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drivers: entropy: update espressif source

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Update entropy driver to add proper ESP32-S3 waiting cycles.
Add custow ESP32C6 waiting cycles and handle LP_TIMER support.

Signed-off-by: Sylvio Alves <sylvio.alves@espressif.com>
This commit is contained in:
Sylvio Alves 2025-01-10 09:32:53 -03:00 committed by Benjamin Cabé
parent b612044a93
commit c93a4b99ca
1 changed files with 36 additions and 5 deletions
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43
drivers/entropy/entropy_esp32.c
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@ -20,6 +20,26 @@
LOG_MODULE_REGISTER(entropy, CONFIG_ENTROPY_LOG_LEVEL);
#if SOC_LP_TIMER_SUPPORTED
#include "hal/lp_timer_hal.h"
#endif
#if defined CONFIG_SOC_SERIES_ESP32S3
/* If APB clock is 80 MHz, the maximum sampling frequency is around 45 KHz */
/* 45 KHz reading frequency is the maximum we have tested so far on S3 */
#define APB_CYCLE_WAIT_NUM (1778)
#elif defined CONFIG_SOC_SERIES_ESP32C6
/* On ESP32C6, we only read one byte at a time, then XOR the value with
* an asynchronous timer (see code below).
* The current value translates to a sampling frequency of around 62.5 KHz
* for reading 8 bit samples, which is the rate at which the RNG was tested,
* plus additional overhead for the calculation, making it slower.
*/
#define APB_CYCLE_WAIT_NUM (160 * 16)
#else
#define APB_CYCLE_WAIT_NUM (16)
#endif
static inline uint32_t entropy_esp32_get_u32(void)
{
/* The PRNG which implements WDEV_RANDOM register gets 2 bits
@ -30,18 +50,29 @@ static inline uint32_t entropy_esp32_get_u32(void)
* wait a bit longer due to extra time spent in arithmetic and branch statements.
*/
uint32_t cpu_to_apb_freq_ratio =
esp_clk_cpu_freq() / esp_clk_apb_freq();
uint32_t cpu_to_apb_freq_ratio = esp_clk_cpu_freq() / esp_clk_apb_freq();
static uint32_t last_ccount;
uint32_t ccount;
uint32_t result = 0;
#if SOC_LP_TIMER_SUPPORTED
for (size_t i = 0; i < sizeof(result); i++) {
do {
ccount = esp_cpu_get_cycle_count();
} while (ccount - last_ccount < cpu_to_apb_freq_ratio * 16);
last_ccount = ccount;
result ^= REG_READ(WDEV_RND_REG);
} while (ccount - last_ccount < cpu_to_apb_freq_ratio * APB_CYCLE_WAIT_NUM);
uint32_t current_rtc_timer_counter = (lp_timer_hal_get_cycle_count() & 0xFF);
return REG_READ(WDEV_RND_REG);
result ^= ((result ^ current_rtc_timer_counter) & 0xFF) << (i * 8);
}
#else
do {
ccount = esp_cpu_get_cycle_count();
result ^= REG_READ(WDEV_RND_REG);
} while (ccount - last_ccount < cpu_to_apb_freq_ratio * APB_CYCLE_WAIT_NUM);
#endif
last_ccount = ccount;
return result ^ REG_READ(WDEV_RND_REG);
}
static int entropy_esp32_get_entropy(const struct device *dev, uint8_t *buf,