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 static unsigned long count_value; 33 34 /* Internal tick units */ 35 static unsigned long long timestamp; /* Monotonic incrementing timer */ 36 static unsigned long lastdec; /* Last decremneter snapshot */ 37 38 /* macro to read the 16 bit timer */ 39 static inline struct s5p_timer *s5p_get_base_timer(void) 40 { 41 return (struct s5p_timer *)samsung_get_base_timer(); 42 } 43 44 int timer_init(void) 45 { 46 /* PWM Timer 4 */ 47 pwm_init(4, MUX_DIV_2, 0); 48 pwm_config(4, 0, 0); 49 pwm_enable(4); 50 51 return 0; 52 } 53 54 /* 55 * timer without interrupts 56 */ 57 void reset_timer(void) 58 { 59 reset_timer_masked(); 60 } 61 62 unsigned long get_timer(unsigned long base) 63 { 64 return get_timer_masked() - base; 65 } 66 67 void set_timer(unsigned long t) 68 { 69 timestamp = t; 70 } 71 72 /* delay x useconds */ 73 void __udelay(unsigned long usec) 74 { 75 struct s5p_timer *const timer = s5p_get_base_timer(); 76 unsigned long tmo, tmp; 77 78 count_value = readl(&timer->tcntb4); 79 80 if (usec >= 1000) { 81 /* 82 * if "big" number, spread normalization 83 * to seconds 84 * 1. start to normalize for usec to ticks per sec 85 * 2. find number of "ticks" to wait to achieve target 86 * 3. finish normalize. 87 */ 88 tmo = usec / 1000; 89 tmo *= (CONFIG_SYS_HZ * count_value / 10); 90 tmo /= 1000; 91 } else { 92 /* else small number, don't kill it prior to HZ multiply */ 93 tmo = usec * CONFIG_SYS_HZ * count_value / 10; 94 tmo /= (1000 * 1000); 95 } 96 97 /* get current timestamp */ 98 tmp = get_timer(0); 99 100 /* if setting this fordward will roll time stamp */ 101 /* reset "advancing" timestamp to 0, set lastdec value */ 102 /* else, set advancing stamp wake up time */ 103 if ((tmo + tmp + 1) < tmp) 104 reset_timer_masked(); 105 else 106 tmo += tmp; 107 108 /* loop till event */ 109 while (get_timer_masked() < tmo) 110 ; /* nop */ 111 } 112 113 void reset_timer_masked(void) 114 { 115 struct s5p_timer *const timer = s5p_get_base_timer(); 116 117 /* reset time */ 118 lastdec = readl(&timer->tcnto4); 119 timestamp = 0; 120 } 121 122 unsigned long get_timer_masked(void) 123 { 124 struct s5p_timer *const timer = s5p_get_base_timer(); 125 unsigned long now = readl(&timer->tcnto4); 126 127 if (lastdec >= now) 128 timestamp += lastdec - now; 129 else 130 timestamp += lastdec + count_value - now; 131 132 lastdec = now; 133 134 return timestamp; 135 } 136 137 /* 138 * This function is derived from PowerPC code (read timebase as long long). 139 * On ARM it just returns the timer value. 140 */ 141 unsigned long long get_ticks(void) 142 { 143 return get_timer(0); 144 } 145 146 /* 147 * This function is derived from PowerPC code (timebase clock frequency). 148 * On ARM it returns the number of timer ticks per second. 149 */ 150 unsigned long get_tbclk(void) 151 { 152 return CONFIG_SYS_HZ; 153 } 154