[PATCH v3 03/24] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE
From: Alexey Kardashevskiy <hidden>
Date: 2015-01-29 09:22:26
Also in:
linuxppc-dev
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted> Reviewed-by: David Gibson <redacted> --- 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;
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2.0.0