esp-idf/components/esp32/crosscore_int.c

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// Copyright 2015-2016 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.
#include <stdint.h>
#include <string.h>
#include "esp_attr.h"
#include "esp_err.h"
#include "esp_intr.h"
#include "esp_intr_alloc.h"
#include "rom/ets_sys.h"
#include "rom/uart.h"
#include "soc/cpu.h"
#include "soc/dport_reg.h"
#include "soc/io_mux_reg.h"
#include "soc/rtc_cntl_reg.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/queue.h"
#include "freertos/portmacro.h"
#define REASON_YIELD (1<<0)
static portMUX_TYPE reasonSpinlock = portMUX_INITIALIZER_UNLOCKED;
static volatile uint32_t reason[ portNUM_PROCESSORS ];
/*
ToDo: There is a small chance the CPU already has yielded when this ISR is serviced. In that case, it's running the intended task but
the ISR will cause it to switch _away_ from it. portYIELD_FROM_ISR will probably just schedule the task again, but have to check that.
*/
static void IRAM_ATTR esp_crosscore_isr(void *arg) {
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uint32_t myReasonVal;
//A pointer to the correct reason array item is passed to this ISR.
volatile uint32_t *myReason=arg;
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//Clear the interrupt first.
if (xPortGetCoreID()==0) {
DPORT_WRITE_PERI_REG(DPORT_CPU_INTR_FROM_CPU_0_REG, 0);
} else {
DPORT_WRITE_PERI_REG(DPORT_CPU_INTR_FROM_CPU_1_REG, 0);
}
//Grab the reason and clear it.
portENTER_CRITICAL(&reasonSpinlock);
myReasonVal=*myReason;
*myReason=0;
portEXIT_CRITICAL(&reasonSpinlock);
//Check what we need to do.
if (myReasonVal&REASON_YIELD) {
portYIELD_FROM_ISR();
}
}
//Initialize the crosscore interrupt on this core. Call this once
//on each active core.
void esp_crosscore_int_init() {
portENTER_CRITICAL(&reasonSpinlock);
reason[xPortGetCoreID()]=0;
portEXIT_CRITICAL(&reasonSpinlock);
esp_err_t err;
if (xPortGetCoreID()==0) {
err = esp_intr_alloc(ETS_FROM_CPU_INTR0_SOURCE, ESP_INTR_FLAG_IRAM, esp_crosscore_isr, (void*)&reason[xPortGetCoreID()], NULL);
} else {
err = esp_intr_alloc(ETS_FROM_CPU_INTR1_SOURCE, ESP_INTR_FLAG_IRAM, esp_crosscore_isr, (void*)&reason[xPortGetCoreID()], NULL);
}
assert(err == ESP_OK);
}
void IRAM_ATTR esp_crosscore_int_send_yield(int coreId) {
assert(coreId<portNUM_PROCESSORS);
//Mark the reason we interrupt the other CPU
portENTER_CRITICAL(&reasonSpinlock);
reason[coreId]|=REASON_YIELD;
portEXIT_CRITICAL(&reasonSpinlock);
//Poke the other CPU.
if (coreId==0) {
DPORT_WRITE_PERI_REG(DPORT_CPU_INTR_FROM_CPU_0_REG, DPORT_CPU_INTR_FROM_CPU_0);
} else {
DPORT_WRITE_PERI_REG(DPORT_CPU_INTR_FROM_CPU_1_REG, DPORT_CPU_INTR_FROM_CPU_1);
}
}