dma-direct: provide generic support for uncached kernel segments
A few architectures support uncached kernel segments. In that case we get an uncached mapping for a given physica address by using an offset in the uncached segement. Implement support for this scheme in the generic dma-direct code instead of duplicating it in arch hooks. Signed-off-by: Christoph Hellwig <hch@lst.de>
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c30700db9e
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@ -260,6 +260,14 @@ config ARCH_HAS_SET_MEMORY
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config ARCH_HAS_SET_DIRECT_MAP
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bool
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#
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# Select if arch has an uncached kernel segment and provides the
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# uncached_kernel_address / cached_kernel_address symbols to use it
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#
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config ARCH_HAS_UNCACHED_SEGMENT
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select ARCH_HAS_DMA_PREP_COHERENT
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bool
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# Select if arch init_task must go in the __init_task_data section
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config ARCH_TASK_STRUCT_ON_STACK
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bool
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@ -80,4 +80,7 @@ static inline void arch_dma_prep_coherent(struct page *page, size_t size)
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}
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#endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */
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void *uncached_kernel_address(void *addr);
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void *cached_kernel_address(void *addr);
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#endif /* _LINUX_DMA_NONCOHERENT_H */
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@ -158,6 +158,13 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
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*dma_handle = phys_to_dma(dev, page_to_phys(page));
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}
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memset(ret, 0, size);
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if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
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!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT)) {
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arch_dma_prep_coherent(page, size);
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ret = uncached_kernel_address(ret);
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}
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return ret;
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}
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@ -173,13 +180,18 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
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if (force_dma_unencrypted())
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set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
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if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
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!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT))
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cpu_addr = cached_kernel_address(cpu_addr);
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__dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));
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}
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void *dma_direct_alloc(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
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{
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if (!dev_is_dma_coherent(dev))
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if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
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!dev_is_dma_coherent(dev))
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return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
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return dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
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}
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@ -187,7 +199,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
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void dma_direct_free(struct device *dev, size_t size,
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void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
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{
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if (!dev_is_dma_coherent(dev))
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if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) &&
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!dev_is_dma_coherent(dev))
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arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
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else
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dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
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