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feat (bootloader): added rng sampling

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Set maximum RNG query frequency to save value known from tests
This commit is contained in:
Jakob Hasse 2021-10-25 19:13:42 +08:00 committed by Mahavir Jain
parent 214d62b9ad
commit ee24264c75
5 changed files with 118 additions and 11 deletions
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1
components/bootloader/subproject/main/ld/esp32s3/bootloader.ld
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@ -30,7 +30,6 @@ SECTIONS
*libbootloader_support.a:bootloader_flash.*(.literal .text .literal.* .text.*)
*libbootloader_support.a:bootloader_random.*(.literal .text .literal.* .text.*)
*libbootloader_support.a:bootloader_random*.*(.literal.bootloader_random_disable .text.bootloader_random_disable)
*libbootloader_support.a:bootloader_random*.*(.literal.bootloader_random_enable .text.bootloader_random_enable)
*libesp_common.a:fpga_overrides.*(.literal.bootloader_fill_random .text.bootloader_fill_random)
*libbootloader_support.a:bootloader_efuse_esp32s3.*(.literal .text .literal.* .text.*)
*libbootloader_support.a:bootloader_utility.*(.literal .text .literal.* .text.*)

9
components/bootloader_support/src/bootloader_random.c
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@ -18,6 +18,13 @@
}
#else
#if !defined CONFIG_IDF_TARGET_ESP32S3
#define RNG_CPU_WAIT_CYCLE_NUM (80 * 32 * 2) /* extra factor of 2 is precautionary */
#else
#define RNG_CPU_WAIT_CYCLE_NUM (80 * 23) /* 45 KHz reading frequency is the maximum we have tested so far on S3 */
#endif
__attribute__((weak)) void bootloader_fill_random(void *buffer, size_t length)
{
uint8_t *buffer_bytes = (uint8_t *)buffer;
@ -40,7 +47,7 @@
do {
random ^= REG_READ(WDEV_RND_REG);
now = cpu_hal_get_cycle_count();
} while (now - start < 80 * 32 * 2); /* extra factor of 2 is precautionary */
} while (now - start < RNG_CPU_WAIT_CYCLE_NUM);
}
buffer_bytes[i] = random >> ((i % 4) * 8);
}

88
components/bootloader_support/src/bootloader_random_esp32s3.c
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@ -6,18 +6,92 @@
#include "sdkconfig.h"
#include "bootloader_random.h"
#include "esp_log.h"
static const char *TAG = "bootloader_random";
#include "soc/system_reg.h"
#include "soc/syscon_reg.h"
#include "soc/apb_saradc_reg.h"
#include "soc/rtc_cntl_reg.h"
#include "soc/sens_reg.h"
#include "regi2c_ctrl.h"
#include "regi2c_saradc.h"
void bootloader_random_enable(void)
{
ESP_LOGW(TAG, "RNG for ESP32-S3 not currently supported"); // IDF-1878
// Don't forget to remove the following line
// *libbootloader_support.a:bootloader_random*.*(.literal.bootloader_random_enable .text.bootloader_random_enable)
// In the bootloader.ld when RNG support is ready for ESP32-S3
SET_PERI_REG_MASK(SYSTEM_WIFI_CLK_EN_REG, SYSTEM_WIFI_CLK_RNG_EN);
// Enable 8M clock source for RNG (this is actually enough to produce strong random results,
// but enabling the SAR ADC as well adds some insurance.)
REG_SET_BIT(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_CLK8M_EN);
/// Enable SAR ADC to read a disconnected input for additional entropy
// Reset ADC clock
SET_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
// Enable clock and select clock source for ADC digital controller
REG_SET_FIELD(APB_SARADC_APB_ADC_CLKM_CONF_REG, APB_SARADC_CLK_SEL, 2); //APB clock
SET_PERI_REG_MASK(APB_SARADC_CTRL_REG, APB_SARADC_SAR_CLK_GATED);
SET_PERI_REG_MASK(APB_SARADC_APB_ADC_CLKM_CONF_REG, APB_SARADC_CLK_EN);
// Read freq = apb_clk / (APB_SARADC_CLKM_DIV_NUM + 1) / TIMER_TARGET / 2
// Internal ADC sample freq = apb_clk / (APB_SARADC_CLKM_DIV_NUM + 1) / (APB_SARADC_SAR_CLK_DIV + 1)
// Read frequency has to be at least 35 times lower than the sampling frequency
REG_SET_FIELD(APB_SARADC_APB_ADC_CLKM_CONF_REG, APB_SARADC_CLKM_DIV_NUM, 3);
REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_SAR_CLK_DIV, 3); // SAR clock divider has to be at least 2
REG_SET_FIELD(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_TARGET, 70);
CLEAR_PERI_REG_MASK(APB_SARADC_CTRL_REG, APB_SARADC_START_FORCE);
REG_SET_FIELD(SENS_SAR_POWER_XPD_SAR_REG, SENS_FORCE_XPD_SAR, 3);
CLEAR_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_MEAS_NUM_LIMIT);
REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_WORK_MODE, 1);
REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_SAR2_PATT_LEN, 0);
WRITE_PERI_REG(APB_SARADC_SAR2_PATT_TAB1_REG,0xafffff); // Test internal voltage if the channel info is 0xa.
REG_SET_FIELD(APB_SARADC_CTRL_REG, APB_SARADC_SAR1_PATT_LEN, 0);
WRITE_PERI_REG(APB_SARADC_SAR1_PATT_TAB1_REG,0xafffff); // Test internal voltage if the channel info is 0xa.
// Enable adc1 digital controller
SET_PERI_REG_MASK(SENS_SAR_MEAS1_MUX_REG, SENS_SAR1_DIG_FORCE);
// Set SARADC2 arbiter
CLEAR_PERI_REG_MASK(SENS_SAR_MEAS2_MUX_REG, SENS_SAR2_RTC_FORCE);
CLEAR_PERI_REG_MASK(APB_SARADC_APB_ADC_ARB_CTRL_REG, APB_SARADC_ADC_ARB_GRANT_FORCE);
CLEAR_PERI_REG_MASK(APB_SARADC_APB_ADC_ARB_CTRL_REG, APB_SARADC_ADC_ARB_FIX_PRIORITY);
// Disable ADC filter
REG_SET_FIELD(APB_SARADC_FILTER_CTRL0_REG, APB_SARADC_FILTER_CHANNEL0, 0xD);
REG_SET_FIELD(APB_SARADC_FILTER_CTRL0_REG, APB_SARADC_FILTER_CHANNEL1, 0xD);
// Start ADC sample
SET_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_SEL);
SET_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_EN);
/*Choose the appropriate internal voltage to measure*/
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENCAL_REF_ADDR, 1);
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_TSENS_ADDR, 1);
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_RTC_ADDR, 0);
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_DTEST_RTC_ADDR, 0);
}
void bootloader_random_disable(void)
{
ESP_LOGW(TAG, "RNG for ESP32-S3 not currently supported"); // IDF-1878
/* Restore internal I2C bus state */
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENCAL_REF_ADDR, 0);
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_TSENS_ADDR, 0);
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_ENT_RTC_ADDR, 0);
REGI2C_WRITE_MASK(I2C_SAR_ADC, ADC_SARADC_DTEST_RTC_ADDR, 0);
/* Restore SARADC to default mode */
CLEAR_PERI_REG_MASK(SENS_SAR_MEAS1_MUX_REG, SENS_SAR1_DIG_FORCE);
SET_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
REG_SET_FIELD(SENS_SAR_POWER_XPD_SAR_REG, SENS_FORCE_XPD_SAR, 0);
CLEAR_PERI_REG_MASK(APB_SARADC_CTRL2_REG, APB_SARADC_TIMER_EN);
CLEAR_PERI_REG_MASK(SENS_SAR_PERI_CLK_GATE_CONF_REG, SENS_SARADC_CLK_EN);
CLEAR_PERI_REG_MASK(SYSTEM_PERIP_CLK_EN0_REG, SYSTEM_APB_SARADC_CLK_EN);
/* Note: the 8M CLK entropy source continues running even after this function is called,
but as mentioned above it's better to enable Wi-Fi or BT or call bootloader_random_enable()
in order to get a secondary entropy source.
*/
}

9
components/esp_hw_support/hw_random.c
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@ -25,6 +25,13 @@
#include "esp32h2/clk.h"
#endif
#if defined CONFIG_IDF_TARGET_ESP32S3
#define APB_CYCLE_WAIT_NUM (1778) /* If APB clock is 80 MHz, maximum sampling frequency is around 45 KHz*/
/* 45 KHz reading frequency is the maximum we have tested so far on S3 */
#else
#define APB_CYCLE_WAIT_NUM (16)
#endif
uint32_t IRAM_ATTR esp_random(void)
{
/* The PRNG which implements WDEV_RANDOM register gets 2 bits
@ -53,7 +60,7 @@ uint32_t IRAM_ATTR esp_random(void)
do {
ccount = cpu_hal_get_cycle_count();
result ^= REG_READ(WDEV_RND_REG);
} while (ccount - last_ccount < cpu_to_apb_freq_ratio * 16);
} while (ccount - last_ccount < cpu_to_apb_freq_ratio * APB_CYCLE_WAIT_NUM);
last_ccount = ccount;
return result ^ REG_READ(WDEV_RND_REG);
}

22
components/esp_hw_support/port/esp32s3/private_include/regi2c_saradc.h
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@ -16,7 +16,7 @@
*/
#define I2C_SAR_ADC 0X69
#define I2C_SAR_ADC_HOSTID 0
#define I2C_SAR_ADC_HOSTID 1
#define ADC_SAR1_ENCAL_GND_ADDR 0x7
#define ADC_SAR1_ENCAL_GND_ADDR_MSB 5
@ -53,3 +53,23 @@
#define ADC_SAR1_SAMPLE_CYCLE_ADDR 0x2
#define ADC_SAR1_SAMPLE_CYCLE_ADDR_MSB 0x2
#define ADC_SAR1_SAMPLE_CYCLE_ADDR_LSB 0x0
#define ADC_SARADC_DTEST_RTC_ADDR 0x7
#define ADC_SARADC_DTEST_RTC_ADDR_MSB 1
#define ADC_SARADC_DTEST_RTC_ADDR_LSB 0
#define ADC_SARADC_ENT_TSENS_ADDR 0x7
#define ADC_SARADC_ENT_TSENS_ADDR_MSB 2
#define ADC_SARADC_ENT_TSENS_ADDR_LSB 2
#define ADC_SARADC_ENT_RTC_ADDR 0x7
#define ADC_SARADC_ENT_RTC_ADDR_MSB 3
#define ADC_SARADC_ENT_RTC_ADDR_LSB 3
#define ADC_SARADC_ENCAL_REF_ADDR 0x7
#define ADC_SARADC_ENCAL_REF_ADDR_MSB 4
#define ADC_SARADC_ENCAL_REF_ADDR_LSB 4
#define I2C_SARADC_TSENS_DAC 0x6
#define I2C_SARADC_TSENS_DAC_MSB 3
#define I2C_SARADC_TSENS_DAC_LSB 0