Roll CRC16-CCITT into the hash infrastructure

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

View file

@ -85,6 +85,33 @@ static int hash_finish_sha256(struct hash_algo *algo, void *ctx, void
}
#endif
static int hash_init_crc16_ccitt(struct hash_algo *algo, void **ctxp)
{
uint16_t *ctx = malloc(sizeof(uint16_t));
*ctx = 0;
*ctxp = ctx;
return 0;
}
static int hash_update_crc16_ccitt(struct hash_algo *algo, void *ctx,
const void *buf, unsigned int size,
int is_last)
{
*((uint16_t *)ctx) = crc16_ccitt(*((uint16_t *)ctx), buf, size);
return 0;
}
static int hash_finish_crc16_ccitt(struct hash_algo *algo, void *ctx,
void *dest_buf, int size)
{
if (size < algo->digest_size)
return -1;
*((uint16_t *)dest_buf) = *((uint16_t *)ctx);
free(ctx);
return 0;
}
static int hash_init_crc32(struct hash_algo *algo, void **ctxp)
{
uint32_t *ctx = malloc(sizeof(uint32_t));
@ -159,6 +186,15 @@ static struct hash_algo hash_algo[] = {
#endif
},
#endif
{
.name = "crc16-ccitt",
.digest_size = 2,
.chunk_size = CHUNKSZ,
.hash_func_ws = crc16_ccitt_wd_buf,
.hash_init = hash_init_crc16_ccitt,
.hash_update = hash_update_crc16_ccitt,
.hash_finish = hash_finish_crc16_ccitt,
},
{
.name = "crc32",
.digest_size = 4,

View file

@ -13,6 +13,17 @@ unsigned int crc8(unsigned int crc_start, const unsigned char *vptr, int len);
/* lib/crc16.c - 16 bit CRC with polynomial x^16+x^12+x^5+1 (CRC-CCITT) */
uint16_t crc16_ccitt(uint16_t crc_start, const unsigned char *s, int len);
/**
* crc16_ccitt_wd_buf - Perform CRC16-CCIT on an input buffer and return the
* 16-bit result (network byte-order) in an output buffer
*
* @in: input buffer
* @len: input buffer length
* @out: output buffer (at least 2 bytes)
* @chunk_sz: ignored
*/
void crc16_ccitt_wd_buf(const uint8_t *in, uint len,
uint8_t *out, uint chunk_sz);
/* lib/crc32.c */
uint32_t crc32 (uint32_t, const unsigned char *, uint);

View file

@ -76,6 +76,7 @@ endif
ifdef CONFIG_SPL_BUILD
obj-$(CONFIG_SPL_YMODEM_SUPPORT) += crc16.o
obj-$(CONFIG_$(SPL_TPL_)HASH_SUPPORT) += crc16.o
obj-$(CONFIG_SPL_NET_SUPPORT) += net_utils.o
endif
obj-$(CONFIG_ADDR_MAP) += addr_map.o

View file

@ -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));
}

View file

@ -106,6 +106,7 @@ dumpimage-mkimage-objs := aisimage.o \
stm32image.o \
$(ROCKCHIP_OBS) \
socfpgaimage.o \
lib/crc16.o \
lib/sha1.o \
lib/sha256.o \
common/hash.o \