and full-duplex I2S loopback
Addressed All Review Comments:
- DRC: Fixed parameter types in drc_arm.c and drc_riscv.c to match drc_algorithm.h (size_t nbyte, unsigned int nch). Reverted drc_log.c hack to origin/main (fixes host testbench).
- Doxygen / Headers: Fixed Doxygen group closure error in dai-zephyr.h by keeping /** @}*/ outside CONFIG_USERSPACE.
- Static Pipeline & USB Cleanup: Purged all ESP32/Teensy hardware registers, clock switching code, and peek/poke vendor requests from sof_static_pipeline.c and usbd_init.c. Refactored pipeline management to leverage upstream static_pipeline_loader APIs.
- I2S Audio: Changed i2s_audio allocation to SOF_MEM_FLAG_KERNEL, added error handling and slab free on i2s_write() during TX priming, and guaranteed rx_block slab release on all error and size-mismatch paths.
- USB Audio: Added k_spin_lock protection to usb_audio_has_capture_data() to prevent races on SMP/preemption.
- Zephyr Module Integration: Used EXTRA_ZEPHYR_MODULES in app/CMakeLists.txt to enable native module discovery via zephyr/module.yml, removing duplicate rsource in app/Kconfig.
Hardware Verification:
- Verified clean builds of build_lm20 and build_l15.
- Flashed physical nRF54LM20-DK (Master Tx) and nRF54L15-DK (Slave Rx) over J-Link, confirming stable full-duplex 48 kHz streaming on serial consoles.

lgirdwood force-pushed the feature/nordic-sof-port branch 3 times, most recently from 58c5263 to 1dd21ce Compare October 15, 2026 16:38

lgirdwood force-pushed the feature/nordic-sof-port branch from 1dd21ce to fc42158 Compare November 10, 2026 16:06

lgirdwood requested a balanced review from Copilot November 10, 2026 16:12

Copilot AI reviewed Nov 10, 2026

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lgirdwood commented Nov 10, 2026

View reviewed changes

Copilot stopped reviewing on behalf of lgirdwood due to an error November 10, 2026 16:35
The job was not acquired by a runner even after multiple attempts.

lrgirdwo added 6 commits November 10, 2026 22:54

lgirdwood force-pushed the feature/nordic-sof-port branch from fc42158 to f583f24 Compare November 10, 2026 22:55


		dev->ipc_config = *config;

		iad = rzalloc(SOF_MEM_FLAG_USER, sizeof(*iad));

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lgirdwood commented Sep 22, 2026

Summary

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lgirdwood commented Nov 10, 2026

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