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/*
* 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.
*
* Galileo Technology chip interrupt handler
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <asm/irq_regs.h>
#include <asm/ptrace.h>
#include <asm/gt64120.h>
/*
* These are interrupt handlers for the GT on-chip interrupts. They all come
* in to the MIPS on a single interrupt line, and have to be handled and ack'ed
* differently than other MIPS interrupts.
*/
static irqreturn_t gt64120_irq(int irq, void *dev_id)
{
unsigned int irq_src, int_high_src, irq_src_mask, int_high_src_mask;
int handled = 0;
irq_src = GT_READ(GT_INTRCAUSE_OFS);
irq_src_mask = GT_READ(GT_INTRMASK_OFS);
int_high_src = GT_READ(GT_HINTRCAUSE_OFS);
int_high_src_mask = GT_READ(GT_HINTRMASK_OFS);
irq_src = irq_src & irq_src_mask;
int_high_src = int_high_src & int_high_src_mask;
if (irq_src & 0x00000800) { /* Check for timer interrupt */
handled = 1;
irq_src &= ~0x00000800;
do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(get_irq_regs()));
#endif
}
GT_WRITE(GT_INTRCAUSE_OFS, 0);
GT_WRITE(GT_HINTRCAUSE_OFS, 0);
return IRQ_HANDLED;
}
/*
* Initializes timer using galileo's built in timer.
*/
#ifdef CONFIG_SYSCLK_100
#define Sys_clock (100 * 1000000) // 100 MHz
#endif
#ifdef CONFIG_SYSCLK_83
#define Sys_clock (83.333 * 1000000) // 83.333 MHz
#endif
#ifdef CONFIG_SYSCLK_75
#define Sys_clock (75 * 1000000) // 75 MHz
#endif
/*
* This will ignore the standard MIPS timer interrupt handler that is passed in
* as *irq (=irq0 in ../kernel/time.c). We will do our own timer interrupt
* handling.
*/
void gt64120_time_init(void)
{
static struct irqaction timer;
/* Disable timer first */
GT_WRITE(GT_TC_CONTROL_OFS, 0);
/* Load timer value for 100 Hz */
GT_WRITE(GT_TC3_OFS, Sys_clock / 100);
/*
* Create the IRQ structure entry for the timer. Since we're too early
* in the boot process to use the "request_irq()" call, we'll hard-code
* the values to the correct interrupt line.
*/
timer.handler = gt64120_irq;
timer.flags = IRQF_SHARED | IRQF_DISABLED;
timer.name = "timer";
timer.dev_id = NULL;
timer.next = NULL;
timer.mask = CPU_MASK_NONE;
irq_desc[GT_TIMER].action = &timer;
enable_irq(GT_TIMER);
/* Enable timer ints */
GT_WRITE(GT_TC_CONTROL_OFS, 0xc0);
/* clear Cause register first */
GT_WRITE(GT_INTRCAUSE_OFS, 0x0);
/* Unmask timer int */
GT_WRITE(GT_INTRMASK_OFS, 0x800);
/* Clear High int register */
GT_WRITE(GT_HINTRCAUSE_OFS, 0x0);
/* Mask All interrupts at High cause interrupt */
GT_WRITE(GT_HINTRMASK_OFS, 0x0);
}
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