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Date: Wed, 1 Jun 2011 16:18:44 +0200
From: Richard Weinberger <richard@....at>
To: linux-kernel@...r.kernel.org
Cc: user-mode-linux-devel@...ts.sourceforge.net,
Richard Weinberger <richard@....at>
Subject: [PATCH 2/2] 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@....at>
---
arch/um/include/asm/delay.h | 8 +----
arch/um/sys-i386/delay.c | 63 ++++++++++++++++++++++++++++++++-----------
arch/um/sys-x86_64/delay.c | 54 ++++++++++++++++++++++++++++--------
3 files changed, 91 insertions(+), 34 deletions(-)
diff --git a/arch/um/include/asm/delay.h b/arch/um/include/asm/delay.h
index c71e32b..1094519 100644
--- a/arch/um/include/asm/delay.h
+++ b/arch/um/include/asm/delay.h
@@ -1,8 +1,6 @@
#ifndef __UM_DELAY_H
#define __UM_DELAY_H
-#define MILLION 1000000
-
/* Undefined on purpose */
extern void __bad_udelay(void);
@@ -12,9 +10,7 @@ extern void __delay(unsigned long loops);
#define udelay(n) ((__builtin_constant_p(n) && (n) > 20000) ? \
__bad_udelay() : __udelay(n))
-/* It appears that ndelay is not used at all for UML, and has never been
- * implemented. */
-extern void __unimplemented_ndelay(void);
-#define ndelay(n) __unimplemented_ndelay()
+#define ndelay(n) ((__builtin_constant_p(n) && (n) > 20000) ? \
+ __bad_udelay() : __ndelay(n))
#endif
diff --git a/arch/um/sys-i386/delay.c b/arch/um/sys-i386/delay.c
index d623e07..65851ce 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@....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"
- ".align 16\n"
- "1:\tjmp 2f\n"
- ".align 16\n"
- "2:\tdecl %0\n\tjns 2b"
- :"=&a" (d0)
- :"0" (time));
+ asm volatile(
+ " test %0,%0 \n"
+ " jz 3f \n"
+ " jmp 1f \n"
+
+ ".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)
{
- 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);
diff --git a/arch/um/sys-x86_64/delay.c b/arch/um/sys-x86_64/delay.c
index dee5be6..65851ce 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@....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);
--
1.7.5.3
--
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