powerpc: Use the newly added get_required_mask dma_map_ops hook

Now that the generic code has dma_map_ops set, instead of having a
messy ifdef & if block in the base dma_get_required_mask hook push
the computation into the dma ops.

If the ops fails to set the get_required_mask hook default to the
width of dma_addr_t.

This also corrects ibmbus ibmebus_dma_supported to require a 64
bit mask.  I doubt anything is checking or setting the dma mask on
that bus.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: benh@kernel.crashing.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 5ef55f3b0987..fc46fcac3921 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -1161,11 +1161,20 @@ __setup("iommu_fixed=", setup_iommu_fixed);
 
 static u64 cell_dma_get_required_mask(struct device *dev)
 {
+	struct dma_map_ops *dma_ops;
+
 	if (!dev->dma_mask)
 		return 0;
 
-	if (iommu_fixed_disabled && get_dma_ops(dev) == &dma_iommu_ops)
-		return dma_iommu_get_required_mask(dev);
+	if (!iommu_fixed_disabled &&
+			cell_iommu_get_fixed_address(dev) != OF_BAD_ADDR)
+		return DMA_BIT_MASK(64);
+
+	dma_ops = get_dma_ops(dev);
+	if (dma_ops->get_required_mask)
+		return dma_ops->get_required_mask(dev);
+
+	WARN_ONCE(1, "no get_required_mask in %p ops", dma_ops);
 
 	return DMA_BIT_MASK(64);
 }