1 /* 2 * Copyright 2013 Freescale Semiconductor, Inc. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License as 6 * published by the Free Software Foundation; either version 2 of 7 * the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 17 * MA 02111-1307 USA 18 */ 19 20 #include <common.h> 21 #include <asm/io.h> 22 #include <div64.h> 23 #include <asm/arch/imx-regs.h> 24 #include <asm/arch/clock.h> 25 26 static struct pit_reg *cur_pit = (struct pit_reg *)PIT_BASE_ADDR; 27 28 DECLARE_GLOBAL_DATA_PTR; 29 30 #define TIMER_LOAD_VAL 0xffffffff 31 32 static inline unsigned long long tick_to_time(unsigned long long tick) 33 { 34 tick *= CONFIG_SYS_HZ; 35 do_div(tick, mxc_get_clock(MXC_IPG_CLK)); 36 37 return tick; 38 } 39 40 static inline unsigned long long us_to_tick(unsigned long long usec) 41 { 42 usec = usec * mxc_get_clock(MXC_IPG_CLK) + 999999; 43 do_div(usec, 1000000); 44 45 return usec; 46 } 47 48 int timer_init(void) 49 { 50 __raw_writel(0, &cur_pit->mcr); 51 52 __raw_writel(TIMER_LOAD_VAL, &cur_pit->ldval1); 53 __raw_writel(0, &cur_pit->tctrl1); 54 __raw_writel(1, &cur_pit->tctrl1); 55 56 gd->arch.tbl = 0; 57 gd->arch.tbu = 0; 58 59 return 0; 60 } 61 62 unsigned long long get_ticks(void) 63 { 64 ulong now = TIMER_LOAD_VAL - __raw_readl(&cur_pit->cval1); 65 66 /* increment tbu if tbl has rolled over */ 67 if (now < gd->arch.tbl) 68 gd->arch.tbu++; 69 gd->arch.tbl = now; 70 71 return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl; 72 } 73 74 ulong get_timer_masked(void) 75 { 76 return tick_to_time(get_ticks()); 77 } 78 79 ulong get_timer(ulong base) 80 { 81 return get_timer_masked() - base; 82 } 83 84 /* delay x useconds AND preserve advance timstamp value */ 85 void __udelay(unsigned long usec) 86 { 87 unsigned long long start; 88 ulong tmo; 89 90 start = get_ticks(); /* get current timestamp */ 91 tmo = us_to_tick(usec); /* convert usecs to ticks */ 92 while ((get_ticks() - start) < tmo) 93 ; /* loop till time has passed */ 94 } 95 96 /* 97 * This function is derived from PowerPC code (timebase clock frequency). 98 * On ARM it returns the number of timer ticks per second. 99 */ 100 ulong get_tbclk(void) 101 { 102 return mxc_get_clock(MXC_IPG_CLK); 103 } 104