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/*
*
* Copyright 2002 Momentum Computer
* Author: mdharm@momenco.com
*
* arch/mips/momentum/ocelot_g/gt_irq.c
* Interrupt routines for gt64240. Currently it only handles timer irq.
*
* 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.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <asm/ptrace.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <asm/gt64240.h>
#include <asm/io.h>
unsigned long bus_clock;
/*
* 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.
*/
#if CURRENTLY_UNUSED
struct tq_struct irq_handlers[MAX_CAUSE_REGS][MAX_CAUSE_REG_WIDTH];
void hook_irq_handler(int int_cause, int bit_num, void *isr_ptr);
/*
* Hooks IRQ handler to the system. When the system is interrupted
* the interrupt service routine is called.
*
* Inputs :
* int_cause - The interrupt cause number. In EVB64120 two parameters
* are declared, INT_CAUSE_MAIN and INT_CAUSE_HIGH.
* bit_num - Indicates which bit number in the cause register
* isr_ptr - Pointer to the interrupt service routine
*/
void hook_irq_handler(int int_cause, int bit_num, void *isr_ptr)
{
irq_handlers[int_cause][bit_num].routine = isr_ptr;
}
/*
* Enables the IRQ on Galileo Chip
*
* Inputs :
* int_cause - The interrupt cause number. In EVB64120 two parameters
* are declared, INT_CAUSE_MAIN and INT_CAUSE_HIGH.
* bit_num - Indicates which bit number in the cause register
*
* Outputs :
* 1 if successful, 0 if failure
*/
int enable_galileo_irq(int int_cause, int bit_num)
{
if (int_cause == INT_CAUSE_MAIN)
SET_REG_BITS(CPU_INTERRUPT_MASK_REGISTER, (1 << bit_num));
else if (int_cause == INT_CAUSE_HIGH)
SET_REG_BITS(CPU_HIGH_INTERRUPT_MASK_REGISTER,
(1 << bit_num));
else
return 0;
return 1;
}
/*
* Disables the IRQ on Galileo Chip
*
* Inputs :
* int_cause - The interrupt cause number. In EVB64120 two parameters
* are declared, INT_CAUSE_MAIN and INT_CAUSE_HIGH.
* bit_num - Indicates which bit number in the cause register
*
* Outputs :
* 1 if successful, 0 if failure
*/
int disable_galileo_irq(int int_cause, int bit_num)
{
if (int_cause == INT_CAUSE_MAIN)
RESET_REG_BITS(CPU_INTERRUPT_MASK_REGISTER,
(1 << bit_num));
else if (int_cause == INT_CAUSE_HIGH)
RESET_REG_BITS(CPU_HIGH_INTERRUPT_MASK_REGISTER,
(1 << bit_num));
else
return 0;
return 1;
}
#endif /* UNUSED */
/*
* Interrupt handler for interrupts coming from the Galileo chip via P0_INT#.
*
* We route the timer interrupt to P0_INT# (IRQ 6), and that's all this
* routine can handle, for now.
*
* In the future, we'll route more interrupts to this pin, and that's why
* we keep this particular structure in the function.
*/
static irqreturn_t gt64240_p0int_irq(int irq, void *dev, struct pt_regs *regs)
{
uint32_t irq_src, irq_src_mask;
int handled;
/* get the low interrupt cause register */
irq_src = MV_READ(LOW_INTERRUPT_CAUSE_REGISTER);
/* get the mask register for this pin */
irq_src_mask = MV_READ(PCI_0INTERRUPT_CAUSE_MASK_REGISTER_LOW);
/* mask off only the interrupts we're interested in */
irq_src = irq_src & irq_src_mask;
handled = IRQ_NONE;
/* Check for timer interrupt */
if (irq_src & 0x00000100) {
handled = IRQ_HANDLED;
irq_src &= ~0x00000100;
/* Clear any pending cause bits */
MV_WRITE(TIMER_COUNTER_0_3_INTERRUPT_CAUSE, 0x0);
/* handle the timer call */
do_timer(regs);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
}
if (irq_src) {
printk(KERN_INFO
"UNKNOWN P0_INT# interrupt received, irq_src=0x%x\n",
irq_src);
}
return handled;
}
/*
* Initializes timer using galileo's built in timer.
*/
/*
* 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 gt64240_time_init(void)
{
static struct irqaction timer;
/* Stop the timer -- we'll use timer #0 */
MV_WRITE(TIMER_COUNTER_0_3_CONTROL, 0x0);
/* Load timer value for 100 Hz */
MV_WRITE(TIMER_COUNTER0, bus_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 = >64240_p0int_irq;
timer.flags = SA_SHIRQ | SA_INTERRUPT;
timer.name = "timer";
timer.dev_id = NULL;
timer.next = NULL;
timer.mask = CPU_MASK_NONE;
irq_desc[6].action = &timer;
enable_irq(6);
/* Clear any pending cause bits */
MV_WRITE(TIMER_COUNTER_0_3_INTERRUPT_CAUSE, 0x0);
/* Enable the interrupt for timer 0 */
MV_WRITE(TIMER_COUNTER_0_3_INTERRUPT_MASK, 0x1);
/* Enable the timer interrupt for GT-64240 pin P0_INT# */
MV_WRITE (PCI_0INTERRUPT_CAUSE_MASK_REGISTER_LOW, 0x100);
/* Configure and start the timer */
MV_WRITE(TIMER_COUNTER_0_3_CONTROL, 0x3);
}
void gt64240_irq_init(void)
{
#if CURRENTLY_UNUSED
int i, j;
/* Reset irq handlers pointers to NULL */
for (i = 0; i < MAX_CAUSE_REGS; i++) {
for (j = 0; j < MAX_CAUSE_REG_WIDTH; j++) {
irq_handlers[i][j].next = NULL;
irq_handlers[i][j].sync = 0;
irq_handlers[i][j].routine = NULL;
irq_handlers[i][j].data = NULL;
}
}
#endif
}
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