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Commit d66bea57 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
Browse files

[PATCH] Allow early access to the power management timer 



Allow early access to the power management timer by exposing the verified read
function and providing a helper function which checks the pmtmr_ioport
variable and returns either the pm timer readout or 0 in case the pm timer is
not available.

Create a new header file and replace also the ifdef'ed extern definition in
arch/i386/kernel/acpi/boot.c

This is a preperatory patch for the rework of the local apic timer
calibration.

No functional changes.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 169a0abb

arch/i386/kernel/acpi/boot.c

+1 −4
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#include <linux/init.h>

#include <linux/acpi.h>

#include <linux/acpi_pmtmr.h>

#include <linux/efi.h>

#include <linux/cpumask.h>

#include <linux/module.h>
@@ -676,10 +677,6 @@ static int __init acpi_parse_hpet(struct acpi_table_header *table) 
#define	acpi_parse_hpet	NULL

#endif



#ifdef CONFIG_X86_PM_TIMER

extern u32 pmtmr_ioport;

#endif



static int __init acpi_parse_fadt(struct acpi_table_header *table)

{

drivers/clocksource/acpi_pm.c

+9 −8
Original line number Diff line number Diff line
@@ -16,15 +16,13 @@ 
 * This file is licensed under the GPL v2.

 */



#include <linux/acpi_pmtmr.h>

#include <linux/clocksource.h>

#include <linux/errno.h>

#include <linux/init.h>

#include <linux/pci.h>

#include <asm/io.h>



/* Number of PMTMR ticks expected during calibration run */

#define PMTMR_TICKS_PER_SEC 3579545



/*

 * The I/O port the PMTMR resides at.

 * The location is detected during setup_arch(),
@@ -32,15 +30,13 @@ 
 */

u32 pmtmr_ioport __read_mostly;



#define ACPI_PM_MASK CLOCKSOURCE_MASK(24) /* limit it to 24 bits */



static inline u32 read_pmtmr(void)

{

	/* mask the output to 24 bits */

	return inl(pmtmr_ioport) & ACPI_PM_MASK;

}



static cycle_t acpi_pm_read_verified(void)

u32 acpi_pm_read_verified(void)

{

	u32 v1 = 0, v2 = 0, v3 = 0;
@@ -57,7 +53,12 @@ static cycle_t acpi_pm_read_verified(void) 
	} while (unlikely((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)

			  || (v3 > v1 && v3 < v2)));



	return (cycle_t)v2;

	return v2;

}



static cycle_t acpi_pm_read_slow(void)

{

	return (cycle_t)acpi_pm_read_verified();

}



static cycle_t acpi_pm_read(void)
@@ -88,7 +89,7 @@ __setup("acpi_pm_good", acpi_pm_good_setup); 


static inline void acpi_pm_need_workaround(void)

{

	clocksource_acpi_pm.read = acpi_pm_read_verified;

	clocksource_acpi_pm.read = acpi_pm_read_slow;

	clocksource_acpi_pm.rating = 110;

}

include/linux/acpi_pmtmr.h

0 → 100644
+38 −0
Original line number Diff line number Diff line 
#ifndef _ACPI_PMTMR_H_

#define _ACPI_PMTMR_H_



#include <linux/clocksource.h>



/* Number of PMTMR ticks expected during calibration run */

#define PMTMR_TICKS_PER_SEC 3579545



/* limit it to 24 bits */

#define ACPI_PM_MASK CLOCKSOURCE_MASK(24)



/* Overrun value */

#define ACPI_PM_OVRRUN	(1<<24)



#ifdef CONFIG_X86_PM_TIMER



extern u32 acpi_pm_read_verified(void);

extern u32 pmtmr_ioport;



static inline u32 acpi_pm_read_early(void)

{

	if (!pmtmr_ioport)

		return 0;

	/* mask the output to 24 bits */

	return acpi_pm_read_verified() & ACPI_PM_MASK;

}



#else



static inline u32 acpi_pm_read_early(void)

{

	return 0;

}



#endif



#endif