Use bare_metal::CriticalSection for GPIO configuration

Author: urdh

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Updated the `cast` dependency from 0.2 to 0.3
+- Use `bare_metal::CriticalSection` for GPIO configuration (breaking change)
 
 ### Added
 

examples/adc_values.rs

@@ -7,7 +7,8 @@ use stm32f0xx_hal as hal;
 
 use crate::hal::{pac, prelude::*};
 
-use cortex_m::{interrupt::Mutex, peripheral::syst::SystClkSource::Core};
+use bare_metal::Mutex;
+use cortex_m::peripheral::syst::SystClkSource::Core;
 use cortex_m_rt::{entry, exception};
 
 use core::{cell::RefCell, fmt::Write};
@@ -25,7 +26,12 @@ fn main() -> ! {
         hal::pac::Peripherals::take(),
         cortex_m::peripheral::Peripherals::take(),
     ) {
-        cortex_m::interrupt::free(move |cs| {
+        cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+
             let mut flash = p.FLASH;
             let mut rcc = p.RCC.configure().sysclk(8.mhz()).freeze(&mut flash);
 
@@ -60,7 +66,7 @@ fn main() -> ! {
             tx.write_str("\n\rThis ADC example will read various values using the ADC and print them out to the serial terminal\r\n").ok();
 
             // Move all components under Mutex supervision
-            *SHARED.borrow(cs).borrow_mut() = Some(Shared { adc, tx });
+            *SHARED.borrow(*cs).borrow_mut() = Some(Shared { adc, tx });
         });
     }
 
@@ -74,7 +80,12 @@ fn SysTick() {
     use core::ops::DerefMut;
 
     // Enter critical section
-    cortex_m::interrupt::free(|cs| {
+    cortex_m::interrupt::free(|_| {
+        // SAFETY: We are in a critical section, but the `cortex_m` critical section
+        // token is not compatible with the `bare_metal` token. Future version of the
+        // `cortex_m` crate will not supply *any* token to this callback!
+        let cs = unsafe { bare_metal::CriticalSection::new() };
+
         // Get access to the Mutex protected shared data
         if let Some(ref mut shared) = SHARED.borrow(cs).borrow_mut().deref_mut() {
             // Read temperature data from internal sensor using ADC

examples/blinky.rs

@@ -17,7 +17,13 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // (Re-)configure PA1 as output
-        let mut led = cortex_m::interrupt::free(|cs| gpioa.pa1.into_push_pull_output(cs));
+        let mut led = cortex_m::interrupt::free(|_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+            gpioa.pa1.into_push_pull_output(cs)
+        });
 
         loop {
             // Turn PA1 on a million times in a row

examples/blinky_adc.rs

@@ -17,7 +17,12 @@ fn main() -> ! {
 
         let gpioa = p.GPIOA.split(&mut rcc);
 
-        let (mut led, mut an_in) = cortex_m::interrupt::free(move |cs| {
+        let (mut led, mut an_in) = cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+
             (
                 // (Re-)configure PA1 as output
                 gpioa.pa1.into_push_pull_output(cs),

examples/blinky_delay.rs

@@ -18,7 +18,13 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // (Re-)configure PA1 as output
-        let mut led = cortex_m::interrupt::free(move |cs| gpioa.pa1.into_push_pull_output(cs));
+        let mut led = cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+            gpioa.pa1.into_push_pull_output(cs)
+        });
 
         // Get delay provider
         let mut delay = Delay::new(cp.SYST, &rcc);

examples/blinky_multiple.rs

@@ -18,7 +18,12 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
         let gpiob = p.GPIOB.split(&mut rcc);
 
-        let (led1, led2) = cortex_m::interrupt::free(move |cs| {
+        let (led1, led2) = cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+
             (
                 // (Re-)configure PA1 as output
                 gpioa.pa1.into_push_pull_output(cs),

examples/blinky_timer.rs

@@ -17,7 +17,13 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // (Re-)configure PA1 as output
-        let mut led = cortex_m::interrupt::free(move |cs| gpioa.pa1.into_push_pull_output(cs));
+        let mut led = cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+            gpioa.pa1.into_push_pull_output(cs)
+        });
 
         // Set up a timer expiring after 1s
         let mut timer = Timer::tim1(p.TIM1, Hertz(1), &mut rcc);

examples/blinky_timer_irq.rs

@@ -15,8 +15,9 @@ use crate::hal::{
 
 use cortex_m_rt::entry;
 
+use bare_metal::Mutex;
 use core::cell::RefCell;
-use cortex_m::{interrupt::Mutex, peripheral::Peripherals as c_m_Peripherals};
+use cortex_m::peripheral::Peripherals as c_m_Peripherals;
 
 // A type definition for the GPIO pin to be used for our LED
 type LEDPIN = gpioa::PA5<Output<PushPull>>;
@@ -35,14 +36,24 @@ fn TIM7() {
     static mut INT: Option<Timer<TIM7>> = None;
 
     let led = LED.get_or_insert_with(|| {
-        cortex_m::interrupt::free(|cs| {
+        cortex_m::interrupt::free(|_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { bare_metal::CriticalSection::new() };
+
             // Move LED pin here, leaving a None in its place
             GLED.borrow(cs).replace(None).unwrap()
         })
     });
 
     let int = INT.get_or_insert_with(|| {
-        cortex_m::interrupt::free(|cs| {
+        cortex_m::interrupt::free(|_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { bare_metal::CriticalSection::new() };
+
             // Move LED pin here, leaving a None in its place
             GINT.borrow(cs).replace(None).unwrap()
         })
@@ -55,7 +66,12 @@ fn TIM7() {
 #[entry]
 fn main() -> ! {
     if let (Some(mut p), Some(cp)) = (Peripherals::take(), c_m_Peripherals::take()) {
-        cortex_m::interrupt::free(move |cs| {
+        cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+
             let mut rcc = p
                 .RCC
                 .configure()
@@ -71,7 +87,7 @@ fn main() -> ! {
             let led = gpioa.pa5.into_push_pull_output(cs);
 
             // Move the pin into our global storage
-            *GLED.borrow(cs).borrow_mut() = Some(led);
+            *GLED.borrow(*cs).borrow_mut() = Some(led);
 
             // Set up a timer expiring after 1s
             let mut timer = Timer::tim7(p.TIM7, Hertz(1), &mut rcc);
@@ -80,7 +96,7 @@ fn main() -> ! {
             timer.listen(Event::TimeOut);
 
             // Move the timer into our global storage
-            *GINT.borrow(cs).borrow_mut() = Some(timer);
+            *GINT.borrow(*cs).borrow_mut() = Some(timer);
 
             // Enable TIM7 IRQ, set prio 1 and clear any pending IRQs
             let mut nvic = cp.NVIC;

examples/dac.rs

@@ -24,7 +24,13 @@ fn main() -> ! {
         let mut rcc = dp.RCC.configure().sysclk(8.mhz()).freeze(&mut dp.FLASH);
         let gpioa = dp.GPIOA.split(&mut rcc);
 
-        let pa4 = cortex_m::interrupt::free(move |cs| gpioa.pa4.into_analog(cs));
+        let pa4 = cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+            gpioa.pa4.into_analog(cs)
+        });
 
         let mut dac = dac(dp.DAC, pa4, &mut rcc);
 

examples/flash_systick.rs

@@ -7,7 +7,8 @@ use stm32f0xx_hal as hal;
 
 use crate::hal::{gpio::*, pac, prelude::*};
 
-use cortex_m::{interrupt::Mutex, peripheral::syst::SystClkSource::Core, Peripherals};
+use bare_metal::Mutex;
+use cortex_m::{peripheral::syst::SystClkSource::Core, Peripherals};
 use cortex_m_rt::{entry, exception};
 
 use core::cell::RefCell;
@@ -19,7 +20,12 @@ static GPIO: Mutex<RefCell<Option<gpioa::PA1<Output<PushPull>>>>> = Mutex::new(R
 #[entry]
 fn main() -> ! {
     if let (Some(mut p), Some(cp)) = (pac::Peripherals::take(), Peripherals::take()) {
-        cortex_m::interrupt::free(move |cs| {
+        cortex_m::interrupt::free(move |_| {
+            // SAFETY: We are in a critical section, but the `cortex_m` critical section
+            // token is not compatible with the `bare_metal` token. Future version of the
+            // `cortex_m` crate will not supply *any* token to this callback!
+            let cs = unsafe { &bare_metal::CriticalSection::new() };
+
             let mut rcc = p.RCC.configure().sysclk(48.mhz()).freeze(&mut p.FLASH);
 
             let gpioa = p.GPIOA.split(&mut rcc);
@@ -28,7 +34,7 @@ fn main() -> ! {
             let led = gpioa.pa1.into_push_pull_output(cs);
 
             // Transfer GPIO into a shared structure
-            *GPIO.borrow(cs).borrow_mut() = Some(led);
+            *GPIO.borrow(*cs).borrow_mut() = Some(led);
 
             let mut syst = cp.SYST;
 
@@ -62,7 +68,12 @@ fn SysTick() {
     static mut STATE: u8 = 1;
 
     // Enter critical section
-    cortex_m::interrupt::free(|cs| {
+    cortex_m::interrupt::free(|_| {
+        // SAFETY: We are in a critical section, but the `cortex_m` critical section
+        // token is not compatible with the `bare_metal` token. Future version of the
+        // `cortex_m` crate will not supply *any* token to this callback!
+        let cs = unsafe { bare_metal::CriticalSection::new() };
+
         // Borrow access to our GPIO pin from the shared structure
         if let Some(ref mut led) = *GPIO.borrow(cs).borrow_mut().deref_mut() {
             // Check state variable, keep LED off most of the time and turn it on every 10th tick