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simplify and rename ringbuffer methods, make len available

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This commit is contained in:
Alexandros Liarokapis 2024-09-23 02:01:44 +03:00
parent 2b10caafd4
commit f4ec0cb4d4
1 changed files with 43 additions and 49 deletions
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92
embassy-stm32/src/dma/ringbuffer/mod.rs
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@ -27,10 +27,6 @@ struct DmaIndex {
pos: usize,
}
fn pos(cap: usize, dma: &impl DmaCtrl) -> usize {
cap - dma.get_remaining_transfers()
}
impl DmaIndex {
fn reset(&mut self) {
self.pos = 0;
@ -42,9 +38,9 @@ impl DmaIndex {
}
fn dma_sync(&mut self, cap: usize, dma: &mut impl DmaCtrl) {
let fst_pos = pos(cap, dma);
let fst_pos = cap - dma.get_remaining_transfers();
let fst_count = dma.reset_complete_count();
let pos = pos(cap, dma);
let pos = cap - dma.get_remaining_transfers();
let wrap_count = if pos >= fst_pos {
fst_count
@ -68,8 +64,7 @@ impl DmaIndex {
rhs.completion_count -= min_count;
}
fn diff(&mut self, cap: usize, rhs: &mut DmaIndex) -> isize {
Self::normalize(self, rhs);
fn diff(&self, cap: usize, rhs: &DmaIndex) -> isize {
(self.completion_count * cap + self.pos) as isize - (rhs.completion_count * cap + rhs.pos) as isize
}
}
@ -94,26 +89,39 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
pub fn clear(&mut self, dma: &mut impl DmaCtrl) {
dma.reset_complete_count();
self.write_index.reset();
self.update_dma_index(dma);
self.write_index.dma_sync(self.cap(), dma);
self.read_index = self.write_index;
}
/// The capacity of the ringbuffer
/// Get the full ringbuffer capacity.
pub const fn cap(&self) -> usize {
self.dma_buf.len()
}
/// Get the available readable dma samples.
pub fn len(&self) -> Result<usize, OverrunError> {
let diff: usize = self.write_index.diff(self.cap(), &self.read_index).try_into().unwrap();
if diff > self.cap() {
Err(OverrunError)
} else {
Ok(diff)
}
}
/// Read elements from the ring buffer
/// Return a tuple of the length read and the length remaining in the buffer
/// 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, dma: &mut impl DmaCtrl, buf: &mut [W]) -> Result<(usize, usize), OverrunError> {
let readable = self.margin(dma)?.min(buf.len());
self.sync_write_index(dma);
let readable = self.len()?.min(buf.len());
for i in 0..readable {
buf[i] = self.read_buf(i);
}
let available = self.margin(dma)?;
self.sync_write_index(dma);
let available = self.len()?;
self.read_index.advance(self.cap(), readable);
Ok((readable, available - readable))
}
@ -151,10 +159,6 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
.await
}
fn update_dma_index(&mut self, dma: &mut impl DmaCtrl) {
self.write_index.dma_sync(self.cap(), dma)
}
fn read_buf(&self, offset: usize) -> W {
unsafe {
core::ptr::read_volatile(
@ -165,21 +169,9 @@ impl<'a, W: Word> ReadableDmaRingBuffer<'a, W> {
}
}
/// Returns available dma samples
fn margin(&mut self, dma: &mut impl DmaCtrl) -> Result<usize, OverrunError> {
self.update_dma_index(dma);
let diff: usize = self
.write_index
.diff(self.cap(), &mut self.read_index)
.try_into()
.unwrap();
if diff > self.cap() {
Err(OverrunError)
} else {
Ok(diff)
}
fn sync_write_index(&mut self, dma: &mut impl DmaCtrl) {
self.write_index.dma_sync(self.cap(), dma);
DmaIndex::normalize(&mut self.write_index, &mut self.read_index);
}
}
@ -207,12 +199,23 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
pub fn clear(&mut self, dma: &mut impl DmaCtrl) {
dma.reset_complete_count();
self.read_index.reset();
self.update_dma_index(dma);
self.read_index.dma_sync(self.cap(), dma);
self.write_index = self.read_index;
self.write_index.advance(self.cap(), self.cap());
}
/// Get the capacity of the ringbuffer.
/// Get the remaining writable dma samples.
pub fn len(&self) -> Result<usize, OverrunError> {
let diff = self.write_index.diff(self.cap(), &self.read_index);
if diff < 0 {
Err(OverrunError)
} else {
Ok(self.cap().saturating_sub(diff as usize))
}
}
/// Get the full ringbuffer capacity.
pub const fn cap(&self) -> usize {
self.dma_buf.len()
}
@ -220,11 +223,13 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
/// Append data to the ring buffer.
/// Returns a tuple of the data written and the remaining write capacity in the buffer.
pub fn write(&mut self, dma: &mut impl DmaCtrl, buf: &[W]) -> Result<(usize, usize), OverrunError> {
let writable = self.margin(dma)?.min(buf.len());
self.sync_read_index(dma);
let writable = self.len()?.min(buf.len());
for i in 0..writable {
self.write_buf(i, buf[i]);
}
let available = self.margin(dma)?;
self.sync_read_index(dma);
let available = self.len()?;
self.write_index.advance(self.cap(), writable);
Ok((writable, available - writable))
}
@ -261,10 +266,6 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
.await
}
fn update_dma_index(&mut self, dma: &mut impl DmaCtrl) {
self.read_index.dma_sync(self.cap(), dma);
}
fn write_buf(&mut self, offset: usize, value: W) {
unsafe {
core::ptr::write_volatile(
@ -276,16 +277,9 @@ impl<'a, W: Word> WritableDmaRingBuffer<'a, W> {
}
}
fn margin(&mut self, dma: &mut impl DmaCtrl) -> Result<usize, OverrunError> {
self.update_dma_index(dma);
let diff = self.write_index.diff(self.cap(), &mut self.read_index);
if diff < 0 {
Err(OverrunError)
} else {
Ok(self.cap().saturating_sub(diff as usize))
}
fn sync_read_index(&mut self, dma: &mut impl DmaCtrl) {
self.read_index.dma_sync(self.cap(), dma);
DmaIndex::normalize(&mut self.read_index, &mut self.write_index);
}
}