Building leon3 prom image for testing on renode

[Alan Cudmore]

Hi Mazaya,

On Tue, Jul 18, 2023 at 8:35 PM Muhammad Sulthan Mazaya <
msulthanmazaya at gmail.com> wrote:

> Hi Alan,
>
> > Also, as you mentioned, the renode Zephyr example runs directly from RAM
> without a prom image. Is it that the RTEMS LEON3 BSP relies on
> initialization done by the boot prom (GRMON or MKPROM2 based boot code)?
>
> Do you or anyone on the devel mailing list know where/how can I check
> which kind of initialization rtems leon3 bsp rely on? Sorry, I am fairly
> new to this
>
> The prom image source code is pretty simple, but it would take a little
bit of time (for me at least) to decode since it is in SPARC assembly
language:
The code:
https://github.com/TUT-ASI/leon3-grlib-gpl-mirror/blob/master/software/leon3/prom.S
And the prom.h header they use for the renode prom image:
https://github.com/antmicro/renode-rtems-leon3/blob/main/prom.h

Essentially, it is setting up the processor including the stack pointer,
and minimal configuration (AMBA Plug and play?). The idea would be to
translate what the prom.S assembly program is doing into a set of .resc
statements to program configuration registers and set up anything that
RTEMS may need to run. It may be a subset of everything that the assembly
code does - It may come down to just one or two statements. I'm not being
specific with the steps, because I'm not sure myself.. I would have to take
some time to figure out exactly what it's doing.

Here is an example for the K210 where some of the peripheral registers are
programmed in the renode resc script:
https://github.com/renode/renode/blob/master/scripts/single-node/kendryte_k210.resc#L10

Replacing the prom with resc statements is one way to solve the problem -
by understanding the assembly and the memory mapped registers that are
being programmed. The other way to solve the problem is by figuring out the
way to supply the prom.bin file to users that need to run RTEMS/LEON3
binaries on renode. One is an embedded programming problem and the other is
an automation problem. I think both are valid solutions.

Regards,
Alan



> Thank you,
> Mazaya
>
> On Tue, Jul 18, 2023 at 11:27 PM Alan Cudmore <alan.cudmore at gmail.com>
> wrote:
>
>> Hi Mazaya,
>> I wonder if it is possible to initialize the processor to the state where
>> it can run the RTEMS image in RAM without using the prom image? The
>> processor initialization would have to go in the resc script before the
>> image is loaded and started.
>> Also, as you mentioned, the renode Zephyr example runs directly from RAM
>> without a prom image. Is it that the RTEMS LEON3 BSP relies on
>> initialization done by the boot prom (GRMON or MKPROM2 based boot code)?
>>
>> https://github.com/renode/renode/blob/master/scripts/single-node/leon3_zephyr.resc
>>
>> I guess it ends up being a trade off of tooling vs. trying to program the
>> necessary initialization in the resc script.
>>
>> Regards,
>> Alan
>>
>> On Tue, Jul 18, 2023 at 2:46 AM Muhammad Sulthan Mazaya <
>> msulthanmazaya at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I was trying to implement renode for testing leon3 using rtems-test. I
>>> noticed that from the example they provide
>>> https://github.com/antmicro/renode-rtems-leon3/blob/main/leon3_rtems.resc,
>>> it seems like the renode simulator needs the prom image of leon3 to do so.
>>> I don't think an additional build step before testing a particular bsp is
>>> something supported by the build config of rtems-tools + my mentors
>>> also said it shouldn't be on the rtems-tools. Is it okay to have RSB build
>>> that for us as part of the BSP?
>>>
>>> Thank you,
>>> Mazaya
>>> _______________________________________________
>>> devel mailing list
>>> devel at rtems.org
>>> http://lists.rtems.org/mailman/listinfo/devel
>>
>>
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