Add USARTv3 support.

3 files changed, 174 insertions, 52 deletions

diff --git a/embassy-stm32/src/usart/mod.rs b/embassy-stm32/src/usart/mod.rs
index a75793f8..b957a99c 100644
--- a/embassy-stm32/src/usart/mod.rs
+++ b/embassy-stm32/src/usart/mod.rs
@@ -1,7 +1,8 @@
 #![macro_use]
 
-#[cfg_attr(usart_v1, path = "v1.rs")]
-#[cfg_attr(usart_v2, path = "v2.rs")]
+//#[cfg_attr(usart_v1, path = "v1.rs")]
+//#[cfg_attr(usart_v2, path = "v2.rs")]
+#[cfg_attr(usart_v3, path = "v3.rs")]
 mod _version;
 use crate::peripherals;
 pub use _version::*;
@@ -10,6 +11,51 @@ use crate::gpio::Pin;
 use crate::pac::usart::Usart;
 use crate::rcc::RccPeripheral;
 
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum DataBits {
+    DataBits8,
+    DataBits9,
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum Parity {
+    ParityNone,
+    ParityEven,
+    ParityOdd,
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum StopBits {
+    #[doc = "1 stop bit"]
+    STOP1,
+    #[doc = "0.5 stop bits"]
+    STOP0P5,
+    #[doc = "2 stop bits"]
+    STOP2,
+    #[doc = "1.5 stop bits"]
+    STOP1P5,
+}
+
+#[non_exhaustive]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct Config {
+    pub baudrate: u32,
+    pub data_bits: DataBits,
+    pub stop_bits: StopBits,
+    pub parity: Parity,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            baudrate: 115200,
+            data_bits: DataBits::DataBits8,
+            stop_bits: StopBits::STOP1,
+            parity: Parity::ParityNone,
+        }
+    }
+}
+
 /// Serial error
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
 #[non_exhaustive]
@@ -27,7 +73,7 @@ pub enum Error {
 pub(crate) mod sealed {
     use super::*;
 
-    #[cfg(dma)]
+    #[cfg(any(dma, dmamux))]
     use crate::dma::WriteDma;
 
     pub trait Instance {
@@ -49,10 +95,10 @@ pub(crate) mod sealed {
         fn af_num(&self) -> u8;
     }
 
-    #[cfg(dma)]
+    #[cfg(any(dma, dmamux))]
     pub trait RxDma<T: Instance> {}
 
-    #[cfg(dma)]
+    #[cfg(any(dma, dmamux))]
     pub trait TxDma<T: Instance>: WriteDma<T> {}
 }
 
@@ -63,9 +109,10 @@ pub trait CtsPin<T: Instance>: sealed::CtsPin<T> {}
 pub trait RtsPin<T: Instance>: sealed::RtsPin<T> {}
 pub trait CkPin<T: Instance>: sealed::CkPin<T> {}
 
-#[cfg(dma)]
+#[cfg(any(dma, dmamux))]
 pub trait RxDma<T: Instance>: sealed::RxDma<T> {}
-#[cfg(dma)]
+
+#[cfg(any(dma, dmamux))]
 pub trait TxDma<T: Instance>: sealed::TxDma<T> {}
 
 crate::pac::peripherals!(
diff --git a/embassy-stm32/src/usart/v1.rs b/embassy-stm32/src/usart/v1.rs
index 6c5a1244..16993895 100644
--- a/embassy-stm32/src/usart/v1.rs
+++ b/embassy-stm32/src/usart/v1.rs
@@ -7,51 +7,6 @@ use crate::pac::usart::{regs, vals};
 
 use super::*;
 
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub enum DataBits {
-    DataBits8,
-    DataBits9,
-}
-
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub enum Parity {
-    ParityNone,
-    ParityEven,
-    ParityOdd,
-}
-
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub enum StopBits {
-    #[doc = "1 stop bit"]
-    STOP1,
-    #[doc = "0.5 stop bits"]
-    STOP0P5,
-    #[doc = "2 stop bits"]
-    STOP2,
-    #[doc = "1.5 stop bits"]
-    STOP1P5,
-}
-
-#[non_exhaustive]
-#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-pub struct Config {
-    pub baudrate: u32,
-    pub data_bits: DataBits,
-    pub stop_bits: StopBits,
-    pub parity: Parity,
-}
-
-impl Default for Config {
-    fn default() -> Self {
-        Self {
-            baudrate: 115200,
-            data_bits: DataBits::DataBits8,
-            stop_bits: StopBits::STOP1,
-            parity: Parity::ParityNone,
-        }
-    }
-}
-
 pub struct Uart<'d, T: Instance> {
     inner: T,
     phantom: PhantomData<&'d mut T>,
diff --git a/embassy-stm32/src/usart/v3.rs b/embassy-stm32/src/usart/v3.rs
new file mode 100644
index 00000000..32850c9c
--- /dev/null
+++ b/embassy-stm32/src/usart/v3.rs
@@ -0,0 +1,120 @@
+use core::marker::PhantomData;
+
+use embassy::util::Unborrow;
+use embassy_extras::unborrow;
+
+use crate::pac::usart::{regs, vals};
+
+use super::*;
+
+pub struct Uart<'d, T: Instance> {
+    inner: T,
+    phantom: PhantomData<&'d mut T>,
+}
+
+impl<'d, T: Instance> Uart<'d, T> {
+    pub fn new(
+        inner: impl Unborrow<Target = T>,
+        rx: impl Unborrow<Target = impl RxPin<T>>,
+        tx: impl Unborrow<Target = impl TxPin<T>>,
+        config: Config,
+    ) -> Self {
+        unborrow!(inner, rx, tx);
+
+        T::enable();
+        let pclk_freq = T::frequency();
+
+        // TODO: better calculation, including error checking and OVER8 if possible.
+        let div = (pclk_freq.0 + (config.baudrate / 2)) / config.baudrate;
+
+        let r = inner.regs();
+
+        unsafe {
+            rx.set_as_af(rx.af_num());
+            tx.set_as_af(tx.af_num());
+
+            r.brr().write_value(regs::Brr(div));
+            r.cr1().write(|w| {
+                w.set_ue(true);
+                w.set_te(true);
+                w.set_re(true);
+                w.set_m(0, vals::M0::BIT8);
+                w.set_pce(config.parity != Parity::ParityNone);
+                w.set_ps(match config.parity {
+                    Parity::ParityOdd => vals::Ps::ODD,
+                    Parity::ParityEven => vals::Ps::EVEN,
+                    _ => vals::Ps::EVEN,
+                });
+            });
+            r.cr2().write(|_w| {});
+            r.cr3().write(|_w| {});
+        }
+
+        Self {
+            inner,
+            phantom: PhantomData,
+        }
+    }
+
+    #[cfg(dma)]
+    pub async fn write_dma(&mut self, ch: &mut impl TxDma<T>, buffer: &[u8]) -> Result<(), Error> {
+        unsafe {
+            self.inner.regs().cr3().modify(|reg| {
+                reg.set_dmat(true);
+            });
+        }
+        let r = self.inner.regs();
+        let dst = r.dr().ptr() as *mut u8;
+        ch.transfer(buffer, dst).await;
+        Ok(())
+    }
+
+    pub fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        unsafe {
+            let r = self.inner.regs();
+            for b in buffer {
+                loop {
+                    let sr = r.isr().read();
+                    if sr.pe() {
+                        r.rdr().read();
+                        return Err(Error::Parity);
+                    } else if sr.fe() {
+                        r.rdr().read();
+                        return Err(Error::Framing);
+                    } else if sr.ne() {
+                        r.rdr().read();
+                        return Err(Error::Noise);
+                    } else if sr.ore() {
+                        r.rdr().read();
+                        return Err(Error::Overrun);
+                    } else if sr.rxne() {
+                        break;
+                    }
+                }
+                *b = r.rdr().read().0 as u8;
+            }
+        }
+        Ok(())
+    }
+}
+
+impl<'d, T: Instance> embedded_hal::blocking::serial::Write<u8> for Uart<'d, T> {
+    type Error = Error;
+    fn bwrite_all(&mut self, buffer: &[u8]) -> Result<(), Self::Error> {
+        unsafe {
+            let r = self.inner.regs();
+            for &b in buffer {
+                while !r.isr().read().txe() {}
+                r.tdr().write_value(regs::Tdr(b as u32))
+            }
+        }
+        Ok(())
+    }
+    fn bflush(&mut self) -> Result<(), Self::Error> {
+        unsafe {
+            let r = self.inner.regs();
+            while !r.isr().read().tc() {}
+        }
+        Ok(())
+    }
+}