eth: always just allocate desc list + buffers

buffers are allocated vec anyway. this removes the lifetime hack and
further prepares work on cache-line alignment to enable L1 writeback.

experiments/src/main.rs

@@ -4,7 +4,7 @@
 extern crate alloc;
 
 use alloc::{borrow::ToOwned, collections::BTreeMap, format};
-use core::{mem::transmute, task::Poll};
+use core::task::Poll;
 use libasync::{
     delay,
     smoltcp::{Sockets, TcpStream},
@@ -30,7 +30,6 @@ use libcortex_a9::{
 };
 use libregister::RegisterR;
 use libsupport_zynq::{
-    alloc::{vec, vec::Vec},
     boot, ram,
 };
 use log::info;
@@ -181,24 +180,11 @@ pub fn main_core0() {
     println!("Eth on");
 
     const RX_LEN: usize = 8;
-    let mut rx_descs = (0..RX_LEN)
-        .map(|_| zynq::eth::rx::DescEntry::zeroed())
-        .collect::<Vec<_>>();
-    let mut rx_buffers = vec![zynq::eth::Buffer::new(); RX_LEN];
     // Number of transmission buffers (minimum is two because with
     // one, duplicate packet transmission occurs)
     const TX_LEN: usize = 8;
-    let mut tx_descs = (0..TX_LEN)
-        .map(|_| zynq::eth::tx::DescEntry::zeroed())
-        .collect::<Vec<_>>();
-    let mut tx_buffers = vec![zynq::eth::Buffer::new(); TX_LEN];
-    let eth = eth.start_rx(&mut rx_descs, &mut rx_buffers);
-    // let mut eth = eth.start_tx(&mut tx_descs, &mut tx_buffers);
-    let mut eth = eth.start_tx(
-        // HACK
-        unsafe { transmute(tx_descs.as_mut_slice()) },
-        unsafe { transmute(tx_buffers.as_mut_slice()) },
-    );
+    let eth = eth.start_rx(RX_LEN);
+    let mut eth = eth.start_tx(TX_LEN);
 
     let ethernet_addr = EthernetAddress(HWADDR);
     // IP stack

libboard_zynq/src/eth/mod.rs

@@ -263,9 +263,9 @@ impl<'r, RX, TX> Eth<'r, RX, TX> {
         });
     }
 
-    pub fn start_rx<'rx>(self, rx_list: &'rx mut [rx::DescEntry], rx_buffers: &'rx mut [Buffer]) -> Eth<'r, rx::DescList<'rx>, TX> {
+    pub fn start_rx(self, rx_size: usize) -> Eth<'r, rx::DescList, TX> {
         let new_self = Eth {
-            rx: rx::DescList::new(rx_list, rx_buffers),
+            rx: rx::DescList::new(rx_size),
             tx: self.tx,
             inner: self.inner,
             phy: self.phy,
@@ -282,10 +282,10 @@ impl<'r, RX, TX> Eth<'r, RX, TX> {
         new_self
     }
 
-    pub fn start_tx<'tx>(self, tx_list: &'tx mut [tx::DescEntry], tx_buffers: &'tx mut [Buffer]) -> Eth<'r, RX, tx::DescList<'tx>> {
+    pub fn start_tx(self, tx_size: usize) -> Eth<'r, RX, tx::DescList> {
         let new_self = Eth {
             rx: self.rx,
-            tx: tx::DescList::new(tx_list, tx_buffers),
+            tx: tx::DescList::new(tx_size),
             inner: self.inner,
             phy: self.phy,
         };
@@ -302,7 +302,7 @@ impl<'r, RX, TX> Eth<'r, RX, TX> {
     }
 }
 
-impl<'r, 'rx, TX> Eth<'r, rx::DescList<'rx>, TX> {
+impl<'r, TX> Eth<'r, rx::DescList, TX> {
     pub fn recv_next<'s: 'p, 'p>(&'s mut self) -> Result<Option<rx::PktRef<'p>>, rx::Error> {
         let status = self.inner.regs.rx_status.read();
         if status.hresp_not_ok() {
@@ -350,15 +350,15 @@ impl<'r, 'rx, TX> Eth<'r, rx::DescList<'rx>, TX> {
     }
 }
 
-impl<'r, 'tx, RX> Eth<'r, RX, tx::DescList<'tx>> {
+impl<'r, RX> Eth<'r, RX, tx::DescList> {
     pub fn send<'s: 'p, 'p>(&'s mut self, length: usize) -> Option<tx::PktRef<'p>> {
         self.tx.send(self.inner.regs, length)
     }
 }
 
-impl<'r, 'rx, 'tx: 'a, 'a> smoltcp::phy::Device<'a> for &mut Eth<'r, rx::DescList<'rx>, tx::DescList<'tx>> {
+impl<'r, 'a> smoltcp::phy::Device<'a> for &mut Eth<'r, rx::DescList, tx::DescList> {
     type RxToken = rx::PktRef<'a>;
-    type TxToken = tx::Token<'a, 'tx>;
+    type TxToken = tx::Token<'a>;
 
     fn capabilities(&self) -> smoltcp::phy::DeviceCapabilities {
         use smoltcp::phy::{DeviceCapabilities, ChecksumCapabilities, Checksum};

libboard_zynq/src/eth/rx.rs

@@ -1,4 +1,5 @@
 use core::ops::Deref;
+use alloc::{vec, vec::Vec};
 use libregister::*;
 use super::Buffer;
 
@@ -53,14 +54,18 @@ register_bit!(desc_word1, multi_hash_match, 30);
 register_bit!(desc_word1, global_broadcast, 31);
 
 #[repr(C)]
-pub struct DescList<'a> {
-    list: &'a mut [DescEntry],
-    buffers: &'a mut [Buffer],
+pub struct DescList {
+    list: Vec<DescEntry>,
+    buffers: Vec<Buffer>,
     next: usize,
 }
 
-impl<'a> DescList<'a> {
-    pub fn new(list: &'a mut [DescEntry], buffers: &'a mut [Buffer]) -> Self {
+impl DescList {
+    pub fn new(size: usize) -> Self {
+        let mut list: Vec<_> = (0..size).map(|_| DescEntry::zeroed())
+            .collect();
+        let mut buffers = vec![Buffer::new(); size];
+
         let last = list.len().min(buffers.len()) - 1;
         for (i, (entry, buffer)) in list.iter_mut().zip(buffers.iter_mut()).enumerate() {
             let is_last = i == last;
@@ -78,8 +83,7 @@ impl<'a> DescList<'a> {
         }
 
         DescList {
-            // Shorten the list of descriptors to the required number.
-            list: &mut list[0..=last],
+            list,
             buffers,
             next: 0,
         }

libboard_zynq/src/eth/tx.rs

@@ -1,4 +1,5 @@
 use core::ops::{Deref, DerefMut};
+use alloc::{vec, vec::Vec};
 use libregister::*;
 use super::{Buffer, regs};
 
@@ -40,14 +41,18 @@ impl DescEntry {
 pub const DESCS: usize = 8;
 
 #[repr(C)]
-pub struct DescList<'a> {
-    list: &'a mut [DescEntry],
-    buffers: &'a mut [Buffer],
+pub struct DescList {
+    list: Vec<DescEntry>,
+    buffers: Vec<Buffer>,
     next: usize,
 }
 
-impl<'a> DescList<'a> {
-    pub fn new(list: &'a mut [DescEntry], buffers: &'a mut [Buffer]) -> Self {
+impl DescList {
+    pub fn new(size: usize) -> Self {
+        let mut list: Vec<_> = (0..size).map(|_| DescEntry::zeroed())
+            .collect();
+        let mut buffers = vec![Buffer::new(); size];
+
         let last = list.len().min(buffers.len()) - 1;
         // Sending seems to not work properly with only one packet
         // buffer (two duplicates get send with every packet), so
@@ -73,8 +78,7 @@ impl<'a> DescList<'a> {
         }
 
         DescList {
-            // Shorten the list of descriptors to the required number.
-            list: &mut list[0..=last],
+            list,
             buffers,
             next: 0,
         }
@@ -142,12 +146,12 @@ impl<'a> DerefMut for PktRef<'a> {
 }
 
 /// TxToken for smoltcp support
-pub struct Token<'a, 'tx: 'a> {
+pub struct Token<'a> {
     pub regs: &'a mut regs::RegisterBlock,
-    pub desc_list: &'a mut DescList<'tx>,
+    pub desc_list: &'a mut DescList,
 }
 
-impl<'a, 'tx: 'a> smoltcp::phy::TxToken for Token<'a, 'tx> {
+impl<'a> smoltcp::phy::TxToken for Token<'a> {
     fn consume<R, F>(self, _timestamp: smoltcp::time::Instant, len: usize, f: F) -> smoltcp::Result<R>
         where F: FnOnce(&mut [u8]) -> smoltcp::Result<R>
     {

libboard_zynq/src/lib.rs

@@ -1,5 +1,7 @@
 #![no_std]
 
+extern crate alloc;
+
 /// Re-export so that dependents can always use the same version
 pub use smoltcp;