source: SVN/rincon/u-boot/cpu/at32ap/interrupts.c @ 55

Last change on this file since 55 was 55, checked in by Tim Harvey, 2 years ago

rincon: added latest u-boot source

restored form server backup

Signed-off-by: Tim Harvey <tharvey@…>

File size: 3.4 KB
Line 
1/*
2 * Copyright (C) 2004-2006 Atmel Corporation
3 *
4 * See file CREDITS for list of people who contributed to this
5 * project.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
20 * MA 02111-1307 USA
21 */
22#include <common.h>
23#include <div64.h>
24
25#include <asm/errno.h>
26#include <asm/io.h>
27#include <asm/processor.h>
28#include <asm/sysreg.h>
29
30#include <asm/arch/memory-map.h>
31
32#define HANDLER_MASK    0x00ffffff
33#define INTLEV_SHIFT    30
34#define INTLEV_MASK     0x00000003
35
36DECLARE_GLOBAL_DATA_PTR;
37
38/* Incremented whenever COUNT reaches 0xffffffff by timer_interrupt_handler */
39volatile unsigned long timer_overflow;
40
41/*
42 * Instead of dividing by get_tbclk(), multiply by this constant and
43 * right-shift the result by 32 bits.
44 */
45static unsigned long tb_factor;
46
47unsigned long get_tbclk(void)
48{
49        return gd->cpu_hz;
50}
51
52unsigned long long get_ticks(void)
53{
54        unsigned long lo, hi_now, hi_prev;
55
56        do {
57                hi_prev = timer_overflow;
58                lo = sysreg_read(COUNT);
59                hi_now = timer_overflow;
60        } while (hi_prev != hi_now);
61
62        return ((unsigned long long)hi_now << 32) | lo;
63}
64
65void reset_timer(void)
66{
67        sysreg_write(COUNT, 0);
68        cpu_sync_pipeline();    /* process any pending interrupts */
69        timer_overflow = 0;
70}
71
72unsigned long get_timer(unsigned long base)
73{
74        u64 now = get_ticks();
75
76        now *= tb_factor;
77        return (unsigned long)(now >> 32) - base;
78}
79
80void set_timer(unsigned long t)
81{
82        unsigned long long ticks = t;
83        unsigned long lo, hi, hi_new;
84
85        ticks = (ticks * get_tbclk()) / CFG_HZ;
86        hi = ticks >> 32;
87        lo = ticks & 0xffffffffUL;
88
89        do {
90                timer_overflow = hi;
91                sysreg_write(COUNT, lo);
92                hi_new = timer_overflow;
93        } while (hi_new != hi);
94}
95
96/*
97 * For short delays only. It will overflow after a few seconds.
98 */
99void udelay(unsigned long usec)
100{
101        unsigned long cycles;
102        unsigned long base;
103        unsigned long now;
104
105        base = sysreg_read(COUNT);
106        cycles = ((usec * (get_tbclk() / 10000)) + 50) / 100;
107
108        do {
109                now = sysreg_read(COUNT);
110        } while ((now - base) < cycles);
111}
112
113static int set_interrupt_handler(unsigned int nr, void (*handler)(void),
114                                 unsigned int priority)
115{
116        extern void _evba(void);
117        unsigned long intpr;
118        unsigned long handler_addr = (unsigned long)handler;
119
120        handler_addr -= (unsigned long)&_evba;
121
122        if ((handler_addr & HANDLER_MASK) != handler_addr
123            || (priority & INTLEV_MASK) != priority)
124                return -EINVAL;
125
126        intpr = (handler_addr & HANDLER_MASK);
127        intpr |= (priority & INTLEV_MASK) << INTLEV_SHIFT;
128        writel(intpr, (void *)INTC_BASE + 4 * nr);
129
130        return 0;
131}
132
133void timer_init(void)
134{
135        extern void timer_interrupt_handler(void);
136        u64 tmp;
137
138        sysreg_write(COUNT, 0);
139
140        tmp = (u64)CFG_HZ << 32;
141        tmp += gd->cpu_hz / 2;
142        do_div(tmp, gd->cpu_hz);
143        tb_factor = (u32)tmp;
144
145        if (set_interrupt_handler(0, &timer_interrupt_handler, 3))
146                return;
147
148        /* For all practical purposes, this gives us an overflow interrupt */
149        sysreg_write(COMPARE, 0xffffffff);
150}
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