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    SubjectRe: [PATCH v3 07/12] usb: chipidea: add a usb2 driver for ci13xxx
    Date
    On Wednesday 16 July 2014 11:15:33 Antoine Ténart wrote:
    >
    > On Wed, Jul 16, 2014 at 10:41:10AM +0200, Arnd Bergmann wrote:
    > > On Wednesday 16 July 2014 10:26:01 Antoine Ténart wrote:
    > > > +
    > > > + if (priv->dma_mask) {
    > > > + ret = dma_coerce_mask_and_coherent(&pdev->dev, priv->dma_mask);
    > > > + if (ret)
    > > > + return ret;
    > > > + }
    > > > +
    > > >
    > >
    > > As mentioned in my comment for the binding, this is the wrong way to do it.
    > > Russell has in the past converted all drivers that did this manually to
    > > do dma_coerce_mask_and_coherent() so we can spot them more easily, but we
    > > should really be doing this better for new drivers.
    > >
    > > Can you describe what the restriction is that you want to put on the dma mask?
    >
    > Some people wanted the possibility to set the DMA mask as this USB2 CI
    > driver does not do specific Berlin operation and can be reused later.
    > I don't particularly need to call dma_coerce_mask_and_coherent() in my
    > case, as far as I know.

    Ok, just remove the call then and rely on the default mask.

    > They can maybe give the restrictions they might want to put on the DMA
    > mask.

    If the restriction is from the bus, it should get handled automatically
    by the device probe as long as the correct dma-ranges property is there
    (though we have a small bug there at the moment). If there is a variation
    of ci13xxx that can't do 32-bit DMA, that should use a different compatible
    string and pass a fixed mask into dma_set_mask_and_coherent() based on
    the device.

    Arnd
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