arch/arm64/kernel/time.c

   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
  34 unsigned long profile_pc(struct pt_regs *regs)
  35 {
  36         struct stackframe frame;
  37
  38         if (!in_lock_functions(regs->pc))
  39                 return regs->pc;
  40
  41         frame.fp = regs->regs[29];
  42         frame.pc = regs->pc;
  43 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  44         frame.graph = 0;
  45 #endif
  46         do {
  47                 int ret = unwind_frame(NULL, &frame);
  48                 if (ret < 0)
  49                         return 0;
  50         } while (in_lock_functions(frame.pc));
  51
  52         return frame.pc;
  53 }
  54 EXPORT_SYMBOL(profile_pc);
  55
  56 void __init time_init(void)
  57 {
  58         u32 arch_timer_rate;
  59
  60         of_clk_init(NULL);
  61         timer_probe();
  62
  63         tick_setup_hrtimer_broadcast();
  64
  65         arch_timer_rate = arch_timer_get_rate();
  66         if (!arch_timer_rate)
  67                 panic("Unable to initialise architected timer.\n");
  68
  69         /* Calibrate the delay loop directly */
  70         lpj_fine = arch_timer_rate / HZ;
  71 }