payloads/libpayload/drivers/timer/generic.c

   1 /*
   2  *
   3  * Copyright 2016 Google Inc.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * Alternatively, this software may be distributed under the terms of the
  17  * GNU General Public License ("GPL") version 2 as published by the Free
  18  * Software Foundation.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <assert.h>
  34 #include <libpayload.h>
  35
  36 uint64_t timer_hz(void)
  37 {
  38         return CONFIG_LP_TIMER_GENERIC_HZ;
  39 }
  40
  41 uint64_t timer_raw_value(void)
  42 {
  43         uint64_t cur_tick;
  44         uint32_t count_h;
  45         uint32_t count_l;
  46
  47         if (!CONFIG_LP_TIMER_GENERIC_HIGH_REG)
  48                 return readl(phys_to_virt(CONFIG_LP_TIMER_GENERIC_REG));
  49
  50         do {
  51                 count_h = readl(phys_to_virt(CONFIG_LP_TIMER_GENERIC_HIGH_REG));
  52                 count_l = readl(phys_to_virt(CONFIG_LP_TIMER_GENERIC_REG));
  53                 cur_tick = readl(phys_to_virt(CONFIG_LP_TIMER_GENERIC_HIGH_REG));
  54         } while (cur_tick != count_h);
  55
  56         return (cur_tick << 32) + count_l;
  57 }