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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
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@ -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 document: All of this has been reverse-engineered and may thus be erroneous
and/or incomplete. 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 All multi-byte values are little-endian, there is no implicit padding between
values. values.

2
drivers/mfd/Kconfig
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@ -2255,7 +2255,7 @@ config MFD_VEXPRESS_SYSREG
config RAVE_SP_CORE config RAVE_SP_CORE
tristate "RAVE SP MCU core driver" tristate "RAVE SP MCU core driver"
depends on SERIAL_DEV_BUS depends on SERIAL_DEV_BUS
select CRC_CCITT select CRC_ITU_T
help help
Select this to get support for the Supervisory Processor Select this to get support for the Supervisory Processor
device found on several devices in RAVE line of hardware. 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/atomic.h>
#include <linux/crc-ccitt.h> #include <linux/crc-itu-t.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/export.h> #include <linux/export.h>
#include <linux/init.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) 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, * While the rest of the wire protocol is little-endian,

2
drivers/platform/surface/aggregator/Kconfig
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@ -5,7 +5,7 @@ menuconfig SURFACE_AGGREGATOR
tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers" tristate "Microsoft Surface System Aggregator Module Subsystem and Drivers"
depends on SERIAL_DEV_BUS depends on SERIAL_DEV_BUS
depends on ACPI && !RISCV depends on ACPI && !RISCV
select CRC_CCITT select CRC_ITU_T
help help
The Surface System Aggregator Module (Surface SAM or SSAM) is an The Surface System Aggregator Module (Surface SAM or SSAM) is an
embedded controller (EC) found on 5th- and later-generation Microsoft embedded controller (EC) found on 5th- and later-generation Microsoft

7
include/linux/crc-ccitt.h
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@ -5,19 +5,12 @@
#include <linux/types.h> #include <linux/types.h>
extern u16 const crc_ccitt_table[256]; 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(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) static inline u16 crc_ccitt_byte(u16 crc, const u8 c)
{ {
return (crc >> 8) ^ crc_ccitt_table[(crc ^ c) & 0xff]; 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 */ #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 #ifndef _LINUX_SURFACE_AGGREGATOR_SERIAL_HUB_H
#define _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/kref.h>
#include <linux/ktime.h> #include <linux/ktime.h>
#include <linux/list.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) 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); 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 * crc_ccitt - recompute the CRC (CRC-CCITT variant) for the data
* buffer * buffer
@ -104,20 +64,5 @@ u16 crc_ccitt(u16 crc, u8 const *buffer, size_t len)
} }
EXPORT_SYMBOL(crc_ccitt); 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_DESCRIPTION("CRC-CCITT calculations");
MODULE_LICENSE("GPL"); MODULE_LICENSE("GPL");