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authorStefan Roese <sr@denx.de>2016-04-08 15:56:29 +0200
committerTom Rini <trini@konsulko.com>2016-04-11 20:48:26 -0400
commit456ecd08ec026e67a17a77baa3778c9f1b8e474d (patch)
tree300fa2792b8a7e1b958c08e4b1b4d92c48baf50d /include
parent5b2beab5cdf6209e5b4027312d8f9e2a13f1ce46 (diff)
lib/crc8: Add crc start value
To make the usage of this function more flexible, lets add the CRC start value as parameter to this function. This way it can be used by other functions requiring different start values than 0 as well. For non-zero CRC start values to work, I've reworked the function a bit. The new implementation is copied from the Linux version in drivers/i2c/i2c-core.c / i2c_smbus_pec(). Which supports non-zero CRC stating values. I've double-checked that the results for zero starting values are identical to the results from the original version of this function. Signed-off-by: Stefan Roese <sr@denx.de> Cc: Simon Glass <sjg@chromium.org> Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/crc8.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/crc8.h b/include/linux/crc8.h
index b5fd2ac9d6e..f7c300a9b1e 100644
--- a/include/linux/crc8.h
+++ b/include/linux/crc8.h
@@ -14,10 +14,11 @@
* This uses an x^8 + x^2 + x + 1 polynomial. A table-based algorithm would
* be faster, but for only a few bytes it isn't worth the code size
*
+ * @crc_start: CRC8 start value
* @vptr: Buffer to checksum
* @len: Length of buffer in bytes
* @return CRC8 checksum
*/
-unsigned int crc8(const unsigned char *vptr, int len);
+unsigned int crc8(unsigned int crc_start, const unsigned char *vptr, int len);
#endif