/* arcv2_irq_unit.c - ARCv2 Interrupt Unit device driver */

/*
 * Copyright (c) 2014 Wind River Systems, Inc.
 *
 * 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) Neither the name of Wind River Systems nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS 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.
 */

/*
 * DESCRIPTION
 * The ARCv2 interrupt unit has 16 allocated exceptions associated with
 * vectors 0 to 15 and 240 interrupts associated with vectors 16 to 255.
 * The interrupt unit is optional in the ARCv2-based processors. When
 * building a processor, you can configure the processor to include an
 * interrupt unit. The ARCv2 interrupt unit is highly programmable.
 */

#include <nanokernel.h>
#include <arch/cpu.h>
#include <board.h>

/*
 * _arc_v2_irq_unit_init - initialize the interrupt unit device driver
 *
 * Initializes the interrupt unit device driver and the device
 * itself.
 *
 * Interrupts are still locked at this point, so there is no need to protect
 * the window between a write to IRQ_SELECT and subsequent writes to the
 * selected IRQ's registers.
 *
 * RETURNS: N/A
 */

void _arc_v2_irq_unit_init(void)
{
	int irq; /* the interrupt index */

	for (irq = 16; irq < 256; irq++) {
		_arc_v2_aux_reg_write(_ARC_V2_IRQ_SELECT, irq);
		_arc_v2_aux_reg_write(_ARC_V2_IRQ_PRIORITY, 1);
		_arc_v2_aux_reg_write(_ARC_V2_IRQ_ENABLE, _ARC_V2_INT_DISABLE);
		_arc_v2_aux_reg_write(_ARC_V2_IRQ_TRIGGER, _ARC_V2_INT_LEVEL);
	}
}

/*
 * _arc_v2_irq_unit_int_eoi - send EOI signal to interrupt unit
 *
 * This routine sends an EOI (End Of Interrupt) signal to the interrupt unit
 * to clear a pulse-triggered interrupt.
 *
 * Interrupts must be locked or the ISR operating at P0 when invoking this
 * function.
 *
 * RETURNS: N/A
 */

void _arc_v2_irq_unit_int_eoi(int irq)
{
	_arc_v2_aux_reg_write(_ARC_V2_IRQ_SELECT, irq);
	_arc_v2_aux_reg_write(_ARC_V2_IRQ_PULSE_CANCEL, 1);
}

/*
 * _arc_v2_irq_unit_int_trigger_set - sets an IRQ line to level/pulse trigger
 *
 * Sets the IRQ line <irq> to trigger an interrupt based on the level or the
 * edge of the signal. Valid values for <trigger> are _ARC_V2_INT_LEVEL and
 * _ARC_V2_INT_PULSE.
 *
 * RETURNS: N/A
 */

void _arc_v2_irq_unit_trigger_set(int irq, unsigned int trigger)
{
	_arc_v2_aux_reg_write(_ARC_V2_IRQ_SELECT, irq);
	_arc_v2_aux_reg_write(_ARC_V2_IRQ_TRIGGER, trigger);
}