Hello RK1828

The previous section got a pure-print Hello World running. This section detects the RK1828's PCIe device nodes and prints out the NPU device information.

Overall block diagram:

Host SoC (RK3588)                           RK1828 (PCIe co-processor)
─────────────────────                       ──────────────────────────
Application CPU + syscalls                  No application CPU
     │                                       │
     ▼                                       │
Run hello_rk1828 (detect PCIe)               │
     │                                       │
     ▼                                       │
PCIe Gen3 x4 → /dev/dri/renderD128 ────────►  NPU inference entry

1. Prerequisites

Requirement	Description
Host SoC (RK3588) flashed with firmware and booted	Provides the OS and CPU
Cross-compile toolchain installed	`aarch64-linux-gnu-gcc`
PCIe device `0004:41:00.0` present on the Host	Identifies the RK1828

2. Write the code

Create a file hello_rk1828.c:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/sysinfo.h>

int main(int argc, char **argv) {
    printf("================================\n");
    printf("  Hello RK1828!\n");
    printf("================================\n\n");

    struct sysinfo info;
    sysinfo(&info);

    printf("系统运行时间: %ld 秒\n", info.uptime);
    printf("总内存:      %ld MB\n", info.totalram / 1024 / 1024);
    printf("空闲内存:    %ld MB\n", info.freeram / 1024 / 1024);

    printf("\n--- /proc/cpuinfo (摘要) ---\n");
    system("grep -m1 'model name' /proc/cpuinfo 2>/dev/null || "
           "grep -m1 'CPU implementer' /proc/cpuinfo");
    system("grep -m1 'BogoMIPS' /proc/cpuinfo");

    printf("\n--- RK1828 NPU 设备 (PCIe) ---\n");
    system("ls -l /dev/dri/renderD128 2>/dev/null && "
           "echo 'RK1828 PCIe 设备就绪' || "
           "echo '未发现 RK1828 设备，请检查 PCIe链接'");

    printf("\n--- PCIe 拓扑 ---\n");
    system("lspci -s 0004:41:00.0 2>/dev/null || echo 'lspci 未找到该地址'");

    printf("\n程序执行完毕。\n");
    return 0;
}

3. Compile

aarch64-linux-gnu-gcc hello_rk1828.c -o hello_rk1828 -static

# Verify
file hello_rk1828

Output:

hello_rk1828: ELF 64-bit LSB executable, ARM aarch64, version 1 (GNU/Linux), statically linked, BuildID[sha1]=669625d82ce36b9b5617b050831b8bb203190fbe, for GNU/Linux 3.7.0, not stripped

Using -static avoids libc version mismatch issues on the dev board.

4. Deploy

scp

scp hello_rk1828 root@<Host SoC IP>:/tmp/

NFS / Samba mount

Suited to fast-iteration development workflows.

USB drive / SD card

cp hello_rk1828 /media/$USER/USBDRIVE/

5. Run it

Expected output:

Hello RK1828 program output — memory/CPU/RK1828 PCIe device/topology

The uptime / free memory / /dev/dri/renderD128 timestamps are dynamic values and differ on every run.

6. Verify the key nodes individually

PCIe device details:

lspci -s 0004:41:00.0

Output:

0004:41:00.0 Processing accelerators: Rockchip Electronics Co., Ltd Device 182a (rev 01)

The /dev/dri/renderD128 device node:

ls -l /dev/dri/renderD128

Output (measured):

crw-rw----+ 1 root render 226, 128  8月20日 16:56 /dev/dri/renderD128

Contents of /dev/dri/:

ls /dev/dri/

Output:

by-path
card0
card1
renderD128
renderD129

RK1828 PCIe device verified: the device node /dev/dri/renderD128 exists and corresponds to PCIe device 0004:41:00.0 (Rockchip Device 182a).

7. Call the RK1828 NPU

Hello World is only the beginning — to actually use the RK1828's NPU you still call rkllm3-server over PCIe:

# Start the NPU inference service (run on the Host)
rkllm3-server -m <model.rknn> -c 0xff -n 4096
# -m model file path
# -c NPU core mask (use 0xff for 8 cores)
# -n max number of tokens to generate

See section 6 of Hello World for details.

8. FAQ

Symptom	Cause	Fix
`cannot execute binary file`	Architecture mismatch	Make sure it was built with `aarch64-linux-gnu-gcc`
`not found` / missing library	Dynamic linking missing	Add `-static` or check with `ldd` on the Host
`Permission denied`	No execute permission	`chmod +x`
Program runs but the NPU does nothing	Wrong device path probed	The RK1828 device node is `/dev/dri/renderD128`
`rkllm3-server` crashes after a while	Residual KV cache	Restart the service

Hello World — basic getting started
Hardware Architecture Overview — hardware specs
NPU Subsystem — NPU inference