xref: /openbmc/linux/arch/arm64/kernel/time.c (revision 715f23b6)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Based on arch/arm/kernel/time.c
4  *
5  * Copyright (C) 1991, 1992, 1995  Linus Torvalds
6  * Modifications for ARM (C) 1994-2001 Russell King
7  * Copyright (C) 2012 ARM Ltd.
8  */
9 
10 #include <linux/clockchips.h>
11 #include <linux/export.h>
12 #include <linux/kernel.h>
13 #include <linux/interrupt.h>
14 #include <linux/time.h>
15 #include <linux/init.h>
16 #include <linux/sched.h>
17 #include <linux/smp.h>
18 #include <linux/timex.h>
19 #include <linux/errno.h>
20 #include <linux/profile.h>
21 #include <linux/syscore_ops.h>
22 #include <linux/timer.h>
23 #include <linux/irq.h>
24 #include <linux/delay.h>
25 #include <linux/clocksource.h>
26 #include <linux/clk-provider.h>
27 #include <linux/acpi.h>
28 
29 #include <clocksource/arm_arch_timer.h>
30 
31 #include <asm/thread_info.h>
32 #include <asm/stacktrace.h>
33 #include <asm/paravirt.h>
34 
35 unsigned long profile_pc(struct pt_regs *regs)
36 {
37 	struct stackframe frame;
38 
39 	if (!in_lock_functions(regs->pc))
40 		return regs->pc;
41 
42 	start_backtrace(&frame, regs->regs[29], regs->pc);
43 
44 	do {
45 		int ret = unwind_frame(NULL, &frame);
46 		if (ret < 0)
47 			return 0;
48 	} while (in_lock_functions(frame.pc));
49 
50 	return frame.pc;
51 }
52 EXPORT_SYMBOL(profile_pc);
53 
54 void __init time_init(void)
55 {
56 	u32 arch_timer_rate;
57 
58 	of_clk_init(NULL);
59 	timer_probe();
60 
61 	tick_setup_hrtimer_broadcast();
62 
63 	arch_timer_rate = arch_timer_get_rate();
64 	if (!arch_timer_rate)
65 		panic("Unable to initialise architected timer.\n");
66 
67 	/* Calibrate the delay loop directly */
68 	lpj_fine = arch_timer_rate / HZ;
69 
70 	pv_time_init();
71 }
72