[U-Boot] [PATCH v9 2/2] Odroid-XU3: Add documentation for Odroid-XU3

[Kevin Hilman]

Hi Simon,

Simon Glass <sjg at chromium.org> writes:

> On 8 December 2014 at 10:58, Kevin Hilman <khilman at kernel.org> wrote:

[...]

>> FWIW, the XU3 firmware is broken in other ways as well which have a
>> major impact on power management.
>>
>> First, with mainline kernels using MCPM, only 6 of 8 CPUs come
>> online.  However, even with that fixed[1], it turns out that the kernel
>> can't properly manage CCI due to secure firmware[2], which means that MCPM
>> (multi-cluster power management) can't work, and thus the low-power
>> cluster-idle states can't work, the big.LITTLE switcher cannot work, and
>> the ongoing work on energy-aware scheduling will not be useful on this
>> platform.
>>
>> Anyone know what are the chances of getting a non-secure version of the
>> firmware for this platform.  The Samsung Chromebook2 with basically the
>> same SoC (5800 compared to the 5422 on the XU3) ships with non-secure
>> firmware so all of the above mentioned features are working just fine.
>
> I have pushed on this but apparently it is not possible - they need to
> sign every BL2. The only implementation I've seen sets up the chip in
> BL2 (U-Boot SPL) so I don't think we can work around it. 

Not quite sure I'm following...

So is secure-mode enabled before BL2 is started?  Or do you mean BL2 is
where secure-mode is enabled?  If it's done in BL2, and if the
hardkernel folks are willing to sign BL2 images (which I gathered from
discussions elsewhere in this series) then it seems possible to turn off
secure-mode.

So I went to look in the u-boot-samsung repo and didn't see the code for
the SPL there.  Is the BL2 source (which I understood to be u-boot SPL)
in some other repo?

> It takes us back to the 1960s where we sent off our code at night to
> run it :-)
>
> I think the best bet is the current effort to mainline the rest of the
> Chromebook code then try to build it for XU3.

What's the status of that effort?  

>>
>> I'm working on getting these same features working on the XU3, but this
>> broken firmware as brought a halt to any real progress.
>
> Agreed, but I think this is feasible once U-Boot on XU3 is sorted out.

Let's hope so.

Kevin