3 * Texas Instruments <www.ti.com>
6 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
7 * Marius Groeger <mgroeger@sysgo.de>
10 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
11 * Alex Zuepke <azu@sysgo.de>
13 * (C) Copyright 2002-2004
14 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
17 * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
19 * See file CREDITS for list of people who contributed to this
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.
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.
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,
40 #include <arm926ejs.h>
42 #define TIMER_LOAD_VAL 0xffffffff
44 /* macro to read the 32 bit timer */
45 #define READ_TIMER readl(CONFIG_SYS_TIMERBASE + 20)
47 static ulong timestamp;
50 /* nothing really to do with interrupts, just starts up a counter. */
53 /* Load timer with initial value */
54 writel(TIMER_LOAD_VAL, CONFIG_SYS_TIMERBASE + 16);
57 * Set timer to be enabled, free-running, no interrupts, 256 divider,
60 writel(0x8a, CONFIG_SYS_TIMERBASE + 24);
62 /* init the timestamp and lastdec value */
69 * timer without interrupts
71 void reset_timer(void)
76 ulong get_timer(ulong base)
78 return get_timer_masked() - base;
81 void set_timer(ulong t)
86 /* delay x useconds AND perserve advance timstamp value */
87 void udelay(unsigned long usec)
92 /* if "big" number, spread normalization to seconds */
93 tmo = usec / 1000; /* start to normalize */
94 tmo *= CONFIG_SYS_HZ; /* find number of "ticks" */
95 tmo /= 1000; /* finish normalize. */
97 /* small number, don't kill it prior to HZ multiply */
98 tmo = usec * CONFIG_SYS_HZ;
102 tmp = get_timer(0); /* get current timestamp */
103 if ((tmo + tmp + 1) < tmp) /* will roll time stamp? */
104 reset_timer_masked(); /* reset to 0, set lastdec value */
108 while (get_timer_masked() < tmo)
112 void reset_timer_masked(void)
115 lastdec = READ_TIMER; /* capure current decrementer value time */
116 timestamp = 0; /* start "advancing" time stamp from 0 */
119 ulong get_timer_masked(void)
121 ulong now = READ_TIMER; /* current tick value */
123 if (lastdec >= now) { /* normal mode (non roll) */
124 /* move stamp fordward */
125 timestamp += lastdec - now;
128 * An overflow is expected.
129 * nts = ts + ld + (TLV - now)
130 * ts=old stamp, ld=time that passed before passing through -1
131 * (TLV-now) amount of time after passing though -1
132 * nts = new "advancing time stamp"...it could also roll
134 timestamp += lastdec + TIMER_LOAD_VAL - now;
141 /* waits specified delay value and resets timestamp */
142 void udelay_masked(unsigned long usec)
147 /* if "big" number, spread normalization to seconds */
148 tmo = usec / 1000; /* start to normalize */
149 tmo *= CONFIG_SYS_HZ; /* find number of "ticks" */
150 tmo /= 1000; /* finish normalize. */
152 /* else small number, don't kill it prior to HZ multiply */
153 tmo = usec * CONFIG_SYS_HZ;
157 reset_timer_masked();
158 /* set "advancing" timestamp to 0, set lastdec vaule */
160 while (get_timer_masked() < tmo)
165 * This function is derived from PowerPC code (read timebase as long long).
166 * On ARM it just returns the timer value.
168 unsigned long long get_ticks(void)
174 * This function is derived from PowerPC code (timebase clock frequency).
175 * On ARM it returns the number of timer ticks per second.
177 ulong get_tbclk(void)
181 tbclk = CONFIG_SYS_HZ;