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103 lines
4.6 KiB
C
103 lines
4.6 KiB
C
/*
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* SPDX-FileCopyrightText: 2020-2021 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include "sdkconfig.h"
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#include "bootloader_random.h"
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#include "esp_log.h"
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#include "soc/system_reg.h"
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#include "soc/syscon_reg.h"
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#include "soc/apb_saradc_reg.h"
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#include "soc/rtc_cntl_reg.h"
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#include "soc/sens_reg.h"
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#include "hal/regi2c_ctrl.h"
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#include "soc/regi2c_saradc.h"
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void bootloader_random_enable(void)
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{
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SET_PERI_REG_MASK(SYSTEM_WIFI_CLK_EN_REG, SYSTEM_WIFI_CLK_RNG_EN);
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// Enable 8M clock source for RNG (this is actually enough to produce strong random results,
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// but enabling the SAR ADC as well adds some insurance.)
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REG_SET_BIT(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_CLK8M_EN);
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/// Enable SAR ADC to read a disconnected input for additional entropy
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// Reset ADC clock
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SET_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
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CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
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// Enable clock and select clock source for ADC digital controller
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REG_SET_FIELD(APB_SARADC_APB_ADC_CLKM_CONF_REG, APB_SARADC_CLK_SEL, 2); //APB clock
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SET_PERI_REG_MASK(APB_SARADC_CTRL_REG, APB_SARADC_SAR_CLK_GATED);
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SET_PERI_REG_MASK(APB_SARADC_APB_ADC_CLKM_CONF_REG, APB_SARADC_CLK_EN);
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// Read freq = apb_clk / (APB_SARADC_CLKM_DIV_NUM + 1) / TIMER_TARGET / 2
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// Internal ADC sample freq = apb_clk / (APB_SARADC_CLKM_DIV_NUM + 1) / (APB_SARADC_SAR_CLK_DIV + 1)
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// Read frequency has to be at least 35 times lower than the sampling frequency
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REG_SET_FIELD(APB_SARADC_APB_ADC_CLKM_CONF_REG, APB_SARADC_CLKM_DIV_NUM, 3);
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REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_SAR_CLK_DIV, 3); // SAR clock divider has to be at least 2
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REG_SET_FIELD(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_TARGET, 70);
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CLEAR_PERI_REG_MASK(APB_SARADC_CTRL_REG, APB_SARADC_START_FORCE);
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REG_SET_FIELD(SENS_SAR_POWER_XPD_SAR_REG, SENS_FORCE_XPD_SAR, 3);
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CLEAR_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_MEAS_NUM_LIMIT);
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REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_WORK_MODE, 1);
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REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_SAR2_PATT_LEN, 0);
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WRITE_PERI_REG(APB_SARADC_SAR2_PATT_TAB1_REG,0xafffff); // Test internal voltage if the channel info is 0xa.
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REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_SAR1_PATT_LEN, 0);
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WRITE_PERI_REG(APB_SARADC_SAR1_PATT_TAB1_REG,0xafffff); // Test internal voltage if the channel info is 0xa.
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// Enable adc1 digital controller
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SET_PERI_REG_MASK(SENS_SAR_MEAS1_MUX_REG, SENS_SAR1_DIG_FORCE);
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// Set SARADC2 arbiter
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CLEAR_PERI_REG_MASK(SENS_SAR_MEAS2_MUX_REG, SENS_SAR2_RTC_FORCE);
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CLEAR_PERI_REG_MASK(APB_SARADC_APB_ADC_ARB_CTRL_REG, APB_SARADC_ADC_ARB_GRANT_FORCE);
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CLEAR_PERI_REG_MASK(APB_SARADC_APB_ADC_ARB_CTRL_REG, APB_SARADC_ADC_ARB_FIX_PRIORITY);
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// Disable ADC filter
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REG_SET_FIELD(APB_SARADC_FILTER_CTRL0_REG, APB_SARADC_FILTER_CHANNEL0, 0xD);
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REG_SET_FIELD(APB_SARADC_FILTER_CTRL0_REG, APB_SARADC_FILTER_CHANNEL1, 0xD);
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// Start ADC sample
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SET_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_SEL);
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SET_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_EN);
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/*Choose the appropriate internal voltage to measure*/
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENCAL_REF_ADDR, 1);
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_TSENS_ADDR, 1);
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_RTC_ADDR, 0);
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_DTEST_RTC_ADDR, 0);
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}
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//TODO: IDF-4714
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void bootloader_random_disable(void)
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{
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/* Restore internal I2C bus state */
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENCAL_REF_ADDR, 0);
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_TSENS_ADDR, 0);
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_RTC_ADDR, 0);
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REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_DTEST_RTC_ADDR, 0);
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//Power off SAR ADC
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REG_SET_FIELD(SENS_SAR_POWER_XPD_SAR_REG, SENS_FORCE_XPD_SAR, 0);
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//return to ADC RTC controller
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CLEAR_PERI_REG_MASK(SENS_SAR_MEAS1_MUX_REG, SENS_SAR1_DIG_FORCE);
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//Invalidate ADC digital trigger timer
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CLEAR_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_EN);
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//Disable ADC digital part
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CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
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//Hold reset bit for ADC digital part
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SET_PERI_REG_MASK(SYSTEM_PERIP_RST_EN0_REG, SYSTEM_APB_SARADC_RST);
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/* Note: the 8M CLK entropy source continues running even after this function is called,
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but as mentioned above it's better to enable Wi-Fi or BT or call bootloader_random_enable()
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in order to get a secondary entropy source.
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*/
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}
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