diff options
Diffstat (limited to 'patches/features/all/lib-crcitut-bit-reversed.patch')
| -rw-r--r-- | patches/features/all/lib-crcitut-bit-reversed.patch | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/patches/features/all/lib-crcitut-bit-reversed.patch b/patches/features/all/lib-crcitut-bit-reversed.patch new file mode 100644 index 0000000..358c0d8 --- /dev/null +++ b/patches/features/all/lib-crcitut-bit-reversed.patch @@ -0,0 +1,79 @@ +From c450dd0d27ff5cd7b83084e381e0cc808db2554e Mon Sep 17 00:00:00 2001 +From: Darren Salt <linux@youmustbejoking.demon.co.uk> +Date: Sat, 11 Apr 2009 15:40:04 +0100 +Subject: [PATCH] crc-itu-t: add bit-reversed calculation + +Signed-off-by: Darren Salt <linux@youmustbejoking.demon.co.uk> +--- + include/linux/crc-itu-t.h | 10 ++++++++++ + lib/crc-itu-t.c | 18 ++++++++++++++++++ + 2 files changed, 28 insertions(+), 0 deletions(-) + +diff --git a/include/linux/crc-itu-t.h b/include/linux/crc-itu-t.h +index 84920f3..7b2b7ba 100644 +--- a/include/linux/crc-itu-t.h ++++ b/include/linux/crc-itu-t.h +@@ -6,6 +6,9 @@ + * Poly 0x0x1021 (x^16 + x^12 + x^15 + 1) + * Init 0 + * ++ * The bit-reversed buffer variants may be non-standard, but some firmware ++ * loaders require them. ++ * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ +@@ -14,15 +17,22 @@ + #define CRC_ITU_T_H + + #include <linux/types.h> ++#include <linux/bitrev.h> + + extern u16 const crc_itu_t_table[256]; + + extern u16 crc_itu_t(u16 crc, const u8 *buffer, size_t len); ++extern u16 crc_itu_t_bitreversed(u16 crc, const u8 *buffer, size_t len); + + static inline u16 crc_itu_t_byte(u16 crc, const u8 data) + { + return (crc << 8) ^ crc_itu_t_table[((crc >> 8) ^ data) & 0xff]; + } + ++static inline u16 crc_itu_t_bitreversed_byte(u16 crc, const u8 data) ++{ ++ return (crc << 8) ^ crc_itu_t_table[((crc >> 8) ^ bitrev8(data)) & 0xff]; ++} ++ + #endif /* CRC_ITU_T_H */ + +diff --git a/lib/crc-itu-t.c b/lib/crc-itu-t.c +index a63472b..886981e 100644 +--- a/lib/crc-itu-t.c ++++ b/lib/crc-itu-t.c +@@ -64,6 +64,23 @@ u16 crc_itu_t(u16 crc, const u8 *buffer, size_t len) + } + EXPORT_SYMBOL(crc_itu_t); + ++/** ++ * crc_itu_t_bitreversed - Compute the CRC-ITU-T for a bit-reversed data buffer ++ * ++ * @crc: previous CRC value ++ * @buffer: data pointer ++ * @len: number of bytes in the buffer ++ * ++ * Returns the updated CRC value ++ */ ++u16 crc_itu_t_bitreversed(u16 crc, const u8 *buffer, size_t len) ++{ ++ while (len--) ++ crc = crc_itu_t_bitreversed_byte(crc, *buffer++); ++ return crc; ++} ++EXPORT_SYMBOL(crc_itu_t_bitreversed); ++ + MODULE_DESCRIPTION("CRC ITU-T V.41 calculations"); + MODULE_LICENSE("GPL"); + +-- +1.5.6.5 + |