diff options
| -rw-r--r-- | common/crc8.c | 9 | ||||
| -rw-r--r-- | include/crc8.h | 14 |
2 files changed, 20 insertions, 3 deletions
diff --git a/common/crc8.c b/common/crc8.c index b752698d14..ca32d5a19c 100644 --- a/common/crc8.c +++ b/common/crc8.c @@ -5,9 +5,14 @@ #include "common.h" #include "crc8.h" -uint8_t crc8(const uint8_t *data, int len) +inline uint8_t crc8(const uint8_t *data, int len) { - unsigned crc = 0; + return crc8_arg(data, len, 0); +} + +uint8_t crc8_arg(const uint8_t *data, int len, uint8_t previous_crc) +{ + unsigned crc = previous_crc << 8; int i, j; for (j = len; j; j--, data++) { diff --git a/include/crc8.h b/include/crc8.h index de0dc196f9..c98d65ce4d 100644 --- a/include/crc8.h +++ b/include/crc8.h @@ -13,9 +13,21 @@ * algorithm would be faster, but for only a few bytes it isn't worth the code * size. * @param data uint8_t *, input, a pointer to input data - * @param len int, input, size of iput data in byte + * @param len int, input, size of input data in bytes * @return the crc-8 of the input data. */ uint8_t crc8(const uint8_t *data, int len); +/** + * crc8_arg + * Return CRC-8 of the data, based upon pre-calculated partial CRC of previous + * data. + * @param data uint8_t *, input, a pointer to input data + * @param len int, input, size of input data in bytes + * @param previous_crc uint8_t, input, pre-calculated CRC of previous data. + * Seed with zero for a new calculation (or use the result of crc8()). + * @return the crc-8 of the input data. + */ +uint8_t crc8_arg(const uint8_t *data, int len, uint8_t previous_crc); + #endif /* __CROS_EC_CRC8_H */ |