2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License as published by the
4 * Free Software Foundation; either version 2 of the License, or (at your
5 * option) any later version.
7 * Galileo Technology chip interrupt handler
9 #include <linux/interrupt.h>
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/kernel_stat.h>
13 #include <asm/ptrace.h>
14 #include <asm/gt64120.h>
17 * These are interrupt handlers for the GT on-chip interrupts. They all come
18 * in to the MIPS on a single interrupt line, and have to be handled and ack'ed
19 * differently than other MIPS interrupts.
22 static void gt64120_irq(int irq
, void *dev_id
, struct pt_regs
*regs
)
24 unsigned int irq_src
, int_high_src
, irq_src_mask
, int_high_src_mask
;
27 irq_src
= GT_READ(GT_INTRCAUSE_OFS
);
28 irq_src_mask
= GT_READ(GT_INTRMASK_OFS
);
29 int_high_src
= GT_READ(GT_HINTRCAUSE_OFS
);
30 int_high_src_mask
= GT_READ(GT_HINTRMASK_OFS
);
31 irq_src
= irq_src
& irq_src_mask
;
32 int_high_src
= int_high_src
& int_high_src_mask
;
34 if (irq_src
& 0x00000800) { /* Check for timer interrupt */
36 irq_src
&= ~0x00000800;
39 update_process_times(user_mode(regs
));
43 GT_WRITE(GT_INTRCAUSE_OFS
, 0);
44 GT_WRITE(GT_HINTRCAUSE_OFS
, 0);
48 * Initializes timer using galileo's built in timer.
50 #ifdef CONFIG_SYSCLK_100
51 #define Sys_clock (100 * 1000000) // 100 MHz
53 #ifdef CONFIG_SYSCLK_83
54 #define Sys_clock (83.333 * 1000000) // 83.333 MHz
56 #ifdef CONFIG_SYSCLK_75
57 #define Sys_clock (75 * 1000000) // 75 MHz
61 * This will ignore the standard MIPS timer interrupt handler that is passed in
62 * as *irq (=irq0 in ../kernel/time.c). We will do our own timer interrupt
65 void gt64120_time_init(void)
67 static struct irqaction timer
;
69 /* Disable timer first */
70 GT_WRITE(GT_TC_CONTROL_OFS
, 0);
71 /* Load timer value for 100 Hz */
72 GT_WRITE(GT_TC3_OFS
, Sys_clock
/ 100);
75 * Create the IRQ structure entry for the timer. Since we're too early
76 * in the boot process to use the "request_irq()" call, we'll hard-code
77 * the values to the correct interrupt line.
79 timer
.handler
= gt64120_irq
;
80 timer
.flags
= SA_SHIRQ
| SA_INTERRUPT
;
84 timer
.mask
= CPU_MASK_NONE
;
85 irq_desc
[GT_TIMER
].action
= &timer
;
89 /* Enable timer ints */
90 GT_WRITE(GT_TC_CONTROL_OFS
, 0xc0);
91 /* clear Cause register first */
92 GT_WRITE(GT_INTRCAUSE_OFS
, 0x0);
93 /* Unmask timer int */
94 GT_WRITE(GT_INTRMASK_OFS
, 0x800);
95 /* Clear High int register */
96 GT_WRITE(GT_HINTRCAUSE_OFS
, 0x0);
97 /* Mask All interrupts at High cause interrupt */
98 GT_WRITE(GT_HINTRMASK_OFS
, 0x0);