[PATCH v8 13/19] swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/device

From: Stefano Stabellini
Date: Thu Oct 17 2013 - 14:06:16 EST


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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