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 11#include <asm/irq.h> 12 13#include <asm/hardware/dec21285.h> 14#include <asm/mach/time.h> 15 16#include "common.h" 17 18/* 19 * Footbridge timer 1 support. 20 */ 21static unsigned long timer1_latch; 22 23static unsigned long timer1_gettimeoffset (void) 24{ 25 unsigned long value = timer1_latch - *CSR_TIMER1_VALUE; 26 27 return ((tick_nsec / 1000) * value) / timer1_latch; 28} 29 30static irqreturn_t 31timer1_interrupt(int irq, void *dev_id) 32{ 33 write_seqlock(&xtime_lock); 34 35 *CSR_TIMER1_CLR = 0; 36 37 timer_tick(); 38 39 write_sequnlock(&xtime_lock); 40 41 return IRQ_HANDLED; 42} 43 44static struct irqaction footbridge_timer_irq = { 45 .name = "Timer1 timer tick", 46 .handler = timer1_interrupt, 47 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, 48}; 49 50/* 51 * Set up timer interrupt. 52 */ 53static void __init footbridge_timer_init(void) 54{ 55 timer1_latch = (mem_fclk_21285 + 8 * HZ) / (16 * HZ); 56 57 *CSR_TIMER1_CLR = 0; 58 *CSR_TIMER1_LOAD = timer1_latch; 59 *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV16; 60 61 setup_irq(IRQ_TIMER1, &footbridge_timer_irq); 62 63 isa_rtc_init(); 64} 65 66struct sys_timer footbridge_timer = { 67 .init = footbridge_timer_init, 68 .offset = timer1_gettimeoffset, 69}; 70