x86/timers: Move the simple udelay calibration to tsc.h

Commit dd759d93f4dd ("x86/timers: Add simple udelay calibration") adds
an static function in x86 boot-time initializations.

But, this function is actually related to TSC, so it should be maintained
in tsc.c, not in setup.c.

Move simple_udelay_calibration() from setup.c to tsc.c and rename it to
tsc_early_delay_calibrate for more readability.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1500003247-17368-1-git-send-email-douly.fnst@cn.fujitsu.com

arch/x86/include/asm/tsc.h

@@ -31,6 +31,7 @@ static inline cycles_t get_cycles(void)
 
 extern struct system_counterval_t convert_art_to_tsc(u64 art);
 
+extern void tsc_early_delay_calibrate(void);
 extern void tsc_init(void);
 extern void mark_tsc_unstable(char *reason);
 extern int unsynchronized_tsc(void);

arch/x86/kernel/setup.c

@@ -822,26 +822,6 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
 	return 0;
 }
 
-static void __init simple_udelay_calibration(void)
-{
-	unsigned int tsc_khz, cpu_khz;
-	unsigned long lpj;
-
-	if (!boot_cpu_has(X86_FEATURE_TSC))
-		return;
-
-	cpu_khz = x86_platform.calibrate_cpu();
-	tsc_khz = x86_platform.calibrate_tsc();
-
-	tsc_khz = tsc_khz ? : cpu_khz;
-	if (!tsc_khz)
-		return;
-
-	lpj = tsc_khz * 1000;
-	do_div(lpj, HZ);
-	loops_per_jiffy = lpj;
-}
-
 /*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
@@ -1049,7 +1029,7 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	init_hypervisor_platform();
 
-	simple_udelay_calibration();
+	tsc_early_delay_calibrate();
 
 	x86_init.resources.probe_roms();
 

arch/x86/kernel/tsc.c

@@ -1263,6 +1263,25 @@ static int __init init_tsc_clocksource(void)
  */
 device_initcall(init_tsc_clocksource);
 
+void __init tsc_early_delay_calibrate(void)
+{
+	unsigned long lpj;
+
+	if (!boot_cpu_has(X86_FEATURE_TSC))
+		return;
+
+	cpu_khz = x86_platform.calibrate_cpu();
+	tsc_khz = x86_platform.calibrate_tsc();
+
+	tsc_khz = tsc_khz ? : cpu_khz;
+	if (!tsc_khz)
+		return;
+
+	lpj = tsc_khz * 1000;
+	do_div(lpj, HZ);
+	loops_per_jiffy = lpj;
+}
+
 void __init tsc_init(void)
 {
 	u64 lpj, cyc;