From cb01d0383523af4b9f80c4bdc4410791eba1173e Mon Sep 17 00:00:00 2001
From: Tyler Gilbert <tyler.w.gilbert@gmail.com>
Date: Sun, 31 Mar 2024 16:31:47 -0500
Subject: [PATCH] Add async stop() function to stm32 bdma_dma
---
embassy-stm32/src/dma/dma_bdma.rs | 63 ++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/embassy-stm32/src/dma/dma_bdma.rs b/embassy-stm32/src/dma/dma_bdma.rs
index 7b5b3cf58..a6344cf06 100644
--- a/embassy-stm32/src/dma/dma_bdma.rs
+++ b/embassy-stm32/src/dma/dma_bdma.rs
@@ -1,4 +1,4 @@
-use core::future::Future;
+use core::future::{poll_fn, Future};
use core::pin::Pin;
use core::sync::atomic::{fence, AtomicUsize, Ordering};
use core::task::{Context, Poll, Waker};
@@ -510,6 +510,31 @@ impl AnyChannel {
DmaInfo::Bdma(r) => r.ch(info.num).ndtr().read().ndt(),
}
}
+
+ fn disable_circular_mode(&self) {
+ let info = self.info();
+ match self.info().dma {
+ #[cfg(dma)]
+ DmaInfo::Dma(regs) => regs.st(info.num).cr().modify(|w| {
+ w.set_circ(false);
+ }),
+ #[cfg(bdma)]
+ DmaInfo::Bdma(regs) => regs.ch(info.num).cr().modify(|w| {
+ w.set_circ(false);
+ }),
+ }
+ }
+
+ fn poll_stop(&self) -> Poll<()> {
+ use core::sync::atomic::compiler_fence;
+ compiler_fence(Ordering::SeqCst);
+
+ if !self.is_running() {
+ Poll::Ready(())
+ } else {
+ Poll::Pending
+ }
+ }
}
/// DMA transfer.
@@ -829,6 +854,25 @@ impl<'a, W: Word> ReadableRingBuffer<'a, W> {
pub fn is_running(&mut self) -> bool {
self.channel.is_running()
}
+
+ /// Stop the DMA transfer and await until the buffer is full.
+ ///
+ /// This disables the DMA transfer's circular mode so that the transfer
+ /// stops when the buffer is full.
+ ///
+ /// This is designed to be used with streaming input data such as the
+ /// I2S/SAI or ADC.
+ ///
+ /// When using the UART, you probably want `request_stop()`.
+ pub async fn stop(&mut self) {
+ self.channel.disable_circular_mode();
+ //wait until cr.susp reads as true
+ poll_fn(|cx| {
+ self.set_waker(cx.waker());
+ self.channel.poll_stop()
+ })
+ .await
+ }
}
impl<'a, W: Word> Drop for ReadableRingBuffer<'a, W> {
@@ -940,6 +984,23 @@ impl<'a, W: Word> WritableRingBuffer<'a, W> {
pub fn is_running(&mut self) -> bool {
self.channel.is_running()
}
+
+ /// Stop the DMA transfer and await until the buffer is empty.
+ ///
+ /// This disables the DMA transfer's circular mode so that the transfer
+ /// stops when all available data has been written.
+ ///
+ /// This is designed to be used with streaming output data such as the
+ /// I2S/SAI or DAC.
+ pub async fn stop(&mut self) {
+ self.channel.disable_circular_mode();
+ //wait until cr.susp reads as true
+ poll_fn(|cx| {
+ self.set_waker(cx.waker());
+ self.channel.poll_stop()
+ })
+ .await
+ }
}
impl<'a, W: Word> Drop for WritableRingBuffer<'a, W> {