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/* -*- c -*- */
/*
* Copyright 2007 Free Software Foundation, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "pic.h"
#include "hal_io.h"
#include "memory_map.h"
#define NVECTORS 8
/*
* Our secondary interrupt vector.
*/
irq_handler_t pic_vector[NVECTORS] = {
nop_handler,
nop_handler,
nop_handler,
nop_handler,
nop_handler,
nop_handler,
nop_handler,
nop_handler
};
void
pic_init(void)
{
// uP is level triggered
pic_regs->mask = ~0; // mask all interrupts
pic_regs->edge_enable = PIC_ONETIME_INT | PIC_PHY_INT;
pic_regs->polarity = ~0 & ~PIC_PHY_INT; // rising edge
pic_regs->pending = ~0; // clear all pending ints
}
/*
* This magic gets pic_interrupt_handler wired into the
* system interrupt handler with the appropriate prologue and
* epilogue.
*/
void pic_interrupt_handler() __attribute__ ((interrupt_handler));
void pic_interrupt_handler()
{
// pending and not masked interrupts
int live = pic_regs->pending & ~pic_regs->mask;
// FIXME loop while there are interrupts to service.
// That will reduce our overhead.
// handle the first one set
int i;
int mask;
for (i=0, mask=1; i < NVECTORS; i++, mask <<= 1){
if (mask & live){ // handle this one
// puthex_nl(i);
(*pic_vector[i])(i);
pic_regs->pending = mask; // clear pending interrupt
return;
}
}
}
void
pic_register_handler(unsigned irq, irq_handler_t handler)
{
if (irq >= NVECTORS)
return;
pic_vector[irq] = handler;
pic_regs->mask &= ~IRQ_TO_MASK(irq);
}
void
nop_handler(unsigned irq)
{
// nop
}
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