[POWERPC] Fix potential cell IOMMU bug when switching back to default DMA ops

If we get a 64-bit dma mask we switch to the fixed ops and call
cell_dma_dev_setup().  If the driver then switches back to a 32-bit dma
mask for any reason we don't call cell_dma_dev_setup() again, which
has the potential to leave bogus data in dev->archdata.dma_data.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 1f7b25474086..5cdcd3638250 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -841,19 +841,18 @@ static int dma_set_mask_and_switch(struct device *dev, u64 dma_mask)
         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
                 return -EIO;
 
-        if (dma_mask == DMA_BIT_MASK(64)) {
-                if (cell_iommu_get_fixed_address(dev) == OF_BAD_ADDR)
-                        dev_dbg(dev, "iommu: 64-bit OK, but bad addr\n");
-                else {
-                        dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
-                        set_dma_ops(dev, &dma_iommu_fixed_ops);
-                        cell_dma_dev_setup(dev);
-                }
+        if (dma_mask == DMA_BIT_MASK(64) &&
+                cell_iommu_get_fixed_address(dev) != OF_BAD_ADDR)
+        {
+                dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
+                set_dma_ops(dev, &dma_iommu_fixed_ops);
         } else {
                 dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
                 set_dma_ops(dev, get_pci_dma_ops());
         }
 
+        cell_dma_dev_setup(dev);
+
         *dev->dma_mask = dma_mask;
 
         return 0;