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nrf/twim: expose all functionality as inherent methods.

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This commit is contained in:
Dario Nieuwenhuis 2022-01-13 20:47:28 +01:00
parent a287fef687
commit ecb4f8fb00
3 changed files with 157 additions and 267 deletions
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420
embassy-nrf/src/twim.rs
View file

@ -201,7 +201,7 @@ impl<'d, T: Instance> Twim<'d, T> {
}
/// Get Error instance, if any occurred.
fn read_errorsrc(&self) -> Result<(), Error> {
fn check_errorsrc(&self) -> Result<(), Error> {
let r = T::regs();
let err = r.errorsrc.read();
@ -217,8 +217,26 @@ impl<'d, T: Instance> Twim<'d, T> {
Ok(())
}
fn check_rx(&self, len: usize) -> Result<(), Error> {
let r = T::regs();
if r.rxd.amount.read().bits() != len as u32 {
Err(Error::Receive)
} else {
Ok(())
}
}
fn check_tx(&self, len: usize) -> Result<(), Error> {
let r = T::regs();
if r.txd.amount.read().bits() != len as u32 {
Err(Error::Transmit)
} else {
Ok(())
}
}
/// Wait for stop or error
fn wait(&mut self) {
fn blocking_wait(&mut self) {
let r = T::regs();
loop {
if r.events_stopped.read().bits() != 0 {
@ -232,16 +250,32 @@ impl<'d, T: Instance> Twim<'d, T> {
}
}
/// Write to an I2C slave.
///
/// The buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn write(&mut self, address: u8, buffer: &[u8]) -> Result<(), Error> {
/// Wait for stop or error
fn async_wait(&mut self) -> impl Future<Output = ()> {
poll_fn(move |cx| {
let r = T::regs();
let s = T::state();
s.end_waker.register(cx.waker());
if r.events_stopped.read().bits() != 0 {
r.events_stopped.reset();
return Poll::Ready(());
}
// stop if an error occured
if r.events_error.read().bits() != 0 {
r.events_error.reset();
r.tasks_stop.write(|w| unsafe { w.bits(1) });
}
Poll::Pending
})
}
fn setup_write(&mut self, address: u8, buffer: &[u8], inten: bool) -> Result<(), Error> {
let r = T::regs();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// before any DMA action has started.
compiler_fence(SeqCst);
r.address.write(|w| unsafe { w.address().bits(address) });
@ -255,38 +289,21 @@ impl<'d, T: Instance> Twim<'d, T> {
r.events_lasttx.reset();
self.clear_errorsrc();
// Start write operation.
r.shorts.write(|w| w.lasttx_stop().enabled());
r.tasks_starttx.write(|w|
// `1` is a valid value to write to task registers.
unsafe { w.bits(1) });
self.wait();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// after all possible DMA actions have completed.
compiler_fence(SeqCst);
self.read_errorsrc()?;
if r.txd.amount.read().bits() != buffer.len() as u32 {
return Err(Error::Transmit);
if inten {
r.intenset.write(|w| w.stopped().set().error().set());
} else {
r.intenclr.write(|w| w.stopped().clear().error().clear());
}
// Start write operation.
r.shorts.write(|w| w.lasttx_stop().enabled());
r.tasks_starttx.write(|w| unsafe { w.bits(1) });
Ok(())
}
/// Read from an I2C slave.
///
/// The buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Error> {
fn setup_read(&mut self, address: u8, buffer: &mut [u8], inten: bool) -> Result<(), Error> {
let r = T::regs();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// before any DMA action has started.
compiler_fence(SeqCst);
r.address.write(|w| unsafe { w.address().bits(address) });
@ -299,44 +316,27 @@ impl<'d, T: Instance> Twim<'d, T> {
r.events_error.reset();
self.clear_errorsrc();
// Start read operation.
r.shorts.write(|w| w.lastrx_stop().enabled());
r.tasks_startrx.write(|w|
// `1` is a valid value to write to task registers.
unsafe { w.bits(1) });
self.wait();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// after all possible DMA actions have completed.
compiler_fence(SeqCst);
self.read_errorsrc()?;
if r.rxd.amount.read().bits() != buffer.len() as u32 {
return Err(Error::Receive);
if inten {
r.intenset.write(|w| w.stopped().set().error().set());
} else {
r.intenclr.write(|w| w.stopped().clear().error().clear());
}
// Start read operation.
r.shorts.write(|w| w.lastrx_stop().enabled());
r.tasks_startrx.write(|w| unsafe { w.bits(1) });
Ok(())
}
/// Write data to an I2C slave, then read data from the slave without
/// triggering a stop condition between the two.
///
/// The buffers must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn write_then_read(
fn setup_write_read(
&mut self,
address: u8,
wr_buffer: &[u8],
rd_buffer: &mut [u8],
inten: bool,
) -> Result<(), Error> {
let r = T::regs();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// before any DMA action has started.
compiler_fence(SeqCst);
r.address.write(|w| unsafe { w.address().bits(address) });
@ -352,35 +352,65 @@ impl<'d, T: Instance> Twim<'d, T> {
r.events_error.reset();
self.clear_errorsrc();
if inten {
r.intenset.write(|w| w.stopped().set().error().set());
} else {
r.intenclr.write(|w| w.stopped().clear().error().clear());
}
// Start write+read operation.
r.shorts.write(|w| {
w.lasttx_startrx().enabled();
w.lastrx_stop().enabled();
w
});
// `1` is a valid value to write to task registers.
r.tasks_starttx.write(|w| unsafe { w.bits(1) });
Ok(())
}
self.wait();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// after all possible DMA actions have completed.
/// Write to an I2C slave.
///
/// The buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn blocking_write(&mut self, address: u8, buffer: &[u8]) -> Result<(), Error> {
self.setup_write(address, buffer, false)?;
self.blocking_wait();
compiler_fence(SeqCst);
self.check_errorsrc()?;
self.check_tx(buffer.len())?;
Ok(())
}
self.read_errorsrc()?;
let bad_write = r.txd.amount.read().bits() != wr_buffer.len() as u32;
let bad_read = r.rxd.amount.read().bits() != rd_buffer.len() as u32;
if bad_write {
return Err(Error::Transmit);
}
if bad_read {
return Err(Error::Receive);
}
/// Read from an I2C slave.
///
/// The buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn blocking_read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Error> {
self.setup_read(address, buffer, false)?;
self.blocking_wait();
compiler_fence(SeqCst);
self.check_errorsrc()?;
self.check_rx(buffer.len())?;
Ok(())
}
/// Write data to an I2C slave, then read data from the slave without
/// triggering a stop condition between the two.
///
/// The buffers must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn blocking_write_read(
&mut self,
address: u8,
wr_buffer: &[u8],
rd_buffer: &mut [u8],
) -> Result<(), Error> {
self.setup_write_read(address, wr_buffer, rd_buffer, false)?;
self.blocking_wait();
compiler_fence(SeqCst);
self.check_errorsrc()?;
self.check_tx(wr_buffer.len())?;
self.check_rx(rd_buffer.len())?;
Ok(())
}
@ -388,7 +418,7 @@ impl<'d, T: Instance> Twim<'d, T> {
///
/// The write buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 1024 bytes on the nRF52840.
pub fn copy_write(&mut self, address: u8, wr_buffer: &[u8]) -> Result<(), Error> {
pub fn blocking_copy_write(&mut self, address: u8, wr_buffer: &[u8]) -> Result<(), Error> {
if wr_buffer.len() > FORCE_COPY_BUFFER_SIZE {
return Err(Error::TxBufferTooLong);
}
@ -397,7 +427,7 @@ impl<'d, T: Instance> Twim<'d, T> {
let wr_ram_buffer = &mut [0; FORCE_COPY_BUFFER_SIZE][..wr_buffer.len()];
wr_ram_buffer.copy_from_slice(wr_buffer);
self.write(address, wr_ram_buffer)
self.blocking_write(address, wr_ram_buffer)
}
/// Copy data into RAM and write to an I2C slave, then read data from the slave without
@ -408,7 +438,7 @@ impl<'d, T: Instance> Twim<'d, T> {
///
/// The read buffer must have a length of at most 255 bytes on the nRF52832
/// and at most 65535 bytes on the nRF52840.
pub fn copy_write_then_read(
pub fn blocking_copy_write_read(
&mut self,
address: u8,
wr_buffer: &[u8],
@ -422,27 +452,40 @@ impl<'d, T: Instance> Twim<'d, T> {
let wr_ram_buffer = &mut [0; FORCE_COPY_BUFFER_SIZE][..wr_buffer.len()];
wr_ram_buffer.copy_from_slice(wr_buffer);
self.write_then_read(address, wr_ram_buffer, rd_buffer)
self.blocking_write_read(address, wr_ram_buffer, rd_buffer)
}
fn wait_for_stopped_event(cx: &mut core::task::Context) -> Poll<()> {
let r = T::regs();
let s = T::state();
pub async fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Error> {
self.setup_read(address, buffer, true)?;
self.async_wait().await;
compiler_fence(SeqCst);
self.check_errorsrc()?;
self.check_rx(buffer.len())?;
Ok(())
}
s.end_waker.register(cx.waker());
if r.events_stopped.read().bits() != 0 {
r.events_stopped.reset();
pub async fn write(&mut self, address: u8, buffer: &[u8]) -> Result<(), Error> {
self.setup_write(address, buffer, true)?;
self.async_wait().await;
compiler_fence(SeqCst);
self.check_errorsrc()?;
self.check_tx(buffer.len())?;
Ok(())
}
return Poll::Ready(());
}
// stop if an error occured
if r.events_error.read().bits() != 0 {
r.events_error.reset();
r.tasks_stop.write(|w| unsafe { w.bits(1) });
}
Poll::Pending
pub async fn write_read(
&mut self,
address: u8,
wr_buffer: &[u8],
rd_buffer: &mut [u8],
) -> Result<(), Error> {
self.setup_write_read(address, wr_buffer, rd_buffer, true)?;
self.async_wait().await;
compiler_fence(SeqCst);
self.check_errorsrc()?;
self.check_tx(wr_buffer.len())?;
self.check_rx(rd_buffer.len())?;
Ok(())
}
}
@ -450,7 +493,7 @@ impl<'a, T: Instance> Drop for Twim<'a, T> {
fn drop(&mut self) {
trace!("twim drop");
// TODO when implementing async here, check for abort
// TODO: check for abort
// disable!
let r = T::regs();
@ -483,174 +526,20 @@ where
= impl Future<Output = Result<(), Self::Error>> + 'a;
fn read<'a>(&'a mut self, address: u8, buffer: &'a mut [u8]) -> Self::ReadFuture<'a> {
async move {
// NOTE: RAM slice check for buffer is not necessary, as a mutable
// slice can only be built from data located in RAM.
let r = T::regs();
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// before any DMA action has started.
compiler_fence(SeqCst);
r.address.write(|w| unsafe { w.address().bits(address) });
// Set up the DMA read.
unsafe { self.set_rx_buffer(buffer)? };
// Reset events
r.events_stopped.reset();
r.events_error.reset();
self.clear_errorsrc();
// Enable events
r.intenset.write(|w| w.stopped().set().error().set());
// Start read operation.
r.shorts.write(|w| w.lastrx_stop().enabled());
r.tasks_startrx.write(|w|
// `1` is a valid value to write to task registers.
unsafe { w.bits(1) });
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// after all possible DMA actions have completed.
compiler_fence(SeqCst);
// Wait for 'stopped' event.
poll_fn(Self::wait_for_stopped_event).await;
self.read_errorsrc()?;
if r.rxd.amount.read().bits() != buffer.len() as u32 {
return Err(Error::Receive);
}
Ok(())
}
self.read(address, buffer)
}
fn write<'a>(&'a mut self, address: u8, bytes: &'a [u8]) -> Self::WriteFuture<'a> {
async move {
slice_in_ram_or(bytes, Error::DMABufferNotInDataMemory)?;
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// before any DMA action has started.
compiler_fence(SeqCst);
let r = T::regs();
// Set up current address we're trying to talk to
r.address.write(|w| unsafe { w.address().bits(address) });
// Set up DMA write.
unsafe {
self.set_tx_buffer(bytes)?;
}
// Reset events
r.events_stopped.reset();
r.events_error.reset();
r.events_lasttx.reset();
self.clear_errorsrc();
// Enable events
r.intenset.write(|w| w.stopped().set().error().set());
// Start write operation.
r.shorts.write(|w| w.lasttx_stop().enabled());
r.tasks_starttx.write(|w|
// `1` is a valid value to write to task registers.
unsafe { w.bits(1) });
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// after all possible DMA actions have completed.
compiler_fence(SeqCst);
// Wait for 'stopped' event.
poll_fn(Self::wait_for_stopped_event).await;
self.read_errorsrc()?;
if r.txd.amount.read().bits() != bytes.len() as u32 {
return Err(Error::Transmit);
}
Ok(())
}
fn write<'a>(&'a mut self, address: u8, buffer: &'a [u8]) -> Self::WriteFuture<'a> {
self.write(address, buffer)
}
fn write_read<'a>(
&'a mut self,
address: u8,
bytes: &'a [u8],
buffer: &'a mut [u8],
wr_buffer: &'a [u8],
rd_buffer: &'a mut [u8],
) -> Self::WriteReadFuture<'a> {
async move {
slice_in_ram_or(bytes, Error::DMABufferNotInDataMemory)?;
// NOTE: RAM slice check for buffer is not necessary, as a mutable
// slice can only be built from data located in RAM.
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// before any DMA action has started.
compiler_fence(SeqCst);
let r = T::regs();
// Set up current address we're trying to talk to
r.address.write(|w| unsafe { w.address().bits(address) });
// Set up DMA buffers.
unsafe {
self.set_tx_buffer(bytes)?;
self.set_rx_buffer(buffer)?;
}
// Reset events
r.events_stopped.reset();
r.events_error.reset();
r.events_lasttx.reset();
self.clear_errorsrc();
// Enable events
r.intenset.write(|w| w.stopped().set().error().set());
// Start write+read operation.
r.shorts.write(|w| {
w.lasttx_startrx().enabled();
w.lastrx_stop().enabled();
w
});
// `1` is a valid value to write to task registers.
r.tasks_starttx.write(|w| unsafe { w.bits(1) });
// Conservative compiler fence to prevent optimizations that do not
// take in to account actions by DMA. The fence has been placed here,
// after all possible DMA actions have completed.
compiler_fence(SeqCst);
// Wait for 'stopped' event.
poll_fn(Self::wait_for_stopped_event).await;
self.read_errorsrc()?;
let bad_write = r.txd.amount.read().bits() != bytes.len() as u32;
let bad_read = r.rxd.amount.read().bits() != buffer.len() as u32;
if bad_write {
return Err(Error::Transmit);
}
if bad_read {
return Err(Error::Receive);
}
Ok(())
}
self.write_read(address, wr_buffer, rd_buffer)
}
}
@ -659,12 +548,12 @@ impl<'a, T: Instance> embedded_hal::blocking::i2c::Write for Twim<'a, T> {
fn write<'w>(&mut self, addr: u8, bytes: &'w [u8]) -> Result<(), Error> {
if slice_in_ram(bytes) {
self.write(addr, bytes)
self.blocking_write(addr, bytes)
} else {
let buf = &mut [0; FORCE_COPY_BUFFER_SIZE][..];
for chunk in bytes.chunks(FORCE_COPY_BUFFER_SIZE) {
buf[..chunk.len()].copy_from_slice(chunk);
self.write(addr, &buf[..chunk.len()])?;
self.blocking_write(addr, &buf[..chunk.len()])?;
}
Ok(())
}
@ -675,7 +564,7 @@ impl<'a, T: Instance> embedded_hal::blocking::i2c::Read for Twim<'a, T> {
type Error = Error;
fn read<'w>(&mut self, addr: u8, bytes: &'w mut [u8]) -> Result<(), Error> {
self.read(addr, bytes)
self.blocking_read(addr, bytes)
}
}
@ -689,15 +578,16 @@ impl<'a, T: Instance> embedded_hal::blocking::i2c::WriteRead for Twim<'a, T> {
buffer: &'w mut [u8],
) -> Result<(), Error> {
if slice_in_ram(bytes) {
self.write_then_read(addr, bytes, buffer)
self.blocking_write_read(addr, bytes, buffer)
} else {
self.copy_write_then_read(addr, bytes, buffer)
self.blocking_copy_write_read(addr, bytes, buffer)
}
}
}
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
#[non_exhaustive]
pub enum Error {
TxBufferTooLong,
RxBufferTooLong,

2
examples/nrf/src/bin/twim.rs
View file

@ -26,7 +26,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
info!("Reading...");
let mut buf = [0u8; 16];
unwrap!(twi.write_then_read(ADDRESS, &mut [0x00], &mut buf));
unwrap!(twi.blocking_write_read(ADDRESS, &mut [0x00], &mut buf));
info!("Read: {=[u8]:x}", buf);
}

2
examples/nrf/src/bin/twim_lowpower.rs
View file

@ -36,7 +36,7 @@ async fn main(_spawner: Spawner, mut p: Peripherals) {
info!("Reading...");
let mut buf = [0u8; 16];
unwrap!(twi.write_then_read(ADDRESS, &mut [0x00], &mut buf));
unwrap!(twi.blocking_write_read(ADDRESS, &mut [0x00], &mut buf));
info!("Read: {=[u8]:x}", buf);