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lib: crc_ccitt_false() is identical to crc_itu_t()

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crc_ccitt_false() was introduced in commit 0d85adb5fb ("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 <mathis.marion@silabs.com>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>
Cc: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Mathis Marion 2023-12-19 14:11:54 +01:00 committed by Andrew Morton
parent bc09d1dea8
commit 90ca22513e
7 changed files with 7 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/driver-api/surface_aggregator/ssh.rst
View File

@ -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.

2
drivers/mfd/Kconfig
View File

@ -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.

4
drivers/mfd/rave-sp.c
View File

@ -9,7 +9,7 @@
*/
#include <linux/atomic.h>
#include <linux/crc-ccitt.h>
#include <linux/crc-itu-t.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/init.h>
@ -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,

2
drivers/platform/surface/aggregator/Kconfig
View File

@ -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

7
include/linux/crc-ccitt.h
View File

@ -5,19 +5,12 @@
#include <linux/types.h>
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 */

4
include/linux/surface_aggregator/serial_hub.h
View File

@ -12,7 +12,7 @@
#ifndef _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H
#define _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H
#include <linux/crc-ccitt.h>
#include <linux/crc-itu-t.h>
#include <linux/kref.h>
#include <linux/ktime.h>
#include <linux/list.h>
@ -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);
}
/*

55
lib/crc-ccitt.c
View File

@ -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");