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Merge pull request #1835 from oll3/fix/stm32-rng

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stm32: fix wait for RNG data
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xoviat 2023-08-28 21:38:54 +00:00 committed by GitHub
commit a4d78a6552
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1 changed files with 25 additions and 21 deletions
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46
embassy-stm32/src/rng.rs
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@ -119,7 +119,31 @@ impl<'d, T: Instance> Rng<'d, T> {
pub async fn async_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
for chunk in dest.chunks_mut(4) {
let bits = T::regs().sr().read();
let mut bits = T::regs().sr().read();
if !bits.seis() && !bits.ceis() && !bits.drdy() {
// wait for interrupt
poll_fn(|cx| {
// quick check to avoid registration if already done.
let bits = T::regs().sr().read();
if bits.drdy() || bits.seis() || bits.ceis() {
return Poll::Ready(());
}
RNG_WAKER.register(cx.waker());
T::regs().cr().modify(|reg| reg.set_ie(true));
// Need to check condition **after** `register` to avoid a race
// condition that would result in lost notifications.
let bits = T::regs().sr().read();
if bits.drdy() || bits.seis() || bits.ceis() {
Poll::Ready(())
} else {
Poll::Pending
}
})
.await;
// Re-read the status register after wait.
bits = T::regs().sr().read()
}
if bits.seis() {
// in case of noise-source or seed error we try to recover here
// but we must not use the data in DR and we return an error
@ -143,26 +167,6 @@ impl<'d, T: Instance> Rng<'d, T> {
for (dest, src) in chunk.iter_mut().zip(random_word.to_be_bytes().iter()) {
*dest = *src
}
} else {
// wait for interrupt
poll_fn(|cx| {
// quick check to avoid registration if already done.
let bits = T::regs().sr().read();
if bits.drdy() || bits.seis() || bits.ceis() {
return Poll::Ready(());
}
RNG_WAKER.register(cx.waker());
T::regs().cr().modify(|reg| reg.set_ie(true));
// Need to check condition **after** `register` to avoid a race
// condition that would result in lost notifications.
let bits = T::regs().sr().read();
if bits.drdy() || bits.seis() || bits.ceis() {
Poll::Ready(())
} else {
Poll::Pending
}
})
.await;
}
}