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