From 9406a49fd1f4379409ed87b29fdaa259b0441912 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 23 Aug 2018 09:39:38 +0200 Subject: [PATCH] dma-mapping: support non-coherent devices in dma_common_get_sgtable We can use the arch_dma_coherent_to_pfn hook to provide a ->get_sgtable implementation. Note that this isn't an endorsement of this interface (which is a horrible bad idea), but it is required to move arm64 over to the generic code without a loss of functionality. Signed-off-by: Christoph Hellwig --- drivers/xen/swiotlb-xen.c | 2 +- include/linux/dma-mapping.h | 7 ++++--- kernel/dma/mapping.c | 23 ++++++++++++++++------- 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 470757d..28819a0 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -689,7 +689,7 @@ xen_swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt, handle, size, attrs); } #endif - return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size); + return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size, attrs); } static int xen_swiotlb_mapping_error(struct device *dev, dma_addr_t dma_addr) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index c3378d4..bd81e74 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -483,8 +483,8 @@ dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, #define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0) int -dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, - void *cpu_addr, dma_addr_t dma_addr, size_t size); +dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, + dma_addr_t dma_addr, size_t size, unsigned long attrs); static inline int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, @@ -496,7 +496,8 @@ dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, if (ops->get_sgtable) return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, attrs); - return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size); + return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size, + attrs); } #define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 42fd73a..58dec7a 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -202,17 +202,26 @@ EXPORT_SYMBOL(dmam_release_declared_memory); * Create scatter-list for the already allocated DMA buffer. */ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, - void *cpu_addr, dma_addr_t handle, size_t size) + void *cpu_addr, dma_addr_t dma_addr, size_t size, + unsigned long attrs) { - struct page *page = virt_to_page(cpu_addr); + struct page *page; int ret; - ret = sg_alloc_table(sgt, 1, GFP_KERNEL); - if (unlikely(ret)) - return ret; + if (!dev_is_dma_coherent(dev)) { + if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_COHERENT_TO_PFN)) + return -ENXIO; - sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); - return 0; + page = pfn_to_page(arch_dma_coherent_to_pfn(dev, cpu_addr, + dma_addr)); + } else { + page = virt_to_page(cpu_addr); + } + + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); + if (!ret) + sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); + return ret; } EXPORT_SYMBOL(dma_common_get_sgtable); -- 2.7.4