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 * SPDX-License-Identifier: GPL-2.0+ 21 */ 22 23 #include <common.h> 24 #include <div64.h> 25 #include <asm/io.h> 26 #include <asm/arch/imx-regs.h> 27 #include <asm/arch/clock.h> 28 29 DECLARE_GLOBAL_DATA_PTR; 30 31 #define timestamp (gd->arch.tbl) 32 #define lastinc (gd->arch.lastinc) 33 34 /* 35 * "time" is measured in 1 / CONFIG_SYS_HZ seconds, 36 * "tick" is internal timer period 37 */ 38 #ifdef CONFIG_MX25_TIMER_HIGH_PRECISION 39 /* ~0.4% error - measured with stop-watch on 100s boot-delay */ 40 static inline unsigned long long tick_to_time(unsigned long long tick) 41 { 42 tick *= CONFIG_SYS_HZ; 43 do_div(tick, MXC_CLK32); 44 return tick; 45 } 46 47 static inline unsigned long long time_to_tick(unsigned long long time) 48 { 49 time *= MXC_CLK32; 50 do_div(time, CONFIG_SYS_HZ); 51 return time; 52 } 53 54 static inline unsigned long long us_to_tick(unsigned long long us) 55 { 56 us = us * MXC_CLK32 + 999999; 57 do_div(us, 1000000); 58 return us; 59 } 60 #else 61 /* ~2% error */ 62 #define TICK_PER_TIME ((MXC_CLK32 + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ) 63 #define US_PER_TICK (1000000 / MXC_CLK32) 64 65 static inline unsigned long long tick_to_time(unsigned long long tick) 66 { 67 do_div(tick, TICK_PER_TIME); 68 return tick; 69 } 70 71 static inline unsigned long long time_to_tick(unsigned long long time) 72 { 73 return time * TICK_PER_TIME; 74 } 75 76 static inline unsigned long long us_to_tick(unsigned long long us) 77 { 78 us += US_PER_TICK - 1; 79 do_div(us, US_PER_TICK); 80 return us; 81 } 82 #endif 83 84 /* nothing really to do with interrupts, just starts up a counter. */ 85 /* The 32KHz 32-bit timer overruns in 134217 seconds */ 86 int timer_init(void) 87 { 88 int i; 89 struct gpt_regs *gpt = (struct gpt_regs *)IMX_GPT1_BASE; 90 struct ccm_regs *ccm = (struct ccm_regs *)IMX_CCM_BASE; 91 92 /* setup GP Timer 1 */ 93 writel(GPT_CTRL_SWR, &gpt->ctrl); 94 95 writel(readl(&ccm->cgr1) | CCM_CGR1_GPT1, &ccm->cgr1); 96 97 for (i = 0; i < 100; i++) 98 writel(0, &gpt->ctrl); /* We have no udelay by now */ 99 writel(0, &gpt->pre); /* prescaler = 1 */ 100 /* Freerun Mode, 32KHz input */ 101 writel(readl(&gpt->ctrl) | GPT_CTRL_CLKSOURCE_32 | GPT_CTRL_FRR, 102 &gpt->ctrl); 103 writel(readl(&gpt->ctrl) | GPT_CTRL_TEN, &gpt->ctrl); 104 105 return 0; 106 } 107 108 unsigned long long get_ticks(void) 109 { 110 struct gpt_regs *gpt = (struct gpt_regs *)IMX_GPT1_BASE; 111 ulong now = readl(&gpt->counter); /* current tick value */ 112 113 if (now >= lastinc) { 114 /* 115 * normal mode (non roll) 116 * move stamp forward with absolut diff ticks 117 */ 118 timestamp += (now - lastinc); 119 } else { 120 /* we have rollover of incrementer */ 121 timestamp += (0xFFFFFFFF - lastinc) + now; 122 } 123 lastinc = now; 124 return timestamp; 125 } 126 127 ulong get_timer_masked(void) 128 { 129 /* 130 * get_ticks() returns a long long (64 bit), it wraps in 131 * 2^64 / MXC_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ 132 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in 133 * 5 * 10^6 days - long enough. 134 */ 135 return tick_to_time(get_ticks()); 136 } 137 138 ulong get_timer(ulong base) 139 { 140 return get_timer_masked() - base; 141 } 142 143 /* delay x useconds AND preserve advance timstamp value */ 144 void __udelay(unsigned long usec) 145 { 146 unsigned long long tmp; 147 ulong tmo; 148 149 tmo = us_to_tick(usec); 150 tmp = get_ticks() + tmo; /* get current timestamp */ 151 152 while (get_ticks() < tmp) /* loop till event */ 153 /*NOP*/; 154 } 155 156 /* 157 * This function is derived from PowerPC code (timebase clock frequency). 158 * On ARM it returns the number of timer ticks per second. 159 */ 160 ulong get_tbclk(void) 161 { 162 ulong tbclk; 163 164 tbclk = MXC_CLK32; 165 return tbclk; 166 } 167