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authorShawn Nematbakhsh <shawnn@chromium.org>2016-03-15 16:00:09 -0700
committerchrome-bot <chrome-bot@chromium.org>2016-03-18 22:16:53 -0700
commit952b2a54e12bfbf6635a5eb225ad777814ca9c92 (patch)
tree36aeb0608546450ec382f5370d04d1142dc518ba /include/crc8.h
parentf06443e2f7020b98dbb7145bedc930327b8c25dd (diff)
downloadchrome-ec-952b2a54e12bfbf6635a5eb225ad777814ca9c92.tar.gz
crc8: Support crc calculation across non-contiguous data
Building a single buffer for crc calculation is often inefficient, so add a new function that calculates crc8 from an existing crc8. BUG=chromium:576911 BRANCH=None TEST=Manual on sentry with subsequent commit. Verify that smbus communication with battery is functional. Change-Id: I05ffedb81ffcf0c126acda5f6212b3147b1580a1 Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/333786 Commit-Ready: Shawn N <shawnn@chromium.org> Tested-by: Shawn N <shawnn@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Diffstat (limited to 'include/crc8.h')
-rw-r--r--include/crc8.h14
1 files changed, 13 insertions, 1 deletions
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 */