arch/arm/cpu/armv7/s5p-common/timer.c

   1 /*
   2  * Copyright (C) 2009 Samsung Electronics
   3  * Heungjun Kim <riverful.kim@samsung.com>
   4  * Inki Dae <inki.dae@samsung.com>
   5  * Minkyu Kang <mk7.kang@samsung.com>
   6  *
   7  * See file CREDITS for list of people who contributed to this
   8  * project.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of
  13  * the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23  * MA 02111-1307 USA
  24  */
  25
  26 #include <common.h>
  27 #include <asm/io.h>
  28 #include <asm/arch/pwm.h>
  29 #include <asm/arch/clk.h>
  30 #include <pwm.h>
  31
  32 DECLARE_GLOBAL_DATA_PTR;
  33
  34 /* macro to read the 16 bit timer */
  35 static inline struct s5p_timer *s5p_get_base_timer(void)
  36 {
  37         return (struct s5p_timer *)samsung_get_base_timer();
  38 }
  39
  40 int timer_init(void)
  41 {
  42         /* PWM Timer 4 */
  43         pwm_init(4, MUX_DIV_2, 0);
  44         pwm_config(4, 0, 0);
  45         pwm_enable(4);
  46
  47         return 0;
  48 }
  49
  50 /*
  51  * timer without interrupts
  52  */
  53 void reset_timer(void)
  54 {
  55         reset_timer_masked();
  56 }
  57
  58 unsigned long get_timer(unsigned long base)
  59 {
  60         return get_timer_masked() - base;
  61 }
  62
  63 /* delay x useconds */
  64 void __udelay(unsigned long usec)
  65 {
  66         struct s5p_timer *const timer = s5p_get_base_timer();
  67         unsigned long tmo, tmp, count_value;
  68
  69         count_value = readl(&timer->tcntb4);
  70
  71         if (usec >= 1000) {
  72                 /*
  73                  * if "big" number, spread normalization
  74                  * to seconds
  75                  * 1. start to normalize for usec to ticks per sec
  76                  * 2. find number of "ticks" to wait to achieve target
  77                  * 3. finish normalize.
  78                  */
  79                 tmo = usec / 1000;
  80                 tmo *= (CONFIG_SYS_HZ * count_value / 10);
  81                 tmo /= 1000;
  82         } else {
  83                 /* else small number, don't kill it prior to HZ multiply */
  84                 tmo = usec * CONFIG_SYS_HZ * count_value / 10;
  85                 tmo /= (1000 * 1000);
  86         }
  87
  88         /* get current timestamp */
  89         tmp = get_timer(0);
  90
  91         /* if setting this fordward will roll time stamp */
  92         /* reset "advancing" timestamp to 0, set lastinc value */
  93         /* else, set advancing stamp wake up time */
  94         if ((tmo + tmp + 1) < tmp)
  95                 reset_timer_masked();
  96         else
  97                 tmo += tmp;
  98
  99         /* loop till event */
 100         while (get_timer_masked() < tmo)
 101                 ;       /* nop */
 102 }
 103
 104 void reset_timer_masked(void)
 105 {
 106         struct s5p_timer *const timer = s5p_get_base_timer();
 107
 108         /* reset time */
 109         gd->lastinc = readl(&timer->tcnto4);
 110         gd->tbl = 0;
 111 }
 112
 113 unsigned long get_timer_masked(void)
 114 {
 115         struct s5p_timer *const timer = s5p_get_base_timer();
 116         unsigned long now = readl(&timer->tcnto4);
 117         unsigned long count_value = readl(&timer->tcntb4);
 118
 119         if (gd->lastinc >= now)
 120                 gd->tbl += gd->lastinc - now;
 121         else
 122                 gd->tbl += gd->lastinc + count_value - now;
 123
 124         gd->lastinc = now;
 125
 126         return gd->tbl;
 127 }
 128
 129 /*
 130  * This function is derived from PowerPC code (read timebase as long long).
 131  * On ARM it just returns the timer value.
 132  */
 133 unsigned long long get_ticks(void)
 134 {
 135         return get_timer(0);
 136 }
 137
 138 /*
 139  * This function is derived from PowerPC code (timebase clock frequency).
 140  * On ARM it returns the number of timer ticks per second.
 141  */
 142 unsigned long get_tbclk(void)
 143 {
 144         return CONFIG_SYS_HZ;
 145 }