[U-Boot] [PATCH 0/5] Create an API for safely accessing BMP header fields

[Nikita Kiryanov]

On 02/04/2013 04:19 PM, Albert ARIBAUD wrote:
> Hi Nikita,
>
> On Mon, 04 Feb 2013 14:37:06 +0200, Nikita Kiryanov
> <nikita at compulab.co.il> wrote:
>
>> Hi Albert,
>>
>> On 02/04/2013 01:57 PM, Albert ARIBAUD wrote:
>>>
>>> IIRC, you has submitted a fix so that BMP loads would result in
>>> correctly aligned fields and thus no need for accessors. Why this
>>> change of mind?
>>   >
>>
>> I did mention that I consider that fix as temporary. I believe this fix
>> is better because it addresses the issue everywhere and does so in a
>> more maintainable way (does not require the address fix to be duplicated
>> everywhere there is a problem).
>
> I actually like the new fix less, as it adds an API where there is no
> need of one -- it's not like the implementation of BMP is at risk of
> changing. What is the problem in fixing the load address at load time
> and then passing this fixed address around?

The problem is that it makes the U-Boot display subsystems broken in
terms of what kind of programming interface they provide.
The load address fix has to be applied in every code path that leads
to a BMP being loaded and read in memory. This means that anyone who
wants to implement some BMP related functionality needs to care about
this architecture/memory issue, and actively circumvent it.
This isn't good design. If I'm manipulating BMPs I should only care
about my BMPs, not hardware issues.

>
> Amicalement,
>


-- 
Regards,
Nikita.