[PATCH v2] crypto: atmel-sha204a - drop hwrng quality reduction for ATSHA204A

[Ard Biesheuvel]

On Tue, 28 Apr 2026, at 15:24, Marek Behún wrote:
> Hi Thorsten,
>
> Bill also wrote about ATSHA204A [1]
>
>   My best guess as to what's going on here is that the device has a
>   ring-oscillator based entropy source, but that it generates only a few bits
>   of entropy for each use.  It seems to be called before generating each
>   32-byte "random" value, which is why the second set of 32-bit values have
>   more possible values, and the 3rd has even more.  However, the number of
>   unique values in the final column of 32*N byte values is always equal to
>   the number of unique values of the entire string of bytes.
>
> If this is true that the device generates <256 true random bits and then
> mixes in non-volatile pseudorandom number generator to produce 256 bits,
> then the quality should not be set to full 1024.
>

This post is about the Hashlet, which has a ATSHA204 not ATSHA204A.