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authorLinus Torvalds <torvalds@linux-foundation.org>2009-06-08 09:22:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-08 09:22:53 -0700
commit46056be71c37378f518711da651e4bb76d650ee9 (patch)
tree63c563bc3b84f22b517114ebb101b991958228a4 /arch/mips/lib/delay.c
parent5284c6b99ea017f73c09b50f34a637ff9d5d26a0 (diff)
parent5636919b5c909fee54a6ef5226475ecae012ad02 (diff)
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Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: MIPS: Outline udelay and fix a few issues. MIPS: ioctl.h: Fix headers_check warnings MIPS: Cobalt: PCI bus is always required to obtain the board ID MIPS: Kconfig: Remove "Support for" from Cavium system type MIPS: Sibyte: Honor CONFIG_CMDLINE SSB: BCM47xx: Export ssb_watchdog_timer_set
Diffstat (limited to 'arch/mips/lib/delay.c')
-rw-r--r--arch/mips/lib/delay.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/arch/mips/lib/delay.c b/arch/mips/lib/delay.c
new file mode 100644
index 00000000000..f69c6b569eb
--- /dev/null
+++ b/arch/mips/lib/delay.c
@@ -0,0 +1,56 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994 by Waldorf Electronics
+ * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2007 Maciej W. Rozycki
+ */
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/smp.h>
+
+#include <asm/compiler.h>
+#include <asm/war.h>
+
+inline void __delay(unsigned int loops)
+{
+ __asm__ __volatile__ (
+ " .set noreorder \n"
+ " .align 3 \n"
+ "1: bnez %0, 1b \n"
+ " subu %0, 1 \n"
+ " .set reorder \n"
+ : "=r" (loops)
+ : "0" (loops));
+}
+EXPORT_SYMBOL(__delay);
+
+/*
+ * Division by multiplication: you don't have to worry about
+ * loss of precision.
+ *
+ * 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)
+ */
+
+void __udelay(unsigned long us)
+{
+ unsigned int lpj = current_cpu_data.udelay_val;
+
+ __delay((us * 0x000010c7 * HZ * lpj) >> 32);
+}
+EXPORT_SYMBOL(__udelay);
+
+void __ndelay(unsigned long ns)
+{
+ unsigned int lpj = current_cpu_data.udelay_val;
+
+ __delay((us * 0x00000005 * HZ * lpj) >> 32);
+}
+EXPORT_SYMBOL(__ndelay);