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 unsigned long get_current_tick(void); 35 36 /* macro to read the 16 bit timer */ 37 static inline struct s5p_timer *s5p_get_base_timer(void) 38 { 39 return (struct s5p_timer *)samsung_get_base_timer(); 40 } 41 42 /** 43 * Read the countdown timer. 44 * 45 * This operates at 1MHz and counts downwards. It will wrap about every 46 * hour (2^32 microseconds). 47 * 48 * @return current value of timer 49 */ 50 static unsigned long timer_get_us_down(void) 51 { 52 struct s5p_timer *const timer = s5p_get_base_timer(); 53 54 return readl(&timer->tcnto4); 55 } 56 57 int timer_init(void) 58 { 59 /* PWM Timer 4 */ 60 pwm_init(4, MUX_DIV_4, 0); 61 pwm_config(4, 0, 0); 62 pwm_enable(4); 63 64 /* Use this as the current monotonic time in us */ 65 gd->arch.timer_reset_value = 0; 66 67 /* Use this as the last timer value we saw */ 68 gd->arch.lastinc = timer_get_us_down(); 69 reset_timer_masked(); 70 71 return 0; 72 } 73 74 /* 75 * timer without interrupts 76 */ 77 unsigned long get_timer(unsigned long base) 78 { 79 ulong now = timer_get_us_down(); 80 81 /* 82 * Increment the time by the amount elapsed since the last read. 83 * The timer may have wrapped around, but it makes no difference to 84 * our arithmetic here. 85 */ 86 gd->arch.timer_reset_value += gd->arch.lastinc - now; 87 gd->arch.lastinc = now; 88 89 /* Divide by 1000 to convert from us to ms */ 90 return gd->arch.timer_reset_value / 1000 - base; 91 } 92 93 /* delay x useconds */ 94 void __udelay(unsigned long usec) 95 { 96 unsigned long count_value; 97 98 count_value = timer_get_us_down(); 99 while ((int)(count_value - timer_get_us_down()) < (int)usec) 100 ; 101 } 102 103 void reset_timer_masked(void) 104 { 105 struct s5p_timer *const timer = s5p_get_base_timer(); 106 107 /* reset time */ 108 gd->arch.lastinc = readl(&timer->tcnto4); 109 gd->arch.tbl = 0; 110 } 111 112 /* 113 * This function is derived from PowerPC code (read timebase as long long). 114 * On ARM it just returns the timer value. 115 */ 116 unsigned long long get_ticks(void) 117 { 118 return get_timer(0); 119 } 120 121 /* 122 * This function is derived from PowerPC code (timebase clock frequency). 123 * On ARM it returns the number of timer ticks per second. 124 */ 125 unsigned long get_tbclk(void) 126 { 127 return CONFIG_SYS_HZ; 128 } 129