On Thu, Nov 21, 2013 at 11:01:42AM +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2013-11-20 at 23:23 +0000, Russell King - ARM Linux wrote:
> > Li Zong's patch works around the issue of a failing dma_set_mask(),
> > but as I've already said elsewhere, the real fix is to get whatever
> > created the struct device to initialise the dev->dma_mask with a
> > bus default.
> >
> > Using dma_coerce_xxx() merely makes the problem "go away" papering
> > over the issue - it's fine to do it this way, but someone should still
> > fix the broken code creating these devices...
>
> Ok, they are created by the vio bus core, so it should be doing the
> job here of setting the dma_mask pointer to a proper value.
>
> Li, can you take care of that ? Look at other bus types we have in
> there such as the macio bus etc...
Oh, hang on a moment, this is the "bus" code.
In which case, the question becomes: do vio devices ever need to have
a separate streaming DMA mask from a coherent DMA mask? If not, then
something like the following is what's needed here, and I should've
never have used dma_set_mask_and_coherent().
dma_set_mask_and_coherent() (and the other dma_set_mask() functions)
are really supposed to be used by drivers only.
arch/powerpc/kernel/vio.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/vio.c b/arch/powerpc/kernel/vio.c
index e7d0c88f621a..d771778f398e 100644
--- a/arch/powerpc/kernel/vio.c
+++ b/arch/powerpc/kernel/vio.c
@@ -1419,7 +1419,8 @@ struct vio_dev *vio_register_device_node(struct
device_node *of_node)
/* needed to ensure proper operation of coherent allocations
* later, in case driver doesn't set it explicitly */
- dma_set_mask_and_coherent(&viodev->dev, DMA_BIT_MASK(64));
+ viodev->dev.coherent_dma_mask = DMA_BIT_MASK(64);
+ viodev->dev.dma_mask = &viodev->dev.coherent_dma_mask;
}
/* register with generic device framework */
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