MCXA: Add a function to read Reset Reason

3 files changed, 124 insertions, 0 deletions

diff --git a/embassy-mcxa/src/lib.rs b/embassy-mcxa/src/lib.rs
index be279e509..7de5839be 100644
--- a/embassy-mcxa/src/lib.rs
+++ b/embassy-mcxa/src/lib.rs
@@ -17,6 +17,7 @@ pub mod i2c;
 pub mod interrupt;
 pub mod lpuart;
 pub mod ostimer;
+pub mod reset_reason;
 pub mod rtc;
 
 pub use crate::pac::NVIC_PRIO_BITS;
diff --git a/embassy-mcxa/src/reset_reason.rs b/embassy-mcxa/src/reset_reason.rs
new file mode 100644
index 000000000..1f5a0ec1f
--- /dev/null
+++ b/embassy-mcxa/src/reset_reason.rs
@@ -0,0 +1,108 @@
+//! Reset reason
+//!
+//! MCXA families keep the most recent reset reason in the SRS
+//! register of the CMC block. This lets users understand why the MCU
+//! has reset and take appropriate corrective actions if required.
+
+/// Reads the most recent reset reason from the Core Mode Controller
+/// (CMC).
+pub fn reset_reason() -> ResetReason {
+    critical_section::with(|_| {
+        let regs = unsafe { &*crate::pac::Cmc::steal() };
+
+        let srs = regs.srs().read();
+
+        if srs.wakeup().is_enabled() {
+            ResetReason::WakeUp
+        } else if srs.por().bit_is_set() {
+            ResetReason::Por
+        } else if srs.vd().bit_is_set() {
+            ResetReason::VoltageDetect
+        } else if srs.warm().bit_is_set() {
+            ResetReason::Warm
+        } else if srs.fatal().bit_is_set() {
+            ResetReason::Fatal
+        } else if srs.pin().bit_is_set() {
+            ResetReason::Pin
+        } else if srs.dap().bit_is_set() {
+            ResetReason::Dap
+        } else if srs.rstack().bit_is_set() {
+            ResetReason::ResetAckTimeout
+        } else if srs.lpack().bit_is_set() {
+            ResetReason::LowPowerAckTimeout
+        } else if srs.scg().bit_is_set() {
+            ResetReason::SystemClockGeneration
+        } else if srs.wwdt0().bit_is_set() {
+            ResetReason::Wwdt0
+        } else if srs.sw().bit_is_set() {
+            ResetReason::Software
+        } else if srs.lockup().bit_is_set() {
+            ResetReason::Lockup
+        } else if srs.cdog0().bit_is_set() {
+            ResetReason::Cdog0
+        } else if srs.cdog1().bit_is_set() {
+            ResetReason::Cdog1
+        } else if srs.jtag().bit_is_set() {
+            ResetReason::Jtag
+        } else {
+            ResetReason::Tamper
+        }
+    })
+}
+
+/// Indicates the type and source of the most recent reset.
+#[derive(Clone, Copy, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub enum ResetReason {
+    /// Tamper reset.
+    Tamper,
+
+    /// JTAG System Reset request.
+    Jtag,
+
+    /// Code Watchdog 0 reset.
+    Cdog0,
+
+    /// Code Watchdog 1 reset.
+    Cdog1,
+
+    /// Lockup reset.
+    Lockup,
+
+    /// Software reset.
+    Software,
+
+    /// Windowed Watchdog 0 reset.
+    Wwdt0,
+
+    /// System clock generation reset.
+    SystemClockGeneration,
+
+    /// Low Power Acknowledge Timeout reset.
+    LowPowerAckTimeout,
+
+    /// Reset Timeout.
+    ResetAckTimeout,
+
+    /// Debug Access Port reset.
+    Dap,
+
+    /// External assertion of RESET_b pin.
+    Pin,
+
+    /// Fatal reset.
+    Fatal,
+
+    /// Warm reset.
+    Warm,
+
+    /// Voltage detect reset.
+    VoltageDetect,
+
+    /// Power-on reset.
+    Por,
+
+    /// Wake-up reset.
+    WakeUp,
+}
diff --git a/examples/mcxa/src/bin/reset-reason.rs b/examples/mcxa/src/bin/reset-reason.rs
new file mode 100644
index 000000000..c244fbe04
--- /dev/null
+++ b/examples/mcxa/src/bin/reset-reason.rs
@@ -0,0 +1,15 @@
+#![no_std]
+#![no_main]
+
+use embassy_executor::Spawner;
+use hal::config::Config;
+use hal::reset_reason::reset_reason;
+use {defmt_rtt as _, embassy_mcxa as hal, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let config = Config::default();
+    let _p = hal::init(config);
+
+    defmt::info!("Reset Reason: '{}'", reset_reason());
+}