drivers: entropy: sy1xx add support for trng (8d07f6b4) · Commits · Wenxi XU / zephyr

drivers/entropy/CMakeLists.txt

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		@@ -36,5 +36,6 @@ zephyr_library_sources_ifdef(CONFIG_ENTROPY_PSA_CRYPTO_RNG entropy_psa_crypto.c
		zephyr_library_sources_ifdef(CONFIG_ENTROPY_NPCX_DRBG entropy_npcx_drbg.c)
		zephyr_library_sources_ifdef(CONFIG_ENTROPY_MAX32_TRNG entropy_max32.c)
		zephyr_library_sources_ifdef(CONFIG_ENTROPY_RENESAS_RA entropy_renesas_ra.c)
		zephyr_library_sources_ifdef(CONFIG_ENTROPY_SY1XX_TRNG entropy_sy1xx_trng.c)

		zephyr_library_link_libraries_ifdef(CONFIG_BUILD_WITH_TFM tfm_api)

drivers/entropy/Kconfig

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		@@ -39,6 +39,7 @@ source "drivers/entropy/Kconfig.psa_crypto"
		source "drivers/entropy/Kconfig.npcx"
		source "drivers/entropy/Kconfig.max32"
		source "drivers/entropy/Kconfig.renesas_ra"
		source "drivers/entropy/Kconfig.sy1xx"

		config ENTROPY_HAS_DRIVER
		bool

drivers/entropy/Kconfig.sy1xx

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		# Copyright (c) 2025 sensry.io
		# SPDX-License-Identifier: Apache-2.0

		config ENTROPY_SY1XX_TRNG
		bool "Sensry sy1xx soc family true random number generator (TRNG) driver"
		default y
		depends on DT_HAS_SENSRY_SY1XX_TRNG_ENABLED
		select ENTROPY_HAS_DRIVER

drivers/entropy/entropy_sy1xx_trng.c

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		/*
		* Copyright (c) 2025 sensry.io
		*
		* SPDX-License-Identifier: Apache-2.0
		*/

		#define DT_DRV_COMPAT sensry_sy1xx_trng

		#include <zephyr/logging/log.h>
		LOG_MODULE_REGISTER(sy1xx_entropy, CONFIG_ENTROPY_LOG_LEVEL);

		#include <zephyr/device.h>
		#include <zephyr/drivers/entropy.h>
		#include <errno.h>
		#include <zephyr/init.h>
		#include <zephyr/kernel.h>

		#define SY1XX_TRNG_VAL_OFFS 0x00
		#define SY1XX_TRNG_FIFO_COUNT_OFFS 0x04
		#define SY1XX_TRNG_STATUS_OFFS 0x08
		#define SY1XX_TRNG_ERROR_OFFS 0x0c

		#define SY1XX_TRNG_FIFO_SIZE 64

		/* time needed to fill fifo when empty */
		#define SY1XX_TRNG_FIFO_REFILL_TIME_USEC 80
		#define SY1XX_TRNG_FIFO_REFILL_MAX_RETRIES 5

		struct sy1xx_trng_config {
		uint32_t base_addr;
		};

		struct sy1xx_trng_data {
		struct k_mutex mutex;
		};

		static int sy1xx_trng_driver_init(const struct device *dev)
		{
		const struct sy1xx_trng_config *const cfg = dev->config;
		struct sy1xx_trng_data *const data = dev->data;

		k_mutex_init(&data->mutex);

		/* trng comes up fully initialized, so only check if all is fine */
		if (0 != sys_read32(cfg->base_addr + SY1XX_TRNG_ERROR_OFFS)) {
		LOG_ERR("failure mode active, internal init failed");
		return -EINVAL;
		}

		if (SY1XX_TRNG_FIFO_SIZE != sys_read32(cfg->base_addr + SY1XX_TRNG_FIFO_COUNT_OFFS)) {
		LOG_ERR("fifo not fully loaded");
		return -EINVAL;
		}

		return 0;
		}

		static int sy1xx_trng_driver_get_entropy(const struct device dev, uint8_t buffer, uint16_t length)
		{
		const struct sy1xx_trng_config *const cfg = dev->config;
		struct sy1xx_trng_data *const data = dev->data;
		uint32_t retries_left;
		uint32_t random_word;

		uint32_t word_count = DIV_ROUND_UP(length, 4);

		for (uint32_t i = 0; i < word_count; i++) {
		retries_left = SY1XX_TRNG_FIFO_REFILL_MAX_RETRIES;

		k_mutex_lock(&data->mutex, K_FOREVER);
		while (true) {
		/* make sure fifo has at least one random word */
		if (sys_read32(cfg->base_addr + SY1XX_TRNG_FIFO_COUNT_OFFS) > 0) {
		/* get new random word */
		random_word = sys_read32(cfg->base_addr + SY1XX_TRNG_VAL_OFFS);
		break;
		}

		/* currently no random values available, thus wait */
		retries_left--;
		if (!retries_left) {
		/* number of retries exhausted, give up */
		k_mutex_unlock(&data->mutex);
		return -ETIMEDOUT;
		}
		k_sleep(K_USEC(SY1XX_TRNG_FIFO_REFILL_TIME_USEC));
		};
		k_mutex_unlock(&data->mutex);

		memcpy(&buffer[i * 4], &random_word, MIN(length, 4));
		length -= 4;
		}

		/* always error check, to make sure that we received valid readings */
		if (0 != sys_read32(cfg->base_addr + SY1XX_TRNG_ERROR_OFFS)) {
		LOG_ERR("failure mode active, reading of values failed");
		return -EINVAL;
		}

		return 0;
		}

		static int sy1xx_trng_driver_get_entropy_isr(const struct device dev, uint8_t buffer,
		uint16_t length, uint32_t flags)
		{

		const struct sy1xx_trng_config *const cfg = dev->config;
		unsigned int key;
		uint32_t random_word;
		int ret;

		uint32_t word_count = DIV_ROUND_UP(length, 4);

		for (uint32_t i = 0; i < word_count; i++) {

		do {
		key = irq_lock();
		/* make sure fifo has at least one random word */
		if (sys_read32(cfg->base_addr + SY1XX_TRNG_FIFO_COUNT_OFFS) > 0) {
		/* get new random word */
		random_word = sys_read32(cfg->base_addr + SY1XX_TRNG_VAL_OFFS);
		ret = 0;
		} else {
		ret = -EAGAIN;
		}
		irq_unlock(key);

		if (ret && !(flags & ENTROPY_BUSYWAIT)) {
		/* no waiting allowed */
		return ret;
		}

		} while (ret);

		memcpy(&buffer[i * 4], &random_word, MIN(length, 4));
		length -= 4;
		}

		/* always error check, to make sure that we received valid readings */
		if (0 != sys_read32(cfg->base_addr + SY1XX_TRNG_ERROR_OFFS)) {
		LOG_ERR("failure mode active, reading of values failed");
		return -EINVAL;
		}

		return 0;
		}

		static DEVICE_API(entropy,
		sy1xx_entropy_api) = {.get_entropy = sy1xx_trng_driver_get_entropy,
		.get_entropy_isr = sy1xx_trng_driver_get_entropy_isr};

		#define SY1XX_TRNG_INIT(n) \
		\
		static const struct sy1xx_trng_config sy1xx_trng##n##_cfg = { \
		.base_addr = (uint32_t)DT_INST_REG_ADDR(n), \
		}; \
		\
		static struct sy1xx_trng_data sy1xx_trng##n##_data = {}; \
		\
		DEVICE_DT_INST_DEFINE(n, sy1xx_trng_driver_init, NULL, &sy1xx_trng##n##_data, \
		&sy1xx_trng##n##_cfg, PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY, \
		&sy1xx_entropy_api);

		DT_INST_FOREACH_STATUS_OKAY(SY1XX_TRNG_INIT)

dts/bindings/rng/sensry,sy1xx-trng.yaml

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		# Copyright (c) 2025 sensry.io
		# SPDX-License-Identifier: Apache-2.0

		description: Sensry SY1XX TRNG node

		compatible: "sensry,sy1xx-trng"

		include: base.yaml

		properties:
		reg:
		required: true

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