On Mon, 25 Mar 2013, Arnd Bergmann wrote:
> On Monday 25 March 2013, Alan Stern wrote:
> > >
> > > + if (!dev->dev.platform_data) {
> > > + dev->dev.platform_data = &ehci_platform_defaults;
> > > + dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
> > > + dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> >
> > In view of Felipe's comment, shouldn't these last two lines be
> > controlled by dev->dev.of_node != NULL instead?
>
> We could do that, or alternatively like this
>
> if (!dev->dev.platform_data) {
> dev->dev.platform_data = &ehci_platform_defaults;
> if (!dev->dev.dma_mask)
> dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
> if (!dev->dev.coherent_dma_mask)
> dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
>
> which would have the additional advantage that platforms can then
> call platform_device_register_resndata() to create the device
> and get a reasonable default dma mask (EHCI should always have
> 32 bit DMA, unless the platform is really screwed), rather than
> statically declaring platform devices.
That's up to platform guys. I wasn't aware of any common practice
whereby drivers would fill in a missing dma_mask, except in the DT
case.
Don't forget that EHCI is theoretically capable of using 64-bit DMA.
This may not matter for any of the platforms you're concerned about
now, but it may matter in the future.
Alan Stern
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