117 lines
4.3 KiB
C
117 lines
4.3 KiB
C
// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include "esp_err.h"
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#include "esp_ipc.h"
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#include "esp_attr.h"
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/semphr.h"
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static TaskHandle_t s_ipc_tasks[portNUM_PROCESSORS]; // Two high priority tasks, one for each CPU
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static SemaphoreHandle_t s_ipc_mutex; // This mutex is used as a global lock for esp_ipc_* APIs
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static SemaphoreHandle_t s_ipc_sem[portNUM_PROCESSORS]; // Two semaphores used to wake each of s_ipc_tasks
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static SemaphoreHandle_t s_ipc_ack; // Semaphore used to acknowledge that task was woken up,
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// or function has finished running
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static volatile esp_ipc_func_t s_func; // Function which should be called by high priority task
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static void * volatile s_func_arg; // Argument to pass into s_func
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typedef enum {
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IPC_WAIT_FOR_START,
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IPC_WAIT_FOR_END
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} esp_ipc_wait_t;
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static volatile esp_ipc_wait_t s_ipc_wait; // This variable tells high priority task when it should give
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// s_ipc_ack semaphore: before s_func is called, or
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// after it returns
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static void IRAM_ATTR ipc_task(void* arg)
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{
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const uint32_t cpuid = (uint32_t) arg;
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assert(cpuid == xPortGetCoreID());
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while (true) {
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// Wait for IPC to be initiated.
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// This will be indicated by giving the semaphore corresponding to
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// this CPU.
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if (xSemaphoreTake(s_ipc_sem[cpuid], portMAX_DELAY) != pdTRUE) {
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// TODO: when can this happen?
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abort();
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}
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esp_ipc_func_t func = s_func;
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void* arg = s_func_arg;
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if (s_ipc_wait == IPC_WAIT_FOR_START) {
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xSemaphoreGive(s_ipc_ack);
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}
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(*func)(arg);
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if (s_ipc_wait == IPC_WAIT_FOR_END) {
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xSemaphoreGive(s_ipc_ack);
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}
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}
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// TODO: currently this is unreachable code. Introduce esp_ipc_uninit
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// function which will signal to both tasks that they can shut down.
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// Not critical at this point, we don't have a use case for stopping
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// IPC yet.
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// Also need to delete the semaphore here.
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vTaskDelete(NULL);
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}
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void esp_ipc_init()
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{
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s_ipc_mutex = xSemaphoreCreateMutex();
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s_ipc_ack = xSemaphoreCreateBinary();
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const char* task_names[2] = {"ipc0", "ipc1"};
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for (int i = 0; i < portNUM_PROCESSORS; ++i) {
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s_ipc_sem[i] = xSemaphoreCreateBinary();
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xTaskCreatePinnedToCore(ipc_task, task_names[i], CONFIG_IPC_TASK_STACK_SIZE, (void*) i,
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configMAX_PRIORITIES - 1, &s_ipc_tasks[i], i);
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}
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}
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static esp_err_t esp_ipc_call_and_wait(uint32_t cpu_id, esp_ipc_func_t func, void* arg, esp_ipc_wait_t wait_for)
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{
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if (cpu_id >= portNUM_PROCESSORS) {
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return ESP_ERR_INVALID_ARG;
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}
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if (xTaskGetSchedulerState() != taskSCHEDULER_RUNNING) {
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return ESP_ERR_INVALID_STATE;
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}
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xSemaphoreTake(s_ipc_mutex, portMAX_DELAY);
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s_func = func;
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s_func_arg = arg;
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s_ipc_wait = IPC_WAIT_FOR_START;
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xSemaphoreGive(s_ipc_sem[cpu_id]);
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xSemaphoreTake(s_ipc_ack, portMAX_DELAY);
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xSemaphoreGive(s_ipc_mutex);
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return ESP_OK;
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}
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esp_err_t esp_ipc_call(uint32_t cpu_id, esp_ipc_func_t func, void* arg)
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{
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return esp_ipc_call_and_wait(cpu_id, func, arg, IPC_WAIT_FOR_START);
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}
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esp_err_t esp_ipc_call_blocking(uint32_t cpu_id, esp_ipc_func_t func, void* arg)
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{
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return esp_ipc_call_and_wait(cpu_id, func, arg, IPC_WAIT_FOR_END);
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}
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