Hi Arnd,
On Mon, Jul 10, 2017 at 5:14 PM, Arnd Bergmann <[email protected]> wrote:
> Geert Uytterhoeven ran into a build error without CONFIG_HAS_DMA,
> as a result of the driver calling set_dma_ops(). While we can
> fix the build error in the dma-mapping implementation, there is
> another problem in this driver:
>
> The configuration for the DMA is done by the platform code,
> looking up information about the system from the device tree.
> This copies the information only in an incomplete way, setting
> the dma_map_ops and forcing a specific mask, but ignoring all
> settings regarding IOMMU, coherence etc.
>
> A better way to avoid the problem is to only ever pass a device
> into the dma_mapping implementation that has been setup by the
> platform code. In this case, that is the parent device, so we
> can get that pointer at probe time. Fortunately, we already have
> a pointer in the device specific structure for that, so we only
> need to modify that.
Thank you, that looks like a much better solution!
> Fixes: fb52728a9294 ("dpaa_eth: reuse the dma_ops provided by the FMan MAC
> device")
> Signed-off-by: Arnd Bergmann <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
> Not tested, please see if this works before applying!
Indeed, please test first.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
