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 * (C) Copyright 2009 DENX Software Engineering 17 * Author: John Rigby <jrigby@gmail.com> 18 * Add support for MX25 19 * 20 * See file CREDITS for list of people who contributed to this 21 * project. 22 * 23 * This program is free software; you can redistribute it and/or 24 * modify it under the terms of the GNU General Public License as 25 * published by the Free Software Foundation; either version 2 of 26 * the License, or (at your option) any later version. 27 * 28 * This program is distributed in the hope that it will be useful, 29 * but WITHOUT ANY WARRANTY; without even the implied warranty of 30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 31 * GNU General Public License for more details. 32 * 33 * You should have received a copy of the GNU General Public License 34 * along with this program; if not, write to the Free Software 35 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 36 * MA 02111-1307 USA 37 */ 38 39 #include <common.h> 40 #include <div64.h> 41 #include <asm/io.h> 42 #include <asm/arch/imx-regs.h> 43 44 DECLARE_GLOBAL_DATA_PTR; 45 46 #define timestamp (gd->tbl) 47 #define lastinc (gd->lastinc) 48 49 /* 50 * "time" is measured in 1 / CONFIG_SYS_HZ seconds, 51 * "tick" is internal timer period 52 */ 53 #ifdef CONFIG_MX25_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_MX25_CLK32); 59 return tick; 60 } 61 62 static inline unsigned long long time_to_tick(unsigned long long time) 63 { 64 time *= CONFIG_MX25_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_MX25_CLK32 + 999999; 72 do_div(us, 1000000); 73 return us; 74 } 75 #else 76 /* ~2% error */ 77 #define TICK_PER_TIME ((CONFIG_MX25_CLK32 + CONFIG_SYS_HZ / 2) / \ 78 CONFIG_SYS_HZ) 79 #define US_PER_TICK (1000000 / CONFIG_MX25_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 32KHz 32-bit timer overruns in 134217 seconds */ 102 int timer_init(void) 103 { 104 int i; 105 struct gpt_regs *gpt = (struct gpt_regs *)IMX_GPT1_BASE; 106 struct ccm_regs *ccm = (struct ccm_regs *)IMX_CCM_BASE; 107 108 /* setup GP Timer 1 */ 109 writel(GPT_CTRL_SWR, &gpt->ctrl); 110 111 writel(readl(&ccm->cgr1) | CCM_CGR1_GPT1, &ccm->cgr1); 112 113 for (i = 0; i < 100; i++) 114 writel(0, &gpt->ctrl); /* We have no udelay by now */ 115 writel(0, &gpt->pre); /* prescaler = 1 */ 116 /* Freerun Mode, 32KHz input */ 117 writel(readl(&gpt->ctrl) | GPT_CTRL_CLKSOURCE_32 | GPT_CTRL_FRR, 118 &gpt->ctrl); 119 writel(readl(&gpt->ctrl) | GPT_CTRL_TEN, &gpt->ctrl); 120 121 return 0; 122 } 123 124 unsigned long long get_ticks(void) 125 { 126 struct gpt_regs *gpt = (struct gpt_regs *)IMX_GPT1_BASE; 127 ulong now = readl(&gpt->counter); /* current tick value */ 128 129 if (now >= lastinc) { 130 /* 131 * normal mode (non roll) 132 * move stamp forward with absolut diff ticks 133 */ 134 timestamp += (now - lastinc); 135 } else { 136 /* we have rollover of incrementer */ 137 timestamp += (0xFFFFFFFF - lastinc) + now; 138 } 139 lastinc = now; 140 return timestamp; 141 } 142 143 ulong get_timer_masked(void) 144 { 145 /* 146 * get_ticks() returns a long long (64 bit), it wraps in 147 * 2^64 / CONFIG_MX25_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ 148 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in 149 * 5 * 10^6 days - long enough. 150 */ 151 return tick_to_time(get_ticks()); 152 } 153 154 ulong get_timer(ulong base) 155 { 156 return get_timer_masked() - base; 157 } 158 159 /* delay x useconds AND preserve advance timstamp value */ 160 void __udelay(unsigned long usec) 161 { 162 unsigned long long tmp; 163 ulong tmo; 164 165 tmo = us_to_tick(usec); 166 tmp = get_ticks() + tmo; /* get current timestamp */ 167 168 while (get_ticks() < tmp) /* loop till event */ 169 /*NOP*/; 170 } 171 172 /* 173 * This function is derived from PowerPC code (timebase clock frequency). 174 * On ARM it returns the number of timer ticks per second. 175 */ 176 ulong get_tbclk(void) 177 { 178 ulong tbclk; 179 180 tbclk = CONFIG_MX25_CLK32; 181 return tbclk; 182 } 183