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drivers: entropy: sy1xx add support for trng
Add entropy support for the sensry soc sy1xx, based on trng. Signed-off-by: Sven Ginka <[email protected]>
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‎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
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_NPCX_DRBG entropy_npcx_drbg.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_MAX32_TRNG entropy_max32.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_RENESAS_RA entropy_renesas_ra.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_SY1XX_TRNG entropy_sy1xx_trng.c)
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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"
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source "drivers/entropy/Kconfig.npcx"
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source "drivers/entropy/Kconfig.max32"
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source "drivers/entropy/Kconfig.renesas_ra"
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source "drivers/entropy/Kconfig.sy1xx"
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config ENTROPY_HAS_DRIVER
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bool

‎drivers/entropy/Kconfig.sy1xx

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# Copyright (c) 2025 sensry.io
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# SPDX-License-Identifier: Apache-2.0
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config ENTROPY_SY1XX_TRNG
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bool "Sensry sy1xx soc family true random number generator (TRNG) driver"
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default y
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depends on DT_HAS_SENSRY_SY1XX_TRNG_ENABLED
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select ENTROPY_HAS_DRIVER

‎drivers/entropy/entropy_sy1xx_trng.c

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/*
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* Copyright (c) 2025 sensry.io
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT sensry_sy1xx_trng
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#include <zephyr/logging/log.h>
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LOG_MODULE_REGISTER(sy1xx_entropy, CONFIG_ENTROPY_LOG_LEVEL);
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#include <zephyr/device.h>
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#include <zephyr/drivers/entropy.h>
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#include <errno.h>
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#include <zephyr/init.h>
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#include <zephyr/kernel.h>
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#define SY1XX_TRNG_VAL_OFFS 0x00
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#define SY1XX_TRNG_FIFO_COUNT_OFFS 0x04
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#define SY1XX_TRNG_STATUS_OFFS 0x08
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#define SY1XX_TRNG_ERROR_OFFS 0x0c
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#define SY1XX_TRNG_FIFO_SIZE 64
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/* time needed to fill fifo when empty */
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#define SY1XX_TRNG_FIFO_REFILL_TIME_USEC 80
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#define SY1XX_TRNG_FIFO_REFILL_MAX_RETRIES 5
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struct sy1xx_trng_config {
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uint32_t base_addr;
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};
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struct sy1xx_trng_data {
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struct k_mutex mutex;
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};
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static int sy1xx_trng_driver_init(const struct device *dev)
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{
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const struct sy1xx_trng_config *const cfg = dev->config;
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struct sy1xx_trng_data *const data = dev->data;
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k_mutex_init(&data->mutex);
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/* trng comes up fully initialized, so only check if all is fine */
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if (0 != sys_read32(cfg->base_addr + SY1XX_TRNG_ERROR_OFFS)) {
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LOG_ERR("failure mode active, internal init failed");
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return -EINVAL;
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}
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if (SY1XX_TRNG_FIFO_SIZE != sys_read32(cfg->base_addr + SY1XX_TRNG_FIFO_COUNT_OFFS)) {
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LOG_ERR("fifo not fully loaded");
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return -EINVAL;
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}
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return 0;
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}
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static int sy1xx_trng_driver_get_entropy(const struct device *dev, uint8_t *buffer, uint16_t length)
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{
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const struct sy1xx_trng_config *const cfg = dev->config;
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struct sy1xx_trng_data *const data = dev->data;
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uint32_t retries_left;
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uint32_t random_word;
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uint32_t word_count = DIV_ROUND_UP(length, 4);
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for (uint32_t i = 0; i < word_count; i++) {
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retries_left = SY1XX_TRNG_FIFO_REFILL_MAX_RETRIES;
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k_mutex_lock(&data->mutex, K_FOREVER);
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while (true) {
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/* make sure fifo has at least one random word */
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if (sys_read32(cfg->base_addr + SY1XX_TRNG_FIFO_COUNT_OFFS) > 0) {
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/* get new random word */
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random_word = sys_read32(cfg->base_addr + SY1XX_TRNG_VAL_OFFS);
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break;
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}
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/* currently no random values available, thus wait */
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retries_left--;
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if (!retries_left) {
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/* number of retries exhausted, give up */
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k_mutex_unlock(&data->mutex);
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return -ETIMEDOUT;
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}
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k_sleep(K_USEC(SY1XX_TRNG_FIFO_REFILL_TIME_USEC));
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};
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k_mutex_unlock(&data->mutex);
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memcpy(&buffer[i * 4], &random_word, MIN(length, 4));
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length -= 4;
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}
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/* always error check, to make sure that we received valid readings */
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if (0 != sys_read32(cfg->base_addr + SY1XX_TRNG_ERROR_OFFS)) {
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LOG_ERR("failure mode active, reading of values failed");
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return -EINVAL;
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}
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return 0;
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}
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static int sy1xx_trng_driver_get_entropy_isr(const struct device *dev, uint8_t *buffer,
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uint16_t length, uint32_t flags)
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{
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const struct sy1xx_trng_config *const cfg = dev->config;
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unsigned int key;
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uint32_t random_word;
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int ret;
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uint32_t word_count = DIV_ROUND_UP(length, 4);
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for (uint32_t i = 0; i < word_count; i++) {
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do {
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key = irq_lock();
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/* make sure fifo has at least one random word */
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if (sys_read32(cfg->base_addr + SY1XX_TRNG_FIFO_COUNT_OFFS) > 0) {
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/* get new random word */
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random_word = sys_read32(cfg->base_addr + SY1XX_TRNG_VAL_OFFS);
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ret = 0;
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} else {
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ret = -EAGAIN;
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}
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irq_unlock(key);
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if (ret && !(flags & ENTROPY_BUSYWAIT)) {
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/* no waiting allowed */
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return ret;
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}
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} while (ret);
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memcpy(&buffer[i * 4], &random_word, MIN(length, 4));
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length -= 4;
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}
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/* always error check, to make sure that we received valid readings */
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if (0 != sys_read32(cfg->base_addr + SY1XX_TRNG_ERROR_OFFS)) {
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LOG_ERR("failure mode active, reading of values failed");
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return -EINVAL;
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}
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return 0;
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}
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static DEVICE_API(entropy,
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sy1xx_entropy_api) = {.get_entropy = sy1xx_trng_driver_get_entropy,
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.get_entropy_isr = sy1xx_trng_driver_get_entropy_isr};
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#define SY1XX_TRNG_INIT(n) \
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\
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static const struct sy1xx_trng_config sy1xx_trng##n##_cfg = { \
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.base_addr = (uint32_t)DT_INST_REG_ADDR(n), \
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}; \
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\
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static struct sy1xx_trng_data sy1xx_trng##n##_data = {}; \
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\
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DEVICE_DT_INST_DEFINE(n, sy1xx_trng_driver_init, NULL, &sy1xx_trng##n##_data, \
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&sy1xx_trng##n##_cfg, PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY, \
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&sy1xx_entropy_api);
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DT_INST_FOREACH_STATUS_OKAY(SY1XX_TRNG_INIT)

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

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# Copyright (c) 2025 sensry.io
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# SPDX-License-Identifier: Apache-2.0
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description: Sensry SY1XX TRNG node
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compatible: "sensry,sy1xx-trng"
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include: base.yaml
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properties:
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reg:
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required: true

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