Re: [PATCH 3/3] hwrng: msm - Add support for prng v2

[PrasannaKumar Muralidharan]

Hi Vinod,

On 20 June 2018 at 11:02, Vinod <vkoul@xxxxxxxxxx> wrote:
> On 19-06-18, 22:28, Herbert Xu wrote:
>> On Mon, Jun 18, 2018 at 07:42:59PM +0530, Vinod Koul wrote:
>> > Qcom 8996 and later chips support prng v2 where we need to only
>> > implement .read callback for hwrng.
>> >
>> > Add a new table for v2 which supports this and get version required for
>> > driver data.
>> >
>> > Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
>>
>> Is this really a pseudo-RNG? If so it needs to be moved over to
>> the algif_rng interface.
>>
>> hwrng is for true hardware RNGs only, because it may be directly
>> fed into /dev/random.
>
> I am trying to find how how much random output this hardware generates.
>
> Meanwhile, can you please point out examples/Documentation for algif_rng
> and if any test tools for this?

As Herbert suggested exynos rng is a good example. It was wrongly
using hwrng framework then switched to using crypto framework.

I have a patch for msm rng using crypto framework, only compile tested
though. You can find the patch at
https://pastebin.ubuntu.com/p/44r6BJgBkN/. I am having a hard time
sending patches via git send-email form a gmail account so I have put
it in pastebin. Feel free to use it if that is useful.

Regards,
PrasannaKumar