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 DECLARE_GLOBAL_DATA_PTR; 47 48 #define timestamp gd->tbl 49 #define lastinc gd->lastinc 50 51 /* 52 * "time" is measured in 1 / CONFIG_SYS_HZ seconds, 53 * "tick" is internal timer period 54 */ 55 #ifdef CONFIG_MX27_TIMER_HIGH_PRECISION 56 /* ~0.4% error - measured with stop-watch on 100s boot-delay */ 57 static inline unsigned long long tick_to_time(unsigned long long tick) 58 { 59 tick *= CONFIG_SYS_HZ; 60 do_div(tick, CONFIG_MX27_CLK32); 61 return tick; 62 } 63 64 static inline unsigned long long time_to_tick(unsigned long long time) 65 { 66 time *= CONFIG_MX27_CLK32; 67 do_div(time, CONFIG_SYS_HZ); 68 return time; 69 } 70 71 static inline unsigned long long us_to_tick(unsigned long long us) 72 { 73 us = us * CONFIG_MX27_CLK32 + 999999; 74 do_div(us, 1000000); 75 return us; 76 } 77 #else 78 /* ~2% error */ 79 #define TICK_PER_TIME ((CONFIG_MX27_CLK32 + CONFIG_SYS_HZ / 2) / \ 80 CONFIG_SYS_HZ) 81 #define US_PER_TICK (1000000 / CONFIG_MX27_CLK32) 82 83 static inline unsigned long long tick_to_time(unsigned long long tick) 84 { 85 do_div(tick, TICK_PER_TIME); 86 return tick; 87 } 88 89 static inline unsigned long long time_to_tick(unsigned long long time) 90 { 91 return time * TICK_PER_TIME; 92 } 93 94 static inline unsigned long long us_to_tick(unsigned long long us) 95 { 96 us += US_PER_TICK - 1; 97 do_div(us, US_PER_TICK); 98 return us; 99 } 100 #endif 101 102 /* nothing really to do with interrupts, just starts up a counter. */ 103 /* The 32768Hz 32-bit timer overruns in 131072 seconds */ 104 int timer_init(void) 105 { 106 int i; 107 struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; 108 struct pll_regs *pll = (struct pll_regs *)IMX_PLL_BASE; 109 110 /* setup GP Timer 1 */ 111 writel(GPTCR_SWR, ®s->gpt_tctl); 112 113 writel(readl(&pll->pccr0) | PCCR0_GPT1_EN, &pll->pccr0); 114 writel(readl(&pll->pccr1) | PCCR1_PERCLK1_EN, &pll->pccr1); 115 116 for (i = 0; i < 100; i++) 117 writel(0, ®s->gpt_tctl); /* We have no udelay by now */ 118 writel(0, ®s->gpt_tprer); /* 32Khz */ 119 /* Freerun Mode, PERCLK1 input */ 120 writel(readl(®s->gpt_tctl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR, 121 ®s->gpt_tctl); 122 writel(readl(®s->gpt_tctl) | GPTCR_TEN, ®s->gpt_tctl); 123 124 return 0; 125 } 126 127 void reset_timer_masked(void) 128 { 129 struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; 130 /* reset time */ 131 /* capture current incrementer value time */ 132 lastinc = readl(®s->gpt_tcn); 133 timestamp = 0; /* start "advancing" time stamp from 0 */ 134 } 135 136 void reset_timer(void) 137 { 138 reset_timer_masked(); 139 } 140 141 unsigned long long get_ticks (void) 142 { 143 struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; 144 ulong now = readl(®s->gpt_tcn); /* current tick value */ 145 146 if (now >= lastinc) { 147 /* 148 * normal mode (non roll) 149 * move stamp forward with absolut diff ticks 150 */ 151 timestamp += (now - lastinc); 152 } else { 153 /* we have rollover of incrementer */ 154 timestamp += (0xFFFFFFFF - lastinc) + now; 155 } 156 lastinc = now; 157 return timestamp; 158 } 159 160 ulong get_timer_masked (void) 161 { 162 /* 163 * get_ticks() returns a long long (64 bit), it wraps in 164 * 2^64 / CONFIG_MX27_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ 165 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in 166 * 5 * 10^6 days - long enough. 167 */ 168 return tick_to_time(get_ticks()); 169 } 170 171 ulong get_timer (ulong base) 172 { 173 return get_timer_masked () - base; 174 } 175 176 void set_timer (ulong t) 177 { 178 timestamp = time_to_tick(t); 179 } 180 181 /* delay x useconds AND preserve advance timstamp value */ 182 void __udelay (unsigned long usec) 183 { 184 unsigned long long tmp; 185 ulong tmo; 186 187 tmo = us_to_tick(usec); 188 tmp = get_ticks() + tmo; /* get current timestamp */ 189 190 while (get_ticks() < tmp) /* loop till event */ 191 /*NOP*/; 192 } 193