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STM32 BDMA: Use interrupt flags instead of atomics

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This commit is contained in:
Timo Kröger
2021-07-22 14:52:16 +02:00
committed by Dario Nieuwenhuis
parent 5a4a5ce334
commit 43c4f24207
1 changed files with 22 additions and 30 deletions
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52
embassy-stm32/src/dma/bdma.rs
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@@ -3,7 +3,6 @@
use core::future::Future;
use core::task::Poll;
use atomic_polyfill::{AtomicU8, Ordering};
use embassy::interrupt::{Interrupt, InterruptExt};
use embassy::util::{AtomicWaker, OnDrop};
use futures::future::poll_fn;
@@ -15,22 +14,16 @@ use crate::pac::bdma::vals;
use crate::rcc::sealed::RccPeripheral;
const CH_COUNT: usize = pac::peripheral_count!(bdma) * 8;
const CH_STATUS_NONE: u8 = 0;
const CH_STATUS_COMPLETED: u8 = 1;
const CH_STATUS_ERROR: u8 = 2;
struct State {
ch_wakers: [AtomicWaker; CH_COUNT],
ch_status: [AtomicU8; CH_COUNT],
}
impl State {
const fn new() -> Self {
const AW: AtomicWaker = AtomicWaker::new();
const AU: AtomicU8 = AtomicU8::new(CH_STATUS_NONE);
Self {
ch_wakers: [AW; CH_COUNT],
ch_status: [AU; CH_COUNT],
}
}
}
@@ -57,21 +50,17 @@ pub(crate) unsafe fn do_transfer(
let ch = dma.ch(channel_number as _);
// Reset status
// Generate a DMB here to flush the store buffer (M7) before enabling the DMA
STATE.ch_status[state_number as usize].store(CH_STATUS_NONE, Ordering::Release);
dma.ifcr().write(|w| {
w.set_tcif(channel_number as _, true);
w.set_teif(channel_number as _, true);
});
let on_drop = OnDrop::new(move || unsafe {
ch.cr().modify(|w| {
w.set_tcie(false);
w.set_teie(false);
w.set_en(false);
});
while ch.cr().read().en() {}
// Disable the channel and interrupts with the default value.
ch.cr().write(|_| ());
// Disabling the DMA mid transfer might cause some flags to be set, clear them all for the
// next transfer
dma.ifcr()
.write(|w| w.set_gif(channel_number as usize, true));
// Wait for the transfer to complete when it was ongoing.
while ch.cr().read().en() {}
});
#[cfg(dmamux)]
@@ -103,15 +92,20 @@ pub(crate) unsafe fn do_transfer(
async move {
let res = poll_fn(|cx| {
STATE.ch_wakers[state_number as usize].register(cx.waker());
match STATE.ch_status[state_number as usize].load(Ordering::Acquire) {
CH_STATUS_NONE => Poll::Pending,
x => Poll::Ready(x),
let isr = dma.isr().read();
// TODO handle error
assert!(!isr.teif(channel_number as _));
if isr.tcif(channel_number as _) {
Poll::Ready(())
} else {
Poll::Pending
}
})
.await;
// TODO handle error
assert!(res == CH_STATUS_COMPLETED);
drop(on_drop)
}
}
@@ -136,12 +130,10 @@ unsafe fn on_irq() {
let dman = dma_num!($dma);
for chn in 0..crate::pac::dma_channels_count!($dma) {
let n = dman * 8 + chn;
if isr.teif(chn) {
STATE.ch_status[n].store(CH_STATUS_ERROR, Ordering::Relaxed);
STATE.ch_wakers[n].wake();
} else if isr.tcif(chn) {
STATE.ch_status[n].store(CH_STATUS_COMPLETED, Ordering::Relaxed);
let cr = pac::$dma.ch(chn).cr();
if isr.tcif(chn) && cr.read().tcie() {
cr.write(|_| ()); // Disable channel interrupts with the default value.
let n = dma_num!($dma) * 8 + chn;
STATE.ch_wakers[n].wake();
}
}