topic use CAAM for none contiguous data in i.MX RT Crossover MCUs

use CAAM for none contiguous data

k_aboufath-scal — Thu, 28 Nov 2019 14:15:53 GMT

Hello,

I am trying to use CAAM on iMX6.

Using the provided SDK, I use QNX OS, and I managed to implement the component and use MD5 and SHA-x successfully, but only for data in a contiguous zone.

how to use the CAAM or descriptor commands to compute a hash (MD5, SHA-xxx) of a none contiguous data area?

Or, is there a descriptor command to compute a hash (MD5, SHA-xxx) on more than one data field in a single descriptor command?

The descriptor is as follows:

0xB0800007

0x8440000C

0x24540000

@Pointer to physical adress for data

data size

0x54200010

0x7C1C3EAC

Thanks

Khalid

Re: use CAAM for none contiguous data

Yuri — Fri, 29 Nov 2019 05:03:57 GMT

Hello,

CAAM uses own DMA, therefore continuous memory should be provided

by system for CAAM.

Have a great day,

Yuri

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Re: use CAAM for none contiguous data

k_aboufath-scal — Fri, 29 Nov 2019 09:30:54 GMT

Thank you,

I am developing a CAAM driver for the Hash part, I can’t guarantee and be sure that the data or the file will be stored continuously by the user of this CAAM driver.

If I calculate the MD5 for each continuous zone of the file, is there a way (or protocol) to take these MD5 to deduce the final MD5 from the whole file?

Regards

Khalid

Re: use CAAM for none contiguous data

Yuri — Tue, 03 Dec 2019 03:08:16 GMT

Hello,

Generally the CAAM supports scatter/gather for data, but customers should implement it themselves.

Use the i.MX6 Security Reference Manual for more details.

As for combining of MD5s - hardly it is possible.

Regards,

Yuri.

Re: use CAAM for none contiguous data

ma_sreelakshmi — Tue, 07 Jul 2020 13:29:26 GMT

Hello Khalid,

Could you succeed to do hashing of files using CAAM? May i know how to implement it in job descriptors?

Thanks in advance..

Best regards

Sreelakshmy