Change DMA write/read to use raw pointers

3 files changed, 39 insertions, 18 deletions

diff --git a/embassy-rp/src/dma.rs b/embassy-rp/src/dma.rs
index 75d7492e0..526c83822 100644
--- a/embassy-rp/src/dma.rs
+++ b/embassy-rp/src/dma.rs
@@ -40,14 +40,14 @@ pub(crate) unsafe fn init() {
 pub unsafe fn read<'a, C: Channel, W: Word>(
     ch: impl Peripheral<P = C> + 'a,
     from: *const W,
-    to: &mut [W],
+    to: *mut W,
+    len: usize,
     dreq: u8,
 ) -> Transfer<'a, C> {
-    let (to_ptr, len) = crate::dma::slice_ptr_parts_mut(to);
     copy_inner(
         ch,
         from as *const u32,
-        to_ptr as *mut u32,
+        to as *mut u32,
         len,
         W::size(),
         false,
@@ -58,14 +58,14 @@ pub unsafe fn read<'a, C: Channel, W: Word>(
 
 pub unsafe fn write<'a, C: Channel, W: Word>(
     ch: impl Peripheral<P = C> + 'a,
-    from: &[W],
+    from: *const W,
     to: *mut W,
+    len: usize,
     dreq: u8,
 ) -> Transfer<'a, C> {
-    let (from_ptr, len) = crate::dma::slice_ptr_parts(from);
     copy_inner(
         ch,
-        from_ptr as *const u32,
+        from as *const u32,
         to as *mut u32,
         len,
         W::size(),
diff --git a/embassy-rp/src/spi.rs b/embassy-rp/src/spi.rs
index 6f68777b2..720aad0e5 100644
--- a/embassy-rp/src/spi.rs
+++ b/embassy-rp/src/spi.rs
@@ -285,6 +285,7 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
     }
 
     pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        let (from_ptr, len) = crate::dma::slice_ptr_parts(buffer);
         let ch = self.tx_dma.as_mut().unwrap();
         let transfer = unsafe {
             self.inner.regs().dmacr().modify(|reg| {
@@ -292,13 +293,14 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
             });
             // If we don't assign future to a variable, the data register pointer
             // is held across an await and makes the future non-Send.
-            crate::dma::write(ch, buffer, self.inner.regs().dr().ptr() as *mut _, T::TX_DREQ)
+            crate::dma::write(ch, from_ptr as *const u32, self.inner.regs().dr().ptr() as *mut _, len, T::TX_DREQ)
         };
         transfer.await;
         Ok(())
     }
 
     pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        let (to_ptr, len) = crate::dma::slice_ptr_parts_mut(buffer);
         let ch = self.rx_dma.as_mut().unwrap();
         let transfer = unsafe {
             self.inner.regs().dmacr().modify(|reg| {
@@ -306,13 +308,24 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
             });
             // If we don't assign future to a variable, the data register pointer
             // is held across an await and makes the future non-Send.
-            crate::dma::read(ch, self.inner.regs().dr().ptr() as *const _, buffer, T::RX_DREQ)
+            crate::dma::read(ch, self.inner.regs().dr().ptr() as *const _, to_ptr as *mut u32, len, T::RX_DREQ)
         };
         transfer.await;
         Ok(())
     }
 
     pub async fn transfer(&mut self, rx_buffer: &mut [u8], tx_buffer: &[u8]) -> Result<(), Error> {
+        self.transfer_inner(rx_buffer, tx_buffer).await
+    }
+
+    pub async fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Error> {
+        self.transfer_inner(words, words).await
+    }
+
+    async fn transfer_inner(&mut self, rx_ptr: *mut [u8], tx_ptr: *const [u8]) -> Result<(), Error> {
+        let (from_ptr, from_len) = crate::dma::slice_ptr_parts(tx_ptr);
+        let (to_ptr, to_len) = crate::dma::slice_ptr_parts_mut(rx_ptr);
+        assert_eq!(from_len, to_len);
         let tx_ch = self.tx_dma.as_mut().unwrap();
         let tx_transfer = unsafe {
             self.inner.regs().dmacr().modify(|reg| {
@@ -320,7 +333,13 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
             });
             // If we don't assign future to a variable, the data register pointer
             // is held across an await and makes the future non-Send.
-            crate::dma::write(tx_ch, tx_buffer, self.inner.regs().dr().ptr() as *mut _, T::TX_DREQ)
+            crate::dma::write(
+                tx_ch,
+                from_ptr as *const u32,
+                self.inner.regs().dr().ptr() as *mut _,
+                from_len,
+                T::TX_DREQ,
+            )
         };
         let rx_ch = self.rx_dma.as_mut().unwrap();
         let rx_transfer = unsafe {
@@ -329,17 +348,17 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
             });
             // If we don't assign future to a variable, the data register pointer
             // is held across an await and makes the future non-Send.
-            crate::dma::read(rx_ch, self.inner.regs().dr().ptr() as *const _, rx_buffer, T::RX_DREQ)
+            crate::dma::read(
+                rx_ch,
+                self.inner.regs().dr().ptr() as *const _,
+                to_ptr as *mut u32,
+                to_len,
+                T::RX_DREQ,
+            )
         };
         join(tx_transfer, rx_transfer).await;
         Ok(())
     }
-
-    pub async fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Error> {
-        let (ptr, len) = crate::dma::slice_ptr_parts(words);
-        let tx_buffer = unsafe { core::slice::from_raw_parts(ptr as *const _, len) };
-        self.transfer(words, tx_buffer).await
-    }
 }
 
 mod sealed {
diff --git a/embassy-rp/src/uart.rs b/embassy-rp/src/uart.rs
index 987b716b4..f8a10bd9d 100644
--- a/embassy-rp/src/uart.rs
+++ b/embassy-rp/src/uart.rs
@@ -120,6 +120,7 @@ impl<'d, T: Instance, M: Mode> UartTx<'d, T, M> {
 
 impl<'d, T: Instance> UartTx<'d, T, Async> {
     pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
+        let (from_ptr, len) = crate::dma::slice_ptr_parts(buffer);
         let ch = self.tx_dma.as_mut().unwrap();
         let transfer = unsafe {
             T::regs().uartdmacr().modify(|reg| {
@@ -127,7 +128,7 @@ impl<'d, T: Instance> UartTx<'d, T, Async> {
             });
             // If we don't assign future to a variable, the data register pointer
             // is held across an await and makes the future non-Send.
-            crate::dma::write(ch, buffer, T::regs().uartdr().ptr() as *mut _, T::TX_DREQ)
+            crate::dma::write(ch, from_ptr as *const u32, T::regs().uartdr().ptr() as *mut _, len, T::TX_DREQ)
         };
         transfer.await;
         Ok(())
@@ -173,6 +174,7 @@ impl<'d, T: Instance, M: Mode> UartRx<'d, T, M> {
 
 impl<'d, T: Instance> UartRx<'d, T, Async> {
     pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
+        let (to_ptr, len) = crate::dma::slice_ptr_parts_mut(buffer);
         let ch = self.rx_dma.as_mut().unwrap();
         let transfer = unsafe {
             T::regs().uartdmacr().modify(|reg| {
@@ -180,7 +182,7 @@ impl<'d, T: Instance> UartRx<'d, T, Async> {
             });
             // If we don't assign future to a variable, the data register pointer
             // is held across an await and makes the future non-Send.
-            crate::dma::read(ch, T::regs().uartdr().ptr() as *const _, buffer, T::RX_DREQ)
+            crate::dma::read(ch, T::regs().uartdr().ptr() as *const _, to_ptr as *mut u32, len, T::RX_DREQ)
         };
         transfer.await;
         Ok(())