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esp-idf/components/esp32s2/clk.c

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// Copyright 2015-2017 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 <sys/cdefs.h>
#include <sys/time.h>
#include <sys/param.h>
#include "sdkconfig.h"
#include "esp_attr.h"
#include "esp_log.h"
#include "esp32s2/clk.h"
#include "esp_clk_internal.h"
#include "esp32s2/rom/ets_sys.h"
#include "esp32s2/rom/uart.h"
#include "esp32s2/rom/rtc.h"
#include "soc/system_reg.h"
#include "soc/dport_access.h"
#include "soc/soc.h"
#include "soc/rtc.h"
#include "soc/rtc_periph.h"
#include "soc/i2s_reg.h"
#include "hal/wdt_hal.h"
#include "driver/periph_ctrl.h"
#include "xtensa/core-macros.h"
#include "bootloader_clock.h"
#include "soc/syscon_reg.h"
/* Number of cycles to wait from the 32k XTAL oscillator to consider it running.
* Larger values increase startup delay. Smaller values may cause false positive
* detection (i.e. oscillator runs for a few cycles and then stops).
*/
#define SLOW_CLK_CAL_CYCLES CONFIG_ESP32S2_RTC_CLK_CAL_CYCLES
#define MHZ (1000000)
/* Lower threshold for a reasonably-looking calibration value for a 32k XTAL.
* The ideal value (assuming 32768 Hz frequency) is 1000000/32768*(2**19) = 16*10^6.
*/
#define MIN_32K_XTAL_CAL_VAL 15000000L
/* Indicates that this 32k oscillator gets input from external oscillator, rather
* than a crystal.
*/
#define EXT_OSC_FLAG BIT(3)
/* This is almost the same as rtc_slow_freq_t, except that we define
* an extra enum member for the external 32k oscillator.
* For convenience, lower 2 bits should correspond to rtc_slow_freq_t values.
*/
typedef enum {
SLOW_CLK_RTC = RTC_SLOW_FREQ_RTC, //!< Internal 90 kHz RC oscillator
SLOW_CLK_32K_XTAL = RTC_SLOW_FREQ_32K_XTAL, //!< External 32 kHz XTAL
SLOW_CLK_8MD256 = RTC_SLOW_FREQ_8MD256, //!< Internal 8 MHz RC oscillator, divided by 256
SLOW_CLK_32K_EXT_OSC = RTC_SLOW_FREQ_32K_XTAL | EXT_OSC_FLAG //!< External 32k oscillator connected to 32K_XP pin
} slow_clk_sel_t;
static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
static const char *TAG = "clk";
void esp_clk_init(void)
{
rtc_config_t cfg = RTC_CONFIG_DEFAULT();
rtc_init(cfg);
assert(rtc_clk_xtal_freq_get() == RTC_XTAL_FREQ_40M);
rtc_clk_fast_freq_set(RTC_FAST_FREQ_8M);
#ifdef CONFIG_BOOTLOADER_WDT_ENABLE
// WDT uses a SLOW_CLK clock source. After a function select_rtc_slow_clk a frequency of this source can changed.
// If the frequency changes from 90kHz to 32kHz, then the timeout set for the WDT will increase 2.8 times.
// Therefore, for the time of frequency change, set a new lower timeout value (1.6 sec).
// This prevents excessive delay before resetting in case the supply voltage is drawdown.
// (If frequency is changed from 90kHz to 32kHz then WDT timeout will increased to 1.6sec * 90/32 = 4.5 sec).
wdt_hal_context_t rtc_wdt_ctx = {.inst = WDT_RWDT, .rwdt_dev = &RTCCNTL};
uint32_t stage_timeout_ticks = (uint32_t)(1600ULL * rtc_clk_slow_freq_get_hz() / 1000ULL);
wdt_hal_write_protect_disable(&rtc_wdt_ctx);
wdt_hal_feed(&rtc_wdt_ctx);
//Bootloader has enabled RTC WDT until now. We're only modifying timeout, so keep the stage and timeout action the same
wdt_hal_config_stage(&rtc_wdt_ctx, WDT_STAGE0, stage_timeout_ticks, WDT_STAGE_ACTION_RESET_RTC);
wdt_hal_write_protect_enable(&rtc_wdt_ctx);
#endif
#if defined(CONFIG_ESP32S2_RTC_CLK_SRC_EXT_CRYS)
select_rtc_slow_clk(SLOW_CLK_32K_XTAL);
#elif defined(CONFIG_ESP32S2_RTC_CLK_SRC_EXT_OSC)
select_rtc_slow_clk(SLOW_CLK_32K_EXT_OSC);
#elif defined(CONFIG_ESP32S2_RTC_CLK_SRC_INT_8MD256)
select_rtc_slow_clk(SLOW_CLK_8MD256);
#else
select_rtc_slow_clk(RTC_SLOW_FREQ_RTC);
#endif
#ifdef CONFIG_BOOTLOADER_WDT_ENABLE
// After changing a frequency WDT timeout needs to be set for new frequency.
stage_timeout_ticks = (uint32_t)((uint64_t)CONFIG_BOOTLOADER_WDT_TIME_MS * rtc_clk_slow_freq_get_hz() / 1000ULL);
wdt_hal_write_protect_disable(&rtc_wdt_ctx);
wdt_hal_feed(&rtc_wdt_ctx);
wdt_hal_config_stage(&rtc_wdt_ctx, WDT_STAGE0, stage_timeout_ticks, WDT_STAGE_ACTION_RESET_RTC);
wdt_hal_write_protect_enable(&rtc_wdt_ctx);
#endif
rtc_cpu_freq_config_t old_config, new_config;
rtc_clk_cpu_freq_get_config(&old_config);
const uint32_t old_freq_mhz = old_config.freq_mhz;
const uint32_t new_freq_mhz = CONFIG_ESP32S2_DEFAULT_CPU_FREQ_MHZ;
bool res = rtc_clk_cpu_freq_mhz_to_config(new_freq_mhz, &new_config);
assert(res);
// Wait for UART TX to finish, otherwise some UART output will be lost
// when switching APB frequency
uart_tx_wait_idle(CONFIG_ESP_CONSOLE_UART_NUM);
rtc_clk_cpu_freq_set_config(&new_config);
// Re calculate the ccount to make time calculation correct.
XTHAL_SET_CCOUNT( (uint64_t)XTHAL_GET_CCOUNT() * new_freq_mhz / old_freq_mhz );
}
int IRAM_ATTR esp_clk_cpu_freq(void)
{
return ets_get_cpu_frequency() * 1000000;
}
int IRAM_ATTR esp_clk_apb_freq(void)
{
return MIN(ets_get_cpu_frequency(), 80) * 1000000;
}
static void select_rtc_slow_clk(slow_clk_sel_t slow_clk)
{
rtc_slow_freq_t rtc_slow_freq = slow_clk & RTC_CNTL_ANA_CLK_RTC_SEL_V;
uint32_t cal_val = 0;
/* number of times to repeat 32k XTAL calibration
* before giving up and switching to the internal RC
*/
#ifdef CONFIG_IDF_TARGET_ESP32
int retry_32k_xtal = 1; /* don't change the behavior for the ESP32 */
#else
int retry_32k_xtal = 3;
#endif
do {
if (rtc_slow_freq == RTC_SLOW_FREQ_32K_XTAL) {
/* 32k XTAL oscillator needs to be enabled and running before it can
* be used. Hardware doesn't have a direct way of checking if the
* oscillator is running. Here we use rtc_clk_cal function to count
* the number of main XTAL cycles in the given number of 32k XTAL
* oscillator cycles. If the 32k XTAL has not started up, calibration
* will time out, returning 0.
*/
ESP_EARLY_LOGD(TAG, "waiting for 32k oscillator to start up");
if (slow_clk == SLOW_CLK_32K_XTAL) {
rtc_clk_32k_enable(true);
} else if (slow_clk == SLOW_CLK_32K_EXT_OSC) {
rtc_clk_32k_enable_external();
}
// When SLOW_CLK_CAL_CYCLES is set to 0, clock calibration will not be performed at startup.
if (SLOW_CLK_CAL_CYCLES > 0) {
cal_val = rtc_clk_cal(RTC_CAL_32K_XTAL, SLOW_CLK_CAL_CYCLES);
if (cal_val == 0 || cal_val < MIN_32K_XTAL_CAL_VAL) {
if (retry_32k_xtal-- > 0) {
continue;
}
ESP_EARLY_LOGW(TAG, "32 kHz XTAL not found, switching to internal 90 kHz oscillator");
rtc_slow_freq = RTC_SLOW_FREQ_RTC;
}
}
} else if (rtc_slow_freq == RTC_SLOW_FREQ_8MD256) {
rtc_clk_8m_enable(true, true);
}
rtc_clk_slow_freq_set(rtc_slow_freq);
if (SLOW_CLK_CAL_CYCLES > 0) {
/* TODO: 32k XTAL oscillator has some frequency drift at startup.
* Improve calibration routine to wait until the frequency is stable.
*/
cal_val = rtc_clk_cal(RTC_CAL_RTC_MUX, SLOW_CLK_CAL_CYCLES);
} else {
const uint64_t cal_dividend = (1ULL << RTC_CLK_CAL_FRACT) * 1000000ULL;
cal_val = (uint32_t) (cal_dividend / rtc_clk_slow_freq_get_hz());
}
} while (cal_val == 0);
ESP_EARLY_LOGD(TAG, "RTC_SLOW_CLK calibration value: %d", cal_val);
esp_clk_slowclk_cal_set(cal_val);
}
void rtc_clk_select_rtc_slow_clk(void)
{
select_rtc_slow_clk(RTC_SLOW_FREQ_32K_XTAL);
}
/* This function is not exposed as an API at this point.
* All peripheral clocks are default enabled after chip is powered on.
* This function disables some peripheral clocks when cpu starts.
* These peripheral clocks are enabled when the peripherals are initialized
* and disabled when they are de-initialized.
*/
void esp_perip_clk_init(void)
{
uint32_t common_perip_clk, hwcrypto_perip_clk, wifi_bt_sdio_clk = 0;
uint32_t common_perip_clk1 = 0;
RESET_REASON rst_reas[1];
rst_reas[0] = rtc_get_reset_reason(0);
/* For reason that only reset CPU, do not disable the clocks
* that have been enabled before reset.
*/
if (rst_reas[0] >= TG0WDT_CPU_RESET &&
rst_reas[0] <= TG0WDT_CPU_RESET &&
rst_reas[0] != RTCWDT_BROWN_OUT_RESET) {
common_perip_clk = ~DPORT_READ_PERI_REG(DPORT_PERIP_CLK_EN_REG);
hwcrypto_perip_clk = ~DPORT_READ_PERI_REG(DPORT_PERIP_CLK_EN1_REG);
wifi_bt_sdio_clk = ~DPORT_READ_PERI_REG(DPORT_WIFI_CLK_EN_REG);
} else {
common_perip_clk = DPORT_WDG_CLK_EN |
DPORT_I2S0_CLK_EN |
#if CONFIG_ESP_CONSOLE_UART_NUM != 0
DPORT_UART_CLK_EN |
#endif
#if CONFIG_ESP_CONSOLE_UART_NUM != 1
DPORT_UART1_CLK_EN |
#endif
DPORT_USB_CLK_EN |
DPORT_SPI2_CLK_EN |
DPORT_I2C_EXT0_CLK_EN |
DPORT_UHCI0_CLK_EN |
DPORT_RMT_CLK_EN |
DPORT_PCNT_CLK_EN |
DPORT_LEDC_CLK_EN |
DPORT_TIMERGROUP1_CLK_EN |
DPORT_SPI3_CLK_EN |
DPORT_SPI4_CLK_EN |
DPORT_PWM0_CLK_EN |
DPORT_CAN_CLK_EN |
DPORT_PWM1_CLK_EN |
DPORT_I2S1_CLK_EN |
DPORT_SPI2_DMA_CLK_EN |
DPORT_SPI3_DMA_CLK_EN |
DPORT_PWM2_CLK_EN |
DPORT_PWM3_CLK_EN;
common_perip_clk1 = 0;
hwcrypto_perip_clk = DPORT_CRYPTO_AES_CLK_EN |
DPORT_CRYPTO_SHA_CLK_EN |
DPORT_CRYPTO_RSA_CLK_EN;
wifi_bt_sdio_clk = DPORT_WIFI_CLK_WIFI_EN |
DPORT_WIFI_CLK_BT_EN_M |
DPORT_WIFI_CLK_UNUSED_BIT5 |
DPORT_WIFI_CLK_UNUSED_BIT12 |
DPORT_WIFI_CLK_SDIOSLAVE_EN |
DPORT_WIFI_CLK_SDIO_HOST_EN |
DPORT_WIFI_CLK_EMAC_EN;
}
//Reset the communication peripherals like I2C, SPI, UART, I2S and bring them to known state.
common_perip_clk |= DPORT_I2S0_CLK_EN |
#if CONFIG_ESP_CONSOLE_UART_NUM != 0
DPORT_UART_CLK_EN |
#endif
#if CONFIG_ESP_CONSOLE_UART_NUM != 1
DPORT_UART1_CLK_EN |
#endif
DPORT_USB_CLK_EN |
DPORT_SPI2_CLK_EN |
DPORT_I2C_EXT0_CLK_EN |
DPORT_UHCI0_CLK_EN |
DPORT_RMT_CLK_EN |
DPORT_UHCI1_CLK_EN |
DPORT_SPI3_CLK_EN |
DPORT_SPI4_CLK_EN |
DPORT_I2C_EXT1_CLK_EN |
DPORT_I2S1_CLK_EN |
DPORT_SPI2_DMA_CLK_EN |
DPORT_SPI3_DMA_CLK_EN;
common_perip_clk1 = 0;
/* Change I2S clock to audio PLL first. Because if I2S uses 160MHz clock,
* the current is not reduced when disable I2S clock.
*/
REG_SET_FIELD(I2S_CLKM_CONF_REG(0), I2S_CLK_SEL, I2S_CLK_AUDIO_PLL);
REG_SET_FIELD(I2S_CLKM_CONF_REG(1), I2S_CLK_SEL, I2S_CLK_AUDIO_PLL);
/* Disable some peripheral clocks. */
DPORT_CLEAR_PERI_REG_MASK(DPORT_PERIP_CLK_EN_REG, common_perip_clk);
DPORT_SET_PERI_REG_MASK(DPORT_PERIP_RST_EN_REG, common_perip_clk);
DPORT_CLEAR_PERI_REG_MASK(DPORT_PERIP_CLK_EN1_REG, common_perip_clk1);
DPORT_SET_PERI_REG_MASK(DPORT_PERIP_RST_EN1_REG, common_perip_clk1);
/* Disable hardware crypto clocks. */
DPORT_CLEAR_PERI_REG_MASK(DPORT_PERIP_CLK_EN1_REG, hwcrypto_perip_clk);
DPORT_SET_PERI_REG_MASK(DPORT_PERIP_RST_EN1_REG, hwcrypto_perip_clk);
/* Disable WiFi/BT/SDIO clocks. */
DPORT_CLEAR_PERI_REG_MASK(DPORT_WIFI_CLK_EN_REG, wifi_bt_sdio_clk);
/* Enable WiFi MAC and POWER clocks */
DPORT_SET_PERI_REG_MASK(DPORT_WIFI_CLK_EN_REG, DPORT_WIFI_CLK_WIFI_EN);
/* Enable RNG clock. */
periph_module_enable(PERIPH_RNG_MODULE);
}
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