um: clean up delay functions

Both sys-i386 and sys-x86_64 support now ndelay().  The delay functions
are based on arch/x86/lib/delay.c.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 42 insertions, 12 deletions

diff --git a/arch/um/sys-x86_64/delay.c b/arch/um/sys-x86_64/delay.c
index dee5be66da82..f3fe1a688f7e 100644
--- a/arch/um/sys-x86_64/delay.c
+++ b/arch/um/sys-x86_64/delay.c
@@ -1,30 +1,60 @@
 /*
- * Copyright 2003 PathScale, Inc.
- * Copied from arch/x86_64
+ * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
+ * Mostly copied from arch/x86/lib/delay.c
  *
- * Licensed under the GPL
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
  */
 
 #include <linux/module.h>
+#include <linux/kernel.h>
 #include <linux/delay.h>
-#include <asm/processor.h>
 #include <asm/param.h>
 
 void __delay(unsigned long loops)
 {
-        unsigned long i;
+        asm volatile(
+                "test %0,%0\n"
+                "jz 3f\n"
+                "jmp 1f\n"
 
-        for(i = 0; i < loops; i++)
-                cpu_relax();
+                ".align 16\n"
+                "1: jmp 2f\n"
+
+                ".align 16\n"
+                "2: dec %0\n"
+                " jnz 2b\n"
+                "3: dec %0\n"
+
+                : /* we don't need output */
+                : "a" (loops)
+        );
 }
+EXPORT_SYMBOL(__delay);
 
-void __udelay(unsigned long usecs)
+inline void __const_udelay(unsigned long xloops)
 {
-        unsigned long i, n;
+        int d0;
 
-        n = (loops_per_jiffy * HZ * usecs) / MILLION;
-        for(i=0;i<n;i++)
-                cpu_relax();
+        xloops *= 4;
+        asm("mull %%edx"
+                : "=d" (xloops), "=&a" (d0)
+                : "1" (xloops), "0"
+                (loops_per_jiffy * (HZ/4)));
+
+        __delay(++xloops);
 }
+EXPORT_SYMBOL(__const_udelay);
 
+void __udelay(unsigned long usecs)
+{
+        __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
+}
 EXPORT_SYMBOL(__udelay);
+
+void __ndelay(unsigned long nsecs)
+{
+        __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
+}
+EXPORT_SYMBOL(__ndelay);