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drivers: platform: maxim: max32657: Add CAPI TRNG driver
Add the implementation for the CAPI TRNG driver Signed-off-by: Ramon Miguel Imbao <ramonmiguel.imbao@analog.com>
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‎capi/platform/maxim/max32657/maxim_capi_trng.c‎

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/*******************************************************************************
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* @file maxim_capi_trng.c
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* @brief Implementation of TRNG functions
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* @author Ramon Miguel Imbao (ramonmiguel.imbao@analog.com)
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********************************************************************************
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* Copyright 2026(c) Analog Devices, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. Neither the name of Analog Devices, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES, INC. “AS IS” AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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* EVENT SHALL ANALOG DEVICES, INC. BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*******************************************************************************/
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#include <stdlib.h>
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#include <errno.h>
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#include "capi_trng.h"
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#include "maxim_capi_trng.h"
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#include "maxim_capi_irq.h"
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#include "trng.h"
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#include "max32657.h"
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/** Static variables **********************************************************/
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static struct capi_trng_handle *trng = NULL;
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/** Forward declarations ******************************************************/
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void max_capi_trng_isr(void *handle);
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/** Helper functions **********************************************************/
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/**
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* @brief Callback function to pass to MXC_TRNG_RandomAsync
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* @param req MSDK-managed parameter (not used)
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* @param result The result of the callback
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*/
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static void _max_capi_trng_msdk_callback(void *req, int result)
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{
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struct max_capi_trng_priv *trng_priv;
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enum capi_trng_async_event event;
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if (!trng || !trng->priv)
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return;
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trng_priv = trng->priv;
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if (trng_priv->callback) {
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event = (result == E_NO_ERROR)
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? CAPI_TRNG_EVENT_GENERATION_COMPLETE
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: CAPI_TRNG_EVENT_ERROR;
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trng_priv->callback(event, trng_priv->callback_arg, result);
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}
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}
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/** Function implementations **************************************************/
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/**
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* @brief Initialize the TRNG peripheral
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* @param handle Pointer to the TRNG handle
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* @param config Configuration struct
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_init(struct capi_trng_handle **handle,
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const struct capi_trng_config *config)
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{
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int ret;
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struct capi_trng_handle *trng_handle;
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struct max_capi_trng_priv *trng_priv;
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if (!handle || !config)
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return -EINVAL;
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if (config->identifier != 0)
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return -EINVAL;
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if (trng != NULL) {
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*handle = trng;
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return 0;
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}
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if (*handle == NULL) {
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trng_handle = capi_calloc(1, sizeof(*trng_handle));
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if (!trng_handle)
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return -ENOMEM;
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trng_handle->init_allocated = true;
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} else {
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trng_handle = *handle;
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trng_handle->init_allocated = false;
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}
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trng_priv = capi_calloc(1, sizeof(*trng_priv));
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if (!trng_priv) {
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ret = -ENOMEM;
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goto free_handle;
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}
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trng_handle->priv = trng_priv;
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trng_handle->ops = config->ops;
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ret = MXC_TRNG_Init();
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if (ret)
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goto free_priv;
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struct capi_irq_config irq_config = {
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.irq_ctrl_id = 0,
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};
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ret = capi_irq_init(&irq_config);
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if (ret)
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goto free_priv;
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ret = capi_irq_connect(TRNG_IRQn, max_capi_trng_isr, trng_handle);
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if (ret)
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goto free_priv;
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ret = capi_irq_set_priority(TRNG_IRQn, config->irq_priority);
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if (ret)
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goto disconnect_irq;
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ret = capi_irq_enable(TRNG_IRQn);
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if (ret)
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goto disconnect_irq;
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trng = trng_handle;
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*handle = trng_handle;
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return 0;
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disconnect_irq:
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capi_irq_connect(TRNG_IRQn, NULL, NULL);
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free_priv:
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MXC_TRNG_Shutdown();
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capi_free(trng_priv);
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free_handle:
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if (trng_handle->init_allocated)
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capi_free(trng_handle);
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trng = NULL;
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return ret;
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}
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/**
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* @brief Deinitialize the TRNG peripheral
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* @param handle The TRNG handle
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_deinit(struct capi_trng_handle *handle)
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{
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int ret;
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struct max_capi_trng_priv *trng_priv;
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if (!handle || !handle->priv)
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return -EINVAL;
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trng_priv = handle->priv;
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capi_irq_disable(TRNG_IRQn);
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capi_irq_connect(TRNG_IRQn, NULL, NULL);
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ret = MXC_TRNG_Shutdown();
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capi_free(handle->priv);
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if (handle->init_allocated)
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capi_free(handle);
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trng = NULL;
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return ret;
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}
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/**
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* @brief Generate an unsigned 32-bit number (blocking)
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* @param handle The TRNG handle
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* @param value Where to store the unsigned 32-bit number
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_generate_u32(struct capi_trng_handle *handle, uint32_t *value)
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{
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if (!handle || !handle->priv || !value)
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return -EINVAL;
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*value = (uint32_t)MXC_TRNG_RandomInt();
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return 0;
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}
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/**
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* @brief Fill a buffer with random bytes (blocking)
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* @param handle The TRNG handle
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* @param buffer The data buffer to store bytes to
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* @param length The length of the buffer
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_fill_buffer(struct capi_trng_handle *handle, uint8_t *buffer,
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uint32_t length)
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{
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int ret;
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if (!handle || !handle->priv || !buffer)
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return -EINVAL;
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if (length == 0)
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return -EINVAL;
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ret = MXC_TRNG_Random(buffer, length);
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if (ret != E_NO_ERROR)
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return -EINVAL;
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return 0;
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}
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/**
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* @brief Fill a buffer with random bytes (non-blocking)
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* @param handle The TRNG handle
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* @param buffer The data buffer to store bytes to
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* @param length The length of the buffer
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_fill_buffer_async(struct capi_trng_handle *handle,
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uint8_t *buffer, uint32_t length)
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{
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if (!handle || !handle->priv || !buffer)
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return -EINVAL;
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if (length == 0)
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return -EINVAL;
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MXC_TRNG_RandomAsync(buffer, length, _max_capi_trng_msdk_callback);
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return 0;
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}
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/**
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* @brief Register a callback
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* @param handle The TRNG handle
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* @param callback The callback function
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* @param callback_arg The callback function argument
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_register_callback(struct capi_trng_handle *handle,
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capi_trng_callback_t callback,
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void *callback_arg)
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{
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struct max_capi_trng_priv *trng_priv;
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if (!handle || !handle->priv)
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return -EINVAL;
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trng_priv = handle->priv;
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trng_priv->callback = callback;
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trng_priv->callback_arg = callback_arg;
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return 0;
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}
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/**
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* @brief Perform entropy source health test
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* @param handle The TRNG handle
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* @return 0 on success, negative error code otherwise
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*/
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int max_capi_trng_health_test(struct capi_trng_handle *handle)
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{
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int ret;
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if (!handle || !handle->priv)
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return -EINVAL;
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ret = MXC_TRNG_HealthTest();
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if (ret != E_NO_ERROR)
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return -EINVAL;
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return 0;
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}
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/**
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* @brief Interrupt handler for the TRNG peripheral
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* @param handle The TRNG handle
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*/
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void max_capi_trng_isr(void *handle)
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{
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struct capi_trng_handle *trng_handle = (struct capi_trng_handle *)handle;
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if (!trng_handle || !trng_handle->priv)
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return;
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MXC_TRNG_Handler();
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}
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const struct capi_trng_ops max_capi_trng_ops = {
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.init = max_capi_trng_init,
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.deinit = max_capi_trng_deinit,
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.generate_u32 = max_capi_trng_generate_u32,
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.fill_buffer = max_capi_trng_fill_buffer,
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.fill_buffer_async = max_capi_trng_fill_buffer_async,
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.register_callback = max_capi_trng_register_callback,
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.health_test = max_capi_trng_health_test,
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.isr = max_capi_trng_isr,
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};
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‎capi/platform/maxim/max32657/maxim_capi_trng.h‎

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/*******************************************************************************
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* @file maxim_capi_trng.h
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* @brief Header file for TRNG functions
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* @author Ramon Miguel Imbao (ramonmiguel.imbao@analog.com)
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********************************************************************************
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* Copyright 2026(c) Analog Devices, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
9+
* modification, are permitted provided that the following conditions are met:
10+
*
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* 1. Redistributions of source code must retain the above copyright notice,
12+
* this list of conditions and the following disclaimer.
13+
*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
15+
* this list of conditions and the following disclaimer in the documentation
16+
* and/or other materials provided with the distribution.
17+
*
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* 3. Neither the name of Analog Devices, Inc. nor the names of its
19+
* contributors may be used to endorse or promote products derived from this
20+
* software without specific prior written permission.
21+
*
22+
* THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES, INC. “AS IS” AND ANY EXPRESS OR
23+
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24+
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
25+
* EVENT SHALL ANALOG DEVICES, INC. BE LIABLE FOR ANY DIRECT, INDIRECT,
26+
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27+
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
28+
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29+
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30+
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
31+
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*******************************************************************************/
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#ifndef MAXIM_CAPI_TRNG_H_
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#define MAXIM_CAPI_TRNG_H_
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#include "capi_trng.h"
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#include "capi_irq.h"
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struct max_capi_trng_priv {
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/** Callback function for async */
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capi_trng_callback_t callback;
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/** Callback argument for async */
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void *callback_arg;
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};
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extern const struct capi_trng_ops max_capi_trng_ops;
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#endif /* MAXIM_CAPI_TRNG_H_ */

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