rt-thread/bsp/samd21/sam_d2x_asflib/sam0/drivers/trng/trng.c

/**
 * \file
 *
 * \brief SAM True Random Number Generator (TRNG) Driver
 *
 * Copyright (C) 2014-2015 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.h"

/**
 * \brief Initializes a hardware TRNG module instance.
 *
 * Enables the clock and initializes the TRNG module, based on the given
 * configuration values.
 *
 * \param[in,out] module_inst  Pointer to the software module instance struct
 * \param[in]     hw           Pointer to the TRNG hardware module
 * \param[in]     config       Pointer to the TRNG configuration options struct
 *
 * \return Status of the initialization procedure.
 *
 * \retval STATUS_OK           The module was initialized successfully
 */
enum status_code trng_init(
		struct trng_module *const module_inst,
		Trng *const hw,
		struct trng_config *const config)
{
	/* Sanity check arguments */
	Assert(module_inst);
	Assert(hw);
	Assert(config);

	/* Initialize device instance */
	module_inst->hw = hw;

	/* Turn on the digital interface clock */
	system_apb_clock_set_mask(SYSTEM_CLOCK_APB_APBC, MCLK_APBCMASK_TRNG);

#if TRNG_CALLBACK_MODE == true
	/* Initialize parameters */
	for (uint8_t i = 0; i < TRNG_CALLBACK_N; i++) {
		module_inst->callback[i] = NULL;
	}

	/* Initialize software flags*/
	module_inst->register_callback_mask = 0x00;
	module_inst->enable_callback_mask   = 0x00;
	module_inst->job_buffer             = NULL;
	module_inst->remaining_number       = 0;
	module_inst->job_status             = STATUS_OK;

	/* Register this instance for callbacks*/
	_trng_instance = module_inst;
#endif

	/* Write configuration to module */
	hw->CTRLA.reg = ((uint32_t)config->run_in_standby << TRNG_CTRLA_RUNSTDBY_Pos);

	return STATUS_OK;
}