From 9c2cb97e22a7a12bf87d0af7e90156afe7a78d21 Mon Sep 17 00:00:00 2001
From: Bin Meng <bmeng.cn@gmail.com>
Date: Thu, 2 Aug 2018 23:58:02 -0700
Subject: [PATCH] lib: bitrev: Sync with Linux kernel v4.17

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 include/linux/bitrev.h | 102 +++++++++++++++++++++++++++++++++++++----
 lib/bitrev.c           |  28 ++++-------
 2 files changed, 102 insertions(+), 28 deletions(-)

diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index cc5abd7396..8ec9411aad 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -1,21 +1,105 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * Based on bitrev from the Linux kernel, by Akinobu Mita
- */
-
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_BITREV_H
 #define _LINUX_BITREV_H
 
 #include <linux/types.h>
 
-extern u8 const byte_rev_table[256];
+#ifdef CONFIG_HAVE_ARCH_BITREVERSE
+#include <asm/bitrev.h>
+
+#define __bitrev32 __arch_bitrev32
+#define __bitrev16 __arch_bitrev16
+#define __bitrev8 __arch_bitrev8
 
-static inline u8 bitrev8(u8 byte)
+#else
+extern u8 const byte_rev_table[256];
+static inline u8 __bitrev8(u8 byte)
 {
 	return byte_rev_table[byte];
 }
 
-u16 bitrev16(u16 in);
-u32 bitrev32(u32 in);
+static inline u16 __bitrev16(u16 x)
+{
+	return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8);
+}
+
+static inline u32 __bitrev32(u32 x)
+{
+	return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16);
+}
+
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
+
+#define __bitrev8x4(x)	(__bitrev32(swab32(x)))
+
+#define __constant_bitrev32(x)		\
+({					\
+	u32 __x = x;			\
+	__x = (__x >> 16) | (__x << 16);\
+	__x = ((__x & (u32)0xFF00FF00UL) >> 8) | ((__x & (u32)0x00FF00FFUL) << 8);	\
+	__x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4);	\
+	__x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2);	\
+	__x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1);	\
+	__x;				\
+})
+
+#define __constant_bitrev16(x)		\
+({					\
+	u16 __x = x;			\
+	__x = (__x >> 8) | (__x << 8);	\
+	__x = ((__x & (u16)0xF0F0U) >> 4) | ((__x & (u16)0x0F0FU) << 4); \
+	__x = ((__x & (u16)0xCCCCU) >> 2) | ((__x & (u16)0x3333U) << 2); \
+	__x = ((__x & (u16)0xAAAAU) >> 1) | ((__x & (u16)0x5555U) << 1); \
+	__x;				\
+})
+
+#define __constant_bitrev8x4(x)		\
+({					\
+	u32 __x = x;			\
+	__x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4);	\
+	__x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2);	\
+	__x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1);	\
+	__x;				\
+})
+
+#define __constant_bitrev8(x)		\
+({					\
+	u8 __x = x;			\
+	__x = (__x >> 4) | (__x << 4);	\
+	__x = ((__x & (u8)0xCCU) >> 2) | ((__x & (u8)0x33U) << 2);	\
+	__x = ((__x & (u8)0xAAU) >> 1) | ((__x & (u8)0x55U) << 1);	\
+	__x;				\
+})
+
+#define bitrev32(x)			\
+({					\
+	u32 __x = x;			\
+	__builtin_constant_p(__x) ?	\
+	__constant_bitrev32(__x) :	\
+	__bitrev32(__x);		\
+})
+
+#define bitrev16(x)			\
+({					\
+	u16 __x = x;			\
+	__builtin_constant_p(__x) ?	\
+	__constant_bitrev16(__x) :	\
+	__bitrev16(__x);		\
+})
+
+#define bitrev8x4(x)			\
+({					\
+	u32 __x = x;			\
+	__builtin_constant_p(__x) ?	\
+	__constant_bitrev8x4(__x) :	\
+	__bitrev8x4(__x);		\
+})
 
+#define bitrev8(x)			\
+({					\
+	u8 __x = x;			\
+	__builtin_constant_p(__x) ?	\
+	__constant_bitrev8(__x) :	\
+	__bitrev8(__x)	;		\
+})
 #endif /* _LINUX_BITREV_H */
diff --git a/lib/bitrev.c b/lib/bitrev.c
index 4d494e1733..08231c056c 100644
--- a/lib/bitrev.c
+++ b/lib/bitrev.c
@@ -1,13 +1,14 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- *
- * Based on bitrev from the Linux kernel, by Akinobu Mita
- */
-
+// SPDX-License-Identifier: GPL-2.0
 
+#ifndef CONFIG_HAVE_ARCH_BITREVERSE
 #include <linux/types.h>
+#include <linux/compat.h>
 #include <linux/bitrev.h>
 
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
+MODULE_DESCRIPTION("Bit ordering reversal functions");
+MODULE_LICENSE("GPL");
+
 const u8 byte_rev_table[256] = {
 	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
 	0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
@@ -42,17 +43,6 @@ const u8 byte_rev_table[256] = {
 	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
 	0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
 };
+EXPORT_SYMBOL_GPL(byte_rev_table);
 
-u16 bitrev16(u16 x)
-{
-	return (bitrev8(x & 0xff) << 8) | bitrev8(x >> 8);
-}
-
-/**
- * bitrev32 - reverse the order of bits in a u32 value
- * @x: value to be bit-reversed
- */
-u32 bitrev32(u32 x)
-{
-	return (bitrev16(x & 0xffff) << 16) | bitrev16(x >> 16);
-}
+#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
-- 
2.30.2