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Roll CRC16-CCITT into the hash infrastructure

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The CRC16-CCITT checksum function is useful for space-constrained
applications (such as obtaining a checksum across a 2KBit or 4KBit
EEPROM) in boot applications. It has not been accessible from boot
scripts until now (due to not having a dedicated command and not being
supported by the hash infrstructure) limiting its applicability
outside of custom commands.

This adds the CRC16-CCITT (poly 0x1021, init 0x0) algorithm to the
list of available hashes and adds a new crc16_ccitt_wd_buf() to make
this possible.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[trini: Fix building crc16.o for SPL/TPL]
Signed-off-by: Tom Rini <trini@konsulko.com>
This commit is contained in:
Philipp Tomsich
2018-11-25 19:22:19 +01:00
committed by Tom Rini
parent a740ee913e
commit 51c2345bd2
5 changed files with 66 additions and 6 deletions
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23
lib/crc16.c
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@@ -22,6 +22,11 @@
*==========================================================================
*/
#ifdef USE_HOSTCC
#include <arpa/inet.h>
#else
#include <common.h>
#endif
#include <u-boot/crc.h>
/* Table of CRC constants - implements x^16+x^12+x^5+1 */
@@ -60,14 +65,20 @@ static const uint16_t crc16_tab[] = {
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
};
uint16_t crc16_ccitt(uint16_t crc_start, unsigned char *buf, int len)
uint16_t crc16_ccitt(uint16_t cksum, const unsigned char *buf, int len)
{
int i;
uint16_t cksum;
cksum = crc_start;
for (i = 0; i < len; i++)
for (int i = 0; i < len; i++)
cksum = crc16_tab[((cksum>>8) ^ *buf++) & 0xff] ^ (cksum << 8);
return cksum;
}
void crc16_ccitt_wd_buf(const uint8_t *in, uint len,
uint8_t *out, uint chunk_sz)
{
uint16_t crc;
crc = crc16_ccitt(0, in, len);
crc = htons(crc);
memcpy(out, &crc, sizeof(crc));
}