RIOT/cpu/esp32/freertos/task.c

/*
 * Copyright (C) 2018 Gunar Schorcht
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 *
 * FreeRTOS to RIOT-OS adaption module for source code compatibility
 */

#ifndef DOXYGEN

#define ENABLE_DEBUG (0)
#include "debug.h"

#include <string.h>

#include "esp_common.h"
#include "esp_attr.h"
#include "log.h"
#include "syscalls.h"
#include "thread.h"
#include "xtimer.h"

#include "soc/soc.h"

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#define MHZ 1000000

/**
 * @brief   Architecture specific data of thread control blocks
 */
typedef struct {
    uint32_t saved_int_state;
    uint32_t critical_nesting;
} thread_arch_ext_t;

volatile thread_arch_ext_t threads_arch_exts[KERNEL_PID_LAST + 1] = {};

BaseType_t xTaskCreatePinnedToCore (TaskFunction_t pvTaskCode,
                                    const char * const pcName,
                                    const uint32_t usStackDepth,
                                    void * const pvParameters,
                                    UBaseType_t uxPriority,
                                    TaskHandle_t * const pvCreatedTask,
                                    const BaseType_t xCoreID)
{
    /* FreeRTOS priority values have to be inverted */
    uxPriority = SCHED_PRIO_LEVELS - uxPriority - 1;

    DEBUG("%s name=%s size=%d prio=%d pvCreatedTask=%p ",
          __func__, pcName, usStackDepth, uxPriority, pvCreatedTask);

    char* stack = malloc(usStackDepth + sizeof(thread_t));

    if (!stack) {
        return pdFALSE;
    }
    kernel_pid_t pid = thread_create(stack,
                                     usStackDepth + sizeof(thread_t),
                                     uxPriority,
                                     THREAD_CREATE_WOUT_YIELD |
                                     THREAD_CREATE_STACKTEST,
                                     (thread_task_func_t)pvTaskCode,
                                     pvParameters, pcName);
    DEBUG("pid=%d\n", pid);

    if (pvCreatedTask) {
        *pvCreatedTask = (TaskHandle_t)(0L + pid);
    }

    return (pid < 0) ? pdFALSE : pdTRUE;
}

BaseType_t xTaskCreate (TaskFunction_t pvTaskCode,
                        const char * const pcName,
                        const uint32_t usStackDepth,
                        void * const pvParameters,
                        UBaseType_t uxPriority,
                        TaskHandle_t * const pvCreatedTask)
{
    return xTaskCreatePinnedToCore (pvTaskCode,
                                    pcName,
                                    usStackDepth,
                                    pvParameters,
                                    uxPriority,
                                    pvCreatedTask,
                                    PRO_CPU_NUM);
}

void vTaskDelete (TaskHandle_t xTaskToDelete)
{
    DEBUG("%s pid=%d task=%p\n", __func__, thread_getpid(), xTaskToDelete);

    CHECK_PARAM(xTaskToDelete != NULL);

    uint32_t pid = (uint32_t)xTaskToDelete;

    /* remove old task from scheduling */
    thread_t* thread = (thread_t*)sched_threads[pid];
    sched_set_status(thread, STATUS_STOPPED);
    sched_threads[pid] = NULL;
    sched_num_threads--;
    sched_active_thread = NULL;

    /* determine the new running task */
    sched_run();
}

TaskHandle_t xTaskGetCurrentTaskHandle(void)
{
    DEBUG("%s pid=%d\n", __func__, thread_getpid());

    uint32_t pid = thread_getpid();
    return (TaskHandle_t)pid;
}

void vTaskDelay( const TickType_t xTicksToDelay )
{
    uint64_t us = xTicksToDelay * MHZ / xPortGetTickRateHz();
    xtimer_usleep(us);
}

TickType_t xTaskGetTickCount (void)
{
    return system_get_time() / USEC_PER_MSEC / portTICK_PERIOD_MS;
}

void vTaskEnterCritical( portMUX_TYPE *mux )
{
    /* determine calling thread pid (can't fail) */
    kernel_pid_t my_pid = thread_getpid();

    DEBUG("%s pid=%d prio=%d mux=%p\n", __func__,
          my_pid, sched_threads[my_pid]->priority, mux);

    /* disable interrupts */
    uint32_t state = irq_disable();

    /* Locking the given mutex does not work here, 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. */
    /* mutex_lock(mux); */ /* TODO should be only a spin lock */

    /* increment nesting counter and save old interrupt level */
    threads_arch_exts[my_pid].critical_nesting++;
    if (threads_arch_exts[my_pid].critical_nesting == 1) {
        threads_arch_exts[my_pid].saved_int_state = state;
    }
}

void vTaskExitCritical( portMUX_TYPE *mux )
{
    /* determine calling thread pid (can't fail) */
    kernel_pid_t my_pid = thread_getpid();

    DEBUG("%s pid=%d prio=%d mux=%p\n", __func__,
          my_pid, sched_threads[my_pid]->priority, mux);

    /* The given mutex is not used (see vTaskEnterCritical) and has not to
       be unlocked here. */
    /* mutex_unlock(mux); */ /* TODO should be only a spin lock */

    /* decrement nesting counter and restore old interrupt level */
    if (threads_arch_exts[my_pid].critical_nesting) {
        threads_arch_exts[my_pid].critical_nesting--;
        if (threads_arch_exts[my_pid].critical_nesting == 0) {
            irq_restore(threads_arch_exts[my_pid].saved_int_state);
        }
    }
}


#endif /* DOXYGEN */