STM: Add usart v2

2 files changed, 143 insertions, 13 deletions

diff --git a/embassy-stm32/src/bdma/v1.rs b/embassy-stm32/src/bdma/v1.rs
index 584d531f7..13caf329b 100644
--- a/embassy-stm32/src/bdma/v1.rs
+++ b/embassy-stm32/src/bdma/v1.rs
@@ -35,13 +35,15 @@ impl State {
 static STATE: State = State::new();
 
 #[allow(unused)]
-pub(crate) async unsafe fn transfer_p2m(ch: &mut impl Channel, src: *const u8, dst: &mut [u8]) {
+pub(crate) async unsafe fn transfer_p2m(
+    regs: pac::bdma::Ch,
+    state_number: usize,
+    src: *const u8,
+    dst: &mut [u8],
+) {
     // ndtr is max 16 bits.
     assert!(dst.len() <= 0xFFFF);
 
-    let regs: pac::bdma::Ch = ch.regs();
-    let state_number = ch.state_num();
-
     // Reset status
     // Generate a DMB here to flush the store buffer (M7) before enabling the DMA
     STATE.ch_status[state_number].store(CH_STATUS_NONE, Ordering::Release);
@@ -82,13 +84,15 @@ pub(crate) async unsafe fn transfer_p2m(ch: &mut impl Channel, src: *const u8, d
 }
 
 #[allow(unused)]
-pub(crate) async unsafe fn transfer_m2p(ch: &mut impl Channel, src: &[u8], dst: *mut u8) {
+pub(crate) async unsafe fn transfer_m2p(
+    regs: pac::bdma::Ch,
+    state_number: usize,
+    src: &[u8],
+    dst: *mut u8,
+) {
     // ndtr is max 16 bits.
     assert!(src.len() <= 0xFFFF);
 
-    let regs: pac::bdma::Ch = ch.regs();
-    let state_number = ch.state_num();
-
     // Reset status
     // Generate a DMB here to flush the store buffer (M7) before enabling the DMA
     STATE.ch_status[state_number].store(CH_STATUS_NONE, Ordering::Release);
@@ -168,7 +172,7 @@ pub(crate) mod sealed {
     }
 
     pub trait Channel {
-        fn dma_regs() -> &'static pac::bdma::Dma;
+        fn dma_regs() -> pac::bdma::Dma;
 
         fn state_num(&self) -> usize;
 
@@ -199,8 +203,8 @@ macro_rules! impl_dma_channel {
         impl Channel for crate::peripherals::$channel_peri {}
         impl sealed::Channel for crate::peripherals::$channel_peri {
             #[inline]
-            fn dma_regs() -> &'static pac::bdma::Dma {
-                &crate::pac::$dma_peri
+            fn dma_regs() -> pac::bdma::Dma {
+                crate::pac::$dma_peri
             }
 
             fn state_num(&self) -> usize {
@@ -222,7 +226,11 @@ macro_rules! impl_dma_channel {
             where
                 T: 'a,
             {
-                unsafe { transfer_m2p(self, buf, dst) }
+                use sealed::Channel as _Channel;
+
+                let state_num = self.state_num();
+                let regs = self.regs();
+                unsafe { transfer_m2p(regs, state_num, buf, dst) }
             }
         }
 
@@ -240,7 +248,11 @@ macro_rules! impl_dma_channel {
             where
                 T: 'a,
             {
-                unsafe { transfer_p2m(self, src, buf) }
+                use sealed::Channel as _Channel;
+
+                let state_num = self.state_num();
+                let regs = self.regs();
+                unsafe { transfer_p2m(regs, state_num, src, buf) }
             }
         }
     };
diff --git a/embassy-stm32/src/usart/v2.rs b/embassy-stm32/src/usart/v2.rs
index 8b1378917..271eff850 100644
--- a/embassy-stm32/src/usart/v2.rs
+++ b/embassy-stm32/src/usart/v2.rs
@@ -1 +1,119 @@
+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);
+
+        // Uncomment once we find all of the H7's UART clocks.
+        T::enable();
+        let pclk_freq = T::frequency();
+
+        // TODO: better calculation, including error checking and OVER8 if possible.
+        let div = pclk_freq.0 / 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_m0(vals::M0::BIT8);
+                w.set_m1(vals::M1::M0);
+                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.tdr().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.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(|w| w.set_dr(b as u16));
+            }
+        }
+        Ok(())
+    }
+    fn bflush(&mut self) -> Result<(), Self::Error> {
+        unsafe {
+            let r = self.inner.regs();
+            while !r.isr().read().tc() {}
+        }
+        Ok(())
+    }
+}