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-rw-r--r--include/asm-powerpc/delay.h55
1 files changed, 55 insertions, 0 deletions
diff --git a/include/asm-powerpc/delay.h b/include/asm-powerpc/delay.h
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+++ 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 */