From 251ea035fa2338db7b001af338d65875a9bc65ad Mon Sep 17 00:00:00 2001
From: Nathan Ringo <nathan@remexre.com>
Date: Tue, 27 Aug 2024 00:20:19 -0500
Subject: Adds a free-list for physical memory.

---
 kernel/src/device_tree.rs | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

(limited to 'kernel/src/device_tree.rs')

diff --git a/kernel/src/device_tree.rs b/kernel/src/device_tree.rs
index 5fdc3e9..c045cfd 100644
--- a/kernel/src/device_tree.rs
+++ b/kernel/src/device_tree.rs
@@ -6,13 +6,13 @@ use contracts::requires;
 use core::{
     fmt, iter,
     num::ParseIntError,
+    ops::Range,
     slice,
     str::{self, Utf8Error},
 };
 use either::Either;
 
 /// A reference to a flattened DeviceTree (DTB) in memory.
-#[derive(Debug)]
 pub struct FlattenedDeviceTree<'dt> {
     header: &'dt FdtHeader,
     struct_block: &'dt [u32],
@@ -127,6 +127,24 @@ impl<'dt> FlattenedDeviceTree<'dt> {
         Ok(())
     }
 
+    /// Returns an iterator over the reserved ranges of addresses.
+    ///
+    /// Addresses may be reserved by:
+    ///
+    /// - Overlapping with the DeviceTree itself.
+    /// - Overlapping with any memory reservations in the DeviceTree.
+    pub fn iter_reserved(&self) -> impl '_ + Iterator<Item = Range<usize>> {
+        // Make the address range of the DeviceTree.
+        let dt_start = self.header as *const FdtHeader as usize;
+        let dt_end = dt_start + u32::from_be(self.header.totalsize) as usize;
+
+        iter::once(dt_start..dt_end).chain(self.memrsv_block.iter().map(|memrsv| {
+            let addr = u64::from_be(memrsv.addr) as usize;
+            let size = u64::from_be(memrsv.size) as usize;
+            addr..addr + size
+        }))
+    }
+
     /// Returns an iterator over the events in the structure block of the DeviceTree, starting at
     /// the current offset from the start of the structure block.
     ///
@@ -244,6 +262,14 @@ impl<'dt> FlattenedDeviceTree<'dt> {
     }
 }
 
+impl<'dt> fmt::Debug for FlattenedDeviceTree<'dt> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let addr = self.header as *const FdtHeader;
+        // Intentionally not using `fmt.debug_tuple`, it's wasted space here.
+        write!(fmt, "FlattenedDeviceTree::from_ptr({addr:p})")
+    }
+}
+
 /// An error encountered when reading a DeviceTree.
 #[derive(Debug)]
 pub enum DeviceTreeError {
-- 
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