Use asm::nop in empty loops

See rust-lang/rust#28728

Author: mattico

.github/workflows/clippy.yml

@@ -19,4 +19,4 @@ jobs:
       - uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          args: --examples --target thumbv7em-none-eabihf --features=rt,stm32h743v -- -A clippy::empty_loop
+          args: --examples --target thumbv7em-none-eabihf --features=rt,stm32h743v

examples/dma.rs

@@ -104,5 +104,7 @@ fn main() -> ! {
 
     info!("Memory to Memory DMA completed successfully");
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/fmc.rs

@@ -213,6 +213,8 @@ const APP: () = {
 
         assert_eq!(ram_slice[0], 1);
 
-        loop {}
+        loop {
+            cortex_m::asm::nop()
+        }
     }
 };

examples/fractional-pll.rs

@@ -51,5 +51,7 @@ fn main() -> ! {
 
     let _mco2_ck = ccdr.clocks.mco2_ck().unwrap().0;
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/i2c4_bdma.rs

@@ -129,5 +129,7 @@ fn I2C4_EV() {
 
     assert_eq!(buffer[0], 0xBE);
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/mco.rs

@@ -59,5 +59,7 @@ fn main() -> ! {
 
     info!("MCO outputs running!");
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/prec_kernel_clocks.rs

@@ -49,5 +49,7 @@ fn main() -> ! {
     // Can't change group clocks - ccdr.peripheral has been partially used
     //ccdr.peripheral.kernel_i2c123_clk_mux(I2c123ClkSel::HSI_KER);
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/pwm.rs

@@ -78,5 +78,7 @@ fn main() -> ! {
     pwm.set_duty(max / 2);
     pwm.enable();
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/rcc.rs

@@ -37,5 +37,7 @@ fn main() -> ! {
     info!("sys_ck = {} MHz", ccdr.clocks.sys_ck().0 as f32 / 1e6);
     assert_eq!(ccdr.clocks.sys_ck().0, 100_000_000);
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/sdmmc.rs

@@ -166,5 +166,7 @@ fn main() -> ! {
 
     info!("Done!");
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/spi-dma.rs

@@ -176,5 +176,7 @@ fn main() -> ! {
 
     // We could re-use the stream or spi here
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/vos0.rs

@@ -41,5 +41,7 @@ fn main() -> ! {
     info!("sys_ck = {} MHz", ccdr.clocks.sys_ck().0 as f32 / 1e6);
     assert_eq!(ccdr.clocks.sys_ck().0, 480_000_000);
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }

examples/watchdog.rs

@@ -45,5 +45,7 @@ fn main() -> ! {
     // -> restart the chip
     watchdog.start(100.ms());
 
-    loop {}
+    loop {
+        cortex_m::asm::nop()
+    }
 }