summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/dma.c
diff options
context:
space:
mode:
authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-02-11 11:32:38 +1100
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-02-11 16:07:37 +1100
commitcd15b048445d0a54f7147c35a86c5a16ef231554 (patch)
tree80c7e63624143adc5d453106ec13f445438c6135 /arch/powerpc/kernel/dma.c
parentea961a828fe7250e954f086d74d9323c3d44c3e4 (diff)
powerpc/powernv: Add iommu DMA bypass support for IODA2
This patch adds the support for to create a direct iommu "bypass" window on IODA2 bridges (such as Power8) allowing to bypass iommu page translation completely for 64-bit DMA capable devices, thus significantly improving DMA performances. Additionally, this adds a hook to the struct iommu_table so that the IOMMU API / VFIO can disable the bypass when external ownership is requested, since in that case, the device will be used by an environment such as userspace or a KVM guest which must not be allowed to bypass translations. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/dma.c')
-rw-r--r--arch/powerpc/kernel/dma.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 8032b97ccdcb..ee78f6e49d64 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -191,12 +191,10 @@ EXPORT_SYMBOL(dma_direct_ops);
#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
-int dma_set_mask(struct device *dev, u64 dma_mask)
+int __dma_set_mask(struct device *dev, u64 dma_mask)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);
- if (ppc_md.dma_set_mask)
- return ppc_md.dma_set_mask(dev, dma_mask);
if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
return dma_ops->set_dma_mask(dev, dma_mask);
if (!dev->dma_mask || !dma_supported(dev, dma_mask))
@@ -204,6 +202,12 @@ int dma_set_mask(struct device *dev, u64 dma_mask)
*dev->dma_mask = dma_mask;
return 0;
}
+int dma_set_mask(struct device *dev, u64 dma_mask)
+{
+ if (ppc_md.dma_set_mask)
+ return ppc_md.dma_set_mask(dev, dma_mask);
+ return __dma_set_mask(dev, dma_mask);
+}
EXPORT_SYMBOL(dma_set_mask);
u64 dma_get_required_mask(struct device *dev)