Fix implementations of embedded_io::Write for UartPeripheral (#895)

Fixes #840
rp-rs · Feb 4, 2025 · eea9ecf · eea9ecf
1 parent d927dce
commit eea9ecf
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Showing 4 changed files with 8 additions and 4 deletions.
diff --git a/rp2040-hal/src/uart/peripheral.rs b/rp2040-hal/src/uart/peripheral.rs
@@ -504,8 +504,9 @@ impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::ReadReady
 
 impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::Write for UartPeripheral<Enabled, D, P> {
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
-        self.write_full_blocking(buf);
-        Ok(buf.len())
+        // Blocks if and only if no bytes can be written.
+        let remaining = nb::block!(super::writer::write_raw(&self.device, buf)).unwrap(); // Infallible
+        Ok(buf.len() - remaining.len())
     }
     fn flush(&mut self) -> Result<(), Self::Error> {
         nb::block!(super::writer::transmit_flushed(&self.device)).unwrap(); // Infallible

diff --git a/rp2040-hal/src/uart/writer.rs b/rp2040-hal/src/uart/writer.rs
@@ -214,6 +214,7 @@ impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::ErrorType for Writer<D,
 
 impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::Write for Writer<D, P> {
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
+        // Blocks if and only if no bytes can be written.
         let remaining = nb::block!(write_raw(&self.device, buf)).unwrap(); // Infallible
         Ok(buf.len() - remaining.len())
     }

diff --git a/rp235x-hal/src/uart/peripheral.rs b/rp235x-hal/src/uart/peripheral.rs
@@ -504,8 +504,9 @@ impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::ReadReady
 
 impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::Write for UartPeripheral<Enabled, D, P> {
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
-        self.write_full_blocking(buf);
-        Ok(buf.len())
+        // Blocks if and only if no bytes can be written.
+        let remaining = nb::block!(super::writer::write_raw(&self.device, buf)).unwrap(); // Infallible
+        Ok(buf.len() - remaining.len())
     }
     fn flush(&mut self) -> Result<(), Self::Error> {
         nb::block!(super::writer::transmit_flushed(&self.device)).unwrap(); // Infallible

diff --git a/rp235x-hal/src/uart/writer.rs b/rp235x-hal/src/uart/writer.rs
@@ -215,6 +215,7 @@ impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::ErrorType for Writer<D,
 
 impl<D: UartDevice, P: ValidUartPinout<D>> embedded_io::Write for Writer<D, P> {
     fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
+        // Blocks if and only if no bytes can be written.
         let remaining = nb::block!(write_raw(&self.device, buf)).unwrap(); // Infallible
         Ok(buf.len() - remaining.len())
     }