1 files changed, 45 insertions, 14 deletions

diff --git a/arch/um/sys-i386/delay.c b/arch/um/sys-i386/delay.c
index d623e074f41d..f3fe1a688f7e 100644
--- a/arch/um/sys-i386/delay.c
+++ b/arch/um/sys-i386/delay.c
@@ -1,29 +1,60 @@
+/*
+ * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
+ * Mostly copied from arch/x86/lib/delay.c
+ *
+ * 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/param.h>
 
-void __delay(unsigned long time)
+void __delay(unsigned long loops)
 {
-        /* Stolen from the i386 __loop_delay */
-        int d0;
-        __asm__ __volatile__(
-                "\tjmp 1f\n"
+        asm volatile(
+                "test %0,%0\n"
+                "jz 3f\n"
+                "jmp 1f\n"
+
                 ".align 16\n"
-                "1:\tjmp 2f\n"
+                "1: jmp 2f\n"
+
                 ".align 16\n"
-                "2:\tdecl %0\n\tjns 2b"
-                :"=&a" (d0)
-                :"0" (time));
+                "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)
 {
-        int 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);