🛠 Remoteproc : inventorier et démarrer les co-processeurs R5F et C66x

Objectives

The TDA4VM on the AI-64 is heterogeneous: 2 Cortex-A72, 6 Cortex-R5F (3 pairs), 2 C66x DSPs, one C7x+MMA (~8 TOPS INT8), and 12 PRUs. Linux exposes these via remoteproc with memory carveouts reserved in the device tree. You will inventory these remote cores and start a signed RTOS firmware on a DSP.

Hardware

• 1 BeagleBone AI-64 running a Debian BeagleBoard or Ubuntu TI Edge AI image
• RTOS firmware from the TI Processor SDK RTOS for J721E (signed x509 images)
• Backup of your configuration before manipulating /sys

Complete Code

# 1. Inventaire des cores distants (C66x, R5F, C7x selon l'image)
for r in /sys/class/remoteproc/remoteproc*; do
  echo "$r name=$(cat $r/name) state=$(cat $r/state)"
done

# 2. Démarrer un firmware RTOS sur un DSP C66x (nom d'exemple, voir SDK)
sudo cp j7-boneai-remoteproc.x509 /lib/firmware/
echo j7-boneai-remoteproc.x509 | sudo tee /sys/class/remoteproc/remoteproc1/firmware
echo start | sudo tee /sys/class/remoteproc/remoteproc1/state
cat /sys/class/remoteproc/remoteproc1/state      # attendu : running

# 3. Le printf du DSP remonte dans le log noyau (RPMsg/virtio)
sudo dmesg | tail -20

# 4. Arrêt propre
echo stop | sudo tee /sys/class/remoteproc/remoteproc1/state

Expected Verification

The list displays several remoteproc entries with names like 4d00000.dsp (C66x) or 5d00000.r5f (R5F); after start, the state changes to running and the firmware's serial traces appear in dmesg. Stopping returns the state to offline without kernel errors.

Common Errors

• Unsigned firmware: The K3 boot chain requires signed images (x509 envelope); a raw binary is rejected by the remote processor loader.
• Changing remoteproc indices: remoteproc0/1 numbering depends on the kernel and probe order — always script by core name, never by index.
• Older mainline kernel: The C6x carveout was long inverted in the DTS (fixed by commit 1a314099b755); update before concluding it is a hardware defect.
• Rare TISCI crash during GPU power-up (approx. 1 boot in 1000, issue #44): Mbox timedout at boot = image needs updating, no panic.
• Exact firmware file names vary depending on the SDK: refer to the TI Processor SDK J721E documentation for YOUR version.