include/linux/msm_dma_iommu_mapping.h

/* Copyright (c) 2015-2017, 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>

#ifdef CONFIG_QCOM_LAZY_MAPPING
/*
 * 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,
		   unsigned long attrs);

/*
 * This function takes an extra reference to the dma_buf.
 * What this means is that calling msm_dma_unmap_sg will not result in buffer's
 * iommu mapping being removed, which means that subsequent calls to lazy map
 * will simply re-use the existing iommu mapping.
 * The iommu unmapping of the buffer will occur when the ION buffer is
 * destroyed.
 * Using lazy mapping can provide a performance benefit because subsequent
 * mappings are faster.
 *
 * The limitation of using this API are that all subsequent iommu mappings
 * must be the same as the original mapping, ie they must map the same part of
 * the buffer with the same dma data direction. Also there can't be multiple
 * mappings of different parts of the buffer.
 */
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)
{
	unsigned long attrs;

	attrs = DMA_ATTR_NO_DELAYED_UNMAP;
	return msm_dma_map_sg_attrs(dev, sg, nents, dir, dma_buf, attrs);
}

void msm_dma_unmap_sg(struct device *dev, struct scatterlist *sgl, int nents,
		      enum dma_data_direction dir, struct dma_buf *dma_buf);

int msm_dma_unmap_all_for_dev(struct device *dev);

/*
 * Below is private function only to be called by framework (ION) and not by
 * clients.
 */
void msm_dma_buf_freed(void *buffer);

#else /*CONFIG_QCOM_LAZY_MAPPING*/

static inline int msm_dma_map_sg_attrs(struct device *dev,
			struct scatterlist *sg, int nents,
			enum dma_data_direction dir, struct dma_buf *dma_buf,
			unsigned long attrs)
{
	return -EINVAL;
}

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 -EINVAL;
}

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 -EINVAL;
}

static inline void msm_dma_unmap_sg(struct device *dev,
					struct scatterlist *sgl, int nents,
					enum dma_data_direction dir,
					struct dma_buf *dma_buf)
{
}

static inline int msm_dma_unmap_all_for_dev(struct device *dev)
{
	return 0;
}

static inline void msm_dma_buf_freed(void *buffer) {}
#endif /*CONFIG_QCOM_LAZY_MAPPING*/

#endif