On 17 October 2015 at 02:11, Fabio Estevam festevam@gmail.com wrote:
From: Fabio Estevam fabio.estevam@freescale.com
Use the log2 and fls64 header files directly from the kernel.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com
Changes since v7:
- None
include/asm-generic/bitops/fls64.h | 36 +++++++ include/linux/bitops.h | 9 ++ include/linux/log2.h | 208 +++++++++++++++++++++++++++++++++++++ 3 files changed, 253 insertions(+) create mode 100644 include/asm-generic/bitops/fls64.h create mode 100644 include/linux/log2.h
diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h new file mode 100644 index 0000000..86d403f --- /dev/null +++ b/include/asm-generic/bitops/fls64.h @@ -0,0 +1,36 @@ +#ifndef _ASM_GENERIC_BITOPS_FLS64_H_ +#define _ASM_GENERIC_BITOPS_FLS64_H_
+#include <asm/types.h>
+/**
- fls64 - find last set bit in a 64-bit word
- @x: the word to search
- This is defined in a similar way as the libc and compiler builtin
- ffsll, but returns the position of the most significant set bit.
- fls64(value) returns 0 if value is 0 or the position of the last
- set bit if value is nonzero. The last (most significant) bit is
- at position 64.
- */
+#if BITS_PER_LONG == 32 +static inline int fls64(__u64 x) +{
__u32 h = x >> 32;if (h)return fls(h) + 32;return fls(x);+} +#elif BITS_PER_LONG == 64 +static inline int fls64(__u64 x) +{
if (x == 0)return 0;return __fls(x) + 1;+} +#else +#error BITS_PER_LONG not 32 or 64 +#endif
+#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */ diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 7d30ace..647733f 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -129,6 +129,15 @@ static inline unsigned int generic_hweight8(unsigned int w) # define fls generic_fls #endif
+#include <asm-generic/bitops/fls64.h>
Please check this include, we can't assume to use generic one in common header file there is one more fls64 from powerpc?
+static inline unsigned fls_long(unsigned long l) +{
if (sizeof(l) == 4)return fls(l);return fls64(l);+}
/**
- __set_bit - Set a bit in memory
- @nr: the bit to set
diff --git a/include/linux/log2.h b/include/linux/log2.h new file mode 100644 index 0000000..fd7ff3d --- /dev/null +++ b/include/linux/log2.h @@ -0,0 +1,208 @@ +/* Integer base 2 logarithm calculation
- Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
- Written by David Howells (dhowells@redhat.com)
- This program is free software; you can redistribute it and/or
- modify it under the terms of the GNU General Public License
- as published by the Free Software Foundation; either version
- 2 of the License, or (at your option) any later version.
- */
Wolfgang Denk/Tom,
This file is copied from Linux, will this license notes will also be same or any changes?
+#ifndef _LINUX_LOG2_H +#define _LINUX_LOG2_H
+#include <linux/types.h> +#include <linux/bitops.h>
+/*
- deal with unrepresentable constant logarithms
- */
+extern __attribute__((const, noreturn)) +int ____ilog2_NaN(void);
+/*
- non-constant log of base 2 calculators
- the arch may override these in asm/bitops.h if they can be implemented
- more efficiently than using fls() and fls64()
- the arch is not required to handle n==0 if implementing the fallback
- */
+#ifndef CONFIG_ARCH_HAS_ILOG2_U32 +static inline __attribute__((const)) +int __ilog2_u32(u32 n) +{
return fls(n) - 1;+} +#endif
+#ifndef CONFIG_ARCH_HAS_ILOG2_U64 +static inline __attribute__((const)) +int __ilog2_u64(u64 n) +{
return fls64(n) - 1;+} +#endif
+/*
- Determine whether some value is a power of two, where zero is
- *not* considered a power of two.
- */
+static inline __attribute__((const)) +bool is_power_of_2(unsigned long n) +{
return (n != 0 && ((n & (n - 1)) == 0));+}
+/*
- round up to nearest power of two
- */
+static inline __attribute__((const)) +unsigned long __roundup_pow_of_two(unsigned long n) +{
return 1UL << fls_long(n - 1);+}
+/*
- round down to nearest power of two
- */
+static inline __attribute__((const)) +unsigned long __rounddown_pow_of_two(unsigned long n) +{
return 1UL << (fls_long(n) - 1);+}
+/**
- ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value
- @n - parameter
- constant-capable log of base 2 calculation
- this can be used to initialise global variables from constant data, hence
- the massive ternary operator construction
- selects the appropriately-sized optimised version depending on sizeof(n)
- */
+#define ilog2(n) \ +( \
__builtin_constant_p(n) ? ( \(n) < 1 ? ____ilog2_NaN() : \(n) & (1ULL << 63) ? 63 : \(n) & (1ULL << 62) ? 62 : \(n) & (1ULL << 61) ? 61 : \(n) & (1ULL << 60) ? 60 : \(n) & (1ULL << 59) ? 59 : \(n) & (1ULL << 58) ? 58 : \(n) & (1ULL << 57) ? 57 : \(n) & (1ULL << 56) ? 56 : \(n) & (1ULL << 55) ? 55 : \(n) & (1ULL << 54) ? 54 : \(n) & (1ULL << 53) ? 53 : \(n) & (1ULL << 52) ? 52 : \(n) & (1ULL << 51) ? 51 : \(n) & (1ULL << 50) ? 50 : \(n) & (1ULL << 49) ? 49 : \(n) & (1ULL << 48) ? 48 : \(n) & (1ULL << 47) ? 47 : \(n) & (1ULL << 46) ? 46 : \(n) & (1ULL << 45) ? 45 : \(n) & (1ULL << 44) ? 44 : \(n) & (1ULL << 43) ? 43 : \(n) & (1ULL << 42) ? 42 : \(n) & (1ULL << 41) ? 41 : \(n) & (1ULL << 40) ? 40 : \(n) & (1ULL << 39) ? 39 : \(n) & (1ULL << 38) ? 38 : \(n) & (1ULL << 37) ? 37 : \(n) & (1ULL << 36) ? 36 : \(n) & (1ULL << 35) ? 35 : \(n) & (1ULL << 34) ? 34 : \(n) & (1ULL << 33) ? 33 : \(n) & (1ULL << 32) ? 32 : \(n) & (1ULL << 31) ? 31 : \(n) & (1ULL << 30) ? 30 : \(n) & (1ULL << 29) ? 29 : \(n) & (1ULL << 28) ? 28 : \(n) & (1ULL << 27) ? 27 : \(n) & (1ULL << 26) ? 26 : \(n) & (1ULL << 25) ? 25 : \(n) & (1ULL << 24) ? 24 : \(n) & (1ULL << 23) ? 23 : \(n) & (1ULL << 22) ? 22 : \(n) & (1ULL << 21) ? 21 : \(n) & (1ULL << 20) ? 20 : \(n) & (1ULL << 19) ? 19 : \(n) & (1ULL << 18) ? 18 : \(n) & (1ULL << 17) ? 17 : \(n) & (1ULL << 16) ? 16 : \(n) & (1ULL << 15) ? 15 : \(n) & (1ULL << 14) ? 14 : \(n) & (1ULL << 13) ? 13 : \(n) & (1ULL << 12) ? 12 : \(n) & (1ULL << 11) ? 11 : \(n) & (1ULL << 10) ? 10 : \(n) & (1ULL << 9) ? 9 : \(n) & (1ULL << 8) ? 8 : \(n) & (1ULL << 7) ? 7 : \(n) & (1ULL << 6) ? 6 : \(n) & (1ULL << 5) ? 5 : \(n) & (1ULL << 4) ? 4 : \(n) & (1ULL << 3) ? 3 : \(n) & (1ULL << 2) ? 2 : \(n) & (1ULL << 1) ? 1 : \(n) & (1ULL << 0) ? 0 : \____ilog2_NaN() \) : \(sizeof(n) <= 4) ? \__ilog2_u32(n) : \__ilog2_u64(n) \- )
+/**
- roundup_pow_of_two - round the given value up to nearest power of two
- @n - parameter
- round the given value up to the nearest power of two
- the result is undefined when n == 0
- this can be used to initialise global variables from constant data
- */
+#define roundup_pow_of_two(n) \ +( \
__builtin_constant_p(n) ? ( \(n == 1) ? 1 : \(1UL << (ilog2((n) - 1) + 1)) \) : \__roundup_pow_of_two(n) \- )
+/**
- rounddown_pow_of_two - round the given value down to nearest power of two
- @n - parameter
- round the given value down to the nearest power of two
- the result is undefined when n == 0
- this can be used to initialise global variables from constant data
- */
+#define rounddown_pow_of_two(n) \ +( \
__builtin_constant_p(n) ? ( \(1UL << ilog2(n))) : \__rounddown_pow_of_two(n) \- )
+/**
- order_base_2 - calculate the (rounded up) base 2 order of the argument
- @n: parameter
- The first few values calculated by this routine:
- ob2(0) = 0
- ob2(1) = 0
- ob2(2) = 1
- ob2(3) = 2
- ob2(4) = 2
- ob2(5) = 3
- ... and so on.
- */
+#define order_base_2(n) ilog2(roundup_pow_of_two(n))
+#endif /* _LINUX_LOG2_H */
1.9.1
-- Jagan.