blob: a57a46399faf63c735399e789c3fe2543cea5b70 (
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
62
63
64
65
66
67
|
/******************************************************************************
* Copyright (c) 2004, 2007 IBM Corporation
* All rights reserved.
* This program and the accompanying materials
* are made available under the terms of the BSD License
* which accompanies this distribution, and is available at
* http://www.opensource.org/licenses/bsd-license.php
*
* Contributors:
* IBM Corporation - initial implementation
*****************************************************************************/
#include <types.h>
//*******************************************************************
// variable "tb_freq" contains the frequency in Hz
// and is read from the device tree (setup by LLFW) in "init.c"
uint64_t tb_freq;
//-------------------------------------------------------------------
// Read the current timebase
uint64_t get_time(void)
{
uint64_t act;
__asm__ __volatile__(
"0: mftbu %0 ;\
mftbl %%r0 ; \
mftbu %%r4 ; \
cmpw %0,%%r4 ; \
bne 0b; \
sldi %0,%0,32; \
or %0,%0,%%r0"
: "=r"(act)
: /* no inputs */
: "r0", "r4");
return act;
}
//-------------------------------------------------------------------
// wait for ticks/scale timebase ticks
void wait_ticks(uint64_t ticks)
{
uint64_t timeout = get_time() + ticks;
while (get_time() < timeout) {
unsigned int i;
for (i = 1000; i > 0; i--)
__asm__ __volatile__ ("" : : : "memory");
}
}
//-------------------------------------------------------------------
// wait for (at least) usecs microseconds
void udelay(unsigned int usecs)
{
// first multiply the usec with timebase and then devide
// because 1.000.000 is relatively huge compared to usecs
wait_ticks((usecs*tb_freq)/1000000);
}
//-------------------------------------------------------------------
// wait for (at least) msecs milliseconds
void mdelay(unsigned int msecs)
{
// first multiply the msec and timebase and then devide
// because 1.000 is relatively huge compared to msecs
wait_ticks((msecs*tb_freq)/1000);
}
|
