RE: QEMU build dependencies for new board

[Ancuta, Cristian]

Hi Peter,

Thanks for your input. 

I was indeed quite a few commits behind master, I'll give it a try now with the 
latest.

Since I see the RISCV stuff is quite new, would the associated  boards be a 
good starting point?

Best regards,
Cristian

-----Original Message-----
From: Peter Maydell <peter.maydell@linaro.org> 
Sent: Monday, November 23, 2020 8:50 PM
To: Ancuta, Cristian <cristian.ancuta@intel.com>
Cc: qemu-devel@nongnu.org
Subject: Re: QEMU build dependencies for new board

On Mon, 23 Nov 2020 at 17:31, Ancuta, Cristian <cristian.ancuta@intel.com> 
wrote:
> I’ve implemented a new CPU target in ./target/arch_name and I’m also trying 
> to add a new board to emulate that target on in system mode in 
> ./hw/arch_name. The board is based on the versatilepb, but I’ll gradually be 
> removing all the arm implementation from it, aiming for a minimal 
> implementation with just my custom cpu architecture, system bus, main memory 
> and an UART.

Incidentally, versatilepb is a really bad board to start with as a template, 
because it's one of the oldest we have, and it does a lot of things in ways 
that work but which aren't how we'd recommend writing a new board model today. 
You might be better off looking at something added more recently.

> I’ve also added all the necessary stuff required by minikconf.py in 
> ./default-configs/<target>-softmmu.mak,

This suggests you're not basing this on current head-of-git, because this is 
default-configs/targets/<target>-softmmu.mak
and default-configs/devices/<target>-softmmu.mak now.

> ./hw/<arch>/Kconfig and a source entry in ./hw/Kconfig.

> The problem is that the build system is bringing in other files that I 
> didn’t specify (CONFIG_A15MPCORE, CONFIG_A15MPCORE, CONFIG_9MPCORE, 
> etc. ), and I’m not sure how they’re ending up in 
> ./build/<target>-softmmu/config_device.mak:

This shouldn't happen, but it's not really possible to identify the exact 
problem since you don't provide your code. I would try first doing a complete 
build from scratch (ie delete the build directory) in case the problem is that 
there are stale files in the build tree that are getting picked up.
Otherwise re-double-check your default-config files to make sure they really 
don't have any CONFIG_whatever or "SELECT whatever"
in that they shouldn't. (Looking at the list of devices, an accidental "select 
REALVIEW" would have that effect.)

thanks
-- PMM