Re: [PATCH] of: set dma_mask to point to coherent_dma_mask

From: Stefano Stabellini
Date: Wed Nov 06 2013 - 11:48:15 EST


On Sat, 2 Nov 2013, Grant Likely wrote:
> On Wed, 30 Oct 2013 00:05:22 -0500, Rob Herring <robherring2@xxxxxxxxx> wrote:
> > From: Rob Herring <rob.herring@xxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxx>
>
> I believe this is okay. I haven't done any testing to back up that
> opinion though.

Tested-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>


> > 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@xxxxxxxxxxxxxxx/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;
> >
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