1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/* Periodic Interval Timer Implementation for OpenPCD
* (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* TODO: handle jiffies wrap correctly!
*/
#include <errno.h>
#include <sys/types.h>
#include <asm/system.h>
#include <lib_AT91SAM7.h>
#include <AT91SAM7.h>
#include <os/pit.h>
#include <os/dbgu.h>
#include <os/system_irq.h>
#include "../openpcd.h"
/* PIT runs at MCK/16 (= 3MHz) */
#define PIV_MS(x) (x * 3000)
static struct timer_list *timers;
volatile unsigned long jiffies;
static void __timer_insert(struct timer_list *new)
{
struct timer_list *tl, *tl_prev = NULL;
if (!timers) {
/* optimize for the common, fast case */
new->next = NULL;
timers = new;
return;
}
for (tl = timers; tl != NULL; tl = tl->next) {
if (tl->expires < new->expires) {
/* we need ot add just before this one */
if (!tl_prev) {
new->next = timers;
timers = new;
} else {
new->next = tl;
tl_prev->next = new;
}
}
tl_prev = tl;
}
}
static int __timer_remove(struct timer_list *old)
{
struct timer_list *tl, *tl_prev = NULL;
for (tl = timers; tl != NULL; tl = tl->next) {
if (tl == old) {
if (tl == timers)
timers = tl->next;
else
tl_prev->next = tl->next;
return 1;
}
tl_prev = tl;
}
return 0;
}
int timer_del(struct timer_list *tl)
{
unsigned long flags;
int ret;
local_irq_save(flags);
ret = __timer_remove(tl);
local_irq_restore(flags);
return ret;
}
void timer_add(struct timer_list *tl)
{
unsigned long flags;
local_irq_save(flags);
__timer_insert(tl);
local_irq_restore(flags);
}
static void pit_irq(u_int32_t sr)
{
struct timer_list *tl, *next;
if (!(sr & 0x1))
return;
jiffies += *AT91C_PITC_PIVR >> 20;
/* this is the most simple/stupid algorithm one can come up with, but
* hey, we're on a small embedded platform with only a hand ful
* of timers, at all */
for (tl = timers; tl != NULL; tl = next) {
next = tl->next;
if (tl->expires <= jiffies) {
/* delete timer from list */
timer_del(tl);
tl->function(tl->data);
}
}
}
void pit_mdelay(u_int32_t ms)
{
u_int32_t end;
end = (AT91F_PITGetPIIR(AT91C_BASE_PITC) + ms) % 20;
while (end < AT91F_PITGetPIIR(AT91C_BASE_PITC)) { }
}
void mdelay(u_int32_t ms)
{
return pit_mdelay(ms);
}
void usleep(u_int32_t us)
{
return;
return pit_mdelay(us/1000);
}
void pit_init(void)
{
AT91F_PITC_CfgPMC();
AT91F_PITInit(AT91C_BASE_PITC, 1000000/HZ /* uS */, 48 /* MHz */);
sysirq_register(AT91SAM7_SYSIRQ_PIT, &pit_irq);
AT91F_PITEnableInt(AT91C_BASE_PITC);
}
|
