OpenCloudOS-Kernel/include/linux/dma-buf-map.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Pointer to dma-buf-mapped memory, plus helpers.
 */

#ifndef __DMA_BUF_MAP_H__
#define __DMA_BUF_MAP_H__

#include <linux/io.h>

/**
 * struct dma_buf_map - Pointer to vmap'ed dma-buf memory.
 * @vaddr_iomem:	The buffer's address if in I/O memory
 * @vaddr:		The buffer's address if in system memory
 * @is_iomem:		True if the dma-buf memory is located in I/O
 *			memory, or false otherwise.
 */
struct dma_buf_map {
	union {
		void __iomem *vaddr_iomem;
		void *vaddr;
	};
	bool is_iomem;
};

/**
 * DMA_BUF_MAP_INIT_VADDR - Initializes struct dma_buf_map to an address in system memory
 * @vaddr:	A system-memory address
 */
#define DMA_BUF_MAP_INIT_VADDR(vaddr_) \
	{ \
		.vaddr = (vaddr_), \
		.is_iomem = false, \
	}

/**
 * dma_buf_map_set_vaddr - Sets a dma-buf mapping structure to an address in system memory
 * @map:	The dma-buf mapping structure
 * @vaddr:	A system-memory address
 *
 * Sets the address and clears the I/O-memory flag.
 */
static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
{
	map->vaddr = vaddr;
	map->is_iomem = false;
}

/**
 * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
 * @lhs:	The dma-buf mapping structure
 * @rhs:	A dma-buf mapping structure to compare with
 *
 * Two dma-buf mapping structures are equal if they both refer to the same type of memory
 * and to the same address within that memory.
 *
 * Returns:
 * True is both structures are equal, or false otherwise.
 */
static inline bool dma_buf_map_is_equal(const struct dma_buf_map *lhs,
					const struct dma_buf_map *rhs)
{
	if (lhs->is_iomem != rhs->is_iomem)
		return false;
	else if (lhs->is_iomem)
		return lhs->vaddr_iomem == rhs->vaddr_iomem;
	else
		return lhs->vaddr == rhs->vaddr;
}

/**
 * dma_buf_map_is_null - Tests for a dma-buf mapping to be NULL
 * @map:	The dma-buf mapping structure
 *
 * Depending on the state of struct dma_buf_map.is_iomem, tests if the
 * mapping is NULL.
 *
 * Returns:
 * True if the mapping is NULL, or false otherwise.
 */
static inline bool dma_buf_map_is_null(const struct dma_buf_map *map)
{
	if (map->is_iomem)
		return !map->vaddr_iomem;
	return !map->vaddr;
}

/**
 * dma_buf_map_is_set - Tests is the dma-buf mapping has been set
 * @map:	The dma-buf mapping structure
 *
 * Depending on the state of struct dma_buf_map.is_iomem, tests if the
 * mapping has been set.
 *
 * Returns:
 * True if the mapping is been set, or false otherwise.
 */
static inline bool dma_buf_map_is_set(const struct dma_buf_map *map)
{
	return !dma_buf_map_is_null(map);
}

/**
 * dma_buf_map_clear - Clears a dma-buf mapping structure
 * @map:	The dma-buf mapping structure
 *
 * Clears all fields to zero; including struct dma_buf_map.is_iomem. So
 * mapping structures that were set to point to I/O memory are reset for
 * system memory. Pointers are cleared to NULL. This is the default.
 */
static inline void dma_buf_map_clear(struct dma_buf_map *map)
{
	if (map->is_iomem) {
		map->vaddr_iomem = NULL;
		map->is_iomem = false;
	} else {
		map->vaddr = NULL;
	}
}

#endif /* __DMA_BUF_MAP_H__ */