RK2118 NPU quickstart, part 3: RT-Thread and DSP firmware

Platform reference for RK_EVB1_RK2118G_V20 (RK2118) and its matching RT-Thread SDK. No corresponding ArmSoM board has been confirmed; do not transfer these instructions directly to another SoC. No validated BSP or Linux kernel is specified and no ArmSoM hardware testing was performed.

Source: local Chinese and English RKNN2 RK2118 QuickStart V2.5.0; original section numbers are retained. Chinese follows its source; English, Russian and German follow the English source. PDF-wrapped filenames, URLs, comments and commands are rejoined. Section 5.3 points to 3.1 for the RT-Thread download, but the download steps are in 3.3.1. The Docker command mounts /rt-thread, while the subsequent command uses the relative path rt-thread/…; check the container working directory. This discrepancy was not silently rewritten. Sample logs, 45ms and reference outputs belong to the source, not ArmSoM tests. Unpinned/latest installation commands do not guarantee V2.5.0; check the actual SDK.

Rockchip source

RK2118 quickstart series · 3/5

RK2118 NPU quickstart, part 1: hardware, connections and serial console

RK2118 NPU quickstart, part 2: host environment and Toolkit2 installation

RK2118 NPU quickstart, part 3: RT-Thread and DSP firmware

RK2118 NPU quickstart, part 4: model conversion, USB inputs and inference results

RK2118 NPU quickstart, part 5: Docker, FAQ and references

3.3 Prepare RK2118 SDK

The example of NPU is included in the RK2118 SDK, so you need to prepare the RK2118 SDK source code first.

3.3.1 Repository Download

• Download repo tool. If repo is already installed, please skip this step.

git clone ssh://git@www.rockchip.com.cn/repo/rk/tools/repo -b stable
export PATH=/path/to/repo:$PATH

• repository download

mkdir rt-thread
cd rt-thread
repo init --repo-url ssh://git@www.rockchip.com.cn/repo/rk/tools/repo -u ssh://git@www.rockchip.com.cn/rtos/rt-thread/rk/platform/release/manifests -b master -m rk2118.xml
.repo/repo/repo sync

Note: This project requires authorization to access, please contact Rockchip to apply.

3.3.2 Compilation environment preparation

Please refer to Rockchip_Developer_Guide_RK2118_CN.pdf in the rt-thread/Rockchips-docs/manuals/rk2118 directory to build the development environment.

3.3.3 RK2118 firmware compilation

3.3.3.1 Enable RKNPU support

Refer to Chapter 4, “CPU Firmware Compilation,” of Rockchip_Developer_Guide_RK2118_CN.pdf to compile the firmware and enable RKNPU support. Return to the main directory of the rt-thread project and execute the following command:

cd bsp/rockchip/rk2118
cp board/evb1_v20/defconfig_npu_demo .config
scons --menuconfig

Please make sure the following options are turned on:

RT-Thread Components --->
  [*] DFS: device virtual file system --->
       [*] Using posix-like functions, open/read/write/close
       [*] Using working directory
       (4) The maximal number of mounted file system
       (4) The maximal number of file system type
       (16) The maximal number of opened files
       [*] Using mount table for file system
       [*] Enable elm-chan fatfs
RT-Thread board config --->
  [*] using DRAM, only available for RK2118B or RK2118G
  [*] Enable hifi4 driver
  HIFI4 Project --->
    [*] HIFI4 Projects
    (X) npu Demo
  rknn dsp communication config --->
    [*] Enable rknn dsp demo communication for rk2118
RT-Thread rockchip RK2118 drivers --->
  Enable RKNPU Driver --->
    [*] Enable RKNPU Driver
    (X) RKNPU Driver in DSP

Notes:

• board/evb1_v20/defconfig_npu_demo already includes all of the options listed above, so manual configuration is generally unnecessary. scons –menuconfig should only be used for temporary inspection or experimentation.

• For the NPU driver location, select “RKNPU Driver in DSP” ( RT_USING_RKNPU_DSP_DRIVER ). In this SDK, the NPU demo runs the RKNN firmware on HIFI4 DSP0 ( components/hifi4/samples/rk2118/npu_demo ), while CPU0 communicates with the DSP through rknn_demo_server . The CPU-direct “RKNPU Driver in RTT” path is not compatible with this demo.

• After “npu Demo” is selected, the RKNN DSP communication components are selected automatically, and the DSP memory layout file components/hifi4/samples/rk2118/npu_demo/mem_layout.h is fixed automatically. No manual configuration is required.

• Each time build.sh is executed, .config is overwritten with the corresponding defconfig. For persistent configuration changes, modify board/evb1_v20/defconfig_npu_demo directly.

• The firmware build and packaging command for this board is: ./build.sh board/evb1_v20/package-file npu_demo

This generates Image/update.img , which includes the dsp0 , dsp1 , and dsp2 firmware partitions for npu_demo .

3.3.3.2 Compile firmware and package

cd bsp/rockchip/rk2118
./build.sh board/evb1_v20/package-file npu_demo

This command performs both the build and packaging steps in a single operation:

1. Overwrite .config with board/evb1_v20/defconfig_npu_demo , then build the CPU0/CPU1 firmware.

2. Invoke mkimage.sh to package dsp0.bin , dsp1.bin , and dsp2.bin from components/hifi4/rtt/dsp_fw/npu_demo/ into the image as DSP firmware partitions ( Type=0x400 ).

3. Generate the final image at Image/update.img .

Notes:

• If only CPU-side code is modified, you can run scons -j32 to rebuild the firmware, and then run ./mkimage.sh board/evb1_v20/package-file npu_demo to package the image.

• If the DSP project is modified (for example, components/hifi4/samples/rk2118/npu_demo/npu_demo_dsp0 ), you must first rebuild the Xtensa project to regenerate dsp0.bin under rtt/dsp_fw/npu_demo/ , and then run the packaging command. Otherwise, the image will still contain the old DSP firmware.

• The DSP firmware partition path is automatically updated by the second argument to mkimage.sh ( npu_demo ). Do not modify package-file manually.

3.3.3.3 Flashing firmware

Refer to Section 4.1.3.4, “Firmware Burning,” of Rockchip_Developer_Guide_RK2118_CN.pdf to flash the firmware to the development board. You can also use the upgrade tool included with the SDK to flash update.img :

upgrade_tool uf Image/update.img