LXR linux/arch/arm64/kernel/time.c

   1/*
   2 * Based on arch/arm/kernel/time.c
   3 *
   4 * Copyright (C) 1991, 1992, 1995  Linus Torvalds
   5 * Modifications for ARM (C) 1994-2001 Russell King
   6 * Copyright (C) 2012 ARM Ltd.
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21#include <linux/clockchips.h>
  22#include <linux/export.h>
  23#include <linux/kernel.h>
  24#include <linux/interrupt.h>
  25#include <linux/time.h>
  26#include <linux/init.h>
  27#include <linux/sched.h>
  28#include <linux/smp.h>
  29#include <linux/timex.h>
  30#include <linux/errno.h>
  31#include <linux/profile.h>
  32#include <linux/syscore_ops.h>
  33#include <linux/timer.h>
  34#include <linux/irq.h>
  35#include <linux/delay.h>
  36#include <linux/clocksource.h>
  37#include <linux/clk-provider.h>
  38#include <linux/acpi.h>
  39
  40#include <clocksource/arm_arch_timer.h>
  41
  42#include <asm/thread_info.h>
  43#include <asm/stacktrace.h>
  44
  45unsigned long profile_pc(struct pt_regs *regs)
  46{
  47        struct stackframe frame;
  48
  49        if (!in_lock_functions(regs->pc))
  50                return regs->pc;
  51
  52        frame.fp = regs->regs[29];
  53        frame.sp = regs->sp;
  54        frame.pc = regs->pc;
  55#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  56        frame.graph = -1; /* no task info */
  57#endif
  58        do {
  59                int ret = unwind_frame(NULL, &frame);
  60                if (ret < 0)
  61                        return 0;
  62        } while (in_lock_functions(frame.pc));
  63
  64        return frame.pc;
  65}
  66EXPORT_SYMBOL(profile_pc);
  67
  68void __init time_init(void)
  69{
  70        u32 arch_timer_rate;
  71
  72        of_clk_init(NULL);
  73        clocksource_probe();
  74
  75        tick_setup_hrtimer_broadcast();
  76
  77        arch_timer_rate = arch_timer_get_rate();
  78        if (!arch_timer_rate)
  79                panic("Unable to initialise architected timer.\n");
  80
  81        /* Calibrate the delay loop directly */
  82        lpj_fine = arch_timer_rate / HZ;
  83}
  84