[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: Bruno Ducrot <ducrot@poupinou.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
index 7926d967be00..180444d87824 100644
--- a/arch/i386/kernel/timers/timer_tsc.c
+++ b/arch/i386/kernel/timers/timer_tsc.c
@@ -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;