| 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/clockchips.h> |
| 12 | #include <linux/clocksource.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/export.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/interrupt.h> |
| 17 | #include <linux/irq.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/of_clk.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(addr: 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(addr: frame.pc)); |
| 57 | |
| 58 | return frame.pc; |
| 59 | } |
| 60 | EXPORT_SYMBOL(profile_pc); |
| 61 | #endif |
| 62 | |
| 63 | static void dummy_clock_access(struct timespec64 *ts) |
| 64 | { |
| 65 | ts->tv_sec = 0; |
| 66 | ts->tv_nsec = 0; |
| 67 | } |
| 68 | |
| 69 | static clock_access_fn __read_persistent_clock = dummy_clock_access; |
| 70 | |
| 71 | void read_persistent_clock64(struct timespec64 *ts) |
| 72 | { |
| 73 | __read_persistent_clock(ts); |
| 74 | } |
| 75 | |
| 76 | int __init register_persistent_clock(clock_access_fn read_persistent) |
| 77 | { |
| 78 | /* Only allow the clockaccess functions to be registered once */ |
| 79 | if (__read_persistent_clock == dummy_clock_access) { |
| 80 | if (read_persistent) |
| 81 | __read_persistent_clock = read_persistent; |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | return -EINVAL; |
| 86 | } |
| 87 | |
| 88 | void __init time_init(void) |
| 89 | { |
| 90 | if (machine_desc->init_time) { |
| 91 | machine_desc->init_time(); |
| 92 | } else { |
| 93 | #ifdef CONFIG_COMMON_CLK |
| 94 | of_clk_init(NULL); |
| 95 | #endif |
| 96 | timer_probe(); |
| 97 | tick_setup_hrtimer_broadcast(); |
| 98 | } |
| 99 | } |
| 100 |