i.MX ProcessorsのトピックRe: DCP calculation CRC32 value is incorrect

DCP calculation CRC32 value is incorrect

limingchen — Tue, 04 Jul 2017 09:37:28 GMT

Why do I use the DCP Hash function on i.mx287 to compute the CRC32 check of the string "1234" to 0xa685c4aa, but the result I calculated using the calculator is 0x9be3e0a3? Is the algorithm different?

为什么我使用i.mx287上的DCP功能计算字符串“1234”的CRC32校验值为0xa685c4aa，但是我使用计算器算出的结果是0x9be3e0a3？是算法不一样吗？

Re: DCP calculation CRC32 value is incorrect

igorpadykov — Wed, 05 Jul 2017 02:56:13 GMT

Hi li

it uses slightly different algorithm as described below

Best regards
igor
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Re: DCP calculation CRC32 value is incorrect

limingchen — Wed, 05 Jul 2017 03:42:22 GMT

No, he said Unix cksum() is another algorithm, I used the algorithm should be the same as the DCP, but the results are not the same.

CRC32 is X32+X26+X23+X22+X16+X12+X11+X10+X8+X7+X5+X4+X2+X1+1。

Re: DCP calculation CRC32 value is incorrect

igorpadykov — Wed, 05 Jul 2017 05:43:03 GMT

seems algorithm using the calculator was different from DCP

described in Reference Manual.

Please look at DCP driver in linux-2.6.35.3/drivers/crypto/dcp.c.

~igor

Re: DCP calculation CRC32 value is incorrect

limingchen — Wed, 05 Jul 2017 08:37:13 GMT

Do you know how the crc algorithm of DCP is specific? Is there a documentation? If not the same, what is its application scenario?

Re: DCP calculation CRC32 value is incorrect

igorpadykov — Wed, 05 Jul 2017 10:15:35 GMT

sorry there is no additional documentation except provided in reference manual.