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/syscore_ops.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/sched_clock.h> 33 #include <asm/stacktrace.h> 34 #include <asm/mach/arch.h> 35 #include <asm/mach/time.h> 36 37 /* 38 * Our system timer. 39 */ 40 static struct sys_timer *system_timer; 41 42 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) 43 /* this needs a better home */ 44 DEFINE_SPINLOCK(rtc_lock); 45 46 #ifdef CONFIG_RTC_DRV_CMOS_MODULE 47 EXPORT_SYMBOL(rtc_lock); 48 #endif 49 #endif /* pc-style 'CMOS' RTC support */ 50 51 /* change this if you have some constant time drift */ 52 #define USECS_PER_JIFFY (1000000/HZ) 53 54 #ifdef CONFIG_SMP 55 unsigned long profile_pc(struct pt_regs *regs) 56 { 57 struct stackframe frame; 58 59 if (!in_lock_functions(regs->ARM_pc)) 60 return regs->ARM_pc; 61 62 frame.fp = regs->ARM_fp; 63 frame.sp = regs->ARM_sp; 64 frame.lr = regs->ARM_lr; 65 frame.pc = regs->ARM_pc; 66 do { 67 int ret = unwind_frame(&frame); 68 if (ret < 0) 69 return 0; 70 } while (in_lock_functions(frame.pc)); 71 72 return frame.pc; 73 } 74 EXPORT_SYMBOL(profile_pc); 75 #endif 76 77 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET 78 u32 arch_gettimeoffset(void) 79 { 80 if (system_timer->offset != NULL) 81 return system_timer->offset() * 1000; 82 83 return 0; 84 } 85 #endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */ 86 87 #ifdef CONFIG_LEDS_TIMER 88 static inline void do_leds(void) 89 { 90 static unsigned int count = HZ/2; 91 92 if (--count == 0) { 93 count = HZ/2; 94 leds_event(led_timer); 95 } 96 } 97 #else 98 #define do_leds() 99 #endif 100 101 102 #ifndef CONFIG_GENERIC_CLOCKEVENTS 103 /* 104 * Kernel system timer support. 105 */ 106 void timer_tick(void) 107 { 108 profile_tick(CPU_PROFILING); 109 do_leds(); 110 xtime_update(1); 111 #ifndef CONFIG_SMP 112 update_process_times(user_mode(get_irq_regs())); 113 #endif 114 } 115 #endif 116 117 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS) 118 static int timer_suspend(void) 119 { 120 if (system_timer->suspend) 121 system_timer->suspend(); 122 123 return 0; 124 } 125 126 static void timer_resume(void) 127 { 128 if (system_timer->resume) 129 system_timer->resume(); 130 } 131 #else 132 #define timer_suspend NULL 133 #define timer_resume NULL 134 #endif 135 136 static struct syscore_ops timer_syscore_ops = { 137 .suspend = timer_suspend, 138 .resume = timer_resume, 139 }; 140 141 static int __init timer_init_syscore_ops(void) 142 { 143 register_syscore_ops(&timer_syscore_ops); 144 145 return 0; 146 } 147 148 device_initcall(timer_init_syscore_ops); 149 150 void __init time_init(void) 151 { 152 system_timer = machine_desc->timer; 153 system_timer->init(); 154 #ifdef CONFIG_HAVE_SCHED_CLOCK 155 sched_clock_postinit(); 156 #endif 157 } 158 159