powerpc/powernv: Do not set "read" flag if direction==DMA_NONE
Normally a bitmap from the iommu_table is used to track what TCE entry
is in use. Since we are going to use iommu_table without its locks and
do xchg() instead, it becomes essential not to put bits which are not
implied in the direction flag as the old TCE value (more precisely -
the permission bits) will be used to decide whether to put the page or not.
This adds iommu_direction_to_tce_perm() (its counterpart is there already)
and uses it for powernv's pnv_tce_build().
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 3c35487..1477422 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -576,15 +576,10 @@
unsigned long uaddr, enum dma_data_direction direction,
struct dma_attrs *attrs, bool rm)
{
- u64 proto_tce;
+ u64 proto_tce = iommu_direction_to_tce_perm(direction);
__be64 *tcep, *tces;
u64 rpn;
- proto_tce = TCE_PCI_READ; // Read allowed
-
- if (direction != DMA_TO_DEVICE)
- proto_tce |= TCE_PCI_WRITE;
-
tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
rpn = __pa(uaddr) >> tbl->it_page_shift;