source: SVN/rincon/u-boot/cpu/arm925t/interrupts.c @ 55

Last change on this file since 55 was 55, checked in by Tim Harvey, 22 months ago

rincon: added latest u-boot source

restored form server backup

Signed-off-by: Tim Harvey <tharvey@…>

File size: 4.9 KB
Line 
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
14 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
15 *
16 * See file CREDITS for list of people who contributed to this
17 * project.
18 *
19 * This program is free software; you can redistribute it and/or
20 * modify it under the terms of the GNU General Public License as
21 * published by the Free Software Foundation; either version 2 of
22 * the License, or (at your option) any later version.
23 *
24 * This program is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
27 * GNU General Public License for more details.
28 *
29 * You should have received a copy of the GNU General Public License
30 * along with this program; if not, write to the Free Software
31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
32 * MA 02111-1307 USA
33 */
34
35#include <common.h>
36#include <arm925t.h>
37#include <configs/omap1510.h>
38
39#define TIMER_LOAD_VAL 0xffffffff
40
41/* macro to read the 32 bit timer */
42#define READ_TIMER (*(volatile ulong *)(CFG_TIMERBASE+8))
43
44static ulong timestamp;
45static ulong lastdec;
46
47/* nothing really to do with interrupts, just starts up a counter. */
48int interrupt_init (void)
49{
50        int32_t val;
51
52        /* Start the decrementer ticking down from 0xffffffff */
53        *((int32_t *) (CFG_TIMERBASE + LOAD_TIM)) = TIMER_LOAD_VAL;
54        val = MPUTIM_ST | MPUTIM_AR | MPUTIM_CLOCK_ENABLE | (CFG_PVT << MPUTIM_PTV_BIT);
55        *((int32_t *) (CFG_TIMERBASE + CNTL_TIMER)) = val;
56
57        /* init the timestamp and lastdec value */
58        reset_timer_masked();
59
60        return (0);
61}
62
63/*
64 * timer without interrupts
65 */
66
67void reset_timer (void)
68{
69        reset_timer_masked ();
70}
71
72ulong get_timer (ulong base)
73{
74        return get_timer_masked () - base;
75}
76
77void set_timer (ulong t)
78{
79        timestamp = t;
80}
81
82/* delay x useconds AND preserve advance timestamp value */
83void udelay (unsigned long usec)
84{
85        ulong tmo, tmp;
86
87        if(usec >= 1000){               /* if "big" number, spread normalization to seconds */
88                tmo = usec / 1000;      /* start to normalize for usec to ticks per sec */
89                tmo *= CFG_HZ;          /* find number of "ticks" to wait to achieve target */
90                tmo /= 1000;            /* finish normalize. */
91        }else{                          /* else small number, don't kill it prior to HZ multiply */
92                tmo = usec * CFG_HZ;
93                tmo /= (1000*1000);
94        }
95
96        tmp = get_timer (0);            /* get current timestamp */
97        if( (tmo + tmp + 1) < tmp )     /* if setting this fordward will roll time stamp */
98                reset_timer_masked ();  /* reset "advancing" timestamp to 0, set lastdec value */
99        else
100                tmo += tmp;             /* else, set advancing stamp wake up time */
101
102        while (get_timer_masked () < tmo) /* loop till event */
103                /*NOP*/;
104}
105
106void reset_timer_masked (void)
107{
108        /* reset time */
109        lastdec = READ_TIMER;  /* capure current decrementer value time */
110        timestamp = 0;         /* start "advancing" time stamp from 0 */
111}
112
113ulong get_timer_masked (void)
114{
115        ulong now = READ_TIMER;         /* current tick value */
116
117        if (lastdec >= now) {           /* normal mode (non roll) */
118                /* normal mode */
119                timestamp += lastdec - now; /* move stamp fordward with absoulte diff ticks */
120        } else {                        /* we have overflow of the count down timer */
121                /* nts = ts + ld + (TLV - now)
122                 * ts=old stamp, ld=time that passed before passing through -1
123                 * (TLV-now) amount of time after passing though -1
124                 * nts = new "advancing time stamp"...it could also roll and cause problems.
125                 */
126                timestamp += lastdec + TIMER_LOAD_VAL - now;
127        }
128        lastdec = now;
129
130        return timestamp;
131}
132
133/* waits specified delay value and resets timestamp */
134void udelay_masked (unsigned long usec)
135{
136#ifdef CONFIG_INNOVATOROMAP1510
137        #define LOOPS_PER_MSEC 60 /* tuned on omap1510 */
138        volatile int i, time_remaining = LOOPS_PER_MSEC*usec;
139    for (i=time_remaining; i>0; i--) { }
140#else
141
142        ulong tmo;
143        ulong endtime;
144        signed long diff;
145
146        if (usec >= 1000) {             /* if "big" number, spread normalization to seconds */
147                tmo = usec / 1000;      /* start to normalize for usec to ticks per sec */
148                tmo *= CFG_HZ;          /* find number of "ticks" to wait to achieve target */
149                tmo /= 1000;            /* finish normalize. */
150        } else {                        /* else small number, don't kill it prior to HZ multiply */
151                tmo = usec * CFG_HZ;
152                tmo /= (1000*1000);
153        }
154
155        endtime = get_timer_masked () + tmo;
156
157        do {
158                ulong now = get_timer_masked ();
159                diff = endtime - now;
160        } while (diff >= 0);
161#endif
162}
163
164/*
165 * This function is derived from PowerPC code (read timebase as long long).
166 * On ARM it just returns the timer value.
167 */
168unsigned long long get_ticks(void)
169{
170        return get_timer(0);
171}
172
173/*
174 * This function is derived from PowerPC code (timebase clock frequency).
175 * On ARM it returns the number of timer ticks per second.
176 */
177ulong get_tbclk (void)
178{
179        ulong tbclk;
180
181        tbclk = CFG_HZ;
182        return tbclk;
183}
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