corsair-status-writer.py

#!/usr/bin/env python3
"""
Reads Corsair AI Workstation 300 ERAX MMIO region and writes status JSON
to /run/corsair-status every second. Run as root via systemd service.
"""

import mmap, os, time, json, signal, sys

ERAX_BASE = 0xFEC40400
STATUS_FILE = "/run/corsair-status"

MODES = {0: "Balanced", 1: "Max", 2: "Quiet", 3: "Super"}

page_size = 4096
page_addr = ERAX_BASE & ~(page_size - 1)
base      = ERAX_BASE - page_addr

fd = os.open("/dev/mem", os.O_RDONLY | os.O_SYNC)
m  = mmap.mmap(fd, page_size, mmap.MAP_SHARED, mmap.PROT_READ, offset=page_addr)

def d(off):
    return m[base + off]

def read_status():
    mode_raw = d(0x31)
    fan1     = (d(0x35) << 8) | d(0x36)
    fan2     = (d(0x37) << 8) | d(0x38)
    return {
        "mode":     MODES.get(mode_raw, f"Unknown"),
        "mode_raw": mode_raw,
        "fan1":     fan1,
        "fan2":     fan2,
        "cput":     d(0x70),
        "gput":     d(0x71),
    }

def cleanup(sig, frame):
    m.close()
    os.close(fd)
    try:
        os.unlink(STATUS_FILE)
    except FileNotFoundError:
        pass
    sys.exit(0)

signal.signal(signal.SIGTERM, cleanup)
signal.signal(signal.SIGINT, cleanup)

tmp = STATUS_FILE + ".tmp"
while True:
    status = read_status()
    data   = json.dumps(status) + "\n"
    with open(tmp, "w") as f:
        f.write(data)
    os.replace(tmp, STATUS_FILE)
    os.chmod(STATUS_FILE, 0o644)
    time.sleep(1)