[U-Boot] [PATCH v1 0/4] arm: socfgpa: support of-platdata

[Marek Vasut]

On 1/8/19 7:56 AM, Simon Goldschmidt wrote:
> On Mon, Jan 7, 2019 at 11:59 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 1/7/19 10:14 PM, Simon Goldschmidt wrote:
>>> This is an initial attempt to support OF_PLATDATA for socfpga gen5.
>>>
>>> There are two motivations for this:
>>> a) reduce code size to eventually support secure boot (where SPL has to
>>>    authenticate the next stage by loading/checking U-Boot from a FIT
>>>    image)
>>> b) to support the cyclone 5 boot ROM's CRC check on the SPL in SRAM
>>>    (on warm-restart), all bytes to check need to be in one piece. With
>>>    OF_SEPARATE, this is not the case (.bss is between .rodata and the
>>>    DTB). Since OF_EMBEDDED has been discouraged, OF_PLATDATA seems to
>>>    be a good solution.
>>
>> I'd much prefer parsing the DT (and thus, decoupling the SW from HW)
>> than having some ad-hoc plat data again if we can avoid that.
> 
> So you're against the whole OF_PLATDATA thing or how should I understand
> that?

If we can avoid it, I'd prefer to do so.

> It's not really ad-hoc, it's the DT converted to C structs. It's just in another
> format, but it's still (sort of) decoupled SW from HW.
> 
> As written above, I have two goals I want to achieve with this. Right now, I
> cannot enable verified boot in SPL because the available OCRAM cannot
> hold all the code. And it seemed to me OF_PLATDATA could help me there.

Well this might be a long shot, but I discussed this lack of OCRAM
during 35C3 and there was a suggestion to lock L2 cache lines above ROM
(so there's some backing store) and use that as extra SRAM. Would that
help you ?

-- 
Best regards,
Marek Vasut