1 /* 2 * linux/arch/arm/kernel/time.c 3 * 4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds 5 * Modifications for ARM (C) 1994-2001 Russell King 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This file contains the ARM-specific time handling details: 12 * reading the RTC at bootup, etc... 13 */ 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/interrupt.h> 17 #include <linux/time.h> 18 #include <linux/init.h> 19 #include <linux/sched.h> 20 #include <linux/smp.h> 21 #include <linux/timex.h> 22 #include <linux/errno.h> 23 #include <linux/profile.h> 24 #include <linux/sysdev.h> 25 #include <linux/timer.h> 26 #include <linux/irq.h> 27 28 #include <linux/mc146818rtc.h> 29 30 #include <asm/leds.h> 31 #include <asm/thread_info.h> 32 #include <asm/stacktrace.h> 33 #include <asm/mach/arch.h> 34 #include <asm/mach/time.h> 35 36 /* 37 * Our system timer. 38 */ 39 static struct sys_timer *system_timer; 40 41 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) 42 /* this needs a better home */ 43 DEFINE_SPINLOCK(rtc_lock); 44 45 #ifdef CONFIG_RTC_DRV_CMOS_MODULE 46 EXPORT_SYMBOL(rtc_lock); 47 #endif 48 #endif /* pc-style 'CMOS' RTC support */ 49 50 /* change this if you have some constant time drift */ 51 #define USECS_PER_JIFFY (1000000/HZ) 52 53 #ifdef CONFIG_SMP 54 unsigned long profile_pc(struct pt_regs *regs) 55 { 56 struct stackframe frame; 57 58 if (!in_lock_functions(regs->ARM_pc)) 59 return regs->ARM_pc; 60 61 frame.fp = regs->ARM_fp; 62 frame.sp = regs->ARM_sp; 63 frame.lr = regs->ARM_lr; 64 frame.pc = regs->ARM_pc; 65 do { 66 int ret = unwind_frame(&frame); 67 if (ret < 0) 68 return 0; 69 } while (in_lock_functions(frame.pc)); 70 71 return frame.pc; 72 } 73 EXPORT_SYMBOL(profile_pc); 74 #endif 75 76 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET 77 u32 arch_gettimeoffset(void) 78 { 79 if (system_timer->offset != NULL) 80 return system_timer->offset() * 1000; 81 82 return 0; 83 } 84 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */ 85 86 #ifdef CONFIG_LEDS_TIMER 87 static inline void do_leds(void) 88 { 89 static unsigned int count = HZ/2; 90 91 if (--count == 0) { 92 count = HZ/2; 93 leds_event(led_timer); 94 } 95 } 96 #else 97 #define do_leds() 98 #endif 99 100 101 #ifndef CONFIG_GENERIC_CLOCKEVENTS 102 /* 103 * Kernel system timer support. 104 */ 105 void timer_tick(void) 106 { 107 profile_tick(CPU_PROFILING); 108 do_leds(); 109 write_seqlock(&xtime_lock); 110 do_timer(1); 111 write_sequnlock(&xtime_lock); 112 #ifndef CONFIG_SMP 113 update_process_times(user_mode(get_irq_regs())); 114 #endif 115 } 116 #endif 117 118 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS) 119 static int timer_suspend(struct sys_device *dev, pm_message_t state) 120 { 121 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 122 123 if (timer->suspend != NULL) 124 timer->suspend(); 125 126 return 0; 127 } 128 129 static int timer_resume(struct sys_device *dev) 130 { 131 struct sys_timer *timer = container_of(dev, struct sys_timer, dev); 132 133 if (timer->resume != NULL) 134 timer->resume(); 135 136 return 0; 137 } 138 #else 139 #define timer_suspend NULL 140 #define timer_resume NULL 141 #endif 142 143 static struct sysdev_class timer_sysclass = { 144 .name = "timer", 145 .suspend = timer_suspend, 146 .resume = timer_resume, 147 }; 148 149 static int __init timer_init_sysfs(void) 150 { 151 int ret = sysdev_class_register(&timer_sysclass); 152 if (ret == 0) { 153 system_timer->dev.cls = &timer_sysclass; 154 ret = sysdev_register(&system_timer->dev); 155 } 156 157 return ret; 158 } 159 160 device_initcall(timer_init_sysfs); 161 162 void __init time_init(void) 163 { 164 system_timer = machine_desc->timer; 165 system_timer->init(); 166 } 167 168