[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>

arch/i386/kernel/timers/common.c

@@ -6,6 +6,7 @@
 #include <linux/timex.h>
 #include <linux/errno.h>
 #include <linux/jiffies.h>
+#include <linux/module.h>
 
 #include <asm/io.h>
 #include <asm/timer.h>
@@ -24,7 +25,7 @@
 
 #define CALIBRATE_TIME	(5 * 1000020/HZ)
 
-unsigned long __init calibrate_tsc(void)
+unsigned long calibrate_tsc(void)
 {
 	mach_prepare_counter();
 
@@ -139,7 +140,7 @@ unsigned long __init calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr)
 #endif
 
 /* calculate cpu_khz */
-void __init init_cpu_khz(void)
+void init_cpu_khz(void)
 {
 	if (cpu_has_tsc) {
 		unsigned long tsc_quotient = calibrate_tsc();
@@ -158,3 +159,4 @@ void __init init_cpu_khz(void)
 		}
 	}
 }
+

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;

include/asm-i386/timer.h

@@ -53,6 +53,7 @@ extern struct init_timer_opts timer_cyclone_init;
 
 extern unsigned long calibrate_tsc(void);
 extern void init_cpu_khz(void);
+extern int recalibrate_cpu_khz(void);
 #ifdef CONFIG_HPET_TIMER
 extern struct init_timer_opts timer_hpet_init;
 extern unsigned long calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr);