diff --git a/embassy-stm32/src/dma/bdma.rs b/embassy-stm32/src/dma/bdma.rs
index a23bb8cd..88df76ba 100644
--- a/embassy-stm32/src/dma/bdma.rs
+++ b/embassy-stm32/src/dma/bdma.rs
@@ -3,18 +3,20 @@
use core::future::Future;
use core::pin::Pin;
use core::sync::atomic::{fence, Ordering};
-use core::task::{Context, Poll};
+use core::task::{Context, Poll, Waker};
+use atomic_polyfill::AtomicUsize;
use embassy_cortex_m::interrupt::Priority;
use embassy_hal_common::{into_ref, Peripheral, PeripheralRef};
use embassy_sync::waitqueue::AtomicWaker;
+use super::ringbuffer::{DmaCtrl, DmaRingBuffer, OverrunError};
use super::word::{Word, WordSize};
use super::Dir;
use crate::_generated::BDMA_CHANNEL_COUNT;
use crate::interrupt::{Interrupt, InterruptExt};
use crate::pac;
-use crate::pac::bdma::vals;
+use crate::pac::bdma::{regs, vals};
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
@@ -48,13 +50,16 @@ impl From
for vals::Dir {
struct State {
ch_wakers: [AtomicWaker; BDMA_CHANNEL_COUNT],
+ complete_count: [AtomicUsize; BDMA_CHANNEL_COUNT],
}
impl State {
const fn new() -> Self {
+ const ZERO: AtomicUsize = AtomicUsize::new(0);
const AW: AtomicWaker = AtomicWaker::new();
Self {
ch_wakers: [AW; BDMA_CHANNEL_COUNT],
+ complete_count: [ZERO; BDMA_CHANNEL_COUNT],
}
}
}
@@ -105,8 +110,23 @@ pub(crate) unsafe fn on_irq_inner(dma: pac::bdma::Dma, channel_num: usize, index
if isr.teif(channel_num) {
panic!("DMA: error on BDMA@{:08x} channel {}", dma.0 as u32, channel_num);
}
+
+ let mut wake = false;
+
+ if isr.htif(channel_num) && cr.read().htie() {
+ // Acknowledge half transfer complete interrupt
+ dma.ifcr().write(|w| w.set_htif(channel_num, true));
+ wake = true;
+ }
+
if isr.tcif(channel_num) && cr.read().tcie() {
- cr.write(|_| ()); // Disable channel interrupts with the default value.
+ // Acknowledge transfer complete interrupt
+ dma.ifcr().write(|w| w.set_tcif(channel_num, true));
+ STATE.complete_count[index].fetch_add(1, Ordering::Release);
+ wake = true;
+ }
+
+ if wake {
STATE.ch_wakers[index].wake();
}
}
@@ -252,6 +272,7 @@ impl<'a, C: Channel> Transfer<'a, C> {
let mut this = Self { channel };
this.clear_irqs();
+ STATE.complete_count[this.channel.index()].store(0, Ordering::Release);
#[cfg(dmamux)]
super::dmamux::configure_dmamux(&mut *this.channel, _request);
@@ -299,7 +320,9 @@ impl<'a, C: Channel> Transfer<'a, C> {
pub fn is_running(&mut self) -> bool {
let ch = self.channel.regs().ch(self.channel.num());
- unsafe { ch.cr().read() }.en()
+ let en = unsafe { ch.cr().read() }.en();
+ let tcif = STATE.complete_count[self.channel.index()].load(Ordering::Acquire) != 0;
+ en && !tcif
}
/// Gets the total remaining transfers for the channel
@@ -342,3 +365,159 @@ impl<'a, C: Channel> Future for Transfer<'a, C> {
}
}
}
+
+// ==============================
+
+impl DmaCtrl for C {
+ fn ndtr(&self) -> usize {
+ let ch = self.regs().ch(self.num());
+ unsafe { ch.ndtr().read() }.ndt() as usize
+ }
+
+ fn get_complete_count(&self) -> usize {
+ STATE.complete_count[self.index()].load(Ordering::Acquire)
+ }
+
+ fn reset_complete_count(&mut self) -> usize {
+ STATE.complete_count[self.index()].swap(0, Ordering::AcqRel)
+ }
+}
+
+pub struct RingBuffer<'a, C: Channel, W: Word> {
+ cr: regs::Cr,
+ channel: PeripheralRef<'a, C>,
+ ringbuf: DmaRingBuffer<'a, W>,
+}
+
+impl<'a, C: Channel, W: Word> RingBuffer<'a, C, W> {
+ pub unsafe fn new_read(
+ channel: impl Peripheral + 'a,
+ _request: Request,
+ peri_addr: *mut W,
+ buffer: &'a mut [W],
+ _options: TransferOptions,
+ ) -> Self {
+ into_ref!(channel);
+
+ let len = buffer.len();
+ assert!(len > 0 && len <= 0xFFFF);
+
+ let dir = Dir::PeripheralToMemory;
+ let data_size = W::size();
+
+ let channel_number = channel.num();
+ let dma = channel.regs();
+
+ // "Preceding reads and writes cannot be moved past subsequent writes."
+ fence(Ordering::SeqCst);
+
+ #[cfg(bdma_v2)]
+ critical_section::with(|_| channel.regs().cselr().modify(|w| w.set_cs(channel.num(), _request)));
+
+ let mut w = regs::Cr(0);
+ w.set_psize(data_size.into());
+ w.set_msize(data_size.into());
+ w.set_minc(vals::Inc::ENABLED);
+ w.set_dir(dir.into());
+ w.set_teie(true);
+ w.set_htie(true);
+ w.set_tcie(true);
+ w.set_circ(vals::Circ::ENABLED);
+ w.set_pl(vals::Pl::VERYHIGH);
+ w.set_en(true);
+
+ let buffer_ptr = buffer.as_mut_ptr();
+ let mut this = Self {
+ channel,
+ cr: w,
+ ringbuf: DmaRingBuffer::new(buffer),
+ };
+ this.clear_irqs();
+
+ #[cfg(dmamux)]
+ super::dmamux::configure_dmamux(&mut *this.channel, _request);
+
+ let ch = dma.ch(channel_number);
+ ch.par().write_value(peri_addr as u32);
+ ch.mar().write_value(buffer_ptr as u32);
+ ch.ndtr().write(|w| w.set_ndt(len as u16));
+
+ this
+ }
+
+ pub fn start(&mut self) {
+ let ch = self.channel.regs().ch(self.channel.num());
+ unsafe { ch.cr().write_value(self.cr) }
+ }
+
+ pub fn clear(&mut self) {
+ self.ringbuf.clear(&mut *self.channel);
+ }
+
+ /// Read bytes from the ring buffer
+ /// OverrunError is returned if the portion to be read was overwritten by the DMA controller.
+ pub fn read(&mut self, buf: &mut [W]) -> Result {
+ self.ringbuf.read(&mut *self.channel, buf)
+ }
+
+ pub fn is_empty(&self) -> bool {
+ self.ringbuf.is_empty()
+ }
+
+ pub fn len(&self) -> usize {
+ self.ringbuf.len()
+ }
+
+ pub fn capacity(&self) -> usize {
+ self.ringbuf.dma_buf.len()
+ }
+
+ pub fn set_waker(&mut self, waker: &Waker) {
+ STATE.ch_wakers[self.channel.index()].register(waker);
+ }
+
+ fn clear_irqs(&mut self) {
+ let dma = self.channel.regs();
+ unsafe {
+ dma.ifcr().write(|w| {
+ w.set_htif(self.channel.num(), true);
+ w.set_tcif(self.channel.num(), true);
+ w.set_teif(self.channel.num(), true);
+ })
+ }
+ }
+
+ pub fn request_stop(&mut self) {
+ let ch = self.channel.regs().ch(self.channel.num());
+
+ // Disable the channel. Keep the IEs enabled so the irqs still fire.
+ unsafe {
+ ch.cr().write(|w| {
+ w.set_teie(true);
+ w.set_htie(true);
+ w.set_tcie(true);
+ })
+ }
+ }
+
+ pub fn is_running(&mut self) -> bool {
+ let ch = self.channel.regs().ch(self.channel.num());
+ unsafe { ch.cr().read() }.en()
+ }
+
+ /// Synchronize the position of the ring buffer to the actual DMA controller position
+ pub fn reload_position(&mut self) {
+ let ch = self.channel.regs().ch(self.channel.num());
+ self.ringbuf.ndtr = unsafe { ch.ndtr().read() }.ndt() as usize;
+ }
+}
+
+impl<'a, C: Channel, W: Word> Drop for RingBuffer<'a, C, W> {
+ fn drop(&mut self) {
+ self.request_stop();
+ while self.is_running() {}
+
+ // "Subsequent reads and writes cannot be moved ahead of preceding reads."
+ fence(Ordering::SeqCst);
+ }
+}