arch/arm/kernel/arch_timer.c

   1 /*
   2  *  linux/arch/arm/kernel/arch_timer.c
   3  *
   4  *  Copyright (C) 2011 ARM Ltd.
   5  *  All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/types.h>
  13 #include <linux/errno.h>
  14
  15 #include <asm/delay.h>
  16 #include <asm/sched_clock.h>
  17
  18 #include <clocksource/arm_arch_timer.h>
  19
  20 static unsigned long arch_timer_read_counter_long(void)
  21 {
  22         return arch_timer_read_counter();
  23 }
  24
  25 static u32 arch_timer_read_counter_u32(void)
  26 {
  27         return arch_timer_read_counter();
  28 }
  29
  30 static struct delay_timer arch_delay_timer;
  31
  32 static void __init arch_timer_delay_timer_register(void)
  33 {
  34         /* Use the architected timer for the delay loop. */
  35         arch_delay_timer.read_current_timer = arch_timer_read_counter_long;
  36         arch_delay_timer.freq = arch_timer_get_rate();
  37         register_current_timer_delay(&arch_delay_timer);
  38 }
  39
  40 int __init arch_timer_of_register(void)
  41 {
  42         int ret;
  43
  44         ret = arch_timer_init();
  45         if (ret)
  46                 return ret;
  47
  48         arch_timer_delay_timer_register();
  49
  50         return 0;
  51 }
  52
  53 int __init arch_timer_sched_clock_init(void)
  54 {
  55         if (arch_timer_get_rate() == 0)
  56                 return -ENXIO;
  57
  58         setup_sched_clock(arch_timer_read_counter_u32,
  59                           32, arch_timer_get_rate());
  60         return 0;
  61 }