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Subject: Re: dma_declare_coherent_memory and SuperH
To:     Christoph Hellwig <hch@lst.de>
Cc:     Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>, linux-sh@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20210623133205.GA28589@lst.de>
 <1a55cf69-8fe1-dca0-68c7-f978567f9ca0@landley.net>
 <20210628133858.GA21602@lst.de>
From:   Rob Landley <rob@landley.net>
Message-ID: <4d6b7c35-f2fa-b476-b814-598a812770e6@landley.net>
Date:   Mon, 28 Jun 2021 09:04:19 -0500
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On 6/28/21 8:38 AM, Christoph Hellwig wrote:
> On Sat, Jun 26, 2021 at 05:36:08PM -0500, Rob Landley wrote:
>> On 6/23/21 8:32 AM, Christoph Hellwig wrote:
>> > Hi SuperH maintainers,
>> > 
>> > I have a vague recollection that you were planning on dropping support
>> > for non-devicetree platforms, is that still the case?
>> 
>> We'd like to convert them, but have to rustle up test hardware for what _is_
>> still available. (There was some motion towards this a year or so back, but it
>> petered out because pandemic and everyone got distracted halfway through.)
>> 
>> (We should definitely START by converting the r2d board qemu emulates. :)
>> 
>> > The reason I'm asking is because all but one users of
>> > dma_declare_coherent_memory are in the sh platform setup code, and
>> > I'd really like to move towards killing this function off.
>> 
>> Understood. Is there an easy "convert to this" I could do to those callers?
> 
> Well, the replacement is to declare the device memory carveouts in the
> Device Tree.

Your plan is to eliminate the ability for non-device-tree boards to do DMA?

Rob