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/*
* (C) Copyright 2002
* John W. Linville <linville@tuxdriver.com>
*
* Copied and modified from original code by Josh Huber. Original
* copyright notice preserved below.
*
* (C) Copyright 2001
* Josh Huber <huber@mclx.com>, Mission Critical Linux, Inc.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* interrupts.c - just enough support for the decrementer/timer
*/
#include <common.h>
#include <asm/processor.h>
#include <command.h>
#include "i8259.h"
#undef DEBUG
#ifdef DEBUG
#define PRINTF(fmt,args...) printf (fmt ,##args)
#else
#define PRINTF(fmt,args...)
#endif
#define NR_IRQS 16
void irq_alloc_init(void);
long irq_alloc(long wanted);
/****************************************************************************/
unsigned decrementer_count; /* count value for 1e6/HZ microseconds */
struct irq_action {
interrupt_handler_t *handler;
void *arg;
ulong count;
};
static struct irq_action irq_handlers[NR_IRQS];
/****************************************************************************/
static __inline__ unsigned long
get_msr(void)
{
unsigned long msr;
asm volatile("mfmsr %0" : "=r" (msr) :);
return msr;
}
static __inline__ void
set_msr(unsigned long msr)
{
asm volatile("mtmsr %0" : : "r" (msr));
}
static __inline__ unsigned long
get_dec(void)
{
unsigned long val;
asm volatile("mfdec %0" : "=r" (val) :);
return val;
}
static __inline__ void
set_dec(unsigned long val)
{
asm volatile("mtdec %0" : : "r" (val));
}
void
enable_interrupts(void)
{
set_msr (get_msr() | MSR_EE);
}
/* returns flag if MSR_EE was set before */
int
disable_interrupts(void)
{
ulong msr;
msr = get_msr();
set_msr (msr & ~MSR_EE);
return ((msr & MSR_EE) != 0);
}
/****************************************************************************/
int interrupt_init (void)
{
extern void new_reset(void);
extern void new_reset_end(void);
#ifdef DEBUG
puts("interrupt_init: setting decrementer_count\n");
#endif
decrementer_count = get_tbclk() / CFG_HZ;
#ifdef DEBUG
puts("interrupt_init: setting actual decremter\n");
#endif
set_dec (get_tbclk() / CFG_HZ);
#ifdef DEBUG
puts("interrupt_init: clearing external interrupt table\n");
#endif
/* clear external interrupt table here */
memset(irq_handlers, 0, sizeof(irq_handlers));
#ifdef DEBUG
puts("interrupt_init: initializing interrupt controller\n");
#endif
i8259_init();
#ifdef DEBUG
puts("Copying reset trampoline\n");
#endif
/* WARNING: Assmues that the first megabyte is CACHEINHIBIT! */
memcpy((void *)0x100, new_reset, new_reset_end - new_reset);
#ifdef DEBUG
PRINTF("interrupt_init: enabling interrupts (msr = %08x)\n",
get_msr());
#endif
set_msr (get_msr() | MSR_EE);
#ifdef DEBUG
PRINTF("interrupt_init: done. (msr = %08x)\n", get_msr());
#endif
}
/****************************************************************************/
/*
* Handle external interrupts
*/
void
external_interrupt(struct pt_regs *regs)
{
extern int i8259_irq(void);
int irq, unmask = 1;
irq = i8259_irq(); //i8259_get_irq(regs);
// printf("irq = %d, handler at %p ack=%d\n", irq, irq_handlers[irq].handler, *(volatile unsigned char *)0xFEF00000);
i8259_mask_and_ack(irq);
if (irq_handlers[irq].handler != NULL)
(*irq_handlers[irq].handler)(irq_handlers[irq].arg);
else {
PRINTF ("\nBogus External Interrupt IRQ %d\n", irq);
/*
* turn off the bogus interrupt, otherwise it
* might repeat forever
*/
unmask = 0;
}
if (unmask) i8259_unmask_irq(irq);
}
volatile ulong timestamp = 0;
/*
* timer_interrupt - gets called when the decrementer overflows,
* with interrupts disabled.
* Trivial implementation - no need to be really accurate.
*/
void
timer_interrupt(struct pt_regs *regs)
{
set_dec(decrementer_count);
timestamp++;
}
/****************************************************************************/
void
reset_timer(void)
{
timestamp = 0;
}
ulong
get_timer(ulong base)
{
return (timestamp - base);
}
void
set_timer(ulong t)
{
timestamp = t;
}
/****************************************************************************/
/*
* Install and free a interrupt handler.
*/
void
irq_install_handler(int irq, interrupt_handler_t *handler, void *arg)
{
if (irq < 0 || irq >= NR_IRQS) {
PRINTF("irq_install_handler: bad irq number %d\n", irq);
return;
}
if (irq_handlers[irq].handler != NULL)
PRINTF("irq_install_handler: 0x%08lx replacing 0x%08lx\n",
(ulong)handler, (ulong)irq_handlers[irq].handler);
irq_handlers[irq].handler = handler;
irq_handlers[irq].arg = arg;
i8259_unmask_irq(irq);
}
void
irq_free_handler(int irq)
{
if (irq < 0 || irq >= NR_IRQS) {
PRINTF("irq_free_handler: bad irq number %d\n", irq);
return;
}
i8259_mask_irq(irq);
irq_handlers[irq].handler = NULL;
irq_handlers[irq].arg = NULL;
}
/****************************************************************************/
void
do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
{
puts("IRQ related functions are unimplemented currently.\n");
}
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