1 files changed, 44 insertions, 0 deletions

diff --git a/arch/arm/include/asm/delay.h b/arch/arm/include/asm/delay.h
new file mode 100644
index 00000000000..b2deda18154
--- /dev/null
+++ b/arch/arm/include/asm/delay.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 1995-2004 Russell King
+ *
+ * Delay routines, using a pre-computed "loops_per_second" value.
+ */
+#ifndef __ASM_ARM_DELAY_H
+#define __ASM_ARM_DELAY_H
+
+#include <asm/param.h>  /* HZ */
+
+extern void __delay(int loops);
+
+/*
+ * This function intentionally does not exist; if you see references to
+ * it, it means that you're calling udelay() with an out of range value.
+ *
+ * With currently imposed limits, this means that we support a max delay
+ * of 2000us. Further limits: HZ<=1000 and bogomips<=3355
+ */
+extern void __bad_udelay(void);
+
+/*
+ * division by multiplication: you don't have to worry about
+ * loss of precision.
+ *
+ * Use only for very small delays ( < 1 msec).  Should probably use a
+ * lookup table, really, as the multiplications take much too long with
+ * short delays.  This is a "reasonable" implementation, though (and the
+ * first constant multiplications gets optimized away if the delay is
+ * a constant)
+ */
+extern void __udelay(unsigned long usecs);
+extern void __const_udelay(unsigned long);
+
+#define MAX_UDELAY_MS 2
+
+#define udelay(n)                                                       \
+        (__builtin_constant_p(n) ?                                      \
+          ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() :              \
+                        __const_udelay((n) * ((2199023U*HZ)>>11))) :    \
+          __udelay(n))
+
+#endif /* defined(_ARM_DELAY_H) */
+