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(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 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
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