kernel-ark/include/linux/acpi_pmtmr.h
Thomas Gleixner d66bea57e7 [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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 08:13:58 -08:00

39 lines
635 B
C

#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