1 files changed, 55 insertions, 0 deletions

diff --git a/include/asm-powerpc/delay.h b/include/asm-powerpc/delay.h
new file mode 100644
index 000000000000..1492aa9ab716
--- /dev/null
+++ b/include/asm-powerpc/delay.h
@@ -0,0 +1,55 @@
+#ifndef _ASM_POWERPC_DELAY_H
+#define _ASM_POWERPC_DELAY_H
+
+/*
+ * Copyright 1996, Paul Mackerras.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan,
+ * Anton Blanchard.
+ */
+
+extern unsigned long tb_ticks_per_usec;
+
+#ifdef CONFIG_PPC64
+/* define these here to prevent circular dependencies */
+/* these instructions control the thread priority on multi-threaded cpus */
+#define __HMT_low()     asm volatile("or 1,1,1")
+#define __HMT_medium()  asm volatile("or 2,2,2")
+#else
+#define __HMT_low()
+#define __HMT_medium()
+#endif
+
+#define __barrier()     asm volatile("" ::: "memory")
+
+static inline unsigned long __get_tb(void)
+{
+        unsigned long rval;
+
+        asm volatile("mftb %0" : "=r" (rval));
+        return rval;
+}
+
+static inline void __delay(unsigned long loops)
+{
+        unsigned long start = __get_tb();
+
+        while((__get_tb() - start) < loops)
+                __HMT_low();
+        __HMT_medium();
+        __barrier();
+}
+
+static inline void udelay(unsigned long usecs)
+{
+        unsigned long loops = tb_ticks_per_usec * usecs;
+
+        __delay(loops);
+}
+
+#endif /* _ASM_POWERPC_DELAY_H */