1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/arch/arm/kernel/time.c 4 * 5 * Copyright (C) 1991, 1992, 1995 Linus Torvalds 6 * Modifications for ARM (C) 1994-2001 Russell King 7 * 8 * This file contains the ARM-specific time handling details: 9 * reading the RTC at bootup, etc... 10 */ 11 #include <linux/clk-provider.h> 12 #include <linux/clockchips.h> 13 #include <linux/clocksource.h> 14 #include <linux/errno.h> 15 #include <linux/export.h> 16 #include <linux/init.h> 17 #include <linux/interrupt.h> 18 #include <linux/irq.h> 19 #include <linux/kernel.h> 20 #include <linux/profile.h> 21 #include <linux/sched.h> 22 #include <linux/sched_clock.h> 23 #include <linux/smp.h> 24 #include <linux/time.h> 25 #include <linux/timex.h> 26 #include <linux/timer.h> 27 28 #include <asm/mach/arch.h> 29 #include <asm/mach/time.h> 30 #include <asm/stacktrace.h> 31 #include <asm/thread_info.h> 32 33 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \ 34 defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE) 35 /* this needs a better home */ 36 DEFINE_SPINLOCK(rtc_lock); 37 EXPORT_SYMBOL(rtc_lock); 38 #endif /* pc-style 'CMOS' RTC support */ 39 40 /* change this if you have some constant time drift */ 41 #define USECS_PER_JIFFY (1000000/HZ) 42 43 #ifdef CONFIG_SMP 44 unsigned long profile_pc(struct pt_regs *regs) 45 { 46 struct stackframe frame; 47 48 if (!in_lock_functions(regs->ARM_pc)) 49 return regs->ARM_pc; 50 51 arm_get_current_stackframe(regs, &frame); 52 do { 53 int ret = unwind_frame(&frame); 54 if (ret < 0) 55 return 0; 56 } while (in_lock_functions(frame.pc)); 57 58 return frame.pc; 59 } 60 EXPORT_SYMBOL(profile_pc); 61 #endif 62 63 #ifndef CONFIG_GENERIC_CLOCKEVENTS 64 /* 65 * Kernel system timer support. 66 */ 67 void timer_tick(void) 68 { 69 profile_tick(CPU_PROFILING); 70 xtime_update(1); 71 #ifndef CONFIG_SMP 72 update_process_times(user_mode(get_irq_regs())); 73 #endif 74 } 75 #endif 76 77 static void dummy_clock_access(struct timespec64 *ts) 78 { 79 ts->tv_sec = 0; 80 ts->tv_nsec = 0; 81 } 82 83 static clock_access_fn __read_persistent_clock = dummy_clock_access; 84 85 void read_persistent_clock64(struct timespec64 *ts) 86 { 87 __read_persistent_clock(ts); 88 } 89 90 int __init register_persistent_clock(clock_access_fn read_persistent) 91 { 92 /* Only allow the clockaccess functions to be registered once */ 93 if (__read_persistent_clock == dummy_clock_access) { 94 if (read_persistent) 95 __read_persistent_clock = read_persistent; 96 return 0; 97 } 98 99 return -EINVAL; 100 } 101 102 void __init time_init(void) 103 { 104 if (machine_desc->init_time) { 105 machine_desc->init_time(); 106 } else { 107 #ifdef CONFIG_COMMON_CLK 108 of_clk_init(NULL); 109 #endif 110 timer_probe(); 111 tick_setup_hrtimer_broadcast(); 112 } 113 } 114