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cpu/esp32: change of critical section handling in freertos

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Using a mutex for critical section handling with portENTER_CRITICAL and portEXIT_CRITICAL does not work for RIOT, as this function can also be called in the interrupt context. Therefore, the given mutex is not used. Instead, the basic default FreeRTOS mechanism for critical sections is used by simply disabling interrupts. Since context switches for the ESP32 are also based on interrupts, there is no possibility that another thread will enter the critical section once the interrupts are disabled.
This commit is contained in:
Gunar Schorcht 2019-08-01 09:49:24 +02:00 committed by Schorcht
parent 26b71a3f14
commit 1b041083ab
2 changed files with 17 additions and 7 deletions
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17
cpu/esp32/freertos/task.c
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@ -10,7 +10,7 @@
#ifndef DOXYGEN #ifndef DOXYGEN
#define ENABLE_DEBUG 0 #define ENABLE_DEBUG (0)
#include "debug.h" #include "debug.h"
#include <string.h> #include <string.h>
@ -139,8 +139,14 @@ void vTaskEnterCritical( portMUX_TYPE *mux )
/* disable interrupts */ /* disable interrupts */
uint32_t state = irq_disable(); uint32_t state = irq_disable();
/* aquire the mutex with interrupts disabled */ /* Locking the given mutex does not work here, as this function can also
mutex_lock(mux); /* TODO should be only a spin lock */ be called in the interrupt context. Therefore, the given mutex is not
used. Instead, the basic default FreeRTOS mechanism for critical
sections is used by simply disabling interrupts. Since context
switches for the ESP32 are also based on interrupts, there is no
possibility that another thread will enter the critical section
once the interrupts are disabled. */
/* mutex_lock(mux); */ /* TODO should be only a spin lock */
/* increment nesting counter and save old interrupt level */ /* increment nesting counter and save old interrupt level */
threads_arch_exts[my_pid].critical_nesting++; threads_arch_exts[my_pid].critical_nesting++;
@ -157,8 +163,9 @@ void vTaskExitCritical( portMUX_TYPE *mux )
DEBUG("%s pid=%d prio=%d mux=%p\n", __func__, DEBUG("%s pid=%d prio=%d mux=%p\n", __func__,
my_pid, sched_threads[my_pid]->priority, mux); my_pid, sched_threads[my_pid]->priority, mux);
/* release the mutex with interrupts disabled */ /* The given mutex is not used (see vTaskEnterCritical) and has not to
mutex_unlock(mux); /* TODO should be only a spin lock */ be unlocked here. */
/* mutex_unlock(mux); */ /* TODO should be only a spin lock */
/* decrement nesting counter and restore old interrupt level */ /* decrement nesting counter and restore old interrupt level */
if (threads_arch_exts[my_pid].critical_nesting) { if (threads_arch_exts[my_pid].critical_nesting) {

7
cpu/esp32/include/freertos/portmacro.h
View File

@ -30,8 +30,8 @@ extern "C" {
#define portMUX_TYPE mutex_t #define portMUX_TYPE mutex_t
#define portMUX_INITIALIZER_UNLOCKED MUTEX_INIT #define portMUX_INITIALIZER_UNLOCKED MUTEX_INIT
#define portENTER_CRITICAL(pm) mutex_lock(pm) #define portENTER_CRITICAL(mux) vTaskEnterCritical(mux)
#define portEXIT_CRITICAL(pm) mutex_unlock(pm) #define portEXIT_CRITICAL(mux) vTaskExitCritical(mux)
#define portENTER_CRITICAL_NESTED irq_disable #define portENTER_CRITICAL_NESTED irq_disable
#define portEXIT_CRITICAL_NESTED irq_restore #define portEXIT_CRITICAL_NESTED irq_restore
@ -48,6 +48,9 @@ extern "C" {
#define xPortGetCoreID() PRO_CPU_NUM #define xPortGetCoreID() PRO_CPU_NUM
extern void vTaskEnterCritical(portMUX_TYPE *mux);
extern void vTaskExitCritical(portMUX_TYPE *mux);
#ifdef __cplusplus #ifdef __cplusplus
} }
#endif #endif