src/soc/samsung/exynos5420/timer.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright 2013 Google Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <arch/io.h>
  17 #include <delay.h>
  18 #include <soc/clk.h>
  19 #include <stdint.h>
  20 #include <timer.h>
  21
  22 static const uint32_t clocks_per_usec = MCT_HZ/1000000;
  23
  24 static uint64_t mct_raw_value(void)
  25 {
  26         uint64_t upper = read32(&exynos_mct->g_cnt_u);
  27         uint64_t lower = read32(&exynos_mct->g_cnt_l);
  28
  29         return (upper << 32) | lower;
  30 }
  31
  32 void init_timer(void)
  33 {
  34         write32(&exynos_mct->g_tcon, read32(&exynos_mct->g_tcon) | (0x1 << 8));
  35 }
  36
  37 void timer_monotonic_get(struct mono_time *mt)
  38 {
  39         /* We don't have to call mct_start() here
  40          * because it was already called in the bootblock
  41          */
  42
  43         mono_time_set_usecs(mt, mct_raw_value() / clocks_per_usec);
  44 }