hwd: debug devicetree devices

hwd/src/backend/devicetree.rs

@@ -6,6 +6,27 @@ pub struct DeviceTreeBackend {
     dtb: Vec<u8>,
 }
 
+impl DeviceTreeBackend {
+    fn dump(node: &fdt::node::FdtNode<'_, '_>, level: usize) {
+        let mut line = String::new();
+        for _ in 0..level {
+            line.push_str("  ");
+        }
+        line.push_str(node.name);
+        if let Some(compatible) = node.compatible() {
+            line.push_str(":");
+            for id in compatible.all() {
+                line.push_str(" ");
+                line.push_str(id);
+            }
+        }
+        log::debug!("{}", line);
+        for child in node.children() {
+            Self::dump(&child, level + 1);
+        }
+    }
+}
+
 impl Backend for DeviceTreeBackend {
     fn new() -> Result<Self, Box<dyn Error>> {
         let dtb = fs::read("/scheme/kernel.dtb")?;
@@ -15,7 +36,8 @@ impl Backend for DeviceTreeBackend {
 
     fn probe(&mut self) -> Result<(), Box<dyn Error>> {
         let dt = fdt::Fdt::new(&self.dtb).map_err(|err| format!("failed to parse dtb: {}", err))?;
-        log::info!("TODO: handle driver spawning from devicetree backend");
+        let root = dt.find_node("/").ok_or_else(|| format!("failed to find root node"))?;
+        Self::dump(&root, 0);
         Ok(())
     }
 }