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Subject[PATCH v6 12/19] swiotlb: don't assume that io_tlb_start-io_tlb_end is coherent
Date
The swiotlb code has appropriate calls to dma_mark_clean in place for
buffers passed to swiotlb_map_page as an argument. However it assumes
that the swiotlb bounce buffer (io_tlb_start-io_tlb_end) is already
coherent and doesn't need any calls to dma_mark_clean.

On ARM the swiotlb bounce buffer is not coherent (the memory is
writealloc while it should be bufferable) and therefore we need to call
dma_mark_clean appropriately on the bounce buffer code paths too.

Note that most architecures have an empty dma_mark_clean implementation
anyway.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
lib/swiotlb.c | 13 ++++++++++---
1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 4e8686c..eb45d17 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -515,6 +515,7 @@ found:
io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
+ dma_mark_clean(phys_to_virt(tlb_addr), size);

return tlb_addr;
}
@@ -547,7 +548,10 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
* First, sync the memory before unmapping the entry
*/
if (orig_addr && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+ {
+ dma_mark_clean(phys_to_virt(tlb_addr), size);
swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
+ }

/*
* Return the buffer to the free list by setting the corresponding
@@ -587,17 +591,20 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,

switch (target) {
case SYNC_FOR_CPU:
- if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
+ if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)) {
+ dma_mark_clean(phys_to_virt(tlb_addr), size);
swiotlb_bounce(orig_addr, tlb_addr,
size, DMA_FROM_DEVICE);
+ }
else
BUG_ON(dir != DMA_TO_DEVICE);
break;
case SYNC_FOR_DEVICE:
- if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
+ if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) {
swiotlb_bounce(orig_addr, tlb_addr,
size, DMA_TO_DEVICE);
- else
+ dma_mark_clean(phys_to_virt(tlb_addr), size);
+ } else
BUG_ON(dir != DMA_FROM_DEVICE);
break;
default:
--
1.7.2.5


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