1 /* 2 * Copyright (C) 2015 Freescale Semiconductor, Inc. 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 * 6 * The file use ls102xa/timer.c as a reference. 7 */ 8 9 #include <common.h> 10 #include <asm/io.h> 11 #include <div64.h> 12 #include <asm/arch/imx-regs.h> 13 #include <asm/arch/sys_proto.h> 14 #include <asm/mach-imx/syscounter.h> 15 16 DECLARE_GLOBAL_DATA_PTR; 17 18 /* 19 * This function is intended for SHORT delays only. 20 * It will overflow at around 10 seconds @ 400MHz, 21 * or 20 seconds @ 200MHz. 22 */ 23 unsigned long usec2ticks(unsigned long usec) 24 { 25 ulong ticks; 26 27 if (usec < 1000) 28 ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000; 29 else 30 ticks = ((usec / 10) * (get_tbclk() / 100000)); 31 32 return ticks; 33 } 34 35 static inline unsigned long long tick_to_time(unsigned long long tick) 36 { 37 unsigned long freq; 38 39 asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq)); 40 41 tick *= CONFIG_SYS_HZ; 42 do_div(tick, freq); 43 44 return tick; 45 } 46 47 static inline unsigned long long us_to_tick(unsigned long long usec) 48 { 49 unsigned long freq; 50 51 asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq)); 52 53 usec = usec * freq + 999999; 54 do_div(usec, 1000000); 55 56 return usec; 57 } 58 59 int timer_init(void) 60 { 61 struct sctr_regs *sctr = (struct sctr_regs *)SCTR_BASE_ADDR; 62 unsigned long val, freq; 63 64 freq = CONFIG_SC_TIMER_CLK; 65 asm("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq)); 66 67 writel(freq, &sctr->cntfid0); 68 69 /* Enable system counter */ 70 val = readl(&sctr->cntcr); 71 val &= ~(SC_CNTCR_FREQ0 | SC_CNTCR_FREQ1); 72 val |= SC_CNTCR_FREQ0 | SC_CNTCR_ENABLE | SC_CNTCR_HDBG; 73 writel(val, &sctr->cntcr); 74 75 gd->arch.tbl = 0; 76 gd->arch.tbu = 0; 77 78 return 0; 79 } 80 81 unsigned long long get_ticks(void) 82 { 83 unsigned long long now; 84 85 asm("mrrc p15, 0, %Q0, %R0, c14" : "=r" (now)); 86 87 gd->arch.tbl = (unsigned long)(now & 0xffffffff); 88 gd->arch.tbu = (unsigned long)(now >> 32); 89 90 return now; 91 } 92 93 ulong get_timer_masked(void) 94 { 95 return tick_to_time(get_ticks()); 96 } 97 98 ulong get_timer(ulong base) 99 { 100 return get_timer_masked() - base; 101 } 102 103 void __udelay(unsigned long usec) 104 { 105 unsigned long long tmp; 106 ulong tmo; 107 108 tmo = us_to_tick(usec); 109 tmp = get_ticks() + tmo; /* get current timestamp */ 110 111 while (get_ticks() < tmp) /* loop till event */ 112 /*NOP*/; 113 } 114 115 /* 116 * This function is derived from PowerPC code (timebase clock frequency). 117 * On ARM it returns the number of timer ticks per second. 118 */ 119 ulong get_tbclk(void) 120 { 121 unsigned long freq; 122 123 asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq)); 124 125 return freq; 126 } 127