Fix known SPI issues

esp-hal/CHANGELOG.md

@@ -59,6 +59,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix `SpiBus::transfer` transferring data twice in some cases (#2159)
 - Fixed UART freezing when using `RcFast` clock source on ESP32-C2/C3 (#2170)
 - I2S: on ESP32 and ESP32-S2 data is now output to the right (WS=1) channel first. (#2194)
+- SPI: Fixed an issue where unexpected data was written outside of the read buffer (#2179)
+- SPI: Fixed an issue where `wait` has returned before the DMA has finished writing the memory (#2179)
+- SPI: Fixed an issue where repeated calls to `dma_transfer` may end up looping indefinitely (#2179)
+- SPI: Fixed an issue that prevented correctly reading the first byte in a transaction (#2179)
 
 ### Removed
 

esp-hal/src/dma/mod.rs

@@ -205,6 +205,7 @@ where
 bitfield::bitfield! {
     #[doc(hidden)]
     #[derive(Clone, Copy)]
+    #[cfg_attr(feature = "defmt", derive(defmt::Format))]
     pub struct DmaDescriptorFlags(u32);
 
     u16;
@@ -227,6 +228,7 @@ impl Debug for DmaDescriptorFlags {
 
 /// A DMA transfer descriptor.
 #[derive(Clone, Copy, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct DmaDescriptor {
     pub(crate) flags: DmaDescriptorFlags,
     pub(crate) buffer: *mut u8,
@@ -397,6 +399,29 @@ macro_rules! dma_circular_descriptors {
     };
 }
 
+/// Declares a DMA buffer with a specific size, aligned to 4 bytes
+#[doc(hidden)]
+#[macro_export]
+macro_rules! declare_aligned_dma_buffer {
+    ($name:ident, $size:expr) => {
+        // ESP32 requires word alignment for DMA buffers.
+        // ESP32-S2 technically supports byte-aligned DMA buffers, but the
+        // transfer ends up writing out of bounds.
+        // if the buffer's length is 2 or 3 (mod 4).
+        static mut $name: [u32; ($size + 3) / 4] = [0; ($size + 3) / 4];
+    };
+}
+
+/// Turns the potentially oversized static `u32`` array reference into a
+/// correctly sized `u8` one
+#[doc(hidden)]
+#[macro_export]
+macro_rules! as_mut_byte_array {
+    ($name:ident, $size:expr) => {
+        unsafe { &mut *($name.as_mut_ptr() as *mut [u8; $size]) }
+    };
+}
+
 /// Convenience macro to create DMA buffers and descriptors with specific chunk
 /// size.
 ///
@@ -414,15 +439,15 @@ macro_rules! dma_circular_descriptors {
 #[macro_export]
 macro_rules! dma_buffers_chunk_size {
     ($rx_size:expr, $tx_size:expr, $chunk_size:expr) => {{
-        static mut RX_BUFFER: [u8; $rx_size] = [0u8; $rx_size];
-        static mut TX_BUFFER: [u8; $tx_size] = [0u8; $tx_size];
+        $crate::declare_aligned_dma_buffer!(RX_BUFFER, $rx_size);
+        $crate::declare_aligned_dma_buffer!(TX_BUFFER, $tx_size);
         let (mut rx_descriptors, mut tx_descriptors) =
             $crate::dma_descriptors_chunk_size!($rx_size, $tx_size, $chunk_size);
         unsafe {
             (
-                &mut RX_BUFFER,
+                $crate::as_mut_byte_array!(RX_BUFFER, $rx_size),
                 rx_descriptors,
-                &mut TX_BUFFER,
+                $crate::as_mut_byte_array!(TX_BUFFER, $tx_size),
                 tx_descriptors,
             )
         }
@@ -450,15 +475,15 @@ macro_rules! dma_buffers_chunk_size {
 #[macro_export]
 macro_rules! dma_circular_buffers_chunk_size {
     ($rx_size:expr, $tx_size:expr, $chunk_size:expr) => {{
-        static mut RX_BUFFER: [u8; $rx_size] = [0u8; $rx_size];
-        static mut TX_BUFFER: [u8; $tx_size] = [0u8; $tx_size];
+        $crate::declare_aligned_dma_buffer!(RX_BUFFER, $rx_size);
+        $crate::declare_aligned_dma_buffer!(TX_BUFFER, $tx_size);
         let (mut rx_descriptors, mut tx_descriptors) =
             $crate::dma_circular_descriptors_chunk_size!($rx_size, $tx_size, $chunk_size);
         unsafe {
             (
-                &mut RX_BUFFER,
+                $crate::as_mut_byte_array!(RX_BUFFER, $rx_size),
                 rx_descriptors,
-                &mut TX_BUFFER,
+                $crate::as_mut_byte_array!(TX_BUFFER, $tx_size),
                 tx_descriptors,
             )
         }

esp-hal/src/soc/esp32/gpio.rs

@@ -103,7 +103,7 @@ pub(crate) fn get_io_mux_reg(gpio_num: u8) -> &'static io_mux::GPIO0 {
             37 => transmute::<&'static io_mux::GPIO37, &'static io_mux::GPIO0>(iomux.gpio37()),
             38 => transmute::<&'static io_mux::GPIO38, &'static io_mux::GPIO0>(iomux.gpio38()),
             39 => transmute::<&'static io_mux::GPIO39, &'static io_mux::GPIO0>(iomux.gpio39()),
-            _ => panic!(),
+            other => panic!("GPIO {} does not exist", other),
         }
     }
 }