[Xen-devel] [PATCH v8 13/17] swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/device

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Call xen_dma_map_page, xen_dma_unmap_page, xen_dma_sync_single_for_cpu,
xen_dma_sync_single_for_device from swiotlb-xen to ensure cpu/device
coherency of the pages used for DMA, including the ones belonging to the
swiotlb buffer.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 drivers/xen/swiotlb-xen.c |   39 +++++++++++++++++++++++++++++++--------
 1 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 189b8db..4221cb5 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -378,8 +378,13 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct 
page *page,
         * buffering it.
         */
        if (dma_capable(dev, dev_addr, size) &&
-           !range_straddles_page_boundary(phys, size) && !swiotlb_force)
+           !range_straddles_page_boundary(phys, size) && !swiotlb_force) {
+               /* we are not interested in the dma_addr returned by
+                * xen_dma_map_page, only in the potential cache flushes 
executed
+                * by the function. */
+               xen_dma_map_page(dev, page, offset, size, dir, attrs);
                return dev_addr;
+       }
 
        /*
         * Oh well, have to allocate and map a bounce buffer.
@@ -388,6 +393,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct 
page *page,
        if (map == SWIOTLB_MAP_ERROR)
                return DMA_ERROR_CODE;
 
+       xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
+                                       map & ~PAGE_MASK, size, dir, attrs);
        dev_addr = xen_phys_to_bus(map);
 
        /*
@@ -410,12 +417,15 @@ EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
  * whatever the device wrote there.
  */
 static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
-                            size_t size, enum dma_data_direction dir)
+                            size_t size, enum dma_data_direction dir,
+                                struct dma_attrs *attrs)
 {
        phys_addr_t paddr = xen_bus_to_phys(dev_addr);
 
        BUG_ON(dir == DMA_NONE);
 
+       xen_dma_unmap_page(hwdev, paddr, size, dir, attrs);
+
        /* NOTE: We use dev_addr here, not paddr! */
        if (is_xen_swiotlb_buffer(dev_addr)) {
                swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
@@ -438,7 +448,7 @@ void xen_swiotlb_unmap_page(struct device *hwdev, 
dma_addr_t dev_addr,
                            size_t size, enum dma_data_direction dir,
                            struct dma_attrs *attrs)
 {
-       xen_unmap_single(hwdev, dev_addr, size, dir);
+       xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
 
@@ -461,11 +471,15 @@ xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t 
dev_addr,
 
        BUG_ON(dir == DMA_NONE);
 
+       if (target == SYNC_FOR_CPU)
+               xen_dma_sync_single_for_cpu(hwdev, paddr, size, dir);
+
        /* NOTE: We use dev_addr here, not paddr! */
-       if (is_xen_swiotlb_buffer(dev_addr)) {
+       if (is_xen_swiotlb_buffer(dev_addr))
                swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
-               return;
-       }
+
+       if (target == SYNC_FOR_DEVICE)
+               xen_dma_sync_single_for_cpu(hwdev, paddr, size, dir);
 
        if (dir != DMA_FROM_DEVICE)
                return;
@@ -536,8 +550,17 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct 
scatterlist *sgl,
                                return DMA_ERROR_CODE;
                        }
                        sg->dma_address = xen_phys_to_bus(map);
-               } else
+               } else {
+                       /* we are not interested in the dma_addr returned by
+                        * xen_dma_map_page, only in the potential cache 
flushes executed
+                        * by the function. */
+                       xen_dma_map_page(hwdev, pfn_to_page(paddr >> 
PAGE_SHIFT),
+                                               paddr & ~PAGE_MASK,
+                                               sg->length,
+                                               dir,
+                                               attrs);
                        sg->dma_address = dev_addr;
+               }
                sg_dma_len(sg) = sg->length;
        }
        return nelems;
@@ -559,7 +582,7 @@ xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct 
scatterlist *sgl,
        BUG_ON(dir == DMA_NONE);
 
        for_each_sg(sgl, sg, nelems, i)
-               xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir);
+               xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, 
attrs);
 
 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
-- 
1.7.2.5


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