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From: Alan Tull <atull@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, linux-fpga@vger.kernel.org,
	Moritz Fischer <moritz.fischer@ettus.com>,
	delicious.quinoa@gmail.com,
	Joshua Clayton <stillcompiling@gmail.com>,
	Alan Tull <atull@kernel.org>
Subject: [PATCH 08/10] lib: add bitrev8x4()
Date: Mon,  5 Jun 2017 14:07:39 -0500	[thread overview]
Message-ID: <20170605190741.10508-9-atull@kernel.org> (raw)
In-Reply-To: <20170605190741.10508-1-atull@kernel.org>

From: Joshua Clayton <stillcompiling@gmail.com>

Add a function to reverse bytes within a 32 bit word.
Operate on a u32 rather than individual bytes.

Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
Signed-off-by: Alan Tull <atull@kernel.org>
---
 include/linux/bitrev.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index fb790b8449c1..b97be27e5a85 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -29,6 +29,8 @@ static inline u32 __bitrev32(u32 x)
 
 #endif /* CONFIG_HAVE_ARCH_BITREVERSE */
 
+#define __bitrev8x4(x)	(__bitrev32(swab32(x)))
+
 #define __constant_bitrev32(x)	\
 ({					\
 	u32 __x = x;			\
@@ -50,6 +52,15 @@ static inline u32 __bitrev32(u32 x)
 	__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;			\
@@ -75,6 +86,14 @@ static inline u32 __bitrev32(u32 x)
 	__bitrev16(__x);				\
  })
 
+#define bitrev8x4(x) \
+({			\
+	u32 __x = x;	\
+	__builtin_constant_p(__x) ?	\
+	__constant_bitrev8x4(__x) :			\
+	__bitrev8x4(__x);				\
+ })
+
 #define bitrev8(x) \
 ({			\
 	u8 __x = x;	\
-- 
2.11.0

  parent reply	other threads:[~2017-06-05 19:07 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-05 19:07 [PATCH 00/10] patches for fpga Alan Tull
2017-06-05 19:07 ` [PATCH 01/10] dt-bindings: fpga: Add bindings document for Xilinx LogiCore PR Decoupler Alan Tull
2017-06-05 19:07 ` [PATCH 02/10] Make FPGA a menuconfig to ease disabling it all Alan Tull
2017-06-05 19:07 ` [PATCH 03/10] fpga: allow to compile-test Altera FPGA bridge drivers Alan Tull
2017-06-06 13:45   ` kbuild test robot
2017-06-09  9:49   ` Greg Kroah-Hartman
2017-06-09 13:44     ` Tobias Klauser
2017-06-10  3:55       ` Alan Tull
2017-06-05 19:07 ` [PATCH 04/10] fpga: Add flag to indicate SPI bitstream is bit-reversed Alan Tull
2017-06-05 19:07 ` [PATCH 05/10] doc: dt: document altera-passive-serial binding Alan Tull
2017-06-05 19:07 ` [PATCH 06/10] fpga manager: Add altera-ps-spi driver for Altera FPGAs Alan Tull
2017-06-09  9:51   ` Greg Kroah-Hartman
2017-06-09 13:18     ` Anatolij Gustschin
2017-06-09 22:07       ` stillcompiling
2017-06-10 14:43     ` Alan Tull
2017-06-05 19:07 ` [PATCH 07/10] ARM: dts: imx6q-evi: support altera-ps-spi Alan Tull
2017-06-05 19:07 ` Alan Tull [this message]
2017-06-05 19:07 ` [PATCH 09/10] fpga-manager: altera-ps-spi: use bitrev8x4 Alan Tull
2017-06-05 19:07 ` [PATCH 10/10] of: Add vendor prefix for Lattice Semiconductor Alan Tull

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