OVMS3-idf/components/esp_common/include/esp_expression_with_stack.h

// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef __ESP_EXPRESSION_WITH_STACK_H
#define __ESP_EXPRESSION_WITH_STACK_H

#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
#include "esp_debug_helpers.h"


/**
 * @brief Executes a 1-line expression with a application alocated stack
 * @param lock Mutex object to protect in case of shared stack
 * @param stack Pointer to user alocated stack
 * @param stack_size Size of current stack in bytes
 * @param expression Expression or function to be executed using the stack
 */
#define ESP_EXECUTE_EXPRESSION_WITH_STACK(lock, stack, stack_size, expression)  \
({                                                                  \
    if (lock && stack && stack_size) {                              \
        uint32_t backup;                                            \
        xSemaphoreTake(lock, portMAX_DELAY);                        \
        StackType_t *top_of_stack = esp_switch_stack_setup(stack, stack_size);\
        esp_switch_stack_enter(top_of_stack, &backup);              \
        {                                                           \
            expression;                                             \
        }                                                           \
        esp_switch_stack_exit(&backup);                             \
        xSemaphoreGive(lock);                                       \
    }                                                               \
})

/**
 * @brief Fill stack frame with CPU-specifics value before use
 * @param stack Caller allocated stack pointer
 * @param stack_size Size of stack in bytes
 * @return New pointer to the top of stack
 * @note Application must not call this function directly
 */
StackType_t * esp_switch_stack_setup(StackType_t *stack, size_t stack_size);

/**
 * @brief Changes CPU sp-register to use another stack space and save the previous one
 * @param stack Caller allocated stack pointer
 * @param backup_stack Pointer to a place to save the current stack
 * @note Application must not call this function directly
 */
extern void esp_switch_stack_enter(StackType_t *stack, uint32_t *backup_stack);

/**
 * @brief Restores the previous CPU sp-register
 * @param backup_stack Pointer to the place where stack was saved
 * @note Application must not call this function directly
 */
extern void esp_switch_stack_exit(uint32_t *backup_stack);

#endif