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 * David Mueller, ELSOFT AG, <d.mueller@elsoft.ch> 8 * 9 * (C) Copyright 2003 10 * Texas Instruments, <www.ti.com> 11 * Kshitij Gupta <Kshitij@ti.com> 12 * 13 * (C) Copyright 2004 14 * ARM Ltd. 15 * Philippe Robin, <philippe.robin@arm.com> 16 * 17 * SPDX-License-Identifier: GPL-2.0+ 18 */ 19 20 #include <common.h> 21 #include <div64.h> 22 23 #ifdef CONFIG_ARCH_CINTEGRATOR 24 #define DIV_CLOCK_INIT 1 25 #define TIMER_LOAD_VAL 0xFFFFFFFFL 26 #else 27 #define DIV_CLOCK_INIT 256 28 #define TIMER_LOAD_VAL 0x0000FFFFL 29 #endif 30 /* The Integrator/CP timer1 is clocked at 1MHz 31 * can be divided by 16 or 256 32 * and can be set up as a 32-bit timer 33 */ 34 /* U-Boot expects a 32 bit timer, running at CONFIG_SYS_HZ */ 35 /* Keep total timer count to avoid losing decrements < div_timer */ 36 static unsigned long long total_count = 0; 37 static unsigned long long lastdec; /* Timer reading at last call */ 38 /* Divisor applied to timer clock */ 39 static unsigned long long div_clock = DIV_CLOCK_INIT; 40 static unsigned long long div_timer = 1; /* Divisor to convert timer reading 41 * change to U-Boot ticks 42 */ 43 /* CONFIG_SYS_HZ = CONFIG_SYS_HZ_CLOCK/(div_clock * div_timer) */ 44 static ulong timestamp; /* U-Boot ticks since startup */ 45 46 #define READ_TIMER (*(volatile ulong *)(CONFIG_SYS_TIMERBASE+4)) 47 48 /* all function return values in U-Boot ticks i.e. (1/CONFIG_SYS_HZ) sec 49 * - unless otherwise stated 50 */ 51 52 /* starts up a counter 53 * - the Integrator/CP timer can be set up to issue an interrupt */ 54 int timer_init (void) 55 { 56 /* Load timer with initial value */ 57 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 0) = TIMER_LOAD_VAL; 58 #ifdef CONFIG_ARCH_CINTEGRATOR 59 /* Set timer to be 60 * enabled 1 61 * periodic 1 62 * no interrupts 0 63 * X 0 64 * divider 1 00 == less rounding error 65 * 32 bit 1 66 * wrapping 0 67 */ 68 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x000000C2; 69 #else 70 /* Set timer to be 71 * enabled 1 72 * free-running 0 73 * XX 00 74 * divider 256 10 75 * XX 00 76 */ 77 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x00000088; 78 #endif 79 80 /* init the timestamp */ 81 total_count = 0ULL; 82 /* capure current decrementer value */ 83 lastdec = READ_TIMER; 84 /* start "advancing" time stamp from 0 */ 85 timestamp = 0L; 86 87 div_timer = CONFIG_SYS_HZ_CLOCK; 88 do_div(div_timer, CONFIG_SYS_HZ); 89 do_div(div_timer, div_clock); 90 91 return (0); 92 } 93 94 /* 95 * timer without interrupts 96 */ 97 ulong get_timer (ulong base_ticks) 98 { 99 return get_timer_masked () - base_ticks; 100 } 101 102 /* delay usec useconds */ 103 void __udelay (unsigned long usec) 104 { 105 ulong tmo, tmp; 106 107 /* Convert to U-Boot ticks */ 108 tmo = usec * CONFIG_SYS_HZ; 109 tmo /= (1000000L); 110 111 tmp = get_timer_masked(); /* get current timestamp */ 112 tmo += tmp; /* form target timestamp */ 113 114 while (get_timer_masked () < tmo) {/* loop till event */ 115 /*NOP*/; 116 } 117 } 118 119 /* converts the timer reading to U-Boot ticks */ 120 /* the timestamp is the number of ticks since reset */ 121 ulong get_timer_masked (void) 122 { 123 /* get current count */ 124 unsigned long long now = READ_TIMER; 125 126 if(now > lastdec) { 127 /* Must have wrapped */ 128 total_count += lastdec + TIMER_LOAD_VAL + 1 - now; 129 } else { 130 total_count += lastdec - now; 131 } 132 lastdec = now; 133 134 /* Reuse "now" */ 135 now = total_count; 136 do_div(now, div_timer); 137 timestamp = now; 138 139 return timestamp; 140 } 141 142 /* waits specified delay value and resets timestamp */ 143 void udelay_masked (unsigned long usec) 144 { 145 udelay(usec); 146 } 147 148 /* 149 * This function is derived from PowerPC code (read timebase as long long). 150 * On ARM it just returns the timer value. 151 */ 152 unsigned long long get_ticks(void) 153 { 154 return get_timer(0); 155 } 156 157 /* 158 * Return the timebase clock frequency 159 * i.e. how often the timer decrements 160 */ 161 ulong get_tbclk (void) 162 { 163 unsigned long long tmp = CONFIG_SYS_HZ_CLOCK; 164 165 do_div(tmp, div_clock); 166 167 return tmp; 168 } 169