Getting timestamp does not have to be mutable

Author: datdenkikniet

src/dma/mod.rs

@@ -248,10 +248,7 @@ impl<'rx, 'tx> EthernetDMA<'rx, 'tx> {
     /// 2. Before calling [`interrupt_handler`](EthernetDMA::interrupt_handler) again, retrieve timestamps of sent and received frames using this function.
     ///
     /// Retrieving RX timestamps can also be done using [`RxPacket::timestamp`].
-    pub fn get_timestamp_for_id<'a, PKT>(
-        &mut self,
-        packet_id: PKT,
-    ) -> Result<Timestamp, TimestampError>
+    pub fn get_timestamp_for_id<'a, PKT>(&self, packet_id: PKT) -> Result<Timestamp, TimestampError>
     where
         PKT: Into<PacketId>,
     {

src/dma/raw_descriptor.rs

@@ -78,7 +78,11 @@ impl<'data, T> DescriptorRing<'data, T> {
         (&mut self.descriptors[index], &mut self.buffers[index])
     }
 
-    pub fn descriptors(&mut self) -> impl Iterator<Item = &mut T> {
+    pub fn descriptors(&self) -> impl Iterator<Item = &T> {
+        self.descriptors.iter()
+    }
+
+    pub fn descriptors_mut(&mut self) -> impl Iterator<Item = &mut T> {
         self.descriptors.iter_mut()
     }
 

src/dma/rx/mod.rs

@@ -148,7 +148,7 @@ impl<'data> RxRing<'data, Running> {
 
 #[cfg(feature = "ptp")]
 impl<'data, STATE> RxRing<'data, STATE> {
-    pub fn get_timestamp_for_id(&mut self, id: PacketId) -> Result<Timestamp, TimestampError> {
+    pub fn get_timestamp_for_id(&self, id: PacketId) -> Result<Timestamp, TimestampError> {
         for descriptor in self.ring.descriptors() {
             if let (Some(packet_id), Some(timestamp)) =
                 (descriptor.packet_id(), descriptor.timestamp())

src/dma/tx/mod.rs

@@ -157,15 +157,12 @@ impl<'data> TxRing<'data, Running> {
 #[cfg(feature = "ptp")]
 impl<'data> TxRing<'data, Running> {
     pub(crate) fn collect_timestamps(&mut self) {
-        for descriptor in self.ring.descriptors() {
+        for descriptor in self.ring.descriptors_mut() {
             descriptor.attach_timestamp();
         }
     }
 
-    pub(crate) fn get_timestamp_for_id(
-        &mut self,
-        id: PacketId,
-    ) -> Result<Timestamp, TimestampError> {
+    pub(crate) fn get_timestamp_for_id(&self, id: PacketId) -> Result<Timestamp, TimestampError> {
         let descriptor = if let Some(descriptor) =
             self.ring.descriptors().find(|d| d.packet_id() == Some(&id))
         {