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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
* General purpose implementation of a simple periodic countdown timer.
*
* Copyright (c) 2007 CodeSourcery.
*
* This code is licenced under the GNU LGPL.
*/
#include "vl.h"
struct ptimer_state
{
int enabled; /* 0 = disabled, 1 = periodic, 2 = oneshot. */
uint64_t limit;
uint64_t delta;
uint32_t period_frac;
int64_t period;
int64_t last_event;
int64_t next_event;
QEMUBH *bh;
QEMUTimer *timer;
};
/* Use a bottom-half routine to avoid reentrancy issues. */
static void ptimer_trigger(ptimer_state *s)
{
if (s->bh) {
qemu_bh_schedule(s->bh);
}
}
static void ptimer_reload(ptimer_state *s)
{
if (s->delta == 0) {
ptimer_trigger(s);
s->delta = s->limit;
}
if (s->delta == 0 || s->period == 0) {
fprintf(stderr, "Timer with period zero, disabling\n");
s->enabled = 0;
return;
}
s->last_event = s->next_event;
s->next_event = s->last_event + s->delta * s->period;
if (s->period_frac) {
s->next_event += ((int64_t)s->period_frac * s->delta) >> 32;
}
qemu_mod_timer(s->timer, s->next_event);
}
static void ptimer_tick(void *opaque)
{
ptimer_state *s = (ptimer_state *)opaque;
ptimer_trigger(s);
s->delta = 0;
if (s->enabled == 2) {
s->enabled = 0;
} else {
ptimer_reload(s);
}
}
uint64_t ptimer_get_count(ptimer_state *s)
{
int64_t now;
uint64_t counter;
if (s->enabled) {
now = qemu_get_clock(vm_clock);
/* Figure out the current counter value. */
if (now - s->next_event > 0
|| s->period == 0) {
/* Prevent timer underflowing if it should already have
triggered. */
counter = 0;
} else {
uint64_t rem;
uint64_t div;
rem = s->next_event - now;
div = s->period;
counter = rem / div;
}
} else {
counter = s->delta;
}
return counter;
}
void ptimer_set_count(ptimer_state *s, uint64_t count)
{
s->delta = count;
if (s->enabled) {
s->next_event = qemu_get_clock(vm_clock);
ptimer_reload(s);
}
}
void ptimer_run(ptimer_state *s, int oneshot)
{
if (s->period == 0) {
fprintf(stderr, "Timer with period zero, disabling\n");
return;
}
s->enabled = oneshot ? 2 : 1;
s->next_event = qemu_get_clock(vm_clock);
ptimer_reload(s);
}
/* Pause a timer. Note that this may cause it to "lose" time, even if it
is immediately restarted. */
void ptimer_stop(ptimer_state *s)
{
if (!s->enabled)
return;
s->delta = ptimer_get_count(s);
qemu_del_timer(s->timer);
s->enabled = 0;
}
/* Set counter increment interval in nanoseconds. */
void ptimer_set_period(ptimer_state *s, int64_t period)
{
s->period = period;
s->period_frac = 0;
if (s->enabled) {
s->next_event = qemu_get_clock(vm_clock);
ptimer_reload(s);
}
}
/* Set counter frequency in Hz. */
void ptimer_set_freq(ptimer_state *s, uint32_t freq)
{
s->period = 1000000000ll / freq;
s->period_frac = (1000000000ll << 32) / freq;
if (s->enabled) {
s->next_event = qemu_get_clock(vm_clock);
ptimer_reload(s);
}
}
/* Set the initial countdown value. If reload is nonzero then also set
count = limit. */
void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload)
{
s->limit = limit;
if (reload)
s->delta = limit;
if (s->enabled) {
s->next_event = qemu_get_clock(vm_clock);
ptimer_reload(s);
}
}
void qemu_put_ptimer(QEMUFile *f, ptimer_state *s)
{
qemu_put_byte(f, s->enabled);
qemu_put_be64s(f, &s->limit);
qemu_put_be64s(f, &s->delta);
qemu_put_be32s(f, &s->period_frac);
qemu_put_be64s(f, &s->period);
qemu_put_be64s(f, &s->last_event);
qemu_put_be64s(f, &s->next_event);
qemu_put_timer(f, s->timer);
}
void qemu_get_ptimer(QEMUFile *f, ptimer_state *s)
{
s->enabled = qemu_get_byte(f);
qemu_get_be64s(f, &s->limit);
qemu_get_be64s(f, &s->delta);
qemu_get_be32s(f, &s->period_frac);
qemu_get_be64s(f, &s->period);
qemu_get_be64s(f, &s->last_event);
qemu_get_be64s(f, &s->next_event);
qemu_get_timer(f, s->timer);
}
ptimer_state *ptimer_init(QEMUBH *bh)
{
ptimer_state *s;
s = (ptimer_state *)qemu_mallocz(sizeof(ptimer_state));
s->bh = bh;
s->timer = qemu_new_timer(vm_clock, ptimer_tick, s);
return s;
}
|
