M-Labs/zynq-rs
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zynq::eth: remove all memory barriers

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They were not the solution.
This commit is contained in:
Astro 2019-11-10 23:47:56 +01:00
parent afd96bd887
commit cae02947bc
2 changed files with 0 additions and 18 deletions
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8
src/zynq/eth/rx.rs
View File

@ -3,8 +3,6 @@ use vcell::VolatileCell;
use crate::{register, register_bit, register_bits, regs::*};
use super::MTU;
use crate::cortex_a9::asm;
#[derive(Debug)]
pub enum Error {
HrespNotOk,
@ -79,8 +77,6 @@ impl<'a> DescList<'a> {
DescWord1::zeroed()
);
}
// Ensure descriptors get written before they are read.
asm::dmb();
DescList {
// Shorten the list of descriptors to the required number.
@ -100,7 +96,6 @@ impl<'a> DescList<'a> {
if entry.word0.read().used() {
let word1 = entry.word1.read();
let len = word1.frame_length_lsbs().into();
asm::dmb();
let buffer = &mut self.buffers[self.next][0..len];
self.next += 1;
@ -128,9 +123,6 @@ pub struct PktRef<'a> {
impl<'a> Drop for PktRef<'a> {
fn drop(&mut self) {
// Ensure that any buffer reads have finished before we
// release the buffer to the hardware.
asm::dmb();
self.entry.word0.modify(|_, w| w.used(false));
}
}

10
src/zynq/eth/tx.rs
View File

@ -1,7 +1,6 @@
use core::ops::{Deref, DerefMut};
use vcell::VolatileCell;
use crate::{register, register_bit, register_bits, regs::*};
use crate::cortex_a9::asm;
use super::{MTU, regs};
/// Descriptor entry
@ -73,8 +72,6 @@ impl<'a> DescList<'a> {
.last_buffer(true)
);
}
// Ensure the descriptor words get written before they are read.
asm::dsb();
DescList {
// Shorten the list of descriptors to the required number.
@ -123,14 +120,7 @@ pub struct PktRef<'a> {
impl<'a> Drop for PktRef<'a> {
fn drop(&mut self) {
// Ensure that all writes to the buffer have finished before
// they are read again.
asm::dmb();
self.entry.word1.modify(|_, w| w.used(false));
// Ensure that the descriptor write has finished before it is
// read again, and (by DSB, not just DMB) that it has been
// written before the register access.
asm::dsb();
if ! self.regs.tx_status.read().tx_go() {
self.regs.net_ctrl.modify(|_, w|
w.start_tx(true)