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Date:   Thu, 16 Jun 2022 13:13:02 +0100
Message-ID: <87y1xw3iy9.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     Matt Ranostay <mranostay@ti.com>, Nishanth Menon <nm@ti.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: dts: ti: k3-j721s2: fix overlapping GICD memory region
In-Reply-To: <9b005c7d-e434-c215-288d-3926f483b07a@arm.com>
References: <20220616105112.289719-1-mranostay@ti.com>
        <9b005c7d-e434-c215-288d-3926f483b07a@arm.com>
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On Thu, 16 Jun 2022 13:07:23 +0100,
Robin Murphy <robin.murphy@arm.com> wrote:
> 
> On 2022-06-16 11:51, Matt Ranostay wrote:
> > GICD region was overlapping with GICR causing the latter to not map
> > successfully, and in turn the gic-v3 driver would fail to initialize.
> > 
> > This issue was hidden till commit 2b2cd74a06c3 ("irqchip/gic-v3: Claim iomem resources")
> > replaced of_iomap() calls with of_io_request_and_map() that internally
> > called request_mem_region().
> > 
> > Respective console output before this patchset:
> > 
> > [    0.000000] GICv3: /bus@100000/interrupt-controller@1800000: couldn't map region 0
> 
> Oh, it's nice that this finds bugs, but it seems I hadn't fully
> considered that making the simple easy change in the DT paths results
> in different behaviour from ACPI.
> 
> Marc, would you like a fix for this to remain non-fatal even in the
> face of a dodgy DT, or are you happy with being a bit stricter now?

I'd rather we work around it. I shout at people for breaking existing
DTs, so this should apply to the GIC as well. A nice WARN_ON_ONCE()
should do, if you don't mind writing the patch.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.