iommu: Add support for delayed unmapping of ion/dma_buf buffer

Add new APIs to allow clients to map and unmap dma_buffers created by
ION. The call to the unmap API will not actually do the unmapping from the
IOMMU. The unmapping will occur when the ION/dma_buf buffer is actually
freed. This behavior can be disabled with DMA_ATTR_NO_DELAYED_UNMAP

Change-Id: Ic4dbd3b582eb0388020c650cab5fbb1dad67ae81
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/include/linux/msm_dma_iommu_mapping.h b/include/linux/msm_dma_iommu_mapping.h
new file mode 100644
index 000000000000..a185578915df
--- /dev/null
+++ b/include/linux/msm_dma_iommu_mapping.h
@@ -0,0 +1,61 @@
+/* Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _LINUX_MSM_DMA_IOMMU_MAPPING_H
+#define _LINUX_MSM_DMA_IOMMU_MAPPING_H
+
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-mapping.h>
+
+enum msm_dma_map_attr {
+	MSM_DMA_ATTR_NO_DELAYED_UNMAP = 0x1,
+};
+
+/*
+* This function is not taking a reference to the dma_buf here. It is expected
+* that clients hold reference to the dma_buf until they are done with mapping
+* and unmapping.
+*/
+int msm_dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents,
+		   enum dma_data_direction dir, struct dma_buf *dma_buf,
+		   int flags);
+
+static inline int msm_dma_map_sg_lazy(struct device *dev,
+			       struct scatterlist *sg, int nents,
+			       enum dma_data_direction dir,
+			       struct dma_buf *dma_buf)
+{
+	return msm_dma_map_sg_attrs(dev, sg, nents, dir, dma_buf, 0);
+}
+
+static inline int msm_dma_map_sg(struct device *dev, struct scatterlist *sg,
+				  int nents, enum dma_data_direction dir,
+				  struct dma_buf *dma_buf)
+{
+	return msm_dma_map_sg_attrs(dev, sg, nents, dir, dma_buf,
+			      MSM_DMA_ATTR_NO_DELAYED_UNMAP);
+}
+
+void msm_dma_unmap_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		      enum dma_data_direction dir, struct dma_buf *dma_buf);
+
+
+/*
+ * Below is private function only to be called by framework (ION) and not by
+ * clients.
+ */
+
+void msm_dma_buf_freed(void *buffer);
+
+#endif