rust: of: Add reserved_mem_region_to_resource_byname()

Creates Resource from a reserved memory region. Depends on commit
f4fcfdd ("of: reserved_mem: Add functions to parse
"memory-region"") from v6.16-rc1.

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

rust/bindings/bindings_helper.h

@@ -60,6 +60,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/pci.h>
 #include <linux/phy.h>
 #include <linux/pid_namespace.h>

rust/kernel/of.rs

@@ -11,6 +11,9 @@ use crate::{bindings, device_id::RawDeviceId, prelude::*};
 use core::marker::PhantomData;
 use core::num::NonZeroU32;
 
+use crate::error::to_result;
+use crate::io::resource::Resource;
+
 /// IdTable type for OF drivers.
 pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
 
@@ -211,6 +214,30 @@ impl Node {
         }
     }
 
+    #[allow(unused_variables)]
+    /// Get a reserved memory region as a resource
+    pub fn reserved_mem_region_to_resource_byname(&self, name: &CStr) -> Result<Resource> {
+        #[cfg(not(CONFIG_OF))]
+        {
+            Err(ENOENT)
+        }
+        #[cfg(CONFIG_OF)]
+        {
+            let res = Resource::zeroed();
+            // SAFETY: This function is safe to call as long as the arguments are valid pointers.
+            let ret = unsafe {
+                bindings::of_reserved_mem_region_to_resource_byname(
+                    self.raw_node,
+                    name.as_char_ptr(),
+                    res.as_raw(),
+                )
+            };
+            to_result(ret)?;
+
+            Ok(res)
+        }
+    }
+
     #[allow(unused_variables)]
     /// Look up a node property by name, returning a `Property` object if found.
     pub fn find_property(&self, propname: &CStr) -> Option<Property<'_>> {