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Groups > linux.kernel > #1650690

[PATCH v11 5/6] lib: add bitrev8x4()

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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>
---
 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

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[PATCH v11 0/6] FPGA Manager support for altera passive serial Joshua Clayton <stillcompiling@gmail.com> - 2017-05-25 19:40 +0200
  [PATCH v11 5/6] lib: add bitrev8x4() Joshua Clayton <stillcompiling@gmail.com> - 2017-05-25 19:40 +0200
  [PATCH v11 3/6] fpga manager: Add altera-ps-spi driver for Altera FPGAs Joshua Clayton <stillcompiling@gmail.com> - 2017-05-25 19:40 +0200
  [PATCH v11 4/6] ARM: dts: imx6q-evi: support altera-ps-spi Joshua Clayton <stillcompiling@gmail.com> - 2017-05-25 19:40 +0200
    Re: [PATCH v11 4/6] ARM: dts: imx6q-evi: support altera-ps-spi Andreas Färber <afaerber@suse.de> - 2017-06-02 18:40 +0200
      Re: [PATCH v11 4/6] ARM: dts: imx6q-evi: support altera-ps-spi stillcompiling@gmail.com - 2017-06-02 21:40 +0200
        Re: [PATCH v11 4/6] ARM: dts: imx6q-evi: support altera-ps-spi Andreas Färber <afaerber@suse.de> - 2017-06-02 22:00 +0200
          Re: [PATCH v11 4/6] ARM: dts: imx6q-evi: support altera-ps-spi stillcompiling@gmail.com - 2017-06-02 23:20 +0200
            Re: [PATCH v11 4/6] ARM: dts: imx6q-evi: support altera-ps-spi Alan Tull <atull@kernel.org> - 2017-06-05 17:20 +0200
  [PATCH v11 1/6] fpga: Add flag to indicate SPI bitstream is bit-reversed Joshua Clayton <stillcompiling@gmail.com> - 2017-05-25 19:40 +0200
  Re: [PATCH v11 0/6] FPGA Manager support for altera passive serial Anatolij Gustschin <agust@denx.de> - 2017-06-02 18:00 +0200
  [PATCH v12 1/6] fpga: Add flag to indicate SPI bitstream is bit-reversed Joshua Clayton <stillcompiling@gmail.com> - 2017-06-02 22:40 +0200
    [PATCH v12 5/6] lib: add bitrev8x4() Joshua Clayton <stillcompiling@gmail.com> - 2017-06-02 22:40 +0200
      Re: [PATCH v12 5/6] lib: add bitrev8x4() Alan Tull <atull@kernel.org> - 2017-06-05 17:20 +0200
    [PATCH v12 3/6] fpga manager: Add altera-ps-spi driver for Altera FPGAs Joshua Clayton <stillcompiling@gmail.com> - 2017-06-02 22:40 +0200
      Re: [PATCH v12 3/6] fpga manager: Add altera-ps-spi driver for Altera FPGAs Alan Tull <atull@kernel.org> - 2017-06-05 17:20 +0200
    [PATCH v12 2/6] doc: dt: document altera-passive-serial binding Joshua Clayton <stillcompiling@gmail.com> - 2017-06-02 22:40 +0200
      Re: [PATCH v12 2/6] doc: dt: document altera-passive-serial binding Alan Tull <atull@kernel.org> - 2017-06-05 17:20 +0200
    [PATCH v12 4/6] ARM: dts: imx6q-evi: support altera-ps-spi Joshua Clayton <stillcompiling@gmail.com> - 2017-06-02 22:40 +0200
      Re: [PATCH v12 4/6] ARM: dts: imx6q-evi: support altera-ps-spi Alan Tull <atull@kernel.org> - 2017-06-05 17:20 +0200
    Re: [PATCH v12 1/6] fpga: Add flag to indicate SPI bitstream is bit-reversed Alan Tull <atull@kernel.org> - 2017-06-05 17:20 +0200

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