blob: 586b2137ff30e6561767e57561eb3caf052a8a59 [file] [log] [blame]
/*
* Copyright 2022, NXP
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT nxp_imx_caam
#include <zephyr/device.h>
#include <zephyr/drivers/entropy.h>
#include <zephyr/random/random.h>
#include <zephyr/init.h>
#include <zephyr/kernel.h>
#include "fsl_caam.h"
struct mcux_entropy_config {
CAAM_Type *base;
};
static caam_job_ring_interface_t jrif0 __attribute__((__section__(".nocache")));
static uint8_t rng_buff_pool[CONFIG_ENTRY_MCUX_CAAM_POOL_SIZE]
__attribute__((__section__(".nocache")));
/* This semaphore is needed to prevent race condition to static variables in the HAL driver */
K_SEM_DEFINE(mcux_caam_sem, 1, 1)
static int entropy_mcux_caam_get_entropy(const struct device *dev,
uint8_t *buffer,
uint16_t length)
{
const struct mcux_entropy_config *config = dev->config;
status_t status;
caam_handle_t handle;
uint16_t read_length = 0;
uint16_t insert_idx = 0;
int ret = 0;
k_timeout_t sem_timeout = K_MSEC(10);
handle.jobRing = kCAAM_JobRing0;
/*
* The buffer passed to the CAAM RNG function needs to be in non-cache
* memory. Use an intermediate buffer to stage the data to the user
* buffer.
*/
while (insert_idx < length) {
read_length = MIN(sizeof(rng_buff_pool), (length - insert_idx));
ret = k_sem_take(&mcux_caam_sem, sem_timeout);
if (ret) {
return ret;
}
status = CAAM_RNG_GetRandomData(
config->base, &handle, kCAAM_RngStateHandle0,
&rng_buff_pool[0], read_length, kCAAM_RngDataAny, NULL);
k_sem_give(&mcux_caam_sem);
memcpy(&buffer[insert_idx], &rng_buff_pool[0], read_length);
insert_idx += read_length;
}
return 0;
}
static const struct entropy_driver_api entropy_mcux_caam_api_funcs = {
.get_entropy = entropy_mcux_caam_get_entropy
};
static const struct mcux_entropy_config entropy_mcux_config = {
.base = (CAAM_Type *)DT_INST_REG_ADDR(0)
};
static int entropy_mcux_caam_init(const struct device *dev)
{
const struct mcux_entropy_config *config = dev->config;
caam_config_t conf;
status_t status;
CAAM_GetDefaultConfig(&conf);
conf.jobRingInterface[0] = &jrif0;
status = CAAM_Init(config->base, &conf);
__ASSERT_NO_MSG(!status);
if (status != 0) {
return -ENODEV;
}
return 0;
}
DEVICE_DT_INST_DEFINE(0,
entropy_mcux_caam_init, NULL, NULL,
&entropy_mcux_config,
PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY,
&entropy_mcux_caam_api_funcs);