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drivers: entropy: sy1xx add support for trng

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Add entropy support for the sensry soc sy1xx, based
on trng.

Signed-off-by: Sven Ginka <s.ginka@sensry.de>
This commit is contained in:
Sven Ginka
2025-01-20 15:52:36 +01:00
committed by Benjamin Cabé
parent 9be79bc145
commit 8d07f6b4d6
5 changed files with 186 additions and 0 deletions
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1
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)

1
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

8
drivers/entropy/Kconfig.sy1xx Normal file
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@@ -0,0 +1,8 @@
# 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

164
drivers/entropy/entropy_sy1xx_trng.c Normal file
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@@ -0,0 +1,164 @@
/*
* 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)

12
dts/bindings/rng/sensry,sy1xx-trng.yaml Normal file
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@@ -0,0 +1,12 @@
# 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