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From:   Rob Herring <robh+dt@kernel.org>
Date:   Thu, 30 Nov 2023 08:46:36 -0600
Message-ID: <CAL_JsqK_StOWTOBCR6OaAqu63_kyVKsA46qJ4ky9iSyB-yKZ2g@mail.gmail.com>
Subject: Re: [PATCH 1/7] OF: Retire dma-ranges mask workaround
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     Joerg Roedel <joro@8bytes.org>, Christoph Hellwig <hch@lst.de>,
        Vineet Gupta <vgupta@kernel.org>,
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On Wed, Nov 29, 2023 at 11:43=E2=80=AFAM Robin Murphy <robin.murphy@arm.com=
> wrote:
>
> From what I remember, the fixup adding 1 to the dma-ranges size was for
> the benefit of some early AMD Seattle DTs. Those are likely extinct by
> now, and anyone else who might have deserved to get the message has
> hopefully seen the warning in the 9 years we've had it there. The modern
> dma_range_map mechanism should happily handle odd-sized ranges with no
> ill effect, so there's little need to care anyway now. Clean it up.

The commit has a tested by for Seattle, but the series adding this was
for an issue on TI Keystone[1]. Looks like the patch adding this fixup
and warning did 2 things. It added 1 to the default mask when
'dma-ranges' was not present (which keystone needed) and added 1 if
the DT value was a mask along with the warning. It's not clear what
Seattle needed, but there was a fix to dma-ranges about a year
later[2].

I thought at some point we allowed 32-bit DTs to specify a ~0 size to
avoid having to use 2 cells to express 4G size which wouldn't have
been a warning, but I can't find any discussion on that. It would have
been earlier than 2015 I think... Anyways, there is no upstream dts
with that either, so I think we're good.

> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>  drivers/of/device.c | 16 ----------------
>  1 file changed, 16 deletions(-)

Acked-by: Rob Herring <robh@kernel.org>

[1] https://lore.kernel.org/all/1425405134-24707-1-git-send-email-m-kariche=
ri2@ti.com/
[2] https://lore.kernel.org/all/1455162671-16044-4-git-send-email-Suravee.S=
uthikulpanit@amd.com/