[meta-xilinx] [PATCH] arm-trusted-firmware: Use constants for memory addresses

[Mike Looijmans]

On 28-09-16 17:20, Nathan Rossi wrote:
> On Wed, Sep 28, 2016 at 10:50 AM, Manjukumar Harthikote Matha
> <manjukumar.harthikote-matha at xilinx.com> wrote:
>> Hi Mike,
>>
>> <.....>
>>>>>   LD[unexport] = "1"
>>>>>
>>>>> +ZYNQMP_ATF_MEM_BASE = "0xfffe5000"
>>>>> +ZYNQMP_ATF_MEM_SIZE =    "0x16000"
>>>> Maybe reading the load address from elf might help. I think MEM_BASE
>>>> address might change going forward.
>>>>
>>>> For example:
>>>> https://github.com/Xilinx/arm-trusted-firmware/commit/eb4fa652d424b895
>>>> 7a927c6137e2ae3652b0b1bb
>>>>
>>>
>>> This patch was to accommodate that. The current version will load it at the wrong
>>> location.
>>>
>> I am looking to see if we can read from the generated elf and populate the MEM_BASE and MEM_SIZE
>> With the current patch, I think it will be maintenance burden every release, trying to mitigate it if possible.
>
> The generated bl31.elf is populated with the correct entry point address:
>    Entry point address:               0xfffe5000
>
> Which is pointing to bl31_entrypoint,
> https://github.com/Xilinx/arm-trusted-firmware/blob/eb4fa652d424b8957a927c6137e2ae3652b0b1bb/bl31/bl31.ld.S#L35
>
> Which could be used as an alternate source of the address:
>     625: 00000000fffe5000   212 FUNC    GLOBAL DEFAULT    1 bl31_entrypoint
>
> My only query is whether the ZYNQ_ATF_MEM_* variables make sense as
> overrides? Essentially if there is a potential use case when bl31
> needs to be built to execute in an older/newer environment that
> differs from the default values (of the current version used)?
>

What I really wanted is the opposite, get the address from the binary. That 
would solve the "magic number" that you have to put in the recipe. I couldn't 
find a way to do that, so I did the opposite, make sure that both code and 
recipe share the same magic number.

I had no intention of making this "configurable" or so, I just wanted it 
consistent.






Kind regards,

Mike Looijmans
System Expert

TOPIC Products
Materiaalweg 4, NL-5681 RJ Best
Postbus 440, NL-5680 AK Best
Telefoon: +31 (0) 499 33 69 79
E-mail: mike.looijmans at topicproducts.com
Website: www.topicproducts.com

Please consider the environment before printing this e-mail