blob: 6d2fee8eba5276a6377717783bc0d0fa462acb0f (
plain)
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
|
#include <common.h>
#include <init.h>
#include <efi.h>
#include <efi/efi.h>
#include <clock.h>
#ifdef __x86_64__
uint64_t ticks_read(void)
{
uint64_t a, d;
__asm__ volatile ("rdtsc" : "=a" (a), "=d" (d));
return (d << 32) | a;
}
#else
uint64_t ticks_read(void)
{
uint64_t val;
__asm__ volatile ("rdtsc" : "=A" (val));
return val;
}
#endif
static uint64_t freq;
/* count TSC ticks during a millisecond delay */
static uint64_t ticks_freq(void)
{
uint64_t ticks_start, ticks_end;
ticks_start = ticks_read();
BS->stall(1000);
ticks_end = ticks_read();
return (ticks_end - ticks_start) * 1000;
}
static uint64_t efi_clocksource_read(void)
{
return 1000 * 1000 * ticks_read() / freq;
}
static struct clocksource cs = {
.read = efi_clocksource_read,
.mask = CLOCKSOURCE_MASK(64),
.shift = 0,
};
static int efi_clocksource_init(void)
{
cs.mult = clocksource_hz2mult(1000 * 1000, cs.shift);
freq = ticks_freq();
return init_clock(&cs);
}
/* for efi the time must be init at core initcall level */
core_initcall(efi_clocksource_init);
|
