1 files changed, 125 insertions, 0 deletions
diff --git a/arch/m68k/include/asm/delay.h b/arch/m68k/include/asm/delay.h
new file mode 100644
index 000000000..751712f8b
--- /dev/null
+++ b/arch/m68k/include/asm/delay.h
@@ -0,0 +1,125 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _M68K_DELAY_H
+#define _M68K_DELAY_H
+
+#include <asm/param.h>
+
+/*
+ * Copyright (C) 1994 Hamish Macdonald
+ * Copyright (C) 2004 Greg Ungerer <gerg@uclinux.com>
+ *
+ * Delay routines, using a pre-computed "loops_per_jiffy" value.
+ */
+
+#if defined(CONFIG_COLDFIRE)
+/*
+ * The ColdFire runs the delay 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 arbitrary 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.
+ */
+#define	DELAY_ALIGN	".balignw 4, 0x4a8e\n\t"
+#else
+/*
+ * No instruction alignment required for other m68k types.
+ */
+#define	DELAY_ALIGN
+#endif
+
+static inline void __delay(unsigned long loops)
+{
+	__asm__ __volatile__ (
+		DELAY_ALIGN
+		"1: subql #1,%0\n\t"
+		"jcc 1b"
+		: "=d" (loops)
+		: "0" (loops));
+}
+
+extern void __bad_udelay(void);
+
+
+#ifdef CONFIG_CPU_HAS_NO_MULDIV64
+/*
+ * The simpler m68k and ColdFire processors do not have a 32*32->64
+ * multiply instruction. So we need to handle them a little differently.
+ * We use a bit of shifting and a single 32*32->32 multiply to get close.
+ */
+#define	HZSCALE		(268435456 / (1000000 / HZ))
+
+#define	__const_udelay(u) \
+	__delay(((((u) * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6)
+
+#else
+
+static inline void __xdelay(unsigned long xloops)
+{
+	unsigned long tmp;
+
+	__asm__ ("mulul %2,%0:%1"
+		: "=d" (xloops), "=d" (tmp)
+		: "d" (xloops), "1" (loops_per_jiffy));
+	__delay(xloops * HZ);
+}
+
+/*
+ * The definition of __const_udelay is specifically made a macro so that
+ * the const factor (4295 = 2**32 / 1000000) can be optimized out when
+ * the delay is a const.
+ */
+#define	__const_udelay(n)	(__xdelay((n) * 4295))
+
+#endif
+
+static inline void __udelay(unsigned long usecs)
+{
+	__const_udelay(usecs);
+}
+
+/*
+ * 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)
+ */
+#define udelay(n) (__builtin_constant_p(n) ? \
+	((n) > 20000 ? __bad_udelay() : __const_udelay(n)) : __udelay(n))
+
+/*
+ * nanosecond delay:
+ *
+ * ((((HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6) is the number of loops
+ * per microsecond
+ *
+ * 1000 / ((((HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6) is the number of
+ * nanoseconds per loop
+ *
+ * So n / ( 1000 / ((((HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6) ) would
+ * be the number of loops for n nanoseconds
+ */
+
+/*
+ * The simpler m68k and ColdFire processors do not have a 32*32->64
+ * multiply instruction. So we need to handle them a little differently.
+ * We use a bit of shifting and a single 32*32->32 multiply to get close.
+ * This is a macro so that the const version can factor out the first
+ * multiply and shift.
+ */
+#define	HZSCALE		(268435456 / (1000000 / HZ))
+
+static inline void ndelay(unsigned long nsec)
+{
+	__delay(DIV_ROUND_UP(nsec *
+			     ((((HZSCALE) >> 11) *
+			       (loops_per_jiffy >> 11)) >> 6),
+			     1000));
+}
+#define ndelay(n) ndelay(n)
+
+#endif /* defined(_M68K_DELAY_H) */