[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>
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index e94aff6..56818cf 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -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 @@
#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)
{
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index c7276a6..ccaa6a3 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -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 @@
} 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 @@
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;
}
diff --git a/include/linux/acpi_pmtmr.h b/include/linux/acpi_pmtmr.h
new file mode 100644
index 0000000..1d0ef1a
--- /dev/null
+++ b/include/linux/acpi_pmtmr.h
@@ -0,0 +1,38 @@
+#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
+