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cortex_a9::mutex: use AtomU32, remove powersaving behavior

Mutex works properly now.
This commit is contained in:
Astro 2019-11-18 02:37:59 +01:00
parent 4e4ff512d9
commit d89f594ba4
1 changed files with 8 additions and 22 deletions

View File

@ -1,21 +1,13 @@
use core::ops::{Deref, DerefMut};
use core::sync::atomic::{AtomicBool, Ordering};
use core::sync::atomic::{AtomicU32, Ordering};
use core::cell::UnsafeCell;
use super::asm::*;
#[inline]
fn wait_for_update() {
wfe();
}
#[inline]
fn signal_update() {
dsb();
sev();
}
const LOCKED: u32 = 1;
const UNLOCKED: u32 = 0;
pub struct Mutex<T> {
locked: AtomicBool,
locked: AtomicU32,
inner: UnsafeCell<T>,
}
@ -25,27 +17,21 @@ unsafe impl<T: Send> Send for Mutex<T> {}
impl<T> Mutex<T> {
pub const fn new(inner: T) -> Self {
Mutex{
locked: AtomicBool::new(false),
locked: AtomicU32::new(UNLOCKED),
inner: UnsafeCell::new(inner),
}
}
pub fn lock(&self) -> MutexGuard<T> {
while self.locked.compare_and_swap(false, true, Ordering::Acquire) {
while self.locked.load(Ordering::Relaxed) {
wait_for_update();
}
}
while self.locked.compare_and_swap(UNLOCKED, LOCKED, Ordering::Acquire) != UNLOCKED {}
dmb();
MutexGuard { mutex: self }
}
fn unlock(&self) {
dmb();
self.locked.store(false, Ordering::Release);
signal_update();
self.locked.store(UNLOCKED, Ordering::Release);
dsb();
}
}