Feature request: Add `--dtb-discovery` flag for direct DTB device discovery

[FrancescoScappatura-Ax]

Feature Request: Add --dtb-discovery flag for direct DTB device discovery

Description

I'd like to propose adding a --dtb-discovery flag that enables direct device discovery from the device tree blob (DTB), allowing Spike to automatically instantiate devices defined in the DTB without requiring individual --device flags for each instance.

Motivation

Currently, when working with multiple instances of the same device type or with a relevant number of devices in general, each instance must be specified separately via --device flags:

spike --device=counter,0x30000000,0x1000 \
      --device=counter,0x30001000,0x1000 \
      --device=counter,0x30002000,0x1000 \
      ...

This becomes cumbersome with many devices. A DTB-based approach would be IMHO cleaner:

counter@30000000 { 
  compatible = "counter";
  reg = <0x0 0x30000000 0x0 0x1000>;
  spike,plugin-params = "0x30000000,0x1000";
};
counter@30001000 { 
  compatible = "counter";
  reg = <0x0 0x30001000 0x0 0x1000>;
  spike,plugin-params = "0x30001000,0x1000";
};

spike --dtb=system.dtb --dtb-direct fw_payload.elf

Proposed Behavior

• --dtb-direct: Enable direct device discovery from DTB
• Requires --dtb to be specified
• Incompatible with --device (conflicting specification methods)
• Spike would scan the DTB and instantiate devices based on their compatible properties
• Custom plugin parameters can be passed via spike_plugin_params property in the device tree node, which would be parsed and passed to the plugin's initialization function

Questions

• Does this feature make sense for Spike's architecture?
• Are there any concerns or edge cases I'm missing?
• If this seems reasonable, I'd be happy to work on implementing it and submit a PR

Thank you for considering this request!

[FrancescoScappatura-Ax]

I created a PR here #2165 to show a PoC of the feature.