From b34de84450f25645d2f6ebf6a946d73d6b8d9fb2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?D=C3=A1niel=20Buga?= <bugadani@gmail.com>
Date: Thu, 16 Jan 2025 13:30:21 +0100
Subject: [PATCH] Mark Async drivers !Send

---
 esp-hal/CHANGELOG.md                        |  2 ++
 esp-hal/MIGRATING-0.23.md                   | 23 ++++++++++++++++++++-
 esp-hal/src/lib.rs                          |  6 +++++-
 hil-test/tests/embassy_interrupt_spi_dma.rs | 20 +++++++-----------
 4 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/esp-hal/CHANGELOG.md b/esp-hal/CHANGELOG.md
index b8ac2e40692..d108a1a57d4 100644
--- a/esp-hal/CHANGELOG.md
+++ b/esp-hal/CHANGELOG.md
@@ -22,6 +22,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `Rng` and `Trng` now implement `Peripheral<P = Self>` (#2992)
 
+- `Async` drivers are no longer `Send` (#2980)
+
 ### Fixed
 
 - `DmaDescriptor` is now `#[repr(C)]` (#2988)
diff --git a/esp-hal/MIGRATING-0.23.md b/esp-hal/MIGRATING-0.23.md
index c57ff7193a7..665092650b4 100644
--- a/esp-hal/MIGRATING-0.23.md
+++ b/esp-hal/MIGRATING-0.23.md
@@ -1,4 +1,25 @@
-# Migration Guide from v0.23.x to v?.??.?
+# Migration Guide from v0.23.x to v1.0.0-beta.0
+
+## `Async` drivers can no longer be sent between cores and executors
+
+To work around this limitation, send the blocking driver, and configure it into `Async` mode
+in the target context.
+
+```diff
+ #[embassy_executor::task]
+-async fn interrupt_driven_task(mut spi: Spi<'static, Async>) {
++async fn interrupt_driven_task(spi: Spi<'static, Blocking>) {
++    let mut spi = spi.into_async();
+     ...
+ }
+
+ let spi = Spi::new(...)
+     .unwrap()
+     // ...
+-    .into_async();
+
+ send_spawner.spawn(interrupt_driven_task(spi)).unwrap();
+```
 
 ## RMT changes
 
diff --git a/esp-hal/src/lib.rs b/esp-hal/src/lib.rs
index 89640e0bba3..f6a44e3bce5 100644
--- a/esp-hal/src/lib.rs
+++ b/esp-hal/src/lib.rs
@@ -143,6 +143,8 @@
 // MUST be the first module
 mod fmt;
 
+use core::marker::PhantomData;
+
 #[cfg(riscv)]
 #[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
 #[cfg_attr(not(feature = "unstable"), doc(hidden))]
@@ -321,7 +323,9 @@ pub struct Blocking;
 
 /// Driver initialized in async mode.
 #[derive(Debug)]
-pub struct Async;
+pub struct Async(PhantomData<*const ()>);
+
+unsafe impl Sync for Async {}
 
 impl crate::DriverMode for Blocking {}
 impl crate::DriverMode for Async {}
diff --git a/hil-test/tests/embassy_interrupt_spi_dma.rs b/hil-test/tests/embassy_interrupt_spi_dma.rs
index e6505fe94bc..a751fe5581f 100644
--- a/hil-test/tests/embassy_interrupt_spi_dma.rs
+++ b/hil-test/tests/embassy_interrupt_spi_dma.rs
@@ -18,7 +18,7 @@ use esp_hal::{
     },
     time::RateExtU32,
     timer::AnyTimer,
-    Async,
+    Blocking,
 };
 use esp_hal_embassy::InterruptExecutor;
 use hil_test as _;
@@ -37,14 +37,14 @@ static INTERRUPT_TASK_WORKING: AtomicBool = AtomicBool::new(false);
 
 #[cfg(any(esp32, esp32s2, esp32s3))]
 #[embassy_executor::task]
-async fn interrupt_driven_task(spi: esp_hal::spi::master::SpiDma<'static, Async>) {
+async fn interrupt_driven_task(spi: esp_hal::spi::master::SpiDma<'static, Blocking>) {
     let mut ticker = Ticker::every(Duration::from_millis(1));
 
     let (rx_buffer, rx_descriptors, tx_buffer, tx_descriptors) = dma_buffers!(128);
     let dma_rx_buf = DmaRxBuf::new(rx_descriptors, rx_buffer).unwrap();
     let dma_tx_buf = DmaTxBuf::new(tx_descriptors, tx_buffer).unwrap();
 
-    let mut spi = spi.with_buffers(dma_rx_buf, dma_tx_buf);
+    let mut spi = spi.with_buffers(dma_rx_buf, dma_tx_buf).into_async();
 
     loop {
         let mut buffer: [u8; 8] = [0; 8];
@@ -59,9 +59,11 @@ async fn interrupt_driven_task(spi: esp_hal::spi::master::SpiDma<'static, Async>
 
 #[cfg(not(any(esp32, esp32s2, esp32s3)))]
 #[embassy_executor::task]
-async fn interrupt_driven_task(mut i2s_tx: esp_hal::i2s::master::I2sTx<'static, Async>) {
+async fn interrupt_driven_task(i2s_tx: esp_hal::i2s::master::I2s<'static, Blocking>) {
     let mut ticker = Ticker::every(Duration::from_millis(1));
 
+    let mut i2s_tx = i2s_tx.into_async().i2s_tx.build();
+
     loop {
         let mut buffer: [u8; 8] = [0; 8];
 
@@ -137,14 +139,13 @@ mod test {
                 .with_mode(Mode::_0),
         )
         .unwrap()
-        .with_dma(dma_channel2)
-        .into_async();
+        .with_dma(dma_channel2);
 
         #[cfg(not(any(esp32, esp32s2, esp32s3)))]
         let other_peripheral = {
             let (_, rx_descriptors, _, tx_descriptors) = dma_buffers!(128);
 
-            let other_peripheral = esp_hal::i2s::master::I2s::new(
+            esp_hal::i2s::master::I2s::new(
                 peripherals.I2S0,
                 esp_hal::i2s::master::Standard::Philips,
                 esp_hal::i2s::master::DataFormat::Data8Channel8,
@@ -153,11 +154,6 @@ mod test {
                 rx_descriptors,
                 tx_descriptors,
             )
-            .into_async()
-            .i2s_tx
-            .build();
-
-            other_peripheral
         };
 
         let sw_ints = SoftwareInterruptControl::new(peripherals.SW_INTERRUPT);