arch/arm/mach-shmobile/timer.c

   1 /*
   2  * SH-Mobile Timer
   3  *
   4  * Copyright (C) 2010  Magnus Damm
   5  * Copyright (C) 2002 - 2009  Paul Mundt
   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 as published by
   9  * the Free Software Foundation; version 2 of the License.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21 #include <linux/platform_device.h>
  22 #include <linux/clocksource.h>
  23 #include <linux/delay.h>
  24
  25 void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz,
  26                                  unsigned int mult, unsigned int div)
  27 {
  28         /* calculate a worst-case loops-per-jiffy value
  29          * based on maximum cpu core mhz setting and the
  30          * __delay() implementation in arch/arm/lib/delay.S
  31          *
  32          * this will result in a longer delay than expected
  33          * when the cpu core runs on lower frequencies.
  34          */
  35
  36         unsigned int value = (1000000 * mult) / (HZ * div);
  37
  38         if (!preset_lpj)
  39                 preset_lpj = max_cpu_core_mhz * value;
  40 }
  41
  42 static void __init shmobile_late_time_init(void)
  43 {
  44         /*
  45          * Make sure all compiled-in early timers register themselves.
  46          *
  47          * Run probe() for two "earlytimer" devices, these will be the
  48          * clockevents and clocksource devices respectively. In the event
  49          * that only a clockevents device is available, we -ENODEV on the
  50          * clocksource and the jiffies clocksource is used transparently
  51          * instead. No error handling is necessary here.
  52          */
  53         early_platform_driver_register_all("earlytimer");
  54         early_platform_driver_probe("earlytimer", 2, 0);
  55 }
  56
  57 void __init shmobile_earlytimer_init(void)
  58 {
  59         late_time_init = shmobile_late_time_init;
  60 }
  61