esp-idf/components/esp32/cpu_freq.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 "rom/ets_sys.h"
#include "rom/uart.h"
#include "sdkconfig.h"
#include "phy.h"
#include "rtc.h"
#include "soc/soc.h"
#include "soc/rtc_cntl_reg.h"
/*
* This function is not exposed as an API at this point,
* because FreeRTOS doesn't yet support dynamic changing of
* CPU frequency. Also we need to implement hooks for
* components which want to be notified of CPU frequency
* changes.
*/
void esp_set_cpu_freq(void)
{
uint32_t freq_mhz = CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ;
phy_get_romfunc_addr();
// freq will be changed to 40MHz in rtc_init_lite,
// wait uart tx finish, otherwise some uart output will be lost
uart_tx_wait_idle(CONFIG_CONSOLE_UART_NUM);
rtc_init_lite(XTAL_AUTO);
// work around a bug that RTC fast memory may be isolated
// from the system after rtc_init_lite
SET_PERI_REG_MASK(RTC_CNTL_PWC_REG, RTC_CNTL_FASTMEM_FORCE_NOISO_M);
cpu_freq_t freq = CPU_80M;
switch(freq_mhz) {
case 240:
freq = CPU_240M;
break;
case 160:
freq = CPU_160M;
break;
default:
freq_mhz = 80;
/* no break */
case 80:
freq = CPU_80M;
break;
}
// freq will be changed to freq in rtc_set_cpu_freq,
// wait uart tx finish, otherwise some uart output will be lost
uart_tx_wait_idle(CONFIG_CONSOLE_UART_NUM);
rtc_set_cpu_freq(freq);
ets_update_cpu_frequency(freq_mhz);
}