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* [U-Boot] [PATCH v7 01/21] include: Add log2 header from the kernel
@ 2015-11-05 14:43 Fabio Estevam
  2015-11-05 14:43 ` [U-Boot] [PATCH v7 02/21] include: Add generic bitops headers Fabio Estevam
                   ` (21 more replies)
  0 siblings, 22 replies; 66+ messages in thread
From: Fabio Estevam @ 2015-11-05 14:43 UTC (permalink / raw)
  To: u-boot

Use the log2 header files from the kernel.

Imported from kernel 4.2.3.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>
---
Changes since v6:
- None

 include/linux/log2.h | 205 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 205 insertions(+)
 create mode 100644 include/linux/log2.h

diff --git a/include/linux/log2.h b/include/linux/log2.h
new file mode 100644
index 0000000..aa1de63
--- /dev/null
+++ b/include/linux/log2.h
@@ -0,0 +1,205 @@
+/* Integer base 2 logarithm calculation
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells at redhat.com)
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#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

^ permalink raw reply related	[flat|nested] 66+ messages in thread

end of thread, other threads:[~2015-12-01 20:01 UTC | newest]

Thread overview: 66+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-11-05 14:43 [U-Boot] [PATCH v7 01/21] include: Add log2 header from the kernel Fabio Estevam
2015-11-05 14:43 ` [U-Boot] [PATCH v7 02/21] include: Add generic bitops headers Fabio Estevam
2015-11-06 12:22   ` Tom Rini
2015-12-01 17:26   ` York Sun
2015-12-01 20:01     ` Simon Glass
2015-11-05 14:43 ` [U-Boot] [PATCH v7 03/21] ARM: Use the " Fabio Estevam
2015-11-06 12:22   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 04/21] x86: " Fabio Estevam
2015-11-06 12:22   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 05/21] m68k: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 06/21] blackfin: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 07/21] sh: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 08/21] microblaze: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 09/21] sandbox: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 10/21] sparc: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 11/21] openrisc: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 12/21] nds32: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 13/21] nios2: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 14/21] mips: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 15/21] arc: " Fabio Estevam
2015-11-06 12:23   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 16/21] avr32: " Fabio Estevam
2015-11-06 12:24   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 17/21] bitops: Add fls_long and __ffs64 Fabio Estevam
2015-11-06 12:24   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 18/21] compat: Remove is_power_of_2() definition Fabio Estevam
2015-11-06 12:24   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 19/21] powerpc: Remove __ilog2_u64 and ffs4 from bitops Fabio Estevam
2015-11-06 12:24   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 20/21] sf: Add SPI protection mechanism from the kernel Fabio Estevam
2015-11-06 12:24   ` Tom Rini
2015-11-05 14:43 ` [U-Boot] [PATCH v7 21/21] sf: Add SPI NOR protection mechanism Fabio Estevam
2015-11-06 12:24   ` Tom Rini
2015-11-11  0:09     ` Simon Glass
2015-11-11  0:29       ` Tom Rini
2015-11-11  0:51       ` Fabio Estevam
2015-11-11  2:56         ` Simon Glass
2015-11-11  9:43           ` Fabio Estevam
2015-11-11 16:25             ` Jagan Teki
2015-11-13  9:20               ` Bin Meng
2015-11-11 14:04           ` Fabio Estevam
2015-11-13 10:41             ` Bin Meng
2015-11-16  1:34               ` Simon Glass
2015-11-16  1:58                 ` Tom Rini
2015-11-16 21:07                   ` Simon Glass
2015-11-17  6:43                     ` Jagan Teki
2015-11-16 20:57                 ` Fabio Estevam
2015-11-05 15:51 ` [U-Boot] [PATCH v7 01/21] include: Add log2 header from the kernel Tom Rini
2015-11-05 15:51   ` Fabio Estevam
2015-11-05 16:35     ` Tom Rini
2015-11-05 17:53       ` Fabio Estevam
2015-11-05 19:10         ` Tom Rini
2015-11-05 20:07           ` Fabio Estevam
2015-11-06  1:40             ` Tom Rini
2015-11-06 11:08               ` Fabio Estevam
2015-11-06 12:22 ` Tom Rini

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