1 /* 2 * (C) Copyright 2007 3 * Sascha Hauer, Pengutronix 4 * 5 * (C) Copyright 2008-2009 Freescale Semiconductor, Inc. 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 <div64.h> 29 #include <asm/arch/imx-regs.h> 30 #include <asm/arch/clock.h> 31 32 DECLARE_GLOBAL_DATA_PTR; 33 34 #define timestamp (gd->tbl) 35 #define lastinc (gd->lastinc) 36 37 /* General purpose timers bitfields */ 38 #define GPTCR_SWR (1<<15) /* Software reset */ 39 #define GPTCR_FRR (1<<9) /* Freerun / restart */ 40 #define GPTCR_CLKSOURCE_32 (0x100<<6) /* Clock source */ 41 #define GPTCR_CLKSOURCE_IPG (0x001<<6) /* Clock source */ 42 #define GPTCR_TEN (1) /* Timer enable */ 43 44 #define TIMER_FREQ_HZ mxc_get_clock(MXC_IPG_CLK) 45 46 static inline unsigned long long tick_to_time(unsigned long long tick) 47 { 48 tick *= CONFIG_SYS_HZ; 49 do_div(tick, TIMER_FREQ_HZ); 50 51 return tick; 52 } 53 54 static inline unsigned long long us_to_tick(unsigned long long usec) 55 { 56 usec *= TIMER_FREQ_HZ; 57 do_div(usec, 1000000); 58 59 return usec; 60 } 61 62 int timer_init(void) 63 { 64 int i; 65 struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; 66 67 /* setup GP Timer 1 */ 68 writel(GPTCR_SWR, &gpt->ctrl); 69 for (i = 0; i < 100; i++) 70 writel(0, &gpt->ctrl); /* We have no udelay by now */ 71 72 writel(0, &gpt->pre); 73 /* Freerun Mode, PERCLK1 input */ 74 writel(readl(&gpt->ctrl) | 75 GPTCR_CLKSOURCE_IPG | GPTCR_TEN, 76 &gpt->ctrl); 77 78 return 0; 79 } 80 81 unsigned long long get_ticks(void) 82 { 83 struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; 84 ulong now = readl(&gpt->counter); /* current tick value */ 85 86 if (now >= lastinc) { 87 /* 88 * normal mode (non roll) 89 * move stamp forward with absolut diff ticks 90 */ 91 timestamp += (now - lastinc); 92 } else { 93 /* we have rollover of incrementer */ 94 timestamp += (0xFFFFFFFF - lastinc) + now; 95 } 96 lastinc = now; 97 return timestamp; 98 } 99 100 ulong get_timer_masked(void) 101 { 102 /* 103 * get_ticks() returns a long long (64 bit), it wraps in 104 * 2^64 / CONFIG_MX25_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ 105 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in 106 * 5 * 10^6 days - long enough. 107 */ 108 return tick_to_time(get_ticks()); 109 } 110 111 ulong get_timer(ulong base) 112 { 113 return get_timer_masked() - base; 114 } 115 116 /* delay x useconds AND preserve advance timstamp value */ 117 void __udelay(unsigned long usec) 118 { 119 unsigned long long tmp; 120 ulong tmo; 121 122 tmo = us_to_tick(usec); 123 tmp = get_ticks() + tmo; /* get current timestamp */ 124 125 while (get_ticks() < tmp) /* loop till event */ 126 /*NOP*/; 127 } 128 129 /* 130 * This function is derived from PowerPC code (timebase clock frequency). 131 * On ARM it returns the number of timer ticks per second. 132 */ 133 ulong get_tbclk(void) 134 { 135 return TIMER_FREQ_HZ; 136 } 137