1/* 2 * linux/arch/arm/mach-footbridge/dc21285-timer.c 3 * 4 * Copyright (C) 1998 Russell King. 5 * Copyright (C) 1998 Phil Blundell 6 */ 7#include <linux/init.h> 8#include <linux/interrupt.h> 9#include <linux/irq.h> 10#include <linux/spinlock.h> 11 12#include <asm/irq.h> 13 14#include <asm/hardware/dec21285.h> 15#include <asm/mach/time.h> 16 17#include "common.h" 18 19/* 20 * Footbridge timer 1 support. 21 */ 22static unsigned long timer1_latch; 23 24static unsigned long timer1_gettimeoffset (void) 25{ 26 unsigned long value = timer1_latch - *CSR_TIMER1_VALUE; 27 28 return ((tick_nsec / 1000) * value) / timer1_latch; 29} 30 31static irqreturn_t 32timer1_interrupt(int irq, void *dev_id) 33{ 34 *CSR_TIMER1_CLR = 0; 35 36 timer_tick(); 37 38 return IRQ_HANDLED; 39} 40 41static struct irqaction footbridge_timer_irq = { 42 .name = "Timer1 timer tick", 43 .handler = timer1_interrupt, 44 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, 45}; 46 47/* 48 * Set up timer interrupt. 49 */ 50static void __init footbridge_timer_init(void) 51{ 52 timer1_latch = (mem_fclk_21285 + 8 * HZ) / (16 * HZ); 53 54 *CSR_TIMER1_CLR = 0; 55 *CSR_TIMER1_LOAD = timer1_latch; 56 *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV16; 57 58 setup_irq(IRQ_TIMER1, &footbridge_timer_irq); 59} 60 61struct sys_timer footbridge_timer = { 62 .init = footbridge_timer_init, 63 .offset = timer1_gettimeoffset, 64}; 65