1 files changed, 48 insertions, 0 deletions

diff --git a/arch/x86_64/lib/delay.c b/arch/x86_64/lib/delay.c
new file mode 100644
index 000000000000..6e2d66472eb1
--- /dev/null
+++ b/arch/x86_64/lib/delay.c
@@ -0,0 +1,48 @@
+/*
+ *      Precise Delay Loops for x86-64
+ *
+ *      Copyright (C) 1993 Linus Torvalds
+ *      Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ *
+ *      The __delay function must _NOT_ be inlined as its execution time
+ *      depends wildly on alignment on many x86 processors. 
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <asm/delay.h>
+
+#ifdef CONFIG_SMP
+#include <asm/smp.h>
+#endif
+
+int x86_udelay_tsc = 0;         /* Delay via TSC */
+
+void __delay(unsigned long loops)
+{
+        unsigned bclock, now;
+        
+        rdtscl(bclock);
+        do
+        {
+                rep_nop(); 
+                rdtscl(now);
+        }
+        while((now-bclock) < loops);
+}
+
+inline void __const_udelay(unsigned long xloops)
+{
+        __delay(((xloops * cpu_data[_smp_processor_id()].loops_per_jiffy) >> 32) * HZ);
+}
+
+void __udelay(unsigned long usecs)
+{
+        __const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
+}
+
+void __ndelay(unsigned long nsecs)
+{
+        __const_udelay(nsecs * 0x00005);  /* 2**32 / 1000000000 (rounded up) */
+}