Welcome to the project documentation for RPMsg DMA Offload. This project demonstrates RPMsg-based general purpose DSP offloading from Linux to remore core on AM62Dx evm platforms using TI's ti-rpmsg-char and Linux DMA Heaps.
This repository contains:
- A shared library
libti_rpmsg_dma.sofor interfacing with RPMsg and DMA Heaps - Demo applications
rpmsg_audio_offload_example:
- FFT-based audio processing (Band pass filtering)
- ARM/DSP execution switching
- IP-based(ethernet) and uart based monitoring, runtime control and logging
rpmsg_2dfft_offload_example:
- Test data 2DFFT processing on C7x DSP
rpmsg_sigchain_biquad_linux_example:
- Real-time 3-stage parametric equalizer (biquad cascade) on C7x DSP
- Network-based GUI control and monitoring
- MCASP audio I/O with I2C codec control
- Live DSP performance monitoring (load, cycles, throughput)
+-----------------------------+
| User Space |
| |
| +---------------------+ |
| | rpmsg_audio_offload_example | <- Example App
| +---------------------+ |
| | |
| v |
| +---------------------+ |
| | libti_rpmsg_dma.so | <- Shared Library
| +---------------------+ |
| | |
+----------|-----------------+
v
[ /dev/rpmsg_charX ] (TI rpmsg-char)
[ /dev/dma_heap/... ] (Linux DMA Heaps)
+-----------------------------+
| DSP |
| - Processes offloaded audio
+-----------------------------+
library/include/ - Public headers
library/src/ - Library source files
library/lib/, library/obj - Build outputs (ignored by git)
example/audio_offload/
├── src/ - Example source
├── inc/ - Example headers
├── audio_sample/ - Audio sample file (8ch 48Khz)
├── host utility/EQ_CTL.py - Host side python utility to monitor and control EQ params
├── firmware - C7 DSP firmware for examples
├── config/dsp_offload.cfg - Runtime config file
example/2dfft/
├── src/ - Example source
├── inc/ - Example headers
├── test_data/ - Input sample and expected output sample data
├── firmware - C7 DSP firmware for examples
example/sigchain_biquad/
├── src/ - Example source
├── inc/ - Example headers
├── host_utility/ - Host side python utility for monitor and control
├── firmware - C7x DSP firmware for example
CMakeLists.txt
LICENSE
README.md
RPMSG API Endpoints
init_rpmsg
Description: Initializes the RPMSG communication.
Parameters:
rproc_id: The ID of the remoteproc device.
rmt_ep: The remote endpoint number.
Returns: The file descriptor of the RPMSG channel.
Example: int fd = init_rpmsg(1, 2);
send_msg
Description: Sends a message over the RPMSG channel.
Parameters:
fd: The file descriptor of the RPMSG channel.
msg: The message to be sent.
len: The length of the message.
Returns: The number of bytes sent.
Example: int sent = send_msg(fd, "Hello, world!", 13);
recv_msg
Description: Receives a message over the RPMSG channel.
Parameters:
fd: The file descriptor of the RPMSG channel.
len: The length of the message to be received.
reply_msg: A pointer to a buffer to store the received message.
reply_len: A pointer to store the length of the received message.
Returns: 0 on success, -1 on error.
Example: int len = 0; char reply[1024]; int ret = recv_msg(fd, 1024, reply, &len);
cleanup_rpmsg
Description: Cleans up the RPMSG channel and releases its resources.
Parameters:
fd: The file descriptor of the RPMSG channel.
Example: cleanup_rpmsg(fd);
DMABUF API Endpoints
dmabuf_heap_init
Description: Initializes a DMA heap and returns its file descriptor.
Parameters:
heap_name: The name of the DMA heap to initialize.
buffer_size: The size of the buffer to allocate.
rproc_dev: The path to the remoteproc device.
params: A pointer to a struct dma_buf_params object that will hold the DMA buffer parameters.
Returns: The file descriptor of the DMA heap.
Example: int fd = dmabuf_heap_init("heap_name", 1024, "/dev/remoteproc", ¶ms);
dmabuf_sync
Description: Indicates the start or end of a map access session for a DMA buffer.
Parameters:
fd: The file descriptor of the DMA buffer.
start_stop: A flag indicating whether to start (1) or stop (0) the map access session.
Returns: The result of the ioctl system call.
Example: int ret = dmabuf_sync(fd, 1);
dmabuf_heap_destroy
Description: Destroys a DMA buffer and releases its resources.
Parameters: params: A pointer to a struct dma_buf_params object that holds the DMA buffer parameters.
Example: dmabuf_heap_destroy(¶ms);
FW Loader API
switch_firmware
Description: Switches to a new firmware by stopping the current firmware, updating the symlink to the new firmware, and then starting the new firmware.
Parameters:
new_fw: Path to the new firmware file to load.
fw_link: Path to the symlink that points to the current firmware.
remote_proc_state_path: Path to the file that controls the state of the remote processor.
Return Value
0: Success
-1: Failure
To build the shared library and example application, install the following dependencies:
- CMake (version 3.10 or newer)
- C compiler (e.g., gcc)
- pkg-config
- FFTW3 development files (`libfftw3-dev`)
- libsndfile development files (`libsndfile1-dev`)
- ALSA development files (`libasound2-dev`)
- ti-rpmsg-char library (required, must be installed from Texas Instruments AM62x Linux SDK or source)
Run the following commands from the root:
cmake -S . -B build
cmake --build build
- This will build:
- The shared library (`libti_rpmsg_dma.so`)
- The example application (`rpmsg_audio_offload_example`)
To install the built files (requires root privileges):
sudo cmake --install build
This installs:
- The library to `/usr/lib` (by default)
- The example binary to `/usr/bin`
- The configuration file (`dsp_offload.cfg`) to `/etc`
- The sample audio file (`sample_audio.wav`) to `/usr/share/`
- The C7 DSP example firmware files to `/usr/lib/`
- The 2dfft example test data set fils to `usr/share/2dfft_test_data`
- The library header files to `/usr/local/include`
Optional:
To build only the library or only the example, use:
cmake -S . -B build -DBUILD_LIB=OFF # disables library build
cmake -S . -B build -DBUILD_AUDIO_OFFLOAD_EXAMPLE=OFF # disables audio_offload example build
cmake -S . -B build -DBUILD_2DFFT_OFFLOAD_EXAMPLE=OFF # disables 2dfft_offload example build
cmake -S . -B build -DBUILD_SIGCHAIN_BIQUAD_EXAMPLE=OFF # disables sigchain_biquad example build
1. Flash image with `ti-rpmsg-char` support on AM62A/62D.
2. Deploy library:
- `libti_rpmsg_dma.so` to `/usr/lib/`
3. Deploy examples:
1. audio_offload example
- `rpmsg_audio_offload_example` to `/usr/bin/`
- `dsp_offload.cfg` to `/etc/dsp_offload.cfg`
- `sample_audio.wav` to `/usr/share/sample_audio`
- `dsp_audio_filter_offload.c75ss0-0.release.strip.out` to `/usr/lib/firmware`
2. 2dfft_offload example
- `rpmsg_2dfft_example` to `/usr/bin/`
- `2dfft_input_data.bin` to `/usr/share/2dfft_test_data/`
- `2dfft_expected_output_data.bin` to `/usr/share/2dfft_test_data/`
- `dsp_2dfft_offload.c75ss0-0.release.strip.out` to `/usr/lib/firmware`
3. sigchain_biquad example
- `rpmsg_sigchain_biquad_example` to `/usr/bin/` (board-side application)
- `signal_chain_biquad_example_gui.py` to PC (network GUI)
- `sigchain_biquad_cascade_c75ss0-0_freertos_linux.release.strip.out` to `/lib/firmware/`
4. Run:
- Audio offload: `rpmsg_audio_offload_example` (on evm) + `audmon.py <mode: uart|ip> <EVM COM port|IP address>` (on host machine)
- 2D FFT: `rpmsg_2dfft_example`
- Cascade Biquad Parametric EQ Signal Chain Example: `rpmsg_sigchain_biquad_example` (on evm) + `python3 signal_chain_biquad_example_gui.py <EVM IP address>` (on host machine)
4. Monitor UART or system logs for output.
## 📡 Ethernet Commands (only applicable for audio_offload example)
```text
SET FFT FILTER <value>
`
- Value: Bool FFT Filter State (0: OFF, 1: ON)
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