[PATCH] Time: i386 Conversion - part 2: Rework TSC Support

As part of the i386 conversion to the generic timekeeping infrastructure, this
introduces a new tsc.c file.  The code in this file replaces the TSC
initialization, management and access code currently in timer_tsc.c (which
will be removed) that we want to preserve.

The code also introduces the following functionality:

o tsc_khz: like cpu_khz but stores the TSC frequency on systems that do not
  change TSC frequency w/ CPU frequency

o check/mark_tsc_unstable: accessor/modifier flag for TSC timekeeping
  usability

o minor cleanups to calibration math.

This patch also includes a one line __cpuinitdata fix from Zwane Mwaikambo.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 3b97a5eae9e8..a5f4f2aa007a 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -369,6 +369,11 @@ static void acpi_processor_idle(void)
                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
                 /* Get end time (ticks) */
                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
+
+#ifdef CONFIG_GENERIC_TIME
+                /* TSC halts in C2, so notify users */
+                mark_tsc_unstable();
+#endif
                 /* Re-enable interrupts */
                 local_irq_enable();
                 set_thread_flag(TIF_POLLING_NRFLAG);
@@ -409,6 +414,10 @@ static void acpi_processor_idle(void)
                                           ACPI_MTX_DO_NOT_LOCK);
                 }
 
+#ifdef CONFIG_GENERIC_TIME
+                /* TSC halts in C3, so notify users */
+                mark_tsc_unstable();
+#endif
                 /* Re-enable interrupts */
                 local_irq_enable();
                 set_thread_flag(TIF_POLLING_NRFLAG);