Merge pull request #8988 from Josar/atmega_isr

cpu/atmega_common: __exit_isr thread_yield

cpu/atmega_common/include/cpu.h

@@ -35,7 +35,8 @@
 
 #include <avr/interrupt.h>
 #include "cpu_conf.h"
-
+#include "sched.h"
+#include "thread.h"
 /**
  * For downwards compatibility with old RIOT code.
  * TODO: remove once core was adjusted
@@ -43,7 +44,8 @@
 #include "irq.h"
 
 #ifdef __cplusplus
-extern "C" {
+extern "C"
+{
 #endif
 
 /**
@@ -52,7 +54,7 @@ extern "C" {
 extern volatile uint8_t __in_isr;
 
 /**
- * @brief Flag entering of an ISR
+ * @brief Run this code on entering interrupt routines
  */
 static inline void __enter_isr(void)
 {
@@ -60,10 +62,22 @@ static inline void __enter_isr(void)
 }
 
 /**
- * @brief Flag exiting of an ISR
+ * @brief   Exit ISR mode and yield with a return from interrupt. Use at the
+ * end of ISRs in place of thread_yield_higher. If thread_yield is needed, use
+ * thread_yield followed by thread_yield_isr instead of thread_yield alone.
+ */
+void thread_yield_isr(void);
+
+/**
+ * @brief Run this code on exiting interrupt routines
  */
 static inline void __exit_isr(void)
 {
+    if (sched_context_switch_request) {
+        thread_yield();
+        __in_isr = 0;
+        thread_yield_isr();
+    }
     __in_isr = 0;
 }
 
@@ -75,7 +89,7 @@ void cpu_init(void);
 /**
  * @brief   Print the last instruction's address
  */
-__attribute__((always_inline)) static inline void cpu_print_last_instruction(void)
+static inline void __attribute__((always_inline)) cpu_print_last_instruction(void)
 {
     uint8_t hi;
     uint8_t lo;
@@ -128,13 +142,6 @@ static inline void atmega_set_prescaler(uint8_t clk_scale)
  */
 void atmega_stdio_init(void);
 
-/**
- * @brief   Exit ISR mode and yield with a return from interrupt. Use at the
- * end of ISRs in place of thread_yield_higher. If thread_yield is needed, use
- * thread_yield followed by thread_yield_isr instead of thread_yield alone.
- */
-void thread_yield_isr(void);
-
 #ifdef __cplusplus
 }
 #endif

cpu/atmega_common/periph/timer.c

@@ -167,11 +167,6 @@ static inline void _isr(tim_t tim, int chan)
     *ctx[tim].mask &= ~(1 << (chan + OCIE1A));
     ctx[tim].cb(ctx[tim].arg, chan);
 
-    if (sched_context_switch_request) {
-        thread_yield();
-        thread_yield_isr();
-    }
-
     __exit_isr();
 }
 #endif

cpu/atmega_common/periph/uart.c

@@ -35,7 +35,6 @@
 
 #include "periph/uart.h"
 
-
 /**
  * @brief   Maximum percentage error in calculated baud before switching to
  *          double speed transmission (U2X)
@@ -90,6 +89,7 @@ static void _update_brr(uart_t uart, uint16_t brr, bool double_speed)
 static void _set_brr(uart_t uart, uint32_t baudrate)
 {
     uint16_t brr;
+
 #if defined(UART_STDIO_BAUDRATE)
     /* UBRR_VALUE and USE_2X are statically computed from <util/setbaud.h> */
     if (baudrate == UART_STDIO_BAUDRATE) {
@@ -134,14 +134,13 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
         dev[uart]->CSRB = (1 << TXEN0);
     }
 
-
     return UART_OK;
 }
 
 void uart_write(uart_t uart, const uint8_t *data, size_t len)
 {
     for (size_t i = 0; i < len; i++) {
-        while (!(dev[uart]->CSRA & (1 << UDRE0))) {};
+        while (!(dev[uart]->CSRA & (1 << UDRE0))) {}
         dev[uart]->DR = data[i];
     }
 }
@@ -160,46 +159,37 @@ void uart_poweroff(uart_t uart)
 
 static inline void isr_handler(int num)
 {
+    __enter_isr();
+
     isr_ctx[num].rx_cb(isr_ctx[num].arg, dev[num]->DR);
 
-    if (sched_context_switch_request) {
+    __exit_isr();
-        thread_yield();
-        thread_yield_isr();
-    }
 }
 
 #ifdef UART_0_ISR
 ISR(UART_0_ISR, ISR_BLOCK)
 {
-    __enter_isr();
     isr_handler(0);
-    __exit_isr();
 }
 #endif /* UART_0_ISR */
 
 #ifdef UART_1_ISR
 ISR(UART_1_ISR, ISR_BLOCK)
 {
-    __enter_isr();
     isr_handler(1);
-    __exit_isr();
 }
 #endif /* UART_1_ISR */
 
 #ifdef UART_2_ISR
 ISR(UART_2_ISR, ISR_BLOCK)
 {
-    __enter_isr();
     isr_handler(2);
-    __exit_isr();
 }
 #endif /* UART_2_ISR */
 
 #ifdef UART_3_ISR
 ISR(UART_3_ISR, ISR_BLOCK)
 {
-    __enter_isr();
     isr_handler(3);
-    __exit_isr();
 }
 #endif /* UART_3_ISR */

cpu/atmega_common/thread_arch.c

@@ -28,7 +28,6 @@
 #include "cpu.h"
 #include "board.h"
 
-
 /*
  * local function declarations  (prefixed with __)
  */
@@ -111,7 +110,6 @@ char *thread_stack_init(thread_task_func_t task_func, void *arg,
     *stk = (uint8_t)0x00;
 #endif
 
-
     /* r0 */
     stk--;
     *stk = (uint8_t)0x00;
@@ -193,8 +191,7 @@ void thread_stack_print(void)
         if ((*sp == 0xFE) && (*(sp + 1) == 0xAF)) {
             found_marker = 0;
         }
-    }
+    } while (found_marker == 1);
-    while (found_marker == 1);
 
     printf("stack size: %u bytes\n", size);
 }
@@ -209,7 +206,6 @@ void cpu_switch_context_exit(void)
 /**
  * @brief Set the MCU into Thread-Mode and load the initial task from the stack and run it
  */
-
 void NORETURN __enter_thread_mode(void) __attribute__((naked));
 void NORETURN __enter_thread_mode(void)
 {
@@ -220,24 +216,25 @@ void NORETURN __enter_thread_mode(void)
     UNREACHABLE();
 }
 
-void thread_yield_higher(void) {
+void thread_yield_higher(void)
+{
     if (irq_is_in() == 0) {
         __context_save();
         sched_run();
         __context_restore();
         __asm__ volatile ("ret");
-    } else {
+    }
+    else {
         sched_context_switch_request = 1;
     }
 }
 
-void thread_yield_isr(void) {
+void thread_yield_isr(void)
+{
     __context_save();
     sched_run();
     __context_restore();
 
-    __exit_isr();
-
     __asm__ volatile ("reti");
 }
 
@@ -293,9 +290,7 @@ __attribute__((always_inline)) static inline void __context_save(void)
         "in   __tmp_reg__, __SP_L__          \n\t"
         "st   x+, __tmp_reg__                \n\t"
         "in   __tmp_reg__, __SP_H__          \n\t"
-        "st   x+, __tmp_reg__                \n\t"
+        "st   x+, __tmp_reg__                \n\t");
-    );
-
 }
 
 __attribute__((always_inline)) static inline void __context_restore(void)
@@ -348,6 +343,5 @@ __attribute__((always_inline)) static inline void __context_restore(void)
 #endif
         "pop  __tmp_reg__                    \n\t"
         "out  __SREG__, __tmp_reg__          \n\t"
-        "pop  __tmp_reg__                    \n\t"
+        "pop  __tmp_reg__                    \n\t");
-    );
 }