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Date: Wed, 6 Nov 2013 16:46:31 +0000
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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To: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robherring2@gmail.com>, Russell King <linux@arm.linux.org.uk>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <stefano.stabellini@eu.citrix.com>,
        Rob Herring <rob.herring@calxeda.com>
Subject: Re: [PATCH] of: set dma_mask to point to coherent_dma_mask
In-Reply-To: <20131102180724.D8FC5C40F02@trevor.secretlab.ca>
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References: <1383109522-6879-1-git-send-email-robherring2@gmail.com> <20131102180724.D8FC5C40F02@trevor.secretlab.ca>
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On Sat, 2 Nov 2013, Grant Likely wrote:
> On Wed, 30 Oct 2013 00:05:22 -0500, Rob Herring <robherring2@gmail.com> wrote:
> > From: Rob Herring <rob.herring@calxeda.com>
> > 
> > Platform devices created by DT code don't initialize dma_mask pointer to
> > anything. Set it to coherent_dma_mask by default if the architecture
> > code has not set it.
> > 
> > Signed-off-by: Rob Herring <rob.herring@calxeda.com>
> 
> I believe this is okay. I haven't done any testing to back up that
> opinion though.

Tested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

 
> > I think this is at least part of what is needed to fix dma_mask issue
> > raised by Stefano [1]. Things should work AFAICT with just this, but
> > I suppose the xgmac driver needs to set the mask as well (not relying
> > on the default), but some pointing the dma_mask to a valid value is
> > needed first.
> > 
> > Rob
> > 
> > [1] http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg528236.html
> > 
> >  drivers/of/platform.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > index f6dcde2..fce088e 100644
> > --- a/drivers/of/platform.c
> > +++ b/drivers/of/platform.c
> > @@ -215,6 +215,8 @@ static struct platform_device *of_platform_device_create_pdata(
> >  	dev->archdata.dma_mask = 0xffffffffUL;
> >  #endif
> >  	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> > +	if (!dev->dev.dma_mask)
> > +		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
> >  	dev->dev.bus = &platform_bus_type;
> >  	dev->dev.platform_data = platform_data;
> >