src/soc/broadcom/cygnus/timer.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright 2015 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/addressmap.h>
  19 #include <timer.h>
  20
  21 #define TIMER_GLB_TIM_CTRL_PRESC_MASK   0x0000FF00
  22 #define TIMER_GLB_TIM_CTRL_TIM_EN       0x00000001
  23 #define TIMER_GLB_TIM_CTRL_PRESC        0x0
  24 /*
  25  * arm clk is 1GHz, periph_clk=arm_clk/2, tick per usec.
  26  * arm clk is set by the bootrom. See util/broadcom/unauth.cfg for details.
  27  */
  28 #define PERIPH_CLOCK                    500
  29 #define CLOCKS_PER_USEC (PERIPH_CLOCK / \
  30         (((TIMER_GLB_TIM_CTRL_PRESC & TIMER_GLB_TIM_CTRL_PRESC_MASK) >> 8) + 1))
  31
  32 struct cygnus_timer {
  33         u32 gtim_glob_low;
  34         u32 gtim_glob_hi;
  35         u32 gtim_glob_ctrl;
  36 };
  37
  38 static struct cygnus_timer * const timer_ptr =
  39                 (void *)IPROC_PERIPH_GLB_TIM_REG_BASE;
  40
  41 static inline uint64_t timer_raw_value(void)
  42 {
  43         uint64_t cur_tick;
  44         uint32_t count_h;
  45         uint32_t count_l;
  46
  47         do {
  48                 count_h = read32(&timer_ptr->gtim_glob_hi);
  49                 count_l = read32(&timer_ptr->gtim_glob_low);
  50                 cur_tick = read32(&timer_ptr->gtim_glob_hi);
  51         } while (cur_tick != count_h);
  52
  53         return (cur_tick << 32) + count_l;
  54 }
  55
  56 void timer_monotonic_get(struct mono_time *mt)
  57 {
  58         mono_time_set_usecs(mt, timer_raw_value() / CLOCKS_PER_USEC);
  59 }
  60
  61 void init_timer(void)
  62 {
  63         write32(&timer_ptr->gtim_glob_ctrl, TIMER_GLB_TIM_CTRL_PRESC);
  64         write32(&timer_ptr->gtim_glob_low, 0);
  65         write32(&timer_ptr->gtim_glob_hi, 0);
  66         write32(&timer_ptr->gtim_glob_ctrl, TIMER_GLB_TIM_CTRL_TIM_EN);
  67 }