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Kirill Smelkov
linux
Commits
535f2150
Commit
535f2150
authored
Apr 17, 2003
by
Alan Cox
Committed by
Linus Torvalds
Apr 17, 2003
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[PATCH] generalise more PIT usage
parent
6dc51b6f
Changes
1
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1 changed file
with
14 additions
and
11 deletions
+14
-11
arch/i386/kernel/timers/timer_pit.c
arch/i386/kernel/timers/timer_pit.c
+14
-11
No files found.
arch/i386/kernel/timers/timer_pit.c
View file @
535f2150
...
...
@@ -16,6 +16,9 @@
extern
spinlock_t
i8259A_lock
;
extern
spinlock_t
i8253_lock
;
#include "do_timer.h"
#include "io_ports.h"
static
int
count_p
;
/* counter in get_offset_pit() */
static
int
__init
init_pit
(
char
*
override
)
{
...
...
@@ -23,6 +26,7 @@ static int __init init_pit(char* override)
if
(
override
[
0
]
&&
strncmp
(
override
,
"pit"
,
3
))
printk
(
KERN_ERR
"Warning: clock= override failed. Defaulting to PIT
\n
"
);
count_p
=
LATCH
;
return
0
;
}
...
...
@@ -86,7 +90,6 @@ static unsigned long get_offset_pit(void)
{
int
count
;
unsigned
long
flags
;
static
int
count_p
=
LATCH
;
/* for the first call after boot */
static
unsigned
long
jiffies_p
=
0
;
/*
...
...
@@ -96,9 +99,9 @@ static unsigned long get_offset_pit(void)
spin_lock_irqsave
(
&
i8253_lock
,
flags
);
/* timer count may underflow right here */
outb_p
(
0x00
,
0x43
);
/* latch the count ASAP */
outb_p
(
0x00
,
PIT_MODE
);
/* latch the count ASAP */
count
=
inb_p
(
0x4
0
);
/* read the latched count */
count
=
inb_p
(
PIT_CH
0
);
/* read the latched count */
/*
* We do this guaranteed double memory access instead of a _p
...
...
@@ -106,13 +109,13 @@ static unsigned long get_offset_pit(void)
*/
jiffies_t
=
jiffies
;
count
|=
inb_p
(
0x4
0
)
<<
8
;
count
|=
inb_p
(
PIT_CH
0
)
<<
8
;
/* VIA686a test code... reset the latch if count > max + 1 */
if
(
count
>
LATCH
)
{
outb_p
(
0x34
,
0x43
);
outb_p
(
LATCH
&
0xff
,
0x4
0
);
outb
(
LATCH
>>
8
,
0x4
0
);
outb_p
(
0x34
,
PIT_MODE
);
outb_p
(
LATCH
&
0xff
,
PIT_CH
0
);
outb
(
LATCH
>>
8
,
PIT_CH
0
);
count
=
LATCH
-
1
;
}
...
...
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