@@ -137,6 +137,20 @@ static inline bool dma_map_direct(struct device *dev,
return dma_go_direct(dev, *dev->dma_mask, ops);
}
+#ifdef CONFIG_ARCH_HAS_DMA_MAP_DIRECT
+bool arch_dma_map_page_direct(struct device *dev, phys_addr_t addr);
+bool arch_dma_unmap_page_direct(struct device *dev, dma_addr_t dma_handle);
+bool arch_dma_map_sg_direct(struct device *dev, struct scatterlist *sg,
+ int nents);
+bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg,
+ int nents);
+#else
+#define arch_dma_map_page_direct(d, a) (0)
+#define arch_dma_unmap_page_direct(d, a) (0)
+#define arch_dma_map_sg_direct(d, s, n) (0)
+#define arch_dma_unmap_sg_direct(d, s, n) (0)
+#endif
+
dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
size_t offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
@@ -149,7 +163,8 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
if (WARN_ON_ONCE(!dev->dma_mask))
return DMA_MAPPING_ERROR;
- if (dma_map_direct(dev, ops))
+ if (dma_map_direct(dev, ops) ||
+ arch_dma_map_page_direct(dev, page_to_phys(page) + offset + size))
addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
else
addr = ops->map_page(dev, page, offset, size, dir, attrs);
@@ -165,7 +180,8 @@ void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
const struct dma_map_ops *ops = get_dma_ops(dev);
BUG_ON(!valid_dma_direction(dir));
- if (dma_map_direct(dev, ops))
+ if (dma_map_direct(dev, ops) ||
+ arch_dma_unmap_page_direct(dev, addr + size))
dma_direct_unmap_page(dev, addr, size, dir, attrs);
else if (ops->unmap_page)
ops->unmap_page(dev, addr, size, dir, attrs);
@@ -188,7 +204,8 @@ int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents,
if (WARN_ON_ONCE(!dev->dma_mask))
return 0;
- if (dma_map_direct(dev, ops))
+ if (dma_map_direct(dev, ops) ||
+ arch_dma_map_sg_direct(dev, sg, nents))
ents = dma_direct_map_sg(dev, sg, nents, dir, attrs);
else
ents = ops->map_sg(dev, sg, nents, dir, attrs);
@@ -207,7 +224,8 @@ void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
BUG_ON(!valid_dma_direction(dir));
debug_dma_unmap_sg(dev, sg, nents, dir);
- if (dma_map_direct(dev, ops))
+ if (dma_map_direct(dev, ops) ||
+ arch_dma_unmap_sg_direct(dev, sg, nents))
dma_direct_unmap_sg(dev, sg, nents, dir, attrs);
else if (ops->unmap_sg)
ops->unmap_sg(dev, sg, nents, dir, attrs);
@@ -20,6 +20,10 @@ config DMA_OPS
config DMA_OPS_BYPASS
bool
+# Lets platform IOMMU driver choose between bypass and IOMMU
+config ARCH_HAS_DMA_MAP_DIRECT
+ bool
+
config NEED_SG_DMA_LENGTH
bool
At the moment we allow bypassing DMA ops only when we can do this for the entire RAM. However there are configs with mixed type memory where we could still allow bypassing IOMMU in most cases; POWERPC with persistent memory is one example. This adds an arch hook to determine where bypass can still work and we invoke direct DMA API. The following patch checks the bus limit on POWERPC to allow or disallow direct mapping. This adds a CONFIG_ARCH_HAS_DMA_SET_MASK config option to make arch_xxxx hooks no-op by default. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- Changes: v4: * wrapped long lines --- kernel/dma/mapping.c | 26 ++++++++++++++++++++++---- kernel/dma/Kconfig | 4 ++++ 2 files changed, 26 insertions(+), 4 deletions(-)