Re: [PATCH for-7.1 00/11] hw/arm: Add NPCM8XX support

From: Hao Wu <wuhaotsh@google.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-arm <qemu-arm@nongnu.org>,
	QEMU Developers <qemu-devel@nongnu.org>,
	 Patrick Venture <venture@google.com>,
	IS20 Avi Fishman <Avi.Fishman@nuvoton.com>,
	 CS20 KFTing <kfting@nuvoton.com>,
	Havard Skinnemoen <hskinnemoen@google.com>,
	 IV00 Uri Trichter <Uri.Trichter@nuvoton.com>,
	Vishal.Soni@microsoft.com,  Titus Rwantare <titusr@google.com>
Subject: Re: [PATCH for-7.1 00/11] hw/arm: Add NPCM8XX support
Date: Thu, 21 Apr 2022 09:59:28 -0700	[thread overview]
Message-ID: <CAGcCb13ty6=8ETcvcJqUi5_o1S-3CMP_u2_wZoCvrd34siJmgg@mail.gmail.com> (raw)
In-Reply-To: <CAFEAcA9P9aYrOgo08h1qS4mWt3+GmxgDYbxC-BTrG8_e67w18w@mail.gmail.com>

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Thanks!

I can add the new CPU type to virt in a separate patch set. It might take a
while before I send out
that patch set.

Since this patch set will be dependent on that I won't send out a v2 on
this patch set until that finishes.

On Thu, Apr 21, 2022 at 9:42 AM Peter Maydell <peter.maydell@linaro.org>
wrote:

> On Thu, 21 Apr 2022 at 17:29, Hao Wu <wuhaotsh@google.com> wrote:
> >
> > Thanks for all the comments you gave! I'll go over and address them
> recently.
> >
> > For this question, The actual CPU should be cortex A35. However, I don't
> see
> > them supported in QEMU. If I inserted CPU with "cortex-a35" QEMU will
> complain:
> > qemu-system-aarch64: missing object type 'cortex-a35-arm-cpu'
> >
> > What should I do here?
>
> You need to implement the new CPU type first... This means adding
> something to target/arm/cpu64.c which will look similar to the
> existing CPU handling. You need to watch out for:
>  * getting all the ID register values right (check the TRM for the CPU)
>  * implementing whatever the right impdef system registers are
>  * checking whether QEMU is still missing support for any of the
>    architectural features that the A35 implements (what QEMU
>    supports is listed in docs/system/arm/emulation.rst)
>
> It's typically not much code but quite a lot of cross-checking
> against the TRM for the CPU that we're not missing pieces...
> Since you can add the A35 as a supported CPU type for the 'virt'
> board you can do A35 support as a separate patchset that doesn't
> depend on the npmc8xx work.
>
>
> https://patchew.org/QEMU/20220417174426.711829-1-richard.henderson@linaro.org/20220417174426.711829-60-richard.henderson@linaro.org/
> is an example of how to add a new CPU (in that case the A76), at
> the end of a large patchset from RTH that's still going through
> code review.
>
> -- PMM
>

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