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authorDavid Howells <dhowells@redhat.com>2008-09-26 16:22:58 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-26 08:49:04 -0700
commitbc173c5789e1fc6065fd378edc815914b40ee86b (patch)
treed32e5ae62ca966e2f4672df65c81aec2e2241f0d
parentbde40fe071e327857b478a440c599f54d4fc14dd (diff)
downloadlinux-linaro-bc173c5789e1fc6065fd378edc815914b40ee86b.tar.gz
ARM: Delete ARM's own cnt32_to_63.h
Delete ARM's own cnt32_to_63.h as the copy in include/linux/ should now be used instead. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/arm/include/asm/cnt32_to_63.h78
1 files changed, 0 insertions, 78 deletions
diff --git a/arch/arm/include/asm/cnt32_to_63.h b/arch/arm/include/asm/cnt32_to_63.h
deleted file mode 100644
index 480c873fa74..00000000000
--- a/arch/arm/include/asm/cnt32_to_63.h
+++ /dev/null
@@ -1,78 +0,0 @@
-/*
- * include/asm/cnt32_to_63.h -- extend a 32-bit counter to 63 bits
- *
- * Author: Nicolas Pitre
- * Created: December 3, 2006
- * Copyright: MontaVista Software, Inc.
- *
- * 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.
- */
-
-#ifndef __INCLUDE_CNT32_TO_63_H__
-#define __INCLUDE_CNT32_TO_63_H__
-
-#include <linux/compiler.h>
-#include <asm/types.h>
-#include <asm/byteorder.h>
-
-/*
- * Prototype: u64 cnt32_to_63(u32 cnt)
- * Many hardware clock counters are only 32 bits wide and therefore have
- * a relatively short period making wrap-arounds rather frequent. This
- * is a problem when implementing sched_clock() for example, where a 64-bit
- * non-wrapping monotonic value is expected to be returned.
- *
- * To overcome that limitation, let's extend a 32-bit counter to 63 bits
- * in a completely lock free fashion. Bits 0 to 31 of the clock are provided
- * by the hardware while bits 32 to 62 are stored in memory. The top bit in
- * memory is used to synchronize with the hardware clock half-period. When
- * the top bit of both counters (hardware and in memory) differ then the
- * memory is updated with a new value, incrementing it when the hardware
- * counter wraps around.
- *
- * Because a word store in memory is atomic then the incremented value will
- * always be in synch with the top bit indicating to any potential concurrent
- * reader if the value in memory is up to date or not with regards to the
- * needed increment. And any race in updating the value in memory is harmless
- * as the same value would simply be stored more than once.
- *
- * The only restriction for the algorithm to work properly is that this
- * code must be executed at least once per each half period of the 32-bit
- * counter to properly update the state bit in memory. This is usually not a
- * problem in practice, but if it is then a kernel timer could be scheduled
- * to manage for this code to be executed often enough.
- *
- * Note that the top bit (bit 63) in the returned value should be considered
- * as garbage. It is not cleared here because callers are likely to use a
- * multiplier on the returned value which can get rid of the top bit
- * implicitly by making the multiplier even, therefore saving on a runtime
- * clear-bit instruction. Otherwise caller must remember to clear the top
- * bit explicitly.
- */
-
-/* this is used only to give gcc a clue about good code generation */
-typedef union {
- struct {
-#if defined(__LITTLE_ENDIAN)
- u32 lo, hi;
-#elif defined(__BIG_ENDIAN)
- u32 hi, lo;
-#endif
- };
- u64 val;
-} cnt32_to_63_t;
-
-#define cnt32_to_63(cnt_lo) \
-({ \
- static volatile u32 __m_cnt_hi = 0; \
- cnt32_to_63_t __x; \
- __x.hi = __m_cnt_hi; \
- __x.lo = (cnt_lo); \
- if (unlikely((s32)(__x.hi ^ __x.lo) < 0)) \
- __m_cnt_hi = __x.hi = (__x.hi ^ 0x80000000) + (__x.hi >> 31); \
- __x.val; \
-})
-
-#endif