/**
 * \file
 *
 * \brief SAM System Interrupt Driver
 *
 * Copyright (c) 2012-2018 Microchip Technology Inc. and its subsidiaries.
 *
 * \asf_license_start
 *
 * \page License
 *
 * Subject to your compliance with these terms, you may use Microchip
 * software and any derivatives exclusively with Microchip products.
 * It is your responsibility to comply with third party license terms applicable
 * to your use of third party software (including open source software) that
 * may accompany Microchip software.
 *
 * THIS SOFTWARE IS SUPPLIED BY MICROCHIP "AS IS". NO WARRANTIES,
 * WHETHER EXPRESS, IMPLIED OR STATUTORY, APPLY TO THIS SOFTWARE,
 * INCLUDING ANY IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY,
 * AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL MICROCHIP BE
 * LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE, INCIDENTAL OR CONSEQUENTIAL
 * LOSS, DAMAGE, COST OR EXPENSE OF ANY KIND WHATSOEVER RELATED TO THE
 * SOFTWARE, HOWEVER CAUSED, EVEN IF MICROCHIP HAS BEEN ADVISED OF THE
 * POSSIBILITY OR THE DAMAGES ARE FORESEEABLE.  TO THE FULLEST EXTENT
 * ALLOWED BY LAW, MICROCHIP'S TOTAL LIABILITY ON ALL CLAIMS IN ANY WAY
 * RELATED TO THIS SOFTWARE WILL NOT EXCEED THE AMOUNT OF FEES, IF ANY,
 * THAT YOU HAVE PAID DIRECTLY TO MICROCHIP FOR THIS SOFTWARE.
 *
 * \asf_license_stop
 *
 */
/*
 * Support and FAQ: visit <a href="https://www.microchip.com/support/">Microchip Support</a>
 */
#include "system_interrupt.h"

/**
 * \brief Check if a interrupt line is pending.
 *
 * Checks if the requested interrupt vector is pending.
 *
 * \param[in] vector  Interrupt vector number to check
 *
 * \returns A boolean identifying if the requested interrupt vector is pending.
 *
 * \retval true   Specified interrupt vector is pending
 * \retval false  Specified interrupt vector is not pending
 *
 */
bool system_interrupt_is_pending(
		const enum system_interrupt_vector vector)
{
	bool result;

	if (vector >= _SYSTEM_INTERRUPT_EXTERNAL_VECTOR_START) {
		result = ((NVIC->ISPR[0] & (1 << vector)) != 0);
	} else if (vector == SYSTEM_INTERRUPT_SYSTICK) {
		result = ((SCB->ICSR & SCB_ICSR_PENDSTSET_Msk) != 0);
	} else {
		Assert(false);
		result = false;
	}

	return result;
}

/**
 * \brief Set a interrupt vector as pending.
 *
 * Set the requested interrupt vector as pending (i.e. issues a software
 * interrupt request for the specified vector). The software handler will be
 * handled (if enabled) in a priority order based on vector number and
 * configured priority settings.
 *
 * \param[in] vector  Interrupt vector number which is set as pending
 *
 * \returns Status code identifying if the vector was successfully set as
 *          pending.
 *
 * \retval STATUS_OK           If no error was detected
 * \retval STATUS_INVALID_ARG  If an unsupported interrupt vector number was given
 */
enum status_code system_interrupt_set_pending(
		const enum system_interrupt_vector vector)
{
	enum status_code status = STATUS_OK;

	if (vector >= _SYSTEM_INTERRUPT_EXTERNAL_VECTOR_START) {
		NVIC->ISPR[0] = (1 << vector);
	} else if (vector == SYSTEM_INTERRUPT_NON_MASKABLE) {
		/* Note: Because NMI has highest priority it will be executed
		 * immediately after it has been set pending */
		SCB->ICSR = SCB_ICSR_NMIPENDSET_Msk;
	} else if (vector == SYSTEM_INTERRUPT_SYSTICK) {
		SCB->ICSR = SCB_ICSR_PENDSTSET_Msk;
	} else {
		/* The user want to set something unsupported as pending */
		Assert(false);
		status = STATUS_ERR_INVALID_ARG;
	}

	return status;
}

/**
 * \brief Clear pending interrupt vector.
 *
 * Clear a pending interrupt vector, so the software handler is not executed.
 *
 * \param[in] vector  Interrupt vector number to clear
 *
 * \returns A status code identifying if the interrupt pending state was
 *          successfully cleared.
 *
 * \retval STATUS_OK           If no error was detected
 * \retval STATUS_INVALID_ARG  If an unsupported interrupt vector number was given
 */
enum status_code system_interrupt_clear_pending(
		const enum system_interrupt_vector vector)
{
	enum status_code status = STATUS_OK;

	if (vector >= _SYSTEM_INTERRUPT_EXTERNAL_VECTOR_START) {
		NVIC->ICPR[0] = (1 << vector);
	} else if (vector == SYSTEM_INTERRUPT_NON_MASKABLE) {
		/* Note: Clearing of NMI pending interrupts does not make sense and is
		 * not supported by the device, as it has the highest priority and will
		 * always be executed at the moment it is set */
		return STATUS_ERR_INVALID_ARG;
	} else if (vector == SYSTEM_INTERRUPT_SYSTICK) {
		SCB->ICSR = SCB_ICSR_PENDSTCLR_Msk;
	} else {
		Assert(false);
		status = STATUS_ERR_INVALID_ARG;
	}

	return status;
}

/**
 * \brief Set interrupt vector priority level.
 *
 * Set the priority level of an external interrupt or exception.
 *
 * \param[in] vector          Interrupt vector to change
 * \param[in] priority_level  New vector priority level to set
 *
 * \returns Status code indicating if the priority level of the interrupt was
 *          successfully set.
 *
 * \retval STATUS_OK           If no error was detected
 * \retval STATUS_INVALID_ARG  If an unsupported interrupt vector number was given
 */
enum status_code system_interrupt_set_priority(
		const enum system_interrupt_vector vector,
		const enum system_interrupt_priority_level priority_level)
{
	enum status_code status = STATUS_OK;

	if (vector >= _SYSTEM_INTERRUPT_EXTERNAL_VECTOR_START) {
		uint8_t register_num = vector / 4;
		uint8_t priority_pos = ((vector % 4) * 8) + (8 - __NVIC_PRIO_BITS);

		NVIC->IP[register_num] =
				(NVIC->IP[register_num] & ~(_SYSTEM_INTERRUPT_PRIORITY_MASK << priority_pos)) |
				(priority_level << priority_pos);

	} else if (vector == SYSTEM_INTERRUPT_SYSTICK) {
		SCB->SHP[1] = (priority_level << _SYSTEM_INTERRUPT_SYSTICK_PRI_POS);
	} else {
		Assert(false);
		status = STATUS_ERR_INVALID_ARG;
	}

	return status;
}

/**
 * \brief Get interrupt vector priority level.
 *
 * Retrieves the priority level of the requested external interrupt or exception.
 *
 * \param[in] vector  Interrupt vector of which the priority level will be read
 *
 * \return Currently configured interrupt priority level of the given interrupt
 *         vector.
 */
enum system_interrupt_priority_level system_interrupt_get_priority(
		const enum system_interrupt_vector vector)
{
	uint8_t register_num = vector / 4;
	uint8_t priority_pos = ((vector % 4) * 8) + (8 - __NVIC_PRIO_BITS);

	enum system_interrupt_priority_level priority = SYSTEM_INTERRUPT_PRIORITY_LEVEL_0;

	if (vector >= 0) {
		priority = (enum system_interrupt_priority_level)
				((NVIC->IP[register_num] >> priority_pos) & _SYSTEM_INTERRUPT_PRIORITY_MASK);
	} else if (vector == SYSTEM_INTERRUPT_SYSTICK) {
		priority = (enum system_interrupt_priority_level)
				((SCB->SHP[1] >> _SYSTEM_INTERRUPT_SYSTICK_PRI_POS) & _SYSTEM_INTERRUPT_PRIORITY_MASK);
	}

	return priority;
}