/*
 * File      : interrupt.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2009, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2009-01-05     Bernard      first version
 */

#include <rtthread.h>
#include <asm/ppc4xx.h>
#include <asm/processor.h>

/* interrupt nest */
extern volatile rt_uint8_t rt_interrupt_nest;

/* exception and interrupt handler table */
#define MAX_HANDLERS 32
rt_isr_handler_t isr_table[MAX_HANDLERS];

rt_uint32_t rt_interrupt_from_thread, rt_interrupt_to_thread;
rt_uint32_t rt_thread_switch_interrput_flag;

rt_isr_handler_t rt_hw_interrupt_handle(rt_uint32_t vector)
{
	rt_kprintf("Unhandled interrupt %d occured!!!\n", vector);
	return RT_NULL;
}

void uic_irq_ack(unsigned int vec)
{
	mtdcr(uic0sr, UIC_MASK(vec));
}

void  uic_int_handler (unsigned int vec)
{
	rt_interrupt_enter();

    /* Allow external interrupts to the CPU. */
    if (isr_table [vec] != 0)
    {
       (*isr_table[vec])(vec);
    }
    uic_irq_ack(vec);
	
    rt_interrupt_leave();
}

/* handler for UIC interrupt */
void uic_interrupt(rt_uint32_t uic_base, int vec_base)
{
	int vec;
	rt_uint32_t uic_msr;
	rt_uint32_t msr_shift;

	/*
	 * Read masked interrupt status register to determine interrupt source
	 */
	uic_msr = get_dcr(uic_base + UIC_MSR);
	msr_shift = uic_msr;
	vec = vec_base;

	while (msr_shift != 0)
	{
		if (msr_shift & 0x80000000)
			uic_int_handler(vec);

		/*
		 * Shift msr to next position and increment vector
		 */
		msr_shift <<= 1;
		vec++;
	}
}

void rt_hw_interrupt_install(int vector, rt_isr_handler_t new_handler, rt_isr_handler_t *old_handler)
{
    int	intVal;

    if (((int)vector < 0)  || ((int) vector >= MAX_HANDLERS)) 
	{
        return;   /*  out of range  */
	}
   
    /* install the handler in the system interrupt table  */
    intVal = rt_hw_interrupt_disable (); /* lock interrupts to prevent races */

	if (*old_handler != RT_NULL) *old_handler = isr_table[vector];
	if (new_handler != RT_NULL) isr_table[vector] = new_handler;

    rt_hw_interrupt_enable (intVal);
}

void rt_hw_interrupt_mask(int vector)
{
	mtdcr(uic0er, mfdcr(uic0er) & ~UIC_MASK(vector));
}

void rt_hw_interrupt_unmask(int vector)
{
	mtdcr(uic0er, mfdcr(uic0er) | UIC_MASK(vector));
}

void rt_hw_interrupt_init()
{
	int vector;
    rt_uint32_t pit_value;

    pit_value = RT_TICK_PER_SECOND * (100000000 / RT_CPU_FREQ);

    /* enable pit */
	mtspr(SPRN_PIT, pit_value);
	mtspr(SPRN_TCR, 0x4400000);

	/* set default interrupt handler */
    for (vector = 0; vector < MAX_HANDLERS; vector++)
    {
	    isr_table [vector] = (rt_isr_handler_t)rt_hw_interrupt_handle;
    }

	/* initialize interrupt nest, and context in thread sp */
	rt_interrupt_nest = 0;
	rt_interrupt_from_thread = 0;
	rt_interrupt_to_thread = 0;
	rt_thread_switch_interrput_flag = 0;
}

/*@}*/
