1 /* 2 * (C) Copyright 2002 3 * Sysgo Real-Time Solutions, GmbH <www.elinos.com> 4 * Marius Groeger <mgroeger@sysgo.de> 5 * 6 * (C) Copyright 2002 7 * Sysgo Real-Time Solutions, GmbH <www.elinos.com> 8 * Alex Zuepke <azu@sysgo.de> 9 * 10 * (C) Copyright 2002 11 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> 12 * 13 * (C) Copyright 2009 14 * Ilya Yanok, Emcraft Systems Ltd, <yanok@emcraft.com> 15 * 16 * See file CREDITS for list of people who contributed to this 17 * project. 18 * 19 * This program is free software; you can redistribute it and/or 20 * modify it under the terms of the GNU General Public License as 21 * published by the Free Software Foundation; either version 2 of 22 * the License, or (at your option) any later version. 23 * 24 * This program is distributed in the hope that it will be useful, 25 * but WITHOUT ANY WARRANTY; without even the implied warranty of 26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 27 * GNU General Public License for more details. 28 * 29 * You should have received a copy of the GNU General Public License 30 * along with this program; if not, write to the Free Software 31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 32 * MA 02111-1307 USA 33 */ 34 35 #include <common.h> 36 #include <div64.h> 37 #include <asm/io.h> 38 #include <asm/arch/imx-regs.h> 39 40 /* General purpose timers bitfields */ 41 #define GPTCR_SWR (1 << 15) /* Software reset */ 42 #define GPTCR_FRR (1 << 8) /* Freerun / restart */ 43 #define GPTCR_CLKSOURCE_32 (4 << 1) /* Clock source */ 44 #define GPTCR_TEN 1 /* Timer enable */ 45 46 static ulong timestamp; 47 static ulong lastinc; 48 49 /* 50 * "time" is measured in 1 / CONFIG_SYS_HZ seconds, 51 * "tick" is internal timer period 52 */ 53 #ifdef CONFIG_MX27_TIMER_HIGH_PRECISION 54 /* ~0.4% error - measured with stop-watch on 100s boot-delay */ 55 static inline unsigned long long tick_to_time(unsigned long long tick) 56 { 57 tick *= CONFIG_SYS_HZ; 58 do_div(tick, CONFIG_MX27_CLK32); 59 return tick; 60 } 61 62 static inline unsigned long long time_to_tick(unsigned long long time) 63 { 64 time *= CONFIG_MX27_CLK32; 65 do_div(time, CONFIG_SYS_HZ); 66 return time; 67 } 68 69 static inline unsigned long long us_to_tick(unsigned long long us) 70 { 71 us = us * CONFIG_MX27_CLK32 + 999999; 72 do_div(us, 1000000); 73 return us; 74 } 75 #else 76 /* ~2% error */ 77 #define TICK_PER_TIME ((CONFIG_MX27_CLK32 + CONFIG_SYS_HZ / 2) / \ 78 CONFIG_SYS_HZ) 79 #define US_PER_TICK (1000000 / CONFIG_MX27_CLK32) 80 81 static inline unsigned long long tick_to_time(unsigned long long tick) 82 { 83 do_div(tick, TICK_PER_TIME); 84 return tick; 85 } 86 87 static inline unsigned long long time_to_tick(unsigned long long time) 88 { 89 return time * TICK_PER_TIME; 90 } 91 92 static inline unsigned long long us_to_tick(unsigned long long us) 93 { 94 us += US_PER_TICK - 1; 95 do_div(us, US_PER_TICK); 96 return us; 97 } 98 #endif 99 100 /* nothing really to do with interrupts, just starts up a counter. */ 101 /* The 32768Hz 32-bit timer overruns in 131072 seconds */ 102 int timer_init(void) 103 { 104 int i; 105 struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; 106 struct pll_regs *pll = (struct pll_regs *)IMX_PLL_BASE; 107 108 /* setup GP Timer 1 */ 109 writel(GPTCR_SWR, ®s->gpt_tctl); 110 111 writel(readl(&pll->pccr0) | PCCR0_GPT1_EN, &pll->pccr0); 112 writel(readl(&pll->pccr1) | PCCR1_PERCLK1_EN, &pll->pccr1); 113 114 for (i = 0; i < 100; i++) 115 writel(0, ®s->gpt_tctl); /* We have no udelay by now */ 116 writel(0, ®s->gpt_tprer); /* 32Khz */ 117 /* Freerun Mode, PERCLK1 input */ 118 writel(readl(®s->gpt_tctl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR, 119 ®s->gpt_tctl); 120 writel(readl(®s->gpt_tctl) | GPTCR_TEN, ®s->gpt_tctl); 121 122 return 0; 123 } 124 125 void reset_timer_masked(void) 126 { 127 struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; 128 /* reset time */ 129 /* capture current incrementer value time */ 130 lastinc = readl(®s->gpt_tcn); 131 timestamp = 0; /* start "advancing" time stamp from 0 */ 132 } 133 134 void reset_timer(void) 135 { 136 reset_timer_masked(); 137 } 138 139 unsigned long long get_ticks (void) 140 { 141 struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; 142 ulong now = readl(®s->gpt_tcn); /* current tick value */ 143 144 if (now >= lastinc) { 145 /* 146 * normal mode (non roll) 147 * move stamp forward with absolut diff ticks 148 */ 149 timestamp += (now - lastinc); 150 } else { 151 /* we have rollover of incrementer */ 152 timestamp += (0xFFFFFFFF - lastinc) + now; 153 } 154 lastinc = now; 155 return timestamp; 156 } 157 158 ulong get_timer_masked (void) 159 { 160 /* 161 * get_ticks() returns a long long (64 bit), it wraps in 162 * 2^64 / CONFIG_MX27_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ 163 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in 164 * 5 * 10^6 days - long enough. 165 */ 166 return tick_to_time(get_ticks()); 167 } 168 169 ulong get_timer (ulong base) 170 { 171 return get_timer_masked () - base; 172 } 173 174 void set_timer (ulong t) 175 { 176 timestamp = time_to_tick(t); 177 } 178 179 /* delay x useconds AND preserve advance timstamp value */ 180 void __udelay (unsigned long usec) 181 { 182 unsigned long long tmp; 183 ulong tmo; 184 185 tmo = us_to_tick(usec); 186 tmp = get_ticks() + tmo; /* get current timestamp */ 187 188 while (get_ticks() < tmp) /* loop till event */ 189 /*NOP*/; 190 } 191