Audio DSP

Build SOF Firmware

The SOF project aims to provide an open-source audio DSP firmware and software stack for audio devices. This guide will explain how to use SOF docker image to build SOF firmware for the Genio 510/700/1200-EVK.

Set up the SOF workspace

1. Establish a directory to store all the SOF work.

SOF_WORKSPACE=~/sof_work
mkdir -p "$SOF_WORKSPACE"

2. Clone the SOF repository.

cd "$SOF_WORKSPACE"
git clone --recurse-submodules https://github.com/thesofproject/sof.git

Get the SOF Docker Image

To build SOF binaries, a Docker image with the necessary platform-related cross-compiler and build environment dependencies are required. Building SOF binaries using Docker can save time compared to building them from source code, as building the toolchains from the source code might take several hours.

For information on how to install Docker, please visit Set up Docker.

1. Pull the Docker image from Docker Hub. Please make sure your platform has an internet connection.

docker pull thesofproject/sof

Build Firmware Binaries

If you execute the xtensa-build-all.sh script without specifying the platforms, this script will build firmware binaries for all the platforms listed in the script. This script allows specifying the platform binaries to be built by adding the platform alias suffixes at the end of the command.

To build the SOF binaries for Genio platforms:

cd "$SOF_WORKSPACE"/sof/

Genio 510/700-EVK
./scripts/docker-run.sh ./scripts/xtensa-build-all.sh mt8188

Genio 1200-EVK
./scripts/docker-run.sh ./scripts/xtensa-build-all.sh mt8195

Genio 510/700-EVK, Genio 1200-EVK
./scripts/docker-run.sh ./scripts/xtensa-build-all.sh mt8188 mt8195

The firmware binaries are located in the build_<platform>/src/arch/xtensa/ directory. Copy them to the /lib/firmware/mediatek/sof directory on the target machine.

Build SOF Topology

cd "$SOF_WORKSPACE"/sof/
./scripts/docker-run.sh ./scripts/build-tools.sh

The topology files are located in the "$SOF_WORKSPACE"/sof/tools/build_tools/topology folder. Copy the files to the /lib/firmware/mediatek/sof-tplg directory on the target machine.

Build SOF Tools

SOF tools are a collection of utilities and scripts designed to facilitate the development, debugging, and deployment of audio firmware on various platforms.

The SOF topology and SOF tools are both compiled together using the same scripts - ./scripts/build-tools.sh. However, if you intend to use SOF tools on Genio platforms, please ensure that they are compiled using the ARM architecture.

The application SDK can be used for building 3rd party software if IoT Yocto does not provide them. You can use the application SDK to build the SOF tools. For more details, please refer to the Application SDK.

• sof-logger

  sof-logger is a specialized tool used within the SOF project to capture and display logs generated by the SOF firmware. These logs are crucial for debugging, performance analysis, and monitoring the behavior of the audio DSP firmware. sof-logger captures logs from the SOF firmware on the DSP, providing real-time insights into the firmware’s operations.

  To use sof-logger, please enable these configs at recipes-kernel/linux/linux-mtk/sof.cfg while building the platform image.

  - EXPERT
  - SND_SOC_SOF_DEVELOPER_SUPPORT
  - SND_SOC_SOF_DEBUG
  - SND_SOC_SOF_DEBUG_VERBOSE_IPC (optional)
  - SND_SOC_SOF_DEBUG_ENABLE_FIRMWARE_TRACE (optional)
  

  Ensure you have the logger configuration file (sof-<platform>.ldc) which contains the necessary metadata for decoding the logs. sof-<platform>.ldc is built with the SOF firmware binary. Copy the file to the directory /lib/firmware/mediatek/sof on the target machine.

  Here is a basic example to run sof-logger:

  ./sof-logger -l sof-mt8188.ldc -t
  

  For more sof-logger usage, please refer to here.

Example

This section provides a detailed example and instructions on how to modify the topology in Sound Open Firmware (SOF), specifically by adding a new audio processing component such as a volume control (PGA) to an existing pipeline.

1. Locate the Topology File:

   Find the .m4 file corresponding to the topology you want to modify, typically located in the /tools/topology/topology1/ directory of the SOF source.

   The snippet shows the MT8188 topology (sof-mt8188-mt6359.m4) for capture devices:

   # Low Latency capture pipeline 3 on PCM 18 using max 2 channels of s16le
   # Set 2000us deadline with priority 0 on core 0
   PIPELINE_PCM_ADD(sof/pipe-passthrough-capture.m4,
       3, 18, 2, s16le,
       2000, 0, 0,
       48000, 48000, 48000)
   
   # Low Latency capture pipeline 4 on PCM 19 using max 2 channels of s16le
   # Set 2000us deadline with priority 0 on core 0
   PIPELINE_PCM_ADD(sof/pipe-passthrough-capture.m4,
       4, 19, 2, s16le,
       2000, 0, 0,
       48000, 48000, 48000)
   

2. Modify the Topology:

   Add a new volume capture component (PGA) to the pipeline, replacing the passthrough filter, as shown in the snippet:

   # Low Latency capture pipeline 3 on PCM 18 using max 2 channels of s16le
   # Set 2000us deadline with priority 0 on core 0
   PIPELINE_PCM_ADD(sof/pipe-volume-capture.m4,
       3, 18, 2, s16le,
       2000, 0, 0,
       48000, 48000, 48000)
   
   # Low Latency capture pipeline 4 on PCM 19 using max 2 channels of s16le
   # Set 2000us deadline with priority 0 on core 0
   PIPELINE_PCM_ADD(sof/pipe-passthrough-capture.m4,
       4, 19, 2, s16le,
       2000, 0, 0,
       48000, 48000, 48000)
   

3. Rebuild the Topology:

   After modifying the .m4 file, rebuild the topology to generate the .tplg file.

   cd "$SOF_WORKSPACE"/sof/
   ./scripts/docker-run.sh ./scripts/build-tools.sh
   

4. Deploy the Topology:

   The topology file is located in the "$SOF_WORKSPACE"/sof/tools/build_tools/topology folder.

   Copy the file to the /lib/firmware/mediatek/sof-tplg directory on the target machine (replacing the existing topology file) and restart the device for the changes to take effect.

5. Verify the New Topology:

   Check logs to ensure there are no errors related to SOF or the audio pipeline:

   dmesg | grep sof
   

   Check the amixer settings to find the newly added component:

   root@genio-510-evk:~# amixer -c0 | grep -A5 PGA3.0
   Simple mixer control 'PGA3.0 3 Master',0
       Capabilities: cvolume
       Capture channels: Front Left - Front Right
       Limits: Capture 0 - 80
       Front Left: Capture 50 [62%] [0.00dB]
       Front Right: Capture 50 [62%] [0.00dB]
   

   Tweak the component parameters:

   root@genio-510-evk:~# amixer -c0 cset numid=366 80,80
   numid=366,iface=MIXER,name='PGA3.0 3 Master Capture Volume'
     ; type=INTEGER,access=rw---R--,values=2,min=0,max=80,step=0
     : values=80,80
     | dBscale-min=-50.00dB,step=1.00dB,mute=1
   

   Validate the changes:

   root@genio-510-evk:~# amixer -c0 sget 'PGA3.0 3 Master'
   Simple mixer control 'PGA3.0 3 Master',0
      Capabilities: cvolume
      Capture channels: Front Left - Front Right
      Limits: Capture 0 - 80
      Front Left: Capture 80 [100%] [30.00dB]
      Front Right: Capture 80 [100%] [30.00dB]
   

   Test the audio capture to verify component functionality:

   arecord -Dhw:0,18 -c2 -fS16_LE -d30 -r48000 test.wav
   

For more information on SOF topology, please refer to this: https://thesofproject.github.io/latest/developer_guides/topology/topology