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
|
/*
* Precise Delay Loops for S390
*
* Copyright IBM Corp. 1999, 2008
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
* Heiko Carstens <heiko.carstens@de.ibm.com>,
*/
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/timex.h>
#include <linux/module.h>
#include <linux/irqflags.h>
#include <linux/interrupt.h>
#include <asm/vtimer.h>
#include <asm/div64.h>
void __delay(unsigned long loops)
{
/*
* To end the bloody studid and useless discussion about the
* BogoMips number I took the liberty to define the __delay
* function in a way that that resulting BogoMips number will
* yield the megahertz number of the cpu. The important function
* is udelay and that is done using the tod clock. -- martin.
*/
asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
}
static void __udelay_disabled(unsigned long long usecs)
{
unsigned long cr0, cr6, new;
u64 clock_saved, end;
end = get_tod_clock() + (usecs << 12);
clock_saved = local_tick_disable();
__ctl_store(cr0, 0, 0);
__ctl_store(cr6, 6, 6);
new = (cr0 & 0xffff00e0) | 0x00000800;
__ctl_load(new , 0, 0);
new = 0;
__ctl_load(new, 6, 6);
lockdep_off();
do {
set_clock_comparator(end);
vtime_stop_cpu();
local_irq_disable();
} while (get_tod_clock() < end);
lockdep_on();
__ctl_load(cr0, 0, 0);
__ctl_load(cr6, 6, 6);
local_tick_enable(clock_saved);
}
static void __udelay_enabled(unsigned long long usecs)
{
u64 clock_saved, end;
end = get_tod_clock() + (usecs << 12);
do {
clock_saved = 0;
if (end < S390_lowcore.clock_comparator) {
clock_saved = local_tick_disable();
set_clock_comparator(end);
}
vtime_stop_cpu();
local_irq_disable();
if (clock_saved)
local_tick_enable(clock_saved);
} while (get_tod_clock() < end);
}
/*
* Waits for 'usecs' microseconds using the TOD clock comparator.
*/
void __udelay(unsigned long long usecs)
{
unsigned long flags;
preempt_disable();
local_irq_save(flags);
if (in_irq()) {
__udelay_disabled(usecs);
goto out;
}
if (in_softirq()) {
if (raw_irqs_disabled_flags(flags))
__udelay_disabled(usecs);
else
__udelay_enabled(usecs);
goto out;
}
if (raw_irqs_disabled_flags(flags)) {
local_bh_disable();
__udelay_disabled(usecs);
_local_bh_enable();
goto out;
}
__udelay_enabled(usecs);
out:
local_irq_restore(flags);
preempt_enable();
}
EXPORT_SYMBOL(__udelay);
/*
* Simple udelay variant. To be used on startup and reboot
* when the interrupt handler isn't working.
*/
void udelay_simple(unsigned long long usecs)
{
u64 end;
end = get_tod_clock() + (usecs << 12);
while (get_tod_clock() < end)
cpu_relax();
}
void __ndelay(unsigned long long nsecs)
{
u64 end;
nsecs <<= 9;
do_div(nsecs, 125);
end = get_tod_clock() + nsecs;
if (nsecs & ~0xfffUL)
__udelay(nsecs >> 12);
while (get_tod_clock() < end)
barrier();
}
EXPORT_SYMBOL(__ndelay);
|
