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, <gj@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,
39 #include <arm926ejs.h>
41 #define TIMER_LOAD_VAL 0xffffffff
43 /* macro to read the 32 bit timer */
44 #define READ_TIMER (*(volatile ulong *)(CONFIG_SYS_TIMERBASE+4))
46 static ulong timestamp;
49 #define TIMER_ENABLE (1 << 7)
50 #define TIMER_MODE_MSK (1 << 6)
51 #define TIMER_MODE_FR (0 << 6)
52 #define TIMER_MODE_PD (1 << 6)
54 #define TIMER_INT_EN (1 << 5)
55 #define TIMER_PRS_MSK (3 << 2)
56 #define TIMER_PRS_8S (1 << 3)
57 #define TIMER_SIZE_MSK (1 << 2)
58 #define TIMER_ONE_SHT (1 << 0)
64 /* 1st disable the Timer */
65 tmr_ctrl_val = *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8);
66 tmr_ctrl_val &= ~TIMER_ENABLE;
67 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = tmr_ctrl_val;
70 * The Timer Control Register has one Undefined/Shouldn't Use Bit
71 * So we should do read/modify/write Operation
75 * Timer Mode : Free Running
76 * Interrupt : Disabled
77 * Prescale : 8 Stage, Clk/256
78 * Tmr Siz : 16 Bit Counter
79 * Tmr in Wrapping Mode
81 tmr_ctrl_val = *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8);
82 tmr_ctrl_val &= ~(TIMER_MODE_MSK | TIMER_INT_EN | TIMER_PRS_MSK | TIMER_SIZE_MSK | TIMER_ONE_SHT );
83 tmr_ctrl_val |= (TIMER_ENABLE | TIMER_PRS_8S);
85 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = tmr_ctrl_val;
87 /* init the timestamp and lastdec value */
94 * timer without interrupts
97 void reset_timer (void)
99 reset_timer_masked ();
102 ulong get_timer (ulong base)
104 return get_timer_masked () - base;
107 void set_timer (ulong t)
112 /* delay x useconds AND perserve advance timstamp value */
113 void udelay (unsigned long usec)
117 if(usec >= 1000){ /* if "big" number, spread normalization to seconds */
118 tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
119 tmo *= CONFIG_SYS_HZ; /* find number of "ticks" to wait to achieve target */
120 tmo /= 1000; /* finish normalize. */
121 }else{ /* else small number, don't kill it prior to HZ multiply */
122 tmo = usec * CONFIG_SYS_HZ;
126 tmp = get_timer (0); /* get current timestamp */
127 if( (tmo + tmp + 1) < tmp ) /* if setting this fordward will roll time stamp */
128 reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastdec value */
130 tmo += tmp; /* else, set advancing stamp wake up time */
132 while (get_timer_masked () < tmo)/* loop till event */
136 void reset_timer_masked (void)
139 lastdec = READ_TIMER; /* capure current decrementer value time */
140 timestamp = 0; /* start "advancing" time stamp from 0 */
143 ulong get_timer_masked (void)
145 ulong now = READ_TIMER; /* current tick value */
147 if (lastdec >= now) { /* normal mode (non roll) */
149 timestamp += lastdec - now; /* move stamp fordward with absoulte diff ticks */
150 } else { /* we have overflow of the count down timer */
151 /* nts = ts + ld + (TLV - now)
152 * ts=old stamp, ld=time that passed before passing through -1
153 * (TLV-now) amount of time after passing though -1
154 * nts = new "advancing time stamp"...it could also roll and cause problems.
156 timestamp += lastdec + TIMER_LOAD_VAL - now;
163 /* waits specified delay value and resets timestamp */
164 void udelay_masked (unsigned long usec)
170 if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
171 tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
172 tmo *= CONFIG_SYS_HZ; /* find number of "ticks" to wait to achieve target */
173 tmo /= 1000; /* finish normalize. */
174 } else { /* else small number, don't kill it prior to HZ multiply */
175 tmo = usec * CONFIG_SYS_HZ;
179 endtime = get_timer_masked () + tmo;
182 ulong now = get_timer_masked ();
183 diff = endtime - now;
188 * This function is derived from PowerPC code (read timebase as long long).
189 * On ARM it just returns the timer value.
191 unsigned long long get_ticks(void)
197 * This function is derived from PowerPC code (timebase clock frequency).
198 * On ARM it returns the number of timer ticks per second.
200 ulong get_tbclk (void)
204 tbclk = CONFIG_SYS_HZ;