Wolfgang Denk | d86ec38 | 2006-03-13 12:37:35 +0100 | [diff] [blame] | 1 | /* |
| 2 | * (C) Copyright 2003 |
| 3 | * Texas Instruments <www.ti.com> |
| 4 | * |
| 5 | * (C) Copyright 2002 |
| 6 | * Sysgo Real-Time Solutions, GmbH <www.elinos.com> |
| 7 | * Marius Groeger <mgroeger@sysgo.de> |
| 8 | * |
| 9 | * (C) Copyright 2002 |
| 10 | * Sysgo Real-Time Solutions, GmbH <www.elinos.com> |
| 11 | * Alex Zuepke <azu@sysgo.de> |
| 12 | * |
| 13 | * (C) Copyright 2002-2004 |
| 14 | * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> |
| 15 | * |
| 16 | * (C) Copyright 2004 |
| 17 | * Philippe Robin, ARM Ltd. <philippe.robin@arm.com> |
| 18 | * |
| 19 | * See file CREDITS for list of people who contributed to this |
| 20 | * project. |
| 21 | * |
| 22 | * This program is free software; you can redistribute it and/or |
| 23 | * modify it under the terms of the GNU General Public License as |
| 24 | * published by the Free Software Foundation; either version 2 of |
| 25 | * the License, or (at your option) any later version. |
| 26 | * |
| 27 | * This program is distributed in the hope that it will be useful, |
| 28 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 29 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 30 | * GNU General Public License for more details. |
| 31 | * |
| 32 | * You should have received a copy of the GNU General Public License |
| 33 | * along with this program; if not, write to the Free Software |
| 34 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
| 35 | * MA 02111-1307 USA |
| 36 | */ |
| 37 | |
| 38 | #include <common.h> |
| 39 | #include <arm926ejs.h> |
| 40 | |
| 41 | #define TIMER_LOAD_VAL 0xffffffff |
| 42 | |
| 43 | /* macro to read the 32 bit timer */ |
| 44 | #define READ_TIMER (*(volatile ulong *)(CFG_TIMERBASE+8)) |
| 45 | |
| 46 | static ulong timestamp; |
| 47 | static ulong lastdec; |
| 48 | |
| 49 | int timer_init (void) |
| 50 | { |
| 51 | int32_t val; |
| 52 | |
| 53 | /* Start the decrementer ticking down from 0xffffffff */ |
| 54 | *((int32_t *) (CFG_TIMERBASE + LOAD_TIM)) = TIMER_LOAD_VAL; |
| 55 | val = MPUTIM_ST | MPUTIM_AR | MPUTIM_CLOCK_ENABLE | (CFG_PVT << MPUTIM_PTV_BIT); |
| 56 | *((int32_t *) (CFG_TIMERBASE + CNTL_TIMER)) = val; |
| 57 | |
| 58 | /* init the timestamp and lastdec value */ |
| 59 | reset_timer_masked(); |
| 60 | |
| 61 | return 0; |
| 62 | } |
| 63 | |
| 64 | /* |
| 65 | * timer without interrupts |
| 66 | */ |
| 67 | |
| 68 | void reset_timer (void) |
| 69 | { |
| 70 | reset_timer_masked (); |
| 71 | } |
| 72 | |
| 73 | ulong get_timer (ulong base) |
| 74 | { |
| 75 | return get_timer_masked () - base; |
| 76 | } |
| 77 | |
| 78 | void set_timer (ulong t) |
| 79 | { |
| 80 | timestamp = t; |
| 81 | } |
| 82 | |
| 83 | /* delay x useconds AND perserve advance timstamp value */ |
| 84 | void udelay (unsigned long usec) |
| 85 | { |
| 86 | ulong tmo, tmp; |
| 87 | |
| 88 | if(usec >= 1000){ /* if "big" number, spread normalization to seconds */ |
| 89 | tmo = usec / 1000; /* start to normalize for usec to ticks per sec */ |
| 90 | tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */ |
| 91 | tmo /= 1000; /* finish normalize. */ |
| 92 | }else{ /* else small number, don't kill it prior to HZ multiply */ |
| 93 | tmo = usec * CFG_HZ; |
| 94 | tmo /= (1000*1000); |
| 95 | } |
| 96 | |
| 97 | tmp = get_timer (0); /* get current timestamp */ |
| 98 | if( (tmo + tmp + 1) < tmp ) /* if setting this fordward will roll time stamp */ |
| 99 | reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastdec value */ |
| 100 | else |
| 101 | tmo += tmp; /* else, set advancing stamp wake up time */ |
| 102 | |
| 103 | while (get_timer_masked () < tmo)/* loop till event */ |
| 104 | /*NOP*/; |
| 105 | } |
| 106 | |
| 107 | void reset_timer_masked (void) |
| 108 | { |
| 109 | /* reset time */ |
| 110 | lastdec = READ_TIMER; /* capure current decrementer value time */ |
| 111 | timestamp = 0; /* start "advancing" time stamp from 0 */ |
| 112 | } |
| 113 | |
| 114 | ulong get_timer_masked (void) |
| 115 | { |
| 116 | ulong now = READ_TIMER; /* current tick value */ |
| 117 | |
| 118 | if (lastdec >= now) { /* normal mode (non roll) */ |
| 119 | /* normal mode */ |
| 120 | timestamp += lastdec - now; /* move stamp fordward with absoulte diff ticks */ |
| 121 | } else { /* we have overflow of the count down timer */ |
| 122 | /* nts = ts + ld + (TLV - now) |
| 123 | * ts=old stamp, ld=time that passed before passing through -1 |
| 124 | * (TLV-now) amount of time after passing though -1 |
| 125 | * nts = new "advancing time stamp"...it could also roll and cause problems. |
| 126 | */ |
| 127 | timestamp += lastdec + TIMER_LOAD_VAL - now; |
| 128 | } |
| 129 | lastdec = now; |
| 130 | |
| 131 | return timestamp; |
| 132 | } |
| 133 | |
| 134 | /* waits specified delay value and resets timestamp */ |
| 135 | void udelay_masked (unsigned long usec) |
| 136 | { |
| 137 | ulong tmo; |
| 138 | ulong endtime; |
| 139 | signed long diff; |
| 140 | |
| 141 | if (usec >= 1000) { /* if "big" number, spread normalization to seconds */ |
| 142 | tmo = usec / 1000; /* start to normalize for usec to ticks per sec */ |
| 143 | tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */ |
| 144 | tmo /= 1000; /* finish normalize. */ |
| 145 | } else { /* else small number, don't kill it prior to HZ multiply */ |
| 146 | tmo = usec * CFG_HZ; |
| 147 | tmo /= (1000*1000); |
| 148 | } |
| 149 | |
| 150 | endtime = get_timer_masked () + tmo; |
| 151 | |
| 152 | do { |
| 153 | ulong now = get_timer_masked (); |
| 154 | diff = endtime - now; |
| 155 | } while (diff >= 0); |
| 156 | } |
| 157 | |
| 158 | /* |
| 159 | * This function is derived from PowerPC code (read timebase as long long). |
| 160 | * On ARM it just returns the timer value. |
| 161 | */ |
| 162 | unsigned long long get_ticks(void) |
| 163 | { |
| 164 | return get_timer(0); |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * This function is derived from PowerPC code (timebase clock frequency). |
| 169 | * On ARM it returns the number of timer ticks per second. |
| 170 | */ |
| 171 | ulong get_tbclk (void) |
| 172 | { |
| 173 | ulong tbclk; |
| 174 | |
| 175 | tbclk = CFG_HZ; |
| 176 | return tbclk; |
| 177 | } |