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.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
---
arch/powerpc/platforms/powernv/pci.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/pci.c
b/arch/powerpc/platforms/powernv/pci.c
index 4945e87..9ec7d68 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -589,19 +589,27 @@ struct pci_ops pnv_pci_ops = {
.write = pnv_pci_write_config,
};
+static unsigned long pnv_dmadir_to_flags(enum dma_data_direction direction)
+{
+ switch (direction) {
+ case DMA_BIDIRECTIONAL:
+ case DMA_FROM_DEVICE:
+ return TCE_PCI_READ | TCE_PCI_WRITE;
+ case DMA_TO_DEVICE:
+ return TCE_PCI_READ;
+ default:
+ return 0;
+ }
+}
+
static int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
unsigned long uaddr, enum dma_data_direction direction,
struct dma_attrs *attrs, bool rm)
{
- u64 proto_tce;
+ u64 proto_tce = pnv_dmadir_to_flags(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;
--
2.0.0
--
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