esp32-hal-cpu.c

// 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 "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"
#include "freertos/task.h"
#include "esp_attr.h"
#include "esp_log.h"
#include "soc/rtc.h"
#include "soc/rtc_cntl_reg.h"
#include "rom/rtc.h"
#include "esp32-hal.h"
#include "esp32-hal-cpu.h"

typedef struct apb_change_cb_s {
        struct apb_change_cb_s * next;
        void * arg;
        apb_change_cb_t cb;
} apb_change_t;

static apb_change_t * apb_change_callbacks = NULL;
static xSemaphoreHandle apb_change_lock = NULL;

static uint32_t _cpu_freq_mhz = CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ;
static uint32_t _sys_time_multiplier = 1;

uint64_t IRAM_ATTR micros64(){
    return (uint64_t)(esp_timer_get_time()) * _sys_time_multiplier;
}

//ToDo: figure out how to set FreeRTOS tick properly
void delay(uint32_t ms){
    vTaskDelay((ms * _cpu_freq_mhz) / (portTICK_PERIOD_MS * CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ));
}

static uint32_t calculateApb(rtc_cpu_freq_config_t * conf){
    if(conf->freq_mhz >= 80){
        return 80000000;
    }
    return (conf->source_freq_mhz * 1000000) / conf->div;
}

static void initApbChangeCallback(){
    static volatile bool initialized = false;
    if(!initialized){
        initialized = true;
        apb_change_lock = xSemaphoreCreateMutex();
        if(!apb_change_lock){
            initialized = false;
        }
    }
}

static void triggerApbChangeCallback(apb_change_ev_t ev_type, uint32_t old_apb, uint32_t new_apb){
    initApbChangeCallback();
    xSemaphoreTake(apb_change_lock, portMAX_DELAY);
    apb_change_t * r = apb_change_callbacks;
    while(r != NULL){
        r->cb(r->arg, ev_type, old_apb, new_apb);
    }
    xSemaphoreGive(apb_change_lock);
}

bool addApbChangeCallback(void * arg, apb_change_cb_t cb){
    initApbChangeCallback();
    apb_change_t * c = (apb_change_t*)malloc(sizeof(apb_change_t));
    if(!c){
        log_e("Callback Object Malloc Failed");
        return false;
    }
    c->next = NULL;
    c->arg = arg;
    c->cb = cb;
    xSemaphoreTake(apb_change_lock, portMAX_DELAY);
    if(apb_change_callbacks == NULL){
        apb_change_callbacks = c;
    } else {
        apb_change_t * r = apb_change_callbacks;
        if(r->cb != cb || r->arg != arg){
            while(r->next){
                r = r->next;
                if(r->cb == cb && r->arg == arg){
                    goto unlock_and_exit;
                }
            }
            r->next = c;
        }
    }
unlock_and_exit:
    xSemaphoreGive(apb_change_lock);
    return true;
}

bool removeApbChangeCallback(void * arg, apb_change_cb_t cb){
    initApbChangeCallback();
    xSemaphoreTake(apb_change_lock, portMAX_DELAY);
    apb_change_t * r = apb_change_callbacks;
    if(r == NULL){
        xSemaphoreGive(apb_change_lock);
        return false;
    }
    if(r->cb == cb && r->arg == arg){
        apb_change_callbacks = r->next;
        free(r);
    } else {
        while(r->next && (r->next->cb != cb || r->next->arg != arg)){
            r = r->next;
        }
        if(r->next == NULL || r->next->cb != cb || r->next->arg != arg){
            xSemaphoreGive(apb_change_lock);
            return false;
        }
        apb_change_t * c = r->next;
        r->next = c->next;
        free(c);
    }
    xSemaphoreGive(apb_change_lock);
    return true;
}

bool setCpuFrequency(uint32_t cpu_freq_mhz){
    rtc_cpu_freq_config_t conf, cconf;
    uint32_t capb, apb;
    rtc_clk_cpu_freq_get_config(&cconf);
    if(cconf.freq_mhz == cpu_freq_mhz && _cpu_freq_mhz == cpu_freq_mhz){
        return true;
    }
    if(!rtc_clk_cpu_freq_mhz_to_config(cpu_freq_mhz, &conf)){
        log_e("CPU clock could not be set to %u MHz", cpu_freq_mhz);
        return false;
    }
    capb = calculateApb(&cconf);
    apb = calculateApb(&conf);
    log_i("%s: %u / %u = %u Mhz", (conf.source == RTC_CPU_FREQ_SRC_PLL)?"PLL":((conf.source == RTC_CPU_FREQ_SRC_APLL)?"APLL":((conf.source == RTC_CPU_FREQ_SRC_XTAL)?"XTAL":"8M")), conf.source_freq_mhz, conf.div, conf.freq_mhz);
    if(capb != apb && apb_change_callbacks){
        triggerApbChangeCallback(APB_BEFORE_CHANGE, capb, apb);
    }
    rtc_clk_cpu_freq_set_config_fast(&conf);
    _cpu_freq_mhz = conf.freq_mhz;
    _sys_time_multiplier = 80000000 / apb;
    if(capb != apb && apb_change_callbacks){
        triggerApbChangeCallback(APB_AFTER_CHANGE, capb, apb);
    }
    return true;
}

uint32_t getCpuFrequency(){
    rtc_cpu_freq_config_t conf;
    rtc_clk_cpu_freq_get_config(&conf);
    return conf.freq_mhz;
}

uint32_t getApbFrequency(){
    rtc_cpu_freq_config_t conf;
    rtc_clk_cpu_freq_get_config(&conf);
    return calculateApb(&conf);
}