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Spi with 16bit framesize #258

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merged 8 commits into from
Aug 31, 2020
Merged

Spi with 16bit framesize #258

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3c975a5
separated 8 and 16b dataframe operation
unpaid-bill Aug 17, 2020
cd382bc
added conversion from 16b to 8b spi dataframe
unpaid-bill Aug 17, 2020
603d0c6
minor code cleanup
unpaid-bill Aug 17, 2020
4fb6d5a
added SpiReadWrite trait to reduce duplicate code
unpaid-bill Aug 25, 2020
4fc7d8a
cargo fmt and minor documentation additions
unpaid-bill Aug 25, 2020
41d3605
updated CHANGELOG.md
unpaid-bill Aug 30, 2020
728b2b3
document breaking change in CHANGELOG.md
unpaid-bill Aug 30, 2020
cc2b9be
renamed fast_write to spi_write
unpaid-bill Aug 31, 2020
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211 changes: 149 additions & 62 deletions src/spi.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -109,10 +109,11 @@ pins_impl!(
(MISO, SCK, MOSI), (Miso, Sck, Mosi), (_Miso, _Sck, _Mosi);
);

pub struct Spi<SPI, REMAP, PINS> {
pub struct Spi<SPI, REMAP, PINS, FRAMESIZE> {
spi: SPI,
pins: PINS,
_remap: PhantomData<REMAP>,
_framesize: PhantomData<FRAMESIZE>,
}

/// A filler type for when the SCK pin is unnecessary
Expand Down Expand Up @@ -147,9 +148,9 @@ remap!(Spi3NoRemap, SPI3, false, PB3, PB4, PB5);
#[cfg(feature = "connectivity")]
remap!(Spi3Remap, SPI3, true, PC10, PC11, PC12);

impl<REMAP, PINS> Spi<SPI1, REMAP, PINS> {
impl<REMAP, PINS> Spi<SPI1, REMAP, PINS, u8> {
/**
Constructs an SPI instance using SPI1.
Constructs an SPI instance using SPI1 in 8bit dataframe mode.

The pin parameter tuple (sck, miso, mosi) should be `(PA5, PA6, PA7)` or `(PB3, PB4, PB5)` configured as `(Alternate<PushPull>, Input<Floating>, Alternate<PushPull>)`.

Expand All @@ -170,13 +171,13 @@ impl<REMAP, PINS> Spi<SPI1, REMAP, PINS> {
PINS: Pins<REMAP, POS>,
{
mapr.modify_mapr(|_, w| w.spi1_remap().bit(REMAP::REMAP));
Spi::<SPI1, _, _>::_spi(spi, pins, mode, freq.into(), clocks, apb)
Spi::<SPI1, _, _, u8>::_spi(spi, pins, mode, freq.into(), clocks, apb)
}
}

impl<REMAP, PINS> Spi<SPI2, REMAP, PINS> {
impl<REMAP, PINS> Spi<SPI2, REMAP, PINS, u8> {
/**
Constructs an SPI instance using SPI2.
Constructs an SPI instance using SPI2 in 8bit dataframe mode.

The pin parameter tuple (sck, miso, mosi) should be `(PB13, PB14, PB15)` configured as `(Alternate<PushPull>, Input<Floating>, Alternate<PushPull>)`.

Expand All @@ -195,14 +196,14 @@ impl<REMAP, PINS> Spi<SPI2, REMAP, PINS> {
REMAP: Remap<Periph = SPI2>,
PINS: Pins<REMAP, POS>,
{
Spi::<SPI2, _, _>::_spi(spi, pins, mode, freq.into(), clocks, apb)
Spi::<SPI2, _, _, u8>::_spi(spi, pins, mode, freq.into(), clocks, apb)
}
}

#[cfg(any(feature = "high", feature = "connectivity"))]
impl<REMAP, PINS> Spi<SPI3, REMAP, PINS> {
impl<REMAP, PINS> Spi<SPI3, REMAP, PINS, u8> {
/**
Constructs an SPI instance using SPI3.
Constructs an SPI instance using SPI3 in 8bit dataframe mode.

The pin parameter tuple (sck, miso, mosi) should be `(PB3, PB4, PB5)` or `(PC10, PC11, PC12)` configured as `(Alternate<PushPull>, Input<Floating>, Alternate<PushPull>)`.

Expand All @@ -221,13 +222,94 @@ impl<REMAP, PINS> Spi<SPI3, REMAP, PINS> {
REMAP: Remap<Periph = SPI3>,
PINS: Pins<REMAP, POS>,
{
Spi::<SPI3, _, _>::_spi(spi, pins, mode, freq.into(), clocks, apb)
Spi::<SPI3, _, _, u8>::_spi(spi, pins, mode, freq.into(), clocks, apb)
}
}

pub type SpiRegisterBlock = crate::pac::spi1::RegisterBlock;

impl<SPI, REMAP, PINS> Spi<SPI, REMAP, PINS>
pub trait SpiReadWrite<T> {
fn read_data_reg(&mut self) -> T;
fn write_data_reg(&mut self, data: T);
fn write_fast(&mut self, words: &[T]) -> Result<(), Error>;
}

impl<SPI, REMAP, PINS, FrameSize> SpiReadWrite<FrameSize> for Spi<SPI, REMAP, PINS, FrameSize>
where
SPI: Deref<Target = SpiRegisterBlock>,
FrameSize: Copy,
{
fn read_data_reg(&mut self) -> FrameSize {
// NOTE(read_volatile) read only 1 byte (the svd2rust API only allows
// reading a half-word)
return unsafe { ptr::read_volatile(&self.spi.dr as *const _ as *const FrameSize) };
}

fn write_data_reg(&mut self, data: FrameSize) {
// NOTE(write_volatile) see note above
unsafe { ptr::write_volatile(&self.spi.dr as *const _ as *mut FrameSize, data) }
}

// Implement write as per the "Transmit only procedure" page 712
// of RM0008 Rev 20. This is more than twice as fast as the
// default Write<> implementation (which reads and drops each
// received value)
fn write_fast(&mut self, words: &[FrameSize]) -> Result<(), Error> {
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Since we don't have a write_slow or similar, I think we could rename this to just write as it is currently, and remove the point in the comment about this being faster than something else.

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I was thinking to differentiate it from the embedded_hal::blocking::spi::Write<T> function fn write(&mut self, words: &[T]), which calls write_fast(). There is a naming conflict if they're both named write. Perhaps spi_write or something similar would be more appropriate?

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Oh right, that's a good point. I think spi_write might be a bit clearer.

// Write each word when the tx buffer is empty
for word in words {
loop {
let sr = self.spi.sr.read();
if sr.txe().bit_is_set() {
// NOTE(write_volatile) see note above
// unsafe { ptr::write_volatile(&self.spi.dr as *const _ as *mut u8, *word) }
self.write_data_reg(*word);
if sr.modf().bit_is_set() {
return Err(Error::ModeFault);
}
break;
}
}
}
// Wait for final TXE
loop {
let sr = self.spi.sr.read();
if sr.txe().bit_is_set() {
break;
}
}
// Wait for final !BSY
loop {
let sr = self.spi.sr.read();
if !sr.bsy().bit_is_set() {
break;
}
}
// Clear OVR set due to dropped received values
// NOTE(read_volatile) see note above
// unsafe {
// let _ = ptr::read_volatile(&self.spi.dr as *const _ as *const u8);
// }
let _ = self.read_data_reg();
let _ = self.spi.sr.read();
Ok(())
}
}

impl<SPI, REMAP, PINS, FrameSize> Spi<SPI, REMAP, PINS, FrameSize>
where
SPI: Deref<Target = SpiRegisterBlock>,
FrameSize: Copy,
{
#[deprecated(since = "0.6.0", note = "Please use release instead")]
pub fn free(self) -> (SPI, PINS) {
self.release()
}
pub fn release(self) -> (SPI, PINS) {
(self.spi, self.pins)
}
}

impl<SPI, REMAP, PINS> Spi<SPI, REMAP, PINS, u8>
where
SPI: Deref<Target = SpiRegisterBlock> + Enable + Reset,
SPI::Bus: GetBusFreq,
Expand Down Expand Up @@ -300,25 +382,50 @@ where
spi,
pins,
_remap: PhantomData,
_framesize: PhantomData,
}
}

#[deprecated(since = "0.6.0", note = "Please use release instead")]
pub fn free(self) -> (SPI, PINS) {
self.release()
/// Converts from 8bit dataframe to 16bit.
pub fn frame_size_16bit(self) -> Spi<SPI, REMAP, PINS, u16> {
self.spi.cr1.modify(|_, w| w.spe().clear_bit());
self.spi.cr1.modify(|_, w| w.dff().set_bit());
self.spi.cr1.modify(|_, w| w.spe().set_bit());
Spi {
spi: self.spi,
pins: self.pins,
_remap: PhantomData,
_framesize: PhantomData,
}
}
pub fn release(self) -> (SPI, PINS) {
(self.spi, self.pins)
}

impl<SPI, REMAP, PINS> Spi<SPI, REMAP, PINS, u16>
where
SPI: Deref<Target = SpiRegisterBlock>,
{
/// Converts from 16bit dataframe to 8bit.
pub fn frame_size_8bit(self) -> Spi<SPI, REMAP, PINS, u8> {
self.spi.cr1.modify(|_, w| w.spe().clear_bit());
self.spi.cr1.modify(|_, w| w.dff().clear_bit());
self.spi.cr1.modify(|_, w| w.spe().set_bit());
Spi {
spi: self.spi,
pins: self.pins,
_remap: PhantomData,
_framesize: PhantomData,
}
}
}

impl<SPI, REMAP, PINS> crate::hal::spi::FullDuplex<u8> for Spi<SPI, REMAP, PINS>
impl<SPI, REMAP, PINS, FrameSize> crate::hal::spi::FullDuplex<FrameSize>
for Spi<SPI, REMAP, PINS, FrameSize>
where
SPI: Deref<Target = SpiRegisterBlock>,
FrameSize: Copy,
{
type Error = Error;

fn read(&mut self) -> nb::Result<u8, Error> {
fn read(&mut self) -> nb::Result<FrameSize, Error> {
let sr = self.spi.sr.read();

Err(if sr.ovr().bit_is_set() {
Expand All @@ -330,13 +437,13 @@ where
} else if sr.rxne().bit_is_set() {
// NOTE(read_volatile) read only 1 byte (the svd2rust API only allows
// reading a half-word)
return Ok(unsafe { ptr::read_volatile(&self.spi.dr as *const _ as *const u8) });
return Ok(self.read_data_reg());
} else {
nb::Error::WouldBlock
})
}

fn send(&mut self, byte: u8) -> nb::Result<(), Error> {
fn send(&mut self, data: FrameSize) -> nb::Result<(), Error> {
let sr = self.spi.sr.read();

Err(if sr.ovr().bit_is_set() {
Expand All @@ -347,20 +454,23 @@ where
nb::Error::Other(Error::Crc)
} else if sr.txe().bit_is_set() {
// NOTE(write_volatile) see note above
unsafe { ptr::write_volatile(&self.spi.dr as *const _ as *mut u8, byte) }
self.write_data_reg(data);
return Ok(());
} else {
nb::Error::WouldBlock
})
}
}

impl<SPI, REMAP, PINS> crate::hal::blocking::spi::transfer::Default<u8> for Spi<SPI, REMAP, PINS> where
SPI: Deref<Target = SpiRegisterBlock>
impl<SPI, REMAP, PINS, FrameSize> crate::hal::blocking::spi::transfer::Default<FrameSize>
for Spi<SPI, REMAP, PINS, FrameSize>
where
SPI: Deref<Target = SpiRegisterBlock>,
FrameSize: Copy,
{
}

impl<SPI, REMAP, PINS> crate::hal::blocking::spi::Write<u8> for Spi<SPI, REMAP, PINS>
impl<SPI, REMAP, PINS> crate::hal::blocking::spi::Write<u8> for Spi<SPI, REMAP, PINS, u8>
where
SPI: Deref<Target = SpiRegisterBlock>,
{
Expand All @@ -371,48 +481,25 @@ where
// default Write<> implementation (which reads and drops each
// received value)
fn write(&mut self, words: &[u8]) -> Result<(), Error> {
// Write each word when the tx buffer is empty
for word in words {
loop {
let sr = self.spi.sr.read();
if sr.txe().bit_is_set() {
// NOTE(write_volatile) see note above
unsafe { ptr::write_volatile(&self.spi.dr as *const _ as *mut u8, *word) }
if sr.modf().bit_is_set() {
return Err(Error::ModeFault);
}
break;
}
}
}
// Wait for final TXE
loop {
let sr = self.spi.sr.read();
if sr.txe().bit_is_set() {
break;
}
}
// Wait for final !BSY
loop {
let sr = self.spi.sr.read();
if !sr.bsy().bit_is_set() {
break;
}
}
// Clear OVR set due to dropped received values
// NOTE(read_volatile) see note above
unsafe {
let _ = ptr::read_volatile(&self.spi.dr as *const _ as *const u8);
}
let _ = self.spi.sr.read();
Ok(())
self.write_fast(words)
}
}

impl<SPI, REMAP, PINS> crate::hal::blocking::spi::Write<u16> for Spi<SPI, REMAP, PINS, u16>
where
SPI: Deref<Target = SpiRegisterBlock>,
{
type Error = Error;

fn write(&mut self, words: &[u16]) -> Result<(), Error> {
self.write_fast(words)
}
}

// DMA

pub struct SpiPayload<SPI, REMAP, PINS> {
spi: Spi<SPI, REMAP, PINS>,
spi: Spi<SPI, REMAP, PINS, u8>,
}

pub type SpiTxDma<SPI, REMAP, PINS, CHANNEL> = TxDma<SpiPayload<SPI, REMAP, PINS>, CHANNEL>;
Expand All @@ -424,7 +511,7 @@ macro_rules! spi_dma {
type ReceivedWord = u8;
}

impl<REMAP, PINS> Spi<$SPIi, REMAP, PINS> {
impl<REMAP, PINS> Spi<$SPIi, REMAP, PINS, u8> {
pub fn with_tx_dma(self, channel: $TCi) -> SpiTxDma<$SPIi, REMAP, PINS, $TCi> {
let payload = SpiPayload { spi: self };
SpiTxDma { payload, channel }
Expand Down