[U-Boot] Skipping relocation RAM to RAM, esp. on i.MX6?
Aneesh V
aneesh at ti.com
Thu Feb 9 07:01:49 CET 2012
On Wednesday 08 February 2012 09:53 PM, Wolfgang Denk wrote:
> Dear Aneesh V,
>
> In message<4F328B41.2050008 at ti.com> you wrote:
>>
>> But since then I changed my mind due to some other factors:
>> 1. Difficulty in debugging. I use JTAG debuggers. The workarounds
>> available are still painful and not many people know about it.
>
> We use JTAG debuggers all day, and have been doing so for well over 10
> years. All development of PPCBoot nad U-Boot has been done withJTAG
> debuggers. Relocation has never been a real problem here.
>
> Reasinf the manual may help - this is documented in detail there.
>
> This is not a good reason to reconsider.
>
>> 2. On FPGA platform, it was adding a considerable delay (I don't have
>> the exact number, but that will be in minutes). The u-boot was already
>> scaled down and was doing minimal stuff, but this one could not be
>> removed easily. That's when I created that patch.
>
> What exactly are you talking about here that "was adding a
> considerable delay" - the memory copy ? Are you really sure about
> that?
I didn't measure it part by part, but removing relocation gave a
noticeable speed-up, this platform is several orders of magnitude
slower than the real silicon. So, that should not be surprising.
>
>> 3. Un-necessary complexity without any benefit for our platform. I
>
> Maintaining different configurations of the code that behave
> differently, that can cause different types of addressing, compile
> and link and debug issues is also adding complexity. Using a single,
> well tested approach is one of the benefits even for your platform.
Fair enough. But will the new INITCALL framework help? I haven't really
followed the discussions on it. But if, as Graeme claims, all
relocation stuff is collected in one place and is easily pluggable
then maintainability is not a problem, right?
Maybe, I should stop the arguments now and wait till that framework is
a reality.
best regards,
Aneesh
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