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

[Nathan Rossi]

On Sat, Oct 1, 2016 at 1:47 AM, Manjukumar Harthikote Matha
<manjukumar.harthikote-matha at xilinx.com> wrote:
>
>
>> -----Original Message-----
>> From: Mike Looijmans [mailto:mike.looijmans at topic.nl]
>> Sent: Friday, September 30, 2016 12:32 AM
>> To: Nathan Rossi
>> Cc: Manjukumar Harthikote Matha; meta-xilinx at yoctoproject.org
>> Subject: Re: [meta-xilinx] [PATCH] arm-trusted-firmware: Use constants for memory
>> addresses
>>
>> On 29-09-16 16:22, Nathan Rossi wrote:
>> > On Thu, Sep 29, 2016 at 7:46 PM, Mike Looijmans <mike.looijmans at topic.nl>
>> wrote:
>> >> 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.
>> >>
>> >>
>> >
>> > That makes it simpler then :). I have a sent a patch that does the
>> > dynamic reading from the elf to solve this. If you could please give
>> > it a test and let me know that it works as you expect.
>>
>> Looks fine, and a lot better than what I came up with. Probably won't be able
>> to test today though.

Did you manage to get around to giving it a test Mike? Would like to
have some confirmation that it works in a functional environment
before I merge it :).

>>
>
>
> Whats the patch, is it on mailing list?

Sorry didn't see your query. The patch is here:
https://lists.yoctoproject.org/pipermail/meta-xilinx/2016-September/002083.html

And staged here at the moment:
https://github.com/nathanrossi/meta-xilinx/commit/e3b2e6e6102ad8c2f88cd90788ca6c9de6597b5b

Regards,
Nathan

>
> Thanks
> Manju
>
>
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