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/**
* \file
*
* \brief SAM True Random Number Generator (TRNG) Driver
*
* Copyright (C) 2014-2016 Atmel Corporation. All rights reserved.
*
* \asf_license_start
*
* \page License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name of Atmel may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an
* Atmel microcontroller product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* \asf_license_stop
*
*/
/*
* Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
*/
#include "trng_callback.h"
#include "system_interrupt.h"
struct trng_module *_trng_instance;
/**
* \brief Registers a callback
*
* Registers a callback function which is implemented by the user.
*
* \note The callback must be enabled by \ref trng_enable_callback,
* in order for the interrupt handler to call it when the conditions for the
* callback type is met.
*
* \param[in] module Pointer to TC software instance struct
* \param[in] callback_func Pointer to callback function
* \param[in] callback_type Callback type given by an enum
*
* \retval STATUS_OK The function exited successfully
*/
enum status_code trng_register_callback(
struct trng_module *const module,
trng_callback_t callback_func,
const enum trng_callback callback_type)
{
/* Sanity check arguments */
Assert(module);
Assert(callback_func);
/* Register callback function */
module->callback[callback_type] = callback_func;
/* Set the bit corresponding to the callback_type */
module->register_callback_mask |= (1 << callback_type);
/* Enable interrupt for this TRNG module */
system_interrupt_enable(SYSTEM_INTERRUPT_MODULE_TRNG);
return STATUS_OK;
}
/**
* \brief Unregisters a callback
*
* Unregisters a callback function implemented by the user. The callback should be
* disabled before it is unregistered.
*
* \param[in] module Pointer to TC software instance struct
* \param[in] callback_type Callback type given by an enum
*
* \retval STATUS_OK The function exited successfully
*/
enum status_code trng_unregister_callback(
struct trng_module *const module,
const enum trng_callback callback_type)
{
/* Sanity check arguments */
Assert(module);
/* Unregister callback function */
module->callback[callback_type] = NULL;
/* Clear the bit corresponding to the callback_type */
module->register_callback_mask &= ~(1 << callback_type);
/* Disable interrupt for this TRNG module */
if (module->register_callback_mask == 0) {
system_interrupt_disable(SYSTEM_INTERRUPT_MODULE_TRNG);
}
return STATUS_OK;
}
/**
* \internal ISR handler for TRNG
*
* TRNG interrupt handler for random data ready.
*/
void TRNG_Handler(void)
{
/* Temporary variable */
uint8_t interrupt_and_callback_status_mask;
/* Get device instance from the look-up table */
struct trng_module *module = _trng_instance;
/* Read and mask interrupt flag register */
interrupt_and_callback_status_mask = module->hw->INTFLAG.reg &
(module->register_callback_mask & module->enable_callback_mask);
/* Check if data ready needs to be serviced */
if (interrupt_and_callback_status_mask & TRNG_INTFLAG_DATARDY) {
/* Store random result in job buffer (it will clear data ready flag) */
*(module->job_buffer++) = module->hw->DATA.reg;
module->remaining_number -= 1;
if (module->remaining_number == 0) {
if (module->job_status == STATUS_BUSY) {
/* Job is complete. Update status, disable interrupt
* and call callback */
module->job_status = STATUS_OK;
module->hw->INTENCLR.reg = TRNG_INTENCLR_DATARDY;
(module->callback[TRNG_CALLBACK_READ_BUFFER])(module);
}
}
}
/* Clear interrupt flag */
module->hw->INTFLAG.reg = TRNG_INTFLAG_DATARDY;
}
/**
* \brief Read multiple random data from TRNG
*
* As soon as the TRNG is enabled, the module provides a new 32-bits
* random data for every 84 CLK_TRNG_APB clock cycles.
*
* \param[in] module_inst Pointer to the TRNG software instance struct
* \param[in] number Number of random data to get
* \param[out] buffer Buffer to store the random data
*
* \return Status of the job start.
* \retval STATUS_OK The read job was started successfully and is
* in progress
* \retval STATUS_BUSY The TRNG is already busy with another job
*/
enum status_code trng_read_buffer_job(
struct trng_module *const module_inst,
uint32_t *buffer,
uint32_t number)
{
Assert(module_inst);
Assert(number);
Assert(buffer);
if (module_inst->remaining_number != 0 ||
module_inst->job_status == STATUS_BUSY) {
return STATUS_BUSY;
}
module_inst->job_status = STATUS_BUSY;
module_inst->remaining_number = number;
module_inst->job_buffer = buffer;
/* Enable data ready interrupt */
module_inst->hw->INTENSET.reg = TRNG_INTENSET_DATARDY;
return STATUS_OK;
}
/**
* \brief Gets the status of a job
*
* Gets the status of an ongoing or the last job.
*
* \param [in] module_inst Pointer to the TRNG software instance struct
* \param [in] type Type of job to abort
*
* \return Status of the job.
*/
enum status_code trng_get_job_status(
struct trng_module *module_inst,
enum trng_job_type type)
{
/* Sanity check arguments */
Assert(module_inst);
if (type == TRNG_JOB_READ_BUFFER) {
return module_inst->job_status;
} else {
return STATUS_ERR_INVALID_ARG;
}
}
/**
* \brief Aborts an ongoing job
*
* \param [in] module_inst Pointer to the TRNG software instance struct
* \param [in] type Type of job to abort
*/
void trng_abort_job(
struct trng_module *module_inst,
enum trng_job_type type)
{
/* Sanity check arguments */
Assert(module_inst);
if (type == TRNG_JOB_READ_BUFFER) {
/* Disable interrupt */
module_inst->hw->INTENCLR.reg = TRNG_INTENCLR_DATARDY;
/* Mark job as aborted */
module_inst->job_status = STATUS_ABORTED;
module_inst->remaining_number = 0;
}
}
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