payloads/libpayload/drivers/timer/img_pistachio.c

   1 /*
   2  * This file is part of the libpayload project.
   3  *
   4  * Copyright (C) 2014 Imagination Technologies
   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 <libpayload.h>
  17 #include <arch/cpu.h>
  18
  19 uint64_t timer_hz(void)
  20 {
  21         return lib_sysinfo.cpu_khz * 1000;
  22 }
  23
  24 uint64_t timer_raw_value(void)
  25 {
  26         static uint64_t total_ticks = 0;
  27         uint8_t overflow = 0;
  28         uint32_t current_ticks = read_c0_count() * 2;
  29
  30         /* It assumes only one overflow happened since the last call */
  31         if (current_ticks <= (uint32_t)total_ticks)
  32                 overflow = 1;
  33         /* The least significant part(32 bits) of total_ticks will always
  34          * become equal to current ticks */
  35         total_ticks = (((total_ticks  >> 32) + overflow) << 32) +
  36                                 current_ticks;
  37         return total_ticks;
  38 }