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stm32/dma: consolidate ringbuf

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This commit is contained in:
xoviat 2023-08-03 21:12:34 -05:00
parent 30358c435e
commit 7e269f6f17
3 changed files with 114 additions and 125 deletions
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66
embassy-stm32/src/dma/bdma.rs
View File

@ -393,6 +393,10 @@ impl<'a, C: Channel> DmaCtrl for DmaCtrlImpl<'a, C> {
fn reset_complete_count(&mut self) -> usize {
STATE.complete_count[self.0.index()].swap(0, Ordering::AcqRel)
}
fn set_waker(&mut self, waker: &Waker) {
STATE.ch_wakers[self.0.index()].register(waker);
}
}
pub struct ReadableRingBuffer<'a, C: Channel, W: Word> {
@ -463,7 +467,7 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
}
pub fn clear(&mut self) {
self.ringbuf.clear(DmaCtrlImpl(self.channel.reborrow()));
self.ringbuf.clear(&mut DmaCtrlImpl(self.channel.reborrow()));
}
/// Read elements from the ring buffer
@ -472,7 +476,7 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
/// The length remaining is the capacity, ring_buf.len(), less the elements remaining after the read
/// OverrunError is returned if the portion to be read was overwritten by the DMA controller.
pub fn read(&mut self, buf: &mut [W]) -> Result<(usize, usize), OverrunError> {
self.ringbuf.read(DmaCtrlImpl(self.channel.reborrow()), buf)
self.ringbuf.read(&mut DmaCtrlImpl(self.channel.reborrow()), buf)
}
/// Read an exact number of elements from the ringbuffer.
@ -487,29 +491,8 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
/// - If M equals N/2 or N/2 divides evenly into M, this function will return every N/2 elements read on the DMA source.
/// - Otherwise, this function may need up to N/2 extra elements to arrive before returning.
pub async fn read_exact(&mut self, buffer: &mut [W]) -> Result<usize, OverrunError> {
use core::future::poll_fn;
use core::sync::atomic::compiler_fence;
let mut read_data = 0;
let buffer_len = buffer.len();
poll_fn(|cx| {
self.set_waker(cx.waker());
compiler_fence(Ordering::SeqCst);
match self.read(&mut buffer[read_data..buffer_len]) {
Ok((len, remaining)) => {
read_data += len;
if read_data == buffer_len {
Poll::Ready(Ok(remaining))
} else {
Poll::Pending
}
}
Err(e) => Poll::Ready(Err(e)),
}
})
self.ringbuf
.read_exact(&mut DmaCtrlImpl(self.channel.reborrow()), buffer)
.await
}
@ -519,7 +502,7 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
}
pub fn set_waker(&mut self, waker: &Waker) {
STATE.ch_wakers[self.channel.index()].register(waker);
DmaCtrlImpl(self.channel.reborrow()).set_waker(waker);
}
fn clear_irqs(&mut self) {
@ -628,40 +611,19 @@ impl<'a, C: Channel, W: Word> WritableRingBuffer<'a, C, W> {
}
pub fn clear(&mut self) {
self.ringbuf.clear(DmaCtrlImpl(self.channel.reborrow()));
self.ringbuf.clear(&mut DmaCtrlImpl(self.channel.reborrow()));
}
/// Write elements to the ring buffer
/// Return a tuple of the length written and the length remaining in the buffer
pub fn write(&mut self, buf: &[W]) -> Result<(usize, usize), OverrunError> {
self.ringbuf.write(DmaCtrlImpl(self.channel.reborrow()), buf)
self.ringbuf.write(&mut DmaCtrlImpl(self.channel.reborrow()), buf)
}
/// Write an exact number of elements to the ringbuffer.
pub async fn write_exact(&mut self, buffer: &[W]) -> Result<usize, OverrunError> {
use core::future::poll_fn;
use core::sync::atomic::compiler_fence;
let mut written_data = 0;
let buffer_len = buffer.len();
poll_fn(|cx| {
self.set_waker(cx.waker());
compiler_fence(Ordering::SeqCst);
match self.write(&buffer[written_data..buffer_len]) {
Ok((len, remaining)) => {
written_data += len;
if written_data == buffer_len {
Poll::Ready(Ok(remaining))
} else {
Poll::Pending
}
}
Err(e) => Poll::Ready(Err(e)),
}
})
self.ringbuf
.write_exact(&mut DmaCtrlImpl(self.channel.reborrow()), buffer)
.await
}
@ -671,7 +633,7 @@ impl<'a, C: Channel, W: Word> WritableRingBuffer<'a, C, W> {
}
pub fn set_waker(&mut self, waker: &Waker) {
STATE.ch_wakers[self.channel.index()].register(waker);
DmaCtrlImpl(self.channel.reborrow()).set_waker(waker);
}
fn clear_irqs(&mut self) {

62
embassy-stm32/src/dma/dma.rs
View File

@ -623,6 +623,10 @@ impl<'a, C: Channel> DmaCtrl for DmaCtrlImpl<'a, C> {
fn reset_complete_count(&mut self) -> usize {
STATE.complete_count[self.0.index()].swap(0, Ordering::AcqRel)
}
fn set_waker(&mut self, waker: &Waker) {
STATE.ch_wakers[self.0.index()].register(waker);
}
}
pub struct ReadableRingBuffer<'a, C: Channel, W: Word> {
@ -708,7 +712,7 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
}
pub fn clear(&mut self) {
self.ringbuf.clear(DmaCtrlImpl(self.channel.reborrow()));
self.ringbuf.clear(&mut DmaCtrlImpl(self.channel.reborrow()));
}
/// Read elements from the ring buffer
@ -717,7 +721,7 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
/// The length remaining is the capacity, ring_buf.len(), less the elements remaining after the read
/// OverrunError is returned if the portion to be read was overwritten by the DMA controller.
pub fn read(&mut self, buf: &mut [W]) -> Result<(usize, usize), OverrunError> {
self.ringbuf.read(DmaCtrlImpl(self.channel.reborrow()), buf)
self.ringbuf.read(&mut DmaCtrlImpl(self.channel.reborrow()), buf)
}
/// Read an exact number of elements from the ringbuffer.
@ -732,29 +736,8 @@ impl<'a, C: Channel, W: Word> ReadableRingBuffer<'a, C, W> {
/// - If M equals N/2 or N/2 divides evenly into M, this function will return every N/2 elements read on the DMA source.
/// - Otherwise, this function may need up to N/2 extra elements to arrive before returning.
pub async fn read_exact(&mut self, buffer: &mut [W]) -> Result<usize, OverrunError> {
use core::future::poll_fn;
use core::sync::atomic::compiler_fence;
let mut read_data = 0;
let buffer_len = buffer.len();
poll_fn(|cx| {
self.set_waker(cx.waker());
compiler_fence(Ordering::SeqCst);
match self.read(&mut buffer[read_data..buffer_len]) {
Ok((len, remaining)) => {
read_data += len;
if read_data == buffer_len {
Poll::Ready(Ok(remaining))
} else {
Poll::Pending
}
}
Err(e) => Poll::Ready(Err(e)),
}
})
self.ringbuf
.read_exact(&mut DmaCtrlImpl(self.channel.reborrow()), buffer)
.await
}
@ -890,40 +873,19 @@ impl<'a, C: Channel, W: Word> WritableRingBuffer<'a, C, W> {
}
pub fn clear(&mut self) {
self.ringbuf.clear(DmaCtrlImpl(self.channel.reborrow()));
self.ringbuf.clear(&mut DmaCtrlImpl(self.channel.reborrow()));
}
/// Write elements from the ring buffer
/// Return a tuple of the length written and the length remaining in the buffer
pub fn write(&mut self, buf: &[W]) -> Result<(usize, usize), OverrunError> {
self.ringbuf.write(DmaCtrlImpl(self.channel.reborrow()), buf)
self.ringbuf.write(&mut DmaCtrlImpl(self.channel.reborrow()), buf)
}
/// Write an exact number of elements to the ringbuffer.
pub async fn write_exact(&mut self, buffer: &[W]) -> Result<usize, OverrunError> {
use core::future::poll_fn;
use core::sync::atomic::compiler_fence;
let mut written_data = 0;
let buffer_len = buffer.len();
poll_fn(|cx| {
self.set_waker(cx.waker());
compiler_fence(Ordering::SeqCst);
match self.write(&buffer[written_data..buffer_len]) {
Ok((len, remaining)) => {
written_data += len;
if written_data == buffer_len {
Poll::Ready(Ok(remaining))
} else {
Poll::Pending
}
}
Err(e) => Poll::Ready(Err(e)),
}
})
self.ringbuf
.write_exact(&mut DmaCtrlImpl(self.channel.reborrow()), buffer)
.await
}

103
embassy-stm32/src/dma/ringbuffer.rs
View File

@ -1,7 +1,9 @@
#![cfg_attr(gpdma, allow(unused))]
use core::future::poll_fn;
use core::ops::Range;
use core::sync::atomic::{compiler_fence, Ordering};
use core::task::{Poll, Waker};
use super::word::Word;
@ -49,6 +51,9 @@ pub trait DmaCtrl {
/// Reset the transfer completed counter to 0 and return the value just prior to the reset.
fn reset_complete_count(&mut self) -> usize;
/// Set the waker for a running poll_fn
fn set_waker(&mut self, waker: &Waker);
}
impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
@ -57,7 +62,7 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
}
/// Reset the ring buffer to its initial state
pub fn clear(&mut self, mut dma: impl DmaCtrl) {
pub fn clear(&mut self, dma: &mut impl DmaCtrl) {
self.start = 0;
dma.reset_complete_count();
}
@ -68,8 +73,43 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
}
/// The current position of the ringbuffer
fn pos(&self, remaining_transfers: usize) -> usize {
self.cap() - remaining_transfers
fn pos(&self, dma: &mut impl DmaCtrl) -> usize {
self.cap() - dma.get_remaining_transfers()
}
/// Read an exact number of elements from the ringbuffer.
///
/// Returns the remaining number of elements available for immediate reading.
/// OverrunError is returned if the portion to be read was overwritten by the DMA controller.
///
/// Async/Wake Behavior:
/// The underlying DMA peripheral only can wake us when its buffer pointer has reached the halfway point,
/// and when it wraps around. This means that when called with a buffer of length 'M', when this
/// ring buffer was created with a buffer of size 'N':
/// - If M equals N/2 or N/2 divides evenly into M, this function will return every N/2 elements read on the DMA source.
/// - Otherwise, this function may need up to N/2 extra elements to arrive before returning.
pub async fn read_exact(&mut self, dma: &mut impl DmaCtrl, buffer: &mut [W]) -> Result<usize, OverrunError> {
let mut read_data = 0;
let buffer_len = buffer.len();
poll_fn(|cx| {
dma.set_waker(cx.waker());
compiler_fence(Ordering::SeqCst);
match self.read(dma, &mut buffer[read_data..buffer_len]) {
Ok((len, remaining)) => {
read_data += len;
if read_data == buffer_len {
Poll::Ready(Ok(remaining))
} else {
Poll::Pending
}
}
Err(e) => Poll::Ready(Err(e)),
}
})
.await
}
/// Read elements from the ring buffer
@ -77,7 +117,7 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
/// If not all of the elements were read, then there will be some elements in the buffer remaining
/// The length remaining is the capacity, ring_buf.len(), less the elements remaining after the read
/// OverrunError is returned if the portion to be read was overwritten by the DMA controller.
pub fn read(&mut self, mut dma: impl DmaCtrl, buf: &mut [W]) -> Result<(usize, usize), OverrunError> {
pub fn read(&mut self, dma: &mut impl DmaCtrl, buf: &mut [W]) -> Result<(usize, usize), OverrunError> {
/*
This algorithm is optimistic: we assume we haven't overrun more than a full buffer and then check
after we've done our work to see we have. This is because on stm32, an interrupt is not guaranteed
@ -93,7 +133,7 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
rather than the data we actually copied because it costs nothing and confirms an error condition
earlier.
*/
let end = self.pos(dma.get_remaining_transfers());
let end = self.pos(dma);
if self.start == end && dma.get_complete_count() == 0 {
// No elements are available in the buffer
Ok((0, self.cap()))
@ -114,8 +154,7 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
then, get the current position of of the dma write and check
if it's inside data we could have copied
*/
let (pos, complete_count) =
critical_section::with(|_| (self.pos(dma.get_remaining_transfers()), dma.get_complete_count()));
let (pos, complete_count) = critical_section::with(|_| (self.pos(dma), dma.get_complete_count()));
if (pos >= self.start && pos < end) || (complete_count > 0 && pos >= end) || complete_count > 1 {
Err(OverrunError)
} else {
@ -141,7 +180,7 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
then, get the current position of of the dma write and check
if it's inside data we could have copied
*/
let pos = self.pos(dma.get_remaining_transfers());
let pos = self.pos(dma);
if pos > self.start || pos < end || dma.get_complete_count() > 1 {
Err(OverrunError)
} else {
@ -169,7 +208,7 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
then, get the current position of of the dma write and check
if it's inside data we could have copied
*/
let pos = self.pos(dma.get_remaining_transfers());
let pos = self.pos(dma);
if pos > self.start || pos < end || dma.reset_complete_count() > 1 {
Err(OverrunError)
} else {
@ -209,7 +248,7 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
}
/// Reset the ring buffer to its initial state
pub fn clear(&mut self, mut dma: impl DmaCtrl) {
pub fn clear(&mut self, dma: &mut impl DmaCtrl) {
self.end = 0;
dma.reset_complete_count();
}
@ -220,14 +259,39 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
}
/// The current position of the ringbuffer
fn pos(&self, remaining_transfers: usize) -> usize {
self.cap() - remaining_transfers
fn pos(&self, dma: &mut impl DmaCtrl) -> usize {
self.cap() - dma.get_remaining_transfers()
}
/// Write an exact number of elements to the ringbuffer.
pub async fn write_exact(&mut self, dma: &mut impl DmaCtrl, buffer: &[W]) -> Result<usize, OverrunError> {
let mut written_data = 0;
let buffer_len = buffer.len();
poll_fn(|cx| {
dma.set_waker(cx.waker());
compiler_fence(Ordering::SeqCst);
match self.write(dma, &buffer[written_data..buffer_len]) {
Ok((len, remaining)) => {
written_data += len;
if written_data == buffer_len {
Poll::Ready(Ok(remaining))
} else {
Poll::Pending
}
}
Err(e) => Poll::Ready(Err(e)),
}
})
.await
}
/// Write elements from the ring buffer
/// Return a tuple of the length written and the capacity remaining to be written in the buffer
pub fn write(&mut self, mut dma: impl DmaCtrl, buf: &[W]) -> Result<(usize, usize), OverrunError> {
let start = self.pos(dma.get_remaining_transfers());
pub fn write(&mut self, dma: &mut impl DmaCtrl, buf: &[W]) -> Result<(usize, usize), OverrunError> {
let start = self.pos(dma);
if start > self.end {
// The occupied portion in the ring buffer DOES wrap
let len = self.copy_from(buf, self.end..start);
@ -235,8 +299,7 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
compiler_fence(Ordering::SeqCst);
// Confirm that the DMA is not inside data we could have written
let (pos, complete_count) =
critical_section::with(|_| (self.pos(dma.get_remaining_transfers()), dma.get_complete_count()));
let (pos, complete_count) = critical_section::with(|_| (self.pos(dma), dma.get_complete_count()));
if (pos >= self.end && pos < start) || (complete_count > 0 && pos >= start) || complete_count > 1 {
Err(OverrunError)
} else {
@ -256,7 +319,7 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
compiler_fence(Ordering::SeqCst);
// Confirm that the DMA is not inside data we could have written
let pos = self.pos(dma.get_remaining_transfers());
let pos = self.pos(dma);
if pos > self.end || pos < start || dma.get_complete_count() > 1 {
Err(OverrunError)
} else {
@ -274,7 +337,7 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
compiler_fence(Ordering::SeqCst);
// Confirm that the DMA is not inside data we could have written
let pos = self.pos(dma.get_remaining_transfers());
let pos = self.pos(dma);
if pos > self.end || pos < start || dma.reset_complete_count() > 1 {
Err(OverrunError)
} else {
@ -323,7 +386,7 @@ mod tests {
requests: cell::RefCell<vec::Vec<TestCircularTransferRequest>>,
}
impl DmaCtrl for &mut TestCircularTransfer {
impl DmaCtrl for TestCircularTransfer {
fn get_remaining_transfers(&self) -> usize {
match self.requests.borrow_mut().pop().unwrap() {
TestCircularTransferRequest::PositionRequest(pos) => {
@ -350,6 +413,8 @@ mod tests {
_ => unreachable!(),
}
}
fn set_waker(&mut self, waker: &Waker) {}
}
impl TestCircularTransfer {