[POWERPC] Fix initialization and usage of dma_mask

powerpc has a couple of bugs in the usage of dma_masks that tend to
break when drivers explicitly try to set a 32-bit mask for example.

First, the code that generates the pci devices from the OF device-tree
doesn't initialize the mask properly, then our implementation of
set_dma_mask() was trying to validate the -previous- mask value, not the
one passed in as an argument.

This fixes these problems.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 2 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index a97e23ac1976..291ffbc360c9 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -313,6 +313,7 @@ struct pci_dev *of_create_pci_dev(struct device_node *node,
 
         dev->current_state = 4;         /* unknown power state */
         dev->error_state = pci_channel_io_normal;
+        dev->dma_mask = 0xffffffff;
 
         if (!strcmp(type, "pci") || !strcmp(type, "pciex")) {
                 /* a PCI-PCI bridge */
diff --git a/include/asm-powerpc/dma-mapping.h b/include/asm-powerpc/dma-mapping.h
index f6bd804d9090..744d6bb24116 100644
--- a/include/asm-powerpc/dma-mapping.h
+++ b/include/asm-powerpc/dma-mapping.h
@@ -95,7 +95,7 @@ static inline int dma_set_mask(struct device *dev, u64 dma_mask)
                 return -EIO;
         if (dma_ops->set_dma_mask != NULL)
                 return dma_ops->set_dma_mask(dev, dma_mask);
-        if (!dev->dma_mask || !dma_supported(dev, *dev->dma_mask))
+        if (!dev->dma_mask || !dma_supported(dev, dma_mask))
                 return -EIO;
         *dev->dma_mask = dma_mask;
         return 0;