/* * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #include #include #include #include #include "sdkconfig.h" #include "esp_attr.h" #include "esp_log.h" #include "esp_private/esp_clk.h" #include "esp_clk_internal.h" #include "esp32c2/rom/ets_sys.h" #include "esp32c2/rom/uart.h" #include "esp32c2/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 "hal/cpu_hal.h" #include "hal/wdt_hal.h" #include "esp_private/periph_ctrl.h" #include "bootloader_clock.h" #include "soc/syscon_reg.h" #include "esp_rom_uart.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_ESP32C2_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 150 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"; __attribute__((weak)) void esp_clk_init(void) { #if !CONFIG_IDF_ENV_FPGA rtc_config_t cfg = RTC_CONFIG_DEFAULT(); soc_reset_reason_t rst_reas; rst_reas = esp_rom_get_reset_reason(0); if (rst_reas == RESET_REASON_CHIP_POWER_ON) { cfg.cali_ocode = 1; } rtc_init(cfg); assert(rtc_clk_xtal_freq_get() == RTC_XTAL_FREQ_40M); rtc_clk_fast_freq_set(RTC_FAST_FREQ_8M); #endif #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 150kHz to 32kHz, then the timeout set for the WDT will increase 4.6 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 150kHz to 32kHz then WDT timeout will increased to 1.6sec * 150/32 = 7.5 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_ESP32C2_RTC_CLK_SRC_EXT_OSC) select_rtc_slow_clk(SLOW_CLK_32K_EXT_OSC); #elif defined(CONFIG_ESP32C2_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() / 1000); 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_ESP32C2_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 esp_rom_uart_tx_wait_idle(CONFIG_ESP_CONSOLE_UART_NUM); if (res) { rtc_clk_cpu_freq_set_config(&new_config); } // Re calculate the ccount to make time calculation correct. cpu_hal_set_cycle_count( (uint64_t)cpu_hal_get_cycle_count() * new_freq_mhz / old_freq_mhz ); } 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 */ int retry_32k_xtal = 3; 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"); // 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 150 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. */ __attribute__((weak)) 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; soc_reset_reason_t rst_reason = esp_rom_get_reset_reason(0); /* For reason that only reset CPU, do not disable the clocks * that have been enabled before reset. */ if (rst_reason == RESET_REASON_CPU0_MWDT0 || rst_reason == RESET_REASON_CPU0_SW || rst_reason == RESET_REASON_CPU0_RTC_WDT || rst_reason == RESET_REASON_CPU0_JTAG) { common_perip_clk = ~READ_PERI_REG(SYSTEM_PERIP_CLK_EN0_REG); hwcrypto_perip_clk = ~READ_PERI_REG(SYSTEM_PERIP_CLK_EN1_REG); wifi_bt_sdio_clk = ~READ_PERI_REG(SYSTEM_WIFI_CLK_EN_REG); } else { common_perip_clk = SYSTEM_SPI2_CLK_EN | #if CONFIG_ESP_CONSOLE_UART_NUM != 0 SYSTEM_UART_CLK_EN | #endif #if CONFIG_ESP_CONSOLE_UART_NUM != 1 SYSTEM_UART1_CLK_EN | #endif SYSTEM_LEDC_CLK_EN | SYSTEM_I2C_EXT0_CLK_EN | SYSTEM_LEDC_CLK_EN; common_perip_clk1 = 0; hwcrypto_perip_clk = SYSTEM_CRYPTO_SHA_CLK_EN; wifi_bt_sdio_clk = SYSTEM_WIFI_CLK_WIFI_EN | SYSTEM_WIFI_CLK_BT_EN_M | SYSTEM_WIFI_CLK_UNUSED_BIT5 | SYSTEM_WIFI_CLK_UNUSED_BIT12; } //Reset the communication peripherals like I2C, SPI, UART and bring them to known state. common_perip_clk |= SYSTEM_SPI2_CLK_EN | #if CONFIG_ESP_CONSOLE_UART_NUM != 0 SYSTEM_UART_CLK_EN | #endif #if CONFIG_ESP_CONSOLE_UART_NUM != 1 SYSTEM_UART1_CLK_EN | #endif SYSTEM_I2C_EXT0_CLK_EN; common_perip_clk1 = 0; /* Disable some peripheral clocks. */ CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, common_perip_clk); SET_PERI_REG_MASK(SYSTEM_PERIP_RST_EN0_REG, common_perip_clk); CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN1_REG, common_perip_clk1); SET_PERI_REG_MASK(SYSTEM_PERIP_RST_EN1_REG, common_perip_clk1); /* Disable hardware crypto clocks. */ CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN1_REG, hwcrypto_perip_clk); SET_PERI_REG_MASK(SYSTEM_PERIP_RST_EN1_REG, hwcrypto_perip_clk); /* Disable WiFi/BT/SDIO clocks. */ CLEAR_PERI_REG_MASK(SYSTEM_WIFI_CLK_EN_REG, wifi_bt_sdio_clk); SET_PERI_REG_MASK(SYSTEM_WIFI_CLK_EN_REG, SYSTEM_WIFI_CLK_EN); /* Set WiFi light sleep clock source to RTC slow clock */ REG_SET_FIELD(SYSTEM_BT_LPCK_DIV_INT_REG, SYSTEM_BT_LPCK_DIV_NUM, 0); CLEAR_PERI_REG_MASK(SYSTEM_BT_LPCK_DIV_FRAC_REG, SYSTEM_LPCLK_SEL_8M); SET_PERI_REG_MASK(SYSTEM_BT_LPCK_DIV_FRAC_REG, SYSTEM_LPCLK_SEL_RTC_SLOW); /* Enable RNG clock. */ periph_module_enable(PERIPH_RNG_MODULE); }