1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2002 4 * Sysgo Real-Time Solutions, GmbH <www.elinos.com> 5 * Marius Groeger <mgroeger@sysgo.de> 6 * 7 * (C) Copyright 2002 8 * David Mueller, ELSOFT AG, <d.mueller@elsoft.ch> 9 * 10 * (C) Copyright 2003 11 * Texas Instruments, <www.ti.com> 12 * Kshitij Gupta <Kshitij@ti.com> 13 * 14 * (C) Copyright 2004 15 * ARM Ltd. 16 * Philippe Robin, <philippe.robin@arm.com> 17 */ 18 19 #include <common.h> 20 #include <div64.h> 21 22 #ifdef CONFIG_ARCH_CINTEGRATOR 23 #define DIV_CLOCK_INIT 1 24 #define TIMER_LOAD_VAL 0xFFFFFFFFL 25 #else 26 #define DIV_CLOCK_INIT 256 27 #define TIMER_LOAD_VAL 0x0000FFFFL 28 #endif 29 /* The Integrator/CP timer1 is clocked at 1MHz 30 * can be divided by 16 or 256 31 * and can be set up as a 32-bit timer 32 */ 33 /* U-Boot expects a 32 bit timer, running at CONFIG_SYS_HZ */ 34 /* Keep total timer count to avoid losing decrements < div_timer */ 35 static unsigned long long total_count = 0; 36 static unsigned long long lastdec; /* Timer reading at last call */ 37 /* Divisor applied to timer clock */ 38 static unsigned long long div_clock = DIV_CLOCK_INIT; 39 static unsigned long long div_timer = 1; /* Divisor to convert timer reading 40 * change to U-Boot ticks 41 */ 42 /* CONFIG_SYS_HZ = CONFIG_SYS_HZ_CLOCK/(div_clock * div_timer) */ 43 static ulong timestamp; /* U-Boot ticks since startup */ 44 45 #define READ_TIMER (*(volatile ulong *)(CONFIG_SYS_TIMERBASE+4)) 46 47 /* all function return values in U-Boot ticks i.e. (1/CONFIG_SYS_HZ) sec 48 * - unless otherwise stated 49 */ 50 51 /* starts up a counter 52 * - the Integrator/CP timer can be set up to issue an interrupt */ 53 int timer_init (void) 54 { 55 /* Load timer with initial value */ 56 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 0) = TIMER_LOAD_VAL; 57 #ifdef CONFIG_ARCH_CINTEGRATOR 58 /* Set timer to be 59 * enabled 1 60 * periodic 1 61 * no interrupts 0 62 * X 0 63 * divider 1 00 == less rounding error 64 * 32 bit 1 65 * wrapping 0 66 */ 67 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x000000C2; 68 #else 69 /* Set timer to be 70 * enabled 1 71 * free-running 0 72 * XX 00 73 * divider 256 10 74 * XX 00 75 */ 76 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x00000088; 77 #endif 78 79 /* init the timestamp */ 80 total_count = 0ULL; 81 /* capure current decrementer value */ 82 lastdec = READ_TIMER; 83 /* start "advancing" time stamp from 0 */ 84 timestamp = 0L; 85 86 div_timer = CONFIG_SYS_HZ_CLOCK; 87 do_div(div_timer, CONFIG_SYS_HZ); 88 do_div(div_timer, div_clock); 89 90 return (0); 91 } 92 93 /* 94 * timer without interrupts 95 */ 96 97 /* converts the timer reading to U-Boot ticks */ 98 /* the timestamp is the number of ticks since reset */ 99 static ulong get_timer_masked (void) 100 { 101 /* get current count */ 102 unsigned long long now = READ_TIMER; 103 104 if(now > lastdec) { 105 /* Must have wrapped */ 106 total_count += lastdec + TIMER_LOAD_VAL + 1 - now; 107 } else { 108 total_count += lastdec - now; 109 } 110 lastdec = now; 111 112 /* Reuse "now" */ 113 now = total_count; 114 do_div(now, div_timer); 115 timestamp = now; 116 117 return timestamp; 118 } 119 120 ulong get_timer (ulong base_ticks) 121 { 122 return get_timer_masked () - base_ticks; 123 } 124 125 /* delay usec useconds */ 126 void __udelay (unsigned long usec) 127 { 128 ulong tmo, tmp; 129 130 /* Convert to U-Boot ticks */ 131 tmo = usec * CONFIG_SYS_HZ; 132 tmo /= (1000000L); 133 134 tmp = get_timer_masked(); /* get current timestamp */ 135 tmo += tmp; /* form target timestamp */ 136 137 while (get_timer_masked () < tmo) {/* loop till event */ 138 /*NOP*/; 139 } 140 } 141 142 /* 143 * This function is derived from PowerPC code (read timebase as long long). 144 * On ARM it just returns the timer value. 145 */ 146 unsigned long long get_ticks(void) 147 { 148 return get_timer(0); 149 } 150 151 /* 152 * Return the timebase clock frequency 153 * i.e. how often the timer decrements 154 */ 155 ulong get_tbclk (void) 156 { 157 unsigned long long tmp = CONFIG_SYS_HZ_CLOCK; 158 159 do_div(tmp, div_clock); 160 161 return tmp; 162 } 163