From 2e12dceef3d3fb8d796e384aa242062d1643cad4 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 11 Apr 2019 09:19:59 +0200 Subject: [PATCH] swiotlb-xen: simplify the DMA sync method implementations Get rid of the grand multiplexer and implement the sync_single_for_cpu and sync_single_for_device methods directly, and then loop over them for the scatterlist based variants. Note that this also loses a few comments related to highlevel DMA API concepts, which have nothing to do with the swiotlb-xen implementation details. Reviewed-by: Stefano Stabellini Signed-off-by: Christoph Hellwig Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/swiotlb-xen.c | 84 ++++++++++++++++------------------------------- 1 file changed, 28 insertions(+), 56 deletions(-) diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index e40bf1b..ba55809 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -452,48 +452,28 @@ static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, xen_unmap_single(hwdev, dev_addr, size, dir, attrs); } -/* - * Make physical memory consistent for a single streaming mode DMA translation - * after a transfer. - * - * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer - * using the cpu, yet do not wish to teardown the dma mapping, you must - * call this function before doing so. At the next point you give the dma - * address back to the card, you must first perform a - * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer - */ static void -xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr, - size_t size, enum dma_data_direction dir, - enum dma_sync_target target) +xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, + size_t size, enum dma_data_direction dir) { - phys_addr_t paddr = xen_bus_to_phys(dev_addr); + phys_addr_t paddr = xen_bus_to_phys(dma_addr); - BUG_ON(dir == DMA_NONE); - - if (target == SYNC_FOR_CPU) - xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir); + xen_dma_sync_single_for_cpu(dev, dma_addr, size, dir); - /* NOTE: We use dev_addr here, not paddr! */ - if (is_xen_swiotlb_buffer(dev_addr)) - swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target); - - if (target == SYNC_FOR_DEVICE) - xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir); + if (is_xen_swiotlb_buffer(dma_addr)) + swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU); } -void -xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, - size_t size, enum dma_data_direction dir) +static void +xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, + size_t size, enum dma_data_direction dir) { - xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU); -} + phys_addr_t paddr = xen_bus_to_phys(dma_addr); -void -xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, - size_t size, enum dma_data_direction dir) -{ - xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE); + if (is_xen_swiotlb_buffer(dma_addr)) + swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE); + + xen_dma_sync_single_for_device(dev, dma_addr, size, dir); } /* @@ -538,38 +518,30 @@ out_unmap: return 0; } -/* - * Make physical memory consistent for a set of streaming mode DMA translations - * after a transfer. - * - * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules - * and usage. - */ static void -xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl, - int nelems, enum dma_data_direction dir, - enum dma_sync_target target) +xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir) { struct scatterlist *sg; int i; - for_each_sg(sgl, sg, nelems, i) - xen_swiotlb_sync_single(hwdev, sg->dma_address, - sg_dma_len(sg), dir, target); -} - -static void -xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, - int nelems, enum dma_data_direction dir) -{ - xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU); + for_each_sg(sgl, sg, nelems, i) { + xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address, + sg->length, dir); + } } static void -xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, +xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl, int nelems, enum dma_data_direction dir) { - xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE); + struct scatterlist *sg; + int i; + + for_each_sg(sgl, sg, nelems, i) { + xen_swiotlb_sync_single_for_device(dev, sg->dma_address, + sg->length, dir); + } } /* -- 2.7.4