feat(fdt): change memory method to return iterator for multiple nodes

The memory() method now returns an iterator that can yield multiple memory
nodes instead of returning just the first one found. This allows handling
device trees with multiple memory regions.

BREAKING CHANGE: The memory() method return type changed from
Option<Memory<'a>> to impl Iterator<Item = Memory<'a>> + 'a. Callers must
now use .next() or other iterator methods to access memory nodes.

Author: ZR233

fdt-edit/Cargo.toml

@@ -11,7 +11,7 @@ license = "MIT OR Apache-2.0"
 name = "fdt-edit"
 readme = "README.md"
 repository = "https://github.com/drivercraft/fdt-parser"
-version = "0.1.5"
+version = "0.1.6"
 
 [dependencies]
 enum_dispatch = "0.3.13"

fdt-raw/src/fdt.rs

@@ -252,6 +252,45 @@ impl<'a> Fdt<'a> {
             }
         })
     }
+
+    pub fn reserved_memory(&self) -> impl Iterator<Item = Node<'a>> + 'a {
+        ReservedMemoryIter {
+            node_iter: self.all_nodes(),
+            in_reserved_memory: false,
+            reserved_level: 0,
+        }
+    }
+}
+
+struct ReservedMemoryIter<'a> {
+    node_iter: FdtIter<'a>,
+    in_reserved_memory: bool,
+    reserved_level: usize,
+}
+
+impl<'a> Iterator for ReservedMemoryIter<'a> {
+    type Item = Node<'a>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(node) = self.node_iter.next() {
+            if node.name() == "reserved-memory" {
+                self.in_reserved_memory = true;
+                self.reserved_level = node.level();
+                continue;
+            }
+
+            if self.in_reserved_memory {
+                if node.level() <= self.reserved_level {
+                    // 已经离开 reserved-memory 节点
+                    self.in_reserved_memory = false;
+                    return None;
+                } else {
+                    return Some(node);
+                }
+            }
+        }
+        None
+    }
 }
 
 impl fmt::Display for Fdt<'_> {

fdt-raw/tests/rsv.rs

@@ -0,0 +1,48 @@
+use std::sync::Once;
+
+use dtb_file::{fdt_qemu, fdt_rpi_4b};
+use fdt_raw::Fdt;
+
+fn init_logging() {
+    static INIT: Once = Once::new();
+    INIT.call_once(|| {
+        let _ = env_logger::builder()
+            .is_test(true)
+            .filter_level(log::LevelFilter::Trace)
+            .try_init();
+    });
+}
+
+#[test]
+fn test_rsv1() {
+    init_logging();
+
+    let raw = fdt_qemu();
+    let fdt = Fdt::from_bytes(&raw).unwrap();
+
+    for node in fdt.reserved_memory() {
+        println!("reserved memory node: {}", node.name());
+        let ranges = node.ranges().unwrap();
+        for range in ranges.iter() {
+            println!("  range: {range:#x?}");
+        }
+    }
+}
+
+#[test]
+fn test_rsv2() {
+    init_logging();
+
+    let raw = fdt_rpi_4b();
+    let fdt = Fdt::from_bytes(&raw).unwrap();
+
+    for node in fdt.reserved_memory() {
+        println!("reserved memory node: {}", node.name());
+    }
+
+    let want_names = ["linux,cma", "nvram@0", "nvram@1"];
+
+    for (i, node) in fdt.reserved_memory().enumerate() {
+        assert_eq!(node.name(), want_names[i]);
+    }
+}