From 90ca22513ed5d7cf546c7c8d35a03ec2a2f5c87e Mon Sep 17 00:00:00 2001 From: Mathis Marion Date: Tue, 19 Dec 2023 14:11:54 +0100 Subject: [PATCH] lib: crc_ccitt_false() is identical to crc_itu_t() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit crc_ccitt_false() was introduced in commit 0d85adb5fbd33 ("lib/crc-ccitt: Add CCITT-FALSE CRC16 variant"), but it is redundant with crc_itu_t(). Since the latter is more used, it is the one being kept. Link: https://lkml.kernel.org/r/20231219131154.748577-1-Mathis.Marion@silabs.com Signed-off-by: Mathis Marion Cc: Andrey Smirnov Cc: Andrey Vostrikov Cc: Jérôme Pouiller Signed-off-by: Andrew Morton --- .../driver-api/surface_aggregator/ssh.rst | 2 +- drivers/mfd/Kconfig | 2 +- drivers/mfd/rave-sp.c | 4 +- drivers/platform/surface/aggregator/Kconfig | 2 +- include/linux/crc-ccitt.h | 7 --- include/linux/surface_aggregator/serial_hub.h | 4 +- lib/crc-ccitt.c | 55 ------------------- 7 files changed, 7 insertions(+), 69 deletions(-) diff --git a/Documentation/driver-api/surface_aggregator/ssh.rst b/Documentation/driver-api/surface_aggregator/ssh.rst index b955b673838b..58a757319931 100644 --- a/Documentation/driver-api/surface_aggregator/ssh.rst +++ b/Documentation/driver-api/surface_aggregator/ssh.rst @@ -39,7 +39,7 @@ Note that the standard disclaimer for this subsystem also applies to this document: All of this has been reverse-engineered and may thus be erroneous and/or incomplete. -All CRCs used in the following are two-byte ``crc_ccitt_false(0xffff, ...)``. +All CRCs used in the following are two-byte ``crc_itu_t(0xffff, ...)``. All multi-byte values are little-endian, there is no implicit padding between values. diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index 90ce58fd629e..925c19ee513b 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -2255,7 +2255,7 @@ config MFD_VEXPRESS_SYSREG config RAVE_SP_CORE tristate "RAVE SP MCU core driver" depends on SERIAL_DEV_BUS - select CRC_CCITT + select CRC_ITU_T help Select this to get support for the Supervisory Processor device found on several devices in RAVE line of hardware. diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c index da50eba10014..f62422740de2 100644 --- a/drivers/mfd/rave-sp.c +++ b/drivers/mfd/rave-sp.c @@ -9,7 +9,7 @@ */ #include -#include +#include #include #include #include @@ -251,7 +251,7 @@ static void csum_8b2c(const u8 *buf, size_t size, u8 *crc) static void csum_ccitt(const u8 *buf, size_t size, u8 *crc) { - const u16 calculated = crc_ccitt_false(0xffff, buf, size); + const u16 calculated = crc_itu_t(0xffff, buf, size); /* * While the rest of the wire protocol is little-endian, diff --git a/drivers/platform/surface/aggregator/Kconfig b/drivers/platform/surface/aggregator/Kconfig index 88afc38ffdc5..957c216c180c 100644 --- a/drivers/platform/surface/aggregator/Kconfig +++ b/drivers/platform/surface/aggregator/Kconfig @@ -5,7 +5,7 @@ menuconfig SURFACE_AGGREGATOR tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers" depends on SERIAL_DEV_BUS depends on ACPI && !RISCV - select CRC_CCITT + select CRC_ITU_T help The Surface System Aggregator Module (Surface SAM or SSAM) is an embedded controller (EC) found on 5th- and later-generation Microsoft diff --git a/include/linux/crc-ccitt.h b/include/linux/crc-ccitt.h index 72c92c396bb8..cd4f420231ba 100644 --- a/include/linux/crc-ccitt.h +++ b/include/linux/crc-ccitt.h @@ -5,19 +5,12 @@ #include extern u16 const crc_ccitt_table[256]; -extern u16 const crc_ccitt_false_table[256]; extern u16 crc_ccitt(u16 crc, const u8 *buffer, size_t len); -extern u16 crc_ccitt_false(u16 crc, const u8 *buffer, size_t len); static inline u16 crc_ccitt_byte(u16 crc, const u8 c) { return (crc >> 8) ^ crc_ccitt_table[(crc ^ c) & 0xff]; } -static inline u16 crc_ccitt_false_byte(u16 crc, const u8 c) -{ - return (crc << 8) ^ crc_ccitt_false_table[(crc >> 8) ^ c]; -} - #endif /* _LINUX_CRC_CCITT_H */ diff --git a/include/linux/surface_aggregator/serial_hub.h b/include/linux/surface_aggregator/serial_hub.h index 5c4ae1a26183..d8dbef6b7fc2 100644 --- a/include/linux/surface_aggregator/serial_hub.h +++ b/include/linux/surface_aggregator/serial_hub.h @@ -12,7 +12,7 @@ #ifndef _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H #define _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H -#include +#include #include #include #include @@ -188,7 +188,7 @@ static_assert(sizeof(struct ssh_command) == 8); */ static inline u16 ssh_crc(const u8 *buf, size_t len) { - return crc_ccitt_false(0xffff, buf, len); + return crc_itu_t(0xffff, buf, len); } /* diff --git a/lib/crc-ccitt.c b/lib/crc-ccitt.c index d1a7d29d2ac9..9cddf35d3b66 100644 --- a/lib/crc-ccitt.c +++ b/lib/crc-ccitt.c @@ -49,46 +49,6 @@ u16 const crc_ccitt_table[256] = { }; EXPORT_SYMBOL(crc_ccitt_table); -/* - * Similar table to calculate CRC16 variant known as CRC-CCITT-FALSE - * Reflected bits order, does not augment final value. - */ -u16 const crc_ccitt_false_table[256] = { - 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, - 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, - 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, - 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, - 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, - 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, - 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, - 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, - 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, - 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, - 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, - 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, - 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, - 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, - 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, - 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, - 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, - 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, - 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, - 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, - 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, - 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, - 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, - 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, - 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, - 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, - 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, - 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, - 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, - 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, - 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, - 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 -}; -EXPORT_SYMBOL(crc_ccitt_false_table); - /** * crc_ccitt - recompute the CRC (CRC-CCITT variant) for the data * buffer @@ -104,20 +64,5 @@ u16 crc_ccitt(u16 crc, u8 const *buffer, size_t len) } EXPORT_SYMBOL(crc_ccitt); -/** - * crc_ccitt_false - recompute the CRC (CRC-CCITT-FALSE variant) - * for the data buffer - * @crc: previous CRC value - * @buffer: data pointer - * @len: number of bytes in the buffer - */ -u16 crc_ccitt_false(u16 crc, u8 const *buffer, size_t len) -{ - while (len--) - crc = crc_ccitt_false_byte(crc, *buffer++); - return crc; -} -EXPORT_SYMBOL(crc_ccitt_false); - MODULE_DESCRIPTION("CRC-CCITT calculations"); MODULE_LICENSE("GPL");