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 * See file CREDITS for list of people who contributed to this 18 * project. 19 * 20 * This program is free software; you can redistribute it and/or 21 * modify it under the terms of the GNU General Public License as 22 * published by the Free Software Foundation; either version 2 of 23 * the License, or (at your option) any later version. 24 * 25 * This program is distributed in the hope that it will be useful, 26 * but WITHOUT ANY WARRANTY; without even the implied warranty of 27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 28 * GNU General Public License for more details. 29 * 30 * You should have received a copy of the GNU General Public License 31 * along with this program; if not, write to the Free Software 32 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 33 * MA 02111-1307 USA 34 */ 35 36 #include <common.h> 37 #include <div64.h> 38 39 #ifdef CONFIG_ARCH_CINTEGRATOR 40 #define DIV_CLOCK_INIT 1 41 #define TIMER_LOAD_VAL 0xFFFFFFFFL 42 #else 43 #define DIV_CLOCK_INIT 256 44 #define TIMER_LOAD_VAL 0x0000FFFFL 45 #endif 46 /* The Integrator/CP timer1 is clocked at 1MHz 47 * can be divided by 16 or 256 48 * and can be set up as a 32-bit timer 49 */ 50 /* U-Boot expects a 32 bit timer, running at CONFIG_SYS_HZ */ 51 /* Keep total timer count to avoid losing decrements < div_timer */ 52 static unsigned long long total_count = 0; 53 static unsigned long long lastdec; /* Timer reading at last call */ 54 /* Divisor applied to timer clock */ 55 static unsigned long long div_clock = DIV_CLOCK_INIT; 56 static unsigned long long div_timer = 1; /* Divisor to convert timer reading 57 * change to U-Boot ticks 58 */ 59 /* CONFIG_SYS_HZ = CONFIG_SYS_HZ_CLOCK/(div_clock * div_timer) */ 60 static ulong timestamp; /* U-Boot ticks since startup */ 61 62 #define READ_TIMER (*(volatile ulong *)(CONFIG_SYS_TIMERBASE+4)) 63 64 /* all function return values in U-Boot ticks i.e. (1/CONFIG_SYS_HZ) sec 65 * - unless otherwise stated 66 */ 67 68 /* starts up a counter 69 * - the Integrator/CP timer can be set up to issue an interrupt */ 70 int timer_init (void) 71 { 72 /* Load timer with initial value */ 73 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 0) = TIMER_LOAD_VAL; 74 #ifdef CONFIG_ARCH_CINTEGRATOR 75 /* Set timer to be 76 * enabled 1 77 * periodic 1 78 * no interrupts 0 79 * X 0 80 * divider 1 00 == less rounding error 81 * 32 bit 1 82 * wrapping 0 83 */ 84 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x000000C2; 85 #else 86 /* Set timer to be 87 * enabled 1 88 * free-running 0 89 * XX 00 90 * divider 256 10 91 * XX 00 92 */ 93 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x00000088; 94 #endif 95 96 /* init the timestamp */ 97 total_count = 0ULL; 98 reset_timer_masked(); 99 100 div_timer = CONFIG_SYS_HZ_CLOCK; 101 do_div(div_timer, CONFIG_SYS_HZ); 102 do_div(div_timer, div_clock); 103 104 return (0); 105 } 106 107 /* 108 * timer without interrupts 109 */ 110 void reset_timer (void) 111 { 112 reset_timer_masked (); 113 } 114 115 ulong get_timer (ulong base_ticks) 116 { 117 return get_timer_masked () - base_ticks; 118 } 119 120 /* delay usec useconds */ 121 void __udelay (unsigned long usec) 122 { 123 ulong tmo, tmp; 124 125 /* Convert to U-Boot ticks */ 126 tmo = usec * CONFIG_SYS_HZ; 127 tmo /= (1000000L); 128 129 tmp = get_timer_masked(); /* get current timestamp */ 130 tmo += tmp; /* form target timestamp */ 131 132 while (get_timer_masked () < tmo) {/* loop till event */ 133 /*NOP*/; 134 } 135 } 136 137 void reset_timer_masked (void) 138 { 139 /* capure current decrementer value */ 140 lastdec = READ_TIMER; 141 /* start "advancing" time stamp from 0 */ 142 timestamp = 0L; 143 } 144 145 /* converts the timer reading to U-Boot ticks */ 146 /* the timestamp is the number of ticks since reset */ 147 ulong get_timer_masked (void) 148 { 149 /* get current count */ 150 unsigned long long now = READ_TIMER; 151 152 if(now > lastdec) { 153 /* Must have wrapped */ 154 total_count += lastdec + TIMER_LOAD_VAL + 1 - now; 155 } else { 156 total_count += lastdec - now; 157 } 158 lastdec = now; 159 160 /* Reuse "now" */ 161 now = total_count; 162 do_div(now, div_timer); 163 timestamp = now; 164 165 return timestamp; 166 } 167 168 /* waits specified delay value and resets timestamp */ 169 void udelay_masked (unsigned long usec) 170 { 171 udelay(usec); 172 } 173 174 /* 175 * This function is derived from PowerPC code (read timebase as long long). 176 * On ARM it just returns the timer value. 177 */ 178 unsigned long long get_ticks(void) 179 { 180 return get_timer(0); 181 } 182 183 /* 184 * Return the timebase clock frequency 185 * i.e. how often the timer decrements 186 */ 187 ulong get_tbclk (void) 188 { 189 unsigned long long tmp = CONFIG_SYS_HZ_CLOCK; 190 191 do_div(tmp, div_clock); 192 193 return tmp; 194 } 195