1 files changed, 76 insertions, 0 deletions
diff --git a/include/asm-m68knommu/delay.h b/include/asm-m68knommu/delay.h
new file mode 100644
index 0000000..e3a9762
--- /dev/null
+++ b/include/asm-m68knommu/delay.h
@@ -0,0 +1,76 @@
+#ifndef _M68KNOMMU_DELAY_H
+#define _M68KNOMMU_DELAY_H
+
+/*
+ * Copyright (C) 1994 Hamish Macdonald
+ * Copyright (C) 2004 Greg Ungerer <gerg@snapgear.com>
+ */
+
+#include <asm/param.h>
+
+extern __inline__ void __delay(unsigned long loops)
+{
+#if defined(CONFIG_COLDFIRE)
+	/* The coldfire runs this loop at significantly different speeds
+	 * depending upon long word alignment or not.  We'll pad it to
+	 * long word alignment which is the faster version.
+	 * The 0x4a8e is of course a 'tstl %fp' instruction.  This is better
+	 * than using a NOP (0x4e71) instruction because it executes in one
+	 * cycle not three and doesn't allow for an arbitary delay waiting
+	 * for bus cycles to finish.  Also fp/a6 isn't likely to cause a
+	 * stall waiting for the register to become valid if such is added
+	 * to the coldfire at some stage.
+	 */
+	__asm__ __volatile__ (	".balignw 4, 0x4a8e\n\t"
+				"1: subql #1, %0\n\t"
+				"jcc 1b"
+		: "=d" (loops) : "0" (loops));
+#else
+	__asm__ __volatile__ (	"1: subql #1, %0\n\t"
+				"jcc 1b"
+		: "=d" (loops) : "0" (loops));
+#endif
+}
+
+/*
+ *	Ideally we use a 32*32->64 multiply to calculate the number of
+ *	loop iterations, but the older standard 68k and ColdFire do not
+ *	have this instruction. So for them we have a clsoe approximation
+ *	loop using 32*32->32 multiplies only. This calculation based on
+ *	the ARM version of delay.
+ *
+ *	We want to implement:
+ *
+ *	loops = (usecs * 0x10c6 * HZ * loops_per_jiffy) / 2^32
+ */
+
+#define	HZSCALE		(268435456 / (1000000/HZ))
+
+extern unsigned long loops_per_jiffy;
+
+extern __inline__ void _udelay(unsigned long usecs)
+{
+#if defined(CONFIG_M68328) || defined(CONFIG_M68EZ328) || \
+    defined(CONFIG_M68VZ328) || defined(CONFIG_M68360) || \
+    defined(CONFIG_COLDFIRE)
+	__delay((((usecs * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6);
+#else
+	unsigned long tmp;
+
+	usecs *= 4295;		/* 2**32 / 1000000 */
+	__asm__ ("mulul %2,%0:%1"
+		: "=d" (usecs), "=d" (tmp)
+		: "d" (usecs), "1" (loops_per_jiffy*HZ));
+	__delay(usecs);
+#endif
+}
+
+/*
+ *	Moved the udelay() function into library code, no longer inlined.
+ *	I had to change the algorithm because we are overflowing now on
+ *	the faster ColdFire parts. The code is a little biger, so it makes
+ *	sense to library it.
+ */
+extern void udelay(unsigned long usecs);
+
+#endif /* defined(_M68KNOMMU_DELAY_H) */