/* release the scatterlist cache */
if (attach->dma_dir != DMA_NONE)
- dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
- attach->dma_dir);
+ /*
+ * Cache sync can be skipped here, as the vb2_dc memory is
+ * allocated from device coherent memory, which means the
+ * memory locations do not require any explicit cache
+ * maintenance prior or after being used by the device.
+ */
+ dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
sg_free_table(sgt);
kfree(attach);
db_attach->priv = NULL;
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
- dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
- attach->dma_dir);
+ dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
attach->dma_dir = DMA_NONE;
}
- /* mapping to the client with new direction */
- sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
- dma_dir);
+ /*
+ * mapping to the client with new direction, no cache sync
+ * required see comment in vb2_dc_dmabuf_ops_detach()
+ */
+ sgt->nents = dma_map_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
if (!sgt->nents) {
pr_err("failed to map scatterlist\n");
mutex_unlock(lock);