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Kirill Smelkov
linux
Commits
abb2ed85
Commit
abb2ed85
authored
Apr 17, 2003
by
Alan Cox
Committed by
Linus Torvalds
Apr 17, 2003
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[PATCH] generalise PIT usage in tsc code, plus tsc sync
parent
535f2150
Changes
1
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1 changed file
with
13 additions
and
24 deletions
+13
-24
arch/i386/kernel/timers/timer_tsc.c
arch/i386/kernel/timers/timer_tsc.c
+13
-24
No files found.
arch/i386/kernel/timers/timer_tsc.c
View file @
abb2ed85
...
...
@@ -15,6 +15,9 @@
/* processor.h for distable_tsc flag */
#include <asm/processor.h>
#include "io_ports.h"
#include "mach_timer.h"
int
tsc_disable
__initdata
=
0
;
extern
spinlock_t
i8253_lock
;
...
...
@@ -57,6 +60,8 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc)
}
static
int
count2
;
/* counter for mark_offset_tsc() */
/* Cached *multiplier* to convert TSC counts to microseconds.
* (see the equation below).
* Equal to 2^32 * (1 / (clocks per usec) ).
...
...
@@ -114,7 +119,7 @@ static void mark_offset_tsc(void)
{
int
count
;
int
countmp
;
static
int
count1
=
0
,
count2
=
LATCH
;
static
int
count1
=
0
;
unsigned
long
long
this_offset
,
last_offset
;
write_lock
(
&
monotonic_lock
);
...
...
@@ -136,10 +141,10 @@ static void mark_offset_tsc(void)
rdtsc
(
last_tsc_low
,
last_tsc_high
);
spin_lock
(
&
i8253_lock
);
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
(
0x4
0
)
<<
8
;
count
=
inb_p
(
PIT_CH
0
);
/* read the latched count */
count
|=
inb
(
PIT_CH
0
)
<<
8
;
spin_unlock
(
&
i8253_lock
);
if
(
pit_latch_buggy
)
{
...
...
@@ -187,26 +192,11 @@ static void delay_tsc(unsigned long loops)
* device.
*/
#define CALIBRATE_LATCH (5 * LATCH)
#define CALIBRATE_TIME (5 * 1000020/HZ)
unsigned
long
__init
calibrate_tsc
(
void
)
{
/* Set the Gate high, disable speaker */
outb
((
inb
(
0x61
)
&
~
0x02
)
|
0x01
,
0x61
);
/*
* Now let's take care of CTC channel 2
*
* Set the Gate high, program CTC channel 2 for mode 0,
* (interrupt on terminal count mode), binary count,
* load 5 * LATCH count, (LSB and MSB) to begin countdown.
*
* Some devices need a delay here.
*/
outb
(
0xb0
,
0x43
);
/* binary, mode 0, LSB/MSB, Ch 2 */
outb_p
(
CALIBRATE_LATCH
&
0xff
,
0x42
);
/* LSB of count */
outb_p
(
CALIBRATE_LATCH
>>
8
,
0x42
);
/* MSB of count */
mach_prepare_counter
();
{
unsigned
long
startlow
,
starthigh
;
...
...
@@ -214,10 +204,7 @@ unsigned long __init calibrate_tsc(void)
unsigned
long
count
;
rdtsc
(
startlow
,
starthigh
);
count
=
0
;
do
{
count
++
;
}
while
((
inb
(
0x61
)
&
0x20
)
==
0
);
mach_countup
(
&
count
);
rdtsc
(
endlow
,
endhigh
);
last_tsc_low
=
endlow
;
...
...
@@ -340,6 +327,8 @@ static int __init init_tsc(char* override)
cpufreq_register_notifier
(
&
time_cpufreq_notifier_block
,
CPUFREQ_TRANSITION_NOTIFIER
);
#endif
count2
=
LATCH
;
/* initialize counter for mark_offset_tsc() */
if
(
cpu_has_tsc
)
{
unsigned
long
tsc_quotient
=
calibrate_tsc
();
if
(
tsc_quotient
)
{
...
...
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