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Commit c5d28fb2 authored by Dave Jones's avatar Dave Jones
Browse files

[CPUFREQ] Recalibrate cpu_khz [2/2] 



Some cpufreq drivers (at that time, only powernow-k7) need to recalibrate the
cpu_khz at runtime.

Signed-off-by: default avatarBruno Ducrot <ducrot@poupinou.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 91350ed4

arch/i386/kernel/timers/common.c

+4 −2
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/timex.h>

#include <linux/errno.h>

#include <linux/jiffies.h>

#include <linux/module.h>



#include <asm/io.h>

#include <asm/timer.h>
@@ -24,7 +25,7 @@ 


#define CALIBRATE_TIME	(5 * 1000020/HZ)



unsigned long __init calibrate_tsc(void)

unsigned long calibrate_tsc(void)

{

	mach_prepare_counter();
@@ -139,7 +140,7 @@ bad_calibration: 
#endif



/* calculate cpu_khz */

void __init init_cpu_khz(void)

void init_cpu_khz(void)

{

	if (cpu_has_tsc) {

		unsigned long tsc_quotient = calibrate_tsc();
@@ -158,3 +159,4 @@ void __init init_cpu_khz(void) 
		}

	}

}

arch/i386/kernel/timers/timer_tsc.c

+20 −0
Original line number Diff line number Diff line
@@ -320,6 +320,26 @@ core_initcall(cpufreq_tsc); 
static inline void cpufreq_delayed_get(void) { return; }

#endif 



int recalibrate_cpu_khz(void)

{

#ifndef CONFIG_SMP

	unsigned long cpu_khz_old = cpu_khz;



	if (cpu_has_tsc) {

		init_cpu_khz();

		cpu_data[0].loops_per_jiffy =

		    cpufreq_scale(cpu_data[0].loops_per_jiffy,

			          cpu_khz_old,

				  cpu_khz);

		return 0;

	} else

		return -ENODEV;

#else

	return -ENODEV;

#endif

}

EXPORT_SYMBOL(recalibrate_cpu_khz);



static void mark_offset_tsc(void)

{

	unsigned long lost,delay;

include/asm-i386/timer.h

+1 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ extern struct init_timer_opts timer_cyclone_init; 


extern unsigned long calibrate_tsc(void);

extern void init_cpu_khz(void);

extern int recalibrate_cpu_khz(void);

#ifdef CONFIG_HPET_TIMER

extern struct init_timer_opts timer_hpet_init;

extern unsigned long calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr);