[U-Boot] [PATCH 1/4] Exynos: Add hardware accelerated SHA 256

[Akshay Saraswat]

Hi Kim,

>On Fri, 1 Mar 2013 16:11:36 +0000
>Akshay Saraswat <akshay.s at samsung.com> wrote:
>
>> Samsung Enterprise Portal mySingle
>> 
>>  
>> 
>> Hi Kim,
>> 
>>  
>> 
>> >On Thu, 28 Feb 2013 11:08:21 +0000
>> 
>> >Akshay Saraswat <akshay.s at samsung.com> wrote:
>> 
>As you can see, no.  It looks like you didn't change anything.  I
>have to manually single-space things below.
>
>> >> So, I have incremented this value
>> >> to 500 which shall be good enough for the lowest of all frequencies. But I guess what we
>> >> need here is some formula, to calculate timeout on the basis of frequency, which is nowhere
>> >> defined.
>> 
>> >That's odd - I see a bunch of frequencies advertised in
>> >arch/arm/cpu/armv7/exynos/clock.c.
>> >Or how about using a cycle counter instead?
>> >btw, where can I find documentation for the ACE?
>> 
>> I tried with different frequencies and data sizes and found that it takes 2 to 3 msecs in all the cases.
>> Since, it is hardware accelerated encoding it is supposed to behave in this same manner.
>> But the current version of u-boot behaves mysteriously and slow downs when pressed enter for long.
>> In the above case mentioned I even saw time took to be more than 100 msecs for all the cases.
>> I think it would not be a better idea to timeout encoding acceleration.
>> But still if it is needed, cycle counter suggestion would be a great solution.
>
>it depends on whether the h/w can fault during its operation.
>
>> You can read Exynos5250 manual's "Security subsystem" section, which I referred for this.
>
>you mean this?:
>
>http://www.samsung.com/global/business/semiconductor/file/product/Exynos_5_Dual_User_Manaul_Public_REV100-0.pdf

Yes, this is the manual. But this ine is just a part of it which has been made public by Samsung.
The one I have has 64 chapters in it and security subsystems is the 57th chapter.

>
>There is no "Security subsystem" section.
>
>Kim
>

Regards,
Akshay Saraswat