powerpc/dma: properly wire up the unmap_page and unmap_sg methods

The unmap methods need to transfer memory ownership back from the
device to the cpu by identical means as dma_sync_*_to_cpu. I'm not
sure powerpc needs to do any work in this transfer direction, but
given that it does invalidate the caches in dma_sync_*_to_cpu already
we should make sure we also do so on unmapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[mpe: s/dir/direction in dma_nommu_unmap_page()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index dbfc7056d7df7670b875c2df35bc8e2f2bf14bc8..9eb2cec15439efe9057aed5238a1fc05a5fc76de 100644 (file)
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -210,10 +210,15 @@ static int dma_nommu_map_sg(struct device *dev, struct scatterlist *sgl,
        return nents;
 }
 
-static void dma_nommu_unmap_sg(struct device *dev, struct scatterlist *sg,
+static void dma_nommu_unmap_sg(struct device *dev, struct scatterlist *sgl,
                                int nents, enum dma_data_direction direction,
                                unsigned long attrs)
 {
+       struct scatterlist *sg;
+       int i;
+
+       for_each_sg(sgl, sg, nents, i)
+               __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 }
 
 static u64 dma_nommu_get_required_mask(struct device *dev)
@@ -247,6 +252,8 @@ static inline void dma_nommu_unmap_page(struct device *dev,
                                         enum dma_data_direction direction,
                                         unsigned long attrs)
 {
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+               __dma_sync(bus_to_virt(dma_address), size, direction);
 }
 
 #ifdef CONFIG_NOT_COHERENT_CACHE