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-rw-r--r--lib/crc8.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/lib/crc8.c b/lib/crc8.c
index 8b68a29e40..51d540fbcb 100644
--- a/lib/crc8.c
+++ b/lib/crc8.c
@@ -6,20 +6,27 @@
#include "linux/crc8.h"
-unsigned int crc8(const unsigned char *vptr, int len)
+#define POLY (0x1070U << 3)
+
+static unsigned char _crc8(unsigned short data)
{
- const unsigned char *data = vptr;
- unsigned int crc = 0;
- int i, j;
-
- for (j = len; j; j--, data++) {
- crc ^= (*data << 8);
- for (i = 8; i; i--) {
- if (crc & 0x8000)
- crc ^= (0x1070 << 3);
- crc <<= 1;
- }
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ if (data & 0x8000)
+ data = data ^ POLY;
+ data = data << 1;
}
- return (crc >> 8) & 0xff;
+ return (unsigned char)(data >> 8);
+}
+
+unsigned int crc8(unsigned int crc, const unsigned char *vptr, int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ crc = _crc8((crc ^ vptr[i]) << 8);
+
+ return crc;
}